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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         if (sbi->s_mb_cache) {
135                 ext2_xattr_destroy_cache(sbi->s_mb_cache);
136                 sbi->s_mb_cache = NULL;
137         }
138         if (!(sb->s_flags & MS_RDONLY)) {
139                 struct ext2_super_block *es = sbi->s_es;
140 
141                 spin_lock(&sbi->s_lock);
142                 es->s_state = cpu_to_le16(sbi->s_mount_state);
143                 spin_unlock(&sbi->s_lock);
144                 ext2_sync_super(sb, es, 1);
145         }
146         db_count = sbi->s_gdb_count;
147         for (i = 0; i < db_count; i++)
148                 if (sbi->s_group_desc[i])
149                         brelse (sbi->s_group_desc[i]);
150         kfree(sbi->s_group_desc);
151         kfree(sbi->s_debts);
152         percpu_counter_destroy(&sbi->s_freeblocks_counter);
153         percpu_counter_destroy(&sbi->s_freeinodes_counter);
154         percpu_counter_destroy(&sbi->s_dirs_counter);
155         brelse (sbi->s_sbh);
156         sb->s_fs_info = NULL;
157         kfree(sbi->s_blockgroup_lock);
158         kfree(sbi);
159 }
160 
161 static struct kmem_cache * ext2_inode_cachep;
162 
163 static struct inode *ext2_alloc_inode(struct super_block *sb)
164 {
165         struct ext2_inode_info *ei;
166         ei = kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
167         if (!ei)
168                 return NULL;
169         ei->i_block_alloc_info = NULL;
170         ei->vfs_inode.i_version = 1;
171 #ifdef CONFIG_QUOTA
172         memset(&ei->i_dquot, 0, sizeof(ei->i_dquot));
173 #endif
174 
175         return &ei->vfs_inode;
176 }
177 
178 static void ext2_i_callback(struct rcu_head *head)
179 {
180         struct inode *inode = container_of(head, struct inode, i_rcu);
181         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
182 }
183 
184 static void ext2_destroy_inode(struct inode *inode)
185 {
186         call_rcu(&inode->i_rcu, ext2_i_callback);
187 }
188 
189 static void init_once(void *foo)
190 {
191         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
192 
193         rwlock_init(&ei->i_meta_lock);
194 #ifdef CONFIG_EXT2_FS_XATTR
195         init_rwsem(&ei->xattr_sem);
196 #endif
197         mutex_init(&ei->truncate_mutex);
198 #ifdef CONFIG_FS_DAX
199         init_rwsem(&ei->dax_sem);
200 #endif
201         inode_init_once(&ei->vfs_inode);
202 }
203 
204 static int __init init_inodecache(void)
205 {
206         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
207                                              sizeof(struct ext2_inode_info),
208                                              0, (SLAB_RECLAIM_ACCOUNT|
209                                                 SLAB_MEM_SPREAD|SLAB_ACCOUNT),
210                                              init_once);
211         if (ext2_inode_cachep == NULL)
212                 return -ENOMEM;
213         return 0;
214 }
215 
216 static void destroy_inodecache(void)
217 {
218         /*
219          * Make sure all delayed rcu free inodes are flushed before we
220          * destroy cache.
221          */
222         rcu_barrier();
223         kmem_cache_destroy(ext2_inode_cachep);
224 }
225 
226 static int ext2_show_options(struct seq_file *seq, struct dentry *root)
227 {
228         struct super_block *sb = root->d_sb;
229         struct ext2_sb_info *sbi = EXT2_SB(sb);
230         struct ext2_super_block *es = sbi->s_es;
231         unsigned long def_mount_opts;
232 
233         spin_lock(&sbi->s_lock);
234         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
235 
236         if (sbi->s_sb_block != 1)
237                 seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
238         if (test_opt(sb, MINIX_DF))
239                 seq_puts(seq, ",minixdf");
240         if (test_opt(sb, GRPID))
241                 seq_puts(seq, ",grpid");
242         if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
243                 seq_puts(seq, ",nogrpid");
244         if (!uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT2_DEF_RESUID)) ||
245             le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
246                 seq_printf(seq, ",resuid=%u",
247                                 from_kuid_munged(&init_user_ns, sbi->s_resuid));
248         }
249         if (!gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT2_DEF_RESGID)) ||
250             le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
251                 seq_printf(seq, ",resgid=%u",
252                                 from_kgid_munged(&init_user_ns, sbi->s_resgid));
253         }
254         if (test_opt(sb, ERRORS_RO)) {
255                 int def_errors = le16_to_cpu(es->s_errors);
256 
257                 if (def_errors == EXT2_ERRORS_PANIC ||
258                     def_errors == EXT2_ERRORS_CONTINUE) {
259                         seq_puts(seq, ",errors=remount-ro");
260                 }
261         }
262         if (test_opt(sb, ERRORS_CONT))
263                 seq_puts(seq, ",errors=continue");
264         if (test_opt(sb, ERRORS_PANIC))
265                 seq_puts(seq, ",errors=panic");
266         if (test_opt(sb, NO_UID32))
267                 seq_puts(seq, ",nouid32");
268         if (test_opt(sb, DEBUG))
269                 seq_puts(seq, ",debug");
270         if (test_opt(sb, OLDALLOC))
271                 seq_puts(seq, ",oldalloc");
272 
273 #ifdef CONFIG_EXT2_FS_XATTR
274         if (test_opt(sb, XATTR_USER))
275                 seq_puts(seq, ",user_xattr");
276         if (!test_opt(sb, XATTR_USER) &&
277             (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
278                 seq_puts(seq, ",nouser_xattr");
279         }
280 #endif
281 
282 #ifdef CONFIG_EXT2_FS_POSIX_ACL
283         if (test_opt(sb, POSIX_ACL))
284                 seq_puts(seq, ",acl");
285         if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
286                 seq_puts(seq, ",noacl");
287 #endif
288 
289         if (test_opt(sb, NOBH))
290                 seq_puts(seq, ",nobh");
291 
292 #if defined(CONFIG_QUOTA)
293         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
294                 seq_puts(seq, ",usrquota");
295 
296         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
297                 seq_puts(seq, ",grpquota");
298 #endif
299 
300 #ifdef CONFIG_FS_DAX
301         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
302                 seq_puts(seq, ",xip");
303         if (sbi->s_mount_opt & EXT2_MOUNT_DAX)
304                 seq_puts(seq, ",dax");
305 #endif
306 
307         if (!test_opt(sb, RESERVATION))
308                 seq_puts(seq, ",noreservation");
309 
310         spin_unlock(&sbi->s_lock);
311         return 0;
312 }
313 
314 #ifdef CONFIG_QUOTA
315 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
316 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
317 static struct dquot **ext2_get_dquots(struct inode *inode)
318 {
319         return EXT2_I(inode)->i_dquot;
320 }
321 #endif
322 
323 static const struct super_operations ext2_sops = {
324         .alloc_inode    = ext2_alloc_inode,
325         .destroy_inode  = ext2_destroy_inode,
326         .write_inode    = ext2_write_inode,
327         .evict_inode    = ext2_evict_inode,
328         .put_super      = ext2_put_super,
329         .sync_fs        = ext2_sync_fs,
330         .freeze_fs      = ext2_freeze,
331         .unfreeze_fs    = ext2_unfreeze,
332         .statfs         = ext2_statfs,
333         .remount_fs     = ext2_remount,
334         .show_options   = ext2_show_options,
335 #ifdef CONFIG_QUOTA
336         .quota_read     = ext2_quota_read,
337         .quota_write    = ext2_quota_write,
338         .get_dquots     = ext2_get_dquots,
339 #endif
340 };
341 
342 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
343                 u64 ino, u32 generation)
344 {
345         struct inode *inode;
346 
347         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
348                 return ERR_PTR(-ESTALE);
349         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
350                 return ERR_PTR(-ESTALE);
351 
352         /*
353          * ext2_iget isn't quite right if the inode is currently unallocated!
