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1 | /* |
2 | * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. |
3 | * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved. |
4 | * |
5 | * This copyrighted material is made available to anyone wishing to use, |
6 | * modify, copy, or redistribute it subject to the terms and conditions |
7 | * of the GNU General Public License version 2. |
8 | */ |
9 | |
10 | #include <linux/spinlock.h> |
11 | #include <linux/completion.h> |
12 | #include <linux/buffer_head.h> |
13 | #include <linux/gfs2_ondisk.h> |
14 | #include <linux/crc32.h> |
15 | |
16 | #include "gfs2.h" |
17 | #include "incore.h" |
18 | #include "bmap.h" |
19 | #include "glock.h" |
20 | #include "inode.h" |
21 | #include "meta_io.h" |
22 | #include "quota.h" |
23 | #include "rgrp.h" |
24 | #include "super.h" |
25 | #include "trans.h" |
26 | #include "dir.h" |
27 | #include "util.h" |
28 | #include "trace_gfs2.h" |
29 | |
30 | /* This doesn't need to be that large as max 64 bit pointers in a 4k |
31 | * block is 512, so __u16 is fine for that. It saves stack space to |
32 | * keep it small. |
33 | */ |
34 | struct metapath { |
35 | struct buffer_head *mp_bh[GFS2_MAX_META_HEIGHT]; |
36 | __u16 mp_list[GFS2_MAX_META_HEIGHT]; |
37 | }; |
38 | |
39 | typedef int (*block_call_t) (struct gfs2_inode *ip, struct buffer_head *dibh, |
40 | struct buffer_head *bh, __be64 *top, |
41 | __be64 *bottom, unsigned int height, |
42 | void *data); |
43 | |
44 | struct strip_mine { |
45 | int sm_first; |
46 | unsigned int sm_height; |
47 | }; |
48 | |
49 | /** |
50 | * gfs2_unstuffer_page - unstuff a stuffed inode into a block cached by a page |
51 | * @ip: the inode |
52 | * @dibh: the dinode buffer |
53 | * @block: the block number that was allocated |
54 | * @page: The (optional) page. This is looked up if @page is NULL |
55 | * |
56 | * Returns: errno |
57 | */ |
58 | |
59 | static int gfs2_unstuffer_page(struct gfs2_inode *ip, struct buffer_head *dibh, |
60 | u64 block, struct page *page) |
61 | { |
62 | struct inode *inode = &ip->i_inode; |
63 | struct buffer_head *bh; |
64 | int release = 0; |
65 | |
66 | if (!page || page->index) { |
67 | page = grab_cache_page(inode->i_mapping, 0); |
68 | if (!page) |
69 | return -ENOMEM; |
70 | release = 1; |
71 | } |
72 | |
73 | if (!PageUptodate(page)) { |
74 | void *kaddr = kmap(page); |
75 | u64 dsize = i_size_read(inode); |
76 | |
77 | if (dsize > (dibh->b_size - sizeof(struct gfs2_dinode))) |
78 | dsize = dibh->b_size - sizeof(struct gfs2_dinode); |
79 | |
80 | memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode), dsize); |
81 | memset(kaddr + dsize, 0, PAGE_CACHE_SIZE - dsize); |
82 | kunmap(page); |
83 | |
84 | SetPageUptodate(page); |
85 | } |
86 | |
87 | if (!page_has_buffers(page)) |
88 | create_empty_buffers(page, 1 << inode->i_blkbits, |
89 | (1 << BH_Uptodate)); |
90 | |
91 | bh = page_buffers(page); |
92 | |
93 | if (!buffer_mapped(bh)) |
94 | map_bh(bh, inode->i_sb, block); |
95 | |
96 | set_buffer_uptodate(bh); |
97 | if (!gfs2_is_jdata(ip)) |
98 | mark_buffer_dirty(bh); |
99 | if (!gfs2_is_writeback(ip)) |
100 | gfs2_trans_add_bh(ip->i_gl, bh, 0); |
101 | |
102 | if (release) { |
103 | unlock_page(page); |
104 | page_cache_release(page); |
105 | } |
106 | |
107 | return 0; |
108 | } |
109 | |
110 | /** |
111 | * gfs2_unstuff_dinode - Unstuff a dinode when the data has grown too big |
112 | * @ip: The GFS2 inode to unstuff |
113 | * @page: The (optional) page. This is looked up if the @page is NULL |
114 | * |
115 | * This routine unstuffs a dinode and returns it to a "normal" state such |
116 | * that the height can be grown in the traditional way. |
117 | * |
118 | * Returns: errno |
119 | */ |
120 | |
121 | int gfs2_unstuff_dinode(struct gfs2_inode *ip, struct page *page) |
122 | { |
123 | struct buffer_head *bh, *dibh; |
124 | struct gfs2_dinode *di; |
125 | u64 block = 0; |
126 | int isdir = gfs2_is_dir(ip); |
127 | int error; |
128 | |
129 | down_write(&ip->i_rw_mutex); |
130 | |
131 | error = gfs2_meta_inode_buffer(ip, &dibh); |
132 | if (error) |
133 | goto out; |
134 | |
135 | if (i_size_read(&ip->i_inode)) { |
136 | /* Get a free block, fill it with the stuffed data, |
137 | and write it out to disk */ |
138 | |
139 | unsigned int n = 1; |
140 | error = gfs2_alloc_block(ip, &block, &n); |
141 | if (error) |
142 | goto out_brelse; |
143 | if (isdir) { |
144 | gfs2_trans_add_unrevoke(GFS2_SB(&ip->i_inode), block, 1); |
145 | error = gfs2_dir_get_new_buffer(ip, block, &bh); |
146 | if (error) |
147 | goto out_brelse; |
148 | gfs2_buffer_copy_tail(bh, sizeof(struct gfs2_meta_header), |
149 | dibh, sizeof(struct gfs2_dinode)); |
150 | brelse(bh); |
151 | } else { |
152 | error = gfs2_unstuffer_page(ip, dibh, block, page); |
153 | if (error) |
154 | goto out_brelse; |
155 | } |
156 | } |
157 | |
158 | /* Set up the pointer to the new block */ |
159 | |
160 | gfs2_trans_add_bh(ip->i_gl, dibh, 1); |
161 | di = (struct gfs2_dinode *)dibh->b_data; |
162 | gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode)); |
