ext2: Unify log messages in ext2
[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/smp_lock.h>
30 #include <linux/vfs.h>
31 #include <linux/seq_file.h>
32 #include <linux/mount.h>
33 #include <linux/log2.h>
34 #include <linux/quotaops.h>
35 #include <asm/uaccess.h>
36 #include "ext2.h"
37 #include "xattr.h"
38 #include "acl.h"
39 #include "xip.h"
40
41 static void ext2_sync_super(struct super_block *sb,
42                             struct ext2_super_block *es);
43 static int ext2_remount (struct super_block * sb, int * flags, char * data);
44 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
45 static int ext2_sync_fs(struct super_block *sb, int wait);
46
47 void ext2_error (struct super_block * sb, const char * function,
48                  const char * fmt, ...)
49 {
50         va_list args;
51         struct ext2_sb_info *sbi = EXT2_SB(sb);
52         struct ext2_super_block *es = sbi->s_es;
53
54         if (!(sb->s_flags & MS_RDONLY)) {
55                 sbi->s_mount_state |= EXT2_ERROR_FS;
56                 es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
57                 ext2_sync_super(sb, es);
58         }
59
60         va_start(args, fmt);
61         printk(KERN_CRIT "EXT2-fs (%s): error: %s: ", sb->s_id, function);
62         vprintk(fmt, args);
63         printk("\n");
64         va_end(args);
65
66         if (test_opt(sb, ERRORS_PANIC))
67                 panic("EXT2-fs: panic from previous error\n");
68         if (test_opt(sb, ERRORS_RO)) {
69                 ext2_msg(sb, KERN_CRIT,
70                              "error: remounting filesystem read-only");
71                 sb->s_flags |= MS_RDONLY;
72         }
73 }
74
75 void ext2_msg(struct super_block *sb, const char *prefix,
76                 const char *fmt, ...)
77 {
78         va_list args;
79
80         va_start(args, fmt);
81         printk("%sEXT2-fs (%s): ", prefix, sb->s_id);
82         vprintk(fmt, args);
83         printk("\n");
84         va_end(args);
85 }
86
87 void ext2_update_dynamic_rev(struct super_block *sb)
88 {
89         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
90
91         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
92                 return;
93
94         ext2_msg(sb, KERN_WARNING,
95                      "warning: updating to rev %d because of "
96                      "new feature flag, running e2fsck is recommended",
97                      EXT2_DYNAMIC_REV);
98
99         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
100         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
101         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
102         /* leave es->s_feature_*compat flags alone */
103         /* es->s_uuid will be set by e2fsck if empty */
104
105         /*
106          * The rest of the superblock fields should be zero, and if not it
107          * means they are likely already in use, so leave them alone.  We
108          * can leave it up to e2fsck to clean up any inconsistencies there.
109          */
110 }
111
112 static void ext2_put_super (struct super_block * sb)
113 {
114         int db_count;
115         int i;
116         struct ext2_sb_info *sbi = EXT2_SB(sb);
117
118         lock_kernel();
119
120         if (sb->s_dirt)
121                 ext2_write_super(sb);
122
123         ext2_xattr_put_super(sb);
124         if (!(sb->s_flags & MS_RDONLY)) {
125                 struct ext2_super_block *es = sbi->s_es;
126
127                 es->s_state = cpu_to_le16(sbi->s_mount_state);
128                 ext2_sync_super(sb, es);
129         }
130         db_count = sbi->s_gdb_count;
131         for (i = 0; i < db_count; i++)
132                 if (sbi->s_group_desc[i])
133                         brelse (sbi->s_group_desc[i]);
134         kfree(sbi->s_group_desc);
135         kfree(sbi->s_debts);
136         percpu_counter_destroy(&sbi->s_freeblocks_counter);
137         percpu_counter_destroy(&sbi->s_freeinodes_counter);
138         percpu_counter_destroy(&sbi->s_dirs_counter);
139         brelse (sbi->s_sbh);
140         sb->s_fs_info = NULL;
141         kfree(sbi->s_blockgroup_lock);
142         kfree(sbi);
143
144         unlock_kernel();
145 }
146
147 static struct kmem_cache * ext2_inode_cachep;
148
149 static struct inode *ext2_alloc_inode(struct super_block *sb)
150 {
151         struct ext2_inode_info *ei;
152         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
153         if (!ei)
154                 return NULL;
155         ei->i_block_alloc_info = NULL;
156         ei->vfs_inode.i_version = 1;
157         return &ei->vfs_inode;
158 }
159
160 static void ext2_destroy_inode(struct inode *inode)
161 {
162         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
163 }
164
165 static void init_once(void *foo)
166 {
167         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
168
169         rwlock_init(&ei->i_meta_lock);
170 #ifdef CONFIG_EXT2_FS_XATTR
171         init_rwsem(&ei->xattr_sem);
172 #endif
173         mutex_init(&ei->truncate_mutex);
174         inode_init_once(&ei->vfs_inode);
175 }
176
177 static int init_inodecache(void)
178 {
179         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
