exportfs: make struct export_operations const
[linux-2.6.git] / fs / ext2 / super.c
1 /*
2  *  linux/fs/ext2/super.c
3  *
4  * Copyright (C) 1992, 1993, 1994, 1995
5  * Remy Card (card@masi.ibp.fr)
6  * Laboratoire MASI - Institut Blaise Pascal
7  * Universite Pierre et Marie Curie (Paris VI)
8  *
9  *  from
10  *
11  *  linux/fs/minix/inode.c
12  *
13  *  Copyright (C) 1991, 1992  Linus Torvalds
14  *
15  *  Big-endian to little-endian byte-swapping/bitmaps by
16  *        David S. Miller (davem@caip.rutgers.edu), 1995
17  */
18
19 #include <linux/module.h>
20 #include <linux/string.h>
21 #include <linux/fs.h>
22 #include <linux/slab.h>
23 #include <linux/init.h>
24 #include <linux/blkdev.h>
25 #include <linux/parser.h>
26 #include <linux/random.h>
27 #include <linux/buffer_head.h>
28 #include <linux/exportfs.h>
29 #include <linux/smp_lock.h>
30 #include <linux/vfs.h>
31 #include <linux/seq_file.h>
32 #include <linux/mount.h>
33 #include <linux/log2.h>
34 #include <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);
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
45 void ext2_error (struct super_block * sb, const char * function,
46                  const char * fmt, ...)
47 {
48         va_list args;
49         struct ext2_sb_info *sbi = EXT2_SB(sb);
50         struct ext2_super_block *es = sbi->s_es;
51
52         if (!(sb->s_flags & MS_RDONLY)) {
53                 sbi->s_mount_state |= EXT2_ERROR_FS;
54                 es->s_state =
55                         cpu_to_le16(le16_to_cpu(es->s_state) | EXT2_ERROR_FS);
56                 ext2_sync_super(sb, es);
57         }
58
59         va_start(args, fmt);
60         printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
61         vprintk(fmt, args);
62         printk("\n");
63         va_end(args);
64
65         if (test_opt(sb, ERRORS_PANIC))
66                 panic("EXT2-fs panic from previous error\n");
67         if (test_opt(sb, ERRORS_RO)) {
68                 printk("Remounting filesystem read-only\n");
69                 sb->s_flags |= MS_RDONLY;
70         }
71 }
72
73 void ext2_warning (struct super_block * sb, const char * function,
74                    const char * fmt, ...)
75 {
76         va_list args;
77
78         va_start(args, fmt);
79         printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
80                sb->s_id, function);
81         vprintk(fmt, args);
82         printk("\n");
83         va_end(args);
84 }
85
86 void ext2_update_dynamic_rev(struct super_block *sb)
87 {
88         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
89
90         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
91                 return;
92
93         ext2_warning(sb, __FUNCTION__,
94                      "updating to rev %d because of new feature flag, "
95                      "running e2fsck is recommended",
96                      EXT2_DYNAMIC_REV);
97
98         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
99         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
100         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
101         /* leave es->s_feature_*compat flags alone */
102         /* es->s_uuid will be set by e2fsck if empty */
103
104         /*
105          * The rest of the superblock fields should be zero, and if not it
106          * means they are likely already in use, so leave them alone.  We
107          * can leave it up to e2fsck to clean up any inconsistencies there.
108          */
109 }
110
111 static void ext2_put_super (struct super_block * sb)
112 {
113         int db_count;
114         int i;
115         struct ext2_sb_info *sbi = EXT2_SB(sb);
116
117         ext2_xattr_put_super(sb);
118         if (!(sb->s_flags & MS_RDONLY)) {
119                 struct ext2_super_block *es = sbi->s_es;
120
121                 es->s_state = cpu_to_le16(sbi->s_mount_state);
122                 ext2_sync_super(sb, es);
123         }
124         db_count = sbi->s_gdb_count;
125         for (i = 0; i < db_count; i++)
126                 if (sbi->s_group_desc[i])
127                         brelse (sbi->s_group_desc[i]);
128         kfree(sbi->s_group_desc);
129         kfree(sbi->s_debts);
130         percpu_counter_destroy(&sbi->s_freeblocks_counter);
131         percpu_counter_destroy(&sbi->s_freeinodes_counter);
132         percpu_counter_destroy(&sbi->s_dirs_counter);
133         brelse (sbi->s_sbh);
134         sb->s_fs_info = NULL;
135         kfree(sbi);
136
137         return;
138 }
139
140 static struct kmem_cache * ext2_inode_cachep;
141
142 static struct inode *ext2_alloc_inode(struct super_block *sb)
143 {
144         struct ext2_inode_info *ei;
145         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
146         if (!ei)
147                 return NULL;
148 #ifdef CONFIG_EXT2_FS_POSIX_ACL
149         ei->i_acl = EXT2_ACL_NOT_CACHED;
150         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
151 #endif
152         ei->i_block_alloc_info = NULL;
153         ei->vfs_inode.i_version = 1;
154         return &ei->vfs_inode;
155 }
156
157 static void ext2_destroy_inode(struct inode *inode)
158 {
159         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
160 }
161
162 static void init_once(struct kmem_cache * cachep, void *foo)
163 {
164         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
165
166         rwlock_init(&ei->i_meta_lock);
167 #ifdef CONFIG_EXT2_FS_XATTR
168         init_rwsem(&ei->xattr_sem);
169 #endif
170         mutex_init(&ei->truncate_mutex);
171         inode_init_once(&ei->vfs_inode);
172 }
173
174 static int init_inodecache(void)
175 {
176         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
