1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/fs/ext2/inode.c
4 *
5 * Copyright (C) 1992, 1993, 1994, 1995
6 * Remy Card (card@masi.ibp.fr)
7 * Laboratoire MASI - Institut Blaise Pascal
8 * Universite Pierre et Marie Curie (Paris VI)
9 *
10 * from
11 *
12 * linux/fs/minix/inode.c
13 *
14 * Copyright (C) 1991, 1992 Linus Torvalds
15 *
16 * Goal-directed block allocation by Stephen Tweedie
17 * (sct@dcs.ed.ac.uk), 1993, 1998
18 * Big-endian to little-endian byte-swapping/bitmaps by
19 * David S. Miller (davem@caip.rutgers.edu), 1995
20 * 64-bit file support on 64-bit platforms by Jakub Jelinek
21 * (jj@sunsite.ms.mff.cuni.cz)
22 *
23 * Assorted race fixes, rewrite of ext2_get_block() by Al Viro, 2000
24 */
25
26 #include <linux/time.h>
27 #include <linux/highuid.h>
28 #include <linux/pagemap.h>
29 #include <linux/dax.h>
30 #include <linux/blkdev.h>
31 #include <linux/quotaops.h>
32 #include <linux/writeback.h>
33 #include <linux/buffer_head.h>
34 #include <linux/mpage.h>
35 #include <linux/fiemap.h>
36 #include <linux/iomap.h>
37 #include <linux/namei.h>
38 #include <linux/uio.h>
39 #include "ext2.h"
40 #include "acl.h"
41 #include "xattr.h"
42
43 static int __ext2_write_inode(struct inode *inode, int do_sync);
44
45 /*
46 * Test whether an inode is a fast symlink.
47 */
ext2_inode_is_fast_symlink(struct inode * inode)48 static inline int ext2_inode_is_fast_symlink(struct inode *inode)
49 {
50 int ea_blocks = EXT2_I(inode)->i_file_acl ?
51 (inode->i_sb->s_blocksize >> 9) : 0;
52
53 return (S_ISLNK(inode->i_mode) &&
54 inode->i_blocks - ea_blocks == 0);
55 }
56
57 static void ext2_truncate_blocks(struct inode *inode, loff_t offset);
58
ext2_write_failed(struct address_space * mapping,loff_t to)59 void ext2_write_failed(struct address_space *mapping, loff_t to)
60 {
61 struct inode *inode = mapping->host;
62
63 if (to > inode->i_size) {
64 truncate_pagecache(inode, inode->i_size);
65 ext2_truncate_blocks(inode, inode->i_size);
66 }
67 }
68
69 /*
70 * Called at the last iput() if i_nlink is zero.
71 */
ext2_evict_inode(struct inode * inode)72 void ext2_evict_inode(struct inode * inode)
73 {
74 struct ext2_block_alloc_info *rsv;
75 int want_delete = 0;
76
77 if (!inode->i_nlink && !is_bad_inode(inode)) {
78 want_delete = 1;
79 dquot_initialize(inode);
80 } else {
81 dquot_drop(inode);
82 }
83
84 truncate_inode_pages_final(&inode->i_data);
85
86 if (want_delete) {
87 sb_start_intwrite(inode->i_sb);
88 /* set dtime */
89 EXT2_I(inode)->i_dtime = ktime_get_real_seconds();
90 mark_inode_dirty(inode);
91 __ext2_write_inode(inode, inode_needs_sync(inode));
92 /* truncate to 0 */
93 inode->i_size = 0;
94 if (inode->i_blocks)
95 ext2_truncate_blocks(inode, 0);
96 ext2_xattr_delete_inode(inode);
97 }
98
99 invalidate_inode_buffers(inode);
100 clear_inode(inode);
101
102 ext2_discard_reservation(inode);
103 rsv = EXT2_I(inode)->i_block_alloc_info;
104 EXT2_I(inode)->i_block_alloc_info = NULL;
105 if (unlikely(rsv))
106 kfree(rsv);
107
108 if (want_delete) {
109 ext2_free_inode(inode);
110 sb_end_intwrite(inode->i_sb);
111 }
112 }
113
114 typedef struct {
115 __le32 *p;
116 __le32 key;
117 struct buffer_head *bh;
118 } Indirect;
119
add_chain(Indirect * p,struct buffer_head * bh,__le32 * v)120 static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
121 {
122 p->key = *(p->p = v);
123 p->bh = bh;
124 }
125
verify_chain(Indirect * from,Indirect * to)126 static inline int verify_chain(Indirect *from, Indirect *to)
127 {
128 while (from <= to && from->key == *from->p)
129 from++;
130 return (from > to);
131 }
132
133 /**
134 * ext2_block_to_path - parse the block number into array of offsets
135 * @inode: inode in question (we are only interested in its superblock)
136 * @i_block: block number to be parsed
137 * @offsets: array to store the offsets in
138 * @boundary: set this non-zero if the referred-to block is likely to be
139 * followed (on disk) by an indirect block.
140 * To store the locations of file's data ext2 uses a data structure common
141 * for UNIX filesystems - tree of pointers anchored in the inode, with
142 * data blocks at leaves and indirect blocks in intermediate nodes.
143 * This function translates the block number into path in that tree -
144 * return value is the path length and @offsets[n] is the offset of
145 * pointer to (n+1)th node in the nth one. If @block is out of range
146 * (negative or too large) warning is printed and zero returned.
147 *
148 * Note: function doesn't find node addresses, so no IO is needed. All
149 * we need to know is the capacity of indirect blocks (taken from the
150 * inode->i_sb).
151 */
152
153 /*
154 * Portability note: the last comparison (check that we fit into triple
155 * indirect block) is spelled differently, because otherwise on an
156 * architecture with 32-bit longs and 8Kb pages we might get into trouble
157 * if our filesystem had 8Kb blocks. We might use long long, but that would
158 * kill us on x86. Oh, well, at least the sign propagation does not matter -
159 * i_block would have to be negative in the very beginning, so we would not
160 * get there at all.
161 */
162
ext2_block_to_path(struct inode * inode,long i_block,int offsets[4],int * boundary)163 static int ext2_block_to_path(struct inode *inode,
164 long i_block, int offsets[4], int *boundary)
165 {
166 int ptrs = EXT2_ADDR_PER_BLOCK(inode->i_sb);
167 int ptrs_bits = EXT2_ADDR_PER_BLOCK_BITS(inode->i_sb);
168 const long direct_blocks = EXT2_NDIR_BLOCKS,
169 indirect_blocks = ptrs,
170 double_blocks = (1 << (ptrs_bits * 2));
171 int n = 0;
172 int final = 0;
173
174 if (i_block < 0) {
175 ext2_msg(inode->i_sb, KERN_WARNING,
176 "warning: %s: block < 0", __func__);
177 } else if (i_block < direct_blocks) {
178 offsets[n++] = i_block;
179 final = direct_blocks;
180 } else if ( (i_block -= direct_blocks) < indirect_blocks) {
181 offsets[n++] = EXT2_IND_BLOCK;
182 offsets[n++] = i_block;
183 final = ptrs;
184 } else if ((i_block -= indirect_blocks) < double_blocks) {
185 offsets[n++] = EXT2_DIND_BLOCK;
186 offsets[n++] = i_block >> ptrs_bits;
187 offsets[n++] = i_block & (ptrs - 1);
188 final = ptrs;
189 } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
190 offsets[n++] = EXT2_TIND_BLOCK;
191 offsets[n++] = i_block >> (ptrs_bits * 2);
192 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
193 offsets[n++] = i_block & (ptrs - 1);
194 final = ptrs;
195 } else {
196 ext2_msg(inode->i_sb, KERN_WARNING,
197 "warning: %s: block is too big", __func__);
198 }
199 if (boundary)
200 *boundary = final - 1 - (i_block & (ptrs - 1));
201
202 return n;
203 }
204
205 /**
206 * ext2_get_branch - read the chain of indirect blocks leading to data
207 * @inode: inode in question
208 * @depth: depth of the chain (1 - direct pointer, etc.)
