2690e460f2ef668b808d5afe8817cd1ffbd94b0f
[linux-3.10.git] / fs / ext2 / super.c
1 /*
2  *  linux/fs/ext2/super.c
3  *
4  * Copyright (C) 1992, 1993, 1994, 1995
5  * Remy Card (card@masi.ibp.fr)
6  * Laboratoire MASI - Institut Blaise Pascal
7  * Universite Pierre et Marie Curie (Paris VI)
8  *
9  *  from
10  *
11  *  linux/fs/minix/inode.c
12  *
13  *  Copyright (C) 1991, 1992  Linus Torvalds
14  *
15  *  Big-endian to little-endian byte-swapping/bitmaps by
16  *        David S. Miller (davem@caip.rutgers.edu), 1995
17  */
18
19 #include <linux/module.h>
20 #include <linux/string.h>
21 #include <linux/fs.h>
22 #include <linux/slab.h>
23 #include <linux/init.h>
24 #include <linux/blkdev.h>
25 #include <linux/parser.h>
26 #include <linux/random.h>
27 #include <linux/buffer_head.h>
28 #include <linux/exportfs.h>
29 #include <linux/smp_lock.h>
30 #include <linux/vfs.h>
31 #include <linux/seq_file.h>
32 #include <linux/mount.h>
33 #include <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 dentry * dentry, 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 struct kmem_cache * ext2_inode_cachep;
140
141 static struct inode *ext2_alloc_inode(struct super_block *sb)
142 {
143         struct ext2_inode_info *ei;
144         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
145         if (!ei)
146                 return NULL;
147 #ifdef CONFIG_EXT2_FS_POSIX_ACL
148         ei->i_acl = EXT2_ACL_NOT_CACHED;
149         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
150 #endif
151         ei->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, struct kmem_cache * cachep, unsigned long flags)
161 {
162         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
163
164         rwlock_init(&ei->i_meta_lock);
165 #ifdef CONFIG_EXT2_FS_XATTR
166         init_rwsem(&ei->xattr_sem);
167 #endif
168         inode_init_once(&ei->vfs_inode);
169 }
170
171 static int init_inodecache(void)
172 {
173         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
174                                              sizeof(struct ext2_inode_info),
175                                              0, (SLAB_RECLAIM_ACCOUNT|
176                                                 SLAB_MEM_SPREAD),
177                                              init_once);
178         if (ext2_inode_cachep == NULL)
179                 return -ENOMEM;
180         return 0;
181 }
182
183 static void destroy_inodecache(void)
184 {
185         kmem_cache_destroy(ext2_inode_cachep);
186 }
187
188 static void ext2_clear_inode(struct inode *inode)
189 {
190 #ifdef CONFIG_EXT2_FS_POSIX_ACL
191         struct ext2_inode_info *ei = EXT2_I(inode);
192
193         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
194                 posix_acl_release(ei->i_acl);
195                 ei->i_acl = EXT2_ACL_NOT_CACHED;
196         }
197         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
198                 posix_acl_release(ei->i_default_acl);
199                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
200         }
201 #endif
202 }
203
204 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
205 {
206         struct ext2_sb_info *sbi = EXT2_SB(vfs->mnt_sb);
207
208         if (sbi->s_mount_opt & EXT2_MOUNT_GRPID)
209                 seq_puts(seq, ",grpid");
210
211 #if defined(CONFIG_QUOTA)
212         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
213                 seq_puts(seq, ",usrquota");
214
215         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
216                 seq_puts(seq, ",grpquota");
217 #endif
218
219 #if defined(CONFIG_EXT2_FS_XIP)
220         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
221                 seq_puts(seq, ",xip");
222 #endif
223
224         return 0;
225 }
226
227 #ifdef CONFIG_QUOTA
228 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
229 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
230 #endif
231
232 static const struct super_operations ext2_sops = {
233         .alloc_inode    = ext2_alloc_inode,
234         .destroy_inode  = ext2_destroy_inode,
235         .read_inode     = ext2_read_inode,
236         .write_inode    = ext2_write_inode,
237         .put_inode      = ext2_put_inode,
238         .delete_inode   = ext2_delete_inode,
239         .put_super      = ext2_put_super,
240         .write_super    = ext2_write_super,
241         .statfs         = ext2_statfs,
242         .remount_fs     = ext2_remount,
243         .clear_inode    = ext2_clear_inode,
244         .show_options   = ext2_show_options,
245 #ifdef CONFIG_QUOTA
246         .quota_read     = ext2_quota_read,
247         .quota_write    = ext2_quota_write,
248 #endif
249 };
250
251 static struct dentry *ext2_get_dentry(struct super_block *sb, void *vobjp)
252 {
253         __u32 *objp = vobjp;
254         unsigned long ino = objp[0];
255         __u32 generation = objp[1];
256         struct inode *inode;
257         struct dentry *result;
258
259         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
260                 return ERR_PTR(-ESTALE);
261         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
262                 return ERR_PTR(-ESTALE);
263
264         /* iget isn't really right if the inode is currently unallocated!!
