118e16ca91d76cf39bc967398c722e8b0e45444c
[linux-2.6.git] / fs / ext4 / inode.c
1 /*
2  *  linux/fs/ext4/inode.c
3  *
4  * Copyright (C) 1992, 1993, 1994, 1995
5  * Remy Card (card@masi.ibp.fr)
6  * Laboratoire MASI - Institut Blaise Pascal
7  * Universite Pierre et Marie Curie (Paris VI)
8  *
9  *  from
10  *
11  *  linux/fs/minix/inode.c
12  *
13  *  Copyright (C) 1991, 1992  Linus Torvalds
14  *
15  *  Goal-directed block allocation by Stephen Tweedie
16  *      (sct@redhat.com), 1993, 1998
17  *  Big-endian to little-endian byte-swapping/bitmaps by
18  *        David S. Miller (davem@caip.rutgers.edu), 1995
19  *  64-bit file support on 64-bit platforms by Jakub Jelinek
20  *      (jj@sunsite.ms.mff.cuni.cz)
21  *
22  *  Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
23  */
24
25 #include <linux/module.h>
26 #include <linux/fs.h>
27 #include <linux/time.h>
28 #include <linux/jbd2.h>
29 #include <linux/highuid.h>
30 #include <linux/pagemap.h>
31 #include <linux/quotaops.h>
32 #include <linux/string.h>
33 #include <linux/buffer_head.h>
34 #include <linux/writeback.h>
35 #include <linux/pagevec.h>
36 #include <linux/mpage.h>
37 #include <linux/namei.h>
38 #include <linux/uio.h>
39 #include <linux/bio.h>
40 #include <linux/workqueue.h>
41
42 #include "ext4_jbd2.h"
43 #include "xattr.h"
44 #include "acl.h"
45 #include "ext4_extents.h"
46
47 #include <trace/events/ext4.h>
48
49 #define MPAGE_DA_EXTENT_TAIL 0x01
50
51 static inline int ext4_begin_ordered_truncate(struct inode *inode,
52                                               loff_t new_size)
53 {
54         return jbd2_journal_begin_ordered_truncate(
55                                         EXT4_SB(inode->i_sb)->s_journal,
56                                         &EXT4_I(inode)->jinode,
57                                         new_size);
58 }
59
60 static void ext4_invalidatepage(struct page *page, unsigned long offset);
61
62 /*
63  * Test whether an inode is a fast symlink.
64  */
65 static int ext4_inode_is_fast_symlink(struct inode *inode)
66 {
67         int ea_blocks = EXT4_I(inode)->i_file_acl ?
68                 (inode->i_sb->s_blocksize >> 9) : 0;
69
70         return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
71 }
72
73 /*
74  * The ext4 forget function must perform a revoke if we are freeing data
75  * which has been journaled.  Metadata (eg. indirect blocks) must be
76  * revoked in all cases.
77  *
78  * "bh" may be NULL: a metadata block may have been freed from memory
79  * but there may still be a record of it in the journal, and that record
80  * still needs to be revoked.
81  *
82  * If the handle isn't valid we're not journaling, but we still need to
83  * call into ext4_journal_revoke() to put the buffer head.
84  */
85 int ext4_forget(handle_t *handle, int is_metadata, struct inode *inode,
86                 struct buffer_head *bh, ext4_fsblk_t blocknr)
87 {
88         int err;
89
90         might_sleep();
91
92         BUFFER_TRACE(bh, "enter");
93
94         jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
95                   "data mode %x\n",
96                   bh, is_metadata, inode->i_mode,
97                   test_opt(inode->i_sb, DATA_FLAGS));
98
99         /* Never use the revoke function if we are doing full data
100          * journaling: there is no need to, and a V1 superblock won't
101          * support it.  Otherwise, only skip the revoke on un-journaled
102          * data blocks. */
103
104         if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
105             (!is_metadata && !ext4_should_journal_data(inode))) {
106                 if (bh) {
107                         BUFFER_TRACE(bh, "call jbd2_journal_forget");
108                         return ext4_journal_forget(handle, bh);
109                 }
110                 return 0;
111         }
112
113         /*
114          * data!=journal && (is_metadata || should_journal_data(inode))
115          */
116         BUFFER_TRACE(bh, "call ext4_journal_revoke");
117         err = ext4_journal_revoke(handle, blocknr, bh);
118         if (err)
119                 ext4_abort(inode->i_sb, __func__,
120                            "error %d when attempting revoke", err);
121         BUFFER_TRACE(bh, "exit");
122         return err;
123 }
124
125 /*
126  * Work out how many blocks we need to proceed with the next chunk of a
127  * truncate transaction.
128  */
129 static unsigned long blocks_for_truncate(struct inode *inode)
130 {
131         ext4_lblk_t needed;
132
133         needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
134
135         /* Give ourselves just enough room to cope with inodes in which
136          * i_blocks is corrupt: we've seen disk corruptions in the past
137          * which resulted in random data in an inode which looked enough
138          * like a regular file for ext4 to try to delete it.  Things
139          * will go a bit crazy if that happens, but at least we should
140          * try not to panic the whole kernel. */
141         if (needed < 2)
142                 needed = 2;
143
144         /* But we need to bound the transaction so we don't overflow the
145          * journal. */
146         if (needed > EXT4_MAX_TRANS_DATA)
147                 needed = EXT4_MAX_TRANS_DATA;
148
149         return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
150 }
151
152 /*
153  * Truncate transactions can be complex and absolutely huge.  So we need to
154  * be able to restart the transaction at a conventient checkpoint to make
155  * sure we don't overflow the journal.
156  *
157  * start_transaction gets us a new handle for a truncate transaction,
158  * and extend_transaction tries to extend the existing one a bit.  If
159  * extend fails, we need to propagate the failure up and restart the
160  * transaction in the top-level truncate loop. --sct
161  */
162 static handle_t *start_transaction(struct inode *inode)
163 {
164         handle_t *result;
165
166         result = ext4_journal_start(inode, blocks_for_truncate(inode));
167         if (!IS_ERR(result))
168                 return result;
169
170         ext4_std_error(inode->i_sb, PTR_ERR(result));
171         return result;
172 }
173
174 /*
175  * Try to extend this transaction for the purposes of truncation.
176  *
177  * Returns 0 if we managed to create more room.  If we can't create more
178  * room, and the transaction must be restarted we return 1.
179  */
180 static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
181 {
182         if (!ext4_handle_valid(handle))
183                 return 0;
184         if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1))
185                 return 0;
186         if (!ext4_journal_extend(handle, blocks_for_truncate(inode)))
187                 return 0;
188         return 1;
189 }
190
191 /*
192  * Restart the transaction associated with *handle.  This does a commit,
193  * so before we call here everything must be consistently dirtied against
194  * this transaction.
195  */
196  int ext4_truncate_restart_trans(handle_t *handle, struct inode *inode,
197                                  int nblocks)
198 {
199         int ret;
200
201         /*
202          * Drop i_data_sem to avoid deadlock with ext4_get_blocks At this
203          * moment, get_block can be called only for blocks inside i_size since
204          * page cache has been already dropped and writes are blocked by
205          * i_mutex. So we can safely drop the i_data_sem here.
206          */
207         BUG_ON(EXT4_JOURNAL(inode) == NULL);
208         jbd_debug(2, "restarting handle %p\n", handle);
209         up_write(&EXT4_I(inode)->i_data_sem);
210         ret = ext4_journal_restart(handle, blocks_for_truncate(inode));
211         down_write(&EXT4_I(inode)->i_data_sem);
212
213         return ret;
214 }
215
216 /*
217  * Called at the last iput() if i_nlink is zero.
218  */
219 void ext4_delete_inode(struct inode *inode)
220 {
221         handle_t *handle;
222         int err;
223
224         if (ext4_should_order_data(inode))
225                 ext4_begin_ordered_truncate(inode, 0);
226         truncate_inode_pages(&inode->i_data, 0);
227
228         if (is_bad_inode(inode))
229                 goto no_delete;
230
231         handle = ext4_journal_start(inode, blocks_for_truncate(inode)+3);
232         if (IS_ERR(handle)) {
233                 ext4_std_error(inode->i_sb, PTR_ERR(handle));
234                 /*
235                  * If we're going to skip the normal cleanup, we still need to
236                  * make sure that the in-core orphan linked list is properly
237                  * cleaned up.
238                  */
239                 ext4_orphan_del(NULL, inode);
240                 goto no_delete;
241         }
242
243         if (IS_SYNC(inode))
244                 ext4_handle_sync(handle);
245         inode->i_size = 0;
246         err = ext4_mark_inode_dirty(handle, inode);
247         if (err) {
248                 ext4_warning(inode->i_sb, __func__,
249                              "couldn't mark inode dirty (err %d)", err);
250                 goto stop_handle;
251         }
252         if (inode->i_blocks)
253                 ext4_truncate(inode);
254
255         /*
256          * ext4_ext_truncate() doesn't reserve any slop when it
257          * restarts journal transactions; therefore there may not be
258          * enough credits left in the handle to remove the inode from
259          * the orphan list and set the dtime field.
260          */
261         if (!ext4_handle_has_enough_credits(handle, 3)) {
262                 err = ext4_journal_extend(handle, 3);
263                 if (err > 0)
264                         err = ext4_journal_restart(handle, 3);
265                 if (err != 0) {
266                         ext4_warning(inode->i_sb, __func__,
267                                      "couldn't extend journal (err %d)", err);
268                 stop_handle:
269                         ext4_journal_stop(handle);
270                         goto no_delete;
271                 }
272         }
273
274         /*
275          * Kill off the orphan record which ext4_truncate created.
276          * AKPM: I think this can be inside the above `if'.
277          * Note that ext4_orphan_del() has to be able to cope with the
278          * deletion of a non-existent orphan - this is because we don't
279          * know if ext4_truncate() actually created an orphan record.
280          * (Well, we could do this if we need to, but heck - it works)
281          */
282         ext4_orphan_del(handle, inode);
283         EXT4_I(inode)->i_dtime  = get_seconds();
284
285         /*
286          * One subtle ordering requirement: if anything has gone wrong
287          * (transaction abort, IO errors, whatever), then we can still
288          * do these next steps (the fs will already have been marked as
289          * having errors), but we can't free the inode if the mark_dirty
290          * fails.
291          */
292         if (ext4_mark_inode_dirty(handle, inode))
293                 /* If that failed, just do the required in-core inode clear. */
294                 clear_inode(inode);
295         else
296                 ext4_free_inode(handle, inode);
297         ext4_journal_stop(handle);
298         return;
299 no_delete:
300         clear_inode(inode);     /* We must guarantee clearing of inode... */
301 }
302
303 typedef struct {
304         __le32  *p;
305         __le32  key;
306         struct buffer_head *bh;
307 } Indirect;
308
309 static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
310 {
311         p->key = *(p->p = v);
312         p->bh = bh;
313 }
314
315 /**
316  *      ext4_block_to_path - parse the block number into array of offsets
317  *      @inode: inode in question (we are only interested in its superblock)
318  *      @i_block: block number to be parsed
319  *      @offsets: array to store the offsets in
320  *      @boundary: set this non-zero if the referred-to block is likely to be
321  *             followed (on disk) by an indirect block.
322  *
323  *      To store the locations of file's data ext4 uses a data structure common
324  *      for UNIX filesystems - tree of pointers anchored in the inode, with
325  *      data blocks at leaves and indirect blocks in intermediate nodes.
326  *      This function translates the block number into path in that tree -
327  *      return value is the path length and @offsets[n] is the offset of
328  *      pointer to (n+1)th node in the nth one. If @block is out of range
329  *      (negative or too large) warning is printed and zero returned.
330  *
331  *      Note: function doesn't find node addresses, so no IO is needed. All
332  *      we need to know is the capacity of indirect blocks (taken from the
333  *      inode->i_sb).
334  */
335
336 /*
337  * Portability note: the last comparison (check that we fit into triple
338  * indirect block) is spelled differently, because otherwise on an
339  * architecture with 32-bit longs and 8Kb pages we might get into trouble
340  * if our filesystem had 8Kb blocks. We might use long long, but that would
341  * kill us on x86. Oh, well, at least the sign propagation does not matter -
342  * i_block would have to be negative in the very beginning, so we would not
343  * get there at all.
344  */
345
346 static int ext4_block_to_path(struct inode *inode,
347                               ext4_lblk_t i_block,
348                               ext4_lblk_t offsets[4], int *boundary)
349 {
350         int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb);
351         int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb);
352         const long direct_blocks = EXT4_NDIR_BLOCKS,
353                 indirect_blocks = ptrs,
354                 double_blocks = (1 << (ptrs_bits * 2));
355         int n = 0;
356         int final = 0;
357
358         if (i_block < direct_blocks) {
359                 offsets[n++] = i_block;
360                 final = direct_blocks;
361         } else if ((i_block -= direct_blocks) < indirect_blocks) {
362                 offsets[n++] = EXT4_IND_BLOCK;
363                 offsets[n++] = i_block;
364                 final = ptrs;
365         } else if ((i_block -= indirect_blocks) < double_blocks) {
366                 offsets[n++] = EXT4_DIND_BLOCK;
367                 offsets[n++] = i_block >> ptrs_bits;
368                 offsets[n++] = i_block & (ptrs - 1);
369                 final = ptrs;
370         } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
371                 offsets[n++] = EXT4_TIND_BLOCK;
372                 offsets[n++] = i_block >> (ptrs_bits * 2);
373                 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
374                 offsets[n++] = i_block & (ptrs - 1);
375                 final = ptrs;
376         } else {
377                 ext4_warning(inode->i_sb, "ext4_block_to_path",
378                              "block %lu > max in inode %lu",
379                              i_block + direct_blocks +
380                              indirect_blocks + double_blocks, inode->i_ino);
381         }
382         if (boundary)
383                 *boundary = final - 1 - (i_block & (ptrs - 1));
384         return n;
385 }
386
387 static int __ext4_check_blockref(const char *function, struct inode *inode,
388                                  __le32 *p, unsigned int max)
389 {
390         __le32 *bref = p;
391         unsigned int blk;
392
393         while (bref < p+max) {
394                 blk = le32_to_cpu(*bref++);
395                 if (blk &&
396                     unlikely(!ext4_data_block_valid(EXT4_SB(inode->i_sb),
397                                                     blk, 1))) {
398                         ext4_error(inode->i_sb, function,
399                                    "invalid block reference %u "
400                                    "in inode #%lu", blk, inode->i_ino);
401                         return -EIO;
402                 }
403         }
404         return 0;
405 }
406
407
408 #define ext4_check_indirect_blockref(inode, bh)                         \
409         __ext4_check_blockref(__func__, inode, (__le32 *)(bh)->b_data,  \
410                               EXT4_ADDR_PER_BLOCK((inode)->i_sb))
411
412 #define ext4_check_inode_blockref(inode)                                \
413         __ext4_check_blockref(__func__, inode, EXT4_I(inode)->i_data,   \
414                               EXT4_NDIR_BLOCKS)
415
416 /**
417  *      ext4_get_branch - read the chain of indirect blocks leading to data
418  *      @inode: inode in question
419  *      @depth: depth of the chain (1 - direct pointer, etc.)
420  *      @offsets: offsets of pointers in inode/indirect blocks
421  *      @chain: place to store the result
422  *      @err: here we store the error value
423  *
424  *      Function fills the array of triples <key, p, bh> and returns %NULL
425  *      if everything went OK or the pointer to the last filled triple
426  *      (incomplete one) otherwise. Upon the return chain[i].key contains
427  *      the number of (i+1)-th block in the chain (as it is stored in memory,
428  *      i.e. little-endian 32-bit), chain[i].p contains the address of that
429  *      number (it points into struct inode for i==0 and into the bh->b_data
430  *      for i>0) and chain[i].bh points to the buffer_head of i-th indirect
431  *      block for i>0 and NULL for i==0. In other words, it holds the block
432  *      numbers of the chain, addresses they were taken from (and where we can
433  *      verify that chain did not change) and buffer_heads hosting these
434  *      numbers.
435  *
436  *      Function stops when it stumbles upon zero pointer (absent block)
437  *              (pointer to last triple returned, *@err == 0)
438  *      or when it gets an IO error reading an indirect block
439  *              (ditto, *@err == -EIO)
440  *      or when it reads all @depth-1 indirect blocks successfully and finds
441  *      the whole chain, all way to the data (returns %NULL, *err == 0).
442  *
443  *      Need to be called with
444  *      down_read(&EXT4_I(inode)->i_data_sem)
445  */
446 static Indirect *ext4_get_branch(struct inode *inode, int depth,
447                                  ext4_lblk_t  *offsets,
448                                  Indirect chain[4], int *err)
449 {
450         struct super_block *sb = inode->i_sb;
451         Indirect *p = chain;
452         struct buffer_head *bh;
453
454         *err = 0;
455         /* i_data is not going away, no lock needed */
456         add_chain(chain, NULL, EXT4_I(inode)->i_data + *offsets);
457         if (!p->key)
458                 goto no_block;
459         while (--depth) {
460                 bh = sb_getblk(sb, le32_to_cpu(p->key));
461                 if (unlikely(!bh))
462                         goto failure;
463
464                 if (!bh_uptodate_or_lock(bh)) {
465                         if (bh_submit_read(bh) < 0) {
466                                 put_bh(bh);
467                                 goto failure;
468                         }
469                         /* validate block references */
470                         if (ext4_check_indirect_blockref(inode, bh)) {
471                                 put_bh(bh);
472                                 goto failure;
473                         }
474                 }
475
476                 add_chain(++p, bh, (__le32 *)bh->b_data + *++offsets);
477                 /* Reader: end */
478                 if (!p->key)
479                         goto no_block;
480         }
481         return NULL;
482
483 failure:
484         *err = -EIO;
485 no_block:
486         return p;
487 }
488
489 /**
490  *      ext4_find_near - find a place for allocation with sufficient locality
491  *      @inode: owner
492  *      @ind: descriptor of indirect block.
493  *
494  *      This function returns the preferred place for block allocation.
495  *      It is used when heuristic for sequential allocation fails.
496  *      Rules are:
497  *        + if there is a block to the left of our position - allocate near it.
498  *        + if pointer will live in indirect block - allocate near that block.
499  *        + if pointer will live in inode - allocate in the same
500  *          cylinder group.
501  *
502  * In the latter case we colour the starting block by the callers PID to
503  * prevent it from clashing with concurrent allocations for a different inode
504  * in the same block group.   The PID is used here so that functionally related
505  * files will be close-by on-disk.
506  *
507  *      Caller must make sure that @ind is valid and will stay that way.
508  */
509 static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
510 {
511         struct ext4_inode_info *ei = EXT4_I(inode);
512         __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
513         __le32 *p;
514         ext4_fsblk_t bg_start;
515         ext4_fsblk_t last_block;
516         ext4_grpblk_t colour;
517         ext4_group_t block_group;
518         int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb));
519
520         /* Try to find previous block */
521         for (p = ind->p - 1; p >= start; p--) {
522                 if (*p)
523                         return le32_to_cpu(*p);
524         }
525
526         /* No such thing, so let's try location of indirect block */
527         if (ind->bh)
528                 return ind->bh->b_blocknr;
529
530         /*
531          * It is going to be referred to from the inode itself? OK, just put it
532          * into the same cylinder group then.
533          */
534         block_group = ei->i_block_group;
535         if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) {
536                 block_group &= ~(flex_size-1);
537                 if (S_ISREG(inode->i_mode))
538                         block_group++;
539         }
540         bg_start = ext4_group_first_block_no(inode->i_sb, block_group);
541         last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
542
543         /*
544          * If we are doing delayed allocation, we don't need take
545          * colour into account.
546          */
547         if (test_opt(inode->i_sb, DELALLOC))
548                 return bg_start;
549
550         if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
551                 colour = (current->pid % 16) *
552                         (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
553         else
554                 colour = (current->pid % 16) * ((last_block - bg_start) / 16);
555         return bg_start + colour;
556 }
557
558 /**
559  *      ext4_find_goal - find a preferred place for allocation.
560  *      @inode: owner
561  *      @block:  block we want
562  *      @partial: pointer to the last triple within a chain
563  *
564  *      Normally this function find the preferred place for block allocation,
565  *      returns it.
566  *      Because this is only used for non-extent files, we limit the block nr
567  *      to 32 bits.
568  */
569 static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
570                                    Indirect *partial)
571 {
572         ext4_fsblk_t goal;
573
574         /*
575          * XXX need to get goal block from mballoc's data structures
576          */
577
578         goal = ext4_find_near(inode, partial);
579         goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
580         return goal;
581 }
582
583 /**
584  *      ext4_blks_to_allocate: Look up the block map and count the number
585  *      of direct blocks need to be allocated for the given branch.
586  *
587  *      @branch: chain of indirect blocks
588  *      @k: number of blocks need for indirect blocks
589  *      @blks: number of data blocks to be mapped.
590  *      @blocks_to_boundary:  the offset in the indirect block
591  *
592  *      return the total number of blocks to be allocate, including the
593  *      direct and indirect blocks.
594  */
595 static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned int blks,
596                                  int blocks_to_boundary)
597 {
598         unsigned int count = 0;
599
600         /*
601          * Simple case, [t,d]Indirect block(s) has not allocated yet
602          * then it's clear blocks on that path have not allocated
603          */
604         if (k > 0) {
605                 /* right now we don't handle cross boundary allocation */
606                 if (blks < blocks_to_boundary + 1)
607                         count += blks;
608                 else
609                         count += blocks_to_boundary + 1;
610                 return count;
611         }
612
613         count++;
614         while (count < blks && count <= blocks_to_boundary &&
615                 le32_to_cpu(*(branch[0].p + count)) == 0) {
616                 count++;
617         }
618         return count;
619 }
620
621 /**
622  *      ext4_alloc_blocks: multiple allocate blocks needed for a branch
623  *      @indirect_blks: the number of blocks need to allocate for indirect
624  *                      blocks
625  *
626  *      @new_blocks: on return it will store the new block numbers for
627  *      the indirect blocks(if needed) and the first direct block,
628  *      @blks:  on return it will store the total number of allocated
629  *              direct blocks
630  */
631 static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
632                              ext4_lblk_t iblock, ext4_fsblk_t goal,
633                              int indirect_blks, int blks,
634                              ext4_fsblk_t new_blocks[4], int *err)
635 {
636         struct ext4_allocation_request ar;
637         int target, i;
638         unsigned long count = 0, blk_allocated = 0;
639         int index = 0;
640         ext4_fsblk_t current_block = 0;
641         int ret = 0;
642
643         /*
644          * Here we try to allocate the requested multiple blocks at once,
645          * on a best-effort basis.
646          * To build a branch, we should allocate blocks for
647          * the indirect blocks(if not allocated yet), and at least
648          * the first direct block of this branch.  That's the
649          * minimum number of blocks need to allocate(required)
650          */
651         /* first we try to allocate the indirect blocks */
652         target = indirect_blks;
653         while (target > 0) {
654                 count = target;
655                 /* allocating blocks for indirect blocks and direct blocks */
656                 current_block = ext4_new_meta_blocks(handle, inode,
657                                                         goal, &count, err);
658                 if (*err)
659                         goto failed_out;
660
661                 BUG_ON(current_block + count > EXT4_MAX_BLOCK_FILE_PHYS);
662
663                 target -= count;
664                 /* allocate blocks for indirect blocks */
665                 while (index < indirect_blks && count) {
666                         new_blocks[index++] = current_block++;
667                         count--;
668                 }
669                 if (count > 0) {
670                         /*
671                          * save the new block number
672                          * for the first direct block
673                          */
674                         new_blocks[index] = current_block;
675                         printk(KERN_INFO "%s returned more blocks than "
676                                                 "requested\n", __func__);
677                         WARN_ON(1);
678                         break;
679                 }
680         }
681
682         target = blks - count ;
683         blk_allocated = count;
684         if (!target)
685                 goto allocated;
686         /* Now allocate data blocks */
687         memset(&ar, 0, sizeof(ar));
688         ar.inode = inode;
689         ar.goal = goal;
690         ar.len = target;
691         ar.logical = iblock;
692         if (S_ISREG(inode->i_mode))
693                 /* enable in-core preallocation only for regular files */
694                 ar.flags = EXT4_MB_HINT_DATA;
695
696         current_block = ext4_mb_new_blocks(handle, &ar, err);
697         BUG_ON(current_block + ar.len > EXT4_MAX_BLOCK_FILE_PHYS);
698
699         if (*err && (target == blks)) {
700                 /*
701                  * if the allocation failed and we didn't allocate
702                  * any blocks before
703                  */
704                 goto failed_out;
705         }
706         if (!*err) {
707                 if (target == blks) {
708                         /*
709                          * save the new block number
710                          * for the first direct block
711                          */
712                         new_blocks[index] = current_block;
713                 }
714                 blk_allocated += ar.len;
715         }
716 allocated:
717         /* total number of blocks allocated for direct blocks */
718         ret = blk_allocated;
719         *err = 0;
720         return ret;
721 failed_out:
722         for (i = 0; i < index; i++)
723                 ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
724         return ret;
725 }
726
727 /**
728  *      ext4_alloc_branch - allocate and set up a chain of blocks.
729  *      @inode: owner
730  *      @indirect_blks: number of allocated indirect blocks
731  *      @blks: number of allocated direct blocks
732  *      @offsets: offsets (in the blocks) to store the pointers to next.
733  *      @branch: place to store the chain in.
734  *
735  *      This function allocates blocks, zeroes out all but the last one,
736  *      links them into chain and (if we are synchronous) writes them to disk.
