PM / yenta: Split resume into early and late parts (rev. 4)
[linux/fpc-iii.git] / fs / gfs2 / bmap.c
blob6d47379e794bc4a6b8a9f665aa3546da36dde441
1 /*
2 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
3 * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
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 */
10 #include <linux/slab.h>
11 #include <linux/spinlock.h>
12 #include <linux/completion.h>
13 #include <linux/buffer_head.h>
14 #include <linux/gfs2_ondisk.h>
15 #include <linux/crc32.h>
17 #include "gfs2.h"
18 #include "incore.h"
19 #include "bmap.h"
20 #include "glock.h"
21 #include "inode.h"
22 #include "meta_io.h"
23 #include "quota.h"
24 #include "rgrp.h"
25 #include "trans.h"
26 #include "dir.h"
27 #include "util.h"
28 #include "trace_gfs2.h"
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.
34 struct metapath {
35 struct buffer_head *mp_bh[GFS2_MAX_META_HEIGHT];
36 __u16 mp_list[GFS2_MAX_META_HEIGHT];
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);
44 struct strip_mine {
45 int sm_first;
46 unsigned int sm_height;
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 * @private: any locked page held by the caller process
56 * Returns: errno
59 static int gfs2_unstuffer_page(struct gfs2_inode *ip, struct buffer_head *dibh,
60 u64 block, struct page *page)
62 struct inode *inode = &ip->i_inode;
63 struct buffer_head *bh;
64 int release = 0;
66 if (!page || page->index) {
67 page = grab_cache_page(inode->i_mapping, 0);
68 if (!page)
69 return -ENOMEM;
70 release = 1;
73 if (!PageUptodate(page)) {
74 void *kaddr = kmap(page);
76 memcpy(kaddr, dibh->b_data + sizeof(struct gfs2_dinode),
77 ip->i_disksize);
78 memset(kaddr + ip->i_disksize, 0,
79 PAGE_CACHE_SIZE - ip->i_disksize);
80 kunmap(page);
82 SetPageUptodate(page);
85 if (!page_has_buffers(page))
86 create_empty_buffers(page, 1 << inode->i_blkbits,
87 (1 << BH_Uptodate));
89 bh = page_buffers(page);
91 if (!buffer_mapped(bh))
92 map_bh(bh, inode->i_sb, block);
94 set_buffer_uptodate(bh);
95 if (!gfs2_is_jdata(ip))
96 mark_buffer_dirty(bh);
97 if (!gfs2_is_writeback(ip))
98 gfs2_trans_add_bh(ip->i_gl, bh, 0);
100 if (release) {
101 unlock_page(page);
102 page_cache_release(page);
105 return 0;
109 * gfs2_unstuff_dinode - Unstuff a dinode when the data has grown too big
110 * @ip: The GFS2 inode to unstuff
111 * @unstuffer: the routine that handles unstuffing a non-zero length file
112 * @private: private data for the unstuffer
114 * This routine unstuffs a dinode and returns it to a "normal" state such
115 * that the height can be grown in the traditional way.
117 * Returns: errno
120 int gfs2_unstuff_dinode(struct gfs2_inode *ip, struct page *page)
122 struct buffer_head *bh, *dibh;
123 struct gfs2_dinode *di;
124 u64 block = 0;
125 int isdir = gfs2_is_dir(ip);
126 int error;
128 down_write(&ip->i_rw_mutex);
130 error = gfs2_meta_inode_buffer(ip, &dibh);
131 if (error)
132 goto out;
134 if (ip->i_disksize) {
135 /* Get a free block, fill it with the stuffed data,
136 and write it out to disk */
138 unsigned int n = 1;
139 error = gfs2_alloc_block(ip, &block, &n);
140 if (error)
141 goto out_brelse;
142 if (isdir) {
143 gfs2_trans_add_unrevoke(GFS2_SB(&ip->i_inode), block, 1);
144 error = gfs2_dir_get_new_buffer(ip, block, &bh);
145 if (error)
146 goto out_brelse;
147 gfs2_buffer_copy_tail(bh, sizeof(struct gfs2_meta_header),
148 dibh, sizeof(struct gfs2_dinode));
149 brelse(bh);
150 } else {
151 error = gfs2_unstuffer_page(ip, dibh, block, page);
152 if (error)
153 goto out_brelse;
157 /* Set up the pointer to the new block */
159 gfs2_trans_add_bh(ip->i_gl, dibh, 1);
160 di = (struct gfs2_dinode *)dibh->b_data;
161 gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode));
163 if (ip->i_disksize) {
164 *(__be64 *)(di + 1) = cpu_to_be64(block);
165 gfs2_add_inode_blocks(&ip->i_inode, 1);
166 di->di_blocks = cpu_to_be64(gfs2_get_inode_blocks(&ip->i_inode));
169 ip->i_height = 1;
170 di->di_height = cpu_to_be16(1);
172 out_brelse:
173 brelse(dibh);
174 out:
175 up_write(&ip->i_rw_mutex);
176 return error;
181 * find_metapath - Find path through the metadata tree
182 * @sdp: The superblock
183 * @mp: The metapath to return the result in
184 * @block: The disk block to look up
185 * @height: The pre-calculated height of the metadata tree
187 * This routine returns a struct metapath structure that defines a path
188 * through the metadata of inode "ip" to get to block "block".
