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xenbus_xs.c: fix a use-after-free
[net-next-2.6.git] / fs / ext2 / super.c
CommitLineData
1da177e4
LT		 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
1da177e4
LT		 19#include <linux/module.h>
20#include <linux/string.h>
8fc2751b 21#include <linux/fs.h>
1da177e4
LT		 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>
a5694255 28#include <linux/exportfs.h>
1da177e4
LT		 29#include <linux/smp_lock.h>
30#include <linux/vfs.h>
8fc2751b
MB		 31#include <linux/seq_file.h>
32#include <linux/mount.h>
1da177e4
LT		 33#include <asm/uaccess.h>
34#include "ext2.h"
35#include "xattr.h"
36#include "acl.h"
6d79125b 37#include "xip.h"
1da177e4
LT		 38
39static void ext2_sync_super(struct super_block *sb,
40 struct ext2_super_block *es);
41static int ext2_remount (struct super_block * sb, int * flags, char * data);
726c3342 42static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
1da177e4
LT		 43
44void ext2_error (struct super_block * sb, const char * function,
45 const char * fmt, ...)
46{
47 va_list args;
48 struct ext2_sb_info *sbi = EXT2_SB(sb);
49 struct ext2_super_block *es = sbi->s_es;
50
51 if (!(sb->s_flags & MS_RDONLY)) {
52 sbi->s_mount_state |= EXT2_ERROR_FS;
53 es->s_state =
54 cpu_to_le16(le16_to_cpu(es->s_state) | EXT2_ERROR_FS);
55 ext2_sync_super(sb, es);
56 }
57
58 va_start(args, fmt);
59 printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
60 vprintk(fmt, args);
61 printk("\n");
62 va_end(args);
63
64 if (test_opt(sb, ERRORS_PANIC))
65 panic("EXT2-fs panic from previous error\n");
66 if (test_opt(sb, ERRORS_RO)) {
67 printk("Remounting filesystem read-only\n");
68 sb->s_flags |= MS_RDONLY;
69 }
70}
71
72void ext2_warning (struct super_block * sb, const char * function,
73 const char * fmt, ...)
74{
75 va_list args;
76
77 va_start(args, fmt);
78 printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
79 sb->s_id, function);
80 vprintk(fmt, args);
81 printk("\n");
82 va_end(args);
83}
84
85void ext2_update_dynamic_rev(struct super_block *sb)
86{
87 struct ext2_super_block *es = EXT2_SB(sb)->s_es;
88
89 if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
90 return;
91
92 ext2_warning(sb, __FUNCTION__,
93 "updating to rev %d because of new feature flag, "
94 "running e2fsck is recommended",
95 EXT2_DYNAMIC_REV);
96
97 es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
98 es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
99 es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
100 /* leave es->s_feature_*compat flags alone */
101 /* es->s_uuid will be set by e2fsck if empty */
102
103 /*
104 * The rest of the superblock fields should be zero, and if not it
105 * means they are likely already in use, so leave them alone. We
106 * can leave it up to e2fsck to clean up any inconsistencies there.
107 */
108}
109
110static void ext2_put_super (struct super_block * sb)
111{
112 int db_count;
113 int i;
114 struct ext2_sb_info *sbi = EXT2_SB(sb);
115
116 ext2_xattr_put_super(sb);
117 if (!(sb->s_flags & MS_RDONLY)) {
118 struct ext2_super_block *es = sbi->s_es;
119
120 es->s_state = cpu_to_le16(sbi->s_mount_state);
121 ext2_sync_super(sb, es);
122 }
123 db_count = sbi->s_gdb_count;
124 for (i = 0; i < db_count; i++)
125 if (sbi->s_group_desc[i])
126 brelse (sbi->s_group_desc[i]);
127 kfree(sbi->s_group_desc);
128 kfree(sbi->s_debts);
129 percpu_counter_destroy(&sbi->s_freeblocks_counter);
130 percpu_counter_destroy(&sbi->s_freeinodes_counter);
131 percpu_counter_destroy(&sbi->s_dirs_counter);
132 brelse (sbi->s_sbh);
133 sb->s_fs_info = NULL;
134 kfree(sbi);
135
136 return;
137}
138
e18b890b 139static struct kmem_cache * ext2_inode_cachep;
1da177e4
LT		 140
141static struct inode *ext2_alloc_inode(struct super_block *sb)
142{
143 struct ext2_inode_info *ei;
e94b1766 144 ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
1da177e4
LT		 145 if (!ei)
146 return NULL;
147#ifdef CONFIG_EXT2_FS_POSIX_ACL
148 ei->i_acl = EXT2_ACL_NOT_CACHED;
149 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
150#endif
151 ei->vfs_inode.i_version = 1;
152 return &ei->vfs_inode;
153}
154
155static void ext2_destroy_inode(struct inode *inode)
156{
157 kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
158}
159
e18b890b 160static void init_once(void * foo, struct kmem_cache * cachep, unsigned long flags)
1da177e4
LT		 161{
162 struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
163
a35afb83 164 rwlock_init(&ei->i_meta_lock);
1da177e4 165#ifdef CONFIG_EXT2_FS_XATTR
a35afb83 166 init_rwsem(&ei->xattr_sem);
1da177e4 167#endif
a35afb83 168 inode_init_once(&ei->vfs_inode);
1da177e4 169}
20c2df83 170
1da177e4
LT		 171static int init_inodecache(void)
172{
173 ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
174 sizeof(struct ext2_inode_info),
fffb60f9
PJ		 175 0, (SLAB_RECLAIM_ACCOUNT|
176 SLAB_MEM_SPREAD),
20c2df83 177 init_once);
1da177e4
LT		 178 if (ext2_inode_cachep == NULL)