737  *      In other words, it prepares a branch that can be spliced onto the
738  *      inode. It stores the information about that chain in the branch[], in
739  *      the same format as ext4_get_branch() would do. We are calling it after
740  *      we had read the existing part of chain and partial points to the last
741  *      triple of that (one with zero ->key). Upon the exit we have the same
742  *      picture as after the successful ext4_get_block(), except that in one
743  *      place chain is disconnected - *branch->p is still zero (we did not
744  *      set the last link), but branch->key contains the number that should
745  *      be placed into *branch->p to fill that gap.
746  *
747  *      If allocation fails we free all blocks we've allocated (and forget
748  *      their buffer_heads) and return the error value the from failed
749  *      ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
750  *      as described above and return 0.
751  */
752 static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
753                              ext4_lblk_t iblock, int indirect_blks,
754                              int *blks, ext4_fsblk_t goal,
755                              ext4_lblk_t *offsets, Indirect *branch)
756 {
757         int blocksize = inode->i_sb->s_blocksize;
758         int i, n = 0;
759         int err = 0;
760         struct buffer_head *bh;
761         int num;
762         ext4_fsblk_t new_blocks[4];
763         ext4_fsblk_t current_block;
764
765         num = ext4_alloc_blocks(handle, inode, iblock, goal, indirect_blks,
766                                 *blks, new_blocks, &err);
767         if (err)
768                 return err;
769
770         branch[0].key = cpu_to_le32(new_blocks[0]);
771         /*
772          * metadata blocks and data blocks are allocated.
773          */
774         for (n = 1; n <= indirect_blks;  n++) {
775                 /*
776                  * Get buffer_head for parent block, zero it out
777                  * and set the pointer to new one, then send
778                  * parent to disk.
779                  */
780                 bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
781                 branch[n].bh = bh;
782                 lock_buffer(bh);
783                 BUFFER_TRACE(bh, "call get_create_access");
784                 err = ext4_journal_get_create_access(handle, bh);
785                 if (err) {
786                         /* Don't brelse(bh) here; it's done in
787                          * ext4_journal_forget() below */
788                         unlock_buffer(bh);
789                         goto failed;
790                 }
791
792                 memset(bh->b_data, 0, blocksize);
793                 branch[n].p = (__le32 *) bh->b_data + offsets[n];
794                 branch[n].key = cpu_to_le32(new_blocks[n]);
795                 *branch[n].p = branch[n].key;
796                 if (n == indirect_blks) {
797                         current_block = new_blocks[n];
798                         /*
799                          * End of chain, update the last new metablock of
800                          * the chain to point to the new allocated
801                          * data blocks numbers
802                          */
803                         for (i = 1; i < num; i++)
804                                 *(branch[n].p + i) = cpu_to_le32(++current_block);
805                 }
806                 BUFFER_TRACE(bh, "marking uptodate");
807                 set_buffer_uptodate(bh);
808                 unlock_buffer(bh);
809
810                 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
811                 err = ext4_handle_dirty_metadata(handle, inode, bh);
812                 if (err)
813                         goto failed;
814         }
815         *blks = num;
816         return err;
817 failed:
818         /* Allocation failed, free what we already allocated */
819         for (i = 1; i <= n ; i++) {
820                 BUFFER_TRACE(branch[i].bh, "call jbd2_journal_forget");
821                 ext4_journal_forget(handle, branch[i].bh);
822         }
823         for (i = 0; i < indirect_blks; i++)
824                 ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
825
826         ext4_free_blocks(handle, inode, new_blocks[i], num, 0);
827
828         return err;
829 }
830
831 /**
832  * ext4_splice_branch - splice the allocated branch onto inode.
833  * @inode: owner
834  * @block: (logical) number of block we are adding
835  * @chain: chain of indirect blocks (with a missing link - see
836  *      ext4_alloc_branch)
837  * @where: location of missing link
838  * @num:   number of indirect blocks we are adding
839  * @blks:  number of direct blocks we are adding
840  *
841  * This function fills the missing link and does all housekeeping needed in
842  * inode (->i_blocks, etc.). In case of success we end up with the full
843  * chain to new block and return 0.
844  */
845 static int ext4_splice_branch(handle_t *handle, struct inode *inode,
846                               ext4_lblk_t block, Indirect *where, int num,
847                               int blks)
848 {
849         int i;
850         int err = 0;
851         ext4_fsblk_t current_block;
852
853         /*
854          * If we're splicing into a [td]indirect block (as opposed to the
855          * inode) then we need to get write access to the [td]indirect block
856          * before the splice.
857          */
858         if (where->bh) {
859                 BUFFER_TRACE(where->bh, "get_write_access");
860                 err = ext4_journal_get_write_access(handle, where->bh);
861                 if (err)
862                         goto err_out;
863         }
864         /* That's it */
865
866         *where->p = where->key;
867
868         /*
869          * Update the host buffer_head or inode to point to more just allocated
870          * direct blocks blocks
871          */
872         if (num == 0 && blks > 1) {
873                 current_block = le32_to_cpu(where->key) + 1;
874                 for (i = 1; i < blks; i++)
875                         *(where->p + i) = cpu_to_le32(current_block++);
876         }
877
878         /* We are done with atomic stuff, now do the rest of housekeeping */
879         /* had we spliced it onto indirect block? */
880         if (where->bh) {
881                 /*
882                  * If we spliced it onto an indirect block, we haven't
883                  * altered the inode.  Note however that if it is being spliced
884                  * onto an indirect block at the very end of the file (the
885                  * file is growing) then we *will* alter the inode to reflect
886                  * the new i_size.  But that is not done here - it is done in
887                  * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
888                  */
889                 jbd_debug(5, "splicing indirect only\n");
890                 BUFFER_TRACE(where->bh, "call ext4_handle_dirty_metadata");
891                 err = ext4_handle_dirty_metadata(handle, inode, where->bh);
892                 if (err)
893                         goto err_out;
894         } else {
895                 /*
896                  * OK, we spliced it into the inode itself on a direct block.
897                  */
898                 ext4_mark_inode_dirty(handle, inode);
899                 jbd_debug(5, "splicing direct\n");
900         }
901         return err;
902
903 err_out:
904         for (i = 1; i <= num; i++) {
905                 BUFFER_TRACE(where[i].bh, "call jbd2_journal_forget");
906                 ext4_journal_forget(handle, where[i].bh);
907                 ext4_free_blocks(handle, inode,
908                                         le32_to_cpu(where[i-1].key), 1, 0);
909         }
910         ext4_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks, 0);
911
912         return err;
913 }
914
915 /*
916  * The ext4_ind_get_blocks() function handles non-extents inodes
917  * (i.e., using the traditional indirect/double-indirect i_blocks
918  * scheme) for ext4_get_blocks().
919  *
920  * Allocation strategy is simple: if we have to allocate something, we will
921  * have to go the whole way to leaf. So let's do it before attaching anything
922  * to tree, set linkage between the newborn blocks, write them if sync is
923  * required, recheck the path, free and repeat if check fails, otherwise
924  * set the last missing link (that will protect us from any truncate-generated
925  * removals - all blocks on the path are immune now) and possibly force the
926  * write on the parent block.
927  * That has a nice additional property: no special recovery from the failed
928  * allocations is needed - we simply release blocks and do not touch anything
929  * reachable from inode.
930  *
931  * `handle' can be NULL if create == 0.
932  *
933  * return > 0, # of blocks mapped or allocated.
934  * return = 0, if plain lookup failed.
935  * return < 0, error case.
936  *
937  * The ext4_ind_get_blocks() function should be called with
938  * down_write(&EXT4_I(inode)->i_data_sem) if allocating filesystem
939  * blocks (i.e., flags has EXT4_GET_BLOCKS_CREATE set) or
940  * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system
941  * blocks.
942  */
943 static int ext4_ind_get_blocks(handle_t *handle, struct inode *inode,
944                                ext4_lblk_t iblock, unsigned int maxblocks,
945                                struct buffer_head *bh_result,
946                                int flags)
947 {
948         int err = -EIO;
949         ext4_lblk_t offsets[4];
950         Indirect chain[4];
951         Indirect *partial;
952         ext4_fsblk_t goal;
953         int indirect_blks;
954         int blocks_to_boundary = 0;
955         int depth;
956         int count = 0;
957         ext4_fsblk_t first_block = 0;
958
959         J_ASSERT(!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL));
960         J_ASSERT(handle != NULL || (flags & EXT4_GET_BLOCKS_CREATE) == 0);
961         depth = ext4_block_to_path(inode, iblock, offsets,
962                                    &blocks_to_boundary);
963
964         if (depth == 0)
965                 goto out;
966
967         partial = ext4_get_branch(inode, depth, offsets, chain, &err);
968
969         /* Simplest case - block found, no allocation needed */
970         if (!partial) {
971                 first_block = le32_to_cpu(chain[depth - 1].key);
972                 clear_buffer_new(bh_result);
973                 count++;
974                 /*map more blocks*/
975                 while (count < maxblocks && count <= blocks_to_boundary) {
976                         ext4_fsblk_t blk;
977
978                         blk = le32_to_cpu(*(chain[depth-1].p + count));
979
980                         if (blk == first_block + count)
981                                 count++;
982                         else
983                                 break;
984                 }
985                 goto got_it;
986         }
987
988         /* Next simple case - plain lookup or failed read of indirect block */
989         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0 || err == -EIO)
990                 goto cleanup;
991
992         /*
993          * Okay, we need to do block allocation.
994         */
995         goal = ext4_find_goal(inode, iblock, partial);
996
997         /* the number of blocks need to allocate for [d,t]indirect blocks */
998         indirect_blks = (chain + depth) - partial - 1;
999
1000         /*
1001          * Next look up the indirect map to count the totoal number of
1002          * direct blocks to allocate for this branch.
1003          */
1004         count = ext4_blks_to_allocate(partial, indirect_blks,
1005                                         maxblocks, blocks_to_boundary);
1006         /*
1007          * Block out ext4_truncate while we alter the tree
1008          */
1009         err = ext4_alloc_branch(handle, inode, iblock, indirect_blks,
1010                                 &count, goal,
1011                                 offsets + (partial - chain), partial);
1012
1013         /*
1014          * The ext4_splice_branch call will free and forget any buffers
1015          * on the new chain if there is a failure, but that risks using
1016          * up transaction credits, especially for bitmaps where the
1017          * credits cannot be returned.  Can we handle this somehow?  We
1018          * may need to return -EAGAIN upwards in the worst case.  --sct
1019          */
1020         if (!err)
1021                 err = ext4_splice_branch(handle, inode, iblock,
1022                                          partial, indirect_blks, count);
1023         else
1024                 goto cleanup;
1025
1026         set_buffer_new(bh_result);
1027 got_it:
1028         map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
1029         if (count > blocks_to_boundary)
1030                 set_buffer_boundary(bh_result);
1031         err = count;
1032         /* Clean up and exit */
1033         partial = chain + depth - 1;    /* the whole chain */
1034 cleanup:
1035         while (partial > chain) {
1036                 BUFFER_TRACE(partial->bh, "call brelse");
1037                 brelse(partial->bh);
1038                 partial--;
1039         }
1040         BUFFER_TRACE(bh_result, "returned");
1041 out:
1042         return err;
1043 }
1044
1045 qsize_t ext4_get_reserved_space(struct inode *inode)
1046 {
1047         unsigned long long total;
1048
1049         spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1050         total = EXT4_I(inode)->i_reserved_data_blocks +
1051                 EXT4_I(inode)->i_reserved_meta_blocks;
1052         spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1053
1054         return total;
1055 }
1056 /*
1057  * Calculate the number of metadata blocks need to reserve
1058  * to allocate @blocks for non extent file based file
1059  */
1060 static int ext4_indirect_calc_metadata_amount(struct inode *inode, int blocks)
1061 {
1062         int icap = EXT4_ADDR_PER_BLOCK(inode->i_sb);
1063         int ind_blks, dind_blks, tind_blks;
1064
1065         /* number of new indirect blocks needed */
1066         ind_blks = (blocks + icap - 1) / icap;
1067
1068         dind_blks = (ind_blks + icap - 1) / icap;
1069
1070         tind_blks = 1;
1071
1072         return ind_blks + dind_blks + tind_blks;
1073 }
1074
1075 /*
1076  * Calculate the number of metadata blocks need to reserve
1077  * to allocate given number of blocks
1078  */
1079 static int ext4_calc_metadata_amount(struct inode *inode, int blocks)
1080 {
1081         if (!blocks)
1082                 return 0;
1083
1084         if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
1085                 return ext4_ext_calc_metadata_amount(inode, blocks);
1086
1087         return ext4_indirect_calc_metadata_amount(inode, blocks);
1088 }
1089
1090 static void ext4_da_update_reserve_space(struct inode *inode, int used)
1091 {
1092         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1093         int total, mdb, mdb_free;
1094
1095         spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1096         /* recalculate the number of metablocks still need to be reserved */
1097         total = EXT4_I(inode)->i_reserved_data_blocks - used;
1098         mdb = ext4_calc_metadata_amount(inode, total);
1099
1100         /* figure out how many metablocks to release */
1101         BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
1102         mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;
1103
1104         if (mdb_free) {
1105                 /* Account for allocated meta_blocks */
1106                 mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks;
1107
1108                 /* update fs dirty blocks counter */
1109                 percpu_counter_sub(&sbi->s_dirtyblocks_counter, mdb_free);
1110                 EXT4_I(inode)->i_allocated_meta_blocks = 0;
1111                 EXT4_I(inode)->i_reserved_meta_blocks = mdb;
1112         }
1113
1114         /* update per-inode reservations */
1115         BUG_ON(used  > EXT4_I(inode)->i_reserved_data_blocks);
1116         EXT4_I(inode)->i_reserved_data_blocks -= used;
1117         spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1118
1119         /*
1120          * free those over-booking quota for metadata blocks
1121          */
1122         if (mdb_free)
1123                 vfs_dq_release_reservation_block(inode, mdb_free);
1124
1125         /*
1126          * If we have done all the pending block allocations and if
1127          * there aren't any writers on the inode, we can discard the
1128          * inode's preallocations.
1129          */
1130         if (!total && (atomic_read(&inode->i_writecount) == 0))
1131                 ext4_discard_preallocations(inode);
1132 }
1133
1134 static int check_block_validity(struct inode *inode, const char *msg,
1135                                 sector_t logical, sector_t phys, int len)
1136 {
1137         if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), phys, len)) {
1138                 ext4_error(inode->i_sb, msg,
1139                            "inode #%lu logical block %llu mapped to %llu "
1140                            "(size %d)", inode->i_ino,
1141                            (unsigned long long) logical,
1142                            (unsigned long long) phys, len);
1143                 return -EIO;
1144         }
1145         return 0;
1146 }
1147
1148 /*
1149  * Return the number of dirty pages in the given inode starting at
1150  * page frame idx.
1151  */
1152 static pgoff_t ext4_num_dirty_pages(struct inode *inode, pgoff_t idx,
1153                                     unsigned int max_pages)
1154 {
1155         struct address_space *mapping = inode->i_mapping;
1156         pgoff_t index;
1157         struct pagevec pvec;
1158         pgoff_t num = 0;
1159         int i, nr_pages, done = 0;
1160
1161         if (max_pages == 0)
1162                 return 0;
1163         pagevec_init(&pvec, 0);
1164         while (!done) {
1165                 index = idx;
1166                 nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
1167                                               PAGECACHE_TAG_DIRTY,
1168                                               (pgoff_t)PAGEVEC_SIZE);
1169                 if (nr_pages == 0)
1170                         break;
1171                 for (i = 0; i < nr_pages; i++) {
1172                         struct page *page = pvec.pages[i];
1173                         struct buffer_head *bh, *head;
1174
1175                         lock_page(page);
1176                         if (unlikely(page->mapping != mapping) ||
1177                             !PageDirty(page) ||
1178                             PageWriteback(page) ||
1179                             page->index != idx) {
1180                                 done = 1;
1181                                 unlock_page(page);
1182                                 break;
1183                         }
1184                         head = page_buffers(page);
1185                         bh = head;
1186                         do {
1187                                 if (!buffer_delay(bh) &&
1188                                     !buffer_unwritten(bh)) {
1189                                         done = 1;
1190                                         break;
1191                                 }
1192                         } while ((bh = bh->b_this_page) != head);
1193                         unlock_page(page);
1194                         if (done)
1195                                 break;
1196                         idx++;
1197                         num++;
1198                         if (num >= max_pages)
1199                                 break;
1200                 }
1201                 pagevec_release(&pvec);
1202         }
1203         return num;
1204 }
1205
1206 /*
1207  * The ext4_get_blocks() function tries to look up the requested blocks,
1208  * and returns if the blocks are already mapped.
1209  *
1210  * Otherwise it takes the write lock of the i_data_sem and allocate blocks
1211  * and store the allocated blocks in the result buffer head and mark it
1212  * mapped.
1213  *
1214  * If file type is extents based, it will call ext4_ext_get_blocks(),
1215  * Otherwise, call with ext4_ind_get_blocks() to handle indirect mapping
1216  * based files
1217  *
1218  * On success, it returns the number of blocks being mapped or allocate.
1219  * if create==0 and the blocks are pre-allocated and uninitialized block,
1220  * the result buffer head is unmapped. If the create ==1, it will make sure
1221  * the buffer head is mapped.
1222  *
1223  * It returns 0 if plain look up failed (blocks have not been allocated), in
1224  * that casem, buffer head is unmapped
1225  *
1226  * It returns the error in case of allocation failure.
1227  */
1228 int ext4_get_blocks(handle_t *handle, struct inode *inode, sector_t block,
1229                     unsigned int max_blocks, struct buffer_head *bh,
1230                     int flags)
1231 {
1232         int retval;
1233
1234         clear_buffer_mapped(bh);
1235         clear_buffer_unwritten(bh);
1236
1237         ext_debug("ext4_get_blocks(): inode %lu, flag %d, max_blocks %u,"
1238                   "logical block %lu\n", inode->i_ino, flags, max_blocks,
1239                   (unsigned long)block);
1240         /*
1241          * Try to see if we can get the block without requesting a new
1242          * file system block.
1243          */
1244         down_read((&EXT4_I(inode)->i_data_sem));
1245         if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
1246                 retval =  ext4_ext_get_blocks(handle, inode, block, max_blocks,
1247                                 bh, 0);
1248         } else {
1249                 retval = ext4_ind_get_blocks(handle, inode, block, max_blocks,
1250                                              bh, 0);
1251         }
1252         up_read((&EXT4_I(inode)->i_data_sem));
1253
1254         if (retval > 0 && buffer_mapped(bh)) {
1255                 int ret = check_block_validity(inode, "file system corruption",
1256                                                block, bh->b_blocknr, retval);
1257                 if (ret != 0)
1258                         return ret;
1259         }
1260
1261         /* If it is only a block(s) look up */
1262         if ((flags & EXT4_GET_BLOCKS_CREATE) == 0)
1263                 return retval;
1264
1265         /*
1266          * Returns if the blocks have already allocated
1267          *
1268          * Note that if blocks have been preallocated
1269          * ext4_ext_get_block() returns th create = 0
1270          * with buffer head unmapped.
1271          */
1272         if (retval > 0 && buffer_mapped(bh))
1273                 return retval;
1274
1275         /*
1276          * When we call get_blocks without the create flag, the
1277          * BH_Unwritten flag could have gotten set if the blocks
1278          * requested were part of a uninitialized extent.  We need to
1279          * clear this flag now that we are committed to convert all or
1280          * part of the uninitialized extent to be an initialized
1281          * extent.  This is because we need to avoid the combination
1282          * of BH_Unwritten and BH_Mapped flags being simultaneously
1283          * set on the buffer_head.
1284          */
1285         clear_buffer_unwritten(bh);
1286
1287         /*
1288          * New blocks allocate and/or writing to uninitialized extent
1289          * will possibly result in updating i_data, so we take
1290          * the write lock of i_data_sem, and call get_blocks()
1291          * with create == 1 flag.
1292          */
1293         down_write((&EXT4_I(inode)->i_data_sem));
1294
1295         /*
1296          * if the caller is from delayed allocation writeout path
1297          * we have already reserved fs blocks for allocation
1298          * let the underlying get_block() function know to
1299          * avoid double accounting
1300          */
1301         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1302                 EXT4_I(inode)->i_delalloc_reserved_flag = 1;
1303         /*
1304          * We need to check for EXT4 here because migrate
1305          * could have changed the inode type in between
1306          */
1307         if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
1308                 retval =  ext4_ext_get_blocks(handle, inode, block, max_blocks,
1309                                               bh, flags);
1310         } else {
1311                 retval = ext4_ind_get_blocks(handle, inode, block,
1312                                              max_blocks, bh, flags);
1313
1314                 if (retval > 0 && buffer_new(bh)) {
1315                         /*
1316                          * We allocated new blocks which will result in
1317                          * i_data's format changing.  Force the migrate
1318                          * to fail by clearing migrate flags
1319                          */
1320                         EXT4_I(inode)->i_state &= ~EXT4_STATE_EXT_MIGRATE;
1321                 }
1322         }
1323
1324         if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
1325                 EXT4_I(inode)->i_delalloc_reserved_flag = 0;
1326
1327         /*
1328          * Update reserved blocks/metadata blocks after successful
1329          * block allocation which had been deferred till now.
1330          */
1331         if ((retval > 0) && (flags & EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE))
1332                 ext4_da_update_reserve_space(inode, retval);
1333
1334         up_write((&EXT4_I(inode)->i_data_sem));
1335         if (retval > 0 && buffer_mapped(bh)) {
1336                 int ret = check_block_validity(inode, "file system "
1337                                                "corruption after allocation",
1338                                                block, bh->b_blocknr, retval);
1339                 if (ret != 0)
1340                         return ret;
1341         }
1342         return retval;
1343 }
1344
1345 /* Maximum number of blocks we map for direct IO at once. */
1346 #define DIO_MAX_BLOCKS 4096
1347
1348 int ext4_get_block(struct inode *inode, sector_t iblock,
1349                    struct buffer_head *bh_result, int create)
1350 {
1351         handle_t *handle = ext4_journal_current_handle();
1352         int ret = 0, started = 0;
1353         unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
1354         int dio_credits;
1355
1356         if (create && !handle) {
1357                 /* Direct IO write... */
1358                 if (max_blocks > DIO_MAX_BLOCKS)
1359                         max_blocks = DIO_MAX_BLOCKS;
1360                 dio_credits = ext4_chunk_trans_blocks(inode, max_blocks);
1361                 handle = ext4_journal_start(inode, dio_credits);
1362                 if (IS_ERR(handle)) {
1363                         ret = PTR_ERR(handle);
1364                         goto out;
1365                 }
1366                 started = 1;
1367         }
1368
1369         ret = ext4_get_blocks(handle, inode, iblock, max_blocks, bh_result,
1370                               create ? EXT4_GET_BLOCKS_CREATE : 0);
1371         if (ret > 0) {
1372                 bh_result->b_size = (ret << inode->i_blkbits);
1373                 ret = 0;
1374         }
1375         if (started)
1376                 ext4_journal_stop(handle);
1377 out:
1378         return ret;
1379 }
1380
1381 /*
1382  * `handle' can be NULL if create is zero
1383  */
1384 struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
1385                                 ext4_lblk_t block, int create, int *errp)
1386 {
1387         struct buffer_head dummy;
1388         int fatal = 0, err;
1389         int flags = 0;
1390
1391         J_ASSERT(handle != NULL || create == 0);
1392
1393         dummy.b_state = 0;
1394         dummy.b_blocknr = -1000;
1395         buffer_trace_init(&dummy.b_history);
1396         if (create)
1397                 flags |= EXT4_GET_BLOCKS_CREATE;
1398         err = ext4_get_blocks(handle, inode, block, 1, &dummy, flags);
1399         /*
1400          * ext4_get_blocks() returns number of blocks mapped. 0 in
1401          * case of a HOLE.
1402          */
1403         if (err > 0) {
1404                 if (err > 1)
1405                         WARN_ON(1);
1406                 err = 0;
1407         }
1408         *errp = err;
1409         if (!err && buffer_mapped(&dummy)) {
1410                 struct buffer_head *bh;
1411                 bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
1412                 if (!bh) {
1413                         *errp = -EIO;
1414                         goto err;
1415                 }
1416                 if (buffer_new(&dummy)) {
1417                         J_ASSERT(create != 0);
1418                         J_ASSERT(handle != NULL);
1419
1420                         /*
1421                          * Now that we do not always journal data, we should
1422                          * keep in mind whether this should always journal the
1423                          * new buffer as metadata.  For now, regular file
1424                          * writes use ext4_get_block instead, so it's not a
1425                          * problem.
