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-rw-r--r--fs/ext3/inode.c3574
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diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
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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/uio.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 trace_ext3_journalled_writepage(page);
1720 if (!page_has_buffers(page) || PageChecked(page)) {
1721 if (ext3_journal_current_handle())
1722 goto no_write;
1723
1724 handle = ext3_journal_start(inode,
1725 ext3_writepage_trans_blocks(inode));
1726 if (IS_ERR(handle)) {
1727 ret = PTR_ERR(handle);
1728 goto no_write;
1729 }
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 err = ext3_journal_stop(handle);
1753 if (!ret)
1754 ret = err;
1755 } else {
1756 /*
1757 * It is a page full of checkpoint-mode buffers. Go and write
1758 * them. They should have been already mapped when they went
1759 * to the journal so provide NULL get_block function to catch
1760 * errors.
1761 */
1762 ret = block_write_full_page(page, NULL, wbc);
1763 }
1764out:
1765 return ret;
1766
1767no_write:
1768 redirty_page_for_writepage(wbc, page);
1769out_unlock:
1770 unlock_page(page);
1771 goto out;
1772}
1773
1774static int ext3_readpage(struct file *file, struct page *page)
1775{
1776 trace_ext3_readpage(page);
1777 return mpage_readpage(page, ext3_get_block);
1778}
1779
1780static int
1781ext3_readpages(struct file *file, struct address_space *mapping,
1782 struct list_head *pages, unsigned nr_pages)
1783{
1784 return mpage_readpages(mapping, pages, nr_pages, ext3_get_block);
1785}
1786
1787static void ext3_invalidatepage(struct page *page, unsigned int offset,
1788 unsigned int length)
1789{
1790 journal_t *journal = EXT3_JOURNAL(page->mapping->host);
1791
1792 trace_ext3_invalidatepage(page, offset, length);
1793
1794 /*
1795 * If it's a full truncate we just forget about the pending dirtying
1796 */
1797 if (offset == 0 && length == PAGE_CACHE_SIZE)
1798 ClearPageChecked(page);
1799
1800 journal_invalidatepage(journal, page, offset, length);
1801}
1802
1803static int ext3_releasepage(struct page *page, gfp_t wait)
1804{
1805 journal_t *journal = EXT3_JOURNAL(page->mapping->host);
1806
1807 trace_ext3_releasepage(page);
1808 WARN_ON(PageChecked(page));
1809 if (!page_has_buffers(page))
1810 return 0;
1811 return journal_try_to_free_buffers(journal, page, wait);
1812}
1813
1814/*
1815 * If the O_DIRECT write will extend the file then add this inode to the
1816 * orphan list. So recovery will truncate it back to the original size
1817 * if the machine crashes during the write.
1818 *
1819 * If the O_DIRECT write is intantiating holes inside i_size and the machine
1820 * crashes then stale disk data _may_ be exposed inside the file. But current
1821 * VFS code falls back into buffered path in that case so we are safe.
1822 */
1823static ssize_t ext3_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
1824 loff_t offset)
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_iter_count(iter);
1833 int retries = 0;
1834
1835 trace_ext3_direct_IO_enter(inode, offset, count, iov_iter_rw(iter));
1836
1837 if (iov_iter_rw(iter) == 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(iocb, inode, iter, offset, ext3_get_block);
1860 /*
1861 * In case of error extending write may have instantiated a few
1862 * blocks outside i_size. Trim these off again.
1863 */
1864 if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
1865 loff_t isize = i_size_read(inode);
1866 loff_t end = offset + count;
1867
1868 if (end > isize)
1869 ext3_truncate_failed_direct_write(inode);
1870 }
1871 if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
1872 goto retry;
1873
1874 if (orphan) {
1875 int err;
1876
1877 /* Credits for sb + inode write */
1878 handle = ext3_journal_start(inode, 2);
1879 if (IS_ERR(handle)) {
1880 /* This is really bad luck. We've written the data
1881 * but cannot extend i_size. Truncate allocated blocks
1882 * and pretend the write failed... */
1883 ext3_truncate_failed_direct_write(inode);
1884 ret = PTR_ERR(handle);
1885 if (inode->i_nlink)
1886 ext3_orphan_del(NULL, inode);
1887 goto out;
1888 }
1889 if (inode->i_nlink)
1890 ext3_orphan_del(handle, inode);
1891 if (ret > 0) {
1892 loff_t end = offset + ret;
1893 if (end > inode->i_size) {
1894 ei->i_disksize = end;
1895 i_size_write(inode, end);
1896 /*
1897 * We're going to return a positive `ret'
1898 * here due to non-zero-length I/O, so there's
1899 * no way of reporting error returns from
1900 * ext3_mark_inode_dirty() to userspace. So
1901 * ignore it.
1902 */
1903 ext3_mark_inode_dirty(handle, inode);
1904 }
1905 }
1906 err = ext3_journal_stop(handle);
1907 if (ret == 0)
1908 ret = err;
1909 }
1910out:
1911 trace_ext3_direct_IO_exit(inode, offset, count, iov_iter_rw(iter), ret);
1912 return ret;
1913}
1914
1915/*
1916 * Pages can be marked dirty completely asynchronously from ext3's journalling
1917 * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do
1918 * much here because ->set_page_dirty is called under VFS locks. The page is
1919 * not necessarily locked.
1920 *
1921 * We cannot just dirty the page and leave attached buffers clean, because the
1922 * buffers' dirty state is "definitive". We cannot just set the buffers dirty
1923 * or jbddirty because all the journalling code will explode.
1924 *
1925 * So what we do is to mark the page "pending dirty" and next time writepage
1926 * is called, propagate that into the buffers appropriately.
1927 */
1928static int ext3_journalled_set_page_dirty(struct page *page)
1929{
1930 SetPageChecked(page);
1931 return __set_page_dirty_nobuffers(page);
1932}
1933
1934static const struct address_space_operations ext3_ordered_aops = {
1935 .readpage = ext3_readpage,
1936 .readpages = ext3_readpages,
1937 .writepage = ext3_ordered_writepage,
1938 .write_begin = ext3_write_begin,
1939 .write_end = ext3_ordered_write_end,
1940 .bmap = ext3_bmap,
1941 .invalidatepage = ext3_invalidatepage,
1942 .releasepage = ext3_releasepage,
1943 .direct_IO = ext3_direct_IO,
1944 .migratepage = buffer_migrate_page,
1945 .is_partially_uptodate = block_is_partially_uptodate,
1946 .is_dirty_writeback = buffer_check_dirty_writeback,
1947 .error_remove_page = generic_error_remove_page,
1948};
1949
1950static const struct address_space_operations ext3_writeback_aops = {
1951 .readpage = ext3_readpage,
1952 .readpages = ext3_readpages,
1953 .writepage = ext3_writeback_writepage,
1954 .write_begin = ext3_write_begin,
1955 .write_end = ext3_writeback_write_end,
1956 .bmap = ext3_bmap,
1957 .invalidatepage = ext3_invalidatepage,
1958 .releasepage = ext3_releasepage,
1959 .direct_IO = ext3_direct_IO,
1960 .migratepage = buffer_migrate_page,
1961 .is_partially_uptodate = block_is_partially_uptodate,
1962 .error_remove_page = generic_error_remove_page,
1963};
1964
1965static const struct address_space_operations ext3_journalled_aops = {
1966 .readpage = ext3_readpage,
1967 .readpages = ext3_readpages,
1968 .writepage = ext3_journalled_writepage,
1969 .write_begin = ext3_write_begin,
1970 .write_end = ext3_journalled_write_end,
1971 .set_page_dirty = ext3_journalled_set_page_dirty,
1972 .bmap = ext3_bmap,
1973 .invalidatepage = ext3_invalidatepage,
1974 .releasepage = ext3_releasepage,
1975 .is_partially_uptodate = block_is_partially_uptodate,
1976 .error_remove_page = generic_error_remove_page,
1977};
1978
1979void ext3_set_aops(struct inode *inode)
1980{
1981 if (ext3_should_order_data(inode))
1982 inode->i_mapping->a_ops = &ext3_ordered_aops;
1983 else if (ext3_should_writeback_data(inode))
1984 inode->i_mapping->a_ops = &ext3_writeback_aops;
1985 else
1986 inode->i_mapping->a_ops = &ext3_journalled_aops;
1987}
1988
1989/*
1990 * ext3_block_truncate_page() zeroes out a mapping from file offset `from'
1991 * up to the end of the block which corresponds to `from'.
1992 * This required during truncate. We need to physically zero the tail end
1993 * of that block so it doesn't yield old data if the file is later grown.
