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/smp_lock.h>
  30 #include <linux/vfs.h>
  31 #include <linux/seq_file.h>
  32 #include <linux/mount.h>
  33 #include <asm/uaccess.h>
  34 #include "ext2.h"
  35 #include "xattr.h"
  36 #include "acl.h"
  37 #include "xip.h"
  38
  39 static void ext2_sync_super(struct super_block *sb,
  40                             struct ext2_super_block *es);
  41 static int ext2_remount (struct super_block * sb, int * flags, char * data);
  42 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
  43
  44 void ext2_error (struct super_block * sb, const char * function,
  45                  const char * fmt, ...)
  46 {
  47         va_list args;
  48         struct ext2_sb_info *sbi = EXT2_SB(sb);
  49         struct ext2_super_block *es = sbi->s_es;
  50
  51         if (!(sb->s_flags & MS_RDONLY)) {
  52                 sbi->s_mount_state |= EXT2_ERROR_FS;
  53                 es->s_state =
  54                         cpu_to_le16(le16_to_cpu(es->s_state) | EXT2_ERROR_FS);
  55                 ext2_sync_super(sb, es);
  56         }
  57
  58         va_start(args, fmt);
  59         printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
  60         vprintk(fmt, args);
  61         printk("\n");
  62         va_end(args);
  63
  64         if (test_opt(sb, ERRORS_PANIC))
  65                 panic("EXT2-fs panic from previous error\n");
  66         if (test_opt(sb, ERRORS_RO)) {
  67                 printk("Remounting filesystem read-only\n");
  68                 sb->s_flags |= MS_RDONLY;
  69         }
  70 }
  71
  72 void ext2_warning (struct super_block * sb, const char * function,
  73                    const char * fmt, ...)
  74 {
  75         va_list args;
  76
  77         va_start(args, fmt);
  78         printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
  79                sb->s_id, function);
  80         vprintk(fmt, args);
  81         printk("\n");
  82         va_end(args);
  83 }
  84
  85 void ext2_update_dynamic_rev(struct super_block *sb)
  86 {
  87         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
  88
  89         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
  90                 return;
  91
  92         ext2_warning(sb, __FUNCTION__,
  93                      "updating to rev %d because of new feature flag, "
  94                      "running e2fsck is recommended",
  95                      EXT2_DYNAMIC_REV);
  96
  97         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
  98         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
  99         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
 100         /* leave es->s_feature_*compat flags alone */
 101         /* es->s_uuid will be set by e2fsck if empty */
 102
 103         /*
 104          * The rest of the superblock fields should be zero, and if not it
 105          * means they are likely already in use, so leave them alone.  We
 106          * can leave it up to e2fsck to clean up any inconsistencies there.
 107          */
 108 }
 109
 110 static void ext2_put_super (struct super_block * sb)
 111 {
 112         int db_count;
 113         int i;
 114         struct ext2_sb_info *sbi = EXT2_SB(sb);
 115
 116         ext2_xattr_put_super(sb);
 117         if (!(sb->s_flags & MS_RDONLY)) {
 118                 struct ext2_super_block *es = sbi->s_es;
 119
 120                 es->s_state = cpu_to_le16(sbi->s_mount_state);
 121                 ext2_sync_super(sb, es);
 122         }
 123         db_count = sbi->s_gdb_count;
 124         for (i = 0; i < db_count; i++)
 125                 if (sbi->s_group_desc[i])
 126                         brelse (sbi->s_group_desc[i]);
 127         kfree(sbi->s_group_desc);
 128         kfree(sbi->s_debts);
 129         percpu_counter_destroy(&sbi->s_freeblocks_counter);
 130         percpu_counter_destroy(&sbi->s_freeinodes_counter);
 131         percpu_counter_destroy(&sbi->s_dirs_counter);
 132         brelse (sbi->s_sbh);
 133         sb->s_fs_info = NULL;
 134         kfree(sbi);
 135
 136         return;
 137 }
 138
 139 static struct kmem_cache * ext2_inode_cachep;
 140
 141 static struct inode *ext2_alloc_inode(struct super_block *sb)
 142 {
 143         struct ext2_inode_info *ei;
 144         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
 145         if (!ei)
 146                 return NULL;
 147 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 148         ei->i_acl = EXT2_ACL_NOT_CACHED;
 149         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 150 #endif
 151         ei->vfs_inode.i_version = 1;
 152         return &ei->vfs_inode;
 153 }
 154
 155 static void ext2_destroy_inode(struct inode *inode)
 156 {
 157         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
 158 }
 159
 160 static void init_once(struct kmem_cache * cachep, void *foo)
 161 {
 162         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
 163
 164         rwlock_init(&ei->i_meta_lock);
 165 #ifdef CONFIG_EXT2_FS_XATTR
 166         init_rwsem(&ei->xattr_sem);
 167 #endif
 168         inode_init_once(&ei->vfs_inode);
 169 }
 170
 171 static int init_inodecache(void)
 172 {
 173         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
 174                                              sizeof(struct ext2_inode_info),
 175                                              0, (SLAB_RECLAIM_ACCOUNT|
 176                                                 SLAB_MEM_SPREAD),
 177                                              init_once);
 178         if (ext2_inode_cachep == NULL)
 179                 return -ENOMEM;
