blob: dc2724fa7622b2b1492d0d547425e6dcc1e7e35c [file] [log] [blame]
Alex Tomasa86c6182006-10-11 01:21:03 -07001/*
2 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
3 * Written by Alex Tomas <alex@clusterfs.com>
4 *
5 * Architecture independence:
6 * Copyright (c) 2005, Bull S.A.
7 * Written by Pierre Peiffer <pierre.peiffer@bull.net>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public Licens
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
21 */
22
23/*
24 * Extents support for EXT4
25 *
26 * TODO:
27 * - ext4*_error() should be used in some situations
28 * - analyze all BUG()/BUG_ON(), use -EIO where appropriate
29 * - smart tree reduction
30 */
31
32#include <linux/module.h>
33#include <linux/fs.h>
34#include <linux/time.h>
35#include <linux/ext4_jbd2.h>
36#include <linux/jbd.h>
37#include <linux/smp_lock.h>
38#include <linux/highuid.h>
39#include <linux/pagemap.h>
40#include <linux/quotaops.h>
41#include <linux/string.h>
42#include <linux/slab.h>
43#include <linux/ext4_fs_extents.h>
44#include <asm/uaccess.h>
45
46
Randy Dunlapd0d856e2006-10-11 01:21:07 -070047/*
48 * ext_pblock:
49 * combine low and high parts of physical block number into ext4_fsblk_t
50 */
Avantika Mathur09b88252006-12-06 20:41:36 -080051static ext4_fsblk_t ext_pblock(struct ext4_extent *ex)
Alex Tomasf65e6fb2006-10-11 01:21:05 -070052{
53 ext4_fsblk_t block;
54
55 block = le32_to_cpu(ex->ee_start);
Mingming Cao9b8f1f02006-10-11 01:21:13 -070056 block |= ((ext4_fsblk_t) le16_to_cpu(ex->ee_start_hi) << 31) << 1;
Alex Tomasf65e6fb2006-10-11 01:21:05 -070057 return block;
58}
59
Randy Dunlapd0d856e2006-10-11 01:21:07 -070060/*
61 * idx_pblock:
62 * combine low and high parts of a leaf physical block number into ext4_fsblk_t
63 */
Avantika Mathur09b88252006-12-06 20:41:36 -080064static ext4_fsblk_t idx_pblock(struct ext4_extent_idx *ix)
Alex Tomasf65e6fb2006-10-11 01:21:05 -070065{
66 ext4_fsblk_t block;
67
68 block = le32_to_cpu(ix->ei_leaf);
Mingming Cao9b8f1f02006-10-11 01:21:13 -070069 block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1;
Alex Tomasf65e6fb2006-10-11 01:21:05 -070070 return block;
71}
72
Randy Dunlapd0d856e2006-10-11 01:21:07 -070073/*
74 * ext4_ext_store_pblock:
75 * stores a large physical block number into an extent struct,
76 * breaking it into parts
77 */
Avantika Mathur09b88252006-12-06 20:41:36 -080078static void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb)
Alex Tomasf65e6fb2006-10-11 01:21:05 -070079{
80 ex->ee_start = cpu_to_le32((unsigned long) (pb & 0xffffffff));
Mingming Cao9b8f1f02006-10-11 01:21:13 -070081 ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
Alex Tomasf65e6fb2006-10-11 01:21:05 -070082}
83
Randy Dunlapd0d856e2006-10-11 01:21:07 -070084/*
85 * ext4_idx_store_pblock:
86 * stores a large physical block number into an index struct,
87 * breaking it into parts
88 */
Avantika Mathur09b88252006-12-06 20:41:36 -080089static void ext4_idx_store_pblock(struct ext4_extent_idx *ix, ext4_fsblk_t pb)
Alex Tomasf65e6fb2006-10-11 01:21:05 -070090{
91 ix->ei_leaf = cpu_to_le32((unsigned long) (pb & 0xffffffff));
Mingming Cao9b8f1f02006-10-11 01:21:13 -070092 ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
Alex Tomasf65e6fb2006-10-11 01:21:05 -070093}
94
Alex Tomasa86c6182006-10-11 01:21:03 -070095static int ext4_ext_check_header(const char *function, struct inode *inode,
96 struct ext4_extent_header *eh)
97{
98 const char *error_msg = NULL;
99
100 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
101 error_msg = "invalid magic";
102 goto corrupted;
103 }
104 if (unlikely(eh->eh_max == 0)) {
105 error_msg = "invalid eh_max";
106 goto corrupted;
107 }
108 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
109 error_msg = "invalid eh_entries";
110 goto corrupted;
111 }
112 return 0;
113
114corrupted:
115 ext4_error(inode->i_sb, function,
116 "bad header in inode #%lu: %s - magic %x, "
117 "entries %u, max %u, depth %u",
118 inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic),
119 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
120 le16_to_cpu(eh->eh_depth));
121
122 return -EIO;
123}
124
125static handle_t *ext4_ext_journal_restart(handle_t *handle, int needed)
126{
127 int err;
128
129 if (handle->h_buffer_credits > needed)
130 return handle;
131 if (!ext4_journal_extend(handle, needed))
132 return handle;
133 err = ext4_journal_restart(handle, needed);
134
135 return handle;
136}
137
138/*
139 * could return:
140 * - EROFS
141 * - ENOMEM
142 */
143static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
144 struct ext4_ext_path *path)
145{
146 if (path->p_bh) {
147 /* path points to block */
148 return ext4_journal_get_write_access(handle, path->p_bh);
149 }
150 /* path points to leaf/index in inode body */
151 /* we use in-core data, no need to protect them */
152 return 0;
153}
154
155/*
156 * could return:
157 * - EROFS
158 * - ENOMEM
159 * - EIO
160 */
161static int ext4_ext_dirty(handle_t *handle, struct inode *inode,
162 struct ext4_ext_path *path)
163{
164 int err;
165 if (path->p_bh) {
166 /* path points to block */
167 err = ext4_journal_dirty_metadata(handle, path->p_bh);
168 } else {
169 /* path points to leaf/index in inode body */
170 err = ext4_mark_inode_dirty(handle, inode);
171 }
172 return err;
173}
174
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700175static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
Alex Tomasa86c6182006-10-11 01:21:03 -0700176 struct ext4_ext_path *path,
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700177 ext4_fsblk_t block)
Alex Tomasa86c6182006-10-11 01:21:03 -0700178{
179 struct ext4_inode_info *ei = EXT4_I(inode);
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700180 ext4_fsblk_t bg_start;
181 ext4_grpblk_t colour;
Alex Tomasa86c6182006-10-11 01:21:03 -0700182 int depth;
183
184 if (path) {
185 struct ext4_extent *ex;
186 depth = path->p_depth;
187
188 /* try to predict block placement */
Avantika Mathur7e028972006-12-06 20:41:33 -0800189 ex = path[depth].p_ext;
190 if (ex)
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700191 return ext_pblock(ex)+(block-le32_to_cpu(ex->ee_block));
Alex Tomasa86c6182006-10-11 01:21:03 -0700192
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700193 /* it looks like index is empty;
194 * try to find starting block from index itself */
Alex Tomasa86c6182006-10-11 01:21:03 -0700195 if (path[depth].p_bh)
196 return path[depth].p_bh->b_blocknr;
197 }
198
199 /* OK. use inode's group */
200 bg_start = (ei->i_block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) +
201 le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_first_data_block);
202 colour = (current->pid % 16) *
203 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
204 return bg_start + colour + block;
205}
206
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700207static ext4_fsblk_t
Alex Tomasa86c6182006-10-11 01:21:03 -0700208ext4_ext_new_block(handle_t *handle, struct inode *inode,
209 struct ext4_ext_path *path,
210 struct ext4_extent *ex, int *err)
211{
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700212 ext4_fsblk_t goal, newblock;
Alex Tomasa86c6182006-10-11 01:21:03 -0700213
214 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
215 newblock = ext4_new_block(handle, inode, goal, err);
216 return newblock;
217}
218
Avantika Mathur09b88252006-12-06 20:41:36 -0800219static int ext4_ext_space_block(struct inode *inode)
Alex Tomasa86c6182006-10-11 01:21:03 -0700220{
221 int size;
222
223 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
224 / sizeof(struct ext4_extent);
225#ifdef AGRESSIVE_TEST
226 if (size > 6)
227 size = 6;
228#endif
229 return size;
230}
231
Avantika Mathur09b88252006-12-06 20:41:36 -0800232static int ext4_ext_space_block_idx(struct inode *inode)
Alex Tomasa86c6182006-10-11 01:21:03 -0700233{
234 int size;
235
236 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
237 / sizeof(struct ext4_extent_idx);
238#ifdef AGRESSIVE_TEST
239 if (size > 5)
240 size = 5;
241#endif
242 return size;
243}
244
Avantika Mathur09b88252006-12-06 20:41:36 -0800245static int ext4_ext_space_root(struct inode *inode)
Alex Tomasa86c6182006-10-11 01:21:03 -0700246{
247 int size;
248
249 size = sizeof(EXT4_I(inode)->i_data);
250 size -= sizeof(struct ext4_extent_header);
251 size /= sizeof(struct ext4_extent);
252#ifdef AGRESSIVE_TEST
253 if (size > 3)
254 size = 3;
255#endif
256 return size;
257}
258
Avantika Mathur09b88252006-12-06 20:41:36 -0800259static int ext4_ext_space_root_idx(struct inode *inode)
Alex Tomasa86c6182006-10-11 01:21:03 -0700260{
261 int size;
262
263 size = sizeof(EXT4_I(inode)->i_data);
264 size -= sizeof(struct ext4_extent_header);
265 size /= sizeof(struct ext4_extent_idx);
266#ifdef AGRESSIVE_TEST
267 if (size > 4)
268 size = 4;
269#endif
270 return size;
271}
272
273#ifdef EXT_DEBUG
274static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
275{
276 int k, l = path->p_depth;
277
278 ext_debug("path:");
279 for (k = 0; k <= l; k++, path++) {
280 if (path->p_idx) {
Mingming Cao2ae02102006-10-11 01:21:11 -0700281 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block),
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700282 idx_pblock(path->p_idx));
Alex Tomasa86c6182006-10-11 01:21:03 -0700283 } else if (path->p_ext) {
Mingming Cao2ae02102006-10-11 01:21:11 -0700284 ext_debug(" %d:%d:%llu ",
Alex Tomasa86c6182006-10-11 01:21:03 -0700285 le32_to_cpu(path->p_ext->ee_block),
286 le16_to_cpu(path->p_ext->ee_len),
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700287 ext_pblock(path->p_ext));
Alex Tomasa86c6182006-10-11 01:21:03 -0700288 } else
289 ext_debug(" []");
290 }
291 ext_debug("\n");
292}
293
294static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
295{
296 int depth = ext_depth(inode);
297 struct ext4_extent_header *eh;
298 struct ext4_extent *ex;
299 int i;
300
301 if (!path)
302 return;
303
304 eh = path[depth].p_hdr;
305 ex = EXT_FIRST_EXTENT(eh);
306
307 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
Mingming Cao2ae02102006-10-11 01:21:11 -0700308 ext_debug("%d:%d:%llu ", le32_to_cpu(ex->ee_block),
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700309 le16_to_cpu(ex->ee_len), ext_pblock(ex));
Alex Tomasa86c6182006-10-11 01:21:03 -0700310 }
311 ext_debug("\n");
312}
313#else
