Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux...
[pandora-kernel.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         /* iget isn't really right if the inode is currently unallocated!!
331          * ext2_read_inode currently does appropriate checks, but
332          * it might be "neater" to call ext2_get_inode first and check
333          * if the inode is valid.....
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, "error: blocksize is too small");
902                         goto failed_sbi;
903                 }
904
905                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
906                 offset = (sb_block*BLOCK_SIZE) % blocksize;
907                 bh = sb_bread(sb, logic_sb_block);
908                 if(!bh) {
909                         ext2_msg(sb, KERN_ERR, "error: couldn't read"
910                                 "superblock on 2nd try");
911                         goto failed_sbi;
912                 }
913                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
914                 sbi->s_es = es;
915                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
916                         ext2_msg(sb, KERN_ERR, "error: magic mismatch");
917                         goto failed_mount;
918                 }
919         }
920
921         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
922
923         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
924                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
925                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
926         } else {
927                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
928                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
929                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
930                     !is_power_of_2(sbi->s_inode_size) ||
931                     (sbi->s_inode_size > blocksize)) {
932                         ext2_msg(sb, KERN_ERR,
933                                 "error: unsupported inode size: %d",
934                                 sbi->s_inode_size);
935                         goto failed_mount;
936                 }
937         }
938
939         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
940                                    le32_to_cpu(es->s_log_frag_size);
941         if (sbi->s_frag_size == 0)
942                 goto cantfind_ext2;
943         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
944
945         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
946         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
947         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
948
949         if (EXT2_INODE_SIZE(sb) == 0)
950                 goto cantfind_ext2;
951         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
952         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
953                 goto cantfind_ext2;
954         sbi->s_itb_per_group = sbi->s_inodes_per_group /
955                                         sbi->s_inodes_per_block;
956         sbi->s_desc_per_block = sb->s_blocksize /
957                                         sizeof (struct ext2_group_desc);
958         sbi->s_sbh = bh;
959         sbi->s_mount_state = le16_to_cpu(es->s_state);
960         sbi->s_addr_per_block_bits =
961                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
962         sbi->s_desc_per_block_bits =
963                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
964
965         if (sb->s_magic != EXT2_SUPER_MAGIC)
966                 goto cantfind_ext2;
967
968         if (sb->s_blocksize != bh->b_size) {
969                 if (!silent)
970                         ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
971                 goto failed_mount;
972         }
973
974         if (sb->s_blocksize != sbi->s_frag_size) {
975                 ext2_msg(sb, KERN_ERR,
976                         "error: fragsize %lu != blocksize %lu"
977                         "(not supported yet)",
978                         sbi->s_frag_size, sb->s_blocksize);
979                 goto failed_mount;
980         }
981
982         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
983                 ext2_msg(sb, KERN_ERR,
984                         "error: #blocks per group too big: %lu",
985                         sbi->s_blocks_per_group);
986                 goto failed_mount;
987         }
988         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
989                 ext2_msg(sb, KERN_ERR,
990                         "error: #fragments per group too big: %lu",
991                         sbi->s_frags_per_group);
992                 goto failed_mount;
993         }
994         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
995                 ext2_msg(sb, KERN_ERR,
996                         "error: #inodes per group too big: %lu",
997                         sbi->s_inodes_per_group);
998                 goto failed_mount;
999         }
1000
1001         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
1002                 goto cantfind_ext2;
1003         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
1004                                 le32_to_cpu(es->s_first_data_block) - 1)
1005                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
1006         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
1007                    EXT2_DESC_PER_BLOCK(sb);
1008         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
1009         if (sbi->s_group_desc == NULL) {
1010                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
1011                 goto failed_mount;
1012         }
1013         bgl_lock_init(sbi->s_blockgroup_lock);
1014         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1015         if (!sbi->s_debts) {
1016                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
1017                 goto failed_mount_group_desc;
1018         }
1019         for (i = 0; i < db_count; i++) {
1020                 block = descriptor_loc(sb, logic_sb_block, i);
1021                 sbi->s_group_desc[i] = sb_bread(sb, block);
1022                 if (!sbi->s_group_desc[i]) {
1023                         for (j = 0; j < i; j++)
1024                                 brelse (sbi->s_group_desc[j]);
1025                         ext2_msg(sb, KERN_ERR,
1026                                 "error: unable to read group descriptors");
1027                         goto failed_mount_group_desc;
1028                 }
1029         }
1030         if (!ext2_check_descriptors (sb)) {
1031                 ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1032                 goto failed_mount2;
1033         }
1034         sbi->s_gdb_count = db_count;
1035         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1036         spin_lock_init(&sbi->s_next_gen_lock);
1037
1038         /* per fileystem reservation list head & lock */
1039         spin_lock_init(&sbi->s_rsv_window_lock);
1040         sbi->s_rsv_window_root = RB_ROOT;
1041         /*
1042          * Add a single, static dummy reservation to the start of the
1043          * reservation window list --- it gives us a placeholder for
1044          * append-at-start-of-list which makes the allocation logic
1045          * _much_ simpler.
