fs/ext2/super.c

   1 /*
   2  *  linux/fs/ext2/super.c
   3  *
   4  * Copyright (C) 1992, 1993, 1994, 1995
   5  * Remy Card (card@masi.ibp.fr)
   6  * Laboratoire MASI - Institut Blaise Pascal
   7  * Universite Pierre et Marie Curie (Paris VI)
   8  *
   9  *  from
  10  *
  11  *  linux/fs/minix/inode.c
  12  *
  13  *  Copyright (C) 1991, 1992  Linus Torvalds
  14  *
  15  *  Big-endian to little-endian byte-swapping/bitmaps by
  16  *        David S. Miller (davem@caip.rutgers.edu), 1995
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/string.h>
  21 #include <linux/fs.h>
  22 #include <linux/slab.h>
  23 #include <linux/init.h>
  24 #include <linux/blkdev.h>
  25 #include <linux/parser.h>
  26 #include <linux/random.h>
  27 #include <linux/buffer_head.h>
  28 #include <linux/exportfs.h>
  29 #include <linux/vfs.h>
  30 #include <linux/seq_file.h>
  31 #include <linux/mount.h>
  32 #include <linux/log2.h>
  33 #include <linux/quotaops.h>
  34 #include <asm/uaccess.h>
  35 #include "ext2.h"
  36 #include "xattr.h"
  37 #include "acl.h"
  38 #include "xip.h"
  39
  40 static void ext2_sync_super(struct super_block *sb,
  41                             struct ext2_super_block *es, int wait);
  42 static int ext2_remount (struct super_block * sb, int * flags, char * data);
  43 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
  44 static int ext2_sync_fs(struct super_block *sb, int wait);
  45
  46 void ext2_error (struct super_block * sb, const char * function,
  47                  const char * fmt, ...)
  48 {
  49         va_list args;
  50         struct ext2_sb_info *sbi = EXT2_SB(sb);
  51         struct ext2_super_block *es = sbi->s_es;
  52
  53         if (!(sb->s_flags & MS_RDONLY)) {
  54                 spin_lock(&sbi->s_lock);
  55                 sbi->s_mount_state |= EXT2_ERROR_FS;
  56                 es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
  57                 spin_unlock(&sbi->s_lock);
  58                 ext2_sync_super(sb, es, 1);
  59         }
  60
  61         va_start(args, fmt);
  62         printk(KERN_CRIT "EXT2-fs (%s): error: %s: ", sb->s_id, function);
  63         vprintk(fmt, args);
  64         printk("\n");
  65         va_end(args);
  66
  67         if (test_opt(sb, ERRORS_PANIC))
  68                 panic("EXT2-fs: panic from previous error\n");
  69         if (test_opt(sb, ERRORS_RO)) {
  70                 ext2_msg(sb, KERN_CRIT,
  71                              "error: remounting filesystem read-only");
  72                 sb->s_flags |= MS_RDONLY;
  73         }
  74 }
  75
  76 void ext2_msg(struct super_block *sb, const char *prefix,
  77                 const char *fmt, ...)
  78 {
  79         va_list args;
  80
  81         va_start(args, fmt);
  82         printk("%sEXT2-fs (%s): ", prefix, sb->s_id);
  83         vprintk(fmt, args);
  84         printk("\n");
  85         va_end(args);
  86 }
  87
  88 /*
  89  * This must be called with sbi->s_lock held.
  90  */
  91 void ext2_update_dynamic_rev(struct super_block *sb)
  92 {
  93         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
  94
  95         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
  96                 return;
  97
  98         ext2_msg(sb, KERN_WARNING,
  99                      "warning: updating to rev %d because of "
 100                      "new feature flag, running e2fsck is recommended",
 101                      EXT2_DYNAMIC_REV);
 102
 103         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
 104         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
 105         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
 106         /* leave es->s_feature_*compat flags alone */
 107         /* es->s_uuid will be set by e2fsck if empty */
 108
 109         /*
 110          * The rest of the superblock fields should be zero, and if not it
 111          * means they are likely already in use, so leave them alone.  We
 112          * can leave it up to e2fsck to clean up any inconsistencies there.
 113          */
 114 }
 115
 116 static void ext2_put_super (struct super_block * sb)
 117 {
 118         int db_count;
 119         int i;
 120         struct ext2_sb_info *sbi = EXT2_SB(sb);
 121
 122         dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
 123
 124         if (sb->s_dirt)
 125                 ext2_write_super(sb);
 126
 127         ext2_xattr_put_super(sb);
 128         if (!(sb->s_flags & MS_RDONLY)) {
 129                 struct ext2_super_block *es = sbi->s_es;
 130
 131                 spin_lock(&sbi->s_lock);
 132                 es->s_state = cpu_to_le16(sbi->s_mount_state);
 133                 spin_unlock(&sbi->s_lock);
 134                 ext2_sync_super(sb, es, 1);
 135         }
 136         db_count = sbi->s_gdb_count;
 137         for (i = 0; i < db_count; i++)
 138                 if (sbi->s_group_desc[i])
 139                         brelse (sbi->s_group_desc[i]);
 140         kfree(sbi->s_group_desc);
 141         kfree(sbi->s_debts);
 142         percpu_counter_destroy(&sbi->s_freeblocks_counter);
 143         percpu_counter_destroy(&sbi->s_freeinodes_counter);
 144         percpu_counter_destroy(&sbi->s_dirs_counter);
 145         brelse (sbi->s_sbh);
 146         sb->s_fs_info = NULL;
 147         kfree(sbi->s_blockgroup_lock);
 148         kfree(sbi);
 149 }
 150
 151 static struct kmem_cache * ext2_inode_cachep;
 152
 153 static struct inode *ext2_alloc_inode(struct super_block *sb)
 154 {
 155         struct ext2_inode_info *ei;
 156         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
 157         if (!ei)
 158                 return NULL;
 159         ei->i_block_alloc_info = NULL;
 160         ei->vfs_inode.i_version = 1;
 161         return &ei->vfs_inode;
 162 }
 163
 164 static void ext2_destroy_inode(struct inode *inode)
 165 {
 166         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
 167 }
 168
 169 static void init_once(void *foo)
 170 {
 171         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
 172
 173         rwlock_init(&ei->i_meta_lock);
 174 #ifdef CONFIG_EXT2_FS_XATTR
 175         init_rwsem(&ei->xattr_sem);
 176 #endif
 177         mutex_init(&ei->truncate_mutex);
 178         inode_init_once(&ei->vfs_inode);
 179 }
 180
 181 static int init_inodecache(void)
 182 {
 183         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
