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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/module.h>
26#include <linux/fs.h>
27#include <linux/time.h>
28#include <linux/ext3_jbd.h>
29#include <linux/jbd.h>
30#include <linux/highuid.h>
31#include <linux/pagemap.h>
32#include <linux/quotaops.h>
33#include <linux/string.h>
34#include <linux/buffer_head.h>
35#include <linux/writeback.h>
36#include <linux/mpage.h>
37#include <linux/uio.h>
38#include <linux/bio.h>
39#include <linux/fiemap.h>
40#include <linux/namei.h>
41#include <trace/events/ext3.h>
42#include "xattr.h"
43#include "acl.h"
44
45static int ext3_writepage_trans_blocks(struct inode *inode);
46static int ext3_block_truncate_page(struct inode *inode, loff_t from);
47
48/*
49 * Test whether an inode is a fast symlink.
50 */
51static int ext3_inode_is_fast_symlink(struct inode *inode)
52{
53 int ea_blocks = EXT3_I(inode)->i_file_acl ?
54 (inode->i_sb->s_blocksize >> 9) : 0;
55
56 return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
57}
58
59/*
60 * The ext3 forget function must perform a revoke if we are freeing data
61 * which has been journaled. Metadata (eg. indirect blocks) must be
62 * revoked in all cases.
63 *
64 * "bh" may be NULL: a metadata block may have been freed from memory
65 * but there may still be a record of it in the journal, and that record
66 * still needs to be revoked.
67 */
68int ext3_forget(handle_t *handle, int is_metadata, struct inode *inode,
69 struct buffer_head *bh, ext3_fsblk_t blocknr)
70{
71 int err;
72
73 might_sleep();
74
75 trace_ext3_forget(inode, is_metadata, blocknr);
76 BUFFER_TRACE(bh, "enter");
77
78 jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
79 "data mode %lx\n",
80 bh, is_metadata, inode->i_mode,
81 test_opt(inode->i_sb, DATA_FLAGS));
82
83 /* Never use the revoke function if we are doing full data
84 * journaling: there is no need to, and a V1 superblock won't
85 * support it. Otherwise, only skip the revoke on un-journaled
86 * data blocks. */
87
88 if (test_opt(inode->i_sb, DATA_FLAGS) == EXT3_MOUNT_JOURNAL_DATA ||
89 (!is_metadata && !ext3_should_journal_data(inode))) {
90 if (bh) {
91 BUFFER_TRACE(bh, "call journal_forget");
92 return ext3_journal_forget(handle, bh);
93 }
94 return 0;
95 }
96
97 /*
98 * data!=journal && (is_metadata || should_journal_data(inode))
99 */
100 BUFFER_TRACE(bh, "call ext3_journal_revoke");
101 err = ext3_journal_revoke(handle, blocknr, bh);
102 if (err)
103 ext3_abort(inode->i_sb, __func__,
104 "error %d when attempting revoke", err);
105 BUFFER_TRACE(bh, "exit");
106 return err;
107}
108
109/*
110 * Work out how many blocks we need to proceed with the next chunk of a
111 * truncate transaction.
112 */
113static unsigned long blocks_for_truncate(struct inode *inode)
114{
115 unsigned long needed;
116
117 needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
118
119 /* Give ourselves just enough room to cope with inodes in which
120 * i_blocks is corrupt: we've seen disk corruptions in the past
121 * which resulted in random data in an inode which looked enough
122 * like a regular file for ext3 to try to delete it. Things
123 * will go a bit crazy if that happens, but at least we should
124 * try not to panic the whole kernel. */
125 if (needed < 2)
126 needed = 2;
127
128 /* But we need to bound the transaction so we don't overflow the
129 * journal. */
130 if (needed > EXT3_MAX_TRANS_DATA)
131 needed = EXT3_MAX_TRANS_DATA;
132
133 return EXT3_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
134}
135
136/*
137 * Truncate transactions can be complex and absolutely huge. So we need to
138 * be able to restart the transaction at a conventient checkpoint to make
139 * sure we don't overflow the journal.
140 *
141 * start_transaction gets us a new handle for a truncate transaction,
142 * and extend_transaction tries to extend the existing one a bit. If
143 * extend fails, we need to propagate the failure up and restart the
144 * transaction in the top-level truncate loop. --sct
145 */
146static handle_t *start_transaction(struct inode *inode)
147{
148 handle_t *result;
149
150 result = ext3_journal_start(inode, blocks_for_truncate(inode));
151 if (!IS_ERR(result))
152 return result;
153
154 ext3_std_error(inode->i_sb, PTR_ERR(result));
155 return result;
156}
157
158/*
159 * Try to extend this transaction for the purposes of truncation.
160 *
161 * Returns 0 if we managed to create more room. If we can't create more
162 * room, and the transaction must be restarted we return 1.
163 */
164static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
165{
166 if (handle->h_buffer_credits > EXT3_RESERVE_TRANS_BLOCKS)
167 return 0;
168 if (!ext3_journal_extend(handle, blocks_for_truncate(inode)))
169 return 0;
170 return 1;
171}
172
173/*
174 * Restart the transaction associated with *handle. This does a commit,
175 * so before we call here everything must be consistently dirtied against
176 * this transaction.
177 */
178static int truncate_restart_transaction(handle_t *handle, struct inode *inode)
179{
180 int ret;
181
182 jbd_debug(2, "restarting handle %p\n", handle);
183 /*
184 * Drop truncate_mutex to avoid deadlock with ext3_get_blocks_handle
185 * At this moment, get_block can be called only for blocks inside
186 * i_size since page cache has been already dropped and writes are
187 * blocked by i_mutex. So we can safely drop the truncate_mutex.
188 */
189 mutex_unlock(&EXT3_I(inode)->truncate_mutex);
190 ret = ext3_journal_restart(handle, blocks_for_truncate(inode));
191 mutex_lock(&EXT3_I(inode)->truncate_mutex);
192 return ret;
193}
194
195/*
196 * Called at inode eviction from icache
197 */
198void ext3_evict_inode (struct inode *inode)
199{
200 struct ext3_inode_info *ei = EXT3_I(inode);
201 struct ext3_block_alloc_info *rsv;
202 handle_t *handle;
203 int want_delete = 0;
204
205 trace_ext3_evict_inode(inode);
206 if (!inode->i_nlink && !is_bad_inode(inode)) {
207 dquot_initialize(inode);
208 want_delete = 1;
209 }
210
211 /*
212 * When journalling data dirty buffers are tracked only in the journal.
213 * So although mm thinks everything is clean and ready for reaping the
214 * inode might still have some pages to write in the running
215 * transaction or waiting to be checkpointed. Thus calling
216 * journal_invalidatepage() (via truncate_inode_pages()) to discard
217 * these buffers can cause data loss. Also even if we did not discard
218 * these buffers, we would have no way to find them after the inode
219 * is reaped and thus user could see stale data if he tries to read
220 * them before the transaction is checkpointed. So be careful and
221 * force everything to disk here... We use ei->i_datasync_tid to
222 * store the newest transaction containing inode's data.
223 *
224 * Note that directories do not have this problem because they don't
225 * use page cache.
226 */
227 if (inode->i_nlink && ext3_should_journal_data(inode) &&
228 (S_ISLNK(inode->i_mode) || S_ISREG(inode->i_mode))) {
229 tid_t commit_tid = atomic_read(&ei->i_datasync_tid);
230 journal_t *journal = EXT3_SB(inode->i_sb)->s_journal;
231
232 log_start_commit(journal, commit_tid);
233 log_wait_commit(journal, commit_tid);
234 filemap_write_and_wait(&inode->i_data);
235 }
236 truncate_inode_pages(&inode->i_data, 0);
237
238 ext3_discard_reservation(inode);
239 rsv = ei->i_block_alloc_info;
240 ei->i_block_alloc_info = NULL;
241 if (unlikely(rsv))
242 kfree(rsv);
243
244 if (!want_delete)
245 goto no_delete;
246
247 handle = start_transaction(inode);
248 if (IS_ERR(handle)) {
249 /*
250 * If we're going to skip the normal cleanup, we still need to
251 * make sure that the in-core orphan linked list is properly
252 * cleaned up.
253 */
254 ext3_orphan_del(NULL, inode);
255 goto no_delete;
256 }
257
258 if (IS_SYNC(inode))
259 handle->h_sync = 1;
260 inode->i_size = 0;
261 if (inode->i_blocks)
262 ext3_truncate(inode);
263 /*
264 * Kill off the orphan record created when the inode lost the last
265 * link. Note that ext3_orphan_del() has to be able to cope with the
266 * deletion of a non-existent orphan - ext3_truncate() could
267 * have removed the record.
268 */
269 ext3_orphan_del(handle, inode);
270 ei->i_dtime = get_seconds();
271
272 /*
273 * One subtle ordering requirement: if anything has gone wrong
274 * (transaction abort, IO errors, whatever), then we can still
275 * do these next steps (the fs will already have been marked as
276 * having errors), but we can't free the inode if the mark_dirty
277 * fails.
278 */
279 if (ext3_mark_inode_dirty(handle, inode)) {
280 /* If that failed, just dquot_drop() and be done with that */
281 dquot_drop(inode);
282 end_writeback(inode);
283 } else {
284 ext3_xattr_delete_inode(handle, inode);
285 dquot_free_inode(inode);
286 dquot_drop(inode);
287 end_writeback(inode);
288 ext3_free_inode(handle, inode);
289 }
290 ext3_journal_stop(handle);
291 return;
292no_delete:
293 end_writeback(inode);
294 dquot_drop(inode);
295}
296
297typedef struct {
298 __le32 *p;
299 __le32 key;
300 struct buffer_head *bh;
301} Indirect;
302
303static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
304{
305 p->key = *(p->p = v);
306 p->bh = bh;
307}
308
309static int verify_chain(Indirect *from, Indirect *to)
310{
311 while (from <= to && from->key == *from->p)
312 from++;
313 return (from > to);
314}
315
316/**
317 * ext3_block_to_path - parse the block number into array of offsets
318 * @inode: inode in question (we are only interested in its superblock)
319 * @i_block: block number to be parsed
320 * @offsets: array to store the offsets in
321 * @boundary: set this non-zero if the referred-to block is likely to be
322 * followed (on disk) by an indirect block.
323 *
324 * To store the locations of file's data ext3 uses a data structure common
325 * for UNIX filesystems - tree of pointers anchored in the inode, with
326 * data blocks at leaves and indirect blocks in intermediate nodes.
327 * This function translates the block number into path in that tree -
328 * return value is the path length and @offsets[n] is the offset of
329 * pointer to (n+1)th node in the nth one. If @block is out of range
330 * (negative or too large) warning is printed and zero returned.
331 *
332 * Note: function doesn't find node addresses, so no IO is needed. All
333 * we need to know is the capacity of indirect blocks (taken from the
334 * inode->i_sb).
335 */
336
337/*
338 * Portability note: the last comparison (check that we fit into triple
339 * indirect block) is spelled differently, because otherwise on an
340 * architecture with 32-bit longs and 8Kb pages we might get into trouble
341 * if our filesystem had 8Kb blocks. We might use long long, but that would
342 * kill us on x86. Oh, well, at least the sign propagation does not matter -
343 * i_block would have to be negative in the very beginning, so we would not
344 * get there at all.
345 */
346
347static int ext3_block_to_path(struct inode *inode,
348 long i_block, int offsets[4], int *boundary)
349{
350 int ptrs = EXT3_ADDR_PER_BLOCK(inode->i_sb);
351 int ptrs_bits = EXT3_ADDR_PER_BLOCK_BITS(inode->i_sb);
352 const long direct_blocks = EXT3_NDIR_BLOCKS,
353 indirect_blocks = ptrs,
354 double_blocks = (1 << (ptrs_bits * 2));
355 int n = 0;
356 int final = 0;
357
358 if (i_block < 0) {
359 ext3_warning (inode->i_sb, "ext3_block_to_path", "block < 0");
360 } else if (i_block < direct_blocks) {
361 offsets[n++] = i_block;
362 final = direct_blocks;
363 } else if ( (i_block -= direct_blocks) < indirect_blocks) {
364 offsets[n++] = EXT3_IND_BLOCK;
365 offsets[n++] = i_block;
366 final = ptrs;
367 } else if ((i_block -= indirect_blocks) < double_blocks) {
368 offsets[n++] = EXT3_DIND_BLOCK;
369 offsets[n++] = i_block >> ptrs_bits;
370 offsets[n++] = i_block & (ptrs - 1);
371 final = ptrs;
372 } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
373 offsets[n++] = EXT3_TIND_BLOCK;
374 offsets[n++] = i_block >> (ptrs_bits * 2);
375 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
376 offsets[n++] = i_block & (ptrs - 1);
377 final = ptrs;
378 } else {
379 ext3_warning(inode->i_sb, "ext3_block_to_path", "block > big");
380 }
381 if (boundary)
382 *boundary = final - 1 - (i_block & (ptrs - 1));
383 return n;
384}
385
386/**
387 * ext3_get_branch - read the chain of indirect blocks leading to data
388 * @inode: inode in question
389 * @depth: depth of the chain (1 - direct pointer, etc.)
390 * @offsets: offsets of pointers in inode/indirect blocks
391 * @chain: place to store the result
392 * @err: here we store the error value
393 *
394 * Function fills the array of triples <key, p, bh> and returns %NULL
395 * if everything went OK or the pointer to the last filled triple
396 * (incomplete one) otherwise. Upon the return chain[i].key contains
397 * the number of (i+1)-th block in the chain (as it is stored in memory,
398 * i.e. little-endian 32-bit), chain[i].p contains the address of that
399 * number (it points into struct inode for i==0 and into the bh->b_data
400 * for i>0) and chain[i].bh points to the buffer_head of i-th indirect
401 * block for i>0 and NULL for i==0. In other words, it holds the block
402 * numbers of the chain, addresses they were taken from (and where we can
403 * verify that chain did not change) and buffer_heads hosting these
404 * numbers.
405 *
406 * Function stops when it stumbles upon zero pointer (absent block)
407 * (pointer to last triple returned, *@err == 0)
408 * or when it gets an IO error reading an indirect block
409 * (ditto, *@err == -EIO)
410 * or when it notices that chain had been changed while it was reading
411 * (ditto, *@err == -EAGAIN)
412 * or when it reads all @depth-1 indirect blocks successfully and finds
413 * the whole chain, all way to the data (returns %NULL, *err == 0).
414 */
415static Indirect *ext3_get_branch(struct inode *inode, int depth, int *offsets,
416 Indirect chain[4], int *err)
417{
418 struct super_block *sb = inode->i_sb;
419 Indirect *p = chain;
420 struct buffer_head *bh;
421
422 *err = 0;
423 /* i_data is not going away, no lock needed */
424 add_chain (chain, NULL, EXT3_I(inode)->i_data + *offsets);
425 if (!p->key)
426 goto no_block;
427 while (--depth) {
428 bh = sb_bread(sb, le32_to_cpu(p->key));
429 if (!bh)
430 goto failure;
431 /* Reader: pointers */
432 if (!verify_chain(chain, p))
433 goto changed;
434 add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
435 /* Reader: end */
436 if (!p->key)
437 goto no_block;
438 }
439 return NULL;
440
441changed:
442 brelse(bh);
443 *err = -EAGAIN;
444 goto no_block;
445failure:
446 *err = -EIO;
447no_block:
448 return p;
449}
450
451/**
452 * ext3_find_near - find a place for allocation with sufficient locality
453 * @inode: owner
454 * @ind: descriptor of indirect block.
455 *
456 * This function returns the preferred place for block allocation.
457 * It is used when heuristic for sequential allocation fails.
458 * Rules are:
459 * + if there is a block to the left of our position - allocate near it.
460 * + if pointer will live in indirect block - allocate near that block.
461 * + if pointer will live in inode - allocate in the same
462 * cylinder group.
463 *
464 * In the latter case we colour the starting block by the callers PID to
465 * prevent it from clashing with concurrent allocations for a different inode
466 * in the same block group. The PID is used here so that functionally related
467 * files will be close-by on-disk.
