Merge master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6
[linux-2.6] / 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/smp_lock.h>
29 #include <linux/vfs.h>
30 #include <linux/seq_file.h>
31 #include <linux/mount.h>
32 #include <asm/uaccess.h>
33 #include "ext2.h"
34 #include "xattr.h"
35 #include "acl.h"
36 #include "xip.h"
37
38 static void ext2_sync_super(struct super_block *sb,
39                             struct ext2_super_block *es);
40 static int ext2_remount (struct super_block * sb, int * flags, char * data);
41 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
42
43 void ext2_error (struct super_block * sb, const char * function,
44                  const char * fmt, ...)
45 {
46         va_list args;
47         struct ext2_sb_info *sbi = EXT2_SB(sb);
48         struct ext2_super_block *es = sbi->s_es;
49
50         if (!(sb->s_flags & MS_RDONLY)) {
51                 sbi->s_mount_state |= EXT2_ERROR_FS;
52                 es->s_state =
53                         cpu_to_le16(le16_to_cpu(es->s_state) | EXT2_ERROR_FS);
54                 ext2_sync_super(sb, es);
55         }
56
57         va_start(args, fmt);
58         printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
59         vprintk(fmt, args);
60         printk("\n");
61         va_end(args);
62
63         if (test_opt(sb, ERRORS_PANIC))
64                 panic("EXT2-fs panic from previous error\n");
65         if (test_opt(sb, ERRORS_RO)) {
66                 printk("Remounting filesystem read-only\n");
67                 sb->s_flags |= MS_RDONLY;
68         }
69 }
70
71 void ext2_warning (struct super_block * sb, const char * function,
72                    const char * fmt, ...)
73 {
74         va_list args;
75
76         va_start(args, fmt);
77         printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
78                sb->s_id, function);
79         vprintk(fmt, args);
80         printk("\n");
81         va_end(args);
82 }
83
84 void ext2_update_dynamic_rev(struct super_block *sb)
85 {
86         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
87
88         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
89                 return;
90
91         ext2_warning(sb, __FUNCTION__,
92                      "updating to rev %d because of new feature flag, "
93                      "running e2fsck is recommended",
94                      EXT2_DYNAMIC_REV);
95
96         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
97         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
98         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
99         /* leave es->s_feature_*compat flags alone */
100         /* es->s_uuid will be set by e2fsck if empty */
101
102         /*
103          * The rest of the superblock fields should be zero, and if not it
104          * means they are likely already in use, so leave them alone.  We
105          * can leave it up to e2fsck to clean up any inconsistencies there.
106          */
107 }
108
109 static void ext2_put_super (struct super_block * sb)
110 {
111         int db_count;
112         int i;
113         struct ext2_sb_info *sbi = EXT2_SB(sb);
114
115         ext2_xattr_put_super(sb);
116         if (!(sb->s_flags & MS_RDONLY)) {
117                 struct ext2_super_block *es = sbi->s_es;
118
119                 es->s_state = cpu_to_le16(sbi->s_mount_state);
120                 ext2_sync_super(sb, es);
121         }
122         db_count = sbi->s_gdb_count;
123         for (i = 0; i < db_count; i++)
124                 if (sbi->s_group_desc[i])
125                         brelse (sbi->s_group_desc[i]);
126         kfree(sbi->s_group_desc);
127         kfree(sbi->s_debts);
128         percpu_counter_destroy(&sbi->s_freeblocks_counter);
129         percpu_counter_destroy(&sbi->s_freeinodes_counter);
130         percpu_counter_destroy(&sbi->s_dirs_counter);
131         brelse (sbi->s_sbh);
132         sb->s_fs_info = NULL;
133         kfree(sbi);
134
135         return;
136 }
137
138 static kmem_cache_t * ext2_inode_cachep;
139
140 static struct inode *ext2_alloc_inode(struct super_block *sb)
141 {
142         struct ext2_inode_info *ei;
143         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, SLAB_KERNEL);
144         if (!ei)
145                 return NULL;
146 #ifdef CONFIG_EXT2_FS_POSIX_ACL
147         ei->i_acl = EXT2_ACL_NOT_CACHED;
148         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
149 #endif
150         ei->vfs_inode.i_version = 1;
151         return &ei->vfs_inode;
152 }
153
154 static void ext2_destroy_inode(struct inode *inode)
155 {
156         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
157 }
158
159 static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
160 {
161         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
162
163         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
164             SLAB_CTOR_CONSTRUCTOR) {
165                 rwlock_init(&ei->i_meta_lock);
166 #ifdef CONFIG_EXT2_FS_XATTR
167                 init_rwsem(&ei->xattr_sem);
168 #endif
169                 inode_init_once(&ei->vfs_inode);
170         }
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, NULL);
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 #ifdef CONFIG_EXT2_FS_POSIX_ACL
193         struct ext2_inode_info *ei = EXT2_I(inode);
194
195         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
196                 posix_acl_release(ei->i_acl);
197                 ei->i_acl = EXT2_ACL_NOT_CACHED;
198         }
199         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
200                 posix_acl_release(ei->i_default_acl);
201                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
202         }
203 #endif
204 }
205
206 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
207 {
208         struct ext2_sb_info *sbi = EXT2_SB(vfs->mnt_sb);
209
210         if (sbi->s_mount_opt & EXT2_MOUNT_GRPID)
211                 seq_puts(seq, ",grpid");
212
213 #if defined(CONFIG_QUOTA)
214         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
