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Linux/fs/ext4/ialloc.c

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  *  linux/fs/ext4/ialloc.c
  4  *
  5  * Copyright (C) 1992, 1993, 1994, 1995
  6  * Remy Card (card@masi.ibp.fr)
  7  * Laboratoire MASI - Institut Blaise Pascal
  8  * Universite Pierre et Marie Curie (Paris VI)
  9  *
 10  *  BSD ufs-inspired inode and directory allocation by
 11  *  Stephen Tweedie (sct@redhat.com), 1993
 12  *  Big-endian to little-endian byte-swapping/bitmaps by
 13  *        David S. Miller (davem@caip.rutgers.edu), 1995
 14  */
 15 
 16 #include <linux/time.h>
 17 #include <linux/fs.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 <linux/cred.h>
 26 
 27 #include <asm/byteorder.h>
 28 
 29 #include "ext4.h"
 30 #include "ext4_jbd2.h"
 31 #include "xattr.h"
 32 #include "acl.h"
 33 
 34 #include <trace/events/ext4.h>
 35 
 36 /*
 37  * ialloc.c contains the inodes allocation and deallocation routines
 38  */
 39 
 40 /*
 41  * The free inodes are managed by bitmaps.  A file system contains several
 42  * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
 43  * block for inodes, N blocks for the inode table and data blocks.
 44  *
 45  * The file system contains group descriptors which are located after the
 46  * super block.  Each descriptor contains the number of the bitmap block and
 47  * the free blocks count in the block.
 48  */
 49 
 50 /*
 51  * To avoid calling the atomic setbit hundreds or thousands of times, we only
 52  * need to use it within a single byte (to ensure we get endianness right).
 53  * We can use memset for the rest of the bitmap as there are no other users.
 54  */
 55 void ext4_mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
 56 {
 57         int i;
 58 
 59         if (start_bit >= end_bit)
 60                 return;
 61 
 62         ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
 63         for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
 64                 ext4_set_bit(i, bitmap);
 65         if (i < end_bit)
 66                 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
 67 }
 68 
 69 void ext4_end_bitmap_read(struct buffer_head *bh, int uptodate)
 70 {
 71         if (uptodate) {
 72                 set_buffer_uptodate(bh);
 73                 set_bitmap_uptodate(bh);
 74         }
 75         unlock_buffer(bh);
 76         put_bh(bh);
 77 }
 78 
 79 static int ext4_validate_inode_bitmap(struct super_block *sb,
 80                                       struct ext4_group_desc *desc,
 81                                       ext4_group_t block_group,
 82                                       struct buffer_head *bh)
 83 {
 84         ext4_fsblk_t    blk;
 85         struct ext4_group_info *grp = ext4_get_group_info(sb, block_group);
 86 
 87         if (buffer_verified(bh))
 88                 return 0;
 89         if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
 90                 return -EFSCORRUPTED;
 91 
 92         ext4_lock_group(sb, block_group);
 93         if (buffer_verified(bh))
 94                 goto verified;
 95         blk = ext4_inode_bitmap(sb, desc);
 96         if (!ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh,
 97                                            EXT4_INODES_PER_GROUP(sb) / 8)) {
 98                 ext4_unlock_group(sb, block_group);
 99                 ext4_error(sb, "Corrupt inode bitmap - block_group = %u, "
100                            "inode_bitmap = %llu", block_group, blk);
101                 ext4_mark_group_bitmap_corrupted(sb, block_group,
102                                         EXT4_GROUP_INFO_IBITMAP_CORRUPT);
103                 return -EFSBADCRC;
104         }
105         set_buffer_verified(bh);
106 verified:
107         ext4_unlock_group(sb, block_group);
108         return 0;
109 }
110 
111 /*
112  * Read the inode allocation bitmap for a given block_group, reading
113  * into the specified slot in the superblock's bitmap cache.
114  *
115  * Return buffer_head of bitmap on success or NULL.
116  */
117 static struct buffer_head *
118 ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
119 {
120         struct ext4_group_desc *desc;
121         struct ext4_sb_info *sbi = EXT4_SB(sb);
122         struct buffer_head *bh = NULL;
123         ext4_fsblk_t bitmap_blk;
124         int err;
125 
126         desc = ext4_get_group_desc(sb, block_group, NULL);
127         if (!desc)
128                 return ERR_PTR(-EFSCORRUPTED);
129 
130         bitmap_blk = ext4_inode_bitmap(sb, desc);
131         if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
132             (bitmap_blk >= ext4_blocks_count(sbi->s_es))) {
133                 ext4_error(sb, "Invalid inode bitmap blk %llu in "
134                            "block_group %u", bitmap_blk, block_group);
135                 ext4_mark_group_bitmap_corrupted(sb, block_group,
136                                         EXT4_GROUP_INFO_IBITMAP_CORRUPT);
137                 return ERR_PTR(-EFSCORRUPTED);
138         }
139         bh = sb_getblk(sb, bitmap_blk);
140         if (unlikely(!bh)) {
141                 ext4_warning(sb, "Cannot read inode bitmap - "
142                              "block_group = %u, inode_bitmap = %llu",
143                              block_group, bitmap_blk);
144                 return ERR_PTR(-ENOMEM);
145         }
146         if (bitmap_uptodate(bh))
147                 goto verify;
148 
149         lock_buffer(bh);
150         if (bitmap_uptodate(bh)) {
151                 unlock_buffer(bh);
152                 goto verify;
153         }
154 
155         ext4_lock_group(sb, block_group);
156         if (ext4_has_group_desc_csum(sb) &&
157             (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT))) {
158                 if (block_group == 0) {
159                         ext4_unlock_group(sb, block_group);
160                         unlock_buffer(bh);
161                         ext4_error(sb, "Inode bitmap for bg 0 marked "
162                                    "uninitialized");
163                         err = -EFSCORRUPTED;
164                         goto out;
165                 }
166                 memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
167                 ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
168                                      sb->s_blocksize * 8, bh->b_data);
169                 set_bitmap_uptodate(bh);
170                 set_buffer_uptodate(bh);
171                 set_buffer_verified(bh);
172                 ext4_unlock_group(sb, block_group);
173                 unlock_buffer(bh);
174                 return bh;
175         }
176         ext4_unlock_group(sb, block_group);
177 
178         if (buffer_uptodate(bh)) {
179                 /*
180                  * if not uninit if bh is uptodate,
181                  * bitmap is also uptodate
182                  */
183                 set_bitmap_uptodate(bh);
184                 unlock_buffer(bh);
185                 goto verify;
186         }
187         /*
188          * submit the buffer_head for reading
189          */
190         trace_ext4_load_inode_bitmap(sb, block_group);
191         bh->b_end_io = ext4_end_bitmap_read;
192         get_bh(bh);
193         submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh);
194         wait_on_buffer(bh);
195         if (!buffer_uptodate(bh)) {
196                 put_bh(bh);
197                 ext4_error(sb, "Cannot read inode bitmap - "
198                            "block_group = %u, inode_bitmap = %llu",
199                            block_group, bitmap_blk);
200                 ext4_mark_group_bitmap_corrupted(sb, block_group,
201                                 EXT4_GROUP_INFO_IBITMAP_CORRUPT);
202                 return ERR_PTR(-EIO);
203         }
204 
205 verify:
206         err = ext4_validate_inode_bitmap(sb, desc, block_group, bh);
207         if (err)
208                 goto out;
209         return bh;
210 out:
211         put_bh(bh);
212         return ERR_PTR(err);
213 }
214 
215 /*
216  * NOTE! When we get the inode, we're the only people
217  * that have access to it, and as such there are no
218  * race conditions we have to worry about. The inode
219  * is not on the hash-lists, and it cannot be reached
220  * through the filesystem because the directory entry
221  * has been deleted earlier.
