git.oblomov.eu Git - 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         rwlock_init(&ei->i_meta_lock);
 164 #ifdef CONFIG_EXT2_FS_XATTR
 165         init_rwsem(&ei->xattr_sem);
 166 #endif
 167         inode_init_once(&ei->vfs_inode);
 168 }
 169
 170 static int init_inodecache(void)
 171 {
 172         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
 173                                              sizeof(struct ext2_inode_info),
 174                                              0, (SLAB_RECLAIM_ACCOUNT|
 175                                                 SLAB_MEM_SPREAD),
 176                                              init_once, NULL);
 177         if (ext2_inode_cachep == NULL)
 178                 return -ENOMEM;
 179         return 0;
 180 }
 181
 182 static void destroy_inodecache(void)
 183 {
 184         kmem_cache_destroy(ext2_inode_cachep);
 185 }
 186
 187 static void ext2_clear_inode(struct inode *inode)
 188 {
 189 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 190         struct ext2_inode_info *ei = EXT2_I(inode);
 191
 192         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
 193                 posix_acl_release(ei->i_acl);
 194                 ei->i_acl = EXT2_ACL_NOT_CACHED;
 195         }
 196         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
 197                 posix_acl_release(ei->i_default_acl);
 198                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 199         }
 200 #endif
 201 }
 202
 203 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 204 {
 205         struct ext2_sb_info *sbi = EXT2_SB(vfs->mnt_sb);
 206
 207         if (sbi->s_mount_opt & EXT2_MOUNT_GRPID)
 208                 seq_puts(seq, ",grpid");
 209
 210 #if defined(CONFIG_QUOTA)
 211         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
 212                 seq_puts(seq, ",usrquota");
 213
 214         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
 215                 seq_puts(seq, ",grpquota");
 216 #endif
 217
 218 #if defined(CONFIG_EXT2_FS_XIP)
 219         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
 220                 seq_puts(seq, ",xip");
 221 #endif
 222
 223         return 0;
 224 }
 225
 226 #ifdef CONFIG_QUOTA
 227 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 228 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 229 #endif
 230
 231 static const struct super_operations ext2_sops = {
 232         .alloc_inode    = ext2_alloc_inode,
 233         .destroy_inode  = ext2_destroy_inode,
 234         .read_inode     = ext2_read_inode,
 235         .write_inode    = ext2_write_inode,
 236         .put_inode      = ext2_put_inode,
 237         .delete_inode   = ext2_delete_inode,
 238         .put_super      = ext2_put_super,
 239         .write_super    = ext2_write_super,
 240         .statfs         = ext2_statfs,
 241         .remount_fs     = ext2_remount,
 242         .clear_inode    = ext2_clear_inode,
 243         .show_options   = ext2_show_options,
 244 #ifdef CONFIG_QUOTA
 245         .quota_read     = ext2_quota_read,
 246         .quota_write    = ext2_quota_write,
 247 #endif
 248 };
 249
 250 static struct dentry *ext2_get_dentry(struct super_block *sb, void *vobjp)
 251 {
 252         __u32 *objp = vobjp;
 253         unsigned long ino = objp[0];
 254         __u32 generation = objp[1];
 255         struct inode *inode;
 256         struct dentry *result;
 257
 258         if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
 259                 return ERR_PTR(-ESTALE);
 260         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
 261                 return ERR_PTR(-ESTALE);
 262
 263         /* iget isn't really right if the inode is currently unallocated!!
 264          * ext2_read_inode currently does appropriate checks, but
 265          * it might be "neater" to call ext2_get_inode first and check
 266          * if the inode is valid.....
 267          */
 268         inode = iget(sb, ino);
 269         if (inode == NULL)
 270                 return ERR_PTR(-ENOMEM);
 271         if (is_bad_inode(inode) ||
 272             (generation && inode->i_generation != generation)) {
 273                 /* we didn't find the right inode.. */
 274                 iput(inode);
 275                 return ERR_PTR(-ESTALE);
 276         }
 277         /* now to find a dentry.
 278          * If possible, get a well-connected one
 279          */
 280         result = d_alloc_anon(inode);
 281         if (!result) {
 282                 iput(inode);
 283                 return ERR_PTR(-ENOMEM);
 284         }
 285         return result;
 286 }
 287
 288 /* Yes, most of these are left as NULL!!
 289  * A NULL value implies the default, which works with ext2-like file
 290  * systems, but can be improved upon.
 291  * Currently only get_parent is required.
