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_NOFS);
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
899 inode_lock(inode);
900 len = min_t(u64, len, i_size_read(inode));
901 ret = iomap_fiemap(inode, fieinfo, start, len, &ext2_iomap_ops);
902 inode_unlock(inode);
903
904 return ret;
905 }
906
ext2_read_folio(struct file * file,struct folio * folio)907 static int ext2_read_folio(struct file *file, struct folio *folio)
908 {
909 return mpage_read_folio(folio, ext2_get_block);
910 }
911
ext2_readahead(struct readahead_control * rac)912 static void ext2_readahead(struct readahead_control *rac)
913 {
914 mpage_readahead(rac, ext2_get_block);
915 }
916
917 static int
ext2_write_begin(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,struct page ** pagep,void ** fsdata)918 ext2_write_begin(struct file *file, struct address_space *mapping,
919 loff_t pos, unsigned len, struct page **pagep, void **fsdata)
920 {
921 int ret;
922
923 ret = block_write_begin(mapping, pos, len, pagep, ext2_get_block);
924 if (ret < 0)
925 ext2_write_failed(mapping, pos + len);
926 return ret;
927 }
928
ext2_write_end(struct file * file,struct address_space * mapping,loff_t pos,unsigned len,unsigned copied,struct page * page,void * fsdata)929 static int ext2_write_end(struct file *file, struct address_space *mapping,
930 loff_t pos, unsigned len, unsigned copied,
931 struct page *page, void *fsdata)
932 {
933 int ret;
934
935 ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
936 if (ret < len)
937 ext2_write_failed(mapping, pos + len);
938 return ret;
939 }
940
ext2_bmap(struct address_space * mapping,sector_t block)941 static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
942 {
943 return generic_block_bmap(mapping,block,ext2_get_block);
944 }
945
946 static int
ext2_writepages(struct address_space * mapping,struct writeback_control * wbc)947 ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
948 {
949 return mpage_writepages(mapping, wbc, ext2_get_block);
950 }
951
952 static int
ext2_dax_writepages(struct address_space * mapping,struct writeback_control * wbc)953 ext2_dax_writepages(struct address_space *mapping, struct writeback_control *wbc)
954 {
955 struct ext2_sb_info *sbi = EXT2_SB(mapping->host->i_sb);
956
957 return dax_writeback_mapping_range(mapping, sbi->s_daxdev, wbc);
958 }
959
960 const struct address_space_operations ext2_aops = {
961 .dirty_folio = block_dirty_folio,
962 .invalidate_folio = block_invalidate_folio,
963 .read_folio = ext2_read_folio,
964 .readahead = ext2_readahead,
965 .write_begin = ext2_write_begin,
966 .write_end = ext2_write_end,
967 .bmap = ext2_bmap,
968 .direct_IO = noop_direct_IO,
969 .writepages = ext2_writepages,
970 .migrate_folio = buffer_migrate_folio,
971 .is_partially_uptodate = block_is_partially_uptodate,
972 .error_remove_page = generic_error_remove_page,
973 };
974
975 static const struct address_space_operations ext2_dax_aops = {
976 .writepages = ext2_dax_writepages,
977 .direct_IO = noop_direct_IO,
978 .dirty_folio = noop_dirty_folio,
979 };
980
981 /*
982 * Probably it should be a library function... search for first non-zero word
983 * or memcmp with zero_page, whatever is better for particular architecture.
984 * Linus?
985 */
all_zeroes(__le32 * p,__le32 * q)986 static inline int all_zeroes(__le32 *p, __le32 *q)
987 {
988 while (p < q)
989 if (*p++)
990 return 0;
991 return 1;
992 }
993
994 /**
995 * ext2_find_shared - find the indirect blocks for partial truncation.
