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super.c
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1 /*
2  * linux/fs/ext2/super.c
3  *
4  * Copyright (C) 1992, 1993, 1994, 1995
5  * Remy Card ([email protected])
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 ([email protected]), 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 static int ext2_freeze(struct super_block *sb);
46 static int ext2_unfreeze(struct super_block *sb);
47 
48 void ext2_error(struct super_block *sb, const char *function,
49  const char *fmt, ...)
50 {
51  struct va_format vaf;
52  va_list args;
53  struct ext2_sb_info *sbi = EXT2_SB(sb);
54  struct ext2_super_block *es = sbi->s_es;
55 
56  if (!(sb->s_flags & MS_RDONLY)) {
57  spin_lock(&sbi->s_lock);
58  sbi->s_mount_state |= EXT2_ERROR_FS;
59  es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
60  spin_unlock(&sbi->s_lock);
61  ext2_sync_super(sb, es, 1);
62  }
63 
64  va_start(args, fmt);
65 
66  vaf.fmt = fmt;
67  vaf.va = &args;
68 
69  printk(KERN_CRIT "EXT2-fs (%s): error: %s: %pV\n",
70  sb->s_id, function, &vaf);
71 
72  va_end(args);
73 
74  if (test_opt(sb, ERRORS_PANIC))
75  panic("EXT2-fs: panic from previous error\n");
76  if (test_opt(sb, ERRORS_RO)) {
77  ext2_msg(sb, KERN_CRIT,
78  "error: remounting filesystem read-only");
79  sb->s_flags |= MS_RDONLY;
80  }
81 }
82 
83 void ext2_msg(struct super_block *sb, const char *prefix,
84  const char *fmt, ...)
85 {
86  struct va_format vaf;
87  va_list args;
88 
89  va_start(args, fmt);
90 
91  vaf.fmt = fmt;
92  vaf.va = &args;
93 
94  printk("%sEXT2-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
95 
96  va_end(args);
97 }
98 
99 /*
100  * This must be called with sbi->s_lock held.
101  */
102 void ext2_update_dynamic_rev(struct super_block *sb)
103 {
104  struct ext2_super_block *es = EXT2_SB(sb)->s_es;
105 
106  if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
107  return;
108 
109  ext2_msg(sb, KERN_WARNING,
110  "warning: updating to rev %d because of "
111  "new feature flag, running e2fsck is recommended",
112  EXT2_DYNAMIC_REV);
113 
114  es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
115  es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
116  es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
117  /* leave es->s_feature_*compat flags alone */
118  /* es->s_uuid will be set by e2fsck if empty */
119 
120  /*
121  * The rest of the superblock fields should be zero, and if not it
122  * means they are likely already in use, so leave them alone. We
123  * can leave it up to e2fsck to clean up any inconsistencies there.
124  */
125 }
126 
127 static void ext2_put_super (struct super_block * sb)
128 {
129  int db_count;
130  int i;
131  struct ext2_sb_info *sbi = EXT2_SB(sb);
132 
133  dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
134 
135  ext2_xattr_put_super(sb);
136  if (!(sb->s_flags & MS_RDONLY)) {
137  struct ext2_super_block *es = sbi->s_es;
138 
139  spin_lock(&sbi->s_lock);
140  es->s_state = cpu_to_le16(sbi->s_mount_state);
141  spin_unlock(&sbi->s_lock);
142  ext2_sync_super(sb, es, 1);
143  }
144  db_count = sbi->s_gdb_count;
145  for (i = 0; i < db_count; i++)
146  if (sbi->s_group_desc[i])
147  brelse (sbi->s_group_desc[i]);
148  kfree(sbi->s_group_desc);
149  kfree(sbi->s_debts);
150  percpu_counter_destroy(&sbi->s_freeblocks_counter);
151  percpu_counter_destroy(&sbi->s_freeinodes_counter);
152  percpu_counter_destroy(&sbi->s_dirs_counter);
153  brelse (sbi->s_sbh);
154  sb->s_fs_info = NULL;
155  kfree(sbi->s_blockgroup_lock);
156  kfree(sbi);
157 }
158 
159 static struct kmem_cache * ext2_inode_cachep;
160 
161 static struct inode *ext2_alloc_inode(struct super_block *sb)
162 {
163  struct ext2_inode_info *ei;
164  ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
165  if (!ei)
166  return NULL;
167  ei->i_block_alloc_info = NULL;
168  ei->vfs_inode.i_version = 1;
169  return &ei->vfs_inode;
170 }
171 
172 static void ext2_i_callback(struct rcu_head *head)
173 {
174  struct inode *inode = container_of(head, struct inode, i_rcu);
175  kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
176 }
177 
178 static void ext2_destroy_inode(struct inode *inode)
179 {
180  call_rcu(&inode->i_rcu, ext2_i_callback);
181 }
182 
183 static void init_once(void *foo)
184 {
185  struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
186 
187  rwlock_init(&ei->i_meta_lock);
188 #ifdef CONFIG_EXT2_FS_XATTR
189  init_rwsem(&ei->xattr_sem);
190 #endif
191  mutex_init(&ei->truncate_mutex);
192  inode_init_once(&ei->vfs_inode);
193 }
194 
195 static int init_inodecache(void)
196 {
197  ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
198  sizeof(struct ext2_inode_info),
199  0, (SLAB_RECLAIM_ACCOUNT|
200  SLAB_MEM_SPREAD),
201  init_once);
202  if (ext2_inode_cachep == NULL)
203  return -ENOMEM;
204  return 0;
205 }
206 
207 static void destroy_inodecache(void)
208 {
209  /*
210  * Make sure all delayed rcu free inodes are flushed before we
211  * destroy cache.
