Merge branch 'master' into next
[linux-3.10.git] / 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 %lu\n",
78                            block_group);
79                 gdp->bg_free_blocks_count = 0;
80                 gdp->bg_free_inodes_count = 0;
81                 gdp->bg_itable_unused = 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), EXT4_BLOCKS_PER_GROUP(sb),
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 = %lu, inode_bitmap = %llu",
115                             block_group, bitmap_blk);
116                 return NULL;
117         }
118         if (buffer_uptodate(bh) &&
119             !(desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)))
120                 return bh;
121
122         lock_buffer(bh);
123         spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));
124         if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
125                 ext4_init_inode_bitmap(sb, bh, block_group, desc);
126                 set_buffer_uptodate(bh);
127                 unlock_buffer(bh);
128                 spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
129                 return bh;
130         }
131         spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
132         if (bh_submit_read(bh) < 0) {
133                 put_bh(bh);
134                 ext4_error(sb, __func__,
135                             "Cannot read inode bitmap - "
136                             "block_group = %lu, inode_bitmap = %llu",
137                             block_group, bitmap_blk);
138                 return NULL;
139         }
140         return bh;
141 }
142
143 /*
144  * NOTE! When we get the inode, we're the only people
145  * that have access to it, and as such there are no
146  * race conditions we have to worry about. The inode
147  * is not on the hash-lists, and it cannot be reached
148  * through the filesystem because the directory entry
149  * has been deleted earlier.
150  *
151  * HOWEVER: we must make sure that we get no aliases,
152  * which means that we have to call "clear_inode()"
153  * _before_ we mark the inode not in use in the inode
154  * bitmaps. Otherwise a newly created file might use
155  * the same inode number (not actually the same pointer
156  * though), and then we'd have two inodes sharing the
157  * same inode number and space on the harddisk.
158  */
159 void ext4_free_inode(handle_t *handle, struct inode *inode)
160 {
161         struct super_block *sb = inode->i_sb;
162         int is_directory;
163         unsigned long ino;
164         struct buffer_head *bitmap_bh = NULL;
165         struct buffer_head *bh2;
166         ext4_group_t block_group;
167         unsigned long bit;
168         struct ext4_group_desc *gdp;
169         struct ext4_super_block *es;
170         struct ext4_sb_info *sbi;
171         int fatal = 0, err;
172         ext4_group_t flex_group;
173
174         if (atomic_read(&inode->i_count) > 1) {
175                 printk(KERN_ERR "ext4_free_inode: inode has count=%d\n",
176                        atomic_read(&inode->i_count));
177                 return;
178         }
179         if (inode->i_nlink) {
180                 printk(KERN_ERR "ext4_free_inode: inode has nlink=%d\n",
181                        inode->i_nlink);
182                 return;
183         }
184         if (!sb) {
185                 printk(KERN_ERR "ext4_free_inode: inode on "
186                        "nonexistent device\n");
187                 return;
188         }
189         sbi = EXT4_SB(sb);
190
191         ino = inode->i_ino;
192         ext4_debug("freeing inode %lu\n", ino);
193
194         /*
195          * Note: we must free any quota before locking the superblock,
196          * as writing the quota to disk may need the lock as well.