177                                              sizeof(struct ext2_inode_info),
178                                              0, (SLAB_RECLAIM_ACCOUNT|
179                                                 SLAB_MEM_SPREAD),
180                                              init_once);
181         if (ext2_inode_cachep == NULL)
182                 return -ENOMEM;
183         return 0;
184 }
185
186 static void destroy_inodecache(void)
187 {
188         kmem_cache_destroy(ext2_inode_cachep);
189 }
190
191 static void ext2_clear_inode(struct inode *inode)
192 {
193         struct ext2_block_alloc_info *rsv = EXT2_I(inode)->i_block_alloc_info;
194 #ifdef CONFIG_EXT2_FS_POSIX_ACL
195         struct ext2_inode_info *ei = EXT2_I(inode);
196
197         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
198                 posix_acl_release(ei->i_acl);
199                 ei->i_acl = EXT2_ACL_NOT_CACHED;
200         }
201         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
202                 posix_acl_release(ei->i_default_acl);
203                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
204         }
205 #endif
206         ext2_discard_reservation(inode);
207         EXT2_I(inode)->i_block_alloc_info = NULL;
208         if (unlikely(rsv))
209                 kfree(rsv);
210 }
211
212 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
213 {
214         struct super_block *sb = vfs->mnt_sb;
215         struct ext2_sb_info *sbi = EXT2_SB(sb);
216         struct ext2_super_block *es = sbi->s_es;
217         unsigned long def_mount_opts;
218
219         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
220
221         if (sbi->s_sb_block != 1)
222                 seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
223         if (test_opt(sb, MINIX_DF))
224                 seq_puts(seq, ",minixdf");
225         if (test_opt(sb, GRPID))
226                 seq_puts(seq, ",grpid");
227         if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
228                 seq_puts(seq, ",nogrpid");
229         if (sbi->s_resuid != EXT2_DEF_RESUID ||
230             le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
231                 seq_printf(seq, ",resuid=%u", sbi->s_resuid);
232         }
233         if (sbi->s_resgid != EXT2_DEF_RESGID ||
234             le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
235                 seq_printf(seq, ",resgid=%u", sbi->s_resgid);
236         }
237         if (test_opt(sb, ERRORS_CONT)) {
238                 int def_errors = le16_to_cpu(es->s_errors);
239
240                 if (def_errors == EXT2_ERRORS_PANIC ||
241                     def_errors == EXT2_ERRORS_RO) {
242                         seq_puts(seq, ",errors=continue");
243                 }
244         }
245         if (test_opt(sb, ERRORS_RO))
246                 seq_puts(seq, ",errors=remount-ro");
247         if (test_opt(sb, ERRORS_PANIC))
248                 seq_puts(seq, ",errors=panic");
249         if (test_opt(sb, NO_UID32))
250                 seq_puts(seq, ",nouid32");
251         if (test_opt(sb, DEBUG))
252                 seq_puts(seq, ",debug");
253         if (test_opt(sb, OLDALLOC))
254                 seq_puts(seq, ",oldalloc");
255
256 #ifdef CONFIG_EXT2_FS_XATTR
257         if (test_opt(sb, XATTR_USER))
258                 seq_puts(seq, ",user_xattr");
259         if (!test_opt(sb, XATTR_USER) &&
260             (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
261                 seq_puts(seq, ",nouser_xattr");
262         }
263 #endif
264
265 #ifdef CONFIG_EXT2_FS_POSIX_ACL
266         if (test_opt(sb, POSIX_ACL))
267                 seq_puts(seq, ",acl");
268         if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
269                 seq_puts(seq, ",noacl");
270 #endif
271
272         if (test_opt(sb, NOBH))
273                 seq_puts(seq, ",nobh");
274
275 #if defined(CONFIG_QUOTA)
276         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
277                 seq_puts(seq, ",usrquota");
278
279         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
280                 seq_puts(seq, ",grpquota");
281 #endif
282
283 #if defined(CONFIG_EXT2_FS_XIP)
284         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
285                 seq_puts(seq, ",xip");
286 #endif
287
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         .read_inode     = ext2_read_inode,
300         .write_inode    = ext2_write_inode,
301         .delete_inode   = ext2_delete_inode,
302         .put_super      = ext2_put_super,
303         .write_super    = ext2_write_super,
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 = iget(sb, ino);
330         if (inode == NULL)
331                 return ERR_PTR(-ENOMEM);
332         if (is_bad_inode(inode) ||
333             (generation && inode->i_generation != generation)) {
334                 /* we didn't find the right inode.. */
335                 iput(inode);
336                 return ERR_PTR(-ESTALE);
337         }
338         return inode;
339 }
340
341 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
342                 int fh_len, int fh_type)
343 {
344         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
345                                     ext2_nfs_get_inode);
346 }
347
348 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
349                 int fh_len, int fh_type)
350 {
351         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
352                                     ext2_nfs_get_inode);
353 }
354
355 /* Yes, most of these are left as NULL!!
356  * A NULL value implies the default, which works with ext2-like file
357  * systems, but can be improved upon.
358  * Currently only get_parent is required.
