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aufs: possible bugfix, allow the nested aufsd between several aufs mounts
[zen-stable.git] / fs / ext2 / super.c
blob0090595beb28de8243cc6cfd2437dd007c6a7a69
1 /*
2 * linux/fs/ext2/super.c
3 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 *
9 * from
10 *
11 * linux/fs/minix/inode.c
12 *
13 * Copyright (C) 1991, 1992 Linus Torvalds
14 *
15 * Big-endian to little-endian byte-swapping/bitmaps by
16 * David S. Miller (davem@caip.rutgers.edu), 1995
17 */
18
19 #include <linux/module.h>
20 #include <linux/string.h>
21 #include <linux/fs.h>
22 #include <linux/slab.h>
23 #include <linux/init.h>
24 #include <linux/blkdev.h>
25 #include <linux/parser.h>
26 #include <linux/random.h>
27 #include <linux/buffer_head.h>
28 #include <linux/exportfs.h>
29 #include <linux/vfs.h>
30 #include <linux/seq_file.h>
31 #include <linux/mount.h>
32 #include <linux/log2.h>
33 #include <linux/quotaops.h>
34 #include <asm/uaccess.h>
35 #include "ext2.h"
36 #include "xattr.h"
37 #include "acl.h"
38 #include "xip.h"
39
40 static void ext2_sync_super(struct super_block *sb,
41 struct ext2_super_block *es, int wait);
42 static int ext2_remount (struct super_block * sb, int * flags, char * data);
43 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
44 static int ext2_sync_fs(struct super_block *sb, int wait);
45
46 void ext2_error(struct super_block *sb, const char *function,
47 const char *fmt, ...)
48 {
49 struct va_format vaf;
50 va_list args;
51 struct ext2_sb_info *sbi = EXT2_SB(sb);
52 struct ext2_super_block *es = sbi->s_es;
53
54 if (!(sb->s_flags & MS_RDONLY)) {
55 spin_lock(&sbi->s_lock);
56 sbi->s_mount_state |= EXT2_ERROR_FS;
57 es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
58 spin_unlock(&sbi->s_lock);
59 ext2_sync_super(sb, es, 1);
60 }
61
62 va_start(args, fmt);
63
64 vaf.fmt = fmt;
65 vaf.va = &args;
66
67 printk(KERN_CRIT "EXT2-fs (%s): error: %s: %pV\n",
68 sb->s_id, function, &vaf);
69
70 va_end(args);
71
72 if (test_opt(sb, ERRORS_PANIC))
73 panic("EXT2-fs: panic from previous error\n");
74 if (test_opt(sb, ERRORS_RO)) {
75 ext2_msg(sb, KERN_CRIT,
76 "error: remounting filesystem read-only");
77 sb->s_flags |= MS_RDONLY;
78 }
79 }
80
81 void ext2_msg(struct super_block *sb, const char *prefix,
82 const char *fmt, ...)
83 {
84 struct va_format vaf;
85 va_list args;
86
87 va_start(args, fmt);
88
89 vaf.fmt = fmt;
90 vaf.va = &args;
91
92 printk("%sEXT2-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
93
94 va_end(args);
95 }
96
97 /*
98 * This must be called with sbi->s_lock held.
99 */
100 void ext2_update_dynamic_rev(struct super_block *sb)
101 {
102 struct ext2_super_block *es = EXT2_SB(sb)->s_es;
103
104 if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
105 return;
106
107 ext2_msg(sb, KERN_WARNING,
108 "warning: updating to rev %d because of "
109 "new feature flag, running e2fsck is recommended",
110 EXT2_DYNAMIC_REV);
111
112 es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
113 es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
114 es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
115 /* leave es->s_feature_*compat flags alone */
116 /* es->s_uuid will be set by e2fsck if empty */
117
118 /*
119 * The rest of the superblock fields should be zero, and if not it
120 * means they are likely already in use, so leave them alone. We
121 * can leave it up to e2fsck to clean up any inconsistencies there.
122 */
123 }
124
125 static void ext2_put_super (struct super_block * sb)
126 {
127 int db_count;
128 int i;
129 struct ext2_sb_info *sbi = EXT2_SB(sb);
130
131 dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
132
133 if (sb->s_dirt)
134 ext2_write_super(sb);
135
136 ext2_xattr_put_super(sb);
137 if (!(sb->s_flags & MS_RDONLY)) {
138 struct ext2_super_block *es = sbi->s_es;
139
140 spin_lock(&sbi->s_lock);
141 es->s_state = cpu_to_le16(sbi->s_mount_state);
142 spin_unlock(&sbi->s_lock);
143 ext2_sync_super(sb, es, 1);
144 }
145 db_count = sbi->s_gdb_count;
146 for (i = 0; i < db_count; i++)
147 if (sbi->s_group_desc[i])
148 brelse (sbi->s_group_desc[i]);
149 kfree(sbi->s_group_desc);
150 kfree(sbi->s_debts);
151 percpu_counter_destroy(&sbi->s_freeblocks_counter);
152 percpu_counter_destroy(&sbi->s_freeinodes_counter);
153 percpu_counter_destroy(&sbi->s_dirs_counter);
154 brelse (sbi->s_sbh);
155 sb->s_fs_info = NULL;
156 kfree(sbi->s_blockgroup_lock);
157 kfree(sbi);
158 }
159
160 static struct kmem_cache * ext2_inode_cachep;
161
162 static struct inode *ext2_alloc_inode(struct super_block *sb)
163 {
164 struct ext2_inode_info *ei;
165 ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
166 if (!ei)
167 return NULL;
168 ei->i_block_alloc_info = NULL;
169 ei->vfs_inode.i_version = 1;
170 return &ei->vfs_inode;
171 }
172
173 static void ext2_i_callback(struct rcu_head *head)
174 {
175 struct inode *inode = container_of(head, struct inode, i_rcu);
176 kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
177 }
178
179 static void ext2_destroy_inode(struct inode *inode)
180 {
181 call_rcu(&inode->i_rcu, ext2_i_callback);
182 }
183
184 static void init_once(void *foo)
185 {