209 * @offsets: offsets of pointers in inode/indirect blocks
210 * @chain: place to store the result
211 * @err: here we store the error value
212 *
213 * Function fills the array of triples <key, p, bh> and returns %NULL
214 * if everything went OK or the pointer to the last filled triple
215 * (incomplete one) otherwise. Upon the return chain[i].key contains
216 * the number of (i+1)-th block in the chain (as it is stored in memory,
217 * i.e. little-endian 32-bit), chain[i].p contains the address of that
218 * number (it points into struct inode for i==0 and into the bh->b_data
219 * for i>0) and chain[i].bh points to the buffer_head of i-th indirect
220 * block for i>0 and NULL for i==0. In other words, it holds the block
221 * numbers of the chain, addresses they were taken from (and where we can
222 * verify that chain did not change) and buffer_heads hosting these
223 * numbers.
224 *
225 * Function stops when it stumbles upon zero pointer (absent block)
226 * (pointer to last triple returned, *@err == 0)
227 * or when it gets an IO error reading an indirect block
228 * (ditto, *@err == -EIO)
229 * or when it notices that chain had been changed while it was reading
230 * (ditto, *@err == -EAGAIN)
231 * or when it reads all @depth-1 indirect blocks successfully and finds
232 * the whole chain, all way to the data (returns %NULL, *err == 0).
233 */
ext2_get_branch(struct inode * inode,int depth,int * offsets,Indirect chain[4],int * err)234 static Indirect *ext2_get_branch(struct inode *inode,
235 int depth,
236 int *offsets,
237 Indirect chain[4],
238 int *err)
239 {
240 struct super_block *sb = inode->i_sb;
241 Indirect *p = chain;
242 struct buffer_head *bh;
243
244 *err = 0;
245 /* i_data is not going away, no lock needed */
246 add_chain (chain, NULL, EXT2_I(inode)->i_data + *offsets);
247 if (!p->key)
248 goto no_block;
249 while (--depth) {
250 bh = sb_bread(sb, le32_to_cpu(p->key));
251 if (!bh)
252 goto failure;
253 read_lock(&EXT2_I(inode)->i_meta_lock);
254 if (!verify_chain(chain, p))
255 goto changed;
256 add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
257 read_unlock(&EXT2_I(inode)->i_meta_lock);
258 if (!p->key)
259 goto no_block;
260 }
261 return NULL;
262
263 changed:
264 read_unlock(&EXT2_I(inode)->i_meta_lock);
265 brelse(bh);
266 *err = -EAGAIN;
267 goto no_block;
268 failure:
269 *err = -EIO;
270 no_block:
271 return p;
272 }
273
274 /**
275 * ext2_find_near - find a place for allocation with sufficient locality
276 * @inode: owner
277 * @ind: descriptor of indirect block.
278 *
279 * This function returns the preferred place for block allocation.
280 * It is used when heuristic for sequential allocation fails.
281 * Rules are:
282 * + if there is a block to the left of our position - allocate near it.
283 * + if pointer will live in indirect block - allocate near that block.
284 * + if pointer will live in inode - allocate in the same cylinder group.
285 *
286 * In the latter case we colour the starting block by the callers PID to
287 * prevent it from clashing with concurrent allocations for a different inode
288 * in the same block group. The PID is used here so that functionally related
289 * files will be close-by on-disk.
290 *
291 * Caller must make sure that @ind is valid and will stay that way.
292 */
293
ext2_find_near(struct inode * inode,Indirect * ind)294 static ext2_fsblk_t ext2_find_near(struct inode *inode, Indirect *ind)
295 {
296 struct ext2_inode_info *ei = EXT2_I(inode);
297 __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
298 __le32 *p;
299 ext2_fsblk_t bg_start;
300 ext2_fsblk_t colour;
301
302 /* Try to find previous block */
303 for (p = ind->p - 1; p >= start; p--)
304 if (*p)
305 return le32_to_cpu(*p);
306
307 /* No such thing, so let's try location of indirect block */
308 if (ind->bh)
309 return ind->bh->b_blocknr;
310
311 /*
312 * It is going to be referred from inode itself? OK, just put it into
313 * the same cylinder group then.
314 */
315 bg_start = ext2_group_first_block_no(inode->i_sb, ei->i_block_group);
316 colour = (current->pid % 16) *
317 (EXT2_BLOCKS_PER_GROUP(inode->i_sb) / 16);
318 return bg_start + colour;
319 }
320
321 /**
322 * ext2_find_goal - find a preferred place for allocation.
323 * @inode: owner
324 * @block: block we want
325 * @partial: pointer to the last triple within a chain
326 *
327 * Returns preferred place for a block (the goal).
328 */
329
ext2_find_goal(struct inode * inode,long block,Indirect * partial)330 static inline ext2_fsblk_t ext2_find_goal(struct inode *inode, long block,
331 Indirect *partial)
332 {
333 struct ext2_block_alloc_info *block_i;
334
335 block_i = EXT2_I(inode)->i_block_alloc_info;
336
337 /*
338 * try the heuristic for sequential allocation,
339 * failing that at least try to get decent locality.
340 */
341 if (block_i && (block == block_i->last_alloc_logical_block + 1)
342 && (block_i->last_alloc_physical_block != 0)) {
343 return block_i->last_alloc_physical_block + 1;
344 }
345
346 return ext2_find_near(inode, partial);
347 }
348
349 /**
350 * ext2_blks_to_allocate: Look up the block map and count the number
351 * of direct blocks need to be allocated for the given branch.
352 *
353 * @branch: chain of indirect blocks
354 * @k: number of blocks need for indirect blocks
355 * @blks: number of data blocks to be mapped.
356 * @blocks_to_boundary: the offset in the indirect block
357 *
358 * return the number of direct blocks to allocate.
359 */
360 static int
ext2_blks_to_allocate(Indirect * branch,int k,unsigned long blks,int blocks_to_boundary)361 ext2_blks_to_allocate(Indirect * branch, int k, unsigned long blks,
362 int blocks_to_boundary)
363 {
364 unsigned long count = 0;
365
366 /*
367 * Simple case, [t,d]Indirect block(s) has not allocated yet
368 * then it's clear blocks on that path have not allocated
369 */
370 if (k > 0) {
371 /* right now don't hanel cross boundary allocation */
372 if (blks < blocks_to_boundary + 1)
373 count += blks;
374 else
375 count += blocks_to_boundary + 1;
376 return count;
377 }
378
379 count++;
380 while (count < blks && count <= blocks_to_boundary
381 && le32_to_cpu(*(branch[0].p + count)) == 0) {
382 count++;
383 }
384 return count;
385 }
386
387 /**
388 * ext2_alloc_blocks: Allocate multiple blocks needed for a branch.
389 * @inode: Owner.
390 * @goal: Preferred place for allocation.
391 * @indirect_blks: The number of blocks needed to allocate for indirect blocks.
392 * @blks: The number of blocks need to allocate for direct blocks.
393 * @new_blocks: On return it will store the new block numbers for
394 * the indirect blocks(if needed) and the first direct block.
395 * @err: Error pointer.
396 *
397 * Return: Number of blocks allocated.
398 */
ext2_alloc_blocks(struct inode * inode,ext2_fsblk_t goal,int indirect_blks,int blks,ext2_fsblk_t new_blocks[4],int * err)399 static int ext2_alloc_blocks(struct inode *inode,
400 ext2_fsblk_t goal, int indirect_blks, int blks,
401 ext2_fsblk_t new_blocks[4], int *err)
402 {
403 int target, i;
404 unsigned long count = 0;
405 int index = 0;
406 ext2_fsblk_t current_block = 0;
407 int ret = 0;
408
409 /*
410 * Here we try to allocate the requested multiple blocks at once,
411 * on a best-effort basis.
