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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/highuid.h>
26#include <linux/quotaops.h>
27#include <linux/writeback.h>
28#include <linux/mpage.h>
29#include <linux/namei.h>
30#include <linux/aio.h>
31#include "ext3.h"
32#include "xattr.h"
33#include "acl.h"
34
35static int ext3_writepage_trans_blocks(struct inode *inode);
36static int ext3_block_truncate_page(struct inode *inode, loff_t from);
37
38/*
39 * Test whether an inode is a fast symlink.
40 */
41static int ext3_inode_is_fast_symlink(struct inode *inode)
42{
43 int ea_blocks = EXT3_I(inode)->i_file_acl ?
44 (inode->i_sb->s_blocksize >> 9) : 0;
45
46 return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
47}
48
49/*
50 * The ext3 forget function must perform a revoke if we are freeing data
51 * which has been journaled. Metadata (eg. indirect blocks) must be
52 * revoked in all cases.
53 *
54 * "bh" may be NULL: a metadata block may have been freed from memory
55 * but there may still be a record of it in the journal, and that record
56 * still needs to be revoked.
57 */
58int ext3_forget(handle_t *handle, int is_metadata, struct inode *inode,
59 struct buffer_head *bh, ext3_fsblk_t blocknr)
60{
61 int err;
62
63 might_sleep();
64
65 trace_ext3_forget(inode, is_metadata, blocknr);
66 BUFFER_TRACE(bh, "enter");
67
68 jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
69 "data mode %lx\n",
70 bh, is_metadata, inode->i_mode,
71 test_opt(inode->i_sb, DATA_FLAGS));
72
73 /* Never use the revoke function if we are doing full data
74 * journaling: there is no need to, and a V1 superblock won't
75 * support it. Otherwise, only skip the revoke on un-journaled
76 * data blocks. */
77
78 if (test_opt(inode->i_sb, DATA_FLAGS) == EXT3_MOUNT_JOURNAL_DATA ||
79 (!is_metadata && !ext3_should_journal_data(inode))) {
80 if (bh) {
81 BUFFER_TRACE(bh, "call journal_forget");
82 return ext3_journal_forget(handle, bh);
83 }
84 return 0;
85 }
86
87 /*
88 * data!=journal && (is_metadata || should_journal_data(inode))
89 */
90 BUFFER_TRACE(bh, "call ext3_journal_revoke");
91 err = ext3_journal_revoke(handle, blocknr, bh);
92 if (err)
93 ext3_abort(inode->i_sb, __func__,
94 "error %d when attempting revoke", err);
95 BUFFER_TRACE(bh, "exit");
96 return err;
97}
98
99/*
100 * Work out how many blocks we need to proceed with the next chunk of a
101 * truncate transaction.
102 */
103static unsigned long blocks_for_truncate(struct inode *inode)
104{
105 unsigned long needed;
106
107 needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
108
109 /* Give ourselves just enough room to cope with inodes in which
110 * i_blocks is corrupt: we've seen disk corruptions in the past
111 * which resulted in random data in an inode which looked enough
112 * like a regular file for ext3 to try to delete it. Things
113 * will go a bit crazy if that happens, but at least we should
114 * try not to panic the whole kernel. */
115 if (needed < 2)
116 needed = 2;
117
118 /* But we need to bound the transaction so we don't overflow the
119 * journal. */
120 if (needed > EXT3_MAX_TRANS_DATA)
121 needed = EXT3_MAX_TRANS_DATA;
122
123 return EXT3_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
124}
125
126/*
127 * Truncate transactions can be complex and absolutely huge. So we need to
128 * be able to restart the transaction at a conventient checkpoint to make
129 * sure we don't overflow the journal.
130 *
131 * start_transaction gets us a new handle for a truncate transaction,
132 * and extend_transaction tries to extend the existing one a bit. If
133 * extend fails, we need to propagate the failure up and restart the
134 * transaction in the top-level truncate loop. --sct
135 */
136static handle_t *start_transaction(struct inode *inode)
137{
138 handle_t *result;
139
140 result = ext3_journal_start(inode, blocks_for_truncate(inode));
141 if (!IS_ERR(result))
142 return result;
143
144 ext3_std_error(inode->i_sb, PTR_ERR(result));
145 return result;
146}
147
148/*
149 * Try to extend this transaction for the purposes of truncation.
150 *
151 * Returns 0 if we managed to create more room. If we can't create more
152 * room, and the transaction must be restarted we return 1.
153 */
154static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
155{
156 if (handle->h_buffer_credits > EXT3_RESERVE_TRANS_BLOCKS)
157 return 0;
158 if (!ext3_journal_extend(handle, blocks_for_truncate(inode)))
159 return 0;
160 return 1;
161}
162
163/*
164 * Restart the transaction associated with *handle. This does a commit,
165 * so before we call here everything must be consistently dirtied against
166 * this transaction.
167 */
168static int truncate_restart_transaction(handle_t *handle, struct inode *inode)
169{
170 int ret;
171
172 jbd_debug(2, "restarting handle %p\n", handle);
173 /*
174 * Drop truncate_mutex to avoid deadlock with ext3_get_blocks_handle
175 * At this moment, get_block can be called only for blocks inside
176 * i_size since page cache has been already dropped and writes are
177 * blocked by i_mutex. So we can safely drop the truncate_mutex.
178 */
179 mutex_unlock(&EXT3_I(inode)->truncate_mutex);
180 ret = ext3_journal_restart(handle, blocks_for_truncate(inode));
181 mutex_lock(&EXT3_I(inode)->truncate_mutex);
182 return ret;
183}
184
185/*
186 * Called at inode eviction from icache
187 */
188void ext3_evict_inode (struct inode *inode)
189{
190 struct ext3_inode_info *ei = EXT3_I(inode);
191 struct ext3_block_alloc_info *rsv;
192 handle_t *handle;
193 int want_delete = 0;
194
195 trace_ext3_evict_inode(inode);
196 if (!inode->i_nlink && !is_bad_inode(inode)) {
197 dquot_initialize(inode);
198 want_delete = 1;
199 }
200
201 /*
202 * When journalling data dirty buffers are tracked only in the journal.
203 * So although mm thinks everything is clean and ready for reaping the
204 * inode might still have some pages to write in the running
205 * transaction or waiting to be checkpointed. Thus calling
206 * journal_invalidatepage() (via truncate_inode_pages()) to discard
207 * these buffers can cause data loss. Also even if we did not discard
208 * these buffers, we would have no way to find them after the inode
209 * is reaped and thus user could see stale data if he tries to read
210 * them before the transaction is checkpointed. So be careful and
211 * force everything to disk here... We use ei->i_datasync_tid to
212 * store the newest transaction containing inode's data.
213 *
214 * Note that directories do not have this problem because they don't
215 * use page cache.
216 *
217 * The s_journal check handles the case when ext3_get_journal() fails
218 * and puts the journal inode.
219 */
220 if (inode->i_nlink && ext3_should_journal_data(inode) &&
221 EXT3_SB(inode->i_sb)->s_journal &&
222 (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode)) &&
223 inode->i_ino != EXT3_JOURNAL_INO) {
224 tid_t commit_tid = atomic_read(&ei->i_datasync_tid);
225 journal_t *journal = EXT3_SB(inode->i_sb)->s_journal;
226
227 log_start_commit(journal, commit_tid);
228 log_wait_commit(journal, commit_tid);
229 filemap_write_and_wait(&inode->i_data);
230 }
231 truncate_inode_pages_final(&inode->i_data);
232
233 ext3_discard_reservation(inode);
234 rsv = ei->i_block_alloc_info;
235 ei->i_block_alloc_info = NULL;
236 if (unlikely(rsv))
237 kfree(rsv);
238
239 if (!want_delete)
240 goto no_delete;
241
242 handle = start_transaction(inode);
243 if (IS_ERR(handle)) {
244 /*
245 * If we're going to skip the normal cleanup, we still need to
246 * make sure that the in-core orphan linked list is properly
247 * cleaned up.
248 */
249 ext3_orphan_del(NULL, inode);
250 goto no_delete;
251 }
252
253 if (IS_SYNC(inode))
254 handle->h_sync = 1;
255 inode->i_size = 0;
256 if (inode->i_blocks)
257 ext3_truncate(inode);
258 /*
259 * Kill off the orphan record created when the inode lost the last
260 * link. Note that ext3_orphan_del() has to be able to cope with the
261 * deletion of a non-existent orphan - ext3_truncate() could
262 * have removed the record.
263 */
264 ext3_orphan_del(handle, inode);
265 ei->i_dtime = get_seconds();
266
267 /*
268 * One subtle ordering requirement: if anything has gone wrong
269 * (transaction abort, IO errors, whatever), then we can still
270 * do these next steps (the fs will already have been marked as
271 * having errors), but we can't free the inode if the mark_dirty
272 * fails.
273 */
274 if (ext3_mark_inode_dirty(handle, inode)) {
275 /* If that failed, just dquot_drop() and be done with that */
276 dquot_drop(inode);
277 clear_inode(inode);
278 } else {
279 ext3_xattr_delete_inode(handle, inode);
280 dquot_free_inode(inode);
281 dquot_drop(inode);
282 clear_inode(inode);
283 ext3_free_inode(handle, inode);
284 }
285 ext3_journal_stop(handle);
286 return;
287no_delete:
288 clear_inode(inode);
289 dquot_drop(inode);
290}
291
292typedef struct {
293 __le32 *p;
294 __le32 key;
295 struct buffer_head *bh;
296} Indirect;
297
298static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
299{
300 p->key = *(p->p = v);
301 p->bh = bh;
302}
303
304static int verify_chain(Indirect *from, Indirect *to)
305{
306 while (from <= to && from->key == *from->p)
307 from++;
308 return (from > to);
309}
310
311/**
312 * ext3_block_to_path - parse the block number into array of offsets
313 * @inode: inode in question (we are only interested in its superblock)
314 * @i_block: block number to be parsed
315 * @offsets: array to store the offsets in
316 * @boundary: set this non-zero if the referred-to block is likely to be
317 * followed (on disk) by an indirect block.
318 *
319 * To store the locations of file's data ext3 uses a data structure common
320 * for UNIX filesystems - tree of pointers anchored in the inode, with
321 * data blocks at leaves and indirect blocks in intermediate nodes.
322 * This function translates the block number into path in that tree -
323 * return value is the path length and @offsets[n] is the offset of
324 * pointer to (n+1)th node in the nth one. If @block is out of range
325 * (negative or too large) warning is printed and zero returned.
326 *
327 * Note: function doesn't find node addresses, so no IO is needed. All
328 * we need to know is the capacity of indirect blocks (taken from the
329 * inode->i_sb).
330 */
331
332/*
333 * Portability note: the last comparison (check that we fit into triple
334 * indirect block) is spelled differently, because otherwise on an
335 * architecture with 32-bit longs and 8Kb pages we might get into trouble
336 * if our filesystem had 8Kb blocks. We might use long long, but that would
337 * kill us on x86. Oh, well, at least the sign propagation does not matter -
338 * i_block would have to be negative in the very beginning, so we would not
339 * get there at all.
340 */
341
342static int ext3_block_to_path(struct inode *inode,
343 long i_block, int offsets[4], int *boundary)
344{
345 int ptrs = EXT3_ADDR_PER_BLOCK(inode->i_sb);
346 int ptrs_bits = EXT3_ADDR_PER_BLOCK_BITS(inode->i_sb);
347 const long direct_blocks = EXT3_NDIR_BLOCKS,
348 indirect_blocks = ptrs,
349 double_blocks = (1 << (ptrs_bits * 2));
350 int n = 0;
351 int final = 0;
352
353 if (i_block < 0) {
354 ext3_warning (inode->i_sb, "ext3_block_to_path", "block < 0");
355 } else if (i_block < direct_blocks) {
356 offsets[n++] = i_block;
357 final = direct_blocks;
358 } else if ( (i_block -= direct_blocks) < indirect_blocks) {
359 offsets[n++] = EXT3_IND_BLOCK;
360 offsets[n++] = i_block;
361 final = ptrs;
362 } else if ((i_block -= indirect_blocks) < double_blocks) {
363 offsets[n++] = EXT3_DIND_BLOCK;
364 offsets[n++] = i_block >> ptrs_bits;
365 offsets[n++] = i_block & (ptrs - 1);
366 final = ptrs;
367 } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
368 offsets[n++] = EXT3_TIND_BLOCK;
369 offsets[n++] = i_block >> (ptrs_bits * 2);
370 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
371 offsets[n++] = i_block & (ptrs - 1);
372 final = ptrs;
373 } else {
374 ext3_warning(inode->i_sb, "ext3_block_to_path", "block > big");
375 }
376 if (boundary)
377 *boundary = final - 1 - (i_block & (ptrs - 1));
378 return n;
379}
380
381/**
382 * ext3_get_branch - read the chain of indirect blocks leading to data
383 * @inode: inode in question
384 * @depth: depth of the chain (1 - direct pointer, etc.)
385 * @offsets: offsets of pointers in inode/indirect blocks
386 * @chain: place to store the result
387 * @err: here we store the error value
388 *
389 * Function fills the array of triples <key, p, bh> and returns %NULL
390 * if everything went OK or the pointer to the last filled triple
391 * (incomplete one) otherwise. Upon the return chain[i].key contains
392 * the number of (i+1)-th block in the chain (as it is stored in memory,
393 * i.e. little-endian 32-bit), chain[i].p contains the address of that
394 * number (it points into struct inode for i==0 and into the bh->b_data
395 * for i>0) and chain[i].bh points to the buffer_head of i-th indirect
396 * block for i>0 and NULL for i==0. In other words, it holds the block
397 * numbers of the chain, addresses they were taken from (and where we can
398 * verify that chain did not change) and buffer_heads hosting these
399 * numbers.
400 *
401 * Function stops when it stumbles upon zero pointer (absent block)
402 * (pointer to last triple returned, *@err == 0)
403 * or when it gets an IO error reading an indirect block
404 * (ditto, *@err == -EIO)
405 * or when it notices that chain had been changed while it was reading
406 * (ditto, *@err == -EAGAIN)
407 * or when it reads all @depth-1 indirect blocks successfully and finds
408 * the whole chain, all way to the data (returns %NULL, *err == 0).
409 */
410static Indirect *ext3_get_branch(struct inode *inode, int depth, int *offsets,
411 Indirect chain[4], int *err)
412{
413 struct super_block *sb = inode->i_sb;
414 Indirect *p = chain;
415 struct buffer_head *bh;
416
417 *err = 0;
418 /* i_data is not going away, no lock needed */
419 add_chain (chain, NULL, EXT3_I(inode)->i_data + *offsets);
420 if (!p->key)
421 goto no_block;
422 while (--depth) {
423 bh = sb_bread(sb, le32_to_cpu(p->key));
424 if (!bh)
425 goto failure;
426 /* Reader: pointers */
427 if (!verify_chain(chain, p))
428 goto changed;
429 add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
430 /* Reader: end */
431 if (!p->key)
432 goto no_block;
433 }
434 return NULL;
435
436changed:
437 brelse(bh);
438 *err = -EAGAIN;
439 goto no_block;
440failure:
441 *err = -EIO;
442no_block:
443 return p;
444}
445
446/**
447 * ext3_find_near - find a place for allocation with sufficient locality
448 * @inode: owner
449 * @ind: descriptor of indirect block.
450 *
451 * This function returns the preferred place for block allocation.
452 * It is used when heuristic for sequential allocation fails.
453 * Rules are:
454 * + if there is a block to the left of our position - allocate near it.
455 * + if pointer will live in indirect block - allocate near that block.
456 * + if pointer will live in inode - allocate in the same
457 * cylinder group.
458 *
459 * In the latter case we colour the starting block by the callers PID to
460 * prevent it from clashing with concurrent allocations for a different inode
461 * in the same block group. The PID is used here so that functionally related
462 * files will be close-by on-disk.
463 *
464 * Caller must make sure that @ind is valid and will stay that way.