 292  */
 293 static struct export_operations ext2_export_ops = {
 294         .get_parent = ext2_get_parent,
 295         .get_dentry = ext2_get_dentry,
 296 };
 297
 298 static unsigned long get_sb_block(void **data)
 299 {
 300         unsigned long   sb_block;
 301         char            *options = (char *) *data;
 302
 303         if (!options || strncmp(options, "sb=", 3) != 0)
 304                 return 1;       /* Default location */
 305         options += 3;
 306         sb_block = simple_strtoul(options, &options, 0);
 307         if (*options && *options != ',') {
 308                 printk("EXT2-fs: Invalid sb specification: %s\n",
 309                        (char *) *data);
 310                 return 1;
 311         }
 312         if (*options == ',')
 313                 options++;
 314         *data = (void *) options;
 315         return sb_block;
 316 }
 317
 318 enum {
 319         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 320         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
 321         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
 322         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
 323         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
 324         Opt_usrquota, Opt_grpquota
 325 };
 326
 327 static match_table_t tokens = {
 328         {Opt_bsd_df, "bsddf"},
 329         {Opt_minix_df, "minixdf"},
 330         {Opt_grpid, "grpid"},
 331         {Opt_grpid, "bsdgroups"},
 332         {Opt_nogrpid, "nogrpid"},
 333         {Opt_nogrpid, "sysvgroups"},
 334         {Opt_resgid, "resgid=%u"},
 335         {Opt_resuid, "resuid=%u"},
 336         {Opt_sb, "sb=%u"},
 337         {Opt_err_cont, "errors=continue"},
 338         {Opt_err_panic, "errors=panic"},
 339         {Opt_err_ro, "errors=remount-ro"},
 340         {Opt_nouid32, "nouid32"},
 341         {Opt_nocheck, "check=none"},
 342         {Opt_nocheck, "nocheck"},
 343         {Opt_debug, "debug"},
 344         {Opt_oldalloc, "oldalloc"},
 345         {Opt_orlov, "orlov"},
 346         {Opt_nobh, "nobh"},
 347         {Opt_user_xattr, "user_xattr"},
 348         {Opt_nouser_xattr, "nouser_xattr"},
 349         {Opt_acl, "acl"},
 350         {Opt_noacl, "noacl"},
 351         {Opt_xip, "xip"},
 352         {Opt_grpquota, "grpquota"},
 353         {Opt_ignore, "noquota"},
 354         {Opt_quota, "quota"},
 355         {Opt_usrquota, "usrquota"},
 356         {Opt_err, NULL}
 357 };
 358
 359 static int parse_options (char * options,
 360                           struct ext2_sb_info *sbi)
 361 {
 362         char * p;
 363         substring_t args[MAX_OPT_ARGS];
 364         int option;
 365
 366         if (!options)
 367                 return 1;
 368
 369         while ((p = strsep (&options, ",")) != NULL) {
 370                 int token;
 371                 if (!*p)
 372                         continue;
 373
 374                 token = match_token(p, tokens, args);
 375                 switch (token) {
 376                 case Opt_bsd_df:
 377                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 378                         break;
 379                 case Opt_minix_df:
 380                         set_opt (sbi->s_mount_opt, MINIX_DF);
 381                         break;
 382                 case Opt_grpid:
 383                         set_opt (sbi->s_mount_opt, GRPID);
 384                         break;
 385                 case Opt_nogrpid:
 386                         clear_opt (sbi->s_mount_opt, GRPID);
 387                         break;
 388                 case Opt_resuid:
 389                         if (match_int(&args[0], &option))
 390                                 return 0;
 391                         sbi->s_resuid = option;
 392                         break;
 393                 case Opt_resgid:
 394                         if (match_int(&args[0], &option))
 395                                 return 0;
 396                         sbi->s_resgid = option;
 397                         break;
 398                 case Opt_sb:
 399                         /* handled by get_sb_block() instead of here */
 400                         /* *sb_block = match_int(&args[0]); */
 401                         break;
 402                 case Opt_err_panic:
 403                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 404                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
 405                         set_opt (sbi->s_mount_opt, ERRORS_PANIC);
 406                         break;
 407                 case Opt_err_ro:
 408                         clear_opt (sbi->s_mount_opt, ERRORS_CONT);
 409                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 410                         set_opt (sbi->s_mount_opt, ERRORS_RO);
 411                         break;
 412                 case Opt_err_cont:
 413                         clear_opt (sbi->s_mount_opt, ERRORS_RO);
 414                         clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
 415                         set_opt (sbi->s_mount_opt, ERRORS_CONT);
 416                         break;
 417                 case Opt_nouid32:
 418                         set_opt (sbi->s_mount_opt, NO_UID32);
 419                         break;
 420                 case Opt_nocheck:
 421                         clear_opt (sbi->s_mount_opt, CHECK);
 422                         break;
 423                 case Opt_debug:
 424                         set_opt (sbi->s_mount_opt, DEBUG);
 425                         break;
 426                 case Opt_oldalloc:
 427                         set_opt (sbi->s_mount_opt, OLDALLOC);
 428                         break;
 429                 case Opt_orlov:
 430                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 431                         break;
 432                 case Opt_nobh:
 433                         set_opt (sbi->s_mount_opt, NOBH);
 434                         break;
 435 #ifdef CONFIG_EXT2_FS_XATTR
 436                 case Opt_user_xattr:
 437                         set_opt (sbi->s_mount_opt, XATTR_USER);
 438                         break;
 439                 case Opt_nouser_xattr:
 440                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 441                         break;
 442 #else
 443                 case Opt_user_xattr:
 444                 case Opt_nouser_xattr:
 445                         printk("EXT2 (no)user_xattr options not supported\n");
 446                         break;
 447 #endif
 448 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 449                 case Opt_acl:
 450                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 451                         break;
 452                 case Opt_noacl:
 453                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 454                         break;
 455 #else
 456                 case Opt_acl:
 457                 case Opt_noacl:
 458                         printk("EXT2 (no)acl options not supported\n");
 459                         break;
 460 #endif
 461                 case Opt_xip:
 462 #ifdef CONFIG_EXT2_FS_XIP
 463                         set_opt (sbi->s_mount_opt, XIP);
 464 #else
 465                         printk("EXT2 xip option not supported\n");
 466 #endif
 467                         break;
 468
 469 #if defined(CONFIG_QUOTA)
 470                 case Opt_quota:
 471                 case Opt_usrquota:
 472                         set_opt(sbi->s_mount_opt, USRQUOTA);
 473                         break;
 474
 475                 case Opt_grpquota:
 476                         set_opt(sbi->s_mount_opt, GRPQUOTA);
 477                         break;
 478 #else
 479                 case Opt_quota:
 480                 case Opt_usrquota:
 481                 case Opt_grpquota:
 482                         printk(KERN_ERR
 483                                 "EXT2-fs: quota operations not supported.\n");
 484
 485                         break;
 486 #endif
 487
 488                 case Opt_ignore:
 489                         break;
 490                 default:
 491                         return 0;
 492                 }
 493         }
 494         return 1;
 495 }
 496
 497 static int ext2_setup_super (struct super_block * sb,
 498                               struct ext2_super_block * es,
 499                               int read_only)
 500 {
 501         int res = 0;
 502         struct ext2_sb_info *sbi = EXT2_SB(sb);
 503
 504         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 505                 printk ("EXT2-fs warning: revision level too high, "
 506                         "forcing read-only mode\n");
 507                 res = MS_RDONLY;
 508         }
 509         if (read_only)
 510                 return res;
 511         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 512                 printk ("EXT2-fs warning: mounting unchecked fs, "
 513                         "running e2fsck is recommended\n");
 514         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 515                 printk ("EXT2-fs warning: mounting fs with errors, "
 516                         "running e2fsck is recommended\n");
 517         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 518                  le16_to_cpu(es->s_mnt_count) >=
 519                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 520                 printk ("EXT2-fs warning: maximal mount count reached, "
 521                         "running e2fsck is recommended\n");
 522         else if (le32_to_cpu(es->s_checkinterval) &&
 523                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 524                 printk ("EXT2-fs warning: checktime reached, "
 525                         "running e2fsck is recommended\n");
 526         if (!le16_to_cpu(es->s_max_mnt_count))
 527                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 528         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 529         ext2_write_super(sb);
 530         if (test_opt (sb, DEBUG))
 531                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 532                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 533                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 534                         sbi->s_frag_size,
 535                         sbi->s_groups_count,
 536                         EXT2_BLOCKS_PER_GROUP(sb),
 537                         EXT2_INODES_PER_GROUP(sb),
 538                         sbi->s_mount_opt);
 539         return res;
 540 }
 541
 542 static int ext2_check_descriptors (struct super_block * sb)
 543 {
 544         int i;
 545         int desc_block = 0;
 546         struct ext2_sb_info *sbi = EXT2_SB(sb);
 547         unsigned long first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 548         unsigned long last_block;
 549         struct ext2_group_desc * gdp = NULL;
 550
 551         ext2_debug ("Checking group descriptors");
 552
 553         for (i = 0; i < sbi->s_groups_count; i++)
 554         {
 555                 if (i == sbi->s_groups_count - 1)
 556                         last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
 557                 else
 558                         last_block = first_block +
 559                                 (EXT2_BLOCKS_PER_GROUP(sb) - 1);
 560
 561                 if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
 562                         gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
 563                 if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
 564                     le32_to_cpu(gdp->bg_block_bitmap) > last_block)
 565                 {
 566                         ext2_error (sb, "ext2_check_descriptors",
 567                                     "Block bitmap for group %d"
 568                                     " not in group (block %lu)!",
 569                                     i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
 570                         return 0;
 571                 }
 572                 if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
 573                     le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
 574                 {
 575                         ext2_error (sb, "ext2_check_descriptors",
 576                                     "Inode bitmap for group %d"
 577                                     " not in group (block %lu)!",
 578                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
 579                         return 0;
 580                 }
 581                 if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
 582                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >
 583                     last_block)
 584                 {
 585                         ext2_error (sb, "ext2_check_descriptors",
 586                                     "Inode table for group %d"
 587                                     " not in group (block %lu)!",
 588                                     i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
 589                         return 0;
 590                 }
 591                 first_block += EXT2_BLOCKS_PER_GROUP(sb);
 592                 gdp++;
 593         }
 594         return 1;
 595 }
 596
 597 /*
 598  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 599  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 600  * We need to be 1 filesystem block less than the 2^32 sector limit.