412 * To build a branch, we should allocate blocks for
413 * the indirect blocks(if not allocated yet), and at least
414 * the first direct block of this branch. That's the
415 * minimum number of blocks need to allocate(required)
416 */
417 target = blks + indirect_blks;
418
419 while (1) {
420 count = target;
421 /* allocating blocks for indirect blocks and direct blocks */
422 current_block = ext2_new_blocks(inode, goal, &count, err, 0);
423 if (*err)
424 goto failed_out;
425
426 target -= count;
427 /* allocate blocks for indirect blocks */
428 while (index < indirect_blks && count) {
429 new_blocks[index++] = current_block++;
430 count--;
431 }
432
433 if (count > 0)
434 break;
435 }
436
437 /* save the new block number for the first direct block */
438 new_blocks[index] = current_block;
439
440 /* total number of blocks allocated for direct blocks */
441 ret = count;
442 *err = 0;
443 return ret;
444 failed_out:
445 for (i = 0; i <index; i++)
446 ext2_free_blocks(inode, new_blocks[i], 1);
447 if (index)
448 mark_inode_dirty(inode);
449 return ret;
450 }
451
452 /**
453 * ext2_alloc_branch - allocate and set up a chain of blocks.
454 * @inode: owner
455 * @indirect_blks: depth of the chain (number of blocks to allocate)
456 * @blks: number of allocated direct blocks
457 * @goal: preferred place for allocation
458 * @offsets: offsets (in the blocks) to store the pointers to next.
459 * @branch: place to store the chain in.
460 *
461 * This function allocates @num blocks, zeroes out all but the last one,
462 * links them into chain and (if we are synchronous) writes them to disk.
463 * In other words, it prepares a branch that can be spliced onto the
464 * inode. It stores the information about that chain in the branch[], in
465 * the same format as ext2_get_branch() would do. We are calling it after
466 * we had read the existing part of chain and partial points to the last
467 * triple of that (one with zero ->key). Upon the exit we have the same
468 * picture as after the successful ext2_get_block(), except that in one
469 * place chain is disconnected - *branch->p is still zero (we did not
470 * set the last link), but branch->key contains the number that should
471 * be placed into *branch->p to fill that gap.
472 *
473 * If allocation fails we free all blocks we've allocated (and forget
474 * their buffer_heads) and return the error value the from failed
475 * ext2_alloc_block() (normally -ENOSPC). Otherwise we set the chain
476 * as described above and return 0.
477 */
478
ext2_alloc_branch(struct inode * inode,int indirect_blks,int * blks,ext2_fsblk_t goal,int * offsets,Indirect * branch)479 static int ext2_alloc_branch(struct inode *inode,
480 int indirect_blks, int *blks, ext2_fsblk_t goal,
481 int *offsets, Indirect *branch)
482 {
483 int blocksize = inode->i_sb->s_blocksize;
484 int i, n = 0;
485 int err = 0;
486 struct buffer_head *bh;
487 int num;
488 ext2_fsblk_t new_blocks[4];
489 ext2_fsblk_t current_block;
490
491 num = ext2_alloc_blocks(inode, goal, indirect_blks,
492 *blks, new_blocks, &err);
493 if (err)
494 return err;
495
496 branch[0].key = cpu_to_le32(new_blocks[0]);
497 /*
498 * metadata blocks and data blocks are allocated.
499 */
500 for (n = 1; n <= indirect_blks; n++) {
501 /*
502 * Get buffer_head for parent block, zero it out
503 * and set the pointer to new one, then send
504 * parent to disk.
505 */
506 bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
507 if (unlikely(!bh)) {
508 err = -ENOMEM;
509 goto failed;
510 }
511 branch[n].bh = bh;
512 lock_buffer(bh);
513 memset(bh->b_data, 0, blocksize);
514 branch[n].p = (__le32 *) bh->b_data + offsets[n];
515 branch[n].key = cpu_to_le32(new_blocks[n]);
516 *branch[n].p = branch[n].key;
517 if ( n == indirect_blks) {
518 current_block = new_blocks[n];
519 /*
520 * End of chain, update the last new metablock of
521 * the chain to point to the new allocated
522 * data blocks numbers
523 */
524 for (i=1; i < num; i++)
525 *(branch[n].p + i) = cpu_to_le32(++current_block);
526 }
527 set_buffer_uptodate(bh);
528 unlock_buffer(bh);
529 mark_buffer_dirty_inode(bh, inode);
530 /* We used to sync bh here if IS_SYNC(inode).
531 * But we now rely upon generic_write_sync()
532 * and b_inode_buffers. But not for directories.
533 */
534 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
535 sync_dirty_buffer(bh);
536 }
537 *blks = num;
538 return err;
539
540 failed:
541 for (i = 1; i < n; i++)
542 bforget(branch[i].bh);
543 for (i = 0; i < indirect_blks; i++)
544 ext2_free_blocks(inode, new_blocks[i], 1);
545 ext2_free_blocks(inode, new_blocks[i], num);
546 return err;
547 }
548
549 /**
550 * ext2_splice_branch - splice the allocated branch onto inode.
551 * @inode: owner
552 * @block: (logical) number of block we are adding
553 * @where: location of missing link
554 * @num: number of indirect blocks we are adding
555 * @blks: number of direct blocks we are adding
556 *
557 * This function fills the missing link and does all housekeeping needed in
558 * inode (->i_blocks, etc.). In case of success we end up with the full
559 * chain to new block and return 0.
560 */
ext2_splice_branch(struct inode * inode,long block,Indirect * where,int num,int blks)561 static void ext2_splice_branch(struct inode *inode,
562 long block, Indirect *where, int num, int blks)
563 {
564 int i;
565 struct ext2_block_alloc_info *block_i;
566 ext2_fsblk_t current_block;
567
568 block_i = EXT2_I(inode)->i_block_alloc_info;
569
570 /* XXX LOCKING probably should have i_meta_lock ?*/
571 /* That's it */
572
573 *where->p = where->key;
574
575 /*
576 * Update the host buffer_head or inode to point to more just allocated
577 * direct blocks blocks
578 */
579 if (num == 0 && blks > 1) {
580 current_block = le32_to_cpu(where->key) + 1;
581 for (i = 1; i < blks; i++)
582 *(where->p + i ) = cpu_to_le32(current_block++);
583 }
584
585 /*
586 * update the most recently allocated logical & physical block
587 * in i_block_alloc_info, to assist find the proper goal block for next
588 * allocation
589 */
590 if (block_i) {
591 block_i->last_alloc_logical_block = block + blks - 1;
592 block_i->last_alloc_physical_block =
593 le32_to_cpu(where[num].key) + blks - 1;
594 }
595
596 /* We are done with atomic stuff, now do the rest of housekeeping */
597
598 /* had we spliced it onto indirect block? */
599 if (where->bh)
600 mark_buffer_dirty_inode(where->bh, inode);
601
602 inode_set_ctime_current(inode);
603 mark_inode_dirty(inode);
604 }
605
606 /*
607 * Allocation strategy is simple: if we have to allocate something, we will
608 * have to go the whole way to leaf. So let's do it before attaching anything
609 * to tree, set linkage between the newborn blocks, write them if sync is
610 * required, recheck the path, free and repeat if check fails, otherwise
611 * set the last missing link (that will protect us from any truncate-generated
612 * removals - all blocks on the path are immune now) and possibly force the
613 * write on the parent block.
614 * That has a nice additional property: no special recovery from the failed
615 * allocations is needed - we simply release blocks and do not touch anything
616 * reachable from inode.
617 *
618 * `handle' can be NULL if create == 0.
619 *
620 * return > 0, # of blocks mapped or allocated.
621 * return = 0, if plain lookup failed.
622 * return < 0, error case.
623 */
ext2_get_blocks(struct inode * inode,sector_t iblock,unsigned long maxblocks,u32 * bno,bool * new,bool * boundary,int create)624 static int ext2_get_blocks(struct inode *inode,
625 sector_t iblock, unsigned long maxblocks,
626 u32 *bno, bool *new, bool *boundary,
627 int create)
628 {
629 int err;
630 int offsets[4];
631 Indirect chain[4];
632 Indirect *partial;
633 ext2_fsblk_t goal;
634 int indirect_blks;
635 int blocks_to_boundary = 0;
636 int depth;
637 struct ext2_inode_info *ei = EXT2_I(inode);
638 int count = 0;
639 ext2_fsblk_t first_block = 0;
640
641 BUG_ON(maxblocks == 0);
642
643 depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
644
645 if (depth == 0)
646 return -EIO;
647
648 partial = ext2_get_branch(inode, depth, offsets, chain, &err);
649 /* Simplest case - block found, no allocation needed */
650 if (!partial) {
651 first_block = le32_to_cpu(chain[depth - 1].key);
652 count++;
653 /*map more blocks*/
654 while (count < maxblocks && count <= blocks_to_boundary) {
655 ext2_fsblk_t blk;
656
657 if (!verify_chain(chain, chain + depth - 1)) {
658 /*
659 * Indirect block might be removed by
660 * truncate while we were reading it.