180                                              sizeof(struct ext2_inode_info),
181                                              0, (SLAB_RECLAIM_ACCOUNT|
182                                                 SLAB_MEM_SPREAD),
183                                              init_once);
184         if (ext2_inode_cachep == NULL)
185                 return -ENOMEM;
186         return 0;
187 }
188
189 static void destroy_inodecache(void)
190 {
191         kmem_cache_destroy(ext2_inode_cachep);
192 }
193
194 static void ext2_clear_inode(struct inode *inode)
195 {
196         struct ext2_block_alloc_info *rsv = EXT2_I(inode)->i_block_alloc_info;
197         ext2_discard_reservation(inode);
198         EXT2_I(inode)->i_block_alloc_info = NULL;
199         if (unlikely(rsv))
200                 kfree(rsv);
201 }
202
203 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
204 {
205         struct super_block *sb = vfs->mnt_sb;
206         struct ext2_sb_info *sbi = EXT2_SB(sb);
207         struct ext2_super_block *es = sbi->s_es;
208         unsigned long def_mount_opts;
209
210         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
211
212         if (sbi->s_sb_block != 1)
213                 seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
214         if (test_opt(sb, MINIX_DF))
215                 seq_puts(seq, ",minixdf");
216         if (test_opt(sb, GRPID))
217                 seq_puts(seq, ",grpid");
218         if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
219                 seq_puts(seq, ",nogrpid");
220         if (sbi->s_resuid != EXT2_DEF_RESUID ||
221             le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
222                 seq_printf(seq, ",resuid=%u", sbi->s_resuid);
223         }
224         if (sbi->s_resgid != EXT2_DEF_RESGID ||
225             le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
226                 seq_printf(seq, ",resgid=%u", sbi->s_resgid);
227         }
228         if (test_opt(sb, ERRORS_RO)) {
229                 int def_errors = le16_to_cpu(es->s_errors);
230
231                 if (def_errors == EXT2_ERRORS_PANIC ||
232                     def_errors == EXT2_ERRORS_CONTINUE) {
233                         seq_puts(seq, ",errors=remount-ro");
234                 }
235         }
236         if (test_opt(sb, ERRORS_CONT))
237                 seq_puts(seq, ",errors=continue");
238         if (test_opt(sb, ERRORS_PANIC))
239                 seq_puts(seq, ",errors=panic");
240         if (test_opt(sb, NO_UID32))
241                 seq_puts(seq, ",nouid32");
242         if (test_opt(sb, DEBUG))
243                 seq_puts(seq, ",debug");
244         if (test_opt(sb, OLDALLOC))
245                 seq_puts(seq, ",oldalloc");
246
247 #ifdef CONFIG_EXT2_FS_XATTR
248         if (test_opt(sb, XATTR_USER))
249                 seq_puts(seq, ",user_xattr");
250         if (!test_opt(sb, XATTR_USER) &&
251             (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
252                 seq_puts(seq, ",nouser_xattr");
253         }
254 #endif
255
256 #ifdef CONFIG_EXT2_FS_POSIX_ACL
257         if (test_opt(sb, POSIX_ACL))
258                 seq_puts(seq, ",acl");
259         if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
260                 seq_puts(seq, ",noacl");
261 #endif
262
263         if (test_opt(sb, NOBH))
264                 seq_puts(seq, ",nobh");
265
266 #if defined(CONFIG_QUOTA)
267         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
268                 seq_puts(seq, ",usrquota");
269
270         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
271                 seq_puts(seq, ",grpquota");
272 #endif
273
274 #if defined(CONFIG_EXT2_FS_XIP)
275         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
276                 seq_puts(seq, ",xip");
277 #endif
278
279         if (!test_opt(sb, RESERVATION))
280                 seq_puts(seq, ",noreservation");
281
282         return 0;
283 }
284
285 #ifdef CONFIG_QUOTA
286 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
287 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
288 #endif
289
290 static const struct super_operations ext2_sops = {
291         .alloc_inode    = ext2_alloc_inode,
292         .destroy_inode  = ext2_destroy_inode,
293         .write_inode    = ext2_write_inode,
294         .delete_inode   = ext2_delete_inode,
295         .put_super      = ext2_put_super,
296         .write_super    = ext2_write_super,
297         .sync_fs        = ext2_sync_fs,
298         .statfs         = ext2_statfs,
299         .remount_fs     = ext2_remount,
300         .clear_inode    = ext2_clear_inode,
301         .show_options   = ext2_show_options,
302 #ifdef CONFIG_QUOTA
303         .quota_read     = ext2_quota_read,
304         .quota_write    = ext2_quota_write,
305 #endif
306 };
307
308 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
309                 u64 ino, u32 generation)
310 {
311         struct inode *inode;
312
313         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
314                 return ERR_PTR(-ESTALE);
315         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
316                 return ERR_PTR(-ESTALE);
317
318         /* iget isn't really right if the inode is currently unallocated!!
