blob: 991d6dfeb51f078bfe746e6dede400e7e2525817 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/ext2/inode.c
3 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 *
9 * from
10 *
11 * linux/fs/minix/inode.c
12 *
13 * Copyright (C) 1991, 1992 Linus Torvalds
14 *
15 * Goal-directed block allocation by Stephen Tweedie
16 * (sct@dcs.ed.ac.uk), 1993, 1998
17 * Big-endian to little-endian byte-swapping/bitmaps by
18 * David S. Miller (davem@caip.rutgers.edu), 1995
19 * 64-bit file support on 64-bit platforms by Jakub Jelinek
20 * (jj@sunsite.ms.mff.cuni.cz)
21 *
22 * Assorted race fixes, rewrite of ext2_get_block() by Al Viro, 2000
23 */
24
25#include <linux/smp_lock.h>
26#include <linux/time.h>
27#include <linux/highuid.h>
28#include <linux/pagemap.h>
29#include <linux/quotaops.h>
30#include <linux/module.h>
31#include <linux/writeback.h>
32#include <linux/buffer_head.h>
33#include <linux/mpage.h>
34#include "ext2.h"
35#include "acl.h"
Carsten Otte6d791252005-06-23 22:05:26 -070036#include "xip.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
38MODULE_AUTHOR("Remy Card and others");
39MODULE_DESCRIPTION("Second Extended Filesystem");
40MODULE_LICENSE("GPL");
41
42static int ext2_update_inode(struct inode * inode, int do_sync);
43
44/*
45 * Test whether an inode is a fast symlink.
46 */
47static inline int ext2_inode_is_fast_symlink(struct inode *inode)
48{
49 int ea_blocks = EXT2_I(inode)->i_file_acl ?
50 (inode->i_sb->s_blocksize >> 9) : 0;
51
52 return (S_ISLNK(inode->i_mode) &&
53 inode->i_blocks - ea_blocks == 0);
54}
55
56/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070057 * Called at the last iput() if i_nlink is zero.
58 */
59void ext2_delete_inode (struct inode * inode)
60{
Mark Fashehfef26652005-09-09 13:01:31 -070061 truncate_inode_pages(&inode->i_data, 0);
62
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 if (is_bad_inode(inode))
64 goto no_delete;
65 EXT2_I(inode)->i_dtime = get_seconds();
66 mark_inode_dirty(inode);
67 ext2_update_inode(inode, inode_needs_sync(inode));
68
69 inode->i_size = 0;
70 if (inode->i_blocks)
71 ext2_truncate (inode);
72 ext2_free_inode (inode);
73
74 return;
75no_delete:
76 clear_inode(inode); /* We must guarantee clearing of inode... */
77}
78
Linus Torvalds1da177e2005-04-16 15:20:36 -070079typedef struct {
80 __le32 *p;
81 __le32 key;
82 struct buffer_head *bh;
83} Indirect;
84
85static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
86{
87 p->key = *(p->p = v);
88 p->bh = bh;
89}
90
91static inline int verify_chain(Indirect *from, Indirect *to)
92{
93 while (from <= to && from->key == *from->p)
94 from++;
95 return (from > to);
96}
97
98/**
99 * ext2_block_to_path - parse the block number into array of offsets
100 * @inode: inode in question (we are only interested in its superblock)
101 * @i_block: block number to be parsed
102 * @offsets: array to store the offsets in
103 * @boundary: set this non-zero if the referred-to block is likely to be
104 * followed (on disk) by an indirect block.
105 * To store the locations of file's data ext2 uses a data structure common
106 * for UNIX filesystems - tree of pointers anchored in the inode, with
107 * data blocks at leaves and indirect blocks in intermediate nodes.
108 * This function translates the block number into path in that tree -
109 * return value is the path length and @offsets[n] is the offset of
110 * pointer to (n+1)th node in the nth one. If @block is out of range
111 * (negative or too large) warning is printed and zero returned.
112 *
113 * Note: function doesn't find node addresses, so no IO is needed. All
114 * we need to know is the capacity of indirect blocks (taken from the
115 * inode->i_sb).
116 */
117
118/*
119 * Portability note: the last comparison (check that we fit into triple
120 * indirect block) is spelled differently, because otherwise on an
121 * architecture with 32-bit longs and 8Kb pages we might get into trouble
122 * if our filesystem had 8Kb blocks. We might use long long, but that would
123 * kill us on x86. Oh, well, at least the sign propagation does not matter -
124 * i_block would have to be negative in the very beginning, so we would not
125 * get there at all.
126 */
127
128static int ext2_block_to_path(struct inode *inode,
129 long i_block, int offsets[4], int *boundary)
130{
131 int ptrs = EXT2_ADDR_PER_BLOCK(inode->i_sb);
132 int ptrs_bits = EXT2_ADDR_PER_BLOCK_BITS(inode->i_sb);
133 const long direct_blocks = EXT2_NDIR_BLOCKS,
134 indirect_blocks = ptrs,
135 double_blocks = (1 << (ptrs_bits * 2));
136 int n = 0;
137 int final = 0;
138
139 if (i_block < 0) {
140 ext2_warning (inode->i_sb, "ext2_block_to_path", "block < 0");
141 } else if (i_block < direct_blocks) {
142 offsets[n++] = i_block;
143 final = direct_blocks;
144 } else if ( (i_block -= direct_blocks) < indirect_blocks) {
145 offsets[n++] = EXT2_IND_BLOCK;
146 offsets[n++] = i_block;
147 final = ptrs;
148 } else if ((i_block -= indirect_blocks) < double_blocks) {
149 offsets[n++] = EXT2_DIND_BLOCK;
150 offsets[n++] = i_block >> ptrs_bits;
151 offsets[n++] = i_block & (ptrs - 1);
152 final = ptrs;
153 } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
154 offsets[n++] = EXT2_TIND_BLOCK;
155 offsets[n++] = i_block >> (ptrs_bits * 2);
156 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
157 offsets[n++] = i_block & (ptrs - 1);
158 final = ptrs;
159 } else {
160 ext2_warning (inode->i_sb, "ext2_block_to_path", "block > big");
161 }
162 if (boundary)
Martin J. Bligha686cd82007-10-16 23:30:46 -0700163 *boundary = final - 1 - (i_block & (ptrs - 1));
164
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 return n;
166}
167
168/**
169 * ext2_get_branch - read the chain of indirect blocks leading to data
170 * @inode: inode in question
171 * @depth: depth of the chain (1 - direct pointer, etc.)
172 * @offsets: offsets of pointers in inode/indirect blocks
173 * @chain: place to store the result
174 * @err: here we store the error value
175 *
176 * Function fills the array of triples <key, p, bh> and returns %NULL
177 * if everything went OK or the pointer to the last filled triple
178 * (incomplete one) otherwise. Upon the return chain[i].key contains
179 * the number of (i+1)-th block in the chain (as it is stored in memory,
180 * i.e. little-endian 32-bit), chain[i].p contains the address of that
181 * number (it points into struct inode for i==0 and into the bh->b_data
182 * for i>0) and chain[i].bh points to the buffer_head of i-th indirect
183 * block for i>0 and NULL for i==0. In other words, it holds the block
184 * numbers of the chain, addresses they were taken from (and where we can
185 * verify that chain did not change) and buffer_heads hosting these
186 * numbers.
