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Linux/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 
 27 #include "ext4.h"
 28 #include "ext4_jbd2.h"
 29 #include "xattr.h"
 30 #include "acl.h"
 31 
 32 #include <trace/events/ext4.h>
 33 
 34 /*
 35  * ialloc.c contains the inodes allocation and deallocation routines
 36  */
 37 
 38 /*
 39  * The free inodes are managed by bitmaps.  A file system contains several
 40  * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
 41  * block for inodes, N blocks for the inode table and data blocks.
 42  *
 43  * The file system contains group descriptors which are located after the
 44  * super block.  Each descriptor contains the number of the bitmap block and
 45  * the free blocks count in the block.
 46  */
 47 
 48 /*
 49  * To avoid calling the atomic setbit hundreds or thousands of times, we only
 50  * need to use it within a single byte (to ensure we get endianness right).
 51  * We can use memset for the rest of the bitmap as there are no other users.
 52  */
 53 void ext4_mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
 54 {
 55         int i;
 56 
 57         if (start_bit >= end_bit)
 58                 return;
 59 
 60         ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
 61         for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
 62                 ext4_set_bit(i, bitmap);
 63         if (i < end_bit)
 64                 memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
 65 }
 66 
 67 /* Initializes an uninitialized inode bitmap */
 68 static unsigned ext4_init_inode_bitmap(struct super_block *sb,
 69                                        struct buffer_head *bh,
 70                                        ext4_group_t block_group,
 71                                        struct ext4_group_desc *gdp)
 72 {
 73         J_ASSERT_BH(bh, buffer_locked(bh));
 74 
 75         /* If checksum is bad mark all blocks and inodes use to prevent
 76          * allocation, essentially implementing a per-group read-only flag. */
 77         if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
 78                 ext4_error(sb, "Checksum bad for group %u", block_group);
 79                 ext4_free_group_clusters_set(sb, gdp, 0);
 80                 ext4_free_inodes_set(sb, gdp, 0);
 81                 ext4_itable_unused_set(sb, gdp, 0);
 82                 memset(bh->b_data, 0xff, sb->s_blocksize);
 83                 ext4_inode_bitmap_csum_set(sb, block_group, gdp, bh,
 84                                            EXT4_INODES_PER_GROUP(sb) / 8);
 85                 return 0;
 86         }
 87 
 88         memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
 89         ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb), sb->s_blocksize * 8,
 90                         bh->b_data);
 91         ext4_inode_bitmap_csum_set(sb, block_group, gdp, bh,
 92                                    EXT4_INODES_PER_GROUP(sb) / 8);
 93         ext4_group_desc_csum_set(sb, block_group, gdp);
 94 
 95         return EXT4_INODES_PER_GROUP(sb);
 96 }
 97 
 98 void ext4_end_bitmap_read(struct buffer_head *bh, int uptodate)
 99 {
100         if (uptodate) {
101                 set_buffer_uptodate(bh);
102                 set_bitmap_uptodate(bh);
103         }
104         unlock_buffer(bh);
105         put_bh(bh);
106 }
107 
108 /*
109  * Read the inode allocation bitmap for a given block_group, reading
110  * into the specified slot in the superblock's bitmap cache.
111  *
112  * Return buffer_head of bitmap on success or NULL.
113  */
114 static struct buffer_head *
115 ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
116 {
117         struct ext4_group_desc *desc;
118         struct buffer_head *bh = NULL;
119         ext4_fsblk_t bitmap_blk;
120 
121         desc = ext4_get_group_desc(sb, block_group, NULL);
122         if (!desc)
123                 return NULL;
124 
125         bitmap_blk = ext4_inode_bitmap(sb, desc);
126         bh = sb_getblk(sb, bitmap_blk);
127         if (unlikely(!bh)) {
128                 ext4_error(sb, "Cannot read inode bitmap - "
129                             "block_group = %u, inode_bitmap = %llu",
130                             block_group, bitmap_blk);
131                 return NULL;
132         }
133         if (bitmap_uptodate(bh))
134                 goto verify;
135 
136         lock_buffer(bh);
137         if (bitmap_uptodate(bh)) {
138                 unlock_buffer(bh);
139                 goto verify;
140         }
141 
142         ext4_lock_group(sb, block_group);
143         if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
144                 ext4_init_inode_bitmap(sb, bh, block_group, desc);
145                 set_bitmap_uptodate(bh);
146                 set_buffer_uptodate(bh);
147                 set_buffer_verified(bh);
148                 ext4_unlock_group(sb, block_group);
149                 unlock_buffer(bh);
150                 return bh;
151         }
152         ext4_unlock_group(sb, block_group);
153 
154         if (buffer_uptodate(bh)) {
155                 /*
156                  * if not uninit if bh is uptodate,
157                  * bitmap is also uptodate
158                  */
159                 set_bitmap_uptodate(bh);
160                 unlock_buffer(bh);
161                 goto verify;
162         }
163         /*
164          * submit the buffer_head for reading
165          */
166         trace_ext4_load_inode_bitmap(sb, block_group);
167         bh->b_end_io = ext4_end_bitmap_read;
168         get_bh(bh);
169         submit_bh(READ, bh);
170         wait_on_buffer(bh);
171         if (!buffer_uptodate(bh)) {
172                 put_bh(bh);
173                 ext4_error(sb, "Cannot read inode bitmap - "
174                            "block_group = %u, inode_bitmap = %llu",
175                            block_group, bitmap_blk);
176                 return NULL;
177         }
178 
179 verify:
180         ext4_lock_group(sb, block_group);
181         if (!buffer_verified(bh) &&
182             !ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh,
183                                            EXT4_INODES_PER_GROUP(sb) / 8)) {
184                 ext4_unlock_group(sb, block_group);
185                 put_bh(bh);
186                 ext4_error(sb, "Corrupt inode bitmap - block_group = %u, "
187                            "inode_bitmap = %llu", block_group, bitmap_blk);
188                 return NULL;
189         }
190         ext4_unlock_group(sb, block_group);
191         set_buffer_verified(bh);
192         return bh;
193 }
194 
195 /*
196  * NOTE! When we get the inode, we're the only people
197  * that have access to it, and as such there are no
198  * race conditions we have to worry about. The inode
199  * is not on the hash-lists, and it cannot be reached
200  * through the filesystem because the directory entry
201  * has been deleted earlier.