1426                          */
1427                         lock_buffer(bh);
1428                         BUFFER_TRACE(bh, "call get_create_access");
1429                         fatal = ext4_journal_get_create_access(handle, bh);
1430                         if (!fatal && !buffer_uptodate(bh)) {
1431                                 memset(bh->b_data, 0, inode->i_sb->s_blocksize);
1432                                 set_buffer_uptodate(bh);
1433                         }
1434                         unlock_buffer(bh);
1435                         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
1436                         err = ext4_handle_dirty_metadata(handle, inode, bh);
1437                         if (!fatal)
1438                                 fatal = err;
1439                 } else {
1440                         BUFFER_TRACE(bh, "not a new buffer");
1441                 }
1442                 if (fatal) {
1443                         *errp = fatal;
1444                         brelse(bh);
1445                         bh = NULL;
1446                 }
1447                 return bh;
1448         }
1449 err:
1450         return NULL;
1451 }
1452
1453 struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
1454                                ext4_lblk_t block, int create, int *err)
1455 {
1456         struct buffer_head *bh;
1457
1458         bh = ext4_getblk(handle, inode, block, create, err);
1459         if (!bh)
1460                 return bh;
1461         if (buffer_uptodate(bh))
1462                 return bh;
1463         ll_rw_block(READ_META, 1, &bh);
1464         wait_on_buffer(bh);
1465         if (buffer_uptodate(bh))
1466                 return bh;
1467         put_bh(bh);
1468         *err = -EIO;
1469         return NULL;
1470 }
1471
1472 static int walk_page_buffers(handle_t *handle,
1473                              struct buffer_head *head,
1474                              unsigned from,
1475                              unsigned to,
1476                              int *partial,
1477                              int (*fn)(handle_t *handle,
1478                                        struct buffer_head *bh))
1479 {
1480         struct buffer_head *bh;
1481         unsigned block_start, block_end;
1482         unsigned blocksize = head->b_size;
1483         int err, ret = 0;
1484         struct buffer_head *next;
1485
1486         for (bh = head, block_start = 0;
1487              ret == 0 && (bh != head || !block_start);
1488              block_start = block_end, bh = next) {
1489                 next = bh->b_this_page;
1490                 block_end = block_start + blocksize;
1491                 if (block_end <= from || block_start >= to) {
1492                         if (partial && !buffer_uptodate(bh))
1493                                 *partial = 1;
1494                         continue;
1495                 }
1496                 err = (*fn)(handle, bh);
1497                 if (!ret)
1498                         ret = err;
1499         }
1500         return ret;
1501 }
1502
1503 /*
1504  * To preserve ordering, it is essential that the hole instantiation and
1505  * the data write be encapsulated in a single transaction.  We cannot
1506  * close off a transaction and start a new one between the ext4_get_block()
1507  * and the commit_write().  So doing the jbd2_journal_start at the start of
1508  * prepare_write() is the right place.
1509  *
1510  * Also, this function can nest inside ext4_writepage() ->
1511  * block_write_full_page(). In that case, we *know* that ext4_writepage()
1512  * has generated enough buffer credits to do the whole page.  So we won't
1513  * block on the journal in that case, which is good, because the caller may
1514  * be PF_MEMALLOC.
1515  *
1516  * By accident, ext4 can be reentered when a transaction is open via
1517  * quota file writes.  If we were to commit the transaction while thus
1518  * reentered, there can be a deadlock - we would be holding a quota
1519  * lock, and the commit would never complete if another thread had a
1520  * transaction open and was blocking on the quota lock - a ranking
1521  * violation.
1522  *
1523  * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
1524  * will _not_ run commit under these circumstances because handle->h_ref
1525  * is elevated.  We'll still have enough credits for the tiny quotafile
1526  * write.
1527  */
1528 static int do_journal_get_write_access(handle_t *handle,
1529                                        struct buffer_head *bh)
1530 {
1531         if (!buffer_mapped(bh) || buffer_freed(bh))
1532                 return 0;
1533         return ext4_journal_get_write_access(handle, bh);
1534 }
1535
1536 static int ext4_write_begin(struct file *file, struct address_space *mapping,
1537                             loff_t pos, unsigned len, unsigned flags,
1538                             struct page **pagep, void **fsdata)
1539 {
1540         struct inode *inode = mapping->host;
1541         int ret, needed_blocks;
1542         handle_t *handle;
1543         int retries = 0;
1544         struct page *page;
1545         pgoff_t index;
1546         unsigned from, to;
1547
1548         trace_ext4_write_begin(inode, pos, len, flags);
1549         /*
1550          * Reserve one block more for addition to orphan list in case
1551          * we allocate blocks but write fails for some reason
1552          */
1553         needed_blocks = ext4_writepage_trans_blocks(inode) + 1;
1554         index = pos >> PAGE_CACHE_SHIFT;
1555         from = pos & (PAGE_CACHE_SIZE - 1);
1556         to = from + len;
1557
1558 retry:
1559         handle = ext4_journal_start(inode, needed_blocks);
1560         if (IS_ERR(handle)) {
1561                 ret = PTR_ERR(handle);
1562                 goto out;
1563         }
1564
1565         /* We cannot recurse into the filesystem as the transaction is already
1566          * started */
1567         flags |= AOP_FLAG_NOFS;
1568
1569         page = grab_cache_page_write_begin(mapping, index, flags);
1570         if (!page) {
1571                 ext4_journal_stop(handle);
1572                 ret = -ENOMEM;
1573                 goto out;
1574         }
1575         *pagep = page;
1576
1577         ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
1578                                 ext4_get_block);
1579
1580         if (!ret && ext4_should_journal_data(inode)) {
1581                 ret = walk_page_buffers(handle, page_buffers(page),
1582                                 from, to, NULL, do_journal_get_write_access);
1583         }
1584
1585         if (ret) {
1586                 unlock_page(page);
1587                 page_cache_release(page);
1588                 /*
1589                  * block_write_begin may have instantiated a few blocks
1590                  * outside i_size.  Trim these off again. Don't need
1591                  * i_size_read because we hold i_mutex.
1592                  *
1593                  * Add inode to orphan list in case we crash before
1594                  * truncate finishes
1595                  */
1596                 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1597                         ext4_orphan_add(handle, inode);
1598
1599                 ext4_journal_stop(handle);
1600                 if (pos + len > inode->i_size) {
1601                         ext4_truncate(inode);
1602                         /*
1603                          * If truncate failed early the inode might
1604                          * still be on the orphan list; we need to
1605                          * make sure the inode is removed from the
1606                          * orphan list in that case.
1607                          */
1608                         if (inode->i_nlink)
1609                                 ext4_orphan_del(NULL, inode);
1610                 }
1611         }
1612
1613         if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
1614                 goto retry;
1615 out:
1616         return ret;
1617 }
1618
1619 /* For write_end() in data=journal mode */
1620 static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1621 {
1622         if (!buffer_mapped(bh) || buffer_freed(bh))
1623                 return 0;
1624         set_buffer_uptodate(bh);
1625         return ext4_handle_dirty_metadata(handle, NULL, bh);
1626 }
1627
1628 static int ext4_generic_write_end(struct file *file,
1629                                   struct address_space *mapping,
1630                                   loff_t pos, unsigned len, unsigned copied,
1631                                   struct page *page, void *fsdata)
1632 {
1633         int i_size_changed = 0;
1634         struct inode *inode = mapping->host;
1635         handle_t *handle = ext4_journal_current_handle();
1636
1637         copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
1638
1639         /*
1640          * No need to use i_size_read() here, the i_size
1641          * cannot change under us because we hold i_mutex.
1642          *
1643          * But it's important to update i_size while still holding page lock:
1644          * page writeout could otherwise come in and zero beyond i_size.
1645          */
1646         if (pos + copied > inode->i_size) {
1647                 i_size_write(inode, pos + copied);
1648                 i_size_changed = 1;
1649         }
1650
1651         if (pos + copied >  EXT4_I(inode)->i_disksize) {
1652                 /* We need to mark inode dirty even if
1653                  * new_i_size is less that inode->i_size
1654                  * bu greater than i_disksize.(hint delalloc)
1655                  */
1656                 ext4_update_i_disksize(inode, (pos + copied));
1657                 i_size_changed = 1;
1658         }
1659         unlock_page(page);
1660         page_cache_release(page);
1661
1662         /*
1663          * Don't mark the inode dirty under page lock. First, it unnecessarily
1664          * makes the holding time of page lock longer. Second, it forces lock
1665          * ordering of page lock and transaction start for journaling
1666          * filesystems.
1667          */
1668         if (i_size_changed)
1669                 ext4_mark_inode_dirty(handle, inode);
1670
1671         return copied;
1672 }
1673
1674 /*
1675  * We need to pick up the new inode size which generic_commit_write gave us
1676  * `file' can be NULL - eg, when called from page_symlink().
1677  *
1678  * ext4 never places buffers on inode->i_mapping->private_list.  metadata
1679  * buffers are managed internally.
1680  */
1681 static int ext4_ordered_write_end(struct file *file,
1682                                   struct address_space *mapping,
1683                                   loff_t pos, unsigned len, unsigned copied,
1684                                   struct page *page, void *fsdata)
1685 {
1686         handle_t *handle = ext4_journal_current_handle();
1687         struct inode *inode = mapping->host;
1688         int ret = 0, ret2;
1689
1690         trace_ext4_ordered_write_end(inode, pos, len, copied);
1691         ret = ext4_jbd2_file_inode(handle, inode);
1692
1693         if (ret == 0) {
1694                 ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
1695                                                         page, fsdata);
1696                 copied = ret2;
1697                 if (pos + len > inode->i_size && ext4_can_truncate(inode))
1698                         /* if we have allocated more blocks and copied
1699                          * less. We will have blocks allocated outside
1700                          * inode->i_size. So truncate them
1701                          */
1702                         ext4_orphan_add(handle, inode);
1703                 if (ret2 < 0)
1704                         ret = ret2;
1705         }
1706         ret2 = ext4_journal_stop(handle);
1707         if (!ret)
1708                 ret = ret2;
1709
1710         if (pos + len > inode->i_size) {
1711                 ext4_truncate(inode);
1712                 /*
1713                  * If truncate failed early the inode might still be
1714                  * on the orphan list; we need to make sure the inode
1715                  * is removed from the orphan list in that case.
1716                  */
1717                 if (inode->i_nlink)
1718                         ext4_orphan_del(NULL, inode);
1719         }
1720
1721
1722         return ret ? ret : copied;
1723 }
1724
1725 static int ext4_writeback_write_end(struct file *file,
1726                                     struct address_space *mapping,
1727                                     loff_t pos, unsigned len, unsigned copied,
1728                                     struct page *page, void *fsdata)
1729 {
1730         handle_t *handle = ext4_journal_current_handle();
1731         struct inode *inode = mapping->host;
1732         int ret = 0, ret2;
1733
1734         trace_ext4_writeback_write_end(inode, pos, len, copied);
1735         ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
1736                                                         page, fsdata);
1737         copied = ret2;
1738         if (pos + len > inode->i_size && ext4_can_truncate(inode))
1739                 /* if we have allocated more blocks and copied
1740                  * less. We will have blocks allocated outside
1741                  * inode->i_size. So truncate them
1742                  */
1743                 ext4_orphan_add(handle, inode);
1744
1745         if (ret2 < 0)
1746                 ret = ret2;
1747
1748         ret2 = ext4_journal_stop(handle);
1749         if (!ret)
1750                 ret = ret2;
1751
1752         if (pos + len > inode->i_size) {
1753                 ext4_truncate(inode);
1754                 /*
1755                  * If truncate failed early the inode might still be
1756                  * on the orphan list; we need to make sure the inode
1757                  * is removed from the orphan list in that case.
1758                  */
1759                 if (inode->i_nlink)
1760                         ext4_orphan_del(NULL, inode);
1761         }
1762
1763         return ret ? ret : copied;
1764 }
1765
1766 static int ext4_journalled_write_end(struct file *file,
1767                                      struct address_space *mapping,
1768                                      loff_t pos, unsigned len, unsigned copied,
1769                                      struct page *page, void *fsdata)
1770 {
1771         handle_t *handle = ext4_journal_current_handle();
1772         struct inode *inode = mapping->host;
1773         int ret = 0, ret2;
1774         int partial = 0;
1775         unsigned from, to;
1776         loff_t new_i_size;
1777
1778         trace_ext4_journalled_write_end(inode, pos, len, copied);
1779         from = pos & (PAGE_CACHE_SIZE - 1);
1780         to = from + len;
1781
1782         if (copied < len) {
1783                 if (!PageUptodate(page))
1784                         copied = 0;
1785                 page_zero_new_buffers(page, from+copied, to);
1786         }
1787
1788         ret = walk_page_buffers(handle, page_buffers(page), from,
1789                                 to, &partial, write_end_fn);
1790         if (!partial)
1791                 SetPageUptodate(page);
1792         new_i_size = pos + copied;
1793         if (new_i_size > inode->i_size)
1794                 i_size_write(inode, pos+copied);
1795         EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
1796         if (new_i_size > EXT4_I(inode)->i_disksize) {
1797                 ext4_update_i_disksize(inode, new_i_size);
1798                 ret2 = ext4_mark_inode_dirty(handle, inode);
1799                 if (!ret)
1800                         ret = ret2;
1801         }
1802
1803         unlock_page(page);
1804         page_cache_release(page);
1805         if (pos + len > inode->i_size && ext4_can_truncate(inode))
1806                 /* if we have allocated more blocks and copied
1807                  * less. We will have blocks allocated outside
1808                  * inode->i_size. So truncate them
1809                  */
1810                 ext4_orphan_add(handle, inode);
1811
1812         ret2 = ext4_journal_stop(handle);
1813         if (!ret)
1814                 ret = ret2;
1815         if (pos + len > inode->i_size) {
1816                 ext4_truncate(inode);
1817                 /*
1818                  * If truncate failed early the inode might still be
1819                  * on the orphan list; we need to make sure the inode
1820                  * is removed from the orphan list in that case.
1821                  */
1822                 if (inode->i_nlink)
1823                         ext4_orphan_del(NULL, inode);
1824         }
1825
1826         return ret ? ret : copied;
1827 }
1828
1829 static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
1830 {
1831         int retries = 0;
1832         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1833         unsigned long md_needed, mdblocks, total = 0;
1834
1835         /*
1836          * recalculate the amount of metadata blocks to reserve
1837          * in order to allocate nrblocks
1838          * worse case is one extent per block
1839          */
1840 repeat:
1841         spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1842         total = EXT4_I(inode)->i_reserved_data_blocks + nrblocks;
1843         mdblocks = ext4_calc_metadata_amount(inode, total);
1844         BUG_ON(mdblocks < EXT4_I(inode)->i_reserved_meta_blocks);
1845
1846         md_needed = mdblocks - EXT4_I(inode)->i_reserved_meta_blocks;
1847         total = md_needed + nrblocks;
1848
1849         /*
1850          * Make quota reservation here to prevent quota overflow
1851          * later. Real quota accounting is done at pages writeout
1852          * time.
1853          */
1854         if (vfs_dq_reserve_block(inode, total)) {
1855                 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1856                 return -EDQUOT;
1857         }
1858
1859         if (ext4_claim_free_blocks(sbi, total)) {
1860                 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1861                 vfs_dq_release_reservation_block(inode, total);
1862                 if (ext4_should_retry_alloc(inode->i_sb, &retries)) {
1863                         yield();
1864                         goto repeat;
1865                 }
1866                 return -ENOSPC;
1867         }
1868         EXT4_I(inode)->i_reserved_data_blocks += nrblocks;
1869         EXT4_I(inode)->i_reserved_meta_blocks = mdblocks;
1870
1871         spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1872         return 0;       /* success */
1873 }
1874
1875 static void ext4_da_release_space(struct inode *inode, int to_free)
1876 {
1877         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1878         int total, mdb, mdb_free, release;
1879
1880         if (!to_free)
1881                 return;         /* Nothing to release, exit */
1882
1883         spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1884
1885         if (!EXT4_I(inode)->i_reserved_data_blocks) {
1886                 /*
1887                  * if there is no reserved blocks, but we try to free some
1888                  * then the counter is messed up somewhere.
1889                  * but since this function is called from invalidate
1890                  * page, it's harmless to return without any action
1891                  */
1892                 printk(KERN_INFO "ext4 delalloc try to release %d reserved "
1893                             "blocks for inode %lu, but there is no reserved "
1894                             "data blocks\n", to_free, inode->i_ino);
1895                 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1896                 return;
1897         }
1898
1899         /* recalculate the number of metablocks still need to be reserved */
1900         total = EXT4_I(inode)->i_reserved_data_blocks - to_free;
1901         mdb = ext4_calc_metadata_amount(inode, total);
1902
1903         /* figure out how many metablocks to release */
1904         BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
1905         mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;
1906
1907         release = to_free + mdb_free;
1908
1909         /* update fs dirty blocks counter for truncate case */
1910         percpu_counter_sub(&sbi->s_dirtyblocks_counter, release);
1911
1912         /* update per-inode reservations */
1913         BUG_ON(to_free > EXT4_I(inode)->i_reserved_data_blocks);
1914         EXT4_I(inode)->i_reserved_data_blocks -= to_free;
1915
1916         BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
1917         EXT4_I(inode)->i_reserved_meta_blocks = mdb;
1918         spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1919
1920         vfs_dq_release_reservation_block(inode, release);
1921 }
1922
1923 static void ext4_da_page_release_reservation(struct page *page,
1924                                              unsigned long offset)
1925 {
1926         int to_release = 0;
1927         struct buffer_head *head, *bh;
1928         unsigned int curr_off = 0;
1929
1930         head = page_buffers(page);
1931         bh = head;
1932         do {
1933                 unsigned int next_off = curr_off + bh->b_size;
1934
1935                 if ((offset <= curr_off) && (buffer_delay(bh))) {
1936                         to_release++;
1937                         clear_buffer_delay(bh);
1938                 }
1939                 curr_off = next_off;
1940         } while ((bh = bh->b_this_page) != head);
1941         ext4_da_release_space(page->mapping->host, to_release);
1942 }
1943
1944 /*
1945  * Delayed allocation stuff
1946  */
1947
1948 /*
1949  * mpage_da_submit_io - walks through extent of pages and try to write
1950  * them with writepage() call back
1951  *
1952  * @mpd->inode: inode
1953  * @mpd->first_page: first page of the extent
1954  * @mpd->next_page: page after the last page of the extent
1955  *
1956  * By the time mpage_da_submit_io() is called we expect all blocks
1957  * to be allocated. this may be wrong if allocation failed.
1958  *
1959  * As pages are already locked by write_cache_pages(), we can't use it
1960  */
1961 static int mpage_da_submit_io(struct mpage_da_data *mpd)
1962 {
1963         long pages_skipped;
1964         struct pagevec pvec;
1965         unsigned long index, end;
1966         int ret = 0, err, nr_pages, i;
1967         struct inode *inode = mpd->inode;
1968         struct address_space *mapping = inode->i_mapping;
1969
1970         BUG_ON(mpd->next_page <= mpd->first_page);
1971         /*
1972          * We need to start from the first_page to the next_page - 1
1973          * to make sure we also write the mapped dirty buffer_heads.
1974          * If we look at mpd->b_blocknr we would only be looking
1975          * at the currently mapped buffer_heads.
1976          */
1977         index = mpd->first_page;
1978         end = mpd->next_page - 1;
1979
1980         pagevec_init(&pvec, 0);
1981         while (index <= end) {
1982                 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
1983                 if (nr_pages == 0)
1984                         break;
1985                 for (i = 0; i < nr_pages; i++) {
1986                         struct page *page = pvec.pages[i];
1987
1988                         index = page->index;
1989                         if (index > end)
1990                                 break;
1991                         index++;
1992
1993                         BUG_ON(!PageLocked(page));
1994                         BUG_ON(PageWriteback(page));
1995
1996                         pages_skipped = mpd->wbc->pages_skipped;
1997                         err = mapping->a_ops->writepage(page, mpd->wbc);
1998                         if (!err && (pages_skipped == mpd->wbc->pages_skipped))
1999                                 /*
2000                                  * have successfully written the page
2001                                  * without skipping the same
2002                                  */
2003                                 mpd->pages_written++;
2004                         /*
2005                          * In error case, we have to continue because
2006                          * remaining pages are still locked
2007                          * XXX: unlock and re-dirty them?
2008                          */
2009                         if (ret == 0)
2010                                 ret = err;
2011                 }
2012                 pagevec_release(&pvec);
2013         }
2014         return ret;
2015 }
2016
2017 /*
2018  * mpage_put_bnr_to_bhs - walk blocks and assign them actual numbers
2019  *
2020  * @mpd->inode - inode to walk through
2021  * @exbh->b_blocknr - first block on a disk
2022  * @exbh->b_size - amount of space in bytes
2023  * @logical - first logical block to start assignment with
2024  *
2025  * the function goes through all passed space and put actual disk
2026  * block numbers into buffer heads, dropping BH_Delay and BH_Unwritten
2027  */
2028 static void mpage_put_bnr_to_bhs(struct mpage_da_data *mpd, sector_t logical,
2029                                  struct buffer_head *exbh)
2030 {
2031         struct inode *inode = mpd->inode;
2032         struct address_space *mapping = inode->i_mapping;
2033         int blocks = exbh->b_size >> inode->i_blkbits;
2034         sector_t pblock = exbh->b_blocknr, cur_logical;
2035         struct buffer_head *head, *bh;
2036         pgoff_t index, end;
2037         struct pagevec pvec;
2038         int nr_pages, i;
2039
2040         index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
2041         end = (logical + blocks - 1) >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
2042         cur_logical = index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
2043
2044         pagevec_init(&pvec, 0);
2045
2046         while (index <= end) {
2047                 /* XXX: optimize tail */
2048                 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
2049                 if (nr_pages == 0)
2050                         break;
2051                 for (i = 0; i < nr_pages; i++) {
2052                         struct page *page = pvec.pages[i];
2053
2054                         index = page->index;
2055                         if (index > end)
2056                                 break;
2057                         index++;
2058
2059                         BUG_ON(!PageLocked(page));
2060                         BUG_ON(PageWriteback(page));
2061                         BUG_ON(!page_has_buffers(page));
2062
2063                         bh = page_buffers(page);
2064                         head = bh;
2065
2066                         /* skip blocks out of the range */
2067                         do {
2068                                 if (cur_logical >= logical)
2069                                         break;
2070                                 cur_logical++;
2071                         } while ((bh = bh->b_this_page) != head);
2072
2073                         do {
2074                                 if (cur_logical >= logical + blocks)
2075                                         break;
2076
2077                                 if (buffer_delay(bh) ||
2078                                                 buffer_unwritten(bh)) {
2079
2080                                         BUG_ON(bh->b_bdev != inode->i_sb->s_bdev);
2081
2082                                         if (buffer_delay(bh)) {
2083                                                 clear_buffer_delay(bh);
2084                                                 bh->b_blocknr = pblock;
2085                                         } else {
2086                                                 /*
2087                                                  * unwritten already should have
2088                                                  * blocknr assigned. Verify that
2089                                                  */
2090                                                 clear_buffer_unwritten(bh);
2091                                                 BUG_ON(bh->b_blocknr != pblock);
2092                                         }
2093
2094                                 } else if (buffer_mapped(bh))
2095                                         BUG_ON(bh->b_blocknr != pblock);
2096
2097                                 cur_logical++;
2098                                 pblock++;
2099                         } while ((bh = bh->b_this_page) != head);
2100                 }
2101                 pagevec_release(&pvec);
2102         }
2103 }
2104
2105
2106 /*
2107  * __unmap_underlying_blocks - just a helper function to unmap
2108  * set of blocks described by @bh
2109  */
2110 static inline void __unmap_underlying_blocks(struct inode *inode,
2111                                              struct buffer_head *bh)
2112 {
2113         struct block_device *bdev = inode->i_sb->s_bdev;
2114         int blocks, i;
2115
2116         blocks = bh->b_size >> inode->i_blkbits;
2117         for (i = 0; i < blocks; i++)
2118                 unmap_underlying_metadata(bdev, bh->b_blocknr + i);
2119 }
2120
2121 static void ext4_da_block_invalidatepages(struct mpage_da_data *mpd,
2122                                         sector_t logical, long blk_cnt)
2123 {
2124         int nr_pages, i;
2125         pgoff_t index, end;
2126         struct pagevec pvec;
2127         struct inode *inode = mpd->inode;
2128         struct address_space *mapping = inode->i_mapping;
2129
2130         index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
2131         end   = (logical + blk_cnt - 1) >>
2132                                 (PAGE_CACHE_SHIFT - inode->i_blkbits);
2133         while (index <= end) {
2134                 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
2135                 if (nr_pages == 0)
2136                         break;
2137                 for (i = 0; i < nr_pages; i++) {
2138                         struct page *page = pvec.pages[i];
2139                         index = page->index;
2140                         if (index > end)
2141                                 break;
2142                         index++;
2143
2144                         BUG_ON(!PageLocked(page));
2145                         BUG_ON(PageWriteback(page));
2146                         block_invalidatepage(page, 0);
2147                         ClearPageUptodate(page);
2148                         unlock_page(page);
2149                 }
2150         }
2151         return;
2152 }
2153
2154 static void ext4_print_free_blocks(struct inode *inode)
2155 {
2156         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
2157         printk(KERN_CRIT "Total free blocks count %lld\n",
2158                ext4_count_free_blocks(inode->i_sb));
2159         printk(KERN_CRIT "Free/Dirty block details\n");
2160         printk(KERN_CRIT "free_blocks=%lld\n",
2161                (long long) percpu_counter_sum(&sbi->s_freeblocks_counter));
2162         printk(KERN_CRIT "dirty_blocks=%lld\n",
2163                (long long) percpu_counter_sum(&sbi->s_dirtyblocks_counter));
2164         printk(KERN_CRIT "Block reservation details\n");
2165         printk(KERN_CRIT "i_reserved_data_blocks=%u\n",
2166                EXT4_I(inode)->i_reserved_data_blocks);
2167         printk(KERN_CRIT "i_reserved_meta_blocks=%u\n",
2168                EXT4_I(inode)->i_reserved_meta_blocks);
2169         return;
2170 }
2171
2172 /*
2173  * mpage_da_map_blocks - go through given space
2174  *
2175  * @mpd - bh describing space
2176  *
2177  * The function skips space we know is already mapped to disk blocks.
2178  *
2179  */
2180 static int mpage_da_map_blocks(struct mpage_da_data *mpd)
2181 {
2182         int err, blks, get_blocks_flags;
2183         struct buffer_head new;
2184         sector_t next = mpd->b_blocknr;
2185         unsigned max_blocks = mpd->b_size >> mpd->inode->i_blkbits;
2186         loff_t disksize = EXT4_I(mpd->inode)->i_disksize;
2187         handle_t *handle = NULL;
2188
2189         /*
2190          * We consider only non-mapped and non-allocated blocks
2191          */
2192         if ((mpd->b_state  & (1 << BH_Mapped)) &&
2193                 !(mpd->b_state & (1 << BH_Delay)) &&
2194                 !(mpd->b_state & (1 << BH_Unwritten)))
2195                 return 0;
2196
2197         /*
2198          * If we didn't accumulate anything to write simply return
2199          */
2200         if (!mpd->b_size)
2201                 return 0;
2202
2203         handle = ext4_journal_current_handle();
2204         BUG_ON(!handle);
2205
2206         /*
2207          * Call ext4_get_blocks() to allocate any delayed allocation
2208          * blocks, or to convert an uninitialized extent to be
2209          * initialized (in the case where we have written into
2210          * one or more preallocated blocks).
