blob: 85287742f2ae487562be3a8ac39e40774a5de9d3 [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>
Mingming Caocd02ff02007-10-16 18:38:25 -040036#include <linux/jbd2.h>
Alex Tomasa86c6182006-10-11 01:21:03 -070037#include <linux/highuid.h>
38#include <linux/pagemap.h>
39#include <linux/quotaops.h>
40#include <linux/string.h>
41#include <linux/slab.h>
Amit Aroraa2df2a62007-07-17 21:42:41 -040042#include <linux/falloc.h>
Alex Tomasa86c6182006-10-11 01:21:03 -070043#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
Aneesh Kumar K.Vb3776112007-10-16 18:38:25 -040055 block = le32_to_cpu(ex->ee_start_lo);
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
Aneesh Kumar K.Vd8dd0b42007-10-16 18:38:25 -040068 block = le32_to_cpu(ix->ei_leaf_lo);
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{
Aneesh Kumar K.Vb3776112007-10-16 18:38:25 -040080 ex->ee_start_lo = 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{
Aneesh Kumar K.Vd8dd0b42007-10-16 18:38:25 -040091 ix->ei_leaf_lo = 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 handle_t *ext4_ext_journal_restart(handle_t *handle, int needed)
96{
97 int err;
98
99 if (handle->h_buffer_credits > needed)
100 return handle;
101 if (!ext4_journal_extend(handle, needed))
102 return handle;
103 err = ext4_journal_restart(handle, needed);
104
105 return handle;
106}
107
108/*
109 * could return:
110 * - EROFS
111 * - ENOMEM
112 */
113static int ext4_ext_get_access(handle_t *handle, struct inode *inode,
114 struct ext4_ext_path *path)
115{
116 if (path->p_bh) {
117 /* path points to block */
118 return ext4_journal_get_write_access(handle, path->p_bh);
119 }
120 /* path points to leaf/index in inode body */
121 /* we use in-core data, no need to protect them */
122 return 0;
123}
124
125/*
126 * could return:
127 * - EROFS
128 * - ENOMEM
129 * - EIO
130 */
131static int ext4_ext_dirty(handle_t *handle, struct inode *inode,
132 struct ext4_ext_path *path)
133{
134 int err;
135 if (path->p_bh) {
136 /* path points to block */
137 err = ext4_journal_dirty_metadata(handle, path->p_bh);
138 } else {
139 /* path points to leaf/index in inode body */
140 err = ext4_mark_inode_dirty(handle, inode);
141 }
142 return err;
143}
144
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700145static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
Alex Tomasa86c6182006-10-11 01:21:03 -0700146 struct ext4_ext_path *path,
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700147 ext4_fsblk_t block)
Alex Tomasa86c6182006-10-11 01:21:03 -0700148{
149 struct ext4_inode_info *ei = EXT4_I(inode);
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700150 ext4_fsblk_t bg_start;
151 ext4_grpblk_t colour;
Alex Tomasa86c6182006-10-11 01:21:03 -0700152 int depth;
153
154 if (path) {
155 struct ext4_extent *ex;
156 depth = path->p_depth;
157
158 /* try to predict block placement */
Avantika Mathur7e028972006-12-06 20:41:33 -0800159 ex = path[depth].p_ext;
160 if (ex)
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700161 return ext_pblock(ex)+(block-le32_to_cpu(ex->ee_block));
Alex Tomasa86c6182006-10-11 01:21:03 -0700162
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700163 /* it looks like index is empty;
164 * try to find starting block from index itself */
Alex Tomasa86c6182006-10-11 01:21:03 -0700165 if (path[depth].p_bh)
166 return path[depth].p_bh->b_blocknr;
167 }
168
169 /* OK. use inode's group */
170 bg_start = (ei->i_block_group * EXT4_BLOCKS_PER_GROUP(inode->i_sb)) +
171 le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_first_data_block);
172 colour = (current->pid % 16) *
173 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
174 return bg_start + colour + block;
175}
176
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700177static ext4_fsblk_t
Alex Tomasa86c6182006-10-11 01:21:03 -0700178ext4_ext_new_block(handle_t *handle, struct inode *inode,
179 struct ext4_ext_path *path,
180 struct ext4_extent *ex, int *err)
181{
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700182 ext4_fsblk_t goal, newblock;
Alex Tomasa86c6182006-10-11 01:21:03 -0700183
184 goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
185 newblock = ext4_new_block(handle, inode, goal, err);
186 return newblock;
187}
188
Avantika Mathur09b88252006-12-06 20:41:36 -0800189static int ext4_ext_space_block(struct inode *inode)
Alex Tomasa86c6182006-10-11 01:21:03 -0700190{
191 int size;
192
193 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
194 / sizeof(struct ext4_extent);
Robert P. J. Daybbf2f9f2007-02-17 19:20:16 +0100195#ifdef AGGRESSIVE_TEST
Alex Tomasa86c6182006-10-11 01:21:03 -0700196 if (size > 6)
197 size = 6;
198#endif
199 return size;
200}
201
Avantika Mathur09b88252006-12-06 20:41:36 -0800202static int ext4_ext_space_block_idx(struct inode *inode)
Alex Tomasa86c6182006-10-11 01:21:03 -0700203{
204 int size;
205
206 size = (inode->i_sb->s_blocksize - sizeof(struct ext4_extent_header))
207 / sizeof(struct ext4_extent_idx);
Robert P. J. Daybbf2f9f2007-02-17 19:20:16 +0100208#ifdef AGGRESSIVE_TEST
Alex Tomasa86c6182006-10-11 01:21:03 -0700209 if (size > 5)
210 size = 5;
211#endif
212 return size;
213}
214
Avantika Mathur09b88252006-12-06 20:41:36 -0800215static int ext4_ext_space_root(struct inode *inode)
Alex Tomasa86c6182006-10-11 01:21:03 -0700216{
217 int size;
218
219 size = sizeof(EXT4_I(inode)->i_data);
220 size -= sizeof(struct ext4_extent_header);
221 size /= sizeof(struct ext4_extent);
Robert P. J. Daybbf2f9f2007-02-17 19:20:16 +0100222#ifdef AGGRESSIVE_TEST
Alex Tomasa86c6182006-10-11 01:21:03 -0700223 if (size > 3)
224 size = 3;
225#endif
226 return size;
227}
228
Avantika Mathur09b88252006-12-06 20:41:36 -0800229static int ext4_ext_space_root_idx(struct inode *inode)
Alex Tomasa86c6182006-10-11 01:21:03 -0700230{
231 int size;
232
233 size = sizeof(EXT4_I(inode)->i_data);
234 size -= sizeof(struct ext4_extent_header);
235 size /= sizeof(struct ext4_extent_idx);
Robert P. J. Daybbf2f9f2007-02-17 19:20:16 +0100236#ifdef AGGRESSIVE_TEST
Alex Tomasa86c6182006-10-11 01:21:03 -0700237 if (size > 4)
238 size = 4;
239#endif
240 return size;
241}
242
Alex Tomasc29c0ae2007-07-18 09:19:09 -0400243static int
244ext4_ext_max_entries(struct inode *inode, int depth)
245{
246 int max;
247
248 if (depth == ext_depth(inode)) {
249 if (depth == 0)
250 max = ext4_ext_space_root(inode);
251 else
252 max = ext4_ext_space_root_idx(inode);
253 } else {
254 if (depth == 0)
255 max = ext4_ext_space_block(inode);
256 else
257 max = ext4_ext_space_block_idx(inode);
258 }
259
260 return max;
261}
262
263static int __ext4_ext_check_header(const char *function, struct inode *inode,
264 struct ext4_extent_header *eh,
265 int depth)
266{
267 const char *error_msg;
268 int max = 0;
269
270 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) {
271 error_msg = "invalid magic";
272 goto corrupted;
273 }
274 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) {
275 error_msg = "unexpected eh_depth";
276 goto corrupted;
277 }
278 if (unlikely(eh->eh_max == 0)) {
279 error_msg = "invalid eh_max";
280 goto corrupted;
281 }
282 max = ext4_ext_max_entries(inode, depth);
283 if (unlikely(le16_to_cpu(eh->eh_max) > max)) {
284 error_msg = "too large eh_max";
285 goto corrupted;
286 }
287 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) {
288 error_msg = "invalid eh_entries";
289 goto corrupted;
290 }
291 return 0;
292
293corrupted:
294 ext4_error(inode->i_sb, function,
295 "bad header in inode #%lu: %s - magic %x, "
296 "entries %u, max %u(%u), depth %u(%u)",
297 inode->i_ino, error_msg, le16_to_cpu(eh->eh_magic),
298 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max),
299 max, le16_to_cpu(eh->eh_depth), depth);
300
301 return -EIO;
302}
303
304#define ext4_ext_check_header(inode, eh, depth) \
305 __ext4_ext_check_header(__FUNCTION__, inode, eh, depth)
306
Alex Tomasa86c6182006-10-11 01:21:03 -0700307#ifdef EXT_DEBUG
308static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path)
309{
310 int k, l = path->p_depth;
311
312 ext_debug("path:");
313 for (k = 0; k <= l; k++, path++) {
314 if (path->p_idx) {
Mingming Cao2ae02102006-10-11 01:21:11 -0700315 ext_debug(" %d->%llu", le32_to_cpu(path->p_idx->ei_block),
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700316 idx_pblock(path->p_idx));
Alex Tomasa86c6182006-10-11 01:21:03 -0700317 } else if (path->p_ext) {
Mingming Cao2ae02102006-10-11 01:21:11 -0700318 ext_debug(" %d:%d:%llu ",
Alex Tomasa86c6182006-10-11 01:21:03 -0700319 le32_to_cpu(path->p_ext->ee_block),
Amit Aroraa2df2a62007-07-17 21:42:41 -0400320 ext4_ext_get_actual_len(path->p_ext),
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700321 ext_pblock(path->p_ext));
Alex Tomasa86c6182006-10-11 01:21:03 -0700322 } else
323 ext_debug(" []");
324 }
325 ext_debug("\n");
326}
327
328static void ext4_ext_show_leaf(struct inode *inode, struct ext4_ext_path *path)
329{
330 int depth = ext_depth(inode);
331 struct ext4_extent_header *eh;
332 struct ext4_extent *ex;
333 int i;
334
335 if (!path)
336 return;
337
338 eh = path[depth].p_hdr;
339 ex = EXT_FIRST_EXTENT(eh);
340
341 for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ex++) {
Mingming Cao2ae02102006-10-11 01:21:11 -0700342 ext_debug("%d:%d:%llu ", le32_to_cpu(ex->ee_block),
Amit Aroraa2df2a62007-07-17 21:42:41 -0400343 ext4_ext_get_actual_len(ex), ext_pblock(ex));
Alex Tomasa86c6182006-10-11 01:21:03 -0700344 }
345 ext_debug("\n");
346}
347#else
348#define ext4_ext_show_path(inode,path)
349#define ext4_ext_show_leaf(inode,path)
350#endif
351
352static void ext4_ext_drop_refs(struct ext4_ext_path *path)
353{
354 int depth = path->p_depth;
355 int i;
356
357 for (i = 0; i <= depth; i++, path++)
358 if (path->p_bh) {
359 brelse(path->p_bh);
360 path->p_bh = NULL;
361 }
362}
363
364/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700365 * ext4_ext_binsearch_idx:
366 * binary search for the closest index of the given block
Alex Tomasc29c0ae2007-07-18 09:19:09 -0400367 * the header must be checked before calling this
Alex Tomasa86c6182006-10-11 01:21:03 -0700368 */
369static void
370ext4_ext_binsearch_idx(struct inode *inode, struct ext4_ext_path *path, int block)
371{
372 struct ext4_extent_header *eh = path->p_hdr;
373 struct ext4_extent_idx *r, *l, *m;
374
Alex Tomasa86c6182006-10-11 01:21:03 -0700375
376 ext_debug("binsearch for %d(idx): ", block);
377
378 l = EXT_FIRST_INDEX(eh) + 1;
Dmitry Monakhove9f410b2007-07-18 09:09:15 -0400379 r = EXT_LAST_INDEX(eh);
Alex Tomasa86c6182006-10-11 01:21:03 -0700380 while (l <= r) {
381 m = l + (r - l) / 2;
382 if (block < le32_to_cpu(m->ei_block))
383 r = m - 1;
384 else
385 l = m + 1;
Dmitry Monakhov26d535e2007-07-18 08:33:37 -0400386 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ei_block),
387 m, le32_to_cpu(m->ei_block),
388 r, le32_to_cpu(r->ei_block));
Alex Tomasa86c6182006-10-11 01:21:03 -0700389 }
390
391 path->p_idx = l - 1;