187 *
188 * Function stops when it stumbles upon zero pointer (absent block)
189 * (pointer to last triple returned, *@err == 0)
190 * or when it gets an IO error reading an indirect block
191 * (ditto, *@err == -EIO)
192 * or when it notices that chain had been changed while it was reading
193 * (ditto, *@err == -EAGAIN)
194 * or when it reads all @depth-1 indirect blocks successfully and finds
195 * the whole chain, all way to the data (returns %NULL, *err == 0).
196 */
197static Indirect *ext2_get_branch(struct inode *inode,
198 int depth,
199 int *offsets,
200 Indirect chain[4],
201 int *err)
202{
203 struct super_block *sb = inode->i_sb;
204 Indirect *p = chain;
205 struct buffer_head *bh;
206
207 *err = 0;
208 /* i_data is not going away, no lock needed */
209 add_chain (chain, NULL, EXT2_I(inode)->i_data + *offsets);
210 if (!p->key)
211 goto no_block;
212 while (--depth) {
213 bh = sb_bread(sb, le32_to_cpu(p->key));
214 if (!bh)
215 goto failure;
216 read_lock(&EXT2_I(inode)->i_meta_lock);
217 if (!verify_chain(chain, p))
218 goto changed;
219 add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
220 read_unlock(&EXT2_I(inode)->i_meta_lock);
221 if (!p->key)
222 goto no_block;
223 }
224 return NULL;
225
226changed:
227 read_unlock(&EXT2_I(inode)->i_meta_lock);
228 brelse(bh);
229 *err = -EAGAIN;
230 goto no_block;
231failure:
232 *err = -EIO;
233no_block:
234 return p;
235}
236
237/**
238 * ext2_find_near - find a place for allocation with sufficient locality
239 * @inode: owner
240 * @ind: descriptor of indirect block.
241 *
Benoit Boissinot1cc8dcf52008-04-21 22:45:55 +0000242 * This function returns the preferred place for block allocation.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243 * It is used when heuristic for sequential allocation fails.
244 * Rules are:
245 * + if there is a block to the left of our position - allocate near it.
246 * + if pointer will live in indirect block - allocate near that block.
247 * + if pointer will live in inode - allocate in the same cylinder group.
248 *
249 * In the latter case we colour the starting block by the callers PID to
250 * prevent it from clashing with concurrent allocations for a different inode
251 * in the same block group. The PID is used here so that functionally related
252 * files will be close-by on-disk.
253 *
254 * Caller must make sure that @ind is valid and will stay that way.
255 */
256
Akinobu Mita4c8b3122008-04-28 02:16:02 -0700257static ext2_fsblk_t ext2_find_near(struct inode *inode, Indirect *ind)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258{
259 struct ext2_inode_info *ei = EXT2_I(inode);
260 __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
261 __le32 *p;
Akinobu Mita4c8b3122008-04-28 02:16:02 -0700262 ext2_fsblk_t bg_start;
263 ext2_fsblk_t colour;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264
265 /* Try to find previous block */
266 for (p = ind->p - 1; p >= start; p--)
267 if (*p)
268 return le32_to_cpu(*p);
269
270 /* No such thing, so let's try location of indirect block */
271 if (ind->bh)
272 return ind->bh->b_blocknr;
273
274 /*
275 * It is going to be refered from inode itself? OK, just put it into
276 * the same cylinder group then.
277 */
Akinobu Mita24097d12008-04-28 02:16:01 -0700278 bg_start = ext2_group_first_block_no(inode->i_sb, ei->i_block_group);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 colour = (current->pid % 16) *
280 (EXT2_BLOCKS_PER_GROUP(inode->i_sb) / 16);
281 return bg_start + colour;
282}
283
284/**
Benoit Boissinot1cc8dcf52008-04-21 22:45:55 +0000285 * ext2_find_goal - find a preferred place for allocation.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286 * @inode: owner
287 * @block: block we want
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 * @partial: pointer to the last triple within a chain
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 *
Martin J. Bligha686cd82007-10-16 23:30:46 -0700290 * Returns preferred place for a block (the goal).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 */
292
Akinobu Mita4c8b3122008-04-28 02:16:02 -0700293static inline ext2_fsblk_t ext2_find_goal(struct inode *inode, long block,
294 Indirect *partial)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295{
Martin J. Bligha686cd82007-10-16 23:30:46 -0700296 struct ext2_block_alloc_info *block_i;
297
298 block_i = EXT2_I(inode)->i_block_alloc_info;
299
300 /*
301 * try the heuristic for sequential allocation,
302 * failing that at least try to get decent locality.
303 */
304 if (block_i && (block == block_i->last_alloc_logical_block + 1)
305 && (block_i->last_alloc_physical_block != 0)) {
306 return block_i->last_alloc_physical_block + 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 }
Martin J. Bligha686cd82007-10-16 23:30:46 -0700308
309 return ext2_find_near(inode, partial);
310}
311
312/**
313 * ext2_blks_to_allocate: Look up the block map and count the number
314 * of direct blocks need to be allocated for the given branch.
315 *
316 * @branch: chain of indirect blocks
317 * @k: number of blocks need for indirect blocks
318 * @blks: number of data blocks to be mapped.
319 * @blocks_to_boundary: the offset in the indirect block
320 *
321 * return the total number of blocks to be allocate, including the
322 * direct and indirect blocks.
323 */
324static int
325ext2_blks_to_allocate(Indirect * branch, int k, unsigned long blks,
326 int blocks_to_boundary)
327{
328 unsigned long count = 0;
329
330 /*
331 * Simple case, [t,d]Indirect block(s) has not allocated yet
332 * then it's clear blocks on that path have not allocated
333 */
334 if (k > 0) {
335 /* right now don't hanel cross boundary allocation */
336 if (blks < blocks_to_boundary + 1)
337 count += blks;
338 else
339 count += blocks_to_boundary + 1;
340 return count;
341 }
342
343 count++;
344 while (count < blks && count <= blocks_to_boundary
345 && le32_to_cpu(*(branch[0].p + count)) == 0) {
346 count++;
347 }
348 return count;
349}
350
351/**
352 * ext2_alloc_blocks: multiple allocate blocks needed for a branch
353 * @indirect_blks: the number of blocks need to allocate for indirect
354 * blocks
355 *
356 * @new_blocks: on return it will store the new block numbers for
357 * the indirect blocks(if needed) and the first direct block,
358 * @blks: on return it will store the total number of allocated
359 * direct blocks
360 */
361static int ext2_alloc_blocks(struct inode *inode,
362 ext2_fsblk_t goal, int indirect_blks, int blks,
363 ext2_fsblk_t new_blocks[4], int *err)
364{
365 int target, i;
366 unsigned long count = 0;
367 int index = 0;
368 ext2_fsblk_t current_block = 0;
369 int ret = 0;
370
371 /*
372 * Here we try to allocate the requested multiple blocks at once,
373 * on a best-effort basis.