222  *
223  * HOWEVER: we must make sure that we get no aliases,
224  * which means that we have to call "clear_inode()"
225  * _before_ we mark the inode not in use in the inode
226  * bitmaps. Otherwise a newly created file might use
227  * the same inode number (not actually the same pointer
228  * though), and then we'd have two inodes sharing the
229  * same inode number and space on the harddisk.
230  */
231 void ext4_free_inode(handle_t *handle, struct inode *inode)
232 {
233         struct super_block *sb = inode->i_sb;
234         int is_directory;
235         unsigned long ino;
236         struct buffer_head *bitmap_bh = NULL;
237         struct buffer_head *bh2;
238         ext4_group_t block_group;
239         unsigned long bit;
240         struct ext4_group_desc *gdp;
241         struct ext4_super_block *es;
242         struct ext4_sb_info *sbi;
243         int fatal = 0, err, count, cleared;
244         struct ext4_group_info *grp;
245 
246         if (!sb) {
247                 printk(KERN_ERR "EXT4-fs: %s:%d: inode on "
248                        "nonexistent device\n", __func__, __LINE__);
249                 return;
250         }
251         if (atomic_read(&inode->i_count) > 1) {
252                 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: count=%d",
253                          __func__, __LINE__, inode->i_ino,
254                          atomic_read(&inode->i_count));
255                 return;
256         }
257         if (inode->i_nlink) {
258                 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: nlink=%d\n",
259                          __func__, __LINE__, inode->i_ino, inode->i_nlink);
260                 return;
261         }
262         sbi = EXT4_SB(sb);
263 
264         ino = inode->i_ino;
265         ext4_debug("freeing inode %lu\n", ino);
266         trace_ext4_free_inode(inode);
267 
268         /*
269          * Note: we must free any quota before locking the superblock,
270          * as writing the quota to disk may need the lock as well.
271          */
272         dquot_initialize(inode);
273         dquot_free_inode(inode);
274         dquot_drop(inode);
275 
276         is_directory = S_ISDIR(inode->i_mode);
277 
278         /* Do this BEFORE marking the inode not in use or returning an error */
279         ext4_clear_inode(inode);
280 
281         es = sbi->s_es;
282         if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
283                 ext4_error(sb, "reserved or nonexistent inode %lu", ino);
284                 goto error_return;
285         }
286         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
287         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
288         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
289         /* Don't bother if the inode bitmap is corrupt. */
290         grp = ext4_get_group_info(sb, block_group);
291         if (IS_ERR(bitmap_bh)) {
292                 fatal = PTR_ERR(bitmap_bh);
293                 bitmap_bh = NULL;
294                 goto error_return;
295         }
296         if (unlikely(EXT4_MB_GRP_IBITMAP_CORRUPT(grp))) {
297                 fatal = -EFSCORRUPTED;
298                 goto error_return;
299         }
300 
301         BUFFER_TRACE(bitmap_bh, "get_write_access");
302         fatal = ext4_journal_get_write_access(handle, bitmap_bh);
303         if (fatal)
304                 goto error_return;
305 
306         fatal = -ESRCH;
307         gdp = ext4_get_group_desc(sb, block_group, &bh2);
308         if (gdp) {
309                 BUFFER_TRACE(bh2, "get_write_access");
310                 fatal = ext4_journal_get_write_access(handle, bh2);
311         }
312         ext4_lock_group(sb, block_group);
313         cleared = ext4_test_and_clear_bit(bit, bitmap_bh->b_data);
314         if (fatal || !cleared) {
315                 ext4_unlock_group(sb, block_group);
316                 goto out;
317         }
318 
319         count = ext4_free_inodes_count(sb, gdp) + 1;
320         ext4_free_inodes_set(sb, gdp, count);
321         if (is_directory) {
322                 count = ext4_used_dirs_count(sb, gdp) - 1;
323                 ext4_used_dirs_set(sb, gdp, count);
324                 percpu_counter_dec(&sbi->s_dirs_counter);
325         }
326         ext4_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
327                                    EXT4_INODES_PER_GROUP(sb) / 8);
328         ext4_group_desc_csum_set(sb, block_group, gdp);
329         ext4_unlock_group(sb, block_group);
330 
331         percpu_counter_inc(&sbi->s_freeinodes_counter);
332         if (sbi->s_log_groups_per_flex) {
333                 ext4_group_t f = ext4_flex_group(sbi, block_group);
334 
335                 atomic_inc(&sbi->s_flex_groups[f].free_inodes);
336                 if (is_directory)
337                         atomic_dec(&sbi->s_flex_groups[f].used_dirs);
338         }
339         BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
340         fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);
341 out:
342         if (cleared) {
343                 BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
344                 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
345                 if (!fatal)
346                         fatal = err;
347         } else {
348                 ext4_error(sb, "bit already cleared for inode %lu", ino);
349                 ext4_mark_group_bitmap_corrupted(sb, block_group,
350                                         EXT4_GROUP_INFO_IBITMAP_CORRUPT);
351         }
352 
353 error_return:
354         brelse(bitmap_bh);
355         ext4_std_error(sb, fatal);
356 }
357 
358 struct orlov_stats {
359         __u64 free_clusters;
360         __u32 free_inodes;
361         __u32 used_dirs;
362 };
363 
364 /*
365  * Helper function for Orlov's allocator; returns critical information
366  * for a particular block group or flex_bg.  If flex_size is 1, then g
367  * is a block group number; otherwise it is flex_bg number.