163 | |
164 | if (i_size_read(&ip->i_inode)) { |
165 | *(__be64 *)(di + 1) = cpu_to_be64(block); |
166 | gfs2_add_inode_blocks(&ip->i_inode, 1); |
167 | di->di_blocks = cpu_to_be64(gfs2_get_inode_blocks(&ip->i_inode)); |
168 | } |
169 | |
170 | ip->i_height = 1; |
171 | di->di_height = cpu_to_be16(1); |
172 | |
173 | out_brelse: |
174 | brelse(dibh); |
175 | out: |
176 | up_write(&ip->i_rw_mutex); |
177 | return error; |
178 | } |
179 | |
180 | |
181 | /** |
182 | * find_metapath - Find path through the metadata tree |
183 | * @sdp: The superblock |
184 | * @mp: The metapath to return the result in |
185 | * @block: The disk block to look up |
186 | * @height: The pre-calculated height of the metadata tree |
187 | * |
188 | * This routine returns a struct metapath structure that defines a path |
189 | * through the metadata of inode "ip" to get to block "block". |
190 | * |
191 | * Example: |
192 | * Given: "ip" is a height 3 file, "offset" is 101342453, and this is a |
193 | * filesystem with a blocksize of 4096. |
194 | * |
195 | * find_metapath() would return a struct metapath structure set to: |
196 | * mp_offset = 101342453, mp_height = 3, mp_list[0] = 0, mp_list[1] = 48, |
197 | * and mp_list[2] = 165. |
198 | * |
199 | * That means that in order to get to the block containing the byte at |
200 | * offset 101342453, we would load the indirect block pointed to by pointer |
201 | * 0 in the dinode. We would then load the indirect block pointed to by |
202 | * pointer 48 in that indirect block. We would then load the data block |
203 | * pointed to by pointer 165 in that indirect block. |
204 | * |
205 | * ---------------------------------------- |
206 | * | Dinode | | |
207 | * | | 4| |
208 | * | |0 1 2 3 4 5 9| |
209 | * | | 6| |
210 | * ---------------------------------------- |
211 | * | |
212 | * | |
213 | * V |
214 | * ---------------------------------------- |
215 | * | Indirect Block | |
216 | * | 5| |
217 | * | 4 4 4 4 4 5 5 1| |
218 | * |0 5 6 7 8 9 0 1 2| |
219 | * ---------------------------------------- |
220 | * | |
221 | * | |
222 | * V |
223 | * ---------------------------------------- |
224 | * | Indirect Block | |
225 | * | 1 1 1 1 1 5| |
226 | * | 6 6 6 6 6 1| |
227 | * |0 3 4 5 6 7 2| |
228 | * ---------------------------------------- |
229 | * | |
230 | * | |
231 | * V |
232 | * ---------------------------------------- |
233 | * | Data block containing offset | |
234 | * | 101342453 | |
235 | * | | |
236 | * | | |
237 | * ---------------------------------------- |
238 | * |
239 | */ |
240 | |
241 | static void find_metapath(const struct gfs2_sbd *sdp, u64 block, |
242 | struct metapath *mp, unsigned int height) |
243 | { |
244 | unsigned int i; |
245 | |
246 | for (i = height; i--;) |
247 | mp->mp_list[i] = do_div(block, sdp->sd_inptrs); |
248 | |
249 | } |
250 | |
251 | static inline unsigned int metapath_branch_start(const struct metapath *mp) |
252 | { |
253 | if (mp->mp_list[0] == 0) |
254 | return 2; |
255 | return 1; |
256 | } |
257 | |
258 | /** |
259 | * metapointer - Return pointer to start of metadata in a buffer |
260 | * @height: The metadata height (0 = dinode) |
261 | * @mp: The metapath |
262 | * |
263 | * Return a pointer to the block number of the next height of the metadata |
264 | * tree given a buffer containing the pointer to the current height of the |
265 | * metadata tree. |
266 | */ |
267 | |
268 | static inline __be64 *metapointer(unsigned int height, const struct metapath *mp) |
269 | { |
270 | struct buffer_head *bh = mp->mp_bh[height]; |
271 | unsigned int head_size = (height > 0) ? |
272 | sizeof(struct gfs2_meta_header) : sizeof(struct gfs2_dinode); |
273 | return ((__be64 *)(bh->b_data + head_size)) + mp->mp_list[height]; |
274 | } |
275 | |
276 | /** |
277 | * lookup_metapath - Walk the metadata tree to a specific point |
278 | * @ip: The inode |
279 | * @mp: The metapath |
280 | * |
281 | * Assumes that the inode's buffer has already been looked up and |
282 | * hooked onto mp->mp_bh[0] and that the metapath has been initialised |
283 | * by find_metapath(). |
284 | * |
285 | * If this function encounters part of the tree which has not been |
286 | * allocated, it returns the current height of the tree at the point |
287 | * at which it found the unallocated block. Blocks which are found are |
288 | * added to the mp->mp_bh[] list. |
289 | * |
290 | * Returns: error or height of metadata tree |
291 | */ |
292 | |
293 | static int lookup_metapath(struct gfs2_inode *ip, struct metapath *mp) |
294 | { |
295 | unsigned int end_of_metadata = ip->i_height - 1; |
296 | unsigned int x; |
297 | __be64 *ptr; |
298 | u64 dblock; |
299 | int ret; |
300 | |
301 | for (x = 0; x < end_of_metadata; x++) { |
302 | ptr = metapointer(x, mp); |
303 | dblock = be64_to_cpu(*ptr); |
304 | if (!dblock) |
305 | return x + 1; |
306 | |
307 | ret = gfs2_meta_indirect_buffer(ip, x+1, dblock, 0, &mp->mp_bh[x+1]); |
308 | if (ret) |
309 | return ret; |
310 | } |
311 | |
312 | return ip->i_height; |
313 | } |
314 | |