996 * @inode: inode in question
997 * @depth: depth of the affected branch
998 * @offsets: offsets of pointers in that branch (see ext2_block_to_path)
999 * @chain: place to store the pointers to partial indirect blocks
1000 * @top: place to the (detached) top of branch
1001 *
1002 * This is a helper function used by ext2_truncate().
1003 *
1004 * When we do truncate() we may have to clean the ends of several indirect
1005 * blocks but leave the blocks themselves alive. Block is partially
1006 * truncated if some data below the new i_size is referred from it (and
1007 * it is on the path to the first completely truncated data block, indeed).
1008 * We have to free the top of that path along with everything to the right
1009 * of the path. Since no allocation past the truncation point is possible
1010 * until ext2_truncate() finishes, we may safely do the latter, but top
1011 * of branch may require special attention - pageout below the truncation
1012 * point might try to populate it.
1013 *
1014 * We atomically detach the top of branch from the tree, store the block
1015 * number of its root in *@top, pointers to buffer_heads of partially
1016 * truncated blocks - in @chain[].bh and pointers to their last elements
1017 * that should not be removed - in @chain[].p. Return value is the pointer
1018 * to last filled element of @chain.
1019 *
1020 * The work left to caller to do the actual freeing of subtrees:
1021 * a) free the subtree starting from *@top
1022 * b) free the subtrees whose roots are stored in
1023 * (@chain[i].p+1 .. end of @chain[i].bh->b_data)
1024 * c) free the subtrees growing from the inode past the @chain[0].p
1025 * (no partially truncated stuff there).
1026 */
1027
ext2_find_shared(struct inode * inode,int depth,int offsets[4],Indirect chain[4],__le32 * top)1028 static Indirect *ext2_find_shared(struct inode *inode,
1029 int depth,
1030 int offsets[4],
1031 Indirect chain[4],
1032 __le32 *top)
1033 {
1034 Indirect *partial, *p;
1035 int k, err;
1036
1037 *top = 0;
1038 for (k = depth; k > 1 && !offsets[k-1]; k--)
1039 ;
1040 partial = ext2_get_branch(inode, k, offsets, chain, &err);
1041 if (!partial)
1042 partial = chain + k-1;
1043 /*
1044 * If the branch acquired continuation since we've looked at it -
1045 * fine, it should all survive and (new) top doesn't belong to us.
1046 */
1047 write_lock(&EXT2_I(inode)->i_meta_lock);
1048 if (!partial->key && *partial->p) {
1049 write_unlock(&EXT2_I(inode)->i_meta_lock);
1050 goto no_top;
1051 }
1052 for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
1053 ;
1054 /*
1055 * OK, we've found the last block that must survive. The rest of our
1056 * branch should be detached before unlocking. However, if that rest
1057 * of branch is all ours and does not grow immediately from the inode
1058 * it's easier to cheat and just decrement partial->p.
1059 */
1060 if (p == chain + k - 1 && p > chain) {
1061 p->p--;
1062 } else {
1063 *top = *p->p;
1064 *p->p = 0;
1065 }
1066 write_unlock(&EXT2_I(inode)->i_meta_lock);
1067
1068 while(partial > p)
1069 {
1070 brelse(partial->bh);
1071 partial--;
1072 }
1073 no_top:
1074 return partial;
1075 }
1076
1077 /**
1078 * ext2_free_data - free a list of data blocks
1079 * @inode: inode we are dealing with
1080 * @p: array of block numbers
1081 * @q: points immediately past the end of array
1082 *
1083 * We are freeing all blocks referred from that array (numbers are
1084 * stored as little-endian 32-bit) and updating @inode->i_blocks
1085 * appropriately.
