SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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/smp_lock.h>
  29 #include <linux/vfs.h>
  30 #include <linux/seq_file.h>
  31 #include <linux/mount.h>
  32 #include <asm/uaccess.h>
  33 #include "ext2.h"
  34 #include "xattr.h"
  35 #include "acl.h"
  36 #include "xip.h"
  37
  38 static void ext2_sync_super(struct super_block *sb,
  39                             struct ext2_super_block *es);
  40 static int ext2_remount (struct super_block * sb, int * flags, char * data);
  41 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
  42
  43 void ext2_error (struct super_block * sb, const char * function,
  44                  const char * fmt, ...)
  45 {
  46         va_list args;
  47         struct ext2_sb_info *sbi = EXT2_SB(sb);
  48         struct ext2_super_block *es = sbi->s_es;
  49
  50         if (!(sb->s_flags & MS_RDONLY)) {
  51                 sbi->s_mount_state |= EXT2_ERROR_FS;
  52                 es->s_state =
  53                         cpu_to_le16(le16_to_cpu(es->s_state) | EXT2_ERROR_FS);
  54                 ext2_sync_super(sb, es);
  55         }
  56
  57         va_start(args, fmt);
  58         printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
  59         vprintk(fmt, args);
  60         printk("\n");
  61         va_end(args);
  62
  63         if (test_opt(sb, ERRORS_PANIC))
  64                 panic("EXT2-fs panic from previous error\n");
  65         if (test_opt(sb, ERRORS_RO)) {
  66                 printk("Remounting filesystem read-only\n");
  67                 sb->s_flags |= MS_RDONLY;
  68         }
  69 }
  70
  71 void ext2_warning (struct super_block * sb, const char * function,
  72                    const char * fmt, ...)
  73 {
  74         va_list args;
  75
  76         va_start(args, fmt);
  77         printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
  78                sb->s_id, function);
  79         vprintk(fmt, args);
  80         printk("\n");
  81         va_end(args);
  82 }
  83
  84 void ext2_update_dynamic_rev(struct super_block *sb)
  85 {
  86         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
  87
  88         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
  89                 return;
  90
  91         ext2_warning(sb, __FUNCTION__,
  92                      "updating to rev %d because of new feature flag, "
  93                      "running e2fsck is recommended",
  94                      EXT2_DYNAMIC_REV);
  95
  96         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
  97         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
  98         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
  99         /* leave es->s_feature_*compat flags alone */
 100         /* es->s_uuid will be set by e2fsck if empty */
 101
 102         /*
 103          * The rest of the superblock fields should be zero, and if not it
 104          * means they are likely already in use, so leave them alone.  We
 105          * can leave it up to e2fsck to clean up any inconsistencies there.
 106          */
 107 }
 108
 109 static void ext2_put_super (struct super_block * sb)
 110 {
 111         int db_count;
 112         int i;
 113         struct ext2_sb_info *sbi = EXT2_SB(sb);
 114
 115         ext2_xattr_put_super(sb);
 116         if (!(sb->s_flags & MS_RDONLY)) {
 117                 struct ext2_super_block *es = sbi->s_es;
 118
 119                 es->s_state = cpu_to_le16(sbi->s_mount_state);
 120                 ext2_sync_super(sb, es);
 121         }
 122         db_count = sbi->s_gdb_count;
 123         for (i = 0; i < db_count; i++)
 124                 if (sbi->s_group_desc[i])
 125                         brelse (sbi->s_group_desc[i]);
 126         kfree(sbi->s_group_desc);
 127         kfree(sbi->s_debts);
 128         percpu_counter_destroy(&sbi->s_freeblocks_counter);
 129         percpu_counter_destroy(&sbi->s_freeinodes_counter);
 130         percpu_counter_destroy(&sbi->s_dirs_counter);
 131         brelse (sbi->s_sbh);
 132         sb->s_fs_info = NULL;
 133         kfree(sbi);
 134
 135         return;
 136 }
 137
 138 static struct kmem_cache * ext2_inode_cachep;
 139
 140 static struct inode *ext2_alloc_inode(struct super_block *sb)
 141 {
 142         struct ext2_inode_info *ei;
 143         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
 144         if (!ei)
 145                 return NULL;
 146 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 147         ei->i_acl = EXT2_ACL_NOT_CACHED;
 148         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 149 #endif
 150         ei->vfs_inode.i_version = 1;
 151         return &ei->vfs_inode;
 152 }
 153
 154 static void ext2_destroy_inode(struct inode *inode)
 155 {
 156         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
 157 }
 158