315 | static inline void release_metapath(struct metapath *mp) |
316 | { |
317 | int i; |
318 | |
319 | for (i = 0; i < GFS2_MAX_META_HEIGHT; i++) { |
320 | if (mp->mp_bh[i] == NULL) |
321 | break; |
322 | brelse(mp->mp_bh[i]); |
323 | } |
324 | } |
325 | |
326 | /** |
327 | * gfs2_extent_length - Returns length of an extent of blocks |
328 | * @start: Start of the buffer |
329 | * @len: Length of the buffer in bytes |
330 | * @ptr: Current position in the buffer |
331 | * @limit: Max extent length to return (0 = unlimited) |
332 | * @eob: Set to 1 if we hit "end of block" |
333 | * |
334 | * If the first block is zero (unallocated) it will return the number of |
335 | * unallocated blocks in the extent, otherwise it will return the number |
336 | * of contiguous blocks in the extent. |
337 | * |
338 | * Returns: The length of the extent (minimum of one block) |
339 | */ |
340 | |
341 | static inline unsigned int gfs2_extent_length(void *start, unsigned int len, __be64 *ptr, unsigned limit, int *eob) |
342 | { |
343 | const __be64 *end = (start + len); |
344 | const __be64 *first = ptr; |
345 | u64 d = be64_to_cpu(*ptr); |
346 | |
347 | *eob = 0; |
348 | do { |
349 | ptr++; |
350 | if (ptr >= end) |
351 | break; |
352 | if (limit && --limit == 0) |
353 | break; |
354 | if (d) |
355 | d++; |
356 | } while(be64_to_cpu(*ptr) == d); |
357 | if (ptr >= end) |
358 | *eob = 1; |
359 | return (ptr - first); |
360 | } |
361 | |
362 | static inline void bmap_lock(struct gfs2_inode *ip, int create) |
363 | { |
364 | if (create) |
365 | down_write(&ip->i_rw_mutex); |
366 | else |
367 | down_read(&ip->i_rw_mutex); |
368 | } |
369 | |
370 | static inline void bmap_unlock(struct gfs2_inode *ip, int create) |
371 | { |
372 | if (create) |
373 | up_write(&ip->i_rw_mutex); |
374 | else |
375 | up_read(&ip->i_rw_mutex); |
376 | } |
377 | |
378 | static inline __be64 *gfs2_indirect_init(struct metapath *mp, |
379 | struct gfs2_glock *gl, unsigned int i, |
380 | unsigned offset, u64 bn) |
381 | { |
382 | __be64 *ptr = (__be64 *)(mp->mp_bh[i - 1]->b_data + |
383 | ((i > 1) ? sizeof(struct gfs2_meta_header) : |
384 | sizeof(struct gfs2_dinode))); |
385 | BUG_ON(i < 1); |
386 | BUG_ON(mp->mp_bh[i] != NULL); |
387 | mp->mp_bh[i] = gfs2_meta_new(gl, bn); |
388 | gfs2_trans_add_bh(gl, mp->mp_bh[i], 1); |
389 | gfs2_metatype_set(mp->mp_bh[i], GFS2_METATYPE_IN, GFS2_FORMAT_IN); |
390 | gfs2_buffer_clear_tail(mp->mp_bh[i], sizeof(struct gfs2_meta_header)); |
391 | ptr += offset; |
392 | *ptr = cpu_to_be64(bn); |
393 | return ptr; |
394 | } |
395 | |
396 | enum alloc_state { |
397 | ALLOC_DATA = 0, |
398 | ALLOC_GROW_DEPTH = 1, |
399 | ALLOC_GROW_HEIGHT = 2, |
400 | /* ALLOC_UNSTUFF = 3, TBD and rather complicated */ |
401 | }; |
402 | |
403 | /** |
404 | * gfs2_bmap_alloc - Build a metadata tree of the requested height |
405 | * @inode: The GFS2 inode |
406 | * @lblock: The logical starting block of the extent |
407 | * @bh_map: This is used to return the mapping details |
408 | * @mp: The metapath |
409 | * @sheight: The starting height (i.e. whats already mapped) |
410 | * @height: The height to build to |
411 | * @maxlen: The max number of data blocks to alloc |
412 | * |
413 | * In this routine we may have to alloc: |
414 | * i) Indirect blocks to grow the metadata tree height |
415 | * ii) Indirect blocks to fill in lower part of the metadata tree |
416 | * iii) Data blocks |
417 | * |
418 | * The function is in two parts. The first part works out the total |
419 | * number of blocks which we need. The second part does the actual |
420 | * allocation asking for an extent at a time (if enough contiguous free |
421 | * blocks are available, there will only be one request per bmap call) |
422 | * and uses the state machine to initialise the blocks in order. |
423 | * |
424 | * Returns: errno on error |
425 | */ |
426 | |
427 | static int gfs2_bmap_alloc(struct inode *inode, const sector_t lblock, |
428 | struct buffer_head *bh_map, struct metapath *mp, |
429 | const unsigned int sheight, |
430 | const unsigned int height, |
431 | const unsigned int maxlen) |
432 | { |
433 | struct gfs2_inode *ip = GFS2_I(inode); |
434 | struct gfs2_sbd *sdp = GFS2_SB(inode); |
435 | struct buffer_head *dibh = mp->mp_bh[0]; |
436 | u64 bn, dblock = 0; |
437 | unsigned n, i, blks, alloced = 0, iblks = 0, branch_start = 0; |
438 | unsigned dblks = 0; |
439 | unsigned ptrs_per_blk; |
440 | const unsigned end_of_metadata = height - 1; |
441 | int eob = 0; |
442 | enum alloc_state state; |
443 | __be64 *ptr; |
444 | __be64 zero_bn = 0; |
445 | |
446 | BUG_ON(sheight < 1); |
447 | BUG_ON(dibh == NULL); |
448 | |
449 | gfs2_trans_add_bh(ip->i_gl, dibh, 1); |
450 | |
451 | if (height == sheight) { |
452 | struct buffer_head *bh; |
453 | /* Bottom indirect block exists, find unalloced extent size */ |
454 | ptr = metapointer(end_of_metadata, mp); |
455 | bh = mp->mp_bh[end_of_metadata]; |
456 | dblks = gfs2_extent_length(bh->b_data, bh->b_size, ptr, maxlen, |
457 | &eob); |
458 | BUG_ON(dblks < 1); |
459 | state = ALLOC_DATA; |