179 return -ENOMEM;
180 return 0;
181}
182
183static void destroy_inodecache(void)
184{
1a1d92c1 185 kmem_cache_destroy(ext2_inode_cachep);
1da177e4
LT		 186}
187
188static void ext2_clear_inode(struct inode *inode)
189{
190#ifdef CONFIG_EXT2_FS_POSIX_ACL
191 struct ext2_inode_info *ei = EXT2_I(inode);
192
193 if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
194 posix_acl_release(ei->i_acl);
195 ei->i_acl = EXT2_ACL_NOT_CACHED;
196 }
197 if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
198 posix_acl_release(ei->i_default_acl);
199 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
200 }
201#endif
1da177e4
LT		 202}
203
8fc2751b
MB		 204static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
205{
206 struct ext2_sb_info *sbi = EXT2_SB(vfs->mnt_sb);
207
208 if (sbi->s_mount_opt & EXT2_MOUNT_GRPID)
209 seq_puts(seq, ",grpid");
8fc2751b
MB		 210
211#if defined(CONFIG_QUOTA)
212 if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
213 seq_puts(seq, ",usrquota");
214
215 if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
216 seq_puts(seq, ",grpquota");
217#endif
218
83541796
CO		 219#if defined(CONFIG_EXT2_FS_XIP)
220 if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
221 seq_puts(seq, ",xip");
222#endif
223
8fc2751b
MB		 224 return 0;
225}
226
1da177e4
LT		 227#ifdef CONFIG_QUOTA
228static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
229static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
230#endif
231
ee9b6d61 232static const struct super_operations ext2_sops = {
1da177e4
LT		 233 .alloc_inode = ext2_alloc_inode,
234 .destroy_inode = ext2_destroy_inode,
235 .read_inode = ext2_read_inode,
236 .write_inode = ext2_write_inode,
e072c6f2 237 .put_inode = ext2_put_inode,
1da177e4
LT		 238 .delete_inode = ext2_delete_inode,
239 .put_super = ext2_put_super,
240 .write_super = ext2_write_super,
241 .statfs = ext2_statfs,
242 .remount_fs = ext2_remount,
243 .clear_inode = ext2_clear_inode,
8fc2751b 244 .show_options = ext2_show_options,
1da177e4
LT		 245#ifdef CONFIG_QUOTA
246 .quota_read = ext2_quota_read,
247 .quota_write = ext2_quota_write,
248#endif
249};
250
ecaff756
N		 251static struct dentry *ext2_get_dentry(struct super_block *sb, void *vobjp)
252{
253 __u32 *objp = vobjp;
254 unsigned long ino = objp[0];
255 __u32 generation = objp[1];
256 struct inode *inode;
257 struct dentry *result;
258
259 if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
260 return ERR_PTR(-ESTALE);
261 if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
262 return ERR_PTR(-ESTALE);
263
264 /* iget isn't really right if the inode is currently unallocated!!
265 * ext2_read_inode currently does appropriate checks, but
266 * it might be "neater" to call ext2_get_inode first and check
267 * if the inode is valid.....
268 */
269 inode = iget(sb, ino);
270 if (inode == NULL)
271 return ERR_PTR(-ENOMEM);
272 if (is_bad_inode(inode) ||
273 (generation && inode->i_generation != generation)) {
274 /* we didn't find the right inode.. */
275 iput(inode);
276 return ERR_PTR(-ESTALE);
277 }
278 /* now to find a dentry.
279 * If possible, get a well-connected one
280 */
281 result = d_alloc_anon(inode);
282 if (!result) {
283 iput(inode);
284 return ERR_PTR(-ENOMEM);
285 }
286 return result;
287}
288
1da177e4
LT		 289/* Yes, most of these are left as NULL!!
290 * A NULL value implies the default, which works with ext2-like file
291 * systems, but can be improved upon.
292 * Currently only get_parent is required.
293 */
1da177e4
LT		 294static struct export_operations ext2_export_ops = {
295 .get_parent = ext2_get_parent,
ecaff756 296 .get_dentry = ext2_get_dentry,
1da177e4
LT		 297};
298
299static unsigned long get_sb_block(void **data)
300{
301 unsigned long sb_block;
302 char *options = (char *) *data;
303
304 if (!options || strncmp(options, "sb=", 3) != 0)
305 return 1; /* Default location */
306 options += 3;
307 sb_block = simple_strtoul(options, &options, 0);
308 if (*options && *options != ',') {
309 printk("EXT2-fs: Invalid sb specification: %s\n",
310 (char *) *data);
311 return 1;
312 }
313 if (*options == ',')
314 options++;
315 *data = (void *) options;
316 return sb_block;
317}
318
319enum {
320 Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
8fc2751b 321 Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
2860b733 322 Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
8fc2751b
MB		 323 Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
324 Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
325 Opt_usrquota, Opt_grpquota
1da177e4
LT		 326};
327
328static match_table_t tokens = {
329 {Opt_bsd_df, "bsddf"},
330 {Opt_minix_df, "minixdf"},
331 {Opt_grpid, "grpid"},
332 {Opt_grpid, "bsdgroups"},
333 {Opt_nogrpid, "nogrpid"},
334 {Opt_nogrpid, "sysvgroups"},
335 {Opt_resgid, "resgid=%u"},
336 {Opt_resuid, "resuid=%u"},
337 {Opt_sb, "sb=%u"},
338 {Opt_err_cont, "errors=continue"},
