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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 #include "xip.h"
 39 
 40 static void ext2_sync_super(struct super_block *sb,
 41                             struct ext2_super_block *es, int wait);
 42 static int ext2_remount (struct super_block * sb, int * flags, char * data);
 43 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
 44 static int ext2_sync_fs(struct super_block *sb, int wait);
 45 static int ext2_freeze(struct super_block *sb);
 46 static int ext2_unfreeze(struct super_block *sb);
 47 
 48 void ext2_error(struct super_block *sb, const char *function,
 49                 const char *fmt, ...)
 50 {
 51         struct va_format vaf;
 52         va_list args;
 53         struct ext2_sb_info *sbi = EXT2_SB(sb);
 54         struct ext2_super_block *es = sbi->s_es;
 55 
 56         if (!(sb->s_flags & MS_RDONLY)) {
 57                 spin_lock(&sbi->s_lock);
 58                 sbi->s_mount_state |= EXT2_ERROR_FS;
 59                 es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
 60                 spin_unlock(&sbi->s_lock);
 61                 ext2_sync_super(sb, es, 1);
 62         }
 63 
 64         va_start(args, fmt);
 65 
 66         vaf.fmt = fmt;
 67         vaf.va = &args;
 68 
 69         printk(KERN_CRIT "EXT2-fs (%s): error: %s: %pV\n",
 70                sb->s_id, function, &vaf);
 71 
 72         va_end(args);
 73 
 74         if (test_opt(sb, ERRORS_PANIC))
 75                 panic("EXT2-fs: panic from previous error\n");
 76         if (test_opt(sb, ERRORS_RO)) {
 77                 ext2_msg(sb, KERN_CRIT,
 78                              "error: remounting filesystem read-only");
 79                 sb->s_flags |= MS_RDONLY;
 80         }
 81 }
 82 
 83 void ext2_msg(struct super_block *sb, const char *prefix,
 84                 const char *fmt, ...)
 85 {
 86         struct va_format vaf;
 87         va_list args;
 88 
 89         va_start(args, fmt);
 90 
 91         vaf.fmt = fmt;
 92         vaf.va = &args;
 93 
 94         printk("%sEXT2-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
 95 
 96         va_end(args);
 97 }
 98 
 99 /*
100  * This must be called with sbi->s_lock held.
101  */
102 void ext2_update_dynamic_rev(struct super_block *sb)
103 {
104         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
105 
106         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
107                 return;
108 
109         ext2_msg(sb, KERN_WARNING,
110                      "warning: updating to rev %d because of "
111                      "new feature flag, running e2fsck is recommended",
112                      EXT2_DYNAMIC_REV);
113 
114         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
115         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
116         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
117         /* leave es->s_feature_*compat flags alone */
118         /* es->s_uuid will be set by e2fsck if empty */
119 
120         /*
121          * The rest of the superblock fields should be zero, and if not it
122          * means they are likely already in use, so leave them alone.  We
123          * can leave it up to e2fsck to clean up any inconsistencies there.
124          */
125 }
126 
127 static void ext2_put_super (struct super_block * sb)
128 {
129         int db_count;
130         int i;
131         struct ext2_sb_info *sbi = EXT2_SB(sb);
132 
133         dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
134 
135         ext2_xattr_put_super(sb);
136         if (!(sb->s_flags & MS_RDONLY)) {
137                 struct ext2_super_block *es = sbi->s_es;
138 
139                 spin_lock(&sbi->s_lock);
140                 es->s_state = cpu_to_le16(sbi->s_mount_state);
141                 spin_unlock(&sbi->s_lock);
142                 ext2_sync_super(sb, es, 1);
143         }
144         db_count = sbi->s_gdb_count;
145         for (i = 0; i < db_count; i++)
146                 if (sbi->s_group_desc[i])
147                         brelse (sbi->s_group_desc[i]);
148         kfree(sbi->s_group_desc);
149         kfree(sbi->s_debts);
150         percpu_counter_destroy(&sbi->s_freeblocks_counter);
151         percpu_counter_destroy(&sbi->s_freeinodes_counter);
152         percpu_counter_destroy(&sbi->s_dirs_counter);
153         brelse (sbi->s_sbh);
154         sb->s_fs_info = NULL;
155         kfree(sbi->s_blockgroup_lock);
156         kfree(sbi);
157 }
158 
159 static struct kmem_cache * ext2_inode_cachep;
160 
161 static struct inode *ext2_alloc_inode(struct super_block *sb)
162 {
163         struct ext2_inode_info *ei;
164         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
165         if (!ei)
166                 return NULL;
167         ei->i_block_alloc_info = NULL;
168         ei->vfs_inode.i_version = 1;
169         return &ei->vfs_inode;
170 }
171 
172 static void ext2_i_callback(struct rcu_head *head)
173 {
174         struct inode *inode = container_of(head, struct inode, i_rcu);
175         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
176 }
177 
178 static void ext2_destroy_inode(struct inode *inode)
179 {
180         call_rcu(&inode->i_rcu, ext2_i_callback);
181 }
182 
183 static void init_once(void *foo)
184 {
185         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
186 
187         rwlock_init(&ei->i_meta_lock);
188 #ifdef CONFIG_EXT2_FS_XATTR
189         init_rwsem(&ei->xattr_sem);
190 #endif
191         mutex_init(&ei->truncate_mutex);
192         inode_init_once(&ei->vfs_inode);
193 }
194 
195 static int init_inodecache(void)
196 {
197         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
198                                              sizeof(struct ext2_inode_info),
199                                              0, (SLAB_RECLAIM_ACCOUNT|
200                                                 SLAB_MEM_SPREAD),
201                                              init_once);
202         if (ext2_inode_cachep == NULL)
203                 return -ENOMEM;
204         return 0;
205 }
206 
207 static void destroy_inodecache(void)
208 {
209         /*
210          * Make sure all delayed rcu free inodes are flushed before we
211          * destroy cache.