359  */
360 static const struct export_operations ext2_export_ops = {
361         .fh_to_dentry = ext2_fh_to_dentry,
362         .fh_to_parent = ext2_fh_to_parent,
363         .get_parent = ext2_get_parent,
364 };
365
366 static unsigned long get_sb_block(void **data)
367 {
368         unsigned long   sb_block;
369         char            *options = (char *) *data;
370
371         if (!options || strncmp(options, "sb=", 3) != 0)
372                 return 1;       /* Default location */
373         options += 3;
374         sb_block = simple_strtoul(options, &options, 0);
375         if (*options && *options != ',') {
376                 printk("EXT2-fs: Invalid sb specification: %s\n",
377                        (char *) *data);
378                 return 1;
379         }
380         if (*options == ',')
381                 options++;
382         *data = (void *) options;
383         return sb_block;
384 }
385
386 enum {
387         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
388         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
389         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
390         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
391         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
392         Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
393 };
394
395 static match_table_t tokens = {
396         {Opt_bsd_df, "bsddf"},
397         {Opt_minix_df, "minixdf"},
398         {Opt_grpid, "grpid"},
399         {Opt_grpid, "bsdgroups"},
400         {Opt_nogrpid, "nogrpid"},
401         {Opt_nogrpid, "sysvgroups"},
402         {Opt_resgid, "resgid=%u"},
403         {Opt_resuid, "resuid=%u"},
404         {Opt_sb, "sb=%u"},
405         {Opt_err_cont, "errors=continue"},
406         {Opt_err_panic, "errors=panic"},
407         {Opt_err_ro, "errors=remount-ro"},
408         {Opt_nouid32, "nouid32"},
409         {Opt_nocheck, "check=none"},
410         {Opt_nocheck, "nocheck"},
411         {Opt_debug, "debug"},
412         {Opt_oldalloc, "oldalloc"},
413         {Opt_orlov, "orlov"},
414         {Opt_nobh, "nobh"},
415         {Opt_user_xattr, "user_xattr"},
416         {Opt_nouser_xattr, "nouser_xattr"},
417         {Opt_acl, "acl"},
418         {Opt_noacl, "noacl"},
419         {Opt_xip, "xip"},
420         {Opt_grpquota, "grpquota"},
421         {Opt_ignore, "noquota"},
422         {Opt_quota, "quota"},
423         {Opt_usrquota, "usrquota"},
424         {Opt_reservation, "reservation"},
425         {Opt_noreservation, "noreservation"},
426         {Opt_err, NULL}
427 };
428
429 static int parse_options (char * options,
430                           struct ext2_sb_info *sbi)
431 {
432         char * p;
433         substring_t args[MAX_OPT_ARGS];
434         int option;
435
436         if (!options)
437                 return 1;
438
439         while ((p = strsep (&options, ",")) != NULL) {
440                 int token;
441                 if (!*p)
442                         continue;
443
444                 token = match_token(p, tokens, args);
445                 switch (token) {
446                 case Opt_bsd_df:
447                         clear_opt (sbi->s_mount_opt, MINIX_DF);
448                         break;
449                 case Opt_minix_df:
450                         set_opt (sbi->s_mount_opt, MINIX_DF);
451                         break;
452                 case Opt_grpid:
453                         set_opt (sbi->s_mount_opt, GRPID);
454                         break;
455                 case Opt_nogrpid:
456                         clear_opt (sbi->s_mount_opt, GRPID);
457                         break;
458                 case Opt_resuid:
459                         if (match_int(&args[0], &option))
460                                 return 0;
461                         sbi->s_resuid = option;
462                         break;
463                 case Opt_resgid:
464                         if (match_int(&args[0], &option))
465                                 return 0;
466                         sbi->s_resgid = option;
467                         break;
468                 case Opt_sb:
469                         /* handled by get_sb_block() instead of here */
470                         /* *sb_block = match_int(&args[0]); */
471                         break;
472                 case Opt_err_panic:
473                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
474                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
475                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
476                         break;
477                 case Opt_err_ro:
478                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
479                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
480                         set_opt (sbi->s_mount_opt, ERRORS_RO);
481                         break;
482                 case Opt_err_cont:
483                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
484                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
485                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
486                         break;
487                 case Opt_nouid32:
488                         set_opt (sbi->s_mount_opt, NO_UID32);
489                         break;
490                 case Opt_nocheck:
491                         clear_opt (sbi->s_mount_opt, CHECK);
492                         break;
493                 case Opt_debug:
494                         set_opt (sbi->s_mount_opt, DEBUG);
495                         break;
496                 case Opt_oldalloc:
497                         set_opt (sbi->s_mount_opt, OLDALLOC);
498                         break;
499                 case Opt_orlov:
500                         clear_opt (sbi->s_mount_opt, OLDALLOC);
501                         break;
502                 case Opt_nobh:
503                         set_opt (sbi->s_mount_opt, NOBH);
504                         break;
505 #ifdef CONFIG_EXT2_FS_XATTR
506                 case Opt_user_xattr:
507                         set_opt (sbi->s_mount_opt, XATTR_USER);
508                         break;
509                 case Opt_nouser_xattr:
510                         clear_opt (sbi->s_mount_opt, XATTR_USER);
511                         break;
512 #else
513                 case Opt_user_xattr:
514                 case Opt_nouser_xattr:
515                         printk("EXT2 (no)user_xattr options not supported\n");
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                         printk("EXT2 (no)acl options not supported\n");
529                         break;
530 #endif
531                 case Opt_xip:
532 #ifdef CONFIG_EXT2_FS_XIP
533                         set_opt (sbi->s_mount_opt, XIP);
534 #else
535                         printk("EXT2 xip option not supported\n");
536 #endif
537                         break;
538
539 #if defined(CONFIG_QUOTA)
540                 case Opt_quota:
541                 case Opt_usrquota:
542                         set_opt(sbi->s_mount_opt, USRQUOTA);
543                         break;
544
545                 case Opt_grpquota:
546                         set_opt(sbi->s_mount_opt, GRPQUOTA);
547                         break;
548 #else
549                 case Opt_quota:
550                 case Opt_usrquota:
551                 case Opt_grpquota:
552                         printk(KERN_ERR
553                                 "EXT2-fs: quota operations not supported.\n");
