[PATCH] cpuset memory spread: slab cache filesystems
[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/config.h>
20 #include <linux/module.h>
21 #include <linux/string.h>
22 #include <linux/fs.h>
23 #include <linux/slab.h>
24 #include <linux/init.h>
25 #include <linux/blkdev.h>
26 #include <linux/parser.h>
27 #include <linux/random.h>
28 #include <linux/buffer_head.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 <asm/uaccess.h>
34 #include "ext2.h"
35 #include "xattr.h"
36 #include "acl.h"
37 #include "xip.h"
38
39 static void ext2_sync_super(struct super_block *sb,
40                             struct ext2_super_block *es);
41 static int ext2_remount (struct super_block * sb, int * flags, char * data);
42 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf);
43
44 void ext2_error (struct super_block * sb, const char * function,
45                  const char * fmt, ...)
46 {
47         va_list args;
48         struct ext2_sb_info *sbi = EXT2_SB(sb);
49         struct ext2_super_block *es = sbi->s_es;
50
51         if (!(sb->s_flags & MS_RDONLY)) {
52                 sbi->s_mount_state |= EXT2_ERROR_FS;
53                 es->s_state =
54                         cpu_to_le16(le16_to_cpu(es->s_state) | EXT2_ERROR_FS);
55                 ext2_sync_super(sb, es);
56         }
57
58         va_start(args, fmt);
59         printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
60         vprintk(fmt, args);
61         printk("\n");
62         va_end(args);
63
64         if (test_opt(sb, ERRORS_PANIC))
65                 panic("EXT2-fs panic from previous error\n");
66         if (test_opt(sb, ERRORS_RO)) {
67                 printk("Remounting filesystem read-only\n");
68                 sb->s_flags |= MS_RDONLY;
69         }
70 }
71
72 void ext2_warning (struct super_block * sb, const char * function,
73                    const char * fmt, ...)
74 {
75         va_list args;
76
77         va_start(args, fmt);
78         printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
79                sb->s_id, function);
80         vprintk(fmt, args);
81         printk("\n");
82         va_end(args);
83 }
84
85 void ext2_update_dynamic_rev(struct super_block *sb)
86 {
87         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
88
89         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
90                 return;
91
92         ext2_warning(sb, __FUNCTION__,
93                      "updating to rev %d because of new feature flag, "
94                      "running e2fsck is recommended",
95                      EXT2_DYNAMIC_REV);
96
97         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
98         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
99         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
100         /* leave es->s_feature_*compat flags alone */
101         /* es->s_uuid will be set by e2fsck if empty */
102
103         /*
104          * The rest of the superblock fields should be zero, and if not it
105          * means they are likely already in use, so leave them alone.  We
106          * can leave it up to e2fsck to clean up any inconsistencies there.
107          */
108 }
109
110 static void ext2_put_super (struct super_block * sb)
111 {
112         int db_count;
113         int i;
114         struct ext2_sb_info *sbi = EXT2_SB(sb);
115
116         ext2_xattr_put_super(sb);
117         if (!(sb->s_flags & MS_RDONLY)) {
118                 struct ext2_super_block *es = sbi->s_es;
119
120                 es->s_state = cpu_to_le16(sbi->s_mount_state);
121                 ext2_sync_super(sb, es);
122         }
123         db_count = sbi->s_gdb_count;
124         for (i = 0; i < db_count; i++)
125                 if (sbi->s_group_desc[i])
126                         brelse (sbi->s_group_desc[i]);
127         kfree(sbi->s_group_desc);
128         kfree(sbi->s_debts);
129         percpu_counter_destroy(&sbi->s_freeblocks_counter);
130         percpu_counter_destroy(&sbi->s_freeinodes_counter);
131         percpu_counter_destroy(&sbi->s_dirs_counter);
132         brelse (sbi->s_sbh);
133         sb->s_fs_info = NULL;
134         kfree(sbi);
135
136         return;
137 }
138
139 static kmem_cache_t * ext2_inode_cachep;
140
141 static struct inode *ext2_alloc_inode(struct super_block *sb)
142 {
143         struct ext2_inode_info *ei;
144         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, SLAB_KERNEL);
145         if (!ei)
146                 return NULL;
147 #ifdef CONFIG_EXT2_FS_POSIX_ACL
148         ei->i_acl = EXT2_ACL_NOT_CACHED;
149         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
150 #endif
151         ei->vfs_inode.i_version = 1;
152         return &ei->vfs_inode;
153 }
154
155 static void ext2_destroy_inode(struct inode *inode)
156 {
157         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
158 }
159
160 static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
161 {
162         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
163
164         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
165             SLAB_CTOR_CONSTRUCTOR) {
166                 rwlock_init(&ei->i_meta_lock);
167 #ifdef CONFIG_EXT2_FS_XATTR
168                 init_rwsem(&ei->xattr_sem);
169 #endif
170                 inode_init_once(&ei->vfs_inode);
171         }
172 }
173  
174 static int init_inodecache(void)
175 {
176         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
177                                              sizeof(struct ext2_inode_info),
178                                              0, SLAB_RECLAIM_ACCOUNT|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         if (kmem_cache_destroy(ext2_inode_cachep))
188                 printk(KERN_INFO "ext2_inode_cache: not all structures were freed\n");
189 }
190