1046          */
1047         sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1048         sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1049         sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1050         sbi->s_rsv_window_head.rsv_goal_size = 0;
1051         ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1052
1053         err = percpu_counter_init(&sbi->s_freeblocks_counter,
1054                                 ext2_count_free_blocks(sb));
1055         if (!err) {
1056                 err = percpu_counter_init(&sbi->s_freeinodes_counter,
1057                                 ext2_count_free_inodes(sb));
1058         }
1059         if (!err) {
1060                 err = percpu_counter_init(&sbi->s_dirs_counter,
1061                                 ext2_count_dirs(sb));
1062         }
1063         if (err) {
1064                 ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1065                 goto failed_mount3;
1066         }
1067         /*
1068          * set up enough so that it can read an inode
1069          */
1070         sb->s_op = &ext2_sops;
1071         sb->s_export_op = &ext2_export_ops;
1072         sb->s_xattr = ext2_xattr_handlers;
1073
1074 #ifdef CONFIG_QUOTA
1075         sb->dq_op = &dquot_operations;
1076         sb->s_qcop = &dquot_quotactl_ops;
1077 #endif
1078
1079         root = ext2_iget(sb, EXT2_ROOT_INO);
1080         if (IS_ERR(root)) {
1081                 ret = PTR_ERR(root);
1082                 goto failed_mount3;
1083         }
1084         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1085                 iput(root);
1086                 ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1087                 goto failed_mount3;
1088         }
1089
1090         sb->s_root = d_alloc_root(root);
1091         if (!sb->s_root) {
1092                 iput(root);
1093                 ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1094                 ret = -ENOMEM;
1095                 goto failed_mount3;
1096         }
1097         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1098                 ext2_msg(sb, KERN_WARNING,
1099                         "warning: mounting ext3 filesystem as ext2");
1100         if (ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY))
1101                 sb->s_flags |= MS_RDONLY;
1102         ext2_write_super(sb);
1103         return 0;
1104
1105 cantfind_ext2:
1106         if (!silent)
1107                 ext2_msg(sb, KERN_ERR,
1108                         "error: can't find an ext2 filesystem on dev %s.",
1109                         sb->s_id);
1110         goto failed_mount;
1111 failed_mount3:
1112         percpu_counter_destroy(&sbi->s_freeblocks_counter);
1113         percpu_counter_destroy(&sbi->s_freeinodes_counter);
1114         percpu_counter_destroy(&sbi->s_dirs_counter);
1115 failed_mount2:
1116         for (i = 0; i < db_count; i++)
1117                 brelse(sbi->s_group_desc[i]);
1118 failed_mount_group_desc:
1119         kfree(sbi->s_group_desc);
1120         kfree(sbi->s_debts);
1121 failed_mount:
1122         brelse(bh);
1123 failed_sbi:
1124         sb->s_fs_info = NULL;
1125         kfree(sbi->s_blockgroup_lock);
1126         kfree(sbi);
1127 failed_unlock:
1128         return ret;
1129 }
1130
1131 static void ext2_clear_super_error(struct super_block *sb)
1132 {
1133         struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1134
1135         if (buffer_write_io_error(sbh)) {
1136                 /*
1137                  * Oh, dear.  A previous attempt to write the
1138                  * superblock failed.  This could happen because the
1139                  * USB device was yanked out.  Or it could happen to
1140                  * be a transient write error and maybe the block will
1141                  * be remapped.  Nothing we can do but to retry the
1142                  * write and hope for the best.
