Merge branch 'topic/intel8x0' into for-linus
[linux-2.6] / fs / ext4 / ialloc.c
1 /*
2  *  linux/fs/ext4/ialloc.c
3  *
4  * Copyright (C) 1992, 1993, 1994, 1995
5  * Remy Card (card@masi.ibp.fr)
6  * Laboratoire MASI - Institut Blaise Pascal
7  * Universite Pierre et Marie Curie (Paris VI)
8  *
9  *  BSD ufs-inspired inode and directory allocation by
10  *  Stephen Tweedie (sct@redhat.com), 1993
11  *  Big-endian to little-endian byte-swapping/bitmaps by
12  *        David S. Miller (davem@caip.rutgers.edu), 1995
13  */
14
15 #include <linux/time.h>
16 #include <linux/fs.h>
17 #include <linux/jbd2.h>
18 #include <linux/stat.h>
19 #include <linux/string.h>
20 #include <linux/quotaops.h>
21 #include <linux/buffer_head.h>
22 #include <linux/random.h>
23 #include <linux/bitops.h>
24 #include <linux/blkdev.h>
25 #include <asm/byteorder.h>
26 #include "ext4.h"
27 #include "ext4_jbd2.h"
28 #include "xattr.h"
29 #include "acl.h"
30 #include "group.h"
31
32 /*
33  * ialloc.c contains the inodes allocation and deallocation routines
34  */
35
36 /*
37  * The free inodes are managed by bitmaps.  A file system contains several
38  * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
39  * block for inodes, N blocks for the inode table and data blocks.
40  *
41  * The file system contains group descriptors which are located after the
42  * super block.  Each descriptor contains the number of the bitmap block and
43  * the free blocks count in the block.
44  */
45
46 /*
47  * To avoid calling the atomic setbit hundreds or thousands of times, we only
48  * need to use it within a single byte (to ensure we get endianness right).
49  * We can use memset for the rest of the bitmap as there are no other users.
50  */
51 void mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
52 {
53         int i;
54
55         if (start_bit >= end_bit)
56                 return;
57
58         ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
59         for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
60                 ext4_set_bit(i, bitmap);
61         if (i < end_bit)
62                 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
63 }
64
65 /* Initializes an uninitialized inode bitmap */
66 unsigned ext4_init_inode_bitmap(struct super_block *sb, struct buffer_head *bh,
67                                 ext4_group_t block_group,
68                                 struct ext4_group_desc *gdp)
69 {
70         struct ext4_sb_info *sbi = EXT4_SB(sb);
71
72         J_ASSERT_BH(bh, buffer_locked(bh));
73
74         /* If checksum is bad mark all blocks and inodes use to prevent
75          * allocation, essentially implementing a per-group read-only flag. */
76         if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) {
77                 ext4_error(sb, __func__, "Checksum bad for group %u",
78                            block_group);
79                 ext4_free_blks_set(sb, gdp, 0);
80                 ext4_free_inodes_set(sb, gdp, 0);
81                 ext4_itable_unused_set(sb, gdp, 0);
82                 memset(bh->b_data, 0xff, sb->s_blocksize);
83                 return 0;
84         }
85
86         memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
87         mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8,
88                         bh->b_data);
89
90         return EXT4_INODES_PER_GROUP(sb);
91 }
92
93 /*
94  * Read the inode allocation bitmap for a given block_group, reading
95  * into the specified slot in the superblock's bitmap cache.
96  *
97  * Return buffer_head of bitmap on success or NULL.
98  */
99 static struct buffer_head *
100 ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
101 {
102         struct ext4_group_desc *desc;
103         struct buffer_head *bh = NULL;
104         ext4_fsblk_t bitmap_blk;
105
106         desc = ext4_get_group_desc(sb, block_group, NULL);
107         if (!desc)
108                 return NULL;
109         bitmap_blk = ext4_inode_bitmap(sb, desc);
110         bh = sb_getblk(sb, bitmap_blk);
111         if (unlikely(!bh)) {
112                 ext4_error(sb, __func__,
113                             "Cannot read inode bitmap - "
114                             "block_group = %u, inode_bitmap = %llu",
115                             block_group, bitmap_blk);
116                 return NULL;
117         }
118         if (bitmap_uptodate(bh))
119                 return bh;
120
121         lock_buffer(bh);
122         if (bitmap_uptodate(bh)) {
123                 unlock_buffer(bh);
124                 return bh;
125         }
126         spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));
127         if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
128                 ext4_init_inode_bitmap(sb, bh, block_group, desc);
129                 set_bitmap_uptodate(bh);
130                 set_buffer_uptodate(bh);
131                 spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
132                 unlock_buffer(bh);
133                 return bh;
134         }
135         spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
136         if (buffer_uptodate(bh)) {
137                 /*
138                  * if not uninit if bh is uptodate,
139                  * bitmap is also uptodate
140                  */
141                 set_bitmap_uptodate(bh);
142                 unlock_buffer(bh);
143                 return bh;
144         }
145         /*
146          * submit the buffer_head for read. We can
147          * safely mark the bitmap as uptodate now.