212          */
213         rcu_barrier();
214         kmem_cache_destroy(ext2_inode_cachep);
215 }
216 
217 static int ext2_show_options(struct seq_file *seq, struct dentry *root)
218 {
219         struct super_block *sb = root->d_sb;
220         struct ext2_sb_info *sbi = EXT2_SB(sb);
221         struct ext2_super_block *es = sbi->s_es;
222         unsigned long def_mount_opts;
223 
224         spin_lock(&sbi->s_lock);
225         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
226 
227         if (sbi->s_sb_block != 1)
228                 seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
229         if (test_opt(sb, MINIX_DF))
230                 seq_puts(seq, ",minixdf");
231         if (test_opt(sb, GRPID))
232                 seq_puts(seq, ",grpid");
233         if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
234                 seq_puts(seq, ",nogrpid");
235         if (!uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT2_DEF_RESUID)) ||
236             le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
237                 seq_printf(seq, ",resuid=%u",
238                                 from_kuid_munged(&init_user_ns, sbi->s_resuid));
239         }
240         if (!gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT2_DEF_RESGID)) ||
241             le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
242                 seq_printf(seq, ",resgid=%u",
243                                 from_kgid_munged(&init_user_ns, sbi->s_resgid));
244         }
245         if (test_opt(sb, ERRORS_RO)) {
246                 int def_errors = le16_to_cpu(es->s_errors);
247 
248                 if (def_errors == EXT2_ERRORS_PANIC ||
249                     def_errors == EXT2_ERRORS_CONTINUE) {
250                         seq_puts(seq, ",errors=remount-ro");
251                 }
252         }
253         if (test_opt(sb, ERRORS_CONT))
254                 seq_puts(seq, ",errors=continue");
255         if (test_opt(sb, ERRORS_PANIC))
256                 seq_puts(seq, ",errors=panic");
257         if (test_opt(sb, NO_UID32))
258                 seq_puts(seq, ",nouid32");
259         if (test_opt(sb, DEBUG))
260                 seq_puts(seq, ",debug");
261         if (test_opt(sb, OLDALLOC))
262                 seq_puts(seq, ",oldalloc");
263 
264 #ifdef CONFIG_EXT2_FS_XATTR
265         if (test_opt(sb, XATTR_USER))
266                 seq_puts(seq, ",user_xattr");
267         if (!test_opt(sb, XATTR_USER) &&
268             (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
269                 seq_puts(seq, ",nouser_xattr");
270         }
271 #endif
272 
273 #ifdef CONFIG_EXT2_FS_POSIX_ACL
274         if (test_opt(sb, POSIX_ACL))
275                 seq_puts(seq, ",acl");
276         if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
277                 seq_puts(seq, ",noacl");
278 #endif
279 
280         if (test_opt(sb, NOBH))
281                 seq_puts(seq, ",nobh");
282 
283 #if defined(CONFIG_QUOTA)
284         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
285                 seq_puts(seq, ",usrquota");
286 
287         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
288                 seq_puts(seq, ",grpquota");
289 #endif
290 
291 #if defined(CONFIG_EXT2_FS_XIP)
292         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
293                 seq_puts(seq, ",xip");
294 #endif
295 
296         if (!test_opt(sb, RESERVATION))
297                 seq_puts(seq, ",noreservation");
298 
299         spin_unlock(&sbi->s_lock);
300         return 0;
301 }
302 
303 #ifdef CONFIG_QUOTA
304 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
305 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
306 #endif
307 
308 static const struct super_operations ext2_sops = {
309         .alloc_inode    = ext2_alloc_inode,
310         .destroy_inode  = ext2_destroy_inode,
311         .write_inode    = ext2_write_inode,
312         .evict_inode    = ext2_evict_inode,
313         .put_super      = ext2_put_super,
314         .sync_fs        = ext2_sync_fs,
315         .freeze_fs      = ext2_freeze,
316         .unfreeze_fs    = ext2_unfreeze,
317         .statfs         = ext2_statfs,
318         .remount_fs     = ext2_remount,
319         .show_options   = ext2_show_options,
320 #ifdef CONFIG_QUOTA
321         .quota_read     = ext2_quota_read,
322         .quota_write    = ext2_quota_write,
323 #endif
324 };
325 
326 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
327                 u64 ino, u32 generation)
328 {
329         struct inode *inode;
330 
331         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
332                 return ERR_PTR(-ESTALE);
333         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
334                 return ERR_PTR(-ESTALE);
335 
336         /*
337          * ext2_iget isn't quite right if the inode is currently unallocated!
338          * However ext2_iget currently does appropriate checks to handle stale
339          * inodes so everything is OK.
340          */
341         inode = ext2_iget(sb, ino);
342         if (IS_ERR(inode))
343                 return ERR_CAST(inode);
344         if (generation && inode->i_generation != generation) {
345                 /* we didn't find the right inode.. */
346                 iput(inode);
347                 return ERR_PTR(-ESTALE);
348         }
349         return inode;
350 }
351 
352 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
353                 int fh_len, int fh_type)
354 {
355         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
356                                     ext2_nfs_get_inode);
357 }
358 
359 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
360                 int fh_len, int fh_type)
361 {
362         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
363                                     ext2_nfs_get_inode);
364 }
365 
366 static const struct export_operations ext2_export_ops = {
367         .fh_to_dentry = ext2_fh_to_dentry,
368         .fh_to_parent = ext2_fh_to_parent,
369         .get_parent = ext2_get_parent,
370 };
371 
372 static unsigned long get_sb_block(void **data)
373 {
374         unsigned long   sb_block;
375         char            *options = (char *) *data;
376 
377         if (!options || strncmp(options, "sb=", 3) != 0)
378                 return 1;       /* Default location */
379         options += 3;
380         sb_block = simple_strtoul(options, &options, 0);
381         if (*options && *options != ',') {
382                 printk("EXT2-fs: Invalid sb specification: %s\n",
383                        (char *) *data);
384                 return 1;
385         }
386         if (*options == ',')
387                 options++;
388         *data = (void *) options;
389         return sb_block;
390 }
391 
392 enum {
393         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
394         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
395         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
396         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
397         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
398         Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
399 };
400 
401 static const match_table_t tokens = {
402         {Opt_bsd_df, "bsddf"},
403         {Opt_minix_df, "minixdf"},
404         {Opt_grpid, "grpid"},
405         {Opt_grpid, "bsdgroups"},
406         {Opt_nogrpid, "nogrpid"},
407         {Opt_nogrpid, "sysvgroups"},
408         {Opt_resgid, "resgid=%u"},
409         {Opt_resuid, "resuid=%u"},
410         {Opt_sb, "sb=%u"},
411         {Opt_err_cont, "errors=continue"},
412         {Opt_err_panic, "errors=panic"},
413         {Opt_err_ro, "errors=remount-ro"},
414         {Opt_nouid32, "nouid32"},
415         {Opt_nocheck, "check=none"},
416         {Opt_nocheck, "nocheck"},
417         {Opt_debug, "debug"},
418         {Opt_oldalloc, "oldalloc"},
419         {Opt_orlov, "orlov"},
420         {Opt_nobh, "nobh"},
421         {Opt_user_xattr, "user_xattr"},
422         {Opt_nouser_xattr, "nouser_xattr"},
