458999638c3dee387cd4a5b091a73010ff1d8150
[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/smp_lock.h>
30 #include <linux/vfs.h>
31 #include <linux/seq_file.h>
32 #include <linux/mount.h>
33 #include <linux/log2.h>
34 #include <linux/quotaops.h>
35 #include <asm/uaccess.h>
36 #include "ext2.h"
37 #include "xattr.h"
38 #include "acl.h"
39 #include "xip.h"
40
41 static void ext2_sync_super(struct super_block *sb,
42                             struct ext2_super_block *es);
43 static int ext2_remount (struct super_block * sb, int * flags, char * data);
44 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
45 static int ext2_sync_fs(struct super_block *sb, int wait);
46
47 void ext2_error (struct super_block * sb, const char * function,
48                  const char * fmt, ...)
49 {
50         va_list args;
51         struct ext2_sb_info *sbi = EXT2_SB(sb);
52         struct ext2_super_block *es = sbi->s_es;
53
54         if (!(sb->s_flags & MS_RDONLY)) {
55                 sbi->s_mount_state |= EXT2_ERROR_FS;
56                 es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
57                 ext2_sync_super(sb, es);
58         }
59
60         va_start(args, fmt);
61         printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
62         vprintk(fmt, args);
63         printk("\n");
64         va_end(args);
65
66         if (test_opt(sb, ERRORS_PANIC))
67                 panic("EXT2-fs panic from previous error\n");
68         if (test_opt(sb, ERRORS_RO)) {
69                 printk("Remounting filesystem read-only\n");
70                 sb->s_flags |= MS_RDONLY;
71         }
72 }
73
74 void ext2_warning (struct super_block * sb, const char * function,
75                    const char * fmt, ...)
76 {
77         va_list args;
78
79         va_start(args, fmt);
80         printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
81                sb->s_id, function);
82         vprintk(fmt, args);
83         printk("\n");
84         va_end(args);
85 }
86
87 void ext2_update_dynamic_rev(struct super_block *sb)
88 {
89         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
90
91         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
92                 return;
93
94         ext2_warning(sb, __func__,
95                      "updating to rev %d because of new feature flag, "
96                      "running e2fsck is recommended",
97                      EXT2_DYNAMIC_REV);
98
99         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
100         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
101         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
102         /* leave es->s_feature_*compat flags alone */
103         /* es->s_uuid will be set by e2fsck if empty */
104
105         /*
106          * The rest of the superblock fields should be zero, and if not it
107          * means they are likely already in use, so leave them alone.  We
108          * can leave it up to e2fsck to clean up any inconsistencies there.
109          */
110 }
111
112 static void ext2_put_super (struct super_block * sb)
113 {
114         int db_count;
115         int i;
116         struct ext2_sb_info *sbi = EXT2_SB(sb);
117
118         lock_kernel();
119
120         if (sb->s_dirt)
121                 ext2_write_super(sb);
122
123         ext2_xattr_put_super(sb);
124         if (!(sb->s_flags & MS_RDONLY)) {
125                 struct ext2_super_block *es = sbi->s_es;
126
127                 es->s_state = cpu_to_le16(sbi->s_mount_state);
128                 ext2_sync_super(sb, es);
129         }
130         db_count = sbi->s_gdb_count;
131         for (i = 0; i < db_count; i++)
132                 if (sbi->s_group_desc[i])
133                         brelse (sbi->s_group_desc[i]);
134         kfree(sbi->s_group_desc);
135         kfree(sbi->s_debts);
136         percpu_counter_destroy(&sbi->s_freeblocks_counter);
137         percpu_counter_destroy(&sbi->s_freeinodes_counter);
138         percpu_counter_destroy(&sbi->s_dirs_counter);
139         brelse (sbi->s_sbh);
140         sb->s_fs_info = NULL;
141         kfree(sbi->s_blockgroup_lock);
142         kfree(sbi);
143
144         unlock_kernel();
145 }
146
147 static struct kmem_cache * ext2_inode_cachep;
148
149 static struct inode *ext2_alloc_inode(struct super_block *sb)
150 {
151         struct ext2_inode_info *ei;
152         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
153         if (!ei)
154                 return NULL;
155 #ifdef CONFIG_EXT2_FS_POSIX_ACL
156         ei->i_acl = EXT2_ACL_NOT_CACHED;
157         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
158 #endif
159         ei->i_block_alloc_info = NULL;
160         ei->vfs_inode.i_version = 1;
161         return &ei->vfs_inode;
162 }
163
164 static void ext2_destroy_inode(struct inode *inode)
165 {
166         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
167 }
168
169 static void init_once(void *foo)
170 {
171         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
172
173         rwlock_init(&ei->i_meta_lock);
174 #ifdef CONFIG_EXT2_FS_XATTR
175         init_rwsem(&ei->xattr_sem);
176 #endif
177         mutex_init(&ei->truncate_mutex);
178         inode_init_once(&ei->vfs_inode);
179 }
180
181 static int init_inodecache(void)
182 {
183         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
184                                              sizeof(struct ext2_inode_info),
185                                              0, (SLAB_RECLAIM_ACCOUNT|
186                                                 SLAB_MEM_SPREAD),
187                                              init_once);
188         if (ext2_inode_cachep == NULL)
189                 return -ENOMEM;
190         return 0;
191 }
192
193 static void destroy_inodecache(void)
194 {
195         kmem_cache_destroy(ext2_inode_cachep);
196 }
197
198 static void ext2_clear_inode(struct inode *inode)
199 {
200         struct ext2_block_alloc_info *rsv = EXT2_I(inode)->i_block_alloc_info;
201 #ifdef CONFIG_EXT2_FS_POSIX_ACL
202         struct ext2_inode_info *ei = EXT2_I(inode);
203
204         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
205                 posix_acl_release(ei->i_acl);
