fs: pass exact type of data dirties to ->dirty_inode
[linux-2.6.git] / fs / ext3 / inode.c
1 /*
2  *  linux/fs/ext3/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 ext3_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/ext3_jbd.h>
29 #include <linux/jbd.h>
30 #include <linux/highuid.h>
31 #include <linux/pagemap.h>
32 #include <linux/quotaops.h>
33 #include <linux/string.h>
34 #include <linux/buffer_head.h>
35 #include <linux/writeback.h>
36 #include <linux/mpage.h>
37 #include <linux/uio.h>
38 #include <linux/bio.h>
39 #include <linux/fiemap.h>
40 #include <linux/namei.h>
41 #include "xattr.h"
42 #include "acl.h"
43
44 static int ext3_writepage_trans_blocks(struct inode *inode);
45
46 /*
47  * Test whether an inode is a fast symlink.
48  */
49 static int ext3_inode_is_fast_symlink(struct inode *inode)
50 {
51         int ea_blocks = EXT3_I(inode)->i_file_acl ?
52                 (inode->i_sb->s_blocksize >> 9) : 0;
53
54         return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
55 }
56
57 /*
58  * The ext3 forget function must perform a revoke if we are freeing data
59  * which has been journaled.  Metadata (eg. indirect blocks) must be
60  * revoked in all cases.
61  *
62  * "bh" may be NULL: a metadata block may have been freed from memory
63  * but there may still be a record of it in the journal, and that record
64  * still needs to be revoked.
65  */
66 int ext3_forget(handle_t *handle, int is_metadata, struct inode *inode,
67                         struct buffer_head *bh, ext3_fsblk_t blocknr)
68 {
69         int err;
70
71         might_sleep();
72
73         BUFFER_TRACE(bh, "enter");
74
75         jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
76                   "data mode %lx\n",
77                   bh, is_metadata, inode->i_mode,
78                   test_opt(inode->i_sb, DATA_FLAGS));
79
80         /* Never use the revoke function if we are doing full data
81          * journaling: there is no need to, and a V1 superblock won't
82          * support it.  Otherwise, only skip the revoke on un-journaled
83          * data blocks. */
84
85         if (test_opt(inode->i_sb, DATA_FLAGS) == EXT3_MOUNT_JOURNAL_DATA ||
86             (!is_metadata && !ext3_should_journal_data(inode))) {
87                 if (bh) {
88                         BUFFER_TRACE(bh, "call journal_forget");
89                         return ext3_journal_forget(handle, bh);
90                 }
91                 return 0;
92         }
93
94         /*
95          * data!=journal && (is_metadata || should_journal_data(inode))
96          */
97         BUFFER_TRACE(bh, "call ext3_journal_revoke");
98         err = ext3_journal_revoke(handle, blocknr, bh);
99         if (err)
100                 ext3_abort(inode->i_sb, __func__,
101                            "error %d when attempting revoke", err);
102         BUFFER_TRACE(bh, "exit");
103         return err;
104 }
105
106 /*
107  * Work out how many blocks we need to proceed with the next chunk of a
108  * truncate transaction.
109  */
110 static unsigned long blocks_for_truncate(struct inode *inode)
111 {
112         unsigned long needed;
113
114         needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
115
116         /* Give ourselves just enough room to cope with inodes in which
117          * i_blocks is corrupt: we've seen disk corruptions in the past
118          * which resulted in random data in an inode which looked enough
119          * like a regular file for ext3 to try to delete it.  Things
120          * will go a bit crazy if that happens, but at least we should
121          * try not to panic the whole kernel. */
122         if (needed < 2)
123                 needed = 2;
124
125         /* But we need to bound the transaction so we don't overflow the
126          * journal. */
127         if (needed > EXT3_MAX_TRANS_DATA)
128                 needed = EXT3_MAX_TRANS_DATA;
129
130         return EXT3_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
131 }
132
133 /*
134  * Truncate transactions can be complex and absolutely huge.  So we need to
135  * be able to restart the transaction at a conventient checkpoint to make
136  * sure we don't overflow the journal.
137  *
138  * start_transaction gets us a new handle for a truncate transaction,
139  * and extend_transaction tries to extend the existing one a bit.  If
140  * extend fails, we need to propagate the failure up and restart the
141  * transaction in the top-level truncate loop. --sct
142  */
143 static handle_t *start_transaction(struct inode *inode)
144 {
145         handle_t *result;
146
147         result = ext3_journal_start(inode, blocks_for_truncate(inode));
148         if (!IS_ERR(result))
149                 return result;
150
151         ext3_std_error(inode->i_sb, PTR_ERR(result));
152         return result;
153 }
154
155 /*
156  * Try to extend this transaction for the purposes of truncation.
157  *
158  * Returns 0 if we managed to create more room.  If we can't create more
159  * room, and the transaction must be restarted we return 1.
160  */
161 static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
162 {
163         if (handle->h_buffer_credits > EXT3_RESERVE_TRANS_BLOCKS)
164                 return 0;
165         if (!ext3_journal_extend(handle, blocks_for_truncate(inode)))
166                 return 0;
167         return 1;
168 }
169
170 /*
171  * Restart the transaction associated with *handle.  This does a commit,
172  * so before we call here everything must be consistently dirtied against
173  * this transaction.
174  */
175 static int truncate_restart_transaction(handle_t *handle, struct inode *inode)
176 {
177         int ret;
178
179         jbd_debug(2, "restarting handle %p\n", handle);
180         /*
181          * Drop truncate_mutex to avoid deadlock with ext3_get_blocks_handle
182          * At this moment, get_block can be called only for blocks inside
183          * i_size since page cache has been already dropped and writes are
184          * blocked by i_mutex. So we can safely drop the truncate_mutex.
185          */
186         mutex_unlock(&EXT3_I(inode)->truncate_mutex);
187         ret = ext3_journal_restart(handle, blocks_for_truncate(inode));
188         mutex_lock(&EXT3_I(inode)->truncate_mutex);
189         return ret;
190 }
191
192 /*
193  * Called at inode eviction from icache
194  */
195 void ext3_evict_inode (struct inode *inode)
196 {
197         struct ext3_block_alloc_info *rsv;
198         handle_t *handle;
199         int want_delete = 0;
200
201         if (!inode->i_nlink && !is_bad_inode(inode)) {
202                 dquot_initialize(inode);
203                 want_delete = 1;
204         }
205
206         truncate_inode_pages(&inode->i_data, 0);
207
208         ext3_discard_reservation(inode);
209         rsv = EXT3_I(inode)->i_block_alloc_info;
210         EXT3_I(inode)->i_block_alloc_info = NULL;
211         if (unlikely(rsv))
212                 kfree(rsv);
213
214         if (!want_delete)
215                 goto no_delete;
216
217         handle = start_transaction(inode);
218         if (IS_ERR(handle)) {
219                 /*
220                  * If we're going to skip the normal cleanup, we still need to
221                  * make sure that the in-core orphan linked list is properly
222                  * cleaned up.
223                  */
224                 ext3_orphan_del(NULL, inode);
225                 goto no_delete;
226         }
227
228         if (IS_SYNC(inode))
229                 handle->h_sync = 1;
230         inode->i_size = 0;
231         if (inode->i_blocks)
232                 ext3_truncate(inode);
233         /*
234          * Kill off the orphan record which ext3_truncate created.
235          * AKPM: I think this can be inside the above `if'.
236          * Note that ext3_orphan_del() has to be able to cope with the
237          * deletion of a non-existent orphan - this is because we don't
238          * know if ext3_truncate() actually created an orphan record.
239          * (Well, we could do this if we need to, but heck - it works)
240          */
241         ext3_orphan_del(handle, inode);
242         EXT3_I(inode)->i_dtime  = get_seconds();
243
244         /*
245          * One subtle ordering requirement: if anything has gone wrong
246          * (transaction abort, IO errors, whatever), then we can still
247          * do these next steps (the fs will already have been marked as
248          * having errors), but we can't free the inode if the mark_dirty
249          * fails.
250          */
251         if (ext3_mark_inode_dirty(handle, inode)) {
252                 /* If that failed, just dquot_drop() and be done with that */
253                 dquot_drop(inode);
254                 end_writeback(inode);
255         } else {
256                 ext3_xattr_delete_inode(handle, inode);
257                 dquot_free_inode(inode);
258                 dquot_drop(inode);
259                 end_writeback(inode);
260                 ext3_free_inode(handle, inode);
261         }
262         ext3_journal_stop(handle);
263         return;
264 no_delete:
265         end_writeback(inode);
266         dquot_drop(inode);
267 }
268
269 typedef struct {
270         __le32  *p;
271         __le32  key;
272         struct buffer_head *bh;
273 } Indirect;
274
275 static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
276 {
277         p->key = *(p->p = v);
278         p->bh = bh;
279 }
280
281 static int verify_chain(Indirect *from, Indirect *to)
282 {
283         while (from <= to && from->key == *from->p)
284                 from++;
285         return (from > to);
286 }
287
288 /**
289  *      ext3_block_to_path - parse the block number into array of offsets
290  *      @inode: inode in question (we are only interested in its superblock)
291  *      @i_block: block number to be parsed
292  *      @offsets: array to store the offsets in
293  *      @boundary: set this non-zero if the referred-to block is likely to be
294  *             followed (on disk) by an indirect block.
295  *
296  *      To store the locations of file's data ext3 uses a data structure common
297  *      for UNIX filesystems - tree of pointers anchored in the inode, with
298  *      data blocks at leaves and indirect blocks in intermediate nodes.
299  *      This function translates the block number into path in that tree -
300  *      return value is the path length and @offsets[n] is the offset of
301  *      pointer to (n+1)th node in the nth one. If @block is out of range
302  *      (negative or too large) warning is printed and zero returned.
303  *
304  *      Note: function doesn't find node addresses, so no IO is needed. All
305  *      we need to know is the capacity of indirect blocks (taken from the
306  *      inode->i_sb).
307  */
308
309 /*
310  * Portability note: the last comparison (check that we fit into triple
311  * indirect block) is spelled differently, because otherwise on an
312  * architecture with 32-bit longs and 8Kb pages we might get into trouble
313  * if our filesystem had 8Kb blocks. We might use long long, but that would
314  * kill us on x86. Oh, well, at least the sign propagation does not matter -
315  * i_block would have to be negative in the very beginning, so we would not
316  * get there at all.
317  */
318
319 static int ext3_block_to_path(struct inode *inode,
320                         long i_block, int offsets[4], int *boundary)
321 {
322         int ptrs = EXT3_ADDR_PER_BLOCK(inode->i_sb);
323         int ptrs_bits = EXT3_ADDR_PER_BLOCK_BITS(inode->i_sb);
324         const long direct_blocks = EXT3_NDIR_BLOCKS,
325                 indirect_blocks = ptrs,
326                 double_blocks = (1 << (ptrs_bits * 2));
327         int n = 0;
328         int final = 0;
329
330         if (i_block < 0) {
331                 ext3_warning (inode->i_sb, "ext3_block_to_path", "block < 0");
332         } else if (i_block < direct_blocks) {
333                 offsets[n++] = i_block;
334                 final = direct_blocks;
335         } else if ( (i_block -= direct_blocks) < indirect_blocks) {
336                 offsets[n++] = EXT3_IND_BLOCK;
337                 offsets[n++] = i_block;
338                 final = ptrs;
339         } else if ((i_block -= indirect_blocks) < double_blocks) {
340                 offsets[n++] = EXT3_DIND_BLOCK;
341                 offsets[n++] = i_block >> ptrs_bits;
342                 offsets[n++] = i_block & (ptrs - 1);
343                 final = ptrs;
344         } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
345                 offsets[n++] = EXT3_TIND_BLOCK;
346                 offsets[n++] = i_block >> (ptrs_bits * 2);
347                 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
348                 offsets[n++] = i_block & (ptrs - 1);
349                 final = ptrs;
350         } else {
351                 ext3_warning(inode->i_sb, "ext3_block_to_path", "block > big");
352         }
353         if (boundary)
354                 *boundary = final - 1 - (i_block & (ptrs - 1));
355         return n;
356 }
357
358 /**
359  *      ext3_get_branch - read the chain of indirect blocks leading to data
360  *      @inode: inode in question
361  *      @depth: depth of the chain (1 - direct pointer, etc.)
362  *      @offsets: offsets of pointers in inode/indirect blocks
363  *      @chain: place to store the result
364  *      @err: here we store the error value
365  *
366  *      Function fills the array of triples <key, p, bh> and returns %NULL
367  *      if everything went OK or the pointer to the last filled triple
368  *      (incomplete one) otherwise. Upon the return chain[i].key contains
369  *      the number of (i+1)-th block in the chain (as it is stored in memory,
370  *      i.e. little-endian 32-bit), chain[i].p contains the address of that
371  *      number (it points into struct inode for i==0 and into the bh->b_data
372  *      for i>0) and chain[i].bh points to the buffer_head of i-th indirect
373  *      block for i>0 and NULL for i==0. In other words, it holds the block
374  *      numbers of the chain, addresses they were taken from (and where we can
375  *      verify that chain did not change) and buffer_heads hosting these
376  *      numbers.
377  *
378  *      Function stops when it stumbles upon zero pointer (absent block)
379  *              (pointer to last triple returned, *@err == 0)
380  *      or when it gets an IO error reading an indirect block
381  *              (ditto, *@err == -EIO)
382  *      or when it notices that chain had been changed while it was reading
383  *              (ditto, *@err == -EAGAIN)
384  *      or when it reads all @depth-1 indirect blocks successfully and finds
385  *      the whole chain, all way to the data (returns %NULL, *err == 0).
386  */
387 static Indirect *ext3_get_branch(struct inode *inode, int depth, int *offsets,
388                                  Indirect chain[4], int *err)
389 {
390         struct super_block *sb = inode->i_sb;
391         Indirect *p = chain;
392         struct buffer_head *bh;
393
394         *err = 0;
395         /* i_data is not going away, no lock needed */
396         add_chain (chain, NULL, EXT3_I(inode)->i_data + *offsets);
397         if (!p->key)
398                 goto no_block;
399         while (--depth) {
400                 bh = sb_bread(sb, le32_to_cpu(p->key));
401                 if (!bh)
402                         goto failure;
403                 /* Reader: pointers */
404                 if (!verify_chain(chain, p))
405                         goto changed;
406                 add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
407                 /* Reader: end */
408                 if (!p->key)
409                         goto no_block;
410         }
411         return NULL;
412
413 changed:
414         brelse(bh);
415         *err = -EAGAIN;
416         goto no_block;
417 failure:
418         *err = -EIO;
419 no_block:
420         return p;
421 }
422
423 /**
424  *      ext3_find_near - find a place for allocation with sufficient locality
425  *      @inode: owner
426  *      @ind: descriptor of indirect block.
427  *
428  *      This function returns the preferred place for block allocation.
429  *      It is used when heuristic for sequential allocation fails.
430  *      Rules are:
431  *        + if there is a block to the left of our position - allocate near it.
432  *        + if pointer will live in indirect block - allocate near that block.
433  *        + if pointer will live in inode - allocate in the same
434  *          cylinder group.
435  *
436  * In the latter case we colour the starting block by the callers PID to
437  * prevent it from clashing with concurrent allocations for a different inode
438  * in the same block group.   The PID is used here so that functionally related
439  * files will be close-by on-disk.
440  *
441  *      Caller must make sure that @ind is valid and will stay that way.
442  */
443 static ext3_fsblk_t ext3_find_near(struct inode *inode, Indirect *ind)
444 {
445         struct ext3_inode_info *ei = EXT3_I(inode);
446         __le32 *start = ind->bh ? (__le32*) ind->bh->b_data : ei->i_data;
447         __le32 *p;
448         ext3_fsblk_t bg_start;
449         ext3_grpblk_t colour;
450
451         /* Try to find previous block */
452         for (p = ind->p - 1; p >= start; p--) {
453                 if (*p)
454                         return le32_to_cpu(*p);
455         }
456
457         /* No such thing, so let's try location of indirect block */
458         if (ind->bh)
459                 return ind->bh->b_blocknr;
460
461         /*
462          * It is going to be referred to from the inode itself? OK, just put it
463          * into the same cylinder group then.