423         {Opt_acl, "acl"},
424         {Opt_noacl, "noacl"},
425         {Opt_xip, "xip"},
426         {Opt_grpquota, "grpquota"},
427         {Opt_ignore, "noquota"},
428         {Opt_quota, "quota"},
429         {Opt_usrquota, "usrquota"},
430         {Opt_reservation, "reservation"},
431         {Opt_noreservation, "noreservation"},
432         {Opt_err, NULL}
433 };
434 
435 static int parse_options(char *options, struct super_block *sb)
436 {
437         char *p;
438         struct ext2_sb_info *sbi = EXT2_SB(sb);
439         substring_t args[MAX_OPT_ARGS];
440         int option;
441         kuid_t uid;
442         kgid_t gid;
443 
444         if (!options)
445                 return 1;
446 
447         while ((p = strsep (&options, ",")) != NULL) {
448                 int token;
449                 if (!*p)
450                         continue;
451 
452                 token = match_token(p, tokens, args);
453                 switch (token) {
454                 case Opt_bsd_df:
455                         clear_opt (sbi->s_mount_opt, MINIX_DF);
456                         break;
457                 case Opt_minix_df:
458                         set_opt (sbi->s_mount_opt, MINIX_DF);
459                         break;
460                 case Opt_grpid:
461                         set_opt (sbi->s_mount_opt, GRPID);
462                         break;
463                 case Opt_nogrpid:
464                         clear_opt (sbi->s_mount_opt, GRPID);
465                         break;
466                 case Opt_resuid:
467                         if (match_int(&args[0], &option))
468                                 return 0;
469                         uid = make_kuid(current_user_ns(), option);
470                         if (!uid_valid(uid)) {
471                                 ext2_msg(sb, KERN_ERR, "Invalid uid value %d", option);
472                                 return 0;
473 
474                         }
475                         sbi->s_resuid = uid;
476                         break;
477                 case Opt_resgid:
478                         if (match_int(&args[0], &option))
479                                 return 0;
480                         gid = make_kgid(current_user_ns(), option);
481                         if (!gid_valid(gid)) {
482                                 ext2_msg(sb, KERN_ERR, "Invalid gid value %d", option);
483                                 return 0;
484                         }
485                         sbi->s_resgid = gid;
486                         break;
487                 case Opt_sb:
488                         /* handled by get_sb_block() instead of here */
489                         /* *sb_block = match_int(&args[0]); */
490                         break;
491                 case Opt_err_panic:
492                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
493                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
494                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
495                         break;
496                 case Opt_err_ro:
497                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
498                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
499                         set_opt (sbi->s_mount_opt, ERRORS_RO);
500                         break;
501                 case Opt_err_cont:
502                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
503                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
504                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
505                         break;
506                 case Opt_nouid32:
507                         set_opt (sbi->s_mount_opt, NO_UID32);
508                         break;
509                 case Opt_nocheck:
510                         clear_opt (sbi->s_mount_opt, CHECK);
511                         break;
512                 case Opt_debug:
513                         set_opt (sbi->s_mount_opt, DEBUG);
514                         break;
515                 case Opt_oldalloc:
516                         set_opt (sbi->s_mount_opt, OLDALLOC);
517                         break;
518                 case Opt_orlov:
519                         clear_opt (sbi->s_mount_opt, OLDALLOC);
520                         break;
521                 case Opt_nobh:
522                         set_opt (sbi->s_mount_opt, NOBH);
523                         break;
524 #ifdef CONFIG_EXT2_FS_XATTR
525                 case Opt_user_xattr:
526                         set_opt (sbi->s_mount_opt, XATTR_USER);
527                         break;
528                 case Opt_nouser_xattr:
529                         clear_opt (sbi->s_mount_opt, XATTR_USER);
530                         break;
531 #else
532                 case Opt_user_xattr:
533                 case Opt_nouser_xattr:
534                         ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
535                                 "not supported");
536                         break;
537 #endif
538 #ifdef CONFIG_EXT2_FS_POSIX_ACL
539                 case Opt_acl:
540                         set_opt(sbi->s_mount_opt, POSIX_ACL);
541                         break;
542                 case Opt_noacl:
543                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
544                         break;
545 #else
546                 case Opt_acl:
547                 case Opt_noacl:
548                         ext2_msg(sb, KERN_INFO,
549                                 "(no)acl options not supported");
550                         break;
551 #endif
552                 case Opt_xip:
553 #ifdef CONFIG_EXT2_FS_XIP
554                         set_opt (sbi->s_mount_opt, XIP);
555 #else
556                         ext2_msg(sb, KERN_INFO, "xip option not supported");
557 #endif
558                         break;
559 
560 #if defined(CONFIG_QUOTA)
561                 case Opt_quota:
562                 case Opt_usrquota:
563                         set_opt(sbi->s_mount_opt, USRQUOTA);
564                         break;
565 
566                 case Opt_grpquota:
567                         set_opt(sbi->s_mount_opt, GRPQUOTA);
568                         break;
569 #else
570                 case Opt_quota:
571                 case Opt_usrquota:
572                 case Opt_grpquota:
573                         ext2_msg(sb, KERN_INFO,
574                                 "quota operations not supported");
575                         break;
576 #endif
577 
578                 case Opt_reservation:
579                         set_opt(sbi->s_mount_opt, RESERVATION);
580                         ext2_msg(sb, KERN_INFO, "reservations ON");
581                         break;
582                 case Opt_noreservation:
583                         clear_opt(sbi->s_mount_opt, RESERVATION);
584                         ext2_msg(sb, KERN_INFO, "reservations OFF");
585                         break;
586                 case Opt_ignore:
587                         break;
588                 default:
589                         return 0;
590                 }
591         }
592         return 1;
593 }
594 
595 static int ext2_setup_super (struct super_block * sb,
596                               struct ext2_super_block * es,
597                               int read_only)
598 {
599         int res = 0;
600         struct ext2_sb_info *sbi = EXT2_SB(sb);
601 
602         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
603                 ext2_msg(sb, KERN_ERR,
604                         "error: revision level too high, "
605                         "forcing read-only mode");
606                 res = MS_RDONLY;
607         }
608         if (read_only)
609                 return res;
610         if (!(sbi->s_mount_state & EXT2_VALID_FS))
611                 ext2_msg(sb, KERN_WARNING,
612                         "warning: mounting unchecked fs, "
613                         "running e2fsck is recommended");
614         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