460 | } else { |
461 | /* Need to allocate indirect blocks */ |
462 | ptrs_per_blk = height > 1 ? sdp->sd_inptrs : sdp->sd_diptrs; |
463 | dblks = min(maxlen, ptrs_per_blk - mp->mp_list[end_of_metadata]); |
464 | if (height == ip->i_height) { |
465 | /* Writing into existing tree, extend tree down */ |
466 | iblks = height - sheight; |
467 | state = ALLOC_GROW_DEPTH; |
468 | } else { |
469 | /* Building up tree height */ |
470 | state = ALLOC_GROW_HEIGHT; |
471 | iblks = height - ip->i_height; |
472 | branch_start = metapath_branch_start(mp); |
473 | iblks += (height - branch_start); |
474 | } |
475 | } |
476 | |
477 | /* start of the second part of the function (state machine) */ |
478 | |
479 | blks = dblks + iblks; |
480 | i = sheight; |
481 | do { |
482 | int error; |
483 | n = blks - alloced; |
484 | error = gfs2_alloc_block(ip, &bn, &n); |
485 | if (error) |
486 | return error; |
487 | alloced += n; |
488 | if (state != ALLOC_DATA || gfs2_is_jdata(ip)) |
489 | gfs2_trans_add_unrevoke(sdp, bn, n); |
490 | switch (state) { |
491 | /* Growing height of tree */ |
492 | case ALLOC_GROW_HEIGHT: |
493 | if (i == 1) { |
494 | ptr = (__be64 *)(dibh->b_data + |
495 | sizeof(struct gfs2_dinode)); |
496 | zero_bn = *ptr; |
497 | } |
498 | for (; i - 1 < height - ip->i_height && n > 0; i++, n--) |
499 | gfs2_indirect_init(mp, ip->i_gl, i, 0, bn++); |
500 | if (i - 1 == height - ip->i_height) { |
501 | i--; |
502 | gfs2_buffer_copy_tail(mp->mp_bh[i], |
503 | sizeof(struct gfs2_meta_header), |
504 | dibh, sizeof(struct gfs2_dinode)); |
505 | gfs2_buffer_clear_tail(dibh, |
506 | sizeof(struct gfs2_dinode) + |
507 | sizeof(__be64)); |
508 | ptr = (__be64 *)(mp->mp_bh[i]->b_data + |
509 | sizeof(struct gfs2_meta_header)); |
510 | *ptr = zero_bn; |
511 | state = ALLOC_GROW_DEPTH; |
512 | for(i = branch_start; i < height; i++) { |
513 | if (mp->mp_bh[i] == NULL) |
514 | break; |
515 | brelse(mp->mp_bh[i]); |
516 | mp->mp_bh[i] = NULL; |
517 | } |
518 | i = branch_start; |
519 | } |
520 | if (n == 0) |
521 | break; |
522 | /* Branching from existing tree */ |
523 | case ALLOC_GROW_DEPTH: |
524 | if (i > 1 && i < height) |
525 | gfs2_trans_add_bh(ip->i_gl, mp->mp_bh[i-1], 1); |
526 | for (; i < height && n > 0; i++, n--) |
527 | gfs2_indirect_init(mp, ip->i_gl, i, |
528 | mp->mp_list[i-1], bn++); |
529 | if (i == height) |
530 | state = ALLOC_DATA; |
531 | if (n == 0) |
532 | break; |
533 | /* Tree complete, adding data blocks */ |
534 | case ALLOC_DATA: |
535 | BUG_ON(n > dblks); |
536 | BUG_ON(mp->mp_bh[end_of_metadata] == NULL); |
537 | gfs2_trans_add_bh(ip->i_gl, mp->mp_bh[end_of_metadata], 1); |
538 | dblks = n; |
539 | ptr = metapointer(end_of_metadata, mp); |
540 | dblock = bn; |
541 | while (n-- > 0) |
542 | *ptr++ = cpu_to_be64(bn++); |
543 | break; |
544 | } |
545 | } while ((state != ALLOC_DATA) || !dblock); |
546 | |
547 | ip->i_height = height; |
548 | gfs2_add_inode_blocks(&ip->i_inode, alloced); |
549 | gfs2_dinode_out(ip, mp->mp_bh[0]->b_data); |
550 | map_bh(bh_map, inode->i_sb, dblock); |
551 | bh_map->b_size = dblks << inode->i_blkbits; |
552 | set_buffer_new(bh_map); |
553 | return 0; |
554 | } |
555 | |
556 | /** |
557 | * gfs2_block_map - Map a block from an inode to a disk block |
558 | * @inode: The inode |
559 | * @lblock: The logical block number |
560 | * @bh_map: The bh to be mapped |
561 | * @create: True if its ok to alloc blocks to satify the request |
562 | * |
563 | * Sets buffer_mapped() if successful, sets buffer_boundary() if a |
564 | * read of metadata will be required before the next block can be |
565 | * mapped. Sets buffer_new() if new blocks were allocated. |
566 | * |
567 | * Returns: errno |
568 | */ |
569 | |
570 | int gfs2_block_map(struct inode *inode, sector_t lblock, |
571 | struct buffer_head *bh_map, int create) |
572 | { |
573 | struct gfs2_inode *ip = GFS2_I(inode); |
574 | struct gfs2_sbd *sdp = GFS2_SB(inode); |
575 | unsigned int bsize = sdp->sd_sb.sb_bsize; |
576 | const unsigned int maxlen = bh_map->b_size >> inode->i_blkbits; |
577 | const u64 *arr = sdp->sd_heightsize; |
578 | __be64 *ptr; |
579 | u64 size; |
580 | struct metapath mp; |
581 | int ret; |
582 | int eob; |
583 | unsigned int len; |
584 | struct buffer_head *bh; |
585 | u8 height; |
586 | |
587 | BUG_ON(maxlen == 0); |
588 | |
589 | memset(mp.mp_bh, 0, sizeof(mp.mp_bh)); |
590 | bmap_lock(ip, create); |
591 | clear_buffer_mapped(bh_map); |
592 | clear_buffer_new(bh_map); |
593 | clear_buffer_boundary(bh_map); |
594 | trace_gfs2_bmap(ip, bh_map, lblock, create, 1); |
595 | if (gfs2_is_dir(ip)) { |
596 | bsize = sdp->sd_jbsize; |
597 | arr = sdp->sd_jheightsize; |
598 | } |
599 | |
600 | ret = gfs2_meta_inode_buffer(ip, &mp.mp_bh[0]); |
601 | if (ret) |
602 | goto out; |
603 | |
604 | height = ip->i_height; |
605 | size = (lblock + 1) * bsize; |
606 | while (size > arr[height]) |
607 | height++; |
608 | find_metapath(sdp, lblock, &mp, height); |
609 | ret = 1; |
610 | if (height > ip->i_height || gfs2_is_stuffed(ip)) |
611 | goto do_alloc; |
612 | ret = lookup_metapath(ip, &mp); |
