ext2: convert byte order of constant instead of variable
[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 |= cpu_to_le16(EXT2_ERROR_FS);
55                 ext2_sync_super(sb, es);
56         }
57
58         va_start(args, fmt);
59         printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
60         vprintk(fmt, args);
61         printk("\n");
62         va_end(args);
63
64         if (test_opt(sb, ERRORS_PANIC))
65                 panic("EXT2-fs panic from previous error\n");
66         if (test_opt(sb, ERRORS_RO)) {
67                 printk("Remounting filesystem read-only\n");
68                 sb->s_flags |= MS_RDONLY;
69         }
70 }
71
72 void ext2_warning (struct super_block * sb, const char * function,
73                    const char * fmt, ...)
74 {
75         va_list args;
76
77         va_start(args, fmt);
78         printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
79                sb->s_id, function);
80         vprintk(fmt, args);
81         printk("\n");
82         va_end(args);
83 }
84
85 void ext2_update_dynamic_rev(struct super_block *sb)
86 {
87         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
88
89         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
90                 return;
91
92         ext2_warning(sb, __FUNCTION__,
93                      "updating to rev %d because of new feature flag, "
94                      "running e2fsck is recommended",
95                      EXT2_DYNAMIC_REV);
96
97         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
98         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
99         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
100         /* leave es->s_feature_*compat flags alone */
101         /* es->s_uuid will be set by e2fsck if empty */
102
103         /*
104          * The rest of the superblock fields should be zero, and if not it
105          * means they are likely already in use, so leave them alone.  We
106          * can leave it up to e2fsck to clean up any inconsistencies there.
107          */
108 }
109
110 static void ext2_put_super (struct super_block * sb)
111 {
112         int db_count;
113         int i;
114         struct ext2_sb_info *sbi = EXT2_SB(sb);
115
116         ext2_xattr_put_super(sb);
117         if (!(sb->s_flags & MS_RDONLY)) {
118                 struct ext2_super_block *es = sbi->s_es;
119
120                 es->s_state = cpu_to_le16(sbi->s_mount_state);
121                 ext2_sync_super(sb, es);
122         }
123         db_count = sbi->s_gdb_count;
124         for (i = 0; i < db_count; i++)
125                 if (sbi->s_group_desc[i])
126                         brelse (sbi->s_group_desc[i]);
127         kfree(sbi->s_group_desc);
128         kfree(sbi->s_debts);
129         percpu_counter_destroy(&sbi->s_freeblocks_counter);
130         percpu_counter_destroy(&sbi->s_freeinodes_counter);
131         percpu_counter_destroy(&sbi->s_dirs_counter);
132         brelse (sbi->s_sbh);
133         sb->s_fs_info = NULL;
134         kfree(sbi);
135
136         return;
137 }
138
139 static struct kmem_cache * ext2_inode_cachep;
140
141 static struct inode *ext2_alloc_inode(struct super_block *sb)
142 {
143         struct ext2_inode_info *ei;
144         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
145         if (!ei)
146                 return NULL;
147 #ifdef CONFIG_EXT2_FS_POSIX_ACL
148         ei->i_acl = EXT2_ACL_NOT_CACHED;
149         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
150 #endif
151         ei->i_block_alloc_info = NULL;
152         ei->vfs_inode.i_version = 1;
153         return &ei->vfs_inode;
154 }
155
156 static void ext2_destroy_inode(struct inode *inode)
157 {
158         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
159 }
160
161 static void init_once(struct kmem_cache * cachep, void *foo)
162 {
163         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
164
165         rwlock_init(&ei->i_meta_lock);
166 #ifdef CONFIG_EXT2_FS_XATTR
167         init_rwsem(&ei->xattr_sem);
168 #endif
169         mutex_init(&ei->truncate_mutex);
170         inode_init_once(&ei->vfs_inode);
171 }
172
173 static int init_inodecache(void)
174 {
175         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
176                                              sizeof(struct ext2_inode_info),
177                                              0, (SLAB_RECLAIM_ACCOUNT|
178                                                 SLAB_MEM_SPREAD),
179                                              init_once);
180         if (ext2_inode_cachep == NULL)
181                 return -ENOMEM;
182         return 0;
183 }
184
185 static void destroy_inodecache(void)
186 {
187         kmem_cache_destroy(ext2_inode_cachep);
188 }
189
190 static void ext2_clear_inode(struct inode *inode)
191 {
192         struct ext2_block_alloc_info *rsv = EXT2_I(inode)->i_block_alloc_info;
193 #ifdef CONFIG_EXT2_FS_POSIX_ACL
194         struct ext2_inode_info *ei = EXT2_I(inode);
