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1/*
2 * linux/fs/ext2/inode.c
3 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 *
9 * from
10 *
11 * linux/fs/minix/inode.c
12 *
13 * Copyright (C) 1991, 1992 Linus Torvalds
14 *
15 * Goal-directed block allocation by Stephen Tweedie
16 * (sct@dcs.ed.ac.uk), 1993, 1998
17 * Big-endian to little-endian byte-swapping/bitmaps by
18 * David S. Miller (davem@caip.rutgers.edu), 1995
19 * 64-bit file support on 64-bit platforms by Jakub Jelinek
20 * (jj@sunsite.ms.mff.cuni.cz)
21 *
22 * Assorted race fixes, rewrite of ext2_get_block() by Al Viro, 2000
23 */
24
25#include <linux/time.h>
26#include <linux/highuid.h>
27#include <linux/pagemap.h>
28#include <linux/dax.h>
29#include <linux/quotaops.h>
30#include <linux/writeback.h>
31#include <linux/buffer_head.h>
32#include <linux/mpage.h>
33#include <linux/fiemap.h>
34#include <linux/namei.h>
35#include <linux/uio.h>
36#include "ext2.h"
37#include "acl.h"
38#include "xattr.h"
39
40static int __ext2_write_inode(struct inode *inode, int do_sync);
41
42/*
43 * Test whether an inode is a fast symlink.
44 */
45static inline int ext2_inode_is_fast_symlink(struct inode *inode)
46{
47 int ea_blocks = EXT2_I(inode)->i_file_acl ?
48 (inode->i_sb->s_blocksize >> 9) : 0;
49
50 return (S_ISLNK(inode->i_mode) &&
51 inode->i_blocks - ea_blocks == 0);
52}
53
54static void ext2_truncate_blocks(struct inode *inode, loff_t offset);
55
56static void ext2_write_failed(struct address_space *mapping, loff_t to)
57{
58 struct inode *inode = mapping->host;
59
60 if (to > inode->i_size) {
61 truncate_pagecache(inode, inode->i_size);
62 ext2_truncate_blocks(inode, inode->i_size);
63 }
64}
65
66/*
67 * Called at the last iput() if i_nlink is zero.
68 */
69void ext2_evict_inode(struct inode * inode)
70{
71 struct ext2_block_alloc_info *rsv;
72 int want_delete = 0;
73
74 if (!inode->i_nlink && !is_bad_inode(inode)) {
75 want_delete = 1;
76 dquot_initialize(inode);
77 } else {
78 dquot_drop(inode);
79 }
80
81 truncate_inode_pages_final(&inode->i_data);
82
83 if (want_delete) {
84 sb_start_intwrite(inode->i_sb);
85 /* set dtime */
86 EXT2_I(inode)->i_dtime = get_seconds();
87 mark_inode_dirty(inode);
88 __ext2_write_inode(inode, inode_needs_sync(inode));
89 /* truncate to 0 */
90 inode->i_size = 0;
91 if (inode->i_blocks)
92 ext2_truncate_blocks(inode, 0);
93 ext2_xattr_delete_inode(inode);
94 }
95
96 invalidate_inode_buffers(inode);
97 clear_inode(inode);
98
99 ext2_discard_reservation(inode);
100 rsv = EXT2_I(inode)->i_block_alloc_info;
101 EXT2_I(inode)->i_block_alloc_info = NULL;
102 if (unlikely(rsv))
103 kfree(rsv);
104
105 if (want_delete) {
106 ext2_free_inode(inode);
107 sb_end_intwrite(inode->i_sb);
108 }
109}
110
111typedef struct {
112 __le32 *p;
113 __le32 key;
114 struct buffer_head *bh;
115} Indirect;
116
117static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
118{
119 p->key = *(p->p = v);
120 p->bh = bh;
121}
122
123static inline int verify_chain(Indirect *from, Indirect *to)
124{
125 while (from <= to && from->key == *from->p)
126 from++;
127 return (from > to);
128}
129
130/**
131 * ext2_block_to_path - parse the block number into array of offsets
132 * @inode: inode in question (we are only interested in its superblock)
133 * @i_block: block number to be parsed
134 * @offsets: array to store the offsets in
135 * @boundary: set this non-zero if the referred-to block is likely to be
136 * followed (on disk) by an indirect block.
137 * To store the locations of file's data ext2 uses a data structure common
138 * for UNIX filesystems - tree of pointers anchored in the inode, with
139 * data blocks at leaves and indirect blocks in intermediate nodes.
140 * This function translates the block number into path in that tree -
141 * return value is the path length and @offsets[n] is the offset of
142 * pointer to (n+1)th node in the nth one. If @block is out of range
143 * (negative or too large) warning is printed and zero returned.
144 *
145 * Note: function doesn't find node addresses, so no IO is needed. All
146 * we need to know is the capacity of indirect blocks (taken from the
147 * inode->i_sb).
148 */
149
150/*
151 * Portability note: the last comparison (check that we fit into triple
152 * indirect block) is spelled differently, because otherwise on an
153 * architecture with 32-bit longs and 8Kb pages we might get into trouble
154 * if our filesystem had 8Kb blocks. We might use long long, but that would
155 * kill us on x86. Oh, well, at least the sign propagation does not matter -
156 * i_block would have to be negative in the very beginning, so we would not
157 * get there at all.
158 */
159
160static int ext2_block_to_path(struct inode *inode,
161 long i_block, int offsets[4], int *boundary)
162{
163 int ptrs = EXT2_ADDR_PER_BLOCK(inode->i_sb);
164 int ptrs_bits = EXT2_ADDR_PER_BLOCK_BITS(inode->i_sb);
165 const long direct_blocks = EXT2_NDIR_BLOCKS,
166 indirect_blocks = ptrs,
167 double_blocks = (1 << (ptrs_bits * 2));
168 int n = 0;
169 int final = 0;
170
171 if (i_block < 0) {
172 ext2_msg(inode->i_sb, KERN_WARNING,
173 "warning: %s: block < 0", __func__);
174 } else if (i_block < direct_blocks) {
175 offsets[n++] = i_block;
176 final = direct_blocks;
177 } else if ( (i_block -= direct_blocks) < indirect_blocks) {
178 offsets[n++] = EXT2_IND_BLOCK;
179 offsets[n++] = i_block;
180 final = ptrs;
181 } else if ((i_block -= indirect_blocks) < double_blocks) {
182 offsets[n++] = EXT2_DIND_BLOCK;
183 offsets[n++] = i_block >> ptrs_bits;
184 offsets[n++] = i_block & (ptrs - 1);
185 final = ptrs;
186 } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
187 offsets[n++] = EXT2_TIND_BLOCK;
188 offsets[n++] = i_block >> (ptrs_bits * 2);
189 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
190 offsets[n++] = i_block & (ptrs - 1);
191 final = ptrs;
192 } else {
193 ext2_msg(inode->i_sb, KERN_WARNING,
194 "warning: %s: block is too big", __func__);
195 }
196 if (boundary)
197 *boundary = final - 1 - (i_block & (ptrs - 1));
198
199 return n;
200}
201
202/**
203 * ext2_get_branch - read the chain of indirect blocks leading to data
204 * @inode: inode in question
205 * @depth: depth of the chain (1 - direct pointer, etc.)
206 * @offsets: offsets of pointers in inode/indirect blocks
207 * @chain: place to store the result
208 * @err: here we store the error value
209 *
210 * Function fills the array of triples <key, p, bh> and returns %NULL
211 * if everything went OK or the pointer to the last filled triple
212 * (incomplete one) otherwise. Upon the return chain[i].key contains
213 * the number of (i+1)-th block in the chain (as it is stored in memory,
214 * i.e. little-endian 32-bit), chain[i].p contains the address of that
215 * number (it points into struct inode for i==0 and into the bh->b_data
216 * for i>0) and chain[i].bh points to the buffer_head of i-th indirect
217 * block for i>0 and NULL for i==0. In other words, it holds the block
218 * numbers of the chain, addresses they were taken from (and where we can
219 * verify that chain did not change) and buffer_heads hosting these
220 * numbers.
221 *
222 * Function stops when it stumbles upon zero pointer (absent block)
223 * (pointer to last triple returned, *@err == 0)
224 * or when it gets an IO error reading an indirect block
225 * (ditto, *@err == -EIO)
226 * or when it notices that chain had been changed while it was reading
227 * (ditto, *@err == -EAGAIN)
228 * or when it reads all @depth-1 indirect blocks successfully and finds
229 * the whole chain, all way to the data (returns %NULL, *err == 0).
230 */
231static Indirect *ext2_get_branch(struct inode *inode,
232 int depth,
233 int *offsets,
234 Indirect chain[4],
235 int *err)
236{
237 struct super_block *sb = inode->i_sb;
238 Indirect *p = chain;
239 struct buffer_head *bh;
240
241 *err = 0;
242 /* i_data is not going away, no lock needed */
243 add_chain (chain, NULL, EXT2_I(inode)->i_data + *offsets);
244 if (!p->key)
245 goto no_block;
246 while (--depth) {
247 bh = sb_bread(sb, le32_to_cpu(p->key));
248 if (!bh)
249 goto failure;
250 read_lock(&EXT2_I(inode)->i_meta_lock);
251 if (!verify_chain(chain, p))
252 goto changed;
253 add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
254 read_unlock(&EXT2_I(inode)->i_meta_lock);
255 if (!p->key)
256 goto no_block;
257 }
258 return NULL;
259
260changed:
261 read_unlock(&EXT2_I(inode)->i_meta_lock);
262 brelse(bh);
263 *err = -EAGAIN;
264 goto no_block;
265failure:
266 *err = -EIO;
267no_block:
268 return p;
269}
270
271/**
272 * ext2_find_near - find a place for allocation with sufficient locality
273 * @inode: owner
274 * @ind: descriptor of indirect block.
275 *
276 * This function returns the preferred place for block allocation.
277 * It is used when heuristic for sequential allocation fails.
278 * Rules are:
279 * + if there is a block to the left of our position - allocate near it.
280 * + if pointer will live in indirect block - allocate near that block.
281 * + if pointer will live in inode - allocate in the same cylinder group.
282 *
283 * In the latter case we colour the starting block by the callers PID to
284 * prevent it from clashing with concurrent allocations for a different inode
285 * in the same block group. The PID is used here so that functionally related
286 * files will be close-by on-disk.
287 *
288 * Caller must make sure that @ind is valid and will stay that way.
289 */
290
291static ext2_fsblk_t ext2_find_near(struct inode *inode, Indirect *ind)
292{
293 struct ext2_inode_info *ei = EXT2_I(inode);
294 __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
295 __le32 *p;
296 ext2_fsblk_t bg_start;
297 ext2_fsblk_t colour;
298
299 /* Try to find previous block */
300 for (p = ind->p - 1; p >= start; p--)
301 if (*p)
302 return le32_to_cpu(*p);
303
304 /* No such thing, so let's try location of indirect block */
305 if (ind->bh)
306 return ind->bh->b_blocknr;
307
308 /*
309 * It is going to be referred from inode itself? OK, just put it into
310 * the same cylinder group then.
311 */
312 bg_start = ext2_group_first_block_no(inode->i_sb, ei->i_block_group);
313 colour = (current->pid % 16) *
314 (EXT2_BLOCKS_PER_GROUP(inode->i_sb) / 16);
315 return bg_start + colour;
316}
317
318/**
319 * ext2_find_goal - find a preferred place for allocation.
320 * @inode: owner
321 * @block: block we want
322 * @partial: pointer to the last triple within a chain
323 *
324 * Returns preferred place for a block (the goal).
325 */
326
327static inline ext2_fsblk_t ext2_find_goal(struct inode *inode, long block,
328 Indirect *partial)
329{
330 struct ext2_block_alloc_info *block_i;
331
332 block_i = EXT2_I(inode)->i_block_alloc_info;
333
334 /*
335 * try the heuristic for sequential allocation,
336 * failing that at least try to get decent locality.
337 */
338 if (block_i && (block == block_i->last_alloc_logical_block + 1)
339 && (block_i->last_alloc_physical_block != 0)) {
340 return block_i->last_alloc_physical_block + 1;
341 }
342
343 return ext2_find_near(inode, partial);
344}
345
346/**
347 * ext2_blks_to_allocate: Look up the block map and count the number
348 * of direct blocks need to be allocated for the given branch.
349 *
350 * @branch: chain of indirect blocks
351 * @k: number of blocks need for indirect blocks
352 * @blks: number of data blocks to be mapped.
353 * @blocks_to_boundary: the offset in the indirect block
354 *
355 * return the total number of blocks to be allocate, including the
356 * direct and indirect blocks.
357 */
358static int
359ext2_blks_to_allocate(Indirect * branch, int k, unsigned long blks,
360 int blocks_to_boundary)
361{
362 unsigned long count = 0;
363
364 /*
365 * Simple case, [t,d]Indirect block(s) has not allocated yet
366 * then it's clear blocks on that path have not allocated
367 */
368 if (k > 0) {
369 /* right now don't hanel cross boundary allocation */
370 if (blks < blocks_to_boundary + 1)
371 count += blks;
372 else
373 count += blocks_to_boundary + 1;
374 return count;
375 }
376
377 count++;
378 while (count < blks && count <= blocks_to_boundary
379 && le32_to_cpu(*(branch[0].p + count)) == 0) {
380 count++;
381 }
382 return count;
383}
384
385/**
386 * ext2_alloc_blocks: multiple allocate blocks needed for a branch
387 * @indirect_blks: the number of blocks need to allocate for indirect
388 * blocks
389 *
390 * @new_blocks: on return it will store the new block numbers for
391 * the indirect blocks(if needed) and the first direct block,
392 * @blks: on return it will store the total number of allocated
393 * direct blocks
394 */
395static int ext2_alloc_blocks(struct inode *inode,
396 ext2_fsblk_t goal, int indirect_blks, int blks,
397 ext2_fsblk_t new_blocks[4], int *err)
398{
399 int target, i;
400 unsigned long count = 0;
401 int index = 0;
402 ext2_fsblk_t current_block = 0;
403 int ret = 0;
404
405 /*
406 * Here we try to allocate the requested multiple blocks at once,
407 * on a best-effort basis.