368  */
369 static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
370                             int flex_size, struct orlov_stats *stats)
371 {
372         struct ext4_group_desc *desc;
373         struct flex_groups *flex_group = EXT4_SB(sb)->s_flex_groups;
374 
375         if (flex_size > 1) {
376                 stats->free_inodes = atomic_read(&flex_group[g].free_inodes);
377                 stats->free_clusters = atomic64_read(&flex_group[g].free_clusters);
378                 stats->used_dirs = atomic_read(&flex_group[g].used_dirs);
379                 return;
380         }
381 
382         desc = ext4_get_group_desc(sb, g, NULL);
383         if (desc) {
384                 stats->free_inodes = ext4_free_inodes_count(sb, desc);
385                 stats->free_clusters = ext4_free_group_clusters(sb, desc);
386                 stats->used_dirs = ext4_used_dirs_count(sb, desc);
387         } else {
388                 stats->free_inodes = 0;
389                 stats->free_clusters = 0;
390                 stats->used_dirs = 0;
391         }
392 }
393 
394 /*
395  * Orlov's allocator for directories.
396  *
397  * We always try to spread first-level directories.
398  *
399  * If there are blockgroups with both free inodes and free blocks counts
400  * not worse than average we return one with smallest directory count.
401  * Otherwise we simply return a random group.
402  *
403  * For the rest rules look so:
404  *
405  * It's OK to put directory into a group unless
406  * it has too many directories already (max_dirs) or
407  * it has too few free inodes left (min_inodes) or
408  * it has too few free blocks left (min_blocks) or
409  * Parent's group is preferred, if it doesn't satisfy these
410  * conditions we search cyclically through the rest. If none
411  * of the groups look good we just look for a group with more
412  * free inodes than average (starting at parent's group).
413  */
414 
415 static int find_group_orlov(struct super_block *sb, struct inode *parent,
416                             ext4_group_t *group, umode_t mode,
417                             const struct qstr *qstr)
418 {
419         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
420         struct ext4_sb_info *sbi = EXT4_SB(sb);
421         ext4_group_t real_ngroups = ext4_get_groups_count(sb);
422         int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
423         unsigned int freei, avefreei, grp_free;
424         ext4_fsblk_t freeb, avefreec;
425         unsigned int ndirs;
426         int max_dirs, min_inodes;
427         ext4_grpblk_t min_clusters;
428         ext4_group_t i, grp, g, ngroups;
429         struct ext4_group_desc *desc;
430         struct orlov_stats stats;
431         int flex_size = ext4_flex_bg_size(sbi);
432         struct dx_hash_info hinfo;
433 
434         ngroups = real_ngroups;
435         if (flex_size > 1) {
436                 ngroups = (real_ngroups + flex_size - 1) >>
437                         sbi->s_log_groups_per_flex;
438                 parent_group >>= sbi->s_log_groups_per_flex;
439         }
440 
441         freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
442         avefreei = freei / ngroups;
443         freeb = EXT4_C2B(sbi,
444                 percpu_counter_read_positive(&sbi->s_freeclusters_counter));
445         avefreec = freeb;
446         do_div(avefreec, ngroups);
447         ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
448 
449         if (S_ISDIR(mode) &&
450             ((parent == d_inode(sb->s_root)) ||
451              (ext4_test_inode_flag(parent, EXT4_INODE_TOPDIR)))) {
452                 int best_ndir = inodes_per_group;
453                 int ret = -1;
454 
455                 if (qstr) {
456                         hinfo.hash_version = DX_HASH_HALF_MD4;
457                         hinfo.seed = sbi->s_hash_seed;
458                         ext4fs_dirhash(qstr->name, qstr->len, &hinfo);
459                         grp = hinfo.hash;
460                 } else
461                         grp = prandom_u32();
462                 parent_group = (unsigned)grp % ngroups;
463                 for (i = 0; i < ngroups; i++) {
464                         g = (parent_group + i) % ngroups;
465                         get_orlov_stats(sb, g, flex_size, &stats);
466                         if (!stats.free_inodes)
467                                 continue;
468                         if (stats.used_dirs >= best_ndir)
469                                 continue;
470                         if (stats.free_inodes < avefreei)
471                                 continue;
472                         if (stats.free_clusters < avefreec)
473                                 continue;
474                         grp = g;
475                         ret = 0;
476                         best_ndir = stats.used_dirs;
477                 }
478                 if (ret)
479                         goto fallback;
480         found_flex_bg:
481                 if (flex_size == 1) {
482                         *group = grp;
483                         return 0;
484                 }
485 
486                 /*
487                  * We pack inodes at the beginning of the flexgroup's
488                  * inode tables.  Block allocation decisions will do
489                  * something similar, although regular files will
490                  * start at 2nd block group of the flexgroup.  See
491                  * ext4_ext_find_goal() and ext4_find_near().
492                  */
493                 grp *= flex_size;
494                 for (i = 0; i < flex_size; i++) {
495                         if (grp+i >= real_ngroups)
496                                 break;
497                         desc = ext4_get_group_desc(sb, grp+i, NULL);
498                         if (desc && ext4_free_inodes_count(sb, desc)) {
499                                 *group = grp+i;
500                                 return 0;
501                         }
502                 }
503                 goto fallback;
504         }
505 
506         max_dirs = ndirs / ngroups + inodes_per_group / 16;
507         min_inodes = avefreei - inodes_per_group*flex_size / 4;
508         if (min_inodes < 1)
509                 min_inodes = 1;
510         min_clusters = avefreec - EXT4_CLUSTERS_PER_GROUP(sb)*flex_size / 4;
511 
512         /*
513          * Start looking in the flex group where we last allocated an
514          * inode for this parent directory
515          */
516         if (EXT4_I(parent)->i_last_alloc_group != ~0) {
517                 parent_group = EXT4_I(parent)->i_last_alloc_group;
518                 if (flex_size > 1)
519                         parent_group >>= sbi->s_log_groups_per_flex;
520         }
521 
522         for (i = 0; i < ngroups; i++) {
523                 grp = (parent_group + i) % ngroups;
524                 get_orlov_stats(sb, grp, flex_size, &stats);
525                 if (stats.used_dirs >= max_dirs)
526                         continue;
527                 if (stats.free_inodes < min_inodes)
528                         continue;
529                 if (stats.free_clusters < min_clusters)
530                         continue;
531                 goto found_flex_bg;
532         }
533 
534 fallback:
535         ngroups = real_ngroups;
536         avefreei = freei / ngroups;
537 fallback_retry:
538         parent_group = EXT4_I(parent)->i_block_group;
539         for (i = 0; i < ngroups; i++) {
540                 grp = (parent_group + i) % ngroups;
541                 desc = ext4_get_group_desc(sb, grp, NULL);
542                 if (desc) {
543                         grp_free = ext4_free_inodes_count(sb, desc);
544                         if (grp_free && grp_free >= avefreei) {
545                                 *group = grp;
546                                 return 0;
547                         }
548                 }
549         }
550 
551         if (avefreei) {
552                 /*
553                  * The free-inodes counter is approximate, and for really small
554                  * filesystems the above test can fail to find any blockgroups
555                  */
556                 avefreei = 0;
557                 goto fallback_retry;
558         }
559 
560         return -1;
561 }
562 
563 static int find_group_other(struct super_block *sb, struct inode *parent,
564                             ext4_group_t *group, umode_t mode)
565 {
566         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
567         ext4_group_t i, last, ngroups = ext4_get_groups_count(sb);
568         struct ext4_group_desc *desc;
569         int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
570 
571         /*
572          * Try to place the inode is the same flex group as its
573          * parent.  If we can't find space, use the Orlov algorithm to
574          * find another flex group, and store that information in the
575          * parent directory's inode information so that use that flex
576          * group for future allocations.
