ext3: don't read inode block if the buffer has a write error
[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 "xattr.h"
40 #include "acl.h"
41
42 static int ext3_writepage_trans_blocks(struct inode *inode);
43
44 /*
45  * Test whether an inode is a fast symlink.
46  */
47 static int ext3_inode_is_fast_symlink(struct inode *inode)
48 {
49         int ea_blocks = EXT3_I(inode)->i_file_acl ?
50                 (inode->i_sb->s_blocksize >> 9) : 0;
51
52         return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
53 }
54
55 /*
56  * The ext3 forget function must perform a revoke if we are freeing data
57  * which has been journaled.  Metadata (eg. indirect blocks) must be
58  * revoked in all cases.
59  *
60  * "bh" may be NULL: a metadata block may have been freed from memory
61  * but there may still be a record of it in the journal, and that record
62  * still needs to be revoked.
63  */
64 int ext3_forget(handle_t *handle, int is_metadata, struct inode *inode,
65                         struct buffer_head *bh, ext3_fsblk_t blocknr)
66 {
67         int err;
68
69         might_sleep();
70
71         BUFFER_TRACE(bh, "enter");
72
73         jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
74                   "data mode %lx\n",
75                   bh, is_metadata, inode->i_mode,
76                   test_opt(inode->i_sb, DATA_FLAGS));
77
78         /* Never use the revoke function if we are doing full data
79          * journaling: there is no need to, and a V1 superblock won't
80          * support it.  Otherwise, only skip the revoke on un-journaled
81          * data blocks. */
82
83         if (test_opt(inode->i_sb, DATA_FLAGS) == EXT3_MOUNT_JOURNAL_DATA ||
84             (!is_metadata && !ext3_should_journal_data(inode))) {
85                 if (bh) {
86                         BUFFER_TRACE(bh, "call journal_forget");
87                         return ext3_journal_forget(handle, bh);
88                 }
89                 return 0;
90         }
91
92         /*
93          * data!=journal && (is_metadata || should_journal_data(inode))
94          */
95         BUFFER_TRACE(bh, "call ext3_journal_revoke");
96         err = ext3_journal_revoke(handle, blocknr, bh);
97         if (err)
98                 ext3_abort(inode->i_sb, __func__,
99                            "error %d when attempting revoke", err);
100         BUFFER_TRACE(bh, "exit");
101         return err;
102 }
103
104 /*
105  * Work out how many blocks we need to proceed with the next chunk of a
106  * truncate transaction.
107  */
108 static unsigned long blocks_for_truncate(struct inode *inode)
109 {
110         unsigned long needed;
111
112         needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
113
114         /* Give ourselves just enough room to cope with inodes in which
115          * i_blocks is corrupt: we've seen disk corruptions in the past
116          * which resulted in random data in an inode which looked enough
117          * like a regular file for ext3 to try to delete it.  Things
118          * will go a bit crazy if that happens, but at least we should
119          * try not to panic the whole kernel. */
120         if (needed < 2)
121                 needed = 2;
122
123         /* But we need to bound the transaction so we don't overflow the
124          * journal. */
125         if (needed > EXT3_MAX_TRANS_DATA)
126                 needed = EXT3_MAX_TRANS_DATA;
127
128         return EXT3_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
129 }
130
131 /*
132  * Truncate transactions can be complex and absolutely huge.  So we need to
133  * be able to restart the transaction at a conventient checkpoint to make
134  * sure we don't overflow the journal.
135  *
136  * start_transaction gets us a new handle for a truncate transaction,
137  * and extend_transaction tries to extend the existing one a bit.  If
138  * extend fails, we need to propagate the failure up and restart the
139  * transaction in the top-level truncate loop. --sct
140  */
141 static handle_t *start_transaction(struct inode *inode)
142 {
143         handle_t *result;
144
145         result = ext3_journal_start(inode, blocks_for_truncate(inode));
146         if (!IS_ERR(result))
147                 return result;
148
149         ext3_std_error(inode->i_sb, PTR_ERR(result));
150         return result;
151 }
152
153 /*
154  * Try to extend this transaction for the purposes of truncation.
155  *
156  * Returns 0 if we managed to create more room.  If we can't create more
157  * room, and the transaction must be restarted we return 1.
158  */
159 static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
160 {
161         if (handle->h_buffer_credits > EXT3_RESERVE_TRANS_BLOCKS)
162                 return 0;
163         if (!ext3_journal_extend(handle, blocks_for_truncate(inode)))
164                 return 0;
165         return 1;
166 }
167
168 /*
169  * Restart the transaction associated with *handle.  This does a commit,
170  * so before we call here everything must be consistently dirtied against
171  * this transaction.
172  */
173 static int ext3_journal_test_restart(handle_t *handle, struct inode *inode)
174 {
175         jbd_debug(2, "restarting handle %p\n", handle);
176         return ext3_journal_restart(handle, blocks_for_truncate(inode));
177 }
178
179 /*
180  * Called at the last iput() if i_nlink is zero.
181  */
182 void ext3_delete_inode (struct inode * inode)
183 {
184         handle_t *handle;
185
186         truncate_inode_pages(&inode->i_data, 0);
187
188         if (is_bad_inode(inode))
189                 goto no_delete;
190
191         handle = start_transaction(inode);
192         if (IS_ERR(handle)) {
193                 /*
194                  * If we're going to skip the normal cleanup, we still need to
195                  * make sure that the in-core orphan linked list is properly
196                  * cleaned up.
197                  */
198                 ext3_orphan_del(NULL, inode);
199                 goto no_delete;
200         }
201
202         if (IS_SYNC(inode))
203                 handle->h_sync = 1;
204         inode->i_size = 0;
205         if (inode->i_blocks)
206                 ext3_truncate(inode);
207         /*
208          * Kill off the orphan record which ext3_truncate created.
209          * AKPM: I think this can be inside the above `if'.
210          * Note that ext3_orphan_del() has to be able to cope with the
211          * deletion of a non-existent orphan - this is because we don't
212          * know if ext3_truncate() actually created an orphan record.
213          * (Well, we could do this if we need to, but heck - it works)
214          */
215         ext3_orphan_del(handle, inode);
216         EXT3_I(inode)->i_dtime  = get_seconds();
217
218         /*
219          * One subtle ordering requirement: if anything has gone wrong
220          * (transaction abort, IO errors, whatever), then we can still
221          * do these next steps (the fs will already have been marked as
222          * having errors), but we can't free the inode if the mark_dirty
223          * fails.
224          */
225         if (ext3_mark_inode_dirty(handle, inode))
226                 /* If that failed, just do the required in-core inode clear. */
227                 clear_inode(inode);
228         else
229                 ext3_free_inode(handle, inode);
230         ext3_journal_stop(handle);
231         return;
232 no_delete:
233         clear_inode(inode);     /* We must guarantee clearing of inode... */
234 }
235
236 typedef struct {
237         __le32  *p;
238         __le32  key;
239         struct buffer_head *bh;
240 } Indirect;
241
242 static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
243 {
244         p->key = *(p->p = v);
245         p->bh = bh;
246 }
247
248 static int verify_chain(Indirect *from, Indirect *to)
249 {
250         while (from <= to && from->key == *from->p)
251                 from++;
252         return (from > to);
253 }
254
255 /**
256  *      ext3_block_to_path - parse the block number into array of offsets
257  *      @inode: inode in question (we are only interested in its superblock)
258  *      @i_block: block number to be parsed
259  *      @offsets: array to store the offsets in
260  *      @boundary: set this non-zero if the referred-to block is likely to be
261  *             followed (on disk) by an indirect block.
262  *
263  *      To store the locations of file's data ext3 uses a data structure common
264  *      for UNIX filesystems - tree of pointers anchored in the inode, with
265  *      data blocks at leaves and indirect blocks in intermediate nodes.
266  *      This function translates the block number into path in that tree -
267  *      return value is the path length and @offsets[n] is the offset of
268  *      pointer to (n+1)th node in the nth one. If @block is out of range
269  *      (negative or too large) warning is printed and zero returned.
270  *
271  *      Note: function doesn't find node addresses, so no IO is needed. All
272  *      we need to know is the capacity of indirect blocks (taken from the
273  *      inode->i_sb).
274  */
275
276 /*
277  * Portability note: the last comparison (check that we fit into triple
278  * indirect block) is spelled differently, because otherwise on an
279  * architecture with 32-bit longs and 8Kb pages we might get into trouble
280  * if our filesystem had 8Kb blocks. We might use long long, but that would
281  * kill us on x86. Oh, well, at least the sign propagation does not matter -
282  * i_block would have to be negative in the very beginning, so we would not
283  * get there at all.
284  */
285
286 static int ext3_block_to_path(struct inode *inode,
287                         long i_block, int offsets[4], int *boundary)
288 {
289         int ptrs = EXT3_ADDR_PER_BLOCK(inode->i_sb);
290         int ptrs_bits = EXT3_ADDR_PER_BLOCK_BITS(inode->i_sb);
291         const long direct_blocks = EXT3_NDIR_BLOCKS,
292                 indirect_blocks = ptrs,
293                 double_blocks = (1 << (ptrs_bits * 2));
294         int n = 0;
295         int final = 0;
296
297         if (i_block < 0) {
298                 ext3_warning (inode->i_sb, "ext3_block_to_path", "block < 0");
299         } else if (i_block < direct_blocks) {
300                 offsets[n++] = i_block;
301                 final = direct_blocks;
302         } else if ( (i_block -= direct_blocks) < indirect_blocks) {
303                 offsets[n++] = EXT3_IND_BLOCK;
304                 offsets[n++] = i_block;
305                 final = ptrs;
306         } else if ((i_block -= indirect_blocks) < double_blocks) {
307                 offsets[n++] = EXT3_DIND_BLOCK;
308                 offsets[n++] = i_block >> ptrs_bits;
309                 offsets[n++] = i_block & (ptrs - 1);
310                 final = ptrs;
311         } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
312                 offsets[n++] = EXT3_TIND_BLOCK;
313                 offsets[n++] = i_block >> (ptrs_bits * 2);
314                 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
315                 offsets[n++] = i_block & (ptrs - 1);
316                 final = ptrs;
317         } else {
318                 ext3_warning(inode->i_sb, "ext3_block_to_path", "block > big");
319         }
320         if (boundary)
321                 *boundary = final - 1 - (i_block & (ptrs - 1));
322         return n;
323 }
324
325 /**
326  *      ext3_get_branch - read the chain of indirect blocks leading to data
327  *      @inode: inode in question
328  *      @depth: depth of the chain (1 - direct pointer, etc.)
329  *      @offsets: offsets of pointers in inode/indirect blocks
330  *      @chain: place to store the result
331  *      @err: here we store the error value
332  *
333  *      Function fills the array of triples <key, p, bh> and returns %NULL
334  *      if everything went OK or the pointer to the last filled triple
335  *      (incomplete one) otherwise. Upon the return chain[i].key contains
336  *      the number of (i+1)-th block in the chain (as it is stored in memory,
337  *      i.e. little-endian 32-bit), chain[i].p contains the address of that
338  *      number (it points into struct inode for i==0 and into the bh->b_data
339  *      for i>0) and chain[i].bh points to the buffer_head of i-th indirect
340  *      block for i>0 and NULL for i==0. In other words, it holds the block
341  *      numbers of the chain, addresses they were taken from (and where we can
342  *      verify that chain did not change) and buffer_heads hosting these
343  *      numbers.
344  *
345  *      Function stops when it stumbles upon zero pointer (absent block)
346  *              (pointer to last triple returned, *@err == 0)
347  *      or when it gets an IO error reading an indirect block
348  *              (ditto, *@err == -EIO)
349  *      or when it notices that chain had been changed while it was reading
350  *              (ditto, *@err == -EAGAIN)
351  *      or when it reads all @depth-1 indirect blocks successfully and finds
352  *      the whole chain, all way to the data (returns %NULL, *err == 0).
353  */
354 static Indirect *ext3_get_branch(struct inode *inode, int depth, int *offsets,
355                                  Indirect chain[4], int *err)
356 {
357         struct super_block *sb = inode->i_sb;
358         Indirect *p = chain;
359         struct buffer_head *bh;
360
361         *err = 0;
362         /* i_data is not going away, no lock needed */
363         add_chain (chain, NULL, EXT3_I(inode)->i_data + *offsets);
364         if (!p->key)
365                 goto no_block;
366         while (--depth) {
367                 bh = sb_bread(sb, le32_to_cpu(p->key));
368                 if (!bh)
369                         goto failure;
370                 /* Reader: pointers */
371                 if (!verify_chain(chain, p))
372                         goto changed;
373                 add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
374                 /* Reader: end */
375                 if (!p->key)
376                         goto no_block;
377         }
378         return NULL;
379
380 changed:
381         brelse(bh);
382         *err = -EAGAIN;
383         goto no_block;
384 failure:
385         *err = -EIO;
386 no_block:
387         return p;
388 }
389
390 /**
391  *      ext3_find_near - find a place for allocation with sufficient locality
392  *      @inode: owner
393  *      @ind: descriptor of indirect block.
394  *
395  *      This function returns the preferred place for block allocation.
396  *      It is used when heuristic for sequential allocation fails.
397  *      Rules are:
398  *        + if there is a block to the left of our position - allocate near it.
399  *        + if pointer will live in indirect block - allocate near that block.
400  *        + if pointer will live in inode - allocate in the same
401  *          cylinder group.
402  *
403  * In the latter case we colour the starting block by the callers PID to
404  * prevent it from clashing with concurrent allocations for a different inode
405  * in the same block group.   The PID is used here so that functionally related
406  * files will be close-by on-disk.
407  *
408  *      Caller must make sure that @ind is valid and will stay that way.
409  */
410 static ext3_fsblk_t ext3_find_near(struct inode *inode, Indirect *ind)
411 {
412         struct ext3_inode_info *ei = EXT3_I(inode);
413         __le32 *start = ind->bh ? (__le32*) ind->bh->b_data : ei->i_data;
414         __le32 *p;
415         ext3_fsblk_t bg_start;
416         ext3_grpblk_t colour;
417
418         /* Try to find previous block */
419         for (p = ind->p - 1; p >= start; p--) {
420                 if (*p)
421                         return le32_to_cpu(*p);
422         }
423
424         /* No such thing, so let's try location of indirect block */
425         if (ind->bh)
426                 return ind->bh->b_blocknr;
427
428         /*
429          * It is going to be referred to from the inode itself? OK, just put it
430          * into the same cylinder group then.
431          */
432         bg_start = ext3_group_first_block_no(inode->i_sb, ei->i_block_group);
433         colour = (current->pid % 16) *
434                         (EXT3_BLOCKS_PER_GROUP(inode->i_sb) / 16);
435         return bg_start + colour;
436 }
437
438 /**
439  *      ext3_find_goal - find a preferred place for allocation.
440  *      @inode: owner
441  *      @block:  block we want
442  *      @partial: pointer to the last triple within a chain
443  *
444  *      Normally this function find the preferred place for block allocation,
445  *      returns it.
446  */
447
448 static ext3_fsblk_t ext3_find_goal(struct inode *inode, long block,
449                                    Indirect *partial)
450 {
451         struct ext3_block_alloc_info *block_i;
452
453         block_i =  EXT3_I(inode)->i_block_alloc_info;
454
455         /*
456          * try the heuristic for sequential allocation,
457          * failing that at least try to get decent locality.