354          * However ext2_iget currently does appropriate checks to handle stale
355          * inodes so everything is OK.
356          */
357         inode = ext2_iget(sb, ino);
358         if (IS_ERR(inode))
359                 return ERR_CAST(inode);
360         if (generation && inode->i_generation != generation) {
361                 /* we didn't find the right inode.. */
362                 iput(inode);
363                 return ERR_PTR(-ESTALE);
364         }
365         return inode;
366 }
367 
368 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
369                 int fh_len, int fh_type)
370 {
371         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
372                                     ext2_nfs_get_inode);
373 }
374 
375 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
376                 int fh_len, int fh_type)
377 {
378         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
379                                     ext2_nfs_get_inode);
380 }
381 
382 static const struct export_operations ext2_export_ops = {
383         .fh_to_dentry = ext2_fh_to_dentry,
384         .fh_to_parent = ext2_fh_to_parent,
385         .get_parent = ext2_get_parent,
386 };
387 
388 static unsigned long get_sb_block(void **data)
389 {
390         unsigned long   sb_block;
391         char            *options = (char *) *data;
392 
393         if (!options || strncmp(options, "sb=", 3) != 0)
394                 return 1;       /* Default location */
395         options += 3;
396         sb_block = simple_strtoul(options, &options, 0);
397         if (*options && *options != ',') {
398                 printk("EXT2-fs: Invalid sb specification: %s\n",
399                        (char *) *data);
400                 return 1;
401         }
402         if (*options == ',')
403                 options++;
404         *data = (void *) options;
405         return sb_block;
406 }
407 
408 enum {
409         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
410         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
411         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
412         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
413         Opt_acl, Opt_noacl, Opt_xip, Opt_dax, Opt_ignore, Opt_err, Opt_quota,
414         Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
415 };
416 
417 static const match_table_t tokens = {
418         {Opt_bsd_df, "bsddf"},
419         {Opt_minix_df, "minixdf"},
420         {Opt_grpid, "grpid"},
421         {Opt_grpid, "bsdgroups"},
422         {Opt_nogrpid, "nogrpid"},
423         {Opt_nogrpid, "sysvgroups"},
424         {Opt_resgid, "resgid=%u"},
425         {Opt_resuid, "resuid=%u"},
426         {Opt_sb, "sb=%u"},
427         {Opt_err_cont, "errors=continue"},
428         {Opt_err_panic, "errors=panic"},
429         {Opt_err_ro, "errors=remount-ro"},
430         {Opt_nouid32, "nouid32"},
431         {Opt_nocheck, "check=none"},
432         {Opt_nocheck, "nocheck"},
433         {Opt_debug, "debug"},
434         {Opt_oldalloc, "oldalloc"},
435         {Opt_orlov, "orlov"},
436         {Opt_nobh, "nobh"},
437         {Opt_user_xattr, "user_xattr"},
438         {Opt_nouser_xattr, "nouser_xattr"},
439         {Opt_acl, "acl"},
440         {Opt_noacl, "noacl"},
441         {Opt_xip, "xip"},
442         {Opt_dax, "dax"},
443         {Opt_grpquota, "grpquota"},
444         {Opt_ignore, "noquota"},
445         {Opt_quota, "quota"},
446         {Opt_usrquota, "usrquota"},
447         {Opt_reservation, "reservation"},
448         {Opt_noreservation, "noreservation"},
449         {Opt_err, NULL}
450 };
451 
452 static int parse_options(char *options, struct super_block *sb)
453 {
454         char *p;
455         struct ext2_sb_info *sbi = EXT2_SB(sb);
456         substring_t args[MAX_OPT_ARGS];
457         int option;
458         kuid_t uid;
459         kgid_t gid;
460 
461         if (!options)
462                 return 1;
463 
464         while ((p = strsep (&options, ",")) != NULL) {
465                 int token;
466                 if (!*p)
467                         continue;
468 
469                 token = match_token(p, tokens, args);
470                 switch (token) {
471                 case Opt_bsd_df:
472                         clear_opt (sbi->s_mount_opt, MINIX_DF);
473                         break;
474                 case Opt_minix_df:
475                         set_opt (sbi->s_mount_opt, MINIX_DF);
476                         break;
477                 case Opt_grpid:
478                         set_opt (sbi->s_mount_opt, GRPID);
479                         break;
480                 case Opt_nogrpid:
481                         clear_opt (sbi->s_mount_opt, GRPID);
482                         break;
483                 case Opt_resuid:
484                         if (match_int(&args[0], &option))
485                                 return 0;
486                         uid = make_kuid(current_user_ns(), option);
487                         if (!uid_valid(uid)) {
488                                 ext2_msg(sb, KERN_ERR, "Invalid uid value %d", option);
489                                 return 0;
490 
491                         }
492                         sbi->s_resuid = uid;
493                         break;
494                 case Opt_resgid:
495                         if (match_int(&args[0], &option))
496                                 return 0;
497                         gid = make_kgid(current_user_ns(), option);
498                         if (!gid_valid(gid)) {
499                                 ext2_msg(sb, KERN_ERR, "Invalid gid value %d", option);
500                                 return 0;
501                         }
502                         sbi->s_resgid = gid;
503                         break;
504                 case Opt_sb:
505                         /* handled by get_sb_block() instead of here */
506                         /* *sb_block = match_int(&args[0]); */
507                         break;
508                 case Opt_err_panic:
509                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
510                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
511                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
512                         break;
513                 case Opt_err_ro:
514                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
515                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
516                         set_opt (sbi->s_mount_opt, ERRORS_RO);
517                         break;
518                 case Opt_err_cont:
519                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
520                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
521                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
522                         break;
523                 case Opt_nouid32:
524                         set_opt (sbi->s_mount_opt, NO_UID32);
525                         break;
526                 case Opt_nocheck:
527                         clear_opt (sbi->s_mount_opt, CHECK);
528                         break;
529                 case Opt_debug:
530                         set_opt (sbi->s_mount_opt, DEBUG);
531                         break;
532                 case Opt_oldalloc:
533                         set_opt (sbi->s_mount_opt, OLDALLOC);
534                         break;
535                 case Opt_orlov:
536                         clear_opt (sbi->s_mount_opt, OLDALLOC);
537                         break;
538                 case Opt_nobh:
539                         set_opt (sbi->s_mount_opt, NOBH);
540                         break;
541 #ifdef CONFIG_EXT2_FS_XATTR
542                 case Opt_user_xattr:
543                         set_opt (sbi->s_mount_opt, XATTR_USER);
544                         break;