212  */
213  rcu_barrier();
214  kmem_cache_destroy(ext2_inode_cachep);
215 }
216 
217 static int ext2_show_options(struct seq_file *seq, struct dentry *root)
218 {
219  struct super_block *sb = root->d_sb;
220  struct ext2_sb_info *sbi = EXT2_SB(sb);
221  struct ext2_super_block *es = sbi->s_es;
222  unsigned long def_mount_opts;
223 
224  spin_lock(&sbi->s_lock);
225  def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
226 
227  if (sbi->s_sb_block != 1)
228  seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
229  if (test_opt(sb, MINIX_DF))
230  seq_puts(seq, ",minixdf");
231  if (test_opt(sb, GRPID))
232  seq_puts(seq, ",grpid");
233  if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
234  seq_puts(seq, ",nogrpid");
235  if (!uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT2_DEF_RESUID)) ||
236  le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
237  seq_printf(seq, ",resuid=%u",
238  from_kuid_munged(&init_user_ns, sbi->s_resuid));
239  }
240  if (!gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT2_DEF_RESGID)) ||
241  le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
242  seq_printf(seq, ",resgid=%u",
243  from_kgid_munged(&init_user_ns, sbi->s_resgid));
244  }
245  if (test_opt(sb, ERRORS_RO)) {
246  int def_errors = le16_to_cpu(es->s_errors);
247 
248  if (def_errors == EXT2_ERRORS_PANIC ||
249  def_errors == EXT2_ERRORS_CONTINUE) {
250  seq_puts(seq, ",errors=remount-ro");
251  }
252  }
253  if (test_opt(sb, ERRORS_CONT))
254  seq_puts(seq, ",errors=continue");
255  if (test_opt(sb, ERRORS_PANIC))
256  seq_puts(seq, ",errors=panic");
257  if (test_opt(sb, NO_UID32))
258  seq_puts(seq, ",nouid32");
259  if (test_opt(sb, DEBUG))
260  seq_puts(seq, ",debug");
261  if (test_opt(sb, OLDALLOC))
262  seq_puts(seq, ",oldalloc");
263 
264 #ifdef CONFIG_EXT2_FS_XATTR
265  if (test_opt(sb, XATTR_USER))
266  seq_puts(seq, ",user_xattr");
267  if (!test_opt(sb, XATTR_USER) &&
268  (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
269  seq_puts(seq, ",nouser_xattr");
270  }
271 #endif
272 
273 #ifdef CONFIG_EXT2_FS_POSIX_ACL
274  if (test_opt(sb, POSIX_ACL))
275  seq_puts(seq, ",acl");
276  if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
277  seq_puts(seq, ",noacl");
278 #endif
279 
280  if (test_opt(sb, NOBH))
281  seq_puts(seq, ",nobh");
282 
283 #if defined(CONFIG_QUOTA)
284  if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
285  seq_puts(seq, ",usrquota");
286 
287  if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
288  seq_puts(seq, ",grpquota");
289 #endif
290 
291 #if defined(CONFIG_EXT2_FS_XIP)
292  if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
293  seq_puts(seq, ",xip");
294 #endif
295 
296  if (!test_opt(sb, RESERVATION))
297  seq_puts(seq, ",noreservation");
298 
299  spin_unlock(&sbi->s_lock);
300  return 0;
301 }
302 
303 #ifdef CONFIG_QUOTA
304 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
305 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
306 #endif
307 
308 static const struct super_operations ext2_sops = {
309  .alloc_inode = ext2_alloc_inode,
310  .destroy_inode = ext2_destroy_inode,
311  .write_inode = ext2_write_inode,
312  .evict_inode = ext2_evict_inode,
313  .put_super = ext2_put_super,
314  .sync_fs = ext2_sync_fs,
315  .freeze_fs = ext2_freeze,
316  .unfreeze_fs = ext2_unfreeze,
317  .statfs = ext2_statfs,
318  .remount_fs = ext2_remount,
319  .show_options = ext2_show_options,
320 #ifdef CONFIG_QUOTA
321  .quota_read = ext2_quota_read,
322  .quota_write = ext2_quota_write,
323 #endif
324 };
325 
326 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
327  u64 ino, u32 generation)
328 {
329  struct inode *inode;
330 
331  if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
332  return ERR_PTR(-ESTALE);
333  if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
334  return ERR_PTR(-ESTALE);
335 
336  /*
337  * ext2_iget isn't quite right if the inode is currently unallocated!
338  * However ext2_iget currently does appropriate checks to handle stale
339  * inodes so everything is OK.
340  */
341  inode = ext2_iget(sb, ino);
342  if (IS_ERR(inode))
343  return ERR_CAST(inode);
344  if (generation && inode->i_generation != generation) {
345  /* we didn't find the right inode.. */
346  iput(inode);
347  return ERR_PTR(-ESTALE);
348  }
349  return inode;
350 }
351 
352 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
353  int fh_len, int fh_type)
354 {
355  return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
356  ext2_nfs_get_inode);
357 }
358 
359 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
360  int fh_len, int fh_type)
361 {
362  return generic_fh_to_parent(sb, fid, fh_len, fh_type,
363  ext2_nfs_get_inode);
364 }
365 
366 static const struct export_operations ext2_export_ops = {
367  .fh_to_dentry = ext2_fh_to_dentry,
368  .fh_to_parent = ext2_fh_to_parent,
369  .get_parent = ext2_get_parent,
370 };
371 
372 static unsigned long get_sb_block(void **data)
373 {
374  unsigned long sb_block;
375  char *options = (char *) *data;
376 
377  if (!options || strncmp(options, "sb=", 3) != 0)
378  return 1; /* Default location */
379  options += 3;
380  sb_block = simple_strtoul(options, &options, 0);
381  if (*options && *options != ',') {
382  printk("EXT2-fs: Invalid sb specification: %s\n",
383  (char *) *data);
384  return 1;
385  }
386  if (*options == ',')
387  options++;
388  *data = (void *) options;
389  return sb_block;
390 }
391 
392 enum {
393  Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
394  Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
395  Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
396  Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
397  Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
398  Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
399 };
400 
401 static const match_table_t tokens = {
402  {Opt_bsd_df, "bsddf"},