197          */
198         DQUOT_INIT(inode);
199         ext4_xattr_delete_inode(handle, inode);
200         DQUOT_FREE_INODE(inode);
201         DQUOT_DROP(inode);
202
203         is_directory = S_ISDIR(inode->i_mode);
204
205         /* Do this BEFORE marking the inode not in use or returning an error */
206         clear_inode(inode);
207
208         es = EXT4_SB(sb)->s_es;
209         if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
210                 ext4_error(sb, "ext4_free_inode",
211                            "reserved or nonexistent inode %lu", ino);
212                 goto error_return;
213         }
214         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
215         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
216         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
217         if (!bitmap_bh)
218                 goto error_return;
219
220         BUFFER_TRACE(bitmap_bh, "get_write_access");
221         fatal = ext4_journal_get_write_access(handle, bitmap_bh);
222         if (fatal)
223                 goto error_return;
224
225         /* Ok, now we can actually update the inode bitmaps.. */
226         if (!ext4_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
227                                         bit, bitmap_bh->b_data))
228                 ext4_error(sb, "ext4_free_inode",
229                            "bit already cleared for inode %lu", ino);
230         else {
231                 gdp = ext4_get_group_desc(sb, block_group, &bh2);
232
233                 BUFFER_TRACE(bh2, "get_write_access");
234                 fatal = ext4_journal_get_write_access(handle, bh2);
235                 if (fatal) goto error_return;
236
237                 if (gdp) {
238                         spin_lock(sb_bgl_lock(sbi, block_group));
239                         le16_add_cpu(&gdp->bg_free_inodes_count, 1);
240                         if (is_directory)
241                                 le16_add_cpu(&gdp->bg_used_dirs_count, -1);
242                         gdp->bg_checksum = ext4_group_desc_csum(sbi,
243                                                         block_group, gdp);
244                         spin_unlock(sb_bgl_lock(sbi, block_group));
245                         percpu_counter_inc(&sbi->s_freeinodes_counter);
246                         if (is_directory)
247                                 percpu_counter_dec(&sbi->s_dirs_counter);
248
249                         if (sbi->s_log_groups_per_flex) {
250                                 flex_group = ext4_flex_group(sbi, block_group);
251                                 spin_lock(sb_bgl_lock(sbi, flex_group));
252                                 sbi->s_flex_groups[flex_group].free_inodes++;
253                                 spin_unlock(sb_bgl_lock(sbi, flex_group));
254                         }
255                 }
256                 BUFFER_TRACE(bh2, "call ext4_journal_dirty_metadata");
257                 err = ext4_journal_dirty_metadata(handle, bh2);
258                 if (!fatal) fatal = err;
259         }
260         BUFFER_TRACE(bitmap_bh, "call ext4_journal_dirty_metadata");
261         err = ext4_journal_dirty_metadata(handle, bitmap_bh);
262         if (!fatal)
263                 fatal = err;
264         sb->s_dirt = 1;
265 error_return:
266         brelse(bitmap_bh);
267         ext4_std_error(sb, fatal);
268 }
269
270 /*
271  * There are two policies for allocating an inode.  If the new inode is
272  * a directory, then a forward search is made for a block group with both
273  * free space and a low directory-to-inode ratio; if that fails, then of
274  * the groups with above-average free space, that group with the fewest
275  * directories already is chosen.
276  *
277  * For other inodes, search forward from the parent directory\'s block
278  * group to find a free inode.
279  */
280 static int find_group_dir(struct super_block *sb, struct inode *parent,
281                                 ext4_group_t *best_group)
282 {
283         ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
284         unsigned int freei, avefreei;
285         struct ext4_group_desc *desc, *best_desc = NULL;
286         ext4_group_t group;
287         int ret = -1;
288
289         freei = percpu_counter_read_positive(&EXT4_SB(sb)->s_freeinodes_counter);
290         avefreei = freei / ngroups;
291
292         for (group = 0; group < ngroups; group++) {
293                 desc = ext4_get_group_desc(sb, group, NULL);
294                 if (!desc || !desc->bg_free_inodes_count)
295                         continue;
296                 if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
297                         continue;
298                 if (!best_desc ||
299                     (le16_to_cpu(desc->bg_free_blocks_count) >
300                      le16_to_cpu(best_desc->bg_free_blocks_count))) {
301                         *best_group = group;
302                         best_desc = desc;
303                         ret = 0;
304                 }
305         }
306         return ret;
307 }
308
309 #define free_block_ratio 10
310
311 static int find_group_flex(struct super_block *sb, struct inode *parent,