545                 case Opt_nouser_xattr:
546                         clear_opt (sbi->s_mount_opt, XATTR_USER);
547                         break;
548 #else
549                 case Opt_user_xattr:
550                 case Opt_nouser_xattr:
551                         ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
552                                 "not supported");
553                         break;
554 #endif
555 #ifdef CONFIG_EXT2_FS_POSIX_ACL
556                 case Opt_acl:
557                         set_opt(sbi->s_mount_opt, POSIX_ACL);
558                         break;
559                 case Opt_noacl:
560                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
561                         break;
562 #else
563                 case Opt_acl:
564                 case Opt_noacl:
565                         ext2_msg(sb, KERN_INFO,
566                                 "(no)acl options not supported");
567                         break;
568 #endif
569                 case Opt_xip:
570                         ext2_msg(sb, KERN_INFO, "use dax instead of xip");
571                         set_opt(sbi->s_mount_opt, XIP);
572                         /* Fall through */
573                 case Opt_dax:
574 #ifdef CONFIG_FS_DAX
575                         ext2_msg(sb, KERN_WARNING,
576                 "DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
577                         set_opt(sbi->s_mount_opt, DAX);
578 #else
579                         ext2_msg(sb, KERN_INFO, "dax option not supported");
580 #endif
581                         break;
582 
583 #if defined(CONFIG_QUOTA)
584                 case Opt_quota:
585                 case Opt_usrquota:
586                         set_opt(sbi->s_mount_opt, USRQUOTA);
587                         break;
588 
589                 case Opt_grpquota:
590                         set_opt(sbi->s_mount_opt, GRPQUOTA);
591                         break;
592 #else
593                 case Opt_quota:
594                 case Opt_usrquota:
595                 case Opt_grpquota:
596                         ext2_msg(sb, KERN_INFO,
597                                 "quota operations not supported");
598                         break;
599 #endif
600 
601                 case Opt_reservation:
602                         set_opt(sbi->s_mount_opt, RESERVATION);
603                         ext2_msg(sb, KERN_INFO, "reservations ON");
604                         break;
605                 case Opt_noreservation:
606                         clear_opt(sbi->s_mount_opt, RESERVATION);
607                         ext2_msg(sb, KERN_INFO, "reservations OFF");
608                         break;
609                 case Opt_ignore:
610                         break;
611                 default:
612                         return 0;
613                 }
614         }
615         return 1;
616 }
617 
618 static int ext2_setup_super (struct super_block * sb,
619                               struct ext2_super_block * es,
620                               int read_only)
621 {
622         int res = 0;
623         struct ext2_sb_info *sbi = EXT2_SB(sb);
624 
625         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
626                 ext2_msg(sb, KERN_ERR,
627                         "error: revision level too high, "
628                         "forcing read-only mode");
629                 res = MS_RDONLY;
630         }
631         if (read_only)
632                 return res;
633         if (!(sbi->s_mount_state & EXT2_VALID_FS))
634                 ext2_msg(sb, KERN_WARNING,
635                         "warning: mounting unchecked fs, "
636                         "running e2fsck is recommended");
637         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
638                 ext2_msg(sb, KERN_WARNING,
639                         "warning: mounting fs with errors, "
640                         "running e2fsck is recommended");
641         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
642                  le16_to_cpu(es->s_mnt_count) >=
643                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
644                 ext2_msg(sb, KERN_WARNING,
645                         "warning: maximal mount count reached, "
646                         "running e2fsck is recommended");
647         else if (le32_to_cpu(es->s_checkinterval) &&
648                 (le32_to_cpu(es->s_lastcheck) +
649                         le32_to_cpu(es->s_checkinterval) <= get_seconds()))
650                 ext2_msg(sb, KERN_WARNING,
651                         "warning: checktime reached, "
652                         "running e2fsck is recommended");
653         if (!le16_to_cpu(es->s_max_mnt_count))
654                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
655         le16_add_cpu(&es->s_mnt_count, 1);
656         if (test_opt (sb, DEBUG))
657                 ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
658                         "bpg=%lu, ipg=%lu, mo=%04lx]",
659                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
660                         sbi->s_frag_size,
661                         sbi->s_groups_count,
662                         EXT2_BLOCKS_PER_GROUP(sb),
663                         EXT2_INODES_PER_GROUP(sb),
664                         sbi->s_mount_opt);
665         return res;
666 }
667 
668 static int ext2_check_descriptors(struct super_block *sb)
669 {
670         int i;
671         struct ext2_sb_info *sbi = EXT2_SB(sb);
672 
673         ext2_debug ("Checking group descriptors");
674 
675         for (i = 0; i < sbi->s_groups_count; i++) {
676                 struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
677                 ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
678                 ext2_fsblk_t last_block;
679 
680                 if (i == sbi->s_groups_count - 1)
681                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
682                 else
683                         last_block = first_block +
684                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
685 
686                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
687                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
688                 {
689                         ext2_error (sb, "ext2_check_descriptors",
690                                     "Block bitmap for group %d"
691                                     " not in group (block %lu)!",
692                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
693                         return 0;
694                 }
695                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
696                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
697                 {
698                         ext2_error (sb, "ext2_check_descriptors",
699                                     "Inode bitmap for group %d"
700                                     " not in group (block %lu)!",
701                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
702                         return 0;
703                 }
704                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
705                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
706                     last_block)
707                 {
708                         ext2_error (sb, "ext2_check_descriptors",
709                                     "Inode table for group %d"
710                                     " not in group (block %lu)!",
711                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
712                         return 0;
713                 }
714         }
715         return 1;
716 }
717 
718 /*
719  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
720  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
721  * We need to be 1 filesystem block less than the 2^32 sector limit.