215                 seq_puts(seq, ",usrquota");
216
217         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
218                 seq_puts(seq, ",grpquota");
219 #endif
220
221 #if defined(CONFIG_EXT2_FS_XIP)
222         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
223                 seq_puts(seq, ",xip");
224 #endif
225
226         return 0;
227 }
228
229 #ifdef CONFIG_QUOTA
230 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
231 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
232 #endif
233
234 static struct super_operations ext2_sops = {
235         .alloc_inode    = ext2_alloc_inode,
236         .destroy_inode  = ext2_destroy_inode,
237         .read_inode     = ext2_read_inode,
238         .write_inode    = ext2_write_inode,
239         .put_inode      = ext2_put_inode,
240         .delete_inode   = ext2_delete_inode,
241         .put_super      = ext2_put_super,
242         .write_super    = ext2_write_super,
243         .statfs         = ext2_statfs,
244         .remount_fs     = ext2_remount,
245         .clear_inode    = ext2_clear_inode,
246         .show_options   = ext2_show_options,
247 #ifdef CONFIG_QUOTA
248         .quota_read     = ext2_quota_read,
249         .quota_write    = ext2_quota_write,
250 #endif
251 };
252
253 static struct dentry *ext2_get_dentry(struct super_block *sb, void *vobjp)
254 {
255         __u32 *objp = vobjp;
256         unsigned long ino = objp[0];
257         __u32 generation = objp[1];
258         struct inode *inode;
259         struct dentry *result;
260
261         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
262                 return ERR_PTR(-ESTALE);
263         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
264                 return ERR_PTR(-ESTALE);
265
266         /* iget isn't really right if the inode is currently unallocated!!
267          * ext2_read_inode currently does appropriate checks, but
268          * it might be "neater" to call ext2_get_inode first and check
269          * if the inode is valid.....
270          */
271         inode = iget(sb, ino);
272         if (inode == NULL)
273                 return ERR_PTR(-ENOMEM);
274         if (is_bad_inode(inode) ||
275             (generation && inode->i_generation != generation)) {
276                 /* we didn't find the right inode.. */
277                 iput(inode);
278                 return ERR_PTR(-ESTALE);
279         }
280         /* now to find a dentry.
281          * If possible, get a well-connected one
282          */
283         result = d_alloc_anon(inode);
284         if (!result) {
285                 iput(inode);
286                 return ERR_PTR(-ENOMEM);
287         }
288         return result;
289 }
290
291 /* Yes, most of these are left as NULL!!
292  * A NULL value implies the default, which works with ext2-like file
293  * systems, but can be improved upon.
294  * Currently only get_parent is required.
295  */
296 static struct export_operations ext2_export_ops = {
297         .get_parent = ext2_get_parent,
298         .get_dentry = ext2_get_dentry,
299 };
300
301 static unsigned long get_sb_block(void **data)
302 {
303         unsigned long   sb_block;
304         char            *options = (char *) *data;
305
306         if (!options || strncmp(options, "sb=", 3) != 0)
307                 return 1;       /* Default location */
308         options += 3;
309         sb_block = simple_strtoul(options, &options, 0);
310         if (*options && *options != ',') {
311                 printk("EXT2-fs: Invalid sb specification: %s\n",
312                        (char *) *data);
313                 return 1;
314         }
315         if (*options == ',')
316                 options++;
317         *data = (void *) options;
318         return sb_block;
319 }
320
321 enum {
322         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
323         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
324         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
325         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
326         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
327         Opt_usrquota, Opt_grpquota
328 };
329
330 static match_table_t tokens = {
331         {Opt_bsd_df, "bsddf"},
332         {Opt_minix_df, "minixdf"},
333         {Opt_grpid, "grpid"},
334         {Opt_grpid, "bsdgroups"},
335         {Opt_nogrpid, "nogrpid"},
336         {Opt_nogrpid, "sysvgroups"},
337         {Opt_resgid, "resgid=%u"},
338         {Opt_resuid, "resuid=%u"},
339         {Opt_sb, "sb=%u"},
340         {Opt_err_cont, "errors=continue"},
341         {Opt_err_panic, "errors=panic"},
342         {Opt_err_ro, "errors=remount-ro"},
343         {Opt_nouid32, "nouid32"},
344         {Opt_nocheck, "check=none"},
345         {Opt_nocheck, "nocheck"},
346         {Opt_debug, "debug"},
347         {Opt_oldalloc, "oldalloc"},
348         {Opt_orlov, "orlov"},
349         {Opt_nobh, "nobh"},
350         {Opt_user_xattr, "user_xattr"},
351         {Opt_nouser_xattr, "nouser_xattr"},
352         {Opt_acl, "acl"},
353         {Opt_noacl, "noacl"},
354         {Opt_xip, "xip"},
355         {Opt_grpquota, "grpquota"},
356         {Opt_ignore, "noquota"},
357         {Opt_quota, "quota"},
358         {Opt_usrquota, "usrquota"},
359         {Opt_err, NULL}
360 };
361
362 static int parse_options (char * options,
363                           struct ext2_sb_info *sbi)
364 {
365         char * p;
366         substring_t args[MAX_OPT_ARGS];
367         unsigned long kind = EXT2_MOUNT_ERRORS_CONT;
368         int option;
369
370         if (!options)
371                 return 1;
372
373         while ((p = strsep (&options, ",")) != NULL) {
374                 int token;
375                 if (!*p)
376                         continue;
377
378                 token = match_token(p, tokens, args);
379                 switch (token) {
380                 case Opt_bsd_df:
381                         clear_opt (sbi->s_mount_opt, MINIX_DF);