206                 ei->i_acl = EXT2_ACL_NOT_CACHED;
207         }
208         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
209                 posix_acl_release(ei->i_default_acl);
210                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
211         }
212 #endif
213         ext2_discard_reservation(inode);
214         EXT2_I(inode)->i_block_alloc_info = NULL;
215         if (unlikely(rsv))
216                 kfree(rsv);
217 }
218
219 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
220 {
221         struct super_block *sb = vfs->mnt_sb;
222         struct ext2_sb_info *sbi = EXT2_SB(sb);
223         struct ext2_super_block *es = sbi->s_es;
224         unsigned long def_mount_opts;
225
226         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
227
228         if (sbi->s_sb_block != 1)
229                 seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
230         if (test_opt(sb, MINIX_DF))
231                 seq_puts(seq, ",minixdf");
232         if (test_opt(sb, GRPID))
233                 seq_puts(seq, ",grpid");
234         if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
235                 seq_puts(seq, ",nogrpid");
236         if (sbi->s_resuid != EXT2_DEF_RESUID ||
237             le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
238                 seq_printf(seq, ",resuid=%u", sbi->s_resuid);
239         }
240         if (sbi->s_resgid != EXT2_DEF_RESGID ||
241             le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
242                 seq_printf(seq, ",resgid=%u", sbi->s_resgid);
243         }
244         if (test_opt(sb, ERRORS_RO)) {
245                 int def_errors = le16_to_cpu(es->s_errors);
246
247                 if (def_errors == EXT2_ERRORS_PANIC ||
248                     def_errors == EXT2_ERRORS_CONTINUE) {
249                         seq_puts(seq, ",errors=remount-ro");
250                 }
251         }
252         if (test_opt(sb, ERRORS_CONT))
253                 seq_puts(seq, ",errors=continue");
254         if (test_opt(sb, ERRORS_PANIC))
255                 seq_puts(seq, ",errors=panic");
256         if (test_opt(sb, NO_UID32))
257                 seq_puts(seq, ",nouid32");
258         if (test_opt(sb, DEBUG))
259                 seq_puts(seq, ",debug");
260         if (test_opt(sb, OLDALLOC))
261                 seq_puts(seq, ",oldalloc");
262
263 #ifdef CONFIG_EXT2_FS_XATTR
264         if (test_opt(sb, XATTR_USER))
265                 seq_puts(seq, ",user_xattr");
266         if (!test_opt(sb, XATTR_USER) &&
267             (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
268                 seq_puts(seq, ",nouser_xattr");
269         }
270 #endif
271
272 #ifdef CONFIG_EXT2_FS_POSIX_ACL
273         if (test_opt(sb, POSIX_ACL))
274                 seq_puts(seq, ",acl");
275         if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
276                 seq_puts(seq, ",noacl");
277 #endif
278
279         if (test_opt(sb, NOBH))
280                 seq_puts(seq, ",nobh");
281
282 #if defined(CONFIG_QUOTA)
283         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
284                 seq_puts(seq, ",usrquota");
285
286         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
287                 seq_puts(seq, ",grpquota");
288 #endif
289
290 #if defined(CONFIG_EXT2_FS_XIP)
291         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
292                 seq_puts(seq, ",xip");
293 #endif
294
295         if (!test_opt(sb, RESERVATION))
296                 seq_puts(seq, ",noreservation");
297
298         return 0;
299 }
300
301 #ifdef CONFIG_QUOTA
302 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
303 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
304 #endif
305
306 static const struct super_operations ext2_sops = {
307         .alloc_inode    = ext2_alloc_inode,
308         .destroy_inode  = ext2_destroy_inode,
309         .write_inode    = ext2_write_inode,
310         .delete_inode   = ext2_delete_inode,
311         .put_super      = ext2_put_super,
312         .write_super    = ext2_write_super,
313         .sync_fs        = ext2_sync_fs,
314         .statfs         = ext2_statfs,
315         .remount_fs     = ext2_remount,
316         .clear_inode    = ext2_clear_inode,
317         .show_options   = ext2_show_options,
318 #ifdef CONFIG_QUOTA
319         .quota_read     = ext2_quota_read,
320         .quota_write    = ext2_quota_write,
321 #endif
322 };
323
324 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
325                 u64 ino, u32 generation)
326 {
327         struct inode *inode;
328
329         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
330                 return ERR_PTR(-ESTALE);
331         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
332                 return ERR_PTR(-ESTALE);
333
334         /* iget isn't really right if the inode is currently unallocated!!
335          * ext2_read_inode currently does appropriate checks, but
336          * it might be "neater" to call ext2_get_inode first and check
337          * if the inode is valid.....
338          */
339         inode = ext2_iget(sb, ino);
340         if (IS_ERR(inode))
341                 return ERR_CAST(inode);
342         if (generation && inode->i_generation != generation) {
343                 /* we didn't find the right inode.. */
344                 iput(inode);
345                 return ERR_PTR(-ESTALE);
346         }
347         return inode;
348 }
349
350 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
351                 int fh_len, int fh_type)
352 {
353         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
354                                     ext2_nfs_get_inode);
355 }
356
357 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
358                 int fh_len, int fh_type)
359 {
360         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
361                                     ext2_nfs_get_inode);
362 }
363
364 /* Yes, most of these are left as NULL!!
365  * A NULL value implies the default, which works with ext2-like file
366  * systems, but can be improved upon.
367  * Currently only get_parent is required.