722  */
723 static loff_t ext2_max_size(int bits)
724 {
725         loff_t res = EXT2_NDIR_BLOCKS;
726         int meta_blocks;
727         loff_t upper_limit;
728 
729         /* This is calculated to be the largest file size for a
730          * dense, file such that the total number of
731          * sectors in the file, including data and all indirect blocks,
732          * does not exceed 2^32 -1
733          * __u32 i_blocks representing the total number of
734          * 512 bytes blocks of the file
735          */
736         upper_limit = (1LL << 32) - 1;
737 
738         /* total blocks in file system block size */
739         upper_limit >>= (bits - 9);
740 
741 
742         /* indirect blocks */
743         meta_blocks = 1;
744         /* double indirect blocks */
745         meta_blocks += 1 + (1LL << (bits-2));
746         /* tripple indirect blocks */
747         meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
748 
749         upper_limit -= meta_blocks;
750         upper_limit <<= bits;
751 
752         res += 1LL << (bits-2);
753         res += 1LL << (2*(bits-2));
754         res += 1LL << (3*(bits-2));
755         res <<= bits;
756         if (res > upper_limit)
757                 res = upper_limit;
758 
759         if (res > MAX_LFS_FILESIZE)
760                 res = MAX_LFS_FILESIZE;
761 
762         return res;
763 }
764 
765 static unsigned long descriptor_loc(struct super_block *sb,
766                                     unsigned long logic_sb_block,
767                                     int nr)
768 {
769         struct ext2_sb_info *sbi = EXT2_SB(sb);
770         unsigned long bg, first_meta_bg;
771         int has_super = 0;
772         
773         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
774 
775         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
776             nr < first_meta_bg)
777                 return (logic_sb_block + nr + 1);
778         bg = sbi->s_desc_per_block * nr;
779         if (ext2_bg_has_super(sb, bg))
780                 has_super = 1;
781 
782         return ext2_group_first_block_no(sb, bg) + has_super;
783 }
784 
785 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
786 {
787         struct buffer_head * bh;
788         struct ext2_sb_info * sbi;
789         struct ext2_super_block * es;
790         struct inode *root;
791         unsigned long block;
792         unsigned long sb_block = get_sb_block(&data);
793         unsigned long logic_sb_block;
794         unsigned long offset = 0;
795         unsigned long def_mount_opts;
796         long ret = -EINVAL;
797         int blocksize = BLOCK_SIZE;
798         int db_count;
799         int i, j;
800         __le32 features;
801         int err;
802 
803         err = -ENOMEM;
804         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
805         if (!sbi)
806                 goto failed;
807 
808         sbi->s_blockgroup_lock =
809                 kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
810         if (!sbi->s_blockgroup_lock) {
811                 kfree(sbi);
812                 goto failed;
813         }
814         sb->s_fs_info = sbi;
815         sbi->s_sb_block = sb_block;
816 
817         spin_lock_init(&sbi->s_lock);
818 
819         /*
820          * See what the current blocksize for the device is, and
821          * use that as the blocksize.  Otherwise (or if the blocksize
822          * is smaller than the default) use the default.
823          * This is important for devices that have a hardware
824          * sectorsize that is larger than the default.
825          */
826         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
827         if (!blocksize) {
828                 ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
829                 goto failed_sbi;
830         }
831 
832         /*
833          * If the superblock doesn't start on a hardware sector boundary,
834          * calculate the offset.  
835          */
836         if (blocksize != BLOCK_SIZE) {
837                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
838                 offset = (sb_block*BLOCK_SIZE) % blocksize;
839         } else {
840                 logic_sb_block = sb_block;
841         }
842 
843         if (!(bh = sb_bread(sb, logic_sb_block))) {
844                 ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
845                 goto failed_sbi;
846         }
847         /*
848          * Note: s_es must be initialized as soon as possible because
849          *       some ext2 macro-instructions depend on its value
850          */
851         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
852         sbi->s_es = es;
853         sb->s_magic = le16_to_cpu(es->s_magic);
854 
855         if (sb->s_magic != EXT2_SUPER_MAGIC)
856                 goto cantfind_ext2;
857 
858         /* Set defaults before we parse the mount options */
859         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
860         if (def_mount_opts & EXT2_DEFM_DEBUG)
861                 set_opt(sbi->s_mount_opt, DEBUG);
862         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
863                 set_opt(sbi->s_mount_opt, GRPID);
864         if (def_mount_opts & EXT2_DEFM_UID16)
865                 set_opt(sbi->s_mount_opt, NO_UID32);
866 #ifdef CONFIG_EXT2_FS_XATTR
867         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
868                 set_opt(sbi->s_mount_opt, XATTR_USER);
869 #endif
870 #ifdef CONFIG_EXT2_FS_POSIX_ACL
871         if (def_mount_opts & EXT2_DEFM_ACL)
872                 set_opt(sbi->s_mount_opt, POSIX_ACL);
873 #endif
874         
875         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
876                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
877         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
878                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
879         else
880                 set_opt(sbi->s_mount_opt, ERRORS_RO);
881 
882         sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
883         sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
884         
885         set_opt(sbi->s_mount_opt, RESERVATION);
886 
887         if (!parse_options((char *) data, sb))
888                 goto failed_mount;
889 
890         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
891                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
892                  MS_POSIXACL : 0);
893         sb->s_iflags |= SB_I_CGROUPWB;
894 
895         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
896             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
897              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
898              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
899                 ext2_msg(sb, KERN_WARNING,
900                         "warning: feature flags set on rev 0 fs, "
901                         "running e2fsck is recommended");
902         /*
903          * Check feature flags regardless of the revision level, since we
904          * previously didn't change the revision level when setting the flags,
905          * so there is a chance incompat flags are set on a rev 0 filesystem.