314#define ext4_ext_show_path(inode,path)
315#define ext4_ext_show_leaf(inode,path)
316#endif
317
318static void ext4_ext_drop_refs(struct ext4_ext_path *path)
319{
320 int depth = path->p_depth;
321 int i;
322
323 for (i = 0; i <= depth; i++, path++)
324 if (path->p_bh) {
325 brelse(path->p_bh);
326 path->p_bh = NULL;
327 }
328}
329
330/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700331 * ext4_ext_binsearch_idx:
332 * binary search for the closest index of the given block
Alex Tomasa86c6182006-10-11 01:21:03 -0700333 */
334static void
335ext4_ext_binsearch_idx(struct inode *inode, struct ext4_ext_path *path, int block)
336{
337 struct ext4_extent_header *eh = path->p_hdr;
338 struct ext4_extent_idx *r, *l, *m;
339
340 BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC);
341 BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max));
342 BUG_ON(le16_to_cpu(eh->eh_entries) <= 0);
343
344 ext_debug("binsearch for %d(idx): ", block);
345
346 l = EXT_FIRST_INDEX(eh) + 1;
347 r = EXT_FIRST_INDEX(eh) + le16_to_cpu(eh->eh_entries) - 1;
348 while (l <= r) {
349 m = l + (r - l) / 2;
350 if (block < le32_to_cpu(m->ei_block))
351 r = m - 1;
352 else
353 l = m + 1;
354 ext_debug("%p(%u):%p(%u):%p(%u) ", l, l->ei_block,
355 m, m->ei_block, r, r->ei_block);
356 }
357
358 path->p_idx = l - 1;
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700359 ext_debug(" -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block),
360 idx_block(path->p_idx));
Alex Tomasa86c6182006-10-11 01:21:03 -0700361
362#ifdef CHECK_BINSEARCH
363 {
364 struct ext4_extent_idx *chix, *ix;
365 int k;
366
367 chix = ix = EXT_FIRST_INDEX(eh);
368 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
369 if (k != 0 &&
370 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
371 printk("k=%d, ix=0x%p, first=0x%p\n", k,
372 ix, EXT_FIRST_INDEX(eh));
373 printk("%u <= %u\n",
374 le32_to_cpu(ix->ei_block),
375 le32_to_cpu(ix[-1].ei_block));
376 }
377 BUG_ON(k && le32_to_cpu(ix->ei_block)
378 <= le32_to_cpu(ix[-1].ei_block));
379 if (block < le32_to_cpu(ix->ei_block))
380 break;
381 chix = ix;
382 }
383 BUG_ON(chix != path->p_idx);
384 }
385#endif
386
387}
388
389/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700390 * ext4_ext_binsearch:
391 * binary search for closest extent of the given block
Alex Tomasa86c6182006-10-11 01:21:03 -0700392 */
393static void
394ext4_ext_binsearch(struct inode *inode, struct ext4_ext_path *path, int block)
395{
396 struct ext4_extent_header *eh = path->p_hdr;
397 struct ext4_extent *r, *l, *m;
398
399 BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC);
400 BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max));
401
402 if (eh->eh_entries == 0) {
403 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700404 * this leaf is empty:
405 * we get such a leaf in split/add case
Alex Tomasa86c6182006-10-11 01:21:03 -0700406 */
407 return;
408 }
409
410 ext_debug("binsearch for %d: ", block);
411
412 l = EXT_FIRST_EXTENT(eh) + 1;
413 r = EXT_FIRST_EXTENT(eh) + le16_to_cpu(eh->eh_entries) - 1;
414
415 while (l <= r) {
416 m = l + (r - l) / 2;
417 if (block < le32_to_cpu(m->ee_block))
418 r = m - 1;
419 else
420 l = m + 1;
421 ext_debug("%p(%u):%p(%u):%p(%u) ", l, l->ee_block,
422 m, m->ee_block, r, r->ee_block);
423 }
424
425 path->p_ext = l - 1;
Mingming Cao2ae02102006-10-11 01:21:11 -0700426 ext_debug(" -> %d:%llu:%d ",
Alex Tomasa86c6182006-10-11 01:21:03 -0700427 le32_to_cpu(path->p_ext->ee_block),
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700428 ext_pblock(path->p_ext),
429 le16_to_cpu(path->p_ext->ee_len));
Alex Tomasa86c6182006-10-11 01:21:03 -0700430
431#ifdef CHECK_BINSEARCH
432 {
433 struct ext4_extent *chex, *ex;
434 int k;
435
436 chex = ex = EXT_FIRST_EXTENT(eh);
437 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
438 BUG_ON(k && le32_to_cpu(ex->ee_block)
439 <= le32_to_cpu(ex[-1].ee_block));
440 if (block < le32_to_cpu(ex->ee_block))
441 break;
442 chex = ex;
443 }
444 BUG_ON(chex != path->p_ext);
445 }
446#endif
447
448}
449
450int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
451{
452 struct ext4_extent_header *eh;
453
454 eh = ext_inode_hdr(inode);
455 eh->eh_depth = 0;
456 eh->eh_entries = 0;
457 eh->eh_magic = EXT4_EXT_MAGIC;
458 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode));
459 ext4_mark_inode_dirty(handle, inode);
460 ext4_ext_invalidate_cache(inode);
461 return 0;
462}
463
464struct ext4_ext_path *
465ext4_ext_find_extent(struct inode *inode, int block, struct ext4_ext_path *path)
466{
467 struct ext4_extent_header *eh;
468 struct buffer_head *bh;
469 short int depth, i, ppos = 0, alloc = 0;
470
471 eh = ext_inode_hdr(inode);
472 BUG_ON(eh == NULL);
473 if (ext4_ext_check_header(__FUNCTION__, inode, eh))
474 return ERR_PTR(-EIO);
475
476 i = depth = ext_depth(inode);
477
478 /* account possible depth increase */
479 if (!path) {
Avantika Mathur5d4958f2006-12-06 20:41:35 -0800480 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
Alex Tomasa86c6182006-10-11 01:21:03 -0700481 GFP_NOFS);
482 if (!path)
483 return ERR_PTR(-ENOMEM);
484 alloc = 1;
485 }
Alex Tomasa86c6182006-10-11 01:21:03 -0700486 path[0].p_hdr = eh;
487
488 /* walk through the tree */
489 while (i) {
490 ext_debug("depth %d: num %d, max %d\n",
491 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
492 ext4_ext_binsearch_idx(inode, path + ppos, block);
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700493 path[ppos].p_block = idx_pblock(path[ppos].p_idx);
Alex Tomasa86c6182006-10-11 01:21:03 -0700494 path[ppos].p_depth = i;
495 path[ppos].p_ext = NULL;
496
497 bh = sb_bread(inode->i_sb, path[ppos].p_block);
498 if (!bh)
499 goto err;
500
501 eh = ext_block_hdr(bh);
502 ppos++;
503 BUG_ON(ppos > depth);
504 path[ppos].p_bh = bh;
505 path[ppos].p_hdr = eh;
506 i--;
507
508 if (ext4_ext_check_header(__FUNCTION__, inode, eh))
509 goto err;
510 }
511
512 path[ppos].p_depth = i;
513 path[ppos].p_hdr = eh;
514 path[ppos].p_ext = NULL;
515 path[ppos].p_idx = NULL;
516
517 if (ext4_ext_check_header(__FUNCTION__, inode, eh))
518 goto err;
519
520 /* find extent */
521 ext4_ext_binsearch(inode, path + ppos, block);
522
523 ext4_ext_show_path(inode, path);
524
525 return path;
526
527err:
528 ext4_ext_drop_refs(path);
529 if (alloc)
530 kfree(path);
531 return ERR_PTR(-EIO);
532}
533
534/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700535 * ext4_ext_insert_index:
536 * insert new index [@logical;@ptr] into the block at @curp;
537 * check where to insert: before @curp or after @curp
Alex Tomasa86c6182006-10-11 01:21:03 -0700538 */
539static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
540 struct ext4_ext_path *curp,
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700541 int logical, ext4_fsblk_t ptr)
Alex Tomasa86c6182006-10-11 01:21:03 -0700542{
543 struct ext4_extent_idx *ix;
544 int len, err;
545
Avantika Mathur7e028972006-12-06 20:41:33 -0800546 err = ext4_ext_get_access(handle, inode, curp);
547 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -0700548 return err;
549
550 BUG_ON(logical == le32_to_cpu(curp->p_idx->ei_block));
551 len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
552 if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
553 /* insert after */
554 if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) {
555 len = (len - 1) * sizeof(struct ext4_extent_idx);
556 len = len < 0 ? 0 : len;
557 ext_debug("insert new index %d after: %d. "
558 "move %d from 0x%p to 0x%p\n",
559 logical, ptr, len,
560 (curp->p_idx + 1), (curp->p_idx + 2));
561 memmove(curp->p_idx + 2, curp->p_idx + 1, len);
562 }
563 ix = curp->p_idx + 1;
564 } else {
565 /* insert before */
566 len = len * sizeof(struct ext4_extent_idx);
567 len = len < 0 ? 0 : len;
568 ext_debug("insert new index %d before: %d. "
569 "move %d from 0x%p to 0x%p\n",
570 logical, ptr, len,
571 curp->p_idx, (curp->p_idx + 1));
572 memmove(curp->p_idx + 1, curp->p_idx, len);
573 ix = curp->p_idx;
574 }
575
576 ix->ei_block = cpu_to_le32(logical);
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700577 ext4_idx_store_pblock(ix, ptr);
Alex Tomasa86c6182006-10-11 01:21:03 -0700578 curp->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(curp->p_hdr->eh_entries)+1);
579
580 BUG_ON(le16_to_cpu(curp->p_hdr->eh_entries)
581 > le16_to_cpu(curp->p_hdr->eh_max));
582 BUG_ON(ix > EXT_LAST_INDEX(curp->p_hdr));
583
584 err = ext4_ext_dirty(handle, inode, curp);
585 ext4_std_error(inode->i_sb, err);
586
587 return err;
588}
589
590/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700591 * ext4_ext_split:
592 * inserts new subtree into the path, using free index entry
593 * at depth @at:
594 * - allocates all needed blocks (new leaf and all intermediate index blocks)
595 * - makes decision where to split
596 * - moves remaining extents and index entries (right to the split point)
597 * into the newly allocated blocks
598 * - initializes subtree
Alex Tomasa86c6182006-10-11 01:21:03 -0700599 */
600static int ext4_ext_split(handle_t *handle, struct inode *inode,
601 struct ext4_ext_path *path,
602 struct ext4_extent *newext, int at)
603{
604 struct buffer_head *bh = NULL;
605 int depth = ext_depth(inode);
606 struct ext4_extent_header *neh;
607 struct ext4_extent_idx *fidx;
608 struct ext4_extent *ex;
609 int i = at, k, m, a;
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700610 ext4_fsblk_t newblock, oldblock;
Alex Tomasa86c6182006-10-11 01:21:03 -0700611 __le32 border;
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700612 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
Alex Tomasa86c6182006-10-11 01:21:03 -0700613 int err = 0;
614
615 /* make decision: where to split? */
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700616 /* FIXME: now decision is simplest: at current extent */
Alex Tomasa86c6182006-10-11 01:21:03 -0700617
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700618 /* if current leaf will be split, then we should use
Alex Tomasa86c6182006-10-11 01:21:03 -0700619 * border from split point */
620 BUG_ON(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr));
621 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
622 border = path[depth].p_ext[1].ee_block;
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700623 ext_debug("leaf will be split."
