ext2: fix the outdated comment in ext2_nfs_get_inode()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