458          */
459         if (block_i && (block == block_i->last_alloc_logical_block + 1)
460                 && (block_i->last_alloc_physical_block != 0)) {
461                 return block_i->last_alloc_physical_block + 1;
462         }
463
464         return ext3_find_near(inode, partial);
465 }
466
467 /**
468  *      ext3_blks_to_allocate: Look up the block map and count the number
469  *      of direct blocks need to be allocated for the given branch.
470  *
471  *      @branch: chain of indirect blocks
472  *      @k: number of blocks need for indirect blocks
473  *      @blks: number of data blocks to be mapped.
474  *      @blocks_to_boundary:  the offset in the indirect block
475  *
476  *      return the total number of blocks to be allocate, including the
477  *      direct and indirect blocks.
478  */
479 static int ext3_blks_to_allocate(Indirect *branch, int k, unsigned long blks,
480                 int blocks_to_boundary)
481 {
482         unsigned long count = 0;
483
484         /*
485          * Simple case, [t,d]Indirect block(s) has not allocated yet
486          * then it's clear blocks on that path have not allocated
487          */
488         if (k > 0) {
489                 /* right now we don't handle cross boundary allocation */
490                 if (blks < blocks_to_boundary + 1)
491                         count += blks;
492                 else
493                         count += blocks_to_boundary + 1;
494                 return count;
495         }
496
497         count++;
498         while (count < blks && count <= blocks_to_boundary &&
499                 le32_to_cpu(*(branch[0].p + count)) == 0) {
500                 count++;
501         }
502         return count;
503 }
504
505 /**
506  *      ext3_alloc_blocks: multiple allocate blocks needed for a branch
507  *      @indirect_blks: the number of blocks need to allocate for indirect
508  *                      blocks
509  *
510  *      @new_blocks: on return it will store the new block numbers for
511  *      the indirect blocks(if needed) and the first direct block,
512  *      @blks:  on return it will store the total number of allocated
513  *              direct blocks
514  */
515 static int ext3_alloc_blocks(handle_t *handle, struct inode *inode,
516                         ext3_fsblk_t goal, int indirect_blks, int blks,
517                         ext3_fsblk_t new_blocks[4], int *err)
518 {
519         int target, i;
520         unsigned long count = 0;
521         int index = 0;
522         ext3_fsblk_t current_block = 0;
523         int ret = 0;
524
525         /*
526          * Here we try to allocate the requested multiple blocks at once,
527          * on a best-effort basis.
528          * To build a branch, we should allocate blocks for
529          * the indirect blocks(if not allocated yet), and at least
530          * the first direct block of this branch.  That's the
531          * minimum number of blocks need to allocate(required)
532          */
533         target = blks + indirect_blks;
534
535         while (1) {
536                 count = target;
537                 /* allocating blocks for indirect blocks and direct blocks */
538                 current_block = ext3_new_blocks(handle,inode,goal,&count,err);
539                 if (*err)
540                         goto failed_out;
541
542                 target -= count;
543                 /* allocate blocks for indirect blocks */
544                 while (index < indirect_blks && count) {
545                         new_blocks[index++] = current_block++;
546                         count--;
547                 }
548
549                 if (count > 0)
550                         break;
551         }
552
553         /* save the new block number for the first direct block */
554         new_blocks[index] = current_block;
555
556         /* total number of blocks allocated for direct blocks */
557         ret = count;
558         *err = 0;
559         return ret;
560 failed_out:
561         for (i = 0; i <index; i++)
562                 ext3_free_blocks(handle, inode, new_blocks[i], 1);
563         return ret;
564 }
565
566 /**
567  *      ext3_alloc_branch - allocate and set up a chain of blocks.
568  *      @inode: owner
569  *      @indirect_blks: number of allocated indirect blocks
570  *      @blks: number of allocated direct blocks
571  *      @offsets: offsets (in the blocks) to store the pointers to next.
572  *      @branch: place to store the chain in.
573  *
574  *      This function allocates blocks, zeroes out all but the last one,
575  *      links them into chain and (if we are synchronous) writes them to disk.
576  *      In other words, it prepares a branch that can be spliced onto the
577  *      inode. It stores the information about that chain in the branch[], in
578  *      the same format as ext3_get_branch() would do. We are calling it after
579  *      we had read the existing part of chain and partial points to the last
580  *      triple of that (one with zero ->key). Upon the exit we have the same
581  *      picture as after the successful ext3_get_block(), except that in one
582  *      place chain is disconnected - *branch->p is still zero (we did not
583  *      set the last link), but branch->key contains the number that should
584  *      be placed into *branch->p to fill that gap.
585  *
586  *      If allocation fails we free all blocks we've allocated (and forget
587  *      their buffer_heads) and return the error value the from failed
588  *      ext3_alloc_block() (normally -ENOSPC). Otherwise we set the chain
589  *      as described above and return 0.
590  */
591 static int ext3_alloc_branch(handle_t *handle, struct inode *inode,
592                         int indirect_blks, int *blks, ext3_fsblk_t goal,
593                         int *offsets, Indirect *branch)
594 {
595         int blocksize = inode->i_sb->s_blocksize;
596         int i, n = 0;
597         int err = 0;
598         struct buffer_head *bh;
599         int num;
600         ext3_fsblk_t new_blocks[4];
601         ext3_fsblk_t current_block;
602
603         num = ext3_alloc_blocks(handle, inode, goal, indirect_blks,
604                                 *blks, new_blocks, &err);
605         if (err)
606                 return err;
607
608         branch[0].key = cpu_to_le32(new_blocks[0]);
609         /*
610          * metadata blocks and data blocks are allocated.
611          */
612         for (n = 1; n <= indirect_blks;  n++) {
613                 /*
614                  * Get buffer_head for parent block, zero it out
615                  * and set the pointer to new one, then send
616                  * parent to disk.
617                  */
618                 bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
619                 branch[n].bh = bh;
620                 lock_buffer(bh);
621                 BUFFER_TRACE(bh, "call get_create_access");
622                 err = ext3_journal_get_create_access(handle, bh);
623                 if (err) {
624                         unlock_buffer(bh);
625                         brelse(bh);
626                         goto failed;
627                 }
628
629                 memset(bh->b_data, 0, blocksize);
630                 branch[n].p = (__le32 *) bh->b_data + offsets[n];
631                 branch[n].key = cpu_to_le32(new_blocks[n]);
632                 *branch[n].p = branch[n].key;
633                 if ( n == indirect_blks) {
634                         current_block = new_blocks[n];
635                         /*
636                          * End of chain, update the last new metablock of
637                          * the chain to point to the new allocated
638                          * data blocks numbers
639                          */
640                         for (i=1; i < num; i++)
641                                 *(branch[n].p + i) = cpu_to_le32(++current_block);
642                 }
643                 BUFFER_TRACE(bh, "marking uptodate");
644                 set_buffer_uptodate(bh);
645                 unlock_buffer(bh);
646
647                 BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
648                 err = ext3_journal_dirty_metadata(handle, bh);
649                 if (err)
650                         goto failed;
651         }
652         *blks = num;
653         return err;
654 failed:
655         /* Allocation failed, free what we already allocated */
656         for (i = 1; i <= n ; i++) {
657                 BUFFER_TRACE(branch[i].bh, "call journal_forget");
658                 ext3_journal_forget(handle, branch[i].bh);
659         }
660         for (i = 0; i <indirect_blks; i++)
661                 ext3_free_blocks(handle, inode, new_blocks[i], 1);
662
663         ext3_free_blocks(handle, inode, new_blocks[i], num);
664
665         return err;
666 }
667
668 /**
669  * ext3_splice_branch - splice the allocated branch onto inode.
670  * @inode: owner
671  * @block: (logical) number of block we are adding
672  * @chain: chain of indirect blocks (with a missing link - see
673  *      ext3_alloc_branch)
674  * @where: location of missing link
675  * @num:   number of indirect blocks we are adding
676  * @blks:  number of direct blocks we are adding
677  *
678  * This function fills the missing link and does all housekeeping needed in
679  * inode (->i_blocks, etc.). In case of success we end up with the full
680  * chain to new block and return 0.
681  */
682 static int ext3_splice_branch(handle_t *handle, struct inode *inode,
683                         long block, Indirect *where, int num, int blks)
684 {
685         int i;
686         int err = 0;
687         struct ext3_block_alloc_info *block_i;
688         ext3_fsblk_t current_block;
689
690         block_i = EXT3_I(inode)->i_block_alloc_info;
691         /*
692          * If we're splicing into a [td]indirect block (as opposed to the
693          * inode) then we need to get write access to the [td]indirect block
694          * before the splice.
695          */
696         if (where->bh) {
697                 BUFFER_TRACE(where->bh, "get_write_access");
698                 err = ext3_journal_get_write_access(handle, where->bh);
699                 if (err)
700                         goto err_out;
701         }
702         /* That's it */
703
704         *where->p = where->key;
705
706         /*
707          * Update the host buffer_head or inode to point to more just allocated
708          * direct blocks blocks
709          */
710         if (num == 0 && blks > 1) {
711                 current_block = le32_to_cpu(where->key) + 1;
712                 for (i = 1; i < blks; i++)
713                         *(where->p + i ) = cpu_to_le32(current_block++);
714         }
715
716         /*
717          * update the most recently allocated logical & physical block
718          * in i_block_alloc_info, to assist find the proper goal block for next
719          * allocation
720          */
721         if (block_i) {
722                 block_i->last_alloc_logical_block = block + blks - 1;
723                 block_i->last_alloc_physical_block =
724                                 le32_to_cpu(where[num].key) + blks - 1;
725         }
726
727         /* We are done with atomic stuff, now do the rest of housekeeping */
728
729         inode->i_ctime = CURRENT_TIME_SEC;
730         ext3_mark_inode_dirty(handle, inode);
731
732         /* had we spliced it onto indirect block? */
733         if (where->bh) {
734                 /*
735                  * If we spliced it onto an indirect block, we haven't
736                  * altered the inode.  Note however that if it is being spliced
737                  * onto an indirect block at the very end of the file (the
738                  * file is growing) then we *will* alter the inode to reflect
739                  * the new i_size.  But that is not done here - it is done in
740                  * generic_commit_write->__mark_inode_dirty->ext3_dirty_inode.
741                  */
742                 jbd_debug(5, "splicing indirect only\n");
743                 BUFFER_TRACE(where->bh, "call ext3_journal_dirty_metadata");
744                 err = ext3_journal_dirty_metadata(handle, where->bh);
745                 if (err)
746                         goto err_out;
747         } else {
748                 /*
749                  * OK, we spliced it into the inode itself on a direct block.
750                  * Inode was dirtied above.
751                  */
752                 jbd_debug(5, "splicing direct\n");
753         }
754         return err;
755
756 err_out:
757         for (i = 1; i <= num; i++) {
758                 BUFFER_TRACE(where[i].bh, "call journal_forget");
759                 ext3_journal_forget(handle, where[i].bh);
760                 ext3_free_blocks(handle,inode,le32_to_cpu(where[i-1].key),1);
761         }
762         ext3_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks);
763
764         return err;
765 }
766
767 /*
768  * Allocation strategy is simple: if we have to allocate something, we will
769  * have to go the whole way to leaf. So let's do it before attaching anything
770  * to tree, set linkage between the newborn blocks, write them if sync is
771  * required, recheck the path, free and repeat if check fails, otherwise
772  * set the last missing link (that will protect us from any truncate-generated
773  * removals - all blocks on the path are immune now) and possibly force the
774  * write on the parent block.
775  * That has a nice additional property: no special recovery from the failed
776  * allocations is needed - we simply release blocks and do not touch anything
777  * reachable from inode.
778  *
779  * `handle' can be NULL if create == 0.
780  *
781  * The BKL may not be held on entry here.  Be sure to take it early.
782  * return > 0, # of blocks mapped or allocated.
783  * return = 0, if plain lookup failed.
784  * return < 0, error case.
785  */
786 int ext3_get_blocks_handle(handle_t *handle, struct inode *inode,
787                 sector_t iblock, unsigned long maxblocks,
788                 struct buffer_head *bh_result,
789                 int create, int extend_disksize)
790 {
791         int err = -EIO;
792         int offsets[4];
793         Indirect chain[4];
794         Indirect *partial;
795         ext3_fsblk_t goal;
796         int indirect_blks;
797         int blocks_to_boundary = 0;
798         int depth;
799         struct ext3_inode_info *ei = EXT3_I(inode);
800         int count = 0;
801         ext3_fsblk_t first_block = 0;
802
803
804         J_ASSERT(handle != NULL || create == 0);
805         depth = ext3_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
806
807         if (depth == 0)
808                 goto out;
809
810         partial = ext3_get_branch(inode, depth, offsets, chain, &err);
811
812         /* Simplest case - block found, no allocation needed */
813         if (!partial) {
814                 first_block = le32_to_cpu(chain[depth - 1].key);
815                 clear_buffer_new(bh_result);
816                 count++;
817                 /*map more blocks*/
818                 while (count < maxblocks && count <= blocks_to_boundary) {
819                         ext3_fsblk_t blk;
820
821                         if (!verify_chain(chain, partial)) {
822                                 /*
823                                  * Indirect block might be removed by
824                                  * truncate while we were reading it.
825                                  * Handling of that case: forget what we've
826                                  * got now. Flag the err as EAGAIN, so it
827                                  * will reread.
828                                  */
829                                 err = -EAGAIN;
830                                 count = 0;
831                                 break;
832                         }
833                         blk = le32_to_cpu(*(chain[depth-1].p + count));
834
835                         if (blk == first_block + count)
836                                 count++;
837                         else
838                                 break;
839                 }
840                 if (err != -EAGAIN)
841                         goto got_it;
842         }
843
844         /* Next simple case - plain lookup or failed read of indirect block */
845         if (!create || err == -EIO)
846                 goto cleanup;
847
848         mutex_lock(&ei->truncate_mutex);
849
850         /*
851          * If the indirect block is missing while we are reading
852          * the chain(ext3_get_branch() returns -EAGAIN err), or
853          * if the chain has been changed after we grab the semaphore,
854          * (either because another process truncated this branch, or
855          * another get_block allocated this branch) re-grab the chain to see if
856          * the request block has been allocated or not.
857          *
858          * Since we already block the truncate/other get_block
859          * at this point, we will have the current copy of the chain when we
860          * splice the branch into the tree.
861          */
862         if (err == -EAGAIN || !verify_chain(chain, partial)) {
863                 while (partial > chain) {
864                         brelse(partial->bh);
865                         partial--;
866                 }
867                 partial = ext3_get_branch(inode, depth, offsets, chain, &err);
868                 if (!partial) {
869                         count++;
870                         mutex_unlock(&ei->truncate_mutex);
871                         if (err)
872                                 goto cleanup;
873                         clear_buffer_new(bh_result);
874                         goto got_it;
875                 }
876         }
877
878         /*
879          * Okay, we need to do block allocation.  Lazily initialize the block
880          * allocation info here if necessary
881         */
882         if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
883                 ext3_init_block_alloc_info(inode);
884
885         goal = ext3_find_goal(inode, iblock, partial);
886
887         /* the number of blocks need to allocate for [d,t]indirect blocks */
888         indirect_blks = (chain + depth) - partial - 1;
889
890         /*
891          * Next look up the indirect map to count the totoal number of
892          * direct blocks to allocate for this branch.