186 struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
187
188 rwlock_init(&ei->i_meta_lock);
189 #ifdef CONFIG_EXT2_FS_XATTR
190 init_rwsem(&ei->xattr_sem);
191 #endif
192 mutex_init(&ei->truncate_mutex);
193 inode_init_once(&ei->vfs_inode);
194 }
195
196 static int init_inodecache(void)
197 {
198 ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
199 sizeof(struct ext2_inode_info),
200 0, (SLAB_RECLAIM_ACCOUNT|
201 SLAB_MEM_SPREAD),
202 init_once);
203 if (ext2_inode_cachep == NULL)
204 return -ENOMEM;
205 return 0;
206 }
207
208 static void destroy_inodecache(void)
209 {
210 kmem_cache_destroy(ext2_inode_cachep);
211 }
212
213 static int ext2_show_options(struct seq_file *seq, struct dentry *root)
214 {
215 struct super_block *sb = root->d_sb;
216 struct ext2_sb_info *sbi = EXT2_SB(sb);
217 struct ext2_super_block *es = sbi->s_es;
218 unsigned long def_mount_opts;
219
220 spin_lock(&sbi->s_lock);
221 def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
222
223 if (sbi->s_sb_block != 1)
224 seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
225 if (test_opt(sb, MINIX_DF))
226 seq_puts(seq, ",minixdf");
227 if (test_opt(sb, GRPID))
228 seq_puts(seq, ",grpid");
229 if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
230 seq_puts(seq, ",nogrpid");
231 if (sbi->s_resuid != EXT2_DEF_RESUID ||
232 le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
233 seq_printf(seq, ",resuid=%u", sbi->s_resuid);
234 }
235 if (sbi->s_resgid != EXT2_DEF_RESGID ||
236 le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
237 seq_printf(seq, ",resgid=%u", sbi->s_resgid);
238 }
239 if (test_opt(sb, ERRORS_RO)) {
240 int def_errors = le16_to_cpu(es->s_errors);
241
242 if (def_errors == EXT2_ERRORS_PANIC ||
243 def_errors == EXT2_ERRORS_CONTINUE) {
244 seq_puts(seq, ",errors=remount-ro");
245 }
246 }
247 if (test_opt(sb, ERRORS_CONT))
248 seq_puts(seq, ",errors=continue");
249 if (test_opt(sb, ERRORS_PANIC))
250 seq_puts(seq, ",errors=panic");
251 if (test_opt(sb, NO_UID32))
252 seq_puts(seq, ",nouid32");
253 if (test_opt(sb, DEBUG))
254 seq_puts(seq, ",debug");
255 if (test_opt(sb, OLDALLOC))
256 seq_puts(seq, ",oldalloc");
257
258 #ifdef CONFIG_EXT2_FS_XATTR
259 if (test_opt(sb, XATTR_USER))
260 seq_puts(seq, ",user_xattr");
261 if (!test_opt(sb, XATTR_USER) &&
262 (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
263 seq_puts(seq, ",nouser_xattr");
264 }
265 #endif
266
267 #ifdef CONFIG_EXT2_FS_POSIX_ACL
268 if (test_opt(sb, POSIX_ACL))
269 seq_puts(seq, ",acl");
270 if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
271 seq_puts(seq, ",noacl");
272 #endif
273
274 if (test_opt(sb, NOBH))
275 seq_puts(seq, ",nobh");
276
277 #if defined(CONFIG_QUOTA)
278 if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
279 seq_puts(seq, ",usrquota");
280
281 if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
282 seq_puts(seq, ",grpquota");
283 #endif
284
285 #if defined(CONFIG_EXT2_FS_XIP)
286 if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
287 seq_puts(seq, ",xip");
288 #endif
289
290 if (!test_opt(sb, RESERVATION))
291 seq_puts(seq, ",noreservation");
292
293 spin_unlock(&sbi->s_lock);
294 return 0;
295 }
296
297 #ifdef CONFIG_QUOTA
298 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
299 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
300 #endif
301
302 static const struct super_operations ext2_sops = {
303 .alloc_inode = ext2_alloc_inode,
304 .destroy_inode = ext2_destroy_inode,
305 .write_inode = ext2_write_inode,
306 .evict_inode = ext2_evict_inode,
307 .put_super = ext2_put_super,
308 .write_super = ext2_write_super,
309 .sync_fs = ext2_sync_fs,
310 .statfs = ext2_statfs,
311 .remount_fs = ext2_remount,
312 .show_options = ext2_show_options,
313 #ifdef CONFIG_QUOTA
314 .quota_read = ext2_quota_read,
315 .quota_write = ext2_quota_write,
316 #endif
317 };
318
319 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
320 u64 ino, u32 generation)
321 {
322 struct inode *inode;
323
324 if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
325 return ERR_PTR(-ESTALE);
326 if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
327 return ERR_PTR(-ESTALE);
328
329 /*
330 * ext2_iget isn't quite right if the inode is currently unallocated!
331 * However ext2_iget currently does appropriate checks to handle stale
332 * inodes so everything is OK.
333 */
334 inode = ext2_iget(sb, ino);
335 if (IS_ERR(inode))
336 return ERR_CAST(inode);
337 if (generation && inode->i_generation != generation) {
338 /* we didn't find the right inode.. */
339 iput(inode);
340 return ERR_PTR(-ESTALE);
341 }
342 return inode;
343 }
344
345 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
346 int fh_len, int fh_type)
347 {
348 return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
349 ext2_nfs_get_inode);
350 }
351
352 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
353 int fh_len, int fh_type)
354 {
355 return generic_fh_to_parent(sb, fid, fh_len, fh_type,
356 ext2_nfs_get_inode);
357 }
358
359 /* Yes, most of these are left as NULL!!
360 * A NULL value implies the default, which works with ext2-like file
361 * systems, but can be improved upon.
362 * Currently only get_parent is required.
