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TOMOYO Linux Cross Reference
Linux/fs/ext2/super.c

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  1 /*
  2  *  linux/fs/ext2/super.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  *  from
 10  *
 11  *  linux/fs/minix/inode.c
 12  *
 13  *  Copyright (C) 1991, 1992  Linus Torvalds
 14  *
 15  *  Big-endian to little-endian byte-swapping/bitmaps by
 16  *        David S. Miller (davem@caip.rutgers.edu), 1995
 17  */
 18 
 19 #include <linux/module.h>
 20 #include <linux/string.h>
 21 #include <linux/fs.h>
 22 #include <linux/slab.h>
 23 #include <linux/init.h>
 24 #include <linux/blkdev.h>
 25 #include <linux/parser.h>
 26 #include <linux/random.h>
 27 #include <linux/buffer_head.h>
 28 #include <linux/exportfs.h>
 29 #include <linux/vfs.h>
 30 #include <linux/seq_file.h>
 31 #include <linux/mount.h>
 32 #include <linux/log2.h>
 33 #include <linux/quotaops.h>
 34 #include <asm/uaccess.h>
 35 #include "ext2.h"
 36 #include "xattr.h"
 37 #include "acl.h"
 38 
 39 static void ext2_sync_super(struct super_block *sb,
 40                             struct ext2_super_block *es, int wait);
 41 static int ext2_remount (struct super_block * sb, int * flags, char * data);
 42 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
 43 static int ext2_sync_fs(struct super_block *sb, int wait);
 44 static int ext2_freeze(struct super_block *sb);
 45 static int ext2_unfreeze(struct super_block *sb);
 46 
 47 void ext2_error(struct super_block *sb, const char *function,
 48                 const char *fmt, ...)
 49 {
 50         struct va_format vaf;
 51         va_list args;
 52         struct ext2_sb_info *sbi = EXT2_SB(sb);
 53         struct ext2_super_block *es = sbi->s_es;
 54 
 55         if (!(sb->s_flags & MS_RDONLY)) {
 56                 spin_lock(&sbi->s_lock);
 57                 sbi->s_mount_state |= EXT2_ERROR_FS;
 58                 es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
 59                 spin_unlock(&sbi->s_lock);
 60                 ext2_sync_super(sb, es, 1);
 61         }
 62 
 63         va_start(args, fmt);
 64 
 65         vaf.fmt = fmt;
 66         vaf.va = &args;
 67 
 68         printk(KERN_CRIT "EXT2-fs (%s): error: %s: %pV\n",
 69                sb->s_id, function, &vaf);
 70 
 71         va_end(args);
 72 
 73         if (test_opt(sb, ERRORS_PANIC))
 74                 panic("EXT2-fs: panic from previous error\n");
 75         if (test_opt(sb, ERRORS_RO)) {
 76                 ext2_msg(sb, KERN_CRIT,
 77                              "error: remounting filesystem read-only");
 78                 sb->s_flags |= MS_RDONLY;
 79         }
 80 }
 81 
 82 void ext2_msg(struct super_block *sb, const char *prefix,
 83                 const char *fmt, ...)
 84 {
 85         struct va_format vaf;
 86         va_list args;
 87 
 88         va_start(args, fmt);
 89 
 90         vaf.fmt = fmt;
 91         vaf.va = &args;
 92 
 93         printk("%sEXT2-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
 94 
 95         va_end(args);
 96 }
 97 
 98 /*
 99  * This must be called with sbi->s_lock held.
100  */
101 void ext2_update_dynamic_rev(struct super_block *sb)
102 {
103         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
104 
105         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
106                 return;
107 
108         ext2_msg(sb, KERN_WARNING,
109                      "warning: updating to rev %d because of "
110                      "new feature flag, running e2fsck is recommended",
111                      EXT2_DYNAMIC_REV);
112 
113         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
114         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
115         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
116         /* leave es->s_feature_*compat flags alone */
117         /* es->s_uuid will be set by e2fsck if empty */
118 
119         /*
120          * The rest of the superblock fields should be zero, and if not it
121          * means they are likely already in use, so leave them alone.  We
122          * can leave it up to e2fsck to clean up any inconsistencies there.
123          */
124 }
125 
126 static void ext2_put_super (struct super_block * sb)
127 {
128         int db_count;
129         int i;
130         struct ext2_sb_info *sbi = EXT2_SB(sb);
131 
132         dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
133 
134         ext2_xattr_put_super(sb);
135         if (!(sb->s_flags & MS_RDONLY)) {
136                 struct ext2_super_block *es = sbi->s_es;
137 
138                 spin_lock(&sbi->s_lock);
139                 es->s_state = cpu_to_le16(sbi->s_mount_state);
140                 spin_unlock(&sbi->s_lock);
141                 ext2_sync_super(sb, es, 1);
142         }
143         db_count = sbi->s_gdb_count;
144         for (i = 0; i < db_count; i++)
145                 if (sbi->s_group_desc[i])
146                         brelse (sbi->s_group_desc[i]);
147         kfree(sbi->s_group_desc);
148         kfree(sbi->s_debts);
149         percpu_counter_destroy(&sbi->s_freeblocks_counter);
150         percpu_counter_destroy(&sbi->s_freeinodes_counter);
151         percpu_counter_destroy(&sbi->s_dirs_counter);
152         brelse (sbi->s_sbh);
153         sb->s_fs_info = NULL;
154         kfree(sbi->s_blockgroup_lock);
155         kfree(sbi);
156 }
157 
158 static struct kmem_cache * ext2_inode_cachep;
159 
160 static struct inode *ext2_alloc_inode(struct super_block *sb)
161 {
162         struct ext2_inode_info *ei;
163         ei = kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
164         if (!ei)
165                 return NULL;
166         ei->i_block_alloc_info = NULL;
167         ei->vfs_inode.i_version = 1;
168 #ifdef CONFIG_QUOTA
169         memset(&ei->i_dquot, 0, sizeof(ei->i_dquot));
170 #endif
171 
172         return &ei->vfs_inode;
173 }
174 
175 static void ext2_i_callback(struct rcu_head *head)
176 {
177         struct inode *inode = container_of(head, struct inode, i_rcu);
178         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
179 }
180 
181 static void ext2_destroy_inode(struct inode *inode)
182 {
183         call_rcu(&inode->i_rcu, ext2_i_callback);
184 }
185 
186 static void init_once(void *foo)
187 {
188         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
189 
190         rwlock_init(&ei->i_meta_lock);
191 #ifdef CONFIG_EXT2_FS_XATTR
192         init_rwsem(&ei->xattr_sem);
193 #endif
194         mutex_init(&ei->truncate_mutex);
195         inode_init_once(&ei->vfs_inode);
196 }
197 
198 static int __init init_inodecache(void)
199 {
200         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
201                                              sizeof(struct ext2_inode_info),
202                                              0, (SLAB_RECLAIM_ACCOUNT|
203                                                 SLAB_MEM_SPREAD),
204                                              init_once);
205         if (ext2_inode_cachep == NULL)
206                 return -ENOMEM;
207         return 0;
208 }
209 
210 static void destroy_inodecache(void)
211 {
212         /*
213          * Make sure all delayed rcu free inodes are flushed before we
214          * destroy cache.