190 * Example:
191 * Given: "ip" is a height 3 file, "offset" is 101342453, and this is a
192 * filesystem with a blocksize of 4096.
194 * find_metapath() would return a struct metapath structure set to:
195 * mp_offset = 101342453, mp_height = 3, mp_list[0] = 0, mp_list[1] = 48,
196 * and mp_list[2] = 165.
198 * That means that in order to get to the block containing the byte at
199 * offset 101342453, we would load the indirect block pointed to by pointer
200 * 0 in the dinode. We would then load the indirect block pointed to by
201 * pointer 48 in that indirect block. We would then load the data block
202 * pointed to by pointer 165 in that indirect block.
204 * ----------------------------------------
205 * | Dinode | |
206 * | | 4|
207 * | |0 1 2 3 4 5 9|
208 * | | 6|
209 * ----------------------------------------
213 * ----------------------------------------
214 * | Indirect Block |
215 * | 5|
216 * | 4 4 4 4 4 5 5 1|
217 * |0 5 6 7 8 9 0 1 2|
218 * ----------------------------------------
222 * ----------------------------------------
223 * | Indirect Block |
224 * | 1 1 1 1 1 5|
225 * | 6 6 6 6 6 1|
226 * |0 3 4 5 6 7 2|
227 * ----------------------------------------
231 * ----------------------------------------
232 * | Data block containing offset |
233 * | 101342453 |
234 * | |
235 * | |
236 * ----------------------------------------
240 static void find_metapath(const struct gfs2_sbd *sdp, u64 block,
241 struct metapath *mp, unsigned int height)
243 unsigned int i;
245 for (i = height; i--;)
246 mp->mp_list[i] = do_div(block, sdp->sd_inptrs);
250 static inline unsigned int metapath_branch_start(const struct metapath *mp)
252 if (mp->mp_list[0] == 0)
253 return 2;
254 return 1;
258 * metapointer - Return pointer to start of metadata in a buffer
259 * @height: The metadata height (0 = dinode)
260 * @mp: The metapath
262 * Return a pointer to the block number of the next height of the metadata
263 * tree given a buffer containing the pointer to the current height of the
264 * metadata tree.
267 static inline __be64 *metapointer(unsigned int height, const struct metapath *mp)
269 struct buffer_head *bh = mp->mp_bh[height];
270 unsigned int head_size = (height > 0) ?
271 sizeof(struct gfs2_meta_header) : sizeof(struct gfs2_dinode);
272 return ((__be64 *)(bh->b_data + head_size)) + mp->mp_list[height];
276 * lookup_metapath - Walk the metadata tree to a specific point
277 * @ip: The inode
278 * @mp: The metapath
280 * Assumes that the inode's buffer has already been looked up and
281 * hooked onto mp->mp_bh[0] and that the metapath has been initialised
282 * by find_metapath().
284 * If this function encounters part of the tree which has not been
285 * allocated, it returns the current height of the tree at the point
286 * at which it found the unallocated block. Blocks which are found are
287 * added to the mp->mp_bh[] list.
289 * Returns: error or height of metadata tree
292 static int lookup_metapath(struct gfs2_inode *ip, struct metapath *mp)
294 unsigned int end_of_metadata = ip->i_height - 1;
295 unsigned int x;
296 __be64 *ptr;
297 u64 dblock;
298 int ret;
300 for (x = 0; x < end_of_metadata; x++) {
301 ptr = metapointer(x, mp);
302 dblock = be64_to_cpu(*ptr);
303 if (!dblock)
304 return x + 1;
306 ret = gfs2_meta_indirect_buffer(ip, x+1, dblock, 0, &mp->mp_bh[x+1]);
307 if (ret)
308 return ret;
311 return ip->i_height;
314 static inline void release_metapath(struct metapath *mp)
316 int i;
318 for (i = 0; i < GFS2_MAX_META_HEIGHT; i++) {
319 if (mp->mp_bh[i] == NULL)
320 break;
321 brelse(mp->mp_bh[i]);
326 * gfs2_extent_length - Returns length of an extent of blocks
327 * @start: Start of the buffer
328 * @len: Length of the buffer in bytes
329 * @ptr: Current position in the buffer
330 * @limit: Max extent length to return (0 = unlimited)
331 * @eob: Set to 1 if we hit "end of block"
333 * If the first block is zero (unallocated) it will return the number of
334 * unallocated blocks in the extent, otherwise it will return the number
335 * of contiguous blocks in the extent.
