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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/ext2/super.c
downloadop-kernel-dev-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip
op-kernel-dev-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'fs/ext2/super.c')
-rw-r--r--fs/ext2/super.c1161
1 files changed, 1161 insertions, 0 deletions
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
new file mode 100644
index 0000000..37ca77a
--- /dev/null
+++ b/fs/ext2/super.c
@@ -0,0 +1,1161 @@
+/*
+ * linux/fs/ext2/super.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ * from
+ *
+ * linux/fs/minix/inode.c
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ * Big-endian to little-endian byte-swapping/bitmaps by
+ * David S. Miller (davem@caip.rutgers.edu), 1995
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <linux/parser.h>
+#include <linux/random.h>
+#include <linux/buffer_head.h>
+#include <linux/smp_lock.h>
+#include <linux/vfs.h>
+#include <asm/uaccess.h>
+#include "ext2.h"
+#include "xattr.h"
+#include "acl.h"
+
+static void ext2_sync_super(struct super_block *sb,
+ struct ext2_super_block *es);
+static int ext2_remount (struct super_block * sb, int * flags, char * data);
+static int ext2_statfs (struct super_block * sb, struct kstatfs * buf);
+
+void ext2_error (struct super_block * sb, const char * function,
+ const char * fmt, ...)
+{
+ va_list args;
+ struct ext2_sb_info *sbi = EXT2_SB(sb);
+ struct ext2_super_block *es = sbi->s_es;
+
+ if (!(sb->s_flags & MS_RDONLY)) {
+ sbi->s_mount_state |= EXT2_ERROR_FS;
+ es->s_state =
+ cpu_to_le16(le16_to_cpu(es->s_state) | EXT2_ERROR_FS);
+ ext2_sync_super(sb, es);
+ }
+
+ va_start(args, fmt);
+ printk(KERN_CRIT "EXT2-fs error (device %s): %s: ",sb->s_id, function);
+ vprintk(fmt, args);
+ printk("\n");
+ va_end(args);
+
+ if (test_opt(sb, ERRORS_PANIC))
+ panic("EXT2-fs panic from previous error\n");
+ if (test_opt(sb, ERRORS_RO)) {
+ printk("Remounting filesystem read-only\n");
+ sb->s_flags |= MS_RDONLY;
+ }
+}
+
+void ext2_warning (struct super_block * sb, const char * function,
+ const char * fmt, ...)
+{
+ va_list args;
+
+ va_start(args, fmt);
+ printk(KERN_WARNING "EXT2-fs warning (device %s): %s: ",
+ sb->s_id, function);
+ vprintk(fmt, args);
+ printk("\n");
+ va_end(args);
+}
+
+void ext2_update_dynamic_rev(struct super_block *sb)
+{
+ struct ext2_super_block *es = EXT2_SB(sb)->s_es;
+
+ if (le32_to_cpu(es->s_rev_level) > EXT2_GOOD_OLD_REV)
+ return;
+
+ ext2_warning(sb, __FUNCTION__,
+ "updating to rev %d because of new feature flag, "
+ "running e2fsck is recommended",
+ EXT2_DYNAMIC_REV);
+
+ es->s_first_ino = cpu_to_le32(EXT2_GOOD_OLD_FIRST_INO);
+ es->s_inode_size = cpu_to_le16(EXT2_GOOD_OLD_INODE_SIZE);
+ es->s_rev_level = cpu_to_le32(EXT2_DYNAMIC_REV);
+ /* leave es->s_feature_*compat flags alone */
+ /* es->s_uuid will be set by e2fsck if empty */
+
+ /*
+ * The rest of the superblock fields should be zero, and if not it
+ * means they are likely already in use, so leave them alone. We
+ * can leave it up to e2fsck to clean up any inconsistencies there.