468 *
469 * Caller must make sure that @ind is valid and will stay that way.
470 */
471static ext3_fsblk_t ext3_find_near(struct inode *inode, Indirect *ind)
472{
473 struct ext3_inode_info *ei = EXT3_I(inode);
474 __le32 *start = ind->bh ? (__le32*) ind->bh->b_data : ei->i_data;
475 __le32 *p;
476 ext3_fsblk_t bg_start;
477 ext3_grpblk_t colour;
478
479 /* Try to find previous block */
480 for (p = ind->p - 1; p >= start; p--) {
481 if (*p)
482 return le32_to_cpu(*p);
483 }
484
485 /* No such thing, so let's try location of indirect block */
486 if (ind->bh)
487 return ind->bh->b_blocknr;
488
489 /*
490 * It is going to be referred to from the inode itself? OK, just put it
491 * into the same cylinder group then.
492 */
493 bg_start = ext3_group_first_block_no(inode->i_sb, ei->i_block_group);
494 colour = (current->pid % 16) *
495 (EXT3_BLOCKS_PER_GROUP(inode->i_sb) / 16);
496 return bg_start + colour;
497}
498
499/**
500 * ext3_find_goal - find a preferred place for allocation.
501 * @inode: owner
502 * @block: block we want
503 * @partial: pointer to the last triple within a chain
504 *
505 * Normally this function find the preferred place for block allocation,
506 * returns it.
507 */
508
509static ext3_fsblk_t ext3_find_goal(struct inode *inode, long block,
510 Indirect *partial)
511{
512 struct ext3_block_alloc_info *block_i;
513
514 block_i = EXT3_I(inode)->i_block_alloc_info;
515
516 /*
517 * try the heuristic for sequential allocation,
518 * failing that at least try to get decent locality.
519 */
520 if (block_i && (block == block_i->last_alloc_logical_block + 1)
521 && (block_i->last_alloc_physical_block != 0)) {
522 return block_i->last_alloc_physical_block + 1;
523 }
524
525 return ext3_find_near(inode, partial);
526}
527
528/**
529 * ext3_blks_to_allocate - Look up the block map and count the number
530 * of direct blocks need to be allocated for the given branch.
531 *
532 * @branch: chain of indirect blocks
533 * @k: number of blocks need for indirect blocks
534 * @blks: number of data blocks to be mapped.
535 * @blocks_to_boundary: the offset in the indirect block
536 *
537 * return the total number of blocks to be allocate, including the
538 * direct and indirect blocks.
539 */
540static int ext3_blks_to_allocate(Indirect *branch, int k, unsigned long blks,
541 int blocks_to_boundary)
542{
543 unsigned long count = 0;
544
545 /*
546 * Simple case, [t,d]Indirect block(s) has not allocated yet
547 * then it's clear blocks on that path have not allocated
548 */
549 if (k > 0) {
550 /* right now we don't handle cross boundary allocation */
551 if (blks < blocks_to_boundary + 1)
552 count += blks;
553 else
554 count += blocks_to_boundary + 1;
555 return count;
556 }
557
558 count++;
559 while (count < blks && count <= blocks_to_boundary &&
560 le32_to_cpu(*(branch[0].p + count)) == 0) {
561 count++;
562 }
563 return count;
564}
565
566/**
567 * ext3_alloc_blocks - multiple allocate blocks needed for a branch
568 * @handle: handle for this transaction
569 * @inode: owner
570 * @goal: preferred place for allocation
571 * @indirect_blks: the number of blocks need to allocate for indirect
572 * blocks
573 * @blks: number of blocks need to allocated for direct blocks
574 * @new_blocks: on return it will store the new block numbers for
575 * the indirect blocks(if needed) and the first direct block,
576 * @err: here we store the error value
577 *
578 * return the number of direct blocks allocated
579 */
580static int ext3_alloc_blocks(handle_t *handle, struct inode *inode,
581 ext3_fsblk_t goal, int indirect_blks, int blks,
582 ext3_fsblk_t new_blocks[4], int *err)
583{
584 int target, i;
585 unsigned long count = 0;
586 int index = 0;
587 ext3_fsblk_t current_block = 0;
588 int ret = 0;
589
590 /*
591 * Here we try to allocate the requested multiple blocks at once,
592 * on a best-effort basis.
593 * To build a branch, we should allocate blocks for
594 * the indirect blocks(if not allocated yet), and at least
595 * the first direct block of this branch. That's the
596 * minimum number of blocks need to allocate(required)
597 */
598 target = blks + indirect_blks;
599
600 while (1) {
601 count = target;
602 /* allocating blocks for indirect blocks and direct blocks */
603 current_block = ext3_new_blocks(handle,inode,goal,&count,err);
604 if (*err)
605 goto failed_out;
606
607 target -= count;
608 /* allocate blocks for indirect blocks */
609 while (index < indirect_blks && count) {
610 new_blocks[index++] = current_block++;
611 count--;
612 }
613
614 if (count > 0)
615 break;
616 }
617
618 /* save the new block number for the first direct block */
619 new_blocks[index] = current_block;
620
621 /* total number of blocks allocated for direct blocks */
622 ret = count;
623 *err = 0;
624 return ret;
625failed_out:
626 for (i = 0; i <index; i++)
627 ext3_free_blocks(handle, inode, new_blocks[i], 1);
628 return ret;
629}
630
631/**
632 * ext3_alloc_branch - allocate and set up a chain of blocks.
633 * @handle: handle for this transaction
634 * @inode: owner
635 * @indirect_blks: number of allocated indirect blocks
636 * @blks: number of allocated direct blocks
637 * @goal: preferred place for allocation
638 * @offsets: offsets (in the blocks) to store the pointers to next.
639 * @branch: place to store the chain in.
640 *
641 * This function allocates blocks, zeroes out all but the last one,
642 * links them into chain and (if we are synchronous) writes them to disk.
643 * In other words, it prepares a branch that can be spliced onto the
644 * inode. It stores the information about that chain in the branch[], in
645 * the same format as ext3_get_branch() would do. We are calling it after
646 * we had read the existing part of chain and partial points to the last
647 * triple of that (one with zero ->key). Upon the exit we have the same
648 * picture as after the successful ext3_get_block(), except that in one
649 * place chain is disconnected - *branch->p is still zero (we did not
650 * set the last link), but branch->key contains the number that should
651 * be placed into *branch->p to fill that gap.
652 *
653 * If allocation fails we free all blocks we've allocated (and forget
654 * their buffer_heads) and return the error value the from failed
655 * ext3_alloc_block() (normally -ENOSPC). Otherwise we set the chain
656 * as described above and return 0.
657 */
658static int ext3_alloc_branch(handle_t *handle, struct inode *inode,
659 int indirect_blks, int *blks, ext3_fsblk_t goal,
660 int *offsets, Indirect *branch)
661{
662 int blocksize = inode->i_sb->s_blocksize;
663 int i, n = 0;
664 int err = 0;
665 struct buffer_head *bh;
666 int num;
667 ext3_fsblk_t new_blocks[4];
668 ext3_fsblk_t current_block;
669
670 num = ext3_alloc_blocks(handle, inode, goal, indirect_blks,
671 *blks, new_blocks, &err);
672 if (err)
673 return err;
674
675 branch[0].key = cpu_to_le32(new_blocks[0]);
676 /*
677 * metadata blocks and data blocks are allocated.
678 */
679 for (n = 1; n <= indirect_blks; n++) {
680 /*
681 * Get buffer_head for parent block, zero it out
682 * and set the pointer to new one, then send
683 * parent to disk.
684 */
685 bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
686 branch[n].bh = bh;
687 lock_buffer(bh);
688 BUFFER_TRACE(bh, "call get_create_access");
689 err = ext3_journal_get_create_access(handle, bh);
690 if (err) {
691 unlock_buffer(bh);
692 brelse(bh);
693 goto failed;
694 }
695
696 memset(bh->b_data, 0, blocksize);
697 branch[n].p = (__le32 *) bh->b_data + offsets[n];
698 branch[n].key = cpu_to_le32(new_blocks[n]);
699 *branch[n].p = branch[n].key;
700 if ( n == indirect_blks) {
701 current_block = new_blocks[n];
702 /*
703 * End of chain, update the last new metablock of
704 * the chain to point to the new allocated
705 * data blocks numbers
706 */
707 for (i=1; i < num; i++)
708 *(branch[n].p + i) = cpu_to_le32(++current_block);
709 }
710 BUFFER_TRACE(bh, "marking uptodate");
711 set_buffer_uptodate(bh);
712 unlock_buffer(bh);
713
714 BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
715 err = ext3_journal_dirty_metadata(handle, bh);
716 if (err)
717 goto failed;
718 }
719 *blks = num;
720 return err;
721failed:
722 /* Allocation failed, free what we already allocated */
723 for (i = 1; i <= n ; i++) {
724 BUFFER_TRACE(branch[i].bh, "call journal_forget");
725 ext3_journal_forget(handle, branch[i].bh);
726 }
727 for (i = 0; i <indirect_blks; i++)
728 ext3_free_blocks(handle, inode, new_blocks[i], 1);
729
730 ext3_free_blocks(handle, inode, new_blocks[i], num);
731
732 return err;
733}
734
735/**
736 * ext3_splice_branch - splice the allocated branch onto inode.
737 * @handle: handle for this transaction
738 * @inode: owner
739 * @block: (logical) number of block we are adding
740 * @where: location of missing link
741 * @num: number of indirect blocks we are adding
742 * @blks: number of direct blocks we are adding
743 *
744 * This function fills the missing link and does all housekeeping needed in
745 * inode (->i_blocks, etc.). In case of success we end up with the full
746 * chain to new block and return 0.
747 */
748static int ext3_splice_branch(handle_t *handle, struct inode *inode,
749 long block, Indirect *where, int num, int blks)
750{
751 int i;
752 int err = 0;
753 struct ext3_block_alloc_info *block_i;
754 ext3_fsblk_t current_block;
755 struct ext3_inode_info *ei = EXT3_I(inode);
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
796 inode->i_ctime = CURRENT_TIME_SEC;
797 ext3_mark_inode_dirty(handle, inode);
798 /* ext3_mark_inode_dirty already updated i_sync_tid */
799 atomic_set(&ei->i_datasync_tid, handle->h_transaction->t_tid);
800
801 /* had we spliced it onto indirect block? */
802 if (where->bh) {
803 /*
804 * If we spliced it onto an indirect block, we haven't
805 * altered the inode. Note however that if it is being spliced
806 * onto an indirect block at the very end of the file (the
807 * file is growing) then we *will* alter the inode to reflect
808 * the new i_size. But that is not done here - it is done in
809 * generic_commit_write->__mark_inode_dirty->ext3_dirty_inode.
810 */
811 jbd_debug(5, "splicing indirect only\n");
812 BUFFER_TRACE(where->bh, "call ext3_journal_dirty_metadata");
813 err = ext3_journal_dirty_metadata(handle, where->bh);
814 if (err)
815 goto err_out;
816 } else {
817 /*
818 * OK, we spliced it into the inode itself on a direct block.
819 * Inode was dirtied above.
820 */
821 jbd_debug(5, "splicing direct\n");
822 }
823 return err;
824
825err_out:
826 for (i = 1; i <= num; i++) {
827 BUFFER_TRACE(where[i].bh, "call journal_forget");
828 ext3_journal_forget(handle, where[i].bh);
829 ext3_free_blocks(handle,inode,le32_to_cpu(where[i-1].key),1);
830 }
831 ext3_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks);
832
833 return err;
834}
835
836/*
837 * Allocation strategy is simple: if we have to allocate something, we will
838 * have to go the whole way to leaf. So let's do it before attaching anything
839 * to tree, set linkage between the newborn blocks, write them if sync is
840 * required, recheck the path, free and repeat if check fails, otherwise
841 * set the last missing link (that will protect us from any truncate-generated
842 * removals - all blocks on the path are immune now) and possibly force the
843 * write on the parent block.
844 * That has a nice additional property: no special recovery from the failed
845 * allocations is needed - we simply release blocks and do not touch anything
846 * reachable from inode.
847 *
848 * `handle' can be NULL if create == 0.
849 *
850 * The BKL may not be held on entry here. Be sure to take it early.
851 * return > 0, # of blocks mapped or allocated.
852 * return = 0, if plain lookup failed.
853 * return < 0, error case.
854 */
855int ext3_get_blocks_handle(handle_t *handle, struct inode *inode,
856 sector_t iblock, unsigned long maxblocks,
857 struct buffer_head *bh_result,
858 int create)
859{
860 int err = -EIO;
861 int offsets[4];
862 Indirect chain[4];
863 Indirect *partial;
864 ext3_fsblk_t goal;
865 int indirect_blks;
866 int blocks_to_boundary = 0;
867 int depth;
868 struct ext3_inode_info *ei = EXT3_I(inode);
869 int count = 0;
870 ext3_fsblk_t first_block = 0;
871
872
873 trace_ext3_get_blocks_enter(inode, iblock, maxblocks, create);
874 J_ASSERT(handle != NULL || create == 0);
875 depth = ext3_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
876
877 if (depth == 0)
878 goto out;
879
880 partial = ext3_get_branch(inode, depth, offsets, chain, &err);
881
882 /* Simplest case - block found, no allocation needed */
883 if (!partial) {
884 first_block = le32_to_cpu(chain[depth - 1].key);
885 clear_buffer_new(bh_result);
886 count++;
887 /*map more blocks*/
888 while (count < maxblocks && count <= blocks_to_boundary) {
889 ext3_fsblk_t blk;
890
891 if (!verify_chain(chain, chain + depth - 1)) {
892 /*
893 * Indirect block might be removed by
894 * truncate while we were reading it.
895 * Handling of that case: forget what we've
896 * got now. Flag the err as EAGAIN, so it
897 * will reread.
898 */
899 err = -EAGAIN;
900 count = 0;
901 break;
902 }
903 blk = le32_to_cpu(*(chain[depth-1].p + count));
904
905 if (blk == first_block + count)
906 count++;
907 else
908 break;
909 }
910 if (err != -EAGAIN)
911 goto got_it;
912 }
913
914 /* Next simple case - plain lookup or failed read of indirect block */
915 if (!create || err == -EIO)
916 goto cleanup;
917
918 /*
919 * Block out ext3_truncate while we alter the tree
920 */
921 mutex_lock(&ei->truncate_mutex);
922
923 /*
924 * If the indirect block is missing while we are reading
925 * the chain(ext3_get_branch() returns -EAGAIN err), or
926 * if the chain has been changed after we grab the semaphore,
927 * (either because another process truncated this branch, or
928 * another get_block allocated this branch) re-grab the chain to see if
929 * the request block has been allocated or not.
930 *
931 * Since we already block the truncate/other get_block
932 * at this point, we will have the current copy of the chain when we
933 * splice the branch into the tree.
934 */
935 if (err == -EAGAIN || !verify_chain(chain, partial)) {
936 while (partial > chain) {
937 brelse(partial->bh);
938 partial--;
939 }
940 partial = ext3_get_branch(inode, depth, offsets, chain, &err);
941 if (!partial) {
942 count++;
943 mutex_unlock(&ei->truncate_mutex);
944 if (err)
945 goto cleanup;
946 clear_buffer_new(bh_result);
947 goto got_it;
948 }
949 }
950
951 /*
952 * Okay, we need to do block allocation. Lazily initialize the block
953 * allocation info here if necessary
954 */
955 if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
956 ext3_init_block_alloc_info(inode);
957
958 goal = ext3_find_goal(inode, iblock, partial);
959
960 /* the number of blocks need to allocate for [d,t]indirect blocks */
961 indirect_blks = (chain + depth) - partial - 1;
962
963 /*
964 * Next look up the indirect map to count the totoal number of
965 * direct blocks to allocate for this branch.
