switch ext2 to inode->i_acl
[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 <linux/quotaops.h>
35 #include <asm/uaccess.h>
36 #include "ext2.h"
37 #include "xattr.h"
38 #include "acl.h"
39 #include "xip.h"
40
41 static void ext2_sync_super(struct super_block *sb,
42                             struct ext2_super_block *es);
43 static int ext2_remount (struct super_block * sb, int * flags, char * data);
44 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
45 static int ext2_sync_fs(struct super_block *sb, int wait);
46
47 void ext2_error (struct super_block * sb, const char * function,
48                  const char * fmt, ...)
49 {
50         va_list args;
51         struct ext2_sb_info *sbi = EXT2_SB(sb);
52         struct ext2_super_block *es = sbi->s_es;
53
54         if (!(sb->s_flags & MS_RDONLY)) {
55                 sbi->s_mount_state |= EXT2_ERROR_FS;
56                 es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
57                 ext2_sync_super(sb, es);
58         }
59
60         va_start(args, fmt);
61         printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
62         vprintk(fmt, args);
63         printk("\n");
64         va_end(args);
65
66         if (test_opt(sb, ERRORS_PANIC))
67                 panic("EXT2-fs panic from previous error\n");
68         if (test_opt(sb, ERRORS_RO)) {
69                 printk("Remounting filesystem read-only\n");
70                 sb->s_flags |= MS_RDONLY;
71         }
72 }
73
74 void ext2_warning (struct super_block * sb, const char * function,
75                    const char * fmt, ...)
76 {
77         va_list args;
78
79         va_start(args, fmt);
80         printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
81                sb->s_id, function);
82         vprintk(fmt, args);
83         printk("\n");
84         va_end(args);
85 }
86
87 void ext2_update_dynamic_rev(struct super_block *sb)
88 {
89         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
90
91         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
92                 return;
93
94         ext2_warning(sb, __func__,
95                      "updating to rev %d because of new feature flag, "
96                      "running e2fsck is recommended",
97                      EXT2_DYNAMIC_REV);
98
99         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
100         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
101         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
102         /* leave es->s_feature_*compat flags alone */
103         /* es->s_uuid will be set by e2fsck if empty */
104
105         /*
106          * The rest of the superblock fields should be zero, and if not it
107          * means they are likely already in use, so leave them alone.  We
108          * can leave it up to e2fsck to clean up any inconsistencies there.
109          */
110 }
111
112 static void ext2_put_super (struct super_block * sb)
113 {
114         int db_count;
115         int i;
116         struct ext2_sb_info *sbi = EXT2_SB(sb);
117
118         lock_kernel();
119
120         if (sb->s_dirt)
121                 ext2_write_super(sb);
122
123         ext2_xattr_put_super(sb);
124         if (!(sb->s_flags & MS_RDONLY)) {
125                 struct ext2_super_block *es = sbi->s_es;
126
127                 es->s_state = cpu_to_le16(sbi->s_mount_state);
128                 ext2_sync_super(sb, es);
129         }
130         db_count = sbi->s_gdb_count;
131         for (i = 0; i < db_count; i++)
132                 if (sbi->s_group_desc[i])
133                         brelse (sbi->s_group_desc[i]);
134         kfree(sbi->s_group_desc);
135         kfree(sbi->s_debts);
136         percpu_counter_destroy(&sbi->s_freeblocks_counter);
137         percpu_counter_destroy(&sbi->s_freeinodes_counter);
138         percpu_counter_destroy(&sbi->s_dirs_counter);
139         brelse (sbi->s_sbh);
140         sb->s_fs_info = NULL;
141         kfree(sbi->s_blockgroup_lock);
142         kfree(sbi);
143
144         unlock_kernel();
145 }
146
147 static struct kmem_cache * ext2_inode_cachep;
148
149 static struct inode *ext2_alloc_inode(struct super_block *sb)
150 {
151         struct ext2_inode_info *ei;
152         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
153         if (!ei)
154                 return NULL;
155         ei->i_block_alloc_info = NULL;
156         ei->vfs_inode.i_version = 1;
157         return &ei->vfs_inode;
158 }
159
160 static void ext2_destroy_inode(struct inode *inode)
161 {
162         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
163 }
164
165 static void init_once(void *foo)
166 {
167         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
168
169         rwlock_init(&ei->i_meta_lock);
170 #ifdef CONFIG_EXT2_FS_XATTR
171         init_rwsem(&ei->xattr_sem);
172 #endif
173         mutex_init(&ei->truncate_mutex);
174         inode_init_once(&ei->vfs_inode);
175 }
176
177 static int init_inodecache(void)
178 {
179         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
180                                              sizeof(struct ext2_inode_info),
181                                              0, (SLAB_RECLAIM_ACCOUNT|
182                                                 SLAB_MEM_SPREAD),
183                                              init_once);
184         if (ext2_inode_cachep == NULL)
185                 return -ENOMEM;
186         return 0;
187 }
188
189 static void destroy_inodecache(void)
190 {
191         kmem_cache_destroy(ext2_inode_cachep);
192 }
193
194 static void ext2_clear_inode(struct inode *inode)
195 {
196         struct ext2_block_alloc_info *rsv = EXT2_I(inode)->i_block_alloc_info;
197         ext2_discard_reservation(inode);
198         EXT2_I(inode)->i_block_alloc_info = NULL;