215          */
216         rcu_barrier();
217         kmem_cache_destroy(ext2_inode_cachep);
218 }
219 
220 static int ext2_show_options(struct seq_file *seq, struct dentry *root)
221 {
222         struct super_block *sb = root->d_sb;
223         struct ext2_sb_info *sbi = EXT2_SB(sb);
224         struct ext2_super_block *es = sbi->s_es;
225         unsigned long def_mount_opts;
226 
227         spin_lock(&sbi->s_lock);
228         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
229 
230         if (sbi->s_sb_block != 1)
231                 seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
232         if (test_opt(sb, MINIX_DF))
233                 seq_puts(seq, ",minixdf");
234         if (test_opt(sb, GRPID))
235                 seq_puts(seq, ",grpid");
236         if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
237                 seq_puts(seq, ",nogrpid");
238         if (!uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT2_DEF_RESUID)) ||
239             le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
240                 seq_printf(seq, ",resuid=%u",
241                                 from_kuid_munged(&init_user_ns, sbi->s_resuid));
242         }
243         if (!gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT2_DEF_RESGID)) ||
244             le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
245                 seq_printf(seq, ",resgid=%u",
246                                 from_kgid_munged(&init_user_ns, sbi->s_resgid));
247         }
248         if (test_opt(sb, ERRORS_RO)) {
249                 int def_errors = le16_to_cpu(es->s_errors);
250 
251                 if (def_errors == EXT2_ERRORS_PANIC ||
252                     def_errors == EXT2_ERRORS_CONTINUE) {
253                         seq_puts(seq, ",errors=remount-ro");
254                 }
255         }
256         if (test_opt(sb, ERRORS_CONT))
257                 seq_puts(seq, ",errors=continue");
258         if (test_opt(sb, ERRORS_PANIC))
259                 seq_puts(seq, ",errors=panic");
260         if (test_opt(sb, NO_UID32))
261                 seq_puts(seq, ",nouid32");
262         if (test_opt(sb, DEBUG))
263                 seq_puts(seq, ",debug");
264         if (test_opt(sb, OLDALLOC))
265                 seq_puts(seq, ",oldalloc");
266 
267 #ifdef CONFIG_EXT2_FS_XATTR
268         if (test_opt(sb, XATTR_USER))
269                 seq_puts(seq, ",user_xattr");
270         if (!test_opt(sb, XATTR_USER) &&
271             (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
272                 seq_puts(seq, ",nouser_xattr");
273         }
274 #endif
275 
276 #ifdef CONFIG_EXT2_FS_POSIX_ACL
277         if (test_opt(sb, POSIX_ACL))
278                 seq_puts(seq, ",acl");
279         if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
280                 seq_puts(seq, ",noacl");
281 #endif
282 
283         if (test_opt(sb, NOBH))
284                 seq_puts(seq, ",nobh");
285 
286 #if defined(CONFIG_QUOTA)
287         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
288                 seq_puts(seq, ",usrquota");
289 
290         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
291                 seq_puts(seq, ",grpquota");
292 #endif
293 
294 #ifdef CONFIG_FS_DAX
295         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
296                 seq_puts(seq, ",xip");
297         if (sbi->s_mount_opt & EXT2_MOUNT_DAX)
298                 seq_puts(seq, ",dax");
299 #endif
300 
301         if (!test_opt(sb, RESERVATION))
302                 seq_puts(seq, ",noreservation");
303 
304         spin_unlock(&sbi->s_lock);
305         return 0;
306 }
307 
308 #ifdef CONFIG_QUOTA
309 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
310 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
311 static struct dquot **ext2_get_dquots(struct inode *inode)
312 {
313         return EXT2_I(inode)->i_dquot;
314 }
315 #endif
316 
317 static const struct super_operations ext2_sops = {
318         .alloc_inode    = ext2_alloc_inode,
319         .destroy_inode  = ext2_destroy_inode,
320         .write_inode    = ext2_write_inode,
321         .evict_inode    = ext2_evict_inode,
322         .put_super      = ext2_put_super,
323         .sync_fs        = ext2_sync_fs,
324         .freeze_fs      = ext2_freeze,
325         .unfreeze_fs    = ext2_unfreeze,
326         .statfs         = ext2_statfs,
327         .remount_fs     = ext2_remount,
328         .show_options   = ext2_show_options,
329 #ifdef CONFIG_QUOTA
330         .quota_read     = ext2_quota_read,
331         .quota_write    = ext2_quota_write,
332         .get_dquots     = ext2_get_dquots,
333 #endif
334 };
335 
336 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
337                 u64 ino, u32 generation)
338 {
339         struct inode *inode;
340 
341         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
342                 return ERR_PTR(-ESTALE);
343         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
344                 return ERR_PTR(-ESTALE);
345 
346         /*
347          * ext2_iget isn't quite right if the inode is currently unallocated!
348          * However ext2_iget currently does appropriate checks to handle stale
349          * inodes so everything is OK.