+ */
+}
+
+static void ext2_put_super (struct super_block * sb)
+{
+ int db_count;
+ int i;
+ struct ext2_sb_info *sbi = EXT2_SB(sb);
+
+ ext2_xattr_put_super(sb);
+ if (!(sb->s_flags & MS_RDONLY)) {
+ struct ext2_super_block *es = sbi->s_es;
+
+ es->s_state = cpu_to_le16(sbi->s_mount_state);
+ ext2_sync_super(sb, es);
+ }
+ db_count = sbi->s_gdb_count;
+ for (i = 0; i < db_count; i++)
+ if (sbi->s_group_desc[i])
+ brelse (sbi->s_group_desc[i]);
+ kfree(sbi->s_group_desc);
+ kfree(sbi->s_debts);
+ percpu_counter_destroy(&sbi->s_freeblocks_counter);
+ percpu_counter_destroy(&sbi->s_freeinodes_counter);
+ percpu_counter_destroy(&sbi->s_dirs_counter);
+ brelse (sbi->s_sbh);
+ sb->s_fs_info = NULL;
+ kfree(sbi);
+
+ return;
+}
+
+static kmem_cache_t * ext2_inode_cachep;
+
+static struct inode *ext2_alloc_inode(struct super_block *sb)
+{
+ struct ext2_inode_info *ei;
+ ei = (struct ext2_inode_info *)kmem_cache_alloc(ext2_inode_cachep, SLAB_KERNEL);
+ if (!ei)
+ return NULL;
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+ ei->i_acl = EXT2_ACL_NOT_CACHED;
+ ei->i_default_acl = EXT2_ACL_NOT_CACHED;
+#endif
+ ei->vfs_inode.i_version = 1;
+ return &ei->vfs_inode;
+}
+
+static void ext2_destroy_inode(struct inode *inode)
+{
+ kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
+}
+
+static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
+{
+ struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
+
+ if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
+ SLAB_CTOR_CONSTRUCTOR) {
+ rwlock_init(&ei->i_meta_lock);
+#ifdef CONFIG_EXT2_FS_XATTR
+ init_rwsem(&ei->xattr_sem);
+#endif
+ inode_init_once(&ei->vfs_inode);
+ }
+}
+
+static int init_inodecache(void)
+{
+ ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
+ sizeof(struct ext2_inode_info),
+ 0, SLAB_RECLAIM_ACCOUNT,
+ init_once, NULL);
+ if (ext2_inode_cachep == NULL)
+ return -ENOMEM;
+ return 0;
+}
+
+static void destroy_inodecache(void)
+{
+ if (kmem_cache_destroy(ext2_inode_cachep))
+ printk(KERN_INFO "ext2_inode_cache: not all structures were freed\n");
+}
+
+static void ext2_clear_inode(struct inode *inode)
+{
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+ struct ext2_inode_info *ei = EXT2_I(inode);
+
+ if (ei->i_acl && ei->i_acl != EXT2_ACL_NOT_CACHED) {
+ posix_acl_release(ei->i_acl);
+ ei->i_acl = EXT2_ACL_NOT_CACHED;
+ }
+ if (ei->i_default_acl && ei->i_default_acl != EXT2_ACL_NOT_CACHED) {
+ posix_acl_release(ei->i_default_acl);
+ ei->i_default_acl = EXT2_ACL_NOT_CACHED;
+ }
+#endif
+ if (!is_bad_inode(inode))
+ ext2_discard_prealloc(inode);
+}
+
+
+#ifdef CONFIG_QUOTA
+static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data, size_t len, loff_t off);
+static ssize_t ext2_quota_write(struct super_block *sb, int type, const char *data, size_t len, loff_t off);
+#endif
+
+static struct super_operations ext2_sops = {
+ .alloc_inode = ext2_alloc_inode,
+ .destroy_inode = ext2_destroy_inode,
+ .read_inode = ext2_read_inode,
+ .write_inode = ext2_write_inode,
+ .delete_inode = ext2_delete_inode,
+ .put_super = ext2_put_super,
+ .write_super = ext2_write_super,
+ .statfs = ext2_statfs,
+ .remount_fs = ext2_remount,
+ .clear_inode = ext2_clear_inode,
+#ifdef CONFIG_QUOTA
+ .quota_read = ext2_quota_read,
+ .quota_write = ext2_quota_write,
+#endif
+};
+
+/* Yes, most of these are left as NULL!!
+ * A NULL value implies the default, which works with ext2-like file
+ * systems, but can be improved upon.
+ * Currently only get_parent is required.
+ */
+struct dentry *ext2_get_parent(struct dentry *child);
+static struct export_operations ext2_export_ops = {
+ .get_parent = ext2_get_parent,
+};
+
+static unsigned long get_sb_block(void **data)
+{
+ unsigned long sb_block;
+ char *options = (char *) *data;
+
+ if (!options || strncmp(options, "sb=", 3) != 0)
+ return 1; /* Default location */
+ options += 3;
+ sb_block = simple_strtoul(options, &options, 0);
+ if (*options && *options != ',') {
+ printk("EXT2-fs: Invalid sb specification: %s\n",
+ (char *) *data);
+ return 1;
+ }
+ if (*options == ',')
+ options++;
+ *data = (void *) options;
+ return sb_block;
+}
+
+enum {
+ Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
+ Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
+ Opt_nouid32, Opt_check, Opt_nocheck, Opt_debug, Opt_oldalloc, Opt_orlov, Opt_nobh,
+ Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