382                         break;
383                 case Opt_minix_df:
384                         set_opt (sbi->s_mount_opt, MINIX_DF);
385                         break;
386                 case Opt_grpid:
387                         set_opt (sbi->s_mount_opt, GRPID);
388                         break;
389                 case Opt_nogrpid:
390                         clear_opt (sbi->s_mount_opt, GRPID);
391                         break;
392                 case Opt_resuid:
393                         if (match_int(&args[0], &option))
394                                 return 0;
395                         sbi->s_resuid = option;
396                         break;
397                 case Opt_resgid:
398                         if (match_int(&args[0], &option))
399                                 return 0;
400                         sbi->s_resgid = option;
401                         break;
402                 case Opt_sb:
403                         /* handled by get_sb_block() instead of here */
404                         /* *sb_block = match_int(&args[0]); */
405                         break;
406                 case Opt_err_panic:
407                         kind = EXT2_MOUNT_ERRORS_PANIC;
408                         break;
409                 case Opt_err_ro:
410                         kind = EXT2_MOUNT_ERRORS_RO;
411                         break;
412                 case Opt_err_cont:
413                         kind = EXT2_MOUNT_ERRORS_CONT;
414                         break;
415                 case Opt_nouid32:
416                         set_opt (sbi->s_mount_opt, NO_UID32);
417                         break;
418                 case Opt_nocheck:
419                         clear_opt (sbi->s_mount_opt, CHECK);
420                         break;
421                 case Opt_debug:
422                         set_opt (sbi->s_mount_opt, DEBUG);
423                         break;
424                 case Opt_oldalloc:
425                         set_opt (sbi->s_mount_opt, OLDALLOC);
426                         break;
427                 case Opt_orlov:
428                         clear_opt (sbi->s_mount_opt, OLDALLOC);
429                         break;
430                 case Opt_nobh:
431                         set_opt (sbi->s_mount_opt, NOBH);
432                         break;
433 #ifdef CONFIG_EXT2_FS_XATTR
434                 case Opt_user_xattr:
435                         set_opt (sbi->s_mount_opt, XATTR_USER);
436                         break;
437                 case Opt_nouser_xattr:
438                         clear_opt (sbi->s_mount_opt, XATTR_USER);
439                         break;
440 #else
441                 case Opt_user_xattr:
442                 case Opt_nouser_xattr:
443                         printk("EXT2 (no)user_xattr options not supported\n");
444                         break;
445 #endif
446 #ifdef CONFIG_EXT2_FS_POSIX_ACL
447                 case Opt_acl:
448                         set_opt(sbi->s_mount_opt, POSIX_ACL);
449                         break;
450                 case Opt_noacl:
451                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
452                         break;
453 #else
454                 case Opt_acl:
455                 case Opt_noacl:
456                         printk("EXT2 (no)acl options not supported\n");
457                         break;
458 #endif
459                 case Opt_xip:
460 #ifdef CONFIG_EXT2_FS_XIP
461                         set_opt (sbi->s_mount_opt, XIP);
462 #else
463                         printk("EXT2 xip option not supported\n");
464 #endif
465                         break;
466
467 #if defined(CONFIG_QUOTA)
468                 case Opt_quota:
469                 case Opt_usrquota:
470                         set_opt(sbi->s_mount_opt, USRQUOTA);
471                         break;
472
473                 case Opt_grpquota:
474                         set_opt(sbi->s_mount_opt, GRPQUOTA);
475                         break;
476 #else
477                 case Opt_quota:
478                 case Opt_usrquota:
479                 case Opt_grpquota:
480                         printk(KERN_ERR
481                                 "EXT2-fs: quota operations not supported.\n");
482
483                         break;
484 #endif
485
486                 case Opt_ignore:
487                         break;
488                 default:
489                         return 0;
490                 }
491         }
492         sbi->s_mount_opt |= kind;
493         return 1;
494 }
495
496 static int ext2_setup_super (struct super_block * sb,
497                               struct ext2_super_block * es,
498                               int read_only)
499 {
500         int res = 0;
501         struct ext2_sb_info *sbi = EXT2_SB(sb);
502
503         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
504                 printk ("EXT2-fs warning: revision level too high, "
505                         "forcing read-only mode\n");
506                 res = MS_RDONLY;
507         }
508         if (read_only)
509                 return res;
510         if (!(sbi->s_mount_state & EXT2_VALID_FS))
511                 printk ("EXT2-fs warning: mounting unchecked fs, "
512                         "running e2fsck is recommended\n");
513         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
514                 printk ("EXT2-fs warning: mounting fs with errors, "
515                         "running e2fsck is recommended\n");
516         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
517                  le16_to_cpu(es->s_mnt_count) >=
518                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
519                 printk ("EXT2-fs warning: maximal mount count reached, "
520                         "running e2fsck is recommended\n");
521         else if (le32_to_cpu(es->s_checkinterval) &&
522                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
523                 printk ("EXT2-fs warning: checktime reached, "
524                         "running e2fsck is recommended\n");