465 */
466static ext3_fsblk_t ext3_find_near(struct inode *inode, Indirect *ind)
467{
468 struct ext3_inode_info *ei = EXT3_I(inode);
469 __le32 *start = ind->bh ? (__le32*) ind->bh->b_data : ei->i_data;
470 __le32 *p;
471 ext3_fsblk_t bg_start;
472 ext3_grpblk_t colour;
473
474 /* Try to find previous block */
475 for (p = ind->p - 1; p >= start; p--) {
476 if (*p)
477 return le32_to_cpu(*p);
478 }
479
480 /* No such thing, so let's try location of indirect block */
481 if (ind->bh)
482 return ind->bh->b_blocknr;
483
484 /*
485 * It is going to be referred to from the inode itself? OK, just put it
486 * into the same cylinder group then.
487 */
488 bg_start = ext3_group_first_block_no(inode->i_sb, ei->i_block_group);
489 colour = (current->pid % 16) *
490 (EXT3_BLOCKS_PER_GROUP(inode->i_sb) / 16);
491 return bg_start + colour;
492}
493
494/**
495 * ext3_find_goal - find a preferred place for allocation.
496 * @inode: owner
497 * @block: block we want
498 * @partial: pointer to the last triple within a chain
499 *
500 * Normally this function find the preferred place for block allocation,
501 * returns it.
502 */
503
504static ext3_fsblk_t ext3_find_goal(struct inode *inode, long block,
505 Indirect *partial)
506{
507 struct ext3_block_alloc_info *block_i;
508
509 block_i = EXT3_I(inode)->i_block_alloc_info;
510
511 /*
512 * try the heuristic for sequential allocation,
513 * failing that at least try to get decent locality.
514 */
515 if (block_i && (block == block_i->last_alloc_logical_block + 1)
516 && (block_i->last_alloc_physical_block != 0)) {
517 return block_i->last_alloc_physical_block + 1;
518 }
519
520 return ext3_find_near(inode, partial);
521}
522
523/**
524 * ext3_blks_to_allocate - Look up the block map and count the number
525 * of direct blocks need to be allocated for the given branch.
526 *
527 * @branch: chain of indirect blocks
528 * @k: number of blocks need for indirect blocks
529 * @blks: number of data blocks to be mapped.
530 * @blocks_to_boundary: the offset in the indirect block
531 *
532 * return the total number of blocks to be allocate, including the
533 * direct and indirect blocks.
534 */
535static int ext3_blks_to_allocate(Indirect *branch, int k, unsigned long blks,
536 int blocks_to_boundary)
537{
538 unsigned long count = 0;
539
540 /*
541 * Simple case, [t,d]Indirect block(s) has not allocated yet
542 * then it's clear blocks on that path have not allocated
543 */
544 if (k > 0) {
545 /* right now we don't handle cross boundary allocation */
546 if (blks < blocks_to_boundary + 1)
547 count += blks;
548 else
549 count += blocks_to_boundary + 1;
550 return count;
551 }
552
553 count++;
554 while (count < blks && count <= blocks_to_boundary &&
555 le32_to_cpu(*(branch[0].p + count)) == 0) {
556 count++;
557 }
558 return count;
559}
560
561/**
562 * ext3_alloc_blocks - multiple allocate blocks needed for a branch
563 * @handle: handle for this transaction
564 * @inode: owner
565 * @goal: preferred place for allocation
566 * @indirect_blks: the number of blocks need to allocate for indirect
567 * blocks
568 * @blks: number of blocks need to allocated for direct blocks
569 * @new_blocks: on return it will store the new block numbers for
570 * the indirect blocks(if needed) and the first direct block,
571 * @err: here we store the error value
572 *
573 * return the number of direct blocks allocated
574 */
575static int ext3_alloc_blocks(handle_t *handle, struct inode *inode,
576 ext3_fsblk_t goal, int indirect_blks, int blks,
577 ext3_fsblk_t new_blocks[4], int *err)
578{
579 int target, i;
580 unsigned long count = 0;
581 int index = 0;
582 ext3_fsblk_t current_block = 0;
583 int ret = 0;
584
585 /*
586 * Here we try to allocate the requested multiple blocks at once,
587 * on a best-effort basis.
588 * To build a branch, we should allocate blocks for
589 * the indirect blocks(if not allocated yet), and at least
590 * the first direct block of this branch. That's the
591 * minimum number of blocks need to allocate(required)
592 */
593 target = blks + indirect_blks;
594
595 while (1) {
596 count = target;
597 /* allocating blocks for indirect blocks and direct blocks */
598 current_block = ext3_new_blocks(handle,inode,goal,&count,err);
599 if (*err)
600 goto failed_out;
601
602 target -= count;
603 /* allocate blocks for indirect blocks */
604 while (index < indirect_blks && count) {
605 new_blocks[index++] = current_block++;
606 count--;
607 }
608
609 if (count > 0)
610 break;
611 }
612
613 /* save the new block number for the first direct block */
614 new_blocks[index] = current_block;
615
616 /* total number of blocks allocated for direct blocks */
617 ret = count;
618 *err = 0;
619 return ret;
620failed_out:
621 for (i = 0; i <index; i++)
622 ext3_free_blocks(handle, inode, new_blocks[i], 1);
623 return ret;
624}
625
626/**
627 * ext3_alloc_branch - allocate and set up a chain of blocks.
628 * @handle: handle for this transaction
629 * @inode: owner
630 * @indirect_blks: number of allocated indirect blocks
631 * @blks: number of allocated direct blocks
632 * @goal: preferred place for allocation
633 * @offsets: offsets (in the blocks) to store the pointers to next.
634 * @branch: place to store the chain in.
635 *
636 * This function allocates blocks, zeroes out all but the last one,
637 * links them into chain and (if we are synchronous) writes them to disk.
638 * In other words, it prepares a branch that can be spliced onto the
639 * inode. It stores the information about that chain in the branch[], in
640 * the same format as ext3_get_branch() would do. We are calling it after
641 * we had read the existing part of chain and partial points to the last
642 * triple of that (one with zero ->key). Upon the exit we have the same
643 * picture as after the successful ext3_get_block(), except that in one
644 * place chain is disconnected - *branch->p is still zero (we did not
645 * set the last link), but branch->key contains the number that should
646 * be placed into *branch->p to fill that gap.
647 *
648 * If allocation fails we free all blocks we've allocated (and forget
649 * their buffer_heads) and return the error value the from failed
650 * ext3_alloc_block() (normally -ENOSPC). Otherwise we set the chain
651 * as described above and return 0.
652 */
653static int ext3_alloc_branch(handle_t *handle, struct inode *inode,
654 int indirect_blks, int *blks, ext3_fsblk_t goal,
655 int *offsets, Indirect *branch)
656{
657 int blocksize = inode->i_sb->s_blocksize;
658 int i, n = 0;
659 int err = 0;
660 struct buffer_head *bh;
661 int num;
662 ext3_fsblk_t new_blocks[4];
663 ext3_fsblk_t current_block;
664
665 num = ext3_alloc_blocks(handle, inode, goal, indirect_blks,
666 *blks, new_blocks, &err);
667 if (err)
668 return err;
669
670 branch[0].key = cpu_to_le32(new_blocks[0]);
671 /*
672 * metadata blocks and data blocks are allocated.
673 */
674 for (n = 1; n <= indirect_blks; n++) {
675 /*
676 * Get buffer_head for parent block, zero it out
677 * and set the pointer to new one, then send
678 * parent to disk.
679 */
680 bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
681 if (unlikely(!bh)) {
682 err = -ENOMEM;
683 goto failed;
684 }
685 branch[n].bh = bh;
686 lock_buffer(bh);
687 BUFFER_TRACE(bh, "call get_create_access");
688 err = ext3_journal_get_create_access(handle, bh);
689 if (err) {
690 unlock_buffer(bh);
691 brelse(bh);
692 goto failed;
693 }
694
695 memset(bh->b_data, 0, blocksize);
696 branch[n].p = (__le32 *) bh->b_data + offsets[n];
697 branch[n].key = cpu_to_le32(new_blocks[n]);
698 *branch[n].p = branch[n].key;
699 if ( n == indirect_blks) {
700 current_block = new_blocks[n];
701 /*
702 * End of chain, update the last new metablock of
703 * the chain to point to the new allocated
704 * data blocks numbers
705 */
706 for (i=1; i < num; i++)
707 *(branch[n].p + i) = cpu_to_le32(++current_block);
708 }
709 BUFFER_TRACE(bh, "marking uptodate");
710 set_buffer_uptodate(bh);
711 unlock_buffer(bh);
712
713 BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
714 err = ext3_journal_dirty_metadata(handle, bh);
715 if (err)
716 goto failed;
717 }
718 *blks = num;
719 return err;
720failed:
721 /* Allocation failed, free what we already allocated */
722 for (i = 1; i <= n ; i++) {
723 BUFFER_TRACE(branch[i].bh, "call journal_forget");
724 ext3_journal_forget(handle, branch[i].bh);
725 }
726 for (i = 0; i < indirect_blks; i++)
727 ext3_free_blocks(handle, inode, new_blocks[i], 1);
728
729 ext3_free_blocks(handle, inode, new_blocks[i], num);
730
731 return err;
732}
733
734/**
735 * ext3_splice_branch - splice the allocated branch onto inode.
736 * @handle: handle for this transaction
737 * @inode: owner
738 * @block: (logical) number of block we are adding
739 * @where: location of missing link
740 * @num: number of indirect blocks we are adding
741 * @blks: number of direct blocks we are adding
742 *
743 * This function fills the missing link and does all housekeeping needed in
744 * inode (->i_blocks, etc.). In case of success we end up with the full
745 * chain to new block and return 0.
746 */
747static int ext3_splice_branch(handle_t *handle, struct inode *inode,
748 long block, Indirect *where, int num, int blks)
749{
750 int i;
751 int err = 0;
752 struct ext3_block_alloc_info *block_i;
753 ext3_fsblk_t current_block;
754 struct ext3_inode_info *ei = EXT3_I(inode);
755 struct timespec now;
756
757 block_i = ei->i_block_alloc_info;
758 /*
759 * If we're splicing into a [td]indirect block (as opposed to the
760 * inode) then we need to get write access to the [td]indirect block
761 * before the splice.
762 */
763 if (where->bh) {
764 BUFFER_TRACE(where->bh, "get_write_access");
765 err = ext3_journal_get_write_access(handle, where->bh);
766 if (err)
767 goto err_out;
768 }
769 /* That's it */
770
771 *where->p = where->key;
772
773 /*
774 * Update the host buffer_head or inode to point to more just allocated
775 * direct blocks blocks
776 */
777 if (num == 0 && blks > 1) {
778 current_block = le32_to_cpu(where->key) + 1;
779 for (i = 1; i < blks; i++)
780 *(where->p + i ) = cpu_to_le32(current_block++);
781 }
782
783 /*
784 * update the most recently allocated logical & physical block
785 * in i_block_alloc_info, to assist find the proper goal block for next
786 * allocation
787 */
788 if (block_i) {
789 block_i->last_alloc_logical_block = block + blks - 1;
790 block_i->last_alloc_physical_block =
791 le32_to_cpu(where[num].key) + blks - 1;
792 }
793
794 /* We are done with atomic stuff, now do the rest of housekeeping */
795 now = CURRENT_TIME_SEC;
796 if (!timespec_equal(&inode->i_ctime, &now) || !where->bh) {
797 inode->i_ctime = now;
798 ext3_mark_inode_dirty(handle, inode);
799 }
800 /* ext3_mark_inode_dirty already updated i_sync_tid */
801 atomic_set(&ei->i_datasync_tid, handle->h_transaction->t_tid);
802
803 /* had we spliced it onto indirect block? */
804 if (where->bh) {
805 /*
806 * If we spliced it onto an indirect block, we haven't
807 * altered the inode. Note however that if it is being spliced
808 * onto an indirect block at the very end of the file (the
809 * file is growing) then we *will* alter the inode to reflect
810 * the new i_size. But that is not done here - it is done in
811 * generic_commit_write->__mark_inode_dirty->ext3_dirty_inode.
812 */
813 jbd_debug(5, "splicing indirect only\n");
814 BUFFER_TRACE(where->bh, "call ext3_journal_dirty_metadata");
815 err = ext3_journal_dirty_metadata(handle, where->bh);
816 if (err)
817 goto err_out;
818 } else {
819 /*
820 * OK, we spliced it into the inode itself on a direct block.
821 * Inode was dirtied above.
822 */
823 jbd_debug(5, "splicing direct\n");
824 }
825 return err;
826
827err_out:
828 for (i = 1; i <= num; i++) {
829 BUFFER_TRACE(where[i].bh, "call journal_forget");
830 ext3_journal_forget(handle, where[i].bh);
831 ext3_free_blocks(handle,inode,le32_to_cpu(where[i-1].key),1);
832 }
833 ext3_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks);
834
835 return err;
836}
837
838/*
839 * Allocation strategy is simple: if we have to allocate something, we will
840 * have to go the whole way to leaf. So let's do it before attaching anything
841 * to tree, set linkage between the newborn blocks, write them if sync is
842 * required, recheck the path, free and repeat if check fails, otherwise
843 * set the last missing link (that will protect us from any truncate-generated
844 * removals - all blocks on the path are immune now) and possibly force the
845 * write on the parent block.
846 * That has a nice additional property: no special recovery from the failed
847 * allocations is needed - we simply release blocks and do not touch anything
848 * reachable from inode.
849 *
850 * `handle' can be NULL if create == 0.
851 *
852 * The BKL may not be held on entry here. Be sure to take it early.
853 * return > 0, # of blocks mapped or allocated.
854 * return = 0, if plain lookup failed.
855 * return < 0, error case.
856 */
857int ext3_get_blocks_handle(handle_t *handle, struct inode *inode,
858 sector_t iblock, unsigned long maxblocks,
859 struct buffer_head *bh_result,
860 int create)
861{
862 int err = -EIO;
863 int offsets[4];
864 Indirect chain[4];
865 Indirect *partial;
866 ext3_fsblk_t goal;
867 int indirect_blks;
868 int blocks_to_boundary = 0;
869 int depth;
870 struct ext3_inode_info *ei = EXT3_I(inode);
871 int count = 0;
872 ext3_fsblk_t first_block = 0;
873
874
875 trace_ext3_get_blocks_enter(inode, iblock, maxblocks, create);
876 J_ASSERT(handle != NULL || create == 0);
877 depth = ext3_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
878
879 if (depth == 0)
880 goto out;
881
882 partial = ext3_get_branch(inode, depth, offsets, chain, &err);
883
884 /* Simplest case - block found, no allocation needed */
885 if (!partial) {
886 first_block = le32_to_cpu(chain[depth - 1].key);
887 clear_buffer_new(bh_result);
888 count++;
889 /*map more blocks*/
890 while (count < maxblocks && count <= blocks_to_boundary) {
891 ext3_fsblk_t blk;
892
893 if (!verify_chain(chain, chain + depth - 1)) {
894 /*
895 * Indirect block might be removed by
896 * truncate while we were reading it.
897 * Handling of that case: forget what we've
898 * got now. Flag the err as EAGAIN, so it
899 * will reread.
900 */
901 err = -EAGAIN;
902 count = 0;
903 break;
904 }
905 blk = le32_to_cpu(*(chain[depth-1].p + count));
906
907 if (blk == first_block + count)
908 count++;
909 else
910 break;
911 }
912 if (err != -EAGAIN)
913 goto got_it;
914 }
915
916 /* Next simple case - plain lookup or failed read of indirect block */
917 if (!create || err == -EIO)
918 goto cleanup;
919
920 /*
921 * Block out ext3_truncate while we alter the tree
922 */
923 mutex_lock(&ei->truncate_mutex);
924
925 /*
926 * If the indirect block is missing while we are reading
927 * the chain(ext3_get_branch() returns -EAGAIN err), or
928 * if the chain has been changed after we grab the semaphore,
929 * (either because another process truncated this branch, or
930 * another get_block allocated this branch) re-grab the chain to see if
931 * the request block has been allocated or not.
932 *
933 * Since we already block the truncate/other get_block
934 * at this point, we will have the current copy of the chain when we
935 * splice the branch into the tree.
