318ebc58bb7b73dcc5230e85c22e88627daefeff
[linux-3.10.git] / fs / ext2 / super.c
1 /*
2  *  linux/fs/ext2/super.c
3  *
4  * Copyright (C) 1992, 1993, 1994, 1995
5  * Remy Card (card@masi.ibp.fr)
6  * Laboratoire MASI - Institut Blaise Pascal
7  * Universite Pierre et Marie Curie (Paris VI)
8  *
9  *  from
10  *
11  *  linux/fs/minix/inode.c
12  *
13  *  Copyright (C) 1991, 1992  Linus Torvalds
14  *
15  *  Big-endian to little-endian byte-swapping/bitmaps by
16  *        David S. Miller (davem@caip.rutgers.edu), 1995
17  */
18
19 #include <linux/module.h>
20 #include <linux/string.h>
21 #include <linux/fs.h>
22 #include <linux/slab.h>
23 #include <linux/init.h>
24 #include <linux/blkdev.h>
25 #include <linux/parser.h>
26 #include <linux/random.h>
27 #include <linux/buffer_head.h>
28 #include <linux/exportfs.h>
29 #include <linux/vfs.h>
30 #include <linux/seq_file.h>
31 #include <linux/mount.h>
32 #include <linux/log2.h>
33 #include <linux/quotaops.h>
34 #include <asm/uaccess.h>
35 #include "ext2.h"
36 #include "xattr.h"
37 #include "acl.h"
38 #include "xip.h"
39
40 static void ext2_sync_super(struct super_block *sb,
41                             struct ext2_super_block *es, int wait);
42 static int ext2_remount (struct super_block * sb, int * flags, char * data);
43 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
44 static int ext2_sync_fs(struct super_block *sb, int wait);
45
46 void ext2_error (struct super_block * sb, const char * function,
47                  const char * fmt, ...)
48 {
49         va_list args;
50         struct ext2_sb_info *sbi = EXT2_SB(sb);
51         struct ext2_super_block *es = sbi->s_es;
52
53         if (!(sb->s_flags & MS_RDONLY)) {
54                 spin_lock(&sbi->s_lock);
55                 sbi->s_mount_state |= EXT2_ERROR_FS;
56                 es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
57                 spin_unlock(&sbi->s_lock);
58                 ext2_sync_super(sb, es, 1);
59         }
60
61         va_start(args, fmt);
62         printk(KERN_CRIT "EXT2-fs (%s): error: %s: ", sb->s_id, function);
63         vprintk(fmt, args);
64         printk("\n");
65         va_end(args);
66
67         if (test_opt(sb, ERRORS_PANIC))
68                 panic("EXT2-fs: panic from previous error\n");
69         if (test_opt(sb, ERRORS_RO)) {
70                 ext2_msg(sb, KERN_CRIT,
71                              "error: remounting filesystem read-only");
72                 sb->s_flags |= MS_RDONLY;
73         }
74 }
75
76 void ext2_msg(struct super_block *sb, const char *prefix,
77                 const char *fmt, ...)
78 {
79         va_list args;
80
81         va_start(args, fmt);
82         printk("%sEXT2-fs (%s): ", prefix, sb->s_id);
83         vprintk(fmt, args);
84         printk("\n");
85         va_end(args);
86 }
87
88 /*
89  * This must be called with sbi->s_lock held.
90  */
91 void ext2_update_dynamic_rev(struct super_block *sb)
92 {
93         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
94
95         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
96                 return;
97
98         ext2_msg(sb, KERN_WARNING,
99                      "warning: updating to rev %d because of "
100                      "new feature flag, running e2fsck is recommended",
101                      EXT2_DYNAMIC_REV);
102
103         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
104         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
105         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
106         /* leave es->s_feature_*compat flags alone */
107         /* es->s_uuid will be set by e2fsck if empty */
108
109         /*
110          * The rest of the superblock fields should be zero, and if not it
111          * means they are likely already in use, so leave them alone.  We
112          * can leave it up to e2fsck to clean up any inconsistencies there.
113          */
114 }
115
116 static void ext2_put_super (struct super_block * sb)
117 {
118         int db_count;
119         int i;
120         struct ext2_sb_info *sbi = EXT2_SB(sb);
121
122         if (sb->s_dirt)
123                 ext2_write_super(sb);
124
125         ext2_xattr_put_super(sb);
126         if (!(sb->s_flags & MS_RDONLY)) {
127                 struct ext2_super_block *es = sbi->s_es;
128
129                 spin_lock(&sbi->s_lock);
130                 es->s_state = cpu_to_le16(sbi->s_mount_state);
131                 spin_unlock(&sbi->s_lock);
132                 ext2_sync_super(sb, es, 1);
133         }
134         db_count = sbi->s_gdb_count;
135         for (i = 0; i < db_count; i++)
136                 if (sbi->s_group_desc[i])
137                         brelse (sbi->s_group_desc[i]);
138         kfree(sbi->s_group_desc);
139         kfree(sbi->s_debts);
140         percpu_counter_destroy(&sbi->s_freeblocks_counter);
141         percpu_counter_destroy(&sbi->s_freeinodes_counter);
142         percpu_counter_destroy(&sbi->s_dirs_counter);
143         brelse (sbi->s_sbh);
144         sb->s_fs_info = NULL;
145         kfree(sbi->s_blockgroup_lock);
146         kfree(sbi);
147 }
148
149 static struct kmem_cache * ext2_inode_cachep;
150
151 static struct inode *ext2_alloc_inode(struct super_block *sb)
152 {
153         struct ext2_inode_info *ei;
154         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
155         if (!ei)
156                 return NULL;
157         ei->i_block_alloc_info = NULL;
158         ei->vfs_inode.i_version = 1;
159         return &ei->vfs_inode;
160 }
161
162 static void ext2_destroy_inode(struct inode *inode)
163 {
164         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
165 }
166
167 static void init_once(void *foo)
168 {
169         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
170
171         rwlock_init(&ei->i_meta_lock);
172 #ifdef CONFIG_EXT2_FS_XATTR
173         init_rwsem(&ei->xattr_sem);
174 #endif
175         mutex_init(&ei->truncate_mutex);
176         inode_init_once(&ei->vfs_inode);
177 }
178
179 static int init_inodecache(void)
180 {
181         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
182                                              sizeof(struct ext2_inode_info),
183                                              0, (SLAB_RECLAIM_ACCOUNT|
184                                                 SLAB_MEM_SPREAD),
185                                              init_once);