199         if (unlikely(rsv))
200                 kfree(rsv);
201 }
202
203 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
204 {
205         struct super_block *sb = vfs->mnt_sb;
206         struct ext2_sb_info *sbi = EXT2_SB(sb);
207         struct ext2_super_block *es = sbi->s_es;
208         unsigned long def_mount_opts;
209
210         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
211
212         if (sbi->s_sb_block != 1)
213                 seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
214         if (test_opt(sb, MINIX_DF))
215                 seq_puts(seq, ",minixdf");
216         if (test_opt(sb, GRPID))
217                 seq_puts(seq, ",grpid");
218         if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
219                 seq_puts(seq, ",nogrpid");
220         if (sbi->s_resuid != EXT2_DEF_RESUID ||
221             le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
222                 seq_printf(seq, ",resuid=%u", sbi->s_resuid);
223         }
224         if (sbi->s_resgid != EXT2_DEF_RESGID ||
225             le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
226                 seq_printf(seq, ",resgid=%u", sbi->s_resgid);
227         }
228         if (test_opt(sb, ERRORS_RO)) {
229                 int def_errors = le16_to_cpu(es->s_errors);
230
231                 if (def_errors == EXT2_ERRORS_PANIC ||
232                     def_errors == EXT2_ERRORS_CONTINUE) {
233                         seq_puts(seq, ",errors=remount-ro");
234                 }
235         }
236         if (test_opt(sb, ERRORS_CONT))
237                 seq_puts(seq, ",errors=continue");
238         if (test_opt(sb, ERRORS_PANIC))
239                 seq_puts(seq, ",errors=panic");
240         if (test_opt(sb, NO_UID32))
241                 seq_puts(seq, ",nouid32");
242         if (test_opt(sb, DEBUG))
243                 seq_puts(seq, ",debug");
244         if (test_opt(sb, OLDALLOC))
245                 seq_puts(seq, ",oldalloc");
246
247 #ifdef CONFIG_EXT2_FS_XATTR
248         if (test_opt(sb, XATTR_USER))
249                 seq_puts(seq, ",user_xattr");
250         if (!test_opt(sb, XATTR_USER) &&
251             (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
252                 seq_puts(seq, ",nouser_xattr");
253         }
254 #endif
255
256 #ifdef CONFIG_EXT2_FS_POSIX_ACL
257         if (test_opt(sb, POSIX_ACL))
258                 seq_puts(seq, ",acl");
259         if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
260                 seq_puts(seq, ",noacl");
261 #endif
262
263         if (test_opt(sb, NOBH))
264                 seq_puts(seq, ",nobh");
265
266 #if defined(CONFIG_QUOTA)
267         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
268                 seq_puts(seq, ",usrquota");
269
270         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
271                 seq_puts(seq, ",grpquota");
272 #endif
273
274 #if defined(CONFIG_EXT2_FS_XIP)
275         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
276                 seq_puts(seq, ",xip");
277 #endif
278
279         if (!test_opt(sb, RESERVATION))
280                 seq_puts(seq, ",noreservation");
281
282         return 0;
283 }
284
285 #ifdef CONFIG_QUOTA
286 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
287 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
288 #endif
289
290 static const struct super_operations ext2_sops = {
291         .alloc_inode    = ext2_alloc_inode,
292         .destroy_inode  = ext2_destroy_inode,
293         .write_inode    = ext2_write_inode,
294         .delete_inode   = ext2_delete_inode,
295         .put_super      = ext2_put_super,
296         .write_super    = ext2_write_super,
297         .sync_fs        = ext2_sync_fs,
298         .statfs         = ext2_statfs,
299         .remount_fs     = ext2_remount,
300         .clear_inode    = ext2_clear_inode,
301         .show_options   = ext2_show_options,
302 #ifdef CONFIG_QUOTA
303         .quota_read     = ext2_quota_read,
304         .quota_write    = ext2_quota_write,
305 #endif
306 };
307
308 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
309                 u64 ino, u32 generation)
310 {
311         struct inode *inode;
312
313         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
314                 return ERR_PTR(-ESTALE);
315         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
316                 return ERR_PTR(-ESTALE);
317
318         /* iget isn't really right if the inode is currently unallocated!!
319          * ext2_read_inode currently does appropriate checks, but
320          * it might be "neater" to call ext2_get_inode first and check
321          * if the inode is valid.....
322          */
323         inode = ext2_iget(sb, ino);
324         if (IS_ERR(inode))
325                 return ERR_CAST(inode);
326         if (generation && inode->i_generation != generation) {
327                 /* we didn't find the right inode.. */
328                 iput(inode);
329                 return ERR_PTR(-ESTALE);
330         }
331         return inode;
332 }
333
334 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
335                 int fh_len, int fh_type)
336 {
337         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
338                                     ext2_nfs_get_inode);
339 }
340
341 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
342                 int fh_len, int fh_type)
343 {
344         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
345                                     ext2_nfs_get_inode);
346 }
347
348 /* Yes, most of these are left as NULL!!
349  * A NULL value implies the default, which works with ext2-like file
350  * systems, but can be improved upon.
351  * Currently only get_parent is required.