936 */
937 if (err == -EAGAIN || !verify_chain(chain, partial)) {
938 while (partial > chain) {
939 brelse(partial->bh);
940 partial--;
941 }
942 partial = ext3_get_branch(inode, depth, offsets, chain, &err);
943 if (!partial) {
944 count++;
945 mutex_unlock(&ei->truncate_mutex);
946 if (err)
947 goto cleanup;
948 clear_buffer_new(bh_result);
949 goto got_it;
950 }
951 }
952
953 /*
954 * Okay, we need to do block allocation. Lazily initialize the block
955 * allocation info here if necessary
956 */
957 if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
958 ext3_init_block_alloc_info(inode);
959
960 goal = ext3_find_goal(inode, iblock, partial);
961
962 /* the number of blocks need to allocate for [d,t]indirect blocks */
963 indirect_blks = (chain + depth) - partial - 1;
964
965 /*
966 * Next look up the indirect map to count the totoal number of
967 * direct blocks to allocate for this branch.
968 */
969 count = ext3_blks_to_allocate(partial, indirect_blks,
970 maxblocks, blocks_to_boundary);
971 err = ext3_alloc_branch(handle, inode, indirect_blks, &count, goal,
972 offsets + (partial - chain), partial);
973
974 /*
975 * The ext3_splice_branch call will free and forget any buffers
976 * on the new chain if there is a failure, but that risks using
977 * up transaction credits, especially for bitmaps where the
978 * credits cannot be returned. Can we handle this somehow? We
979 * may need to return -EAGAIN upwards in the worst case. --sct
980 */
981 if (!err)
982 err = ext3_splice_branch(handle, inode, iblock,
983 partial, indirect_blks, count);
984 mutex_unlock(&ei->truncate_mutex);
985 if (err)
986 goto cleanup;
987
988 set_buffer_new(bh_result);
989got_it:
990 map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
991 if (count > blocks_to_boundary)
992 set_buffer_boundary(bh_result);
993 err = count;
994 /* Clean up and exit */
995 partial = chain + depth - 1; /* the whole chain */
996cleanup:
997 while (partial > chain) {
998 BUFFER_TRACE(partial->bh, "call brelse");
999 brelse(partial->bh);
1000 partial--;
1001 }
1002 BUFFER_TRACE(bh_result, "returned");
1003out:
1004 trace_ext3_get_blocks_exit(inode, iblock,
1005 depth ? le32_to_cpu(chain[depth-1].key) : 0,
1006 count, err);
1007 return err;
1008}
1009
1010/* Maximum number of blocks we map for direct IO at once. */
1011#define DIO_MAX_BLOCKS 4096
1012/*
1013 * Number of credits we need for writing DIO_MAX_BLOCKS:
1014 * We need sb + group descriptor + bitmap + inode -> 4
1015 * For B blocks with A block pointers per block we need:
1016 * 1 (triple ind.) + (B/A/A + 2) (doubly ind.) + (B/A + 2) (indirect).
1017 * If we plug in 4096 for B and 256 for A (for 1KB block size), we get 25.
1018 */
1019#define DIO_CREDITS 25
1020
1021static int ext3_get_block(struct inode *inode, sector_t iblock,
1022 struct buffer_head *bh_result, int create)
1023{
1024 handle_t *handle = ext3_journal_current_handle();
1025 int ret = 0, started = 0;
1026 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
1027
1028 if (create && !handle) { /* Direct IO write... */
1029 if (max_blocks > DIO_MAX_BLOCKS)
1030 max_blocks = DIO_MAX_BLOCKS;
1031 handle = ext3_journal_start(inode, DIO_CREDITS +
1032 EXT3_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb));
1033 if (IS_ERR(handle)) {
1034 ret = PTR_ERR(handle);
1035 goto out;
1036 }
1037 started = 1;
1038 }
1039
1040 ret = ext3_get_blocks_handle(handle, inode, iblock,
1041 max_blocks, bh_result, create);
1042 if (ret > 0) {
1043 bh_result->b_size = (ret << inode->i_blkbits);
1044 ret = 0;
1045 }
1046 if (started)
1047 ext3_journal_stop(handle);
1048out:
1049 return ret;
1050}
1051
1052int ext3_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
1053 u64 start, u64 len)
1054{
1055 return generic_block_fiemap(inode, fieinfo, start, len,
1056 ext3_get_block);
1057}
1058
1059/*
1060 * `handle' can be NULL if create is zero
1061 */
1062struct buffer_head *ext3_getblk(handle_t *handle, struct inode *inode,
1063 long block, int create, int *errp)
1064{
1065 struct buffer_head dummy;
1066 int fatal = 0, err;
1067
1068 J_ASSERT(handle != NULL || create == 0);
1069
1070 dummy.b_state = 0;
1071 dummy.b_blocknr = -1000;
1072 buffer_trace_init(&dummy.b_history);
1073 err = ext3_get_blocks_handle(handle, inode, block, 1,
1074 &dummy, create);
1075 /*
1076 * ext3_get_blocks_handle() returns number of blocks
1077 * mapped. 0 in case of a HOLE.
1078 */
1079 if (err > 0) {
1080 WARN_ON(err > 1);
1081 err = 0;
1082 }
1083 *errp = err;
1084 if (!err && buffer_mapped(&dummy)) {
1085 struct buffer_head *bh;
1086 bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
1087 if (unlikely(!bh)) {
1088 *errp = -ENOMEM;
1089 goto err;
1090 }
1091 if (buffer_new(&dummy)) {
1092 J_ASSERT(create != 0);
1093 J_ASSERT(handle != NULL);
1094
1095 /*
1096 * Now that we do not always journal data, we should
1097 * keep in mind whether this should always journal the
1098 * new buffer as metadata. For now, regular file
1099 * writes use ext3_get_block instead, so it's not a
1100 * problem.
1101 */
1102 lock_buffer(bh);
1103 BUFFER_TRACE(bh, "call get_create_access");
1104 fatal = ext3_journal_get_create_access(handle, bh);
1105 if (!fatal && !buffer_uptodate(bh)) {
1106 memset(bh->b_data,0,inode->i_sb->s_blocksize);
1107 set_buffer_uptodate(bh);
1108 }
1109 unlock_buffer(bh);
1110 BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
1111 err = ext3_journal_dirty_metadata(handle, bh);
1112 if (!fatal)
1113 fatal = err;
1114 } else {
1115 BUFFER_TRACE(bh, "not a new buffer");
1116 }
1117 if (fatal) {
1118 *errp = fatal;
1119 brelse(bh);
1120 bh = NULL;
1121 }
1122 return bh;
1123 }
1124err:
1125 return NULL;
1126}
1127
1128struct buffer_head *ext3_bread(handle_t *handle, struct inode *inode,
1129 int block, int create, int *err)
1130{
1131 struct buffer_head * bh;
1132
1133 bh = ext3_getblk(handle, inode, block, create, err);
1134 if (!bh)
1135 return bh;
1136 if (bh_uptodate_or_lock(bh))
1137 return bh;
1138 get_bh(bh);
1139 bh->b_end_io = end_buffer_read_sync;
1140 submit_bh(READ | REQ_META | REQ_PRIO, bh);
1141 wait_on_buffer(bh);
1142 if (buffer_uptodate(bh))
1143 return bh;
1144 put_bh(bh);
1145 *err = -EIO;
1146 return NULL;
1147}
1148
1149static int walk_page_buffers( handle_t *handle,
1150 struct buffer_head *head,
1151 unsigned from,
1152 unsigned to,
1153 int *partial,
1154 int (*fn)( handle_t *handle,
1155 struct buffer_head *bh))
1156{
1157 struct buffer_head *bh;
1158 unsigned block_start, block_end;
1159 unsigned blocksize = head->b_size;
1160 int err, ret = 0;
1161 struct buffer_head *next;
1162
1163 for ( bh = head, block_start = 0;
1164 ret == 0 && (bh != head || !block_start);
1165 block_start = block_end, bh = next)
1166 {
1167 next = bh->b_this_page;
1168 block_end = block_start + blocksize;
1169 if (block_end <= from || block_start >= to) {
1170 if (partial && !buffer_uptodate(bh))
1171 *partial = 1;
1172 continue;
1173 }
1174 err = (*fn)(handle, bh);
1175 if (!ret)
1176 ret = err;
1177 }
1178 return ret;
1179}
1180
1181/*
1182 * To preserve ordering, it is essential that the hole instantiation and
1183 * the data write be encapsulated in a single transaction. We cannot
1184 * close off a transaction and start a new one between the ext3_get_block()
1185 * and the commit_write(). So doing the journal_start at the start of
1186 * prepare_write() is the right place.
1187 *
1188 * Also, this function can nest inside ext3_writepage() ->
1189 * block_write_full_page(). In that case, we *know* that ext3_writepage()
1190 * has generated enough buffer credits to do the whole page. So we won't
1191 * block on the journal in that case, which is good, because the caller may
1192 * be PF_MEMALLOC.
1193 *
1194 * By accident, ext3 can be reentered when a transaction is open via
1195 * quota file writes. If we were to commit the transaction while thus
1196 * reentered, there can be a deadlock - we would be holding a quota
1197 * lock, and the commit would never complete if another thread had a
1198 * transaction open and was blocking on the quota lock - a ranking
1199 * violation.
1200 *
1201 * So what we do is to rely on the fact that journal_stop/journal_start
1202 * will _not_ run commit under these circumstances because handle->h_ref
1203 * is elevated. We'll still have enough credits for the tiny quotafile
1204 * write.
1205 */
1206static int do_journal_get_write_access(handle_t *handle,
1207 struct buffer_head *bh)
1208{
1209 int dirty = buffer_dirty(bh);
1210 int ret;
1211
1212 if (!buffer_mapped(bh) || buffer_freed(bh))
1213 return 0;
1214 /*
1215 * __block_prepare_write() could have dirtied some buffers. Clean
1216 * the dirty bit as jbd2_journal_get_write_access() could complain
1217 * otherwise about fs integrity issues. Setting of the dirty bit
1218 * by __block_prepare_write() isn't a real problem here as we clear
1219 * the bit before releasing a page lock and thus writeback cannot
1220 * ever write the buffer.
1221 */
1222 if (dirty)
1223 clear_buffer_dirty(bh);
1224 ret = ext3_journal_get_write_access(handle, bh);
1225 if (!ret && dirty)
1226 ret = ext3_journal_dirty_metadata(handle, bh);
1227 return ret;
1228}
1229
1230/*
1231 * Truncate blocks that were not used by write. We have to truncate the
1232 * pagecache as well so that corresponding buffers get properly unmapped.
1233 */
1234static void ext3_truncate_failed_write(struct inode *inode)
1235{
1236 truncate_inode_pages(inode->i_mapping, inode->i_size);
1237 ext3_truncate(inode);
1238}
1239
1240/*
1241 * Truncate blocks that were not used by direct IO write. We have to zero out
1242 * the last file block as well because direct IO might have written to it.
1243 */
1244static void ext3_truncate_failed_direct_write(struct inode *inode)
1245{
1246 ext3_block_truncate_page(inode, inode->i_size);
1247 ext3_truncate(inode);
1248}
1249
1250static int ext3_write_begin(struct file *file, struct address_space *mapping,
1251 loff_t pos, unsigned len, unsigned flags,
1252 struct page **pagep, void **fsdata)
1253{
1254 struct inode *inode = mapping->host;
1255 int ret;
1256 handle_t *handle;
1257 int retries = 0;
1258 struct page *page;
1259 pgoff_t index;
1260 unsigned from, to;
1261 /* Reserve one block more for addition to orphan list in case
1262 * we allocate blocks but write fails for some reason */
1263 int needed_blocks = ext3_writepage_trans_blocks(inode) + 1;
1264
1265 trace_ext3_write_begin(inode, pos, len, flags);
1266
1267 index = pos >> PAGE_CACHE_SHIFT;
1268 from = pos & (PAGE_CACHE_SIZE - 1);
1269 to = from + len;
1270
1271retry:
1272 page = grab_cache_page_write_begin(mapping, index, flags);
1273 if (!page)
1274 return -ENOMEM;
1275 *pagep = page;
1276
1277 handle = ext3_journal_start(inode, needed_blocks);
1278 if (IS_ERR(handle)) {
1279 unlock_page(page);
1280 page_cache_release(page);
1281 ret = PTR_ERR(handle);
1282 goto out;
1283 }
1284 ret = __block_write_begin(page, pos, len, ext3_get_block);
1285 if (ret)
1286 goto write_begin_failed;
1287
1288 if (ext3_should_journal_data(inode)) {
1289 ret = walk_page_buffers(handle, page_buffers(page),
1290 from, to, NULL, do_journal_get_write_access);
1291 }
1292write_begin_failed:
1293 if (ret) {
1294 /*
1295 * block_write_begin may have instantiated a few blocks
1296 * outside i_size. Trim these off again. Don't need
1297 * i_size_read because we hold i_mutex.
1298 *
1299 * Add inode to orphan list in case we crash before truncate
1300 * finishes. Do this only if ext3_can_truncate() agrees so
1301 * that orphan processing code is happy.
1302 */
1303 if (pos + len > inode->i_size && ext3_can_truncate(inode))
1304 ext3_orphan_add(handle, inode);
1305 ext3_journal_stop(handle);
1306 unlock_page(page);
1307 page_cache_release(page);
1308 if (pos + len > inode->i_size)
1309 ext3_truncate_failed_write(inode);
1310 }
1311 if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
1312 goto retry;
1313out:
1314 return ret;
1315}
1316
1317
1318int ext3_journal_dirty_data(handle_t *handle, struct buffer_head *bh)
1319{
1320 int err = journal_dirty_data(handle, bh);
1321 if (err)
1322 ext3_journal_abort_handle(__func__, __func__,
1323 bh, handle, err);
1324 return err;
1325}
1326
1327/* For ordered writepage and write_end functions */
1328static int journal_dirty_data_fn(handle_t *handle, struct buffer_head *bh)
1329{
1330 /*
1331 * Write could have mapped the buffer but it didn't copy the data in
1332 * yet. So avoid filing such buffer into a transaction.
1333 */
1334 if (buffer_mapped(bh) && buffer_uptodate(bh))
1335 return ext3_journal_dirty_data(handle, bh);
1336 return 0;
1337}
1338
1339/* For write_end() in data=journal mode */
1340static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1341{
1342 if (!buffer_mapped(bh) || buffer_freed(bh))
1343 return 0;
1344 set_buffer_uptodate(bh);
1345 return ext3_journal_dirty_metadata(handle, bh);
1346}
1347
1348/*
1349 * This is nasty and subtle: ext3_write_begin() could have allocated blocks
1350 * for the whole page but later we failed to copy the data in. Update inode
1351 * size according to what we managed to copy. The rest is going to be
1352 * truncated in write_end function.
1353 */
1354static void update_file_sizes(struct inode *inode, loff_t pos, unsigned copied)
1355{
1356 /* What matters to us is i_disksize. We don't write i_size anywhere */
1357 if (pos + copied > inode->i_size)
1358 i_size_write(inode, pos + copied);
1359 if (pos + copied > EXT3_I(inode)->i_disksize) {
1360 EXT3_I(inode)->i_disksize = pos + copied;
1361 mark_inode_dirty(inode);
1362 }
1363}
1364
1365/*
1366 * We need to pick up the new inode size which generic_commit_write gave us
1367 * `file' can be NULL - eg, when called from page_symlink().
1368 *
1369 * ext3 never places buffers on inode->i_mapping->private_list. metadata
1370 * buffers are managed internally.
1371 */
1372static int ext3_ordered_write_end(struct file *file,
1373 struct address_space *mapping,
1374 loff_t pos, unsigned len, unsigned copied,
1375 struct page *page, void *fsdata)
1376{
1377 handle_t *handle = ext3_journal_current_handle();
1378 struct inode *inode = file->f_mapping->host;
1379 unsigned from, to;
1380 int ret = 0, ret2;
1381
1382 trace_ext3_ordered_write_end(inode, pos, len, copied);
1383 copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
1384
1385 from = pos & (PAGE_CACHE_SIZE - 1);
1386 to = from + copied;
1387 ret = walk_page_buffers(handle, page_buffers(page),
1388 from, to, NULL, journal_dirty_data_fn);
1389
1390 if (ret == 0)
1391 update_file_sizes(inode, pos, copied);
1392 /*
1393 * There may be allocated blocks outside of i_size because
1394 * we failed to copy some data. Prepare for truncate.