966 */
967 count = ext3_blks_to_allocate(partial, indirect_blks,
968 maxblocks, blocks_to_boundary);
969 err = ext3_alloc_branch(handle, inode, indirect_blks, &count, goal,
970 offsets + (partial - chain), partial);
971
972 /*
973 * The ext3_splice_branch call will free and forget any buffers
974 * on the new chain if there is a failure, but that risks using
975 * up transaction credits, especially for bitmaps where the
976 * credits cannot be returned. Can we handle this somehow? We
977 * may need to return -EAGAIN upwards in the worst case. --sct
978 */
979 if (!err)
980 err = ext3_splice_branch(handle, inode, iblock,
981 partial, indirect_blks, count);
982 mutex_unlock(&ei->truncate_mutex);
983 if (err)
984 goto cleanup;
985
986 set_buffer_new(bh_result);
987got_it:
988 map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
989 if (count > blocks_to_boundary)
990 set_buffer_boundary(bh_result);
991 err = count;
992 /* Clean up and exit */
993 partial = chain + depth - 1; /* the whole chain */
994cleanup:
995 while (partial > chain) {
996 BUFFER_TRACE(partial->bh, "call brelse");
997 brelse(partial->bh);
998 partial--;
999 }
1000 BUFFER_TRACE(bh_result, "returned");
1001out:
1002 trace_ext3_get_blocks_exit(inode, iblock,
1003 depth ? le32_to_cpu(chain[depth-1].key) : 0,
1004 count, err);
1005 return err;
1006}
1007
1008/* Maximum number of blocks we map for direct IO at once. */
1009#define DIO_MAX_BLOCKS 4096
1010/*
1011 * Number of credits we need for writing DIO_MAX_BLOCKS:
1012 * We need sb + group descriptor + bitmap + inode -> 4
1013 * For B blocks with A block pointers per block we need:
1014 * 1 (triple ind.) + (B/A/A + 2) (doubly ind.) + (B/A + 2) (indirect).
1015 * If we plug in 4096 for B and 256 for A (for 1KB block size), we get 25.
1016 */
1017#define DIO_CREDITS 25
1018
1019static int ext3_get_block(struct inode *inode, sector_t iblock,
1020 struct buffer_head *bh_result, int create)
1021{
1022 handle_t *handle = ext3_journal_current_handle();
1023 int ret = 0, started = 0;
1024 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
1025
1026 if (create && !handle) { /* Direct IO write... */
1027 if (max_blocks > DIO_MAX_BLOCKS)
1028 max_blocks = DIO_MAX_BLOCKS;
1029 handle = ext3_journal_start(inode, DIO_CREDITS +
1030 EXT3_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb));
1031 if (IS_ERR(handle)) {
1032 ret = PTR_ERR(handle);
1033 goto out;
1034 }
1035 started = 1;
1036 }
1037
1038 ret = ext3_get_blocks_handle(handle, inode, iblock,
1039 max_blocks, bh_result, create);
1040 if (ret > 0) {
1041 bh_result->b_size = (ret << inode->i_blkbits);
1042 ret = 0;
1043 }
1044 if (started)
1045 ext3_journal_stop(handle);
1046out:
1047 return ret;
1048}
1049
1050int ext3_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
1051 u64 start, u64 len)
1052{
1053 return generic_block_fiemap(inode, fieinfo, start, len,
1054 ext3_get_block);
1055}
1056
1057/*
1058 * `handle' can be NULL if create is zero
1059 */
1060struct buffer_head *ext3_getblk(handle_t *handle, struct inode *inode,
1061 long block, int create, int *errp)
1062{
1063 struct buffer_head dummy;
1064 int fatal = 0, err;
1065
1066 J_ASSERT(handle != NULL || create == 0);
1067
1068 dummy.b_state = 0;
1069 dummy.b_blocknr = -1000;
1070 buffer_trace_init(&dummy.b_history);
1071 err = ext3_get_blocks_handle(handle, inode, block, 1,
1072 &dummy, create);
1073 /*
1074 * ext3_get_blocks_handle() returns number of blocks
1075 * mapped. 0 in case of a HOLE.
1076 */
1077 if (err > 0) {
1078 if (err > 1)
1079 WARN_ON(1);
1080 err = 0;
1081 }
1082 *errp = err;
1083 if (!err && buffer_mapped(&dummy)) {
1084 struct buffer_head *bh;
1085 bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
1086 if (!bh) {
1087 *errp = -EIO;
1088 goto err;
1089 }
1090 if (buffer_new(&dummy)) {
1091 J_ASSERT(create != 0);
1092 J_ASSERT(handle != NULL);
1093
1094 /*
1095 * Now that we do not always journal data, we should
1096 * keep in mind whether this should always journal the
1097 * new buffer as metadata. For now, regular file
1098 * writes use ext3_get_block instead, so it's not a
1099 * problem.
1100 */
1101 lock_buffer(bh);
1102 BUFFER_TRACE(bh, "call get_create_access");
1103 fatal = ext3_journal_get_create_access(handle, bh);
1104 if (!fatal && !buffer_uptodate(bh)) {
1105 memset(bh->b_data,0,inode->i_sb->s_blocksize);
1106 set_buffer_uptodate(bh);
1107 }
1108 unlock_buffer(bh);
1109 BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
1110 err = ext3_journal_dirty_metadata(handle, bh);
1111 if (!fatal)
1112 fatal = err;
1113 } else {
1114 BUFFER_TRACE(bh, "not a new buffer");
1115 }
1116 if (fatal) {
1117 *errp = fatal;
1118 brelse(bh);
1119 bh = NULL;
1120 }
1121 return bh;
1122 }
1123err:
1124 return NULL;
1125}
1126
1127struct buffer_head *ext3_bread(handle_t *handle, struct inode *inode,
1128 int block, int create, int *err)
1129{
1130 struct buffer_head * bh;
1131
1132 bh = ext3_getblk(handle, inode, block, create, err);
1133 if (!bh)
1134 return bh;
1135 if (buffer_uptodate(bh))
1136 return bh;
1137 ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh);
1138 wait_on_buffer(bh);
1139 if (buffer_uptodate(bh))
1140 return bh;
1141 put_bh(bh);
1142 *err = -EIO;
1143 return NULL;
1144}
1145
1146static int walk_page_buffers( handle_t *handle,
1147 struct buffer_head *head,
1148 unsigned from,
1149 unsigned to,
1150 int *partial,
1151 int (*fn)( handle_t *handle,
1152 struct buffer_head *bh))
1153{
1154 struct buffer_head *bh;
1155 unsigned block_start, block_end;
1156 unsigned blocksize = head->b_size;
1157 int err, ret = 0;
1158 struct buffer_head *next;
1159
1160 for ( bh = head, block_start = 0;
1161 ret == 0 && (bh != head || !block_start);
1162 block_start = block_end, bh = next)
1163 {
1164 next = bh->b_this_page;
1165 block_end = block_start + blocksize;
1166 if (block_end <= from || block_start >= to) {
1167 if (partial && !buffer_uptodate(bh))
1168 *partial = 1;
1169 continue;
1170 }
1171 err = (*fn)(handle, bh);
1172 if (!ret)
1173 ret = err;
1174 }
1175 return ret;
1176}
1177
1178/*
1179 * To preserve ordering, it is essential that the hole instantiation and
1180 * the data write be encapsulated in a single transaction. We cannot
1181 * close off a transaction and start a new one between the ext3_get_block()
1182 * and the commit_write(). So doing the journal_start at the start of
1183 * prepare_write() is the right place.
1184 *
1185 * Also, this function can nest inside ext3_writepage() ->
1186 * block_write_full_page(). In that case, we *know* that ext3_writepage()
1187 * has generated enough buffer credits to do the whole page. So we won't
1188 * block on the journal in that case, which is good, because the caller may
1189 * be PF_MEMALLOC.
1190 *
1191 * By accident, ext3 can be reentered when a transaction is open via
1192 * quota file writes. If we were to commit the transaction while thus
1193 * reentered, there can be a deadlock - we would be holding a quota
1194 * lock, and the commit would never complete if another thread had a
1195 * transaction open and was blocking on the quota lock - a ranking
1196 * violation.
1197 *
1198 * So what we do is to rely on the fact that journal_stop/journal_start
1199 * will _not_ run commit under these circumstances because handle->h_ref
1200 * is elevated. We'll still have enough credits for the tiny quotafile
1201 * write.
1202 */
1203static int do_journal_get_write_access(handle_t *handle,
1204 struct buffer_head *bh)
1205{
1206 int dirty = buffer_dirty(bh);
1207 int ret;
1208
1209 if (!buffer_mapped(bh) || buffer_freed(bh))
1210 return 0;
1211 /*
1212 * __block_prepare_write() could have dirtied some buffers. Clean
1213 * the dirty bit as jbd2_journal_get_write_access() could complain
1214 * otherwise about fs integrity issues. Setting of the dirty bit
1215 * by __block_prepare_write() isn't a real problem here as we clear
1216 * the bit before releasing a page lock and thus writeback cannot
1217 * ever write the buffer.
1218 */
1219 if (dirty)
1220 clear_buffer_dirty(bh);
1221 ret = ext3_journal_get_write_access(handle, bh);
1222 if (!ret && dirty)
1223 ret = ext3_journal_dirty_metadata(handle, bh);
1224 return ret;
1225}
1226
1227/*
1228 * Truncate blocks that were not used by write. We have to truncate the
1229 * pagecache as well so that corresponding buffers get properly unmapped.
1230 */
1231static void ext3_truncate_failed_write(struct inode *inode)
1232{
1233 truncate_inode_pages(inode->i_mapping, inode->i_size);
1234 ext3_truncate(inode);
1235}
1236
1237/*
1238 * Truncate blocks that were not used by direct IO write. We have to zero out
1239 * the last file block as well because direct IO might have written to it.
1240 */
1241static void ext3_truncate_failed_direct_write(struct inode *inode)
1242{
1243 ext3_block_truncate_page(inode, inode->i_size);
1244 ext3_truncate(inode);
1245}
1246
1247static int ext3_write_begin(struct file *file, struct address_space *mapping,
1248 loff_t pos, unsigned len, unsigned flags,
1249 struct page **pagep, void **fsdata)
1250{
1251 struct inode *inode = mapping->host;
1252 int ret;
1253 handle_t *handle;
1254 int retries = 0;
1255 struct page *page;
1256 pgoff_t index;
1257 unsigned from, to;
1258 /* Reserve one block more for addition to orphan list in case
1259 * we allocate blocks but write fails for some reason */
1260 int needed_blocks = ext3_writepage_trans_blocks(inode) + 1;
1261
1262 trace_ext3_write_begin(inode, pos, len, flags);
1263
1264 index = pos >> PAGE_CACHE_SHIFT;
1265 from = pos & (PAGE_CACHE_SIZE - 1);
1266 to = from + len;
1267
1268retry:
1269 page = grab_cache_page_write_begin(mapping, index, flags);
1270 if (!page)
1271 return -ENOMEM;
1272 *pagep = page;
1273
1274 handle = ext3_journal_start(inode, needed_blocks);
1275 if (IS_ERR(handle)) {
1276 unlock_page(page);
1277 page_cache_release(page);
1278 ret = PTR_ERR(handle);
1279 goto out;
1280 }
1281 ret = __block_write_begin(page, pos, len, ext3_get_block);
1282 if (ret)
1283 goto write_begin_failed;
1284
1285 if (ext3_should_journal_data(inode)) {
1286 ret = walk_page_buffers(handle, page_buffers(page),
1287 from, to, NULL, do_journal_get_write_access);
1288 }
1289write_begin_failed:
1290 if (ret) {
1291 /*
1292 * block_write_begin may have instantiated a few blocks
1293 * outside i_size. Trim these off again. Don't need
1294 * i_size_read because we hold i_mutex.
1295 *
1296 * Add inode to orphan list in case we crash before truncate
1297 * finishes. Do this only if ext3_can_truncate() agrees so
1298 * that orphan processing code is happy.
1299 */
1300 if (pos + len > inode->i_size && ext3_can_truncate(inode))
1301 ext3_orphan_add(handle, inode);
1302 ext3_journal_stop(handle);
1303 unlock_page(page);
1304 page_cache_release(page);
1305 if (pos + len > inode->i_size)
1306 ext3_truncate_failed_write(inode);
1307 }
1308 if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
1309 goto retry;
1310out:
1311 return ret;
1312}
1313
1314
1315int ext3_journal_dirty_data(handle_t *handle, struct buffer_head *bh)
1316{
1317 int err = journal_dirty_data(handle, bh);
1318 if (err)
1319 ext3_journal_abort_handle(__func__, __func__,
1320 bh, handle, err);
1321 return err;
1322}
1323
1324/* For ordered writepage and write_end functions */
1325static int journal_dirty_data_fn(handle_t *handle, struct buffer_head *bh)
1326{
1327 /*
1328 * Write could have mapped the buffer but it didn't copy the data in
1329 * yet. So avoid filing such buffer into a transaction.
1330 */
1331 if (buffer_mapped(bh) && buffer_uptodate(bh))
1332 return ext3_journal_dirty_data(handle, bh);
1333 return 0;
1334}
1335
1336/* For write_end() in data=journal mode */
1337static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1338{
1339 if (!buffer_mapped(bh) || buffer_freed(bh))
1340 return 0;
1341 set_buffer_uptodate(bh);
1342 return ext3_journal_dirty_metadata(handle, bh);
1343}
1344
1345/*
1346 * This is nasty and subtle: ext3_write_begin() could have allocated blocks
1347 * for the whole page but later we failed to copy the data in. Update inode
1348 * size according to what we managed to copy. The rest is going to be
1349 * truncated in write_end function.
1350 */
1351static void update_file_sizes(struct inode *inode, loff_t pos, unsigned copied)
1352{
1353 /* What matters to us is i_disksize. We don't write i_size anywhere */
1354 if (pos + copied > inode->i_size)
1355 i_size_write(inode, pos + copied);
1356 if (pos + copied > EXT3_I(inode)->i_disksize) {
1357 EXT3_I(inode)->i_disksize = pos + copied;
1358 mark_inode_dirty(inode);
1359 }
1360}
1361
1362/*
1363 * We need to pick up the new inode size which generic_commit_write gave us
1364 * `file' can be NULL - eg, when called from page_symlink().
1365 *
1366 * ext3 never places buffers on inode->i_mapping->private_list. metadata
1367 * buffers are managed internally.
1368 */
1369static int ext3_ordered_write_end(struct file *file,
1370 struct address_space *mapping,
1371 loff_t pos, unsigned len, unsigned copied,
1372 struct page *page, void *fsdata)
1373{
1374 handle_t *handle = ext3_journal_current_handle();
1375 struct inode *inode = file->f_mapping->host;
1376 unsigned from, to;
1377 int ret = 0, ret2;
1378
1379 trace_ext3_ordered_write_end(inode, pos, len, copied);
1380 copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
1381
1382 from = pos & (PAGE_CACHE_SIZE - 1);
1383 to = from + copied;
1384 ret = walk_page_buffers(handle, page_buffers(page),
1385 from, to, NULL, journal_dirty_data_fn);
1386
1387 if (ret == 0)
1388 update_file_sizes(inode, pos, copied);
1389 /*
1390 * There may be allocated blocks outside of i_size because
1391 * we failed to copy some data. Prepare for truncate.
1392 */
1393 if (pos + len > inode->i_size && ext3_can_truncate(inode))
1394 ext3_orphan_add(handle, inode);
1395 ret2 = ext3_journal_stop(handle);
1396 if (!ret)
1397 ret = ret2;
1398 unlock_page(page);
1399 page_cache_release(page);
1400
1401 if (pos + len > inode->i_size)
1402 ext3_truncate_failed_write(inode);
1403 return ret ? ret : copied;
1404}
1405
1406static int ext3_writeback_write_end(struct file *file,
1407 struct address_space *mapping,
1408 loff_t pos, unsigned len, unsigned copied,
1409 struct page *page, void *fsdata)
1410{
1411 handle_t *handle = ext3_journal_current_handle();
1412 struct inode *inode = file->f_mapping->host;
1413 int ret;
1414
1415 trace_ext3_writeback_write_end(inode, pos, len, copied);
1416 copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
1417 update_file_sizes(inode, pos, copied);
1418 /*
1419 * There may be allocated blocks outside of i_size because
1420 * we failed to copy some data. Prepare for truncate.
