[PATCH] fix umask when noACL kernel meets extN tuned for ACLs
[linux-drm-fsl-dcu.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/smp_lock.h>
29 #include <linux/vfs.h>
30 #include <linux/seq_file.h>
31 #include <linux/mount.h>
32 #include <asm/uaccess.h>
33 #include "ext2.h"
34 #include "xattr.h"
35 #include "acl.h"
36 #include "xip.h"
37
38 static void ext2_sync_super(struct super_block *sb,
39                             struct ext2_super_block *es);
40 static int ext2_remount (struct super_block * sb, int * flags, char * data);
41 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
42
43 void ext2_error (struct super_block * sb, const char * function,
44                  const char * fmt, ...)
45 {
46         va_list args;
47         struct ext2_sb_info *sbi = EXT2_SB(sb);
48         struct ext2_super_block *es = sbi->s_es;
49
50         if (!(sb->s_flags & MS_RDONLY)) {
51                 sbi->s_mount_state |= EXT2_ERROR_FS;
52                 es->s_state =
53                         cpu_to_le16(le16_to_cpu(es->s_state) | EXT2_ERROR_FS);
54                 ext2_sync_super(sb, es);
55         }
56
57         va_start(args, fmt);
58         printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
59         vprintk(fmt, args);
60         printk("\n");
61         va_end(args);
62
63         if (test_opt(sb, ERRORS_PANIC))
64                 panic("EXT2-fs panic from previous error\n");
65         if (test_opt(sb, ERRORS_RO)) {
66                 printk("Remounting filesystem read-only\n");
67                 sb->s_flags |= MS_RDONLY;
68         }
69 }
70
71 void ext2_warning (struct super_block * sb, const char * function,
72                    const char * fmt, ...)
73 {
74         va_list args;
75
76         va_start(args, fmt);
77         printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
78                sb->s_id, function);
79         vprintk(fmt, args);
80         printk("\n");
81         va_end(args);
82 }
83
84 void ext2_update_dynamic_rev(struct super_block *sb)
85 {
86         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
87
88         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
89                 return;
90
91         ext2_warning(sb, __FUNCTION__,
92                      "updating to rev %d because of new feature flag, "
93                      "running e2fsck is recommended",
94                      EXT2_DYNAMIC_REV);
95
96         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
97         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
98         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
99         /* leave es->s_feature_*compat flags alone */
100         /* es->s_uuid will be set by e2fsck if empty */
101
102         /*
103          * The rest of the superblock fields should be zero, and if not it
104          * means they are likely already in use, so leave them alone.  We
105          * can leave it up to e2fsck to clean up any inconsistencies there.
106          */
107 }
108
109 static void ext2_put_super (struct super_block * sb)
110 {
111         int db_count;
112         int i;
113         struct ext2_sb_info *sbi = EXT2_SB(sb);
114
115         ext2_xattr_put_super(sb);
116         if (!(sb->s_flags & MS_RDONLY)) {
117                 struct ext2_super_block *es = sbi->s_es;
118
119                 es->s_state = cpu_to_le16(sbi->s_mount_state);
120                 ext2_sync_super(sb, es);
121         }
122         db_count = sbi->s_gdb_count;
123         for (i = 0; i < db_count; i++)
124                 if (sbi->s_group_desc[i])
125                         brelse (sbi->s_group_desc[i]);
126         kfree(sbi->s_group_desc);
127         kfree(sbi->s_debts);
128         percpu_counter_destroy(&sbi->s_freeblocks_counter);
129         percpu_counter_destroy(&sbi->s_freeinodes_counter);
130         percpu_counter_destroy(&sbi->s_dirs_counter);
131         brelse (sbi->s_sbh);
132         sb->s_fs_info = NULL;
133         kfree(sbi);
134
135         return;
136 }
137
138 static struct kmem_cache * ext2_inode_cachep;
139
140 static struct inode *ext2_alloc_inode(struct super_block *sb)
141 {
142         struct ext2_inode_info *ei;
143         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
144         if (!ei)
145                 return NULL;
146 #ifdef CONFIG_EXT2_FS_POSIX_ACL
147         ei->i_acl = EXT2_ACL_NOT_CACHED;
148         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
149 #endif
150         ei->vfs_inode.i_version = 1;
151         return &ei->vfs_inode;
152 }
153
154 static void ext2_destroy_inode(struct inode *inode)
155 {
156         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
157 }
158
159 static void init_once(void * foo, struct kmem_cache * cachep, unsigned long flags)
160 {
161         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