525         if (!le16_to_cpu(es->s_max_mnt_count))
526                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
527         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
528         ext2_write_super(sb);
529         if (test_opt (sb, DEBUG))
530                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
531                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
532                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
533                         sbi->s_frag_size,
534                         sbi->s_groups_count,
535                         EXT2_BLOCKS_PER_GROUP(sb),
536                         EXT2_INODES_PER_GROUP(sb),
537                         sbi->s_mount_opt);
538         return res;
539 }
540
541 static int ext2_check_descriptors (struct super_block * sb)
542 {
543         int i;
544         int desc_block = 0;
545         struct ext2_sb_info *sbi = EXT2_SB(sb);
546         unsigned long first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
547         unsigned long last_block;
548         struct ext2_group_desc * gdp = NULL;
549
550         ext2_debug ("Checking group descriptors");
551
552         for (i = 0; i < sbi->s_groups_count; i++)
553         {
554                 if (i == sbi->s_groups_count - 1)
555                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
556                 else
557                         last_block = first_block +
558                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
559
560                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
561                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
562                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
563                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
564                 {
565                         ext2_error (sb, "ext2_check_descriptors",
566                                     "Block bitmap for group %d"
567                                     " not in group (block %lu)!",
568                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
569                         return 0;
570                 }
571                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
572                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
573                 {
574                         ext2_error (sb, "ext2_check_descriptors",
575                                     "Inode bitmap for group %d"
576                                     " not in group (block %lu)!",
577                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
578                         return 0;
579                 }
580                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
581                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >
582                     last_block)
583                 {
584                         ext2_error (sb, "ext2_check_descriptors",
585                                     "Inode table for group %d"
586                                     " not in group (block %lu)!",
587                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
588                         return 0;
589                 }
590                 first_block += EXT2_BLOCKS_PER_GROUP(sb);
591                 gdp++;
592         }
593         return 1;
594 }
595
596 #define log2(n) ffz(~(n))
597  
598 /*
599  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
600  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
601  * We need to be 1 filesystem block less than the 2^32 sector limit.
602  */
603 static loff_t ext2_max_size(int bits)
604 {
605         loff_t res = EXT2_NDIR_BLOCKS;
606         /* This constant is calculated to be the largest file size for a
607          * dense, 4k-blocksize file such that the total number of
608          * sectors in the file, including data and all indirect blocks,
609          * does not exceed 2^32. */
610         const loff_t upper_limit = 0x1ff7fffd000LL;
611
612         res += 1LL << (bits-2);
613         res += 1LL << (2*(bits-2));
614         res += 1LL << (3*(bits-2));
615         res <<= bits;
616         if (res > upper_limit)
617                 res = upper_limit;
618         return res;
619 }
620
621 static unsigned long descriptor_loc(struct super_block *sb,
622                                     unsigned long logic_sb_block,
623                                     int nr)
624 {
625         struct ext2_sb_info *sbi = EXT2_SB(sb);
626         unsigned long bg, first_data_block, first_meta_bg;
627         int has_super = 0;
628         
629         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
630         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
631
632         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
633             nr < first_meta_bg)
634                 return (logic_sb_block + nr + 1);
635         bg = sbi->s_desc_per_block * nr;
636         if (ext2_bg_has_super(sb, bg))
637                 has_super = 1;
638         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
639 }
640
641 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
642 {
643         struct buffer_head * bh;
644         struct ext2_sb_info * sbi;
645         struct ext2_super_block * es;
646         struct inode *root;
647         unsigned long block;
648         unsigned long sb_block = get_sb_block(&data);
649         unsigned long logic_sb_block;
650         unsigned long offset = 0;
651         unsigned long def_mount_opts;
652         int blocksize = BLOCK_SIZE;
653         int db_count;
654         int i, j;
655         __le32 features;
656
657         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
658         if (!sbi)
659                 return -ENOMEM;
660         sb->s_fs_info = sbi;
661
662         /*
663          * See what the current blocksize for the device is, and
664          * use that as the blocksize.  Otherwise (or if the blocksize
665          * is smaller than the default) use the default.