1421 */
1422 if (pos + len > inode->i_size && ext3_can_truncate(inode))
1423 ext3_orphan_add(handle, inode);
1424 ret = ext3_journal_stop(handle);
1425 unlock_page(page);
1426 page_cache_release(page);
1427
1428 if (pos + len > inode->i_size)
1429 ext3_truncate_failed_write(inode);
1430 return ret ? ret : copied;
1431}
1432
1433static int ext3_journalled_write_end(struct file *file,
1434 struct address_space *mapping,
1435 loff_t pos, unsigned len, unsigned copied,
1436 struct page *page, void *fsdata)
1437{
1438 handle_t *handle = ext3_journal_current_handle();
1439 struct inode *inode = mapping->host;
1440 struct ext3_inode_info *ei = EXT3_I(inode);
1441 int ret = 0, ret2;
1442 int partial = 0;
1443 unsigned from, to;
1444
1445 trace_ext3_journalled_write_end(inode, pos, len, copied);
1446 from = pos & (PAGE_CACHE_SIZE - 1);
1447 to = from + len;
1448
1449 if (copied < len) {
1450 if (!PageUptodate(page))
1451 copied = 0;
1452 page_zero_new_buffers(page, from + copied, to);
1453 to = from + copied;
1454 }
1455
1456 ret = walk_page_buffers(handle, page_buffers(page), from,
1457 to, &partial, write_end_fn);
1458 if (!partial)
1459 SetPageUptodate(page);
1460
1461 if (pos + copied > inode->i_size)
1462 i_size_write(inode, pos + copied);
1463 /*
1464 * There may be allocated blocks outside of i_size because
1465 * we failed to copy some data. Prepare for truncate.
1466 */
1467 if (pos + len > inode->i_size && ext3_can_truncate(inode))
1468 ext3_orphan_add(handle, inode);
1469 ext3_set_inode_state(inode, EXT3_STATE_JDATA);
1470 atomic_set(&ei->i_datasync_tid, handle->h_transaction->t_tid);
1471 if (inode->i_size > ei->i_disksize) {
1472 ei->i_disksize = inode->i_size;
1473 ret2 = ext3_mark_inode_dirty(handle, inode);
1474 if (!ret)
1475 ret = ret2;
1476 }
1477
1478 ret2 = ext3_journal_stop(handle);
1479 if (!ret)
1480 ret = ret2;
1481 unlock_page(page);
1482 page_cache_release(page);
1483
1484 if (pos + len > inode->i_size)
1485 ext3_truncate_failed_write(inode);
1486 return ret ? ret : copied;
1487}
1488
1489/*
1490 * bmap() is special. It gets used by applications such as lilo and by
1491 * the swapper to find the on-disk block of a specific piece of data.
1492 *
1493 * Naturally, this is dangerous if the block concerned is still in the
1494 * journal. If somebody makes a swapfile on an ext3 data-journaling
1495 * filesystem and enables swap, then they may get a nasty shock when the
1496 * data getting swapped to that swapfile suddenly gets overwritten by
1497 * the original zero's written out previously to the journal and
1498 * awaiting writeback in the kernel's buffer cache.
1499 *
1500 * So, if we see any bmap calls here on a modified, data-journaled file,
1501 * take extra steps to flush any blocks which might be in the cache.
1502 */
1503static sector_t ext3_bmap(struct address_space *mapping, sector_t block)
1504{
1505 struct inode *inode = mapping->host;
1506 journal_t *journal;
1507 int err;
1508
1509 if (ext3_test_inode_state(inode, EXT3_STATE_JDATA)) {
1510 /*
1511 * This is a REALLY heavyweight approach, but the use of
1512 * bmap on dirty files is expected to be extremely rare:
1513 * only if we run lilo or swapon on a freshly made file
1514 * do we expect this to happen.
1515 *
1516 * (bmap requires CAP_SYS_RAWIO so this does not
1517 * represent an unprivileged user DOS attack --- we'd be
1518 * in trouble if mortal users could trigger this path at
1519 * will.)
1520 *
1521 * NB. EXT3_STATE_JDATA is not set on files other than
1522 * regular files. If somebody wants to bmap a directory
1523 * or symlink and gets confused because the buffer
1524 * hasn't yet been flushed to disk, they deserve
1525 * everything they get.
1526 */
1527
1528 ext3_clear_inode_state(inode, EXT3_STATE_JDATA);
1529 journal = EXT3_JOURNAL(inode);
1530 journal_lock_updates(journal);
1531 err = journal_flush(journal);
1532 journal_unlock_updates(journal);
1533
1534 if (err)
1535 return 0;
1536 }
1537
1538 return generic_block_bmap(mapping,block,ext3_get_block);
1539}
1540
1541static int bget_one(handle_t *handle, struct buffer_head *bh)
1542{
1543 get_bh(bh);
1544 return 0;
1545}
1546
1547static int bput_one(handle_t *handle, struct buffer_head *bh)
1548{
1549 put_bh(bh);
1550 return 0;
1551}
1552
1553static int buffer_unmapped(handle_t *handle, struct buffer_head *bh)
1554{
1555 return !buffer_mapped(bh);
1556}
1557
1558/*
1559 * Note that we always start a transaction even if we're not journalling
1560 * data. This is to preserve ordering: any hole instantiation within
1561 * __block_write_full_page -> ext3_get_block() should be journalled
1562 * along with the data so we don't crash and then get metadata which
1563 * refers to old data.
1564 *
1565 * In all journalling modes block_write_full_page() will start the I/O.
1566 *
1567 * Problem:
1568 *
1569 * ext3_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
1570 * ext3_writepage()
1571 *
1572 * Similar for:
1573 *
1574 * ext3_file_write() -> generic_file_write() -> __alloc_pages() -> ...
1575 *
1576 * Same applies to ext3_get_block(). We will deadlock on various things like
1577 * lock_journal and i_truncate_mutex.
1578 *
1579 * Setting PF_MEMALLOC here doesn't work - too many internal memory
1580 * allocations fail.
1581 *
1582 * 16May01: If we're reentered then journal_current_handle() will be
1583 * non-zero. We simply *return*.
1584 *
1585 * 1 July 2001: @@@ FIXME:
1586 * In journalled data mode, a data buffer may be metadata against the
1587 * current transaction. But the same file is part of a shared mapping
1588 * and someone does a writepage() on it.
1589 *
1590 * We will move the buffer onto the async_data list, but *after* it has
1591 * been dirtied. So there's a small window where we have dirty data on
1592 * BJ_Metadata.
1593 *
1594 * Note that this only applies to the last partial page in the file. The
1595 * bit which block_write_full_page() uses prepare/commit for. (That's
1596 * broken code anyway: it's wrong for msync()).
1597 *
1598 * It's a rare case: affects the final partial page, for journalled data
1599 * where the file is subject to bith write() and writepage() in the same
1600 * transction. To fix it we'll need a custom block_write_full_page().
1601 * We'll probably need that anyway for journalling writepage() output.
1602 *
1603 * We don't honour synchronous mounts for writepage(). That would be
1604 * disastrous. Any write() or metadata operation will sync the fs for
1605 * us.
1606 *
1607 * AKPM2: if all the page's buffers are mapped to disk and !data=journal,
1608 * we don't need to open a transaction here.
1609 */
1610static int ext3_ordered_writepage(struct page *page,
1611 struct writeback_control *wbc)
1612{
1613 struct inode *inode = page->mapping->host;
1614 struct buffer_head *page_bufs;
1615 handle_t *handle = NULL;
1616 int ret = 0;
1617 int err;
1618
1619 J_ASSERT(PageLocked(page));
1620 WARN_ON_ONCE(IS_RDONLY(inode));
1621
1622 /*
1623 * We give up here if we're reentered, because it might be for a
1624 * different filesystem.
1625 */
1626 if (ext3_journal_current_handle())
1627 goto out_fail;
1628
1629 trace_ext3_ordered_writepage(page);
1630 if (!page_has_buffers(page)) {
1631 create_empty_buffers(page, inode->i_sb->s_blocksize,
1632 (1 << BH_Dirty)|(1 << BH_Uptodate));
1633 page_bufs = page_buffers(page);
1634 } else {
1635 page_bufs = page_buffers(page);
1636 if (!walk_page_buffers(NULL, page_bufs, 0, PAGE_CACHE_SIZE,
1637 NULL, buffer_unmapped)) {
1638 /* Provide NULL get_block() to catch bugs if buffers
1639 * weren't really mapped */
1640 return block_write_full_page(page, NULL, wbc);
1641 }
1642 }
1643 handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
1644
1645 if (IS_ERR(handle)) {
1646 ret = PTR_ERR(handle);
1647 goto out_fail;
1648 }
1649
1650 walk_page_buffers(handle, page_bufs, 0,
1651 PAGE_CACHE_SIZE, NULL, bget_one);
1652
1653 ret = block_write_full_page(page, ext3_get_block, wbc);
1654
1655 /*
1656 * The page can become unlocked at any point now, and
1657 * truncate can then come in and change things. So we
1658 * can't touch *page from now on. But *page_bufs is
1659 * safe due to elevated refcount.
1660 */
1661
1662 /*
1663 * And attach them to the current transaction. But only if
1664 * block_write_full_page() succeeded. Otherwise they are unmapped,
1665 * and generally junk.
1666 */
1667 if (ret == 0) {
1668 err = walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE,
1669 NULL, journal_dirty_data_fn);
1670 if (!ret)
1671 ret = err;
1672 }
1673 walk_page_buffers(handle, page_bufs, 0,
1674 PAGE_CACHE_SIZE, NULL, bput_one);
1675 err = ext3_journal_stop(handle);
1676 if (!ret)
1677 ret = err;
1678 return ret;
1679
1680out_fail:
1681 redirty_page_for_writepage(wbc, page);
1682 unlock_page(page);
1683 return ret;
1684}
1685
1686static int ext3_writeback_writepage(struct page *page,
1687 struct writeback_control *wbc)
1688{
1689 struct inode *inode = page->mapping->host;
1690 handle_t *handle = NULL;
1691 int ret = 0;
1692 int err;
1693
1694 J_ASSERT(PageLocked(page));
1695 WARN_ON_ONCE(IS_RDONLY(inode));
1696
1697 if (ext3_journal_current_handle())
1698 goto out_fail;
1699
1700 trace_ext3_writeback_writepage(page);
1701 if (page_has_buffers(page)) {
1702 if (!walk_page_buffers(NULL, page_buffers(page), 0,
1703 PAGE_CACHE_SIZE, NULL, buffer_unmapped)) {
1704 /* Provide NULL get_block() to catch bugs if buffers
1705 * weren't really mapped */
1706 return block_write_full_page(page, NULL, wbc);
1707 }
1708 }
1709
1710 handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
1711 if (IS_ERR(handle)) {
1712 ret = PTR_ERR(handle);
1713 goto out_fail;
1714 }
1715
1716 ret = block_write_full_page(page, ext3_get_block, wbc);
1717
1718 err = ext3_journal_stop(handle);
1719 if (!ret)
1720 ret = err;
1721 return ret;
1722
1723out_fail:
1724 redirty_page_for_writepage(wbc, page);
1725 unlock_page(page);
1726 return ret;
1727}
1728
1729static int ext3_journalled_writepage(struct page *page,
1730 struct writeback_control *wbc)
1731{
1732 struct inode *inode = page->mapping->host;
1733 handle_t *handle = NULL;
1734 int ret = 0;
1735 int err;
1736
1737 J_ASSERT(PageLocked(page));
1738 WARN_ON_ONCE(IS_RDONLY(inode));
1739
1740 if (ext3_journal_current_handle())
1741 goto no_write;
1742
1743 trace_ext3_journalled_writepage(page);
1744 handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
1745 if (IS_ERR(handle)) {
1746 ret = PTR_ERR(handle);
1747 goto no_write;
1748 }
1749
1750 if (!page_has_buffers(page) || PageChecked(page)) {
1751 /*
1752 * It's mmapped pagecache. Add buffers and journal it. There
1753 * doesn't seem much point in redirtying the page here.
1754 */
1755 ClearPageChecked(page);
1756 ret = __block_write_begin(page, 0, PAGE_CACHE_SIZE,
1757 ext3_get_block);
1758 if (ret != 0) {
1759 ext3_journal_stop(handle);
1760 goto out_unlock;
1761 }
1762 ret = walk_page_buffers(handle, page_buffers(page), 0,
1763 PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
1764
1765 err = walk_page_buffers(handle, page_buffers(page), 0,
1766 PAGE_CACHE_SIZE, NULL, write_end_fn);
1767 if (ret == 0)
1768 ret = err;
1769 ext3_set_inode_state(inode, EXT3_STATE_JDATA);
1770 atomic_set(&EXT3_I(inode)->i_datasync_tid,
1771 handle->h_transaction->t_tid);
1772 unlock_page(page);
1773 } else {
1774 /*
1775 * It may be a page full of checkpoint-mode buffers. We don't
1776 * really know unless we go poke around in the buffer_heads.
1777 * But block_write_full_page will do the right thing.
1778 */
1779 ret = block_write_full_page(page, ext3_get_block, wbc);
1780 }
1781 err = ext3_journal_stop(handle);
1782 if (!ret)
1783 ret = err;
1784out:
1785 return ret;
1786
1787no_write:
1788 redirty_page_for_writepage(wbc, page);
1789out_unlock:
1790 unlock_page(page);
1791 goto out;
1792}
1793
1794static int ext3_readpage(struct file *file, struct page *page)
1795{
1796 trace_ext3_readpage(page);
1797 return mpage_readpage(page, ext3_get_block);
1798}
1799
1800static int
1801ext3_readpages(struct file *file, struct address_space *mapping,
1802 struct list_head *pages, unsigned nr_pages)
1803{
1804 return mpage_readpages(mapping, pages, nr_pages, ext3_get_block);
1805}
1806
1807static void ext3_invalidatepage(struct page *page, unsigned long offset)
1808{
1809 journal_t *journal = EXT3_JOURNAL(page->mapping->host);
1810
1811 trace_ext3_invalidatepage(page, offset);
1812
1813 /*
1814 * If it's a full truncate we just forget about the pending dirtying
1815 */
1816 if (offset == 0)
1817 ClearPageChecked(page);
1818
1819 journal_invalidatepage(journal, page, offset);
1820}
1821
1822static int ext3_releasepage(struct page *page, gfp_t wait)
1823{
1824 journal_t *journal = EXT3_JOURNAL(page->mapping->host);
1825
1826 trace_ext3_releasepage(page);
1827 WARN_ON(PageChecked(page));
1828 if (!page_has_buffers(page))
1829 return 0;
1830 return journal_try_to_free_buffers(journal, page, wait);
1831}
1832
1833/*
1834 * If the O_DIRECT write will extend the file then add this inode to the
1835 * orphan list. So recovery will truncate it back to the original size
1836 * if the machine crashes during the write.
1837 *
1838 * If the O_DIRECT write is intantiating holes inside i_size and the machine
1839 * crashes then stale disk data _may_ be exposed inside the file. But current
1840 * VFS code falls back into buffered path in that case so we are safe.
1841 */
1842static ssize_t ext3_direct_IO(int rw, struct kiocb *iocb,
1843 const struct iovec *iov, loff_t offset,
1844 unsigned long nr_segs)
1845{
1846 struct file *file = iocb->ki_filp;
1847 struct inode *inode = file->f_mapping->host;
1848 struct ext3_inode_info *ei = EXT3_I(inode);
1849 handle_t *handle;
1850 ssize_t ret;
1851 int orphan = 0;
1852 size_t count = iov_length(iov, nr_segs);
1853 int retries = 0;
1854
1855 trace_ext3_direct_IO_enter(inode, offset, iov_length(iov, nr_segs), rw);
1856
1857 if (rw == WRITE) {
1858 loff_t final_size = offset + count;
1859
1860 if (final_size > inode->i_size) {
1861 /* Credits for sb + inode write */
1862 handle = ext3_journal_start(inode, 2);
1863 if (IS_ERR(handle)) {
1864 ret = PTR_ERR(handle);
1865 goto out;
1866 }
1867 ret = ext3_orphan_add(handle, inode);
1868 if (ret) {
1869 ext3_journal_stop(handle);
1870 goto out;
1871 }
1872 orphan = 1;
1873 ei->i_disksize = inode->i_size;
1874 ext3_journal_stop(handle);
1875 }
1876 }
1877
1878retry:
1879 ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
1880 ext3_get_block);
1881 /*
1882 * In case of error extending write may have instantiated a few
1883 * blocks outside i_size. Trim these off again.