1994 */
1995static int ext3_block_truncate_page(struct inode *inode, loff_t from)
1996{
1997 ext3_fsblk_t index = from >> PAGE_CACHE_SHIFT;
1998 unsigned offset = from & (PAGE_CACHE_SIZE - 1);
1999 unsigned blocksize, iblock, length, pos;
2000 struct page *page;
2001 handle_t *handle = NULL;
2002 struct buffer_head *bh;
2003 int err = 0;
2004
2005 /* Truncated on block boundary - nothing to do */
2006 blocksize = inode->i_sb->s_blocksize;
2007 if ((from & (blocksize - 1)) == 0)
2008 return 0;
2009
2010 page = grab_cache_page(inode->i_mapping, index);
2011 if (!page)
2012 return -ENOMEM;
2013 length = blocksize - (offset & (blocksize - 1));
2014 iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
2015
2016 if (!page_has_buffers(page))
2017 create_empty_buffers(page, blocksize, 0);
2018
2019 /* Find the buffer that contains "offset" */
2020 bh = page_buffers(page);
2021 pos = blocksize;
2022 while (offset >= pos) {
2023 bh = bh->b_this_page;
2024 iblock++;
2025 pos += blocksize;
2026 }
2027
2028 err = 0;
2029 if (buffer_freed(bh)) {
2030 BUFFER_TRACE(bh, "freed: skip");
2031 goto unlock;
2032 }
2033
2034 if (!buffer_mapped(bh)) {
2035 BUFFER_TRACE(bh, "unmapped");
2036 ext3_get_block(inode, iblock, bh, 0);
2037 /* unmapped? It's a hole - nothing to do */
2038 if (!buffer_mapped(bh)) {
2039 BUFFER_TRACE(bh, "still unmapped");
2040 goto unlock;
2041 }
2042 }
2043
2044 /* Ok, it's mapped. Make sure it's up-to-date */
2045 if (PageUptodate(page))
2046 set_buffer_uptodate(bh);
2047
2048 if (!bh_uptodate_or_lock(bh)) {
2049 err = bh_submit_read(bh);
2050 /* Uhhuh. Read error. Complain and punt. */
2051 if (err)
2052 goto unlock;
2053 }
2054
2055 /* data=writeback mode doesn't need transaction to zero-out data */
2056 if (!ext3_should_writeback_data(inode)) {
2057 /* We journal at most one block */
2058 handle = ext3_journal_start(inode, 1);
2059 if (IS_ERR(handle)) {
2060 clear_highpage(page);
2061 flush_dcache_page(page);
2062 err = PTR_ERR(handle);
2063 goto unlock;
2064 }
2065 }
2066
2067 if (ext3_should_journal_data(inode)) {
2068 BUFFER_TRACE(bh, "get write access");
2069 err = ext3_journal_get_write_access(handle, bh);
2070 if (err)
2071 goto stop;
2072 }
2073
2074 zero_user(page, offset, length);
2075 BUFFER_TRACE(bh, "zeroed end of block");
2076
2077 err = 0;
2078 if (ext3_should_journal_data(inode)) {
2079 err = ext3_journal_dirty_metadata(handle, bh);
2080 } else {
2081 if (ext3_should_order_data(inode))
2082 err = ext3_journal_dirty_data(handle, bh);
2083 mark_buffer_dirty(bh);
2084 }
2085stop:
2086 if (handle)
2087 ext3_journal_stop(handle);
2088
2089unlock:
2090 unlock_page(page);
2091 page_cache_release(page);
2092 return err;
2093}
2094
2095/*
2096 * Probably it should be a library function... search for first non-zero word
2097 * or memcmp with zero_page, whatever is better for particular architecture.
2098 * Linus?
2099 */
2100static inline int all_zeroes(__le32 *p, __le32 *q)
2101{
2102 while (p < q)
2103 if (*p++)
2104 return 0;
2105 return 1;
2106}
2107
2108/**
2109 * ext3_find_shared - find the indirect blocks for partial truncation.
2110 * @inode: inode in question
2111 * @depth: depth of the affected branch
2112 * @offsets: offsets of pointers in that branch (see ext3_block_to_path)
2113 * @chain: place to store the pointers to partial indirect blocks
2114 * @top: place to the (detached) top of branch
2115 *
2116 * This is a helper function used by ext3_truncate().
2117 *
2118 * When we do truncate() we may have to clean the ends of several
2119 * indirect blocks but leave the blocks themselves alive. Block is
2120 * partially truncated if some data below the new i_size is referred
2121 * from it (and it is on the path to the first completely truncated
2122 * data block, indeed). We have to free the top of that path along
2123 * with everything to the right of the path. Since no allocation
2124 * past the truncation point is possible until ext3_truncate()
2125 * finishes, we may safely do the latter, but top of branch may
2126 * require special attention - pageout below the truncation point
2127 * might try to populate it.
2128 *
2129 * We atomically detach the top of branch from the tree, store the
2130 * block number of its root in *@top, pointers to buffer_heads of
2131 * partially truncated blocks - in @chain[].bh and pointers to
2132 * their last elements that should not be removed - in
2133 * @chain[].p. Return value is the pointer to last filled element
2134 * of @chain.
2135 *
2136 * The work left to caller to do the actual freeing of subtrees:
2137 * a) free the subtree starting from *@top
2138 * b) free the subtrees whose roots are stored in
2139 * (@chain[i].p+1 .. end of @chain[i].bh->b_data)
2140 * c) free the subtrees growing from the inode past the @chain[0].
2141 * (no partially truncated stuff there). */
2142
2143static Indirect *ext3_find_shared(struct inode *inode, int depth,
2144 int offsets[4], Indirect chain[4], __le32 *top)
2145{
2146 Indirect *partial, *p;
2147 int k, err;
2148
2149 *top = 0;
2150 /* Make k index the deepest non-null offset + 1 */
2151 for (k = depth; k > 1 && !offsets[k-1]; k--)
2152 ;
2153 partial = ext3_get_branch(inode, k, offsets, chain, &err);
2154 /* Writer: pointers */
2155 if (!partial)
2156 partial = chain + k-1;
2157 /*
2158 * If the branch acquired continuation since we've looked at it -
2159 * fine, it should all survive and (new) top doesn't belong to us.
2160 */
2161 if (!partial->key && *partial->p)
2162 /* Writer: end */
2163 goto no_top;
2164 for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
2165 ;
2166 /*
2167 * OK, we've found the last block that must survive. The rest of our
2168 * branch should be detached before unlocking. However, if that rest
2169 * of branch is all ours and does not grow immediately from the inode
2170 * it's easier to cheat and just decrement partial->p.
2171 */
2172 if (p == chain + k - 1 && p > chain) {
2173 p->p--;
2174 } else {
2175 *top = *p->p;
2176 /* Nope, don't do this in ext3. Must leave the tree intact */
2177#if 0
2178 *p->p = 0;
2179#endif
2180 }
2181 /* Writer: end */
2182
2183 while(partial > p) {
2184 brelse(partial->bh);
2185 partial--;
2186 }
2187no_top:
2188 return partial;
2189}
2190
2191/*
2192 * Zero a number of block pointers in either an inode or an indirect block.
2193 * If we restart the transaction we must again get write access to the
2194 * indirect block for further modification.
2195 *
2196 * We release `count' blocks on disk, but (last - first) may be greater
2197 * than `count' because there can be holes in there.
2198 */
2199static void ext3_clear_blocks(handle_t *handle, struct inode *inode,
2200 struct buffer_head *bh, ext3_fsblk_t block_to_free,
2201 unsigned long count, __le32 *first, __le32 *last)
2202{
2203 __le32 *p;
2204 if (try_to_extend_transaction(handle, inode)) {
2205 if (bh) {
2206 BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
2207 if (ext3_journal_dirty_metadata(handle, bh))
2208 return;
2209 }
2210 ext3_mark_inode_dirty(handle, inode);
2211 truncate_restart_transaction(handle, inode);
2212 if (bh) {
2213 BUFFER_TRACE(bh, "retaking write access");
2214 if (ext3_journal_get_write_access(handle, bh))
2215 return;
2216 }
2217 }
2218
2219 /*
2220 * Any buffers which are on the journal will be in memory. We find
2221 * them on the hash table so journal_revoke() will run journal_forget()
2222 * on them. We've already detached each block from the file, so
2223 * bforget() in journal_forget() should be safe.
2224 *
2225 * AKPM: turn on bforget in journal_forget()!!!