265          * ext2_read_inode currently does appropriate checks, but
266          * it might be "neater" to call ext2_get_inode first and check
267          * if the inode is valid.....
268          */
269         inode = iget(sb, ino);
270         if (inode == NULL)
271                 return ERR_PTR(-ENOMEM);
272         if (is_bad_inode(inode) ||
273             (generation && inode->i_generation != generation)) {
274                 /* we didn't find the right inode.. */
275                 iput(inode);
276                 return ERR_PTR(-ESTALE);
277         }
278         /* now to find a dentry.
279          * If possible, get a well-connected one
280          */
281         result = d_alloc_anon(inode);
282         if (!result) {
283                 iput(inode);
284                 return ERR_PTR(-ENOMEM);
285         }
286         return result;
287 }
288
289 /* Yes, most of these are left as NULL!!
290  * A NULL value implies the default, which works with ext2-like file
291  * systems, but can be improved upon.
292  * Currently only get_parent is required.
293  */
294 static struct export_operations ext2_export_ops = {
295         .get_parent = ext2_get_parent,
296         .get_dentry = ext2_get_dentry,
297 };
298
299 static unsigned long get_sb_block(void **data)
300 {
301         unsigned long   sb_block;
302         char            *options = (char *) *data;
303
304         if (!options || strncmp(options, "sb=", 3) != 0)
305                 return 1;       /* Default location */
306         options += 3;
307         sb_block = simple_strtoul(options, &options, 0);
308         if (*options && *options != ',') {
309                 printk("EXT2-fs: Invalid sb specification: %s\n",
310                        (char *) *data);
311                 return 1;
312         }
313         if (*options == ',')
314                 options++;
315         *data = (void *) options;
316         return sb_block;
317 }
318
319 enum {
320         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
321         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
322         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
323         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
324         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
325         Opt_usrquota, Opt_grpquota
326 };
327
328 static match_table_t tokens = {
329         {Opt_bsd_df, "bsddf"},
330         {Opt_minix_df, "minixdf"},
331         {Opt_grpid, "grpid"},
332         {Opt_grpid, "bsdgroups"},
333         {Opt_nogrpid, "nogrpid"},
334         {Opt_nogrpid, "sysvgroups"},
335         {Opt_resgid, "resgid=%u"},
336         {Opt_resuid, "resuid=%u"},
337         {Opt_sb, "sb=%u"},
338         {Opt_err_cont, "errors=continue"},
339         {Opt_err_panic, "errors=panic"},
340         {Opt_err_ro, "errors=remount-ro"},
341         {Opt_nouid32, "nouid32"},
342         {Opt_nocheck, "check=none"},
343         {Opt_nocheck, "nocheck"},
344         {Opt_debug, "debug"},
345         {Opt_oldalloc, "oldalloc"},
346         {Opt_orlov, "orlov"},
347         {Opt_nobh, "nobh"},
348         {Opt_user_xattr, "user_xattr"},
349         {Opt_nouser_xattr, "nouser_xattr"},
350         {Opt_acl, "acl"},
351         {Opt_noacl, "noacl"},
352         {Opt_xip, "xip"},
353         {Opt_grpquota, "grpquota"},
354         {Opt_ignore, "noquota"},
355         {Opt_quota, "quota"},
356         {Opt_usrquota, "usrquota"},
357         {Opt_err, NULL}
358 };
359
360 static int parse_options (char * options,
361                           struct ext2_sb_info *sbi)
362 {
363         char * p;
364         substring_t args[MAX_OPT_ARGS];
365         int option;
366
367         if (!options)
368                 return 1;
369
370         while ((p = strsep (&options, ",")) != NULL) {
371                 int token;
372                 if (!*p)
373                         continue;
374
375                 token = match_token(p, tokens, args);
376                 switch (token) {
377                 case Opt_bsd_df:
378                         clear_opt (sbi->s_mount_opt, MINIX_DF);
379                         break;
380                 case Opt_minix_df:
381                         set_opt (sbi->s_mount_opt, MINIX_DF);
382                         break;
383                 case Opt_grpid:
384                         set_opt (sbi->s_mount_opt, GRPID);
385                         break;
386                 case Opt_nogrpid:
387                         clear_opt (sbi->s_mount_opt, GRPID);
388                         break;
389                 case Opt_resuid:
390                         if (match_int(&args[0], &option))
391                                 return 0;
392                         sbi->s_resuid = option;
393                         break;
394                 case Opt_resgid:
395                         if (match_int(&args[0], &option))
396                                 return 0;
397                         sbi->s_resgid = option;
398                         break;
399                 case Opt_sb:
400                         /* handled by get_sb_block() instead of here */
401                         /* *sb_block = match_int(&args[0]); */
402                         break;
403                 case Opt_err_panic:
404                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
405                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
406                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
407                         break;
408                 case Opt_err_ro:
409                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
410                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
411                         set_opt (sbi->s_mount_opt, ERRORS_RO);
412                         break;
413                 case Opt_err_cont:
414                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
415                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
416                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