350          */
351         inode = ext2_iget(sb, ino);
352         if (IS_ERR(inode))
353                 return ERR_CAST(inode);
354         if (generation && inode->i_generation != generation) {
355                 /* we didn't find the right inode.. */
356                 iput(inode);
357                 return ERR_PTR(-ESTALE);
358         }
359         return inode;
360 }
361 
362 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
363                 int fh_len, int fh_type)
364 {
365         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
366                                     ext2_nfs_get_inode);
367 }
368 
369 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
370                 int fh_len, int fh_type)
371 {
372         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
373                                     ext2_nfs_get_inode);
374 }
375 
376 static const struct export_operations ext2_export_ops = {
377         .fh_to_dentry = ext2_fh_to_dentry,
378         .fh_to_parent = ext2_fh_to_parent,
379         .get_parent = ext2_get_parent,
380 };
381 
382 static unsigned long get_sb_block(void **data)
383 {
384         unsigned long   sb_block;
385         char            *options = (char *) *data;
386 
387         if (!options || strncmp(options, "sb=", 3) != 0)
388                 return 1;       /* Default location */
389         options += 3;
390         sb_block = simple_strtoul(options, &options, 0);
391         if (*options && *options != ',') {
392                 printk("EXT2-fs: Invalid sb specification: %s\n",
393                        (char *) *data);
394                 return 1;
395         }
396         if (*options == ',')
397                 options++;
398         *data = (void *) options;
399         return sb_block;
400 }
401 
402 enum {
403         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
404         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
405         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
406         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
407         Opt_acl, Opt_noacl, Opt_xip, Opt_dax, Opt_ignore, Opt_err, Opt_quota,
408         Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
409 };
410 
411 static const match_table_t tokens = {
412         {Opt_bsd_df, "bsddf"},
413         {Opt_minix_df, "minixdf"},
414         {Opt_grpid, "grpid"},
415         {Opt_grpid, "bsdgroups"},
416         {Opt_nogrpid, "nogrpid"},
417         {Opt_nogrpid, "sysvgroups"},
418         {Opt_resgid, "resgid=%u"},
419         {Opt_resuid, "resuid=%u"},
420         {Opt_sb, "sb=%u"},
421         {Opt_err_cont, "errors=continue"},
422         {Opt_err_panic, "errors=panic"},
423         {Opt_err_ro, "errors=remount-ro"},
424         {Opt_nouid32, "nouid32"},
425         {Opt_nocheck, "check=none"},
426         {Opt_nocheck, "nocheck"},
427         {Opt_debug, "debug"},
428         {Opt_oldalloc, "oldalloc"},
429         {Opt_orlov, "orlov"},
430         {Opt_nobh, "nobh"},
431         {Opt_user_xattr, "user_xattr"},
432         {Opt_nouser_xattr, "nouser_xattr"},
433         {Opt_acl, "acl"},
434         {Opt_noacl, "noacl"},
435         {Opt_xip, "xip"},
436         {Opt_dax, "dax"},
437         {Opt_grpquota, "grpquota"},
438         {Opt_ignore, "noquota"},
439         {Opt_quota, "quota"},
440         {Opt_usrquota, "usrquota"},
441         {Opt_reservation, "reservation"},
442         {Opt_noreservation, "noreservation"},
443         {Opt_err, NULL}
444 };
445 
446 static int parse_options(char *options, struct super_block *sb)
447 {
448         char *p;
449         struct ext2_sb_info *sbi = EXT2_SB(sb);
450         substring_t args[MAX_OPT_ARGS];
451         int option;
452         kuid_t uid;
453         kgid_t gid;
454 
455         if (!options)
456                 return 1;
457 
458         while ((p = strsep (&options, ",")) != NULL) {
459                 int token;
460                 if (!*p)
461                         continue;
462 
463                 token = match_token(p, tokens, args);
464                 switch (token) {
465                 case Opt_bsd_df:
466                         clear_opt (sbi->s_mount_opt, MINIX_DF);
467                         break;
468                 case Opt_minix_df:
469                         set_opt (sbi->s_mount_opt, MINIX_DF);
470                         break;
471                 case Opt_grpid:
472                         set_opt (sbi->s_mount_opt, GRPID);
473                         break;
474                 case Opt_nogrpid:
475                         clear_opt (sbi->s_mount_opt, GRPID);
476                         break;
477                 case Opt_resuid:
478                         if (match_int(&args[0], &option))
479                                 return 0;
480                         uid = make_kuid(current_user_ns(), option);
481                         if (!uid_valid(uid)) {
482                                 ext2_msg(sb, KERN_ERR, "Invalid uid value %d", option);
483                                 return 0;
484 
485                         }
486                         sbi->s_resuid = uid;
487                         break;
488                 case Opt_resgid:
489                         if (match_int(&args[0], &option))
490                                 return 0;
491                         gid = make_kgid(current_user_ns(), option);
492                         if (!gid_valid(gid)) {
493                                 ext2_msg(sb, KERN_ERR, "Invalid gid value %d", option);
494                                 return 0;
495                         }
496                         sbi->s_resgid = gid;
497                         break;
498                 case Opt_sb:
499                         /* handled by get_sb_block() instead of here */
500                         /* *sb_block = match_int(&args[0]); */
501                         break;
502                 case Opt_err_panic:
503                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
504                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
505                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
506                         break;
507                 case Opt_err_ro:
508                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
509                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
510                         set_opt (sbi->s_mount_opt, ERRORS_RO);
511                         break;
512                 case Opt_err_cont:
513                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
514                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
515                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
516                         break;
517                 case Opt_nouid32:
518                         set_opt (sbi->s_mount_opt, NO_UID32);
519                         break;
520                 case Opt_nocheck:
521                         clear_opt (sbi->s_mount_opt, CHECK);
522                         break;
523                 case Opt_debug:
524                         set_opt (sbi->s_mount_opt, DEBUG);
525                         break;
526                 case Opt_oldalloc:
527                         set_opt (sbi->s_mount_opt, OLDALLOC);
528                         break;
529                 case Opt_orlov:
530                         clear_opt (sbi->s_mount_opt, OLDALLOC);
531                         break;
532                 case Opt_nobh:
533                         set_opt (sbi->s_mount_opt, NOBH);
534                         break;
535 #ifdef CONFIG_EXT2_FS_XATTR
536                 case Opt_user_xattr:
537                         set_opt (sbi->s_mount_opt, XATTR_USER);
538                         break;
539                 case Opt_nouser_xattr:
540                         clear_opt (sbi->s_mount_opt, XATTR_USER);
541                         break;
542 #else
543                 case Opt_user_xattr:
544                 case Opt_nouser_xattr:
545                         ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
546                                 "not supported");
547                         break;
548 #endif
549 #ifdef CONFIG_EXT2_FS_POSIX_ACL
550                 case Opt_acl:
551                         set_opt(sbi->s_mount_opt, POSIX_ACL);
552                         break;
553                 case Opt_noacl:
554                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
555                         break;
556 #else
557                 case Opt_acl:
558                 case Opt_noacl:
559                         ext2_msg(sb, KERN_INFO,
560                                 "(no)acl options not supported");
561                         break;
562 #endif
563                 case Opt_xip:
564                         ext2_msg(sb, KERN_INFO, "use dax instead of xip");
565                         set_opt(sbi->s_mount_opt, XIP);
566                         /* Fall through */
567                 case Opt_dax:
568 #ifdef CONFIG_FS_DAX
569                         set_opt(sbi->s_mount_opt, DAX);
570 #else
571                         ext2_msg(sb, KERN_INFO, "dax option not supported");
572 #endif
573                         break;
574 
575 #if defined(CONFIG_QUOTA)
576                 case Opt_quota:
577                 case Opt_usrquota:
578                         set_opt(sbi->s_mount_opt, USRQUOTA);
579                         break;
580 
581                 case Opt_grpquota:
582                         set_opt(sbi->s_mount_opt, GRPQUOTA);