337 * Returns: The length of the extent (minimum of one block)
340 static inline unsigned int gfs2_extent_length(void *start, unsigned int len, __be64 *ptr, unsigned limit, int *eob)
342 const __be64 *end = (start + len);
343 const __be64 *first = ptr;
344 u64 d = be64_to_cpu(*ptr);
346 *eob = 0;
347 do {
348 ptr++;
349 if (ptr >= end)
350 break;
351 if (limit && --limit == 0)
352 break;
353 if (d)
354 d++;
355 } while(be64_to_cpu(*ptr) == d);
356 if (ptr >= end)
357 *eob = 1;
358 return (ptr - first);
361 static inline void bmap_lock(struct gfs2_inode *ip, int create)
363 if (create)
364 down_write(&ip->i_rw_mutex);
365 else
366 down_read(&ip->i_rw_mutex);
369 static inline void bmap_unlock(struct gfs2_inode *ip, int create)
371 if (create)
372 up_write(&ip->i_rw_mutex);
373 else
374 up_read(&ip->i_rw_mutex);
377 static inline __be64 *gfs2_indirect_init(struct metapath *mp,
378 struct gfs2_glock *gl, unsigned int i,
379 unsigned offset, u64 bn)
381 __be64 *ptr = (__be64 *)(mp->mp_bh[i - 1]->b_data +
382 ((i > 1) ? sizeof(struct gfs2_meta_header) :
383 sizeof(struct gfs2_dinode)));
384 BUG_ON(i < 1);
385 BUG_ON(mp->mp_bh[i] != NULL);
386 mp->mp_bh[i] = gfs2_meta_new(gl, bn);
387 gfs2_trans_add_bh(gl, mp->mp_bh[i], 1);
388 gfs2_metatype_set(mp->mp_bh[i], GFS2_METATYPE_IN, GFS2_FORMAT_IN);
389 gfs2_buffer_clear_tail(mp->mp_bh[i], sizeof(struct gfs2_meta_header));
390 ptr += offset;
391 *ptr = cpu_to_be64(bn);
392 return ptr;
395 enum alloc_state {
396 ALLOC_DATA = 0,
397 ALLOC_GROW_DEPTH = 1,
398 ALLOC_GROW_HEIGHT = 2,
399 /* ALLOC_UNSTUFF = 3, TBD and rather complicated */
403 * gfs2_bmap_alloc - Build a metadata tree of the requested height
404 * @inode: The GFS2 inode
405 * @lblock: The logical starting block of the extent
406 * @bh_map: This is used to return the mapping details
407 * @mp: The metapath
408 * @sheight: The starting height (i.e. whats already mapped)
409 * @height: The height to build to
410 * @maxlen: The max number of data blocks to alloc
412 * In this routine we may have to alloc:
413 * i) Indirect blocks to grow the metadata tree height
414 * ii) Indirect blocks to fill in lower part of the metadata tree
415 * iii) Data blocks
417 * The function is in two parts. The first part works out the total
418 * number of blocks which we need. The second part does the actual
419 * allocation asking for an extent at a time (if enough contiguous free
420 * blocks are available, there will only be one request per bmap call)
421 * and uses the state machine to initialise the blocks in order.
423 * Returns: errno on error
426 static int gfs2_bmap_alloc(struct inode *inode, const sector_t lblock,
427 struct buffer_head *bh_map, struct metapath *mp,
428 const unsigned int sheight,
429 const unsigned int height,
430 const unsigned int maxlen)
432 struct gfs2_inode *ip = GFS2_I(inode);
433 struct gfs2_sbd *sdp = GFS2_SB(inode);
434 struct buffer_head *dibh = mp->mp_bh[0];
435 u64 bn, dblock = 0;
436 unsigned n, i, blks, alloced = 0, iblks = 0, branch_start = 0;
437 unsigned dblks = 0;
438 unsigned ptrs_per_blk;
439 const unsigned end_of_metadata = height - 1;
440 int eob = 0;
441 enum alloc_state state;
442 __be64 *ptr;
443 __be64 zero_bn = 0;
445 BUG_ON(sheight < 1);
446 BUG_ON(dibh == NULL);
448 gfs2_trans_add_bh(ip->i_gl, dibh, 1);
450 if (height == sheight) {
451 struct buffer_head *bh;