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700392 ext_debug(" -> %d->%lld ", le32_to_cpu(path->p_idx->ei_block),
Dmitry Monakhov26d535e2007-07-18 08:33:37 -0400393 idx_pblock(path->p_idx));
Alex Tomasa86c6182006-10-11 01:21:03 -0700394
395#ifdef CHECK_BINSEARCH
396 {
397 struct ext4_extent_idx *chix, *ix;
398 int k;
399
400 chix = ix = EXT_FIRST_INDEX(eh);
401 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ix++) {
402 if (k != 0 &&
403 le32_to_cpu(ix->ei_block) <= le32_to_cpu(ix[-1].ei_block)) {
404 printk("k=%d, ix=0x%p, first=0x%p\n", k,
405 ix, EXT_FIRST_INDEX(eh));
406 printk("%u <= %u\n",
407 le32_to_cpu(ix->ei_block),
408 le32_to_cpu(ix[-1].ei_block));
409 }
410 BUG_ON(k && le32_to_cpu(ix->ei_block)
Dave Kleikamp8c55e202007-05-24 13:04:54 -0400411 <= le32_to_cpu(ix[-1].ei_block));
Alex Tomasa86c6182006-10-11 01:21:03 -0700412 if (block < le32_to_cpu(ix->ei_block))
413 break;
414 chix = ix;
415 }
416 BUG_ON(chix != path->p_idx);
417 }
418#endif
419
420}
421
422/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700423 * ext4_ext_binsearch:
424 * binary search for closest extent of the given block
Alex Tomasc29c0ae2007-07-18 09:19:09 -0400425 * the header must be checked before calling this
Alex Tomasa86c6182006-10-11 01:21:03 -0700426 */
427static void
428ext4_ext_binsearch(struct inode *inode, struct ext4_ext_path *path, int block)
429{
430 struct ext4_extent_header *eh = path->p_hdr;
431 struct ext4_extent *r, *l, *m;
432
Alex Tomasa86c6182006-10-11 01:21:03 -0700433 if (eh->eh_entries == 0) {
434 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700435 * this leaf is empty:
436 * we get such a leaf in split/add case
Alex Tomasa86c6182006-10-11 01:21:03 -0700437 */
438 return;
439 }
440
441 ext_debug("binsearch for %d: ", block);
442
443 l = EXT_FIRST_EXTENT(eh) + 1;
Dmitry Monakhove9f410b2007-07-18 09:09:15 -0400444 r = EXT_LAST_EXTENT(eh);
Alex Tomasa86c6182006-10-11 01:21:03 -0700445
446 while (l <= r) {
447 m = l + (r - l) / 2;
448 if (block < le32_to_cpu(m->ee_block))
449 r = m - 1;
450 else
451 l = m + 1;
Dmitry Monakhov26d535e2007-07-18 08:33:37 -0400452 ext_debug("%p(%u):%p(%u):%p(%u) ", l, le32_to_cpu(l->ee_block),
453 m, le32_to_cpu(m->ee_block),
454 r, le32_to_cpu(r->ee_block));
Alex Tomasa86c6182006-10-11 01:21:03 -0700455 }
456
457 path->p_ext = l - 1;
Mingming Cao2ae02102006-10-11 01:21:11 -0700458 ext_debug(" -> %d:%llu:%d ",
Dave Kleikamp8c55e202007-05-24 13:04:54 -0400459 le32_to_cpu(path->p_ext->ee_block),
460 ext_pblock(path->p_ext),
Amit Aroraa2df2a62007-07-17 21:42:41 -0400461 ext4_ext_get_actual_len(path->p_ext));
Alex Tomasa86c6182006-10-11 01:21:03 -0700462
463#ifdef CHECK_BINSEARCH
464 {
465 struct ext4_extent *chex, *ex;
466 int k;
467
468 chex = ex = EXT_FIRST_EXTENT(eh);
469 for (k = 0; k < le16_to_cpu(eh->eh_entries); k++, ex++) {
470 BUG_ON(k && le32_to_cpu(ex->ee_block)
Dave Kleikamp8c55e202007-05-24 13:04:54 -0400471 <= le32_to_cpu(ex[-1].ee_block));
Alex Tomasa86c6182006-10-11 01:21:03 -0700472 if (block < le32_to_cpu(ex->ee_block))
473 break;
474 chex = ex;
475 }
476 BUG_ON(chex != path->p_ext);
477 }
478#endif
479
480}
481
482int ext4_ext_tree_init(handle_t *handle, struct inode *inode)
483{
484 struct ext4_extent_header *eh;
485
486 eh = ext_inode_hdr(inode);
487 eh->eh_depth = 0;
488 eh->eh_entries = 0;
489 eh->eh_magic = EXT4_EXT_MAGIC;
490 eh->eh_max = cpu_to_le16(ext4_ext_space_root(inode));
491 ext4_mark_inode_dirty(handle, inode);
492 ext4_ext_invalidate_cache(inode);
493 return 0;
494}
495
496struct ext4_ext_path *
497ext4_ext_find_extent(struct inode *inode, int block, struct ext4_ext_path *path)
498{
499 struct ext4_extent_header *eh;
500 struct buffer_head *bh;
501 short int depth, i, ppos = 0, alloc = 0;
502
503 eh = ext_inode_hdr(inode);
Alex Tomasc29c0ae2007-07-18 09:19:09 -0400504 depth = ext_depth(inode);
505 if (ext4_ext_check_header(inode, eh, depth))
Alex Tomasa86c6182006-10-11 01:21:03 -0700506 return ERR_PTR(-EIO);
507
Alex Tomasa86c6182006-10-11 01:21:03 -0700508
509 /* account possible depth increase */
510 if (!path) {
Avantika Mathur5d4958f2006-12-06 20:41:35 -0800511 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 2),
Alex Tomasa86c6182006-10-11 01:21:03 -0700512 GFP_NOFS);
513 if (!path)
514 return ERR_PTR(-ENOMEM);
515 alloc = 1;
516 }
Alex Tomasa86c6182006-10-11 01:21:03 -0700517 path[0].p_hdr = eh;
518
Alex Tomasc29c0ae2007-07-18 09:19:09 -0400519 i = depth;
Alex Tomasa86c6182006-10-11 01:21:03 -0700520 /* walk through the tree */
521 while (i) {
522 ext_debug("depth %d: num %d, max %d\n",
523 ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
Alex Tomasc29c0ae2007-07-18 09:19:09 -0400524
Alex Tomasa86c6182006-10-11 01:21:03 -0700525 ext4_ext_binsearch_idx(inode, path + ppos, block);
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700526 path[ppos].p_block = idx_pblock(path[ppos].p_idx);
Alex Tomasa86c6182006-10-11 01:21:03 -0700527 path[ppos].p_depth = i;
528 path[ppos].p_ext = NULL;
529
530 bh = sb_bread(inode->i_sb, path[ppos].p_block);
531 if (!bh)
532 goto err;
533
534 eh = ext_block_hdr(bh);
535 ppos++;
536 BUG_ON(ppos > depth);
537 path[ppos].p_bh = bh;
538 path[ppos].p_hdr = eh;
539 i--;
540
Alex Tomasc29c0ae2007-07-18 09:19:09 -0400541 if (ext4_ext_check_header(inode, eh, i))
Alex Tomasa86c6182006-10-11 01:21:03 -0700542 goto err;
543 }
544
545 path[ppos].p_depth = i;
546 path[ppos].p_hdr = eh;
547 path[ppos].p_ext = NULL;
548 path[ppos].p_idx = NULL;
549
Alex Tomasa86c6182006-10-11 01:21:03 -0700550 /* find extent */
551 ext4_ext_binsearch(inode, path + ppos, block);
552
553 ext4_ext_show_path(inode, path);
554
555 return path;
556
557err:
558 ext4_ext_drop_refs(path);
559 if (alloc)
560 kfree(path);
561 return ERR_PTR(-EIO);
562}
563
564/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700565 * ext4_ext_insert_index:
566 * insert new index [@logical;@ptr] into the block at @curp;
567 * check where to insert: before @curp or after @curp
Alex Tomasa86c6182006-10-11 01:21:03 -0700568 */
569static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
570 struct ext4_ext_path *curp,
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700571 int logical, ext4_fsblk_t ptr)
Alex Tomasa86c6182006-10-11 01:21:03 -0700572{
573 struct ext4_extent_idx *ix;
574 int len, err;
575
Avantika Mathur7e028972006-12-06 20:41:33 -0800576 err = ext4_ext_get_access(handle, inode, curp);
577 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -0700578 return err;
579
580 BUG_ON(logical == le32_to_cpu(curp->p_idx->ei_block));
581 len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
582 if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
583 /* insert after */
584 if (curp->p_idx != EXT_LAST_INDEX(curp->p_hdr)) {
585 len = (len - 1) * sizeof(struct ext4_extent_idx);
586 len = len < 0 ? 0 : len;
Dmitry Monakhov26d535e2007-07-18 08:33:37 -0400587 ext_debug("insert new index %d after: %llu. "
Alex Tomasa86c6182006-10-11 01:21:03 -0700588 "move %d from 0x%p to 0x%p\n",
589 logical, ptr, len,
590 (curp->p_idx + 1), (curp->p_idx + 2));
591 memmove(curp->p_idx + 2, curp->p_idx + 1, len);
592 }
593 ix = curp->p_idx + 1;
594 } else {
595 /* insert before */
596 len = len * sizeof(struct ext4_extent_idx);
597 len = len < 0 ? 0 : len;
Dmitry Monakhov26d535e2007-07-18 08:33:37 -0400598 ext_debug("insert new index %d before: %llu. "
Alex Tomasa86c6182006-10-11 01:21:03 -0700599 "move %d from 0x%p to 0x%p\n",
600 logical, ptr, len,
601 curp->p_idx, (curp->p_idx + 1));
602 memmove(curp->p_idx + 1, curp->p_idx, len);
603 ix = curp->p_idx;
604 }
605
606 ix->ei_block = cpu_to_le32(logical);
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700607 ext4_idx_store_pblock(ix, ptr);
Alex Tomasa86c6182006-10-11 01:21:03 -0700608 curp->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(curp->p_hdr->eh_entries)+1);
609
610 BUG_ON(le16_to_cpu(curp->p_hdr->eh_entries)
Dave Kleikamp8c55e202007-05-24 13:04:54 -0400611 > le16_to_cpu(curp->p_hdr->eh_max));
Alex Tomasa86c6182006-10-11 01:21:03 -0700612 BUG_ON(ix > EXT_LAST_INDEX(curp->p_hdr));
613
614 err = ext4_ext_dirty(handle, inode, curp);
615 ext4_std_error(inode->i_sb, err);
616
617 return err;
618}
619
620/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700621 * ext4_ext_split:
622 * inserts new subtree into the path, using free index entry
623 * at depth @at:
624 * - allocates all needed blocks (new leaf and all intermediate index blocks)
625 * - makes decision where to split
626 * - moves remaining extents and index entries (right to the split point)
627 * into the newly allocated blocks
628 * - initializes subtree
Alex Tomasa86c6182006-10-11 01:21:03 -0700629 */
630static int ext4_ext_split(handle_t *handle, struct inode *inode,
631 struct ext4_ext_path *path,
632 struct ext4_extent *newext, int at)
633{
634 struct buffer_head *bh = NULL;
635 int depth = ext_depth(inode);
636 struct ext4_extent_header *neh;
637 struct ext4_extent_idx *fidx;
638 struct ext4_extent *ex;
639 int i = at, k, m, a;
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700640 ext4_fsblk_t newblock, oldblock;
Alex Tomasa86c6182006-10-11 01:21:03 -0700641 __le32 border;
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700642 ext4_fsblk_t *ablocks = NULL; /* array of allocated blocks */
Alex Tomasa86c6182006-10-11 01:21:03 -0700643 int err = 0;
644
645 /* make decision: where to split? */
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700646 /* FIXME: now decision is simplest: at current extent */
Alex Tomasa86c6182006-10-11 01:21:03 -0700647
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700648 /* if current leaf will be split, then we should use
Alex Tomasa86c6182006-10-11 01:21:03 -0700649 * border from split point */
650 BUG_ON(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr));
651 if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
652 border = path[depth].p_ext[1].ee_block;
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700653 ext_debug("leaf will be split."
Alex Tomasa86c6182006-10-11 01:21:03 -0700654 " next leaf starts at %d\n",
Dave Kleikamp8c55e202007-05-24 13:04:54 -0400655 le32_to_cpu(border));
Alex Tomasa86c6182006-10-11 01:21:03 -0700656 } else {
657 border = newext->ee_block;
658 ext_debug("leaf will be added."
659 " next leaf starts at %d\n",
Dave Kleikamp8c55e202007-05-24 13:04:54 -0400660 le32_to_cpu(border));
Alex Tomasa86c6182006-10-11 01:21:03 -0700661 }
662
663 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700664 * If error occurs, then we break processing
665 * and mark filesystem read-only. index won't
Alex Tomasa86c6182006-10-11 01:21:03 -0700666 * be inserted and tree will be in consistent
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700667 * state. Next mount will repair buffers too.
Alex Tomasa86c6182006-10-11 01:21:03 -0700668 */
669
670 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700671 * Get array to track all allocated blocks.
672 * We need this to handle errors and free blocks
673 * upon them.