613 | if (ret < 0) |
614 | goto out; |
615 | if (ret != ip->i_height) |
616 | goto do_alloc; |
617 | ptr = metapointer(ip->i_height - 1, &mp); |
618 | if (*ptr == 0) |
619 | goto do_alloc; |
620 | map_bh(bh_map, inode->i_sb, be64_to_cpu(*ptr)); |
621 | bh = mp.mp_bh[ip->i_height - 1]; |
622 | len = gfs2_extent_length(bh->b_data, bh->b_size, ptr, maxlen, &eob); |
623 | bh_map->b_size = (len << inode->i_blkbits); |
624 | if (eob) |
625 | set_buffer_boundary(bh_map); |
626 | ret = 0; |
627 | out: |
628 | release_metapath(&mp); |
629 | trace_gfs2_bmap(ip, bh_map, lblock, create, ret); |
630 | bmap_unlock(ip, create); |
631 | return ret; |
632 | |
633 | do_alloc: |
634 | /* All allocations are done here, firstly check create flag */ |
635 | if (!create) { |
636 | BUG_ON(gfs2_is_stuffed(ip)); |
637 | ret = 0; |
638 | goto out; |
639 | } |
640 | |
641 | /* At this point ret is the tree depth of already allocated blocks */ |
642 | ret = gfs2_bmap_alloc(inode, lblock, bh_map, &mp, ret, height, maxlen); |
643 | goto out; |
644 | } |
645 | |
646 | /* |
647 | * Deprecated: do not use in new code |
648 | */ |
649 | int gfs2_extent_map(struct inode *inode, u64 lblock, int *new, u64 *dblock, unsigned *extlen) |
650 | { |
651 | struct buffer_head bh = { .b_state = 0, .b_blocknr = 0 }; |
652 | int ret; |
653 | int create = *new; |
654 | |
655 | BUG_ON(!extlen); |
656 | BUG_ON(!dblock); |
657 | BUG_ON(!new); |
658 | |
659 | bh.b_size = 1 << (inode->i_blkbits + (create ? 0 : 5)); |
660 | ret = gfs2_block_map(inode, lblock, &bh, create); |
661 | *extlen = bh.b_size >> inode->i_blkbits; |
662 | *dblock = bh.b_blocknr; |
663 | if (buffer_new(&bh)) |
664 | *new = 1; |
665 | else |
666 | *new = 0; |
667 | return ret; |
668 | } |
669 | |
670 | /** |
671 | * recursive_scan - recursively scan through the end of a file |
672 | * @ip: the inode |
673 | * @dibh: the dinode buffer |
674 | * @mp: the path through the metadata to the point to start |
675 | * @height: the height the recursion is at |
676 | * @block: the indirect block to look at |
677 | * @first: 1 if this is the first block |
678 | * @bc: the call to make for each piece of metadata |
679 | * @data: data opaque to this function to pass to @bc |
680 | * |
681 | * When this is first called @height and @block should be zero and |
682 | * @first should be 1. |
683 | * |
684 | * Returns: errno |
685 | */ |
686 | |
687 | static int recursive_scan(struct gfs2_inode *ip, struct buffer_head *dibh, |
688 | struct metapath *mp, unsigned int height, |
689 | u64 block, int first, block_call_t bc, |
690 | void *data) |
691 | { |
692 | struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); |
693 | struct buffer_head *bh = NULL; |
694 | __be64 *top, *bottom; |
695 | u64 bn; |
696 | int error; |
697 | int mh_size = sizeof(struct gfs2_meta_header); |
698 | |
699 | if (!height) { |
700 | error = gfs2_meta_inode_buffer(ip, &bh); |
701 | if (error) |
702 | return error; |
703 | dibh = bh; |
704 | |
705 | top = (__be64 *)(bh->b_data + sizeof(struct gfs2_dinode)) + mp->mp_list[0]; |
706 | bottom = (__be64 *)(bh->b_data + sizeof(struct gfs2_dinode)) + sdp->sd_diptrs; |
707 | } else { |
708 | error = gfs2_meta_indirect_buffer(ip, height, block, 0, &bh); |
709 | if (error) |
710 | return error; |
711 | |
712 | top = (__be64 *)(bh->b_data + mh_size) + |
713 | (first ? mp->mp_list[height] : 0); |
714 | |
715 | bottom = (__be64 *)(bh->b_data + mh_size) + sdp->sd_inptrs; |
716 | } |
717 | |
718 | error = bc(ip, dibh, bh, top, bottom, height, data); |
719 | if (error) |
720 | goto out; |
721 | |
722 | if (height < ip->i_height - 1) |
723 | for (; top < bottom; top++, first = 0) { |
724 | if (!*top) |
725 | continue; |
726 | |
727 | bn = be64_to_cpu(*top); |
728 | |
729 | error = recursive_scan(ip, dibh, mp, height + 1, bn, |
730 | first, bc, data); |
731 | if (error) |
732 | break; |
733 | } |
734 | |
735 | out: |
736 | brelse(bh); |
737 | return error; |
738 | } |
739 | |
740 | /** |
741 | * do_strip - Look for a layer a particular layer of the file and strip it off |
742 | * @ip: the inode |
743 | * @dibh: the dinode buffer |
744 | * @bh: A buffer of pointers |
745 | * @top: The first pointer in the buffer |
746 | * @bottom: One more than the last pointer |
747 | * @height: the height this buffer is at |
748 | * @data: a pointer to a struct strip_mine |
749 | * |
750 | * Returns: errno |
751 | */ |
752 | |
753 | static int do_strip(struct gfs2_inode *ip, struct buffer_head *dibh, |
754 | struct buffer_head *bh, __be64 *top, __be64 *bottom, |
755 | unsigned int height, void *data) |
756 | { |
757 | struct strip_mine *sm = data; |
758 | struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); |
759 | struct gfs2_rgrp_list rlist; |
760 | u64 bn, bstart; |
761 | u32 blen, btotal; |
762 | __be64 *p; |
763 | unsigned int rg_blocks = 0; |
764 | int metadata; |
765 | unsigned int revokes = 0; |
766 | int x; |
767 | int error = 0; |
768 | |
769 | if (!*top) |
770 | sm->sm_first = 0; |
771 | |
772 | if (height != sm->sm_height) |
773 | return 0; |
774 | |