+ Opt_ignore, Opt_err,
+};
+
+static match_table_t tokens = {
+ {Opt_bsd_df, "bsddf"},
+ {Opt_minix_df, "minixdf"},
+ {Opt_grpid, "grpid"},
+ {Opt_grpid, "bsdgroups"},
+ {Opt_nogrpid, "nogrpid"},
+ {Opt_nogrpid, "sysvgroups"},
+ {Opt_resgid, "resgid=%u"},
+ {Opt_resuid, "resuid=%u"},
+ {Opt_sb, "sb=%u"},
+ {Opt_err_cont, "errors=continue"},
+ {Opt_err_panic, "errors=panic"},
+ {Opt_err_ro, "errors=remount-ro"},
+ {Opt_nouid32, "nouid32"},
+ {Opt_nocheck, "check=none"},
+ {Opt_nocheck, "nocheck"},
+ {Opt_check, "check"},
+ {Opt_debug, "debug"},
+ {Opt_oldalloc, "oldalloc"},
+ {Opt_orlov, "orlov"},
+ {Opt_nobh, "nobh"},
+ {Opt_user_xattr, "user_xattr"},
+ {Opt_nouser_xattr, "nouser_xattr"},
+ {Opt_acl, "acl"},
+ {Opt_noacl, "noacl"},
+ {Opt_ignore, "grpquota"},
+ {Opt_ignore, "noquota"},
+ {Opt_ignore, "quota"},
+ {Opt_ignore, "usrquota"},
+ {Opt_err, NULL}
+};
+
+static int parse_options (char * options,
+ struct ext2_sb_info *sbi)
+{
+ char * p;
+ substring_t args[MAX_OPT_ARGS];
+ unsigned long kind = EXT2_MOUNT_ERRORS_CONT;
+ int option;
+
+ if (!options)
+ return 1;
+
+ while ((p = strsep (&options, ",")) != NULL) {
+ int token;
+ if (!*p)
+ continue;
+
+ token = match_token(p, tokens, args);
+ switch (token) {
+ case Opt_bsd_df:
+ clear_opt (sbi->s_mount_opt, MINIX_DF);
+ break;
+ case Opt_minix_df:
+ set_opt (sbi->s_mount_opt, MINIX_DF);
+ break;
+ case Opt_grpid:
+ set_opt (sbi->s_mount_opt, GRPID);
+ break;
+ case Opt_nogrpid:
+ clear_opt (sbi->s_mount_opt, GRPID);
+ break;
+ case Opt_resuid:
+ if (match_int(&args[0], &option))
+ return 0;
+ sbi->s_resuid = option;
+ break;
+ case Opt_resgid:
+ if (match_int(&args[0], &option))
+ return 0;
+ sbi->s_resgid = option;
+ break;
+ case Opt_sb:
+ /* handled by get_sb_block() instead of here */
+ /* *sb_block = match_int(&args[0]); */
+ break;
+ case Opt_err_panic:
+ kind = EXT2_MOUNT_ERRORS_PANIC;
+ break;
+ case Opt_err_ro:
+ kind = EXT2_MOUNT_ERRORS_RO;
+ break;
+ case Opt_err_cont:
+ kind = EXT2_MOUNT_ERRORS_CONT;
+ break;
+ case Opt_nouid32:
+ set_opt (sbi->s_mount_opt, NO_UID32);
+ break;
+ case Opt_check:
+#ifdef CONFIG_EXT2_CHECK
+ set_opt (sbi->s_mount_opt, CHECK);
+#else
+ printk("EXT2 Check option not supported\n");
+#endif
+ break;
+ case Opt_nocheck:
+ clear_opt (sbi->s_mount_opt, CHECK);
+ break;
+ case Opt_debug:
+ set_opt (sbi->s_mount_opt, DEBUG);
+ break;
+ case Opt_oldalloc:
+ set_opt (sbi->s_mount_opt, OLDALLOC);
+ break;
+ case Opt_orlov:
+ clear_opt (sbi->s_mount_opt, OLDALLOC);
+ break;
+ case Opt_nobh:
+ set_opt (sbi->s_mount_opt, NOBH);
+ break;
+#ifdef CONFIG_EXT2_FS_XATTR
+ case Opt_user_xattr:
+ set_opt (sbi->s_mount_opt, XATTR_USER);
+ break;
+ case Opt_nouser_xattr:
+ clear_opt (sbi->s_mount_opt, XATTR_USER);
+ break;
+#else
+ case Opt_user_xattr:
+ case Opt_nouser_xattr:
+ printk("EXT2 (no)user_xattr options not supported\n");
+ break;
+#endif
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+ case Opt_acl:
+ set_opt(sbi->s_mount_opt, POSIX_ACL);
+ break;
+ case Opt_noacl:
+ clear_opt(sbi->s_mount_opt, POSIX_ACL);
+ break;
+#else
+ case Opt_acl:
+ case Opt_noacl:
+ printk("EXT2 (no)acl options not supported\n");
+ break;
+#endif
+ case Opt_ignore:
+ break;
+ default:
+ return 0;
+ }
+ }
+ sbi->s_mount_opt |= kind;
+ return 1;
+}
+
+static int ext2_setup_super (struct super_block * sb,
+ struct ext2_super_block * es,
+ int read_only)
+{
+ int res = 0;
+ struct ext2_sb_info *sbi = EXT2_SB(sb);
+
+ if (le32_to_cpu(es->s_rev_level) > EXT2_MAX_SUPP_REV) {
+ printk ("EXT2-fs warning: revision level too high, "
+ "forcing read-only mode\n");
+ res = MS_RDONLY;
+ }
+ if (read_only)
+ return res;
+ if (!(sbi->s_mount_state & EXT2_VALID_FS))
+ printk ("EXT2-fs warning: mounting unchecked fs, "
+ "running e2fsck is recommended\n");
+ else if ((sbi->s_mount_state & EXT2_ERROR_FS))
+ printk ("EXT2-fs warning: mounting fs with errors, "
+ "running e2fsck is recommended\n");
+ else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
+ le16_to_cpu(es->s_mnt_count) >=
+ (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
+ printk ("EXT2-fs warning: maximal mount count reached, "
+ "running e2fsck is recommended\n");
+ else if (le32_to_cpu(es->s_checkinterval) &&
+ (le32_to_cpu(es->s_lastcheck) + le32_to_cpu(es->s_checkinterval) <= get_seconds()))
+ printk ("EXT2-fs warning: checktime reached, "