1395 */
1396 if (pos + len > inode->i_size && ext3_can_truncate(inode))
1397 ext3_orphan_add(handle, inode);
1398 ret2 = ext3_journal_stop(handle);
1399 if (!ret)
1400 ret = ret2;
1401 unlock_page(page);
1402 page_cache_release(page);
1403
1404 if (pos + len > inode->i_size)
1405 ext3_truncate_failed_write(inode);
1406 return ret ? ret : copied;
1407}
1408
1409static int ext3_writeback_write_end(struct file *file,
1410 struct address_space *mapping,
1411 loff_t pos, unsigned len, unsigned copied,
1412 struct page *page, void *fsdata)
1413{
1414 handle_t *handle = ext3_journal_current_handle();
1415 struct inode *inode = file->f_mapping->host;
1416 int ret;
1417
1418 trace_ext3_writeback_write_end(inode, pos, len, copied);
1419 copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
1420 update_file_sizes(inode, pos, copied);
1421 /*
1422 * There may be allocated blocks outside of i_size because
1423 * we failed to copy some data. Prepare for truncate.
1424 */
1425 if (pos + len > inode->i_size && ext3_can_truncate(inode))
1426 ext3_orphan_add(handle, inode);
1427 ret = ext3_journal_stop(handle);
1428 unlock_page(page);
1429 page_cache_release(page);
1430
1431 if (pos + len > inode->i_size)
1432 ext3_truncate_failed_write(inode);
1433 return ret ? ret : copied;
1434}
1435
1436static int ext3_journalled_write_end(struct file *file,
1437 struct address_space *mapping,
1438 loff_t pos, unsigned len, unsigned copied,
1439 struct page *page, void *fsdata)
1440{
1441 handle_t *handle = ext3_journal_current_handle();
1442 struct inode *inode = mapping->host;
1443 struct ext3_inode_info *ei = EXT3_I(inode);
1444 int ret = 0, ret2;
1445 int partial = 0;
1446 unsigned from, to;
1447
1448 trace_ext3_journalled_write_end(inode, pos, len, copied);
1449 from = pos & (PAGE_CACHE_SIZE - 1);
1450 to = from + len;
1451
1452 if (copied < len) {
1453 if (!PageUptodate(page))
1454 copied = 0;
1455 page_zero_new_buffers(page, from + copied, to);
1456 to = from + copied;
1457 }
1458
1459 ret = walk_page_buffers(handle, page_buffers(page), from,
1460 to, &partial, write_end_fn);
1461 if (!partial)
1462 SetPageUptodate(page);
1463
1464 if (pos + copied > inode->i_size)
1465 i_size_write(inode, pos + copied);
1466 /*
1467 * There may be allocated blocks outside of i_size because
1468 * we failed to copy some data. Prepare for truncate.
1469 */
1470 if (pos + len > inode->i_size && ext3_can_truncate(inode))
1471 ext3_orphan_add(handle, inode);
1472 ext3_set_inode_state(inode, EXT3_STATE_JDATA);
1473 atomic_set(&ei->i_datasync_tid, handle->h_transaction->t_tid);
1474 if (inode->i_size > ei->i_disksize) {
1475 ei->i_disksize = inode->i_size;
1476 ret2 = ext3_mark_inode_dirty(handle, inode);
1477 if (!ret)
1478 ret = ret2;
1479 }
1480
1481 ret2 = ext3_journal_stop(handle);
1482 if (!ret)
1483 ret = ret2;
1484 unlock_page(page);
1485 page_cache_release(page);
1486
1487 if (pos + len > inode->i_size)
1488 ext3_truncate_failed_write(inode);
1489 return ret ? ret : copied;
1490}
1491
1492/*
1493 * bmap() is special. It gets used by applications such as lilo and by
1494 * the swapper to find the on-disk block of a specific piece of data.
1495 *
1496 * Naturally, this is dangerous if the block concerned is still in the
1497 * journal. If somebody makes a swapfile on an ext3 data-journaling
1498 * filesystem and enables swap, then they may get a nasty shock when the
1499 * data getting swapped to that swapfile suddenly gets overwritten by
1500 * the original zero's written out previously to the journal and
1501 * awaiting writeback in the kernel's buffer cache.
1502 *
1503 * So, if we see any bmap calls here on a modified, data-journaled file,
1504 * take extra steps to flush any blocks which might be in the cache.
1505 */
1506static sector_t ext3_bmap(struct address_space *mapping, sector_t block)
1507{
1508 struct inode *inode = mapping->host;
1509 journal_t *journal;
1510 int err;
1511
1512 if (ext3_test_inode_state(inode, EXT3_STATE_JDATA)) {
1513 /*
1514 * This is a REALLY heavyweight approach, but the use of
1515 * bmap on dirty files is expected to be extremely rare:
1516 * only if we run lilo or swapon on a freshly made file
1517 * do we expect this to happen.
1518 *
1519 * (bmap requires CAP_SYS_RAWIO so this does not
1520 * represent an unprivileged user DOS attack --- we'd be
1521 * in trouble if mortal users could trigger this path at
1522 * will.)
1523 *
1524 * NB. EXT3_STATE_JDATA is not set on files other than
1525 * regular files. If somebody wants to bmap a directory
1526 * or symlink and gets confused because the buffer
1527 * hasn't yet been flushed to disk, they deserve
1528 * everything they get.
1529 */
1530
1531 ext3_clear_inode_state(inode, EXT3_STATE_JDATA);
1532 journal = EXT3_JOURNAL(inode);
1533 journal_lock_updates(journal);
1534 err = journal_flush(journal);
1535 journal_unlock_updates(journal);
1536
1537 if (err)
1538 return 0;
1539 }
1540
1541 return generic_block_bmap(mapping,block,ext3_get_block);
1542}
1543
1544static int bget_one(handle_t *handle, struct buffer_head *bh)
1545{
1546 get_bh(bh);
1547 return 0;
1548}
1549
1550static int bput_one(handle_t *handle, struct buffer_head *bh)
1551{
1552 put_bh(bh);
1553 return 0;
1554}
1555
1556static int buffer_unmapped(handle_t *handle, struct buffer_head *bh)
1557{
1558 return !buffer_mapped(bh);
1559}
1560
1561/*
1562 * Note that whenever we need to map blocks we start a transaction even if
1563 * we're not journalling data. This is to preserve ordering: any hole
1564 * instantiation within __block_write_full_page -> ext3_get_block() should be
1565 * journalled along with the data so we don't crash and then get metadata which
1566 * refers to old data.
1567 *
1568 * In all journalling modes block_write_full_page() will start the I/O.
1569 *
1570 * We don't honour synchronous mounts for writepage(). That would be
1571 * disastrous. Any write() or metadata operation will sync the fs for
1572 * us.
1573 */
1574static int ext3_ordered_writepage(struct page *page,
1575 struct writeback_control *wbc)
1576{
1577 struct inode *inode = page->mapping->host;
1578 struct buffer_head *page_bufs;
1579 handle_t *handle = NULL;
1580 int ret = 0;
1581 int err;
1582
1583 J_ASSERT(PageLocked(page));
1584 /*
1585 * We don't want to warn for emergency remount. The condition is
1586 * ordered to avoid dereferencing inode->i_sb in non-error case to
1587 * avoid slow-downs.
1588 */
1589 WARN_ON_ONCE(IS_RDONLY(inode) &&
1590 !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ERROR_FS));
1591
1592 /*
1593 * We give up here if we're reentered, because it might be for a
1594 * different filesystem.
1595 */
1596 if (ext3_journal_current_handle())
1597 goto out_fail;
1598
1599 trace_ext3_ordered_writepage(page);
1600 if (!page_has_buffers(page)) {
1601 create_empty_buffers(page, inode->i_sb->s_blocksize,
1602 (1 << BH_Dirty)|(1 << BH_Uptodate));
1603 page_bufs = page_buffers(page);
1604 } else {
1605 page_bufs = page_buffers(page);
1606 if (!walk_page_buffers(NULL, page_bufs, 0, PAGE_CACHE_SIZE,
1607 NULL, buffer_unmapped)) {
1608 /* Provide NULL get_block() to catch bugs if buffers
1609 * weren't really mapped */
1610 return block_write_full_page(page, NULL, wbc);
1611 }
1612 }
1613 handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
1614
1615 if (IS_ERR(handle)) {
1616 ret = PTR_ERR(handle);
1617 goto out_fail;
1618 }
1619
1620 walk_page_buffers(handle, page_bufs, 0,
1621 PAGE_CACHE_SIZE, NULL, bget_one);
1622
1623 ret = block_write_full_page(page, ext3_get_block, wbc);
1624
1625 /*
1626 * The page can become unlocked at any point now, and
1627 * truncate can then come in and change things. So we
1628 * can't touch *page from now on. But *page_bufs is
1629 * safe due to elevated refcount.
1630 */
1631
1632 /*
1633 * And attach them to the current transaction. But only if
1634 * block_write_full_page() succeeded. Otherwise they are unmapped,
1635 * and generally junk.
1636 */
1637 if (ret == 0)
1638 ret = walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE,
1639 NULL, journal_dirty_data_fn);
1640 walk_page_buffers(handle, page_bufs, 0,
1641 PAGE_CACHE_SIZE, NULL, bput_one);
1642 err = ext3_journal_stop(handle);
1643 if (!ret)
1644 ret = err;
1645 return ret;
1646
1647out_fail:
1648 redirty_page_for_writepage(wbc, page);
1649 unlock_page(page);
1650 return ret;
1651}
1652
1653static int ext3_writeback_writepage(struct page *page,
1654 struct writeback_control *wbc)
1655{
1656 struct inode *inode = page->mapping->host;
1657 handle_t *handle = NULL;
1658 int ret = 0;
1659 int err;
1660
1661 J_ASSERT(PageLocked(page));
1662 /*
1663 * We don't want to warn for emergency remount. The condition is
1664 * ordered to avoid dereferencing inode->i_sb in non-error case to
1665 * avoid slow-downs.
1666 */
1667 WARN_ON_ONCE(IS_RDONLY(inode) &&
1668 !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ERROR_FS));
1669
1670 if (ext3_journal_current_handle())
1671 goto out_fail;
1672
1673 trace_ext3_writeback_writepage(page);
1674 if (page_has_buffers(page)) {
1675 if (!walk_page_buffers(NULL, page_buffers(page), 0,
1676 PAGE_CACHE_SIZE, NULL, buffer_unmapped)) {
1677 /* Provide NULL get_block() to catch bugs if buffers
1678 * weren't really mapped */
1679 return block_write_full_page(page, NULL, wbc);
1680 }
1681 }
1682
1683 handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
1684 if (IS_ERR(handle)) {
1685 ret = PTR_ERR(handle);
1686 goto out_fail;
1687 }
1688
1689 ret = block_write_full_page(page, ext3_get_block, wbc);
1690
1691 err = ext3_journal_stop(handle);
1692 if (!ret)
1693 ret = err;
1694 return ret;
1695
1696out_fail:
1697 redirty_page_for_writepage(wbc, page);
1698 unlock_page(page);
1699 return ret;
1700}
1701
1702static int ext3_journalled_writepage(struct page *page,
1703 struct writeback_control *wbc)
1704{
1705 struct inode *inode = page->mapping->host;
1706 handle_t *handle = NULL;
1707 int ret = 0;
1708 int err;
1709
1710 J_ASSERT(PageLocked(page));
1711 /*
1712 * We don't want to warn for emergency remount. The condition is
1713 * ordered to avoid dereferencing inode->i_sb in non-error case to
1714 * avoid slow-downs.
1715 */
1716 WARN_ON_ONCE(IS_RDONLY(inode) &&
1717 !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ERROR_FS));
1718
1719 if (ext3_journal_current_handle())
1720 goto no_write;
1721
1722 trace_ext3_journalled_writepage(page);
1723 handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
1724 if (IS_ERR(handle)) {
1725 ret = PTR_ERR(handle);
1726 goto no_write;
1727 }
1728
1729 if (!page_has_buffers(page) || PageChecked(page)) {
1730 /*
1731 * It's mmapped pagecache. Add buffers and journal it. There
1732 * doesn't seem much point in redirtying the page here.
1733 */
1734 ClearPageChecked(page);
1735 ret = __block_write_begin(page, 0, PAGE_CACHE_SIZE,
1736 ext3_get_block);
1737 if (ret != 0) {
1738 ext3_journal_stop(handle);
1739 goto out_unlock;
1740 }
1741 ret = walk_page_buffers(handle, page_buffers(page), 0,
1742 PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
1743
1744 err = walk_page_buffers(handle, page_buffers(page), 0,
1745 PAGE_CACHE_SIZE, NULL, write_end_fn);
1746 if (ret == 0)
1747 ret = err;
1748 ext3_set_inode_state(inode, EXT3_STATE_JDATA);
1749 atomic_set(&EXT3_I(inode)->i_datasync_tid,
1750 handle->h_transaction->t_tid);
1751 unlock_page(page);
1752 } else {
1753 /*
1754 * It may be a page full of checkpoint-mode buffers. We don't
1755 * really know unless we go poke around in the buffer_heads.
1756 * But block_write_full_page will do the right thing.
1757 */
1758 ret = block_write_full_page(page, ext3_get_block, wbc);
1759 }
1760 err = ext3_journal_stop(handle);
1761 if (!ret)
1762 ret = err;
1763out:
1764 return ret;
1765
1766no_write:
1767 redirty_page_for_writepage(wbc, page);
1768out_unlock:
1769 unlock_page(page);
1770 goto out;
1771}
1772
1773static int ext3_readpage(struct file *file, struct page *page)
1774{
1775 trace_ext3_readpage(page);
1776 return mpage_readpage(page, ext3_get_block);
1777}
1778
1779static int
1780ext3_readpages(struct file *file, struct address_space *mapping,
1781 struct list_head *pages, unsigned nr_pages)
1782{
1783 return mpage_readpages(mapping, pages, nr_pages, ext3_get_block);
1784}
1785
1786static void ext3_invalidatepage(struct page *page, unsigned int offset,
1787 unsigned int length)
1788{
1789 journal_t *journal = EXT3_JOURNAL(page->mapping->host);
1790
1791 trace_ext3_invalidatepage(page, offset, length);
1792
1793 /*
1794 * If it's a full truncate we just forget about the pending dirtying
1795 */
1796 if (offset == 0 && length == PAGE_CACHE_SIZE)
1797 ClearPageChecked(page);
1798
1799 journal_invalidatepage(journal, page, offset, length);
1800}
1801
1802static int ext3_releasepage(struct page *page, gfp_t wait)
1803{
1804 journal_t *journal = EXT3_JOURNAL(page->mapping->host);
1805
1806 trace_ext3_releasepage(page);
1807 WARN_ON(PageChecked(page));
1808 if (!page_has_buffers(page))
1809 return 0;
1810 return journal_try_to_free_buffers(journal, page, wait);
1811}
1812
1813/*
1814 * If the O_DIRECT write will extend the file then add this inode to the
1815 * orphan list. So recovery will truncate it back to the original size
1816 * if the machine crashes during the write.
1817 *
1818 * If the O_DIRECT write is intantiating holes inside i_size and the machine
1819 * crashes then stale disk data _may_ be exposed inside the file. But current
1820 * VFS code falls back into buffered path in that case so we are safe.
1821 */
1822static ssize_t ext3_direct_IO(int rw, struct kiocb *iocb,
1823 const struct iovec *iov, loff_t offset,
1824 unsigned long nr_segs)
1825{
1826 struct file *file = iocb->ki_filp;
1827 struct inode *inode = file->f_mapping->host;
1828 struct ext3_inode_info *ei = EXT3_I(inode);
1829 handle_t *handle;
1830 ssize_t ret;
1831 int orphan = 0;
1832 size_t count = iov_length(iov, nr_segs);
1833 int retries = 0;
1834
1835 trace_ext3_direct_IO_enter(inode, offset, iov_length(iov, nr_segs), rw);
1836
1837 if (rw == WRITE) {
1838 loff_t final_size = offset + count;
1839
1840 if (final_size > inode->i_size) {
1841 /* Credits for sb + inode write */
1842 handle = ext3_journal_start(inode, 2);
1843 if (IS_ERR(handle)) {
1844 ret = PTR_ERR(handle);
1845 goto out;
1846 }
1847 ret = ext3_orphan_add(handle, inode);
1848 if (ret) {
1849 ext3_journal_stop(handle);
1850 goto out;
1851 }
1852 orphan = 1;
1853 ei->i_disksize = inode->i_size;
1854 ext3_journal_stop(handle);
1855 }
1856 }
1857
1858retry:
1859 ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
1860 ext3_get_block);
1861 /*
1862 * In case of error extending write may have instantiated a few
1863 * blocks outside i_size. Trim these off again.