312                            ext4_group_t *best_group)
313 {
314         struct ext4_sb_info *sbi = EXT4_SB(sb);
315         struct ext4_group_desc *desc;
316         struct buffer_head *bh;
317         struct flex_groups *flex_group = sbi->s_flex_groups;
318         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
319         ext4_group_t parent_fbg_group = ext4_flex_group(sbi, parent_group);
320         ext4_group_t ngroups = sbi->s_groups_count;
321         int flex_size = ext4_flex_bg_size(sbi);
322         ext4_group_t best_flex = parent_fbg_group;
323         int blocks_per_flex = sbi->s_blocks_per_group * flex_size;
324         int flexbg_free_blocks;
325         int flex_freeb_ratio;
326         ext4_group_t n_fbg_groups;
327         ext4_group_t i;
328
329         n_fbg_groups = (sbi->s_groups_count + flex_size - 1) >>
330                 sbi->s_log_groups_per_flex;
331
332 find_close_to_parent:
333         flexbg_free_blocks = flex_group[best_flex].free_blocks;
334         flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
335         if (flex_group[best_flex].free_inodes &&
336             flex_freeb_ratio > free_block_ratio)
337                 goto found_flexbg;
338
339         if (best_flex && best_flex == parent_fbg_group) {
340                 best_flex--;
341                 goto find_close_to_parent;
342         }
343
344         for (i = 0; i < n_fbg_groups; i++) {
345                 if (i == parent_fbg_group || i == parent_fbg_group - 1)
346                         continue;
347
348                 flexbg_free_blocks = flex_group[i].free_blocks;
349                 flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
350
351                 if (flex_freeb_ratio > free_block_ratio &&
352                     flex_group[i].free_inodes) {
353                         best_flex = i;
354                         goto found_flexbg;
355                 }
356
357                 if (flex_group[best_flex].free_inodes == 0 ||
358                     (flex_group[i].free_blocks >
359                      flex_group[best_flex].free_blocks &&
360                      flex_group[i].free_inodes))
361                         best_flex = i;
362         }
363
364         if (!flex_group[best_flex].free_inodes ||
365             !flex_group[best_flex].free_blocks)
366                 return -1;
367
368 found_flexbg:
369         for (i = best_flex * flex_size; i < ngroups &&
370                      i < (best_flex + 1) * flex_size; i++) {
371                 desc = ext4_get_group_desc(sb, i, &bh);
372                 if (le16_to_cpu(desc->bg_free_inodes_count)) {
373                         *best_group = i;
374                         goto out;
375                 }
376         }
377
378         return -1;
379 out:
380         return 0;
381 }
382
383 /*
384  * Orlov's allocator for directories.
385  *
386  * We always try to spread first-level directories.
387  *
388  * If there are blockgroups with both free inodes and free blocks counts
389  * not worse than average we return one with smallest directory count.
390  * Otherwise we simply return a random group.
391  *
392  * For the rest rules look so:
393  *
394  * It's OK to put directory into a group unless
395  * it has too many directories already (max_dirs) or
396  * it has too few free inodes left (min_inodes) or
397  * it has too few free blocks left (min_blocks) or
398  * it's already running too large debt (max_debt).
399  * Parent's group is preferred, if it doesn't satisfy these
400  * conditions we search cyclically through the rest. If none
401  * of the groups look good we just look for a group with more
402  * free inodes than average (starting at parent's group).
403  *
404  * Debt is incremented each time we allocate a directory and decremented
405  * when we allocate an inode, within 0--255.
406  */
407
408 #define INODE_COST 64
409 #define BLOCK_COST 256
410
411 static int find_group_orlov(struct super_block *sb, struct inode *parent,
412                                 ext4_group_t *group)
413 {
414         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
415         struct ext4_sb_info *sbi = EXT4_SB(sb);
416         struct ext4_super_block *es = sbi->s_es;
417         ext4_group_t ngroups = sbi->s_groups_count;
418         int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
419         unsigned int freei, avefreei;
420         ext4_fsblk_t freeb, avefreeb;
421         ext4_fsblk_t blocks_per_dir;
422         unsigned int ndirs;
423         int max_debt, max_dirs, min_inodes;
424         ext4_grpblk_t min_blocks;
425         ext4_group_t i;
426         struct ext4_group_desc *desc;
427
428         freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
429         avefreei = freei / ngroups;
430         freeb = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
431         avefreeb = freeb;
432         do_div(avefreeb, ngroups);
433         ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
434
435         if ((parent == sb->s_root->d_inode) ||
436             (EXT4_I(parent)->i_flags & EXT4_TOPDIR_FL)) {
437                 int best_ndir = inodes_per_group;
438                 ext4_group_t grp;