Alex Tomasa86c6182006-10-11 01:21:03 -0700674 */
Avantika Mathur5d4958f2006-12-06 20:41:35 -0800675 ablocks = kzalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
Alex Tomasa86c6182006-10-11 01:21:03 -0700676 if (!ablocks)
677 return -ENOMEM;
Alex Tomasa86c6182006-10-11 01:21:03 -0700678
679 /* allocate all needed blocks */
680 ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
681 for (a = 0; a < depth - at; a++) {
682 newblock = ext4_ext_new_block(handle, inode, path, newext, &err);
683 if (newblock == 0)
684 goto cleanup;
685 ablocks[a] = newblock;
686 }
687
688 /* initialize new leaf */
689 newblock = ablocks[--a];
690 BUG_ON(newblock == 0);
691 bh = sb_getblk(inode->i_sb, newblock);
692 if (!bh) {
693 err = -EIO;
694 goto cleanup;
695 }
696 lock_buffer(bh);
697
Avantika Mathur7e028972006-12-06 20:41:33 -0800698 err = ext4_journal_get_create_access(handle, bh);
699 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -0700700 goto cleanup;
701
702 neh = ext_block_hdr(bh);
703 neh->eh_entries = 0;
704 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode));
705 neh->eh_magic = EXT4_EXT_MAGIC;
706 neh->eh_depth = 0;
707 ex = EXT_FIRST_EXTENT(neh);
708
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700709 /* move remainder of path[depth] to the new leaf */
Alex Tomasa86c6182006-10-11 01:21:03 -0700710 BUG_ON(path[depth].p_hdr->eh_entries != path[depth].p_hdr->eh_max);
711 /* start copy from next extent */
712 /* TODO: we could do it by single memmove */
713 m = 0;
714 path[depth].p_ext++;
715 while (path[depth].p_ext <=
716 EXT_MAX_EXTENT(path[depth].p_hdr)) {
Mingming Cao2ae02102006-10-11 01:21:11 -0700717 ext_debug("move %d:%llu:%d in new leaf %llu\n",
Dave Kleikamp8c55e202007-05-24 13:04:54 -0400718 le32_to_cpu(path[depth].p_ext->ee_block),
719 ext_pblock(path[depth].p_ext),
Amit Aroraa2df2a62007-07-17 21:42:41 -0400720 ext4_ext_get_actual_len(path[depth].p_ext),
Alex Tomasa86c6182006-10-11 01:21:03 -0700721 newblock);
722 /*memmove(ex++, path[depth].p_ext++,
723 sizeof(struct ext4_extent));
724 neh->eh_entries++;*/
725 path[depth].p_ext++;
726 m++;
727 }
728 if (m) {
729 memmove(ex, path[depth].p_ext-m, sizeof(struct ext4_extent)*m);
730 neh->eh_entries = cpu_to_le16(le16_to_cpu(neh->eh_entries)+m);
731 }
732
733 set_buffer_uptodate(bh);
734 unlock_buffer(bh);
735
Avantika Mathur7e028972006-12-06 20:41:33 -0800736 err = ext4_journal_dirty_metadata(handle, bh);
737 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -0700738 goto cleanup;
739 brelse(bh);
740 bh = NULL;
741
742 /* correct old leaf */
743 if (m) {
Avantika Mathur7e028972006-12-06 20:41:33 -0800744 err = ext4_ext_get_access(handle, inode, path + depth);
745 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -0700746 goto cleanup;
747 path[depth].p_hdr->eh_entries =
748 cpu_to_le16(le16_to_cpu(path[depth].p_hdr->eh_entries)-m);
Avantika Mathur7e028972006-12-06 20:41:33 -0800749 err = ext4_ext_dirty(handle, inode, path + depth);
750 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -0700751 goto cleanup;
752
753 }
754
755 /* create intermediate indexes */
756 k = depth - at - 1;
757 BUG_ON(k < 0);
758 if (k)
759 ext_debug("create %d intermediate indices\n", k);
760 /* insert new index into current index block */
761 /* current depth stored in i var */
762 i = depth - 1;
763 while (k--) {
764 oldblock = newblock;
765 newblock = ablocks[--a];
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700766 bh = sb_getblk(inode->i_sb, (ext4_fsblk_t)newblock);
Alex Tomasa86c6182006-10-11 01:21:03 -0700767 if (!bh) {
768 err = -EIO;
769 goto cleanup;
770 }
771 lock_buffer(bh);
772
Avantika Mathur7e028972006-12-06 20:41:33 -0800773 err = ext4_journal_get_create_access(handle, bh);
774 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -0700775 goto cleanup;
776
777 neh = ext_block_hdr(bh);
778 neh->eh_entries = cpu_to_le16(1);
779 neh->eh_magic = EXT4_EXT_MAGIC;
780 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode));
781 neh->eh_depth = cpu_to_le16(depth - i);
782 fidx = EXT_FIRST_INDEX(neh);
783 fidx->ei_block = border;
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700784 ext4_idx_store_pblock(fidx, oldblock);
Alex Tomasa86c6182006-10-11 01:21:03 -0700785
Mingming Cao2ae02102006-10-11 01:21:11 -0700786 ext_debug("int.index at %d (block %llu): %lu -> %llu\n", i,
Alex Tomasa86c6182006-10-11 01:21:03 -0700787 newblock, (unsigned long) le32_to_cpu(border),
788 oldblock);
789 /* copy indexes */
790 m = 0;
791 path[i].p_idx++;
792
793 ext_debug("cur 0x%p, last 0x%p\n", path[i].p_idx,
794 EXT_MAX_INDEX(path[i].p_hdr));
795 BUG_ON(EXT_MAX_INDEX(path[i].p_hdr) !=
796 EXT_LAST_INDEX(path[i].p_hdr));
797 while (path[i].p_idx <= EXT_MAX_INDEX(path[i].p_hdr)) {
Dmitry Monakhov26d535e2007-07-18 08:33:37 -0400798 ext_debug("%d: move %d:%llu in new index %llu\n", i,
Dave Kleikamp8c55e202007-05-24 13:04:54 -0400799 le32_to_cpu(path[i].p_idx->ei_block),
800 idx_pblock(path[i].p_idx),
801 newblock);
Alex Tomasa86c6182006-10-11 01:21:03 -0700802 /*memmove(++fidx, path[i].p_idx++,
803 sizeof(struct ext4_extent_idx));
804 neh->eh_entries++;
805 BUG_ON(neh->eh_entries > neh->eh_max);*/
806 path[i].p_idx++;
807 m++;
808 }
809 if (m) {
810 memmove(++fidx, path[i].p_idx - m,
811 sizeof(struct ext4_extent_idx) * m);
812 neh->eh_entries =
813 cpu_to_le16(le16_to_cpu(neh->eh_entries) + m);
814 }
815 set_buffer_uptodate(bh);
816 unlock_buffer(bh);
817
Avantika Mathur7e028972006-12-06 20:41:33 -0800818 err = ext4_journal_dirty_metadata(handle, bh);
819 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -0700820 goto cleanup;
821 brelse(bh);
822 bh = NULL;
823
824 /* correct old index */
825 if (m) {
826 err = ext4_ext_get_access(handle, inode, path + i);
827 if (err)
828 goto cleanup;
829 path[i].p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path[i].p_hdr->eh_entries)-m);
830 err = ext4_ext_dirty(handle, inode, path + i);
831 if (err)
832 goto cleanup;
833 }
834
835 i--;
836 }
837
838 /* insert new index */
Alex Tomasa86c6182006-10-11 01:21:03 -0700839 err = ext4_ext_insert_index(handle, inode, path + at,
840 le32_to_cpu(border), newblock);
841
842cleanup:
843 if (bh) {
844 if (buffer_locked(bh))
845 unlock_buffer(bh);
846 brelse(bh);
847 }
848
849 if (err) {
850 /* free all allocated blocks in error case */
851 for (i = 0; i < depth; i++) {
852 if (!ablocks[i])
853 continue;
854 ext4_free_blocks(handle, inode, ablocks[i], 1);
855 }
856 }
857 kfree(ablocks);
858
859 return err;
860}
861
862/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700863 * ext4_ext_grow_indepth:
864 * implements tree growing procedure:
865 * - allocates new block
866 * - moves top-level data (index block or leaf) into the new block
867 * - initializes new top-level, creating index that points to the
868 * just created block
Alex Tomasa86c6182006-10-11 01:21:03 -0700869 */
870static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
871 struct ext4_ext_path *path,
872 struct ext4_extent *newext)
873{
874 struct ext4_ext_path *curp = path;
875 struct ext4_extent_header *neh;
876 struct ext4_extent_idx *fidx;
877 struct buffer_head *bh;
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700878 ext4_fsblk_t newblock;
Alex Tomasa86c6182006-10-11 01:21:03 -0700879 int err = 0;
880
881 newblock = ext4_ext_new_block(handle, inode, path, newext, &err);
882 if (newblock == 0)
883 return err;
884
885 bh = sb_getblk(inode->i_sb, newblock);
886 if (!bh) {
887 err = -EIO;
888 ext4_std_error(inode->i_sb, err);
889 return err;
890 }
891 lock_buffer(bh);
892
Avantika Mathur7e028972006-12-06 20:41:33 -0800893 err = ext4_journal_get_create_access(handle, bh);
894 if (err) {
Alex Tomasa86c6182006-10-11 01:21:03 -0700895 unlock_buffer(bh);
896 goto out;
897 }
898
899 /* move top-level index/leaf into new block */
900 memmove(bh->b_data, curp->p_hdr, sizeof(EXT4_I(inode)->i_data));
901
902 /* set size of new block */
903 neh = ext_block_hdr(bh);
904 /* old root could have indexes or leaves
905 * so calculate e_max right way */
906 if (ext_depth(inode))
907 neh->eh_max = cpu_to_le16(ext4_ext_space_block_idx(inode));
908 else
909 neh->eh_max = cpu_to_le16(ext4_ext_space_block(inode));
910 neh->eh_magic = EXT4_EXT_MAGIC;
911 set_buffer_uptodate(bh);
912 unlock_buffer(bh);
913
Avantika Mathur7e028972006-12-06 20:41:33 -0800914 err = ext4_journal_dirty_metadata(handle, bh);
915 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -0700916 goto out;
917
918 /* create index in new top-level index: num,max,pointer */
Avantika Mathur7e028972006-12-06 20:41:33 -0800919 err = ext4_ext_get_access(handle, inode, curp);
920 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -0700921 goto out;
922
923 curp->p_hdr->eh_magic = EXT4_EXT_MAGIC;
924 curp->p_hdr->eh_max = cpu_to_le16(ext4_ext_space_root_idx(inode));
925 curp->p_hdr->eh_entries = cpu_to_le16(1);
926 curp->p_idx = EXT_FIRST_INDEX(curp->p_hdr);
Dmitry Monakhove9f410b2007-07-18 09:09:15 -0400927
928 if (path[0].p_hdr->eh_depth)
929 curp->p_idx->ei_block =
930 EXT_FIRST_INDEX(path[0].p_hdr)->ei_block;
931 else
932 curp->p_idx->ei_block =
933 EXT_FIRST_EXTENT(path[0].p_hdr)->ee_block;
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700934 ext4_idx_store_pblock(curp->p_idx, newblock);
Alex Tomasa86c6182006-10-11 01:21:03 -0700935
936 neh = ext_inode_hdr(inode);
937 fidx = EXT_FIRST_INDEX(neh);
Mingming Cao2ae02102006-10-11 01:21:11 -0700938 ext_debug("new root: num %d(%d), lblock %d, ptr %llu\n",
Alex Tomasa86c6182006-10-11 01:21:03 -0700939 le16_to_cpu(neh->eh_entries), le16_to_cpu(neh->eh_max),
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700940 le32_to_cpu(fidx->ei_block), idx_pblock(fidx));
Alex Tomasa86c6182006-10-11 01:21:03 -0700941
942 neh->eh_depth = cpu_to_le16(path->p_depth + 1);
943 err = ext4_ext_dirty(handle, inode, curp);
944out:
945 brelse(bh);
946
947 return err;
948}
949
950/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700951 * ext4_ext_create_new_leaf:
952 * finds empty index and adds new leaf.
953 * if no free index is found, then it requests in-depth growing.
Alex Tomasa86c6182006-10-11 01:21:03 -0700954 */
955static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
956 struct ext4_ext_path *path,
957 struct ext4_extent *newext)
958{
959 struct ext4_ext_path *curp;
960 int depth, i, err = 0;
961
962repeat:
963 i = depth = ext_depth(inode);
964
965 /* walk up to the tree and look for free index entry */
966 curp = path + depth;
967 while (i > 0 && !EXT_HAS_FREE_INDEX(curp)) {
968 i--;
969 curp--;
970 }
971
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700972 /* we use already allocated block for index block,
973 * so subsequent data blocks should be contiguous */
Alex Tomasa86c6182006-10-11 01:21:03 -0700974 if (EXT_HAS_FREE_INDEX(curp)) {
975 /* if we found index with free entry, then use that
976 * entry: create all needed subtree and add new leaf */
977 err = ext4_ext_split(handle, inode, path, newext, i);
978
979 /* refill path */
980 ext4_ext_drop_refs(path);
981 path = ext4_ext_find_extent(inode,
982 le32_to_cpu(newext->ee_block),
983 path);
984 if (IS_ERR(path))
985 err = PTR_ERR(path);
986 } else {
987 /* tree is full, time to grow in depth */
988 err = ext4_ext_grow_indepth(handle, inode, path, newext);
989 if (err)
990 goto out;
991
992 /* refill path */
993 ext4_ext_drop_refs(path);
994 path = ext4_ext_find_extent(inode,
995 le32_to_cpu(newext->ee_block),
996 path);
997 if (IS_ERR(path)) {
998 err = PTR_ERR(path);
999 goto out;
1000 }
1001
1002 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001003 * only first (depth 0 -> 1) produces free space;
1004 * in all other cases we have to split the grown tree
Alex Tomasa86c6182006-10-11 01:21:03 -07001005 */
1006 depth = ext_depth(inode);
1007 if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001008 /* now we need to split */
Alex Tomasa86c6182006-10-11 01:21:03 -07001009 goto repeat;
1010 }
1011 }
1012
1013out:
1014 return err;
1015}
1016
1017/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001018 * ext4_ext_next_allocated_block:
1019 * returns allocated block in subsequent extent or EXT_MAX_BLOCK.
1020 * NOTE: it considers block number from index entry as
1021 * allocated block. Thus, index entries have to be consistent
1022 * with leaves.
Alex Tomasa86c6182006-10-11 01:21:03 -07001023 */
1024static unsigned long
1025ext4_ext_next_allocated_block(struct ext4_ext_path *path)
1026{
1027 int depth;
1028
1029 BUG_ON(path == NULL);
1030 depth = path->p_depth;
1031
1032 if (depth == 0 && path->p_ext == NULL)
1033 return EXT_MAX_BLOCK;
1034
1035 while (depth >= 0) {
1036 if (depth == path->p_depth) {
1037 /* leaf */
1038 if (path[depth].p_ext !=
1039 EXT_LAST_EXTENT(path[depth].p_hdr))
1040 return le32_to_cpu(path[depth].p_ext[1].ee_block);
1041 } else {
1042 /* index */
1043 if (path[depth].p_idx !=
1044 EXT_LAST_INDEX(path[depth].p_hdr))
1045 return le32_to_cpu(path[depth].p_idx[1].ei_block);
1046 }
1047 depth--;
1048 }
1049
1050 return EXT_MAX_BLOCK;
1051}
1052
1053/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001054 * ext4_ext_next_leaf_block:
Alex Tomasa86c6182006-10-11 01:21:03 -07001055 * returns first allocated block from next leaf or EXT_MAX_BLOCK
1056 */
1057static unsigned ext4_ext_next_leaf_block(struct inode *inode,
Andrew Morton63f57932006-10-11 01:21:24 -07001058 struct ext4_ext_path *path)
Alex Tomasa86c6182006-10-11 01:21:03 -07001059{
1060 int depth;
1061
1062 BUG_ON(path == NULL);
1063 depth = path->p_depth;
1064
1065 /* zero-tree has no leaf blocks at all */
1066 if (depth == 0)
1067 return EXT_MAX_BLOCK;
1068
1069 /* go to index block */
1070 depth--;
1071
1072 while (depth >= 0) {
1073 if (path[depth].p_idx !=
1074 EXT_LAST_INDEX(path[depth].p_hdr))
1075 return le32_to_cpu(path[depth].p_idx[1].ei_block);
1076 depth--;
1077 }
1078
1079 return EXT_MAX_BLOCK;
1080}
1081
1082/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001083 * ext4_ext_correct_indexes:
1084 * if leaf gets modified and modified extent is first in the leaf,
1085 * then we have to correct all indexes above.
Alex Tomasa86c6182006-10-11 01:21:03 -07001086 * TODO: do we need to correct tree in all cases?
