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/config.h>
  20 #include <linux/module.h>
  21 #include <linux/string.h>
  22 #include <linux/fs.h>
  23 #include <linux/slab.h>
  24 #include <linux/init.h>
  25 #include <linux/blkdev.h>
  26 #include <linux/parser.h>
  27 #include <linux/random.h>
  28 #include <linux/buffer_head.h>
  29 #include <linux/smp_lock.h>
  30 #include <linux/vfs.h>
  31 #include <linux/seq_file.h>
  32 #include <linux/mount.h>
  33 #include <asm/uaccess.h>
  34 #include "ext2.h"
  35 #include "xattr.h"
  36 #include "acl.h"
  37 #include "xip.h"
  38
  39 static void ext2_sync_super(struct super_block *sb,
  40                             struct ext2_super_block *es);
  41 static int ext2_remount (struct super_block * sb, int * flags, char * data);
  42 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf);
  43
  44 void ext2_error (struct super_block * sb, const char * function,
  45                  const char * fmt, ...)
  46 {
  47         va_list args;
  48         struct ext2_sb_info *sbi = EXT2_SB(sb);
  49         struct ext2_super_block *es = sbi->s_es;
  50
  51         if (!(sb->s_flags & MS_RDONLY)) {
  52                 sbi->s_mount_state |= EXT2_ERROR_FS;
  53                 es->s_state =
  54                         cpu_to_le16(le16_to_cpu(es->s_state) | EXT2_ERROR_FS);
  55                 ext2_sync_super(sb, es);
  56         }
  57
  58         va_start(args, fmt);
  59         printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
  60         vprintk(fmt, args);
  61         printk("\n");
  62         va_end(args);
  63
  64         if (test_opt(sb, ERRORS_PANIC))
  65                 panic("EXT2-fs panic from previous error\n");
  66         if (test_opt(sb, ERRORS_RO)) {
  67                 printk("Remounting filesystem read-only\n");
  68                 sb->s_flags |= MS_RDONLY;
  69         }
  70 }
  71
  72 void ext2_warning (struct super_block * sb, const char * function,
  73                    const char * fmt, ...)
  74 {
  75         va_list args;
  76
  77         va_start(args, fmt);
  78         printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
  79                sb->s_id, function);
  80         vprintk(fmt, args);
  81         printk("\n");
  82         va_end(args);
  83 }
  84
  85 void ext2_update_dynamic_rev(struct super_block *sb)
  86 {
  87         struct ext2_super_block *es = EXT2_SB(sb)->s_es;
  88
  89         if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
  90                 return;
  91
  92         ext2_warning(sb, __FUNCTION__,
  93                      "updating to rev %d because of new feature flag, "
  94                      "running e2fsck is recommended",
  95                      EXT2_DYNAMIC_REV);
  96
  97         es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
  98         es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
  99         es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
 100         /* leave es->s_feature_*compat flags alone */
 101         /* es->s_uuid will be set by e2fsck if empty */
 102
 103         /*
 104          * The rest of the superblock fields should be zero, and if not it
 105          * means they are likely already in use, so leave them alone.  We
 106          * can leave it up to e2fsck to clean up any inconsistencies there.
 107          */
 108 }
 109
 110 static void ext2_put_super (struct super_block * sb)
 111 {
 112         int db_count;
 113         int i;
 114         struct ext2_sb_info *sbi = EXT2_SB(sb);
 115
 116         ext2_xattr_put_super(sb);
 117         if (!(sb->s_flags & MS_RDONLY)) {
 118                 struct ext2_super_block *es = sbi->s_es;
 119
 120                 es->s_state = cpu_to_le16(sbi->s_mount_state);
 121                 ext2_sync_super(sb, es);
 122         }
 123         db_count = sbi->s_gdb_count;
 124         for (i = 0; i < db_count; i++)
 125                 if (sbi->s_group_desc[i])
 126                         brelse (sbi->s_group_desc[i]);
 127         kfree(sbi->s_group_desc);
 128         kfree(sbi->s_debts);
 129         percpu_counter_destroy(&sbi->s_freeblocks_counter);
 130         percpu_counter_destroy(&sbi->s_freeinodes_counter);
 131         percpu_counter_destroy(&sbi->s_dirs_counter);
 132         brelse (sbi->s_sbh);
 133         sb->s_fs_info = NULL;
 134         kfree(sbi);
 135
 136         return;
 137 }
 138
 139 static kmem_cache_t * ext2_inode_cachep;
 140
 141 static struct inode *ext2_alloc_inode(struct super_block *sb)
 142 {
 143         struct ext2_inode_info *ei;
 144         ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, SLAB_KERNEL);
 145         if (!ei)
 146                 return NULL;
 147 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 148         ei->i_acl = EXT2_ACL_NOT_CACHED;
 149         ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 150 #endif
 151         ei->vfs_inode.i_version = 1;