893          */
894         count = ext3_blks_to_allocate(partial, indirect_blks,
895                                         maxblocks, blocks_to_boundary);
896         /*
897          * Block out ext3_truncate while we alter the tree
898          */
899         err = ext3_alloc_branch(handle, inode, indirect_blks, &count, goal,
900                                 offsets + (partial - chain), partial);
901
902         /*
903          * The ext3_splice_branch call will free and forget any buffers
904          * on the new chain if there is a failure, but that risks using
905          * up transaction credits, especially for bitmaps where the
906          * credits cannot be returned.  Can we handle this somehow?  We
907          * may need to return -EAGAIN upwards in the worst case.  --sct
908          */
909         if (!err)
910                 err = ext3_splice_branch(handle, inode, iblock,
911                                         partial, indirect_blks, count);
912         /*
913          * i_disksize growing is protected by truncate_mutex.  Don't forget to
914          * protect it if you're about to implement concurrent
915          * ext3_get_block() -bzzz
916         */
917         if (!err && extend_disksize && inode->i_size > ei->i_disksize)
918                 ei->i_disksize = inode->i_size;
919         mutex_unlock(&ei->truncate_mutex);
920         if (err)
921                 goto cleanup;
922
923         set_buffer_new(bh_result);
924 got_it:
925         map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
926         if (count > blocks_to_boundary)
927                 set_buffer_boundary(bh_result);
928         err = count;
929         /* Clean up and exit */
930         partial = chain + depth - 1;    /* the whole chain */
931 cleanup:
932         while (partial > chain) {
933                 BUFFER_TRACE(partial->bh, "call brelse");
934                 brelse(partial->bh);
935                 partial--;
936         }
937         BUFFER_TRACE(bh_result, "returned");
938 out:
939         return err;
940 }
941
942 /* Maximum number of blocks we map for direct IO at once. */
943 #define DIO_MAX_BLOCKS 4096
944 /*
945  * Number of credits we need for writing DIO_MAX_BLOCKS:
946  * We need sb + group descriptor + bitmap + inode -> 4
947  * For B blocks with A block pointers per block we need:
948  * 1 (triple ind.) + (B/A/A + 2) (doubly ind.) + (B/A + 2) (indirect).
949  * If we plug in 4096 for B and 256 for A (for 1KB block size), we get 25.
950  */
951 #define DIO_CREDITS 25
952
953 static int ext3_get_block(struct inode *inode, sector_t iblock,
954                         struct buffer_head *bh_result, int create)
955 {
956         handle_t *handle = ext3_journal_current_handle();
957         int ret = 0, started = 0;
958         unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
959
960         if (create && !handle) {        /* Direct IO write... */
961                 if (max_blocks > DIO_MAX_BLOCKS)
962                         max_blocks = DIO_MAX_BLOCKS;
963                 handle = ext3_journal_start(inode, DIO_CREDITS +
964                                 2 * EXT3_QUOTA_TRANS_BLOCKS(inode->i_sb));
965                 if (IS_ERR(handle)) {
966                         ret = PTR_ERR(handle);
967                         goto out;
968                 }
969                 started = 1;
970         }
971
972         ret = ext3_get_blocks_handle(handle, inode, iblock,
973                                         max_blocks, bh_result, create, 0);
974         if (ret > 0) {
975                 bh_result->b_size = (ret << inode->i_blkbits);
976                 ret = 0;
977         }
978         if (started)
979                 ext3_journal_stop(handle);
980 out:
981         return ret;
982 }
983
984 /*
985  * `handle' can be NULL if create is zero
986  */
987 struct buffer_head *ext3_getblk(handle_t *handle, struct inode *inode,
988                                 long block, int create, int *errp)
989 {
990         struct buffer_head dummy;
991         int fatal = 0, err;
992
993         J_ASSERT(handle != NULL || create == 0);
994
995         dummy.b_state = 0;
996         dummy.b_blocknr = -1000;
997         buffer_trace_init(&dummy.b_history);
998         err = ext3_get_blocks_handle(handle, inode, block, 1,
999                                         &dummy, create, 1);
1000         /*
1001          * ext3_get_blocks_handle() returns number of blocks
1002          * mapped. 0 in case of a HOLE.
1003          */
1004         if (err > 0) {
1005                 if (err > 1)
1006                         WARN_ON(1);
1007                 err = 0;
1008         }
1009         *errp = err;
1010         if (!err && buffer_mapped(&dummy)) {
1011                 struct buffer_head *bh;
1012                 bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
1013                 if (!bh) {
1014                         *errp = -EIO;
1015                         goto err;
1016                 }
1017                 if (buffer_new(&dummy)) {
1018                         J_ASSERT(create != 0);
1019                         J_ASSERT(handle != NULL);
1020
1021                         /*
1022                          * Now that we do not always journal data, we should
1023                          * keep in mind whether this should always journal the
1024                          * new buffer as metadata.  For now, regular file
1025                          * writes use ext3_get_block instead, so it's not a
1026                          * problem.
1027                          */
1028                         lock_buffer(bh);
1029                         BUFFER_TRACE(bh, "call get_create_access");
1030                         fatal = ext3_journal_get_create_access(handle, bh);
1031                         if (!fatal && !buffer_uptodate(bh)) {
1032                                 memset(bh->b_data,0,inode->i_sb->s_blocksize);
1033                                 set_buffer_uptodate(bh);
1034                         }
1035                         unlock_buffer(bh);
1036                         BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
1037                         err = ext3_journal_dirty_metadata(handle, bh);
1038                         if (!fatal)
1039                                 fatal = err;
1040                 } else {
1041                         BUFFER_TRACE(bh, "not a new buffer");
1042                 }
1043                 if (fatal) {
1044                         *errp = fatal;
1045                         brelse(bh);
1046                         bh = NULL;
1047                 }
1048                 return bh;
1049         }
1050 err:
1051         return NULL;
1052 }
1053
1054 struct buffer_head *ext3_bread(handle_t *handle, struct inode *inode,
1055                                int block, int create, int *err)
1056 {
1057         struct buffer_head * bh;
1058
1059         bh = ext3_getblk(handle, inode, block, create, err);
1060         if (!bh)
1061                 return bh;
1062         if (buffer_uptodate(bh))
1063                 return bh;
1064         ll_rw_block(READ_META, 1, &bh);
1065         wait_on_buffer(bh);
1066         if (buffer_uptodate(bh))
1067                 return bh;
1068         put_bh(bh);
1069         *err = -EIO;
1070         return NULL;
1071 }
1072
1073 static int walk_page_buffers(   handle_t *handle,
1074                                 struct buffer_head *head,
1075                                 unsigned from,
1076                                 unsigned to,
1077                                 int *partial,
1078                                 int (*fn)(      handle_t *handle,
1079                                                 struct buffer_head *bh))
1080 {
1081         struct buffer_head *bh;
1082         unsigned block_start, block_end;
1083         unsigned blocksize = head->b_size;
1084         int err, ret = 0;
1085         struct buffer_head *next;
1086
1087         for (   bh = head, block_start = 0;
1088                 ret == 0 && (bh != head || !block_start);
1089                 block_start = block_end, bh = next)
1090         {
1091                 next = bh->b_this_page;
1092                 block_end = block_start + blocksize;
1093                 if (block_end <= from || block_start >= to) {
1094                         if (partial && !buffer_uptodate(bh))
1095                                 *partial = 1;
1096                         continue;
1097                 }
1098                 err = (*fn)(handle, bh);
1099                 if (!ret)
1100                         ret = err;
1101         }
1102         return ret;
1103 }
1104
1105 /*
1106  * To preserve ordering, it is essential that the hole instantiation and
1107  * the data write be encapsulated in a single transaction.  We cannot
1108  * close off a transaction and start a new one between the ext3_get_block()
1109  * and the commit_write().  So doing the journal_start at the start of
1110  * prepare_write() is the right place.
1111  *
1112  * Also, this function can nest inside ext3_writepage() ->
1113  * block_write_full_page(). In that case, we *know* that ext3_writepage()
1114  * has generated enough buffer credits to do the whole page.  So we won't
1115  * block on the journal in that case, which is good, because the caller may
1116  * be PF_MEMALLOC.
1117  *
1118  * By accident, ext3 can be reentered when a transaction is open via
1119  * quota file writes.  If we were to commit the transaction while thus
1120  * reentered, there can be a deadlock - we would be holding a quota
1121  * lock, and the commit would never complete if another thread had a
1122  * transaction open and was blocking on the quota lock - a ranking
1123  * violation.
1124  *
1125  * So what we do is to rely on the fact that journal_stop/journal_start
1126  * will _not_ run commit under these circumstances because handle->h_ref
1127  * is elevated.  We'll still have enough credits for the tiny quotafile
1128  * write.
1129  */
1130 static int do_journal_get_write_access(handle_t *handle,
1131                                         struct buffer_head *bh)
1132 {
1133         if (!buffer_mapped(bh) || buffer_freed(bh))
1134                 return 0;
1135         return ext3_journal_get_write_access(handle, bh);
1136 }
1137
1138 static int ext3_write_begin(struct file *file, struct address_space *mapping,
1139                                 loff_t pos, unsigned len, unsigned flags,
1140                                 struct page **pagep, void **fsdata)
1141 {
1142         struct inode *inode = mapping->host;
1143         int ret, needed_blocks = ext3_writepage_trans_blocks(inode);
1144         handle_t *handle;
1145         int retries = 0;
1146         struct page *page;
1147         pgoff_t index;
1148         unsigned from, to;
1149
1150         index = pos >> PAGE_CACHE_SHIFT;
1151         from = pos & (PAGE_CACHE_SIZE - 1);
1152         to = from + len;
1153
1154 retry:
1155         page = __grab_cache_page(mapping, index);
1156         if (!page)
1157                 return -ENOMEM;
1158         *pagep = page;
1159
1160         handle = ext3_journal_start(inode, needed_blocks);
1161         if (IS_ERR(handle)) {
1162                 unlock_page(page);
1163                 page_cache_release(page);
1164                 ret = PTR_ERR(handle);
1165                 goto out;
1166         }
1167         ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
1168                                                         ext3_get_block);
1169         if (ret)
1170                 goto write_begin_failed;
1171
1172         if (ext3_should_journal_data(inode)) {
1173                 ret = walk_page_buffers(handle, page_buffers(page),
1174                                 from, to, NULL, do_journal_get_write_access);
1175         }
1176 write_begin_failed:
1177         if (ret) {
1178                 ext3_journal_stop(handle);
1179                 unlock_page(page);
1180                 page_cache_release(page);
1181         }
1182         if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
1183                 goto retry;
1184 out:
1185         return ret;
1186 }
1187
1188
1189 int ext3_journal_dirty_data(handle_t *handle, struct buffer_head *bh)
1190 {
1191         int err = journal_dirty_data(handle, bh);
1192         if (err)
1193                 ext3_journal_abort_handle(__func__, __func__,
1194                                                 bh, handle, err);
1195         return err;
1196 }
1197
1198 /* For write_end() in data=journal mode */
1199 static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1200 {
1201         if (!buffer_mapped(bh) || buffer_freed(bh))
1202                 return 0;
1203         set_buffer_uptodate(bh);
1204         return ext3_journal_dirty_metadata(handle, bh);
1205 }
1206
1207 /*
1208  * Generic write_end handler for ordered and writeback ext3 journal modes.
1209  * We can't use generic_write_end, because that unlocks the page and we need to
1210  * unlock the page after ext3_journal_stop, but ext3_journal_stop must run
1211  * after block_write_end.
1212  */
1213 static int ext3_generic_write_end(struct file *file,
1214                                 struct address_space *mapping,
1215                                 loff_t pos, unsigned len, unsigned copied,
1216                                 struct page *page, void *fsdata)
1217 {
1218         struct inode *inode = file->f_mapping->host;
1219
1220         copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
1221
1222         if (pos+copied > inode->i_size) {
1223                 i_size_write(inode, pos+copied);
1224                 mark_inode_dirty(inode);
1225         }
1226
1227         return copied;
1228 }
1229
1230 /*
1231  * We need to pick up the new inode size which generic_commit_write gave us
1232  * `file' can be NULL - eg, when called from page_symlink().
1233  *
1234  * ext3 never places buffers on inode->i_mapping->private_list.  metadata
1235  * buffers are managed internally.
1236  */
1237 static int ext3_ordered_write_end(struct file *file,
1238                                 struct address_space *mapping,
1239                                 loff_t pos, unsigned len, unsigned copied,
1240                                 struct page *page, void *fsdata)
1241 {
1242         handle_t *handle = ext3_journal_current_handle();
1243         struct inode *inode = file->f_mapping->host;
1244         unsigned from, to;
1245         int ret = 0, ret2;
1246
1247         from = pos & (PAGE_CACHE_SIZE - 1);
1248         to = from + len;
1249
1250         ret = walk_page_buffers(handle, page_buffers(page),
1251                 from, to, NULL, ext3_journal_dirty_data);
1252
1253         if (ret == 0) {
1254                 /*
1255                  * generic_write_end() will run mark_inode_dirty() if i_size
1256                  * changes.  So let's piggyback the i_disksize mark_inode_dirty
1257                  * into that.
1258                  */
1259                 loff_t new_i_size;
1260
1261                 new_i_size = pos + copied;
1262                 if (new_i_size > EXT3_I(inode)->i_disksize)
1263                         EXT3_I(inode)->i_disksize = new_i_size;
1264                 ret2 = ext3_generic_write_end(file, mapping, pos, len, copied,
1265                                                         page, fsdata);
1266                 copied = ret2;
1267                 if (ret2 < 0)
1268                         ret = ret2;
1269         }
1270         ret2 = ext3_journal_stop(handle);
1271         if (!ret)
1272                 ret = ret2;
1273         unlock_page(page);
1274         page_cache_release(page);
1275
1276         return ret ? ret : copied;
1277 }
1278
1279 static int ext3_writeback_write_end(struct file *file,
1280                                 struct address_space *mapping,
1281                                 loff_t pos, unsigned len, unsigned copied,
1282                                 struct page *page, void *fsdata)
1283 {
1284         handle_t *handle = ext3_journal_current_handle();
1285         struct inode *inode = file->f_mapping->host;
1286         int ret = 0, ret2;
1287         loff_t new_i_size;
1288
1289         new_i_size = pos + copied;
1290         if (new_i_size > EXT3_I(inode)->i_disksize)
1291                 EXT3_I(inode)->i_disksize = new_i_size;
1292
1293         ret2 = ext3_generic_write_end(file, mapping, pos, len, copied,
1294                                                         page, fsdata);
1295         copied = ret2;
1296         if (ret2 < 0)
1297                 ret = ret2;
1298
1299         ret2 = ext3_journal_stop(handle);
1300         if (!ret)
1301                 ret = ret2;
1302         unlock_page(page);
1303         page_cache_release(page);
1304
1305         return ret ? ret : copied;
1306 }
1307
1308 static int ext3_journalled_write_end(struct file *file,
1309                                 struct address_space *mapping,
1310                                 loff_t pos, unsigned len, unsigned copied,
1311                                 struct page *page, void *fsdata)
1312 {
1313         handle_t *handle = ext3_journal_current_handle();
1314         struct inode *inode = mapping->host;
1315         int ret = 0, ret2;
1316         int partial = 0;
1317         unsigned from, to;
1318
1319         from = pos & (PAGE_CACHE_SIZE - 1);
1320         to = from + len;
1321
1322         if (copied < len) {
1323                 if (!PageUptodate(page))
1324                         copied = 0;
1325                 page_zero_new_buffers(page, from+copied, to);
1326         }
1327
1328         ret = walk_page_buffers(handle, page_buffers(page), from,
1329                                 to, &partial, write_end_fn);
1330         if (!partial)
1331                 SetPageUptodate(page);
1332         if (pos+copied > inode->i_size)
1333                 i_size_write(inode, pos+copied);
1334         EXT3_I(inode)->i_state |= EXT3_STATE_JDATA;
1335         if (inode->i_size > EXT3_I(inode)->i_disksize) {
1336                 EXT3_I(inode)->i_disksize = inode->i_size;
1337                 ret2 = ext3_mark_inode_dirty(handle, inode);
1338                 if (!ret)
1339                         ret = ret2;
1340         }
1341
1342         ret2 = ext3_journal_stop(handle);
1343         if (!ret)
1344                 ret = ret2;
1345         unlock_page(page);
1346         page_cache_release(page);
1347
1348         return ret ? ret : copied;
1349 }
1350
1351 /*
1352  * bmap() is special.  It gets used by applications such as lilo and by
1353  * the swapper to find the on-disk block of a specific piece of data.