464          */
465         bg_start = ext3_group_first_block_no(inode->i_sb, ei->i_block_group);
466         colour = (current->pid % 16) *
467                         (EXT3_BLOCKS_PER_GROUP(inode->i_sb) / 16);
468         return bg_start + colour;
469 }
470
471 /**
472  *      ext3_find_goal - find a preferred place for allocation.
473  *      @inode: owner
474  *      @block:  block we want
475  *      @partial: pointer to the last triple within a chain
476  *
477  *      Normally this function find the preferred place for block allocation,
478  *      returns it.
479  */
480
481 static ext3_fsblk_t ext3_find_goal(struct inode *inode, long block,
482                                    Indirect *partial)
483 {
484         struct ext3_block_alloc_info *block_i;
485
486         block_i =  EXT3_I(inode)->i_block_alloc_info;
487
488         /*
489          * try the heuristic for sequential allocation,
490          * failing that at least try to get decent locality.
491          */
492         if (block_i && (block == block_i->last_alloc_logical_block + 1)
493                 && (block_i->last_alloc_physical_block != 0)) {
494                 return block_i->last_alloc_physical_block + 1;
495         }
496
497         return ext3_find_near(inode, partial);
498 }
499
500 /**
501  *      ext3_blks_to_allocate - Look up the block map and count the number
502  *      of direct blocks need to be allocated for the given branch.
503  *
504  *      @branch: chain of indirect blocks
505  *      @k: number of blocks need for indirect blocks
506  *      @blks: number of data blocks to be mapped.
507  *      @blocks_to_boundary:  the offset in the indirect block
508  *
509  *      return the total number of blocks to be allocate, including the
510  *      direct and indirect blocks.
511  */
512 static int ext3_blks_to_allocate(Indirect *branch, int k, unsigned long blks,
513                 int blocks_to_boundary)
514 {
515         unsigned long count = 0;
516
517         /*
518          * Simple case, [t,d]Indirect block(s) has not allocated yet
519          * then it's clear blocks on that path have not allocated
520          */
521         if (k > 0) {
522                 /* right now we don't handle cross boundary allocation */
523                 if (blks < blocks_to_boundary + 1)
524                         count += blks;
525                 else
526                         count += blocks_to_boundary + 1;
527                 return count;
528         }
529
530         count++;
531         while (count < blks && count <= blocks_to_boundary &&
532                 le32_to_cpu(*(branch[0].p + count)) == 0) {
533                 count++;
534         }
535         return count;
536 }
537
538 /**
539  *      ext3_alloc_blocks - multiple allocate blocks needed for a branch
540  *      @handle: handle for this transaction
541  *      @inode: owner
542  *      @goal: preferred place for allocation
543  *      @indirect_blks: the number of blocks need to allocate for indirect
544  *                      blocks
545  *      @blks:  number of blocks need to allocated for direct blocks
546  *      @new_blocks: on return it will store the new block numbers for
547  *      the indirect blocks(if needed) and the first direct block,
548  *      @err: here we store the error value
549  *
550  *      return the number of direct blocks allocated
551  */
552 static int ext3_alloc_blocks(handle_t *handle, struct inode *inode,
553                         ext3_fsblk_t goal, int indirect_blks, int blks,
554                         ext3_fsblk_t new_blocks[4], int *err)
555 {
556         int target, i;
557         unsigned long count = 0;
558         int index = 0;
559         ext3_fsblk_t current_block = 0;
560         int ret = 0;
561
562         /*
563          * Here we try to allocate the requested multiple blocks at once,
564          * on a best-effort basis.
565          * To build a branch, we should allocate blocks for
566          * the indirect blocks(if not allocated yet), and at least
567          * the first direct block of this branch.  That's the
568          * minimum number of blocks need to allocate(required)
569          */
570         target = blks + indirect_blks;
571
572         while (1) {
573                 count = target;
574                 /* allocating blocks for indirect blocks and direct blocks */
575                 current_block = ext3_new_blocks(handle,inode,goal,&count,err);
576                 if (*err)
577                         goto failed_out;
578
579                 target -= count;
580                 /* allocate blocks for indirect blocks */
581                 while (index < indirect_blks && count) {
582                         new_blocks[index++] = current_block++;
583                         count--;
584                 }
585
586                 if (count > 0)
587                         break;
588         }
589
590         /* save the new block number for the first direct block */
591         new_blocks[index] = current_block;
592
593         /* total number of blocks allocated for direct blocks */
594         ret = count;
595         *err = 0;
596         return ret;
597 failed_out:
598         for (i = 0; i <index; i++)
599                 ext3_free_blocks(handle, inode, new_blocks[i], 1);
600         return ret;
601 }
602
603 /**
604  *      ext3_alloc_branch - allocate and set up a chain of blocks.
605  *      @handle: handle for this transaction
606  *      @inode: owner
607  *      @indirect_blks: number of allocated indirect blocks
608  *      @blks: number of allocated direct blocks
609  *      @goal: preferred place for allocation
610  *      @offsets: offsets (in the blocks) to store the pointers to next.
611  *      @branch: place to store the chain in.
612  *
613  *      This function allocates blocks, zeroes out all but the last one,
614  *      links them into chain and (if we are synchronous) writes them to disk.
615  *      In other words, it prepares a branch that can be spliced onto the
616  *      inode. It stores the information about that chain in the branch[], in
617  *      the same format as ext3_get_branch() would do. We are calling it after
618  *      we had read the existing part of chain and partial points to the last
619  *      triple of that (one with zero ->key). Upon the exit we have the same
620  *      picture as after the successful ext3_get_block(), except that in one
621  *      place chain is disconnected - *branch->p is still zero (we did not
622  *      set the last link), but branch->key contains the number that should
623  *      be placed into *branch->p to fill that gap.
624  *
625  *      If allocation fails we free all blocks we've allocated (and forget
626  *      their buffer_heads) and return the error value the from failed
627  *      ext3_alloc_block() (normally -ENOSPC). Otherwise we set the chain
628  *      as described above and return 0.
629  */
630 static int ext3_alloc_branch(handle_t *handle, struct inode *inode,
631                         int indirect_blks, int *blks, ext3_fsblk_t goal,
632                         int *offsets, Indirect *branch)
633 {
634         int blocksize = inode->i_sb->s_blocksize;
635         int i, n = 0;
636         int err = 0;
637         struct buffer_head *bh;
638         int num;
639         ext3_fsblk_t new_blocks[4];
640         ext3_fsblk_t current_block;
641
642         num = ext3_alloc_blocks(handle, inode, goal, indirect_blks,
643                                 *blks, new_blocks, &err);
644         if (err)
645                 return err;
646
647         branch[0].key = cpu_to_le32(new_blocks[0]);
648         /*
649          * metadata blocks and data blocks are allocated.
650          */
651         for (n = 1; n <= indirect_blks;  n++) {
652                 /*
653                  * Get buffer_head for parent block, zero it out
654                  * and set the pointer to new one, then send
655                  * parent to disk.
656                  */
657                 bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
658                 branch[n].bh = bh;
659                 lock_buffer(bh);
660                 BUFFER_TRACE(bh, "call get_create_access");
661                 err = ext3_journal_get_create_access(handle, bh);
662                 if (err) {
663                         unlock_buffer(bh);
664                         brelse(bh);
665                         goto failed;
666                 }
667
668                 memset(bh->b_data, 0, blocksize);
669                 branch[n].p = (__le32 *) bh->b_data + offsets[n];
670                 branch[n].key = cpu_to_le32(new_blocks[n]);
671                 *branch[n].p = branch[n].key;
672                 if ( n == indirect_blks) {
673                         current_block = new_blocks[n];
674                         /*
675                          * End of chain, update the last new metablock of
676                          * the chain to point to the new allocated
677                          * data blocks numbers
678                          */
679                         for (i=1; i < num; i++)
680                                 *(branch[n].p + i) = cpu_to_le32(++current_block);
681                 }
682                 BUFFER_TRACE(bh, "marking uptodate");
683                 set_buffer_uptodate(bh);
684                 unlock_buffer(bh);
685
686                 BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
687                 err = ext3_journal_dirty_metadata(handle, bh);
688                 if (err)
689                         goto failed;
690         }
691         *blks = num;
692         return err;
693 failed:
694         /* Allocation failed, free what we already allocated */
695         for (i = 1; i <= n ; i++) {
696                 BUFFER_TRACE(branch[i].bh, "call journal_forget");
697                 ext3_journal_forget(handle, branch[i].bh);
698         }
699         for (i = 0; i <indirect_blks; i++)
700                 ext3_free_blocks(handle, inode, new_blocks[i], 1);
701
702         ext3_free_blocks(handle, inode, new_blocks[i], num);
703
704         return err;
705 }
706
707 /**
708  * ext3_splice_branch - splice the allocated branch onto inode.
709  * @handle: handle for this transaction
710  * @inode: owner
711  * @block: (logical) number of block we are adding
712  * @where: location of missing link
713  * @num:   number of indirect blocks we are adding
714  * @blks:  number of direct blocks we are adding
715  *
716  * This function fills the missing link and does all housekeeping needed in
717  * inode (->i_blocks, etc.). In case of success we end up with the full
718  * chain to new block and return 0.
719  */
720 static int ext3_splice_branch(handle_t *handle, struct inode *inode,
721                         long block, Indirect *where, int num, int blks)
722 {
723         int i;
724         int err = 0;
725         struct ext3_block_alloc_info *block_i;
726         ext3_fsblk_t current_block;
727         struct ext3_inode_info *ei = EXT3_I(inode);
728
729         block_i = ei->i_block_alloc_info;
730         /*
731          * If we're splicing into a [td]indirect block (as opposed to the
732          * inode) then we need to get write access to the [td]indirect block
733          * before the splice.
734          */
735         if (where->bh) {
736                 BUFFER_TRACE(where->bh, "get_write_access");
737                 err = ext3_journal_get_write_access(handle, where->bh);
738                 if (err)
739                         goto err_out;
740         }
741         /* That's it */
742
743         *where->p = where->key;
744
745         /*
746          * Update the host buffer_head or inode to point to more just allocated
747          * direct blocks blocks
748          */
749         if (num == 0 && blks > 1) {
750                 current_block = le32_to_cpu(where->key) + 1;
751                 for (i = 1; i < blks; i++)
752                         *(where->p + i ) = cpu_to_le32(current_block++);
753         }
754
755         /*
756          * update the most recently allocated logical & physical block
757          * in i_block_alloc_info, to assist find the proper goal block for next
758          * allocation
759          */
760         if (block_i) {
761                 block_i->last_alloc_logical_block = block + blks - 1;
762                 block_i->last_alloc_physical_block =
763                                 le32_to_cpu(where[num].key) + blks - 1;
764         }
765
766         /* We are done with atomic stuff, now do the rest of housekeeping */
767
768         inode->i_ctime = CURRENT_TIME_SEC;
769         ext3_mark_inode_dirty(handle, inode);
770         /* ext3_mark_inode_dirty already updated i_sync_tid */
771         atomic_set(&ei->i_datasync_tid, handle->h_transaction->t_tid);
772
773         /* had we spliced it onto indirect block? */
774         if (where->bh) {
775                 /*
776                  * If we spliced it onto an indirect block, we haven't
777                  * altered the inode.  Note however that if it is being spliced
778                  * onto an indirect block at the very end of the file (the
779                  * file is growing) then we *will* alter the inode to reflect
780                  * the new i_size.  But that is not done here - it is done in
781                  * generic_commit_write->__mark_inode_dirty->ext3_dirty_inode.
782                  */
783                 jbd_debug(5, "splicing indirect only\n");
784                 BUFFER_TRACE(where->bh, "call ext3_journal_dirty_metadata");
785                 err = ext3_journal_dirty_metadata(handle, where->bh);
786                 if (err)
787                         goto err_out;
788         } else {
789                 /*
790                  * OK, we spliced it into the inode itself on a direct block.
791                  * Inode was dirtied above.
792                  */
793                 jbd_debug(5, "splicing direct\n");
794         }
795         return err;
796
797 err_out:
798         for (i = 1; i <= num; i++) {
799                 BUFFER_TRACE(where[i].bh, "call journal_forget");
800                 ext3_journal_forget(handle, where[i].bh);
801                 ext3_free_blocks(handle,inode,le32_to_cpu(where[i-1].key),1);
802         }
803         ext3_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks);
804
805         return err;
806 }
807
808 /*
809  * Allocation strategy is simple: if we have to allocate something, we will
810  * have to go the whole way to leaf. So let's do it before attaching anything
811  * to tree, set linkage between the newborn blocks, write them if sync is
812  * required, recheck the path, free and repeat if check fails, otherwise
813  * set the last missing link (that will protect us from any truncate-generated
814  * removals - all blocks on the path are immune now) and possibly force the
815  * write on the parent block.
816  * That has a nice additional property: no special recovery from the failed
817  * allocations is needed - we simply release blocks and do not touch anything
818  * reachable from inode.
819  *
820  * `handle' can be NULL if create == 0.
821  *
822  * The BKL may not be held on entry here.  Be sure to take it early.
823  * return > 0, # of blocks mapped or allocated.
824  * return = 0, if plain lookup failed.
825  * return < 0, error case.
826  */
827 int ext3_get_blocks_handle(handle_t *handle, struct inode *inode,
828                 sector_t iblock, unsigned long maxblocks,
829                 struct buffer_head *bh_result,
830                 int create)
831 {
832         int err = -EIO;
833         int offsets[4];
834         Indirect chain[4];
835         Indirect *partial;
836         ext3_fsblk_t goal;
837         int indirect_blks;
838         int blocks_to_boundary = 0;
839         int depth;
840         struct ext3_inode_info *ei = EXT3_I(inode);
841         int count = 0;
842         ext3_fsblk_t first_block = 0;
843
844
845         J_ASSERT(handle != NULL || create == 0);
846         depth = ext3_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
847
848         if (depth == 0)
849                 goto out;
850
851         partial = ext3_get_branch(inode, depth, offsets, chain, &err);
852
853         /* Simplest case - block found, no allocation needed */
854         if (!partial) {
855                 first_block = le32_to_cpu(chain[depth - 1].key);
856                 clear_buffer_new(bh_result);
857                 count++;
858                 /*map more blocks*/
859                 while (count < maxblocks && count <= blocks_to_boundary) {
860                         ext3_fsblk_t blk;
861
862                         if (!verify_chain(chain, chain + depth - 1)) {
863                                 /*
864                                  * Indirect block might be removed by
865                                  * truncate while we were reading it.
866                                  * Handling of that case: forget what we've
867                                  * got now. Flag the err as EAGAIN, so it
868                                  * will reread.
869                                  */
870                                 err = -EAGAIN;
871                                 count = 0;
872                                 break;
873                         }
874                         blk = le32_to_cpu(*(chain[depth-1].p + count));
875
876                         if (blk == first_block + count)
877                                 count++;
878                         else
879                                 break;
880                 }
881                 if (err != -EAGAIN)
882                         goto got_it;
883         }
884
885         /* Next simple case - plain lookup or failed read of indirect block */
886         if (!create || err == -EIO)
887                 goto cleanup;
888
889         mutex_lock(&ei->truncate_mutex);
890
891         /*
892          * If the indirect block is missing while we are reading
893          * the chain(ext3_get_branch() returns -EAGAIN err), or
894          * if the chain has been changed after we grab the semaphore,
895          * (either because another process truncated this branch, or
896          * another get_block allocated this branch) re-grab the chain to see if
897          * the request block has been allocated or not.
898          *
899          * Since we already block the truncate/other get_block
900          * at this point, we will have the current copy of the chain when we
901          * splice the branch into the tree.
902          */
903         if (err == -EAGAIN || !verify_chain(chain, partial)) {
904                 while (partial > chain) {
905                         brelse(partial->bh);
906                         partial--;
907                 }
908                 partial = ext3_get_branch(inode, depth, offsets, chain, &err);
909                 if (!partial) {
910                         count++;
911                         mutex_unlock(&ei->truncate_mutex);
912                         if (err)
913                                 goto cleanup;
914                         clear_buffer_new(bh_result);
915                         goto got_it;
916                 }
917         }
918
919         /*
920          * Okay, we need to do block allocation.  Lazily initialize the block
921          * allocation info here if necessary
922         */
923         if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
924                 ext3_init_block_alloc_info(inode);
925
926         goal = ext3_find_goal(inode, iblock, partial);
927
928         /* the number of blocks need to allocate for [d,t]indirect blocks */
929         indirect_blks = (chain + depth) - partial - 1;
930
931         /*
932          * Next look up the indirect map to count the totoal number of
933          * direct blocks to allocate for this branch.