2226 */
2227 for (p = first; p < last; p++) {
2228 u32 nr = le32_to_cpu(*p);
2229 if (nr) {
2230 struct buffer_head *bh;
2231
2232 *p = 0;
2233 bh = sb_find_get_block(inode->i_sb, nr);
2234 ext3_forget(handle, 0, inode, bh, nr);
2235 }
2236 }
2237
2238 ext3_free_blocks(handle, inode, block_to_free, count);
2239}
2240
2241/**
2242 * ext3_free_data - free a list of data blocks
2243 * @handle: handle for this transaction
2244 * @inode: inode we are dealing with
2245 * @this_bh: indirect buffer_head which contains *@first and *@last
2246 * @first: array of block numbers
2247 * @last: points immediately past the end of array
2248 *
2249 * We are freeing all blocks referred from that array (numbers are stored as
2250 * little-endian 32-bit) and updating @inode->i_blocks appropriately.
2251 *
2252 * We accumulate contiguous runs of blocks to free. Conveniently, if these
2253 * blocks are contiguous then releasing them at one time will only affect one
2254 * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
2255 * actually use a lot of journal space.
2256 *
2257 * @this_bh will be %NULL if @first and @last point into the inode's direct
2258 * block pointers.
2259 */
2260static void ext3_free_data(handle_t *handle, struct inode *inode,
2261 struct buffer_head *this_bh,
2262 __le32 *first, __le32 *last)
2263{
2264 ext3_fsblk_t block_to_free = 0; /* Starting block # of a run */
2265 unsigned long count = 0; /* Number of blocks in the run */
2266 __le32 *block_to_free_p = NULL; /* Pointer into inode/ind
2267 corresponding to
2268 block_to_free */
2269 ext3_fsblk_t nr; /* Current block # */
2270 __le32 *p; /* Pointer into inode/ind
2271 for current block */
2272 int err;
2273
2274 if (this_bh) { /* For indirect block */
2275 BUFFER_TRACE(this_bh, "get_write_access");
2276 err = ext3_journal_get_write_access(handle, this_bh);
2277 /* Important: if we can't update the indirect pointers
2278 * to the blocks, we can't free them. */
2279 if (err)
2280 return;
2281 }
2282
2283 for (p = first; p < last; p++) {
2284 nr = le32_to_cpu(*p);
2285 if (nr) {
2286 /* accumulate blocks to free if they're contiguous */
2287 if (count == 0) {
2288 block_to_free = nr;
2289 block_to_free_p = p;
2290 count = 1;
2291 } else if (nr == block_to_free + count) {
2292 count++;
2293 } else {
2294 ext3_clear_blocks(handle, inode, this_bh,
2295 block_to_free,
2296 count, block_to_free_p, p);
2297 block_to_free = nr;
2298 block_to_free_p = p;
2299 count = 1;
2300 }
2301 }
2302 }
2303
2304 if (count > 0)
2305 ext3_clear_blocks(handle, inode, this_bh, block_to_free,
2306 count, block_to_free_p, p);
2307
2308 if (this_bh) {
2309 BUFFER_TRACE(this_bh, "call ext3_journal_dirty_metadata");
2310
2311 /*
2312 * The buffer head should have an attached journal head at this
2313 * point. However, if the data is corrupted and an indirect
2314 * block pointed to itself, it would have been detached when
2315 * the block was cleared. Check for this instead of OOPSing.
2316 */
2317 if (bh2jh(this_bh))
2318 ext3_journal_dirty_metadata(handle, this_bh);
2319 else
2320 ext3_error(inode->i_sb, "ext3_free_data",
2321 "circular indirect block detected, "
2322 "inode=%lu, block=%llu",
2323 inode->i_ino,
2324 (unsigned long long)this_bh->b_blocknr);
2325 }
2326}
2327
2328/**
2329 * ext3_free_branches - free an array of branches
2330 * @handle: JBD handle for this transaction
2331 * @inode: inode we are dealing with
2332 * @parent_bh: the buffer_head which contains *@first and *@last
2333 * @first: array of block numbers
2334 * @last: pointer immediately past the end of array
2335 * @depth: depth of the branches to free
2336 *
2337 * We are freeing all blocks referred from these branches (numbers are
2338 * stored as little-endian 32-bit) and updating @inode->i_blocks
2339 * appropriately.
2340 */
2341static void ext3_free_branches(handle_t *handle, struct inode *inode,
2342 struct buffer_head *parent_bh,
2343 __le32 *first, __le32 *last, int depth)
2344{
2345 ext3_fsblk_t nr;
2346 __le32 *p;
2347
2348 if (is_handle_aborted(handle))
2349 return;
2350
2351 if (depth--) {
2352 struct buffer_head *bh;
2353 int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
2354 p = last;
2355 while (--p >= first) {
2356 nr = le32_to_cpu(*p);
2357 if (!nr)
2358 continue; /* A hole */
2359
2360 /* Go read the buffer for the next level down */
2361 bh = sb_bread(inode->i_sb, nr);
2362
2363 /*
2364 * A read failure? Report error and clear slot
2365 * (should be rare).
2366 */
2367 if (!bh) {
2368 ext3_error(inode->i_sb, "ext3_free_branches",
2369 "Read failure, inode=%lu, block="E3FSBLK,
2370 inode->i_ino, nr);
2371 continue;
2372 }
2373
2374 /* This zaps the entire block. Bottom up. */
2375 BUFFER_TRACE(bh, "free child branches");
2376 ext3_free_branches(handle, inode, bh,
2377 (__le32*)bh->b_data,
2378 (__le32*)bh->b_data + addr_per_block,
2379 depth);
2380
2381 /*
2382 * Everything below this this pointer has been
2383 * released. Now let this top-of-subtree go.
2384 *
2385 * We want the freeing of this indirect block to be
2386 * atomic in the journal with the updating of the
2387 * bitmap block which owns it. So make some room in
2388 * the journal.
2389 *
2390 * We zero the parent pointer *after* freeing its
2391 * pointee in the bitmaps, so if extend_transaction()
2392 * for some reason fails to put the bitmap changes and
2393 * the release into the same transaction, recovery
2394 * will merely complain about releasing a free block,
2395 * rather than leaking blocks.
2396 */
2397 if (is_handle_aborted(handle))
2398 return;
2399 if (try_to_extend_transaction(handle, inode)) {
2400 ext3_mark_inode_dirty(handle, inode);
2401 truncate_restart_transaction(handle, inode);
2402 }
2403
2404 /*
2405 * We've probably journalled the indirect block several
2406 * times during the truncate. But it's no longer
2407 * needed and we now drop it from the transaction via
2408 * journal_revoke().
2409 *
2410 * That's easy if it's exclusively part of this
2411 * transaction. But if it's part of the committing
2412 * transaction then journal_forget() will simply
2413 * brelse() it. That means that if the underlying
2414 * block is reallocated in ext3_get_block(),
2415 * unmap_underlying_metadata() will find this block
2416 * and will try to get rid of it. damn, damn. Thus
2417 * we don't allow a block to be reallocated until
2418 * a transaction freeing it has fully committed.
2419 *
2420 * We also have to make sure journal replay after a
2421 * crash does not overwrite non-journaled data blocks
2422 * with old metadata when the block got reallocated for
2423 * data. Thus we have to store a revoke record for a
2424 * block in the same transaction in which we free the
2425 * block.
2426 */
2427 ext3_forget(handle, 1, inode, bh, bh->b_blocknr);
2428
2429 ext3_free_blocks(handle, inode, nr, 1);
2430
2431 if (parent_bh) {
2432 /*
2433 * The block which we have just freed is
2434 * pointed to by an indirect block: journal it
2435 */
2436 BUFFER_TRACE(parent_bh, "get_write_access");
2437 if (!ext3_journal_get_write_access(handle,
2438 parent_bh)){
2439 *p = 0;
2440 BUFFER_TRACE(parent_bh,
2441 "call ext3_journal_dirty_metadata");
2442 ext3_journal_dirty_metadata(handle,
2443 parent_bh);
2444 }
2445 }
2446 }
2447 } else {
2448 /* We have reached the bottom of the tree. */
2449 BUFFER_TRACE(parent_bh, "free data blocks");
2450 ext3_free_data(handle, inode, parent_bh, first, last);
2451 }
2452}
2453
2454int ext3_can_truncate(struct inode *inode)
2455{
2456 if (S_ISREG(inode->i_mode))
2457 return 1;
2458 if (S_ISDIR(inode->i_mode))
2459 return 1;
2460 if (S_ISLNK(inode->i_mode))
2461 return !ext3_inode_is_fast_symlink(inode);
2462 return 0;
2463}
2464
2465/*
2466 * ext3_truncate()
2467 *
2468 * We block out ext3_get_block() block instantiations across the entire
2469 * transaction, and VFS/VM ensures that ext3_truncate() cannot run
2470 * simultaneously on behalf of the same inode.