 180         return 0;
 181 }
 182
 183 static void destroy_inodecache(void)
 184 {
 185         kmem_cache_destroy(ext2_inode_cachep);
 186 }
 187
 188 static void ext2_clear_inode(struct inode *inode)
 189 {
 190 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 191         struct ext2_inode_info *ei = EXT2_I(inode);
 192
 193         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
 194                 posix_acl_release(ei->i_acl);
 195                 ei->i_acl = EXT2_ACL_NOT_CACHED;
 196         }
 197         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
 198                 posix_acl_release(ei->i_default_acl);
 199                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 200         }
 201 #endif
 202 }
 203
 204 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 205 {
 206         struct super_block *sb = vfs->mnt_sb;
 207         struct ext2_sb_info *sbi = EXT2_SB(sb);
 208         struct ext2_super_block *es = sbi->s_es;
 209         unsigned long def_mount_opts;
 210
 211         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 212
 213         if (sbi->s_sb_block != 1)
 214                 seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
 215         if (test_opt(sb, MINIX_DF))
 216                 seq_puts(seq, ",minixdf");
 217         if (test_opt(sb, GRPID))
 218                 seq_puts(seq, ",grpid");
 219         if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
 220                 seq_puts(seq, ",nogrpid");
 221         if (sbi->s_resuid != EXT2_DEF_RESUID ||
 222             le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
 223                 seq_printf(seq, ",resuid=%u", sbi->s_resuid);
 224         }
 225         if (sbi->s_resgid != EXT2_DEF_RESGID ||
 226             le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
 227                 seq_printf(seq, ",resgid=%u", sbi->s_resgid);
 228         }
 229         if (test_opt(sb, ERRORS_CONT)) {
 230                 int def_errors = le16_to_cpu(es->s_errors);
 231
 232                 if (def_errors == EXT2_ERRORS_PANIC ||
 233                     def_errors == EXT2_ERRORS_RO) {
 234                         seq_puts(seq, ",errors=continue");
 235                 }
 236         }
 237         if (test_opt(sb, ERRORS_RO))
 238                 seq_puts(seq, ",errors=remount-ro");
 239         if (test_opt(sb, ERRORS_PANIC))
 240                 seq_puts(seq, ",errors=panic");
 241         if (test_opt(sb, NO_UID32))
 242                 seq_puts(seq, ",nouid32");
 243         if (test_opt(sb, DEBUG))
 244                 seq_puts(seq, ",debug");
 245         if (test_opt(sb, OLDALLOC))
 246                 seq_puts(seq, ",oldalloc");
 247
 248 #ifdef CONFIG_EXT2_FS_XATTR
 249         if (test_opt(sb, XATTR_USER))
 250                 seq_puts(seq, ",user_xattr");
 251         if (!test_opt(sb, XATTR_USER) &&
 252             (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
 253                 seq_puts(seq, ",nouser_xattr");
 254         }
 255 #endif
 256
 257 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 258         if (test_opt(sb, POSIX_ACL))
 259                 seq_puts(seq, ",acl");
 260         if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
 261                 seq_puts(seq, ",noacl");
 262 #endif
 263
 264         if (test_opt(sb, NOBH))
 265                 seq_puts(seq, ",nobh");
 266
 267 #if defined(CONFIG_QUOTA)
 268         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
 269                 seq_puts(seq, ",usrquota");
 270
 271         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
 272                 seq_puts(seq, ",grpquota");
 273 #endif
 274
 275 #if defined(CONFIG_EXT2_FS_XIP)
 276         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
 277                 seq_puts(seq, ",xip");
 278 #endif
 279
 280         return 0;
 281 }
 282
 283 #ifdef CONFIG_QUOTA
 284 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 285 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 286 #endif
 287
 288 static const struct super_operations ext2_sops = {
 289         .alloc_inode    = ext2_alloc_inode,
 290         .destroy_inode  = ext2_destroy_inode,
 291         .read_inode     = ext2_read_inode,
 292         .write_inode    = ext2_write_inode,
 293         .put_inode      = ext2_put_inode,
 294         .delete_inode   = ext2_delete_inode,
 295         .put_super      = ext2_put_super,
 296         .write_super    = ext2_write_super,
 297         .statfs         = ext2_statfs,
 298         .remount_fs     = ext2_remount,
 299         .clear_inode    = ext2_clear_inode,
 300         .show_options   = ext2_show_options,
 301 #ifdef CONFIG_QUOTA
 302         .quota_read     = ext2_quota_read,
 303         .quota_write    = ext2_quota_write,
 304 #endif
 305 };
 306
 307 static struct dentry *ext2_get_dentry(struct super_block *sb, void *vobjp)
 308 {
 309         __u32 *objp = vobjp;
 310         unsigned long ino = objp[0];
 311         __u32 generation = objp[1];
 312         struct inode *inode;
 313         struct dentry *result;
 314
 315         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
 316                 return ERR_PTR(-ESTALE);
 317         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
 318                 return ERR_PTR(-ESTALE);
 319
 320         /* iget isn't really right if the inode is currently unallocated!!
 321          * ext2_read_inode currently does appropriate checks, but
 322          * it might be "neater" to call ext2_get_inode first and check
 323          * if the inode is valid.....