1354  *
1355  * Naturally, this is dangerous if the block concerned is still in the
1356  * journal.  If somebody makes a swapfile on an ext3 data-journaling
1357  * filesystem and enables swap, then they may get a nasty shock when the
1358  * data getting swapped to that swapfile suddenly gets overwritten by
1359  * the original zero's written out previously to the journal and
1360  * awaiting writeback in the kernel's buffer cache.
1361  *
1362  * So, if we see any bmap calls here on a modified, data-journaled file,
1363  * take extra steps to flush any blocks which might be in the cache.
1364  */
1365 static sector_t ext3_bmap(struct address_space *mapping, sector_t block)
1366 {
1367         struct inode *inode = mapping->host;
1368         journal_t *journal;
1369         int err;
1370
1371         if (EXT3_I(inode)->i_state & EXT3_STATE_JDATA) {
1372                 /*
1373                  * This is a REALLY heavyweight approach, but the use of
1374                  * bmap on dirty files is expected to be extremely rare:
1375                  * only if we run lilo or swapon on a freshly made file
1376                  * do we expect this to happen.
1377                  *
1378                  * (bmap requires CAP_SYS_RAWIO so this does not
1379                  * represent an unprivileged user DOS attack --- we'd be
1380                  * in trouble if mortal users could trigger this path at
1381                  * will.)
1382                  *
1383                  * NB. EXT3_STATE_JDATA is not set on files other than
1384                  * regular files.  If somebody wants to bmap a directory
1385                  * or symlink and gets confused because the buffer
1386                  * hasn't yet been flushed to disk, they deserve
1387                  * everything they get.
1388                  */
1389
1390                 EXT3_I(inode)->i_state &= ~EXT3_STATE_JDATA;
1391                 journal = EXT3_JOURNAL(inode);
1392                 journal_lock_updates(journal);
1393                 err = journal_flush(journal);
1394                 journal_unlock_updates(journal);
1395
1396                 if (err)
1397                         return 0;
1398         }
1399
1400         return generic_block_bmap(mapping,block,ext3_get_block);
1401 }
1402
1403 static int bget_one(handle_t *handle, struct buffer_head *bh)
1404 {
1405         get_bh(bh);
1406         return 0;
1407 }
1408
1409 static int bput_one(handle_t *handle, struct buffer_head *bh)
1410 {
1411         put_bh(bh);
1412         return 0;
1413 }
1414
1415 static int journal_dirty_data_fn(handle_t *handle, struct buffer_head *bh)
1416 {
1417         if (buffer_mapped(bh))
1418                 return ext3_journal_dirty_data(handle, bh);
1419         return 0;
1420 }
1421
1422 /*
1423  * Note that we always start a transaction even if we're not journalling
1424  * data.  This is to preserve ordering: any hole instantiation within
1425  * __block_write_full_page -> ext3_get_block() should be journalled
1426  * along with the data so we don't crash and then get metadata which
1427  * refers to old data.
1428  *
1429  * In all journalling modes block_write_full_page() will start the I/O.
1430  *
1431  * Problem:
1432  *
1433  *      ext3_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
1434  *              ext3_writepage()
1435  *
1436  * Similar for:
1437  *
1438  *      ext3_file_write() -> generic_file_write() -> __alloc_pages() -> ...
1439  *
1440  * Same applies to ext3_get_block().  We will deadlock on various things like
1441  * lock_journal and i_truncate_mutex.
1442  *
1443  * Setting PF_MEMALLOC here doesn't work - too many internal memory
1444  * allocations fail.
1445  *
1446  * 16May01: If we're reentered then journal_current_handle() will be
1447  *          non-zero. We simply *return*.
1448  *
1449  * 1 July 2001: @@@ FIXME:
1450  *   In journalled data mode, a data buffer may be metadata against the
1451  *   current transaction.  But the same file is part of a shared mapping
1452  *   and someone does a writepage() on it.
1453  *
1454  *   We will move the buffer onto the async_data list, but *after* it has
1455  *   been dirtied. So there's a small window where we have dirty data on
1456  *   BJ_Metadata.
1457  *
1458  *   Note that this only applies to the last partial page in the file.  The
1459  *   bit which block_write_full_page() uses prepare/commit for.  (That's
1460  *   broken code anyway: it's wrong for msync()).
1461  *
1462  *   It's a rare case: affects the final partial page, for journalled data
1463  *   where the file is subject to bith write() and writepage() in the same
1464  *   transction.  To fix it we'll need a custom block_write_full_page().
1465  *   We'll probably need that anyway for journalling writepage() output.
1466  *
1467  * We don't honour synchronous mounts for writepage().  That would be
1468  * disastrous.  Any write() or metadata operation will sync the fs for
1469  * us.
1470  *
1471  * AKPM2: if all the page's buffers are mapped to disk and !data=journal,
1472  * we don't need to open a transaction here.
1473  */
1474 static int ext3_ordered_writepage(struct page *page,
1475                                 struct writeback_control *wbc)
1476 {
1477         struct inode *inode = page->mapping->host;
1478         struct buffer_head *page_bufs;
1479         handle_t *handle = NULL;
1480         int ret = 0;
1481         int err;
1482
1483         J_ASSERT(PageLocked(page));
1484
1485         /*
1486          * We give up here if we're reentered, because it might be for a
1487          * different filesystem.
1488          */
1489         if (ext3_journal_current_handle())
1490                 goto out_fail;
1491
1492         handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
1493
1494         if (IS_ERR(handle)) {
1495                 ret = PTR_ERR(handle);
1496                 goto out_fail;
1497         }
1498
1499         if (!page_has_buffers(page)) {
1500                 create_empty_buffers(page, inode->i_sb->s_blocksize,
1501                                 (1 << BH_Dirty)|(1 << BH_Uptodate));
1502         }
1503         page_bufs = page_buffers(page);
1504         walk_page_buffers(handle, page_bufs, 0,
1505                         PAGE_CACHE_SIZE, NULL, bget_one);
1506
1507         ret = block_write_full_page(page, ext3_get_block, wbc);
1508
1509         /*
1510          * The page can become unlocked at any point now, and
1511          * truncate can then come in and change things.  So we
1512          * can't touch *page from now on.  But *page_bufs is
1513          * safe due to elevated refcount.
1514          */
1515
1516         /*
1517          * And attach them to the current transaction.  But only if
1518          * block_write_full_page() succeeded.  Otherwise they are unmapped,
1519          * and generally junk.
1520          */
1521         if (ret == 0) {
1522                 err = walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE,
1523                                         NULL, journal_dirty_data_fn);
1524                 if (!ret)
1525                         ret = err;
1526         }
1527         walk_page_buffers(handle, page_bufs, 0,
1528                         PAGE_CACHE_SIZE, NULL, bput_one);
1529         err = ext3_journal_stop(handle);
1530         if (!ret)
1531                 ret = err;
1532         return ret;
1533
1534 out_fail:
1535         redirty_page_for_writepage(wbc, page);
1536         unlock_page(page);
1537         return ret;
1538 }
1539
1540 static int ext3_writeback_writepage(struct page *page,
1541                                 struct writeback_control *wbc)
1542 {
1543         struct inode *inode = page->mapping->host;
1544         handle_t *handle = NULL;
1545         int ret = 0;
1546         int err;
1547
1548         if (ext3_journal_current_handle())
1549                 goto out_fail;
1550
1551         handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
1552         if (IS_ERR(handle)) {
1553                 ret = PTR_ERR(handle);
1554                 goto out_fail;
1555         }
1556
1557         if (test_opt(inode->i_sb, NOBH) && ext3_should_writeback_data(inode))
1558                 ret = nobh_writepage(page, ext3_get_block, wbc);
1559         else
1560                 ret = block_write_full_page(page, ext3_get_block, wbc);
1561
1562         err = ext3_journal_stop(handle);
1563         if (!ret)
1564                 ret = err;
1565         return ret;
1566
1567 out_fail:
1568         redirty_page_for_writepage(wbc, page);
1569         unlock_page(page);
1570         return ret;
1571 }
1572
1573 static int ext3_journalled_writepage(struct page *page,
1574                                 struct writeback_control *wbc)
1575 {
1576         struct inode *inode = page->mapping->host;
1577         handle_t *handle = NULL;
1578         int ret = 0;
1579         int err;
1580
1581         if (ext3_journal_current_handle())
1582                 goto no_write;
1583
1584         handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
1585         if (IS_ERR(handle)) {
1586                 ret = PTR_ERR(handle);
1587                 goto no_write;
1588         }
1589
1590         if (!page_has_buffers(page) || PageChecked(page)) {
1591                 /*
1592                  * It's mmapped pagecache.  Add buffers and journal it.  There
1593                  * doesn't seem much point in redirtying the page here.
1594                  */
1595                 ClearPageChecked(page);
1596                 ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
1597                                         ext3_get_block);
1598                 if (ret != 0) {
1599                         ext3_journal_stop(handle);
1600                         goto out_unlock;
1601                 }
1602                 ret = walk_page_buffers(handle, page_buffers(page), 0,
1603                         PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
1604
1605                 err = walk_page_buffers(handle, page_buffers(page), 0,
1606                                 PAGE_CACHE_SIZE, NULL, write_end_fn);
1607                 if (ret == 0)
1608                         ret = err;
1609                 EXT3_I(inode)->i_state |= EXT3_STATE_JDATA;
1610                 unlock_page(page);
1611         } else {
1612                 /*
1613                  * It may be a page full of checkpoint-mode buffers.  We don't
1614                  * really know unless we go poke around in the buffer_heads.
1615                  * But block_write_full_page will do the right thing.
1616                  */
1617                 ret = block_write_full_page(page, ext3_get_block, wbc);
1618         }
1619         err = ext3_journal_stop(handle);
1620         if (!ret)
1621                 ret = err;
1622 out:
1623         return ret;
1624
1625 no_write:
1626         redirty_page_for_writepage(wbc, page);
1627 out_unlock:
1628         unlock_page(page);
1629         goto out;
1630 }
1631
1632 static int ext3_readpage(struct file *file, struct page *page)
1633 {
1634         return mpage_readpage(page, ext3_get_block);
1635 }
1636
1637 static int
1638 ext3_readpages(struct file *file, struct address_space *mapping,
1639                 struct list_head *pages, unsigned nr_pages)
1640 {
1641         return mpage_readpages(mapping, pages, nr_pages, ext3_get_block);
1642 }
1643
1644 static void ext3_invalidatepage(struct page *page, unsigned long offset)
1645 {
1646         journal_t *journal = EXT3_JOURNAL(page->mapping->host);
1647
1648         /*
1649          * If it's a full truncate we just forget about the pending dirtying
1650          */
1651         if (offset == 0)
1652                 ClearPageChecked(page);
1653
1654         journal_invalidatepage(journal, page, offset);
1655 }
1656
1657 static int ext3_releasepage(struct page *page, gfp_t wait)
1658 {
1659         journal_t *journal = EXT3_JOURNAL(page->mapping->host);
1660
1661         WARN_ON(PageChecked(page));
1662         if (!page_has_buffers(page))
1663                 return 0;
1664         return journal_try_to_free_buffers(journal, page, wait);
1665 }
1666
1667 /*
1668  * If the O_DIRECT write will extend the file then add this inode to the
1669  * orphan list.  So recovery will truncate it back to the original size
1670  * if the machine crashes during the write.
1671  *
1672  * If the O_DIRECT write is intantiating holes inside i_size and the machine
1673  * crashes then stale disk data _may_ be exposed inside the file. But current
1674  * VFS code falls back into buffered path in that case so we are safe.
1675  */
1676 static ssize_t ext3_direct_IO(int rw, struct kiocb *iocb,
1677                         const struct iovec *iov, loff_t offset,
1678                         unsigned long nr_segs)
1679 {
1680         struct file *file = iocb->ki_filp;
1681         struct inode *inode = file->f_mapping->host;
1682         struct ext3_inode_info *ei = EXT3_I(inode);
1683         handle_t *handle;
1684         ssize_t ret;
1685         int orphan = 0;
1686         size_t count = iov_length(iov, nr_segs);
1687
1688         if (rw == WRITE) {
1689                 loff_t final_size = offset + count;
1690
1691                 if (final_size > inode->i_size) {
1692                         /* Credits for sb + inode write */
1693                         handle = ext3_journal_start(inode, 2);
1694                         if (IS_ERR(handle)) {
1695                                 ret = PTR_ERR(handle);
1696                                 goto out;
1697                         }
1698                         ret = ext3_orphan_add(handle, inode);
1699                         if (ret) {
1700                                 ext3_journal_stop(handle);
1701                                 goto out;
1702                         }
1703                         orphan = 1;
1704                         ei->i_disksize = inode->i_size;
1705                         ext3_journal_stop(handle);
1706                 }
1707         }
1708
1709         ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
1710                                  offset, nr_segs,
1711                                  ext3_get_block, NULL);
1712
1713         if (orphan) {
1714                 int err;
1715
1716                 /* Credits for sb + inode write */
1717                 handle = ext3_journal_start(inode, 2);
1718                 if (IS_ERR(handle)) {
1719                         /* This is really bad luck. We've written the data
1720                          * but cannot extend i_size. Bail out and pretend
1721                          * the write failed... */
1722                         ret = PTR_ERR(handle);
1723                         goto out;
1724                 }
1725                 if (inode->i_nlink)
1726                         ext3_orphan_del(handle, inode);
1727                 if (ret > 0) {
1728                         loff_t end = offset + ret;
1729                         if (end > inode->i_size) {
1730                                 ei->i_disksize = end;
1731                                 i_size_write(inode, end);
1732                                 /*
1733                                  * We're going to return a positive `ret'
1734                                  * here due to non-zero-length I/O, so there's
1735                                  * no way of reporting error returns from
1736                                  * ext3_mark_inode_dirty() to userspace.  So
1737                                  * ignore it.