352  */
353 static const struct export_operations ext2_export_ops = {
354         .fh_to_dentry = ext2_fh_to_dentry,
355         .fh_to_parent = ext2_fh_to_parent,
356         .get_parent = ext2_get_parent,
357 };
358
359 static unsigned long get_sb_block(void **data)
360 {
361         unsigned long   sb_block;
362         char            *options = (char *) *data;
363
364         if (!options || strncmp(options, "sb=", 3) != 0)
365                 return 1;       /* Default location */
366         options += 3;
367         sb_block = simple_strtoul(options, &options, 0);
368         if (*options && *options != ',') {
369                 printk("EXT2-fs: Invalid sb specification: %s\n",
370                        (char *) *data);
371                 return 1;
372         }
373         if (*options == ',')
374                 options++;
375         *data = (void *) options;
376         return sb_block;
377 }
378
379 enum {
380         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
381         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
382         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
383         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
384         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
385         Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
386 };
387
388 static const match_table_t tokens = {
389         {Opt_bsd_df, "bsddf"},
390         {Opt_minix_df, "minixdf"},
391         {Opt_grpid, "grpid"},
392         {Opt_grpid, "bsdgroups"},
393         {Opt_nogrpid, "nogrpid"},
394         {Opt_nogrpid, "sysvgroups"},
395         {Opt_resgid, "resgid=%u"},
396         {Opt_resuid, "resuid=%u"},
397         {Opt_sb, "sb=%u"},
398         {Opt_err_cont, "errors=continue"},
399         {Opt_err_panic, "errors=panic"},
400         {Opt_err_ro, "errors=remount-ro"},
401         {Opt_nouid32, "nouid32"},
402         {Opt_nocheck, "check=none"},
403         {Opt_nocheck, "nocheck"},
404         {Opt_debug, "debug"},
405         {Opt_oldalloc, "oldalloc"},
406         {Opt_orlov, "orlov"},
407         {Opt_nobh, "nobh"},
408         {Opt_user_xattr, "user_xattr"},
409         {Opt_nouser_xattr, "nouser_xattr"},
410         {Opt_acl, "acl"},
411         {Opt_noacl, "noacl"},
412         {Opt_xip, "xip"},
413         {Opt_grpquota, "grpquota"},
414         {Opt_ignore, "noquota"},
415         {Opt_quota, "quota"},
416         {Opt_usrquota, "usrquota"},
417         {Opt_reservation, "reservation"},
418         {Opt_noreservation, "noreservation"},
419         {Opt_err, NULL}
420 };
421
422 static int parse_options (char * options,
423                           struct ext2_sb_info *sbi)
424 {
425         char * p;
426         substring_t args[MAX_OPT_ARGS];
427         int option;
428
429         if (!options)
430                 return 1;
431
432         while ((p = strsep (&options, ",")) != NULL) {
433                 int token;
434                 if (!*p)
435                         continue;
436
437                 token = match_token(p, tokens, args);
438                 switch (token) {
439                 case Opt_bsd_df:
440                         clear_opt (sbi->s_mount_opt, MINIX_DF);
441                         break;
442                 case Opt_minix_df:
443                         set_opt (sbi->s_mount_opt, MINIX_DF);
444                         break;
445                 case Opt_grpid:
446                         set_opt (sbi->s_mount_opt, GRPID);
447                         break;
448                 case Opt_nogrpid:
449                         clear_opt (sbi->s_mount_opt, GRPID);
450                         break;
451                 case Opt_resuid:
452                         if (match_int(&args[0], &option))
453                                 return 0;
454                         sbi->s_resuid = option;
455                         break;
456                 case Opt_resgid:
457                         if (match_int(&args[0], &option))
458                                 return 0;
459                         sbi->s_resgid = option;
460                         break;
461                 case Opt_sb:
462                         /* handled by get_sb_block() instead of here */
463                         /* *sb_block = match_int(&args[0]); */
464                         break;
465                 case Opt_err_panic:
466                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
467                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
468                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
469                         break;
470                 case Opt_err_ro:
471                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
472                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
473                         set_opt (sbi->s_mount_opt, ERRORS_RO);
474                         break;
475                 case Opt_err_cont:
476                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
477                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
478                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
479                         break;
480                 case Opt_nouid32:
481                         set_opt (sbi->s_mount_opt, NO_UID32);
482                         break;
483                 case Opt_nocheck:
484                         clear_opt (sbi->s_mount_opt, CHECK);
485                         break;
486                 case Opt_debug:
487                         set_opt (sbi->s_mount_opt, DEBUG);
488                         break;
489                 case Opt_oldalloc:
490                         set_opt (sbi->s_mount_opt, OLDALLOC);
491                         break;
492                 case Opt_orlov:
493                         clear_opt (sbi->s_mount_opt, OLDALLOC);
494                         break;
495                 case Opt_nobh:
496                         set_opt (sbi->s_mount_opt, NOBH);
497                         break;
498 #ifdef CONFIG_EXT2_FS_XATTR
499                 case Opt_user_xattr:
500                         set_opt (sbi->s_mount_opt, XATTR_USER);
501                         break;
502                 case Opt_nouser_xattr:
503                         clear_opt (sbi->s_mount_opt, XATTR_USER);
504                         break;
505 #else
506                 case Opt_user_xattr:
507                 case Opt_nouser_xattr:
508                         printk("EXT2 (no)user_xattr options not supported\n");
509                         break;
510 #endif
511 #ifdef CONFIG_EXT2_FS_POSIX_ACL
512                 case Opt_acl:
513                         set_opt(sbi->s_mount_opt, POSIX_ACL);
514                         break;
515                 case Opt_noacl:
516                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
517                         break;
518 #else
519                 case Opt_acl:
520                 case Opt_noacl:
521                         printk("EXT2 (no)acl options not supported\n");
522                         break;
523 #endif
524                 case Opt_xip:
525 #ifdef CONFIG_EXT2_FS_XIP
526                         set_opt (sbi->s_mount_opt, XIP);
527 #else
528                         printk("EXT2 xip option not supported\n");
529 #endif
530                         break;
531
532 #if defined(CONFIG_QUOTA)
533                 case Opt_quota:
534                 case Opt_usrquota:
535                         set_opt(sbi->s_mount_opt, USRQUOTA);
536                         break;
537
538                 case Opt_grpquota:
539                         set_opt(sbi->s_mount_opt, GRPQUOTA);
540                         break;
541 #else
542                 case Opt_quota:
543                 case Opt_usrquota:
544                 case Opt_grpquota:
545                         printk(KERN_ERR
546                                 "EXT2-fs: quota operations not supported.\n");
547
548                         break;
549 #endif
550
551                 case Opt_reservation:
552                         set_opt(sbi->s_mount_opt, RESERVATION);
553                         printk("reservations ON\n");
554                         break;
555                 case Opt_noreservation:
556                         clear_opt(sbi->s_mount_opt, RESERVATION);
557                         printk("reservations OFF\n");
558                         break;