666          * This is important for devices that have a hardware
667          * sectorsize that is larger than the default.
668          */
669         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
670         if (!blocksize) {
671                 printk ("EXT2-fs: unable to set blocksize\n");
672                 goto failed_sbi;
673         }
674
675         /*
676          * If the superblock doesn't start on a hardware sector boundary,
677          * calculate the offset.  
678          */
679         if (blocksize != BLOCK_SIZE) {
680                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
681                 offset = (sb_block*BLOCK_SIZE) % blocksize;
682         } else {
683                 logic_sb_block = sb_block;
684         }
685
686         if (!(bh = sb_bread(sb, logic_sb_block))) {
687                 printk ("EXT2-fs: unable to read superblock\n");
688                 goto failed_sbi;
689         }
690         /*
691          * Note: s_es must be initialized as soon as possible because
692          *       some ext2 macro-instructions depend on its value
693          */
694         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
695         sbi->s_es = es;
696         sb->s_magic = le16_to_cpu(es->s_magic);
697
698         if (sb->s_magic != EXT2_SUPER_MAGIC)
699                 goto cantfind_ext2;
700
701         /* Set defaults before we parse the mount options */
702         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
703         if (def_mount_opts & EXT2_DEFM_DEBUG)
704                 set_opt(sbi->s_mount_opt, DEBUG);
705         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
706                 set_opt(sbi->s_mount_opt, GRPID);
707         if (def_mount_opts & EXT2_DEFM_UID16)
708                 set_opt(sbi->s_mount_opt, NO_UID32);
709         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
710                 set_opt(sbi->s_mount_opt, XATTR_USER);
711         if (def_mount_opts & EXT2_DEFM_ACL)
712                 set_opt(sbi->s_mount_opt, POSIX_ACL);
713         
714         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
715                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
716         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
717                 set_opt(sbi->s_mount_opt, ERRORS_RO);
718
719         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
720         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
721         
722         if (!parse_options ((char *) data, sbi))
723                 goto failed_mount;
724
725         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
726                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
727                  MS_POSIXACL : 0);
728
729         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
730                                     EXT2_MOUNT_XIP if not */
731
732         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
733             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
734              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
735              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
736                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
737                        "running e2fsck is recommended\n");
738         /*
739          * Check feature flags regardless of the revision level, since we
740          * previously didn't change the revision level when setting the flags,
741          * so there is a chance incompat flags are set on a rev 0 filesystem.
742          */
743         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
744         if (features) {
745                 printk("EXT2-fs: %s: couldn't mount because of "
746                        "unsupported optional features (%x).\n",
747                        sb->s_id, le32_to_cpu(features));
748                 goto failed_mount;
749         }
750         if (!(sb->s_flags & MS_RDONLY) &&
751             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
752                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
753                        "unsupported optional features (%x).\n",
754                        sb->s_id, le32_to_cpu(features));
755                 goto failed_mount;
756         }
757
758         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
759
760         if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
761                                   (sb->s_blocksize != blocksize))) {
762                 if (!silent)
763                         printk("XIP: Unsupported blocksize\n");
764                 goto failed_mount;
765         }
766
767         /* If the blocksize doesn't match, re-read the thing.. */
768         if (sb->s_blocksize != blocksize) {
769                 brelse(bh);
770
771                 if (!sb_set_blocksize(sb, blocksize)) {
772                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
773                         goto failed_sbi;
774                 }
775
776                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
777                 offset = (sb_block*BLOCK_SIZE) % blocksize;
778                 bh = sb_bread(sb, logic_sb_block);
779                 if(!bh) {
780                         printk("EXT2-fs: Couldn't read superblock on "
781                                "2nd try.\n");
782                         goto failed_sbi;
783                 }
784                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
785                 sbi->s_es = es;
786                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
787                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
788                         goto failed_mount;
789                 }
790         }
791
792         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
793
794         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
795                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
796                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
797         } else {
798                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
799                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
800                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
801                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
802                     (sbi->s_inode_size > blocksize)) {
803                         printk ("EXT2-fs: unsupported inode size: %d\n",
804                                 sbi->s_inode_size);
805                         goto failed_mount;
806                 }
807         }
808
809         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
810                                    le32_to_cpu(es->s_log_frag_size);
811         if (sbi->s_frag_size == 0)
812                 goto cantfind_ext2;
813         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
814
815         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
816         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
817         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
