5de5061eb331c811c9ed0c9baab5f75655c7ae99
[linux-2.6.git] / fs / ext2 / super.c
1 /*
2  *  linux/fs/ext2/super.c
3  *
4  * Copyright (C) 1992, 1993, 1994, 1995
5  * Remy Card (card@masi.ibp.fr)
6  * Laboratoire MASI - Institut Blaise Pascal
7  * Universite Pierre et Marie Curie (Paris VI)
8  *
9  *  from
10  *
11  *  linux/fs/minix/inode.c
12  *
13  *  Copyright (C) 1991, 1992  Linus Torvalds
14  *
15  *  Big-endian to little-endian byte-swapping/bitmaps by
16  *        David S. Miller (davem@caip.rutgers.edu), 1995
17  */
18
19 #include <linux/module.h>
20 #include <linux/string.h>
21 #include <linux/fs.h>
22 #include <linux/slab.h>
23 #include <linux/init.h>
24 #include <linux/blkdev.h>
25 #include <linux/parser.h>
26 #include <linux/random.h>
27 #include <linux/buffer_head.h>
28 #include <linux/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         rwlock_init(&ei->i_meta_lock);
164 #ifdef CONFIG_EXT2_FS_XATTR
165         init_rwsem(&ei->xattr_sem);
166 #endif
167         inode_init_once(&ei->vfs_inode);
168 }
169  
170 static int init_inodecache(void)
171 {
172         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
173                                              sizeof(struct ext2_inode_info),
174                                              0, (SLAB_RECLAIM_ACCOUNT|
175                                                 SLAB_MEM_SPREAD),
176                                              init_once, NULL);
177         if (ext2_inode_cachep == NULL)
178                 return -ENOMEM;
179         return 0;
180 }
181
182 static void destroy_inodecache(void)
183 {
184         kmem_cache_destroy(ext2_inode_cachep);
185 }
186
187 static void ext2_clear_inode(struct inode *inode)
188 {
189 #ifdef CONFIG_EXT2_FS_POSIX_ACL
190         struct ext2_inode_info *ei = EXT2_I(inode);
191
192         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
193                 posix_acl_release(ei->i_acl);
194                 ei->i_acl = EXT2_ACL_NOT_CACHED;
195         }
196         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
197                 posix_acl_release(ei->i_default_acl);
198                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
199         }
200 #endif
201 }
202
203 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
204 {
205         struct ext2_sb_info *sbi = EXT2_SB(vfs->mnt_sb);
206
207         if (sbi->s_mount_opt & EXT2_MOUNT_GRPID)
208                 seq_puts(seq, ",grpid");
209
210 #if defined(CONFIG_QUOTA)
211         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
212                 seq_puts(seq, ",usrquota");
213
214         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
215                 seq_puts(seq, ",grpquota");
216 #endif
217
218 #if defined(CONFIG_EXT2_FS_XIP)
219         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
220                 seq_puts(seq, ",xip");
221 #endif
222
223         return 0;
224 }
225
226 #ifdef CONFIG_QUOTA
227 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
228 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
229 #endif
230
231 static const struct super_operations ext2_sops = {
232         .alloc_inode    = ext2_alloc_inode,
233         .destroy_inode  = ext2_destroy_inode,
234         .read_inode     = ext2_read_inode,
235         .write_inode    = ext2_write_inode,
236         .put_inode      = ext2_put_inode,
237         .delete_inode   = ext2_delete_inode,
238         .put_super      = ext2_put_super,
239         .write_super    = ext2_write_super,
240         .statfs         = ext2_statfs,
241         .remount_fs     = ext2_remount,
242         .clear_inode    = ext2_clear_inode,
243         .show_options   = ext2_show_options,
244 #ifdef CONFIG_QUOTA
245         .quota_read     = ext2_quota_read,
246         .quota_write    = ext2_quota_write,
247 #endif
248 };
249
250 static struct dentry *ext2_get_dentry(struct super_block *sb, void *vobjp)
251 {
252         __u32 *objp = vobjp;
253         unsigned long ino = objp[0];
254         __u32 generation = objp[1];
255         struct inode *inode;
256         struct dentry *result;
257
258         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
259                 return ERR_PTR(-ESTALE);
260         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
261                 return ERR_PTR(-ESTALE);
262
263         /* iget isn't really right if the inode is currently unallocated!!
264          * ext2_read_inode currently does appropriate checks, but
265          * it might be "neater" to call ext2_get_inode first and check
266          * if the inode is valid.....