559                 case Opt_ignore:
560                         break;
561                 default:
562                         return 0;
563                 }
564         }
565         return 1;
566 }
567
568 static int ext2_setup_super (struct super_block * sb,
569                               struct ext2_super_block * es,
570                               int read_only)
571 {
572         int res = 0;
573         struct ext2_sb_info *sbi = EXT2_SB(sb);
574
575         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
576                 printk ("EXT2-fs warning: revision level too high, "
577                         "forcing read-only mode\n");
578                 res = MS_RDONLY;
579         }
580         if (read_only)
581                 return res;
582         if (!(sbi->s_mount_state & EXT2_VALID_FS))
583                 printk ("EXT2-fs warning: mounting unchecked fs, "
584                         "running e2fsck is recommended\n");
585         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
586                 printk ("EXT2-fs warning: mounting fs with errors, "
587                         "running e2fsck is recommended\n");
588         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
589                  le16_to_cpu(es->s_mnt_count) >=
590                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
591                 printk ("EXT2-fs warning: maximal mount count reached, "
592                         "running e2fsck is recommended\n");
593         else if (le32_to_cpu(es->s_checkinterval) &&
594                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
595                 printk ("EXT2-fs warning: checktime reached, "
596                         "running e2fsck is recommended\n");
597         if (!le16_to_cpu(es->s_max_mnt_count))
598                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
599         le16_add_cpu(&es->s_mnt_count, 1);
600         ext2_write_super(sb);
601         if (test_opt (sb, DEBUG))
602                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
603                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
604                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
605                         sbi->s_frag_size,
606                         sbi->s_groups_count,
607                         EXT2_BLOCKS_PER_GROUP(sb),
608                         EXT2_INODES_PER_GROUP(sb),
609                         sbi->s_mount_opt);
610         return res;
611 }
612
613 static int ext2_check_descriptors(struct super_block *sb)
614 {
615         int i;
616         struct ext2_sb_info *sbi = EXT2_SB(sb);
617
618         ext2_debug ("Checking group descriptors");
619
620         for (i = 0; i < sbi->s_groups_count; i++) {
621                 struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
622                 ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
623                 ext2_fsblk_t last_block;
624
625                 if (i == sbi->s_groups_count - 1)
626                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
627                 else
628                         last_block = first_block +
629                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
630
631                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
632                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
633                 {
634                         ext2_error (sb, "ext2_check_descriptors",
635                                     "Block bitmap for group %d"
636                                     " not in group (block %lu)!",
637                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
638                         return 0;
639                 }
640                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
641                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
642                 {
643                         ext2_error (sb, "ext2_check_descriptors",
644                                     "Inode bitmap for group %d"
645                                     " not in group (block %lu)!",
646                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
647                         return 0;
648                 }
649                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
650                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
651                     last_block)
652                 {
653                         ext2_error (sb, "ext2_check_descriptors",
654                                     "Inode table for group %d"
655                                     " not in group (block %lu)!",
656                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
657                         return 0;
658                 }
659         }
660         return 1;
661 }
662
663 /*
664  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
665  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
666  * We need to be 1 filesystem block less than the 2^32 sector limit.
667  */
668 static loff_t ext2_max_size(int bits)
669 {
670         loff_t res = EXT2_NDIR_BLOCKS;
671         int meta_blocks;
672         loff_t upper_limit;
673
674         /* This is calculated to be the largest file size for a
675          * dense, file such that the total number of
676          * sectors in the file, including data and all indirect blocks,
677          * does not exceed 2^32 -1
678          * __u32 i_blocks representing the total number of
679          * 512 bytes blocks of the file
680          */
681         upper_limit = (1LL << 32) - 1;
682
683         /* total blocks in file system block size */
684         upper_limit >>= (bits - 9);
685
686
687         /* indirect blocks */
688         meta_blocks = 1;
689         /* double indirect blocks */
690         meta_blocks += 1 + (1LL << (bits-2));
691         /* tripple indirect blocks */
692         meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
693
694         upper_limit -= meta_blocks;
695         upper_limit <<= bits;
696
697         res += 1LL << (bits-2);
698         res += 1LL << (2*(bits-2));
699         res += 1LL << (3*(bits-2));
700         res <<= bits;
701         if (res > upper_limit)
702                 res = upper_limit;
703
704         if (res > MAX_LFS_FILESIZE)
705                 res = MAX_LFS_FILESIZE;
706
707         return res;
708 }
709
710 static unsigned long descriptor_loc(struct super_block *sb,
711                                     unsigned long logic_sb_block,
712                                     int nr)
713 {
714         struct ext2_sb_info *sbi = EXT2_SB(sb);
715         unsigned long bg, first_meta_bg;
716         int has_super = 0;
717         
718         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
719
720         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
721             nr < first_meta_bg)
722                 return (logic_sb_block + nr + 1);
723         bg = sbi->s_desc_per_block * nr;
724         if (ext2_bg_has_super(sb, bg))
725                 has_super = 1;
726
727         return ext2_group_first_block_no(sb, bg) + has_super;
728 }
729
730 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
731 {
732         struct buffer_head * bh;
733         struct ext2_sb_info * sbi;
734         struct ext2_super_block * es;
735         struct inode *root;
736         unsigned long block;
737         unsigned long sb_block = get_sb_block(&data);
738         unsigned long logic_sb_block;
739         unsigned long offset = 0;
740         unsigned long def_mount_opts;
741         long ret = -EINVAL;
742         int blocksize = BLOCK_SIZE;
743         int db_count;
744         int i, j;
745         __le32 features;
746         int err;
747
748         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
749         if (!sbi)
750                 return -ENOMEM;
751
752         sbi->s_blockgroup_lock =
753                 kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
754         if (!sbi->s_blockgroup_lock) {
755                 kfree(sbi);
756                 return -ENOMEM;
757         }
758         sb->s_fs_info = sbi;
759         sbi->s_sb_block = sb_block;
760
761         /*
762          * See what the current blocksize for the device is, and
763          * use that as the blocksize.  Otherwise (or if the blocksize
764          * is smaller than the default) use the default.