363 */
364 static const struct export_operations ext2_export_ops = {
365 .fh_to_dentry = ext2_fh_to_dentry,
366 .fh_to_parent = ext2_fh_to_parent,
367 .get_parent = ext2_get_parent,
368 };
369
370 static unsigned long get_sb_block(void **data)
371 {
372 unsigned long sb_block;
373 char *options = (char *) *data;
374
375 if (!options || strncmp(options, "sb=", 3) != 0)
376 return 1; /* Default location */
377 options += 3;
378 sb_block = simple_strtoul(options, &options, 0);
379 if (*options && *options != ',') {
380 printk("EXT2-fs: Invalid sb specification: %s\n",
381 (char *) *data);
382 return 1;
383 }
384 if (*options == ',')
385 options++;
386 *data = (void *) options;
387 return sb_block;
388 }
389
390 enum {
391 Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
392 Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
393 Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
394 Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
395 Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
396 Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
397 };
398
399 static const match_table_t tokens = {
400 {Opt_bsd_df, "bsddf"},
401 {Opt_minix_df, "minixdf"},
402 {Opt_grpid, "grpid"},
403 {Opt_grpid, "bsdgroups"},
404 {Opt_nogrpid, "nogrpid"},
405 {Opt_nogrpid, "sysvgroups"},
406 {Opt_resgid, "resgid=%u"},
407 {Opt_resuid, "resuid=%u"},
408 {Opt_sb, "sb=%u"},
409 {Opt_err_cont, "errors=continue"},
410 {Opt_err_panic, "errors=panic"},
411 {Opt_err_ro, "errors=remount-ro"},
412 {Opt_nouid32, "nouid32"},
413 {Opt_nocheck, "check=none"},
414 {Opt_nocheck, "nocheck"},
415 {Opt_debug, "debug"},
416 {Opt_oldalloc, "oldalloc"},
417 {Opt_orlov, "orlov"},
418 {Opt_nobh, "nobh"},
419 {Opt_user_xattr, "user_xattr"},
420 {Opt_nouser_xattr, "nouser_xattr"},
421 {Opt_acl, "acl"},
422 {Opt_noacl, "noacl"},
423 {Opt_xip, "xip"},
424 {Opt_grpquota, "grpquota"},
425 {Opt_ignore, "noquota"},
426 {Opt_quota, "quota"},
427 {Opt_usrquota, "usrquota"},
428 {Opt_reservation, "reservation"},
429 {Opt_noreservation, "noreservation"},
430 {Opt_err, NULL}
431 };
432
433 static int parse_options(char *options, struct super_block *sb)
434 {
435 char *p;
436 struct ext2_sb_info *sbi = EXT2_SB(sb);
437 substring_t args[MAX_OPT_ARGS];
438 int option;
439
440 if (!options)
441 return 1;
442
443 while ((p = strsep (&options, ",")) != NULL) {
444 int token;
445 if (!*p)
446 continue;
447
448 token = match_token(p, tokens, args);
449 switch (token) {
450 case Opt_bsd_df:
451 clear_opt (sbi->s_mount_opt, MINIX_DF);
452 break;
453 case Opt_minix_df:
454 set_opt (sbi->s_mount_opt, MINIX_DF);
455 break;
456 case Opt_grpid:
457 set_opt (sbi->s_mount_opt, GRPID);
458 break;
459 case Opt_nogrpid:
460 clear_opt (sbi->s_mount_opt, GRPID);
461 break;
462 case Opt_resuid:
463 if (match_int(&args[0], &option))
464 return 0;
465 sbi->s_resuid = option;
466 break;
467 case Opt_resgid:
468 if (match_int(&args[0], &option))
469 return 0;
470 sbi->s_resgid = option;
471 break;
472 case Opt_sb:
473 /* handled by get_sb_block() instead of here */
474 /* *sb_block = match_int(&args[0]); */
475 break;
476 case Opt_err_panic:
477 clear_opt (sbi->s_mount_opt, ERRORS_CONT);
478 clear_opt (sbi->s_mount_opt, ERRORS_RO);
479 set_opt (sbi->s_mount_opt, ERRORS_PANIC);
480 break;
481 case Opt_err_ro:
482 clear_opt (sbi->s_mount_opt, ERRORS_CONT);
483 clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
484 set_opt (sbi->s_mount_opt, ERRORS_RO);
485 break;
486 case Opt_err_cont:
487 clear_opt (sbi->s_mount_opt, ERRORS_RO);
488 clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
489 set_opt (sbi->s_mount_opt, ERRORS_CONT);
490 break;
491 case Opt_nouid32:
492 set_opt (sbi->s_mount_opt, NO_UID32);
493 break;
494 case Opt_nocheck:
495 clear_opt (sbi->s_mount_opt, CHECK);
496 break;
497 case Opt_debug:
498 set_opt (sbi->s_mount_opt, DEBUG);
499 break;
500 case Opt_oldalloc:
501 set_opt (sbi->s_mount_opt, OLDALLOC);
502 break;
503 case Opt_orlov:
504 clear_opt (sbi->s_mount_opt, OLDALLOC);
505 break;
506 case Opt_nobh:
507 set_opt (sbi->s_mount_opt, NOBH);
508 break;
509 #ifdef CONFIG_EXT2_FS_XATTR
510 case Opt_user_xattr:
511 set_opt (sbi->s_mount_opt, XATTR_USER);
512 break;
513 case Opt_nouser_xattr:
514 clear_opt (sbi->s_mount_opt, XATTR_USER);
515 break;
516 #else
517 case Opt_user_xattr:
518 case Opt_nouser_xattr:
519 ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
520 "not supported");
521 break;
522 #endif
523 #ifdef CONFIG_EXT2_FS_POSIX_ACL
524 case Opt_acl:
525 set_opt(sbi->s_mount_opt, POSIX_ACL);
526 break;
527 case Opt_noacl:
528 clear_opt(sbi->s_mount_opt, POSIX_ACL);
529 break;
530 #else
531 case Opt_acl:
532 case Opt_noacl:
533 ext2_msg(sb, KERN_INFO,
534 "(no)acl options not supported");
535 break;
536 #endif
537 case Opt_xip:
538 #ifdef CONFIG_EXT2_FS_XIP
539 set_opt (sbi->s_mount_opt, XIP);
540 #else
541 ext2_msg(sb, KERN_INFO, "xip option not supported");
542 #endif
543 break;
544
545 #if defined(CONFIG_QUOTA)
546 case Opt_quota:
547 case Opt_usrquota:
548 set_opt(sbi->s_mount_opt, USRQUOTA);
549 break;
550
551 case Opt_grpquota:
552 set_opt(sbi->s_mount_opt, GRPQUOTA);
553 break;
554 #else
555 case Opt_quota:
556 case Opt_usrquota:
557 case Opt_grpquota:
558 ext2_msg(sb, KERN_INFO,
559 "quota operations not supported");
560 break;
561 #endif
562
563 case Opt_reservation:
564 set_opt(sbi->s_mount_opt, RESERVATION);
565 ext2_msg(sb, KERN_INFO, "reservations ON");
566 break;
567 case Opt_noreservation:
568 clear_opt(sbi->s_mount_opt, RESERVATION);
569 ext2_msg(sb, KERN_INFO, "reservations OFF");
570 break;
571 case Opt_ignore:
572 break;
573 default:
574 return 0;
575 }
576 }
577 return 1;
578 }
579
580 static int ext2_setup_super (struct super_block * sb,
581 struct ext2_super_block * es,
582 int read_only)
583 {
584 int res = 0;
585 struct ext2_sb_info *sbi = EXT2_SB(sb);
586
587 if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
588 ext2_msg(sb, KERN_ERR,