267          */
268         inode = iget(sb, ino);
269         if (inode == NULL)
270                 return ERR_PTR(-ENOMEM);
271         if (is_bad_inode(inode) ||
272             (generation && inode->i_generation != generation)) {
273                 /* we didn't find the right inode.. */
274                 iput(inode);
275                 return ERR_PTR(-ESTALE);
276         }
277         /* now to find a dentry.
278          * If possible, get a well-connected one
279          */
280         result = d_alloc_anon(inode);
281         if (!result) {
282                 iput(inode);
283                 return ERR_PTR(-ENOMEM);
284         }
285         return result;
286 }
287
288 /* Yes, most of these are left as NULL!!
289  * A NULL value implies the default, which works with ext2-like file
290  * systems, but can be improved upon.
291  * Currently only get_parent is required.
292  */
293 static struct export_operations ext2_export_ops = {
294         .get_parent = ext2_get_parent,
295         .get_dentry = ext2_get_dentry,
296 };
297
298 static unsigned long get_sb_block(void **data)
299 {
300         unsigned long   sb_block;
301         char            *options = (char *) *data;
302
303         if (!options || strncmp(options, "sb=", 3) != 0)
304                 return 1;       /* Default location */
305         options += 3;
306         sb_block = simple_strtoul(options, &options, 0);
307         if (*options && *options != ',') {
308                 printk("EXT2-fs: Invalid sb specification: %s\n",
309                        (char *) *data);
310                 return 1;
311         }
312         if (*options == ',')
313                 options++;
314         *data = (void *) options;
315         return sb_block;
316 }
317
318 enum {
319         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
320         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
321         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
322         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
323         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
324         Opt_usrquota, Opt_grpquota
325 };
326
327 static match_table_t tokens = {
328         {Opt_bsd_df, "bsddf"},
329         {Opt_minix_df, "minixdf"},
330         {Opt_grpid, "grpid"},
331         {Opt_grpid, "bsdgroups"},
332         {Opt_nogrpid, "nogrpid"},
333         {Opt_nogrpid, "sysvgroups"},
334         {Opt_resgid, "resgid=%u"},
335         {Opt_resuid, "resuid=%u"},
336         {Opt_sb, "sb=%u"},
337         {Opt_err_cont, "errors=continue"},
338         {Opt_err_panic, "errors=panic"},
339         {Opt_err_ro, "errors=remount-ro"},
340         {Opt_nouid32, "nouid32"},
341         {Opt_nocheck, "check=none"},
342         {Opt_nocheck, "nocheck"},
343         {Opt_debug, "debug"},
344         {Opt_oldalloc, "oldalloc"},
345         {Opt_orlov, "orlov"},
346         {Opt_nobh, "nobh"},
347         {Opt_user_xattr, "user_xattr"},
348         {Opt_nouser_xattr, "nouser_xattr"},
349         {Opt_acl, "acl"},
350         {Opt_noacl, "noacl"},
351         {Opt_xip, "xip"},
352         {Opt_grpquota, "grpquota"},
353         {Opt_ignore, "noquota"},
354         {Opt_quota, "quota"},
355         {Opt_usrquota, "usrquota"},
356         {Opt_err, NULL}
357 };
358
359 static int parse_options (char * options,
360                           struct ext2_sb_info *sbi)
361 {
362         char * p;
363         substring_t args[MAX_OPT_ARGS];
364         int option;
365
366         if (!options)
367                 return 1;
368
369         while ((p = strsep (&options, ",")) != NULL) {
370                 int token;
371                 if (!*p)
372                         continue;
373
374                 token = match_token(p, tokens, args);
375                 switch (token) {
376                 case Opt_bsd_df:
377                         clear_opt (sbi->s_mount_opt, MINIX_DF);
378                         break;
379                 case Opt_minix_df:
380                         set_opt (sbi->s_mount_opt, MINIX_DF);
381                         break;
382                 case Opt_grpid:
383                         set_opt (sbi->s_mount_opt, GRPID);
384                         break;
385                 case Opt_nogrpid:
386                         clear_opt (sbi->s_mount_opt, GRPID);
387                         break;
388                 case Opt_resuid:
389                         if (match_int(&args[0], &option))
390                                 return 0;
391                         sbi->s_resuid = option;
392                         break;
393                 case Opt_resgid:
394                         if (match_int(&args[0], &option))
395                                 return 0;
396                         sbi->s_resgid = option;
397                         break;
398                 case Opt_sb:
399                         /* handled by get_sb_block() instead of here */
400                         /* *sb_block = match_int(&args[0]); */
401                         break;
402                 case Opt_err_panic:
403                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
404                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
405                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
406                         break;
407                 case Opt_err_ro:
408                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
409                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
410                         set_opt (sbi->s_mount_opt, ERRORS_RO);
411                         break;
412                 case Opt_err_cont:
413                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
414                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
415                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
416                         break;
417                 case Opt_nouid32:
418                         set_opt (sbi->s_mount_opt, NO_UID32);
419                         break;
420                 case Opt_nocheck:
421                         clear_opt (sbi->s_mount_opt, CHECK);
422                         break;
423                 case Opt_debug:
424                         set_opt (sbi->s_mount_opt, DEBUG);
425                         break;
426                 case Opt_oldalloc:
427                         set_opt (sbi->s_mount_opt, OLDALLOC);
428                         break;
429                 case Opt_orlov:
430                         clear_opt (sbi->s_mount_opt, OLDALLOC);
431                         break;
432                 case Opt_nobh:
433                         set_opt (sbi->s_mount_opt, NOBH);
434                         break;
435 #ifdef CONFIG_EXT2_FS_XATTR
436                 case Opt_user_xattr:
437                         set_opt (sbi->s_mount_opt, XATTR_USER);
438                         break;
439                 case Opt_nouser_xattr:
440                         clear_opt (sbi->s_mount_opt, XATTR_USER);
441                         break;
442 #else
443                 case Opt_user_xattr:
444                 case Opt_nouser_xattr:
445                         printk("EXT2 (no)user_xattr options not supported\n");
446                         break;
447 #endif
448 #ifdef CONFIG_EXT2_FS_POSIX_ACL
449                 case Opt_acl:
450                         set_opt(sbi->s_mount_opt, POSIX_ACL);
451                         break;
452                 case Opt_noacl:
453                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
454                         break;
455 #else
456                 case Opt_acl:
457                 case Opt_noacl:
458                         printk("EXT2 (no)acl options not supported\n");
459                         break;
460 #endif
461                 case Opt_xip:
462 #ifdef CONFIG_EXT2_FS_XIP
463                         set_opt (sbi->s_mount_opt, XIP);
464 #else
465                         printk("EXT2 xip option not supported\n");
466 #endif
467                         break;
468
469 #if defined(CONFIG_QUOTA)
470                 case Opt_quota:
471                 case Opt_usrquota:
472                         set_opt(sbi->s_mount_opt, USRQUOTA);
473                         break;
474
475                 case Opt_grpquota:
476                         set_opt(sbi->s_mount_opt, GRPQUOTA);
477                         break;
478 #else
479                 case Opt_quota:
480                 case Opt_usrquota:
481                 case Opt_grpquota:
482                         printk(KERN_ERR
483                                 "EXT2-fs: quota operations not supported.\n");
484
485                         break;
486 #endif
487
488                 case Opt_ignore:
489                         break;
490                 default:
491                         return 0;
492                 }
493         }
494         return 1;
495 }
496
497 static int ext2_setup_super (struct super_block * sb,
498                               struct ext2_super_block * es,
499                               int read_only)
500 {
501         int res = 0;
502         struct ext2_sb_info *sbi = EXT2_SB(sb);
503
504         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
505                 printk ("EXT2-fs warning: revision level too high, "
506                         "forcing read-only mode\n");
507                 res = MS_RDONLY;
508         }
509         if (read_only)
510                 return res;
511         if (!(sbi->s_mount_state & EXT2_VALID_FS))
512                 printk ("EXT2-fs warning: mounting unchecked fs, "
513                         "running e2fsck is recommended\n");
514         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
515                 printk ("EXT2-fs warning: mounting fs with errors, "
516                         "running e2fsck is recommended\n");
517         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
518                  le16_to_cpu(es->s_mnt_count) >=
519                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
520                 printk ("EXT2-fs warning: maximal mount count reached, "
521                         "running e2fsck is recommended\n");
522         else if (le32_to_cpu(es->s_checkinterval) &&
523                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
524                 printk ("EXT2-fs warning: checktime reached, "
525                         "running e2fsck is recommended\n");
526         if (!le16_to_cpu(es->s_max_mnt_count))
527                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
528         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
529         ext2_write_super(sb);
530         if (test_opt (sb, DEBUG))
531                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
532                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
533                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
534                         sbi->s_frag_size,
535                         sbi->s_groups_count,
536                         EXT2_BLOCKS_PER_GROUP(sb),
537                         EXT2_INODES_PER_GROUP(sb),
538                         sbi->s_mount_opt);
539         return res;
540 }
541
542 static int ext2_check_descriptors (struct super_block * sb)
543 {