583                         break;
584 #else
585                 case Opt_quota:
586                 case Opt_usrquota:
587                 case Opt_grpquota:
588                         ext2_msg(sb, KERN_INFO,
589                                 "quota operations not supported");
590                         break;
591 #endif
592 
593                 case Opt_reservation:
594                         set_opt(sbi->s_mount_opt, RESERVATION);
595                         ext2_msg(sb, KERN_INFO, "reservations ON");
596                         break;
597                 case Opt_noreservation:
598                         clear_opt(sbi->s_mount_opt, RESERVATION);
599                         ext2_msg(sb, KERN_INFO, "reservations OFF");
600                         break;
601                 case Opt_ignore:
602                         break;
603                 default:
604                         return 0;
605                 }
606         }
607         return 1;
608 }
609 
610 static int ext2_setup_super (struct super_block * sb,
611                               struct ext2_super_block * es,
612                               int read_only)
613 {
614         int res = 0;
615         struct ext2_sb_info *sbi = EXT2_SB(sb);
616 
617         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
618                 ext2_msg(sb, KERN_ERR,
619                         "error: revision level too high, "
620                         "forcing read-only mode");
621                 res = MS_RDONLY;
622         }
623         if (read_only)
624                 return res;
625         if (!(sbi->s_mount_state & EXT2_VALID_FS))
626                 ext2_msg(sb, KERN_WARNING,
627                         "warning: mounting unchecked fs, "
628                         "running e2fsck is recommended");
629         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
630                 ext2_msg(sb, KERN_WARNING,
631                         "warning: mounting fs with errors, "
632                         "running e2fsck is recommended");
633         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
634                  le16_to_cpu(es->s_mnt_count) >=
635                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
636                 ext2_msg(sb, KERN_WARNING,
637                         "warning: maximal mount count reached, "
638                         "running e2fsck is recommended");
639         else if (le32_to_cpu(es->s_checkinterval) &&
640                 (le32_to_cpu(es->s_lastcheck) +
641                         le32_to_cpu(es->s_checkinterval) <= get_seconds()))
642                 ext2_msg(sb, KERN_WARNING,
643                         "warning: checktime reached, "
644                         "running e2fsck is recommended");
645         if (!le16_to_cpu(es->s_max_mnt_count))
646                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
647         le16_add_cpu(&es->s_mnt_count, 1);
648         if (test_opt (sb, DEBUG))
649                 ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
650                         "bpg=%lu, ipg=%lu, mo=%04lx]",
651                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
652                         sbi->s_frag_size,
653                         sbi->s_groups_count,
654                         EXT2_BLOCKS_PER_GROUP(sb),
655                         EXT2_INODES_PER_GROUP(sb),
656                         sbi->s_mount_opt);
657         return res;
658 }
659 
660 static int ext2_check_descriptors(struct super_block *sb)
661 {
662         int i;
663         struct ext2_sb_info *sbi = EXT2_SB(sb);
664 
665         ext2_debug ("Checking group descriptors");
666 
667         for (i = 0; i < sbi->s_groups_count; i++) {
668                 struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
669                 ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
670                 ext2_fsblk_t last_block;
671 
672                 if (i == sbi->s_groups_count - 1)
673                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
674                 else
675                         last_block = first_block +
676                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
677 
678                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
679                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
680                 {
681                         ext2_error (sb, "ext2_check_descriptors",
682                                     "Block bitmap for group %d"
683                                     " not in group (block %lu)!",
684                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
685                         return 0;
686                 }
687                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
688                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
689                 {
690                         ext2_error (sb, "ext2_check_descriptors",
691                                     "Inode bitmap for group %d"
692                                     " not in group (block %lu)!",
693                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
694                         return 0;
695                 }
696                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
697                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
698                     last_block)
699                 {
700                         ext2_error (sb, "ext2_check_descriptors",
701                                     "Inode table for group %d"
702                                     " not in group (block %lu)!",
703                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
704                         return 0;
705                 }
706         }
707         return 1;
708 }
709 
710 /*
711  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
712  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
713  * We need to be 1 filesystem block less than the 2^32 sector limit.
714  */
715 static loff_t ext2_max_size(int bits)
716 {
717         loff_t res = EXT2_NDIR_BLOCKS;
718         int meta_blocks;
719         loff_t upper_limit;
720 
721         /* This is calculated to be the largest file size for a
722          * dense, file such that the total number of
723          * sectors in the file, including data and all indirect blocks,
724          * does not exceed 2^32 -1
725          * __u32 i_blocks representing the total number of
726          * 512 bytes blocks of the file
727          */
728         upper_limit = (1LL << 32) - 1;
729 
730         /* total blocks in file system block size */
731         upper_limit >>= (bits - 9);
732 
733 
734         /* indirect blocks */
735         meta_blocks = 1;
736         /* double indirect blocks */
737         meta_blocks += 1 + (1LL << (bits-2));
738         /* tripple indirect blocks */
739         meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
740 
741         upper_limit -= meta_blocks;
742         upper_limit <<= bits;
743 
744         res += 1LL << (bits-2);
745         res += 1LL << (2*(bits-2));
746         res += 1LL << (3*(bits-2));
747         res <<= bits;
748         if (res > upper_limit)
749                 res = upper_limit;
750 
751         if (res > MAX_LFS_FILESIZE)
752                 res = MAX_LFS_FILESIZE;
753 
754         return res;
755 }
756 
757 static unsigned long descriptor_loc(struct super_block *sb,
758                                     unsigned long logic_sb_block,
759                                     int nr)
760 {
761         struct ext2_sb_info *sbi = EXT2_SB(sb);
762         unsigned long bg, first_meta_bg;
763         int has_super = 0;
764         
765         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
766 
767         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
768             nr < first_meta_bg)
769                 return (logic_sb_block + nr + 1);
770         bg = sbi->s_desc_per_block * nr;
771         if (ext2_bg_has_super(sb, bg))
772                 has_super = 1;
773 
774         return ext2_group_first_block_no(sb, bg) + has_super;
775 }
776 
777 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
778 {
779         struct buffer_head * bh;
780         struct ext2_sb_info * sbi;
781         struct ext2_super_block * es;
782         struct inode *root;
783         unsigned long block;
784         unsigned long sb_block = get_sb_block(&data);
785         unsigned long logic_sb_block;
786         unsigned long offset = 0;
787         unsigned long def_mount_opts;
788         long ret = -EINVAL;
789         int blocksize = BLOCK_SIZE;
790         int db_count;
791         int i, j;
792         __le32 features;
793         int err;
794 
795         err = -ENOMEM;
796         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
797         if (!sbi)
798                 goto failed;
799 
800         sbi->s_blockgroup_lock =
801                 kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
802         if (!sbi->s_blockgroup_lock) {
803                 kfree(sbi);
804                 goto failed;
805         }
806         sb->s_fs_info = sbi;
807         sbi->s_sb_block = sb_block;
808 
809         spin_lock_init(&sbi->s_lock);
810 
811         /*
812          * See what the current blocksize for the device is, and
813          * use that as the blocksize.  Otherwise (or if the blocksize
814          * is smaller than the default) use the default.