2211          *
2212          * We pass in the magic EXT4_GET_BLOCKS_DELALLOC_RESERVE to
2213          * indicate that we are on the delayed allocation path.  This
2214          * affects functions in many different parts of the allocation
2215          * call path.  This flag exists primarily because we don't
2216          * want to change *many* call functions, so ext4_get_blocks()
2217          * will set the magic i_delalloc_reserved_flag once the
2218          * inode's allocation semaphore is taken.
2219          *
2220          * If the blocks in questions were delalloc blocks, set
2221          * EXT4_GET_BLOCKS_DELALLOC_RESERVE so the delalloc accounting
2222          * variables are updated after the blocks have been allocated.
2223          */
2224         new.b_state = 0;
2225         get_blocks_flags = (EXT4_GET_BLOCKS_CREATE |
2226                             EXT4_GET_BLOCKS_DELALLOC_RESERVE);
2227         if (mpd->b_state & (1 << BH_Delay))
2228                 get_blocks_flags |= EXT4_GET_BLOCKS_UPDATE_RESERVE_SPACE;
2229         blks = ext4_get_blocks(handle, mpd->inode, next, max_blocks,
2230                                &new, get_blocks_flags);
2231         if (blks < 0) {
2232                 err = blks;
2233                 /*
2234                  * If get block returns with error we simply
2235                  * return. Later writepage will redirty the page and
2236                  * writepages will find the dirty page again
2237                  */
2238                 if (err == -EAGAIN)
2239                         return 0;
2240
2241                 if (err == -ENOSPC &&
2242                     ext4_count_free_blocks(mpd->inode->i_sb)) {
2243                         mpd->retval = err;
2244                         return 0;
2245                 }
2246
2247                 /*
2248                  * get block failure will cause us to loop in
2249                  * writepages, because a_ops->writepage won't be able
2250                  * to make progress. The page will be redirtied by
2251                  * writepage and writepages will again try to write
2252                  * the same.
2253                  */
2254                 ext4_msg(mpd->inode->i_sb, KERN_CRIT,
2255                          "delayed block allocation failed for inode %lu at "
2256                          "logical offset %llu with max blocks %zd with "
2257                          "error %d\n", mpd->inode->i_ino,
2258                          (unsigned long long) next,
2259                          mpd->b_size >> mpd->inode->i_blkbits, err);
2260                 printk(KERN_CRIT "This should not happen!!  "
2261                        "Data will be lost\n");
2262                 if (err == -ENOSPC) {
2263                         ext4_print_free_blocks(mpd->inode);
2264                 }
2265                 /* invalidate all the pages */
2266                 ext4_da_block_invalidatepages(mpd, next,
2267                                 mpd->b_size >> mpd->inode->i_blkbits);
2268                 return err;
2269         }
2270         BUG_ON(blks == 0);
2271
2272         new.b_size = (blks << mpd->inode->i_blkbits);
2273
2274         if (buffer_new(&new))
2275                 __unmap_underlying_blocks(mpd->inode, &new);
2276
2277         /*
2278          * If blocks are delayed marked, we need to
2279          * put actual blocknr and drop delayed bit
2280          */
2281         if ((mpd->b_state & (1 << BH_Delay)) ||
2282             (mpd->b_state & (1 << BH_Unwritten)))
2283                 mpage_put_bnr_to_bhs(mpd, next, &new);
2284
2285         if (ext4_should_order_data(mpd->inode)) {
2286                 err = ext4_jbd2_file_inode(handle, mpd->inode);
2287                 if (err)
2288                         return err;
2289         }
2290
2291         /*
2292          * Update on-disk size along with block allocation.
2293          */
2294         disksize = ((loff_t) next + blks) << mpd->inode->i_blkbits;
2295         if (disksize > i_size_read(mpd->inode))
2296                 disksize = i_size_read(mpd->inode);
2297         if (disksize > EXT4_I(mpd->inode)->i_disksize) {
2298                 ext4_update_i_disksize(mpd->inode, disksize);
2299                 return ext4_mark_inode_dirty(handle, mpd->inode);
2300         }
2301
2302         return 0;
2303 }
2304
2305 #define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
2306                 (1 << BH_Delay) | (1 << BH_Unwritten))
2307
2308 /*
2309  * mpage_add_bh_to_extent - try to add one more block to extent of blocks
2310  *
2311  * @mpd->lbh - extent of blocks
2312  * @logical - logical number of the block in the file
2313  * @bh - bh of the block (used to access block's state)
2314  *
2315  * the function is used to collect contig. blocks in same state
2316  */
2317 static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
2318                                    sector_t logical, size_t b_size,
2319                                    unsigned long b_state)
2320 {
2321         sector_t next;
2322         int nrblocks = mpd->b_size >> mpd->inode->i_blkbits;
2323
2324         /* check if thereserved journal credits might overflow */
2325         if (!(EXT4_I(mpd->inode)->i_flags & EXT4_EXTENTS_FL)) {
2326                 if (nrblocks >= EXT4_MAX_TRANS_DATA) {
2327                         /*
2328                          * With non-extent format we are limited by the journal
2329                          * credit available.  Total credit needed to insert
2330                          * nrblocks contiguous blocks is dependent on the
2331                          * nrblocks.  So limit nrblocks.
2332                          */
2333                         goto flush_it;
2334                 } else if ((nrblocks + (b_size >> mpd->inode->i_blkbits)) >
2335                                 EXT4_MAX_TRANS_DATA) {
2336                         /*
2337                          * Adding the new buffer_head would make it cross the
2338                          * allowed limit for which we have journal credit
2339                          * reserved. So limit the new bh->b_size
2340                          */
2341                         b_size = (EXT4_MAX_TRANS_DATA - nrblocks) <<
2342                                                 mpd->inode->i_blkbits;
2343                         /* we will do mpage_da_submit_io in the next loop */
2344                 }
2345         }
2346         /*
2347          * First block in the extent
2348          */
2349         if (mpd->b_size == 0) {
2350                 mpd->b_blocknr = logical;
2351                 mpd->b_size = b_size;
2352                 mpd->b_state = b_state & BH_FLAGS;
2353                 return;
2354         }
2355
2356         next = mpd->b_blocknr + nrblocks;
2357         /*
2358          * Can we merge the block to our big extent?
2359          */
2360         if (logical == next && (b_state & BH_FLAGS) == mpd->b_state) {
2361                 mpd->b_size += b_size;
2362                 return;
2363         }
2364
2365 flush_it:
2366         /*
2367          * We couldn't merge the block to our extent, so we
2368          * need to flush current  extent and start new one
2369          */
2370         if (mpage_da_map_blocks(mpd) == 0)
2371                 mpage_da_submit_io(mpd);
2372         mpd->io_done = 1;
2373         return;
2374 }
2375
2376 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh)
2377 {
2378         return (buffer_delay(bh) || buffer_unwritten(bh)) && buffer_dirty(bh);
2379 }
2380
2381 /*
2382  * __mpage_da_writepage - finds extent of pages and blocks
2383  *
2384  * @page: page to consider
2385  * @wbc: not used, we just follow rules
2386  * @data: context
2387  *
2388  * The function finds extents of pages and scan them for all blocks.
2389  */
2390 static int __mpage_da_writepage(struct page *page,
2391                                 struct writeback_control *wbc, void *data)
2392 {
2393         struct mpage_da_data *mpd = data;
2394         struct inode *inode = mpd->inode;
2395         struct buffer_head *bh, *head;
2396         sector_t logical;
2397
2398         if (mpd->io_done) {
2399                 /*
2400                  * Rest of the page in the page_vec
2401                  * redirty then and skip then. We will
2402                  * try to write them again after
2403                  * starting a new transaction
2404                  */
2405                 redirty_page_for_writepage(wbc, page);
2406                 unlock_page(page);
2407                 return MPAGE_DA_EXTENT_TAIL;
2408         }
2409         /*
2410          * Can we merge this page to current extent?
2411          */
2412         if (mpd->next_page != page->index) {
2413                 /*
2414                  * Nope, we can't. So, we map non-allocated blocks
2415                  * and start IO on them using writepage()
2416                  */
2417                 if (mpd->next_page != mpd->first_page) {
2418                         if (mpage_da_map_blocks(mpd) == 0)
2419                                 mpage_da_submit_io(mpd);
2420                         /*
2421                          * skip rest of the page in the page_vec
2422                          */
2423                         mpd->io_done = 1;
2424                         redirty_page_for_writepage(wbc, page);
2425                         unlock_page(page);
2426                         return MPAGE_DA_EXTENT_TAIL;
2427                 }
2428
2429                 /*
2430                  * Start next extent of pages ...
2431                  */
2432                 mpd->first_page = page->index;
2433
2434                 /*
2435                  * ... and blocks
2436                  */
2437                 mpd->b_size = 0;
2438                 mpd->b_state = 0;
2439                 mpd->b_blocknr = 0;
2440         }
2441
2442         mpd->next_page = page->index + 1;
2443         logical = (sector_t) page->index <<
2444                   (PAGE_CACHE_SHIFT - inode->i_blkbits);
2445
2446         if (!page_has_buffers(page)) {
2447                 mpage_add_bh_to_extent(mpd, logical, PAGE_CACHE_SIZE,
2448                                        (1 << BH_Dirty) | (1 << BH_Uptodate));
2449                 if (mpd->io_done)
2450                         return MPAGE_DA_EXTENT_TAIL;
2451         } else {
2452                 /*
2453                  * Page with regular buffer heads, just add all dirty ones
2454                  */
2455                 head = page_buffers(page);
2456                 bh = head;
2457                 do {
2458                         BUG_ON(buffer_locked(bh));
2459                         /*
2460                          * We need to try to allocate
2461                          * unmapped blocks in the same page.
2462                          * Otherwise we won't make progress
2463                          * with the page in ext4_writepage
2464                          */
2465                         if (ext4_bh_delay_or_unwritten(NULL, bh)) {
2466                                 mpage_add_bh_to_extent(mpd, logical,
2467                                                        bh->b_size,
2468                                                        bh->b_state);
2469                                 if (mpd->io_done)
2470                                         return MPAGE_DA_EXTENT_TAIL;
2471                         } else if (buffer_dirty(bh) && (buffer_mapped(bh))) {
2472                                 /*
2473                                  * mapped dirty buffer. We need to update
2474                                  * the b_state because we look at
2475                                  * b_state in mpage_da_map_blocks. We don't
2476                                  * update b_size because if we find an
2477                                  * unmapped buffer_head later we need to
2478                                  * use the b_state flag of that buffer_head.
2479                                  */
2480                                 if (mpd->b_size == 0)
2481                                         mpd->b_state = bh->b_state & BH_FLAGS;
2482                         }
2483                         logical++;
2484                 } while ((bh = bh->b_this_page) != head);
2485         }
2486
2487         return 0;
2488 }
2489
2490 /*
2491  * This is a special get_blocks_t callback which is used by
2492  * ext4_da_write_begin().  It will either return mapped block or
2493  * reserve space for a single block.
2494  *
2495  * For delayed buffer_head we have BH_Mapped, BH_New, BH_Delay set.
2496  * We also have b_blocknr = -1 and b_bdev initialized properly
2497  *
2498  * For unwritten buffer_head we have BH_Mapped, BH_New, BH_Unwritten set.
2499  * We also have b_blocknr = physicalblock mapping unwritten extent and b_bdev
2500  * initialized properly.
2501  */
2502 static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
2503                                   struct buffer_head *bh_result, int create)
2504 {
2505         int ret = 0;
2506         sector_t invalid_block = ~((sector_t) 0xffff);
2507
2508         if (invalid_block < ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es))
2509                 invalid_block = ~0;
2510
2511         BUG_ON(create == 0);
2512         BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
2513
2514         /*
2515          * first, we need to know whether the block is allocated already
2516          * preallocated blocks are unmapped but should treated
2517          * the same as allocated blocks.
2518          */
2519         ret = ext4_get_blocks(NULL, inode, iblock, 1,  bh_result, 0);
2520         if ((ret == 0) && !buffer_delay(bh_result)) {
2521                 /* the block isn't (pre)allocated yet, let's reserve space */
2522                 /*
2523                  * XXX: __block_prepare_write() unmaps passed block,
2524                  * is it OK?
2525                  */
2526                 ret = ext4_da_reserve_space(inode, 1);
2527                 if (ret)
2528                         /* not enough space to reserve */
2529                         return ret;
2530
2531                 map_bh(bh_result, inode->i_sb, invalid_block);
2532                 set_buffer_new(bh_result);
2533                 set_buffer_delay(bh_result);
2534         } else if (ret > 0) {
2535                 bh_result->b_size = (ret << inode->i_blkbits);
2536                 if (buffer_unwritten(bh_result)) {
2537                         /* A delayed write to unwritten bh should
2538                          * be marked new and mapped.  Mapped ensures
2539                          * that we don't do get_block multiple times
2540                          * when we write to the same offset and new
2541                          * ensures that we do proper zero out for
2542                          * partial write.
2543                          */
2544                         set_buffer_new(bh_result);
2545                         set_buffer_mapped(bh_result);
2546                 }
2547                 ret = 0;
2548         }
2549
2550         return ret;
2551 }
2552
2553 /*
2554  * This function is used as a standard get_block_t calback function
2555  * when there is no desire to allocate any blocks.  It is used as a
2556  * callback function for block_prepare_write(), nobh_writepage(), and
2557  * block_write_full_page().  These functions should only try to map a
2558  * single block at a time.
2559  *
2560  * Since this function doesn't do block allocations even if the caller
2561  * requests it by passing in create=1, it is critically important that
2562  * any caller checks to make sure that any buffer heads are returned
2563  * by this function are either all already mapped or marked for
2564  * delayed allocation before calling nobh_writepage() or
2565  * block_write_full_page().  Otherwise, b_blocknr could be left
2566  * unitialized, and the page write functions will be taken by
2567  * surprise.
2568  */
2569 static int noalloc_get_block_write(struct inode *inode, sector_t iblock,
2570                                    struct buffer_head *bh_result, int create)
2571 {
2572         int ret = 0;
2573         unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
2574
2575         BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
2576
2577         /*
2578          * we don't want to do block allocation in writepage
2579          * so call get_block_wrap with create = 0
2580          */
2581         ret = ext4_get_blocks(NULL, inode, iblock, max_blocks, bh_result, 0);
2582         if (ret > 0) {
2583                 bh_result->b_size = (ret << inode->i_blkbits);
2584                 ret = 0;
2585         }
2586         return ret;
2587 }
2588
2589 static int bget_one(handle_t *handle, struct buffer_head *bh)
2590 {
2591         get_bh(bh);
2592         return 0;
2593 }
2594
2595 static int bput_one(handle_t *handle, struct buffer_head *bh)
2596 {
2597         put_bh(bh);
2598         return 0;
2599 }
2600
2601 static int __ext4_journalled_writepage(struct page *page,
2602                                        struct writeback_control *wbc,
2603                                        unsigned int len)
2604 {
2605         struct address_space *mapping = page->mapping;
2606         struct inode *inode = mapping->host;
2607         struct buffer_head *page_bufs;
2608         handle_t *handle = NULL;
2609         int ret = 0;
2610         int err;
2611
2612         page_bufs = page_buffers(page);
2613         BUG_ON(!page_bufs);
2614         walk_page_buffers(handle, page_bufs, 0, len, NULL, bget_one);
2615         /* As soon as we unlock the page, it can go away, but we have
2616          * references to buffers so we are safe */
2617         unlock_page(page);
2618
2619         handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
2620         if (IS_ERR(handle)) {
2621                 ret = PTR_ERR(handle);
2622                 goto out;
2623         }
2624
2625         ret = walk_page_buffers(handle, page_bufs, 0, len, NULL,
2626                                 do_journal_get_write_access);
2627
2628         err = walk_page_buffers(handle, page_bufs, 0, len, NULL,
2629                                 write_end_fn);
2630         if (ret == 0)
2631                 ret = err;
2632         err = ext4_journal_stop(handle);
2633         if (!ret)
2634                 ret = err;
2635
2636         walk_page_buffers(handle, page_bufs, 0, len, NULL, bput_one);
2637         EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
2638 out:
2639         return ret;
2640 }
2641
2642 /*
2643  * Note that we don't need to start a transaction unless we're journaling data
2644  * because we should have holes filled from ext4_page_mkwrite(). We even don't
2645  * need to file the inode to the transaction's list in ordered mode because if
2646  * we are writing back data added by write(), the inode is already there and if
2647  * we are writing back data modified via mmap(), noone guarantees in which
2648  * transaction the data will hit the disk. In case we are journaling data, we
2649  * cannot start transaction directly because transaction start ranks above page
2650  * lock so we have to do some magic.
2651  *
2652  * This function can get called via...
2653  *   - ext4_da_writepages after taking page lock (have journal handle)
2654  *   - journal_submit_inode_data_buffers (no journal handle)
2655  *   - shrink_page_list via pdflush (no journal handle)
2656  *   - grab_page_cache when doing write_begin (have journal handle)
2657  *
2658  * We don't do any block allocation in this function. If we have page with
2659  * multiple blocks we need to write those buffer_heads that are mapped. This
2660  * is important for mmaped based write. So if we do with blocksize 1K
2661  * truncate(f, 1024);
2662  * a = mmap(f, 0, 4096);
2663  * a[0] = 'a';
2664  * truncate(f, 4096);
2665  * we have in the page first buffer_head mapped via page_mkwrite call back
2666  * but other bufer_heads would be unmapped but dirty(dirty done via the
2667  * do_wp_page). So writepage should write the first block. If we modify
2668  * the mmap area beyond 1024 we will again get a page_fault and the
2669  * page_mkwrite callback will do the block allocation and mark the
2670  * buffer_heads mapped.
2671  *
2672  * We redirty the page if we have any buffer_heads that is either delay or
2673  * unwritten in the page.
2674  *
2675  * We can get recursively called as show below.
2676  *
2677  *      ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
2678  *              ext4_writepage()
2679  *
2680  * But since we don't do any block allocation we should not deadlock.
2681  * Page also have the dirty flag cleared so we don't get recurive page_lock.
2682  */
2683 static int ext4_writepage(struct page *page,
2684                           struct writeback_control *wbc)
2685 {
2686         int ret = 0;
2687         loff_t size;
2688         unsigned int len;
2689         struct buffer_head *page_bufs;
2690         struct inode *inode = page->mapping->host;
2691
2692         trace_ext4_writepage(inode, page);
2693         size = i_size_read(inode);
2694         if (page->index == size >> PAGE_CACHE_SHIFT)
2695                 len = size & ~PAGE_CACHE_MASK;
2696         else
2697                 len = PAGE_CACHE_SIZE;
2698
2699         if (page_has_buffers(page)) {
2700                 page_bufs = page_buffers(page);
2701                 if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
2702                                         ext4_bh_delay_or_unwritten)) {
2703                         /*
2704                          * We don't want to do  block allocation
2705                          * So redirty the page and return
2706                          * We may reach here when we do a journal commit
2707                          * via journal_submit_inode_data_buffers.
2708                          * If we don't have mapping block we just ignore
2709                          * them. We can also reach here via shrink_page_list
2710                          */
2711                         redirty_page_for_writepage(wbc, page);
2712                         unlock_page(page);
2713                         return 0;
2714                 }
2715         } else {
2716                 /*
2717                  * The test for page_has_buffers() is subtle:
2718                  * We know the page is dirty but it lost buffers. That means
2719                  * that at some moment in time after write_begin()/write_end()
2720                  * has been called all buffers have been clean and thus they
2721                  * must have been written at least once. So they are all
2722                  * mapped and we can happily proceed with mapping them
2723                  * and writing the page.
2724                  *
2725                  * Try to initialize the buffer_heads and check whether
2726                  * all are mapped and non delay. We don't want to
2727                  * do block allocation here.
2728                  */
2729                 ret = block_prepare_write(page, 0, len,
2730                                           noalloc_get_block_write);
2731                 if (!ret) {
2732                         page_bufs = page_buffers(page);
2733                         /* check whether all are mapped and non delay */
2734                         if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
2735                                                 ext4_bh_delay_or_unwritten)) {
2736                                 redirty_page_for_writepage(wbc, page);
2737                                 unlock_page(page);
2738                                 return 0;
2739                         }
2740                 } else {
2741                         /*
2742                          * We can't do block allocation here
2743                          * so just redity the page and unlock
2744                          * and return
2745                          */
2746                         redirty_page_for_writepage(wbc, page);
2747                         unlock_page(page);
2748                         return 0;
2749                 }
2750                 /* now mark the buffer_heads as dirty and uptodate */
2751                 block_commit_write(page, 0, len);
2752         }
2753
2754         if (PageChecked(page) && ext4_should_journal_data(inode)) {
2755                 /*
2756                  * It's mmapped pagecache.  Add buffers and journal it.  There
2757                  * doesn't seem much point in redirtying the page here.
2758                  */
2759                 ClearPageChecked(page);
2760                 return __ext4_journalled_writepage(page, wbc, len);
2761         }
2762
2763         if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
2764                 ret = nobh_writepage(page, noalloc_get_block_write, wbc);
2765         else
2766                 ret = block_write_full_page(page, noalloc_get_block_write,
2767                                             wbc);
2768
2769         return ret;
2770 }
2771
2772 /*
2773  * This is called via ext4_da_writepages() to
2774  * calulate the total number of credits to reserve to fit
2775  * a single extent allocation into a single transaction,
2776  * ext4_da_writpeages() will loop calling this before
2777  * the block allocation.
2778  */
2779
2780 static int ext4_da_writepages_trans_blocks(struct inode *inode)
2781 {
2782         int max_blocks = EXT4_I(inode)->i_reserved_data_blocks;
2783
2784         /*
2785          * With non-extent format the journal credit needed to
2786          * insert nrblocks contiguous block is dependent on
2787          * number of contiguous block. So we will limit
2788          * number of contiguous block to a sane value
2789          */
2790         if (!(inode->i_flags & EXT4_EXTENTS_FL) &&
2791             (max_blocks > EXT4_MAX_TRANS_DATA))
2792                 max_blocks = EXT4_MAX_TRANS_DATA;
2793
2794         return ext4_chunk_trans_blocks(inode, max_blocks);
2795 }
2796
2797 static int ext4_da_writepages(struct address_space *mapping,
2798                               struct writeback_control *wbc)
2799 {
2800         pgoff_t index;
2801         int range_whole = 0;
2802         handle_t *handle = NULL;
2803         struct mpage_da_data mpd;
2804         struct inode *inode = mapping->host;
2805         int no_nrwrite_index_update;
2806         int pages_written = 0;
2807         long pages_skipped;
2808         unsigned int max_pages;
2809         int range_cyclic, cycled = 1, io_done = 0;
2810         int needed_blocks, ret = 0;
2811         long desired_nr_to_write, nr_to_writebump = 0;
2812         loff_t range_start = wbc->range_start;
2813         struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
2814
2815         trace_ext4_da_writepages(inode, wbc);
2816
2817         /*
2818          * No pages to write? This is mainly a kludge to avoid starting
2819          * a transaction for special inodes like journal inode on last iput()
2820          * because that could violate lock ordering on umount
2821          */
2822         if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2823                 return 0;
2824
2825         /*
2826          * If the filesystem has aborted, it is read-only, so return
2827          * right away instead of dumping stack traces later on that
2828          * will obscure the real source of the problem.  We test
2829          * EXT4_MF_FS_ABORTED instead of sb->s_flag's MS_RDONLY because
2830          * the latter could be true if the filesystem is mounted
2831          * read-only, and in that case, ext4_da_writepages should
2832          * *never* be called, so if that ever happens, we would want
2833          * the stack trace.
2834          */
2835         if (unlikely(sbi->s_mount_flags & EXT4_MF_FS_ABORTED))
2836                 return -EROFS;
2837
2838         if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
2839                 range_whole = 1;
2840
2841         range_cyclic = wbc->range_cyclic;
2842         if (wbc->range_cyclic) {
2843                 index = mapping->writeback_index;
2844                 if (index)
2845                         cycled = 0;
2846                 wbc->range_start = index << PAGE_CACHE_SHIFT;
2847                 wbc->range_end  = LLONG_MAX;
2848                 wbc->range_cyclic = 0;
2849         } else
2850                 index = wbc->range_start >> PAGE_CACHE_SHIFT;
2851
2852         /*
2853          * This works around two forms of stupidity.  The first is in
2854          * the writeback code, which caps the maximum number of pages
2855          * written to be 1024 pages.  This is wrong on multiple
2856          * levels; different architectues have a different page size,
2857          * which changes the maximum amount of data which gets
2858          * written.  Secondly, 4 megabytes is way too small.  XFS
2859          * forces this value to be 16 megabytes by multiplying
2860          * nr_to_write parameter by four, and then relies on its
2861          * allocator to allocate larger extents to make them
2862          * contiguous.  Unfortunately this brings us to the second
2863          * stupidity, which is that ext4's mballoc code only allocates
2864          * at most 2048 blocks.  So we force contiguous writes up to
2865          * the number of dirty blocks in the inode, or
2866          * sbi->max_writeback_mb_bump whichever is smaller.