195
196         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
197                 posix_acl_release(ei->i_acl);
198                 ei->i_acl = EXT2_ACL_NOT_CACHED;
199         }
200         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
201                 posix_acl_release(ei->i_default_acl);
202                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
203         }
204 #endif
205         ext2_discard_reservation(inode);
206         EXT2_I(inode)->i_block_alloc_info = NULL;
207         if (unlikely(rsv))
208                 kfree(rsv);
209 }
210
211 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
212 {
213         struct super_block *sb = vfs->mnt_sb;
214         struct ext2_sb_info *sbi = EXT2_SB(sb);
215         struct ext2_super_block *es = sbi->s_es;
216         unsigned long def_mount_opts;
217
218         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
219
220         if (sbi->s_sb_block != 1)
221                 seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
222         if (test_opt(sb, MINIX_DF))
223                 seq_puts(seq, ",minixdf");
224         if (test_opt(sb, GRPID))
225                 seq_puts(seq, ",grpid");
226         if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
227                 seq_puts(seq, ",nogrpid");
228         if (sbi->s_resuid != EXT2_DEF_RESUID ||
229             le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
230                 seq_printf(seq, ",resuid=%u", sbi->s_resuid);
231         }
232         if (sbi->s_resgid != EXT2_DEF_RESGID ||
233             le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
234                 seq_printf(seq, ",resgid=%u", sbi->s_resgid);
235         }
236         if (test_opt(sb, ERRORS_RO)) {
237                 int def_errors = le16_to_cpu(es->s_errors);
238
239                 if (def_errors == EXT2_ERRORS_PANIC ||
240                     def_errors == EXT2_ERRORS_CONTINUE) {
241                         seq_puts(seq, ",errors=remount-ro");
242                 }
243         }
244         if (test_opt(sb, ERRORS_CONT))
245                 seq_puts(seq, ",errors=continue");
246         if (test_opt(sb, ERRORS_PANIC))
247                 seq_puts(seq, ",errors=panic");
248         if (test_opt(sb, NO_UID32))
249                 seq_puts(seq, ",nouid32");
250         if (test_opt(sb, DEBUG))
251                 seq_puts(seq, ",debug");
252         if (test_opt(sb, OLDALLOC))
253                 seq_puts(seq, ",oldalloc");
254
255 #ifdef CONFIG_EXT2_FS_XATTR
256         if (test_opt(sb, XATTR_USER))
257                 seq_puts(seq, ",user_xattr");
258         if (!test_opt(sb, XATTR_USER) &&
259             (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
260                 seq_puts(seq, ",nouser_xattr");
261         }
262 #endif
263
264 #ifdef CONFIG_EXT2_FS_POSIX_ACL
265         if (test_opt(sb, POSIX_ACL))
266                 seq_puts(seq, ",acl");
267         if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
268                 seq_puts(seq, ",noacl");
269 #endif
270
271         if (test_opt(sb, NOBH))
272                 seq_puts(seq, ",nobh");
273
274 #if defined(CONFIG_QUOTA)
275         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
276                 seq_puts(seq, ",usrquota");
277
278         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
279                 seq_puts(seq, ",grpquota");
280 #endif
281
282 #if defined(CONFIG_EXT2_FS_XIP)
283         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
284                 seq_puts(seq, ",xip");
285 #endif
286
287         if (!test_opt(sb, RESERVATION))
288                 seq_puts(seq, ",noreservation");
289
290         return 0;
291 }
292
293 #ifdef CONFIG_QUOTA
294 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
295 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
296 #endif
297
298 static const struct super_operations ext2_sops = {
299         .alloc_inode    = ext2_alloc_inode,
300         .destroy_inode  = ext2_destroy_inode,
301         .write_inode    = ext2_write_inode,
302         .delete_inode   = ext2_delete_inode,
303         .put_super      = ext2_put_super,
304         .write_super    = ext2_write_super,
305         .statfs         = ext2_statfs,
306         .remount_fs     = ext2_remount,
307         .clear_inode    = ext2_clear_inode,
308         .show_options   = ext2_show_options,
309 #ifdef CONFIG_QUOTA
310         .quota_read     = ext2_quota_read,
311         .quota_write    = ext2_quota_write,
312 #endif
313 };
314
315 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
316                 u64 ino, u32 generation)
317 {
318         struct inode *inode;
319
320         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
321                 return ERR_PTR(-ESTALE);
322         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
323                 return ERR_PTR(-ESTALE);
324
325         /* iget isn't really right if the inode is currently unallocated!!