191 static void ext2_clear_inode(struct inode *inode)
192 {
193 #ifdef CONFIG_EXT2_FS_POSIX_ACL
194         struct ext2_inode_info *ei = EXT2_I(inode);
195
196         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
197                 posix_acl_release(ei->i_acl);
198                 ei->i_acl = EXT2_ACL_NOT_CACHED;
199         }
200         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
201                 posix_acl_release(ei->i_default_acl);
202                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
203         }
204 #endif
205 }
206
207 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
208 {
209         struct ext2_sb_info *sbi = EXT2_SB(vfs->mnt_sb);
210
211         if (sbi->s_mount_opt & EXT2_MOUNT_GRPID)
212                 seq_puts(seq, ",grpid");
213         else
214                 seq_puts(seq, ",nogrpid");
215
216 #if defined(CONFIG_QUOTA)
217         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
218                 seq_puts(seq, ",usrquota");
219
220         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
221                 seq_puts(seq, ",grpquota");
222 #endif
223
224 #if defined(CONFIG_EXT2_FS_XIP)
225         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
226                 seq_puts(seq, ",xip");
227 #endif
228
229         return 0;
230 }
231
232 #ifdef CONFIG_QUOTA
233 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
234 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
235 #endif
236
237 static struct super_operations ext2_sops = {
238         .alloc_inode    = ext2_alloc_inode,
239         .destroy_inode  = ext2_destroy_inode,
240         .read_inode     = ext2_read_inode,
241         .write_inode    = ext2_write_inode,
242         .put_inode      = ext2_put_inode,
243         .delete_inode   = ext2_delete_inode,
244         .put_super      = ext2_put_super,
245         .write_super    = ext2_write_super,
246         .statfs         = ext2_statfs,
247         .remount_fs     = ext2_remount,
248         .clear_inode    = ext2_clear_inode,
249         .show_options   = ext2_show_options,
250 #ifdef CONFIG_QUOTA
251         .quota_read     = ext2_quota_read,
252         .quota_write    = ext2_quota_write,
253 #endif
254 };
255
256 /* Yes, most of these are left as NULL!!
257  * A NULL value implies the default, which works with ext2-like file
258  * systems, but can be improved upon.
259  * Currently only get_parent is required.
260  */
261 static struct export_operations ext2_export_ops = {
262         .get_parent = ext2_get_parent,
263 };
264
265 static unsigned long get_sb_block(void **data)
266 {
267         unsigned long   sb_block;
268         char            *options = (char *) *data;
269
270         if (!options || strncmp(options, "sb=", 3) != 0)
271                 return 1;       /* Default location */
272         options += 3;
273         sb_block = simple_strtoul(options, &options, 0);
274         if (*options && *options != ',') {
275                 printk("EXT2-fs: Invalid sb specification: %s\n",
276                        (char *) *data);
277                 return 1;
278         }
279         if (*options == ',')
280                 options++;
281         *data = (void *) options;
282         return sb_block;
283 }
284
285 enum {
286         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
287         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
288         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
289         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
290         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
291         Opt_usrquota, Opt_grpquota
292 };
293
294 static match_table_t tokens = {
295         {Opt_bsd_df, "bsddf"},
296         {Opt_minix_df, "minixdf"},
297         {Opt_grpid, "grpid"},
298         {Opt_grpid, "bsdgroups"},
299         {Opt_nogrpid, "nogrpid"},
300         {Opt_nogrpid, "sysvgroups"},
301         {Opt_resgid, "resgid=%u"},
302         {Opt_resuid, "resuid=%u"},
303         {Opt_sb, "sb=%u"},
304         {Opt_err_cont, "errors=continue"},
305         {Opt_err_panic, "errors=panic"},
306         {Opt_err_ro, "errors=remount-ro"},
307         {Opt_nouid32, "nouid32"},
308         {Opt_nocheck, "check=none"},
309         {Opt_nocheck, "nocheck"},
310         {Opt_debug, "debug"},
311         {Opt_oldalloc, "oldalloc"},
312         {Opt_orlov, "orlov"},
313         {Opt_nobh, "nobh"},
314         {Opt_user_xattr, "user_xattr"},
315         {Opt_nouser_xattr, "nouser_xattr"},
316         {Opt_acl, "acl"},
317         {Opt_noacl, "noacl"},
318         {Opt_xip, "xip"},
319         {Opt_grpquota, "grpquota"},
320         {Opt_ignore, "noquota"},
321         {Opt_quota, "quota"},
322         {Opt_usrquota, "usrquota"},
323         {Opt_err, NULL}
324 };
325
326 static int parse_options (char * options,
327                           struct ext2_sb_info *sbi)
328 {
329         char * p;
330         substring_t args[MAX_OPT_ARGS];
331         unsigned long kind = EXT2_MOUNT_ERRORS_CONT;
332         int option;
333
334         if (!options)
335                 return 1;
336
337         while ((p = strsep (&options, ",")) != NULL) {
338                 int token;
339                 if (!*p)
340                         continue;
341
342                 token = match_token(p, tokens, args);
343                 switch (token) {
344                 case Opt_bsd_df:
345                         clear_opt (sbi->s_mount_opt, MINIX_DF);
346                         break;
347                 case Opt_minix_df:
348                         set_opt (sbi->s_mount_opt, MINIX_DF);
349                         break;
350                 case Opt_grpid:
351                         set_opt (sbi->s_mount_opt, GRPID);
352                         break;
353                 case Opt_nogrpid:
354                         clear_opt (sbi->s_mount_opt, GRPID);