 324          */
 325         inode = iget(sb, ino);
 326         if (inode == NULL)
 327                 return ERR_PTR(-ENOMEM);
 328         if (is_bad_inode(inode) ||
 329             (generation && inode->i_generation != generation)) {
 330                 /* we didn't find the right inode.. */
 331                 iput(inode);
 332                 return ERR_PTR(-ESTALE);
 333         }
 334         /* now to find a dentry.
 335          * If possible, get a well-connected one
 336          */
 337         result = d_alloc_anon(inode);
 338         if (!result) {
 339                 iput(inode);
 340                 return ERR_PTR(-ENOMEM);
 341         }
 342         return result;
 343 }
 344
 345 /* Yes, most of these are left as NULL!!
 346  * A NULL value implies the default, which works with ext2-like file
 347  * systems, but can be improved upon.
 348  * Currently only get_parent is required.
 349  */
 350 static struct export_operations ext2_export_ops = {
 351         .get_parent = ext2_get_parent,
 352         .get_dentry = ext2_get_dentry,
 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
 382 };
 383
 384 static 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_err, NULL}
 414 };
 415
 416 static int parse_options (char * options,
 417                           struct ext2_sb_info *sbi)
 418 {
 419         char * p;
 420         substring_t args[MAX_OPT_ARGS];
 421         int option;
 422
 423         if (!options)
 424                 return 1;
 425
 426         while ((p = strsep (&options, ",")) != NULL) {
 427                 int token;
 428                 if (!*p)
 429                         continue;
 430
 431                 token = match_token(p, tokens, args);
 432                 switch (token) {
 433                 case Opt_bsd_df:
 434                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 435                         break;
 436                 case Opt_minix_df:
 437                         set_opt (sbi->s_mount_opt, MINIX_DF);
 438                         break;
 439                 case Opt_grpid:
 440                         set_opt (sbi->s_mount_opt, GRPID);
 441                         break;
 442                 case Opt_nogrpid:
 443                         clear_opt (sbi->s_mount_opt, GRPID);
 444                         break;
 445                 case Opt_resuid:
 446                         if (match_int(&args[0], &option))
 447                                 return 0;
 448                         sbi->s_resuid = option;
 449                         break;
 450                 case Opt_resgid:
 451                         if (match_int(&args[0], &option))
 452                                 return 0;
 453                         sbi->s_resgid = option;
 454                         break;
 455                 case Opt_sb:
 456                         /* handled by get_sb_block() instead of here */
 457                         /* *sb_block = match_int(&args[0]); */
 458                         break;
 459                 case Opt_err_panic:
 460                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 461                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
 462                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
 463                         break;
 464                 case Opt_err_ro:
 465                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 466                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 467                         set_opt (sbi->s_mount_opt, ERRORS_RO);
 468                         break;
 469                 case Opt_err_cont:
 470                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
 471                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 472                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
 473                         break;
 474                 case Opt_nouid32:
 475                         set_opt (sbi->s_mount_opt, NO_UID32);
 476                         break;
 477                 case Opt_nocheck:
 478                         clear_opt (sbi->s_mount_opt, CHECK);
 479                         break;
 480                 case Opt_debug:
 481                         set_opt (sbi->s_mount_opt, DEBUG);
 482                         break;
 483                 case Opt_oldalloc:
 484                         set_opt (sbi->s_mount_opt, OLDALLOC);
 485                         break;
 486                 case Opt_orlov:
 487                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 488                         break;
 489                 case Opt_nobh:
 490                         set_opt (sbi->s_mount_opt, NOBH);
 491                         break;
 492 #ifdef CONFIG_EXT2_FS_XATTR
 493                 case Opt_user_xattr:
 494                         set_opt (sbi->s_mount_opt, XATTR_USER);
 495                         break;
 496                 case Opt_nouser_xattr:
 497                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 498                         break;
 499 #else
 500                 case Opt_user_xattr:
 501                 case Opt_nouser_xattr:
 502                         printk("EXT2 (no)user_xattr options not supported\n");
 503                         break;
 504 #endif
 505 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 506                 case Opt_acl:
 507                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 508                         break;
 509                 case Opt_noacl:
 510                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 511                         break;
 512 #else
 513                 case Opt_acl:
 514                 case Opt_noacl:
 515                         printk("EXT2 (no)acl options not supported\n");
 516                         break;
 517 #endif
 518                 case Opt_xip:
 519 #ifdef CONFIG_EXT2_FS_XIP
 520                         set_opt (sbi->s_mount_opt, XIP);
 521 #else
 522                         printk("EXT2 xip option not supported\n");
 523 #endif
 524                         break;
 525
 526 #if defined(CONFIG_QUOTA)
 527                 case Opt_quota:
 528                 case Opt_usrquota:
 529                         set_opt(sbi->s_mount_opt, USRQUOTA);
 530                         break;
 531
 532                 case Opt_grpquota:
 533                         set_opt(sbi->s_mount_opt, GRPQUOTA);
 534                         break;
 535 #else
 536                 case Opt_quota:
 537                 case Opt_usrquota:
 538                 case Opt_grpquota:
 539                         printk(KERN_ERR
 540                                 "EXT2-fs: quota operations not supported.\n");
 541
 542                         break;
 543 #endif
 544
 545                 case Opt_ignore:
 546                         break;
 547                 default:
 548                         return 0;
 549                 }
 550         }
 551         return 1;
 552 }
 553
 554 static int ext2_setup_super (struct super_block * sb,
 555                               struct ext2_super_block * es,
 556                               int read_only)
 557 {
 558         int res = 0;
 559         struct ext2_sb_info *sbi = EXT2_SB(sb);
 560
 561         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 562                 printk ("EXT2-fs warning: revision level too high, "
