2 * linux/fs/ext4/inode.c
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)
11 * linux/fs/minix/inode.c
13 * Copyright (C) 1991, 1992 Linus Torvalds
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)
22 * Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
25 #include <linux/module.h>
27 #include <linux/time.h>
28 #include <linux/jbd2.h>
29 #include <linux/highuid.h>
30 #include <linux/pagemap.h>
31 #include <linux/quotaops.h>
32 #include <linux/string.h>
33 #include <linux/buffer_head.h>
34 #include <linux/writeback.h>
35 #include <linux/pagevec.h>
36 #include <linux/mpage.h>
37 #include <linux/uio.h>
38 #include <linux/bio.h>
39 #include "ext4_jbd2.h"
42 #include "ext4_extents.h"
44 static inline int ext4_begin_ordered_truncate(struct inode *inode,
47 return jbd2_journal_begin_ordered_truncate(&EXT4_I(inode)->jinode,
51 static void ext4_invalidatepage(struct page *page, unsigned long offset);
54 * Test whether an inode is a fast symlink.
56 static int ext4_inode_is_fast_symlink(struct inode *inode)
58 int ea_blocks = EXT4_I(inode)->i_file_acl ?
59 (inode->i_sb->s_blocksize >> 9) : 0;
61 return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
65 * The ext4 forget function must perform a revoke if we are freeing data
66 * which has been journaled. Metadata (eg. indirect blocks) must be
67 * revoked in all cases.
69 * "bh" may be NULL: a metadata block may have been freed from memory
70 * but there may still be a record of it in the journal, and that record
71 * still needs to be revoked.
73 int ext4_forget(handle_t *handle, int is_metadata, struct inode *inode,
74 struct buffer_head *bh, ext4_fsblk_t blocknr)
80 BUFFER_TRACE(bh, "enter");
82 jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
84 bh, is_metadata, inode->i_mode,
85 test_opt(inode->i_sb, DATA_FLAGS));
87 /* Never use the revoke function if we are doing full data
88 * journaling: there is no need to, and a V1 superblock won't
89 * support it. Otherwise, only skip the revoke on un-journaled
92 if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
93 (!is_metadata && !ext4_should_journal_data(inode))) {
95 BUFFER_TRACE(bh, "call jbd2_journal_forget");
96 return ext4_journal_forget(handle, bh);
102 * data!=journal && (is_metadata || should_journal_data(inode))
104 BUFFER_TRACE(bh, "call ext4_journal_revoke");
105 err = ext4_journal_revoke(handle, blocknr, bh);
107 ext4_abort(inode->i_sb, __func__,
108 "error %d when attempting revoke", err);
109 BUFFER_TRACE(bh, "exit");
114 * Work out how many blocks we need to proceed with the next chunk of a
115 * truncate transaction.
117 static unsigned long blocks_for_truncate(struct inode *inode)
121 needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
123 /* Give ourselves just enough room to cope with inodes in which
124 * i_blocks is corrupt: we've seen disk corruptions in the past
125 * which resulted in random data in an inode which looked enough
126 * like a regular file for ext4 to try to delete it. Things
127 * will go a bit crazy if that happens, but at least we should
128 * try not to panic the whole kernel. */
132 /* But we need to bound the transaction so we don't overflow the
134 if (needed > EXT4_MAX_TRANS_DATA)
135 needed = EXT4_MAX_TRANS_DATA;
137 return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
141 * Truncate transactions can be complex and absolutely huge. So we need to
142 * be able to restart the transaction at a conventient checkpoint to make
143 * sure we don't overflow the journal.
145 * start_transaction gets us a new handle for a truncate transaction,
146 * and extend_transaction tries to extend the existing one a bit. If
147 * extend fails, we need to propagate the failure up and restart the
148 * transaction in the top-level truncate loop. --sct
150 static handle_t *start_transaction(struct inode *inode)
154 result = ext4_journal_start(inode, blocks_for_truncate(inode));
158 ext4_std_error(inode->i_sb, PTR_ERR(result));
163 * Try to extend this transaction for the purposes of truncation.
165 * Returns 0 if we managed to create more room. If we can't create more
166 * room, and the transaction must be restarted we return 1.
168 static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
170 if (handle->h_buffer_credits > EXT4_RESERVE_TRANS_BLOCKS)
172 if (!ext4_journal_extend(handle, blocks_for_truncate(inode)))
178 * Restart the transaction associated with *handle. This does a commit,
179 * so before we call here everything must be consistently dirtied against
182 static int ext4_journal_test_restart(handle_t *handle, struct inode *inode)
184 jbd_debug(2, "restarting handle %p\n", handle);
185 return ext4_journal_restart(handle, blocks_for_truncate(inode));
189 * Called at the last iput() if i_nlink is zero.
191 void ext4_delete_inode (struct inode * inode)
196 if (ext4_should_order_data(inode))
197 ext4_begin_ordered_truncate(inode, 0);
198 truncate_inode_pages(&inode->i_data, 0);
200 if (is_bad_inode(inode))
203 handle = ext4_journal_start(inode, blocks_for_truncate(inode)+3);
204 if (IS_ERR(handle)) {
205 ext4_std_error(inode->i_sb, PTR_ERR(handle));
207 * If we're going to skip the normal cleanup, we still need to
208 * make sure that the in-core orphan linked list is properly
211 ext4_orphan_del(NULL, inode);
218 err = ext4_mark_inode_dirty(handle, inode);
220 ext4_warning(inode->i_sb, __func__,
221 "couldn't mark inode dirty (err %d)", err);
225 ext4_truncate(inode);
228 * ext4_ext_truncate() doesn't reserve any slop when it
229 * restarts journal transactions; therefore there may not be
230 * enough credits left in the handle to remove the inode from
231 * the orphan list and set the dtime field.
233 if (handle->h_buffer_credits < 3) {
234 err = ext4_journal_extend(handle, 3);
236 err = ext4_journal_restart(handle, 3);
238 ext4_warning(inode->i_sb, __func__,
239 "couldn't extend journal (err %d)", err);
241 ext4_journal_stop(handle);
247 * Kill off the orphan record which ext4_truncate created.
248 * AKPM: I think this can be inside the above `if'.
249 * Note that ext4_orphan_del() has to be able to cope with the
250 * deletion of a non-existent orphan - this is because we don't
251 * know if ext4_truncate() actually created an orphan record.
252 * (Well, we could do this if we need to, but heck - it works)
254 ext4_orphan_del(handle, inode);
255 EXT4_I(inode)->i_dtime = get_seconds();
258 * One subtle ordering requirement: if anything has gone wrong
259 * (transaction abort, IO errors, whatever), then we can still
260 * do these next steps (the fs will already have been marked as
261 * having errors), but we can't free the inode if the mark_dirty
264 if (ext4_mark_inode_dirty(handle, inode))
265 /* If that failed, just do the required in-core inode clear. */
268 ext4_free_inode(handle, inode);
269 ext4_journal_stop(handle);
272 clear_inode(inode); /* We must guarantee clearing of inode... */
278 struct buffer_head *bh;
281 static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
283 p->key = *(p->p = v);
288 * ext4_block_to_path - parse the block number into array of offsets
289 * @inode: inode in question (we are only interested in its superblock)
290 * @i_block: block number to be parsed
291 * @offsets: array to store the offsets in
292 * @boundary: set this non-zero if the referred-to block is likely to be
293 * followed (on disk) by an indirect block.
295 * To store the locations of file's data ext4 uses a data structure common
296 * for UNIX filesystems - tree of pointers anchored in the inode, with
297 * data blocks at leaves and indirect blocks in intermediate nodes.
298 * This function translates the block number into path in that tree -
299 * return value is the path length and @offsets[n] is the offset of
300 * pointer to (n+1)th node in the nth one. If @block is out of range
301 * (negative or too large) warning is printed and zero returned.
303 * Note: function doesn't find node addresses, so no IO is needed. All
304 * we need to know is the capacity of indirect blocks (taken from the
309 * Portability note: the last comparison (check that we fit into triple
310 * indirect block) is spelled differently, because otherwise on an
311 * architecture with 32-bit longs and 8Kb pages we might get into trouble
312 * if our filesystem had 8Kb blocks. We might use long long, but that would
313 * kill us on x86. Oh, well, at least the sign propagation does not matter -
314 * i_block would have to be negative in the very beginning, so we would not
318 static int ext4_block_to_path(struct inode *inode,
320 ext4_lblk_t offsets[4], int *boundary)
322 int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb);
323 int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb);
324 const long direct_blocks = EXT4_NDIR_BLOCKS,
325 indirect_blocks = ptrs,
326 double_blocks = (1 << (ptrs_bits * 2));
331 ext4_warning (inode->i_sb, "ext4_block_to_path", "block < 0");
332 } else if (i_block < direct_blocks) {
333 offsets[n++] = i_block;
334 final = direct_blocks;
335 } else if ( (i_block -= direct_blocks) < indirect_blocks) {
336 offsets[n++] = EXT4_IND_BLOCK;
337 offsets[n++] = i_block;
339 } else if ((i_block -= indirect_blocks) < double_blocks) {
340 offsets[n++] = EXT4_DIND_BLOCK;
341 offsets[n++] = i_block >> ptrs_bits;
342 offsets[n++] = i_block & (ptrs - 1);
344 } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
345 offsets[n++] = EXT4_TIND_BLOCK;
346 offsets[n++] = i_block >> (ptrs_bits * 2);
347 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
348 offsets[n++] = i_block & (ptrs - 1);
351 ext4_warning(inode->i_sb, "ext4_block_to_path",
353 i_block + direct_blocks +
354 indirect_blocks + double_blocks);
357 *boundary = final - 1 - (i_block & (ptrs - 1));
362 * ext4_get_branch - read the chain of indirect blocks leading to data
363 * @inode: inode in question
364 * @depth: depth of the chain (1 - direct pointer, etc.)
365 * @offsets: offsets of pointers in inode/indirect blocks
366 * @chain: place to store the result
367 * @err: here we store the error value
369 * Function fills the array of triples <key, p, bh> and returns %NULL
370 * if everything went OK or the pointer to the last filled triple
371 * (incomplete one) otherwise. Upon the return chain[i].key contains
372 * the number of (i+1)-th block in the chain (as it is stored in memory,
373 * i.e. little-endian 32-bit), chain[i].p contains the address of that
374 * number (it points into struct inode for i==0 and into the bh->b_data
375 * for i>0) and chain[i].bh points to the buffer_head of i-th indirect
376 * block for i>0 and NULL for i==0. In other words, it holds the block
377 * numbers of the chain, addresses they were taken from (and where we can
378 * verify that chain did not change) and buffer_heads hosting these
381 * Function stops when it stumbles upon zero pointer (absent block)
382 * (pointer to last triple returned, *@err == 0)
383 * or when it gets an IO error reading an indirect block
384 * (ditto, *@err == -EIO)
385 * or when it reads all @depth-1 indirect blocks successfully and finds
386 * the whole chain, all way to the data (returns %NULL, *err == 0).
388 * Need to be called with
389 * down_read(&EXT4_I(inode)->i_data_sem)
391 static Indirect *ext4_get_branch(struct inode *inode, int depth,
392 ext4_lblk_t *offsets,
393 Indirect chain[4], int *err)
395 struct super_block *sb = inode->i_sb;
397 struct buffer_head *bh;
400 /* i_data is not going away, no lock needed */
401 add_chain (chain, NULL, EXT4_I(inode)->i_data + *offsets);
405 bh = sb_bread(sb, le32_to_cpu(p->key));
408 add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
422 * ext4_find_near - find a place for allocation with sufficient locality
424 * @ind: descriptor of indirect block.
426 * This function returns the preferred place for block allocation.
427 * It is used when heuristic for sequential allocation fails.
429 * + if there is a block to the left of our position - allocate near it.
430 * + if pointer will live in indirect block - allocate near that block.
431 * + if pointer will live in inode - allocate in the same
434 * In the latter case we colour the starting block by the callers PID to
435 * prevent it from clashing with concurrent allocations for a different inode
436 * in the same block group. The PID is used here so that functionally related
437 * files will be close-by on-disk.
439 * Caller must make sure that @ind is valid and will stay that way.
441 static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
443 struct ext4_inode_info *ei = EXT4_I(inode);
444 __le32 *start = ind->bh ? (__le32*) ind->bh->b_data : ei->i_data;
446 ext4_fsblk_t bg_start;
447 ext4_fsblk_t last_block;
448 ext4_grpblk_t colour;
450 /* Try to find previous block */
451 for (p = ind->p - 1; p >= start; p--) {
453 return le32_to_cpu(*p);
456 /* No such thing, so let's try location of indirect block */
458 return ind->bh->b_blocknr;
461 * It is going to be referred to from the inode itself? OK, just put it
462 * into the same cylinder group then.
464 bg_start = ext4_group_first_block_no(inode->i_sb, ei->i_block_group);
465 last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1;
467 if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block)
468 colour = (current->pid % 16) *
469 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
471 colour = (current->pid % 16) * ((last_block - bg_start) / 16);
472 return bg_start + colour;
476 * ext4_find_goal - find a preferred place for allocation.
478 * @block: block we want
479 * @partial: pointer to the last triple within a chain
481 * Normally this function find the preferred place for block allocation,
484 static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
487 struct ext4_block_alloc_info *block_i;
489 block_i = EXT4_I(inode)->i_block_alloc_info;
492 * try the heuristic for sequential allocation,
493 * failing that at least try to get decent locality.
495 if (block_i && (block == block_i->last_alloc_logical_block + 1)
496 && (block_i->last_alloc_physical_block != 0)) {
497 return block_i->last_alloc_physical_block + 1;
500 return ext4_find_near(inode, partial);
504 * ext4_blks_to_allocate: Look up the block map and count the number
505 * of direct blocks need to be allocated for the given branch.
507 * @branch: chain of indirect blocks
508 * @k: number of blocks need for indirect blocks
509 * @blks: number of data blocks to be mapped.
510 * @blocks_to_boundary: the offset in the indirect block
512 * return the total number of blocks to be allocate, including the
513 * direct and indirect blocks.
515 static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned long blks,
516 int blocks_to_boundary)
518 unsigned long count = 0;
521 * Simple case, [t,d]Indirect block(s) has not allocated yet
522 * then it's clear blocks on that path have not allocated
525 /* right now we don't handle cross boundary allocation */
526 if (blks < blocks_to_boundary + 1)
529 count += blocks_to_boundary + 1;
534 while (count < blks && count <= blocks_to_boundary &&
535 le32_to_cpu(*(branch[0].p + count)) == 0) {
542 * ext4_alloc_blocks: multiple allocate blocks needed for a branch
543 * @indirect_blks: the number of blocks need to allocate for indirect
546 * @new_blocks: on return it will store the new block numbers for
547 * the indirect blocks(if needed) and the first direct block,
548 * @blks: on return it will store the total number of allocated
551 static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
552 ext4_lblk_t iblock, ext4_fsblk_t goal,
553 int indirect_blks, int blks,
554 ext4_fsblk_t new_blocks[4], int *err)
557 unsigned long count = 0, blk_allocated = 0;
559 ext4_fsblk_t current_block = 0;
563 * Here we try to allocate the requested multiple blocks at once,
564 * on a best-effort basis.
565 * To build a branch, we should allocate blocks for
566 * the indirect blocks(if not allocated yet), and at least
567 * the first direct block of this branch. That's the
568 * minimum number of blocks need to allocate(required)
570 /* first we try to allocate the indirect blocks */
571 target = indirect_blks;
574 /* allocating blocks for indirect blocks and direct blocks */
575 current_block = ext4_new_meta_blocks(handle, inode,
581 /* allocate blocks for indirect blocks */
582 while (index < indirect_blks && count) {
583 new_blocks[index++] = current_block++;
588 * save the new block number
589 * for the first direct block
591 new_blocks[index] = current_block;
592 printk(KERN_INFO "%s returned more blocks than "
593 "requested\n", __func__);
599 target = blks - count ;
600 blk_allocated = count;
603 /* Now allocate data blocks */
605 /* allocating blocks for data blocks */
606 current_block = ext4_new_blocks(handle, inode, iblock,
608 if (*err && (target == blks)) {
610 * if the allocation failed and we didn't allocate
616 if (target == blks) {
618 * save the new block number
619 * for the first direct block
621 new_blocks[index] = current_block;
623 blk_allocated += count;
626 /* total number of blocks allocated for direct blocks */
631 for (i = 0; i <index; i++)
632 ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
637 * ext4_alloc_branch - allocate and set up a chain of blocks.