 184                                              sizeof(struct ext2_inode_info),
 185                                              0, (SLAB_RECLAIM_ACCOUNT|
 186                                                 SLAB_MEM_SPREAD),
 187                                              init_once);
 188         if (ext2_inode_cachep == NULL)
 189                 return -ENOMEM;
 190         return 0;
 191 }
 192
 193 static void destroy_inodecache(void)
 194 {
 195         kmem_cache_destroy(ext2_inode_cachep);
 196 }
 197
 198 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 199 {
 200         struct super_block *sb = vfs->mnt_sb;
 201         struct ext2_sb_info *sbi = EXT2_SB(sb);
 202         struct ext2_super_block *es = sbi->s_es;
 203         unsigned long def_mount_opts;
 204
 205         spin_lock(&sbi->s_lock);
 206         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 207
 208         if (sbi->s_sb_block != 1)
 209                 seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
 210         if (test_opt(sb, MINIX_DF))
 211                 seq_puts(seq, ",minixdf");
 212         if (test_opt(sb, GRPID))
 213                 seq_puts(seq, ",grpid");
 214         if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
 215                 seq_puts(seq, ",nogrpid");
 216         if (sbi->s_resuid != EXT2_DEF_RESUID ||
 217             le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
 218                 seq_printf(seq, ",resuid=%u", sbi->s_resuid);
 219         }
 220         if (sbi->s_resgid != EXT2_DEF_RESGID ||
 221             le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
 222                 seq_printf(seq, ",resgid=%u", sbi->s_resgid);
 223         }
 224         if (test_opt(sb, ERRORS_RO)) {
 225                 int def_errors = le16_to_cpu(es->s_errors);
 226
 227                 if (def_errors == EXT2_ERRORS_PANIC ||
 228                     def_errors == EXT2_ERRORS_CONTINUE) {
 229                         seq_puts(seq, ",errors=remount-ro");
 230                 }
 231         }
 232         if (test_opt(sb, ERRORS_CONT))
 233                 seq_puts(seq, ",errors=continue");
 234         if (test_opt(sb, ERRORS_PANIC))
 235                 seq_puts(seq, ",errors=panic");
 236         if (test_opt(sb, NO_UID32))
 237                 seq_puts(seq, ",nouid32");
 238         if (test_opt(sb, DEBUG))
 239                 seq_puts(seq, ",debug");
 240         if (test_opt(sb, OLDALLOC))
 241                 seq_puts(seq, ",oldalloc");
 242
 243 #ifdef CONFIG_EXT2_FS_XATTR
 244         if (test_opt(sb, XATTR_USER))
 245                 seq_puts(seq, ",user_xattr");
 246         if (!test_opt(sb, XATTR_USER) &&
 247             (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
 248                 seq_puts(seq, ",nouser_xattr");
 249         }
 250 #endif
 251
 252 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 253         if (test_opt(sb, POSIX_ACL))
 254                 seq_puts(seq, ",acl");
 255         if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
 256                 seq_puts(seq, ",noacl");
 257 #endif
 258
 259         if (test_opt(sb, NOBH))
 260                 seq_puts(seq, ",nobh");
 261
 262 #if defined(CONFIG_QUOTA)
 263         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
 264                 seq_puts(seq, ",usrquota");
 265
 266         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
 267                 seq_puts(seq, ",grpquota");
 268 #endif
 269
 270 #if defined(CONFIG_EXT2_FS_XIP)
 271         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
 272                 seq_puts(seq, ",xip");
 273 #endif
 274
 275         if (!test_opt(sb, RESERVATION))
 276                 seq_puts(seq, ",noreservation");
 277
 278         spin_unlock(&sbi->s_lock);
 279         return 0;
 280 }
 281
 282 #ifdef CONFIG_QUOTA
 283 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 284 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 285 #endif
 286
 287 static const struct super_operations ext2_sops = {
 288         .alloc_inode    = ext2_alloc_inode,
 289         .destroy_inode  = ext2_destroy_inode,
 290         .write_inode    = ext2_write_inode,
 291         .evict_inode    = ext2_evict_inode,
 292         .put_super      = ext2_put_super,
 293         .write_super    = ext2_write_super,
 294         .sync_fs        = ext2_sync_fs,
 295         .statfs         = ext2_statfs,
 296         .remount_fs     = ext2_remount,
 297         .show_options   = ext2_show_options,
 298 #ifdef CONFIG_QUOTA
 299         .quota_read     = ext2_quota_read,
 300         .quota_write    = ext2_quota_write,
 301 #endif
 302 };
 303
 304 static struct inode *ext2_nfs_get_inode(struct super_block *sb,
 305                 u64 ino, u32 generation)
 306 {
 307         struct inode *inode;
 308
 309         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
 310                 return ERR_PTR(-ESTALE);
 311         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
 312                 return ERR_PTR(-ESTALE);
 313
 314         /* iget isn't really right if the inode is currently unallocated!!
 315          * ext2_read_inode currently does appropriate checks, but
 316          * it might be "neater" to call ext2_get_inode first and check
 317          * if the inode is valid.....
 318          */
 319         inode = ext2_iget(sb, ino);
 320         if (IS_ERR(inode))
 321                 return ERR_CAST(inode);
 322         if (generation && inode->i_generation != generation) {
 323                 /* we didn't find the right inode.. */
 324                 iput(inode);
 325                 return ERR_PTR(-ESTALE);
 326         }
 327         return inode;
 328 }
 329
 330 static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
 331                 int fh_len, int fh_type)
 332 {
 333         return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
 334                                     ext2_nfs_get_inode);
 335 }
 336
 337 static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
 338                 int fh_len, int fh_type)
 339 {
 340         return generic_fh_to_parent(sb, fid, fh_len, fh_type,
 341                                     ext2_nfs_get_inode);
 342 }
 343
 344 /* Yes, most of these are left as NULL!!
 345  * A NULL value implies the default, which works with ext2-like file
 346  * systems, but can be improved upon.
 347  * Currently only get_parent is required.