765          * This is important for devices that have a hardware
766          * sectorsize that is larger than the default.
767          */
768         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
769         if (!blocksize) {
770                 printk ("EXT2-fs: unable to set blocksize\n");
771                 goto failed_sbi;
772         }
773
774         /*
775          * If the superblock doesn't start on a hardware sector boundary,
776          * calculate the offset.  
777          */
778         if (blocksize != BLOCK_SIZE) {
779                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
780                 offset = (sb_block*BLOCK_SIZE) % blocksize;
781         } else {
782                 logic_sb_block = sb_block;
783         }
784
785         if (!(bh = sb_bread(sb, logic_sb_block))) {
786                 printk ("EXT2-fs: unable to read superblock\n");
787                 goto failed_sbi;
788         }
789         /*
790          * Note: s_es must be initialized as soon as possible because
791          *       some ext2 macro-instructions depend on its value
792          */
793         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
794         sbi->s_es = es;
795         sb->s_magic = le16_to_cpu(es->s_magic);
796
797         if (sb->s_magic != EXT2_SUPER_MAGIC)
798                 goto cantfind_ext2;
799
800         /* Set defaults before we parse the mount options */
801         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
802         if (def_mount_opts & EXT2_DEFM_DEBUG)
803                 set_opt(sbi->s_mount_opt, DEBUG);
804         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
805                 set_opt(sbi->s_mount_opt, GRPID);
806         if (def_mount_opts & EXT2_DEFM_UID16)
807                 set_opt(sbi->s_mount_opt, NO_UID32);
808 #ifdef CONFIG_EXT2_FS_XATTR
809         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
810                 set_opt(sbi->s_mount_opt, XATTR_USER);
811 #endif
812 #ifdef CONFIG_EXT2_FS_POSIX_ACL
813         if (def_mount_opts & EXT2_DEFM_ACL)
814                 set_opt(sbi->s_mount_opt, POSIX_ACL);
815 #endif
816         
817         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
818                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
819         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
820                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
821         else
822                 set_opt(sbi->s_mount_opt, ERRORS_RO);
823
824         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
825         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
826         
827         set_opt(sbi->s_mount_opt, RESERVATION);
828
829         if (!parse_options ((char *) data, sbi))
830                 goto failed_mount;
831
832         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
833                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
834                  MS_POSIXACL : 0);
835
836         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
837                                     EXT2_MOUNT_XIP if not */
838
839         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
840             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
841              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
842              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
843                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
844                        "running e2fsck is recommended\n");
845         /*
846          * Check feature flags regardless of the revision level, since we
847          * previously didn't change the revision level when setting the flags,
848          * so there is a chance incompat flags are set on a rev 0 filesystem.