544         int i;
545         int desc_block = 0;
546         struct ext2_sb_info *sbi = EXT2_SB(sb);
547         unsigned long first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
548         unsigned long last_block;
549         struct ext2_group_desc * gdp = NULL;
550
551         ext2_debug ("Checking group descriptors");
552
553         for (i = 0; i < sbi->s_groups_count; i++)
554         {
555                 if (i == sbi->s_groups_count - 1)
556                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
557                 else
558                         last_block = first_block +
559                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
560
561                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
562                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
563                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
564                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
565                 {
566                         ext2_error (sb, "ext2_check_descriptors",
567                                     "Block bitmap for group %d"
568                                     " not in group (block %lu)!",
569                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
570                         return 0;
571                 }
572                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
573                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
574                 {
575                         ext2_error (sb, "ext2_check_descriptors",
576                                     "Inode bitmap for group %d"
577                                     " not in group (block %lu)!",
578                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
579                         return 0;
580                 }
581                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
582                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >
583                     last_block)
584                 {
585                         ext2_error (sb, "ext2_check_descriptors",
586                                     "Inode table for group %d"
587                                     " not in group (block %lu)!",
588                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
589                         return 0;
590                 }
591                 first_block += EXT2_BLOCKS_PER_GROUP(sb);
592                 gdp++;
593         }
594         return 1;
595 }
596
597 /*
598  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
599  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
600  * We need to be 1 filesystem block less than the 2^32 sector limit.
601  */
602 static loff_t ext2_max_size(int bits)
603 {
604         loff_t res = EXT2_NDIR_BLOCKS;
605         /* This constant is calculated to be the largest file size for a
606          * dense, 4k-blocksize file such that the total number of
607          * sectors in the file, including data and all indirect blocks,
608          * does not exceed 2^32. */
609         const loff_t upper_limit = 0x1ff7fffd000LL;
610
611         res += 1LL << (bits-2);
612         res += 1LL << (2*(bits-2));
613         res += 1LL << (3*(bits-2));
614         res <<= bits;
615         if (res > upper_limit)
616                 res = upper_limit;
617         return res;
618 }
619
620 static unsigned long descriptor_loc(struct super_block *sb,
621                                     unsigned long logic_sb_block,
622                                     int nr)
623 {
624         struct ext2_sb_info *sbi = EXT2_SB(sb);
625         unsigned long bg, first_data_block, first_meta_bg;
626         int has_super = 0;
627         
628         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
629         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
630
631         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
632             nr < first_meta_bg)
633                 return (logic_sb_block + nr + 1);
634         bg = sbi->s_desc_per_block * nr;
635         if (ext2_bg_has_super(sb, bg))
636                 has_super = 1;
637         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
638 }
639
640 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
641 {
642         struct buffer_head * bh;
643         struct ext2_sb_info * sbi;
644         struct ext2_super_block * es;
645         struct inode *root;
646         unsigned long block;
647         unsigned long sb_block = get_sb_block(&data);
648         unsigned long logic_sb_block;
649         unsigned long offset = 0;
650         unsigned long def_mount_opts;
651         int blocksize = BLOCK_SIZE;
652         int db_count;
653         int i, j;
654         __le32 features;
655
656         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
657         if (!sbi)
658                 return -ENOMEM;
659         sb->s_fs_info = sbi;
660
661         /*
662          * See what the current blocksize for the device is, and
663          * use that as the blocksize.  Otherwise (or if the blocksize
664          * is smaller than the default) use the default.
665          * This is important for devices that have a hardware
666          * sectorsize that is larger than the default.
667          */
668         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
669         if (!blocksize) {
670                 printk ("EXT2-fs: unable to set blocksize\n");
671                 goto failed_sbi;
672         }
673
674         /*
675          * If the superblock doesn't start on a hardware sector boundary,
676          * calculate the offset.  