368  */
369 static const struct export_operations ext2_export_ops = {
370         .fh_to_dentry = ext2_fh_to_dentry,
371         .fh_to_parent = ext2_fh_to_parent,
372         .get_parent = ext2_get_parent,
373 };
374
375 static unsigned long get_sb_block(void **data)
376 {
377         unsigned long   sb_block;
378         char            *options = (char *) *data;
379
380         if (!options || strncmp(options, "sb=", 3) != 0)
381                 return 1;       /* Default location */
382         options += 3;
383         sb_block = simple_strtoul(options, &options, 0);
384         if (*options && *options != ',') {
385                 printk("EXT2-fs: Invalid sb specification: %s\n",
386                        (char *) *data);
387                 return 1;
388         }
389         if (*options == ',')
390                 options++;
391         *data = (void *) options;
392         return sb_block;
393 }
394
395 enum {
396         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
397         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
398         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
399         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
400         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
401         Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
402 };
403
404 static const match_table_t tokens = {
405         {Opt_bsd_df, "bsddf"},
406         {Opt_minix_df, "minixdf"},
407         {Opt_grpid, "grpid"},
408         {Opt_grpid, "bsdgroups"},
409         {Opt_nogrpid, "nogrpid"},
410         {Opt_nogrpid, "sysvgroups"},
411         {Opt_resgid, "resgid=%u"},
412         {Opt_resuid, "resuid=%u"},
413         {Opt_sb, "sb=%u"},
414         {Opt_err_cont, "errors=continue"},
415         {Opt_err_panic, "errors=panic"},
416         {Opt_err_ro, "errors=remount-ro"},
417         {Opt_nouid32, "nouid32"},
418         {Opt_nocheck, "check=none"},
419         {Opt_nocheck, "nocheck"},
420         {Opt_debug, "debug"},
421         {Opt_oldalloc, "oldalloc"},
422         {Opt_orlov, "orlov"},
423         {Opt_nobh, "nobh"},
424         {Opt_user_xattr, "user_xattr"},
425         {Opt_nouser_xattr, "nouser_xattr"},
426         {Opt_acl, "acl"},
427         {Opt_noacl, "noacl"},
428         {Opt_xip, "xip"},
429         {Opt_grpquota, "grpquota"},
430         {Opt_ignore, "noquota"},
431         {Opt_quota, "quota"},
432         {Opt_usrquota, "usrquota"},
433         {Opt_reservation, "reservation"},
434         {Opt_noreservation, "noreservation"},
435         {Opt_err, NULL}
436 };
437
438 static int parse_options (char * options,
439                           struct ext2_sb_info *sbi)
440 {
441         char * p;
442         substring_t args[MAX_OPT_ARGS];
443         int option;
444
445         if (!options)
446                 return 1;
447
448         while ((p = strsep (&options, ",")) != NULL) {
449                 int token;
450                 if (!*p)
451                         continue;
452
453                 token = match_token(p, tokens, args);
454                 switch (token) {
455                 case Opt_bsd_df:
456                         clear_opt (sbi->s_mount_opt, MINIX_DF);
457                         break;
458                 case Opt_minix_df:
459                         set_opt (sbi->s_mount_opt, MINIX_DF);
460                         break;
461                 case Opt_grpid:
462                         set_opt (sbi->s_mount_opt, GRPID);
463                         break;
464                 case Opt_nogrpid:
465                         clear_opt (sbi->s_mount_opt, GRPID);
466                         break;
467                 case Opt_resuid:
468                         if (match_int(&args[0], &option))
469                                 return 0;
470                         sbi->s_resuid = option;
471                         break;
472                 case Opt_resgid:
473                         if (match_int(&args[0], &option))
474                                 return 0;
475                         sbi->s_resgid = option;
476                         break;
477                 case Opt_sb:
478                         /* handled by get_sb_block() instead of here */
479                         /* *sb_block = match_int(&args[0]); */
480                         break;
481                 case Opt_err_panic:
482                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
483                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
484                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
485                         break;
486                 case Opt_err_ro:
487                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
488                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
489                         set_opt (sbi->s_mount_opt, ERRORS_RO);
490                         break;
491                 case Opt_err_cont:
492                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
493                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
494                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
495                         break;
496                 case Opt_nouid32:
497                         set_opt (sbi->s_mount_opt, NO_UID32);
498                         break;
499                 case Opt_nocheck:
500                         clear_opt (sbi->s_mount_opt, CHECK);
501                         break;
502                 case Opt_debug:
503                         set_opt (sbi->s_mount_opt, DEBUG);
504                         break;
505                 case Opt_oldalloc:
506                         set_opt (sbi->s_mount_opt, OLDALLOC);
507                         break;
508                 case Opt_orlov:
509                         clear_opt (sbi->s_mount_opt, OLDALLOC);
510                         break;
511                 case Opt_nobh:
512                         set_opt (sbi->s_mount_opt, NOBH);
513                         break;
514 #ifdef CONFIG_EXT2_FS_XATTR
515                 case Opt_user_xattr:
516                         set_opt (sbi->s_mount_opt, XATTR_USER);
517                         break;
518                 case Opt_nouser_xattr:
519                         clear_opt (sbi->s_mount_opt, XATTR_USER);
520                         break;
521 #else
522                 case Opt_user_xattr:
523                 case Opt_nouser_xattr:
524                         printk("EXT2 (no)user_xattr options not supported\n");
525                         break;
526 #endif
527 #ifdef CONFIG_EXT2_FS_POSIX_ACL
528                 case Opt_acl:
529                         set_opt(sbi->s_mount_opt, POSIX_ACL);
530                         break;
531                 case Opt_noacl:
532                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
533                         break;
534 #else
535                 case Opt_acl:
536                 case Opt_noacl:
537                         printk("EXT2 (no)acl options not supported\n");
538                         break;
539 #endif
540                 case Opt_xip:
541 #ifdef CONFIG_EXT2_FS_XIP
542                         set_opt (sbi->s_mount_opt, XIP);
543 #else
544                         printk("EXT2 xip option not supported\n");
545 #endif
546                         break;
547
548 #if defined(CONFIG_QUOTA)
549                 case Opt_quota:
550                 case Opt_usrquota:
551                         set_opt(sbi->s_mount_opt, USRQUOTA);
552                         break;
553
554                 case Opt_grpquota:
555                         set_opt(sbi->s_mount_opt, GRPQUOTA);
556                         break;
557 #else
558                 case Opt_quota:
559                 case Opt_usrquota:
560                 case Opt_grpquota:
561                         printk(KERN_ERR
562                                 "EXT2-fs: quota operations not supported.\n");
563
564                         break;
565 #endif
566
567                 case Opt_reservation:
568                         set_opt(sbi->s_mount_opt, RESERVATION);
569                         printk("reservations ON\n");
570                         break;
571                 case Opt_noreservation:
572                         clear_opt(sbi->s_mount_opt, RESERVATION);
573                         printk("reservations OFF\n");