2867          */
2868         max_pages = sbi->s_max_writeback_mb_bump << (20 - PAGE_CACHE_SHIFT);
2869         if (!range_cyclic && range_whole)
2870                 desired_nr_to_write = wbc->nr_to_write * 8;
2871         else
2872                 desired_nr_to_write = ext4_num_dirty_pages(inode, index,
2873                                                            max_pages);
2874         if (desired_nr_to_write > max_pages)
2875                 desired_nr_to_write = max_pages;
2876
2877         if (wbc->nr_to_write < desired_nr_to_write) {
2878                 nr_to_writebump = desired_nr_to_write - wbc->nr_to_write;
2879                 wbc->nr_to_write = desired_nr_to_write;
2880         }
2881
2882         mpd.wbc = wbc;
2883         mpd.inode = mapping->host;
2884
2885         /*
2886          * we don't want write_cache_pages to update
2887          * nr_to_write and writeback_index
2888          */
2889         no_nrwrite_index_update = wbc->no_nrwrite_index_update;
2890         wbc->no_nrwrite_index_update = 1;
2891         pages_skipped = wbc->pages_skipped;
2892
2893 retry:
2894         while (!ret && wbc->nr_to_write > 0) {
2895
2896                 /*
2897                  * we  insert one extent at a time. So we need
2898                  * credit needed for single extent allocation.
2899                  * journalled mode is currently not supported
2900                  * by delalloc
2901                  */
2902                 BUG_ON(ext4_should_journal_data(inode));
2903                 needed_blocks = ext4_da_writepages_trans_blocks(inode);
2904
2905                 /* start a new transaction*/
2906                 handle = ext4_journal_start(inode, needed_blocks);
2907                 if (IS_ERR(handle)) {
2908                         ret = PTR_ERR(handle);
2909                         ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: "
2910                                "%ld pages, ino %lu; err %d\n", __func__,
2911                                 wbc->nr_to_write, inode->i_ino, ret);
2912                         goto out_writepages;
2913                 }
2914
2915                 /*
2916                  * Now call __mpage_da_writepage to find the next
2917                  * contiguous region of logical blocks that need
2918                  * blocks to be allocated by ext4.  We don't actually
2919                  * submit the blocks for I/O here, even though
2920                  * write_cache_pages thinks it will, and will set the
2921                  * pages as clean for write before calling
2922                  * __mpage_da_writepage().
2923                  */
2924                 mpd.b_size = 0;
2925                 mpd.b_state = 0;
2926                 mpd.b_blocknr = 0;
2927                 mpd.first_page = 0;
2928                 mpd.next_page = 0;
2929                 mpd.io_done = 0;
2930                 mpd.pages_written = 0;
2931                 mpd.retval = 0;
2932                 ret = write_cache_pages(mapping, wbc, __mpage_da_writepage,
2933                                         &mpd);
2934                 /*
2935                  * If we have a contigous extent of pages and we
2936                  * haven't done the I/O yet, map the blocks and submit
2937                  * them for I/O.
2938                  */
2939                 if (!mpd.io_done && mpd.next_page != mpd.first_page) {
2940                         if (mpage_da_map_blocks(&mpd) == 0)
2941                                 mpage_da_submit_io(&mpd);
2942                         mpd.io_done = 1;
2943                         ret = MPAGE_DA_EXTENT_TAIL;
2944                 }
2945                 trace_ext4_da_write_pages(inode, &mpd);
2946                 wbc->nr_to_write -= mpd.pages_written;
2947
2948                 ext4_journal_stop(handle);
2949
2950                 if ((mpd.retval == -ENOSPC) && sbi->s_journal) {
2951                         /* commit the transaction which would
2952                          * free blocks released in the transaction
2953                          * and try again
2954                          */
2955                         jbd2_journal_force_commit_nested(sbi->s_journal);
2956                         wbc->pages_skipped = pages_skipped;
2957                         ret = 0;
2958                 } else if (ret == MPAGE_DA_EXTENT_TAIL) {
2959                         /*
2960                          * got one extent now try with
2961                          * rest of the pages
2962                          */
2963                         pages_written += mpd.pages_written;
2964                         wbc->pages_skipped = pages_skipped;
2965                         ret = 0;
2966                         io_done = 1;
2967                 } else if (wbc->nr_to_write)
2968                         /*
2969                          * There is no more writeout needed
2970                          * or we requested for a noblocking writeout
2971                          * and we found the device congested
2972                          */
2973                         break;
2974         }
2975         if (!io_done && !cycled) {
2976                 cycled = 1;
2977                 index = 0;
2978                 wbc->range_start = index << PAGE_CACHE_SHIFT;
2979                 wbc->range_end  = mapping->writeback_index - 1;
2980                 goto retry;
2981         }
2982         if (pages_skipped != wbc->pages_skipped)
2983                 ext4_msg(inode->i_sb, KERN_CRIT,
2984                          "This should not happen leaving %s "
2985                          "with nr_to_write = %ld ret = %d\n",
2986                          __func__, wbc->nr_to_write, ret);
2987
2988         /* Update index */
2989         index += pages_written;
2990         wbc->range_cyclic = range_cyclic;
2991         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
2992                 /*
2993                  * set the writeback_index so that range_cyclic
2994                  * mode will write it back later
2995                  */
2996                 mapping->writeback_index = index;
2997
2998 out_writepages:
2999         if (!no_nrwrite_index_update)
3000                 wbc->no_nrwrite_index_update = 0;
3001         if (wbc->nr_to_write > nr_to_writebump)
3002                 wbc->nr_to_write -= nr_to_writebump;
3003         wbc->range_start = range_start;
3004         trace_ext4_da_writepages_result(inode, wbc, ret, pages_written);
3005         return ret;
3006 }
3007
3008 #define FALL_BACK_TO_NONDELALLOC 1
3009 static int ext4_nonda_switch(struct super_block *sb)
3010 {
3011         s64 free_blocks, dirty_blocks;
3012         struct ext4_sb_info *sbi = EXT4_SB(sb);
3013
3014         /*
3015          * switch to non delalloc mode if we are running low
3016          * on free block. The free block accounting via percpu
3017          * counters can get slightly wrong with percpu_counter_batch getting
3018          * accumulated on each CPU without updating global counters
3019          * Delalloc need an accurate free block accounting. So switch
3020          * to non delalloc when we are near to error range.
3021          */
3022         free_blocks  = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
3023         dirty_blocks = percpu_counter_read_positive(&sbi->s_dirtyblocks_counter);
3024         if (2 * free_blocks < 3 * dirty_blocks ||
3025                 free_blocks < (dirty_blocks + EXT4_FREEBLOCKS_WATERMARK)) {
3026                 /*
3027                  * free block count is less that 150% of dirty blocks
3028                  * or free blocks is less that watermark
3029                  */
3030                 return 1;
3031         }
3032         return 0;
3033 }
3034
3035 static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
3036                                loff_t pos, unsigned len, unsigned flags,
3037                                struct page **pagep, void **fsdata)
3038 {
3039         int ret, retries = 0;
3040         struct page *page;
3041         pgoff_t index;
3042         unsigned from, to;
3043         struct inode *inode = mapping->host;
3044         handle_t *handle;
3045
3046         index = pos >> PAGE_CACHE_SHIFT;
3047         from = pos & (PAGE_CACHE_SIZE - 1);
3048         to = from + len;
3049
3050         if (ext4_nonda_switch(inode->i_sb)) {
3051                 *fsdata = (void *)FALL_BACK_TO_NONDELALLOC;
3052                 return ext4_write_begin(file, mapping, pos,
3053                                         len, flags, pagep, fsdata);
3054         }
3055         *fsdata = (void *)0;
3056         trace_ext4_da_write_begin(inode, pos, len, flags);
3057 retry:
3058         /*
3059          * With delayed allocation, we don't log the i_disksize update
3060          * if there is delayed block allocation. But we still need
3061          * to journalling the i_disksize update if writes to the end
3062          * of file which has an already mapped buffer.
3063          */
3064         handle = ext4_journal_start(inode, 1);
3065         if (IS_ERR(handle)) {
3066                 ret = PTR_ERR(handle);
3067                 goto out;
3068         }
3069         /* We cannot recurse into the filesystem as the transaction is already
3070          * started */
3071         flags |= AOP_FLAG_NOFS;
3072
3073         page = grab_cache_page_write_begin(mapping, index, flags);
3074         if (!page) {
3075                 ext4_journal_stop(handle);
3076                 ret = -ENOMEM;
3077                 goto out;
3078         }
3079         *pagep = page;
3080
3081         ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
3082                                 ext4_da_get_block_prep);
3083         if (ret < 0) {
3084                 unlock_page(page);
3085                 ext4_journal_stop(handle);
3086                 page_cache_release(page);
3087                 /*
3088                  * block_write_begin may have instantiated a few blocks
3089                  * outside i_size.  Trim these off again. Don't need
3090                  * i_size_read because we hold i_mutex.
3091                  */
3092                 if (pos + len > inode->i_size)
3093                         ext4_truncate(inode);
3094         }
3095
3096         if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
3097                 goto retry;
3098 out:
3099         return ret;
3100 }
3101
3102 /*
3103  * Check if we should update i_disksize
3104  * when write to the end of file but not require block allocation
3105  */
3106 static int ext4_da_should_update_i_disksize(struct page *page,
3107                                             unsigned long offset)
3108 {
3109         struct buffer_head *bh;
3110         struct inode *inode = page->mapping->host;
3111         unsigned int idx;
3112         int i;
3113
3114         bh = page_buffers(page);
3115         idx = offset >> inode->i_blkbits;
3116
3117         for (i = 0; i < idx; i++)
3118                 bh = bh->b_this_page;
3119
3120         if (!buffer_mapped(bh) || (buffer_delay(bh)) || buffer_unwritten(bh))
3121                 return 0;
3122         return 1;
3123 }
3124
3125 static int ext4_da_write_end(struct file *file,
3126                              struct address_space *mapping,
3127                              loff_t pos, unsigned len, unsigned copied,
3128                              struct page *page, void *fsdata)
3129 {
3130         struct inode *inode = mapping->host;
3131         int ret = 0, ret2;
3132         handle_t *handle = ext4_journal_current_handle();
3133         loff_t new_i_size;
3134         unsigned long start, end;
3135         int write_mode = (int)(unsigned long)fsdata;
3136
3137         if (write_mode == FALL_BACK_TO_NONDELALLOC) {
3138                 if (ext4_should_order_data(inode)) {
3139                         return ext4_ordered_write_end(file, mapping, pos,
3140                                         len, copied, page, fsdata);
3141                 } else if (ext4_should_writeback_data(inode)) {
3142                         return ext4_writeback_write_end(file, mapping, pos,
3143                                         len, copied, page, fsdata);
3144                 } else {
3145                         BUG();
3146                 }
3147         }
3148
3149         trace_ext4_da_write_end(inode, pos, len, copied);
3150         start = pos & (PAGE_CACHE_SIZE - 1);
3151         end = start + copied - 1;
3152
3153         /*
3154          * generic_write_end() will run mark_inode_dirty() if i_size
3155          * changes.  So let's piggyback the i_disksize mark_inode_dirty
3156          * into that.
3157          */
3158
3159         new_i_size = pos + copied;
3160         if (new_i_size > EXT4_I(inode)->i_disksize) {
3161                 if (ext4_da_should_update_i_disksize(page, end)) {
3162                         down_write(&EXT4_I(inode)->i_data_sem);
3163                         if (new_i_size > EXT4_I(inode)->i_disksize) {
3164                                 /*
3165                                  * Updating i_disksize when extending file
3166                                  * without needing block allocation
3167                                  */
3168                                 if (ext4_should_order_data(inode))
3169                                         ret = ext4_jbd2_file_inode(handle,
3170                                                                    inode);
3171
3172                                 EXT4_I(inode)->i_disksize = new_i_size;
3173                         }
3174                         up_write(&EXT4_I(inode)->i_data_sem);
3175                         /* We need to mark inode dirty even if
3176                          * new_i_size is less that inode->i_size
3177                          * bu greater than i_disksize.(hint delalloc)
3178                          */
3179                         ext4_mark_inode_dirty(handle, inode);
3180                 }
3181         }
3182         ret2 = generic_write_end(file, mapping, pos, len, copied,
3183                                                         page, fsdata);
3184         copied = ret2;
3185         if (ret2 < 0)
3186                 ret = ret2;
3187         ret2 = ext4_journal_stop(handle);
3188         if (!ret)
3189                 ret = ret2;
3190
3191         return ret ? ret : copied;
3192 }
3193
3194 static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
3195 {
3196         /*
3197          * Drop reserved blocks
3198          */
3199         BUG_ON(!PageLocked(page));
3200         if (!page_has_buffers(page))
3201                 goto out;
3202
3203         ext4_da_page_release_reservation(page, offset);
3204
3205 out:
3206         ext4_invalidatepage(page, offset);
3207
3208         return;
3209 }
3210
3211 /*
3212  * Force all delayed allocation blocks to be allocated for a given inode.
3213  */
3214 int ext4_alloc_da_blocks(struct inode *inode)
3215 {
3216         trace_ext4_alloc_da_blocks(inode);
3217
3218         if (!EXT4_I(inode)->i_reserved_data_blocks &&
3219             !EXT4_I(inode)->i_reserved_meta_blocks)
3220                 return 0;
3221
3222         /*
3223          * We do something simple for now.  The filemap_flush() will
3224          * also start triggering a write of the data blocks, which is
3225          * not strictly speaking necessary (and for users of
3226          * laptop_mode, not even desirable).  However, to do otherwise
3227          * would require replicating code paths in:
3228          *
3229          * ext4_da_writepages() ->
3230          *    write_cache_pages() ---> (via passed in callback function)
3231          *        __mpage_da_writepage() -->
3232          *           mpage_add_bh_to_extent()
3233          *           mpage_da_map_blocks()
3234          *
3235          * The problem is that write_cache_pages(), located in
3236          * mm/page-writeback.c, marks pages clean in preparation for
3237          * doing I/O, which is not desirable if we're not planning on
3238          * doing I/O at all.
3239          *
3240          * We could call write_cache_pages(), and then redirty all of
3241          * the pages by calling redirty_page_for_writeback() but that
3242          * would be ugly in the extreme.  So instead we would need to
3243          * replicate parts of the code in the above functions,
3244          * simplifying them becuase we wouldn't actually intend to
3245          * write out the pages, but rather only collect contiguous
3246          * logical block extents, call the multi-block allocator, and
3247          * then update the buffer heads with the block allocations.
3248          *
3249          * For now, though, we'll cheat by calling filemap_flush(),
3250          * which will map the blocks, and start the I/O, but not
3251          * actually wait for the I/O to complete.
3252          */
3253         return filemap_flush(inode->i_mapping);
3254 }
3255
3256 /*
3257  * bmap() is special.  It gets used by applications such as lilo and by
3258  * the swapper to find the on-disk block of a specific piece of data.
3259  *
3260  * Naturally, this is dangerous if the block concerned is still in the
3261  * journal.  If somebody makes a swapfile on an ext4 data-journaling
3262  * filesystem and enables swap, then they may get a nasty shock when the
3263  * data getting swapped to that swapfile suddenly gets overwritten by
3264  * the original zero's written out previously to the journal and
3265  * awaiting writeback in the kernel's buffer cache.
3266  *
3267  * So, if we see any bmap calls here on a modified, data-journaled file,
3268  * take extra steps to flush any blocks which might be in the cache.
3269  */
3270 static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
3271 {
3272         struct inode *inode = mapping->host;
3273         journal_t *journal;
3274         int err;
3275
3276         if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
3277                         test_opt(inode->i_sb, DELALLOC)) {
3278                 /*
3279                  * With delalloc we want to sync the file
3280                  * so that we can make sure we allocate
3281                  * blocks for file
3282                  */
3283                 filemap_write_and_wait(mapping);
3284         }
3285
3286         if (EXT4_JOURNAL(inode) && EXT4_I(inode)->i_state & EXT4_STATE_JDATA) {
3287                 /*
3288                  * This is a REALLY heavyweight approach, but the use of
3289                  * bmap on dirty files is expected to be extremely rare:
3290                  * only if we run lilo or swapon on a freshly made file
3291                  * do we expect this to happen.
3292                  *
3293                  * (bmap requires CAP_SYS_RAWIO so this does not
3294                  * represent an unprivileged user DOS attack --- we'd be
3295                  * in trouble if mortal users could trigger this path at
3296                  * will.)
3297                  *
3298                  * NB. EXT4_STATE_JDATA is not set on files other than
3299                  * regular files.  If somebody wants to bmap a directory
3300                  * or symlink and gets confused because the buffer
3301                  * hasn't yet been flushed to disk, they deserve
3302                  * everything they get.
3303                  */
3304
3305                 EXT4_I(inode)->i_state &= ~EXT4_STATE_JDATA;
3306                 journal = EXT4_JOURNAL(inode);
3307                 jbd2_journal_lock_updates(journal);
3308                 err = jbd2_journal_flush(journal);
3309                 jbd2_journal_unlock_updates(journal);
3310
3311                 if (err)
3312                         return 0;
3313         }
3314
3315         return generic_block_bmap(mapping, block, ext4_get_block);
3316 }
3317
3318 static int ext4_readpage(struct file *file, struct page *page)
3319 {
3320         return mpage_readpage(page, ext4_get_block);
3321 }
3322
3323 static int
3324 ext4_readpages(struct file *file, struct address_space *mapping,
3325                 struct list_head *pages, unsigned nr_pages)
3326 {
3327         return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
3328 }
3329
3330 static void ext4_invalidatepage(struct page *page, unsigned long offset)
3331 {
3332         journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3333
3334         /*
3335          * If it's a full truncate we just forget about the pending dirtying
3336          */
3337         if (offset == 0)
3338                 ClearPageChecked(page);
3339
3340         if (journal)
3341                 jbd2_journal_invalidatepage(journal, page, offset);
3342         else
3343                 block_invalidatepage(page, offset);
3344 }
3345
3346 static int ext4_releasepage(struct page *page, gfp_t wait)
3347 {
3348         journal_t *journal = EXT4_JOURNAL(page->mapping->host);
3349
3350         WARN_ON(PageChecked(page));
3351         if (!page_has_buffers(page))
3352                 return 0;
3353         if (journal)
3354                 return jbd2_journal_try_to_free_buffers(journal, page, wait);
3355         else
3356                 return try_to_free_buffers(page);
3357 }
3358
3359 /*
3360  * O_DIRECT for ext3 (or indirect map) based files
3361  *
3362  * If the O_DIRECT write will extend the file then add this inode to the
3363  * orphan list.  So recovery will truncate it back to the original size
3364  * if the machine crashes during the write.
3365  *
3366  * If the O_DIRECT write is intantiating holes inside i_size and the machine
3367  * crashes then stale disk data _may_ be exposed inside the file. But current
3368  * VFS code falls back into buffered path in that case so we are safe.
3369  */
3370 static ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb,
3371                               const struct iovec *iov, loff_t offset,
3372                               unsigned long nr_segs)
3373 {
3374         struct file *file = iocb->ki_filp;
3375         struct inode *inode = file->f_mapping->host;
3376         struct ext4_inode_info *ei = EXT4_I(inode);
3377         handle_t *handle;
3378         ssize_t ret;
3379         int orphan = 0;
3380         size_t count = iov_length(iov, nr_segs);
3381
3382         if (rw == WRITE) {
3383                 loff_t final_size = offset + count;
3384
3385                 if (final_size > inode->i_size) {
3386                         /* Credits for sb + inode write */
3387                         handle = ext4_journal_start(inode, 2);
3388                         if (IS_ERR(handle)) {
3389                                 ret = PTR_ERR(handle);
3390                                 goto out;
3391                         }
3392                         ret = ext4_orphan_add(handle, inode);
3393                         if (ret) {
3394                                 ext4_journal_stop(handle);
3395                                 goto out;
3396                         }
3397                         orphan = 1;
3398                         ei->i_disksize = inode->i_size;
3399                         ext4_journal_stop(handle);
3400                 }
3401         }
3402
3403         ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
3404                                  offset, nr_segs,
3405                                  ext4_get_block, NULL);
3406
3407         if (orphan) {
3408                 int err;
3409
3410                 /* Credits for sb + inode write */
3411                 handle = ext4_journal_start(inode, 2);
3412                 if (IS_ERR(handle)) {
3413                         /* This is really bad luck. We've written the data
3414                          * but cannot extend i_size. Bail out and pretend
3415                          * the write failed... */
3416                         ret = PTR_ERR(handle);
3417                         goto out;
3418                 }
3419                 if (inode->i_nlink)
3420                         ext4_orphan_del(handle, inode);
3421                 if (ret > 0) {
3422                         loff_t end = offset + ret;
3423                         if (end > inode->i_size) {
3424                                 ei->i_disksize = end;
3425                                 i_size_write(inode, end);
3426                                 /*
3427                                  * We're going to return a positive `ret'
3428                                  * here due to non-zero-length I/O, so there's
3429                                  * no way of reporting error returns from
3430                                  * ext4_mark_inode_dirty() to userspace.  So
3431                                  * ignore it.
3432                                  */
3433                                 ext4_mark_inode_dirty(handle, inode);
3434                         }
3435                 }
3436                 err = ext4_journal_stop(handle);
3437                 if (ret == 0)
3438                         ret = err;
3439         }
3440 out:
3441         return ret;
3442 }
3443
3444 /* Maximum number of blocks we map for direct IO at once. */
3445
3446 static int ext4_get_block_dio_write(struct inode *inode, sector_t iblock,
3447                    struct buffer_head *bh_result, int create)
3448 {
3449         handle_t *handle = NULL;
3450         int ret = 0;
3451         unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
3452         int dio_credits;
3453
3454         ext4_debug("ext4_get_block_dio_write: inode %lu, create flag %d\n",
3455                    inode->i_ino, create);
3456         /*
3457          * DIO VFS code passes create = 0 flag for write to
3458          * the middle of file. It does this to avoid block
3459          * allocation for holes, to prevent expose stale data
3460          * out when there is parallel buffered read (which does
3461          * not hold the i_mutex lock) while direct IO write has
3462          * not completed. DIO request on holes finally falls back
3463          * to buffered IO for this reason.
3464          *
3465          * For ext4 extent based file, since we support fallocate,
3466          * new allocated extent as uninitialized, for holes, we
3467          * could fallocate blocks for holes, thus parallel
3468          * buffered IO read will zero out the page when read on
3469          * a hole while parallel DIO write to the hole has not completed.
3470          *
3471          * when we come here, we know it's a direct IO write to
3472          * to the middle of file (<i_size)
3473          * so it's safe to override the create flag from VFS.
3474          */
3475         create = EXT4_GET_BLOCKS_DIO_CREATE_EXT;
3476
3477         if (max_blocks > DIO_MAX_BLOCKS)
3478                 max_blocks = DIO_MAX_BLOCKS;
3479         dio_credits = ext4_chunk_trans_blocks(inode, max_blocks);
3480         handle = ext4_journal_start(inode, dio_credits);
3481         if (IS_ERR(handle)) {
3482                 ret = PTR_ERR(handle);
3483                 goto out;
3484         }
3485         ret = ext4_get_blocks(handle, inode, iblock, max_blocks, bh_result,
3486                               create);
3487         if (ret > 0) {
3488                 bh_result->b_size = (ret << inode->i_blkbits);
3489                 ret = 0;
3490         }
3491         ext4_journal_stop(handle);
3492 out:
3493         return ret;
3494 }
3495
3496 static void ext4_free_io_end(ext4_io_end_t *io)
3497 {
3498         BUG_ON(!io);
3499         iput(io->inode);
3500         kfree(io);
3501 }
3502 static void dump_aio_dio_list(struct inode * inode)
3503 {
3504 #ifdef  EXT4_DEBUG
3505         struct list_head *cur, *before, *after;
3506         ext4_io_end_t *io, *io0, *io1;
3507
3508         if (list_empty(&EXT4_I(inode)->i_aio_dio_complete_list)){
3509                 ext4_debug("inode %lu aio dio list is empty\n", inode->i_ino);
3510                 return;
3511         }
3512
3513         ext4_debug("Dump inode %lu aio_dio_completed_IO list \n", inode->i_ino);
3514         list_for_each_entry(io, &EXT4_I(inode)->i_aio_dio_complete_list, list){
3515                 cur = &io->list;
3516                 before = cur->prev;
3517                 io0 = container_of(before, ext4_io_end_t, list);
3518                 after = cur->next;
3519                 io1 = container_of(after, ext4_io_end_t, list);
3520
3521                 ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n",
3522                             io, inode->i_ino, io0, io1);
3523         }
3524 #endif
3525 }
3526
3527 /*
3528  * check a range of space and convert unwritten extents to written.
3529  */
3530 static int ext4_end_aio_dio_nolock(ext4_io_end_t *io)
3531 {
3532         struct inode *inode = io->inode;
3533         loff_t offset = io->offset;
3534         size_t size = io->size;
3535         int ret = 0;
3536
3537         ext4_debug("end_aio_dio_onlock: io 0x%p from inode %lu,list->next 0x%p,"
3538                    "list->prev 0x%p\n",
3539                    io, inode->i_ino, io->list.next, io->list.prev);
3540
3541         if (list_empty(&io->list))
3542                 return ret;
3543
3544         if (io->flag != DIO_AIO_UNWRITTEN)
3545                 return ret;
3546
3547         if (offset + size <= i_size_read(inode))
3548                 ret = ext4_convert_unwritten_extents(inode, offset, size);
3549
3550         if (ret < 0) {
3551                 printk(KERN_EMERG "%s: failed to convert unwritten"
3552                         "extents to written extents, error is %d"
3553                         " io is still on inode %lu aio dio list\n",
3554                        __func__, ret, inode->i_ino);
3555                 return ret;
3556         }
3557
3558         /* clear the DIO AIO unwritten flag */
3559         io->flag = 0;
3560         return ret;
3561 }
3562 /*
3563  * work on completed aio dio IO, to convert unwritten extents to extents
3564  */
3565 static void ext4_end_aio_dio_work(struct work_struct *work)
3566 {
3567         ext4_io_end_t *io  = container_of(work, ext4_io_end_t, work);
3568         struct inode *inode = io->inode;
3569         int ret = 0;
3570
3571         mutex_lock(&inode->i_mutex);
3572         ret = ext4_end_aio_dio_nolock(io);
3573         if (ret >= 0) {
3574                 if (!list_empty(&io->list))
3575                         list_del_init(&io->list);
3576                 ext4_free_io_end(io);
3577         }
3578         mutex_unlock(&inode->i_mutex);
3579 }
3580 /*
3581  * This function is called from ext4_sync_file().