1738                                  */
1739                                 ext3_mark_inode_dirty(handle, inode);
1740                         }
1741                 }
1742                 err = ext3_journal_stop(handle);
1743                 if (ret == 0)
1744                         ret = err;
1745         }
1746 out:
1747         return ret;
1748 }
1749
1750 /*
1751  * Pages can be marked dirty completely asynchronously from ext3's journalling
1752  * activity.  By filemap_sync_pte(), try_to_unmap_one(), etc.  We cannot do
1753  * much here because ->set_page_dirty is called under VFS locks.  The page is
1754  * not necessarily locked.
1755  *
1756  * We cannot just dirty the page and leave attached buffers clean, because the
1757  * buffers' dirty state is "definitive".  We cannot just set the buffers dirty
1758  * or jbddirty because all the journalling code will explode.
1759  *
1760  * So what we do is to mark the page "pending dirty" and next time writepage
1761  * is called, propagate that into the buffers appropriately.
1762  */
1763 static int ext3_journalled_set_page_dirty(struct page *page)
1764 {
1765         SetPageChecked(page);
1766         return __set_page_dirty_nobuffers(page);
1767 }
1768
1769 static const struct address_space_operations ext3_ordered_aops = {
1770         .readpage       = ext3_readpage,
1771         .readpages      = ext3_readpages,
1772         .writepage      = ext3_ordered_writepage,
1773         .sync_page      = block_sync_page,
1774         .write_begin    = ext3_write_begin,
1775         .write_end      = ext3_ordered_write_end,
1776         .bmap           = ext3_bmap,
1777         .invalidatepage = ext3_invalidatepage,
1778         .releasepage    = ext3_releasepage,
1779         .direct_IO      = ext3_direct_IO,
1780         .migratepage    = buffer_migrate_page,
1781 };
1782
1783 static const struct address_space_operations ext3_writeback_aops = {
1784         .readpage       = ext3_readpage,
1785         .readpages      = ext3_readpages,
1786         .writepage      = ext3_writeback_writepage,
1787         .sync_page      = block_sync_page,
1788         .write_begin    = ext3_write_begin,
1789         .write_end      = ext3_writeback_write_end,
1790         .bmap           = ext3_bmap,
1791         .invalidatepage = ext3_invalidatepage,
1792         .releasepage    = ext3_releasepage,
1793         .direct_IO      = ext3_direct_IO,
1794         .migratepage    = buffer_migrate_page,
1795 };
1796
1797 static const struct address_space_operations ext3_journalled_aops = {
1798         .readpage       = ext3_readpage,
1799         .readpages      = ext3_readpages,
1800         .writepage      = ext3_journalled_writepage,
1801         .sync_page      = block_sync_page,
1802         .write_begin    = ext3_write_begin,
1803         .write_end      = ext3_journalled_write_end,
1804         .set_page_dirty = ext3_journalled_set_page_dirty,
1805         .bmap           = ext3_bmap,
1806         .invalidatepage = ext3_invalidatepage,
1807         .releasepage    = ext3_releasepage,
1808 };
1809
1810 void ext3_set_aops(struct inode *inode)
1811 {
1812         if (ext3_should_order_data(inode))
1813                 inode->i_mapping->a_ops = &ext3_ordered_aops;
1814         else if (ext3_should_writeback_data(inode))
1815                 inode->i_mapping->a_ops = &ext3_writeback_aops;
1816         else
1817                 inode->i_mapping->a_ops = &ext3_journalled_aops;
1818 }
1819
1820 /*
1821  * ext3_block_truncate_page() zeroes out a mapping from file offset `from'
1822  * up to the end of the block which corresponds to `from'.
1823  * This required during truncate. We need to physically zero the tail end
1824  * of that block so it doesn't yield old data if the file is later grown.
1825  */
1826 static int ext3_block_truncate_page(handle_t *handle, struct page *page,
1827                 struct address_space *mapping, loff_t from)
1828 {
1829         ext3_fsblk_t index = from >> PAGE_CACHE_SHIFT;
1830         unsigned offset = from & (PAGE_CACHE_SIZE-1);
1831         unsigned blocksize, iblock, length, pos;
1832         struct inode *inode = mapping->host;
1833         struct buffer_head *bh;
1834         int err = 0;
1835
1836         blocksize = inode->i_sb->s_blocksize;
1837         length = blocksize - (offset & (blocksize - 1));
1838         iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
1839
1840         /*
1841          * For "nobh" option,  we can only work if we don't need to
1842          * read-in the page - otherwise we create buffers to do the IO.
1843          */
1844         if (!page_has_buffers(page) && test_opt(inode->i_sb, NOBH) &&
1845              ext3_should_writeback_data(inode) && PageUptodate(page)) {
1846                 zero_user(page, offset, length);
1847                 set_page_dirty(page);
1848                 goto unlock;
1849         }
1850
1851         if (!page_has_buffers(page))
1852                 create_empty_buffers(page, blocksize, 0);
1853
1854         /* Find the buffer that contains "offset" */
1855         bh = page_buffers(page);
1856         pos = blocksize;
1857         while (offset >= pos) {
1858                 bh = bh->b_this_page;
1859                 iblock++;
1860                 pos += blocksize;
1861         }
1862
1863         err = 0;
1864         if (buffer_freed(bh)) {
1865                 BUFFER_TRACE(bh, "freed: skip");
1866                 goto unlock;
1867         }
1868
1869         if (!buffer_mapped(bh)) {
1870                 BUFFER_TRACE(bh, "unmapped");
1871                 ext3_get_block(inode, iblock, bh, 0);
1872                 /* unmapped? It's a hole - nothing to do */
1873                 if (!buffer_mapped(bh)) {
1874                         BUFFER_TRACE(bh, "still unmapped");
1875                         goto unlock;
1876                 }
1877         }
1878
1879         /* Ok, it's mapped. Make sure it's up-to-date */
1880         if (PageUptodate(page))
1881                 set_buffer_uptodate(bh);
1882
1883         if (!buffer_uptodate(bh)) {
1884                 err = -EIO;
1885                 ll_rw_block(READ, 1, &bh);
1886                 wait_on_buffer(bh);
1887                 /* Uhhuh. Read error. Complain and punt. */
1888                 if (!buffer_uptodate(bh))
1889                         goto unlock;
1890         }
1891
1892         if (ext3_should_journal_data(inode)) {
1893                 BUFFER_TRACE(bh, "get write access");
1894                 err = ext3_journal_get_write_access(handle, bh);
1895                 if (err)
1896                         goto unlock;
1897         }
1898
1899         zero_user(page, offset, length);
1900         BUFFER_TRACE(bh, "zeroed end of block");
1901
1902         err = 0;
1903         if (ext3_should_journal_data(inode)) {
1904                 err = ext3_journal_dirty_metadata(handle, bh);
1905         } else {
1906                 if (ext3_should_order_data(inode))
1907                         err = ext3_journal_dirty_data(handle, bh);
1908                 mark_buffer_dirty(bh);
1909         }
1910
1911 unlock:
1912         unlock_page(page);
1913         page_cache_release(page);
1914         return err;
1915 }
1916
1917 /*
1918  * Probably it should be a library function... search for first non-zero word
1919  * or memcmp with zero_page, whatever is better for particular architecture.
1920  * Linus?
1921  */
1922 static inline int all_zeroes(__le32 *p, __le32 *q)
1923 {
1924         while (p < q)
1925                 if (*p++)
1926                         return 0;
1927         return 1;
1928 }
1929
1930 /**
1931  *      ext3_find_shared - find the indirect blocks for partial truncation.
1932  *      @inode:   inode in question
1933  *      @depth:   depth of the affected branch
1934  *      @offsets: offsets of pointers in that branch (see ext3_block_to_path)
1935  *      @chain:   place to store the pointers to partial indirect blocks
1936  *      @top:     place to the (detached) top of branch
1937  *
1938  *      This is a helper function used by ext3_truncate().
1939  *
1940  *      When we do truncate() we may have to clean the ends of several
1941  *      indirect blocks but leave the blocks themselves alive. Block is
1942  *      partially truncated if some data below the new i_size is refered
1943  *      from it (and it is on the path to the first completely truncated
1944  *      data block, indeed).  We have to free the top of that path along
1945  *      with everything to the right of the path. Since no allocation
1946  *      past the truncation point is possible until ext3_truncate()
1947  *      finishes, we may safely do the latter, but top of branch may
1948  *      require special attention - pageout below the truncation point
1949  *      might try to populate it.
1950  *
1951  *      We atomically detach the top of branch from the tree, store the
1952  *      block number of its root in *@top, pointers to buffer_heads of
1953  *      partially truncated blocks - in @chain[].bh and pointers to
1954  *      their last elements that should not be removed - in
1955  *      @chain[].p. Return value is the pointer to last filled element
1956  *      of @chain.
1957  *
1958  *      The work left to caller to do the actual freeing of subtrees:
1959  *              a) free the subtree starting from *@top
1960  *              b) free the subtrees whose roots are stored in
1961  *                      (@chain[i].p+1 .. end of @chain[i].bh->b_data)
1962  *              c) free the subtrees growing from the inode past the @chain[0].
1963  *                      (no partially truncated stuff there).  */
1964
1965 static Indirect *ext3_find_shared(struct inode *inode, int depth,
1966                         int offsets[4], Indirect chain[4], __le32 *top)
1967 {
1968         Indirect *partial, *p;
1969         int k, err;
1970
1971         *top = 0;
1972         /* Make k index the deepest non-null offest + 1 */
1973         for (k = depth; k > 1 && !offsets[k-1]; k--)
1974                 ;
1975         partial = ext3_get_branch(inode, k, offsets, chain, &err);
1976         /* Writer: pointers */
1977         if (!partial)
1978                 partial = chain + k-1;
1979         /*
1980          * If the branch acquired continuation since we've looked at it -
1981          * fine, it should all survive and (new) top doesn't belong to us.
1982          */
1983         if (!partial->key && *partial->p)
1984                 /* Writer: end */
1985                 goto no_top;
1986         for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
1987                 ;
1988         /*
1989          * OK, we've found the last block that must survive. The rest of our
1990          * branch should be detached before unlocking. However, if that rest
1991          * of branch is all ours and does not grow immediately from the inode
1992          * it's easier to cheat and just decrement partial->p.
1993          */
1994         if (p == chain + k - 1 && p > chain) {
1995                 p->p--;
1996         } else {
1997                 *top = *p->p;
1998                 /* Nope, don't do this in ext3.  Must leave the tree intact */
1999 #if 0
2000                 *p->p = 0;
2001 #endif
2002         }
2003         /* Writer: end */
2004
2005         while(partial > p) {
2006                 brelse(partial->bh);
2007                 partial--;
2008         }
2009 no_top:
2010         return partial;
2011 }
2012
2013 /*
2014  * Zero a number of block pointers in either an inode or an indirect block.
2015  * If we restart the transaction we must again get write access to the
2016  * indirect block for further modification.
2017  *
2018  * We release `count' blocks on disk, but (last - first) may be greater
2019  * than `count' because there can be holes in there.
2020  */
2021 static void ext3_clear_blocks(handle_t *handle, struct inode *inode,
2022                 struct buffer_head *bh, ext3_fsblk_t block_to_free,
2023                 unsigned long count, __le32 *first, __le32 *last)
2024 {
2025         __le32 *p;
2026         if (try_to_extend_transaction(handle, inode)) {
2027                 if (bh) {
2028                         BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
2029                         ext3_journal_dirty_metadata(handle, bh);
2030                 }
2031                 ext3_mark_inode_dirty(handle, inode);
2032                 ext3_journal_test_restart(handle, inode);
2033                 if (bh) {
2034                         BUFFER_TRACE(bh, "retaking write access");
2035                         ext3_journal_get_write_access(handle, bh);
2036                 }
2037         }
2038
2039         /*
2040          * Any buffers which are on the journal will be in memory. We find
2041          * them on the hash table so journal_revoke() will run journal_forget()
2042          * on them.  We've already detached each block from the file, so
2043          * bforget() in journal_forget() should be safe.
2044          *
2045          * AKPM: turn on bforget in journal_forget()!!!
2046          */
2047         for (p = first; p < last; p++) {
2048                 u32 nr = le32_to_cpu(*p);
2049                 if (nr) {
2050                         struct buffer_head *bh;
2051
2052                         *p = 0;
2053                         bh = sb_find_get_block(inode->i_sb, nr);
2054                         ext3_forget(handle, 0, inode, bh, nr);
2055                 }
2056         }
2057
2058         ext3_free_blocks(handle, inode, block_to_free, count);
2059 }
2060
2061 /**
2062  * ext3_free_data - free a list of data blocks
2063  * @handle:     handle for this transaction
2064  * @inode:      inode we are dealing with
2065  * @this_bh:    indirect buffer_head which contains *@first and *@last
2066  * @first:      array of block numbers
2067  * @last:       points immediately past the end of array
2068  *
2069  * We are freeing all blocks refered from that array (numbers are stored as
2070  * little-endian 32-bit) and updating @inode->i_blocks appropriately.
2071  *
2072  * We accumulate contiguous runs of blocks to free.  Conveniently, if these
2073  * blocks are contiguous then releasing them at one time will only affect one
2074  * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
2075  * actually use a lot of journal space.
2076  *
2077  * @this_bh will be %NULL if @first and @last point into the inode's direct
2078  * block pointers.
2079  */
2080 static void ext3_free_data(handle_t *handle, struct inode *inode,
2081                            struct buffer_head *this_bh,
2082                            __le32 *first, __le32 *last)
2083 {
2084         ext3_fsblk_t block_to_free = 0;    /* Starting block # of a run */
2085         unsigned long count = 0;            /* Number of blocks in the run */
2086         __le32 *block_to_free_p = NULL;     /* Pointer into inode/ind
2087                                                corresponding to
2088                                                block_to_free */
2089         ext3_fsblk_t nr;                    /* Current block # */
2090         __le32 *p;                          /* Pointer into inode/ind
2091                                                for current block */
2092         int err;
2093
2094         if (this_bh) {                          /* For indirect block */
2095                 BUFFER_TRACE(this_bh, "get_write_access");
2096                 err = ext3_journal_get_write_access(handle, this_bh);
2097                 /* Important: if we can't update the indirect pointers
2098                  * to the blocks, we can't free them. */
2099                 if (err)
2100                         return;
2101         }
2102
2103         for (p = first; p < last; p++) {
2104                 nr = le32_to_cpu(*p);
2105                 if (nr) {
2106                         /* accumulate blocks to free if they're contiguous */
2107                         if (count == 0) {
2108                                 block_to_free = nr;
2109                                 block_to_free_p = p;
2110                                 count = 1;
2111                         } else if (nr == block_to_free + count) {
2112                                 count++;
2113                         } else {
2114                                 ext3_clear_blocks(handle, inode, this_bh,
2115                                                   block_to_free,
2116                                                   count, block_to_free_p, p);
2117                                 block_to_free = nr;
2118                                 block_to_free_p = p;
2119                                 count = 1;
2120                         }
2121                 }
2122         }
2123
2124         if (count > 0)
2125                 ext3_clear_blocks(handle, inode, this_bh, block_to_free,
2126                                   count, block_to_free_p, p);
2127
2128         if (this_bh) {
2129                 BUFFER_TRACE(this_bh, "call ext3_journal_dirty_metadata");
2130                 ext3_journal_dirty_metadata(handle, this_bh);
2131         }
2132 }
2133
2134 /**
2135  *      ext3_free_branches - free an array of branches
2136  *      @handle: JBD handle for this transaction
2137  *      @inode: inode we are dealing with
2138  *      @parent_bh: the buffer_head which contains *@first and *@last
2139  *      @first: array of block numbers
2140  *      @last:  pointer immediately past the end of array
2141  *      @depth: depth of the branches to free
2142  *
2143  *      We are freeing all blocks refered from these branches (numbers are
2144  *      stored as little-endian 32-bit) and updating @inode->i_blocks
2145  *      appropriately.
