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Linux/fs/ext2/super.c

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  1 // SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  *  linux/fs/ext2/super.c
  4  *
  5  * Copyright (C) 1992, 1993, 1994, 1995
  6  * Remy Card (card@masi.ibp.fr)
  7  * Laboratoire MASI - Institut Blaise Pascal
  8  * Universite Pierre et Marie Curie (Paris VI)
  9  *
 10  *  from
 11  *
 12  *  linux/fs/minix/inode.c
 13  *
 14  *  Copyright (C) 1991, 1992  Linus Torvalds
 15  *
 16  *  Big-endian to little-endian byte-swapping/bitmaps by
 17  *        David S. Miller (davem@caip.rutgers.edu), 1995
 18  */
 19 
 20 #include <linux/module.h>
 21 #include <linux/string.h>
 22 #include <linux/fs.h>
 23 #include <linux/slab.h>
 24 #include <linux/init.h>
 25 #include <linux/blkdev.h>
 26 #include <linux/parser.h>
 27 #include <linux/random.h>
 28 #include <linux/buffer_head.h>
 29 #include <linux/exportfs.h>
 30 #include <linux/vfs.h>
 31 #include <linux/seq_file.h>
 32 #include <linux/mount.h>
 33 #include <linux/log2.h>
 34 #include <linux/quotaops.h>
 35 #include <linux/uaccess.h>
 36 #include <linux/dax.h>
 37 #include <linux/iversion.h>
 38 #include "ext2.h"
 39 #include "xattr.h"
 40 #include "acl.h"
 41 
 42 static void ext2_write_super(struct super_block *sb);
 43 static int ext2_remount (struct super_block * sb, int * flags, char * data);
 44 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
 45 static int ext2_sync_fs(struct super_block *sb, int wait);
 46 static int ext2_freeze(struct super_block *sb);
 47 static int ext2_unfreeze(struct super_block *sb);
 48 
 49 void ext2_error(struct super_block *sb, const char *function,
 50                 const char *fmt, ...)
 51 {
 52         struct va_format vaf;
 53         va_list args;
 54         struct ext2_sb_info *sbi = EXT2_SB(sb);
 55         struct ext2_super_block *es = sbi->s_es;
 56 
 57         if (!sb_rdonly(sb)) {
 58                 spin_lock(&sbi->s_lock);
 59                 sbi->s_mount_state |= EXT2_ERROR_FS;
 60                 es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
 61                 spin_unlock(&sbi->s_lock);
 62                 ext2_sync_super(sb, es, 1);
 63         }
 64 
 65         va_start(args, fmt);
 66 
 67         vaf.fmt = fmt;
 68         vaf.va = &args;
 69 
 70         printk(KERN_CRIT "EXT2-fs (%s): error: %s: %pV\n",
 71                sb->s_id, function, &vaf);
 72 
 73         va_end(args);
 74 
 75         if (test_opt(sb, ERRORS_PANIC))
 76                 panic("EXT2-fs: panic from previous error\n");
 77         if (!sb_rdonly(sb) && test_opt(sb, ERRORS_RO)) {
 78                 ext2_msg(sb, KERN_CRIT,
 79                              "error: remounting filesystem read-only");
 80                 sb->s_flags |= SB_RDONLY;
 81         }
 82 }
 83 
 84 void ext2_msg(struct super_block *sb, const char *prefix,
 85                 const char *fmt, ...)
 86 {
 87         struct va_format vaf;
 88         va_list args;
 89 
 90         va_start(args, fmt);
 91 
 92         vaf.fmt = fmt;
 93         vaf.va = &args;
 94 
 95         printk("%sEXT2-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
 96 
 97         va_end(args);
 98 }
 99 
100 /*
101  * This must be called with sbi->s_lock held.
102  */
103 void ext2_update_dynamic_rev(struct super_block *sb)
104 {
105         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
106 
107         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
108                 return;
109 
110         ext2_msg(sb, KERN_WARNING,
111                      "warning: updating to rev %d because of "
112                      "new feature flag, running e2fsck is recommended",
113                      EXT2_DYNAMIC_REV);
114 
115         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
116         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
117         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
118         /* leave es->s_feature_*compat flags alone */
119         /* es->s_uuid will be set by e2fsck if empty */
120 
121         /*
122          * The rest of the superblock fields should be zero, and if not it
123          * means they are likely already in use, so leave them alone.  We
124          * can leave it up to e2fsck to clean up any inconsistencies there.
125          */
126 }
127 
128 #ifdef CONFIG_QUOTA
129 static int ext2_quota_off(struct super_block *sb, int type);
130 
131 static void ext2_quota_off_umount(struct super_block *sb)
132 {
133         int type;
134 
135         for (type = 0; type < MAXQUOTAS; type++)
136                 ext2_quota_off(sb, type);
137 }
138 #else
139 static inline void ext2_quota_off_umount(struct super_block *sb)
140 {
141 }
142 #endif
143 
144 static void ext2_put_super (struct super_block * sb)
145 {
146         int db_count;
147         int i;
148         struct ext2_sb_info *sbi = EXT2_SB(sb);
149 
150         ext2_quota_off_umount(sb);
151 
152         ext2_xattr_destroy_cache(sbi->s_ea_block_cache);
153         sbi->s_ea_block_cache = NULL;
154 
155         if (!sb_rdonly(sb)) {
156                 struct ext2_super_block *es = sbi->s_es;
157 
158                 spin_lock(&sbi->s_lock);
159                 es->s_state = cpu_to_le16(sbi->s_mount_state);
160                 spin_unlock(&sbi->s_lock);
161                 ext2_sync_super(sb, es, 1);
162         }
163         db_count = sbi->s_gdb_count;
164         for (i = 0; i < db_count; i++)
165                 if (sbi->s_group_desc[i])
166                         brelse (sbi->s_group_desc[i]);
167         kfree(sbi->s_group_desc);
168         kfree(sbi->s_debts);
169         percpu_counter_destroy(&sbi->s_freeblocks_counter);
170         percpu_counter_destroy(&sbi->s_freeinodes_counter);
171         percpu_counter_destroy(&sbi->s_dirs_counter);
172         brelse (sbi->s_sbh);
173         sb->s_fs_info = NULL;
174         kfree(sbi->s_blockgroup_lock);
175         fs_put_dax(sbi->s_daxdev);
176         kfree(sbi);
177 }
178 
179 static struct kmem_cache * ext2_inode_cachep;
180 
181 static struct inode *ext2_alloc_inode(struct super_block *sb)
182 {
183         struct ext2_inode_info *ei;
184         ei = kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
185         if (!ei)
186                 return NULL;
187         ei->i_block_alloc_info = NULL;
188         inode_set_iversion(&ei->vfs_inode, 1);
189 #ifdef CONFIG_QUOTA
190         memset(&ei->i_dquot, 0, sizeof(ei->i_dquot));
191 #endif
192 
193         return &ei->vfs_inode;
194 }
195 
196 static void ext2_free_in_core_inode(struct inode *inode)
197 {
198         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
199 }
200 
201 static void init_once(void *foo)
202 {
203         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
204 
205         rwlock_init(&ei->i_meta_lock);
206 #ifdef CONFIG_EXT2_FS_XATTR
207         init_rwsem(&ei->xattr_sem);
208 #endif
209         mutex_init(&ei->truncate_mutex);
210 #ifdef CONFIG_FS_DAX
211         init_rwsem(&ei->dax_sem);
212 #endif
213         inode_init_once(&ei->vfs_inode);
214 }
215 
216 static int __init init_inodecache(void)
217 {
218         ext2_inode_cachep = kmem_cache_create_usercopy("ext2_inode_cache",
219                                 sizeof(struct ext2_inode_info), 0,
220                                 (SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
221                                         SLAB_ACCOUNT),
222                                 offsetof(struct ext2_inode_info, i_data),
223                                 sizeof_field(struct ext2_inode_info, i_data),
224                                 init_once);
225         if (ext2_inode_cachep == NULL)
226                 return -ENOMEM;
227         return 0;
228 }
229 
230 static void destroy_inodecache(void)
231 {
232         /*
233          * Make sure all delayed rcu free inodes are flushed before we
234          * destroy cache.