403  {Opt_minix_df, "minixdf"},
404  {Opt_grpid, "grpid"},
405  {Opt_grpid, "bsdgroups"},
406  {Opt_nogrpid, "nogrpid"},
407  {Opt_nogrpid, "sysvgroups"},
408  {Opt_resgid, "resgid=%u"},
409  {Opt_resuid, "resuid=%u"},
410  {Opt_sb, "sb=%u"},
411  {Opt_err_cont, "errors=continue"},
412  {Opt_err_panic, "errors=panic"},
413  {Opt_err_ro, "errors=remount-ro"},
414  {Opt_nouid32, "nouid32"},
415  {Opt_nocheck, "check=none"},
416  {Opt_nocheck, "nocheck"},
417  {Opt_debug, "debug"},
418  {Opt_oldalloc, "oldalloc"},
419  {Opt_orlov, "orlov"},
420  {Opt_nobh, "nobh"},
421  {Opt_user_xattr, "user_xattr"},
422  {Opt_nouser_xattr, "nouser_xattr"},
423  {Opt_acl, "acl"},
424  {Opt_noacl, "noacl"},
425  {Opt_xip, "xip"},
426  {Opt_grpquota, "grpquota"},
427  {Opt_ignore, "noquota"},
428  {Opt_quota, "quota"},
429  {Opt_usrquota, "usrquota"},
430  {Opt_reservation, "reservation"},
431  {Opt_noreservation, "noreservation"},
432  {Opt_err, NULL}
433 };
434 
435 static int parse_options(char *options, struct super_block *sb)
436 {
437  char *p;
438  struct ext2_sb_info *sbi = EXT2_SB(sb);
439  substring_t args[MAX_OPT_ARGS];
440  int option;
441  kuid_t uid;
442  kgid_t gid;
443 
444  if (!options)
445  return 1;
446 
447  while ((p = strsep (&options, ",")) != NULL) {
448  int token;
449  if (!*p)
450  continue;
451 
452  token = match_token(p, tokens, args);
453  switch (token) {
454  case Opt_bsd_df:
455  clear_opt (sbi->s_mount_opt, MINIX_DF);
456  break;
457  case Opt_minix_df:
458  set_opt (sbi->s_mount_opt, MINIX_DF);
459  break;
460  case Opt_grpid:
461  set_opt (sbi->s_mount_opt, GRPID);
462  break;
463  case Opt_nogrpid:
464  clear_opt (sbi->s_mount_opt, GRPID);
465  break;
466  case Opt_resuid:
467  if (match_int(&args[0], &option))
468  return 0;
469  uid = make_kuid(current_user_ns(), option);
470  if (!uid_valid(uid)) {
471  ext2_msg(sb, KERN_ERR, "Invalid uid value %d", option);
472  return 0;
473 
474  }
475  sbi->s_resuid = uid;
476  break;
477  case Opt_resgid:
478  if (match_int(&args[0], &option))
479  return 0;
480  gid = make_kgid(current_user_ns(), option);
481  if (!gid_valid(gid)) {
482  ext2_msg(sb, KERN_ERR, "Invalid gid value %d", option);
483  return 0;
484  }
485  sbi->s_resgid = gid;
486  break;
487  case Opt_sb:
488  /* handled by get_sb_block() instead of here */
489  /* *sb_block = match_int(&args[0]); */
490  break;
491  case Opt_err_panic:
492  clear_opt (sbi->s_mount_opt, ERRORS_CONT);
493  clear_opt (sbi->s_mount_opt, ERRORS_RO);
494  set_opt (sbi->s_mount_opt, ERRORS_PANIC);
495  break;
496  case Opt_err_ro:
497  clear_opt (sbi->s_mount_opt, ERRORS_CONT);
498  clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
499  set_opt (sbi->s_mount_opt, ERRORS_RO);
500  break;
501  case Opt_err_cont:
502  clear_opt (sbi->s_mount_opt, ERRORS_RO);
503  clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
504  set_opt (sbi->s_mount_opt, ERRORS_CONT);
505  break;
506  case Opt_nouid32:
507  set_opt (sbi->s_mount_opt, NO_UID32);
508  break;
509  case Opt_nocheck:
510  clear_opt (sbi->s_mount_opt, CHECK);
511  break;
512  case Opt_debug:
513  set_opt (sbi->s_mount_opt, DEBUG);
514  break;
515  case Opt_oldalloc:
516  set_opt (sbi->s_mount_opt, OLDALLOC);
517  break;
518  case Opt_orlov:
519  clear_opt (sbi->s_mount_opt, OLDALLOC);
520  break;
521  case Opt_nobh:
522  set_opt (sbi->s_mount_opt, NOBH);
523  break;
524 #ifdef CONFIG_EXT2_FS_XATTR
525  case Opt_user_xattr:
526  set_opt (sbi->s_mount_opt, XATTR_USER);
527  break;
528  case Opt_nouser_xattr:
529  clear_opt (sbi->s_mount_opt, XATTR_USER);
530  break;
531 #else
532  case Opt_user_xattr:
533  case Opt_nouser_xattr:
534  ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
535  "not supported");
536  break;
537 #endif
538 #ifdef CONFIG_EXT2_FS_POSIX_ACL
539  case Opt_acl:
540  set_opt(sbi->s_mount_opt, POSIX_ACL);
541  break;
542  case Opt_noacl:
543  clear_opt(sbi->s_mount_opt, POSIX_ACL);
544  break;
545 #else
546  case Opt_acl:
547  case Opt_noacl:
548  ext2_msg(sb, KERN_INFO,
549  "(no)acl options not supported");
550  break;
551 #endif
552  case Opt_xip:
553 #ifdef CONFIG_EXT2_FS_XIP
554  set_opt (sbi->s_mount_opt, XIP);
555 #else
556  ext2_msg(sb, KERN_INFO, "xip option not supported");
557 #endif
558  break;
559 
560 #if defined(CONFIG_QUOTA)
561  case Opt_quota:
562  case Opt_usrquota:
563  set_opt(sbi->s_mount_opt, USRQUOTA);
564  break;
565 
566  case Opt_grpquota:
567  set_opt(sbi->s_mount_opt, GRPQUOTA);
568  break;
569 #else
570  case Opt_quota:
571  case Opt_usrquota:
572  case Opt_grpquota:
573  ext2_msg(sb, KERN_INFO,
574  "quota operations not supported");
575  break;
576 #endif
577 
578  case Opt_reservation:
579  set_opt(sbi->s_mount_opt, RESERVATION);
580  ext2_msg(sb, KERN_INFO, "reservations ON");
581  break;
582  case Opt_noreservation:
583  clear_opt(sbi->s_mount_opt, RESERVATION);
584  ext2_msg(sb, KERN_INFO, "reservations OFF");
585  break;
586  case Opt_ignore:
587  break;
588  default:
589  return 0;
590  }
591  }
592  return 1;
593 }
594 
595 static int ext2_setup_super (struct super_block * sb,
596  struct ext2_super_block * es,
597  int read_only)
598 {
599  int res = 0;
600  struct ext2_sb_info *sbi = EXT2_SB(sb);
601 
602  if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
603  ext2_msg(sb, KERN_ERR,
604  "error: revision level too high, "
605  "forcing read-only mode");
606  res = MS_RDONLY;
607  }
608  if (read_only)
609  return res;
610  if (!(sbi->s_mount_state & EXT2_VALID_FS))
611  ext2_msg(sb, KERN_WARNING,
612  "warning: mounting unchecked fs, "
613  "running e2fsck is recommended");
614  else if ((sbi->s_mount_state & EXT2_ERROR_FS))
615  ext2_msg(sb, KERN_WARNING,
616  "warning: mounting fs with errors, "
617  "running e2fsck is recommended");
618  else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
619  le16_to_cpu(es->s_mnt_count) >=
620  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