452 /* Bottom indirect block exists, find unalloced extent size */
453 ptr = metapointer(end_of_metadata, mp);
454 bh = mp->mp_bh[end_of_metadata];
455 dblks = gfs2_extent_length(bh->b_data, bh->b_size, ptr, maxlen,
456 &eob);
457 BUG_ON(dblks < 1);
458 state = ALLOC_DATA;
459 } else {
460 /* Need to allocate indirect blocks */
461 ptrs_per_blk = height > 1 ? sdp->sd_inptrs : sdp->sd_diptrs;
462 dblks = min(maxlen, ptrs_per_blk - mp->mp_list[end_of_metadata]);
463 if (height == ip->i_height) {
464 /* Writing into existing tree, extend tree down */
465 iblks = height - sheight;
466 state = ALLOC_GROW_DEPTH;
467 } else {
468 /* Building up tree height */
469 state = ALLOC_GROW_HEIGHT;
470 iblks = height - ip->i_height;
471 branch_start = metapath_branch_start(mp);
472 iblks += (height - branch_start);
476 /* start of the second part of the function (state machine) */
478 blks = dblks + iblks;
479 i = sheight;
480 do {
481 int error;
482 n = blks - alloced;
483 error = gfs2_alloc_block(ip, &bn, &n);
484 if (error)
485 return error;
486 alloced += n;
487 if (state != ALLOC_DATA || gfs2_is_jdata(ip))
488 gfs2_trans_add_unrevoke(sdp, bn, n);
489 switch (state) {
490 /* Growing height of tree */
491 case ALLOC_GROW_HEIGHT:
492 if (i == 1) {
493 ptr = (__be64 *)(dibh->b_data +
494 sizeof(struct gfs2_dinode));
495 zero_bn = *ptr;
497 for (; i - 1 < height - ip->i_height && n > 0; i++, n--)
498 gfs2_indirect_init(mp, ip->i_gl, i, 0, bn++);
499 if (i - 1 == height - ip->i_height) {
500 i--;
501 gfs2_buffer_copy_tail(mp->mp_bh[i],
502 sizeof(struct gfs2_meta_header),
503 dibh, sizeof(struct gfs2_dinode));
504 gfs2_buffer_clear_tail(dibh,
505 sizeof(struct gfs2_dinode) +
506 sizeof(__be64));
507 ptr = (__be64 *)(mp->mp_bh[i]->b_data +
508 sizeof(struct gfs2_meta_header));
509 *ptr = zero_bn;
510 state = ALLOC_GROW_DEPTH;
511 for(i = branch_start; i < height; i++) {
512 if (mp->mp_bh[i] == NULL)
513 break;
514 brelse(mp->mp_bh[i]);
515 mp->mp_bh[i] = NULL;
517 i = branch_start;
519 if (n == 0)
520 break;
521 /* Branching from existing tree */
522 case ALLOC_GROW_DEPTH:
523 if (i > 1 && i < height)
524 gfs2_trans_add_bh(ip->i_gl, mp->mp_bh[i-1], 1);
525 for (; i < height && n > 0; i++, n--)
526 gfs2_indirect_init(mp, ip->i_gl, i,
527 mp->mp_list[i-1], bn++);
528 if (i == height)
529 state = ALLOC_DATA;
530 if (n == 0)
531 break;
532 /* Tree complete, adding data blocks */
533 case ALLOC_DATA:
534 BUG_ON(n > dblks);
535 BUG_ON(mp->mp_bh[end_of_metadata] == NULL);
536 gfs2_trans_add_bh(ip->i_gl, mp->mp_bh[end_of_metadata], 1);
537 dblks = n;
538 ptr = metapointer(end_of_metadata, mp);
539 dblock = bn;
540 while (n-- > 0)
541 *ptr++ = cpu_to_be64(bn++);
542 break;
544 } while (state != ALLOC_DATA);
546 ip->i_height = height;
547 gfs2_add_inode_blocks(&ip->i_inode, alloced);
548 gfs2_dinode_out(ip, mp->mp_bh[0]->b_data);
549 map_bh(bh_map, inode->i_sb, dblock);
550 bh_map->b_size = dblks << inode->i_blkbits;
551 set_buffer_new(bh_map);
552 return 0;
556 * gfs2_block_map - Map a block from an inode to a disk block
557 * @inode: The inode
558 * @lblock: The logical block number
559 * @bh_map: The bh to be mapped
560 * @create: True if its ok to alloc blocks to satify the request
562 * Sets buffer_mapped() if successful, sets buffer_boundary() if a
563 * read of metadata will be required before the next block can be
564 * mapped. Sets buffer_new() if new blocks were allocated.