815          * This is important for devices that have a hardware
816          * sectorsize that is larger than the default.
817          */
818         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
819         if (!blocksize) {
820                 ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
821                 goto failed_sbi;
822         }
823 
824         /*
825          * If the superblock doesn't start on a hardware sector boundary,
826          * calculate the offset.  
827          */
828         if (blocksize != BLOCK_SIZE) {
829                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
830                 offset = (sb_block*BLOCK_SIZE) % blocksize;
831         } else {
832                 logic_sb_block = sb_block;
833         }
834 
835         if (!(bh = sb_bread(sb, logic_sb_block))) {
836                 ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
837                 goto failed_sbi;
838         }
839         /*
840          * Note: s_es must be initialized as soon as possible because
841          *       some ext2 macro-instructions depend on its value
842          */
843         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
844         sbi->s_es = es;
845         sb->s_magic = le16_to_cpu(es->s_magic);
846 
847         if (sb->s_magic != EXT2_SUPER_MAGIC)
848                 goto cantfind_ext2;
849 
850         /* Set defaults before we parse the mount options */
851         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
852         if (def_mount_opts & EXT2_DEFM_DEBUG)
853                 set_opt(sbi->s_mount_opt, DEBUG);
854         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
855                 set_opt(sbi->s_mount_opt, GRPID);
856         if (def_mount_opts & EXT2_DEFM_UID16)
857                 set_opt(sbi->s_mount_opt, NO_UID32);
858 #ifdef CONFIG_EXT2_FS_XATTR
859         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
860                 set_opt(sbi->s_mount_opt, XATTR_USER);
861 #endif
862 #ifdef CONFIG_EXT2_FS_POSIX_ACL
863         if (def_mount_opts & EXT2_DEFM_ACL)
864                 set_opt(sbi->s_mount_opt, POSIX_ACL);
865 #endif
866         
867         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
868                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
869         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
870                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
871         else
872                 set_opt(sbi->s_mount_opt, ERRORS_RO);
873 
874         sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
875         sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
876         
877         set_opt(sbi->s_mount_opt, RESERVATION);
878 
879         if (!parse_options((char *) data, sb))
880                 goto failed_mount;
881 
882         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
883                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
884                  MS_POSIXACL : 0);
885         sb->s_iflags |= SB_I_CGROUPWB;
886 
887         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
888             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
889              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
890              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
891                 ext2_msg(sb, KERN_WARNING,
892                         "warning: feature flags set on rev 0 fs, "
893                         "running e2fsck is recommended");
894         /*
895          * Check feature flags regardless of the revision level, since we
896          * previously didn't change the revision level when setting the flags,
897          * so there is a chance incompat flags are set on a rev 0 filesystem.
898          */
899         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
900         if (features) {
901                 ext2_msg(sb, KERN_ERR,  "error: couldn't mount because of "
902                        "unsupported optional features (%x)",
903                         le32_to_cpu(features));
904                 goto failed_mount;
905         }
906         if (!(sb->s_flags & MS_RDONLY) &&
907             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
908                 ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
909                        "unsupported optional features (%x)",
910                        le32_to_cpu(features));
911                 goto failed_mount;
912         }
913 
914         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
915 
916         if (sbi->s_mount_opt & EXT2_MOUNT_DAX) {
917                 if (blocksize != PAGE_SIZE) {
918                         ext2_msg(sb, KERN_ERR,
919                                         "error: unsupported blocksize for dax");
920                         goto failed_mount;
921                 }
922                 if (!sb->s_bdev->bd_disk->fops->direct_access) {
923                         ext2_msg(sb, KERN_ERR,
924                                         "error: device does not support dax");
925                         goto failed_mount;
926                 }
927         }
928 
929         /* If the blocksize doesn't match, re-read the thing.. */
930         if (sb->s_blocksize != blocksize) {
931                 brelse(bh);
932 
933                 if (!sb_set_blocksize(sb, blocksize)) {
934                         ext2_msg(sb, KERN_ERR,
935                                 "error: bad blocksize %d", blocksize);
936                         goto failed_sbi;
937                 }
938 
939                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
940                 offset = (sb_block*BLOCK_SIZE) % blocksize;
941                 bh = sb_bread(sb, logic_sb_block);
942                 if(!bh) {
943                         ext2_msg(sb, KERN_ERR, "error: couldn't read"
944                                 "superblock on 2nd try");
945                         goto failed_sbi;
946                 }
947                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
948                 sbi->s_es = es;
949                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
950                         ext2_msg(sb, KERN_ERR, "error: magic mismatch");
951                         goto failed_mount;
952                 }
953         }
954 
955         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
956         sb->s_max_links = EXT2_LINK_MAX;
957 
958         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
959                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
960                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
961         } else {
962                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
963                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
964                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
965                     !is_power_of_2(sbi->s_inode_size) ||
966                     (sbi->s_inode_size > blocksize)) {
967                         ext2_msg(sb, KERN_ERR,
968                                 "error: unsupported inode size: %d",
969                                 sbi->s_inode_size);
970                         goto failed_mount;
971                 }
972         }
973 
974         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
975                                    le32_to_cpu(es->s_log_frag_size);
976         if (sbi->s_frag_size == 0)
977                 goto cantfind_ext2;
978         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
979 
980         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
981         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
982         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
983 
984         if (EXT2_INODE_SIZE(sb) == 0)
985                 goto cantfind_ext2;
986         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
987         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
988                 goto cantfind_ext2;
989         sbi->s_itb_per_group = sbi->s_inodes_per_group /
990                                         sbi->s_inodes_per_block;
991         sbi->s_desc_per_block = sb->s_blocksize /