186         if (ext2_inode_cachep == NULL)
187                 return -ENOMEM;
188         return 0;
189 }
190
191 static void destroy_inodecache(void)
192 {
193         kmem_cache_destroy(ext2_inode_cachep);
194 }
195
196 static void ext2_clear_inode(struct inode *inode)
197 {
198         struct ext2_block_alloc_info *rsv = EXT2_I(inode)->i_block_alloc_info;
199
200         dquot_drop(inode);
201         ext2_discard_reservation(inode);
202         EXT2_I(inode)->i_block_alloc_info = NULL;
203         if (unlikely(rsv))
204                 kfree(rsv);
205 }
206
207 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
208 {
209         struct super_block *sb = vfs->mnt_sb;
210         struct ext2_sb_info *sbi = EXT2_SB(sb);
211         struct ext2_super_block *es = sbi->s_es;
212         unsigned long def_mount_opts;
213
214         spin_lock(&sbi->s_lock);
215         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
216
217         if (sbi->s_sb_block != 1)
218                 seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
219         if (test_opt(sb, MINIX_DF))
220                 seq_puts(seq, ",minixdf");
221         if (test_opt(sb, GRPID))
222                 seq_puts(seq, ",grpid");
223         if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
224                 seq_puts(seq, ",nogrpid");
225         if (sbi->s_resuid != EXT2_DEF_RESUID ||
226             le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
227                 seq_printf(seq, ",resuid=%u", sbi->s_resuid);
228         }
229         if (sbi->s_resgid != EXT2_DEF_RESGID ||
230             le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
231                 seq_printf(seq, ",resgid=%u", sbi->s_resgid);
232         }
233         if (test_opt(sb, ERRORS_RO)) {
234                 int def_errors = le16_to_cpu(es->s_errors);
235
236                 if (def_errors == EXT2_ERRORS_PANIC ||
237                     def_errors == EXT2_ERRORS_CONTINUE) {
238                         seq_puts(seq, ",errors=remount-ro");
239                 }
240         }
241         if (test_opt(sb, ERRORS_CONT))
242                 seq_puts(seq, ",errors=continue");
243         if (test_opt(sb, ERRORS_PANIC))
244                 seq_puts(seq, ",errors=panic");
245         if (test_opt(sb, NO_UID32))
246                 seq_puts(seq, ",nouid32");
247         if (test_opt(sb, DEBUG))
248                 seq_puts(seq, ",debug");
249         if (test_opt(sb, OLDALLOC))
250                 seq_puts(seq, ",oldalloc");
251
252 #ifdef CONFIG_EXT2_FS_XATTR
253         if (test_opt(sb, XATTR_USER))
254                 seq_puts(seq, ",user_xattr");
255         if (!test_opt(sb, XATTR_USER) &&
256             (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
257                 seq_puts(seq, ",nouser_xattr");
258         }
259 #endif
260
261 #ifdef CONFIG_EXT2_FS_POSIX_ACL
262         if (test_opt(sb, POSIX_ACL))
263                 seq_puts(seq, ",acl");
264         if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
265                 seq_puts(seq, ",noacl");
266 #endif
267
268         if (test_opt(sb, NOBH))
269                 seq_puts(seq, ",nobh");
270
271 #if defined(CONFIG_QUOTA)
272         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
273                 seq_puts(seq, ",usrquota");
274
275         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
276                 seq_puts(seq, ",grpquota");
277 #endif
278
279 #if defined(CONFIG_EXT2_FS_XIP)
280         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
281                 seq_puts(seq, ",xip");
282 #endif
283
284         if (!test_opt(sb, RESERVATION))
285                 seq_puts(seq, ",noreservation");
286
287         spin_unlock(&sbi->s_lock);
288         return 0;
289 }
290
291 #ifdef CONFIG_QUOTA
292 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
293 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
294 #endif
295
296 static const struct super_operations ext2_sops = {
297         .alloc_inode    = ext2_alloc_inode,
298         .destroy_inode  = ext2_destroy_inode,
299         .write_inode    = ext2_write_inode,
300         .delete_inode   = ext2_delete_inode,
301         .put_super      = ext2_put_super,
302         .write_super    = ext2_write_super,
303         .sync_fs        = ext2_sync_fs,
304         .statfs         = ext2_statfs,
305         .remount_fs     = ext2_remount,
306         .clear_inode    = ext2_clear_inode,
307         .show_options   = ext2_show_options,
308 #ifdef CONFIG_QUOTA
309         .quota_read     = ext2_quota_read,
310         .quota_write    = ext2_quota_write,
311 #endif
312 };
313
314 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
315                 u64 ino, u32 generation)
316 {
317         struct inode *inode;
318
319         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
320                 return ERR_PTR(-ESTALE);
321         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
322                 return ERR_PTR(-ESTALE);
323
324         /* iget isn't really right if the inode is currently unallocated!!
325          * ext2_read_inode currently does appropriate checks, but
326          * it might be "neater" to call ext2_get_inode first and check
327          * if the inode is valid.....
328          */
329         inode = ext2_iget(sb, ino);
330         if (IS_ERR(inode))
331                 return ERR_CAST(inode);
332         if (generation && inode->i_generation != generation) {
333                 /* we didn't find the right inode.. */
334                 iput(inode);
335                 return ERR_PTR(-ESTALE);
336         }
337         return inode;
338 }
339
340 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
341                 int fh_len, int fh_type)
342 {
343         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
344                                     ext2_nfs_get_inode);
345 }
346
347 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
348                 int fh_len, int fh_type)
349 {
350         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
351                                     ext2_nfs_get_inode);
352 }
353
354 /* Yes, most of these are left as NULL!!
355  * A NULL value implies the default, which works with ext2-like file
356  * systems, but can be improved upon.
357  * Currently only get_parent is required.