162
163         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
164             SLAB_CTOR_CONSTRUCTOR) {
165                 rwlock_init(&ei->i_meta_lock);
166 #ifdef CONFIG_EXT2_FS_XATTR
167                 init_rwsem(&ei->xattr_sem);
168 #endif
169                 inode_init_once(&ei->vfs_inode);
170         }
171 }
172  
173 static int init_inodecache(void)
174 {
175         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
176                                              sizeof(struct ext2_inode_info),
177                                              0, (SLAB_RECLAIM_ACCOUNT|
178                                                 SLAB_MEM_SPREAD),
179                                              init_once, NULL);
180         if (ext2_inode_cachep == NULL)
181                 return -ENOMEM;
182         return 0;
183 }
184
185 static void destroy_inodecache(void)
186 {
187         kmem_cache_destroy(ext2_inode_cachep);
188 }
189
190 static void ext2_clear_inode(struct inode *inode)
191 {
192 #ifdef CONFIG_EXT2_FS_POSIX_ACL
193         struct ext2_inode_info *ei = EXT2_I(inode);
194
195         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
196                 posix_acl_release(ei->i_acl);
197                 ei->i_acl = EXT2_ACL_NOT_CACHED;
198         }
199         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
200                 posix_acl_release(ei->i_default_acl);
201                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
202         }
203 #endif
204 }
205
206 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
207 {
208         struct ext2_sb_info *sbi = EXT2_SB(vfs->mnt_sb);
209
210         if (sbi->s_mount_opt & EXT2_MOUNT_GRPID)
211                 seq_puts(seq, ",grpid");
212
213 #if defined(CONFIG_QUOTA)
214         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
215                 seq_puts(seq, ",usrquota");
216
217         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
218                 seq_puts(seq, ",grpquota");
219 #endif
220
221 #if defined(CONFIG_EXT2_FS_XIP)
222         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
223                 seq_puts(seq, ",xip");
224 #endif
225
226         return 0;
227 }
228
229 #ifdef CONFIG_QUOTA
230 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
231 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
232 #endif
233
234 static struct super_operations ext2_sops = {
235         .alloc_inode    = ext2_alloc_inode,
236         .destroy_inode  = ext2_destroy_inode,
237         .read_inode     = ext2_read_inode,
238         .write_inode    = ext2_write_inode,
239         .put_inode      = ext2_put_inode,
240         .delete_inode   = ext2_delete_inode,
241         .put_super      = ext2_put_super,
242         .write_super    = ext2_write_super,
243         .statfs         = ext2_statfs,
244         .remount_fs     = ext2_remount,
245         .clear_inode    = ext2_clear_inode,
246         .show_options   = ext2_show_options,
247 #ifdef CONFIG_QUOTA
248         .quota_read     = ext2_quota_read,
249         .quota_write    = ext2_quota_write,
250 #endif
251 };
252
253 static struct dentry *ext2_get_dentry(struct super_block *sb, void *vobjp)
254 {
255         __u32 *objp = vobjp;
256         unsigned long ino = objp[0];
257         __u32 generation = objp[1];
258         struct inode *inode;
259         struct dentry *result;
260
261         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
262                 return ERR_PTR(-ESTALE);
263         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
264                 return ERR_PTR(-ESTALE);
265
266         /* iget isn't really right if the inode is currently unallocated!!
267          * ext2_read_inode currently does appropriate checks, but
268          * it might be "neater" to call ext2_get_inode first and check
269          * if the inode is valid.....
270          */
271         inode = iget(sb, ino);
272         if (inode == NULL)
273                 return ERR_PTR(-ENOMEM);
274         if (is_bad_inode(inode) ||
275             (generation && inode->i_generation != generation)) {
276                 /* we didn't find the right inode.. */
277                 iput(inode);
278                 return ERR_PTR(-ESTALE);
279         }
280         /* now to find a dentry.
281          * If possible, get a well-connected one
282          */
283         result = d_alloc_anon(inode);
284         if (!result) {
285                 iput(inode);
286                 return ERR_PTR(-ENOMEM);
287         }
288         return result;
289 }
290
291 /* Yes, most of these are left as NULL!!
292  * A NULL value implies the default, which works with ext2-like file
293  * systems, but can be improved upon.
294  * Currently only get_parent is required.