639 * @indirect_blks: number of allocated indirect blocks
640 * @blks: number of allocated direct blocks
641 * @offsets: offsets (in the blocks) to store the pointers to next.
642 * @branch: place to store the chain in.
644 * This function allocates blocks, zeroes out all but the last one,
645 * links them into chain and (if we are synchronous) writes them to disk.
646 * In other words, it prepares a branch that can be spliced onto the
647 * inode. It stores the information about that chain in the branch[], in
648 * the same format as ext4_get_branch() would do. We are calling it after
649 * we had read the existing part of chain and partial points to the last
650 * triple of that (one with zero ->key). Upon the exit we have the same
651 * picture as after the successful ext4_get_block(), except that in one
652 * place chain is disconnected - *branch->p is still zero (we did not
653 * set the last link), but branch->key contains the number that should
654 * be placed into *branch->p to fill that gap.
656 * If allocation fails we free all blocks we've allocated (and forget
657 * their buffer_heads) and return the error value the from failed
658 * ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
659 * as described above and return 0.
661 static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
662 ext4_lblk_t iblock, int indirect_blks,
663 int *blks, ext4_fsblk_t goal,
664 ext4_lblk_t *offsets, Indirect *branch)
666 int blocksize = inode->i_sb->s_blocksize;
669 struct buffer_head *bh;
671 ext4_fsblk_t new_blocks[4];
672 ext4_fsblk_t current_block;
674 num = ext4_alloc_blocks(handle, inode, iblock, goal, indirect_blks,
675 *blks, new_blocks, &err);
679 branch[0].key = cpu_to_le32(new_blocks[0]);
681 * metadata blocks and data blocks are allocated.
683 for (n = 1; n <= indirect_blks; n++) {
685 * Get buffer_head for parent block, zero it out
686 * and set the pointer to new one, then send
689 bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
692 BUFFER_TRACE(bh, "call get_create_access");
693 err = ext4_journal_get_create_access(handle, bh);
700 memset(bh->b_data, 0, blocksize);
701 branch[n].p = (__le32 *) bh->b_data + offsets[n];
702 branch[n].key = cpu_to_le32(new_blocks[n]);
703 *branch[n].p = branch[n].key;
704 if ( n == indirect_blks) {
705 current_block = new_blocks[n];
707 * End of chain, update the last new metablock of
708 * the chain to point to the new allocated
709 * data blocks numbers
711 for (i=1; i < num; i++)
712 *(branch[n].p + i) = cpu_to_le32(++current_block);
714 BUFFER_TRACE(bh, "marking uptodate");
715 set_buffer_uptodate(bh);
718 BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
719 err = ext4_journal_dirty_metadata(handle, bh);
726 /* Allocation failed, free what we already allocated */
727 for (i = 1; i <= n ; i++) {
728 BUFFER_TRACE(branch[i].bh, "call jbd2_journal_forget");
729 ext4_journal_forget(handle, branch[i].bh);
731 for (i = 0; i <indirect_blks; i++)
732 ext4_free_blocks(handle, inode, new_blocks[i], 1, 0);
734 ext4_free_blocks(handle, inode, new_blocks[i], num, 0);
740 * ext4_splice_branch - splice the allocated branch onto inode.
742 * @block: (logical) number of block we are adding
743 * @chain: chain of indirect blocks (with a missing link - see
745 * @where: location of missing link
746 * @num: number of indirect blocks we are adding
747 * @blks: number of direct blocks we are adding
749 * This function fills the missing link and does all housekeeping needed in
750 * inode (->i_blocks, etc.). In case of success we end up with the full
751 * chain to new block and return 0.
753 static int ext4_splice_branch(handle_t *handle, struct inode *inode,
754 ext4_lblk_t block, Indirect *where, int num, int blks)
758 struct ext4_block_alloc_info *block_i;
759 ext4_fsblk_t current_block;
761 block_i = EXT4_I(inode)->i_block_alloc_info;
763 * If we're splicing into a [td]indirect block (as opposed to the
764 * inode) then we need to get write access to the [td]indirect block
768 BUFFER_TRACE(where->bh, "get_write_access");
769 err = ext4_journal_get_write_access(handle, where->bh);
775 *where->p = where->key;
778 * Update the host buffer_head or inode to point to more just allocated
779 * direct blocks blocks
781 if (num == 0 && blks > 1) {
782 current_block = le32_to_cpu(where->key) + 1;
783 for (i = 1; i < blks; i++)
784 *(where->p + i ) = cpu_to_le32(current_block++);
788 * update the most recently allocated logical & physical block
789 * in i_block_alloc_info, to assist find the proper goal block for next
793 block_i->last_alloc_logical_block = block + blks - 1;
794 block_i->last_alloc_physical_block =
795 le32_to_cpu(where[num].key) + blks - 1;
798 /* We are done with atomic stuff, now do the rest of housekeeping */
800 inode->i_ctime = ext4_current_time(inode);
801 ext4_mark_inode_dirty(handle, inode);
803 /* had we spliced it onto indirect block? */
806 * If we spliced it onto an indirect block, we haven't
807 * altered the inode. Note however that if it is being spliced
808 * onto an indirect block at the very end of the file (the
809 * file is growing) then we *will* alter the inode to reflect
810 * the new i_size. But that is not done here - it is done in
811 * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
813 jbd_debug(5, "splicing indirect only\n");
814 BUFFER_TRACE(where->bh, "call ext4_journal_dirty_metadata");
815 err = ext4_journal_dirty_metadata(handle, where->bh);
820 * OK, we spliced it into the inode itself on a direct block.
821 * Inode was dirtied above.
823 jbd_debug(5, "splicing direct\n");
828 for (i = 1; i <= num; i++) {
829 BUFFER_TRACE(where[i].bh, "call jbd2_journal_forget");
830 ext4_journal_forget(handle, where[i].bh);
831 ext4_free_blocks(handle, inode,
832 le32_to_cpu(where[i-1].key), 1, 0);
834 ext4_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks, 0);
840 * Allocation strategy is simple: if we have to allocate something, we will
841 * have to go the whole way to leaf. So let's do it before attaching anything
842 * to tree, set linkage between the newborn blocks, write them if sync is
843 * required, recheck the path, free and repeat if check fails, otherwise
844 * set the last missing link (that will protect us from any truncate-generated
845 * removals - all blocks on the path are immune now) and possibly force the
846 * write on the parent block.
847 * That has a nice additional property: no special recovery from the failed
848 * allocations is needed - we simply release blocks and do not touch anything
849 * reachable from inode.
851 * `handle' can be NULL if create == 0.
853 * return > 0, # of blocks mapped or allocated.
854 * return = 0, if plain lookup failed.
855 * return < 0, error case.
858 * Need to be called with
859 * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block
860 * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem)
862 int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
863 ext4_lblk_t iblock, unsigned long maxblocks,
864 struct buffer_head *bh_result,
865 int create, int extend_disksize)
868 ext4_lblk_t offsets[4];
873 int blocks_to_boundary = 0;
875 struct ext4_inode_info *ei = EXT4_I(inode);
877 ext4_fsblk_t first_block = 0;
881 J_ASSERT(!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL));
882 J_ASSERT(handle != NULL || create == 0);
883 depth = ext4_block_to_path(inode, iblock, offsets,
884 &blocks_to_boundary);
889 partial = ext4_get_branch(inode, depth, offsets, chain, &err);
891 /* Simplest case - block found, no allocation needed */
893 first_block = le32_to_cpu(chain[depth - 1].key);
894 clear_buffer_new(bh_result);
897 while (count < maxblocks && count <= blocks_to_boundary) {
900 blk = le32_to_cpu(*(chain[depth-1].p + count));
902 if (blk == first_block + count)
910 /* Next simple case - plain lookup or failed read of indirect block */
911 if (!create || err == -EIO)
915 * Okay, we need to do block allocation. Lazily initialize the block
916 * allocation info here if necessary
918 if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
919 ext4_init_block_alloc_info(inode);
921 goal = ext4_find_goal(inode, iblock, partial);
923 /* the number of blocks need to allocate for [d,t]indirect blocks */
924 indirect_blks = (chain + depth) - partial - 1;
927 * Next look up the indirect map to count the totoal number of
928 * direct blocks to allocate for this branch.
930 count = ext4_blks_to_allocate(partial, indirect_blks,
931 maxblocks, blocks_to_boundary);
933 * Block out ext4_truncate while we alter the tree
935 err = ext4_alloc_branch(handle, inode, iblock, indirect_blks,
937 offsets + (partial - chain), partial);
940 * The ext4_splice_branch call will free and forget any buffers
941 * on the new chain if there is a failure, but that risks using
942 * up transaction credits, especially for bitmaps where the
943 * credits cannot be returned. Can we handle this somehow? We
944 * may need to return -EAGAIN upwards in the worst case. --sct
947 err = ext4_splice_branch(handle, inode, iblock,
948 partial, indirect_blks, count);
950 * i_disksize growing is protected by i_data_sem. Don't forget to
951 * protect it if you're about to implement concurrent
952 * ext4_get_block() -bzzz
954 if (!err && extend_disksize) {
955 disksize = ((loff_t) iblock + count) << inode->i_blkbits;
956 if (disksize > i_size_read(inode))
957 disksize = i_size_read(inode);
958 if (disksize > ei->i_disksize)
959 ei->i_disksize = disksize;
964 set_buffer_new(bh_result);
966 map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
967 if (count > blocks_to_boundary)
968 set_buffer_boundary(bh_result);
970 /* Clean up and exit */
971 partial = chain + depth - 1; /* the whole chain */
973 while (partial > chain) {
974 BUFFER_TRACE(partial->bh, "call brelse");
978 BUFFER_TRACE(bh_result, "returned");
983 /* Maximum number of blocks we map for direct IO at once. */
984 #define DIO_MAX_BLOCKS 4096
986 * Number of credits we need for writing DIO_MAX_BLOCKS:
987 * We need sb + group descriptor + bitmap + inode -> 4
988 * For B blocks with A block pointers per block we need:
989 * 1 (triple ind.) + (B/A/A + 2) (doubly ind.) + (B/A + 2) (indirect).
990 * If we plug in 4096 for B and 256 for A (for 1KB block size), we get 25.
992 #define DIO_CREDITS 25
998 * ext4_ext4 get_block() wrapper function
999 * It will do a look up first, and returns if the blocks already mapped.
1000 * Otherwise it takes the write lock of the i_data_sem and allocate blocks
1001 * and store the allocated blocks in the result buffer head and mark it
1004 * If file type is extents based, it will call ext4_ext_get_blocks(),
1005 * Otherwise, call with ext4_get_blocks_handle() to handle indirect mapping
1008 * On success, it returns the number of blocks being mapped or allocate.
1009 * if create==0 and the blocks are pre-allocated and uninitialized block,
1010 * the result buffer head is unmapped. If the create ==1, it will make sure
1011 * the buffer head is mapped.
1013 * It returns 0 if plain look up failed (blocks have not been allocated), in
1014 * that casem, buffer head is unmapped
1016 * It returns the error in case of allocation failure.
1018 int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
1019 unsigned long max_blocks, struct buffer_head *bh,
1020 int create, int extend_disksize, int flag)
1024 clear_buffer_mapped(bh);
1027 * Try to see if we can get the block without requesting
1028 * for new file system block.
1030 down_read((&EXT4_I(inode)->i_data_sem));
1031 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
1032 retval = ext4_ext_get_blocks(handle, inode, block, max_blocks,
1035 retval = ext4_get_blocks_handle(handle,
1036 inode, block, max_blocks, bh, 0, 0);
1038 up_read((&EXT4_I(inode)->i_data_sem));
1040 /* If it is only a block(s) look up */
1045 * Returns if the blocks have already allocated
1047 * Note that if blocks have been preallocated
1048 * ext4_ext_get_block() returns th create = 0
1049 * with buffer head unmapped.
1051 if (retval > 0 && buffer_mapped(bh))
1055 * New blocks allocate and/or writing to uninitialized extent
1056 * will possibly result in updating i_data, so we take
1057 * the write lock of i_data_sem, and call get_blocks()
1058 * with create == 1 flag.
1060 down_write((&EXT4_I(inode)->i_data_sem));
1063 * if the caller is from delayed allocation writeout path
1064 * we have already reserved fs blocks for allocation
1065 * let the underlying get_block() function know to
1066 * avoid double accounting
1069 EXT4_I(inode)->i_delalloc_reserved_flag = 1;
1071 * We need to check for EXT4 here because migrate
1072 * could have changed the inode type in between
1074 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
1075 retval = ext4_ext_get_blocks(handle, inode, block, max_blocks,
1076 bh, create, extend_disksize);
1078 retval = ext4_get_blocks_handle(handle, inode, block,
1079 max_blocks, bh, create, extend_disksize);
1081 if (retval > 0 && buffer_new(bh)) {
1083 * We allocated new blocks which will result in
1084 * i_data's format changing. Force the migrate
1085 * to fail by clearing migrate flags
1087 EXT4_I(inode)->i_flags = EXT4_I(inode)->i_flags &
1093 EXT4_I(inode)->i_delalloc_reserved_flag = 0;
1095 * Update reserved blocks/metadata blocks
1096 * after successful block allocation
1097 * which were deferred till now
1099 if ((retval > 0) && buffer_delay(bh))
1100 ext4_da_release_space(inode, retval, 0);
1103 up_write((&EXT4_I(inode)->i_data_sem));
1107 static int ext4_get_block(struct inode *inode, sector_t iblock,
1108 struct buffer_head *bh_result, int create)
1110 handle_t *handle = ext4_journal_current_handle();
1111 int ret = 0, started = 0;
1112 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
1114 if (create && !handle) {
1115 /* Direct IO write... */
1116 if (max_blocks > DIO_MAX_BLOCKS)
1117 max_blocks = DIO_MAX_BLOCKS;
1118 handle = ext4_journal_start(inode, DIO_CREDITS +
1119 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb));
1120 if (IS_ERR(handle)) {
1121 ret = PTR_ERR(handle);
1127 ret = ext4_get_blocks_wrap(handle, inode, iblock,
1128 max_blocks, bh_result, create, 0, 0);
1130 bh_result->b_size = (ret << inode->i_blkbits);
1134 ext4_journal_stop(handle);
1140 * `handle' can be NULL if create is zero
1142 struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
1143 ext4_lblk_t block, int create, int *errp)
1145 struct buffer_head dummy;
1148 J_ASSERT(handle != NULL || create == 0);
1151 dummy.b_blocknr = -1000;
1152 buffer_trace_init(&dummy.b_history);
1153 err = ext4_get_blocks_wrap(handle, inode, block, 1,
1154 &dummy, create, 1, 0);
1156 * ext4_get_blocks_handle() returns number of blocks
1157 * mapped. 0 in case of a HOLE.
1165 if (!err && buffer_mapped(&dummy)) {
1166 struct buffer_head *bh;
1167 bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
1172 if (buffer_new(&dummy)) {
1173 J_ASSERT(create != 0);
1174 J_ASSERT(handle != NULL);
1177 * Now that we do not always journal data, we should
1178 * keep in mind whether this should always journal the
1179 * new buffer as metadata. For now, regular file
1180 * writes use ext4_get_block instead, so it's not a
1184 BUFFER_TRACE(bh, "call get_create_access");
1185 fatal = ext4_journal_get_create_access(handle, bh);
1186 if (!fatal && !buffer_uptodate(bh)) {
1187 memset(bh->b_data,0,inode->i_sb->s_blocksize);
1188 set_buffer_uptodate(bh);
1191 BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
1192 err = ext4_journal_dirty_metadata(handle, bh);
1196 BUFFER_TRACE(bh, "not a new buffer");
1209 struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
1210 ext4_lblk_t block, int create, int *err)
1212 struct buffer_head * bh;
1214 bh = ext4_getblk(handle, inode, block, create, err);
1217 if (buffer_uptodate(bh))
1219 ll_rw_block(READ_META, 1, &bh);
1221 if (buffer_uptodate(bh))
1228 static int walk_page_buffers( handle_t *handle,
1229 struct buffer_head *head,
1233 int (*fn)( handle_t *handle,
1234 struct buffer_head *bh))
1236 struct buffer_head *bh;
1237 unsigned block_start, block_end;
1238 unsigned blocksize = head->b_size;
1240 struct buffer_head *next;
1242 for ( bh = head, block_start = 0;
1243 ret == 0 && (bh != head || !block_start);
1244 block_start = block_end, bh = next)
1246 next = bh->b_this_page;
1247 block_end = block_start + blocksize;
1248 if (block_end <= from || block_start >= to) {
1249 if (partial && !buffer_uptodate(bh))
1253 err = (*fn)(handle, bh);
1261 * To preserve ordering, it is essential that the hole instantiation and
1262 * the data write be encapsulated in a single transaction. We cannot
1263 * close off a transaction and start a new one between the ext4_get_block()
1264 * and the commit_write(). So doing the jbd2_journal_start at the start of
1265 * prepare_write() is the right place.