 159 static void init_once(void * foo, struct kmem_cache * cachep, unsigned long flags)
 160 {
 161         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
 162
 163         if (flags & SLAB_CTOR_CONSTRUCTOR) {
 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
 172 static int init_inodecache(void)
 173 {
 174         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
 175                                              sizeof(struct ext2_inode_info),
 176                                              0, (SLAB_RECLAIM_ACCOUNT|
 177                                                 SLAB_MEM_SPREAD),
 178                                              init_once, NULL);
 179         if (ext2_inode_cachep == NULL)
 180                 return -ENOMEM;
 181         return 0;
 182 }
 183
 184 static void destroy_inodecache(void)
 185 {
 186         kmem_cache_destroy(ext2_inode_cachep);
 187 }
 188
 189 static void ext2_clear_inode(struct inode *inode)
 190 {
 191 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 192         struct ext2_inode_info *ei = EXT2_I(inode);
 193
 194         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
 195                 posix_acl_release(ei->i_acl);
 196                 ei->i_acl = EXT2_ACL_NOT_CACHED;
 197         }
 198         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
 199                 posix_acl_release(ei->i_default_acl);
 200                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 201         }
 202 #endif
 203 }
 204
 205 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 206 {
 207         struct ext2_sb_info *sbi = EXT2_SB(vfs->mnt_sb);
 208
 209         if (sbi->s_mount_opt & EXT2_MOUNT_GRPID)
 210                 seq_puts(seq, ",grpid");
 211
 212 #if defined(CONFIG_QUOTA)
 213         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
 214                 seq_puts(seq, ",usrquota");
 215
 216         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
 217                 seq_puts(seq, ",grpquota");
 218 #endif
 219
 220 #if defined(CONFIG_EXT2_FS_XIP)
 221         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
 222                 seq_puts(seq, ",xip");
 223 #endif
 224
 225         return 0;
 226 }
 227
 228 #ifdef CONFIG_QUOTA
 229 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 230 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 231 #endif
 232
 233 static const struct super_operations ext2_sops = {
 234         .alloc_inode    = ext2_alloc_inode,
 235         .destroy_inode  = ext2_destroy_inode,
 236         .read_inode     = ext2_read_inode,
 237         .write_inode    = ext2_write_inode,
 238         .put_inode      = ext2_put_inode,
 239         .delete_inode   = ext2_delete_inode,
 240         .put_super      = ext2_put_super,
 241         .write_super    = ext2_write_super,
 242         .statfs         = ext2_statfs,
 243         .remount_fs     = ext2_remount,
 244         .clear_inode    = ext2_clear_inode,
 245         .show_options   = ext2_show_options,
 246 #ifdef CONFIG_QUOTA
 247         .quota_read     = ext2_quota_read,
 248         .quota_write    = ext2_quota_write,
 249 #endif
 250 };
 251
 252 static struct dentry *ext2_get_dentry(struct super_block *sb, void *vobjp)
 253 {
 254         __u32 *objp = vobjp;
 255         unsigned long ino = objp[0];
 256         __u32 generation = objp[1];
 257         struct inode *inode;
 258         struct dentry *result;
 259
 260         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
 261                 return ERR_PTR(-ESTALE);
 262         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
 263                 return ERR_PTR(-ESTALE);
 264
 265         /* iget isn't really right if the inode is currently unallocated!!
 266          * ext2_read_inode currently does appropriate checks, but
 267          * it might be "neater" to call ext2_get_inode first and check
 268          * if the inode is valid.....
 269          */
 270         inode = iget(sb, ino);
 271         if (inode == NULL)
 272                 return ERR_PTR(-ENOMEM);
 273         if (is_bad_inode(inode) ||
 274             (generation && inode->i_generation != generation)) {
 275                 /* we didn't find the right inode.. */
 276                 iput(inode);
 277                 return ERR_PTR(-ESTALE);
 278         }
 279         /* now to find a dentry.
 280          * If possible, get a well-connected one
 281          */
 282         result = d_alloc_anon(inode);
 283         if (!result) {
 284                 iput(inode);
 285                 return ERR_PTR(-ENOMEM);
 286         }
 287         return result;
 288 }
 289
 290 /* Yes, most of these are left as NULL!!
 291  * A NULL value implies the default, which works with ext2-like file
 292  * systems, but can be improved upon.
 293  * Currently only get_parent is required.