1864 */
1865 if (unlikely((rw & WRITE) && ret < 0)) {
1866 loff_t isize = i_size_read(inode);
1867 loff_t end = offset + iov_length(iov, nr_segs);
1868
1869 if (end > isize)
1870 ext3_truncate_failed_direct_write(inode);
1871 }
1872 if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
1873 goto retry;
1874
1875 if (orphan) {
1876 int err;
1877
1878 /* Credits for sb + inode write */
1879 handle = ext3_journal_start(inode, 2);
1880 if (IS_ERR(handle)) {
1881 /* This is really bad luck. We've written the data
1882 * but cannot extend i_size. Truncate allocated blocks
1883 * and pretend the write failed... */
1884 ext3_truncate_failed_direct_write(inode);
1885 ret = PTR_ERR(handle);
1886 if (inode->i_nlink)
1887 ext3_orphan_del(NULL, inode);
1888 goto out;
1889 }
1890 if (inode->i_nlink)
1891 ext3_orphan_del(handle, inode);
1892 if (ret > 0) {
1893 loff_t end = offset + ret;
1894 if (end > inode->i_size) {
1895 ei->i_disksize = end;
1896 i_size_write(inode, end);
1897 /*
1898 * We're going to return a positive `ret'
1899 * here due to non-zero-length I/O, so there's
1900 * no way of reporting error returns from
1901 * ext3_mark_inode_dirty() to userspace. So
1902 * ignore it.
1903 */
1904 ext3_mark_inode_dirty(handle, inode);
1905 }
1906 }
1907 err = ext3_journal_stop(handle);
1908 if (ret == 0)
1909 ret = err;
1910 }
1911out:
1912 trace_ext3_direct_IO_exit(inode, offset,
1913 iov_length(iov, nr_segs), rw, ret);
1914 return ret;
1915}
1916
1917/*
1918 * Pages can be marked dirty completely asynchronously from ext3's journalling
1919 * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do
1920 * much here because ->set_page_dirty is called under VFS locks. The page is
1921 * not necessarily locked.
1922 *
1923 * We cannot just dirty the page and leave attached buffers clean, because the
1924 * buffers' dirty state is "definitive". We cannot just set the buffers dirty
1925 * or jbddirty because all the journalling code will explode.
1926 *
1927 * So what we do is to mark the page "pending dirty" and next time writepage
1928 * is called, propagate that into the buffers appropriately.
1929 */
1930static int ext3_journalled_set_page_dirty(struct page *page)
1931{
1932 SetPageChecked(page);
1933 return __set_page_dirty_nobuffers(page);
1934}
1935
1936static const struct address_space_operations ext3_ordered_aops = {
1937 .readpage = ext3_readpage,
1938 .readpages = ext3_readpages,
1939 .writepage = ext3_ordered_writepage,
1940 .write_begin = ext3_write_begin,
1941 .write_end = ext3_ordered_write_end,
1942 .bmap = ext3_bmap,
1943 .invalidatepage = ext3_invalidatepage,
1944 .releasepage = ext3_releasepage,
1945 .direct_IO = ext3_direct_IO,
1946 .migratepage = buffer_migrate_page,
1947 .is_partially_uptodate = block_is_partially_uptodate,
1948 .is_dirty_writeback = buffer_check_dirty_writeback,
1949 .error_remove_page = generic_error_remove_page,
1950};
1951
1952static const struct address_space_operations ext3_writeback_aops = {
1953 .readpage = ext3_readpage,
1954 .readpages = ext3_readpages,
1955 .writepage = ext3_writeback_writepage,
1956 .write_begin = ext3_write_begin,
1957 .write_end = ext3_writeback_write_end,
1958 .bmap = ext3_bmap,
1959 .invalidatepage = ext3_invalidatepage,
1960 .releasepage = ext3_releasepage,
1961 .direct_IO = ext3_direct_IO,
1962 .migratepage = buffer_migrate_page,
1963 .is_partially_uptodate = block_is_partially_uptodate,
1964 .error_remove_page = generic_error_remove_page,
1965};
1966
1967static const struct address_space_operations ext3_journalled_aops = {
1968 .readpage = ext3_readpage,
1969 .readpages = ext3_readpages,
1970 .writepage = ext3_journalled_writepage,
1971 .write_begin = ext3_write_begin,
1972 .write_end = ext3_journalled_write_end,
1973 .set_page_dirty = ext3_journalled_set_page_dirty,
1974 .bmap = ext3_bmap,
1975 .invalidatepage = ext3_invalidatepage,
1976 .releasepage = ext3_releasepage,
1977 .is_partially_uptodate = block_is_partially_uptodate,
1978 .error_remove_page = generic_error_remove_page,
1979};
1980
1981void ext3_set_aops(struct inode *inode)
1982{
1983 if (ext3_should_order_data(inode))
1984 inode->i_mapping->a_ops = &ext3_ordered_aops;
1985 else if (ext3_should_writeback_data(inode))
1986 inode->i_mapping->a_ops = &ext3_writeback_aops;
1987 else
1988 inode->i_mapping->a_ops = &ext3_journalled_aops;
1989}
1990
1991/*
1992 * ext3_block_truncate_page() zeroes out a mapping from file offset `from'
1993 * up to the end of the block which corresponds to `from'.
1994 * This required during truncate. We need to physically zero the tail end
1995 * of that block so it doesn't yield old data if the file is later grown.
1996 */
1997static int ext3_block_truncate_page(struct inode *inode, loff_t from)
1998{
1999 ext3_fsblk_t index = from >> PAGE_CACHE_SHIFT;
2000 unsigned offset = from & (PAGE_CACHE_SIZE - 1);
2001 unsigned blocksize, iblock, length, pos;
2002 struct page *page;
2003 handle_t *handle = NULL;
2004 struct buffer_head *bh;
2005 int err = 0;
2006
2007 /* Truncated on block boundary - nothing to do */
2008 blocksize = inode->i_sb->s_blocksize;
2009 if ((from & (blocksize - 1)) == 0)
2010 return 0;
2011
2012 page = grab_cache_page(inode->i_mapping, index);
2013 if (!page)
2014 return -ENOMEM;
2015 length = blocksize - (offset & (blocksize - 1));
2016 iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
2017
2018 if (!page_has_buffers(page))
2019 create_empty_buffers(page, blocksize, 0);
2020
2021 /* Find the buffer that contains "offset" */
2022 bh = page_buffers(page);
2023 pos = blocksize;
2024 while (offset >= pos) {
2025 bh = bh->b_this_page;
2026 iblock++;
2027 pos += blocksize;
2028 }
2029
2030 err = 0;
2031 if (buffer_freed(bh)) {
2032 BUFFER_TRACE(bh, "freed: skip");
2033 goto unlock;
2034 }
2035
2036 if (!buffer_mapped(bh)) {
2037 BUFFER_TRACE(bh, "unmapped");
2038 ext3_get_block(inode, iblock, bh, 0);
2039 /* unmapped? It's a hole - nothing to do */
2040 if (!buffer_mapped(bh)) {
2041 BUFFER_TRACE(bh, "still unmapped");
2042 goto unlock;
2043 }
2044 }
2045
2046 /* Ok, it's mapped. Make sure it's up-to-date */
2047 if (PageUptodate(page))
2048 set_buffer_uptodate(bh);
2049
2050 if (!bh_uptodate_or_lock(bh)) {
2051 err = bh_submit_read(bh);
2052 /* Uhhuh. Read error. Complain and punt. */
2053 if (err)
2054 goto unlock;
2055 }
2056
2057 /* data=writeback mode doesn't need transaction to zero-out data */
2058 if (!ext3_should_writeback_data(inode)) {
2059 /* We journal at most one block */
2060 handle = ext3_journal_start(inode, 1);
2061 if (IS_ERR(handle)) {
2062 clear_highpage(page);
2063 flush_dcache_page(page);
2064 err = PTR_ERR(handle);
2065 goto unlock;
2066 }
2067 }
2068
2069 if (ext3_should_journal_data(inode)) {
2070 BUFFER_TRACE(bh, "get write access");
2071 err = ext3_journal_get_write_access(handle, bh);
2072 if (err)
2073 goto stop;
2074 }
2075
2076 zero_user(page, offset, length);
2077 BUFFER_TRACE(bh, "zeroed end of block");
2078
2079 err = 0;
2080 if (ext3_should_journal_data(inode)) {
2081 err = ext3_journal_dirty_metadata(handle, bh);
2082 } else {
2083 if (ext3_should_order_data(inode))
2084 err = ext3_journal_dirty_data(handle, bh);
2085 mark_buffer_dirty(bh);
2086 }
2087stop:
2088 if (handle)
2089 ext3_journal_stop(handle);
2090
2091unlock:
2092 unlock_page(page);
2093 page_cache_release(page);
2094 return err;
2095}
2096
2097/*
2098 * Probably it should be a library function... search for first non-zero word
2099 * or memcmp with zero_page, whatever is better for particular architecture.
2100 * Linus?
2101 */
2102static inline int all_zeroes(__le32 *p, __le32 *q)
2103{
2104 while (p < q)
2105 if (*p++)
2106 return 0;
2107 return 1;
2108}
2109
2110/**
2111 * ext3_find_shared - find the indirect blocks for partial truncation.
2112 * @inode: inode in question
2113 * @depth: depth of the affected branch
2114 * @offsets: offsets of pointers in that branch (see ext3_block_to_path)
2115 * @chain: place to store the pointers to partial indirect blocks
2116 * @top: place to the (detached) top of branch
2117 *
2118 * This is a helper function used by ext3_truncate().
2119 *
2120 * When we do truncate() we may have to clean the ends of several
2121 * indirect blocks but leave the blocks themselves alive. Block is
2122 * partially truncated if some data below the new i_size is referred
2123 * from it (and it is on the path to the first completely truncated
2124 * data block, indeed). We have to free the top of that path along
2125 * with everything to the right of the path. Since no allocation
2126 * past the truncation point is possible until ext3_truncate()
2127 * finishes, we may safely do the latter, but top of branch may
2128 * require special attention - pageout below the truncation point
2129 * might try to populate it.
2130 *
2131 * We atomically detach the top of branch from the tree, store the
2132 * block number of its root in *@top, pointers to buffer_heads of
2133 * partially truncated blocks - in @chain[].bh and pointers to
2134 * their last elements that should not be removed - in
2135 * @chain[].p. Return value is the pointer to last filled element
2136 * of @chain.
2137 *
2138 * The work left to caller to do the actual freeing of subtrees:
2139 * a) free the subtree starting from *@top
2140 * b) free the subtrees whose roots are stored in
2141 * (@chain[i].p+1 .. end of @chain[i].bh->b_data)
2142 * c) free the subtrees growing from the inode past the @chain[0].
2143 * (no partially truncated stuff there). */
2144
2145static Indirect *ext3_find_shared(struct inode *inode, int depth,
2146 int offsets[4], Indirect chain[4], __le32 *top)
2147{
2148 Indirect *partial, *p;
2149 int k, err;
2150
2151 *top = 0;
2152 /* Make k index the deepest non-null offset + 1 */
2153 for (k = depth; k > 1 && !offsets[k-1]; k--)
2154 ;
2155 partial = ext3_get_branch(inode, k, offsets, chain, &err);
2156 /* Writer: pointers */
2157 if (!partial)
2158 partial = chain + k-1;
2159 /*
2160 * If the branch acquired continuation since we've looked at it -
2161 * fine, it should all survive and (new) top doesn't belong to us.
2162 */
2163 if (!partial->key && *partial->p)
2164 /* Writer: end */
2165 goto no_top;
2166 for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
2167 ;
2168 /*
2169 * OK, we've found the last block that must survive. The rest of our
2170 * branch should be detached before unlocking. However, if that rest
2171 * of branch is all ours and does not grow immediately from the inode
2172 * it's easier to cheat and just decrement partial->p.
2173 */
2174 if (p == chain + k - 1 && p > chain) {
2175 p->p--;
2176 } else {
2177 *top = *p->p;
2178 /* Nope, don't do this in ext3. Must leave the tree intact */
2179#if 0
2180 *p->p = 0;
2181#endif
2182 }
2183 /* Writer: end */
2184
2185 while(partial > p) {
2186 brelse(partial->bh);
2187 partial--;
2188 }
2189no_top:
2190 return partial;
2191}
2192
2193/*
2194 * Zero a number of block pointers in either an inode or an indirect block.
2195 * If we restart the transaction we must again get write access to the
2196 * indirect block for further modification.
2197 *
2198 * We release `count' blocks on disk, but (last - first) may be greater
2199 * than `count' because there can be holes in there.
2200 */
2201static void ext3_clear_blocks(handle_t *handle, struct inode *inode,
2202 struct buffer_head *bh, ext3_fsblk_t block_to_free,
2203 unsigned long count, __le32 *first, __le32 *last)
2204{
2205 __le32 *p;
2206 if (try_to_extend_transaction(handle, inode)) {
2207 if (bh) {
2208 BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
2209 if (ext3_journal_dirty_metadata(handle, bh))
2210 return;
2211 }
2212 ext3_mark_inode_dirty(handle, inode);
2213 truncate_restart_transaction(handle, inode);
2214 if (bh) {
2215 BUFFER_TRACE(bh, "retaking write access");
2216 if (ext3_journal_get_write_access(handle, bh))
2217 return;
2218 }
2219 }
2220
2221 /*
2222 * Any buffers which are on the journal will be in memory. We find
2223 * them on the hash table so journal_revoke() will run journal_forget()
2224 * on them. We've already detached each block from the file, so
2225 * bforget() in journal_forget() should be safe.
2226 *
2227 * AKPM: turn on bforget in journal_forget()!!!
2228 */
2229 for (p = first; p < last; p++) {
2230 u32 nr = le32_to_cpu(*p);
2231 if (nr) {
2232 struct buffer_head *bh;
2233
2234 *p = 0;
2235 bh = sb_find_get_block(inode->i_sb, nr);
2236 ext3_forget(handle, 0, inode, bh, nr);
2237 }
2238 }
2239
2240 ext3_free_blocks(handle, inode, block_to_free, count);
2241}
2242
2243/**
2244 * ext3_free_data - free a list of data blocks
2245 * @handle: handle for this transaction
2246 * @inode: inode we are dealing with
2247 * @this_bh: indirect buffer_head which contains *@first and *@last
2248 * @first: array of block numbers
2249 * @last: points immediately past the end of array
2250 *
2251 * We are freeing all blocks referred from that array (numbers are stored as
2252 * little-endian 32-bit) and updating @inode->i_blocks appropriately.
2253 *
2254 * We accumulate contiguous runs of blocks to free. Conveniently, if these
2255 * blocks are contiguous then releasing them at one time will only affect one
2256 * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
2257 * actually use a lot of journal space.
2258 *
2259 * @this_bh will be %NULL if @first and @last point into the inode's direct
2260 * block pointers.