408 * To build a branch, we should allocate blocks for
409 * the indirect blocks(if not allocated yet), and at least
410 * the first direct block of this branch. That's the
411 * minimum number of blocks need to allocate(required)
412 */
413 target = blks + indirect_blks;
414
415 while (1) {
416 count = target;
417 /* allocating blocks for indirect blocks and direct blocks */
418 current_block = ext2_new_blocks(inode,goal,&count,err);
419 if (*err)
420 goto failed_out;
421
422 target -= count;
423 /* allocate blocks for indirect blocks */
424 while (index < indirect_blks && count) {
425 new_blocks[index++] = current_block++;
426 count--;
427 }
428
429 if (count > 0)
430 break;
431 }
432
433 /* save the new block number for the first direct block */
434 new_blocks[index] = current_block;
435
436 /* total number of blocks allocated for direct blocks */
437 ret = count;
438 *err = 0;
439 return ret;
440failed_out:
441 for (i = 0; i <index; i++)
442 ext2_free_blocks(inode, new_blocks[i], 1);
443 if (index)
444 mark_inode_dirty(inode);
445 return ret;
446}
447
448/**
449 * ext2_alloc_branch - allocate and set up a chain of blocks.
450 * @inode: owner
451 * @num: depth of the chain (number of blocks to allocate)
452 * @offsets: offsets (in the blocks) to store the pointers to next.
453 * @branch: place to store the chain in.
454 *
455 * This function allocates @num blocks, zeroes out all but the last one,
456 * links them into chain and (if we are synchronous) writes them to disk.
457 * In other words, it prepares a branch that can be spliced onto the
458 * inode. It stores the information about that chain in the branch[], in
459 * the same format as ext2_get_branch() would do. We are calling it after
460 * we had read the existing part of chain and partial points to the last
461 * triple of that (one with zero ->key). Upon the exit we have the same
462 * picture as after the successful ext2_get_block(), except that in one
463 * place chain is disconnected - *branch->p is still zero (we did not
464 * set the last link), but branch->key contains the number that should
465 * be placed into *branch->p to fill that gap.
466 *
467 * If allocation fails we free all blocks we've allocated (and forget
468 * their buffer_heads) and return the error value the from failed
469 * ext2_alloc_block() (normally -ENOSPC). Otherwise we set the chain
470 * as described above and return 0.
471 */
472
473static int ext2_alloc_branch(struct inode *inode,
474 int indirect_blks, int *blks, ext2_fsblk_t goal,
475 int *offsets, Indirect *branch)
476{
477 int blocksize = inode->i_sb->s_blocksize;
478 int i, n = 0;
479 int err = 0;
480 struct buffer_head *bh;
481 int num;
482 ext2_fsblk_t new_blocks[4];
483 ext2_fsblk_t current_block;
484
485 num = ext2_alloc_blocks(inode, goal, indirect_blks,
486 *blks, new_blocks, &err);
487 if (err)
488 return err;
489
490 branch[0].key = cpu_to_le32(new_blocks[0]);
491 /*
492 * metadata blocks and data blocks are allocated.
493 */
494 for (n = 1; n <= indirect_blks; n++) {
495 /*
496 * Get buffer_head for parent block, zero it out
497 * and set the pointer to new one, then send
498 * parent to disk.
499 */
500 bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
501 if (unlikely(!bh)) {
502 err = -ENOMEM;
503 goto failed;
504 }
505 branch[n].bh = bh;
506 lock_buffer(bh);
507 memset(bh->b_data, 0, blocksize);
508 branch[n].p = (__le32 *) bh->b_data + offsets[n];
509 branch[n].key = cpu_to_le32(new_blocks[n]);
510 *branch[n].p = branch[n].key;
511 if ( n == indirect_blks) {
512 current_block = new_blocks[n];
513 /*
514 * End of chain, update the last new metablock of
515 * the chain to point to the new allocated
516 * data blocks numbers
517 */
518 for (i=1; i < num; i++)
519 *(branch[n].p + i) = cpu_to_le32(++current_block);
520 }
521 set_buffer_uptodate(bh);
522 unlock_buffer(bh);
523 mark_buffer_dirty_inode(bh, inode);
524 /* We used to sync bh here if IS_SYNC(inode).
525 * But we now rely upon generic_write_sync()
526 * and b_inode_buffers. But not for directories.
527 */
528 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
529 sync_dirty_buffer(bh);
530 }
531 *blks = num;
532 return err;
533
534failed:
535 for (i = 1; i < n; i++)
536 bforget(branch[i].bh);
537 for (i = 0; i < indirect_blks; i++)
538 ext2_free_blocks(inode, new_blocks[i], 1);
539 ext2_free_blocks(inode, new_blocks[i], num);
540 return err;
541}
542
543/**
544 * ext2_splice_branch - splice the allocated branch onto inode.
545 * @inode: owner
546 * @block: (logical) number of block we are adding
547 * @where: location of missing link
548 * @num: number of indirect blocks we are adding
549 * @blks: number of direct blocks we are adding
550 *
551 * This function fills the missing link and does all housekeeping needed in
552 * inode (->i_blocks, etc.). In case of success we end up with the full
553 * chain to new block and return 0.
554 */
555static void ext2_splice_branch(struct inode *inode,
556 long block, Indirect *where, int num, int blks)
557{
558 int i;
559 struct ext2_block_alloc_info *block_i;
560 ext2_fsblk_t current_block;
561
562 block_i = EXT2_I(inode)->i_block_alloc_info;
563
564 /* XXX LOCKING probably should have i_meta_lock ?*/
565 /* That's it */
566
567 *where->p = where->key;
568
569 /*
570 * Update the host buffer_head or inode to point to more just allocated
571 * direct blocks blocks
572 */
573 if (num == 0 && blks > 1) {
574 current_block = le32_to_cpu(where->key) + 1;
575 for (i = 1; i < blks; i++)
576 *(where->p + i ) = cpu_to_le32(current_block++);
577 }
578
579 /*
580 * update the most recently allocated logical & physical block
581 * in i_block_alloc_info, to assist find the proper goal block for next
582 * allocation
583 */
584 if (block_i) {
585 block_i->last_alloc_logical_block = block + blks - 1;
586 block_i->last_alloc_physical_block =
587 le32_to_cpu(where[num].key) + blks - 1;
588 }
589
590 /* We are done with atomic stuff, now do the rest of housekeeping */
591
592 /* had we spliced it onto indirect block? */
593 if (where->bh)
594 mark_buffer_dirty_inode(where->bh, inode);
595
596 inode->i_ctime = CURRENT_TIME_SEC;
597 mark_inode_dirty(inode);
598}
599
600/*
601 * Allocation strategy is simple: if we have to allocate something, we will
602 * have to go the whole way to leaf. So let's do it before attaching anything
603 * to tree, set linkage between the newborn blocks, write them if sync is
604 * required, recheck the path, free and repeat if check fails, otherwise
605 * set the last missing link (that will protect us from any truncate-generated
606 * removals - all blocks on the path are immune now) and possibly force the
607 * write on the parent block.
608 * That has a nice additional property: no special recovery from the failed
609 * allocations is needed - we simply release blocks and do not touch anything
610 * reachable from inode.
611 *
612 * `handle' can be NULL if create == 0.
613 *
614 * return > 0, # of blocks mapped or allocated.
615 * return = 0, if plain lookup failed.
616 * return < 0, error case.
617 */
618static int ext2_get_blocks(struct inode *inode,
619 sector_t iblock, unsigned long maxblocks,
620 struct buffer_head *bh_result,
621 int create)
622{
623 int err = -EIO;
624 int offsets[4];
625 Indirect chain[4];
626 Indirect *partial;
627 ext2_fsblk_t goal;
628 int indirect_blks;
629 int blocks_to_boundary = 0;
630 int depth;
631 struct ext2_inode_info *ei = EXT2_I(inode);
632 int count = 0;
633 ext2_fsblk_t first_block = 0;
634
635 BUG_ON(maxblocks == 0);
636
637 depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
638
639 if (depth == 0)
640 return (err);
641
642 partial = ext2_get_branch(inode, depth, offsets, chain, &err);
643 /* Simplest case - block found, no allocation needed */
644 if (!partial) {
645 first_block = le32_to_cpu(chain[depth - 1].key);
646 clear_buffer_new(bh_result); /* What's this do? */
647 count++;
648 /*map more blocks*/
649 while (count < maxblocks && count <= blocks_to_boundary) {
650 ext2_fsblk_t blk;
651
652 if (!verify_chain(chain, chain + depth - 1)) {
653 /*
654 * Indirect block might be removed by
655 * truncate while we were reading it.
656 * Handling of that case: forget what we've
657 * got now, go to reread.
658 */
659 err = -EAGAIN;
660 count = 0;
661 break;
662 }
663 blk = le32_to_cpu(*(chain[depth-1].p + count));
664 if (blk == first_block + count)
665 count++;
666 else
667 break;
668 }
669 if (err != -EAGAIN)
670 goto got_it;
671 }
672
673 /* Next simple case - plain lookup or failed read of indirect block */
674 if (!create || err == -EIO)
675 goto cleanup;
676
677 mutex_lock(&ei->truncate_mutex);
678 /*
679 * If the indirect block is missing while we are reading
680 * the chain(ext2_get_branch() returns -EAGAIN err), or
681 * if the chain has been changed after we grab the semaphore,
682 * (either because another process truncated this branch, or
683 * another get_block allocated this branch) re-grab the chain to see if
684 * the request block has been allocated or not.
685 *
686 * Since we already block the truncate/other get_block
687 * at this point, we will have the current copy of the chain when we
688 * splice the branch into the tree.
689 */
690 if (err == -EAGAIN || !verify_chain(chain, partial)) {
691 while (partial > chain) {
692 brelse(partial->bh);
693 partial--;
694 }
695 partial = ext2_get_branch(inode, depth, offsets, chain, &err);
696 if (!partial) {
697 count++;
698 mutex_unlock(&ei->truncate_mutex);
699 if (err)
700 goto cleanup;
701 clear_buffer_new(bh_result);
702 goto got_it;
703 }
704 }
705
706 /*
707 * Okay, we need to do block allocation. Lazily initialize the block
708 * allocation info here if necessary
709 */
710 if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
711 ext2_init_block_alloc_info(inode);
712
713 goal = ext2_find_goal(inode, iblock, partial);
714
715 /* the number of blocks need to allocate for [d,t]indirect blocks */
716 indirect_blks = (chain + depth) - partial - 1;
717 /*
718 * Next look up the indirect map to count the totoal number of
719 * direct blocks to allocate for this branch.