339 {Opt_err_panic, "errors=panic"},
340 {Opt_err_ro, "errors=remount-ro"},
341 {Opt_nouid32, "nouid32"},
342 {Opt_nocheck, "check=none"},
343 {Opt_nocheck, "nocheck"},
1da177e4
LT		 344 {Opt_debug, "debug"},
345 {Opt_oldalloc, "oldalloc"},
346 {Opt_orlov, "orlov"},
347 {Opt_nobh, "nobh"},
348 {Opt_user_xattr, "user_xattr"},
349 {Opt_nouser_xattr, "nouser_xattr"},
350 {Opt_acl, "acl"},
351 {Opt_noacl, "noacl"},
6d79125b 352 {Opt_xip, "xip"},
8fc2751b 353 {Opt_grpquota, "grpquota"},
1da177e4 354 {Opt_ignore, "noquota"},
8fc2751b
MB		 355 {Opt_quota, "quota"},
356 {Opt_usrquota, "usrquota"},
1da177e4
LT		 357 {Opt_err, NULL}
358};
359
360static int parse_options (char * options,
361 struct ext2_sb_info *sbi)
362{
363 char * p;
364 substring_t args[MAX_OPT_ARGS];
1da177e4
LT		 365 int option;
366
367 if (!options)
368 return 1;
369
370 while ((p = strsep (&options, ",")) != NULL) {
371 int token;
372 if (!*p)
373 continue;
374
375 token = match_token(p, tokens, args);
376 switch (token) {
377 case Opt_bsd_df:
378 clear_opt (sbi->s_mount_opt, MINIX_DF);
379 break;
380 case Opt_minix_df:
381 set_opt (sbi->s_mount_opt, MINIX_DF);
382 break;
383 case Opt_grpid:
384 set_opt (sbi->s_mount_opt, GRPID);
385 break;
386 case Opt_nogrpid:
387 clear_opt (sbi->s_mount_opt, GRPID);
388 break;
389 case Opt_resuid:
390 if (match_int(&args[0], &option))
391 return 0;
392 sbi->s_resuid = option;
393 break;
394 case Opt_resgid:
395 if (match_int(&args[0], &option))
396 return 0;
397 sbi->s_resgid = option;
398 break;
399 case Opt_sb:
400 /* handled by get_sb_block() instead of here */
401 /* *sb_block = match_int(&args[0]); */
402 break;
403 case Opt_err_panic:
5a2b4062
VA		 404 clear_opt (sbi->s_mount_opt, ERRORS_CONT);
405 clear_opt (sbi->s_mount_opt, ERRORS_RO);
406 set_opt (sbi->s_mount_opt, ERRORS_PANIC);
1da177e4
LT		 407 break;
408 case Opt_err_ro:
5a2b4062
VA		 409 clear_opt (sbi->s_mount_opt, ERRORS_CONT);
410 clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
411 set_opt (sbi->s_mount_opt, ERRORS_RO);
1da177e4
LT		 412 break;
413 case Opt_err_cont:
5a2b4062
VA		 414 clear_opt (sbi->s_mount_opt, ERRORS_RO);
415 clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
416 set_opt (sbi->s_mount_opt, ERRORS_CONT);
1da177e4
LT		 417 break;
418 case Opt_nouid32:
419 set_opt (sbi->s_mount_opt, NO_UID32);
420 break;
1da177e4
LT		 421 case Opt_nocheck:
422 clear_opt (sbi->s_mount_opt, CHECK);
423 break;
424 case Opt_debug:
425 set_opt (sbi->s_mount_opt, DEBUG);
426 break;
427 case Opt_oldalloc:
428 set_opt (sbi->s_mount_opt, OLDALLOC);
429 break;
430 case Opt_orlov:
431 clear_opt (sbi->s_mount_opt, OLDALLOC);
432 break;
433 case Opt_nobh:
434 set_opt (sbi->s_mount_opt, NOBH);
435 break;
436#ifdef CONFIG_EXT2_FS_XATTR
437 case Opt_user_xattr:
438 set_opt (sbi->s_mount_opt, XATTR_USER);
439 break;
440 case Opt_nouser_xattr:
441 clear_opt (sbi->s_mount_opt, XATTR_USER);
442 break;
443#else
444 case Opt_user_xattr:
445 case Opt_nouser_xattr:
446 printk("EXT2 (no)user_xattr options not supported\n");
447 break;
448#endif
449#ifdef CONFIG_EXT2_FS_POSIX_ACL
450 case Opt_acl:
451 set_opt(sbi->s_mount_opt, POSIX_ACL);
452 break;
453 case Opt_noacl:
454 clear_opt(sbi->s_mount_opt, POSIX_ACL);
455 break;
456#else
457 case Opt_acl:
458 case Opt_noacl:
459 printk("EXT2 (no)acl options not supported\n");
460 break;
461#endif
6d79125b
CO		 462 case Opt_xip:
463#ifdef CONFIG_EXT2_FS_XIP
464 set_opt (sbi->s_mount_opt, XIP);
465#else
466 printk("EXT2 xip option not supported\n");
467#endif
468 break;
8fc2751b
MB		 469
470#if defined(CONFIG_QUOTA)
471 case Opt_quota:
472 case Opt_usrquota:
473 set_opt(sbi->s_mount_opt, USRQUOTA);
474 break;
475
476 case Opt_grpquota:
477 set_opt(sbi->s_mount_opt, GRPQUOTA);
478 break;
479#else
480 case Opt_quota:
481 case Opt_usrquota:
482 case Opt_grpquota:
483 printk(KERN_ERR
484 "EXT2-fs: quota operations not supported.\n");
485
486 break;
487#endif
488
1da177e4
LT		 489 case Opt_ignore:
490 break;
491 default:
492 return 0;
493 }
494 }
1da177e4
LT		 495 return 1;
496}
497
498static int ext2_setup_super (struct super_block * sb,
499 struct ext2_super_block * es,
500 int read_only)
501{
502 int res = 0;
503 struct ext2_sb_info *sbi = EXT2_SB(sb);
504
505 if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
506 printk ("EXT2-fs warning: revision level too high, "
507 "forcing read-only mode\n");
508 res = MS_RDONLY;
509 }
510 if (read_only)
511 return res;
512 if (!(sbi->s_mount_state & EXT2_VALID_FS))
513 printk ("EXT2-fs warning: mounting unchecked fs, "
514 "running e2fsck is recommended\n");
515 else if ((sbi->s_mount_state & EXT2_ERROR_FS))
516 printk ("EXT2-fs warning: mounting fs with errors, "
517 "running e2fsck is recommended\n");
518 else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
519 le16_to_cpu(es->s_mnt_count) >=
520 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
521 printk ("EXT2-fs warning: maximal mount count reached, "
