BKL: Explicitly add BKL around get_sb/fill_super
[linux-2.6.git] / fs / ext2 / super.c
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
46 void ext2_error (struct super_block * sb, const char * function,
47                  const char * fmt, ...)
48 {
49         va_list args;
50         struct ext2_sb_info *sbi = EXT2_SB(sb);
51         struct ext2_super_block *es = sbi->s_es;
52
53         if (!(sb->s_flags & MS_RDONLY)) {
54                 spin_lock(&sbi->s_lock);
55                 sbi->s_mount_state |= EXT2_ERROR_FS;
56                 es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
57                 spin_unlock(&sbi->s_lock);
58                 ext2_sync_super(sb, es, 1);
59         }
60
61         va_start(args, fmt);
62         printk(KERN_CRIT "EXT2-fs (%s): error: %s: ", sb->s_id, function);
63         vprintk(fmt, args);
64         printk("\n");
65         va_end(args);
66
67         if (test_opt(sb, ERRORS_PANIC))
68                 panic("EXT2-fs: panic from previous error\n");
69         if (test_opt(sb, ERRORS_RO)) {
70                 ext2_msg(sb, KERN_CRIT,
71                              "error: remounting filesystem read-only");
72                 sb->s_flags |= MS_RDONLY;
73         }
74 }
75
76 void ext2_msg(struct super_block *sb, const char *prefix,
77                 const char *fmt, ...)
78 {
79         va_list args;
80
81         va_start(args, fmt);
82         printk("%sEXT2-fs (%s): ", prefix, sb->s_id);
83         vprintk(fmt, args);
84         printk("\n");
85         va_end(args);
86 }
87
88 /*
89  * This must be called with sbi->s_lock held.
90  */
91 void ext2_update_dynamic_rev(struct super_block *sb)
92 {
93         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
94
95         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
96                 return;
97
98         ext2_msg(sb, KERN_WARNING,
99                      "warning: updating to rev %d because of "
100                      "new feature flag, running e2fsck is recommended",
101                      EXT2_DYNAMIC_REV);
102
103         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
104         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
105         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
106         /* leave es->s_feature_*compat flags alone */
107         /* es->s_uuid will be set by e2fsck if empty */
108
109         /*
110          * The rest of the superblock fields should be zero, and if not it
111          * means they are likely already in use, so leave them alone.  We
112          * can leave it up to e2fsck to clean up any inconsistencies there.
113          */
114 }
115
116 static void ext2_put_super (struct super_block * sb)
117 {
118         int db_count;
119         int i;
120         struct ext2_sb_info *sbi = EXT2_SB(sb);
121
122         dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
123
124         if (sb->s_dirt)
125                 ext2_write_super(sb);
126
127         ext2_xattr_put_super(sb);
128         if (!(sb->s_flags & MS_RDONLY)) {
129                 struct ext2_super_block *es = sbi->s_es;
130
131                 spin_lock(&sbi->s_lock);
132                 es->s_state = cpu_to_le16(sbi->s_mount_state);
133                 spin_unlock(&sbi->s_lock);
134                 ext2_sync_super(sb, es, 1);
135         }
136         db_count = sbi->s_gdb_count;
137         for (i = 0; i < db_count; i++)
138                 if (sbi->s_group_desc[i])
139                         brelse (sbi->s_group_desc[i]);
140         kfree(sbi->s_group_desc);
141         kfree(sbi->s_debts);
142         percpu_counter_destroy(&sbi->s_freeblocks_counter);
143         percpu_counter_destroy(&sbi->s_freeinodes_counter);
144         percpu_counter_destroy(&sbi->s_dirs_counter);
145         brelse (sbi->s_sbh);
146         sb->s_fs_info = NULL;
147         kfree(sbi->s_blockgroup_lock);
148         kfree(sbi);
149 }
150
151 static struct kmem_cache * ext2_inode_cachep;
152
153 static struct inode *ext2_alloc_inode(struct super_block *sb)
154 {
155         struct ext2_inode_info *ei;
156         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
157         if (!ei)
158                 return NULL;
159         ei->i_block_alloc_info = NULL;
160         ei->vfs_inode.i_version = 1;
161         return &ei->vfs_inode;
162 }
163
164 static void ext2_destroy_inode(struct inode *inode)
165 {
166         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
167 }
168
169 static void init_once(void *foo)
170 {
171         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
172
173         rwlock_init(&ei->i_meta_lock);
174 #ifdef CONFIG_EXT2_FS_XATTR
175         init_rwsem(&ei->xattr_sem);
176 #endif
177         mutex_init(&ei->truncate_mutex);
178         inode_init_once(&ei->vfs_inode);
179 }
180
181 static int init_inodecache(void)
182 {
183         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
184                                              sizeof(struct ext2_inode_info),
185                                              0, (SLAB_RECLAIM_ACCOUNT|
186                                                 SLAB_MEM_SPREAD),
187                                              init_once);
188         if (ext2_inode_cachep == NULL)
189                 return -ENOMEM;
190         return 0;
191 }
192
193 static void destroy_inodecache(void)
194 {
195         kmem_cache_destroy(ext2_inode_cachep);
196 }
197
198 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
199 {
200         struct super_block *sb = vfs->mnt_sb;
201         struct ext2_sb_info *sbi = EXT2_SB(sb);
202         struct ext2_super_block *es = sbi->s_es;
203         unsigned long def_mount_opts;
204
205         spin_lock(&sbi->s_lock);
206         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
207
208         if (sbi->s_sb_block != 1)
209                 seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
210         if (test_opt(sb, MINIX_DF))
211                 seq_puts(seq, ",minixdf");
212         if (test_opt(sb, GRPID))
213                 seq_puts(seq, ",grpid");
214         if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
215                 seq_puts(seq, ",nogrpid");
216         if (sbi->s_resuid != EXT2_DEF_RESUID ||
217             le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
218                 seq_printf(seq, ",resuid=%u", sbi->s_resuid);
219         }
220         if (sbi->s_resgid != EXT2_DEF_RESGID ||
221             le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
222                 seq_printf(seq, ",resgid=%u", sbi->s_resgid);
223         }
224         if (test_opt(sb, ERRORS_RO)) {
225                 int def_errors = le16_to_cpu(es->s_errors);
226
227                 if (def_errors == EXT2_ERRORS_PANIC ||
228                     def_errors == EXT2_ERRORS_CONTINUE) {
229                         seq_puts(seq, ",errors=remount-ro");
230                 }
231         }
232         if (test_opt(sb, ERRORS_CONT))
233                 seq_puts(seq, ",errors=continue");
234         if (test_opt(sb, ERRORS_PANIC))
235                 seq_puts(seq, ",errors=panic");
236         if (test_opt(sb, NO_UID32))
237                 seq_puts(seq, ",nouid32");