621  ext2_msg(sb, KERN_WARNING,
622  "warning: maximal mount count reached, "
623  "running e2fsck is recommended");
624  else if (le32_to_cpu(es->s_checkinterval) &&
625  (le32_to_cpu(es->s_lastcheck) +
626  le32_to_cpu(es->s_checkinterval) <= get_seconds()))
627  ext2_msg(sb, KERN_WARNING,
628  "warning: checktime reached, "
629  "running e2fsck is recommended");
630  if (!le16_to_cpu(es->s_max_mnt_count))
631  es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
632  le16_add_cpu(&es->s_mnt_count, 1);
633  if (test_opt (sb, DEBUG))
634  ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
635  "bpg=%lu, ipg=%lu, mo=%04lx]",
636  EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
637  sbi->s_frag_size,
638  sbi->s_groups_count,
639  EXT2_BLOCKS_PER_GROUP(sb),
640  EXT2_INODES_PER_GROUP(sb),
641  sbi->s_mount_opt);
642  return res;
643 }
644 
645 static int ext2_check_descriptors(struct super_block *sb)
646 {
647  int i;
648  struct ext2_sb_info *sbi = EXT2_SB(sb);
649 
650  ext2_debug ("Checking group descriptors");
651 
652  for (i = 0; i < sbi->s_groups_count; i++) {
653  struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
654  ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
655  ext2_fsblk_t last_block;
656 
657  if (i == sbi->s_groups_count - 1)
658  last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
659  else
660  last_block = first_block +
661  (EXT2_BLOCKS_PER_GROUP(sb) - 1);
662 
663  if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
664  le32_to_cpu(gdp->bg_block_bitmap) > last_block)
665  {
666  ext2_error (sb, "ext2_check_descriptors",
667  "Block bitmap for group %d"
668  " not in group (block %lu)!",
669  i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
670  return 0;
671  }
672  if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
673  le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
674  {
675  ext2_error (sb, "ext2_check_descriptors",
676  "Inode bitmap for group %d"
677  " not in group (block %lu)!",
678  i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
679  return 0;
680  }
681  if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
682  le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
683  last_block)
684  {
685  ext2_error (sb, "ext2_check_descriptors",
686  "Inode table for group %d"
687  " not in group (block %lu)!",
688  i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
689  return 0;
690  }
691  }
692  return 1;
693 }
694 
695 /*
696  * Maximal file size. There is a direct, and {,double-,triple-}indirect
697  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
698  * We need to be 1 filesystem block less than the 2^32 sector limit.
699  */
700 static loff_t ext2_max_size(int bits)
701 {
702  loff_t res = EXT2_NDIR_BLOCKS;
703  int meta_blocks;
704  loff_t upper_limit;
705 
706  /* This is calculated to be the largest file size for a
707  * dense, file such that the total number of
708  * sectors in the file, including data and all indirect blocks,
709  * does not exceed 2^32 -1
710  * __u32 i_blocks representing the total number of
711  * 512 bytes blocks of the file
712  */
713  upper_limit = (1LL << 32) - 1;
714 
715  /* total blocks in file system block size */
716  upper_limit >>= (bits - 9);
717 
718 
719  /* indirect blocks */
720  meta_blocks = 1;
721  /* double indirect blocks */
722  meta_blocks += 1 + (1LL << (bits-2));
723  /* tripple indirect blocks */
724  meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
725 
726  upper_limit -= meta_blocks;
727  upper_limit <<= bits;
728 
729  res += 1LL << (bits-2);
730  res += 1LL << (2*(bits-2));
731  res += 1LL << (3*(bits-2));
732  res <<= bits;
733  if (res > upper_limit)
734  res = upper_limit;
735 
736  if (res > MAX_LFS_FILESIZE)
737  res = MAX_LFS_FILESIZE;
738 
739  return res;
740 }
741 
742 static unsigned long descriptor_loc(struct super_block *sb,
743  unsigned long logic_sb_block,
744  int nr)
745 {
746  struct ext2_sb_info *sbi = EXT2_SB(sb);
747  unsigned long bg, first_meta_bg;
748  int has_super = 0;
749 
750  first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
751 
752  if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
753  nr < first_meta_bg)
754  return (logic_sb_block + nr + 1);
755  bg = sbi->s_desc_per_block * nr;
756  if (ext2_bg_has_super(sb, bg))
757  has_super = 1;
758 
759  return ext2_group_first_block_no(sb, bg) + has_super;
760 }
761 
762 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
763 {
764  struct buffer_head * bh;
765  struct ext2_sb_info * sbi;
766  struct ext2_super_block * es;
767  struct inode *root;
768  unsigned long block;
769  unsigned long sb_block = get_sb_block(&data);
770  unsigned long logic_sb_block;
771  unsigned long offset = 0;
772  unsigned long def_mount_opts;
773  long ret = -EINVAL;
774  int blocksize = BLOCK_SIZE;
775  int db_count;
776  int i, j;
777  __le32 features;
778  int err;
779 
780  err = -ENOMEM;
781  sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
782  if (!sbi)
783  goto failed;
784 
785  sbi->s_blockgroup_lock =
786  kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
787  if (!sbi->s_blockgroup_lock) {
788  kfree(sbi);
789  goto failed;
790  }
791  sb->s_fs_info = sbi;
792  sbi->s_sb_block = sb_block;
793 
794  spin_lock_init(&sbi->s_lock);
795 
796  /*
797  * See what the current blocksize for the device is, and
798  * use that as the blocksize. Otherwise (or if the blocksize
799  * is smaller than the default) use the default.
800  * This is important for devices that have a hardware
801  * sectorsize that is larger than the default.
802  */
803  blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
804  if (!blocksize) {
805  ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
806  goto failed_sbi;
807  }
808 
809  /*
810  * If the superblock doesn't start on a hardware sector boundary,
811  * calculate the offset.