235          */
236         rcu_barrier();
237         kmem_cache_destroy(ext2_inode_cachep);
238 }
239 
240 static int ext2_show_options(struct seq_file *seq, struct dentry *root)
241 {
242         struct super_block *sb = root->d_sb;
243         struct ext2_sb_info *sbi = EXT2_SB(sb);
244         struct ext2_super_block *es = sbi->s_es;
245         unsigned long def_mount_opts;
246 
247         spin_lock(&sbi->s_lock);
248         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
249 
250         if (sbi->s_sb_block != 1)
251                 seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
252         if (test_opt(sb, MINIX_DF))
253                 seq_puts(seq, ",minixdf");
254         if (test_opt(sb, GRPID))
255                 seq_puts(seq, ",grpid");
256         if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
257                 seq_puts(seq, ",nogrpid");
258         if (!uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT2_DEF_RESUID)) ||
259             le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
260                 seq_printf(seq, ",resuid=%u",
261                                 from_kuid_munged(&init_user_ns, sbi->s_resuid));
262         }
263         if (!gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT2_DEF_RESGID)) ||
264             le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
265                 seq_printf(seq, ",resgid=%u",
266                                 from_kgid_munged(&init_user_ns, sbi->s_resgid));
267         }
268         if (test_opt(sb, ERRORS_RO)) {
269                 int def_errors = le16_to_cpu(es->s_errors);
270 
271                 if (def_errors == EXT2_ERRORS_PANIC ||
272                     def_errors == EXT2_ERRORS_CONTINUE) {
273                         seq_puts(seq, ",errors=remount-ro");
274                 }
275         }
276         if (test_opt(sb, ERRORS_CONT))
277                 seq_puts(seq, ",errors=continue");
278         if (test_opt(sb, ERRORS_PANIC))
279                 seq_puts(seq, ",errors=panic");
280         if (test_opt(sb, NO_UID32))
281                 seq_puts(seq, ",nouid32");
282         if (test_opt(sb, DEBUG))
283                 seq_puts(seq, ",debug");
284         if (test_opt(sb, OLDALLOC))
285                 seq_puts(seq, ",oldalloc");
286 
287 #ifdef CONFIG_EXT2_FS_XATTR
288         if (test_opt(sb, XATTR_USER))
289                 seq_puts(seq, ",user_xattr");
290         if (!test_opt(sb, XATTR_USER) &&
291             (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
292                 seq_puts(seq, ",nouser_xattr");
293         }
294 #endif
295 
296 #ifdef CONFIG_EXT2_FS_POSIX_ACL
297         if (test_opt(sb, POSIX_ACL))
298                 seq_puts(seq, ",acl");
299         if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
300                 seq_puts(seq, ",noacl");
301 #endif
302 
303         if (test_opt(sb, NOBH))
304                 seq_puts(seq, ",nobh");
305 
306         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
307                 seq_puts(seq, ",usrquota");
308 
309         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
310                 seq_puts(seq, ",grpquota");
311 
312         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
313                 seq_puts(seq, ",xip");
314 
315         if (sbi->s_mount_opt & EXT2_MOUNT_DAX)
316                 seq_puts(seq, ",dax");
317 
318         if (!test_opt(sb, RESERVATION))
319                 seq_puts(seq, ",noreservation");
320 
321         spin_unlock(&sbi->s_lock);
322         return 0;
323 }
324 
325 #ifdef CONFIG_QUOTA
326 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
327 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
328 static int ext2_quota_on(struct super_block *sb, int type, int format_id,
329                          const struct path *path);
330 static struct dquot **ext2_get_dquots(struct inode *inode)
331 {
332         return EXT2_I(inode)->i_dquot;
333 }
334 
335 static const struct quotactl_ops ext2_quotactl_ops = {
336         .quota_on       = ext2_quota_on,
337         .quota_off      = ext2_quota_off,
338         .quota_sync     = dquot_quota_sync,
339         .get_state      = dquot_get_state,
340         .set_info       = dquot_set_dqinfo,
341         .get_dqblk      = dquot_get_dqblk,
342         .set_dqblk      = dquot_set_dqblk,
343         .get_nextdqblk  = dquot_get_next_dqblk,
344 };
345 #endif
346 
347 static const struct super_operations ext2_sops = {
348         .alloc_inode    = ext2_alloc_inode,
349         .free_inode     = ext2_free_in_core_inode,
350         .write_inode    = ext2_write_inode,
351         .evict_inode    = ext2_evict_inode,
352         .put_super      = ext2_put_super,
353         .sync_fs        = ext2_sync_fs,
354         .freeze_fs      = ext2_freeze,
355         .unfreeze_fs    = ext2_unfreeze,
356         .statfs         = ext2_statfs,
357         .remount_fs     = ext2_remount,
358         .show_options   = ext2_show_options,
359 #ifdef CONFIG_QUOTA
360         .quota_read     = ext2_quota_read,
361         .quota_write    = ext2_quota_write,
362         .get_dquots     = ext2_get_dquots,
363 #endif
364 };
365 
366 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
367                 u64 ino, u32 generation)
368 {
369         struct inode *inode;
370 
371         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
372                 return ERR_PTR(-ESTALE);
373         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
374                 return ERR_PTR(-ESTALE);
375 
376         /*
377          * ext2_iget isn't quite right if the inode is currently unallocated!
378          * However ext2_iget currently does appropriate checks to handle stale
379          * inodes so everything is OK.