326          * ext2_read_inode currently does appropriate checks, but
327          * it might be "neater" to call ext2_get_inode first and check
328          * if the inode is valid.....
329          */
330         inode = ext2_iget(sb, ino);
331         if (IS_ERR(inode))
332                 return ERR_CAST(inode);
333         if (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         le16_add_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         struct ext2_sb_info *sbi = EXT2_SB(sb);
624         unsigned long first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
625         unsigned long last_block;
626
627         ext2_debug ("Checking group descriptors");
628
629         for (i = 0; i < sbi->s_groups_count; i++) {
630                 struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
631
632                 if (i == sbi->s_groups_count - 1)
633                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
634                 else
635                         last_block = first_block +
636                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
637
638                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
639                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
640                 {
641                         ext2_error (sb, "ext2_check_descriptors",
642                                     "Block bitmap for group %d"
643                                     " not in group (block %lu)!",
644                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
645                         return 0;
646                 }
647                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
648                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
649                 {
650                         ext2_error (sb, "ext2_check_descriptors",
651                                     "Inode bitmap for group %d"
652                                     " not in group (block %lu)!",
653                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
654                         return 0;
655                 }
656                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
657                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
658                     last_block)
659                 {
660                         ext2_error (sb, "ext2_check_descriptors",
661                                     "Inode table for group %d"
662                                     " not in group (block %lu)!",
663                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
664                         return 0;
665                 }
666                 first_block += EXT2_BLOCKS_PER_GROUP(sb);
667         }
668         return 1;
669 }
670
671 /*
672  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
673  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
674  * We need to be 1 filesystem block less than the 2^32 sector limit.
675  */
676 static loff_t ext2_max_size(int bits)
677 {
678         loff_t res = EXT2_NDIR_BLOCKS;
679         int meta_blocks;
680         loff_t upper_limit;
681
682         /* This is calculated to be the largest file size for a
683          * dense, file such that the total number of
684          * sectors in the file, including data and all indirect blocks,
685          * does not exceed 2^32 -1
686          * __u32 i_blocks representing the total number of
687          * 512 bytes blocks of the file
688          */
689         upper_limit = (1LL << 32) - 1;
690
691         /* total blocks in file system block size */
692         upper_limit >>= (bits - 9);
693
694
695         /* indirect blocks */
696         meta_blocks = 1;
697         /* double indirect blocks */
698         meta_blocks += 1 + (1LL << (bits-2));
699         /* tripple indirect blocks */
700         meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
701
702         upper_limit -= meta_blocks;
703         upper_limit <<= bits;
704
705         res += 1LL << (bits-2);
706         res += 1LL << (2*(bits-2));
707         res += 1LL << (3*(bits-2));
708         res <<= bits;
709         if (res > upper_limit)
710                 res = upper_limit;
711
712         if (res > MAX_LFS_FILESIZE)
713                 res = MAX_LFS_FILESIZE;
714
715         return res;
716 }
717
718 static unsigned long descriptor_loc(struct super_block *sb,
719                                     unsigned long logic_sb_block,
720                                     int nr)
721 {
722         struct ext2_sb_info *sbi = EXT2_SB(sb);
723         unsigned long bg, first_data_block, first_meta_bg;
724         int has_super = 0;
725         
726         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
727         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
728
729         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
730             nr < first_meta_bg)
731                 return (logic_sb_block + nr + 1);
732         bg = sbi->s_desc_per_block * nr;
733         if (ext2_bg_has_super(sb, bg))
734                 has_super = 1;
735         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
736 }
737
738 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
739 {
740         struct buffer_head * bh;
741         struct ext2_sb_info * sbi;
742         struct ext2_super_block * es;
743         struct inode *root;
744         unsigned long block;
745         unsigned long sb_block = get_sb_block(&data);
746         unsigned long logic_sb_block;
747         unsigned long offset = 0;
748         unsigned long def_mount_opts;
749         long ret = -EINVAL;
750         int blocksize = BLOCK_SIZE;
751         int db_count;
752         int i, j;
753         __le32 features;
754         int err;
755
756         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
757         if (!sbi)
758                 return -ENOMEM;
759         sb->s_fs_info = sbi;
760         sbi->s_sb_block = sb_block;
761
762         /*
763          * See what the current blocksize for the device is, and
764          * use that as the blocksize.  Otherwise (or if the blocksize
765          * is smaller than the default) use the default.