Alex Tomasa86c6182006-10-11 01:21:03 -0700624 " next leaf starts at %d\n",
625 le32_to_cpu(border));
626 } else {
627 border = newext->ee_block;
628 ext_debug("leaf will be added."
629 " next leaf starts at %d\n",
630 le32_to_cpu(border));
631 }
632
633 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700634 * If error occurs, then we break processing
635 * and mark filesystem read-only. index won't
Alex Tomasa86c6182006-10-11 01:21:03 -0700636 * be inserted and tree will be in consistent
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700637 * state. Next mount will repair buffers too.
Alex Tomasa86c6182006-10-11 01:21:03 -0700638 */
639
640 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700641 * Get array to track all allocated blocks.
642 * We need this to handle errors and free blocks
643 * upon them.
Alex Tomasa86c6182006-10-11 01:21:03 -0700644 */
Avantika Mathur5d4958f2006-12-06 20:41:35 -0800645 ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
Alex Tomasa86c6182006-10-11 01:21:03 -0700646 if (!ablocks)
647 return -ENOMEM;
Alex Tomasa86c6182006-10-11 01:21:03 -0700648
649 /* allocate all needed blocks */
650 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
651 for (a = 0; a < depth - at; a++) {
652 newblock = ext4_ext_new_block(handle, inode, path, newext, &err);
653 if (newblock == 0)
654 goto cleanup;
655 ablocks[a] = newblock;
656 }
657
658 /* initialize new leaf */
659 newblock = ablocks[--a];
660 BUG_ON(newblock == 0);
661 bh = sb_getblk(inode->i_sb, newblock);
662 if (!bh) {
663 err = -EIO;
664 goto cleanup;
665 }
666 lock_buffer(bh);
667
Avantika Mathur7e028972006-12-06 20:41:33 -0800668 err = ext4_journal_get_create_access(handle, bh);
669 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -0700670 goto cleanup;
671
672 neh = ext_block_hdr(bh);
673 neh->eh_entries = 0;
674 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode));
675 neh->eh_magic = EXT4_EXT_MAGIC;
676 neh->eh_depth = 0;
677 ex = EXT_FIRST_EXTENT(neh);
678
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700679 /* move remainder of path[depth] to the new leaf */
Alex Tomasa86c6182006-10-11 01:21:03 -0700680 BUG_ON(path[depth].p_hdr->eh_entries != path[depth].p_hdr->eh_max);
681 /* start copy from next extent */
682 /* TODO: we could do it by single memmove */
683 m = 0;
684 path[depth].p_ext++;
685 while (path[depth].p_ext <=
686 EXT_MAX_EXTENT(path[depth].p_hdr)) {
Mingming Cao2ae02102006-10-11 01:21:11 -0700687 ext_debug("move %d:%llu:%d in new leaf %llu\n",
Alex Tomasa86c6182006-10-11 01:21:03 -0700688 le32_to_cpu(path[depth].p_ext->ee_block),
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700689 ext_pblock(path[depth].p_ext),
Alex Tomasa86c6182006-10-11 01:21:03 -0700690 le16_to_cpu(path[depth].p_ext->ee_len),
691 newblock);
692 /*memmove(ex++, path[depth].p_ext++,
693 sizeof(struct ext4_extent));
694 neh->eh_entries++;*/
695 path[depth].p_ext++;
696 m++;
697 }
698 if (m) {
699 memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m);
700 neh->eh_entries = cpu_to_le16(le16_to_cpu(neh->eh_entries)+m);
701 }
702
703 set_buffer_uptodate(bh);
704 unlock_buffer(bh);
705
Avantika Mathur7e028972006-12-06 20:41:33 -0800706 err = ext4_journal_dirty_metadata(handle, bh);
707 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -0700708 goto cleanup;
709 brelse(bh);
710 bh = NULL;
711
712 /* correct old leaf */
713 if (m) {
Avantika Mathur7e028972006-12-06 20:41:33 -0800714 err = ext4_ext_get_access(handle, inode, path + depth);
715 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -0700716 goto cleanup;
717 path[depth].p_hdr->eh_entries =
718 cpu_to_le16(le16_to_cpu(path[depth].p_hdr->eh_entries)-m);
Avantika Mathur7e028972006-12-06 20:41:33 -0800719 err = ext4_ext_dirty(handle, inode, path + depth);
720 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -0700721 goto cleanup;
722
723 }
724
725 /* create intermediate indexes */
726 k = depth - at - 1;
727 BUG_ON(k < 0);
728 if (k)
729 ext_debug("create %d intermediate indices\n", k);
730 /* insert new index into current index block */
731 /* current depth stored in i var */
732 i = depth - 1;
733 while (k--) {
734 oldblock = newblock;
735 newblock = ablocks[--a];
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700736 bh = sb_getblk(inode->i_sb, (ext4_fsblk_t)newblock);
Alex Tomasa86c6182006-10-11 01:21:03 -0700737 if (!bh) {
738 err = -EIO;
739 goto cleanup;
740 }
741 lock_buffer(bh);
742
Avantika Mathur7e028972006-12-06 20:41:33 -0800743 err = ext4_journal_get_create_access(handle, bh);
744 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -0700745 goto cleanup;
746
747 neh = ext_block_hdr(bh);
748 neh->eh_entries = cpu_to_le16(1);
749 neh->eh_magic = EXT4_EXT_MAGIC;
750 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode));
751 neh->eh_depth = cpu_to_le16(depth - i);
752 fidx = EXT_FIRST_INDEX(neh);
753 fidx->ei_block = border;
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700754 ext4_idx_store_pblock(fidx, oldblock);
Alex Tomasa86c6182006-10-11 01:21:03 -0700755
Mingming Cao2ae02102006-10-11 01:21:11 -0700756 ext_debug("int.index at %d (block %llu): %lu -> %llu\n", i,
Alex Tomasa86c6182006-10-11 01:21:03 -0700757 newblock, (unsigned long) le32_to_cpu(border),
758 oldblock);
759 /* copy indexes */
760 m = 0;
761 path[i].p_idx++;
762
763 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
764 EXT_MAX_INDEX(path[i].p_hdr));
765 BUG_ON(EXT_MAX_INDEX(path[i].p_hdr) !=
766 EXT_LAST_INDEX(path[i].p_hdr));
767 while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) {
Mingming Cao2ae02102006-10-11 01:21:11 -0700768 ext_debug("%d: move %d:%d in new index %llu\n", i,
Alex Tomasa86c6182006-10-11 01:21:03 -0700769 le32_to_cpu(path[i].p_idx->ei_block),
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700770 idx_pblock(path[i].p_idx),
Alex Tomasa86c6182006-10-11 01:21:03 -0700771 newblock);
772 /*memmove(++fidx, path[i].p_idx++,
773 sizeof(struct ext4_extent_idx));
774 neh->eh_entries++;
775 BUG_ON(neh->eh_entries > neh->eh_max);*/
776 path[i].p_idx++;
777 m++;
778 }
779 if (m) {
780 memmove(++fidx, path[i].p_idx - m,
781 sizeof(struct ext4_extent_idx) * m);
782 neh->eh_entries =
783 cpu_to_le16(le16_to_cpu(neh->eh_entries) + m);
784 }
785 set_buffer_uptodate(bh);
786 unlock_buffer(bh);
787
Avantika Mathur7e028972006-12-06 20:41:33 -0800788 err = ext4_journal_dirty_metadata(handle, bh);
789 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -0700790 goto cleanup;
791 brelse(bh);
792 bh = NULL;
793
794 /* correct old index */
795 if (m) {
796 err = ext4_ext_get_access(handle, inode, path + i);
797 if (err)
798 goto cleanup;
799 path[i].p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path[i].p_hdr->eh_entries)-m);
800 err = ext4_ext_dirty(handle, inode, path + i);
801 if (err)
802 goto cleanup;
803 }
804
805 i--;
806 }
807
808 /* insert new index */
Alex Tomasa86c6182006-10-11 01:21:03 -0700809 err = ext4_ext_insert_index(handle, inode, path + at,
810 le32_to_cpu(border), newblock);
811
812cleanup:
813 if (bh) {
814 if (buffer_locked(bh))
815 unlock_buffer(bh);
816 brelse(bh);
817 }
818
819 if (err) {
820 /* free all allocated blocks in error case */
821 for (i = 0; i < depth; i++) {
822 if (!ablocks[i])
823 continue;
824 ext4_free_blocks(handle, inode, ablocks[i], 1);
825 }
826 }
827 kfree(ablocks);
828
829 return err;
830}
831
832/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700833 * ext4_ext_grow_indepth:
834 * implements tree growing procedure:
835 * - allocates new block
836 * - moves top-level data (index block or leaf) into the new block
837 * - initializes new top-level, creating index that points to the
838 * just created block
Alex Tomasa86c6182006-10-11 01:21:03 -0700839 */
840static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
841 struct ext4_ext_path *path,
842 struct ext4_extent *newext)
843{
844 struct ext4_ext_path *curp = path;
845 struct ext4_extent_header *neh;
846 struct ext4_extent_idx *fidx;
847 struct buffer_head *bh;
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700848 ext4_fsblk_t newblock;
Alex Tomasa86c6182006-10-11 01:21:03 -0700849 int err = 0;
850
851 newblock = ext4_ext_new_block(handle, inode, path, newext, &err);
852 if (newblock == 0)
853 return err;
854
855 bh = sb_getblk(inode->i_sb, newblock);
856 if (!bh) {
857 err = -EIO;
858 ext4_std_error(inode->i_sb, err);
859 return err;
860 }
861 lock_buffer(bh);
862
Avantika Mathur7e028972006-12-06 20:41:33 -0800863 err = ext4_journal_get_create_access(handle, bh);
864 if (err) {
Alex Tomasa86c6182006-10-11 01:21:03 -0700865 unlock_buffer(bh);
866 goto out;
867 }
868
869 /* move top-level index/leaf into new block */
870 memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data));
871
872 /* set size of new block */
873 neh = ext_block_hdr(bh);
874 /* old root could have indexes or leaves
875 * so calculate e_max right way */
876 if (ext_depth(inode))
877 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode));
878 else
879 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode));
880 neh->eh_magic = EXT4_EXT_MAGIC;
881 set_buffer_uptodate(bh);
882 unlock_buffer(bh);
883
Avantika Mathur7e028972006-12-06 20:41:33 -0800884 err = ext4_journal_dirty_metadata(handle, bh);
885 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -0700886 goto out;
887
888 /* create index in new top-level index: num,max,pointer */
Avantika Mathur7e028972006-12-06 20:41:33 -0800889 err = ext4_ext_get_access(handle, inode, curp);
890 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -0700891 goto out;
892
893 curp->p_hdr->eh_magic = EXT4_EXT_MAGIC;
894 curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode));
895 curp->p_hdr->eh_entries = cpu_to_le16(1);
896 curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr);
897 /* FIXME: it works, but actually path[0] can be index */
898 curp->p_idx->ei_block = EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block;
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700899 ext4_idx_store_pblock(curp->p_idx, newblock);
Alex Tomasa86c6182006-10-11 01:21:03 -0700900
901 neh = ext_inode_hdr(inode);
902 fidx = EXT_FIRST_INDEX(neh);
Mingming Cao2ae02102006-10-11 01:21:11 -0700903 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
Alex Tomasa86c6182006-10-11 01:21:03 -0700904 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700905 le32_to_cpu(fidx->ei_block), idx_pblock(fidx));
Alex Tomasa86c6182006-10-11 01:21:03 -0700906
907 neh->eh_depth = cpu_to_le16(path->p_depth + 1);
908 err = ext4_ext_dirty(handle, inode, curp);
909out:
910 brelse(bh);
911
912 return err;
913}
914
915/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700916 * ext4_ext_create_new_leaf:
917 * finds empty index and adds new leaf.