812  */
813  if (blocksize != BLOCK_SIZE) {
814  logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
815  offset = (sb_block*BLOCK_SIZE) % blocksize;
816  } else {
817  logic_sb_block = sb_block;
818  }
819 
820  if (!(bh = sb_bread(sb, logic_sb_block))) {
821  ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
822  goto failed_sbi;
823  }
824  /*
825  * Note: s_es must be initialized as soon as possible because
826  * some ext2 macro-instructions depend on its value
827  */
828  es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
829  sbi->s_es = es;
830  sb->s_magic = le16_to_cpu(es->s_magic);
831 
832  if (sb->s_magic != EXT2_SUPER_MAGIC)
833  goto cantfind_ext2;
834 
835  /* Set defaults before we parse the mount options */
836  def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
837  if (def_mount_opts & EXT2_DEFM_DEBUG)
838  set_opt(sbi->s_mount_opt, DEBUG);
839  if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
840  set_opt(sbi->s_mount_opt, GRPID);
841  if (def_mount_opts & EXT2_DEFM_UID16)
842  set_opt(sbi->s_mount_opt, NO_UID32);
843 #ifdef CONFIG_EXT2_FS_XATTR
844  if (def_mount_opts & EXT2_DEFM_XATTR_USER)
845  set_opt(sbi->s_mount_opt, XATTR_USER);
846 #endif
847 #ifdef CONFIG_EXT2_FS_POSIX_ACL
848  if (def_mount_opts & EXT2_DEFM_ACL)
849  set_opt(sbi->s_mount_opt, POSIX_ACL);
850 #endif
851 
852  if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
853  set_opt(sbi->s_mount_opt, ERRORS_PANIC);
854  else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
855  set_opt(sbi->s_mount_opt, ERRORS_CONT);
856  else
857  set_opt(sbi->s_mount_opt, ERRORS_RO);
858 
859  sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
860  sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
861 
862  set_opt(sbi->s_mount_opt, RESERVATION);
863 
864  if (!parse_options((char *) data, sb))
865  goto failed_mount;
866 
867  sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
868  ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
869  MS_POSIXACL : 0);
870 
871  ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
872  EXT2_MOUNT_XIP if not */
873 
874  if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
875  (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
876  EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
877  EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
878  ext2_msg(sb, KERN_WARNING,
879  "warning: feature flags set on rev 0 fs, "
880  "running e2fsck is recommended");
881  /*
882  * Check feature flags regardless of the revision level, since we
883  * previously didn't change the revision level when setting the flags,
884  * so there is a chance incompat flags are set on a rev 0 filesystem.
885  */
886  features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
887  if (features) {
888  ext2_msg(sb, KERN_ERR, "error: couldn't mount because of "
889  "unsupported optional features (%x)",
890  le32_to_cpu(features));
891  goto failed_mount;
892  }
893  if (!(sb->s_flags & MS_RDONLY) &&
894  (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
895  ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
896  "unsupported optional features (%x)",
897  le32_to_cpu(features));
898  goto failed_mount;
899  }
900 
901  blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
902 
903  if (ext2_use_xip(sb) && blocksize != PAGE_SIZE) {
904  if (!silent)
905  ext2_msg(sb, KERN_ERR,
906  "error: unsupported blocksize for xip");
907  goto failed_mount;
908  }
909 
910  /* If the blocksize doesn't match, re-read the thing.. */
911  if (sb->s_blocksize != blocksize) {
912  brelse(bh);
913 
914  if (!sb_set_blocksize(sb, blocksize)) {
915  ext2_msg(sb, KERN_ERR,
916  "error: bad blocksize %d", blocksize);
917  goto failed_sbi;
918  }
919 
920  logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
921  offset = (sb_block*BLOCK_SIZE) % blocksize;
922  bh = sb_bread(sb, logic_sb_block);
923  if(!bh) {
924  ext2_msg(sb, KERN_ERR, "error: couldn't read"
925  "superblock on 2nd try");
926  goto failed_sbi;
927  }
928  es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
929  sbi->s_es = es;
930  if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
931  ext2_msg(sb, KERN_ERR, "error: magic mismatch");
932  goto failed_mount;
933  }
934  }
935 
936  sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
937  sb->s_max_links = EXT2_LINK_MAX;
938 
939  if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
940  sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
941  sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
942  } else {
943  sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
944  sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
945  if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
946  !is_power_of_2(sbi->s_inode_size) ||
947  (sbi->s_inode_size > blocksize)) {
948  ext2_msg(sb, KERN_ERR,
949  "error: unsupported inode size: %d",
950  sbi->s_inode_size);
951  goto failed_mount;
952  }
953  }
954 
955  sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
956  le32_to_cpu(es->s_log_frag_size);
957  if (sbi->s_frag_size == 0)
958  goto cantfind_ext2;
959  sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
960 
961  sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
962  sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
963  sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
964 
965  if (EXT2_INODE_SIZE(sb) == 0)
966  goto cantfind_ext2;
967  sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
968  if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
969  goto cantfind_ext2;
970  sbi->s_itb_per_group = sbi->s_inodes_per_group /
971  sbi->s_inodes_per_block;
972  sbi->s_desc_per_block = sb->s_blocksize /
973  sizeof (struct ext2_group_desc);
974  sbi->s_sbh = bh;
975  sbi->s_mount_state = le16_to_cpu(es->s_state);
976  sbi->s_addr_per_block_bits =
977  ilog2 (EXT2_ADDR_PER_BLOCK(sb));
978  sbi->s_desc_per_block_bits =
979  ilog2 (EXT2_DESC_PER_BLOCK(sb));
980 
981  if (sb->s_magic != EXT2_SUPER_MAGIC)
982  goto cantfind_ext2;
983 
984  if (sb->s_blocksize != bh->b_size) {
985  if (!silent)
986  ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
987  goto failed_mount;
988  }
989 
990  if (sb->s_blocksize != sbi->s_frag_size) {
991  ext2_msg(sb, KERN_ERR,
992  "error: fragsize %lu != blocksize %lu"
993  "(not supported yet)",
994  sbi->s_frag_size, sb->s_blocksize);
995  goto failed_mount;
996  }
997 
998  if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
999  ext2_msg(sb, KERN_ERR,