355                         break;
356                 case Opt_resuid:
357                         if (match_int(&args[0], &option))
358                                 return 0;
359                         sbi->s_resuid = option;
360                         break;
361                 case Opt_resgid:
362                         if (match_int(&args[0], &option))
363                                 return 0;
364                         sbi->s_resgid = option;
365                         break;
366                 case Opt_sb:
367                         /* handled by get_sb_block() instead of here */
368                         /* *sb_block = match_int(&args[0]); */
369                         break;
370                 case Opt_err_panic:
371                         kind = EXT2_MOUNT_ERRORS_PANIC;
372                         break;
373                 case Opt_err_ro:
374                         kind = EXT2_MOUNT_ERRORS_RO;
375                         break;
376                 case Opt_err_cont:
377                         kind = EXT2_MOUNT_ERRORS_CONT;
378                         break;
379                 case Opt_nouid32:
380                         set_opt (sbi->s_mount_opt, NO_UID32);
381                         break;
382                 case Opt_nocheck:
383                         clear_opt (sbi->s_mount_opt, CHECK);
384                         break;
385                 case Opt_debug:
386                         set_opt (sbi->s_mount_opt, DEBUG);
387                         break;
388                 case Opt_oldalloc:
389                         set_opt (sbi->s_mount_opt, OLDALLOC);
390                         break;
391                 case Opt_orlov:
392                         clear_opt (sbi->s_mount_opt, OLDALLOC);
393                         break;
394                 case Opt_nobh:
395                         set_opt (sbi->s_mount_opt, NOBH);
396                         break;
397 #ifdef CONFIG_EXT2_FS_XATTR
398                 case Opt_user_xattr:
399                         set_opt (sbi->s_mount_opt, XATTR_USER);
400                         break;
401                 case Opt_nouser_xattr:
402                         clear_opt (sbi->s_mount_opt, XATTR_USER);
403                         break;
404 #else
405                 case Opt_user_xattr:
406                 case Opt_nouser_xattr:
407                         printk("EXT2 (no)user_xattr options not supported\n");
408                         break;
409 #endif
410 #ifdef CONFIG_EXT2_FS_POSIX_ACL
411                 case Opt_acl:
412                         set_opt(sbi->s_mount_opt, POSIX_ACL);
413                         break;
414                 case Opt_noacl:
415                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
416                         break;
417 #else
418                 case Opt_acl:
419                 case Opt_noacl:
420                         printk("EXT2 (no)acl options not supported\n");
421                         break;
422 #endif
423                 case Opt_xip:
424 #ifdef CONFIG_EXT2_FS_XIP
425                         set_opt (sbi->s_mount_opt, XIP);
426 #else
427                         printk("EXT2 xip option not supported\n");
428 #endif
429                         break;
430
431 #if defined(CONFIG_QUOTA)
432                 case Opt_quota:
433                 case Opt_usrquota:
434                         set_opt(sbi->s_mount_opt, USRQUOTA);
435                         break;
436
437                 case Opt_grpquota:
438                         set_opt(sbi->s_mount_opt, GRPQUOTA);
439                         break;
440 #else
441                 case Opt_quota:
442                 case Opt_usrquota:
443                 case Opt_grpquota:
444                         printk(KERN_ERR
445                                 "EXT2-fs: quota operations not supported.\n");
446
447                         break;
448 #endif
449
450                 case Opt_ignore:
451                         break;
452                 default:
453                         return 0;
454                 }
455         }
456         sbi->s_mount_opt |= kind;
457         return 1;
458 }
459
460 static int ext2_setup_super (struct super_block * sb,
461                               struct ext2_super_block * es,
462                               int read_only)
463 {
464         int res = 0;
465         struct ext2_sb_info *sbi = EXT2_SB(sb);
466
467         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
468                 printk ("EXT2-fs warning: revision level too high, "
469                         "forcing read-only mode\n");
470                 res = MS_RDONLY;
471         }
472         if (read_only)
473                 return res;
474         if (!(sbi->s_mount_state & EXT2_VALID_FS))
475                 printk ("EXT2-fs warning: mounting unchecked fs, "
476                         "running e2fsck is recommended\n");
477         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
478                 printk ("EXT2-fs warning: mounting fs with errors, "
479                         "running e2fsck is recommended\n");
480         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
481                  le16_to_cpu(es->s_mnt_count) >=
482                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
483                 printk ("EXT2-fs warning: maximal mount count reached, "
484                         "running e2fsck is recommended\n");
485         else if (le32_to_cpu(es->s_checkinterval) &&
486                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
487                 printk ("EXT2-fs warning: checktime reached, "
488                         "running e2fsck is recommended\n");
489         if (!le16_to_cpu(es->s_max_mnt_count))
490                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