918 * if no free index is found, then it requests in-depth growing.
Alex Tomasa86c6182006-10-11 01:21:03 -0700919 */
920static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
921 struct ext4_ext_path *path,
922 struct ext4_extent *newext)
923{
924 struct ext4_ext_path *curp;
925 int depth, i, err = 0;
926
927repeat:
928 i = depth = ext_depth(inode);
929
930 /* walk up to the tree and look for free index entry */
931 curp = path + depth;
932 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
933 i--;
934 curp--;
935 }
936
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700937 /* we use already allocated block for index block,
938 * so subsequent data blocks should be contiguous */
Alex Tomasa86c6182006-10-11 01:21:03 -0700939 if (EXT_HAS_FREE_INDEX(curp)) {
940 /* if we found index with free entry, then use that
941 * entry: create all needed subtree and add new leaf */
942 err = ext4_ext_split(handle, inode, path, newext, i);
943
944 /* refill path */
945 ext4_ext_drop_refs(path);
946 path = ext4_ext_find_extent(inode,
947 le32_to_cpu(newext->ee_block),
948 path);
949 if (IS_ERR(path))
950 err = PTR_ERR(path);
951 } else {
952 /* tree is full, time to grow in depth */
953 err = ext4_ext_grow_indepth(handle, inode, path, newext);
954 if (err)
955 goto out;
956
957 /* refill path */
958 ext4_ext_drop_refs(path);
959 path = ext4_ext_find_extent(inode,
960 le32_to_cpu(newext->ee_block),
961 path);
962 if (IS_ERR(path)) {
963 err = PTR_ERR(path);
964 goto out;
965 }
966
967 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700968 * only first (depth 0 -> 1) produces free space;
969 * in all other cases we have to split the grown tree
Alex Tomasa86c6182006-10-11 01:21:03 -0700970 */
971 depth = ext_depth(inode);
972 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700973 /* now we need to split */
Alex Tomasa86c6182006-10-11 01:21:03 -0700974 goto repeat;
975 }
976 }
977
978out:
979 return err;
980}
981
982/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700983 * ext4_ext_next_allocated_block:
984 * returns allocated block in subsequent extent or EXT_MAX_BLOCK.
985 * NOTE: it considers block number from index entry as
986 * allocated block. Thus, index entries have to be consistent
987 * with leaves.
Alex Tomasa86c6182006-10-11 01:21:03 -0700988 */
989static unsigned long
990ext4_ext_next_allocated_block(struct ext4_ext_path *path)
991{
992 int depth;
993
994 BUG_ON(path == NULL);
995 depth = path->p_depth;
996
997 if (depth == 0 && path->p_ext == NULL)
998 return EXT_MAX_BLOCK;
999
1000 while (depth >= 0) {
1001 if (depth == path->p_depth) {
1002 /* leaf */
1003 if (path[depth].p_ext !=
1004 EXT_LAST_EXTENT(path[depth].p_hdr))
1005 return le32_to_cpu(path[depth].p_ext[1].ee_block);
1006 } else {
1007 /* index */
1008 if (path[depth].p_idx !=
1009 EXT_LAST_INDEX(path[depth].p_hdr))
1010 return le32_to_cpu(path[depth].p_idx[1].ei_block);
1011 }
1012 depth--;
1013 }
1014
1015 return EXT_MAX_BLOCK;
1016}
1017
1018/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001019 * ext4_ext_next_leaf_block:
Alex Tomasa86c6182006-10-11 01:21:03 -07001020 * returns first allocated block from next leaf or EXT_MAX_BLOCK
1021 */
1022static unsigned ext4_ext_next_leaf_block(struct inode *inode,
Andrew Morton63f57932006-10-11 01:21:24 -07001023 struct ext4_ext_path *path)
Alex Tomasa86c6182006-10-11 01:21:03 -07001024{
1025 int depth;
1026
1027 BUG_ON(path == NULL);
1028 depth = path->p_depth;
1029
1030 /* zero-tree has no leaf blocks at all */
1031 if (depth == 0)
1032 return EXT_MAX_BLOCK;
1033
1034 /* go to index block */
1035 depth--;
1036
1037 while (depth >= 0) {
1038 if (path[depth].p_idx !=
1039 EXT_LAST_INDEX(path[depth].p_hdr))
1040 return le32_to_cpu(path[depth].p_idx[1].ei_block);
1041 depth--;
1042 }
1043
1044 return EXT_MAX_BLOCK;
1045}
1046
1047/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001048 * ext4_ext_correct_indexes:
1049 * if leaf gets modified and modified extent is first in the leaf,
1050 * then we have to correct all indexes above.
Alex Tomasa86c6182006-10-11 01:21:03 -07001051 * TODO: do we need to correct tree in all cases?
1052 */
1053int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1054 struct ext4_ext_path *path)
1055{
1056 struct ext4_extent_header *eh;
1057 int depth = ext_depth(inode);
1058 struct ext4_extent *ex;
1059 __le32 border;
1060 int k, err = 0;
1061
1062 eh = path[depth].p_hdr;
1063 ex = path[depth].p_ext;
1064 BUG_ON(ex == NULL);
1065 BUG_ON(eh == NULL);
1066
1067 if (depth == 0) {
1068 /* there is no tree at all */
1069 return 0;
1070 }
1071
1072 if (ex != EXT_FIRST_EXTENT(eh)) {
1073 /* we correct tree if first leaf got modified only */
1074 return 0;
1075 }
1076
1077 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001078 * TODO: we need correction if border is smaller than current one
Alex Tomasa86c6182006-10-11 01:21:03 -07001079 */
1080 k = depth - 1;
1081 border = path[depth].p_ext->ee_block;
Avantika Mathur7e028972006-12-06 20:41:33 -08001082 err = ext4_ext_get_access(handle, inode, path + k);
1083 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -07001084 return err;
1085 path[k].p_idx->ei_block = border;
Avantika Mathur7e028972006-12-06 20:41:33 -08001086 err = ext4_ext_dirty(handle, inode, path + k);
1087 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -07001088 return err;
1089
1090 while (k--) {
1091 /* change all left-side indexes */
1092 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1093 break;
Avantika Mathur7e028972006-12-06 20:41:33 -08001094 err = ext4_ext_get_access(handle, inode, path + k);
1095 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -07001096 break;
1097 path[k].p_idx->ei_block = border;
Avantika Mathur7e028972006-12-06 20:41:33 -08001098 err = ext4_ext_dirty(handle, inode, path + k);
1099 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -07001100 break;
1101 }
1102
1103 return err;
1104}
1105
Avantika Mathur09b88252006-12-06 20:41:36 -08001106static int
Alex Tomasa86c6182006-10-11 01:21:03 -07001107ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1108 struct ext4_extent *ex2)
1109{
Andrew Morton63f57932006-10-11 01:21:24 -07001110 if (le32_to_cpu(ex1->ee_block) + le16_to_cpu(ex1->ee_len) !=
1111 le32_to_cpu(ex2->ee_block))
Alex Tomasa86c6182006-10-11 01:21:03 -07001112 return 0;
1113
Suparna Bhattacharya471d4012006-10-11 01:21:06 -07001114 /*
1115 * To allow future support for preallocated extents to be added
1116 * as an RO_COMPAT feature, refuse to merge to extents if
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001117 * this can result in the top bit of ee_len being set.
Suparna Bhattacharya471d4012006-10-11 01:21:06 -07001118 */
1119 if (le16_to_cpu(ex1->ee_len) + le16_to_cpu(ex2->ee_len) > EXT_MAX_LEN)
1120 return 0;
Alex Tomasa86c6182006-10-11 01:21:03 -07001121#ifdef AGRESSIVE_TEST
1122 if (le16_to_cpu(ex1->ee_len) >= 4)
1123 return 0;
1124#endif
1125
Andrew Morton63f57932006-10-11 01:21:24 -07001126 if (ext_pblock(ex1) + le16_to_cpu(ex1->ee_len) == ext_pblock(ex2))
Alex Tomasa86c6182006-10-11 01:21:03 -07001127 return 1;
1128 return 0;
1129}
1130
1131/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001132 * ext4_ext_insert_extent:
1133 * tries to merge requsted extent into the existing extent or
1134 * inserts requested extent as new one into the tree,
1135 * creating new leaf in the no-space case.