202  *
203  * HOWEVER: we must make sure that we get no aliases,
204  * which means that we have to call "clear_inode()"
205  * _before_ we mark the inode not in use in the inode
206  * bitmaps. Otherwise a newly created file might use
207  * the same inode number (not actually the same pointer
208  * though), and then we'd have two inodes sharing the
209  * same inode number and space on the harddisk.
210  */
211 void ext4_free_inode(handle_t *handle, struct inode *inode)
212 {
213         struct super_block *sb = inode->i_sb;
214         int is_directory;
215         unsigned long ino;
216         struct buffer_head *bitmap_bh = NULL;
217         struct buffer_head *bh2;
218         ext4_group_t block_group;
219         unsigned long bit;
220         struct ext4_group_desc *gdp;
221         struct ext4_super_block *es;
222         struct ext4_sb_info *sbi;
223         int fatal = 0, err, count, cleared;
224 
225         if (!sb) {
226                 printk(KERN_ERR "EXT4-fs: %s:%d: inode on "
227                        "nonexistent device\n", __func__, __LINE__);
228                 return;
229         }
230         if (atomic_read(&inode->i_count) > 1) {
231                 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: count=%d",
232                          __func__, __LINE__, inode->i_ino,
233                          atomic_read(&inode->i_count));
234                 return;
235         }
236         if (inode->i_nlink) {
237                 ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: nlink=%d\n",
238                          __func__, __LINE__, inode->i_ino, inode->i_nlink);
239                 return;
240         }
241         sbi = EXT4_SB(sb);
242 
243         ino = inode->i_ino;
244         ext4_debug("freeing inode %lu\n", ino);
245         trace_ext4_free_inode(inode);
246 
247         /*
248          * Note: we must free any quota before locking the superblock,
249          * as writing the quota to disk may need the lock as well.
250          */
251         dquot_initialize(inode);
252         ext4_xattr_delete_inode(handle, inode);
253         dquot_free_inode(inode);
254         dquot_drop(inode);
255 
256         is_directory = S_ISDIR(inode->i_mode);
257 
258         /* Do this BEFORE marking the inode not in use or returning an error */
259         ext4_clear_inode(inode);
260 
261         es = EXT4_SB(sb)->s_es;
262         if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
263                 ext4_error(sb, "reserved or nonexistent inode %lu", ino);
264                 goto error_return;
265         }
266         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
267         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
268         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
269         if (!bitmap_bh)
270                 goto error_return;
271 
272         BUFFER_TRACE(bitmap_bh, "get_write_access");
273         fatal = ext4_journal_get_write_access(handle, bitmap_bh);
274         if (fatal)
275                 goto error_return;
276 
277         fatal = -ESRCH;
278         gdp = ext4_get_group_desc(sb, block_group, &bh2);
279         if (gdp) {
280                 BUFFER_TRACE(bh2, "get_write_access");
281                 fatal = ext4_journal_get_write_access(handle, bh2);
282         }
283         ext4_lock_group(sb, block_group);
284         cleared = ext4_test_and_clear_bit(bit, bitmap_bh->b_data);
285         if (fatal || !cleared) {
286                 ext4_unlock_group(sb, block_group);
287                 goto out;
288         }
289 
290         count = ext4_free_inodes_count(sb, gdp) + 1;
291         ext4_free_inodes_set(sb, gdp, count);
292         if (is_directory) {
293                 count = ext4_used_dirs_count(sb, gdp) - 1;
294                 ext4_used_dirs_set(sb, gdp, count);
295                 percpu_counter_dec(&sbi->s_dirs_counter);
296         }
297         ext4_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
298                                    EXT4_INODES_PER_GROUP(sb) / 8);
299         ext4_group_desc_csum_set(sb, block_group, gdp);
300         ext4_unlock_group(sb, block_group);
301 
302         percpu_counter_inc(&sbi->s_freeinodes_counter);
303         if (sbi->s_log_groups_per_flex) {
304                 ext4_group_t f = ext4_flex_group(sbi, block_group);
305 
306                 atomic_inc(&sbi->s_flex_groups[f].free_inodes);
307                 if (is_directory)
308                         atomic_dec(&sbi->s_flex_groups[f].used_dirs);
309         }
310         BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
311         fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);
312 out:
313         if (cleared) {
314                 BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
315                 err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
316                 if (!fatal)
317                         fatal = err;
318         } else
319                 ext4_error(sb, "bit already cleared for inode %lu", ino);
320 
321 error_return:
322         brelse(bitmap_bh);
323         ext4_std_error(sb, fatal);
324 }
325 
326 struct orlov_stats {
327         __u32 free_inodes;
328         __u32 free_clusters;
329         __u32 used_dirs;
330 };
331 
332 /*
333  * Helper function for Orlov's allocator; returns critical information
334  * for a particular block group or flex_bg.  If flex_size is 1, then g
335  * is a block group number; otherwise it is flex_bg number.