 152         return &ei->vfs_inode;
 153 }
 154
 155 static void ext2_destroy_inode(struct inode *inode)
 156 {
 157         kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
 158 }
 159
 160 static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
 161 {
 162         struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
 163
 164         if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
 165             SLAB_CTOR_CONSTRUCTOR) {
 166                 rwlock_init(&ei->i_meta_lock);
 167 #ifdef CONFIG_EXT2_FS_XATTR
 168                 init_rwsem(&ei->xattr_sem);
 169 #endif
 170                 inode_init_once(&ei->vfs_inode);
 171         }
 172 }
 173
 174 static int init_inodecache(void)
 175 {
 176         ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
 177                                              sizeof(struct ext2_inode_info),
 178                                              0, (SLAB_RECLAIM_ACCOUNT|
 179                                                 SLAB_MEM_SPREAD),
 180                                              init_once, NULL);
 181         if (ext2_inode_cachep == NULL)
 182                 return -ENOMEM;
 183         return 0;
 184 }
 185
 186 static void destroy_inodecache(void)
 187 {
 188         if (kmem_cache_destroy(ext2_inode_cachep))
 189                 printk(KERN_INFO "ext2_inode_cache: not all structures were freed\n");
 190 }
 191
 192 static void ext2_clear_inode(struct inode *inode)
 193 {
 194 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 195         struct ext2_inode_info *ei = EXT2_I(inode);
 196
 197         if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
 198                 posix_acl_release(ei->i_acl);
 199                 ei->i_acl = EXT2_ACL_NOT_CACHED;
 200         }
 201         if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
 202                 posix_acl_release(ei->i_default_acl);
 203                 ei->i_default_acl = EXT2_ACL_NOT_CACHED;
 204         }
 205 #endif
 206 }
 207
 208 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 209 {
 210         struct ext2_sb_info *sbi = EXT2_SB(vfs->mnt_sb);
 211
 212         if (sbi->s_mount_opt & EXT2_MOUNT_GRPID)
 213                 seq_puts(seq, ",grpid");
 214
 215 #if defined(CONFIG_QUOTA)
 216         if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
 217                 seq_puts(seq, ",usrquota");
 218
 219         if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
 220                 seq_puts(seq, ",grpquota");
 221 #endif
 222
 223 #if defined(CONFIG_EXT2_FS_XIP)
 224         if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
 225                 seq_puts(seq, ",xip");
 226 #endif
 227
 228         return 0;
 229 }
 230
 231 #ifdef CONFIG_QUOTA
 232 static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
 233 static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
 234 #endif
 235
 236 static struct super_operations ext2_sops = {
 237         .alloc_inode    = ext2_alloc_inode,
 238         .destroy_inode  = ext2_destroy_inode,
 239         .read_inode     = ext2_read_inode,
 240         .write_inode    = ext2_write_inode,
 241         .put_inode      = ext2_put_inode,
 242         .delete_inode   = ext2_delete_inode,
 243         .put_super      = ext2_put_super,
 244         .write_super    = ext2_write_super,
 245         .statfs         = ext2_statfs,
 246         .remount_fs     = ext2_remount,
 247         .clear_inode    = ext2_clear_inode,
 248         .show_options   = ext2_show_options,
 249 #ifdef CONFIG_QUOTA
 250         .quota_read     = ext2_quota_read,
 251         .quota_write    = ext2_quota_write,
 252 #endif
 253 };
 254
 255 static struct dentry *ext2_get_dentry(struct super_block *sb, void *vobjp)
 256 {
 257         __u32 *objp = vobjp;
 258         unsigned long ino = objp[0];
 259         __u32 generation = objp[1];
 260         struct inode *inode;
 261         struct dentry *result;
 262
 263         if (ino != EXT2_ROOT_INO && ino < EXT2_FIRST_INO(sb))
 264                 return ERR_PTR(-ESTALE);
 265         if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
 266                 return ERR_PTR(-ESTALE);
 267
 268         /* iget isn't really right if the inode is currently unallocated!!
 269          * ext2_read_inode currently does appropriate checks, but
 270          * it might be "neater" to call ext2_get_inode first and check
 271          * if the inode is valid.....
 272          */
 273         inode = iget(sb, ino);
 274         if (inode == NULL)
 275                 return ERR_PTR(-ENOMEM);
 276         if (is_bad_inode(inode)
 277             || (generation && inode->i_generation != generation)
 278                 ) {
 279                 /* we didn't find the right inode.. */
 280                 iput(inode);
 281                 return ERR_PTR(-ESTALE);
 282         }
 283         /* now to find a dentry.