1143                  */
1144                 ext2_msg(sb, KERN_ERR,
1145                        "previous I/O error to superblock detected\n");
1146                 clear_buffer_write_io_error(sbh);
1147                 set_buffer_uptodate(sbh);
1148         }
1149 }
1150
1151 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
1152                             int wait)
1153 {
1154         ext2_clear_super_error(sb);
1155         spin_lock(&EXT2_SB(sb)->s_lock);
1156         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1157         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1158         es->s_wtime = cpu_to_le32(get_seconds());
1159         /* unlock before we do IO */
1160         spin_unlock(&EXT2_SB(sb)->s_lock);
1161         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1162         if (wait)
1163                 sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1164         sb->s_dirt = 0;
1165 }
1166
1167 /*
1168  * In the second extended file system, it is not necessary to
1169  * write the super block since we use a mapping of the
1170  * disk super block in a buffer.
1171  *
1172  * However, this function is still used to set the fs valid
1173  * flags to 0.  We need to set this flag to 0 since the fs
1174  * may have been checked while mounted and e2fsck may have
1175  * set s_state to EXT2_VALID_FS after some corrections.
1176  */
1177 static int ext2_sync_fs(struct super_block *sb, int wait)
1178 {
1179         struct ext2_sb_info *sbi = EXT2_SB(sb);
1180         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1181
1182         spin_lock(&sbi->s_lock);
1183         if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1184                 ext2_debug("setting valid to 0\n");
1185                 es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1186         }
1187         spin_unlock(&sbi->s_lock);
1188         ext2_sync_super(sb, es, wait);
1189         return 0;
1190 }
1191
1192
1193 void ext2_write_super(struct super_block *sb)
1194 {
1195         if (!(sb->s_flags & MS_RDONLY))
1196                 ext2_sync_fs(sb, 1);
1197         else
1198                 sb->s_dirt = 0;
1199 }
1200
1201 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1202 {
1203         struct ext2_sb_info * sbi = EXT2_SB(sb);
1204         struct ext2_super_block * es;
1205         unsigned long old_mount_opt = sbi->s_mount_opt;
1206         struct ext2_mount_options old_opts;
1207         unsigned long old_sb_flags;
1208         int err;
1209
1210         spin_lock(&sbi->s_lock);
1211
1212         /* Store the old options */
1213         old_sb_flags = sb->s_flags;
1214         old_opts.s_mount_opt = sbi->s_mount_opt;
1215         old_opts.s_resuid = sbi->s_resuid;
1216         old_opts.s_resgid = sbi->s_resgid;
1217
1218         /*
1219          * Allow the "check" option to be passed as a remount option.
1220          */
1221         if (!parse_options(data, sb)) {
1222                 err = -EINVAL;
1223                 goto restore_opts;
1224         }
1225
1226         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1227                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1228
1229         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1230                                     EXT2_MOUNT_XIP if not */
1231
1232         if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1233                 ext2_msg(sb, KERN_WARNING,
1234                         "warning: unsupported blocksize for xip");
1235                 err = -EINVAL;
1236                 goto restore_opts;
1237         }
1238
1239         es = sbi->s_es;
1240         if ((sbi->s_mount_opt ^ old_mount_opt) & EXT2_MOUNT_XIP) {
1241                 ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1242                          "xip flag with busy inodes while remounting");
1243                 sbi->s_mount_opt &= ~EXT2_MOUNT_XIP;
1244                 sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;
1245         }
1246         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
1247                 spin_unlock(&sbi->s_lock);
1248                 return 0;
1249         }
1250         if (*flags & MS_RDONLY) {
1251                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1252                     !(sbi->s_mount_state & EXT2_VALID_FS)) {
1253                         spin_unlock(&sbi->s_lock);
1254                         return 0;
1255                 }
1256
1257                 /*
1258                  * OK, we are remounting a valid rw partition rdonly, so set
1259                  * the rdonly flag and then mark the partition as valid again.