 348  */
 349 static const struct export_operations ext2_export_ops = {
 350         .fh_to_dentry = ext2_fh_to_dentry,
 351         .fh_to_parent = ext2_fh_to_parent,
 352         .get_parent = ext2_get_parent,
 353 };
 354
 355 static unsigned long get_sb_block(void **data)
 356 {
 357         unsigned long   sb_block;
 358         char            *options = (char *) *data;
 359
 360         if (!options || strncmp(options, "sb=", 3) != 0)
 361                 return 1;       /* Default location */
 362         options += 3;
 363         sb_block = simple_strtoul(options, &options, 0);
 364         if (*options && *options != ',') {
 365                 printk("EXT2-fs: Invalid sb specification: %s\n",
 366                        (char *) *data);
 367                 return 1;
 368         }
 369         if (*options == ',')
 370                 options++;
 371         *data = (void *) options;
 372         return sb_block;
 373 }
 374
 375 enum {
 376         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 377         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
 378         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
 379         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
 380         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
 381         Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
 382 };
 383
 384 static const match_table_t tokens = {
 385         {Opt_bsd_df, "bsddf"},
 386         {Opt_minix_df, "minixdf"},
 387         {Opt_grpid, "grpid"},
 388         {Opt_grpid, "bsdgroups"},
 389         {Opt_nogrpid, "nogrpid"},
 390         {Opt_nogrpid, "sysvgroups"},
 391         {Opt_resgid, "resgid=%u"},
 392         {Opt_resuid, "resuid=%u"},
 393         {Opt_sb, "sb=%u"},
 394         {Opt_err_cont, "errors=continue"},
 395         {Opt_err_panic, "errors=panic"},
 396         {Opt_err_ro, "errors=remount-ro"},
 397         {Opt_nouid32, "nouid32"},
 398         {Opt_nocheck, "check=none"},
 399         {Opt_nocheck, "nocheck"},
 400         {Opt_debug, "debug"},
 401         {Opt_oldalloc, "oldalloc"},
 402         {Opt_orlov, "orlov"},
 403         {Opt_nobh, "nobh"},
 404         {Opt_user_xattr, "user_xattr"},
 405         {Opt_nouser_xattr, "nouser_xattr"},
 406         {Opt_acl, "acl"},
 407         {Opt_noacl, "noacl"},
 408         {Opt_xip, "xip"},
 409         {Opt_grpquota, "grpquota"},
 410         {Opt_ignore, "noquota"},
 411         {Opt_quota, "quota"},
 412         {Opt_usrquota, "usrquota"},
 413         {Opt_reservation, "reservation"},
 414         {Opt_noreservation, "noreservation"},
 415         {Opt_err, NULL}
 416 };
 417
 418 static int parse_options(char *options, struct super_block *sb)
 419 {
 420         char *p;
 421         struct ext2_sb_info *sbi = EXT2_SB(sb);
 422         substring_t args[MAX_OPT_ARGS];
 423         int option;
 424
 425         if (!options)
 426                 return 1;
 427
 428         while ((p = strsep (&options, ",")) != NULL) {
 429                 int token;
 430                 if (!*p)
 431                         continue;
 432
 433                 token = match_token(p, tokens, args);
 434                 switch (token) {
 435                 case Opt_bsd_df:
 436                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 437                         break;
 438                 case Opt_minix_df:
 439                         set_opt (sbi->s_mount_opt, MINIX_DF);
 440                         break;
 441                 case Opt_grpid:
 442                         set_opt (sbi->s_mount_opt, GRPID);
 443                         break;
 444                 case Opt_nogrpid:
 445                         clear_opt (sbi->s_mount_opt, GRPID);
 446                         break;
 447                 case Opt_resuid:
 448                         if (match_int(&args[0], &option))
 449                                 return 0;
 450                         sbi->s_resuid = option;
 451                         break;
 452                 case Opt_resgid:
 453                         if (match_int(&args[0], &option))
 454                                 return 0;
 455                         sbi->s_resgid = option;
 456                         break;
 457                 case Opt_sb:
 458                         /* handled by get_sb_block() instead of here */
 459                         /* *sb_block = match_int(&args[0]); */
 460                         break;
 461                 case Opt_err_panic:
 462                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 463                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
 464                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
 465                         break;
 466                 case Opt_err_ro:
 467                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 468                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 469                         set_opt (sbi->s_mount_opt, ERRORS_RO);
 470                         break;
 471                 case Opt_err_cont:
 472                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
 473                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 474                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
 475                         break;
 476                 case Opt_nouid32:
 477                         set_opt (sbi->s_mount_opt, NO_UID32);
 478                         break;
 479                 case Opt_nocheck:
 480                         clear_opt (sbi->s_mount_opt, CHECK);
 481                         break;
 482                 case Opt_debug:
 483                         set_opt (sbi->s_mount_opt, DEBUG);
 484                         break;
 485                 case Opt_oldalloc:
 486                         set_opt (sbi->s_mount_opt, OLDALLOC);
 487                         break;
 488                 case Opt_orlov:
 489                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 490                         break;
 491                 case Opt_nobh:
 492                         set_opt (sbi->s_mount_opt, NOBH);
 493                         break;
 494 #ifdef CONFIG_EXT2_FS_XATTR
 495                 case Opt_user_xattr:
 496                         set_opt (sbi->s_mount_opt, XATTR_USER);
 497                         break;
 498                 case Opt_nouser_xattr:
 499                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 500                         break;
 501 #else
 502                 case Opt_user_xattr:
 503                 case Opt_nouser_xattr:
 504                         ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
 505                                 "not supported");
 506                         break;
 507 #endif
 508 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 509                 case Opt_acl:
 510                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 511                         break;
 512                 case Opt_noacl:
 513                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 514                         break;
 515 #else
 516                 case Opt_acl:
 517                 case Opt_noacl:
 518                         ext2_msg(sb, KERN_INFO,
 519                                 "(no)acl options not supported");
 520                         break;
 521 #endif
 522                 case Opt_xip:
 523 #ifdef CONFIG_EXT2_FS_XIP
 524                         set_opt (sbi->s_mount_opt, XIP);
 525 #else
 526                         ext2_msg(sb, KERN_INFO, "xip option not supported");
 527 #endif
 528                         break;
 529
 530 #if defined(CONFIG_QUOTA)
 531                 case Opt_quota:
 532                 case Opt_usrquota:
 533                         set_opt(sbi->s_mount_opt, USRQUOTA);
 534                         break;
 535
 536                 case Opt_grpquota:
 537                         set_opt(sbi->s_mount_opt, GRPQUOTA);
 538                         break;
 539 #else
 540                 case Opt_quota:
 541                 case Opt_usrquota:
 542                 case Opt_grpquota:
 543                         ext2_msg(sb, KERN_INFO,
 544                                 "quota operations not supported");
 545                         break;
 546 #endif
 547
 548                 case Opt_reservation:
 549                         set_opt(sbi->s_mount_opt, RESERVATION);
 550                         ext2_msg(sb, KERN_INFO, "reservations ON");
 551                         break;
 552                 case Opt_noreservation:
 553                         clear_opt(sbi->s_mount_opt, RESERVATION);
 554                         ext2_msg(sb, KERN_INFO, "reservations OFF");
 555                         break;
 556                 case Opt_ignore:
 557                         break;