661 * Handling of that case: forget what we've
662 * got now, go to reread.
663 */
664 err = -EAGAIN;
665 count = 0;
666 partial = chain + depth - 1;
667 break;
668 }
669 blk = le32_to_cpu(*(chain[depth-1].p + count));
670 if (blk == first_block + count)
671 count++;
672 else
673 break;
674 }
675 if (err != -EAGAIN)
676 goto got_it;
677 }
678
679 /* Next simple case - plain lookup or failed read of indirect block */
680 if (!create || err == -EIO)
681 goto cleanup;
682
683 mutex_lock(&ei->truncate_mutex);
684 /*
685 * If the indirect block is missing while we are reading
686 * the chain(ext2_get_branch() returns -EAGAIN err), or
687 * if the chain has been changed after we grab the semaphore,
688 * (either because another process truncated this branch, or
689 * another get_block allocated this branch) re-grab the chain to see if
690 * the request block has been allocated or not.
691 *
692 * Since we already block the truncate/other get_block
693 * at this point, we will have the current copy of the chain when we
694 * splice the branch into the tree.
695 */
696 if (err == -EAGAIN || !verify_chain(chain, partial)) {
697 while (partial > chain) {
698 brelse(partial->bh);
699 partial--;
700 }
701 partial = ext2_get_branch(inode, depth, offsets, chain, &err);
702 if (!partial) {
703 count++;
704 mutex_unlock(&ei->truncate_mutex);
705 goto got_it;
706 }
707
708 if (err) {
709 mutex_unlock(&ei->truncate_mutex);
710 goto cleanup;
711 }
712 }
713
714 /*
715 * Okay, we need to do block allocation. Lazily initialize the block
716 * allocation info here if necessary
717 */
718 if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
719 ext2_init_block_alloc_info(inode);
720
721 goal = ext2_find_goal(inode, iblock, partial);
722
723 /* the number of blocks need to allocate for [d,t]indirect blocks */
724 indirect_blks = (chain + depth) - partial - 1;
725 /*
726 * Next look up the indirect map to count the total number of
727 * direct blocks to allocate for this branch.
728 */
729 count = ext2_blks_to_allocate(partial, indirect_blks,
730 maxblocks, blocks_to_boundary);
731 /*
732 * XXX ???? Block out ext2_truncate while we alter the tree
733 */
734 err = ext2_alloc_branch(inode, indirect_blks, &count, goal,
735 offsets + (partial - chain), partial);
736
737 if (err) {
738 mutex_unlock(&ei->truncate_mutex);
739 goto cleanup;
740 }
741
742 if (IS_DAX(inode)) {
743 /*
744 * We must unmap blocks before zeroing so that writeback cannot
745 * overwrite zeros with stale data from block device page cache.
746 */
747 clean_bdev_aliases(inode->i_sb->s_bdev,
748 le32_to_cpu(chain[depth-1].key),
749 count);
750 /*
751 * block must be initialised before we put it in the tree
752 * so that it's not found by another thread before it's
753 * initialised
754 */
755 err = sb_issue_zeroout(inode->i_sb,
756 le32_to_cpu(chain[depth-1].key), count,
757 GFP_KERNEL);
758 if (err) {
759 mutex_unlock(&ei->truncate_mutex);
760 goto cleanup;
761 }
762 }
763 *new = true;
764
765 ext2_splice_branch(inode, iblock, partial, indirect_blks, count);
766 mutex_unlock(&ei->truncate_mutex);
767 got_it:
768 if (count > blocks_to_boundary)
769 *boundary = true;
770 err = count;
771 /* Clean up and exit */
772 partial = chain + depth - 1; /* the whole chain */
773 cleanup:
774 while (partial > chain) {
775 brelse(partial->bh);
776 partial--;
777 }
778 if (err > 0)
779 *bno = le32_to_cpu(chain[depth-1].key);
780 return err;
781 }
782
ext2_get_block(struct inode * inode,sector_t iblock,struct buffer_head * bh_result,int create)783 int ext2_get_block(struct inode *inode, sector_t iblock,
784 struct buffer_head *bh_result, int create)
785 {
786 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
787 bool new = false, boundary = false;
788 u32 bno;
789 int ret;
790
791 ret = ext2_get_blocks(inode, iblock, max_blocks, &bno, &new, &boundary,
792 create);
793 if (ret <= 0)
794 return ret;
795
796 map_bh(bh_result, inode->i_sb, bno);
797 bh_result->b_size = (ret << inode->i_blkbits);
798 if (new)
799 set_buffer_new(bh_result);
800 if (boundary)
801 set_buffer_boundary(bh_result);
802 return 0;
803
804 }
805
ext2_iomap_begin(struct inode * inode,loff_t offset,loff_t length,unsigned flags,struct iomap * iomap,struct iomap * srcmap)806 static int ext2_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
807 unsigned flags, struct iomap *iomap, struct iomap *srcmap)
808 {
809 unsigned int blkbits = inode->i_blkbits;
810 unsigned long first_block = offset >> blkbits;
811 unsigned long max_blocks = (length + (1 << blkbits) - 1) >> blkbits;
812 struct ext2_sb_info *sbi = EXT2_SB(inode->i_sb);
813 bool new = false, boundary = false;
814 u32 bno;
815 int ret;
816 bool create = flags & IOMAP_WRITE;
817
818 /*
819 * For writes that could fill holes inside i_size on a
820 * DIO_SKIP_HOLES filesystem we forbid block creations: only
821 * overwrites are permitted.
822 */
823 if ((flags & IOMAP_DIRECT) &&
824 (first_block << blkbits) < i_size_read(inode))
825 create = 0;
826
827 /*
828 * Writes that span EOF might trigger an IO size update on completion,
829 * so consider them to be dirty for the purposes of O_DSYNC even if
830 * there is no other metadata changes pending or have been made here.
831 */
832 if ((flags & IOMAP_WRITE) && offset + length > i_size_read(inode))
833 iomap->flags |= IOMAP_F_DIRTY;
834
835 ret = ext2_get_blocks(inode, first_block, max_blocks,
836 &bno, &new, &boundary, create);
837 if (ret < 0)
838 return ret;
839
840 iomap->flags = 0;
841 iomap->offset = (u64)first_block << blkbits;
842 if (flags & IOMAP_DAX)
843 iomap->dax_dev = sbi->s_daxdev;
844 else
845 iomap->bdev = inode->i_sb->s_bdev;
846
847 if (ret == 0) {
848 /*
849 * Switch to buffered-io for writing to holes in a non-extent
850 * based filesystem to avoid stale data exposure problem.
851 */
852 if (!create && (flags & IOMAP_WRITE) && (flags & IOMAP_DIRECT))
853 return -ENOTBLK;
854 iomap->type = IOMAP_HOLE;
855 iomap->addr = IOMAP_NULL_ADDR;
856 iomap->length = 1 << blkbits;
857 } else {
858 iomap->type = IOMAP_MAPPED;
859 iomap->addr = (u64)bno << blkbits;
860 if (flags & IOMAP_DAX)
861 iomap->addr += sbi->s_dax_part_off;
862 iomap->length = (u64)ret << blkbits;
863 iomap->flags |= IOMAP_F_MERGED;
864 }
865
866 if (new)
867 iomap->flags |= IOMAP_F_NEW;
868 return 0;
869 }
870
871 static int
ext2_iomap_end(struct inode * inode,loff_t offset,loff_t length,ssize_t written,unsigned flags,struct iomap * iomap)872 ext2_iomap_end(struct inode *inode, loff_t offset, loff_t length,
873 ssize_t written, unsigned flags, struct iomap *iomap)
874 {
875 /*
876 * Switch to buffered-io in case of any error.