1086 */
ext2_free_data(struct inode * inode,__le32 * p,__le32 * q)1087 static inline void ext2_free_data(struct inode *inode, __le32 *p, __le32 *q)
1088 {
1089 ext2_fsblk_t block_to_free = 0, count = 0;
1090 ext2_fsblk_t nr;
1091
1092 for ( ; p < q ; p++) {
1093 nr = le32_to_cpu(*p);
1094 if (nr) {
1095 *p = 0;
1096 /* accumulate blocks to free if they're contiguous */
1097 if (count == 0)
1098 goto free_this;
1099 else if (block_to_free == nr - count)
1100 count++;
1101 else {
1102 ext2_free_blocks (inode, block_to_free, count);
1103 mark_inode_dirty(inode);
1104 free_this:
1105 block_to_free = nr;
1106 count = 1;
1107 }
1108 }
1109 }
1110 if (count > 0) {
1111 ext2_free_blocks (inode, block_to_free, count);
1112 mark_inode_dirty(inode);
1113 }
1114 }
1115
1116 /**
1117 * ext2_free_branches - free an array of branches
1118 * @inode: inode we are dealing with
1119 * @p: array of block numbers
1120 * @q: pointer immediately past the end of array
1121 * @depth: depth of the branches to free
1122 *
1123 * We are freeing all blocks referred from these branches (numbers are
1124 * stored as little-endian 32-bit) and updating @inode->i_blocks
1125 * appropriately.
1126 */
ext2_free_branches(struct inode * inode,__le32 * p,__le32 * q,int depth)1127 static void ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int depth)
1128 {
1129 struct buffer_head * bh;
1130 ext2_fsblk_t nr;
1131
1132 if (depth--) {
1133 int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1134 for ( ; p < q ; p++) {
1135 nr = le32_to_cpu(*p);
1136 if (!nr)
1137 continue;
1138 *p = 0;
1139 bh = sb_bread(inode->i_sb, nr);
1140 /*
1141 * A read failure? Report error and clear slot
1142 * (should be rare).
1143 */
1144 if (!bh) {
1145 ext2_error(inode->i_sb, "ext2_free_branches",
1146 "Read failure, inode=%ld, block=%ld",
1147 inode->i_ino, nr);
1148 continue;
1149 }
1150 ext2_free_branches(inode,
1151 (__le32*)bh->b_data,
1152 (__le32*)bh->b_data + addr_per_block,
1153 depth);
1154 bforget(bh);
1155 ext2_free_blocks(inode, nr, 1);
1156 mark_inode_dirty(inode);
1157 }
1158 } else
1159 ext2_free_data(inode, p, q);
1160 }
1161
1162 /* mapping->invalidate_lock must be held when calling this function */
__ext2_truncate_blocks(struct inode * inode,loff_t offset)1163 static void __ext2_truncate_blocks(struct inode *inode, loff_t offset)
1164 {
1165 __le32 *i_data = EXT2_I(inode)->i_data;
1166 struct ext2_inode_info *ei = EXT2_I(inode);
1167 int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1168 int offsets[4];
1169 Indirect chain[4];
1170 Indirect *partial;
1171 __le32 nr = 0;
1172 int n;
1173 long iblock;
1174 unsigned blocksize;
1175 blocksize = inode->i_sb->s_blocksize;
1176 iblock = (offset + blocksize-1) >> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
1177
1178 #ifdef CONFIG_FS_DAX
1179 WARN_ON(!rwsem_is_locked(&inode->i_mapping->invalidate_lock));
1180 #endif
1181
1182 n = ext2_block_to_path(inode, iblock, offsets, NULL);
1183 if (n == 0)
1184 return;
1185
1186 /*
1187 * From here we block out all ext2_get_block() callers who want to
1188 * modify the block allocation tree.