 563                         "forcing read-only mode\n");
 564                 res = MS_RDONLY;
 565         }
 566         if (read_only)
 567                 return res;
 568         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 569                 printk ("EXT2-fs warning: mounting unchecked fs, "
 570                         "running e2fsck is recommended\n");
 571         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 572                 printk ("EXT2-fs warning: mounting fs with errors, "
 573                         "running e2fsck is recommended\n");
 574         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 575                  le16_to_cpu(es->s_mnt_count) >=
 576                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 577                 printk ("EXT2-fs warning: maximal mount count reached, "
 578                         "running e2fsck is recommended\n");
 579         else if (le32_to_cpu(es->s_checkinterval) &&
 580                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 581                 printk ("EXT2-fs warning: checktime reached, "
 582                         "running e2fsck is recommended\n");
 583         if (!le16_to_cpu(es->s_max_mnt_count))
 584                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 585         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 586         ext2_write_super(sb);
 587         if (test_opt (sb, DEBUG))
 588                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 589                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 590                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 591                         sbi->s_frag_size,
 592                         sbi->s_groups_count,
 593                         EXT2_BLOCKS_PER_GROUP(sb),
 594                         EXT2_INODES_PER_GROUP(sb),
 595                         sbi->s_mount_opt);
 596         return res;
 597 }
 598
 599 static int ext2_check_descriptors (struct super_block * sb)
 600 {
 601         int i;
 602         int desc_block = 0;
 603         struct ext2_sb_info *sbi = EXT2_SB(sb);
 604         unsigned long first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 605         unsigned long last_block;
 606         struct ext2_group_desc * gdp = NULL;
 607
 608         ext2_debug ("Checking group descriptors");
 609
 610         for (i = 0; i < sbi->s_groups_count; i++)
 611         {
 612                 if (i == sbi->s_groups_count - 1)
 613                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
 614                 else
 615                         last_block = first_block +
 616                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
 617
 618                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 619                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
 620                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
 621                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
 622                 {
 623                         ext2_error (sb, "ext2_check_descriptors",
 624                                     "Block bitmap for group %d"
 625                                     " not in group (block %lu)!",
 626                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 627                         return 0;
 628                 }
 629                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
 630                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
 631                 {
 632                         ext2_error (sb, "ext2_check_descriptors",
 633                                     "Inode bitmap for group %d"
 634                                     " not in group (block %lu)!",
 635                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 636                         return 0;
 637                 }
 638                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
 639                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
 640                     last_block)
 641                 {
 642                         ext2_error (sb, "ext2_check_descriptors",
 643                                     "Inode table for group %d"
 644                                     " not in group (block %lu)!",
 645                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 646                         return 0;
 647                 }
 648                 first_block += EXT2_BLOCKS_PER_GROUP(sb);
 649                 gdp++;
 650         }
 651         return 1;
 652 }
 653
 654 /*
 655  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 656  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 657  * We need to be 1 filesystem block less than the 2^32 sector limit.
 658  */
 659 static loff_t ext2_max_size(int bits)
 660 {
 661         loff_t res = EXT2_NDIR_BLOCKS;
 662         /* This constant is calculated to be the largest file size for a
 663          * dense, 4k-blocksize file such that the total number of
 664          * sectors in the file, including data and all indirect blocks,
 665          * does not exceed 2^32. */
 666         const loff_t upper_limit = 0x1ff7fffd000LL;
 667
 668         res += 1LL << (bits-2);
 669         res += 1LL << (2*(bits-2));
 670         res += 1LL << (3*(bits-2));
 671         res <<= bits;
 672         if (res > upper_limit)
 673                 res = upper_limit;
 674         return res;
 675 }
 676
 677 static unsigned long descriptor_loc(struct super_block *sb,
 678                                     unsigned long logic_sb_block,
 679                                     int nr)
 680 {
 681         struct ext2_sb_info *sbi = EXT2_SB(sb);
 682         unsigned long bg, first_data_block, first_meta_bg;
 683         int has_super = 0;
 684
 685         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 686         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 687
 688         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 689             nr < first_meta_bg)
 690                 return (logic_sb_block + nr + 1);
 691         bg = sbi->s_desc_per_block * nr;
 692         if (ext2_bg_has_super(sb, bg))
 693                 has_super = 1;
 694         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 695 }
 696
 697 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 698 {
 699         struct buffer_head * bh;
 700         struct ext2_sb_info * sbi;
 701         struct ext2_super_block * es;
 702         struct inode *root;
 703         unsigned long block;
 704         unsigned long sb_block = get_sb_block(&data);
 705         unsigned long logic_sb_block;
 706         unsigned long offset = 0;
 707         unsigned long def_mount_opts;
 708         int blocksize = BLOCK_SIZE;
 709         int db_count;
 710         int i, j;
 711         __le32 features;
 712         int err;
 713
 714         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 715         if (!sbi)
 716                 return -ENOMEM;
 717         sb->s_fs_info = sbi;
 718         sbi->s_sb_block = sb_block;
 719
 720         /*
 721          * See what the current blocksize for the device is, and
 722          * use that as the blocksize.  Otherwise (or if the blocksize
 723          * is smaller than the default) use the default.