566 * Returns: errno
569 int gfs2_block_map(struct inode *inode, sector_t lblock,
570 struct buffer_head *bh_map, int create)
572 struct gfs2_inode *ip = GFS2_I(inode);
573 struct gfs2_sbd *sdp = GFS2_SB(inode);
574 unsigned int bsize = sdp->sd_sb.sb_bsize;
575 const unsigned int maxlen = bh_map->b_size >> inode->i_blkbits;
576 const u64 *arr = sdp->sd_heightsize;
577 __be64 *ptr;
578 u64 size;
579 struct metapath mp;
580 int ret;
581 int eob;
582 unsigned int len;
583 struct buffer_head *bh;
584 u8 height;
586 BUG_ON(maxlen == 0);
588 memset(mp.mp_bh, 0, sizeof(mp.mp_bh));
589 bmap_lock(ip, create);
590 clear_buffer_mapped(bh_map);
591 clear_buffer_new(bh_map);
592 clear_buffer_boundary(bh_map);
593 trace_gfs2_bmap(ip, bh_map, lblock, create, 1);
594 if (gfs2_is_dir(ip)) {
595 bsize = sdp->sd_jbsize;
596 arr = sdp->sd_jheightsize;
599 ret = gfs2_meta_inode_buffer(ip, &mp.mp_bh[0]);
600 if (ret)
601 goto out;
603 height = ip->i_height;
604 size = (lblock + 1) * bsize;
605 while (size > arr[height])
606 height++;
607 find_metapath(sdp, lblock, &mp, height);
608 ret = 1;
609 if (height > ip->i_height || gfs2_is_stuffed(ip))
610 goto do_alloc;
611 ret = lookup_metapath(ip, &mp);
612 if (ret < 0)
613 goto out;
614 if (ret != ip->i_height)
615 goto do_alloc;
616 ptr = metapointer(ip->i_height - 1, &mp);
617 if (*ptr == 0)
618 goto do_alloc;
619 map_bh(bh_map, inode->i_sb, be64_to_cpu(*ptr));
620 bh = mp.mp_bh[ip->i_height - 1];
621 len = gfs2_extent_length(bh->b_data, bh->b_size, ptr, maxlen, &eob);
622 bh_map->b_size = (len << inode->i_blkbits);
623 if (eob)
624 set_buffer_boundary(bh_map);
625 ret = 0;
626 out:
627 release_metapath(&mp);
628 trace_gfs2_bmap(ip, bh_map, lblock, create, ret);
629 bmap_unlock(ip, create);
630 return ret;
632 do_alloc:
633 /* All allocations are done here, firstly check create flag */
634 if (!create) {
635 BUG_ON(gfs2_is_stuffed(ip));
636 ret = 0;
637 goto out;
640 /* At this point ret is the tree depth of already allocated blocks */
641 ret = gfs2_bmap_alloc(inode, lblock, bh_map, &mp, ret, height, maxlen);
642 goto out;
646 * Deprecated: do not use in new code
648 int gfs2_extent_map(struct inode *inode, u64 lblock, int *new, u64 *dblock, unsigned *extlen)
650 struct buffer_head bh = { .b_state = 0, .b_blocknr = 0 };
651 int ret;
652 int create = *new;
654 BUG_ON(!extlen);
655 BUG_ON(!dblock);
656 BUG_ON(!new);
658 bh.b_size = 1 << (inode->i_blkbits + (create ? 0 : 5));
659 ret = gfs2_block_map(inode, lblock, &bh, create);
660 *extlen = bh.b_size >> inode->i_blkbits;
661 *dblock = bh.b_blocknr;
662 if (buffer_new(&bh))
663 *new = 1;
664 else
665 *new = 0;
666 return ret;
670 * recursive_scan - recursively scan through the end of a file
671 * @ip: the inode
672 * @dibh: the dinode buffer
673 * @mp: the path through the metadata to the point to start
674 * @height: the height the recursion is at
675 * @block: the indirect block to look at
676 * @first: 1 if this is the first block
677 * @bc: the call to make for each piece of metadata
678 * @data: data opaque to this function to pass to @bc
680 * When this is first called @height and @block should be zero and
681 * @first should be 1.
683 * Returns: errno
686 static int recursive_scan(struct gfs2_inode *ip, struct buffer_head *dibh,
687 struct metapath *mp, unsigned int height,
688 u64 block, int first, block_call_t bc,
689 void *data)
691 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
692 struct buffer_head *bh = NULL;
693 __be64 *top, *bottom;
694 u64 bn;
695 int error;
696 int mh_size = sizeof(struct gfs2_meta_header);
698 if (!height) {
699 error = gfs2_meta_inode_buffer(ip, &bh);
700 if (error)
701 return error;
702 dibh = bh;
704 top = (__be64 *)(bh->b_data + sizeof(struct gfs2_dinode)) + mp->mp_list[0];
705 bottom = (__be64 *)(bh->b_data + sizeof(struct gfs2_dinode)) + sdp->sd_diptrs;
706 } else {
707 error = gfs2_meta_indirect_buffer(ip, height, block, 0, &bh);
708 if (error)
709 return error;
711 top = (__be64 *)(bh->b_data + mh_size) +
712 (first ? mp->mp_list[height] : 0);
714 bottom = (__be64 *)(bh->b_data + mh_size) + sdp->sd_inptrs;
717 error = bc(ip, dibh, bh, top, bottom, height, data);
718 if (error)
719 goto out;
721 if (height < ip->i_height - 1)
722 for (; top < bottom; top++, first = 0) {
723 if (!*top)
724 continue;
726 bn = be64_to_cpu(*top);
728 error = recursive_scan(ip, dibh, mp, height + 1, bn,
729 first, bc, data);
730 if (error)
731 break;
734 out:
735 brelse(bh);
736 return error;