522 "running e2fsck is recommended\n");
523 else if (le32_to_cpu(es->s_checkinterval) &&
524 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
525 printk ("EXT2-fs warning: checktime reached, "
526 "running e2fsck is recommended\n");
527 if (!le16_to_cpu(es->s_max_mnt_count))
528 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
529 es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
530 ext2_write_super(sb);
531 if (test_opt (sb, DEBUG))
532 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
533 "bpg=%lu, ipg=%lu, mo=%04lx]\n",
534 EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
535 sbi->s_frag_size,
536 sbi->s_groups_count,
537 EXT2_BLOCKS_PER_GROUP(sb),
538 EXT2_INODES_PER_GROUP(sb),
539 sbi->s_mount_opt);
1da177e4
LT		 540 return res;
541}
542
543static int ext2_check_descriptors (struct super_block * sb)
544{
545 int i;
546 int desc_block = 0;
547 struct ext2_sb_info *sbi = EXT2_SB(sb);
41f04d85
ES		 548 unsigned long first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
549 unsigned long last_block;
1da177e4
LT		 550 struct ext2_group_desc * gdp = NULL;
551
552 ext2_debug ("Checking group descriptors");
553
554 for (i = 0; i < sbi->s_groups_count; i++)
555 {
41f04d85
ES		 556 if (i == sbi->s_groups_count - 1)
557 last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
558 else
559 last_block = first_block +
560 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
561
1da177e4
LT		 562 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
563 gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
41f04d85
ES		 564 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
565 le32_to_cpu(gdp->bg_block_bitmap) > last_block)
1da177e4
LT		 566 {
567 ext2_error (sb, "ext2_check_descriptors",
568 "Block bitmap for group %d"
569 " not in group (block %lu)!",
570 i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
571 return 0;
572 }
41f04d85
ES		 573 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
574 le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
1da177e4
LT		 575 {
576 ext2_error (sb, "ext2_check_descriptors",
577 "Inode bitmap for group %d"
578 " not in group (block %lu)!",
579 i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
580 return 0;
581 }
41f04d85
ES		 582 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
583 le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >
584 last_block)
1da177e4
LT		 585 {
586 ext2_error (sb, "ext2_check_descriptors",
587 "Inode table for group %d"
588 " not in group (block %lu)!",
589 i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
590 return 0;
591 }
41f04d85 592 first_block += EXT2_BLOCKS_PER_GROUP(sb);
1da177e4
LT		 593 gdp++;
594 }
595 return 1;
596}
597
1da177e4
LT		 598/*
599 * Maximal file size. There is a direct, and {,double-,triple-}indirect
600 * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
601 * We need to be 1 filesystem block less than the 2^32 sector limit.
602 */
603static loff_t ext2_max_size(int bits)
604{
605 loff_t res = EXT2_NDIR_BLOCKS;
606 /* This constant is calculated to be the largest file size for a
607 * dense, 4k-blocksize file such that the total number of
608 * sectors in the file, including data and all indirect blocks,
609 * does not exceed 2^32. */
610 const loff_t upper_limit = 0x1ff7fffd000LL;
611
612 res += 1LL << (bits-2);
613 res += 1LL << (2*(bits-2));
614 res += 1LL << (3*(bits-2));
615 res <<= bits;
616 if (res > upper_limit)
617 res = upper_limit;
618 return res;
619}
620
621static unsigned long descriptor_loc(struct super_block *sb,
622 unsigned long logic_sb_block,
623 int nr)
624{
625 struct ext2_sb_info *sbi = EXT2_SB(sb);
626 unsigned long bg, first_data_block, first_meta_bg;
627 int has_super = 0;
628
629 first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
630 first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
631
632 if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
633 nr < first_meta_bg)
634 return (logic_sb_block + nr + 1);
635 bg = sbi->s_desc_per_block * nr;
636 if (ext2_bg_has_super(sb, bg))
637 has_super = 1;
638 return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
639}
640
641static int ext2_fill_super(struct super_block *sb, void *data, int silent)
642{
643 struct buffer_head * bh;
644 struct ext2_sb_info * sbi;
645 struct ext2_super_block * es;
646 struct inode *root;
647 unsigned long block;
648 unsigned long sb_block = get_sb_block(&data);
649 unsigned long logic_sb_block;
650 unsigned long offset = 0;
651 unsigned long def_mount_opts;
652 int blocksize = BLOCK_SIZE;
653 int db_count;
654 int i, j;
655 __le32 features;
656
f8314dc6 657 sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
1da177e4
LT		 658 if (!sbi)
659 return -ENOMEM;
660 sb->s_fs_info = sbi;
1da177e4
LT		 661
662 /*
663 * See what the current blocksize for the device is, and
664 * use that as the blocksize. Otherwise (or if the blocksize
665 * is smaller than the default) use the default.