 724          * This is important for devices that have a hardware
 725          * sectorsize that is larger than the default.
 726          */
 727         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 728         if (!blocksize) {
 729                 printk ("EXT2-fs: unable to set blocksize\n");
 730                 goto failed_sbi;
 731         }
 732
 733         /*
 734          * If the superblock doesn't start on a hardware sector boundary,
 735          * calculate the offset.
 736          */
 737         if (blocksize != BLOCK_SIZE) {
 738                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 739                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 740         } else {
 741                 logic_sb_block = sb_block;
 742         }
 743
 744         if (!(bh = sb_bread(sb, logic_sb_block))) {
 745                 printk ("EXT2-fs: unable to read superblock\n");
 746                 goto failed_sbi;
 747         }
 748         /*
 749          * Note: s_es must be initialized as soon as possible because
 750          *       some ext2 macro-instructions depend on its value
 751          */
 752         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 753         sbi->s_es = es;
 754         sb->s_magic = le16_to_cpu(es->s_magic);
 755
 756         if (sb->s_magic != EXT2_SUPER_MAGIC)
 757                 goto cantfind_ext2;
 758
 759         /* Set defaults before we parse the mount options */
 760         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 761         if (def_mount_opts & EXT2_DEFM_DEBUG)
 762                 set_opt(sbi->s_mount_opt, DEBUG);
 763         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 764                 set_opt(sbi->s_mount_opt, GRPID);
 765         if (def_mount_opts & EXT2_DEFM_UID16)
 766                 set_opt(sbi->s_mount_opt, NO_UID32);
 767 #ifdef CONFIG_EXT2_FS_XATTR
 768         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 769                 set_opt(sbi->s_mount_opt, XATTR_USER);
 770 #endif
 771 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 772         if (def_mount_opts & EXT2_DEFM_ACL)
 773                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 774 #endif
 775
 776         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 777                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 778         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
 779                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 780         else
 781                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
 782
 783         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 784         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 785
 786         if (!parse_options ((char *) data, sbi))
 787                 goto failed_mount;
 788
 789         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 790                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 791                  MS_POSIXACL : 0);
 792
 793         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
 794                                     EXT2_MOUNT_XIP if not */
 795
 796         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 797             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 798              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 799              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 800                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 801                        "running e2fsck is recommended\n");
 802         /*
 803          * Check feature flags regardless of the revision level, since we
 804          * previously didn't change the revision level when setting the flags,
 805          * so there is a chance incompat flags are set on a rev 0 filesystem.
 806          */
 807         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 808         if (features) {
 809                 printk("EXT2-fs: %s: couldn't mount because of "
 810                        "unsupported optional features (%x).\n",
 811                        sb->s_id, le32_to_cpu(features));
 812                 goto failed_mount;
 813         }
 814         if (!(sb->s_flags & MS_RDONLY) &&
 815             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 816                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 817                        "unsupported optional features (%x).\n",
 818                        sb->s_id, le32_to_cpu(features));
 819                 goto failed_mount;
 820         }
 821
 822         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 823
 824         if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
 825                                   (sb->s_blocksize != blocksize))) {
 826                 if (!silent)
 827                         printk("XIP: Unsupported blocksize\n");
 828                 goto failed_mount;
 829         }
 830
 831         /* If the blocksize doesn't match, re-read the thing.. */
 832         if (sb->s_blocksize != blocksize) {
 833                 brelse(bh);
 834
 835                 if (!sb_set_blocksize(sb, blocksize)) {
 836                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 837                         goto failed_sbi;
 838                 }
 839
 840                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 841                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 842                 bh = sb_bread(sb, logic_sb_block);
 843                 if(!bh) {
 844                         printk("EXT2-fs: Couldn't read superblock on "
 845                                "2nd try.\n");
 846                         goto failed_sbi;
 847                 }
 848                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 849                 sbi->s_es = es;
 850                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 851                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 852                         goto failed_mount;
 853                 }
 854         }
 855
 856         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 857
 858         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 859                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 860                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 861         } else {
 862                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 863                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 864                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 865                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
 866                     (sbi->s_inode_size > blocksize)) {
 867                         printk ("EXT2-fs: unsupported inode size: %d\n",
 868                                 sbi->s_inode_size);
 869                         goto failed_mount;
 870                 }
 871         }
 872
 873         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 874                                    le32_to_cpu(es->s_log_frag_size);
 875         if (sbi->s_frag_size == 0)
 876                 goto cantfind_ext2;
 877         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 878
 879         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 880         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 881         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 882