849          */
850         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
851         if (features) {
852                 printk("EXT2-fs: %s: couldn't mount because of "
853                        "unsupported optional features (%x).\n",
854                        sb->s_id, le32_to_cpu(features));
855                 goto failed_mount;
856         }
857         if (!(sb->s_flags & MS_RDONLY) &&
858             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
859                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
860                        "unsupported optional features (%x).\n",
861                        sb->s_id, le32_to_cpu(features));
862                 goto failed_mount;
863         }
864
865         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
866
867         if (ext2_use_xip(sb) && blocksize != PAGE_SIZE) {
868                 if (!silent)
869                         printk("XIP: Unsupported blocksize\n");
870                 goto failed_mount;
871         }
872
873         /* If the blocksize doesn't match, re-read the thing.. */
874         if (sb->s_blocksize != blocksize) {
875                 brelse(bh);
876
877                 if (!sb_set_blocksize(sb, blocksize)) {
878                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
879                         goto failed_sbi;
880                 }
881
882                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
883                 offset = (sb_block*BLOCK_SIZE) % blocksize;
884                 bh = sb_bread(sb, logic_sb_block);
885                 if(!bh) {
886                         printk("EXT2-fs: Couldn't read superblock on "
887                                "2nd try.\n");
888                         goto failed_sbi;
889                 }
890                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
891                 sbi->s_es = es;
892                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
893                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
894                         goto failed_mount;
895                 }
896         }
897
898         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
899
900         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
901                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
902                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
903         } else {
904                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
905                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
906                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
907                     !is_power_of_2(sbi->s_inode_size) ||
908                     (sbi->s_inode_size > blocksize)) {
909                         printk ("EXT2-fs: unsupported inode size: %d\n",
910                                 sbi->s_inode_size);
911                         goto failed_mount;
912                 }
913         }
914
915         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
916                                    le32_to_cpu(es->s_log_frag_size);
917         if (sbi->s_frag_size == 0)
918                 goto cantfind_ext2;
919         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
920
921         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
922         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
923         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
924
925         if (EXT2_INODE_SIZE(sb) == 0)
926                 goto cantfind_ext2;
927         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
928         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
929                 goto cantfind_ext2;
930         sbi->s_itb_per_group = sbi->s_inodes_per_group /
931                                         sbi->s_inodes_per_block;
932         sbi->s_desc_per_block = sb->s_blocksize /
933                                         sizeof (struct ext2_group_desc);
934         sbi->s_sbh = bh;
935         sbi->s_mount_state = le16_to_cpu(es->s_state);
936         sbi->s_addr_per_block_bits =
937                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
938         sbi->s_desc_per_block_bits =
939                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
940
941         if (sb->s_magic != EXT2_SUPER_MAGIC)
942                 goto cantfind_ext2;
943
944         if (sb->s_blocksize != bh->b_size) {
945                 if (!silent)
946                         printk ("VFS: Unsupported blocksize on dev "
947                                 "%s.\n", sb->s_id);
948                 goto failed_mount;
949         }
950
951         if (sb->s_blocksize != sbi->s_frag_size) {
952                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
953                         sbi->s_frag_size, sb->s_blocksize);
954                 goto failed_mount;
955         }
956
957         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
958                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
959                         sbi->s_blocks_per_group);
960                 goto failed_mount;
961         }
962         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
963                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
964                         sbi->s_frags_per_group);
965                 goto failed_mount;
966         }
967         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
968                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
969                         sbi->s_inodes_per_group);
970                 goto failed_mount;
971         }
972
973         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
974                 goto cantfind_ext2;
975         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
976                                 le32_to_cpu(es->s_first_data_block) - 1)
977                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
978         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
979                    EXT2_DESC_PER_BLOCK(sb);
980         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
981         if (sbi->s_group_desc == NULL) {
982                 printk ("EXT2-fs: not enough memory\n");
983                 goto failed_mount;
984         }
985         bgl_lock_init(sbi->s_blockgroup_lock);
986         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
987         if (!sbi->s_debts) {
988                 printk ("EXT2-fs: not enough memory\n");
989                 goto failed_mount_group_desc;
990         }
991         for (i = 0; i < db_count; i++) {
992                 block = descriptor_loc(sb, logic_sb_block, i);
993                 sbi->s_group_desc[i] = sb_bread(sb, block);
994                 if (!sbi->s_group_desc[i]) {
995                         for (j = 0; j < i; j++)
996                                 brelse (sbi->s_group_desc[j]);
997                         printk ("EXT2-fs: unable to read group descriptors\n");
998                         goto failed_mount_group_desc;
999                 }
1000         }
1001         if (!ext2_check_descriptors (sb)) {
1002                 printk ("EXT2-fs: group descriptors corrupted!\n");
1003                 goto failed_mount2;
1004         }
1005         sbi->s_gdb_count = db_count;
1006         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1007         spin_lock_init(&sbi->s_next_gen_lock);
1008
1009         /* per fileystem reservation list head & lock */
1010         spin_lock_init(&sbi->s_rsv_window_lock);
1011         sbi->s_rsv_window_root = RB_ROOT;
1012         /*
1013          * Add a single, static dummy reservation to the start of the
1014          * reservation window list --- it gives us a placeholder for
1015          * append-at-start-of-list which makes the allocation logic
1016          * _much_ simpler.
1017          */
1018         sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1019         sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1020         sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1021         sbi->s_rsv_window_head.rsv_goal_size = 0;
1022         ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1023
1024         err = percpu_counter_init(&sbi->s_freeblocks_counter,
1025                                 ext2_count_free_blocks(sb));
1026         if (!err) {
1027                 err = percpu_counter_init(&sbi->s_freeinodes_counter,
1028                                 ext2_count_free_inodes(sb));
1029         }
1030         if (!err) {
1031                 err = percpu_counter_init(&sbi->s_dirs_counter,
1032                                 ext2_count_dirs(sb));