589 "error: revision level too high, "
590 "forcing read-only mode");
591 res = MS_RDONLY;
592 }
593 if (read_only)
594 return res;
595 if (!(sbi->s_mount_state & EXT2_VALID_FS))
596 ext2_msg(sb, KERN_WARNING,
597 "warning: mounting unchecked fs, "
598 "running e2fsck is recommended");
599 else if ((sbi->s_mount_state & EXT2_ERROR_FS))
600 ext2_msg(sb, KERN_WARNING,
601 "warning: mounting fs with errors, "
602 "running e2fsck is recommended");
603 else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
604 le16_to_cpu(es->s_mnt_count) >=
605 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
606 ext2_msg(sb, KERN_WARNING,
607 "warning: maximal mount count reached, "
608 "running e2fsck is recommended");
609 else if (le32_to_cpu(es->s_checkinterval) &&
610 (le32_to_cpu(es->s_lastcheck) +
611 le32_to_cpu(es->s_checkinterval) <= get_seconds()))
612 ext2_msg(sb, KERN_WARNING,
613 "warning: checktime reached, "
614 "running e2fsck is recommended");
615 if (!le16_to_cpu(es->s_max_mnt_count))
616 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
617 le16_add_cpu(&es->s_mnt_count, 1);
618 if (test_opt (sb, DEBUG))
619 ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
620 "bpg=%lu, ipg=%lu, mo=%04lx]",
621 EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
622 sbi->s_frag_size,
623 sbi->s_groups_count,
624 EXT2_BLOCKS_PER_GROUP(sb),
625 EXT2_INODES_PER_GROUP(sb),
626 sbi->s_mount_opt);
627 return res;
628 }
629
630 static int ext2_check_descriptors(struct super_block *sb)
631 {
632 int i;
633 struct ext2_sb_info *sbi = EXT2_SB(sb);
634
635 ext2_debug ("Checking group descriptors");
636
637 for (i = 0; i < sbi->s_groups_count; i++) {
638 struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
639 ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
640 ext2_fsblk_t last_block;
641
642 if (i == sbi->s_groups_count - 1)
643 last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
644 else
645 last_block = first_block +
646 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
647
648 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
649 le32_to_cpu(gdp->bg_block_bitmap) > last_block)
650 {
651 ext2_error (sb, "ext2_check_descriptors",
652 "Block bitmap for group %d"
653 " not in group (block %lu)!",
654 i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
655 return 0;
656 }
657 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
658 le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
659 {
660 ext2_error (sb, "ext2_check_descriptors",
661 "Inode bitmap for group %d"
662 " not in group (block %lu)!",
663 i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
664 return 0;
665 }
666 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
667 le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
668 last_block)
669 {
670 ext2_error (sb, "ext2_check_descriptors",
671 "Inode table for group %d"
672 " not in group (block %lu)!",
673 i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
674 return 0;
675 }
676 }
677 return 1;
678 }
679
680 /*
681 * Maximal file size. There is a direct, and {,double-,triple-}indirect
682 * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
683 * We need to be 1 filesystem block less than the 2^32 sector limit.
684 */
685 static loff_t ext2_max_size(int bits)
686 {
687 loff_t res = EXT2_NDIR_BLOCKS;
688 int meta_blocks;
689 loff_t upper_limit;
690
691 /* This is calculated to be the largest file size for a
692 * dense, file such that the total number of
693 * sectors in the file, including data and all indirect blocks,
694 * does not exceed 2^32 -1
695 * __u32 i_blocks representing the total number of
696 * 512 bytes blocks of the file
697 */
698 upper_limit = (1LL << 32) - 1;
699
700 /* total blocks in file system block size */
701 upper_limit >>= (bits - 9);
702
703
704 /* indirect blocks */
705 meta_blocks = 1;
706 /* double indirect blocks */
707 meta_blocks += 1 + (1LL << (bits-2));
708 /* tripple indirect blocks */
709 meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
710
711 upper_limit -= meta_blocks;
712 upper_limit <<= bits;
713
714 res += 1LL << (bits-2);
715 res += 1LL << (2*(bits-2));
716 res += 1LL << (3*(bits-2));
717 res <<= bits;
718 if (res > upper_limit)
719 res = upper_limit;
720
721 if (res > MAX_LFS_FILESIZE)
722 res = MAX_LFS_FILESIZE;
723
724 return res;
725 }
726
727 static unsigned long descriptor_loc(struct super_block *sb,
728 unsigned long logic_sb_block,
729 int nr)
730 {
731 struct ext2_sb_info *sbi = EXT2_SB(sb);
732 unsigned long bg, first_meta_bg;
733 int has_super = 0;
734
735 first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
736
737 if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
738 nr < first_meta_bg)
739 return (logic_sb_block + nr + 1);
740 bg = sbi->s_desc_per_block * nr;
741 if (ext2_bg_has_super(sb, bg))
742 has_super = 1;
743
744 return ext2_group_first_block_no(sb, bg) + has_super;
745 }
746
747 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
748 {
749 struct buffer_head * bh;
750 struct ext2_sb_info * sbi;
751 struct ext2_super_block * es;
752 struct inode *root;
753 unsigned long block;
754 unsigned long sb_block = get_sb_block(&data);
755 unsigned long logic_sb_block;
756 unsigned long offset = 0;
757 unsigned long def_mount_opts;
758 long ret = -EINVAL;
759 int blocksize = BLOCK_SIZE;
760 int db_count;
761 int i, j;
762 __le32 features;
763 int err;
764
765 err = -ENOMEM;
766 sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
767 if (!sbi)
768 goto failed_unlock;
769
770 sbi->s_blockgroup_lock =
771 kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
772 if (!sbi->s_blockgroup_lock) {
773 kfree(sbi);
774 goto failed_unlock;
775 }
776 sb->s_fs_info = sbi;
777 sbi->s_sb_block = sb_block;
778
779 spin_lock_init(&sbi->s_lock);
780
781 /*
782 * See what the current blocksize for the device is, and
783 * use that as the blocksize. Otherwise (or if the blocksize
784 * is smaller than the default) use the default.