554
555                         break;
556 #endif
557
558                 case Opt_reservation:
559                         set_opt(sbi->s_mount_opt, RESERVATION);
560                         printk("reservations ON\n");
561                         break;
562                 case Opt_noreservation:
563                         clear_opt(sbi->s_mount_opt, RESERVATION);
564                         printk("reservations OFF\n");
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                 printk ("EXT2-fs warning: revision level too high, "
584                         "forcing read-only mode\n");
585                 res = MS_RDONLY;
586         }
587         if (read_only)
588                 return res;
589         if (!(sbi->s_mount_state & EXT2_VALID_FS))
590                 printk ("EXT2-fs warning: mounting unchecked fs, "
591                         "running e2fsck is recommended\n");
592         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
593                 printk ("EXT2-fs warning: mounting fs with errors, "
594                         "running e2fsck is recommended\n");
595         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
596                  le16_to_cpu(es->s_mnt_count) >=
597                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
598                 printk ("EXT2-fs warning: maximal mount count reached, "
599                         "running e2fsck is recommended\n");
600         else if (le32_to_cpu(es->s_checkinterval) &&
601                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
602                 printk ("EXT2-fs warning: checktime reached, "
603                         "running e2fsck is recommended\n");
604         if (!le16_to_cpu(es->s_max_mnt_count))
605                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
606         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
607         ext2_write_super(sb);
608         if (test_opt (sb, DEBUG))
609                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
610                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
611                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
612                         sbi->s_frag_size,
613                         sbi->s_groups_count,
614                         EXT2_BLOCKS_PER_GROUP(sb),
615                         EXT2_INODES_PER_GROUP(sb),
616                         sbi->s_mount_opt);
617         return res;
618 }
619
620 static int ext2_check_descriptors (struct super_block * sb)
621 {
622         int i;
623         int desc_block = 0;
624         struct ext2_sb_info *sbi = EXT2_SB(sb);
625         unsigned long first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
626         unsigned long last_block;
627         struct ext2_group_desc * gdp = NULL;
628
629         ext2_debug ("Checking group descriptors");
630
631         for (i = 0; i < sbi->s_groups_count; i++)
632         {
633                 if (i == sbi->s_groups_count - 1)
634                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
635                 else
636                         last_block = first_block +
637                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
638
639                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
640                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
641                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
642                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
643                 {
644                         ext2_error (sb, "ext2_check_descriptors",
645                                     "Block bitmap for group %d"
646                                     " not in group (block %lu)!",
647                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
648                         return 0;
649                 }
650                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
651                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
652                 {
653                         ext2_error (sb, "ext2_check_descriptors",
654                                     "Inode bitmap for group %d"
655                                     " not in group (block %lu)!",
656                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
657                         return 0;
658                 }
659                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
660                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
661                     last_block)
662                 {
663                         ext2_error (sb, "ext2_check_descriptors",
664                                     "Inode table for group %d"
665                                     " not in group (block %lu)!",
666                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
667                         return 0;
668                 }
669                 first_block += EXT2_BLOCKS_PER_GROUP(sb);
670                 gdp++;
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         /* This constant is calculated to be the largest file size for a
684          * dense, 4k-blocksize file such that the total number of
685          * sectors in the file, including data and all indirect blocks,
686          * does not exceed 2^32. */
687         const loff_t upper_limit = 0x1ff7fffd000LL;
688
689         res += 1LL << (bits-2);
690         res += 1LL << (2*(bits-2));
691         res += 1LL << (3*(bits-2));
692         res <<= bits;
693         if (res > upper_limit)
694                 res = upper_limit;
695         return res;
696 }
697
698 static unsigned long descriptor_loc(struct super_block *sb,
699                                     unsigned long logic_sb_block,
700                                     int nr)
701 {
702         struct ext2_sb_info *sbi = EXT2_SB(sb);
703         unsigned long bg, first_data_block, first_meta_bg;
704         int has_super = 0;
705         
706         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
707         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
708
709         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
710             nr < first_meta_bg)
711                 return (logic_sb_block + nr + 1);
712         bg = sbi->s_desc_per_block * nr;
713         if (ext2_bg_has_super(sb, bg))
714                 has_super = 1;
715         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
716 }
717
718 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
719 {
720         struct buffer_head * bh;
721         struct ext2_sb_info * sbi;
722         struct ext2_super_block * es;
723         struct inode *root;
724         unsigned long block;
725         unsigned long sb_block = get_sb_block(&data);
726         unsigned long logic_sb_block;
727         unsigned long offset = 0;
728         unsigned long def_mount_opts;
729         int blocksize = BLOCK_SIZE;
730         int db_count;
731         int i, j;
732         __le32 features;
733         int err;
734
735         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
736         if (!sbi)
737                 return -ENOMEM;
738         sb->s_fs_info = sbi;
739         sbi->s_sb_block = sb_block;
740
741         /*
742          * See what the current blocksize for the device is, and
743          * use that as the blocksize.  Otherwise (or if the blocksize
744          * is smaller than the default) use the default.