358  */
359 static const struct export_operations ext2_export_ops = {
360         .fh_to_dentry = ext2_fh_to_dentry,
361         .fh_to_parent = ext2_fh_to_parent,
362         .get_parent = ext2_get_parent,
363 };
364
365 static unsigned long get_sb_block(void **data)
366 {
367         unsigned long   sb_block;
368         char            *options = (char *) *data;
369
370         if (!options || strncmp(options, "sb=", 3) != 0)
371                 return 1;       /* Default location */
372         options += 3;
373         sb_block = simple_strtoul(options, &options, 0);
374         if (*options && *options != ',') {
375                 printk("EXT2-fs: Invalid sb specification: %s\n",
376                        (char *) *data);
377                 return 1;
378         }
379         if (*options == ',')
380                 options++;
381         *data = (void *) options;
382         return sb_block;
383 }
384
385 enum {
386         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
387         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
388         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
389         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
390         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
391         Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
392 };
393
394 static const match_table_t tokens = {
395         {Opt_bsd_df, "bsddf"},
396         {Opt_minix_df, "minixdf"},
397         {Opt_grpid, "grpid"},
398         {Opt_grpid, "bsdgroups"},
399         {Opt_nogrpid, "nogrpid"},
400         {Opt_nogrpid, "sysvgroups"},
401         {Opt_resgid, "resgid=%u"},
402         {Opt_resuid, "resuid=%u"},
403         {Opt_sb, "sb=%u"},
404         {Opt_err_cont, "errors=continue"},
405         {Opt_err_panic, "errors=panic"},
406         {Opt_err_ro, "errors=remount-ro"},
407         {Opt_nouid32, "nouid32"},
408         {Opt_nocheck, "check=none"},
409         {Opt_nocheck, "nocheck"},
410         {Opt_debug, "debug"},
411         {Opt_oldalloc, "oldalloc"},
412         {Opt_orlov, "orlov"},
413         {Opt_nobh, "nobh"},
414         {Opt_user_xattr, "user_xattr"},
415         {Opt_nouser_xattr, "nouser_xattr"},
416         {Opt_acl, "acl"},
417         {Opt_noacl, "noacl"},
418         {Opt_xip, "xip"},
419         {Opt_grpquota, "grpquota"},
420         {Opt_ignore, "noquota"},
421         {Opt_quota, "quota"},
422         {Opt_usrquota, "usrquota"},
423         {Opt_reservation, "reservation"},
424         {Opt_noreservation, "noreservation"},
425         {Opt_err, NULL}
426 };
427
428 static int parse_options(char *options, struct super_block *sb)
429 {
430         char *p;
431         struct ext2_sb_info *sbi = EXT2_SB(sb);
432         substring_t args[MAX_OPT_ARGS];
433         int option;
434
435         if (!options)
436                 return 1;
437
438         while ((p = strsep (&options, ",")) != NULL) {
439                 int token;
440                 if (!*p)
441                         continue;
442
443                 token = match_token(p, tokens, args);
444                 switch (token) {
445                 case Opt_bsd_df:
446                         clear_opt (sbi->s_mount_opt, MINIX_DF);
447                         break;
448                 case Opt_minix_df:
449                         set_opt (sbi->s_mount_opt, MINIX_DF);
450                         break;
451                 case Opt_grpid:
452                         set_opt (sbi->s_mount_opt, GRPID);
453                         break;
454                 case Opt_nogrpid:
455                         clear_opt (sbi->s_mount_opt, GRPID);
456                         break;
457                 case Opt_resuid:
458                         if (match_int(&args[0], &option))
459                                 return 0;
460                         sbi->s_resuid = option;
461                         break;
462                 case Opt_resgid:
463                         if (match_int(&args[0], &option))
464                                 return 0;
465                         sbi->s_resgid = option;
466                         break;
467                 case Opt_sb:
468                         /* handled by get_sb_block() instead of here */
469                         /* *sb_block = match_int(&args[0]); */
470                         break;
471                 case Opt_err_panic:
472                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
473                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
474                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
475                         break;
476                 case Opt_err_ro:
477                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
478                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
479                         set_opt (sbi->s_mount_opt, ERRORS_RO);
480                         break;
481                 case Opt_err_cont:
482                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
483                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
484                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
485                         break;
486                 case Opt_nouid32:
487                         set_opt (sbi->s_mount_opt, NO_UID32);
488                         break;
489                 case Opt_nocheck:
490                         clear_opt (sbi->s_mount_opt, CHECK);
491                         break;
492                 case Opt_debug:
493                         set_opt (sbi->s_mount_opt, DEBUG);
494                         break;
495                 case Opt_oldalloc:
496                         set_opt (sbi->s_mount_opt, OLDALLOC);
497                         break;
498                 case Opt_orlov:
499                         clear_opt (sbi->s_mount_opt, OLDALLOC);
500                         break;
501                 case Opt_nobh:
502                         set_opt (sbi->s_mount_opt, NOBH);
503                         break;
504 #ifdef CONFIG_EXT2_FS_XATTR
505                 case Opt_user_xattr:
506                         set_opt (sbi->s_mount_opt, XATTR_USER);
507                         break;
508                 case Opt_nouser_xattr:
509                         clear_opt (sbi->s_mount_opt, XATTR_USER);
510                         break;
511 #else
512                 case Opt_user_xattr:
513                 case Opt_nouser_xattr:
514                         ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
515                                 "not supported");
516                         break;
517 #endif
518 #ifdef CONFIG_EXT2_FS_POSIX_ACL
519                 case Opt_acl:
520                         set_opt(sbi->s_mount_opt, POSIX_ACL);
521                         break;
522                 case Opt_noacl:
523                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
524                         break;
525 #else
526                 case Opt_acl:
527                 case Opt_noacl:
528                         ext2_msg(sb, KERN_INFO,
529                                 "(no)acl options not supported");
530                         break;
531 #endif
532                 case Opt_xip:
533 #ifdef CONFIG_EXT2_FS_XIP
534                         set_opt (sbi->s_mount_opt, XIP);
535 #else
536                         ext2_msg(sb, KERN_INFO, "xip option not supported");
537 #endif
538                         break;
539
540 #if defined(CONFIG_QUOTA)
541                 case Opt_quota:
542                 case Opt_usrquota:
543                         set_opt(sbi->s_mount_opt, USRQUOTA);
544                         break;
545
546                 case Opt_grpquota:
547                         set_opt(sbi->s_mount_opt, GRPQUOTA);
548                         break;
549 #else
550                 case Opt_quota:
551                 case Opt_usrquota:
552                 case Opt_grpquota:
553                         ext2_msg(sb, KERN_INFO,
554                                 "quota operations not supported");
555                         break;
556 #endif
557
558                 case Opt_reservation:
559                         set_opt(sbi->s_mount_opt, RESERVATION);
560                         ext2_msg(sb, KERN_INFO, "reservations ON");
561                         break;
562                 case Opt_noreservation:
563                         clear_opt(sbi->s_mount_opt, RESERVATION);
564                         ext2_msg(sb, KERN_INFO, "reservations OFF");
565                         break;
566                 case Opt_ignore:
567                         break;