766          * This is important for devices that have a hardware
767          * sectorsize that is larger than the default.
768          */
769         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
770         if (!blocksize) {
771                 printk ("EXT2-fs: unable to set blocksize\n");
772                 goto failed_sbi;
773         }
774
775         /*
776          * If the superblock doesn't start on a hardware sector boundary,
777          * calculate the offset.  
778          */
779         if (blocksize != BLOCK_SIZE) {
780                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
781                 offset = (sb_block*BLOCK_SIZE) % blocksize;
782         } else {
783                 logic_sb_block = sb_block;
784         }
785
786         if (!(bh = sb_bread(sb, logic_sb_block))) {
787                 printk ("EXT2-fs: unable to read superblock\n");
788                 goto failed_sbi;
789         }
790         /*
791          * Note: s_es must be initialized as soon as possible because
792          *       some ext2 macro-instructions depend on its value
793          */
794         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
795         sbi->s_es = es;
796         sb->s_magic = le16_to_cpu(es->s_magic);
797
798         if (sb->s_magic != EXT2_SUPER_MAGIC)
799                 goto cantfind_ext2;
800
801         /* Set defaults before we parse the mount options */
802         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
803         if (def_mount_opts & EXT2_DEFM_DEBUG)
804                 set_opt(sbi->s_mount_opt, DEBUG);
805         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
806                 set_opt(sbi->s_mount_opt, GRPID);
807         if (def_mount_opts & EXT2_DEFM_UID16)
808                 set_opt(sbi->s_mount_opt, NO_UID32);
809 #ifdef CONFIG_EXT2_FS_XATTR
810         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
811                 set_opt(sbi->s_mount_opt, XATTR_USER);
812 #endif
813 #ifdef CONFIG_EXT2_FS_POSIX_ACL
814         if (def_mount_opts & EXT2_DEFM_ACL)
815                 set_opt(sbi->s_mount_opt, POSIX_ACL);
816 #endif
817         
818         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
819                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
820         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
821                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
822         else
823                 set_opt(sbi->s_mount_opt, ERRORS_RO);
824
825         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
826         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
827         
828         set_opt(sbi->s_mount_opt, RESERVATION);
829
830         if (!parse_options ((char *) data, sbi))
831                 goto failed_mount;
832
833         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
834                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
835                  MS_POSIXACL : 0);
836
837         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
838                                     EXT2_MOUNT_XIP if not */
839
840         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
841             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
842              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
843              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
844                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
845                        "running e2fsck is recommended\n");
846         /*
847          * Check feature flags regardless of the revision level, since we
848          * previously didn't change the revision level when setting the flags,
849          * so there is a chance incompat flags are set on a rev 0 filesystem.