1884 */
1885 if (unlikely((rw & WRITE) && ret < 0)) {
1886 loff_t isize = i_size_read(inode);
1887 loff_t end = offset + iov_length(iov, nr_segs);
1888
1889 if (end > isize)
1890 ext3_truncate_failed_direct_write(inode);
1891 }
1892 if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
1893 goto retry;
1894
1895 if (orphan) {
1896 int err;
1897
1898 /* Credits for sb + inode write */
1899 handle = ext3_journal_start(inode, 2);
1900 if (IS_ERR(handle)) {
1901 /* This is really bad luck. We've written the data
1902 * but cannot extend i_size. Truncate allocated blocks
1903 * and pretend the write failed... */
1904 ext3_truncate_failed_direct_write(inode);
1905 ret = PTR_ERR(handle);
1906 goto out;
1907 }
1908 if (inode->i_nlink)
1909 ext3_orphan_del(handle, inode);
1910 if (ret > 0) {
1911 loff_t end = offset + ret;
1912 if (end > inode->i_size) {
1913 ei->i_disksize = end;
1914 i_size_write(inode, end);
1915 /*
1916 * We're going to return a positive `ret'
1917 * here due to non-zero-length I/O, so there's
1918 * no way of reporting error returns from
1919 * ext3_mark_inode_dirty() to userspace. So
1920 * ignore it.
1921 */
1922 ext3_mark_inode_dirty(handle, inode);
1923 }
1924 }
1925 err = ext3_journal_stop(handle);
1926 if (ret == 0)
1927 ret = err;
1928 }
1929out:
1930 trace_ext3_direct_IO_exit(inode, offset,
1931 iov_length(iov, nr_segs), rw, ret);
1932 return ret;
1933}
1934
1935/*
1936 * Pages can be marked dirty completely asynchronously from ext3's journalling
1937 * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do
1938 * much here because ->set_page_dirty is called under VFS locks. The page is
1939 * not necessarily locked.
1940 *
1941 * We cannot just dirty the page and leave attached buffers clean, because the
1942 * buffers' dirty state is "definitive". We cannot just set the buffers dirty
1943 * or jbddirty because all the journalling code will explode.
1944 *
1945 * So what we do is to mark the page "pending dirty" and next time writepage
1946 * is called, propagate that into the buffers appropriately.
1947 */
1948static int ext3_journalled_set_page_dirty(struct page *page)
1949{
1950 SetPageChecked(page);
1951 return __set_page_dirty_nobuffers(page);
1952}
1953
1954static const struct address_space_operations ext3_ordered_aops = {
1955 .readpage = ext3_readpage,
1956 .readpages = ext3_readpages,
1957 .writepage = ext3_ordered_writepage,
1958 .write_begin = ext3_write_begin,
1959 .write_end = ext3_ordered_write_end,
1960 .bmap = ext3_bmap,
1961 .invalidatepage = ext3_invalidatepage,
1962 .releasepage = ext3_releasepage,
1963 .direct_IO = ext3_direct_IO,
1964 .migratepage = buffer_migrate_page,
1965 .is_partially_uptodate = block_is_partially_uptodate,
1966 .error_remove_page = generic_error_remove_page,
1967};
1968
1969static const struct address_space_operations ext3_writeback_aops = {
1970 .readpage = ext3_readpage,
1971 .readpages = ext3_readpages,
1972 .writepage = ext3_writeback_writepage,
1973 .write_begin = ext3_write_begin,
1974 .write_end = ext3_writeback_write_end,
1975 .bmap = ext3_bmap,
1976 .invalidatepage = ext3_invalidatepage,
1977 .releasepage = ext3_releasepage,
1978 .direct_IO = ext3_direct_IO,
1979 .migratepage = buffer_migrate_page,
1980 .is_partially_uptodate = block_is_partially_uptodate,
1981 .error_remove_page = generic_error_remove_page,
1982};
1983
1984static const struct address_space_operations ext3_journalled_aops = {
1985 .readpage = ext3_readpage,
1986 .readpages = ext3_readpages,
1987 .writepage = ext3_journalled_writepage,
1988 .write_begin = ext3_write_begin,
1989 .write_end = ext3_journalled_write_end,
1990 .set_page_dirty = ext3_journalled_set_page_dirty,
1991 .bmap = ext3_bmap,
1992 .invalidatepage = ext3_invalidatepage,
1993 .releasepage = ext3_releasepage,
1994 .is_partially_uptodate = block_is_partially_uptodate,
1995 .error_remove_page = generic_error_remove_page,
1996};
1997
1998void ext3_set_aops(struct inode *inode)
1999{
2000 if (ext3_should_order_data(inode))
2001 inode->i_mapping->a_ops = &ext3_ordered_aops;
2002 else if (ext3_should_writeback_data(inode))
2003 inode->i_mapping->a_ops = &ext3_writeback_aops;
2004 else
2005 inode->i_mapping->a_ops = &ext3_journalled_aops;
2006}
2007
2008/*
2009 * ext3_block_truncate_page() zeroes out a mapping from file offset `from'
2010 * up to the end of the block which corresponds to `from'.
2011 * This required during truncate. We need to physically zero the tail end
2012 * of that block so it doesn't yield old data if the file is later grown.
2013 */
2014static int ext3_block_truncate_page(struct inode *inode, loff_t from)
2015{
2016 ext3_fsblk_t index = from >> PAGE_CACHE_SHIFT;
2017 unsigned offset = from & (PAGE_CACHE_SIZE - 1);
2018 unsigned blocksize, iblock, length, pos;
2019 struct page *page;
2020 handle_t *handle = NULL;
2021 struct buffer_head *bh;
2022 int err = 0;
2023
2024 /* Truncated on block boundary - nothing to do */
2025 blocksize = inode->i_sb->s_blocksize;
2026 if ((from & (blocksize - 1)) == 0)
2027 return 0;
2028
2029 page = grab_cache_page(inode->i_mapping, index);
2030 if (!page)
2031 return -ENOMEM;
2032 length = blocksize - (offset & (blocksize - 1));
2033 iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
2034
2035 if (!page_has_buffers(page))
2036 create_empty_buffers(page, blocksize, 0);
2037
2038 /* Find the buffer that contains "offset" */
2039 bh = page_buffers(page);
2040 pos = blocksize;
2041 while (offset >= pos) {
2042 bh = bh->b_this_page;
2043 iblock++;
2044 pos += blocksize;
2045 }
2046
2047 err = 0;
2048 if (buffer_freed(bh)) {
2049 BUFFER_TRACE(bh, "freed: skip");
2050 goto unlock;
2051 }
2052
2053 if (!buffer_mapped(bh)) {
2054 BUFFER_TRACE(bh, "unmapped");
2055 ext3_get_block(inode, iblock, bh, 0);
2056 /* unmapped? It's a hole - nothing to do */
2057 if (!buffer_mapped(bh)) {
2058 BUFFER_TRACE(bh, "still unmapped");
2059 goto unlock;
2060 }
2061 }
2062
2063 /* Ok, it's mapped. Make sure it's up-to-date */
2064 if (PageUptodate(page))
2065 set_buffer_uptodate(bh);
2066
2067 if (!buffer_uptodate(bh)) {
2068 err = -EIO;
2069 ll_rw_block(READ, 1, &bh);
2070 wait_on_buffer(bh);
2071 /* Uhhuh. Read error. Complain and punt. */
2072 if (!buffer_uptodate(bh))
2073 goto unlock;
2074 }
2075
2076 /* data=writeback mode doesn't need transaction to zero-out data */
2077 if (!ext3_should_writeback_data(inode)) {
2078 /* We journal at most one block */
2079 handle = ext3_journal_start(inode, 1);
2080 if (IS_ERR(handle)) {
2081 clear_highpage(page);
2082 flush_dcache_page(page);
2083 err = PTR_ERR(handle);
2084 goto unlock;
2085 }
2086 }
2087
2088 if (ext3_should_journal_data(inode)) {
2089 BUFFER_TRACE(bh, "get write access");
2090 err = ext3_journal_get_write_access(handle, bh);
2091 if (err)
2092 goto stop;
2093 }
2094
2095 zero_user(page, offset, length);
2096 BUFFER_TRACE(bh, "zeroed end of block");
2097
2098 err = 0;
2099 if (ext3_should_journal_data(inode)) {
2100 err = ext3_journal_dirty_metadata(handle, bh);
2101 } else {
2102 if (ext3_should_order_data(inode))
2103 err = ext3_journal_dirty_data(handle, bh);
2104 mark_buffer_dirty(bh);
2105 }
2106stop:
2107 if (handle)
2108 ext3_journal_stop(handle);
2109
2110unlock:
2111 unlock_page(page);
2112 page_cache_release(page);
2113 return err;
2114}
2115
2116/*
2117 * Probably it should be a library function... search for first non-zero word
2118 * or memcmp with zero_page, whatever is better for particular architecture.
2119 * Linus?
2120 */
2121static inline int all_zeroes(__le32 *p, __le32 *q)
2122{
2123 while (p < q)
2124 if (*p++)
2125 return 0;
2126 return 1;
2127}
2128
2129/**
2130 * ext3_find_shared - find the indirect blocks for partial truncation.
2131 * @inode: inode in question
2132 * @depth: depth of the affected branch
2133 * @offsets: offsets of pointers in that branch (see ext3_block_to_path)
2134 * @chain: place to store the pointers to partial indirect blocks
2135 * @top: place to the (detached) top of branch
2136 *
2137 * This is a helper function used by ext3_truncate().
2138 *
2139 * When we do truncate() we may have to clean the ends of several
2140 * indirect blocks but leave the blocks themselves alive. Block is
2141 * partially truncated if some data below the new i_size is referred
2142 * from it (and it is on the path to the first completely truncated
2143 * data block, indeed). We have to free the top of that path along
2144 * with everything to the right of the path. Since no allocation
2145 * past the truncation point is possible until ext3_truncate()
2146 * finishes, we may safely do the latter, but top of branch may
2147 * require special attention - pageout below the truncation point
2148 * might try to populate it.
2149 *
2150 * We atomically detach the top of branch from the tree, store the
2151 * block number of its root in *@top, pointers to buffer_heads of
2152 * partially truncated blocks - in @chain[].bh and pointers to
2153 * their last elements that should not be removed - in
2154 * @chain[].p. Return value is the pointer to last filled element
2155 * of @chain.
2156 *
2157 * The work left to caller to do the actual freeing of subtrees:
2158 * a) free the subtree starting from *@top
2159 * b) free the subtrees whose roots are stored in
2160 * (@chain[i].p+1 .. end of @chain[i].bh->b_data)
2161 * c) free the subtrees growing from the inode past the @chain[0].
2162 * (no partially truncated stuff there). */
2163
2164static Indirect *ext3_find_shared(struct inode *inode, int depth,
2165 int offsets[4], Indirect chain[4], __le32 *top)
2166{
2167 Indirect *partial, *p;
2168 int k, err;
2169
2170 *top = 0;
2171 /* Make k index the deepest non-null offset + 1 */
2172 for (k = depth; k > 1 && !offsets[k-1]; k--)
2173 ;
2174 partial = ext3_get_branch(inode, k, offsets, chain, &err);
2175 /* Writer: pointers */
2176 if (!partial)
2177 partial = chain + k-1;
2178 /*
2179 * If the branch acquired continuation since we've looked at it -
2180 * fine, it should all survive and (new) top doesn't belong to us.
2181 */
2182 if (!partial->key && *partial->p)
2183 /* Writer: end */
2184 goto no_top;
2185 for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
2186 ;
2187 /*
2188 * OK, we've found the last block that must survive. The rest of our
2189 * branch should be detached before unlocking. However, if that rest
2190 * of branch is all ours and does not grow immediately from the inode
2191 * it's easier to cheat and just decrement partial->p.
2192 */
2193 if (p == chain + k - 1 && p > chain) {
2194 p->p--;
2195 } else {
2196 *top = *p->p;
2197 /* Nope, don't do this in ext3. Must leave the tree intact */
2198#if 0
2199 *p->p = 0;
2200#endif
2201 }
2202 /* Writer: end */
2203
2204 while(partial > p) {
2205 brelse(partial->bh);
2206 partial--;
2207 }
2208no_top:
2209 return partial;
2210}
2211
2212/*
2213 * Zero a number of block pointers in either an inode or an indirect block.
2214 * If we restart the transaction we must again get write access to the
2215 * indirect block for further modification.
2216 *
2217 * We release `count' blocks on disk, but (last - first) may be greater
2218 * than `count' because there can be holes in there.
2219 */
2220static void ext3_clear_blocks(handle_t *handle, struct inode *inode,
2221 struct buffer_head *bh, ext3_fsblk_t block_to_free,
2222 unsigned long count, __le32 *first, __le32 *last)
2223{
2224 __le32 *p;
2225 if (try_to_extend_transaction(handle, inode)) {
2226 if (bh) {
2227 BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
2228 if (ext3_journal_dirty_metadata(handle, bh))
2229 return;
2230 }
2231 ext3_mark_inode_dirty(handle, inode);
2232 truncate_restart_transaction(handle, inode);
2233 if (bh) {
2234 BUFFER_TRACE(bh, "retaking write access");
2235 if (ext3_journal_get_write_access(handle, bh))
2236 return;
2237 }
2238 }
2239
2240 /*
2241 * Any buffers which are on the journal will be in memory. We find
2242 * them on the hash table so journal_revoke() will run journal_forget()
2243 * on them. We've already detached each block from the file, so
2244 * bforget() in journal_forget() should be safe.
2245 *
2246 * AKPM: turn on bforget in journal_forget()!!!
2247 */
2248 for (p = first; p < last; p++) {
2249 u32 nr = le32_to_cpu(*p);
2250 if (nr) {
2251 struct buffer_head *bh;
2252
2253 *p = 0;
2254 bh = sb_find_get_block(inode->i_sb, nr);
2255 ext3_forget(handle, 0, inode, bh, nr);
2256 }
2257 }
2258
2259 ext3_free_blocks(handle, inode, block_to_free, count);
2260}
2261
2262/**
2263 * ext3_free_data - free a list of data blocks
2264 * @handle: handle for this transaction
2265 * @inode: inode we are dealing with
2266 * @this_bh: indirect buffer_head which contains *@first and *@last
2267 * @first: array of block numbers
2268 * @last: points immediately past the end of array
2269 *
2270 * We are freeing all blocks referred from that array (numbers are stored as
2271 * little-endian 32-bit) and updating @inode->i_blocks appropriately.
2272 *
2273 * We accumulate contiguous runs of blocks to free. Conveniently, if these
2274 * blocks are contiguous then releasing them at one time will only affect one
2275 * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
2276 * actually use a lot of journal space.
2277 *
2278 * @this_bh will be %NULL if @first and @last point into the inode's direct
2279 * block pointers.