785 * This is important for devices that have a hardware
786 * sectorsize that is larger than the default.
787 */
788 blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
789 if (!blocksize) {
790 ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
791 goto failed_sbi;
792 }
793
794 /*
795 * If the superblock doesn't start on a hardware sector boundary,
796 * calculate the offset.
797 */
798 if (blocksize != BLOCK_SIZE) {
799 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
800 offset = (sb_block*BLOCK_SIZE) % blocksize;
801 } else {
802 logic_sb_block = sb_block;
803 }
804
805 if (!(bh = sb_bread(sb, logic_sb_block))) {
806 ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
807 goto failed_sbi;
808 }
809 /*
810 * Note: s_es must be initialized as soon as possible because
811 * some ext2 macro-instructions depend on its value
812 */
813 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
814 sbi->s_es = es;
815 sb->s_magic = le16_to_cpu(es->s_magic);
816
817 if (sb->s_magic != EXT2_SUPER_MAGIC)
818 goto cantfind_ext2;
819
820 /* Set defaults before we parse the mount options */
821 def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
822 if (def_mount_opts & EXT2_DEFM_DEBUG)
823 set_opt(sbi->s_mount_opt, DEBUG);
824 if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
825 set_opt(sbi->s_mount_opt, GRPID);
826 if (def_mount_opts & EXT2_DEFM_UID16)
827 set_opt(sbi->s_mount_opt, NO_UID32);
828 #ifdef CONFIG_EXT2_FS_XATTR
829 if (def_mount_opts & EXT2_DEFM_XATTR_USER)
830 set_opt(sbi->s_mount_opt, XATTR_USER);
831 #endif
832 #ifdef CONFIG_EXT2_FS_POSIX_ACL
833 if (def_mount_opts & EXT2_DEFM_ACL)
834 set_opt(sbi->s_mount_opt, POSIX_ACL);
835 #endif
836
837 if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
838 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
839 else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
840 set_opt(sbi->s_mount_opt, ERRORS_CONT);
841 else
842 set_opt(sbi->s_mount_opt, ERRORS_RO);
843
844 sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
845 sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
846
847 set_opt(sbi->s_mount_opt, RESERVATION);
848
849 if (!parse_options((char *) data, sb))
850 goto failed_mount;
851
852 sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
853 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
854 MS_POSIXACL : 0);
855
856 ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
857 EXT2_MOUNT_XIP if not */
858
859 if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
860 (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
861 EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
862 EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
863 ext2_msg(sb, KERN_WARNING,
864 "warning: feature flags set on rev 0 fs, "
865 "running e2fsck is recommended");
866 /*
867 * Check feature flags regardless of the revision level, since we
868 * previously didn't change the revision level when setting the flags,
869 * so there is a chance incompat flags are set on a rev 0 filesystem.
870 */
871 features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
872 if (features) {
873 ext2_msg(sb, KERN_ERR, "error: couldn't mount because of "
874 "unsupported optional features (%x)",
875 le32_to_cpu(features));
876 goto failed_mount;
877 }
878 if (!(sb->s_flags & MS_RDONLY) &&
879 (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
880 ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
881 "unsupported optional features (%x)",
882 le32_to_cpu(features));
883 goto failed_mount;
884 }
885
886 blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
887
888 if (ext2_use_xip(sb) && blocksize != PAGE_SIZE) {
889 if (!silent)
890 ext2_msg(sb, KERN_ERR,
891 "error: unsupported blocksize for xip");
892 goto failed_mount;
893 }
894
895 /* If the blocksize doesn't match, re-read the thing.. */
896 if (sb->s_blocksize != blocksize) {
897 brelse(bh);
898
899 if (!sb_set_blocksize(sb, blocksize)) {
900 ext2_msg(sb, KERN_ERR,
901 "error: bad blocksize %d", blocksize);
902 goto failed_sbi;
903 }
904
905 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
906 offset = (sb_block*BLOCK_SIZE) % blocksize;
907 bh = sb_bread(sb, logic_sb_block);
908 if(!bh) {
909 ext2_msg(sb, KERN_ERR, "error: couldn't read"
910 "superblock on 2nd try");
911 goto failed_sbi;
912 }
913 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
914 sbi->s_es = es;
915 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
916 ext2_msg(sb, KERN_ERR, "error: magic mismatch");
917 goto failed_mount;
918 }
919 }
920
921 sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
922
923 if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
924 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
925 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
926 } else {
927 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
928 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
929 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
930 !is_power_of_2(sbi->s_inode_size) ||
931 (sbi->s_inode_size > blocksize)) {
932 ext2_msg(sb, KERN_ERR,
933 "error: unsupported inode size: %d",
934 sbi->s_inode_size);
935 goto failed_mount;
936 }
937 }
938
939 sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
940 le32_to_cpu(es->s_log_frag_size);
941 if (sbi->s_frag_size == 0)
942 goto cantfind_ext2;
943 sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
944
945 sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
946 sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
947 sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
948
949 if (EXT2_INODE_SIZE(sb) == 0)
950 goto cantfind_ext2;
951 sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
952 if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
953 goto cantfind_ext2;
954 sbi->s_itb_per_group = sbi->s_inodes_per_group /
955 sbi->s_inodes_per_block;
956 sbi->s_desc_per_block = sb->s_blocksize /
957 sizeof (struct ext2_group_desc);
958 sbi->s_sbh = bh;