295  */
296 static struct export_operations ext2_export_ops = {
297         .get_parent = ext2_get_parent,
298         .get_dentry = ext2_get_dentry,
299 };
300
301 static unsigned long get_sb_block(void **data)
302 {
303         unsigned long   sb_block;
304         char            *options = (char *) *data;
305
306         if (!options || strncmp(options, "sb=", 3) != 0)
307                 return 1;       /* Default location */
308         options += 3;
309         sb_block = simple_strtoul(options, &options, 0);
310         if (*options && *options != ',') {
311                 printk("EXT2-fs: Invalid sb specification: %s\n",
312                        (char *) *data);
313                 return 1;
314         }
315         if (*options == ',')
316                 options++;
317         *data = (void *) options;
318         return sb_block;
319 }
320
321 enum {
322         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
323         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
324         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
325         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
326         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
327         Opt_usrquota, Opt_grpquota
328 };
329
330 static match_table_t tokens = {
331         {Opt_bsd_df, "bsddf"},
332         {Opt_minix_df, "minixdf"},
333         {Opt_grpid, "grpid"},
334         {Opt_grpid, "bsdgroups"},
335         {Opt_nogrpid, "nogrpid"},
336         {Opt_nogrpid, "sysvgroups"},
337         {Opt_resgid, "resgid=%u"},
338         {Opt_resuid, "resuid=%u"},
339         {Opt_sb, "sb=%u"},
340         {Opt_err_cont, "errors=continue"},
341         {Opt_err_panic, "errors=panic"},
342         {Opt_err_ro, "errors=remount-ro"},
343         {Opt_nouid32, "nouid32"},
344         {Opt_nocheck, "check=none"},
345         {Opt_nocheck, "nocheck"},
346         {Opt_debug, "debug"},
347         {Opt_oldalloc, "oldalloc"},
348         {Opt_orlov, "orlov"},
349         {Opt_nobh, "nobh"},
350         {Opt_user_xattr, "user_xattr"},
351         {Opt_nouser_xattr, "nouser_xattr"},
352         {Opt_acl, "acl"},
353         {Opt_noacl, "noacl"},
354         {Opt_xip, "xip"},
355         {Opt_grpquota, "grpquota"},
356         {Opt_ignore, "noquota"},
357         {Opt_quota, "quota"},
358         {Opt_usrquota, "usrquota"},
359         {Opt_err, NULL}
360 };
361
362 static int parse_options (char * options,
363                           struct ext2_sb_info *sbi)
364 {
365         char * p;
366         substring_t args[MAX_OPT_ARGS];
367         int option;
368
369         if (!options)
370                 return 1;
371
372         while ((p = strsep (&options, ",")) != NULL) {
373                 int token;
374                 if (!*p)
375                         continue;
376
377                 token = match_token(p, tokens, args);
378                 switch (token) {
379                 case Opt_bsd_df:
380                         clear_opt (sbi->s_mount_opt, MINIX_DF);
381                         break;
382                 case Opt_minix_df:
383                         set_opt (sbi->s_mount_opt, MINIX_DF);
384                         break;
385                 case Opt_grpid:
386                         set_opt (sbi->s_mount_opt, GRPID);
387                         break;
388                 case Opt_nogrpid:
389                         clear_opt (sbi->s_mount_opt, GRPID);
390                         break;
391                 case Opt_resuid:
392                         if (match_int(&args[0], &option))
393                                 return 0;
394                         sbi->s_resuid = option;
395                         break;
396                 case Opt_resgid:
397                         if (match_int(&args[0], &option))
398                                 return 0;
399                         sbi->s_resgid = option;
400                         break;
401                 case Opt_sb:
402                         /* handled by get_sb_block() instead of here */
403                         /* *sb_block = match_int(&args[0]); */
404                         break;
405                 case Opt_err_panic:
406                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
407                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
408                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
409                         break;
410                 case Opt_err_ro:
411                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
412                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
413                         set_opt (sbi->s_mount_opt, ERRORS_RO);
414                         break;
415                 case Opt_err_cont:
416                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
417                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
418                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
419                         break;
420                 case Opt_nouid32:
421                         set_opt (sbi->s_mount_opt, NO_UID32);
422                         break;
423                 case Opt_nocheck:
424                         clear_opt (sbi->s_mount_opt, CHECK);
425                         break;
426                 case Opt_debug:
427                         set_opt (sbi->s_mount_opt, DEBUG);
428                         break;
429                 case Opt_oldalloc:
430                         set_opt (sbi->s_mount_opt, OLDALLOC);
431                         break;
432                 case Opt_orlov:
433                         clear_opt (sbi->s_mount_opt, OLDALLOC);
434                         break;
435                 case Opt_nobh:
436                         set_opt (sbi->s_mount_opt, NOBH);
437                         break;
438 #ifdef CONFIG_EXT2_FS_XATTR
439                 case Opt_user_xattr:
440                         set_opt (sbi->s_mount_opt, XATTR_USER);
441                         break;
442                 case Opt_nouser_xattr:
443                         clear_opt (sbi->s_mount_opt, XATTR_USER);
444                         break;
445 #else
446                 case Opt_user_xattr:
447                 case Opt_nouser_xattr:
448                         printk("EXT2 (no)user_xattr options not supported\n");
449                         break;
450 #endif
451 #ifdef CONFIG_EXT2_FS_POSIX_ACL
452                 case Opt_acl:
453                         set_opt(sbi->s_mount_opt, POSIX_ACL);
454                         break;
455                 case Opt_noacl:
456                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
457                         break;
458 #else
459                 case Opt_acl:
460                 case Opt_noacl:
461                         printk("EXT2 (no)acl options not supported\n");
462                         break;
463 #endif
464                 case Opt_xip:
465 #ifdef CONFIG_EXT2_FS_XIP
466                         set_opt (sbi->s_mount_opt, XIP);
467 #else
468                         printk("EXT2 xip option not supported\n");
469 #endif
470                         break;
471
472 #if defined(CONFIG_QUOTA)
473                 case Opt_quota:
474                 case Opt_usrquota:
475                         set_opt(sbi->s_mount_opt, USRQUOTA);
476                         break;
477
478                 case Opt_grpquota:
479                         set_opt(sbi->s_mount_opt, GRPQUOTA);
480                         break;
481 #else
482                 case Opt_quota:
483                 case Opt_usrquota:
484                 case Opt_grpquota:
485                         printk(KERN_ERR
486                                 "EXT2-fs: quota operations not supported.\n");
487
488                         break;