568                 default:
569                         return 0;
570                 }
571         }
572         return 1;
573 }
574
575 static int ext2_setup_super (struct super_block * sb,
576                               struct ext2_super_block * es,
577                               int read_only)
578 {
579         int res = 0;
580         struct ext2_sb_info *sbi = EXT2_SB(sb);
581
582         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
583                 ext2_msg(sb, KERN_ERR,
584                         "error: revision level too high, "
585                         "forcing read-only mode");
586                 res = MS_RDONLY;
587         }
588         if (read_only)
589                 return res;
590         if (!(sbi->s_mount_state & EXT2_VALID_FS))
591                 ext2_msg(sb, KERN_WARNING,
592                         "warning: mounting unchecked fs, "
593                         "running e2fsck is recommended");
594         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
595                 ext2_msg(sb, KERN_WARNING,
596                         "warning: mounting fs with errors, "
597                         "running e2fsck is recommended");
598         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
599                  le16_to_cpu(es->s_mnt_count) >=
600                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
601                 ext2_msg(sb, KERN_WARNING,
602                         "warning: maximal mount count reached, "
603                         "running e2fsck is recommended");
604         else if (le32_to_cpu(es->s_checkinterval) &&
605                 (le32_to_cpu(es->s_lastcheck) +
606                         le32_to_cpu(es->s_checkinterval) <= get_seconds()))
607                 ext2_msg(sb, KERN_WARNING,
608                         "warning: checktime reached, "
609                         "running e2fsck is recommended");
610         if (!le16_to_cpu(es->s_max_mnt_count))
611                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
612         le16_add_cpu(&es->s_mnt_count, 1);
613         if (test_opt (sb, DEBUG))
614                 ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
615                         "bpg=%lu, ipg=%lu, mo=%04lx]",
616                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
617                         sbi->s_frag_size,
618                         sbi->s_groups_count,
619                         EXT2_BLOCKS_PER_GROUP(sb),
620                         EXT2_INODES_PER_GROUP(sb),
621                         sbi->s_mount_opt);
622         return res;
623 }
624
625 static int ext2_check_descriptors(struct super_block *sb)
626 {
627         int i;
628         struct ext2_sb_info *sbi = EXT2_SB(sb);
629
630         ext2_debug ("Checking group descriptors");
631
632         for (i = 0; i < sbi->s_groups_count; i++) {
633                 struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
634                 ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
635                 ext2_fsblk_t last_block;
636
637                 if (i == sbi->s_groups_count - 1)
638                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
639                 else
640                         last_block = first_block +
641                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
642
643                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
644                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
645                 {
646                         ext2_error (sb, "ext2_check_descriptors",
647                                     "Block bitmap for group %d"
648                                     " not in group (block %lu)!",
649                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
650                         return 0;
651                 }
652                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
653                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
654                 {
655                         ext2_error (sb, "ext2_check_descriptors",
656                                     "Inode bitmap for group %d"
657                                     " not in group (block %lu)!",
658                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
659                         return 0;
660                 }
661                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
662                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
663                     last_block)
664                 {
665                         ext2_error (sb, "ext2_check_descriptors",
666                                     "Inode table for group %d"
667                                     " not in group (block %lu)!",
668                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
669                         return 0;
670                 }
671         }
672         return 1;
673 }
674
675 /*
676  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
677  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
678  * We need to be 1 filesystem block less than the 2^32 sector limit.
679  */
680 static loff_t ext2_max_size(int bits)
681 {
682         loff_t res = EXT2_NDIR_BLOCKS;
683         int meta_blocks;
684         loff_t upper_limit;
685
686         /* This is calculated to be the largest file size for a
687          * dense, file such that the total number of
688          * sectors in the file, including data and all indirect blocks,
689          * does not exceed 2^32 -1
690          * __u32 i_blocks representing the total number of
691          * 512 bytes blocks of the file
692          */
693         upper_limit = (1LL << 32) - 1;
694
695         /* total blocks in file system block size */
696         upper_limit >>= (bits - 9);
697
698
699         /* indirect blocks */
700         meta_blocks = 1;
701         /* double indirect blocks */
702         meta_blocks += 1 + (1LL << (bits-2));
703         /* tripple indirect blocks */
704         meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
705
706         upper_limit -= meta_blocks;
707         upper_limit <<= bits;
708
709         res += 1LL << (bits-2);
710         res += 1LL << (2*(bits-2));
711         res += 1LL << (3*(bits-2));
712         res <<= bits;
713         if (res > upper_limit)
714                 res = upper_limit;
715
716         if (res > MAX_LFS_FILESIZE)
717                 res = MAX_LFS_FILESIZE;
718
719         return res;
720 }
721
722 static unsigned long descriptor_loc(struct super_block *sb,
723                                     unsigned long logic_sb_block,
724                                     int nr)
725 {
726         struct ext2_sb_info *sbi = EXT2_SB(sb);
727         unsigned long bg, first_meta_bg;
728         int has_super = 0;
729         
730         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
731
732         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
733             nr < first_meta_bg)
734                 return (logic_sb_block + nr + 1);
735         bg = sbi->s_desc_per_block * nr;
736         if (ext2_bg_has_super(sb, bg))
737                 has_super = 1;
738
739         return ext2_group_first_block_no(sb, bg) + has_super;
740 }
741
742 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
743 {
744         struct buffer_head * bh;
745         struct ext2_sb_info * sbi;
746         struct ext2_super_block * es;
747         struct inode *root;
748         unsigned long block;
749         unsigned long sb_block = get_sb_block(&data);
750         unsigned long logic_sb_block;
751         unsigned long offset = 0;
752         unsigned long def_mount_opts;
753         long ret = -EINVAL;
754         int blocksize = BLOCK_SIZE;
755         int db_count;
756         int i, j;
757         __le32 features;
758         int err;
759
760         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
761         if (!sbi)
762                 return -ENOMEM;
763
764         sbi->s_blockgroup_lock =
765                 kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
766         if (!sbi->s_blockgroup_lock) {
767                 kfree(sbi);
768                 return -ENOMEM;
769         }
770         sb->s_fs_info = sbi;
771         sbi->s_sb_block = sb_block;
772
773         spin_lock_init(&sbi->s_lock);
774
775         /*
776          * See what the current blocksize for the device is, and
777          * use that as the blocksize.  Otherwise (or if the blocksize
778          * is smaller than the default) use the default.