740 * do_strip - Look for a layer a particular layer of the file and strip it off
741 * @ip: the inode
742 * @dibh: the dinode buffer
743 * @bh: A buffer of pointers
744 * @top: The first pointer in the buffer
745 * @bottom: One more than the last pointer
746 * @height: the height this buffer is at
747 * @data: a pointer to a struct strip_mine
749 * Returns: errno
752 static int do_strip(struct gfs2_inode *ip, struct buffer_head *dibh,
753 struct buffer_head *bh, __be64 *top, __be64 *bottom,
754 unsigned int height, void *data)
756 struct strip_mine *sm = data;
757 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
758 struct gfs2_rgrp_list rlist;
759 u64 bn, bstart;
760 u32 blen;
761 __be64 *p;
762 unsigned int rg_blocks = 0;
763 int metadata;
764 unsigned int revokes = 0;
765 int x;
766 int error;
768 if (!*top)
769 sm->sm_first = 0;
771 if (height != sm->sm_height)
772 return 0;
774 if (sm->sm_first) {
775 top++;
776 sm->sm_first = 0;
779 metadata = (height != ip->i_height - 1);
780 if (metadata)
781 revokes = (height) ? sdp->sd_inptrs : sdp->sd_diptrs;
783 error = gfs2_rindex_hold(sdp, &ip->i_alloc->al_ri_gh);
784 if (error)
785 return error;
787 memset(&rlist, 0, sizeof(struct gfs2_rgrp_list));
788 bstart = 0;
789 blen = 0;
791 for (p = top; p < bottom; p++) {
792 if (!*p)
793 continue;
795 bn = be64_to_cpu(*p);
797 if (bstart + blen == bn)
798 blen++;
799 else {
800 if (bstart)
801 gfs2_rlist_add(sdp, &rlist, bstart);
803 bstart = bn;
804 blen = 1;
808 if (bstart)
809 gfs2_rlist_add(sdp, &rlist, bstart);
810 else
811 goto out; /* Nothing to do */
813 gfs2_rlist_alloc(&rlist, LM_ST_EXCLUSIVE);
815 for (x = 0; x < rlist.rl_rgrps; x++) {
816 struct gfs2_rgrpd *rgd;
817 rgd = rlist.rl_ghs[x].gh_gl->gl_object;
818 rg_blocks += rgd->rd_length;
821 error = gfs2_glock_nq_m(rlist.rl_rgrps, rlist.rl_ghs);
822 if (error)
823 goto out_rlist;
825 error = gfs2_trans_begin(sdp, rg_blocks + RES_DINODE +
826 RES_INDIRECT + RES_STATFS + RES_QUOTA,
827 revokes);
828 if (error)
829 goto out_rg_gunlock;
831 down_write(&ip->i_rw_mutex);
833 gfs2_trans_add_bh(ip->i_gl, dibh, 1);
834 gfs2_trans_add_bh(ip->i_gl, bh, 1);
836 bstart = 0;
837 blen = 0;
839 for (p = top; p < bottom; p++) {
840 if (!*p)
841 continue;
843 bn = be64_to_cpu(*p);
845 if (bstart + blen == bn)
846 blen++;
847 else {
848 if (bstart) {
849 if (metadata)
850 gfs2_free_meta(ip, bstart, blen);
851 else
852 gfs2_free_data(ip, bstart, blen);
855 bstart = bn;
856 blen = 1;
859 *p = 0;
860 gfs2_add_inode_blocks(&ip->i_inode, -1);
862 if (bstart) {
863 if (metadata)
864 gfs2_free_meta(ip, bstart, blen);
865 else
866 gfs2_free_data(ip, bstart, blen);
869 ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
871 gfs2_dinode_out(ip, dibh->b_data);
873 up_write(&ip->i_rw_mutex);
875 gfs2_trans_end(sdp);
877 out_rg_gunlock:
878 gfs2_glock_dq_m(rlist.rl_rgrps, rlist.rl_ghs);
879 out_rlist:
880 gfs2_rlist_free(&rlist);
881 out:
882 gfs2_glock_dq_uninit(&ip->i_alloc->al_ri_gh);
883 return error;
887 * do_grow - Make a file look bigger than it is
888 * @ip: the inode
889 * @size: the size to set the file to
891 * Called with an exclusive lock on @ip.
893 * Returns: errno
896 static int do_grow(struct gfs2_inode *ip, u64 size)
898 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
899 struct gfs2_alloc *al;
900 struct buffer_head *dibh;
901 int error;
903 al = gfs2_alloc_get(ip);
904 if (!al)
905 return -ENOMEM;
907 error = gfs2_quota_lock_check(ip);
908 if (error)
909 goto out;
911 al->al_requested = sdp->sd_max_height + RES_DATA;
913 error = gfs2_inplace_reserve(ip);
914 if (error)
915 goto out_gunlock_q;
917 error = gfs2_trans_begin(sdp,
918 sdp->sd_max_height + al->al_rgd->rd_length +
919 RES_JDATA + RES_DINODE + RES_STATFS + RES_QUOTA, 0);
920 if (error)
921 goto out_ipres;
923 error = gfs2_meta_inode_buffer(ip, &dibh);
924 if (error)
925 goto out_end_trans;
927 if (size > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
928 if (gfs2_is_stuffed(ip)) {
929 error = gfs2_unstuff_dinode(ip, NULL);
930 if (error)
931 goto out_brelse;
935 ip->i_disksize = size;
936 ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
937 gfs2_trans_add_bh(ip->i_gl, dibh, 1);
938 gfs2_dinode_out(ip, dibh->b_data);
940 out_brelse:
941 brelse(dibh);
942 out_end_trans:
943 gfs2_trans_end(sdp);
944 out_ipres:
945 gfs2_inplace_release(ip);
946 out_gunlock_q:
947 gfs2_quota_unlock(ip);
948 out:
949 gfs2_alloc_put(ip);
950 return error;
955 * gfs2_block_truncate_page - Deal with zeroing out data for truncate
957 * This is partly borrowed from ext3.