775 | if (sm->sm_first) { |
776 | top++; |
777 | sm->sm_first = 0; |
778 | } |
779 | |
780 | metadata = (height != ip->i_height - 1); |
781 | if (metadata) |
782 | revokes = (height) ? sdp->sd_inptrs : sdp->sd_diptrs; |
783 | else if (ip->i_depth) |
784 | revokes = sdp->sd_inptrs; |
785 | |
786 | if (ip != GFS2_I(sdp->sd_rindex)) |
787 | error = gfs2_rindex_hold(sdp, &ip->i_alloc->al_ri_gh); |
788 | else if (!sdp->sd_rgrps) |
789 | error = gfs2_ri_update(ip); |
790 | |
791 | if (error) |
792 | return error; |
793 | |
794 | memset(&rlist, 0, sizeof(struct gfs2_rgrp_list)); |
795 | bstart = 0; |
796 | blen = 0; |
797 | |
798 | for (p = top; p < bottom; p++) { |
799 | if (!*p) |
800 | continue; |
801 | |
802 | bn = be64_to_cpu(*p); |
803 | |
804 | if (bstart + blen == bn) |
805 | blen++; |
806 | else { |
807 | if (bstart) |
808 | gfs2_rlist_add(sdp, &rlist, bstart); |
809 | |
810 | bstart = bn; |
811 | blen = 1; |
812 | } |
813 | } |
814 | |
815 | if (bstart) |
816 | gfs2_rlist_add(sdp, &rlist, bstart); |
817 | else |
818 | goto out; /* Nothing to do */ |
819 | |
820 | gfs2_rlist_alloc(&rlist, LM_ST_EXCLUSIVE); |
821 | |
822 | for (x = 0; x < rlist.rl_rgrps; x++) { |
823 | struct gfs2_rgrpd *rgd; |
824 | rgd = rlist.rl_ghs[x].gh_gl->gl_object; |
825 | rg_blocks += rgd->rd_length; |
826 | } |
827 | |
828 | error = gfs2_glock_nq_m(rlist.rl_rgrps, rlist.rl_ghs); |
829 | if (error) |
830 | goto out_rlist; |
831 | |
832 | error = gfs2_trans_begin(sdp, rg_blocks + RES_DINODE + |
833 | RES_INDIRECT + RES_STATFS + RES_QUOTA, |
834 | revokes); |
835 | if (error) |
836 | goto out_rg_gunlock; |
837 | |
838 | down_write(&ip->i_rw_mutex); |
839 | |
840 | gfs2_trans_add_bh(ip->i_gl, dibh, 1); |
841 | gfs2_trans_add_bh(ip->i_gl, bh, 1); |
842 | |
843 | bstart = 0; |
844 | blen = 0; |
845 | btotal = 0; |
846 | |
847 | for (p = top; p < bottom; p++) { |
848 | if (!*p) |
849 | continue; |
850 | |
851 | bn = be64_to_cpu(*p); |
852 | |
853 | if (bstart + blen == bn) |
854 | blen++; |
855 | else { |
856 | if (bstart) { |
857 | if (metadata) |
858 | __gfs2_free_meta(ip, bstart, blen); |
859 | else |
860 | __gfs2_free_data(ip, bstart, blen); |
861 | |
862 | btotal += blen; |
863 | } |
864 | |
865 | bstart = bn; |
866 | blen = 1; |
867 | } |
868 | |
869 | *p = 0; |
870 | gfs2_add_inode_blocks(&ip->i_inode, -1); |
871 | } |
872 | if (bstart) { |
873 | if (metadata) |
874 | __gfs2_free_meta(ip, bstart, blen); |
875 | else |
876 | __gfs2_free_data(ip, bstart, blen); |
877 | |
878 | btotal += blen; |
879 | } |
880 | |
881 | gfs2_statfs_change(sdp, 0, +btotal, 0); |
882 | gfs2_quota_change(ip, -(s64)btotal, ip->i_inode.i_uid, |
883 | ip->i_inode.i_gid); |
884 | |
885 | ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME; |
886 | |
887 | gfs2_dinode_out(ip, dibh->b_data); |
888 | |
889 | up_write(&ip->i_rw_mutex); |
890 | |
891 | gfs2_trans_end(sdp); |
892 | |
893 | out_rg_gunlock: |
894 | gfs2_glock_dq_m(rlist.rl_rgrps, rlist.rl_ghs); |
895 | out_rlist: |
896 | gfs2_rlist_free(&rlist); |
897 | out: |
898 | if (ip != GFS2_I(sdp->sd_rindex)) |
899 | gfs2_glock_dq_uninit(&ip->i_alloc->al_ri_gh); |
900 | return error; |
901 | } |
902 | |
903 | /** |
904 | * gfs2_block_truncate_page - Deal with zeroing out data for truncate |
905 | * |
906 | * This is partly borrowed from ext3. |
907 | */ |
908 | static int gfs2_block_truncate_page(struct address_space *mapping, loff_t from) |
909 | { |
910 | struct inode *inode = mapping->host; |
911 | struct gfs2_inode *ip = GFS2_I(inode); |
912 | unsigned long index = from >> PAGE_CACHE_SHIFT; |
913 | unsigned offset = from & (PAGE_CACHE_SIZE-1); |
914 | unsigned blocksize, iblock, length, pos; |
915 | struct buffer_head *bh; |
916 | struct page *page; |
917 | int err; |
918 | |
919 | page = grab_cache_page(mapping, index); |
920 | if (!page) |
921 | return 0; |
922 | |
923 | blocksize = inode->i_sb->s_blocksize; |
924 | length = blocksize - (offset & (blocksize - 1)); |
925 | iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits); |
926 | |
927 | if (!page_has_buffers(page)) |
928 | create_empty_buffers(page, blocksize, 0); |
929 | |
930 | /* Find the buffer that contains "offset" */ |
931 | bh = page_buffers(page); |
932 | pos = blocksize; |
933 | while (offset >= pos) { |
934 | bh = bh->b_this_page; |
935 | iblock++; |
936 | pos += blocksize; |
937 | } |
938 | |
939 | err = 0; |
940 | |
941 | if (!buffer_mapped(bh)) { |
942 | gfs2_block_map(inode, iblock, bh, 0); |
943 | /* unmapped? It's a hole - nothing to do */ |
944 | if (!buffer_mapped(bh)) |
945 | goto unlock; |
946 | } |
947 | |
948 | /* Ok, it's mapped. Make sure it's up-to-date */ |
949 | if (PageUptodate(page)) |
950 | set_buffer_uptodate(bh); |
951 | |
952 | if (!buffer_uptodate(bh)) { |
953 | err = -EIO; |
954 | ll_rw_block(READ, 1, &bh); |
955 | wait_on_buffer(bh); |
956 | /* Uhhuh. Read error. Complain and punt. */ |
957 | if (!buffer_uptodate(bh)) |
958 | goto unlock; |
959 | err = 0; |
960 | } |
961 | |
962 | if (!gfs2_is_writeback(ip)) |
963 | gfs2_trans_add_bh(ip->i_gl, bh, 0); |
964 | |