615                 ext2_msg(sb, KERN_WARNING,
616                         "warning: mounting fs with errors, "
617                         "running e2fsck is recommended");
618         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
619                  le16_to_cpu(es->s_mnt_count) >=
620                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
621                 ext2_msg(sb, KERN_WARNING,
622                         "warning: maximal mount count reached, "
623                         "running e2fsck is recommended");
624         else if (le32_to_cpu(es->s_checkinterval) &&
625                 (le32_to_cpu(es->s_lastcheck) +
626                         le32_to_cpu(es->s_checkinterval) <= get_seconds()))
627                 ext2_msg(sb, KERN_WARNING,
628                         "warning: checktime reached, "
629                         "running e2fsck is recommended");
630         if (!le16_to_cpu(es->s_max_mnt_count))
631                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
632         le16_add_cpu(&es->s_mnt_count, 1);
633         if (test_opt (sb, DEBUG))
634                 ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
635                         "bpg=%lu, ipg=%lu, mo=%04lx]",
636                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
637                         sbi->s_frag_size,
638                         sbi->s_groups_count,
639                         EXT2_BLOCKS_PER_GROUP(sb),
640                         EXT2_INODES_PER_GROUP(sb),
641                         sbi->s_mount_opt);
642         return res;
643 }
644 
645 static int ext2_check_descriptors(struct super_block *sb)
646 {
647         int i;
648         struct ext2_sb_info *sbi = EXT2_SB(sb);
649 
650         ext2_debug ("Checking group descriptors");
651 
652         for (i = 0; i < sbi->s_groups_count; i++) {
653                 struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
654                 ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
655                 ext2_fsblk_t last_block;
656 
657                 if (i == sbi->s_groups_count - 1)
658                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
659                 else
660                         last_block = first_block +
661                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
662 
663                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
664                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
665                 {
666                         ext2_error (sb, "ext2_check_descriptors",
667                                     "Block bitmap for group %d"
668                                     " not in group (block %lu)!",
669                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
670                         return 0;
671                 }
672                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
673                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
674                 {
675                         ext2_error (sb, "ext2_check_descriptors",
676                                     "Inode bitmap for group %d"
677                                     " not in group (block %lu)!",
678                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
679                         return 0;
680                 }
681                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
682                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
683                     last_block)
684                 {
685                         ext2_error (sb, "ext2_check_descriptors",
686                                     "Inode table for group %d"
687                                     " not in group (block %lu)!",
688                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
689                         return 0;
690                 }
691         }
692         return 1;
693 }
694 
695 /*
696  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
697  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
698  * We need to be 1 filesystem block less than the 2^32 sector limit.
699  */
700 static loff_t ext2_max_size(int bits)
701 {
702         loff_t res = EXT2_NDIR_BLOCKS;
703         int meta_blocks;
704         loff_t upper_limit;
705 
706         /* This is calculated to be the largest file size for a
707          * dense, file such that the total number of
708          * sectors in the file, including data and all indirect blocks,
709          * does not exceed 2^32 -1
710          * __u32 i_blocks representing the total number of
711          * 512 bytes blocks of the file
712          */
713         upper_limit = (1LL << 32) - 1;
714 
715         /* total blocks in file system block size */
716         upper_limit >>= (bits - 9);
717 
718 
719         /* indirect blocks */
720         meta_blocks = 1;
721         /* double indirect blocks */
722         meta_blocks += 1 + (1LL << (bits-2));
723         /* tripple indirect blocks */
724         meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
725 
726         upper_limit -= meta_blocks;
727         upper_limit <<= bits;
728 
729         res += 1LL << (bits-2);
730         res += 1LL << (2*(bits-2));
731         res += 1LL << (3*(bits-2));
732         res <<= bits;
733         if (res > upper_limit)
734                 res = upper_limit;
735 
736         if (res > MAX_LFS_FILESIZE)
737                 res = MAX_LFS_FILESIZE;
738 
739         return res;
740 }
741 
742 static unsigned long descriptor_loc(struct super_block *sb,
743                                     unsigned long logic_sb_block,
744                                     int nr)
745 {
746         struct ext2_sb_info *sbi = EXT2_SB(sb);
747         unsigned long bg, first_meta_bg;
748         int has_super = 0;
749         
750         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
751 
752         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
753             nr < first_meta_bg)
754                 return (logic_sb_block + nr + 1);
755         bg = sbi->s_desc_per_block * nr;
756         if (ext2_bg_has_super(sb, bg))
757                 has_super = 1;
758 
759         return ext2_group_first_block_no(sb, bg) + has_super;
760 }
761 
762 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
763 {
764         struct buffer_head * bh;
765         struct ext2_sb_info * sbi;
766         struct ext2_super_block * es;
767         struct inode *root;
768         unsigned long block;
769         unsigned long sb_block = get_sb_block(&data);
770         unsigned long logic_sb_block;
771         unsigned long offset = 0;
772         unsigned long def_mount_opts;
773         long ret = -EINVAL;
774         int blocksize = BLOCK_SIZE;
775         int db_count;
776         int i, j;
777         __le32 features;
778         int err;
779 
780         err = -ENOMEM;
781         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
782         if (!sbi)
783                 goto failed;
784 
785         sbi->s_blockgroup_lock =
786                 kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
787         if (!sbi->s_blockgroup_lock) {
788                 kfree(sbi);
789                 goto failed;
790         }
791         sb->s_fs_info = sbi;
792         sbi->s_sb_block = sb_block;
793 
794         spin_lock_init(&sbi->s_lock);
795 
796         /*
797          * See what the current blocksize for the device is, and
798          * use that as the blocksize.  Otherwise (or if the blocksize
799          * is smaller than the default) use the default.
800          * This is important for devices that have a hardware
801          * sectorsize that is larger than the default.
802          */
803         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
804         if (!blocksize) {
805                 ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
806                 goto failed_sbi;
807         }
808 
809         /*
810          * If the superblock doesn't start on a hardware sector boundary,
811          * calculate the offset.  