380          */
381         inode = ext2_iget(sb, ino);
382         if (IS_ERR(inode))
383                 return ERR_CAST(inode);
384         if (generation && inode->i_generation != generation) {
385                 /* we didn't find the right inode.. */
386                 iput(inode);
387                 return ERR_PTR(-ESTALE);
388         }
389         return inode;
390 }
391 
392 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
393                 int fh_len, int fh_type)
394 {
395         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
396                                     ext2_nfs_get_inode);
397 }
398 
399 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
400                 int fh_len, int fh_type)
401 {
402         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
403                                     ext2_nfs_get_inode);
404 }
405 
406 static const struct export_operations ext2_export_ops = {
407         .fh_to_dentry = ext2_fh_to_dentry,
408         .fh_to_parent = ext2_fh_to_parent,
409         .get_parent = ext2_get_parent,
410 };
411 
412 static unsigned long get_sb_block(void **data)
413 {
414         unsigned long   sb_block;
415         char            *options = (char *) *data;
416 
417         if (!options || strncmp(options, "sb=", 3) != 0)
418                 return 1;       /* Default location */
419         options += 3;
420         sb_block = simple_strtoul(options, &options, 0);
421         if (*options && *options != ',') {
422                 printk("EXT2-fs: Invalid sb specification: %s\n",
423                        (char *) *data);
424                 return 1;
425         }
426         if (*options == ',')
427                 options++;
428         *data = (void *) options;
429         return sb_block;
430 }
431 
432 enum {
433         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
434         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
435         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
436         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
437         Opt_acl, Opt_noacl, Opt_xip, Opt_dax, Opt_ignore, Opt_err, Opt_quota,
438         Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
439 };
440 
441 static const match_table_t tokens = {
442         {Opt_bsd_df, "bsddf"},
443         {Opt_minix_df, "minixdf"},
444         {Opt_grpid, "grpid"},
445         {Opt_grpid, "bsdgroups"},
446         {Opt_nogrpid, "nogrpid"},
447         {Opt_nogrpid, "sysvgroups"},
448         {Opt_resgid, "resgid=%u"},
449         {Opt_resuid, "resuid=%u"},
450         {Opt_sb, "sb=%u"},
451         {Opt_err_cont, "errors=continue"},
452         {Opt_err_panic, "errors=panic"},
453         {Opt_err_ro, "errors=remount-ro"},
454         {Opt_nouid32, "nouid32"},
455         {Opt_nocheck, "check=none"},
456         {Opt_nocheck, "nocheck"},
457         {Opt_debug, "debug"},
458         {Opt_oldalloc, "oldalloc"},
459         {Opt_orlov, "orlov"},
460         {Opt_nobh, "nobh"},
461         {Opt_user_xattr, "user_xattr"},
462         {Opt_nouser_xattr, "nouser_xattr"},
463         {Opt_acl, "acl"},
464         {Opt_noacl, "noacl"},
465         {Opt_xip, "xip"},
466         {Opt_dax, "dax"},
467         {Opt_grpquota, "grpquota"},
468         {Opt_ignore, "noquota"},
469         {Opt_quota, "quota"},
470         {Opt_usrquota, "usrquota"},
471         {Opt_reservation, "reservation"},
472         {Opt_noreservation, "noreservation"},
473         {Opt_err, NULL}
474 };
475 
476 static int parse_options(char *options, struct super_block *sb,
477                          struct ext2_mount_options *opts)
478 {
479         char *p;
480         substring_t args[MAX_OPT_ARGS];
481         int option;
482         kuid_t uid;
483         kgid_t gid;
484 
485         if (!options)
486                 return 1;
487 
488         while ((p = strsep (&options, ",")) != NULL) {
489                 int token;
490                 if (!*p)
491                         continue;
492 
493                 token = match_token(p, tokens, args);
494                 switch (token) {
495                 case Opt_bsd_df:
496                         clear_opt (opts->s_mount_opt, MINIX_DF);
497                         break;
498                 case Opt_minix_df:
499                         set_opt (opts->s_mount_opt, MINIX_DF);
500                         break;
501                 case Opt_grpid:
502                         set_opt (opts->s_mount_opt, GRPID);
503                         break;
504                 case Opt_nogrpid:
505                         clear_opt (opts->s_mount_opt, GRPID);
506                         break;
507                 case Opt_resuid:
508                         if (match_int(&args[0], &option))
509                                 return 0;
510                         uid = make_kuid(current_user_ns(), option);
511                         if (!uid_valid(uid)) {
512                                 ext2_msg(sb, KERN_ERR, "Invalid uid value %d", option);
513                                 return 0;
514 
515                         }
516                         opts->s_resuid = uid;
517                         break;
518                 case Opt_resgid:
519                         if (match_int(&args[0], &option))
520                                 return 0;
521                         gid = make_kgid(current_user_ns(), option);
522                         if (!gid_valid(gid)) {
523                                 ext2_msg(sb, KERN_ERR, "Invalid gid value %d", option);
524                                 return 0;
525                         }
526                         opts->s_resgid = gid;
527                         break;
528                 case Opt_sb:
529                         /* handled by get_sb_block() instead of here */
530                         /* *sb_block = match_int(&args[0]); */
531                         break;
532                 case Opt_err_panic:
533                         clear_opt (opts->s_mount_opt, ERRORS_CONT);
534                         clear_opt (opts->s_mount_opt, ERRORS_RO);
535                         set_opt (opts->s_mount_opt, ERRORS_PANIC);
536                         break;
537                 case Opt_err_ro:
538                         clear_opt (opts->s_mount_opt, ERRORS_CONT);
539                         clear_opt (opts->s_mount_opt, ERRORS_PANIC);
540                         set_opt (opts->s_mount_opt, ERRORS_RO);
541                         break;
542                 case Opt_err_cont:
543                         clear_opt (opts->s_mount_opt, ERRORS_RO);
544                         clear_opt (opts->s_mount_opt, ERRORS_PANIC);
545                         set_opt (opts->s_mount_opt, ERRORS_CONT);
546                         break;
547                 case Opt_nouid32:
548                         set_opt (opts->s_mount_opt, NO_UID32);
549                         break;
550                 case Opt_nocheck:
551                         ext2_msg(sb, KERN_WARNING,
552                                 "Option nocheck/check=none is deprecated and"
553                                 " will be removed in June 2020.");
554                         clear_opt (opts->s_mount_opt, CHECK);
555                         break;
556                 case Opt_debug:
557                         set_opt (opts->s_mount_opt, DEBUG);
558                         break;
559                 case Opt_oldalloc:
560                         set_opt (opts->s_mount_opt, OLDALLOC);
561                         break;
562                 case Opt_orlov:
563                         clear_opt (opts->s_mount_opt, OLDALLOC);
564                         break;
565                 case Opt_nobh:
566                         set_opt (opts->s_mount_opt, NOBH);
567                         break;
568 #ifdef CONFIG_EXT2_FS_XATTR
569                 case Opt_user_xattr:
570                         set_opt (opts->s_mount_opt, XATTR_USER);
571                         break;
572                 case Opt_nouser_xattr:
573                         clear_opt (opts->s_mount_opt, XATTR_USER);
574                         break;
575 #else
576                 case Opt_user_xattr:
577                 case Opt_nouser_xattr:
578                         ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
579                                 "not supported");
580                         break;
581 #endif
582 #ifdef CONFIG_EXT2_FS_POSIX_ACL
583                 case Opt_acl:
584                         set_opt(opts->s_mount_opt, POSIX_ACL);
585                         break;
586                 case Opt_noacl:
587                         clear_opt(opts->s_mount_opt, POSIX_ACL);
588                         break;
589 #else
590                 case Opt_acl:
591                 case Opt_noacl:
592                         ext2_msg(sb, KERN_INFO,
593                                 "(no)acl options not supported");
594                         break;
595 #endif
596                 case Opt_xip:
597                         ext2_msg(sb, KERN_INFO, "use dax instead of xip");
598                         set_opt(opts->s_mount_opt, XIP);
599                         /* Fall through */
600                 case Opt_dax:
601 #ifdef CONFIG_FS_DAX
602                         ext2_msg(sb, KERN_WARNING,
603                 "DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
604                         set_opt(opts->s_mount_opt, DAX);
605 #else
606                         ext2_msg(sb, KERN_INFO, "dax option not supported");
607 #endif
608                         break;
609 
610 #if defined(CONFIG_QUOTA)
611                 case Opt_quota:
612                 case Opt_usrquota:
613                         set_opt(opts->s_mount_opt, USRQUOTA);
614                         break;
615 
616                 case Opt_grpquota:
617                         set_opt(opts->s_mount_opt, GRPQUOTA);
618                         break;
619 #else
620                 case Opt_quota:
621                 case Opt_usrquota:
622                 case Opt_grpquota:
623                         ext2_msg(sb, KERN_INFO,