374 * To build a branch, we should allocate blocks for
375 * the indirect blocks(if not allocated yet), and at least
376 * the first direct block of this branch. That's the
377 * minimum number of blocks need to allocate(required)
378 */
379 target = blks + indirect_blks;
380
381 while (1) {
382 count = target;
383 /* allocating blocks for indirect blocks and direct blocks */
384 current_block = ext2_new_blocks(inode,goal,&count,err);
385 if (*err)
386 goto failed_out;
387
388 target -= count;
389 /* allocate blocks for indirect blocks */
390 while (index < indirect_blks && count) {
391 new_blocks[index++] = current_block++;
392 count--;
393 }
394
395 if (count > 0)
396 break;
397 }
398
399 /* save the new block number for the first direct block */
400 new_blocks[index] = current_block;
401
402 /* total number of blocks allocated for direct blocks */
403 ret = count;
404 *err = 0;
405 return ret;
406failed_out:
407 for (i = 0; i <index; i++)
408 ext2_free_blocks(inode, new_blocks[i], 1);
409 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410}
411
412/**
413 * ext2_alloc_branch - allocate and set up a chain of blocks.
414 * @inode: owner
415 * @num: depth of the chain (number of blocks to allocate)
416 * @offsets: offsets (in the blocks) to store the pointers to next.
417 * @branch: place to store the chain in.
418 *
419 * This function allocates @num blocks, zeroes out all but the last one,
420 * links them into chain and (if we are synchronous) writes them to disk.
421 * In other words, it prepares a branch that can be spliced onto the
422 * inode. It stores the information about that chain in the branch[], in
423 * the same format as ext2_get_branch() would do. We are calling it after
424 * we had read the existing part of chain and partial points to the last
425 * triple of that (one with zero ->key). Upon the exit we have the same
426 * picture as after the successful ext2_get_block(), excpet that in one
427 * place chain is disconnected - *branch->p is still zero (we did not
428 * set the last link), but branch->key contains the number that should
429 * be placed into *branch->p to fill that gap.
430 *
431 * If allocation fails we free all blocks we've allocated (and forget
432 * their buffer_heads) and return the error value the from failed
433 * ext2_alloc_block() (normally -ENOSPC). Otherwise we set the chain
434 * as described above and return 0.
435 */
436
437static int ext2_alloc_branch(struct inode *inode,
Martin J. Bligha686cd82007-10-16 23:30:46 -0700438 int indirect_blks, int *blks, ext2_fsblk_t goal,
439 int *offsets, Indirect *branch)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440{
441 int blocksize = inode->i_sb->s_blocksize;
Martin J. Bligha686cd82007-10-16 23:30:46 -0700442 int i, n = 0;
443 int err = 0;
444 struct buffer_head *bh;
445 int num;
446 ext2_fsblk_t new_blocks[4];
447 ext2_fsblk_t current_block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448
Martin J. Bligha686cd82007-10-16 23:30:46 -0700449 num = ext2_alloc_blocks(inode, goal, indirect_blks,
450 *blks, new_blocks, &err);
451 if (err)
452 return err;
453
454 branch[0].key = cpu_to_le32(new_blocks[0]);
455 /*
456 * metadata blocks and data blocks are allocated.
457 */
458 for (n = 1; n <= indirect_blks; n++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459 /*
Martin J. Bligha686cd82007-10-16 23:30:46 -0700460 * Get buffer_head for parent block, zero it out
461 * and set the pointer to new one, then send
462 * parent to disk.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463 */
Martin J. Bligha686cd82007-10-16 23:30:46 -0700464 bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
465 branch[n].bh = bh;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 lock_buffer(bh);
467 memset(bh->b_data, 0, blocksize);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468 branch[n].p = (__le32 *) bh->b_data + offsets[n];
Martin J. Bligha686cd82007-10-16 23:30:46 -0700469 branch[n].key = cpu_to_le32(new_blocks[n]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470 *branch[n].p = branch[n].key;
Martin J. Bligha686cd82007-10-16 23:30:46 -0700471 if ( n == indirect_blks) {
472 current_block = new_blocks[n];
473 /*
474 * End of chain, update the last new metablock of
475 * the chain to point to the new allocated
476 * data blocks numbers
477 */
478 for (i=1; i < num; i++)
479 *(branch[n].p + i) = cpu_to_le32(++current_block);
480 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 set_buffer_uptodate(bh);
482 unlock_buffer(bh);
483 mark_buffer_dirty_inode(bh, inode);
484 /* We used to sync bh here if IS_SYNC(inode).
485 * But we now rely upon generic_osync_inode()
486 * and b_inode_buffers. But not for directories.
487 */
488 if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
489 sync_dirty_buffer(bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 }
Martin J. Bligha686cd82007-10-16 23:30:46 -0700491 *blks = num;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 return err;
493}
494
495/**
Martin J. Bligha686cd82007-10-16 23:30:46 -0700496 * ext2_splice_branch - splice the allocated branch onto inode.
497 * @inode: owner
498 * @block: (logical) number of block we are adding
499 * @chain: chain of indirect blocks (with a missing link - see
500 * ext2_alloc_branch)
501 * @where: location of missing link
502 * @num: number of indirect blocks we are adding
503 * @blks: number of direct blocks we are adding
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504 *
Martin J. Bligha686cd82007-10-16 23:30:46 -0700505 * This function fills the missing link and does all housekeeping needed in
506 * inode (->i_blocks, etc.). In case of success we end up with the full
507 * chain to new block and return 0.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 */
Martin J. Bligha686cd82007-10-16 23:30:46 -0700509static void ext2_splice_branch(struct inode *inode,
510 long block, Indirect *where, int num, int blks)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 int i;
Martin J. Bligha686cd82007-10-16 23:30:46 -0700513 struct ext2_block_alloc_info *block_i;
514 ext2_fsblk_t current_block;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515
Martin J. Bligha686cd82007-10-16 23:30:46 -0700516 block_i = EXT2_I(inode)->i_block_alloc_info;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517
Martin J. Bligha686cd82007-10-16 23:30:46 -0700518 /* XXX LOCKING probably should have i_meta_lock ?*/
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519 /* That's it */
520
521 *where->p = where->key;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522
Martin J. Bligha686cd82007-10-16 23:30:46 -0700523 /*
524 * Update the host buffer_head or inode to point to more just allocated
525 * direct blocks blocks
526 */
527 if (num == 0 && blks > 1) {
528 current_block = le32_to_cpu(where->key) + 1;
529 for (i = 1; i < blks; i++)
530 *(where->p + i ) = cpu_to_le32(current_block++);
531 }
532
533 /*
534 * update the most recently allocated logical & physical block
535 * in i_block_alloc_info, to assist find the proper goal block for next
536 * allocation
537 */
538 if (block_i) {
539 block_i->last_alloc_logical_block = block + blks - 1;
540 block_i->last_alloc_physical_block =
541 le32_to_cpu(where[num].key) + blks - 1;
542 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543
544 /* We are done with atomic stuff, now do the rest of housekeeping */
545
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546 /* had we spliced it onto indirect block? */
547 if (where->bh)
548 mark_buffer_dirty_inode(where->bh, inode);
549
Martin J. Bligha686cd82007-10-16 23:30:46 -0700550 inode->i_ctime = CURRENT_TIME_SEC;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 mark_inode_dirty(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552}
553
554/*
555 * Allocation strategy is simple: if we have to allocate something, we will
556 * have to go the whole way to leaf. So let's do it before attaching anything
557 * to tree, set linkage between the newborn blocks, write them if sync is
558 * required, recheck the path, free and repeat if check fails, otherwise
559 * set the last missing link (that will protect us from any truncate-generated
560 * removals - all blocks on the path are immune now) and possibly force the
561 * write on the parent block.