 294  */
 295 static struct export_operations ext2_export_ops = {
 296         .get_parent = ext2_get_parent,
 297         .get_dentry = ext2_get_dentry,
 298 };
 299
 300 static unsigned long get_sb_block(void **data)
 301 {
 302         unsigned long   sb_block;
 303         char            *options = (char *) *data;
 304
 305         if (!options || strncmp(options, "sb=", 3) != 0)
 306                 return 1;       /* Default location */
 307         options += 3;
 308         sb_block = simple_strtoul(options, &options, 0);
 309         if (*options && *options != ',') {
 310                 printk("EXT2-fs: Invalid sb specification: %s\n",
 311                        (char *) *data);
 312                 return 1;
 313         }
 314         if (*options == ',')
 315                 options++;
 316         *data = (void *) options;
 317         return sb_block;
 318 }
 319
 320 enum {
 321         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 322         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
 323         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
 324         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
 325         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
 326         Opt_usrquota, Opt_grpquota
 327 };
 328
 329 static match_table_t tokens = {
 330         {Opt_bsd_df, "bsddf"},
 331         {Opt_minix_df, "minixdf"},
 332         {Opt_grpid, "grpid"},
 333         {Opt_grpid, "bsdgroups"},
 334         {Opt_nogrpid, "nogrpid"},
 335         {Opt_nogrpid, "sysvgroups"},
 336         {Opt_resgid, "resgid=%u"},
 337         {Opt_resuid, "resuid=%u"},
 338         {Opt_sb, "sb=%u"},
 339         {Opt_err_cont, "errors=continue"},
 340         {Opt_err_panic, "errors=panic"},
 341         {Opt_err_ro, "errors=remount-ro"},
 342         {Opt_nouid32, "nouid32"},
 343         {Opt_nocheck, "check=none"},
 344         {Opt_nocheck, "nocheck"},
 345         {Opt_debug, "debug"},
 346         {Opt_oldalloc, "oldalloc"},
 347         {Opt_orlov, "orlov"},
 348         {Opt_nobh, "nobh"},
 349         {Opt_user_xattr, "user_xattr"},
 350         {Opt_nouser_xattr, "nouser_xattr"},
 351         {Opt_acl, "acl"},
 352         {Opt_noacl, "noacl"},
 353         {Opt_xip, "xip"},
 354         {Opt_grpquota, "grpquota"},
 355         {Opt_ignore, "noquota"},
 356         {Opt_quota, "quota"},
 357         {Opt_usrquota, "usrquota"},
 358         {Opt_err, NULL}
 359 };
 360
 361 static int parse_options (char * options,
 362                           struct ext2_sb_info *sbi)
 363 {
 364         char * p;
 365         substring_t args[MAX_OPT_ARGS];
 366         int option;
 367
 368         if (!options)
 369                 return 1;
 370
 371         while ((p = strsep (&options, ",")) != NULL) {
 372                 int token;
 373                 if (!*p)
 374                         continue;
 375
 376                 token = match_token(p, tokens, args);
 377                 switch (token) {
 378                 case Opt_bsd_df:
 379                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 380                         break;
 381                 case Opt_minix_df:
 382                         set_opt (sbi->s_mount_opt, MINIX_DF);
 383                         break;
 384                 case Opt_grpid:
 385                         set_opt (sbi->s_mount_opt, GRPID);
 386                         break;
 387                 case Opt_nogrpid:
 388                         clear_opt (sbi->s_mount_opt, GRPID);
 389                         break;
 390                 case Opt_resuid:
 391                         if (match_int(&args[0], &option))
 392                                 return 0;
 393                         sbi->s_resuid = option;
 394                         break;
 395                 case Opt_resgid:
 396                         if (match_int(&args[0], &option))
 397                                 return 0;
 398                         sbi->s_resgid = option;
 399                         break;
 400                 case Opt_sb:
 401                         /* handled by get_sb_block() instead of here */
 402                         /* *sb_block = match_int(&args[0]); */
 403                         break;
 404                 case Opt_err_panic:
 405                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 406                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
 407                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
 408                         break;
 409                 case Opt_err_ro:
 410                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 411                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 412                         set_opt (sbi->s_mount_opt, ERRORS_RO);
 413                         break;
 414                 case Opt_err_cont:
 415                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
 416                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 417                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
 418                         break;
 419                 case Opt_nouid32:
 420                         set_opt (sbi->s_mount_opt, NO_UID32);
 421                         break;
 422                 case Opt_nocheck:
 423                         clear_opt (sbi->s_mount_opt, CHECK);
 424                         break;
 425                 case Opt_debug:
 426                         set_opt (sbi->s_mount_opt, DEBUG);
 427                         break;
 428                 case Opt_oldalloc:
 429                         set_opt (sbi->s_mount_opt, OLDALLOC);
 430                         break;
 431                 case Opt_orlov:
 432                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 433                         break;
 434                 case Opt_nobh:
 435                         set_opt (sbi->s_mount_opt, NOBH);
 436                         break;
 437 #ifdef CONFIG_EXT2_FS_XATTR
 438                 case Opt_user_xattr:
 439                         set_opt (sbi->s_mount_opt, XATTR_USER);
 440                         break;
 441                 case Opt_nouser_xattr:
 442                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 443                         break;
 444 #else
 445                 case Opt_user_xattr:
 446                 case Opt_nouser_xattr:
 447                         printk("EXT2 (no)user_xattr options not supported\n");
 448                         break;
 449 #endif
 450 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 451                 case Opt_acl:
 452                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 453                         break;
 454                 case Opt_noacl:
 455                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 456                         break;
 457 #else
 458                 case Opt_acl:
 459                 case Opt_noacl:
 460                         printk("EXT2 (no)acl options not supported\n");
 461                         break;
 462 #endif
 463                 case Opt_xip:
 464 #ifdef CONFIG_EXT2_FS_XIP
 465                         set_opt (sbi->s_mount_opt, XIP);
 466 #else
 467                         printk("EXT2 xip option not supported\n");
 468 #endif
 469                         break;
 470
 471 #if defined(CONFIG_QUOTA)
 472                 case Opt_quota:
 473                 case Opt_usrquota:
 474                         set_opt(sbi->s_mount_opt, USRQUOTA);
 475                         break;
 476
 477                 case Opt_grpquota:
 478                         set_opt(sbi->s_mount_opt, GRPQUOTA);
 479                         break;
 480 #else
 481                 case Opt_quota:
 482                 case Opt_usrquota:
 483                 case Opt_grpquota:
 484                         printk(KERN_ERR
 485                                 "EXT2-fs: quota operations not supported.\n");