779          * This is important for devices that have a hardware
780          * sectorsize that is larger than the default.
781          */
782         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
783         if (!blocksize) {
784                 ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
785                 goto failed_sbi;
786         }
787
788         /*
789          * If the superblock doesn't start on a hardware sector boundary,
790          * calculate the offset.  
791          */
792         if (blocksize != BLOCK_SIZE) {
793                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
794                 offset = (sb_block*BLOCK_SIZE) % blocksize;
795         } else {
796                 logic_sb_block = sb_block;
797         }
798
799         if (!(bh = sb_bread(sb, logic_sb_block))) {
800                 ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
801                 goto failed_sbi;
802         }
803         /*
804          * Note: s_es must be initialized as soon as possible because
805          *       some ext2 macro-instructions depend on its value
806          */
807         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
808         sbi->s_es = es;
809         sb->s_magic = le16_to_cpu(es->s_magic);
810
811         if (sb->s_magic != EXT2_SUPER_MAGIC)
812                 goto cantfind_ext2;
813
814         /* Set defaults before we parse the mount options */
815         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
816         if (def_mount_opts & EXT2_DEFM_DEBUG)
817                 set_opt(sbi->s_mount_opt, DEBUG);
818         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
819                 set_opt(sbi->s_mount_opt, GRPID);
820         if (def_mount_opts & EXT2_DEFM_UID16)
821                 set_opt(sbi->s_mount_opt, NO_UID32);
822 #ifdef CONFIG_EXT2_FS_XATTR
823         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
824                 set_opt(sbi->s_mount_opt, XATTR_USER);
825 #endif
826 #ifdef CONFIG_EXT2_FS_POSIX_ACL
827         if (def_mount_opts & EXT2_DEFM_ACL)
828                 set_opt(sbi->s_mount_opt, POSIX_ACL);
829 #endif
830         
831         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
832                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
833         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
834                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
835         else
836                 set_opt(sbi->s_mount_opt, ERRORS_RO);
837
838         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
839         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
840         
841         set_opt(sbi->s_mount_opt, RESERVATION);
842
843         if (!parse_options((char *) data, sb))
844                 goto failed_mount;
845
846         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
847                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
848                  MS_POSIXACL : 0);
849
850         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
851                                     EXT2_MOUNT_XIP if not */
852
853         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
854             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
855              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
856              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
857                 ext2_msg(sb, KERN_WARNING,
858                         "warning: feature flags set on rev 0 fs, "
859                         "running e2fsck is recommended");
860         /*
861          * Check feature flags regardless of the revision level, since we
862          * previously didn't change the revision level when setting the flags,
863          * so there is a chance incompat flags are set on a rev 0 filesystem.
864          */
865         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
866         if (features) {
867                 ext2_msg(sb, KERN_ERR,  "error: couldn't mount because of "
868                        "unsupported optional features (%x)",
869                         le32_to_cpu(features));
870                 goto failed_mount;
871         }
872         if (!(sb->s_flags & MS_RDONLY) &&
873             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
874                 ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
875                        "unsupported optional features (%x)",
876                        le32_to_cpu(features));
877                 goto failed_mount;
878         }
879
880         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
881
882         if (ext2_use_xip(sb) && blocksize != PAGE_SIZE) {
883                 if (!silent)
884                         ext2_msg(sb, KERN_ERR,
885                                 "error: unsupported blocksize for xip");
886                 goto failed_mount;
887         }
888
889         /* If the blocksize doesn't match, re-read the thing.. */
890         if (sb->s_blocksize != blocksize) {
891                 brelse(bh);
892
893                 if (!sb_set_blocksize(sb, blocksize)) {
894                         ext2_msg(sb, KERN_ERR, "error: blocksize is too small");
895                         goto failed_sbi;
896                 }
897
898                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
899                 offset = (sb_block*BLOCK_SIZE) % blocksize;
900                 bh = sb_bread(sb, logic_sb_block);
901                 if(!bh) {
902                         ext2_msg(sb, KERN_ERR, "error: couldn't read"
903                                 "superblock on 2nd try");
904                         goto failed_sbi;
905                 }
906                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
907                 sbi->s_es = es;
908                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
909                         ext2_msg(sb, KERN_ERR, "error: magic mismatch");
910                         goto failed_mount;
911                 }
912         }
913
914         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
915
916         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
917                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
918                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
919         } else {
920                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
921                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
922                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
923                     !is_power_of_2(sbi->s_inode_size) ||
924                     (sbi->s_inode_size > blocksize)) {
925                         ext2_msg(sb, KERN_ERR,
926                                 "error: unsupported inode size: %d",
927                                 sbi->s_inode_size);
928                         goto failed_mount;
929                 }
930         }
931
932         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
933                                    le32_to_cpu(es->s_log_frag_size);
934         if (sbi->s_frag_size == 0)
935                 goto cantfind_ext2;
936         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
937
938         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
939         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
940         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
941
942         if (EXT2_INODE_SIZE(sb) == 0)
943                 goto cantfind_ext2;
944         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
945         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
946                 goto cantfind_ext2;
947         sbi->s_itb_per_group = sbi->s_inodes_per_group /
948                                         sbi->s_inodes_per_block;
949         sbi->s_desc_per_block = sb->s_blocksize /
950                                         sizeof (struct ext2_group_desc);