624                                 "quota operations not supported");
625                         break;
626 #endif
627 
628                 case Opt_reservation:
629                         set_opt(opts->s_mount_opt, RESERVATION);
630                         ext2_msg(sb, KERN_INFO, "reservations ON");
631                         break;
632                 case Opt_noreservation:
633                         clear_opt(opts->s_mount_opt, RESERVATION);
634                         ext2_msg(sb, KERN_INFO, "reservations OFF");
635                         break;
636                 case Opt_ignore:
637                         break;
638                 default:
639                         return 0;
640                 }
641         }
642         return 1;
643 }
644 
645 static int ext2_setup_super (struct super_block * sb,
646                               struct ext2_super_block * es,
647                               int read_only)
648 {
649         int res = 0;
650         struct ext2_sb_info *sbi = EXT2_SB(sb);
651 
652         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
653                 ext2_msg(sb, KERN_ERR,
654                         "error: revision level too high, "
655                         "forcing read-only mode");
656                 res = SB_RDONLY;
657         }
658         if (read_only)
659                 return res;
660         if (!(sbi->s_mount_state & EXT2_VALID_FS))
661                 ext2_msg(sb, KERN_WARNING,
662                         "warning: mounting unchecked fs, "
663                         "running e2fsck is recommended");
664         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
665                 ext2_msg(sb, KERN_WARNING,
666                         "warning: mounting fs with errors, "
667                         "running e2fsck is recommended");
668         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
669                  le16_to_cpu(es->s_mnt_count) >=
670                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
671                 ext2_msg(sb, KERN_WARNING,
672                         "warning: maximal mount count reached, "
673                         "running e2fsck is recommended");
674         else if (le32_to_cpu(es->s_checkinterval) &&
675                 (le32_to_cpu(es->s_lastcheck) +
676                         le32_to_cpu(es->s_checkinterval) <=
677                         ktime_get_real_seconds()))
678                 ext2_msg(sb, KERN_WARNING,
679                         "warning: checktime reached, "
680                         "running e2fsck is recommended");
681         if (!le16_to_cpu(es->s_max_mnt_count))
682                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
683         le16_add_cpu(&es->s_mnt_count, 1);
684         if (test_opt (sb, DEBUG))
685                 ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
686                         "bpg=%lu, ipg=%lu, mo=%04lx]",
687                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
688                         sbi->s_frag_size,
689                         sbi->s_groups_count,
690                         EXT2_BLOCKS_PER_GROUP(sb),
691                         EXT2_INODES_PER_GROUP(sb),
692                         sbi->s_mount_opt);
693         return res;
694 }
695 
696 static int ext2_check_descriptors(struct super_block *sb)
697 {
698         int i;
699         struct ext2_sb_info *sbi = EXT2_SB(sb);
700 
701         ext2_debug ("Checking group descriptors");
702 
703         for (i = 0; i < sbi->s_groups_count; i++) {
704                 struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
705                 ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
706                 ext2_fsblk_t last_block;
707 
708                 if (i == sbi->s_groups_count - 1)
709                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
710                 else
711                         last_block = first_block +
712                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
713 
714                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
715                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
716                 {
717                         ext2_error (sb, "ext2_check_descriptors",
718                                     "Block bitmap for group %d"
719                                     " not in group (block %lu)!",
720                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
721                         return 0;
722                 }
723                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
724                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
725                 {
726                         ext2_error (sb, "ext2_check_descriptors",
727                                     "Inode bitmap for group %d"
728                                     " not in group (block %lu)!",
729                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
730                         return 0;
731                 }
732                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
733                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
734                     last_block)
735                 {
736                         ext2_error (sb, "ext2_check_descriptors",
737                                     "Inode table for group %d"
738                                     " not in group (block %lu)!",
739                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
740                         return 0;
741                 }
742         }
743         return 1;
744 }
745 
746 /*
747  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
748  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
749  * We need to be 1 filesystem block less than the 2^32 sector limit.
750  */
751 static loff_t ext2_max_size(int bits)
752 {
753         loff_t res = EXT2_NDIR_BLOCKS;
754         int meta_blocks;
755         unsigned int upper_limit;
756         unsigned int ppb = 1 << (bits-2);
757 
758         /* This is calculated to be the largest file size for a
759          * dense, file such that the total number of
760          * sectors in the file, including data and all indirect blocks,
761          * does not exceed 2^32 -1
762          * __u32 i_blocks representing the total number of
763          * 512 bytes blocks of the file
764          */
765         upper_limit = (1LL << 32) - 1;
766 
767         /* total blocks in file system block size */
768         upper_limit >>= (bits - 9);
769 
770         /* Compute how many blocks we can address by block tree */
771         res += 1LL << (bits-2);
772         res += 1LL << (2*(bits-2));
773         res += 1LL << (3*(bits-2));
774         /* Does block tree limit file size? */
775         if (res < upper_limit)
776                 goto check_lfs;
777 
778         res = upper_limit;
779         /* How many metadata blocks are needed for addressing upper_limit? */
780         upper_limit -= EXT2_NDIR_BLOCKS;
781         /* indirect blocks */
782         meta_blocks = 1;
783         upper_limit -= ppb;
784         /* double indirect blocks */
785         if (upper_limit < ppb * ppb) {
786                 meta_blocks += 1 + DIV_ROUND_UP(upper_limit, ppb);
787                 res -= meta_blocks;
788                 goto check_lfs;
789         }
790         meta_blocks += 1 + ppb;
791         upper_limit -= ppb * ppb;
792         /* tripple indirect blocks for the rest */
793         meta_blocks += 1 + DIV_ROUND_UP(upper_limit, ppb) +
794                 DIV_ROUND_UP(upper_limit, ppb*ppb);
795         res -= meta_blocks;
796 check_lfs:
797         res <<= bits;
798         if (res > MAX_LFS_FILESIZE)
799                 res = MAX_LFS_FILESIZE;
800 
801         return res;
802 }
803 
804 static unsigned long descriptor_loc(struct super_block *sb,
805                                     unsigned long logic_sb_block,
806                                     int nr)
807 {
808         struct ext2_sb_info *sbi = EXT2_SB(sb);
809         unsigned long bg, first_meta_bg;
810         int has_super = 0;
811         
812         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
813 
814         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
815             nr < first_meta_bg)
816                 return (logic_sb_block + nr + 1);
817         bg = sbi->s_desc_per_block * nr;
818         if (ext2_bg_has_super(sb, bg))
819                 has_super = 1;
820 
821         return ext2_group_first_block_no(sb, bg) + has_super;
822 }
823 
824 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
825 {
826         struct dax_device *dax_dev = fs_dax_get_by_bdev(sb->s_bdev);
827         struct buffer_head * bh;
828         struct ext2_sb_info * sbi;
829         struct ext2_super_block * es;
830         struct inode *root;
831         unsigned long block;
832         unsigned long sb_block = get_sb_block(&data);
833         unsigned long logic_sb_block;
834         unsigned long offset = 0;
835         unsigned long def_mount_opts;
836         long ret = -ENOMEM;
837         int blocksize = BLOCK_SIZE;
838         int db_count;
839         int i, j;
840         __le32 features;
841         int err;
842         struct ext2_mount_options opts;
843 
844         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
845         if (!sbi)
846                 goto failed;
847 
848         sbi->s_blockgroup_lock =
849                 kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
850         if (!sbi->s_blockgroup_lock) {
851                 kfree(sbi);
852                 goto failed;
853         }
854         sb->s_fs_info = sbi;
855         sbi->s_sb_block = sb_block;
856         sbi->s_daxdev = dax_dev;
857 
858         spin_lock_init(&sbi->s_lock);
859         ret = -EINVAL;
860 
861         /*
862          * See what the current blocksize for the device is, and
863          * use that as the blocksize.  Otherwise (or if the blocksize
864          * is smaller than the default) use the default.