491         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
492         ext2_write_super(sb);
493         if (test_opt (sb, DEBUG))
494                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
495                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
496                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
497                         sbi->s_frag_size,
498                         sbi->s_groups_count,
499                         EXT2_BLOCKS_PER_GROUP(sb),
500                         EXT2_INODES_PER_GROUP(sb),
501                         sbi->s_mount_opt);
502         return res;
503 }
504
505 static int ext2_check_descriptors (struct super_block * sb)
506 {
507         int i;
508         int desc_block = 0;
509         struct ext2_sb_info *sbi = EXT2_SB(sb);
510         unsigned long block = le32_to_cpu(sbi->s_es->s_first_data_block);
511         struct ext2_group_desc * gdp = NULL;
512
513         ext2_debug ("Checking group descriptors");
514
515         for (i = 0; i < sbi->s_groups_count; i++)
516         {
517                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
518                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
519                 if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
520                     le32_to_cpu(gdp->bg_block_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
521                 {
522                         ext2_error (sb, "ext2_check_descriptors",
523                                     "Block bitmap for group %d"
524                                     " not in group (block %lu)!",
525                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
526                         return 0;
527                 }
528                 if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
529                     le32_to_cpu(gdp->bg_inode_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
530                 {
531                         ext2_error (sb, "ext2_check_descriptors",
532                                     "Inode bitmap for group %d"
533                                     " not in group (block %lu)!",
534                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
535                         return 0;
536                 }
537                 if (le32_to_cpu(gdp->bg_inode_table) < block ||
538                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
539                     block + EXT2_BLOCKS_PER_GROUP(sb))
540                 {
541                         ext2_error (sb, "ext2_check_descriptors",
542                                     "Inode table for group %d"
543                                     " not in group (block %lu)!",
544                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
545                         return 0;
546                 }
547                 block += EXT2_BLOCKS_PER_GROUP(sb);
548                 gdp++;
549         }
550         return 1;
551 }
552
553 #define log2(n) ffz(~(n))
554  
555 /*
556  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
557  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
558  * We need to be 1 filesystem block less than the 2^32 sector limit.
559  */
560 static loff_t ext2_max_size(int bits)
561 {
562         loff_t res = EXT2_NDIR_BLOCKS;
563         /* This constant is calculated to be the largest file size for a
564          * dense, 4k-blocksize file such that the total number of
565          * sectors in the file, including data and all indirect blocks,
566          * does not exceed 2^32. */
567         const loff_t upper_limit = 0x1ff7fffd000LL;
568
569         res += 1LL << (bits-2);
570         res += 1LL << (2*(bits-2));
571         res += 1LL << (3*(bits-2));
572         res <<= bits;
573         if (res > upper_limit)
574                 res = upper_limit;
575         return res;
576 }
577
578 static unsigned long descriptor_loc(struct super_block *sb,
579                                     unsigned long logic_sb_block,
580                                     int nr)
581 {
582         struct ext2_sb_info *sbi = EXT2_SB(sb);
583         unsigned long bg, first_data_block, first_meta_bg;
584         int has_super = 0;
585         
586         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
587         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
588
589         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
590             nr < first_meta_bg)
591                 return (logic_sb_block + nr + 1);
592         bg = sbi->s_desc_per_block * nr;
593         if (ext2_bg_has_super(sb, bg))
594                 has_super = 1;
595         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
596 }
597
598 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
599 {
600         struct buffer_head * bh;
601         struct ext2_sb_info * sbi;
602         struct ext2_super_block * es;
603         struct inode *root;
604         unsigned long block;
605         unsigned long sb_block = get_sb_block(&data);
606         unsigned long logic_sb_block;
607         unsigned long offset = 0;
608         unsigned long def_mount_opts;
609         int blocksize = BLOCK_SIZE;
610         int db_count;
611         int i, j;
612         __le32 features;
613
614         sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
615         if (!sbi)
616                 return -ENOMEM;
617         sb->s_fs_info = sbi;
618         memset(sbi, 0, sizeof(*sbi));
619
620         /*
621          * See what the current blocksize for the device is, and
622          * use that as the blocksize.  Otherwise (or if the blocksize
623          * is smaller than the default) use the default.
624          * This is important for devices that have a hardware
625          * sectorsize that is larger than the default.