3582  *
3583  * When AIO DIO IO is completed, the work to convert unwritten
3584  * extents to written is queued on workqueue but may not get immediately
3585  * scheduled. When fsync is called, we need to ensure the
3586  * conversion is complete before fsync returns.
3587  * The inode keeps track of a list of completed AIO from DIO path
3588  * that might needs to do the conversion. This function walks through
3589  * the list and convert the related unwritten extents to written.
3590  */
3591 int flush_aio_dio_completed_IO(struct inode *inode)
3592 {
3593         ext4_io_end_t *io;
3594         int ret = 0;
3595         int ret2 = 0;
3596
3597         if (list_empty(&EXT4_I(inode)->i_aio_dio_complete_list))
3598                 return ret;
3599
3600         dump_aio_dio_list(inode);
3601         while (!list_empty(&EXT4_I(inode)->i_aio_dio_complete_list)){
3602                 io = list_entry(EXT4_I(inode)->i_aio_dio_complete_list.next,
3603                                 ext4_io_end_t, list);
3604                 /*
3605                  * Calling ext4_end_aio_dio_nolock() to convert completed
3606                  * IO to written.
3607                  *
3608                  * When ext4_sync_file() is called, run_queue() may already
3609                  * about to flush the work corresponding to this io structure.
3610                  * It will be upset if it founds the io structure related
3611                  * to the work-to-be schedule is freed.
3612                  *
3613                  * Thus we need to keep the io structure still valid here after
3614                  * convertion finished. The io structure has a flag to
3615                  * avoid double converting from both fsync and background work
3616                  * queue work.
3617                  */
3618                 ret = ext4_end_aio_dio_nolock(io);
3619                 if (ret < 0)
3620                         ret2 = ret;
3621                 else
3622                         list_del_init(&io->list);
3623         }
3624         return (ret2 < 0) ? ret2 : 0;
3625 }
3626
3627 static ext4_io_end_t *ext4_init_io_end (struct inode *inode)
3628 {
3629         ext4_io_end_t *io = NULL;
3630
3631         io = kmalloc(sizeof(*io), GFP_NOFS);
3632
3633         if (io) {
3634                 igrab(inode);
3635                 io->inode = inode;
3636                 io->flag = 0;
3637                 io->offset = 0;
3638                 io->size = 0;
3639                 io->error = 0;
3640                 INIT_WORK(&io->work, ext4_end_aio_dio_work);
3641                 INIT_LIST_HEAD(&io->list);
3642         }
3643
3644         return io;
3645 }
3646
3647 static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
3648                             ssize_t size, void *private)
3649 {
3650         ext4_io_end_t *io_end = iocb->private;
3651         struct workqueue_struct *wq;
3652
3653         ext_debug("ext4_end_io_dio(): io_end 0x%p"
3654                   "for inode %lu, iocb 0x%p, offset %llu, size %llu\n",
3655                   iocb->private, io_end->inode->i_ino, iocb, offset,
3656                   size);
3657         /* if not async direct IO or dio with 0 bytes write, just return */
3658         if (!io_end || !size)
3659                 return;
3660
3661         /* if not aio dio with unwritten extents, just free io and return */
3662         if (io_end->flag != DIO_AIO_UNWRITTEN){
3663                 ext4_free_io_end(io_end);
3664                 iocb->private = NULL;
3665                 return;
3666         }
3667
3668         io_end->offset = offset;
3669         io_end->size = size;
3670         wq = EXT4_SB(io_end->inode->i_sb)->dio_unwritten_wq;
3671
3672         /* queue the work to convert unwritten extents to written */
3673         queue_work(wq, &io_end->work);
3674
3675         /* Add the io_end to per-inode completed aio dio list*/
3676         list_add_tail(&io_end->list,
3677                  &EXT4_I(io_end->inode)->i_aio_dio_complete_list);
3678         iocb->private = NULL;
3679 }
3680 /*
3681  * For ext4 extent files, ext4 will do direct-io write to holes,
3682  * preallocated extents, and those write extend the file, no need to
3683  * fall back to buffered IO.
3684  *
3685  * For holes, we fallocate those blocks, mark them as unintialized
3686  * If those blocks were preallocated, we mark sure they are splited, but
3687  * still keep the range to write as unintialized.
3688  *
3689  * The unwrritten extents will be converted to written when DIO is completed.
3690  * For async direct IO, since the IO may still pending when return, we
3691  * set up an end_io call back function, which will do the convertion
3692  * when async direct IO completed.
3693  *
3694  * If the O_DIRECT write will extend the file then add this inode to the
3695  * orphan list.  So recovery will truncate it back to the original size
3696  * if the machine crashes during the write.
3697  *
3698  */
3699 static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
3700                               const struct iovec *iov, loff_t offset,
3701                               unsigned long nr_segs)
3702 {
3703         struct file *file = iocb->ki_filp;
3704         struct inode *inode = file->f_mapping->host;
3705         ssize_t ret;
3706         size_t count = iov_length(iov, nr_segs);
3707
3708         loff_t final_size = offset + count;
3709         if (rw == WRITE && final_size <= inode->i_size) {
3710                 /*
3711                  * We could direct write to holes and fallocate.
3712                  *
3713                  * Allocated blocks to fill the hole are marked as uninitialized
3714                  * to prevent paralel buffered read to expose the stale data
3715                  * before DIO complete the data IO.
3716                  *
3717                  * As to previously fallocated extents, ext4 get_block
3718                  * will just simply mark the buffer mapped but still
3719                  * keep the extents uninitialized.
3720                  *
3721                  * for non AIO case, we will convert those unwritten extents
3722                  * to written after return back from blockdev_direct_IO.
3723                  *
3724                  * for async DIO, the conversion needs to be defered when
3725                  * the IO is completed. The ext4 end_io callback function
3726                  * will be called to take care of the conversion work.
3727                  * Here for async case, we allocate an io_end structure to
3728                  * hook to the iocb.
3729                  */
3730                 iocb->private = NULL;
3731                 EXT4_I(inode)->cur_aio_dio = NULL;
3732                 if (!is_sync_kiocb(iocb)) {
3733                         iocb->private = ext4_init_io_end(inode);
3734                         if (!iocb->private)
3735                                 return -ENOMEM;
3736                         /*
3737                          * we save the io structure for current async
3738                          * direct IO, so that later ext4_get_blocks()
3739                          * could flag the io structure whether there
3740                          * is a unwritten extents needs to be converted
3741                          * when IO is completed.
3742                          */
3743                         EXT4_I(inode)->cur_aio_dio = iocb->private;
3744                 }
3745
3746                 ret = blockdev_direct_IO(rw, iocb, inode,
3747                                          inode->i_sb->s_bdev, iov,
3748                                          offset, nr_segs,
3749                                          ext4_get_block_dio_write,
3750                                          ext4_end_io_dio);
3751                 if (iocb->private)
3752                         EXT4_I(inode)->cur_aio_dio = NULL;
3753                 /*
3754                  * The io_end structure takes a reference to the inode,
3755                  * that structure needs to be destroyed and the
3756                  * reference to the inode need to be dropped, when IO is
3757                  * complete, even with 0 byte write, or failed.
3758                  *
3759                  * In the successful AIO DIO case, the io_end structure will be
3760                  * desctroyed and the reference to the inode will be dropped
3761                  * after the end_io call back function is called.
3762                  *
3763                  * In the case there is 0 byte write, or error case, since
3764                  * VFS direct IO won't invoke the end_io call back function,
3765                  * we need to free the end_io structure here.
3766                  */
3767                 if (ret != -EIOCBQUEUED && ret <= 0 && iocb->private) {
3768                         ext4_free_io_end(iocb->private);
3769                         iocb->private = NULL;
3770                 } else if (ret > 0)
3771                         /*
3772                          * for non AIO case, since the IO is already
3773                          * completed, we could do the convertion right here
3774                          */
3775                         ret = ext4_convert_unwritten_extents(inode,
3776                                                                 offset, ret);
3777                 return ret;
3778         }
3779
3780         /* for write the the end of file case, we fall back to old way */
3781         return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
3782 }
3783
3784 static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
3785                               const struct iovec *iov, loff_t offset,
3786                               unsigned long nr_segs)
3787 {
3788         struct file *file = iocb->ki_filp;
3789         struct inode *inode = file->f_mapping->host;
3790
3791         if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
3792                 return ext4_ext_direct_IO(rw, iocb, iov, offset, nr_segs);
3793
3794         return ext4_ind_direct_IO(rw, iocb, iov, offset, nr_segs);
3795 }
3796
3797 /*
3798  * Pages can be marked dirty completely asynchronously from ext4's journalling
3799  * activity.  By filemap_sync_pte(), try_to_unmap_one(), etc.  We cannot do
3800  * much here because ->set_page_dirty is called under VFS locks.  The page is
3801  * not necessarily locked.
3802  *
3803  * We cannot just dirty the page and leave attached buffers clean, because the
3804  * buffers' dirty state is "definitive".  We cannot just set the buffers dirty
3805  * or jbddirty because all the journalling code will explode.
3806  *
3807  * So what we do is to mark the page "pending dirty" and next time writepage
3808  * is called, propagate that into the buffers appropriately.
3809  */
3810 static int ext4_journalled_set_page_dirty(struct page *page)
3811 {
3812         SetPageChecked(page);
3813         return __set_page_dirty_nobuffers(page);
3814 }
3815
3816 static const struct address_space_operations ext4_ordered_aops = {
3817         .readpage               = ext4_readpage,
3818         .readpages              = ext4_readpages,
3819         .writepage              = ext4_writepage,
3820         .sync_page              = block_sync_page,
3821         .write_begin            = ext4_write_begin,
3822         .write_end              = ext4_ordered_write_end,
3823         .bmap                   = ext4_bmap,
3824         .invalidatepage         = ext4_invalidatepage,
3825         .releasepage            = ext4_releasepage,
3826         .direct_IO              = ext4_direct_IO,
3827         .migratepage            = buffer_migrate_page,
3828         .is_partially_uptodate  = block_is_partially_uptodate,
3829         .error_remove_page      = generic_error_remove_page,
3830 };
3831
3832 static const struct address_space_operations ext4_writeback_aops = {
3833         .readpage               = ext4_readpage,
3834         .readpages              = ext4_readpages,
3835         .writepage              = ext4_writepage,
3836         .sync_page              = block_sync_page,
3837         .write_begin            = ext4_write_begin,
3838         .write_end              = ext4_writeback_write_end,
3839         .bmap                   = ext4_bmap,
3840         .invalidatepage         = ext4_invalidatepage,
3841         .releasepage            = ext4_releasepage,
3842         .direct_IO              = ext4_direct_IO,
3843         .migratepage            = buffer_migrate_page,
3844         .is_partially_uptodate  = block_is_partially_uptodate,
3845         .error_remove_page      = generic_error_remove_page,
3846 };
3847
3848 static const struct address_space_operations ext4_journalled_aops = {
3849         .readpage               = ext4_readpage,
3850         .readpages              = ext4_readpages,
3851         .writepage              = ext4_writepage,
3852         .sync_page              = block_sync_page,
3853         .write_begin            = ext4_write_begin,
3854         .write_end              = ext4_journalled_write_end,
3855         .set_page_dirty         = ext4_journalled_set_page_dirty,
3856         .bmap                   = ext4_bmap,
3857         .invalidatepage         = ext4_invalidatepage,
3858         .releasepage            = ext4_releasepage,
3859         .is_partially_uptodate  = block_is_partially_uptodate,
3860         .error_remove_page      = generic_error_remove_page,
3861 };
3862
3863 static const struct address_space_operations ext4_da_aops = {
3864         .readpage               = ext4_readpage,
3865         .readpages              = ext4_readpages,
3866         .writepage              = ext4_writepage,
3867         .writepages             = ext4_da_writepages,
3868         .sync_page              = block_sync_page,
3869         .write_begin            = ext4_da_write_begin,
3870         .write_end              = ext4_da_write_end,
3871         .bmap                   = ext4_bmap,
3872         .invalidatepage         = ext4_da_invalidatepage,
3873         .releasepage            = ext4_releasepage,
3874         .direct_IO              = ext4_direct_IO,
3875         .migratepage            = buffer_migrate_page,
3876         .is_partially_uptodate  = block_is_partially_uptodate,
3877         .error_remove_page      = generic_error_remove_page,
3878 };
3879
3880 void ext4_set_aops(struct inode *inode)
3881 {
3882         if (ext4_should_order_data(inode) &&
3883                 test_opt(inode->i_sb, DELALLOC))
3884                 inode->i_mapping->a_ops = &ext4_da_aops;
3885         else if (ext4_should_order_data(inode))
3886                 inode->i_mapping->a_ops = &ext4_ordered_aops;
3887         else if (ext4_should_writeback_data(inode) &&
3888                  test_opt(inode->i_sb, DELALLOC))
3889                 inode->i_mapping->a_ops = &ext4_da_aops;
3890         else if (ext4_should_writeback_data(inode))
3891                 inode->i_mapping->a_ops = &ext4_writeback_aops;
3892         else
3893                 inode->i_mapping->a_ops = &ext4_journalled_aops;
3894 }
3895
3896 /*
3897  * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
3898  * up to the end of the block which corresponds to `from'.
3899  * This required during truncate. We need to physically zero the tail end
3900  * of that block so it doesn't yield old data if the file is later grown.
3901  */
3902 int ext4_block_truncate_page(handle_t *handle,
3903                 struct address_space *mapping, loff_t from)
3904 {
3905         ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
3906         unsigned offset = from & (PAGE_CACHE_SIZE-1);
3907         unsigned blocksize, length, pos;
3908         ext4_lblk_t iblock;
3909         struct inode *inode = mapping->host;
3910         struct buffer_head *bh;
3911         struct page *page;
3912         int err = 0;
3913
3914         page = find_or_create_page(mapping, from >> PAGE_CACHE_SHIFT,
3915                                    mapping_gfp_mask(mapping) & ~__GFP_FS);
3916         if (!page)
3917                 return -EINVAL;
3918
3919         blocksize = inode->i_sb->s_blocksize;
3920         length = blocksize - (offset & (blocksize - 1));
3921         iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
3922
3923         /*
3924          * For "nobh" option,  we can only work if we don't need to
3925          * read-in the page - otherwise we create buffers to do the IO.
3926          */
3927         if (!page_has_buffers(page) && test_opt(inode->i_sb, NOBH) &&
3928              ext4_should_writeback_data(inode) && PageUptodate(page)) {
3929                 zero_user(page, offset, length);
3930                 set_page_dirty(page);
3931                 goto unlock;
3932         }
3933
3934         if (!page_has_buffers(page))
3935                 create_empty_buffers(page, blocksize, 0);
3936
3937         /* Find the buffer that contains "offset" */
3938         bh = page_buffers(page);
3939         pos = blocksize;
3940         while (offset >= pos) {
3941                 bh = bh->b_this_page;
3942                 iblock++;
3943                 pos += blocksize;
3944         }
3945
3946         err = 0;
3947         if (buffer_freed(bh)) {
3948                 BUFFER_TRACE(bh, "freed: skip");
3949                 goto unlock;
3950         }
3951
3952         if (!buffer_mapped(bh)) {
3953                 BUFFER_TRACE(bh, "unmapped");
3954                 ext4_get_block(inode, iblock, bh, 0);
3955                 /* unmapped? It's a hole - nothing to do */
3956                 if (!buffer_mapped(bh)) {
3957                         BUFFER_TRACE(bh, "still unmapped");
3958                         goto unlock;
3959                 }
3960         }
3961
3962         /* Ok, it's mapped. Make sure it's up-to-date */
3963         if (PageUptodate(page))
3964                 set_buffer_uptodate(bh);
3965
3966         if (!buffer_uptodate(bh)) {
3967                 err = -EIO;
3968                 ll_rw_block(READ, 1, &bh);
3969                 wait_on_buffer(bh);
3970                 /* Uhhuh. Read error. Complain and punt. */
3971                 if (!buffer_uptodate(bh))
3972                         goto unlock;
3973         }
3974
3975         if (ext4_should_journal_data(inode)) {
3976                 BUFFER_TRACE(bh, "get write access");
3977                 err = ext4_journal_get_write_access(handle, bh);
3978                 if (err)
3979                         goto unlock;
3980         }
3981
3982         zero_user(page, offset, length);
3983
3984         BUFFER_TRACE(bh, "zeroed end of block");
3985
3986         err = 0;
3987         if (ext4_should_journal_data(inode)) {
3988                 err = ext4_handle_dirty_metadata(handle, inode, bh);
3989         } else {
3990                 if (ext4_should_order_data(inode))
3991                         err = ext4_jbd2_file_inode(handle, inode);
3992                 mark_buffer_dirty(bh);
3993         }
3994
3995 unlock:
3996         unlock_page(page);
3997         page_cache_release(page);
3998         return err;
3999 }
4000
4001 /*
4002  * Probably it should be a library function... search for first non-zero word
4003  * or memcmp with zero_page, whatever is better for particular architecture.
4004  * Linus?
4005  */
4006 static inline int all_zeroes(__le32 *p, __le32 *q)
4007 {
4008         while (p < q)
4009                 if (*p++)
4010                         return 0;
4011         return 1;
4012 }
4013
4014 /**
4015  *      ext4_find_shared - find the indirect blocks for partial truncation.
4016  *      @inode:   inode in question
4017  *      @depth:   depth of the affected branch
4018  *      @offsets: offsets of pointers in that branch (see ext4_block_to_path)
4019  *      @chain:   place to store the pointers to partial indirect blocks
4020  *      @top:     place to the (detached) top of branch
4021  *
4022  *      This is a helper function used by ext4_truncate().
4023  *
4024  *      When we do truncate() we may have to clean the ends of several
4025  *      indirect blocks but leave the blocks themselves alive. Block is
4026  *      partially truncated if some data below the new i_size is refered
4027  *      from it (and it is on the path to the first completely truncated
4028  *      data block, indeed).  We have to free the top of that path along
4029  *      with everything to the right of the path. Since no allocation
4030  *      past the truncation point is possible until ext4_truncate()
4031  *      finishes, we may safely do the latter, but top of branch may
4032  *      require special attention - pageout below the truncation point
4033  *      might try to populate it.
4034  *
4035  *      We atomically detach the top of branch from the tree, store the
4036  *      block number of its root in *@top, pointers to buffer_heads of
4037  *      partially truncated blocks - in @chain[].bh and pointers to
4038  *      their last elements that should not be removed - in
4039  *      @chain[].p. Return value is the pointer to last filled element
4040  *      of @chain.
4041  *
4042  *      The work left to caller to do the actual freeing of subtrees:
4043  *              a) free the subtree starting from *@top
4044  *              b) free the subtrees whose roots are stored in
4045  *                      (@chain[i].p+1 .. end of @chain[i].bh->b_data)
4046  *              c) free the subtrees growing from the inode past the @chain[0].
4047  *                      (no partially truncated stuff there).  */
4048
4049 static Indirect *ext4_find_shared(struct inode *inode, int depth,
4050                                   ext4_lblk_t offsets[4], Indirect chain[4],
4051                                   __le32 *top)
4052 {
4053         Indirect *partial, *p;
4054         int k, err;
4055
4056         *top = 0;
4057         /* Make k index the deepest non-null offest + 1 */
4058         for (k = depth; k > 1 && !offsets[k-1]; k--)
4059                 ;
4060         partial = ext4_get_branch(inode, k, offsets, chain, &err);
4061         /* Writer: pointers */
4062         if (!partial)
4063                 partial = chain + k-1;
4064         /*
4065          * If the branch acquired continuation since we've looked at it -
4066          * fine, it should all survive and (new) top doesn't belong to us.
4067          */
4068         if (!partial->key && *partial->p)
4069                 /* Writer: end */
4070                 goto no_top;
4071         for (p = partial; (p > chain) && all_zeroes((__le32 *) p->bh->b_data, p->p); p--)
4072                 ;
4073         /*
4074          * OK, we've found the last block that must survive. The rest of our
4075          * branch should be detached before unlocking. However, if that rest
4076          * of branch is all ours and does not grow immediately from the inode
4077          * it's easier to cheat and just decrement partial->p.
4078          */
4079         if (p == chain + k - 1 && p > chain) {
4080                 p->p--;
4081         } else {
4082                 *top = *p->p;
4083                 /* Nope, don't do this in ext4.  Must leave the tree intact */
4084 #if 0
4085                 *p->p = 0;
4086 #endif
4087         }
4088         /* Writer: end */
4089
4090         while (partial > p) {
4091                 brelse(partial->bh);
4092                 partial--;
4093         }
4094 no_top:
4095         return partial;
4096 }
4097
4098 /*
4099  * Zero a number of block pointers in either an inode or an indirect block.
4100  * If we restart the transaction we must again get write access to the
4101  * indirect block for further modification.
4102  *
4103  * We release `count' blocks on disk, but (last - first) may be greater
4104  * than `count' because there can be holes in there.
4105  */
4106 static void ext4_clear_blocks(handle_t *handle, struct inode *inode,
4107                               struct buffer_head *bh,
4108                               ext4_fsblk_t block_to_free,
4109                               unsigned long count, __le32 *first,
4110                               __le32 *last)
4111 {
4112         __le32 *p;
4113         if (try_to_extend_transaction(handle, inode)) {
4114                 if (bh) {
4115                         BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
4116                         ext4_handle_dirty_metadata(handle, inode, bh);
4117                 }
4118                 ext4_mark_inode_dirty(handle, inode);
4119                 ext4_truncate_restart_trans(handle, inode,
4120                                             blocks_for_truncate(inode));
4121                 if (bh) {
4122                         BUFFER_TRACE(bh, "retaking write access");
4123                         ext4_journal_get_write_access(handle, bh);
4124                 }
4125         }
4126
4127         /*
4128          * Any buffers which are on the journal will be in memory. We
4129          * find them on the hash table so jbd2_journal_revoke() will
4130          * run jbd2_journal_forget() on them.  We've already detached
4131          * each block from the file, so bforget() in
4132          * jbd2_journal_forget() should be safe.
4133          *
4134          * AKPM: turn on bforget in jbd2_journal_forget()!!!
4135          */
4136         for (p = first; p < last; p++) {
4137                 u32 nr = le32_to_cpu(*p);
4138                 if (nr) {
4139                         struct buffer_head *tbh;
4140
4141                         *p = 0;
4142                         tbh = sb_find_get_block(inode->i_sb, nr);
4143                         ext4_forget(handle, 0, inode, tbh, nr);
4144                 }
4145         }
4146
4147         ext4_free_blocks(handle, inode, block_to_free, count, 0);
4148 }
4149
4150 /**
4151  * ext4_free_data - free a list of data blocks
4152  * @handle:     handle for this transaction
4153  * @inode:      inode we are dealing with
4154  * @this_bh:    indirect buffer_head which contains *@first and *@last
4155  * @first:      array of block numbers
4156  * @last:       points immediately past the end of array
4157  *
4158  * We are freeing all blocks refered from that array (numbers are stored as
4159  * little-endian 32-bit) and updating @inode->i_blocks appropriately.
4160  *
4161  * We accumulate contiguous runs of blocks to free.  Conveniently, if these
4162  * blocks are contiguous then releasing them at one time will only affect one
4163  * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
4164  * actually use a lot of journal space.
4165  *
4166  * @this_bh will be %NULL if @first and @last point into the inode's direct
4167  * block pointers.
4168  */
4169 static void ext4_free_data(handle_t *handle, struct inode *inode,
4170                            struct buffer_head *this_bh,
4171                            __le32 *first, __le32 *last)
4172 {
4173         ext4_fsblk_t block_to_free = 0;    /* Starting block # of a run */
4174         unsigned long count = 0;            /* Number of blocks in the run */
4175         __le32 *block_to_free_p = NULL;     /* Pointer into inode/ind
4176                                                corresponding to
4177                                                block_to_free */
4178         ext4_fsblk_t nr;                    /* Current block # */
4179         __le32 *p;                          /* Pointer into inode/ind
4180                                                for current block */
4181         int err;
4182
4183         if (this_bh) {                          /* For indirect block */
4184                 BUFFER_TRACE(this_bh, "get_write_access");
4185                 err = ext4_journal_get_write_access(handle, this_bh);
4186                 /* Important: if we can't update the indirect pointers
4187                  * to the blocks, we can't free them. */
4188                 if (err)
4189                         return;
4190         }
4191
4192         for (p = first; p < last; p++) {
4193                 nr = le32_to_cpu(*p);
4194                 if (nr) {
4195                         /* accumulate blocks to free if they're contiguous */
4196                         if (count == 0) {
4197                                 block_to_free = nr;
4198                                 block_to_free_p = p;
4199                                 count = 1;
4200                         } else if (nr == block_to_free + count) {
4201                                 count++;
4202                         } else {
4203                                 ext4_clear_blocks(handle, inode, this_bh,
4204                                                   block_to_free,
4205                                                   count, block_to_free_p, p);
4206                                 block_to_free = nr;
4207                                 block_to_free_p = p;
4208                                 count = 1;
4209                         }
4210                 }
4211         }
4212
4213         if (count > 0)
4214                 ext4_clear_blocks(handle, inode, this_bh, block_to_free,
4215                                   count, block_to_free_p, p);
4216
4217         if (this_bh) {
4218                 BUFFER_TRACE(this_bh, "call ext4_handle_dirty_metadata");
4219
4220                 /*
4221                  * The buffer head should have an attached journal head at this
4222                  * point. However, if the data is corrupted and an indirect
4223                  * block pointed to itself, it would have been detached when
4224                  * the block was cleared. Check for this instead of OOPSing.