439                 int ret = -1;
440
441                 get_random_bytes(&grp, sizeof(grp));
442                 parent_group = (unsigned)grp % ngroups;
443                 for (i = 0; i < ngroups; i++) {
444                         grp = (parent_group + i) % ngroups;
445                         desc = ext4_get_group_desc(sb, grp, NULL);
446                         if (!desc || !desc->bg_free_inodes_count)
447                                 continue;
448                         if (le16_to_cpu(desc->bg_used_dirs_count) >= best_ndir)
449                                 continue;
450                         if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
451                                 continue;
452                         if (le16_to_cpu(desc->bg_free_blocks_count) < avefreeb)
453                                 continue;
454                         *group = grp;
455                         ret = 0;
456                         best_ndir = le16_to_cpu(desc->bg_used_dirs_count);
457                 }
458                 if (ret == 0)
459                         return ret;
460                 goto fallback;
461         }
462
463         blocks_per_dir = ext4_blocks_count(es) - freeb;
464         do_div(blocks_per_dir, ndirs);
465
466         max_dirs = ndirs / ngroups + inodes_per_group / 16;
467         min_inodes = avefreei - inodes_per_group / 4;
468         min_blocks = avefreeb - EXT4_BLOCKS_PER_GROUP(sb) / 4;
469
470         max_debt = EXT4_BLOCKS_PER_GROUP(sb);
471         max_debt /= max_t(int, blocks_per_dir, BLOCK_COST);
472         if (max_debt * INODE_COST > inodes_per_group)
473                 max_debt = inodes_per_group / INODE_COST;
474         if (max_debt > 255)
475                 max_debt = 255;
476         if (max_debt == 0)
477                 max_debt = 1;
478
479         for (i = 0; i < ngroups; i++) {
480                 *group = (parent_group + i) % ngroups;
481                 desc = ext4_get_group_desc(sb, *group, NULL);
482                 if (!desc || !desc->bg_free_inodes_count)
483                         continue;
484                 if (le16_to_cpu(desc->bg_used_dirs_count) >= max_dirs)
485                         continue;
486                 if (le16_to_cpu(desc->bg_free_inodes_count) < min_inodes)
487                         continue;
488                 if (le16_to_cpu(desc->bg_free_blocks_count) < min_blocks)
489                         continue;
490                 return 0;
491         }
492
493 fallback:
494         for (i = 0; i < ngroups; i++) {
495                 *group = (parent_group + i) % ngroups;
496                 desc = ext4_get_group_desc(sb, *group, NULL);
497                 if (desc && desc->bg_free_inodes_count &&
498                         le16_to_cpu(desc->bg_free_inodes_count) >= avefreei)
499                         return 0;
500         }
501
502         if (avefreei) {
503                 /*
504                  * The free-inodes counter is approximate, and for really small
505                  * filesystems the above test can fail to find any blockgroups
506                  */
507                 avefreei = 0;
508                 goto fallback;
509         }
510
511         return -1;
512 }
513
514 static int find_group_other(struct super_block *sb, struct inode *parent,
515                                 ext4_group_t *group)
516 {
517         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
518         ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
519         struct ext4_group_desc *desc;
520         ext4_group_t i;
521
522         /*
523          * Try to place the inode in its parent directory
524          */
525         *group = parent_group;
526         desc = ext4_get_group_desc(sb, *group, NULL);
527         if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
528                         le16_to_cpu(desc->bg_free_blocks_count))
529                 return 0;
530
531         /*
532          * We're going to place this inode in a different blockgroup from its
533          * parent.  We want to cause files in a common directory to all land in
534          * the same blockgroup.  But we want files which are in a different
535          * directory which shares a blockgroup with our parent to land in a
536          * different blockgroup.
537          *
538          * So add our directory's i_ino into the starting point for the hash.
539          */
540         *group = (*group + parent->i_ino) % ngroups;
541
542         /*
543          * Use a quadratic hash to find a group with a free inode and some free
544          * blocks.
545          */
546         for (i = 1; i < ngroups; i <<= 1) {
547                 *group += i;
548                 if (*group >= ngroups)
549                         *group -= ngroups;
550                 desc = ext4_get_group_desc(sb, *group, NULL);
551                 if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
552                                 le16_to_cpu(desc->bg_free_blocks_count))
553                         return 0;
554         }
555
556         /*
557          * That failed: try linear search for a free inode, even if that group
558          * has no free blocks.