574                         break;
575                 case Opt_ignore:
576                         break;
577                 default:
578                         return 0;
579                 }
580         }
581         return 1;
582 }
583
584 static int ext2_setup_super (struct super_block * sb,
585                               struct ext2_super_block * es,
586                               int read_only)
587 {
588         int res = 0;
589         struct ext2_sb_info *sbi = EXT2_SB(sb);
590
591         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
592                 printk ("EXT2-fs warning: revision level too high, "
593                         "forcing read-only mode\n");
594                 res = MS_RDONLY;
595         }
596         if (read_only)
597                 return res;
598         if (!(sbi->s_mount_state & EXT2_VALID_FS))
599                 printk ("EXT2-fs warning: mounting unchecked fs, "
600                         "running e2fsck is recommended\n");
601         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
602                 printk ("EXT2-fs warning: mounting fs with errors, "
603                         "running e2fsck is recommended\n");
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                 printk ("EXT2-fs warning: maximal mount count reached, "
608                         "running e2fsck is recommended\n");
609         else if (le32_to_cpu(es->s_checkinterval) &&
610                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
611                 printk ("EXT2-fs warning: checktime reached, "
612                         "running e2fsck is recommended\n");
613         if (!le16_to_cpu(es->s_max_mnt_count))
614                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
615         le16_add_cpu(&es->s_mnt_count, 1);
616         ext2_write_super(sb);
617         if (test_opt (sb, DEBUG))
618                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
619                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
620                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
621                         sbi->s_frag_size,
622                         sbi->s_groups_count,
623                         EXT2_BLOCKS_PER_GROUP(sb),
624                         EXT2_INODES_PER_GROUP(sb),
625                         sbi->s_mount_opt);
626         return res;
627 }
628
629 static int ext2_check_descriptors(struct super_block *sb)
630 {
631         int i;
632         struct ext2_sb_info *sbi = EXT2_SB(sb);
633
634         ext2_debug ("Checking group descriptors");
635
636         for (i = 0; i < sbi->s_groups_count; i++) {
637                 struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
638                 ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
639                 ext2_fsblk_t last_block;
640
641                 if (i == sbi->s_groups_count - 1)
642                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
643                 else
644                         last_block = first_block +
645                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
646
647                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
648                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
649                 {
650                         ext2_error (sb, "ext2_check_descriptors",
651                                     "Block bitmap for group %d"
652                                     " not in group (block %lu)!",
653                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
654                         return 0;
655                 }
656                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
657                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
658                 {
659                         ext2_error (sb, "ext2_check_descriptors",
660                                     "Inode bitmap for group %d"
661                                     " not in group (block %lu)!",
662                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
663                         return 0;
664                 }
665                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
666                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
667                     last_block)
668                 {
669                         ext2_error (sb, "ext2_check_descriptors",
670                                     "Inode table for group %d"
671                                     " not in group (block %lu)!",
672                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
673                         return 0;
674                 }
675         }
676         return 1;
677 }
678
679 /*
680  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
681  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
682  * We need to be 1 filesystem block less than the 2^32 sector limit.
683  */
684 static loff_t ext2_max_size(int bits)
685 {
686         loff_t res = EXT2_NDIR_BLOCKS;
687         int meta_blocks;
688         loff_t upper_limit;
689
690         /* This is calculated to be the largest file size for a
691          * dense, file such that the total number of
692          * sectors in the file, including data and all indirect blocks,
693          * does not exceed 2^32 -1
694          * __u32 i_blocks representing the total number of
695          * 512 bytes blocks of the file
696          */
697         upper_limit = (1LL << 32) - 1;
698
699         /* total blocks in file system block size */
700         upper_limit >>= (bits - 9);
701
702
703         /* indirect blocks */
704         meta_blocks = 1;
705         /* double indirect blocks */
706         meta_blocks += 1 + (1LL << (bits-2));
707         /* tripple indirect blocks */
708         meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
709
710         upper_limit -= meta_blocks;
711         upper_limit <<= bits;
712
713         res += 1LL << (bits-2);
714         res += 1LL << (2*(bits-2));
715         res += 1LL << (3*(bits-2));
716         res <<= bits;
717         if (res > upper_limit)
718                 res = upper_limit;
719
720         if (res > MAX_LFS_FILESIZE)
721                 res = MAX_LFS_FILESIZE;
722
723         return res;
724 }
725
726 static unsigned long descriptor_loc(struct super_block *sb,
727                                     unsigned long logic_sb_block,
728                                     int nr)
729 {
730         struct ext2_sb_info *sbi = EXT2_SB(sb);
731         unsigned long bg, first_meta_bg;
732         int has_super = 0;
733         
734         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
735
736         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
737             nr < first_meta_bg)
738                 return (logic_sb_block + nr + 1);
739         bg = sbi->s_desc_per_block * nr;
740         if (ext2_bg_has_super(sb, bg))
741                 has_super = 1;
742
743         return ext2_group_first_block_no(sb, bg) + has_super;
744 }
745
746 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
747 {
748         struct buffer_head * bh;
749         struct ext2_sb_info * sbi;
750         struct ext2_super_block * es;
751         struct inode *root;
752         unsigned long block;
753         unsigned long sb_block = get_sb_block(&data);
754         unsigned long logic_sb_block;
755         unsigned long offset = 0;
756         unsigned long def_mount_opts;
757         long ret = -EINVAL;
758         int blocksize = BLOCK_SIZE;
759         int db_count;
760         int i, j;
761         __le32 features;
762         int err;
763
764         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
765         if (!sbi)
766                 return -ENOMEM;
767
768         sbi->s_blockgroup_lock =
769                 kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
770         if (!sbi->s_blockgroup_lock) {
771                 kfree(sbi);
772                 return -ENOMEM;
773         }
774         sb->s_fs_info = sbi;
775         sbi->s_sb_block = sb_block;
776
777         /*
778          * See what the current blocksize for the device is, and
779          * use that as the blocksize.  Otherwise (or if the blocksize
780          * is smaller than the default) use the default.