 601  */
 602 static loff_t ext2_max_size(int bits)
 603 {
 604         loff_t res = EXT2_NDIR_BLOCKS;
 605         /* This constant is calculated to be the largest file size for a
 606          * dense, 4k-blocksize file such that the total number of
 607          * sectors in the file, including data and all indirect blocks,
 608          * does not exceed 2^32. */
 609         const loff_t upper_limit = 0x1ff7fffd000LL;
 610
 611         res += 1LL << (bits-2);
 612         res += 1LL << (2*(bits-2));
 613         res += 1LL << (3*(bits-2));
 614         res <<= bits;
 615         if (res > upper_limit)
 616                 res = upper_limit;
 617         return res;
 618 }
 619
 620 static unsigned long descriptor_loc(struct super_block *sb,
 621                                     unsigned long logic_sb_block,
 622                                     int nr)
 623 {
 624         struct ext2_sb_info *sbi = EXT2_SB(sb);
 625         unsigned long bg, first_data_block, first_meta_bg;
 626         int has_super = 0;
 627
 628         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 629         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 630
 631         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 632             nr < first_meta_bg)
 633                 return (logic_sb_block + nr + 1);
 634         bg = sbi->s_desc_per_block * nr;
 635         if (ext2_bg_has_super(sb, bg))
 636                 has_super = 1;
 637         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 638 }
 639
 640 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 641 {
 642         struct buffer_head * bh;
 643         struct ext2_sb_info * sbi;
 644         struct ext2_super_block * es;
 645         struct inode *root;
 646         unsigned long block;
 647         unsigned long sb_block = get_sb_block(&data);
 648         unsigned long logic_sb_block;
 649         unsigned long offset = 0;
 650         unsigned long def_mount_opts;
 651         int blocksize = BLOCK_SIZE;
 652         int db_count;
 653         int i, j;
 654         __le32 features;
 655
 656         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 657         if (!sbi)
 658                 return -ENOMEM;
 659         sb->s_fs_info = sbi;
 660
 661         /*
 662          * See what the current blocksize for the device is, and
 663          * use that as the blocksize.  Otherwise (or if the blocksize
 664          * is smaller than the default) use the default.
 665          * This is important for devices that have a hardware
 666          * sectorsize that is larger than the default.
 667          */
 668         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 669         if (!blocksize) {
 670                 printk ("EXT2-fs: unable to set blocksize\n");
 671                 goto failed_sbi;
 672         }
 673
 674         /*
 675          * If the superblock doesn't start on a hardware sector boundary,
 676          * calculate the offset.
 677          */
 678         if (blocksize != BLOCK_SIZE) {
 679                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 680                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 681         } else {
 682                 logic_sb_block = sb_block;
 683         }
 684
 685         if (!(bh = sb_bread(sb, logic_sb_block))) {
 686                 printk ("EXT2-fs: unable to read superblock\n");
 687                 goto failed_sbi;
 688         }
 689         /*
 690          * Note: s_es must be initialized as soon as possible because
 691          *       some ext2 macro-instructions depend on its value
 692          */
 693         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 694         sbi->s_es = es;
 695         sb->s_magic = le16_to_cpu(es->s_magic);
 696
 697         if (sb->s_magic != EXT2_SUPER_MAGIC)
 698                 goto cantfind_ext2;
 699
 700         /* Set defaults before we parse the mount options */
 701         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 702         if (def_mount_opts & EXT2_DEFM_DEBUG)
 703                 set_opt(sbi->s_mount_opt, DEBUG);
 704         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 705                 set_opt(sbi->s_mount_opt, GRPID);
 706         if (def_mount_opts & EXT2_DEFM_UID16)
 707                 set_opt(sbi->s_mount_opt, NO_UID32);
 708 #ifdef CONFIG_EXT2_FS_XATTR
 709         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 710                 set_opt(sbi->s_mount_opt, XATTR_USER);
 711 #endif
 712 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 713         if (def_mount_opts & EXT2_DEFM_ACL)
 714                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 715 #endif
 716
 717         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 718                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 719         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
 720                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 721         else
 722                 set_opt(sbi->s_mount_opt, ERRORS_CONT);
 723
 724         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 725         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 726
 727         if (!parse_options ((char *) data, sbi))
 728                 goto failed_mount;
 729
 730         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 731                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 732                  MS_POSIXACL : 0);
 733
 734         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
 735                                     EXT2_MOUNT_XIP if not */
 736
 737         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 738             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 739              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 740              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 741                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 742                        "running e2fsck is recommended\n");
 743         /*
 744          * Check feature flags regardless of the revision level, since we
 745          * previously didn't change the revision level when setting the flags,
 746          * so there is a chance incompat flags are set on a rev 0 filesystem.