489 #endif
490
491                 case Opt_ignore:
492                         break;
493                 default:
494                         return 0;
495                 }
496         }
497         return 1;
498 }
499
500 static int ext2_setup_super (struct super_block * sb,
501                               struct ext2_super_block * es,
502                               int read_only)
503 {
504         int res = 0;
505         struct ext2_sb_info *sbi = EXT2_SB(sb);
506
507         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
508                 printk ("EXT2-fs warning: revision level too high, "
509                         "forcing read-only mode\n");
510                 res = MS_RDONLY;
511         }
512         if (read_only)
513                 return res;
514         if (!(sbi->s_mount_state & EXT2_VALID_FS))
515                 printk ("EXT2-fs warning: mounting unchecked fs, "
516                         "running e2fsck is recommended\n");
517         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
518                 printk ("EXT2-fs warning: mounting fs with errors, "
519                         "running e2fsck is recommended\n");
520         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
521                  le16_to_cpu(es->s_mnt_count) >=
522                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
523                 printk ("EXT2-fs warning: maximal mount count reached, "
524                         "running e2fsck is recommended\n");
525         else if (le32_to_cpu(es->s_checkinterval) &&
526                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
527                 printk ("EXT2-fs warning: checktime reached, "
528                         "running e2fsck is recommended\n");
529         if (!le16_to_cpu(es->s_max_mnt_count))
530                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
531         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
532         ext2_write_super(sb);
533         if (test_opt (sb, DEBUG))
534                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
535                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
536                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
537                         sbi->s_frag_size,
538                         sbi->s_groups_count,
539                         EXT2_BLOCKS_PER_GROUP(sb),
540                         EXT2_INODES_PER_GROUP(sb),
541                         sbi->s_mount_opt);
542         return res;
543 }
544
545 static int ext2_check_descriptors (struct super_block * sb)
546 {
547         int i;
548         int desc_block = 0;
549         struct ext2_sb_info *sbi = EXT2_SB(sb);
550         unsigned long first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
551         unsigned long last_block;
552         struct ext2_group_desc * gdp = NULL;
553
554         ext2_debug ("Checking group descriptors");
555
556         for (i = 0; i < sbi->s_groups_count; i++)
557         {
558                 if (i == sbi->s_groups_count - 1)
559                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
560                 else
561                         last_block = first_block +
562                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
563
564                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
565                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
566                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
567                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
568                 {
569                         ext2_error (sb, "ext2_check_descriptors",
570                                     "Block bitmap for group %d"
571                                     " not in group (block %lu)!",
572                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
573                         return 0;
574                 }
575                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
576                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
577                 {
578                         ext2_error (sb, "ext2_check_descriptors",
579                                     "Inode bitmap for group %d"
580                                     " not in group (block %lu)!",
581                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
582                         return 0;
583                 }
584                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
585                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >
586                     last_block)
587                 {
588                         ext2_error (sb, "ext2_check_descriptors",
589                                     "Inode table for group %d"
590                                     " not in group (block %lu)!",
591                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
592                         return 0;
593                 }
594                 first_block += EXT2_BLOCKS_PER_GROUP(sb);
595                 gdp++;
596         }
597         return 1;
598 }
599
600 /*
601  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
602  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
603  * We need to be 1 filesystem block less than the 2^32 sector limit.
604  */
605 static loff_t ext2_max_size(int bits)
606 {
607         loff_t res = EXT2_NDIR_BLOCKS;
608         /* This constant is calculated to be the largest file size for a
609          * dense, 4k-blocksize file such that the total number of
610          * sectors in the file, including data and all indirect blocks,
611          * does not exceed 2^32. */
612         const loff_t upper_limit = 0x1ff7fffd000LL;
613
614         res += 1LL << (bits-2);
615         res += 1LL << (2*(bits-2));
616         res += 1LL << (3*(bits-2));
617         res <<= bits;
618         if (res > upper_limit)
619                 res = upper_limit;
620         return res;
621 }
622
623 static unsigned long descriptor_loc(struct super_block *sb,
624                                     unsigned long logic_sb_block,
625                                     int nr)
626 {
627         struct ext2_sb_info *sbi = EXT2_SB(sb);
628         unsigned long bg, first_data_block, first_meta_bg;
629         int has_super = 0;
630         
631         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
632         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
633
634         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
635             nr < first_meta_bg)
636                 return (logic_sb_block + nr + 1);
637         bg = sbi->s_desc_per_block * nr;
638         if (ext2_bg_has_super(sb, bg))
639                 has_super = 1;
640         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
641 }
642
643 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
644 {
645         struct buffer_head * bh;
646         struct ext2_sb_info * sbi;
647         struct ext2_super_block * es;
648         struct inode *root;
649         unsigned long block;
650         unsigned long sb_block = get_sb_block(&data);
651         unsigned long logic_sb_block;
652         unsigned long offset = 0;
653         unsigned long def_mount_opts;
654         int blocksize = BLOCK_SIZE;
655         int db_count;
656         int i, j;
657         __le32 features;
658
659         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
660         if (!sbi)
661                 return -ENOMEM;
662         sb->s_fs_info = sbi;
663
664         /*
665          * See what the current blocksize for the device is, and
666          * use that as the blocksize.  Otherwise (or if the blocksize
667          * is smaller than the default) use the default.