906          */
907         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
908         if (features) {
909                 ext2_msg(sb, KERN_ERR,  "error: couldn't mount because of "
910                        "unsupported optional features (%x)",
911                         le32_to_cpu(features));
912                 goto failed_mount;
913         }
914         if (!(sb->s_flags & MS_RDONLY) &&
915             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
916                 ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
917                        "unsupported optional features (%x)",
918                        le32_to_cpu(features));
919                 goto failed_mount;
920         }
921 
922         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
923 
924         if (sbi->s_mount_opt & EXT2_MOUNT_DAX) {
925                 if (blocksize != PAGE_SIZE) {
926                         ext2_msg(sb, KERN_ERR,
927                                         "error: unsupported blocksize for dax");
928                         goto failed_mount;
929                 }
930                 if (!sb->s_bdev->bd_disk->fops->direct_access) {
931                         ext2_msg(sb, KERN_ERR,
932                                         "error: device does not support dax");
933                         goto failed_mount;
934                 }
935         }
936 
937         /* If the blocksize doesn't match, re-read the thing.. */
938         if (sb->s_blocksize != blocksize) {
939                 brelse(bh);
940 
941                 if (!sb_set_blocksize(sb, blocksize)) {
942                         ext2_msg(sb, KERN_ERR,
943                                 "error: bad blocksize %d", blocksize);
944                         goto failed_sbi;
945                 }
946 
947                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
948                 offset = (sb_block*BLOCK_SIZE) % blocksize;
949                 bh = sb_bread(sb, logic_sb_block);
950                 if(!bh) {
951                         ext2_msg(sb, KERN_ERR, "error: couldn't read"
952                                 "superblock on 2nd try");
953                         goto failed_sbi;
954                 }
955                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
956                 sbi->s_es = es;
957                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
958                         ext2_msg(sb, KERN_ERR, "error: magic mismatch");
959                         goto failed_mount;
960                 }
961         }
962 
963         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
964         sb->s_max_links = EXT2_LINK_MAX;
965 
966         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
967                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
968                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
969         } else {
970                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
971                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
972                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
973                     !is_power_of_2(sbi->s_inode_size) ||
974                     (sbi->s_inode_size > blocksize)) {
975                         ext2_msg(sb, KERN_ERR,
976                                 "error: unsupported inode size: %d",
977                                 sbi->s_inode_size);
978                         goto failed_mount;
979                 }
980         }
981 
982         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
983                                    le32_to_cpu(es->s_log_frag_size);
984         if (sbi->s_frag_size == 0)
985                 goto cantfind_ext2;
986         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
987 
988         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
989         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
990         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
991 
992         if (EXT2_INODE_SIZE(sb) == 0)
993                 goto cantfind_ext2;
994         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
995         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
996                 goto cantfind_ext2;
997         sbi->s_itb_per_group = sbi->s_inodes_per_group /
998                                         sbi->s_inodes_per_block;
999         sbi->s_desc_per_block = sb->s_blocksize /
1000                                         sizeof (struct ext2_group_desc);
1001         sbi->s_sbh = bh;
1002         sbi->s_mount_state = le16_to_cpu(es->s_state);
1003         sbi->s_addr_per_block_bits =
1004                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
1005         sbi->s_desc_per_block_bits =
1006                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
1007 
1008         if (sb->s_magic != EXT2_SUPER_MAGIC)
1009                 goto cantfind_ext2;
1010 
1011         if (sb->s_blocksize != bh->b_size) {
1012                 if (!silent)
1013                         ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
1014                 goto failed_mount;
1015         }
1016 
1017         if (sb->s_blocksize != sbi->s_frag_size) {
1018                 ext2_msg(sb, KERN_ERR,
1019                         "error: fragsize %lu != blocksize %lu"
1020                         "(not supported yet)",
1021                         sbi->s_frag_size, sb->s_blocksize);
1022                 goto failed_mount;
1023         }
1024 
1025         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
1026                 ext2_msg(sb, KERN_ERR,
1027                         "error: #blocks per group too big: %lu",
1028                         sbi->s_blocks_per_group);
1029                 goto failed_mount;
1030         }
1031         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
1032                 ext2_msg(sb, KERN_ERR,
1033                         "error: #fragments per group too big: %lu",
1034                         sbi->s_frags_per_group);
1035                 goto failed_mount;
1036         }
1037         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
1038                 ext2_msg(sb, KERN_ERR,
1039                         "error: #inodes per group too big: %lu",
1040                         sbi->s_inodes_per_group);
1041                 goto failed_mount;
1042         }
1043 
1044         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
1045                 goto cantfind_ext2;
1046         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
1047                                 le32_to_cpu(es->s_first_data_block) - 1)
1048                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
1049         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
1050                    EXT2_DESC_PER_BLOCK(sb);
1051         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
1052         if (sbi->s_group_desc == NULL) {
1053                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
1054                 goto failed_mount;
1055         }
1056         bgl_lock_init(sbi->s_blockgroup_lock);
1057         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1058         if (!sbi->s_debts) {
1059                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
1060                 goto failed_mount_group_desc;
1061         }
1062         for (i = 0; i < db_count; i++) {
1063                 block = descriptor_loc(sb, logic_sb_block, i);
1064                 sbi->s_group_desc[i] = sb_bread(sb, block);
1065                 if (!sbi->s_group_desc[i]) {
1066                         for (j = 0; j < i; j++)
1067                                 brelse (sbi->s_group_desc[j]);
1068                         ext2_msg(sb, KERN_ERR,
1069                                 "error: unable to read group descriptors");
1070                         goto failed_mount_group_desc;
1071                 }
1072         }
1073         if (!ext2_check_descriptors (sb)) {
1074                 ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1075                 goto failed_mount2;
1076         }
1077         sbi->s_gdb_count = db_count;
1078         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1079         spin_lock_init(&sbi->s_next_gen_lock);
1080 
1081         /* per fileystem reservation list head & lock */
1082         spin_lock_init(&sbi->s_rsv_window_lock);
1083         sbi->s_rsv_window_root = RB_ROOT;
1084         /*
1085          * Add a single, static dummy reservation to the start of the
1086          * reservation window list --- it gives us a placeholder for
1087          * append-at-start-of-list which makes the allocation logic
1088          * _much_ simpler.