 486
 487                         break;
 488 #endif
 489
 490                 case Opt_ignore:
 491                         break;
 492                 default:
 493                         return 0;
 494                 }
 495         }
 496         return 1;
 497 }
 498
 499 static int ext2_setup_super (struct super_block * sb,
 500                               struct ext2_super_block * es,
 501                               int read_only)
 502 {
 503         int res = 0;
 504         struct ext2_sb_info *sbi = EXT2_SB(sb);
 505
 506         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 507                 printk ("EXT2-fs warning: revision level too high, "
 508                         "forcing read-only mode\n");
 509                 res = MS_RDONLY;
 510         }
 511         if (read_only)
 512                 return res;
 513         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 514                 printk ("EXT2-fs warning: mounting unchecked fs, "
 515                         "running e2fsck is recommended\n");
 516         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 517                 printk ("EXT2-fs warning: mounting fs with errors, "
 518                         "running e2fsck is recommended\n");
 519         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 520                  le16_to_cpu(es->s_mnt_count) >=
 521                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 522                 printk ("EXT2-fs warning: maximal mount count reached, "
 523                         "running e2fsck is recommended\n");
 524         else if (le32_to_cpu(es->s_checkinterval) &&
 525                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 526                 printk ("EXT2-fs warning: checktime reached, "
 527                         "running e2fsck is recommended\n");
 528         if (!le16_to_cpu(es->s_max_mnt_count))
 529                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 530         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 531         ext2_write_super(sb);
 532         if (test_opt (sb, DEBUG))
 533                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 534                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 535                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 536                         sbi->s_frag_size,
 537                         sbi->s_groups_count,
 538                         EXT2_BLOCKS_PER_GROUP(sb),
 539                         EXT2_INODES_PER_GROUP(sb),
 540                         sbi->s_mount_opt);
 541         return res;
 542 }
 543
 544 static int ext2_check_descriptors (struct super_block * sb)
 545 {
 546         int i;
 547         int desc_block = 0;
 548         struct ext2_sb_info *sbi = EXT2_SB(sb);
 549         unsigned long first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 550         unsigned long last_block;
 551         struct ext2_group_desc * gdp = NULL;
 552
 553         ext2_debug ("Checking group descriptors");
 554
 555         for (i = 0; i < sbi->s_groups_count; i++)
 556         {
 557                 if (i == sbi->s_groups_count - 1)
 558                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
 559                 else
 560                         last_block = first_block +
 561                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
 562
 563                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 564                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
 565                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
 566                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
 567                 {
 568                         ext2_error (sb, "ext2_check_descriptors",
 569                                     "Block bitmap for group %d"
 570                                     " not in group (block %lu)!",
 571                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 572                         return 0;
 573                 }
 574                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
 575                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
 576                 {
 577                         ext2_error (sb, "ext2_check_descriptors",
 578                                     "Inode bitmap for group %d"
 579                                     " not in group (block %lu)!",
 580                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 581                         return 0;
 582                 }
 583                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
 584                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >
 585                     last_block)
 586                 {
 587                         ext2_error (sb, "ext2_check_descriptors",
 588                                     "Inode table for group %d"
 589                                     " not in group (block %lu)!",
 590                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 591                         return 0;
 592                 }
 593                 first_block += EXT2_BLOCKS_PER_GROUP(sb);
 594                 gdp++;
 595         }
 596         return 1;
 597 }
 598
 599 /*
 600  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 601  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 602  * We need to be 1 filesystem block less than the 2^32 sector limit.
 603  */
 604 static loff_t ext2_max_size(int bits)
 605 {
 606         loff_t res = EXT2_NDIR_BLOCKS;
 607         /* This constant is calculated to be the largest file size for a
 608          * dense, 4k-blocksize file such that the total number of
 609          * sectors in the file, including data and all indirect blocks,
 610          * does not exceed 2^32. */
 611         const loff_t upper_limit = 0x1ff7fffd000LL;
 612
 613         res += 1LL << (bits-2);
 614         res += 1LL << (2*(bits-2));
 615         res += 1LL << (3*(bits-2));
 616         res <<= bits;
 617         if (res > upper_limit)
 618                 res = upper_limit;
 619         return res;
 620 }
 621
 622 static unsigned long descriptor_loc(struct super_block *sb,
 623                                     unsigned long logic_sb_block,
 624                                     int nr)
 625 {
 626         struct ext2_sb_info *sbi = EXT2_SB(sb);
 627         unsigned long bg, first_data_block, first_meta_bg;
 628         int has_super = 0;
 629
 630         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 631         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 632
 633         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 634             nr < first_meta_bg)
 635                 return (logic_sb_block + nr + 1);
 636         bg = sbi->s_desc_per_block * nr;
 637         if (ext2_bg_has_super(sb, bg))
 638                 has_super = 1;
 639         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 640 }
 641
 642 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 643 {
 644         struct buffer_head * bh;
 645         struct ext2_sb_info * sbi;
 646         struct ext2_super_block * es;
 647         struct inode *root;
 648         unsigned long block;
 649         unsigned long sb_block = get_sb_block(&data);
 650         unsigned long logic_sb_block;
 651         unsigned long offset = 0;
 652         unsigned long def_mount_opts;
 653         int blocksize = BLOCK_SIZE;
 654         int db_count;
 655         int i, j;
 656         __le32 features;
 657
 658         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 659         if (!sbi)
 660                 return -ENOMEM;
 661         sb->s_fs_info = sbi;
 662
 663         /*
 664          * See what the current blocksize for the device is, and
 665          * use that as the blocksize.  Otherwise (or if the blocksize
 666          * is smaller than the default) use the default.