877 * Blocks allocated can be used by the buffered-io path.
878 */
879 if ((flags & IOMAP_DIRECT) && (flags & IOMAP_WRITE) && written == 0)
880 return -ENOTBLK;
881
882 if (iomap->type == IOMAP_MAPPED &&
883 written < length &&
884 (flags & IOMAP_WRITE))
885 ext2_write_failed(inode->i_mapping, offset + length);
886 return 0;
887 }
888
889 const struct iomap_ops ext2_iomap_ops = {
890 .iomap_begin = ext2_iomap_begin,
891 .iomap_end = ext2_iomap_end,
892 };
893
ext2_fiemap(struct inode * inode,struct fiemap_extent_info * fieinfo,u64 start,u64 len)894 int ext2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
895 u64 start, u64 len)
896 {
897 int ret;
898 loff_t i_size;
899
900 inode_lock(inode);
901 i_size = i_size_read(inode);
902 /*
903 * iomap_fiemap() returns EINVAL for 0 length. Make sure we don't trim
904 * length to 0 but still trim the range as much as possible since
905 * ext2_get_blocks() iterates unmapped space block by block which is
906 * slow.
907 */
908 if (i_size == 0)
909 i_size = 1;
910 len = min_t(u64, len, i_size);
911 ret = iomap_fiemap(inode, fieinfo, start, len, &ext2_iomap_ops);
912 inode_unlock(inode);
913
914 return ret;
915 }
916
ext2_read_folio(struct file * file,struct folio * folio)917 static int ext2_read_folio(struct file *file, struct folio *folio)
918 {
919 return mpage_read_folio(folio, ext2_get_block);
920 }
921
ext2_readahead(struct readahead_control * rac)922 static void ext2_readahead(struct readahead_control *rac)
923 {
924 mpage_readahead(rac, ext2_get_block);
925 }
926
927 static int
ext2_write_begin(const struct kiocb * iocb,struct address_space * mapping,loff_t pos,unsigned len,struct folio ** foliop,void ** fsdata)928 ext2_write_begin(const struct kiocb *iocb, struct address_space *mapping,
929 loff_t pos, unsigned len, struct folio **foliop, void **fsdata)
930 {
931 int ret;
932
933 ret = block_write_begin(mapping, pos, len, foliop, ext2_get_block);
934 if (ret < 0)
935 ext2_write_failed(mapping, pos + len);
936 return ret;
937 }
938
ext2_write_end(const struct kiocb * iocb,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct folio * folio,void * fsdata)939 static int ext2_write_end(const struct kiocb *iocb,
940 struct address_space *mapping,
941 loff_t pos, unsigned len, unsigned copied,
942 struct folio *folio, void *fsdata)
943 {
944 int ret;
945
946 ret = generic_write_end(iocb, mapping, pos, len, copied, folio, fsdata);
947 if (ret < len)
948 ext2_write_failed(mapping, pos + len);
949 return ret;
950 }
951
ext2_bmap(struct address_space * mapping,sector_t block)952 static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
953 {
954 return generic_block_bmap(mapping,block,ext2_get_block);
955 }
956
957 static int
ext2_writepages(struct address_space * mapping,struct writeback_control * wbc)958 ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
959 {
960 return mpage_writepages(mapping, wbc, ext2_get_block);
961 }
962
963 static int
ext2_dax_writepages(struct address_space * mapping,struct writeback_control * wbc)964 ext2_dax_writepages(struct address_space *mapping, struct writeback_control *wbc)
965 {
966 struct ext2_sb_info *sbi = EXT2_SB(mapping->host->i_sb);
967
968 return dax_writeback_mapping_range(mapping, sbi->s_daxdev, wbc);
969 }
970
971 const struct address_space_operations ext2_aops = {
972 .dirty_folio = block_dirty_folio,
973 .invalidate_folio = block_invalidate_folio,
974 .read_folio = ext2_read_folio,
975 .readahead = ext2_readahead,
976 .write_begin = ext2_write_begin,
977 .write_end = ext2_write_end,
978 .bmap = ext2_bmap,
979 .writepages = ext2_writepages,
980 .migrate_folio = buffer_migrate_folio,
981 .is_partially_uptodate = block_is_partially_uptodate,
982 .error_remove_folio = generic_error_remove_folio,
983 };
984
985 static const struct address_space_operations ext2_dax_aops = {
986 .writepages = ext2_dax_writepages,
987 .dirty_folio = noop_dirty_folio,
988 };
989
990 /*
991 * Probably it should be a library function... search for first non-zero word
992 * or memcmp with zero_page, whatever is better for particular architecture.
993 * Linus?
994 */
all_zeroes(__le32 * p,__le32 * q)995 static inline int all_zeroes(__le32 *p, __le32 *q)
996 {
997 while (p < q)
998 if (*p++)
999 return 0;
1000 return 1;
1001 }
1002
1003 /**
1004 * ext2_find_shared - find the indirect blocks for partial truncation.
1005 * @inode: inode in question
1006 * @depth: depth of the affected branch
1007 * @offsets: offsets of pointers in that branch (see ext2_block_to_path)
1008 * @chain: place to store the pointers to partial indirect blocks
1009 * @top: place to the (detached) top of branch
1010 *
1011 * This is a helper function used by ext2_truncate().
1012 *
1013 * When we do truncate() we may have to clean the ends of several indirect
1014 * blocks but leave the blocks themselves alive. Block is partially
1015 * truncated if some data below the new i_size is referred from it (and
1016 * it is on the path to the first completely truncated data block, indeed).
1017 * We have to free the top of that path along with everything to the right
1018 * of the path. Since no allocation past the truncation point is possible
1019 * until ext2_truncate() finishes, we may safely do the latter, but top
1020 * of branch may require special attention - pageout below the truncation
1021 * point might try to populate it.
1022 *
1023 * We atomically detach the top of branch from the tree, store the block
1024 * number of its root in *@top, pointers to buffer_heads of partially
1025 * truncated blocks - in @chain[].bh and pointers to their last elements
1026 * that should not be removed - in @chain[].p. Return value is the pointer
1027 * to last filled element of @chain.
1028 *
1029 * The work left to caller to do the actual freeing of subtrees:
1030 * a) free the subtree starting from *@top
1031 * b) free the subtrees whose roots are stored in
1032 * (@chain[i].p+1 .. end of @chain[i].bh->b_data)
1033 * c) free the subtrees growing from the inode past the @chain[0].p
1034 * (no partially truncated stuff there).
1035 */
1036
ext2_find_shared(struct inode * inode,int depth,int offsets[4],Indirect chain[4],__le32 * top)1037 static Indirect *ext2_find_shared(struct inode *inode,
1038 int depth,
1039 int offsets[4],
1040 Indirect chain[4],
1041 __le32 *top)
1042 {
1043 Indirect *partial, *p;
1044 int k, err;
1045
1046 *top = 0;
1047 for (k = depth; k > 1 && !offsets[k-1]; k--)
1048 ;
1049 partial = ext2_get_branch(inode, k, offsets, chain, &err);
1050 if (!partial)
1051 partial = chain + k-1;
1052 /*
1053 * If the branch acquired continuation since we've looked at it -
1054 * fine, it should all survive and (new) top doesn't belong to us.
1055 */
1056 write_lock(&EXT2_I(inode)->i_meta_lock);
1057 if (!partial->key && *partial->p) {
1058 write_unlock(&EXT2_I(inode)->i_meta_lock);
1059 goto no_top;
1060 }
1061 for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
1062 ;
1063 /*
1064 * OK, we've found the last block that must survive. The rest of our
1065 * branch should be detached before unlocking. However, if that rest
1066 * of branch is all ours and does not grow immediately from the inode
1067 * it's easier to cheat and just decrement partial->p.