559          */
560         *group = parent_group;
561         for (i = 0; i < ngroups; i++) {
562                 if (++*group >= ngroups)
563                         *group = 0;
564                 desc = ext4_get_group_desc(sb, *group, NULL);
565                 if (desc && le16_to_cpu(desc->bg_free_inodes_count))
566                         return 0;
567         }
568
569         return -1;
570 }
571
572 /*
573  * There are two policies for allocating an inode.  If the new inode is
574  * a directory, then a forward search is made for a block group with both
575  * free space and a low directory-to-inode ratio; if that fails, then of
576  * the groups with above-average free space, that group with the fewest
577  * directories already is chosen.
578  *
579  * For other inodes, search forward from the parent directory's block
580  * group to find a free inode.
581  */
582 struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, int mode)
583 {
584         struct super_block *sb;
585         struct buffer_head *bitmap_bh = NULL;
586         struct buffer_head *bh2;
587         ext4_group_t group = 0;
588         unsigned long ino = 0;
589         struct inode *inode;
590         struct ext4_group_desc *gdp = NULL;
591         struct ext4_super_block *es;
592         struct ext4_inode_info *ei;
593         struct ext4_sb_info *sbi;
594         int ret2, err = 0;
595         struct inode *ret;
596         ext4_group_t i;
597         int free = 0;
598         ext4_group_t flex_group;
599
600         /* Cannot create files in a deleted directory */
601         if (!dir || !dir->i_nlink)
602                 return ERR_PTR(-EPERM);
603
604         sb = dir->i_sb;
605         inode = new_inode(sb);
606         if (!inode)
607                 return ERR_PTR(-ENOMEM);
608         ei = EXT4_I(inode);
609
610         sbi = EXT4_SB(sb);
611         es = sbi->s_es;
612
613         if (sbi->s_log_groups_per_flex) {
614                 ret2 = find_group_flex(sb, dir, &group);
615                 goto got_group;
616         }
617
618         if (S_ISDIR(mode)) {
619                 if (test_opt(sb, OLDALLOC))
620                         ret2 = find_group_dir(sb, dir, &group);
621                 else
622                         ret2 = find_group_orlov(sb, dir, &group);
623         } else
624                 ret2 = find_group_other(sb, dir, &group);
625
626 got_group:
627         err = -ENOSPC;
628         if (ret2 == -1)
629                 goto out;
630
631         for (i = 0; i < sbi->s_groups_count; i++) {
632                 err = -EIO;
633
634                 gdp = ext4_get_group_desc(sb, group, &bh2);
635                 if (!gdp)
636                         goto fail;
637
638                 brelse(bitmap_bh);
639                 bitmap_bh = ext4_read_inode_bitmap(sb, group);
640                 if (!bitmap_bh)
641                         goto fail;
642
643                 ino = 0;
644
645 repeat_in_this_group:
646                 ino = ext4_find_next_zero_bit((unsigned long *)
647                                 bitmap_bh->b_data, EXT4_INODES_PER_GROUP(sb), ino);
648                 if (ino < EXT4_INODES_PER_GROUP(sb)) {
649
650                         BUFFER_TRACE(bitmap_bh, "get_write_access");
651                         err = ext4_journal_get_write_access(handle, bitmap_bh);
652                         if (err)
653                                 goto fail;
654
655                         if (!ext4_set_bit_atomic(sb_bgl_lock(sbi, group),
656                                                 ino, bitmap_bh->b_data)) {
657                                 /* we won it */
658                                 BUFFER_TRACE(bitmap_bh,
659                                         "call ext4_journal_dirty_metadata");
660                                 err = ext4_journal_dirty_metadata(handle,
661                                                                 bitmap_bh);
662                                 if (err)
663                                         goto fail;
664                                 goto got;
665                         }
666                         /* we lost it */
667                         jbd2_journal_release_buffer(handle, bitmap_bh);
668
669                         if (++ino < EXT4_INODES_PER_GROUP(sb))
670                                 goto repeat_in_this_group;
671                 }
672
673                 /*
674                  * This case is possible in concurrent environment.  It is very
675                  * rare.  We cannot repeat the find_group_xxx() call because
676                  * that will simply return the same blockgroup, because the
677                  * group descriptor metadata has not yet been updated.
678                  * So we just go onto the next blockgroup.