1267 * Also, this function can nest inside ext4_writepage() ->
1268 * block_write_full_page(). In that case, we *know* that ext4_writepage()
1269 * has generated enough buffer credits to do the whole page. So we won't
1270 * block on the journal in that case, which is good, because the caller may
1273 * By accident, ext4 can be reentered when a transaction is open via
1274 * quota file writes. If we were to commit the transaction while thus
1275 * reentered, there can be a deadlock - we would be holding a quota
1276 * lock, and the commit would never complete if another thread had a
1277 * transaction open and was blocking on the quota lock - a ranking
1280 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
1281 * will _not_ run commit under these circumstances because handle->h_ref
1282 * is elevated. We'll still have enough credits for the tiny quotafile
1285 static int do_journal_get_write_access(handle_t *handle,
1286 struct buffer_head *bh)
1288 if (!buffer_mapped(bh) || buffer_freed(bh))
1290 return ext4_journal_get_write_access(handle, bh);
1293 static int ext4_write_begin(struct file *file, struct address_space *mapping,
1294 loff_t pos, unsigned len, unsigned flags,
1295 struct page **pagep, void **fsdata)
1297 struct inode *inode = mapping->host;
1298 int ret, needed_blocks = ext4_writepage_trans_blocks(inode);
1305 index = pos >> PAGE_CACHE_SHIFT;
1306 from = pos & (PAGE_CACHE_SIZE - 1);
1310 handle = ext4_journal_start(inode, needed_blocks);
1311 if (IS_ERR(handle)) {
1312 ret = PTR_ERR(handle);
1316 page = __grab_cache_page(mapping, index);
1318 ext4_journal_stop(handle);
1324 ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
1327 if (!ret && ext4_should_journal_data(inode)) {
1328 ret = walk_page_buffers(handle, page_buffers(page),
1329 from, to, NULL, do_journal_get_write_access);
1334 ext4_journal_stop(handle);
1335 page_cache_release(page);
1338 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
1344 /* For write_end() in data=journal mode */
1345 static int write_end_fn(handle_t *handle, struct buffer_head *bh)
1347 if (!buffer_mapped(bh) || buffer_freed(bh))
1349 set_buffer_uptodate(bh);
1350 return ext4_journal_dirty_metadata(handle, bh);
1354 * We need to pick up the new inode size which generic_commit_write gave us
1355 * `file' can be NULL - eg, when called from page_symlink().
1357 * ext4 never places buffers on inode->i_mapping->private_list. metadata
1358 * buffers are managed internally.
1360 static int ext4_ordered_write_end(struct file *file,
1361 struct address_space *mapping,
1362 loff_t pos, unsigned len, unsigned copied,
1363 struct page *page, void *fsdata)
1365 handle_t *handle = ext4_journal_current_handle();
1366 struct inode *inode = mapping->host;
1370 from = pos & (PAGE_CACHE_SIZE - 1);
1373 ret = ext4_jbd2_file_inode(handle, inode);
1377 * generic_write_end() will run mark_inode_dirty() if i_size
1378 * changes. So let's piggyback the i_disksize mark_inode_dirty
1383 new_i_size = pos + copied;
1384 if (new_i_size > EXT4_I(inode)->i_disksize)
1385 EXT4_I(inode)->i_disksize = new_i_size;
1386 ret2 = generic_write_end(file, mapping, pos, len, copied,
1392 ret2 = ext4_journal_stop(handle);
1396 return ret ? ret : copied;
1399 static int ext4_writeback_write_end(struct file *file,
1400 struct address_space *mapping,
1401 loff_t pos, unsigned len, unsigned copied,
1402 struct page *page, void *fsdata)
1404 handle_t *handle = ext4_journal_current_handle();
1405 struct inode *inode = mapping->host;
1409 new_i_size = pos + copied;
1410 if (new_i_size > EXT4_I(inode)->i_disksize)
1411 EXT4_I(inode)->i_disksize = new_i_size;
1413 ret2 = generic_write_end(file, mapping, pos, len, copied,
1419 ret2 = ext4_journal_stop(handle);
1423 return ret ? ret : copied;
1426 static int ext4_journalled_write_end(struct file *file,
1427 struct address_space *mapping,
1428 loff_t pos, unsigned len, unsigned copied,
1429 struct page *page, void *fsdata)
1431 handle_t *handle = ext4_journal_current_handle();
1432 struct inode *inode = mapping->host;
1437 from = pos & (PAGE_CACHE_SIZE - 1);
1441 if (!PageUptodate(page))
1443 page_zero_new_buffers(page, from+copied, to);
1446 ret = walk_page_buffers(handle, page_buffers(page), from,
1447 to, &partial, write_end_fn);
1449 SetPageUptodate(page);
1450 if (pos+copied > inode->i_size)
1451 i_size_write(inode, pos+copied);
1452 EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
1453 if (inode->i_size > EXT4_I(inode)->i_disksize) {
1454 EXT4_I(inode)->i_disksize = inode->i_size;
1455 ret2 = ext4_mark_inode_dirty(handle, inode);
1461 ret2 = ext4_journal_stop(handle);
1464 page_cache_release(page);
1466 return ret ? ret : copied;
1469 * Calculate the number of metadata blocks need to reserve
1470 * to allocate @blocks for non extent file based file
1472 static int ext4_indirect_calc_metadata_amount(struct inode *inode, int blocks)
1474 int icap = EXT4_ADDR_PER_BLOCK(inode->i_sb);
1475 int ind_blks, dind_blks, tind_blks;
1477 /* number of new indirect blocks needed */
1478 ind_blks = (blocks + icap - 1) / icap;
1480 dind_blks = (ind_blks + icap - 1) / icap;
1484 return ind_blks + dind_blks + tind_blks;
1488 * Calculate the number of metadata blocks need to reserve
1489 * to allocate given number of blocks
1491 static int ext4_calc_metadata_amount(struct inode *inode, int blocks)
1493 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
1494 return ext4_ext_calc_metadata_amount(inode, blocks);
1496 return ext4_indirect_calc_metadata_amount(inode, blocks);
1499 static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
1501 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1502 unsigned long md_needed, mdblocks, total = 0;
1505 * recalculate the amount of metadata blocks to reserve
1506 * in order to allocate nrblocks
1507 * worse case is one extent per block
1509 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1510 total = EXT4_I(inode)->i_reserved_data_blocks + nrblocks;
1511 mdblocks = ext4_calc_metadata_amount(inode, total);
1512 BUG_ON(mdblocks < EXT4_I(inode)->i_reserved_meta_blocks);
1514 md_needed = mdblocks - EXT4_I(inode)->i_reserved_meta_blocks;
1515 total = md_needed + nrblocks;
1517 if (ext4_has_free_blocks(sbi, total) < total) {
1518 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1522 /* reduce fs free blocks counter */
1523 percpu_counter_sub(&sbi->s_freeblocks_counter, total);
1525 EXT4_I(inode)->i_reserved_data_blocks += nrblocks;
1526 EXT4_I(inode)->i_reserved_meta_blocks = mdblocks;
1528 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1529 return 0; /* success */
1532 void ext4_da_release_space(struct inode *inode, int used, int to_free)
1534 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1535 int total, mdb, mdb_free, release;
1537 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
1538 /* recalculate the number of metablocks still need to be reserved */
1539 total = EXT4_I(inode)->i_reserved_data_blocks - used - to_free;
1540 mdb = ext4_calc_metadata_amount(inode, total);
1542 /* figure out how many metablocks to release */
1543 BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
1544 mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;
1546 /* Account for allocated meta_blocks */
1547 mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks;
1549 release = to_free + mdb_free;
1551 /* update fs free blocks counter for truncate case */
1552 percpu_counter_add(&sbi->s_freeblocks_counter, release);
1554 /* update per-inode reservations */
1555 BUG_ON(used + to_free > EXT4_I(inode)->i_reserved_data_blocks);
1556 EXT4_I(inode)->i_reserved_data_blocks -= (used + to_free);
1558 BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
1559 EXT4_I(inode)->i_reserved_meta_blocks = mdb;
1560 EXT4_I(inode)->i_allocated_meta_blocks = 0;
1561 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
1564 static void ext4_da_page_release_reservation(struct page *page,
1565 unsigned long offset)
1568 struct buffer_head *head, *bh;
1569 unsigned int curr_off = 0;
1571 head = page_buffers(page);
1574 unsigned int next_off = curr_off + bh->b_size;
1576 if ((offset <= curr_off) && (buffer_delay(bh))) {
1578 clear_buffer_delay(bh);
1580 curr_off = next_off;
1581 } while ((bh = bh->b_this_page) != head);
1582 ext4_da_release_space(page->mapping->host, 0, to_release);
1586 * Delayed allocation stuff
1589 struct mpage_da_data {
1590 struct inode *inode;
1591 struct buffer_head lbh; /* extent of blocks */
1592 unsigned long first_page, next_page; /* extent of pages */
1593 get_block_t *get_block;
1594 struct writeback_control *wbc;
1598 * mpage_da_submit_io - walks through extent of pages and try to write
1599 * them with __mpage_writepage()
1601 * @mpd->inode: inode
1602 * @mpd->first_page: first page of the extent
1603 * @mpd->next_page: page after the last page of the extent
1604 * @mpd->get_block: the filesystem's block mapper function
1606 * By the time mpage_da_submit_io() is called we expect all blocks
1607 * to be allocated. this may be wrong if allocation failed.
1609 * As pages are already locked by write_cache_pages(), we can't use it
1611 static int mpage_da_submit_io(struct mpage_da_data *mpd)
1613 struct address_space *mapping = mpd->inode->i_mapping;
1614 struct mpage_data mpd_pp = {
1616 .last_block_in_bio = 0,
1617 .get_block = mpd->get_block,
1620 int ret = 0, err, nr_pages, i;
1621 unsigned long index, end;
1622 struct pagevec pvec;
1624 BUG_ON(mpd->next_page <= mpd->first_page);
1626 pagevec_init(&pvec, 0);
1627 index = mpd->first_page;
1628 end = mpd->next_page - 1;
1630 while (index <= end) {
1631 /* XXX: optimize tail */
1632 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
1635 for (i = 0; i < nr_pages; i++) {
1636 struct page *page = pvec.pages[i];
1638 index = page->index;
1643 err = __mpage_writepage(page, mpd->wbc, &mpd_pp);
1646 * In error case, we have to continue because
1647 * remaining pages are still locked
1648 * XXX: unlock and re-dirty them?
1653 pagevec_release(&pvec);
1656 mpage_bio_submit(WRITE, mpd_pp.bio);
1662 * mpage_put_bnr_to_bhs - walk blocks and assign them actual numbers
1664 * @mpd->inode - inode to walk through
1665 * @exbh->b_blocknr - first block on a disk
1666 * @exbh->b_size - amount of space in bytes
1667 * @logical - first logical block to start assignment with
1669 * the function goes through all passed space and put actual disk
1670 * block numbers into buffer heads, dropping BH_Delay
1672 static void mpage_put_bnr_to_bhs(struct mpage_da_data *mpd, sector_t logical,
1673 struct buffer_head *exbh)
1675 struct inode *inode = mpd->inode;
1676 struct address_space *mapping = inode->i_mapping;
1677 int blocks = exbh->b_size >> inode->i_blkbits;
1678 sector_t pblock = exbh->b_blocknr, cur_logical;
1679 struct buffer_head *head, *bh;
1680 unsigned long index, end;
1681 struct pagevec pvec;
1684 index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
1685 end = (logical + blocks - 1) >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
1686 cur_logical = index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
1688 pagevec_init(&pvec, 0);
1690 while (index <= end) {
1691 /* XXX: optimize tail */
1692 nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
1695 for (i = 0; i < nr_pages; i++) {
1696 struct page *page = pvec.pages[i];
1698 index = page->index;
1703 BUG_ON(!PageLocked(page));
1704 BUG_ON(PageWriteback(page));
1705 BUG_ON(!page_has_buffers(page));
1707 bh = page_buffers(page);
1710 /* skip blocks out of the range */
1712 if (cur_logical >= logical)
1715 } while ((bh = bh->b_this_page) != head);
1718 if (cur_logical >= logical + blocks)
1720 if (buffer_delay(bh)) {
1721 bh->b_blocknr = pblock;
1722 clear_buffer_delay(bh);
1723 } else if (buffer_mapped(bh))
1724 BUG_ON(bh->b_blocknr != pblock);
1728 } while ((bh = bh->b_this_page) != head);
1730 pagevec_release(&pvec);
1736 * __unmap_underlying_blocks - just a helper function to unmap
1737 * set of blocks described by @bh
1739 static inline void __unmap_underlying_blocks(struct inode *inode,
1740 struct buffer_head *bh)
1742 struct block_device *bdev = inode->i_sb->s_bdev;
1745 blocks = bh->b_size >> inode->i_blkbits;
1746 for (i = 0; i < blocks; i++)
1747 unmap_underlying_metadata(bdev, bh->b_blocknr + i);
1751 * mpage_da_map_blocks - go through given space
1753 * @mpd->lbh - bh describing space
1754 * @mpd->get_block - the filesystem's block mapper function
1756 * The function skips space we know is already mapped to disk blocks.
1758 * The function ignores errors ->get_block() returns, thus real
1759 * error handling is postponed to __mpage_writepage()
1761 static void mpage_da_map_blocks(struct mpage_da_data *mpd)
1763 struct buffer_head *lbh = &mpd->lbh;
1764 int err = 0, remain = lbh->b_size;
1765 sector_t next = lbh->b_blocknr;
1766 struct buffer_head new;
1769 * We consider only non-mapped and non-allocated blocks
1771 if (buffer_mapped(lbh) && !buffer_delay(lbh))
1775 new.b_state = lbh->b_state;
1777 new.b_size = remain;
1778 err = mpd->get_block(mpd->inode, next, &new, 1);
1781 * Rather than implement own error handling
1782 * here, we just leave remaining blocks
1783 * unallocated and try again with ->writepage()
1787 BUG_ON(new.b_size == 0);
1789 if (buffer_new(&new))
1790 __unmap_underlying_blocks(mpd->inode, &new);
1793 * If blocks are delayed marked, we need to
1794 * put actual blocknr and drop delayed bit
1796 if (buffer_delay(lbh))
1797 mpage_put_bnr_to_bhs(mpd, next, &new);
1799 /* go for the remaining blocks */
1800 next += new.b_size >> mpd->inode->i_blkbits;
1801 remain -= new.b_size;
1805 #define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | (1 << BH_Delay))
1808 * mpage_add_bh_to_extent - try to add one more block to extent of blocks
1810 * @mpd->lbh - extent of blocks
1811 * @logical - logical number of the block in the file
1812 * @bh - bh of the block (used to access block's state)
1814 * the function is used to collect contig. blocks in same state
1816 static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
1817 sector_t logical, struct buffer_head *bh)
1819 struct buffer_head *lbh = &mpd->lbh;
1822 next = lbh->b_blocknr + (lbh->b_size >> mpd->inode->i_blkbits);
1825 * First block in the extent
1827 if (lbh->b_size == 0) {
1828 lbh->b_blocknr = logical;
1829 lbh->b_size = bh->b_size;
1830 lbh->b_state = bh->b_state & BH_FLAGS;
1835 * Can we merge the block to our big extent?