 747          */
 748         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 749         if (features) {
 750                 printk("EXT2-fs: %s: couldn't mount because of "
 751                        "unsupported optional features (%x).\n",
 752                        sb->s_id, le32_to_cpu(features));
 753                 goto failed_mount;
 754         }
 755         if (!(sb->s_flags & MS_RDONLY) &&
 756             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 757                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 758                        "unsupported optional features (%x).\n",
 759                        sb->s_id, le32_to_cpu(features));
 760                 goto failed_mount;
 761         }
 762
 763         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 764
 765         if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
 766                                   (sb->s_blocksize != blocksize))) {
 767                 if (!silent)
 768                         printk("XIP: Unsupported blocksize\n");
 769                 goto failed_mount;
 770         }
 771
 772         /* If the blocksize doesn't match, re-read the thing.. */
 773         if (sb->s_blocksize != blocksize) {
 774                 brelse(bh);
 775
 776                 if (!sb_set_blocksize(sb, blocksize)) {
 777                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 778                         goto failed_sbi;
 779                 }
 780
 781                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 782                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 783                 bh = sb_bread(sb, logic_sb_block);
 784                 if(!bh) {
 785                         printk("EXT2-fs: Couldn't read superblock on "
 786                                "2nd try.\n");
 787                         goto failed_sbi;
 788                 }
 789                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 790                 sbi->s_es = es;
 791                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 792                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 793                         goto failed_mount;
 794                 }
 795         }
 796
 797         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 798
 799         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 800                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 801                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 802         } else {
 803                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 804                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 805                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 806                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
 807                     (sbi->s_inode_size > blocksize)) {
 808                         printk ("EXT2-fs: unsupported inode size: %d\n",
 809                                 sbi->s_inode_size);
 810                         goto failed_mount;
 811                 }
 812         }
 813
 814         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 815                                    le32_to_cpu(es->s_log_frag_size);
 816         if (sbi->s_frag_size == 0)
 817                 goto cantfind_ext2;
 818         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 819
 820         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 821         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 822         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 823
 824         if (EXT2_INODE_SIZE(sb) == 0)
 825                 goto cantfind_ext2;
 826         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 827         if (sbi->s_inodes_per_block == 0 || sbi->s_inodes_per_group == 0)
 828                 goto cantfind_ext2;
 829         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 830                                         sbi->s_inodes_per_block;
 831         sbi->s_desc_per_block = sb->s_blocksize /
 832                                         sizeof (struct ext2_group_desc);
 833         sbi->s_sbh = bh;
 834         sbi->s_mount_state = le16_to_cpu(es->s_state);
 835         sbi->s_addr_per_block_bits =
 836                 ilog2 (EXT2_ADDR_PER_BLOCK(sb));
 837         sbi->s_desc_per_block_bits =
 838                 ilog2 (EXT2_DESC_PER_BLOCK(sb));
 839
 840         if (sb->s_magic != EXT2_SUPER_MAGIC)
 841                 goto cantfind_ext2;
 842
 843         if (sb->s_blocksize != bh->b_size) {
 844                 if (!silent)
 845                         printk ("VFS: Unsupported blocksize on dev "
 846                                 "%s.\n", sb->s_id);
 847                 goto failed_mount;
 848         }
 849
 850         if (sb->s_blocksize != sbi->s_frag_size) {
 851                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 852                         sbi->s_frag_size, sb->s_blocksize);
 853                 goto failed_mount;
 854         }
 855
 856         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 857                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 858                         sbi->s_blocks_per_group);
 859                 goto failed_mount;
 860         }
 861         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 862                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 863                         sbi->s_frags_per_group);
 864                 goto failed_mount;
 865         }
 866         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 867                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 868                         sbi->s_inodes_per_group);
 869                 goto failed_mount;
 870         }
 871
 872         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 873                 goto cantfind_ext2;
 874         sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
 875                                 le32_to_cpu(es->s_first_data_block) - 1)
 876                                         / EXT2_BLOCKS_PER_GROUP(sb)) + 1;
 877         db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 878                    EXT2_DESC_PER_BLOCK(sb);
 879         sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
 880         if (sbi->s_group_desc == NULL) {