1260                  */
1261                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1262                 es->s_mtime = cpu_to_le32(get_seconds());
1263                 spin_unlock(&sbi->s_lock);
1264
1265                 err = dquot_suspend(sb, -1);
1266                 if (err < 0) {
1267                         spin_lock(&sbi->s_lock);
1268                         goto restore_opts;
1269                 }
1270
1271                 ext2_sync_super(sb, es, 1);
1272         } else {
1273                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1274                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1275                 if (ret) {
1276                         ext2_msg(sb, KERN_WARNING,
1277                                 "warning: couldn't remount RDWR because of "
1278                                 "unsupported optional features (%x).",
1279                                 le32_to_cpu(ret));
1280                         err = -EROFS;
1281                         goto restore_opts;
1282                 }
1283                 /*
1284                  * Mounting a RDONLY partition read-write, so reread and
1285                  * store the current valid flag.  (It may have been changed
1286                  * by e2fsck since we originally mounted the partition.)
1287                  */
1288                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1289                 if (!ext2_setup_super (sb, es, 0))
1290                         sb->s_flags &= ~MS_RDONLY;
1291                 spin_unlock(&sbi->s_lock);
1292
1293                 ext2_write_super(sb);
1294
1295                 dquot_resume(sb, -1);
1296         }
1297
1298         return 0;
1299 restore_opts:
1300         sbi->s_mount_opt = old_opts.s_mount_opt;
1301         sbi->s_resuid = old_opts.s_resuid;
1302         sbi->s_resgid = old_opts.s_resgid;
1303         sb->s_flags = old_sb_flags;
1304         spin_unlock(&sbi->s_lock);
1305         return err;
1306 }
1307
1308 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1309 {
1310         struct super_block *sb = dentry->d_sb;
1311         struct ext2_sb_info *sbi = EXT2_SB(sb);
1312         struct ext2_super_block *es = sbi->s_es;
1313         u64 fsid;
1314
1315         spin_lock(&sbi->s_lock);
1316
1317         if (test_opt (sb, MINIX_DF))
1318                 sbi->s_overhead_last = 0;
1319         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1320                 unsigned long i, overhead = 0;
1321                 smp_rmb();
1322
1323                 /*
1324                  * Compute the overhead (FS structures). This is constant
1325                  * for a given filesystem unless the number of block groups
1326                  * changes so we cache the previous value until it does.
1327                  */
1328
1329                 /*
1330                  * All of the blocks before first_data_block are
1331                  * overhead
1332                  */
1333                 overhead = le32_to_cpu(es->s_first_data_block);
1334
1335                 /*
1336                  * Add the overhead attributed to the superblock and
1337                  * block group descriptors.  If the sparse superblocks
1338                  * feature is turned on, then not all groups have this.
1339                  */
1340                 for (i = 0; i < sbi->s_groups_count; i++)
1341                         overhead += ext2_bg_has_super(sb, i) +
1342                                 ext2_bg_num_gdb(sb, i);
1343
1344                 /*
1345                  * Every block group has an inode bitmap, a block
1346                  * bitmap, and an inode table.
1347                  */
1348                 overhead += (sbi->s_groups_count *
1349                              (2 + sbi->s_itb_per_group));
1350                 sbi->s_overhead_last = overhead;
1351                 smp_wmb();
1352                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1353         }
1354
1355         buf->f_type = EXT2_SUPER_MAGIC;
1356         buf->f_bsize = sb->s_blocksize;
1357         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1358         buf->f_bfree = ext2_count_free_blocks(sb);
1359         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1360         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1361         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1362                 buf->f_bavail = 0;
1363         buf->f_files = le32_to_cpu(es->s_inodes_count);
1364         buf->f_ffree = ext2_count_free_inodes(sb);
1365         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1366         buf->f_namelen = EXT2_NAME_LEN;
1367         fsid = le64_to_cpup((void *)es->s_uuid) ^
1368                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1369         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1370         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1371         spin_unlock(&sbi->s_lock);
1372         return 0;
1373 }
1374
1375 static struct dentry *ext2_mount(struct file_system_type *fs_type,
1376         int flags, const char *dev_name, void *data)
1377 {
1378         return mount_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1379 }
1380
1381 #ifdef CONFIG_QUOTA
1382
1383 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1384  * acquiring the locks... As quota files are never truncated and quota code
1385  * itself serializes the operations (and noone else should touch the files)
1386  * we don't have to be afraid of races */
1387 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1388                                size_t len, loff_t off)
1389 {
1390         struct inode *inode = sb_dqopt(sb)->files[type];
1391         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1392         int err = 0;
1393         int offset = off & (sb->s_blocksize - 1);
1394         int tocopy;
1395         size_t toread;
1396         struct buffer_head tmp_bh;
1397         struct buffer_head *bh;
1398         loff_t i_size = i_size_read(inode);
1399
1400         if (off > i_size)
1401                 return 0;
1402         if (off+len > i_size)
1403                 len = i_size-off;
1404         toread = len;
1405         while (toread > 0) {
1406                 tocopy = sb->s_blocksize - offset < toread ?