1837 if (logical == next && (bh->b_state & BH_FLAGS) == lbh->b_state) {
1838 lbh->b_size += bh->b_size;
1843 * We couldn't merge the block to our extent, so we
1844 * need to flush current extent and start new one
1846 mpage_da_map_blocks(mpd);
1849 * Now start a new extent
1851 lbh->b_size = bh->b_size;
1852 lbh->b_state = bh->b_state & BH_FLAGS;
1853 lbh->b_blocknr = logical;
1857 * __mpage_da_writepage - finds extent of pages and blocks
1859 * @page: page to consider
1860 * @wbc: not used, we just follow rules
1863 * The function finds extents of pages and scan them for all blocks.
1865 static int __mpage_da_writepage(struct page *page,
1866 struct writeback_control *wbc, void *data)
1868 struct mpage_da_data *mpd = data;
1869 struct inode *inode = mpd->inode;
1870 struct buffer_head *bh, *head, fake;
1874 * Can we merge this page to current extent?
1876 if (mpd->next_page != page->index) {
1878 * Nope, we can't. So, we map non-allocated blocks
1879 * and start IO on them using __mpage_writepage()
1881 if (mpd->next_page != mpd->first_page) {
1882 mpage_da_map_blocks(mpd);
1883 mpage_da_submit_io(mpd);
1887 * Start next extent of pages ...
1889 mpd->first_page = page->index;
1894 mpd->lbh.b_size = 0;
1895 mpd->lbh.b_state = 0;
1896 mpd->lbh.b_blocknr = 0;
1899 mpd->next_page = page->index + 1;
1900 logical = (sector_t) page->index <<
1901 (PAGE_CACHE_SHIFT - inode->i_blkbits);
1903 if (!page_has_buffers(page)) {
1905 * There is no attached buffer heads yet (mmap?)
1906 * we treat the page asfull of dirty blocks
1909 bh->b_size = PAGE_CACHE_SIZE;
1911 set_buffer_dirty(bh);
1912 set_buffer_uptodate(bh);
1913 mpage_add_bh_to_extent(mpd, logical, bh);
1916 * Page with regular buffer heads, just add all dirty ones
1918 head = page_buffers(page);
1921 BUG_ON(buffer_locked(bh));
1922 if (buffer_dirty(bh))
1923 mpage_add_bh_to_extent(mpd, logical, bh);
1925 } while ((bh = bh->b_this_page) != head);
1932 * mpage_da_writepages - walk the list of dirty pages of the given
1933 * address space, allocates non-allocated blocks, maps newly-allocated
1934 * blocks to existing bhs and issue IO them
1936 * @mapping: address space structure to write
1937 * @wbc: subtract the number of written pages from *@wbc->nr_to_write
1938 * @get_block: the filesystem's block mapper function.
1940 * This is a library function, which implements the writepages()
1941 * address_space_operation.
1943 * In order to avoid duplication of logic that deals with partial pages,
1944 * multiple bio per page, etc, we find non-allocated blocks, allocate
1945 * them with minimal calls to ->get_block() and re-use __mpage_writepage()
1947 * It's important that we call __mpage_writepage() only once for each
1948 * involved page, otherwise we'd have to implement more complicated logic
1949 * to deal with pages w/o PG_lock or w/ PG_writeback and so on.
1951 * See comments to mpage_writepages()
1953 static int mpage_da_writepages(struct address_space *mapping,
1954 struct writeback_control *wbc,
1955 get_block_t get_block)
1957 struct mpage_da_data mpd;
1961 return generic_writepages(mapping, wbc);
1964 mpd.inode = mapping->host;
1966 mpd.lbh.b_state = 0;
1967 mpd.lbh.b_blocknr = 0;
1970 mpd.get_block = get_block;
1972 ret = write_cache_pages(mapping, wbc, __mpage_da_writepage, &mpd);
1975 * Handle last extent of pages
1977 if (mpd.next_page != mpd.first_page) {
1978 mpage_da_map_blocks(&mpd);
1979 mpage_da_submit_io(&mpd);
1986 * this is a special callback for ->write_begin() only
1987 * it's intention is to return mapped block or reserve space
1989 static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
1990 struct buffer_head *bh_result, int create)
1994 BUG_ON(create == 0);
1995 BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
1998 * first, we need to know whether the block is allocated already
1999 * preallocated blocks are unmapped but should treated
2000 * the same as allocated blocks.
2002 ret = ext4_get_blocks_wrap(NULL, inode, iblock, 1, bh_result, 0, 0, 0);
2003 if ((ret == 0) && !buffer_delay(bh_result)) {
2004 /* the block isn't (pre)allocated yet, let's reserve space */
2006 * XXX: __block_prepare_write() unmaps passed block,
2009 ret = ext4_da_reserve_space(inode, 1);
2011 /* not enough space to reserve */
2014 map_bh(bh_result, inode->i_sb, 0);
2015 set_buffer_new(bh_result);
2016 set_buffer_delay(bh_result);
2017 } else if (ret > 0) {
2018 bh_result->b_size = (ret << inode->i_blkbits);
2024 #define EXT4_DELALLOC_RSVED 1
2025 static int ext4_da_get_block_write(struct inode *inode, sector_t iblock,
2026 struct buffer_head *bh_result, int create)
2029 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
2030 loff_t disksize = EXT4_I(inode)->i_disksize;
2031 handle_t *handle = NULL;
2033 handle = ext4_journal_current_handle();
2035 ret = ext4_get_blocks_wrap(handle, inode, iblock, max_blocks,
2036 bh_result, 0, 0, 0);
2039 ret = ext4_get_blocks_wrap(handle, inode, iblock, max_blocks,
2040 bh_result, create, 0, EXT4_DELALLOC_RSVED);
2044 bh_result->b_size = (ret << inode->i_blkbits);
2047 * Update on-disk size along with block allocation
2048 * we don't use 'extend_disksize' as size may change
2049 * within already allocated block -bzzz
2051 disksize = ((loff_t) iblock + ret) << inode->i_blkbits;
2052 if (disksize > i_size_read(inode))
2053 disksize = i_size_read(inode);
2054 if (disksize > EXT4_I(inode)->i_disksize) {
2056 * XXX: replace with spinlock if seen contended -bzzz
2058 down_write(&EXT4_I(inode)->i_data_sem);
2059 if (disksize > EXT4_I(inode)->i_disksize)
2060 EXT4_I(inode)->i_disksize = disksize;
2061 up_write(&EXT4_I(inode)->i_data_sem);
2063 if (EXT4_I(inode)->i_disksize == disksize) {
2064 ret = ext4_mark_inode_dirty(handle, inode);
2073 static int ext4_bh_unmapped_or_delay(handle_t *handle, struct buffer_head *bh)
2076 * unmapped buffer is possible for holes.
2077 * delay buffer is possible with delayed allocation
2079 return ((!buffer_mapped(bh) || buffer_delay(bh)) && buffer_dirty(bh));
2082 static int ext4_normal_get_block_write(struct inode *inode, sector_t iblock,
2083 struct buffer_head *bh_result, int create)
2086 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
2089 * we don't want to do block allocation in writepage
2090 * so call get_block_wrap with create = 0
2092 ret = ext4_get_blocks_wrap(NULL, inode, iblock, max_blocks,
2093 bh_result, 0, 0, 0);
2095 bh_result->b_size = (ret << inode->i_blkbits);
2102 * get called vi ext4_da_writepages after taking page lock (have journal handle)
2103 * get called via journal_submit_inode_data_buffers (no journal handle)
2104 * get called via shrink_page_list via pdflush (no journal handle)
2105 * or grab_page_cache when doing write_begin (have journal handle)
2107 static int ext4_da_writepage(struct page *page,
2108 struct writeback_control *wbc)
2113 struct buffer_head *page_bufs;
2114 struct inode *inode = page->mapping->host;
2116 size = i_size_read(inode);
2117 if (page->index == size >> PAGE_CACHE_SHIFT)
2118 len = size & ~PAGE_CACHE_MASK;
2120 len = PAGE_CACHE_SIZE;
2122 if (page_has_buffers(page)) {
2123 page_bufs = page_buffers(page);
2124 if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
2125 ext4_bh_unmapped_or_delay)) {
2127 * We don't want to do block allocation
2128 * So redirty the page and return
2129 * We may reach here when we do a journal commit
2130 * via journal_submit_inode_data_buffers.
2131 * If we don't have mapping block we just ignore
2132 * them. We can also reach here via shrink_page_list
2134 redirty_page_for_writepage(wbc, page);
2140 * The test for page_has_buffers() is subtle:
2141 * We know the page is dirty but it lost buffers. That means
2142 * that at some moment in time after write_begin()/write_end()
2143 * has been called all buffers have been clean and thus they
2144 * must have been written at least once. So they are all
2145 * mapped and we can happily proceed with mapping them
2146 * and writing the page.
2148 * Try to initialize the buffer_heads and check whether
2149 * all are mapped and non delay. We don't want to
2150 * do block allocation here.
2152 ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
2153 ext4_normal_get_block_write);
2155 page_bufs = page_buffers(page);
2156 /* check whether all are mapped and non delay */
2157 if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
2158 ext4_bh_unmapped_or_delay)) {
2159 redirty_page_for_writepage(wbc, page);
2165 * We can't do block allocation here
2166 * so just redity the page and unlock
2169 redirty_page_for_writepage(wbc, page);
2175 if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
2176 ret = nobh_writepage(page, ext4_normal_get_block_write, wbc);
2178 ret = block_write_full_page(page,
2179 ext4_normal_get_block_write,
2186 * For now just follow the DIO way to estimate the max credits
2187 * needed to write out EXT4_MAX_WRITEBACK_PAGES.
2188 * todo: need to calculate the max credits need for
2189 * extent based files, currently the DIO credits is based on
2190 * indirect-blocks mapping way.
2192 * Probably should have a generic way to calculate credits
2193 * for DIO, writepages, and truncate
2195 #define EXT4_MAX_WRITEBACK_PAGES DIO_MAX_BLOCKS
2196 #define EXT4_MAX_WRITEBACK_CREDITS DIO_CREDITS
2198 static int ext4_da_writepages(struct address_space *mapping,
2199 struct writeback_control *wbc)
2201 struct inode *inode = mapping->host;
2202 handle_t *handle = NULL;
2206 loff_t range_start = 0;
2209 * No pages to write? This is mainly a kludge to avoid starting
2210 * a transaction for special inodes like journal inode on last iput()
2211 * because that could violate lock ordering on umount
2213 if (!mapping->nrpages)
2217 * Estimate the worse case needed credits to write out
2218 * EXT4_MAX_BUF_BLOCKS pages
2220 needed_blocks = EXT4_MAX_WRITEBACK_CREDITS;
2222 to_write = wbc->nr_to_write;
2223 if (!wbc->range_cyclic) {
2225 * If range_cyclic is not set force range_cont
2226 * and save the old writeback_index
2228 wbc->range_cont = 1;
2229 range_start = wbc->range_start;
2232 while (!ret && to_write) {
2233 /* start a new transaction*/
2234 handle = ext4_journal_start(inode, needed_blocks);
2235 if (IS_ERR(handle)) {
2236 ret = PTR_ERR(handle);
2237 goto out_writepages;
2239 if (ext4_should_order_data(inode)) {
2241 * With ordered mode we need to add
2242 * the inode to the journal handle
2243 * when we do block allocation.
2245 ret = ext4_jbd2_file_inode(handle, inode);
2247 ext4_journal_stop(handle);
2248 goto out_writepages;
2253 * set the max dirty pages could be write at a time
2254 * to fit into the reserved transaction credits
2256 if (wbc->nr_to_write > EXT4_MAX_WRITEBACK_PAGES)
2257 wbc->nr_to_write = EXT4_MAX_WRITEBACK_PAGES;
2259 to_write -= wbc->nr_to_write;
2260 ret = mpage_da_writepages(mapping, wbc,
2261 ext4_da_get_block_write);
2262 ext4_journal_stop(handle);
2263 if (wbc->nr_to_write) {
2265 * There is no more writeout needed
2266 * or we requested for a noblocking writeout
2267 * and we found the device congested
2269 to_write += wbc->nr_to_write;
2272 wbc->nr_to_write = to_write;
2276 wbc->nr_to_write = to_write;
2278 wbc->range_start = range_start;
2282 static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
2283 loff_t pos, unsigned len, unsigned flags,
2284 struct page **pagep, void **fsdata)
2286 int ret, retries = 0;
2290 struct inode *inode = mapping->host;
2293 index = pos >> PAGE_CACHE_SHIFT;
2294 from = pos & (PAGE_CACHE_SIZE - 1);
2299 * With delayed allocation, we don't log the i_disksize update
2300 * if there is delayed block allocation. But we still need
2301 * to journalling the i_disksize update if writes to the end
2302 * of file which has an already mapped buffer.
2304 handle = ext4_journal_start(inode, 1);
2305 if (IS_ERR(handle)) {
2306 ret = PTR_ERR(handle);
2310 page = __grab_cache_page(mapping, index);
2312 ext4_journal_stop(handle);
2318 ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
2319 ext4_da_get_block_prep);
2322 ext4_journal_stop(handle);
2323 page_cache_release(page);
2326 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
2333 * Check if we should update i_disksize
2334 * when write to the end of file but not require block allocation
2336 static int ext4_da_should_update_i_disksize(struct page *page,
2337 unsigned long offset)
2339 struct buffer_head *bh;
2340 struct inode *inode = page->mapping->host;
2344 bh = page_buffers(page);
2345 idx = offset >> inode->i_blkbits;
2347 for (i=0; i < idx; i++)
2348 bh = bh->b_this_page;
2350 if (!buffer_mapped(bh) || (buffer_delay(bh)))
2355 static int ext4_da_write_end(struct file *file,
2356 struct address_space *mapping,
2357 loff_t pos, unsigned len, unsigned copied,
2358 struct page *page, void *fsdata)
2360 struct inode *inode = mapping->host;
2362 handle_t *handle = ext4_journal_current_handle();
2364 unsigned long start, end;
2366 start = pos & (PAGE_CACHE_SIZE - 1);
2367 end = start + copied -1;
2370 * generic_write_end() will run mark_inode_dirty() if i_size
2371 * changes. So let's piggyback the i_disksize mark_inode_dirty
2375 new_i_size = pos + copied;
2376 if (new_i_size > EXT4_I(inode)->i_disksize) {
2377 if (ext4_da_should_update_i_disksize(page, end)) {
2378 down_write(&EXT4_I(inode)->i_data_sem);
2379 if (new_i_size > EXT4_I(inode)->i_disksize) {
2381 * Updating i_disksize when extending file
2382 * without needing block allocation
2384 if (ext4_should_order_data(inode))
2385 ret = ext4_jbd2_file_inode(handle,
2388 EXT4_I(inode)->i_disksize = new_i_size;
2390 up_write(&EXT4_I(inode)->i_data_sem);
2393 ret2 = generic_write_end(file, mapping, pos, len, copied,
2398 ret2 = ext4_journal_stop(handle);
2402 return ret ? ret : copied;
2405 static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
2408 * Drop reserved blocks
2410 BUG_ON(!PageLocked(page));
2411 if (!page_has_buffers(page))
2414 ext4_da_page_release_reservation(page, offset);
2417 ext4_invalidatepage(page, offset);
2424 * bmap() is special. It gets used by applications such as lilo and by
2425 * the swapper to find the on-disk block of a specific piece of data.
2427 * Naturally, this is dangerous if the block concerned is still in the
2428 * journal. If somebody makes a swapfile on an ext4 data-journaling
2429 * filesystem and enables swap, then they may get a nasty shock when the
2430 * data getting swapped to that swapfile suddenly gets overwritten by
2431 * the original zero's written out previously to the journal and
2432 * awaiting writeback in the kernel's buffer cache.
2434 * So, if we see any bmap calls here on a modified, data-journaled file,
2435 * take extra steps to flush any blocks which might be in the cache.
2437 static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
2439 struct inode *inode = mapping->host;
2443 if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
2444 test_opt(inode->i_sb, DELALLOC)) {
2446 * With delalloc we want to sync the file
2447 * so that we can make sure we allocate
2450 filemap_write_and_wait(mapping);
2453 if (EXT4_I(inode)->i_state & EXT4_STATE_JDATA) {
2455 * This is a REALLY heavyweight approach, but the use of
2456 * bmap on dirty files is expected to be extremely rare:
2457 * only if we run lilo or swapon on a freshly made file
2458 * do we expect this to happen.