238         if (test_opt(sb, DEBUG))
239                 seq_puts(seq, ",debug");
240         if (test_opt(sb, OLDALLOC))
241                 seq_puts(seq, ",oldalloc");
242
243 #ifdef CONFIG_EXT2_FS_XATTR
244         if (test_opt(sb, XATTR_USER))
245                 seq_puts(seq, ",user_xattr");
246         if (!test_opt(sb, XATTR_USER) &&
247             (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
248                 seq_puts(seq, ",nouser_xattr");
249         }
250 #endif
251
252 #ifdef CONFIG_EXT2_FS_POSIX_ACL
253         if (test_opt(sb, POSIX_ACL))
254                 seq_puts(seq, ",acl");
255         if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
256                 seq_puts(seq, ",noacl");
257 #endif
258
259         if (test_opt(sb, NOBH))
260                 seq_puts(seq, ",nobh");
261
262 #if defined(CONFIG_QUOTA)
263         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
264                 seq_puts(seq, ",usrquota");
265
266         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
267                 seq_puts(seq, ",grpquota");
268 #endif
269
270 #if defined(CONFIG_EXT2_FS_XIP)
271         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
272                 seq_puts(seq, ",xip");
273 #endif
274
275         if (!test_opt(sb, RESERVATION))
276                 seq_puts(seq, ",noreservation");
277
278         spin_unlock(&sbi->s_lock);
279         return 0;
280 }
281
282 #ifdef CONFIG_QUOTA
283 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
284 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
285 #endif
286
287 static const struct super_operations ext2_sops = {
288         .alloc_inode    = ext2_alloc_inode,
289         .destroy_inode  = ext2_destroy_inode,
290         .write_inode    = ext2_write_inode,
291         .evict_inode    = ext2_evict_inode,
292         .put_super      = ext2_put_super,
293         .write_super    = ext2_write_super,
294         .sync_fs        = ext2_sync_fs,
295         .statfs         = ext2_statfs,
296         .remount_fs     = ext2_remount,
297         .show_options   = ext2_show_options,
298 #ifdef CONFIG_QUOTA
299         .quota_read     = ext2_quota_read,
300         .quota_write    = ext2_quota_write,
301 #endif
302 };
303
304 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
305                 u64 ino, u32 generation)
306 {
307         struct inode *inode;
308
309         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
310                 return ERR_PTR(-ESTALE);
311         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
312                 return ERR_PTR(-ESTALE);
313
314         /* iget isn't really right if the inode is currently unallocated!!
315          * ext2_read_inode currently does appropriate checks, but
316          * it might be "neater" to call ext2_get_inode first and check
317          * if the inode is valid.....
318          */
319         inode = ext2_iget(sb, ino);
320         if (IS_ERR(inode))
321                 return ERR_CAST(inode);
322         if (generation && inode->i_generation != generation) {
323                 /* we didn't find the right inode.. */
324                 iput(inode);
325                 return ERR_PTR(-ESTALE);
326         }
327         return inode;
328 }
329
330 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
331                 int fh_len, int fh_type)
332 {
333         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
334                                     ext2_nfs_get_inode);
335 }
336
337 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
338                 int fh_len, int fh_type)
339 {
340         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
341                                     ext2_nfs_get_inode);
342 }
343
344 /* Yes, most of these are left as NULL!!
345  * A NULL value implies the default, which works with ext2-like file
346  * systems, but can be improved upon.
347  * Currently only get_parent is required.
348  */
349 static const struct export_operations ext2_export_ops = {
350         .fh_to_dentry = ext2_fh_to_dentry,
351         .fh_to_parent = ext2_fh_to_parent,
352         .get_parent = ext2_get_parent,
353 };
354
355 static unsigned long get_sb_block(void **data)
356 {
357         unsigned long   sb_block;
358         char            *options = (char *) *data;
359
360         if (!options || strncmp(options, "sb=", 3) != 0)
361                 return 1;       /* Default location */
362         options += 3;
363         sb_block = simple_strtoul(options, &options, 0);
364         if (*options && *options != ',') {
365                 printk("EXT2-fs: Invalid sb specification: %s\n",
366                        (char *) *data);
367                 return 1;
368         }
369         if (*options == ',')
370                 options++;
371         *data = (void *) options;
372         return sb_block;
373 }
374
375 enum {
376         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
377         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
378         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
379         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
380         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
381         Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
382 };
383
384 static const match_table_t tokens = {
385         {Opt_bsd_df, "bsddf"},
386         {Opt_minix_df, "minixdf"},
387         {Opt_grpid, "grpid"},
388         {Opt_grpid, "bsdgroups"},
389         {Opt_nogrpid, "nogrpid"},
390         {Opt_nogrpid, "sysvgroups"},
391         {Opt_resgid, "resgid=%u"},
392         {Opt_resuid, "resuid=%u"},
393         {Opt_sb, "sb=%u"},
394         {Opt_err_cont, "errors=continue"},
395         {Opt_err_panic, "errors=panic"},
396         {Opt_err_ro, "errors=remount-ro"},
397         {Opt_nouid32, "nouid32"},
398         {Opt_nocheck, "check=none"},
399         {Opt_nocheck, "nocheck"},
400         {Opt_debug, "debug"},
401         {Opt_oldalloc, "oldalloc"},
402         {Opt_orlov, "orlov"},
403         {Opt_nobh, "nobh"},
404         {Opt_user_xattr, "user_xattr"},
405         {Opt_nouser_xattr, "nouser_xattr"},
406         {Opt_acl, "acl"},
407         {Opt_noacl, "noacl"},
408         {Opt_xip, "xip"},
409         {Opt_grpquota, "grpquota"},
410         {Opt_ignore, "noquota"},
411         {Opt_quota, "quota"},
412         {Opt_usrquota, "usrquota"},
413         {Opt_reservation, "reservation"},
414         {Opt_noreservation, "noreservation"},
415         {Opt_err, NULL}
416 };
417
418 static int parse_options(char *options, struct super_block *sb)
419 {
420         char *p;
421         struct ext2_sb_info *sbi = EXT2_SB(sb);
422         substring_t args[MAX_OPT_ARGS];
423         int option;
424
425         if (!options)
426                 return 1;
427
428         while ((p = strsep (&options, ",")) != NULL) {
429                 int token;
430                 if (!*p)
431                         continue;
432
433                 token = match_token(p, tokens, args);
434                 switch (token) {
435                 case Opt_bsd_df:
436                         clear_opt (sbi->s_mount_opt, MINIX_DF);
437                         break;
438                 case Opt_minix_df:
439                         set_opt (sbi->s_mount_opt, MINIX_DF);
440                         break;
441                 case Opt_grpid:
442                         set_opt (sbi->s_mount_opt, GRPID);
443                         break;
444                 case Opt_nogrpid:
445                         clear_opt (sbi->s_mount_opt, GRPID);
446                         break;
447                 case Opt_resuid:
448                         if (match_int(&args[0], &option))
449                                 return 0;
450                         sbi->s_resuid = option;
451                         break;
452                 case Opt_resgid:
453                         if (match_int(&args[0], &option))
454                                 return 0;
455                         sbi->s_resgid = option;
456                         break;
457                 case Opt_sb:
458                         /* handled by get_sb_block() instead of here */
459                         /* *sb_block = match_int(&args[0]); */
460                         break;
461                 case Opt_err_panic:
462                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
463                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
464                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
465                         break;
466                 case Opt_err_ro:
467                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
468                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
469                         set_opt (sbi->s_mount_opt, ERRORS_RO);
470                         break;
471                 case Opt_err_cont:
472                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
473                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
474                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
475                         break;
476                 case Opt_nouid32:
477                         set_opt (sbi->s_mount_opt, NO_UID32);
478                         break;
479                 case Opt_nocheck:
480                         clear_opt (sbi->s_mount_opt, CHECK);
481                         break;
482                 case Opt_debug:
483                         set_opt (sbi->s_mount_opt, DEBUG);
484                         break;
485                 case Opt_oldalloc:
486                         set_opt (sbi->s_mount_opt, OLDALLOC);
487                         break;
488                 case Opt_orlov:
489                         clear_opt (sbi->s_mount_opt, OLDALLOC);
490                         break;
491                 case Opt_nobh:
492                         set_opt (sbi->s_mount_opt, NOBH);
493                         break;
494 #ifdef CONFIG_EXT2_FS_XATTR
495                 case Opt_user_xattr:
496                         set_opt (sbi->s_mount_opt, XATTR_USER);
497                         break;
498                 case Opt_nouser_xattr:
499                         clear_opt (sbi->s_mount_opt, XATTR_USER);
500                         break;
501 #else
502                 case Opt_user_xattr:
503                 case Opt_nouser_xattr:
504                         ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
505                                 "not supported");
506                         break;
507 #endif
508 #ifdef CONFIG_EXT2_FS_POSIX_ACL
509                 case Opt_acl:
510                         set_opt(sbi->s_mount_opt, POSIX_ACL);
511                         break;
512                 case Opt_noacl:
513                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
514                         break;
515 #else
516                 case Opt_acl:
517                 case Opt_noacl:
518                         ext2_msg(sb, KERN_INFO,
519                                 "(no)acl options not supported");
520                         break;
521 #endif
522                 case Opt_xip:
523 #ifdef CONFIG_EXT2_FS_XIP
524                         set_opt (sbi->s_mount_opt, XIP);
525 #else
526                         ext2_msg(sb, KERN_INFO, "xip option not supported");
527 #endif
528                         break;
529
530 #if defined(CONFIG_QUOTA)
531                 case Opt_quota:
532                 case Opt_usrquota:
533                         set_opt(sbi->s_mount_opt, USRQUOTA);
534                         break;
535
536                 case Opt_grpquota:
537                         set_opt(sbi->s_mount_opt, GRPQUOTA);
538                         break;
539 #else
540                 case Opt_quota:
541                 case Opt_usrquota:
542                 case Opt_grpquota:
543                         ext2_msg(sb, KERN_INFO,
544                                 "quota operations not supported");
545                         break;
546 #endif
547
548                 case Opt_reservation:
549                         set_opt(sbi->s_mount_opt, RESERVATION);
550                         ext2_msg(sb, KERN_INFO, "reservations ON");
551                         break;
552                 case Opt_noreservation:
553                         clear_opt(sbi->s_mount_opt, RESERVATION);
554                         ext2_msg(sb, KERN_INFO, "reservations OFF");
555                         break;
556                 case Opt_ignore:
557                         break;
558                 default:
559                         return 0;
560                 }
561         }
562         return 1;
563 }
564
565 static int ext2_setup_super (struct super_block * sb,
566                               struct ext2_super_block * es,
567                               int read_only)
568 {
569         int res = 0;
570         struct ext2_sb_info *sbi = EXT2_SB(sb);
571
572         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
573                 ext2_msg(sb, KERN_ERR,
574                         "error: revision level too high, "
575                         "forcing read-only mode");
576                 res = MS_RDONLY;
577         }
578         if (read_only)
579                 return res;
580         if (!(sbi->s_mount_state & EXT2_VALID_FS))
581                 ext2_msg(sb, KERN_WARNING,
582                         "warning: mounting unchecked fs, "
583                         "running e2fsck is recommended");
584         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
585                 ext2_msg(sb, KERN_WARNING,
586                         "warning: mounting fs with errors, "
587                         "running e2fsck is recommended");
588         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
589                  le16_to_cpu(es->s_mnt_count) >=
590                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
591                 ext2_msg(sb, KERN_WARNING,
592                         "warning: maximal mount count reached, "
593                         "running e2fsck is recommended");
594         else if (le32_to_cpu(es->s_checkinterval) &&
595                 (le32_to_cpu(es->s_lastcheck) +
596                         le32_to_cpu(es->s_checkinterval) <= get_seconds()))
597                 ext2_msg(sb, KERN_WARNING,
598                         "warning: checktime reached, "
599                         "running e2fsck is recommended");