148          * We do it here so the bitmap uptodate bit
149          * get set with buffer lock held.
150          */
151         set_bitmap_uptodate(bh);
152         if (bh_submit_read(bh) < 0) {
153                 put_bh(bh);
154                 ext4_error(sb, __func__,
155                             "Cannot read inode bitmap - "
156                             "block_group = %u, inode_bitmap = %llu",
157                             block_group, bitmap_blk);
158                 return NULL;
159         }
160         return bh;
161 }
162
163 /*
164  * NOTE! When we get the inode, we're the only people
165  * that have access to it, and as such there are no
166  * race conditions we have to worry about. The inode
167  * is not on the hash-lists, and it cannot be reached
168  * through the filesystem because the directory entry
169  * has been deleted earlier.
170  *
171  * HOWEVER: we must make sure that we get no aliases,
172  * which means that we have to call "clear_inode()"
173  * _before_ we mark the inode not in use in the inode
174  * bitmaps. Otherwise a newly created file might use
175  * the same inode number (not actually the same pointer
176  * though), and then we'd have two inodes sharing the
177  * same inode number and space on the harddisk.
178  */
179 void ext4_free_inode(handle_t *handle, struct inode *inode)
180 {
181         struct super_block *sb = inode->i_sb;
182         int is_directory;
183         unsigned long ino;
184         struct buffer_head *bitmap_bh = NULL;
185         struct buffer_head *bh2;
186         ext4_group_t block_group;
187         unsigned long bit;
188         struct ext4_group_desc *gdp;
189         struct ext4_super_block *es;
190         struct ext4_sb_info *sbi;
191         int fatal = 0, err, count, cleared;
192         ext4_group_t flex_group;
193
194         if (atomic_read(&inode->i_count) > 1) {
195                 printk(KERN_ERR "ext4_free_inode: inode has count=%d\n",
196                        atomic_read(&inode->i_count));
197                 return;
198         }
199         if (inode->i_nlink) {
200                 printk(KERN_ERR "ext4_free_inode: inode has nlink=%d\n",
201                        inode->i_nlink);
202                 return;
203         }
204         if (!sb) {
205                 printk(KERN_ERR "ext4_free_inode: inode on "
206                        "nonexistent device\n");
207                 return;
208         }
209         sbi = EXT4_SB(sb);
210
211         ino = inode->i_ino;
212         ext4_debug("freeing inode %lu\n", ino);
213         trace_mark(ext4_free_inode,
214                    "dev %s ino %lu mode %d uid %lu gid %lu bocks %llu",
215                    sb->s_id, inode->i_ino, inode->i_mode,
216                    (unsigned long) inode->i_uid, (unsigned long) inode->i_gid,
217                    (unsigned long long) inode->i_blocks);
218
219         /*
220          * Note: we must free any quota before locking the superblock,
221          * as writing the quota to disk may need the lock as well.
222          */
223         DQUOT_INIT(inode);
224         ext4_xattr_delete_inode(handle, inode);
225         DQUOT_FREE_INODE(inode);
226         DQUOT_DROP(inode);
227
228         is_directory = S_ISDIR(inode->i_mode);
229
230         /* Do this BEFORE marking the inode not in use or returning an error */
231         clear_inode(inode);
232
233         es = EXT4_SB(sb)->s_es;
234         if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
235                 ext4_error(sb, "ext4_free_inode",
236                            "reserved or nonexistent inode %lu", ino);
237                 goto error_return;
238         }
239         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
240         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
241         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
242         if (!bitmap_bh)
243                 goto error_return;
244
245         BUFFER_TRACE(bitmap_bh, "get_write_access");
246         fatal = ext4_journal_get_write_access(handle, bitmap_bh);
247         if (fatal)
248                 goto error_return;
249
250         /* Ok, now we can actually update the inode bitmaps.. */
251         spin_lock(sb_bgl_lock(sbi, block_group));
252         cleared = ext4_clear_bit(bit, bitmap_bh->b_data);
253         spin_unlock(sb_bgl_lock(sbi, block_group));
254         if (!cleared)
255                 ext4_error(sb, "ext4_free_inode",
256                            "bit already cleared for inode %lu", ino);
257         else {
258                 gdp = ext4_get_group_desc(sb, block_group, &bh2);
259
260                 BUFFER_TRACE(bh2, "get_write_access");
261                 fatal = ext4_journal_get_write_access(handle, bh2);
262                 if (fatal) goto error_return;
263
264                 if (gdp) {
265                         spin_lock(sb_bgl_lock(sbi, block_group));
266                         count = ext4_free_inodes_count(sb, gdp) + 1;
267                         ext4_free_inodes_set(sb, gdp, count);
268                         if (is_directory) {
269                                 count = ext4_used_dirs_count(sb, gdp) - 1;
270                                 ext4_used_dirs_set(sb, gdp, count);
271                         }
272                         gdp->bg_checksum = ext4_group_desc_csum(sbi,
273                                                         block_group, gdp);
274                         spin_unlock(sb_bgl_lock(sbi, block_group));
275                         percpu_counter_inc(&sbi->s_freeinodes_counter);
276                         if (is_directory)
277                                 percpu_counter_dec(&sbi->s_dirs_counter);
278
279                         if (sbi->s_log_groups_per_flex) {
280                                 flex_group = ext4_flex_group(sbi, block_group);
281                                 spin_lock(sb_bgl_lock(sbi, flex_group));
282                                 sbi->s_flex_groups[flex_group].free_inodes++;
283                                 spin_unlock(sb_bgl_lock(sbi, flex_group));
284                         }
285                 }
286                 BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
287                 err = ext4_handle_dirty_metadata(handle, NULL, bh2);
288                 if (!fatal) fatal = err;
289         }
290         BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
291         err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
292         if (!fatal)
293                 fatal = err;
294         sb->s_dirt = 1;
295 error_return:
296         brelse(bitmap_bh);
297         ext4_std_error(sb, fatal);
298 }
299
300 /*
301  * There are two policies for allocating an inode.  If the new inode is
302  * a directory, then a forward search is made for a block group with both
303  * free space and a low directory-to-inode ratio; if that fails, then of
304  * the groups with above-average free space, that group with the fewest
305  * directories already is chosen.