850          */
851         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
852         if (features) {
853                 printk("EXT2-fs: %s: couldn't mount because of "
854                        "unsupported optional features (%x).\n",
855                        sb->s_id, le32_to_cpu(features));
856                 goto failed_mount;
857         }
858         if (!(sb->s_flags & MS_RDONLY) &&
859             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
860                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
861                        "unsupported optional features (%x).\n",
862                        sb->s_id, le32_to_cpu(features));
863                 goto failed_mount;
864         }
865
866         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
867
868         if (ext2_use_xip(sb) && blocksize != PAGE_SIZE) {
869                 if (!silent)
870                         printk("XIP: Unsupported blocksize\n");
871                 goto failed_mount;
872         }
873
874         /* If the blocksize doesn't match, re-read the thing.. */
875         if (sb->s_blocksize != blocksize) {
876                 brelse(bh);
877
878                 if (!sb_set_blocksize(sb, blocksize)) {
879                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
880                         goto failed_sbi;
881                 }
882
883                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
884                 offset = (sb_block*BLOCK_SIZE) % blocksize;
885                 bh = sb_bread(sb, logic_sb_block);
886                 if(!bh) {
887                         printk("EXT2-fs: Couldn't read superblock on "
888                                "2nd try.\n");
889                         goto failed_sbi;
890                 }
891                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
892                 sbi->s_es = es;
893                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
894                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
895                         goto failed_mount;
896                 }
897         }
898
899         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
900
901         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
902                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
903                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
904         } else {
905                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
906                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
907                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
908                     !is_power_of_2(sbi->s_inode_size) ||
909                     (sbi->s_inode_size > blocksize)) {
910                         printk ("EXT2-fs: unsupported inode size: %d\n",
911                                 sbi->s_inode_size);
912                         goto failed_mount;
913                 }
914         }
915
916         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
917                                    le32_to_cpu(es->s_log_frag_size);
918         if (sbi->s_frag_size == 0)
919                 goto cantfind_ext2;
920         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
921
922         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
923         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
924         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
925
926         if (EXT2_INODE_SIZE(sb) == 0)
927                 goto cantfind_ext2;
928         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
929         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
930                 goto cantfind_ext2;
931         sbi->s_itb_per_group = sbi->s_inodes_per_group /
932                                         sbi->s_inodes_per_block;
933         sbi->s_desc_per_block = sb->s_blocksize /
934                                         sizeof (struct ext2_group_desc);
935         sbi->s_sbh = bh;
936         sbi->s_mount_state = le16_to_cpu(es->s_state);
937         sbi->s_addr_per_block_bits =
938                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
939         sbi->s_desc_per_block_bits =
940                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
941
942         if (sb->s_magic != EXT2_SUPER_MAGIC)
943                 goto cantfind_ext2;
944
945         if (sb->s_blocksize != bh->b_size) {
946                 if (!silent)
947                         printk ("VFS: Unsupported blocksize on dev "
948                                 "%s.\n", sb->s_id);
949                 goto failed_mount;
950         }
951
952         if (sb->s_blocksize != sbi->s_frag_size) {
953                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
954                         sbi->s_frag_size, sb->s_blocksize);
955                 goto failed_mount;
956         }
957
958         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
959                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
960                         sbi->s_blocks_per_group);
961                 goto failed_mount;
962         }
963         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
964                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
965                         sbi->s_frags_per_group);
966                 goto failed_mount;
967         }
968         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
969                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
970                         sbi->s_inodes_per_group);
971                 goto failed_mount;
972         }
973
974         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
975                 goto cantfind_ext2;
976         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
977                                 le32_to_cpu(es->s_first_data_block) - 1)
978                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
979         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
980                    EXT2_DESC_PER_BLOCK(sb);
981         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
982         if (sbi->s_group_desc == NULL) {
983                 printk ("EXT2-fs: not enough memory\n");
984                 goto failed_mount;
985         }
986         bgl_lock_init(&sbi->s_blockgroup_lock);
987         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
988         if (!sbi->s_debts) {
989                 printk ("EXT2-fs: not enough memory\n");
990                 goto failed_mount_group_desc;
991         }
992         for (i = 0; i < db_count; i++) {
993                 block = descriptor_loc(sb, logic_sb_block, i);
994                 sbi->s_group_desc[i] = sb_bread(sb, block);
995                 if (!sbi->s_group_desc[i]) {
996                         for (j = 0; j < i; j++)
997                                 brelse (sbi->s_group_desc[j]);
998                         printk ("EXT2-fs: unable to read group descriptors\n");
999                         goto failed_mount_group_desc;
1000                 }
1001         }
1002         if (!ext2_check_descriptors (sb)) {
1003                 printk ("EXT2-fs: group descriptors corrupted!\n");
1004                 goto failed_mount2;
1005         }
1006         sbi->s_gdb_count = db_count;
1007         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1008         spin_lock_init(&sbi->s_next_gen_lock);
1009
1010         /* per fileystem reservation list head & lock */
1011         spin_lock_init(&sbi->s_rsv_window_lock);
1012         sbi->s_rsv_window_root = RB_ROOT;
1013         /*
1014          * Add a single, static dummy reservation to the start of the
1015          * reservation window list --- it gives us a placeholder for
1016          * append-at-start-of-list which makes the allocation logic
1017          * _much_ simpler.