336  */
337 static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
338                             int flex_size, struct orlov_stats *stats)
339 {
340         struct ext4_group_desc *desc;
341         struct flex_groups *flex_group = EXT4_SB(sb)->s_flex_groups;
342 
343         if (flex_size > 1) {
344                 stats->free_inodes = atomic_read(&flex_group[g].free_inodes);
345                 stats->free_clusters = atomic_read(&flex_group[g].free_clusters);
346                 stats->used_dirs = atomic_read(&flex_group[g].used_dirs);
347                 return;
348         }
349 
350         desc = ext4_get_group_desc(sb, g, NULL);
351         if (desc) {
352                 stats->free_inodes = ext4_free_inodes_count(sb, desc);
353                 stats->free_clusters = ext4_free_group_clusters(sb, desc);
354                 stats->used_dirs = ext4_used_dirs_count(sb, desc);
355         } else {
356                 stats->free_inodes = 0;
357                 stats->free_clusters = 0;
358                 stats->used_dirs = 0;
359         }
360 }
361 
362 /*
363  * Orlov's allocator for directories.
364  *
365  * We always try to spread first-level directories.
366  *
367  * If there are blockgroups with both free inodes and free blocks counts
368  * not worse than average we return one with smallest directory count.
369  * Otherwise we simply return a random group.
370  *
371  * For the rest rules look so:
372  *
373  * It's OK to put directory into a group unless
374  * it has too many directories already (max_dirs) or
375  * it has too few free inodes left (min_inodes) or
376  * it has too few free blocks left (min_blocks) or
377  * Parent's group is preferred, if it doesn't satisfy these
378  * conditions we search cyclically through the rest. If none
379  * of the groups look good we just look for a group with more
380  * free inodes than average (starting at parent's group).
381  */
382 
383 static int find_group_orlov(struct super_block *sb, struct inode *parent,
384                             ext4_group_t *group, umode_t mode,
385                             const struct qstr *qstr)
386 {
387         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
388         struct ext4_sb_info *sbi = EXT4_SB(sb);
389         ext4_group_t real_ngroups = ext4_get_groups_count(sb);
390         int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
391         unsigned int freei, avefreei, grp_free;
392         ext4_fsblk_t freeb, avefreec;
393         unsigned int ndirs;
394         int max_dirs, min_inodes;
395         ext4_grpblk_t min_clusters;
396         ext4_group_t i, grp, g, ngroups;
397         struct ext4_group_desc *desc;
398         struct orlov_stats stats;
399         int flex_size = ext4_flex_bg_size(sbi);
400         struct dx_hash_info hinfo;
401 
402         ngroups = real_ngroups;
403         if (flex_size > 1) {
404                 ngroups = (real_ngroups + flex_size - 1) >>
405                         sbi->s_log_groups_per_flex;
406                 parent_group >>= sbi->s_log_groups_per_flex;
407         }
408 
409         freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
410         avefreei = freei / ngroups;
411         freeb = EXT4_C2B(sbi,
412                 percpu_counter_read_positive(&sbi->s_freeclusters_counter));
413         avefreec = freeb;
414         do_div(avefreec, ngroups);
415         ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
416 
417         if (S_ISDIR(mode) &&
418             ((parent == sb->s_root->d_inode) ||
419              (ext4_test_inode_flag(parent, EXT4_INODE_TOPDIR)))) {
420                 int best_ndir = inodes_per_group;
421                 int ret = -1;
422 
423                 if (qstr) {
424                         hinfo.hash_version = DX_HASH_HALF_MD4;
425                         hinfo.seed = sbi->s_hash_seed;
426                         ext4fs_dirhash(qstr->name, qstr->len, &hinfo);
427                         grp = hinfo.hash;
428                 } else
429                         get_random_bytes(&grp, sizeof(grp));
430                 parent_group = (unsigned)grp % ngroups;
431                 for (i = 0; i < ngroups; i++) {
432                         g = (parent_group + i) % ngroups;
433                         get_orlov_stats(sb, g, flex_size, &stats);
434                         if (!stats.free_inodes)
435                                 continue;
436                         if (stats.used_dirs >= best_ndir)
437                                 continue;
438                         if (stats.free_inodes < avefreei)
439                                 continue;
440                         if (stats.free_clusters < avefreec)
441                                 continue;
442                         grp = g;
443                         ret = 0;
444                         best_ndir = stats.used_dirs;
445                 }
446                 if (ret)
447                         goto fallback;
448         found_flex_bg:
449                 if (flex_size == 1) {
450                         *group = grp;
451                         return 0;
452                 }
453 
454                 /*
455                  * We pack inodes at the beginning of the flexgroup's
456                  * inode tables.  Block allocation decisions will do
457                  * something similar, although regular files will
458                  * start at 2nd block group of the flexgroup.  See
459                  * ext4_ext_find_goal() and ext4_find_near().