 881                 printk ("EXT2-fs: not enough memory\n");
 882                 goto failed_mount;
 883         }
 884         bgl_lock_init(&sbi->s_blockgroup_lock);
 885         sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
 886                                GFP_KERNEL);
 887         if (!sbi->s_debts) {
 888                 printk ("EXT2-fs: not enough memory\n");
 889                 goto failed_mount_group_desc;
 890         }
 891         memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
 892         for (i = 0; i < db_count; i++) {
 893                 block = descriptor_loc(sb, logic_sb_block, i);
 894                 sbi->s_group_desc[i] = sb_bread(sb, block);
 895                 if (!sbi->s_group_desc[i]) {
 896                         for (j = 0; j < i; j++)
 897                                 brelse (sbi->s_group_desc[j]);
 898                         printk ("EXT2-fs: unable to read group descriptors\n");
 899                         goto failed_mount_group_desc;
 900                 }
 901         }
 902         if (!ext2_check_descriptors (sb)) {
 903                 printk ("EXT2-fs: group descriptors corrupted!\n");
 904                 goto failed_mount2;
 905         }
 906         sbi->s_gdb_count = db_count;
 907         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 908         spin_lock_init(&sbi->s_next_gen_lock);
 909
 910         percpu_counter_init(&sbi->s_freeblocks_counter,
 911                                 ext2_count_free_blocks(sb));
 912         percpu_counter_init(&sbi->s_freeinodes_counter,
 913                                 ext2_count_free_inodes(sb));
 914         percpu_counter_init(&sbi->s_dirs_counter,
 915                                 ext2_count_dirs(sb));
 916         /*
 917          * set up enough so that it can read an inode
 918          */
 919         sb->s_op = &ext2_sops;
 920         sb->s_export_op = &ext2_export_ops;
 921         sb->s_xattr = ext2_xattr_handlers;
 922         root = iget(sb, EXT2_ROOT_INO);
 923         sb->s_root = d_alloc_root(root);
 924         if (!sb->s_root) {
 925                 iput(root);
 926                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 927                 goto failed_mount3;
 928         }
 929         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 930                 dput(sb->s_root);
 931                 sb->s_root = NULL;
 932                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 933                 goto failed_mount3;
 934         }
 935         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 936                 ext2_warning(sb, __FUNCTION__,
 937                         "mounting ext3 filesystem as ext2");
 938         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 939         return 0;
 940
 941 cantfind_ext2:
 942         if (!silent)
 943                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
 944                        sb->s_id);
 945         goto failed_mount;
 946 failed_mount3:
 947         percpu_counter_destroy(&sbi->s_freeblocks_counter);
 948         percpu_counter_destroy(&sbi->s_freeinodes_counter);
 949         percpu_counter_destroy(&sbi->s_dirs_counter);
 950 failed_mount2:
 951         for (i = 0; i < db_count; i++)
 952                 brelse(sbi->s_group_desc[i]);
 953 failed_mount_group_desc:
 954         kfree(sbi->s_group_desc);
 955         kfree(sbi->s_debts);
 956 failed_mount:
 957         brelse(bh);
 958 failed_sbi:
 959         sb->s_fs_info = NULL;
 960         kfree(sbi);
 961         return -EINVAL;
 962 }
 963
 964 static void ext2_commit_super (struct super_block * sb,
 965                                struct ext2_super_block * es)
 966 {
 967         es->s_wtime = cpu_to_le32(get_seconds());
 968         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 969         sb->s_dirt = 0;
 970 }
 971
 972 static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
 973 {
 974         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
 975         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
 976         es->s_wtime = cpu_to_le32(get_seconds());
 977         mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
 978         sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
 979         sb->s_dirt = 0;
 980 }
 981
 982 /*
 983  * In the second extended file system, it is not necessary to
 984  * write the super block since we use a mapping of the
 985  * disk super block in a buffer.
 986  *
 987  * However, this function is still used to set the fs valid
 988  * flags to 0.  We need to set this flag to 0 since the fs
 989  * may have been checked while mounted and e2fsck may have
 990  * set s_state to EXT2_VALID_FS after some corrections.
 991  */
 992
 993 void ext2_write_super (struct super_block * sb)
 994 {
 995         struct ext2_super_block * es;
 996         lock_kernel();
 997         if (!(sb->s_flags & MS_RDONLY)) {
 998                 es = EXT2_SB(sb)->s_es;
 999
1000                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
1001                         ext2_debug ("setting valid to 0\n");
1002                         es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
1003                                                   ~EXT2_VALID_FS);
1004                         es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
1005                         es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
1006                         es->s_mtime = cpu_to_le32(get_seconds());
1007                         ext2_sync_super(sb, es);
1008                 } else
1009                         ext2_commit_super (sb, es);
1010         }
1011         sb->s_dirt = 0;
1012         unlock_kernel();
1013 }
1014
1015 static int ext2_remount (struct super_block * sb, int * flags, char * data)
1016 {
1017         struct ext2_sb_info * sbi = EXT2_SB(sb);
1018         struct ext2_super_block * es;
1019         unsigned long old_mount_opt = sbi->s_mount_opt;
1020         struct ext2_mount_options old_opts;
1021         unsigned long old_sb_flags;
1022         int err;
1023
1024         /* Store the old options */
1025         old_sb_flags = sb->s_flags;
1026         old_opts.s_mount_opt = sbi->s_mount_opt;
1027         old_opts.s_resuid = sbi->s_resuid;
1028         old_opts.s_resgid = sbi->s_resgid;
1029
1030         /*
1031          * Allow the "check" option to be passed as a remount option.