2146  */
2147 static void ext3_free_branches(handle_t *handle, struct inode *inode,
2148                                struct buffer_head *parent_bh,
2149                                __le32 *first, __le32 *last, int depth)
2150 {
2151         ext3_fsblk_t nr;
2152         __le32 *p;
2153
2154         if (is_handle_aborted(handle))
2155                 return;
2156
2157         if (depth--) {
2158                 struct buffer_head *bh;
2159                 int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
2160                 p = last;
2161                 while (--p >= first) {
2162                         nr = le32_to_cpu(*p);
2163                         if (!nr)
2164                                 continue;               /* A hole */
2165
2166                         /* Go read the buffer for the next level down */
2167                         bh = sb_bread(inode->i_sb, nr);
2168
2169                         /*
2170                          * A read failure? Report error and clear slot
2171                          * (should be rare).
2172                          */
2173                         if (!bh) {
2174                                 ext3_error(inode->i_sb, "ext3_free_branches",
2175                                            "Read failure, inode=%lu, block="E3FSBLK,
2176                                            inode->i_ino, nr);
2177                                 continue;
2178                         }
2179
2180                         /* This zaps the entire block.  Bottom up. */
2181                         BUFFER_TRACE(bh, "free child branches");
2182                         ext3_free_branches(handle, inode, bh,
2183                                            (__le32*)bh->b_data,
2184                                            (__le32*)bh->b_data + addr_per_block,
2185                                            depth);
2186
2187                         /*
2188                          * We've probably journalled the indirect block several
2189                          * times during the truncate.  But it's no longer
2190                          * needed and we now drop it from the transaction via
2191                          * journal_revoke().
2192                          *
2193                          * That's easy if it's exclusively part of this
2194                          * transaction.  But if it's part of the committing
2195                          * transaction then journal_forget() will simply
2196                          * brelse() it.  That means that if the underlying
2197                          * block is reallocated in ext3_get_block(),
2198                          * unmap_underlying_metadata() will find this block
2199                          * and will try to get rid of it.  damn, damn.
2200                          *
2201                          * If this block has already been committed to the
2202                          * journal, a revoke record will be written.  And
2203                          * revoke records must be emitted *before* clearing
2204                          * this block's bit in the bitmaps.
2205                          */
2206                         ext3_forget(handle, 1, inode, bh, bh->b_blocknr);
2207
2208                         /*
2209                          * Everything below this this pointer has been
2210                          * released.  Now let this top-of-subtree go.
2211                          *
2212                          * We want the freeing of this indirect block to be
2213                          * atomic in the journal with the updating of the
2214                          * bitmap block which owns it.  So make some room in
2215                          * the journal.
2216                          *
2217                          * We zero the parent pointer *after* freeing its
2218                          * pointee in the bitmaps, so if extend_transaction()
2219                          * for some reason fails to put the bitmap changes and
2220                          * the release into the same transaction, recovery
2221                          * will merely complain about releasing a free block,
2222                          * rather than leaking blocks.
2223                          */
2224                         if (is_handle_aborted(handle))
2225                                 return;
2226                         if (try_to_extend_transaction(handle, inode)) {
2227                                 ext3_mark_inode_dirty(handle, inode);
2228                                 ext3_journal_test_restart(handle, inode);
2229                         }
2230
2231                         ext3_free_blocks(handle, inode, nr, 1);
2232
2233                         if (parent_bh) {
2234                                 /*
2235                                  * The block which we have just freed is
2236                                  * pointed to by an indirect block: journal it
2237                                  */
2238                                 BUFFER_TRACE(parent_bh, "get_write_access");
2239                                 if (!ext3_journal_get_write_access(handle,
2240                                                                    parent_bh)){
2241                                         *p = 0;
2242                                         BUFFER_TRACE(parent_bh,
2243                                         "call ext3_journal_dirty_metadata");
2244                                         ext3_journal_dirty_metadata(handle,
2245                                                                     parent_bh);
2246                                 }
2247                         }
2248                 }
2249         } else {
2250                 /* We have reached the bottom of the tree. */
2251                 BUFFER_TRACE(parent_bh, "free data blocks");
2252                 ext3_free_data(handle, inode, parent_bh, first, last);
2253         }
2254 }
2255
2256 int ext3_can_truncate(struct inode *inode)
2257 {
2258         if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
2259                 return 0;
2260         if (S_ISREG(inode->i_mode))
2261                 return 1;
2262         if (S_ISDIR(inode->i_mode))
2263                 return 1;
2264         if (S_ISLNK(inode->i_mode))
2265                 return !ext3_inode_is_fast_symlink(inode);
2266         return 0;
2267 }
2268
2269 /*
2270  * ext3_truncate()
2271  *
2272  * We block out ext3_get_block() block instantiations across the entire
2273  * transaction, and VFS/VM ensures that ext3_truncate() cannot run
2274  * simultaneously on behalf of the same inode.
2275  *
2276  * As we work through the truncate and commmit bits of it to the journal there
2277  * is one core, guiding principle: the file's tree must always be consistent on
2278  * disk.  We must be able to restart the truncate after a crash.
2279  *
2280  * The file's tree may be transiently inconsistent in memory (although it
2281  * probably isn't), but whenever we close off and commit a journal transaction,
2282  * the contents of (the filesystem + the journal) must be consistent and
2283  * restartable.  It's pretty simple, really: bottom up, right to left (although
2284  * left-to-right works OK too).
2285  *
2286  * Note that at recovery time, journal replay occurs *before* the restart of
2287  * truncate against the orphan inode list.
2288  *
2289  * The committed inode has the new, desired i_size (which is the same as
2290  * i_disksize in this case).  After a crash, ext3_orphan_cleanup() will see
2291  * that this inode's truncate did not complete and it will again call
2292  * ext3_truncate() to have another go.  So there will be instantiated blocks
2293  * to the right of the truncation point in a crashed ext3 filesystem.  But
2294  * that's fine - as long as they are linked from the inode, the post-crash
2295  * ext3_truncate() run will find them and release them.
2296  */
2297 void ext3_truncate(struct inode *inode)
2298 {
2299         handle_t *handle;
2300         struct ext3_inode_info *ei = EXT3_I(inode);
2301         __le32 *i_data = ei->i_data;
2302         int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
2303         struct address_space *mapping = inode->i_mapping;
2304         int offsets[4];
2305         Indirect chain[4];
2306         Indirect *partial;
2307         __le32 nr = 0;
2308         int n;
2309         long last_block;
2310         unsigned blocksize = inode->i_sb->s_blocksize;
2311         struct page *page;
2312
2313         if (!ext3_can_truncate(inode))
2314                 return;
2315
2316         /*
2317          * We have to lock the EOF page here, because lock_page() nests
2318          * outside journal_start().
2319          */
2320         if ((inode->i_size & (blocksize - 1)) == 0) {
2321                 /* Block boundary? Nothing to do */
2322                 page = NULL;
2323         } else {
2324                 page = grab_cache_page(mapping,
2325                                 inode->i_size >> PAGE_CACHE_SHIFT);
2326                 if (!page)
2327                         return;
2328         }
2329
2330         handle = start_transaction(inode);
2331         if (IS_ERR(handle)) {
2332                 if (page) {
2333                         clear_highpage(page);
2334                         flush_dcache_page(page);
2335                         unlock_page(page);
2336                         page_cache_release(page);
2337                 }
2338                 return;         /* AKPM: return what? */
2339         }
2340
2341         last_block = (inode->i_size + blocksize-1)
2342                                         >> EXT3_BLOCK_SIZE_BITS(inode->i_sb);
2343
2344         if (page)
2345                 ext3_block_truncate_page(handle, page, mapping, inode->i_size);
2346
2347         n = ext3_block_to_path(inode, last_block, offsets, NULL);
2348         if (n == 0)
2349                 goto out_stop;  /* error */
2350
2351         /*
2352          * OK.  This truncate is going to happen.  We add the inode to the
2353          * orphan list, so that if this truncate spans multiple transactions,
2354          * and we crash, we will resume the truncate when the filesystem
2355          * recovers.  It also marks the inode dirty, to catch the new size.
2356          *
2357          * Implication: the file must always be in a sane, consistent
2358          * truncatable state while each transaction commits.
2359          */
2360         if (ext3_orphan_add(handle, inode))
2361                 goto out_stop;
2362
2363         /*
2364          * The orphan list entry will now protect us from any crash which
2365          * occurs before the truncate completes, so it is now safe to propagate
2366          * the new, shorter inode size (held for now in i_size) into the
2367          * on-disk inode. We do this via i_disksize, which is the value which
2368          * ext3 *really* writes onto the disk inode.
2369          */
2370         ei->i_disksize = inode->i_size;
2371
2372         /*
2373          * From here we block out all ext3_get_block() callers who want to
2374          * modify the block allocation tree.
2375          */
2376         mutex_lock(&ei->truncate_mutex);
2377
2378         if (n == 1) {           /* direct blocks */
2379                 ext3_free_data(handle, inode, NULL, i_data+offsets[0],
2380                                i_data + EXT3_NDIR_BLOCKS);
2381                 goto do_indirects;
2382         }
2383
2384         partial = ext3_find_shared(inode, n, offsets, chain, &nr);
2385         /* Kill the top of shared branch (not detached) */
2386         if (nr) {
2387                 if (partial == chain) {
2388                         /* Shared branch grows from the inode */
2389                         ext3_free_branches(handle, inode, NULL,
2390                                            &nr, &nr+1, (chain+n-1) - partial);
2391                         *partial->p = 0;
2392                         /*
2393                          * We mark the inode dirty prior to restart,
2394                          * and prior to stop.  No need for it here.
2395                          */
2396                 } else {
2397                         /* Shared branch grows from an indirect block */
2398                         BUFFER_TRACE(partial->bh, "get_write_access");
2399                         ext3_free_branches(handle, inode, partial->bh,
2400                                         partial->p,
2401                                         partial->p+1, (chain+n-1) - partial);
2402                 }
2403         }
2404         /* Clear the ends of indirect blocks on the shared branch */
2405         while (partial > chain) {
2406                 ext3_free_branches(handle, inode, partial->bh, partial->p + 1,
2407                                    (__le32*)partial->bh->b_data+addr_per_block,
2408                                    (chain+n-1) - partial);
2409                 BUFFER_TRACE(partial->bh, "call brelse");
2410                 brelse (partial->bh);
2411                 partial--;
2412         }
2413 do_indirects:
2414         /* Kill the remaining (whole) subtrees */
2415         switch (offsets[0]) {
2416         default:
2417                 nr = i_data[EXT3_IND_BLOCK];
2418                 if (nr) {
2419                         ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
2420                         i_data[EXT3_IND_BLOCK] = 0;
2421                 }
2422         case EXT3_IND_BLOCK:
2423                 nr = i_data[EXT3_DIND_BLOCK];
2424                 if (nr) {
2425                         ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
2426                         i_data[EXT3_DIND_BLOCK] = 0;
2427                 }
2428         case EXT3_DIND_BLOCK:
2429                 nr = i_data[EXT3_TIND_BLOCK];
2430                 if (nr) {
2431                         ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
2432                         i_data[EXT3_TIND_BLOCK] = 0;
2433                 }
2434         case EXT3_TIND_BLOCK:
2435                 ;
2436         }
2437
2438         ext3_discard_reservation(inode);
2439
2440         mutex_unlock(&ei->truncate_mutex);
2441         inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
2442         ext3_mark_inode_dirty(handle, inode);
2443
2444         /*
2445          * In a multi-transaction truncate, we only make the final transaction
2446          * synchronous
2447          */
2448         if (IS_SYNC(inode))
2449                 handle->h_sync = 1;
2450 out_stop:
2451         /*
2452          * If this was a simple ftruncate(), and the file will remain alive
2453          * then we need to clear up the orphan record which we created above.
2454          * However, if this was a real unlink then we were called by
2455          * ext3_delete_inode(), and we allow that function to clean up the
2456          * orphan info for us.
2457          */
2458         if (inode->i_nlink)
2459                 ext3_orphan_del(handle, inode);
2460
2461         ext3_journal_stop(handle);
2462 }
2463
2464 static ext3_fsblk_t ext3_get_inode_block(struct super_block *sb,
2465                 unsigned long ino, struct ext3_iloc *iloc)
2466 {
2467         unsigned long block_group;
2468         unsigned long offset;
2469         ext3_fsblk_t block;
2470         struct ext3_group_desc *gdp;
2471
2472         if (!ext3_valid_inum(sb, ino)) {
2473                 /*
2474                  * This error is already checked for in namei.c unless we are
2475                  * looking at an NFS filehandle, in which case no error
2476                  * report is needed
2477                  */
2478                 return 0;
2479         }
2480
2481         block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
2482         gdp = ext3_get_group_desc(sb, block_group, NULL);
2483         if (!gdp)
2484                 return 0;
2485         /*
2486          * Figure out the offset within the block group inode table
2487          */
2488         offset = ((ino - 1) % EXT3_INODES_PER_GROUP(sb)) *
2489                 EXT3_INODE_SIZE(sb);
2490         block = le32_to_cpu(gdp->bg_inode_table) +
2491                 (offset >> EXT3_BLOCK_SIZE_BITS(sb));
2492
2493         iloc->block_group = block_group;
2494         iloc->offset = offset & (EXT3_BLOCK_SIZE(sb) - 1);
2495         return block;
2496 }
2497
2498 /*
2499  * ext3_get_inode_loc returns with an extra refcount against the inode's
2500  * underlying buffer_head on success. If 'in_mem' is true, we have all
2501  * data in memory that is needed to recreate the on-disk version of this
2502  * inode.
2503  */
2504 static int __ext3_get_inode_loc(struct inode *inode,
2505                                 struct ext3_iloc *iloc, int in_mem)
2506 {
2507         ext3_fsblk_t block;
2508         struct buffer_head *bh;
2509
2510         block = ext3_get_inode_block(inode->i_sb, inode->i_ino, iloc);
2511         if (!block)
2512                 return -EIO;
2513
2514         bh = sb_getblk(inode->i_sb, block);
2515         if (!bh) {
2516                 ext3_error (inode->i_sb, "ext3_get_inode_loc",
2517                                 "unable to read inode block - "
2518                                 "inode=%lu, block="E3FSBLK,
2519                                  inode->i_ino, block);
2520                 return -EIO;
2521         }
2522         if (!buffer_uptodate(bh)) {
2523                 lock_buffer(bh);
2524
2525                 /*
2526                  * If the buffer has the write error flag, we have failed
2527                  * to write out another inode in the same block.  In this
2528                  * case, we don't have to read the block because we may
2529                  * read the old inode data successfully.
2530                  */
2531                 if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
2532                         set_buffer_uptodate(bh);
2533
2534                 if (buffer_uptodate(bh)) {
2535                         /* someone brought it uptodate while we waited */
2536                         unlock_buffer(bh);
2537                         goto has_buffer;
2538                 }
2539
2540                 /*
2541                  * If we have all information of the inode in memory and this
2542                  * is the only valid inode in the block, we need not read the
2543                  * block.