417                         break;
418                 case Opt_nouid32:
419                         set_opt (sbi->s_mount_opt, NO_UID32);
420                         break;
421                 case Opt_nocheck:
422                         clear_opt (sbi->s_mount_opt, CHECK);
423                         break;
424                 case Opt_debug:
425                         set_opt (sbi->s_mount_opt, DEBUG);
426                         break;
427                 case Opt_oldalloc:
428                         set_opt (sbi->s_mount_opt, OLDALLOC);
429                         break;
430                 case Opt_orlov:
431                         clear_opt (sbi->s_mount_opt, OLDALLOC);
432                         break;
433                 case Opt_nobh:
434                         set_opt (sbi->s_mount_opt, NOBH);
435                         break;
436 #ifdef CONFIG_EXT2_FS_XATTR
437                 case Opt_user_xattr:
438                         set_opt (sbi->s_mount_opt, XATTR_USER);
439                         break;
440                 case Opt_nouser_xattr:
441                         clear_opt (sbi->s_mount_opt, XATTR_USER);
442                         break;
443 #else
444                 case Opt_user_xattr:
445                 case Opt_nouser_xattr:
446                         printk("EXT2 (no)user_xattr options not supported\n");
447                         break;
448 #endif
449 #ifdef CONFIG_EXT2_FS_POSIX_ACL
450                 case Opt_acl:
451                         set_opt(sbi->s_mount_opt, POSIX_ACL);
452                         break;
453                 case Opt_noacl:
454                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
455                         break;
456 #else
457                 case Opt_acl:
458                 case Opt_noacl:
459                         printk("EXT2 (no)acl options not supported\n");
460                         break;
461 #endif
462                 case Opt_xip:
463 #ifdef CONFIG_EXT2_FS_XIP
464                         set_opt (sbi->s_mount_opt, XIP);
465 #else
466                         printk("EXT2 xip option not supported\n");
467 #endif
468                         break;
469
470 #if defined(CONFIG_QUOTA)
471                 case Opt_quota:
472                 case Opt_usrquota:
473                         set_opt(sbi->s_mount_opt, USRQUOTA);
474                         break;
475
476                 case Opt_grpquota:
477                         set_opt(sbi->s_mount_opt, GRPQUOTA);
478                         break;
479 #else
480                 case Opt_quota:
481                 case Opt_usrquota:
482                 case Opt_grpquota:
483                         printk(KERN_ERR
484                                 "EXT2-fs: quota operations not supported.\n");
485
486                         break;
487 #endif
488
489                 case Opt_ignore:
490                         break;
491                 default:
492                         return 0;
493                 }
494         }
495         return 1;
496 }
497
498 static int ext2_setup_super (struct super_block * sb,
499                               struct ext2_super_block * es,
500                               int read_only)
501 {
502         int res = 0;
503         struct ext2_sb_info *sbi = EXT2_SB(sb);
504
505         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
506                 printk ("EXT2-fs warning: revision level too high, "
507                         "forcing read-only mode\n");
508                 res = MS_RDONLY;
509         }
510         if (read_only)
511                 return res;
512         if (!(sbi->s_mount_state & EXT2_VALID_FS))
513                 printk ("EXT2-fs warning: mounting unchecked fs, "
514                         "running e2fsck is recommended\n");
515         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
516                 printk ("EXT2-fs warning: mounting fs with errors, "
517                         "running e2fsck is recommended\n");
518         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
519                  le16_to_cpu(es->s_mnt_count) >=
520                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
521                 printk ("EXT2-fs warning: maximal mount count reached, "
522                         "running e2fsck is recommended\n");
523         else if (le32_to_cpu(es->s_checkinterval) &&
524                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
525                 printk ("EXT2-fs warning: checktime reached, "
526                         "running e2fsck is recommended\n");
527         if (!le16_to_cpu(es->s_max_mnt_count))
528                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
529         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
530         ext2_write_super(sb);
531         if (test_opt (sb, DEBUG))
532                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
533                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
534                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
535                         sbi->s_frag_size,
536                         sbi->s_groups_count,
537                         EXT2_BLOCKS_PER_GROUP(sb),
538                         EXT2_INODES_PER_GROUP(sb),
539                         sbi->s_mount_opt);
540         return res;
541 }
542
543 static int ext2_check_descriptors (struct super_block * sb)
544 {
545         int i;
546         int desc_block = 0;
547         struct ext2_sb_info *sbi = EXT2_SB(sb);
548         unsigned long first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
549         unsigned long last_block;
550         struct ext2_group_desc * gdp = NULL;
551
552         ext2_debug ("Checking group descriptors");
553
554         for (i = 0; i < sbi->s_groups_count; i++)
555         {
556                 if (i == sbi->s_groups_count - 1)
557                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
558                 else
559                         last_block = first_block +
560                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