677          */
678         if (blocksize != BLOCK_SIZE) {
679                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
680                 offset = (sb_block*BLOCK_SIZE) % blocksize;
681         } else {
682                 logic_sb_block = sb_block;
683         }
684
685         if (!(bh = sb_bread(sb, logic_sb_block))) {
686                 printk ("EXT2-fs: unable to read superblock\n");
687                 goto failed_sbi;
688         }
689         /*
690          * Note: s_es must be initialized as soon as possible because
691          *       some ext2 macro-instructions depend on its value
692          */
693         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
694         sbi->s_es = es;
695         sb->s_magic = le16_to_cpu(es->s_magic);
696
697         if (sb->s_magic != EXT2_SUPER_MAGIC)
698                 goto cantfind_ext2;
699
700         /* Set defaults before we parse the mount options */
701         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
702         if (def_mount_opts & EXT2_DEFM_DEBUG)
703                 set_opt(sbi->s_mount_opt, DEBUG);
704         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
705                 set_opt(sbi->s_mount_opt, GRPID);
706         if (def_mount_opts & EXT2_DEFM_UID16)
707                 set_opt(sbi->s_mount_opt, NO_UID32);
708 #ifdef CONFIG_EXT2_FS_XATTR
709         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
710                 set_opt(sbi->s_mount_opt, XATTR_USER);
711 #endif
712 #ifdef CONFIG_EXT2_FS_POSIX_ACL
713         if (def_mount_opts & EXT2_DEFM_ACL)
714                 set_opt(sbi->s_mount_opt, POSIX_ACL);
715 #endif
716         
717         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
718                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
719         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
720                 set_opt(sbi->s_mount_opt, ERRORS_RO);
721         else
722                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
723
724         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
725         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
726         
727         if (!parse_options ((char *) data, sbi))
728                 goto failed_mount;
729
730         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
731                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
732                  MS_POSIXACL : 0);
733
734         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
735                                     EXT2_MOUNT_XIP if not */
736
737         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
738             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
739              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
740              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
741                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
742                        "running e2fsck is recommended\n");
743         /*
744          * Check feature flags regardless of the revision level, since we
745          * previously didn't change the revision level when setting the flags,
746          * so there is a chance incompat flags are set on a rev 0 filesystem.
747          */
748         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
749         if (features) {
750                 printk("EXT2-fs: %s: couldn't mount because of "
751                        "unsupported optional features (%x).\n",
752                        sb->s_id, le32_to_cpu(features));
753                 goto failed_mount;
754         }
755         if (!(sb->s_flags & MS_RDONLY) &&
756             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
757                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
758                        "unsupported optional features (%x).\n",
759                        sb->s_id, le32_to_cpu(features));
760                 goto failed_mount;
761         }
762
763         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
764
765         if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
766                                   (sb->s_blocksize != blocksize))) {
767                 if (!silent)
768                         printk("XIP: Unsupported blocksize\n");
769                 goto failed_mount;
770         }
771
772         /* If the blocksize doesn't match, re-read the thing.. */
773         if (sb->s_blocksize != blocksize) {
774                 brelse(bh);
775
776                 if (!sb_set_blocksize(sb, blocksize)) {
777                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
778                         goto failed_sbi;
779                 }
780
781                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
782                 offset = (sb_block*BLOCK_SIZE) % blocksize;
783                 bh = sb_bread(sb, logic_sb_block);
784                 if(!bh) {
785                         printk("EXT2-fs: Couldn't read superblock on "
786                                "2nd try.\n");
787                         goto failed_sbi;
788                 }
789                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
790                 sbi->s_es = es;
791                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
792                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
793                         goto failed_mount;
794                 }
795         }
796
797         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
798
799         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
800                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
801                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
802         } else {
803                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
804                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
805                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
806                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
807                     (sbi->s_inode_size > blocksize)) {
808                         printk ("EXT2-fs: unsupported inode size: %d\n",
809                                 sbi->s_inode_size);
810                         goto failed_mount;
811                 }
812         }
813
814         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
815                                    le32_to_cpu(es->s_log_frag_size);
816         if (sbi->s_frag_size == 0)
817                 goto cantfind_ext2;
818         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
819
820         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