562 * That has a nice additional property: no special recovery from the failed
563 * allocations is needed - we simply release blocks and do not touch anything
564 * reachable from inode.
Martin J. Bligha686cd82007-10-16 23:30:46 -0700565 *
566 * `handle' can be NULL if create == 0.
567 *
Martin J. Bligha686cd82007-10-16 23:30:46 -0700568 * return > 0, # of blocks mapped or allocated.
569 * return = 0, if plain lookup failed.
570 * return < 0, error case.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571 */
Martin J. Bligha686cd82007-10-16 23:30:46 -0700572static int ext2_get_blocks(struct inode *inode,
573 sector_t iblock, unsigned long maxblocks,
574 struct buffer_head *bh_result,
575 int create)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576{
577 int err = -EIO;
578 int offsets[4];
579 Indirect chain[4];
580 Indirect *partial;
Martin J. Bligha686cd82007-10-16 23:30:46 -0700581 ext2_fsblk_t goal;
582 int indirect_blks;
583 int blocks_to_boundary = 0;
584 int depth;
585 struct ext2_inode_info *ei = EXT2_I(inode);
586 int count = 0;
587 ext2_fsblk_t first_block = 0;
588
589 depth = ext2_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590
591 if (depth == 0)
Martin J. Bligha686cd82007-10-16 23:30:46 -0700592 return (err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593reread:
594 partial = ext2_get_branch(inode, depth, offsets, chain, &err);
595
596 /* Simplest case - block found, no allocation needed */
597 if (!partial) {
Martin J. Bligha686cd82007-10-16 23:30:46 -0700598 first_block = le32_to_cpu(chain[depth - 1].key);
599 clear_buffer_new(bh_result); /* What's this do? */
600 count++;
601 /*map more blocks*/
602 while (count < maxblocks && count <= blocks_to_boundary) {
603 ext2_fsblk_t blk;
604
605 if (!verify_chain(chain, partial)) {
606 /*
607 * Indirect block might be removed by
608 * truncate while we were reading it.
609 * Handling of that case: forget what we've
610 * got now, go to reread.
611 */
612 count = 0;
613 goto changed;
614 }
615 blk = le32_to_cpu(*(chain[depth-1].p + count));
616 if (blk == first_block + count)
617 count++;
618 else
619 break;
620 }
621 goto got_it;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622 }
623
624 /* Next simple case - plain lookup or failed read of indirect block */
Martin J. Bligha686cd82007-10-16 23:30:46 -0700625 if (!create || err == -EIO)
626 goto cleanup;
627
628 mutex_lock(&ei->truncate_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629
630 /*
Martin J. Bligha686cd82007-10-16 23:30:46 -0700631 * Okay, we need to do block allocation. Lazily initialize the block
632 * allocation info here if necessary
633 */
634 if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
635 ext2_init_block_alloc_info(inode);
636
Akinobu Mitafb01bfd2008-02-06 01:40:16 -0800637 goal = ext2_find_goal(inode, iblock, partial);
Martin J. Bligha686cd82007-10-16 23:30:46 -0700638
639 /* the number of blocks need to allocate for [d,t]indirect blocks */
640 indirect_blks = (chain + depth) - partial - 1;
641 /*
642 * Next look up the indirect map to count the totoal number of
643 * direct blocks to allocate for this branch.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644 */
Martin J. Bligha686cd82007-10-16 23:30:46 -0700645 count = ext2_blks_to_allocate(partial, indirect_blks,
646 maxblocks, blocks_to_boundary);
647 /*
648 * XXX ???? Block out ext2_truncate while we alter the tree
649 */
650 err = ext2_alloc_branch(inode, indirect_blks, &count, goal,
651 offsets + (partial - chain), partial);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652
Martin J. Bligha686cd82007-10-16 23:30:46 -0700653 if (err) {
654 mutex_unlock(&ei->truncate_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 goto cleanup;
Martin J. Bligha686cd82007-10-16 23:30:46 -0700656 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657
Carsten Otte6d791252005-06-23 22:05:26 -0700658 if (ext2_use_xip(inode->i_sb)) {
659 /*
660 * we need to clear the block
661 */
662 err = ext2_clear_xip_target (inode,
663 le32_to_cpu(chain[depth-1].key));
Martin J. Bligha686cd82007-10-16 23:30:46 -0700664 if (err) {
665 mutex_unlock(&ei->truncate_mutex);
Carsten Otte6d791252005-06-23 22:05:26 -0700666 goto cleanup;
Martin J. Bligha686cd82007-10-16 23:30:46 -0700667 }
Carsten Otte6d791252005-06-23 22:05:26 -0700668 }
669
Martin J. Bligha686cd82007-10-16 23:30:46 -0700670 ext2_splice_branch(inode, iblock, partial, indirect_blks, count);
671 mutex_unlock(&ei->truncate_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672 set_buffer_new(bh_result);
Martin J. Bligha686cd82007-10-16 23:30:46 -0700673got_it:
674 map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
675 if (count > blocks_to_boundary)
676 set_buffer_boundary(bh_result);
677 err = count;
678 /* Clean up and exit */
679 partial = chain + depth - 1; /* the whole chain */
680cleanup:
681 while (partial > chain) {
682 brelse(partial->bh);
683 partial--;
684 }
685 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686changed:
687 while (partial > chain) {
688 brelse(partial->bh);
689 partial--;
690 }
691 goto reread;
692}
693
Martin J. Bligha686cd82007-10-16 23:30:46 -0700694int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
695{
696 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
697 int ret = ext2_get_blocks(inode, iblock, max_blocks,
698 bh_result, create);
699 if (ret > 0) {
700 bh_result->b_size = (ret << inode->i_blkbits);
701 ret = 0;
702 }
703 return ret;
704
705}
706
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707static int ext2_writepage(struct page *page, struct writeback_control *wbc)
708{
709 return block_write_full_page(page, ext2_get_block, wbc);
710}
711
712static int ext2_readpage(struct file *file, struct page *page)
713{
714 return mpage_readpage(page, ext2_get_block);
715}
716
717static int
718ext2_readpages(struct file *file, struct address_space *mapping,
719 struct list_head *pages, unsigned nr_pages)
720{
721 return mpage_readpages(mapping, pages, nr_pages, ext2_get_block);
722}
723
Nick Pigginf34fb6e2007-10-16 01:25:04 -0700724int __ext2_write_begin(struct file *file, struct address_space *mapping,
725 loff_t pos, unsigned len, unsigned flags,
726 struct page **pagep, void **fsdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727{
Nick Pigginf34fb6e2007-10-16 01:25:04 -0700728 return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
729 ext2_get_block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730}
731
732static int
Nick Pigginf34fb6e2007-10-16 01:25:04 -0700733ext2_write_begin(struct file *file, struct address_space *mapping,
734 loff_t pos, unsigned len, unsigned flags,
735 struct page **pagep, void **fsdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736{
Nick Pigginf34fb6e2007-10-16 01:25:04 -0700737 *pagep = NULL;
738 return __ext2_write_begin(file, mapping, pos, len, flags, pagep,fsdata);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739}
740
Nick Piggin03158cd2007-10-16 01:25:25 -0700741static int
742ext2_nobh_write_begin(struct file *file, struct address_space *mapping,
743 loff_t pos, unsigned len, unsigned flags,
744 struct page **pagep, void **fsdata)
745{
746 /*
747 * Dir-in-pagecache still uses ext2_write_begin. Would have to rework
748 * directory handling code to pass around offsets rather than struct
749 * pages in order to make this work easily.