934          */
935         count = ext3_blks_to_allocate(partial, indirect_blks,
936                                         maxblocks, blocks_to_boundary);
937         /*
938          * Block out ext3_truncate while we alter the tree
939          */
940         err = ext3_alloc_branch(handle, inode, indirect_blks, &count, goal,
941                                 offsets + (partial - chain), partial);
942
943         /*
944          * The ext3_splice_branch call will free and forget any buffers
945          * on the new chain if there is a failure, but that risks using
946          * up transaction credits, especially for bitmaps where the
947          * credits cannot be returned.  Can we handle this somehow?  We
948          * may need to return -EAGAIN upwards in the worst case.  --sct
949          */
950         if (!err)
951                 err = ext3_splice_branch(handle, inode, iblock,
952                                         partial, indirect_blks, count);
953         mutex_unlock(&ei->truncate_mutex);
954         if (err)
955                 goto cleanup;
956
957         set_buffer_new(bh_result);
958 got_it:
959         map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
960         if (count > blocks_to_boundary)
961                 set_buffer_boundary(bh_result);
962         err = count;
963         /* Clean up and exit */
964         partial = chain + depth - 1;    /* the whole chain */
965 cleanup:
966         while (partial > chain) {
967                 BUFFER_TRACE(partial->bh, "call brelse");
968                 brelse(partial->bh);
969                 partial--;
970         }
971         BUFFER_TRACE(bh_result, "returned");
972 out:
973         return err;
974 }
975
976 /* Maximum number of blocks we map for direct IO at once. */
977 #define DIO_MAX_BLOCKS 4096
978 /*
979  * Number of credits we need for writing DIO_MAX_BLOCKS:
980  * We need sb + group descriptor + bitmap + inode -> 4
981  * For B blocks with A block pointers per block we need:
982  * 1 (triple ind.) + (B/A/A + 2) (doubly ind.) + (B/A + 2) (indirect).
983  * If we plug in 4096 for B and 256 for A (for 1KB block size), we get 25.
984  */
985 #define DIO_CREDITS 25
986
987 static int ext3_get_block(struct inode *inode, sector_t iblock,
988                         struct buffer_head *bh_result, int create)
989 {
990         handle_t *handle = ext3_journal_current_handle();
991         int ret = 0, started = 0;
992         unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
993
994         if (create && !handle) {        /* Direct IO write... */
995                 if (max_blocks > DIO_MAX_BLOCKS)
996                         max_blocks = DIO_MAX_BLOCKS;
997                 handle = ext3_journal_start(inode, DIO_CREDITS +
998                                 EXT3_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb));
999                 if (IS_ERR(handle)) {
1000                         ret = PTR_ERR(handle);
1001                         goto out;
1002                 }
1003                 started = 1;
1004         }
1005
1006         ret = ext3_get_blocks_handle(handle, inode, iblock,
1007                                         max_blocks, bh_result, create);
1008         if (ret > 0) {
1009                 bh_result->b_size = (ret << inode->i_blkbits);
1010                 ret = 0;
1011         }
1012         if (started)
1013                 ext3_journal_stop(handle);
1014 out:
1015         return ret;
1016 }
1017
1018 int ext3_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
1019                 u64 start, u64 len)
1020 {
1021         return generic_block_fiemap(inode, fieinfo, start, len,
1022                                     ext3_get_block);
1023 }
1024
1025 /*
1026  * `handle' can be NULL if create is zero
1027  */
1028 struct buffer_head *ext3_getblk(handle_t *handle, struct inode *inode,
1029                                 long block, int create, int *errp)
1030 {
1031         struct buffer_head dummy;
1032         int fatal = 0, err;
1033
1034         J_ASSERT(handle != NULL || create == 0);
1035
1036         dummy.b_state = 0;
1037         dummy.b_blocknr = -1000;
1038         buffer_trace_init(&dummy.b_history);
1039         err = ext3_get_blocks_handle(handle, inode, block, 1,
1040                                         &dummy, create);
1041         /*
1042          * ext3_get_blocks_handle() returns number of blocks
1043          * mapped. 0 in case of a HOLE.
1044          */
1045         if (err > 0) {
1046                 if (err > 1)
1047                         WARN_ON(1);
1048                 err = 0;
1049         }
1050         *errp = err;
1051         if (!err && buffer_mapped(&dummy)) {
1052                 struct buffer_head *bh;
1053                 bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
1054                 if (!bh) {
1055                         *errp = -EIO;
1056                         goto err;
1057                 }
1058                 if (buffer_new(&dummy)) {
1059                         J_ASSERT(create != 0);
1060                         J_ASSERT(handle != NULL);
1061
1062                         /*
1063                          * Now that we do not always journal data, we should
1064                          * keep in mind whether this should always journal the
1065                          * new buffer as metadata.  For now, regular file
1066                          * writes use ext3_get_block instead, so it's not a
1067                          * problem.
1068                          */
1069                         lock_buffer(bh);
1070                         BUFFER_TRACE(bh, "call get_create_access");
1071                         fatal = ext3_journal_get_create_access(handle, bh);
1072                         if (!fatal && !buffer_uptodate(bh)) {
1073                                 memset(bh->b_data,0,inode->i_sb->s_blocksize);
1074                                 set_buffer_uptodate(bh);
1075                         }
1076                         unlock_buffer(bh);
1077                         BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
1078                         err = ext3_journal_dirty_metadata(handle, bh);
1079                         if (!fatal)
1080                                 fatal = err;
1081                 } else {
1082                         BUFFER_TRACE(bh, "not a new buffer");
1083                 }
1084                 if (fatal) {
1085                         *errp = fatal;
1086                         brelse(bh);
1087                         bh = NULL;
1088                 }
1089                 return bh;
1090         }
1091 err:
1092         return NULL;
1093 }
1094
1095 struct buffer_head *ext3_bread(handle_t *handle, struct inode *inode,
1096                                int block, int create, int *err)
1097 {
1098         struct buffer_head * bh;
1099
1100         bh = ext3_getblk(handle, inode, block, create, err);
1101         if (!bh)
1102                 return bh;
1103         if (buffer_uptodate(bh))
1104                 return bh;
1105         ll_rw_block(READ_META, 1, &bh);
1106         wait_on_buffer(bh);
1107         if (buffer_uptodate(bh))
1108                 return bh;
1109         put_bh(bh);
1110         *err = -EIO;
1111         return NULL;
1112 }
1113
1114 static int walk_page_buffers(   handle_t *handle,
1115                                 struct buffer_head *head,
1116                                 unsigned from,
1117                                 unsigned to,
1118                                 int *partial,
1119                                 int (*fn)(      handle_t *handle,
1120                                                 struct buffer_head *bh))
1121 {
1122         struct buffer_head *bh;
1123         unsigned block_start, block_end;
1124         unsigned blocksize = head->b_size;
1125         int err, ret = 0;
1126         struct buffer_head *next;
1127
1128         for (   bh = head, block_start = 0;
1129                 ret == 0 && (bh != head || !block_start);
1130                 block_start = block_end, bh = next)
1131         {
1132                 next = bh->b_this_page;
1133                 block_end = block_start + blocksize;
1134                 if (block_end <= from || block_start >= to) {
1135                         if (partial && !buffer_uptodate(bh))
1136                                 *partial = 1;
1137                         continue;
1138                 }
1139                 err = (*fn)(handle, bh);
1140                 if (!ret)
1141                         ret = err;
1142         }
1143         return ret;
1144 }
1145
1146 /*
1147  * To preserve ordering, it is essential that the hole instantiation and
1148  * the data write be encapsulated in a single transaction.  We cannot
1149  * close off a transaction and start a new one between the ext3_get_block()
1150  * and the commit_write().  So doing the journal_start at the start of
1151  * prepare_write() is the right place.
1152  *
1153  * Also, this function can nest inside ext3_writepage() ->
1154  * block_write_full_page(). In that case, we *know* that ext3_writepage()
1155  * has generated enough buffer credits to do the whole page.  So we won't
1156  * block on the journal in that case, which is good, because the caller may
1157  * be PF_MEMALLOC.
1158  *
1159  * By accident, ext3 can be reentered when a transaction is open via
1160  * quota file writes.  If we were to commit the transaction while thus
1161  * reentered, there can be a deadlock - we would be holding a quota
1162  * lock, and the commit would never complete if another thread had a
1163  * transaction open and was blocking on the quota lock - a ranking
1164  * violation.
1165  *
1166  * So what we do is to rely on the fact that journal_stop/journal_start
1167  * will _not_ run commit under these circumstances because handle->h_ref
1168  * is elevated.  We'll still have enough credits for the tiny quotafile
1169  * write.
1170  */
1171 static int do_journal_get_write_access(handle_t *handle,
1172                                         struct buffer_head *bh)
1173 {
1174         int dirty = buffer_dirty(bh);
1175         int ret;
1176
1177         if (!buffer_mapped(bh) || buffer_freed(bh))
1178                 return 0;
1179         /*
1180          * __block_prepare_write() could have dirtied some buffers. Clean
1181          * the dirty bit as jbd2_journal_get_write_access() could complain
1182          * otherwise about fs integrity issues. Setting of the dirty bit
1183          * by __block_prepare_write() isn't a real problem here as we clear
1184          * the bit before releasing a page lock and thus writeback cannot
1185          * ever write the buffer.
1186          */
1187         if (dirty)
1188                 clear_buffer_dirty(bh);
1189         ret = ext3_journal_get_write_access(handle, bh);
1190         if (!ret && dirty)
1191                 ret = ext3_journal_dirty_metadata(handle, bh);
1192         return ret;
1193 }
1194
1195 /*
1196  * Truncate blocks that were not used by write. We have to truncate the
1197  * pagecache as well so that corresponding buffers get properly unmapped.
1198  */
1199 static void ext3_truncate_failed_write(struct inode *inode)
1200 {
1201         truncate_inode_pages(inode->i_mapping, inode->i_size);
1202         ext3_truncate(inode);
1203 }
1204
1205 static int ext3_write_begin(struct file *file, struct address_space *mapping,
1206                                 loff_t pos, unsigned len, unsigned flags,
1207                                 struct page **pagep, void **fsdata)
1208 {
1209         struct inode *inode = mapping->host;
1210         int ret;
1211         handle_t *handle;
1212         int retries = 0;
1213         struct page *page;
1214         pgoff_t index;
1215         unsigned from, to;
1216         /* Reserve one block more for addition to orphan list in case
1217          * we allocate blocks but write fails for some reason */
1218         int needed_blocks = ext3_writepage_trans_blocks(inode) + 1;
1219
1220         index = pos >> PAGE_CACHE_SHIFT;
1221         from = pos & (PAGE_CACHE_SIZE - 1);
1222         to = from + len;
1223
1224 retry:
1225         page = grab_cache_page_write_begin(mapping, index, flags);
1226         if (!page)
1227                 return -ENOMEM;
1228         *pagep = page;
1229
1230         handle = ext3_journal_start(inode, needed_blocks);
1231         if (IS_ERR(handle)) {
1232                 unlock_page(page);
1233                 page_cache_release(page);
1234                 ret = PTR_ERR(handle);
1235                 goto out;
1236         }
1237         ret = __block_write_begin(page, pos, len, ext3_get_block);
1238         if (ret)
1239                 goto write_begin_failed;
1240
1241         if (ext3_should_journal_data(inode)) {
1242                 ret = walk_page_buffers(handle, page_buffers(page),
1243                                 from, to, NULL, do_journal_get_write_access);
1244         }
1245 write_begin_failed:
1246         if (ret) {
1247                 /*
1248                  * block_write_begin may have instantiated a few blocks
1249                  * outside i_size.  Trim these off again. Don't need
1250                  * i_size_read because we hold i_mutex.
1251                  *
1252                  * Add inode to orphan list in case we crash before truncate
1253                  * finishes. Do this only if ext3_can_truncate() agrees so
1254                  * that orphan processing code is happy.
1255                  */
1256                 if (pos + len > inode->i_size && ext3_can_truncate(inode))
1257                         ext3_orphan_add(handle, inode);
1258                 ext3_journal_stop(handle);
1259                 unlock_page(page);
1260                 page_cache_release(page);
1261                 if (pos + len > inode->i_size)
1262                         ext3_truncate_failed_write(inode);
1263         }
1264         if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
1265                 goto retry;
1266 out:
1267         return ret;
1268 }
1269
1270
1271 int ext3_journal_dirty_data(handle_t *handle, struct buffer_head *bh)
1272 {
1273         int err = journal_dirty_data(handle, bh);
1274         if (err)
1275                 ext3_journal_abort_handle(__func__, __func__,
1276                                                 bh, handle, err);
1277         return err;
1278 }
1279
1280 /* For ordered writepage and write_end functions */
1281 static int journal_dirty_data_fn(handle_t *handle, struct buffer_head *bh)
1282 {
1283         /*
1284          * Write could have mapped the buffer but it didn't copy the data in
1285          * yet. So avoid filing such buffer into a transaction.
1286          */
1287         if (buffer_mapped(bh) && buffer_uptodate(bh))
1288                 return ext3_journal_dirty_data(handle, bh);
1289         return 0;
1290 }
1291
1292 /* For write_end() in data=journal mode */
1293 static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1294 {
1295         if (!buffer_mapped(bh) || buffer_freed(bh))
1296                 return 0;
1297         set_buffer_uptodate(bh);
1298         return ext3_journal_dirty_metadata(handle, bh);
1299 }
1300
1301 /*
1302  * This is nasty and subtle: ext3_write_begin() could have allocated blocks
1303  * for the whole page but later we failed to copy the data in. Update inode
1304  * size according to what we managed to copy. The rest is going to be
1305  * truncated in write_end function.
1306  */
1307 static void update_file_sizes(struct inode *inode, loff_t pos, unsigned copied)
1308 {
1309         /* What matters to us is i_disksize. We don't write i_size anywhere */
1310         if (pos + copied > inode->i_size)
1311                 i_size_write(inode, pos + copied);
1312         if (pos + copied > EXT3_I(inode)->i_disksize) {
1313                 EXT3_I(inode)->i_disksize = pos + copied;
1314                 mark_inode_dirty(inode);
1315         }
1316 }
1317
1318 /*
1319  * We need to pick up the new inode size which generic_commit_write gave us
1320  * `file' can be NULL - eg, when called from page_symlink().
1321  *
1322  * ext3 never places buffers on inode->i_mapping->private_list.  metadata
1323  * buffers are managed internally.
1324  */
1325 static int ext3_ordered_write_end(struct file *file,
1326                                 struct address_space *mapping,
1327                                 loff_t pos, unsigned len, unsigned copied,
1328                                 struct page *page, void *fsdata)
1329 {
1330         handle_t *handle = ext3_journal_current_handle();
1331         struct inode *inode = file->f_mapping->host;
1332         unsigned from, to;
1333         int ret = 0, ret2;
1334
1335         copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
1336
1337         from = pos & (PAGE_CACHE_SIZE - 1);
1338         to = from + copied;
1339         ret = walk_page_buffers(handle, page_buffers(page),
1340                 from, to, NULL, journal_dirty_data_fn);
1341
1342         if (ret == 0)
1343                 update_file_sizes(inode, pos, copied);
1344         /*
1345          * There may be allocated blocks outside of i_size because
1346          * we failed to copy some data. Prepare for truncate.
1347          */
1348         if (pos + len > inode->i_size && ext3_can_truncate(inode))
1349                 ext3_orphan_add(handle, inode);
1350         ret2 = ext3_journal_stop(handle);
1351         if (!ret)
1352                 ret = ret2;
1353         unlock_page(page);
1354         page_cache_release(page);
1355
1356         if (pos + len > inode->i_size)
1357                 ext3_truncate_failed_write(inode);
1358         return ret ? ret : copied;
1359 }
1360
1361 static int ext3_writeback_write_end(struct file *file,
1362                                 struct address_space *mapping,
1363                                 loff_t pos, unsigned len, unsigned copied,
1364                                 struct page *page, void *fsdata)
1365 {
1366         handle_t *handle = ext3_journal_current_handle();
1367         struct inode *inode = file->f_mapping->host;
1368         int ret;
1369
1370         copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
1371         update_file_sizes(inode, pos, copied);
1372         /*
1373          * There may be allocated blocks outside of i_size because
1374          * we failed to copy some data. Prepare for truncate.