2471 *
2472 * As we work through the truncate and commit bits of it to the journal there
2473 * is one core, guiding principle: the file's tree must always be consistent on
2474 * disk. We must be able to restart the truncate after a crash.
2475 *
2476 * The file's tree may be transiently inconsistent in memory (although it
2477 * probably isn't), but whenever we close off and commit a journal transaction,
2478 * the contents of (the filesystem + the journal) must be consistent and
2479 * restartable. It's pretty simple, really: bottom up, right to left (although
2480 * left-to-right works OK too).
2481 *
2482 * Note that at recovery time, journal replay occurs *before* the restart of
2483 * truncate against the orphan inode list.
2484 *
2485 * The committed inode has the new, desired i_size (which is the same as
2486 * i_disksize in this case). After a crash, ext3_orphan_cleanup() will see
2487 * that this inode's truncate did not complete and it will again call
2488 * ext3_truncate() to have another go. So there will be instantiated blocks
2489 * to the right of the truncation point in a crashed ext3 filesystem. But
2490 * that's fine - as long as they are linked from the inode, the post-crash
2491 * ext3_truncate() run will find them and release them.
2492 */
2493void ext3_truncate(struct inode *inode)
2494{
2495 handle_t *handle;
2496 struct ext3_inode_info *ei = EXT3_I(inode);
2497 __le32 *i_data = ei->i_data;
2498 int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
2499 int offsets[4];
2500 Indirect chain[4];
2501 Indirect *partial;
2502 __le32 nr = 0;
2503 int n;
2504 long last_block;
2505 unsigned blocksize = inode->i_sb->s_blocksize;
2506
2507 trace_ext3_truncate_enter(inode);
2508
2509 if (!ext3_can_truncate(inode))
2510 goto out_notrans;
2511
2512 if (inode->i_size == 0 && ext3_should_writeback_data(inode))
2513 ext3_set_inode_state(inode, EXT3_STATE_FLUSH_ON_CLOSE);
2514
2515 handle = start_transaction(inode);
2516 if (IS_ERR(handle))
2517 goto out_notrans;
2518
2519 last_block = (inode->i_size + blocksize-1)
2520 >> EXT3_BLOCK_SIZE_BITS(inode->i_sb);
2521 n = ext3_block_to_path(inode, last_block, offsets, NULL);
2522 if (n == 0)
2523 goto out_stop; /* error */
2524
2525 /*
2526 * OK. This truncate is going to happen. We add the inode to the
2527 * orphan list, so that if this truncate spans multiple transactions,
2528 * and we crash, we will resume the truncate when the filesystem
2529 * recovers. It also marks the inode dirty, to catch the new size.
2530 *
2531 * Implication: the file must always be in a sane, consistent
2532 * truncatable state while each transaction commits.
2533 */
2534 if (ext3_orphan_add(handle, inode))
2535 goto out_stop;
2536
2537 /*
2538 * The orphan list entry will now protect us from any crash which
2539 * occurs before the truncate completes, so it is now safe to propagate
2540 * the new, shorter inode size (held for now in i_size) into the
2541 * on-disk inode. We do this via i_disksize, which is the value which
2542 * ext3 *really* writes onto the disk inode.
2543 */
2544 ei->i_disksize = inode->i_size;
2545
2546 /*
2547 * From here we block out all ext3_get_block() callers who want to
2548 * modify the block allocation tree.
2549 */
2550 mutex_lock(&ei->truncate_mutex);
2551
2552 if (n == 1) { /* direct blocks */
2553 ext3_free_data(handle, inode, NULL, i_data+offsets[0],
2554 i_data + EXT3_NDIR_BLOCKS);
2555 goto do_indirects;
2556 }
2557
2558 partial = ext3_find_shared(inode, n, offsets, chain, &nr);
2559 /* Kill the top of shared branch (not detached) */
2560 if (nr) {
2561 if (partial == chain) {
2562 /* Shared branch grows from the inode */
2563 ext3_free_branches(handle, inode, NULL,
2564 &nr, &nr+1, (chain+n-1) - partial);
2565 *partial->p = 0;
2566 /*
2567 * We mark the inode dirty prior to restart,
2568 * and prior to stop. No need for it here.
2569 */
2570 } else {
2571 /* Shared branch grows from an indirect block */
2572 ext3_free_branches(handle, inode, partial->bh,
2573 partial->p,
2574 partial->p+1, (chain+n-1) - partial);
2575 }
2576 }
2577 /* Clear the ends of indirect blocks on the shared branch */
2578 while (partial > chain) {
2579 ext3_free_branches(handle, inode, partial->bh, partial->p + 1,
2580 (__le32*)partial->bh->b_data+addr_per_block,
2581 (chain+n-1) - partial);
2582 BUFFER_TRACE(partial->bh, "call brelse");
2583 brelse (partial->bh);
2584 partial--;
2585 }
2586do_indirects:
2587 /* Kill the remaining (whole) subtrees */
2588 switch (offsets[0]) {
2589 default:
2590 nr = i_data[EXT3_IND_BLOCK];
2591 if (nr) {
2592 ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
2593 i_data[EXT3_IND_BLOCK] = 0;
2594 }
2595 case EXT3_IND_BLOCK:
2596 nr = i_data[EXT3_DIND_BLOCK];
2597 if (nr) {
2598 ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
2599 i_data[EXT3_DIND_BLOCK] = 0;
2600 }
2601 case EXT3_DIND_BLOCK:
2602 nr = i_data[EXT3_TIND_BLOCK];
2603 if (nr) {
2604 ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
2605 i_data[EXT3_TIND_BLOCK] = 0;
2606 }
2607 case EXT3_TIND_BLOCK:
2608 ;
2609 }
2610
2611 ext3_discard_reservation(inode);
2612
2613 mutex_unlock(&ei->truncate_mutex);
2614 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
2615 ext3_mark_inode_dirty(handle, inode);
2616
2617 /*
2618 * In a multi-transaction truncate, we only make the final transaction
2619 * synchronous
2620 */
2621 if (IS_SYNC(inode))
2622 handle->h_sync = 1;
2623out_stop:
2624 /*
2625 * If this was a simple ftruncate(), and the file will remain alive
2626 * then we need to clear up the orphan record which we created above.
2627 * However, if this was a real unlink then we were called by
2628 * ext3_evict_inode(), and we allow that function to clean up the
2629 * orphan info for us.
2630 */
2631 if (inode->i_nlink)
2632 ext3_orphan_del(handle, inode);
2633
2634 ext3_journal_stop(handle);
2635 trace_ext3_truncate_exit(inode);
2636 return;
2637out_notrans:
2638 /*
2639 * Delete the inode from orphan list so that it doesn't stay there
2640 * forever and trigger assertion on umount.
2641 */
2642 if (inode->i_nlink)
2643 ext3_orphan_del(NULL, inode);
2644 trace_ext3_truncate_exit(inode);
2645}
2646
2647static ext3_fsblk_t ext3_get_inode_block(struct super_block *sb,
2648 unsigned long ino, struct ext3_iloc *iloc)
2649{
2650 unsigned long block_group;
2651 unsigned long offset;
2652 ext3_fsblk_t block;
2653 struct ext3_group_desc *gdp;
2654
2655 if (!ext3_valid_inum(sb, ino)) {
2656 /*
2657 * This error is already checked for in namei.c unless we are
2658 * looking at an NFS filehandle, in which case no error
2659 * report is needed
2660 */
2661 return 0;
2662 }
2663
2664 block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
2665 gdp = ext3_get_group_desc(sb, block_group, NULL);
2666 if (!gdp)
2667 return 0;
2668 /*
2669 * Figure out the offset within the block group inode table
2670 */
2671 offset = ((ino - 1) % EXT3_INODES_PER_GROUP(sb)) *
2672 EXT3_INODE_SIZE(sb);
2673 block = le32_to_cpu(gdp->bg_inode_table) +
2674 (offset >> EXT3_BLOCK_SIZE_BITS(sb));
2675
2676 iloc->block_group = block_group;
2677 iloc->offset = offset & (EXT3_BLOCK_SIZE(sb) - 1);
2678 return block;
2679}
2680
2681/*
2682 * ext3_get_inode_loc returns with an extra refcount against the inode's
2683 * underlying buffer_head on success. If 'in_mem' is true, we have all
2684 * data in memory that is needed to recreate the on-disk version of this
2685 * inode.