812          */
813         if (blocksize != BLOCK_SIZE) {
814                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
815                 offset = (sb_block*BLOCK_SIZE) % blocksize;
816         } else {
817                 logic_sb_block = sb_block;
818         }
819 
820         if (!(bh = sb_bread(sb, logic_sb_block))) {
821                 ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
822                 goto failed_sbi;
823         }
824         /*
825          * Note: s_es must be initialized as soon as possible because
826          *       some ext2 macro-instructions depend on its value
827          */
828         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
829         sbi->s_es = es;
830         sb->s_magic = le16_to_cpu(es->s_magic);
831 
832         if (sb->s_magic != EXT2_SUPER_MAGIC)
833                 goto cantfind_ext2;
834 
835         /* Set defaults before we parse the mount options */
836         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
837         if (def_mount_opts & EXT2_DEFM_DEBUG)
838                 set_opt(sbi->s_mount_opt, DEBUG);
839         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
840                 set_opt(sbi->s_mount_opt, GRPID);
841         if (def_mount_opts & EXT2_DEFM_UID16)
842                 set_opt(sbi->s_mount_opt, NO_UID32);
843 #ifdef CONFIG_EXT2_FS_XATTR
844         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
845                 set_opt(sbi->s_mount_opt, XATTR_USER);
846 #endif
847 #ifdef CONFIG_EXT2_FS_POSIX_ACL
848         if (def_mount_opts & EXT2_DEFM_ACL)
849                 set_opt(sbi->s_mount_opt, POSIX_ACL);
850 #endif
851         
852         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
853                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
854         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
855                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
856         else
857                 set_opt(sbi->s_mount_opt, ERRORS_RO);
858 
859         sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
860         sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
861         
862         set_opt(sbi->s_mount_opt, RESERVATION);
863 
864         if (!parse_options((char *) data, sb))
865                 goto failed_mount;
866 
867         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
868                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
869                  MS_POSIXACL : 0);
870 
871         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
872                                     EXT2_MOUNT_XIP if not */
873 
874         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
875             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
876              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
877              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
878                 ext2_msg(sb, KERN_WARNING,
879                         "warning: feature flags set on rev 0 fs, "
880                         "running e2fsck is recommended");
881         /*
882          * Check feature flags regardless of the revision level, since we
883          * previously didn't change the revision level when setting the flags,
884          * so there is a chance incompat flags are set on a rev 0 filesystem.
885          */
886         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
887         if (features) {
888                 ext2_msg(sb, KERN_ERR,  "error: couldn't mount because of "
889                        "unsupported optional features (%x)",
890                         le32_to_cpu(features));
891                 goto failed_mount;
892         }
893         if (!(sb->s_flags & MS_RDONLY) &&
894             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
895                 ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
896                        "unsupported optional features (%x)",
897                        le32_to_cpu(features));
898                 goto failed_mount;
899         }
900 
901         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
902 
903         if (ext2_use_xip(sb) && blocksize != PAGE_SIZE) {
904                 if (!silent)
905                         ext2_msg(sb, KERN_ERR,
906                                 "error: unsupported blocksize for xip");
907                 goto failed_mount;
908         }
909 
910         /* If the blocksize doesn't match, re-read the thing.. */
911         if (sb->s_blocksize != blocksize) {
912                 brelse(bh);
913 
914                 if (!sb_set_blocksize(sb, blocksize)) {
915                         ext2_msg(sb, KERN_ERR,
916                                 "error: bad blocksize %d", blocksize);
917                         goto failed_sbi;
918                 }
919 
920                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
921                 offset = (sb_block*BLOCK_SIZE) % blocksize;
922                 bh = sb_bread(sb, logic_sb_block);
923                 if(!bh) {
924                         ext2_msg(sb, KERN_ERR, "error: couldn't read"
925                                 "superblock on 2nd try");
926                         goto failed_sbi;
927                 }
928                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
929                 sbi->s_es = es;
930                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
931                         ext2_msg(sb, KERN_ERR, "error: magic mismatch");
932                         goto failed_mount;
933                 }
934         }
935 
936         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
937         sb->s_max_links = EXT2_LINK_MAX;
938 
939         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
940                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
941                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
942         } else {
943                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
944                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
945                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
946                     !is_power_of_2(sbi->s_inode_size) ||
947                     (sbi->s_inode_size > blocksize)) {
948                         ext2_msg(sb, KERN_ERR,
949                                 "error: unsupported inode size: %d",
950                                 sbi->s_inode_size);
951                         goto failed_mount;
952                 }
953         }
954 
955         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
956                                    le32_to_cpu(es->s_log_frag_size);
957         if (sbi->s_frag_size == 0)
958                 goto cantfind_ext2;
959         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
960 
961         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
962         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
963         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
964 
965         if (EXT2_INODE_SIZE(sb) == 0)
966                 goto cantfind_ext2;
967         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
968         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
969                 goto cantfind_ext2;
970         sbi->s_itb_per_group = sbi->s_inodes_per_group /
971                                         sbi->s_inodes_per_block;
972         sbi->s_desc_per_block = sb->s_blocksize /
973                                         sizeof (struct ext2_group_desc);
974         sbi->s_sbh = bh;
975         sbi->s_mount_state = le16_to_cpu(es->s_state);
976         sbi->s_addr_per_block_bits =
977                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
978         sbi->s_desc_per_block_bits =
979                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
980 
981         if (sb->s_magic != EXT2_SUPER_MAGIC)
982                 goto cantfind_ext2;
983 
984         if (sb->s_blocksize != bh->b_size) {
985                 if (!silent)
986                         ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
987                 goto failed_mount;
988         }
989 
990         if (sb->s_blocksize != sbi->s_frag_size) {
991                 ext2_msg(sb, KERN_ERR,
992                         "error: fragsize %lu != blocksize %lu"
993                         "(not supported yet)",
994                         sbi->s_frag_size, sb->s_blocksize);