1375          */
1376         if (pos + len > inode->i_size && ext3_can_truncate(inode))
1377                 ext3_orphan_add(handle, inode);
1378         ret = ext3_journal_stop(handle);
1379         unlock_page(page);
1380         page_cache_release(page);
1381
1382         if (pos + len > inode->i_size)
1383                 ext3_truncate_failed_write(inode);
1384         return ret ? ret : copied;
1385 }
1386
1387 static int ext3_journalled_write_end(struct file *file,
1388                                 struct address_space *mapping,
1389                                 loff_t pos, unsigned len, unsigned copied,
1390                                 struct page *page, void *fsdata)
1391 {
1392         handle_t *handle = ext3_journal_current_handle();
1393         struct inode *inode = mapping->host;
1394         int ret = 0, ret2;
1395         int partial = 0;
1396         unsigned from, to;
1397
1398         from = pos & (PAGE_CACHE_SIZE - 1);
1399         to = from + len;
1400
1401         if (copied < len) {
1402                 if (!PageUptodate(page))
1403                         copied = 0;
1404                 page_zero_new_buffers(page, from + copied, to);
1405                 to = from + copied;
1406         }
1407
1408         ret = walk_page_buffers(handle, page_buffers(page), from,
1409                                 to, &partial, write_end_fn);
1410         if (!partial)
1411                 SetPageUptodate(page);
1412
1413         if (pos + copied > inode->i_size)
1414                 i_size_write(inode, pos + copied);
1415         /*
1416          * There may be allocated blocks outside of i_size because
1417          * we failed to copy some data. Prepare for truncate.
1418          */
1419         if (pos + len > inode->i_size && ext3_can_truncate(inode))
1420                 ext3_orphan_add(handle, inode);
1421         ext3_set_inode_state(inode, EXT3_STATE_JDATA);
1422         if (inode->i_size > EXT3_I(inode)->i_disksize) {
1423                 EXT3_I(inode)->i_disksize = inode->i_size;
1424                 ret2 = ext3_mark_inode_dirty(handle, inode);
1425                 if (!ret)
1426                         ret = ret2;
1427         }
1428
1429         ret2 = ext3_journal_stop(handle);
1430         if (!ret)
1431                 ret = ret2;
1432         unlock_page(page);
1433         page_cache_release(page);
1434
1435         if (pos + len > inode->i_size)
1436                 ext3_truncate_failed_write(inode);
1437         return ret ? ret : copied;
1438 }
1439
1440 /*
1441  * bmap() is special.  It gets used by applications such as lilo and by
1442  * the swapper to find the on-disk block of a specific piece of data.
1443  *
1444  * Naturally, this is dangerous if the block concerned is still in the
1445  * journal.  If somebody makes a swapfile on an ext3 data-journaling
1446  * filesystem and enables swap, then they may get a nasty shock when the
1447  * data getting swapped to that swapfile suddenly gets overwritten by
1448  * the original zero's written out previously to the journal and
1449  * awaiting writeback in the kernel's buffer cache.
1450  *
1451  * So, if we see any bmap calls here on a modified, data-journaled file,
1452  * take extra steps to flush any blocks which might be in the cache.
1453  */
1454 static sector_t ext3_bmap(struct address_space *mapping, sector_t block)
1455 {
1456         struct inode *inode = mapping->host;
1457         journal_t *journal;
1458         int err;
1459
1460         if (ext3_test_inode_state(inode, EXT3_STATE_JDATA)) {
1461                 /*
1462                  * This is a REALLY heavyweight approach, but the use of
1463                  * bmap on dirty files is expected to be extremely rare:
1464                  * only if we run lilo or swapon on a freshly made file
1465                  * do we expect this to happen.
1466                  *
1467                  * (bmap requires CAP_SYS_RAWIO so this does not
1468                  * represent an unprivileged user DOS attack --- we'd be
1469                  * in trouble if mortal users could trigger this path at
1470                  * will.)
1471                  *
1472                  * NB. EXT3_STATE_JDATA is not set on files other than
1473                  * regular files.  If somebody wants to bmap a directory
1474                  * or symlink and gets confused because the buffer
1475                  * hasn't yet been flushed to disk, they deserve
1476                  * everything they get.
1477                  */
1478
1479                 ext3_clear_inode_state(inode, EXT3_STATE_JDATA);
1480                 journal = EXT3_JOURNAL(inode);
1481                 journal_lock_updates(journal);
1482                 err = journal_flush(journal);
1483                 journal_unlock_updates(journal);
1484
1485                 if (err)
1486                         return 0;
1487         }
1488
1489         return generic_block_bmap(mapping,block,ext3_get_block);
1490 }
1491
1492 static int bget_one(handle_t *handle, struct buffer_head *bh)
1493 {
1494         get_bh(bh);
1495         return 0;
1496 }
1497
1498 static int bput_one(handle_t *handle, struct buffer_head *bh)
1499 {
1500         put_bh(bh);
1501         return 0;
1502 }
1503
1504 static int buffer_unmapped(handle_t *handle, struct buffer_head *bh)
1505 {
1506         return !buffer_mapped(bh);
1507 }
1508
1509 /*
1510  * Note that we always start a transaction even if we're not journalling
1511  * data.  This is to preserve ordering: any hole instantiation within
1512  * __block_write_full_page -> ext3_get_block() should be journalled
1513  * along with the data so we don't crash and then get metadata which
1514  * refers to old data.
1515  *
1516  * In all journalling modes block_write_full_page() will start the I/O.
1517  *
1518  * Problem:
1519  *
1520  *      ext3_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
1521  *              ext3_writepage()
1522  *
1523  * Similar for:
1524  *
1525  *      ext3_file_write() -> generic_file_write() -> __alloc_pages() -> ...
1526  *
1527  * Same applies to ext3_get_block().  We will deadlock on various things like
1528  * lock_journal and i_truncate_mutex.
1529  *
1530  * Setting PF_MEMALLOC here doesn't work - too many internal memory
1531  * allocations fail.
1532  *
1533  * 16May01: If we're reentered then journal_current_handle() will be
1534  *          non-zero. We simply *return*.
1535  *
1536  * 1 July 2001: @@@ FIXME:
1537  *   In journalled data mode, a data buffer may be metadata against the
1538  *   current transaction.  But the same file is part of a shared mapping
1539  *   and someone does a writepage() on it.
1540  *
1541  *   We will move the buffer onto the async_data list, but *after* it has
1542  *   been dirtied. So there's a small window where we have dirty data on
1543  *   BJ_Metadata.
1544  *
1545  *   Note that this only applies to the last partial page in the file.  The
1546  *   bit which block_write_full_page() uses prepare/commit for.  (That's
1547  *   broken code anyway: it's wrong for msync()).
1548  *
1549  *   It's a rare case: affects the final partial page, for journalled data
1550  *   where the file is subject to bith write() and writepage() in the same
1551  *   transction.  To fix it we'll need a custom block_write_full_page().
1552  *   We'll probably need that anyway for journalling writepage() output.
1553  *
1554  * We don't honour synchronous mounts for writepage().  That would be
1555  * disastrous.  Any write() or metadata operation will sync the fs for
1556  * us.
1557  *
1558  * AKPM2: if all the page's buffers are mapped to disk and !data=journal,
1559  * we don't need to open a transaction here.
1560  */
1561 static int ext3_ordered_writepage(struct page *page,
1562                                 struct writeback_control *wbc)
1563 {
1564         struct inode *inode = page->mapping->host;
1565         struct buffer_head *page_bufs;
1566         handle_t *handle = NULL;
1567         int ret = 0;
1568         int err;
1569
1570         J_ASSERT(PageLocked(page));
1571         WARN_ON_ONCE(IS_RDONLY(inode));
1572
1573         /*
1574          * We give up here if we're reentered, because it might be for a
1575          * different filesystem.
1576          */
1577         if (ext3_journal_current_handle())
1578                 goto out_fail;
1579
1580         if (!page_has_buffers(page)) {
1581                 create_empty_buffers(page, inode->i_sb->s_blocksize,
1582                                 (1 << BH_Dirty)|(1 << BH_Uptodate));
1583                 page_bufs = page_buffers(page);
1584         } else {
1585                 page_bufs = page_buffers(page);
1586                 if (!walk_page_buffers(NULL, page_bufs, 0, PAGE_CACHE_SIZE,
1587                                        NULL, buffer_unmapped)) {
1588                         /* Provide NULL get_block() to catch bugs if buffers
1589                          * weren't really mapped */
1590                         return block_write_full_page(page, NULL, wbc);
1591                 }
1592         }
1593         handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
1594
1595         if (IS_ERR(handle)) {
1596                 ret = PTR_ERR(handle);
1597                 goto out_fail;
1598         }
1599
1600         walk_page_buffers(handle, page_bufs, 0,
1601                         PAGE_CACHE_SIZE, NULL, bget_one);
1602
1603         ret = block_write_full_page(page, ext3_get_block, wbc);
1604
1605         /*
1606          * The page can become unlocked at any point now, and
1607          * truncate can then come in and change things.  So we
1608          * can't touch *page from now on.  But *page_bufs is
1609          * safe due to elevated refcount.
1610          */
1611
1612         /*
1613          * And attach them to the current transaction.  But only if
1614          * block_write_full_page() succeeded.  Otherwise they are unmapped,
1615          * and generally junk.
1616          */
1617         if (ret == 0) {
1618                 err = walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE,
1619                                         NULL, journal_dirty_data_fn);
1620                 if (!ret)
1621                         ret = err;
1622         }
1623         walk_page_buffers(handle, page_bufs, 0,
1624                         PAGE_CACHE_SIZE, NULL, bput_one);
1625         err = ext3_journal_stop(handle);
1626         if (!ret)
1627                 ret = err;
1628         return ret;
1629
1630 out_fail:
1631         redirty_page_for_writepage(wbc, page);
1632         unlock_page(page);
1633         return ret;
1634 }
1635
1636 static int ext3_writeback_writepage(struct page *page,
1637                                 struct writeback_control *wbc)
1638 {
1639         struct inode *inode = page->mapping->host;
1640         handle_t *handle = NULL;
1641         int ret = 0;
1642         int err;
1643
1644         J_ASSERT(PageLocked(page));
1645         WARN_ON_ONCE(IS_RDONLY(inode));
1646
1647         if (ext3_journal_current_handle())
1648                 goto out_fail;
1649
1650         if (page_has_buffers(page)) {
1651                 if (!walk_page_buffers(NULL, page_buffers(page), 0,
1652                                       PAGE_CACHE_SIZE, NULL, buffer_unmapped)) {
1653                         /* Provide NULL get_block() to catch bugs if buffers
1654                          * weren't really mapped */
1655                         return block_write_full_page(page, NULL, wbc);
1656                 }
1657         }
1658
1659         handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
1660         if (IS_ERR(handle)) {
1661                 ret = PTR_ERR(handle);
1662                 goto out_fail;
1663         }
1664
1665         ret = block_write_full_page(page, ext3_get_block, wbc);
1666
1667         err = ext3_journal_stop(handle);
1668         if (!ret)
1669                 ret = err;
1670         return ret;
1671
1672 out_fail:
1673         redirty_page_for_writepage(wbc, page);
1674         unlock_page(page);
1675         return ret;
1676 }
1677
1678 static int ext3_journalled_writepage(struct page *page,
1679                                 struct writeback_control *wbc)
1680 {
1681         struct inode *inode = page->mapping->host;
1682         handle_t *handle = NULL;
1683         int ret = 0;
1684         int err;
1685
1686         J_ASSERT(PageLocked(page));
1687         WARN_ON_ONCE(IS_RDONLY(inode));
1688
1689         if (ext3_journal_current_handle())
1690                 goto no_write;
1691
1692         handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
1693         if (IS_ERR(handle)) {
1694                 ret = PTR_ERR(handle);
1695                 goto no_write;
1696         }
1697
1698         if (!page_has_buffers(page) || PageChecked(page)) {
1699                 /*
1700                  * It's mmapped pagecache.  Add buffers and journal it.  There
1701                  * doesn't seem much point in redirtying the page here.
1702                  */
1703                 ClearPageChecked(page);
1704                 ret = __block_write_begin(page, 0, PAGE_CACHE_SIZE,
1705                                           ext3_get_block);
1706                 if (ret != 0) {
1707                         ext3_journal_stop(handle);
1708                         goto out_unlock;
1709                 }
1710                 ret = walk_page_buffers(handle, page_buffers(page), 0,
1711                         PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
1712
1713                 err = walk_page_buffers(handle, page_buffers(page), 0,
1714                                 PAGE_CACHE_SIZE, NULL, write_end_fn);
1715                 if (ret == 0)
1716                         ret = err;
1717                 ext3_set_inode_state(inode, EXT3_STATE_JDATA);
1718                 unlock_page(page);
1719         } else {
1720                 /*
1721                  * It may be a page full of checkpoint-mode buffers.  We don't
1722                  * really know unless we go poke around in the buffer_heads.
1723                  * But block_write_full_page will do the right thing.
1724                  */
1725                 ret = block_write_full_page(page, ext3_get_block, wbc);
1726         }
1727         err = ext3_journal_stop(handle);
1728         if (!ret)
1729                 ret = err;
1730 out:
1731         return ret;
1732
1733 no_write:
1734         redirty_page_for_writepage(wbc, page);
1735 out_unlock:
1736         unlock_page(page);
1737         goto out;
1738 }
1739
1740 static int ext3_readpage(struct file *file, struct page *page)
1741 {
1742         return mpage_readpage(page, ext3_get_block);
1743 }
1744
1745 static int
1746 ext3_readpages(struct file *file, struct address_space *mapping,
1747                 struct list_head *pages, unsigned nr_pages)
1748 {
1749         return mpage_readpages(mapping, pages, nr_pages, ext3_get_block);
1750 }
1751
1752 static void ext3_invalidatepage(struct page *page, unsigned long offset)
1753 {
1754         journal_t *journal = EXT3_JOURNAL(page->mapping->host);
1755
1756         /*
1757          * If it's a full truncate we just forget about the pending dirtying
1758          */
1759         if (offset == 0)
1760                 ClearPageChecked(page);
1761
1762         journal_invalidatepage(journal, page, offset);
1763 }
1764
1765 static int ext3_releasepage(struct page *page, gfp_t wait)
1766 {
1767         journal_t *journal = EXT3_JOURNAL(page->mapping->host);
1768
1769         WARN_ON(PageChecked(page));
1770         if (!page_has_buffers(page))
1771                 return 0;
1772         return journal_try_to_free_buffers(journal, page, wait);
1773 }
1774
1775 /*
1776  * If the O_DIRECT write will extend the file then add this inode to the
1777  * orphan list.  So recovery will truncate it back to the original size
1778  * if the machine crashes during the write.
1779  *
1780  * If the O_DIRECT write is intantiating holes inside i_size and the machine
1781  * crashes then stale disk data _may_ be exposed inside the file. But current
1782  * VFS code falls back into buffered path in that case so we are safe.
1783  */
1784 static ssize_t ext3_direct_IO(int rw, struct kiocb *iocb,
1785                         const struct iovec *iov, loff_t offset,
1786                         unsigned long nr_segs)
1787 {
1788         struct file *file = iocb->ki_filp;
1789         struct inode *inode = file->f_mapping->host;
1790         struct ext3_inode_info *ei = EXT3_I(inode);
1791         handle_t *handle;
1792         ssize_t ret;
1793         int orphan = 0;
1794         size_t count = iov_length(iov, nr_segs);
1795         int retries = 0;
1796
1797         if (rw == WRITE) {
1798                 loff_t final_size = offset + count;
1799
1800                 if (final_size > inode->i_size) {
1801                         /* Credits for sb + inode write */
1802                         handle = ext3_journal_start(inode, 2);
1803                         if (IS_ERR(handle)) {
1804                                 ret = PTR_ERR(handle);
1805                                 goto out;
1806                         }
1807                         ret = ext3_orphan_add(handle, inode);
1808                         if (ret) {
1809                                 ext3_journal_stop(handle);
1810                                 goto out;
1811                         }
1812                         orphan = 1;
1813                         ei->i_disksize = inode->i_size;
1814                         ext3_journal_stop(handle);
1815                 }
1816         }
1817
1818 retry:
1819         ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
1820                                  offset, nr_segs,
1821                                  ext3_get_block, NULL);
1822         /*
1823          * In case of error extending write may have instantiated a few
1824          * blocks outside i_size. Trim these off again.