720 */
721 count = ext2_blks_to_allocate(partial, indirect_blks,
722 maxblocks, blocks_to_boundary);
723 /*
724 * XXX ???? Block out ext2_truncate while we alter the tree
725 */
726 err = ext2_alloc_branch(inode, indirect_blks, &count, goal,
727 offsets + (partial - chain), partial);
728
729 if (err) {
730 mutex_unlock(&ei->truncate_mutex);
731 goto cleanup;
732 }
733
734 if (IS_DAX(inode)) {
735 /*
736 * block must be initialised before we put it in the tree
737 * so that it's not found by another thread before it's
738 * initialised
739 */
740 err = dax_clear_sectors(inode->i_sb->s_bdev,
741 le32_to_cpu(chain[depth-1].key) <<
742 (inode->i_blkbits - 9),
743 1 << inode->i_blkbits);
744 if (err) {
745 mutex_unlock(&ei->truncate_mutex);
746 goto cleanup;
747 }
748 }
749
750 ext2_splice_branch(inode, iblock, partial, indirect_blks, count);
751 mutex_unlock(&ei->truncate_mutex);
752 set_buffer_new(bh_result);
753got_it:
754 map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
755 if (count > blocks_to_boundary)
756 set_buffer_boundary(bh_result);
757 err = count;
758 /* Clean up and exit */
759 partial = chain + depth - 1; /* the whole chain */
760cleanup:
761 while (partial > chain) {
762 brelse(partial->bh);
763 partial--;
764 }
765 return err;
766}
767
768int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
769{
770 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
771 int ret = ext2_get_blocks(inode, iblock, max_blocks,
772 bh_result, create);
773 if (ret > 0) {
774 bh_result->b_size = (ret << inode->i_blkbits);
775 ret = 0;
776 }
777 return ret;
778
779}
780
781int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
782 u64 start, u64 len)
783{
784 return generic_block_fiemap(inode, fieinfo, start, len,
785 ext2_get_block);
786}
787
788static int ext2_writepage(struct page *page, struct writeback_control *wbc)
789{
790 return block_write_full_page(page, ext2_get_block, wbc);
791}
792
793static int ext2_readpage(struct file *file, struct page *page)
794{
795 return mpage_readpage(page, ext2_get_block);
796}
797
798static int
799ext2_readpages(struct file *file, struct address_space *mapping,
800 struct list_head *pages, unsigned nr_pages)
801{
802 return mpage_readpages(mapping, pages, nr_pages, ext2_get_block);
803}
804
805static int
806ext2_write_begin(struct file *file, struct address_space *mapping,
807 loff_t pos, unsigned len, unsigned flags,
808 struct page **pagep, void **fsdata)
809{
810 int ret;
811
812 ret = block_write_begin(mapping, pos, len, flags, pagep,
813 ext2_get_block);
814 if (ret < 0)
815 ext2_write_failed(mapping, pos + len);
816 return ret;
817}
818
819static int ext2_write_end(struct file *file, struct address_space *mapping,
820 loff_t pos, unsigned len, unsigned copied,
821 struct page *page, void *fsdata)
822{
823 int ret;
824
825 ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
826 if (ret < len)
827 ext2_write_failed(mapping, pos + len);
828 return ret;
829}
830
831static int
832ext2_nobh_write_begin(struct file *file, struct address_space *mapping,
833 loff_t pos, unsigned len, unsigned flags,
834 struct page **pagep, void **fsdata)
835{
836 int ret;
837
838 ret = nobh_write_begin(mapping, pos, len, flags, pagep, fsdata,
839 ext2_get_block);
840 if (ret < 0)
841 ext2_write_failed(mapping, pos + len);
842 return ret;
843}
844
845static int ext2_nobh_writepage(struct page *page,
846 struct writeback_control *wbc)
847{
848 return nobh_writepage(page, ext2_get_block, wbc);
849}
850
851static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
852{
853 return generic_block_bmap(mapping,block,ext2_get_block);
854}
855
856static ssize_t
857ext2_direct_IO(struct kiocb *iocb, struct iov_iter *iter, loff_t offset)
858{
859 struct file *file = iocb->ki_filp;
860 struct address_space *mapping = file->f_mapping;
861 struct inode *inode = mapping->host;
862 size_t count = iov_iter_count(iter);
863 ssize_t ret;
864
865 if (IS_DAX(inode))
866 ret = dax_do_io(iocb, inode, iter, offset, ext2_get_block, NULL,
867 DIO_LOCKING);
868 else
869 ret = blockdev_direct_IO(iocb, inode, iter, offset,
870 ext2_get_block);
871 if (ret < 0 && iov_iter_rw(iter) == WRITE)
872 ext2_write_failed(mapping, offset + count);
873 return ret;
874}
875
876static int
877ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
878{
879#ifdef CONFIG_FS_DAX
880 if (dax_mapping(mapping)) {
881 return dax_writeback_mapping_range(mapping,
882 mapping->host->i_sb->s_bdev,
883 wbc);
884 }
885#endif
886
887 return mpage_writepages(mapping, wbc, ext2_get_block);
888}
889
890const struct address_space_operations ext2_aops = {
891 .readpage = ext2_readpage,
892 .readpages = ext2_readpages,
893 .writepage = ext2_writepage,
894 .write_begin = ext2_write_begin,
895 .write_end = ext2_write_end,
896 .bmap = ext2_bmap,
897 .direct_IO = ext2_direct_IO,
898 .writepages = ext2_writepages,
899 .migratepage = buffer_migrate_page,
900 .is_partially_uptodate = block_is_partially_uptodate,
901 .error_remove_page = generic_error_remove_page,
902};
903
904const struct address_space_operations ext2_nobh_aops = {
905 .readpage = ext2_readpage,
906 .readpages = ext2_readpages,
907 .writepage = ext2_nobh_writepage,
908 .write_begin = ext2_nobh_write_begin,
909 .write_end = nobh_write_end,
910 .bmap = ext2_bmap,
911 .direct_IO = ext2_direct_IO,
912 .writepages = ext2_writepages,
913 .migratepage = buffer_migrate_page,
914 .error_remove_page = generic_error_remove_page,
915};
916
917/*
918 * Probably it should be a library function... search for first non-zero word
919 * or memcmp with zero_page, whatever is better for particular architecture.
920 * Linus?
921 */
922static inline int all_zeroes(__le32 *p, __le32 *q)
923{
924 while (p < q)
925 if (*p++)
926 return 0;
927 return 1;
928}
929
930/**
931 * ext2_find_shared - find the indirect blocks for partial truncation.
932 * @inode: inode in question
933 * @depth: depth of the affected branch
934 * @offsets: offsets of pointers in that branch (see ext2_block_to_path)
935 * @chain: place to store the pointers to partial indirect blocks
936 * @top: place to the (detached) top of branch
937 *
938 * This is a helper function used by ext2_truncate().
939 *
940 * When we do truncate() we may have to clean the ends of several indirect
941 * blocks but leave the blocks themselves alive. Block is partially
942 * truncated if some data below the new i_size is referred from it (and
943 * it is on the path to the first completely truncated data block, indeed).
944 * We have to free the top of that path along with everything to the right
945 * of the path. Since no allocation past the truncation point is possible
946 * until ext2_truncate() finishes, we may safely do the latter, but top
947 * of branch may require special attention - pageout below the truncation
948 * point might try to populate it.
949 *
950 * We atomically detach the top of branch from the tree, store the block
951 * number of its root in *@top, pointers to buffer_heads of partially
952 * truncated blocks - in @chain[].bh and pointers to their last elements
953 * that should not be removed - in @chain[].p. Return value is the pointer
954 * to last filled element of @chain.
955 *
956 * The work left to caller to do the actual freeing of subtrees:
957 * a) free the subtree starting from *@top
958 * b) free the subtrees whose roots are stored in
959 * (@chain[i].p+1 .. end of @chain[i].bh->b_data)
960 * c) free the subtrees growing from the inode past the @chain[0].p
961 * (no partially truncated stuff there).
962 */
963
964static Indirect *ext2_find_shared(struct inode *inode,
965 int depth,
966 int offsets[4],
967 Indirect chain[4],
968 __le32 *top)
969{
970 Indirect *partial, *p;
971 int k, err;
972
973 *top = 0;
974 for (k = depth; k > 1 && !offsets[k-1]; k--)
975 ;
976 partial = ext2_get_branch(inode, k, offsets, chain, &err);
977 if (!partial)
978 partial = chain + k-1;
979 /*
980 * If the branch acquired continuation since we've looked at it -
981 * fine, it should all survive and (new) top doesn't belong to us.
982 */
983 write_lock(&EXT2_I(inode)->i_meta_lock);
984 if (!partial->key && *partial->p) {
985 write_unlock(&EXT2_I(inode)->i_meta_lock);
986 goto no_top;
987 }
988 for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
989 ;
990 /*
991 * OK, we've found the last block that must survive. The rest of our
992 * branch should be detached before unlocking. However, if that rest
993 * of branch is all ours and does not grow immediately from the inode
994 * it's easier to cheat and just decrement partial->p.
995 */
996 if (p == chain + k - 1 && p > chain) {
997 p->p--;
998 } else {
999 *top = *p->p;
1000 *p->p = 0;
1001 }
1002 write_unlock(&EXT2_I(inode)->i_meta_lock);
1003
1004 while(partial > p)
1005 {
1006 brelse(partial->bh);
1007 partial--;
1008 }
1009no_top:
1010 return partial;
1011}
1012
1013/**
1014 * ext2_free_data - free a list of data blocks
1015 * @inode: inode we are dealing with
1016 * @p: array of block numbers
1017 * @q: points immediately past the end of array
1018 *
1019 * We are freeing all blocks referred from that array (numbers are
1020 * stored as little-endian 32-bit) and updating @inode->i_blocks
1021 * appropriately.
1022 */
1023static inline void ext2_free_data(struct inode *inode, __le32 *p, __le32 *q)
1024{
1025 unsigned long block_to_free = 0, count = 0;
1026 unsigned long nr;
1027
1028 for ( ; p < q ; p++) {
1029 nr = le32_to_cpu(*p);
1030 if (nr) {
1031 *p = 0;
1032 /* accumulate blocks to free if they're contiguous */
1033 if (count == 0)
1034 goto free_this;
1035 else if (block_to_free == nr - count)
1036 count++;
1037 else {
1038 ext2_free_blocks (inode, block_to_free, count);
1039 mark_inode_dirty(inode);
1040 free_this:
1041 block_to_free = nr;
1042 count = 1;
1043 }
1044 }
1045 }
1046 if (count > 0) {
1047 ext2_free_blocks (inode, block_to_free, count);
1048 mark_inode_dirty(inode);
1049 }
1050}
1051
1052/**
1053 * ext2_free_branches - free an array of branches
1054 * @inode: inode we are dealing with
1055 * @p: array of block numbers
1056 * @q: pointer immediately past the end of array
1057 * @depth: depth of the branches to free
1058 *
1059 * We are freeing all blocks referred from these branches (numbers are
1060 * stored as little-endian 32-bit) and updating @inode->i_blocks
1061 * appropriately.
1062 */
1063static void ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int depth)
1064{
1065 struct buffer_head * bh;
1066 unsigned long nr;
1067
1068 if (depth--) {
1069 int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1070 for ( ; p < q ; p++) {
1071 nr = le32_to_cpu(*p);
1072 if (!nr)
1073 continue;
1074 *p = 0;
1075 bh = sb_bread(inode->i_sb, nr);
1076 /*
1077 * A read failure? Report error and clear slot
1078 * (should be rare).
1079 */
1080 if (!bh) {
1081 ext2_error(inode->i_sb, "ext2_free_branches",
1082 "Read failure, inode=%ld, block=%ld",
1083 inode->i_ino, nr);
1084 continue;
1085 }
1086 ext2_free_branches(inode,
1087 (__le32*)bh->b_data,
1088 (__le32*)bh->b_data + addr_per_block,
1089 depth);
1090 bforget(bh);
1091 ext2_free_blocks(inode, nr, 1);
1092 mark_inode_dirty(inode);
1093 }
1094 } else
1095 ext2_free_data(inode, p, q);
1096}
1097
1098/* dax_sem must be held when calling this function */
1099static void __ext2_truncate_blocks(struct inode *inode, loff_t offset)
1100{
1101 __le32 *i_data = EXT2_I(inode)->i_data;
1102 struct ext2_inode_info *ei = EXT2_I(inode);
1103 int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1104 int offsets[4];
1105 Indirect chain[4];
1106 Indirect *partial;
1107 __le32 nr = 0;
1108 int n;
1109 long iblock;
1110 unsigned blocksize;
1111 blocksize = inode->i_sb->s_blocksize;
1112 iblock = (offset + blocksize-1) >> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
1113
1114#ifdef CONFIG_FS_DAX
1115 WARN_ON(!rwsem_is_locked(&ei->dax_sem));
1116#endif
1117
1118 n = ext2_block_to_path(inode, iblock, offsets, NULL);
1119 if (n == 0)
1120 return;
1121
1122 /*
1123 * From here we block out all ext2_get_block() callers who want to
1124 * modify the block allocation tree.
1125 */
1126 mutex_lock(&ei->truncate_mutex);
1127
1128 if (n == 1) {
1129 ext2_free_data(inode, i_data+offsets[0],
1130 i_data + EXT2_NDIR_BLOCKS);
1131 goto do_indirects;
1132 }
1133
1134 partial = ext2_find_shared(inode, n, offsets, chain, &nr);
1135 /* Kill the top of shared branch (already detached) */
1136 if (nr) {
1137 if (partial == chain)
1138 mark_inode_dirty(inode);
1139 else
1140 mark_buffer_dirty_inode(partial->bh, inode);
1141 ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
1142 }
1143 /* Clear the ends of indirect blocks on the shared branch */
1144 while (partial > chain) {
1145 ext2_free_branches(inode,
1146 partial->p + 1,
1147 (__le32*)partial->bh->b_data+addr_per_block,
1148 (chain+n-1) - partial);
1149 mark_buffer_dirty_inode(partial->bh, inode);
1150 brelse (partial->bh);
1151 partial--;
1152 }
1153do_indirects:
1154 /* Kill the remaining (whole) subtrees */
1155 switch (offsets[0]) {
1156 default:
1157 nr = i_data[EXT2_IND_BLOCK];
1158 if (nr) {
1159 i_data[EXT2_IND_BLOCK] = 0;
1160 mark_inode_dirty(inode);
1161 ext2_free_branches(inode, &nr, &nr+1, 1);
1162 }
1163 case EXT2_IND_BLOCK:
1164 nr = i_data[EXT2_DIND_BLOCK];
1165 if (nr) {
1166 i_data[EXT2_DIND_BLOCK] = 0;
1167 mark_inode_dirty(inode);
1168 ext2_free_branches(inode, &nr, &nr+1, 2);
1169 }
1170 case EXT2_DIND_BLOCK:
1171 nr = i_data[EXT2_TIND_BLOCK];
1172 if (nr) {
1173 i_data[EXT2_TIND_BLOCK] = 0;
1174 mark_inode_dirty(inode);
1175 ext2_free_branches(inode, &nr, &nr+1, 3);
1176 }
1177 case EXT2_TIND_BLOCK:
1178 ;
1179 }
1180
1181 ext2_discard_reservation(inode);
1182
1183 mutex_unlock(&ei->truncate_mutex);
1184}
1185
1186static void ext2_truncate_blocks(struct inode *inode, loff_t offset)
1187{
1188 /*
1189 * XXX: it seems like a bug here that we don't allow
1190 * IS_APPEND inode to have blocks-past-i_size trimmed off.
1191 * review and fix this.
1192 *
1193 * Also would be nice to be able to handle IO errors and such,
1194 * but that's probably too much to ask.