821         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
822         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
823
824         if (EXT2_INODE_SIZE(sb) == 0)
825                 goto cantfind_ext2;
826         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
827         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
828                 goto cantfind_ext2;
829         sbi->s_itb_per_group = sbi->s_inodes_per_group /
830                                         sbi->s_inodes_per_block;
831         sbi->s_desc_per_block = sb->s_blocksize /
832                                         sizeof (struct ext2_group_desc);
833         sbi->s_sbh = bh;
834         sbi->s_mount_state = le16_to_cpu(es->s_state);
835         sbi->s_addr_per_block_bits =
836                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
837         sbi->s_desc_per_block_bits =
838                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
839
840         if (sb->s_magic != EXT2_SUPER_MAGIC)
841                 goto cantfind_ext2;
842
843         if (sb->s_blocksize != bh->b_size) {
844                 if (!silent)
845                         printk ("VFS: Unsupported blocksize on dev "
846                                 "%s.\n", sb->s_id);
847                 goto failed_mount;
848         }
849
850         if (sb->s_blocksize != sbi->s_frag_size) {
851                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
852                         sbi->s_frag_size, sb->s_blocksize);
853                 goto failed_mount;
854         }
855
856         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
857                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
858                         sbi->s_blocks_per_group);
859                 goto failed_mount;
860         }
861         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
862                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
863                         sbi->s_frags_per_group);
864                 goto failed_mount;
865         }
866         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
867                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
868                         sbi->s_inodes_per_group);
869                 goto failed_mount;
870         }
871
872         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
873                 goto cantfind_ext2;
874         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
875                                 le32_to_cpu(es->s_first_data_block) - 1)
876                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
877         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
878                    EXT2_DESC_PER_BLOCK(sb);
879         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
880         if (sbi->s_group_desc == NULL) {
881                 printk ("EXT2-fs: not enough memory\n");
882                 goto failed_mount;
883         }
884         bgl_lock_init(&sbi->s_blockgroup_lock);
885         sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
886                                GFP_KERNEL);
887         if (!sbi->s_debts) {
888                 printk ("EXT2-fs: not enough memory\n");
889                 goto failed_mount_group_desc;
890         }
891         memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
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         percpu_counter_init(&sbi->s_freeblocks_counter,
911                                 ext2_count_free_blocks(sb));
912         percpu_counter_init(&sbi->s_freeinodes_counter,
913                                 ext2_count_free_inodes(sb));
914         percpu_counter_init(&sbi->s_dirs_counter,
915                                 ext2_count_dirs(sb));
916         /*
917          * set up enough so that it can read an inode
918          */
919         sb->s_op = &ext2_sops;
920         sb->s_export_op = &ext2_export_ops;
921         sb->s_xattr = ext2_xattr_handlers;
922         root = iget(sb, EXT2_ROOT_INO);
923         sb->s_root = d_alloc_root(root);
924         if (!sb->s_root) {
925                 iput(root);
926                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
927                 goto failed_mount3;
928         }
929         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
930                 dput(sb->s_root);
931                 sb->s_root = NULL;
932                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
933                 goto failed_mount3;
934         }
935         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
936                 ext2_warning(sb, __FUNCTION__,
937                         "mounting ext3 filesystem as ext2");
938         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
939         return 0;
940
941 cantfind_ext2:
942         if (!silent)
943                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
944                        sb->s_id);
945         goto failed_mount;
946 failed_mount3:
947         percpu_counter_destroy(&sbi->s_freeblocks_counter);
948         percpu_counter_destroy(&sbi->s_freeinodes_counter);
949         percpu_counter_destroy(&sbi->s_dirs_counter);
950 failed_mount2:
951         for (i = 0; i < db_count; i++)
952                 brelse(sbi->s_group_desc[i]);
953 failed_mount_group_desc:
954         kfree(sbi->s_group_desc);
955         kfree(sbi->s_debts);
956 failed_mount:
957         brelse(bh);
958 failed_sbi:
959         sb->s_fs_info = NULL;
960         kfree(sbi);
961         return -EINVAL;
962 }
963
964 static void ext2_commit_super (struct super_block * sb,
965                                struct ext2_super_block * es)
966 {
967         es->s_wtime = cpu_to_le32(get_seconds());
968         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
969         sb->s_dirt = 0;
970 }
971
972 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
973 {
974         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
975         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
976         es->s_wtime = cpu_to_le32(get_seconds());
977         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
978         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
979         sb->s_dirt = 0;
980 }
981
982 /*
983  * In the second extended file system, it is not necessary to
984  * write the super block since we use a mapping of the
985  * disk super block in a buffer.
986  *
987  * However, this function is still used to set the fs valid
988  * flags to 0.  We need to set this flag to 0 since the fs
989  * may have been checked while mounted and e2fsck may have
990  * set s_state to EXT2_VALID_FS after some corrections.