666 * This is important for devices that have a hardware
667 * sectorsize that is larger than the default.
668 */
669 blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
670 if (!blocksize) {
671 printk ("EXT2-fs: unable to set blocksize\n");
672 goto failed_sbi;
673 }
674
675 /*
676 * If the superblock doesn't start on a hardware sector boundary,
677 * calculate the offset.
678 */
679 if (blocksize != BLOCK_SIZE) {
680 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
681 offset = (sb_block*BLOCK_SIZE) % blocksize;
682 } else {
683 logic_sb_block = sb_block;
684 }
685
686 if (!(bh = sb_bread(sb, logic_sb_block))) {
687 printk ("EXT2-fs: unable to read superblock\n");
688 goto failed_sbi;
689 }
690 /*
691 * Note: s_es must be initialized as soon as possible because
692 * some ext2 macro-instructions depend on its value
693 */
694 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
695 sbi->s_es = es;
696 sb->s_magic = le16_to_cpu(es->s_magic);
697
698 if (sb->s_magic != EXT2_SUPER_MAGIC)
699 goto cantfind_ext2;
700
701 /* Set defaults before we parse the mount options */
702 def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
703 if (def_mount_opts & EXT2_DEFM_DEBUG)
704 set_opt(sbi->s_mount_opt, DEBUG);
705 if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
706 set_opt(sbi->s_mount_opt, GRPID);
707 if (def_mount_opts & EXT2_DEFM_UID16)
708 set_opt(sbi->s_mount_opt, NO_UID32);
2e7842b8 709#ifdef CONFIG_EXT2_FS_XATTR
1da177e4
LT		 710 if (def_mount_opts & EXT2_DEFM_XATTR_USER)
711 set_opt(sbi->s_mount_opt, XATTR_USER);
2e7842b8
HD		 712#endif
713#ifdef CONFIG_EXT2_FS_POSIX_ACL
1da177e4
LT		 714 if (def_mount_opts & EXT2_DEFM_ACL)
715 set_opt(sbi->s_mount_opt, POSIX_ACL);
2e7842b8 716#endif
1da177e4
LT		 717
718 if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
719 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
720 else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
721 set_opt(sbi->s_mount_opt, ERRORS_RO);
5a2b4062
VA		 722 else
723 set_opt(sbi->s_mount_opt, ERRORS_CONT);
1da177e4
LT		 724
725 sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
726 sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
727
728 if (!parse_options ((char *) data, sbi))
729 goto failed_mount;
730
731 sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
732 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
733 MS_POSIXACL : 0);
734
6d79125b
CO		 735 ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
736 EXT2_MOUNT_XIP if not */
737
1da177e4
LT		 738 if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
739 (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
740 EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
741 EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
742 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
743 "running e2fsck is recommended\n");
744 /*
745 * Check feature flags regardless of the revision level, since we
746 * previously didn't change the revision level when setting the flags,
747 * so there is a chance incompat flags are set on a rev 0 filesystem.
748 */
749 features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
750 if (features) {
751 printk("EXT2-fs: %s: couldn't mount because of "
752 "unsupported optional features (%x).\n",
753 sb->s_id, le32_to_cpu(features));
754 goto failed_mount;
755 }
756 if (!(sb->s_flags & MS_RDONLY) &&
757 (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
758 printk("EXT2-fs: %s: couldn't mount RDWR because of "
759 "unsupported optional features (%x).\n",
760 sb->s_id, le32_to_cpu(features));
761 goto failed_mount;
762 }
763
764 blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
765
6d79125b
CO		 766 if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
767 (sb->s_blocksize != blocksize))) {
768 if (!silent)
769 printk("XIP: Unsupported blocksize\n");
770 goto failed_mount;
771 }
772
1da177e4
LT		 773 /* If the blocksize doesn't match, re-read the thing.. */
774 if (sb->s_blocksize != blocksize) {
775 brelse(bh);
776
777 if (!sb_set_blocksize(sb, blocksize)) {
778 printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
779 goto failed_sbi;
780 }
781
782 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
783 offset = (sb_block*BLOCK_SIZE) % blocksize;
784 bh = sb_bread(sb, logic_sb_block);
785 if(!bh) {
786 printk("EXT2-fs: Couldn't read superblock on "
787 "2nd try.\n");
788 goto failed_sbi;
789 }
790 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
791 sbi->s_es = es;
792 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
793 printk ("EXT2-fs: Magic mismatch, very weird !\n");
794 goto failed_mount;
795 }
796 }
797
798 sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
799
800 if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
801 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
802 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
803 } else {
804 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
805 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
806 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
807 (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
808 (sbi->s_inode_size > blocksize)) {
809 printk ("EXT2-fs: unsupported inode size: %d\n",
810 sbi->s_inode_size);
811 goto failed_mount;
812 }
813 }
814
815 sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
816 le32_to_cpu(es->s_log_frag_size);
817 if (sbi->s_frag_size == 0)
818 goto cantfind_ext2;
819 sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
820
821 sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
822 sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
823 sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
824
825 if (EXT2_INODE_SIZE(sb) == 0)
826 goto cantfind_ext2;