460                  */
461                 grp *= flex_size;
462                 for (i = 0; i < flex_size; i++) {
463                         if (grp+i >= real_ngroups)
464                                 break;
465                         desc = ext4_get_group_desc(sb, grp+i, NULL);
466                         if (desc && ext4_free_inodes_count(sb, desc)) {
467                                 *group = grp+i;
468                                 return 0;
469                         }
470                 }
471                 goto fallback;
472         }
473 
474         max_dirs = ndirs / ngroups + inodes_per_group / 16;
475         min_inodes = avefreei - inodes_per_group*flex_size / 4;
476         if (min_inodes < 1)
477                 min_inodes = 1;
478         min_clusters = avefreec - EXT4_CLUSTERS_PER_GROUP(sb)*flex_size / 4;
479 
480         /*
481          * Start looking in the flex group where we last allocated an
482          * inode for this parent directory
483          */
484         if (EXT4_I(parent)->i_last_alloc_group != ~0) {
485                 parent_group = EXT4_I(parent)->i_last_alloc_group;
486                 if (flex_size > 1)
487                         parent_group >>= sbi->s_log_groups_per_flex;
488         }
489 
490         for (i = 0; i < ngroups; i++) {
491                 grp = (parent_group + i) % ngroups;
492                 get_orlov_stats(sb, grp, flex_size, &stats);
493                 if (stats.used_dirs >= max_dirs)
494                         continue;
495                 if (stats.free_inodes < min_inodes)
496                         continue;
497                 if (stats.free_clusters < min_clusters)
498                         continue;
499                 goto found_flex_bg;
500         }
501 
502 fallback:
503         ngroups = real_ngroups;
504         avefreei = freei / ngroups;
505 fallback_retry:
506         parent_group = EXT4_I(parent)->i_block_group;
507         for (i = 0; i < ngroups; i++) {
508                 grp = (parent_group + i) % ngroups;
509                 desc = ext4_get_group_desc(sb, grp, NULL);
510                 if (desc) {
511                         grp_free = ext4_free_inodes_count(sb, desc);
512                         if (grp_free && grp_free >= avefreei) {
513                                 *group = grp;
514                                 return 0;
515                         }
516                 }
517         }
518 
519         if (avefreei) {
520                 /*
521                  * The free-inodes counter is approximate, and for really small
522                  * filesystems the above test can fail to find any blockgroups
523                  */
524                 avefreei = 0;
525                 goto fallback_retry;
526         }
527 
528         return -1;
529 }
530 
531 static int find_group_other(struct super_block *sb, struct inode *parent,
532                             ext4_group_t *group, umode_t mode)
533 {
534         ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
535         ext4_group_t i, last, ngroups = ext4_get_groups_count(sb);
536         struct ext4_group_desc *desc;
537         int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
538 
539         /*
540          * Try to place the inode is the same flex group as its
541          * parent.  If we can't find space, use the Orlov algorithm to
542          * find another flex group, and store that information in the
543          * parent directory's inode information so that use that flex
544          * group for future allocations.
545          */
546         if (flex_size > 1) {
547                 int retry = 0;
548 
549         try_again:
550                 parent_group &= ~(flex_size-1);
551                 last = parent_group + flex_size;
552                 if (last > ngroups)
553                         last = ngroups;
554                 for  (i = parent_group; i < last; i++) {
555                         desc = ext4_get_group_desc(sb, i, NULL);
556                         if (desc && ext4_free_inodes_count(sb, desc)) {
557                                 *group = i;
558                                 return 0;
559                         }
560                 }
561                 if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
562                         retry = 1;
563                         parent_group = EXT4_I(parent)->i_last_alloc_group;
564                         goto try_again;
565                 }
566                 /*
567                  * If this didn't work, use the Orlov search algorithm
568                  * to find a new flex group; we pass in the mode to
569                  * avoid the topdir algorithms.
570                  */
571                 *group = parent_group + flex_size;
572                 if (*group > ngroups)
573                         *group = 0;
574                 return find_group_orlov(sb, parent, group, mode, NULL);
575         }
576 
577         /*
578          * Try to place the inode in its parent directory
579          */
580         *group = parent_group;
581         desc = ext4_get_group_desc(sb, *group, NULL);
582         if (desc && ext4_free_inodes_count(sb, desc) &&
583             ext4_free_group_clusters(sb, desc))
584                 return 0;
585 
586         /*
587          * We're going to place this inode in a different blockgroup from its
588          * parent.  We want to cause files in a common directory to all land in
589          * the same blockgroup.  But we want files which are in a different
590          * directory which shares a blockgroup with our parent to land in a
591          * different blockgroup.
592          *
593          * So add our directory's i_ino into the starting point for the hash.
594          */
595         *group = (*group + parent->i_ino) % ngroups;
596 
597         /*
598          * Use a quadratic hash to find a group with a free inode and some free
599          * blocks.
600          */
601         for (i = 1; i < ngroups; i <<= 1) {
602                 *group += i;
603                 if (*group >= ngroups)
604                         *group -= ngroups;
605                 desc = ext4_get_group_desc(sb, *group, NULL);
606                 if (desc && ext4_free_inodes_count(sb, desc) &&
607                     ext4_free_group_clusters(sb, desc))
608                         return 0;
609         }
610 
611         /*
612          * That failed: try linear search for a free inode, even if that group
613          * has no free blocks.