865          * This is important for devices that have a hardware
866          * sectorsize that is larger than the default.
867          */
868         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
869         if (!blocksize) {
870                 ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
871                 goto failed_sbi;
872         }
873 
874         /*
875          * If the superblock doesn't start on a hardware sector boundary,
876          * calculate the offset.  
877          */
878         if (blocksize != BLOCK_SIZE) {
879                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
880                 offset = (sb_block*BLOCK_SIZE) % blocksize;
881         } else {
882                 logic_sb_block = sb_block;
883         }
884 
885         if (!(bh = sb_bread(sb, logic_sb_block))) {
886                 ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
887                 goto failed_sbi;
888         }
889         /*
890          * Note: s_es must be initialized as soon as possible because
891          *       some ext2 macro-instructions depend on its value
892          */
893         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
894         sbi->s_es = es;
895         sb->s_magic = le16_to_cpu(es->s_magic);
896 
897         if (sb->s_magic != EXT2_SUPER_MAGIC)
898                 goto cantfind_ext2;
899 
900         opts.s_mount_opt = 0;
901         /* Set defaults before we parse the mount options */
902         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
903         if (def_mount_opts & EXT2_DEFM_DEBUG)
904                 set_opt(opts.s_mount_opt, DEBUG);
905         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
906                 set_opt(opts.s_mount_opt, GRPID);
907         if (def_mount_opts & EXT2_DEFM_UID16)
908                 set_opt(opts.s_mount_opt, NO_UID32);
909 #ifdef CONFIG_EXT2_FS_XATTR
910         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
911                 set_opt(opts.s_mount_opt, XATTR_USER);
912 #endif
913 #ifdef CONFIG_EXT2_FS_POSIX_ACL
914         if (def_mount_opts & EXT2_DEFM_ACL)
915                 set_opt(opts.s_mount_opt, POSIX_ACL);
916 #endif
917         
918         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
919                 set_opt(opts.s_mount_opt, ERRORS_PANIC);
920         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
921                 set_opt(opts.s_mount_opt, ERRORS_CONT);
922         else
923                 set_opt(opts.s_mount_opt, ERRORS_RO);
924 
925         opts.s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
926         opts.s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
927         
928         set_opt(opts.s_mount_opt, RESERVATION);
929 
930         if (!parse_options((char *) data, sb, &opts))
931                 goto failed_mount;
932 
933         sbi->s_mount_opt = opts.s_mount_opt;
934         sbi->s_resuid = opts.s_resuid;
935         sbi->s_resgid = opts.s_resgid;
936 
937         sb->s_flags = (sb->s_flags & ~SB_POSIXACL) |
938                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
939                  SB_POSIXACL : 0);
940         sb->s_iflags |= SB_I_CGROUPWB;
941 
942         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
943             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
944              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
945              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
946                 ext2_msg(sb, KERN_WARNING,
947                         "warning: feature flags set on rev 0 fs, "
948                         "running e2fsck is recommended");
949         /*
950          * Check feature flags regardless of the revision level, since we
951          * previously didn't change the revision level when setting the flags,
952          * so there is a chance incompat flags are set on a rev 0 filesystem.
953          */
954         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
955         if (features) {
956                 ext2_msg(sb, KERN_ERR,  "error: couldn't mount because of "
957                        "unsupported optional features (%x)",
958                         le32_to_cpu(features));
959                 goto failed_mount;
960         }
961         if (!sb_rdonly(sb) && (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
962                 ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
963                        "unsupported optional features (%x)",
964                        le32_to_cpu(features));
965                 goto failed_mount;
966         }
967 
968         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
969 
970         if (sbi->s_mount_opt & EXT2_MOUNT_DAX) {
971                 if (!bdev_dax_supported(sb->s_bdev, blocksize)) {
972                         ext2_msg(sb, KERN_ERR,
973                                 "DAX unsupported by block device. Turning off DAX.");
974                         sbi->s_mount_opt &= ~EXT2_MOUNT_DAX;
975                 }
976         }
977 
978         /* If the blocksize doesn't match, re-read the thing.. */
979         if (sb->s_blocksize != blocksize) {
980                 brelse(bh);
981 
982                 if (!sb_set_blocksize(sb, blocksize)) {
983                         ext2_msg(sb, KERN_ERR,
984                                 "error: bad blocksize %d", blocksize);
985                         goto failed_sbi;
986                 }
987 
988                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
989                 offset = (sb_block*BLOCK_SIZE) % blocksize;
990                 bh = sb_bread(sb, logic_sb_block);
991                 if(!bh) {
992                         ext2_msg(sb, KERN_ERR, "error: couldn't read"
993                                 "superblock on 2nd try");
994                         goto failed_sbi;
995                 }
996                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
997                 sbi->s_es = es;
998                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
999                         ext2_msg(sb, KERN_ERR, "error: magic mismatch");
1000                         goto failed_mount;
1001                 }
1002         }
1003 
1004         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
1005         sb->s_max_links = EXT2_LINK_MAX;
1006 
1007         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
1008                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
1009                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
1010         } else {
1011                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
1012                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
1013                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
1014                     !is_power_of_2(sbi->s_inode_size) ||
1015                     (sbi->s_inode_size > blocksize)) {
1016                         ext2_msg(sb, KERN_ERR,
1017                                 "error: unsupported inode size: %d",
1018                                 sbi->s_inode_size);
1019                         goto failed_mount;
1020                 }
1021         }
1022 
1023         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
1024                                    le32_to_cpu(es->s_log_frag_size);
1025         if (sbi->s_frag_size == 0)
1026                 goto cantfind_ext2;
1027         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
1028 
1029         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
1030         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
1031         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
1032 
1033         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
1034         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
1035                 goto cantfind_ext2;
1036         sbi->s_itb_per_group = sbi->s_inodes_per_group /
1037                                         sbi->s_inodes_per_block;
1038         sbi->s_desc_per_block = sb->s_blocksize /
1039                                         sizeof (struct ext2_group_desc);
1040         sbi->s_sbh = bh;
1041         sbi->s_mount_state = le16_to_cpu(es->s_state);
1042         sbi->s_addr_per_block_bits =
1043                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
1044         sbi->s_desc_per_block_bits =
1045                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
1046 