1825          */
1826         if (unlikely((rw & WRITE) && ret < 0)) {
1827                 loff_t isize = i_size_read(inode);
1828                 loff_t end = offset + iov_length(iov, nr_segs);
1829
1830                 if (end > isize)
1831                         vmtruncate(inode, isize);
1832         }
1833         if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
1834                 goto retry;
1835
1836         if (orphan) {
1837                 int err;
1838
1839                 /* Credits for sb + inode write */
1840                 handle = ext3_journal_start(inode, 2);
1841                 if (IS_ERR(handle)) {
1842                         /* This is really bad luck. We've written the data
1843                          * but cannot extend i_size. Truncate allocated blocks
1844                          * and pretend the write failed... */
1845                         ext3_truncate(inode);
1846                         ret = PTR_ERR(handle);
1847                         goto out;
1848                 }
1849                 if (inode->i_nlink)
1850                         ext3_orphan_del(handle, inode);
1851                 if (ret > 0) {
1852                         loff_t end = offset + ret;
1853                         if (end > inode->i_size) {
1854                                 ei->i_disksize = end;
1855                                 i_size_write(inode, end);
1856                                 /*
1857                                  * We're going to return a positive `ret'
1858                                  * here due to non-zero-length I/O, so there's
1859                                  * no way of reporting error returns from
1860                                  * ext3_mark_inode_dirty() to userspace.  So
1861                                  * ignore it.
1862                                  */
1863                                 ext3_mark_inode_dirty(handle, inode);
1864                         }
1865                 }
1866                 err = ext3_journal_stop(handle);
1867                 if (ret == 0)
1868                         ret = err;
1869         }
1870 out:
1871         return ret;
1872 }
1873
1874 /*
1875  * Pages can be marked dirty completely asynchronously from ext3's journalling
1876  * activity.  By filemap_sync_pte(), try_to_unmap_one(), etc.  We cannot do
1877  * much here because ->set_page_dirty is called under VFS locks.  The page is
1878  * not necessarily locked.
1879  *
1880  * We cannot just dirty the page and leave attached buffers clean, because the
1881  * buffers' dirty state is "definitive".  We cannot just set the buffers dirty
1882  * or jbddirty because all the journalling code will explode.
1883  *
1884  * So what we do is to mark the page "pending dirty" and next time writepage
1885  * is called, propagate that into the buffers appropriately.
1886  */
1887 static int ext3_journalled_set_page_dirty(struct page *page)
1888 {
1889         SetPageChecked(page);
1890         return __set_page_dirty_nobuffers(page);
1891 }
1892
1893 static const struct address_space_operations ext3_ordered_aops = {
1894         .readpage               = ext3_readpage,
1895         .readpages              = ext3_readpages,
1896         .writepage              = ext3_ordered_writepage,
1897         .write_begin            = ext3_write_begin,
1898         .write_end              = ext3_ordered_write_end,
1899         .bmap                   = ext3_bmap,
1900         .invalidatepage         = ext3_invalidatepage,
1901         .releasepage            = ext3_releasepage,
1902         .direct_IO              = ext3_direct_IO,
1903         .migratepage            = buffer_migrate_page,
1904         .is_partially_uptodate  = block_is_partially_uptodate,
1905         .error_remove_page      = generic_error_remove_page,
1906 };
1907
1908 static const struct address_space_operations ext3_writeback_aops = {
1909         .readpage               = ext3_readpage,
1910         .readpages              = ext3_readpages,
1911         .writepage              = ext3_writeback_writepage,
1912         .write_begin            = ext3_write_begin,
1913         .write_end              = ext3_writeback_write_end,
1914         .bmap                   = ext3_bmap,
1915         .invalidatepage         = ext3_invalidatepage,
1916         .releasepage            = ext3_releasepage,
1917         .direct_IO              = ext3_direct_IO,
1918         .migratepage            = buffer_migrate_page,
1919         .is_partially_uptodate  = block_is_partially_uptodate,
1920         .error_remove_page      = generic_error_remove_page,
1921 };
1922
1923 static const struct address_space_operations ext3_journalled_aops = {
1924         .readpage               = ext3_readpage,
1925         .readpages              = ext3_readpages,
1926         .writepage              = ext3_journalled_writepage,
1927         .write_begin            = ext3_write_begin,
1928         .write_end              = ext3_journalled_write_end,
1929         .set_page_dirty         = ext3_journalled_set_page_dirty,
1930         .bmap                   = ext3_bmap,
1931         .invalidatepage         = ext3_invalidatepage,
1932         .releasepage            = ext3_releasepage,
1933         .is_partially_uptodate  = block_is_partially_uptodate,
1934         .error_remove_page      = generic_error_remove_page,
1935 };
1936
1937 void ext3_set_aops(struct inode *inode)
1938 {
1939         if (ext3_should_order_data(inode))
1940                 inode->i_mapping->a_ops = &ext3_ordered_aops;
1941         else if (ext3_should_writeback_data(inode))
1942                 inode->i_mapping->a_ops = &ext3_writeback_aops;
1943         else
1944                 inode->i_mapping->a_ops = &ext3_journalled_aops;
1945 }
1946
1947 /*
1948  * ext3_block_truncate_page() zeroes out a mapping from file offset `from'
1949  * up to the end of the block which corresponds to `from'.
1950  * This required during truncate. We need to physically zero the tail end
1951  * of that block so it doesn't yield old data if the file is later grown.
1952  */
1953 static int ext3_block_truncate_page(handle_t *handle, struct page *page,
1954                 struct address_space *mapping, loff_t from)
1955 {
1956         ext3_fsblk_t index = from >> PAGE_CACHE_SHIFT;
1957         unsigned offset = from & (PAGE_CACHE_SIZE-1);
1958         unsigned blocksize, iblock, length, pos;
1959         struct inode *inode = mapping->host;
1960         struct buffer_head *bh;
1961         int err = 0;
1962
1963         blocksize = inode->i_sb->s_blocksize;
1964         length = blocksize - (offset & (blocksize - 1));
1965         iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
1966
1967         if (!page_has_buffers(page))
1968                 create_empty_buffers(page, blocksize, 0);
1969
1970         /* Find the buffer that contains "offset" */
1971         bh = page_buffers(page);
1972         pos = blocksize;
1973         while (offset >= pos) {
1974                 bh = bh->b_this_page;
1975                 iblock++;
1976                 pos += blocksize;
1977         }
1978
1979         err = 0;
1980         if (buffer_freed(bh)) {
1981                 BUFFER_TRACE(bh, "freed: skip");
1982                 goto unlock;
1983         }
1984
1985         if (!buffer_mapped(bh)) {
1986                 BUFFER_TRACE(bh, "unmapped");
1987                 ext3_get_block(inode, iblock, bh, 0);
1988                 /* unmapped? It's a hole - nothing to do */
1989                 if (!buffer_mapped(bh)) {
1990                         BUFFER_TRACE(bh, "still unmapped");
1991                         goto unlock;
1992                 }
1993         }
1994
1995         /* Ok, it's mapped. Make sure it's up-to-date */
1996         if (PageUptodate(page))
1997                 set_buffer_uptodate(bh);
1998
1999         if (!buffer_uptodate(bh)) {
2000                 err = -EIO;
2001                 ll_rw_block(READ, 1, &bh);
2002                 wait_on_buffer(bh);
2003                 /* Uhhuh. Read error. Complain and punt. */
2004                 if (!buffer_uptodate(bh))
2005                         goto unlock;
2006         }
2007
2008         if (ext3_should_journal_data(inode)) {
2009                 BUFFER_TRACE(bh, "get write access");
2010                 err = ext3_journal_get_write_access(handle, bh);
2011                 if (err)
2012                         goto unlock;
2013         }
2014
2015         zero_user(page, offset, length);
2016         BUFFER_TRACE(bh, "zeroed end of block");
2017
2018         err = 0;
2019         if (ext3_should_journal_data(inode)) {
2020                 err = ext3_journal_dirty_metadata(handle, bh);
2021         } else {
2022                 if (ext3_should_order_data(inode))
2023                         err = ext3_journal_dirty_data(handle, bh);
2024                 mark_buffer_dirty(bh);
2025         }
2026
2027 unlock:
2028         unlock_page(page);
2029         page_cache_release(page);
2030         return err;
2031 }
2032
2033 /*
2034  * Probably it should be a library function... search for first non-zero word
2035  * or memcmp with zero_page, whatever is better for particular architecture.
2036  * Linus?
2037  */
2038 static inline int all_zeroes(__le32 *p, __le32 *q)
2039 {
2040         while (p < q)
2041                 if (*p++)
2042                         return 0;
2043         return 1;
2044 }
2045
2046 /**
2047  *      ext3_find_shared - find the indirect blocks for partial truncation.
2048  *      @inode:   inode in question
2049  *      @depth:   depth of the affected branch
2050  *      @offsets: offsets of pointers in that branch (see ext3_block_to_path)
2051  *      @chain:   place to store the pointers to partial indirect blocks
2052  *      @top:     place to the (detached) top of branch
2053  *
2054  *      This is a helper function used by ext3_truncate().
2055  *
2056  *      When we do truncate() we may have to clean the ends of several
2057  *      indirect blocks but leave the blocks themselves alive. Block is
2058  *      partially truncated if some data below the new i_size is referred
2059  *      from it (and it is on the path to the first completely truncated
2060  *      data block, indeed).  We have to free the top of that path along
2061  *      with everything to the right of the path. Since no allocation
2062  *      past the truncation point is possible until ext3_truncate()
2063  *      finishes, we may safely do the latter, but top of branch may
2064  *      require special attention - pageout below the truncation point
2065  *      might try to populate it.
2066  *
2067  *      We atomically detach the top of branch from the tree, store the
2068  *      block number of its root in *@top, pointers to buffer_heads of
2069  *      partially truncated blocks - in @chain[].bh and pointers to
2070  *      their last elements that should not be removed - in
2071  *      @chain[].p. Return value is the pointer to last filled element
2072  *      of @chain.
2073  *
2074  *      The work left to caller to do the actual freeing of subtrees:
2075  *              a) free the subtree starting from *@top
2076  *              b) free the subtrees whose roots are stored in
2077  *                      (@chain[i].p+1 .. end of @chain[i].bh->b_data)
2078  *              c) free the subtrees growing from the inode past the @chain[0].
2079  *                      (no partially truncated stuff there).  */
2080
2081 static Indirect *ext3_find_shared(struct inode *inode, int depth,
2082                         int offsets[4], Indirect chain[4], __le32 *top)
2083 {
2084         Indirect *partial, *p;
2085         int k, err;
2086
2087         *top = 0;
2088         /* Make k index the deepest non-null offset + 1 */
2089         for (k = depth; k > 1 && !offsets[k-1]; k--)
2090                 ;
2091         partial = ext3_get_branch(inode, k, offsets, chain, &err);
2092         /* Writer: pointers */
2093         if (!partial)
2094                 partial = chain + k-1;
2095         /*
2096          * If the branch acquired continuation since we've looked at it -
2097          * fine, it should all survive and (new) top doesn't belong to us.
2098          */
2099         if (!partial->key && *partial->p)
2100                 /* Writer: end */
2101                 goto no_top;
2102         for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
2103                 ;
2104         /*
2105          * OK, we've found the last block that must survive. The rest of our
2106          * branch should be detached before unlocking. However, if that rest
2107          * of branch is all ours and does not grow immediately from the inode
2108          * it's easier to cheat and just decrement partial->p.
2109          */
2110         if (p == chain + k - 1 && p > chain) {
2111                 p->p--;
2112         } else {
2113                 *top = *p->p;
2114                 /* Nope, don't do this in ext3.  Must leave the tree intact */
2115 #if 0
2116                 *p->p = 0;
2117 #endif
2118         }
2119         /* Writer: end */
2120
2121         while(partial > p) {
2122                 brelse(partial->bh);
2123                 partial--;
2124         }
2125 no_top:
2126         return partial;
2127 }
2128
2129 /*
2130  * Zero a number of block pointers in either an inode or an indirect block.
2131  * If we restart the transaction we must again get write access to the
2132  * indirect block for further modification.
2133  *
2134  * We release `count' blocks on disk, but (last - first) may be greater
2135  * than `count' because there can be holes in there.
2136  */
2137 static void ext3_clear_blocks(handle_t *handle, struct inode *inode,
2138                 struct buffer_head *bh, ext3_fsblk_t block_to_free,
2139                 unsigned long count, __le32 *first, __le32 *last)
2140 {
2141         __le32 *p;
2142         if (try_to_extend_transaction(handle, inode)) {
2143                 if (bh) {
2144                         BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
2145                         if (ext3_journal_dirty_metadata(handle, bh))
2146                                 return;
2147                 }
2148                 ext3_mark_inode_dirty(handle, inode);
2149                 truncate_restart_transaction(handle, inode);
2150                 if (bh) {
2151                         BUFFER_TRACE(bh, "retaking write access");
2152                         if (ext3_journal_get_write_access(handle, bh))
2153                                 return;
2154                 }
2155         }
2156
2157         /*
2158          * Any buffers which are on the journal will be in memory. We find
2159          * them on the hash table so journal_revoke() will run journal_forget()
2160          * on them.  We've already detached each block from the file, so
2161          * bforget() in journal_forget() should be safe.
2162          *
2163          * AKPM: turn on bforget in journal_forget()!!!
2164          */
2165         for (p = first; p < last; p++) {
2166                 u32 nr = le32_to_cpu(*p);
2167                 if (nr) {
2168                         struct buffer_head *bh;
2169
2170                         *p = 0;
2171                         bh = sb_find_get_block(inode->i_sb, nr);
2172                         ext3_forget(handle, 0, inode, bh, nr);
2173                 }
2174         }
2175
2176         ext3_free_blocks(handle, inode, block_to_free, count);
2177 }
2178
2179 /**
2180  * ext3_free_data - free a list of data blocks
2181  * @handle:     handle for this transaction
2182  * @inode:      inode we are dealing with
2183  * @this_bh:    indirect buffer_head which contains *@first and *@last
2184  * @first:      array of block numbers
2185  * @last:       points immediately past the end of array
2186  *
2187  * We are freeing all blocks referred from that array (numbers are stored as
2188  * little-endian 32-bit) and updating @inode->i_blocks appropriately.
2189  *
2190  * We accumulate contiguous runs of blocks to free.  Conveniently, if these
2191  * blocks are contiguous then releasing them at one time will only affect one
2192  * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
2193  * actually use a lot of journal space.
2194  *
2195  * @this_bh will be %NULL if @first and @last point into the inode's direct
2196  * block pointers.
2197  */
2198 static void ext3_free_data(handle_t *handle, struct inode *inode,
2199                            struct buffer_head *this_bh,
2200                            __le32 *first, __le32 *last)
2201 {
2202         ext3_fsblk_t block_to_free = 0;    /* Starting block # of a run */
2203         unsigned long count = 0;            /* Number of blocks in the run */
2204         __le32 *block_to_free_p = NULL;     /* Pointer into inode/ind
2205                                                corresponding to
2206                                                block_to_free */
2207         ext3_fsblk_t nr;                    /* Current block # */
2208         __le32 *p;                          /* Pointer into inode/ind
2209                                                for current block */
2210         int err;
2211
2212         if (this_bh) {                          /* For indirect block */
2213                 BUFFER_TRACE(this_bh, "get_write_access");
2214                 err = ext3_journal_get_write_access(handle, this_bh);
2215                 /* Important: if we can't update the indirect pointers
2216                  * to the blocks, we can't free them. */
2217                 if (err)
2218                         return;
2219         }
2220
2221         for (p = first; p < last; p++) {
2222                 nr = le32_to_cpu(*p);
2223                 if (nr) {
2224                         /* accumulate blocks to free if they're contiguous */
2225                         if (count == 0) {
2226                                 block_to_free = nr;
2227                                 block_to_free_p = p;
2228                                 count = 1;
2229                         } else if (nr == block_to_free + count) {
2230                                 count++;
2231                         } else {
2232                                 ext3_clear_blocks(handle, inode, this_bh,
2233                                                   block_to_free,
2234                                                   count, block_to_free_p, p);
2235                                 block_to_free = nr;
2236                                 block_to_free_p = p;
2237                                 count = 1;
2238                         }
2239                 }
2240         }
2241
2242         if (count > 0)
2243                 ext3_clear_blocks(handle, inode, this_bh, block_to_free,
2244                                   count, block_to_free_p, p);
2245
2246         if (this_bh) {
2247                 BUFFER_TRACE(this_bh, "call ext3_journal_dirty_metadata");
2248
2249                 /*
2250                  * The buffer head should have an attached journal head at this
2251                  * point. However, if the data is corrupted and an indirect
2252                  * block pointed to itself, it would have been detached when
2253                  * the block was cleared. Check for this instead of OOPSing.