959 static int gfs2_block_truncate_page(struct address_space *mapping)
961 struct inode *inode = mapping->host;
962 struct gfs2_inode *ip = GFS2_I(inode);
963 loff_t from = inode->i_size;
964 unsigned long index = from >> PAGE_CACHE_SHIFT;
965 unsigned offset = from & (PAGE_CACHE_SIZE-1);
966 unsigned blocksize, iblock, length, pos;
967 struct buffer_head *bh;
968 struct page *page;
969 int err;
971 page = grab_cache_page(mapping, index);
972 if (!page)
973 return 0;
975 blocksize = inode->i_sb->s_blocksize;
976 length = blocksize - (offset & (blocksize - 1));
977 iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
979 if (!page_has_buffers(page))
980 create_empty_buffers(page, blocksize, 0);
982 /* Find the buffer that contains "offset" */
983 bh = page_buffers(page);
984 pos = blocksize;
985 while (offset >= pos) {
986 bh = bh->b_this_page;
987 iblock++;
988 pos += blocksize;
991 err = 0;
993 if (!buffer_mapped(bh)) {
994 gfs2_block_map(inode, iblock, bh, 0);
995 /* unmapped? It's a hole - nothing to do */
996 if (!buffer_mapped(bh))
997 goto unlock;
1000 /* Ok, it's mapped. Make sure it's up-to-date */
1001 if (PageUptodate(page))
1002 set_buffer_uptodate(bh);
1004 if (!buffer_uptodate(bh)) {
1005 err = -EIO;
1006 ll_rw_block(READ, 1, &bh);
1007 wait_on_buffer(bh);
1008 /* Uhhuh. Read error. Complain and punt. */
1009 if (!buffer_uptodate(bh))
1010 goto unlock;
1011 err = 0;
1014 if (!gfs2_is_writeback(ip))
1015 gfs2_trans_add_bh(ip->i_gl, bh, 0);
1017 zero_user(page, offset, length);
1018 mark_buffer_dirty(bh);
1019 unlock:
1020 unlock_page(page);
1021 page_cache_release(page);
1022 return err;
1025 static int trunc_start(struct gfs2_inode *ip, u64 size)
1027 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
1028 struct buffer_head *dibh;
1029 int journaled = gfs2_is_jdata(ip);
1030 int error;
1032 error = gfs2_trans_begin(sdp,
1033 RES_DINODE + (journaled ? RES_JDATA : 0), 0);
1034 if (error)
1035 return error;
1037 error = gfs2_meta_inode_buffer(ip, &dibh);
1038 if (error)
1039 goto out;
1041 if (gfs2_is_stuffed(ip)) {
1042 ip->i_disksize = size;
1043 ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
1044 gfs2_trans_add_bh(ip->i_gl, dibh, 1);
1045 gfs2_dinode_out(ip, dibh->b_data);
1046 gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode) + size);
1047 error = 1;
1049 } else {
1050 if (size & (u64)(sdp->sd_sb.sb_bsize - 1))
1051 error = gfs2_block_truncate_page(ip->i_inode.i_mapping);
1053 if (!error) {
1054 ip->i_disksize = size;
1055 ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
1056 ip->i_diskflags |= GFS2_DIF_TRUNC_IN_PROG;
1057 gfs2_trans_add_bh(ip->i_gl, dibh, 1);
1058 gfs2_dinode_out(ip, dibh->b_data);
1062 brelse(dibh);
1064 out:
1065 gfs2_trans_end(sdp);
1066 return error;
1069 static int trunc_dealloc(struct gfs2_inode *ip, u64 size)
1071 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
1072 unsigned int height = ip->i_height;
1073 u64 lblock;
1074 struct metapath mp;
1075 int error;
1077 if (!size)
1078 lblock = 0;
1079 else
1080 lblock = (size - 1) >> sdp->sd_sb.sb_bsize_shift;
1082 find_metapath(sdp, lblock, &mp, ip->i_height);
1083 if (!gfs2_alloc_get(ip))
1084 return -ENOMEM;
1086 error = gfs2_quota_hold(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
1087 if (error)
1088 goto out;
1090 while (height--) {
1091 struct strip_mine sm;
1092 sm.sm_first = !!size;
1093 sm.sm_height = height;
1095 error = recursive_scan(ip, NULL, &mp, 0, 0, 1, do_strip, &sm);
1096 if (error)
1097 break;
1100 gfs2_quota_unhold(ip);
1102 out:
1103 gfs2_alloc_put(ip);
1104 return error;
1107 static int trunc_end(struct gfs2_inode *ip)
1109 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
1110 struct buffer_head *dibh;
1111 int error;
1113 error = gfs2_trans_begin(sdp, RES_DINODE, 0);
1114 if (error)
1115 return error;
1117 down_write(&ip->i_rw_mutex);
1119 error = gfs2_meta_inode_buffer(ip, &dibh);
1120 if (error)
1121 goto out;
1123 if (!ip->i_disksize) {
1124 ip->i_height = 0;
1125 ip->i_goal = ip->i_no_addr;
1126 gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode));
1128 ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
1129 ip->i_diskflags &= ~GFS2_DIF_TRUNC_IN_PROG;
1131 gfs2_trans_add_bh(ip->i_gl, dibh, 1);
1132 gfs2_dinode_out(ip, dibh->b_data);
1133 brelse(dibh);
1135 out:
1136 up_write(&ip->i_rw_mutex);
1137 gfs2_trans_end(sdp);
1138 return error;
1142 * do_shrink - make a file smaller
1143 * @ip: the inode
1144 * @size: the size to make the file
1145 * @truncator: function to truncate the last partial block
1147 * Called with an exclusive lock on @ip.