992                                         sizeof (struct ext2_group_desc);
993         sbi->s_sbh = bh;
994         sbi->s_mount_state = le16_to_cpu(es->s_state);
995         sbi->s_addr_per_block_bits =
996                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
997         sbi->s_desc_per_block_bits =
998                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
999 
1000         if (sb->s_magic != EXT2_SUPER_MAGIC)
1001                 goto cantfind_ext2;
1002 
1003         if (sb->s_blocksize != bh->b_size) {
1004                 if (!silent)
1005                         ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
1006                 goto failed_mount;
1007         }
1008 
1009         if (sb->s_blocksize != sbi->s_frag_size) {
1010                 ext2_msg(sb, KERN_ERR,
1011                         "error: fragsize %lu != blocksize %lu"
1012                         "(not supported yet)",
1013                         sbi->s_frag_size, sb->s_blocksize);
1014                 goto failed_mount;
1015         }
1016 
1017         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
1018                 ext2_msg(sb, KERN_ERR,
1019                         "error: #blocks per group too big: %lu",
1020                         sbi->s_blocks_per_group);
1021                 goto failed_mount;
1022         }
1023         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
1024                 ext2_msg(sb, KERN_ERR,
1025                         "error: #fragments per group too big: %lu",
1026                         sbi->s_frags_per_group);
1027                 goto failed_mount;
1028         }
1029         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
1030                 ext2_msg(sb, KERN_ERR,
1031                         "error: #inodes per group too big: %lu",
1032                         sbi->s_inodes_per_group);
1033                 goto failed_mount;
1034         }
1035 
1036         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
1037                 goto cantfind_ext2;
1038         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
1039                                 le32_to_cpu(es->s_first_data_block) - 1)
1040                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
1041         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
1042                    EXT2_DESC_PER_BLOCK(sb);
1043         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
1044         if (sbi->s_group_desc == NULL) {
1045                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
1046                 goto failed_mount;
1047         }
1048         bgl_lock_init(sbi->s_blockgroup_lock);
1049         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1050         if (!sbi->s_debts) {
1051                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
1052                 goto failed_mount_group_desc;
1053         }
1054         for (i = 0; i < db_count; i++) {
1055                 block = descriptor_loc(sb, logic_sb_block, i);
1056                 sbi->s_group_desc[i] = sb_bread(sb, block);
1057                 if (!sbi->s_group_desc[i]) {
1058                         for (j = 0; j < i; j++)
1059                                 brelse (sbi->s_group_desc[j]);
1060                         ext2_msg(sb, KERN_ERR,
1061                                 "error: unable to read group descriptors");
1062                         goto failed_mount_group_desc;
1063                 }
1064         }
1065         if (!ext2_check_descriptors (sb)) {
1066                 ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1067                 goto failed_mount2;
1068         }
1069         sbi->s_gdb_count = db_count;
1070         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1071         spin_lock_init(&sbi->s_next_gen_lock);
1072 
1073         /* per fileystem reservation list head & lock */
1074         spin_lock_init(&sbi->s_rsv_window_lock);
1075         sbi->s_rsv_window_root = RB_ROOT;
1076         /*
1077          * Add a single, static dummy reservation to the start of the
1078          * reservation window list --- it gives us a placeholder for
1079          * append-at-start-of-list which makes the allocation logic
1080          * _much_ simpler.
1081          */
1082         sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1083         sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1084         sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1085         sbi->s_rsv_window_head.rsv_goal_size = 0;
1086         ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1087 
1088         err = percpu_counter_init(&sbi->s_freeblocks_counter,
1089                                 ext2_count_free_blocks(sb), GFP_KERNEL);
1090         if (!err) {
1091                 err = percpu_counter_init(&sbi->s_freeinodes_counter,
1092                                 ext2_count_free_inodes(sb), GFP_KERNEL);
1093         }
1094         if (!err) {
1095                 err = percpu_counter_init(&sbi->s_dirs_counter,
1096                                 ext2_count_dirs(sb), GFP_KERNEL);
1097         }
1098         if (err) {
1099                 ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1100                 goto failed_mount3;
1101         }
1102         /*
1103          * set up enough so that it can read an inode
1104          */
1105         sb->s_op = &ext2_sops;
1106         sb->s_export_op = &ext2_export_ops;
1107         sb->s_xattr = ext2_xattr_handlers;
1108 
1109 #ifdef CONFIG_QUOTA
1110         sb->dq_op = &dquot_operations;
1111         sb->s_qcop = &dquot_quotactl_ops;
1112         sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP;
1113 #endif
1114 
1115         root = ext2_iget(sb, EXT2_ROOT_INO);
1116         if (IS_ERR(root)) {
1117                 ret = PTR_ERR(root);
1118                 goto failed_mount3;
1119         }
1120         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1121                 iput(root);
1122                 ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1123                 goto failed_mount3;
1124         }
1125 
1126         sb->s_root = d_make_root(root);
1127         if (!sb->s_root) {
1128                 ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1129                 ret = -ENOMEM;
1130                 goto failed_mount3;
1131         }
1132         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1133                 ext2_msg(sb, KERN_WARNING,
1134                         "warning: mounting ext3 filesystem as ext2");
1135         if (ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY))
1136                 sb->s_flags |= MS_RDONLY;
1137         ext2_write_super(sb);
1138         return 0;
1139 
1140 cantfind_ext2:
1141         if (!silent)
1142                 ext2_msg(sb, KERN_ERR,
1143                         "error: can't find an ext2 filesystem on dev %s.",
1144                         sb->s_id);
1145         goto failed_mount;
1146 failed_mount3:
1147         percpu_counter_destroy(&sbi->s_freeblocks_counter);
1148         percpu_counter_destroy(&sbi->s_freeinodes_counter);
1149         percpu_counter_destroy(&sbi->s_dirs_counter);
1150 failed_mount2:
1151         for (i = 0; i < db_count; i++)
1152                 brelse(sbi->s_group_desc[i]);
1153 failed_mount_group_desc:
1154         kfree(sbi->s_group_desc);
1155         kfree(sbi->s_debts);
1156 failed_mount:
1157         brelse(bh);
1158 failed_sbi:
1159         sb->s_fs_info = NULL;
1160         kfree(sbi->s_blockgroup_lock);
1161         kfree(sbi);
1162 failed:
1163         return ret;
1164 }
1165 
1166 static void ext2_clear_super_error(struct super_block *sb)
1167 {
1168         struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1169 
1170         if (buffer_write_io_error(sbh)) {
1171                 /*
1172                  * Oh, dear.  A previous attempt to write the
1173                  * superblock failed.  This could happen because the
1174                  * USB device was yanked out.  Or it could happen to
1175                  * be a transient write error and maybe the block will
1176                  * be remapped.  Nothing we can do but to retry the
1177                  * write and hope for the best.