561
562                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
563                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
564                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
565                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
566                 {
567                         ext2_error (sb, "ext2_check_descriptors",
568                                     "Block bitmap for group %d"
569                                     " not in group (block %lu)!",
570                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
571                         return 0;
572                 }
573                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
574                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
575                 {
576                         ext2_error (sb, "ext2_check_descriptors",
577                                     "Inode bitmap for group %d"
578                                     " not in group (block %lu)!",
579                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
580                         return 0;
581                 }
582                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
583                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
584                     last_block)
585                 {
586                         ext2_error (sb, "ext2_check_descriptors",
587                                     "Inode table for group %d"
588                                     " not in group (block %lu)!",
589                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
590                         return 0;
591                 }
592                 first_block += EXT2_BLOCKS_PER_GROUP(sb);
593                 gdp++;
594         }
595         return 1;
596 }
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         int err;
657
658         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
659         if (!sbi)
660                 return -ENOMEM;
661         sb->s_fs_info = sbi;
662
663         /*
664          * See what the current blocksize for the device is, and
665          * use that as the blocksize.  Otherwise (or if the blocksize
666          * is smaller than the default) use the default.
667          * This is important for devices that have a hardware
668          * sectorsize that is larger than the default.
669          */
670         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
671         if (!blocksize) {
672                 printk ("EXT2-fs: unable to set blocksize\n");
673                 goto failed_sbi;
674         }
675
676         /*
677          * If the superblock doesn't start on a hardware sector boundary,
678          * calculate the offset.  
679          */
680         if (blocksize != BLOCK_SIZE) {
681                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
682                 offset = (sb_block*BLOCK_SIZE) % blocksize;
683         } else {
684                 logic_sb_block = sb_block;
685         }
686
687         if (!(bh = sb_bread(sb, logic_sb_block))) {
688                 printk ("EXT2-fs: unable to read superblock\n");
689                 goto failed_sbi;
690         }
691         /*
692          * Note: s_es must be initialized as soon as possible because
693          *       some ext2 macro-instructions depend on its value
694          */
695         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
696         sbi->s_es = es;
697         sb->s_magic = le16_to_cpu(es->s_magic);
698
699         if (sb->s_magic != EXT2_SUPER_MAGIC)
700                 goto cantfind_ext2;
701
702         /* Set defaults before we parse the mount options */
703         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
704         if (def_mount_opts & EXT2_DEFM_DEBUG)
705                 set_opt(sbi->s_mount_opt, DEBUG);
706         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
707                 set_opt(sbi->s_mount_opt, GRPID);
708         if (def_mount_opts & EXT2_DEFM_UID16)
709                 set_opt(sbi->s_mount_opt, NO_UID32);
710 #ifdef CONFIG_EXT2_FS_XATTR
711         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
712                 set_opt(sbi->s_mount_opt, XATTR_USER);
713 #endif
714 #ifdef CONFIG_EXT2_FS_POSIX_ACL
715         if (def_mount_opts & EXT2_DEFM_ACL)
716                 set_opt(sbi->s_mount_opt, POSIX_ACL);
717 #endif
718         
719         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
720                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
721         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
722                 set_opt(sbi->s_mount_opt, ERRORS_RO);
723         else
724                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
725
726         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
727         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
728         
729         if (!parse_options ((char *) data, sbi))
730                 goto failed_mount;
731
732         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
733                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
734                  MS_POSIXACL : 0);
735
736         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
737                                     EXT2_MOUNT_XIP if not */
738
739         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
740             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
741              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
742              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
743                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
744                        "running e2fsck is recommended\n");
745         /*
746          * Check feature flags regardless of the revision level, since we
747          * previously didn't change the revision level when setting the flags,
748          * so there is a chance incompat flags are set on a rev 0 filesystem.