2544                  */
2545                 if (in_mem) {
2546                         struct buffer_head *bitmap_bh;
2547                         struct ext3_group_desc *desc;
2548                         int inodes_per_buffer;
2549                         int inode_offset, i;
2550                         int block_group;
2551                         int start;
2552
2553                         block_group = (inode->i_ino - 1) /
2554                                         EXT3_INODES_PER_GROUP(inode->i_sb);
2555                         inodes_per_buffer = bh->b_size /
2556                                 EXT3_INODE_SIZE(inode->i_sb);
2557                         inode_offset = ((inode->i_ino - 1) %
2558                                         EXT3_INODES_PER_GROUP(inode->i_sb));
2559                         start = inode_offset & ~(inodes_per_buffer - 1);
2560
2561                         /* Is the inode bitmap in cache? */
2562                         desc = ext3_get_group_desc(inode->i_sb,
2563                                                 block_group, NULL);
2564                         if (!desc)
2565                                 goto make_io;
2566
2567                         bitmap_bh = sb_getblk(inode->i_sb,
2568                                         le32_to_cpu(desc->bg_inode_bitmap));
2569                         if (!bitmap_bh)
2570                                 goto make_io;
2571
2572                         /*
2573                          * If the inode bitmap isn't in cache then the
2574                          * optimisation may end up performing two reads instead
2575                          * of one, so skip it.
2576                          */
2577                         if (!buffer_uptodate(bitmap_bh)) {
2578                                 brelse(bitmap_bh);
2579                                 goto make_io;
2580                         }
2581                         for (i = start; i < start + inodes_per_buffer; i++) {
2582                                 if (i == inode_offset)
2583                                         continue;
2584                                 if (ext3_test_bit(i, bitmap_bh->b_data))
2585                                         break;
2586                         }
2587                         brelse(bitmap_bh);
2588                         if (i == start + inodes_per_buffer) {
2589                                 /* all other inodes are free, so skip I/O */
2590                                 memset(bh->b_data, 0, bh->b_size);
2591                                 set_buffer_uptodate(bh);
2592                                 unlock_buffer(bh);
2593                                 goto has_buffer;
2594                         }
2595                 }
2596
2597 make_io:
2598                 /*
2599                  * There are other valid inodes in the buffer, this inode
2600                  * has in-inode xattrs, or we don't have this inode in memory.
2601                  * Read the block from disk.
2602                  */
2603                 get_bh(bh);
2604                 bh->b_end_io = end_buffer_read_sync;
2605                 submit_bh(READ_META, bh);
2606                 wait_on_buffer(bh);
2607                 if (!buffer_uptodate(bh)) {
2608                         ext3_error(inode->i_sb, "ext3_get_inode_loc",
2609                                         "unable to read inode block - "
2610                                         "inode=%lu, block="E3FSBLK,
2611                                         inode->i_ino, block);
2612                         brelse(bh);
2613                         return -EIO;
2614                 }
2615         }
2616 has_buffer:
2617         iloc->bh = bh;
2618         return 0;
2619 }
2620
2621 int ext3_get_inode_loc(struct inode *inode, struct ext3_iloc *iloc)
2622 {
2623         /* We have all inode data except xattrs in memory here. */
2624         return __ext3_get_inode_loc(inode, iloc,
2625                 !(EXT3_I(inode)->i_state & EXT3_STATE_XATTR));
2626 }
2627
2628 void ext3_set_inode_flags(struct inode *inode)
2629 {
2630         unsigned int flags = EXT3_I(inode)->i_flags;
2631
2632         inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
2633         if (flags & EXT3_SYNC_FL)
2634                 inode->i_flags |= S_SYNC;
2635         if (flags & EXT3_APPEND_FL)
2636                 inode->i_flags |= S_APPEND;
2637         if (flags & EXT3_IMMUTABLE_FL)
2638                 inode->i_flags |= S_IMMUTABLE;
2639         if (flags & EXT3_NOATIME_FL)
2640                 inode->i_flags |= S_NOATIME;
2641         if (flags & EXT3_DIRSYNC_FL)
2642                 inode->i_flags |= S_DIRSYNC;
2643 }
2644
2645 /* Propagate flags from i_flags to EXT3_I(inode)->i_flags */
2646 void ext3_get_inode_flags(struct ext3_inode_info *ei)
2647 {
2648         unsigned int flags = ei->vfs_inode.i_flags;
2649
2650         ei->i_flags &= ~(EXT3_SYNC_FL|EXT3_APPEND_FL|
2651                         EXT3_IMMUTABLE_FL|EXT3_NOATIME_FL|EXT3_DIRSYNC_FL);
2652         if (flags & S_SYNC)
2653                 ei->i_flags |= EXT3_SYNC_FL;
2654         if (flags & S_APPEND)
2655                 ei->i_flags |= EXT3_APPEND_FL;
2656         if (flags & S_IMMUTABLE)
2657                 ei->i_flags |= EXT3_IMMUTABLE_FL;
2658         if (flags & S_NOATIME)
2659                 ei->i_flags |= EXT3_NOATIME_FL;
2660         if (flags & S_DIRSYNC)
2661                 ei->i_flags |= EXT3_DIRSYNC_FL;
2662 }
2663
2664 struct inode *ext3_iget(struct super_block *sb, unsigned long ino)
2665 {
2666         struct ext3_iloc iloc;
2667         struct ext3_inode *raw_inode;
2668         struct ext3_inode_info *ei;
2669         struct buffer_head *bh;
2670         struct inode *inode;
2671         long ret;
2672         int block;
2673
2674         inode = iget_locked(sb, ino);
2675         if (!inode)
2676                 return ERR_PTR(-ENOMEM);
2677         if (!(inode->i_state & I_NEW))
2678                 return inode;
2679
2680         ei = EXT3_I(inode);
2681 #ifdef CONFIG_EXT3_FS_POSIX_ACL
2682         ei->i_acl = EXT3_ACL_NOT_CACHED;
2683         ei->i_default_acl = EXT3_ACL_NOT_CACHED;
2684 #endif
2685         ei->i_block_alloc_info = NULL;
2686
2687         ret = __ext3_get_inode_loc(inode, &iloc, 0);
2688         if (ret < 0)
2689                 goto bad_inode;
2690         bh = iloc.bh;
2691         raw_inode = ext3_raw_inode(&iloc);
2692         inode->i_mode = le16_to_cpu(raw_inode->i_mode);
2693         inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
2694         inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
2695         if(!(test_opt (inode->i_sb, NO_UID32))) {
2696                 inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
2697                 inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
2698         }
2699         inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
2700         inode->i_size = le32_to_cpu(raw_inode->i_size);
2701         inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
2702         inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
2703         inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
2704         inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = inode->i_mtime.tv_nsec = 0;
2705
2706         ei->i_state = 0;
2707         ei->i_dir_start_lookup = 0;
2708         ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
2709         /* We now have enough fields to check if the inode was active or not.
2710          * This is needed because nfsd might try to access dead inodes
2711          * the test is that same one that e2fsck uses
2712          * NeilBrown 1999oct15
2713          */
2714         if (inode->i_nlink == 0) {
2715                 if (inode->i_mode == 0 ||
2716                     !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ORPHAN_FS)) {
2717                         /* this inode is deleted */
2718                         brelse (bh);
2719                         ret = -ESTALE;
2720                         goto bad_inode;
2721                 }
2722                 /* The only unlinked inodes we let through here have
2723                  * valid i_mode and are being read by the orphan
2724                  * recovery code: that's fine, we're about to complete
2725                  * the process of deleting those. */
2726         }
2727         inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
2728         ei->i_flags = le32_to_cpu(raw_inode->i_flags);
2729 #ifdef EXT3_FRAGMENTS
2730         ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
2731         ei->i_frag_no = raw_inode->i_frag;
2732         ei->i_frag_size = raw_inode->i_fsize;
2733 #endif
2734         ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
2735         if (!S_ISREG(inode->i_mode)) {
2736                 ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
2737         } else {
2738                 inode->i_size |=
2739                         ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
2740         }
2741         ei->i_disksize = inode->i_size;
2742         inode->i_generation = le32_to_cpu(raw_inode->i_generation);
2743         ei->i_block_group = iloc.block_group;
2744         /*
2745          * NOTE! The in-memory inode i_data array is in little-endian order
2746          * even on big-endian machines: we do NOT byteswap the block numbers!
2747          */
2748         for (block = 0; block < EXT3_N_BLOCKS; block++)
2749                 ei->i_data[block] = raw_inode->i_block[block];
2750         INIT_LIST_HEAD(&ei->i_orphan);
2751
2752         if (inode->i_ino >= EXT3_FIRST_INO(inode->i_sb) + 1 &&
2753             EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) {
2754                 /*
2755                  * When mke2fs creates big inodes it does not zero out
2756                  * the unused bytes above EXT3_GOOD_OLD_INODE_SIZE,
2757                  * so ignore those first few inodes.
2758                  */
2759                 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
2760                 if (EXT3_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
2761                     EXT3_INODE_SIZE(inode->i_sb)) {
2762                         brelse (bh);
2763                         ret = -EIO;
2764                         goto bad_inode;
2765                 }
2766                 if (ei->i_extra_isize == 0) {
2767                         /* The extra space is currently unused. Use it. */
2768                         ei->i_extra_isize = sizeof(struct ext3_inode) -
2769                                             EXT3_GOOD_OLD_INODE_SIZE;
2770                 } else {
2771                         __le32 *magic = (void *)raw_inode +
2772                                         EXT3_GOOD_OLD_INODE_SIZE +
2773                                         ei->i_extra_isize;
2774                         if (*magic == cpu_to_le32(EXT3_XATTR_MAGIC))
2775                                  ei->i_state |= EXT3_STATE_XATTR;
2776                 }
2777         } else
2778                 ei->i_extra_isize = 0;
2779
2780         if (S_ISREG(inode->i_mode)) {
2781                 inode->i_op = &ext3_file_inode_operations;
2782                 inode->i_fop = &ext3_file_operations;
2783                 ext3_set_aops(inode);
2784         } else if (S_ISDIR(inode->i_mode)) {
2785                 inode->i_op = &ext3_dir_inode_operations;
2786                 inode->i_fop = &ext3_dir_operations;
2787         } else if (S_ISLNK(inode->i_mode)) {
2788                 if (ext3_inode_is_fast_symlink(inode))
2789                         inode->i_op = &ext3_fast_symlink_inode_operations;
2790                 else {
2791                         inode->i_op = &ext3_symlink_inode_operations;
2792                         ext3_set_aops(inode);
2793                 }
2794         } else {
2795                 inode->i_op = &ext3_special_inode_operations;
2796                 if (raw_inode->i_block[0])
2797                         init_special_inode(inode, inode->i_mode,
2798                            old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
2799                 else
2800                         init_special_inode(inode, inode->i_mode,
2801                            new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
2802         }
2803         brelse (iloc.bh);
2804         ext3_set_inode_flags(inode);
2805         unlock_new_inode(inode);
2806         return inode;
2807
2808 bad_inode:
2809         iget_failed(inode);
2810         return ERR_PTR(ret);
2811 }
2812
2813 /*
2814  * Post the struct inode info into an on-disk inode location in the
2815  * buffer-cache.  This gobbles the caller's reference to the
2816  * buffer_head in the inode location struct.
2817  *
2818  * The caller must have write access to iloc->bh.
2819  */
2820 static int ext3_do_update_inode(handle_t *handle,
2821                                 struct inode *inode,
2822                                 struct ext3_iloc *iloc)
2823 {
2824         struct ext3_inode *raw_inode = ext3_raw_inode(iloc);
2825         struct ext3_inode_info *ei = EXT3_I(inode);
2826         struct buffer_head *bh = iloc->bh;
2827         int err = 0, rc, block;
2828
2829         /* For fields not not tracking in the in-memory inode,
2830          * initialise them to zero for new inodes. */
2831         if (ei->i_state & EXT3_STATE_NEW)
2832                 memset(raw_inode, 0, EXT3_SB(inode->i_sb)->s_inode_size);
2833
2834         ext3_get_inode_flags(ei);
2835         raw_inode->i_mode = cpu_to_le16(inode->i_mode);
2836         if(!(test_opt(inode->i_sb, NO_UID32))) {
2837                 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
2838                 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid));
2839 /*
2840  * Fix up interoperability with old kernels. Otherwise, old inodes get
2841  * re-used with the upper 16 bits of the uid/gid intact
2842  */
2843                 if(!ei->i_dtime) {
2844                         raw_inode->i_uid_high =
2845                                 cpu_to_le16(high_16_bits(inode->i_uid));
2846                         raw_inode->i_gid_high =
2847                                 cpu_to_le16(high_16_bits(inode->i_gid));
2848                 } else {
2849                         raw_inode->i_uid_high = 0;
2850                         raw_inode->i_gid_high = 0;
2851                 }
2852         } else {
2853                 raw_inode->i_uid_low =
2854                         cpu_to_le16(fs_high2lowuid(inode->i_uid));
2855                 raw_inode->i_gid_low =
2856                         cpu_to_le16(fs_high2lowgid(inode->i_gid));
2857                 raw_inode->i_uid_high = 0;
2858                 raw_inode->i_gid_high = 0;
2859         }
2860         raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
2861         raw_inode->i_size = cpu_to_le32(ei->i_disksize);
2862         raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
2863         raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
2864         raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
2865         raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
2866         raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
2867         raw_inode->i_flags = cpu_to_le32(ei->i_flags);
2868 #ifdef EXT3_FRAGMENTS
2869         raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
2870         raw_inode->i_frag = ei->i_frag_no;
2871         raw_inode->i_fsize = ei->i_frag_size;
2872 #endif
2873         raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
2874         if (!S_ISREG(inode->i_mode)) {
2875                 raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
2876         } else {
2877                 raw_inode->i_size_high =
2878                         cpu_to_le32(ei->i_disksize >> 32);
2879                 if (ei->i_disksize > 0x7fffffffULL) {
2880                         struct super_block *sb = inode->i_sb;
2881                         if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
2882                                         EXT3_FEATURE_RO_COMPAT_LARGE_FILE) ||
2883                             EXT3_SB(sb)->s_es->s_rev_level ==
2884                                         cpu_to_le32(EXT3_GOOD_OLD_REV)) {
2885                                /* If this is the first large file
2886                                 * created, add a flag to the superblock.