614          */
615         *group = parent_group;
616         for (i = 0; i < ngroups; i++) {
617                 if (++*group >= ngroups)
618                         *group = 0;
619                 desc = ext4_get_group_desc(sb, *group, NULL);
620                 if (desc && ext4_free_inodes_count(sb, desc))
621                         return 0;
622         }
623 
624         return -1;
625 }
626 
627 /*
628  * There are two policies for allocating an inode.  If the new inode is
629  * a directory, then a forward search is made for a block group with both
630  * free space and a low directory-to-inode ratio; if that fails, then of
631  * the groups with above-average free space, that group with the fewest
632  * directories already is chosen.
633  *
634  * For other inodes, search forward from the parent directory's block
635  * group to find a free inode.
636  */
637 struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, umode_t mode,
638                              const struct qstr *qstr, __u32 goal, uid_t *owner)
639 {
640         struct super_block *sb;
641         struct buffer_head *inode_bitmap_bh = NULL;
642         struct buffer_head *group_desc_bh;
643         ext4_group_t ngroups, group = 0;
644         unsigned long ino = 0;
645         struct inode *inode;
646         struct ext4_group_desc *gdp = NULL;
647         struct ext4_inode_info *ei;
648         struct ext4_sb_info *sbi;
649         int ret2, err = 0;
650         struct inode *ret;
651         ext4_group_t i;
652         ext4_group_t flex_group;
653 
654         /* Cannot create files in a deleted directory */
655         if (!dir || !dir->i_nlink)
656                 return ERR_PTR(-EPERM);
657 
658         sb = dir->i_sb;
659         ngroups = ext4_get_groups_count(sb);
660         trace_ext4_request_inode(dir, mode);
661         inode = new_inode(sb);
662         if (!inode)
663                 return ERR_PTR(-ENOMEM);
664         ei = EXT4_I(inode);
665         sbi = EXT4_SB(sb);
666 
667         if (!goal)
668                 goal = sbi->s_inode_goal;
669 
670         if (goal && goal <= le32_to_cpu(sbi->s_es->s_inodes_count)) {
671                 group = (goal - 1) / EXT4_INODES_PER_GROUP(sb);
672                 ino = (goal - 1) % EXT4_INODES_PER_GROUP(sb);
673                 ret2 = 0;
674                 goto got_group;
675         }
676 
677         if (S_ISDIR(mode))
678                 ret2 = find_group_orlov(sb, dir, &group, mode, qstr);
679         else
680                 ret2 = find_group_other(sb, dir, &group, mode);
681 
682 got_group:
683         EXT4_I(dir)->i_last_alloc_group = group;
684         err = -ENOSPC;
685         if (ret2 == -1)
686                 goto out;
687 
688         /*
689          * Normally we will only go through one pass of this loop,
690          * unless we get unlucky and it turns out the group we selected
691          * had its last inode grabbed by someone else.
692          */
693         for (i = 0; i < ngroups; i++, ino = 0) {
694                 err = -EIO;
695 
696                 gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
697                 if (!gdp)
698                         goto fail;
699 
700                 /*
701                  * Check free inodes count before loading bitmap.
702                  */
703                 if (ext4_free_inodes_count(sb, gdp) == 0) {
704                         if (++group == ngroups)
705                                 group = 0;
706                         continue;
707                 }
708 
709                 brelse(inode_bitmap_bh);
710                 inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
711                 if (!inode_bitmap_bh)
712                         goto fail;
713 
714 repeat_in_this_group:
715                 ino = ext4_find_next_zero_bit((unsigned long *)
716                                               inode_bitmap_bh->b_data,
717                                               EXT4_INODES_PER_GROUP(sb), ino);
718                 if (ino >= EXT4_INODES_PER_GROUP(sb)) {
719                         if (++group == ngroups)
720                                 group = 0;
721                         continue;
722                 }
723                 if (group == 0 && (ino+1) < EXT4_FIRST_INO(sb)) {
724                         ext4_error(sb, "reserved inode found cleared - "
725                                    "inode=%lu", ino + 1);
726                         continue;
727                 }
728                 BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
729                 err = ext4_journal_get_write_access(handle, inode_bitmap_bh);
730                 if (err)
731                         goto fail;
732                 ext4_lock_group(sb, group);
733                 ret2 = ext4_test_and_set_bit(ino, inode_bitmap_bh->b_data);
734                 ext4_unlock_group(sb, group);
735                 ino++;          /* the inode bitmap is zero-based */
736                 if (!ret2)
737                         goto got; /* we grabbed the inode! */
738                 if (ino < EXT4_INODES_PER_GROUP(sb))
739                         goto repeat_in_this_group;
740         }
741         err = -ENOSPC;
742         goto out;
743 
744 got:
745         BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata");
746         err = ext4_handle_dirty_metadata(handle, NULL, inode_bitmap_bh);
747         if (err)
748                 goto fail;
749 
750         /* We may have to initialize the block bitmap if it isn't already */
751         if (ext4_has_group_desc_csum(sb) &&
752             gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
753                 struct buffer_head *block_bitmap_bh;
754 