668          * This is important for devices that have a hardware
669          * sectorsize that is larger than the default.
670          */
671         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
672         if (!blocksize) {
673                 printk ("EXT2-fs: unable to set blocksize\n");
674                 goto failed_sbi;
675         }
676
677         /*
678          * If the superblock doesn't start on a hardware sector boundary,
679          * calculate the offset.  
680          */
681         if (blocksize != BLOCK_SIZE) {
682                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
683                 offset = (sb_block*BLOCK_SIZE) % blocksize;
684         } else {
685                 logic_sb_block = sb_block;
686         }
687
688         if (!(bh = sb_bread(sb, logic_sb_block))) {
689                 printk ("EXT2-fs: unable to read superblock\n");
690                 goto failed_sbi;
691         }
692         /*
693          * Note: s_es must be initialized as soon as possible because
694          *       some ext2 macro-instructions depend on its value
695          */
696         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
697         sbi->s_es = es;
698         sb->s_magic = le16_to_cpu(es->s_magic);
699
700         if (sb->s_magic != EXT2_SUPER_MAGIC)
701                 goto cantfind_ext2;
702
703         /* Set defaults before we parse the mount options */
704         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
705         if (def_mount_opts & EXT2_DEFM_DEBUG)
706                 set_opt(sbi->s_mount_opt, DEBUG);
707         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
708                 set_opt(sbi->s_mount_opt, GRPID);
709         if (def_mount_opts & EXT2_DEFM_UID16)
710                 set_opt(sbi->s_mount_opt, NO_UID32);
711 #ifdef CONFIG_EXT2_FS_XATTR
712         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
713                 set_opt(sbi->s_mount_opt, XATTR_USER);
714 #endif
715 #ifdef CONFIG_EXT2_FS_POSIX_ACL
716         if (def_mount_opts & EXT2_DEFM_ACL)
717                 set_opt(sbi->s_mount_opt, POSIX_ACL);
718 #endif
719         
720         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
721                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
722         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
723                 set_opt(sbi->s_mount_opt, ERRORS_RO);
724         else
725                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
726
727         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
728         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
729         
730         if (!parse_options ((char *) data, sbi))
731                 goto failed_mount;
732
733         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
734                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
735                  MS_POSIXACL : 0);
736
737         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
738                                     EXT2_MOUNT_XIP if not */
739
740         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
741             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
742              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
743              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
744                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
745                        "running e2fsck is recommended\n");
746         /*
747          * Check feature flags regardless of the revision level, since we
748          * previously didn't change the revision level when setting the flags,
749          * so there is a chance incompat flags are set on a rev 0 filesystem.
750          */
751         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
752         if (features) {
753                 printk("EXT2-fs: %s: couldn't mount because of "
754                        "unsupported optional features (%x).\n",
755                        sb->s_id, le32_to_cpu(features));
756                 goto failed_mount;
757         }
758         if (!(sb->s_flags & MS_RDONLY) &&
759             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
760                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
761                        "unsupported optional features (%x).\n",
762                        sb->s_id, le32_to_cpu(features));
763                 goto failed_mount;
764         }
765
766         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
767
768         if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
769                                   (sb->s_blocksize != blocksize))) {
770                 if (!silent)
771                         printk("XIP: Unsupported blocksize\n");
772                 goto failed_mount;
773         }
774
775         /* If the blocksize doesn't match, re-read the thing.. */
776         if (sb->s_blocksize != blocksize) {
777                 brelse(bh);
778
779                 if (!sb_set_blocksize(sb, blocksize)) {
780                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
781                         goto failed_sbi;
782                 }
783
784                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
785                 offset = (sb_block*BLOCK_SIZE) % blocksize;
786                 bh = sb_bread(sb, logic_sb_block);
787                 if(!bh) {
788                         printk("EXT2-fs: Couldn't read superblock on "
789                                "2nd try.\n");
790                         goto failed_sbi;
791                 }
792                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
793                 sbi->s_es = es;
794                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
795                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
796                         goto failed_mount;
797                 }
798         }
799
800         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
801
802         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
803                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
804                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
805         } else {
806                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
807                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
808                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
809                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
810                     (sbi->s_inode_size > blocksize)) {
811                         printk ("EXT2-fs: unsupported inode size: %d\n",
812                                 sbi->s_inode_size);
813                         goto failed_mount;
814                 }
815         }
816
817         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
818                                    le32_to_cpu(es->s_log_frag_size);
819         if (sbi->s_frag_size == 0)
820                 goto cantfind_ext2;
821         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
822
823         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
824         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