1018          */
1019         sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1020         sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1021         sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1022         sbi->s_rsv_window_head.rsv_goal_size = 0;
1023         ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1024
1025         err = percpu_counter_init(&sbi->s_freeblocks_counter,
1026                                 ext2_count_free_blocks(sb));
1027         if (!err) {
1028                 err = percpu_counter_init(&sbi->s_freeinodes_counter,
1029                                 ext2_count_free_inodes(sb));
1030         }
1031         if (!err) {
1032                 err = percpu_counter_init(&sbi->s_dirs_counter,
1033                                 ext2_count_dirs(sb));
1034         }
1035         if (err) {
1036                 printk(KERN_ERR "EXT2-fs: insufficient memory\n");
1037                 goto failed_mount3;
1038         }
1039         /*
1040          * set up enough so that it can read an inode
1041          */
1042         sb->s_op = &ext2_sops;
1043         sb->s_export_op = &ext2_export_ops;
1044         sb->s_xattr = ext2_xattr_handlers;
1045         root = ext2_iget(sb, EXT2_ROOT_INO);
1046         if (IS_ERR(root)) {
1047                 ret = PTR_ERR(root);
1048                 goto failed_mount3;
1049         }
1050         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1051                 iput(root);
1052                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
1053                 goto failed_mount3;
1054         }
1055
1056         sb->s_root = d_alloc_root(root);
1057         if (!sb->s_root) {
1058                 iput(root);
1059                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
1060                 ret = -ENOMEM;
1061                 goto failed_mount3;
1062         }
1063         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1064                 ext2_warning(sb, __FUNCTION__,
1065                         "mounting ext3 filesystem as ext2");
1066         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
1067         return 0;
1068
1069 cantfind_ext2:
1070         if (!silent)
1071                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
1072                        sb->s_id);
1073         goto failed_mount;
1074 failed_mount3:
1075         percpu_counter_destroy(&sbi->s_freeblocks_counter);
1076         percpu_counter_destroy(&sbi->s_freeinodes_counter);
1077         percpu_counter_destroy(&sbi->s_dirs_counter);
1078 failed_mount2:
1079         for (i = 0; i < db_count; i++)
1080                 brelse(sbi->s_group_desc[i]);
1081 failed_mount_group_desc:
1082         kfree(sbi->s_group_desc);
1083         kfree(sbi->s_debts);
1084 failed_mount:
1085         brelse(bh);
1086 failed_sbi:
1087         sb->s_fs_info = NULL;
1088         kfree(sbi);
1089         return ret;
1090 }
1091
1092 static void ext2_commit_super (struct super_block * sb,
1093                                struct ext2_super_block * es)
1094 {
1095         es->s_wtime = cpu_to_le32(get_seconds());
1096         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1097         sb->s_dirt = 0;
1098 }
1099
1100 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
1101 {
1102         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1103         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1104         es->s_wtime = cpu_to_le32(get_seconds());
1105         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1106         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1107         sb->s_dirt = 0;
1108 }
1109
1110 /*
1111  * In the second extended file system, it is not necessary to
1112  * write the super block since we use a mapping of the
1113  * disk super block in a buffer.
1114  *
1115  * However, this function is still used to set the fs valid
1116  * flags to 0.  We need to set this flag to 0 since the fs
1117  * may have been checked while mounted and e2fsck may have
1118  * set s_state to EXT2_VALID_FS after some corrections.
1119  */
1120
1121 void ext2_write_super (struct super_block * sb)
1122 {
1123         struct ext2_super_block * es;
1124         lock_kernel();
1125         if (!(sb->s_flags & MS_RDONLY)) {
1126                 es = EXT2_SB(sb)->s_es;
1127
1128                 if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1129                         ext2_debug ("setting valid to 0\n");
1130                         es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1131                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1132                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1133                         es->s_mtime = cpu_to_le32(get_seconds());
1134                         ext2_sync_super(sb, es);
1135                 } else
1136                         ext2_commit_super (sb, es);
1137         }
1138         sb->s_dirt = 0;
1139         unlock_kernel();
1140 }
1141
1142 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1143 {
1144         struct ext2_sb_info * sbi = EXT2_SB(sb);
1145         struct ext2_super_block * es;
1146         unsigned long old_mount_opt = sbi->s_mount_opt;
1147         struct ext2_mount_options old_opts;
1148         unsigned long old_sb_flags;
1149         int err;
1150
1151         /* Store the old options */
1152         old_sb_flags = sb->s_flags;
1153         old_opts.s_mount_opt = sbi->s_mount_opt;
1154         old_opts.s_resuid = sbi->s_resuid;
1155         old_opts.s_resgid = sbi->s_resgid;
1156
1157         /*
1158          * Allow the "check" option to be passed as a remount option.