1195 */
1196 if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1197 S_ISLNK(inode->i_mode)))
1198 return;
1199 if (ext2_inode_is_fast_symlink(inode))
1200 return;
1201 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1202 return;
1203
1204 dax_sem_down_write(EXT2_I(inode));
1205 __ext2_truncate_blocks(inode, offset);
1206 dax_sem_up_write(EXT2_I(inode));
1207}
1208
1209static int ext2_setsize(struct inode *inode, loff_t newsize)
1210{
1211 int error;
1212
1213 if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1214 S_ISLNK(inode->i_mode)))
1215 return -EINVAL;
1216 if (ext2_inode_is_fast_symlink(inode))
1217 return -EINVAL;
1218 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1219 return -EPERM;
1220
1221 inode_dio_wait(inode);
1222
1223 if (IS_DAX(inode))
1224 error = dax_truncate_page(inode, newsize, ext2_get_block);
1225 else if (test_opt(inode->i_sb, NOBH))
1226 error = nobh_truncate_page(inode->i_mapping,
1227 newsize, ext2_get_block);
1228 else
1229 error = block_truncate_page(inode->i_mapping,
1230 newsize, ext2_get_block);
1231 if (error)
1232 return error;
1233
1234 dax_sem_down_write(EXT2_I(inode));
1235 truncate_setsize(inode, newsize);
1236 __ext2_truncate_blocks(inode, newsize);
1237 dax_sem_up_write(EXT2_I(inode));
1238
1239 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
1240 if (inode_needs_sync(inode)) {
1241 sync_mapping_buffers(inode->i_mapping);
1242 sync_inode_metadata(inode, 1);
1243 } else {
1244 mark_inode_dirty(inode);
1245 }
1246
1247 return 0;
1248}
1249
1250static struct ext2_inode *ext2_get_inode(struct super_block *sb, ino_t ino,
1251 struct buffer_head **p)
1252{
1253 struct buffer_head * bh;
1254 unsigned long block_group;
1255 unsigned long block;
1256 unsigned long offset;
1257 struct ext2_group_desc * gdp;
1258
1259 *p = NULL;
1260 if ((ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) ||
1261 ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
1262 goto Einval;
1263
1264 block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
1265 gdp = ext2_get_group_desc(sb, block_group, NULL);
1266 if (!gdp)
1267 goto Egdp;
1268 /*
1269 * Figure out the offset within the block group inode table
1270 */
1271 offset = ((ino - 1) % EXT2_INODES_PER_GROUP(sb)) * EXT2_INODE_SIZE(sb);
1272 block = le32_to_cpu(gdp->bg_inode_table) +
1273 (offset >> EXT2_BLOCK_SIZE_BITS(sb));
1274 if (!(bh = sb_bread(sb, block)))
1275 goto Eio;
1276
1277 *p = bh;
1278 offset &= (EXT2_BLOCK_SIZE(sb) - 1);
1279 return (struct ext2_inode *) (bh->b_data + offset);
1280
1281Einval:
1282 ext2_error(sb, "ext2_get_inode", "bad inode number: %lu",
1283 (unsigned long) ino);
1284 return ERR_PTR(-EINVAL);
1285Eio:
1286 ext2_error(sb, "ext2_get_inode",
1287 "unable to read inode block - inode=%lu, block=%lu",
1288 (unsigned long) ino, block);
1289Egdp:
1290 return ERR_PTR(-EIO);
1291}
1292
1293void ext2_set_inode_flags(struct inode *inode)
1294{
1295 unsigned int flags = EXT2_I(inode)->i_flags;
1296
1297 inode->i_flags &= ~(S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME |
1298 S_DIRSYNC | S_DAX);
1299 if (flags & EXT2_SYNC_FL)
1300 inode->i_flags |= S_SYNC;
1301 if (flags & EXT2_APPEND_FL)
1302 inode->i_flags |= S_APPEND;
1303 if (flags & EXT2_IMMUTABLE_FL)
1304 inode->i_flags |= S_IMMUTABLE;
1305 if (flags & EXT2_NOATIME_FL)
1306 inode->i_flags |= S_NOATIME;
1307 if (flags & EXT2_DIRSYNC_FL)
1308 inode->i_flags |= S_DIRSYNC;
1309 if (test_opt(inode->i_sb, DAX) && S_ISREG(inode->i_mode))
1310 inode->i_flags |= S_DAX;
1311}
1312
1313/* Propagate flags from i_flags to EXT2_I(inode)->i_flags */
1314void ext2_get_inode_flags(struct ext2_inode_info *ei)
1315{
1316 unsigned int flags = ei->vfs_inode.i_flags;
1317
1318 ei->i_flags &= ~(EXT2_SYNC_FL|EXT2_APPEND_FL|
1319 EXT2_IMMUTABLE_FL|EXT2_NOATIME_FL|EXT2_DIRSYNC_FL);
1320 if (flags & S_SYNC)
1321 ei->i_flags |= EXT2_SYNC_FL;
1322 if (flags & S_APPEND)
1323 ei->i_flags |= EXT2_APPEND_FL;
1324 if (flags & S_IMMUTABLE)
1325 ei->i_flags |= EXT2_IMMUTABLE_FL;
1326 if (flags & S_NOATIME)
1327 ei->i_flags |= EXT2_NOATIME_FL;
1328 if (flags & S_DIRSYNC)
1329 ei->i_flags |= EXT2_DIRSYNC_FL;
1330}
1331
1332struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
1333{
1334 struct ext2_inode_info *ei;
1335 struct buffer_head * bh;
1336 struct ext2_inode *raw_inode;
1337 struct inode *inode;
1338 long ret = -EIO;
1339 int n;
1340 uid_t i_uid;
1341 gid_t i_gid;
1342
1343 inode = iget_locked(sb, ino);
1344 if (!inode)
1345 return ERR_PTR(-ENOMEM);
1346 if (!(inode->i_state & I_NEW))
1347 return inode;
1348
1349 ei = EXT2_I(inode);
1350 ei->i_block_alloc_info = NULL;
1351
1352 raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
1353 if (IS_ERR(raw_inode)) {
1354 ret = PTR_ERR(raw_inode);
1355 goto bad_inode;
1356 }
1357
1358 inode->i_mode = le16_to_cpu(raw_inode->i_mode);
1359 i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
1360 i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
1361 if (!(test_opt (inode->i_sb, NO_UID32))) {
1362 i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
1363 i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
1364 }
1365 i_uid_write(inode, i_uid);
1366 i_gid_write(inode, i_gid);
1367 set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
1368 inode->i_size = le32_to_cpu(raw_inode->i_size);
1369 inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
1370 inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
1371 inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
1372 inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1373 ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
1374 /* We now have enough fields to check if the inode was active or not.
1375 * This is needed because nfsd might try to access dead inodes
1376 * the test is that same one that e2fsck uses
1377 * NeilBrown 1999oct15
1378 */
1379 if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
1380 /* this inode is deleted */
1381 brelse (bh);
1382 ret = -ESTALE;
1383 goto bad_inode;
1384 }
1385 inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
1386 ei->i_flags = le32_to_cpu(raw_inode->i_flags);
1387 ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
1388 ei->i_frag_no = raw_inode->i_frag;
1389 ei->i_frag_size = raw_inode->i_fsize;
1390 ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
1391 ei->i_dir_acl = 0;
1392 if (S_ISREG(inode->i_mode))
1393 inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
1394 else
1395 ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
1396 ei->i_dtime = 0;
1397 inode->i_generation = le32_to_cpu(raw_inode->i_generation);
1398 ei->i_state = 0;
1399 ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
1400 ei->i_dir_start_lookup = 0;
1401
1402 /*
1403 * NOTE! The in-memory inode i_data array is in little-endian order
1404 * even on big-endian machines: we do NOT byteswap the block numbers!
1405 */
1406 for (n = 0; n < EXT2_N_BLOCKS; n++)
1407 ei->i_data[n] = raw_inode->i_block[n];
1408
1409 if (S_ISREG(inode->i_mode)) {
1410 inode->i_op = &ext2_file_inode_operations;
1411 if (test_opt(inode->i_sb, NOBH)) {
1412 inode->i_mapping->a_ops = &ext2_nobh_aops;
1413 inode->i_fop = &ext2_file_operations;
1414 } else {
1415 inode->i_mapping->a_ops = &ext2_aops;
1416 inode->i_fop = &ext2_file_operations;
1417 }
1418 } else if (S_ISDIR(inode->i_mode)) {
1419 inode->i_op = &ext2_dir_inode_operations;
1420 inode->i_fop = &ext2_dir_operations;
1421 if (test_opt(inode->i_sb, NOBH))
1422 inode->i_mapping->a_ops = &ext2_nobh_aops;
1423 else
1424 inode->i_mapping->a_ops = &ext2_aops;
1425 } else if (S_ISLNK(inode->i_mode)) {
1426 if (ext2_inode_is_fast_symlink(inode)) {
1427 inode->i_link = (char *)ei->i_data;
1428 inode->i_op = &ext2_fast_symlink_inode_operations;
1429 nd_terminate_link(ei->i_data, inode->i_size,
1430 sizeof(ei->i_data) - 1);
1431 } else {
1432 inode->i_op = &ext2_symlink_inode_operations;
1433 inode_nohighmem(inode);
1434 if (test_opt(inode->i_sb, NOBH))
1435 inode->i_mapping->a_ops = &ext2_nobh_aops;
1436 else
1437 inode->i_mapping->a_ops = &ext2_aops;
1438 }
1439 } else {
1440 inode->i_op = &ext2_special_inode_operations;
1441 if (raw_inode->i_block[0])
1442 init_special_inode(inode, inode->i_mode,
1443 old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
1444 else
1445 init_special_inode(inode, inode->i_mode,
1446 new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
1447 }
1448 brelse (bh);
1449 ext2_set_inode_flags(inode);
1450 unlock_new_inode(inode);
1451 return inode;
1452
1453bad_inode:
1454 iget_failed(inode);
1455 return ERR_PTR(ret);
1456}
1457
1458static int __ext2_write_inode(struct inode *inode, int do_sync)
1459{
1460 struct ext2_inode_info *ei = EXT2_I(inode);
1461 struct super_block *sb = inode->i_sb;
1462 ino_t ino = inode->i_ino;
1463 uid_t uid = i_uid_read(inode);
1464 gid_t gid = i_gid_read(inode);
1465 struct buffer_head * bh;
1466 struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
1467 int n;
1468 int err = 0;
1469
1470 if (IS_ERR(raw_inode))
1471 return -EIO;
1472
1473 /* For fields not not tracking in the in-memory inode,
1474 * initialise them to zero for new inodes. */
1475 if (ei->i_state & EXT2_STATE_NEW)
1476 memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size);
1477
1478 ext2_get_inode_flags(ei);
1479 raw_inode->i_mode = cpu_to_le16(inode->i_mode);
1480 if (!(test_opt(sb, NO_UID32))) {
1481 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
1482 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(gid));
1483/*
1484 * Fix up interoperability with old kernels. Otherwise, old inodes get
1485 * re-used with the upper 16 bits of the uid/gid intact
1486 */
1487 if (!ei->i_dtime) {
1488 raw_inode->i_uid_high = cpu_to_le16(high_16_bits(uid));
1489 raw_inode->i_gid_high = cpu_to_le16(high_16_bits(gid));
1490 } else {
1491 raw_inode->i_uid_high = 0;
1492 raw_inode->i_gid_high = 0;
1493 }
1494 } else {
1495 raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(uid));
1496 raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid));
1497 raw_inode->i_uid_high = 0;
1498 raw_inode->i_gid_high = 0;
1499 }
1500 raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
1501 raw_inode->i_size = cpu_to_le32(inode->i_size);
1502 raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
1503 raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
1504 raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
1505
1506 raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
1507 raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
1508 raw_inode->i_flags = cpu_to_le32(ei->i_flags);
1509 raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
1510 raw_inode->i_frag = ei->i_frag_no;
1511 raw_inode->i_fsize = ei->i_frag_size;
1512 raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
1513 if (!S_ISREG(inode->i_mode))
1514 raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
1515 else {
1516 raw_inode->i_size_high = cpu_to_le32(inode->i_size >> 32);
1517 if (inode->i_size > 0x7fffffffULL) {
1518 if (!EXT2_HAS_RO_COMPAT_FEATURE(sb,
1519 EXT2_FEATURE_RO_COMPAT_LARGE_FILE) ||
1520 EXT2_SB(sb)->s_es->s_rev_level ==
1521 cpu_to_le32(EXT2_GOOD_OLD_REV)) {
1522 /* If this is the first large file
1523 * created, add a flag to the superblock.