1047         if (sb->s_magic != EXT2_SUPER_MAGIC)
1048                 goto cantfind_ext2;
1049 
1050         if (sb->s_blocksize != bh->b_size) {
1051                 if (!silent)
1052                         ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
1053                 goto failed_mount;
1054         }
1055 
1056         if (sb->s_blocksize != sbi->s_frag_size) {
1057                 ext2_msg(sb, KERN_ERR,
1058                         "error: fragsize %lu != blocksize %lu"
1059                         "(not supported yet)",
1060                         sbi->s_frag_size, sb->s_blocksize);
1061                 goto failed_mount;
1062         }
1063 
1064         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
1065                 ext2_msg(sb, KERN_ERR,
1066                         "error: #blocks per group too big: %lu",
1067                         sbi->s_blocks_per_group);
1068                 goto failed_mount;
1069         }
1070         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
1071                 ext2_msg(sb, KERN_ERR,
1072                         "error: #fragments per group too big: %lu",
1073                         sbi->s_frags_per_group);
1074                 goto failed_mount;
1075         }
1076         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
1077                 ext2_msg(sb, KERN_ERR,
1078                         "error: #inodes per group too big: %lu",
1079                         sbi->s_inodes_per_group);
1080                 goto failed_mount;
1081         }
1082 
1083         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
1084                 goto cantfind_ext2;
1085         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
1086                                 le32_to_cpu(es->s_first_data_block) - 1)
1087                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
1088         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
1089                    EXT2_DESC_PER_BLOCK(sb);
1090         sbi->s_group_desc = kmalloc_array (db_count,
1091                                            sizeof(struct buffer_head *),
1092                                            GFP_KERNEL);
1093         if (sbi->s_group_desc == NULL) {
1094                 ret = -ENOMEM;
1095                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
1096                 goto failed_mount;
1097         }
1098         bgl_lock_init(sbi->s_blockgroup_lock);
1099         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
1100         if (!sbi->s_debts) {
1101                 ret = -ENOMEM;
1102                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
1103                 goto failed_mount_group_desc;
1104         }
1105         for (i = 0; i < db_count; i++) {
1106                 block = descriptor_loc(sb, logic_sb_block, i);
1107                 sbi->s_group_desc[i] = sb_bread(sb, block);
1108                 if (!sbi->s_group_desc[i]) {
1109                         for (j = 0; j < i; j++)
1110                                 brelse (sbi->s_group_desc[j]);
1111                         ext2_msg(sb, KERN_ERR,
1112                                 "error: unable to read group descriptors");
1113                         goto failed_mount_group_desc;
1114                 }
1115         }
1116         if (!ext2_check_descriptors (sb)) {
1117                 ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1118                 goto failed_mount2;
1119         }
1120         sbi->s_gdb_count = db_count;
1121         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1122         spin_lock_init(&sbi->s_next_gen_lock);
1123 
1124         /* per fileystem reservation list head & lock */
1125         spin_lock_init(&sbi->s_rsv_window_lock);
1126         sbi->s_rsv_window_root = RB_ROOT;
1127         /*
1128          * Add a single, static dummy reservation to the start of the
1129          * reservation window list --- it gives us a placeholder for
1130          * append-at-start-of-list which makes the allocation logic
1131          * _much_ simpler.
1132          */
1133         sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1134         sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1135         sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1136         sbi->s_rsv_window_head.rsv_goal_size = 0;
1137         ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1138 
1139         err = percpu_counter_init(&sbi->s_freeblocks_counter,
1140                                 ext2_count_free_blocks(sb), GFP_KERNEL);
1141         if (!err) {
1142                 err = percpu_counter_init(&sbi->s_freeinodes_counter,
1143                                 ext2_count_free_inodes(sb), GFP_KERNEL);
1144         }
1145         if (!err) {
1146                 err = percpu_counter_init(&sbi->s_dirs_counter,
1147                                 ext2_count_dirs(sb), GFP_KERNEL);
1148         }
1149         if (err) {
1150                 ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1151                 goto failed_mount3;
1152         }
1153 
1154 #ifdef CONFIG_EXT2_FS_XATTR
1155         sbi->s_ea_block_cache = ext2_xattr_create_cache();
1156         if (!sbi->s_ea_block_cache) {
1157                 ret = -ENOMEM;
1158                 ext2_msg(sb, KERN_ERR, "Failed to create ea_block_cache");
1159                 goto failed_mount3;
1160         }
1161 #endif
1162         /*
1163          * set up enough so that it can read an inode
1164          */
1165         sb->s_op = &ext2_sops;
1166         sb->s_export_op = &ext2_export_ops;
1167         sb->s_xattr = ext2_xattr_handlers;
1168 
1169 #ifdef CONFIG_QUOTA
1170         sb->dq_op = &dquot_operations;
1171         sb->s_qcop = &ext2_quotactl_ops;
1172         sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP;
1173 #endif
1174 
1175         root = ext2_iget(sb, EXT2_ROOT_INO);
1176         if (IS_ERR(root)) {
1177                 ret = PTR_ERR(root);
1178                 goto failed_mount3;
1179         }
1180         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1181                 iput(root);
1182                 ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1183                 goto failed_mount3;
1184         }
1185 
1186         sb->s_root = d_make_root(root);
1187         if (!sb->s_root) {
1188                 ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1189                 ret = -ENOMEM;
1190                 goto failed_mount3;
1191         }
1192         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1193                 ext2_msg(sb, KERN_WARNING,
1194                         "warning: mounting ext3 filesystem as ext2");
1195         if (ext2_setup_super (sb, es, sb_rdonly(sb)))
1196                 sb->s_flags |= SB_RDONLY;
1197         ext2_write_super(sb);
1198         return 0;
1199 
1200 cantfind_ext2:
1201         if (!silent)
1202                 ext2_msg(sb, KERN_ERR,
1203                         "error: can't find an ext2 filesystem on dev %s.",
1204                         sb->s_id);
1205         goto failed_mount;
1206 failed_mount3:
1207         ext2_xattr_destroy_cache(sbi->s_ea_block_cache);
1208         percpu_counter_destroy(&sbi->s_freeblocks_counter);
1209         percpu_counter_destroy(&sbi->s_freeinodes_counter);
1210         percpu_counter_destroy(&sbi->s_dirs_counter);
1211 failed_mount2:
1212         for (i = 0; i < db_count; i++)
1213                 brelse(sbi->s_group_desc[i]);
1214 failed_mount_group_desc:
1215         kfree(sbi->s_group_desc);
1216         kfree(sbi->s_debts);
1217 failed_mount:
1218         brelse(bh);
1219 failed_sbi:
1220         sb->s_fs_info = NULL;
1221         kfree(sbi->s_blockgroup_lock);
1222         kfree(sbi);
1223 failed:
1224         fs_put_dax(dax_dev);
1225         return ret;
1226 }
1227 
1228 static void ext2_clear_super_error(struct super_block *sb)
1229 {
1230         struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1231 
1232         if (buffer_write_io_error(sbh)) {
1233                 /*
1234                  * Oh, dear.  A previous attempt to write the
1235                  * superblock failed.  This could happen because the
1236                  * USB device was yanked out.  Or it could happen to
1237                  * be a transient write error and maybe the block will
1238                  * be remapped.  Nothing we can do but to retry the
1239                  * write and hope for the best.