818
819         if (EXT2_INODE_SIZE(sb) == 0)
820                 goto cantfind_ext2;
821         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
822         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
823                 goto cantfind_ext2;
824         sbi->s_itb_per_group = sbi->s_inodes_per_group /
825                                         sbi->s_inodes_per_block;
826         sbi->s_desc_per_block = sb->s_blocksize /
827                                         sizeof (struct ext2_group_desc);
828         sbi->s_sbh = bh;
829         sbi->s_mount_state = le16_to_cpu(es->s_state);
830         sbi->s_addr_per_block_bits =
831                 log2 (EXT2_ADDR_PER_BLOCK(sb));
832         sbi->s_desc_per_block_bits =
833                 log2 (EXT2_DESC_PER_BLOCK(sb));
834
835         if (sb->s_magic != EXT2_SUPER_MAGIC)
836                 goto cantfind_ext2;
837
838         if (sb->s_blocksize != bh->b_size) {
839                 if (!silent)
840                         printk ("VFS: Unsupported blocksize on dev "
841                                 "%s.\n", sb->s_id);
842                 goto failed_mount;
843         }
844
845         if (sb->s_blocksize != sbi->s_frag_size) {
846                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
847                         sbi->s_frag_size, sb->s_blocksize);
848                 goto failed_mount;
849         }
850
851         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
852                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
853                         sbi->s_blocks_per_group);
854                 goto failed_mount;
855         }
856         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
857                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
858                         sbi->s_frags_per_group);
859                 goto failed_mount;
860         }
861         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
862                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
863                         sbi->s_inodes_per_group);
864                 goto failed_mount;
865         }
866
867         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
868                 goto cantfind_ext2;
869         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
870                                 le32_to_cpu(es->s_first_data_block) - 1)
871                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
872         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
873                    EXT2_DESC_PER_BLOCK(sb);
874         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
875         if (sbi->s_group_desc == NULL) {
876                 printk ("EXT2-fs: not enough memory\n");
877                 goto failed_mount;
878         }
879         bgl_lock_init(&sbi->s_blockgroup_lock);
880         sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
881                                GFP_KERNEL);
882         if (!sbi->s_debts) {
883                 printk ("EXT2-fs: not enough memory\n");
884                 goto failed_mount_group_desc;
885         }
886         memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
887         for (i = 0; i < db_count; i++) {
888                 block = descriptor_loc(sb, logic_sb_block, i);
889                 sbi->s_group_desc[i] = sb_bread(sb, block);
890                 if (!sbi->s_group_desc[i]) {
891                         for (j = 0; j < i; j++)
892                                 brelse (sbi->s_group_desc[j]);
893                         printk ("EXT2-fs: unable to read group descriptors\n");
894                         goto failed_mount_group_desc;
895                 }
896         }
897         if (!ext2_check_descriptors (sb)) {
898                 printk ("EXT2-fs: group descriptors corrupted!\n");
899                 goto failed_mount2;
900         }
901         sbi->s_gdb_count = db_count;
902         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
903         spin_lock_init(&sbi->s_next_gen_lock);
904
905         percpu_counter_init(&sbi->s_freeblocks_counter,
906                                 ext2_count_free_blocks(sb));
907         percpu_counter_init(&sbi->s_freeinodes_counter,
908                                 ext2_count_free_inodes(sb));
909         percpu_counter_init(&sbi->s_dirs_counter,
910                                 ext2_count_dirs(sb));
911         /*
912          * set up enough so that it can read an inode
913          */
914         sb->s_op = &ext2_sops;
915         sb->s_export_op = &ext2_export_ops;
916         sb->s_xattr = ext2_xattr_handlers;
917         root = iget(sb, EXT2_ROOT_INO);
918         sb->s_root = d_alloc_root(root);
919         if (!sb->s_root) {
920                 iput(root);
921                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
922                 goto failed_mount3;
923         }
924         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
925                 dput(sb->s_root);
926                 sb->s_root = NULL;
927                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
928                 goto failed_mount3;
929         }
930         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
931                 ext2_warning(sb, __FUNCTION__,
932                         "mounting ext3 filesystem as ext2");
933         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
934         return 0;
935
936 cantfind_ext2:
937         if (!silent)
938                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
939                        sb->s_id);
940         goto failed_mount;
941 failed_mount3:
942         percpu_counter_destroy(&sbi->s_freeblocks_counter);
943         percpu_counter_destroy(&sbi->s_freeinodes_counter);
944         percpu_counter_destroy(&sbi->s_dirs_counter);
945 failed_mount2:
946         for (i = 0; i < db_count; i++)
947                 brelse(sbi->s_group_desc[i]);
948 failed_mount_group_desc:
949         kfree(sbi->s_group_desc);
950         kfree(sbi->s_debts);
951 failed_mount:
952         brelse(bh);
953 failed_sbi:
954         sb->s_fs_info = NULL;
955         kfree(sbi);
956         return -EINVAL;
957 }
958
959 static void ext2_commit_super (struct super_block * sb,
960                                struct ext2_super_block * es)
961 {
962         es->s_wtime = cpu_to_le32(get_seconds());
963         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
964         sb->s_dirt = 0;
965 }
966
967 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
968 {
969         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
970         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
971         es->s_wtime = cpu_to_le32(get_seconds());
972         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
973         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
974         sb->s_dirt = 0;
975 }
976
977 /*
978  * In the second extended file system, it is not necessary to
979  * write the super block since we use a mapping of the
980  * disk super block in a buffer.