577          */
578         if (flex_size > 1) {
579                 int retry = 0;
580 
581         try_again:
582                 parent_group &= ~(flex_size-1);
583                 last = parent_group + flex_size;
584                 if (last > ngroups)
585                         last = ngroups;
586                 for  (i = parent_group; i < last; i++) {
587                         desc = ext4_get_group_desc(sb, i, NULL);
588                         if (desc && ext4_free_inodes_count(sb, desc)) {
589                                 *group = i;
590                                 return 0;
591                         }
592                 }
593                 if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
594                         retry = 1;
595                         parent_group = EXT4_I(parent)->i_last_alloc_group;
596                         goto try_again;
597                 }
598                 /*
599                  * If this didn't work, use the Orlov search algorithm
600                  * to find a new flex group; we pass in the mode to
601                  * avoid the topdir algorithms.
602                  */
603                 *group = parent_group + flex_size;
604                 if (*group > ngroups)
605                         *group = 0;
606                 return find_group_orlov(sb, parent, group, mode, NULL);
607         }
608 
609         /*
610          * Try to place the inode in its parent directory
611          */
612         *group = parent_group;
613         desc = ext4_get_group_desc(sb, *group, NULL);
614         if (desc && ext4_free_inodes_count(sb, desc) &&
615             ext4_free_group_clusters(sb, desc))
616                 return 0;
617 
618         /*
619          * We're going to place this inode in a different blockgroup from its
620          * parent.  We want to cause files in a common directory to all land in
621          * the same blockgroup.  But we want files which are in a different
622          * directory which shares a blockgroup with our parent to land in a
623          * different blockgroup.
624          *
625          * So add our directory's i_ino into the starting point for the hash.
626          */
627         *group = (*group + parent->i_ino) % ngroups;
628 
629         /*
630          * Use a quadratic hash to find a group with a free inode and some free
631          * blocks.
632          */
633         for (i = 1; i < ngroups; i <<= 1) {
634                 *group += i;
635                 if (*group >= ngroups)
636                         *group -= ngroups;
637                 desc = ext4_get_group_desc(sb, *group, NULL);
638                 if (desc && ext4_free_inodes_count(sb, desc) &&
639                     ext4_free_group_clusters(sb, desc))
640                         return 0;
641         }
642 
643         /*
644          * That failed: try linear search for a free inode, even if that group
645          * has no free blocks.
646          */
647         *group = parent_group;
648         for (i = 0; i < ngroups; i++) {
649                 if (++*group >= ngroups)
650                         *group = 0;
651                 desc = ext4_get_group_desc(sb, *group, NULL);
652                 if (desc && ext4_free_inodes_count(sb, desc))
653                         return 0;
654         }
655 
656         return -1;
657 }
658 
659 /*
660  * In no journal mode, if an inode has recently been deleted, we want
661  * to avoid reusing it until we're reasonably sure the inode table
662  * block has been written back to disk.  (Yes, these values are
663  * somewhat arbitrary...)
664  */
665 #define RECENTCY_MIN    5
666 #define RECENTCY_DIRTY  300
667 
668 static int recently_deleted(struct super_block *sb, ext4_group_t group, int ino)
669 {
670         struct ext4_group_desc  *gdp;
671         struct ext4_inode       *raw_inode;
672         struct buffer_head      *bh;
673         int inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
674         int offset, ret = 0;
675         int recentcy = RECENTCY_MIN;
676         u32 dtime, now;
677 
678         gdp = ext4_get_group_desc(sb, group, NULL);
679         if (unlikely(!gdp))
680                 return 0;
681 
682         bh = sb_find_get_block(sb, ext4_inode_table(sb, gdp) +
683                        (ino / inodes_per_block));
684         if (!bh || !buffer_uptodate(bh))
685                 /*
686                  * If the block is not in the buffer cache, then it
687                  * must have been written out.
688                  */
689                 goto out;
690 
691         offset = (ino % inodes_per_block) * EXT4_INODE_SIZE(sb);
692         raw_inode = (struct ext4_inode *) (bh->b_data + offset);
693 
694         /* i_dtime is only 32 bits on disk, but we only care about relative
695          * times in the range of a few minutes (i.e. long enough to sync a
696          * recently-deleted inode to disk), so using the low 32 bits of the
697          * clock (a 68 year range) is enough, see time_before32() */
698         dtime = le32_to_cpu(raw_inode->i_dtime);
699         now = ktime_get_real_seconds();
700         if (buffer_dirty(bh))
701                 recentcy += RECENTCY_DIRTY;
702 
703         if (dtime && time_before32(dtime, now) &&
704             time_before32(now, dtime + recentcy))
705                 ret = 1;
706 out:
707         brelse(bh);
708         return ret;
709 }
710 
711 static int find_inode_bit(struct super_block *sb, ext4_group_t group,
712                           struct buffer_head *bitmap, unsigned long *ino)
713 {
714 next:
715         *ino = ext4_find_next_zero_bit((unsigned long *)
716                                        bitmap->b_data,
717                                        EXT4_INODES_PER_GROUP(sb), *ino);
718         if (*ino >= EXT4_INODES_PER_GROUP(sb))
719                 return 0;
720 
721         if ((EXT4_SB(sb)->s_journal == NULL) &&
722             recently_deleted(sb, group, *ino)) {
723                 *ino = *ino + 1;
724                 if (*ino < EXT4_INODES_PER_GROUP(sb))
725                         goto next;
726                 return 0;
727         }
728 
729         return 1;
730 }
731 
732 /*
733  * There are two policies for allocating an inode.  If the new inode is
734  * a directory, then a forward search is made for a block group with both
735  * free space and a low directory-to-inode ratio; if that fails, then of
736  * the groups with above-average free space, that group with the fewest
737  * directories already is chosen.