600         if (!le16_to_cpu(es->s_max_mnt_count))
601                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
602         le16_add_cpu(&es->s_mnt_count, 1);
603         if (test_opt (sb, DEBUG))
604                 ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
605                         "bpg=%lu, ipg=%lu, mo=%04lx]",
606                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
607                         sbi->s_frag_size,
608                         sbi->s_groups_count,
609                         EXT2_BLOCKS_PER_GROUP(sb),
610                         EXT2_INODES_PER_GROUP(sb),
611                         sbi->s_mount_opt);
612         return res;
613 }
614
615 static int ext2_check_descriptors(struct super_block *sb)
616 {
617         int i;
618         struct ext2_sb_info *sbi = EXT2_SB(sb);
619
620         ext2_debug ("Checking group descriptors");
621
622         for (i = 0; i < sbi->s_groups_count; i++) {
623                 struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
624                 ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
625                 ext2_fsblk_t last_block;
626
627                 if (i == sbi->s_groups_count - 1)
628                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
629                 else
630                         last_block = first_block +
631                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
632
633                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
634                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
635                 {
636                         ext2_error (sb, "ext2_check_descriptors",
637                                     "Block bitmap for group %d"
638                                     " not in group (block %lu)!",
639                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
640                         return 0;
641                 }
642                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
643                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
644                 {
645                         ext2_error (sb, "ext2_check_descriptors",
646                                     "Inode bitmap for group %d"
647                                     " not in group (block %lu)!",
648                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
649                         return 0;
650                 }
651                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
652                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
653                     last_block)
654                 {
655                         ext2_error (sb, "ext2_check_descriptors",
656                                     "Inode table for group %d"
657                                     " not in group (block %lu)!",
658                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
659                         return 0;
660                 }
661         }
662         return 1;
663 }
664
665 /*
666  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
667  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
668  * We need to be 1 filesystem block less than the 2^32 sector limit.
669  */
670 static loff_t ext2_max_size(int bits)
671 {
672         loff_t res = EXT2_NDIR_BLOCKS;
673         int meta_blocks;
674         loff_t upper_limit;
675
676         /* This is calculated to be the largest file size for a
677          * dense, file such that the total number of
678          * sectors in the file, including data and all indirect blocks,
679          * does not exceed 2^32 -1
680          * __u32 i_blocks representing the total number of
681          * 512 bytes blocks of the file
682          */
683         upper_limit = (1LL << 32) - 1;
684
685         /* total blocks in file system block size */
686         upper_limit >>= (bits - 9);
687
688
689         /* indirect blocks */
690         meta_blocks = 1;
691         /* double indirect blocks */
692         meta_blocks += 1 + (1LL << (bits-2));
693         /* tripple indirect blocks */
694         meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
695
696         upper_limit -= meta_blocks;
697         upper_limit <<= bits;
698
699         res += 1LL << (bits-2);
700         res += 1LL << (2*(bits-2));
701         res += 1LL << (3*(bits-2));
702         res <<= bits;
703         if (res > upper_limit)
704                 res = upper_limit;
705
706         if (res > MAX_LFS_FILESIZE)
707                 res = MAX_LFS_FILESIZE;
708
709         return res;
710 }
711
712 static unsigned long descriptor_loc(struct super_block *sb,
713                                     unsigned long logic_sb_block,
714                                     int nr)
715 {
716         struct ext2_sb_info *sbi = EXT2_SB(sb);
717         unsigned long bg, first_meta_bg;
718         int has_super = 0;
719         
720         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
721
722         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
723             nr < first_meta_bg)
724                 return (logic_sb_block + nr + 1);
725         bg = sbi->s_desc_per_block * nr;
726         if (ext2_bg_has_super(sb, bg))
727                 has_super = 1;
728
729         return ext2_group_first_block_no(sb, bg) + has_super;
730 }
731
732 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
733 {
734         struct buffer_head * bh;
735         struct ext2_sb_info * sbi;
736         struct ext2_super_block * es;
737         struct inode *root;
738         unsigned long block;
739         unsigned long sb_block = get_sb_block(&data);
740         unsigned long logic_sb_block;
741         unsigned long offset = 0;
742         unsigned long def_mount_opts;
743         long ret = -EINVAL;
744         int blocksize = BLOCK_SIZE;
745         int db_count;
746         int i, j;
747         __le32 features;
748         int err;
749
750         lock_kernel();
751
752         err = -ENOMEM;
753         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
754         if (!sbi)
755                 goto failed_unlock;
756
757         sbi->s_blockgroup_lock =
758                 kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
759         if (!sbi->s_blockgroup_lock) {
760                 kfree(sbi);
761                 goto failed_unlock;
762         }
763         sb->s_fs_info = sbi;
764         sbi->s_sb_block = sb_block;
765
766         spin_lock_init(&sbi->s_lock);
767
768         /*
769          * See what the current blocksize for the device is, and
770          * use that as the blocksize.  Otherwise (or if the blocksize
771          * is smaller than the default) use the default.
772          * This is important for devices that have a hardware
773          * sectorsize that is larger than the default.
774          */
775         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
776         if (!blocksize) {
777                 ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
778                 goto failed_sbi;
779         }
780
781         /*
782          * If the superblock doesn't start on a hardware sector boundary,
783          * calculate the offset.  