2460 * (bmap requires CAP_SYS_RAWIO so this does not
2461 * represent an unprivileged user DOS attack --- we'd be
2462 * in trouble if mortal users could trigger this path at
2465 * NB. EXT4_STATE_JDATA is not set on files other than
2466 * regular files. If somebody wants to bmap a directory
2467 * or symlink and gets confused because the buffer
2468 * hasn't yet been flushed to disk, they deserve
2469 * everything they get.
2472 EXT4_I(inode)->i_state &= ~EXT4_STATE_JDATA;
2473 journal = EXT4_JOURNAL(inode);
2474 jbd2_journal_lock_updates(journal);
2475 err = jbd2_journal_flush(journal);
2476 jbd2_journal_unlock_updates(journal);
2482 return generic_block_bmap(mapping,block,ext4_get_block);
2485 static int bget_one(handle_t *handle, struct buffer_head *bh)
2491 static int bput_one(handle_t *handle, struct buffer_head *bh)
2498 * Note that we don't need to start a transaction unless we're journaling data
2499 * because we should have holes filled from ext4_page_mkwrite(). We even don't
2500 * need to file the inode to the transaction's list in ordered mode because if
2501 * we are writing back data added by write(), the inode is already there and if
2502 * we are writing back data modified via mmap(), noone guarantees in which
2503 * transaction the data will hit the disk. In case we are journaling data, we
2504 * cannot start transaction directly because transaction start ranks above page
2505 * lock so we have to do some magic.
2507 * In all journaling modes block_write_full_page() will start the I/O.
2511 * ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
2516 * ext4_file_write() -> generic_file_write() -> __alloc_pages() -> ...
2518 * Same applies to ext4_get_block(). We will deadlock on various things like
2519 * lock_journal and i_data_sem
2521 * Setting PF_MEMALLOC here doesn't work - too many internal memory
2524 * 16May01: If we're reentered then journal_current_handle() will be
2525 * non-zero. We simply *return*.
2527 * 1 July 2001: @@@ FIXME:
2528 * In journalled data mode, a data buffer may be metadata against the
2529 * current transaction. But the same file is part of a shared mapping
2530 * and someone does a writepage() on it.
2532 * We will move the buffer onto the async_data list, but *after* it has
2533 * been dirtied. So there's a small window where we have dirty data on
2536 * Note that this only applies to the last partial page in the file. The
2537 * bit which block_write_full_page() uses prepare/commit for. (That's
2538 * broken code anyway: it's wrong for msync()).
2540 * It's a rare case: affects the final partial page, for journalled data
2541 * where the file is subject to bith write() and writepage() in the same
2542 * transction. To fix it we'll need a custom block_write_full_page().
2543 * We'll probably need that anyway for journalling writepage() output.
2545 * We don't honour synchronous mounts for writepage(). That would be
2546 * disastrous. Any write() or metadata operation will sync the fs for
2550 static int __ext4_normal_writepage(struct page *page,
2551 struct writeback_control *wbc)
2553 struct inode *inode = page->mapping->host;
2555 if (test_opt(inode->i_sb, NOBH))
2556 return nobh_writepage(page,
2557 ext4_normal_get_block_write, wbc);
2559 return block_write_full_page(page,
2560 ext4_normal_get_block_write,
2564 static int ext4_normal_writepage(struct page *page,
2565 struct writeback_control *wbc)
2567 struct inode *inode = page->mapping->host;
2568 loff_t size = i_size_read(inode);
2571 J_ASSERT(PageLocked(page));
2572 if (page->index == size >> PAGE_CACHE_SHIFT)
2573 len = size & ~PAGE_CACHE_MASK;
2575 len = PAGE_CACHE_SIZE;
2577 if (page_has_buffers(page)) {
2578 /* if page has buffers it should all be mapped
2579 * and allocated. If there are not buffers attached
2580 * to the page we know the page is dirty but it lost
2581 * buffers. That means that at some moment in time
2582 * after write_begin() / write_end() has been called
2583 * all buffers have been clean and thus they must have been
2584 * written at least once. So they are all mapped and we can
2585 * happily proceed with mapping them and writing the page.
2587 BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
2588 ext4_bh_unmapped_or_delay));
2591 if (!ext4_journal_current_handle())
2592 return __ext4_normal_writepage(page, wbc);
2594 redirty_page_for_writepage(wbc, page);
2599 static int __ext4_journalled_writepage(struct page *page,
2600 struct writeback_control *wbc)
2602 struct address_space *mapping = page->mapping;
2603 struct inode *inode = mapping->host;
2604 struct buffer_head *page_bufs;
2605 handle_t *handle = NULL;
2609 ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
2610 ext4_normal_get_block_write);
2614 page_bufs = page_buffers(page);
2615 walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE, NULL,
2617 /* As soon as we unlock the page, it can go away, but we have
2618 * references to buffers so we are safe */
2621 handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
2622 if (IS_ERR(handle)) {
2623 ret = PTR_ERR(handle);
2627 ret = walk_page_buffers(handle, page_bufs, 0,
2628 PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
2630 err = walk_page_buffers(handle, page_bufs, 0,
2631 PAGE_CACHE_SIZE, NULL, write_end_fn);
2634 err = ext4_journal_stop(handle);
2638 walk_page_buffers(handle, page_bufs, 0,
2639 PAGE_CACHE_SIZE, NULL, bput_one);
2640 EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
2649 static int ext4_journalled_writepage(struct page *page,
2650 struct writeback_control *wbc)
2652 struct inode *inode = page->mapping->host;
2653 loff_t size = i_size_read(inode);
2656 J_ASSERT(PageLocked(page));
2657 if (page->index == size >> PAGE_CACHE_SHIFT)
2658 len = size & ~PAGE_CACHE_MASK;
2660 len = PAGE_CACHE_SIZE;
2662 if (page_has_buffers(page)) {
2663 /* if page has buffers it should all be mapped
2664 * and allocated. If there are not buffers attached
2665 * to the page we know the page is dirty but it lost
2666 * buffers. That means that at some moment in time
2667 * after write_begin() / write_end() has been called
2668 * all buffers have been clean and thus they must have been
2669 * written at least once. So they are all mapped and we can
2670 * happily proceed with mapping them and writing the page.
2672 BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
2673 ext4_bh_unmapped_or_delay));
2676 if (ext4_journal_current_handle())
2679 if (PageChecked(page)) {
2681 * It's mmapped pagecache. Add buffers and journal it. There
2682 * doesn't seem much point in redirtying the page here.
2684 ClearPageChecked(page);
2685 return __ext4_journalled_writepage(page, wbc);
2688 * It may be a page full of checkpoint-mode buffers. We don't
2689 * really know unless we go poke around in the buffer_heads.
2690 * But block_write_full_page will do the right thing.
2692 return block_write_full_page(page,
2693 ext4_normal_get_block_write,
2697 redirty_page_for_writepage(wbc, page);
2702 static int ext4_readpage(struct file *file, struct page *page)
2704 return mpage_readpage(page, ext4_get_block);
2708 ext4_readpages(struct file *file, struct address_space *mapping,
2709 struct list_head *pages, unsigned nr_pages)
2711 return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
2714 static void ext4_invalidatepage(struct page *page, unsigned long offset)
2716 journal_t *journal = EXT4_JOURNAL(page->mapping->host);
2719 * If it's a full truncate we just forget about the pending dirtying
2722 ClearPageChecked(page);
2724 jbd2_journal_invalidatepage(journal, page, offset);
2727 static int ext4_releasepage(struct page *page, gfp_t wait)
2729 journal_t *journal = EXT4_JOURNAL(page->mapping->host);
2731 WARN_ON(PageChecked(page));
2732 if (!page_has_buffers(page))
2734 return jbd2_journal_try_to_free_buffers(journal, page, wait);
2738 * If the O_DIRECT write will extend the file then add this inode to the
2739 * orphan list. So recovery will truncate it back to the original size
2740 * if the machine crashes during the write.
2742 * If the O_DIRECT write is intantiating holes inside i_size and the machine
2743 * crashes then stale disk data _may_ be exposed inside the file. But current
2744 * VFS code falls back into buffered path in that case so we are safe.
2746 static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
2747 const struct iovec *iov, loff_t offset,
2748 unsigned long nr_segs)
2750 struct file *file = iocb->ki_filp;
2751 struct inode *inode = file->f_mapping->host;
2752 struct ext4_inode_info *ei = EXT4_I(inode);
2756 size_t count = iov_length(iov, nr_segs);
2759 loff_t final_size = offset + count;
2761 if (final_size > inode->i_size) {
2762 /* Credits for sb + inode write */
2763 handle = ext4_journal_start(inode, 2);
2764 if (IS_ERR(handle)) {
2765 ret = PTR_ERR(handle);
2768 ret = ext4_orphan_add(handle, inode);
2770 ext4_journal_stop(handle);
2774 ei->i_disksize = inode->i_size;
2775 ext4_journal_stop(handle);
2779 ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
2781 ext4_get_block, NULL);
2786 /* Credits for sb + inode write */
2787 handle = ext4_journal_start(inode, 2);
2788 if (IS_ERR(handle)) {
2789 /* This is really bad luck. We've written the data
2790 * but cannot extend i_size. Bail out and pretend
2791 * the write failed... */
2792 ret = PTR_ERR(handle);
2796 ext4_orphan_del(handle, inode);
2798 loff_t end = offset + ret;
2799 if (end > inode->i_size) {
2800 ei->i_disksize = end;
2801 i_size_write(inode, end);
2803 * We're going to return a positive `ret'
2804 * here due to non-zero-length I/O, so there's
2805 * no way of reporting error returns from
2806 * ext4_mark_inode_dirty() to userspace. So
2809 ext4_mark_inode_dirty(handle, inode);
2812 err = ext4_journal_stop(handle);
2821 * Pages can be marked dirty completely asynchronously from ext4's journalling
2822 * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do
2823 * much here because ->set_page_dirty is called under VFS locks. The page is
2824 * not necessarily locked.
2826 * We cannot just dirty the page and leave attached buffers clean, because the
2827 * buffers' dirty state is "definitive". We cannot just set the buffers dirty
2828 * or jbddirty because all the journalling code will explode.
2830 * So what we do is to mark the page "pending dirty" and next time writepage
2831 * is called, propagate that into the buffers appropriately.
2833 static int ext4_journalled_set_page_dirty(struct page *page)
2835 SetPageChecked(page);
2836 return __set_page_dirty_nobuffers(page);
2839 static const struct address_space_operations ext4_ordered_aops = {
2840 .readpage = ext4_readpage,
2841 .readpages = ext4_readpages,
2842 .writepage = ext4_normal_writepage,
2843 .sync_page = block_sync_page,
2844 .write_begin = ext4_write_begin,
2845 .write_end = ext4_ordered_write_end,
2847 .invalidatepage = ext4_invalidatepage,
2848 .releasepage = ext4_releasepage,
2849 .direct_IO = ext4_direct_IO,
2850 .migratepage = buffer_migrate_page,
2851 .is_partially_uptodate = block_is_partially_uptodate,
2854 static const struct address_space_operations ext4_writeback_aops = {
2855 .readpage = ext4_readpage,
2856 .readpages = ext4_readpages,
2857 .writepage = ext4_normal_writepage,
2858 .sync_page = block_sync_page,
2859 .write_begin = ext4_write_begin,
2860 .write_end = ext4_writeback_write_end,
2862 .invalidatepage = ext4_invalidatepage,
2863 .releasepage = ext4_releasepage,
2864 .direct_IO = ext4_direct_IO,
2865 .migratepage = buffer_migrate_page,
2866 .is_partially_uptodate = block_is_partially_uptodate,
2869 static const struct address_space_operations ext4_journalled_aops = {
2870 .readpage = ext4_readpage,
2871 .readpages = ext4_readpages,
2872 .writepage = ext4_journalled_writepage,
2873 .sync_page = block_sync_page,
2874 .write_begin = ext4_write_begin,
2875 .write_end = ext4_journalled_write_end,
2876 .set_page_dirty = ext4_journalled_set_page_dirty,
2878 .invalidatepage = ext4_invalidatepage,
2879 .releasepage = ext4_releasepage,
2880 .is_partially_uptodate = block_is_partially_uptodate,
2883 static const struct address_space_operations ext4_da_aops = {
2884 .readpage = ext4_readpage,
2885 .readpages = ext4_readpages,
2886 .writepage = ext4_da_writepage,
2887 .writepages = ext4_da_writepages,
2888 .sync_page = block_sync_page,
2889 .write_begin = ext4_da_write_begin,
2890 .write_end = ext4_da_write_end,
2892 .invalidatepage = ext4_da_invalidatepage,
2893 .releasepage = ext4_releasepage,
2894 .direct_IO = ext4_direct_IO,
2895 .migratepage = buffer_migrate_page,
2896 .is_partially_uptodate = block_is_partially_uptodate,
2899 void ext4_set_aops(struct inode *inode)
2901 if (ext4_should_order_data(inode) &&
2902 test_opt(inode->i_sb, DELALLOC))
2903 inode->i_mapping->a_ops = &ext4_da_aops;
2904 else if (ext4_should_order_data(inode))
2905 inode->i_mapping->a_ops = &ext4_ordered_aops;
2906 else if (ext4_should_writeback_data(inode) &&
2907 test_opt(inode->i_sb, DELALLOC))
2908 inode->i_mapping->a_ops = &ext4_da_aops;
2909 else if (ext4_should_writeback_data(inode))
2910 inode->i_mapping->a_ops = &ext4_writeback_aops;
2912 inode->i_mapping->a_ops = &ext4_journalled_aops;
2916 * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
2917 * up to the end of the block which corresponds to `from'.
2918 * This required during truncate. We need to physically zero the tail end
2919 * of that block so it doesn't yield old data if the file is later grown.
2921 int ext4_block_truncate_page(handle_t *handle,
2922 struct address_space *mapping, loff_t from)
2924 ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
2925 unsigned offset = from & (PAGE_CACHE_SIZE-1);
2926 unsigned blocksize, length, pos;
2928 struct inode *inode = mapping->host;
2929 struct buffer_head *bh;
2933 page = grab_cache_page(mapping, from >> PAGE_CACHE_SHIFT);
2937 blocksize = inode->i_sb->s_blocksize;
2938 length = blocksize - (offset & (blocksize - 1));
2939 iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
2942 * For "nobh" option, we can only work if we don't need to
2943 * read-in the page - otherwise we create buffers to do the IO.
2945 if (!page_has_buffers(page) && test_opt(inode->i_sb, NOBH) &&
2946 ext4_should_writeback_data(inode) && PageUptodate(page)) {
2947 zero_user(page, offset, length);
2948 set_page_dirty(page);
2952 if (!page_has_buffers(page))
2953 create_empty_buffers(page, blocksize, 0);
2955 /* Find the buffer that contains "offset" */
2956 bh = page_buffers(page);
2958 while (offset >= pos) {
2959 bh = bh->b_this_page;
2965 if (buffer_freed(bh)) {
2966 BUFFER_TRACE(bh, "freed: skip");
2970 if (!buffer_mapped(bh)) {
2971 BUFFER_TRACE(bh, "unmapped");
2972 ext4_get_block(inode, iblock, bh, 0);
2973 /* unmapped? It's a hole - nothing to do */
2974 if (!buffer_mapped(bh)) {
2975 BUFFER_TRACE(bh, "still unmapped");
2980 /* Ok, it's mapped. Make sure it's up-to-date */
2981 if (PageUptodate(page))
2982 set_buffer_uptodate(bh);
2984 if (!buffer_uptodate(bh)) {
2986 ll_rw_block(READ, 1, &bh);
2988 /* Uhhuh. Read error. Complain and punt. */
2989 if (!buffer_uptodate(bh))
2993 if (ext4_should_journal_data(inode)) {
2994 BUFFER_TRACE(bh, "get write access");
2995 err = ext4_journal_get_write_access(handle, bh);
3000 zero_user(page, offset, length);
3002 BUFFER_TRACE(bh, "zeroed end of block");
3005 if (ext4_should_journal_data(inode)) {
3006 err = ext4_journal_dirty_metadata(handle, bh);
3008 if (ext4_should_order_data(inode))
3009 err = ext4_jbd2_file_inode(handle, inode);
3010 mark_buffer_dirty(bh);
3015 page_cache_release(page);
3020 * Probably it should be a library function... search for first non-zero word
3021 * or memcmp with zero_page, whatever is better for particular architecture.