2261 */
2262static void ext3_free_data(handle_t *handle, struct inode *inode,
2263 struct buffer_head *this_bh,
2264 __le32 *first, __le32 *last)
2265{
2266 ext3_fsblk_t block_to_free = 0; /* Starting block # of a run */
2267 unsigned long count = 0; /* Number of blocks in the run */
2268 __le32 *block_to_free_p = NULL; /* Pointer into inode/ind
2269 corresponding to
2270 block_to_free */
2271 ext3_fsblk_t nr; /* Current block # */
2272 __le32 *p; /* Pointer into inode/ind
2273 for current block */
2274 int err;
2275
2276 if (this_bh) { /* For indirect block */
2277 BUFFER_TRACE(this_bh, "get_write_access");
2278 err = ext3_journal_get_write_access(handle, this_bh);
2279 /* Important: if we can't update the indirect pointers
2280 * to the blocks, we can't free them. */
2281 if (err)
2282 return;
2283 }
2284
2285 for (p = first; p < last; p++) {
2286 nr = le32_to_cpu(*p);
2287 if (nr) {
2288 /* accumulate blocks to free if they're contiguous */
2289 if (count == 0) {
2290 block_to_free = nr;
2291 block_to_free_p = p;
2292 count = 1;
2293 } else if (nr == block_to_free + count) {
2294 count++;
2295 } else {
2296 ext3_clear_blocks(handle, inode, this_bh,
2297 block_to_free,
2298 count, block_to_free_p, p);
2299 block_to_free = nr;
2300 block_to_free_p = p;
2301 count = 1;
2302 }
2303 }
2304 }
2305
2306 if (count > 0)
2307 ext3_clear_blocks(handle, inode, this_bh, block_to_free,
2308 count, block_to_free_p, p);
2309
2310 if (this_bh) {
2311 BUFFER_TRACE(this_bh, "call ext3_journal_dirty_metadata");
2312
2313 /*
2314 * The buffer head should have an attached journal head at this
2315 * point. However, if the data is corrupted and an indirect
2316 * block pointed to itself, it would have been detached when
2317 * the block was cleared. Check for this instead of OOPSing.
2318 */
2319 if (bh2jh(this_bh))
2320 ext3_journal_dirty_metadata(handle, this_bh);
2321 else
2322 ext3_error(inode->i_sb, "ext3_free_data",
2323 "circular indirect block detected, "
2324 "inode=%lu, block=%llu",
2325 inode->i_ino,
2326 (unsigned long long)this_bh->b_blocknr);
2327 }
2328}
2329
2330/**
2331 * ext3_free_branches - free an array of branches
2332 * @handle: JBD handle for this transaction
2333 * @inode: inode we are dealing with
2334 * @parent_bh: the buffer_head which contains *@first and *@last
2335 * @first: array of block numbers
2336 * @last: pointer immediately past the end of array
2337 * @depth: depth of the branches to free
2338 *
2339 * We are freeing all blocks referred from these branches (numbers are
2340 * stored as little-endian 32-bit) and updating @inode->i_blocks
2341 * appropriately.
2342 */
2343static void ext3_free_branches(handle_t *handle, struct inode *inode,
2344 struct buffer_head *parent_bh,
2345 __le32 *first, __le32 *last, int depth)
2346{
2347 ext3_fsblk_t nr;
2348 __le32 *p;
2349
2350 if (is_handle_aborted(handle))
2351 return;
2352
2353 if (depth--) {
2354 struct buffer_head *bh;
2355 int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
2356 p = last;
2357 while (--p >= first) {
2358 nr = le32_to_cpu(*p);
2359 if (!nr)
2360 continue; /* A hole */
2361
2362 /* Go read the buffer for the next level down */
2363 bh = sb_bread(inode->i_sb, nr);
2364
2365 /*
2366 * A read failure? Report error and clear slot
2367 * (should be rare).
2368 */
2369 if (!bh) {
2370 ext3_error(inode->i_sb, "ext3_free_branches",
2371 "Read failure, inode=%lu, block="E3FSBLK,
2372 inode->i_ino, nr);
2373 continue;
2374 }
2375
2376 /* This zaps the entire block. Bottom up. */
2377 BUFFER_TRACE(bh, "free child branches");
2378 ext3_free_branches(handle, inode, bh,
2379 (__le32*)bh->b_data,
2380 (__le32*)bh->b_data + addr_per_block,
2381 depth);
2382
2383 /*
2384 * Everything below this this pointer has been
2385 * released. Now let this top-of-subtree go.
2386 *
2387 * We want the freeing of this indirect block to be
2388 * atomic in the journal with the updating of the
2389 * bitmap block which owns it. So make some room in
2390 * the journal.
2391 *
2392 * We zero the parent pointer *after* freeing its
2393 * pointee in the bitmaps, so if extend_transaction()
2394 * for some reason fails to put the bitmap changes and
2395 * the release into the same transaction, recovery
2396 * will merely complain about releasing a free block,
2397 * rather than leaking blocks.
2398 */
2399 if (is_handle_aborted(handle))
2400 return;
2401 if (try_to_extend_transaction(handle, inode)) {
2402 ext3_mark_inode_dirty(handle, inode);
2403 truncate_restart_transaction(handle, inode);
2404 }
2405
2406 /*
2407 * We've probably journalled the indirect block several
2408 * times during the truncate. But it's no longer
2409 * needed and we now drop it from the transaction via
2410 * journal_revoke().
2411 *
2412 * That's easy if it's exclusively part of this
2413 * transaction. But if it's part of the committing
2414 * transaction then journal_forget() will simply
2415 * brelse() it. That means that if the underlying
2416 * block is reallocated in ext3_get_block(),
2417 * unmap_underlying_metadata() will find this block
2418 * and will try to get rid of it. damn, damn. Thus
2419 * we don't allow a block to be reallocated until
2420 * a transaction freeing it has fully committed.
2421 *
2422 * We also have to make sure journal replay after a
2423 * crash does not overwrite non-journaled data blocks
2424 * with old metadata when the block got reallocated for
2425 * data. Thus we have to store a revoke record for a
2426 * block in the same transaction in which we free the
2427 * block.
2428 */
2429 ext3_forget(handle, 1, inode, bh, bh->b_blocknr);
2430
2431 ext3_free_blocks(handle, inode, nr, 1);
2432
2433 if (parent_bh) {
2434 /*
2435 * The block which we have just freed is
2436 * pointed to by an indirect block: journal it
2437 */
2438 BUFFER_TRACE(parent_bh, "get_write_access");
2439 if (!ext3_journal_get_write_access(handle,
2440 parent_bh)){
2441 *p = 0;
2442 BUFFER_TRACE(parent_bh,
2443 "call ext3_journal_dirty_metadata");
2444 ext3_journal_dirty_metadata(handle,
2445 parent_bh);
2446 }
2447 }
2448 }
2449 } else {
2450 /* We have reached the bottom of the tree. */
2451 BUFFER_TRACE(parent_bh, "free data blocks");
2452 ext3_free_data(handle, inode, parent_bh, first, last);
2453 }
2454}
2455
2456int ext3_can_truncate(struct inode *inode)
2457{
2458 if (S_ISREG(inode->i_mode))
2459 return 1;
2460 if (S_ISDIR(inode->i_mode))
2461 return 1;
2462 if (S_ISLNK(inode->i_mode))
2463 return !ext3_inode_is_fast_symlink(inode);
2464 return 0;
2465}
2466
2467/*
2468 * ext3_truncate()
2469 *
2470 * We block out ext3_get_block() block instantiations across the entire
2471 * transaction, and VFS/VM ensures that ext3_truncate() cannot run
2472 * simultaneously on behalf of the same inode.
2473 *
2474 * As we work through the truncate and commit bits of it to the journal there
2475 * is one core, guiding principle: the file's tree must always be consistent on
2476 * disk. We must be able to restart the truncate after a crash.
2477 *
2478 * The file's tree may be transiently inconsistent in memory (although it
2479 * probably isn't), but whenever we close off and commit a journal transaction,
2480 * the contents of (the filesystem + the journal) must be consistent and
2481 * restartable. It's pretty simple, really: bottom up, right to left (although
2482 * left-to-right works OK too).
2483 *
2484 * Note that at recovery time, journal replay occurs *before* the restart of
2485 * truncate against the orphan inode list.
2486 *
2487 * The committed inode has the new, desired i_size (which is the same as
2488 * i_disksize in this case). After a crash, ext3_orphan_cleanup() will see
2489 * that this inode's truncate did not complete and it will again call
2490 * ext3_truncate() to have another go. So there will be instantiated blocks
2491 * to the right of the truncation point in a crashed ext3 filesystem. But
2492 * that's fine - as long as they are linked from the inode, the post-crash
2493 * ext3_truncate() run will find them and release them.
2494 */
2495void ext3_truncate(struct inode *inode)
2496{
2497 handle_t *handle;
2498 struct ext3_inode_info *ei = EXT3_I(inode);
2499 __le32 *i_data = ei->i_data;
2500 int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
2501 int offsets[4];
2502 Indirect chain[4];
2503 Indirect *partial;
2504 __le32 nr = 0;
2505 int n;
2506 long last_block;
2507 unsigned blocksize = inode->i_sb->s_blocksize;
2508
2509 trace_ext3_truncate_enter(inode);
2510
2511 if (!ext3_can_truncate(inode))
2512 goto out_notrans;
2513
2514 if (inode->i_size == 0 && ext3_should_writeback_data(inode))
2515 ext3_set_inode_state(inode, EXT3_STATE_FLUSH_ON_CLOSE);
2516
2517 handle = start_transaction(inode);
2518 if (IS_ERR(handle))
2519 goto out_notrans;
2520
2521 last_block = (inode->i_size + blocksize-1)
2522 >> EXT3_BLOCK_SIZE_BITS(inode->i_sb);
2523 n = ext3_block_to_path(inode, last_block, offsets, NULL);
2524 if (n == 0)
2525 goto out_stop; /* error */
2526
2527 /*
2528 * OK. This truncate is going to happen. We add the inode to the
2529 * orphan list, so that if this truncate spans multiple transactions,
2530 * and we crash, we will resume the truncate when the filesystem
2531 * recovers. It also marks the inode dirty, to catch the new size.
2532 *
2533 * Implication: the file must always be in a sane, consistent
2534 * truncatable state while each transaction commits.
2535 */
2536 if (ext3_orphan_add(handle, inode))
2537 goto out_stop;
2538
2539 /*
2540 * The orphan list entry will now protect us from any crash which
2541 * occurs before the truncate completes, so it is now safe to propagate
2542 * the new, shorter inode size (held for now in i_size) into the
2543 * on-disk inode. We do this via i_disksize, which is the value which
2544 * ext3 *really* writes onto the disk inode.
2545 */
2546 ei->i_disksize = inode->i_size;
2547
2548 /*
2549 * From here we block out all ext3_get_block() callers who want to
2550 * modify the block allocation tree.
2551 */
2552 mutex_lock(&ei->truncate_mutex);
2553
2554 if (n == 1) { /* direct blocks */
2555 ext3_free_data(handle, inode, NULL, i_data+offsets[0],
2556 i_data + EXT3_NDIR_BLOCKS);
2557 goto do_indirects;
2558 }
2559
2560 partial = ext3_find_shared(inode, n, offsets, chain, &nr);
2561 /* Kill the top of shared branch (not detached) */
2562 if (nr) {
2563 if (partial == chain) {
2564 /* Shared branch grows from the inode */
2565 ext3_free_branches(handle, inode, NULL,
2566 &nr, &nr+1, (chain+n-1) - partial);
2567 *partial->p = 0;
2568 /*
2569 * We mark the inode dirty prior to restart,
2570 * and prior to stop. No need for it here.
2571 */
2572 } else {
2573 /* Shared branch grows from an indirect block */
2574 ext3_free_branches(handle, inode, partial->bh,
2575 partial->p,
2576 partial->p+1, (chain+n-1) - partial);
2577 }
2578 }
2579 /* Clear the ends of indirect blocks on the shared branch */
2580 while (partial > chain) {
2581 ext3_free_branches(handle, inode, partial->bh, partial->p + 1,
2582 (__le32*)partial->bh->b_data+addr_per_block,
2583 (chain+n-1) - partial);
2584 BUFFER_TRACE(partial->bh, "call brelse");
2585 brelse (partial->bh);
2586 partial--;
2587 }
2588do_indirects:
2589 /* Kill the remaining (whole) subtrees */
2590 switch (offsets[0]) {
2591 default:
2592 nr = i_data[EXT3_IND_BLOCK];
2593 if (nr) {
2594 ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
2595 i_data[EXT3_IND_BLOCK] = 0;
2596 }
2597 case EXT3_IND_BLOCK:
2598 nr = i_data[EXT3_DIND_BLOCK];
2599 if (nr) {
2600 ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
2601 i_data[EXT3_DIND_BLOCK] = 0;
2602 }
2603 case EXT3_DIND_BLOCK:
2604 nr = i_data[EXT3_TIND_BLOCK];
2605 if (nr) {
2606 ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
2607 i_data[EXT3_TIND_BLOCK] = 0;
2608 }
2609 case EXT3_TIND_BLOCK:
2610 ;
2611 }
2612
2613 ext3_discard_reservation(inode);
2614
2615 mutex_unlock(&ei->truncate_mutex);
2616 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
2617 ext3_mark_inode_dirty(handle, inode);
2618
2619 /*
2620 * In a multi-transaction truncate, we only make the final transaction
2621 * synchronous
2622 */
2623 if (IS_SYNC(inode))
2624 handle->h_sync = 1;
2625out_stop:
2626 /*
2627 * If this was a simple ftruncate(), and the file will remain alive
2628 * then we need to clear up the orphan record which we created above.
2629 * However, if this was a real unlink then we were called by
2630 * ext3_evict_inode(), and we allow that function to clean up the
2631 * orphan info for us.
2632 */
2633 if (inode->i_nlink)
2634 ext3_orphan_del(handle, inode);
2635
2636 ext3_journal_stop(handle);
2637 trace_ext3_truncate_exit(inode);
2638 return;
2639out_notrans:
2640 /*
2641 * Delete the inode from orphan list so that it doesn't stay there
2642 * forever and trigger assertion on umount.
2643 */
2644 if (inode->i_nlink)
2645 ext3_orphan_del(NULL, inode);
2646 trace_ext3_truncate_exit(inode);
2647}
2648
2649static ext3_fsblk_t ext3_get_inode_block(struct super_block *sb,
2650 unsigned long ino, struct ext3_iloc *iloc)
2651{
2652 unsigned long block_group;
2653 unsigned long offset;
2654 ext3_fsblk_t block;
2655 struct ext3_group_desc *gdp;
2656
2657 if (!ext3_valid_inum(sb, ino)) {
2658 /*
2659 * This error is already checked for in namei.c unless we are
2660 * looking at an NFS filehandle, in which case no error
2661 * report is needed
2662 */
2663 return 0;
2664 }
2665
2666 block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
2667 gdp = ext3_get_group_desc(sb, block_group, NULL);
2668 if (!gdp)
2669 return 0;
2670 /*
2671 * Figure out the offset within the block group inode table
2672 */
2673 offset = ((ino - 1) % EXT3_INODES_PER_GROUP(sb)) *
2674 EXT3_INODE_SIZE(sb);
2675 block = le32_to_cpu(gdp->bg_inode_table) +
2676 (offset >> EXT3_BLOCK_SIZE_BITS(sb));
2677
2678 iloc->block_group = block_group;
2679 iloc->offset = offset & (EXT3_BLOCK_SIZE(sb) - 1);
2680 return block;
2681}
2682
2683/*
2684 * ext3_get_inode_loc returns with an extra refcount against the inode's
2685 * underlying buffer_head on success. If 'in_mem' is true, we have all
2686 * data in memory that is needed to recreate the on-disk version of this
2687 * inode.
2688 */
2689static int __ext3_get_inode_loc(struct inode *inode,
2690 struct ext3_iloc *iloc, int in_mem)
2691{
2692 ext3_fsblk_t block;
2693 struct buffer_head *bh;
2694
2695 block = ext3_get_inode_block(inode->i_sb, inode->i_ino, iloc);
2696 if (!block)
2697 return -EIO;
2698
2699 bh = sb_getblk(inode->i_sb, block);
2700 if (unlikely(!bh)) {
2701 ext3_error (inode->i_sb, "ext3_get_inode_loc",
2702 "unable to read inode block - "
2703 "inode=%lu, block="E3FSBLK,
2704 inode->i_ino, block);
2705 return -ENOMEM;
2706 }
2707 if (!buffer_uptodate(bh)) {
2708 lock_buffer(bh);
2709
2710 /*
2711 * If the buffer has the write error flag, we have failed
2712 * to write out another inode in the same block. In this
2713 * case, we don't have to read the block because we may
2714 * read the old inode data successfully.
2715 */
2716 if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
2717 set_buffer_uptodate(bh);
2718
2719 if (buffer_uptodate(bh)) {
2720 /* someone brought it uptodate while we waited */
2721 unlock_buffer(bh);
2722 goto has_buffer;
2723 }
2724
2725 /*
2726 * If we have all information of the inode in memory and this
2727 * is the only valid inode in the block, we need not read the
2728 * block.