679                  */
680                 if (++group == sbi->s_groups_count)
681                         group = 0;
682         }
683         err = -ENOSPC;
684         goto out;
685
686 got:
687         ino++;
688         if ((group == 0 && ino < EXT4_FIRST_INO(sb)) ||
689             ino > EXT4_INODES_PER_GROUP(sb)) {
690                 ext4_error(sb, __func__,
691                            "reserved inode or inode > inodes count - "
692                            "block_group = %lu, inode=%lu", group,
693                            ino + group * EXT4_INODES_PER_GROUP(sb));
694                 err = -EIO;
695                 goto fail;
696         }
697
698         BUFFER_TRACE(bh2, "get_write_access");
699         err = ext4_journal_get_write_access(handle, bh2);
700         if (err) goto fail;
701
702         /* We may have to initialize the block bitmap if it isn't already */
703         if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM) &&
704             gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
705                 struct buffer_head *block_bh = ext4_read_block_bitmap(sb, group);
706
707                 BUFFER_TRACE(block_bh, "get block bitmap access");
708                 err = ext4_journal_get_write_access(handle, block_bh);
709                 if (err) {
710                         brelse(block_bh);
711                         goto fail;
712                 }
713
714                 free = 0;
715                 spin_lock(sb_bgl_lock(sbi, group));
716                 /* recheck and clear flag under lock if we still need to */
717                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
718                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
719                         free = ext4_free_blocks_after_init(sb, group, gdp);
720                         gdp->bg_free_blocks_count = cpu_to_le16(free);
721                         gdp->bg_checksum = ext4_group_desc_csum(sbi, group,
722                                                                 gdp);
723                 }
724                 spin_unlock(sb_bgl_lock(sbi, group));
725
726                 /* Don't need to dirty bitmap block if we didn't change it */
727                 if (free) {
728                         BUFFER_TRACE(block_bh, "dirty block bitmap");
729                         err = ext4_journal_dirty_metadata(handle, block_bh);
730                 }
731
732                 brelse(block_bh);
733                 if (err)
734                         goto fail;
735         }
736
737         spin_lock(sb_bgl_lock(sbi, group));
738         /* If we didn't allocate from within the initialized part of the inode
739          * table then we need to initialize up to this inode. */
740         if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
741                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
742                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
743
744                         /* When marking the block group with
745                          * ~EXT4_BG_INODE_UNINIT we don't want to depend
746                          * on the value of bg_itable_unused even though
747                          * mke2fs could have initialized the same for us.
748                          * Instead we calculated the value below
749                          */
750
751                         free = 0;
752                 } else {
753                         free = EXT4_INODES_PER_GROUP(sb) -
754                                 le16_to_cpu(gdp->bg_itable_unused);
755                 }
756
757                 /*
758                  * Check the relative inode number against the last used
759                  * relative inode number in this group. if it is greater
760                  * we need to  update the bg_itable_unused count
761                  *
762                  */
763                 if (ino > free)
764                         gdp->bg_itable_unused =
765                                 cpu_to_le16(EXT4_INODES_PER_GROUP(sb) - ino);
766         }
767
768         le16_add_cpu(&gdp->bg_free_inodes_count, -1);
769         if (S_ISDIR(mode)) {
770                 le16_add_cpu(&gdp->bg_used_dirs_count, 1);
771         }
772         gdp->bg_checksum = ext4_group_desc_csum(sbi, group, gdp);
773         spin_unlock(sb_bgl_lock(sbi, group));
774         BUFFER_TRACE(bh2, "call ext4_journal_dirty_metadata");
775         err = ext4_journal_dirty_metadata(handle, bh2);
776         if (err) goto fail;
777
778         percpu_counter_dec(&sbi->s_freeinodes_counter);
779         if (S_ISDIR(mode))
780                 percpu_counter_inc(&sbi->s_dirs_counter);
781         sb->s_dirt = 1;
782
783         if (sbi->s_log_groups_per_flex) {
784                 flex_group = ext4_flex_group(sbi, group);
785                 spin_lock(sb_bgl_lock(sbi, flex_group));