991  */
992
993 void ext2_write_super (struct super_block * sb)
994 {
995         struct ext2_super_block * es;
996         lock_kernel();
997         if (!(sb->s_flags & MS_RDONLY)) {
998                 es = EXT2_SB(sb)->s_es;
999
1000                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
1001                         ext2_debug ("setting valid to 0\n");
1002                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
1003                                                   ~EXT2_VALID_FS);
1004                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1005                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1006                         es->s_mtime = cpu_to_le32(get_seconds());
1007                         ext2_sync_super(sb, es);
1008                 } else
1009                         ext2_commit_super (sb, es);
1010         }
1011         sb->s_dirt = 0;
1012         unlock_kernel();
1013 }
1014
1015 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1016 {
1017         struct ext2_sb_info * sbi = EXT2_SB(sb);
1018         struct ext2_super_block * es;
1019         unsigned long old_mount_opt = sbi->s_mount_opt;
1020         struct ext2_mount_options old_opts;
1021         unsigned long old_sb_flags;
1022         int err;
1023
1024         /* Store the old options */
1025         old_sb_flags = sb->s_flags;
1026         old_opts.s_mount_opt = sbi->s_mount_opt;
1027         old_opts.s_resuid = sbi->s_resuid;
1028         old_opts.s_resgid = sbi->s_resgid;
1029
1030         /*
1031          * Allow the "check" option to be passed as a remount option.
1032          */
1033         if (!parse_options (data, sbi)) {
1034                 err = -EINVAL;
1035                 goto restore_opts;
1036         }
1037
1038         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1039                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1040
1041         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1042                                     EXT2_MOUNT_XIP if not */
1043
1044         if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1045                 printk("XIP: Unsupported blocksize\n");
1046                 err = -EINVAL;
1047                 goto restore_opts;
1048         }
1049
1050         es = sbi->s_es;
1051         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1052             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1053             invalidate_inodes(sb))
1054                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1055                              "xip remain in cache (no functional problem)");
1056         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1057                 return 0;
1058         if (*flags & MS_RDONLY) {
1059                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1060                     !(sbi->s_mount_state & EXT2_VALID_FS))
1061                         return 0;
1062                 /*
1063                  * OK, we are remounting a valid rw partition rdonly, so set
1064                  * the rdonly flag and then mark the partition as valid again.
1065                  */
1066                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1067                 es->s_mtime = cpu_to_le32(get_seconds());
1068         } else {
1069                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1070                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1071                 if (ret) {
1072                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1073                                "unsupported optional features (%x).\n",
1074                                sb->s_id, le32_to_cpu(ret));
1075                         err = -EROFS;
1076                         goto restore_opts;
1077                 }
1078                 /*
1079                  * Mounting a RDONLY partition read-write, so reread and
1080                  * store the current valid flag.  (It may have been changed
1081                  * by e2fsck since we originally mounted the partition.)
1082                  */
1083                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1084                 if (!ext2_setup_super (sb, es, 0))
1085                         sb->s_flags &= ~MS_RDONLY;
1086         }
1087         ext2_sync_super(sb, es);
1088         return 0;
1089 restore_opts:
1090         sbi->s_mount_opt = old_opts.s_mount_opt;
1091         sbi->s_resuid = old_opts.s_resuid;
1092         sbi->s_resgid = old_opts.s_resgid;
1093         sb->s_flags = old_sb_flags;
1094         return err;
1095 }
1096
1097 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1098 {
1099         struct super_block *sb = dentry->d_sb;
1100         struct ext2_sb_info *sbi = EXT2_SB(sb);
1101         struct ext2_super_block *es = sbi->s_es;
1102         unsigned long overhead;
1103         int i;
1104         u64 fsid;
1105
1106         if (test_opt (sb, MINIX_DF))
1107                 overhead = 0;
1108         else {
1109                 /*
1110                  * Compute the overhead (FS structures)
1111                  */
1112
1113                 /*
1114                  * All of the blocks before first_data_block are
1115                  * overhead
1116                  */
1117                 overhead = le32_to_cpu(es->s_first_data_block);
1118
1119                 /*
1120                  * Add the overhead attributed to the superblock and
1121                  * block group descriptors.  If the sparse superblocks
1122                  * feature is turned on, then not all groups have this.
1123                  */
1124                 for (i = 0; i < sbi->s_groups_count; i++)
1125                         overhead += ext2_bg_has_super(sb, i) +
1126                                 ext2_bg_num_gdb(sb, i);
1127
1128                 /*
1129                  * Every block group has an inode bitmap, a block
1130                  * bitmap, and an inode table.