781          * This is important for devices that have a hardware
782          * sectorsize that is larger than the default.
783          */
784         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
785         if (!blocksize) {
786                 printk ("EXT2-fs: unable to set blocksize\n");
787                 goto failed_sbi;
788         }
789
790         /*
791          * If the superblock doesn't start on a hardware sector boundary,
792          * calculate the offset.  
793          */
794         if (blocksize != BLOCK_SIZE) {
795                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
796                 offset = (sb_block*BLOCK_SIZE) % blocksize;
797         } else {
798                 logic_sb_block = sb_block;
799         }
800
801         if (!(bh = sb_bread(sb, logic_sb_block))) {
802                 printk ("EXT2-fs: unable to read superblock\n");
803                 goto failed_sbi;
804         }
805         /*
806          * Note: s_es must be initialized as soon as possible because
807          *       some ext2 macro-instructions depend on its value
808          */
809         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
810         sbi->s_es = es;
811         sb->s_magic = le16_to_cpu(es->s_magic);
812
813         if (sb->s_magic != EXT2_SUPER_MAGIC)
814                 goto cantfind_ext2;
815
816         /* Set defaults before we parse the mount options */
817         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
818         if (def_mount_opts & EXT2_DEFM_DEBUG)
819                 set_opt(sbi->s_mount_opt, DEBUG);
820         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
821                 set_opt(sbi->s_mount_opt, GRPID);
822         if (def_mount_opts & EXT2_DEFM_UID16)
823                 set_opt(sbi->s_mount_opt, NO_UID32);
824 #ifdef CONFIG_EXT2_FS_XATTR
825         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
826                 set_opt(sbi->s_mount_opt, XATTR_USER);
827 #endif
828 #ifdef CONFIG_EXT2_FS_POSIX_ACL
829         if (def_mount_opts & EXT2_DEFM_ACL)
830                 set_opt(sbi->s_mount_opt, POSIX_ACL);
831 #endif
832         
833         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
834                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
835         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
836                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
837         else
838                 set_opt(sbi->s_mount_opt, ERRORS_RO);
839
840         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
841         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
842         
843         set_opt(sbi->s_mount_opt, RESERVATION);
844
845         if (!parse_options ((char *) data, sbi))
846                 goto failed_mount;
847
848         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
849                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
850                  MS_POSIXACL : 0);
851
852         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
853                                     EXT2_MOUNT_XIP if not */
854
855         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
856             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
857              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
858              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
859                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
860                        "running e2fsck is recommended\n");
861         /*
862          * Check feature flags regardless of the revision level, since we
863          * previously didn't change the revision level when setting the flags,
864          * so there is a chance incompat flags are set on a rev 0 filesystem.