626          */
627         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
628         if (!blocksize) {
629                 printk ("EXT2-fs: unable to set blocksize\n");
630                 goto failed_sbi;
631         }
632
633         /*
634          * If the superblock doesn't start on a hardware sector boundary,
635          * calculate the offset.  
636          */
637         if (blocksize != BLOCK_SIZE) {
638                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
639                 offset = (sb_block*BLOCK_SIZE) % blocksize;
640         } else {
641                 logic_sb_block = sb_block;
642         }
643
644         if (!(bh = sb_bread(sb, logic_sb_block))) {
645                 printk ("EXT2-fs: unable to read superblock\n");
646                 goto failed_sbi;
647         }
648         /*
649          * Note: s_es must be initialized as soon as possible because
650          *       some ext2 macro-instructions depend on its value
651          */
652         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
653         sbi->s_es = es;
654         sb->s_magic = le16_to_cpu(es->s_magic);
655
656         if (sb->s_magic != EXT2_SUPER_MAGIC)
657                 goto cantfind_ext2;
658
659         /* Set defaults before we parse the mount options */
660         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
661         if (def_mount_opts & EXT2_DEFM_DEBUG)
662                 set_opt(sbi->s_mount_opt, DEBUG);
663         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
664                 set_opt(sbi->s_mount_opt, GRPID);
665         if (def_mount_opts & EXT2_DEFM_UID16)
666                 set_opt(sbi->s_mount_opt, NO_UID32);
667         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
668                 set_opt(sbi->s_mount_opt, XATTR_USER);
669         if (def_mount_opts & EXT2_DEFM_ACL)
670                 set_opt(sbi->s_mount_opt, POSIX_ACL);
671         
672         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
673                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
674         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
675                 set_opt(sbi->s_mount_opt, ERRORS_RO);
676
677         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
678         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
679         
680         if (!parse_options ((char *) data, sbi))
681                 goto failed_mount;
682
683         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
684                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
685                  MS_POSIXACL : 0);
686
687         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
688                                     EXT2_MOUNT_XIP if not */
689
690         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
691             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
692              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
693              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
694                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
695                        "running e2fsck is recommended\n");
696         /*
697          * Check feature flags regardless of the revision level, since we
698          * previously didn't change the revision level when setting the flags,
699          * so there is a chance incompat flags are set on a rev 0 filesystem.
700          */
701         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
702         if (features) {
703                 printk("EXT2-fs: %s: couldn't mount because of "
704                        "unsupported optional features (%x).\n",
705                        sb->s_id, le32_to_cpu(features));
706                 goto failed_mount;
707         }
708         if (!(sb->s_flags & MS_RDONLY) &&
709             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
710                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
711                        "unsupported optional features (%x).\n",
712                        sb->s_id, le32_to_cpu(features));
713                 goto failed_mount;
714         }
715
716         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
717
718         if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
719                                   (sb->s_blocksize != blocksize))) {
720                 if (!silent)
721                         printk("XIP: Unsupported blocksize\n");
722                 goto failed_mount;
723         }
724
725         /* If the blocksize doesn't match, re-read the thing.. */
726         if (sb->s_blocksize != blocksize) {
727                 brelse(bh);
728
729                 if (!sb_set_blocksize(sb, blocksize)) {
730                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
731                         goto failed_sbi;
732                 }
733
734                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
735                 offset = (sb_block*BLOCK_SIZE) % blocksize;
736                 bh = sb_bread(sb, logic_sb_block);
737                 if(!bh) {
738                         printk("EXT2-fs: Couldn't read superblock on "
739                                "2nd try.\n");
740                         goto failed_sbi;
741                 }
742                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
743                 sbi->s_es = es;
744                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
745                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
746                         goto failed_mount;
747                 }
748         }
749
750         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
751
752         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
753                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
754                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
755         } else {
756                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
757                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
758                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
759                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
760                     (sbi->s_inode_size > blocksize)) {
761                         printk ("EXT2-fs: unsupported inode size: %d\n",
762                                 sbi->s_inode_size);
763                         goto failed_mount;
764                 }
765         }
766
767         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
768                                    le32_to_cpu(es->s_log_frag_size);
769         if (sbi->s_frag_size == 0)
770                 goto cantfind_ext2;
771         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
772
773         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
774         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
775         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
776
777         if (EXT2_INODE_SIZE(sb) == 0)
778                 goto cantfind_ext2;