+ "running e2fsck is recommended\n");
+ if (!le16_to_cpu(es->s_max_mnt_count))
+ es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
+ es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
+ ext2_write_super(sb);
+ if (test_opt (sb, DEBUG))
+ printk ("[EXT II FS %s, %s, bs=%lu, fs=%lu, gc=%lu, "
+ "bpg=%lu, ipg=%lu, mo=%04lx]\n",
+ EXT2FS_VERSION, EXT2FS_DATE, sb->s_blocksize,
+ sbi->s_frag_size,
+ sbi->s_groups_count,
+ EXT2_BLOCKS_PER_GROUP(sb),
+ EXT2_INODES_PER_GROUP(sb),
+ sbi->s_mount_opt);
+#ifdef CONFIG_EXT2_CHECK
+ if (test_opt (sb, CHECK)) {
+ ext2_check_blocks_bitmap (sb);
+ ext2_check_inodes_bitmap (sb);
+ }
+#endif
+ return res;
+}
+
+static int ext2_check_descriptors (struct super_block * sb)
+{
+ int i;
+ int desc_block = 0;
+ struct ext2_sb_info *sbi = EXT2_SB(sb);
+ unsigned long block = le32_to_cpu(sbi->s_es->s_first_data_block);
+ struct ext2_group_desc * gdp = NULL;
+
+ ext2_debug ("Checking group descriptors");
+
+ for (i = 0; i < sbi->s_groups_count; i++)
+ {
+ if ((i % EXT2_DESC_PER_BLOCK(sb)) == 0)
+ gdp = (struct ext2_group_desc *) sbi->s_group_desc[desc_block++]->b_data;
+ if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
+ le32_to_cpu(gdp->bg_block_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
+ {
+ ext2_error (sb, "ext2_check_descriptors",
+ "Block bitmap for group %d"
+ " not in group (block %lu)!",
+ i, (unsigned long) le32_to_cpu(gdp->bg_block_bitmap));
+ return 0;
+ }
+ if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
+ le32_to_cpu(gdp->bg_inode_bitmap) >= block + EXT2_BLOCKS_PER_GROUP(sb))
+ {
+ ext2_error (sb, "ext2_check_descriptors",
+ "Inode bitmap for group %d"
+ " not in group (block %lu)!",
+ i, (unsigned long) le32_to_cpu(gdp->bg_inode_bitmap));
+ return 0;
+ }
+ if (le32_to_cpu(gdp->bg_inode_table) < block ||
+ le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
+ block + EXT2_BLOCKS_PER_GROUP(sb))
+ {
+ ext2_error (sb, "ext2_check_descriptors",
+ "Inode table for group %d"
+ " not in group (block %lu)!",
+ i, (unsigned long) le32_to_cpu(gdp->bg_inode_table));
+ return 0;
+ }
+ block += EXT2_BLOCKS_PER_GROUP(sb);
+ gdp++;
+ }
+ return 1;
+}
+
+#define log2(n) ffz(~(n))
+
+/*
+ * Maximal file size. There is a direct, and {,double-,triple-}indirect
+ * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
+ * We need to be 1 filesystem block less than the 2^32 sector limit.
+ */
+static loff_t ext2_max_size(int bits)
+{
+ loff_t res = EXT2_NDIR_BLOCKS;
+ /* This constant is calculated to be the largest file size for a
+ * dense, 4k-blocksize file such that the total number of
+ * sectors in the file, including data and all indirect blocks,
+ * does not exceed 2^32. */
+ const loff_t upper_limit = 0x1ff7fffd000LL;
+
+ res += 1LL << (bits-2);
+ res += 1LL << (2*(bits-2));
+ res += 1LL << (3*(bits-2));
+ res <<= bits;
+ if (res > upper_limit)
+ res = upper_limit;
+ return res;
+}
+
+static unsigned long descriptor_loc(struct super_block *sb,
+ unsigned long logic_sb_block,
+ int nr)
+{
+ struct ext2_sb_info *sbi = EXT2_SB(sb);
+ unsigned long bg, first_data_block, first_meta_bg;
+ int has_super = 0;
+
+ first_data_block = le32_to_cpu(sbi->s_es->s_first_data_block);
+ first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
+
+ if (!EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_META_BG) ||
+ nr < first_meta_bg)
+ return (logic_sb_block + nr + 1);
+ bg = sbi->s_desc_per_block * nr;
+ if (ext2_bg_has_super(sb, bg))
+ has_super = 1;
+ return (first_data_block + has_super + (bg * sbi->s_blocks_per_group));
+}
+
+static int ext2_fill_super(struct super_block *sb, void *data, int silent)
+{
+ struct buffer_head * bh;
+ struct ext2_sb_info * sbi;
+ struct ext2_super_block * es;
+ struct inode *root;
+ unsigned long block;
+ unsigned long sb_block = get_sb_block(&data);
+ unsigned long logic_sb_block;
+ unsigned long offset = 0;
+ unsigned long def_mount_opts;
+ int blocksize = BLOCK_SIZE;
+ int db_count;
+ int i, j;
+ __le32 features;
+
+ sbi = kmalloc(sizeof(*sbi), GFP_KERNEL);
+ if (!sbi)
+ return -ENOMEM;
+ sb->s_fs_info = sbi;
+ memset(sbi, 0, sizeof(*sbi));
+
+ /*
+ * See what the current blocksize for the device is, and
+ * use that as the blocksize. Otherwise (or if the blocksize
+ * is smaller than the default) use the default.
+ * This is important for devices that have a hardware
+ * sectorsize that is larger than the default.