1178                  */
1179                 ext2_msg(sb, KERN_ERR,
1180                        "previous I/O error to superblock detected\n");
1181                 clear_buffer_write_io_error(sbh);
1182                 set_buffer_uptodate(sbh);
1183         }
1184 }
1185 
1186 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
1187                             int wait)
1188 {
1189         ext2_clear_super_error(sb);
1190         spin_lock(&EXT2_SB(sb)->s_lock);
1191         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1192         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1193         es->s_wtime = cpu_to_le32(get_seconds());
1194         /* unlock before we do IO */
1195         spin_unlock(&EXT2_SB(sb)->s_lock);
1196         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1197         if (wait)
1198                 sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1199 }
1200 
1201 /*
1202  * In the second extended file system, it is not necessary to
1203  * write the super block since we use a mapping of the
1204  * disk super block in a buffer.
1205  *
1206  * However, this function is still used to set the fs valid
1207  * flags to 0.  We need to set this flag to 0 since the fs
1208  * may have been checked while mounted and e2fsck may have
1209  * set s_state to EXT2_VALID_FS after some corrections.
1210  */
1211 static int ext2_sync_fs(struct super_block *sb, int wait)
1212 {
1213         struct ext2_sb_info *sbi = EXT2_SB(sb);
1214         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1215 
1216         /*
1217          * Write quota structures to quota file, sync_blockdev() will write
1218          * them to disk later
1219          */
1220         dquot_writeback_dquots(sb, -1);
1221 
1222         spin_lock(&sbi->s_lock);
1223         if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1224                 ext2_debug("setting valid to 0\n");
1225                 es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1226         }
1227         spin_unlock(&sbi->s_lock);
1228         ext2_sync_super(sb, es, wait);
1229         return 0;
1230 }
1231 
1232 static int ext2_freeze(struct super_block *sb)
1233 {
1234         struct ext2_sb_info *sbi = EXT2_SB(sb);
1235 
1236         /*
1237          * Open but unlinked files present? Keep EXT2_VALID_FS flag cleared
1238          * because we have unattached inodes and thus filesystem is not fully
1239          * consistent.
1240          */
1241         if (atomic_long_read(&sb->s_remove_count)) {
1242                 ext2_sync_fs(sb, 1);
1243                 return 0;
1244         }
1245         /* Set EXT2_FS_VALID flag */
1246         spin_lock(&sbi->s_lock);
1247         sbi->s_es->s_state = cpu_to_le16(sbi->s_mount_state);
1248         spin_unlock(&sbi->s_lock);
1249         ext2_sync_super(sb, sbi->s_es, 1);
1250 
1251         return 0;
1252 }
1253 
1254 static int ext2_unfreeze(struct super_block *sb)
1255 {
1256         /* Just write sb to clear EXT2_VALID_FS flag */
1257         ext2_write_super(sb);
1258 
1259         return 0;
1260 }
1261 
1262 void ext2_write_super(struct super_block *sb)
1263 {
1264         if (!(sb->s_flags & MS_RDONLY))
1265                 ext2_sync_fs(sb, 1);
1266 }
1267 
1268 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1269 {
1270         struct ext2_sb_info * sbi = EXT2_SB(sb);
1271         struct ext2_super_block * es;
1272         struct ext2_mount_options old_opts;
1273         unsigned long old_sb_flags;
1274         int err;
1275 
1276         sync_filesystem(sb);
1277         spin_lock(&sbi->s_lock);
1278 
1279         /* Store the old options */
1280         old_sb_flags = sb->s_flags;
1281         old_opts.s_mount_opt = sbi->s_mount_opt;
1282         old_opts.s_resuid = sbi->s_resuid;
1283         old_opts.s_resgid = sbi->s_resgid;
1284 
1285         /*
1286          * Allow the "check" option to be passed as a remount option.
1287          */
1288         if (!parse_options(data, sb)) {
1289                 err = -EINVAL;
1290                 goto restore_opts;
1291         }
1292 
1293         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1294                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1295 
1296         es = sbi->s_es;
1297         if ((sbi->s_mount_opt ^ old_opts.s_mount_opt) & EXT2_MOUNT_DAX) {
1298                 ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1299                          "dax flag with busy inodes while remounting");
1300                 sbi->s_mount_opt ^= EXT2_MOUNT_DAX;
1301         }
1302         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
1303                 spin_unlock(&sbi->s_lock);
1304                 return 0;
1305         }
1306         if (*flags & MS_RDONLY) {
1307                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1308                     !(sbi->s_mount_state & EXT2_VALID_FS)) {
1309                         spin_unlock(&sbi->s_lock);
1310                         return 0;
1311                 }
1312 
1313                 /*
1314                  * OK, we are remounting a valid rw partition rdonly, so set
1315                  * the rdonly flag and then mark the partition as valid again.
1316                  */
1317                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1318                 es->s_mtime = cpu_to_le32(get_seconds());
1319                 spin_unlock(&sbi->s_lock);
1320 
1321                 err = dquot_suspend(sb, -1);
1322                 if (err < 0) {
1323                         spin_lock(&sbi->s_lock);
1324                         goto restore_opts;
1325                 }
1326 
1327                 ext2_sync_super(sb, es, 1);
1328         } else {
1329                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1330                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1331                 if (ret) {
1332                         ext2_msg(sb, KERN_WARNING,
1333                                 "warning: couldn't remount RDWR because of "
1334                                 "unsupported optional features (%x).",
1335                                 le32_to_cpu(ret));
1336                         err = -EROFS;
1337                         goto restore_opts;
1338                 }
1339                 /*
1340                  * Mounting a RDONLY partition read-write, so reread and
1341                  * store the current valid flag.  (It may have been changed
1342                  * by e2fsck since we originally mounted the partition.)
1343                  */
1344                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1345                 if (!ext2_setup_super (sb, es, 0))
1346                         sb->s_flags &= ~MS_RDONLY;
1347                 spin_unlock(&sbi->s_lock);
1348 
1349                 ext2_write_super(sb);
1350 
1351                 dquot_resume(sb, -1);
1352         }
1353 
1354         return 0;
1355 restore_opts:
1356         sbi->s_mount_opt = old_opts.s_mount_opt;
1357         sbi->s_resuid = old_opts.s_resuid;
1358         sbi->s_resgid = old_opts.s_resgid;
1359         sb->s_flags = old_sb_flags;
1360         spin_unlock(&sbi->s_lock);
1361         return err;
1362 }
1363 
1364 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1365 {
1366         struct super_block *sb = dentry->d_sb;
1367         struct ext2_sb_info *sbi = EXT2_SB(sb);
1368         struct ext2_super_block *es = sbi->s_es;
1369         u64 fsid;
1370 
1371         spin_lock(&sbi->s_lock);
1372 
1373         if (test_opt (sb, MINIX_DF))
1374                 sbi->s_overhead_last = 0;
1375         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1376                 unsigned long i, overhead = 0;
1377                 smp_rmb();
1378 
1379                 /*
1380                  * Compute the overhead (FS structures). This is constant
1381                  * for a given filesystem unless the number of block groups
1382                  * changes so we cache the previous value until it does.