319          * ext2_read_inode currently does appropriate checks, but
320          * it might be "neater" to call ext2_get_inode first and check
321          * if the inode is valid.....
322          */
323         inode = ext2_iget(sb, ino);
324         if (IS_ERR(inode))
325                 return ERR_CAST(inode);
326         if (generation && inode->i_generation != generation) {
327                 /* we didn't find the right inode.. */
328                 iput(inode);
329                 return ERR_PTR(-ESTALE);
330         }
331         return inode;
332 }
333
334 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
335                 int fh_len, int fh_type)
336 {
337         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
338                                     ext2_nfs_get_inode);
339 }
340
341 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
342                 int fh_len, int fh_type)
343 {
344         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
345                                     ext2_nfs_get_inode);
346 }
347
348 /* Yes, most of these are left as NULL!!
349  * A NULL value implies the default, which works with ext2-like file
350  * systems, but can be improved upon.
351  * Currently only get_parent is required.
352  */
353 static const struct export_operations ext2_export_ops = {
354         .fh_to_dentry = ext2_fh_to_dentry,
355         .fh_to_parent = ext2_fh_to_parent,
356         .get_parent = ext2_get_parent,
357 };
358
359 static unsigned long get_sb_block(void **data)
360 {
361         unsigned long   sb_block;
362         char            *options = (char *) *data;
363
364         if (!options || strncmp(options, "sb=", 3) != 0)
365                 return 1;       /* Default location */
366         options += 3;
367         sb_block = simple_strtoul(options, &options, 0);
368         if (*options && *options != ',') {
369                 printk("EXT2-fs: Invalid sb specification: %s\n",
370                        (char *) *data);
371                 return 1;
372         }
373         if (*options == ',')
374                 options++;
375         *data = (void *) options;
376         return sb_block;
377 }
378
379 enum {
380         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
381         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
382         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
383         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
384         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
385         Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
386 };
387
388 static const match_table_t tokens = {
389         {Opt_bsd_df, "bsddf"},
390         {Opt_minix_df, "minixdf"},
391         {Opt_grpid, "grpid"},
392         {Opt_grpid, "bsdgroups"},
393         {Opt_nogrpid, "nogrpid"},
394         {Opt_nogrpid, "sysvgroups"},
395         {Opt_resgid, "resgid=%u"},
396         {Opt_resuid, "resuid=%u"},
397         {Opt_sb, "sb=%u"},
398         {Opt_err_cont, "errors=continue"},
399         {Opt_err_panic, "errors=panic"},
400         {Opt_err_ro, "errors=remount-ro"},
401         {Opt_nouid32, "nouid32"},
402         {Opt_nocheck, "check=none"},
403         {Opt_nocheck, "nocheck"},
404         {Opt_debug, "debug"},
405         {Opt_oldalloc, "oldalloc"},
406         {Opt_orlov, "orlov"},
407         {Opt_nobh, "nobh"},
408         {Opt_user_xattr, "user_xattr"},
409         {Opt_nouser_xattr, "nouser_xattr"},
410         {Opt_acl, "acl"},
411         {Opt_noacl, "noacl"},
412         {Opt_xip, "xip"},
413         {Opt_grpquota, "grpquota"},
414         {Opt_ignore, "noquota"},
415         {Opt_quota, "quota"},
416         {Opt_usrquota, "usrquota"},
417         {Opt_reservation, "reservation"},
418         {Opt_noreservation, "noreservation"},
419         {Opt_err, NULL}
420 };
421
422 static int parse_options(char *options, struct super_block *sb)
423 {
424         char *p;
425         struct ext2_sb_info *sbi = EXT2_SB(sb);
426         substring_t args[MAX_OPT_ARGS];
427         int option;
428
429         if (!options)
430                 return 1;
431
432         while ((p = strsep (&options, ",")) != NULL) {
433                 int token;
434                 if (!*p)
435                         continue;
436
437                 token = match_token(p, tokens, args);
438                 switch (token) {
439                 case Opt_bsd_df:
440                         clear_opt (sbi->s_mount_opt, MINIX_DF);
441                         break;
442                 case Opt_minix_df:
443                         set_opt (sbi->s_mount_opt, MINIX_DF);
444                         break;
445                 case Opt_grpid:
446                         set_opt (sbi->s_mount_opt, GRPID);
447                         break;
448                 case Opt_nogrpid:
449                         clear_opt (sbi->s_mount_opt, GRPID);
450                         break;
451                 case Opt_resuid:
452                         if (match_int(&args[0], &option))
453                                 return 0;
454                         sbi->s_resuid = option;
455                         break;
456                 case Opt_resgid:
457                         if (match_int(&args[0], &option))
458                                 return 0;
459                         sbi->s_resgid = option;
460                         break;
461                 case Opt_sb:
462                         /* handled by get_sb_block() instead of here */
463                         /* *sb_block = match_int(&args[0]); */
464                         break;
465                 case Opt_err_panic:
466                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
467                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