+ */
+ blocksize = sb_min_blocksize(sb, BLOCK_SIZE);
+ if (!blocksize) {
+ printk ("EXT2-fs: unable to set blocksize\n");
+ goto failed_sbi;
+ }
+
+ /*
+ * If the superblock doesn't start on a hardware sector boundary,
+ * calculate the offset.
+ */
+ if (blocksize != BLOCK_SIZE) {
+ logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
+ offset = (sb_block*BLOCK_SIZE) % blocksize;
+ } else {
+ logic_sb_block = sb_block;
+ }
+
+ if (!(bh = sb_bread(sb, logic_sb_block))) {
+ printk ("EXT2-fs: unable to read superblock\n");
+ goto failed_sbi;
+ }
+ /*
+ * Note: s_es must be initialized as soon as possible because
+ * some ext2 macro-instructions depend on its value
+ */
+ es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
+ sbi->s_es = es;
+ sb->s_magic = le16_to_cpu(es->s_magic);
+
+ if (sb->s_magic != EXT2_SUPER_MAGIC)
+ goto cantfind_ext2;
+
+ /* Set defaults before we parse the mount options */
+ def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
+ if (def_mount_opts & EXT2_DEFM_DEBUG)
+ set_opt(sbi->s_mount_opt, DEBUG);
+ if (def_mount_opts & EXT2_DEFM_BSDGROUPS)
+ set_opt(sbi->s_mount_opt, GRPID);
+ if (def_mount_opts & EXT2_DEFM_UID16)
+ set_opt(sbi->s_mount_opt, NO_UID32);
+ if (def_mount_opts & EXT2_DEFM_XATTR_USER)
+ set_opt(sbi->s_mount_opt, XATTR_USER);
+ if (def_mount_opts & EXT2_DEFM_ACL)
+ set_opt(sbi->s_mount_opt, POSIX_ACL);
+
+ if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC)
+ set_opt(sbi->s_mount_opt, ERRORS_PANIC);
+ else if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_RO)
+ set_opt(sbi->s_mount_opt, ERRORS_RO);
+
+ sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
+ sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
+
+ if (!parse_options ((char *) data, sbi))
+ goto failed_mount;
+
+ sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
+ ((EXT2_SB(sb)->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ?
+ MS_POSIXACL : 0);
+
+ if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV &&
+ (EXT2_HAS_COMPAT_FEATURE(sb, ~0U) ||
+ EXT2_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
+ EXT2_HAS_INCOMPAT_FEATURE(sb, ~0U)))
+ printk("EXT2-fs warning: feature flags set on rev 0 fs, "
+ "running e2fsck is recommended\n");
+ /*
+ * Check feature flags regardless of the revision level, since we
+ * previously didn't change the revision level when setting the flags,
+ * so there is a chance incompat flags are set on a rev 0 filesystem.
+ */
+ features = EXT2_HAS_INCOMPAT_FEATURE(sb, ~EXT2_FEATURE_INCOMPAT_SUPP);
+ if (features) {
+ printk("EXT2-fs: %s: couldn't mount because of "
+ "unsupported optional features (%x).\n",
+ sb->s_id, le32_to_cpu(features));
+ goto failed_mount;
+ }
+ if (!(sb->s_flags & MS_RDONLY) &&
+ (features = EXT2_HAS_RO_COMPAT_FEATURE(sb, ~EXT2_FEATURE_RO_COMPAT_SUPP))){
+ printk("EXT2-fs: %s: couldn't mount RDWR because of "
+ "unsupported optional features (%x).\n",
+ sb->s_id, le32_to_cpu(features));
+ goto failed_mount;
+ }
+
+ blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
+
+ /* If the blocksize doesn't match, re-read the thing.. */
+ if (sb->s_blocksize != blocksize) {
+ brelse(bh);
+
+ if (!sb_set_blocksize(sb, blocksize)) {
+ printk(KERN_ERR "EXT2-fs: blocksize too small for device.\n");
+ goto failed_sbi;
+ }
+
+ logic_sb_block = (sb_block*BLOCK_SIZE) / blocksize;
+ offset = (sb_block*BLOCK_SIZE) % blocksize;
+ bh = sb_bread(sb, logic_sb_block);
+ if(!bh) {
+ printk("EXT2-fs: Couldn't read superblock on "
+ "2nd try.\n");
+ goto failed_sbi;
+ }
+ es = (struct ext2_super_block *) (((char *)bh->b_data) + offset);
+ sbi->s_es = es;
+ if (es->s_magic != cpu_to_le16(EXT2_SUPER_MAGIC)) {
+ printk ("EXT2-fs: Magic mismatch, very weird !\n");
+ goto failed_mount;
+ }
+ }
+
+ sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
+
+ if (le32_to_cpu(es->s_rev_level) == EXT2_GOOD_OLD_REV) {
+ sbi->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
+ sbi->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
+ } else {
+ sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
+ sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
+ if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
+ (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
+ (sbi->s_inode_size > blocksize)) {
+ printk ("EXT2-fs: unsupported inode size: %d\n",
+ sbi->s_inode_size);
+ goto failed_mount;
+ }
+ }
+
+ sbi->s_frag_size = EXT2_MIN_FRAG_SIZE <<
+ le32_to_cpu(es->s_log_frag_size);
+ if (sbi->s_frag_size == 0)
+ goto cantfind_ext2;
+ sbi->s_frags_per_block = sb->s_blocksize / sbi->s_frag_size;
+
+ sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
+ sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
+ sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
+
+ if (EXT2_INODE_SIZE(sb) == 0)
+ goto cantfind_ext2;
+ sbi->s_inodes_per_block = sb->s_blocksize / EXT2_INODE_SIZE(sb);
+ if (sbi->s_inodes_per_block == 0)
+ goto cantfind_ext2;