306  *
307  * For other inodes, search forward from the parent directory\'s block
308  * group to find a free inode.
309  */
310 static int find_group_dir(struct super_block *sb, struct inode *parent,
311                                 ext4_group_t *best_group)
312 {
313         ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
314         unsigned int freei, avefreei;
315         struct ext4_group_desc *desc, *best_desc = NULL;
316         ext4_group_t group;
317         int ret = -1;
318
319         freei = percpu_counter_read_positive(&EXT4_SB(sb)->s_freeinodes_counter);
320         avefreei = freei / ngroups;
321
322         for (group = 0; group < ngroups; group++) {
323                 desc = ext4_get_group_desc(sb, group, NULL);
324                 if (!desc || !ext4_free_inodes_count(sb, desc))
325                         continue;
326                 if (ext4_free_inodes_count(sb, desc) < avefreei)
327                         continue;
328                 if (!best_desc ||
329                     (ext4_free_blks_count(sb, desc) >
330                      ext4_free_blks_count(sb, best_desc))) {
331                         *best_group = group;
332                         best_desc = desc;
333                         ret = 0;
334                 }
335         }
336         return ret;
337 }
338
339 #define free_block_ratio 10
340
341 static int find_group_flex(struct super_block *sb, struct inode *parent,
342                            ext4_group_t *best_group)
343 {
344         struct ext4_sb_info *sbi = EXT4_SB(sb);
345         struct ext4_group_desc *desc;
346         struct buffer_head *bh;
347         struct flex_groups *flex_group = sbi->s_flex_groups;
348         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
349         ext4_group_t parent_fbg_group = ext4_flex_group(sbi, parent_group);
350         ext4_group_t ngroups = sbi->s_groups_count;
351         int flex_size = ext4_flex_bg_size(sbi);
352         ext4_group_t best_flex = parent_fbg_group;
353         int blocks_per_flex = sbi->s_blocks_per_group * flex_size;
354         int flexbg_free_blocks;
355         int flex_freeb_ratio;
356         ext4_group_t n_fbg_groups;
357         ext4_group_t i;
358
359         n_fbg_groups = (sbi->s_groups_count + flex_size - 1) >>
360                 sbi->s_log_groups_per_flex;
361
362 find_close_to_parent:
363         flexbg_free_blocks = flex_group[best_flex].free_blocks;
364         flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
365         if (flex_group[best_flex].free_inodes &&
366             flex_freeb_ratio > free_block_ratio)
367                 goto found_flexbg;
368
369         if (best_flex && best_flex == parent_fbg_group) {
370                 best_flex--;
371                 goto find_close_to_parent;
372         }
373
374         for (i = 0; i < n_fbg_groups; i++) {
375                 if (i == parent_fbg_group || i == parent_fbg_group - 1)
376                         continue;
377
378                 flexbg_free_blocks = flex_group[i].free_blocks;
379                 flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
380
381                 if (flex_freeb_ratio > free_block_ratio &&
382                     flex_group[i].free_inodes) {
383                         best_flex = i;
384                         goto found_flexbg;
385                 }
386
387                 if (flex_group[best_flex].free_inodes == 0 ||
388                     (flex_group[i].free_blocks >
389                      flex_group[best_flex].free_blocks &&
390                      flex_group[i].free_inodes))
391                         best_flex = i;
392         }
393
394         if (!flex_group[best_flex].free_inodes ||
395             !flex_group[best_flex].free_blocks)
396                 return -1;
397
398 found_flexbg:
399         for (i = best_flex * flex_size; i < ngroups &&
400                      i < (best_flex + 1) * flex_size; i++) {
401                 desc = ext4_get_group_desc(sb, i, &bh);
402                 if (ext4_free_inodes_count(sb, desc)) {
403                         *best_group = i;
404                         goto out;
405                 }
406         }
407
408         return -1;
409 out:
410         return 0;
411 }
412
413 /*
414  * Orlov's allocator for directories.