749          */
750         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
751         if (features) {
752                 printk("EXT2-fs: %s: couldn't mount because of "
753                        "unsupported optional features (%x).\n",
754                        sb->s_id, le32_to_cpu(features));
755                 goto failed_mount;
756         }
757         if (!(sb->s_flags & MS_RDONLY) &&
758             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
759                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
760                        "unsupported optional features (%x).\n",
761                        sb->s_id, le32_to_cpu(features));
762                 goto failed_mount;
763         }
764
765         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
766
767         if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
768                                   (sb->s_blocksize != blocksize))) {
769                 if (!silent)
770                         printk("XIP: Unsupported blocksize\n");
771                 goto failed_mount;
772         }
773
774         /* If the blocksize doesn't match, re-read the thing.. */
775         if (sb->s_blocksize != blocksize) {
776                 brelse(bh);
777
778                 if (!sb_set_blocksize(sb, blocksize)) {
779                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
780                         goto failed_sbi;
781                 }
782
783                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
784                 offset = (sb_block*BLOCK_SIZE) % blocksize;
785                 bh = sb_bread(sb, logic_sb_block);
786                 if(!bh) {
787                         printk("EXT2-fs: Couldn't read superblock on "
788                                "2nd try.\n");
789                         goto failed_sbi;
790                 }
791                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
792                 sbi->s_es = es;
793                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
794                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
795                         goto failed_mount;
796                 }
797         }
798
799         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
800
801         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
802                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
803                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
804         } else {
805                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
806                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
807                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
808                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
809                     (sbi->s_inode_size > blocksize)) {
810                         printk ("EXT2-fs: unsupported inode size: %d\n",
811                                 sbi->s_inode_size);
812                         goto failed_mount;
813                 }
814         }
815
816         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
817                                    le32_to_cpu(es->s_log_frag_size);
818         if (sbi->s_frag_size == 0)
819                 goto cantfind_ext2;
820         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
821
822         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
823         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
824         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
825
826         if (EXT2_INODE_SIZE(sb) == 0)
827                 goto cantfind_ext2;
828         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
829         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
830                 goto cantfind_ext2;
831         sbi->s_itb_per_group = sbi->s_inodes_per_group /
832                                         sbi->s_inodes_per_block;
833         sbi->s_desc_per_block = sb->s_blocksize /
834                                         sizeof (struct ext2_group_desc);
835         sbi->s_sbh = bh;
836         sbi->s_mount_state = le16_to_cpu(es->s_state);
837         sbi->s_addr_per_block_bits =
838                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
839         sbi->s_desc_per_block_bits =
840                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
841
842         if (sb->s_magic != EXT2_SUPER_MAGIC)
843                 goto cantfind_ext2;
844
845         if (sb->s_blocksize != bh->b_size) {
846                 if (!silent)
847                         printk ("VFS: Unsupported blocksize on dev "
848                                 "%s.\n", sb->s_id);
849                 goto failed_mount;
850         }
851
852         if (sb->s_blocksize != sbi->s_frag_size) {
853                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
854                         sbi->s_frag_size, sb->s_blocksize);
855                 goto failed_mount;
856         }
857
858         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
859                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
860                         sbi->s_blocks_per_group);
861                 goto failed_mount;
862         }
863         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
864                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
865                         sbi->s_frags_per_group);
866                 goto failed_mount;
867         }
868         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
869                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
870                         sbi->s_inodes_per_group);
871                 goto failed_mount;
872         }
873
874         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
875                 goto cantfind_ext2;
876         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
877                                 le32_to_cpu(es->s_first_data_block) - 1)
878                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
879         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
880                    EXT2_DESC_PER_BLOCK(sb);
881         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
882         if (sbi->s_group_desc == NULL) {
883                 printk ("EXT2-fs: not enough memory\n");