2280 */
2281static void ext3_free_data(handle_t *handle, struct inode *inode,
2282 struct buffer_head *this_bh,
2283 __le32 *first, __le32 *last)
2284{
2285 ext3_fsblk_t block_to_free = 0; /* Starting block # of a run */
2286 unsigned long count = 0; /* Number of blocks in the run */
2287 __le32 *block_to_free_p = NULL; /* Pointer into inode/ind
2288 corresponding to
2289 block_to_free */
2290 ext3_fsblk_t nr; /* Current block # */
2291 __le32 *p; /* Pointer into inode/ind
2292 for current block */
2293 int err;
2294
2295 if (this_bh) { /* For indirect block */
2296 BUFFER_TRACE(this_bh, "get_write_access");
2297 err = ext3_journal_get_write_access(handle, this_bh);
2298 /* Important: if we can't update the indirect pointers
2299 * to the blocks, we can't free them. */
2300 if (err)
2301 return;
2302 }
2303
2304 for (p = first; p < last; p++) {
2305 nr = le32_to_cpu(*p);
2306 if (nr) {
2307 /* accumulate blocks to free if they're contiguous */
2308 if (count == 0) {
2309 block_to_free = nr;
2310 block_to_free_p = p;
2311 count = 1;
2312 } else if (nr == block_to_free + count) {
2313 count++;
2314 } else {
2315 ext3_clear_blocks(handle, inode, this_bh,
2316 block_to_free,
2317 count, block_to_free_p, p);
2318 block_to_free = nr;
2319 block_to_free_p = p;
2320 count = 1;
2321 }
2322 }
2323 }
2324
2325 if (count > 0)
2326 ext3_clear_blocks(handle, inode, this_bh, block_to_free,
2327 count, block_to_free_p, p);
2328
2329 if (this_bh) {
2330 BUFFER_TRACE(this_bh, "call ext3_journal_dirty_metadata");
2331
2332 /*
2333 * The buffer head should have an attached journal head at this
2334 * point. However, if the data is corrupted and an indirect
2335 * block pointed to itself, it would have been detached when
2336 * the block was cleared. Check for this instead of OOPSing.
2337 */
2338 if (bh2jh(this_bh))
2339 ext3_journal_dirty_metadata(handle, this_bh);
2340 else
2341 ext3_error(inode->i_sb, "ext3_free_data",
2342 "circular indirect block detected, "
2343 "inode=%lu, block=%llu",
2344 inode->i_ino,
2345 (unsigned long long)this_bh->b_blocknr);
2346 }
2347}
2348
2349/**
2350 * ext3_free_branches - free an array of branches
2351 * @handle: JBD handle for this transaction
2352 * @inode: inode we are dealing with
2353 * @parent_bh: the buffer_head which contains *@first and *@last
2354 * @first: array of block numbers
2355 * @last: pointer immediately past the end of array
2356 * @depth: depth of the branches to free
2357 *
2358 * We are freeing all blocks referred from these branches (numbers are
2359 * stored as little-endian 32-bit) and updating @inode->i_blocks
2360 * appropriately.
2361 */
2362static void ext3_free_branches(handle_t *handle, struct inode *inode,
2363 struct buffer_head *parent_bh,
2364 __le32 *first, __le32 *last, int depth)
2365{
2366 ext3_fsblk_t nr;
2367 __le32 *p;
2368
2369 if (is_handle_aborted(handle))
2370 return;
2371
2372 if (depth--) {
2373 struct buffer_head *bh;
2374 int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
2375 p = last;
2376 while (--p >= first) {
2377 nr = le32_to_cpu(*p);
2378 if (!nr)
2379 continue; /* A hole */
2380
2381 /* Go read the buffer for the next level down */
2382 bh = sb_bread(inode->i_sb, nr);
2383
2384 /*
2385 * A read failure? Report error and clear slot
2386 * (should be rare).
2387 */
2388 if (!bh) {
2389 ext3_error(inode->i_sb, "ext3_free_branches",
2390 "Read failure, inode=%lu, block="E3FSBLK,
2391 inode->i_ino, nr);
2392 continue;
2393 }
2394
2395 /* This zaps the entire block. Bottom up. */
2396 BUFFER_TRACE(bh, "free child branches");
2397 ext3_free_branches(handle, inode, bh,
2398 (__le32*)bh->b_data,
2399 (__le32*)bh->b_data + addr_per_block,
2400 depth);
2401
2402 /*
2403 * Everything below this this pointer has been
2404 * released. Now let this top-of-subtree go.
2405 *
2406 * We want the freeing of this indirect block to be
2407 * atomic in the journal with the updating of the
2408 * bitmap block which owns it. So make some room in
2409 * the journal.
2410 *
2411 * We zero the parent pointer *after* freeing its
2412 * pointee in the bitmaps, so if extend_transaction()
2413 * for some reason fails to put the bitmap changes and
2414 * the release into the same transaction, recovery
2415 * will merely complain about releasing a free block,
2416 * rather than leaking blocks.
2417 */
2418 if (is_handle_aborted(handle))
2419 return;
2420 if (try_to_extend_transaction(handle, inode)) {
2421 ext3_mark_inode_dirty(handle, inode);
2422 truncate_restart_transaction(handle, inode);
2423 }
2424
2425 /*
2426 * We've probably journalled the indirect block several
2427 * times during the truncate. But it's no longer
2428 * needed and we now drop it from the transaction via
2429 * journal_revoke().
2430 *
2431 * That's easy if it's exclusively part of this
2432 * transaction. But if it's part of the committing
2433 * transaction then journal_forget() will simply
2434 * brelse() it. That means that if the underlying
2435 * block is reallocated in ext3_get_block(),
2436 * unmap_underlying_metadata() will find this block
2437 * and will try to get rid of it. damn, damn. Thus
2438 * we don't allow a block to be reallocated until
2439 * a transaction freeing it has fully committed.
2440 *
2441 * We also have to make sure journal replay after a
2442 * crash does not overwrite non-journaled data blocks
2443 * with old metadata when the block got reallocated for
2444 * data. Thus we have to store a revoke record for a
2445 * block in the same transaction in which we free the
2446 * block.
2447 */
2448 ext3_forget(handle, 1, inode, bh, bh->b_blocknr);
2449
2450 ext3_free_blocks(handle, inode, nr, 1);
2451
2452 if (parent_bh) {
2453 /*
2454 * The block which we have just freed is
2455 * pointed to by an indirect block: journal it
2456 */
2457 BUFFER_TRACE(parent_bh, "get_write_access");
2458 if (!ext3_journal_get_write_access(handle,
2459 parent_bh)){
2460 *p = 0;
2461 BUFFER_TRACE(parent_bh,
2462 "call ext3_journal_dirty_metadata");
2463 ext3_journal_dirty_metadata(handle,
2464 parent_bh);
2465 }
2466 }
2467 }
2468 } else {
2469 /* We have reached the bottom of the tree. */
2470 BUFFER_TRACE(parent_bh, "free data blocks");
2471 ext3_free_data(handle, inode, parent_bh, first, last);
2472 }
2473}
2474
2475int ext3_can_truncate(struct inode *inode)
2476{
2477 if (S_ISREG(inode->i_mode))
2478 return 1;
2479 if (S_ISDIR(inode->i_mode))
2480 return 1;
2481 if (S_ISLNK(inode->i_mode))
2482 return !ext3_inode_is_fast_symlink(inode);
2483 return 0;
2484}
2485
2486/*
2487 * ext3_truncate()
2488 *
2489 * We block out ext3_get_block() block instantiations across the entire
2490 * transaction, and VFS/VM ensures that ext3_truncate() cannot run
2491 * simultaneously on behalf of the same inode.
2492 *
2493 * As we work through the truncate and commmit bits of it to the journal there
2494 * is one core, guiding principle: the file's tree must always be consistent on
2495 * disk. We must be able to restart the truncate after a crash.
2496 *
2497 * The file's tree may be transiently inconsistent in memory (although it
2498 * probably isn't), but whenever we close off and commit a journal transaction,
2499 * the contents of (the filesystem + the journal) must be consistent and
2500 * restartable. It's pretty simple, really: bottom up, right to left (although
2501 * left-to-right works OK too).
2502 *
2503 * Note that at recovery time, journal replay occurs *before* the restart of
2504 * truncate against the orphan inode list.
2505 *
2506 * The committed inode has the new, desired i_size (which is the same as
2507 * i_disksize in this case). After a crash, ext3_orphan_cleanup() will see
2508 * that this inode's truncate did not complete and it will again call
2509 * ext3_truncate() to have another go. So there will be instantiated blocks
2510 * to the right of the truncation point in a crashed ext3 filesystem. But
2511 * that's fine - as long as they are linked from the inode, the post-crash
2512 * ext3_truncate() run will find them and release them.
2513 */
2514void ext3_truncate(struct inode *inode)
2515{
2516 handle_t *handle;
2517 struct ext3_inode_info *ei = EXT3_I(inode);
2518 __le32 *i_data = ei->i_data;
2519 int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
2520 int offsets[4];
2521 Indirect chain[4];
2522 Indirect *partial;
2523 __le32 nr = 0;
2524 int n;
2525 long last_block;
2526 unsigned blocksize = inode->i_sb->s_blocksize;
2527
2528 trace_ext3_truncate_enter(inode);
2529
2530 if (!ext3_can_truncate(inode))
2531 goto out_notrans;
2532
2533 if (inode->i_size == 0 && ext3_should_writeback_data(inode))
2534 ext3_set_inode_state(inode, EXT3_STATE_FLUSH_ON_CLOSE);
2535
2536 handle = start_transaction(inode);
2537 if (IS_ERR(handle))
2538 goto out_notrans;
2539
2540 last_block = (inode->i_size + blocksize-1)
2541 >> EXT3_BLOCK_SIZE_BITS(inode->i_sb);
2542 n = ext3_block_to_path(inode, last_block, offsets, NULL);
2543 if (n == 0)
2544 goto out_stop; /* error */
2545
2546 /*
2547 * OK. This truncate is going to happen. We add the inode to the
2548 * orphan list, so that if this truncate spans multiple transactions,
2549 * and we crash, we will resume the truncate when the filesystem
2550 * recovers. It also marks the inode dirty, to catch the new size.
2551 *
2552 * Implication: the file must always be in a sane, consistent
2553 * truncatable state while each transaction commits.
2554 */
2555 if (ext3_orphan_add(handle, inode))
2556 goto out_stop;
2557
2558 /*
2559 * The orphan list entry will now protect us from any crash which
2560 * occurs before the truncate completes, so it is now safe to propagate
2561 * the new, shorter inode size (held for now in i_size) into the
2562 * on-disk inode. We do this via i_disksize, which is the value which
2563 * ext3 *really* writes onto the disk inode.
2564 */
2565 ei->i_disksize = inode->i_size;
2566
2567 /*
2568 * From here we block out all ext3_get_block() callers who want to
2569 * modify the block allocation tree.
2570 */
2571 mutex_lock(&ei->truncate_mutex);
2572
2573 if (n == 1) { /* direct blocks */
2574 ext3_free_data(handle, inode, NULL, i_data+offsets[0],
2575 i_data + EXT3_NDIR_BLOCKS);
2576 goto do_indirects;
2577 }
2578
2579 partial = ext3_find_shared(inode, n, offsets, chain, &nr);
2580 /* Kill the top of shared branch (not detached) */
2581 if (nr) {
2582 if (partial == chain) {
2583 /* Shared branch grows from the inode */
2584 ext3_free_branches(handle, inode, NULL,
2585 &nr, &nr+1, (chain+n-1) - partial);
2586 *partial->p = 0;
2587 /*
2588 * We mark the inode dirty prior to restart,
2589 * and prior to stop. No need for it here.
2590 */
2591 } else {
2592 /* Shared branch grows from an indirect block */
2593 ext3_free_branches(handle, inode, partial->bh,
2594 partial->p,
2595 partial->p+1, (chain+n-1) - partial);
2596 }
2597 }
2598 /* Clear the ends of indirect blocks on the shared branch */
2599 while (partial > chain) {
2600 ext3_free_branches(handle, inode, partial->bh, partial->p + 1,
2601 (__le32*)partial->bh->b_data+addr_per_block,
2602 (chain+n-1) - partial);
2603 BUFFER_TRACE(partial->bh, "call brelse");
2604 brelse (partial->bh);
2605 partial--;
2606 }
2607do_indirects:
2608 /* Kill the remaining (whole) subtrees */
2609 switch (offsets[0]) {
2610 default:
2611 nr = i_data[EXT3_IND_BLOCK];
2612 if (nr) {
2613 ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
2614 i_data[EXT3_IND_BLOCK] = 0;
2615 }
2616 case EXT3_IND_BLOCK:
2617 nr = i_data[EXT3_DIND_BLOCK];
2618 if (nr) {
2619 ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
2620 i_data[EXT3_DIND_BLOCK] = 0;
2621 }
2622 case EXT3_DIND_BLOCK:
2623 nr = i_data[EXT3_TIND_BLOCK];
2624 if (nr) {
2625 ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
2626 i_data[EXT3_TIND_BLOCK] = 0;
2627 }
2628 case EXT3_TIND_BLOCK:
2629 ;
2630 }
2631
2632 ext3_discard_reservation(inode);
2633
2634 mutex_unlock(&ei->truncate_mutex);
2635 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
2636 ext3_mark_inode_dirty(handle, inode);
2637
2638 /*
2639 * In a multi-transaction truncate, we only make the final transaction
2640 * synchronous
2641 */
2642 if (IS_SYNC(inode))
2643 handle->h_sync = 1;
2644out_stop:
2645 /*
2646 * If this was a simple ftruncate(), and the file will remain alive
2647 * then we need to clear up the orphan record which we created above.
2648 * However, if this was a real unlink then we were called by
2649 * ext3_evict_inode(), and we allow that function to clean up the
2650 * orphan info for us.
2651 */
2652 if (inode->i_nlink)
2653 ext3_orphan_del(handle, inode);
2654
2655 ext3_journal_stop(handle);
2656 trace_ext3_truncate_exit(inode);
2657 return;
2658out_notrans:
2659 /*
2660 * Delete the inode from orphan list so that it doesn't stay there
2661 * forever and trigger assertion on umount.
2662 */
2663 if (inode->i_nlink)
2664 ext3_orphan_del(NULL, inode);
2665 trace_ext3_truncate_exit(inode);
2666}
2667
2668static ext3_fsblk_t ext3_get_inode_block(struct super_block *sb,
2669 unsigned long ino, struct ext3_iloc *iloc)
2670{
2671 unsigned long block_group;
2672 unsigned long offset;
2673 ext3_fsblk_t block;
2674 struct ext3_group_desc *gdp;
2675
2676 if (!ext3_valid_inum(sb, ino)) {
2677 /*
2678 * This error is already checked for in namei.c unless we are
2679 * looking at an NFS filehandle, in which case no error
2680 * report is needed
2681 */
2682 return 0;
2683 }
2684
2685 block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
2686 gdp = ext3_get_group_desc(sb, block_group, NULL);
2687 if (!gdp)
2688 return 0;
2689 /*
2690 * Figure out the offset within the block group inode table
2691 */
2692 offset = ((ino - 1) % EXT3_INODES_PER_GROUP(sb)) *
2693 EXT3_INODE_SIZE(sb);
2694 block = le32_to_cpu(gdp->bg_inode_table) +
2695 (offset >> EXT3_BLOCK_SIZE_BITS(sb));
2696
2697 iloc->block_group = block_group;
2698 iloc->offset = offset & (EXT3_BLOCK_SIZE(sb) - 1);
2699 return block;
2700}
2701
2702/*
2703 * ext3_get_inode_loc returns with an extra refcount against the inode's
2704 * underlying buffer_head on success. If 'in_mem' is true, we have all
2705 * data in memory that is needed to recreate the on-disk version of this
2706 * inode.
2707 */
2708static int __ext3_get_inode_loc(struct inode *inode,
2709 struct ext3_iloc *iloc, int in_mem)
2710{
2711 ext3_fsblk_t block;
2712 struct buffer_head *bh;
2713
2714 block = ext3_get_inode_block(inode->i_sb, inode->i_ino, iloc);
2715 if (!block)
2716 return -EIO;
2717
2718 bh = sb_getblk(inode->i_sb, block);
2719 if (!bh) {
2720 ext3_error (inode->i_sb, "ext3_get_inode_loc",
2721 "unable to read inode block - "
2722 "inode=%lu, block="E3FSBLK,
2723 inode->i_ino, block);
2724 return -EIO;
2725 }
2726 if (!buffer_uptodate(bh)) {
2727 lock_buffer(bh);
2728
2729 /*
2730 * If the buffer has the write error flag, we have failed
2731 * to write out another inode in the same block. In this
2732 * case, we don't have to read the block because we may
2733 * read the old inode data successfully.