1189 */
1190 mutex_lock(&ei->truncate_mutex);
1191
1192 if (n == 1) {
1193 ext2_free_data(inode, i_data+offsets[0],
1194 i_data + EXT2_NDIR_BLOCKS);
1195 goto do_indirects;
1196 }
1197
1198 partial = ext2_find_shared(inode, n, offsets, chain, &nr);
1199 /* Kill the top of shared branch (already detached) */
1200 if (nr) {
1201 if (partial == chain)
1202 mark_inode_dirty(inode);
1203 else
1204 mark_buffer_dirty_inode(partial->bh, inode);
1205 ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
1206 }
1207 /* Clear the ends of indirect blocks on the shared branch */
1208 while (partial > chain) {
1209 ext2_free_branches(inode,
1210 partial->p + 1,
1211 (__le32*)partial->bh->b_data+addr_per_block,
1212 (chain+n-1) - partial);
1213 mark_buffer_dirty_inode(partial->bh, inode);
1214 brelse (partial->bh);
1215 partial--;
1216 }
1217 do_indirects:
1218 /* Kill the remaining (whole) subtrees */
1219 switch (offsets[0]) {
1220 default:
1221 nr = i_data[EXT2_IND_BLOCK];
1222 if (nr) {
1223 i_data[EXT2_IND_BLOCK] = 0;
1224 mark_inode_dirty(inode);
1225 ext2_free_branches(inode, &nr, &nr+1, 1);
1226 }
1227 fallthrough;
1228 case EXT2_IND_BLOCK:
1229 nr = i_data[EXT2_DIND_BLOCK];
1230 if (nr) {
1231 i_data[EXT2_DIND_BLOCK] = 0;
1232 mark_inode_dirty(inode);
1233 ext2_free_branches(inode, &nr, &nr+1, 2);
1234 }
1235 fallthrough;
1236 case EXT2_DIND_BLOCK:
1237 nr = i_data[EXT2_TIND_BLOCK];
1238 if (nr) {
1239 i_data[EXT2_TIND_BLOCK] = 0;
1240 mark_inode_dirty(inode);
1241 ext2_free_branches(inode, &nr, &nr+1, 3);
1242 }
1243 break;
1244 case EXT2_TIND_BLOCK:
1245 ;
1246 }
1247
1248 ext2_discard_reservation(inode);
1249
1250 mutex_unlock(&ei->truncate_mutex);
1251 }
1252
ext2_truncate_blocks(struct inode * inode,loff_t offset)1253 static void ext2_truncate_blocks(struct inode *inode, loff_t offset)
1254 {
1255 if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1256 S_ISLNK(inode->i_mode)))
1257 return;
1258 if (ext2_inode_is_fast_symlink(inode))
1259 return;
1260
1261 filemap_invalidate_lock(inode->i_mapping);
1262 __ext2_truncate_blocks(inode, offset);
1263 filemap_invalidate_unlock(inode->i_mapping);
1264 }
1265
ext2_setsize(struct inode * inode,loff_t newsize)1266 static int ext2_setsize(struct inode *inode, loff_t newsize)
1267 {
1268 int error;
1269
1270 if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1271 S_ISLNK(inode->i_mode)))
1272 return -EINVAL;
1273 if (ext2_inode_is_fast_symlink(inode))
1274 return -EINVAL;
1275 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1276 return -EPERM;
1277
1278 inode_dio_wait(inode);
1279
1280 if (IS_DAX(inode))
1281 error = dax_truncate_page(inode, newsize, NULL,
1282 &ext2_iomap_ops);
1283 else
1284 error = block_truncate_page(inode->i_mapping,
1285 newsize, ext2_get_block);
1286 if (error)
1287 return error;
1288
1289 filemap_invalidate_lock(inode->i_mapping);
1290 truncate_setsize(inode, newsize);
1291 __ext2_truncate_blocks(inode, newsize);
1292 filemap_invalidate_unlock(inode->i_mapping);
1293
1294 inode->i_mtime = inode_set_ctime_current(inode);
1295 if (inode_needs_sync(inode)) {
1296 sync_mapping_buffers(inode->i_mapping);
1297 sync_inode_metadata(inode, 1);
1298 } else {
1299 mark_inode_dirty(inode);
1300 }
1301
1302 return 0;
1303 }
1304
ext2_get_inode(struct super_block * sb,ino_t ino,struct buffer_head ** p)1305 static struct ext2_inode *ext2_get_inode(struct super_block *sb, ino_t ino,
1306 struct buffer_head **p)
1307 {
1308 struct buffer_head * bh;
1309 unsigned long block_group;
1310 unsigned long block;
1311 unsigned long offset;
1312 struct ext2_group_desc * gdp;
1313
1314 *p = NULL;
1315 if ((ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) ||