1032          */
1033         if (!parse_options (data, sbi)) {
1034                 err = -EINVAL;
1035                 goto restore_opts;
1036         }
1037
1038         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1039                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1040
1041         es = sbi->s_es;
1042         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1043             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1044             invalidate_inodes(sb))
1045                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1046                              "xip remain in cache (no functional problem)");
1047         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1048                 return 0;
1049         if (*flags & MS_RDONLY) {
1050                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1051                     !(sbi->s_mount_state & EXT2_VALID_FS))
1052                         return 0;
1053                 /*
1054                  * OK, we are remounting a valid rw partition rdonly, so set
1055                  * the rdonly flag and then mark the partition as valid again.
1056                  */
1057                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1058                 es->s_mtime = cpu_to_le32(get_seconds());
1059         } else {
1060                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1061                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1062                 if (ret) {
1063                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1064                                "unsupported optional features (%x).\n",
1065                                sb->s_id, le32_to_cpu(ret));
1066                         err = -EROFS;
1067                         goto restore_opts;
1068                 }
1069                 /*
1070                  * Mounting a RDONLY partition read-write, so reread and
1071                  * store the current valid flag.  (It may have been changed
1072                  * by e2fsck since we originally mounted the partition.)
1073                  */
1074                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1075                 if (!ext2_setup_super (sb, es, 0))
1076                         sb->s_flags &= ~MS_RDONLY;
1077         }
1078         ext2_sync_super(sb, es);
1079         return 0;
1080 restore_opts:
1081         sbi->s_mount_opt = old_opts.s_mount_opt;
1082         sbi->s_resuid = old_opts.s_resuid;
1083         sbi->s_resgid = old_opts.s_resgid;
1084         sb->s_flags = old_sb_flags;
1085         return err;
1086 }
1087
1088 static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
1089 {
1090         struct super_block *sb = dentry->d_sb;
1091         struct ext2_sb_info *sbi = EXT2_SB(sb);
1092         struct ext2_super_block *es = sbi->s_es;
1093         unsigned long overhead;
1094         int i;
1095         u64 fsid;
1096
1097         if (test_opt (sb, MINIX_DF))
1098                 overhead = 0;
1099         else {
1100                 /*
1101                  * Compute the overhead (FS structures)
1102                  */
1103
1104                 /*
1105                  * All of the blocks before first_data_block are
1106                  * overhead
1107                  */
1108                 overhead = le32_to_cpu(es->s_first_data_block);
1109
1110                 /*
1111                  * Add the overhead attributed to the superblock and
1112                  * block group descriptors.  If the sparse superblocks
1113                  * feature is turned on, then not all groups have this.
1114                  */
1115                 for (i = 0; i < sbi->s_groups_count; i++)
1116                         overhead += ext2_bg_has_super(sb, i) +
1117                                 ext2_bg_num_gdb(sb, i);
1118
1119                 /*
1120                  * Every block group has an inode bitmap, a block
1121                  * bitmap, and an inode table.
1122                  */
1123                 overhead += (sbi->s_groups_count *
1124                              (2 + sbi->s_itb_per_group));
1125         }
1126
1127         buf->f_type = EXT2_SUPER_MAGIC;
1128         buf->f_bsize = sb->s_blocksize;
1129         buf->f_blocks = le32_to_cpu(es->s_blocks_count) - overhead;
1130         buf->f_bfree = ext2_count_free_blocks(sb);
1131         buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
1132         if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
1133                 buf->f_bavail = 0;
1134         buf->f_files = le32_to_cpu(es->s_inodes_count);
1135         buf->f_ffree = ext2_count_free_inodes(sb);
1136         buf->f_namelen = EXT2_NAME_LEN;
1137         fsid = le64_to_cpup((void *)es->s_uuid) ^
1138                le64_to_cpup((void *)es->s_uuid + sizeof(u64));
1139         buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
1140         buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
1141         return 0;
1142 }
1143
1144 static int ext2_get_sb(struct file_system_type *fs_type,
1145         int flags, const char *dev_name, void *data, struct vfsmount *mnt)
1146 {
1147         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super, mnt);
1148 }
1149
1150 #ifdef CONFIG_QUOTA
1151
1152 /* Read data from quotafile - avoid pagecache and such because we cannot afford
1153  * acquiring the locks... As quota files are never truncated and quota code
1154  * itself serializes the operations (and noone else should touch the files)
1155  * we don't have to be afraid of races */
1156 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
1157                                size_t len, loff_t off)
1158 {
1159         struct inode *inode = sb_dqopt(sb)->files[type];
1160         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1161         int err = 0;
1162         int offset = off & (sb->s_blocksize - 1);
1163         int tocopy;
1164         size_t toread;
1165         struct buffer_head tmp_bh;
1166         struct buffer_head *bh;
1167         loff_t i_size = i_size_read(inode);
1168
1169         if (off > i_size)
1170                 return 0;
1171         if (off+len > i_size)
1172                 len = i_size-off;
1173         toread = len;
1174         while (toread > 0) {
1175                 tocopy = sb->s_blocksize - offset < toread ?