951         sbi->s_sbh = bh;
952         sbi->s_mount_state = le16_to_cpu(es->s_state);
953         sbi->s_addr_per_block_bits =
954                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
955         sbi->s_desc_per_block_bits =
956                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
957
958         if (sb->s_magic != EXT2_SUPER_MAGIC)
959                 goto cantfind_ext2;
960
961         if (sb->s_blocksize != bh->b_size) {
962                 if (!silent)
963                         ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
964                 goto failed_mount;
965         }
966
967         if (sb->s_blocksize != sbi->s_frag_size) {
968                 ext2_msg(sb, KERN_ERR,
969                         "error: fragsize %lu != blocksize %lu"
970                         "(not supported yet)",
971                         sbi->s_frag_size, sb->s_blocksize);
972                 goto failed_mount;
973         }
974
975         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
976                 ext2_msg(sb, KERN_ERR,
977                         "error: #blocks per group too big: %lu",
978                         sbi->s_blocks_per_group);
979                 goto failed_mount;
980         }
981         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
982                 ext2_msg(sb, KERN_ERR,
983                         "error: #fragments per group too big: %lu",
984                         sbi->s_frags_per_group);
985                 goto failed_mount;
986         }
987         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
988                 ext2_msg(sb, KERN_ERR,
989                         "error: #inodes per group too big: %lu",
990                         sbi->s_inodes_per_group);
991                 goto failed_mount;
992         }
993
994         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
995                 goto cantfind_ext2;
996         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
997                                 le32_to_cpu(es->s_first_data_block) - 1)
998                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
999         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
1000                    EXT2_DESC_PER_BLOCK(sb);
1001         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
1002         if (sbi->s_group_desc == NULL) {
1003                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
1004                 goto failed_mount;
1005         }
1006         bgl_lock_init(sbi->s_blockgroup_lock);
1007         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1008         if (!sbi->s_debts) {
1009                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
1010                 goto failed_mount_group_desc;
1011         }
1012         for (i = 0; i < db_count; i++) {
1013                 block = descriptor_loc(sb, logic_sb_block, i);
1014                 sbi->s_group_desc[i] = sb_bread(sb, block);
1015                 if (!sbi->s_group_desc[i]) {
1016                         for (j = 0; j < i; j++)
1017                                 brelse (sbi->s_group_desc[j]);
1018                         ext2_msg(sb, KERN_ERR,
1019                                 "error: unable to read group descriptors");
1020                         goto failed_mount_group_desc;
1021                 }
1022         }
1023         if (!ext2_check_descriptors (sb)) {
1024                 ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1025                 goto failed_mount2;
1026         }
1027         sbi->s_gdb_count = db_count;
1028         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1029         spin_lock_init(&sbi->s_next_gen_lock);
1030
1031         /* per fileystem reservation list head & lock */
1032         spin_lock_init(&sbi->s_rsv_window_lock);
1033         sbi->s_rsv_window_root = RB_ROOT;
1034         /*
1035          * Add a single, static dummy reservation to the start of the
1036          * reservation window list --- it gives us a placeholder for
1037          * append-at-start-of-list which makes the allocation logic
1038          * _much_ simpler.
1039          */
1040         sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1041         sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1042         sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1043         sbi->s_rsv_window_head.rsv_goal_size = 0;
1044         ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1045
1046         err = percpu_counter_init(&sbi->s_freeblocks_counter,
1047                                 ext2_count_free_blocks(sb));
1048         if (!err) {
1049                 err = percpu_counter_init(&sbi->s_freeinodes_counter,
1050                                 ext2_count_free_inodes(sb));
1051         }
1052         if (!err) {
1053                 err = percpu_counter_init(&sbi->s_dirs_counter,
1054                                 ext2_count_dirs(sb));
1055         }
1056         if (err) {
1057                 ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1058                 goto failed_mount3;
1059         }
1060         /*
1061          * set up enough so that it can read an inode
1062          */
1063         sb->s_op = &ext2_sops;
1064         sb->s_export_op = &ext2_export_ops;
1065         sb->s_xattr = ext2_xattr_handlers;
1066         root = ext2_iget(sb, EXT2_ROOT_INO);
1067         if (IS_ERR(root)) {
1068                 ret = PTR_ERR(root);
1069                 goto failed_mount3;
1070         }
1071         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1072                 iput(root);
1073                 ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1074                 goto failed_mount3;
1075         }
1076
1077         sb->s_root = d_alloc_root(root);
1078         if (!sb->s_root) {
1079                 iput(root);
1080                 ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1081                 ret = -ENOMEM;
1082                 goto failed_mount3;
1083         }
1084         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1085                 ext2_msg(sb, KERN_WARNING,
1086                         "warning: mounting ext3 filesystem as ext2");
1087         if (ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY))
1088                 sb->s_flags |= MS_RDONLY;
1089         ext2_write_super(sb);
1090         return 0;
1091
1092 cantfind_ext2:
1093         if (!silent)
1094                 ext2_msg(sb, KERN_ERR,
1095                         "error: can't find an ext2 filesystem on dev %s.",
1096                         sb->s_id);
1097         goto failed_mount;
1098 failed_mount3:
1099         percpu_counter_destroy(&sbi->s_freeblocks_counter);
1100         percpu_counter_destroy(&sbi->s_freeinodes_counter);
1101         percpu_counter_destroy(&sbi->s_dirs_counter);
1102 failed_mount2:
1103         for (i = 0; i < db_count; i++)
1104                 brelse(sbi->s_group_desc[i]);
1105 failed_mount_group_desc:
1106         kfree(sbi->s_group_desc);
1107         kfree(sbi->s_debts);
1108 failed_mount:
1109         brelse(bh);
1110 failed_sbi:
1111         sb->s_fs_info = NULL;
1112         kfree(sbi->s_blockgroup_lock);
1113         kfree(sbi);
1114         return ret;
1115 }
1116
1117 static void ext2_clear_super_error(struct super_block *sb)
1118 {
1119         struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1120
1121         if (buffer_write_io_error(sbh)) {
1122                 /*
1123                  * Oh, dear.  A previous attempt to write the
1124                  * superblock failed.  This could happen because the
1125                  * USB device was yanked out.  Or it could happen to
1126                  * be a transient write error and maybe the block will
1127                  * be remapped.  Nothing we can do but to retry the
1128                  * write and hope for the best.