1131                  */
1132                 overhead += (sbi->s_groups_count *
1133                              (2 + sbi->s_itb_per_group));
1134         }
1135
1136         buf->f_type = EXT2_SUPER_MAGIC;
1137         buf->f_bsize = sb->s_blocksize;
1138         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - overhead;
1139         buf->f_bfree = ext2_count_free_blocks(sb);
1140         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1141         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1142                 buf->f_bavail = 0;
1143         buf->f_files = le32_to_cpu(es->s_inodes_count);
1144         buf->f_ffree = ext2_count_free_inodes(sb);
1145         buf->f_namelen = EXT2_NAME_LEN;
1146         fsid = le64_to_cpup((void *)es->s_uuid) ^
1147                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1148         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1149         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1150         return 0;
1151 }
1152
1153 static int ext2_get_sb(struct file_system_type *fs_type,
1154         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1155 {
1156         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1157 }
1158
1159 #ifdef CONFIG_QUOTA
1160
1161 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1162  * acquiring the locks... As quota files are never truncated and quota code
1163  * itself serializes the operations (and noone else should touch the files)
1164  * we don't have to be afraid of races */
1165 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1166                                size_t len, loff_t off)
1167 {
1168         struct inode *inode = sb_dqopt(sb)->files[type];
1169         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1170         int err = 0;
1171         int offset = off & (sb->s_blocksize - 1);
1172         int tocopy;
1173         size_t toread;
1174         struct buffer_head tmp_bh;
1175         struct buffer_head *bh;
1176         loff_t i_size = i_size_read(inode);
1177
1178         if (off > i_size)
1179                 return 0;
1180         if (off+len > i_size)
1181                 len = i_size-off;
1182         toread = len;
1183         while (toread > 0) {
1184                 tocopy = sb->s_blocksize - offset < toread ?
1185                                 sb->s_blocksize - offset : toread;
1186
1187                 tmp_bh.b_state = 0;
1188                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1189                 if (err)
1190                         return err;
1191                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1192                         memset(data, 0, tocopy);
1193                 else {
1194                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1195                         if (!bh)
1196                                 return -EIO;
1197                         memcpy(data, bh->b_data+offset, tocopy);
1198                         brelse(bh);
1199                 }
1200                 offset = 0;
1201                 toread -= tocopy;
1202                 data += tocopy;
1203                 blk++;
1204         }
1205         return len;
1206 }
1207
1208 /* Write to quotafile */
1209 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1210                                 const char *data, size_t len, loff_t off)
1211 {
1212         struct inode *inode = sb_dqopt(sb)->files[type];
1213         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1214         int err = 0;
1215         int offset = off & (sb->s_blocksize - 1);
1216         int tocopy;
1217         size_t towrite = len;
1218         struct buffer_head tmp_bh;
1219         struct buffer_head *bh;
1220
1221         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1222         while (towrite > 0) {
1223                 tocopy = sb->s_blocksize - offset < towrite ?
1224                                 sb->s_blocksize - offset : towrite;
1225
1226                 tmp_bh.b_state = 0;
1227                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1228                 if (err)
1229                         goto out;
1230                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1231                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1232                 else
1233                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1234                 if (!bh) {
1235                         err = -EIO;
1236                         goto out;
1237                 }
1238                 lock_buffer(bh);
1239                 memcpy(bh->b_data+offset, data, tocopy);
1240                 flush_dcache_page(bh->b_page);
1241                 set_buffer_uptodate(bh);
1242                 mark_buffer_dirty(bh);
1243                 unlock_buffer(bh);
1244                 brelse(bh);
1245                 offset = 0;
1246                 towrite -= tocopy;
1247                 data += tocopy;
1248                 blk++;
1249         }
1250 out:
1251         if (len == towrite)
1252                 return err;
1253         if (inode->i_size < off+len-towrite)
1254                 i_size_write(inode, off+len-towrite);
1255         inode->i_version++;
1256         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1257         mark_inode_dirty(inode);
1258         mutex_unlock(&inode->i_mutex);
1259         return len - towrite;
1260 }
1261
1262 #endif
1263
1264 static struct file_system_type ext2_fs_type = {
1265         .owner          = THIS_MODULE,
1266         .name           = "ext2",
1267         .get_sb         = ext2_get_sb,
1268         .kill_sb        = kill_block_super,
1269         .fs_flags       = FS_REQUIRES_DEV,
1270 };
1271
1272 static int __init init_ext2_fs(void)
1273 {
1274         int err = init_ext2_xattr();
1275         if (err)
1276                 return err;
1277         err = init_inodecache();
1278         if (err)
1279                 goto out1;
1280         err = register_filesystem(&ext2_fs_type);
1281         if (err)
1282                 goto out;
1283         return 0;
1284 out:
1285         destroy_inodecache();
1286 out1:
1287         exit_ext2_xattr();
1288         return err;
1289 }
1290
1291 static void __exit exit_ext2_fs(void)
1292 {
1293         unregister_filesystem(&ext2_fs_type);
1294         destroy_inodecache();
1295         exit_ext2_xattr();
1296 }
1297
1298 module_init(init_ext2_fs)
1299 module_exit(exit_ext2_fs)