1176                                 sb->s_blocksize - offset : toread;
1177
1178                 tmp_bh.b_state = 0;
1179                 err = ext2_get_block(inode, blk, &tmp_bh, 0);
1180                 if (err)
1181                         return err;
1182                 if (!buffer_mapped(&tmp_bh))    /* A hole? */
1183                         memset(data, 0, tocopy);
1184                 else {
1185                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1186                         if (!bh)
1187                                 return -EIO;
1188                         memcpy(data, bh->b_data+offset, tocopy);
1189                         brelse(bh);
1190                 }
1191                 offset = 0;
1192                 toread -= tocopy;
1193                 data += tocopy;
1194                 blk++;
1195         }
1196         return len;
1197 }
1198
1199 /* Write to quotafile */
1200 static ssize_t ext2_quota_write(struct super_block *sb, int type,
1201                                 const char *data, size_t len, loff_t off)
1202 {
1203         struct inode *inode = sb_dqopt(sb)->files[type];
1204         sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
1205         int err = 0;
1206         int offset = off & (sb->s_blocksize - 1);
1207         int tocopy;
1208         size_t towrite = len;
1209         struct buffer_head tmp_bh;
1210         struct buffer_head *bh;
1211
1212         mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
1213         while (towrite > 0) {
1214                 tocopy = sb->s_blocksize - offset < towrite ?
1215                                 sb->s_blocksize - offset : towrite;
1216
1217                 tmp_bh.b_state = 0;
1218                 err = ext2_get_block(inode, blk, &tmp_bh, 1);
1219                 if (err)
1220                         goto out;
1221                 if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
1222                         bh = sb_bread(sb, tmp_bh.b_blocknr);
1223                 else
1224                         bh = sb_getblk(sb, tmp_bh.b_blocknr);
1225                 if (!bh) {
1226                         err = -EIO;
1227                         goto out;
1228                 }
1229                 lock_buffer(bh);
1230                 memcpy(bh->b_data+offset, data, tocopy);
1231                 flush_dcache_page(bh->b_page);
1232                 set_buffer_uptodate(bh);
1233                 mark_buffer_dirty(bh);
1234                 unlock_buffer(bh);
1235                 brelse(bh);
1236                 offset = 0;
1237                 towrite -= tocopy;
1238                 data += tocopy;
1239                 blk++;
1240         }
1241 out:
1242         if (len == towrite)
1243                 return err;
1244         if (inode->i_size < off+len-towrite)
1245                 i_size_write(inode, off+len-towrite);
1246         inode->i_version++;
1247         inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1248         mark_inode_dirty(inode);
1249         mutex_unlock(&inode->i_mutex);
1250         return len - towrite;
1251 }
1252
1253 #endif
1254
1255 static struct file_system_type ext2_fs_type = {
1256         .owner          = THIS_MODULE,
1257         .name           = "ext2",
1258         .get_sb         = ext2_get_sb,
1259         .kill_sb        = kill_block_super,
1260         .fs_flags       = FS_REQUIRES_DEV,
1261 };
1262
1263 static int __init init_ext2_fs(void)
1264 {
1265         int err = init_ext2_xattr();
1266         if (err)
1267                 return err;
1268         err = init_inodecache();
1269         if (err)
1270                 goto out1;
1271         err = register_filesystem(&ext2_fs_type);
1272         if (err)
1273                 goto out;
1274         return 0;
1275 out:
1276         destroy_inodecache();
1277 out1:
1278         exit_ext2_xattr();
1279         return err;
1280 }
1281
1282 static void __exit exit_ext2_fs(void)
1283 {
1284         unregister_filesystem(&ext2_fs_type);
1285         destroy_inodecache();
1286         exit_ext2_xattr();
1287 }
1288
1289 module_init(init_ext2_fs)
1290 module_exit(exit_ext2_fs)