827 sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
607eb266 828 if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
1da177e4
LT		 829 goto cantfind_ext2;
830 sbi->s_itb_per_group = sbi->s_inodes_per_group /
831 sbi->s_inodes_per_block;
832 sbi->s_desc_per_block = sb->s_blocksize /
833 sizeof (struct ext2_group_desc);
834 sbi->s_sbh = bh;
835 sbi->s_mount_state = le16_to_cpu(es->s_state);
836 sbi->s_addr_per_block_bits =
f0d1b0b3 837 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
1da177e4 838 sbi->s_desc_per_block_bits =
f0d1b0b3 839 ilog2 (EXT2_DESC_PER_BLOCK(sb));
1da177e4
LT		 840
841 if (sb->s_magic != EXT2_SUPER_MAGIC)
842 goto cantfind_ext2;
843
844 if (sb->s_blocksize != bh->b_size) {
845 if (!silent)
846 printk ("VFS: Unsupported blocksize on dev "
847 "%s.\n", sb->s_id);
848 goto failed_mount;
849 }
850
851 if (sb->s_blocksize != sbi->s_frag_size) {
852 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
853 sbi->s_frag_size, sb->s_blocksize);
854 goto failed_mount;
855 }
856
857 if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
858 printk ("EXT2-fs: #blocks per group too big: %lu\n",
859 sbi->s_blocks_per_group);
860 goto failed_mount;
861 }
862 if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
863 printk ("EXT2-fs: #fragments per group too big: %lu\n",
864 sbi->s_frags_per_group);
865 goto failed_mount;
866 }
867 if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
868 printk ("EXT2-fs: #inodes per group too big: %lu\n",
869 sbi->s_inodes_per_group);
870 goto failed_mount;
871 }
872
873 if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
874 goto cantfind_ext2;
41f04d85
ES		 875 sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
876 le32_to_cpu(es->s_first_data_block) - 1)
877 / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
1da177e4
LT		 878 db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
879 EXT2_DESC_PER_BLOCK(sb);
880 sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
881 if (sbi->s_group_desc == NULL) {
882 printk ("EXT2-fs: not enough memory\n");
883 goto failed_mount;
884 }
1da177e4 885 bgl_lock_init(&sbi->s_blockgroup_lock);
dd00cc48 886 sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1da177e4
LT		 887 if (!sbi->s_debts) {
888 printk ("EXT2-fs: not enough memory\n");
889 goto failed_mount_group_desc;
890 }
1da177e4
LT		 891 for (i = 0; i < db_count; i++) {
892 block = descriptor_loc(sb, logic_sb_block, i);
893 sbi->s_group_desc[i] = sb_bread(sb, block);
894 if (!sbi->s_group_desc[i]) {
895 for (j = 0; j < i; j++)
896 brelse (sbi->s_group_desc[j]);
897 printk ("EXT2-fs: unable to read group descriptors\n");
898 goto failed_mount_group_desc;
899 }
900 }
901 if (!ext2_check_descriptors (sb)) {
902 printk ("EXT2-fs: group descriptors corrupted!\n");
1da177e4
LT		 903 goto failed_mount2;
904 }
905 sbi->s_gdb_count = db_count;
906 get_random_bytes(&sbi->s_next_generation, sizeof(u32));
907 spin_lock_init(&sbi->s_next_gen_lock);
0216bfcf
MC		 908
909 percpu_counter_init(&sbi->s_freeblocks_counter,
910 ext2_count_free_blocks(sb));
911 percpu_counter_init(&sbi->s_freeinodes_counter,
912 ext2_count_free_inodes(sb));
913 percpu_counter_init(&sbi->s_dirs_counter,
914 ext2_count_dirs(sb));
1da177e4
LT		 915 /*
916 * set up enough so that it can read an inode
917 */
918 sb->s_op = &ext2_sops;
919 sb->s_export_op = &ext2_export_ops;
920 sb->s_xattr = ext2_xattr_handlers;
921 root = iget(sb, EXT2_ROOT_INO);
922 sb->s_root = d_alloc_root(root);
923 if (!sb->s_root) {
924 iput(root);
925 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
0216bfcf 926 goto failed_mount3;
1da177e4
LT		 927 }
928 if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
929 dput(sb->s_root);
930 sb->s_root = NULL;
931 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
0216bfcf 932 goto failed_mount3;
1da177e4
LT		 933 }
934 if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
935 ext2_warning(sb, __FUNCTION__,
ec63f22d 936 "mounting ext3 filesystem as ext2");
1da177e4 937 ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
1da177e4
LT		 938 return 0;
939
940cantfind_ext2:
941 if (!silent)
942 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
943 sb->s_id);
944 goto failed_mount;
0216bfcf
MC		 945failed_mount3:
946 percpu_counter_destroy(&sbi->s_freeblocks_counter);
947 percpu_counter_destroy(&sbi->s_freeinodes_counter);
948 percpu_counter_destroy(&sbi->s_dirs_counter);
1da177e4
LT		 949failed_mount2:
950 for (i = 0; i < db_count; i++)
951 brelse(sbi->s_group_desc[i]);
952failed_mount_group_desc:
953 kfree(sbi->s_group_desc);
954 kfree(sbi->s_debts);
955failed_mount:
956 brelse(bh);
957failed_sbi:
958 sb->s_fs_info = NULL;
959 kfree(sbi);
960 return -EINVAL;
961}
962
963static void ext2_commit_super (struct super_block * sb,
964 struct ext2_super_block * es)
965{
966 es->s_wtime = cpu_to_le32(get_seconds());
967 mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
968 sb->s_dirt = 0;
969}
970
971static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
972{
973 es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
974 es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
975 es->s_wtime = cpu_to_le32(get_seconds());
976 mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
977 sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
978 sb->s_dirt = 0;
979}
980
981/*
982 * In the second extended file system, it is not necessary to
983 * write the super block since we use a mapping of the
984 * disk super block in a buffer.
985 *
986 * However, this function is still used to set the fs valid
987 * flags to 0. We need to set this flag to 0 since the fs
988 * may have been checked while mounted and e2fsck may have
989 * set s_state to EXT2_VALID_FS after some corrections.