415  *
416  * We always try to spread first-level directories.
417  *
418  * If there are blockgroups with both free inodes and free blocks counts
419  * not worse than average we return one with smallest directory count.
420  * Otherwise we simply return a random group.
421  *
422  * For the rest rules look so:
423  *
424  * It's OK to put directory into a group unless
425  * it has too many directories already (max_dirs) or
426  * it has too few free inodes left (min_inodes) or
427  * it has too few free blocks left (min_blocks) or
428  * it's already running too large debt (max_debt).
429  * Parent's group is preferred, if it doesn't satisfy these
430  * conditions we search cyclically through the rest. If none
431  * of the groups look good we just look for a group with more
432  * free inodes than average (starting at parent's group).
433  *
434  * Debt is incremented each time we allocate a directory and decremented
435  * when we allocate an inode, within 0--255.
436  */
437
438 #define INODE_COST 64
439 #define BLOCK_COST 256
440
441 static int find_group_orlov(struct super_block *sb, struct inode *parent,
442                                 ext4_group_t *group)
443 {
444         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
445         struct ext4_sb_info *sbi = EXT4_SB(sb);
446         struct ext4_super_block *es = sbi->s_es;
447         ext4_group_t ngroups = sbi->s_groups_count;
448         int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
449         unsigned int freei, avefreei;
450         ext4_fsblk_t freeb, avefreeb;
451         ext4_fsblk_t blocks_per_dir;
452         unsigned int ndirs;
453         int max_debt, max_dirs, min_inodes;
454         ext4_grpblk_t min_blocks;
455         ext4_group_t i;
456         struct ext4_group_desc *desc;
457
458         freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
459         avefreei = freei / ngroups;
460         freeb = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
461         avefreeb = freeb;
462         do_div(avefreeb, ngroups);
463         ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
464
465         if ((parent == sb->s_root->d_inode) ||
466             (EXT4_I(parent)->i_flags & EXT4_TOPDIR_FL)) {
467                 int best_ndir = inodes_per_group;
468                 ext4_group_t grp;
469                 int ret = -1;
470
471                 get_random_bytes(&grp, sizeof(grp));
472                 parent_group = (unsigned)grp % ngroups;
473                 for (i = 0; i < ngroups; i++) {
474                         grp = (parent_group + i) % ngroups;
475                         desc = ext4_get_group_desc(sb, grp, NULL);
476                         if (!desc || !ext4_free_inodes_count(sb, desc))
477                                 continue;
478                         if (ext4_used_dirs_count(sb, desc) >= best_ndir)
479                                 continue;
480                         if (ext4_free_inodes_count(sb, desc) < avefreei)
481                                 continue;
482                         if (ext4_free_blks_count(sb, desc) < avefreeb)
483                                 continue;
484                         *group = grp;
485                         ret = 0;
486                         best_ndir = ext4_used_dirs_count(sb, desc);
487                 }
488                 if (ret == 0)
489                         return ret;
490                 goto fallback;
491         }
492
493         blocks_per_dir = ext4_blocks_count(es) - freeb;
494         do_div(blocks_per_dir, ndirs);
495
496         max_dirs = ndirs / ngroups + inodes_per_group / 16;
497         min_inodes = avefreei - inodes_per_group / 4;
498         min_blocks = avefreeb - EXT4_BLOCKS_PER_GROUP(sb) / 4;
499
500         max_debt = EXT4_BLOCKS_PER_GROUP(sb);
501         max_debt /= max_t(int, blocks_per_dir, BLOCK_COST);
502         if (max_debt * INODE_COST > inodes_per_group)
503                 max_debt = inodes_per_group / INODE_COST;
504         if (max_debt > 255)
505                 max_debt = 255;
506         if (max_debt == 0)
507                 max_debt = 1;
508
509         for (i = 0; i < ngroups; i++) {
510                 *group = (parent_group + i) % ngroups;
511                 desc = ext4_get_group_desc(sb, *group, NULL);
512                 if (!desc || !ext4_free_inodes_count(sb, desc))
513                         continue;
514                 if (ext4_used_dirs_count(sb, desc) >= max_dirs)
515                         continue;
516                 if (ext4_free_inodes_count(sb, desc) < min_inodes)
517                         continue;
518                 if (ext4_free_blks_count(sb, desc) < min_blocks)
519                         continue;
520                 return 0;
521         }
522
523 fallback:
524         for (i = 0; i < ngroups; i++) {
525                 *group = (parent_group + i) % ngroups;
526                 desc = ext4_get_group_desc(sb, *group, NULL);
527                 if (desc && ext4_free_inodes_count(sb, desc) &&
528                         ext4_free_inodes_count(sb, desc) >= avefreei)
529                         return 0;
530         }
531
532         if (avefreei) {
533                 /*
534                  * The free-inodes counter is approximate, and for really small
535                  * filesystems the above test can fail to find any blockgroups
536                  */
537                 avefreei = 0;
538                 goto fallback;
539         }
540
541         return -1;
542 }
543
544 static int find_group_other(struct super_block *sb, struct inode *parent,
545                                 ext4_group_t *group)
546 {
547         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
548         ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
549         struct ext4_group_desc *desc;
550         ext4_group_t i;
551
552         /*
553          * Try to place the inode in its parent directory
554          */
555         *group = parent_group;
556         desc = ext4_get_group_desc(sb, *group, NULL);
557         if (desc && ext4_free_inodes_count(sb, desc) &&
558                         ext4_free_blks_count(sb, desc))
559                 return 0;
560
561         /*
562          * We're going to place this inode in a different blockgroup from its
563          * parent.  We want to cause files in a common directory to all land in
564          * the same blockgroup.  But we want files which are in a different
565          * directory which shares a blockgroup with our parent to land in a
566          * different blockgroup.