1316 ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
1317 goto Einval;
1318
1319 block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
1320 gdp = ext2_get_group_desc(sb, block_group, NULL);
1321 if (!gdp)
1322 goto Egdp;
1323 /*
1324 * Figure out the offset within the block group inode table
1325 */
1326 offset = ((ino - 1) % EXT2_INODES_PER_GROUP(sb)) * EXT2_INODE_SIZE(sb);
1327 block = le32_to_cpu(gdp->bg_inode_table) +
1328 (offset >> EXT2_BLOCK_SIZE_BITS(sb));
1329 if (!(bh = sb_bread(sb, block)))
1330 goto Eio;
1331
1332 *p = bh;
1333 offset &= (EXT2_BLOCK_SIZE(sb) - 1);
1334 return (struct ext2_inode *) (bh->b_data + offset);
1335
1336 Einval:
1337 ext2_error(sb, "ext2_get_inode", "bad inode number: %lu",
1338 (unsigned long) ino);
1339 return ERR_PTR(-EINVAL);
1340 Eio:
1341 ext2_error(sb, "ext2_get_inode",
1342 "unable to read inode block - inode=%lu, block=%lu",
1343 (unsigned long) ino, block);
1344 Egdp:
1345 return ERR_PTR(-EIO);
1346 }
1347
ext2_set_inode_flags(struct inode * inode)1348 void ext2_set_inode_flags(struct inode *inode)
1349 {
1350 unsigned int flags = EXT2_I(inode)->i_flags;
1351
1352 inode->i_flags &= ~(S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME |
1353 S_DIRSYNC | S_DAX);
1354 if (flags & EXT2_SYNC_FL)
1355 inode->i_flags |= S_SYNC;
1356 if (flags & EXT2_APPEND_FL)
1357 inode->i_flags |= S_APPEND;
1358 if (flags & EXT2_IMMUTABLE_FL)
1359 inode->i_flags |= S_IMMUTABLE;
1360 if (flags & EXT2_NOATIME_FL)
1361 inode->i_flags |= S_NOATIME;
1362 if (flags & EXT2_DIRSYNC_FL)
1363 inode->i_flags |= S_DIRSYNC;
1364 if (test_opt(inode->i_sb, DAX) && S_ISREG(inode->i_mode))
1365 inode->i_flags |= S_DAX;
1366 }
1367
ext2_set_file_ops(struct inode * inode)1368 void ext2_set_file_ops(struct inode *inode)
1369 {
1370 inode->i_op = &ext2_file_inode_operations;
1371 inode->i_fop = &ext2_file_operations;
1372 if (IS_DAX(inode))
1373 inode->i_mapping->a_ops = &ext2_dax_aops;
1374 else
1375 inode->i_mapping->a_ops = &ext2_aops;
1376 }
1377
ext2_iget(struct super_block * sb,unsigned long ino)1378 struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
1379 {
1380 struct ext2_inode_info *ei;
1381 struct buffer_head * bh = NULL;
1382 struct ext2_inode *raw_inode;
1383 struct inode *inode;
1384 long ret = -EIO;
1385 int n;
1386 uid_t i_uid;
1387 gid_t i_gid;
1388
1389 inode = iget_locked(sb, ino);
1390 if (!inode)
1391 return ERR_PTR(-ENOMEM);
1392 if (!(inode->i_state & I_NEW))
1393 return inode;
1394
1395 ei = EXT2_I(inode);
1396 ei->i_block_alloc_info = NULL;
1397
1398 raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
1399 if (IS_ERR(raw_inode)) {
1400 ret = PTR_ERR(raw_inode);
1401 goto bad_inode;
1402 }
1403
1404 inode->i_mode = le16_to_cpu(raw_inode->i_mode);
1405 i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
1406 i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
1407 if (!(test_opt (inode->i_sb, NO_UID32))) {
1408 i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
1409 i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
1410 }
1411 i_uid_write(inode, i_uid);
1412 i_gid_write(inode, i_gid);
1413 set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
1414 inode->i_size = le32_to_cpu(raw_inode->i_size);
1415 inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
1416 inode_set_ctime(inode, (signed)le32_to_cpu(raw_inode->i_ctime), 0);
1417 inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
1418 inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = 0;
1419 ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
1420 /* We now have enough fields to check if the inode was active or not.