1068 */
1069 if (p == chain + k - 1 && p > chain) {
1070 p->p--;
1071 } else {
1072 *top = *p->p;
1073 *p->p = 0;
1074 }
1075 write_unlock(&EXT2_I(inode)->i_meta_lock);
1076
1077 while(partial > p)
1078 {
1079 brelse(partial->bh);
1080 partial--;
1081 }
1082 no_top:
1083 return partial;
1084 }
1085
1086 /**
1087 * ext2_free_data - free a list of data blocks
1088 * @inode: inode we are dealing with
1089 * @p: array of block numbers
1090 * @q: points immediately past the end of array
1091 *
1092 * We are freeing all blocks referred from that array (numbers are
1093 * stored as little-endian 32-bit) and updating @inode->i_blocks
1094 * appropriately.
1095 */
ext2_free_data(struct inode * inode,__le32 * p,__le32 * q)1096 static inline void ext2_free_data(struct inode *inode, __le32 *p, __le32 *q)
1097 {
1098 ext2_fsblk_t block_to_free = 0, count = 0;
1099 ext2_fsblk_t nr;
1100
1101 for ( ; p < q ; p++) {
1102 nr = le32_to_cpu(*p);
1103 if (nr) {
1104 *p = 0;
1105 /* accumulate blocks to free if they're contiguous */
1106 if (count == 0)
1107 goto free_this;
1108 else if (block_to_free == nr - count)
1109 count++;
1110 else {
1111 ext2_free_blocks (inode, block_to_free, count);
1112 mark_inode_dirty(inode);
1113 free_this:
1114 block_to_free = nr;
1115 count = 1;
1116 }
1117 }
1118 }
1119 if (count > 0) {
1120 ext2_free_blocks (inode, block_to_free, count);
1121 mark_inode_dirty(inode);
1122 }
1123 }
1124
1125 /**
1126 * ext2_free_branches - free an array of branches
1127 * @inode: inode we are dealing with
1128 * @p: array of block numbers
1129 * @q: pointer immediately past the end of array
1130 * @depth: depth of the branches to free
1131 *
1132 * We are freeing all blocks referred from these branches (numbers are
1133 * stored as little-endian 32-bit) and updating @inode->i_blocks
1134 * appropriately.
1135 */
ext2_free_branches(struct inode * inode,__le32 * p,__le32 * q,int depth)1136 static void ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int depth)
1137 {
1138 struct buffer_head * bh;
1139 ext2_fsblk_t nr;
1140
1141 if (depth--) {
1142 int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1143 for ( ; p < q ; p++) {
1144 nr = le32_to_cpu(*p);
1145 if (!nr)
1146 continue;
1147 *p = 0;
1148 bh = sb_bread(inode->i_sb, nr);
1149 /*
1150 * A read failure? Report error and clear slot
1151 * (should be rare).
1152 */
1153 if (!bh) {
1154 ext2_error(inode->i_sb, "ext2_free_branches",
1155 "Read failure, inode=%ld, block=%ld",
1156 inode->i_ino, nr);
1157 continue;
1158 }
1159 ext2_free_branches(inode,
1160 (__le32*)bh->b_data,
1161 (__le32*)bh->b_data + addr_per_block,
1162 depth);
1163 bforget(bh);
1164 ext2_free_blocks(inode, nr, 1);
1165 mark_inode_dirty(inode);
1166 }
1167 } else
1168 ext2_free_data(inode, p, q);
1169 }
1170
1171 /* mapping->invalidate_lock must be held when calling this function */
__ext2_truncate_blocks(struct inode * inode,loff_t offset)1172 static void __ext2_truncate_blocks(struct inode *inode, loff_t offset)
1173 {
1174 __le32 *i_data = EXT2_I(inode)->i_data;
1175 struct ext2_inode_info *ei = EXT2_I(inode);
1176 int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1177 int offsets[4];
1178 Indirect chain[4];
1179 Indirect *partial;
1180 __le32 nr = 0;
1181 int n;
1182 long iblock;
1183 unsigned blocksize;
1184 blocksize = inode->i_sb->s_blocksize;
1185 iblock = (offset + blocksize-1) >> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
1186
1187 #ifdef CONFIG_FS_DAX
1188 WARN_ON(!rwsem_is_locked(&inode->i_mapping->invalidate_lock));
1189 #endif
1190
1191 n = ext2_block_to_path(inode, iblock, offsets, NULL);
1192 if (n == 0)
1193 return;
1194
1195 /*
1196 * From here we block out all ext2_get_block() callers who want to
1197 * modify the block allocation tree.
1198 */
1199 mutex_lock(&ei->truncate_mutex);
1200
1201 if (n == 1) {
1202 ext2_free_data(inode, i_data+offsets[0],
1203 i_data + EXT2_NDIR_BLOCKS);
1204 goto do_indirects;
1205 }
1206
1207 partial = ext2_find_shared(inode, n, offsets, chain, &nr);
1208 /* Kill the top of shared branch (already detached) */
1209 if (nr) {
1210 if (partial == chain)
1211 mark_inode_dirty(inode);
1212 else
1213 mark_buffer_dirty_inode(partial->bh, inode);
1214 ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
1215 }
1216 /* Clear the ends of indirect blocks on the shared branch */
1217 while (partial > chain) {
1218 ext2_free_branches(inode,
1219 partial->p + 1,
1220 (__le32*)partial->bh->b_data+addr_per_block,
1221 (chain+n-1) - partial);
1222 mark_buffer_dirty_inode(partial->bh, inode);
1223 brelse (partial->bh);
1224 partial--;
1225 }
1226 do_indirects:
1227 /* Kill the remaining (whole) subtrees */
1228 switch (offsets[0]) {
1229 default:
1230 nr = i_data[EXT2_IND_BLOCK];
1231 if (nr) {
1232 i_data[EXT2_IND_BLOCK] = 0;
1233 mark_inode_dirty(inode);
1234 ext2_free_branches(inode, &nr, &nr+1, 1);
1235 }
1236 fallthrough;
1237 case EXT2_IND_BLOCK:
1238 nr = i_data[EXT2_DIND_BLOCK];
1239 if (nr) {
1240 i_data[EXT2_DIND_BLOCK] = 0;
1241 mark_inode_dirty(inode);
1242 ext2_free_branches(inode, &nr, &nr+1, 2);
1243 }
1244 fallthrough;
1245 case EXT2_DIND_BLOCK:
1246 nr = i_data[EXT2_TIND_BLOCK];
1247 if (nr) {
1248 i_data[EXT2_TIND_BLOCK] = 0;
1249 mark_inode_dirty(inode);
1250 ext2_free_branches(inode, &nr, &nr+1, 3);
1251 }
1252 break;
1253 case EXT2_TIND_BLOCK:
1254 ;
1255 }
1256
1257 ext2_discard_reservation(inode);
1258
1259 mutex_unlock(&ei->truncate_mutex);
1260 }
1261
ext2_truncate_blocks(struct inode * inode,loff_t offset)1262 static void ext2_truncate_blocks(struct inode *inode, loff_t offset)
1263 {
1264 if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1265 S_ISLNK(inode->i_mode)))
1266 return;
1267 if (ext2_inode_is_fast_symlink(inode))
1268 return;
1269
1270 filemap_invalidate_lock(inode->i_mapping);
1271 __ext2_truncate_blocks(inode, offset);
1272 filemap_invalidate_unlock(inode->i_mapping);
1273 }
1274
ext2_setsize(struct inode * inode,loff_t newsize)1275 static int ext2_setsize(struct inode *inode, loff_t newsize)
1276 {
1277 int error;
1278
1279 if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1280 S_ISLNK(inode->i_mode)))
1281 return -EINVAL;
1282 if (ext2_inode_is_fast_symlink(inode))
1283 return -EINVAL;
1284 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1285 return -EPERM;