1000  "error: #blocks per group too big: %lu",
1001  sbi->s_blocks_per_group);
1002  goto failed_mount;
1003  }
1004  if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
1005  ext2_msg(sb, KERN_ERR,
1006  "error: #fragments per group too big: %lu",
1007  sbi->s_frags_per_group);
1008  goto failed_mount;
1009  }
1010  if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
1011  ext2_msg(sb, KERN_ERR,
1012  "error: #inodes per group too big: %lu",
1013  sbi->s_inodes_per_group);
1014  goto failed_mount;
1015  }
1016 
1017  if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
1018  goto cantfind_ext2;
1019  sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
1020  le32_to_cpu(es->s_first_data_block) - 1)
1021  / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
1022  db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
1023  EXT2_DESC_PER_BLOCK(sb);
1024  sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
1025  if (sbi->s_group_desc == NULL) {
1026  ext2_msg(sb, KERN_ERR, "error: not enough memory");
1027  goto failed_mount;
1028  }
1029  bgl_lock_init(sbi->s_blockgroup_lock);
1030  sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1031  if (!sbi->s_debts) {
1032  ext2_msg(sb, KERN_ERR, "error: not enough memory");
1033  goto failed_mount_group_desc;
1034  }
1035  for (i = 0; i < db_count; i++) {
1036  block = descriptor_loc(sb, logic_sb_block, i);
1037  sbi->s_group_desc[i] = sb_bread(sb, block);
1038  if (!sbi->s_group_desc[i]) {
1039  for (j = 0; j < i; j++)
1040  brelse (sbi->s_group_desc[j]);
1041  ext2_msg(sb, KERN_ERR,
1042  "error: unable to read group descriptors");
1043  goto failed_mount_group_desc;
1044  }
1045  }
1046  if (!ext2_check_descriptors (sb)) {
1047  ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1048  goto failed_mount2;
1049  }
1050  sbi->s_gdb_count = db_count;
1051  get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1052  spin_lock_init(&sbi->s_next_gen_lock);
1053 
1054  /* per fileystem reservation list head & lock */
1055  spin_lock_init(&sbi->s_rsv_window_lock);
1056  sbi->s_rsv_window_root = RB_ROOT;
1057  /*
1058  * Add a single, static dummy reservation to the start of the
1059  * reservation window list --- it gives us a placeholder for
1060  * append-at-start-of-list which makes the allocation logic
1061  * _much_ simpler.
1062  */
1063  sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1064  sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1065  sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1066  sbi->s_rsv_window_head.rsv_goal_size = 0;
1067  ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1068 
1069  err = percpu_counter_init(&sbi->s_freeblocks_counter,
1070  ext2_count_free_blocks(sb));
1071  if (!err) {
1072  err = percpu_counter_init(&sbi->s_freeinodes_counter,
1073  ext2_count_free_inodes(sb));
1074  }
1075  if (!err) {
1076  err = percpu_counter_init(&sbi->s_dirs_counter,
1077  ext2_count_dirs(sb));
1078  }
1079  if (err) {
1080  ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1081  goto failed_mount3;
1082  }
1083  /*
1084  * set up enough so that it can read an inode
1085  */
1086  sb->s_op = &ext2_sops;
1087  sb->s_export_op = &ext2_export_ops;
1088  sb->s_xattr = ext2_xattr_handlers;
1089 
1090 #ifdef CONFIG_QUOTA
1091  sb->dq_op = &dquot_operations;
1092  sb->s_qcop = &dquot_quotactl_ops;
1093 #endif
1094 
1095  root = ext2_iget(sb, EXT2_ROOT_INO);
1096  if (IS_ERR(root)) {
1097  ret = PTR_ERR(root);
1098  goto failed_mount3;
1099  }
1100  if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1101  iput(root);
1102  ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1103  goto failed_mount3;
1104  }
1105 
1106  sb->s_root = d_make_root(root);
1107  if (!sb->s_root) {
1108  ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1109  ret = -ENOMEM;
1110  goto failed_mount3;
1111  }
1112  if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1113  ext2_msg(sb, KERN_WARNING,
1114  "warning: mounting ext3 filesystem as ext2");
1115  if (ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY))
1116  sb->s_flags |= MS_RDONLY;
1117  ext2_write_super(sb);
1118  return 0;
1119 
1120 cantfind_ext2:
1121  if (!silent)
1122  ext2_msg(sb, KERN_ERR,
1123  "error: can't find an ext2 filesystem on dev %s.",
1124  sb->s_id);
1125  goto failed_mount;
1126 failed_mount3:
1127  percpu_counter_destroy(&sbi->s_freeblocks_counter);
1128  percpu_counter_destroy(&sbi->s_freeinodes_counter);
1129  percpu_counter_destroy(&sbi->s_dirs_counter);
1130 failed_mount2:
1131  for (i = 0; i < db_count; i++)
1132  brelse(sbi->s_group_desc[i]);
1133 failed_mount_group_desc:
1134  kfree(sbi->s_group_desc);
1135  kfree(sbi->s_debts);
1136 failed_mount:
1137  brelse(bh);
1138 failed_sbi:
1139  sb->s_fs_info = NULL;
1140  kfree(sbi->s_blockgroup_lock);
1141  kfree(sbi);
1142 failed:
1143  return ret;
1144 }
1145 
1146 static void ext2_clear_super_error(struct super_block *sb)
1147 {
1148  struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1149 
1150  if (buffer_write_io_error(sbh)) {
1151  /*
1152  * Oh, dear. A previous attempt to write the
1153  * superblock failed. This could happen because the
1154  * USB device was yanked out. Or it could happen to
1155  * be a transient write error and maybe the block will
1156  * be remapped. Nothing we can do but to retry the
1157  * write and hope for the best.
1158  */
1159  ext2_msg(sb, KERN_ERR,
1160  "previous I/O error to superblock detected\n");
1161  clear_buffer_write_io_error(sbh);
1162  set_buffer_uptodate(sbh);
1163  }
1164 }
1165 
1166 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
1167  int wait)
1168 {
1169  ext2_clear_super_error(sb);
1170  spin_lock(&EXT2_SB(sb)->s_lock);
1171  es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1172  es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1173  es->s_wtime = cpu_to_le32(get_seconds());
1174  /* unlock before we do IO */
1175  spin_unlock(&EXT2_SB(sb)->s_lock);
1176  mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1177  if (wait)
1178  sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1179 }
1180 
1181 /*
1182  * In the second extended file system, it is not necessary to
1183  * write the super block since we use a mapping of the
1184  * disk super block in a buffer.
1185  *
1186  * However, this function is still used to set the fs valid
1187  * flags to 0. We need to set this flag to 0 since the fs
1188  * may have been checked while mounted and e2fsck may have
1189  * set s_state to EXT2_VALID_FS after some corrections.