2254                  */
2255                 if (bh2jh(this_bh))
2256                         ext3_journal_dirty_metadata(handle, this_bh);
2257                 else
2258                         ext3_error(inode->i_sb, "ext3_free_data",
2259                                    "circular indirect block detected, "
2260                                    "inode=%lu, block=%llu",
2261                                    inode->i_ino,
2262                                    (unsigned long long)this_bh->b_blocknr);
2263         }
2264 }
2265
2266 /**
2267  *      ext3_free_branches - free an array of branches
2268  *      @handle: JBD handle for this transaction
2269  *      @inode: inode we are dealing with
2270  *      @parent_bh: the buffer_head which contains *@first and *@last
2271  *      @first: array of block numbers
2272  *      @last:  pointer immediately past the end of array
2273  *      @depth: depth of the branches to free
2274  *
2275  *      We are freeing all blocks referred from these branches (numbers are
2276  *      stored as little-endian 32-bit) and updating @inode->i_blocks
2277  *      appropriately.
2278  */
2279 static void ext3_free_branches(handle_t *handle, struct inode *inode,
2280                                struct buffer_head *parent_bh,
2281                                __le32 *first, __le32 *last, int depth)
2282 {
2283         ext3_fsblk_t nr;
2284         __le32 *p;
2285
2286         if (is_handle_aborted(handle))
2287                 return;
2288
2289         if (depth--) {
2290                 struct buffer_head *bh;
2291                 int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
2292                 p = last;
2293                 while (--p >= first) {
2294                         nr = le32_to_cpu(*p);
2295                         if (!nr)
2296                                 continue;               /* A hole */
2297
2298                         /* Go read the buffer for the next level down */
2299                         bh = sb_bread(inode->i_sb, nr);
2300
2301                         /*
2302                          * A read failure? Report error and clear slot
2303                          * (should be rare).
2304                          */
2305                         if (!bh) {
2306                                 ext3_error(inode->i_sb, "ext3_free_branches",
2307                                            "Read failure, inode=%lu, block="E3FSBLK,
2308                                            inode->i_ino, nr);
2309                                 continue;
2310                         }
2311
2312                         /* This zaps the entire block.  Bottom up. */
2313                         BUFFER_TRACE(bh, "free child branches");
2314                         ext3_free_branches(handle, inode, bh,
2315                                            (__le32*)bh->b_data,
2316                                            (__le32*)bh->b_data + addr_per_block,
2317                                            depth);
2318
2319                         /*
2320                          * Everything below this this pointer has been
2321                          * released.  Now let this top-of-subtree go.
2322                          *
2323                          * We want the freeing of this indirect block to be
2324                          * atomic in the journal with the updating of the
2325                          * bitmap block which owns it.  So make some room in
2326                          * the journal.
2327                          *
2328                          * We zero the parent pointer *after* freeing its
2329                          * pointee in the bitmaps, so if extend_transaction()
2330                          * for some reason fails to put the bitmap changes and
2331                          * the release into the same transaction, recovery
2332                          * will merely complain about releasing a free block,
2333                          * rather than leaking blocks.
2334                          */
2335                         if (is_handle_aborted(handle))
2336                                 return;
2337                         if (try_to_extend_transaction(handle, inode)) {
2338                                 ext3_mark_inode_dirty(handle, inode);
2339                                 truncate_restart_transaction(handle, inode);
2340                         }
2341
2342                         /*
2343                          * We've probably journalled the indirect block several
2344                          * times during the truncate.  But it's no longer
2345                          * needed and we now drop it from the transaction via
2346                          * journal_revoke().
2347                          *
2348                          * That's easy if it's exclusively part of this
2349                          * transaction.  But if it's part of the committing
2350                          * transaction then journal_forget() will simply
2351                          * brelse() it.  That means that if the underlying
2352                          * block is reallocated in ext3_get_block(),
2353                          * unmap_underlying_metadata() will find this block
2354                          * and will try to get rid of it.  damn, damn. Thus
2355                          * we don't allow a block to be reallocated until
2356                          * a transaction freeing it has fully committed.
2357                          *
2358                          * We also have to make sure journal replay after a
2359                          * crash does not overwrite non-journaled data blocks
2360                          * with old metadata when the block got reallocated for
2361                          * data.  Thus we have to store a revoke record for a
2362                          * block in the same transaction in which we free the
2363                          * block.
2364                          */
2365                         ext3_forget(handle, 1, inode, bh, bh->b_blocknr);
2366
2367                         ext3_free_blocks(handle, inode, nr, 1);
2368
2369                         if (parent_bh) {
2370                                 /*
2371                                  * The block which we have just freed is
2372                                  * pointed to by an indirect block: journal it
2373                                  */
2374                                 BUFFER_TRACE(parent_bh, "get_write_access");
2375                                 if (!ext3_journal_get_write_access(handle,
2376                                                                    parent_bh)){
2377                                         *p = 0;
2378                                         BUFFER_TRACE(parent_bh,
2379                                         "call ext3_journal_dirty_metadata");
2380                                         ext3_journal_dirty_metadata(handle,
2381                                                                     parent_bh);
2382                                 }
2383                         }
2384                 }
2385         } else {
2386                 /* We have reached the bottom of the tree. */
2387                 BUFFER_TRACE(parent_bh, "free data blocks");
2388                 ext3_free_data(handle, inode, parent_bh, first, last);
2389         }
2390 }
2391
2392 int ext3_can_truncate(struct inode *inode)
2393 {
2394         if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
2395                 return 0;
2396         if (S_ISREG(inode->i_mode))
2397                 return 1;
2398         if (S_ISDIR(inode->i_mode))
2399                 return 1;
2400         if (S_ISLNK(inode->i_mode))
2401                 return !ext3_inode_is_fast_symlink(inode);
2402         return 0;
2403 }
2404
2405 /*
2406  * ext3_truncate()
2407  *
2408  * We block out ext3_get_block() block instantiations across the entire
2409  * transaction, and VFS/VM ensures that ext3_truncate() cannot run
2410  * simultaneously on behalf of the same inode.
2411  *
2412  * As we work through the truncate and commmit bits of it to the journal there
2413  * is one core, guiding principle: the file's tree must always be consistent on
2414  * disk.  We must be able to restart the truncate after a crash.
2415  *
2416  * The file's tree may be transiently inconsistent in memory (although it
2417  * probably isn't), but whenever we close off and commit a journal transaction,
2418  * the contents of (the filesystem + the journal) must be consistent and
2419  * restartable.  It's pretty simple, really: bottom up, right to left (although
2420  * left-to-right works OK too).
2421  *
2422  * Note that at recovery time, journal replay occurs *before* the restart of
2423  * truncate against the orphan inode list.
2424  *
2425  * The committed inode has the new, desired i_size (which is the same as
2426  * i_disksize in this case).  After a crash, ext3_orphan_cleanup() will see
2427  * that this inode's truncate did not complete and it will again call
2428  * ext3_truncate() to have another go.  So there will be instantiated blocks
2429  * to the right of the truncation point in a crashed ext3 filesystem.  But
2430  * that's fine - as long as they are linked from the inode, the post-crash
2431  * ext3_truncate() run will find them and release them.
2432  */
2433 void ext3_truncate(struct inode *inode)
2434 {
2435         handle_t *handle;
2436         struct ext3_inode_info *ei = EXT3_I(inode);
2437         __le32 *i_data = ei->i_data;
2438         int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
2439         struct address_space *mapping = inode->i_mapping;
2440         int offsets[4];
2441         Indirect chain[4];
2442         Indirect *partial;
2443         __le32 nr = 0;
2444         int n;
2445         long last_block;
2446         unsigned blocksize = inode->i_sb->s_blocksize;
2447         struct page *page;
2448
2449         if (!ext3_can_truncate(inode))
2450                 goto out_notrans;
2451
2452         if (inode->i_size == 0 && ext3_should_writeback_data(inode))
2453                 ext3_set_inode_state(inode, EXT3_STATE_FLUSH_ON_CLOSE);
2454
2455         /*
2456          * We have to lock the EOF page here, because lock_page() nests
2457          * outside journal_start().
2458          */
2459         if ((inode->i_size & (blocksize - 1)) == 0) {
2460                 /* Block boundary? Nothing to do */
2461                 page = NULL;
2462         } else {
2463                 page = grab_cache_page(mapping,
2464                                 inode->i_size >> PAGE_CACHE_SHIFT);
2465                 if (!page)
2466                         goto out_notrans;
2467         }
2468
2469         handle = start_transaction(inode);
2470         if (IS_ERR(handle)) {
2471                 if (page) {
2472                         clear_highpage(page);
2473                         flush_dcache_page(page);
2474                         unlock_page(page);
2475                         page_cache_release(page);
2476                 }
2477                 goto out_notrans;
2478         }
2479
2480         last_block = (inode->i_size + blocksize-1)
2481                                         >> EXT3_BLOCK_SIZE_BITS(inode->i_sb);
2482
2483         if (page)
2484                 ext3_block_truncate_page(handle, page, mapping, inode->i_size);
2485
2486         n = ext3_block_to_path(inode, last_block, offsets, NULL);
2487         if (n == 0)
2488                 goto out_stop;  /* error */
2489
2490         /*
2491          * OK.  This truncate is going to happen.  We add the inode to the
2492          * orphan list, so that if this truncate spans multiple transactions,
2493          * and we crash, we will resume the truncate when the filesystem
2494          * recovers.  It also marks the inode dirty, to catch the new size.
2495          *
2496          * Implication: the file must always be in a sane, consistent
2497          * truncatable state while each transaction commits.
2498          */
2499         if (ext3_orphan_add(handle, inode))
2500                 goto out_stop;
2501
2502         /*
2503          * The orphan list entry will now protect us from any crash which
2504          * occurs before the truncate completes, so it is now safe to propagate
2505          * the new, shorter inode size (held for now in i_size) into the
2506          * on-disk inode. We do this via i_disksize, which is the value which
2507          * ext3 *really* writes onto the disk inode.
2508          */
2509         ei->i_disksize = inode->i_size;
2510
2511         /*
2512          * From here we block out all ext3_get_block() callers who want to
2513          * modify the block allocation tree.
2514          */
2515         mutex_lock(&ei->truncate_mutex);
2516
2517         if (n == 1) {           /* direct blocks */
2518                 ext3_free_data(handle, inode, NULL, i_data+offsets[0],
2519                                i_data + EXT3_NDIR_BLOCKS);
2520                 goto do_indirects;
2521         }
2522
2523         partial = ext3_find_shared(inode, n, offsets, chain, &nr);
2524         /* Kill the top of shared branch (not detached) */
2525         if (nr) {
2526                 if (partial == chain) {
2527                         /* Shared branch grows from the inode */
2528                         ext3_free_branches(handle, inode, NULL,
2529                                            &nr, &nr+1, (chain+n-1) - partial);
2530                         *partial->p = 0;
2531                         /*
2532                          * We mark the inode dirty prior to restart,
2533                          * and prior to stop.  No need for it here.
2534                          */
2535                 } else {
2536                         /* Shared branch grows from an indirect block */
2537                         ext3_free_branches(handle, inode, partial->bh,
2538                                         partial->p,
2539                                         partial->p+1, (chain+n-1) - partial);
2540                 }
2541         }
2542         /* Clear the ends of indirect blocks on the shared branch */
2543         while (partial > chain) {
2544                 ext3_free_branches(handle, inode, partial->bh, partial->p + 1,
2545                                    (__le32*)partial->bh->b_data+addr_per_block,
2546                                    (chain+n-1) - partial);
2547                 BUFFER_TRACE(partial->bh, "call brelse");
2548                 brelse (partial->bh);
2549                 partial--;
2550         }
2551 do_indirects:
2552         /* Kill the remaining (whole) subtrees */
2553         switch (offsets[0]) {
2554         default:
2555                 nr = i_data[EXT3_IND_BLOCK];
2556                 if (nr) {
2557                         ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
2558                         i_data[EXT3_IND_BLOCK] = 0;
2559                 }
2560         case EXT3_IND_BLOCK:
2561                 nr = i_data[EXT3_DIND_BLOCK];
2562                 if (nr) {
2563                         ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
2564                         i_data[EXT3_DIND_BLOCK] = 0;
2565                 }
2566         case EXT3_DIND_BLOCK:
2567                 nr = i_data[EXT3_TIND_BLOCK];
2568                 if (nr) {
2569                         ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
2570                         i_data[EXT3_TIND_BLOCK] = 0;
2571                 }
2572         case EXT3_TIND_BLOCK:
2573                 ;
2574         }
2575
2576         ext3_discard_reservation(inode);
2577
2578         mutex_unlock(&ei->truncate_mutex);
2579         inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
2580         ext3_mark_inode_dirty(handle, inode);
2581
2582         /*
2583          * In a multi-transaction truncate, we only make the final transaction
2584          * synchronous
2585          */
2586         if (IS_SYNC(inode))
2587                 handle->h_sync = 1;
2588 out_stop:
2589         /*
2590          * If this was a simple ftruncate(), and the file will remain alive
2591          * then we need to clear up the orphan record which we created above.
2592          * However, if this was a real unlink then we were called by
2593          * ext3_evict_inode(), and we allow that function to clean up the
2594          * orphan info for us.
2595          */
2596         if (inode->i_nlink)
2597                 ext3_orphan_del(handle, inode);
2598
2599         ext3_journal_stop(handle);
2600         return;
2601 out_notrans:
2602         /*
2603          * Delete the inode from orphan list so that it doesn't stay there
2604          * forever and trigger assertion on umount.
2605          */
2606         if (inode->i_nlink)
2607                 ext3_orphan_del(NULL, inode);
2608 }
2609
2610 static ext3_fsblk_t ext3_get_inode_block(struct super_block *sb,
2611                 unsigned long ino, struct ext3_iloc *iloc)
2612 {
2613         unsigned long block_group;
2614         unsigned long offset;
2615         ext3_fsblk_t block;
2616         struct ext3_group_desc *gdp;
2617
2618         if (!ext3_valid_inum(sb, ino)) {
2619                 /*
2620                  * This error is already checked for in namei.c unless we are
2621                  * looking at an NFS filehandle, in which case no error
2622                  * report is needed
2623                  */
2624                 return 0;
2625         }
2626
2627         block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
2628         gdp = ext3_get_group_desc(sb, block_group, NULL);
2629         if (!gdp)
2630                 return 0;
2631         /*
2632          * Figure out the offset within the block group inode table
2633          */
2634         offset = ((ino - 1) % EXT3_INODES_PER_GROUP(sb)) *
2635                 EXT3_INODE_SIZE(sb);
2636         block = le32_to_cpu(gdp->bg_inode_table) +
2637                 (offset >> EXT3_BLOCK_SIZE_BITS(sb));
2638
2639         iloc->block_group = block_group;
2640         iloc->offset = offset & (EXT3_BLOCK_SIZE(sb) - 1);
2641         return block;
2642 }
2643
2644 /*
2645  * ext3_get_inode_loc returns with an extra refcount against the inode's
2646  * underlying buffer_head on success. If 'in_mem' is true, we have all
2647  * data in memory that is needed to recreate the on-disk version of this
2648  * inode.
2649  */
2650 static int __ext3_get_inode_loc(struct inode *inode,
2651                                 struct ext3_iloc *iloc, int in_mem)
2652 {
2653         ext3_fsblk_t block;
2654         struct buffer_head *bh;
2655
2656         block = ext3_get_inode_block(inode->i_sb, inode->i_ino, iloc);
2657         if (!block)
2658                 return -EIO;
2659
2660         bh = sb_getblk(inode->i_sb, block);
2661         if (!bh) {
2662                 ext3_error (inode->i_sb, "ext3_get_inode_loc",
2663                                 "unable to read inode block - "
2664                                 "inode=%lu, block="E3FSBLK,
2665                                  inode->i_ino, block);
2666                 return -EIO;
2667         }
2668         if (!buffer_uptodate(bh)) {
2669                 lock_buffer(bh);
2670
2671                 /*
2672                  * If the buffer has the write error flag, we have failed
2673                  * to write out another inode in the same block.  In this
2674                  * case, we don't have to read the block because we may
2675                  * read the old inode data successfully.