4225                  */
4226                 if ((EXT4_JOURNAL(inode) == NULL) || bh2jh(this_bh))
4227                         ext4_handle_dirty_metadata(handle, inode, this_bh);
4228                 else
4229                         ext4_error(inode->i_sb, __func__,
4230                                    "circular indirect block detected, "
4231                                    "inode=%lu, block=%llu",
4232                                    inode->i_ino,
4233                                    (unsigned long long) this_bh->b_blocknr);
4234         }
4235 }
4236
4237 /**
4238  *      ext4_free_branches - free an array of branches
4239  *      @handle: JBD handle for this transaction
4240  *      @inode: inode we are dealing with
4241  *      @parent_bh: the buffer_head which contains *@first and *@last
4242  *      @first: array of block numbers
4243  *      @last:  pointer immediately past the end of array
4244  *      @depth: depth of the branches to free
4245  *
4246  *      We are freeing all blocks refered from these branches (numbers are
4247  *      stored as little-endian 32-bit) and updating @inode->i_blocks
4248  *      appropriately.
4249  */
4250 static void ext4_free_branches(handle_t *handle, struct inode *inode,
4251                                struct buffer_head *parent_bh,
4252                                __le32 *first, __le32 *last, int depth)
4253 {
4254         ext4_fsblk_t nr;
4255         __le32 *p;
4256
4257         if (ext4_handle_is_aborted(handle))
4258                 return;
4259
4260         if (depth--) {
4261                 struct buffer_head *bh;
4262                 int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
4263                 p = last;
4264                 while (--p >= first) {
4265                         nr = le32_to_cpu(*p);
4266                         if (!nr)
4267                                 continue;               /* A hole */
4268
4269                         /* Go read the buffer for the next level down */
4270                         bh = sb_bread(inode->i_sb, nr);
4271
4272                         /*
4273                          * A read failure? Report error and clear slot
4274                          * (should be rare).
4275                          */
4276                         if (!bh) {
4277                                 ext4_error(inode->i_sb, "ext4_free_branches",
4278                                            "Read failure, inode=%lu, block=%llu",
4279                                            inode->i_ino, nr);
4280                                 continue;
4281                         }
4282
4283                         /* This zaps the entire block.  Bottom up. */
4284                         BUFFER_TRACE(bh, "free child branches");
4285                         ext4_free_branches(handle, inode, bh,
4286                                         (__le32 *) bh->b_data,
4287                                         (__le32 *) bh->b_data + addr_per_block,
4288                                         depth);
4289
4290                         /*
4291                          * We've probably journalled the indirect block several
4292                          * times during the truncate.  But it's no longer
4293                          * needed and we now drop it from the transaction via
4294                          * jbd2_journal_revoke().
4295                          *
4296                          * That's easy if it's exclusively part of this
4297                          * transaction.  But if it's part of the committing
4298                          * transaction then jbd2_journal_forget() will simply
4299                          * brelse() it.  That means that if the underlying
4300                          * block is reallocated in ext4_get_block(),
4301                          * unmap_underlying_metadata() will find this block
4302                          * and will try to get rid of it.  damn, damn.
4303                          *
4304                          * If this block has already been committed to the
4305                          * journal, a revoke record will be written.  And
4306                          * revoke records must be emitted *before* clearing
4307                          * this block's bit in the bitmaps.
4308                          */
4309                         ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
4310
4311                         /*
4312                          * Everything below this this pointer has been
4313                          * released.  Now let this top-of-subtree go.
4314                          *
4315                          * We want the freeing of this indirect block to be
4316                          * atomic in the journal with the updating of the
4317                          * bitmap block which owns it.  So make some room in
4318                          * the journal.
4319                          *
4320                          * We zero the parent pointer *after* freeing its
4321                          * pointee in the bitmaps, so if extend_transaction()
4322                          * for some reason fails to put the bitmap changes and
4323                          * the release into the same transaction, recovery
4324                          * will merely complain about releasing a free block,
4325                          * rather than leaking blocks.
4326                          */
4327                         if (ext4_handle_is_aborted(handle))
4328                                 return;
4329                         if (try_to_extend_transaction(handle, inode)) {
4330                                 ext4_mark_inode_dirty(handle, inode);
4331                                 ext4_truncate_restart_trans(handle, inode,
4332                                             blocks_for_truncate(inode));
4333                         }
4334
4335                         ext4_free_blocks(handle, inode, nr, 1, 1);
4336
4337                         if (parent_bh) {
4338                                 /*
4339                                  * The block which we have just freed is
4340                                  * pointed to by an indirect block: journal it
4341                                  */
4342                                 BUFFER_TRACE(parent_bh, "get_write_access");
4343                                 if (!ext4_journal_get_write_access(handle,
4344                                                                    parent_bh)){
4345                                         *p = 0;
4346                                         BUFFER_TRACE(parent_bh,
4347                                         "call ext4_handle_dirty_metadata");
4348                                         ext4_handle_dirty_metadata(handle,
4349                                                                    inode,
4350                                                                    parent_bh);
4351                                 }
4352                         }
4353                 }
4354         } else {
4355                 /* We have reached the bottom of the tree. */
4356                 BUFFER_TRACE(parent_bh, "free data blocks");
4357                 ext4_free_data(handle, inode, parent_bh, first, last);
4358         }
4359 }
4360
4361 int ext4_can_truncate(struct inode *inode)
4362 {
4363         if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
4364                 return 0;
4365         if (S_ISREG(inode->i_mode))
4366                 return 1;
4367         if (S_ISDIR(inode->i_mode))
4368                 return 1;
4369         if (S_ISLNK(inode->i_mode))
4370                 return !ext4_inode_is_fast_symlink(inode);
4371         return 0;
4372 }
4373
4374 /*
4375  * ext4_truncate()
4376  *
4377  * We block out ext4_get_block() block instantiations across the entire
4378  * transaction, and VFS/VM ensures that ext4_truncate() cannot run
4379  * simultaneously on behalf of the same inode.
4380  *
4381  * As we work through the truncate and commmit bits of it to the journal there
4382  * is one core, guiding principle: the file's tree must always be consistent on
4383  * disk.  We must be able to restart the truncate after a crash.
4384  *
4385  * The file's tree may be transiently inconsistent in memory (although it
4386  * probably isn't), but whenever we close off and commit a journal transaction,
4387  * the contents of (the filesystem + the journal) must be consistent and
4388  * restartable.  It's pretty simple, really: bottom up, right to left (although
4389  * left-to-right works OK too).
4390  *
4391  * Note that at recovery time, journal replay occurs *before* the restart of
4392  * truncate against the orphan inode list.
4393  *
4394  * The committed inode has the new, desired i_size (which is the same as
4395  * i_disksize in this case).  After a crash, ext4_orphan_cleanup() will see
4396  * that this inode's truncate did not complete and it will again call
4397  * ext4_truncate() to have another go.  So there will be instantiated blocks
4398  * to the right of the truncation point in a crashed ext4 filesystem.  But
4399  * that's fine - as long as they are linked from the inode, the post-crash
4400  * ext4_truncate() run will find them and release them.
4401  */
4402 void ext4_truncate(struct inode *inode)
4403 {
4404         handle_t *handle;
4405         struct ext4_inode_info *ei = EXT4_I(inode);
4406         __le32 *i_data = ei->i_data;
4407         int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
4408         struct address_space *mapping = inode->i_mapping;
4409         ext4_lblk_t offsets[4];
4410         Indirect chain[4];
4411         Indirect *partial;
4412         __le32 nr = 0;
4413         int n;
4414         ext4_lblk_t last_block;
4415         unsigned blocksize = inode->i_sb->s_blocksize;
4416
4417         if (!ext4_can_truncate(inode))
4418                 return;
4419
4420         if (inode->i_size == 0 && !test_opt(inode->i_sb, NO_AUTO_DA_ALLOC))
4421                 ei->i_state |= EXT4_STATE_DA_ALLOC_CLOSE;
4422
4423         if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
4424                 ext4_ext_truncate(inode);
4425                 return;
4426         }
4427
4428         handle = start_transaction(inode);
4429         if (IS_ERR(handle))
4430                 return;         /* AKPM: return what? */
4431
4432         last_block = (inode->i_size + blocksize-1)
4433                                         >> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
4434
4435         if (inode->i_size & (blocksize - 1))
4436                 if (ext4_block_truncate_page(handle, mapping, inode->i_size))
4437                         goto out_stop;
4438
4439         n = ext4_block_to_path(inode, last_block, offsets, NULL);
4440         if (n == 0)
4441                 goto out_stop;  /* error */
4442
4443         /*
4444          * OK.  This truncate is going to happen.  We add the inode to the
4445          * orphan list, so that if this truncate spans multiple transactions,
4446          * and we crash, we will resume the truncate when the filesystem
4447          * recovers.  It also marks the inode dirty, to catch the new size.
4448          *
4449          * Implication: the file must always be in a sane, consistent
4450          * truncatable state while each transaction commits.
4451          */
4452         if (ext4_orphan_add(handle, inode))
4453                 goto out_stop;
4454
4455         /*
4456          * From here we block out all ext4_get_block() callers who want to
4457          * modify the block allocation tree.
4458          */
4459         down_write(&ei->i_data_sem);
4460
4461         ext4_discard_preallocations(inode);
4462
4463         /*
4464          * The orphan list entry will now protect us from any crash which
4465          * occurs before the truncate completes, so it is now safe to propagate
4466          * the new, shorter inode size (held for now in i_size) into the
4467          * on-disk inode. We do this via i_disksize, which is the value which
4468          * ext4 *really* writes onto the disk inode.
4469          */
4470         ei->i_disksize = inode->i_size;
4471
4472         if (n == 1) {           /* direct blocks */
4473                 ext4_free_data(handle, inode, NULL, i_data+offsets[0],
4474                                i_data + EXT4_NDIR_BLOCKS);
4475                 goto do_indirects;
4476         }
4477
4478         partial = ext4_find_shared(inode, n, offsets, chain, &nr);
4479         /* Kill the top of shared branch (not detached) */
4480         if (nr) {
4481                 if (partial == chain) {
4482                         /* Shared branch grows from the inode */
4483                         ext4_free_branches(handle, inode, NULL,
4484                                            &nr, &nr+1, (chain+n-1) - partial);
4485                         *partial->p = 0;
4486                         /*
4487                          * We mark the inode dirty prior to restart,
4488                          * and prior to stop.  No need for it here.
4489                          */
4490                 } else {
4491                         /* Shared branch grows from an indirect block */
4492                         BUFFER_TRACE(partial->bh, "get_write_access");
4493                         ext4_free_branches(handle, inode, partial->bh,
4494                                         partial->p,
4495                                         partial->p+1, (chain+n-1) - partial);
4496                 }
4497         }
4498         /* Clear the ends of indirect blocks on the shared branch */
4499         while (partial > chain) {
4500                 ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
4501                                    (__le32*)partial->bh->b_data+addr_per_block,
4502                                    (chain+n-1) - partial);
4503                 BUFFER_TRACE(partial->bh, "call brelse");
4504                 brelse(partial->bh);
4505                 partial--;
4506         }
4507 do_indirects:
4508         /* Kill the remaining (whole) subtrees */
4509         switch (offsets[0]) {
4510         default:
4511                 nr = i_data[EXT4_IND_BLOCK];
4512                 if (nr) {
4513                         ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
4514                         i_data[EXT4_IND_BLOCK] = 0;
4515                 }
4516         case EXT4_IND_BLOCK:
4517                 nr = i_data[EXT4_DIND_BLOCK];
4518                 if (nr) {
4519                         ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
4520                         i_data[EXT4_DIND_BLOCK] = 0;
4521                 }
4522         case EXT4_DIND_BLOCK:
4523                 nr = i_data[EXT4_TIND_BLOCK];
4524                 if (nr) {
4525                         ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
4526                         i_data[EXT4_TIND_BLOCK] = 0;
4527                 }
4528         case EXT4_TIND_BLOCK:
4529                 ;
4530         }
4531
4532         up_write(&ei->i_data_sem);
4533         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
4534         ext4_mark_inode_dirty(handle, inode);
4535
4536         /*
4537          * In a multi-transaction truncate, we only make the final transaction
4538          * synchronous
4539          */
4540         if (IS_SYNC(inode))
4541                 ext4_handle_sync(handle);
4542 out_stop:
4543         /*
4544          * If this was a simple ftruncate(), and the file will remain alive
4545          * then we need to clear up the orphan record which we created above.
4546          * However, if this was a real unlink then we were called by
4547          * ext4_delete_inode(), and we allow that function to clean up the
4548          * orphan info for us.
4549          */
4550         if (inode->i_nlink)
4551                 ext4_orphan_del(handle, inode);
4552
4553         ext4_journal_stop(handle);
4554 }
4555
4556 /*
4557  * ext4_get_inode_loc returns with an extra refcount against the inode's
4558  * underlying buffer_head on success. If 'in_mem' is true, we have all
4559  * data in memory that is needed to recreate the on-disk version of this
4560  * inode.
4561  */
4562 static int __ext4_get_inode_loc(struct inode *inode,
4563                                 struct ext4_iloc *iloc, int in_mem)
4564 {
4565         struct ext4_group_desc  *gdp;
4566         struct buffer_head      *bh;
4567         struct super_block      *sb = inode->i_sb;
4568         ext4_fsblk_t            block;
4569         int                     inodes_per_block, inode_offset;
4570
4571         iloc->bh = NULL;
4572         if (!ext4_valid_inum(sb, inode->i_ino))
4573                 return -EIO;
4574
4575         iloc->block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
4576         gdp = ext4_get_group_desc(sb, iloc->block_group, NULL);
4577         if (!gdp)
4578                 return -EIO;
4579
4580         /*
4581          * Figure out the offset within the block group inode table
4582          */
4583         inodes_per_block = (EXT4_BLOCK_SIZE(sb) / EXT4_INODE_SIZE(sb));
4584         inode_offset = ((inode->i_ino - 1) %
4585                         EXT4_INODES_PER_GROUP(sb));
4586         block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block);
4587         iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
4588
4589         bh = sb_getblk(sb, block);
4590         if (!bh) {
4591                 ext4_error(sb, "ext4_get_inode_loc", "unable to read "
4592                            "inode block - inode=%lu, block=%llu",
4593                            inode->i_ino, block);
4594                 return -EIO;
4595         }
4596         if (!buffer_uptodate(bh)) {
4597                 lock_buffer(bh);
4598
4599                 /*
4600                  * If the buffer has the write error flag, we have failed
4601                  * to write out another inode in the same block.  In this
4602                  * case, we don't have to read the block because we may
4603                  * read the old inode data successfully.
4604                  */
4605                 if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
4606                         set_buffer_uptodate(bh);
4607
4608                 if (buffer_uptodate(bh)) {
4609                         /* someone brought it uptodate while we waited */
4610                         unlock_buffer(bh);
4611                         goto has_buffer;
4612                 }
4613
4614                 /*
4615                  * If we have all information of the inode in memory and this
4616                  * is the only valid inode in the block, we need not read the
4617                  * block.
4618                  */
4619                 if (in_mem) {
4620                         struct buffer_head *bitmap_bh;
4621                         int i, start;
4622
4623                         start = inode_offset & ~(inodes_per_block - 1);
4624
4625                         /* Is the inode bitmap in cache? */
4626                         bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
4627                         if (!bitmap_bh)
4628                                 goto make_io;
4629
4630                         /*
4631                          * If the inode bitmap isn't in cache then the
4632                          * optimisation may end up performing two reads instead
4633                          * of one, so skip it.
4634                          */
4635                         if (!buffer_uptodate(bitmap_bh)) {
4636                                 brelse(bitmap_bh);
4637                                 goto make_io;
4638                         }
4639                         for (i = start; i < start + inodes_per_block; i++) {
4640                                 if (i == inode_offset)
4641                                         continue;
4642                                 if (ext4_test_bit(i, bitmap_bh->b_data))
4643                                         break;
4644                         }
4645                         brelse(bitmap_bh);
4646                         if (i == start + inodes_per_block) {
4647                                 /* all other inodes are free, so skip I/O */
4648                                 memset(bh->b_data, 0, bh->b_size);
4649                                 set_buffer_uptodate(bh);
4650                                 unlock_buffer(bh);
4651                                 goto has_buffer;
4652                         }
4653                 }
4654
4655 make_io:
4656                 /*
4657                  * If we need to do any I/O, try to pre-readahead extra
4658                  * blocks from the inode table.
4659                  */
4660                 if (EXT4_SB(sb)->s_inode_readahead_blks) {
4661                         ext4_fsblk_t b, end, table;
4662                         unsigned num;
4663
4664                         table = ext4_inode_table(sb, gdp);
4665                         /* s_inode_readahead_blks is always a power of 2 */
4666                         b = block & ~(EXT4_SB(sb)->s_inode_readahead_blks-1);
4667                         if (table > b)
4668                                 b = table;
4669                         end = b + EXT4_SB(sb)->s_inode_readahead_blks;
4670                         num = EXT4_INODES_PER_GROUP(sb);
4671                         if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
4672                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
4673                                 num -= ext4_itable_unused_count(sb, gdp);
4674                         table += num / inodes_per_block;
4675                         if (end > table)
4676                                 end = table;
4677                         while (b <= end)
4678                                 sb_breadahead(sb, b++);
4679                 }
4680
4681                 /*
4682                  * There are other valid inodes in the buffer, this inode
4683                  * has in-inode xattrs, or we don't have this inode in memory.
4684                  * Read the block from disk.
4685                  */
4686                 get_bh(bh);
4687                 bh->b_end_io = end_buffer_read_sync;
4688                 submit_bh(READ_META, bh);
4689                 wait_on_buffer(bh);
4690                 if (!buffer_uptodate(bh)) {
4691                         ext4_error(sb, __func__,
4692                                    "unable to read inode block - inode=%lu, "
4693                                    "block=%llu", inode->i_ino, block);
4694                         brelse(bh);
4695                         return -EIO;
4696                 }
4697         }
4698 has_buffer:
4699         iloc->bh = bh;
4700         return 0;
4701 }
4702
4703 int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
4704 {
4705         /* We have all inode data except xattrs in memory here. */
4706         return __ext4_get_inode_loc(inode, iloc,
4707                 !(EXT4_I(inode)->i_state & EXT4_STATE_XATTR));
4708 }
4709
4710 void ext4_set_inode_flags(struct inode *inode)
4711 {
4712         unsigned int flags = EXT4_I(inode)->i_flags;
4713
4714         inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
4715         if (flags & EXT4_SYNC_FL)
4716                 inode->i_flags |= S_SYNC;
4717         if (flags & EXT4_APPEND_FL)
4718                 inode->i_flags |= S_APPEND;
4719         if (flags & EXT4_IMMUTABLE_FL)
4720                 inode->i_flags |= S_IMMUTABLE;
4721         if (flags & EXT4_NOATIME_FL)
4722                 inode->i_flags |= S_NOATIME;
4723         if (flags & EXT4_DIRSYNC_FL)
4724                 inode->i_flags |= S_DIRSYNC;
4725 }
4726
4727 /* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
4728 void ext4_get_inode_flags(struct ext4_inode_info *ei)
4729 {
4730         unsigned int flags = ei->vfs_inode.i_flags;
4731
4732         ei->i_flags &= ~(EXT4_SYNC_FL|EXT4_APPEND_FL|
4733                         EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|EXT4_DIRSYNC_FL);
4734         if (flags & S_SYNC)
4735                 ei->i_flags |= EXT4_SYNC_FL;
4736         if (flags & S_APPEND)
4737                 ei->i_flags |= EXT4_APPEND_FL;
4738         if (flags & S_IMMUTABLE)
4739                 ei->i_flags |= EXT4_IMMUTABLE_FL;
4740         if (flags & S_NOATIME)
4741                 ei->i_flags |= EXT4_NOATIME_FL;
4742         if (flags & S_DIRSYNC)
4743                 ei->i_flags |= EXT4_DIRSYNC_FL;
4744 }
4745
4746 static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
4747                                   struct ext4_inode_info *ei)
4748 {
4749         blkcnt_t i_blocks ;
4750         struct inode *inode = &(ei->vfs_inode);
4751         struct super_block *sb = inode->i_sb;
4752
4753         if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
4754                                 EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
4755                 /* we are using combined 48 bit field */
4756                 i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
4757                                         le32_to_cpu(raw_inode->i_blocks_lo);
4758                 if (ei->i_flags & EXT4_HUGE_FILE_FL) {
4759                         /* i_blocks represent file system block size */
4760                         return i_blocks  << (inode->i_blkbits - 9);
4761                 } else {
4762                         return i_blocks;
4763                 }
4764         } else {
4765                 return le32_to_cpu(raw_inode->i_blocks_lo);
4766         }
4767 }
4768
4769 struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
4770 {
4771         struct ext4_iloc iloc;
4772         struct ext4_inode *raw_inode;
4773         struct ext4_inode_info *ei;
4774         struct buffer_head *bh;
4775         struct inode *inode;
4776         long ret;
4777         int block;
4778
4779         inode = iget_locked(sb, ino);
4780         if (!inode)
4781                 return ERR_PTR(-ENOMEM);
4782         if (!(inode->i_state & I_NEW))
4783                 return inode;
4784
4785         ei = EXT4_I(inode);
4786
4787         ret = __ext4_get_inode_loc(inode, &iloc, 0);
4788         if (ret < 0)
4789                 goto bad_inode;
4790         bh = iloc.bh;
4791         raw_inode = ext4_raw_inode(&iloc);
4792         inode->i_mode = le16_to_cpu(raw_inode->i_mode);
4793         inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
4794         inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
4795         if (!(test_opt(inode->i_sb, NO_UID32))) {
4796                 inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
4797                 inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
4798         }
4799         inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
4800
4801         ei->i_state = 0;
4802         ei->i_dir_start_lookup = 0;
4803         ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
4804         /* We now have enough fields to check if the inode was active or not.
4805          * This is needed because nfsd might try to access dead inodes
4806          * the test is that same one that e2fsck uses
4807          * NeilBrown 1999oct15
4808          */
4809         if (inode->i_nlink == 0) {
4810                 if (inode->i_mode == 0 ||
4811                     !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
4812                         /* this inode is deleted */
4813                         brelse(bh);
4814                         ret = -ESTALE;
4815                         goto bad_inode;
4816                 }
4817                 /* The only unlinked inodes we let through here have
4818                  * valid i_mode and are being read by the orphan
4819                  * recovery code: that's fine, we're about to complete
4820                  * the process of deleting those. */
4821         }
4822         ei->i_flags = le32_to_cpu(raw_inode->i_flags);
4823         inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
4824         ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
4825         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_64BIT))
4826                 ei->i_file_acl |=
4827                         ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
4828         inode->i_size = ext4_isize(raw_inode);
4829         ei->i_disksize = inode->i_size;
4830         inode->i_generation = le32_to_cpu(raw_inode->i_generation);
4831         ei->i_block_group = iloc.block_group;
4832         ei->i_last_alloc_group = ~0;
4833         /*
4834          * NOTE! The in-memory inode i_data array is in little-endian order
4835          * even on big-endian machines: we do NOT byteswap the block numbers!