+ sbi->s_itb_per_group = sbi->s_inodes_per_group /
+ sbi->s_inodes_per_block;
+ sbi->s_desc_per_block = sb->s_blocksize /
+ sizeof (struct ext2_group_desc);
+ sbi->s_sbh = bh;
+ sbi->s_mount_state = le16_to_cpu(es->s_state);
+ sbi->s_addr_per_block_bits =
+ log2 (EXT2_ADDR_PER_BLOCK(sb));
+ sbi->s_desc_per_block_bits =
+ log2 (EXT2_DESC_PER_BLOCK(sb));
+
+ if (sb->s_magic != EXT2_SUPER_MAGIC)
+ goto cantfind_ext2;
+
+ if (sb->s_blocksize != bh->b_size) {
+ if (!silent)
+ printk ("VFS: Unsupported blocksize on dev "
+ "%s.\n", sb->s_id);
+ goto failed_mount;
+ }
+
+ if (sb->s_blocksize != sbi->s_frag_size) {
+ printk ("EXT2-fs: fragsize %lu != blocksize %lu (not supported yet)\n",
+ sbi->s_frag_size, sb->s_blocksize);
+ goto failed_mount;
+ }
+
+ if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
+ printk ("EXT2-fs: #blocks per group too big: %lu\n",
+ sbi->s_blocks_per_group);
+ goto failed_mount;
+ }
+ if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
+ printk ("EXT2-fs: #fragments per group too big: %lu\n",
+ sbi->s_frags_per_group);
+ goto failed_mount;
+ }
+ if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
+ printk ("EXT2-fs: #inodes per group too big: %lu\n",
+ sbi->s_inodes_per_group);
+ goto failed_mount;
+ }
+
+ if (EXT2_BLOCKS_PER_GROUP(sb) == 0)
+ goto cantfind_ext2;
+ sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
+ le32_to_cpu(es->s_first_data_block) +
+ EXT2_BLOCKS_PER_GROUP(sb) - 1) /
+ EXT2_BLOCKS_PER_GROUP(sb);
+ db_count = (sbi->s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
+ EXT2_DESC_PER_BLOCK(sb);
+ sbi->s_group_desc = kmalloc (db_count * sizeof (struct buffer_head *), GFP_KERNEL);
+ if (sbi->s_group_desc == NULL) {
+ printk ("EXT2-fs: not enough memory\n");
+ goto failed_mount;
+ }
+ percpu_counter_init(&sbi->s_freeblocks_counter);
+ percpu_counter_init(&sbi->s_freeinodes_counter);
+ percpu_counter_init(&sbi->s_dirs_counter);
+ bgl_lock_init(&sbi->s_blockgroup_lock);
+ sbi->s_debts = kmalloc(sbi->s_groups_count * sizeof(*sbi->s_debts),
+ GFP_KERNEL);
+ if (!sbi->s_debts) {
+ printk ("EXT2-fs: not enough memory\n");
+ goto failed_mount_group_desc;
+ }
+ memset(sbi->s_debts, 0, sbi->s_groups_count * sizeof(*sbi->s_debts));
+ for (i = 0; i < db_count; i++) {
+ block = descriptor_loc(sb, logic_sb_block, i);
+ sbi->s_group_desc[i] = sb_bread(sb, block);
+ if (!sbi->s_group_desc[i]) {
+ for (j = 0; j < i; j++)
+ brelse (sbi->s_group_desc[j]);
+ printk ("EXT2-fs: unable to read group descriptors\n");
+ goto failed_mount_group_desc;
+ }
+ }
+ if (!ext2_check_descriptors (sb)) {
+ printk ("EXT2-fs: group descriptors corrupted!\n");
+ db_count = i;
+ goto failed_mount2;
+ }
+ sbi->s_gdb_count = db_count;
+ get_random_bytes(&sbi->s_next_generation, sizeof(u32));
+ spin_lock_init(&sbi->s_next_gen_lock);
+ /*
+ * set up enough so that it can read an inode
+ */
+ sb->s_op = &ext2_sops;
+ sb->s_export_op = &ext2_export_ops;
+ sb->s_xattr = ext2_xattr_handlers;
+ root = iget(sb, EXT2_ROOT_INO);
+ sb->s_root = d_alloc_root(root);
+ if (!sb->s_root) {
+ iput(root);
+ printk(KERN_ERR "EXT2-fs: get root inode failed\n");
+ goto failed_mount2;
+ }
+ if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
+ dput(sb->s_root);
+ sb->s_root = NULL;
+ printk(KERN_ERR "EXT2-fs: corrupt root inode, run e2fsck\n");
+ goto failed_mount2;
+ }
+ if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
+ ext2_warning(sb, __FUNCTION__,
+ "mounting ext3 filesystem as ext2\n");
+ ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
+ percpu_counter_mod(&sbi->s_freeblocks_counter,
+ ext2_count_free_blocks(sb));
+ percpu_counter_mod(&sbi->s_freeinodes_counter,
+ ext2_count_free_inodes(sb));
+ percpu_counter_mod(&sbi->s_dirs_counter,
+ ext2_count_dirs(sb));
+ return 0;
+
+cantfind_ext2:
+ if (!silent)
+ printk("VFS: Can't find an ext2 filesystem on dev %s.\n",
+ sb->s_id);
+ goto failed_mount;
+
+failed_mount2:
+ for (i = 0; i < db_count; i++)
+ brelse(sbi->s_group_desc[i]);
+failed_mount_group_desc:
+ kfree(sbi->s_group_desc);
+ kfree(sbi->s_debts);
+failed_mount:
+ brelse(bh);
+failed_sbi:
+ sb->s_fs_info = NULL;
+ kfree(sbi);
+ return -EINVAL;
+}
+
+static void ext2_commit_super (struct super_block * sb,
+ struct ext2_super_block * es)
+{
+ es->s_wtime = cpu_to_le32(get_seconds());
+ mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
+ sb->s_dirt = 0;
+}
+
+static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es)
+{
+ es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
+ es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
+ es->s_wtime = cpu_to_le32(get_seconds());
+ mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
+ sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
+ sb->s_dirt = 0;
+}
+
+/*
+ * In the second extended file system, it is not necessary to
+ * write the super block since we use a mapping of the
+ * disk super block in a buffer.