2676                  */
2677                 if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
2678                         set_buffer_uptodate(bh);
2679
2680                 if (buffer_uptodate(bh)) {
2681                         /* someone brought it uptodate while we waited */
2682                         unlock_buffer(bh);
2683                         goto has_buffer;
2684                 }
2685
2686                 /*
2687                  * If we have all information of the inode in memory and this
2688                  * is the only valid inode in the block, we need not read the
2689                  * block.
2690                  */
2691                 if (in_mem) {
2692                         struct buffer_head *bitmap_bh;
2693                         struct ext3_group_desc *desc;
2694                         int inodes_per_buffer;
2695                         int inode_offset, i;
2696                         int block_group;
2697                         int start;
2698
2699                         block_group = (inode->i_ino - 1) /
2700                                         EXT3_INODES_PER_GROUP(inode->i_sb);
2701                         inodes_per_buffer = bh->b_size /
2702                                 EXT3_INODE_SIZE(inode->i_sb);
2703                         inode_offset = ((inode->i_ino - 1) %
2704                                         EXT3_INODES_PER_GROUP(inode->i_sb));
2705                         start = inode_offset & ~(inodes_per_buffer - 1);
2706
2707                         /* Is the inode bitmap in cache? */
2708                         desc = ext3_get_group_desc(inode->i_sb,
2709                                                 block_group, NULL);
2710                         if (!desc)
2711                                 goto make_io;
2712
2713                         bitmap_bh = sb_getblk(inode->i_sb,
2714                                         le32_to_cpu(desc->bg_inode_bitmap));
2715                         if (!bitmap_bh)
2716                                 goto make_io;
2717
2718                         /*
2719                          * If the inode bitmap isn't in cache then the
2720                          * optimisation may end up performing two reads instead
2721                          * of one, so skip it.
2722                          */
2723                         if (!buffer_uptodate(bitmap_bh)) {
2724                                 brelse(bitmap_bh);
2725                                 goto make_io;
2726                         }
2727                         for (i = start; i < start + inodes_per_buffer; i++) {
2728                                 if (i == inode_offset)
2729                                         continue;
2730                                 if (ext3_test_bit(i, bitmap_bh->b_data))
2731                                         break;
2732                         }
2733                         brelse(bitmap_bh);
2734                         if (i == start + inodes_per_buffer) {
2735                                 /* all other inodes are free, so skip I/O */
2736                                 memset(bh->b_data, 0, bh->b_size);
2737                                 set_buffer_uptodate(bh);
2738                                 unlock_buffer(bh);
2739                                 goto has_buffer;
2740                         }
2741                 }
2742
2743 make_io:
2744                 /*
2745                  * There are other valid inodes in the buffer, this inode
2746                  * has in-inode xattrs, or we don't have this inode in memory.
2747                  * Read the block from disk.
2748                  */
2749                 get_bh(bh);
2750                 bh->b_end_io = end_buffer_read_sync;
2751                 submit_bh(READ_META, bh);
2752                 wait_on_buffer(bh);
2753                 if (!buffer_uptodate(bh)) {
2754                         ext3_error(inode->i_sb, "ext3_get_inode_loc",
2755                                         "unable to read inode block - "
2756                                         "inode=%lu, block="E3FSBLK,
2757                                         inode->i_ino, block);
2758                         brelse(bh);
2759                         return -EIO;
2760                 }
2761         }
2762 has_buffer:
2763         iloc->bh = bh;
2764         return 0;
2765 }
2766
2767 int ext3_get_inode_loc(struct inode *inode, struct ext3_iloc *iloc)
2768 {
2769         /* We have all inode data except xattrs in memory here. */
2770         return __ext3_get_inode_loc(inode, iloc,
2771                 !ext3_test_inode_state(inode, EXT3_STATE_XATTR));
2772 }
2773
2774 void ext3_set_inode_flags(struct inode *inode)
2775 {
2776         unsigned int flags = EXT3_I(inode)->i_flags;
2777
2778         inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
2779         if (flags & EXT3_SYNC_FL)
2780                 inode->i_flags |= S_SYNC;
2781         if (flags & EXT3_APPEND_FL)
2782                 inode->i_flags |= S_APPEND;
2783         if (flags & EXT3_IMMUTABLE_FL)
2784                 inode->i_flags |= S_IMMUTABLE;
2785         if (flags & EXT3_NOATIME_FL)
2786                 inode->i_flags |= S_NOATIME;
2787         if (flags & EXT3_DIRSYNC_FL)
2788                 inode->i_flags |= S_DIRSYNC;
2789 }
2790
2791 /* Propagate flags from i_flags to EXT3_I(inode)->i_flags */
2792 void ext3_get_inode_flags(struct ext3_inode_info *ei)
2793 {
2794         unsigned int flags = ei->vfs_inode.i_flags;
2795
2796         ei->i_flags &= ~(EXT3_SYNC_FL|EXT3_APPEND_FL|
2797                         EXT3_IMMUTABLE_FL|EXT3_NOATIME_FL|EXT3_DIRSYNC_FL);
2798         if (flags & S_SYNC)
2799                 ei->i_flags |= EXT3_SYNC_FL;
2800         if (flags & S_APPEND)
2801                 ei->i_flags |= EXT3_APPEND_FL;
2802         if (flags & S_IMMUTABLE)
2803                 ei->i_flags |= EXT3_IMMUTABLE_FL;
2804         if (flags & S_NOATIME)
2805                 ei->i_flags |= EXT3_NOATIME_FL;
2806         if (flags & S_DIRSYNC)
2807                 ei->i_flags |= EXT3_DIRSYNC_FL;
2808 }
2809
2810 struct inode *ext3_iget(struct super_block *sb, unsigned long ino)
2811 {
2812         struct ext3_iloc iloc;
2813         struct ext3_inode *raw_inode;
2814         struct ext3_inode_info *ei;
2815         struct buffer_head *bh;
2816         struct inode *inode;
2817         journal_t *journal = EXT3_SB(sb)->s_journal;
2818         transaction_t *transaction;
2819         long ret;
2820         int block;
2821
2822         inode = iget_locked(sb, ino);
2823         if (!inode)
2824                 return ERR_PTR(-ENOMEM);
2825         if (!(inode->i_state & I_NEW))
2826                 return inode;
2827
2828         ei = EXT3_I(inode);
2829         ei->i_block_alloc_info = NULL;
2830
2831         ret = __ext3_get_inode_loc(inode, &iloc, 0);
2832         if (ret < 0)
2833                 goto bad_inode;
2834         bh = iloc.bh;
2835         raw_inode = ext3_raw_inode(&iloc);
2836         inode->i_mode = le16_to_cpu(raw_inode->i_mode);
2837         inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
2838         inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
2839         if(!(test_opt (inode->i_sb, NO_UID32))) {
2840                 inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
2841                 inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
2842         }
2843         inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
2844         inode->i_size = le32_to_cpu(raw_inode->i_size);
2845         inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
2846         inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
2847         inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
2848         inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = inode->i_mtime.tv_nsec = 0;
2849
2850         ei->i_state_flags = 0;
2851         ei->i_dir_start_lookup = 0;
2852         ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
2853         /* We now have enough fields to check if the inode was active or not.
2854          * This is needed because nfsd might try to access dead inodes
2855          * the test is that same one that e2fsck uses
2856          * NeilBrown 1999oct15
2857          */
2858         if (inode->i_nlink == 0) {
2859                 if (inode->i_mode == 0 ||
2860                     !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ORPHAN_FS)) {
2861                         /* this inode is deleted */
2862                         brelse (bh);
2863                         ret = -ESTALE;
2864                         goto bad_inode;
2865                 }
2866                 /* The only unlinked inodes we let through here have
2867                  * valid i_mode and are being read by the orphan
2868                  * recovery code: that's fine, we're about to complete
2869                  * the process of deleting those. */
2870         }
2871         inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
2872         ei->i_flags = le32_to_cpu(raw_inode->i_flags);
2873 #ifdef EXT3_FRAGMENTS
2874         ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
2875         ei->i_frag_no = raw_inode->i_frag;
2876         ei->i_frag_size = raw_inode->i_fsize;
2877 #endif
2878         ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
2879         if (!S_ISREG(inode->i_mode)) {
2880                 ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
2881         } else {
2882                 inode->i_size |=
2883                         ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
2884         }
2885         ei->i_disksize = inode->i_size;
2886         inode->i_generation = le32_to_cpu(raw_inode->i_generation);
2887         ei->i_block_group = iloc.block_group;
2888         /*
2889          * NOTE! The in-memory inode i_data array is in little-endian order
2890          * even on big-endian machines: we do NOT byteswap the block numbers!
2891          */
2892         for (block = 0; block < EXT3_N_BLOCKS; block++)
2893                 ei->i_data[block] = raw_inode->i_block[block];
2894         INIT_LIST_HEAD(&ei->i_orphan);
2895
2896         /*
2897          * Set transaction id's of transactions that have to be committed
2898          * to finish f[data]sync. We set them to currently running transaction
2899          * as we cannot be sure that the inode or some of its metadata isn't
2900          * part of the transaction - the inode could have been reclaimed and
2901          * now it is reread from disk.
2902          */
2903         if (journal) {
2904                 tid_t tid;
2905
2906                 spin_lock(&journal->j_state_lock);
2907                 if (journal->j_running_transaction)
2908                         transaction = journal->j_running_transaction;
2909                 else
2910                         transaction = journal->j_committing_transaction;
2911                 if (transaction)
2912                         tid = transaction->t_tid;
2913                 else
2914                         tid = journal->j_commit_sequence;
2915                 spin_unlock(&journal->j_state_lock);
2916                 atomic_set(&ei->i_sync_tid, tid);
2917                 atomic_set(&ei->i_datasync_tid, tid);
2918         }
2919
2920         if (inode->i_ino >= EXT3_FIRST_INO(inode->i_sb) + 1 &&
2921             EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) {
2922                 /*
2923                  * When mke2fs creates big inodes it does not zero out
2924                  * the unused bytes above EXT3_GOOD_OLD_INODE_SIZE,
2925                  * so ignore those first few inodes.
2926                  */
2927                 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
2928                 if (EXT3_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
2929                     EXT3_INODE_SIZE(inode->i_sb)) {
2930                         brelse (bh);
2931                         ret = -EIO;
2932                         goto bad_inode;
2933                 }
2934                 if (ei->i_extra_isize == 0) {
2935                         /* The extra space is currently unused. Use it. */
2936                         ei->i_extra_isize = sizeof(struct ext3_inode) -
2937                                             EXT3_GOOD_OLD_INODE_SIZE;
2938                 } else {
2939                         __le32 *magic = (void *)raw_inode +
2940                                         EXT3_GOOD_OLD_INODE_SIZE +
2941                                         ei->i_extra_isize;
2942                         if (*magic == cpu_to_le32(EXT3_XATTR_MAGIC))
2943                                  ext3_set_inode_state(inode, EXT3_STATE_XATTR);
2944                 }
2945         } else
2946                 ei->i_extra_isize = 0;
2947
2948         if (S_ISREG(inode->i_mode)) {
2949                 inode->i_op = &ext3_file_inode_operations;
2950                 inode->i_fop = &ext3_file_operations;
2951                 ext3_set_aops(inode);
2952         } else if (S_ISDIR(inode->i_mode)) {
2953                 inode->i_op = &ext3_dir_inode_operations;
2954                 inode->i_fop = &ext3_dir_operations;
2955         } else if (S_ISLNK(inode->i_mode)) {
2956                 if (ext3_inode_is_fast_symlink(inode)) {
2957                         inode->i_op = &ext3_fast_symlink_inode_operations;
2958                         nd_terminate_link(ei->i_data, inode->i_size,
2959                                 sizeof(ei->i_data) - 1);
2960                 } else {
2961                         inode->i_op = &ext3_symlink_inode_operations;
2962                         ext3_set_aops(inode);
2963                 }
2964         } else {
2965                 inode->i_op = &ext3_special_inode_operations;
2966                 if (raw_inode->i_block[0])
2967                         init_special_inode(inode, inode->i_mode,
2968                            old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
2969                 else
2970                         init_special_inode(inode, inode->i_mode,
2971                            new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
2972         }
2973         brelse (iloc.bh);
2974         ext3_set_inode_flags(inode);
2975         unlock_new_inode(inode);
2976         return inode;
2977
2978 bad_inode:
2979         iget_failed(inode);
2980         return ERR_PTR(ret);
2981 }
2982
2983 /*
2984  * Post the struct inode info into an on-disk inode location in the
2985  * buffer-cache.  This gobbles the caller's reference to the
2986  * buffer_head in the inode location struct.
2987  *
2988  * The caller must have write access to iloc->bh.
2989  */
2990 static int ext3_do_update_inode(handle_t *handle,
2991                                 struct inode *inode,
2992                                 struct ext3_iloc *iloc)
2993 {
2994         struct ext3_inode *raw_inode = ext3_raw_inode(iloc);
2995         struct ext3_inode_info *ei = EXT3_I(inode);
2996         struct buffer_head *bh = iloc->bh;
2997         int err = 0, rc, block;
2998
2999 again:
3000         /* we can't allow multiple procs in here at once, its a bit racey */
3001         lock_buffer(bh);
3002
3003         /* For fields not not tracking in the in-memory inode,
3004          * initialise them to zero for new inodes. */
3005         if (ext3_test_inode_state(inode, EXT3_STATE_NEW))
3006                 memset(raw_inode, 0, EXT3_SB(inode->i_sb)->s_inode_size);
3007
3008         ext3_get_inode_flags(ei);
3009         raw_inode->i_mode = cpu_to_le16(inode->i_mode);
3010         if(!(test_opt(inode->i_sb, NO_UID32))) {
3011                 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
3012                 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid));
3013 /*
3014  * Fix up interoperability with old kernels. Otherwise, old inodes get
3015  * re-used with the upper 16 bits of the uid/gid intact
3016  */
3017                 if(!ei->i_dtime) {
3018                         raw_inode->i_uid_high =
3019                                 cpu_to_le16(high_16_bits(inode->i_uid));
3020                         raw_inode->i_gid_high =
3021                                 cpu_to_le16(high_16_bits(inode->i_gid));
3022                 } else {
3023                         raw_inode->i_uid_high = 0;
3024                         raw_inode->i_gid_high = 0;
3025                 }
3026         } else {
3027                 raw_inode->i_uid_low =
3028                         cpu_to_le16(fs_high2lowuid(inode->i_uid));
3029                 raw_inode->i_gid_low =
3030                         cpu_to_le16(fs_high2lowgid(inode->i_gid));
3031                 raw_inode->i_uid_high = 0;
3032                 raw_inode->i_gid_high = 0;
3033         }
3034         raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
3035         raw_inode->i_size = cpu_to_le32(ei->i_disksize);
3036         raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
3037         raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
3038         raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
3039         raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
3040         raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
3041         raw_inode->i_flags = cpu_to_le32(ei->i_flags);
3042 #ifdef EXT3_FRAGMENTS
3043         raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
3044         raw_inode->i_frag = ei->i_frag_no;
3045         raw_inode->i_fsize = ei->i_frag_size;
3046 #endif
3047         raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
3048         if (!S_ISREG(inode->i_mode)) {
3049                 raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
3050         } else {
3051                 raw_inode->i_size_high =
3052                         cpu_to_le32(ei->i_disksize >> 32);
3053                 if (ei->i_disksize > 0x7fffffffULL) {
3054                         struct super_block *sb = inode->i_sb;
3055                         if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
3056                                         EXT3_FEATURE_RO_COMPAT_LARGE_FILE) ||
3057                             EXT3_SB(sb)->s_es->s_rev_level ==
3058                                         cpu_to_le32(EXT3_GOOD_OLD_REV)) {
3059                                /* If this is the first large file
3060                                 * created, add a flag to the superblock.