965 | zero_user(page, offset, length); |
966 | mark_buffer_dirty(bh); |
967 | unlock: |
968 | unlock_page(page); |
969 | page_cache_release(page); |
970 | return err; |
971 | } |
972 | |
973 | static int trunc_start(struct inode *inode, u64 oldsize, u64 newsize) |
974 | { |
975 | struct gfs2_inode *ip = GFS2_I(inode); |
976 | struct gfs2_sbd *sdp = GFS2_SB(inode); |
977 | struct address_space *mapping = inode->i_mapping; |
978 | struct buffer_head *dibh; |
979 | int journaled = gfs2_is_jdata(ip); |
980 | int error; |
981 | |
982 | error = gfs2_trans_begin(sdp, |
983 | RES_DINODE + (journaled ? RES_JDATA : 0), 0); |
984 | if (error) |
985 | return error; |
986 | |
987 | error = gfs2_meta_inode_buffer(ip, &dibh); |
988 | if (error) |
989 | goto out; |
990 | |
991 | gfs2_trans_add_bh(ip->i_gl, dibh, 1); |
992 | |
993 | if (gfs2_is_stuffed(ip)) { |
994 | gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode) + newsize); |
995 | } else { |
996 | if (newsize & (u64)(sdp->sd_sb.sb_bsize - 1)) { |
997 | error = gfs2_block_truncate_page(mapping, newsize); |
998 | if (error) |
999 | goto out_brelse; |
1000 | } |
1001 | ip->i_diskflags |= GFS2_DIF_TRUNC_IN_PROG; |
1002 | } |
1003 | |
1004 | i_size_write(inode, newsize); |
1005 | ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME; |
1006 | gfs2_dinode_out(ip, dibh->b_data); |
1007 | |
1008 | truncate_pagecache(inode, oldsize, newsize); |
1009 | out_brelse: |
1010 | brelse(dibh); |
1011 | out: |
1012 | gfs2_trans_end(sdp); |
1013 | return error; |
1014 | } |
1015 | |
1016 | static int trunc_dealloc(struct gfs2_inode *ip, u64 size) |
1017 | { |
1018 | struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); |
1019 | unsigned int height = ip->i_height; |
1020 | u64 lblock; |
1021 | struct metapath mp; |
1022 | int error; |
1023 | |
1024 | if (!size) |
1025 | lblock = 0; |
1026 | else |
1027 | lblock = (size - 1) >> sdp->sd_sb.sb_bsize_shift; |
1028 | |
1029 | find_metapath(sdp, lblock, &mp, ip->i_height); |
1030 | if (!gfs2_alloc_get(ip)) |
1031 | return -ENOMEM; |
1032 | |
1033 | error = gfs2_quota_hold(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE); |
1034 | if (error) |
1035 | goto out; |
1036 | |
1037 | while (height--) { |
1038 | struct strip_mine sm; |
1039 | sm.sm_first = !!size; |
1040 | sm.sm_height = height; |
1041 | |
1042 | error = recursive_scan(ip, NULL, &mp, 0, 0, 1, do_strip, &sm); |
1043 | if (error) |
1044 | break; |
1045 | } |
1046 | |
1047 | gfs2_quota_unhold(ip); |
1048 | |
1049 | out: |
1050 | gfs2_alloc_put(ip); |
1051 | return error; |
1052 | } |
1053 | |
1054 | static int trunc_end(struct gfs2_inode *ip) |
1055 | { |
1056 | struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); |
1057 | struct buffer_head *dibh; |
1058 | int error; |
1059 | |
1060 | error = gfs2_trans_begin(sdp, RES_DINODE, 0); |
1061 | if (error) |
1062 | return error; |
1063 | |
1064 | down_write(&ip->i_rw_mutex); |
1065 | |
1066 | error = gfs2_meta_inode_buffer(ip, &dibh); |
1067 | if (error) |
1068 | goto out; |
1069 | |
1070 | if (!i_size_read(&ip->i_inode)) { |
1071 | ip->i_height = 0; |
1072 | ip->i_goal = ip->i_no_addr; |
1073 | gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode)); |
1074 | } |
1075 | ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME; |
1076 | ip->i_diskflags &= ~GFS2_DIF_TRUNC_IN_PROG; |
1077 | |
1078 | gfs2_trans_add_bh(ip->i_gl, dibh, 1); |
1079 | gfs2_dinode_out(ip, dibh->b_data); |
1080 | brelse(dibh); |
1081 | |
1082 | out: |
1083 | up_write(&ip->i_rw_mutex); |
1084 | gfs2_trans_end(sdp); |
1085 | return error; |
1086 | } |
1087 | |
1088 | /** |
1089 | * do_shrink - make a file smaller |
1090 | * @inode: the inode |
1091 | * @oldsize: the current inode size |
1092 | * @newsize: the size to make the file |
1093 | * |
1094 | * Called with an exclusive lock on @inode. The @size must |
1095 | * be equal to or smaller than the current inode size. |
1096 | * |
1097 | * Returns: errno |
1098 | */ |
1099 | |
1100 | static int do_shrink(struct inode *inode, u64 oldsize, u64 newsize) |
1101 | { |
1102 | struct gfs2_inode *ip = GFS2_I(inode); |
1103 | int error; |
1104 | |
1105 | error = trunc_start(inode, oldsize, newsize); |
1106 | if (error < 0) |
1107 | return error; |
1108 | if (gfs2_is_stuffed(ip)) |
1109 | return 0; |
1110 | |
1111 | error = trunc_dealloc(ip, newsize); |
1112 | if (error == 0) |
1113 | error = trunc_end(ip); |
1114 | |
1115 | return error; |
1116 | } |
1117 | |
1118 | void gfs2_trim_blocks(struct inode *inode) |
1119 | { |
1120 | u64 size = inode->i_size; |
1121 | int ret; |
1122 | |
1123 | ret = do_shrink(inode, size, size); |
1124 | WARN_ON(ret != 0); |
1125 | } |
1126 | |
1127 | /** |
1128 | * do_grow - Touch and update inode size |
1129 | * @inode: The inode |
1130 | * @size: The new size |
1131 | * |
1132 | * This function updates the timestamps on the inode and |
1133 | * may also increase the size of the inode. This function |
1134 | * must not be called with @size any smaller than the current |
1135 | * inode size. |
1136 | * |