+ *
+ * However, this function is still used to set the fs valid
+ * flags to 0. We need to set this flag to 0 since the fs
+ * may have been checked while mounted and e2fsck may have
+ * set s_state to EXT2_VALID_FS after some corrections.
+ */
+
+void ext2_write_super (struct super_block * sb)
+{
+ struct ext2_super_block * es;
+ lock_kernel();
+ if (!(sb->s_flags & MS_RDONLY)) {
+ es = EXT2_SB(sb)->s_es;
+
+ if (le16_to_cpu(es->s_state) & EXT2_VALID_FS) {
+ ext2_debug ("setting valid to 0\n");
+ es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) &
+ ~EXT2_VALID_FS);
+ es->s_free_blocks_count = cpu_to_le32(ext2_count_free_blocks(sb));
+ es->s_free_inodes_count = cpu_to_le32(ext2_count_free_inodes(sb));
+ es->s_mtime = cpu_to_le32(get_seconds());
+ ext2_sync_super(sb, es);
+ } else
+ ext2_commit_super (sb, es);
+ }
+ sb->s_dirt = 0;
+ unlock_kernel();
+}
+
+static int ext2_remount (struct super_block * sb, int * flags, char * data)
+{
+ struct ext2_sb_info * sbi = EXT2_SB(sb);
+ struct ext2_super_block * es;
+
+ /*
+ * Allow the "check" option to be passed as a remount option.
+ */
+ if (!parse_options (data, sbi))
+ return -EINVAL;
+
+ sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
+ ((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
+
+ es = sbi->s_es;
+ if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
+ return 0;
+ if (*flags & MS_RDONLY) {
+ if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
+ !(sbi->s_mount_state & EXT2_VALID_FS))
+ return 0;
+ /*
+ * OK, we are remounting a valid rw partition rdonly, so set
+ * the rdonly flag and then mark the partition as valid again.
+ */
+ es->s_state = cpu_to_le16(sbi->s_mount_state);
+ es->s_mtime = cpu_to_le32(get_seconds());
+ } else {
+ __le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
+ ~EXT2_FEATURE_RO_COMPAT_SUPP);
+ if (ret) {
+ printk("EXT2-fs: %s: couldn't remount RDWR because of "
+ "unsupported optional features (%x).\n",
+ sb->s_id, le32_to_cpu(ret));
+ return -EROFS;
+ }
+ /*
+ * Mounting a RDONLY partition read-write, so reread and
+ * store the current valid flag. (It may have been changed
+ * by e2fsck since we originally mounted the partition.)
+ */
+ sbi->s_mount_state = le16_to_cpu(es->s_state);
+ if (!ext2_setup_super (sb, es, 0))
+ sb->s_flags &= ~MS_RDONLY;
+ }
+ ext2_sync_super(sb, es);
+ return 0;
+}
+
+static int ext2_statfs (struct super_block * sb, struct kstatfs * buf)
+{
+ struct ext2_sb_info *sbi = EXT2_SB(sb);
+ unsigned long overhead;
+ int i;
+
+ if (test_opt (sb, MINIX_DF))
+ overhead = 0;
+ else {
+ /*
+ * Compute the overhead (FS structures)
+ */
+
+ /*
+ * All of the blocks before first_data_block are
+ * overhead
+ */
+ overhead = le32_to_cpu(sbi->s_es->s_first_data_block);
+
+ /*
+ * Add the overhead attributed to the superblock and
+ * block group descriptors. If the sparse superblocks
+ * feature is turned on, then not all groups have this.
+ */
+ for (i = 0; i < sbi->s_groups_count; i++)
+ overhead += ext2_bg_has_super(sb, i) +
+ ext2_bg_num_gdb(sb, i);
+
+ /*
+ * Every block group has an inode bitmap, a block
+ * bitmap, and an inode table.