 558                 default:
 559                         return 0;
 560                 }
 561         }
 562         return 1;
 563 }
 564
 565 static int ext2_setup_super (struct super_block * sb,
 566                               struct ext2_super_block * es,
 567                               int read_only)
 568 {
 569         int res = 0;
 570         struct ext2_sb_info *sbi = EXT2_SB(sb);
 571
 572         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 573                 ext2_msg(sb, KERN_ERR,
 574                         "error: revision level too high, "
 575                         "forcing read-only mode");
 576                 res = MS_RDONLY;
 577         }
 578         if (read_only)
 579                 return res;
 580         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 581                 ext2_msg(sb, KERN_WARNING,
 582                         "warning: mounting unchecked fs, "
 583                         "running e2fsck is recommended");
 584         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 585                 ext2_msg(sb, KERN_WARNING,
 586                         "warning: mounting fs with errors, "
 587                         "running e2fsck is recommended");
 588         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 589                  le16_to_cpu(es->s_mnt_count) >=
 590                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 591                 ext2_msg(sb, KERN_WARNING,
 592                         "warning: maximal mount count reached, "
 593                         "running e2fsck is recommended");
 594         else if (le32_to_cpu(es->s_checkinterval) &&
 595                 (le32_to_cpu(es->s_lastcheck) +
 596                         le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 597                 ext2_msg(sb, KERN_WARNING,
 598                         "warning: checktime reached, "
 599                         "running e2fsck is recommended");
 600         if (!le16_to_cpu(es->s_max_mnt_count))
 601                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 602         le16_add_cpu(&es->s_mnt_count, 1);
 603         if (test_opt (sb, DEBUG))
 604                 ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
 605                         "bpg=%lu, ipg=%lu, mo=%04lx]",
 606                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 607                         sbi->s_frag_size,
 608                         sbi->s_groups_count,
 609                         EXT2_BLOCKS_PER_GROUP(sb),
 610                         EXT2_INODES_PER_GROUP(sb),
 611                         sbi->s_mount_opt);
 612         return res;
 613 }
 614
 615 static int ext2_check_descriptors(struct super_block *sb)
 616 {
 617         int i;
 618         struct ext2_sb_info *sbi = EXT2_SB(sb);
 619
 620         ext2_debug ("Checking group descriptors");
 621
 622         for (i = 0; i < sbi->s_groups_count; i++) {
 623                 struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
 624                 ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
 625                 ext2_fsblk_t last_block;
 626
 627                 if (i == sbi->s_groups_count - 1)
 628                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
 629                 else
 630                         last_block = first_block +
 631                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
 632
 633                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
 634                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
 635                 {
 636                         ext2_error (sb, "ext2_check_descriptors",
 637                                     "Block bitmap for group %d"
 638                                     " not in group (block %lu)!",
 639                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 640                         return 0;
 641                 }
 642                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
 643                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
 644                 {
 645                         ext2_error (sb, "ext2_check_descriptors",
 646                                     "Inode bitmap for group %d"
 647                                     " not in group (block %lu)!",
 648                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 649                         return 0;
 650                 }
 651                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
 652                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
 653                     last_block)
 654                 {
 655                         ext2_error (sb, "ext2_check_descriptors",
 656                                     "Inode table for group %d"
 657                                     " not in group (block %lu)!",
 658                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 659                         return 0;
 660                 }
 661         }
 662         return 1;
 663 }
 664
 665 /*
 666  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 667  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 668  * We need to be 1 filesystem block less than the 2^32 sector limit.
 669  */
 670 static loff_t ext2_max_size(int bits)
 671 {
 672         loff_t res = EXT2_NDIR_BLOCKS;
 673         int meta_blocks;
 674         loff_t upper_limit;
 675
 676         /* This is calculated to be the largest file size for a
 677          * dense, file such that the total number of
 678          * sectors in the file, including data and all indirect blocks,
 679          * does not exceed 2^32 -1
 680          * __u32 i_blocks representing the total number of
 681          * 512 bytes blocks of the file
 682          */
 683         upper_limit = (1LL << 32) - 1;
 684
 685         /* total blocks in file system block size */
 686         upper_limit >>= (bits - 9);
 687
 688
 689         /* indirect blocks */
 690         meta_blocks = 1;
 691         /* double indirect blocks */
 692         meta_blocks += 1 + (1LL << (bits-2));
 693         /* tripple indirect blocks */
 694         meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
 695
 696         upper_limit -= meta_blocks;
 697         upper_limit <<= bits;
 698
 699         res += 1LL << (bits-2);
 700         res += 1LL << (2*(bits-2));
 701         res += 1LL << (3*(bits-2));
 702         res <<= bits;
 703         if (res > upper_limit)
 704                 res = upper_limit;
 705
 706         if (res > MAX_LFS_FILESIZE)
 707                 res = MAX_LFS_FILESIZE;
 708
 709         return res;
 710 }
 711
 712 static unsigned long descriptor_loc(struct super_block *sb,
 713                                     unsigned long logic_sb_block,
 714                                     int nr)
 715 {
 716         struct ext2_sb_info *sbi = EXT2_SB(sb);
 717         unsigned long bg, first_meta_bg;
 718         int has_super = 0;
 719
 720         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 721
 722         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 723             nr < first_meta_bg)
 724                 return (logic_sb_block + nr + 1);
 725         bg = sbi->s_desc_per_block * nr;
 726         if (ext2_bg_has_super(sb, bg))
 727                 has_super = 1;
 728
 729         return ext2_group_first_block_no(sb, bg) + has_super;
 730 }
 731
 732 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 733 {
 734         struct buffer_head * bh;
 735         struct ext2_sb_info * sbi;
 736         struct ext2_super_block * es;
 737         struct inode *root;
 738         unsigned long block;
 739         unsigned long sb_block = get_sb_block(&data);
 740         unsigned long logic_sb_block;
 741         unsigned long offset = 0;
 742         unsigned long def_mount_opts;
 743         long ret = -EINVAL;
 744         int blocksize = BLOCK_SIZE;
 745         int db_count;
 746         int i, j;
 747         __le32 features;
 748         int err;
 749
 750         err = -ENOMEM;
 751         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 752         if (!sbi)
 753                 goto failed_unlock;
 754
 755         sbi->s_blockgroup_lock =
 756                 kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
 757         if (!sbi->s_blockgroup_lock) {
 758                 kfree(sbi);
 759                 goto failed_unlock;
 760         }
 761         sb->s_fs_info = sbi;
 762         sbi->s_sb_block = sb_block;
 763
 764         spin_lock_init(&sbi->s_lock);
 765
 766         /*
 767          * See what the current blocksize for the device is, and
 768          * use that as the blocksize.  Otherwise (or if the blocksize
 769          * is smaller than the default) use the default.