Alex Tomasa86c6182006-10-11 01:21:03 -07001136 */
1137int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1138 struct ext4_ext_path *path,
1139 struct ext4_extent *newext)
1140{
1141 struct ext4_extent_header * eh;
1142 struct ext4_extent *ex, *fex;
1143 struct ext4_extent *nearex; /* nearest extent */
1144 struct ext4_ext_path *npath = NULL;
1145 int depth, len, err, next;
1146
1147 BUG_ON(newext->ee_len == 0);
1148 depth = ext_depth(inode);
1149 ex = path[depth].p_ext;
1150 BUG_ON(path[depth].p_hdr == NULL);
1151
1152 /* try to insert block into found extent and return */
1153 if (ex && ext4_can_extents_be_merged(inode, ex, newext)) {
Mingming Cao2ae02102006-10-11 01:21:11 -07001154 ext_debug("append %d block to %d:%d (from %llu)\n",
Alex Tomasa86c6182006-10-11 01:21:03 -07001155 le16_to_cpu(newext->ee_len),
1156 le32_to_cpu(ex->ee_block),
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001157 le16_to_cpu(ex->ee_len), ext_pblock(ex));
Avantika Mathur7e028972006-12-06 20:41:33 -08001158 err = ext4_ext_get_access(handle, inode, path + depth);
1159 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -07001160 return err;
1161 ex->ee_len = cpu_to_le16(le16_to_cpu(ex->ee_len)
1162 + le16_to_cpu(newext->ee_len));
1163 eh = path[depth].p_hdr;
1164 nearex = ex;
1165 goto merge;
1166 }
1167
1168repeat:
1169 depth = ext_depth(inode);
1170 eh = path[depth].p_hdr;
1171 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
1172 goto has_space;
1173
1174 /* probably next leaf has space for us? */
1175 fex = EXT_LAST_EXTENT(eh);
1176 next = ext4_ext_next_leaf_block(inode, path);
1177 if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block)
1178 && next != EXT_MAX_BLOCK) {
1179 ext_debug("next leaf block - %d\n", next);
1180 BUG_ON(npath != NULL);
1181 npath = ext4_ext_find_extent(inode, next, NULL);
1182 if (IS_ERR(npath))
1183 return PTR_ERR(npath);
1184 BUG_ON(npath->p_depth != path->p_depth);
1185 eh = npath[depth].p_hdr;
1186 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
1187 ext_debug("next leaf isnt full(%d)\n",
1188 le16_to_cpu(eh->eh_entries));
1189 path = npath;
1190 goto repeat;
1191 }
1192 ext_debug("next leaf has no free space(%d,%d)\n",
1193 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
1194 }
1195
1196 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001197 * There is no free space in the found leaf.
1198 * We're gonna add a new leaf in the tree.
Alex Tomasa86c6182006-10-11 01:21:03 -07001199 */
1200 err = ext4_ext_create_new_leaf(handle, inode, path, newext);
1201 if (err)
1202 goto cleanup;
1203 depth = ext_depth(inode);
1204 eh = path[depth].p_hdr;
1205
1206has_space:
1207 nearex = path[depth].p_ext;
1208
Avantika Mathur7e028972006-12-06 20:41:33 -08001209 err = ext4_ext_get_access(handle, inode, path + depth);
1210 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -07001211 goto cleanup;
1212
1213 if (!nearex) {
1214 /* there is no extent in this leaf, create first one */
Mingming Cao2ae02102006-10-11 01:21:11 -07001215 ext_debug("first extent in the leaf: %d:%llu:%d\n",
Alex Tomasa86c6182006-10-11 01:21:03 -07001216 le32_to_cpu(newext->ee_block),
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001217 ext_pblock(newext),
Alex Tomasa86c6182006-10-11 01:21:03 -07001218 le16_to_cpu(newext->ee_len));
1219 path[depth].p_ext = EXT_FIRST_EXTENT(eh);
1220 } else if (le32_to_cpu(newext->ee_block)
1221 > le32_to_cpu(nearex->ee_block)) {
1222/* BUG_ON(newext->ee_block == nearex->ee_block); */
1223 if (nearex != EXT_LAST_EXTENT(eh)) {
1224 len = EXT_MAX_EXTENT(eh) - nearex;
1225 len = (len - 1) * sizeof(struct ext4_extent);
1226 len = len < 0 ? 0 : len;
Mingming Cao2ae02102006-10-11 01:21:11 -07001227 ext_debug("insert %d:%llu:%d after: nearest 0x%p, "
Alex Tomasa86c6182006-10-11 01:21:03 -07001228 "move %d from 0x%p to 0x%p\n",
1229 le32_to_cpu(newext->ee_block),
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001230 ext_pblock(newext),
Alex Tomasa86c6182006-10-11 01:21:03 -07001231 le16_to_cpu(newext->ee_len),
1232 nearex, len, nearex + 1, nearex + 2);
1233 memmove(nearex + 2, nearex + 1, len);
1234 }
1235 path[depth].p_ext = nearex + 1;
1236 } else {
1237 BUG_ON(newext->ee_block == nearex->ee_block);
1238 len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent);
1239 len = len < 0 ? 0 : len;
Mingming Cao2ae02102006-10-11 01:21:11 -07001240 ext_debug("insert %d:%llu:%d before: nearest 0x%p, "
Alex Tomasa86c6182006-10-11 01:21:03 -07001241 "move %d from 0x%p to 0x%p\n",
1242 le32_to_cpu(newext->ee_block),
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001243 ext_pblock(newext),
Alex Tomasa86c6182006-10-11 01:21:03 -07001244 le16_to_cpu(newext->ee_len),
1245 nearex, len, nearex + 1, nearex + 2);
1246 memmove(nearex + 1, nearex, len);
1247 path[depth].p_ext = nearex;
1248 }
1249
1250 eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)+1);
1251 nearex = path[depth].p_ext;
1252 nearex->ee_block = newext->ee_block;
1253 nearex->ee_start = newext->ee_start;
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001254 nearex->ee_start_hi = newext->ee_start_hi;
Alex Tomasa86c6182006-10-11 01:21:03 -07001255 nearex->ee_len = newext->ee_len;
Alex Tomasa86c6182006-10-11 01:21:03 -07001256
1257merge:
1258 /* try to merge extents to the right */
1259 while (nearex < EXT_LAST_EXTENT(eh)) {
1260 if (!ext4_can_extents_be_merged(inode, nearex, nearex + 1))
1261 break;
1262 /* merge with next extent! */
1263 nearex->ee_len = cpu_to_le16(le16_to_cpu(nearex->ee_len)
1264 + le16_to_cpu(nearex[1].ee_len));
1265 if (nearex + 1 < EXT_LAST_EXTENT(eh)) {
1266 len = (EXT_LAST_EXTENT(eh) - nearex - 1)
1267 * sizeof(struct ext4_extent);
1268 memmove(nearex + 1, nearex + 2, len);
1269 }
1270 eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)-1);
1271 BUG_ON(eh->eh_entries == 0);
1272 }
1273
1274 /* try to merge extents to the left */
1275
1276 /* time to correct all indexes above */
1277 err = ext4_ext_correct_indexes(handle, inode, path);
1278 if (err)
1279 goto cleanup;
1280
1281 err = ext4_ext_dirty(handle, inode, path + depth);
1282
1283cleanup:
1284 if (npath) {
1285 ext4_ext_drop_refs(npath);
1286 kfree(npath);
1287 }
1288 ext4_ext_tree_changed(inode);
1289 ext4_ext_invalidate_cache(inode);
1290 return err;
1291}
1292
1293int ext4_ext_walk_space(struct inode *inode, unsigned long block,
1294 unsigned long num, ext_prepare_callback func,
1295 void *cbdata)
1296{
1297 struct ext4_ext_path *path = NULL;
1298 struct ext4_ext_cache cbex;
1299 struct ext4_extent *ex;
1300 unsigned long next, start = 0, end = 0;
1301 unsigned long last = block + num;
1302 int depth, exists, err = 0;
1303
1304 BUG_ON(func == NULL);
1305 BUG_ON(inode == NULL);
1306
1307 while (block < last && block != EXT_MAX_BLOCK) {
1308 num = last - block;
1309 /* find extent for this block */
1310 path = ext4_ext_find_extent(inode, block, path);
1311 if (IS_ERR(path)) {
1312 err = PTR_ERR(path);
1313 path = NULL;
1314 break;
1315 }
1316
1317 depth = ext_depth(inode);
1318 BUG_ON(path[depth].p_hdr == NULL);
1319 ex = path[depth].p_ext;
1320 next = ext4_ext_next_allocated_block(path);
1321
1322 exists = 0;
1323 if (!ex) {
1324 /* there is no extent yet, so try to allocate
1325 * all requested space */
1326 start = block;
1327 end = block + num;
1328 } else if (le32_to_cpu(ex->ee_block) > block) {
1329 /* need to allocate space before found extent */
1330 start = block;
1331 end = le32_to_cpu(ex->ee_block);
1332 if (block + num < end)
1333 end = block + num;
1334 } else if (block >=
1335 le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len)) {
1336 /* need to allocate space after found extent */
1337 start = block;
1338 end = block + num;
1339 if (end >= next)
1340 end = next;
1341 } else if (block >= le32_to_cpu(ex->ee_block)) {
1342 /*
1343 * some part of requested space is covered
1344 * by found extent
1345 */
1346 start = block;
1347 end = le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len);
1348 if (block + num < end)
1349 end = block + num;
1350 exists = 1;
1351 } else {
1352 BUG();
1353 }
1354 BUG_ON(end <= start);
1355
1356 if (!exists) {
1357 cbex.ec_block = start;
1358 cbex.ec_len = end - start;
1359 cbex.ec_start = 0;
1360 cbex.ec_type = EXT4_EXT_CACHE_GAP;
1361 } else {
1362 cbex.ec_block = le32_to_cpu(ex->ee_block);
1363 cbex.ec_len = le16_to_cpu(ex->ee_len);
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001364 cbex.ec_start = ext_pblock(ex);
Alex Tomasa86c6182006-10-11 01:21:03 -07001365 cbex.ec_type = EXT4_EXT_CACHE_EXTENT;
1366 }
1367
1368 BUG_ON(cbex.ec_len == 0);
1369 err = func(inode, path, &cbex, cbdata);
1370 ext4_ext_drop_refs(path);
1371
1372 if (err < 0)
1373 break;
1374 if (err == EXT_REPEAT)
1375 continue;
1376 else if (err == EXT_BREAK) {
1377 err = 0;
1378 break;
1379 }
1380
1381 if (ext_depth(inode) != depth) {
1382 /* depth was changed. we have to realloc path */
1383 kfree(path);
1384 path = NULL;
1385 }
1386
1387 block = cbex.ec_block + cbex.ec_len;
1388 }
1389
1390 if (path) {
1391 ext4_ext_drop_refs(path);
1392 kfree(path);
1393 }
1394
1395 return err;
1396}
1397
Avantika Mathur09b88252006-12-06 20:41:36 -08001398static void
Alex Tomasa86c6182006-10-11 01:21:03 -07001399ext4_ext_put_in_cache(struct inode *inode, __u32 block,
1400 __u32 len, __u32 start, int type)
1401{
1402 struct ext4_ext_cache *cex;
1403 BUG_ON(len == 0);
1404 cex = &EXT4_I(inode)->i_cached_extent;
1405 cex->ec_type = type;
1406 cex->ec_block = block;
1407 cex->ec_len = len;
1408 cex->ec_start = start;
1409}
1410
1411/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001412 * ext4_ext_put_gap_in_cache:
1413 * calculate boundaries of the gap that the requested block fits into
Alex Tomasa86c6182006-10-11 01:21:03 -07001414 * and cache this gap
1415 */
Avantika Mathur09b88252006-12-06 20:41:36 -08001416static void
Alex Tomasa86c6182006-10-11 01:21:03 -07001417ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
1418 unsigned long block)
1419{
1420 int depth = ext_depth(inode);
1421 unsigned long lblock, len;
1422 struct ext4_extent *ex;
1423
1424 ex = path[depth].p_ext;
1425 if (ex == NULL) {
1426 /* there is no extent yet, so gap is [0;-] */
1427 lblock = 0;
1428 len = EXT_MAX_BLOCK;
1429 ext_debug("cache gap(whole file):");
1430 } else if (block < le32_to_cpu(ex->ee_block)) {
1431 lblock = block;
1432 len = le32_to_cpu(ex->ee_block) - block;
1433 ext_debug("cache gap(before): %lu [%lu:%lu]",
1434 (unsigned long) block,
1435 (unsigned long) le32_to_cpu(ex->ee_block),
1436 (unsigned long) le16_to_cpu(ex->ee_len));
1437 } else if (block >= le32_to_cpu(ex->ee_block)
1438 + le16_to_cpu(ex->ee_len)) {
1439 lblock = le32_to_cpu(ex->ee_block)
1440 + le16_to_cpu(ex->ee_len);
1441 len = ext4_ext_next_allocated_block(path);
1442 ext_debug("cache gap(after): [%lu:%lu] %lu",
1443 (unsigned long) le32_to_cpu(ex->ee_block),
1444 (unsigned long) le16_to_cpu(ex->ee_len),
1445 (unsigned long) block);
1446 BUG_ON(len == lblock);
1447 len = len - lblock;
1448 } else {
1449 lblock = len = 0;
1450 BUG();
1451 }
1452
1453 ext_debug(" -> %lu:%lu\n", (unsigned long) lblock, len);
1454 ext4_ext_put_in_cache(inode, lblock, len, 0, EXT4_EXT_CACHE_GAP);
1455}
1456
Avantika Mathur09b88252006-12-06 20:41:36 -08001457static int
Alex Tomasa86c6182006-10-11 01:21:03 -07001458ext4_ext_in_cache(struct inode *inode, unsigned long block,
1459 struct ext4_extent *ex)
1460{
1461 struct ext4_ext_cache *cex;
1462
1463 cex = &EXT4_I(inode)->i_cached_extent;
1464
1465 /* has cache valid data? */
1466 if (cex->ec_type == EXT4_EXT_CACHE_NO)
1467 return EXT4_EXT_CACHE_NO;
1468
1469 BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP &&
1470 cex->ec_type != EXT4_EXT_CACHE_EXTENT);
1471 if (block >= cex->ec_block && block < cex->ec_block + cex->ec_len) {
1472 ex->ee_block = cpu_to_le32(cex->ec_block);
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001473 ext4_ext_store_pblock(ex, cex->ec_start);
Alex Tomasa86c6182006-10-11 01:21:03 -07001474 ex->ee_len = cpu_to_le16(cex->ec_len);
Mingming Cao2ae02102006-10-11 01:21:11 -07001475 ext_debug("%lu cached by %lu:%lu:%llu\n",
Alex Tomasa86c6182006-10-11 01:21:03 -07001476 (unsigned long) block,
1477 (unsigned long) cex->ec_block,
1478 (unsigned long) cex->ec_len,
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001479 cex->ec_start);
Alex Tomasa86c6182006-10-11 01:21:03 -07001480 return cex->ec_type;
1481 }
1482
1483 /* not in cache */
1484 return EXT4_EXT_CACHE_NO;
1485}
1486
1487/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001488 * ext4_ext_rm_idx:
1489 * removes index from the index block.