2686 */
2687static int __ext3_get_inode_loc(struct inode *inode,
2688 struct ext3_iloc *iloc, int in_mem)
2689{
2690 ext3_fsblk_t block;
2691 struct buffer_head *bh;
2692
2693 block = ext3_get_inode_block(inode->i_sb, inode->i_ino, iloc);
2694 if (!block)
2695 return -EIO;
2696
2697 bh = sb_getblk(inode->i_sb, block);
2698 if (unlikely(!bh)) {
2699 ext3_error (inode->i_sb, "ext3_get_inode_loc",
2700 "unable to read inode block - "
2701 "inode=%lu, block="E3FSBLK,
2702 inode->i_ino, block);
2703 return -ENOMEM;
2704 }
2705 if (!buffer_uptodate(bh)) {
2706 lock_buffer(bh);
2707
2708 /*
2709 * If the buffer has the write error flag, we have failed
2710 * to write out another inode in the same block. In this
2711 * case, we don't have to read the block because we may
2712 * read the old inode data successfully.
2713 */
2714 if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
2715 set_buffer_uptodate(bh);
2716
2717 if (buffer_uptodate(bh)) {
2718 /* someone brought it uptodate while we waited */
2719 unlock_buffer(bh);
2720 goto has_buffer;
2721 }
2722
2723 /*
2724 * If we have all information of the inode in memory and this
2725 * is the only valid inode in the block, we need not read the
2726 * block.
2727 */
2728 if (in_mem) {
2729 struct buffer_head *bitmap_bh;
2730 struct ext3_group_desc *desc;
2731 int inodes_per_buffer;
2732 int inode_offset, i;
2733 int block_group;
2734 int start;
2735
2736 block_group = (inode->i_ino - 1) /
2737 EXT3_INODES_PER_GROUP(inode->i_sb);
2738 inodes_per_buffer = bh->b_size /
2739 EXT3_INODE_SIZE(inode->i_sb);
2740 inode_offset = ((inode->i_ino - 1) %
2741 EXT3_INODES_PER_GROUP(inode->i_sb));
2742 start = inode_offset & ~(inodes_per_buffer - 1);
2743
2744 /* Is the inode bitmap in cache? */
2745 desc = ext3_get_group_desc(inode->i_sb,
2746 block_group, NULL);
2747 if (!desc)
2748 goto make_io;
2749
2750 bitmap_bh = sb_getblk(inode->i_sb,
2751 le32_to_cpu(desc->bg_inode_bitmap));
2752 if (unlikely(!bitmap_bh))
2753 goto make_io;
2754
2755 /*
2756 * If the inode bitmap isn't in cache then the
2757 * optimisation may end up performing two reads instead
2758 * of one, so skip it.
2759 */
2760 if (!buffer_uptodate(bitmap_bh)) {
2761 brelse(bitmap_bh);
2762 goto make_io;
2763 }
2764 for (i = start; i < start + inodes_per_buffer; i++) {
2765 if (i == inode_offset)
2766 continue;
2767 if (ext3_test_bit(i, bitmap_bh->b_data))
2768 break;
2769 }
2770 brelse(bitmap_bh);
2771 if (i == start + inodes_per_buffer) {
2772 /* all other inodes are free, so skip I/O */
2773 memset(bh->b_data, 0, bh->b_size);
2774 set_buffer_uptodate(bh);
2775 unlock_buffer(bh);
2776 goto has_buffer;
2777 }
2778 }
2779
2780make_io:
2781 /*
2782 * There are other valid inodes in the buffer, this inode
2783 * has in-inode xattrs, or we don't have this inode in memory.
2784 * Read the block from disk.
2785 */
2786 trace_ext3_load_inode(inode);
2787 get_bh(bh);
2788 bh->b_end_io = end_buffer_read_sync;
2789 submit_bh(READ | REQ_META | REQ_PRIO, bh);
2790 wait_on_buffer(bh);
2791 if (!buffer_uptodate(bh)) {
2792 ext3_error(inode->i_sb, "ext3_get_inode_loc",
2793 "unable to read inode block - "
2794 "inode=%lu, block="E3FSBLK,
2795 inode->i_ino, block);
2796 brelse(bh);
2797 return -EIO;
2798 }
2799 }
2800has_buffer:
2801 iloc->bh = bh;
2802 return 0;
2803}
2804
2805int ext3_get_inode_loc(struct inode *inode, struct ext3_iloc *iloc)
2806{
2807 /* We have all inode data except xattrs in memory here. */
2808 return __ext3_get_inode_loc(inode, iloc,
2809 !ext3_test_inode_state(inode, EXT3_STATE_XATTR));
2810}
2811
2812void ext3_set_inode_flags(struct inode *inode)
2813{
2814 unsigned int flags = EXT3_I(inode)->i_flags;
2815
2816 inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
2817 if (flags & EXT3_SYNC_FL)
2818 inode->i_flags |= S_SYNC;
2819 if (flags & EXT3_APPEND_FL)
2820 inode->i_flags |= S_APPEND;
2821 if (flags & EXT3_IMMUTABLE_FL)
2822 inode->i_flags |= S_IMMUTABLE;
2823 if (flags & EXT3_NOATIME_FL)
2824 inode->i_flags |= S_NOATIME;
2825 if (flags & EXT3_DIRSYNC_FL)
2826 inode->i_flags |= S_DIRSYNC;
2827}
2828
2829/* Propagate flags from i_flags to EXT3_I(inode)->i_flags */
2830void ext3_get_inode_flags(struct ext3_inode_info *ei)
2831{
2832 unsigned int flags = ei->vfs_inode.i_flags;
2833
2834 ei->i_flags &= ~(EXT3_SYNC_FL|EXT3_APPEND_FL|
2835 EXT3_IMMUTABLE_FL|EXT3_NOATIME_FL|EXT3_DIRSYNC_FL);
2836 if (flags & S_SYNC)
2837 ei->i_flags |= EXT3_SYNC_FL;
2838 if (flags & S_APPEND)
2839 ei->i_flags |= EXT3_APPEND_FL;
2840 if (flags & S_IMMUTABLE)
2841 ei->i_flags |= EXT3_IMMUTABLE_FL;
2842 if (flags & S_NOATIME)
2843 ei->i_flags |= EXT3_NOATIME_FL;
2844 if (flags & S_DIRSYNC)
2845 ei->i_flags |= EXT3_DIRSYNC_FL;
2846}
2847
2848struct inode *ext3_iget(struct super_block *sb, unsigned long ino)
2849{
2850 struct ext3_iloc iloc;
2851 struct ext3_inode *raw_inode;
2852 struct ext3_inode_info *ei;
2853 struct buffer_head *bh;
2854 struct inode *inode;
2855 journal_t *journal = EXT3_SB(sb)->s_journal;
2856 transaction_t *transaction;
2857 long ret;
2858 int block;
2859 uid_t i_uid;
2860 gid_t i_gid;
2861
2862 inode = iget_locked(sb, ino);
2863 if (!inode)
2864 return ERR_PTR(-ENOMEM);
2865 if (!(inode->i_state & I_NEW))
2866 return inode;
2867
2868 ei = EXT3_I(inode);
2869 ei->i_block_alloc_info = NULL;
2870
2871 ret = __ext3_get_inode_loc(inode, &iloc, 0);
2872 if (ret < 0)
2873 goto bad_inode;
2874 bh = iloc.bh;
2875 raw_inode = ext3_raw_inode(&iloc);
2876 inode->i_mode = le16_to_cpu(raw_inode->i_mode);
2877 i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
2878 i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
2879 if(!(test_opt (inode->i_sb, NO_UID32))) {
2880 i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
2881 i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
2882 }
2883 i_uid_write(inode, i_uid);
2884 i_gid_write(inode, i_gid);
2885 set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
2886 inode->i_size = le32_to_cpu(raw_inode->i_size);
2887 inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
2888 inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
2889 inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
2890 inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = inode->i_mtime.tv_nsec = 0;
2891
2892 ei->i_state_flags = 0;
2893 ei->i_dir_start_lookup = 0;
2894 ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
2895 /* We now have enough fields to check if the inode was active or not.