779         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
780         if (sbi->s_inodes_per_block == 0)
781                 goto cantfind_ext2;
782         sbi->s_itb_per_group = sbi->s_inodes_per_group /
783                                         sbi->s_inodes_per_block;
784         sbi->s_desc_per_block = sb->s_blocksize /
785                                         sizeof (struct ext2_group_desc);
786         sbi->s_sbh = bh;
787         sbi->s_mount_state = le16_to_cpu(es->s_state);
788         sbi->s_addr_per_block_bits =
789                 log2 (EXT2_ADDR_PER_BLOCK(sb));
790         sbi->s_desc_per_block_bits =
791                 log2 (EXT2_DESC_PER_BLOCK(sb));
792
793         if (sb->s_magic != EXT2_SUPER_MAGIC)
794                 goto cantfind_ext2;
795
796         if (sb->s_blocksize != bh->b_size) {
797                 if (!silent)
798                         printk ("VFS: Unsupported blocksize on dev "
799                                 "%s.\n", sb->s_id);
800                 goto failed_mount;
801         }
802
803         if (sb->s_blocksize != sbi->s_frag_size) {
804                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
805                         sbi->s_frag_size, sb->s_blocksize);
806                 goto failed_mount;
807         }
808
809         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
810                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
811                         sbi->s_blocks_per_group);
812                 goto failed_mount;
813         }
814         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
815                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
816                         sbi->s_frags_per_group);
817                 goto failed_mount;
818         }
819         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
820                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
821                         sbi->s_inodes_per_group);
822                 goto failed_mount;
823         }
824
825         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
826                 goto cantfind_ext2;
827         sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
828                                         le32_to_cpu(es->s_first_data_block) +
829                                        EXT2_BLOCKS_PER_GROUP(sb) - 1) /
830                                        EXT2_BLOCKS_PER_GROUP(sb);
831         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
832                    EXT2_DESC_PER_BLOCK(sb);
833         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
834         if (sbi->s_group_desc == NULL) {
835                 printk ("EXT2-fs: not enough memory\n");
836                 goto failed_mount;
837         }
838         percpu_counter_init(&sbi->s_freeblocks_counter);
839         percpu_counter_init(&sbi->s_freeinodes_counter);
840         percpu_counter_init(&sbi->s_dirs_counter);
841         bgl_lock_init(&sbi->s_blockgroup_lock);
842         sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
843                                GFP_KERNEL);
844         if (!sbi->s_debts) {
845                 printk ("EXT2-fs: not enough memory\n");
846                 goto failed_mount_group_desc;
847         }
848         memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
849         for (i = 0; i < db_count; i++) {
850                 block = descriptor_loc(sb, logic_sb_block, i);
851                 sbi->s_group_desc[i] = sb_bread(sb, block);
852                 if (!sbi->s_group_desc[i]) {
853                         for (j = 0; j < i; j++)
854                                 brelse (sbi->s_group_desc[j]);
855                         printk ("EXT2-fs: unable to read group descriptors\n");
856                         goto failed_mount_group_desc;
857                 }
858         }
859         if (!ext2_check_descriptors (sb)) {
860                 printk ("EXT2-fs: group descriptors corrupted!\n");
861                 db_count = i;
862                 goto failed_mount2;
863         }
864         sbi->s_gdb_count = db_count;
865         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
866         spin_lock_init(&sbi->s_next_gen_lock);
867         /*
868          * set up enough so that it can read an inode
869          */
870         sb->s_op = &ext2_sops;
871         sb->s_export_op = &ext2_export_ops;
872         sb->s_xattr = ext2_xattr_handlers;
873         root = iget(sb, EXT2_ROOT_INO);
874         sb->s_root = d_alloc_root(root);
875         if (!sb->s_root) {
876                 iput(root);
877                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
878                 goto failed_mount2;
879         }
880         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
881                 dput(sb->s_root);
882                 sb->s_root = NULL;
883                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
884                 goto failed_mount2;
885         }
886         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
887                 ext2_warning(sb, __FUNCTION__,
888                         "mounting ext3 filesystem as ext2");
889         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
890         percpu_counter_mod(&sbi->s_freeblocks_counter,
891                                 ext2_count_free_blocks(sb));
892         percpu_counter_mod(&sbi->s_freeinodes_counter,
893                                 ext2_count_free_inodes(sb));
894         percpu_counter_mod(&sbi->s_dirs_counter,
895                                 ext2_count_dirs(sb));
896         return 0;
897
898 cantfind_ext2:
899         if (!silent)
900                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
901                        sb->s_id);
902         goto failed_mount;
903
904 failed_mount2:
905         for (i = 0; i < db_count; i++)
906                 brelse(sbi->s_group_desc[i]);
907 failed_mount_group_desc:
908         kfree(sbi->s_group_desc);
909         kfree(sbi->s_debts);
910 failed_mount:
911         brelse(bh);
912 failed_sbi:
913         sb->s_fs_info = NULL;
914         kfree(sbi);
915         return -EINVAL;
916 }
917
918 static void ext2_commit_super (struct super_block * sb,
919                                struct ext2_super_block * es)
920 {
921         es->s_wtime = cpu_to_le32(get_seconds());
922         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
923         sb->s_dirt = 0;
924 }
925
926 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
927 {
928         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
929         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
930         es->s_wtime = cpu_to_le32(get_seconds());
931         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
932         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
933         sb->s_dirt = 0;
934 }
935
936 /*
937  * In the second extended file system, it is not necessary to
938  * write the super block since we use a mapping of the
939  * disk super block in a buffer.