825         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
826
827         if (EXT2_INODE_SIZE(sb) == 0)
828                 goto cantfind_ext2;
829         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
830         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
831                 goto cantfind_ext2;
832         sbi->s_itb_per_group = sbi->s_inodes_per_group /
833                                         sbi->s_inodes_per_block;
834         sbi->s_desc_per_block = sb->s_blocksize /
835                                         sizeof (struct ext2_group_desc);
836         sbi->s_sbh = bh;
837         sbi->s_mount_state = le16_to_cpu(es->s_state);
838         sbi->s_addr_per_block_bits =
839                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
840         sbi->s_desc_per_block_bits =
841                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
842
843         if (sb->s_magic != EXT2_SUPER_MAGIC)
844                 goto cantfind_ext2;
845
846         if (sb->s_blocksize != bh->b_size) {
847                 if (!silent)
848                         printk ("VFS: Unsupported blocksize on dev "
849                                 "%s.\n", sb->s_id);
850                 goto failed_mount;
851         }
852
853         if (sb->s_blocksize != sbi->s_frag_size) {
854                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
855                         sbi->s_frag_size, sb->s_blocksize);
856                 goto failed_mount;
857         }
858
859         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
860                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
861                         sbi->s_blocks_per_group);
862                 goto failed_mount;
863         }
864         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
865                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
866                         sbi->s_frags_per_group);
867                 goto failed_mount;
868         }
869         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
870                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
871                         sbi->s_inodes_per_group);
872                 goto failed_mount;
873         }
874
875         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
876                 goto cantfind_ext2;
877         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
878                                 le32_to_cpu(es->s_first_data_block) - 1)
879                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
880         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
881                    EXT2_DESC_PER_BLOCK(sb);
882         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
883         if (sbi->s_group_desc == NULL) {
884                 printk ("EXT2-fs: not enough memory\n");
885                 goto failed_mount;
886         }
887         bgl_lock_init(&sbi->s_blockgroup_lock);
888         sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
889                                GFP_KERNEL);
890         if (!sbi->s_debts) {
891                 printk ("EXT2-fs: not enough memory\n");
892                 goto failed_mount_group_desc;
893         }
894         memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
895         for (i = 0; i < db_count; i++) {
896                 block = descriptor_loc(sb, logic_sb_block, i);
897                 sbi->s_group_desc[i] = sb_bread(sb, block);
898                 if (!sbi->s_group_desc[i]) {
899                         for (j = 0; j < i; j++)
900                                 brelse (sbi->s_group_desc[j]);
901                         printk ("EXT2-fs: unable to read group descriptors\n");
902                         goto failed_mount_group_desc;
903                 }
904         }
905         if (!ext2_check_descriptors (sb)) {
906                 printk ("EXT2-fs: group descriptors corrupted!\n");
907                 goto failed_mount2;
908         }
909         sbi->s_gdb_count = db_count;
910         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
911         spin_lock_init(&sbi->s_next_gen_lock);
912
913         percpu_counter_init(&sbi->s_freeblocks_counter,
914                                 ext2_count_free_blocks(sb));
915         percpu_counter_init(&sbi->s_freeinodes_counter,
916                                 ext2_count_free_inodes(sb));
917         percpu_counter_init(&sbi->s_dirs_counter,
918                                 ext2_count_dirs(sb));
919         /*
920          * set up enough so that it can read an inode
921          */
922         sb->s_op = &ext2_sops;
923         sb->s_export_op = &ext2_export_ops;
924         sb->s_xattr = ext2_xattr_handlers;
925         root = iget(sb, EXT2_ROOT_INO);
926         sb->s_root = d_alloc_root(root);
927         if (!sb->s_root) {
928                 iput(root);
929                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
930                 goto failed_mount3;
931         }
932         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
933                 dput(sb->s_root);
934                 sb->s_root = NULL;
935                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
936                 goto failed_mount3;
937         }
938         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
939                 ext2_warning(sb, __FUNCTION__,
940                         "mounting ext3 filesystem as ext2");
941         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
942         return 0;
943
944 cantfind_ext2:
945         if (!silent)
946                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
947                        sb->s_id);
948         goto failed_mount;
949 failed_mount3:
950         percpu_counter_destroy(&sbi->s_freeblocks_counter);
951         percpu_counter_destroy(&sbi->s_freeinodes_counter);
952         percpu_counter_destroy(&sbi->s_dirs_counter);
953 failed_mount2:
954         for (i = 0; i < db_count; i++)
955                 brelse(sbi->s_group_desc[i]);
956 failed_mount_group_desc:
957         kfree(sbi->s_group_desc);
958         kfree(sbi->s_debts);
959 failed_mount:
960         brelse(bh);
961 failed_sbi:
962         sb->s_fs_info = NULL;
963         kfree(sbi);
964         return -EINVAL;
965 }
966
967 static void ext2_commit_super (struct super_block * sb,
968                                struct ext2_super_block * es)
969 {
970         es->s_wtime = cpu_to_le32(get_seconds());
971         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
972         sb->s_dirt = 0;
973 }
974
975 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
976 {
977         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
978         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
979         es->s_wtime = cpu_to_le32(get_seconds());
980         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
981         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
982         sb->s_dirt = 0;
983 }
984
985 /*
986  * In the second extended file system, it is not necessary to
987  * write the super block since we use a mapping of the
988  * disk super block in a buffer.