1524 */
1525 spin_lock(&EXT2_SB(sb)->s_lock);
1526 ext2_update_dynamic_rev(sb);
1527 EXT2_SET_RO_COMPAT_FEATURE(sb,
1528 EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
1529 spin_unlock(&EXT2_SB(sb)->s_lock);
1530 ext2_write_super(sb);
1531 }
1532 }
1533 }
1534
1535 raw_inode->i_generation = cpu_to_le32(inode->i_generation);
1536 if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
1537 if (old_valid_dev(inode->i_rdev)) {
1538 raw_inode->i_block[0] =
1539 cpu_to_le32(old_encode_dev(inode->i_rdev));
1540 raw_inode->i_block[1] = 0;
1541 } else {
1542 raw_inode->i_block[0] = 0;
1543 raw_inode->i_block[1] =
1544 cpu_to_le32(new_encode_dev(inode->i_rdev));
1545 raw_inode->i_block[2] = 0;
1546 }
1547 } else for (n = 0; n < EXT2_N_BLOCKS; n++)
1548 raw_inode->i_block[n] = ei->i_data[n];
1549 mark_buffer_dirty(bh);
1550 if (do_sync) {
1551 sync_dirty_buffer(bh);
1552 if (buffer_req(bh) && !buffer_uptodate(bh)) {
1553 printk ("IO error syncing ext2 inode [%s:%08lx]\n",
1554 sb->s_id, (unsigned long) ino);
1555 err = -EIO;
1556 }
1557 }
1558 ei->i_state &= ~EXT2_STATE_NEW;
1559 brelse (bh);
1560 return err;
1561}
1562
1563int ext2_write_inode(struct inode *inode, struct writeback_control *wbc)
1564{
1565 return __ext2_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
1566}
1567
1568int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
1569{
1570 struct inode *inode = d_inode(dentry);
1571 int error;
1572
1573 error = inode_change_ok(inode, iattr);
1574 if (error)
1575 return error;
1576
1577 if (is_quota_modification(inode, iattr)) {
1578 error = dquot_initialize(inode);
1579 if (error)
1580 return error;
1581 }
1582 if ((iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)) ||
1583 (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid))) {
1584 error = dquot_transfer(inode, iattr);
1585 if (error)
1586 return error;
1587 }
1588 if (iattr->ia_valid & ATTR_SIZE && iattr->ia_size != inode->i_size) {
1589 error = ext2_setsize(inode, iattr->ia_size);
1590 if (error)
1591 return error;
1592 }
1593 setattr_copy(inode, iattr);
1594 if (iattr->ia_valid & ATTR_MODE)
1595 error = posix_acl_chmod(inode, inode->i_mode);
1596 mark_inode_dirty(inode);
1597
1598 return error;
1599}
1/*
2 * linux/fs/ext2/inode.c
3 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 *
9 * from
10 *
11 * linux/fs/minix/inode.c
12 *
13 * Copyright (C) 1991, 1992 Linus Torvalds
14 *
15 * Goal-directed block allocation by Stephen Tweedie
16 * (sct@dcs.ed.ac.uk), 1993, 1998
17 * Big-endian to little-endian byte-swapping/bitmaps by
18 * David S. Miller (davem@caip.rutgers.edu), 1995
19 * 64-bit file support on 64-bit platforms by Jakub Jelinek
20 * (jj@sunsite.ms.mff.cuni.cz)
21 *
22 * Assorted race fixes, rewrite of ext2_get_block() by Al Viro, 2000
23 */
24
25#include <linux/time.h>
26#include <linux/highuid.h>
27#include <linux/pagemap.h>
28#include <linux/quotaops.h>
29#include <linux/writeback.h>
30#include <linux/buffer_head.h>
31#include <linux/mpage.h>
32#include <linux/fiemap.h>
33#include <linux/namei.h>
34#include "ext2.h"
35#include "acl.h"
36#include "xip.h"
37
38static int __ext2_write_inode(struct inode *inode, int do_sync);
39
40/*
41 * Test whether an inode is a fast symlink.
42 */
43static inline int ext2_inode_is_fast_symlink(struct inode *inode)
44{
45 int ea_blocks = EXT2_I(inode)->i_file_acl ?
46 (inode->i_sb->s_blocksize >> 9) : 0;
47
48 return (S_ISLNK(inode->i_mode) &&
49 inode->i_blocks - ea_blocks == 0);
50}
51
52static void ext2_truncate_blocks(struct inode *inode, loff_t offset);
53
54static void ext2_write_failed(struct address_space *mapping, loff_t to)
55{
56 struct inode *inode = mapping->host;
57
58 if (to > inode->i_size) {
59 truncate_pagecache(inode, to, inode->i_size);
60 ext2_truncate_blocks(inode, inode->i_size);
61 }
62}
63
64/*
65 * Called at the last iput() if i_nlink is zero.
66 */
67void ext2_evict_inode(struct inode * inode)
68{
69 struct ext2_block_alloc_info *rsv;
70 int want_delete = 0;
71
72 if (!inode->i_nlink && !is_bad_inode(inode)) {
73 want_delete = 1;
74 dquot_initialize(inode);
75 } else {
76 dquot_drop(inode);
77 }
78
79 truncate_inode_pages(&inode->i_data, 0);
80
81 if (want_delete) {
82 /* set dtime */
83 EXT2_I(inode)->i_dtime = get_seconds();
84 mark_inode_dirty(inode);
85 __ext2_write_inode(inode, inode_needs_sync(inode));
86 /* truncate to 0 */
87 inode->i_size = 0;
88 if (inode->i_blocks)
89 ext2_truncate_blocks(inode, 0);
90 }
91
92 invalidate_inode_buffers(inode);
93 clear_inode(inode);
94
95 ext2_discard_reservation(inode);
96 rsv = EXT2_I(inode)->i_block_alloc_info;
97 EXT2_I(inode)->i_block_alloc_info = NULL;
98 if (unlikely(rsv))
99 kfree(rsv);
100
101 if (want_delete)
102 ext2_free_inode(inode);
103}
104
105typedef struct {
106 __le32 *p;
107 __le32 key;
108 struct buffer_head *bh;
109} Indirect;
110
111static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
112{
113 p->key = *(p->p = v);
114 p->bh = bh;
115}
116
117static inline int verify_chain(Indirect *from, Indirect *to)
118{
119 while (from <= to && from->key == *from->p)
120 from++;
121 return (from > to);
122}
123
124/**
125 * ext2_block_to_path - parse the block number into array of offsets
126 * @inode: inode in question (we are only interested in its superblock)
127 * @i_block: block number to be parsed
128 * @offsets: array to store the offsets in
129 * @boundary: set this non-zero if the referred-to block is likely to be
130 * followed (on disk) by an indirect block.
131 * To store the locations of file's data ext2 uses a data structure common
132 * for UNIX filesystems - tree of pointers anchored in the inode, with
133 * data blocks at leaves and indirect blocks in intermediate nodes.
134 * This function translates the block number into path in that tree -
135 * return value is the path length and @offsets[n] is the offset of
136 * pointer to (n+1)th node in the nth one. If @block is out of range
137 * (negative or too large) warning is printed and zero returned.
138 *
139 * Note: function doesn't find node addresses, so no IO is needed. All
140 * we need to know is the capacity of indirect blocks (taken from the
141 * inode->i_sb).
142 */
143
144/*
145 * Portability note: the last comparison (check that we fit into triple
146 * indirect block) is spelled differently, because otherwise on an
147 * architecture with 32-bit longs and 8Kb pages we might get into trouble
148 * if our filesystem had 8Kb blocks. We might use long long, but that would
149 * kill us on x86. Oh, well, at least the sign propagation does not matter -
150 * i_block would have to be negative in the very beginning, so we would not
151 * get there at all.
152 */
153
154static int ext2_block_to_path(struct inode *inode,
155 long i_block, int offsets[4], int *boundary)
156{
157 int ptrs = EXT2_ADDR_PER_BLOCK(inode->i_sb);
158 int ptrs_bits = EXT2_ADDR_PER_BLOCK_BITS(inode->i_sb);
159 const long direct_blocks = EXT2_NDIR_BLOCKS,
160 indirect_blocks = ptrs,
161 double_blocks = (1 << (ptrs_bits * 2));
162 int n = 0;
163 int final = 0;
164
165 if (i_block < 0) {
166 ext2_msg(inode->i_sb, KERN_WARNING,
167 "warning: %s: block < 0", __func__);
168 } else if (i_block < direct_blocks) {
169 offsets[n++] = i_block;
170 final = direct_blocks;
171 } else if ( (i_block -= direct_blocks) < indirect_blocks) {
172 offsets[n++] = EXT2_IND_BLOCK;
173 offsets[n++] = i_block;
174 final = ptrs;
175 } else if ((i_block -= indirect_blocks) < double_blocks) {
176 offsets[n++] = EXT2_DIND_BLOCK;
177 offsets[n++] = i_block >> ptrs_bits;
178 offsets[n++] = i_block & (ptrs - 1);
179 final = ptrs;
180 } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
181 offsets[n++] = EXT2_TIND_BLOCK;
182 offsets[n++] = i_block >> (ptrs_bits * 2);
183 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
184 offsets[n++] = i_block & (ptrs - 1);
185 final = ptrs;
186 } else {
187 ext2_msg(inode->i_sb, KERN_WARNING,
188 "warning: %s: block is too big", __func__);
189 }
190 if (boundary)
191 *boundary = final - 1 - (i_block & (ptrs - 1));
192
193 return n;
194}
195
196/**
197 * ext2_get_branch - read the chain of indirect blocks leading to data
198 * @inode: inode in question
199 * @depth: depth of the chain (1 - direct pointer, etc.)
200 * @offsets: offsets of pointers in inode/indirect blocks
201 * @chain: place to store the result
202 * @err: here we store the error value
203 *
204 * Function fills the array of triples <key, p, bh> and returns %NULL
205 * if everything went OK or the pointer to the last filled triple
206 * (incomplete one) otherwise. Upon the return chain[i].key contains
207 * the number of (i+1)-th block in the chain (as it is stored in memory,
208 * i.e. little-endian 32-bit), chain[i].p contains the address of that
209 * number (it points into struct inode for i==0 and into the bh->b_data
210 * for i>0) and chain[i].bh points to the buffer_head of i-th indirect
211 * block for i>0 and NULL for i==0. In other words, it holds the block
212 * numbers of the chain, addresses they were taken from (and where we can
213 * verify that chain did not change) and buffer_heads hosting these
214 * numbers.
215 *
216 * Function stops when it stumbles upon zero pointer (absent block)
217 * (pointer to last triple returned, *@err == 0)
218 * or when it gets an IO error reading an indirect block
219 * (ditto, *@err == -EIO)
220 * or when it notices that chain had been changed while it was reading
221 * (ditto, *@err == -EAGAIN)
222 * or when it reads all @depth-1 indirect blocks successfully and finds
223 * the whole chain, all way to the data (returns %NULL, *err == 0).
224 */
225static Indirect *ext2_get_branch(struct inode *inode,
226 int depth,
227 int *offsets,
228 Indirect chain[4],
229 int *err)
230{
231 struct super_block *sb = inode->i_sb;
232 Indirect *p = chain;
233 struct buffer_head *bh;
234
235 *err = 0;
236 /* i_data is not going away, no lock needed */
237 add_chain (chain, NULL, EXT2_I(inode)->i_data + *offsets);
238 if (!p->key)
239 goto no_block;
240 while (--depth) {
241 bh = sb_bread(sb, le32_to_cpu(p->key));
242 if (!bh)
243 goto failure;
244 read_lock(&EXT2_I(inode)->i_meta_lock);
245 if (!verify_chain(chain, p))
246 goto changed;
247 add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
248 read_unlock(&EXT2_I(inode)->i_meta_lock);
249 if (!p->key)
250 goto no_block;
251 }
252 return NULL;
253
254changed:
255 read_unlock(&EXT2_I(inode)->i_meta_lock);
256 brelse(bh);
257 *err = -EAGAIN;
258 goto no_block;
259failure:
260 *err = -EIO;
261no_block:
262 return p;
263}
264
265/**
266 * ext2_find_near - find a place for allocation with sufficient locality
267 * @inode: owner
268 * @ind: descriptor of indirect block.
269 *
270 * This function returns the preferred place for block allocation.
271 * It is used when heuristic for sequential allocation fails.
272 * Rules are:
273 * + if there is a block to the left of our position - allocate near it.
274 * + if pointer will live in indirect block - allocate near that block.
275 * + if pointer will live in inode - allocate in the same cylinder group.
276 *
277 * In the latter case we colour the starting block by the callers PID to
278 * prevent it from clashing with concurrent allocations for a different inode
279 * in the same block group. The PID is used here so that functionally related
280 * files will be close-by on-disk.
281 *
282 * Caller must make sure that @ind is valid and will stay that way.
283 */
284
285static ext2_fsblk_t ext2_find_near(struct inode *inode, Indirect *ind)
286{
287 struct ext2_inode_info *ei = EXT2_I(inode);
288 __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
289 __le32 *p;
290 ext2_fsblk_t bg_start;
291 ext2_fsblk_t colour;
292
293 /* Try to find previous block */
294 for (p = ind->p - 1; p >= start; p--)
295 if (*p)
296 return le32_to_cpu(*p);
297
298 /* No such thing, so let's try location of indirect block */
299 if (ind->bh)
300 return ind->bh->b_blocknr;
301
302 /*
303 * It is going to be referred from inode itself? OK, just put it into
304 * the same cylinder group then.
305 */
306 bg_start = ext2_group_first_block_no(inode->i_sb, ei->i_block_group);
307 colour = (current->pid % 16) *
308 (EXT2_BLOCKS_PER_GROUP(inode->i_sb) / 16);
309 return bg_start + colour;
310}
311
312/**
313 * ext2_find_goal - find a preferred place for allocation.
314 * @inode: owner
315 * @block: block we want
316 * @partial: pointer to the last triple within a chain
317 *
318 * Returns preferred place for a block (the goal).
319 */
320
321static inline ext2_fsblk_t ext2_find_goal(struct inode *inode, long block,
322 Indirect *partial)
323{
324 struct ext2_block_alloc_info *block_i;
325
326 block_i = EXT2_I(inode)->i_block_alloc_info;
327
328 /*
329 * try the heuristic for sequential allocation,
330 * failing that at least try to get decent locality.
331 */
332 if (block_i && (block == block_i->last_alloc_logical_block + 1)
333 && (block_i->last_alloc_physical_block != 0)) {
334 return block_i->last_alloc_physical_block + 1;
335 }
336
337 return ext2_find_near(inode, partial);
338}
339
340/**
341 * ext2_blks_to_allocate: Look up the block map and count the number
342 * of direct blocks need to be allocated for the given branch.
343 *
344 * @branch: chain of indirect blocks
345 * @k: number of blocks need for indirect blocks
346 * @blks: number of data blocks to be mapped.
347 * @blocks_to_boundary: the offset in the indirect block
348 *
349 * return the total number of blocks to be allocate, including the
350 * direct and indirect blocks.