745          * This is important for devices that have a hardware
746          * sectorsize that is larger than the default.
747          */
748         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
749         if (!blocksize) {
750                 printk ("EXT2-fs: unable to set blocksize\n");
751                 goto failed_sbi;
752         }
753
754         /*
755          * If the superblock doesn't start on a hardware sector boundary,
756          * calculate the offset.  
757          */
758         if (blocksize != BLOCK_SIZE) {
759                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
760                 offset = (sb_block*BLOCK_SIZE) % blocksize;
761         } else {
762                 logic_sb_block = sb_block;
763         }
764
765         if (!(bh = sb_bread(sb, logic_sb_block))) {
766                 printk ("EXT2-fs: unable to read superblock\n");
767                 goto failed_sbi;
768         }
769         /*
770          * Note: s_es must be initialized as soon as possible because
771          *       some ext2 macro-instructions depend on its value
772          */
773         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
774         sbi->s_es = es;
775         sb->s_magic = le16_to_cpu(es->s_magic);
776
777         if (sb->s_magic != EXT2_SUPER_MAGIC)
778                 goto cantfind_ext2;
779
780         /* Set defaults before we parse the mount options */
781         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
782         if (def_mount_opts & EXT2_DEFM_DEBUG)
783                 set_opt(sbi->s_mount_opt, DEBUG);
784         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
785                 set_opt(sbi->s_mount_opt, GRPID);
786         if (def_mount_opts & EXT2_DEFM_UID16)
787                 set_opt(sbi->s_mount_opt, NO_UID32);
788 #ifdef CONFIG_EXT2_FS_XATTR
789         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
790                 set_opt(sbi->s_mount_opt, XATTR_USER);
791 #endif
792 #ifdef CONFIG_EXT2_FS_POSIX_ACL
793         if (def_mount_opts & EXT2_DEFM_ACL)
794                 set_opt(sbi->s_mount_opt, POSIX_ACL);
795 #endif
796         
797         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
798                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
799         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
800                 set_opt(sbi->s_mount_opt, ERRORS_RO);
801         else
802                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
803
804         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
805         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
806         
807         set_opt(sbi->s_mount_opt, RESERVATION);
808
809         if (!parse_options ((char *) data, sbi))
810                 goto failed_mount;
811
812         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
813                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
814                  MS_POSIXACL : 0);
815
816         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
817                                     EXT2_MOUNT_XIP if not */
818
819         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
820             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
821              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
822              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
823                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
824                        "running e2fsck is recommended\n");
825         /*
826          * Check feature flags regardless of the revision level, since we
827          * previously didn't change the revision level when setting the flags,
828          * so there is a chance incompat flags are set on a rev 0 filesystem.
829          */
830         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
831         if (features) {
832                 printk("EXT2-fs: %s: couldn't mount because of "
833                        "unsupported optional features (%x).\n",
834                        sb->s_id, le32_to_cpu(features));
835                 goto failed_mount;
836         }
837         if (!(sb->s_flags & MS_RDONLY) &&
838             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
839                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
840                        "unsupported optional features (%x).\n",
841                        sb->s_id, le32_to_cpu(features));
842                 goto failed_mount;
843         }
844
845         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
846
847         if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
848                                   (sb->s_blocksize != blocksize))) {
849                 if (!silent)
850                         printk("XIP: Unsupported blocksize\n");
851                 goto failed_mount;
852         }
853
854         /* If the blocksize doesn't match, re-read the thing.. */
855         if (sb->s_blocksize != blocksize) {
856                 brelse(bh);
857
858                 if (!sb_set_blocksize(sb, blocksize)) {
859                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
860                         goto failed_sbi;
861                 }
862
863                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
864                 offset = (sb_block*BLOCK_SIZE) % blocksize;
865                 bh = sb_bread(sb, logic_sb_block);
866                 if(!bh) {
867                         printk("EXT2-fs: Couldn't read superblock on "
868                                "2nd try.\n");
869                         goto failed_sbi;
870                 }
871                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
872                 sbi->s_es = es;
873                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
874                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
875                         goto failed_mount;
876                 }
877         }
878
879         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
880
881         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
882                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
883                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
884         } else {
885                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
886                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
887                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
888                     !is_power_of_2(sbi->s_inode_size) ||
889                     (sbi->s_inode_size > blocksize)) {
890                         printk ("EXT2-fs: unsupported inode size: %d\n",
891                                 sbi->s_inode_size);
892                         goto failed_mount;
893                 }
894         }
895
896         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
897                                    le32_to_cpu(es->s_log_frag_size);
898         if (sbi->s_frag_size == 0)
899                 goto cantfind_ext2;
900         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
901
902         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
903         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
904         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
905
906         if (EXT2_INODE_SIZE(sb) == 0)
907                 goto cantfind_ext2;
908         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
909         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
910                 goto cantfind_ext2;
911         sbi->s_itb_per_group = sbi->s_inodes_per_group /
912                                         sbi->s_inodes_per_block;