3024 static inline int all_zeroes(__le32 *p, __le32 *q)
3033 * ext4_find_shared - find the indirect blocks for partial truncation.
3034 * @inode: inode in question
3035 * @depth: depth of the affected branch
3036 * @offsets: offsets of pointers in that branch (see ext4_block_to_path)
3037 * @chain: place to store the pointers to partial indirect blocks
3038 * @top: place to the (detached) top of branch
3040 * This is a helper function used by ext4_truncate().
3042 * When we do truncate() we may have to clean the ends of several
3043 * indirect blocks but leave the blocks themselves alive. Block is
3044 * partially truncated if some data below the new i_size is refered
3045 * from it (and it is on the path to the first completely truncated
3046 * data block, indeed). We have to free the top of that path along
3047 * with everything to the right of the path. Since no allocation
3048 * past the truncation point is possible until ext4_truncate()
3049 * finishes, we may safely do the latter, but top of branch may
3050 * require special attention - pageout below the truncation point
3051 * might try to populate it.
3053 * We atomically detach the top of branch from the tree, store the
3054 * block number of its root in *@top, pointers to buffer_heads of
3055 * partially truncated blocks - in @chain[].bh and pointers to
3056 * their last elements that should not be removed - in
3057 * @chain[].p. Return value is the pointer to last filled element
3060 * The work left to caller to do the actual freeing of subtrees:
3061 * a) free the subtree starting from *@top
3062 * b) free the subtrees whose roots are stored in
3063 * (@chain[i].p+1 .. end of @chain[i].bh->b_data)
3064 * c) free the subtrees growing from the inode past the @chain[0].
3065 * (no partially truncated stuff there). */
3067 static Indirect *ext4_find_shared(struct inode *inode, int depth,
3068 ext4_lblk_t offsets[4], Indirect chain[4], __le32 *top)
3070 Indirect *partial, *p;
3074 /* Make k index the deepest non-null offest + 1 */
3075 for (k = depth; k > 1 && !offsets[k-1]; k--)
3077 partial = ext4_get_branch(inode, k, offsets, chain, &err);
3078 /* Writer: pointers */
3080 partial = chain + k-1;
3082 * If the branch acquired continuation since we've looked at it -
3083 * fine, it should all survive and (new) top doesn't belong to us.
3085 if (!partial->key && *partial->p)
3088 for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
3091 * OK, we've found the last block that must survive. The rest of our
3092 * branch should be detached before unlocking. However, if that rest
3093 * of branch is all ours and does not grow immediately from the inode
3094 * it's easier to cheat and just decrement partial->p.
3096 if (p == chain + k - 1 && p > chain) {
3100 /* Nope, don't do this in ext4. Must leave the tree intact */
3107 while(partial > p) {
3108 brelse(partial->bh);
3116 * Zero a number of block pointers in either an inode or an indirect block.
3117 * If we restart the transaction we must again get write access to the
3118 * indirect block for further modification.
3120 * We release `count' blocks on disk, but (last - first) may be greater
3121 * than `count' because there can be holes in there.
3123 static void ext4_clear_blocks(handle_t *handle, struct inode *inode,
3124 struct buffer_head *bh, ext4_fsblk_t block_to_free,
3125 unsigned long count, __le32 *first, __le32 *last)
3128 if (try_to_extend_transaction(handle, inode)) {
3130 BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
3131 ext4_journal_dirty_metadata(handle, bh);
3133 ext4_mark_inode_dirty(handle, inode);
3134 ext4_journal_test_restart(handle, inode);
3136 BUFFER_TRACE(bh, "retaking write access");
3137 ext4_journal_get_write_access(handle, bh);
3142 * Any buffers which are on the journal will be in memory. We find
3143 * them on the hash table so jbd2_journal_revoke() will run jbd2_journal_forget()
3144 * on them. We've already detached each block from the file, so
3145 * bforget() in jbd2_journal_forget() should be safe.
3147 * AKPM: turn on bforget in jbd2_journal_forget()!!!
3149 for (p = first; p < last; p++) {
3150 u32 nr = le32_to_cpu(*p);
3152 struct buffer_head *tbh;
3155 tbh = sb_find_get_block(inode->i_sb, nr);
3156 ext4_forget(handle, 0, inode, tbh, nr);
3160 ext4_free_blocks(handle, inode, block_to_free, count, 0);
3164 * ext4_free_data - free a list of data blocks
3165 * @handle: handle for this transaction
3166 * @inode: inode we are dealing with
3167 * @this_bh: indirect buffer_head which contains *@first and *@last
3168 * @first: array of block numbers
3169 * @last: points immediately past the end of array
3171 * We are freeing all blocks refered from that array (numbers are stored as
3172 * little-endian 32-bit) and updating @inode->i_blocks appropriately.
3174 * We accumulate contiguous runs of blocks to free. Conveniently, if these
3175 * blocks are contiguous then releasing them at one time will only affect one
3176 * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
3177 * actually use a lot of journal space.
3179 * @this_bh will be %NULL if @first and @last point into the inode's direct
3182 static void ext4_free_data(handle_t *handle, struct inode *inode,
3183 struct buffer_head *this_bh,
3184 __le32 *first, __le32 *last)
3186 ext4_fsblk_t block_to_free = 0; /* Starting block # of a run */
3187 unsigned long count = 0; /* Number of blocks in the run */
3188 __le32 *block_to_free_p = NULL; /* Pointer into inode/ind
3191 ext4_fsblk_t nr; /* Current block # */
3192 __le32 *p; /* Pointer into inode/ind
3193 for current block */
3196 if (this_bh) { /* For indirect block */
3197 BUFFER_TRACE(this_bh, "get_write_access");
3198 err = ext4_journal_get_write_access(handle, this_bh);
3199 /* Important: if we can't update the indirect pointers
3200 * to the blocks, we can't free them. */
3205 for (p = first; p < last; p++) {
3206 nr = le32_to_cpu(*p);
3208 /* accumulate blocks to free if they're contiguous */
3211 block_to_free_p = p;
3213 } else if (nr == block_to_free + count) {
3216 ext4_clear_blocks(handle, inode, this_bh,
3218 count, block_to_free_p, p);
3220 block_to_free_p = p;
3227 ext4_clear_blocks(handle, inode, this_bh, block_to_free,
3228 count, block_to_free_p, p);
3231 BUFFER_TRACE(this_bh, "call ext4_journal_dirty_metadata");
3234 * The buffer head should have an attached journal head at this
3235 * point. However, if the data is corrupted and an indirect
3236 * block pointed to itself, it would have been detached when
3237 * the block was cleared. Check for this instead of OOPSing.
3240 ext4_journal_dirty_metadata(handle, this_bh);
3242 ext4_error(inode->i_sb, __func__,
3243 "circular indirect block detected, "
3244 "inode=%lu, block=%llu",
3246 (unsigned long long) this_bh->b_blocknr);
3251 * ext4_free_branches - free an array of branches
3252 * @handle: JBD handle for this transaction
3253 * @inode: inode we are dealing with
3254 * @parent_bh: the buffer_head which contains *@first and *@last
3255 * @first: array of block numbers
3256 * @last: pointer immediately past the end of array
3257 * @depth: depth of the branches to free
3259 * We are freeing all blocks refered from these branches (numbers are
3260 * stored as little-endian 32-bit) and updating @inode->i_blocks
3263 static void ext4_free_branches(handle_t *handle, struct inode *inode,
3264 struct buffer_head *parent_bh,
3265 __le32 *first, __le32 *last, int depth)
3270 if (is_handle_aborted(handle))
3274 struct buffer_head *bh;
3275 int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
3277 while (--p >= first) {
3278 nr = le32_to_cpu(*p);
3280 continue; /* A hole */
3282 /* Go read the buffer for the next level down */
3283 bh = sb_bread(inode->i_sb, nr);
3286 * A read failure? Report error and clear slot
3290 ext4_error(inode->i_sb, "ext4_free_branches",
3291 "Read failure, inode=%lu, block=%llu",
3296 /* This zaps the entire block. Bottom up. */
3297 BUFFER_TRACE(bh, "free child branches");
3298 ext4_free_branches(handle, inode, bh,
3299 (__le32*)bh->b_data,
3300 (__le32*)bh->b_data + addr_per_block,
3304 * We've probably journalled the indirect block several
3305 * times during the truncate. But it's no longer
3306 * needed and we now drop it from the transaction via
3307 * jbd2_journal_revoke().
3309 * That's easy if it's exclusively part of this
3310 * transaction. But if it's part of the committing
3311 * transaction then jbd2_journal_forget() will simply
3312 * brelse() it. That means that if the underlying
3313 * block is reallocated in ext4_get_block(),
3314 * unmap_underlying_metadata() will find this block
3315 * and will try to get rid of it. damn, damn.
3317 * If this block has already been committed to the
3318 * journal, a revoke record will be written. And
3319 * revoke records must be emitted *before* clearing
3320 * this block's bit in the bitmaps.
3322 ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
3325 * Everything below this this pointer has been
3326 * released. Now let this top-of-subtree go.
3328 * We want the freeing of this indirect block to be
3329 * atomic in the journal with the updating of the
3330 * bitmap block which owns it. So make some room in
3333 * We zero the parent pointer *after* freeing its
3334 * pointee in the bitmaps, so if extend_transaction()
3335 * for some reason fails to put the bitmap changes and
3336 * the release into the same transaction, recovery
3337 * will merely complain about releasing a free block,
3338 * rather than leaking blocks.
3340 if (is_handle_aborted(handle))
3342 if (try_to_extend_transaction(handle, inode)) {
3343 ext4_mark_inode_dirty(handle, inode);
3344 ext4_journal_test_restart(handle, inode);
3347 ext4_free_blocks(handle, inode, nr, 1, 1);
3351 * The block which we have just freed is
3352 * pointed to by an indirect block: journal it
3354 BUFFER_TRACE(parent_bh, "get_write_access");
3355 if (!ext4_journal_get_write_access(handle,
3358 BUFFER_TRACE(parent_bh,
3359 "call ext4_journal_dirty_metadata");
3360 ext4_journal_dirty_metadata(handle,
3366 /* We have reached the bottom of the tree. */
3367 BUFFER_TRACE(parent_bh, "free data blocks");
3368 ext4_free_data(handle, inode, parent_bh, first, last);
3372 int ext4_can_truncate(struct inode *inode)
3374 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
3376 if (S_ISREG(inode->i_mode))
3378 if (S_ISDIR(inode->i_mode))
3380 if (S_ISLNK(inode->i_mode))
3381 return !ext4_inode_is_fast_symlink(inode);
3388 * We block out ext4_get_block() block instantiations across the entire
3389 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
3390 * simultaneously on behalf of the same inode.
3392 * As we work through the truncate and commmit bits of it to the journal there
3393 * is one core, guiding principle: the file's tree must always be consistent on
3394 * disk. We must be able to restart the truncate after a crash.
3396 * The file's tree may be transiently inconsistent in memory (although it
3397 * probably isn't), but whenever we close off and commit a journal transaction,
3398 * the contents of (the filesystem + the journal) must be consistent and
3399 * restartable. It's pretty simple, really: bottom up, right to left (although
3400 * left-to-right works OK too).
3402 * Note that at recovery time, journal replay occurs *before* the restart of
3403 * truncate against the orphan inode list.
3405 * The committed inode has the new, desired i_size (which is the same as
3406 * i_disksize in this case). After a crash, ext4_orphan_cleanup() will see
3407 * that this inode's truncate did not complete and it will again call
3408 * ext4_truncate() to have another go. So there will be instantiated blocks
3409 * to the right of the truncation point in a crashed ext4 filesystem. But
3410 * that's fine - as long as they are linked from the inode, the post-crash
3411 * ext4_truncate() run will find them and release them.
3413 void ext4_truncate(struct inode *inode)
3416 struct ext4_inode_info *ei = EXT4_I(inode);
3417 __le32 *i_data = ei->i_data;
3418 int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
3419 struct address_space *mapping = inode->i_mapping;
3420 ext4_lblk_t offsets[4];
3425 ext4_lblk_t last_block;
3426 unsigned blocksize = inode->i_sb->s_blocksize;
3428 if (!ext4_can_truncate(inode))
3431 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
3432 ext4_ext_truncate(inode);
3436 handle = start_transaction(inode);
3438 return; /* AKPM: return what? */
3440 last_block = (inode->i_size + blocksize-1)
3441 >> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
3443 if (inode->i_size & (blocksize - 1))
3444 if (ext4_block_truncate_page(handle, mapping, inode->i_size))
3447 n = ext4_block_to_path(inode, last_block, offsets, NULL);
3449 goto out_stop; /* error */
3452 * OK. This truncate is going to happen. We add the inode to the
3453 * orphan list, so that if this truncate spans multiple transactions,
3454 * and we crash, we will resume the truncate when the filesystem
3455 * recovers. It also marks the inode dirty, to catch the new size.
3457 * Implication: the file must always be in a sane, consistent
3458 * truncatable state while each transaction commits.
3460 if (ext4_orphan_add(handle, inode))
3464 * From here we block out all ext4_get_block() callers who want to
3465 * modify the block allocation tree.
3467 down_write(&ei->i_data_sem);
3469 * The orphan list entry will now protect us from any crash which
3470 * occurs before the truncate completes, so it is now safe to propagate
3471 * the new, shorter inode size (held for now in i_size) into the
3472 * on-disk inode. We do this via i_disksize, which is the value which
3473 * ext4 *really* writes onto the disk inode.
3475 ei->i_disksize = inode->i_size;
3477 if (n == 1) { /* direct blocks */
3478 ext4_free_data(handle, inode, NULL, i_data+offsets[0],
3479 i_data + EXT4_NDIR_BLOCKS);
3483 partial = ext4_find_shared(inode, n, offsets, chain, &nr);
3484 /* Kill the top of shared branch (not detached) */
3486 if (partial == chain) {
3487 /* Shared branch grows from the inode */
3488 ext4_free_branches(handle, inode, NULL,
3489 &nr, &nr+1, (chain+n-1) - partial);
3492 * We mark the inode dirty prior to restart,
3493 * and prior to stop. No need for it here.
3496 /* Shared branch grows from an indirect block */
3497 BUFFER_TRACE(partial->bh, "get_write_access");
3498 ext4_free_branches(handle, inode, partial->bh,
3500 partial->p+1, (chain+n-1) - partial);
3503 /* Clear the ends of indirect blocks on the shared branch */
3504 while (partial > chain) {
3505 ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
3506 (__le32*)partial->bh->b_data+addr_per_block,
3507 (chain+n-1) - partial);
3508 BUFFER_TRACE(partial->bh, "call brelse");
3509 brelse (partial->bh);
3513 /* Kill the remaining (whole) subtrees */
3514 switch (offsets[0]) {
3516 nr = i_data[EXT4_IND_BLOCK];
3518 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
3519 i_data[EXT4_IND_BLOCK] = 0;
3521 case EXT4_IND_BLOCK:
3522 nr = i_data[EXT4_DIND_BLOCK];
3524 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
3525 i_data[EXT4_DIND_BLOCK] = 0;
3527 case EXT4_DIND_BLOCK:
3528 nr = i_data[EXT4_TIND_BLOCK];
3530 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
3531 i_data[EXT4_TIND_BLOCK] = 0;
3533 case EXT4_TIND_BLOCK:
3537 ext4_discard_reservation(inode);
3539 up_write(&ei->i_data_sem);
3540 inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
3541 ext4_mark_inode_dirty(handle, inode);
3544 * In a multi-transaction truncate, we only make the final transaction
3551 * If this was a simple ftruncate(), and the file will remain alive
3552 * then we need to clear up the orphan record which we created above.
3553 * However, if this was a real unlink then we were called by
3554 * ext4_delete_inode(), and we allow that function to clean up the
3555 * orphan info for us.