2734 */
2735 if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
2736 set_buffer_uptodate(bh);
2737
2738 if (buffer_uptodate(bh)) {
2739 /* someone brought it uptodate while we waited */
2740 unlock_buffer(bh);
2741 goto has_buffer;
2742 }
2743
2744 /*
2745 * If we have all information of the inode in memory and this
2746 * is the only valid inode in the block, we need not read the
2747 * block.
2748 */
2749 if (in_mem) {
2750 struct buffer_head *bitmap_bh;
2751 struct ext3_group_desc *desc;
2752 int inodes_per_buffer;
2753 int inode_offset, i;
2754 int block_group;
2755 int start;
2756
2757 block_group = (inode->i_ino - 1) /
2758 EXT3_INODES_PER_GROUP(inode->i_sb);
2759 inodes_per_buffer = bh->b_size /
2760 EXT3_INODE_SIZE(inode->i_sb);
2761 inode_offset = ((inode->i_ino - 1) %
2762 EXT3_INODES_PER_GROUP(inode->i_sb));
2763 start = inode_offset & ~(inodes_per_buffer - 1);
2764
2765 /* Is the inode bitmap in cache? */
2766 desc = ext3_get_group_desc(inode->i_sb,
2767 block_group, NULL);
2768 if (!desc)
2769 goto make_io;
2770
2771 bitmap_bh = sb_getblk(inode->i_sb,
2772 le32_to_cpu(desc->bg_inode_bitmap));
2773 if (!bitmap_bh)
2774 goto make_io;
2775
2776 /*
2777 * If the inode bitmap isn't in cache then the
2778 * optimisation may end up performing two reads instead
2779 * of one, so skip it.
2780 */
2781 if (!buffer_uptodate(bitmap_bh)) {
2782 brelse(bitmap_bh);
2783 goto make_io;
2784 }
2785 for (i = start; i < start + inodes_per_buffer; i++) {
2786 if (i == inode_offset)
2787 continue;
2788 if (ext3_test_bit(i, bitmap_bh->b_data))
2789 break;
2790 }
2791 brelse(bitmap_bh);
2792 if (i == start + inodes_per_buffer) {
2793 /* all other inodes are free, so skip I/O */
2794 memset(bh->b_data, 0, bh->b_size);
2795 set_buffer_uptodate(bh);
2796 unlock_buffer(bh);
2797 goto has_buffer;
2798 }
2799 }
2800
2801make_io:
2802 /*
2803 * There are other valid inodes in the buffer, this inode
2804 * has in-inode xattrs, or we don't have this inode in memory.
2805 * Read the block from disk.
2806 */
2807 trace_ext3_load_inode(inode);
2808 get_bh(bh);
2809 bh->b_end_io = end_buffer_read_sync;
2810 submit_bh(READ | REQ_META | REQ_PRIO, bh);
2811 wait_on_buffer(bh);
2812 if (!buffer_uptodate(bh)) {
2813 ext3_error(inode->i_sb, "ext3_get_inode_loc",
2814 "unable to read inode block - "
2815 "inode=%lu, block="E3FSBLK,
2816 inode->i_ino, block);
2817 brelse(bh);
2818 return -EIO;
2819 }
2820 }
2821has_buffer:
2822 iloc->bh = bh;
2823 return 0;
2824}
2825
2826int ext3_get_inode_loc(struct inode *inode, struct ext3_iloc *iloc)
2827{
2828 /* We have all inode data except xattrs in memory here. */
2829 return __ext3_get_inode_loc(inode, iloc,
2830 !ext3_test_inode_state(inode, EXT3_STATE_XATTR));
2831}
2832
2833void ext3_set_inode_flags(struct inode *inode)
2834{
2835 unsigned int flags = EXT3_I(inode)->i_flags;
2836
2837 inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
2838 if (flags & EXT3_SYNC_FL)
2839 inode->i_flags |= S_SYNC;
2840 if (flags & EXT3_APPEND_FL)
2841 inode->i_flags |= S_APPEND;
2842 if (flags & EXT3_IMMUTABLE_FL)
2843 inode->i_flags |= S_IMMUTABLE;
2844 if (flags & EXT3_NOATIME_FL)
2845 inode->i_flags |= S_NOATIME;
2846 if (flags & EXT3_DIRSYNC_FL)
2847 inode->i_flags |= S_DIRSYNC;
2848}
2849
2850/* Propagate flags from i_flags to EXT3_I(inode)->i_flags */
2851void ext3_get_inode_flags(struct ext3_inode_info *ei)
2852{
2853 unsigned int flags = ei->vfs_inode.i_flags;
2854
2855 ei->i_flags &= ~(EXT3_SYNC_FL|EXT3_APPEND_FL|
2856 EXT3_IMMUTABLE_FL|EXT3_NOATIME_FL|EXT3_DIRSYNC_FL);
2857 if (flags & S_SYNC)
2858 ei->i_flags |= EXT3_SYNC_FL;
2859 if (flags & S_APPEND)
2860 ei->i_flags |= EXT3_APPEND_FL;
2861 if (flags & S_IMMUTABLE)
2862 ei->i_flags |= EXT3_IMMUTABLE_FL;
2863 if (flags & S_NOATIME)
2864 ei->i_flags |= EXT3_NOATIME_FL;
2865 if (flags & S_DIRSYNC)
2866 ei->i_flags |= EXT3_DIRSYNC_FL;
2867}
2868
2869struct inode *ext3_iget(struct super_block *sb, unsigned long ino)
2870{
2871 struct ext3_iloc iloc;
2872 struct ext3_inode *raw_inode;
2873 struct ext3_inode_info *ei;
2874 struct buffer_head *bh;
2875 struct inode *inode;
2876 journal_t *journal = EXT3_SB(sb)->s_journal;
2877 transaction_t *transaction;
2878 long ret;
2879 int block;
2880
2881 inode = iget_locked(sb, ino);
2882 if (!inode)
2883 return ERR_PTR(-ENOMEM);
2884 if (!(inode->i_state & I_NEW))
2885 return inode;
2886
2887 ei = EXT3_I(inode);
2888 ei->i_block_alloc_info = NULL;
2889
2890 ret = __ext3_get_inode_loc(inode, &iloc, 0);
2891 if (ret < 0)
2892 goto bad_inode;
2893 bh = iloc.bh;
2894 raw_inode = ext3_raw_inode(&iloc);
2895 inode->i_mode = le16_to_cpu(raw_inode->i_mode);
2896 inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
2897 inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
2898 if(!(test_opt (inode->i_sb, NO_UID32))) {
2899 inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
2900 inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
2901 }
2902 inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
2903 inode->i_size = le32_to_cpu(raw_inode->i_size);
2904 inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
2905 inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
2906 inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
2907 inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = inode->i_mtime.tv_nsec = 0;
2908
2909 ei->i_state_flags = 0;
2910 ei->i_dir_start_lookup = 0;
2911 ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
2912 /* We now have enough fields to check if the inode was active or not.
2913 * This is needed because nfsd might try to access dead inodes
2914 * the test is that same one that e2fsck uses
2915 * NeilBrown 1999oct15
2916 */
2917 if (inode->i_nlink == 0) {
2918 if (inode->i_mode == 0 ||
2919 !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ORPHAN_FS)) {
2920 /* this inode is deleted */
2921 brelse (bh);
2922 ret = -ESTALE;
2923 goto bad_inode;
2924 }
2925 /* The only unlinked inodes we let through here have
2926 * valid i_mode and are being read by the orphan
2927 * recovery code: that's fine, we're about to complete
2928 * the process of deleting those. */
2929 }
2930 inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
2931 ei->i_flags = le32_to_cpu(raw_inode->i_flags);
2932#ifdef EXT3_FRAGMENTS
2933 ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
2934 ei->i_frag_no = raw_inode->i_frag;
2935 ei->i_frag_size = raw_inode->i_fsize;
2936#endif
2937 ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
2938 if (!S_ISREG(inode->i_mode)) {
2939 ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
2940 } else {
2941 inode->i_size |=
2942 ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
2943 }
2944 ei->i_disksize = inode->i_size;
2945 inode->i_generation = le32_to_cpu(raw_inode->i_generation);
2946 ei->i_block_group = iloc.block_group;
2947 /*
2948 * NOTE! The in-memory inode i_data array is in little-endian order
2949 * even on big-endian machines: we do NOT byteswap the block numbers!
2950 */
2951 for (block = 0; block < EXT3_N_BLOCKS; block++)
2952 ei->i_data[block] = raw_inode->i_block[block];
2953 INIT_LIST_HEAD(&ei->i_orphan);
2954
2955 /*
2956 * Set transaction id's of transactions that have to be committed
2957 * to finish f[data]sync. We set them to currently running transaction
2958 * as we cannot be sure that the inode or some of its metadata isn't
2959 * part of the transaction - the inode could have been reclaimed and
2960 * now it is reread from disk.
2961 */
2962 if (journal) {
2963 tid_t tid;
2964
2965 spin_lock(&journal->j_state_lock);
2966 if (journal->j_running_transaction)
2967 transaction = journal->j_running_transaction;
2968 else
2969 transaction = journal->j_committing_transaction;
2970 if (transaction)
2971 tid = transaction->t_tid;
2972 else
2973 tid = journal->j_commit_sequence;
2974 spin_unlock(&journal->j_state_lock);
2975 atomic_set(&ei->i_sync_tid, tid);
2976 atomic_set(&ei->i_datasync_tid, tid);
2977 }
2978
2979 if (inode->i_ino >= EXT3_FIRST_INO(inode->i_sb) + 1 &&
2980 EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) {
2981 /*
2982 * When mke2fs creates big inodes it does not zero out
2983 * the unused bytes above EXT3_GOOD_OLD_INODE_SIZE,
2984 * so ignore those first few inodes.
2985 */
2986 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
2987 if (EXT3_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
2988 EXT3_INODE_SIZE(inode->i_sb)) {
2989 brelse (bh);
2990 ret = -EIO;
2991 goto bad_inode;
2992 }
2993 if (ei->i_extra_isize == 0) {
2994 /* The extra space is currently unused. Use it. */
2995 ei->i_extra_isize = sizeof(struct ext3_inode) -
2996 EXT3_GOOD_OLD_INODE_SIZE;
2997 } else {
2998 __le32 *magic = (void *)raw_inode +
2999 EXT3_GOOD_OLD_INODE_SIZE +
3000 ei->i_extra_isize;
3001 if (*magic == cpu_to_le32(EXT3_XATTR_MAGIC))
3002 ext3_set_inode_state(inode, EXT3_STATE_XATTR);
3003 }
3004 } else
3005 ei->i_extra_isize = 0;
3006
3007 if (S_ISREG(inode->i_mode)) {
3008 inode->i_op = &ext3_file_inode_operations;
3009 inode->i_fop = &ext3_file_operations;
3010 ext3_set_aops(inode);
3011 } else if (S_ISDIR(inode->i_mode)) {
3012 inode->i_op = &ext3_dir_inode_operations;
3013 inode->i_fop = &ext3_dir_operations;
3014 } else if (S_ISLNK(inode->i_mode)) {
3015 if (ext3_inode_is_fast_symlink(inode)) {
3016 inode->i_op = &ext3_fast_symlink_inode_operations;
3017 nd_terminate_link(ei->i_data, inode->i_size,
3018 sizeof(ei->i_data) - 1);
3019 } else {
3020 inode->i_op = &ext3_symlink_inode_operations;
3021 ext3_set_aops(inode);
3022 }
3023 } else {
3024 inode->i_op = &ext3_special_inode_operations;
3025 if (raw_inode->i_block[0])
3026 init_special_inode(inode, inode->i_mode,
3027 old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
3028 else
3029 init_special_inode(inode, inode->i_mode,
3030 new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
3031 }
3032 brelse (iloc.bh);
3033 ext3_set_inode_flags(inode);
3034 unlock_new_inode(inode);
3035 return inode;
3036
3037bad_inode:
3038 iget_failed(inode);
3039 return ERR_PTR(ret);
3040}
3041
3042/*
3043 * Post the struct inode info into an on-disk inode location in the
3044 * buffer-cache. This gobbles the caller's reference to the
3045 * buffer_head in the inode location struct.
3046 *
3047 * The caller must have write access to iloc->bh.
3048 */
3049static int ext3_do_update_inode(handle_t *handle,
3050 struct inode *inode,
3051 struct ext3_iloc *iloc)
3052{
3053 struct ext3_inode *raw_inode = ext3_raw_inode(iloc);
3054 struct ext3_inode_info *ei = EXT3_I(inode);
3055 struct buffer_head *bh = iloc->bh;
3056 int err = 0, rc, block;
3057
3058again:
3059 /* we can't allow multiple procs in here at once, its a bit racey */
3060 lock_buffer(bh);
3061
3062 /* For fields not not tracking in the in-memory inode,
3063 * initialise them to zero for new inodes. */
3064 if (ext3_test_inode_state(inode, EXT3_STATE_NEW))
3065 memset(raw_inode, 0, EXT3_SB(inode->i_sb)->s_inode_size);
3066
3067 ext3_get_inode_flags(ei);
3068 raw_inode->i_mode = cpu_to_le16(inode->i_mode);
3069 if(!(test_opt(inode->i_sb, NO_UID32))) {
3070 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
3071 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid));
3072/*
3073 * Fix up interoperability with old kernels. Otherwise, old inodes get
3074 * re-used with the upper 16 bits of the uid/gid intact
3075 */
3076 if(!ei->i_dtime) {
3077 raw_inode->i_uid_high =
3078 cpu_to_le16(high_16_bits(inode->i_uid));
3079 raw_inode->i_gid_high =
3080 cpu_to_le16(high_16_bits(inode->i_gid));
3081 } else {
3082 raw_inode->i_uid_high = 0;
3083 raw_inode->i_gid_high = 0;
3084 }
3085 } else {
3086 raw_inode->i_uid_low =
3087 cpu_to_le16(fs_high2lowuid(inode->i_uid));
3088 raw_inode->i_gid_low =
3089 cpu_to_le16(fs_high2lowgid(inode->i_gid));
3090 raw_inode->i_uid_high = 0;
3091 raw_inode->i_gid_high = 0;
3092 }
3093 raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
3094 raw_inode->i_size = cpu_to_le32(ei->i_disksize);
3095 raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
3096 raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
3097 raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
3098 raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
3099 raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
3100 raw_inode->i_flags = cpu_to_le32(ei->i_flags);
3101#ifdef EXT3_FRAGMENTS
3102 raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
3103 raw_inode->i_frag = ei->i_frag_no;
3104 raw_inode->i_fsize = ei->i_frag_size;
3105#endif
3106 raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
3107 if (!S_ISREG(inode->i_mode)) {
3108 raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
3109 } else {
3110 raw_inode->i_size_high =
3111 cpu_to_le32(ei->i_disksize >> 32);
3112 if (ei->i_disksize > 0x7fffffffULL) {
3113 struct super_block *sb = inode->i_sb;
3114 if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
3115 EXT3_FEATURE_RO_COMPAT_LARGE_FILE) ||
3116 EXT3_SB(sb)->s_es->s_rev_level ==
3117 cpu_to_le32(EXT3_GOOD_OLD_REV)) {
3118 /* If this is the first large file
3119 * created, add a flag to the superblock.