913         sbi->s_desc_per_block = sb->s_blocksize /
914                                         sizeof (struct ext2_group_desc);
915         sbi->s_sbh = bh;
916         sbi->s_mount_state = le16_to_cpu(es->s_state);
917         sbi->s_addr_per_block_bits =
918                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
919         sbi->s_desc_per_block_bits =
920                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
921
922         if (sb->s_magic != EXT2_SUPER_MAGIC)
923                 goto cantfind_ext2;
924
925         if (sb->s_blocksize != bh->b_size) {
926                 if (!silent)
927                         printk ("VFS: Unsupported blocksize on dev "
928                                 "%s.\n", sb->s_id);
929                 goto failed_mount;
930         }
931
932         if (sb->s_blocksize != sbi->s_frag_size) {
933                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
934                         sbi->s_frag_size, sb->s_blocksize);
935                 goto failed_mount;
936         }
937
938         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
939                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
940                         sbi->s_blocks_per_group);
941                 goto failed_mount;
942         }
943         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
944                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
945                         sbi->s_frags_per_group);
946                 goto failed_mount;
947         }
948         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
949                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
950                         sbi->s_inodes_per_group);
951                 goto failed_mount;
952         }
953
954         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
955                 goto cantfind_ext2;
956         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
957                                 le32_to_cpu(es->s_first_data_block) - 1)
958                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
959         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
960                    EXT2_DESC_PER_BLOCK(sb);
961         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
962         if (sbi->s_group_desc == NULL) {
963                 printk ("EXT2-fs: not enough memory\n");
964                 goto failed_mount;
965         }
966         bgl_lock_init(&sbi->s_blockgroup_lock);
967         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
968         if (!sbi->s_debts) {
969                 printk ("EXT2-fs: not enough memory\n");
970                 goto failed_mount_group_desc;
971         }
972         for (i = 0; i < db_count; i++) {
973                 block = descriptor_loc(sb, logic_sb_block, i);
974                 sbi->s_group_desc[i] = sb_bread(sb, block);
975                 if (!sbi->s_group_desc[i]) {
976                         for (j = 0; j < i; j++)
977                                 brelse (sbi->s_group_desc[j]);
978                         printk ("EXT2-fs: unable to read group descriptors\n");
979                         goto failed_mount_group_desc;
980                 }
981         }
982         if (!ext2_check_descriptors (sb)) {
983                 printk ("EXT2-fs: group descriptors corrupted!\n");
984                 goto failed_mount2;
985         }
986         sbi->s_gdb_count = db_count;
987         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
988         spin_lock_init(&sbi->s_next_gen_lock);
989
990         /* per fileystem reservation list head & lock */
991         spin_lock_init(&sbi->s_rsv_window_lock);
992         sbi->s_rsv_window_root = RB_ROOT;
993         /*
994          * Add a single, static dummy reservation to the start of the
995          * reservation window list --- it gives us a placeholder for
996          * append-at-start-of-list which makes the allocation logic
997          * _much_ simpler.
998          */
999         sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1000         sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1001         sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1002         sbi->s_rsv_window_head.rsv_goal_size = 0;
1003         ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1004
1005         err = percpu_counter_init(&sbi->s_freeblocks_counter,
1006                                 ext2_count_free_blocks(sb));
1007         if (!err) {
1008                 err = percpu_counter_init(&sbi->s_freeinodes_counter,
1009                                 ext2_count_free_inodes(sb));
1010         }
1011         if (!err) {
1012                 err = percpu_counter_init(&sbi->s_dirs_counter,
1013                                 ext2_count_dirs(sb));
1014         }
1015         if (err) {
1016                 printk(KERN_ERR "EXT2-fs: insufficient memory\n");
1017                 goto failed_mount3;
1018         }
1019         /*
1020          * set up enough so that it can read an inode
1021          */
1022         sb->s_op = &ext2_sops;
1023         sb->s_export_op = &ext2_export_ops;
1024         sb->s_xattr = ext2_xattr_handlers;
1025         root = iget(sb, EXT2_ROOT_INO);
1026         sb->s_root = d_alloc_root(root);
1027         if (!sb->s_root) {
1028                 iput(root);
1029                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
1030                 goto failed_mount3;
1031         }
1032         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1033                 dput(sb->s_root);
1034                 sb->s_root = NULL;
1035                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
1036                 goto failed_mount3;
1037         }
1038         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1039                 ext2_warning(sb, __FUNCTION__,
1040                         "mounting ext3 filesystem as ext2");
1041         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
1042         return 0;
1043
1044 cantfind_ext2:
1045         if (!silent)
1046                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
1047                        sb->s_id);
1048         goto failed_mount;
1049 failed_mount3:
1050         percpu_counter_destroy(&sbi->s_freeblocks_counter);
1051         percpu_counter_destroy(&sbi->s_freeinodes_counter);
1052         percpu_counter_destroy(&sbi->s_dirs_counter);
1053 failed_mount2:
1054         for (i = 0; i < db_count; i++)
1055                 brelse(sbi->s_group_desc[i]);
1056 failed_mount_group_desc:
1057         kfree(sbi->s_group_desc);
1058         kfree(sbi->s_debts);
1059 failed_mount:
1060         brelse(bh);
1061 failed_sbi:
1062         sb->s_fs_info = NULL;
1063         kfree(sbi);
1064         return -EINVAL;
1065 }
1066
1067 static void ext2_commit_super (struct super_block * sb,
1068                                struct ext2_super_block * es)
1069 {
1070         es->s_wtime = cpu_to_le32(get_seconds());
1071         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1072         sb->s_dirt = 0;
1073 }
1074
1075 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
1076 {
1077         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1078         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1079         es->s_wtime = cpu_to_le32(get_seconds());
1080         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1081         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1082         sb->s_dirt = 0;
1083 }
1084
1085 /*
1086  * In the second extended file system, it is not necessary to
1087  * write the super block since we use a mapping of the
1088  * disk super block in a buffer.