3558 ext4_orphan_del(handle, inode);
3560 ext4_journal_stop(handle);
3563 static ext4_fsblk_t ext4_get_inode_block(struct super_block *sb,
3564 unsigned long ino, struct ext4_iloc *iloc)
3566 ext4_group_t block_group;
3567 unsigned long offset;
3569 struct ext4_group_desc *gdp;
3571 if (!ext4_valid_inum(sb, ino)) {
3573 * This error is already checked for in namei.c unless we are
3574 * looking at an NFS filehandle, in which case no error
3580 block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
3581 gdp = ext4_get_group_desc(sb, block_group, NULL);
3586 * Figure out the offset within the block group inode table
3588 offset = ((ino - 1) % EXT4_INODES_PER_GROUP(sb)) *
3589 EXT4_INODE_SIZE(sb);
3590 block = ext4_inode_table(sb, gdp) +
3591 (offset >> EXT4_BLOCK_SIZE_BITS(sb));
3593 iloc->block_group = block_group;
3594 iloc->offset = offset & (EXT4_BLOCK_SIZE(sb) - 1);
3599 * ext4_get_inode_loc returns with an extra refcount against the inode's
3600 * underlying buffer_head on success. If 'in_mem' is true, we have all
3601 * data in memory that is needed to recreate the on-disk version of this
3604 static int __ext4_get_inode_loc(struct inode *inode,
3605 struct ext4_iloc *iloc, int in_mem)
3608 struct buffer_head *bh;
3610 block = ext4_get_inode_block(inode->i_sb, inode->i_ino, iloc);
3614 bh = sb_getblk(inode->i_sb, block);
3616 ext4_error (inode->i_sb, "ext4_get_inode_loc",
3617 "unable to read inode block - "
3618 "inode=%lu, block=%llu",
3619 inode->i_ino, block);
3622 if (!buffer_uptodate(bh)) {
3626 * If the buffer has the write error flag, we have failed
3627 * to write out another inode in the same block. In this
3628 * case, we don't have to read the block because we may
3629 * read the old inode data successfully.
3631 if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
3632 set_buffer_uptodate(bh);
3634 if (buffer_uptodate(bh)) {
3635 /* someone brought it uptodate while we waited */
3641 * If we have all information of the inode in memory and this
3642 * is the only valid inode in the block, we need not read the
3646 struct buffer_head *bitmap_bh;
3647 struct ext4_group_desc *desc;
3648 int inodes_per_buffer;
3649 int inode_offset, i;
3650 ext4_group_t block_group;
3653 block_group = (inode->i_ino - 1) /
3654 EXT4_INODES_PER_GROUP(inode->i_sb);
3655 inodes_per_buffer = bh->b_size /
3656 EXT4_INODE_SIZE(inode->i_sb);
3657 inode_offset = ((inode->i_ino - 1) %
3658 EXT4_INODES_PER_GROUP(inode->i_sb));
3659 start = inode_offset & ~(inodes_per_buffer - 1);
3661 /* Is the inode bitmap in cache? */
3662 desc = ext4_get_group_desc(inode->i_sb,
3667 bitmap_bh = sb_getblk(inode->i_sb,
3668 ext4_inode_bitmap(inode->i_sb, desc));
3673 * If the inode bitmap isn't in cache then the
3674 * optimisation may end up performing two reads instead
3675 * of one, so skip it.
3677 if (!buffer_uptodate(bitmap_bh)) {
3681 for (i = start; i < start + inodes_per_buffer; i++) {
3682 if (i == inode_offset)
3684 if (ext4_test_bit(i, bitmap_bh->b_data))
3688 if (i == start + inodes_per_buffer) {
3689 /* all other inodes are free, so skip I/O */
3690 memset(bh->b_data, 0, bh->b_size);
3691 set_buffer_uptodate(bh);
3699 * There are other valid inodes in the buffer, this inode
3700 * has in-inode xattrs, or we don't have this inode in memory.
3701 * Read the block from disk.
3704 bh->b_end_io = end_buffer_read_sync;
3705 submit_bh(READ_META, bh);
3707 if (!buffer_uptodate(bh)) {
3708 ext4_error(inode->i_sb, "ext4_get_inode_loc",
3709 "unable to read inode block - "
3710 "inode=%lu, block=%llu",
3711 inode->i_ino, block);
3721 int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
3723 /* We have all inode data except xattrs in memory here. */
3724 return __ext4_get_inode_loc(inode, iloc,
3725 !(EXT4_I(inode)->i_state & EXT4_STATE_XATTR));
3728 void ext4_set_inode_flags(struct inode *inode)
3730 unsigned int flags = EXT4_I(inode)->i_flags;
3732 inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
3733 if (flags & EXT4_SYNC_FL)
3734 inode->i_flags |= S_SYNC;
3735 if (flags & EXT4_APPEND_FL)
3736 inode->i_flags |= S_APPEND;
3737 if (flags & EXT4_IMMUTABLE_FL)
3738 inode->i_flags |= S_IMMUTABLE;
3739 if (flags & EXT4_NOATIME_FL)
3740 inode->i_flags |= S_NOATIME;
3741 if (flags & EXT4_DIRSYNC_FL)
3742 inode->i_flags |= S_DIRSYNC;
3745 /* Propagate flags from i_flags to EXT4_I(inode)->i_flags */
3746 void ext4_get_inode_flags(struct ext4_inode_info *ei)
3748 unsigned int flags = ei->vfs_inode.i_flags;
3750 ei->i_flags &= ~(EXT4_SYNC_FL|EXT4_APPEND_FL|
3751 EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|EXT4_DIRSYNC_FL);
3753 ei->i_flags |= EXT4_SYNC_FL;
3754 if (flags & S_APPEND)
3755 ei->i_flags |= EXT4_APPEND_FL;
3756 if (flags & S_IMMUTABLE)
3757 ei->i_flags |= EXT4_IMMUTABLE_FL;
3758 if (flags & S_NOATIME)
3759 ei->i_flags |= EXT4_NOATIME_FL;
3760 if (flags & S_DIRSYNC)
3761 ei->i_flags |= EXT4_DIRSYNC_FL;
3763 static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
3764 struct ext4_inode_info *ei)
3767 struct inode *inode = &(ei->vfs_inode);
3768 struct super_block *sb = inode->i_sb;
3770 if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
3771 EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
3772 /* we are using combined 48 bit field */
3773 i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 |
3774 le32_to_cpu(raw_inode->i_blocks_lo);
3775 if (ei->i_flags & EXT4_HUGE_FILE_FL) {
3776 /* i_blocks represent file system block size */
3777 return i_blocks << (inode->i_blkbits - 9);
3782 return le32_to_cpu(raw_inode->i_blocks_lo);
3786 struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
3788 struct ext4_iloc iloc;
3789 struct ext4_inode *raw_inode;
3790 struct ext4_inode_info *ei;
3791 struct buffer_head *bh;
3792 struct inode *inode;
3796 inode = iget_locked(sb, ino);
3798 return ERR_PTR(-ENOMEM);
3799 if (!(inode->i_state & I_NEW))
3803 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
3804 ei->i_acl = EXT4_ACL_NOT_CACHED;
3805 ei->i_default_acl = EXT4_ACL_NOT_CACHED;
3807 ei->i_block_alloc_info = NULL;
3809 ret = __ext4_get_inode_loc(inode, &iloc, 0);
3813 raw_inode = ext4_raw_inode(&iloc);
3814 inode->i_mode = le16_to_cpu(raw_inode->i_mode);
3815 inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
3816 inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
3817 if(!(test_opt (inode->i_sb, NO_UID32))) {
3818 inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
3819 inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
3821 inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
3824 ei->i_dir_start_lookup = 0;
3825 ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
3826 /* We now have enough fields to check if the inode was active or not.
3827 * This is needed because nfsd might try to access dead inodes
3828 * the test is that same one that e2fsck uses
3829 * NeilBrown 1999oct15
3831 if (inode->i_nlink == 0) {
3832 if (inode->i_mode == 0 ||
3833 !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
3834 /* this inode is deleted */
3839 /* The only unlinked inodes we let through here have
3840 * valid i_mode and are being read by the orphan
3841 * recovery code: that's fine, we're about to complete
3842 * the process of deleting those. */
3844 ei->i_flags = le32_to_cpu(raw_inode->i_flags);
3845 inode->i_blocks = ext4_inode_blocks(raw_inode, ei);
3846 ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo);
3847 if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
3848 cpu_to_le32(EXT4_OS_HURD)) {
3850 ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
3852 inode->i_size = ext4_isize(raw_inode);
3853 ei->i_disksize = inode->i_size;
3854 inode->i_generation = le32_to_cpu(raw_inode->i_generation);
3855 ei->i_block_group = iloc.block_group;
3857 * NOTE! The in-memory inode i_data array is in little-endian order
3858 * even on big-endian machines: we do NOT byteswap the block numbers!
3860 for (block = 0; block < EXT4_N_BLOCKS; block++)
3861 ei->i_data[block] = raw_inode->i_block[block];
3862 INIT_LIST_HEAD(&ei->i_orphan);
3864 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
3865 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
3866 if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
3867 EXT4_INODE_SIZE(inode->i_sb)) {
3872 if (ei->i_extra_isize == 0) {
3873 /* The extra space is currently unused. Use it. */
3874 ei->i_extra_isize = sizeof(struct ext4_inode) -
3875 EXT4_GOOD_OLD_INODE_SIZE;
3877 __le32 *magic = (void *)raw_inode +
3878 EXT4_GOOD_OLD_INODE_SIZE +
3880 if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
3881 ei->i_state |= EXT4_STATE_XATTR;
3884 ei->i_extra_isize = 0;
3886 EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode);
3887 EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode);
3888 EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode);
3889 EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode);
3891 inode->i_version = le32_to_cpu(raw_inode->i_disk_version);
3892 if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
3893 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
3895 (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32;
3898 if (S_ISREG(inode->i_mode)) {
3899 inode->i_op = &ext4_file_inode_operations;
3900 inode->i_fop = &ext4_file_operations;
3901 ext4_set_aops(inode);
3902 } else if (S_ISDIR(inode->i_mode)) {
3903 inode->i_op = &ext4_dir_inode_operations;
3904 inode->i_fop = &ext4_dir_operations;
3905 } else if (S_ISLNK(inode->i_mode)) {
3906 if (ext4_inode_is_fast_symlink(inode))
3907 inode->i_op = &ext4_fast_symlink_inode_operations;
3909 inode->i_op = &ext4_symlink_inode_operations;
3910 ext4_set_aops(inode);
3913 inode->i_op = &ext4_special_inode_operations;
3914 if (raw_inode->i_block[0])
3915 init_special_inode(inode, inode->i_mode,
3916 old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
3918 init_special_inode(inode, inode->i_mode,
3919 new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
3922 ext4_set_inode_flags(inode);
3923 unlock_new_inode(inode);
3928 return ERR_PTR(ret);
3931 static int ext4_inode_blocks_set(handle_t *handle,
3932 struct ext4_inode *raw_inode,
3933 struct ext4_inode_info *ei)
3935 struct inode *inode = &(ei->vfs_inode);
3936 u64 i_blocks = inode->i_blocks;
3937 struct super_block *sb = inode->i_sb;
3940 if (i_blocks <= ~0U) {
3942 * i_blocks can be represnted in a 32 bit variable
3943 * as multiple of 512 bytes
3945 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
3946 raw_inode->i_blocks_high = 0;
3947 ei->i_flags &= ~EXT4_HUGE_FILE_FL;
3948 } else if (i_blocks <= 0xffffffffffffULL) {
3950 * i_blocks can be represented in a 48 bit variable
3951 * as multiple of 512 bytes
3953 err = ext4_update_rocompat_feature(handle, sb,
3954 EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
3957 /* i_block is stored in the split 48 bit fields */
3958 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
3959 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
3960 ei->i_flags &= ~EXT4_HUGE_FILE_FL;
3963 * i_blocks should be represented in a 48 bit variable
3964 * as multiple of file system block size
3966 err = ext4_update_rocompat_feature(handle, sb,
3967 EXT4_FEATURE_RO_COMPAT_HUGE_FILE);
3970 ei->i_flags |= EXT4_HUGE_FILE_FL;
3971 /* i_block is stored in file system block size */
3972 i_blocks = i_blocks >> (inode->i_blkbits - 9);
3973 raw_inode->i_blocks_lo = cpu_to_le32(i_blocks);
3974 raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32);
3981 * Post the struct inode info into an on-disk inode location in the
3982 * buffer-cache. This gobbles the caller's reference to the
3983 * buffer_head in the inode location struct.
3985 * The caller must have write access to iloc->bh.
3987 static int ext4_do_update_inode(handle_t *handle,
3988 struct inode *inode,
3989 struct ext4_iloc *iloc)
3991 struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
3992 struct ext4_inode_info *ei = EXT4_I(inode);
3993 struct buffer_head *bh = iloc->bh;
3994 int err = 0, rc, block;
3996 /* For fields not not tracking in the in-memory inode,
3997 * initialise them to zero for new inodes. */
3998 if (ei->i_state & EXT4_STATE_NEW)
3999 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
4001 ext4_get_inode_flags(ei);
4002 raw_inode->i_mode = cpu_to_le16(inode->i_mode);
4003 if(!(test_opt(inode->i_sb, NO_UID32))) {
4004 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
4005 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid));
4007 * Fix up interoperability with old kernels. Otherwise, old inodes get
4008 * re-used with the upper 16 bits of the uid/gid intact
4011 raw_inode->i_uid_high =
4012 cpu_to_le16(high_16_bits(inode->i_uid));
4013 raw_inode->i_gid_high =
4014 cpu_to_le16(high_16_bits(inode->i_gid));
4016 raw_inode->i_uid_high = 0;
4017 raw_inode->i_gid_high = 0;
4020 raw_inode->i_uid_low =
4021 cpu_to_le16(fs_high2lowuid(inode->i_uid));
4022 raw_inode->i_gid_low =
4023 cpu_to_le16(fs_high2lowgid(inode->i_gid));
4024 raw_inode->i_uid_high = 0;
4025 raw_inode->i_gid_high = 0;
4027 raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
4029 EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode);
4030 EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode);
4031 EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode);
4032 EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode);
4034 if (ext4_inode_blocks_set(handle, raw_inode, ei))
4036 raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
4037 /* clear the migrate flag in the raw_inode */
4038 raw_inode->i_flags = cpu_to_le32(ei->i_flags & ~EXT4_EXT_MIGRATE);
4039 if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
4040 cpu_to_le32(EXT4_OS_HURD))
4041 raw_inode->i_file_acl_high =
4042 cpu_to_le16(ei->i_file_acl >> 32);
4043 raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl);
4044 ext4_isize_set(raw_inode, ei->i_disksize);
4045 if (ei->i_disksize > 0x7fffffffULL) {
4046 struct super_block *sb = inode->i_sb;
4047 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
4048 EXT4_FEATURE_RO_COMPAT_LARGE_FILE) ||
4049 EXT4_SB(sb)->s_es->s_rev_level ==
4050 cpu_to_le32(EXT4_GOOD_OLD_REV)) {
4051 /* If this is the first large file
4052 * created, add a flag to the superblock.
4054 err = ext4_journal_get_write_access(handle,
4055 EXT4_SB(sb)->s_sbh);
4058 ext4_update_dynamic_rev(sb);
4059 EXT4_SET_RO_COMPAT_FEATURE(sb,
4060 EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
4063 err = ext4_journal_dirty_metadata(handle,
4064 EXT4_SB(sb)->s_sbh);
4067 raw_inode->i_generation = cpu_to_le32(inode->i_generation);
4068 if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
4069 if (old_valid_dev(inode->i_rdev)) {
4070 raw_inode->i_block[0] =
4071 cpu_to_le32(old_encode_dev(inode->i_rdev));
4072 raw_inode->i_block[1] = 0;
4074 raw_inode->i_block[0] = 0;
4075 raw_inode->i_block[1] =
4076 cpu_to_le32(new_encode_dev(inode->i_rdev));
4077 raw_inode->i_block[2] = 0;
4079 } else for (block = 0; block < EXT4_N_BLOCKS; block++)
4080 raw_inode->i_block[block] = ei->i_data[block];
4082 raw_inode->i_disk_version = cpu_to_le32(inode->i_version);
4083 if (ei->i_extra_isize) {
4084 if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi))
4085 raw_inode->i_version_hi =
4086 cpu_to_le32(inode->i_version >> 32);
4087 raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
4091 BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
4092 rc = ext4_journal_dirty_metadata(handle, bh);
4095 ei->i_state &= ~EXT4_STATE_NEW;
4099 ext4_std_error(inode->i_sb, err);
4104 * ext4_write_inode()
4106 * We are called from a few places:
4108 * - Within generic_file_write() for O_SYNC files.