567          *
568          * So add our directory's i_ino into the starting point for the hash.
569          */
570         *group = (*group + parent->i_ino) % ngroups;
571
572         /*
573          * Use a quadratic hash to find a group with a free inode and some free
574          * blocks.
575          */
576         for (i = 1; i < ngroups; i <<= 1) {
577                 *group += i;
578                 if (*group >= ngroups)
579                         *group -= ngroups;
580                 desc = ext4_get_group_desc(sb, *group, NULL);
581                 if (desc && ext4_free_inodes_count(sb, desc) &&
582                                 ext4_free_blks_count(sb, desc))
583                         return 0;
584         }
585
586         /*
587          * That failed: try linear search for a free inode, even if that group
588          * has no free blocks.
589          */
590         *group = parent_group;
591         for (i = 0; i < ngroups; i++) {
592                 if (++*group >= ngroups)
593                         *group = 0;
594                 desc = ext4_get_group_desc(sb, *group, NULL);
595                 if (desc && ext4_free_inodes_count(sb, desc))
596                         return 0;
597         }
598
599         return -1;
600 }
601
602 /*
603  * claim the inode from the inode bitmap. If the group
604  * is uninit we need to take the groups's sb_bgl_lock
605  * and clear the uninit flag. The inode bitmap update
606  * and group desc uninit flag clear should be done
607  * after holding sb_bgl_lock so that ext4_read_inode_bitmap
608  * doesn't race with the ext4_claim_inode
609  */
610 static int ext4_claim_inode(struct super_block *sb,
611                         struct buffer_head *inode_bitmap_bh,
612                         unsigned long ino, ext4_group_t group, int mode)
613 {
614         int free = 0, retval = 0, count;
615         struct ext4_sb_info *sbi = EXT4_SB(sb);
616         struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group, NULL);
617
618         spin_lock(sb_bgl_lock(sbi, group));
619         if (ext4_set_bit(ino, inode_bitmap_bh->b_data)) {
620                 /* not a free inode */
621                 retval = 1;
622                 goto err_ret;
623         }
624         ino++;
625         if ((group == 0 && ino < EXT4_FIRST_INO(sb)) ||
626                         ino > EXT4_INODES_PER_GROUP(sb)) {
627                 spin_unlock(sb_bgl_lock(sbi, group));
628                 ext4_error(sb, __func__,
629                            "reserved inode or inode > inodes count - "
630                            "block_group = %u, inode=%lu", group,
631                            ino + group * EXT4_INODES_PER_GROUP(sb));
632                 return 1;
633         }
634         /* If we didn't allocate from within the initialized part of the inode
635          * table then we need to initialize up to this inode. */
636         if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
637
638                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
639                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
640                         /* When marking the block group with
641                          * ~EXT4_BG_INODE_UNINIT we don't want to depend
642                          * on the value of bg_itable_unused even though
643                          * mke2fs could have initialized the same for us.
644                          * Instead we calculated the value below
645                          */
646
647                         free = 0;
648                 } else {
649                         free = EXT4_INODES_PER_GROUP(sb) -
650                                 ext4_itable_unused_count(sb, gdp);
651                 }
652
653                 /*
654                  * Check the relative inode number against the last used
655                  * relative inode number in this group. if it is greater
656                  * we need to  update the bg_itable_unused count
657                  *
658                  */
659                 if (ino > free)
660                         ext4_itable_unused_set(sb, gdp,
661                                         (EXT4_INODES_PER_GROUP(sb) - ino));
662         }
663         count = ext4_free_inodes_count(sb, gdp) - 1;
664         ext4_free_inodes_set(sb, gdp, count);
665         if (S_ISDIR(mode)) {
666                 count = ext4_used_dirs_count(sb, gdp) + 1;
667                 ext4_used_dirs_set(sb, gdp, count);
668         }
669         gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
670 err_ret:
671         spin_unlock(sb_bgl_lock(sbi, group));
672         return retval;
673 }
674
675 /*
676  * There are two policies for allocating an inode.  If the new inode is
677  * a directory, then a forward search is made for a block group with both
678  * free space and a low directory-to-inode ratio; if that fails, then of
679  * the groups with above-average free space, that group with the fewest
680  * directories already is chosen.