 667          * This is important for devices that have a hardware
 668          * sectorsize that is larger than the default.
 669          */
 670         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 671         if (!blocksize) {
 672                 printk ("EXT2-fs: unable to set blocksize\n");
 673                 goto failed_sbi;
 674         }
 675
 676         /*
 677          * If the superblock doesn't start on a hardware sector boundary,
 678          * calculate the offset.
 679          */
 680         if (blocksize != BLOCK_SIZE) {
 681                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 682                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 683         } else {
 684                 logic_sb_block = sb_block;
 685         }
 686
 687         if (!(bh = sb_bread(sb, logic_sb_block))) {
 688                 printk ("EXT2-fs: unable to read superblock\n");
 689                 goto failed_sbi;
 690         }
 691         /*
 692          * Note: s_es must be initialized as soon as possible because
 693          *       some ext2 macro-instructions depend on its value
 694          */
 695         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 696         sbi->s_es = es;
 697         sb->s_magic = le16_to_cpu(es->s_magic);
 698
 699         if (sb->s_magic != EXT2_SUPER_MAGIC)
 700                 goto cantfind_ext2;
 701
 702         /* Set defaults before we parse the mount options */
 703         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 704         if (def_mount_opts & EXT2_DEFM_DEBUG)
 705                 set_opt(sbi->s_mount_opt, DEBUG);
 706         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 707                 set_opt(sbi->s_mount_opt, GRPID);
 708         if (def_mount_opts & EXT2_DEFM_UID16)
 709                 set_opt(sbi->s_mount_opt, NO_UID32);
 710 #ifdef CONFIG_EXT2_FS_XATTR
 711         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 712                 set_opt(sbi->s_mount_opt, XATTR_USER);
 713 #endif
 714 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 715         if (def_mount_opts & EXT2_DEFM_ACL)
 716                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 717 #endif
 718
 719         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 720                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 721         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
 722                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 723         else
 724                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
 725
 726         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 727         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 728
 729         if (!parse_options ((char *) data, sbi))
 730                 goto failed_mount;
 731
 732         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 733                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 734                  MS_POSIXACL : 0);
 735
 736         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
 737                                     EXT2_MOUNT_XIP if not */
 738
 739         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 740             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 741              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 742              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 743                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 744                        "running e2fsck is recommended\n");
 745         /*
 746          * Check feature flags regardless of the revision level, since we
 747          * previously didn't change the revision level when setting the flags,
 748          * so there is a chance incompat flags are set on a rev 0 filesystem.
 749          */
 750         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 751         if (features) {
 752                 printk("EXT2-fs: %s: couldn't mount because of "
 753                        "unsupported optional features (%x).\n",
 754                        sb->s_id, le32_to_cpu(features));
 755                 goto failed_mount;
 756         }
 757         if (!(sb->s_flags & MS_RDONLY) &&
 758             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 759                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 760                        "unsupported optional features (%x).\n",
 761                        sb->s_id, le32_to_cpu(features));
 762                 goto failed_mount;
 763         }
 764
 765         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 766
 767         if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
 768                                   (sb->s_blocksize != blocksize))) {
 769                 if (!silent)
 770                         printk("XIP: Unsupported blocksize\n");
 771                 goto failed_mount;
 772         }
 773
 774         /* If the blocksize doesn't match, re-read the thing.. */
 775         if (sb->s_blocksize != blocksize) {
 776                 brelse(bh);
 777
 778                 if (!sb_set_blocksize(sb, blocksize)) {
 779                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 780                         goto failed_sbi;
 781                 }
 782
 783                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 784                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 785                 bh = sb_bread(sb, logic_sb_block);
 786                 if(!bh) {
 787                         printk("EXT2-fs: Couldn't read superblock on "
 788                                "2nd try.\n");
 789                         goto failed_sbi;
 790                 }
 791                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 792                 sbi->s_es = es;
 793                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 794                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 795                         goto failed_mount;
 796                 }
 797         }
 798
 799         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 800
 801         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 802                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 803                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 804         } else {
 805                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 806                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 807                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 808                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
 809                     (sbi->s_inode_size > blocksize)) {
 810                         printk ("EXT2-fs: unsupported inode size: %d\n",
 811                                 sbi->s_inode_size);
 812                         goto failed_mount;
 813                 }
 814         }
 815
 816         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 817                                    le32_to_cpu(es->s_log_frag_size);
 818         if (sbi->s_frag_size == 0)
 819                 goto cantfind_ext2;
 820         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 821