1240                  */
1241                 ext2_msg(sb, KERN_ERR,
1242                        "previous I/O error to superblock detected");
1243                 clear_buffer_write_io_error(sbh);
1244                 set_buffer_uptodate(sbh);
1245         }
1246 }
1247 
1248 void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
1249                      int wait)
1250 {
1251         ext2_clear_super_error(sb);
1252         spin_lock(&EXT2_SB(sb)->s_lock);
1253         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1254         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1255         es->s_wtime = cpu_to_le32(ktime_get_real_seconds());
1256         /* unlock before we do IO */
1257         spin_unlock(&EXT2_SB(sb)->s_lock);
1258         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1259         if (wait)
1260                 sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1261 }
1262 
1263 /*
1264  * In the second extended file system, it is not necessary to
1265  * write the super block since we use a mapping of the
1266  * disk super block in a buffer.
1267  *
1268  * However, this function is still used to set the fs valid
1269  * flags to 0.  We need to set this flag to 0 since the fs
1270  * may have been checked while mounted and e2fsck may have
1271  * set s_state to EXT2_VALID_FS after some corrections.
1272  */
1273 static int ext2_sync_fs(struct super_block *sb, int wait)
1274 {
1275         struct ext2_sb_info *sbi = EXT2_SB(sb);
1276         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1277 
1278         /*
1279          * Write quota structures to quota file, sync_blockdev() will write
1280          * them to disk later
1281          */
1282         dquot_writeback_dquots(sb, -1);
1283 
1284         spin_lock(&sbi->s_lock);
1285         if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1286                 ext2_debug("setting valid to 0\n");
1287                 es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1288         }
1289         spin_unlock(&sbi->s_lock);
1290         ext2_sync_super(sb, es, wait);
1291         return 0;
1292 }
1293 
1294 static int ext2_freeze(struct super_block *sb)
1295 {
1296         struct ext2_sb_info *sbi = EXT2_SB(sb);
1297 
1298         /*
1299          * Open but unlinked files present? Keep EXT2_VALID_FS flag cleared
1300          * because we have unattached inodes and thus filesystem is not fully
1301          * consistent.
1302          */
1303         if (atomic_long_read(&sb->s_remove_count)) {
1304                 ext2_sync_fs(sb, 1);
1305                 return 0;
1306         }
1307         /* Set EXT2_FS_VALID flag */
1308         spin_lock(&sbi->s_lock);
1309         sbi->s_es->s_state = cpu_to_le16(sbi->s_mount_state);
1310         spin_unlock(&sbi->s_lock);
1311         ext2_sync_super(sb, sbi->s_es, 1);
1312 
1313         return 0;
1314 }
1315 
1316 static int ext2_unfreeze(struct super_block *sb)
1317 {
1318         /* Just write sb to clear EXT2_VALID_FS flag */
1319         ext2_write_super(sb);
1320 
1321         return 0;
1322 }
1323 
1324 static void ext2_write_super(struct super_block *sb)
1325 {
1326         if (!sb_rdonly(sb))
1327                 ext2_sync_fs(sb, 1);
1328 }
1329 
1330 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1331 {
1332         struct ext2_sb_info * sbi = EXT2_SB(sb);
1333         struct ext2_super_block * es;
1334         struct ext2_mount_options new_opts;
1335         int err;
1336 
1337         sync_filesystem(sb);
1338 
1339         spin_lock(&sbi->s_lock);
1340         new_opts.s_mount_opt = sbi->s_mount_opt;
1341         new_opts.s_resuid = sbi->s_resuid;
1342         new_opts.s_resgid = sbi->s_resgid;
1343         spin_unlock(&sbi->s_lock);
1344 
1345         if (!parse_options(data, sb, &new_opts))
1346                 return -EINVAL;
1347 
1348         spin_lock(&sbi->s_lock);
1349         es = sbi->s_es;
1350         if ((sbi->s_mount_opt ^ new_opts.s_mount_opt) & EXT2_MOUNT_DAX) {
1351                 ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1352                          "dax flag with busy inodes while remounting");
1353                 new_opts.s_mount_opt ^= EXT2_MOUNT_DAX;
1354         }
1355         if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))
1356                 goto out_set;
1357         if (*flags & SB_RDONLY) {
1358                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1359                     !(sbi->s_mount_state & EXT2_VALID_FS))
1360                         goto out_set;
1361 
1362                 /*
1363                  * OK, we are remounting a valid rw partition rdonly, so set
1364                  * the rdonly flag and then mark the partition as valid again.
1365                  */
1366                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1367                 es->s_mtime = cpu_to_le32(ktime_get_real_seconds());
1368                 spin_unlock(&sbi->s_lock);
1369 
1370                 err = dquot_suspend(sb, -1);
1371                 if (err < 0)
1372                         return err;
1373 
1374                 ext2_sync_super(sb, es, 1);
1375         } else {
1376                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1377                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1378                 if (ret) {
1379                         spin_unlock(&sbi->s_lock);
1380                         ext2_msg(sb, KERN_WARNING,
1381                                 "warning: couldn't remount RDWR because of "
1382                                 "unsupported optional features (%x).",
1383                                 le32_to_cpu(ret));
1384                         return -EROFS;
1385                 }
1386                 /*
1387                  * Mounting a RDONLY partition read-write, so reread and
1388                  * store the current valid flag.  (It may have been changed
1389                  * by e2fsck since we originally mounted the partition.)
1390                  */
1391                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1392                 if (!ext2_setup_super (sb, es, 0))
1393                         sb->s_flags &= ~SB_RDONLY;
1394                 spin_unlock(&sbi->s_lock);
1395 
1396                 ext2_write_super(sb);
1397 
1398                 dquot_resume(sb, -1);
1399         }
1400 
1401         spin_lock(&sbi->s_lock);
1402 out_set:
1403         sbi->s_mount_opt = new_opts.s_mount_opt;
1404         sbi->s_resuid = new_opts.s_resuid;
1405         sbi->s_resgid = new_opts.s_resgid;
1406         sb->s_flags = (sb->s_flags & ~SB_POSIXACL) |
1407                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? SB_POSIXACL : 0);
1408         spin_unlock(&sbi->s_lock);
1409 
1410         return 0;
1411 }
1412 
1413 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1414 {
1415         struct super_block *sb = dentry->d_sb;
1416         struct ext2_sb_info *sbi = EXT2_SB(sb);
1417         struct ext2_super_block *es = sbi->s_es;
1418         u64 fsid;
1419 
1420         spin_lock(&sbi->s_lock);
1421 
1422         if (test_opt (sb, MINIX_DF))
1423                 sbi->s_overhead_last = 0;
1424         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1425                 unsigned long i, overhead = 0;
1426                 smp_rmb();
1427 
1428                 /*
1429                  * Compute the overhead (FS structures). This is constant
1430                  * for a given filesystem unless the number of block groups
1431                  * changes so we cache the previous value until it does.
1432                  */
1433 
1434                 /*
1435                  * All of the blocks before first_data_block are
1436                  * overhead
1437                  */
1438                 overhead = le32_to_cpu(es->s_first_data_block);
1439 
1440                 /*
1441                  * Add the overhead attributed to the superblock and
1442                  * block group descriptors.  If the sparse superblocks
1443                  * feature is turned on, then not all groups have this.
1444                  */
1445                 for (i = 0; i < sbi->s_groups_count; i++)
1446                         overhead += ext2_bg_has_super(sb, i) +
1447                                 ext2_bg_num_gdb(sb, i);
1448 
1449                 /*
1450                  * Every block group has an inode bitmap, a block
1451                  * bitmap, and an inode table.