2729 */
2730 if (in_mem) {
2731 struct buffer_head *bitmap_bh;
2732 struct ext3_group_desc *desc;
2733 int inodes_per_buffer;
2734 int inode_offset, i;
2735 int block_group;
2736 int start;
2737
2738 block_group = (inode->i_ino - 1) /
2739 EXT3_INODES_PER_GROUP(inode->i_sb);
2740 inodes_per_buffer = bh->b_size /
2741 EXT3_INODE_SIZE(inode->i_sb);
2742 inode_offset = ((inode->i_ino - 1) %
2743 EXT3_INODES_PER_GROUP(inode->i_sb));
2744 start = inode_offset & ~(inodes_per_buffer - 1);
2745
2746 /* Is the inode bitmap in cache? */
2747 desc = ext3_get_group_desc(inode->i_sb,
2748 block_group, NULL);
2749 if (!desc)
2750 goto make_io;
2751
2752 bitmap_bh = sb_getblk(inode->i_sb,
2753 le32_to_cpu(desc->bg_inode_bitmap));
2754 if (unlikely(!bitmap_bh))
2755 goto make_io;
2756
2757 /*
2758 * If the inode bitmap isn't in cache then the
2759 * optimisation may end up performing two reads instead
2760 * of one, so skip it.
2761 */
2762 if (!buffer_uptodate(bitmap_bh)) {
2763 brelse(bitmap_bh);
2764 goto make_io;
2765 }
2766 for (i = start; i < start + inodes_per_buffer; i++) {
2767 if (i == inode_offset)
2768 continue;
2769 if (ext3_test_bit(i, bitmap_bh->b_data))
2770 break;
2771 }
2772 brelse(bitmap_bh);
2773 if (i == start + inodes_per_buffer) {
2774 /* all other inodes are free, so skip I/O */
2775 memset(bh->b_data, 0, bh->b_size);
2776 set_buffer_uptodate(bh);
2777 unlock_buffer(bh);
2778 goto has_buffer;
2779 }
2780 }
2781
2782make_io:
2783 /*
2784 * There are other valid inodes in the buffer, this inode
2785 * has in-inode xattrs, or we don't have this inode in memory.
2786 * Read the block from disk.
2787 */
2788 trace_ext3_load_inode(inode);
2789 get_bh(bh);
2790 bh->b_end_io = end_buffer_read_sync;
2791 submit_bh(READ | REQ_META | REQ_PRIO, bh);
2792 wait_on_buffer(bh);
2793 if (!buffer_uptodate(bh)) {
2794 ext3_error(inode->i_sb, "ext3_get_inode_loc",
2795 "unable to read inode block - "
2796 "inode=%lu, block="E3FSBLK,
2797 inode->i_ino, block);
2798 brelse(bh);
2799 return -EIO;
2800 }
2801 }
2802has_buffer:
2803 iloc->bh = bh;
2804 return 0;
2805}
2806
2807int ext3_get_inode_loc(struct inode *inode, struct ext3_iloc *iloc)
2808{
2809 /* We have all inode data except xattrs in memory here. */
2810 return __ext3_get_inode_loc(inode, iloc,
2811 !ext3_test_inode_state(inode, EXT3_STATE_XATTR));
2812}
2813
2814void ext3_set_inode_flags(struct inode *inode)
2815{
2816 unsigned int flags = EXT3_I(inode)->i_flags;
2817
2818 inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
2819 if (flags & EXT3_SYNC_FL)
2820 inode->i_flags |= S_SYNC;
2821 if (flags & EXT3_APPEND_FL)
2822 inode->i_flags |= S_APPEND;
2823 if (flags & EXT3_IMMUTABLE_FL)
2824 inode->i_flags |= S_IMMUTABLE;
2825 if (flags & EXT3_NOATIME_FL)
2826 inode->i_flags |= S_NOATIME;
2827 if (flags & EXT3_DIRSYNC_FL)
2828 inode->i_flags |= S_DIRSYNC;
2829}
2830
2831/* Propagate flags from i_flags to EXT3_I(inode)->i_flags */
2832void ext3_get_inode_flags(struct ext3_inode_info *ei)
2833{
2834 unsigned int flags = ei->vfs_inode.i_flags;
2835
2836 ei->i_flags &= ~(EXT3_SYNC_FL|EXT3_APPEND_FL|
2837 EXT3_IMMUTABLE_FL|EXT3_NOATIME_FL|EXT3_DIRSYNC_FL);
2838 if (flags & S_SYNC)
2839 ei->i_flags |= EXT3_SYNC_FL;
2840 if (flags & S_APPEND)
2841 ei->i_flags |= EXT3_APPEND_FL;
2842 if (flags & S_IMMUTABLE)
2843 ei->i_flags |= EXT3_IMMUTABLE_FL;
2844 if (flags & S_NOATIME)
2845 ei->i_flags |= EXT3_NOATIME_FL;
2846 if (flags & S_DIRSYNC)
2847 ei->i_flags |= EXT3_DIRSYNC_FL;
2848}
2849
2850struct inode *ext3_iget(struct super_block *sb, unsigned long ino)
2851{
2852 struct ext3_iloc iloc;
2853 struct ext3_inode *raw_inode;
2854 struct ext3_inode_info *ei;
2855 struct buffer_head *bh;
2856 struct inode *inode;
2857 journal_t *journal = EXT3_SB(sb)->s_journal;
2858 transaction_t *transaction;
2859 long ret;
2860 int block;
2861 uid_t i_uid;
2862 gid_t i_gid;
2863
2864 inode = iget_locked(sb, ino);
2865 if (!inode)
2866 return ERR_PTR(-ENOMEM);
2867 if (!(inode->i_state & I_NEW))
2868 return inode;
2869
2870 ei = EXT3_I(inode);
2871 ei->i_block_alloc_info = NULL;
2872
2873 ret = __ext3_get_inode_loc(inode, &iloc, 0);
2874 if (ret < 0)
2875 goto bad_inode;
2876 bh = iloc.bh;
2877 raw_inode = ext3_raw_inode(&iloc);
2878 inode->i_mode = le16_to_cpu(raw_inode->i_mode);
2879 i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
2880 i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
2881 if(!(test_opt (inode->i_sb, NO_UID32))) {
2882 i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
2883 i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
2884 }
2885 i_uid_write(inode, i_uid);
2886 i_gid_write(inode, i_gid);
2887 set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
2888 inode->i_size = le32_to_cpu(raw_inode->i_size);
2889 inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
2890 inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
2891 inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
2892 inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = inode->i_mtime.tv_nsec = 0;
2893
2894 ei->i_state_flags = 0;
2895 ei->i_dir_start_lookup = 0;
2896 ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
2897 /* We now have enough fields to check if the inode was active or not.
2898 * This is needed because nfsd might try to access dead inodes
2899 * the test is that same one that e2fsck uses
2900 * NeilBrown 1999oct15
2901 */
2902 if (inode->i_nlink == 0) {
2903 if (inode->i_mode == 0 ||
2904 !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ORPHAN_FS)) {
2905 /* this inode is deleted */
2906 brelse (bh);
2907 ret = -ESTALE;
2908 goto bad_inode;
2909 }
2910 /* The only unlinked inodes we let through here have
2911 * valid i_mode and are being read by the orphan
2912 * recovery code: that's fine, we're about to complete
2913 * the process of deleting those. */
2914 }
2915 inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
2916 ei->i_flags = le32_to_cpu(raw_inode->i_flags);
2917#ifdef EXT3_FRAGMENTS
2918 ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
2919 ei->i_frag_no = raw_inode->i_frag;
2920 ei->i_frag_size = raw_inode->i_fsize;
2921#endif
2922 ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
2923 if (!S_ISREG(inode->i_mode)) {
2924 ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
2925 } else {
2926 inode->i_size |=
2927 ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
2928 }
2929 ei->i_disksize = inode->i_size;
2930 inode->i_generation = le32_to_cpu(raw_inode->i_generation);
2931 ei->i_block_group = iloc.block_group;
2932 /*
2933 * NOTE! The in-memory inode i_data array is in little-endian order
2934 * even on big-endian machines: we do NOT byteswap the block numbers!
2935 */
2936 for (block = 0; block < EXT3_N_BLOCKS; block++)
2937 ei->i_data[block] = raw_inode->i_block[block];
2938 INIT_LIST_HEAD(&ei->i_orphan);
2939
2940 /*
2941 * Set transaction id's of transactions that have to be committed
2942 * to finish f[data]sync. We set them to currently running transaction
2943 * as we cannot be sure that the inode or some of its metadata isn't
2944 * part of the transaction - the inode could have been reclaimed and
2945 * now it is reread from disk.
2946 */
2947 if (journal) {
2948 tid_t tid;
2949
2950 spin_lock(&journal->j_state_lock);
2951 if (journal->j_running_transaction)
2952 transaction = journal->j_running_transaction;
2953 else
2954 transaction = journal->j_committing_transaction;
2955 if (transaction)
2956 tid = transaction->t_tid;
2957 else
2958 tid = journal->j_commit_sequence;
2959 spin_unlock(&journal->j_state_lock);
2960 atomic_set(&ei->i_sync_tid, tid);
2961 atomic_set(&ei->i_datasync_tid, tid);
2962 }
2963
2964 if (inode->i_ino >= EXT3_FIRST_INO(inode->i_sb) + 1 &&
2965 EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) {
2966 /*
2967 * When mke2fs creates big inodes it does not zero out
2968 * the unused bytes above EXT3_GOOD_OLD_INODE_SIZE,
2969 * so ignore those first few inodes.
2970 */
2971 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
2972 if (EXT3_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
2973 EXT3_INODE_SIZE(inode->i_sb)) {
2974 brelse (bh);
2975 ret = -EIO;
2976 goto bad_inode;
2977 }
2978 if (ei->i_extra_isize == 0) {
2979 /* The extra space is currently unused. Use it. */
2980 ei->i_extra_isize = sizeof(struct ext3_inode) -
2981 EXT3_GOOD_OLD_INODE_SIZE;
2982 } else {
2983 __le32 *magic = (void *)raw_inode +
2984 EXT3_GOOD_OLD_INODE_SIZE +
2985 ei->i_extra_isize;
2986 if (*magic == cpu_to_le32(EXT3_XATTR_MAGIC))
2987 ext3_set_inode_state(inode, EXT3_STATE_XATTR);
2988 }
2989 } else
2990 ei->i_extra_isize = 0;
2991
2992 if (S_ISREG(inode->i_mode)) {
2993 inode->i_op = &ext3_file_inode_operations;
2994 inode->i_fop = &ext3_file_operations;
2995 ext3_set_aops(inode);
2996 } else if (S_ISDIR(inode->i_mode)) {
2997 inode->i_op = &ext3_dir_inode_operations;
2998 inode->i_fop = &ext3_dir_operations;
2999 } else if (S_ISLNK(inode->i_mode)) {
3000 if (ext3_inode_is_fast_symlink(inode)) {
3001 inode->i_op = &ext3_fast_symlink_inode_operations;
3002 nd_terminate_link(ei->i_data, inode->i_size,
3003 sizeof(ei->i_data) - 1);
3004 } else {
3005 inode->i_op = &ext3_symlink_inode_operations;
3006 ext3_set_aops(inode);
3007 }
3008 } else {
3009 inode->i_op = &ext3_special_inode_operations;
3010 if (raw_inode->i_block[0])
3011 init_special_inode(inode, inode->i_mode,
3012 old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
3013 else
3014 init_special_inode(inode, inode->i_mode,
3015 new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
3016 }
3017 brelse (iloc.bh);
3018 ext3_set_inode_flags(inode);
3019 unlock_new_inode(inode);
3020 return inode;
3021
3022bad_inode:
3023 iget_failed(inode);
3024 return ERR_PTR(ret);
3025}
3026
3027/*
3028 * Post the struct inode info into an on-disk inode location in the
3029 * buffer-cache. This gobbles the caller's reference to the
3030 * buffer_head in the inode location struct.
3031 *
3032 * The caller must have write access to iloc->bh.
3033 */
3034static int ext3_do_update_inode(handle_t *handle,
3035 struct inode *inode,
3036 struct ext3_iloc *iloc)
3037{
3038 struct ext3_inode *raw_inode = ext3_raw_inode(iloc);
3039 struct ext3_inode_info *ei = EXT3_I(inode);
3040 struct buffer_head *bh = iloc->bh;
3041 int err = 0, rc, block;
3042 int need_datasync = 0;
3043 __le32 disksize;
3044 uid_t i_uid;
3045 gid_t i_gid;
3046
3047again:
3048 /* we can't allow multiple procs in here at once, its a bit racey */
3049 lock_buffer(bh);
3050
3051 /* For fields not not tracking in the in-memory inode,
3052 * initialise them to zero for new inodes. */
3053 if (ext3_test_inode_state(inode, EXT3_STATE_NEW))
3054 memset(raw_inode, 0, EXT3_SB(inode->i_sb)->s_inode_size);
3055
3056 ext3_get_inode_flags(ei);
3057 raw_inode->i_mode = cpu_to_le16(inode->i_mode);
3058 i_uid = i_uid_read(inode);
3059 i_gid = i_gid_read(inode);
3060 if(!(test_opt(inode->i_sb, NO_UID32))) {
3061 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
3062 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
3063/*
3064 * Fix up interoperability with old kernels. Otherwise, old inodes get
3065 * re-used with the upper 16 bits of the uid/gid intact
3066 */
3067 if(!ei->i_dtime) {
3068 raw_inode->i_uid_high =
3069 cpu_to_le16(high_16_bits(i_uid));
3070 raw_inode->i_gid_high =
3071 cpu_to_le16(high_16_bits(i_gid));
3072 } else {
3073 raw_inode->i_uid_high = 0;
3074 raw_inode->i_gid_high = 0;
3075 }
3076 } else {
3077 raw_inode->i_uid_low =
3078 cpu_to_le16(fs_high2lowuid(i_uid));
3079 raw_inode->i_gid_low =
3080 cpu_to_le16(fs_high2lowgid(i_gid));
3081 raw_inode->i_uid_high = 0;
3082 raw_inode->i_gid_high = 0;
3083 }
3084 raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
3085 disksize = cpu_to_le32(ei->i_disksize);
3086 if (disksize != raw_inode->i_size) {
3087 need_datasync = 1;
3088 raw_inode->i_size = disksize;
3089 }
3090 raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
3091 raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
3092 raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
3093 raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
3094 raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
3095 raw_inode->i_flags = cpu_to_le32(ei->i_flags);
3096#ifdef EXT3_FRAGMENTS
3097 raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
3098 raw_inode->i_frag = ei->i_frag_no;
3099 raw_inode->i_fsize = ei->i_frag_size;
3100#endif
3101 raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
3102 if (!S_ISREG(inode->i_mode)) {
3103 raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
3104 } else {
3105 disksize = cpu_to_le32(ei->i_disksize >> 32);
3106 if (disksize != raw_inode->i_size_high) {
3107 raw_inode->i_size_high = disksize;
3108 need_datasync = 1;
3109 }
3110 if (ei->i_disksize > 0x7fffffffULL) {
3111 struct super_block *sb = inode->i_sb;
3112 if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
3113 EXT3_FEATURE_RO_COMPAT_LARGE_FILE) ||
3114 EXT3_SB(sb)->s_es->s_rev_level ==
3115 cpu_to_le32(EXT3_GOOD_OLD_REV)) {
3116 /* If this is the first large file
3117 * created, add a flag to the superblock.