1089  *
1090  * However, this function is still used to set the fs valid
1091  * flags to 0.  We need to set this flag to 0 since the fs
1092  * may have been checked while mounted and e2fsck may have
1093  * set s_state to EXT2_VALID_FS after some corrections.
1094  */
1095
1096 void ext2_write_super (struct super_block * sb)
1097 {
1098         struct ext2_super_block * es;
1099         lock_kernel();
1100         if (!(sb->s_flags & MS_RDONLY)) {
1101                 es = EXT2_SB(sb)->s_es;
1102
1103                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
1104                         ext2_debug ("setting valid to 0\n");
1105                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
1106                                                   ~EXT2_VALID_FS);
1107                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1108                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1109                         es->s_mtime = cpu_to_le32(get_seconds());
1110                         ext2_sync_super(sb, es);
1111                 } else
1112                         ext2_commit_super (sb, es);
1113         }
1114         sb->s_dirt = 0;
1115         unlock_kernel();
1116 }
1117
1118 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1119 {
1120         struct ext2_sb_info * sbi = EXT2_SB(sb);
1121         struct ext2_super_block * es;
1122         unsigned long old_mount_opt = sbi->s_mount_opt;
1123         struct ext2_mount_options old_opts;
1124         unsigned long old_sb_flags;
1125         int err;
1126
1127         /* Store the old options */
1128         old_sb_flags = sb->s_flags;
1129         old_opts.s_mount_opt = sbi->s_mount_opt;
1130         old_opts.s_resuid = sbi->s_resuid;
1131         old_opts.s_resgid = sbi->s_resgid;
1132
1133         /*
1134          * Allow the "check" option to be passed as a remount option.
1135          */
1136         if (!parse_options (data, sbi)) {
1137                 err = -EINVAL;
1138                 goto restore_opts;
1139         }
1140
1141         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1142                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1143
1144         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1145                                     EXT2_MOUNT_XIP if not */
1146
1147         if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1148                 printk("XIP: Unsupported blocksize\n");
1149                 err = -EINVAL;
1150                 goto restore_opts;
1151         }
1152
1153         es = sbi->s_es;
1154         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1155             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1156             invalidate_inodes(sb))
1157                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1158                              "xip remain in cache (no functional problem)");
1159         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1160                 return 0;
1161         if (*flags & MS_RDONLY) {
1162                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1163                     !(sbi->s_mount_state & EXT2_VALID_FS))
1164                         return 0;
1165                 /*
1166                  * OK, we are remounting a valid rw partition rdonly, so set
1167                  * the rdonly flag and then mark the partition as valid again.
1168                  */
1169                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1170                 es->s_mtime = cpu_to_le32(get_seconds());
1171         } else {
1172                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1173                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1174                 if (ret) {
1175                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1176                                "unsupported optional features (%x).\n",
1177                                sb->s_id, le32_to_cpu(ret));
1178                         err = -EROFS;
1179                         goto restore_opts;
1180                 }
1181                 /*
1182                  * Mounting a RDONLY partition read-write, so reread and
1183                  * store the current valid flag.  (It may have been changed
1184                  * by e2fsck since we originally mounted the partition.)
1185                  */
1186                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1187                 if (!ext2_setup_super (sb, es, 0))
1188                         sb->s_flags &= ~MS_RDONLY;
1189         }
1190         ext2_sync_super(sb, es);
1191         return 0;
1192 restore_opts:
1193         sbi->s_mount_opt = old_opts.s_mount_opt;
1194         sbi->s_resuid = old_opts.s_resuid;
1195         sbi->s_resgid = old_opts.s_resgid;
1196         sb->s_flags = old_sb_flags;
1197         return err;
1198 }
1199
1200 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1201 {
1202         struct super_block *sb = dentry->d_sb;
1203         struct ext2_sb_info *sbi = EXT2_SB(sb);
1204         struct ext2_super_block *es = sbi->s_es;
1205         u64 fsid;
1206
1207         if (test_opt (sb, MINIX_DF))
1208                 sbi->s_overhead_last = 0;
1209         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1210                 unsigned long i, overhead = 0;
1211                 smp_rmb();
1212
1213                 /*
1214                  * Compute the overhead (FS structures). This is constant
1215                  * for a given filesystem unless the number of block groups
1216                  * changes so we cache the previous value until it does.
1217                  */
1218
1219                 /*
1220                  * All of the blocks before first_data_block are
1221                  * overhead
1222                  */
1223                 overhead = le32_to_cpu(es->s_first_data_block);
1224
1225                 /*
1226                  * Add the overhead attributed to the superblock and
1227                  * block group descriptors.  If the sparse superblocks
1228                  * feature is turned on, then not all groups have this.
1229                  */
1230                 for (i = 0; i < sbi->s_groups_count; i++)
1231                         overhead += ext2_bg_has_super(sb, i) +
1232                                 ext2_bg_num_gdb(sb, i);
1233
1234                 /*
1235                  * Every block group has an inode bitmap, a block
1236                  * bitmap, and an inode table.