2887                                 */
2888                                 err = ext3_journal_get_write_access(handle,
2889                                                 EXT3_SB(sb)->s_sbh);
2890                                 if (err)
2891                                         goto out_brelse;
2892                                 ext3_update_dynamic_rev(sb);
2893                                 EXT3_SET_RO_COMPAT_FEATURE(sb,
2894                                         EXT3_FEATURE_RO_COMPAT_LARGE_FILE);
2895                                 sb->s_dirt = 1;
2896                                 handle->h_sync = 1;
2897                                 err = ext3_journal_dirty_metadata(handle,
2898                                                 EXT3_SB(sb)->s_sbh);
2899                         }
2900                 }
2901         }
2902         raw_inode->i_generation = cpu_to_le32(inode->i_generation);
2903         if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
2904                 if (old_valid_dev(inode->i_rdev)) {
2905                         raw_inode->i_block[0] =
2906                                 cpu_to_le32(old_encode_dev(inode->i_rdev));
2907                         raw_inode->i_block[1] = 0;
2908                 } else {
2909                         raw_inode->i_block[0] = 0;
2910                         raw_inode->i_block[1] =
2911                                 cpu_to_le32(new_encode_dev(inode->i_rdev));
2912                         raw_inode->i_block[2] = 0;
2913                 }
2914         } else for (block = 0; block < EXT3_N_BLOCKS; block++)
2915                 raw_inode->i_block[block] = ei->i_data[block];
2916
2917         if (ei->i_extra_isize)
2918                 raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
2919
2920         BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
2921         rc = ext3_journal_dirty_metadata(handle, bh);
2922         if (!err)
2923                 err = rc;
2924         ei->i_state &= ~EXT3_STATE_NEW;
2925
2926 out_brelse:
2927         brelse (bh);
2928         ext3_std_error(inode->i_sb, err);
2929         return err;
2930 }
2931
2932 /*
2933  * ext3_write_inode()
2934  *
2935  * We are called from a few places:
2936  *
2937  * - Within generic_file_write() for O_SYNC files.
2938  *   Here, there will be no transaction running. We wait for any running
2939  *   trasnaction to commit.
2940  *
2941  * - Within sys_sync(), kupdate and such.
2942  *   We wait on commit, if tol to.
2943  *
2944  * - Within prune_icache() (PF_MEMALLOC == true)
2945  *   Here we simply return.  We can't afford to block kswapd on the
2946  *   journal commit.
2947  *
2948  * In all cases it is actually safe for us to return without doing anything,
2949  * because the inode has been copied into a raw inode buffer in
2950  * ext3_mark_inode_dirty().  This is a correctness thing for O_SYNC and for
2951  * knfsd.
2952  *
2953  * Note that we are absolutely dependent upon all inode dirtiers doing the
2954  * right thing: they *must* call mark_inode_dirty() after dirtying info in
2955  * which we are interested.
2956  *
2957  * It would be a bug for them to not do this.  The code:
2958  *
2959  *      mark_inode_dirty(inode)
2960  *      stuff();
2961  *      inode->i_size = expr;
2962  *
2963  * is in error because a kswapd-driven write_inode() could occur while
2964  * `stuff()' is running, and the new i_size will be lost.  Plus the inode
2965  * will no longer be on the superblock's dirty inode list.
2966  */
2967 int ext3_write_inode(struct inode *inode, int wait)
2968 {
2969         if (current->flags & PF_MEMALLOC)
2970                 return 0;
2971
2972         if (ext3_journal_current_handle()) {
2973                 jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
2974                 dump_stack();
2975                 return -EIO;
2976         }
2977
2978         if (!wait)
2979                 return 0;
2980
2981         return ext3_force_commit(inode->i_sb);
2982 }
2983
2984 /*
2985  * ext3_setattr()
2986  *
2987  * Called from notify_change.
2988  *
2989  * We want to trap VFS attempts to truncate the file as soon as
2990  * possible.  In particular, we want to make sure that when the VFS
2991  * shrinks i_size, we put the inode on the orphan list and modify
2992  * i_disksize immediately, so that during the subsequent flushing of
2993  * dirty pages and freeing of disk blocks, we can guarantee that any
2994  * commit will leave the blocks being flushed in an unused state on
2995  * disk.  (On recovery, the inode will get truncated and the blocks will
2996  * be freed, so we have a strong guarantee that no future commit will
2997  * leave these blocks visible to the user.)
2998  *
2999  * Called with inode->sem down.
3000  */
3001 int ext3_setattr(struct dentry *dentry, struct iattr *attr)
3002 {
3003         struct inode *inode = dentry->d_inode;
3004         int error, rc = 0;
3005         const unsigned int ia_valid = attr->ia_valid;
3006
3007         error = inode_change_ok(inode, attr);
3008         if (error)
3009                 return error;
3010
3011         if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
3012                 (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) {
3013                 handle_t *handle;
3014
3015                 /* (user+group)*(old+new) structure, inode write (sb,
3016                  * inode block, ? - but truncate inode update has it) */
3017                 handle = ext3_journal_start(inode, 2*(EXT3_QUOTA_INIT_BLOCKS(inode->i_sb)+
3018                                         EXT3_QUOTA_DEL_BLOCKS(inode->i_sb))+3);
3019                 if (IS_ERR(handle)) {
3020                         error = PTR_ERR(handle);
3021                         goto err_out;
3022                 }
3023                 error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
3024                 if (error) {
3025                         ext3_journal_stop(handle);
3026                         return error;
3027                 }
3028                 /* Update corresponding info in inode so that everything is in
3029                  * one transaction */
3030                 if (attr->ia_valid & ATTR_UID)
3031                         inode->i_uid = attr->ia_uid;
3032                 if (attr->ia_valid & ATTR_GID)
3033                         inode->i_gid = attr->ia_gid;
3034                 error = ext3_mark_inode_dirty(handle, inode);
3035                 ext3_journal_stop(handle);
3036         }
3037
3038         if (S_ISREG(inode->i_mode) &&
3039             attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
3040                 handle_t *handle;
3041
3042                 handle = ext3_journal_start(inode, 3);
3043                 if (IS_ERR(handle)) {
3044                         error = PTR_ERR(handle);
3045                         goto err_out;
3046                 }
3047
3048                 error = ext3_orphan_add(handle, inode);
3049                 EXT3_I(inode)->i_disksize = attr->ia_size;
3050                 rc = ext3_mark_inode_dirty(handle, inode);
3051                 if (!error)
3052                         error = rc;
3053                 ext3_journal_stop(handle);
3054         }
3055
3056         rc = inode_setattr(inode, attr);
3057
3058         /* If inode_setattr's call to ext3_truncate failed to get a
3059          * transaction handle at all, we need to clean up the in-core
3060          * orphan list manually. */
3061         if (inode->i_nlink)
3062                 ext3_orphan_del(NULL, inode);
3063
3064         if (!rc && (ia_valid & ATTR_MODE))
3065                 rc = ext3_acl_chmod(inode);
3066
3067 err_out:
3068         ext3_std_error(inode->i_sb, error);
3069         if (!error)
3070                 error = rc;
3071         return error;
3072 }
3073
3074
3075 /*
3076  * How many blocks doth make a writepage()?
3077  *
3078  * With N blocks per page, it may be:
3079  * N data blocks
3080  * 2 indirect block
3081  * 2 dindirect
3082  * 1 tindirect
3083  * N+5 bitmap blocks (from the above)
3084  * N+5 group descriptor summary blocks
3085  * 1 inode block
3086  * 1 superblock.
3087  * 2 * EXT3_SINGLEDATA_TRANS_BLOCKS for the quote files
3088  *
3089  * 3 * (N + 5) + 2 + 2 * EXT3_SINGLEDATA_TRANS_BLOCKS
3090  *
3091  * With ordered or writeback data it's the same, less the N data blocks.
3092  *
3093  * If the inode's direct blocks can hold an integral number of pages then a
3094  * page cannot straddle two indirect blocks, and we can only touch one indirect
3095  * and dindirect block, and the "5" above becomes "3".
3096  *
3097  * This still overestimates under most circumstances.  If we were to pass the
3098  * start and end offsets in here as well we could do block_to_path() on each
3099  * block and work out the exact number of indirects which are touched.  Pah.
3100  */
3101
3102 static int ext3_writepage_trans_blocks(struct inode *inode)
3103 {
3104         int bpp = ext3_journal_blocks_per_page(inode);
3105         int indirects = (EXT3_NDIR_BLOCKS % bpp) ? 5 : 3;
3106         int ret;
3107
3108         if (ext3_should_journal_data(inode))
3109                 ret = 3 * (bpp + indirects) + 2;
3110         else
3111                 ret = 2 * (bpp + indirects) + 2;
3112
3113 #ifdef CONFIG_QUOTA
3114         /* We know that structure was already allocated during DQUOT_INIT so
3115          * we will be updating only the data blocks + inodes */
3116         ret += 2*EXT3_QUOTA_TRANS_BLOCKS(inode->i_sb);
3117 #endif
3118
3119         return ret;
3120 }
3121
3122 /*
3123  * The caller must have previously called ext3_reserve_inode_write().
3124  * Give this, we know that the caller already has write access to iloc->bh.
3125  */
3126 int ext3_mark_iloc_dirty(handle_t *handle,
3127                 struct inode *inode, struct ext3_iloc *iloc)
3128 {
3129         int err = 0;
3130
3131         /* the do_update_inode consumes one bh->b_count */
3132         get_bh(iloc->bh);
3133
3134         /* ext3_do_update_inode() does journal_dirty_metadata */
3135         err = ext3_do_update_inode(handle, inode, iloc);
3136         put_bh(iloc->bh);
3137         return err;
3138 }
3139
3140 /*
3141  * On success, We end up with an outstanding reference count against
3142  * iloc->bh.  This _must_ be cleaned up later.
3143  */
3144
3145 int
3146 ext3_reserve_inode_write(handle_t *handle, struct inode *inode,
3147                          struct ext3_iloc *iloc)
3148 {
3149         int err = 0;
3150         if (handle) {
3151                 err = ext3_get_inode_loc(inode, iloc);
3152                 if (!err) {
3153                         BUFFER_TRACE(iloc->bh, "get_write_access");
3154                         err = ext3_journal_get_write_access(handle, iloc->bh);
3155                         if (err) {
3156                                 brelse(iloc->bh);
3157                                 iloc->bh = NULL;
3158                         }
3159                 }
3160         }
3161         ext3_std_error(inode->i_sb, err);
3162         return err;
3163 }
3164
3165 /*
3166  * What we do here is to mark the in-core inode as clean with respect to inode
3167  * dirtiness (it may still be data-dirty).
3168  * This means that the in-core inode may be reaped by prune_icache
3169  * without having to perform any I/O.  This is a very good thing,
3170  * because *any* task may call prune_icache - even ones which
3171  * have a transaction open against a different journal.
3172  *
3173  * Is this cheating?  Not really.  Sure, we haven't written the
3174  * inode out, but prune_icache isn't a user-visible syncing function.
3175  * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
3176  * we start and wait on commits.
3177  *
3178  * Is this efficient/effective?  Well, we're being nice to the system
3179  * by cleaning up our inodes proactively so they can be reaped
3180  * without I/O.  But we are potentially leaving up to five seconds'
3181  * worth of inodes floating about which prune_icache wants us to
3182  * write out.  One way to fix that would be to get prune_icache()
3183  * to do a write_super() to free up some memory.  It has the desired
3184  * effect.
3185  */
3186 int ext3_mark_inode_dirty(handle_t *handle, struct inode *inode)
3187 {
3188         struct ext3_iloc iloc;
3189         int err;
3190
3191         might_sleep();
3192         err = ext3_reserve_inode_write(handle, inode, &iloc);
3193         if (!err)
3194                 err = ext3_mark_iloc_dirty(handle, inode, &iloc);
3195         return err;
3196 }
3197
3198 /*
3199  * ext3_dirty_inode() is called from __mark_inode_dirty()
3200  *
3201  * We're really interested in the case where a file is being extended.
3202  * i_size has been changed by generic_commit_write() and we thus need
3203  * to include the updated inode in the current transaction.
3204  *
3205  * Also, DQUOT_ALLOC_SPACE() will always dirty the inode when blocks
3206  * are allocated to the file.
3207  *
3208  * If the inode is marked synchronous, we don't honour that here - doing
3209  * so would cause a commit on atime updates, which we don't bother doing.
3210  * We handle synchronous inodes at the highest possible level.
3211  */
3212 void ext3_dirty_inode(struct inode *inode)
3213 {
3214         handle_t *current_handle = ext3_journal_current_handle();
3215         handle_t *handle;
3216
3217         handle = ext3_journal_start(inode, 2);
3218         if (IS_ERR(handle))
3219                 goto out;
3220         if (current_handle &&
3221                 current_handle->h_transaction != handle->h_transaction) {
3222                 /* This task has a transaction open against a different fs */
3223                 printk(KERN_EMERG "%s: transactions do not match!\n",
3224                        __func__);
3225         } else {
3226                 jbd_debug(5, "marking dirty.  outer handle=%p\n",
3227                                 current_handle);
3228                 ext3_mark_inode_dirty(handle, inode);
3229         }
3230         ext3_journal_stop(handle);
3231 out:
3232         return;
3233 }
3234
3235 #if 0
3236 /*
3237  * Bind an inode's backing buffer_head into this transaction, to prevent
3238  * it from being flushed to disk early.  Unlike
3239  * ext3_reserve_inode_write, this leaves behind no bh reference and
3240  * returns no iloc structure, so the caller needs to repeat the iloc
3241  * lookup to mark the inode dirty later.
3242  */
3243 static int ext3_pin_inode(handle_t *handle, struct inode *inode)
3244 {
3245         struct ext3_iloc iloc;
3246
3247         int err = 0;
3248         if (handle) {
3249                 err = ext3_get_inode_loc(inode, &iloc);
3250                 if (!err) {
3251                         BUFFER_TRACE(iloc.bh, "get_write_access");
3252                         err = journal_get_write_access(handle, iloc.bh);
3253                         if (!err)
3254                                 err = ext3_journal_dirty_metadata(handle,
3255                                                                   iloc.bh);
3256                         brelse(iloc.bh);
3257                 }
3258         }
3259         ext3_std_error(inode->i_sb, err);
3260         return err;
3261 }
3262 #endif
3263
3264 int ext3_change_inode_journal_flag(struct inode *inode, int val)
3265 {
3266         journal_t *journal;
3267         handle_t *handle;
3268         int err;
3269
3270         /*
3271          * We have to be very careful here: changing a data block's
3272          * journaling status dynamically is dangerous.  If we write a
3273          * data block to the journal, change the status and then delete
3274          * that block, we risk forgetting to revoke the old log record
3275          * from the journal and so a subsequent replay can corrupt data.
3276          * So, first we make sure that the journal is empty and that
3277          * nobody is changing anything.
3278          */
3279
3280         journal = EXT3_JOURNAL(inode);
3281         if (is_journal_aborted(journal))
3282                 return -EROFS;
3283
3284         journal_lock_updates(journal);
3285         journal_flush(journal);
3286
3287         /*
3288          * OK, there are no updates running now, and all cached data is
3289          * synced to disk.  We are now in a completely consistent state
3290          * which doesn't have anything in the journal, and we know that
3291          * no filesystem updates are running, so it is safe to modify
3292          * the inode's in-core data-journaling state flag now.
3293          */
3294
3295         if (val)
3296                 EXT3_I(inode)->i_flags |= EXT3_JOURNAL_DATA_FL;
3297         else
3298                 EXT3_I(inode)->i_flags &= ~EXT3_JOURNAL_DATA_FL;
3299         ext3_set_aops(inode);
3300
3301         journal_unlock_updates(journal);
3302
3303         /* Finally we can mark the inode as dirty. */
3304
3305         handle = ext3_journal_start(inode, 1);
3306         if (IS_ERR(handle))
3307                 return PTR_ERR(handle);
3308
3309         err = ext3_mark_inode_dirty(handle, inode);
3310         handle->h_sync = 1;
3311         ext3_journal_stop(handle);
3312         ext3_std_error(inode->i_sb, err);
3313
3314         return err;
3315 }