1421 * This is needed because nfsd might try to access dead inodes
1422 * the test is that same one that e2fsck uses
1423 * NeilBrown 1999oct15
1424 */
1425 if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
1426 /* this inode is deleted */
1427 ret = -ESTALE;
1428 goto bad_inode;
1429 }
1430 inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
1431 ei->i_flags = le32_to_cpu(raw_inode->i_flags);
1432 ext2_set_inode_flags(inode);
1433 ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
1434 ei->i_frag_no = raw_inode->i_frag;
1435 ei->i_frag_size = raw_inode->i_fsize;
1436 ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
1437 ei->i_dir_acl = 0;
1438
1439 if (ei->i_file_acl &&
1440 !ext2_data_block_valid(EXT2_SB(sb), ei->i_file_acl, 1)) {
1441 ext2_error(sb, "ext2_iget", "bad extended attribute block %u",
1442 ei->i_file_acl);
1443 ret = -EFSCORRUPTED;
1444 goto bad_inode;
1445 }
1446
1447 if (S_ISREG(inode->i_mode))
1448 inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
1449 else
1450 ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
1451 if (i_size_read(inode) < 0) {
1452 ret = -EFSCORRUPTED;
1453 goto bad_inode;
1454 }
1455 ei->i_dtime = 0;
1456 inode->i_generation = le32_to_cpu(raw_inode->i_generation);
1457 ei->i_state = 0;
1458 ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
1459 ei->i_dir_start_lookup = 0;
1460
1461 /*
1462 * NOTE! The in-memory inode i_data array is in little-endian order
1463 * even on big-endian machines: we do NOT byteswap the block numbers!
1464 */
1465 for (n = 0; n < EXT2_N_BLOCKS; n++)
1466 ei->i_data[n] = raw_inode->i_block[n];
1467
1468 if (S_ISREG(inode->i_mode)) {
1469 ext2_set_file_ops(inode);
1470 } else if (S_ISDIR(inode->i_mode)) {
1471 inode->i_op = &ext2_dir_inode_operations;
1472 inode->i_fop = &ext2_dir_operations;
1473 inode->i_mapping->a_ops = &ext2_aops;
1474 } else if (S_ISLNK(inode->i_mode)) {
1475 if (ext2_inode_is_fast_symlink(inode)) {
1476 inode->i_link = (char *)ei->i_data;
1477 inode->i_op = &ext2_fast_symlink_inode_operations;
1478 nd_terminate_link(ei->i_data, inode->i_size,
1479 sizeof(ei->i_data) - 1);
1480 } else {
1481 inode->i_op = &ext2_symlink_inode_operations;
1482 inode_nohighmem(inode);
1483 inode->i_mapping->a_ops = &ext2_aops;
1484 }
1485 } else {
1486 inode->i_op = &ext2_special_inode_operations;
1487 if (raw_inode->i_block[0])
1488 init_special_inode(inode, inode->i_mode,
1489 old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
1490 else
1491 init_special_inode(inode, inode->i_mode,
1492 new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
1493 }
1494 brelse (bh);
1495 unlock_new_inode(inode);
1496 return inode;
1497
1498 bad_inode:
1499 brelse(bh);
1500 iget_failed(inode);