750 */
751 return nobh_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
752 ext2_get_block);
753}
754
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755static int ext2_nobh_writepage(struct page *page,
756 struct writeback_control *wbc)
757{
758 return nobh_writepage(page, ext2_get_block, wbc);
759}
760
761static sector_t ext2_bmap(struct address_space *mapping, sector_t block)
762{
763 return generic_block_bmap(mapping,block,ext2_get_block);
764}
765
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766static ssize_t
767ext2_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
768 loff_t offset, unsigned long nr_segs)
769{
770 struct file *file = iocb->ki_filp;
771 struct inode *inode = file->f_mapping->host;
772
773 return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
Badari Pulavarty1d8fa7a2006-03-26 01:38:02 -0800774 offset, nr_segs, ext2_get_block, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775}
776
777static int
778ext2_writepages(struct address_space *mapping, struct writeback_control *wbc)
779{
780 return mpage_writepages(mapping, wbc, ext2_get_block);
781}
782
Christoph Hellwigf5e54d62006-06-28 04:26:44 -0700783const struct address_space_operations ext2_aops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784 .readpage = ext2_readpage,
785 .readpages = ext2_readpages,
786 .writepage = ext2_writepage,
787 .sync_page = block_sync_page,
Nick Pigginf34fb6e2007-10-16 01:25:04 -0700788 .write_begin = ext2_write_begin,
789 .write_end = generic_write_end,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790 .bmap = ext2_bmap,
791 .direct_IO = ext2_direct_IO,
792 .writepages = ext2_writepages,
Christoph Lametere965f962006-02-01 03:05:41 -0800793 .migratepage = buffer_migrate_page,
Hisashi Hifumi8ab22b92008-07-28 15:46:36 -0700794 .is_partially_uptodate = block_is_partially_uptodate,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795};
796
Christoph Hellwigf5e54d62006-06-28 04:26:44 -0700797const struct address_space_operations ext2_aops_xip = {
Carsten Otte6d791252005-06-23 22:05:26 -0700798 .bmap = ext2_bmap,
Nick Piggin70688e42008-04-28 02:13:02 -0700799 .get_xip_mem = ext2_get_xip_mem,
Carsten Otte6d791252005-06-23 22:05:26 -0700800};
801
Christoph Hellwigf5e54d62006-06-28 04:26:44 -0700802const struct address_space_operations ext2_nobh_aops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 .readpage = ext2_readpage,
804 .readpages = ext2_readpages,
805 .writepage = ext2_nobh_writepage,
806 .sync_page = block_sync_page,
Nick Piggin03158cd2007-10-16 01:25:25 -0700807 .write_begin = ext2_nobh_write_begin,
808 .write_end = nobh_write_end,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700809 .bmap = ext2_bmap,
810 .direct_IO = ext2_direct_IO,
811 .writepages = ext2_writepages,
Christoph Lametere965f962006-02-01 03:05:41 -0800812 .migratepage = buffer_migrate_page,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700813};
814
815/*
816 * Probably it should be a library function... search for first non-zero word
817 * or memcmp with zero_page, whatever is better for particular architecture.
818 * Linus?
819 */
820static inline int all_zeroes(__le32 *p, __le32 *q)
821{
822 while (p < q)
823 if (*p++)
824 return 0;
825 return 1;
826}
827
828/**
829 * ext2_find_shared - find the indirect blocks for partial truncation.
830 * @inode: inode in question
831 * @depth: depth of the affected branch
832 * @offsets: offsets of pointers in that branch (see ext2_block_to_path)
833 * @chain: place to store the pointers to partial indirect blocks
834 * @top: place to the (detached) top of branch
835 *
836 * This is a helper function used by ext2_truncate().
837 *
838 * When we do truncate() we may have to clean the ends of several indirect
839 * blocks but leave the blocks themselves alive. Block is partially
840 * truncated if some data below the new i_size is refered from it (and
841 * it is on the path to the first completely truncated data block, indeed).
842 * We have to free the top of that path along with everything to the right
843 * of the path. Since no allocation past the truncation point is possible
844 * until ext2_truncate() finishes, we may safely do the latter, but top
845 * of branch may require special attention - pageout below the truncation
846 * point might try to populate it.
847 *
848 * We atomically detach the top of branch from the tree, store the block
849 * number of its root in *@top, pointers to buffer_heads of partially
850 * truncated blocks - in @chain[].bh and pointers to their last elements
851 * that should not be removed - in @chain[].p. Return value is the pointer
852 * to last filled element of @chain.
853 *
854 * The work left to caller to do the actual freeing of subtrees:
855 * a) free the subtree starting from *@top
856 * b) free the subtrees whose roots are stored in
857 * (@chain[i].p+1 .. end of @chain[i].bh->b_data)
858 * c) free the subtrees growing from the inode past the @chain[0].p
859 * (no partially truncated stuff there).
860 */
861
862static Indirect *ext2_find_shared(struct inode *inode,
863 int depth,
864 int offsets[4],
865 Indirect chain[4],
866 __le32 *top)
867{
868 Indirect *partial, *p;
869 int k, err;
870
871 *top = 0;
872 for (k = depth; k > 1 && !offsets[k-1]; k--)
873 ;
874 partial = ext2_get_branch(inode, k, offsets, chain, &err);
875 if (!partial)
876 partial = chain + k-1;
877 /*
878 * If the branch acquired continuation since we've looked at it -
879 * fine, it should all survive and (new) top doesn't belong to us.
880 */
881 write_lock(&EXT2_I(inode)->i_meta_lock);
882 if (!partial->key && *partial->p) {
883 write_unlock(&EXT2_I(inode)->i_meta_lock);
884 goto no_top;
885 }
886 for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
887 ;
888 /*
889 * OK, we've found the last block that must survive. The rest of our
890 * branch should be detached before unlocking. However, if that rest
891 * of branch is all ours and does not grow immediately from the inode
892 * it's easier to cheat and just decrement partial->p.
893 */
894 if (p == chain + k - 1 && p > chain) {
895 p->p--;
896 } else {
897 *top = *p->p;
898 *p->p = 0;
899 }
900 write_unlock(&EXT2_I(inode)->i_meta_lock);
901
902 while(partial > p)
903 {
904 brelse(partial->bh);
905 partial--;
906 }
907no_top:
908 return partial;
909}
910
911/**
912 * ext2_free_data - free a list of data blocks
913 * @inode: inode we are dealing with
914 * @p: array of block numbers
915 * @q: points immediately past the end of array
916 *
917 * We are freeing all blocks refered from that array (numbers are
918 * stored as little-endian 32-bit) and updating @inode->i_blocks
919 * appropriately.