784          */
785         if (blocksize != BLOCK_SIZE) {
786                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
787                 offset = (sb_block*BLOCK_SIZE) % blocksize;
788         } else {
789                 logic_sb_block = sb_block;
790         }
791
792         if (!(bh = sb_bread(sb, logic_sb_block))) {
793                 ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
794                 goto failed_sbi;
795         }
796         /*
797          * Note: s_es must be initialized as soon as possible because
798          *       some ext2 macro-instructions depend on its value
799          */
800         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
801         sbi->s_es = es;
802         sb->s_magic = le16_to_cpu(es->s_magic);
803
804         if (sb->s_magic != EXT2_SUPER_MAGIC)
805                 goto cantfind_ext2;
806
807         /* Set defaults before we parse the mount options */
808         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
809         if (def_mount_opts & EXT2_DEFM_DEBUG)
810                 set_opt(sbi->s_mount_opt, DEBUG);
811         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
812                 set_opt(sbi->s_mount_opt, GRPID);
813         if (def_mount_opts & EXT2_DEFM_UID16)
814                 set_opt(sbi->s_mount_opt, NO_UID32);
815 #ifdef CONFIG_EXT2_FS_XATTR
816         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
817                 set_opt(sbi->s_mount_opt, XATTR_USER);
818 #endif
819 #ifdef CONFIG_EXT2_FS_POSIX_ACL
820         if (def_mount_opts & EXT2_DEFM_ACL)
821                 set_opt(sbi->s_mount_opt, POSIX_ACL);
822 #endif
823         
824         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
825                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
826         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
827                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
828         else
829                 set_opt(sbi->s_mount_opt, ERRORS_RO);
830
831         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
832         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
833         
834         set_opt(sbi->s_mount_opt, RESERVATION);
835
836         if (!parse_options((char *) data, sb))
837                 goto failed_mount;
838
839         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
840                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
841                  MS_POSIXACL : 0);
842
843         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
844                                     EXT2_MOUNT_XIP if not */
845
846         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
847             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
848              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
849              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
850                 ext2_msg(sb, KERN_WARNING,
851                         "warning: feature flags set on rev 0 fs, "
852                         "running e2fsck is recommended");
853         /*
854          * Check feature flags regardless of the revision level, since we
855          * previously didn't change the revision level when setting the flags,
856          * so there is a chance incompat flags are set on a rev 0 filesystem.
857          */
858         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
859         if (features) {
860                 ext2_msg(sb, KERN_ERR,  "error: couldn't mount because of "
861                        "unsupported optional features (%x)",
862                         le32_to_cpu(features));
863                 goto failed_mount;
864         }
865         if (!(sb->s_flags & MS_RDONLY) &&
866             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
867                 ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
868                        "unsupported optional features (%x)",
869                        le32_to_cpu(features));
870                 goto failed_mount;
871         }
872
873         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
874
875         if (ext2_use_xip(sb) && blocksize != PAGE_SIZE) {
876                 if (!silent)
877                         ext2_msg(sb, KERN_ERR,
878                                 "error: unsupported blocksize for xip");
879                 goto failed_mount;
880         }
881
882         /* If the blocksize doesn't match, re-read the thing.. */
883         if (sb->s_blocksize != blocksize) {
884                 brelse(bh);
885
886                 if (!sb_set_blocksize(sb, blocksize)) {
887                         ext2_msg(sb, KERN_ERR, "error: blocksize is too small");
888                         goto failed_sbi;
889                 }
890
891                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
892                 offset = (sb_block*BLOCK_SIZE) % blocksize;
893                 bh = sb_bread(sb, logic_sb_block);
894                 if(!bh) {
895                         ext2_msg(sb, KERN_ERR, "error: couldn't read"
896                                 "superblock on 2nd try");
897                         goto failed_sbi;
898                 }
899                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
900                 sbi->s_es = es;
901                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
902                         ext2_msg(sb, KERN_ERR, "error: magic mismatch");
903                         goto failed_mount;
904                 }
905         }
906
907         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
908
909         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
910                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
911                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
912         } else {
913                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
914                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
915                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
916                     !is_power_of_2(sbi->s_inode_size) ||
917                     (sbi->s_inode_size > blocksize)) {
918                         ext2_msg(sb, KERN_ERR,
919                                 "error: unsupported inode size: %d",
920                                 sbi->s_inode_size);
921                         goto failed_mount;
922                 }
923         }
924
925         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
926                                    le32_to_cpu(es->s_log_frag_size);
927         if (sbi->s_frag_size == 0)
928                 goto cantfind_ext2;
929         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
930
931         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
932         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
933         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
934
935         if (EXT2_INODE_SIZE(sb) == 0)
936                 goto cantfind_ext2;
937         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
938         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
939                 goto cantfind_ext2;
940         sbi->s_itb_per_group = sbi->s_inodes_per_group /
941                                         sbi->s_inodes_per_block;
942         sbi->s_desc_per_block = sb->s_blocksize /
943                                         sizeof (struct ext2_group_desc);
944         sbi->s_sbh = bh;
945         sbi->s_mount_state = le16_to_cpu(es->s_state);
946         sbi->s_addr_per_block_bits =
947                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
948         sbi->s_desc_per_block_bits =
949                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
950