 883         if (EXT2_INODE_SIZE(sb) == 0)
 884                 goto cantfind_ext2;
 885         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 886         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
 887                 goto cantfind_ext2;
 888         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 889                                         sbi->s_inodes_per_block;
 890         sbi->s_desc_per_block = sb->s_blocksize /
 891                                         sizeof (struct ext2_group_desc);
 892         sbi->s_sbh = bh;
 893         sbi->s_mount_state = le16_to_cpu(es->s_state);
 894         sbi->s_addr_per_block_bits =
 895                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
 896         sbi->s_desc_per_block_bits =
 897                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
 898
 899         if (sb->s_magic != EXT2_SUPER_MAGIC)
 900                 goto cantfind_ext2;
 901
 902         if (sb->s_blocksize != bh->b_size) {
 903                 if (!silent)
 904                         printk ("VFS: Unsupported blocksize on dev "
 905                                 "%s.\n", sb->s_id);
 906                 goto failed_mount;
 907         }
 908
 909         if (sb->s_blocksize != sbi->s_frag_size) {
 910                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 911                         sbi->s_frag_size, sb->s_blocksize);
 912                 goto failed_mount;
 913         }
 914
 915         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 916                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 917                         sbi->s_blocks_per_group);
 918                 goto failed_mount;
 919         }
 920         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 921                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 922                         sbi->s_frags_per_group);
 923                 goto failed_mount;
 924         }
 925         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 926                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 927                         sbi->s_inodes_per_group);
 928                 goto failed_mount;
 929         }
 930
 931         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 932                 goto cantfind_ext2;
 933         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
 934                                 le32_to_cpu(es->s_first_data_block) - 1)
 935                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
 936         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 937                    EXT2_DESC_PER_BLOCK(sb);
 938         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 939         if (sbi->s_group_desc == NULL) {
 940                 printk ("EXT2-fs: not enough memory\n");
 941                 goto failed_mount;
 942         }
 943         bgl_lock_init(&sbi->s_blockgroup_lock);
 944         sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
 945         if (!sbi->s_debts) {
 946                 printk ("EXT2-fs: not enough memory\n");
 947                 goto failed_mount_group_desc;
 948         }
 949         for (i = 0; i < db_count; i++) {
 950                 block = descriptor_loc(sb, logic_sb_block, i);
 951                 sbi->s_group_desc[i] = sb_bread(sb, block);
 952                 if (!sbi->s_group_desc[i]) {
 953                         for (j = 0; j < i; j++)
 954                                 brelse (sbi->s_group_desc[j]);
 955                         printk ("EXT2-fs: unable to read group descriptors\n");
 956                         goto failed_mount_group_desc;
 957                 }
 958         }
 959         if (!ext2_check_descriptors (sb)) {
 960                 printk ("EXT2-fs: group descriptors corrupted!\n");
 961                 goto failed_mount2;
 962         }
 963         sbi->s_gdb_count = db_count;
 964         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 965         spin_lock_init(&sbi->s_next_gen_lock);
 966
 967         err = percpu_counter_init(&sbi->s_freeblocks_counter,
 968                                 ext2_count_free_blocks(sb));
 969         if (!err) {
 970                 err = percpu_counter_init(&sbi->s_freeinodes_counter,
 971                                 ext2_count_free_inodes(sb));
 972         }
 973         if (!err) {
 974                 err = percpu_counter_init(&sbi->s_dirs_counter,
 975                                 ext2_count_dirs(sb));
 976         }
 977         if (err) {
 978                 printk(KERN_ERR "EXT2-fs: insufficient memory\n");
 979                 goto failed_mount3;
 980         }
 981         /*
 982          * set up enough so that it can read an inode
 983          */
 984         sb->s_op = &ext2_sops;
 985         sb->s_export_op = &ext2_export_ops;
 986         sb->s_xattr = ext2_xattr_handlers;
 987         root = iget(sb, EXT2_ROOT_INO);
 988         sb->s_root = d_alloc_root(root);
 989         if (!sb->s_root) {
 990                 iput(root);
 991                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 992                 goto failed_mount3;
 993         }
 994         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 995                 dput(sb->s_root);
 996                 sb->s_root = NULL;
 997                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 998                 goto failed_mount3;
 999         }
1000         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
1001                 ext2_warning(sb, __FUNCTION__,
1002                         "mounting ext3 filesystem as ext2");
1003         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
1004         return 0;
1005
1006 cantfind_ext2:
1007         if (!silent)
1008                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
1009                        sb->s_id);
1010         goto failed_mount;
1011 failed_mount3:
1012         percpu_counter_destroy(&sbi->s_freeblocks_counter);
1013         percpu_counter_destroy(&sbi->s_freeinodes_counter);
1014         percpu_counter_destroy(&sbi->s_dirs_counter);
1015 failed_mount2:
1016         for (i = 0; i < db_count; i++)
1017                 brelse(sbi->s_group_desc[i]);
1018 failed_mount_group_desc:
1019         kfree(sbi->s_group_desc);
1020         kfree(sbi->s_debts);
1021 failed_mount:
1022         brelse(bh);
1023 failed_sbi:
1024         sb->s_fs_info = NULL;
1025         kfree(sbi);
1026         return -EINVAL;
1027 }
1028
1029 static void ext2_commit_super (struct super_block * sb,
1030                                struct ext2_super_block * es)
1031 {
1032         es->s_wtime = cpu_to_le32(get_seconds());
1033         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1034         sb->s_dirt = 0;
1035 }
1036
1037 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
1038 {
1039         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1040         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1041         es->s_wtime = cpu_to_le32(get_seconds());
1042         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
1043         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
1044         sb->s_dirt = 0;
1045 }
1046
1047 /*
1048  * In the second extended file system, it is not necessary to
1049  * write the super block since we use a mapping of the
1050  * disk super block in a buffer.