1089          */
1090         sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1091         sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1092         sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1093         sbi->s_rsv_window_head.rsv_goal_size = 0;
1094         ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1095 
1096         err = percpu_counter_init(&sbi->s_freeblocks_counter,
1097                                 ext2_count_free_blocks(sb), GFP_KERNEL);
1098         if (!err) {
1099                 err = percpu_counter_init(&sbi->s_freeinodes_counter,
1100                                 ext2_count_free_inodes(sb), GFP_KERNEL);
1101         }
1102         if (!err) {
1103                 err = percpu_counter_init(&sbi->s_dirs_counter,
1104                                 ext2_count_dirs(sb), GFP_KERNEL);
1105         }
1106         if (err) {
1107                 ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1108                 goto failed_mount3;
1109         }
1110 
1111 #ifdef CONFIG_EXT2_FS_XATTR
1112         sbi->s_mb_cache = ext2_xattr_create_cache();
1113         if (!sbi->s_mb_cache) {
1114                 ext2_msg(sb, KERN_ERR, "Failed to create an mb_cache");
1115                 goto failed_mount3;
1116         }
1117 #endif
1118         /*
1119          * set up enough so that it can read an inode
1120          */
1121         sb->s_op = &ext2_sops;
1122         sb->s_export_op = &ext2_export_ops;
1123         sb->s_xattr = ext2_xattr_handlers;
1124 
1125 #ifdef CONFIG_QUOTA
1126         sb->dq_op = &dquot_operations;
1127         sb->s_qcop = &dquot_quotactl_ops;
1128         sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP;
1129 #endif
1130 
1131         root = ext2_iget(sb, EXT2_ROOT_INO);
1132         if (IS_ERR(root)) {
1133                 ret = PTR_ERR(root);
1134                 goto failed_mount3;
1135         }
1136         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1137                 iput(root);
1138                 ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1139                 goto failed_mount3;
1140         }
1141 
1142         sb->s_root = d_make_root(root);
1143         if (!sb->s_root) {
1144                 ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1145                 ret = -ENOMEM;
1146                 goto failed_mount3;
1147         }
1148         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1149                 ext2_msg(sb, KERN_WARNING,
1150                         "warning: mounting ext3 filesystem as ext2");
1151         if (ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY))
1152                 sb->s_flags |= MS_RDONLY;
1153         ext2_write_super(sb);
1154         return 0;
1155 
1156 cantfind_ext2:
1157         if (!silent)
1158                 ext2_msg(sb, KERN_ERR,
1159                         "error: can't find an ext2 filesystem on dev %s.",
1160                         sb->s_id);
1161         goto failed_mount;
1162 failed_mount3:
1163         if (sbi->s_mb_cache)
1164                 ext2_xattr_destroy_cache(sbi->s_mb_cache);
1165         percpu_counter_destroy(&sbi->s_freeblocks_counter);
1166         percpu_counter_destroy(&sbi->s_freeinodes_counter);
1167         percpu_counter_destroy(&sbi->s_dirs_counter);
1168 failed_mount2:
1169         for (i = 0; i < db_count; i++)
1170                 brelse(sbi->s_group_desc[i]);
1171 failed_mount_group_desc:
1172         kfree(sbi->s_group_desc);
1173         kfree(sbi->s_debts);
1174 failed_mount:
1175         brelse(bh);
1176 failed_sbi:
1177         sb->s_fs_info = NULL;
1178         kfree(sbi->s_blockgroup_lock);
1179         kfree(sbi);
1180 failed:
1181         return ret;
1182 }
1183 
1184 static void ext2_clear_super_error(struct super_block *sb)
1185 {
1186         struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1187 
1188         if (buffer_write_io_error(sbh)) {
1189                 /*
1190                  * Oh, dear.  A previous attempt to write the
1191                  * superblock failed.  This could happen because the
1192                  * USB device was yanked out.  Or it could happen to
1193                  * be a transient write error and maybe the block will
1194                  * be remapped.  Nothing we can do but to retry the
1195                  * write and hope for the best.
1196                  */
1197                 ext2_msg(sb, KERN_ERR,
1198                        "previous I/O error to superblock detected\n");
1199                 clear_buffer_write_io_error(sbh);
1200                 set_buffer_uptodate(sbh);
1201         }
1202 }
1203 
1204 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
1205                             int wait)
1206 {
1207         ext2_clear_super_error(sb);
1208         spin_lock(&EXT2_SB(sb)->s_lock);
1209         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1210         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1211         es->s_wtime = cpu_to_le32(get_seconds());
1212         /* unlock before we do IO */
1213         spin_unlock(&EXT2_SB(sb)->s_lock);
1214         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1215         if (wait)
1216                 sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1217 }
1218 
1219 /*
1220  * In the second extended file system, it is not necessary to
1221  * write the super block since we use a mapping of the
1222  * disk super block in a buffer.
1223  *
1224  * However, this function is still used to set the fs valid
1225  * flags to 0.  We need to set this flag to 0 since the fs
1226  * may have been checked while mounted and e2fsck may have
1227  * set s_state to EXT2_VALID_FS after some corrections.