920 */
921static inline void ext2_free_data(struct inode *inode, __le32 *p, __le32 *q)
922{
923 unsigned long block_to_free = 0, count = 0;
924 unsigned long nr;
925
926 for ( ; p < q ; p++) {
927 nr = le32_to_cpu(*p);
928 if (nr) {
929 *p = 0;
930 /* accumulate blocks to free if they're contiguous */
931 if (count == 0)
932 goto free_this;
933 else if (block_to_free == nr - count)
934 count++;
935 else {
936 mark_inode_dirty(inode);
937 ext2_free_blocks (inode, block_to_free, count);
938 free_this:
939 block_to_free = nr;
940 count = 1;
941 }
942 }
943 }
944 if (count > 0) {
945 mark_inode_dirty(inode);
946 ext2_free_blocks (inode, block_to_free, count);
947 }
948}
949
950/**
951 * ext2_free_branches - free an array of branches
952 * @inode: inode we are dealing with
953 * @p: array of block numbers
954 * @q: pointer immediately past the end of array
955 * @depth: depth of the branches to free
956 *
957 * We are freeing all blocks refered from these branches (numbers are
958 * stored as little-endian 32-bit) and updating @inode->i_blocks
959 * appropriately.
960 */
961static void ext2_free_branches(struct inode *inode, __le32 *p, __le32 *q, int depth)
962{
963 struct buffer_head * bh;
964 unsigned long nr;
965
966 if (depth--) {
967 int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
968 for ( ; p < q ; p++) {
969 nr = le32_to_cpu(*p);
970 if (!nr)
971 continue;
972 *p = 0;
973 bh = sb_bread(inode->i_sb, nr);
974 /*
975 * A read failure? Report error and clear slot
976 * (should be rare).
977 */
978 if (!bh) {
979 ext2_error(inode->i_sb, "ext2_free_branches",
980 "Read failure, inode=%ld, block=%ld",
981 inode->i_ino, nr);
982 continue;
983 }
984 ext2_free_branches(inode,
985 (__le32*)bh->b_data,
986 (__le32*)bh->b_data + addr_per_block,
987 depth);
988 bforget(bh);
989 ext2_free_blocks(inode, nr, 1);
990 mark_inode_dirty(inode);
991 }
992 } else
993 ext2_free_data(inode, p, q);
994}
995
Martin J. Bligha686cd82007-10-16 23:30:46 -0700996void ext2_truncate(struct inode *inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997{
998 __le32 *i_data = EXT2_I(inode)->i_data;
Martin J. Bligha686cd82007-10-16 23:30:46 -0700999 struct ext2_inode_info *ei = EXT2_I(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001000 int addr_per_block = EXT2_ADDR_PER_BLOCK(inode->i_sb);
1001 int offsets[4];
1002 Indirect chain[4];
1003 Indirect *partial;
1004 __le32 nr = 0;
1005 int n;
1006 long iblock;
1007 unsigned blocksize;
1008
1009 if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
1010 S_ISLNK(inode->i_mode)))
1011 return;
1012 if (ext2_inode_is_fast_symlink(inode))
1013 return;
1014 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
1015 return;
1016
Linus Torvalds1da177e2005-04-16 15:20:36 -07001017 blocksize = inode->i_sb->s_blocksize;
1018 iblock = (inode->i_size + blocksize-1)
1019 >> EXT2_BLOCK_SIZE_BITS(inode->i_sb);
1020
Carsten Otte6d791252005-06-23 22:05:26 -07001021 if (mapping_is_xip(inode->i_mapping))
1022 xip_truncate_page(inode->i_mapping, inode->i_size);
1023 else if (test_opt(inode->i_sb, NOBH))
Nick Piggin03158cd2007-10-16 01:25:25 -07001024 nobh_truncate_page(inode->i_mapping,
1025 inode->i_size, ext2_get_block);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001026 else
1027 block_truncate_page(inode->i_mapping,
1028 inode->i_size, ext2_get_block);
1029
1030 n = ext2_block_to_path(inode, iblock, offsets, NULL);
1031 if (n == 0)
1032 return;
1033
Martin J. Bligha686cd82007-10-16 23:30:46 -07001034 /*
1035 * From here we block out all ext2_get_block() callers who want to
1036 * modify the block allocation tree.
1037 */
1038 mutex_lock(&ei->truncate_mutex);
1039
Linus Torvalds1da177e2005-04-16 15:20:36 -07001040 if (n == 1) {
1041 ext2_free_data(inode, i_data+offsets[0],
1042 i_data + EXT2_NDIR_BLOCKS);
1043 goto do_indirects;
1044 }
1045
1046 partial = ext2_find_shared(inode, n, offsets, chain, &nr);
1047 /* Kill the top of shared branch (already detached) */
1048 if (nr) {
1049 if (partial == chain)
1050 mark_inode_dirty(inode);
1051 else
1052 mark_buffer_dirty_inode(partial->bh, inode);
1053 ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
1054 }
1055 /* Clear the ends of indirect blocks on the shared branch */
1056 while (partial > chain) {
1057 ext2_free_branches(inode,
1058 partial->p + 1,
1059 (__le32*)partial->bh->b_data+addr_per_block,
1060 (chain+n-1) - partial);
1061 mark_buffer_dirty_inode(partial->bh, inode);
1062 brelse (partial->bh);
1063 partial--;
1064 }
1065do_indirects:
1066 /* Kill the remaining (whole) subtrees */
1067 switch (offsets[0]) {
1068 default:
1069 nr = i_data[EXT2_IND_BLOCK];
1070 if (nr) {
1071 i_data[EXT2_IND_BLOCK] = 0;
1072 mark_inode_dirty(inode);
1073 ext2_free_branches(inode, &nr, &nr+1, 1);
1074 }
1075 case EXT2_IND_BLOCK:
1076 nr = i_data[EXT2_DIND_BLOCK];
1077 if (nr) {
1078 i_data[EXT2_DIND_BLOCK] = 0;
1079 mark_inode_dirty(inode);
1080 ext2_free_branches(inode, &nr, &nr+1, 2);
1081 }
1082 case EXT2_DIND_BLOCK:
1083 nr = i_data[EXT2_TIND_BLOCK];
1084 if (nr) {
1085 i_data[EXT2_TIND_BLOCK] = 0;
1086 mark_inode_dirty(inode);
1087 ext2_free_branches(inode, &nr, &nr+1, 3);
1088 }
1089 case EXT2_TIND_BLOCK:
1090 ;
1091 }
Martin J. Bligha686cd82007-10-16 23:30:46 -07001092
1093 ext2_discard_reservation(inode);
1094
1095 mutex_unlock(&ei->truncate_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001096 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
1097 if (inode_needs_sync(inode)) {
1098 sync_mapping_buffers(inode->i_mapping);
1099 ext2_sync_inode (inode);
1100 } else {
1101 mark_inode_dirty(inode);
1102 }
1103}
1104
1105static struct ext2_inode *ext2_get_inode(struct super_block *sb, ino_t ino,
1106 struct buffer_head **p)
1107{
1108 struct buffer_head * bh;
1109 unsigned long block_group;
1110 unsigned long block;
1111 unsigned long offset;
1112 struct ext2_group_desc * gdp;
1113
1114 *p = NULL;
1115 if ((ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb)) ||