865          */
866         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
867         if (features) {
868                 printk("EXT2-fs: %s: couldn't mount because of "
869                        "unsupported optional features (%x).\n",
870                        sb->s_id, le32_to_cpu(features));
871                 goto failed_mount;
872         }
873         if (!(sb->s_flags & MS_RDONLY) &&
874             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
875                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
876                        "unsupported optional features (%x).\n",
877                        sb->s_id, le32_to_cpu(features));
878                 goto failed_mount;
879         }
880
881         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
882
883         if (ext2_use_xip(sb) && blocksize != PAGE_SIZE) {
884                 if (!silent)
885                         printk("XIP: Unsupported blocksize\n");
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                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
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                         printk("EXT2-fs: Couldn't read superblock on "
903                                "2nd try.\n");
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                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
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                         printk ("EXT2-fs: unsupported inode size: %d\n",
926                                 sbi->s_inode_size);
927                         goto failed_mount;
928                 }
929         }
930
931         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
932                                    le32_to_cpu(es->s_log_frag_size);
933         if (sbi->s_frag_size == 0)
934                 goto cantfind_ext2;
935         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
936
937         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
938         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
939         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
940
941         if (EXT2_INODE_SIZE(sb) == 0)
942                 goto cantfind_ext2;
943         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
944         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
945                 goto cantfind_ext2;
946         sbi->s_itb_per_group = sbi->s_inodes_per_group /
947                                         sbi->s_inodes_per_block;
948         sbi->s_desc_per_block = sb->s_blocksize /
949                                         sizeof (struct ext2_group_desc);
950         sbi->s_sbh = bh;
951         sbi->s_mount_state = le16_to_cpu(es->s_state);
952         sbi->s_addr_per_block_bits =
953                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
954         sbi->s_desc_per_block_bits =
955                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
956
957         if (sb->s_magic != EXT2_SUPER_MAGIC)
958                 goto cantfind_ext2;
959
960         if (sb->s_blocksize != bh->b_size) {
961                 if (!silent)
962                         printk ("VFS: Unsupported blocksize on dev "
963                                 "%s.\n", sb->s_id);
964                 goto failed_mount;
965         }
966
967         if (sb->s_blocksize != sbi->s_frag_size) {
968                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
969                         sbi->s_frag_size, sb->s_blocksize);
970                 goto failed_mount;
971         }
972
973         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
974                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
975                         sbi->s_blocks_per_group);
976                 goto failed_mount;
977         }
978         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
979                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
980                         sbi->s_frags_per_group);
981                 goto failed_mount;
982         }
983         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
984                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
985                         sbi->s_inodes_per_group);
986                 goto failed_mount;
987         }
988
989         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
990                 goto cantfind_ext2;
991         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
992                                 le32_to_cpu(es->s_first_data_block) - 1)
993                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
994         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
995                    EXT2_DESC_PER_BLOCK(sb);
996         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
997         if (sbi->s_group_desc == NULL) {
998                 printk ("EXT2-fs: not enough memory\n");
999                 goto failed_mount;
1000         }
1001         bgl_lock_init(sbi->s_blockgroup_lock);
1002         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1003         if (!sbi->s_debts) {
1004                 printk ("EXT2-fs: not enough memory\n");
1005                 goto failed_mount_group_desc;
1006         }
1007         for (i = 0; i < db_count; i++) {
1008                 block = descriptor_loc(sb, logic_sb_block, i);
1009                 sbi->s_group_desc[i] = sb_bread(sb, block);
1010                 if (!sbi->s_group_desc[i]) {
1011                         for (j = 0; j < i; j++)
1012                                 brelse (sbi->s_group_desc[j]);
1013                         printk ("EXT2-fs: unable to read group descriptors\n");
1014                         goto failed_mount_group_desc;
1015                 }
1016         }
1017         if (!ext2_check_descriptors (sb)) {
1018                 printk ("EXT2-fs: group descriptors corrupted!\n");
1019                 goto failed_mount2;
1020         }
1021         sbi->s_gdb_count = db_count;
1022         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1023         spin_lock_init(&sbi->s_next_gen_lock);
1024
1025         /* per fileystem reservation list head & lock */
1026         spin_lock_init(&sbi->s_rsv_window_lock);
1027         sbi->s_rsv_window_root = RB_ROOT;
1028         /*
1029          * Add a single, static dummy reservation to the start of the
1030          * reservation window list --- it gives us a placeholder for
1031          * append-at-start-of-list which makes the allocation logic
1032          * _much_ simpler.
1033          */
1034         sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1035         sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1036         sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1037         sbi->s_rsv_window_head.rsv_goal_size = 0;
1038         ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1039
1040         err = percpu_counter_init(&sbi->s_freeblocks_counter,
1041                                 ext2_count_free_blocks(sb));
1042         if (!err) {
1043                 err = percpu_counter_init(&sbi->s_freeinodes_counter,
1044                                 ext2_count_free_inodes(sb));
1045         }
1046         if (!err) {
1047                 err = percpu_counter_init(&sbi->s_dirs_counter,
1048                                 ext2_count_dirs(sb));
1049         }
1050         if (err) {
1051                 printk(KERN_ERR "EXT2-fs: insufficient memory\n");
1052                 goto failed_mount3;
1053         }
1054         /*
1055          * set up enough so that it can read an inode
1056          */
1057         sb->s_op = &ext2_sops;
1058         sb->s_export_op = &ext2_export_ops;
1059         sb->s_xattr = ext2_xattr_handlers;
1060         root = ext2_iget(sb, EXT2_ROOT_INO);
1061         if (IS_ERR(root)) {
1062                 ret = PTR_ERR(root);
1063                 goto failed_mount3;
1064         }
1065         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1066                 iput(root);
1067                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
1068                 goto failed_mount3;
1069         }
1070
1071         sb->s_root = d_alloc_root(root);
1072         if (!sb->s_root) {
1073                 iput(root);
1074                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
1075                 ret = -ENOMEM;
1076                 goto failed_mount3;
1077         }
1078         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1079                 ext2_warning(sb, __func__,
1080                         "mounting ext3 filesystem as ext2");
1081         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
1082         return 0;
1083
1084 cantfind_ext2:
1085         if (!silent)
1086                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
1087                        sb->s_id);
1088         goto failed_mount;
1089 failed_mount3:
1090         percpu_counter_destroy(&sbi->s_freeblocks_counter);
1091         percpu_counter_destroy(&sbi->s_freeinodes_counter);
1092         percpu_counter_destroy(&sbi->s_dirs_counter);
1093 failed_mount2:
1094         for (i = 0; i < db_count; i++)
1095                 brelse(sbi->s_group_desc[i]);
1096 failed_mount_group_desc:
1097         kfree(sbi->s_group_desc);
1098         kfree(sbi->s_debts);
1099 failed_mount:
1100         brelse(bh);
1101 failed_sbi:
1102         sb->s_fs_info = NULL;
1103         kfree(sbi->s_blockgroup_lock);
1104         kfree(sbi);
1105         return ret;
1106 }
1107
1108 static void ext2_commit_super (struct super_block * sb,
1109                                struct ext2_super_block * es)
1110 {
1111         es->s_wtime = cpu_to_le32(get_seconds());
1112         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1113         sb->s_dirt = 0;
1114 }
1115
1116 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
1117 {
1118         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1119         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1120         es->s_wtime = cpu_to_le32(get_seconds());
1121         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1122         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1123         sb->s_dirt = 0;
1124 }
1125
1126 /*
1127  * In the second extended file system, it is not necessary to
1128  * write the super block since we use a mapping of the
1129  * disk super block in a buffer.