1051  *
1052  * However, this function is still used to set the fs valid
1053  * flags to 0.  We need to set this flag to 0 since the fs
1054  * may have been checked while mounted and e2fsck may have
1055  * set s_state to EXT2_VALID_FS after some corrections.
1056  */
1057
1058 void ext2_write_super (struct super_block * sb)
1059 {
1060         struct ext2_super_block * es;
1061         lock_kernel();
1062         if (!(sb->s_flags & MS_RDONLY)) {
1063                 es = EXT2_SB(sb)->s_es;
1064
1065                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
1066                         ext2_debug ("setting valid to 0\n");
1067                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
1068                                                   ~EXT2_VALID_FS);
1069                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1070                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1071                         es->s_mtime = cpu_to_le32(get_seconds());
1072                         ext2_sync_super(sb, es);
1073                 } else
1074                         ext2_commit_super (sb, es);
1075         }
1076         sb->s_dirt = 0;
1077         unlock_kernel();
1078 }
1079
1080 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1081 {
1082         struct ext2_sb_info * sbi = EXT2_SB(sb);
1083         struct ext2_super_block * es;
1084         unsigned long old_mount_opt = sbi->s_mount_opt;
1085         struct ext2_mount_options old_opts;
1086         unsigned long old_sb_flags;
1087         int err;
1088
1089         /* Store the old options */
1090         old_sb_flags = sb->s_flags;
1091         old_opts.s_mount_opt = sbi->s_mount_opt;
1092         old_opts.s_resuid = sbi->s_resuid;
1093         old_opts.s_resgid = sbi->s_resgid;
1094
1095         /*
1096          * Allow the "check" option to be passed as a remount option.
1097          */
1098         if (!parse_options (data, sbi)) {
1099                 err = -EINVAL;
1100                 goto restore_opts;
1101         }
1102
1103         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1104                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1105
1106         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
1107                                     EXT2_MOUNT_XIP if not */
1108
1109         if ((ext2_use_xip(sb)) && (sb->s_blocksize != PAGE_SIZE)) {
1110                 printk("XIP: Unsupported blocksize\n");
1111                 err = -EINVAL;
1112                 goto restore_opts;
1113         }
1114
1115         es = sbi->s_es;
1116         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1117             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1118             invalidate_inodes(sb))
1119                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1120                              "xip remain in cache (no functional problem)");
1121         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1122                 return 0;
1123         if (*flags & MS_RDONLY) {
1124                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1125                     !(sbi->s_mount_state & EXT2_VALID_FS))
1126                         return 0;
1127                 /*
1128                  * OK, we are remounting a valid rw partition rdonly, so set
1129                  * the rdonly flag and then mark the partition as valid again.
1130                  */
1131                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1132                 es->s_mtime = cpu_to_le32(get_seconds());
1133         } else {
1134                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1135                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1136                 if (ret) {
1137                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1138                                "unsupported optional features (%x).\n",
1139                                sb->s_id, le32_to_cpu(ret));
1140                         err = -EROFS;
1141                         goto restore_opts;
1142                 }
1143                 /*
1144                  * Mounting a RDONLY partition read-write, so reread and
1145                  * store the current valid flag.  (It may have been changed
1146                  * by e2fsck since we originally mounted the partition.)
1147                  */
1148                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1149                 if (!ext2_setup_super (sb, es, 0))
1150                         sb->s_flags &= ~MS_RDONLY;
1151         }
1152         ext2_sync_super(sb, es);
1153         return 0;
1154 restore_opts:
1155         sbi->s_mount_opt = old_opts.s_mount_opt;
1156         sbi->s_resuid = old_opts.s_resuid;
1157         sbi->s_resgid = old_opts.s_resgid;
1158         sb->s_flags = old_sb_flags;
1159         return err;
1160 }
1161
1162 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1163 {
1164         struct super_block *sb = dentry->d_sb;
1165         struct ext2_sb_info *sbi = EXT2_SB(sb);
1166         struct ext2_super_block *es = sbi->s_es;
1167         u64 fsid;
1168
1169         if (test_opt (sb, MINIX_DF))
1170                 sbi->s_overhead_last = 0;
1171         else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
1172                 unsigned long i, overhead = 0;
1173                 smp_rmb();
1174
1175                 /*
1176                  * Compute the overhead (FS structures). This is constant
1177                  * for a given filesystem unless the number of block groups
1178                  * changes so we cache the previous value until it does.
1179                  */
1180
1181                 /*
1182                  * All of the blocks before first_data_block are
1183                  * overhead
1184                  */
1185                 overhead = le32_to_cpu(es->s_first_data_block);
1186
1187                 /*
1188                  * Add the overhead attributed to the superblock and
1189                  * block group descriptors.  If the sparse superblocks
1190                  * feature is turned on, then not all groups have this.
1191                  */
1192                 for (i = 0; i < sbi->s_groups_count; i++)
1193                         overhead += ext2_bg_has_super(sb, i) +
1194                                 ext2_bg_num_gdb(sb, i);
1195
1196                 /*
1197                  * Every block group has an inode bitmap, a block
1198                  * bitmap, and an inode table.