990 */
991
992void ext2_write_super (struct super_block * sb)
993{
994 struct ext2_super_block * es;
995 lock_kernel();
996 if (!(sb->s_flags & MS_RDONLY)) {
997 es = EXT2_SB(sb)->s_es;
998
999 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
1000 ext2_debug ("setting valid to 0\n");
1001 es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
1002 ~EXT2_VALID_FS);
1003 es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1004 es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1005 es->s_mtime = cpu_to_le32(get_seconds());
1006 ext2_sync_super(sb, es);
1007 } else
1008 ext2_commit_super (sb, es);
1009 }
1010 sb->s_dirt = 0;
1011 unlock_kernel();
1012}
1013
1014static int ext2_remount (struct super_block * sb, int * flags, char * data)
1015{
1016 struct ext2_sb_info * sbi = EXT2_SB(sb);
1017 struct ext2_super_block * es;
6d79125b 1018 unsigned long old_mount_opt = sbi->s_mount_opt;
50a52234
JK		 1019 struct ext2_mount_options old_opts;
1020 unsigned long old_sb_flags;
1021 int err;
1022
1023 /* Store the old options */
1024 old_sb_flags = sb->s_flags;
1025 old_opts.s_mount_opt = sbi->s_mount_opt;
1026 old_opts.s_resuid = sbi->s_resuid;
1027 old_opts.s_resgid = sbi->s_resgid;
1da177e4
LT		 1028
1029 /*
1030 * Allow the "check" option to be passed as a remount option.
1031 */
50a52234
JK		 1032 if (!parse_options (data, sbi)) {
1033 err = -EINVAL;
1034 goto restore_opts;
1035 }
1da177e4
LT		 1036
1037 sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1038 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1039
266f5aa0
CO		 1040 ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1041 EXT2_MOUNT_XIP if not */
1042
1043 if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1044 printk("XIP: Unsupported blocksize\n");
ddc80bd7 1045 err = -EINVAL;
266f5aa0
CO		 1046 goto restore_opts;
1047 }
1048
1da177e4 1049 es = sbi->s_es;
6d79125b
CO		 1050 if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1051 (old_mount_opt & EXT2_MOUNT_XIP)) &&
1052 invalidate_inodes(sb))
1053 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1054 "xip remain in cache (no functional problem)");
1da177e4
LT		 1055 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1056 return 0;
1057 if (*flags & MS_RDONLY) {
1058 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1059 !(sbi->s_mount_state & EXT2_VALID_FS))
1060 return 0;
1061 /*
1062 * OK, we are remounting a valid rw partition rdonly, so set
1063 * the rdonly flag and then mark the partition as valid again.
1064 */
1065 es->s_state = cpu_to_le16(sbi->s_mount_state);
1066 es->s_mtime = cpu_to_le32(get_seconds());
1067 } else {
1068 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1069 ~EXT2_FEATURE_RO_COMPAT_SUPP);
1070 if (ret) {
1071 printk("EXT2-fs: %s: couldn't remount RDWR because of "
1072 "unsupported optional features (%x).\n",
1073 sb->s_id, le32_to_cpu(ret));
50a52234
JK		 1074 err = -EROFS;
1075 goto restore_opts;
1da177e4
LT		 1076 }
1077 /*
1078 * Mounting a RDONLY partition read-write, so reread and
1079 * store the current valid flag. (It may have been changed
1080 * by e2fsck since we originally mounted the partition.)
1081 */
1082 sbi->s_mount_state = le16_to_cpu(es->s_state);
1083 if (!ext2_setup_super (sb, es, 0))
1084 sb->s_flags &= ~MS_RDONLY;
1085 }
1086 ext2_sync_super(sb, es);
1087 return 0;
50a52234
JK		 1088restore_opts:
1089 sbi->s_mount_opt = old_opts.s_mount_opt;
1090 sbi->s_resuid = old_opts.s_resuid;
1091 sbi->s_resgid = old_opts.s_resgid;
1092 sb->s_flags = old_sb_flags;
1093 return err;
1da177e4
LT		 1094}
1095
726c3342 1096static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1da177e4 1097{
726c3342 1098 struct super_block *sb = dentry->d_sb;
1da177e4 1099 struct ext2_sb_info *sbi = EXT2_SB(sb);
e4fca01e 1100 struct ext2_super_block *es = sbi->s_es;
e4fca01e 1101 u64 fsid;
1da177e4
LT		 1102
1103 if (test_opt (sb, MINIX_DF))
2235219b
BP		 1104 sbi->s_overhead_last = 0;
1105 else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1106 unsigned long i, overhead = 0;
1107 smp_rmb();
1108
1da177e4 1109 /*
2235219b
BP		 1110 * Compute the overhead (FS structures). This is constant
1111 * for a given filesystem unless the number of block groups
1112 * changes so we cache the previous value until it does.
1da177e4
LT		 1113 */
1114
1115 /*
1116 * All of the blocks before first_data_block are
1117 * overhead
1118 */
e4fca01e 1119 overhead = le32_to_cpu(es->s_first_data_block);
1da177e4
LT		 1120
1121 /*
1122 * Add the overhead attributed to the superblock and
1123 * block group descriptors. If the sparse superblocks
1124 * feature is turned on, then not all groups have this.
1125 */
1126 for (i = 0; i < sbi->s_groups_count; i++)
1127 overhead += ext2_bg_has_super(sb, i) +
1128 ext2_bg_num_gdb(sb, i);
1129
1130 /*
1131 * Every block group has an inode bitmap, a block
1132 * bitmap, and an inode table.