681  *
682  * For other inodes, search forward from the parent directory's block
683  * group to find a free inode.
684  */
685 struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode)
686 {
687         struct super_block *sb;
688         struct buffer_head *inode_bitmap_bh = NULL;
689         struct buffer_head *group_desc_bh;
690         ext4_group_t group = 0;
691         unsigned long ino = 0;
692         struct inode *inode;
693         struct ext4_group_desc *gdp = NULL;
694         struct ext4_super_block *es;
695         struct ext4_inode_info *ei;
696         struct ext4_sb_info *sbi;
697         int ret2, err = 0;
698         struct inode *ret;
699         ext4_group_t i;
700         int free = 0;
701         static int once = 1;
702         ext4_group_t flex_group;
703
704         /* Cannot create files in a deleted directory */
705         if (!dir || !dir->i_nlink)
706                 return ERR_PTR(-EPERM);
707
708         sb = dir->i_sb;
709         trace_mark(ext4_request_inode, "dev %s dir %lu mode %d", sb->s_id,
710                    dir->i_ino, mode);
711         inode = new_inode(sb);
712         if (!inode)
713                 return ERR_PTR(-ENOMEM);
714         ei = EXT4_I(inode);
715
716         sbi = EXT4_SB(sb);
717         es = sbi->s_es;
718
719         if (sbi->s_log_groups_per_flex) {
720                 ret2 = find_group_flex(sb, dir, &group);
721                 if (ret2 == -1) {
722                         ret2 = find_group_other(sb, dir, &group);
723                         if (ret2 == 0 && once)
724                                 once = 0;
725                                 printk(KERN_NOTICE "ext4: find_group_flex "
726                                        "failed, fallback succeeded dir %lu\n",
727                                        dir->i_ino);
728                 }
729                 goto got_group;
730         }
731
732         if (S_ISDIR(mode)) {
733                 if (test_opt(sb, OLDALLOC))
734                         ret2 = find_group_dir(sb, dir, &group);
735                 else
736                         ret2 = find_group_orlov(sb, dir, &group);
737         } else
738                 ret2 = find_group_other(sb, dir, &group);
739
740 got_group:
741         err = -ENOSPC;
742         if (ret2 == -1)
743                 goto out;
744
745         for (i = 0; i < sbi->s_groups_count; i++) {
746                 err = -EIO;
747
748                 gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
749                 if (!gdp)
750                         goto fail;
751
752                 brelse(inode_bitmap_bh);
753                 inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
754                 if (!inode_bitmap_bh)
755                         goto fail;
756
757                 ino = 0;
758
759 repeat_in_this_group:
760                 ino = ext4_find_next_zero_bit((unsigned long *)
761                                               inode_bitmap_bh->b_data,
762                                               EXT4_INODES_PER_GROUP(sb), ino);
763
764                 if (ino < EXT4_INODES_PER_GROUP(sb)) {
765
766                         BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
767                         err = ext4_journal_get_write_access(handle,
768                                                             inode_bitmap_bh);
769                         if (err)
770                                 goto fail;
771
772                         BUFFER_TRACE(group_desc_bh, "get_write_access");
773                         err = ext4_journal_get_write_access(handle,
774                                                                 group_desc_bh);
775                         if (err)
776                                 goto fail;
777                         if (!ext4_claim_inode(sb, inode_bitmap_bh,
778                                                 ino, group, mode)) {
779                                 /* we won it */
780                                 BUFFER_TRACE(inode_bitmap_bh,
781                                         "call ext4_handle_dirty_metadata");
782                                 err = ext4_handle_dirty_metadata(handle,
783                                                                  inode,
784                                                         inode_bitmap_bh);
785                                 if (err)
786                                         goto fail;
787                                 /* zero bit is inode number 1*/
788                                 ino++;
789                                 goto got;
790                         }
791                         /* we lost it */
792                         ext4_handle_release_buffer(handle, inode_bitmap_bh);
793                         ext4_handle_release_buffer(handle, group_desc_bh);
794
795                         if (++ino < EXT4_INODES_PER_GROUP(sb))
796                                 goto repeat_in_this_group;
797                 }
798
799                 /*
800                  * This case is possible in concurrent environment.  It is very
801                  * rare.  We cannot repeat the find_group_xxx() call because
802                  * that will simply return the same blockgroup, because the
803                  * group descriptor metadata has not yet been updated.
804                  * So we just go onto the next blockgroup.