 770          * This is important for devices that have a hardware
 771          * sectorsize that is larger than the default.
 772          */
 773         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 774         if (!blocksize) {
 775                 ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
 776                 goto failed_sbi;
 777         }
 778
 779         /*
 780          * If the superblock doesn't start on a hardware sector boundary,
 781          * calculate the offset.
 782          */
 783         if (blocksize != BLOCK_SIZE) {
 784                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 785                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 786         } else {
 787                 logic_sb_block = sb_block;
 788         }
 789
 790         if (!(bh = sb_bread(sb, logic_sb_block))) {
 791                 ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
 792                 goto failed_sbi;
 793         }
 794         /*
 795          * Note: s_es must be initialized as soon as possible because
 796          *       some ext2 macro-instructions depend on its value
 797          */
 798         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 799         sbi->s_es = es;
 800         sb->s_magic = le16_to_cpu(es->s_magic);
 801
 802         if (sb->s_magic != EXT2_SUPER_MAGIC)
 803                 goto cantfind_ext2;
 804
 805         /* Set defaults before we parse the mount options */
 806         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 807         if (def_mount_opts & EXT2_DEFM_DEBUG)
 808                 set_opt(sbi->s_mount_opt, DEBUG);
 809         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 810                 set_opt(sbi->s_mount_opt, GRPID);
 811         if (def_mount_opts & EXT2_DEFM_UID16)
 812                 set_opt(sbi->s_mount_opt, NO_UID32);
 813 #ifdef CONFIG_EXT2_FS_XATTR
 814         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 815                 set_opt(sbi->s_mount_opt, XATTR_USER);
 816 #endif
 817 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 818         if (def_mount_opts & EXT2_DEFM_ACL)
 819                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 820 #endif
 821
 822         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 823                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 824         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_CONTINUE)
 825                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
 826         else
 827                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 828
 829         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 830         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 831
 832         set_opt(sbi->s_mount_opt, RESERVATION);
 833
 834         if (!parse_options((char *) data, sb))
 835                 goto failed_mount;
 836
 837         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 838                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 839                  MS_POSIXACL : 0);
 840
 841         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
 842                                     EXT2_MOUNT_XIP if not */
 843
 844         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 845             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 846              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 847              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 848                 ext2_msg(sb, KERN_WARNING,
 849                         "warning: feature flags set on rev 0 fs, "
 850                         "running e2fsck is recommended");
 851         /*
 852          * Check feature flags regardless of the revision level, since we
 853          * previously didn't change the revision level when setting the flags,
 854          * so there is a chance incompat flags are set on a rev 0 filesystem.
 855          */
 856         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 857         if (features) {
 858                 ext2_msg(sb, KERN_ERR,  "error: couldn't mount because of "
 859                        "unsupported optional features (%x)",
 860                         le32_to_cpu(features));
 861                 goto failed_mount;
 862         }
 863         if (!(sb->s_flags & MS_RDONLY) &&
 864             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 865                 ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
 866                        "unsupported optional features (%x)",
 867                        le32_to_cpu(features));
 868                 goto failed_mount;
 869         }
 870
 871         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 872
 873         if (ext2_use_xip(sb) && blocksize != PAGE_SIZE) {
 874                 if (!silent)
 875                         ext2_msg(sb, KERN_ERR,
 876                                 "error: unsupported blocksize for xip");
 877                 goto failed_mount;
 878         }
 879
 880         /* If the blocksize doesn't match, re-read the thing.. */
 881         if (sb->s_blocksize != blocksize) {
 882                 brelse(bh);
 883
 884                 if (!sb_set_blocksize(sb, blocksize)) {
 885                         ext2_msg(sb, KERN_ERR, "error: blocksize is too small");
 886                         goto failed_sbi;
 887                 }
 888
 889                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 890                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 891                 bh = sb_bread(sb, logic_sb_block);
 892                 if(!bh) {
 893                         ext2_msg(sb, KERN_ERR, "error: couldn't read"
 894                                 "superblock on 2nd try");
 895                         goto failed_sbi;
 896                 }
 897                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 898                 sbi->s_es = es;
 899                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 900                         ext2_msg(sb, KERN_ERR, "error: magic mismatch");
 901                         goto failed_mount;
 902                 }
 903         }
 904
 905         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 906
 907         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 908                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 909                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 910         } else {
 911                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 912                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 913                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 914                     !is_power_of_2(sbi->s_inode_size) ||
 915                     (sbi->s_inode_size > blocksize)) {
 916                         ext2_msg(sb, KERN_ERR,
 917                                 "error: unsupported inode size: %d",
 918                                 sbi->s_inode_size);
 919                         goto failed_mount;
 920                 }
 921         }
 922
 923         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 924                                    le32_to_cpu(es->s_log_frag_size);
 925         if (sbi->s_frag_size == 0)
 926                 goto cantfind_ext2;
 927         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 928
 929         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 930         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 931         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 932
 933         if (EXT2_INODE_SIZE(sb) == 0)
 934                 goto cantfind_ext2;
 935         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 936         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
 937                 goto cantfind_ext2;
 938         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 939                                         sbi->s_inodes_per_block;
 940         sbi->s_desc_per_block = sb->s_blocksize /
 941                                         sizeof (struct ext2_group_desc);