 284          * If possible, get a well-connected one
 285          */
 286         result = d_alloc_anon(inode);
 287         if (!result) {
 288                 iput(inode);
 289                 return ERR_PTR(-ENOMEM);
 290         }
 291         return result;
 292 }
 293
 294
 295 /* Yes, most of these are left as NULL!!
 296  * A NULL value implies the default, which works with ext2-like file
 297  * systems, but can be improved upon.
 298  * Currently only get_parent is required.
 299  */
 300 static struct export_operations ext2_export_ops = {
 301         .get_parent = ext2_get_parent,
 302         .get_dentry = ext2_get_dentry,
 303 };
 304
 305 static unsigned long get_sb_block(void **data)
 306 {
 307         unsigned long   sb_block;
 308         char            *options = (char *) *data;
 309
 310         if (!options || strncmp(options, "sb=", 3) != 0)
 311                 return 1;       /* Default location */
 312         options += 3;
 313         sb_block = simple_strtoul(options, &options, 0);
 314         if (*options && *options != ',') {
 315                 printk("EXT2-fs: Invalid sb specification: %s\n",
 316                        (char *) *data);
 317                 return 1;
 318         }
 319         if (*options == ',')
 320                 options++;
 321         *data = (void *) options;
 322         return sb_block;
 323 }
 324
 325 enum {
 326         Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
 327         Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic,
 328         Opt_err_ro, Opt_nouid32, Opt_nocheck, Opt_debug,
 329         Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
 330         Opt_acl, Opt_noacl, Opt_xip, Opt_ignore, Opt_err, Opt_quota,
 331         Opt_usrquota, Opt_grpquota, Opt_tagxid
 332 };
 333
 334 static match_table_t tokens = {
 335         {Opt_bsd_df, "bsddf"},
 336         {Opt_minix_df, "minixdf"},
 337         {Opt_grpid, "grpid"},
 338         {Opt_grpid, "bsdgroups"},
 339         {Opt_nogrpid, "nogrpid"},
 340         {Opt_nogrpid, "sysvgroups"},
 341         {Opt_resgid, "resgid=%u"},
 342         {Opt_resuid, "resuid=%u"},
 343         {Opt_sb, "sb=%u"},
 344         {Opt_err_cont, "errors=continue"},
 345         {Opt_err_panic, "errors=panic"},
 346         {Opt_err_ro, "errors=remount-ro"},
 347         {Opt_nouid32, "nouid32"},
 348         {Opt_nocheck, "check=none"},
 349         {Opt_nocheck, "nocheck"},
 350         {Opt_debug, "debug"},
 351         {Opt_oldalloc, "oldalloc"},
 352         {Opt_orlov, "orlov"},
 353         {Opt_nobh, "nobh"},
 354         {Opt_user_xattr, "user_xattr"},
 355         {Opt_nouser_xattr, "nouser_xattr"},
 356         {Opt_acl, "acl"},
 357         {Opt_noacl, "noacl"},
 358         {Opt_xip, "xip"},
 359         {Opt_tagxid, "tagxid"},
 360         {Opt_grpquota, "grpquota"},
 361         {Opt_ignore, "noquota"},
 362         {Opt_quota, "quota"},
 363         {Opt_usrquota, "usrquota"},
 364         {Opt_err, NULL}
 365 };
 366
 367 static int parse_options (char * options,
 368                           struct ext2_sb_info *sbi)
 369 {
 370         char * p;
 371         substring_t args[MAX_OPT_ARGS];
 372         unsigned long kind = EXT2_MOUNT_ERRORS_CONT;
 373         int option;
 374
 375         if (!options)
 376                 return 1;
 377
 378         while ((p = strsep (&options, ",")) != NULL) {
 379                 int token;
 380                 if (!*p)
 381                         continue;
 382
 383                 token = match_token(p, tokens, args);
 384                 switch (token) {
 385                 case Opt_bsd_df:
 386                         clear_opt (sbi->s_mount_opt, MINIX_DF);
 387                         break;
 388                 case Opt_minix_df:
 389                         set_opt (sbi->s_mount_opt, MINIX_DF);
 390                         break;
 391                 case Opt_grpid:
 392                         set_opt (sbi->s_mount_opt, GRPID);
 393                         break;
 394                 case Opt_nogrpid:
 395                         clear_opt (sbi->s_mount_opt, GRPID);
 396                         break;
 397                 case Opt_resuid:
 398                         if (match_int(&args[0], &option))
 399                                 return 0;
 400                         sbi->s_resuid = option;
 401                         break;
 402                 case Opt_resgid:
 403                         if (match_int(&args[0], &option))
 404                                 return 0;
 405                         sbi->s_resgid = option;
 406                         break;
 407                 case Opt_sb:
 408                         /* handled by get_sb_block() instead of here */
 409                         /* *sb_block = match_int(&args[0]); */
 410                         break;
 411                 case Opt_err_panic:
 412                         kind = EXT2_MOUNT_ERRORS_PANIC;
 413                         break;
 414                 case Opt_err_ro:
 415                         kind = EXT2_MOUNT_ERRORS_RO;
 416                         break;