1159          */
1160         if (!parse_options (data, sbi)) {
1161                 err = -EINVAL;
1162                 goto restore_opts;
1163         }
1164
1165         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1166                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1167
1168         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1169                                     EXT2_MOUNT_XIP if not */
1170
1171         if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1172                 printk("XIP: Unsupported blocksize\n");
1173                 err = -EINVAL;
1174                 goto restore_opts;
1175         }
1176
1177         es = sbi->s_es;
1178         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1179             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1180             invalidate_inodes(sb))
1181                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1182                              "xip remain in cache (no functional problem)");
1183         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1184                 return 0;
1185         if (*flags & MS_RDONLY) {
1186                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1187                     !(sbi->s_mount_state & EXT2_VALID_FS))
1188                         return 0;
1189                 /*
1190                  * OK, we are remounting a valid rw partition rdonly, so set
1191                  * the rdonly flag and then mark the partition as valid again.
1192                  */
1193                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1194                 es->s_mtime = cpu_to_le32(get_seconds());
1195         } else {
1196                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1197                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1198                 if (ret) {
1199                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1200                                "unsupported optional features (%x).\n",
1201                                sb->s_id, le32_to_cpu(ret));
1202                         err = -EROFS;
1203                         goto restore_opts;
1204                 }
1205                 /*
1206                  * Mounting a RDONLY partition read-write, so reread and
1207                  * store the current valid flag.  (It may have been changed
1208                  * by e2fsck since we originally mounted the partition.)
1209                  */
1210                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1211                 if (!ext2_setup_super (sb, es, 0))
1212                         sb->s_flags &= ~MS_RDONLY;
1213         }
1214         ext2_sync_super(sb, es);
1215         return 0;
1216 restore_opts:
1217         sbi->s_mount_opt = old_opts.s_mount_opt;
1218         sbi->s_resuid = old_opts.s_resuid;
1219         sbi->s_resgid = old_opts.s_resgid;
1220         sb->s_flags = old_sb_flags;
1221         return err;
1222 }
1223
1224 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1225 {
1226         struct super_block *sb = dentry->d_sb;
1227         struct ext2_sb_info *sbi = EXT2_SB(sb);
1228         struct ext2_super_block *es = sbi->s_es;
1229         u64 fsid;
1230
1231         if (test_opt (sb, MINIX_DF))
1232                 sbi->s_overhead_last = 0;
1233         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1234                 unsigned long i, overhead = 0;
1235                 smp_rmb();
1236
1237                 /*
1238                  * Compute the overhead (FS structures). This is constant
1239                  * for a given filesystem unless the number of block groups
1240                  * changes so we cache the previous value until it does.
1241                  */
1242
1243                 /*
1244                  * All of the blocks before first_data_block are
1245                  * overhead
1246                  */
1247                 overhead = le32_to_cpu(es->s_first_data_block);
1248
1249                 /*
1250                  * Add the overhead attributed to the superblock and
1251                  * block group descriptors.  If the sparse superblocks
1252                  * feature is turned on, then not all groups have this.
1253                  */
1254                 for (i = 0; i < sbi->s_groups_count; i++)
1255                         overhead += ext2_bg_has_super(sb, i) +
1256                                 ext2_bg_num_gdb(sb, i);
1257
1258                 /*
1259                  * Every block group has an inode bitmap, a block
1260                  * bitmap, and an inode table.