 822         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 823         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 824         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 825
 826         if (EXT2_INODE_SIZE(sb) == 0)
 827                 goto cantfind_ext2;
 828         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 829         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
 830                 goto cantfind_ext2;
 831         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 832                                         sbi->s_inodes_per_block;
 833         sbi->s_desc_per_block = sb->s_blocksize /
 834                                         sizeof (struct ext2_group_desc);
 835         sbi->s_sbh = bh;
 836         sbi->s_mount_state = le16_to_cpu(es->s_state);
 837         sbi->s_addr_per_block_bits =
 838                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
 839         sbi->s_desc_per_block_bits =
 840                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
 841
 842         if (sb->s_magic != EXT2_SUPER_MAGIC)
 843                 goto cantfind_ext2;
 844
 845         if (sb->s_blocksize != bh->b_size) {
 846                 if (!silent)
 847                         printk ("VFS: Unsupported blocksize on dev "
 848                                 "%s.\n", sb->s_id);
 849                 goto failed_mount;
 850         }
 851
 852         if (sb->s_blocksize != sbi->s_frag_size) {
 853                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 854                         sbi->s_frag_size, sb->s_blocksize);
 855                 goto failed_mount;
 856         }
 857
 858         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 859                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 860                         sbi->s_blocks_per_group);
 861                 goto failed_mount;
 862         }
 863         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 864                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 865                         sbi->s_frags_per_group);
 866                 goto failed_mount;
 867         }
 868         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 869                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 870                         sbi->s_inodes_per_group);
 871                 goto failed_mount;
 872         }
 873
 874         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 875                 goto cantfind_ext2;
 876         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
 877                                 le32_to_cpu(es->s_first_data_block) - 1)
 878                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
 879         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 880                    EXT2_DESC_PER_BLOCK(sb);
 881         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 882         if (sbi->s_group_desc == NULL) {
 883                 printk ("EXT2-fs: not enough memory\n");
 884                 goto failed_mount;
 885         }
 886         bgl_lock_init(&sbi->s_blockgroup_lock);
 887         sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
 888                                GFP_KERNEL);
 889         if (!sbi->s_debts) {
 890                 printk ("EXT2-fs: not enough memory\n");
 891                 goto failed_mount_group_desc;
 892         }
 893         memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
 894         for (i = 0; i < db_count; i++) {
 895                 block = descriptor_loc(sb, logic_sb_block, i);
 896                 sbi->s_group_desc[i] = sb_bread(sb, block);
 897                 if (!sbi->s_group_desc[i]) {
 898                         for (j = 0; j < i; j++)
 899                                 brelse (sbi->s_group_desc[j]);
 900                         printk ("EXT2-fs: unable to read group descriptors\n");
 901                         goto failed_mount_group_desc;
 902                 }
 903         }
 904         if (!ext2_check_descriptors (sb)) {
 905                 printk ("EXT2-fs: group descriptors corrupted!\n");
 906                 goto failed_mount2;
 907         }
 908         sbi->s_gdb_count = db_count;
 909         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 910         spin_lock_init(&sbi->s_next_gen_lock);
 911
 912         percpu_counter_init(&sbi->s_freeblocks_counter,
 913                                 ext2_count_free_blocks(sb));
 914         percpu_counter_init(&sbi->s_freeinodes_counter,
 915                                 ext2_count_free_inodes(sb));
 916         percpu_counter_init(&sbi->s_dirs_counter,
 917                                 ext2_count_dirs(sb));
 918         /*
 919          * set up enough so that it can read an inode
 920          */
 921         sb->s_op = &ext2_sops;
 922         sb->s_export_op = &ext2_export_ops;
 923         sb->s_xattr = ext2_xattr_handlers;
 924         root = iget(sb, EXT2_ROOT_INO);
 925         sb->s_root = d_alloc_root(root);
 926         if (!sb->s_root) {
 927                 iput(root);
 928                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 929                 goto failed_mount3;
 930         }
 931         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 932                 dput(sb->s_root);
 933                 sb->s_root = NULL;
 934                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 935                 goto failed_mount3;
 936         }
 937         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 938                 ext2_warning(sb, __FUNCTION__,
 939                         "mounting ext3 filesystem as ext2");
 940         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 941         return 0;
 942
 943 cantfind_ext2:
 944         if (!silent)
 945                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
 946                        sb->s_id);
 947         goto failed_mount;
 948 failed_mount3:
 949         percpu_counter_destroy(&sbi->s_freeblocks_counter);
 950         percpu_counter_destroy(&sbi->s_freeinodes_counter);
 951         percpu_counter_destroy(&sbi->s_dirs_counter);
 952 failed_mount2:
 953         for (i = 0; i < db_count; i++)
 954                 brelse(sbi->s_group_desc[i]);
 955 failed_mount_group_desc:
 956         kfree(sbi->s_group_desc);
 957         kfree(sbi->s_debts);
 958 failed_mount:
 959         brelse(bh);
 960 failed_sbi:
 961         sb->s_fs_info = NULL;
 962         kfree(sbi);
 963         return -EINVAL;
 964 }
 965
 966 static void ext2_commit_super (struct super_block * sb,
 967                                struct ext2_super_block * es)
 968 {
 969         es->s_wtime = cpu_to_le32(get_seconds());
 970         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 971         sb->s_dirt = 0;
 972 }
 973
 974 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
 975 {
 976         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 977         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 978         es->s_wtime = cpu_to_le32(get_seconds());
 979         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 980         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
 981         sb->s_dirt = 0;
 982 }
 983
 984 /*
 985  * In the second extended file system, it is not necessary to
 986  * write the super block since we use a mapping of the
 987  * disk super block in a buffer.