995                 goto failed_mount;
996         }
997 
998         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
999                 ext2_msg(sb, KERN_ERR,
1000                         "error: #blocks per group too big: %lu",
1001                         sbi->s_blocks_per_group);
1002                 goto failed_mount;
1003         }
1004         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
1005                 ext2_msg(sb, KERN_ERR,
1006                         "error: #fragments per group too big: %lu",
1007                         sbi->s_frags_per_group);
1008                 goto failed_mount;
1009         }
1010         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
1011                 ext2_msg(sb, KERN_ERR,
1012                         "error: #inodes per group too big: %lu",
1013                         sbi->s_inodes_per_group);
1014                 goto failed_mount;
1015         }
1016 
1017         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
1018                 goto cantfind_ext2;
1019         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
1020                                 le32_to_cpu(es->s_first_data_block) - 1)
1021                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
1022         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
1023                    EXT2_DESC_PER_BLOCK(sb);
1024         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
1025         if (sbi->s_group_desc == NULL) {
1026                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
1027                 goto failed_mount;
1028         }
1029         bgl_lock_init(sbi->s_blockgroup_lock);
1030         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1031         if (!sbi->s_debts) {
1032                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
1033                 goto failed_mount_group_desc;
1034         }
1035         for (i = 0; i < db_count; i++) {
1036                 block = descriptor_loc(sb, logic_sb_block, i);
1037                 sbi->s_group_desc[i] = sb_bread(sb, block);
1038                 if (!sbi->s_group_desc[i]) {
1039                         for (j = 0; j < i; j++)
1040                                 brelse (sbi->s_group_desc[j]);
1041                         ext2_msg(sb, KERN_ERR,
1042                                 "error: unable to read group descriptors");
1043                         goto failed_mount_group_desc;
1044                 }
1045         }
1046         if (!ext2_check_descriptors (sb)) {
1047                 ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1048                 goto failed_mount2;
1049         }
1050         sbi->s_gdb_count = db_count;
1051         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1052         spin_lock_init(&sbi->s_next_gen_lock);
1053 
1054         /* per fileystem reservation list head & lock */
1055         spin_lock_init(&sbi->s_rsv_window_lock);
1056         sbi->s_rsv_window_root = RB_ROOT;
1057         /*
1058          * Add a single, static dummy reservation to the start of the
1059          * reservation window list --- it gives us a placeholder for
1060          * append-at-start-of-list which makes the allocation logic
1061          * _much_ simpler.
1062          */
1063         sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1064         sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1065         sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1066         sbi->s_rsv_window_head.rsv_goal_size = 0;
1067         ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1068 
1069         err = percpu_counter_init(&sbi->s_freeblocks_counter,
1070                                 ext2_count_free_blocks(sb));
1071         if (!err) {
1072                 err = percpu_counter_init(&sbi->s_freeinodes_counter,
1073                                 ext2_count_free_inodes(sb));
1074         }
1075         if (!err) {
1076                 err = percpu_counter_init(&sbi->s_dirs_counter,
1077                                 ext2_count_dirs(sb));
1078         }
1079         if (err) {
1080                 ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1081                 goto failed_mount3;
1082         }
1083         /*
1084          * set up enough so that it can read an inode
1085          */
1086         sb->s_op = &ext2_sops;
1087         sb->s_export_op = &ext2_export_ops;
1088         sb->s_xattr = ext2_xattr_handlers;
1089 
1090 #ifdef CONFIG_QUOTA
1091         sb->dq_op = &dquot_operations;
1092         sb->s_qcop = &dquot_quotactl_ops;
1093 #endif
1094 
1095         root = ext2_iget(sb, EXT2_ROOT_INO);
1096         if (IS_ERR(root)) {
1097                 ret = PTR_ERR(root);
1098                 goto failed_mount3;
1099         }
1100         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1101                 iput(root);
1102                 ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1103                 goto failed_mount3;
1104         }
1105 
1106         sb->s_root = d_make_root(root);
1107         if (!sb->s_root) {
1108                 ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1109                 ret = -ENOMEM;
1110                 goto failed_mount3;
1111         }
1112         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1113                 ext2_msg(sb, KERN_WARNING,
1114                         "warning: mounting ext3 filesystem as ext2");
1115         if (ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY))
1116                 sb->s_flags |= MS_RDONLY;
1117         ext2_write_super(sb);
1118         return 0;
1119 
1120 cantfind_ext2:
1121         if (!silent)
1122                 ext2_msg(sb, KERN_ERR,
1123                         "error: can't find an ext2 filesystem on dev %s.",
1124                         sb->s_id);
1125         goto failed_mount;
1126 failed_mount3:
1127         percpu_counter_destroy(&sbi->s_freeblocks_counter);
1128         percpu_counter_destroy(&sbi->s_freeinodes_counter);
1129         percpu_counter_destroy(&sbi->s_dirs_counter);
1130 failed_mount2:
1131         for (i = 0; i < db_count; i++)
1132                 brelse(sbi->s_group_desc[i]);
1133 failed_mount_group_desc:
1134         kfree(sbi->s_group_desc);
1135         kfree(sbi->s_debts);
1136 failed_mount:
1137         brelse(bh);
1138 failed_sbi:
1139         sb->s_fs_info = NULL;
1140         kfree(sbi->s_blockgroup_lock);
1141         kfree(sbi);
1142 failed:
1143         return ret;
1144 }
1145 
1146 static void ext2_clear_super_error(struct super_block *sb)
1147 {
1148         struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1149 
1150         if (buffer_write_io_error(sbh)) {
1151                 /*
1152                  * Oh, dear.  A previous attempt to write the
1153                  * superblock failed.  This could happen because the
1154                  * USB device was yanked out.  Or it could happen to
1155                  * be a transient write error and maybe the block will
1156                  * be remapped.  Nothing we can do but to retry the
1157                  * write and hope for the best.
1158                  */
1159                 ext2_msg(sb, KERN_ERR,
1160                        "previous I/O error to superblock detected\n");
1161                 clear_buffer_write_io_error(sbh);
1162                 set_buffer_uptodate(sbh);
1163         }
1164 }
1165 
1166 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
1167                             int wait)
1168 {
1169         ext2_clear_super_error(sb);
1170         spin_lock(&EXT2_SB(sb)->s_lock);
1171         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1172         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1173         es->s_wtime = cpu_to_le32(get_seconds());
1174         /* unlock before we do IO */
1175         spin_unlock(&EXT2_SB(sb)->s_lock);
1176         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1177         if (wait)
1178                 sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1179 }
1180 
1181 /*
1182  * In the second extended file system, it is not necessary to
1183  * write the super block since we use a mapping of the
1184  * disk super block in a buffer.
1185  *
1186  * However, this function is still used to set the fs valid
1187  * flags to 0.  We need to set this flag to 0 since the fs
1188  * may have been checked while mounted and e2fsck may have
1189  * set s_state to EXT2_VALID_FS after some corrections.