 942         sbi->s_sbh = bh;
 943         sbi->s_mount_state = le16_to_cpu(es->s_state);
 944         sbi->s_addr_per_block_bits =
 945                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
 946         sbi->s_desc_per_block_bits =
 947                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
 948
 949         if (sb->s_magic != EXT2_SUPER_MAGIC)
 950                 goto cantfind_ext2;
 951
 952         if (sb->s_blocksize != bh->b_size) {
 953                 if (!silent)
 954                         ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
 955                 goto failed_mount;
 956         }
 957
 958         if (sb->s_blocksize != sbi->s_frag_size) {
 959                 ext2_msg(sb, KERN_ERR,
 960                         "error: fragsize %lu != blocksize %lu"
 961                         "(not supported yet)",
 962                         sbi->s_frag_size, sb->s_blocksize);
 963                 goto failed_mount;
 964         }
 965
 966         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 967                 ext2_msg(sb, KERN_ERR,
 968                         "error: #blocks per group too big: %lu",
 969                         sbi->s_blocks_per_group);
 970                 goto failed_mount;
 971         }
 972         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 973                 ext2_msg(sb, KERN_ERR,
 974                         "error: #fragments per group too big: %lu",
 975                         sbi->s_frags_per_group);
 976                 goto failed_mount;
 977         }
 978         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 979                 ext2_msg(sb, KERN_ERR,
 980                         "error: #inodes per group too big: %lu",
 981                         sbi->s_inodes_per_group);
 982                 goto failed_mount;
 983         }
 984
 985         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 986                 goto cantfind_ext2;
 987         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
 988                                 le32_to_cpu(es->s_first_data_block) - 1)
 989                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
 990         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 991                    EXT2_DESC_PER_BLOCK(sb);
 992         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 993         if (sbi->s_group_desc == NULL) {
 994                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
 995                 goto failed_mount;
 996         }
 997         bgl_lock_init(sbi->s_blockgroup_lock);
 998         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
 999         if (!sbi->s_debts) {
1000                 ext2_msg(sb, KERN_ERR, "error: not enough memory");
1001                 goto failed_mount_group_desc;
1002         }
1003         for (i = 0; i < db_count; i++) {
1004                 block = descriptor_loc(sb, logic_sb_block, i);
1005                 sbi->s_group_desc[i] = sb_bread(sb, block);
1006                 if (!sbi->s_group_desc[i]) {
1007                         for (j = 0; j < i; j++)
1008                                 brelse (sbi->s_group_desc[j]);
1009                         ext2_msg(sb, KERN_ERR,
1010                                 "error: unable to read group descriptors");
1011                         goto failed_mount_group_desc;
1012                 }
1013         }
1014         if (!ext2_check_descriptors (sb)) {
1015                 ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
1016                 goto failed_mount2;
1017         }
1018         sbi->s_gdb_count = db_count;
1019         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
1020         spin_lock_init(&sbi->s_next_gen_lock);
1021
1022         /* per fileystem reservation list head & lock */
1023         spin_lock_init(&sbi->s_rsv_window_lock);
1024         sbi->s_rsv_window_root = RB_ROOT;
1025         /*
1026          * Add a single, static dummy reservation to the start of the
1027          * reservation window list --- it gives us a placeholder for
1028          * append-at-start-of-list which makes the allocation logic
1029          * _much_ simpler.
1030          */
1031         sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1032         sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
1033         sbi->s_rsv_window_head.rsv_alloc_hit = 0;
1034         sbi->s_rsv_window_head.rsv_goal_size = 0;
1035         ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
1036
1037         err = percpu_counter_init(&sbi->s_freeblocks_counter,
1038                                 ext2_count_free_blocks(sb));
1039         if (!err) {
1040                 err = percpu_counter_init(&sbi->s_freeinodes_counter,
1041                                 ext2_count_free_inodes(sb));
1042         }
1043         if (!err) {
1044                 err = percpu_counter_init(&sbi->s_dirs_counter,
1045                                 ext2_count_dirs(sb));
1046         }
1047         if (err) {
1048                 ext2_msg(sb, KERN_ERR, "error: insufficient memory");
1049                 goto failed_mount3;
1050         }
1051         /*
1052          * set up enough so that it can read an inode
1053          */
1054         sb->s_op = &ext2_sops;
1055         sb->s_export_op = &ext2_export_ops;
1056         sb->s_xattr = ext2_xattr_handlers;
1057
1058 #ifdef CONFIG_QUOTA
1059         sb->dq_op = &dquot_operations;
1060         sb->s_qcop = &dquot_quotactl_ops;
1061 #endif
1062
1063         root = ext2_iget(sb, EXT2_ROOT_INO);
1064         if (IS_ERR(root)) {
1065                 ret = PTR_ERR(root);
1066                 goto failed_mount3;
1067         }
1068         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
1069                 iput(root);
1070                 ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
1071                 goto failed_mount3;
1072         }
1073
1074         sb->s_root = d_alloc_root(root);
1075         if (!sb->s_root) {
1076                 iput(root);
1077                 ext2_msg(sb, KERN_ERR, "error: get root inode failed");
1078                 ret = -ENOMEM;
1079                 goto failed_mount3;
1080         }
1081         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1082                 ext2_msg(sb, KERN_WARNING,
1083                         "warning: mounting ext3 filesystem as ext2");
1084         if (ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY))
1085                 sb->s_flags |= MS_RDONLY;
1086         ext2_write_super(sb);
1087         return 0;
1088
1089 cantfind_ext2:
1090         if (!silent)
1091                 ext2_msg(sb, KERN_ERR,
1092                         "error: can't find an ext2 filesystem on dev %s.",
1093                         sb->s_id);
1094         goto failed_mount;
1095 failed_mount3:
1096         percpu_counter_destroy(&sbi->s_freeblocks_counter);
1097         percpu_counter_destroy(&sbi->s_freeinodes_counter);
1098         percpu_counter_destroy(&sbi->s_dirs_counter);
1099 failed_mount2:
1100         for (i = 0; i < db_count; i++)
1101                 brelse(sbi->s_group_desc[i]);
1102 failed_mount_group_desc:
1103         kfree(sbi->s_group_desc);
1104         kfree(sbi->s_debts);
1105 failed_mount:
1106         brelse(bh);
1107 failed_sbi:
1108         sb->s_fs_info = NULL;
1109         kfree(sbi->s_blockgroup_lock);
1110         kfree(sbi);
1111 failed_unlock:
1112         return ret;
1113 }
1114
1115 static void ext2_clear_super_error(struct super_block *sb)
1116 {
1117         struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
1118
1119         if (buffer_write_io_error(sbh)) {
1120                 /*
1121                  * Oh, dear.  A previous attempt to write the
1122                  * superblock failed.  This could happen because the
1123                  * USB device was yanked out.  Or it could happen to
1124                  * be a transient write error and maybe the block will
1125                  * be remapped.  Nothing we can do but to retry the
1126                  * write and hope for the best.