1087 */
1088int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
1089 struct ext4_ext_path *path)
1090{
1091 struct ext4_extent_header *eh;
1092 int depth = ext_depth(inode);
1093 struct ext4_extent *ex;
1094 __le32 border;
1095 int k, err = 0;
1096
1097 eh = path[depth].p_hdr;
1098 ex = path[depth].p_ext;
1099 BUG_ON(ex == NULL);
1100 BUG_ON(eh == NULL);
1101
1102 if (depth == 0) {
1103 /* there is no tree at all */
1104 return 0;
1105 }
1106
1107 if (ex != EXT_FIRST_EXTENT(eh)) {
1108 /* we correct tree if first leaf got modified only */
1109 return 0;
1110 }
1111
1112 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001113 * TODO: we need correction if border is smaller than current one
Alex Tomasa86c6182006-10-11 01:21:03 -07001114 */
1115 k = depth - 1;
1116 border = path[depth].p_ext->ee_block;
Avantika Mathur7e028972006-12-06 20:41:33 -08001117 err = ext4_ext_get_access(handle, inode, path + k);
1118 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -07001119 return err;
1120 path[k].p_idx->ei_block = border;
Avantika Mathur7e028972006-12-06 20:41:33 -08001121 err = ext4_ext_dirty(handle, inode, path + k);
1122 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -07001123 return err;
1124
1125 while (k--) {
1126 /* change all left-side indexes */
1127 if (path[k+1].p_idx != EXT_FIRST_INDEX(path[k+1].p_hdr))
1128 break;
Avantika Mathur7e028972006-12-06 20:41:33 -08001129 err = ext4_ext_get_access(handle, inode, path + k);
1130 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -07001131 break;
1132 path[k].p_idx->ei_block = border;
Avantika Mathur7e028972006-12-06 20:41:33 -08001133 err = ext4_ext_dirty(handle, inode, path + k);
1134 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -07001135 break;
1136 }
1137
1138 return err;
1139}
1140
Avantika Mathur09b88252006-12-06 20:41:36 -08001141static int
Alex Tomasa86c6182006-10-11 01:21:03 -07001142ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
1143 struct ext4_extent *ex2)
1144{
Amit Arora749269f2007-07-18 09:02:56 -04001145 unsigned short ext1_ee_len, ext2_ee_len, max_len;
Amit Aroraa2df2a62007-07-17 21:42:41 -04001146
1147 /*
1148 * Make sure that either both extents are uninitialized, or
1149 * both are _not_.
1150 */
1151 if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2))
1152 return 0;
1153
Amit Arora749269f2007-07-18 09:02:56 -04001154 if (ext4_ext_is_uninitialized(ex1))
1155 max_len = EXT_UNINIT_MAX_LEN;
1156 else
1157 max_len = EXT_INIT_MAX_LEN;
1158
Amit Aroraa2df2a62007-07-17 21:42:41 -04001159 ext1_ee_len = ext4_ext_get_actual_len(ex1);
1160 ext2_ee_len = ext4_ext_get_actual_len(ex2);
1161
1162 if (le32_to_cpu(ex1->ee_block) + ext1_ee_len !=
Andrew Morton63f57932006-10-11 01:21:24 -07001163 le32_to_cpu(ex2->ee_block))
Alex Tomasa86c6182006-10-11 01:21:03 -07001164 return 0;
1165
Suparna Bhattacharya471d4012006-10-11 01:21:06 -07001166 /*
1167 * To allow future support for preallocated extents to be added
1168 * as an RO_COMPAT feature, refuse to merge to extents if
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001169 * this can result in the top bit of ee_len being set.
Suparna Bhattacharya471d4012006-10-11 01:21:06 -07001170 */
Amit Arora749269f2007-07-18 09:02:56 -04001171 if (ext1_ee_len + ext2_ee_len > max_len)
Suparna Bhattacharya471d4012006-10-11 01:21:06 -07001172 return 0;
Robert P. J. Daybbf2f9f2007-02-17 19:20:16 +01001173#ifdef AGGRESSIVE_TEST
Alex Tomasa86c6182006-10-11 01:21:03 -07001174 if (le16_to_cpu(ex1->ee_len) >= 4)
1175 return 0;
1176#endif
1177
Amit Aroraa2df2a62007-07-17 21:42:41 -04001178 if (ext_pblock(ex1) + ext1_ee_len == ext_pblock(ex2))
Alex Tomasa86c6182006-10-11 01:21:03 -07001179 return 1;
1180 return 0;
1181}
1182
1183/*
Amit Arora56055d32007-07-17 21:42:38 -04001184 * This function tries to merge the "ex" extent to the next extent in the tree.
1185 * It always tries to merge towards right. If you want to merge towards
1186 * left, pass "ex - 1" as argument instead of "ex".
1187 * Returns 0 if the extents (ex and ex+1) were _not_ merged and returns
1188 * 1 if they got merged.
1189 */
1190int ext4_ext_try_to_merge(struct inode *inode,
1191 struct ext4_ext_path *path,
1192 struct ext4_extent *ex)
1193{
1194 struct ext4_extent_header *eh;
1195 unsigned int depth, len;
1196 int merge_done = 0;
1197 int uninitialized = 0;
1198
1199 depth = ext_depth(inode);
1200 BUG_ON(path[depth].p_hdr == NULL);
1201 eh = path[depth].p_hdr;
1202
1203 while (ex < EXT_LAST_EXTENT(eh)) {
1204 if (!ext4_can_extents_be_merged(inode, ex, ex + 1))
1205 break;
1206 /* merge with next extent! */
1207 if (ext4_ext_is_uninitialized(ex))
1208 uninitialized = 1;
1209 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1210 + ext4_ext_get_actual_len(ex + 1));
1211 if (uninitialized)
1212 ext4_ext_mark_uninitialized(ex);
1213
1214 if (ex + 1 < EXT_LAST_EXTENT(eh)) {
1215 len = (EXT_LAST_EXTENT(eh) - ex - 1)
1216 * sizeof(struct ext4_extent);
1217 memmove(ex + 1, ex + 2, len);
1218 }
1219 eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries) - 1);
1220 merge_done = 1;
1221 WARN_ON(eh->eh_entries == 0);
1222 if (!eh->eh_entries)
1223 ext4_error(inode->i_sb, "ext4_ext_try_to_merge",
1224 "inode#%lu, eh->eh_entries = 0!", inode->i_ino);
1225 }
1226
1227 return merge_done;
1228}
1229
1230/*
Amit Arora25d14f92007-05-24 13:04:13 -04001231 * check if a portion of the "newext" extent overlaps with an
1232 * existing extent.
1233 *
1234 * If there is an overlap discovered, it updates the length of the newext
1235 * such that there will be no overlap, and then returns 1.
1236 * If there is no overlap found, it returns 0.
1237 */
1238unsigned int ext4_ext_check_overlap(struct inode *inode,
1239 struct ext4_extent *newext,
1240 struct ext4_ext_path *path)
1241{
1242 unsigned long b1, b2;
1243 unsigned int depth, len1;
1244 unsigned int ret = 0;
1245
1246 b1 = le32_to_cpu(newext->ee_block);
Amit Aroraa2df2a62007-07-17 21:42:41 -04001247 len1 = ext4_ext_get_actual_len(newext);
Amit Arora25d14f92007-05-24 13:04:13 -04001248 depth = ext_depth(inode);
1249 if (!path[depth].p_ext)
1250 goto out;
1251 b2 = le32_to_cpu(path[depth].p_ext->ee_block);
1252
1253 /*
1254 * get the next allocated block if the extent in the path
1255 * is before the requested block(s)
1256 */
1257 if (b2 < b1) {
1258 b2 = ext4_ext_next_allocated_block(path);
1259 if (b2 == EXT_MAX_BLOCK)
1260 goto out;
1261 }
1262
1263 /* check for wrap through zero */
1264 if (b1 + len1 < b1) {
1265 len1 = EXT_MAX_BLOCK - b1;
1266 newext->ee_len = cpu_to_le16(len1);
1267 ret = 1;
1268 }
1269
1270 /* check for overlap */
1271 if (b1 + len1 > b2) {
1272 newext->ee_len = cpu_to_le16(b2 - b1);
1273 ret = 1;
1274 }
1275out:
1276 return ret;
1277}
1278
1279/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001280 * ext4_ext_insert_extent:
1281 * tries to merge requsted extent into the existing extent or
1282 * inserts requested extent as new one into the tree,
1283 * creating new leaf in the no-space case.
Alex Tomasa86c6182006-10-11 01:21:03 -07001284 */
1285int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
1286 struct ext4_ext_path *path,
1287 struct ext4_extent *newext)
1288{
1289 struct ext4_extent_header * eh;
1290 struct ext4_extent *ex, *fex;
1291 struct ext4_extent *nearex; /* nearest extent */
1292 struct ext4_ext_path *npath = NULL;
1293 int depth, len, err, next;
Amit Aroraa2df2a62007-07-17 21:42:41 -04001294 unsigned uninitialized = 0;
Alex Tomasa86c6182006-10-11 01:21:03 -07001295
Amit Aroraa2df2a62007-07-17 21:42:41 -04001296 BUG_ON(ext4_ext_get_actual_len(newext) == 0);
Alex Tomasa86c6182006-10-11 01:21:03 -07001297 depth = ext_depth(inode);
1298 ex = path[depth].p_ext;
1299 BUG_ON(path[depth].p_hdr == NULL);
1300
1301 /* try to insert block into found extent and return */
1302 if (ex && ext4_can_extents_be_merged(inode, ex, newext)) {
Mingming Cao2ae02102006-10-11 01:21:11 -07001303 ext_debug("append %d block to %d:%d (from %llu)\n",
Amit Aroraa2df2a62007-07-17 21:42:41 -04001304 ext4_ext_get_actual_len(newext),
Alex Tomasa86c6182006-10-11 01:21:03 -07001305 le32_to_cpu(ex->ee_block),
Amit Aroraa2df2a62007-07-17 21:42:41 -04001306 ext4_ext_get_actual_len(ex), ext_pblock(ex));
Avantika Mathur7e028972006-12-06 20:41:33 -08001307 err = ext4_ext_get_access(handle, inode, path + depth);
1308 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -07001309 return err;
Amit Aroraa2df2a62007-07-17 21:42:41 -04001310
1311 /*
1312 * ext4_can_extents_be_merged should have checked that either
1313 * both extents are uninitialized, or both aren't. Thus we
1314 * need to check only one of them here.
1315 */
1316 if (ext4_ext_is_uninitialized(ex))
1317 uninitialized = 1;
1318 ex->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ex)
1319 + ext4_ext_get_actual_len(newext));
1320 if (uninitialized)
1321 ext4_ext_mark_uninitialized(ex);
Alex Tomasa86c6182006-10-11 01:21:03 -07001322 eh = path[depth].p_hdr;
1323 nearex = ex;
1324 goto merge;
1325 }
1326
1327repeat:
1328 depth = ext_depth(inode);
1329 eh = path[depth].p_hdr;
1330 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max))
1331 goto has_space;
1332
1333 /* probably next leaf has space for us? */
1334 fex = EXT_LAST_EXTENT(eh);
1335 next = ext4_ext_next_leaf_block(inode, path);
1336 if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block)
1337 && next != EXT_MAX_BLOCK) {
1338 ext_debug("next leaf block - %d\n", next);
1339 BUG_ON(npath != NULL);
1340 npath = ext4_ext_find_extent(inode, next, NULL);
1341 if (IS_ERR(npath))
1342 return PTR_ERR(npath);
1343 BUG_ON(npath->p_depth != path->p_depth);
1344 eh = npath[depth].p_hdr;
1345 if (le16_to_cpu(eh->eh_entries) < le16_to_cpu(eh->eh_max)) {
1346 ext_debug("next leaf isnt full(%d)\n",
1347 le16_to_cpu(eh->eh_entries));
1348 path = npath;
1349 goto repeat;
1350 }
1351 ext_debug("next leaf has no free space(%d,%d)\n",
1352 le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max));
1353 }
1354
1355 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001356 * There is no free space in the found leaf.
1357 * We're gonna add a new leaf in the tree.