951         if (sb->s_magic != EXT2_SUPER_MAGIC)
952                 goto cantfind_ext2;
953
954         if (sb->s_blocksize != bh->b_size) {
955                 if (!silent)
956                         ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
957                 goto failed_mount;
958         }
959
960         if (sb->s_blocksize != sbi->s_frag_size) {
961                 ext2_msg(sb, KERN_ERR,
962                         "error: fragsize %lu != blocksize %lu"
963                         "(not supported yet)",
964                         sbi->s_frag_size, sb->s_blocksize);
965                 goto failed_mount;
966         }
967
968         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
969                 ext2_msg(sb, KERN_ERR,
970                         "error: #blocks per group too big: %lu",
971                         sbi->s_blocks_per_group);
972                 goto failed_mount;
973         }
974         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
975                 ext2_msg(sb, KERN_ERR,
976                         "error: #fragments per group too big: %lu",
977                         sbi->s_frags_per_group);
978                 goto failed_mount;
979         }
980         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
981                 ext2_msg(sb, KERN_ERR,
982                         "error: #inodes per group too big: %lu",
983                         sbi->s_inodes_per_group);
984                 goto failed_mount;
985         }
986
987         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
988                 goto cantfind_ext2;
989         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
990                                 le32_to_cpu(es->s_first_data_block) - 1)
991                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
992         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
993                    EXT2_DESC_PER_BLOCK(sb);
994         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
995         if (sbi->s_group_desc == NULL) {
996                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
997                 goto failed_mount;
998         }
999         bgl_lock_init(sbi->s_blockgroup_lock);
1000         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1001         if (!sbi->s_debts) {
1002                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
1003                 goto failed_mount_group_desc;
1004         }
1005         for (i = 0; i < db_count; i++) {
1006                 block = descriptor_loc(sb, logic_sb_block, i);
1007                 sbi->s_group_desc[i] = sb_bread(sb, block);
1008                 if (!sbi->s_group_desc[i]) {
1009                         for (j = 0; j < i; j++)
1010                                 brelse (sbi->s_group_desc[j]);
1011                         ext2_msg(sb, KERN_ERR,
1012                                 "error: unable to read group descriptors");
1013                         goto failed_mount_group_desc;
1014                 }
1015         }
1016         if (!ext2_check_descriptors (sb)) {
1017                 ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1018                 goto failed_mount2;
1019         }
1020         sbi->s_gdb_count = db_count;
1021         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1022         spin_lock_init(&sbi->s_next_gen_lock);
1023
1024         /* per fileystem reservation list head & lock */
1025         spin_lock_init(&sbi->s_rsv_window_lock);
1026         sbi->s_rsv_window_root = RB_ROOT;
1027         /*
1028          * Add a single, static dummy reservation to the start of the
1029          * reservation window list --- it gives us a placeholder for
1030          * append-at-start-of-list which makes the allocation logic
1031          * _much_ simpler.
1032          */
1033         sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1034         sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1035         sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1036         sbi->s_rsv_window_head.rsv_goal_size = 0;
1037         ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1038
1039         err = percpu_counter_init(&sbi->s_freeblocks_counter,
1040                                 ext2_count_free_blocks(sb));
1041         if (!err) {
1042                 err = percpu_counter_init(&sbi->s_freeinodes_counter,
1043                                 ext2_count_free_inodes(sb));
1044         }
1045         if (!err) {
1046                 err = percpu_counter_init(&sbi->s_dirs_counter,
1047                                 ext2_count_dirs(sb));
1048         }
1049         if (err) {
1050                 ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1051                 goto failed_mount3;
1052         }
1053         /*
1054          * set up enough so that it can read an inode
1055          */
1056         sb->s_op = &ext2_sops;
1057         sb->s_export_op = &ext2_export_ops;
1058         sb->s_xattr = ext2_xattr_handlers;
1059
1060 #ifdef CONFIG_QUOTA
1061         sb->dq_op = &dquot_operations;
1062         sb->s_qcop = &dquot_quotactl_ops;
1063 #endif
1064
1065         root = ext2_iget(sb, EXT2_ROOT_INO);
1066         if (IS_ERR(root)) {
1067                 ret = PTR_ERR(root);
1068                 goto failed_mount3;
1069         }
1070         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1071                 iput(root);
1072                 ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1073                 goto failed_mount3;
1074         }
1075
1076         sb->s_root = d_alloc_root(root);
1077         if (!sb->s_root) {
1078                 iput(root);
1079                 ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1080                 ret = -ENOMEM;
1081                 goto failed_mount3;
1082         }
1083         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1084                 ext2_msg(sb, KERN_WARNING,
1085                         "warning: mounting ext3 filesystem as ext2");
1086         if (ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY))
1087                 sb->s_flags |= MS_RDONLY;
1088         ext2_write_super(sb);
1089         unlock_kernel();
1090         return 0;
1091
1092 cantfind_ext2:
1093         if (!silent)
1094                 ext2_msg(sb, KERN_ERR,
1095                         "error: can't find an ext2 filesystem on dev %s.",
1096                         sb->s_id);
1097         goto failed_mount;
1098 failed_mount3:
1099         percpu_counter_destroy(&sbi->s_freeblocks_counter);
1100         percpu_counter_destroy(&sbi->s_freeinodes_counter);
1101         percpu_counter_destroy(&sbi->s_dirs_counter);
1102 failed_mount2:
1103         for (i = 0; i < db_count; i++)
1104                 brelse(sbi->s_group_desc[i]);
1105 failed_mount_group_desc:
1106         kfree(sbi->s_group_desc);
1107         kfree(sbi->s_debts);
1108 failed_mount:
1109         brelse(bh);
1110 failed_sbi:
1111         sb->s_fs_info = NULL;
1112         kfree(sbi->s_blockgroup_lock);
1113         kfree(sbi);
1114 failed_unlock:
1115         unlock_kernel();
1116         return ret;
1117 }
1118
1119 static void ext2_clear_super_error(struct super_block *sb)
1120 {
1121         struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1122
1123         if (buffer_write_io_error(sbh)) {
1124                 /*
1125                  * Oh, dear.  A previous attempt to write the
1126                  * superblock failed.  This could happen because the
1127                  * USB device was yanked out.  Or it could happen to
1128                  * be a transient write error and maybe the block will
1129                  * be remapped.  Nothing we can do but to retry the
1130                  * write and hope for the best.