884                 goto failed_mount;
885         }
886         bgl_lock_init(&sbi->s_blockgroup_lock);
887         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
888         if (!sbi->s_debts) {
889                 printk ("EXT2-fs: not enough memory\n");
890                 goto failed_mount_group_desc;
891         }
892         for (i = 0; i < db_count; i++) {
893                 block = descriptor_loc(sb, logic_sb_block, i);
894                 sbi->s_group_desc[i] = sb_bread(sb, block);
895                 if (!sbi->s_group_desc[i]) {
896                         for (j = 0; j < i; j++)
897                                 brelse (sbi->s_group_desc[j]);
898                         printk ("EXT2-fs: unable to read group descriptors\n");
899                         goto failed_mount_group_desc;
900                 }
901         }
902         if (!ext2_check_descriptors (sb)) {
903                 printk ("EXT2-fs: group descriptors corrupted!\n");
904                 goto failed_mount2;
905         }
906         sbi->s_gdb_count = db_count;
907         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
908         spin_lock_init(&sbi->s_next_gen_lock);
909
910         err = percpu_counter_init(&sbi->s_freeblocks_counter,
911                                 ext2_count_free_blocks(sb));
912         if (!err) {
913                 err = percpu_counter_init(&sbi->s_freeinodes_counter,
914                                 ext2_count_free_inodes(sb));
915         }
916         if (!err) {
917                 err = percpu_counter_init(&sbi->s_dirs_counter,
918                                 ext2_count_dirs(sb));
919         }
920         if (err) {
921                 printk(KERN_ERR "EXT2-fs: insufficient memory\n");
922                 goto failed_mount3;
923         }
924         /*
925          * set up enough so that it can read an inode
926          */
927         sb->s_op = &ext2_sops;
928         sb->s_export_op = &ext2_export_ops;
929         sb->s_xattr = ext2_xattr_handlers;
930         root = iget(sb, EXT2_ROOT_INO);
931         sb->s_root = d_alloc_root(root);
932         if (!sb->s_root) {
933                 iput(root);
934                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
935                 goto failed_mount3;
936         }
937         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
938                 dput(sb->s_root);
939                 sb->s_root = NULL;
940                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
941                 goto failed_mount3;
942         }
943         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
944                 ext2_warning(sb, __FUNCTION__,
945                         "mounting ext3 filesystem as ext2");
946         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
947         return 0;
948
949 cantfind_ext2:
950         if (!silent)
951                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
952                        sb->s_id);
953         goto failed_mount;
954 failed_mount3:
955         percpu_counter_destroy(&sbi->s_freeblocks_counter);
956         percpu_counter_destroy(&sbi->s_freeinodes_counter);
957         percpu_counter_destroy(&sbi->s_dirs_counter);
958 failed_mount2:
959         for (i = 0; i < db_count; i++)
960                 brelse(sbi->s_group_desc[i]);
961 failed_mount_group_desc:
962         kfree(sbi->s_group_desc);
963         kfree(sbi->s_debts);
964 failed_mount:
965         brelse(bh);
966 failed_sbi:
967         sb->s_fs_info = NULL;
968         kfree(sbi);
969         return -EINVAL;
970 }
971
972 static void ext2_commit_super (struct super_block * sb,
973                                struct ext2_super_block * es)
974 {
975         es->s_wtime = cpu_to_le32(get_seconds());
976         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
977         sb->s_dirt = 0;
978 }
979
980 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
981 {
982         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
983         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
984         es->s_wtime = cpu_to_le32(get_seconds());
985         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
986         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
987         sb->s_dirt = 0;
988 }
989
990 /*
991  * In the second extended file system, it is not necessary to
992  * write the super block since we use a mapping of the
993  * disk super block in a buffer.
994  *
995  * However, this function is still used to set the fs valid
996  * flags to 0.  We need to set this flag to 0 since the fs
997  * may have been checked while mounted and e2fsck may have
998  * set s_state to EXT2_VALID_FS after some corrections.
999  */
1000
1001 void ext2_write_super (struct super_block * sb)
1002 {
1003         struct ext2_super_block * es;
1004         lock_kernel();
1005         if (!(sb->s_flags & MS_RDONLY)) {
1006                 es = EXT2_SB(sb)->s_es;
1007
1008                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
1009                         ext2_debug ("setting valid to 0\n");
1010                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
1011                                                   ~EXT2_VALID_FS);
1012                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1013                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1014                         es->s_mtime = cpu_to_le32(get_seconds());
1015                         ext2_sync_super(sb, es);
1016                 } else
1017                         ext2_commit_super (sb, es);
1018         }
1019         sb->s_dirt = 0;
1020         unlock_kernel();
1021 }
1022
1023 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1024 {
1025         struct ext2_sb_info * sbi = EXT2_SB(sb);
1026         struct ext2_super_block * es;
1027         unsigned long old_mount_opt = sbi->s_mount_opt;
1028         struct ext2_mount_options old_opts;
1029         unsigned long old_sb_flags;
1030         int err;
1031
1032         /* Store the old options */
1033         old_sb_flags = sb->s_flags;
1034         old_opts.s_mount_opt = sbi->s_mount_opt;
1035         old_opts.s_resuid = sbi->s_resuid;
1036         old_opts.s_resgid = sbi->s_resgid;
1037
1038         /*
1039          * Allow the "check" option to be passed as a remount option.