738  *
739  * For other inodes, search forward from the parent directory's block
740  * group to find a free inode.
741  */
742 struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
743                                umode_t mode, const struct qstr *qstr,
744                                __u32 goal, uid_t *owner, __u32 i_flags,
745                                int handle_type, unsigned int line_no,
746                                int nblocks)
747 {
748         struct super_block *sb;
749         struct buffer_head *inode_bitmap_bh = NULL;
750         struct buffer_head *group_desc_bh;
751         ext4_group_t ngroups, group = 0;
752         unsigned long ino = 0;
753         struct inode *inode;
754         struct ext4_group_desc *gdp = NULL;
755         struct ext4_inode_info *ei;
756         struct ext4_sb_info *sbi;
757         int ret2, err;
758         struct inode *ret;
759         ext4_group_t i;
760         ext4_group_t flex_group;
761         struct ext4_group_info *grp;
762         int encrypt = 0;
763 
764         /* Cannot create files in a deleted directory */
765         if (!dir || !dir->i_nlink)
766                 return ERR_PTR(-EPERM);
767 
768         sb = dir->i_sb;
769         sbi = EXT4_SB(sb);
770 
771         if (unlikely(ext4_forced_shutdown(sbi)))
772                 return ERR_PTR(-EIO);
773 
774         if ((ext4_encrypted_inode(dir) || DUMMY_ENCRYPTION_ENABLED(sbi)) &&
775             (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)) &&
776             !(i_flags & EXT4_EA_INODE_FL)) {
777                 err = fscrypt_get_encryption_info(dir);
778                 if (err)
779                         return ERR_PTR(err);
780                 if (!fscrypt_has_encryption_key(dir))
781                         return ERR_PTR(-ENOKEY);
782                 encrypt = 1;
783         }
784 
785         if (!handle && sbi->s_journal && !(i_flags & EXT4_EA_INODE_FL)) {
786 #ifdef CONFIG_EXT4_FS_POSIX_ACL
787                 struct posix_acl *p = get_acl(dir, ACL_TYPE_DEFAULT);
788 
789                 if (IS_ERR(p))
790                         return ERR_CAST(p);
791                 if (p) {
792                         int acl_size = p->a_count * sizeof(ext4_acl_entry);
793 
794                         nblocks += (S_ISDIR(mode) ? 2 : 1) *
795                                 __ext4_xattr_set_credits(sb, NULL /* inode */,
796                                         NULL /* block_bh */, acl_size,
797                                         true /* is_create */);
798                         posix_acl_release(p);
799                 }
800 #endif
801 
802 #ifdef CONFIG_SECURITY
803                 {
804                         int num_security_xattrs = 1;
805 
806 #ifdef CONFIG_INTEGRITY
807                         num_security_xattrs++;
808 #endif
809                         /*
810                          * We assume that security xattrs are never
811                          * more than 1k.  In practice they are under
812                          * 128 bytes.
813                          */
814                         nblocks += num_security_xattrs *
815                                 __ext4_xattr_set_credits(sb, NULL /* inode */,
816                                         NULL /* block_bh */, 1024,
817                                         true /* is_create */);
818                 }
819 #endif
820                 if (encrypt)
821                         nblocks += __ext4_xattr_set_credits(sb,
822                                         NULL /* inode */, NULL /* block_bh */,
823                                         FSCRYPT_SET_CONTEXT_MAX_SIZE,
824                                         true /* is_create */);
825         }
826 
827         ngroups = ext4_get_groups_count(sb);
828         trace_ext4_request_inode(dir, mode);
829         inode = new_inode(sb);
830         if (!inode)
831                 return ERR_PTR(-ENOMEM);
832         ei = EXT4_I(inode);
833 
834         /*
835          * Initialize owners and quota early so that we don't have to account
836          * for quota initialization worst case in standard inode creating
837          * transaction
838          */
839         if (owner) {
840                 inode->i_mode = mode;
841                 i_uid_write(inode, owner[0]);
842                 i_gid_write(inode, owner[1]);
843         } else if (test_opt(sb, GRPID)) {
844                 inode->i_mode = mode;
845                 inode->i_uid = current_fsuid();
846                 inode->i_gid = dir->i_gid;
847         } else
848                 inode_init_owner(inode, dir, mode);
849 
850         if (ext4_has_feature_project(sb) &&
851             ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT))
852                 ei->i_projid = EXT4_I(dir)->i_projid;
853         else
854                 ei->i_projid = make_kprojid(&init_user_ns, EXT4_DEF_PROJID);
855 
856         err = dquot_initialize(inode);
857         if (err)
858                 goto out;
859 
860         if (!goal)
861                 goal = sbi->s_inode_goal;
862 
863         if (goal && goal <= le32_to_cpu(sbi->s_es->s_inodes_count)) {
864                 group = (goal - 1) / EXT4_INODES_PER_GROUP(sb);
865                 ino = (goal - 1) % EXT4_INODES_PER_GROUP(sb);
866                 ret2 = 0;
867                 goto got_group;
868         }
869 
870         if (S_ISDIR(mode))
871                 ret2 = find_group_orlov(sb, dir, &group, mode, qstr);
872         else
873                 ret2 = find_group_other(sb, dir, &group, mode);
874 
875 got_group:
876         EXT4_I(dir)->i_last_alloc_group = group;
877         err = -ENOSPC;
878         if (ret2 == -1)
879                 goto out;
880 
881         /*
882          * Normally we will only go through one pass of this loop,
883          * unless we get unlucky and it turns out the group we selected
884          * had its last inode grabbed by someone else.
885          */
886         for (i = 0; i < ngroups; i++, ino = 0) {
887                 err = -EIO;
888 
889                 gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
890                 if (!gdp)
891                         goto out;
892 
893                 /*
894                  * Check free inodes count before loading bitmap.