 417                 case Opt_err_cont:
 418                         kind = EXT2_MOUNT_ERRORS_CONT;
 419                         break;
 420                 case Opt_nouid32:
 421                         set_opt (sbi->s_mount_opt, NO_UID32);
 422                         break;
 423 #ifndef CONFIG_INOXID_NONE
 424                 case Opt_tagxid:
 425                         set_opt (sbi->s_mount_opt, TAGXID);
 426                         break;
 427 #endif
 428                 case Opt_nocheck:
 429                         clear_opt (sbi->s_mount_opt, CHECK);
 430                         break;
 431                 case Opt_debug:
 432                         set_opt (sbi->s_mount_opt, DEBUG);
 433                         break;
 434                 case Opt_oldalloc:
 435                         set_opt (sbi->s_mount_opt, OLDALLOC);
 436                         break;
 437                 case Opt_orlov:
 438                         clear_opt (sbi->s_mount_opt, OLDALLOC);
 439                         break;
 440                 case Opt_nobh:
 441                         set_opt (sbi->s_mount_opt, NOBH);
 442                         break;
 443 #ifdef CONFIG_EXT2_FS_XATTR
 444                 case Opt_user_xattr:
 445                         set_opt (sbi->s_mount_opt, XATTR_USER);
 446                         break;
 447                 case Opt_nouser_xattr:
 448                         clear_opt (sbi->s_mount_opt, XATTR_USER);
 449                         break;
 450 #else
 451                 case Opt_user_xattr:
 452                 case Opt_nouser_xattr:
 453                         printk("EXT2 (no)user_xattr options not supported\n");
 454                         break;
 455 #endif
 456 #ifdef CONFIG_EXT2_FS_POSIX_ACL
 457                 case Opt_acl:
 458                         set_opt(sbi->s_mount_opt, POSIX_ACL);
 459                         break;
 460                 case Opt_noacl:
 461                         clear_opt(sbi->s_mount_opt, POSIX_ACL);
 462                         break;
 463 #else
 464                 case Opt_acl:
 465                 case Opt_noacl:
 466                         printk("EXT2 (no)acl options not supported\n");
 467                         break;
 468 #endif
 469                 case Opt_xip:
 470 #ifdef CONFIG_EXT2_FS_XIP
 471                         set_opt (sbi->s_mount_opt, XIP);
 472 #else
 473                         printk("EXT2 xip option not supported\n");
 474 #endif
 475                         break;
 476
 477 #if defined(CONFIG_QUOTA)
 478                 case Opt_quota:
 479                 case Opt_usrquota:
 480                         set_opt(sbi->s_mount_opt, USRQUOTA);
 481                         break;
 482
 483                 case Opt_grpquota:
 484                         set_opt(sbi->s_mount_opt, GRPQUOTA);
 485                         break;
 486 #else
 487                 case Opt_quota:
 488                 case Opt_usrquota:
 489                 case Opt_grpquota:
 490                         printk(KERN_ERR
 491                                 "EXT2-fs: quota operations not supported.\n");
 492
 493                         break;
 494 #endif
 495
 496                 case Opt_ignore:
 497                         break;
 498                 default:
 499                         return 0;
 500                 }
 501         }
 502         sbi->s_mount_opt |= kind;
 503         return 1;
 504 }
 505
 506 static int ext2_setup_super (struct super_block * sb,
 507                               struct ext2_super_block * es,
 508                               int read_only)
 509 {
 510         int res = 0;
 511         struct ext2_sb_info *sbi = EXT2_SB(sb);
 512
 513         if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
 514                 printk ("EXT2-fs warning: revision level too high, "
 515                         "forcing read-only mode\n");
 516                 res = MS_RDONLY;
 517         }
 518         if (read_only)
 519                 return res;
 520         if (!(sbi->s_mount_state & EXT2_VALID_FS))
 521                 printk ("EXT2-fs warning: mounting unchecked fs, "
 522                         "running e2fsck is recommended\n");
 523         else if ((sbi->s_mount_state & EXT2_ERROR_FS))
 524                 printk ("EXT2-fs warning: mounting fs with errors, "
 525                         "running e2fsck is recommended\n");
 526         else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 527                  le16_to_cpu(es->s_mnt_count) >=
 528                  (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
 529                 printk ("EXT2-fs warning: maximal mount count reached, "
 530                         "running e2fsck is recommended\n");
 531         else if (le32_to_cpu(es->s_checkinterval) &&
 532                 (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
 533                 printk ("EXT2-fs warning: checktime reached, "
 534                         "running e2fsck is recommended\n");
 535         if (!le16_to_cpu(es->s_max_mnt_count))
 536                 es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