+ */
+ overhead += (sbi->s_groups_count *
+ (2 + sbi->s_itb_per_group));
+ }
+
+ buf->f_type = EXT2_SUPER_MAGIC;
+ buf->f_bsize = sb->s_blocksize;
+ buf->f_blocks = le32_to_cpu(sbi->s_es->s_blocks_count) - overhead;
+ buf->f_bfree = ext2_count_free_blocks(sb);
+ buf->f_bavail = buf->f_bfree - le32_to_cpu(sbi->s_es->s_r_blocks_count);
+ if (buf->f_bfree < le32_to_cpu(sbi->s_es->s_r_blocks_count))
+ buf->f_bavail = 0;
+ buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);
+ buf->f_ffree = ext2_count_free_inodes (sb);
+ buf->f_namelen = EXT2_NAME_LEN;
+ return 0;
+}
+
+static struct super_block *ext2_get_sb(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *data)
+{
+ return get_sb_bdev(fs_type, flags, dev_name, data, ext2_fill_super);
+}
+
+#ifdef CONFIG_QUOTA
+
+/* Read data from quotafile - avoid pagecache and such because we cannot afford
+ * acquiring the locks... As quota files are never truncated and quota code
+ * itself serializes the operations (and noone else should touch the files)
+ * we don't have to be afraid of races */
+static ssize_t ext2_quota_read(struct super_block *sb, int type, char *data,
+ size_t len, loff_t off)
+{
+ struct inode *inode = sb_dqopt(sb)->files[type];
+ sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
+ int err = 0;
+ int offset = off & (sb->s_blocksize - 1);
+ int tocopy;
+ size_t toread;
+ struct buffer_head tmp_bh;
+ struct buffer_head *bh;
+ loff_t i_size = i_size_read(inode);
+
+ if (off > i_size)
+ return 0;
+ if (off+len > i_size)
+ len = i_size-off;
+ toread = len;
+ while (toread > 0) {
+ tocopy = sb->s_blocksize - offset < toread ?
+ sb->s_blocksize - offset : toread;
+
+ tmp_bh.b_state = 0;
+ err = ext2_get_block(inode, blk, &tmp_bh, 0);
+ if (err)
+ return err;
+ if (!buffer_mapped(&tmp_bh)) /* A hole? */
+ memset(data, 0, tocopy);
+ else {
+ bh = sb_bread(sb, tmp_bh.b_blocknr);
+ if (!bh)
+ return -EIO;
+ memcpy(data, bh->b_data+offset, tocopy);
+ brelse(bh);
+ }
+ offset = 0;
+ toread -= tocopy;
+ data += tocopy;
+ blk++;
+ }
+ return len;
+}
+
+/* Write to quotafile */
+static ssize_t ext2_quota_write(struct super_block *sb, int type,
+ const char *data, size_t len, loff_t off)
+{
+ struct inode *inode = sb_dqopt(sb)->files[type];
+ sector_t blk = off >> EXT2_BLOCK_SIZE_BITS(sb);
+ int err = 0;
+ int offset = off & (sb->s_blocksize - 1);
+ int tocopy;
+ size_t towrite = len;
+ struct buffer_head tmp_bh;
+ struct buffer_head *bh;
+
+ down(&inode->i_sem);
+ while (towrite > 0) {
+ tocopy = sb->s_blocksize - offset < towrite ?
+ sb->s_blocksize - offset : towrite;
+
+ tmp_bh.b_state = 0;
+ err = ext2_get_block(inode, blk, &tmp_bh, 1);
+ if (err)
+ goto out;
+ if (offset || tocopy != EXT2_BLOCK_SIZE(sb))
+ bh = sb_bread(sb, tmp_bh.b_blocknr);
+ else
+ bh = sb_getblk(sb, tmp_bh.b_blocknr);
+ if (!bh) {
+ err = -EIO;
+ goto out;
+ }
+ lock_buffer(bh);
+ memcpy(bh->b_data+offset, data, tocopy);
+ flush_dcache_page(bh->b_page);
+ set_buffer_uptodate(bh);
+ mark_buffer_dirty(bh);
+ unlock_buffer(bh);
+ brelse(bh);
+ offset = 0;
+ towrite -= tocopy;
+ data += tocopy;
+ blk++;
+ }
+out:
+ if (len == towrite)
+ return err;
+ if (inode->i_size < off+len-towrite)
+ i_size_write(inode, off+len-towrite);
+ inode->i_version++;
+ inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+ mark_inode_dirty(inode);
+ up(&inode->i_sem);
+ return len - towrite;
+}
+
+#endif
+
+static struct file_system_type ext2_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "ext2",
+ .get_sb = ext2_get_sb,
+ .kill_sb = kill_block_super,
+ .fs_flags = FS_REQUIRES_DEV,
+};
+
+static int __init init_ext2_fs(void)
+{
+ int err = init_ext2_xattr();
+ if (err)
+ return err;
+ err = init_inodecache();
+ if (err)
+ goto out1;
+ err = register_filesystem(&ext2_fs_type);
+ if (err)
+ goto out;
+ return 0;
+out:
+ destroy_inodecache();
+out1:
+ exit_ext2_xattr();
+ return err;
+}
+
+static void __exit exit_ext2_fs(void)
+{
+ unregister_filesystem(&ext2_fs_type);
+ destroy_inodecache();
+ exit_ext2_xattr();
+}
+
+module_init(init_ext2_fs)
+module_exit(exit_ext2_fs)
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