1407                                 sb->s_blocksize - offset : toread;
1408
1409                 tmp_bh.b_state = 0;
1410                 tmp_bh.b_size = sb->s_blocksize;
1411                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1412                 if (err < 0)
1413                         return err;
1414                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1415                         memset(data, 0, tocopy);
1416                 else {
1417                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1418                         if (!bh)
1419                                 return -EIO;
1420                         memcpy(data, bh->b_data+offset, tocopy);
1421                         brelse(bh);
1422                 }
1423                 offset = 0;
1424                 toread -= tocopy;
1425                 data += tocopy;
1426                 blk++;
1427         }
1428         return len;
1429 }
1430
1431 /* Write to quotafile */
1432 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1433                                 const char *data, size_t len, loff_t off)
1434 {
1435         struct inode *inode = sb_dqopt(sb)->files[type];
1436         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1437         int err = 0;
1438         int offset = off & (sb->s_blocksize - 1);
1439         int tocopy;
1440         size_t towrite = len;
1441         struct buffer_head tmp_bh;
1442         struct buffer_head *bh;
1443
1444         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1445         while (towrite > 0) {
1446                 tocopy = sb->s_blocksize - offset < towrite ?
1447                                 sb->s_blocksize - offset : towrite;
1448
1449                 tmp_bh.b_state = 0;
1450                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1451                 if (err < 0)
1452                         goto out;
1453                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1454                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1455                 else
1456                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1457                 if (!bh) {
1458                         err = -EIO;
1459                         goto out;
1460                 }
1461                 lock_buffer(bh);
1462                 memcpy(bh->b_data+offset, data, tocopy);
1463                 flush_dcache_page(bh->b_page);
1464                 set_buffer_uptodate(bh);
1465                 mark_buffer_dirty(bh);
1466                 unlock_buffer(bh);
1467                 brelse(bh);
1468                 offset = 0;
1469                 towrite -= tocopy;
1470                 data += tocopy;
1471                 blk++;
1472         }
1473 out:
1474         if (len == towrite) {
1475                 mutex_unlock(&inode->i_mutex);
1476                 return err;
1477         }
1478         if (inode->i_size < off+len-towrite)
1479                 i_size_write(inode, off+len-towrite);
1480         inode->i_version++;
1481         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1482         mark_inode_dirty(inode);
1483         mutex_unlock(&inode->i_mutex);
1484         return len - towrite;
1485 }
1486
1487 #endif
1488
1489 static struct file_system_type ext2_fs_type = {
1490         .owner          = THIS_MODULE,
1491         .name           = "ext2",
1492         .mount          = ext2_mount,
1493         .kill_sb        = kill_block_super,
1494         .fs_flags       = FS_REQUIRES_DEV,
1495 };
1496
1497 static int __init init_ext2_fs(void)
1498 {
1499         int err = init_ext2_xattr();
1500         if (err)
1501                 return err;
1502         err = init_inodecache();
1503         if (err)
1504                 goto out1;
1505         err = register_filesystem(&ext2_fs_type);
1506         if (err)
1507                 goto out;
1508         return 0;
1509 out:
1510         destroy_inodecache();
1511 out1:
1512         exit_ext2_xattr();
1513         return err;
1514 }
1515
1516 static void __exit exit_ext2_fs(void)
1517 {
1518         unregister_filesystem(&ext2_fs_type);
1519         destroy_inodecache();
1520         exit_ext2_xattr();
1521 }
1522
1523 module_init(init_ext2_fs)
1524 module_exit(exit_ext2_fs)