351 */
352static int
353ext2_blks_to_allocate(Indirect * branch, int k, unsigned long blks,
354 int blocks_to_boundary)
355{
356 unsigned long count = 0;
357
358 /*
359 * Simple case, [t,d]Indirect block(s) has not allocated yet
360 * then it's clear blocks on that path have not allocated
361 */
362 if (k > 0) {
363 /* right now don't hanel cross boundary allocation */
364 if (blks < blocks_to_boundary + 1)
365 count += blks;
366 else
367 count += blocks_to_boundary + 1;
368 return count;
369 }
370
371 count++;
372 while (count < blks && count <= blocks_to_boundary
373 && le32_to_cpu(*(branch[0].p + count)) == 0) {
374 count++;
375 }
376 return count;
377}
378
379/**
380 * ext2_alloc_blocks: multiple allocate blocks needed for a branch
381 * @indirect_blks: the number of blocks need to allocate for indirect
382 * blocks
383 *
384 * @new_blocks: on return it will store the new block numbers for
385 * the indirect blocks(if needed) and the first direct block,
386 * @blks: on return it will store the total number of allocated
387 * direct blocks
388 */
389static int ext2_alloc_blocks(struct inode *inode,
390 ext2_fsblk_t goal, int indirect_blks, int blks,
391 ext2_fsblk_t new_blocks[4], int *err)
392{
393 int target, i;
394 unsigned long count = 0;
395 int index = 0;
396 ext2_fsblk_t current_block = 0;
397 int ret = 0;
398
399 /*
400 * Here we try to allocate the requested multiple blocks at once,
401 * on a best-effort basis.
402 * To build a branch, we should allocate blocks for
403 * the indirect blocks(if not allocated yet), and at least
404 * the first direct block of this branch. That's the
405 * minimum number of blocks need to allocate(required)
406 */
407 target = blks + indirect_blks;
408
409 while (1) {
410 count = target;
411 /* allocating blocks for indirect blocks and direct blocks */
412 current_block = ext2_new_blocks(inode,goal,&count,err);
413 if (*err)
414 goto failed_out;
415
416 target -= count;
417 /* allocate blocks for indirect blocks */
418 while (index < indirect_blks && count) {
419 new_blocks[index++] = current_block++;
420 count--;
421 }
422
423 if (count > 0)
424 break;
425 }
426
427 /* save the new block number for the first direct block */
428 new_blocks[index] = current_block;
429
430 /* total number of blocks allocated for direct blocks */
431 ret = count;
432 *err = 0;
433 return ret;
434failed_out:
435 for (i = 0; i <index; i++)
436 ext2_free_blocks(inode, new_blocks[i], 1);
437 if (index)
438 mark_inode_dirty(inode);
439 return ret;
440}
441
442/**
443 * ext2_alloc_branch - allocate and set up a chain of blocks.
444 * @inode: owner
445 * @num: depth of the chain (number of blocks to allocate)
446 * @offsets: offsets (in the blocks) to store the pointers to next.
447 * @branch: place to store the chain in.
448 *
449 * This function allocates @num blocks, zeroes out all but the last one,
450 * links them into chain and (if we are synchronous) writes them to disk.
451 * In other words, it prepares a branch that can be spliced onto the
452 * inode. It stores the information about that chain in the branch[], in
453 * the same format as ext2_get_branch() would do. We are calling it after
454 * we had read the existing part of chain and partial points to the last
455 * triple of that (one with zero ->key). Upon the exit we have the same
456 * picture as after the successful ext2_get_block(), except that in one
457 * place chain is disconnected - *branch->p is still zero (we did not
458 * set the last link), but branch->key contains the number that should
459 * be placed into *branch->p to fill that gap.
460 *
461 * If allocation fails we free all blocks we've allocated (and forget
462 * their buffer_heads) and return the error value the from failed
463 * ext2_alloc_block() (normally -ENOSPC). Otherwise we set the chain
464 * as described above and return 0.
465 */
466
467static int ext2_alloc_branch(struct inode *inode,
468 int indirect_blks, int *blks, ext2_fsblk_t goal,
469 int *offsets, Indirect *branch)
470{
471 int blocksize = inode->i_sb->s_blocksize;
472 int i, n = 0;
473 int err = 0;
474 struct buffer_head *bh;
475 int num;
476 ext2_fsblk_t new_blocks[4];
477 ext2_fsblk_t current_block;
478
479 num = ext2_alloc_blocks(inode, goal, indirect_blks,
480 *blks, new_blocks, &err);
481 if (err)
482 return err;
483
484 branch[0].key = cpu_to_le32(new_blocks[0]);
485 /*
486 * metadata blocks and data blocks are allocated.
487 */
488 for (n = 1; n <= indirect_blks; n++) {
489 /*
490 * Get buffer_head for parent block, zero it out
491 * and set the pointer to new one, then send
492 * parent to disk.
493 */
494 bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
495 branch[n].bh = bh;
496 lock_buffer(bh);
497 memset(bh->b_data, 0, blocksize);
498 branch[n].p = (__le32 *) bh->b_data + offsets[n];
499 branch[n].key = cpu_to_le32(new_blocks[n]);
500 *branch[n].p = branch[n].key;
501 if ( n == indirect_blks) {
502 current_block = new_blocks[n];
503 /*
504 * End of chain, update the last new metablock of
505 * the chain to point to the new allocated
506 * data blocks numbers
507 */
508 for (i=1; i < num; i++)
509 *(branch[n].p + i) = cpu_to_le32(++current_block);
510 }
511 set_buffer_uptodate(bh);
512 unlock_buffer(bh);
513 mark_buffer_dirty_inode(bh, inode);
514 /* We used to sync bh here if IS_SYNC(inode).
515 * But we now rely upon generic_write_sync()
516 * and b_inode_buffers. But not for directories.
517 */
518 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
519 sync_dirty_buffer(bh);
520 }
521 *blks = num;
522 return err;
523}
524
525/**
526 * ext2_splice_branch - splice the allocated branch onto inode.
527 * @inode: owner
528 * @block: (logical) number of block we are adding
529 * @where: location of missing link
530 * @num: number of indirect blocks we are adding
531 * @blks: number of direct blocks we are adding
532 *
533 * This function fills the missing link and does all housekeeping needed in
534 * inode (->i_blocks, etc.). In case of success we end up with the full
535 * chain to new block and return 0.
536 */
537static void ext2_splice_branch(struct inode *inode,
538 long block, Indirect *where, int num, int blks)
539{
540 int i;
541 struct ext2_block_alloc_info *block_i;
542 ext2_fsblk_t current_block;
543
544 block_i = EXT2_I(inode)->i_block_alloc_info;
545
546 /* XXX LOCKING probably should have i_meta_lock ?*/
547 /* That's it */
548
549 *where->p = where->key;
550
551 /*
552 * Update the host buffer_head or inode to point to more just allocated
553 * direct blocks blocks
554 */
555 if (num == 0 && blks > 1) {
556 current_block = le32_to_cpu(where->key) + 1;
557 for (i = 1; i < blks; i++)
558 *(where->p + i ) = cpu_to_le32(current_block++);
559 }
560
561 /*
562 * update the most recently allocated logical & physical block
563 * in i_block_alloc_info, to assist find the proper goal block for next
564 * allocation
565 */
566 if (block_i) {
567 block_i->last_alloc_logical_block = block + blks - 1;
568 block_i->last_alloc_physical_block =
569 le32_to_cpu(where[num].key) + blks - 1;
570 }
571
572 /* We are done with atomic stuff, now do the rest of housekeeping */
573
574 /* had we spliced it onto indirect block? */
575 if (where->bh)
576 mark_buffer_dirty_inode(where->bh, inode);
577
578 inode->i_ctime = CURRENT_TIME_SEC;
579 mark_inode_dirty(inode);
580}
581
582/*
583 * Allocation strategy is simple: if we have to allocate something, we will
584 * have to go the whole way to leaf. So let's do it before attaching anything
585 * to tree, set linkage between the newborn blocks, write them if sync is
586 * required, recheck the path, free and repeat if check fails, otherwise
587 * set the last missing link (that will protect us from any truncate-generated
588 * removals - all blocks on the path are immune now) and possibly force the
589 * write on the parent block.
590 * That has a nice additional property: no special recovery from the failed
591 * allocations is needed - we simply release blocks and do not touch anything
592 * reachable from inode.
593 *
594 * `handle' can be NULL if create == 0.
595 *
596 * return > 0, # of blocks mapped or allocated.
597 * return = 0, if plain lookup failed.
598 * return < 0, error case.
599 */
600static int ext2_get_blocks(struct inode *inode,
601 sector_t iblock, unsigned long maxblocks,
602 struct buffer_head *bh_result,
603 int create)
604{
605 int err = -EIO;
606 int offsets[4];
607 Indirect chain[4];
608 Indirect *partial;
609 ext2_fsblk_t goal;
610 int indirect_blks;
611 int blocks_to_boundary = 0;
612 int depth;
613 struct ext2_inode_info *ei = EXT2_I(inode);
614 int count = 0;
615 ext2_fsblk_t first_block = 0;
616
617 depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
618
619 if (depth == 0)
620 return (err);
621
622 partial = ext2_get_branch(inode, depth, offsets, chain, &err);
623 /* Simplest case - block found, no allocation needed */
624 if (!partial) {
625 first_block = le32_to_cpu(chain[depth - 1].key);
626 clear_buffer_new(bh_result); /* What's this do? */
627 count++;
628 /*map more blocks*/
629 while (count < maxblocks && count <= blocks_to_boundary) {
630 ext2_fsblk_t blk;
631
632 if (!verify_chain(chain, chain + depth - 1)) {
633 /*
634 * Indirect block might be removed by
635 * truncate while we were reading it.
636 * Handling of that case: forget what we've
637 * got now, go to reread.
638 */
639 err = -EAGAIN;
640 count = 0;
641 break;
642 }
643 blk = le32_to_cpu(*(chain[depth-1].p + count));
644 if (blk == first_block + count)
645 count++;
646 else
647 break;
648 }
649 if (err != -EAGAIN)
650 goto got_it;
651 }
652
653 /* Next simple case - plain lookup or failed read of indirect block */
654 if (!create || err == -EIO)
655 goto cleanup;
656
657 mutex_lock(&ei->truncate_mutex);
658 /*
659 * If the indirect block is missing while we are reading
660 * the chain(ext2_get_branch() returns -EAGAIN err), or
661 * if the chain has been changed after we grab the semaphore,
662 * (either because another process truncated this branch, or
663 * another get_block allocated this branch) re-grab the chain to see if
664 * the request block has been allocated or not.
665 *
666 * Since we already block the truncate/other get_block
667 * at this point, we will have the current copy of the chain when we
668 * splice the branch into the tree.
669 */
670 if (err == -EAGAIN || !verify_chain(chain, partial)) {
671 while (partial > chain) {
672 brelse(partial->bh);
673 partial--;
674 }
675 partial = ext2_get_branch(inode, depth, offsets, chain, &err);
676 if (!partial) {
677 count++;
678 mutex_unlock(&ei->truncate_mutex);
679 if (err)
680 goto cleanup;
681 clear_buffer_new(bh_result);
682 goto got_it;
683 }
684 }
685
686 /*
687 * Okay, we need to do block allocation. Lazily initialize the block
688 * allocation info here if necessary
689 */
690 if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
691 ext2_init_block_alloc_info(inode);
692
693 goal = ext2_find_goal(inode, iblock, partial);
694
695 /* the number of blocks need to allocate for [d,t]indirect blocks */
696 indirect_blks = (chain + depth) - partial - 1;
697 /*
698 * Next look up the indirect map to count the totoal number of
699 * direct blocks to allocate for this branch.