468                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
469                         break;
470                 case Opt_err_ro:
471                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
472                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
473                         set_opt (sbi->s_mount_opt, ERRORS_RO);
474                         break;
475                 case Opt_err_cont:
476                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
477                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
478                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
479                         break;
480                 case Opt_nouid32:
481                         set_opt (sbi->s_mount_opt, NO_UID32);
482                         break;
483                 case Opt_nocheck:
484                         clear_opt (sbi->s_mount_opt, CHECK);
485                         break;
486                 case Opt_debug:
487                         set_opt (sbi->s_mount_opt, DEBUG);
488                         break;
489                 case Opt_oldalloc:
490                         set_opt (sbi->s_mount_opt, OLDALLOC);
491                         break;
492                 case Opt_orlov:
493                         clear_opt (sbi->s_mount_opt, OLDALLOC);
494                         break;
495                 case Opt_nobh:
496                         set_opt (sbi->s_mount_opt, NOBH);
497                         break;
498 #ifdef CONFIG_EXT2_FS_XATTR
499                 case Opt_user_xattr:
500                         set_opt (sbi->s_mount_opt, XATTR_USER);
501                         break;
502                 case Opt_nouser_xattr:
503                         clear_opt (sbi->s_mount_opt, XATTR_USER);
504                         break;
505 #else
506                 case Opt_user_xattr:
507                 case Opt_nouser_xattr:
508                         ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
509                                 "not supported");
510                         break;
511 #endif
512 #ifdef CONFIG_EXT2_FS_POSIX_ACL
513                 case Opt_acl:
514                         set_opt(sbi->s_mount_opt, POSIX_ACL);
515                         break;
516                 case Opt_noacl:
517                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
518                         break;
519 #else
520                 case Opt_acl:
521                 case Opt_noacl:
522                         ext2_msg(sb, KERN_INFO,
523                                 "(no)acl options not supported");
524                         break;
525 #endif
526                 case Opt_xip:
527 #ifdef CONFIG_EXT2_FS_XIP
528                         set_opt (sbi->s_mount_opt, XIP);
529 #else
530                         ext2_msg(sb, KERN_INFO, "xip option not supported");
531 #endif
532                         break;
533
534 #if defined(CONFIG_QUOTA)
535                 case Opt_quota:
536                 case Opt_usrquota:
537                         set_opt(sbi->s_mount_opt, USRQUOTA);
538                         break;
539
540                 case Opt_grpquota:
541                         set_opt(sbi->s_mount_opt, GRPQUOTA);
542                         break;
543 #else
544                 case Opt_quota:
545                 case Opt_usrquota:
546                 case Opt_grpquota:
547                         ext2_msg(sb, KERN_INFO,
548                                 "quota operations not supported");
549                         break;
550 #endif
551
552                 case Opt_reservation:
553                         set_opt(sbi->s_mount_opt, RESERVATION);
554                         ext2_msg(sb, KERN_INFO, "reservations ON");
555                         break;
556                 case Opt_noreservation:
557                         clear_opt(sbi->s_mount_opt, RESERVATION);
558                         ext2_msg(sb, KERN_INFO, "reservations OFF");
559                         break;
560                 case Opt_ignore:
561                         break;
562                 default:
563                         return 0;
564                 }
565         }
566         return 1;
567 }
568
569 static int ext2_setup_super (struct super_block * sb,
570                               struct ext2_super_block * es,
571                               int read_only)
572 {
573         int res = 0;
574         struct ext2_sb_info *sbi = EXT2_SB(sb);
575
576         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
577                 ext2_msg(sb, KERN_ERR,
578                         "error: revision level too high, "
579                         "forcing read-only mode");
580                 res = MS_RDONLY;
581         }
582         if (read_only)
583                 return res;
584         if (!(sbi->s_mount_state & EXT2_VALID_FS))
585                 ext2_msg(sb, KERN_WARNING,
586                         "warning: mounting unchecked fs, "
587                         "running e2fsck is recommended");
588         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
589                 ext2_msg(sb, KERN_WARNING,
590                         "warning: mounting fs with errors, "
591                         "running e2fsck is recommended");
592         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
593                  le16_to_cpu(es->s_mnt_count) >=
594                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
595                 ext2_msg(sb, KERN_WARNING,
596                         "warning: maximal mount count reached, "
597                         "running e2fsck is recommended");
598         else if (le32_to_cpu(es->s_checkinterval) &&
599                 (le32_to_cpu(es->s_lastcheck) +