2896 * This is needed because nfsd might try to access dead inodes
2897 * the test is that same one that e2fsck uses
2898 * NeilBrown 1999oct15
2899 */
2900 if (inode->i_nlink == 0) {
2901 if (inode->i_mode == 0 ||
2902 !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ORPHAN_FS)) {
2903 /* this inode is deleted */
2904 brelse (bh);
2905 ret = -ESTALE;
2906 goto bad_inode;
2907 }
2908 /* The only unlinked inodes we let through here have
2909 * valid i_mode and are being read by the orphan
2910 * recovery code: that's fine, we're about to complete
2911 * the process of deleting those. */
2912 }
2913 inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
2914 ei->i_flags = le32_to_cpu(raw_inode->i_flags);
2915#ifdef EXT3_FRAGMENTS
2916 ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
2917 ei->i_frag_no = raw_inode->i_frag;
2918 ei->i_frag_size = raw_inode->i_fsize;
2919#endif
2920 ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
2921 if (!S_ISREG(inode->i_mode)) {
2922 ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
2923 } else {
2924 inode->i_size |=
2925 ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
2926 }
2927 ei->i_disksize = inode->i_size;
2928 inode->i_generation = le32_to_cpu(raw_inode->i_generation);
2929 ei->i_block_group = iloc.block_group;
2930 /*
2931 * NOTE! The in-memory inode i_data array is in little-endian order
2932 * even on big-endian machines: we do NOT byteswap the block numbers!
2933 */
2934 for (block = 0; block < EXT3_N_BLOCKS; block++)
2935 ei->i_data[block] = raw_inode->i_block[block];
2936 INIT_LIST_HEAD(&ei->i_orphan);
2937
2938 /*
2939 * Set transaction id's of transactions that have to be committed
2940 * to finish f[data]sync. We set them to currently running transaction
2941 * as we cannot be sure that the inode or some of its metadata isn't
2942 * part of the transaction - the inode could have been reclaimed and
2943 * now it is reread from disk.
2944 */
2945 if (journal) {
2946 tid_t tid;
2947
2948 spin_lock(&journal->j_state_lock);
2949 if (journal->j_running_transaction)
2950 transaction = journal->j_running_transaction;
2951 else
2952 transaction = journal->j_committing_transaction;
2953 if (transaction)
2954 tid = transaction->t_tid;
2955 else
2956 tid = journal->j_commit_sequence;
2957 spin_unlock(&journal->j_state_lock);
2958 atomic_set(&ei->i_sync_tid, tid);
2959 atomic_set(&ei->i_datasync_tid, tid);
2960 }
2961
2962 if (inode->i_ino >= EXT3_FIRST_INO(inode->i_sb) + 1 &&
2963 EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) {
2964 /*
2965 * When mke2fs creates big inodes it does not zero out
2966 * the unused bytes above EXT3_GOOD_OLD_INODE_SIZE,
2967 * so ignore those first few inodes.
2968 */
2969 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
2970 if (EXT3_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
2971 EXT3_INODE_SIZE(inode->i_sb)) {
2972 brelse (bh);
2973 ret = -EIO;
2974 goto bad_inode;
2975 }
2976 if (ei->i_extra_isize == 0) {
2977 /* The extra space is currently unused. Use it. */
2978 ei->i_extra_isize = sizeof(struct ext3_inode) -
2979 EXT3_GOOD_OLD_INODE_SIZE;
2980 } else {
2981 __le32 *magic = (void *)raw_inode +
2982 EXT3_GOOD_OLD_INODE_SIZE +
2983 ei->i_extra_isize;
2984 if (*magic == cpu_to_le32(EXT3_XATTR_MAGIC))
2985 ext3_set_inode_state(inode, EXT3_STATE_XATTR);
2986 }
2987 } else
2988 ei->i_extra_isize = 0;
2989
2990 if (S_ISREG(inode->i_mode)) {
2991 inode->i_op = &ext3_file_inode_operations;
2992 inode->i_fop = &ext3_file_operations;
2993 ext3_set_aops(inode);
2994 } else if (S_ISDIR(inode->i_mode)) {
2995 inode->i_op = &ext3_dir_inode_operations;
2996 inode->i_fop = &ext3_dir_operations;
2997 } else if (S_ISLNK(inode->i_mode)) {
2998 if (ext3_inode_is_fast_symlink(inode)) {
2999 inode->i_op = &ext3_fast_symlink_inode_operations;
3000 nd_terminate_link(ei->i_data, inode->i_size,
3001 sizeof(ei->i_data) - 1);
3002 inode->i_link = (char *)ei->i_data;
3003 } else {
3004 inode->i_op = &ext3_symlink_inode_operations;
3005 ext3_set_aops(inode);
3006 }
3007 } else {
3008 inode->i_op = &ext3_special_inode_operations;
3009 if (raw_inode->i_block[0])
3010 init_special_inode(inode, inode->i_mode,
3011 old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
3012 else
3013 init_special_inode(inode, inode->i_mode,
3014 new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
3015 }
3016 brelse (iloc.bh);
3017 ext3_set_inode_flags(inode);
3018 unlock_new_inode(inode);
3019 return inode;
3020
3021bad_inode:
3022 iget_failed(inode);
3023 return ERR_PTR(ret);
3024}
3025
3026/*
3027 * Post the struct inode info into an on-disk inode location in the
3028 * buffer-cache. This gobbles the caller's reference to the
3029 * buffer_head in the inode location struct.
3030 *
3031 * The caller must have write access to iloc->bh.
3032 */
3033static int ext3_do_update_inode(handle_t *handle,
3034 struct inode *inode,
3035 struct ext3_iloc *iloc)
3036{
3037 struct ext3_inode *raw_inode = ext3_raw_inode(iloc);
3038 struct ext3_inode_info *ei = EXT3_I(inode);
3039 struct buffer_head *bh = iloc->bh;
3040 int err = 0, rc, block;
3041 int need_datasync = 0;
3042 __le32 disksize;
3043 uid_t i_uid;
3044 gid_t i_gid;
3045
3046again:
3047 /* we can't allow multiple procs in here at once, its a bit racey */
3048 lock_buffer(bh);
3049
3050 /* For fields not not tracking in the in-memory inode,
3051 * initialise them to zero for new inodes. */
3052 if (ext3_test_inode_state(inode, EXT3_STATE_NEW))
3053 memset(raw_inode, 0, EXT3_SB(inode->i_sb)->s_inode_size);
3054
3055 ext3_get_inode_flags(ei);
3056 raw_inode->i_mode = cpu_to_le16(inode->i_mode);
3057 i_uid = i_uid_read(inode);
3058 i_gid = i_gid_read(inode);
3059 if(!(test_opt(inode->i_sb, NO_UID32))) {
3060 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(i_uid));
3061 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(i_gid));
3062/*
3063 * Fix up interoperability with old kernels. Otherwise, old inodes get
3064 * re-used with the upper 16 bits of the uid/gid intact
3065 */
3066 if(!ei->i_dtime) {
3067 raw_inode->i_uid_high =
3068 cpu_to_le16(high_16_bits(i_uid));
3069 raw_inode->i_gid_high =
3070 cpu_to_le16(high_16_bits(i_gid));
3071 } else {
3072 raw_inode->i_uid_high = 0;
3073 raw_inode->i_gid_high = 0;
3074 }
3075 } else {
3076 raw_inode->i_uid_low =
3077 cpu_to_le16(fs_high2lowuid(i_uid));
3078 raw_inode->i_gid_low =
3079 cpu_to_le16(fs_high2lowgid(i_gid));
3080 raw_inode->i_uid_high = 0;
3081 raw_inode->i_gid_high = 0;
3082 }
3083 raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
3084 disksize = cpu_to_le32(ei->i_disksize);
3085 if (disksize != raw_inode->i_size) {
3086 need_datasync = 1;
3087 raw_inode->i_size = disksize;
3088 }
3089 raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
3090 raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
3091 raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
3092 raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
3093 raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
3094 raw_inode->i_flags = cpu_to_le32(ei->i_flags);
3095#ifdef EXT3_FRAGMENTS
3096 raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
3097 raw_inode->i_frag = ei->i_frag_no;
3098 raw_inode->i_fsize = ei->i_frag_size;
3099#endif
3100 raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
3101 if (!S_ISREG(inode->i_mode)) {
3102 raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
3103 } else {
3104 disksize = cpu_to_le32(ei->i_disksize >> 32);
3105 if (disksize != raw_inode->i_size_high) {
3106 raw_inode->i_size_high = disksize;
3107 need_datasync = 1;
3108 }
3109 if (ei->i_disksize > 0x7fffffffULL) {
3110 struct super_block *sb = inode->i_sb;
3111 if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
3112 EXT3_FEATURE_RO_COMPAT_LARGE_FILE) ||
3113 EXT3_SB(sb)->s_es->s_rev_level ==
3114 cpu_to_le32(EXT3_GOOD_OLD_REV)) {
3115 /* If this is the first large file
3116 * created, add a flag to the superblock.