1228  */
1229 static int ext2_sync_fs(struct super_block *sb, int wait)
1230 {
1231         struct ext2_sb_info *sbi = EXT2_SB(sb);
1232         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1233 
1234         /*
1235          * Write quota structures to quota file, sync_blockdev() will write
1236          * them to disk later
1237          */
1238         dquot_writeback_dquots(sb, -1);
1239 
1240         spin_lock(&sbi->s_lock);
1241         if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1242                 ext2_debug("setting valid to 0\n");
1243                 es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1244         }
1245         spin_unlock(&sbi->s_lock);
1246         ext2_sync_super(sb, es, wait);
1247         return 0;
1248 }
1249 
1250 static int ext2_freeze(struct super_block *sb)
1251 {
1252         struct ext2_sb_info *sbi = EXT2_SB(sb);
1253 
1254         /*
1255          * Open but unlinked files present? Keep EXT2_VALID_FS flag cleared
1256          * because we have unattached inodes and thus filesystem is not fully
1257          * consistent.
1258          */
1259         if (atomic_long_read(&sb->s_remove_count)) {
1260                 ext2_sync_fs(sb, 1);
1261                 return 0;
1262         }
1263         /* Set EXT2_FS_VALID flag */
1264         spin_lock(&sbi->s_lock);
1265         sbi->s_es->s_state = cpu_to_le16(sbi->s_mount_state);
1266         spin_unlock(&sbi->s_lock);
1267         ext2_sync_super(sb, sbi->s_es, 1);
1268 
1269         return 0;
1270 }
1271 
1272 static int ext2_unfreeze(struct super_block *sb)
1273 {
1274         /* Just write sb to clear EXT2_VALID_FS flag */
1275         ext2_write_super(sb);
1276 
1277         return 0;
1278 }
1279 
1280 void ext2_write_super(struct super_block *sb)
1281 {
1282         if (!(sb->s_flags & MS_RDONLY))
1283                 ext2_sync_fs(sb, 1);
1284 }
1285 
1286 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1287 {
1288         struct ext2_sb_info * sbi = EXT2_SB(sb);
1289         struct ext2_super_block * es;
1290         struct ext2_mount_options old_opts;
1291         unsigned long old_sb_flags;
1292         int err;
1293 
1294         sync_filesystem(sb);
1295         spin_lock(&sbi->s_lock);
1296 
1297         /* Store the old options */
1298         old_sb_flags = sb->s_flags;
1299         old_opts.s_mount_opt = sbi->s_mount_opt;
1300         old_opts.s_resuid = sbi->s_resuid;
1301         old_opts.s_resgid = sbi->s_resgid;
1302 
1303         /*
1304          * Allow the "check" option to be passed as a remount option.
1305          */
1306         if (!parse_options(data, sb)) {
1307                 err = -EINVAL;
1308                 goto restore_opts;
1309         }
1310 
1311         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1312                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1313 
1314         es = sbi->s_es;
1315         if ((sbi->s_mount_opt ^ old_opts.s_mount_opt) & EXT2_MOUNT_DAX) {
1316                 ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1317                          "dax flag with busy inodes while remounting");
1318                 sbi->s_mount_opt ^= EXT2_MOUNT_DAX;
1319         }
1320         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
1321                 spin_unlock(&sbi->s_lock);
1322                 return 0;
1323         }
1324         if (*flags & MS_RDONLY) {
1325                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1326                     !(sbi->s_mount_state & EXT2_VALID_FS)) {
1327                         spin_unlock(&sbi->s_lock);
1328                         return 0;
1329                 }
1330 
1331                 /*
1332                  * OK, we are remounting a valid rw partition rdonly, so set
1333                  * the rdonly flag and then mark the partition as valid again.
1334                  */
1335                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1336                 es->s_mtime = cpu_to_le32(get_seconds());
1337                 spin_unlock(&sbi->s_lock);
1338 
1339                 err = dquot_suspend(sb, -1);
1340                 if (err < 0) {
1341                         spin_lock(&sbi->s_lock);
1342                         goto restore_opts;
1343                 }
1344 
1345                 ext2_sync_super(sb, es, 1);
1346         } else {
1347                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1348                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1349                 if (ret) {
1350                         ext2_msg(sb, KERN_WARNING,
1351                                 "warning: couldn't remount RDWR because of "
1352                                 "unsupported optional features (%x).",
1353                                 le32_to_cpu(ret));
1354                         err = -EROFS;
1355                         goto restore_opts;
1356                 }
1357                 /*
1358                  * Mounting a RDONLY partition read-write, so reread and
1359                  * store the current valid flag.  (It may have been changed
1360                  * by e2fsck since we originally mounted the partition.)
1361                  */
1362                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1363                 if (!ext2_setup_super (sb, es, 0))
1364                         sb->s_flags &= ~MS_RDONLY;
1365                 spin_unlock(&sbi->s_lock);
1366 
1367                 ext2_write_super(sb);
1368 
1369                 dquot_resume(sb, -1);
1370         }
1371 
1372         return 0;
1373 restore_opts:
1374         sbi->s_mount_opt = old_opts.s_mount_opt;
1375         sbi->s_resuid = old_opts.s_resuid;
1376         sbi->s_resgid = old_opts.s_resgid;
1377         sb->s_flags = old_sb_flags;
1378         spin_unlock(&sbi->s_lock);
1379         return err;
1380 }
1381 
1382 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1383 {
1384         struct super_block *sb = dentry->d_sb;
1385         struct ext2_sb_info *sbi = EXT2_SB(sb);
1386         struct ext2_super_block *es = sbi->s_es;
1387         u64 fsid;
1388 
1389         spin_lock(&sbi->s_lock);
1390 
1391         if (test_opt (sb, MINIX_DF))
1392                 sbi->s_overhead_last = 0;
1393         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1394                 unsigned long i, overhead = 0;
1395                 smp_rmb();
1396 
1397                 /*
1398                  * Compute the overhead (FS structures). This is constant
1399                  * for a given filesystem unless the number of block groups
1400                  * changes so we cache the previous value until it does.