 537         es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
 538         ext2_write_super(sb);
 539         if (test_opt (sb, DEBUG))
 540                 printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
 541                         "bpg=%lu, ipg=%lu, mo=%04lx]\n",
 542                         EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
 543                         sbi->s_frag_size,
 544                         sbi->s_groups_count,
 545                         EXT2_BLOCKS_PER_GROUP(sb),
 546                         EXT2_INODES_PER_GROUP(sb),
 547                         sbi->s_mount_opt);
 548         return res;
 549 }
 550
 551 static int ext2_check_descriptors (struct super_block * sb)
 552 {
 553         int i;
 554         int desc_block = 0;
 555         struct ext2_sb_info *sbi = EXT2_SB(sb);
 556         unsigned long block = le32_to_cpu(sbi->s_es->s_first_data_block);
 557         struct ext2_group_desc * gdp = NULL;
 558
 559         ext2_debug ("Checking group descriptors");
 560
 561         for (i = 0; i < sbi->s_groups_count; i++)
 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) < block ||
 566                     le32_to_cpu(gdp->bg_block_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 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) < block ||
 575                     le32_to_cpu(gdp->bg_inode_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
 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) < block ||
 584                     le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
 585                     block + EXT2_BLOCKS_PER_GROUP(sb))
 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                 block += EXT2_BLOCKS_PER_GROUP(sb);
 594                 gdp++;
 595         }
 596         return 1;
 597 }
 598
 599 #define log2(n) ffz(~(n))
 600
 601 /*
 602  * Maximal file size.  There is a direct, and {,double-,triple-}indirect
 603  * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
 604  * We need to be 1 filesystem block less than the 2^32 sector limit.
 605  */
 606 static loff_t ext2_max_size(int bits)
 607 {
 608         loff_t res = EXT2_NDIR_BLOCKS;
 609         /* This constant is calculated to be the largest file size for a
 610          * dense, 4k-blocksize file such that the total number of
 611          * sectors in the file, including data and all indirect blocks,
 612          * does not exceed 2^32. */
 613         const loff_t upper_limit = 0x1ff7fffd000LL;
 614
 615         res += 1LL << (bits-2);
 616         res += 1LL << (2*(bits-2));
 617         res += 1LL << (3*(bits-2));
 618         res <<= bits;
 619         if (res > upper_limit)
 620                 res = upper_limit;
 621         return res;
 622 }
 623
 624 static unsigned long descriptor_loc(struct super_block *sb,
 625                                     unsigned long logic_sb_block,
 626                                     int nr)
 627 {
 628         struct ext2_sb_info *sbi = EXT2_SB(sb);
 629         unsigned long bg, first_data_block, first_meta_bg;
 630         int has_super = 0;
 631
 632         first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
 633         first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
 634
 635         if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
 636             nr < first_meta_bg)
 637                 return (logic_sb_block + nr + 1);
 638         bg = sbi->s_desc_per_block * nr;
 639         if (ext2_bg_has_super(sb, bg))
 640                 has_super = 1;
 641         return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
 642 }
 643
 644 static int ext2_fill_super(struct super_block *sb, void *data, int silent)
 645 {
 646         struct buffer_head * bh;
 647         struct ext2_sb_info * sbi;
 648         struct ext2_super_block * es;
 649         struct inode *root;
 650         unsigned long block;
 651         unsigned long sb_block = get_sb_block(&data);
 652         unsigned long logic_sb_block;
 653         unsigned long offset = 0;
 654         unsigned long def_mount_opts;
 655         int blocksize = BLOCK_SIZE;
 656         int db_count;
 657         int i, j;
 658         __le32 features;
 659
 660         sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
 661         if (!sbi)
 662                 return -ENOMEM;
 663         sb->s_fs_info = sbi;
 664         memset(sbi, 0, sizeof(*sbi));
 665
 666         /*
 667          * See what the current blocksize for the device is, and
 668          * use that as the blocksize.  Otherwise (or if the blocksize
 669          * is smaller than the default) use the default.
 670          * This is important for devices that have a hardware
 671          * sectorsize that is larger than the default.
 672          */
 673         blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
 674         if (!blocksize) {
 675                 printk ("EXT2-fs: unable to set blocksize\n");
 676                 goto failed_sbi;
 677         }
 678
 679         /*
 680          * If the superblock doesn't start on a hardware sector boundary,
 681          * calculate the offset.