959 sbi->s_mount_state = le16_to_cpu(es->s_state);
960 sbi->s_addr_per_block_bits =
961 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
962 sbi->s_desc_per_block_bits =
963 ilog2 (EXT2_DESC_PER_BLOCK(sb));
964
965 if (sb->s_magic != EXT2_SUPER_MAGIC)
966 goto cantfind_ext2;
967
968 if (sb->s_blocksize != bh->b_size) {
969 if (!silent)
970 ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
971 goto failed_mount;
972 }
973
974 if (sb->s_blocksize != sbi->s_frag_size) {
975 ext2_msg(sb, KERN_ERR,
976 "error: fragsize %lu != blocksize %lu"
977 "(not supported yet)",
978 sbi->s_frag_size, sb->s_blocksize);
979 goto failed_mount;
980 }
981
982 if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
983 ext2_msg(sb, KERN_ERR,
984 "error: #blocks per group too big: %lu",
985 sbi->s_blocks_per_group);
986 goto failed_mount;
987 }
988 if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
989 ext2_msg(sb, KERN_ERR,
990 "error: #fragments per group too big: %lu",
991 sbi->s_frags_per_group);
992 goto failed_mount;
993 }
994 if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
995 ext2_msg(sb, KERN_ERR,
996 "error: #inodes per group too big: %lu",
997 sbi->s_inodes_per_group);
998 goto failed_mount;
999 }
1000
1001 if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
1002 goto cantfind_ext2;
1003 sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
1004 le32_to_cpu(es->s_first_data_block) - 1)
1005 / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
1006 db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
1007 EXT2_DESC_PER_BLOCK(sb);
1008 sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
1009 if (sbi->s_group_desc == NULL) {
1010 ext2_msg(sb, KERN_ERR, "error: not enough memory");
1011 goto failed_mount;
1012 }
1013 bgl_lock_init(sbi->s_blockgroup_lock);
1014 sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1015 if (!sbi->s_debts) {
1016 ext2_msg(sb, KERN_ERR, "error: not enough memory");
1017 goto failed_mount_group_desc;
1018 }
1019 for (i = 0; i < db_count; i++) {
1020 block = descriptor_loc(sb, logic_sb_block, i);
1021 sbi->s_group_desc[i] = sb_bread(sb, block);
1022 if (!sbi->s_group_desc[i]) {
1023 for (j = 0; j < i; j++)
1024 brelse (sbi->s_group_desc[j]);
1025 ext2_msg(sb, KERN_ERR,
1026 "error: unable to read group descriptors");
1027 goto failed_mount_group_desc;
1028 }
1029 }
1030 if (!ext2_check_descriptors (sb)) {
1031 ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1032 goto failed_mount2;
1033 }
1034 sbi->s_gdb_count = db_count;
1035 get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1036 spin_lock_init(&sbi->s_next_gen_lock);
1037
1038 /* per fileystem reservation list head & lock */
1039 spin_lock_init(&sbi->s_rsv_window_lock);
1040 sbi->s_rsv_window_root = RB_ROOT;
1041 /*
1042 * Add a single, static dummy reservation to the start of the
1043 * reservation window list --- it gives us a placeholder for
1044 * append-at-start-of-list which makes the allocation logic
1045 * _much_ simpler.
1046 */
1047 sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1048 sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1049 sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1050 sbi->s_rsv_window_head.rsv_goal_size = 0;
1051 ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1052
1053 err = percpu_counter_init(&sbi->s_freeblocks_counter,
1054 ext2_count_free_blocks(sb));
1055 if (!err) {
1056 err = percpu_counter_init(&sbi->s_freeinodes_counter,
1057 ext2_count_free_inodes(sb));
1058 }
1059 if (!err) {
1060 err = percpu_counter_init(&sbi->s_dirs_counter,
1061 ext2_count_dirs(sb));
1062 }
1063 if (err) {
1064 ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1065 goto failed_mount3;
1066 }
1067 /*
1068 * set up enough so that it can read an inode
1069 */
1070 sb->s_op = &ext2_sops;
1071 sb->s_export_op = &ext2_export_ops;
1072 sb->s_xattr = ext2_xattr_handlers;
1073
1074 #ifdef CONFIG_QUOTA
1075 sb->dq_op = &dquot_operations;
1076 sb->s_qcop = &dquot_quotactl_ops;
1077 #endif
1078
1079 root = ext2_iget(sb, EXT2_ROOT_INO);
1080 if (IS_ERR(root)) {
1081 ret = PTR_ERR(root);
1082 goto failed_mount3;
1083 }
1084 if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1085 iput(root);
1086 ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1087 goto failed_mount3;
1088 }
1089
1090 sb->s_root = d_alloc_root(root);
1091 if (!sb->s_root) {
1092 iput(root);
1093 ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1094 ret = -ENOMEM;
1095 goto failed_mount3;
1096 }
1097 if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1098 ext2_msg(sb, KERN_WARNING,
1099 "warning: mounting ext3 filesystem as ext2");
1100 if (ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY))
1101 sb->s_flags |= MS_RDONLY;
1102 ext2_write_super(sb);
1103 return 0;
1104
1105 cantfind_ext2:
1106 if (!silent)
1107 ext2_msg(sb, KERN_ERR,
1108 "error: can't find an ext2 filesystem on dev %s.",
1109 sb->s_id);
1110 goto failed_mount;
1111 failed_mount3:
1112 percpu_counter_destroy(&sbi->s_freeblocks_counter);
1113 percpu_counter_destroy(&sbi->s_freeinodes_counter);
1114 percpu_counter_destroy(&sbi->s_dirs_counter);
1115 failed_mount2:
1116 for (i = 0; i < db_count; i++)
1117 brelse(sbi->s_group_desc[i]);
1118 failed_mount_group_desc:
1119 kfree(sbi->s_group_desc);
1120 kfree(sbi->s_debts);
1121 failed_mount:
1122 brelse(bh);
1123 failed_sbi:
1124 sb->s_fs_info = NULL;
1125 kfree(sbi->s_blockgroup_lock);
1126 kfree(sbi);
1127 failed_unlock:
1128 return ret;
1129 }
1130
1131 static void ext2_clear_super_error(struct super_block *sb)
1132 {
1133 struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1134
1135 if (buffer_write_io_error(sbh)) {
1136 /*
1137 * Oh, dear. A previous attempt to write the
1138 * superblock failed. This could happen because the
1139 * USB device was yanked out. Or it could happen to
1140 * be a transient write error and maybe the block will
1141 * be remapped. Nothing we can do but to retry the
1142 * write and hope for the best.