1133 */
1134 overhead += (sbi->s_groups_count *
1135 (2 + sbi->s_itb_per_group));
2235219b
BP		 1136 sbi->s_overhead_last = overhead;
1137 smp_wmb();
1138 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1da177e4
LT		 1139 }
1140
1141 buf->f_type = EXT2_SUPER_MAGIC;
1142 buf->f_bsize = sb->s_blocksize;
2235219b 1143 buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1da177e4 1144 buf->f_bfree = ext2_count_free_blocks(sb);
2235219b 1145 es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
e4fca01e
PE		 1146 buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1147 if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1da177e4 1148 buf->f_bavail = 0;
e4fca01e
PE		 1149 buf->f_files = le32_to_cpu(es->s_inodes_count);
1150 buf->f_ffree = ext2_count_free_inodes(sb);
2235219b 1151 es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1da177e4 1152 buf->f_namelen = EXT2_NAME_LEN;
e4fca01e
PE		 1153 fsid = le64_to_cpup((void *)es->s_uuid) ^
1154 le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1155 buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1156 buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1da177e4
LT		 1157 return 0;
1158}
1159
454e2398
DH		 1160static int ext2_get_sb(struct file_system_type *fs_type,
1161 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1da177e4 1162{
454e2398 1163 return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1da177e4
LT		 1164}
1165
1166#ifdef CONFIG_QUOTA
1167
1168/* Read data from quotafile - avoid pagecache and such because we cannot afford
1169 * acquiring the locks... As quota files are never truncated and quota code
1170 * itself serializes the operations (and noone else should touch the files)
1171 * we don't have to be afraid of races */
1172static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1173 size_t len, loff_t off)
1174{
1175 struct inode *inode = sb_dqopt(sb)->files[type];
1176 sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1177 int err = 0;
1178 int offset = off & (sb->s_blocksize - 1);
1179 int tocopy;
1180 size_t toread;
1181 struct buffer_head tmp_bh;
1182 struct buffer_head *bh;
1183 loff_t i_size = i_size_read(inode);
1184
1185 if (off > i_size)
1186 return 0;
1187 if (off+len > i_size)
1188 len = i_size-off;
1189 toread = len;
1190 while (toread > 0) {
1191 tocopy = sb->s_blocksize - offset < toread ?
1192 sb->s_blocksize - offset : toread;
1193
1194 tmp_bh.b_state = 0;
1195 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1196 if (err)
1197 return err;
1198 if (!buffer_mapped(&tmp_bh)) /* A hole? */
1199 memset(data, 0, tocopy);
1200 else {
1201 bh = sb_bread(sb, tmp_bh.b_blocknr);
1202 if (!bh)
1203 return -EIO;
1204 memcpy(data, bh->b_data+offset, tocopy);
1205 brelse(bh);
1206 }
1207 offset = 0;
1208 toread -= tocopy;
1209 data += tocopy;
1210 blk++;
1211 }
1212 return len;
1213}
1214
1215/* Write to quotafile */
1216static ssize_t ext2_quota_write(struct super_block *sb, int type,
1217 const char *data, size_t len, loff_t off)
1218{
1219 struct inode *inode = sb_dqopt(sb)->files[type];
1220 sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1221 int err = 0;
1222 int offset = off & (sb->s_blocksize - 1);
1223 int tocopy;
1224 size_t towrite = len;
1225 struct buffer_head tmp_bh;
1226 struct buffer_head *bh;
1227
5c81a419 1228 mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1da177e4
LT		 1229 while (towrite > 0) {
1230 tocopy = sb->s_blocksize - offset < towrite ?
1231 sb->s_blocksize - offset : towrite;
1232
1233 tmp_bh.b_state = 0;
1234 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1235 if (err)
1236 goto out;
1237 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1238 bh = sb_bread(sb, tmp_bh.b_blocknr);
1239 else
1240 bh = sb_getblk(sb, tmp_bh.b_blocknr);
1241 if (!bh) {
1242 err = -EIO;
1243 goto out;
1244 }
1245 lock_buffer(bh);
1246 memcpy(bh->b_data+offset, data, tocopy);
1247 flush_dcache_page(bh->b_page);
1248 set_buffer_uptodate(bh);
1249 mark_buffer_dirty(bh);
1250 unlock_buffer(bh);
1251 brelse(bh);
1252 offset = 0;
1253 towrite -= tocopy;
1254 data += tocopy;
1255 blk++;
1256 }
1257out:
1258 if (len == towrite)
1259 return err;
1260 if (inode->i_size < off+len-towrite)
1261 i_size_write(inode, off+len-towrite);
1262 inode->i_version++;
1263 inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1264 mark_inode_dirty(inode);
1b1dcc1b 1265 mutex_unlock(&inode->i_mutex);
1da177e4
LT		 1266 return len - towrite;
1267}
1268
1269#endif
1270
1271static struct file_system_type ext2_fs_type = {
1272 .owner = THIS_MODULE,
1273 .name = "ext2",
1274 .get_sb = ext2_get_sb,
1275 .kill_sb = kill_block_super,
1276 .fs_flags = FS_REQUIRES_DEV,
1277};
1278
1279static int __init init_ext2_fs(void)
1280{
1281 int err = init_ext2_xattr();
1282 if (err)
1283 return err;
1284 err = init_inodecache();
1285 if (err)
1286 goto out1;
1287 err = register_filesystem(&ext2_fs_type);
1288 if (err)
1289 goto out;
1290 return 0;
1291out:
1292 destroy_inodecache();
1293out1:
1294 exit_ext2_xattr();
1295 return err;
1296}
1297
1298static void __exit exit_ext2_fs(void)
1299{
1300 unregister_filesystem(&ext2_fs_type);
1301 destroy_inodecache();
1302 exit_ext2_xattr();
1303}
1304
1305module_init(init_ext2_fs)
1306module_exit(exit_ext2_fs)
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