1501 return ERR_PTR(ret);
1502 }
1503
__ext2_write_inode(struct inode * inode,int do_sync)1504 static int __ext2_write_inode(struct inode *inode, int do_sync)
1505 {
1506 struct ext2_inode_info *ei = EXT2_I(inode);
1507 struct super_block *sb = inode->i_sb;
1508 ino_t ino = inode->i_ino;
1509 uid_t uid = i_uid_read(inode);
1510 gid_t gid = i_gid_read(inode);
1511 struct buffer_head * bh;
1512 struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
1513 int n;
1514 int err = 0;
1515
1516 if (IS_ERR(raw_inode))
1517 return -EIO;
1518
1519 /* For fields not tracking in the in-memory inode,
1520 * initialise them to zero for new inodes. */
1521 if (ei->i_state & EXT2_STATE_NEW)
1522 memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size);
1523
1524 raw_inode->i_mode = cpu_to_le16(inode->i_mode);
1525 if (!(test_opt(sb, NO_UID32))) {
1526 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
1527 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(gid));
1528 /*
1529 * Fix up interoperability with old kernels. Otherwise, old inodes get
1530 * re-used with the upper 16 bits of the uid/gid intact
1531 */
1532 if (!ei->i_dtime) {
1533 raw_inode->i_uid_high = cpu_to_le16(high_16_bits(uid));
1534 raw_inode->i_gid_high = cpu_to_le16(high_16_bits(gid));
1535 } else {
1536 raw_inode->i_uid_high = 0;
1537 raw_inode->i_gid_high = 0;
1538 }
1539 } else {
1540 raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(uid));
1541 raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid));
1542 raw_inode->i_uid_high = 0;
1543 raw_inode->i_gid_high = 0;
1544 }
1545 raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
1546 raw_inode->i_size = cpu_to_le32(inode->i_size);
1547 raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
1548 raw_inode->i_ctime = cpu_to_le32(inode_get_ctime(inode).tv_sec);
1549 raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
1550
1551 raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
1552 raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
1553 raw_inode->i_flags = cpu_to_le32(ei->i_flags);
1554 raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
1555 raw_inode->i_frag = ei->i_frag_no;
1556 raw_inode->i_fsize = ei->i_frag_size;
1557 raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
1558 if (!S_ISREG(inode->i_mode))
1559 raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
1560 else {
1561 raw_inode->i_size_high = cpu_to_le32(inode->i_size >> 32);
1562 if (inode->i_size > 0x7fffffffULL) {
1563 if (!EXT2_HAS_RO_COMPAT_FEATURE(sb,
1564 EXT2_FEATURE_RO_COMPAT_LARGE_FILE) ||
1565 EXT2_SB(sb)->s_es->s_rev_level ==
1566 cpu_to_le32(EXT2_GOOD_OLD_REV)) {
1567 /* If this is the first large file
1568 * created, add a flag to the superblock.