1452                  */
1453                 overhead += (sbi->s_groups_count *
1454                              (2 + sbi->s_itb_per_group));
1455                 sbi->s_overhead_last = overhead;
1456                 smp_wmb();
1457                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1458         }
1459 
1460         buf->f_type = EXT2_SUPER_MAGIC;
1461         buf->f_bsize = sb->s_blocksize;
1462         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1463         buf->f_bfree = ext2_count_free_blocks(sb);
1464         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1465         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1466         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1467                 buf->f_bavail = 0;
1468         buf->f_files = le32_to_cpu(es->s_inodes_count);
1469         buf->f_ffree = ext2_count_free_inodes(sb);
1470         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1471         buf->f_namelen = EXT2_NAME_LEN;
1472         fsid = le64_to_cpup((void *)es->s_uuid) ^
1473                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1474         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1475         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1476         spin_unlock(&sbi->s_lock);
1477         return 0;
1478 }
1479 
1480 static struct dentry *ext2_mount(struct file_system_type *fs_type,
1481         int flags, const char *dev_name, void *data)
1482 {
1483         return mount_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1484 }
1485 
1486 #ifdef CONFIG_QUOTA
1487 
1488 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1489  * acquiring the locks... As quota files are never truncated and quota code
1490  * itself serializes the operations (and no one else should touch the files)
1491  * we don't have to be afraid of races */
1492 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1493                                size_t len, loff_t off)
1494 {
1495         struct inode *inode = sb_dqopt(sb)->files[type];
1496         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1497         int err = 0;
1498         int offset = off & (sb->s_blocksize - 1);
1499         int tocopy;
1500         size_t toread;
1501         struct buffer_head tmp_bh;
1502         struct buffer_head *bh;
1503         loff_t i_size = i_size_read(inode);
1504 
1505         if (off > i_size)
1506                 return 0;
1507         if (off+len > i_size)
1508                 len = i_size-off;
1509         toread = len;
1510         while (toread > 0) {
1511                 tocopy = sb->s_blocksize - offset < toread ?
1512                                 sb->s_blocksize - offset : toread;
1513 
1514                 tmp_bh.b_state = 0;
1515                 tmp_bh.b_size = sb->s_blocksize;
1516                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1517                 if (err < 0)
1518                         return err;
1519                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1520                         memset(data, 0, tocopy);
1521                 else {
1522                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1523                         if (!bh)
1524                                 return -EIO;
1525                         memcpy(data, bh->b_data+offset, tocopy);
1526                         brelse(bh);
1527                 }
1528                 offset = 0;
1529                 toread -= tocopy;
1530                 data += tocopy;
1531                 blk++;
1532         }
1533         return len;
1534 }
1535 
1536 /* Write to quotafile */
1537 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1538                                 const char *data, size_t len, loff_t off)
1539 {
1540         struct inode *inode = sb_dqopt(sb)->files[type];
1541         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1542         int err = 0;
1543         int offset = off & (sb->s_blocksize - 1);
1544         int tocopy;
1545         size_t towrite = len;
1546         struct buffer_head tmp_bh;
1547         struct buffer_head *bh;
1548 
1549         while (towrite > 0) {
1550                 tocopy = sb->s_blocksize - offset < towrite ?
1551                                 sb->s_blocksize - offset : towrite;
1552 
1553                 tmp_bh.b_state = 0;
1554                 tmp_bh.b_size = sb->s_blocksize;
1555                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1556                 if (err < 0)
1557                         goto out;
1558                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1559                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1560                 else
1561                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1562                 if (unlikely(!bh)) {
1563                         err = -EIO;
1564                         goto out;
1565                 }
1566                 lock_buffer(bh);
1567                 memcpy(bh->b_data+offset, data, tocopy);
1568                 flush_dcache_page(bh->b_page);
1569                 set_buffer_uptodate(bh);
1570                 mark_buffer_dirty(bh);
1571                 unlock_buffer(bh);
1572                 brelse(bh);
1573                 offset = 0;
1574                 towrite -= tocopy;
1575                 data += tocopy;
1576                 blk++;
1577         }
1578 out:
1579         if (len == towrite)
1580                 return err;
1581         if (inode->i_size < off+len-towrite)
1582                 i_size_write(inode, off+len-towrite);
1583         inode_inc_iversion(inode);
1584         inode->i_mtime = inode->i_ctime = current_time(inode);
1585         mark_inode_dirty(inode);
1586         return len - towrite;
1587 }
1588 
1589 static int ext2_quota_on(struct super_block *sb, int type, int format_id,
1590                          const struct path *path)
1591 {
1592         int err;
1593         struct inode *inode;
1594 
1595         err = dquot_quota_on(sb, type, format_id, path);
1596         if (err)
1597                 return err;
1598 
1599         inode = d_inode(path->dentry);
1600         inode_lock(inode);
1601         EXT2_I(inode)->i_flags |= EXT2_NOATIME_FL | EXT2_IMMUTABLE_FL;
1602         inode_set_flags(inode, S_NOATIME | S_IMMUTABLE,
1603                         S_NOATIME | S_IMMUTABLE);
1604         inode_unlock(inode);
1605         mark_inode_dirty(inode);
1606 
1607         return 0;
1608 }
1609 
1610 static int ext2_quota_off(struct super_block *sb, int type)
1611 {
1612         struct inode *inode = sb_dqopt(sb)->files[type];
1613         int err;
1614 
1615         if (!inode || !igrab(inode))
1616                 goto out;
1617 
1618         err = dquot_quota_off(sb, type);
1619         if (err)
1620                 goto out_put;
1621 
1622         inode_lock(inode);
1623         EXT2_I(inode)->i_flags &= ~(EXT2_NOATIME_FL | EXT2_IMMUTABLE_FL);
1624         inode_set_flags(inode, 0, S_NOATIME | S_IMMUTABLE);
1625         inode_unlock(inode);
1626         mark_inode_dirty(inode);
1627 out_put:
1628         iput(inode);
1629         return err;
1630 out:
1631         return dquot_quota_off(sb, type);
1632 }
1633 
1634 #endif
1635 
1636 static struct file_system_type ext2_fs_type = {
1637         .owner          = THIS_MODULE,
1638         .name           = "ext2",
1639         .mount          = ext2_mount,
1640         .kill_sb        = kill_block_super,
1641         .fs_flags       = FS_REQUIRES_DEV,
1642 };
1643 MODULE_ALIAS_FS("ext2");
1644 
1645 static int __init init_ext2_fs(void)
1646 {
1647         int err;
1648 
1649         err = init_inodecache();
1650         if (err)
1651                 return err;
1652         err = register_filesystem(&ext2_fs_type);
1653         if (err)
1654                 goto out;
1655         return 0;
1656 out:
1657         destroy_inodecache();
1658         return err;
1659 }
1660 
1661 static void __exit exit_ext2_fs(void)
1662 {
1663         unregister_filesystem(&ext2_fs_type);
1664         destroy_inodecache();
1665 }
1666 
1667 MODULE_AUTHOR("Remy Card and others");
1668 MODULE_DESCRIPTION("Second Extended Filesystem");
1669 MODULE_LICENSE("GPL");
1670 module_init(init_ext2_fs)
1671 module_exit(exit_ext2_fs)
1672 

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