755                 block_bitmap_bh = ext4_read_block_bitmap(sb, group);
756                 BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
757                 err = ext4_journal_get_write_access(handle, block_bitmap_bh);
758                 if (err) {
759                         brelse(block_bitmap_bh);
760                         goto fail;
761                 }
762 
763                 BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
764                 err = ext4_handle_dirty_metadata(handle, NULL, block_bitmap_bh);
765 
766                 /* recheck and clear flag under lock if we still need to */
767                 ext4_lock_group(sb, group);
768                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
769                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
770                         ext4_free_group_clusters_set(sb, gdp,
771                                 ext4_free_clusters_after_init(sb, group, gdp));
772                         ext4_block_bitmap_csum_set(sb, group, gdp,
773                                                    block_bitmap_bh);
774                         ext4_group_desc_csum_set(sb, group, gdp);
775                 }
776                 ext4_unlock_group(sb, group);
777                 brelse(block_bitmap_bh);
778 
779                 if (err)
780                         goto fail;
781         }
782 
783         BUFFER_TRACE(group_desc_bh, "get_write_access");
784         err = ext4_journal_get_write_access(handle, group_desc_bh);
785         if (err)
786                 goto fail;
787 
788         /* Update the relevant bg descriptor fields */
789         if (ext4_has_group_desc_csum(sb)) {
790                 int free;
791                 struct ext4_group_info *grp = ext4_get_group_info(sb, group);
792 
793                 down_read(&grp->alloc_sem); /* protect vs itable lazyinit */
794                 ext4_lock_group(sb, group); /* while we modify the bg desc */
795                 free = EXT4_INODES_PER_GROUP(sb) -
796                         ext4_itable_unused_count(sb, gdp);
797                 if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
798                         gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
799                         free = 0;
800                 }
801                 /*
802                  * Check the relative inode number against the last used
803                  * relative inode number in this group. if it is greater
804                  * we need to update the bg_itable_unused count
805                  */
806                 if (ino > free)
807                         ext4_itable_unused_set(sb, gdp,
808                                         (EXT4_INODES_PER_GROUP(sb) - ino));
809                 up_read(&grp->alloc_sem);
810         } else {
811                 ext4_lock_group(sb, group);
812         }
813 
814         ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1);
815         if (S_ISDIR(mode)) {
816                 ext4_used_dirs_set(sb, gdp, ext4_used_dirs_count(sb, gdp) + 1);
817                 if (sbi->s_log_groups_per_flex) {
818                         ext4_group_t f = ext4_flex_group(sbi, group);
819 
820                         atomic_inc(&sbi->s_flex_groups[f].used_dirs);
821                 }
822         }
823         if (ext4_has_group_desc_csum(sb)) {
824                 ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
825                                            EXT4_INODES_PER_GROUP(sb) / 8);
826                 ext4_group_desc_csum_set(sb, group, gdp);
827         }
828         ext4_unlock_group(sb, group);
829 
830         BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
831         err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
832         if (err)
833                 goto fail;
834 
835         percpu_counter_dec(&sbi->s_freeinodes_counter);
836         if (S_ISDIR(mode))
837                 percpu_counter_inc(&sbi->s_dirs_counter);
838 
839         if (sbi->s_log_groups_per_flex) {
840                 flex_group = ext4_flex_group(sbi, group);
841                 atomic_dec(&sbi->s_flex_groups[flex_group].free_inodes);
842         }
843         if (owner) {
844                 inode->i_mode = mode;
845                 i_uid_write(inode, owner[0]);
846                 i_gid_write(inode, owner[1]);
847         } else if (test_opt(sb, GRPID)) {
848                 inode->i_mode = mode;
849                 inode->i_uid = current_fsuid();
850                 inode->i_gid = dir->i_gid;
851         } else
852                 inode_init_owner(inode, dir, mode);
853 
854         inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
855         /* This is the optimal IO size (for stat), not the fs block size */
856         inode->i_blocks = 0;
857         inode->i_mtime = inode->i_atime = inode->i_ctime = ei->i_crtime =
858                                                        ext4_current_time(inode);
859 
860         memset(ei->i_data, 0, sizeof(ei->i_data));
861         ei->i_dir_start_lookup = 0;
862         ei->i_disksize = 0;
863 
864         /* Don't inherit extent flag from directory, amongst others. */
865         ei->i_flags =
866                 ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
867         ei->i_file_acl = 0;
868         ei->i_dtime = 0;
869         ei->i_block_group = group;
870         ei->i_last_alloc_group = ~0;
871 
872         ext4_set_inode_flags(inode);
873         if (IS_DIRSYNC(inode))
874                 ext4_handle_sync(handle);
875         if (insert_inode_locked(inode) < 0) {
876                 /*
877                  * Likely a bitmap corruption causing inode to be allocated
878                  * twice.