700 */
701 count = ext2_blks_to_allocate(partial, indirect_blks,
702 maxblocks, blocks_to_boundary);
703 /*
704 * XXX ???? Block out ext2_truncate while we alter the tree
705 */
706 err = ext2_alloc_branch(inode, indirect_blks, &count, goal,
707 offsets + (partial - chain), partial);
708
709 if (err) {
710 mutex_unlock(&ei->truncate_mutex);
711 goto cleanup;
712 }
713
714 if (ext2_use_xip(inode->i_sb)) {
715 /*
716 * we need to clear the block
717 */
718 err = ext2_clear_xip_target (inode,
719 le32_to_cpu(chain[depth-1].key));
720 if (err) {
721 mutex_unlock(&ei->truncate_mutex);
722 goto cleanup;
723 }
724 }
725
726 ext2_splice_branch(inode, iblock, partial, indirect_blks, count);
727 mutex_unlock(&ei->truncate_mutex);
728 set_buffer_new(bh_result);
729got_it:
730 map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
731 if (count > blocks_to_boundary)
732 set_buffer_boundary(bh_result);
733 err = count;
734 /* Clean up and exit */
735 partial = chain + depth - 1; /* the whole chain */
736cleanup:
737 while (partial > chain) {
738 brelse(partial->bh);
739 partial--;
740 }
741 return err;
742}
743
744int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
745{
746 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
747 int ret = ext2_get_blocks(inode, iblock, max_blocks,
748 bh_result, create);
749 if (ret > 0) {
750 bh_result->b_size = (ret << inode->i_blkbits);
751 ret = 0;
752 }
753 return ret;
754
755}
756
757int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
758 u64 start, u64 len)
759{
760 return generic_block_fiemap(inode, fieinfo, start, len,
761 ext2_get_block);
762}
763
764static int ext2_writepage(struct page *page, struct writeback_control *wbc)
765{
766 return block_write_full_page(page, ext2_get_block, wbc);
767}
768
769static int ext2_readpage(struct file *file, struct page *page)
770{
771 return mpage_readpage(page, ext2_get_block);
772}
773
774static int
775ext2_readpages(struct file *file, struct address_space *mapping,
776 struct list_head *pages, unsigned nr_pages)
777{
778 return mpage_readpages(mapping, pages, nr_pages, ext2_get_block);
779}
780
781static int
782ext2_write_begin(struct file *file, struct address_space *mapping,
783 loff_t pos, unsigned len, unsigned flags,
784 struct page **pagep, void **fsdata)
785{
786 int ret;
787
788 ret = block_write_begin(mapping, pos, len, flags, pagep,
789 ext2_get_block);
790 if (ret < 0)
791 ext2_write_failed(mapping, pos + len);
792 return ret;
793}
794
795static int ext2_write_end(struct file *file, struct address_space *mapping,
796 loff_t pos, unsigned len, unsigned copied,
797 struct page *page, void *fsdata)
798{
799 int ret;
800
801 ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
802 if (ret < len)
803 ext2_write_failed(mapping, pos + len);
804 return ret;
805}
806
807static int
808ext2_nobh_write_begin(struct file *file, struct address_space *mapping,
809 loff_t pos, unsigned len, unsigned flags,
810 struct page **pagep, void **fsdata)
811{
812 int ret;
813
814 ret = nobh_write_begin(mapping, pos, len, flags, pagep, fsdata,
815 ext2_get_block);
816 if (ret < 0)
817 ext2_write_failed(mapping, pos + len);
818 return ret;
819}
820
821static int ext2_nobh_writepage(struct page *page,
822 struct writeback_control *wbc)
823{
824 return nobh_writepage(page, ext2_get_block, wbc);
825}
826
827static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
828{
829 return generic_block_bmap(mapping,block,ext2_get_block);
830}
831
832static ssize_t
833ext2_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
834 loff_t offset, unsigned long nr_segs)
835{
836 struct file *file = iocb->ki_filp;
837 struct address_space *mapping = file->f_mapping;
838 struct inode *inode = mapping->host;
839 ssize_t ret;
840
841 ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
842 ext2_get_block);
843 if (ret < 0 && (rw & WRITE))
844 ext2_write_failed(mapping, offset + iov_length(iov, nr_segs));
845 return ret;
846}
847
848static int
849ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
850{
851 return mpage_writepages(mapping, wbc, ext2_get_block);
852}
853
854const struct address_space_operations ext2_aops = {
855 .readpage = ext2_readpage,
856 .readpages = ext2_readpages,
857 .writepage = ext2_writepage,
858 .write_begin = ext2_write_begin,
859 .write_end = ext2_write_end,
860 .bmap = ext2_bmap,
861 .direct_IO = ext2_direct_IO,
862 .writepages = ext2_writepages,
863 .migratepage = buffer_migrate_page,
864 .is_partially_uptodate = block_is_partially_uptodate,
865 .error_remove_page = generic_error_remove_page,
866};
867
868const struct address_space_operations ext2_aops_xip = {
869 .bmap = ext2_bmap,
870 .get_xip_mem = ext2_get_xip_mem,
871};
872
873const struct address_space_operations ext2_nobh_aops = {
874 .readpage = ext2_readpage,
875 .readpages = ext2_readpages,
876 .writepage = ext2_nobh_writepage,
877 .write_begin = ext2_nobh_write_begin,
878 .write_end = nobh_write_end,
879 .bmap = ext2_bmap,
880 .direct_IO = ext2_direct_IO,
881 .writepages = ext2_writepages,
882 .migratepage = buffer_migrate_page,
883 .error_remove_page = generic_error_remove_page,
884};
885
886/*
887 * Probably it should be a library function... search for first non-zero word
888 * or memcmp with zero_page, whatever is better for particular architecture.
889 * Linus?
890 */
891static inline int all_zeroes(__le32 *p, __le32 *q)
892{
893 while (p < q)
894 if (*p++)
895 return 0;
896 return 1;
897}
898
899/**
900 * ext2_find_shared - find the indirect blocks for partial truncation.
901 * @inode: inode in question
902 * @depth: depth of the affected branch
903 * @offsets: offsets of pointers in that branch (see ext2_block_to_path)
904 * @chain: place to store the pointers to partial indirect blocks
905 * @top: place to the (detached) top of branch
906 *
907 * This is a helper function used by ext2_truncate().
908 *
909 * When we do truncate() we may have to clean the ends of several indirect
910 * blocks but leave the blocks themselves alive. Block is partially
911 * truncated if some data below the new i_size is referred from it (and
912 * it is on the path to the first completely truncated data block, indeed).
913 * We have to free the top of that path along with everything to the right
914 * of the path. Since no allocation past the truncation point is possible
915 * until ext2_truncate() finishes, we may safely do the latter, but top
916 * of branch may require special attention - pageout below the truncation
917 * point might try to populate it.
918 *
919 * We atomically detach the top of branch from the tree, store the block
920 * number of its root in *@top, pointers to buffer_heads of partially
921 * truncated blocks - in @chain[].bh and pointers to their last elements
922 * that should not be removed - in @chain[].p. Return value is the pointer
923 * to last filled element of @chain.
924 *
925 * The work left to caller to do the actual freeing of subtrees:
926 * a) free the subtree starting from *@top
927 * b) free the subtrees whose roots are stored in
928 * (@chain[i].p+1 .. end of @chain[i].bh->b_data)
929 * c) free the subtrees growing from the inode past the @chain[0].p
930 * (no partially truncated stuff there).
931 */
932
933static Indirect *ext2_find_shared(struct inode *inode,
934 int depth,
935 int offsets[4],
936 Indirect chain[4],
937 __le32 *top)
938{
939 Indirect *partial, *p;
940 int k, err;
941
942 *top = 0;
943 for (k = depth; k > 1 && !offsets[k-1]; k--)
944 ;
945 partial = ext2_get_branch(inode, k, offsets, chain, &err);
946 if (!partial)
947 partial = chain + k-1;
948 /*
949 * If the branch acquired continuation since we've looked at it -
950 * fine, it should all survive and (new) top doesn't belong to us.
951 */
952 write_lock(&EXT2_I(inode)->i_meta_lock);
953 if (!partial->key && *partial->p) {
954 write_unlock(&EXT2_I(inode)->i_meta_lock);
955 goto no_top;
956 }
957 for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
958 ;
959 /*
960 * OK, we've found the last block that must survive. The rest of our
961 * branch should be detached before unlocking. However, if that rest
962 * of branch is all ours and does not grow immediately from the inode
963 * it's easier to cheat and just decrement partial->p.
964 */
965 if (p == chain + k - 1 && p > chain) {
966 p->p--;
967 } else {
968 *top = *p->p;
969 *p->p = 0;
970 }
971 write_unlock(&EXT2_I(inode)->i_meta_lock);
972
973 while(partial > p)
974 {
975 brelse(partial->bh);
976 partial--;
977 }
978no_top:
979 return partial;
980}
981
982/**
983 * ext2_free_data - free a list of data blocks
984 * @inode: inode we are dealing with
985 * @p: array of block numbers
986 * @q: points immediately past the end of array
987 *
988 * We are freeing all blocks referred from that array (numbers are
989 * stored as little-endian 32-bit) and updating @inode->i_blocks
990 * appropriately.
991 */
992static inline void ext2_free_data(struct inode *inode, __le32 *p, __le32 *q)
993{
994 unsigned long block_to_free = 0, count = 0;
995 unsigned long nr;
996
997 for ( ; p < q ; p++) {
998 nr = le32_to_cpu(*p);
999 if (nr) {
1000 *p = 0;
1001 /* accumulate blocks to free if they're contiguous */
1002 if (count == 0)
1003 goto free_this;
1004 else if (block_to_free == nr - count)
1005 count++;
1006 else {
1007 ext2_free_blocks (inode, block_to_free, count);
1008 mark_inode_dirty(inode);
1009 free_this:
1010 block_to_free = nr;
1011 count = 1;
1012 }
1013 }
1014 }
1015 if (count > 0) {
1016 ext2_free_blocks (inode, block_to_free, count);
1017 mark_inode_dirty(inode);
1018 }
1019}
1020
1021/**
1022 * ext2_free_branches - free an array of branches
1023 * @inode: inode we are dealing with
1024 * @p: array of block numbers
1025 * @q: pointer immediately past the end of array
1026 * @depth: depth of the branches to free
1027 *
1028 * We are freeing all blocks referred from these branches (numbers are
1029 * stored as little-endian 32-bit) and updating @inode->i_blocks
1030 * appropriately.
1031 */
1032static void ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int depth)
1033{
1034 struct buffer_head * bh;
1035 unsigned long nr;
1036
1037 if (depth--) {
1038 int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1039 for ( ; p < q ; p++) {
1040 nr = le32_to_cpu(*p);
1041 if (!nr)
1042 continue;
1043 *p = 0;
1044 bh = sb_bread(inode->i_sb, nr);
1045 /*
1046 * A read failure? Report error and clear slot
1047 * (should be rare).
1048 */
1049 if (!bh) {
1050 ext2_error(inode->i_sb, "ext2_free_branches",
1051 "Read failure, inode=%ld, block=%ld",
1052 inode->i_ino, nr);
1053 continue;
1054 }
1055 ext2_free_branches(inode,
1056 (__le32*)bh->b_data,
1057 (__le32*)bh->b_data + addr_per_block,
1058 depth);
1059 bforget(bh);
1060 ext2_free_blocks(inode, nr, 1);
1061 mark_inode_dirty(inode);
1062 }
1063 } else
1064 ext2_free_data(inode, p, q);
1065}
1066
1067static void __ext2_truncate_blocks(struct inode *inode, loff_t offset)
1068{
1069 __le32 *i_data = EXT2_I(inode)->i_data;
1070 struct ext2_inode_info *ei = EXT2_I(inode);
1071 int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1072 int offsets[4];
1073 Indirect chain[4];
1074 Indirect *partial;
1075 __le32 nr = 0;
1076 int n;
1077 long iblock;
1078 unsigned blocksize;
1079 blocksize = inode->i_sb->s_blocksize;
1080 iblock = (offset + blocksize-1) >> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
1081
1082 n = ext2_block_to_path(inode, iblock, offsets, NULL);
1083 if (n == 0)
1084 return;
1085
1086 /*
1087 * From here we block out all ext2_get_block() callers who want to
1088 * modify the block allocation tree.
1089 */
1090 mutex_lock(&ei->truncate_mutex);
1091
1092 if (n == 1) {
1093 ext2_free_data(inode, i_data+offsets[0],
1094 i_data + EXT2_NDIR_BLOCKS);
1095 goto do_indirects;
1096 }
1097
1098 partial = ext2_find_shared(inode, n, offsets, chain, &nr);
1099 /* Kill the top of shared branch (already detached) */
1100 if (nr) {
1101 if (partial == chain)
1102 mark_inode_dirty(inode);
1103 else
1104 mark_buffer_dirty_inode(partial->bh, inode);
1105 ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
1106 }
1107 /* Clear the ends of indirect blocks on the shared branch */
1108 while (partial > chain) {
1109 ext2_free_branches(inode,
1110 partial->p + 1,
1111 (__le32*)partial->bh->b_data+addr_per_block,
1112 (chain+n-1) - partial);
1113 mark_buffer_dirty_inode(partial->bh, inode);
1114 brelse (partial->bh);
1115 partial--;
1116 }
1117do_indirects:
1118 /* Kill the remaining (whole) subtrees */
1119 switch (offsets[0]) {
1120 default:
1121 nr = i_data[EXT2_IND_BLOCK];
1122 if (nr) {
1123 i_data[EXT2_IND_BLOCK] = 0;
1124 mark_inode_dirty(inode);
1125 ext2_free_branches(inode, &nr, &nr+1, 1);
1126 }
1127 case EXT2_IND_BLOCK:
1128 nr = i_data[EXT2_DIND_BLOCK];
1129 if (nr) {
1130 i_data[EXT2_DIND_BLOCK] = 0;
1131 mark_inode_dirty(inode);
1132 ext2_free_branches(inode, &nr, &nr+1, 2);
1133 }
1134 case EXT2_DIND_BLOCK:
1135 nr = i_data[EXT2_TIND_BLOCK];
1136 if (nr) {
1137 i_data[EXT2_TIND_BLOCK] = 0;
1138 mark_inode_dirty(inode);
1139 ext2_free_branches(inode, &nr, &nr+1, 3);
1140 }
1141 case EXT2_TIND_BLOCK:
1142 ;
1143 }
1144
1145 ext2_discard_reservation(inode);
1146
1147 mutex_unlock(&ei->truncate_mutex);
1148}
1149
1150static void ext2_truncate_blocks(struct inode *inode, loff_t offset)
1151{
1152 /*
1153 * XXX: it seems like a bug here that we don't allow
1154 * IS_APPEND inode to have blocks-past-i_size trimmed off.
1155 * review and fix this.
1156 *
1157 * Also would be nice to be able to handle IO errors and such,
1158 * but that's probably too much to ask.