1129                  */
1130                 ext2_msg(sb, KERN_ERR,
1131                        "previous I/O error to superblock detected\n");
1132                 clear_buffer_write_io_error(sbh);
1133                 set_buffer_uptodate(sbh);
1134         }
1135 }
1136
1137 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
1138                             int wait)
1139 {
1140         ext2_clear_super_error(sb);
1141         spin_lock(&EXT2_SB(sb)->s_lock);
1142         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1143         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1144         es->s_wtime = cpu_to_le32(get_seconds());
1145         /* unlock before we do IO */
1146         spin_unlock(&EXT2_SB(sb)->s_lock);
1147         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1148         if (wait)
1149                 sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1150         sb->s_dirt = 0;
1151 }
1152
1153 /*
1154  * In the second extended file system, it is not necessary to
1155  * write the super block since we use a mapping of the
1156  * disk super block in a buffer.
1157  *
1158  * However, this function is still used to set the fs valid
1159  * flags to 0.  We need to set this flag to 0 since the fs
1160  * may have been checked while mounted and e2fsck may have
1161  * set s_state to EXT2_VALID_FS after some corrections.
1162  */
1163 static int ext2_sync_fs(struct super_block *sb, int wait)
1164 {
1165         struct ext2_sb_info *sbi = EXT2_SB(sb);
1166         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1167
1168         spin_lock(&sbi->s_lock);
1169         if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1170                 ext2_debug("setting valid to 0\n");
1171                 es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1172         }
1173         spin_unlock(&sbi->s_lock);
1174         ext2_sync_super(sb, es, wait);
1175         return 0;
1176 }
1177
1178
1179 void ext2_write_super(struct super_block *sb)
1180 {
1181         if (!(sb->s_flags & MS_RDONLY))
1182                 ext2_sync_fs(sb, 1);
1183         else
1184                 sb->s_dirt = 0;
1185 }
1186
1187 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1188 {
1189         struct ext2_sb_info * sbi = EXT2_SB(sb);
1190         struct ext2_super_block * es;
1191         unsigned long old_mount_opt = sbi->s_mount_opt;
1192         struct ext2_mount_options old_opts;
1193         unsigned long old_sb_flags;
1194         int err;
1195
1196         spin_lock(&sbi->s_lock);
1197
1198         /* Store the old options */
1199         old_sb_flags = sb->s_flags;
1200         old_opts.s_mount_opt = sbi->s_mount_opt;
1201         old_opts.s_resuid = sbi->s_resuid;
1202         old_opts.s_resgid = sbi->s_resgid;
1203
1204         /*
1205          * Allow the "check" option to be passed as a remount option.
1206          */
1207         if (!parse_options(data, sb)) {
1208                 err = -EINVAL;
1209                 goto restore_opts;
1210         }
1211
1212         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1213                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1214
1215         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1216                                     EXT2_MOUNT_XIP if not */
1217
1218         if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1219                 ext2_msg(sb, KERN_WARNING,
1220                         "warning: unsupported blocksize for xip");
1221                 err = -EINVAL;
1222                 goto restore_opts;
1223         }
1224
1225         es = sbi->s_es;
1226         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1227             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1228             invalidate_inodes(sb)) {
1229                 ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1230                          "xip flag with busy inodes while remounting");
1231                 sbi->s_mount_opt &= ~EXT2_MOUNT_XIP;
1232                 sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;
1233         }
1234         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
1235                 spin_unlock(&sbi->s_lock);
1236                 return 0;
1237         }
1238         if (*flags & MS_RDONLY) {
1239                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1240                     !(sbi->s_mount_state & EXT2_VALID_FS)) {
1241                         spin_unlock(&sbi->s_lock);
1242                         return 0;
1243                 }
1244
1245                 /*
1246                  * OK, we are remounting a valid rw partition rdonly, so set
1247                  * the rdonly flag and then mark the partition as valid again.
1248                  */
1249                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1250                 es->s_mtime = cpu_to_le32(get_seconds());
1251                 spin_unlock(&sbi->s_lock);
1252
1253                 err = dquot_suspend(sb, -1);
1254                 if (err < 0) {
1255                         spin_lock(&sbi->s_lock);
1256                         goto restore_opts;
1257                 }
1258
1259                 ext2_sync_super(sb, es, 1);
1260         } else {
1261                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1262                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1263                 if (ret) {
1264                         ext2_msg(sb, KERN_WARNING,
1265                                 "warning: couldn't remount RDWR because of "
1266                                 "unsupported optional features (%x).",
1267                                 le32_to_cpu(ret));
1268                         err = -EROFS;
1269                         goto restore_opts;
1270                 }
1271                 /*
1272                  * Mounting a RDONLY partition read-write, so reread and
1273                  * store the current valid flag.  (It may have been changed
1274                  * by e2fsck since we originally mounted the partition.)
1275                  */
1276                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1277                 if (!ext2_setup_super (sb, es, 0))
1278                         sb->s_flags &= ~MS_RDONLY;
1279                 spin_unlock(&sbi->s_lock);
1280
1281                 ext2_write_super(sb);
1282
1283                 dquot_resume(sb, -1);
1284         }
1285
1286         return 0;
1287 restore_opts:
1288         sbi->s_mount_opt = old_opts.s_mount_opt;
1289         sbi->s_resuid = old_opts.s_resuid;
1290         sbi->s_resgid = old_opts.s_resgid;
1291         sb->s_flags = old_sb_flags;
1292         spin_unlock(&sbi->s_lock);
1293         return err;
1294 }
1295
1296 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1297 {
1298         struct super_block *sb = dentry->d_sb;
1299         struct ext2_sb_info *sbi = EXT2_SB(sb);
1300         struct ext2_super_block *es = sbi->s_es;
1301         u64 fsid;
1302
1303         spin_lock(&sbi->s_lock);
1304
1305         if (test_opt (sb, MINIX_DF))
1306                 sbi->s_overhead_last = 0;
1307         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1308                 unsigned long i, overhead = 0;
1309                 smp_rmb();
1310
1311                 /*
1312                  * Compute the overhead (FS structures). This is constant
1313                  * for a given filesystem unless the number of block groups
1314                  * changes so we cache the previous value until it does.