 988  *
 989  * However, this function is still used to set the fs valid
 990  * flags to 0.  We need to set this flag to 0 since the fs
 991  * may have been checked while mounted and e2fsck may have
 992  * set s_state to EXT2_VALID_FS after some corrections.
 993  */
 994
 995 void ext2_write_super (struct super_block * sb)
 996 {
 997         struct ext2_super_block * es;
 998         lock_kernel();
 999         if (!(sb->s_flags & MS_RDONLY)) {
1000                 es = EXT2_SB(sb)->s_es;
1001
1002                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
1003                         ext2_debug ("setting valid to 0\n");
1004                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
1005                                                   ~EXT2_VALID_FS);
1006                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1007                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1008                         es->s_mtime = cpu_to_le32(get_seconds());
1009                         ext2_sync_super(sb, es);
1010                 } else
1011                         ext2_commit_super (sb, es);
1012         }
1013         sb->s_dirt = 0;
1014         unlock_kernel();
1015 }
1016
1017 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1018 {
1019         struct ext2_sb_info * sbi = EXT2_SB(sb);
1020         struct ext2_super_block * es;
1021         unsigned long old_mount_opt = sbi->s_mount_opt;
1022         struct ext2_mount_options old_opts;
1023         unsigned long old_sb_flags;
1024         int err;
1025
1026         /* Store the old options */
1027         old_sb_flags = sb->s_flags;
1028         old_opts.s_mount_opt = sbi->s_mount_opt;
1029         old_opts.s_resuid = sbi->s_resuid;
1030         old_opts.s_resgid = sbi->s_resgid;
1031
1032         /*
1033          * Allow the "check" option to be passed as a remount option.
1034          */
1035         if (!parse_options (data, sbi)) {
1036                 err = -EINVAL;
1037                 goto restore_opts;
1038         }
1039
1040         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1041                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1042
1043         es = sbi->s_es;
1044         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1045             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1046             invalidate_inodes(sb))
1047                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1048                              "xip remain in cache (no functional problem)");
1049         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1050                 return 0;
1051         if (*flags & MS_RDONLY) {
1052                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1053                     !(sbi->s_mount_state & EXT2_VALID_FS))
1054                         return 0;
1055                 /*
1056                  * OK, we are remounting a valid rw partition rdonly, so set
1057                  * the rdonly flag and then mark the partition as valid again.
1058                  */
1059                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1060                 es->s_mtime = cpu_to_le32(get_seconds());
1061         } else {
1062                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1063                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1064                 if (ret) {
1065                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1066                                "unsupported optional features (%x).\n",
1067                                sb->s_id, le32_to_cpu(ret));
1068                         err = -EROFS;
1069                         goto restore_opts;
1070                 }
1071                 /*
1072                  * Mounting a RDONLY partition read-write, so reread and
1073                  * store the current valid flag.  (It may have been changed
1074                  * by e2fsck since we originally mounted the partition.)
1075                  */
1076                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1077                 if (!ext2_setup_super (sb, es, 0))
1078                         sb->s_flags &= ~MS_RDONLY;
1079         }
1080         ext2_sync_super(sb, es);
1081         return 0;
1082 restore_opts:
1083         sbi->s_mount_opt = old_opts.s_mount_opt;
1084         sbi->s_resuid = old_opts.s_resuid;
1085         sbi->s_resgid = old_opts.s_resgid;
1086         sb->s_flags = old_sb_flags;
1087         return err;
1088 }
1089
1090 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1091 {
1092         struct super_block *sb = dentry->d_sb;
1093         struct ext2_sb_info *sbi = EXT2_SB(sb);
1094         struct ext2_super_block *es = sbi->s_es;
1095         unsigned long overhead;
1096         int i;
1097         u64 fsid;
1098
1099         if (test_opt (sb, MINIX_DF))
1100                 overhead = 0;
1101         else {
1102                 /*
1103                  * Compute the overhead (FS structures)
1104                  */
1105
1106                 /*
1107                  * All of the blocks before first_data_block are
1108                  * overhead
1109                  */
1110                 overhead = le32_to_cpu(es->s_first_data_block);
1111
1112                 /*
1113                  * Add the overhead attributed to the superblock and
1114                  * block group descriptors.  If the sparse superblocks
1115                  * feature is turned on, then not all groups have this.
1116                  */
1117                 for (i = 0; i < sbi->s_groups_count; i++)
1118                         overhead += ext2_bg_has_super(sb, i) +
1119                                 ext2_bg_num_gdb(sb, i);
1120
1121                 /*
1122                  * Every block group has an inode bitmap, a block
1123                  * bitmap, and an inode table.