981  *
982  * However, this function is still used to set the fs valid
983  * flags to 0.  We need to set this flag to 0 since the fs
984  * may have been checked while mounted and e2fsck may have
985  * set s_state to EXT2_VALID_FS after some corrections.
986  */
987
988 void ext2_write_super (struct super_block * sb)
989 {
990         struct ext2_super_block * es;
991         lock_kernel();
992         if (!(sb->s_flags & MS_RDONLY)) {
993                 es = EXT2_SB(sb)->s_es;
994
995                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
996                         ext2_debug ("setting valid to 0\n");
997                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
998                                                   ~EXT2_VALID_FS);
999                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1000                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1001                         es->s_mtime = cpu_to_le32(get_seconds());
1002                         ext2_sync_super(sb, es);
1003                 } else
1004                         ext2_commit_super (sb, es);
1005         }
1006         sb->s_dirt = 0;
1007         unlock_kernel();
1008 }
1009
1010 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1011 {
1012         struct ext2_sb_info * sbi = EXT2_SB(sb);
1013         struct ext2_super_block * es;
1014         unsigned long old_mount_opt = sbi->s_mount_opt;
1015         struct ext2_mount_options old_opts;
1016         unsigned long old_sb_flags;
1017         int err;
1018
1019         /* Store the old options */
1020         old_sb_flags = sb->s_flags;
1021         old_opts.s_mount_opt = sbi->s_mount_opt;
1022         old_opts.s_resuid = sbi->s_resuid;
1023         old_opts.s_resgid = sbi->s_resgid;
1024
1025         /*
1026          * Allow the "check" option to be passed as a remount option.
1027          */
1028         if (!parse_options (data, sbi)) {
1029                 err = -EINVAL;
1030                 goto restore_opts;
1031         }
1032
1033         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1034                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1035
1036         es = sbi->s_es;
1037         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1038             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1039             invalidate_inodes(sb))
1040                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1041                              "xip remain in cache (no functional problem)");
1042         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1043                 return 0;
1044         if (*flags & MS_RDONLY) {
1045                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1046                     !(sbi->s_mount_state & EXT2_VALID_FS))
1047                         return 0;
1048                 /*
1049                  * OK, we are remounting a valid rw partition rdonly, so set
1050                  * the rdonly flag and then mark the partition as valid again.
1051                  */
1052                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1053                 es->s_mtime = cpu_to_le32(get_seconds());
1054         } else {
1055                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1056                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1057                 if (ret) {
1058                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1059                                "unsupported optional features (%x).\n",
1060                                sb->s_id, le32_to_cpu(ret));
1061                         err = -EROFS;
1062                         goto restore_opts;
1063                 }
1064                 /*
1065                  * Mounting a RDONLY partition read-write, so reread and
1066                  * store the current valid flag.  (It may have been changed
1067                  * by e2fsck since we originally mounted the partition.)
1068                  */
1069                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1070                 if (!ext2_setup_super (sb, es, 0))
1071                         sb->s_flags &= ~MS_RDONLY;
1072         }
1073         ext2_sync_super(sb, es);
1074         return 0;
1075 restore_opts:
1076         sbi->s_mount_opt = old_opts.s_mount_opt;
1077         sbi->s_resuid = old_opts.s_resuid;
1078         sbi->s_resgid = old_opts.s_resgid;
1079         sb->s_flags = old_sb_flags;
1080         return err;
1081 }
1082
1083 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1084 {
1085         struct super_block *sb = dentry->d_sb;
1086         struct ext2_sb_info *sbi = EXT2_SB(sb);
1087         unsigned long overhead;
1088         int i;
1089
1090         if (test_opt (sb, MINIX_DF))
1091                 overhead = 0;
1092         else {
1093                 /*
1094                  * Compute the overhead (FS structures)
1095                  */
1096
1097                 /*
1098                  * All of the blocks before first_data_block are
1099                  * overhead
1100                  */
1101                 overhead = le32_to_cpu(sbi->s_es->s_first_data_block);
1102
1103                 /*
1104                  * Add the overhead attributed to the superblock and
1105                  * block group descriptors.  If the sparse superblocks
1106                  * feature is turned on, then not all groups have this.
1107                  */
1108                 for (i = 0; i < sbi->s_groups_count; i++)
1109                         overhead += ext2_bg_has_super(sb, i) +
1110                                 ext2_bg_num_gdb(sb, i);
1111
1112                 /*
1113                  * Every block group has an inode bitmap, a block
1114                  * bitmap, and an inode table.