3117 */
3118 unlock_buffer(bh);
3119 err = ext3_journal_get_write_access(handle,
3120 EXT3_SB(sb)->s_sbh);
3121 if (err)
3122 goto out_brelse;
3123
3124 ext3_update_dynamic_rev(sb);
3125 EXT3_SET_RO_COMPAT_FEATURE(sb,
3126 EXT3_FEATURE_RO_COMPAT_LARGE_FILE);
3127 handle->h_sync = 1;
3128 err = ext3_journal_dirty_metadata(handle,
3129 EXT3_SB(sb)->s_sbh);
3130 /* get our lock and start over */
3131 goto again;
3132 }
3133 }
3134 }
3135 raw_inode->i_generation = cpu_to_le32(inode->i_generation);
3136 if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
3137 if (old_valid_dev(inode->i_rdev)) {
3138 raw_inode->i_block[0] =
3139 cpu_to_le32(old_encode_dev(inode->i_rdev));
3140 raw_inode->i_block[1] = 0;
3141 } else {
3142 raw_inode->i_block[0] = 0;
3143 raw_inode->i_block[1] =
3144 cpu_to_le32(new_encode_dev(inode->i_rdev));
3145 raw_inode->i_block[2] = 0;
3146 }
3147 } else for (block = 0; block < EXT3_N_BLOCKS; block++)
3148 raw_inode->i_block[block] = ei->i_data[block];
3149
3150 if (ei->i_extra_isize)
3151 raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
3152
3153 BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
3154 unlock_buffer(bh);
3155 rc = ext3_journal_dirty_metadata(handle, bh);
3156 if (!err)
3157 err = rc;
3158 ext3_clear_inode_state(inode, EXT3_STATE_NEW);
3159
3160 atomic_set(&ei->i_sync_tid, handle->h_transaction->t_tid);
3161 if (need_datasync)
3162 atomic_set(&ei->i_datasync_tid, handle->h_transaction->t_tid);
3163out_brelse:
3164 brelse (bh);
3165 ext3_std_error(inode->i_sb, err);
3166 return err;
3167}
3168
3169/*
3170 * ext3_write_inode()
3171 *
3172 * We are called from a few places:
3173 *
3174 * - Within generic_file_aio_write() -> generic_write_sync() for O_SYNC files.
3175 * Here, there will be no transaction running. We wait for any running
3176 * transaction to commit.
3177 *
3178 * - Within flush work (for sys_sync(), kupdate and such).
3179 * We wait on commit, if told to.
3180 *
3181 * - Within iput_final() -> write_inode_now()
3182 * We wait on commit, if told to.
3183 *
3184 * In all cases it is actually safe for us to return without doing anything,
3185 * because the inode has been copied into a raw inode buffer in
3186 * ext3_mark_inode_dirty(). This is a correctness thing for WB_SYNC_ALL
3187 * writeback.
3188 *
3189 * Note that we are absolutely dependent upon all inode dirtiers doing the
3190 * right thing: they *must* call mark_inode_dirty() after dirtying info in
3191 * which we are interested.
3192 *
3193 * It would be a bug for them to not do this. The code:
3194 *
3195 * mark_inode_dirty(inode)
3196 * stuff();
3197 * inode->i_size = expr;
3198 *
3199 * is in error because write_inode() could occur while `stuff()' is running,
3200 * and the new i_size will be lost. Plus the inode will no longer be on the
3201 * superblock's dirty inode list.
3202 */
3203int ext3_write_inode(struct inode *inode, struct writeback_control *wbc)
3204{
3205 if (WARN_ON_ONCE(current->flags & PF_MEMALLOC))
3206 return 0;
3207
3208 if (ext3_journal_current_handle()) {
3209 jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
3210 dump_stack();
3211 return -EIO;
3212 }
3213
3214 /*
3215 * No need to force transaction in WB_SYNC_NONE mode. Also
3216 * ext3_sync_fs() will force the commit after everything is
3217 * written.
3218 */
3219 if (wbc->sync_mode != WB_SYNC_ALL || wbc->for_sync)
3220 return 0;
3221
3222 return ext3_force_commit(inode->i_sb);
3223}
3224
3225/*
3226 * ext3_setattr()
3227 *
3228 * Called from notify_change.
3229 *
3230 * We want to trap VFS attempts to truncate the file as soon as
3231 * possible. In particular, we want to make sure that when the VFS
3232 * shrinks i_size, we put the inode on the orphan list and modify
3233 * i_disksize immediately, so that during the subsequent flushing of
3234 * dirty pages and freeing of disk blocks, we can guarantee that any
3235 * commit will leave the blocks being flushed in an unused state on
3236 * disk. (On recovery, the inode will get truncated and the blocks will
3237 * be freed, so we have a strong guarantee that no future commit will
3238 * leave these blocks visible to the user.)
3239 *
3240 * Called with inode->sem down.
3241 */
3242int ext3_setattr(struct dentry *dentry, struct iattr *attr)
3243{
3244 struct inode *inode = d_inode(dentry);
3245 int error, rc = 0;
3246 const unsigned int ia_valid = attr->ia_valid;
3247
3248 error = inode_change_ok(inode, attr);
3249 if (error)
3250 return error;
3251
3252 if (is_quota_modification(inode, attr))
3253 dquot_initialize(inode);
3254 if ((ia_valid & ATTR_UID && !uid_eq(attr->ia_uid, inode->i_uid)) ||
3255 (ia_valid & ATTR_GID && !gid_eq(attr->ia_gid, inode->i_gid))) {
3256 handle_t *handle;
3257
3258 /* (user+group)*(old+new) structure, inode write (sb,
3259 * inode block, ? - but truncate inode update has it) */
3260 handle = ext3_journal_start(inode, EXT3_MAXQUOTAS_INIT_BLOCKS(inode->i_sb)+
3261 EXT3_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)+3);
3262 if (IS_ERR(handle)) {
3263 error = PTR_ERR(handle);
3264 goto err_out;
3265 }
3266 error = dquot_transfer(inode, attr);
3267 if (error) {
3268 ext3_journal_stop(handle);
3269 return error;
3270 }
3271 /* Update corresponding info in inode so that everything is in
3272 * one transaction */
3273 if (attr->ia_valid & ATTR_UID)
3274 inode->i_uid = attr->ia_uid;
3275 if (attr->ia_valid & ATTR_GID)
3276 inode->i_gid = attr->ia_gid;
3277 error = ext3_mark_inode_dirty(handle, inode);
3278 ext3_journal_stop(handle);
3279 }
3280
3281 if (attr->ia_valid & ATTR_SIZE)
3282 inode_dio_wait(inode);
3283
3284 if (S_ISREG(inode->i_mode) &&
3285 attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
3286 handle_t *handle;
3287
3288 handle = ext3_journal_start(inode, 3);
3289 if (IS_ERR(handle)) {
3290 error = PTR_ERR(handle);
3291 goto err_out;
3292 }
3293
3294 error = ext3_orphan_add(handle, inode);
3295 if (error) {
3296 ext3_journal_stop(handle);
3297 goto err_out;
3298 }
3299 EXT3_I(inode)->i_disksize = attr->ia_size;
3300 error = ext3_mark_inode_dirty(handle, inode);
3301 ext3_journal_stop(handle);
3302 if (error) {
3303 /* Some hard fs error must have happened. Bail out. */
3304 ext3_orphan_del(NULL, inode);
3305 goto err_out;
3306 }
3307 rc = ext3_block_truncate_page(inode, attr->ia_size);
3308 if (rc) {
3309 /* Cleanup orphan list and exit */
3310 handle = ext3_journal_start(inode, 3);
3311 if (IS_ERR(handle)) {
3312 ext3_orphan_del(NULL, inode);
3313 goto err_out;
3314 }
3315 ext3_orphan_del(handle, inode);
3316 ext3_journal_stop(handle);
3317 goto err_out;
3318 }
3319 }
3320
3321 if ((attr->ia_valid & ATTR_SIZE) &&
3322 attr->ia_size != i_size_read(inode)) {
3323 truncate_setsize(inode, attr->ia_size);
3324 ext3_truncate(inode);
3325 }
3326
3327 setattr_copy(inode, attr);
3328 mark_inode_dirty(inode);
3329
3330 if (ia_valid & ATTR_MODE)
3331 rc = posix_acl_chmod(inode, inode->i_mode);
3332
3333err_out:
3334 ext3_std_error(inode->i_sb, error);
3335 if (!error)
3336 error = rc;
3337 return error;
3338}
3339
3340
3341/*
3342 * How many blocks doth make a writepage()?