1490 * It's used in truncate case only, thus all requests are for
1491 * last index in the block only.
Alex Tomasa86c6182006-10-11 01:21:03 -07001492 */
1493int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
1494 struct ext4_ext_path *path)
1495{
1496 struct buffer_head *bh;
1497 int err;
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001498 ext4_fsblk_t leaf;
Alex Tomasa86c6182006-10-11 01:21:03 -07001499
1500 /* free index block */
1501 path--;
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001502 leaf = idx_pblock(path->p_idx);
Alex Tomasa86c6182006-10-11 01:21:03 -07001503 BUG_ON(path->p_hdr->eh_entries == 0);
Avantika Mathur7e028972006-12-06 20:41:33 -08001504 err = ext4_ext_get_access(handle, inode, path);
1505 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -07001506 return err;
1507 path->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path->p_hdr->eh_entries)-1);
Avantika Mathur7e028972006-12-06 20:41:33 -08001508 err = ext4_ext_dirty(handle, inode, path);
1509 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -07001510 return err;
Mingming Cao2ae02102006-10-11 01:21:11 -07001511 ext_debug("index is empty, remove it, free block %llu\n", leaf);
Alex Tomasa86c6182006-10-11 01:21:03 -07001512 bh = sb_find_get_block(inode->i_sb, leaf);
1513 ext4_forget(handle, 1, inode, bh, leaf);
1514 ext4_free_blocks(handle, inode, leaf, 1);
1515 return err;
1516}
1517
1518/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001519 * ext4_ext_calc_credits_for_insert:
1520 * This routine returns max. credits that the extent tree can consume.
Alex Tomasa86c6182006-10-11 01:21:03 -07001521 * It should be OK for low-performance paths like ->writepage()
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001522 * To allow many writing processes to fit into a single transaction,
1523 * the caller should calculate credits under truncate_mutex and
1524 * pass the actual path.
Alex Tomasa86c6182006-10-11 01:21:03 -07001525 */
Avantika Mathur09b88252006-12-06 20:41:36 -08001526int ext4_ext_calc_credits_for_insert(struct inode *inode,
Alex Tomasa86c6182006-10-11 01:21:03 -07001527 struct ext4_ext_path *path)
1528{
1529 int depth, needed;
1530
1531 if (path) {
1532 /* probably there is space in leaf? */
1533 depth = ext_depth(inode);
1534 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
1535 < le16_to_cpu(path[depth].p_hdr->eh_max))
1536 return 1;
1537 }
1538
1539 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001540 * given 32-bit logical block (4294967296 blocks), max. tree
Alex Tomasa86c6182006-10-11 01:21:03 -07001541 * can be 4 levels in depth -- 4 * 340^4 == 53453440000.
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001542 * Let's also add one more level for imbalance.
Alex Tomasa86c6182006-10-11 01:21:03 -07001543 */
1544 depth = 5;
1545
1546 /* allocation of new data block(s) */
1547 needed = 2;
1548
1549 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001550 * tree can be full, so it would need to grow in depth:
Johann Lombardifeb18922006-12-06 20:40:46 -08001551 * we need one credit to modify old root, credits for
1552 * new root will be added in split accounting
Alex Tomasa86c6182006-10-11 01:21:03 -07001553 */
Johann Lombardifeb18922006-12-06 20:40:46 -08001554 needed += 1;
Alex Tomasa86c6182006-10-11 01:21:03 -07001555
1556 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001557 * Index split can happen, we would need:
Alex Tomasa86c6182006-10-11 01:21:03 -07001558 * allocate intermediate indexes (bitmap + group)
1559 * + change two blocks at each level, but root (already included)
1560 */
Johann Lombardifeb18922006-12-06 20:40:46 -08001561 needed += (depth * 2) + (depth * 2);
Alex Tomasa86c6182006-10-11 01:21:03 -07001562
1563 /* any allocation modifies superblock */
1564 needed += 1;
1565
1566 return needed;
1567}
1568
1569static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
1570 struct ext4_extent *ex,
1571 unsigned long from, unsigned long to)
1572{
1573 struct buffer_head *bh;
1574 int i;
1575
1576#ifdef EXTENTS_STATS
1577 {
1578 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
1579 unsigned short ee_len = le16_to_cpu(ex->ee_len);
1580 spin_lock(&sbi->s_ext_stats_lock);
1581 sbi->s_ext_blocks += ee_len;
1582 sbi->s_ext_extents++;
1583 if (ee_len < sbi->s_ext_min)
1584 sbi->s_ext_min = ee_len;
1585 if (ee_len > sbi->s_ext_max)
1586 sbi->s_ext_max = ee_len;
1587 if (ext_depth(inode) > sbi->s_depth_max)
1588 sbi->s_depth_max = ext_depth(inode);
1589 spin_unlock(&sbi->s_ext_stats_lock);
1590 }
1591#endif
1592 if (from >= le32_to_cpu(ex->ee_block)
1593 && to == le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - 1) {
1594 /* tail removal */
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001595 unsigned long num;
1596 ext4_fsblk_t start;
Alex Tomasa86c6182006-10-11 01:21:03 -07001597 num = le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - from;
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001598 start = ext_pblock(ex) + le16_to_cpu(ex->ee_len) - num;
Mingming Cao2ae02102006-10-11 01:21:11 -07001599 ext_debug("free last %lu blocks starting %llu\n", num, start);
Alex Tomasa86c6182006-10-11 01:21:03 -07001600 for (i = 0; i < num; i++) {
1601 bh = sb_find_get_block(inode->i_sb, start + i);
1602 ext4_forget(handle, 0, inode, bh, start + i);
1603 }
1604 ext4_free_blocks(handle, inode, start, num);
1605 } else if (from == le32_to_cpu(ex->ee_block)
1606 && to <= le32_to_cpu(ex->ee_block) + le16_to_cpu(ex->ee_len) - 1) {
1607 printk("strange request: removal %lu-%lu from %u:%u\n",
1608 from, to, le32_to_cpu(ex->ee_block), le16_to_cpu(ex->ee_len));
1609 } else {
1610 printk("strange request: removal(2) %lu-%lu from %u:%u\n",
1611 from, to, le32_to_cpu(ex->ee_block), le16_to_cpu(ex->ee_len));
1612 }
1613 return 0;
1614}
1615
1616static int
1617ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
1618 struct ext4_ext_path *path, unsigned long start)
1619{
1620 int err = 0, correct_index = 0;
1621 int depth = ext_depth(inode), credits;
1622 struct ext4_extent_header *eh;
1623 unsigned a, b, block, num;
1624 unsigned long ex_ee_block;
1625 unsigned short ex_ee_len;
1626 struct ext4_extent *ex;
1627
1628 ext_debug("truncate since %lu in leaf\n", start);
1629 if (!path[depth].p_hdr)
1630 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
1631 eh = path[depth].p_hdr;
1632 BUG_ON(eh == NULL);
1633 BUG_ON(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max));
1634 BUG_ON(eh->eh_magic != EXT4_EXT_MAGIC);
1635
1636 /* find where to start removing */
1637 ex = EXT_LAST_EXTENT(eh);
1638
1639 ex_ee_block = le32_to_cpu(ex->ee_block);
1640 ex_ee_len = le16_to_cpu(ex->ee_len);
1641
1642 while (ex >= EXT_FIRST_EXTENT(eh) &&
1643 ex_ee_block + ex_ee_len > start) {
1644 ext_debug("remove ext %lu:%u\n", ex_ee_block, ex_ee_len);
1645 path[depth].p_ext = ex;
1646
1647 a = ex_ee_block > start ? ex_ee_block : start;
1648 b = ex_ee_block + ex_ee_len - 1 < EXT_MAX_BLOCK ?