1130  *
1131  * However, this function is still used to set the fs valid
1132  * flags to 0.  We need to set this flag to 0 since the fs
1133  * may have been checked while mounted and e2fsck may have
1134  * set s_state to EXT2_VALID_FS after some corrections.
1135  */
1136
1137 static int ext2_sync_fs(struct super_block *sb, int wait)
1138 {
1139         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1140
1141         lock_kernel();
1142         if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1143                 ext2_debug("setting valid to 0\n");
1144                 es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1145                 es->s_free_blocks_count =
1146                         cpu_to_le32(ext2_count_free_blocks(sb));
1147                 es->s_free_inodes_count =
1148                         cpu_to_le32(ext2_count_free_inodes(sb));
1149                 es->s_mtime = cpu_to_le32(get_seconds());
1150                 ext2_sync_super(sb, es);
1151         } else {
1152                 ext2_commit_super(sb, es);
1153         }
1154         sb->s_dirt = 0;
1155         unlock_kernel();
1156
1157         return 0;
1158 }
1159
1160
1161 void ext2_write_super(struct super_block *sb)
1162 {
1163         if (!(sb->s_flags & MS_RDONLY))
1164                 ext2_sync_fs(sb, 1);
1165         else
1166                 sb->s_dirt = 0;
1167 }
1168
1169 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1170 {
1171         struct ext2_sb_info * sbi = EXT2_SB(sb);
1172         struct ext2_super_block * es;
1173         unsigned long old_mount_opt = sbi->s_mount_opt;
1174         struct ext2_mount_options old_opts;
1175         unsigned long old_sb_flags;
1176         int err;
1177
1178         lock_kernel();
1179
1180         /* Store the old options */
1181         old_sb_flags = sb->s_flags;
1182         old_opts.s_mount_opt = sbi->s_mount_opt;
1183         old_opts.s_resuid = sbi->s_resuid;
1184         old_opts.s_resgid = sbi->s_resgid;
1185
1186         /*
1187          * Allow the "check" option to be passed as a remount option.
1188          */
1189         if (!parse_options (data, sbi)) {
1190                 err = -EINVAL;
1191                 goto restore_opts;
1192         }
1193
1194         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1195                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1196
1197         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1198                                     EXT2_MOUNT_XIP if not */
1199
1200         if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1201                 printk("XIP: Unsupported blocksize\n");
1202                 err = -EINVAL;
1203                 goto restore_opts;
1204         }
1205
1206         es = sbi->s_es;
1207         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1208             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1209             invalidate_inodes(sb)) {
1210                 ext2_warning(sb, __func__, "refusing change of xip flag "
1211                              "with busy inodes while remounting");
1212                 sbi->s_mount_opt &= ~EXT2_MOUNT_XIP;
1213                 sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;
1214         }
1215         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
1216                 unlock_kernel();
1217                 return 0;
1218         }
1219         if (*flags & MS_RDONLY) {
1220                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1221                     !(sbi->s_mount_state & EXT2_VALID_FS)) {
1222                         unlock_kernel();
1223                         return 0;
1224                 }
1225                 /*
1226                  * OK, we are remounting a valid rw partition rdonly, so set
1227                  * the rdonly flag and then mark the partition as valid again.
1228                  */
1229                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1230                 es->s_mtime = cpu_to_le32(get_seconds());
1231         } else {
1232                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1233                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1234                 if (ret) {
1235                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1236                                "unsupported optional features (%x).\n",
1237                                sb->s_id, le32_to_cpu(ret));
1238                         err = -EROFS;
1239                         goto restore_opts;
1240                 }
1241                 /*
1242                  * Mounting a RDONLY partition read-write, so reread and
1243                  * store the current valid flag.  (It may have been changed
1244                  * by e2fsck since we originally mounted the partition.)
1245                  */
1246                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1247                 if (!ext2_setup_super (sb, es, 0))
1248                         sb->s_flags &= ~MS_RDONLY;
1249         }
1250         ext2_sync_super(sb, es);
1251         unlock_kernel();
1252         return 0;
1253 restore_opts:
1254         sbi->s_mount_opt = old_opts.s_mount_opt;
1255         sbi->s_resuid = old_opts.s_resuid;
1256         sbi->s_resgid = old_opts.s_resgid;
1257         sb->s_flags = old_sb_flags;
1258         unlock_kernel();
1259         return err;
1260 }
1261
1262 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1263 {
1264         struct super_block *sb = dentry->d_sb;
1265         struct ext2_sb_info *sbi = EXT2_SB(sb);
1266         struct ext2_super_block *es = sbi->s_es;
1267         u64 fsid;
1268
1269         if (test_opt (sb, MINIX_DF))
1270                 sbi->s_overhead_last = 0;
1271         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1272                 unsigned long i, overhead = 0;
1273                 smp_rmb();
1274
1275                 /*
1276                  * Compute the overhead (FS structures). This is constant
1277                  * for a given filesystem unless the number of block groups
1278                  * changes so we cache the previous value until it does.
1279                  */
1280
1281                 /*
1282                  * All of the blocks before first_data_block are
1283                  * overhead
1284                  */
1285                 overhead = le32_to_cpu(es->s_first_data_block);
1286
1287                 /*
1288                  * Add the overhead attributed to the superblock and
1289                  * block group descriptors.  If the sparse superblocks
1290                  * feature is turned on, then not all groups have this.