1190  */
1191 static int ext2_sync_fs(struct super_block *sb, int wait)
1192 {
1193  struct ext2_sb_info *sbi = EXT2_SB(sb);
1194  struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1195 
1196  /*
1197  * Write quota structures to quota file, sync_blockdev() will write
1198  * them to disk later
1199  */
1200  dquot_writeback_dquots(sb, -1);
1201 
1202  spin_lock(&sbi->s_lock);
1203  if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1204  ext2_debug("setting valid to 0\n");
1205  es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1206  }
1207  spin_unlock(&sbi->s_lock);
1208  ext2_sync_super(sb, es, wait);
1209  return 0;
1210 }
1211 
1212 static int ext2_freeze(struct super_block *sb)
1213 {
1214  struct ext2_sb_info *sbi = EXT2_SB(sb);
1215 
1216  /*
1217  * Open but unlinked files present? Keep EXT2_VALID_FS flag cleared
1218  * because we have unattached inodes and thus filesystem is not fully
1219  * consistent.
1220  */
1221  if (atomic_long_read(&sb->s_remove_count)) {
1222  ext2_sync_fs(sb, 1);
1223  return 0;
1224  }
1225  /* Set EXT2_FS_VALID flag */
1226  spin_lock(&sbi->s_lock);
1227  sbi->s_es->s_state = cpu_to_le16(sbi->s_mount_state);
1228  spin_unlock(&sbi->s_lock);
1229  ext2_sync_super(sb, sbi->s_es, 1);
1230 
1231  return 0;
1232 }
1233 
1234 static int ext2_unfreeze(struct super_block *sb)
1235 {
1236  /* Just write sb to clear EXT2_VALID_FS flag */
1237  ext2_write_super(sb);
1238 
1239  return 0;
1240 }
1241 
1242 void ext2_write_super(struct super_block *sb)
1243 {
1244  if (!(sb->s_flags & MS_RDONLY))
1245  ext2_sync_fs(sb, 1);
1246 }
1247 
1248 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1249 {
1250  struct ext2_sb_info * sbi = EXT2_SB(sb);
1251  struct ext2_super_block * es;
1252  unsigned long old_mount_opt = sbi->s_mount_opt;
1253  struct ext2_mount_options old_opts;
1254  unsigned long old_sb_flags;
1255  int err;
1256 
1257  spin_lock(&sbi->s_lock);
1258 
1259  /* Store the old options */
1260  old_sb_flags = sb->s_flags;
1261  old_opts.s_mount_opt = sbi->s_mount_opt;
1262  old_opts.s_resuid = sbi->s_resuid;
1263  old_opts.s_resgid = sbi->s_resgid;
1264 
1265  /*
1266  * Allow the "check" option to be passed as a remount option.
1267  */
1268  if (!parse_options(data, sb)) {
1269  err = -EINVAL;
1270  goto restore_opts;
1271  }
1272 
1273  sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1274  ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1275 
1276  ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1277  EXT2_MOUNT_XIP if not */
1278 
1279  if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1280  ext2_msg(sb, KERN_WARNING,
1281  "warning: unsupported blocksize for xip");
1282  err = -EINVAL;
1283  goto restore_opts;
1284  }
1285 
1286  es = sbi->s_es;
1287  if ((sbi->s_mount_opt ^ old_mount_opt) & EXT2_MOUNT_XIP) {
1288  ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1289  "xip flag with busy inodes while remounting");
1290  sbi->s_mount_opt &= ~EXT2_MOUNT_XIP;
1291  sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;
1292  }
1293  if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
1294  spin_unlock(&sbi->s_lock);
1295  return 0;
1296  }
1297  if (*flags & MS_RDONLY) {
1298  if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1299  !(sbi->s_mount_state & EXT2_VALID_FS)) {
1300  spin_unlock(&sbi->s_lock);
1301  return 0;
1302  }
1303 
1304  /*
1305  * OK, we are remounting a valid rw partition rdonly, so set
1306  * the rdonly flag and then mark the partition as valid again.
1307  */
1308  es->s_state = cpu_to_le16(sbi->s_mount_state);
1309  es->s_mtime = cpu_to_le32(get_seconds());
1310  spin_unlock(&sbi->s_lock);
1311 
1312  err = dquot_suspend(sb, -1);
1313  if (err < 0) {
1314  spin_lock(&sbi->s_lock);
1315  goto restore_opts;
1316  }
1317 
1318  ext2_sync_super(sb, es, 1);
1319  } else {
1320  __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1321  ~EXT2_FEATURE_RO_COMPAT_SUPP);
1322  if (ret) {
1323  ext2_msg(sb, KERN_WARNING,
1324  "warning: couldn't remount RDWR because of "
1325  "unsupported optional features (%x).",
1326  le32_to_cpu(ret));
1327  err = -EROFS;
1328  goto restore_opts;
1329  }
1330  /*
1331  * Mounting a RDONLY partition read-write, so reread and
1332  * store the current valid flag. (It may have been changed
1333  * by e2fsck since we originally mounted the partition.)
1334  */
1335  sbi->s_mount_state = le16_to_cpu(es->s_state);
1336  if (!ext2_setup_super (sb, es, 0))
1337  sb->s_flags &= ~MS_RDONLY;
1338  spin_unlock(&sbi->s_lock);
1339 
1340  ext2_write_super(sb);
1341 
1342  dquot_resume(sb, -1);
1343  }
1344 
1345  return 0;
1346 restore_opts:
1347  sbi->s_mount_opt = old_opts.s_mount_opt;
1348  sbi->s_resuid = old_opts.s_resuid;
1349  sbi->s_resgid = old_opts.s_resgid;
1350  sb->s_flags = old_sb_flags;
1351  spin_unlock(&sbi->s_lock);
1352  return err;
1353 }
1354 
1355 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1356 {
1357  struct super_block *sb = dentry->d_sb;
1358  struct ext2_sb_info *sbi = EXT2_SB(sb);
1359  struct ext2_super_block *es = sbi->s_es;
1360  u64 fsid;
1361 
1362  spin_lock(&sbi->s_lock);
1363 
1364  if (test_opt (sb, MINIX_DF))
1365  sbi->s_overhead_last = 0;
1366  else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1367  unsigned long i, overhead = 0;
1368  smp_rmb();
1369 
1370  /*
1371  * Compute the overhead (FS structures). This is constant
1372  * for a given filesystem unless the number of block groups
1373  * changes so we cache the previous value until it does.