1033         }
1034         if (err) {
1035                 printk(KERN_ERR "EXT2-fs: insufficient memory\n");
1036                 goto failed_mount3;
1037         }
1038         /*
1039          * set up enough so that it can read an inode
1040          */
1041         sb->s_op = &ext2_sops;
1042         sb->s_export_op = &ext2_export_ops;
1043         sb->s_xattr = ext2_xattr_handlers;
1044         root = ext2_iget(sb, EXT2_ROOT_INO);
1045         if (IS_ERR(root)) {
1046                 ret = PTR_ERR(root);
1047                 goto failed_mount3;
1048         }
1049         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1050                 iput(root);
1051                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
1052                 goto failed_mount3;
1053         }
1054
1055         sb->s_root = d_alloc_root(root);
1056         if (!sb->s_root) {
1057                 iput(root);
1058                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
1059                 ret = -ENOMEM;
1060                 goto failed_mount3;
1061         }
1062         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1063                 ext2_warning(sb, __func__,
1064                         "mounting ext3 filesystem as ext2");
1065         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
1066         return 0;
1067
1068 cantfind_ext2:
1069         if (!silent)
1070                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
1071                        sb->s_id);
1072         goto failed_mount;
1073 failed_mount3:
1074         percpu_counter_destroy(&sbi->s_freeblocks_counter);
1075         percpu_counter_destroy(&sbi->s_freeinodes_counter);
1076         percpu_counter_destroy(&sbi->s_dirs_counter);
1077 failed_mount2:
1078         for (i = 0; i < db_count; i++)
1079                 brelse(sbi->s_group_desc[i]);
1080 failed_mount_group_desc:
1081         kfree(sbi->s_group_desc);
1082         kfree(sbi->s_debts);
1083 failed_mount:
1084         brelse(bh);
1085 failed_sbi:
1086         sb->s_fs_info = NULL;
1087         kfree(sbi->s_blockgroup_lock);
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 static int ext2_sync_fs(struct super_block *sb, int wait)
1122 {
1123         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1124
1125         lock_kernel();
1126         if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1127                 ext2_debug("setting valid to 0\n");
1128                 es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1129                 es->s_free_blocks_count =
1130                         cpu_to_le32(ext2_count_free_blocks(sb));
1131                 es->s_free_inodes_count =
1132                         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         return 0;
1142 }
1143
1144
1145 void ext2_write_super(struct super_block *sb)
1146 {
1147         if (!(sb->s_flags & MS_RDONLY))
1148                 ext2_sync_fs(sb, 1);
1149         else
1150                 sb->s_dirt = 0;
1151 }
1152
1153 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1154 {
1155         struct ext2_sb_info * sbi = EXT2_SB(sb);
1156         struct ext2_super_block * es;
1157         unsigned long old_mount_opt = sbi->s_mount_opt;
1158         struct ext2_mount_options old_opts;
1159         unsigned long old_sb_flags;
1160         int err;
1161
1162         lock_kernel();
1163
1164         /* Store the old options */
1165         old_sb_flags = sb->s_flags;
1166         old_opts.s_mount_opt = sbi->s_mount_opt;
1167         old_opts.s_resuid = sbi->s_resuid;
1168         old_opts.s_resgid = sbi->s_resgid;
1169
1170         /*
1171          * Allow the "check" option to be passed as a remount option.
1172          */
1173         if (!parse_options (data, sbi)) {
1174                 err = -EINVAL;
1175                 goto restore_opts;
1176         }
1177
1178         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1179                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1180
1181         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1182                                     EXT2_MOUNT_XIP if not */
1183
1184         if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1185                 printk("XIP: Unsupported blocksize\n");
1186                 err = -EINVAL;
1187                 goto restore_opts;
1188         }
1189
1190         es = sbi->s_es;
1191         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1192             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1193             invalidate_inodes(sb)) {
1194                 ext2_warning(sb, __func__, "refusing change of xip flag "
1195                              "with busy inodes while remounting");
1196                 sbi->s_mount_opt &= ~EXT2_MOUNT_XIP;
1197                 sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;
1198         }
1199         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
1200                 unlock_kernel();
1201                 return 0;
1202         }
1203         if (*flags & MS_RDONLY) {
1204                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1205                     !(sbi->s_mount_state & EXT2_VALID_FS)) {
1206                         unlock_kernel();
1207                         return 0;
1208                 }
1209                 /*
1210                  * OK, we are remounting a valid rw partition rdonly, so set
1211                  * the rdonly flag and then mark the partition as valid again.
1212                  */
1213                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1214                 es->s_mtime = cpu_to_le32(get_seconds());
1215         } else {
1216                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1217                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1218                 if (ret) {
1219                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1220                                "unsupported optional features (%x).\n",
1221                                sb->s_id, le32_to_cpu(ret));
1222                         err = -EROFS;
1223                         goto restore_opts;
1224                 }
1225                 /*
1226                  * Mounting a RDONLY partition read-write, so reread and
1227                  * store the current valid flag.  (It may have been changed
1228                  * by e2fsck since we originally mounted the partition.)
1229                  */
1230                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1231                 if (!ext2_setup_super (sb, es, 0))
1232                         sb->s_flags &= ~MS_RDONLY;
1233         }
1234         ext2_sync_super(sb, es);
1235         unlock_kernel();
1236         return 0;
1237 restore_opts:
1238         sbi->s_mount_opt = old_opts.s_mount_opt;
1239         sbi->s_resuid = old_opts.s_resuid;
1240         sbi->s_resgid = old_opts.s_resgid;
1241         sb->s_flags = old_sb_flags;
1242         unlock_kernel();
1243         return err;
1244 }
1245
1246 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1247 {
1248         struct super_block *sb = dentry->d_sb;
1249         struct ext2_sb_info *sbi = EXT2_SB(sb);
1250         struct ext2_super_block *es = sbi->s_es;
1251         u64 fsid;
1252
1253         if (test_opt (sb, MINIX_DF))
1254                 sbi->s_overhead_last = 0;
1255         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1256                 unsigned long i, overhead = 0;
1257                 smp_rmb();
1258
1259                 /*
1260                  * Compute the overhead (FS structures). This is constant
1261                  * for a given filesystem unless the number of block groups
1262                  * changes so we cache the previous value until it does.
1263                  */
1264
1265                 /*
1266                  * All of the blocks before first_data_block are
1267                  * overhead
1268                  */
1269                 overhead = le32_to_cpu(es->s_first_data_block);
1270
1271                 /*
1272                  * Add the overhead attributed to the superblock and
1273                  * block group descriptors.  If the sparse superblocks
1274                  * feature is turned on, then not all groups have this.
1275                  */
1276                 for (i = 0; i < sbi->s_groups_count; i++)
1277                         overhead += ext2_bg_has_super(sb, i) +
1278                                 ext2_bg_num_gdb(sb, i);
1279
1280                 /*
1281                  * Every block group has an inode bitmap, a block
1282                  * bitmap, and an inode table.