786                 sbi->s_flex_groups[flex_group].free_inodes--;
787                 spin_unlock(sb_bgl_lock(sbi, flex_group));
788         }
789
790         inode->i_uid = current_fsuid();
791         if (test_opt(sb, GRPID))
792                 inode->i_gid = dir->i_gid;
793         else if (dir->i_mode & S_ISGID) {
794                 inode->i_gid = dir->i_gid;
795                 if (S_ISDIR(mode))
796                         mode |= S_ISGID;
797         } else
798                 inode->i_gid = current_fsgid();
799         inode->i_mode = mode;
800
801         inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
802         /* This is the optimal IO size (for stat), not the fs block size */
803         inode->i_blocks = 0;
804         inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
805                                                        ext4_current_time(inode);
806
807         memset(ei->i_data, 0, sizeof(ei->i_data));
808         ei->i_dir_start_lookup = 0;
809         ei->i_disksize = 0;
810
811         /*
812          * Don't inherit extent flag from directory. We set extent flag on
813          * newly created directory and file only if -o extent mount option is
814          * specified
815          */
816         ei->i_flags = EXT4_I(dir)->i_flags & ~(EXT4_INDEX_FL|EXT4_EXTENTS_FL);
817         if (S_ISLNK(mode))
818                 ei->i_flags &= ~(EXT4_IMMUTABLE_FL|EXT4_APPEND_FL);
819         /* dirsync only applies to directories */
820         if (!S_ISDIR(mode))
821                 ei->i_flags &= ~EXT4_DIRSYNC_FL;
822         ei->i_file_acl = 0;
823         ei->i_dtime = 0;
824         ei->i_block_group = group;
825
826         ext4_set_inode_flags(inode);
827         if (IS_DIRSYNC(inode))
828                 handle->h_sync = 1;
829         insert_inode_hash(inode);
830         spin_lock(&sbi->s_next_gen_lock);
831         inode->i_generation = sbi->s_next_generation++;
832         spin_unlock(&sbi->s_next_gen_lock);
833
834         ei->i_state = EXT4_STATE_NEW;
835
836         ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;
837
838         ret = inode;
839         if (DQUOT_ALLOC_INODE(inode)) {
840                 err = -EDQUOT;
841                 goto fail_drop;
842         }
843
844         err = ext4_init_acl(handle, inode, dir);
845         if (err)
846                 goto fail_free_drop;
847
848         err = ext4_init_security(handle, inode, dir);
849         if (err)
850                 goto fail_free_drop;
851
852         if (test_opt(sb, EXTENTS)) {
853                 /* set extent flag only for directory, file and normal symlink*/
854                 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
855                         EXT4_I(inode)->i_flags |= EXT4_EXTENTS_FL;
856                         ext4_ext_tree_init(handle, inode);
857                 }
858         }
859
860         err = ext4_mark_inode_dirty(handle, inode);
861         if (err) {
862                 ext4_std_error(sb, err);
863                 goto fail_free_drop;
864         }
865
866         ext4_debug("allocating inode %lu\n", inode->i_ino);
867         goto really_out;
868 fail:
869         ext4_std_error(sb, err);
870 out:
871         iput(inode);
872         ret = ERR_PTR(err);
873 really_out:
874         brelse(bitmap_bh);
875         return ret;
876
877 fail_free_drop:
878         DQUOT_FREE_INODE(inode);
879
880 fail_drop:
881         DQUOT_DROP(inode);
882         inode->i_flags |= S_NOQUOTA;
883         inode->i_nlink = 0;
884         iput(inode);
885         brelse(bitmap_bh);
886         return ERR_PTR(err);
887 }
888
889 /* Verify that we are loading a valid orphan from disk */
890 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
891 {
892         unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
893         ext4_group_t block_group;
894         int bit;
895         struct buffer_head *bitmap_bh;
896         struct inode *inode = NULL;
897         long err = -EIO;
898
899         /* Error cases - e2fsck has already cleaned up for us */
900         if (ino > max_ino) {
901                 ext4_warning(sb, __func__,
902                              "bad orphan ino %lu!  e2fsck was run?", ino);
903                 goto error;
904         }
905
906         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
907         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
908         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
909         if (!bitmap_bh) {
910                 ext4_warning(sb, __func__,
911                              "inode bitmap error for orphan %lu", ino);
912                 goto error;
913         }
914
915         /* Having the inode bit set should be a 100% indicator that this
916          * is a valid orphan (no e2fsck run on fs).  Orphans also include
917          * inodes that were being truncated, so we can't check i_nlink==0.