1116 ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
1117 goto Einval;
1118
1119 block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
Eric Sandeenef2fb672007-10-16 23:26:30 -07001120 gdp = ext2_get_group_desc(sb, block_group, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001121 if (!gdp)
1122 goto Egdp;
1123 /*
1124 * Figure out the offset within the block group inode table
1125 */
1126 offset = ((ino - 1) % EXT2_INODES_PER_GROUP(sb)) * EXT2_INODE_SIZE(sb);
1127 block = le32_to_cpu(gdp->bg_inode_table) +
1128 (offset >> EXT2_BLOCK_SIZE_BITS(sb));
1129 if (!(bh = sb_bread(sb, block)))
1130 goto Eio;
1131
1132 *p = bh;
1133 offset &= (EXT2_BLOCK_SIZE(sb) - 1);
1134 return (struct ext2_inode *) (bh->b_data + offset);
1135
1136Einval:
1137 ext2_error(sb, "ext2_get_inode", "bad inode number: %lu",
1138 (unsigned long) ino);
1139 return ERR_PTR(-EINVAL);
1140Eio:
1141 ext2_error(sb, "ext2_get_inode",
1142 "unable to read inode block - inode=%lu, block=%lu",
1143 (unsigned long) ino, block);
1144Egdp:
1145 return ERR_PTR(-EIO);
1146}
1147
1148void ext2_set_inode_flags(struct inode *inode)
1149{
1150 unsigned int flags = EXT2_I(inode)->i_flags;
1151
1152 inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
1153 if (flags & EXT2_SYNC_FL)
1154 inode->i_flags |= S_SYNC;
1155 if (flags & EXT2_APPEND_FL)
1156 inode->i_flags |= S_APPEND;
1157 if (flags & EXT2_IMMUTABLE_FL)
1158 inode->i_flags |= S_IMMUTABLE;
1159 if (flags & EXT2_NOATIME_FL)
1160 inode->i_flags |= S_NOATIME;
1161 if (flags & EXT2_DIRSYNC_FL)
1162 inode->i_flags |= S_DIRSYNC;
1163}
1164
Jan Kara4f99ed62007-05-08 00:31:04 -07001165/* Propagate flags from i_flags to EXT2_I(inode)->i_flags */
1166void ext2_get_inode_flags(struct ext2_inode_info *ei)
1167{
1168 unsigned int flags = ei->vfs_inode.i_flags;
1169
1170 ei->i_flags &= ~(EXT2_SYNC_FL|EXT2_APPEND_FL|
1171 EXT2_IMMUTABLE_FL|EXT2_NOATIME_FL|EXT2_DIRSYNC_FL);
1172 if (flags & S_SYNC)
1173 ei->i_flags |= EXT2_SYNC_FL;
1174 if (flags & S_APPEND)
1175 ei->i_flags |= EXT2_APPEND_FL;
1176 if (flags & S_IMMUTABLE)
1177 ei->i_flags |= EXT2_IMMUTABLE_FL;
1178 if (flags & S_NOATIME)
1179 ei->i_flags |= EXT2_NOATIME_FL;
1180 if (flags & S_DIRSYNC)
1181 ei->i_flags |= EXT2_DIRSYNC_FL;
1182}
1183
David Howells52fcf702008-02-07 00:15:35 -08001184struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001185{
David Howells52fcf702008-02-07 00:15:35 -08001186 struct ext2_inode_info *ei;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001187 struct buffer_head * bh;
David Howells52fcf702008-02-07 00:15:35 -08001188 struct ext2_inode *raw_inode;
1189 struct inode *inode;
1190 long ret = -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001191 int n;
1192
David Howells52fcf702008-02-07 00:15:35 -08001193 inode = iget_locked(sb, ino);
1194 if (!inode)
1195 return ERR_PTR(-ENOMEM);
1196 if (!(inode->i_state & I_NEW))
1197 return inode;
1198
1199 ei = EXT2_I(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200#ifdef CONFIG_EXT2_FS_POSIX_ACL
1201 ei->i_acl = EXT2_ACL_NOT_CACHED;
1202 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
1203#endif
Martin J. Bligha686cd82007-10-16 23:30:46 -07001204 ei->i_block_alloc_info = NULL;
1205
David Howells52fcf702008-02-07 00:15:35 -08001206 raw_inode = ext2_get_inode(inode->i_sb, ino, &bh);
1207 if (IS_ERR(raw_inode)) {
1208 ret = PTR_ERR(raw_inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209 goto bad_inode;
David Howells52fcf702008-02-07 00:15:35 -08001210 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211
1212 inode->i_mode = le16_to_cpu(raw_inode->i_mode);
1213 inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
1214 inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
1215 if (!(test_opt (inode->i_sb, NO_UID32))) {
1216 inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
1217 inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
1218 }
1219 inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
1220 inode->i_size = le32_to_cpu(raw_inode->i_size);
Markus Rechberger4d7bf112007-05-08 00:23:39 -07001221 inode->i_atime.tv_sec = (signed)le32_to_cpu(raw_inode->i_atime);
1222 inode->i_ctime.tv_sec = (signed)le32_to_cpu(raw_inode->i_ctime);
1223 inode->i_mtime.tv_sec = (signed)le32_to_cpu(raw_inode->i_mtime);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001224 inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
1225 ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
1226 /* We now have enough fields to check if the inode was active or not.
1227 * This is needed because nfsd might try to access dead inodes
1228 * the test is that same one that e2fsck uses
1229 * NeilBrown 1999oct15
1230 */
1231 if (inode->i_nlink == 0 && (inode->i_mode == 0 || ei->i_dtime)) {
1232 /* this inode is deleted */
1233 brelse (bh);
David Howells52fcf702008-02-07 00:15:35 -08001234 ret = -ESTALE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001235 goto bad_inode;
1236 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001237 inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
1238 ei->i_flags = le32_to_cpu(raw_inode->i_flags);
1239 ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
1240 ei->i_frag_no = raw_inode->i_frag;
1241 ei->i_frag_size = raw_inode->i_fsize;
1242 ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
1243 ei->i_dir_acl = 0;
1244 if (S_ISREG(inode->i_mode))
1245 inode->i_size |= ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
1246 else
1247 ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
1248 ei->i_dtime = 0;
1249 inode->i_generation = le32_to_cpu(raw_inode->i_generation);
1250 ei->i_state = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001251 ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
1252 ei->i_dir_start_lookup = 0;
1253
1254 /*
1255 * NOTE! The in-memory inode i_data array is in little-endian order
1256 * even on big-endian machines: we do NOT byteswap the block numbers!