805                  */
806                 if (++group == sbi->s_groups_count)
807                         group = 0;
808         }
809         err = -ENOSPC;
810         goto out;
811
812 got:
813         /* We may have to initialize the block bitmap if it isn't already */
814         if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM) &&
815             gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
816                 struct buffer_head *block_bitmap_bh;
817
818                 block_bitmap_bh = ext4_read_block_bitmap(sb, group);
819                 BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
820                 err = ext4_journal_get_write_access(handle, block_bitmap_bh);
821                 if (err) {
822                         brelse(block_bitmap_bh);
823                         goto fail;
824                 }
825
826                 free = 0;
827                 spin_lock(sb_bgl_lock(sbi, group));
828                 /* recheck and clear flag under lock if we still need to */
829                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
830                         free = ext4_free_blocks_after_init(sb, group, gdp);
831                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
832                         ext4_free_blks_set(sb, gdp, free);
833                         gdp->bg_checksum = ext4_group_desc_csum(sbi, group,
834                                                                 gdp);
835                 }
836                 spin_unlock(sb_bgl_lock(sbi, group));
837
838                 /* Don't need to dirty bitmap block if we didn't change it */
839                 if (free) {
840                         BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
841                         err = ext4_handle_dirty_metadata(handle,
842                                                         NULL, block_bitmap_bh);
843                 }
844
845                 brelse(block_bitmap_bh);
846                 if (err)
847                         goto fail;
848         }
849         BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
850         err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
851         if (err)
852                 goto fail;
853
854         percpu_counter_dec(&sbi->s_freeinodes_counter);
855         if (S_ISDIR(mode))
856                 percpu_counter_inc(&sbi->s_dirs_counter);
857         sb->s_dirt = 1;
858
859         if (sbi->s_log_groups_per_flex) {
860                 flex_group = ext4_flex_group(sbi, group);
861                 spin_lock(sb_bgl_lock(sbi, flex_group));
862                 sbi->s_flex_groups[flex_group].free_inodes--;
863                 spin_unlock(sb_bgl_lock(sbi, flex_group));
864         }
865
866         inode->i_uid = current_fsuid();
867         if (test_opt(sb, GRPID))
868                 inode->i_gid = dir->i_gid;
869         else if (dir->i_mode & S_ISGID) {
870                 inode->i_gid = dir->i_gid;
871                 if (S_ISDIR(mode))
872                         mode |= S_ISGID;
873         } else
874                 inode->i_gid = current_fsgid();
875         inode->i_mode = mode;
876
877         inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
878         /* This is the optimal IO size (for stat), not the fs block size */
879         inode->i_blocks = 0;
880         inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
881                                                        ext4_current_time(inode);
882
883         memset(ei->i_data, 0, sizeof(ei->i_data));
884         ei->i_dir_start_lookup = 0;
885         ei->i_disksize = 0;
886
887         /*
888          * Don't inherit extent flag from directory. We set extent flag on
889          * newly created directory and file only if -o extent mount option is
890          * specified
891          */
892         ei->i_flags = EXT4_I(dir)->i_flags & ~(EXT4_INDEX_FL|EXT4_EXTENTS_FL);
893         if (S_ISLNK(mode))
894                 ei->i_flags &= ~(EXT4_IMMUTABLE_FL|EXT4_APPEND_FL);
895         /* dirsync only applies to directories */
896         if (!S_ISDIR(mode))
897                 ei->i_flags &= ~EXT4_DIRSYNC_FL;
898         ei->i_file_acl = 0;
899         ei->i_dtime = 0;
900         ei->i_block_group = group;
901
902         ext4_set_inode_flags(inode);
903         if (IS_DIRSYNC(inode))
904                 ext4_handle_sync(handle);
905         if (insert_inode_locked(inode) < 0) {
906                 err = -EINVAL;
907                 goto fail_drop;
908         }
909         spin_lock(&sbi->s_next_gen_lock);
910         inode->i_generation = sbi->s_next_generation++;
911         spin_unlock(&sbi->s_next_gen_lock);
912
913         ei->i_state = EXT4_STATE_NEW;
914
915         ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;
916
917         ret = inode;
918         if (DQUOT_ALLOC_INODE(inode)) {
919                 err = -EDQUOT;
920                 goto fail_drop;
921         }
922
923         err = ext4_init_acl(handle, inode, dir);
924         if (err)
925                 goto fail_free_drop;
926
927         err = ext4_init_security(handle, inode, dir);
928         if (err)
929                 goto fail_free_drop;
930
931         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
932                 /* set extent flag only for directory, file and normal symlink*/
933                 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
934                         EXT4_I(inode)->i_flags |= EXT4_EXTENTS_FL;
935                         ext4_ext_tree_init(handle, inode);
936                 }
937         }
938
939         err = ext4_mark_inode_dirty(handle, inode);
940         if (err) {
941                 ext4_std_error(sb, err);
942                 goto fail_free_drop;
943         }
944
945         ext4_debug("allocating inode %lu\n", inode->i_ino);
946         trace_mark(ext4_allocate_inode, "dev %s ino %lu dir %lu mode %d",
947                    sb->s_id, inode->i_ino, dir->i_ino, mode);
948         goto really_out;
949 fail:
950         ext4_std_error(sb, err);
951 out:
952         iput(inode);
953         ret = ERR_PTR(err);
954 really_out:
955         brelse(inode_bitmap_bh);
956         return ret;
957
958 fail_free_drop:
959         DQUOT_FREE_INODE(inode);
960
961 fail_drop:
962         DQUOT_DROP(inode);
963         inode->i_flags |= S_NOQUOTA;
964         inode->i_nlink = 0;
965         unlock_new_inode(inode);
966         iput(inode);
967         brelse(inode_bitmap_bh);
968         return ERR_PTR(err);
969 }
970
971 /* Verify that we are loading a valid orphan from disk */
972 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
973 {
974         unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
975         ext4_group_t block_group;
976         int bit;
977         struct buffer_head *bitmap_bh;
978         struct inode *inode = NULL;
979         long err = -EIO;
980
981         /* Error cases - e2fsck has already cleaned up for us */
982         if (ino > max_ino) {
983                 ext4_warning(sb, __func__,
984                              "bad orphan ino %lu!  e2fsck was run?", ino);
985                 goto error;
986         }
987
988         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
989         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
990         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
991         if (!bitmap_bh) {
992                 ext4_warning(sb, __func__,
993                              "inode bitmap error for orphan %lu", ino);
994                 goto error;
995         }
996
997         /* Having the inode bit set should be a 100% indicator that this
998          * is a valid orphan (no e2fsck run on fs).  Orphans also include
999          * inodes that were being truncated, so we can't check i_nlink==0.