1569 */
1570 spin_lock(&EXT2_SB(sb)->s_lock);
1571 ext2_update_dynamic_rev(sb);
1572 EXT2_SET_RO_COMPAT_FEATURE(sb,
1573 EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
1574 spin_unlock(&EXT2_SB(sb)->s_lock);
1575 ext2_sync_super(sb, EXT2_SB(sb)->s_es, 1);
1576 }
1577 }
1578 }
1579
1580 raw_inode->i_generation = cpu_to_le32(inode->i_generation);
1581 if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
1582 if (old_valid_dev(inode->i_rdev)) {
1583 raw_inode->i_block[0] =
1584 cpu_to_le32(old_encode_dev(inode->i_rdev));
1585 raw_inode->i_block[1] = 0;
1586 } else {
1587 raw_inode->i_block[0] = 0;
1588 raw_inode->i_block[1] =
1589 cpu_to_le32(new_encode_dev(inode->i_rdev));
1590 raw_inode->i_block[2] = 0;
1591 }
1592 } else for (n = 0; n < EXT2_N_BLOCKS; n++)
1593 raw_inode->i_block[n] = ei->i_data[n];
1594 mark_buffer_dirty(bh);
1595 if (do_sync) {
1596 sync_dirty_buffer(bh);
1597 if (buffer_req(bh) && !buffer_uptodate(bh)) {
1598 printk ("IO error syncing ext2 inode [%s:%08lx]\n",
1599 sb->s_id, (unsigned long) ino);
1600 err = -EIO;
1601 }
1602 }
1603 ei->i_state &= ~EXT2_STATE_NEW;
1604 brelse (bh);
1605 return err;
1606 }
1607
ext2_write_inode(struct inode * inode,struct writeback_control * wbc)1608 int ext2_write_inode(struct inode *inode, struct writeback_control *wbc)
1609 {
1610 return __ext2_write_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
1611 }
1612
ext2_getattr(struct mnt_idmap * idmap,const struct path * path,struct kstat * stat,u32 request_mask,unsigned int query_flags)1613 int ext2_getattr(struct mnt_idmap *idmap, const struct path *path,
1614 struct kstat *stat, u32 request_mask, unsigned int query_flags)
1615 {
1616 struct inode *inode = d_inode(path->dentry);
1617 struct ext2_inode_info *ei = EXT2_I(inode);
1618 unsigned int flags;
1619
1620 flags = ei->i_flags & EXT2_FL_USER_VISIBLE;
1621 if (flags & EXT2_APPEND_FL)
1622 stat->attributes |= STATX_ATTR_APPEND;
1623 if (flags & EXT2_COMPR_FL)
1624 stat->attributes |= STATX_ATTR_COMPRESSED;
1625 if (flags & EXT2_IMMUTABLE_FL)
1626 stat->attributes |= STATX_ATTR_IMMUTABLE;
1627 if (flags & EXT2_NODUMP_FL)
1628 stat->attributes |= STATX_ATTR_NODUMP;
1629 stat->attributes_mask |= (STATX_ATTR_APPEND |
1630 STATX_ATTR_COMPRESSED |
1631 STATX_ATTR_ENCRYPTED |
1632 STATX_ATTR_IMMUTABLE |
1633 STATX_ATTR_NODUMP);
1634
1635 generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
1636 return 0;
1637 }
1638
ext2_setattr(struct mnt_idmap * idmap,struct dentry * dentry,struct iattr * iattr)1639 int ext2_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
1640 struct iattr *iattr)
1641 {
1642 struct inode *inode = d_inode(dentry);
1643 int error;
1644
1645 error = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
1646 if (error)
1647 return error;
1648
1649 if (is_quota_modification(&nop_mnt_idmap, inode, iattr)) {
1650 error = dquot_initialize(inode);
1651 if (error)
1652 return error;
1653 }
1654 if (i_uid_needs_update(&nop_mnt_idmap, iattr, inode) ||
1655 i_gid_needs_update(&nop_mnt_idmap, iattr, inode)) {
1656 error = dquot_transfer(&nop_mnt_idmap, inode, iattr);
1657 if (error)
1658 return error;
1659 }
1660 if (iattr->ia_valid & ATTR_SIZE && iattr->ia_size != inode->i_size) {
1661 error = ext2_setsize(inode, iattr->ia_size);
1662 if (error)
1663 return error;
1664 }
1665 setattr_copy(&nop_mnt_idmap, inode, iattr);
1666 if (iattr->ia_valid & ATTR_MODE)
1667 error = posix_acl_chmod(&nop_mnt_idmap, dentry, inode->i_mode);
1668 mark_inode_dirty(inode);
1669
1670 return error;
1671 }
1672