1374  */
1375 
1376  /*
1377  * All of the blocks before first_data_block are
1378  * overhead
1379  */
1380  overhead = le32_to_cpu(es->s_first_data_block);
1381 
1382  /*
1383  * Add the overhead attributed to the superblock and
1384  * block group descriptors. If the sparse superblocks
1385  * feature is turned on, then not all groups have this.
1386  */
1387  for (i = 0; i < sbi->s_groups_count; i++)
1388  overhead += ext2_bg_has_super(sb, i) +
1389  ext2_bg_num_gdb(sb, i);
1390 
1391  /*
1392  * Every block group has an inode bitmap, a block
1393  * bitmap, and an inode table.
1394  */
1395  overhead += (sbi->s_groups_count *
1396  (2 + sbi->s_itb_per_group));
1397  sbi->s_overhead_last = overhead;
1398  smp_wmb();
1399  sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1400  }
1401 
1402  buf->f_type = EXT2_SUPER_MAGIC;
1403  buf->f_bsize = sb->s_blocksize;
1404  buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1405  buf->f_bfree = ext2_count_free_blocks(sb);
1406  es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1407  buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1408  if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1409  buf->f_bavail = 0;
1410  buf->f_files = le32_to_cpu(es->s_inodes_count);
1411  buf->f_ffree = ext2_count_free_inodes(sb);
1412  es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1413  buf->f_namelen = EXT2_NAME_LEN;
1414  fsid = le64_to_cpup((void *)es->s_uuid) ^
1415  le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1416  buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1417  buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1418  spin_unlock(&sbi->s_lock);
1419  return 0;
1420 }
1421 
1422 static struct dentry *ext2_mount(struct file_system_type *fs_type,
1423  int flags, const char *dev_name, void *data)
1424 {
1425  return mount_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1426 }
1427 
1428 #ifdef CONFIG_QUOTA
1429 
1430 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1431  * acquiring the locks... As quota files are never truncated and quota code
1432  * itself serializes the operations (and no one else should touch the files)
1433  * we don't have to be afraid of races */
1434 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1435  size_t len, loff_t off)
1436 {
1437  struct inode *inode = sb_dqopt(sb)->files[type];
1438  sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1439  int err = 0;
1440  int offset = off & (sb->s_blocksize - 1);
1441  int tocopy;
1442  size_t toread;
1443  struct buffer_head tmp_bh;
1444  struct buffer_head *bh;
1445  loff_t i_size = i_size_read(inode);
1446 
1447  if (off > i_size)
1448  return 0;
1449  if (off+len > i_size)
1450  len = i_size-off;
1451  toread = len;
1452  while (toread > 0) {
1453  tocopy = sb->s_blocksize - offset < toread ?
1454  sb->s_blocksize - offset : toread;
1455 
1456  tmp_bh.b_state = 0;
1457  tmp_bh.b_size = sb->s_blocksize;
1458  err = ext2_get_block(inode, blk, &tmp_bh, 0);
1459  if (err < 0)
1460  return err;
1461  if (!buffer_mapped(&tmp_bh)) /* A hole? */
1462  memset(data, 0, tocopy);
1463  else {
1464  bh = sb_bread(sb, tmp_bh.b_blocknr);
1465  if (!bh)
1466  return -EIO;
1467  memcpy(data, bh->b_data+offset, tocopy);
1468  brelse(bh);
1469  }
1470  offset = 0;
1471  toread -= tocopy;
1472  data += tocopy;
1473  blk++;
1474  }
1475  return len;
1476 }
1477 
1478 /* Write to quotafile */
1479 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1480  const char *data, size_t len, loff_t off)
1481 {
1482  struct inode *inode = sb_dqopt(sb)->files[type];
1483  sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1484  int err = 0;
1485  int offset = off & (sb->s_blocksize - 1);
1486  int tocopy;
1487  size_t towrite = len;
1488  struct buffer_head tmp_bh;
1489  struct buffer_head *bh;
1490 
1491  while (towrite > 0) {
1492  tocopy = sb->s_blocksize - offset < towrite ?
1493  sb->s_blocksize - offset : towrite;
1494 
1495  tmp_bh.b_state = 0;
1496  err = ext2_get_block(inode, blk, &tmp_bh, 1);
1497  if (err < 0)
1498  goto out;
1499  if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1500  bh = sb_bread(sb, tmp_bh.b_blocknr);
1501  else
1502  bh = sb_getblk(sb, tmp_bh.b_blocknr);
1503  if (!bh) {
1504  err = -EIO;
1505  goto out;
1506  }
1507  lock_buffer(bh);
1508  memcpy(bh->b_data+offset, data, tocopy);
1509  flush_dcache_page(bh->b_page);
1510  set_buffer_uptodate(bh);
1511  mark_buffer_dirty(bh);
1512  unlock_buffer(bh);
1513  brelse(bh);
1514  offset = 0;
1515  towrite -= tocopy;
1516  data += tocopy;
1517  blk++;
1518  }
1519 out:
1520  if (len == towrite)
1521  return err;
1522  if (inode->i_size < off+len-towrite)
1523  i_size_write(inode, off+len-towrite);
1524  inode->i_version++;
1525  inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1526  mark_inode_dirty(inode);
1527  return len - towrite;
1528 }
1529 
1530 #endif
1531 
1532 static struct file_system_type ext2_fs_type = {
1533  .owner = THIS_MODULE,
1534  .name = "ext2",
1535  .mount = ext2_mount,
1536  .kill_sb = kill_block_super,
1537  .fs_flags = FS_REQUIRES_DEV,
1538 };
1539 
1540 static int __init init_ext2_fs(void)
1541 {
1542  int err = init_ext2_xattr();
1543  if (err)
1544  return err;
1545  err = init_inodecache();
1546  if (err)
1547  goto out1;
1548  err = register_filesystem(&ext2_fs_type);
1549  if (err)
1550  goto out;
1551  return 0;
1552 out:
1553  destroy_inodecache();
1554 out1:
1555  exit_ext2_xattr();
1556  return err;
1557 }
1558 
1559 static void __exit exit_ext2_fs(void)
1560 {
1561  unregister_filesystem(&ext2_fs_type);
1562  destroy_inodecache();
1563  exit_ext2_xattr();
1564 }
1565 
1566 MODULE_AUTHOR("Remy Card and others");
1567 MODULE_DESCRIPTION("Second Extended Filesystem");
1568 MODULE_LICENSE("GPL");
1569 module_init(init_ext2_fs)
1570 module_exit(exit_ext2_fs)
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