3118 */
3119 unlock_buffer(bh);
3120 err = ext3_journal_get_write_access(handle,
3121 EXT3_SB(sb)->s_sbh);
3122 if (err)
3123 goto out_brelse;
3124
3125 ext3_update_dynamic_rev(sb);
3126 EXT3_SET_RO_COMPAT_FEATURE(sb,
3127 EXT3_FEATURE_RO_COMPAT_LARGE_FILE);
3128 handle->h_sync = 1;
3129 err = ext3_journal_dirty_metadata(handle,
3130 EXT3_SB(sb)->s_sbh);
3131 /* get our lock and start over */
3132 goto again;
3133 }
3134 }
3135 }
3136 raw_inode->i_generation = cpu_to_le32(inode->i_generation);
3137 if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
3138 if (old_valid_dev(inode->i_rdev)) {
3139 raw_inode->i_block[0] =
3140 cpu_to_le32(old_encode_dev(inode->i_rdev));
3141 raw_inode->i_block[1] = 0;
3142 } else {
3143 raw_inode->i_block[0] = 0;
3144 raw_inode->i_block[1] =
3145 cpu_to_le32(new_encode_dev(inode->i_rdev));
3146 raw_inode->i_block[2] = 0;
3147 }
3148 } else for (block = 0; block < EXT3_N_BLOCKS; block++)
3149 raw_inode->i_block[block] = ei->i_data[block];
3150
3151 if (ei->i_extra_isize)
3152 raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
3153
3154 BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
3155 unlock_buffer(bh);
3156 rc = ext3_journal_dirty_metadata(handle, bh);
3157 if (!err)
3158 err = rc;
3159 ext3_clear_inode_state(inode, EXT3_STATE_NEW);
3160
3161 atomic_set(&ei->i_sync_tid, handle->h_transaction->t_tid);
3162 if (need_datasync)
3163 atomic_set(&ei->i_datasync_tid, handle->h_transaction->t_tid);
3164out_brelse:
3165 brelse (bh);
3166 ext3_std_error(inode->i_sb, err);
3167 return err;
3168}
3169
3170/*
3171 * ext3_write_inode()
3172 *
3173 * We are called from a few places:
3174 *
3175 * - Within generic_file_aio_write() -> generic_write_sync() for O_SYNC files.
3176 * Here, there will be no transaction running. We wait for any running
3177 * transaction to commit.
3178 *
3179 * - Within flush work (for sys_sync(), kupdate and such).
3180 * We wait on commit, if told to.
3181 *
3182 * - Within iput_final() -> write_inode_now()
3183 * We wait on commit, if told to.
3184 *
3185 * In all cases it is actually safe for us to return without doing anything,
3186 * because the inode has been copied into a raw inode buffer in
3187 * ext3_mark_inode_dirty(). This is a correctness thing for WB_SYNC_ALL
3188 * writeback.
3189 *
3190 * Note that we are absolutely dependent upon all inode dirtiers doing the
3191 * right thing: they *must* call mark_inode_dirty() after dirtying info in
3192 * which we are interested.
3193 *
3194 * It would be a bug for them to not do this. The code:
3195 *
3196 * mark_inode_dirty(inode)
3197 * stuff();
3198 * inode->i_size = expr;
3199 *
3200 * is in error because write_inode() could occur while `stuff()' is running,
3201 * and the new i_size will be lost. Plus the inode will no longer be on the
3202 * superblock's dirty inode list.
3203 */
3204int ext3_write_inode(struct inode *inode, struct writeback_control *wbc)
3205{
3206 if (WARN_ON_ONCE(current->flags & PF_MEMALLOC))
3207 return 0;
3208
3209 if (ext3_journal_current_handle()) {
3210 jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
3211 dump_stack();
3212 return -EIO;
3213 }
3214
3215 /*
3216 * No need to force transaction in WB_SYNC_NONE mode. Also
3217 * ext3_sync_fs() will force the commit after everything is
3218 * written.
3219 */
3220 if (wbc->sync_mode != WB_SYNC_ALL || wbc->for_sync)
3221 return 0;
3222
3223 return ext3_force_commit(inode->i_sb);
3224}
3225
3226/*
3227 * ext3_setattr()
3228 *
3229 * Called from notify_change.
3230 *
3231 * We want to trap VFS attempts to truncate the file as soon as
3232 * possible. In particular, we want to make sure that when the VFS
3233 * shrinks i_size, we put the inode on the orphan list and modify
3234 * i_disksize immediately, so that during the subsequent flushing of
3235 * dirty pages and freeing of disk blocks, we can guarantee that any
3236 * commit will leave the blocks being flushed in an unused state on
3237 * disk. (On recovery, the inode will get truncated and the blocks will
3238 * be freed, so we have a strong guarantee that no future commit will
3239 * leave these blocks visible to the user.)
3240 *
3241 * Called with inode->sem down.
3242 */
3243int ext3_setattr(struct dentry *dentry, struct iattr *attr)
3244{
3245 struct inode *inode = dentry->d_inode;
3246 int error, rc = 0;
3247 const unsigned int ia_valid = attr->ia_valid;
3248
3249 error = inode_change_ok(inode, attr);
3250 if (error)
3251 return error;
3252
3253 if (is_quota_modification(inode, attr))
3254 dquot_initialize(inode);
3255 if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, inode->i_uid)) ||
3256 (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, inode->i_gid))) {
3257 handle_t *handle;
3258
3259 /* (user+group)*(old+new) structure, inode write (sb,
3260 * inode block, ? - but truncate inode update has it) */
3261 handle = ext3_journal_start(inode, EXT3_MAXQUOTAS_INIT_BLOCKS(inode->i_sb)+
3262 EXT3_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)+3);
3263 if (IS_ERR(handle)) {
3264 error = PTR_ERR(handle);
3265 goto err_out;
3266 }
3267 error = dquot_transfer(inode, attr);
3268 if (error) {
3269 ext3_journal_stop(handle);
3270 return error;
3271 }
3272 /* Update corresponding info in inode so that everything is in
3273 * one transaction */
3274 if (attr->ia_valid & ATTR_UID)
3275 inode->i_uid = attr->ia_uid;
3276 if (attr->ia_valid & ATTR_GID)
3277 inode->i_gid = attr->ia_gid;
3278 error = ext3_mark_inode_dirty(handle, inode);
3279 ext3_journal_stop(handle);
3280 }
3281
3282 if (attr->ia_valid & ATTR_SIZE)
3283 inode_dio_wait(inode);
3284
3285 if (S_ISREG(inode->i_mode) &&
3286 attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
3287 handle_t *handle;
3288
3289 handle = ext3_journal_start(inode, 3);
3290 if (IS_ERR(handle)) {
3291 error = PTR_ERR(handle);
3292 goto err_out;
3293 }
3294
3295 error = ext3_orphan_add(handle, inode);
3296 if (error) {
3297 ext3_journal_stop(handle);
3298 goto err_out;
3299 }
3300 EXT3_I(inode)->i_disksize = attr->ia_size;
3301 error = ext3_mark_inode_dirty(handle, inode);
3302 ext3_journal_stop(handle);
3303 if (error) {
3304 /* Some hard fs error must have happened. Bail out. */
3305 ext3_orphan_del(NULL, inode);
3306 goto err_out;
3307 }
3308 rc = ext3_block_truncate_page(inode, attr->ia_size);
3309 if (rc) {
3310 /* Cleanup orphan list and exit */
3311 handle = ext3_journal_start(inode, 3);
3312 if (IS_ERR(handle)) {
3313 ext3_orphan_del(NULL, inode);
3314 goto err_out;
3315 }
3316 ext3_orphan_del(handle, inode);
3317 ext3_journal_stop(handle);
3318 goto err_out;
3319 }
3320 }
3321
3322 if ((attr->ia_valid & ATTR_SIZE) &&
3323 attr->ia_size != i_size_read(inode)) {
3324 truncate_setsize(inode, attr->ia_size);
3325 ext3_truncate(inode);
3326 }
3327
3328 setattr_copy(inode, attr);
3329 mark_inode_dirty(inode);
3330
3331 if (ia_valid & ATTR_MODE)
3332 rc = posix_acl_chmod(inode, inode->i_mode);
3333
3334err_out:
3335 ext3_std_error(inode->i_sb, error);
3336 if (!error)
3337 error = rc;
3338 return error;
3339}
3340
3341
3342/*
3343 * How many blocks doth make a writepage()?
3344 *
3345 * With N blocks per page, it may be:
3346 * N data blocks
3347 * 2 indirect block
3348 * 2 dindirect
3349 * 1 tindirect
3350 * N+5 bitmap blocks (from the above)
3351 * N+5 group descriptor summary blocks
3352 * 1 inode block
3353 * 1 superblock.
3354 * 2 * EXT3_SINGLEDATA_TRANS_BLOCKS for the quote files
3355 *
3356 * 3 * (N + 5) + 2 + 2 * EXT3_SINGLEDATA_TRANS_BLOCKS
3357 *
3358 * With ordered or writeback data it's the same, less the N data blocks.
3359 *
3360 * If the inode's direct blocks can hold an integral number of pages then a
3361 * page cannot straddle two indirect blocks, and we can only touch one indirect
3362 * and dindirect block, and the "5" above becomes "3".
3363 *
3364 * This still overestimates under most circumstances. If we were to pass the
3365 * start and end offsets in here as well we could do block_to_path() on each
3366 * block and work out the exact number of indirects which are touched. Pah.
3367 */
3368
3369static int ext3_writepage_trans_blocks(struct inode *inode)
3370{
3371 int bpp = ext3_journal_blocks_per_page(inode);
3372 int indirects = (EXT3_NDIR_BLOCKS % bpp) ? 5 : 3;
3373 int ret;
3374
3375 if (ext3_should_journal_data(inode))
3376 ret = 3 * (bpp + indirects) + 2;
3377 else
3378 ret = 2 * (bpp + indirects) + indirects + 2;
3379
3380#ifdef CONFIG_QUOTA
3381 /* We know that structure was already allocated during dquot_initialize so
3382 * we will be updating only the data blocks + inodes */
3383 ret += EXT3_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
3384#endif
3385
3386 return ret;
3387}
3388
3389/*
3390 * The caller must have previously called ext3_reserve_inode_write().
3391 * Give this, we know that the caller already has write access to iloc->bh.
3392 */
3393int ext3_mark_iloc_dirty(handle_t *handle,
3394 struct inode *inode, struct ext3_iloc *iloc)
3395{
3396 int err = 0;
3397
3398 /* the do_update_inode consumes one bh->b_count */
3399 get_bh(iloc->bh);
3400
3401 /* ext3_do_update_inode() does journal_dirty_metadata */
3402 err = ext3_do_update_inode(handle, inode, iloc);
3403 put_bh(iloc->bh);
3404 return err;
3405}
3406
3407/*
3408 * On success, We end up with an outstanding reference count against
3409 * iloc->bh. This _must_ be cleaned up later.
3410 */
3411
3412int
3413ext3_reserve_inode_write(handle_t *handle, struct inode *inode,
3414 struct ext3_iloc *iloc)
3415{
3416 int err = 0;
3417 if (handle) {
3418 err = ext3_get_inode_loc(inode, iloc);
3419 if (!err) {
3420 BUFFER_TRACE(iloc->bh, "get_write_access");
3421 err = ext3_journal_get_write_access(handle, iloc->bh);
3422 if (err) {
3423 brelse(iloc->bh);
3424 iloc->bh = NULL;
3425 }
3426 }
3427 }
3428 ext3_std_error(inode->i_sb, err);
3429 return err;
3430}
3431
3432/*
3433 * What we do here is to mark the in-core inode as clean with respect to inode
3434 * dirtiness (it may still be data-dirty).
3435 * This means that the in-core inode may be reaped by prune_icache
3436 * without having to perform any I/O. This is a very good thing,
3437 * because *any* task may call prune_icache - even ones which
3438 * have a transaction open against a different journal.
3439 *
3440 * Is this cheating? Not really. Sure, we haven't written the
3441 * inode out, but prune_icache isn't a user-visible syncing function.
3442 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
3443 * we start and wait on commits.
3444 */
3445int ext3_mark_inode_dirty(handle_t *handle, struct inode *inode)
3446{
3447 struct ext3_iloc iloc;
3448 int err;
3449
3450 might_sleep();
3451 trace_ext3_mark_inode_dirty(inode, _RET_IP_);
3452 err = ext3_reserve_inode_write(handle, inode, &iloc);
3453 if (!err)
3454 err = ext3_mark_iloc_dirty(handle, inode, &iloc);
3455 return err;
3456}
3457
3458/*
3459 * ext3_dirty_inode() is called from __mark_inode_dirty()
3460 *
3461 * We're really interested in the case where a file is being extended.
3462 * i_size has been changed by generic_commit_write() and we thus need
3463 * to include the updated inode in the current transaction.
3464 *
3465 * Also, dquot_alloc_space() will always dirty the inode when blocks
3466 * are allocated to the file.
3467 *
3468 * If the inode is marked synchronous, we don't honour that here - doing
3469 * so would cause a commit on atime updates, which we don't bother doing.
3470 * We handle synchronous inodes at the highest possible level.
3471 */
3472void ext3_dirty_inode(struct inode *inode, int flags)
3473{
3474 handle_t *current_handle = ext3_journal_current_handle();
3475 handle_t *handle;
3476
3477 handle = ext3_journal_start(inode, 2);
3478 if (IS_ERR(handle))
3479 goto out;
3480 if (current_handle &&
3481 current_handle->h_transaction != handle->h_transaction) {
3482 /* This task has a transaction open against a different fs */
3483 printk(KERN_EMERG "%s: transactions do not match!\n",
3484 __func__);
3485 } else {
3486 jbd_debug(5, "marking dirty. outer handle=%p\n",
3487 current_handle);
3488 ext3_mark_inode_dirty(handle, inode);
3489 }
3490 ext3_journal_stop(handle);
3491out:
3492 return;
3493}
3494
3495#if 0
3496/*
3497 * Bind an inode's backing buffer_head into this transaction, to prevent
3498 * it from being flushed to disk early. Unlike
3499 * ext3_reserve_inode_write, this leaves behind no bh reference and
3500 * returns no iloc structure, so the caller needs to repeat the iloc
3501 * lookup to mark the inode dirty later.
3502 */
3503static int ext3_pin_inode(handle_t *handle, struct inode *inode)
3504{
3505 struct ext3_iloc iloc;
3506
3507 int err = 0;
3508 if (handle) {
3509 err = ext3_get_inode_loc(inode, &iloc);
3510 if (!err) {
3511 BUFFER_TRACE(iloc.bh, "get_write_access");
3512 err = journal_get_write_access(handle, iloc.bh);
3513 if (!err)
3514 err = ext3_journal_dirty_metadata(handle,
3515 iloc.bh);
3516 brelse(iloc.bh);
3517 }
3518 }
3519 ext3_std_error(inode->i_sb, err);
3520 return err;
3521}
3522#endif
3523
3524int ext3_change_inode_journal_flag(struct inode *inode, int val)
3525{
3526 journal_t *journal;
3527 handle_t *handle;
3528 int err;
3529
3530 /*
3531 * We have to be very careful here: changing a data block's
3532 * journaling status dynamically is dangerous. If we write a
3533 * data block to the journal, change the status and then delete
3534 * that block, we risk forgetting to revoke the old log record
3535 * from the journal and so a subsequent replay can corrupt data.
3536 * So, first we make sure that the journal is empty and that
3537 * nobody is changing anything.
3538 */
3539
3540 journal = EXT3_JOURNAL(inode);
3541 if (is_journal_aborted(journal))
3542 return -EROFS;
3543
3544 journal_lock_updates(journal);
3545 journal_flush(journal);
3546
3547 /*
3548 * OK, there are no updates running now, and all cached data is
3549 * synced to disk. We are now in a completely consistent state
3550 * which doesn't have anything in the journal, and we know that
3551 * no filesystem updates are running, so it is safe to modify
3552 * the inode's in-core data-journaling state flag now.
3553 */
3554
3555 if (val)
3556 EXT3_I(inode)->i_flags |= EXT3_JOURNAL_DATA_FL;
3557 else
3558 EXT3_I(inode)->i_flags &= ~EXT3_JOURNAL_DATA_FL;
3559 ext3_set_aops(inode);
3560
3561 journal_unlock_updates(journal);
3562
3563 /* Finally we can mark the inode as dirty. */
3564
3565 handle = ext3_journal_start(inode, 1);
3566 if (IS_ERR(handle))
3567 return PTR_ERR(handle);
3568
3569 err = ext3_mark_inode_dirty(handle, inode);
3570 handle->h_sync = 1;
3571 ext3_journal_stop(handle);
3572 ext3_std_error(inode->i_sb, err);
3573
3574 return err;
3575}