1040          */
1041         if (!parse_options (data, sbi)) {
1042                 err = -EINVAL;
1043                 goto restore_opts;
1044         }
1045
1046         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1047                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1048
1049         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1050                                     EXT2_MOUNT_XIP if not */
1051
1052         if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1053                 printk("XIP: Unsupported blocksize\n");
1054                 err = -EINVAL;
1055                 goto restore_opts;
1056         }
1057
1058         es = sbi->s_es;
1059         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1060             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1061             invalidate_inodes(sb))
1062                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1063                              "xip remain in cache (no functional problem)");
1064         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1065                 return 0;
1066         if (*flags & MS_RDONLY) {
1067                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1068                     !(sbi->s_mount_state & EXT2_VALID_FS))
1069                         return 0;
1070                 /*
1071                  * OK, we are remounting a valid rw partition rdonly, so set
1072                  * the rdonly flag and then mark the partition as valid again.
1073                  */
1074                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1075                 es->s_mtime = cpu_to_le32(get_seconds());
1076         } else {
1077                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1078                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1079                 if (ret) {
1080                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1081                                "unsupported optional features (%x).\n",
1082                                sb->s_id, le32_to_cpu(ret));
1083                         err = -EROFS;
1084                         goto restore_opts;
1085                 }
1086                 /*
1087                  * Mounting a RDONLY partition read-write, so reread and
1088                  * store the current valid flag.  (It may have been changed
1089                  * by e2fsck since we originally mounted the partition.)
1090                  */
1091                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1092                 if (!ext2_setup_super (sb, es, 0))
1093                         sb->s_flags &= ~MS_RDONLY;
1094         }
1095         ext2_sync_super(sb, es);
1096         return 0;
1097 restore_opts:
1098         sbi->s_mount_opt = old_opts.s_mount_opt;
1099         sbi->s_resuid = old_opts.s_resuid;
1100         sbi->s_resgid = old_opts.s_resgid;
1101         sb->s_flags = old_sb_flags;
1102         return err;
1103 }
1104
1105 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1106 {
1107         struct super_block *sb = dentry->d_sb;
1108         struct ext2_sb_info *sbi = EXT2_SB(sb);
1109         struct ext2_super_block *es = sbi->s_es;
1110         u64 fsid;
1111
1112         if (test_opt (sb, MINIX_DF))
1113                 sbi->s_overhead_last = 0;
1114         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1115                 unsigned long i, overhead = 0;
1116                 smp_rmb();
1117
1118                 /*
1119                  * Compute the overhead (FS structures). This is constant
1120                  * for a given filesystem unless the number of block groups
1121                  * changes so we cache the previous value until it does.
1122                  */
1123
1124                 /*
1125                  * All of the blocks before first_data_block are
1126                  * overhead
1127                  */
1128                 overhead = le32_to_cpu(es->s_first_data_block);
1129
1130                 /*
1131                  * Add the overhead attributed to the superblock and
1132                  * block group descriptors.  If the sparse superblocks
1133                  * feature is turned on, then not all groups have this.
1134                  */
1135                 for (i = 0; i < sbi->s_groups_count; i++)
1136                         overhead += ext2_bg_has_super(sb, i) +
1137                                 ext2_bg_num_gdb(sb, i);
1138
1139                 /*
1140                  * Every block group has an inode bitmap, a block
1141                  * bitmap, and an inode table.