1383                  */
1384 
1385                 /*
1386                  * All of the blocks before first_data_block are
1387                  * overhead
1388                  */
1389                 overhead = le32_to_cpu(es->s_first_data_block);
1390 
1391                 /*
1392                  * Add the overhead attributed to the superblock and
1393                  * block group descriptors.  If the sparse superblocks
1394                  * feature is turned on, then not all groups have this.
1395                  */
1396                 for (i = 0; i < sbi->s_groups_count; i++)
1397                         overhead += ext2_bg_has_super(sb, i) +
1398                                 ext2_bg_num_gdb(sb, i);
1399 
1400                 /*
1401                  * Every block group has an inode bitmap, a block
1402                  * bitmap, and an inode table.
1403                  */
1404                 overhead += (sbi->s_groups_count *
1405                              (2 + sbi->s_itb_per_group));
1406                 sbi->s_overhead_last = overhead;
1407                 smp_wmb();
1408                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1409         }
1410 
1411         buf->f_type = EXT2_SUPER_MAGIC;
1412         buf->f_bsize = sb->s_blocksize;
1413         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1414         buf->f_bfree = ext2_count_free_blocks(sb);
1415         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1416         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1417         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1418                 buf->f_bavail = 0;
1419         buf->f_files = le32_to_cpu(es->s_inodes_count);
1420         buf->f_ffree = ext2_count_free_inodes(sb);
1421         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1422         buf->f_namelen = EXT2_NAME_LEN;
1423         fsid = le64_to_cpup((void *)es->s_uuid) ^
1424                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1425         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1426         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1427         spin_unlock(&sbi->s_lock);
1428         return 0;
1429 }
1430 
1431 static struct dentry *ext2_mount(struct file_system_type *fs_type,
1432         int flags, const char *dev_name, void *data)
1433 {
1434         return mount_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1435 }
1436 
1437 #ifdef CONFIG_QUOTA
1438 
1439 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1440  * acquiring the locks... As quota files are never truncated and quota code
1441  * itself serializes the operations (and no one else should touch the files)
1442  * we don't have to be afraid of races */
1443 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1444                                size_t len, loff_t off)
1445 {
1446         struct inode *inode = sb_dqopt(sb)->files[type];
1447         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1448         int err = 0;
1449         int offset = off & (sb->s_blocksize - 1);
1450         int tocopy;
1451         size_t toread;
1452         struct buffer_head tmp_bh;
1453         struct buffer_head *bh;
1454         loff_t i_size = i_size_read(inode);
1455 
1456         if (off > i_size)
1457                 return 0;
1458         if (off+len > i_size)
1459                 len = i_size-off;
1460         toread = len;
1461         while (toread > 0) {
1462                 tocopy = sb->s_blocksize - offset < toread ?
1463                                 sb->s_blocksize - offset : toread;
1464 
1465                 tmp_bh.b_state = 0;
1466                 tmp_bh.b_size = sb->s_blocksize;
1467                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1468                 if (err < 0)
1469                         return err;
1470                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1471                         memset(data, 0, tocopy);
1472                 else {
1473                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1474                         if (!bh)
1475                                 return -EIO;
1476                         memcpy(data, bh->b_data+offset, tocopy);
1477                         brelse(bh);
1478                 }
1479                 offset = 0;
1480                 toread -= tocopy;
1481                 data += tocopy;
1482                 blk++;
1483         }
1484         return len;
1485 }
1486 
1487 /* Write to quotafile */
1488 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1489                                 const char *data, size_t len, loff_t off)
1490 {
1491         struct inode *inode = sb_dqopt(sb)->files[type];
1492         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1493         int err = 0;
1494         int offset = off & (sb->s_blocksize - 1);
1495         int tocopy;
1496         size_t towrite = len;
1497         struct buffer_head tmp_bh;
1498         struct buffer_head *bh;
1499 
1500         while (towrite > 0) {
1501                 tocopy = sb->s_blocksize - offset < towrite ?
1502                                 sb->s_blocksize - offset : towrite;
1503 
1504                 tmp_bh.b_state = 0;
1505                 tmp_bh.b_size = sb->s_blocksize;
1506                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1507                 if (err < 0)
1508                         goto out;
1509                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1510                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1511                 else
1512                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1513                 if (unlikely(!bh)) {
1514                         err = -EIO;
1515                         goto out;
1516                 }
1517                 lock_buffer(bh);
1518                 memcpy(bh->b_data+offset, data, tocopy);
1519                 flush_dcache_page(bh->b_page);
1520                 set_buffer_uptodate(bh);
1521                 mark_buffer_dirty(bh);
1522                 unlock_buffer(bh);
1523                 brelse(bh);
1524                 offset = 0;
1525                 towrite -= tocopy;
1526                 data += tocopy;
1527                 blk++;
1528         }
1529 out:
1530         if (len == towrite)
1531                 return err;
1532         if (inode->i_size < off+len-towrite)
1533                 i_size_write(inode, off+len-towrite);
1534         inode->i_version++;
1535         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1536         mark_inode_dirty(inode);
1537         return len - towrite;
1538 }
1539 
1540 #endif
1541 
1542 static struct file_system_type ext2_fs_type = {
1543         .owner          = THIS_MODULE,
1544         .name           = "ext2",
1545         .mount          = ext2_mount,
1546         .kill_sb        = kill_block_super,
1547         .fs_flags       = FS_REQUIRES_DEV,
1548 };
1549 MODULE_ALIAS_FS("ext2");
1550 
1551 static int __init init_ext2_fs(void)
1552 {
1553         int err = init_ext2_xattr();
1554         if (err)
1555                 return err;
1556         err = init_inodecache();
1557         if (err)
1558                 goto out1;
1559         err = register_filesystem(&ext2_fs_type);
1560         if (err)
1561                 goto out;
1562         return 0;
1563 out:
1564         destroy_inodecache();
1565 out1:
1566         exit_ext2_xattr();
1567         return err;
1568 }
1569 
1570 static void __exit exit_ext2_fs(void)
1571 {
1572         unregister_filesystem(&ext2_fs_type);
1573         destroy_inodecache();
1574         exit_ext2_xattr();
1575 }
1576 
1577 MODULE_AUTHOR("Remy Card and others");
1578 MODULE_DESCRIPTION("Second Extended Filesystem");
1579 MODULE_LICENSE("GPL");
1580 module_init(init_ext2_fs)
1581 module_exit(exit_ext2_fs)
1582 

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