1283                  */
1284                 overhead += (sbi->s_groups_count *
1285                              (2 + sbi->s_itb_per_group));
1286                 sbi->s_overhead_last = overhead;
1287                 smp_wmb();
1288                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1289         }
1290
1291         buf->f_type = EXT2_SUPER_MAGIC;
1292         buf->f_bsize = sb->s_blocksize;
1293         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1294         buf->f_bfree = ext2_count_free_blocks(sb);
1295         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1296         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1297         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1298                 buf->f_bavail = 0;
1299         buf->f_files = le32_to_cpu(es->s_inodes_count);
1300         buf->f_ffree = ext2_count_free_inodes(sb);
1301         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1302         buf->f_namelen = EXT2_NAME_LEN;
1303         fsid = le64_to_cpup((void *)es->s_uuid) ^
1304                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1305         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1306         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1307         return 0;
1308 }
1309
1310 static int ext2_get_sb(struct file_system_type *fs_type,
1311         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1312 {
1313         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1314 }
1315
1316 #ifdef CONFIG_QUOTA
1317
1318 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1319  * acquiring the locks... As quota files are never truncated and quota code
1320  * itself serializes the operations (and noone else should touch the files)
1321  * we don't have to be afraid of races */
1322 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1323                                size_t len, loff_t off)
1324 {
1325         struct inode *inode = sb_dqopt(sb)->files[type];
1326         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1327         int err = 0;
1328         int offset = off & (sb->s_blocksize - 1);
1329         int tocopy;
1330         size_t toread;
1331         struct buffer_head tmp_bh;
1332         struct buffer_head *bh;
1333         loff_t i_size = i_size_read(inode);
1334
1335         if (off > i_size)
1336                 return 0;
1337         if (off+len > i_size)
1338                 len = i_size-off;
1339         toread = len;
1340         while (toread > 0) {
1341                 tocopy = sb->s_blocksize - offset < toread ?
1342                                 sb->s_blocksize - offset : toread;
1343
1344                 tmp_bh.b_state = 0;
1345                 tmp_bh.b_size = sb->s_blocksize;
1346                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1347                 if (err < 0)
1348                         return err;
1349                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1350                         memset(data, 0, tocopy);
1351                 else {
1352                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1353                         if (!bh)
1354                                 return -EIO;
1355                         memcpy(data, bh->b_data+offset, tocopy);
1356                         brelse(bh);
1357                 }
1358                 offset = 0;
1359                 toread -= tocopy;
1360                 data += tocopy;
1361                 blk++;
1362         }
1363         return len;
1364 }
1365
1366 /* Write to quotafile */
1367 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1368                                 const char *data, size_t len, loff_t off)
1369 {
1370         struct inode *inode = sb_dqopt(sb)->files[type];
1371         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1372         int err = 0;
1373         int offset = off & (sb->s_blocksize - 1);
1374         int tocopy;
1375         size_t towrite = len;
1376         struct buffer_head tmp_bh;
1377         struct buffer_head *bh;
1378
1379         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1380         while (towrite > 0) {
1381                 tocopy = sb->s_blocksize - offset < towrite ?
1382                                 sb->s_blocksize - offset : towrite;
1383
1384                 tmp_bh.b_state = 0;
1385                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1386                 if (err < 0)
1387                         goto out;
1388                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1389                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1390                 else
1391                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1392                 if (!bh) {
1393                         err = -EIO;
1394                         goto out;
1395                 }
1396                 lock_buffer(bh);
1397                 memcpy(bh->b_data+offset, data, tocopy);
1398                 flush_dcache_page(bh->b_page);
1399                 set_buffer_uptodate(bh);
1400                 mark_buffer_dirty(bh);
1401                 unlock_buffer(bh);
1402                 brelse(bh);
1403                 offset = 0;
1404                 towrite -= tocopy;
1405                 data += tocopy;
1406                 blk++;
1407         }
1408 out:
1409         if (len == towrite) {
1410                 mutex_unlock(&inode->i_mutex);
1411                 return err;
1412         }
1413         if (inode->i_size < off+len-towrite)
1414                 i_size_write(inode, off+len-towrite);
1415         inode->i_version++;
1416         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1417         mark_inode_dirty(inode);
1418         mutex_unlock(&inode->i_mutex);
1419         return len - towrite;
1420 }
1421
1422 #endif
1423
1424 static struct file_system_type ext2_fs_type = {
1425         .owner          = THIS_MODULE,
1426         .name           = "ext2",
1427         .get_sb         = ext2_get_sb,
1428         .kill_sb        = kill_block_super,
1429         .fs_flags       = FS_REQUIRES_DEV,
1430 };
1431
1432 static int __init init_ext2_fs(void)
1433 {
1434         int err = init_ext2_xattr();
1435         if (err)
1436                 return err;
1437         err = init_inodecache();
1438         if (err)
1439                 goto out1;
1440         err = register_filesystem(&ext2_fs_type);
1441         if (err)
1442                 goto out;
1443         return 0;
1444 out:
1445         destroy_inodecache();
1446 out1:
1447         exit_ext2_xattr();
1448         return err;
1449 }
1450
1451 static void __exit exit_ext2_fs(void)
1452 {
1453         unregister_filesystem(&ext2_fs_type);
1454         destroy_inodecache();
1455         exit_ext2_xattr();
1456 }
1457
1458 module_init(init_ext2_fs)
1459 module_exit(exit_ext2_fs)