989  *
990  * However, this function is still used to set the fs valid
991  * flags to 0.  We need to set this flag to 0 since the fs
992  * may have been checked while mounted and e2fsck may have
993  * set s_state to EXT2_VALID_FS after some corrections.
994  */
995
996 void ext2_write_super (struct super_block * sb)
997 {
998         struct ext2_super_block * es;
999         lock_kernel();
1000         if (!(sb->s_flags & MS_RDONLY)) {
1001                 es = EXT2_SB(sb)->s_es;
1002
1003                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
1004                         ext2_debug ("setting valid to 0\n");
1005                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
1006                                                   ~EXT2_VALID_FS);
1007                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1008                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1009                         es->s_mtime = cpu_to_le32(get_seconds());
1010                         ext2_sync_super(sb, es);
1011                 } else
1012                         ext2_commit_super (sb, es);
1013         }
1014         sb->s_dirt = 0;
1015         unlock_kernel();
1016 }
1017
1018 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1019 {
1020         struct ext2_sb_info * sbi = EXT2_SB(sb);
1021         struct ext2_super_block * es;
1022         unsigned long old_mount_opt = sbi->s_mount_opt;
1023         struct ext2_mount_options old_opts;
1024         unsigned long old_sb_flags;
1025         int err;
1026
1027         /* Store the old options */
1028         old_sb_flags = sb->s_flags;
1029         old_opts.s_mount_opt = sbi->s_mount_opt;
1030         old_opts.s_resuid = sbi->s_resuid;
1031         old_opts.s_resgid = sbi->s_resgid;
1032
1033         /*
1034          * Allow the "check" option to be passed as a remount option.
1035          */
1036         if (!parse_options (data, sbi)) {
1037                 err = -EINVAL;
1038                 goto restore_opts;
1039         }
1040
1041         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1042                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1043
1044         es = sbi->s_es;
1045         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1046             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1047             invalidate_inodes(sb))
1048                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1049                              "xip remain in cache (no functional problem)");
1050         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1051                 return 0;
1052         if (*flags & MS_RDONLY) {
1053                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1054                     !(sbi->s_mount_state & EXT2_VALID_FS))
1055                         return 0;
1056                 /*
1057                  * OK, we are remounting a valid rw partition rdonly, so set
1058                  * the rdonly flag and then mark the partition as valid again.
1059                  */
1060                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1061                 es->s_mtime = cpu_to_le32(get_seconds());
1062         } else {
1063                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1064                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1065                 if (ret) {
1066                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1067                                "unsupported optional features (%x).\n",
1068                                sb->s_id, le32_to_cpu(ret));
1069                         err = -EROFS;
1070                         goto restore_opts;
1071                 }
1072                 /*
1073                  * Mounting a RDONLY partition read-write, so reread and
1074                  * store the current valid flag.  (It may have been changed
1075                  * by e2fsck since we originally mounted the partition.)
1076                  */
1077                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1078                 if (!ext2_setup_super (sb, es, 0))
1079                         sb->s_flags &= ~MS_RDONLY;
1080         }
1081         ext2_sync_super(sb, es);
1082         return 0;
1083 restore_opts:
1084         sbi->s_mount_opt = old_opts.s_mount_opt;
1085         sbi->s_resuid = old_opts.s_resuid;
1086         sbi->s_resgid = old_opts.s_resgid;
1087         sb->s_flags = old_sb_flags;
1088         return err;
1089 }
1090
1091 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1092 {
1093         struct super_block *sb = dentry->d_sb;
1094         struct ext2_sb_info *sbi = EXT2_SB(sb);
1095         struct ext2_super_block *es = sbi->s_es;
1096         unsigned long overhead;
1097         int i;
1098         u64 fsid;
1099
1100         if (test_opt (sb, MINIX_DF))
1101                 overhead = 0;
1102         else {
1103                 /*
1104                  * Compute the overhead (FS structures)
1105                  */
1106
1107                 /*
1108                  * All of the blocks before first_data_block are
1109                  * overhead
1110                  */
1111                 overhead = le32_to_cpu(es->s_first_data_block);
1112
1113                 /*
1114                  * Add the overhead attributed to the superblock and
1115                  * block group descriptors.  If the sparse superblocks
1116                  * feature is turned on, then not all groups have this.
1117                  */
1118                 for (i = 0; i < sbi->s_groups_count; i++)
1119                         overhead += ext2_bg_has_super(sb, i) +
1120                                 ext2_bg_num_gdb(sb, i);
1121
1122                 /*
1123                  * Every block group has an inode bitmap, a block
1124                  * bitmap, and an inode table.