1143 */
1144 ext2_msg(sb, KERN_ERR,
1145 "previous I/O error to superblock detected\n");
1146 clear_buffer_write_io_error(sbh);
1147 set_buffer_uptodate(sbh);
1148 }
1149 }
1150
1151 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
1152 int wait)
1153 {
1154 ext2_clear_super_error(sb);
1155 spin_lock(&EXT2_SB(sb)->s_lock);
1156 es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1157 es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1158 es->s_wtime = cpu_to_le32(get_seconds());
1159 /* unlock before we do IO */
1160 spin_unlock(&EXT2_SB(sb)->s_lock);
1161 mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1162 if (wait)
1163 sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1164 sb->s_dirt = 0;
1165 }
1166
1167 /*
1168 * In the second extended file system, it is not necessary to
1169 * write the super block since we use a mapping of the
1170 * disk super block in a buffer.
1171 *
1172 * However, this function is still used to set the fs valid
1173 * flags to 0. We need to set this flag to 0 since the fs
1174 * may have been checked while mounted and e2fsck may have
1175 * set s_state to EXT2_VALID_FS after some corrections.
1176 */
1177 static int ext2_sync_fs(struct super_block *sb, int wait)
1178 {
1179 struct ext2_sb_info *sbi = EXT2_SB(sb);
1180 struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1181
1182 spin_lock(&sbi->s_lock);
1183 if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1184 ext2_debug("setting valid to 0\n");
1185 es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1186 }
1187 spin_unlock(&sbi->s_lock);
1188 ext2_sync_super(sb, es, wait);
1189 return 0;
1190 }
1191
1192
1193 void ext2_write_super(struct super_block *sb)
1194 {
1195 if (!(sb->s_flags & MS_RDONLY))
1196 ext2_sync_fs(sb, 1);
1197 else
1198 sb->s_dirt = 0;
1199 }
1200
1201 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1202 {
1203 struct ext2_sb_info * sbi = EXT2_SB(sb);
1204 struct ext2_super_block * es;
1205 unsigned long old_mount_opt = sbi->s_mount_opt;
1206 struct ext2_mount_options old_opts;
1207 unsigned long old_sb_flags;
1208 int err;
1209
1210 spin_lock(&sbi->s_lock);
1211
1212 /* Store the old options */
1213 old_sb_flags = sb->s_flags;
1214 old_opts.s_mount_opt = sbi->s_mount_opt;
1215 old_opts.s_resuid = sbi->s_resuid;
1216 old_opts.s_resgid = sbi->s_resgid;
1217
1218 /*
1219 * Allow the "check" option to be passed as a remount option.
1220 */
1221 if (!parse_options(data, sb)) {
1222 err = -EINVAL;
1223 goto restore_opts;
1224 }
1225
1226 sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1227 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1228
1229 ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1230 EXT2_MOUNT_XIP if not */
1231
1232 if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1233 ext2_msg(sb, KERN_WARNING,
1234 "warning: unsupported blocksize for xip");
1235 err = -EINVAL;
1236 goto restore_opts;
1237 }
1238
1239 es = sbi->s_es;
1240 if ((sbi->s_mount_opt ^ old_mount_opt) & EXT2_MOUNT_XIP) {
1241 ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1242 "xip flag with busy inodes while remounting");
1243 sbi->s_mount_opt &= ~EXT2_MOUNT_XIP;
1244 sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;
1245 }
1246 if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
1247 spin_unlock(&sbi->s_lock);
1248 return 0;
1249 }
1250 if (*flags & MS_RDONLY) {
1251 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1252 !(sbi->s_mount_state & EXT2_VALID_FS)) {
1253 spin_unlock(&sbi->s_lock);
1254 return 0;
1255 }
1256
1257 /*
1258 * OK, we are remounting a valid rw partition rdonly, so set
1259 * the rdonly flag and then mark the partition as valid again.
1260 */
1261 es->s_state = cpu_to_le16(sbi->s_mount_state);
1262 es->s_mtime = cpu_to_le32(get_seconds());
1263 spin_unlock(&sbi->s_lock);
1264
1265 err = dquot_suspend(sb, -1);
1266 if (err < 0) {
1267 spin_lock(&sbi->s_lock);
1268 goto restore_opts;
1269 }
1270
1271 ext2_sync_super(sb, es, 1);
1272 } else {
1273 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1274 ~EXT2_FEATURE_RO_COMPAT_SUPP);
1275 if (ret) {
1276 ext2_msg(sb, KERN_WARNING,
1277 "warning: couldn't remount RDWR because of "
1278 "unsupported optional features (%x).",
1279 le32_to_cpu(ret));
1280 err = -EROFS;
1281 goto restore_opts;
1282 }
1283 /*
1284 * Mounting a RDONLY partition read-write, so reread and
1285 * store the current valid flag. (It may have been changed
1286 * by e2fsck since we originally mounted the partition.)
1287 */
1288 sbi->s_mount_state = le16_to_cpu(es->s_state);
1289 if (!ext2_setup_super (sb, es, 0))
1290 sb->s_flags &= ~MS_RDONLY;
1291 spin_unlock(&sbi->s_lock);
1292
1293 ext2_write_super(sb);
1294
1295 dquot_resume(sb, -1);
1296 }
1297
1298 return 0;
1299 restore_opts:
1300 sbi->s_mount_opt = old_opts.s_mount_opt;
1301 sbi->s_resuid = old_opts.s_resuid;
1302 sbi->s_resgid = old_opts.s_resgid;
1303 sb->s_flags = old_sb_flags;
1304 spin_unlock(&sbi->s_lock);
1305 return err;
1306 }
1307
1308 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1309 {
1310 struct super_block *sb = dentry->d_sb;
1311 struct ext2_sb_info *sbi = EXT2_SB(sb);
1312 struct ext2_super_block *es = sbi->s_es;
1313 u64 fsid;
1314
1315 spin_lock(&sbi->s_lock);
1316
1317 if (test_opt (sb, MINIX_DF))
1318 sbi->s_overhead_last = 0;
1319 else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1320 unsigned long i, overhead = 0;
1321 smp_rmb();
1322
1323 /*
1324 * Compute the overhead (FS structures). This is constant
1325 * for a given filesystem unless the number of block groups
1326 * changes so we cache the previous value until it does.
1327 */
1328
1329 /*
1330 * All of the blocks before first_data_block are
1331 * overhead
1332 */
1333 overhead = le32_to_cpu(es->s_first_data_block);
1334
1335 /*
1336 * Add the overhead attributed to the superblock and
1337 * block group descriptors. If the sparse superblocks
1338 * feature is turned on, then not all groups have this.