600                         le32_to_cpu(es->s_checkinterval) <= get_seconds()))
601                 ext2_msg(sb, KERN_WARNING,
602                         "warning: checktime reached, "
603                         "running e2fsck is recommended");
604         if (!le16_to_cpu(es->s_max_mnt_count))
605                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
606         le16_add_cpu(&es->s_mnt_count, 1);
607         ext2_write_super(sb);
608         if (test_opt (sb, DEBUG))
609                 ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
610                         "bpg=%lu, ipg=%lu, mo=%04lx]",
611                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
612                         sbi->s_frag_size,
613                         sbi->s_groups_count,
614                         EXT2_BLOCKS_PER_GROUP(sb),
615                         EXT2_INODES_PER_GROUP(sb),
616                         sbi->s_mount_opt);
617         return res;
618 }
619
620 static int ext2_check_descriptors(struct super_block *sb)
621 {
622         int i;
623         struct ext2_sb_info *sbi = EXT2_SB(sb);
624
625         ext2_debug ("Checking group descriptors");
626
627         for (i = 0; i < sbi->s_groups_count; i++) {
628                 struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
629                 ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
630                 ext2_fsblk_t last_block;
631
632                 if (i == sbi->s_groups_count - 1)
633                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
634                 else
635                         last_block = first_block +
636                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
637
638                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
639                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
640                 {
641                         ext2_error (sb, "ext2_check_descriptors",
642                                     "Block bitmap for group %d"
643                                     " not in group (block %lu)!",
644                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
645                         return 0;
646                 }
647                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
648                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
649                 {
650                         ext2_error (sb, "ext2_check_descriptors",
651                                     "Inode bitmap for group %d"
652                                     " not in group (block %lu)!",
653                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
654                         return 0;
655                 }
656                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
657                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
658                     last_block)
659                 {
660                         ext2_error (sb, "ext2_check_descriptors",
661                                     "Inode table for group %d"
662                                     " not in group (block %lu)!",
663                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
664                         return 0;
665                 }
666         }
667         return 1;
668 }
669
670 /*
671  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
672  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
673  * We need to be 1 filesystem block less than the 2^32 sector limit.
674  */
675 static loff_t ext2_max_size(int bits)
676 {
677         loff_t res = EXT2_NDIR_BLOCKS;
678         int meta_blocks;
679         loff_t upper_limit;
680
681         /* This is calculated to be the largest file size for a
682          * dense, file such that the total number of
683          * sectors in the file, including data and all indirect blocks,
684          * does not exceed 2^32 -1
685          * __u32 i_blocks representing the total number of
686          * 512 bytes blocks of the file
687          */
688         upper_limit = (1LL << 32) - 1;
689
690         /* total blocks in file system block size */
691         upper_limit >>= (bits - 9);
692
693
694         /* indirect blocks */
695         meta_blocks = 1;
696         /* double indirect blocks */
697         meta_blocks += 1 + (1LL << (bits-2));
698         /* tripple indirect blocks */
699         meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
700
701         upper_limit -= meta_blocks;
702         upper_limit <<= bits;
703
704         res += 1LL << (bits-2);
705         res += 1LL << (2*(bits-2));
706         res += 1LL << (3*(bits-2));
707         res <<= bits;
708         if (res > upper_limit)
709                 res = upper_limit;
710
711         if (res > MAX_LFS_FILESIZE)
712                 res = MAX_LFS_FILESIZE;
713
714         return res;
715 }
716
717 static unsigned long descriptor_loc(struct super_block *sb,
718                                     unsigned long logic_sb_block,
719                                     int nr)
720 {
721         struct ext2_sb_info *sbi = EXT2_SB(sb);
722         unsigned long bg, first_meta_bg;
723         int has_super = 0;
724         
725         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
726
727         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
728             nr < first_meta_bg)
729                 return (logic_sb_block + nr + 1);
730         bg = sbi->s_desc_per_block * nr;
731         if (ext2_bg_has_super(sb, bg))
732                 has_super = 1;
733
734         return ext2_group_first_block_no(sb, bg) + has_super;
735 }
736
737 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
738 {
739         struct buffer_head * bh;
740         struct ext2_sb_info * sbi;