 682          */
 683         if (blocksize != BLOCK_SIZE) {
 684                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 685                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 686         } else {
 687                 logic_sb_block = sb_block;
 688         }
 689
 690         if (!(bh = sb_bread(sb, logic_sb_block))) {
 691                 printk ("EXT2-fs: unable to read superblock\n");
 692                 goto failed_sbi;
 693         }
 694         /*
 695          * Note: s_es must be initialized as soon as possible because
 696          *       some ext2 macro-instructions depend on its value
 697          */
 698         es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 699         sbi->s_es = es;
 700         sb->s_magic = le16_to_cpu(es->s_magic);
 701
 702         if (sb->s_magic != EXT2_SUPER_MAGIC)
 703                 goto cantfind_ext2;
 704
 705         /* Set defaults before we parse the mount options */
 706         def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 707         if (def_mount_opts & EXT2_DEFM_DEBUG)
 708                 set_opt(sbi->s_mount_opt, DEBUG);
 709         if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
 710                 set_opt(sbi->s_mount_opt, GRPID);
 711         if (def_mount_opts & EXT2_DEFM_UID16)
 712                 set_opt(sbi->s_mount_opt, NO_UID32);
 713         if (def_mount_opts & EXT2_DEFM_XATTR_USER)
 714                 set_opt(sbi->s_mount_opt, XATTR_USER);
 715         if (def_mount_opts & EXT2_DEFM_ACL)
 716                 set_opt(sbi->s_mount_opt, POSIX_ACL);
 717
 718         if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
 719                 set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 720         else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
 721                 set_opt(sbi->s_mount_opt, ERRORS_RO);
 722
 723         sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
 724         sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
 725
 726         if (!parse_options ((char *) data, sbi))
 727                 goto failed_mount;
 728
 729         if (EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_TAGXID)
 730                 sb->s_flags |= MS_TAGXID;
 731         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
 732                 ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
 733                  MS_POSIXACL : 0);
 734
 735         ext2_xip_verify_sb(sb); /* see if bdev supports xip, unset
 736                                     EXT2_MOUNT_XIP if not */
 737
 738         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
 739             (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
 740              EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
 741              EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
 742                 printk("EXT2-fs warning: feature flags set on rev 0 fs, "
 743                        "running e2fsck is recommended\n");
 744         /*
 745          * Check feature flags regardless of the revision level, since we
 746          * previously didn't change the revision level when setting the flags,
 747          * so there is a chance incompat flags are set on a rev 0 filesystem.
 748          */
 749         features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
 750         if (features) {
 751                 printk("EXT2-fs: %s: couldn't mount because of "
 752                        "unsupported optional features (%x).\n",
 753                        sb->s_id, le32_to_cpu(features));
 754                 goto failed_mount;
 755         }
 756         if (!(sb->s_flags & MS_RDONLY) &&
 757             (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
 758                 printk("EXT2-fs: %s: couldn't mount RDWR because of "
 759                        "unsupported optional features (%x).\n",
 760                        sb->s_id, le32_to_cpu(features));
 761                 goto failed_mount;
 762         }
 763
 764         blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
 765
 766         if ((ext2_use_xip(sb)) && ((blocksize != PAGE_SIZE) ||
 767                                   (sb->s_blocksize != blocksize))) {
 768                 if (!silent)
 769                         printk("XIP: Unsupported blocksize\n");
 770                 goto failed_mount;
 771         }
 772
 773         /* If the blocksize doesn't match, re-read the thing.. */
 774         if (sb->s_blocksize != blocksize) {
 775                 brelse(bh);
 776
 777                 if (!sb_set_blocksize(sb, blocksize)) {
 778                         printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
 779                         goto failed_sbi;
 780                 }
 781
 782                 logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
 783                 offset = (sb_block*BLOCK_SIZE) % blocksize;
 784                 bh = sb_bread(sb, logic_sb_block);
 785                 if(!bh) {
 786                         printk("EXT2-fs: Couldn't read superblock on "
 787                                "2nd try.\n");
 788                         goto failed_sbi;
 789                 }
 790                 es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
 791                 sbi->s_es = es;
 792                 if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
 793                         printk ("EXT2-fs: Magic mismatch, very weird !\n");
 794                         goto failed_mount;
 795                 }
 796         }
 797
 798         sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
 799
 800         if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
 801                 sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
 802                 sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
 803         } else {
 804                 sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 805                 sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
 806                 if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
 807                     (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
 808                     (sbi->s_inode_size > blocksize)) {
 809                         printk ("EXT2-fs: unsupported inode size: %d\n",
 810                                 sbi->s_inode_size);
 811                         goto failed_mount;
 812                 }
 813         }
 814
 815         sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
 816                                    le32_to_cpu(es->s_log_frag_size);
 817         if (sbi->s_frag_size == 0)
 818                 goto cantfind_ext2;
 819         sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
 820
 821         sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
 822         sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
 823         sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
 824
 825         if (EXT2_INODE_SIZE(sb) == 0)
 826                 goto cantfind_ext2;