918          */
919         if (!ext4_test_bit(bit, bitmap_bh->b_data))
920                 goto bad_orphan;
921
922         inode = ext4_iget(sb, ino);
923         if (IS_ERR(inode))
924                 goto iget_failed;
925
926         /*
927          * If the orphans has i_nlinks > 0 then it should be able to be
928          * truncated, otherwise it won't be removed from the orphan list
929          * during processing and an infinite loop will result.
930          */
931         if (inode->i_nlink && !ext4_can_truncate(inode))
932                 goto bad_orphan;
933
934         if (NEXT_ORPHAN(inode) > max_ino)
935                 goto bad_orphan;
936         brelse(bitmap_bh);
937         return inode;
938
939 iget_failed:
940         err = PTR_ERR(inode);
941         inode = NULL;
942 bad_orphan:
943         ext4_warning(sb, __func__,
944                      "bad orphan inode %lu!  e2fsck was run?", ino);
945         printk(KERN_NOTICE "ext4_test_bit(bit=%d, block=%llu) = %d\n",
946                bit, (unsigned long long)bitmap_bh->b_blocknr,
947                ext4_test_bit(bit, bitmap_bh->b_data));
948         printk(KERN_NOTICE "inode=%p\n", inode);
949         if (inode) {
950                 printk(KERN_NOTICE "is_bad_inode(inode)=%d\n",
951                        is_bad_inode(inode));
952                 printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
953                        NEXT_ORPHAN(inode));
954                 printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
955                 printk(KERN_NOTICE "i_nlink=%u\n", inode->i_nlink);
956                 /* Avoid freeing blocks if we got a bad deleted inode */
957                 if (inode->i_nlink == 0)
958                         inode->i_blocks = 0;
959                 iput(inode);
960         }
961         brelse(bitmap_bh);
962 error:
963         return ERR_PTR(err);
964 }
965
966 unsigned long ext4_count_free_inodes(struct super_block *sb)
967 {
968         unsigned long desc_count;
969         struct ext4_group_desc *gdp;
970         ext4_group_t i;
971 #ifdef EXT4FS_DEBUG
972         struct ext4_super_block *es;
973         unsigned long bitmap_count, x;
974         struct buffer_head *bitmap_bh = NULL;
975
976         es = EXT4_SB(sb)->s_es;
977         desc_count = 0;
978         bitmap_count = 0;
979         gdp = NULL;
980         for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
981                 gdp = ext4_get_group_desc(sb, i, NULL);
982                 if (!gdp)
983                         continue;
984                 desc_count += le16_to_cpu(gdp->bg_free_inodes_count);
985                 brelse(bitmap_bh);
986                 bitmap_bh = ext4_read_inode_bitmap(sb, i);
987                 if (!bitmap_bh)
988                         continue;
989
990                 x = ext4_count_free(bitmap_bh, EXT4_INODES_PER_GROUP(sb) / 8);
991                 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
992                         i, le16_to_cpu(gdp->bg_free_inodes_count), x);
993                 bitmap_count += x;
994         }
995         brelse(bitmap_bh);
996         printk(KERN_DEBUG "ext4_count_free_inodes: "
997                "stored = %u, computed = %lu, %lu\n",
998                le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
999         return desc_count;
1000 #else
1001         desc_count = 0;
1002         for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
1003                 gdp = ext4_get_group_desc(sb, i, NULL);
1004                 if (!gdp)
1005                         continue;
1006                 desc_count += le16_to_cpu(gdp->bg_free_inodes_count);
1007                 cond_resched();
1008         }
1009         return desc_count;
1010 #endif
1011 }
1012
1013 /* Called at mount-time, super-block is locked */
1014 unsigned long ext4_count_dirs(struct super_block * sb)
1015 {
1016         unsigned long count = 0;
1017         ext4_group_t i;
1018
1019         for (i = 0; i < EXT4_SB(sb)->s_groups_count; i++) {
1020                 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1021                 if (!gdp)
1022                         continue;
1023                 count += le16_to_cpu(gdp->bg_used_dirs_count);
1024         }
1025         return count;
1026 }
1027