895                  */
896                 if (ext4_free_inodes_count(sb, gdp) == 0)
897                         goto next_group;
898 
899                 grp = ext4_get_group_info(sb, group);
900                 /* Skip groups with already-known suspicious inode tables */
901                 if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
902                         goto next_group;
903 
904                 brelse(inode_bitmap_bh);
905                 inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
906                 /* Skip groups with suspicious inode tables */
907                 if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp) ||
908                     IS_ERR(inode_bitmap_bh)) {
909                         inode_bitmap_bh = NULL;
910                         goto next_group;
911                 }
912 
913 repeat_in_this_group:
914                 ret2 = find_inode_bit(sb, group, inode_bitmap_bh, &ino);
915                 if (!ret2)
916                         goto next_group;
917 
918                 if (group == 0 && (ino + 1) < EXT4_FIRST_INO(sb)) {
919                         ext4_error(sb, "reserved inode found cleared - "
920                                    "inode=%lu", ino + 1);
921                         ext4_mark_group_bitmap_corrupted(sb, group,
922                                         EXT4_GROUP_INFO_IBITMAP_CORRUPT);
923                         goto next_group;
924                 }
925 
926                 if (!handle) {
927                         BUG_ON(nblocks <= 0);
928                         handle = __ext4_journal_start_sb(dir->i_sb, line_no,
929                                                          handle_type, nblocks,
930                                                          0);
931                         if (IS_ERR(handle)) {
932                                 err = PTR_ERR(handle);
933                                 ext4_std_error(sb, err);
934                                 goto out;
935                         }
936                 }
937                 BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
938                 err = ext4_journal_get_write_access(handle, inode_bitmap_bh);
939                 if (err) {
940                         ext4_std_error(sb, err);
941                         goto out;
942                 }
943                 ext4_lock_group(sb, group);
944                 ret2 = ext4_test_and_set_bit(ino, inode_bitmap_bh->b_data);
945                 if (ret2) {
946                         /* Someone already took the bit. Repeat the search
947                          * with lock held.
948                          */
949                         ret2 = find_inode_bit(sb, group, inode_bitmap_bh, &ino);
950                         if (ret2) {
951                                 ext4_set_bit(ino, inode_bitmap_bh->b_data);
952                                 ret2 = 0;
953                         } else {
954                                 ret2 = 1; /* we didn't grab the inode */
955                         }
956                 }
957                 ext4_unlock_group(sb, group);
958                 ino++;          /* the inode bitmap is zero-based */
959                 if (!ret2)
960                         goto got; /* we grabbed the inode! */
961 
962                 if (ino < EXT4_INODES_PER_GROUP(sb))
963                         goto repeat_in_this_group;
964 next_group:
965                 if (++group == ngroups)
966                         group = 0;
967         }
968         err = -ENOSPC;
969         goto out;
970 
971 got:
972         BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata");
973         err = ext4_handle_dirty_metadata(handle, NULL, inode_bitmap_bh);
974         if (err) {
975                 ext4_std_error(sb, err);
976                 goto out;
977         }
978 
979         BUFFER_TRACE(group_desc_bh, "get_write_access");
980         err = ext4_journal_get_write_access(handle, group_desc_bh);
981         if (err) {
982                 ext4_std_error(sb, err);
983                 goto out;
984         }
985 
986         /* We may have to initialize the block bitmap if it isn't already */
987         if (ext4_has_group_desc_csum(sb) &&
988             gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
989                 struct buffer_head *block_bitmap_bh;
990 
991                 block_bitmap_bh = ext4_read_block_bitmap(sb, group);
992                 if (IS_ERR(block_bitmap_bh)) {
993                         err = PTR_ERR(block_bitmap_bh);
994                         goto out;
995                 }
996                 BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
997                 err = ext4_journal_get_write_access(handle, block_bitmap_bh);
998                 if (err) {
999                         brelse(block_bitmap_bh);
1000                         ext4_std_error(sb, err);
1001                         goto out;
1002                 }
1003 
1004                 BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
1005                 err = ext4_handle_dirty_metadata(handle, NULL, block_bitmap_bh);
1006 
1007                 /* recheck and clear flag under lock if we still need to */
1008                 ext4_lock_group(sb, group);
1009                 if (ext4_has_group_desc_csum(sb) &&
1010                     (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
1011                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
1012                         ext4_free_group_clusters_set(sb, gdp,
1013                                 ext4_free_clusters_after_init(sb, group, gdp));
1014                         ext4_block_bitmap_csum_set(sb, group, gdp,
1015                                                    block_bitmap_bh);
1016                         ext4_group_desc_csum_set(sb, group, gdp);
1017                 }
1018                 ext4_unlock_group(sb, group);
1019                 brelse(block_bitmap_bh);
1020 
1021                 if (err) {
1022                         ext4_std_error(sb, err);
1023                         goto out;
1024                 }
1025         }
1026 
1027         /* Update the relevant bg descriptor fields */
1028         if (ext4_has_group_desc_csum(sb)) {
1029                 int free;
1030                 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1031 
1032                 down_read(&grp->alloc_sem); /* protect vs itable lazyinit */
1033                 ext4_lock_group(sb, group); /* while we modify the bg desc */
1034                 free = EXT4_INODES_PER_GROUP(sb) -
1035                         ext4_itable_unused_count(sb, gdp);
1036                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
1037                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
1038                         free = 0;
1039                 }
1040                 /*
1041                  * Check the relative inode number against the last used
1042                  * relative inode number in this group. if it is greater
1043                  * we need to update the bg_itable_unused count
1044                  */
1045                 if (ino > free)
1046                         ext4_itable_unused_set(sb, gdp,
1047                                         (EXT4_INODES_PER_GROUP(sb) - ino));
1048                 up_read(&grp->alloc_sem);
1049         } else {
1050                 ext4_lock_group(sb, group);
1051         }
1052 
1053         ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1);
1054         if (S_ISDIR(mode)) {
1055                 ext4_used_dirs_set(sb, gdp, ext4_used_dirs_count(sb, gdp) + 1);
1056                 if (sbi->s_log_groups_per_flex) {
1057                         ext4_group_t f = ext4_flex_group(sbi, group);
1058 
1059                         atomic_inc(&sbi->s_flex_groups[f].used_dirs);
1060                 }
1061         }
1062         if (ext4_has_group_desc_csum(sb)) {
1063                 ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
1064                                            EXT4_INODES_PER_GROUP(sb) / 8);
1065                 ext4_group_desc_csum_set(sb, group, gdp);
1066         }
1067         ext4_unlock_group(sb, group);
1068 
1069         BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
1070         err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
1071         if (err) {
1072                 ext4_std_error(sb, err);
1073                 goto out;
1074         }
1075 
1076         percpu_counter_dec(&sbi->s_freeinodes_counter);
1077         if (S_ISDIR(mode))
1078                 percpu_counter_inc(&sbi->s_dirs_counter);
1079 
1080         if (sbi->s_log_groups_per_flex) {
1081                 flex_group = ext4_flex_group(sbi, group);
1082                 atomic_dec(&sbi->s_flex_groups[flex_group].free_inodes);
1083         }
1084 
1085         inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
1086         /* This is the optimal IO size (for stat), not the fs block size */
1087         inode->i_blocks = 0;
1088         inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
1089         ei->i_crtime = inode->i_mtime;
1090 
1091         memset(ei->i_data, 0, sizeof(ei->i_data));
1092         ei->i_dir_start_lookup = 0;
1093         ei->i_disksize = 0;
1094 
1095         /* Don't inherit extent flag from directory, amongst others. */
1096         ei->i_flags =
1097                 ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
1098         ei->i_flags |= i_flags;
1099         ei->i_file_acl = 0;
1100         ei->i_dtime = 0;
1101         ei->i_block_group = group;
1102         ei->i_last_alloc_group = ~0;
1103 
1104         ext4_set_inode_flags(inode);
1105         if (IS_DIRSYNC(inode))
1106                 ext4_handle_sync(handle);
1107         if (insert_inode_locked(inode) < 0) {
1108                 /*
1109                  * Likely a bitmap corruption causing inode to be allocated
1110                  * twice.