1127                  */
1128                 ext2_msg(sb, KERN_ERR,
1129                        "previous I/O error to superblock detected\n");
1130                 clear_buffer_write_io_error(sbh);
1131                 set_buffer_uptodate(sbh);
1132         }
1133 }
1134
1135 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
1136                             int wait)
1137 {
1138         ext2_clear_super_error(sb);
1139         spin_lock(&EXT2_SB(sb)->s_lock);
1140         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1141         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1142         es->s_wtime = cpu_to_le32(get_seconds());
1143         /* unlock before we do IO */
1144         spin_unlock(&EXT2_SB(sb)->s_lock);
1145         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1146         if (wait)
1147                 sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1148         sb->s_dirt = 0;
1149 }
1150
1151 /*
1152  * In the second extended file system, it is not necessary to
1153  * write the super block since we use a mapping of the
1154  * disk super block in a buffer.
1155  *
1156  * However, this function is still used to set the fs valid
1157  * flags to 0.  We need to set this flag to 0 since the fs
1158  * may have been checked while mounted and e2fsck may have
1159  * set s_state to EXT2_VALID_FS after some corrections.
1160  */
1161 static int ext2_sync_fs(struct super_block *sb, int wait)
1162 {
1163         struct ext2_sb_info *sbi = EXT2_SB(sb);
1164         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
1165
1166         spin_lock(&sbi->s_lock);
1167         if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
1168                 ext2_debug("setting valid to 0\n");
1169                 es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
1170         }
1171         spin_unlock(&sbi->s_lock);
1172         ext2_sync_super(sb, es, wait);
1173         return 0;
1174 }
1175
1176
1177 void ext2_write_super(struct super_block *sb)
1178 {
1179         if (!(sb->s_flags & MS_RDONLY))
1180                 ext2_sync_fs(sb, 1);
1181         else
1182                 sb->s_dirt = 0;
1183 }
1184
1185 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1186 {
1187         struct ext2_sb_info * sbi = EXT2_SB(sb);
1188         struct ext2_super_block * es;
1189         unsigned long old_mount_opt = sbi->s_mount_opt;
1190         struct ext2_mount_options old_opts;
1191         unsigned long old_sb_flags;
1192         int err;
1193
1194         spin_lock(&sbi->s_lock);
1195
1196         /* Store the old options */
1197         old_sb_flags = sb->s_flags;
1198         old_opts.s_mount_opt = sbi->s_mount_opt;
1199         old_opts.s_resuid = sbi->s_resuid;
1200         old_opts.s_resgid = sbi->s_resgid;
1201
1202         /*
1203          * Allow the "check" option to be passed as a remount option.
1204          */
1205         if (!parse_options(data, sb)) {
1206                 err = -EINVAL;
1207                 goto restore_opts;
1208         }
1209
1210         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1211                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1212
1213         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1214                                     EXT2_MOUNT_XIP if not */
1215
1216         if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1217                 ext2_msg(sb, KERN_WARNING,
1218                         "warning: unsupported blocksize for xip");
1219                 err = -EINVAL;
1220                 goto restore_opts;
1221         }
1222
1223         es = sbi->s_es;
1224         if ((sbi->s_mount_opt ^ old_mount_opt) & EXT2_MOUNT_XIP) {
1225                 ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
1226                          "xip flag with busy inodes while remounting");
1227                 sbi->s_mount_opt &= ~EXT2_MOUNT_XIP;
1228                 sbi->s_mount_opt |= old_mount_opt & EXT2_MOUNT_XIP;
1229         }
1230         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
1231                 spin_unlock(&sbi->s_lock);
1232                 return 0;
1233         }
1234         if (*flags & MS_RDONLY) {
1235                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1236                     !(sbi->s_mount_state & EXT2_VALID_FS)) {
1237                         spin_unlock(&sbi->s_lock);
1238                         return 0;
1239                 }
1240
1241                 /*
1242                  * OK, we are remounting a valid rw partition rdonly, so set
1243                  * the rdonly flag and then mark the partition as valid again.
1244                  */
1245                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1246                 es->s_mtime = cpu_to_le32(get_seconds());
1247                 spin_unlock(&sbi->s_lock);
1248
1249                 err = dquot_suspend(sb, -1);
1250                 if (err < 0) {
1251                         spin_lock(&sbi->s_lock);
1252                         goto restore_opts;
1253                 }
1254
1255                 ext2_sync_super(sb, es, 1);
1256         } else {
1257                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1258                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1259                 if (ret) {
1260                         ext2_msg(sb, KERN_WARNING,
1261                                 "warning: couldn't remount RDWR because of "
1262                                 "unsupported optional features (%x).",
1263                                 le32_to_cpu(ret));
1264                         err = -EROFS;
1265                         goto restore_opts;
1266                 }
1267                 /*
1268                  * Mounting a RDONLY partition read-write, so reread and
1269                  * store the current valid flag.  (It may have been changed
1270                  * by e2fsck since we originally mounted the partition.)
1271                  */
1272                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1273                 if (!ext2_setup_super (sb, es, 0))
1274                         sb->s_flags &= ~MS_RDONLY;
1275                 spin_unlock(&sbi->s_lock);
1276
1277                 ext2_write_super(sb);
1278
1279                 dquot_resume(sb, -1);
1280         }
1281
1282         return 0;
1283 restore_opts:
1284         sbi->s_mount_opt = old_opts.s_mount_opt;
1285         sbi->s_resuid = old_opts.s_resuid;
1286         sbi->s_resgid = old_opts.s_resgid;
1287         sb->s_flags = old_sb_flags;
1288         spin_unlock(&sbi->s_lock);
1289         return err;
1290 }
1291
1292 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1293 {
1294         struct super_block *sb = dentry->d_sb;
1295         struct ext2_sb_info *sbi = EXT2_SB(sb);
1296         struct ext2_super_block *es = sbi->s_es;
1297         u64 fsid;
1298
1299         spin_lock(&sbi->s_lock);
1300
1301         if (test_opt (sb, MINIX_DF))
1302                 sbi->s_overhead_last = 0;
1303         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1304                 unsigned long i, overhead = 0;
1305                 smp_rmb();
1306
1307                 /*
1308                  * Compute the overhead (FS structures). This is constant
1309                  * for a given filesystem unless the number of block groups
1310                  * changes so we cache the previous value until it does.