1339 */
1340 for (i = 0; i < sbi->s_groups_count; i++)
1341 overhead += ext2_bg_has_super(sb, i) +
1342 ext2_bg_num_gdb(sb, i);
1343
1344 /*
1345 * Every block group has an inode bitmap, a block
1346 * bitmap, and an inode table.
1347 */
1348 overhead += (sbi->s_groups_count *
1349 (2 + sbi->s_itb_per_group));
1350 sbi->s_overhead_last = overhead;
1351 smp_wmb();
1352 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1353 }
1354
1355 buf->f_type = EXT2_SUPER_MAGIC;
1356 buf->f_bsize = sb->s_blocksize;
1357 buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1358 buf->f_bfree = ext2_count_free_blocks(sb);
1359 es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1360 buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1361 if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1362 buf->f_bavail = 0;
1363 buf->f_files = le32_to_cpu(es->s_inodes_count);
1364 buf->f_ffree = ext2_count_free_inodes(sb);
1365 es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1366 buf->f_namelen = EXT2_NAME_LEN;
1367 fsid = le64_to_cpup((void *)es->s_uuid) ^
1368 le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1369 buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1370 buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1371 spin_unlock(&sbi->s_lock);
1372 return 0;
1373 }
1374
1375 static struct dentry *ext2_mount(struct file_system_type *fs_type,
1376 int flags, const char *dev_name, void *data)
1377 {
1378 return mount_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1379 }
1380
1381 #ifdef CONFIG_QUOTA
1382
1383 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1384 * acquiring the locks... As quota files are never truncated and quota code
1385 * itself serializes the operations (and no one else should touch the files)
1386 * we don't have to be afraid of races */
1387 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1388 size_t len, loff_t off)
1389 {
1390 struct inode *inode = sb_dqopt(sb)->files[type];
1391 sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1392 int err = 0;
1393 int offset = off & (sb->s_blocksize - 1);
1394 int tocopy;
1395 size_t toread;
1396 struct buffer_head tmp_bh;
1397 struct buffer_head *bh;
1398 loff_t i_size = i_size_read(inode);
1399
1400 if (off > i_size)
1401 return 0;
1402 if (off+len > i_size)
1403 len = i_size-off;
1404 toread = len;
1405 while (toread > 0) {
1406 tocopy = sb->s_blocksize - offset < toread ?
1407 sb->s_blocksize - offset : toread;
1408
1409 tmp_bh.b_state = 0;
1410 tmp_bh.b_size = sb->s_blocksize;
1411 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1412 if (err < 0)
1413 return err;
1414 if (!buffer_mapped(&tmp_bh)) /* A hole? */
1415 memset(data, 0, tocopy);
1416 else {
1417 bh = sb_bread(sb, tmp_bh.b_blocknr);
1418 if (!bh)
1419 return -EIO;
1420 memcpy(data, bh->b_data+offset, tocopy);
1421 brelse(bh);
1422 }
1423 offset = 0;
1424 toread -= tocopy;
1425 data += tocopy;
1426 blk++;
1427 }
1428 return len;
1429 }
1430
1431 /* Write to quotafile */
1432 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1433 const char *data, size_t len, loff_t off)
1434 {
1435 struct inode *inode = sb_dqopt(sb)->files[type];
1436 sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1437 int err = 0;
1438 int offset = off & (sb->s_blocksize - 1);
1439 int tocopy;
1440 size_t towrite = len;
1441 struct buffer_head tmp_bh;
1442 struct buffer_head *bh;
1443
1444 mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1445 while (towrite > 0) {
1446 tocopy = sb->s_blocksize - offset < towrite ?
1447 sb->s_blocksize - offset : towrite;
1448
1449 tmp_bh.b_state = 0;
1450 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1451 if (err < 0)
1452 goto out;
1453 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1454 bh = sb_bread(sb, tmp_bh.b_blocknr);
1455 else
1456 bh = sb_getblk(sb, tmp_bh.b_blocknr);
1457 if (!bh) {
1458 err = -EIO;
1459 goto out;
1460 }
1461 lock_buffer(bh);
1462 memcpy(bh->b_data+offset, data, tocopy);
1463 flush_dcache_page(bh->b_page);
1464 set_buffer_uptodate(bh);
1465 mark_buffer_dirty(bh);
1466 unlock_buffer(bh);
1467 brelse(bh);
1468 offset = 0;
1469 towrite -= tocopy;
1470 data += tocopy;
1471 blk++;
1472 }
1473 out:
1474 if (len == towrite) {
1475 mutex_unlock(&inode->i_mutex);
1476 return err;
1477 }
1478 if (inode->i_size < off+len-towrite)
1479 i_size_write(inode, off+len-towrite);
1480 inode->i_version++;
1481 inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1482 mark_inode_dirty(inode);
1483 mutex_unlock(&inode->i_mutex);
1484 return len - towrite;
1485 }
1486
1487 #endif
1488
1489 static struct file_system_type ext2_fs_type = {
1490 .owner = THIS_MODULE,
1491 .name = "ext2",
1492 .mount = ext2_mount,
1493 .kill_sb = kill_block_super,
1494 .fs_flags = FS_REQUIRES_DEV,
1495 };
1496
1497 static int __init init_ext2_fs(void)
1498 {
1499 int err = init_ext2_xattr();
1500 if (err)
1501 return err;
1502 err = init_inodecache();
1503 if (err)
1504 goto out1;
1505 err = register_filesystem(&ext2_fs_type);
1506 if (err)
1507 goto out;
1508 return 0;
1509 out:
1510 destroy_inodecache();
1511 out1:
1512 exit_ext2_xattr();
1513 return err;
1514 }
1515
1516 static void __exit exit_ext2_fs(void)
1517 {
1518 unregister_filesystem(&ext2_fs_type);
1519 destroy_inodecache();
1520 exit_ext2_xattr();
1521 }
1522
1523 MODULE_AUTHOR("Remy Card and others");
1524 MODULE_DESCRIPTION("Second Extended Filesystem");
1525 MODULE_LICENSE("GPL");
1526 module_init(init_ext2_fs)
1527 module_exit(exit_ext2_fs)