1111                  */
1112                 err = -EIO;
1113                 ext4_error(sb, "failed to insert inode %lu: doubly allocated?",
1114                            inode->i_ino);
1115                 ext4_mark_group_bitmap_corrupted(sb, group,
1116                                         EXT4_GROUP_INFO_IBITMAP_CORRUPT);
1117                 goto out;
1118         }
1119         inode->i_generation = prandom_u32();
1120 
1121         /* Precompute checksum seed for inode metadata */
1122         if (ext4_has_metadata_csum(sb)) {
1123                 __u32 csum;
1124                 __le32 inum = cpu_to_le32(inode->i_ino);
1125                 __le32 gen = cpu_to_le32(inode->i_generation);
1126                 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
1127                                    sizeof(inum));
1128                 ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
1129                                               sizeof(gen));
1130         }
1131 
1132         ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
1133         ext4_set_inode_state(inode, EXT4_STATE_NEW);
1134 
1135         ei->i_extra_isize = sbi->s_want_extra_isize;
1136         ei->i_inline_off = 0;
1137         if (ext4_has_feature_inline_data(sb))
1138                 ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
1139         ret = inode;
1140         err = dquot_alloc_inode(inode);
1141         if (err)
1142                 goto fail_drop;
1143 
1144         /*
1145          * Since the encryption xattr will always be unique, create it first so
1146          * that it's less likely to end up in an external xattr block and
1147          * prevent its deduplication.
1148          */
1149         if (encrypt) {
1150                 err = fscrypt_inherit_context(dir, inode, handle, true);
1151                 if (err)
1152                         goto fail_free_drop;
1153         }
1154 
1155         if (!(ei->i_flags & EXT4_EA_INODE_FL)) {
1156                 err = ext4_init_acl(handle, inode, dir);
1157                 if (err)
1158                         goto fail_free_drop;
1159 
1160                 err = ext4_init_security(handle, inode, dir, qstr);
1161                 if (err)
1162                         goto fail_free_drop;
1163         }
1164 
1165         if (ext4_has_feature_extents(sb)) {
1166                 /* set extent flag only for directory, file and normal symlink*/
1167                 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
1168                         ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
1169                         ext4_ext_tree_init(handle, inode);
1170                 }
1171         }
1172 
1173         if (ext4_handle_valid(handle)) {
1174                 ei->i_sync_tid = handle->h_transaction->t_tid;
1175                 ei->i_datasync_tid = handle->h_transaction->t_tid;
1176         }
1177 
1178         err = ext4_mark_inode_dirty(handle, inode);
1179         if (err) {
1180                 ext4_std_error(sb, err);
1181                 goto fail_free_drop;
1182         }
1183 
1184         ext4_debug("allocating inode %lu\n", inode->i_ino);
1185         trace_ext4_allocate_inode(inode, dir, mode);
1186         brelse(inode_bitmap_bh);
1187         return ret;
1188 
1189 fail_free_drop:
1190         dquot_free_inode(inode);
1191 fail_drop:
1192         clear_nlink(inode);
1193         unlock_new_inode(inode);
1194 out:
1195         dquot_drop(inode);
1196         inode->i_flags |= S_NOQUOTA;
1197         iput(inode);
1198         brelse(inode_bitmap_bh);
1199         return ERR_PTR(err);
1200 }
1201 
1202 /* Verify that we are loading a valid orphan from disk */
1203 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
1204 {
1205         unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
1206         ext4_group_t block_group;
1207         int bit;
1208         struct buffer_head *bitmap_bh = NULL;
1209         struct inode *inode = NULL;
1210         int err = -EFSCORRUPTED;
1211 
1212         if (ino < EXT4_FIRST_INO(sb) || ino > max_ino)
1213                 goto bad_orphan;
1214 
1215         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
1216         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
1217         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
1218         if (IS_ERR(bitmap_bh))
1219                 return ERR_CAST(bitmap_bh);
1220 
1221         /* Having the inode bit set should be a 100% indicator that this
1222          * is a valid orphan (no e2fsck run on fs).  Orphans also include
1223          * inodes that were being truncated, so we can't check i_nlink==0.
1224          */
1225         if (!ext4_test_bit(bit, bitmap_bh->b_data))
1226                 goto bad_orphan;
1227 
1228         inode = ext4_iget(sb, ino, EXT4_IGET_NORMAL);
1229         if (IS_ERR(inode)) {
1230                 err = PTR_ERR(inode);
1231                 ext4_error(sb, "couldn't read orphan inode %lu (err %d)",
1232                            ino, err);
1233                 return inode;
1234         }
1235 
1236         /*
1237          * If the orphans has i_nlinks > 0 then it should be able to
1238          * be truncated, otherwise it won't be removed from the orphan
1239          * list during processing and an infinite loop will result.
1240          * Similarly, it must not be a bad inode.