Alex Tomasa86c6182006-10-11 01:21:03 -07001358 */
1359 err = ext4_ext_create_new_leaf(handle, inode, path, newext);
1360 if (err)
1361 goto cleanup;
1362 depth = ext_depth(inode);
1363 eh = path[depth].p_hdr;
1364
1365has_space:
1366 nearex = path[depth].p_ext;
1367
Avantika Mathur7e028972006-12-06 20:41:33 -08001368 err = ext4_ext_get_access(handle, inode, path + depth);
1369 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -07001370 goto cleanup;
1371
1372 if (!nearex) {
1373 /* there is no extent in this leaf, create first one */
Mingming Cao2ae02102006-10-11 01:21:11 -07001374 ext_debug("first extent in the leaf: %d:%llu:%d\n",
Dave Kleikamp8c55e202007-05-24 13:04:54 -04001375 le32_to_cpu(newext->ee_block),
1376 ext_pblock(newext),
Amit Aroraa2df2a62007-07-17 21:42:41 -04001377 ext4_ext_get_actual_len(newext));
Alex Tomasa86c6182006-10-11 01:21:03 -07001378 path[depth].p_ext = EXT_FIRST_EXTENT(eh);
1379 } else if (le32_to_cpu(newext->ee_block)
Dave Kleikamp8c55e202007-05-24 13:04:54 -04001380 > le32_to_cpu(nearex->ee_block)) {
Alex Tomasa86c6182006-10-11 01:21:03 -07001381/* BUG_ON(newext->ee_block == nearex->ee_block); */
1382 if (nearex != EXT_LAST_EXTENT(eh)) {
1383 len = EXT_MAX_EXTENT(eh) - nearex;
1384 len = (len - 1) * sizeof(struct ext4_extent);
1385 len = len < 0 ? 0 : len;
Mingming Cao2ae02102006-10-11 01:21:11 -07001386 ext_debug("insert %d:%llu:%d after: nearest 0x%p, "
Alex Tomasa86c6182006-10-11 01:21:03 -07001387 "move %d from 0x%p to 0x%p\n",
Dave Kleikamp8c55e202007-05-24 13:04:54 -04001388 le32_to_cpu(newext->ee_block),
1389 ext_pblock(newext),
Amit Aroraa2df2a62007-07-17 21:42:41 -04001390 ext4_ext_get_actual_len(newext),
Alex Tomasa86c6182006-10-11 01:21:03 -07001391 nearex, len, nearex + 1, nearex + 2);
1392 memmove(nearex + 2, nearex + 1, len);
1393 }
1394 path[depth].p_ext = nearex + 1;
1395 } else {
1396 BUG_ON(newext->ee_block == nearex->ee_block);
1397 len = (EXT_MAX_EXTENT(eh) - nearex) * sizeof(struct ext4_extent);
1398 len = len < 0 ? 0 : len;
Mingming Cao2ae02102006-10-11 01:21:11 -07001399 ext_debug("insert %d:%llu:%d before: nearest 0x%p, "
Alex Tomasa86c6182006-10-11 01:21:03 -07001400 "move %d from 0x%p to 0x%p\n",
1401 le32_to_cpu(newext->ee_block),
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001402 ext_pblock(newext),
Amit Aroraa2df2a62007-07-17 21:42:41 -04001403 ext4_ext_get_actual_len(newext),
Alex Tomasa86c6182006-10-11 01:21:03 -07001404 nearex, len, nearex + 1, nearex + 2);
1405 memmove(nearex + 1, nearex, len);
1406 path[depth].p_ext = nearex;
1407 }
1408
1409 eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)+1);
1410 nearex = path[depth].p_ext;
1411 nearex->ee_block = newext->ee_block;
Aneesh Kumar K.Vb3776112007-10-16 18:38:25 -04001412 ext4_ext_store_pblock(nearex, ext_pblock(newext));
Alex Tomasa86c6182006-10-11 01:21:03 -07001413 nearex->ee_len = newext->ee_len;
Alex Tomasa86c6182006-10-11 01:21:03 -07001414
1415merge:
1416 /* try to merge extents to the right */
Amit Arora56055d32007-07-17 21:42:38 -04001417 ext4_ext_try_to_merge(inode, path, nearex);
Alex Tomasa86c6182006-10-11 01:21:03 -07001418
1419 /* try to merge extents to the left */
1420
1421 /* time to correct all indexes above */
1422 err = ext4_ext_correct_indexes(handle, inode, path);
1423 if (err)
1424 goto cleanup;
1425
1426 err = ext4_ext_dirty(handle, inode, path + depth);
1427
1428cleanup:
1429 if (npath) {
1430 ext4_ext_drop_refs(npath);
1431 kfree(npath);
1432 }
1433 ext4_ext_tree_changed(inode);
1434 ext4_ext_invalidate_cache(inode);
1435 return err;
1436}
1437
1438int ext4_ext_walk_space(struct inode *inode, unsigned long block,
1439 unsigned long num, ext_prepare_callback func,
1440 void *cbdata)
1441{
1442 struct ext4_ext_path *path = NULL;
1443 struct ext4_ext_cache cbex;
1444 struct ext4_extent *ex;
1445 unsigned long next, start = 0, end = 0;
1446 unsigned long last = block + num;
1447 int depth, exists, err = 0;
1448
1449 BUG_ON(func == NULL);
1450 BUG_ON(inode == NULL);
1451
1452 while (block < last && block != EXT_MAX_BLOCK) {
1453 num = last - block;
1454 /* find extent for this block */
1455 path = ext4_ext_find_extent(inode, block, path);
1456 if (IS_ERR(path)) {
1457 err = PTR_ERR(path);
1458 path = NULL;
1459 break;
1460 }
1461
1462 depth = ext_depth(inode);
1463 BUG_ON(path[depth].p_hdr == NULL);
1464 ex = path[depth].p_ext;
1465 next = ext4_ext_next_allocated_block(path);
1466
1467 exists = 0;
1468 if (!ex) {
1469 /* there is no extent yet, so try to allocate
1470 * all requested space */
1471 start = block;
1472 end = block + num;
1473 } else if (le32_to_cpu(ex->ee_block) > block) {
1474 /* need to allocate space before found extent */
1475 start = block;
1476 end = le32_to_cpu(ex->ee_block);
1477 if (block + num < end)
1478 end = block + num;
Amit Aroraa2df2a62007-07-17 21:42:41 -04001479 } else if (block >= le32_to_cpu(ex->ee_block)
1480 + ext4_ext_get_actual_len(ex)) {
Alex Tomasa86c6182006-10-11 01:21:03 -07001481 /* need to allocate space after found extent */
1482 start = block;
1483 end = block + num;
1484 if (end >= next)
1485 end = next;
1486 } else if (block >= le32_to_cpu(ex->ee_block)) {
1487 /*
1488 * some part of requested space is covered
1489 * by found extent
1490 */
1491 start = block;
Amit Aroraa2df2a62007-07-17 21:42:41 -04001492 end = le32_to_cpu(ex->ee_block)
1493 + ext4_ext_get_actual_len(ex);
Alex Tomasa86c6182006-10-11 01:21:03 -07001494 if (block + num < end)
1495 end = block + num;
1496 exists = 1;
1497 } else {
1498 BUG();
1499 }
1500 BUG_ON(end <= start);
1501
1502 if (!exists) {
1503 cbex.ec_block = start;
1504 cbex.ec_len = end - start;
1505 cbex.ec_start = 0;
1506 cbex.ec_type = EXT4_EXT_CACHE_GAP;
1507 } else {
Dave Kleikamp8c55e202007-05-24 13:04:54 -04001508 cbex.ec_block = le32_to_cpu(ex->ee_block);
Amit Aroraa2df2a62007-07-17 21:42:41 -04001509 cbex.ec_len = ext4_ext_get_actual_len(ex);
Dave Kleikamp8c55e202007-05-24 13:04:54 -04001510 cbex.ec_start = ext_pblock(ex);
Alex Tomasa86c6182006-10-11 01:21:03 -07001511 cbex.ec_type = EXT4_EXT_CACHE_EXTENT;
1512 }
1513
1514 BUG_ON(cbex.ec_len == 0);
1515 err = func(inode, path, &cbex, cbdata);
1516 ext4_ext_drop_refs(path);
1517
1518 if (err < 0)
1519 break;
1520 if (err == EXT_REPEAT)
1521 continue;
1522 else if (err == EXT_BREAK) {
1523 err = 0;
1524 break;
1525 }
1526
1527 if (ext_depth(inode) != depth) {
1528 /* depth was changed. we have to realloc path */
1529 kfree(path);
1530 path = NULL;
1531 }
1532
1533 block = cbex.ec_block + cbex.ec_len;
1534 }
1535
1536 if (path) {
1537 ext4_ext_drop_refs(path);
1538 kfree(path);
1539 }
1540
1541 return err;
1542}
1543
Avantika Mathur09b88252006-12-06 20:41:36 -08001544static void
Alex Tomasa86c6182006-10-11 01:21:03 -07001545ext4_ext_put_in_cache(struct inode *inode, __u32 block,
Mingming Caodd545672007-07-31 00:37:46 -07001546 __u32 len, ext4_fsblk_t start, int type)
Alex Tomasa86c6182006-10-11 01:21:03 -07001547{
1548 struct ext4_ext_cache *cex;
1549 BUG_ON(len == 0);
1550 cex = &EXT4_I(inode)->i_cached_extent;
1551 cex->ec_type = type;
1552 cex->ec_block = block;
1553 cex->ec_len = len;
1554 cex->ec_start = start;
1555}
1556
1557/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001558 * ext4_ext_put_gap_in_cache:
1559 * calculate boundaries of the gap that the requested block fits into
Alex Tomasa86c6182006-10-11 01:21:03 -07001560 * and cache this gap
1561 */
Avantika Mathur09b88252006-12-06 20:41:36 -08001562static void
Alex Tomasa86c6182006-10-11 01:21:03 -07001563ext4_ext_put_gap_in_cache(struct inode *inode, struct ext4_ext_path *path,
1564 unsigned long block)
1565{
1566 int depth = ext_depth(inode);
1567 unsigned long lblock, len;
1568 struct ext4_extent *ex;
1569
1570 ex = path[depth].p_ext;
1571 if (ex == NULL) {
1572 /* there is no extent yet, so gap is [0;-] */
1573 lblock = 0;
1574 len = EXT_MAX_BLOCK;
1575 ext_debug("cache gap(whole file):");
1576 } else if (block < le32_to_cpu(ex->ee_block)) {
1577 lblock = block;
1578 len = le32_to_cpu(ex->ee_block) - block;
1579 ext_debug("cache gap(before): %lu [%lu:%lu]",
1580 (unsigned long) block,
Dave Kleikamp8c55e202007-05-24 13:04:54 -04001581 (unsigned long) le32_to_cpu(ex->ee_block),
Amit Aroraa2df2a62007-07-17 21:42:41 -04001582 (unsigned long) ext4_ext_get_actual_len(ex));
Alex Tomasa86c6182006-10-11 01:21:03 -07001583 } else if (block >= le32_to_cpu(ex->ee_block)
Amit Aroraa2df2a62007-07-17 21:42:41 -04001584 + ext4_ext_get_actual_len(ex)) {
Dave Kleikamp8c55e202007-05-24 13:04:54 -04001585 lblock = le32_to_cpu(ex->ee_block)
Amit Aroraa2df2a62007-07-17 21:42:41 -04001586 + ext4_ext_get_actual_len(ex);
Alex Tomasa86c6182006-10-11 01:21:03 -07001587 len = ext4_ext_next_allocated_block(path);
1588 ext_debug("cache gap(after): [%lu:%lu] %lu",
Dave Kleikamp8c55e202007-05-24 13:04:54 -04001589 (unsigned long) le32_to_cpu(ex->ee_block),
Amit Aroraa2df2a62007-07-17 21:42:41 -04001590 (unsigned long) ext4_ext_get_actual_len(ex),
Alex Tomasa86c6182006-10-11 01:21:03 -07001591 (unsigned long) block);
1592 BUG_ON(len == lblock);
1593 len = len - lblock;
1594 } else {
1595 lblock = len = 0;
1596 BUG();
1597 }
1598
1599 ext_debug(" -> %lu:%lu\n", (unsigned long) lblock, len);
1600 ext4_ext_put_in_cache(inode, lblock, len, 0, EXT4_EXT_CACHE_GAP);
1601}
1602
Avantika Mathur09b88252006-12-06 20:41:36 -08001603static int
Alex Tomasa86c6182006-10-11 01:21:03 -07001604ext4_ext_in_cache(struct inode *inode, unsigned long block,
1605 struct ext4_extent *ex)
1606{
1607 struct ext4_ext_cache *cex;
1608
1609 cex = &EXT4_I(inode)->i_cached_extent;
1610
1611 /* has cache valid data? */
1612 if (cex->ec_type == EXT4_EXT_CACHE_NO)
1613 return EXT4_EXT_CACHE_NO;
1614
1615 BUG_ON(cex->ec_type != EXT4_EXT_CACHE_GAP &&
1616 cex->ec_type != EXT4_EXT_CACHE_EXTENT);
1617 if (block >= cex->ec_block && block < cex->ec_block + cex->ec_len) {
Dave Kleikamp8c55e202007-05-24 13:04:54 -04001618 ex->ee_block = cpu_to_le32(cex->ec_block);
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001619 ext4_ext_store_pblock(ex, cex->ec_start);
Dave Kleikamp8c55e202007-05-24 13:04:54 -04001620 ex->ee_len = cpu_to_le16(cex->ec_len);
Mingming Cao2ae02102006-10-11 01:21:11 -07001621 ext_debug("%lu cached by %lu:%lu:%llu\n",
Alex Tomasa86c6182006-10-11 01:21:03 -07001622 (unsigned long) block,
1623 (unsigned long) cex->ec_block,
1624 (unsigned long) cex->ec_len,
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001625 cex->ec_start);
Alex Tomasa86c6182006-10-11 01:21:03 -07001626 return cex->ec_type;
1627 }
1628
1629 /* not in cache */
1630 return EXT4_EXT_CACHE_NO;
1631}
1632
1633/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001634 * ext4_ext_rm_idx:
1635 * removes index from the index block.
1636 * It's used in truncate case only, thus all requests are for
1637 * last index in the block only.
Alex Tomasa86c6182006-10-11 01:21:03 -07001638 */
1639int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
1640 struct ext4_ext_path *path)
1641{
1642 struct buffer_head *bh;
1643 int err;
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001644 ext4_fsblk_t leaf;
Alex Tomasa86c6182006-10-11 01:21:03 -07001645
1646 /* free index block */
1647 path--;
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001648 leaf = idx_pblock(path->p_idx);
Alex Tomasa86c6182006-10-11 01:21:03 -07001649 BUG_ON(path->p_hdr->eh_entries == 0);
Avantika Mathur7e028972006-12-06 20:41:33 -08001650 err = ext4_ext_get_access(handle, inode, path);
1651 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -07001652 return err;
1653 path->p_hdr->eh_entries = cpu_to_le16(le16_to_cpu(path->p_hdr->eh_entries)-1);
Avantika Mathur7e028972006-12-06 20:41:33 -08001654 err = ext4_ext_dirty(handle, inode, path);
1655 if (err)
Alex Tomasa86c6182006-10-11 01:21:03 -07001656 return err;
Mingming Cao2ae02102006-10-11 01:21:11 -07001657 ext_debug("index is empty, remove it, free block %llu\n", leaf);
Alex Tomasa86c6182006-10-11 01:21:03 -07001658 bh = sb_find_get_block(inode->i_sb, leaf);
1659 ext4_forget(handle, 1, inode, bh, leaf);
1660 ext4_free_blocks(handle, inode, leaf, 1);
1661 return err;
1662}
1663
1664/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001665 * ext4_ext_calc_credits_for_insert:
1666 * This routine returns max. credits that the extent tree can consume.
Alex Tomasa86c6182006-10-11 01:21:03 -07001667 * It should be OK for low-performance paths like ->writepage()
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001668 * To allow many writing processes to fit into a single transaction,
1669 * the caller should calculate credits under truncate_mutex and
1670 * pass the actual path.
Alex Tomasa86c6182006-10-11 01:21:03 -07001671 */
Avantika Mathur09b88252006-12-06 20:41:36 -08001672int ext4_ext_calc_credits_for_insert(struct inode *inode,
Alex Tomasa86c6182006-10-11 01:21:03 -07001673 struct ext4_ext_path *path)
1674{
1675 int depth, needed;
1676
1677 if (path) {
1678 /* probably there is space in leaf? */
1679 depth = ext_depth(inode);
1680 if (le16_to_cpu(path[depth].p_hdr->eh_entries)
1681 < le16_to_cpu(path[depth].p_hdr->eh_max))
1682 return 1;
1683 }
1684
1685 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001686 * given 32-bit logical block (4294967296 blocks), max. tree
Alex Tomasa86c6182006-10-11 01:21:03 -07001687 * can be 4 levels in depth -- 4 * 340^4 == 53453440000.
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001688 * Let's also add one more level for imbalance.