1159 */
1160 if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1161 S_ISLNK(inode->i_mode)))
1162 return;
1163 if (ext2_inode_is_fast_symlink(inode))
1164 return;
1165 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1166 return;
1167 __ext2_truncate_blocks(inode, offset);
1168}
1169
1170static int ext2_setsize(struct inode *inode, loff_t newsize)
1171{
1172 int error;
1173
1174 if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1175 S_ISLNK(inode->i_mode)))
1176 return -EINVAL;
1177 if (ext2_inode_is_fast_symlink(inode))
1178 return -EINVAL;
1179 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1180 return -EPERM;
1181
1182 inode_dio_wait(inode);
1183
1184 if (mapping_is_xip(inode->i_mapping))
1185 error = xip_truncate_page(inode->i_mapping, newsize);
1186 else if (test_opt(inode->i_sb, NOBH))
1187 error = nobh_truncate_page(inode->i_mapping,
1188 newsize, ext2_get_block);
1189 else
1190 error = block_truncate_page(inode->i_mapping,
1191 newsize, ext2_get_block);
1192 if (error)
1193 return error;
1194
1195 truncate_setsize(inode, newsize);
1196 __ext2_truncate_blocks(inode, newsize);
1197
1198 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
1199 if (inode_needs_sync(inode)) {
1200 sync_mapping_buffers(inode->i_mapping);
1201 sync_inode_metadata(inode, 1);
1202 } else {
1203 mark_inode_dirty(inode);
1204 }
1205
1206 return 0;
1207}
1208
1209static struct ext2_inode *ext2_get_inode(struct super_block *sb, ino_t ino,
1210 struct buffer_head **p)
1211{
1212 struct buffer_head * bh;
1213 unsigned long block_group;
1214 unsigned long block;
1215 unsigned long offset;
1216 struct ext2_group_desc * gdp;
1217
1218 *p = NULL;
1219 if ((ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) ||
1220 ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
1221 goto Einval;
1222
1223 block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
1224 gdp = ext2_get_group_desc(sb, block_group, NULL);
1225 if (!gdp)
1226 goto Egdp;
1227 /*
1228 * Figure out the offset within the block group inode table
1229 */
1230 offset = ((ino - 1) % EXT2_INODES_PER_GROUP(sb)) * EXT2_INODE_SIZE(sb);
1231 block = le32_to_cpu(gdp->bg_inode_table) +
1232 (offset >> EXT2_BLOCK_SIZE_BITS(sb));
1233 if (!(bh = sb_bread(sb, block)))
1234 goto Eio;
1235
1236 *p = bh;
1237 offset &= (EXT2_BLOCK_SIZE(sb) - 1);
1238 return (struct ext2_inode *) (bh->b_data + offset);
1239
1240Einval:
1241 ext2_error(sb, "ext2_get_inode", "bad inode number: %lu",
1242 (unsigned long) ino);
1243 return ERR_PTR(-EINVAL);
1244Eio:
1245 ext2_error(sb, "ext2_get_inode",
1246 "unable to read inode block - inode=%lu, block=%lu",
1247 (unsigned long) ino, block);
1248Egdp:
1249 return ERR_PTR(-EIO);
1250}
1251
1252void ext2_set_inode_flags(struct inode *inode)
1253{
1254 unsigned int flags = EXT2_I(inode)->i_flags;
1255
1256 inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
1257 if (flags & EXT2_SYNC_FL)
1258 inode->i_flags |= S_SYNC;
1259 if (flags & EXT2_APPEND_FL)
1260 inode->i_flags |= S_APPEND;
1261 if (flags & EXT2_IMMUTABLE_FL)
1262 inode->i_flags |= S_IMMUTABLE;
1263 if (flags & EXT2_NOATIME_FL)
1264 inode->i_flags |= S_NOATIME;
1265 if (flags & EXT2_DIRSYNC_FL)
1266 inode->i_flags |= S_DIRSYNC;
1267}
1268
1269/* Propagate flags from i_flags to EXT2_I(inode)->i_flags */
1270void ext2_get_inode_flags(struct ext2_inode_info *ei)
1271{
1272 unsigned int flags = ei->vfs_inode.i_flags;
1273
1274 ei->i_flags &= ~(EXT2_SYNC_FL|EXT2_APPEND_FL|
1275 EXT2_IMMUTABLE_FL|EXT2_NOATIME_FL|EXT2_DIRSYNC_FL);
1276 if (flags & S_SYNC)
1277 ei->i_flags |= EXT2_SYNC_FL;
1278 if (flags & S_APPEND)
1279 ei->i_flags |= EXT2_APPEND_FL;
1280 if (flags & S_IMMUTABLE)
1281 ei->i_flags |= EXT2_IMMUTABLE_FL;
1282 if (flags & S_NOATIME)
1283 ei->i_flags |= EXT2_NOATIME_FL;
1284 if (flags & S_DIRSYNC)
1285 ei->i_flags |= EXT2_DIRSYNC_FL;
1286}
1287
1288struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
1289{
1290 struct ext2_inode_info *ei;
1291 struct buffer_head * bh;
1292 struct ext2_inode *raw_inode;
1293 struct inode *inode;
1294 long ret = -EIO;
1295 int n;
1296 uid_t i_uid;
1297 gid_t i_gid;
1298
1299 inode = iget_locked(sb, ino);
1300 if (!inode)
1301 return ERR_PTR(-ENOMEM);
1302 if (!(inode->i_state & I_NEW))
1303 return inode;
1304
1305 ei = EXT2_I(inode);
1306 ei->i_block_alloc_info = NULL;
1307
1308 raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
1309 if (IS_ERR(raw_inode)) {
1310 ret = PTR_ERR(raw_inode);
1311 goto bad_inode;
1312 }
1313
1314 inode->i_mode = le16_to_cpu(raw_inode->i_mode);
1315 i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
1316 i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
1317 if (!(test_opt (inode->i_sb, NO_UID32))) {
1318 i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
1319 i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
1320 }
1321 i_uid_write(inode, i_uid);
1322 i_gid_write(inode, i_gid);
1323 set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
1324 inode->i_size = le32_to_cpu(raw_inode->i_size);
1325 inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
1326 inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
1327 inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
1328 inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1329 ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
1330 /* We now have enough fields to check if the inode was active or not.
1331 * This is needed because nfsd might try to access dead inodes
1332 * the test is that same one that e2fsck uses
1333 * NeilBrown 1999oct15
1334 */
1335 if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
1336 /* this inode is deleted */
1337 brelse (bh);
1338 ret = -ESTALE;
1339 goto bad_inode;
1340 }
1341 inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
1342 ei->i_flags = le32_to_cpu(raw_inode->i_flags);
1343 ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
1344 ei->i_frag_no = raw_inode->i_frag;
1345 ei->i_frag_size = raw_inode->i_fsize;
1346 ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
1347 ei->i_dir_acl = 0;
1348 if (S_ISREG(inode->i_mode))
1349 inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
1350 else
1351 ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
1352 ei->i_dtime = 0;
1353 inode->i_generation = le32_to_cpu(raw_inode->i_generation);
1354 ei->i_state = 0;
1355 ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
1356 ei->i_dir_start_lookup = 0;
1357
1358 /*
1359 * NOTE! The in-memory inode i_data array is in little-endian order
1360 * even on big-endian machines: we do NOT byteswap the block numbers!
1361 */
1362 for (n = 0; n < EXT2_N_BLOCKS; n++)
1363 ei->i_data[n] = raw_inode->i_block[n];
1364
1365 if (S_ISREG(inode->i_mode)) {
1366 inode->i_op = &ext2_file_inode_operations;
1367 if (ext2_use_xip(inode->i_sb)) {
1368 inode->i_mapping->a_ops = &ext2_aops_xip;
1369 inode->i_fop = &ext2_xip_file_operations;
1370 } else if (test_opt(inode->i_sb, NOBH)) {
1371 inode->i_mapping->a_ops = &ext2_nobh_aops;
1372 inode->i_fop = &ext2_file_operations;
1373 } else {
1374 inode->i_mapping->a_ops = &ext2_aops;
1375 inode->i_fop = &ext2_file_operations;
1376 }
1377 } else if (S_ISDIR(inode->i_mode)) {
1378 inode->i_op = &ext2_dir_inode_operations;
1379 inode->i_fop = &ext2_dir_operations;
1380 if (test_opt(inode->i_sb, NOBH))
1381 inode->i_mapping->a_ops = &ext2_nobh_aops;
1382 else
1383 inode->i_mapping->a_ops = &ext2_aops;
1384 } else if (S_ISLNK(inode->i_mode)) {
1385 if (ext2_inode_is_fast_symlink(inode)) {
1386 inode->i_op = &ext2_fast_symlink_inode_operations;
1387 nd_terminate_link(ei->i_data, inode->i_size,
1388 sizeof(ei->i_data) - 1);
1389 } else {
1390 inode->i_op = &ext2_symlink_inode_operations;
1391 if (test_opt(inode->i_sb, NOBH))
1392 inode->i_mapping->a_ops = &ext2_nobh_aops;
1393 else
1394 inode->i_mapping->a_ops = &ext2_aops;
1395 }
1396 } else {
1397 inode->i_op = &ext2_special_inode_operations;
1398 if (raw_inode->i_block[0])
1399 init_special_inode(inode, inode->i_mode,
1400 old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
1401 else
1402 init_special_inode(inode, inode->i_mode,
1403 new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
1404 }
1405 brelse (bh);
1406 ext2_set_inode_flags(inode);
1407 unlock_new_inode(inode);
1408 return inode;
1409
1410bad_inode:
1411 iget_failed(inode);
1412 return ERR_PTR(ret);
1413}
1414
1415static int __ext2_write_inode(struct inode *inode, int do_sync)
1416{
1417 struct ext2_inode_info *ei = EXT2_I(inode);
1418 struct super_block *sb = inode->i_sb;
1419 ino_t ino = inode->i_ino;
1420 uid_t uid = i_uid_read(inode);
1421 gid_t gid = i_gid_read(inode);
1422 struct buffer_head * bh;
1423 struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
1424 int n;
1425 int err = 0;
1426
1427 if (IS_ERR(raw_inode))
1428 return -EIO;
1429
1430 /* For fields not not tracking in the in-memory inode,
1431 * initialise them to zero for new inodes. */
1432 if (ei->i_state & EXT2_STATE_NEW)
1433 memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size);
1434
1435 ext2_get_inode_flags(ei);
1436 raw_inode->i_mode = cpu_to_le16(inode->i_mode);
1437 if (!(test_opt(sb, NO_UID32))) {
1438 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
1439 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(gid));
1440/*
1441 * Fix up interoperability with old kernels. Otherwise, old inodes get
1442 * re-used with the upper 16 bits of the uid/gid intact
1443 */
1444 if (!ei->i_dtime) {
1445 raw_inode->i_uid_high = cpu_to_le16(high_16_bits(uid));
1446 raw_inode->i_gid_high = cpu_to_le16(high_16_bits(gid));
1447 } else {
1448 raw_inode->i_uid_high = 0;
1449 raw_inode->i_gid_high = 0;
1450 }
1451 } else {
1452 raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(uid));
1453 raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid));
1454 raw_inode->i_uid_high = 0;
1455 raw_inode->i_gid_high = 0;
1456 }
1457 raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
1458 raw_inode->i_size = cpu_to_le32(inode->i_size);
1459 raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
1460 raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
1461 raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
1462
1463 raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
1464 raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
1465 raw_inode->i_flags = cpu_to_le32(ei->i_flags);
1466 raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
1467 raw_inode->i_frag = ei->i_frag_no;
1468 raw_inode->i_fsize = ei->i_frag_size;
1469 raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
1470 if (!S_ISREG(inode->i_mode))
1471 raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
1472 else {
1473 raw_inode->i_size_high = cpu_to_le32(inode->i_size >> 32);
1474 if (inode->i_size > 0x7fffffffULL) {
1475 if (!EXT2_HAS_RO_COMPAT_FEATURE(sb,
1476 EXT2_FEATURE_RO_COMPAT_LARGE_FILE) ||
1477 EXT2_SB(sb)->s_es->s_rev_level ==
1478 cpu_to_le32(EXT2_GOOD_OLD_REV)) {
1479 /* If this is the first large file
1480 * created, add a flag to the superblock.
1481 */
1482 spin_lock(&EXT2_SB(sb)->s_lock);
1483 ext2_update_dynamic_rev(sb);
1484 EXT2_SET_RO_COMPAT_FEATURE(sb,
1485 EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
1486 spin_unlock(&EXT2_SB(sb)->s_lock);
1487 ext2_write_super(sb);
1488 }
1489 }
1490 }
1491
1492 raw_inode->i_generation = cpu_to_le32(inode->i_generation);
1493 if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
1494 if (old_valid_dev(inode->i_rdev)) {
1495 raw_inode->i_block[0] =
1496 cpu_to_le32(old_encode_dev(inode->i_rdev));
1497 raw_inode->i_block[1] = 0;
1498 } else {
1499 raw_inode->i_block[0] = 0;
1500 raw_inode->i_block[1] =
1501 cpu_to_le32(new_encode_dev(inode->i_rdev));
1502 raw_inode->i_block[2] = 0;
1503 }
1504 } else for (n = 0; n < EXT2_N_BLOCKS; n++)
1505 raw_inode->i_block[n] = ei->i_data[n];
1506 mark_buffer_dirty(bh);
1507 if (do_sync) {
1508 sync_dirty_buffer(bh);
1509 if (buffer_req(bh) && !buffer_uptodate(bh)) {
1510 printk ("IO error syncing ext2 inode [%s:%08lx]\n",
1511 sb->s_id, (unsigned long) ino);
1512 err = -EIO;
1513 }
1514 }
1515 ei->i_state &= ~EXT2_STATE_NEW;
1516 brelse (bh);
1517 return err;
1518}
1519
1520int ext2_write_inode(struct inode *inode, struct writeback_control *wbc)
1521{
1522 return __ext2_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
1523}
1524
1525int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
1526{
1527 struct inode *inode = dentry->d_inode;
1528 int error;
1529
1530 error = inode_change_ok(inode, iattr);
1531 if (error)
1532 return error;
1533
1534 if (is_quota_modification(inode, iattr))
1535 dquot_initialize(inode);
1536 if ((iattr->ia_valid & ATTR_UID && !uid_eq(iattr->ia_uid, inode->i_uid)) ||
1537 (iattr->ia_valid & ATTR_GID && !gid_eq(iattr->ia_gid, inode->i_gid))) {
1538 error = dquot_transfer(inode, iattr);
1539 if (error)
1540 return error;
1541 }
1542 if (iattr->ia_valid & ATTR_SIZE && iattr->ia_size != inode->i_size) {
1543 error = ext2_setsize(inode, iattr->ia_size);
1544 if (error)
1545 return error;
1546 }
1547 setattr_copy(inode, iattr);
1548 if (iattr->ia_valid & ATTR_MODE)
1549 error = ext2_acl_chmod(inode);
1550 mark_inode_dirty(inode);
1551
1552 return error;
1553}