 827         sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
 828         if (sbi->s_inodes_per_block == 0)
 829                 goto cantfind_ext2;
 830         sbi->s_itb_per_group = sbi->s_inodes_per_group /
 831                                         sbi->s_inodes_per_block;
 832         sbi->s_desc_per_block = sb->s_blocksize /
 833                                         sizeof (struct ext2_group_desc);
 834         sbi->s_sbh = bh;
 835         sbi->s_mount_state = le16_to_cpu(es->s_state);
 836         sbi->s_addr_per_block_bits =
 837                 log2 (EXT2_ADDR_PER_BLOCK(sb));
 838         sbi->s_desc_per_block_bits =
 839                 log2 (EXT2_DESC_PER_BLOCK(sb));
 840
 841         if (sb->s_magic != EXT2_SUPER_MAGIC)
 842                 goto cantfind_ext2;
 843
 844         if (sb->s_blocksize != bh->b_size) {
 845                 if (!silent)
 846                         printk ("VFS: Unsupported blocksize on dev "
 847                                 "%s.\n", sb->s_id);
 848                 goto failed_mount;
 849         }
 850
 851         if (sb->s_blocksize != sbi->s_frag_size) {
 852                 printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
 853                         sbi->s_frag_size, sb->s_blocksize);
 854                 goto failed_mount;
 855         }
 856
 857         if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
 858                 printk ("EXT2-fs: #blocks per group too big: %lu\n",
 859                         sbi->s_blocks_per_group);
 860                 goto failed_mount;
 861         }
 862         if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
 863                 printk ("EXT2-fs: #fragments per group too big: %lu\n",
 864                         sbi->s_frags_per_group);
 865                 goto failed_mount;
 866         }
 867         if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
 868                 printk ("EXT2-fs: #inodes per group too big: %lu\n",
 869                         sbi->s_inodes_per_group);
 870                 goto failed_mount;
 871         }
 872
 873         if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
 874                 goto cantfind_ext2;
 875         sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
 876                                         le32_to_cpu(es->s_first_data_block) +
 877                                        EXT2_BLOCKS_PER_GROUP(sb) - 1) /
 878                                        EXT2_BLOCKS_PER_GROUP(sb);
 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         percpu_counter_init(&sbi->s_freeblocks_counter);
 887         percpu_counter_init(&sbi->s_freeinodes_counter);
 888         percpu_counter_init(&sbi->s_dirs_counter);
 889         bgl_lock_init(&sbi->s_blockgroup_lock);
 890         sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
 891                                GFP_KERNEL);
 892         if (!sbi->s_debts) {
 893                 printk ("EXT2-fs: not enough memory\n");
 894                 goto failed_mount_group_desc;
 895         }
 896         memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
 897         for (i = 0; i < db_count; i++) {
 898                 block = descriptor_loc(sb, logic_sb_block, i);
 899                 sbi->s_group_desc[i] = sb_bread(sb, block);
 900                 if (!sbi->s_group_desc[i]) {
 901                         for (j = 0; j < i; j++)
 902                                 brelse (sbi->s_group_desc[j]);
 903                         printk ("EXT2-fs: unable to read group descriptors\n");
 904                         goto failed_mount_group_desc;
 905                 }
 906         }
 907         if (!ext2_check_descriptors (sb)) {
 908                 printk ("EXT2-fs: group descriptors corrupted!\n");
 909                 db_count = i;
 910                 goto failed_mount2;
 911         }
 912         sbi->s_gdb_count = db_count;
 913         get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 914         spin_lock_init(&sbi->s_next_gen_lock);
 915         /*
 916          * set up enough so that it can read an inode
 917          */
 918         sb->s_op = &ext2_sops;
 919         sb->s_export_op = &ext2_export_ops;
 920         sb->s_xattr = ext2_xattr_handlers;
 921         root = iget(sb, EXT2_ROOT_INO);
 922         sb->s_root = d_alloc_root(root);
 923         if (!sb->s_root) {
 924                 iput(root);
 925                 printk(KERN_ERR "EXT2-fs: get root inode failed\n");
 926                 goto failed_mount2;
 927         }
 928         if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
 929                 dput(sb->s_root);
 930                 sb->s_root = NULL;
 931                 printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
 932                 goto failed_mount2;
 933         }
 934         if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
 935                 ext2_warning(sb, __FUNCTION__,
 936                         "mounting ext3 filesystem as ext2");
 937         ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
 938         percpu_counter_mod(&sbi->s_freeblocks_counter,
 939                                 ext2_count_free_blocks(sb));
 940         percpu_counter_mod(&sbi->s_freeinodes_counter,
 941                                 ext2_count_free_inodes(sb));
 942         percpu_counter_mod(&sbi->s_dirs_counter,
 943                                 ext2_count_dirs(sb));
 944         return 0;
 945
 946 cantfind_ext2:
 947         if (!silent)
 948                 printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
 949                        sb->s_id);
 950         goto failed_mount;
 951
 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         if ((sbi->s_mount_opt & EXT2_MOUNT_TAGXID) &&
1041                 !(sb->s_flags & MS_TAGXID)) {
1042                 printk("EXT2-fs: %s: tagxid not permitted on remount.\n",
1043                        sb->s_id);
1044                 return -EINVAL;
1045         }
1046
1047         sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
1048                 ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
1049
1050         es = sbi->s_es;
1051         if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
1052             (old_mount_opt & EXT2_MOUNT_XIP)) &&
1053             invalidate_inodes(sb))
1054                 ext2_warning(sb, __FUNCTION__, "busy inodes while remounting "\
1055                              "xip remain in cache (no functional problem)");
1056         if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
1057                 return 0;
1058         if (*flags & MS_RDONLY) {
1059                 if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
1060                     !(sbi->s_mount_state & EXT2_VALID_FS))
1061                         return 0;
1062                 /*
1063                  * OK, we are remounting a valid rw partition rdonly, so set
1064                  * the rdonly flag and then mark the partition as valid again.