940  *
941  * However, this function is still used to set the fs valid
942  * flags to 0.  We need to set this flag to 0 since the fs
943  * may have been checked while mounted and e2fsck may have
944  * set s_state to EXT2_VALID_FS after some corrections.
945  */
946
947 void ext2_write_super (struct super_block * sb)
948 {
949         struct ext2_super_block * es;
950         lock_kernel();
951         if (!(sb->s_flags & MS_RDONLY)) {
952                 es = EXT2_SB(sb)->s_es;
953
954                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
955                         ext2_debug ("setting valid to 0\n");
956                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
957                                                   ~EXT2_VALID_FS);
958                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
959                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
960                         es->s_mtime = cpu_to_le32(get_seconds());
961                         ext2_sync_super(sb, es);
962                 } else
963                         ext2_commit_super (sb, es);
964         }
965         sb->s_dirt = 0;
966         unlock_kernel();
967 }
968
969 static int ext2_remount (struct super_block * sb, int * flags, char * data)
970 {
971         struct ext2_sb_info * sbi = EXT2_SB(sb);
972         struct ext2_super_block * es;
973         unsigned long old_mount_opt = sbi->s_mount_opt;
974         struct ext2_mount_options old_opts;
975         unsigned long old_sb_flags;
976         int err;
977
978         /* Store the old options */
979         old_sb_flags = sb->s_flags;
980         old_opts.s_mount_opt = sbi->s_mount_opt;
981         old_opts.s_resuid = sbi->s_resuid;
982         old_opts.s_resgid = sbi->s_resgid;
983
984         /*
985          * Allow the "check" option to be passed as a remount option.
986          */
987         if (!parse_options (data, sbi)) {
988                 err = -EINVAL;
989                 goto restore_opts;
990         }
991
992         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
993                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
994
995         es = sbi->s_es;
996         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
997             (old_mount_opt & EXT2_MOUNT_XIP)) &&
998             invalidate_inodes(sb))
999                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1000                              "xip remain in cache (no functional problem)");
1001         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1002                 return 0;
1003         if (*flags & MS_RDONLY) {
1004                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1005                     !(sbi->s_mount_state & EXT2_VALID_FS))
1006                         return 0;
1007                 /*
1008                  * OK, we are remounting a valid rw partition rdonly, so set
1009                  * the rdonly flag and then mark the partition as valid again.
1010                  */
1011                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1012                 es->s_mtime = cpu_to_le32(get_seconds());
1013         } else {
1014                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1015                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1016                 if (ret) {
1017                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1018                                "unsupported optional features (%x).\n",
1019                                sb->s_id, le32_to_cpu(ret));
1020                         err = -EROFS;
1021                         goto restore_opts;
1022                 }
1023                 /*
1024                  * Mounting a RDONLY partition read-write, so reread and
1025                  * store the current valid flag.  (It may have been changed
1026                  * by e2fsck since we originally mounted the partition.)
1027                  */
1028                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1029                 if (!ext2_setup_super (sb, es, 0))
1030                         sb->s_flags &= ~MS_RDONLY;
1031         }
1032         ext2_sync_super(sb, es);
1033         return 0;
1034 restore_opts:
1035         sbi->s_mount_opt = old_opts.s_mount_opt;
1036         sbi->s_resuid = old_opts.s_resuid;
1037         sbi->s_resgid = old_opts.s_resgid;
1038         sb->s_flags = old_sb_flags;
1039         return err;
1040 }
1041
1042 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf)
1043 {
1044         struct ext2_sb_info *sbi = EXT2_SB(sb);
1045         unsigned long overhead;
1046         int i;
1047
1048         if (test_opt (sb, MINIX_DF))
1049                 overhead = 0;
1050         else {
1051                 /*
1052                  * Compute the overhead (FS structures)
1053                  */
1054
1055                 /*
1056                  * All of the blocks before first_data_block are
1057                  * overhead
1058                  */
1059                 overhead = le32_to_cpu(sbi->s_es->s_first_data_block);
1060
1061                 /*
1062                  * Add the overhead attributed to the superblock and
1063                  * block group descriptors.  If the sparse superblocks
1064                  * feature is turned on, then not all groups have this.
1065                  */
1066                 for (i = 0; i < sbi->s_groups_count; i++)
1067                         overhead += ext2_bg_has_super(sb, i) +
1068                                 ext2_bg_num_gdb(sb, i);
1069
1070                 /*
1071                  * Every block group has an inode bitmap, a block
1072                  * bitmap, and an inode table.