1257 */
1258 for (n = 0; n < EXT2_N_BLOCKS; n++)
1259 ei->i_data[n] = raw_inode->i_block[n];
1260
1261 if (S_ISREG(inode->i_mode)) {
1262 inode->i_op = &ext2_file_inode_operations;
Carsten Otte6d791252005-06-23 22:05:26 -07001263 if (ext2_use_xip(inode->i_sb)) {
1264 inode->i_mapping->a_ops = &ext2_aops_xip;
1265 inode->i_fop = &ext2_xip_file_operations;
1266 } else if (test_opt(inode->i_sb, NOBH)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267 inode->i_mapping->a_ops = &ext2_nobh_aops;
Carsten Otte6d791252005-06-23 22:05:26 -07001268 inode->i_fop = &ext2_file_operations;
1269 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001270 inode->i_mapping->a_ops = &ext2_aops;
Carsten Otte6d791252005-06-23 22:05:26 -07001271 inode->i_fop = &ext2_file_operations;
1272 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001273 } else if (S_ISDIR(inode->i_mode)) {
1274 inode->i_op = &ext2_dir_inode_operations;
1275 inode->i_fop = &ext2_dir_operations;
1276 if (test_opt(inode->i_sb, NOBH))
1277 inode->i_mapping->a_ops = &ext2_nobh_aops;
1278 else
1279 inode->i_mapping->a_ops = &ext2_aops;
1280 } else if (S_ISLNK(inode->i_mode)) {
1281 if (ext2_inode_is_fast_symlink(inode))
1282 inode->i_op = &ext2_fast_symlink_inode_operations;
1283 else {
1284 inode->i_op = &ext2_symlink_inode_operations;
1285 if (test_opt(inode->i_sb, NOBH))
1286 inode->i_mapping->a_ops = &ext2_nobh_aops;
1287 else
1288 inode->i_mapping->a_ops = &ext2_aops;
1289 }
1290 } else {
1291 inode->i_op = &ext2_special_inode_operations;
1292 if (raw_inode->i_block[0])
1293 init_special_inode(inode, inode->i_mode,
1294 old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
1295 else
1296 init_special_inode(inode, inode->i_mode,
1297 new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
1298 }
1299 brelse (bh);
1300 ext2_set_inode_flags(inode);
David Howells52fcf702008-02-07 00:15:35 -08001301 unlock_new_inode(inode);
1302 return inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001303
1304bad_inode:
David Howells52fcf702008-02-07 00:15:35 -08001305 iget_failed(inode);
1306 return ERR_PTR(ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001307}
1308
1309static int ext2_update_inode(struct inode * inode, int do_sync)
1310{
1311 struct ext2_inode_info *ei = EXT2_I(inode);
1312 struct super_block *sb = inode->i_sb;
1313 ino_t ino = inode->i_ino;
1314 uid_t uid = inode->i_uid;
1315 gid_t gid = inode->i_gid;
1316 struct buffer_head * bh;
1317 struct ext2_inode * raw_inode = ext2_get_inode(sb, ino, &bh);
1318 int n;
1319 int err = 0;
1320
1321 if (IS_ERR(raw_inode))
1322 return -EIO;
1323
1324 /* For fields not not tracking in the in-memory inode,
1325 * initialise them to zero for new inodes. */
1326 if (ei->i_state & EXT2_STATE_NEW)
1327 memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size);
1328
Jan Kara4f99ed62007-05-08 00:31:04 -07001329 ext2_get_inode_flags(ei);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001330 raw_inode->i_mode = cpu_to_le16(inode->i_mode);
1331 if (!(test_opt(sb, NO_UID32))) {
1332 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(uid));
1333 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(gid));
1334/*
1335 * Fix up interoperability with old kernels. Otherwise, old inodes get
1336 * re-used with the upper 16 bits of the uid/gid intact
1337 */
1338 if (!ei->i_dtime) {
1339 raw_inode->i_uid_high = cpu_to_le16(high_16_bits(uid));
1340 raw_inode->i_gid_high = cpu_to_le16(high_16_bits(gid));
1341 } else {
1342 raw_inode->i_uid_high = 0;
1343 raw_inode->i_gid_high = 0;
1344 }
1345 } else {
1346 raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(uid));
1347 raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(gid));
1348 raw_inode->i_uid_high = 0;
1349 raw_inode->i_gid_high = 0;
1350 }
1351 raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
1352 raw_inode->i_size = cpu_to_le32(inode->i_size);
1353 raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
1354 raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
1355 raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
1356
1357 raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
1358 raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
1359 raw_inode->i_flags = cpu_to_le32(ei->i_flags);
1360 raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
1361 raw_inode->i_frag = ei->i_frag_no;
1362 raw_inode->i_fsize = ei->i_frag_size;
1363 raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
1364 if (!S_ISREG(inode->i_mode))
1365 raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
1366 else {
1367 raw_inode->i_size_high = cpu_to_le32(inode->i_size >> 32);
1368 if (inode->i_size > 0x7fffffffULL) {
1369 if (!EXT2_HAS_RO_COMPAT_FEATURE(sb,
1370 EXT2_FEATURE_RO_COMPAT_LARGE_FILE) ||
1371 EXT2_SB(sb)->s_es->s_rev_level ==
1372 cpu_to_le32(EXT2_GOOD_OLD_REV)) {
1373 /* If this is the first large file
1374 * created, add a flag to the superblock.
1375 */
1376 lock_kernel();
1377 ext2_update_dynamic_rev(sb);
1378 EXT2_SET_RO_COMPAT_FEATURE(sb,
1379 EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
1380 unlock_kernel();
1381 ext2_write_super(sb);
1382 }
1383 }
1384 }
1385
1386 raw_inode->i_generation = cpu_to_le32(inode->i_generation);
1387 if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
1388 if (old_valid_dev(inode->i_rdev)) {
1389 raw_inode->i_block[0] =
1390 cpu_to_le32(old_encode_dev(inode->i_rdev));
1391 raw_inode->i_block[1] = 0;
1392 } else {
1393 raw_inode->i_block[0] = 0;
1394 raw_inode->i_block[1] =
1395 cpu_to_le32(new_encode_dev(inode->i_rdev));
1396 raw_inode->i_block[2] = 0;
1397 }
1398 } else for (n = 0; n < EXT2_N_BLOCKS; n++)
1399 raw_inode->i_block[n] = ei->i_data[n];
1400 mark_buffer_dirty(bh);
1401 if (do_sync) {
1402 sync_dirty_buffer(bh);
1403 if (buffer_req(bh) && !buffer_uptodate(bh)) {
1404 printk ("IO error syncing ext2 inode [%s:%08lx]\n",
1405 sb->s_id, (unsigned long) ino);
1406 err = -EIO;
1407 }
1408 }
1409 ei->i_state &= ~EXT2_STATE_NEW;
1410 brelse (bh);
1411 return err;
1412}
1413
1414int ext2_write_inode(struct inode *inode, int wait)
1415{
1416 return ext2_update_inode(inode, wait);
1417}
1418
1419int ext2_sync_inode(struct inode *inode)
1420{
1421 struct writeback_control wbc = {
1422 .sync_mode = WB_SYNC_ALL,
1423 .nr_to_write = 0, /* sys_fsync did this */
1424 };
1425 return sync_inode(inode, &wbc);
1426}
1427
1428int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
1429{
1430 struct inode *inode = dentry->d_inode;
1431 int error;
1432
1433 error = inode_change_ok(inode, iattr);
1434 if (error)
1435 return error;
1436 if ((iattr->ia_valid & ATTR_UID && iattr->ia_uid != inode->i_uid) ||
1437 (iattr->ia_valid & ATTR_GID && iattr->ia_gid != inode->i_gid)) {
1438 error = DQUOT_TRANSFER(inode, iattr) ? -EDQUOT : 0;
1439 if (error)
1440 return error;
1441 }
1442 error = inode_setattr(inode, iattr);
1443 if (!error && (iattr->ia_valid & ATTR_MODE))
1444 error = ext2_acl_chmod(inode);
1445 return error;
1446}