1190  */
1191 static int ext2_sync_fs(struct super_block *sb, int wait)
1192 {
1193         struct ext2_sb_info *sbi = EXT2_SB(sb);
1194         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1195 
1196         /*
1197          * Write quota structures to quota file, sync_blockdev() will write
1198          * them to disk later
1199          */
1200         dquot_writeback_dquots(sb, -1);
1201 
1202         spin_lock(&sbi->s_lock);
1203         if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1204                 ext2_debug("setting valid to 0\n");
1205                 es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1206         }
1207         spin_unlock(&sbi->s_lock);
1208         ext2_sync_super(sb, es, wait);
1209         return 0;
1210 }
1211 
1212 static int ext2_freeze(struct super_block *sb)
1213 {
1214         struct ext2_sb_info *sbi = EXT2_SB(sb);
1215 
1216         /*
1217          * Open but unlinked files present? Keep EXT2_VALID_FS flag cleared
1218          * because we have unattached inodes and thus filesystem is not fully
1219          * consistent.
1220          */
1221         if (atomic_long_read(&sb->s_remove_count)) {
1222                 ext2_sync_fs(sb, 1);
1223                 return 0;
1224         }
1225         /* Set EXT2_FS_VALID flag */
1226         spin_lock(&sbi->s_lock);
1227         sbi->s_es->s_state = cpu_to_le16(sbi->s_mount_state);
1228         spin_unlock(&sbi->s_lock);
1229         ext2_sync_super(sb, sbi->s_es, 1);
1230 
1231         return 0;
1232 }
1233 
1234 static int ext2_unfreeze(struct super_block *sb)
1235 {
1236         /* Just write sb to clear EXT2_VALID_FS flag */
1237         ext2_write_super(sb);
1238 
1239         return 0;
1240 }
1241 
1242 void ext2_write_super(struct super_block *sb)
1243 {
1244         if (!(sb->s_flags & MS_RDONLY))
1245                 ext2_sync_fs(sb, 1);
1246 }
1247 
1248 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1249 {
1250         struct ext2_sb_info * sbi = EXT2_SB(sb);
1251         struct ext2_super_block * es;
1252         unsigned long old_mount_opt = sbi->s_mount_opt;
1253         struct ext2_mount_options old_opts;
1254         unsigned long old_sb_flags;
1255         int err;
1256 
1257         spin_lock(&sbi->s_lock);
1258 
1259         /* Store the old options */
1260         old_sb_flags = sb->s_flags;
1261         old_opts.s_mount_opt = sbi->s_mount_opt;
1262         old_opts.s_resuid = sbi->s_resuid;
1263         old_opts.s_resgid = sbi->s_resgid;
1264 
1265         /*
1266          * Allow the "check" option to be passed as a remount option.
1267          */
1268         if (!parse_options(data, sb)) {
1269                 err = -EINVAL;
1270                 goto restore_opts;
1271         }
1272 
1273         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1274                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1275 
1276         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1277                                     EXT2_MOUNT_XIP if not */
1278 
1279         if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1280                 ext2_msg(sb, KERN_WARNING,
1281                         "warning: unsupported blocksize for xip");
1282                 err = -EINVAL;
1283                 goto restore_opts;
1284         }
1285 
1286         es = sbi->s_es;
1287         if ((sbi->s_mount_opt ^ old_mount_opt) & EXT2_MOUNT_XIP) {
1288                 ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1289                          "xip flag with busy inodes while remounting");
1290                 sbi->s_mount_opt &= ~EXT2_MOUNT_XIP;
1291                 sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;
1292         }
1293         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
1294                 spin_unlock(&sbi->s_lock);
1295                 return 0;
1296         }
1297         if (*flags & MS_RDONLY) {
1298                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1299                     !(sbi->s_mount_state & EXT2_VALID_FS)) {
1300                         spin_unlock(&sbi->s_lock);
1301                         return 0;
1302                 }
1303 
1304                 /*
1305                  * OK, we are remounting a valid rw partition rdonly, so set
1306                  * the rdonly flag and then mark the partition as valid again.
1307                  */
1308                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1309                 es->s_mtime = cpu_to_le32(get_seconds());
1310                 spin_unlock(&sbi->s_lock);
1311 
1312                 err = dquot_suspend(sb, -1);
1313                 if (err < 0) {
1314                         spin_lock(&sbi->s_lock);
1315                         goto restore_opts;
1316                 }
1317 
1318                 ext2_sync_super(sb, es, 1);
1319         } else {
1320                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1321                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1322                 if (ret) {
1323                         ext2_msg(sb, KERN_WARNING,
1324                                 "warning: couldn't remount RDWR because of "
1325                                 "unsupported optional features (%x).",
1326                                 le32_to_cpu(ret));
1327                         err = -EROFS;
1328                         goto restore_opts;
1329                 }
1330                 /*
1331                  * Mounting a RDONLY partition read-write, so reread and
1332                  * store the current valid flag.  (It may have been changed
1333                  * by e2fsck since we originally mounted the partition.)
1334                  */
1335                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1336                 if (!ext2_setup_super (sb, es, 0))
1337                         sb->s_flags &= ~MS_RDONLY;
1338                 spin_unlock(&sbi->s_lock);
1339 
1340                 ext2_write_super(sb);
1341 
1342                 dquot_resume(sb, -1);
1343         }
1344 
1345         return 0;
1346 restore_opts:
1347         sbi->s_mount_opt = old_opts.s_mount_opt;
1348         sbi->s_resuid = old_opts.s_resuid;
1349         sbi->s_resgid = old_opts.s_resgid;
1350         sb->s_flags = old_sb_flags;
1351         spin_unlock(&sbi->s_lock);
1352         return err;
1353 }
1354 
1355 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1356 {
1357         struct super_block *sb = dentry->d_sb;
1358         struct ext2_sb_info *sbi = EXT2_SB(sb);
1359         struct ext2_super_block *es = sbi->s_es;
1360         u64 fsid;
1361 
1362         spin_lock(&sbi->s_lock);
1363 
1364         if (test_opt (sb, MINIX_DF))
1365                 sbi->s_overhead_last = 0;
1366         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1367                 unsigned long i, overhead = 0;
1368                 smp_rmb();
1369 
1370                 /*
1371                  * Compute the overhead (FS structures). This is constant
1372                  * for a given filesystem unless the number of block groups
1373                  * changes so we cache the previous value until it does.