1073                  */
1074                 overhead += (sbi->s_groups_count *
1075                              (2 + sbi->s_itb_per_group));
1076         }
1077
1078         buf->f_type = EXT2_SUPER_MAGIC;
1079         buf->f_bsize = sb->s_blocksize;
1080         buf->f_blocks = le32_to_cpu(sbi->s_es->s_blocks_count) - overhead;
1081         buf->f_bfree = ext2_count_free_blocks(sb);
1082         buf->f_bavail = buf->f_bfree - le32_to_cpu(sbi->s_es->s_r_blocks_count);
1083         if (buf->f_bfree < le32_to_cpu(sbi->s_es->s_r_blocks_count))
1084                 buf->f_bavail = 0;
1085         buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);
1086         buf->f_ffree = ext2_count_free_inodes (sb);
1087         buf->f_namelen = EXT2_NAME_LEN;
1088         return 0;
1089 }
1090
1091 static struct super_block *ext2_get_sb(struct file_system_type *fs_type,
1092         int flags, const char *dev_name, void *data)
1093 {
1094         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1095 }
1096
1097 #ifdef CONFIG_QUOTA
1098
1099 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1100  * acquiring the locks... As quota files are never truncated and quota code
1101  * itself serializes the operations (and noone else should touch the files)
1102  * we don't have to be afraid of races */
1103 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1104                                size_t len, loff_t off)
1105 {
1106         struct inode *inode = sb_dqopt(sb)->files[type];
1107         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1108         int err = 0;
1109         int offset = off & (sb->s_blocksize - 1);
1110         int tocopy;
1111         size_t toread;
1112         struct buffer_head tmp_bh;
1113         struct buffer_head *bh;
1114         loff_t i_size = i_size_read(inode);
1115
1116         if (off > i_size)
1117                 return 0;
1118         if (off+len > i_size)
1119                 len = i_size-off;
1120         toread = len;
1121         while (toread > 0) {
1122                 tocopy = sb->s_blocksize - offset < toread ?
1123                                 sb->s_blocksize - offset : toread;
1124
1125                 tmp_bh.b_state = 0;
1126                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1127                 if (err)
1128                         return err;
1129                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1130                         memset(data, 0, tocopy);
1131                 else {
1132                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1133                         if (!bh)
1134                                 return -EIO;
1135                         memcpy(data, bh->b_data+offset, tocopy);
1136                         brelse(bh);
1137                 }
1138                 offset = 0;
1139                 toread -= tocopy;
1140                 data += tocopy;
1141                 blk++;
1142         }
1143         return len;
1144 }
1145
1146 /* Write to quotafile */
1147 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1148                                 const char *data, size_t len, loff_t off)
1149 {
1150         struct inode *inode = sb_dqopt(sb)->files[type];
1151         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1152         int err = 0;
1153         int offset = off & (sb->s_blocksize - 1);
1154         int tocopy;
1155         size_t towrite = len;
1156         struct buffer_head tmp_bh;
1157         struct buffer_head *bh;
1158
1159         mutex_lock(&inode->i_mutex);
1160         while (towrite > 0) {
1161                 tocopy = sb->s_blocksize - offset < towrite ?
1162                                 sb->s_blocksize - offset : towrite;
1163
1164                 tmp_bh.b_state = 0;
1165                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1166                 if (err)
1167                         goto out;
1168                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1169                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1170                 else
1171                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1172                 if (!bh) {
1173                         err = -EIO;
1174                         goto out;
1175                 }
1176                 lock_buffer(bh);
1177                 memcpy(bh->b_data+offset, data, tocopy);
1178                 flush_dcache_page(bh->b_page);
1179                 set_buffer_uptodate(bh);
1180                 mark_buffer_dirty(bh);
1181                 unlock_buffer(bh);
1182                 brelse(bh);
1183                 offset = 0;
1184                 towrite -= tocopy;
1185                 data += tocopy;
1186                 blk++;
1187         }
1188 out:
1189         if (len == towrite)
1190                 return err;
1191         if (inode->i_size < off+len-towrite)
1192                 i_size_write(inode, off+len-towrite);
1193         inode->i_version++;
1194         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1195         mark_inode_dirty(inode);
1196         mutex_unlock(&inode->i_mutex);
1197         return len - towrite;
1198 }
1199
1200 #endif
1201
1202 static struct file_system_type ext2_fs_type = {
1203         .owner          = THIS_MODULE,
1204         .name           = "ext2",
1205         .get_sb         = ext2_get_sb,
1206         .kill_sb        = kill_block_super,
1207         .fs_flags       = FS_REQUIRES_DEV,
1208 };
1209
1210 static int __init init_ext2_fs(void)
1211 {
1212         int err = init_ext2_xattr();
1213         if (err)
1214                 return err;
1215         err = init_inodecache();
1216         if (err)
1217                 goto out1;
1218         err = register_filesystem(&ext2_fs_type);
1219         if (err)
1220                 goto out;
1221         return 0;
1222 out:
1223         destroy_inodecache();
1224 out1:
1225         exit_ext2_xattr();
1226         return err;
1227 }
1228
1229 static void __exit exit_ext2_fs(void)
1230 {
1231         unregister_filesystem(&ext2_fs_type);
1232         destroy_inodecache();
1233         exit_ext2_xattr();
1234 }
1235
1236 module_init(init_ext2_fs)
1237 module_exit(exit_ext2_fs)