1000          */
1001         if (!ext4_test_bit(bit, bitmap_bh->b_data))
1002                 goto bad_orphan;
1003
1004         inode = ext4_iget(sb, ino);
1005         if (IS_ERR(inode))
1006                 goto iget_failed;
1007
1008         /*
1009          * If the orphans has i_nlinks > 0 then it should be able to be
1010          * truncated, otherwise it won't be removed from the orphan list
1011          * during processing and an infinite loop will result.
1012          */
1013         if (inode->i_nlink && !ext4_can_truncate(inode))
1014                 goto bad_orphan;
1015
1016         if (NEXT_ORPHAN(inode) > max_ino)
1017                 goto bad_orphan;
1018         brelse(bitmap_bh);
1019         return inode;
1020
1021 iget_failed:
1022         err = PTR_ERR(inode);
1023         inode = NULL;
1024 bad_orphan:
1025         ext4_warning(sb, __func__,
1026                      "bad orphan inode %lu!  e2fsck was run?", ino);
1027         printk(KERN_NOTICE "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1028                bit, (unsigned long long)bitmap_bh->b_blocknr,
1029                ext4_test_bit(bit, bitmap_bh->b_data));
1030         printk(KERN_NOTICE "inode=%p\n", inode);
1031         if (inode) {
1032                 printk(KERN_NOTICE "is_bad_inode(inode)=%d\n",
1033                        is_bad_inode(inode));
1034                 printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
1035                        NEXT_ORPHAN(inode));
1036                 printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
1037                 printk(KERN_NOTICE "i_nlink=%u\n", inode->i_nlink);
1038                 /* Avoid freeing blocks if we got a bad deleted inode */
1039                 if (inode->i_nlink == 0)
1040                         inode->i_blocks = 0;
1041                 iput(inode);
1042         }
1043         brelse(bitmap_bh);
1044 error:
1045         return ERR_PTR(err);
1046 }
1047
1048 unsigned long ext4_count_free_inodes(struct super_block *sb)
1049 {
1050         unsigned long desc_count;
1051         struct ext4_group_desc *gdp;
1052         ext4_group_t i;
1053 #ifdef EXT4FS_DEBUG
1054         struct ext4_super_block *es;
1055         unsigned long bitmap_count, x;
1056         struct buffer_head *bitmap_bh = NULL;
1057
1058         es = EXT4_SB(sb)->s_es;
1059         desc_count = 0;
1060         bitmap_count = 0;
1061         gdp = NULL;
1062         for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
1063                 gdp = ext4_get_group_desc(sb, i, NULL);
1064                 if (!gdp)
1065                         continue;
1066                 desc_count += ext4_free_inodes_count(sb, gdp);
1067                 brelse(bitmap_bh);
1068                 bitmap_bh = ext4_read_inode_bitmap(sb, i);
1069                 if (!bitmap_bh)
1070                         continue;
1071
1072                 x = ext4_count_free(bitmap_bh, EXT4_INODES_PER_GROUP(sb) / 8);
1073                 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1074                         i, ext4_free_inodes_count(sb, gdp), x);
1075                 bitmap_count += x;
1076         }
1077         brelse(bitmap_bh);
1078         printk(KERN_DEBUG "ext4_count_free_inodes: "
1079                "stored = %u, computed = %lu, %lu\n",
1080                le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1081         return desc_count;
1082 #else
1083         desc_count = 0;
1084         for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
1085                 gdp = ext4_get_group_desc(sb, i, NULL);
1086                 if (!gdp)
1087                         continue;
1088                 desc_count += ext4_free_inodes_count(sb, gdp);
1089                 cond_resched();
1090         }
1091         return desc_count;
1092 #endif
1093 }
1094
1095 /* Called at mount-time, super-block is locked */
1096 unsigned long ext4_count_dirs(struct super_block * sb)
1097 {
1098         unsigned long count = 0;
1099         ext4_group_t i;
1100
1101         for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
1102                 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1103                 if (!gdp)
1104                         continue;
1105                 count += ext4_used_dirs_count(sb, gdp);
1106         }
1107         return count;
1108 }