1131                  */
1132                 ext2_msg(sb, KERN_ERR,
1133                        "previous I/O error to superblock detected\n");
1134                 clear_buffer_write_io_error(sbh);
1135                 set_buffer_uptodate(sbh);
1136         }
1137 }
1138
1139 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
1140                             int wait)
1141 {
1142         ext2_clear_super_error(sb);
1143         spin_lock(&EXT2_SB(sb)->s_lock);
1144         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1145         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1146         es->s_wtime = cpu_to_le32(get_seconds());
1147         /* unlock before we do IO */
1148         spin_unlock(&EXT2_SB(sb)->s_lock);
1149         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1150         if (wait)
1151                 sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1152         sb->s_dirt = 0;
1153 }
1154
1155 /*
1156  * In the second extended file system, it is not necessary to
1157  * write the super block since we use a mapping of the
1158  * disk super block in a buffer.
1159  *
1160  * However, this function is still used to set the fs valid
1161  * flags to 0.  We need to set this flag to 0 since the fs
1162  * may have been checked while mounted and e2fsck may have
1163  * set s_state to EXT2_VALID_FS after some corrections.
1164  */
1165 static int ext2_sync_fs(struct super_block *sb, int wait)
1166 {
1167         struct ext2_sb_info *sbi = EXT2_SB(sb);
1168         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1169
1170         spin_lock(&sbi->s_lock);
1171         if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1172                 ext2_debug("setting valid to 0\n");
1173                 es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1174         }
1175         spin_unlock(&sbi->s_lock);
1176         ext2_sync_super(sb, es, wait);
1177         return 0;
1178 }
1179
1180
1181 void ext2_write_super(struct super_block *sb)
1182 {
1183         if (!(sb->s_flags & MS_RDONLY))
1184                 ext2_sync_fs(sb, 1);
1185         else
1186                 sb->s_dirt = 0;
1187 }
1188
1189 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1190 {
1191         struct ext2_sb_info * sbi = EXT2_SB(sb);
1192         struct ext2_super_block * es;
1193         unsigned long old_mount_opt = sbi->s_mount_opt;
1194         struct ext2_mount_options old_opts;
1195         unsigned long old_sb_flags;
1196         int err;
1197
1198         spin_lock(&sbi->s_lock);
1199
1200         /* Store the old options */
1201         old_sb_flags = sb->s_flags;
1202         old_opts.s_mount_opt = sbi->s_mount_opt;
1203         old_opts.s_resuid = sbi->s_resuid;
1204         old_opts.s_resgid = sbi->s_resgid;
1205
1206         /*
1207          * Allow the "check" option to be passed as a remount option.
1208          */
1209         if (!parse_options(data, sb)) {
1210                 err = -EINVAL;
1211                 goto restore_opts;
1212         }
1213
1214         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1215                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1216
1217         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1218                                     EXT2_MOUNT_XIP if not */
1219
1220         if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1221                 ext2_msg(sb, KERN_WARNING,
1222                         "warning: unsupported blocksize for xip");
1223                 err = -EINVAL;
1224                 goto restore_opts;
1225         }
1226
1227         es = sbi->s_es;
1228         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1229             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1230             invalidate_inodes(sb)) {
1231                 ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1232                          "xip flag with busy inodes while remounting");
1233                 sbi->s_mount_opt &= ~EXT2_MOUNT_XIP;
1234                 sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;
1235         }
1236         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
1237                 spin_unlock(&sbi->s_lock);
1238                 return 0;
1239         }
1240         if (*flags & MS_RDONLY) {
1241                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1242                     !(sbi->s_mount_state & EXT2_VALID_FS)) {
1243                         spin_unlock(&sbi->s_lock);
1244                         return 0;
1245                 }
1246
1247                 /*
1248                  * OK, we are remounting a valid rw partition rdonly, so set
1249                  * the rdonly flag and then mark the partition as valid again.
1250                  */
1251                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1252                 es->s_mtime = cpu_to_le32(get_seconds());
1253                 spin_unlock(&sbi->s_lock);
1254
1255                 err = dquot_suspend(sb, -1);
1256                 if (err < 0) {
1257                         spin_lock(&sbi->s_lock);
1258                         goto restore_opts;
1259                 }
1260
1261                 ext2_sync_super(sb, es, 1);
1262         } else {
1263                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1264                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1265                 if (ret) {
1266                         ext2_msg(sb, KERN_WARNING,
1267                                 "warning: couldn't remount RDWR because of "
1268                                 "unsupported optional features (%x).",
1269                                 le32_to_cpu(ret));
1270                         err = -EROFS;
1271                         goto restore_opts;
1272                 }
1273                 /*
1274                  * Mounting a RDONLY partition read-write, so reread and
1275                  * store the current valid flag.  (It may have been changed
1276                  * by e2fsck since we originally mounted the partition.)
1277                  */
1278                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1279                 if (!ext2_setup_super (sb, es, 0))
1280                         sb->s_flags &= ~MS_RDONLY;
1281                 spin_unlock(&sbi->s_lock);
1282
1283                 ext2_write_super(sb);
1284
1285                 dquot_resume(sb, -1);
1286         }
1287
1288         return 0;
1289 restore_opts:
1290         sbi->s_mount_opt = old_opts.s_mount_opt;
1291         sbi->s_resuid = old_opts.s_resuid;
1292         sbi->s_resgid = old_opts.s_resgid;
1293         sb->s_flags = old_sb_flags;
1294         spin_unlock(&sbi->s_lock);
1295         return err;
1296 }
1297
1298 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1299 {
1300         struct super_block *sb = dentry->d_sb;
1301         struct ext2_sb_info *sbi = EXT2_SB(sb);
1302         struct ext2_super_block *es = sbi->s_es;
1303         u64 fsid;
1304
1305         spin_lock(&sbi->s_lock);
1306
1307         if (test_opt (sb, MINIX_DF))
1308                 sbi->s_overhead_last = 0;
1309         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1310                 unsigned long i, overhead = 0;
1311                 smp_rmb();
1312
1313                 /*
1314                  * Compute the overhead (FS structures). This is constant
1315                  * for a given filesystem unless the number of block groups
1316                  * changes so we cache the previous value until it does.