1649 ex_ee_block + ex_ee_len - 1 : EXT_MAX_BLOCK;
1650
1651 ext_debug(" border %u:%u\n", a, b);
1652
1653 if (a != ex_ee_block && b != ex_ee_block + ex_ee_len - 1) {
1654 block = 0;
1655 num = 0;
1656 BUG();
1657 } else if (a != ex_ee_block) {
1658 /* remove tail of the extent */
1659 block = ex_ee_block;
1660 num = a - block;
1661 } else if (b != ex_ee_block + ex_ee_len - 1) {
1662 /* remove head of the extent */
1663 block = a;
1664 num = b - a;
1665 /* there is no "make a hole" API yet */
1666 BUG();
1667 } else {
1668 /* remove whole extent: excellent! */
1669 block = ex_ee_block;
1670 num = 0;
1671 BUG_ON(a != ex_ee_block);
1672 BUG_ON(b != ex_ee_block + ex_ee_len - 1);
1673 }
1674
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001675 /* at present, extent can't cross block group: */
Alex Tomasa86c6182006-10-11 01:21:03 -07001676 /* leaf + bitmap + group desc + sb + inode */
1677 credits = 5;
1678 if (ex == EXT_FIRST_EXTENT(eh)) {
1679 correct_index = 1;
1680 credits += (ext_depth(inode)) + 1;
1681 }
1682#ifdef CONFIG_QUOTA
1683 credits += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
1684#endif
1685
1686 handle = ext4_ext_journal_restart(handle, credits);
1687 if (IS_ERR(handle)) {
1688 err = PTR_ERR(handle);
1689 goto out;
1690 }
1691
1692 err = ext4_ext_get_access(handle, inode, path + depth);
1693 if (err)
1694 goto out;
1695
1696 err = ext4_remove_blocks(handle, inode, ex, a, b);
1697 if (err)
1698 goto out;
1699
1700 if (num == 0) {
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001701 /* this extent is removed; mark slot entirely unused */
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001702 ext4_ext_store_pblock(ex, 0);
Alex Tomasa86c6182006-10-11 01:21:03 -07001703 eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)-1);
1704 }
1705
1706 ex->ee_block = cpu_to_le32(block);
1707 ex->ee_len = cpu_to_le16(num);
1708
1709 err = ext4_ext_dirty(handle, inode, path + depth);
1710 if (err)
1711 goto out;
1712
Mingming Cao2ae02102006-10-11 01:21:11 -07001713 ext_debug("new extent: %u:%u:%llu\n", block, num,
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001714 ext_pblock(ex));
Alex Tomasa86c6182006-10-11 01:21:03 -07001715 ex--;
1716 ex_ee_block = le32_to_cpu(ex->ee_block);
1717 ex_ee_len = le16_to_cpu(ex->ee_len);
1718 }
1719
1720 if (correct_index && eh->eh_entries)
1721 err = ext4_ext_correct_indexes(handle, inode, path);
1722
1723 /* if this leaf is free, then we should
1724 * remove it from index block above */
1725 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
1726 err = ext4_ext_rm_idx(handle, inode, path + depth);
1727
1728out:
1729 return err;
1730}
1731
1732/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001733 * ext4_ext_more_to_rm:
1734 * returns 1 if current index has to be freed (even partial)
Alex Tomasa86c6182006-10-11 01:21:03 -07001735 */
Avantika Mathur09b88252006-12-06 20:41:36 -08001736static int
Alex Tomasa86c6182006-10-11 01:21:03 -07001737ext4_ext_more_to_rm(struct ext4_ext_path *path)
1738{
1739 BUG_ON(path->p_idx == NULL);
1740
1741 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
1742 return 0;
1743
1744 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001745 * if truncate on deeper level happened, it wasn't partial,
Alex Tomasa86c6182006-10-11 01:21:03 -07001746 * so we have to consider current index for truncation
1747 */
1748 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
1749 return 0;
1750 return 1;
1751}
1752
1753int ext4_ext_remove_space(struct inode *inode, unsigned long start)
1754{
1755 struct super_block *sb = inode->i_sb;
1756 int depth = ext_depth(inode);
1757 struct ext4_ext_path *path;
1758 handle_t *handle;
1759 int i = 0, err = 0;
1760
1761 ext_debug("truncate since %lu\n", start);
1762
1763 /* probably first extent we're gonna free will be last in block */
1764 handle = ext4_journal_start(inode, depth + 1);
1765 if (IS_ERR(handle))
1766 return PTR_ERR(handle);
1767
1768 ext4_ext_invalidate_cache(inode);
1769
1770 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001771 * We start scanning from right side, freeing all the blocks
1772 * after i_size and walking into the tree depth-wise.
Alex Tomasa86c6182006-10-11 01:21:03 -07001773 */
Avantika Mathur5d4958f2006-12-06 20:41:35 -08001774 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_KERNEL);
Alex Tomasa86c6182006-10-11 01:21:03 -07001775 if (path == NULL) {
1776 ext4_journal_stop(handle);
1777 return -ENOMEM;
1778 }
Alex Tomasa86c6182006-10-11 01:21:03 -07001779 path[0].p_hdr = ext_inode_hdr(inode);
1780 if (ext4_ext_check_header(__FUNCTION__, inode, path[0].p_hdr)) {
1781 err = -EIO;
1782 goto out;
1783 }
1784 path[0].p_depth = depth;
1785
1786 while (i >= 0 && err == 0) {
1787 if (i == depth) {
1788 /* this is leaf block */
1789 err = ext4_ext_rm_leaf(handle, inode, path, start);
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001790 /* root level has p_bh == NULL, brelse() eats this */
Alex Tomasa86c6182006-10-11 01:21:03 -07001791 brelse(path[i].p_bh);
1792 path[i].p_bh = NULL;
1793 i--;
1794 continue;
1795 }
1796
1797 /* this is index block */
1798 if (!path[i].p_hdr) {
1799 ext_debug("initialize header\n");
1800 path[i].p_hdr = ext_block_hdr(path[i].p_bh);
1801 if (ext4_ext_check_header(__FUNCTION__, inode,
1802 path[i].p_hdr)) {
1803 err = -EIO;
1804 goto out;
1805 }
1806 }
1807
1808 BUG_ON(le16_to_cpu(path[i].p_hdr->eh_entries)
1809 > le16_to_cpu(path[i].p_hdr->eh_max));
1810 BUG_ON(path[i].p_hdr->eh_magic != EXT4_EXT_MAGIC);
1811
1812 if (!path[i].p_idx) {
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001813 /* this level hasn't been touched yet */
Alex Tomasa86c6182006-10-11 01:21:03 -07001814 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
1815 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
1816 ext_debug("init index ptr: hdr 0x%p, num %d\n",
1817 path[i].p_hdr,
1818 le16_to_cpu(path[i].p_hdr->eh_entries));
1819 } else {
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001820 /* we were already here, see at next index */
Alex Tomasa86c6182006-10-11 01:21:03 -07001821 path[i].p_idx--;
1822 }
1823
1824 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
1825 i, EXT_FIRST_INDEX(path[i].p_hdr),
1826 path[i].p_idx);
1827 if (ext4_ext_more_to_rm(path + i)) {
1828 /* go to the next level */
Mingming Cao2ae02102006-10-11 01:21:11 -07001829 ext_debug("move to level %d (block %llu)\n",
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001830 i + 1, idx_pblock(path[i].p_idx));
Alex Tomasa86c6182006-10-11 01:21:03 -07001831 memset(path + i + 1, 0, sizeof(*path));
1832 path[i+1].p_bh =
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001833 sb_bread(sb, idx_pblock(path[i].p_idx));
Alex Tomasa86c6182006-10-11 01:21:03 -07001834 if (!path[i+1].p_bh) {
1835 /* should we reset i_size? */
1836 err = -EIO;
1837 break;
1838 }
1839
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001840 /* save actual number of indexes since this
1841 * number is changed at the next iteration */
Alex Tomasa86c6182006-10-11 01:21:03 -07001842 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
1843 i++;
1844 } else {
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001845 /* we finished processing this index, go up */
Alex Tomasa86c6182006-10-11 01:21:03 -07001846 if (path[i].p_hdr->eh_entries == 0 && i > 0) {
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001847 /* index is empty, remove it;
Alex Tomasa86c6182006-10-11 01:21:03 -07001848 * handle must be already prepared by the
1849 * truncatei_leaf() */
1850 err = ext4_ext_rm_idx(handle, inode, path + i);
1851 }
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001852 /* root level has p_bh == NULL, brelse() eats this */
Alex Tomasa86c6182006-10-11 01:21:03 -07001853 brelse(path[i].p_bh);
1854 path[i].p_bh = NULL;
1855 i--;
1856 ext_debug("return to level %d\n", i);
1857 }
1858 }
1859
1860 /* TODO: flexible tree reduction should be here */
1861 if (path->p_hdr->eh_entries == 0) {
1862 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001863 * truncate to zero freed all the tree,
1864 * so we need to correct eh_depth
Alex Tomasa86c6182006-10-11 01:21:03 -07001865 */
1866 err = ext4_ext_get_access(handle, inode, path);
1867 if (err == 0) {
1868 ext_inode_hdr(inode)->eh_depth = 0;
1869 ext_inode_hdr(inode)->eh_max =
1870 cpu_to_le16(ext4_ext_space_root(inode));
1871 err = ext4_ext_dirty(handle, inode, path);
1872 }
1873 }
1874out:
1875 ext4_ext_tree_changed(inode);
1876 ext4_ext_drop_refs(path);
1877 kfree(path);
1878 ext4_journal_stop(handle);
1879
1880 return err;
1881}
1882
1883/*
1884 * called at mount time
1885 */
1886void ext4_ext_init(struct super_block *sb)
1887{
1888 /*
1889 * possible initialization would be here
1890 */
1891
1892 if (test_opt(sb, EXTENTS)) {
1893 printk("EXT4-fs: file extents enabled");
1894#ifdef AGRESSIVE_TEST
1895 printk(", agressive tests");
1896#endif
1897#ifdef CHECK_BINSEARCH
1898 printk(", check binsearch");
1899#endif
1900#ifdef EXTENTS_STATS
1901 printk(", stats");
1902#endif
1903 printk("\n");
1904#ifdef EXTENTS_STATS
1905 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
1906 EXT4_SB(sb)->s_ext_min = 1 << 30;
1907 EXT4_SB(sb)->s_ext_max = 0;
1908#endif
1909 }
1910}
1911
1912/*
1913 * called at umount time
1914 */
1915void ext4_ext_release(struct super_block *sb)
1916{
1917 if (!test_opt(sb, EXTENTS))
1918 return;
1919
1920#ifdef EXTENTS_STATS
1921 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
1922 struct ext4_sb_info *sbi = EXT4_SB(sb);
1923 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
1924 sbi->s_ext_blocks, sbi->s_ext_extents,
1925 sbi->s_ext_blocks / sbi->s_ext_extents);
1926 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
1927 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
1928 }
1929#endif
1930}
1931
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001932int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
1933 ext4_fsblk_t iblock,
Alex Tomasa86c6182006-10-11 01:21:03 -07001934 unsigned long max_blocks, struct buffer_head *bh_result,
1935 int create, int extend_disksize)
1936{
1937 struct ext4_ext_path *path = NULL;
1938 struct ext4_extent newex, *ex;
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001939 ext4_fsblk_t goal, newblock;
1940 int err = 0, depth;
Alex Tomasa86c6182006-10-11 01:21:03 -07001941 unsigned long allocated = 0;
1942
1943 __clear_bit(BH_New, &bh_result->b_state);
1944 ext_debug("blocks %d/%lu requested for inode %u\n", (int) iblock,
1945 max_blocks, (unsigned) inode->i_ino);
1946 mutex_lock(&EXT4_I(inode)->truncate_mutex);
1947
1948 /* check in cache */
Avantika Mathur7e028972006-12-06 20:41:33 -08001949 goal = ext4_ext_in_cache(inode, iblock, &newex);
1950 if (goal) {
Alex Tomasa86c6182006-10-11 01:21:03 -07001951 if (goal == EXT4_EXT_CACHE_GAP) {
1952 if (!create) {
1953 /* block isn't allocated yet and
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001954 * user doesn't want to allocate it */
Alex Tomasa86c6182006-10-11 01:21:03 -07001955 goto out2;
1956 }
1957 /* we should allocate requested block */
1958 } else if (goal == EXT4_EXT_CACHE_EXTENT) {
1959 /* block is already allocated */
1960 newblock = iblock
1961 - le32_to_cpu(newex.ee_block)
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001962 + ext_pblock(&newex);
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001963 /* number of remaining blocks in the extent */
Alex Tomasa86c6182006-10-11 01:21:03 -07001964 allocated = le16_to_cpu(newex.ee_len) -
1965 (iblock - le32_to_cpu(newex.ee_block));
1966 goto out;
1967 } else {
1968 BUG();
1969 }
1970 }
1971
1972 /* find extent for this block */
1973 path = ext4_ext_find_extent(inode, iblock, NULL);
1974 if (IS_ERR(path)) {
1975 err = PTR_ERR(path);
1976 path = NULL;
1977 goto out2;
1978 }
1979
1980 depth = ext_depth(inode);
1981
1982 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001983 * consistent leaf must not be empty;
1984 * this situation is possible, though, _during_ tree modification;
Alex Tomasa86c6182006-10-11 01:21:03 -07001985 * this is why assert can't be put in ext4_ext_find_extent()
1986 */
1987 BUG_ON(path[depth].p_ext == NULL && depth != 0);
1988
Avantika Mathur7e028972006-12-06 20:41:33 -08001989 ex = path[depth].p_ext;
1990 if (ex) {
Alex Tomasa86c6182006-10-11 01:21:03 -07001991 unsigned long ee_block = le32_to_cpu(ex->ee_block);
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001992 ext4_fsblk_t ee_start = ext_pblock(ex);
Alex Tomasa86c6182006-10-11 01:21:03 -07001993 unsigned short ee_len = le16_to_cpu(ex->ee_len);
Suparna Bhattacharya471d4012006-10-11 01:21:06 -07001994
1995 /*
1996 * Allow future support for preallocated extents to be added
1997 * as an RO_COMPAT feature:
1998 * Uninitialized extents are treated as holes, except that
1999 * we avoid (fail) allocating new blocks during a write.