741         struct ext2_super_block * es;
742         struct inode *root;
743         unsigned long block;
744         unsigned long sb_block = get_sb_block(&data);
745         unsigned long logic_sb_block;
746         unsigned long offset = 0;
747         unsigned long def_mount_opts;
748         long ret = -EINVAL;
749         int blocksize = BLOCK_SIZE;
750         int db_count;
751         int i, j;
752         __le32 features;
753         int err;
754
755         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
756         if (!sbi)
757                 return -ENOMEM;
758
759         sbi->s_blockgroup_lock =
760                 kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
761         if (!sbi->s_blockgroup_lock) {
762                 kfree(sbi);
763                 return -ENOMEM;
764         }
765         sb->s_fs_info = sbi;
766         sbi->s_sb_block = sb_block;
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         root = ext2_iget(sb, EXT2_ROOT_INO);
1060         if (IS_ERR(root)) {
1061                 ret = PTR_ERR(root);
1062                 goto failed_mount3;
1063         }
1064         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1065                 iput(root);
1066                 ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1067                 goto failed_mount3;
1068         }
1069
1070         sb->s_root = d_alloc_root(root);
1071         if (!sb->s_root) {
1072                 iput(root);
1073                 ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1074                 ret = -ENOMEM;
1075                 goto failed_mount3;
1076         }
1077         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1078                 ext2_msg(sb, KERN_WARNING,
1079                         "warning: mounting ext3 filesystem as ext2");
1080         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
1081         return 0;
1082
1083 cantfind_ext2:
1084         if (!silent)
1085                 ext2_msg(sb, KERN_ERR,
1086                         "error: can't find an ext2 filesystem on dev %s.",
1087                         sb->s_id);
1088         goto failed_mount;
1089 failed_mount3:
1090         percpu_counter_destroy(&sbi->s_freeblocks_counter);
1091         percpu_counter_destroy(&sbi->s_freeinodes_counter);
1092         percpu_counter_destroy(&sbi->s_dirs_counter);
1093 failed_mount2:
1094         for (i = 0; i < db_count; i++)
1095                 brelse(sbi->s_group_desc[i]);
1096 failed_mount_group_desc:
1097         kfree(sbi->s_group_desc);
1098         kfree(sbi->s_debts);
1099 failed_mount:
1100         brelse(bh);
1101 failed_sbi:
1102         sb->s_fs_info = NULL;
1103         kfree(sbi->s_blockgroup_lock);
1104         kfree(sbi);
1105         return ret;
1106 }
1107
1108 static void ext2_commit_super (struct super_block * sb,
1109                                struct ext2_super_block * es)
1110 {
1111         es->s_wtime = cpu_to_le32(get_seconds());
1112         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1113         sb->s_dirt = 0;
1114 }
1115
1116 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
1117 {
1118         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1119         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1120         es->s_wtime = cpu_to_le32(get_seconds());
1121         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1122         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1123         sb->s_dirt = 0;
1124 }
1125
1126 /*
1127  * In the second extended file system, it is not necessary to
1128  * write the super block since we use a mapping of the
1129  * disk super block in a buffer.
1130  *
1131  * However, this function is still used to set the fs valid
1132  * flags to 0.  We need to set this flag to 0 since the fs
1133  * may have been checked while mounted and e2fsck may have
1134  * set s_state to EXT2_VALID_FS after some corrections.
1135  */
1136
1137 static int ext2_sync_fs(struct super_block *sb, int wait)
1138 {
1139         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1140
1141         lock_kernel();
1142         if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1143                 ext2_debug("setting valid to 0\n");
1144                 es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1145                 es->s_free_blocks_count =
1146                         cpu_to_le32(ext2_count_free_blocks(sb));
1147                 es->s_free_inodes_count =
1148                         cpu_to_le32(ext2_count_free_inodes(sb));
1149                 es->s_mtime = cpu_to_le32(get_seconds());
1150                 ext2_sync_super(sb, es);
1151         } else {
1152                 ext2_commit_super(sb, es);
1153         }
1154         sb->s_dirt = 0;
1155         unlock_kernel();
1156
1157         return 0;
1158 }
1159
1160
1161 void ext2_write_super(struct super_block *sb)
1162 {
1163         if (!(sb->s_flags & MS_RDONLY))
1164                 ext2_sync_fs(sb, 1);
1165         else
1166                 sb->s_dirt = 0;
1167 }
1168
1169 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1170 {
1171         struct ext2_sb_info * sbi = EXT2_SB(sb);
1172         struct ext2_super_block * es;
1173         unsigned long old_mount_opt = sbi->s_mount_opt;
1174         struct ext2_mount_options old_opts;
1175         unsigned long old_sb_flags;
1176         int err;
1177
1178         lock_kernel();
1179
1180         /* Store the old options */
1181         old_sb_flags = sb->s_flags;
1182         old_opts.s_mount_opt = sbi->s_mount_opt;
1183         old_opts.s_resuid = sbi->s_resuid;
1184         old_opts.s_resgid = sbi->s_resgid;
1185
1186         /*
1187          * Allow the "check" option to be passed as a remount option.