4109 * Here, there will be no transaction running. We wait for any running
4110 * trasnaction to commit.
4112 * - Within sys_sync(), kupdate and such.
4113 * We wait on commit, if tol to.
4115 * - Within prune_icache() (PF_MEMALLOC == true)
4116 * Here we simply return. We can't afford to block kswapd on the
4119 * In all cases it is actually safe for us to return without doing anything,
4120 * because the inode has been copied into a raw inode buffer in
4121 * ext4_mark_inode_dirty(). This is a correctness thing for O_SYNC and for
4124 * Note that we are absolutely dependent upon all inode dirtiers doing the
4125 * right thing: they *must* call mark_inode_dirty() after dirtying info in
4126 * which we are interested.
4128 * It would be a bug for them to not do this. The code:
4130 * mark_inode_dirty(inode)
4132 * inode->i_size = expr;
4134 * is in error because a kswapd-driven write_inode() could occur while
4135 * `stuff()' is running, and the new i_size will be lost. Plus the inode
4136 * will no longer be on the superblock's dirty inode list.
4138 int ext4_write_inode(struct inode *inode, int wait)
4140 if (current->flags & PF_MEMALLOC)
4143 if (ext4_journal_current_handle()) {
4144 jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n");
4152 return ext4_force_commit(inode->i_sb);
4158 * Called from notify_change.
4160 * We want to trap VFS attempts to truncate the file as soon as
4161 * possible. In particular, we want to make sure that when the VFS
4162 * shrinks i_size, we put the inode on the orphan list and modify
4163 * i_disksize immediately, so that during the subsequent flushing of
4164 * dirty pages and freeing of disk blocks, we can guarantee that any
4165 * commit will leave the blocks being flushed in an unused state on
4166 * disk. (On recovery, the inode will get truncated and the blocks will
4167 * be freed, so we have a strong guarantee that no future commit will
4168 * leave these blocks visible to the user.)
4170 * Another thing we have to assure is that if we are in ordered mode
4171 * and inode is still attached to the committing transaction, we must
4172 * we start writeout of all the dirty pages which are being truncated.
4173 * This way we are sure that all the data written in the previous
4174 * transaction are already on disk (truncate waits for pages under
4177 * Called with inode->i_mutex down.
4179 int ext4_setattr(struct dentry *dentry, struct iattr *attr)
4181 struct inode *inode = dentry->d_inode;
4183 const unsigned int ia_valid = attr->ia_valid;
4185 error = inode_change_ok(inode, attr);
4189 if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
4190 (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) {
4193 /* (user+group)*(old+new) structure, inode write (sb,
4194 * inode block, ? - but truncate inode update has it) */
4195 handle = ext4_journal_start(inode, 2*(EXT4_QUOTA_INIT_BLOCKS(inode->i_sb)+
4196 EXT4_QUOTA_DEL_BLOCKS(inode->i_sb))+3);
4197 if (IS_ERR(handle)) {
4198 error = PTR_ERR(handle);
4201 error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
4203 ext4_journal_stop(handle);
4206 /* Update corresponding info in inode so that everything is in
4207 * one transaction */
4208 if (attr->ia_valid & ATTR_UID)
4209 inode->i_uid = attr->ia_uid;
4210 if (attr->ia_valid & ATTR_GID)
4211 inode->i_gid = attr->ia_gid;
4212 error = ext4_mark_inode_dirty(handle, inode);
4213 ext4_journal_stop(handle);
4216 if (attr->ia_valid & ATTR_SIZE) {
4217 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) {
4218 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4220 if (attr->ia_size > sbi->s_bitmap_maxbytes) {
4227 if (S_ISREG(inode->i_mode) &&
4228 attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
4231 handle = ext4_journal_start(inode, 3);
4232 if (IS_ERR(handle)) {
4233 error = PTR_ERR(handle);
4237 error = ext4_orphan_add(handle, inode);
4238 EXT4_I(inode)->i_disksize = attr->ia_size;
4239 rc = ext4_mark_inode_dirty(handle, inode);
4242 ext4_journal_stop(handle);
4244 if (ext4_should_order_data(inode)) {
4245 error = ext4_begin_ordered_truncate(inode,
4248 /* Do as much error cleanup as possible */
4249 handle = ext4_journal_start(inode, 3);
4250 if (IS_ERR(handle)) {
4251 ext4_orphan_del(NULL, inode);
4254 ext4_orphan_del(handle, inode);
4255 ext4_journal_stop(handle);
4261 rc = inode_setattr(inode, attr);
4263 /* If inode_setattr's call to ext4_truncate failed to get a
4264 * transaction handle at all, we need to clean up the in-core
4265 * orphan list manually. */
4267 ext4_orphan_del(NULL, inode);
4269 if (!rc && (ia_valid & ATTR_MODE))
4270 rc = ext4_acl_chmod(inode);
4273 ext4_std_error(inode->i_sb, error);
4279 int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
4282 struct inode *inode;
4283 unsigned long delalloc_blocks;
4285 inode = dentry->d_inode;
4286 generic_fillattr(inode, stat);
4289 * We can't update i_blocks if the block allocation is delayed
4290 * otherwise in the case of system crash before the real block
4291 * allocation is done, we will have i_blocks inconsistent with
4292 * on-disk file blocks.
4293 * We always keep i_blocks updated together with real
4294 * allocation. But to not confuse with user, stat
4295 * will return the blocks that include the delayed allocation
4296 * blocks for this file.
4298 spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
4299 delalloc_blocks = EXT4_I(inode)->i_reserved_data_blocks;
4300 spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
4302 stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9;
4307 * How many blocks doth make a writepage()?
4309 * With N blocks per page, it may be:
4314 * N+5 bitmap blocks (from the above)
4315 * N+5 group descriptor summary blocks
4318 * 2 * EXT4_SINGLEDATA_TRANS_BLOCKS for the quote files
4320 * 3 * (N + 5) + 2 + 2 * EXT4_SINGLEDATA_TRANS_BLOCKS
4322 * With ordered or writeback data it's the same, less the N data blocks.
4324 * If the inode's direct blocks can hold an integral number of pages then a
4325 * page cannot straddle two indirect blocks, and we can only touch one indirect
4326 * and dindirect block, and the "5" above becomes "3".
4328 * This still overestimates under most circumstances. If we were to pass the
4329 * start and end offsets in here as well we could do block_to_path() on each
4330 * block and work out the exact number of indirects which are touched. Pah.
4333 int ext4_writepage_trans_blocks(struct inode *inode)
4335 int bpp = ext4_journal_blocks_per_page(inode);
4336 int indirects = (EXT4_NDIR_BLOCKS % bpp) ? 5 : 3;
4339 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
4340 return ext4_ext_writepage_trans_blocks(inode, bpp);
4342 if (ext4_should_journal_data(inode))
4343 ret = 3 * (bpp + indirects) + 2;
4345 ret = 2 * (bpp + indirects) + 2;
4348 /* We know that structure was already allocated during DQUOT_INIT so
4349 * we will be updating only the data blocks + inodes */
4350 ret += 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
4357 * The caller must have previously called ext4_reserve_inode_write().
4358 * Give this, we know that the caller already has write access to iloc->bh.
4360 int ext4_mark_iloc_dirty(handle_t *handle,
4361 struct inode *inode, struct ext4_iloc *iloc)
4365 if (test_opt(inode->i_sb, I_VERSION))
4366 inode_inc_iversion(inode);
4368 /* the do_update_inode consumes one bh->b_count */
4371 /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
4372 err = ext4_do_update_inode(handle, inode, iloc);
4378 * On success, We end up with an outstanding reference count against
4379 * iloc->bh. This _must_ be cleaned up later.
4383 ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
4384 struct ext4_iloc *iloc)
4388 err = ext4_get_inode_loc(inode, iloc);
4390 BUFFER_TRACE(iloc->bh, "get_write_access");
4391 err = ext4_journal_get_write_access(handle, iloc->bh);
4398 ext4_std_error(inode->i_sb, err);
4403 * Expand an inode by new_extra_isize bytes.
4404 * Returns 0 on success or negative error number on failure.
4406 static int ext4_expand_extra_isize(struct inode *inode,
4407 unsigned int new_extra_isize,
4408 struct ext4_iloc iloc,
4411 struct ext4_inode *raw_inode;
4412 struct ext4_xattr_ibody_header *header;
4413 struct ext4_xattr_entry *entry;
4415 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize)
4418 raw_inode = ext4_raw_inode(&iloc);
4420 header = IHDR(inode, raw_inode);
4421 entry = IFIRST(header);
4423 /* No extended attributes present */
4424 if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR) ||
4425 header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) {
4426 memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0,
4428 EXT4_I(inode)->i_extra_isize = new_extra_isize;
4432 /* try to expand with EAs present */
4433 return ext4_expand_extra_isize_ea(inode, new_extra_isize,
4438 * What we do here is to mark the in-core inode as clean with respect to inode
4439 * dirtiness (it may still be data-dirty).
4440 * This means that the in-core inode may be reaped by prune_icache
4441 * without having to perform any I/O. This is a very good thing,
4442 * because *any* task may call prune_icache - even ones which
4443 * have a transaction open against a different journal.
4445 * Is this cheating? Not really. Sure, we haven't written the
4446 * inode out, but prune_icache isn't a user-visible syncing function.
4447 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
4448 * we start and wait on commits.
4450 * Is this efficient/effective? Well, we're being nice to the system
4451 * by cleaning up our inodes proactively so they can be reaped
4452 * without I/O. But we are potentially leaving up to five seconds'
4453 * worth of inodes floating about which prune_icache wants us to
4454 * write out. One way to fix that would be to get prune_icache()
4455 * to do a write_super() to free up some memory. It has the desired
4458 int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
4460 struct ext4_iloc iloc;
4461 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
4462 static unsigned int mnt_count;
4466 err = ext4_reserve_inode_write(handle, inode, &iloc);
4467 if (EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
4468 !(EXT4_I(inode)->i_state & EXT4_STATE_NO_EXPAND)) {
4470 * We need extra buffer credits since we may write into EA block
4471 * with this same handle. If journal_extend fails, then it will
4472 * only result in a minor loss of functionality for that inode.
4473 * If this is felt to be critical, then e2fsck should be run to
4474 * force a large enough s_min_extra_isize.
4476 if ((jbd2_journal_extend(handle,
4477 EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) {
4478 ret = ext4_expand_extra_isize(inode,
4479 sbi->s_want_extra_isize,
4482 EXT4_I(inode)->i_state |= EXT4_STATE_NO_EXPAND;
4484 le16_to_cpu(sbi->s_es->s_mnt_count)) {
4485 ext4_warning(inode->i_sb, __func__,
4486 "Unable to expand inode %lu. Delete"
4487 " some EAs or run e2fsck.",
4490 le16_to_cpu(sbi->s_es->s_mnt_count);
4496 err = ext4_mark_iloc_dirty(handle, inode, &iloc);
4501 * ext4_dirty_inode() is called from __mark_inode_dirty()
4503 * We're really interested in the case where a file is being extended.
4504 * i_size has been changed by generic_commit_write() and we thus need
4505 * to include the updated inode in the current transaction.
4507 * Also, DQUOT_ALLOC_SPACE() will always dirty the inode when blocks
4508 * are allocated to the file.
4510 * If the inode is marked synchronous, we don't honour that here - doing
4511 * so would cause a commit on atime updates, which we don't bother doing.
4512 * We handle synchronous inodes at the highest possible level.
4514 void ext4_dirty_inode(struct inode *inode)
4516 handle_t *current_handle = ext4_journal_current_handle();
4519 handle = ext4_journal_start(inode, 2);
4522 if (current_handle &&
4523 current_handle->h_transaction != handle->h_transaction) {
4524 /* This task has a transaction open against a different fs */
4525 printk(KERN_EMERG "%s: transactions do not match!\n",
4528 jbd_debug(5, "marking dirty. outer handle=%p\n",
4530 ext4_mark_inode_dirty(handle, inode);
4532 ext4_journal_stop(handle);
4539 * Bind an inode's backing buffer_head into this transaction, to prevent
4540 * it from being flushed to disk early. Unlike
4541 * ext4_reserve_inode_write, this leaves behind no bh reference and
4542 * returns no iloc structure, so the caller needs to repeat the iloc
4543 * lookup to mark the inode dirty later.
4545 static int ext4_pin_inode(handle_t *handle, struct inode *inode)
4547 struct ext4_iloc iloc;
4551 err = ext4_get_inode_loc(inode, &iloc);
4553 BUFFER_TRACE(iloc.bh, "get_write_access");
4554 err = jbd2_journal_get_write_access(handle, iloc.bh);
4556 err = ext4_journal_dirty_metadata(handle,
4561 ext4_std_error(inode->i_sb, err);
4566 int ext4_change_inode_journal_flag(struct inode *inode, int val)
4573 * We have to be very careful here: changing a data block's
4574 * journaling status dynamically is dangerous. If we write a
4575 * data block to the journal, change the status and then delete
4576 * that block, we risk forgetting to revoke the old log record
4577 * from the journal and so a subsequent replay can corrupt data.
4578 * So, first we make sure that the journal is empty and that
4579 * nobody is changing anything.
4582 journal = EXT4_JOURNAL(inode);
4583 if (is_journal_aborted(journal))
4586 jbd2_journal_lock_updates(journal);
4587 jbd2_journal_flush(journal);
4590 * OK, there are no updates running now, and all cached data is
4591 * synced to disk. We are now in a completely consistent state
4592 * which doesn't have anything in the journal, and we know that
4593 * no filesystem updates are running, so it is safe to modify
4594 * the inode's in-core data-journaling state flag now.
4598 EXT4_I(inode)->i_flags |= EXT4_JOURNAL_DATA_FL;
4600 EXT4_I(inode)->i_flags &= ~EXT4_JOURNAL_DATA_FL;
4601 ext4_set_aops(inode);
4603 jbd2_journal_unlock_updates(journal);
4605 /* Finally we can mark the inode as dirty. */
4607 handle = ext4_journal_start(inode, 1);
4609 return PTR_ERR(handle);
4611 err = ext4_mark_inode_dirty(handle, inode);
4613 ext4_journal_stop(handle);
4614 ext4_std_error(inode->i_sb, err);
4619 static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh)
4621 return !buffer_mapped(bh);
4624 int ext4_page_mkwrite(struct vm_area_struct *vma, struct page *page)
4629 struct file *file = vma->vm_file;
4630 struct inode *inode = file->f_path.dentry->d_inode;
4631 struct address_space *mapping = inode->i_mapping;
4634 * Get i_alloc_sem to stop truncates messing with the inode. We cannot
4635 * get i_mutex because we are already holding mmap_sem.
4637 down_read(&inode->i_alloc_sem);
4638 size = i_size_read(inode);
4639 if (page->mapping != mapping || size <= page_offset(page)
4640 || !PageUptodate(page)) {
4641 /* page got truncated from under us? */
4645 if (PageMappedToDisk(page))
4648 if (page->index == size >> PAGE_CACHE_SHIFT)
4649 len = size & ~PAGE_CACHE_MASK;
4651 len = PAGE_CACHE_SIZE;
4653 if (page_has_buffers(page)) {
4654 /* return if we have all the buffers mapped */
4655 if (!walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
4660 * OK, we need to fill the hole... Do write_begin write_end
4661 * to do block allocation/reservation.We are not holding
4662 * inode.i__mutex here. That allow * parallel write_begin,
4663 * write_end call. lock_page prevent this from happening
4664 * on the same page though
4666 ret = mapping->a_ops->write_begin(file, mapping, page_offset(page),
4667 len, AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
4670 ret = mapping->a_ops->write_end(file, mapping, page_offset(page),
4671 len, len, page, NULL);
4676 up_read(&inode->i_alloc_sem);