1401                  */
1402 
1403                 /*
1404                  * All of the blocks before first_data_block are
1405                  * overhead
1406                  */
1407                 overhead = le32_to_cpu(es->s_first_data_block);
1408 
1409                 /*
1410                  * Add the overhead attributed to the superblock and
1411                  * block group descriptors.  If the sparse superblocks
1412                  * feature is turned on, then not all groups have this.
1413                  */
1414                 for (i = 0; i < sbi->s_groups_count; i++)
1415                         overhead += ext2_bg_has_super(sb, i) +
1416                                 ext2_bg_num_gdb(sb, i);
1417 
1418                 /*
1419                  * Every block group has an inode bitmap, a block
1420                  * bitmap, and an inode table.
1421                  */
1422                 overhead += (sbi->s_groups_count *
1423                              (2 + sbi->s_itb_per_group));
1424                 sbi->s_overhead_last = overhead;
1425                 smp_wmb();
1426                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1427         }
1428 
1429         buf->f_type = EXT2_SUPER_MAGIC;
1430         buf->f_bsize = sb->s_blocksize;
1431         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1432         buf->f_bfree = ext2_count_free_blocks(sb);
1433         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1434         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1435         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1436                 buf->f_bavail = 0;
1437         buf->f_files = le32_to_cpu(es->s_inodes_count);
1438         buf->f_ffree = ext2_count_free_inodes(sb);
1439         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1440         buf->f_namelen = EXT2_NAME_LEN;
1441         fsid = le64_to_cpup((void *)es->s_uuid) ^
1442                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1443         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1444         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1445         spin_unlock(&sbi->s_lock);
1446         return 0;
1447 }
1448 
1449 static struct dentry *ext2_mount(struct file_system_type *fs_type,
1450         int flags, const char *dev_name, void *data)
1451 {
1452         return mount_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1453 }
1454 
1455 #ifdef CONFIG_QUOTA
1456 
1457 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1458  * acquiring the locks... As quota files are never truncated and quota code
1459  * itself serializes the operations (and no one else should touch the files)
1460  * we don't have to be afraid of races */
1461 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1462                                size_t len, loff_t off)
1463 {
1464         struct inode *inode = sb_dqopt(sb)->files[type];
1465         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1466         int err = 0;
1467         int offset = off & (sb->s_blocksize - 1);
1468         int tocopy;
1469         size_t toread;
1470         struct buffer_head tmp_bh;
1471         struct buffer_head *bh;
1472         loff_t i_size = i_size_read(inode);
1473 
1474         if (off > i_size)
1475                 return 0;
1476         if (off+len > i_size)
1477                 len = i_size-off;
1478         toread = len;
1479         while (toread > 0) {
1480                 tocopy = sb->s_blocksize - offset < toread ?
1481                                 sb->s_blocksize - offset : toread;
1482 
1483                 tmp_bh.b_state = 0;
1484                 tmp_bh.b_size = sb->s_blocksize;
1485                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1486                 if (err < 0)
1487                         return err;
1488                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1489                         memset(data, 0, tocopy);
1490                 else {
1491                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1492                         if (!bh)
1493                                 return -EIO;
1494                         memcpy(data, bh->b_data+offset, tocopy);
1495                         brelse(bh);
1496                 }
1497                 offset = 0;
1498                 toread -= tocopy;
1499                 data += tocopy;
1500                 blk++;
1501         }
1502         return len;
1503 }
1504 
1505 /* Write to quotafile */
1506 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1507                                 const char *data, size_t len, loff_t off)
1508 {
1509         struct inode *inode = sb_dqopt(sb)->files[type];
1510         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1511         int err = 0;
1512         int offset = off & (sb->s_blocksize - 1);
1513         int tocopy;
1514         size_t towrite = len;
1515         struct buffer_head tmp_bh;
1516         struct buffer_head *bh;
1517 
1518         while (towrite > 0) {
1519                 tocopy = sb->s_blocksize - offset < towrite ?
1520                                 sb->s_blocksize - offset : towrite;
1521 
1522                 tmp_bh.b_state = 0;
1523                 tmp_bh.b_size = sb->s_blocksize;
1524                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1525                 if (err < 0)
1526                         goto out;
1527                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1528                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1529                 else
1530                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1531                 if (unlikely(!bh)) {
1532                         err = -EIO;
1533                         goto out;
1534                 }
1535                 lock_buffer(bh);
1536                 memcpy(bh->b_data+offset, data, tocopy);
1537                 flush_dcache_page(bh->b_page);
1538                 set_buffer_uptodate(bh);
1539                 mark_buffer_dirty(bh);
1540                 unlock_buffer(bh);
1541                 brelse(bh);
1542                 offset = 0;
1543                 towrite -= tocopy;
1544                 data += tocopy;
1545                 blk++;
1546         }
1547 out:
1548         if (len == towrite)
1549                 return err;
1550         if (inode->i_size < off+len-towrite)
1551                 i_size_write(inode, off+len-towrite);
1552         inode->i_version++;
1553         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1554         mark_inode_dirty(inode);
1555         return len - towrite;
1556 }
1557 
1558 #endif
1559 
1560 static struct file_system_type ext2_fs_type = {
1561         .owner          = THIS_MODULE,
1562         .name           = "ext2",
1563         .mount          = ext2_mount,
1564         .kill_sb        = kill_block_super,
1565         .fs_flags       = FS_REQUIRES_DEV,
1566 };
1567 MODULE_ALIAS_FS("ext2");
1568 
1569 static int __init init_ext2_fs(void)
1570 {
1571         int err;
1572 
1573         err = init_inodecache();
1574         if (err)
1575                 return err;
1576         err = register_filesystem(&ext2_fs_type);
1577         if (err)
1578                 goto out;
1579         return 0;
1580 out:
1581         destroy_inodecache();
1582         return err;
1583 }
1584 
1585 static void __exit exit_ext2_fs(void)
1586 {
1587         unregister_filesystem(&ext2_fs_type);
1588         destroy_inodecache();
1589 }
1590 
1591 MODULE_AUTHOR("Remy Card and others");
1592 MODULE_DESCRIPTION("Second Extended Filesystem");
1593 MODULE_LICENSE("GPL");
1594 module_init(init_ext2_fs)
1595 module_exit(exit_ext2_fs)
1596 

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