1261                  */
1262                 overhead += (sbi->s_groups_count *
1263                              (2 + sbi->s_itb_per_group));
1264                 sbi->s_overhead_last = overhead;
1265                 smp_wmb();
1266                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1267         }
1268
1269         buf->f_type = EXT2_SUPER_MAGIC;
1270         buf->f_bsize = sb->s_blocksize;
1271         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1272         buf->f_bfree = ext2_count_free_blocks(sb);
1273         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1274         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1275         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1276                 buf->f_bavail = 0;
1277         buf->f_files = le32_to_cpu(es->s_inodes_count);
1278         buf->f_ffree = ext2_count_free_inodes(sb);
1279         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1280         buf->f_namelen = EXT2_NAME_LEN;
1281         fsid = le64_to_cpup((void *)es->s_uuid) ^
1282                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1283         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1284         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1285         return 0;
1286 }
1287
1288 static int ext2_get_sb(struct file_system_type *fs_type,
1289         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1290 {
1291         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1292 }
1293
1294 #ifdef CONFIG_QUOTA
1295
1296 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1297  * acquiring the locks... As quota files are never truncated and quota code
1298  * itself serializes the operations (and noone else should touch the files)
1299  * we don't have to be afraid of races */
1300 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1301                                size_t len, loff_t off)
1302 {
1303         struct inode *inode = sb_dqopt(sb)->files[type];
1304         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1305         int err = 0;
1306         int offset = off & (sb->s_blocksize - 1);
1307         int tocopy;
1308         size_t toread;
1309         struct buffer_head tmp_bh;
1310         struct buffer_head *bh;
1311         loff_t i_size = i_size_read(inode);
1312
1313         if (off > i_size)
1314                 return 0;
1315         if (off+len > i_size)
1316                 len = i_size-off;
1317         toread = len;
1318         while (toread > 0) {
1319                 tocopy = sb->s_blocksize - offset < toread ?
1320                                 sb->s_blocksize - offset : toread;
1321
1322                 tmp_bh.b_state = 0;
1323                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1324                 if (err < 0)
1325                         return err;
1326                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1327                         memset(data, 0, tocopy);
1328                 else {
1329                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1330                         if (!bh)
1331                                 return -EIO;
1332                         memcpy(data, bh->b_data+offset, tocopy);
1333                         brelse(bh);
1334                 }
1335                 offset = 0;
1336                 toread -= tocopy;
1337                 data += tocopy;
1338                 blk++;
1339         }
1340         return len;
1341 }
1342
1343 /* Write to quotafile */
1344 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1345                                 const char *data, size_t len, loff_t off)
1346 {
1347         struct inode *inode = sb_dqopt(sb)->files[type];
1348         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1349         int err = 0;
1350         int offset = off & (sb->s_blocksize - 1);
1351         int tocopy;
1352         size_t towrite = len;
1353         struct buffer_head tmp_bh;
1354         struct buffer_head *bh;
1355
1356         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1357         while (towrite > 0) {
1358                 tocopy = sb->s_blocksize - offset < towrite ?
1359                                 sb->s_blocksize - offset : towrite;
1360
1361                 tmp_bh.b_state = 0;
1362                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1363                 if (err < 0)
1364                         goto out;
1365                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1366                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1367                 else
1368                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1369                 if (!bh) {
1370                         err = -EIO;
1371                         goto out;
1372                 }
1373                 lock_buffer(bh);
1374                 memcpy(bh->b_data+offset, data, tocopy);
1375                 flush_dcache_page(bh->b_page);
1376                 set_buffer_uptodate(bh);
1377                 mark_buffer_dirty(bh);
1378                 unlock_buffer(bh);
1379                 brelse(bh);
1380                 offset = 0;
1381                 towrite -= tocopy;
1382                 data += tocopy;
1383                 blk++;
1384         }
1385 out:
1386         if (len == towrite)
1387                 return err;
1388         if (inode->i_size < off+len-towrite)
1389                 i_size_write(inode, off+len-towrite);
1390         inode->i_version++;
1391         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1392         mark_inode_dirty(inode);
1393         mutex_unlock(&inode->i_mutex);
1394         return len - towrite;
1395 }
1396
1397 #endif
1398
1399 static struct file_system_type ext2_fs_type = {
1400         .owner          = THIS_MODULE,
1401         .name           = "ext2",
1402         .get_sb         = ext2_get_sb,
1403         .kill_sb        = kill_block_super,
1404         .fs_flags       = FS_REQUIRES_DEV,
1405 };
1406
1407 static int __init init_ext2_fs(void)
1408 {
1409         int err = init_ext2_xattr();
1410         if (err)
1411                 return err;
1412         err = init_inodecache();
1413         if (err)
1414                 goto out1;
1415         err = register_filesystem(&ext2_fs_type);
1416         if (err)
1417                 goto out;
1418         return 0;
1419 out:
1420         destroy_inodecache();
1421 out1:
1422         exit_ext2_xattr();
1423         return err;
1424 }
1425
1426 static void __exit exit_ext2_fs(void)
1427 {
1428         unregister_filesystem(&ext2_fs_type);
1429         destroy_inodecache();
1430         exit_ext2_xattr();
1431 }
1432
1433 module_init(init_ext2_fs)
1434 module_exit(exit_ext2_fs)