1188          */
1189         if (!parse_options(data, sb)) {
1190                 err = -EINVAL;
1191                 goto restore_opts;
1192         }
1193
1194         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1195                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1196
1197         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1198                                     EXT2_MOUNT_XIP if not */
1199
1200         if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1201                 ext2_msg(sb, KERN_WARNING,
1202                         "warning: unsupported blocksize for xip");
1203                 err = -EINVAL;
1204                 goto restore_opts;
1205         }
1206
1207         es = sbi->s_es;
1208         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1209             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1210             invalidate_inodes(sb)) {
1211                 ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1212                          "xip flag with busy inodes while remounting");
1213                 sbi->s_mount_opt &= ~EXT2_MOUNT_XIP;
1214                 sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;
1215         }
1216         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
1217                 unlock_kernel();
1218                 return 0;
1219         }
1220         if (*flags & MS_RDONLY) {
1221                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1222                     !(sbi->s_mount_state & EXT2_VALID_FS)) {
1223                         unlock_kernel();
1224                         return 0;
1225                 }
1226                 /*
1227                  * OK, we are remounting a valid rw partition rdonly, so set
1228                  * the rdonly flag and then mark the partition as valid again.
1229                  */
1230                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1231                 es->s_mtime = cpu_to_le32(get_seconds());
1232         } else {
1233                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1234                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1235                 if (ret) {
1236                         ext2_msg(sb, KERN_WARNING,
1237                                 "warning: couldn't remount RDWR because of "
1238                                 "unsupported optional features (%x).",
1239                                 le32_to_cpu(ret));
1240                         err = -EROFS;
1241                         goto restore_opts;
1242                 }
1243                 /*
1244                  * Mounting a RDONLY partition read-write, so reread and
1245                  * store the current valid flag.  (It may have been changed
1246                  * by e2fsck since we originally mounted the partition.)
1247                  */
1248                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1249                 if (!ext2_setup_super (sb, es, 0))
1250                         sb->s_flags &= ~MS_RDONLY;
1251         }
1252         ext2_sync_super(sb, es);
1253         unlock_kernel();
1254         return 0;
1255 restore_opts:
1256         sbi->s_mount_opt = old_opts.s_mount_opt;
1257         sbi->s_resuid = old_opts.s_resuid;
1258         sbi->s_resgid = old_opts.s_resgid;
1259         sb->s_flags = old_sb_flags;
1260         unlock_kernel();
1261         return err;
1262 }
1263
1264 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1265 {
1266         struct super_block *sb = dentry->d_sb;
1267         struct ext2_sb_info *sbi = EXT2_SB(sb);
1268         struct ext2_super_block *es = sbi->s_es;
1269         u64 fsid;
1270
1271         if (test_opt (sb, MINIX_DF))
1272                 sbi->s_overhead_last = 0;
1273         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1274                 unsigned long i, overhead = 0;
1275                 smp_rmb();
1276
1277                 /*
1278                  * Compute the overhead (FS structures). This is constant
1279                  * for a given filesystem unless the number of block groups
1280                  * changes so we cache the previous value until it does.
1281                  */
1282
1283                 /*
1284                  * All of the blocks before first_data_block are
1285                  * overhead
1286                  */
1287                 overhead = le32_to_cpu(es->s_first_data_block);
1288
1289                 /*
1290                  * Add the overhead attributed to the superblock and
1291                  * block group descriptors.  If the sparse superblocks
1292                  * feature is turned on, then not all groups have this.
1293                  */
1294                 for (i = 0; i < sbi->s_groups_count; i++)
1295                         overhead += ext2_bg_has_super(sb, i) +
1296                                 ext2_bg_num_gdb(sb, i);
1297
1298                 /*
1299                  * Every block group has an inode bitmap, a block
1300                  * bitmap, and an inode table.