3061                                 */
3062                                 unlock_buffer(bh);
3063                                 err = ext3_journal_get_write_access(handle,
3064                                                 EXT3_SB(sb)->s_sbh);
3065                                 if (err)
3066                                         goto out_brelse;
3067
3068                                 ext3_update_dynamic_rev(sb);
3069                                 EXT3_SET_RO_COMPAT_FEATURE(sb,
3070                                         EXT3_FEATURE_RO_COMPAT_LARGE_FILE);
3071                                 handle->h_sync = 1;
3072                                 err = ext3_journal_dirty_metadata(handle,
3073                                                 EXT3_SB(sb)->s_sbh);
3074                                 /* get our lock and start over */
3075                                 goto again;
3076                         }
3077                 }
3078         }
3079         raw_inode->i_generation = cpu_to_le32(inode->i_generation);
3080         if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
3081                 if (old_valid_dev(inode->i_rdev)) {
3082                         raw_inode->i_block[0] =
3083                                 cpu_to_le32(old_encode_dev(inode->i_rdev));
3084                         raw_inode->i_block[1] = 0;
3085                 } else {
3086                         raw_inode->i_block[0] = 0;
3087                         raw_inode->i_block[1] =
3088                                 cpu_to_le32(new_encode_dev(inode->i_rdev));
3089                         raw_inode->i_block[2] = 0;
3090                 }
3091         } else for (block = 0; block < EXT3_N_BLOCKS; block++)
3092                 raw_inode->i_block[block] = ei->i_data[block];
3093
3094         if (ei->i_extra_isize)
3095                 raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
3096
3097         BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
3098         unlock_buffer(bh);
3099         rc = ext3_journal_dirty_metadata(handle, bh);
3100         if (!err)
3101                 err = rc;
3102         ext3_clear_inode_state(inode, EXT3_STATE_NEW);
3103
3104         atomic_set(&ei->i_sync_tid, handle->h_transaction->t_tid);
3105 out_brelse:
3106         brelse (bh);
3107         ext3_std_error(inode->i_sb, err);
3108         return err;
3109 }
3110
3111 /*
3112  * ext3_write_inode()
3113  *
3114  * We are called from a few places:
3115  *
3116  * - Within generic_file_write() for O_SYNC files.
3117  *   Here, there will be no transaction running. We wait for any running
3118  *   trasnaction to commit.
3119  *
3120  * - Within sys_sync(), kupdate and such.
3121  *   We wait on commit, if tol to.
3122  *
3123  * - Within prune_icache() (PF_MEMALLOC == true)
3124  *   Here we simply return.  We can't afford to block kswapd on the
3125  *   journal commit.
3126  *
3127  * In all cases it is actually safe for us to return without doing anything,
3128  * because the inode has been copied into a raw inode buffer in
3129  * ext3_mark_inode_dirty().  This is a correctness thing for O_SYNC and for
3130  * knfsd.
3131  *
3132  * Note that we are absolutely dependent upon all inode dirtiers doing the
3133  * right thing: they *must* call mark_inode_dirty() after dirtying info in
3134  * which we are interested.
3135  *
3136  * It would be a bug for them to not do this.  The code:
3137  *
3138  *      mark_inode_dirty(inode)
3139  *      stuff();
3140  *      inode->i_size = expr;
3141  *
3142  * is in error because a kswapd-driven write_inode() could occur while
3143  * `stuff()' is running, and the new i_size will be lost.  Plus the inode
3144  * will no longer be on the superblock's dirty inode list.
3145  */
3146 int ext3_write_inode(struct inode *inode, struct writeback_control *wbc)
3147 {
3148         if (current->flags & PF_MEMALLOC)
3149                 return 0;
3150
3151         if (ext3_journal_current_handle()) {
3152                 jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
3153                 dump_stack();
3154                 return -EIO;
3155         }
3156
3157         if (wbc->sync_mode != WB_SYNC_ALL)
3158                 return 0;
3159
3160         return ext3_force_commit(inode->i_sb);
3161 }
3162
3163 /*
3164  * ext3_setattr()
3165  *
3166  * Called from notify_change.
3167  *
3168  * We want to trap VFS attempts to truncate the file as soon as
3169  * possible.  In particular, we want to make sure that when the VFS
3170  * shrinks i_size, we put the inode on the orphan list and modify
3171  * i_disksize immediately, so that during the subsequent flushing of
3172  * dirty pages and freeing of disk blocks, we can guarantee that any
3173  * commit will leave the blocks being flushed in an unused state on
3174  * disk.  (On recovery, the inode will get truncated and the blocks will
3175  * be freed, so we have a strong guarantee that no future commit will
3176  * leave these blocks visible to the user.)
3177  *
3178  * Called with inode->sem down.
3179  */
3180 int ext3_setattr(struct dentry *dentry, struct iattr *attr)
3181 {
3182         struct inode *inode = dentry->d_inode;
3183         int error, rc = 0;
3184         const unsigned int ia_valid = attr->ia_valid;
3185
3186         error = inode_change_ok(inode, attr);
3187         if (error)
3188                 return error;
3189
3190         if (is_quota_modification(inode, attr))
3191                 dquot_initialize(inode);
3192         if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
3193                 (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) {
3194                 handle_t *handle;
3195
3196                 /* (user+group)*(old+new) structure, inode write (sb,
3197                  * inode block, ? - but truncate inode update has it) */
3198                 handle = ext3_journal_start(inode, EXT3_MAXQUOTAS_INIT_BLOCKS(inode->i_sb)+
3199                                         EXT3_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)+3);
3200                 if (IS_ERR(handle)) {
3201                         error = PTR_ERR(handle);
3202                         goto err_out;
3203                 }
3204                 error = dquot_transfer(inode, attr);
3205                 if (error) {
3206                         ext3_journal_stop(handle);
3207                         return error;
3208                 }
3209                 /* Update corresponding info in inode so that everything is in
3210                  * one transaction */
3211                 if (attr->ia_valid & ATTR_UID)
3212                         inode->i_uid = attr->ia_uid;
3213                 if (attr->ia_valid & ATTR_GID)
3214                         inode->i_gid = attr->ia_gid;
3215                 error = ext3_mark_inode_dirty(handle, inode);
3216                 ext3_journal_stop(handle);
3217         }
3218
3219         if (S_ISREG(inode->i_mode) &&
3220             attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
3221                 handle_t *handle;
3222
3223                 handle = ext3_journal_start(inode, 3);
3224                 if (IS_ERR(handle)) {
3225                         error = PTR_ERR(handle);
3226                         goto err_out;
3227                 }
3228
3229                 error = ext3_orphan_add(handle, inode);
3230                 EXT3_I(inode)->i_disksize = attr->ia_size;
3231                 rc = ext3_mark_inode_dirty(handle, inode);
3232                 if (!error)
3233                         error = rc;
3234                 ext3_journal_stop(handle);
3235         }
3236
3237         if ((attr->ia_valid & ATTR_SIZE) &&
3238             attr->ia_size != i_size_read(inode)) {
3239                 rc = vmtruncate(inode, attr->ia_size);
3240                 if (rc)
3241                         goto err_out;
3242         }
3243
3244         setattr_copy(inode, attr);
3245         mark_inode_dirty(inode);
3246
3247         if (ia_valid & ATTR_MODE)
3248                 rc = ext3_acl_chmod(inode);
3249
3250 err_out:
3251         ext3_std_error(inode->i_sb, error);
3252         if (!error)
3253                 error = rc;
3254         return error;
3255 }
3256
3257
3258 /*
3259  * How many blocks doth make a writepage()?
3260  *
3261  * With N blocks per page, it may be:
3262  * N data blocks
3263  * 2 indirect block
3264  * 2 dindirect
3265  * 1 tindirect
3266  * N+5 bitmap blocks (from the above)
3267  * N+5 group descriptor summary blocks
3268  * 1 inode block
3269  * 1 superblock.
3270  * 2 * EXT3_SINGLEDATA_TRANS_BLOCKS for the quote files
3271  *
3272  * 3 * (N + 5) + 2 + 2 * EXT3_SINGLEDATA_TRANS_BLOCKS
3273  *
3274  * With ordered or writeback data it's the same, less the N data blocks.
3275  *
3276  * If the inode's direct blocks can hold an integral number of pages then a
3277  * page cannot straddle two indirect blocks, and we can only touch one indirect
3278  * and dindirect block, and the "5" above becomes "3".
3279  *
3280  * This still overestimates under most circumstances.  If we were to pass the
3281  * start and end offsets in here as well we could do block_to_path() on each
3282  * block and work out the exact number of indirects which are touched.  Pah.
3283  */
3284
3285 static int ext3_writepage_trans_blocks(struct inode *inode)
3286 {
3287         int bpp = ext3_journal_blocks_per_page(inode);
3288         int indirects = (EXT3_NDIR_BLOCKS % bpp) ? 5 : 3;
3289         int ret;
3290
3291         if (ext3_should_journal_data(inode))
3292                 ret = 3 * (bpp + indirects) + 2;
3293         else
3294                 ret = 2 * (bpp + indirects) + indirects + 2;
3295
3296 #ifdef CONFIG_QUOTA
3297         /* We know that structure was already allocated during dquot_initialize so
3298          * we will be updating only the data blocks + inodes */
3299         ret += EXT3_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
3300 #endif
3301
3302         return ret;
3303 }
3304
3305 /*
3306  * The caller must have previously called ext3_reserve_inode_write().
3307  * Give this, we know that the caller already has write access to iloc->bh.
3308  */
3309 int ext3_mark_iloc_dirty(handle_t *handle,
3310                 struct inode *inode, struct ext3_iloc *iloc)
3311 {
3312         int err = 0;
3313
3314         /* the do_update_inode consumes one bh->b_count */
3315         get_bh(iloc->bh);
3316
3317         /* ext3_do_update_inode() does journal_dirty_metadata */
3318         err = ext3_do_update_inode(handle, inode, iloc);
3319         put_bh(iloc->bh);
3320         return err;
3321 }
3322
3323 /*
3324  * On success, We end up with an outstanding reference count against
3325  * iloc->bh.  This _must_ be cleaned up later.
3326  */
3327
3328 int
3329 ext3_reserve_inode_write(handle_t *handle, struct inode *inode,
3330                          struct ext3_iloc *iloc)
3331 {
3332         int err = 0;
3333         if (handle) {
3334                 err = ext3_get_inode_loc(inode, iloc);
3335                 if (!err) {
3336                         BUFFER_TRACE(iloc->bh, "get_write_access");
3337                         err = ext3_journal_get_write_access(handle, iloc->bh);
3338                         if (err) {
3339                                 brelse(iloc->bh);
3340                                 iloc->bh = NULL;
3341                         }
3342                 }
3343         }
3344         ext3_std_error(inode->i_sb, err);
3345         return err;
3346 }
3347
3348 /*
3349  * What we do here is to mark the in-core inode as clean with respect to inode
3350  * dirtiness (it may still be data-dirty).
3351  * This means that the in-core inode may be reaped by prune_icache
3352  * without having to perform any I/O.  This is a very good thing,
3353  * because *any* task may call prune_icache - even ones which
3354  * have a transaction open against a different journal.
3355  *
3356  * Is this cheating?  Not really.  Sure, we haven't written the
3357  * inode out, but prune_icache isn't a user-visible syncing function.
3358  * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
3359  * we start and wait on commits.
3360  *
3361  * Is this efficient/effective?  Well, we're being nice to the system
3362  * by cleaning up our inodes proactively so they can be reaped
3363  * without I/O.  But we are potentially leaving up to five seconds'
3364  * worth of inodes floating about which prune_icache wants us to
3365  * write out.  One way to fix that would be to get prune_icache()
3366  * to do a write_super() to free up some memory.  It has the desired
3367  * effect.
3368  */
3369 int ext3_mark_inode_dirty(handle_t *handle, struct inode *inode)
3370 {
3371         struct ext3_iloc iloc;
3372         int err;
3373
3374         might_sleep();
3375         err = ext3_reserve_inode_write(handle, inode, &iloc);
3376         if (!err)
3377                 err = ext3_mark_iloc_dirty(handle, inode, &iloc);
3378         return err;
3379 }
3380
3381 /*
3382  * ext3_dirty_inode() is called from __mark_inode_dirty()
3383  *
3384  * We're really interested in the case where a file is being extended.
3385  * i_size has been changed by generic_commit_write() and we thus need
3386  * to include the updated inode in the current transaction.
3387  *
3388  * Also, dquot_alloc_space() will always dirty the inode when blocks
3389  * are allocated to the file.
3390  *
3391  * If the inode is marked synchronous, we don't honour that here - doing
3392  * so would cause a commit on atime updates, which we don't bother doing.
3393  * We handle synchronous inodes at the highest possible level.
3394  */
3395 void ext3_dirty_inode(struct inode *inode, int flags)
3396 {
3397         handle_t *current_handle = ext3_journal_current_handle();
3398         handle_t *handle;
3399
3400         handle = ext3_journal_start(inode, 2);
3401         if (IS_ERR(handle))
3402                 goto out;
3403         if (current_handle &&
3404                 current_handle->h_transaction != handle->h_transaction) {
3405                 /* This task has a transaction open against a different fs */
3406                 printk(KERN_EMERG "%s: transactions do not match!\n",
3407                        __func__);
3408         } else {
3409                 jbd_debug(5, "marking dirty.  outer handle=%p\n",
3410                                 current_handle);
3411                 ext3_mark_inode_dirty(handle, inode);
3412         }
3413         ext3_journal_stop(handle);
3414 out:
3415         return;
3416 }
3417
3418 #if 0
3419 /*
3420  * Bind an inode's backing buffer_head into this transaction, to prevent
3421  * it from being flushed to disk early.  Unlike
3422  * ext3_reserve_inode_write, this leaves behind no bh reference and
3423  * returns no iloc structure, so the caller needs to repeat the iloc
3424  * lookup to mark the inode dirty later.
3425  */
3426 static int ext3_pin_inode(handle_t *handle, struct inode *inode)
3427 {
3428         struct ext3_iloc iloc;
3429
3430         int err = 0;
3431         if (handle) {
3432                 err = ext3_get_inode_loc(inode, &iloc);
3433                 if (!err) {
3434                         BUFFER_TRACE(iloc.bh, "get_write_access");
3435                         err = journal_get_write_access(handle, iloc.bh);
3436                         if (!err)
3437                                 err = ext3_journal_dirty_metadata(handle,
3438                                                                   iloc.bh);
3439                         brelse(iloc.bh);
3440                 }
3441         }
3442         ext3_std_error(inode->i_sb, err);
3443         return err;
3444 }
3445 #endif
3446
3447 int ext3_change_inode_journal_flag(struct inode *inode, int val)
3448 {
3449         journal_t *journal;
3450         handle_t *handle;
3451         int err;
3452
3453         /*
3454          * We have to be very careful here: changing a data block's
3455          * journaling status dynamically is dangerous.  If we write a
3456          * data block to the journal, change the status and then delete
3457          * that block, we risk forgetting to revoke the old log record
3458          * from the journal and so a subsequent replay can corrupt data.
3459          * So, first we make sure that the journal is empty and that
3460          * nobody is changing anything.
3461          */
3462
3463         journal = EXT3_JOURNAL(inode);
3464         if (is_journal_aborted(journal))
3465                 return -EROFS;
3466
3467         journal_lock_updates(journal);
3468         journal_flush(journal);
3469
3470         /*
3471          * OK, there are no updates running now, and all cached data is
3472          * synced to disk.  We are now in a completely consistent state
3473          * which doesn't have anything in the journal, and we know that
3474          * no filesystem updates are running, so it is safe to modify
3475          * the inode's in-core data-journaling state flag now.
3476          */
3477
3478         if (val)
3479                 EXT3_I(inode)->i_flags |= EXT3_JOURNAL_DATA_FL;
3480         else
3481                 EXT3_I(inode)->i_flags &= ~EXT3_JOURNAL_DATA_FL;
3482         ext3_set_aops(inode);
3483
3484         journal_unlock_updates(journal);
3485
3486         /* Finally we can mark the inode as dirty. */
3487
3488         handle = ext3_journal_start(inode, 1);
3489         if (IS_ERR(handle))
3490                 return PTR_ERR(handle);
3491
3492         err = ext3_mark_inode_dirty(handle, inode);
3493         handle->h_sync = 1;
3494         ext3_journal_stop(handle);
3495         ext3_std_error(inode->i_sb, err);
3496
3497         return err;
3498 }