1311                  */
1312
1313                 /*
1314                  * All of the blocks before first_data_block are
1315                  * overhead
1316                  */
1317                 overhead = le32_to_cpu(es->s_first_data_block);
1318
1319                 /*
1320                  * Add the overhead attributed to the superblock and
1321                  * block group descriptors.  If the sparse superblocks
1322                  * feature is turned on, then not all groups have this.
1323                  */
1324                 for (i = 0; i < sbi->s_groups_count; i++)
1325                         overhead += ext2_bg_has_super(sb, i) +
1326                                 ext2_bg_num_gdb(sb, i);
1327
1328                 /*
1329                  * Every block group has an inode bitmap, a block
1330                  * bitmap, and an inode table.
1331                  */
1332                 overhead += (sbi->s_groups_count *
1333                              (2 + sbi->s_itb_per_group));
1334                 sbi->s_overhead_last = overhead;
1335                 smp_wmb();
1336                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1337         }
1338
1339         buf->f_type = EXT2_SUPER_MAGIC;
1340         buf->f_bsize = sb->s_blocksize;
1341         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1342         buf->f_bfree = ext2_count_free_blocks(sb);
1343         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1344         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1345         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1346                 buf->f_bavail = 0;
1347         buf->f_files = le32_to_cpu(es->s_inodes_count);
1348         buf->f_ffree = ext2_count_free_inodes(sb);
1349         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1350         buf->f_namelen = EXT2_NAME_LEN;
1351         fsid = le64_to_cpup((void *)es->s_uuid) ^
1352                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1353         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1354         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1355         spin_unlock(&sbi->s_lock);
1356         return 0;
1357 }
1358
1359 static struct dentry *ext2_mount(struct file_system_type *fs_type,
1360         int flags, const char *dev_name, void *data)
1361 {
1362         return mount_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
1363 }
1364
1365 #ifdef CONFIG_QUOTA
1366
1367 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1368  * acquiring the locks... As quota files are never truncated and quota code
1369  * itself serializes the operations (and noone else should touch the files)
1370  * we don't have to be afraid of races */
1371 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1372                                size_t len, loff_t off)
1373 {
1374         struct inode *inode = sb_dqopt(sb)->files[type];
1375         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1376         int err = 0;
1377         int offset = off & (sb->s_blocksize - 1);
1378         int tocopy;
1379         size_t toread;
1380         struct buffer_head tmp_bh;
1381         struct buffer_head *bh;
1382         loff_t i_size = i_size_read(inode);
1383
1384         if (off > i_size)
1385                 return 0;
1386         if (off+len > i_size)
1387                 len = i_size-off;
1388         toread = len;
1389         while (toread > 0) {
1390                 tocopy = sb->s_blocksize - offset < toread ?
1391                                 sb->s_blocksize - offset : toread;
1392
1393                 tmp_bh.b_state = 0;
1394                 tmp_bh.b_size = sb->s_blocksize;
1395                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1396                 if (err < 0)
1397                         return err;
1398                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1399                         memset(data, 0, tocopy);
1400                 else {
1401                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1402                         if (!bh)
1403                                 return -EIO;
1404                         memcpy(data, bh->b_data+offset, tocopy);
1405                         brelse(bh);
1406                 }
1407                 offset = 0;
1408                 toread -= tocopy;
1409                 data += tocopy;
1410                 blk++;
1411         }
1412         return len;
1413 }
1414
1415 /* Write to quotafile */
1416 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1417                                 const char *data, size_t len, loff_t off)
1418 {
1419         struct inode *inode = sb_dqopt(sb)->files[type];
1420         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1421         int err = 0;
1422         int offset = off & (sb->s_blocksize - 1);
1423         int tocopy;
1424         size_t towrite = len;
1425         struct buffer_head tmp_bh;
1426         struct buffer_head *bh;
1427
1428         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1429         while (towrite > 0) {
1430                 tocopy = sb->s_blocksize - offset < towrite ?
1431                                 sb->s_blocksize - offset : towrite;
1432
1433                 tmp_bh.b_state = 0;
1434                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1435                 if (err < 0)
1436                         goto out;
1437                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1438                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1439                 else
1440                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1441                 if (!bh) {
1442                         err = -EIO;
1443                         goto out;
1444                 }
1445                 lock_buffer(bh);
1446                 memcpy(bh->b_data+offset, data, tocopy);
1447                 flush_dcache_page(bh->b_page);
1448                 set_buffer_uptodate(bh);
1449                 mark_buffer_dirty(bh);
1450                 unlock_buffer(bh);
1451                 brelse(bh);
1452                 offset = 0;
1453                 towrite -= tocopy;
1454                 data += tocopy;
1455                 blk++;
1456         }
1457 out:
1458         if (len == towrite) {
1459                 mutex_unlock(&inode->i_mutex);
1460                 return err;
1461         }
1462         if (inode->i_size < off+len-towrite)
1463                 i_size_write(inode, off+len-towrite);
1464         inode->i_version++;
1465         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1466         mark_inode_dirty(inode);
1467         mutex_unlock(&inode->i_mutex);
1468         return len - towrite;
1469 }
1470
1471 #endif
1472
1473 static struct file_system_type ext2_fs_type = {
1474         .owner          = THIS_MODULE,
1475         .name           = "ext2",
1476         .mount          = ext2_mount,
1477         .kill_sb        = kill_block_super,
1478         .fs_flags       = FS_REQUIRES_DEV,
1479 };
1480
1481 static int __init init_ext2_fs(void)
1482 {
1483         int err = init_ext2_xattr();
1484         if (err)
1485                 return err;
1486         err = init_inodecache();
1487         if (err)
1488                 goto out1;
1489         err = register_filesystem(&ext2_fs_type);
1490         if (err)
1491                 goto out;
1492         return 0;
1493 out:
1494         destroy_inodecache();
1495 out1:
1496         exit_ext2_xattr();
1497         return err;
1498 }
1499
1500 static void __exit exit_ext2_fs(void)
1501 {
1502         unregister_filesystem(&ext2_fs_type);
1503         destroy_inodecache();
1504         exit_ext2_xattr();
1505 }
1506
1507 module_init(init_ext2_fs)
1508 module_exit(exit_ext2_fs)