879                  */
880                 err = -EIO;
881                 goto fail;
882         }
883         spin_lock(&sbi->s_next_gen_lock);
884         inode->i_generation = sbi->s_next_generation++;
885         spin_unlock(&sbi->s_next_gen_lock);
886 
887         /* Precompute checksum seed for inode metadata */
888         if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
889                         EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
890                 __u32 csum;
891                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
892                 __le32 inum = cpu_to_le32(inode->i_ino);
893                 __le32 gen = cpu_to_le32(inode->i_generation);
894                 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
895                                    sizeof(inum));
896                 ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
897                                               sizeof(gen));
898         }
899 
900         ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
901         ext4_set_inode_state(inode, EXT4_STATE_NEW);
902 
903         ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;
904 
905         ei->i_inline_off = 0;
906         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_INLINE_DATA))
907                 ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
908 
909         ret = inode;
910         dquot_initialize(inode);
911         err = dquot_alloc_inode(inode);
912         if (err)
913                 goto fail_drop;
914 
915         err = ext4_init_acl(handle, inode, dir);
916         if (err)
917                 goto fail_free_drop;
918 
919         err = ext4_init_security(handle, inode, dir, qstr);
920         if (err)
921                 goto fail_free_drop;
922 
923         if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS)) {
924                 /* set extent flag only for directory, file and normal symlink*/
925                 if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
926                         ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
927                         ext4_ext_tree_init(handle, inode);
928                 }
929         }
930 
931         if (ext4_handle_valid(handle)) {
932                 ei->i_sync_tid = handle->h_transaction->t_tid;
933                 ei->i_datasync_tid = handle->h_transaction->t_tid;
934         }
935 
936         err = ext4_mark_inode_dirty(handle, inode);
937         if (err) {
938                 ext4_std_error(sb, err);
939                 goto fail_free_drop;
940         }
941 
942         ext4_debug("allocating inode %lu\n", inode->i_ino);
943         trace_ext4_allocate_inode(inode, dir, mode);
944         goto really_out;
945 fail:
946         ext4_std_error(sb, err);
947 out:
948         iput(inode);
949         ret = ERR_PTR(err);
950 really_out:
951         brelse(inode_bitmap_bh);
952         return ret;
953 
954 fail_free_drop:
955         dquot_free_inode(inode);
956 
957 fail_drop:
958         dquot_drop(inode);
959         inode->i_flags |= S_NOQUOTA;
960         clear_nlink(inode);
961         unlock_new_inode(inode);
962         iput(inode);
963         brelse(inode_bitmap_bh);
964         return ERR_PTR(err);
965 }
966 
967 /* Verify that we are loading a valid orphan from disk */
968 struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
969 {
970         unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
971         ext4_group_t block_group;
972         int bit;
973         struct buffer_head *bitmap_bh;
974         struct inode *inode = NULL;
975         long err = -EIO;
976 
977         /* Error cases - e2fsck has already cleaned up for us */
978         if (ino > max_ino) {
979                 ext4_warning(sb, "bad orphan ino %lu!  e2fsck was run?", ino);
980                 goto error;
981         }
982 
983         block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
984         bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
985         bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
986         if (!bitmap_bh) {
987                 ext4_warning(sb, "inode bitmap error for orphan %lu", ino);
988                 goto error;
989         }
990 
991         /* Having the inode bit set should be a 100% indicator that this
992          * is a valid orphan (no e2fsck run on fs).  Orphans also include
993          * inodes that were being truncated, so we can't check i_nlink==0.
994          */
995         if (!ext4_test_bit(bit, bitmap_bh->b_data))
996                 goto bad_orphan;
997 
998         inode = ext4_iget(sb, ino);
999         if (IS_ERR(inode))
1000                 goto iget_failed;
1001 
1002         /*
1003          * If the orphans has i_nlinks > 0 then it should be able to be
1004          * truncated, otherwise it won't be removed from the orphan list
1005          * during processing and an infinite loop will result.
1006          */
1007         if (inode->i_nlink && !ext4_can_truncate(inode))
1008                 goto bad_orphan;
1009 
1010         if (NEXT_ORPHAN(inode) > max_ino)
1011                 goto bad_orphan;
1012         brelse(bitmap_bh);
1013         return inode;
1014 
1015 iget_failed:
1016         err = PTR_ERR(inode);
1017         inode = NULL;
1018 bad_orphan:
1019         ext4_warning(sb, "bad orphan inode %lu!  e2fsck was run?", ino);
1020         printk(KERN_NOTICE "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1021                bit, (unsigned long long)bitmap_bh->b_blocknr,
1022                ext4_test_bit(bit, bitmap_bh->b_data));
1023         printk(KERN_NOTICE "inode=%p\n", inode);
1024         if (inode) {
1025                 printk(KERN_NOTICE "is_bad_inode(inode)=%d\n",
1026                        is_bad_inode(inode));
1027                 printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
1028                        NEXT_ORPHAN(inode));
1029                 printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
1030                 printk(KERN_NOTICE "i_nlink=%u\n", inode->i_nlink);
1031                 /* Avoid freeing blocks if we got a bad deleted inode */
1032                 if (inode->i_nlink == 0)
1033                         inode->i_blocks = 0;
1034                 iput(inode);
1035         }
1036         brelse(bitmap_bh);
1037 error:
1038         return ERR_PTR(err);
1039 }
1040 
1041 unsigned long ext4_count_free_inodes(struct super_block *sb)
1042 {
1043         unsigned long desc_count;
1044         struct ext4_group_desc *gdp;
1045         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1046 #ifdef EXT4FS_DEBUG