1065                  */
1066                 es->s_state = cpu_to_le16(sbi->s_mount_state);
1067                 es->s_mtime = cpu_to_le32(get_seconds());
1068         } else {
1069                 __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
1070                                                ~EXT2_FEATURE_RO_COMPAT_SUPP);
1071                 if (ret) {
1072                         printk("EXT2-fs: %s: couldn't remount RDWR because of "
1073                                "unsupported optional features (%x).\n",
1074                                sb->s_id, le32_to_cpu(ret));
1075                         err = -EROFS;
1076                         goto restore_opts;
1077                 }
1078                 /*
1079                  * Mounting a RDONLY partition read-write, so reread and
1080                  * store the current valid flag.  (It may have been changed
1081                  * by e2fsck since we originally mounted the partition.)
1082                  */
1083                 sbi->s_mount_state = le16_to_cpu(es->s_state);
1084                 if (!ext2_setup_super (sb, es, 0))
1085                         sb->s_flags &= ~MS_RDONLY;
1086         }
1087         ext2_sync_super(sb, es);
1088         return 0;
1089 restore_opts:
1090         sbi->s_mount_opt = old_opts.s_mount_opt;
1091         sbi->s_resuid = old_opts.s_resuid;
1092         sbi->s_resgid = old_opts.s_resgid;
1093         sb->s_flags = old_sb_flags;
1094         return err;
1095 }
1096
1097 static int ext2_statfs (struct super_block * sb, struct kstatfs * buf)
1098 {
1099         struct ext2_sb_info *sbi = EXT2_SB(sb);
1100         unsigned long overhead;
1101         int i;
1102
1103         if (test_opt (sb, MINIX_DF))
1104                 overhead = 0;
1105         else {
1106                 /*
1107                  * Compute the overhead (FS structures)
1108                  */
1109
1110                 /*
1111                  * All of the blocks before first_data_block are
1112                  * overhead
1113                  */
1114                 overhead = le32_to_cpu(sbi->s_es->s_first_data_block);
1115
1116                 /*
1117                  * Add the overhead attributed to the superblock and
1118                  * block group descriptors.  If the sparse superblocks
1119                  * feature is turned on, then not all groups have this.
1120                  */
1121                 for (i = 0; i < sbi->s_groups_count; i++)
1122                         overhead += ext2_bg_has_super(sb, i) +
1123                                 ext2_bg_num_gdb(sb, i);
1124
1125                 /*
1126                  * Every block group has an inode bitmap, a block
1127                  * bitmap, and an inode table.
1128                  */
1129                 overhead += (sbi->s_groups_count *
1130                              (2 + sbi->s_itb_per_group));
1131         }
1132
1133         buf->f_type = EXT2_SUPER_MAGIC;
1134         buf->f_bsize = sb->s_blocksize;
1135         buf->f_blocks = le32_to_cpu(sbi->s_es->s_blocks_count) - overhead;
1136         buf->f_bfree = ext2_count_free_blocks(sb);
1137         buf->f_bavail = buf->f_bfree - le32_to_cpu(sbi->s_es->s_r_blocks_count);
1138         if (buf->f_bfree < le32_to_cpu(sbi->s_es->s_r_blocks_count))
1139                 buf->f_bavail = 0;
1140         buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);
1141         buf->f_ffree = ext2_count_free_inodes (sb);
1142         buf->f_namelen = EXT2_NAME_LEN;
1143         return 0;
1144 }
1145
1146 static struct super_block *ext2_get_sb(struct file_system_type *fs_type,
1147         int flags, const char *dev_name, void *data)
1148 {
1149         return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
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(&inode->i_mutex);
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)