1199                  */
1200                 overhead += (sbi->s_groups_count *
1201                              (2 + sbi->s_itb_per_group));
1202                 sbi->s_overhead_last = overhead;
1203                 smp_wmb();
1204                 sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
1205         }
1206
1207         buf->f_type = EXT2_SUPER_MAGIC;
1208         buf->f_bsize = sb->s_blocksize;
1209         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
1210         buf->f_bfree = ext2_count_free_blocks(sb);
1211         es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
1212         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1213         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1214                 buf->f_bavail = 0;
1215         buf->f_files = le32_to_cpu(es->s_inodes_count);
1216         buf->f_ffree = ext2_count_free_inodes(sb);
1217         es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
1218         buf->f_namelen = EXT2_NAME_LEN;
1219         fsid = le64_to_cpup((void *)es->s_uuid) ^
1220                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1221         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1222         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1223         return 0;
1224 }
1225
1226 static int ext2_get_sb(struct file_system_type *fs_type,
1227         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1228 {
1229         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1230 }
1231
1232 #ifdef CONFIG_QUOTA
1233
1234 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1235  * acquiring the locks... As quota files are never truncated and quota code
1236  * itself serializes the operations (and noone else should touch the files)
1237  * we don't have to be afraid of races */
1238 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1239                                size_t len, loff_t off)
1240 {
1241         struct inode *inode = sb_dqopt(sb)->files[type];
1242         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1243         int err = 0;
1244         int offset = off & (sb->s_blocksize - 1);
1245         int tocopy;
1246         size_t toread;
1247         struct buffer_head tmp_bh;
1248         struct buffer_head *bh;
1249         loff_t i_size = i_size_read(inode);
1250
1251         if (off > i_size)
1252                 return 0;
1253         if (off+len > i_size)
1254                 len = i_size-off;
1255         toread = len;
1256         while (toread > 0) {
1257                 tocopy = sb->s_blocksize - offset < toread ?
1258                                 sb->s_blocksize - offset : toread;
1259
1260                 tmp_bh.b_state = 0;
1261                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1262                 if (err)
1263                         return err;
1264                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1265                         memset(data, 0, tocopy);
1266                 else {
1267                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1268                         if (!bh)
1269                                 return -EIO;
1270                         memcpy(data, bh->b_data+offset, tocopy);
1271                         brelse(bh);
1272                 }
1273                 offset = 0;
1274                 toread -= tocopy;
1275                 data += tocopy;
1276                 blk++;
1277         }
1278         return len;
1279 }
1280
1281 /* Write to quotafile */
1282 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1283                                 const char *data, size_t len, loff_t off)
1284 {
1285         struct inode *inode = sb_dqopt(sb)->files[type];
1286         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1287         int err = 0;
1288         int offset = off & (sb->s_blocksize - 1);
1289         int tocopy;
1290         size_t towrite = len;
1291         struct buffer_head tmp_bh;
1292         struct buffer_head *bh;
1293
1294         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1295         while (towrite > 0) {
1296                 tocopy = sb->s_blocksize - offset < towrite ?
1297                                 sb->s_blocksize - offset : towrite;
1298
1299                 tmp_bh.b_state = 0;
1300                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1301                 if (err)
1302                         goto out;
1303                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1304                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1305                 else
1306                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1307                 if (!bh) {
1308                         err = -EIO;
1309                         goto out;
1310                 }
1311                 lock_buffer(bh);
1312                 memcpy(bh->b_data+offset, data, tocopy);
1313                 flush_dcache_page(bh->b_page);
1314                 set_buffer_uptodate(bh);
1315                 mark_buffer_dirty(bh);
1316                 unlock_buffer(bh);
1317                 brelse(bh);
1318                 offset = 0;
1319                 towrite -= tocopy;
1320                 data += tocopy;
1321                 blk++;
1322         }
1323 out:
1324         if (len == towrite)
1325                 return err;
1326         if (inode->i_size < off+len-towrite)
1327                 i_size_write(inode, off+len-towrite);
1328         inode->i_version++;
1329         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1330         mark_inode_dirty(inode);
1331         mutex_unlock(&inode->i_mutex);
1332         return len - towrite;
1333 }
1334
1335 #endif
1336
1337 static struct file_system_type ext2_fs_type = {
1338         .owner          = THIS_MODULE,
1339         .name           = "ext2",
1340         .get_sb         = ext2_get_sb,
1341         .kill_sb        = kill_block_super,
1342         .fs_flags       = FS_REQUIRES_DEV,
1343 };
1344
1345 static int __init init_ext2_fs(void)
1346 {
1347         int err = init_ext2_xattr();
1348         if (err)
1349                 return err;
1350         err = init_inodecache();
1351         if (err)
1352                 goto out1;
1353         err = register_filesystem(&ext2_fs_type);
1354         if (err)
1355                 goto out;
1356         return 0;
1357 out:
1358         destroy_inodecache();
1359 out1:
1360         exit_ext2_xattr();
1361         return err;
1362 }
1363
1364 static void __exit exit_ext2_fs(void)
1365 {
1366         unregister_filesystem(&ext2_fs_type);
1367         destroy_inodecache();
1368         exit_ext2_xattr();
1369 }
1370
1371 module_init(init_ext2_fs)
1372 module_exit(exit_ext2_fs)