1149 * Returns: errno
1152 static int do_shrink(struct gfs2_inode *ip, u64 size)
1154 int error;
1156 error = trunc_start(ip, size);
1157 if (error < 0)
1158 return error;
1159 if (error > 0)
1160 return 0;
1162 error = trunc_dealloc(ip, size);
1163 if (!error)
1164 error = trunc_end(ip);
1166 return error;
1169 static int do_touch(struct gfs2_inode *ip, u64 size)
1171 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
1172 struct buffer_head *dibh;
1173 int error;
1175 error = gfs2_trans_begin(sdp, RES_DINODE, 0);
1176 if (error)
1177 return error;
1179 down_write(&ip->i_rw_mutex);
1181 error = gfs2_meta_inode_buffer(ip, &dibh);
1182 if (error)
1183 goto do_touch_out;
1185 ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
1186 gfs2_trans_add_bh(ip->i_gl, dibh, 1);
1187 gfs2_dinode_out(ip, dibh->b_data);
1188 brelse(dibh);
1190 do_touch_out:
1191 up_write(&ip->i_rw_mutex);
1192 gfs2_trans_end(sdp);
1193 return error;
1197 * gfs2_truncatei - make a file a given size
1198 * @ip: the inode
1199 * @size: the size to make the file
1200 * @truncator: function to truncate the last partial block
1202 * The file size can grow, shrink, or stay the same size.
1204 * Returns: errno
1207 int gfs2_truncatei(struct gfs2_inode *ip, u64 size)
1209 int error;
1211 if (gfs2_assert_warn(GFS2_SB(&ip->i_inode), S_ISREG(ip->i_inode.i_mode)))
1212 return -EINVAL;
1214 if (size > ip->i_disksize)
1215 error = do_grow(ip, size);
1216 else if (size < ip->i_disksize)
1217 error = do_shrink(ip, size);
1218 else
1219 /* update time stamps */
1220 error = do_touch(ip, size);
1222 return error;
1225 int gfs2_truncatei_resume(struct gfs2_inode *ip)
1227 int error;
1228 error = trunc_dealloc(ip, ip->i_disksize);
1229 if (!error)
1230 error = trunc_end(ip);
1231 return error;
1234 int gfs2_file_dealloc(struct gfs2_inode *ip)
1236 return trunc_dealloc(ip, 0);
1240 * gfs2_write_alloc_required - figure out if a write will require an allocation
1241 * @ip: the file being written to
1242 * @offset: the offset to write to
1243 * @len: the number of bytes being written
1244 * @alloc_required: set to 1 if an alloc is required, 0 otherwise
1246 * Returns: errno
1249 int gfs2_write_alloc_required(struct gfs2_inode *ip, u64 offset,
1250 unsigned int len, int *alloc_required)
1252 struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
1253 struct buffer_head bh;
1254 unsigned int shift;
1255 u64 lblock, lblock_stop, size;
1256 u64 end_of_file;
1258 *alloc_required = 0;
1260 if (!len)
1261 return 0;
1263 if (gfs2_is_stuffed(ip)) {
1264 if (offset + len >
1265 sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode))
1266 *alloc_required = 1;
1267 return 0;
1270 *alloc_required = 1;
1271 shift = sdp->sd_sb.sb_bsize_shift;
1272 BUG_ON(gfs2_is_dir(ip));
1273 end_of_file = (ip->i_disksize + sdp->sd_sb.sb_bsize - 1) >> shift;
1274 lblock = offset >> shift;
1275 lblock_stop = (offset + len + sdp->sd_sb.sb_bsize - 1) >> shift;
1276 if (lblock_stop > end_of_file)
1277 return 0;
1279 size = (lblock_stop - lblock) << shift;
1280 do {
1281 bh.b_state = 0;
1282 bh.b_size = size;
1283 gfs2_block_map(&ip->i_inode, lblock, &bh, 0);
1284 if (!buffer_mapped(&bh))
1285 return 0;
1286 size -= bh.b_size;
1287 lblock += (bh.b_size >> ip->i_inode.i_blkbits);
1288 } while(size > 0);
1290 *alloc_required = 0;
1291 return 0;