1124                  */
1125                 overhead += (sbi->s_groups_count *
1126                              (2 + sbi->s_itb_per_group));
1127         }
1128
1129         buf->f_type = EXT2_SUPER_MAGIC;
1130         buf->f_bsize = sb->s_blocksize;
1131         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - overhead;
1132         buf->f_bfree = ext2_count_free_blocks(sb);
1133         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1134         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1135                 buf->f_bavail = 0;
1136         buf->f_files = le32_to_cpu(es->s_inodes_count);
1137         buf->f_ffree = ext2_count_free_inodes(sb);
1138         buf->f_namelen = EXT2_NAME_LEN;
1139         fsid = le64_to_cpup((void *)es->s_uuid) ^
1140                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1141         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1142         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1143         return 0;
1144 }
1145
1146 static int ext2_get_sb(struct file_system_type *fs_type,
1147         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1148 {
1149         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1150 }
1151
1152 #ifdef CONFIG_QUOTA
1153
1154 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1155  * acquiring the locks... As quota files are never truncated and quota code
1156  * itself serializes the operations (and noone else should touch the files)
1157  * we don't have to be afraid of races */
1158 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1159                                size_t len, loff_t off)
1160 {
1161         struct inode *inode = sb_dqopt(sb)->files[type];
1162         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1163         int err = 0;
1164         int offset = off & (sb->s_blocksize - 1);
1165         int tocopy;
1166         size_t toread;
1167         struct buffer_head tmp_bh;
1168         struct buffer_head *bh;
1169         loff_t i_size = i_size_read(inode);
1170
1171         if (off > i_size)
1172                 return 0;
1173         if (off+len > i_size)
1174                 len = i_size-off;
1175         toread = len;
1176         while (toread > 0) {
1177                 tocopy = sb->s_blocksize - offset < toread ?
1178                                 sb->s_blocksize - offset : toread;
1179
1180                 tmp_bh.b_state = 0;
1181                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1182                 if (err)
1183                         return err;
1184                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1185                         memset(data, 0, tocopy);
1186                 else {
1187                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1188                         if (!bh)
1189                                 return -EIO;
1190                         memcpy(data, bh->b_data+offset, tocopy);
1191                         brelse(bh);
1192                 }
1193                 offset = 0;
1194                 toread -= tocopy;
1195                 data += tocopy;
1196                 blk++;
1197         }
1198         return len;
1199 }
1200
1201 /* Write to quotafile */
1202 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1203                                 const char *data, size_t len, loff_t off)
1204 {
1205         struct inode *inode = sb_dqopt(sb)->files[type];
1206         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1207         int err = 0;
1208         int offset = off & (sb->s_blocksize - 1);
1209         int tocopy;
1210         size_t towrite = len;
1211         struct buffer_head tmp_bh;
1212         struct buffer_head *bh;
1213
1214         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1215         while (towrite > 0) {
1216                 tocopy = sb->s_blocksize - offset < towrite ?
1217                                 sb->s_blocksize - offset : towrite;
1218
1219                 tmp_bh.b_state = 0;
1220                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1221                 if (err)
1222                         goto out;
1223                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1224                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1225                 else
1226                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1227                 if (!bh) {
1228                         err = -EIO;
1229                         goto out;
1230                 }
1231                 lock_buffer(bh);
1232                 memcpy(bh->b_data+offset, data, tocopy);
1233                 flush_dcache_page(bh->b_page);
1234                 set_buffer_uptodate(bh);
1235                 mark_buffer_dirty(bh);
1236                 unlock_buffer(bh);
1237                 brelse(bh);
1238                 offset = 0;
1239                 towrite -= tocopy;
1240                 data += tocopy;
1241                 blk++;
1242         }
1243 out:
1244         if (len == towrite)
1245                 return err;
1246         if (inode->i_size < off+len-towrite)
1247                 i_size_write(inode, off+len-towrite);
1248         inode->i_version++;
1249         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1250         mark_inode_dirty(inode);
1251         mutex_unlock(&inode->i_mutex);
1252         return len - towrite;
1253 }
1254
1255 #endif
1256
1257 static struct file_system_type ext2_fs_type = {
1258         .owner          = THIS_MODULE,
1259         .name           = "ext2",
1260         .get_sb         = ext2_get_sb,
1261         .kill_sb        = kill_block_super,
1262         .fs_flags       = FS_REQUIRES_DEV,
1263 };
1264
1265 static int __init init_ext2_fs(void)
1266 {
1267         int err = init_ext2_xattr();
1268         if (err)
1269                 return err;
1270         err = init_inodecache();
1271         if (err)
1272                 goto out1;
1273         err = register_filesystem(&ext2_fs_type);
1274         if (err)
1275                 goto out;
1276         return 0;
1277 out:
1278         destroy_inodecache();
1279 out1:
1280         exit_ext2_xattr();
1281         return err;
1282 }
1283
1284 static void __exit exit_ext2_fs(void)
1285 {
1286         unregister_filesystem(&ext2_fs_type);
1287         destroy_inodecache();
1288         exit_ext2_xattr();
1289 }
1290
1291 module_init(init_ext2_fs)
1292 module_exit(exit_ext2_fs)