1301                  */
1302                 overhead += (sbi->s_groups_count *
1303                              (2 + sbi->s_itb_per_group));
1304                 sbi->s_overhead_last = overhead;
1305                 smp_wmb();
1306                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1307         }
1308
1309         buf->f_type = EXT2_SUPER_MAGIC;
1310         buf->f_bsize = sb->s_blocksize;
1311         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1312         buf->f_bfree = ext2_count_free_blocks(sb);
1313         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1314         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1315         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1316                 buf->f_bavail = 0;
1317         buf->f_files = le32_to_cpu(es->s_inodes_count);
1318         buf->f_ffree = ext2_count_free_inodes(sb);
1319         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1320         buf->f_namelen = EXT2_NAME_LEN;
1321         fsid = le64_to_cpup((void *)es->s_uuid) ^
1322                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1323         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1324         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1325         return 0;
1326 }
1327
1328 static int ext2_get_sb(struct file_system_type *fs_type,
1329         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1330 {
1331         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1332 }
1333
1334 #ifdef CONFIG_QUOTA
1335
1336 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1337  * acquiring the locks... As quota files are never truncated and quota code
1338  * itself serializes the operations (and noone else should touch the files)
1339  * we don't have to be afraid of races */
1340 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1341                                size_t len, loff_t off)
1342 {
1343         struct inode *inode = sb_dqopt(sb)->files[type];
1344         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1345         int err = 0;
1346         int offset = off & (sb->s_blocksize - 1);
1347         int tocopy;
1348         size_t toread;
1349         struct buffer_head tmp_bh;
1350         struct buffer_head *bh;
1351         loff_t i_size = i_size_read(inode);
1352
1353         if (off > i_size)
1354                 return 0;
1355         if (off+len > i_size)
1356                 len = i_size-off;
1357         toread = len;
1358         while (toread > 0) {
1359                 tocopy = sb->s_blocksize - offset < toread ?
1360                                 sb->s_blocksize - offset : toread;
1361
1362                 tmp_bh.b_state = 0;
1363                 tmp_bh.b_size = sb->s_blocksize;
1364                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1365                 if (err < 0)
1366                         return err;
1367                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1368                         memset(data, 0, tocopy);
1369                 else {
1370                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1371                         if (!bh)
1372                                 return -EIO;
1373                         memcpy(data, bh->b_data+offset, tocopy);
1374                         brelse(bh);
1375                 }
1376                 offset = 0;
1377                 toread -= tocopy;
1378                 data += tocopy;
1379                 blk++;
1380         }
1381         return len;
1382 }
1383
1384 /* Write to quotafile */
1385 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1386                                 const char *data, size_t len, loff_t off)
1387 {
1388         struct inode *inode = sb_dqopt(sb)->files[type];
1389         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1390         int err = 0;
1391         int offset = off & (sb->s_blocksize - 1);
1392         int tocopy;
1393         size_t towrite = len;
1394         struct buffer_head tmp_bh;
1395         struct buffer_head *bh;
1396
1397         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1398         while (towrite > 0) {
1399                 tocopy = sb->s_blocksize - offset < towrite ?
1400                                 sb->s_blocksize - offset : towrite;
1401
1402                 tmp_bh.b_state = 0;
1403                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1404                 if (err < 0)
1405                         goto out;
1406                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1407                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1408                 else
1409                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1410                 if (!bh) {
1411                         err = -EIO;
1412                         goto out;
1413                 }
1414                 lock_buffer(bh);
1415                 memcpy(bh->b_data+offset, data, tocopy);
1416                 flush_dcache_page(bh->b_page);
1417                 set_buffer_uptodate(bh);
1418                 mark_buffer_dirty(bh);
1419                 unlock_buffer(bh);
1420                 brelse(bh);
1421                 offset = 0;
1422                 towrite -= tocopy;
1423                 data += tocopy;
1424                 blk++;
1425         }
1426 out:
1427         if (len == towrite) {
1428                 mutex_unlock(&inode->i_mutex);
1429                 return err;
1430         }
1431         if (inode->i_size < off+len-towrite)
1432                 i_size_write(inode, off+len-towrite);
1433         inode->i_version++;
1434         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1435         mark_inode_dirty(inode);
1436         mutex_unlock(&inode->i_mutex);
1437         return len - towrite;
1438 }
1439
1440 #endif
1441
1442 static struct file_system_type ext2_fs_type = {
1443         .owner          = THIS_MODULE,
1444         .name           = "ext2",
1445         .get_sb         = ext2_get_sb,
1446         .kill_sb        = kill_block_super,
1447         .fs_flags       = FS_REQUIRES_DEV,
1448 };
1449
1450 static int __init init_ext2_fs(void)
1451 {
1452         int err = init_ext2_xattr();
1453         if (err)
1454                 return err;
1455         err = init_inodecache();
1456         if (err)
1457                 goto out1;
1458         err = register_filesystem(&ext2_fs_type);
1459         if (err)
1460                 goto out;
1461         return 0;
1462 out:
1463         destroy_inodecache();
1464 out1:
1465         exit_ext2_xattr();
1466         return err;
1467 }
1468
1469 static void __exit exit_ext2_fs(void)
1470 {
1471         unregister_filesystem(&ext2_fs_type);
1472         destroy_inodecache();
1473         exit_ext2_xattr();
1474 }
1475
1476 module_init(init_ext2_fs)
1477 module_exit(exit_ext2_fs)