1374                  */
1375 
1376                 /*
1377                  * All of the blocks before first_data_block are
1378                  * overhead
1379                  */
1380                 overhead = le32_to_cpu(es->s_first_data_block);
1381 
1382                 /*
1383                  * Add the overhead attributed to the superblock and
1384                  * block group descriptors.  If the sparse superblocks
1385                  * feature is turned on, then not all groups have this.
1386                  */
1387                 for (i = 0; i < sbi->s_groups_count; i++)
1388                         overhead += ext2_bg_has_super(sb, i) +
1389                                 ext2_bg_num_gdb(sb, i);
1390 
1391                 /*
1392                  * Every block group has an inode bitmap, a block
1393                  * bitmap, and an inode table.
1394                  */
1395                 overhead += (sbi->s_groups_count *
1396                              (2 + sbi->s_itb_per_group));
1397                 sbi->s_overhead_last = overhead;
1398                 smp_wmb();
1399                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1400         }
1401 
1402         buf->f_type = EXT2_SUPER_MAGIC;
1403         buf->f_bsize = sb->s_blocksize;
1404         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1405         buf->f_bfree = ext2_count_free_blocks(sb);
1406         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1407         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1408         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1409                 buf->f_bavail = 0;
1410         buf->f_files = le32_to_cpu(es->s_inodes_count);
1411         buf->f_ffree = ext2_count_free_inodes(sb);
1412         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1413         buf->f_namelen = EXT2_NAME_LEN;
1414         fsid = le64_to_cpup((void *)es->s_uuid) ^
1415                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1416         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1417         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1418         spin_unlock(&sbi->s_lock);
1419         return 0;
1420 }
1421 
1422 static struct dentry *ext2_mount(struct file_system_type *fs_type,
1423         int flags, const char *dev_name, void *data)
1424 {
1425         return mount_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1426 }
1427 
1428 #ifdef CONFIG_QUOTA
1429 
1430 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1431  * acquiring the locks... As quota files are never truncated and quota code
1432  * itself serializes the operations (and no one else should touch the files)
1433  * we don't have to be afraid of races */
1434 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1435                                size_t len, loff_t off)
1436 {
1437         struct inode *inode = sb_dqopt(sb)->files[type];
1438         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1439         int err = 0;
1440         int offset = off & (sb->s_blocksize - 1);
1441         int tocopy;
1442         size_t toread;
1443         struct buffer_head tmp_bh;
1444         struct buffer_head *bh;
1445         loff_t i_size = i_size_read(inode);
1446 
1447         if (off > i_size)
1448                 return 0;
1449         if (off+len > i_size)
1450                 len = i_size-off;
1451         toread = len;
1452         while (toread > 0) {
1453                 tocopy = sb->s_blocksize - offset < toread ?
1454                                 sb->s_blocksize - offset : toread;
1455 
1456                 tmp_bh.b_state = 0;
1457                 tmp_bh.b_size = sb->s_blocksize;
1458                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1459                 if (err < 0)
1460                         return err;
1461                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1462                         memset(data, 0, tocopy);
1463                 else {
1464                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1465                         if (!bh)
1466                                 return -EIO;
1467                         memcpy(data, bh->b_data+offset, tocopy);
1468                         brelse(bh);
1469                 }
1470                 offset = 0;
1471                 toread -= tocopy;
1472                 data += tocopy;
1473                 blk++;
1474         }
1475         return len;
1476 }
1477 
1478 /* Write to quotafile */
1479 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1480                                 const char *data, size_t len, loff_t off)
1481 {
1482         struct inode *inode = sb_dqopt(sb)->files[type];
1483         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1484         int err = 0;
1485         int offset = off & (sb->s_blocksize - 1);
1486         int tocopy;
1487         size_t towrite = len;
1488         struct buffer_head tmp_bh;
1489         struct buffer_head *bh;
1490 
1491         while (towrite > 0) {
1492                 tocopy = sb->s_blocksize - offset < towrite ?
1493                                 sb->s_blocksize - offset : towrite;
1494 
1495                 tmp_bh.b_state = 0;
1496                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1497                 if (err < 0)
1498                         goto out;
1499                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1500                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1501                 else
1502                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1503                 if (unlikely(!bh)) {
1504                         err = -EIO;
1505                         goto out;
1506                 }
1507                 lock_buffer(bh);
1508                 memcpy(bh->b_data+offset, data, tocopy);
1509                 flush_dcache_page(bh->b_page);
1510                 set_buffer_uptodate(bh);
1511                 mark_buffer_dirty(bh);
1512                 unlock_buffer(bh);
1513                 brelse(bh);
1514                 offset = 0;
1515                 towrite -= tocopy;
1516                 data += tocopy;
1517                 blk++;
1518         }
1519 out:
1520         if (len == towrite)
1521                 return err;
1522         if (inode->i_size < off+len-towrite)
1523                 i_size_write(inode, off+len-towrite);
1524         inode->i_version++;
1525         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1526         mark_inode_dirty(inode);
1527         return len - towrite;
1528 }
1529 
1530 #endif
1531 
1532 static struct file_system_type ext2_fs_type = {
1533         .owner          = THIS_MODULE,
1534         .name           = "ext2",
1535         .mount          = ext2_mount,
1536         .kill_sb        = kill_block_super,
1537         .fs_flags       = FS_REQUIRES_DEV,
1538 };
1539 MODULE_ALIAS_FS("ext2");
1540 
1541 static int __init init_ext2_fs(void)
1542 {
1543         int err = init_ext2_xattr();
1544         if (err)
1545                 return err;
1546         err = init_inodecache();
1547         if (err)
1548                 goto out1;
1549         err = register_filesystem(&ext2_fs_type);
1550         if (err)
1551                 goto out;
1552         return 0;
1553 out:
1554         destroy_inodecache();
1555 out1:
1556         exit_ext2_xattr();
1557         return err;
1558 }
1559 
1560 static void __exit exit_ext2_fs(void)
1561 {
1562         unregister_filesystem(&ext2_fs_type);
1563         destroy_inodecache();
1564         exit_ext2_xattr();
1565 }
1566 
1567 MODULE_AUTHOR("Remy Card and others");
1568 MODULE_DESCRIPTION("Second Extended Filesystem");
1569 MODULE_LICENSE("GPL");
1570 module_init(init_ext2_fs)
1571 module_exit(exit_ext2_fs)
1572 

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