1241          */
1242         if ((inode->i_nlink && !ext4_can_truncate(inode)) ||
1243             is_bad_inode(inode))
1244                 goto bad_orphan;
1245 
1246         if (NEXT_ORPHAN(inode) > max_ino)
1247                 goto bad_orphan;
1248         brelse(bitmap_bh);
1249         return inode;
1250 
1251 bad_orphan:
1252         ext4_error(sb, "bad orphan inode %lu", ino);
1253         if (bitmap_bh)
1254                 printk(KERN_ERR "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1255                        bit, (unsigned long long)bitmap_bh->b_blocknr,
1256                        ext4_test_bit(bit, bitmap_bh->b_data));
1257         if (inode) {
1258                 printk(KERN_ERR "is_bad_inode(inode)=%d\n",
1259                        is_bad_inode(inode));
1260                 printk(KERN_ERR "NEXT_ORPHAN(inode)=%u\n",
1261                        NEXT_ORPHAN(inode));
1262                 printk(KERN_ERR "max_ino=%lu\n", max_ino);
1263                 printk(KERN_ERR "i_nlink=%u\n", inode->i_nlink);
1264                 /* Avoid freeing blocks if we got a bad deleted inode */
1265                 if (inode->i_nlink == 0)
1266                         inode->i_blocks = 0;
1267                 iput(inode);
1268         }
1269         brelse(bitmap_bh);
1270         return ERR_PTR(err);
1271 }
1272 
1273 unsigned long ext4_count_free_inodes(struct super_block *sb)
1274 {
1275         unsigned long desc_count;
1276         struct ext4_group_desc *gdp;
1277         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1278 #ifdef EXT4FS_DEBUG
1279         struct ext4_super_block *es;
1280         unsigned long bitmap_count, x;
1281         struct buffer_head *bitmap_bh = NULL;
1282 
1283         es = EXT4_SB(sb)->s_es;
1284         desc_count = 0;
1285         bitmap_count = 0;
1286         gdp = NULL;
1287         for (i = 0; i < ngroups; i++) {
1288                 gdp = ext4_get_group_desc(sb, i, NULL);
1289                 if (!gdp)
1290                         continue;
1291                 desc_count += ext4_free_inodes_count(sb, gdp);
1292                 brelse(bitmap_bh);
1293                 bitmap_bh = ext4_read_inode_bitmap(sb, i);
1294                 if (IS_ERR(bitmap_bh)) {
1295                         bitmap_bh = NULL;
1296                         continue;
1297                 }
1298 
1299                 x = ext4_count_free(bitmap_bh->b_data,
1300                                     EXT4_INODES_PER_GROUP(sb) / 8);
1301                 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1302                         (unsigned long) i, ext4_free_inodes_count(sb, gdp), x);
1303                 bitmap_count += x;
1304         }
1305         brelse(bitmap_bh);
1306         printk(KERN_DEBUG "ext4_count_free_inodes: "
1307                "stored = %u, computed = %lu, %lu\n",
1308                le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1309         return desc_count;
1310 #else
1311         desc_count = 0;
1312         for (i = 0; i < ngroups; i++) {
1313                 gdp = ext4_get_group_desc(sb, i, NULL);
1314                 if (!gdp)
1315                         continue;
1316                 desc_count += ext4_free_inodes_count(sb, gdp);
1317                 cond_resched();
1318         }
1319         return desc_count;
1320 #endif
1321 }
1322 
1323 /* Called at mount-time, super-block is locked */
1324 unsigned long ext4_count_dirs(struct super_block * sb)
1325 {
1326         unsigned long count = 0;
1327         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1328 
1329         for (i = 0; i < ngroups; i++) {
1330                 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1331                 if (!gdp)
1332                         continue;
1333                 count += ext4_used_dirs_count(sb, gdp);
1334         }
1335         return count;
1336 }
1337 
1338 /*
1339  * Zeroes not yet zeroed inode table - just write zeroes through the whole
1340  * inode table. Must be called without any spinlock held. The only place
1341  * where it is called from on active part of filesystem is ext4lazyinit
1342  * thread, so we do not need any special locks, however we have to prevent
1343  * inode allocation from the current group, so we take alloc_sem lock, to
1344  * block ext4_new_inode() until we are finished.
1345  */
1346 int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
1347                                  int barrier)
1348 {
1349         struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1350         struct ext4_sb_info *sbi = EXT4_SB(sb);
1351         struct ext4_group_desc *gdp = NULL;
1352         struct buffer_head *group_desc_bh;
1353         handle_t *handle;
1354         ext4_fsblk_t blk;
1355         int num, ret = 0, used_blks = 0;
1356 
1357         /* This should not happen, but just to be sure check this */
1358         if (sb_rdonly(sb)) {
1359                 ret = 1;
1360                 goto out;
1361         }
1362 
1363         gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
1364         if (!gdp)
1365                 goto out;
1366 
1367         /*
1368          * We do not need to lock this, because we are the only one
1369          * handling this flag.
1370          */
1371         if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED))
1372                 goto out;
1373 
1374         handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
1375         if (IS_ERR(handle)) {
1376                 ret = PTR_ERR(handle);
1377                 goto out;
1378         }
1379 
1380         down_write(&grp->alloc_sem);
1381         /*
1382          * If inode bitmap was already initialized there may be some
1383          * used inodes so we need to skip blocks with used inodes in
1384          * inode table.
1385          */
1386         if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)))
1387                 used_blks = DIV_ROUND_UP((EXT4_INODES_PER_GROUP(sb) -
1388                             ext4_itable_unused_count(sb, gdp)),
1389                             sbi->s_inodes_per_block);
1390 
1391         if ((used_blks < 0) || (used_blks > sbi->s_itb_per_group) ||
1392             ((group == 0) && ((EXT4_INODES_PER_GROUP(sb) -
1393                                ext4_itable_unused_count(sb, gdp)) <
1394                               EXT4_FIRST_INO(sb)))) {
1395                 ext4_error(sb, "Something is wrong with group %u: "
1396                            "used itable blocks: %d; "
1397                            "itable unused count: %u",
1398                            group, used_blks,
1399                            ext4_itable_unused_count(sb, gdp));
1400                 ret = 1;
1401                 goto err_out;
1402         }
1403 
1404         blk = ext4_inode_table(sb, gdp) + used_blks;
1405         num = sbi->s_itb_per_group - used_blks;
1406 
1407         BUFFER_TRACE(group_desc_bh, "get_write_access");
1408         ret = ext4_journal_get_write_access(handle,
1409                                             group_desc_bh);
1410         if (ret)
1411                 goto err_out;
1412 
1413         /*
1414          * Skip zeroout if the inode table is full. But we set the ZEROED
1415          * flag anyway, because obviously, when it is full it does not need
1416          * further zeroing.
1417          */
1418         if (unlikely(num == 0))
1419                 goto skip_zeroout;
1420 
1421         ext4_debug("going to zero out inode table in group %d\n",
1422                    group);
1423         ret = sb_issue_zeroout(sb, blk, num, GFP_NOFS);
1424         if (ret < 0)
1425                 goto err_out;
1426         if (barrier)
1427                 blkdev_issue_flush(sb->s_bdev, GFP_NOFS, NULL);
1428 
1429 skip_zeroout:
1430         ext4_lock_group(sb, group);
1431         gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);
1432         ext4_group_desc_csum_set(sb, group, gdp);
1433         ext4_unlock_group(sb, group);
1434 
1435         BUFFER_TRACE(group_desc_bh,
1436                      "call ext4_handle_dirty_metadata");
1437         ret = ext4_handle_dirty_metadata(handle, NULL,
1438                                          group_desc_bh);
1439 
1440 err_out:
1441         up_write(&grp->alloc_sem);
1442         ext4_journal_stop(handle);
1443 out:
1444         return ret;
1445 }
1446 

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