3120 */
3121 unlock_buffer(bh);
3122 err = ext3_journal_get_write_access(handle,
3123 EXT3_SB(sb)->s_sbh);
3124 if (err)
3125 goto out_brelse;
3126
3127 ext3_update_dynamic_rev(sb);
3128 EXT3_SET_RO_COMPAT_FEATURE(sb,
3129 EXT3_FEATURE_RO_COMPAT_LARGE_FILE);
3130 handle->h_sync = 1;
3131 err = ext3_journal_dirty_metadata(handle,
3132 EXT3_SB(sb)->s_sbh);
3133 /* get our lock and start over */
3134 goto again;
3135 }
3136 }
3137 }
3138 raw_inode->i_generation = cpu_to_le32(inode->i_generation);
3139 if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
3140 if (old_valid_dev(inode->i_rdev)) {
3141 raw_inode->i_block[0] =
3142 cpu_to_le32(old_encode_dev(inode->i_rdev));
3143 raw_inode->i_block[1] = 0;
3144 } else {
3145 raw_inode->i_block[0] = 0;
3146 raw_inode->i_block[1] =
3147 cpu_to_le32(new_encode_dev(inode->i_rdev));
3148 raw_inode->i_block[2] = 0;
3149 }
3150 } else for (block = 0; block < EXT3_N_BLOCKS; block++)
3151 raw_inode->i_block[block] = ei->i_data[block];
3152
3153 if (ei->i_extra_isize)
3154 raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
3155
3156 BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
3157 unlock_buffer(bh);
3158 rc = ext3_journal_dirty_metadata(handle, bh);
3159 if (!err)
3160 err = rc;
3161 ext3_clear_inode_state(inode, EXT3_STATE_NEW);
3162
3163 atomic_set(&ei->i_sync_tid, handle->h_transaction->t_tid);
3164out_brelse:
3165 brelse (bh);
3166 ext3_std_error(inode->i_sb, err);
3167 return err;
3168}
3169
3170/*
3171 * ext3_write_inode()
3172 *
3173 * We are called from a few places:
3174 *
3175 * - Within generic_file_write() for O_SYNC files.
3176 * Here, there will be no transaction running. We wait for any running
3177 * trasnaction to commit.
3178 *
3179 * - Within sys_sync(), kupdate and such.
3180 * We wait on commit, if tol to.
3181 *
3182 * - Within prune_icache() (PF_MEMALLOC == true)
3183 * Here we simply return. We can't afford to block kswapd on the
3184 * journal commit.
3185 *
3186 * In all cases it is actually safe for us to return without doing anything,
3187 * because the inode has been copied into a raw inode buffer in
3188 * ext3_mark_inode_dirty(). This is a correctness thing for O_SYNC and for
3189 * knfsd.
3190 *
3191 * Note that we are absolutely dependent upon all inode dirtiers doing the
3192 * right thing: they *must* call mark_inode_dirty() after dirtying info in
3193 * which we are interested.
3194 *
3195 * It would be a bug for them to not do this. The code:
3196 *
3197 * mark_inode_dirty(inode)
3198 * stuff();
3199 * inode->i_size = expr;
3200 *
3201 * is in error because a kswapd-driven write_inode() could occur while
3202 * `stuff()' is running, and the new i_size will be lost. Plus the inode
3203 * will no longer be on the superblock's dirty inode list.
3204 */
3205int ext3_write_inode(struct inode *inode, struct writeback_control *wbc)
3206{
3207 if (current->flags & PF_MEMALLOC)
3208 return 0;
3209
3210 if (ext3_journal_current_handle()) {
3211 jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
3212 dump_stack();
3213 return -EIO;
3214 }
3215
3216 if (wbc->sync_mode != WB_SYNC_ALL)
3217 return 0;
3218
3219 return ext3_force_commit(inode->i_sb);
3220}
3221
3222/*
3223 * ext3_setattr()
3224 *
3225 * Called from notify_change.
3226 *
3227 * We want to trap VFS attempts to truncate the file as soon as
3228 * possible. In particular, we want to make sure that when the VFS
3229 * shrinks i_size, we put the inode on the orphan list and modify
3230 * i_disksize immediately, so that during the subsequent flushing of
3231 * dirty pages and freeing of disk blocks, we can guarantee that any
3232 * commit will leave the blocks being flushed in an unused state on
3233 * disk. (On recovery, the inode will get truncated and the blocks will
3234 * be freed, so we have a strong guarantee that no future commit will
3235 * leave these blocks visible to the user.)
3236 *
3237 * Called with inode->sem down.
3238 */
3239int ext3_setattr(struct dentry *dentry, struct iattr *attr)
3240{
3241 struct inode *inode = dentry->d_inode;
3242 int error, rc = 0;
3243 const unsigned int ia_valid = attr->ia_valid;
3244
3245 error = inode_change_ok(inode, attr);
3246 if (error)
3247 return error;
3248
3249 if (is_quota_modification(inode, attr))
3250 dquot_initialize(inode);
3251 if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
3252 (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) {
3253 handle_t *handle;
3254
3255 /* (user+group)*(old+new) structure, inode write (sb,
3256 * inode block, ? - but truncate inode update has it) */
3257 handle = ext3_journal_start(inode, EXT3_MAXQUOTAS_INIT_BLOCKS(inode->i_sb)+
3258 EXT3_MAXQUOTAS_DEL_BLOCKS(inode->i_sb)+3);
3259 if (IS_ERR(handle)) {
3260 error = PTR_ERR(handle);
3261 goto err_out;
3262 }
3263 error = dquot_transfer(inode, attr);
3264 if (error) {
3265 ext3_journal_stop(handle);
3266 return error;
3267 }
3268 /* Update corresponding info in inode so that everything is in
3269 * one transaction */
3270 if (attr->ia_valid & ATTR_UID)
3271 inode->i_uid = attr->ia_uid;
3272 if (attr->ia_valid & ATTR_GID)
3273 inode->i_gid = attr->ia_gid;
3274 error = ext3_mark_inode_dirty(handle, inode);
3275 ext3_journal_stop(handle);
3276 }
3277
3278 if (attr->ia_valid & ATTR_SIZE)
3279 inode_dio_wait(inode);
3280
3281 if (S_ISREG(inode->i_mode) &&
3282 attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
3283 handle_t *handle;
3284
3285 handle = ext3_journal_start(inode, 3);
3286 if (IS_ERR(handle)) {
3287 error = PTR_ERR(handle);
3288 goto err_out;
3289 }
3290
3291 error = ext3_orphan_add(handle, inode);
3292 if (error) {
3293 ext3_journal_stop(handle);
3294 goto err_out;
3295 }
3296 EXT3_I(inode)->i_disksize = attr->ia_size;
3297 error = ext3_mark_inode_dirty(handle, inode);
3298 ext3_journal_stop(handle);
3299 if (error) {
3300 /* Some hard fs error must have happened. Bail out. */
3301 ext3_orphan_del(NULL, inode);
3302 goto err_out;
3303 }
3304 rc = ext3_block_truncate_page(inode, attr->ia_size);
3305 if (rc) {
3306 /* Cleanup orphan list and exit */
3307 handle = ext3_journal_start(inode, 3);
3308 if (IS_ERR(handle)) {
3309 ext3_orphan_del(NULL, inode);
3310 goto err_out;
3311 }
3312 ext3_orphan_del(handle, inode);
3313 ext3_journal_stop(handle);
3314 goto err_out;
3315 }
3316 }
3317
3318 if ((attr->ia_valid & ATTR_SIZE) &&
3319 attr->ia_size != i_size_read(inode)) {
3320 truncate_setsize(inode, attr->ia_size);
3321 ext3_truncate(inode);
3322 }
3323
3324 setattr_copy(inode, attr);
3325 mark_inode_dirty(inode);
3326
3327 if (ia_valid & ATTR_MODE)
3328 rc = ext3_acl_chmod(inode);
3329
3330err_out:
3331 ext3_std_error(inode->i_sb, error);
3332 if (!error)
3333 error = rc;
3334 return error;
3335}
3336
3337
3338/*
3339 * How many blocks doth make a writepage()?
3340 *
3341 * With N blocks per page, it may be:
3342 * N data blocks
3343 * 2 indirect block
3344 * 2 dindirect
3345 * 1 tindirect
3346 * N+5 bitmap blocks (from the above)
3347 * N+5 group descriptor summary blocks
3348 * 1 inode block
3349 * 1 superblock.
3350 * 2 * EXT3_SINGLEDATA_TRANS_BLOCKS for the quote files
3351 *
3352 * 3 * (N + 5) + 2 + 2 * EXT3_SINGLEDATA_TRANS_BLOCKS
3353 *
3354 * With ordered or writeback data it's the same, less the N data blocks.
3355 *
3356 * If the inode's direct blocks can hold an integral number of pages then a
3357 * page cannot straddle two indirect blocks, and we can only touch one indirect
3358 * and dindirect block, and the "5" above becomes "3".
3359 *
3360 * This still overestimates under most circumstances. If we were to pass the
3361 * start and end offsets in here as well we could do block_to_path() on each
3362 * block and work out the exact number of indirects which are touched. Pah.
3363 */
3364
3365static int ext3_writepage_trans_blocks(struct inode *inode)
3366{
3367 int bpp = ext3_journal_blocks_per_page(inode);
3368 int indirects = (EXT3_NDIR_BLOCKS % bpp) ? 5 : 3;
3369 int ret;
3370
3371 if (ext3_should_journal_data(inode))
3372 ret = 3 * (bpp + indirects) + 2;
3373 else
3374 ret = 2 * (bpp + indirects) + indirects + 2;
3375
3376#ifdef CONFIG_QUOTA
3377 /* We know that structure was already allocated during dquot_initialize so
3378 * we will be updating only the data blocks + inodes */
3379 ret += EXT3_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
3380#endif
3381
3382 return ret;
3383}
3384
3385/*
3386 * The caller must have previously called ext3_reserve_inode_write().
3387 * Give this, we know that the caller already has write access to iloc->bh.
3388 */
3389int ext3_mark_iloc_dirty(handle_t *handle,
3390 struct inode *inode, struct ext3_iloc *iloc)
3391{
3392 int err = 0;
3393
3394 /* the do_update_inode consumes one bh->b_count */
3395 get_bh(iloc->bh);
3396
3397 /* ext3_do_update_inode() does journal_dirty_metadata */
3398 err = ext3_do_update_inode(handle, inode, iloc);
3399 put_bh(iloc->bh);
3400 return err;
3401}
3402
3403/*
3404 * On success, We end up with an outstanding reference count against
3405 * iloc->bh. This _must_ be cleaned up later.
3406 */
3407
3408int
3409ext3_reserve_inode_write(handle_t *handle, struct inode *inode,
3410 struct ext3_iloc *iloc)
3411{
3412 int err = 0;
3413 if (handle) {
3414 err = ext3_get_inode_loc(inode, iloc);
3415 if (!err) {
3416 BUFFER_TRACE(iloc->bh, "get_write_access");
3417 err = ext3_journal_get_write_access(handle, iloc->bh);
3418 if (err) {
3419 brelse(iloc->bh);
3420 iloc->bh = NULL;
3421 }
3422 }
3423 }
3424 ext3_std_error(inode->i_sb, err);
3425 return err;
3426}
3427
3428/*
3429 * What we do here is to mark the in-core inode as clean with respect to inode
3430 * dirtiness (it may still be data-dirty).
3431 * This means that the in-core inode may be reaped by prune_icache
3432 * without having to perform any I/O. This is a very good thing,
3433 * because *any* task may call prune_icache - even ones which
3434 * have a transaction open against a different journal.
3435 *
3436 * Is this cheating? Not really. Sure, we haven't written the
3437 * inode out, but prune_icache isn't a user-visible syncing function.
3438 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
3439 * we start and wait on commits.
3440 *
3441 * Is this efficient/effective? Well, we're being nice to the system
3442 * by cleaning up our inodes proactively so they can be reaped
3443 * without I/O. But we are potentially leaving up to five seconds'
3444 * worth of inodes floating about which prune_icache wants us to
3445 * write out. One way to fix that would be to get prune_icache()
3446 * to do a write_super() to free up some memory. It has the desired
3447 * effect.
3448 */
3449int ext3_mark_inode_dirty(handle_t *handle, struct inode *inode)
3450{
3451 struct ext3_iloc iloc;
3452 int err;
3453
3454 might_sleep();
3455 trace_ext3_mark_inode_dirty(inode, _RET_IP_);
3456 err = ext3_reserve_inode_write(handle, inode, &iloc);
3457 if (!err)
3458 err = ext3_mark_iloc_dirty(handle, inode, &iloc);
3459 return err;
3460}
3461
3462/*
3463 * ext3_dirty_inode() is called from __mark_inode_dirty()
3464 *
3465 * We're really interested in the case where a file is being extended.
3466 * i_size has been changed by generic_commit_write() and we thus need
3467 * to include the updated inode in the current transaction.
3468 *
3469 * Also, dquot_alloc_space() will always dirty the inode when blocks
3470 * are allocated to the file.
3471 *
3472 * If the inode is marked synchronous, we don't honour that here - doing
3473 * so would cause a commit on atime updates, which we don't bother doing.
3474 * We handle synchronous inodes at the highest possible level.
3475 */
3476void ext3_dirty_inode(struct inode *inode, int flags)
3477{
3478 handle_t *current_handle = ext3_journal_current_handle();
3479 handle_t *handle;
3480
3481 handle = ext3_journal_start(inode, 2);
3482 if (IS_ERR(handle))
3483 goto out;
3484 if (current_handle &&
3485 current_handle->h_transaction != handle->h_transaction) {
3486 /* This task has a transaction open against a different fs */
3487 printk(KERN_EMERG "%s: transactions do not match!\n",
3488 __func__);
3489 } else {
3490 jbd_debug(5, "marking dirty. outer handle=%p\n",
3491 current_handle);
3492 ext3_mark_inode_dirty(handle, inode);
3493 }
3494 ext3_journal_stop(handle);
3495out:
3496 return;
3497}
3498
3499#if 0
3500/*
3501 * Bind an inode's backing buffer_head into this transaction, to prevent
3502 * it from being flushed to disk early. Unlike
3503 * ext3_reserve_inode_write, this leaves behind no bh reference and
3504 * returns no iloc structure, so the caller needs to repeat the iloc
3505 * lookup to mark the inode dirty later.
3506 */
3507static int ext3_pin_inode(handle_t *handle, struct inode *inode)
3508{
3509 struct ext3_iloc iloc;
3510
3511 int err = 0;
3512 if (handle) {
3513 err = ext3_get_inode_loc(inode, &iloc);
3514 if (!err) {
3515 BUFFER_TRACE(iloc.bh, "get_write_access");
3516 err = journal_get_write_access(handle, iloc.bh);
3517 if (!err)
3518 err = ext3_journal_dirty_metadata(handle,
3519 iloc.bh);
3520 brelse(iloc.bh);
3521 }
3522 }
3523 ext3_std_error(inode->i_sb, err);
3524 return err;
3525}
3526#endif
3527
3528int ext3_change_inode_journal_flag(struct inode *inode, int val)
3529{
3530 journal_t *journal;
3531 handle_t *handle;
3532 int err;
3533
3534 /*
3535 * We have to be very careful here: changing a data block's
3536 * journaling status dynamically is dangerous. If we write a
3537 * data block to the journal, change the status and then delete
3538 * that block, we risk forgetting to revoke the old log record
3539 * from the journal and so a subsequent replay can corrupt data.
3540 * So, first we make sure that the journal is empty and that
3541 * nobody is changing anything.
3542 */
3543
3544 journal = EXT3_JOURNAL(inode);
3545 if (is_journal_aborted(journal))
3546 return -EROFS;
3547
3548 journal_lock_updates(journal);
3549 journal_flush(journal);
3550
3551 /*
3552 * OK, there are no updates running now, and all cached data is
3553 * synced to disk. We are now in a completely consistent state
3554 * which doesn't have anything in the journal, and we know that
3555 * no filesystem updates are running, so it is safe to modify
3556 * the inode's in-core data-journaling state flag now.
3557 */
3558
3559 if (val)
3560 EXT3_I(inode)->i_flags |= EXT3_JOURNAL_DATA_FL;
3561 else
3562 EXT3_I(inode)->i_flags &= ~EXT3_JOURNAL_DATA_FL;
3563 ext3_set_aops(inode);
3564
3565 journal_unlock_updates(journal);
3566
3567 /* Finally we can mark the inode as dirty. */
3568
3569 handle = ext3_journal_start(inode, 1);
3570 if (IS_ERR(handle))
3571 return PTR_ERR(handle);
3572
3573 err = ext3_mark_inode_dirty(handle, inode);
3574 handle->h_sync = 1;
3575 ext3_journal_stop(handle);
3576 ext3_std_error(inode->i_sb, err);
3577
3578 return err;
3579}