Alex Tomasa86c6182006-10-11 01:21:03 -07001689 */
1690 depth = 5;
1691
1692 /* allocation of new data block(s) */
1693 needed = 2;
1694
1695 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001696 * tree can be full, so it would need to grow in depth:
Johann Lombardifeb18922006-12-06 20:40:46 -08001697 * we need one credit to modify old root, credits for
1698 * new root will be added in split accounting
Alex Tomasa86c6182006-10-11 01:21:03 -07001699 */
Johann Lombardifeb18922006-12-06 20:40:46 -08001700 needed += 1;
Alex Tomasa86c6182006-10-11 01:21:03 -07001701
1702 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001703 * Index split can happen, we would need:
Alex Tomasa86c6182006-10-11 01:21:03 -07001704 * allocate intermediate indexes (bitmap + group)
1705 * + change two blocks at each level, but root (already included)
1706 */
Johann Lombardifeb18922006-12-06 20:40:46 -08001707 needed += (depth * 2) + (depth * 2);
Alex Tomasa86c6182006-10-11 01:21:03 -07001708
1709 /* any allocation modifies superblock */
1710 needed += 1;
1711
1712 return needed;
1713}
1714
1715static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
1716 struct ext4_extent *ex,
1717 unsigned long from, unsigned long to)
1718{
1719 struct buffer_head *bh;
Amit Aroraa2df2a62007-07-17 21:42:41 -04001720 unsigned short ee_len = ext4_ext_get_actual_len(ex);
Alex Tomasa86c6182006-10-11 01:21:03 -07001721 int i;
1722
1723#ifdef EXTENTS_STATS
1724 {
1725 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
Alex Tomasa86c6182006-10-11 01:21:03 -07001726 spin_lock(&sbi->s_ext_stats_lock);
1727 sbi->s_ext_blocks += ee_len;
1728 sbi->s_ext_extents++;
1729 if (ee_len < sbi->s_ext_min)
1730 sbi->s_ext_min = ee_len;
1731 if (ee_len > sbi->s_ext_max)
1732 sbi->s_ext_max = ee_len;
1733 if (ext_depth(inode) > sbi->s_depth_max)
1734 sbi->s_depth_max = ext_depth(inode);
1735 spin_unlock(&sbi->s_ext_stats_lock);
1736 }
1737#endif
1738 if (from >= le32_to_cpu(ex->ee_block)
Amit Aroraa2df2a62007-07-17 21:42:41 -04001739 && to == le32_to_cpu(ex->ee_block) + ee_len - 1) {
Alex Tomasa86c6182006-10-11 01:21:03 -07001740 /* tail removal */
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001741 unsigned long num;
1742 ext4_fsblk_t start;
Amit Aroraa2df2a62007-07-17 21:42:41 -04001743 num = le32_to_cpu(ex->ee_block) + ee_len - from;
1744 start = ext_pblock(ex) + ee_len - num;
Mingming Cao2ae02102006-10-11 01:21:11 -07001745 ext_debug("free last %lu blocks starting %llu\n", num, start);
Alex Tomasa86c6182006-10-11 01:21:03 -07001746 for (i = 0; i < num; i++) {
1747 bh = sb_find_get_block(inode->i_sb, start + i);
1748 ext4_forget(handle, 0, inode, bh, start + i);
1749 }
1750 ext4_free_blocks(handle, inode, start, num);
1751 } else if (from == le32_to_cpu(ex->ee_block)
Amit Aroraa2df2a62007-07-17 21:42:41 -04001752 && to <= le32_to_cpu(ex->ee_block) + ee_len - 1) {
Alex Tomasa86c6182006-10-11 01:21:03 -07001753 printk("strange request: removal %lu-%lu from %u:%u\n",
Amit Aroraa2df2a62007-07-17 21:42:41 -04001754 from, to, le32_to_cpu(ex->ee_block), ee_len);
Alex Tomasa86c6182006-10-11 01:21:03 -07001755 } else {
1756 printk("strange request: removal(2) %lu-%lu from %u:%u\n",
Amit Aroraa2df2a62007-07-17 21:42:41 -04001757 from, to, le32_to_cpu(ex->ee_block), ee_len);
Alex Tomasa86c6182006-10-11 01:21:03 -07001758 }
1759 return 0;
1760}
1761
1762static int
1763ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
1764 struct ext4_ext_path *path, unsigned long start)
1765{
1766 int err = 0, correct_index = 0;
1767 int depth = ext_depth(inode), credits;
1768 struct ext4_extent_header *eh;
1769 unsigned a, b, block, num;
1770 unsigned long ex_ee_block;
1771 unsigned short ex_ee_len;
Amit Aroraa2df2a62007-07-17 21:42:41 -04001772 unsigned uninitialized = 0;
Alex Tomasa86c6182006-10-11 01:21:03 -07001773 struct ext4_extent *ex;
1774
Alex Tomasc29c0ae2007-07-18 09:19:09 -04001775 /* the header must be checked already in ext4_ext_remove_space() */
Alex Tomasa86c6182006-10-11 01:21:03 -07001776 ext_debug("truncate since %lu in leaf\n", start);
1777 if (!path[depth].p_hdr)
1778 path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
1779 eh = path[depth].p_hdr;
1780 BUG_ON(eh == NULL);
Alex Tomasa86c6182006-10-11 01:21:03 -07001781
1782 /* find where to start removing */
1783 ex = EXT_LAST_EXTENT(eh);
1784
1785 ex_ee_block = le32_to_cpu(ex->ee_block);
Amit Aroraa2df2a62007-07-17 21:42:41 -04001786 if (ext4_ext_is_uninitialized(ex))
1787 uninitialized = 1;
1788 ex_ee_len = ext4_ext_get_actual_len(ex);
Alex Tomasa86c6182006-10-11 01:21:03 -07001789
1790 while (ex >= EXT_FIRST_EXTENT(eh) &&
1791 ex_ee_block + ex_ee_len > start) {
1792 ext_debug("remove ext %lu:%u\n", ex_ee_block, ex_ee_len);
1793 path[depth].p_ext = ex;
1794
1795 a = ex_ee_block > start ? ex_ee_block : start;
1796 b = ex_ee_block + ex_ee_len - 1 < EXT_MAX_BLOCK ?
1797 ex_ee_block + ex_ee_len - 1 : EXT_MAX_BLOCK;
1798
1799 ext_debug(" border %u:%u\n", a, b);
1800
1801 if (a != ex_ee_block && b != ex_ee_block + ex_ee_len - 1) {
1802 block = 0;
1803 num = 0;
1804 BUG();
1805 } else if (a != ex_ee_block) {
1806 /* remove tail of the extent */
1807 block = ex_ee_block;
1808 num = a - block;
1809 } else if (b != ex_ee_block + ex_ee_len - 1) {
1810 /* remove head of the extent */
1811 block = a;
1812 num = b - a;
1813 /* there is no "make a hole" API yet */
1814 BUG();
1815 } else {
1816 /* remove whole extent: excellent! */
1817 block = ex_ee_block;
1818 num = 0;
1819 BUG_ON(a != ex_ee_block);
1820 BUG_ON(b != ex_ee_block + ex_ee_len - 1);
1821 }
1822
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001823 /* at present, extent can't cross block group: */
Alex Tomasa86c6182006-10-11 01:21:03 -07001824 /* leaf + bitmap + group desc + sb + inode */
1825 credits = 5;
1826 if (ex == EXT_FIRST_EXTENT(eh)) {
1827 correct_index = 1;
1828 credits += (ext_depth(inode)) + 1;
1829 }
1830#ifdef CONFIG_QUOTA
1831 credits += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
1832#endif
1833
1834 handle = ext4_ext_journal_restart(handle, credits);
1835 if (IS_ERR(handle)) {
1836 err = PTR_ERR(handle);
1837 goto out;
1838 }
1839
1840 err = ext4_ext_get_access(handle, inode, path + depth);
1841 if (err)
1842 goto out;
1843
1844 err = ext4_remove_blocks(handle, inode, ex, a, b);
1845 if (err)
1846 goto out;
1847
1848 if (num == 0) {
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001849 /* this extent is removed; mark slot entirely unused */
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001850 ext4_ext_store_pblock(ex, 0);
Alex Tomasa86c6182006-10-11 01:21:03 -07001851 eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)-1);
1852 }
1853
1854 ex->ee_block = cpu_to_le32(block);
1855 ex->ee_len = cpu_to_le16(num);
Amit Arora749269f2007-07-18 09:02:56 -04001856 /*
1857 * Do not mark uninitialized if all the blocks in the
1858 * extent have been removed.
1859 */
1860 if (uninitialized && num)
Amit Aroraa2df2a62007-07-17 21:42:41 -04001861 ext4_ext_mark_uninitialized(ex);
Alex Tomasa86c6182006-10-11 01:21:03 -07001862
1863 err = ext4_ext_dirty(handle, inode, path + depth);
1864 if (err)
1865 goto out;
1866
Mingming Cao2ae02102006-10-11 01:21:11 -07001867 ext_debug("new extent: %u:%u:%llu\n", block, num,
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001868 ext_pblock(ex));
Alex Tomasa86c6182006-10-11 01:21:03 -07001869 ex--;
1870 ex_ee_block = le32_to_cpu(ex->ee_block);
Amit Aroraa2df2a62007-07-17 21:42:41 -04001871 ex_ee_len = ext4_ext_get_actual_len(ex);
Alex Tomasa86c6182006-10-11 01:21:03 -07001872 }
1873
1874 if (correct_index && eh->eh_entries)
1875 err = ext4_ext_correct_indexes(handle, inode, path);
1876
1877 /* if this leaf is free, then we should
1878 * remove it from index block above */
1879 if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
1880 err = ext4_ext_rm_idx(handle, inode, path + depth);
1881
1882out:
1883 return err;
1884}
1885
1886/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001887 * ext4_ext_more_to_rm:
1888 * returns 1 if current index has to be freed (even partial)
Alex Tomasa86c6182006-10-11 01:21:03 -07001889 */
Avantika Mathur09b88252006-12-06 20:41:36 -08001890static int
Alex Tomasa86c6182006-10-11 01:21:03 -07001891ext4_ext_more_to_rm(struct ext4_ext_path *path)
1892{
1893 BUG_ON(path->p_idx == NULL);
1894
1895 if (path->p_idx < EXT_FIRST_INDEX(path->p_hdr))
1896 return 0;
1897
1898 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001899 * if truncate on deeper level happened, it wasn't partial,
Alex Tomasa86c6182006-10-11 01:21:03 -07001900 * so we have to consider current index for truncation
1901 */
1902 if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
1903 return 0;
1904 return 1;
1905}
1906
1907int ext4_ext_remove_space(struct inode *inode, unsigned long start)
1908{
1909 struct super_block *sb = inode->i_sb;
1910 int depth = ext_depth(inode);
1911 struct ext4_ext_path *path;
1912 handle_t *handle;
1913 int i = 0, err = 0;
1914
1915 ext_debug("truncate since %lu\n", start);
1916
1917 /* probably first extent we're gonna free will be last in block */
1918 handle = ext4_journal_start(inode, depth + 1);
1919 if (IS_ERR(handle))
1920 return PTR_ERR(handle);
1921
1922 ext4_ext_invalidate_cache(inode);
1923
1924 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001925 * We start scanning from right side, freeing all the blocks
1926 * after i_size and walking into the tree depth-wise.