1115                  */
1116                 overhead += (sbi->s_groups_count *
1117                              (2 + sbi->s_itb_per_group));
1118         }
1119
1120         buf->f_type = EXT2_SUPER_MAGIC;
1121         buf->f_bsize = sb->s_blocksize;
1122         buf->f_blocks = le32_to_cpu(sbi->s_es->s_blocks_count) - overhead;
1123         buf->f_bfree = ext2_count_free_blocks(sb);
1124         buf->f_bavail = buf->f_bfree - le32_to_cpu(sbi->s_es->s_r_blocks_count);
1125         if (buf->f_bfree < le32_to_cpu(sbi->s_es->s_r_blocks_count))
1126                 buf->f_bavail = 0;
1127         buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);
1128         buf->f_ffree = ext2_count_free_inodes (sb);
1129         buf->f_namelen = EXT2_NAME_LEN;
1130         return 0;
1131 }
1132
1133 static int ext2_get_sb(struct file_system_type *fs_type,
1134         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1135 {
1136         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1137 }
1138
1139 #ifdef CONFIG_QUOTA
1140
1141 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1142  * acquiring the locks... As quota files are never truncated and quota code
1143  * itself serializes the operations (and noone else should touch the files)
1144  * we don't have to be afraid of races */
1145 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1146                                size_t len, loff_t off)
1147 {
1148         struct inode *inode = sb_dqopt(sb)->files[type];
1149         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1150         int err = 0;
1151         int offset = off & (sb->s_blocksize - 1);
1152         int tocopy;
1153         size_t toread;
1154         struct buffer_head tmp_bh;
1155         struct buffer_head *bh;
1156         loff_t i_size = i_size_read(inode);
1157
1158         if (off > i_size)
1159                 return 0;
1160         if (off+len > i_size)
1161                 len = i_size-off;
1162         toread = len;
1163         while (toread > 0) {
1164                 tocopy = sb->s_blocksize - offset < toread ?
1165                                 sb->s_blocksize - offset : toread;
1166
1167                 tmp_bh.b_state = 0;
1168                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1169                 if (err)
1170                         return err;
1171                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1172                         memset(data, 0, tocopy);
1173                 else {
1174                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1175                         if (!bh)
1176                                 return -EIO;
1177                         memcpy(data, bh->b_data+offset, tocopy);
1178                         brelse(bh);
1179                 }
1180                 offset = 0;
1181                 toread -= tocopy;
1182                 data += tocopy;
1183                 blk++;
1184         }
1185         return len;
1186 }
1187
1188 /* Write to quotafile */
1189 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1190                                 const char *data, size_t len, loff_t off)
1191 {
1192         struct inode *inode = sb_dqopt(sb)->files[type];
1193         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1194         int err = 0;
1195         int offset = off & (sb->s_blocksize - 1);
1196         int tocopy;
1197         size_t towrite = len;
1198         struct buffer_head tmp_bh;
1199         struct buffer_head *bh;
1200
1201         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1202         while (towrite > 0) {
1203                 tocopy = sb->s_blocksize - offset < towrite ?
1204                                 sb->s_blocksize - offset : towrite;
1205
1206                 tmp_bh.b_state = 0;
1207                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1208                 if (err)
1209                         goto out;
1210                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1211                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1212                 else
1213                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1214                 if (!bh) {
1215                         err = -EIO;
1216                         goto out;
1217                 }
1218                 lock_buffer(bh);
1219                 memcpy(bh->b_data+offset, data, tocopy);
1220                 flush_dcache_page(bh->b_page);
1221                 set_buffer_uptodate(bh);
1222                 mark_buffer_dirty(bh);
1223                 unlock_buffer(bh);
1224                 brelse(bh);
1225                 offset = 0;
1226                 towrite -= tocopy;
1227                 data += tocopy;
1228                 blk++;
1229         }
1230 out:
1231         if (len == towrite)
1232                 return err;
1233         if (inode->i_size < off+len-towrite)
1234                 i_size_write(inode, off+len-towrite);
1235         inode->i_version++;
1236         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1237         mark_inode_dirty(inode);
1238         mutex_unlock(&inode->i_mutex);
1239         return len - towrite;
1240 }
1241
1242 #endif
1243
1244 static struct file_system_type ext2_fs_type = {
1245         .owner          = THIS_MODULE,
1246         .name           = "ext2",
1247         .get_sb         = ext2_get_sb,
1248         .kill_sb        = kill_block_super,
1249         .fs_flags       = FS_REQUIRES_DEV,
1250 };
1251
1252 static int __init init_ext2_fs(void)
1253 {
1254         int err = init_ext2_xattr();
1255         if (err)
1256                 return err;
1257         err = init_inodecache();
1258         if (err)
1259                 goto out1;
1260         err = register_filesystem(&ext2_fs_type);
1261         if (err)
1262                 goto out;
1263         return 0;
1264 out:
1265         destroy_inodecache();
1266 out1:
1267         exit_ext2_xattr();
1268         return err;
1269 }
1270
1271 static void __exit exit_ext2_fs(void)
1272 {
1273         unregister_filesystem(&ext2_fs_type);
1274         destroy_inodecache();
1275         exit_ext2_xattr();
1276 }
1277
1278 module_init(init_ext2_fs)
1279 module_exit(exit_ext2_fs)