4836          */
4837         for (block = 0; block < EXT4_N_BLOCKS; block++)
4838                 ei->i_data[block] = raw_inode->i_block[block];
4839         INIT_LIST_HEAD(&ei->i_orphan);
4840
4841         if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4842                 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
4843                 if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
4844                     EXT4_INODE_SIZE(inode->i_sb)) {
4845                         brelse(bh);
4846                         ret = -EIO;
4847                         goto bad_inode;
4848                 }
4849                 if (ei->i_extra_isize == 0) {
4850                         /* The extra space is currently unused. Use it. */
4851                         ei->i_extra_isize = sizeof(struct ext4_inode) -
4852                                             EXT4_GOOD_OLD_INODE_SIZE;
4853                 } else {
4854                         __le32 *magic = (void *)raw_inode +
4855                                         EXT4_GOOD_OLD_INODE_SIZE +
4856                                         ei->i_extra_isize;
4857                         if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
4858                                 ei->i_state |= EXT4_STATE_XATTR;
4859                 }
4860         } else
4861                 ei->i_extra_isize = 0;
4862
4863         EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
4864         EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
4865         EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
4866         EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
4867
4868         inode->i_version = le32_to_cpu(raw_inode->i_disk_version);
4869         if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
4870                 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4871                         inode->i_version |=
4872                         (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
4873         }
4874
4875         ret = 0;
4876         if (ei->i_file_acl &&
4877             ((ei->i_file_acl <
4878               (le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block) +
4879                EXT4_SB(sb)->s_gdb_count)) ||
4880              (ei->i_file_acl >= ext4_blocks_count(EXT4_SB(sb)->s_es)))) {
4881                 ext4_error(sb, __func__,
4882                            "bad extended attribute block %llu in inode #%lu",
4883                            ei->i_file_acl, inode->i_ino);
4884                 ret = -EIO;
4885                 goto bad_inode;
4886         } else if (ei->i_flags & EXT4_EXTENTS_FL) {
4887                 if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4888                     (S_ISLNK(inode->i_mode) &&
4889                      !ext4_inode_is_fast_symlink(inode)))
4890                         /* Validate extent which is part of inode */
4891                         ret = ext4_ext_check_inode(inode);
4892         } else if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
4893                    (S_ISLNK(inode->i_mode) &&
4894                     !ext4_inode_is_fast_symlink(inode))) {
4895                 /* Validate block references which are part of inode */
4896                 ret = ext4_check_inode_blockref(inode);
4897         }
4898         if (ret) {
4899                 brelse(bh);
4900                 goto bad_inode;
4901         }
4902
4903         if (S_ISREG(inode->i_mode)) {
4904                 inode->i_op = &ext4_file_inode_operations;
4905                 inode->i_fop = &ext4_file_operations;
4906                 ext4_set_aops(inode);
4907         } else if (S_ISDIR(inode->i_mode)) {
4908                 inode->i_op = &ext4_dir_inode_operations;
4909                 inode->i_fop = &ext4_dir_operations;
4910         } else if (S_ISLNK(inode->i_mode)) {
4911                 if (ext4_inode_is_fast_symlink(inode)) {
4912                         inode->i_op = &ext4_fast_symlink_inode_operations;
4913                         nd_terminate_link(ei->i_data, inode->i_size,
4914                                 sizeof(ei->i_data) - 1);
4915                 } else {
4916                         inode->i_op = &ext4_symlink_inode_operations;
4917                         ext4_set_aops(inode);
4918                 }
4919         } else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
4920               S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
4921                 inode->i_op = &ext4_special_inode_operations;
4922                 if (raw_inode->i_block[0])
4923                         init_special_inode(inode, inode->i_mode,
4924                            old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
4925                 else
4926                         init_special_inode(inode, inode->i_mode,
4927                            new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
4928         } else {
4929                 brelse(bh);
4930                 ret = -EIO;
4931                 ext4_error(inode->i_sb, __func__,
4932                            "bogus i_mode (%o) for inode=%lu",
4933                            inode->i_mode, inode->i_ino);
4934                 goto bad_inode;
4935         }
4936         brelse(iloc.bh);
4937         ext4_set_inode_flags(inode);
4938         unlock_new_inode(inode);
4939         return inode;
4940
4941 bad_inode:
4942         iget_failed(inode);
4943         return ERR_PTR(ret);
4944 }
4945
4946 static int ext4_inode_blocks_set(handle_t *handle,
4947                                 struct ext4_inode *raw_inode,
4948                                 struct ext4_inode_info *ei)
4949 {
4950         struct inode *inode = &(ei->vfs_inode);
4951         u64 i_blocks = inode->i_blocks;
4952         struct super_block *sb = inode->i_sb;
4953
4954         if (i_blocks <= ~0U) {
4955                 /*
4956                  * i_blocks can be represnted in a 32 bit variable
4957                  * as multiple of 512 bytes
4958                  */
4959                 raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4960                 raw_inode->i_blocks_high = 0;
4961                 ei->i_flags &= ~EXT4_HUGE_FILE_FL;
4962                 return 0;
4963         }
4964         if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE))
4965                 return -EFBIG;
4966
4967         if (i_blocks <= 0xffffffffffffULL) {
4968                 /*
4969                  * i_blocks can be represented in a 48 bit variable
4970                  * as multiple of 512 bytes
4971                  */
4972                 raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4973                 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4974                 ei->i_flags &= ~EXT4_HUGE_FILE_FL;
4975         } else {
4976                 ei->i_flags |= EXT4_HUGE_FILE_FL;
4977                 /* i_block is stored in file system block size */
4978                 i_blocks = i_blocks >> (inode->i_blkbits - 9);
4979                 raw_inode->i_blocks_lo   = cpu_to_le32(i_blocks);
4980                 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
4981         }
4982         return 0;
4983 }
4984
4985 /*
4986  * Post the struct inode info into an on-disk inode location in the
4987  * buffer-cache.  This gobbles the caller's reference to the
4988  * buffer_head in the inode location struct.
4989  *
4990  * The caller must have write access to iloc->bh.
4991  */
4992 static int ext4_do_update_inode(handle_t *handle,
4993                                 struct inode *inode,
4994                                 struct ext4_iloc *iloc,
4995                                 int do_sync)
4996 {
4997         struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
4998         struct ext4_inode_info *ei = EXT4_I(inode);
4999         struct buffer_head *bh = iloc->bh;
5000         int err = 0, rc, block;
5001
5002         /* For fields not not tracking in the in-memory inode,
5003          * initialise them to zero for new inodes. */
5004         if (ei->i_state & EXT4_STATE_NEW)
5005                 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
5006
5007         ext4_get_inode_flags(ei);
5008         raw_inode->i_mode = cpu_to_le16(inode->i_mode);
5009         if (!(test_opt(inode->i_sb, NO_UID32))) {
5010                 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
5011                 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid));
5012 /*
5013  * Fix up interoperability with old kernels. Otherwise, old inodes get
5014  * re-used with the upper 16 bits of the uid/gid intact
5015  */
5016                 if (!ei->i_dtime) {
5017                         raw_inode->i_uid_high =
5018                                 cpu_to_le16(high_16_bits(inode->i_uid));
5019                         raw_inode->i_gid_high =
5020                                 cpu_to_le16(high_16_bits(inode->i_gid));
5021                 } else {
5022                         raw_inode->i_uid_high = 0;
5023                         raw_inode->i_gid_high = 0;
5024                 }
5025         } else {
5026                 raw_inode->i_uid_low =
5027                         cpu_to_le16(fs_high2lowuid(inode->i_uid));
5028                 raw_inode->i_gid_low =
5029                         cpu_to_le16(fs_high2lowgid(inode->i_gid));
5030                 raw_inode->i_uid_high = 0;
5031                 raw_inode->i_gid_high = 0;
5032         }
5033         raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
5034
5035         EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
5036         EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
5037         EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
5038         EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
5039
5040         if (ext4_inode_blocks_set(handle, raw_inode, ei))
5041                 goto out_brelse;
5042         raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
5043         raw_inode->i_flags = cpu_to_le32(ei->i_flags);
5044         if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
5045             cpu_to_le32(EXT4_OS_HURD))
5046                 raw_inode->i_file_acl_high =
5047                         cpu_to_le16(ei->i_file_acl >> 32);
5048         raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
5049         ext4_isize_set(raw_inode, ei->i_disksize);
5050         if (ei->i_disksize > 0x7fffffffULL) {
5051                 struct super_block *sb = inode->i_sb;
5052                 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
5053                                 EXT4_FEATURE_RO_COMPAT_LARGE_FILE) ||
5054                                 EXT4_SB(sb)->s_es->s_rev_level ==
5055                                 cpu_to_le32(EXT4_GOOD_OLD_REV)) {
5056                         /* If this is the first large file
5057                          * created, add a flag to the superblock.
5058                          */
5059                         err = ext4_journal_get_write_access(handle,
5060                                         EXT4_SB(sb)->s_sbh);
5061                         if (err)
5062                                 goto out_brelse;
5063                         ext4_update_dynamic_rev(sb);
5064                         EXT4_SET_RO_COMPAT_FEATURE(sb,
5065                                         EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
5066                         sb->s_dirt = 1;
5067                         ext4_handle_sync(handle);
5068                         err = ext4_handle_dirty_metadata(handle, inode,
5069                                         EXT4_SB(sb)->s_sbh);
5070                 }
5071         }
5072         raw_inode->i_generation = cpu_to_le32(inode->i_generation);
5073         if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
5074                 if (old_valid_dev(inode->i_rdev)) {
5075                         raw_inode->i_block[0] =
5076                                 cpu_to_le32(old_encode_dev(inode->i_rdev));
5077                         raw_inode->i_block[1] = 0;
5078                 } else {
5079                         raw_inode->i_block[0] = 0;
5080                         raw_inode->i_block[1] =
5081                                 cpu_to_le32(new_encode_dev(inode->i_rdev));
5082                         raw_inode->i_block[2] = 0;
5083                 }
5084         } else
5085                 for (block = 0; block < EXT4_N_BLOCKS; block++)
5086                         raw_inode->i_block[block] = ei->i_data[block];
5087
5088         raw_inode->i_disk_version = cpu_to_le32(inode->i_version);
5089         if (ei->i_extra_isize) {
5090                 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
5091                         raw_inode->i_version_hi =
5092                         cpu_to_le32(inode->i_version >> 32);
5093                 raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
5094         }
5095
5096         /*
5097          * If we're not using a journal and we were called from
5098          * ext4_write_inode() to sync the inode (making do_sync true),
5099          * we can just use sync_dirty_buffer() directly to do our dirty
5100          * work.  Testing s_journal here is a bit redundant but it's
5101          * worth it to avoid potential future trouble.
5102          */
5103         if (EXT4_SB(inode->i_sb)->s_journal == NULL && do_sync) {
5104                 BUFFER_TRACE(bh, "call sync_dirty_buffer");
5105                 sync_dirty_buffer(bh);
5106         } else {
5107                 BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
5108                 rc = ext4_handle_dirty_metadata(handle, inode, bh);
5109                 if (!err)
5110                         err = rc;
5111         }
5112         ei->i_state &= ~EXT4_STATE_NEW;
5113
5114 out_brelse:
5115         brelse(bh);
5116         ext4_std_error(inode->i_sb, err);
5117         return err;
5118 }
5119
5120 /*
5121  * ext4_write_inode()
5122  *
5123  * We are called from a few places:
5124  *
5125  * - Within generic_file_write() for O_SYNC files.
5126  *   Here, there will be no transaction running. We wait for any running
5127  *   trasnaction to commit.
5128  *
5129  * - Within sys_sync(), kupdate and such.
5130  *   We wait on commit, if tol to.
5131  *
5132  * - Within prune_icache() (PF_MEMALLOC == true)
5133  *   Here we simply return.  We can't afford to block kswapd on the
5134  *   journal commit.
5135  *
5136  * In all cases it is actually safe for us to return without doing anything,
5137  * because the inode has been copied into a raw inode buffer in
5138  * ext4_mark_inode_dirty().  This is a correctness thing for O_SYNC and for
5139  * knfsd.
5140  *
5141  * Note that we are absolutely dependent upon all inode dirtiers doing the
5142  * right thing: they *must* call mark_inode_dirty() after dirtying info in
5143  * which we are interested.
5144  *
5145  * It would be a bug for them to not do this.  The code:
5146  *
5147  *      mark_inode_dirty(inode)
5148  *      stuff();
5149  *      inode->i_size = expr;
5150  *
5151  * is in error because a kswapd-driven write_inode() could occur while
5152  * `stuff()' is running, and the new i_size will be lost.  Plus the inode
5153  * will no longer be on the superblock's dirty inode list.
5154  */
5155 int ext4_write_inode(struct inode *inode, int wait)
5156 {
5157         int err;
5158
5159         if (current->flags & PF_MEMALLOC)
5160                 return 0;
5161
5162         if (EXT4_SB(inode->i_sb)->s_journal) {
5163                 if (ext4_journal_current_handle()) {
5164                         jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
5165                         dump_stack();
5166                         return -EIO;
5167                 }
5168
5169                 if (!wait)
5170                         return 0;
5171
5172                 err = ext4_force_commit(inode->i_sb);
5173         } else {
5174                 struct ext4_iloc iloc;
5175
5176                 err = ext4_get_inode_loc(inode, &iloc);
5177                 if (err)
5178                         return err;
5179                 err = ext4_do_update_inode(EXT4_NOJOURNAL_HANDLE,
5180                                            inode, &iloc, wait);
5181         }
5182         return err;
5183 }
5184
5185 /*
5186  * ext4_setattr()
5187  *
5188  * Called from notify_change.
5189  *
5190  * We want to trap VFS attempts to truncate the file as soon as
5191  * possible.  In particular, we want to make sure that when the VFS
5192  * shrinks i_size, we put the inode on the orphan list and modify
5193  * i_disksize immediately, so that during the subsequent flushing of
5194  * dirty pages and freeing of disk blocks, we can guarantee that any
5195  * commit will leave the blocks being flushed in an unused state on
5196  * disk.  (On recovery, the inode will get truncated and the blocks will
5197  * be freed, so we have a strong guarantee that no future commit will
5198  * leave these blocks visible to the user.)
5199  *
5200  * Another thing we have to assure is that if we are in ordered mode
5201  * and inode is still attached to the committing transaction, we must
5202  * we start writeout of all the dirty pages which are being truncated.
5203  * This way we are sure that all the data written in the previous
5204  * transaction are already on disk (truncate waits for pages under
5205  * writeback).
5206  *
5207  * Called with inode->i_mutex down.
5208  */
5209 int ext4_setattr(struct dentry *dentry, struct iattr *attr)
5210 {
5211         struct inode *inode = dentry->d_inode;
5212         int error, rc = 0;
5213         const unsigned int ia_valid = attr->ia_valid;
5214
5215         error = inode_change_ok(inode, attr);
5216         if (error)
5217                 return error;
5218
5219         if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
5220                 (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) {
5221                 handle_t *handle;
5222
5223                 /* (user+group)*(old+new) structure, inode write (sb,
5224                  * inode block, ? - but truncate inode update has it) */
5225                 handle = ext4_journal_start(inode, 2*(EXT4_QUOTA_INIT_BLOCKS(inode->i_sb)+
5226                                         EXT4_QUOTA_DEL_BLOCKS(inode->i_sb))+3);
5227                 if (IS_ERR(handle)) {
5228                         error = PTR_ERR(handle);
5229                         goto err_out;
5230                 }
5231                 error = vfs_dq_transfer(inode, attr) ? -EDQUOT : 0;
5232                 if (error) {
5233                         ext4_journal_stop(handle);
5234                         return error;
5235                 }
5236                 /* Update corresponding info in inode so that everything is in
5237                  * one transaction */
5238                 if (attr->ia_valid & ATTR_UID)
5239                         inode->i_uid = attr->ia_uid;
5240                 if (attr->ia_valid & ATTR_GID)
5241                         inode->i_gid = attr->ia_gid;
5242                 error = ext4_mark_inode_dirty(handle, inode);
5243                 ext4_journal_stop(handle);
5244         }
5245
5246         if (attr->ia_valid & ATTR_SIZE) {
5247                 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) {
5248                         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5249
5250                         if (attr->ia_size > sbi->s_bitmap_maxbytes) {
5251                                 error = -EFBIG;
5252                                 goto err_out;
5253                         }
5254                 }
5255         }
5256
5257         if (S_ISREG(inode->i_mode) &&
5258             attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
5259                 handle_t *handle;
5260
5261                 handle = ext4_journal_start(inode, 3);
5262                 if (IS_ERR(handle)) {
5263                         error = PTR_ERR(handle);
5264                         goto err_out;
5265                 }
5266
5267                 error = ext4_orphan_add(handle, inode);
5268                 EXT4_I(inode)->i_disksize = attr->ia_size;
5269                 rc = ext4_mark_inode_dirty(handle, inode);
5270                 if (!error)
5271                         error = rc;
5272                 ext4_journal_stop(handle);
5273
5274                 if (ext4_should_order_data(inode)) {
5275                         error = ext4_begin_ordered_truncate(inode,
5276                                                             attr->ia_size);
5277                         if (error) {
5278                                 /* Do as much error cleanup as possible */
5279                                 handle = ext4_journal_start(inode, 3);
5280                                 if (IS_ERR(handle)) {
5281                                         ext4_orphan_del(NULL, inode);
5282                                         goto err_out;
5283                                 }
5284                                 ext4_orphan_del(handle, inode);
5285                                 ext4_journal_stop(handle);
5286                                 goto err_out;
5287                         }
5288                 }
5289         }
5290
5291         rc = inode_setattr(inode, attr);
5292
5293         /* If inode_setattr's call to ext4_truncate failed to get a
5294          * transaction handle at all, we need to clean up the in-core
5295          * orphan list manually. */
5296         if (inode->i_nlink)
5297                 ext4_orphan_del(NULL, inode);
5298
5299         if (!rc && (ia_valid & ATTR_MODE))
5300                 rc = ext4_acl_chmod(inode);
5301
5302 err_out:
5303         ext4_std_error(inode->i_sb, error);
5304         if (!error)
5305                 error = rc;
5306         return error;
5307 }
5308
5309 int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
5310                  struct kstat *stat)
5311 {
5312         struct inode *inode;
5313         unsigned long delalloc_blocks;
5314
5315         inode = dentry->d_inode;
5316         generic_fillattr(inode, stat);
5317
5318         /*
5319          * We can't update i_blocks if the block allocation is delayed
5320          * otherwise in the case of system crash before the real block
5321          * allocation is done, we will have i_blocks inconsistent with
5322          * on-disk file blocks.
5323          * We always keep i_blocks updated together with real
5324          * allocation. But to not confuse with user, stat
5325          * will return the blocks that include the delayed allocation
5326          * blocks for this file.
5327          */
5328         spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
5329         delalloc_blocks = EXT4_I(inode)->i_reserved_data_blocks;
5330         spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
5331
5332         stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9;
5333         return 0;
5334 }
5335
5336 static int ext4_indirect_trans_blocks(struct inode *inode, int nrblocks,
5337                                       int chunk)
5338 {
5339         int indirects;
5340
5341         /* if nrblocks are contiguous */
5342         if (chunk) {
5343                 /*
5344                  * With N contiguous data blocks, it need at most
5345                  * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) indirect blocks
5346                  * 2 dindirect blocks
5347                  * 1 tindirect block
5348                  */
5349                 indirects = nrblocks / EXT4_ADDR_PER_BLOCK(inode->i_sb);
5350                 return indirects + 3;
5351         }
5352         /*
5353          * if nrblocks are not contiguous, worse case, each block touch
5354          * a indirect block, and each indirect block touch a double indirect
5355          * block, plus a triple indirect block
5356          */
5357         indirects = nrblocks * 2 + 1;
5358         return indirects;
5359 }
5360
5361 static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
5362 {
5363         if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
5364                 return ext4_indirect_trans_blocks(inode, nrblocks, chunk);
5365         return ext4_ext_index_trans_blocks(inode, nrblocks, chunk);
5366 }
5367
5368 /*
5369  * Account for index blocks, block groups bitmaps and block group
5370  * descriptor blocks if modify datablocks and index blocks
5371  * worse case, the indexs blocks spread over different block groups
5372  *
5373  * If datablocks are discontiguous, they are possible to spread over
5374  * different block groups too. If they are contiugous, with flexbg,
5375  * they could still across block group boundary.
5376  *
5377  * Also account for superblock, inode, quota and xattr blocks
5378  */
5379 int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
5380 {
5381         ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);
5382         int gdpblocks;
5383         int idxblocks;
5384         int ret = 0;
5385
5386         /*
5387          * How many index blocks need to touch to modify nrblocks?
5388          * The "Chunk" flag indicating whether the nrblocks is
5389          * physically contiguous on disk
5390          *
5391          * For Direct IO and fallocate, they calls get_block to allocate
5392          * one single extent at a time, so they could set the "Chunk" flag
5393          */
5394         idxblocks = ext4_index_trans_blocks(inode, nrblocks, chunk);
5395
5396         ret = idxblocks;
5397
5398         /*
5399          * Now let's see how many group bitmaps and group descriptors need
5400          * to account
5401          */
5402         groups = idxblocks;
5403         if (chunk)
5404                 groups += 1;
5405         else
5406                 groups += nrblocks;
5407
5408         gdpblocks = groups;
5409         if (groups > ngroups)
5410                 groups = ngroups;
5411         if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
5412                 gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
5413
5414         /* bitmaps and block group descriptor blocks */
5415         ret += groups + gdpblocks;
5416
5417         /* Blocks for super block, inode, quota and xattr blocks */
5418         ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
5419
5420         return ret;
5421 }
5422
5423 /*
5424  * Calulate the total number of credits to reserve to fit
5425  * the modification of a single pages into a single transaction,
5426  * which may include multiple chunks of block allocations.
5427  *
5428  * This could be called via ext4_write_begin()
5429  *
5430  * We need to consider the worse case, when
5431  * one new block per extent.
5432  */
5433 int ext4_writepage_trans_blocks(struct inode *inode)
5434 {
5435         int bpp = ext4_journal_blocks_per_page(inode);
5436         int ret;
5437
5438         ret = ext4_meta_trans_blocks(inode, bpp, 0);
5439
5440         /* Account for data blocks for journalled mode */
5441         if (ext4_should_journal_data(inode))
5442                 ret += bpp;
5443         return ret;
5444 }
5445
5446 /*
5447  * Calculate the journal credits for a chunk of data modification.
5448  *
5449  * This is called from DIO, fallocate or whoever calling
5450  * ext4_get_blocks() to map/allocate a chunk of contigous disk blocks.
5451  *
5452  * journal buffers for data blocks are not included here, as DIO
5453  * and fallocate do no need to journal data buffers.
5454  */
5455 int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
5456 {
5457         return ext4_meta_trans_blocks(inode, nrblocks, 1);
5458 }
5459
5460 /*
5461  * The caller must have previously called ext4_reserve_inode_write().
5462  * Give this, we know that the caller already has write access to iloc->bh.
5463  */
5464 int ext4_mark_iloc_dirty(handle_t *handle,
5465                          struct inode *inode, struct ext4_iloc *iloc)
5466 {
5467         int err = 0;
5468
5469         if (test_opt(inode->i_sb, I_VERSION))
5470                 inode_inc_iversion(inode);
5471
5472         /* the do_update_inode consumes one bh->b_count */
5473         get_bh(iloc->bh);
5474
5475         /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
5476         err = ext4_do_update_inode(handle, inode, iloc, 0);
5477         put_bh(iloc->bh);
5478         return err;
5479 }
5480
5481 /*
5482  * On success, We end up with an outstanding reference count against
5483  * iloc->bh.  This _must_ be cleaned up later.
5484  */
5485
5486 int
5487 ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
5488                          struct ext4_iloc *iloc)
5489 {
5490         int err;
5491
5492         err = ext4_get_inode_loc(inode, iloc);
5493         if (!err) {
5494                 BUFFER_TRACE(iloc->bh, "get_write_access");
5495                 err = ext4_journal_get_write_access(handle, iloc->bh);
5496                 if (err) {
5497                         brelse(iloc->bh);
5498                         iloc->bh = NULL;
5499                 }
5500         }
5501         ext4_std_error(inode->i_sb, err);
5502         return err;
5503 }
5504
5505 /*
5506  * Expand an inode by new_extra_isize bytes.
5507  * Returns 0 on success or negative error number on failure.
5508  */
5509 static int ext4_expand_extra_isize(struct inode *inode,
5510                                    unsigned int new_extra_isize,
5511                                    struct ext4_iloc iloc,
5512                                    handle_t *handle)
5513 {
5514         struct ext4_inode *raw_inode;
5515         struct ext4_xattr_ibody_header *header;
5516         struct ext4_xattr_entry *entry;
5517
5518         if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
5519                 return 0;
5520
5521         raw_inode = ext4_raw_inode(&iloc);
5522
5523         header = IHDR(inode, raw_inode);
5524         entry = IFIRST(header);
5525
5526         /* No extended attributes present */
5527         if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR) ||
5528                 header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
5529                 memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0,
5530                         new_extra_isize);
5531                 EXT4_I(inode)->i_extra_isize = new_extra_isize;
5532                 return 0;
5533         }
5534
5535         /* try to expand with EAs present */
5536         return ext4_expand_extra_isize_ea(inode, new_extra_isize,
5537                                           raw_inode, handle);
5538 }
5539
5540 /*
5541  * What we do here is to mark the in-core inode as clean with respect to inode
5542  * dirtiness (it may still be data-dirty).
5543  * This means that the in-core inode may be reaped by prune_icache
5544  * without having to perform any I/O.  This is a very good thing,
5545  * because *any* task may call prune_icache - even ones which
5546  * have a transaction open against a different journal.
5547  *
5548  * Is this cheating?  Not really.  Sure, we haven't written the
5549  * inode out, but prune_icache isn't a user-visible syncing function.
5550  * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
5551  * we start and wait on commits.
5552  *
5553  * Is this efficient/effective?  Well, we're being nice to the system
5554  * by cleaning up our inodes proactively so they can be reaped
5555  * without I/O.  But we are potentially leaving up to five seconds'
5556  * worth of inodes floating about which prune_icache wants us to
5557  * write out.  One way to fix that would be to get prune_icache()
5558  * to do a write_super() to free up some memory.  It has the desired
5559  * effect.
5560  */
5561 int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
5562 {
5563         struct ext4_iloc iloc;
5564         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
5565         static unsigned int mnt_count;
5566         int err, ret;
5567
5568         might_sleep();
5569         err = ext4_reserve_inode_write(handle, inode, &iloc);
5570         if (ext4_handle_valid(handle) &&
5571             EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
5572             !(EXT4_I(inode)->i_state & EXT4_STATE_NO_EXPAND)) {
5573                 /*
5574                  * We need extra buffer credits since we may write into EA block
5575                  * with this same handle. If journal_extend fails, then it will
5576                  * only result in a minor loss of functionality for that inode.
5577                  * If this is felt to be critical, then e2fsck should be run to
5578                  * force a large enough s_min_extra_isize.
5579                  */
5580                 if ((jbd2_journal_extend(handle,
5581                              EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) {
5582                         ret = ext4_expand_extra_isize(inode,
5583                                                       sbi->s_want_extra_isize,
5584                                                       iloc, handle);
5585                         if (ret) {
5586                                 EXT4_I(inode)->i_state |= EXT4_STATE_NO_EXPAND;
5587                                 if (mnt_count !=
5588                                         le16_to_cpu(sbi->s_es->s_mnt_count)) {
5589                                         ext4_warning(inode->i_sb, __func__,
5590                                         "Unable to expand inode %lu. Delete"
5591                                         " some EAs or run e2fsck.",
5592                                         inode->i_ino);
5593                                         mnt_count =
5594                                           le16_to_cpu(sbi->s_es->s_mnt_count);
5595                                 }
5596                         }
5597                 }
5598         }
5599         if (!err)
5600                 err = ext4_mark_iloc_dirty(handle, inode, &iloc);
5601         return err;
5602 }
5603
5604 /*
5605  * ext4_dirty_inode() is called from __mark_inode_dirty()
5606  *
5607  *&