1125                  */
1126                 overhead += (sbi->s_groups_count *
1127                              (2 + sbi->s_itb_per_group));
1128         }
1129
1130         buf->f_type = EXT2_SUPER_MAGIC;
1131         buf->f_bsize = sb->s_blocksize;
1132         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - overhead;
1133         buf->f_bfree = ext2_count_free_blocks(sb);
1134         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1135         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1136                 buf->f_bavail = 0;
1137         buf->f_files = le32_to_cpu(es->s_inodes_count);
1138         buf->f_ffree = ext2_count_free_inodes(sb);
1139         buf->f_namelen = EXT2_NAME_LEN;
1140         fsid = le64_to_cpup((void *)es->s_uuid) ^
1141                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1142         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1143         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1144         return 0;
1145 }
1146
1147 static int ext2_get_sb(struct file_system_type *fs_type,
1148         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1149 {
1150         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1151 }
1152
1153 #ifdef CONFIG_QUOTA
1154
1155 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1156  * acquiring the locks... As quota files are never truncated and quota code
1157  * itself serializes the operations (and noone else should touch the files)
1158  * we don't have to be afraid of races */
1159 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1160                                size_t len, loff_t off)
1161 {
1162         struct inode *inode = sb_dqopt(sb)->files[type];
1163         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1164         int err = 0;
1165         int offset = off & (sb->s_blocksize - 1);
1166         int tocopy;
1167         size_t toread;
1168         struct buffer_head tmp_bh;
1169         struct buffer_head *bh;
1170         loff_t i_size = i_size_read(inode);
1171
1172         if (off > i_size)
1173                 return 0;
1174         if (off+len > i_size)
1175                 len = i_size-off;
1176         toread = len;
1177         while (toread > 0) {
1178                 tocopy = sb->s_blocksize - offset < toread ?
1179                                 sb->s_blocksize - offset : toread;
1180
1181                 tmp_bh.b_state = 0;
1182                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1183                 if (err)
1184                         return err;
1185                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1186                         memset(data, 0, tocopy);
1187                 else {
1188                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1189                         if (!bh)
1190                                 return -EIO;
1191                         memcpy(data, bh->b_data+offset, tocopy);
1192                         brelse(bh);
1193                 }
1194                 offset = 0;
1195                 toread -= tocopy;
1196                 data += tocopy;
1197                 blk++;
1198         }
1199         return len;
1200 }
1201
1202 /* Write to quotafile */
1203 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1204                                 const char *data, size_t len, loff_t off)
1205 {
1206         struct inode *inode = sb_dqopt(sb)->files[type];
1207         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1208         int err = 0;
1209         int offset = off & (sb->s_blocksize - 1);
1210         int tocopy;
1211         size_t towrite = len;
1212         struct buffer_head tmp_bh;
1213         struct buffer_head *bh;
1214
1215         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1216         while (towrite > 0) {
1217                 tocopy = sb->s_blocksize - offset < towrite ?
1218                                 sb->s_blocksize - offset : towrite;
1219
1220                 tmp_bh.b_state = 0;
1221                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1222                 if (err)
1223                         goto out;
1224                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1225                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1226                 else
1227                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1228                 if (!bh) {
1229                         err = -EIO;
1230                         goto out;
1231                 }
1232                 lock_buffer(bh);
1233                 memcpy(bh->b_data+offset, data, tocopy);
1234                 flush_dcache_page(bh->b_page);
1235                 set_buffer_uptodate(bh);
1236                 mark_buffer_dirty(bh);
1237                 unlock_buffer(bh);
1238                 brelse(bh);
1239                 offset = 0;
1240                 towrite -= tocopy;
1241                 data += tocopy;
1242                 blk++;
1243         }
1244 out:
1245         if (len == towrite)
1246                 return err;
1247         if (inode->i_size < off+len-towrite)
1248                 i_size_write(inode, off+len-towrite);
1249         inode->i_version++;
1250         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1251         mark_inode_dirty(inode);
1252         mutex_unlock(&inode->i_mutex);
1253         return len - towrite;
1254 }
1255
1256 #endif
1257
1258 static struct file_system_type ext2_fs_type = {
1259         .owner          = THIS_MODULE,
1260         .name           = "ext2",
1261         .get_sb         = ext2_get_sb,
1262         .kill_sb        = kill_block_super,
1263         .fs_flags       = FS_REQUIRES_DEV,
1264 };
1265
1266 static int __init init_ext2_fs(void)
1267 {
1268         int err = init_ext2_xattr();
1269         if (err)
1270                 return err;
1271         err = init_inodecache();
1272         if (err)
1273                 goto out1;
1274         err = register_filesystem(&ext2_fs_type);
1275         if (err)
1276                 goto out;
1277         return 0;
1278 out:
1279         destroy_inodecache();
1280 out1:
1281         exit_ext2_xattr();
1282         return err;
1283 }
1284
1285 static void __exit exit_ext2_fs(void)
1286 {
1287         unregister_filesystem(&ext2_fs_type);
1288         destroy_inodecache();
1289         exit_ext2_xattr();
1290 }
1291
1292 module_init(init_ext2_fs)
1293 module_exit(exit_ext2_fs)