1142                  */
1143                 overhead += (sbi->s_groups_count *
1144                              (2 + sbi->s_itb_per_group));
1145                 sbi->s_overhead_last = overhead;
1146                 smp_wmb();
1147                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1148         }
1149
1150         buf->f_type = EXT2_SUPER_MAGIC;
1151         buf->f_bsize = sb->s_blocksize;
1152         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1153         buf->f_bfree = ext2_count_free_blocks(sb);
1154         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1155         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1156         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1157                 buf->f_bavail = 0;
1158         buf->f_files = le32_to_cpu(es->s_inodes_count);
1159         buf->f_ffree = ext2_count_free_inodes(sb);
1160         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1161         buf->f_namelen = EXT2_NAME_LEN;
1162         fsid = le64_to_cpup((void *)es->s_uuid) ^
1163                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1164         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1165         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1166         return 0;
1167 }
1168
1169 static int ext2_get_sb(struct file_system_type *fs_type,
1170         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1171 {
1172         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1173 }
1174
1175 #ifdef CONFIG_QUOTA
1176
1177 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1178  * acquiring the locks... As quota files are never truncated and quota code
1179  * itself serializes the operations (and noone else should touch the files)
1180  * we don't have to be afraid of races */
1181 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1182                                size_t len, loff_t off)
1183 {
1184         struct inode *inode = sb_dqopt(sb)->files[type];
1185         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1186         int err = 0;
1187         int offset = off & (sb->s_blocksize - 1);
1188         int tocopy;
1189         size_t toread;
1190         struct buffer_head tmp_bh;
1191         struct buffer_head *bh;
1192         loff_t i_size = i_size_read(inode);
1193
1194         if (off > i_size)
1195                 return 0;
1196         if (off+len > i_size)
1197                 len = i_size-off;
1198         toread = len;
1199         while (toread > 0) {
1200                 tocopy = sb->s_blocksize - offset < toread ?
1201                                 sb->s_blocksize - offset : toread;
1202
1203                 tmp_bh.b_state = 0;
1204                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1205                 if (err)
1206                         return err;
1207                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1208                         memset(data, 0, tocopy);
1209                 else {
1210                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1211                         if (!bh)
1212                                 return -EIO;
1213                         memcpy(data, bh->b_data+offset, tocopy);
1214                         brelse(bh);
1215                 }
1216                 offset = 0;
1217                 toread -= tocopy;
1218                 data += tocopy;
1219                 blk++;
1220         }
1221         return len;
1222 }
1223
1224 /* Write to quotafile */
1225 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1226                                 const char *data, size_t len, loff_t off)
1227 {
1228         struct inode *inode = sb_dqopt(sb)->files[type];
1229         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1230         int err = 0;
1231         int offset = off & (sb->s_blocksize - 1);
1232         int tocopy;
1233         size_t towrite = len;
1234         struct buffer_head tmp_bh;
1235         struct buffer_head *bh;
1236
1237         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1238         while (towrite > 0) {
1239                 tocopy = sb->s_blocksize - offset < towrite ?
1240                                 sb->s_blocksize - offset : towrite;
1241
1242                 tmp_bh.b_state = 0;
1243                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1244                 if (err)
1245                         goto out;
1246                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1247                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1248                 else
1249                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1250                 if (!bh) {
1251                         err = -EIO;
1252                         goto out;
1253                 }
1254                 lock_buffer(bh);
1255                 memcpy(bh->b_data+offset, data, tocopy);
1256                 flush_dcache_page(bh->b_page);
1257                 set_buffer_uptodate(bh);
1258                 mark_buffer_dirty(bh);
1259                 unlock_buffer(bh);
1260                 brelse(bh);
1261                 offset = 0;
1262                 towrite -= tocopy;
1263                 data += tocopy;
1264                 blk++;
1265         }
1266 out:
1267         if (len == towrite)
1268                 return err;
1269         if (inode->i_size < off+len-towrite)
1270                 i_size_write(inode, off+len-towrite);
1271         inode->i_version++;
1272         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1273         mark_inode_dirty(inode);
1274         mutex_unlock(&inode->i_mutex);
1275         return len - towrite;
1276 }
1277
1278 #endif
1279
1280 static struct file_system_type ext2_fs_type = {
1281         .owner          = THIS_MODULE,
1282         .name           = "ext2",
1283         .get_sb         = ext2_get_sb,
1284         .kill_sb        = kill_block_super,
1285         .fs_flags       = FS_REQUIRES_DEV,
1286 };
1287
1288 static int __init init_ext2_fs(void)
1289 {
1290         int err = init_ext2_xattr();
1291         if (err)
1292                 return err;
1293         err = init_inodecache();
1294         if (err)
1295                 goto out1;
1296         err = register_filesystem(&ext2_fs_type);
1297         if (err)
1298                 goto out;
1299         return 0;
1300 out:
1301         destroy_inodecache();
1302 out1:
1303         exit_ext2_xattr();
1304         return err;
1305 }
1306
1307 static void __exit exit_ext2_fs(void)
1308 {
1309         unregister_filesystem(&ext2_fs_type);
1310         destroy_inodecache();
1311         exit_ext2_xattr();
1312 }
1313
1314 module_init(init_ext2_fs)
1315 module_exit(exit_ext2_fs)