Alex Tomasa86c6182006-10-11 01:21:03 -07001927 */
Avantika Mathur5d4958f2006-12-06 20:41:35 -08001928 path = kzalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_KERNEL);
Alex Tomasa86c6182006-10-11 01:21:03 -07001929 if (path == NULL) {
1930 ext4_journal_stop(handle);
1931 return -ENOMEM;
1932 }
Alex Tomasa86c6182006-10-11 01:21:03 -07001933 path[0].p_hdr = ext_inode_hdr(inode);
Alex Tomasc29c0ae2007-07-18 09:19:09 -04001934 if (ext4_ext_check_header(inode, path[0].p_hdr, depth)) {
Alex Tomasa86c6182006-10-11 01:21:03 -07001935 err = -EIO;
1936 goto out;
1937 }
1938 path[0].p_depth = depth;
1939
1940 while (i >= 0 && err == 0) {
1941 if (i == depth) {
1942 /* this is leaf block */
1943 err = ext4_ext_rm_leaf(handle, inode, path, start);
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001944 /* root level has p_bh == NULL, brelse() eats this */
Alex Tomasa86c6182006-10-11 01:21:03 -07001945 brelse(path[i].p_bh);
1946 path[i].p_bh = NULL;
1947 i--;
1948 continue;
1949 }
1950
1951 /* this is index block */
1952 if (!path[i].p_hdr) {
1953 ext_debug("initialize header\n");
1954 path[i].p_hdr = ext_block_hdr(path[i].p_bh);
Alex Tomasa86c6182006-10-11 01:21:03 -07001955 }
1956
Alex Tomasa86c6182006-10-11 01:21:03 -07001957 if (!path[i].p_idx) {
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001958 /* this level hasn't been touched yet */
Alex Tomasa86c6182006-10-11 01:21:03 -07001959 path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
1960 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
1961 ext_debug("init index ptr: hdr 0x%p, num %d\n",
1962 path[i].p_hdr,
1963 le16_to_cpu(path[i].p_hdr->eh_entries));
1964 } else {
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001965 /* we were already here, see at next index */
Alex Tomasa86c6182006-10-11 01:21:03 -07001966 path[i].p_idx--;
1967 }
1968
1969 ext_debug("level %d - index, first 0x%p, cur 0x%p\n",
1970 i, EXT_FIRST_INDEX(path[i].p_hdr),
1971 path[i].p_idx);
1972 if (ext4_ext_more_to_rm(path + i)) {
Alex Tomasc29c0ae2007-07-18 09:19:09 -04001973 struct buffer_head *bh;
Alex Tomasa86c6182006-10-11 01:21:03 -07001974 /* go to the next level */
Mingming Cao2ae02102006-10-11 01:21:11 -07001975 ext_debug("move to level %d (block %llu)\n",
Alex Tomasf65e6fb2006-10-11 01:21:05 -07001976 i + 1, idx_pblock(path[i].p_idx));
Alex Tomasa86c6182006-10-11 01:21:03 -07001977 memset(path + i + 1, 0, sizeof(*path));
Alex Tomasc29c0ae2007-07-18 09:19:09 -04001978 bh = sb_bread(sb, idx_pblock(path[i].p_idx));
1979 if (!bh) {
Alex Tomasa86c6182006-10-11 01:21:03 -07001980 /* should we reset i_size? */
1981 err = -EIO;
1982 break;
1983 }
Alex Tomasc29c0ae2007-07-18 09:19:09 -04001984 if (WARN_ON(i + 1 > depth)) {
1985 err = -EIO;
1986 break;
1987 }
1988 if (ext4_ext_check_header(inode, ext_block_hdr(bh),
1989 depth - i - 1)) {
1990 err = -EIO;
1991 break;
1992 }
1993 path[i + 1].p_bh = bh;
Alex Tomasa86c6182006-10-11 01:21:03 -07001994
Randy Dunlapd0d856e2006-10-11 01:21:07 -07001995 /* save actual number of indexes since this
1996 * number is changed at the next iteration */
Alex Tomasa86c6182006-10-11 01:21:03 -07001997 path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
1998 i++;
1999 } else {
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002000 /* we finished processing this index, go up */
Alex Tomasa86c6182006-10-11 01:21:03 -07002001 if (path[i].p_hdr->eh_entries == 0 && i > 0) {
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002002 /* index is empty, remove it;
Alex Tomasa86c6182006-10-11 01:21:03 -07002003 * handle must be already prepared by the
2004 * truncatei_leaf() */
2005 err = ext4_ext_rm_idx(handle, inode, path + i);
2006 }
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002007 /* root level has p_bh == NULL, brelse() eats this */
Alex Tomasa86c6182006-10-11 01:21:03 -07002008 brelse(path[i].p_bh);
2009 path[i].p_bh = NULL;
2010 i--;
2011 ext_debug("return to level %d\n", i);
2012 }
2013 }
2014
2015 /* TODO: flexible tree reduction should be here */
2016 if (path->p_hdr->eh_entries == 0) {
2017 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002018 * truncate to zero freed all the tree,
2019 * so we need to correct eh_depth
Alex Tomasa86c6182006-10-11 01:21:03 -07002020 */
2021 err = ext4_ext_get_access(handle, inode, path);
2022 if (err == 0) {
2023 ext_inode_hdr(inode)->eh_depth = 0;
2024 ext_inode_hdr(inode)->eh_max =
2025 cpu_to_le16(ext4_ext_space_root(inode));
2026 err = ext4_ext_dirty(handle, inode, path);
2027 }
2028 }
2029out:
2030 ext4_ext_tree_changed(inode);
2031 ext4_ext_drop_refs(path);
2032 kfree(path);
2033 ext4_journal_stop(handle);
2034
2035 return err;
2036}
2037
2038/*
2039 * called at mount time
2040 */
2041void ext4_ext_init(struct super_block *sb)
2042{
2043 /*
2044 * possible initialization would be here
2045 */
2046
2047 if (test_opt(sb, EXTENTS)) {
2048 printk("EXT4-fs: file extents enabled");
Robert P. J. Daybbf2f9f2007-02-17 19:20:16 +01002049#ifdef AGGRESSIVE_TEST
2050 printk(", aggressive tests");
Alex Tomasa86c6182006-10-11 01:21:03 -07002051#endif
2052#ifdef CHECK_BINSEARCH
2053 printk(", check binsearch");
2054#endif
2055#ifdef EXTENTS_STATS
2056 printk(", stats");
2057#endif
2058 printk("\n");
2059#ifdef EXTENTS_STATS
2060 spin_lock_init(&EXT4_SB(sb)->s_ext_stats_lock);
2061 EXT4_SB(sb)->s_ext_min = 1 << 30;
2062 EXT4_SB(sb)->s_ext_max = 0;
2063#endif
2064 }
2065}
2066
2067/*
2068 * called at umount time
2069 */
2070void ext4_ext_release(struct super_block *sb)
2071{
2072 if (!test_opt(sb, EXTENTS))
2073 return;
2074
2075#ifdef EXTENTS_STATS
2076 if (EXT4_SB(sb)->s_ext_blocks && EXT4_SB(sb)->s_ext_extents) {
2077 struct ext4_sb_info *sbi = EXT4_SB(sb);
2078 printk(KERN_ERR "EXT4-fs: %lu blocks in %lu extents (%lu ave)\n",
2079 sbi->s_ext_blocks, sbi->s_ext_extents,
2080 sbi->s_ext_blocks / sbi->s_ext_extents);
2081 printk(KERN_ERR "EXT4-fs: extents: %lu min, %lu max, max depth %lu\n",
2082 sbi->s_ext_min, sbi->s_ext_max, sbi->s_depth_max);
2083 }
2084#endif
2085}
2086
Amit Arora56055d32007-07-17 21:42:38 -04002087/*
2088 * This function is called by ext4_ext_get_blocks() if someone tries to write
2089 * to an uninitialized extent. It may result in splitting the uninitialized
2090 * extent into multiple extents (upto three - one initialized and two
2091 * uninitialized).
2092 * There are three possibilities:
2093 * a> There is no split required: Entire extent should be initialized
2094 * b> Splits in two extents: Write is happening at either end of the extent
2095 * c> Splits in three extents: Somone is writing in middle of the extent
2096 */
2097int ext4_ext_convert_to_initialized(handle_t *handle, struct inode *inode,
2098 struct ext4_ext_path *path,
2099 ext4_fsblk_t iblock,
2100 unsigned long max_blocks)
2101{
2102 struct ext4_extent *ex, newex;
2103 struct ext4_extent *ex1 = NULL;
2104 struct ext4_extent *ex2 = NULL;
2105 struct ext4_extent *ex3 = NULL;
2106 struct ext4_extent_header *eh;
2107 unsigned int allocated, ee_block, ee_len, depth;
2108 ext4_fsblk_t newblock;
2109 int err = 0;
2110 int ret = 0;
2111
2112 depth = ext_depth(inode);
2113 eh = path[depth].p_hdr;
2114 ex = path[depth].p_ext;
2115 ee_block = le32_to_cpu(ex->ee_block);
2116 ee_len = ext4_ext_get_actual_len(ex);
2117 allocated = ee_len - (iblock - ee_block);
2118 newblock = iblock - ee_block + ext_pblock(ex);
2119 ex2 = ex;
2120
2121 /* ex1: ee_block to iblock - 1 : uninitialized */
2122 if (iblock > ee_block) {
2123 ex1 = ex;
2124 ex1->ee_len = cpu_to_le16(iblock - ee_block);
2125 ext4_ext_mark_uninitialized(ex1);
2126 ex2 = &newex;
2127 }
2128 /*
2129 * for sanity, update the length of the ex2 extent before
2130 * we insert ex3, if ex1 is NULL. This is to avoid temporary
2131 * overlap of blocks.
2132 */
2133 if (!ex1 && allocated > max_blocks)
2134 ex2->ee_len = cpu_to_le16(max_blocks);
2135 /* ex3: to ee_block + ee_len : uninitialised */
2136 if (allocated > max_blocks) {
2137 unsigned int newdepth;
2138 ex3 = &newex;
2139 ex3->ee_block = cpu_to_le32(iblock + max_blocks);
2140 ext4_ext_store_pblock(ex3, newblock + max_blocks);
2141 ex3->ee_len = cpu_to_le16(allocated - max_blocks);
2142 ext4_ext_mark_uninitialized(ex3);
2143 err = ext4_ext_insert_extent(handle, inode, path, ex3);
2144 if (err)
2145 goto out;
2146 /*
2147 * The depth, and hence eh & ex might change
2148 * as part of the insert above.
2149 */
2150 newdepth = ext_depth(inode);
2151 if (newdepth != depth) {
2152 depth = newdepth;
2153 path = ext4_ext_find_extent(inode, iblock, NULL);
2154 if (IS_ERR(path)) {
2155 err = PTR_ERR(path);
2156 path = NULL;
2157 goto out;
2158 }
2159 eh = path[depth].p_hdr;
2160 ex = path[depth].p_ext;
2161 if (ex2 != &newex)
2162 ex2 = ex;
2163 }
2164 allocated = max_blocks;
2165 }
2166 /*
2167 * If there was a change of depth as part of the
2168 * insertion of ex3 above, we need to update the length
2169 * of the ex1 extent again here
2170 */
2171 if (ex1 && ex1 != ex) {
2172 ex1 = ex;
2173 ex1->ee_len = cpu_to_le16(iblock - ee_block);
2174 ext4_ext_mark_uninitialized(ex1);
2175 ex2 = &newex;
2176 }
2177 /* ex2: iblock to iblock + maxblocks-1 : initialised */
2178 ex2->ee_block = cpu_to_le32(iblock);
Amit Arora56055d32007-07-17 21:42:38 -04002179 ext4_ext_store_pblock(ex2, newblock);
2180 ex2->ee_len = cpu_to_le16(allocated);
2181 if (ex2 != ex)
2182 goto insert;
2183 err = ext4_ext_get_access(handle, inode, path + depth);
2184 if (err)
2185 goto out;
2186 /*
2187 * New (initialized) extent starts from the first block
2188 * in the current extent. i.e., ex2 == ex
2189 * We have to see if it can be merged with the extent
2190 * on the left.
2191 */
2192 if (ex2 > EXT_FIRST_EXTENT(eh)) {
2193 /*
2194 * To merge left, pass "ex2 - 1" to try_to_merge(),
2195 * since it merges towards right _only_.
2196 */
2197 ret = ext4_ext_try_to_merge(inode, path, ex2 - 1);
2198 if (ret) {
2199 err = ext4_ext_correct_indexes(handle, inode, path);
2200 if (err)
2201 goto out;
2202 depth = ext_depth(inode);
2203 ex2--;
2204 }
2205 }
2206 /*
2207 * Try to Merge towards right. This might be required
2208 * only when the whole extent is being written to.
2209 * i.e. ex2 == ex and ex3 == NULL.
2210 */
2211 if (!ex3) {
2212 ret = ext4_ext_try_to_merge(inode, path, ex2);
2213 if (ret) {
2214 err = ext4_ext_correct_indexes(handle, inode, path);
2215 if (err)
2216 goto out;
2217 }
2218 }
2219 /* Mark modified extent as dirty */
2220 err = ext4_ext_dirty(handle, inode, path + depth);
2221 goto out;
2222insert:
2223 err = ext4_ext_insert_extent(handle, inode, path, &newex);
2224out:
2225 return err ? err : allocated;
2226}
2227
Alex Tomasf65e6fb2006-10-11 01:21:05 -07002228int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
2229 ext4_fsblk_t iblock,
Alex Tomasa86c6182006-10-11 01:21:03 -07002230 unsigned long max_blocks, struct buffer_head *bh_result,
2231 int create, int extend_disksize)
2232{
2233 struct ext4_ext_path *path = NULL;
Amit Arora56055d32007-07-17 21:42:38 -04002234 struct ext4_extent_header *eh;
Alex Tomasa86c6182006-10-11 01:21:03 -07002235 struct ext4_extent newex, *ex;
Alex Tomasf65e6fb2006-10-11 01:21:05 -07002236 ext4_fsblk_t goal, newblock;
Amit Arora56055d32007-07-17 21:42:38 -04002237 int err = 0, depth, ret;
Alex Tomasa86c6182006-10-11 01:21:03 -07002238 unsigned long allocated = 0;
2239
2240 __clear_bit(BH_New, &bh_result->b_state);
2241 ext_debug("blocks %d/%lu requested for inode %u\n", (int) iblock,
2242 max_blocks, (unsigned) inode->i_ino);
2243 mutex_lock(&EXT4_I(inode)->truncate_mutex);
2244
2245 /* check in cache */
Avantika Mathur7e028972006-12-06 20:41:33 -08002246 goal = ext4_ext_in_cache(inode, iblock, &newex);
2247 if (goal) {
Alex Tomasa86c6182006-10-11 01:21:03 -07002248 if (goal == EXT4_EXT_CACHE_GAP) {
2249 if (!create) {
Amit Arora56055d32007-07-17 21:42:38 -04002250 /*
2251 * block isn't allocated yet and
2252 * user doesn't want to allocate it
2253 */
Alex Tomasa86c6182006-10-11 01:21:03 -07002254 goto out2;
2255 }
2256 /* we should allocate requested block */
2257 } else if (goal == EXT4_EXT_CACHE_EXTENT) {
2258 /* block is already allocated */
Dave Kleikamp8c55e202007-05-24 13:04:54 -04002259 newblock = iblock
2260 - le32_to_cpu(newex.ee_block)
2261 + ext_pblock(&newex);
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002262 /* number of remaining blocks in the extent */
Alex Tomasa86c6182006-10-11 01:21:03 -07002263 allocated = le16_to_cpu(newex.ee_len) -
2264 (iblock - le32_to_cpu(newex.ee_block));
2265 goto out;
2266 } else {
2267 BUG();
2268 }
2269 }
2270
2271 /* find extent for this block */
2272 path = ext4_ext_find_extent(inode, iblock, NULL);
2273 if (IS_ERR(path)) {
2274 err = PTR_ERR(path);
2275 path = NULL;
2276 goto out2;
2277 }
2278
2279 depth = ext_depth(inode);
2280
2281 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002282 * consistent leaf must not be empty;
2283 * this situation is possible, though, _during_ tree modification;
Alex Tomasa86c6182006-10-11 01:21:03 -07002284 * this is why assert can't be put in ext4_ext_find_extent()
2285 */
2286 BUG_ON(path[depth].p_ext == NULL && depth != 0);
Amit Arora56055d32007-07-17 21:42:38 -04002287 eh = path[depth].p_hdr;
Alex Tomasa86c6182006-10-11 01:21:03 -07002288
Avantika Mathur7e028972006-12-06 20:41:33 -08002289 ex = path[depth].p_ext;
2290 if (ex) {
Dave Kleikamp8c55e202007-05-24 13:04:54 -04002291 unsigned long ee_block = le32_to_cpu(ex->ee_block);
Alex Tomasf65e6fb2006-10-11 01:21:05 -07002292 ext4_fsblk_t ee_start = ext_pblock(ex);
Amit Aroraa2df2a62007-07-17 21:42:41 -04002293 unsigned short ee_len;
Suparna Bhattacharya471d4012006-10-11 01:21:06 -07002294
2295 /*
Suparna Bhattacharya471d4012006-10-11 01:21:06 -07002296 * Uninitialized extents are treated as holes, except that
Amit Arora56055d32007-07-17 21:42:38 -04002297 * we split out initialized portions during a write.