1237                  */
1238                 overhead += (sbi->s_groups_count *
1239                              (2 + sbi->s_itb_per_group));
1240                 sbi->s_overhead_last = overhead;
1241                 smp_wmb();
1242                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1243         }
1244
1245         buf->f_type = EXT2_SUPER_MAGIC;
1246         buf->f_bsize = sb->s_blocksize;
1247         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1248         buf->f_bfree = ext2_count_free_blocks(sb);
1249         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1250         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1251         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1252                 buf->f_bavail = 0;
1253         buf->f_files = le32_to_cpu(es->s_inodes_count);
1254         buf->f_ffree = ext2_count_free_inodes(sb);
1255         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1256         buf->f_namelen = EXT2_NAME_LEN;
1257         fsid = le64_to_cpup((void *)es->s_uuid) ^
1258                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1259         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1260         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1261         return 0;
1262 }
1263
1264 static int ext2_get_sb(struct file_system_type *fs_type,
1265         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1266 {
1267         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1268 }
1269
1270 #ifdef CONFIG_QUOTA
1271
1272 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1273  * acquiring the locks... As quota files are never truncated and quota code
1274  * itself serializes the operations (and noone else should touch the files)
1275  * we don't have to be afraid of races */
1276 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1277                                size_t len, loff_t off)
1278 {
1279         struct inode *inode = sb_dqopt(sb)->files[type];
1280         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1281         int err = 0;
1282         int offset = off & (sb->s_blocksize - 1);
1283         int tocopy;
1284         size_t toread;
1285         struct buffer_head tmp_bh;
1286         struct buffer_head *bh;
1287         loff_t i_size = i_size_read(inode);
1288
1289         if (off > i_size)
1290                 return 0;
1291         if (off+len > i_size)
1292                 len = i_size-off;
1293         toread = len;
1294         while (toread > 0) {
1295                 tocopy = sb->s_blocksize - offset < toread ?
1296                                 sb->s_blocksize - offset : toread;
1297
1298                 tmp_bh.b_state = 0;
1299                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1300                 if (err < 0)
1301                         return err;
1302                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1303                         memset(data, 0, tocopy);
1304                 else {
1305                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1306                         if (!bh)
1307                                 return -EIO;
1308                         memcpy(data, bh->b_data+offset, tocopy);
1309                         brelse(bh);
1310                 }
1311                 offset = 0;
1312                 toread -= tocopy;
1313                 data += tocopy;
1314                 blk++;
1315         }
1316         return len;
1317 }
1318
1319 /* Write to quotafile */
1320 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1321                                 const char *data, size_t len, loff_t off)
1322 {
1323         struct inode *inode = sb_dqopt(sb)->files[type];
1324         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1325         int err = 0;
1326         int offset = off & (sb->s_blocksize - 1);
1327         int tocopy;
1328         size_t towrite = len;
1329         struct buffer_head tmp_bh;
1330         struct buffer_head *bh;
1331
1332         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1333         while (towrite > 0) {
1334                 tocopy = sb->s_blocksize - offset < towrite ?
1335                                 sb->s_blocksize - offset : towrite;
1336
1337                 tmp_bh.b_state = 0;
1338                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1339                 if (err < 0)
1340                         goto out;
1341                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1342                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1343                 else
1344                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1345                 if (!bh) {
1346                         err = -EIO;
1347                         goto out;
1348                 }
1349                 lock_buffer(bh);
1350                 memcpy(bh->b_data+offset, data, tocopy);
1351                 flush_dcache_page(bh->b_page);
1352                 set_buffer_uptodate(bh);
1353                 mark_buffer_dirty(bh);
1354                 unlock_buffer(bh);
1355                 brelse(bh);
1356                 offset = 0;
1357                 towrite -= tocopy;
1358                 data += tocopy;
1359                 blk++;
1360         }
1361 out:
1362         if (len == towrite)
1363                 return err;
1364         if (inode->i_size < off+len-towrite)
1365                 i_size_write(inode, off+len-towrite);
1366         inode->i_version++;
1367         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1368         mark_inode_dirty(inode);
1369         mutex_unlock(&inode->i_mutex);
1370         return len - towrite;
1371 }
1372
1373 #endif
1374
1375 static struct file_system_type ext2_fs_type = {
1376         .owner          = THIS_MODULE,
1377         .name           = "ext2",
1378         .get_sb         = ext2_get_sb,
1379         .kill_sb        = kill_block_super,
1380         .fs_flags       = FS_REQUIRES_DEV,
1381 };
1382
1383 static int __init init_ext2_fs(void)
1384 {
1385         int err = init_ext2_xattr();
1386         if (err)
1387                 return err;
1388         err = init_inodecache();
1389         if (err)
1390                 goto out1;
1391         err = register_filesystem(&ext2_fs_type);
1392         if (err)
1393                 goto out;
1394         return 0;
1395 out:
1396         destroy_inodecache();
1397 out1:
1398         exit_ext2_xattr();
1399         return err;
1400 }
1401
1402 static void __exit exit_ext2_fs(void)
1403 {
1404         unregister_filesystem(&ext2_fs_type);
1405         destroy_inodecache();
1406         exit_ext2_xattr();
1407 }
1408
1409 module_init(init_ext2_fs)
1410 module_exit(exit_ext2_fs)