1286
1287 inode_dio_wait(inode);
1288
1289 if (IS_DAX(inode))
1290 error = dax_truncate_page(inode, newsize, NULL,
1291 &ext2_iomap_ops);
1292 else
1293 error = block_truncate_page(inode->i_mapping,
1294 newsize, ext2_get_block);
1295 if (error)
1296 return error;
1297
1298 filemap_invalidate_lock(inode->i_mapping);
1299 truncate_setsize(inode, newsize);
1300 __ext2_truncate_blocks(inode, newsize);
1301 filemap_invalidate_unlock(inode->i_mapping);
1302
1303 inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
1304 if (inode_needs_sync(inode)) {
1305 sync_mapping_buffers(inode->i_mapping);
1306 sync_inode_metadata(inode, 1);
1307 } else {
1308 mark_inode_dirty(inode);
1309 }
1310
1311 return 0;
1312 }
1313
ext2_get_inode(struct super_block * sb,ino_t ino,struct buffer_head ** p)1314 static struct ext2_inode *ext2_get_inode(struct super_block *sb, ino_t ino,
1315 struct buffer_head **p)
1316 {
1317 struct buffer_head * bh;
1318 unsigned long block_group;
1319 unsigned long block;
1320 unsigned long offset;
1321 struct ext2_group_desc * gdp;
1322
1323 *p = NULL;
1324 if ((ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) ||
1325 ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
1326 goto Einval;
1327
1328 block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
1329 gdp = ext2_get_group_desc(sb, block_group, NULL);
1330 if (!gdp)
1331 goto Egdp;
1332 /*
1333 * Figure out the offset within the block group inode table
1334 */
1335 offset = ((ino - 1) % EXT2_INODES_PER_GROUP(sb)) * EXT2_INODE_SIZE(sb);
1336 block = le32_to_cpu(gdp->bg_inode_table) +
1337 (offset >> EXT2_BLOCK_SIZE_BITS(sb));
1338 if (!(bh = sb_bread(sb, block)))
1339 goto Eio;
1340
1341 *p = bh;
1342 offset &= (EXT2_BLOCK_SIZE(sb) - 1);
1343 return (struct ext2_inode *) (bh->b_data + offset);
1344
1345 Einval:
1346 ext2_error(sb, "ext2_get_inode", "bad inode number: %lu",
1347 (unsigned long) ino);
1348 return ERR_PTR(-EINVAL);
1349 Eio:
1350 ext2_error(sb, "ext2_get_inode",
1351 "unable to read inode block - inode=%lu, block=%lu",
1352 (unsigned long) ino, block);
1353 Egdp:
1354 return ERR_PTR(-EIO);
1355 }
1356
ext2_set_inode_flags(struct inode * inode)1357 void ext2_set_inode_flags(struct inode *inode)
1358 {
1359 unsigned int flags = EXT2_I(inode)->i_flags;
1360
1361 inode->i_flags &= ~(S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME |
1362 S_DIRSYNC | S_DAX);
1363 if (flags & EXT2_SYNC_FL)
1364 inode->i_flags |= S_SYNC;
1365 if (flags & EXT2_APPEND_FL)
1366 inode->i_flags |= S_APPEND;
1367 if (flags & EXT2_IMMUTABLE_FL)
1368 inode->i_flags |= S_IMMUTABLE;
1369 if (flags & EXT2_NOATIME_FL)
1370 inode->i_flags |= S_NOATIME;
1371 if (flags & EXT2_DIRSYNC_FL)
1372 inode->i_flags |= S_DIRSYNC;
1373 if (test_opt(inode->i_sb, DAX) && S_ISREG(inode->i_mode))
1374 inode->i_flags |= S_DAX;
1375 }
1376
ext2_set_file_ops(struct inode * inode)1377 void ext2_set_file_ops(struct inode *inode)
1378 {
1379 inode->i_op = &ext2_file_inode_operations;
1380 inode->i_fop = &ext2_file_operations;
1381 if (IS_DAX(inode))
1382 inode->i_mapping->a_ops = &ext2_dax_aops;
1383 else
1384 inode->i_mapping->a_ops = &ext2_aops;
1385 }
1386
ext2_iget(struct super_block * sb,unsigned long ino)1387 struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
1388 {
1389 struct ext2_inode_info *ei;
1390 struct buffer_head * bh = NULL;
1391 struct ext2_inode *raw_inode;
1392 struct inode *inode;
1393 long ret = -EIO;
1394 int n;
1395 uid_t i_uid;
1396 gid_t i_gid;
1397
1398 inode = iget_locked(sb, ino);
1399 if (!inode)
1400 return ERR_PTR(-ENOMEM);
1401 if (!(inode->i_state & I_NEW))
1402 return inode;
1403
1404 ei = EXT2_I(inode);
1405 ei->i_block_alloc_info = NULL;
1406
1407 raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
1408 if (IS_ERR(raw_inode)) {
1409 ret = PTR_ERR(raw_inode);
1410 goto bad_inode;
1411 }
1412
1413 inode->i_mode = le16_to_cpu(raw_inode->i_mode);
1414 i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
1415 i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
1416 if (!(test_opt (inode->i_sb, NO_UID32))) {
1417 i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
1418 i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
1419 }
1420 i_uid_write(inode, i_uid);
1421 i_gid_write(inode, i_gid);
1422 set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
1423 inode->i_size = le32_to_cpu(raw_inode->i_size);
1424 inode_set_atime(inode, (signed)le32_to_cpu(raw_inode->i_atime), 0);
1425 inode_set_ctime(inode, (signed)le32_to_cpu(raw_inode->i_ctime), 0);
1426 inode_set_mtime(inode, (signed)le32_to_cpu(raw_inode->i_mtime), 0);
1427 ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
1428 /* We now have enough fields to check if the inode was active or not.
1429 * This is needed because nfsd might try to access dead inodes
1430 * the test is that same one that e2fsck uses
1431 * NeilBrown 1999oct15
1432 */
1433 if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
1434 /* this inode is deleted */
1435 ret = -ESTALE;
1436 goto bad_inode;
1437 }
1438 inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
1439 ei->i_flags = le32_to_cpu(raw_inode->i_flags);
1440 ext2_set_inode_flags(inode);
1441 ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
1442 ei->i_frag_no = raw_inode->i_frag;
1443 ei->i_frag_size = raw_inode->i_fsize;
1444 ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
1445 ei->i_dir_acl = 0;
1446
1447 if (ei->i_file_acl &&
1448 !ext2_data_block_valid(EXT2_SB(sb), ei->i_file_acl, 1)) {
1449 ext2_error(sb, "ext2_iget", "bad extended attribute block %u",
1450 ei->i_file_acl);
1451 ret = -EFSCORRUPTED;
1452 goto bad_inode;
1453 }
1454
1455 if (S_ISREG(inode->i_mode))
1456 inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
1457 else
1458 ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
1459 if (i_size_read(inode) < 0) {
1460 ret = -EFSCORRUPTED;
1461 goto bad_inode;
1462 }
1463 ei->i_dtime = 0;
1464 inode->i_generation = le32_to_cpu(raw_inode->i_generation);
1465 ei->i_state = 0;
1466 ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
1467 ei->i_dir_start_lookup = 0;
1468
1469 /*
1470 * NOTE! The in-memory inode i_data array is in little-endian order
1471 * even on big-endian machines: we do NOT byteswap the block numbers!