1291                  */
1292                 for (i = 0; i < sbi->s_groups_count; i++)
1293                         overhead += ext2_bg_has_super(sb, i) +
1294                                 ext2_bg_num_gdb(sb, i);
1295
1296                 /*
1297                  * Every block group has an inode bitmap, a block
1298                  * bitmap, and an inode table.
1299                  */
1300                 overhead += (sbi->s_groups_count *
1301                              (2 + sbi->s_itb_per_group));
1302                 sbi->s_overhead_last = overhead;
1303                 smp_wmb();
1304                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1305         }
1306
1307         buf->f_type = EXT2_SUPER_MAGIC;
1308         buf->f_bsize = sb->s_blocksize;
1309         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1310         buf->f_bfree = ext2_count_free_blocks(sb);
1311         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1312         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1313         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1314                 buf->f_bavail = 0;
1315         buf->f_files = le32_to_cpu(es->s_inodes_count);
1316         buf->f_ffree = ext2_count_free_inodes(sb);
1317         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1318         buf->f_namelen = EXT2_NAME_LEN;
1319         fsid = le64_to_cpup((void *)es->s_uuid) ^
1320                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1321         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1322         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1323         return 0;
1324 }
1325
1326 static int ext2_get_sb(struct file_system_type *fs_type,
1327         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1328 {
1329         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1330 }
1331
1332 #ifdef CONFIG_QUOTA
1333
1334 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1335  * acquiring the locks... As quota files are never truncated and quota code
1336  * itself serializes the operations (and noone else should touch the files)
1337  * we don't have to be afraid of races */
1338 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1339                                size_t len, loff_t off)
1340 {
1341         struct inode *inode = sb_dqopt(sb)->files[type];
1342         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1343         int err = 0;
1344         int offset = off & (sb->s_blocksize - 1);
1345         int tocopy;
1346         size_t toread;
1347         struct buffer_head tmp_bh;
1348         struct buffer_head *bh;
1349         loff_t i_size = i_size_read(inode);
1350
1351         if (off > i_size)
1352                 return 0;
1353         if (off+len > i_size)
1354                 len = i_size-off;
1355         toread = len;
1356         while (toread > 0) {
1357                 tocopy = sb->s_blocksize - offset < toread ?
1358                                 sb->s_blocksize - offset : toread;
1359
1360                 tmp_bh.b_state = 0;
1361                 tmp_bh.b_size = sb->s_blocksize;
1362                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1363                 if (err < 0)
1364                         return err;
1365                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1366                         memset(data, 0, tocopy);
1367                 else {
1368                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1369                         if (!bh)
1370                                 return -EIO;
1371                         memcpy(data, bh->b_data+offset, tocopy);
1372                         brelse(bh);
1373                 }
1374                 offset = 0;
1375                 toread -= tocopy;
1376                 data += tocopy;
1377                 blk++;
1378         }
1379         return len;
1380 }
1381
1382 /* Write to quotafile */
1383 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1384                                 const char *data, size_t len, loff_t off)
1385 {
1386         struct inode *inode = sb_dqopt(sb)->files[type];
1387         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1388         int err = 0;
1389         int offset = off & (sb->s_blocksize - 1);
1390         int tocopy;
1391         size_t towrite = len;
1392         struct buffer_head tmp_bh;
1393         struct buffer_head *bh;
1394
1395         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1396         while (towrite > 0) {
1397                 tocopy = sb->s_blocksize - offset < towrite ?
1398                                 sb->s_blocksize - offset : towrite;
1399
1400                 tmp_bh.b_state = 0;
1401                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1402                 if (err < 0)
1403                         goto out;
1404                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1405                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1406                 else
1407                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1408                 if (!bh) {
1409                         err = -EIO;
1410                         goto out;
1411                 }
1412                 lock_buffer(bh);
1413                 memcpy(bh->b_data+offset, data, tocopy);
1414                 flush_dcache_page(bh->b_page);
1415                 set_buffer_uptodate(bh);
1416                 mark_buffer_dirty(bh);
1417                 unlock_buffer(bh);
1418                 brelse(bh);
1419                 offset = 0;
1420                 towrite -= tocopy;
1421                 data += tocopy;
1422                 blk++;
1423         }
1424 out:
1425         if (len == towrite) {
1426                 mutex_unlock(&inode->i_mutex);
1427                 return err;
1428         }
1429         if (inode->i_size < off+len-towrite)
1430                 i_size_write(inode, off+len-towrite);
1431         inode->i_version++;
1432         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1433         mark_inode_dirty(inode);
1434         mutex_unlock(&inode->i_mutex);
1435         return len - towrite;
1436 }
1437
1438 #endif
1439
1440 static struct file_system_type ext2_fs_type = {
1441         .owner          = THIS_MODULE,
1442         .name           = "ext2",
1443         .get_sb         = ext2_get_sb,
1444         .kill_sb        = kill_block_super,
1445         .fs_flags       = FS_REQUIRES_DEV,
1446 };
1447
1448 static int __init init_ext2_fs(void)
1449 {
1450         int err = init_ext2_xattr();
1451         if (err)
1452                 return err;
1453         err = init_inodecache();
1454         if (err)
1455                 goto out1;
1456         err = register_filesystem(&ext2_fs_type);
1457         if (err)
1458                 goto out;
1459         return 0;
1460 out:
1461         destroy_inodecache();
1462 out1:
1463         exit_ext2_xattr();
1464         return err;
1465 }
1466
1467 static void __exit exit_ext2_fs(void)
1468 {
1469         unregister_filesystem(&ext2_fs_type);
1470         destroy_inodecache();
1471         exit_ext2_xattr();
1472 }
1473
1474 module_init(init_ext2_fs)
1475 module_exit(exit_ext2_fs)