Suparna Bhattacharya471d4012006-10-11 01:21:06 -07002298 */
Amit Aroraa2df2a62007-07-17 21:42:41 -04002299 ee_len = ext4_ext_get_actual_len(ex);
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002300 /* if found extent covers block, simply return it */
Dave Kleikamp8c55e202007-05-24 13:04:54 -04002301 if (iblock >= ee_block && iblock < ee_block + ee_len) {
Alex Tomasa86c6182006-10-11 01:21:03 -07002302 newblock = iblock - ee_block + ee_start;
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002303 /* number of remaining blocks in the extent */
Alex Tomasa86c6182006-10-11 01:21:03 -07002304 allocated = ee_len - (iblock - ee_block);
Mingming Cao2ae02102006-10-11 01:21:11 -07002305 ext_debug("%d fit into %lu:%d -> %llu\n", (int) iblock,
Alex Tomasa86c6182006-10-11 01:21:03 -07002306 ee_block, ee_len, newblock);
Amit Arora56055d32007-07-17 21:42:38 -04002307
Amit Aroraa2df2a62007-07-17 21:42:41 -04002308 /* Do not put uninitialized extent in the cache */
Amit Arora56055d32007-07-17 21:42:38 -04002309 if (!ext4_ext_is_uninitialized(ex)) {
Amit Aroraa2df2a62007-07-17 21:42:41 -04002310 ext4_ext_put_in_cache(inode, ee_block,
2311 ee_len, ee_start,
2312 EXT4_EXT_CACHE_EXTENT);
Amit Arora56055d32007-07-17 21:42:38 -04002313 goto out;
2314 }
2315 if (create == EXT4_CREATE_UNINITIALIZED_EXT)
2316 goto out;
2317 if (!create)
2318 goto out2;
2319
2320 ret = ext4_ext_convert_to_initialized(handle, inode,
2321 path, iblock,
2322 max_blocks);
2323 if (ret <= 0)
2324 goto out2;
2325 else
2326 allocated = ret;
2327 goto outnew;
Alex Tomasa86c6182006-10-11 01:21:03 -07002328 }
2329 }
2330
2331 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002332 * requested block isn't allocated yet;
Alex Tomasa86c6182006-10-11 01:21:03 -07002333 * we couldn't try to create block if create flag is zero
2334 */
2335 if (!create) {
Amit Arora56055d32007-07-17 21:42:38 -04002336 /*
2337 * put just found gap into cache to speed up
2338 * subsequent requests
2339 */
Alex Tomasa86c6182006-10-11 01:21:03 -07002340 ext4_ext_put_gap_in_cache(inode, path, iblock);
2341 goto out2;
2342 }
2343 /*
Andrew Morton63f57932006-10-11 01:21:24 -07002344 * Okay, we need to do block allocation. Lazily initialize the block
2345 * allocation info here if necessary.
2346 */
Alex Tomasa86c6182006-10-11 01:21:03 -07002347 if (S_ISREG(inode->i_mode) && (!EXT4_I(inode)->i_block_alloc_info))
2348 ext4_init_block_alloc_info(inode);
2349
2350 /* allocate new block */
2351 goal = ext4_ext_find_goal(inode, path, iblock);
Amit Arora25d14f92007-05-24 13:04:13 -04002352
Amit Arora749269f2007-07-18 09:02:56 -04002353 /*
2354 * See if request is beyond maximum number of blocks we can have in
2355 * a single extent. For an initialized extent this limit is
2356 * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is
2357 * EXT_UNINIT_MAX_LEN.
2358 */
2359 if (max_blocks > EXT_INIT_MAX_LEN &&
2360 create != EXT4_CREATE_UNINITIALIZED_EXT)
2361 max_blocks = EXT_INIT_MAX_LEN;
2362 else if (max_blocks > EXT_UNINIT_MAX_LEN &&
2363 create == EXT4_CREATE_UNINITIALIZED_EXT)
2364 max_blocks = EXT_UNINIT_MAX_LEN;
2365
Amit Arora25d14f92007-05-24 13:04:13 -04002366 /* Check if we can really insert (iblock)::(iblock+max_blocks) extent */
2367 newex.ee_block = cpu_to_le32(iblock);
2368 newex.ee_len = cpu_to_le16(max_blocks);
2369 err = ext4_ext_check_overlap(inode, &newex, path);
2370 if (err)
2371 allocated = le16_to_cpu(newex.ee_len);
2372 else
2373 allocated = max_blocks;
Alex Tomasa86c6182006-10-11 01:21:03 -07002374 newblock = ext4_new_blocks(handle, inode, goal, &allocated, &err);
2375 if (!newblock)
2376 goto out2;
Mingming Cao2ae02102006-10-11 01:21:11 -07002377 ext_debug("allocate new block: goal %llu, found %llu/%lu\n",
Alex Tomasa86c6182006-10-11 01:21:03 -07002378 goal, newblock, allocated);
2379
2380 /* try to insert new extent into found leaf and return */
Alex Tomasf65e6fb2006-10-11 01:21:05 -07002381 ext4_ext_store_pblock(&newex, newblock);
Alex Tomasa86c6182006-10-11 01:21:03 -07002382 newex.ee_len = cpu_to_le16(allocated);
Amit Aroraa2df2a62007-07-17 21:42:41 -04002383 if (create == EXT4_CREATE_UNINITIALIZED_EXT) /* Mark uninitialized */
2384 ext4_ext_mark_uninitialized(&newex);
Alex Tomasa86c6182006-10-11 01:21:03 -07002385 err = ext4_ext_insert_extent(handle, inode, path, &newex);
Alex Tomas315054f2007-05-24 13:04:25 -04002386 if (err) {
2387 /* free data blocks we just allocated */
2388 ext4_free_blocks(handle, inode, ext_pblock(&newex),
2389 le16_to_cpu(newex.ee_len));
Alex Tomasa86c6182006-10-11 01:21:03 -07002390 goto out2;
Alex Tomas315054f2007-05-24 13:04:25 -04002391 }
Alex Tomasa86c6182006-10-11 01:21:03 -07002392
2393 if (extend_disksize && inode->i_size > EXT4_I(inode)->i_disksize)
2394 EXT4_I(inode)->i_disksize = inode->i_size;
2395
2396 /* previous routine could use block we allocated */
Alex Tomasf65e6fb2006-10-11 01:21:05 -07002397 newblock = ext_pblock(&newex);
Amit Arora56055d32007-07-17 21:42:38 -04002398outnew:
Alex Tomasa86c6182006-10-11 01:21:03 -07002399 __set_bit(BH_New, &bh_result->b_state);
2400
Amit Aroraa2df2a62007-07-17 21:42:41 -04002401 /* Cache only when it is _not_ an uninitialized extent */
2402 if (create != EXT4_CREATE_UNINITIALIZED_EXT)
2403 ext4_ext_put_in_cache(inode, iblock, allocated, newblock,
2404 EXT4_EXT_CACHE_EXTENT);
Alex Tomasa86c6182006-10-11 01:21:03 -07002405out:
2406 if (allocated > max_blocks)
2407 allocated = max_blocks;
2408 ext4_ext_show_leaf(inode, path);
2409 __set_bit(BH_Mapped, &bh_result->b_state);
2410 bh_result->b_bdev = inode->i_sb->s_bdev;
2411 bh_result->b_blocknr = newblock;
2412out2:
2413 if (path) {
2414 ext4_ext_drop_refs(path);
2415 kfree(path);
2416 }
2417 mutex_unlock(&EXT4_I(inode)->truncate_mutex);
2418
2419 return err ? err : allocated;
2420}
2421
2422void ext4_ext_truncate(struct inode * inode, struct page *page)
2423{
2424 struct address_space *mapping = inode->i_mapping;
2425 struct super_block *sb = inode->i_sb;
2426 unsigned long last_block;
2427 handle_t *handle;
2428 int err = 0;
2429
2430 /*
2431 * probably first extent we're gonna free will be last in block
2432 */
2433 err = ext4_writepage_trans_blocks(inode) + 3;
2434 handle = ext4_journal_start(inode, err);
2435 if (IS_ERR(handle)) {
2436 if (page) {
2437 clear_highpage(page);
2438 flush_dcache_page(page);
2439 unlock_page(page);
2440 page_cache_release(page);
2441 }
2442 return;
2443 }
2444
2445 if (page)
2446 ext4_block_truncate_page(handle, page, mapping, inode->i_size);
2447
2448 mutex_lock(&EXT4_I(inode)->truncate_mutex);
2449 ext4_ext_invalidate_cache(inode);
2450
2451 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002452 * TODO: optimization is possible here.
2453 * Probably we need not scan at all,
2454 * because page truncation is enough.
Alex Tomasa86c6182006-10-11 01:21:03 -07002455 */
2456 if (ext4_orphan_add(handle, inode))
2457 goto out_stop;
2458
2459 /* we have to know where to truncate from in crash case */
2460 EXT4_I(inode)->i_disksize = inode->i_size;
2461 ext4_mark_inode_dirty(handle, inode);
2462
2463 last_block = (inode->i_size + sb->s_blocksize - 1)
2464 >> EXT4_BLOCK_SIZE_BITS(sb);
2465 err = ext4_ext_remove_space(inode, last_block);
2466
2467 /* In a multi-transaction truncate, we only make the final
Amit Arora56055d32007-07-17 21:42:38 -04002468 * transaction synchronous.
2469 */
Alex Tomasa86c6182006-10-11 01:21:03 -07002470 if (IS_SYNC(inode))
2471 handle->h_sync = 1;
2472
2473out_stop:
2474 /*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002475 * If this was a simple ftruncate() and the file will remain alive,
Alex Tomasa86c6182006-10-11 01:21:03 -07002476 * then we need to clear up the orphan record which we created above.
2477 * However, if this was a real unlink then we were called by
2478 * ext4_delete_inode(), and we allow that function to clean up the
2479 * orphan info for us.
2480 */
2481 if (inode->i_nlink)
2482 ext4_orphan_del(handle, inode);
2483
2484 mutex_unlock(&EXT4_I(inode)->truncate_mutex);
2485 ext4_journal_stop(handle);
2486}
2487
2488/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002489 * ext4_ext_writepage_trans_blocks:
2490 * calculate max number of blocks we could modify
Alex Tomasa86c6182006-10-11 01:21:03 -07002491 * in order to allocate new block for an inode
2492 */
2493int ext4_ext_writepage_trans_blocks(struct inode *inode, int num)
2494{
2495 int needed;
2496
2497 needed = ext4_ext_calc_credits_for_insert(inode, NULL);
2498
Randy Dunlapd0d856e2006-10-11 01:21:07 -07002499 /* caller wants to allocate num blocks, but note it includes sb */
Alex Tomasa86c6182006-10-11 01:21:03 -07002500 needed = needed * num - (num - 1);
2501
2502#ifdef CONFIG_QUOTA
2503 needed += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
2504#endif
2505
2506 return needed;
2507}
Amit Aroraa2df2a62007-07-17 21:42:41 -04002508
2509/*
2510 * preallocate space for a file. This implements ext4's fallocate inode
2511 * operation, which gets called from sys_fallocate system call.
2512 * For block-mapped files, posix_fallocate should fall back to the method
2513 * of writing zeroes to the required new blocks (the same behavior which is
2514 * expected for file systems which do not support fallocate() system call).
2515 */
2516long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len)
2517{
2518 handle_t *handle;
2519 ext4_fsblk_t block, max_blocks;
2520 ext4_fsblk_t nblocks = 0;
2521 int ret = 0;
2522 int ret2 = 0;
2523 int retries = 0;
2524 struct buffer_head map_bh;
2525 unsigned int credits, blkbits = inode->i_blkbits;
2526
2527 /*
2528 * currently supporting (pre)allocate mode for extent-based
2529 * files _only_
2530 */
2531 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
2532 return -EOPNOTSUPP;
2533
2534 /* preallocation to directories is currently not supported */
2535 if (S_ISDIR(inode->i_mode))
2536 return -ENODEV;
2537
2538 block = offset >> blkbits;
2539 max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
2540 - block;
2541
2542 /*
2543 * credits to insert 1 extent into extent tree + buffers to be able to
2544 * modify 1 super block, 1 block bitmap and 1 group descriptor.
2545 */
2546 credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + 3;
2547retry:
2548 while (ret >= 0 && ret < max_blocks) {
2549 block = block + ret;
2550 max_blocks = max_blocks - ret;
2551 handle = ext4_journal_start(inode, credits);
2552 if (IS_ERR(handle)) {
2553 ret = PTR_ERR(handle);
2554 break;
2555 }
2556
2557 ret = ext4_ext_get_blocks(handle, inode, block,
2558 max_blocks, &map_bh,
2559 EXT4_CREATE_UNINITIALIZED_EXT, 0);
2560 WARN_ON(!ret);
2561 if (!ret) {
2562 ext4_error(inode->i_sb, "ext4_fallocate",
2563 "ext4_ext_get_blocks returned 0! inode#%lu"
2564 ", block=%llu, max_blocks=%llu",
2565 inode->i_ino, block, max_blocks);
2566 ret = -EIO;
2567 ext4_mark_inode_dirty(handle, inode);
2568 ret2 = ext4_journal_stop(handle);
2569 break;
2570 }
2571 if (ret > 0) {
2572 /* check wrap through sign-bit/zero here */
2573 if ((block + ret) < 0 || (block + ret) < block) {
2574 ret = -EIO;
2575 ext4_mark_inode_dirty(handle, inode);
2576 ret2 = ext4_journal_stop(handle);
2577 break;
2578 }
2579 if (buffer_new(&map_bh) && ((block + ret) >
2580 (EXT4_BLOCK_ALIGN(i_size_read(inode), blkbits)
2581 >> blkbits)))
2582 nblocks = nblocks + ret;
2583 }
2584
2585 /* Update ctime if new blocks get allocated */
2586 if (nblocks) {
2587 struct timespec now;
2588
2589 now = current_fs_time(inode->i_sb);
2590 if (!timespec_equal(&inode->i_ctime, &now))
2591 inode->i_ctime = now;
2592 }
2593
2594 ext4_mark_inode_dirty(handle, inode);
2595 ret2 = ext4_journal_stop(handle);
2596 if (ret2)
2597 break;
2598 }
2599
2600 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
2601 goto retry;
2602
2603 /*
2604 * Time to update the file size.
2605 * Update only when preallocation was requested beyond the file size.
2606 */
2607 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
2608 (offset + len) > i_size_read(inode)) {
2609 if (ret > 0) {
2610 /*
2611 * if no error, we assume preallocation succeeded
2612 * completely
2613 */
2614 mutex_lock(&inode->i_mutex);
2615 i_size_write(inode, offset + len);
2616 EXT4_I(inode)->i_disksize = i_size_read(inode);
2617 mutex_unlock(&inode->i_mutex);
2618 } else if (ret < 0 && nblocks) {
2619 /* Handle partial allocation scenario */
2620 loff_t newsize;
2621
2622 mutex_lock(&inode->i_mutex);
2623 newsize = (nblocks << blkbits) + i_size_read(inode);
2624 i_size_write(inode, EXT4_BLOCK_ALIGN(newsize, blkbits));
2625 EXT4_I(inode)->i_disksize = i_size_read(inode);
2626 mutex_unlock(&inode->i_mutex);
2627 }
2628 }
2629
2630 return ret > 0 ? ret2 : ret;
2631}