1047         struct ext4_super_block *es;
1048         unsigned long bitmap_count, x;
1049         struct buffer_head *bitmap_bh = NULL;
1050 
1051         es = EXT4_SB(sb)->s_es;
1052         desc_count = 0;
1053         bitmap_count = 0;
1054         gdp = NULL;
1055         for (i = 0; i < ngroups; i++) {
1056                 gdp = ext4_get_group_desc(sb, i, NULL);
1057                 if (!gdp)
1058                         continue;
1059                 desc_count += ext4_free_inodes_count(sb, gdp);
1060                 brelse(bitmap_bh);
1061                 bitmap_bh = ext4_read_inode_bitmap(sb, i);
1062                 if (!bitmap_bh)
1063                         continue;
1064 
1065                 x = ext4_count_free(bitmap_bh->b_data,
1066                                     EXT4_INODES_PER_GROUP(sb) / 8);
1067                 printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1068                         (unsigned long) i, ext4_free_inodes_count(sb, gdp), x);
1069                 bitmap_count += x;
1070         }
1071         brelse(bitmap_bh);
1072         printk(KERN_DEBUG "ext4_count_free_inodes: "
1073                "stored = %u, computed = %lu, %lu\n",
1074                le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1075         return desc_count;
1076 #else
1077         desc_count = 0;
1078         for (i = 0; i < ngroups; i++) {
1079                 gdp = ext4_get_group_desc(sb, i, NULL);
1080                 if (!gdp)
1081                         continue;
1082                 desc_count += ext4_free_inodes_count(sb, gdp);
1083                 cond_resched();
1084         }
1085         return desc_count;
1086 #endif
1087 }
1088 
1089 /* Called at mount-time, super-block is locked */
1090 unsigned long ext4_count_dirs(struct super_block * sb)
1091 {
1092         unsigned long count = 0;
1093         ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1094 
1095         for (i = 0; i < ngroups; i++) {
1096                 struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1097                 if (!gdp)
1098                         continue;
1099                 count += ext4_used_dirs_count(sb, gdp);
1100         }
1101         return count;
1102 }
1103 
1104 /*
1105  * Zeroes not yet zeroed inode table - just write zeroes through the whole
1106  * inode table. Must be called without any spinlock held. The only place
1107  * where it is called from on active part of filesystem is ext4lazyinit
1108  * thread, so we do not need any special locks, however we have to prevent
1109  * inode allocation from the current group, so we take alloc_sem lock, to
1110  * block ext4_new_inode() until we are finished.
1111  */
1112 int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
1113                                  int barrier)
1114 {
1115         struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1116         struct ext4_sb_info *sbi = EXT4_SB(sb);
1117         struct ext4_group_desc *gdp = NULL;
1118         struct buffer_head *group_desc_bh;
1119         handle_t *handle;
1120         ext4_fsblk_t blk;
1121         int num, ret = 0, used_blks = 0;
1122 
1123         /* This should not happen, but just to be sure check this */
1124         if (sb->s_flags & MS_RDONLY) {
1125                 ret = 1;
1126                 goto out;
1127         }
1128 
1129         gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
1130         if (!gdp)
1131                 goto out;
1132 
1133         /*
1134          * We do not need to lock this, because we are the only one
1135          * handling this flag.
1136          */
1137         if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED))
1138                 goto out;
1139 
1140         handle = ext4_journal_start_sb(sb, 1);
1141         if (IS_ERR(handle)) {
1142                 ret = PTR_ERR(handle);
1143                 goto out;
1144         }
1145 
1146         down_write(&grp->alloc_sem);
1147         /*
1148          * If inode bitmap was already initialized there may be some
1149          * used inodes so we need to skip blocks with used inodes in
1150          * inode table.
1151          */
1152         if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)))
1153                 used_blks = DIV_ROUND_UP((EXT4_INODES_PER_GROUP(sb) -
1154                             ext4_itable_unused_count(sb, gdp)),
1155                             sbi->s_inodes_per_block);
1156 
1157         if ((used_blks < 0) || (used_blks > sbi->s_itb_per_group)) {
1158                 ext4_error(sb, "Something is wrong with group %u: "
1159                            "used itable blocks: %d; "
1160                            "itable unused count: %u",
1161                            group, used_blks,
1162                            ext4_itable_unused_count(sb, gdp));
1163                 ret = 1;
1164                 goto err_out;
1165         }
1166 
1167         blk = ext4_inode_table(sb, gdp) + used_blks;
1168         num = sbi->s_itb_per_group - used_blks;
1169 
1170         BUFFER_TRACE(group_desc_bh, "get_write_access");
1171         ret = ext4_journal_get_write_access(handle,
1172                                             group_desc_bh);
1173         if (ret)
1174                 goto err_out;
1175 
1176         /*
1177          * Skip zeroout if the inode table is full. But we set the ZEROED
1178          * flag anyway, because obviously, when it is full it does not need
1179          * further zeroing.
1180          */
1181         if (unlikely(num == 0))
1182                 goto skip_zeroout;
1183 
1184         ext4_debug("going to zero out inode table in group %d\n",
1185                    group);
1186         ret = sb_issue_zeroout(sb, blk, num, GFP_NOFS);
1187         if (ret < 0)
1188                 goto err_out;
1189         if (barrier)
1190                 blkdev_issue_flush(sb->s_bdev, GFP_NOFS, NULL);
1191 
1192 skip_zeroout:
1193         ext4_lock_group(sb, group);
1194         gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);
1195         ext4_group_desc_csum_set(sb, group, gdp);
1196         ext4_unlock_group(sb, group);
1197 
1198         BUFFER_TRACE(group_desc_bh,
1199                      "call ext4_handle_dirty_metadata");
1200         ret = ext4_handle_dirty_metadata(handle, NULL,
1201                                          group_desc_bh);
1202 
1203 err_out:
1204         up_write(&grp->alloc_sem);
1205         ext4_journal_stop(handle);
1206 out:
1207         return ret;
1208 }
1209 

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