1315                  */
1316
1317                 /*
1318                  * All of the blocks before first_data_block are
1319                  * overhead
1320                  */
1321                 overhead = le32_to_cpu(es->s_first_data_block);
1322
1323                 /*
1324                  * Add the overhead attributed to the superblock and
1325                  * block group descriptors.  If the sparse superblocks
1326                  * feature is turned on, then not all groups have this.
1327                  */
1328                 for (i = 0; i < sbi->s_groups_count; i++)
1329                         overhead += ext2_bg_has_super(sb, i) +
1330                                 ext2_bg_num_gdb(sb, i);
1331
1332                 /*
1333                  * Every block group has an inode bitmap, a block
1334                  * bitmap, and an inode table.
1335                  */
1336                 overhead += (sbi->s_groups_count *
1337                              (2 + sbi->s_itb_per_group));
1338                 sbi->s_overhead_last = overhead;
1339                 smp_wmb();
1340                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1341         }
1342
1343         buf->f_type = EXT2_SUPER_MAGIC;
1344         buf->f_bsize = sb->s_blocksize;
1345         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1346         buf->f_bfree = ext2_count_free_blocks(sb);
1347         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1348         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1349         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1350                 buf->f_bavail = 0;
1351         buf->f_files = le32_to_cpu(es->s_inodes_count);
1352         buf->f_ffree = ext2_count_free_inodes(sb);
1353         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1354         buf->f_namelen = EXT2_NAME_LEN;
1355         fsid = le64_to_cpup((void *)es->s_uuid) ^
1356                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1357         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1358         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1359         spin_unlock(&sbi->s_lock);
1360         return 0;
1361 }
1362
1363 static int ext2_get_sb(struct file_system_type *fs_type,
1364         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1365 {
1366         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1367 }
1368
1369 #ifdef CONFIG_QUOTA
1370
1371 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1372  * acquiring the locks... As quota files are never truncated and quota code
1373  * itself serializes the operations (and noone else should touch the files)
1374  * we don't have to be afraid of races */
1375 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1376                                size_t len, loff_t off)
1377 {
1378         struct inode *inode = sb_dqopt(sb)->files[type];
1379         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1380         int err = 0;
1381         int offset = off & (sb->s_blocksize - 1);
1382         int tocopy;
1383         size_t toread;
1384         struct buffer_head tmp_bh;
1385         struct buffer_head *bh;
1386         loff_t i_size = i_size_read(inode);
1387
1388         if (off > i_size)
1389                 return 0;
1390         if (off+len > i_size)
1391                 len = i_size-off;
1392         toread = len;
1393         while (toread > 0) {
1394                 tocopy = sb->s_blocksize - offset < toread ?
1395                                 sb->s_blocksize - offset : toread;
1396
1397                 tmp_bh.b_state = 0;
1398                 tmp_bh.b_size = sb->s_blocksize;
1399                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1400                 if (err < 0)
1401                         return err;
1402                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1403                         memset(data, 0, tocopy);
1404                 else {
1405                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1406                         if (!bh)
1407                                 return -EIO;
1408                         memcpy(data, bh->b_data+offset, tocopy);
1409                         brelse(bh);
1410                 }
1411                 offset = 0;
1412                 toread -= tocopy;
1413                 data += tocopy;
1414                 blk++;
1415         }
1416         return len;
1417 }
1418
1419 /* Write to quotafile */
1420 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1421                                 const char *data, size_t len, loff_t off)
1422 {
1423         struct inode *inode = sb_dqopt(sb)->files[type];
1424         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1425         int err = 0;
1426         int offset = off & (sb->s_blocksize - 1);
1427         int tocopy;
1428         size_t towrite = len;
1429         struct buffer_head tmp_bh;
1430         struct buffer_head *bh;
1431
1432         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1433         while (towrite > 0) {
1434                 tocopy = sb->s_blocksize - offset < towrite ?
1435                                 sb->s_blocksize - offset : towrite;
1436
1437                 tmp_bh.b_state = 0;
1438                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1439                 if (err < 0)
1440                         goto out;
1441                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1442                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1443                 else
1444                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1445                 if (!bh) {
1446                         err = -EIO;
1447                         goto out;
1448                 }
1449                 lock_buffer(bh);
1450                 memcpy(bh->b_data+offset, data, tocopy);
1451                 flush_dcache_page(bh->b_page);
1452                 set_buffer_uptodate(bh);
1453                 mark_buffer_dirty(bh);
1454                 unlock_buffer(bh);
1455                 brelse(bh);
1456                 offset = 0;
1457                 towrite -= tocopy;
1458                 data += tocopy;
1459                 blk++;
1460         }
1461 out:
1462         if (len == towrite) {
1463                 mutex_unlock(&inode->i_mutex);
1464                 return err;
1465         }
1466         if (inode->i_size < off+len-towrite)
1467                 i_size_write(inode, off+len-towrite);
1468         inode->i_version++;
1469         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1470         mark_inode_dirty(inode);
1471         mutex_unlock(&inode->i_mutex);
1472         return len - towrite;
1473 }
1474
1475 #endif
1476
1477 static struct file_system_type ext2_fs_type = {
1478         .owner          = THIS_MODULE,
1479         .name           = "ext2",
1480         .get_sb         = ext2_get_sb,
1481         .kill_sb        = kill_block_super,
1482         .fs_flags       = FS_REQUIRES_DEV,
1483 };
1484
1485 static int __init init_ext2_fs(void)
1486 {
1487         int err = init_ext2_xattr();
1488         if (err)
1489                 return err;
1490         err = init_inodecache();
1491         if (err)
1492                 goto out1;
1493         err = register_filesystem(&ext2_fs_type);
1494         if (err)
1495                 goto out;
1496         return 0;
1497 out:
1498         destroy_inodecache();
1499 out1:
1500         exit_ext2_xattr();
1501         return err;
1502 }
1503
1504 static void __exit exit_ext2_fs(void)
1505 {
1506         unregister_filesystem(&ext2_fs_type);
1507         destroy_inodecache();
1508         exit_ext2_xattr();
1509 }
1510
1511 module_init(init_ext2_fs)
1512 module_exit(exit_ext2_fs)