1472 */
1473 for (n = 0; n < EXT2_N_BLOCKS; n++)
1474 ei->i_data[n] = raw_inode->i_block[n];
1475
1476 if (S_ISREG(inode->i_mode)) {
1477 ext2_set_file_ops(inode);
1478 } else if (S_ISDIR(inode->i_mode)) {
1479 inode->i_op = &ext2_dir_inode_operations;
1480 inode->i_fop = &ext2_dir_operations;
1481 inode->i_mapping->a_ops = &ext2_aops;
1482 } else if (S_ISLNK(inode->i_mode)) {
1483 if (ext2_inode_is_fast_symlink(inode)) {
1484 inode->i_link = (char *)ei->i_data;
1485 inode->i_op = &ext2_fast_symlink_inode_operations;
1486 nd_terminate_link(ei->i_data, inode->i_size,
1487 sizeof(ei->i_data) - 1);
1488 } else {
1489 inode->i_op = &ext2_symlink_inode_operations;
1490 inode_nohighmem(inode);
1491 inode->i_mapping->a_ops = &ext2_aops;
1492 }
1493 } else {
1494 inode->i_op = &ext2_special_inode_operations;
1495 if (raw_inode->i_block[0])
1496 init_special_inode(inode, inode->i_mode,
1497 old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
1498 else
1499 init_special_inode(inode, inode->i_mode,
1500 new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
1501 }
1502 brelse (bh);
1503 unlock_new_inode(inode);
1504 return inode;
1505
1506 bad_inode:
1507 brelse(bh);
1508 iget_failed(inode);
1509 return ERR_PTR(ret);
1510 }
1511
__ext2_write_inode(struct inode * inode,int do_sync)1512 static int __ext2_write_inode(struct inode *inode, int do_sync)
1513 {
1514 struct ext2_inode_info *ei = EXT2_I(inode);
1515 struct super_block *sb = inode->i_sb;
1516 ino_t ino = inode->i_ino;
1517 uid_t uid = i_uid_read(inode);
1518 gid_t gid = i_gid_read(inode);
1519 struct buffer_head * bh;
1520 struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
1521 int n;
1522 int err = 0;
1523
1524 if (IS_ERR(raw_inode))
1525 return -EIO;
1526
1527 /* For fields not tracking in the in-memory inode,
1528 * initialise them to zero for new inodes. */
1529 if (ei->i_state & EXT2_STATE_NEW)
1530 memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size);
1531
1532 raw_inode->i_mode = cpu_to_le16(inode->i_mode);
1533 if (!(test_opt(sb, NO_UID32))) {
1534 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
1535 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(gid));
1536 /*
1537 * Fix up interoperability with old kernels. Otherwise, old inodes get
1538 * re-used with the upper 16 bits of the uid/gid intact
1539 */
1540 if (!ei->i_dtime) {
1541 raw_inode->i_uid_high = cpu_to_le16(high_16_bits(uid));
1542 raw_inode->i_gid_high = cpu_to_le16(high_16_bits(gid));
1543 } else {
1544 raw_inode->i_uid_high = 0;
1545 raw_inode->i_gid_high = 0;
1546 }
1547 } else {
1548 raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(uid));
1549 raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid));
1550 raw_inode->i_uid_high = 0;
1551 raw_inode->i_gid_high = 0;
1552 }
1553 raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
1554 raw_inode->i_size = cpu_to_le32(inode->i_size);
1555 raw_inode->i_atime = cpu_to_le32(inode_get_atime_sec(inode));
1556 raw_inode->i_ctime = cpu_to_le32(inode_get_ctime_sec(inode));
1557 raw_inode->i_mtime = cpu_to_le32(inode_get_mtime_sec(inode));
1558
1559 raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
1560 raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
1561 raw_inode->i_flags = cpu_to_le32(ei->i_flags);
1562 raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
1563 raw_inode->i_frag = ei->i_frag_no;
1564 raw_inode->i_fsize = ei->i_frag_size;
1565 raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
1566 if (!S_ISREG(inode->i_mode))
1567 raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
1568 else {
1569 raw_inode->i_size_high = cpu_to_le32(inode->i_size >> 32);
1570 if (inode->i_size > 0x7fffffffULL) {
1571 if (!EXT2_HAS_RO_COMPAT_FEATURE(sb,
1572 EXT2_FEATURE_RO_COMPAT_LARGE_FILE) ||
1573 EXT2_SB(sb)->s_es->s_rev_level ==
1574 cpu_to_le32(EXT2_GOOD_OLD_REV)) {
1575 /* If this is the first large file
1576 * created, add a flag to the superblock.
1577 */
1578 spin_lock(&EXT2_SB(sb)->s_lock);
1579 ext2_update_dynamic_rev(sb);
1580 EXT2_SET_RO_COMPAT_FEATURE(sb,
1581 EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
1582 spin_unlock(&EXT2_SB(sb)->s_lock);
1583 ext2_sync_super(sb, EXT2_SB(sb)->s_es, 1);
1584 }
1585 }
1586 }
1587
1588 raw_inode->i_generation = cpu_to_le32(inode->i_generation);
1589 if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
1590 if (old_valid_dev(inode->i_rdev)) {
1591 raw_inode->i_block[0] =
1592 cpu_to_le32(old_encode_dev(inode->i_rdev));
1593 raw_inode->i_block[1] = 0;
1594 } else {
1595 raw_inode->i_block[0] = 0;
1596 raw_inode->i_block[1] =
1597 cpu_to_le32(new_encode_dev(inode->i_rdev));
1598 raw_inode->i_block[2] = 0;
1599 }
1600 } else for (n = 0; n < EXT2_N_BLOCKS; n++)
1601 raw_inode->i_block[n] = ei->i_data[n];
1602 mark_buffer_dirty(bh);
1603 if (do_sync) {
1604 sync_dirty_buffer(bh);
1605 if (buffer_req(bh) && !buffer_uptodate(bh)) {
1606 printk ("IO error syncing ext2 inode [%s:%08lx]\n",
1607 sb->s_id, (unsigned long) ino);
1608 err = -EIO;
1609 }
1610 }
1611 ei->i_state &= ~EXT2_STATE_NEW;
1612 brelse (bh);
1613 return err;
1614 }
1615
ext2_write_inode(struct inode * inode,struct writeback_control * wbc)1616 int ext2_write_inode(struct inode *inode, struct writeback_control *wbc)
1617 {
1618 return __ext2_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
1619 }
1620
ext2_getattr(struct mnt_idmap * idmap,const struct path * path,struct kstat * stat,u32 request_mask,unsigned int query_flags)1621 int ext2_getattr(struct mnt_idmap *idmap, const struct path *path,
1622 struct kstat *stat, u32 request_mask, unsigned int query_flags)
1623 {
1624 struct inode *inode = d_inode(path->dentry);
1625 struct ext2_inode_info *ei = EXT2_I(inode);
1626 unsigned int flags;
1627
1628 flags = ei->i_flags & EXT2_FL_USER_VISIBLE;
1629 if (flags & EXT2_APPEND_FL)
1630 stat->attributes |= STATX_ATTR_APPEND;
1631 if (flags & EXT2_COMPR_FL)
1632 stat->attributes |= STATX_ATTR_COMPRESSED;
1633 if (flags & EXT2_IMMUTABLE_FL)
1634 stat->attributes |= STATX_ATTR_IMMUTABLE;
1635 if (flags & EXT2_NODUMP_FL)
1636 stat->attributes |= STATX_ATTR_NODUMP;
1637 stat->attributes_mask |= (STATX_ATTR_APPEND |
1638 STATX_ATTR_COMPRESSED |
1639 STATX_ATTR_ENCRYPTED |
1640 STATX_ATTR_IMMUTABLE |
1641 STATX_ATTR_NODUMP);
1642
1643 generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
1644 return 0;
1645 }
1646
ext2_setattr(struct mnt_idmap * idmap,struct dentry * dentry,struct iattr * iattr)1647 int ext2_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
1648 struct iattr *iattr)
1649 {
1650 struct inode *inode = d_inode(dentry);
1651 int error;
1652
1653 error = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
1654 if (error)
1655 return error;
1656
1657 if (is_quota_modification(&nop_mnt_idmap, inode, iattr)) {
1658 error = dquot_initialize(inode);
1659 if (error)
1660 return error;
1661 }
1662 if (i_uid_needs_update(&nop_mnt_idmap, iattr, inode) ||
1663 i_gid_needs_update(&nop_mnt_idmap, iattr, inode)) {
1664 error = dquot_transfer(&nop_mnt_idmap, inode, iattr);
1665 if (error)
1666 return error;
1667 }
1668 if (iattr->ia_valid & ATTR_SIZE && iattr->ia_size != inode->i_size) {
1669 error = ext2_setsize(inode, iattr->ia_size);
1670 if (error)
1671 return error;
1672 }
1673 setattr_copy(&nop_mnt_idmap, inode, iattr);
1674 if (iattr->ia_valid & ATTR_MODE)
1675 error = posix_acl_chmod(&nop_mnt_idmap, dentry, inode->i_mode);
1676 mark_inode_dirty(inode);
1677
1678 return error;
1679 }
1680