3343 *
3344 * With N blocks per page, it may be:
3345 * N data blocks
3346 * 2 indirect block
3347 * 2 dindirect
3348 * 1 tindirect
3349 * N+5 bitmap blocks (from the above)
3350 * N+5 group descriptor summary blocks
3351 * 1 inode block
3352 * 1 superblock.
3353 * 2 * EXT3_SINGLEDATA_TRANS_BLOCKS for the quote files
3354 *
3355 * 3 * (N + 5) + 2 + 2 * EXT3_SINGLEDATA_TRANS_BLOCKS
3356 *
3357 * With ordered or writeback data it's the same, less the N data blocks.
3358 *
3359 * If the inode's direct blocks can hold an integral number of pages then a
3360 * page cannot straddle two indirect blocks, and we can only touch one indirect
3361 * and dindirect block, and the "5" above becomes "3".
3362 *
3363 * This still overestimates under most circumstances. If we were to pass the
3364 * start and end offsets in here as well we could do block_to_path() on each
3365 * block and work out the exact number of indirects which are touched. Pah.
3366 */
3367
3368static int ext3_writepage_trans_blocks(struct inode *inode)
3369{
3370 int bpp = ext3_journal_blocks_per_page(inode);
3371 int indirects = (EXT3_NDIR_BLOCKS % bpp) ? 5 : 3;
3372 int ret;
3373
3374 if (ext3_should_journal_data(inode))
3375 ret = 3 * (bpp + indirects) + 2;
3376 else
3377 ret = 2 * (bpp + indirects) + indirects + 2;
3378
3379#ifdef CONFIG_QUOTA
3380 /* We know that structure was already allocated during dquot_initialize so
3381 * we will be updating only the data blocks + inodes */
3382 ret += EXT3_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
3383#endif
3384
3385 return ret;
3386}
3387
3388/*
3389 * The caller must have previously called ext3_reserve_inode_write().
3390 * Give this, we know that the caller already has write access to iloc->bh.
3391 */
3392int ext3_mark_iloc_dirty(handle_t *handle,
3393 struct inode *inode, struct ext3_iloc *iloc)
3394{
3395 int err = 0;
3396
3397 /* the do_update_inode consumes one bh->b_count */
3398 get_bh(iloc->bh);
3399
3400 /* ext3_do_update_inode() does journal_dirty_metadata */
3401 err = ext3_do_update_inode(handle, inode, iloc);
3402 put_bh(iloc->bh);
3403 return err;
3404}
3405
3406/*
3407 * On success, We end up with an outstanding reference count against
3408 * iloc->bh. This _must_ be cleaned up later.
3409 */
3410
3411int
3412ext3_reserve_inode_write(handle_t *handle, struct inode *inode,
3413 struct ext3_iloc *iloc)
3414{
3415 int err = 0;
3416 if (handle) {
3417 err = ext3_get_inode_loc(inode, iloc);
3418 if (!err) {
3419 BUFFER_TRACE(iloc->bh, "get_write_access");
3420 err = ext3_journal_get_write_access(handle, iloc->bh);
3421 if (err) {
3422 brelse(iloc->bh);
3423 iloc->bh = NULL;
3424 }
3425 }
3426 }
3427 ext3_std_error(inode->i_sb, err);
3428 return err;
3429}
3430
3431/*
3432 * What we do here is to mark the in-core inode as clean with respect to inode
3433 * dirtiness (it may still be data-dirty).
3434 * This means that the in-core inode may be reaped by prune_icache
3435 * without having to perform any I/O. This is a very good thing,
3436 * because *any* task may call prune_icache - even ones which
3437 * have a transaction open against a different journal.
3438 *
3439 * Is this cheating? Not really. Sure, we haven't written the
3440 * inode out, but prune_icache isn't a user-visible syncing function.
3441 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
3442 * we start and wait on commits.
3443 */
3444int ext3_mark_inode_dirty(handle_t *handle, struct inode *inode)
3445{
3446 struct ext3_iloc iloc;
3447 int err;
3448
3449 might_sleep();
3450 trace_ext3_mark_inode_dirty(inode, _RET_IP_);
3451 err = ext3_reserve_inode_write(handle, inode, &iloc);
3452 if (!err)
3453 err = ext3_mark_iloc_dirty(handle, inode, &iloc);
3454 return err;
3455}
3456
3457/*
3458 * ext3_dirty_inode() is called from __mark_inode_dirty()
3459 *
3460 * We're really interested in the case where a file is being extended.
3461 * i_size has been changed by generic_commit_write() and we thus need
3462 * to include the updated inode in the current transaction.
3463 *
3464 * Also, dquot_alloc_space() will always dirty the inode when blocks
3465 * are allocated to the file.
3466 *
3467 * If the inode is marked synchronous, we don't honour that here - doing
3468 * so would cause a commit on atime updates, which we don't bother doing.
3469 * We handle synchronous inodes at the highest possible level.
3470 */
3471void ext3_dirty_inode(struct inode *inode, int flags)
3472{
3473 handle_t *current_handle = ext3_journal_current_handle();
3474 handle_t *handle;
3475
3476 handle = ext3_journal_start(inode, 2);
3477 if (IS_ERR(handle))
3478 goto out;
3479 if (current_handle &&
3480 current_handle->h_transaction != handle->h_transaction) {
3481 /* This task has a transaction open against a different fs */
3482 printk(KERN_EMERG "%s: transactions do not match!\n",
3483 __func__);
3484 } else {
3485 jbd_debug(5, "marking dirty. outer handle=%p\n",
3486 current_handle);
3487 ext3_mark_inode_dirty(handle, inode);
3488 }
3489 ext3_journal_stop(handle);
3490out:
3491 return;
3492}
3493
3494#if 0
3495/*
3496 * Bind an inode's backing buffer_head into this transaction, to prevent
3497 * it from being flushed to disk early. Unlike
3498 * ext3_reserve_inode_write, this leaves behind no bh reference and
3499 * returns no iloc structure, so the caller needs to repeat the iloc
3500 * lookup to mark the inode dirty later.
3501 */
3502static int ext3_pin_inode(handle_t *handle, struct inode *inode)
3503{
3504 struct ext3_iloc iloc;
3505
3506 int err = 0;
3507 if (handle) {
3508 err = ext3_get_inode_loc(inode, &iloc);
3509 if (!err) {
3510 BUFFER_TRACE(iloc.bh, "get_write_access");
3511 err = journal_get_write_access(handle, iloc.bh);
3512 if (!err)
3513 err = ext3_journal_dirty_metadata(handle,
3514 iloc.bh);
3515 brelse(iloc.bh);
3516 }
3517 }
3518 ext3_std_error(inode->i_sb, err);
3519 return err;
3520}
3521#endif
3522
3523int ext3_change_inode_journal_flag(struct inode *inode, int val)
3524{
3525 journal_t *journal;
3526 handle_t *handle;
3527 int err;
3528
3529 /*
3530 * We have to be very careful here: changing a data block's
3531 * journaling status dynamically is dangerous. If we write a
3532 * data block to the journal, change the status and then delete
3533 * that block, we risk forgetting to revoke the old log record
3534 * from the journal and so a subsequent replay can corrupt data.
3535 * So, first we make sure that the journal is empty and that
3536 * nobody is changing anything.
3537 */
3538
3539 journal = EXT3_JOURNAL(inode);
3540 if (is_journal_aborted(journal))
3541 return -EROFS;
3542
3543 journal_lock_updates(journal);
3544 journal_flush(journal);
3545
3546 /*
3547 * OK, there are no updates running now, and all cached data is
3548 * synced to disk. We are now in a completely consistent state
3549 * which doesn't have anything in the journal, and we know that
3550 * no filesystem updates are running, so it is safe to modify
3551 * the inode's in-core data-journaling state flag now.
3552 */
3553
3554 if (val)
3555 EXT3_I(inode)->i_flags |= EXT3_JOURNAL_DATA_FL;
3556 else
3557 EXT3_I(inode)->i_flags &= ~EXT3_JOURNAL_DATA_FL;
3558 ext3_set_aops(inode);
3559
3560 journal_unlock_updates(journal);
3561
3562 /* Finally we can mark the inode as dirty. */
3563
3564 handle = ext3_journal_start(inode, 1);
3565 if (IS_ERR(handle))
3566 return PTR_ERR(handle);
3567
3568 err = ext3_mark_inode_dirty(handle, inode);
3569 handle->h_sync = 1;
3570 ext3_journal_stop(handle);
3571 ext3_std_error(inode->i_sb, err);
3572
3573 return err;
3574}
generated by cgit v1.2.2 (git 2.25.0) at 2025-10-03 04:12:44 -0400