2000 */
2001 if (ee_len > EXT_MAX_LEN)
2002 goto out2;
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002003 /* if found extent covers block, simply return it */
Alex Tomasa86c6182006-10-11 01:21:03 -07002004 if (iblock >= ee_block && iblock < ee_block + ee_len) {
2005 newblock = iblock - ee_block + ee_start;
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002006 /* number of remaining blocks in the extent */
Alex Tomasa86c6182006-10-11 01:21:03 -07002007 allocated = ee_len - (iblock - ee_block);
Mingming Cao2ae02102006-10-11 01:21:11 -07002008 ext_debug("%d fit into %lu:%d -> %llu\n", (int) iblock,
Alex Tomasa86c6182006-10-11 01:21:03 -07002009 ee_block, ee_len, newblock);
2010 ext4_ext_put_in_cache(inode, ee_block, ee_len,
2011 ee_start, EXT4_EXT_CACHE_EXTENT);
2012 goto out;
2013 }
2014 }
2015
2016 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002017 * requested block isn't allocated yet;
Alex Tomasa86c6182006-10-11 01:21:03 -07002018 * we couldn't try to create block if create flag is zero
2019 */
2020 if (!create) {
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002021 /* put just found gap into cache to speed up
2022 * subsequent requests */
Alex Tomasa86c6182006-10-11 01:21:03 -07002023 ext4_ext_put_gap_in_cache(inode, path, iblock);
2024 goto out2;
2025 }
2026 /*
Andrew Morton63f57932006-10-11 01:21:24 -07002027 * Okay, we need to do block allocation. Lazily initialize the block
2028 * allocation info here if necessary.
2029 */
Alex Tomasa86c6182006-10-11 01:21:03 -07002030 if (S_ISREG(inode->i_mode) && (!EXT4_I(inode)->i_block_alloc_info))
2031 ext4_init_block_alloc_info(inode);
2032
2033 /* allocate new block */
2034 goal = ext4_ext_find_goal(inode, path, iblock);
2035 allocated = max_blocks;
2036 newblock = ext4_new_blocks(handle, inode, goal, &allocated, &err);
2037 if (!newblock)
2038 goto out2;
Mingming Cao2ae02102006-10-11 01:21:11 -07002039 ext_debug("allocate new block: goal %llu, found %llu/%lu\n",
Alex Tomasa86c6182006-10-11 01:21:03 -07002040 goal, newblock, allocated);
2041
2042 /* try to insert new extent into found leaf and return */
2043 newex.ee_block = cpu_to_le32(iblock);
Alex Tomasf65e6fb2006-10-11 01:21:05 -07002044 ext4_ext_store_pblock(&newex, newblock);
Alex Tomasa86c6182006-10-11 01:21:03 -07002045 newex.ee_len = cpu_to_le16(allocated);
2046 err = ext4_ext_insert_extent(handle, inode, path, &newex);
2047 if (err)
2048 goto out2;
2049
2050 if (extend_disksize && inode->i_size > EXT4_I(inode)->i_disksize)
2051 EXT4_I(inode)->i_disksize = inode->i_size;
2052
2053 /* previous routine could use block we allocated */
Alex Tomasf65e6fb2006-10-11 01:21:05 -07002054 newblock = ext_pblock(&newex);
Alex Tomasa86c6182006-10-11 01:21:03 -07002055 __set_bit(BH_New, &bh_result->b_state);
2056
2057 ext4_ext_put_in_cache(inode, iblock, allocated, newblock,
2058 EXT4_EXT_CACHE_EXTENT);
2059out:
2060 if (allocated > max_blocks)
2061 allocated = max_blocks;
2062 ext4_ext_show_leaf(inode, path);
2063 __set_bit(BH_Mapped, &bh_result->b_state);
2064 bh_result->b_bdev = inode->i_sb->s_bdev;
2065 bh_result->b_blocknr = newblock;
2066out2:
2067 if (path) {
2068 ext4_ext_drop_refs(path);
2069 kfree(path);
2070 }
2071 mutex_unlock(&EXT4_I(inode)->truncate_mutex);
2072
2073 return err ? err : allocated;
2074}
2075
2076void ext4_ext_truncate(struct inode * inode, struct page *page)
2077{
2078 struct address_space *mapping = inode->i_mapping;
2079 struct super_block *sb = inode->i_sb;
2080 unsigned long last_block;
2081 handle_t *handle;
2082 int err = 0;
2083
2084 /*
2085 * probably first extent we're gonna free will be last in block
2086 */
2087 err = ext4_writepage_trans_blocks(inode) + 3;
2088 handle = ext4_journal_start(inode, err);
2089 if (IS_ERR(handle)) {
2090 if (page) {
2091 clear_highpage(page);
2092 flush_dcache_page(page);
2093 unlock_page(page);
2094 page_cache_release(page);
2095 }
2096 return;
2097 }
2098
2099 if (page)
2100 ext4_block_truncate_page(handle, page, mapping, inode->i_size);
2101
2102 mutex_lock(&EXT4_I(inode)->truncate_mutex);
2103 ext4_ext_invalidate_cache(inode);
2104
2105 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002106 * TODO: optimization is possible here.
2107 * Probably we need not scan at all,
2108 * because page truncation is enough.
Alex Tomasa86c6182006-10-11 01:21:03 -07002109 */
2110 if (ext4_orphan_add(handle, inode))
2111 goto out_stop;
2112
2113 /* we have to know where to truncate from in crash case */
2114 EXT4_I(inode)->i_disksize = inode->i_size;
2115 ext4_mark_inode_dirty(handle, inode);
2116
2117 last_block = (inode->i_size + sb->s_blocksize - 1)
2118 >> EXT4_BLOCK_SIZE_BITS(sb);
2119 err = ext4_ext_remove_space(inode, last_block);
2120
2121 /* In a multi-transaction truncate, we only make the final
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002122 * transaction synchronous. */
Alex Tomasa86c6182006-10-11 01:21:03 -07002123 if (IS_SYNC(inode))
2124 handle->h_sync = 1;
2125
2126out_stop:
2127 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002128 * If this was a simple ftruncate() and the file will remain alive,
Alex Tomasa86c6182006-10-11 01:21:03 -07002129 * then we need to clear up the orphan record which we created above.
2130 * However, if this was a real unlink then we were called by
2131 * ext4_delete_inode(), and we allow that function to clean up the
2132 * orphan info for us.
2133 */
2134 if (inode->i_nlink)
2135 ext4_orphan_del(handle, inode);
2136
2137 mutex_unlock(&EXT4_I(inode)->truncate_mutex);
2138 ext4_journal_stop(handle);
2139}
2140
2141/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002142 * ext4_ext_writepage_trans_blocks:
2143 * calculate max number of blocks we could modify
Alex Tomasa86c6182006-10-11 01:21:03 -07002144 * in order to allocate new block for an inode
2145 */
2146int ext4_ext_writepage_trans_blocks(struct inode *inode, int num)
2147{
2148 int needed;
2149
2150 needed = ext4_ext_calc_credits_for_insert(inode, NULL);
2151
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002152 /* caller wants to allocate num blocks, but note it includes sb */
Alex Tomasa86c6182006-10-11 01:21:03 -07002153 needed = needed * num - (num - 1);
2154
2155#ifdef CONFIG_QUOTA
2156 needed += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
2157#endif
2158
2159 return needed;
2160}
2161
2162EXPORT_SYMBOL(ext4_mark_inode_dirty);
2163EXPORT_SYMBOL(ext4_ext_invalidate_cache);
2164EXPORT_SYMBOL(ext4_ext_insert_extent);
2165EXPORT_SYMBOL(ext4_ext_walk_space);
2166EXPORT_SYMBOL(ext4_ext_find_goal);
2167EXPORT_SYMBOL(ext4_ext_calc_credits_for_insert);
2168