1317                  */
1318
1319                 /*
1320                  * All of the blocks before first_data_block are
1321                  * overhead
1322                  */
1323                 overhead = le32_to_cpu(es->s_first_data_block);
1324
1325                 /*
1326                  * Add the overhead attributed to the superblock and
1327                  * block group descriptors.  If the sparse superblocks
1328                  * feature is turned on, then not all groups have this.
1329                  */
1330                 for (i = 0; i < sbi->s_groups_count; i++)
1331                         overhead += ext2_bg_has_super(sb, i) +
1332                                 ext2_bg_num_gdb(sb, i);
1333
1334                 /*
1335                  * Every block group has an inode bitmap, a block
1336                  * bitmap, and an inode table.
1337                  */
1338                 overhead += (sbi->s_groups_count *
1339                              (2 + sbi->s_itb_per_group));
1340                 sbi->s_overhead_last = overhead;
1341                 smp_wmb();
1342                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1343         }
1344
1345         buf->f_type = EXT2_SUPER_MAGIC;
1346         buf->f_bsize = sb->s_blocksize;
1347         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1348         buf->f_bfree = ext2_count_free_blocks(sb);
1349         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1350         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1351         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1352                 buf->f_bavail = 0;
1353         buf->f_files = le32_to_cpu(es->s_inodes_count);
1354         buf->f_ffree = ext2_count_free_inodes(sb);
1355         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1356         buf->f_namelen = EXT2_NAME_LEN;
1357         fsid = le64_to_cpup((void *)es->s_uuid) ^
1358                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1359         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1360         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1361         spin_unlock(&sbi->s_lock);
1362         return 0;
1363 }
1364
1365 static int ext2_get_sb(struct file_system_type *fs_type,
1366         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1367 {
1368         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1369 }
1370
1371 #ifdef CONFIG_QUOTA
1372
1373 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1374  * acquiring the locks... As quota files are never truncated and quota code
1375  * itself serializes the operations (and noone else should touch the files)
1376  * we don't have to be afraid of races */
1377 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1378                                size_t len, loff_t off)
1379 {
1380         struct inode *inode = sb_dqopt(sb)->files[type];
1381         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1382         int err = 0;
1383         int offset = off & (sb->s_blocksize - 1);
1384         int tocopy;
1385         size_t toread;
1386         struct buffer_head tmp_bh;
1387         struct buffer_head *bh;
1388         loff_t i_size = i_size_read(inode);
1389
1390         if (off > i_size)
1391                 return 0;
1392         if (off+len > i_size)
1393                 len = i_size-off;
1394         toread = len;
1395         while (toread > 0) {
1396                 tocopy = sb->s_blocksize - offset < toread ?
1397                                 sb->s_blocksize - offset : toread;
1398
1399                 tmp_bh.b_state = 0;
1400                 tmp_bh.b_size = sb->s_blocksize;
1401                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1402                 if (err < 0)
1403                         return err;
1404                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1405                         memset(data, 0, tocopy);
1406                 else {
1407                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1408                         if (!bh)
1409                                 return -EIO;
1410                         memcpy(data, bh->b_data+offset, tocopy);
1411                         brelse(bh);
1412                 }
1413                 offset = 0;
1414                 toread -= tocopy;
1415                 data += tocopy;
1416                 blk++;
1417         }
1418         return len;
1419 }
1420
1421 /* Write to quotafile */
1422 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1423                                 const char *data, size_t len, loff_t off)
1424 {
1425         struct inode *inode = sb_dqopt(sb)->files[type];
1426         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1427         int err = 0;
1428         int offset = off & (sb->s_blocksize - 1);
1429         int tocopy;
1430         size_t towrite = len;
1431         struct buffer_head tmp_bh;
1432         struct buffer_head *bh;
1433
1434         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1435         while (towrite > 0) {
1436                 tocopy = sb->s_blocksize - offset < towrite ?
1437                                 sb->s_blocksize - offset : towrite;
1438
1439                 tmp_bh.b_state = 0;
1440                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1441                 if (err < 0)
1442                         goto out;
1443                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1444                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1445                 else
1446                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1447                 if (!bh) {
1448                         err = -EIO;
1449                         goto out;
1450                 }
1451                 lock_buffer(bh);
1452                 memcpy(bh->b_data+offset, data, tocopy);
1453                 flush_dcache_page(bh->b_page);
1454                 set_buffer_uptodate(bh);
1455                 mark_buffer_dirty(bh);
1456                 unlock_buffer(bh);
1457                 brelse(bh);
1458                 offset = 0;
1459                 towrite -= tocopy;
1460                 data += tocopy;
1461                 blk++;
1462         }
1463 out:
1464         if (len == towrite) {
1465                 mutex_unlock(&inode->i_mutex);
1466                 return err;
1467         }
1468         if (inode->i_size < off+len-towrite)
1469                 i_size_write(inode, off+len-towrite);
1470         inode->i_version++;
1471         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1472         mark_inode_dirty(inode);
1473         mutex_unlock(&inode->i_mutex);
1474         return len - towrite;
1475 }
1476
1477 #endif
1478
1479 static struct file_system_type ext2_fs_type = {
1480         .owner          = THIS_MODULE,
1481         .name           = "ext2",
1482         .get_sb         = ext2_get_sb,
1483         .kill_sb        = kill_block_super,
1484         .fs_flags       = FS_REQUIRES_DEV,
1485 };
1486
1487 static int __init init_ext2_fs(void)
1488 {
1489         int err = init_ext2_xattr();
1490         if (err)
1491                 return err;
1492         err = init_inodecache();
1493         if (err)
1494                 goto out1;
1495         err = register_filesystem(&ext2_fs_type);
1496         if (err)
1497                 goto out;
1498         return 0;
1499 out:
1500         destroy_inodecache();
1501 out1:
1502         exit_ext2_xattr();
1503         return err;
1504 }
1505
1506 static void __exit exit_ext2_fs(void)
1507 {
1508         unregister_filesystem(&ext2_fs_type);
1509         destroy_inodecache();
1510         exit_ext2_xattr();
1511 }
1512
1513 module_init(init_ext2_fs)
1514 module_exit(exit_ext2_fs)