1137 | * Although it is not strictly required to unstuff files here, |
1138 | * earlier versions of GFS2 have a bug in the stuffed file reading |
1139 | * code which will result in a buffer overrun if the size is larger |
1140 | * than the max stuffed file size. In order to prevent this from |
1141 | * occurring, such files are unstuffed, but in other cases we can |
1142 | * just update the inode size directly. |
1143 | * |
1144 | * Returns: 0 on success, or -ve on error |
1145 | */ |
1146 | |
1147 | static int do_grow(struct inode *inode, u64 size) |
1148 | { |
1149 | struct gfs2_inode *ip = GFS2_I(inode); |
1150 | struct gfs2_sbd *sdp = GFS2_SB(inode); |
1151 | struct buffer_head *dibh; |
1152 | struct gfs2_alloc *al = NULL; |
1153 | int error; |
1154 | |
1155 | if (gfs2_is_stuffed(ip) && |
1156 | (size > (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)))) { |
1157 | al = gfs2_alloc_get(ip); |
1158 | if (al == NULL) |
1159 | return -ENOMEM; |
1160 | |
1161 | error = gfs2_quota_lock_check(ip); |
1162 | if (error) |
1163 | goto do_grow_alloc_put; |
1164 | |
1165 | al->al_requested = 1; |
1166 | error = gfs2_inplace_reserve(ip); |
1167 | if (error) |
1168 | goto do_grow_qunlock; |
1169 | } |
1170 | |
1171 | error = gfs2_trans_begin(sdp, RES_DINODE + RES_STATFS + RES_RG_BIT, 0); |
1172 | if (error) |
1173 | goto do_grow_release; |
1174 | |
1175 | if (al) { |
1176 | error = gfs2_unstuff_dinode(ip, NULL); |
1177 | if (error) |
1178 | goto do_end_trans; |
1179 | } |
1180 | |
1181 | error = gfs2_meta_inode_buffer(ip, &dibh); |
1182 | if (error) |
1183 | goto do_end_trans; |
1184 | |
1185 | i_size_write(inode, size); |
1186 | ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME; |
1187 | gfs2_trans_add_bh(ip->i_gl, dibh, 1); |
1188 | gfs2_dinode_out(ip, dibh->b_data); |
1189 | brelse(dibh); |
1190 | |
1191 | do_end_trans: |
1192 | gfs2_trans_end(sdp); |
1193 | do_grow_release: |
1194 | if (al) { |
1195 | gfs2_inplace_release(ip); |
1196 | do_grow_qunlock: |
1197 | gfs2_quota_unlock(ip); |
1198 | do_grow_alloc_put: |
1199 | gfs2_alloc_put(ip); |
1200 | } |
1201 | return error; |
1202 | } |
1203 | |
1204 | /** |
1205 | * gfs2_setattr_size - make a file a given size |
1206 | * @inode: the inode |
1207 | * @newsize: the size to make the file |
1208 | * |
1209 | * The file size can grow, shrink, or stay the same size. This |
1210 | * is called holding i_mutex and an exclusive glock on the inode |
1211 | * in question. |
1212 | * |
1213 | * Returns: errno |
1214 | */ |
1215 | |
1216 | int gfs2_setattr_size(struct inode *inode, u64 newsize) |
1217 | { |
1218 | int ret; |
1219 | u64 oldsize; |
1220 | |
1221 | BUG_ON(!S_ISREG(inode->i_mode)); |
1222 | |
1223 | ret = inode_newsize_ok(inode, newsize); |
1224 | if (ret) |
1225 | return ret; |
1226 | |
1227 | oldsize = inode->i_size; |
1228 | if (newsize >= oldsize) |
1229 | return do_grow(inode, newsize); |
1230 | |
1231 | return do_shrink(inode, oldsize, newsize); |
1232 | } |
1233 | |
1234 | int gfs2_truncatei_resume(struct gfs2_inode *ip) |
1235 | { |
1236 | int error; |
1237 | error = trunc_dealloc(ip, i_size_read(&ip->i_inode)); |
1238 | if (!error) |
1239 | error = trunc_end(ip); |
1240 | return error; |
1241 | } |
1242 | |
1243 | int gfs2_file_dealloc(struct gfs2_inode *ip) |
1244 | { |
1245 | return trunc_dealloc(ip, 0); |
1246 | } |
1247 | |
1248 | /** |
1249 | * gfs2_write_alloc_required - figure out if a write will require an allocation |
1250 | * @ip: the file being written to |
1251 | * @offset: the offset to write to |
1252 | * @len: the number of bytes being written |
1253 | * |
1254 | * Returns: 1 if an alloc is required, 0 otherwise |
1255 | */ |
1256 | |
1257 | int gfs2_write_alloc_required(struct gfs2_inode *ip, u64 offset, |
1258 | unsigned int len) |
1259 | { |
1260 | struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); |
1261 | struct buffer_head bh; |
1262 | unsigned int shift; |
1263 | u64 lblock, lblock_stop, size; |
1264 | u64 end_of_file; |
1265 | |
1266 | if (!len) |
1267 | return 0; |
1268 | |
1269 | if (gfs2_is_stuffed(ip)) { |
1270 | if (offset + len > |
1271 | sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) |
1272 | return 1; |
1273 | return 0; |
1274 | } |
1275 | |
1276 | shift = sdp->sd_sb.sb_bsize_shift; |
1277 | BUG_ON(gfs2_is_dir(ip)); |
1278 | end_of_file = (i_size_read(&ip->i_inode) + sdp->sd_sb.sb_bsize - 1) >> shift; |
1279 | lblock = offset >> shift; |
1280 | lblock_stop = (offset + len + sdp->sd_sb.sb_bsize - 1) >> shift; |
1281 | if (lblock_stop > end_of_file) |
1282 | return 1; |
1283 | |
1284 | size = (lblock_stop - lblock) << shift; |
1285 | do { |
1286 | bh.b_state = 0; |
1287 | bh.b_size = size; |
1288 | gfs2_block_map(&ip->i_inode, lblock, &bh, 0); |
1289 | if (!buffer_mapped(&bh)) |
1290 | return 1; |
1291 | size -= bh.b_size; |
1292 | lblock += (bh.b_size >> ip->i_inode.i_blkbits); |
1293 | } while(size > 0); |
1294 | |
1295 | return 0; |
1296 | } |
1297 | |
1298 |
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od-2011-09-18
v2.6.34-rc5
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