Initial import

1 files changed, 1580 insertions, 0 deletions

diff --git a/fs/ext2/super.c b/fs/ext2/super.c
new file mode 100644
index 000000000..d0e746e96
--- /dev/null
+++ b/fs/ext2/super.c
@@ -0,0 +1,1580 @@
+/*
+ *  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/module.h>
+#include <linux/string.h>
+#include <linux/fs.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/exportfs.h>
+#include <linux/vfs.h>
+#include <linux/seq_file.h>
+#include <linux/mount.h>
+#include <linux/log2.h>
+#include <linux/quotaops.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, int wait);
+static int ext2_remount (struct super_block * sb, int * flags, char * data);
+static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf);
+static int ext2_sync_fs(struct super_block *sb, int wait);
+static int ext2_freeze(struct super_block *sb);
+static int ext2_unfreeze(struct super_block *sb);
+
+void ext2_error(struct super_block *sb, const char *function,
+		const char *fmt, ...)
+{
+	struct va_format vaf;
+	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)) {
+		spin_lock(&sbi->s_lock);
+		sbi->s_mount_state |= EXT2_ERROR_FS;
+		es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
+		spin_unlock(&sbi->s_lock);
+		ext2_sync_super(sb, es, 1);
+	}
+
+	va_start(args, fmt);
+
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	printk(KERN_CRIT "EXT2-fs (%s): error: %s: %pV\n",
+	       sb->s_id, function, &vaf);
+
+	va_end(args);
+
+	if (test_opt(sb, ERRORS_PANIC))
+		panic("EXT2-fs: panic from previous error\n");
+	if (test_opt(sb, ERRORS_RO)) {
+		ext2_msg(sb, KERN_CRIT,
+			     "error: remounting filesystem read-only");
+		sb->s_flags |= MS_RDONLY;
+	}
+}
+
+void ext2_msg(struct super_block *sb, const char *prefix,
+		const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	va_start(args, fmt);
+
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	printk("%sEXT2-fs (%s): %pV\n", prefix, sb->s_id, &vaf);
+
+	va_end(args);
+}
+
+/*
+ * This must be called with sbi->s_lock held.
+ */
+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_msg(sb, KERN_WARNING,
+		     "warning: 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);
+
+	dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
+
+	ext2_xattr_put_super(sb);
+	if (!(sb->s_flags & MS_RDONLY)) {
+		struct ext2_super_block *es = sbi->s_es;
+
+		spin_lock(&sbi->s_lock);
+		es->s_state = cpu_to_le16(sbi->s_mount_state);
+		spin_unlock(&sbi->s_lock);
+		ext2_sync_super(sb, es, 1);
+	}
+	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->s_blockgroup_lock);
+	kfree(sbi);
+}
+
+static struct kmem_cache * ext2_inode_cachep;
+
+static struct inode *ext2_alloc_inode(struct super_block *sb)
+{
+	struct ext2_inode_info *ei;
+	ei = kmem_cache_alloc(ext2_inode_cachep, GFP_KERNEL);
+	if (!ei)
+		return NULL;
+	ei->i_block_alloc_info = NULL;
+	ei->vfs_inode.i_version = 1;
+#ifdef CONFIG_QUOTA
+	memset(&ei->i_dquot, 0, sizeof(ei->i_dquot));
+#endif
+
+	return &ei->vfs_inode;
+}
+
+static void ext2_i_callback(struct rcu_head *head)
+{
+	struct inode *inode = container_of(head, struct inode, i_rcu);
+	kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
+}
+
+static void ext2_destroy_inode(struct inode *inode)
+{
+	call_rcu(&inode->i_rcu, ext2_i_callback);
+}
+
+static void init_once(void *foo)
+{
+	struct ext2_inode_info *ei = (struct ext2_inode_info *) foo;
+
+	rwlock_init(&ei->i_meta_lock);
+#ifdef CONFIG_EXT2_FS_XATTR
+	init_rwsem(&ei->xattr_sem);
+#endif
+	mutex_init(&ei->truncate_mutex);
+	inode_init_once(&ei->vfs_inode);
+}
+
+static int __init init_inodecache(void)
+{
+	ext2_inode_cachep = kmem_cache_create("ext2_inode_cache",
+					     sizeof(struct ext2_inode_info),
+					     0, (SLAB_RECLAIM_ACCOUNT|
+						SLAB_MEM_SPREAD),
+					     init_once);
+	if (ext2_inode_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+static void destroy_inodecache(void)
+{
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(ext2_inode_cachep);
+}
+
+static int ext2_show_options(struct seq_file *seq, struct dentry *root)
+{
+	struct super_block *sb = root->d_sb;
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+	struct ext2_super_block *es = sbi->s_es;
+	unsigned long def_mount_opts;
+
+	spin_lock(&sbi->s_lock);
+	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
+
+	if (sbi->s_sb_block != 1)
+		seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
+	if (test_opt(sb, MINIX_DF))
+		seq_puts(seq, ",minixdf");
+	if (test_opt(sb, GRPID))
+		seq_puts(seq, ",grpid");
+	if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
+		seq_puts(seq, ",nogrpid");
+	if (!uid_eq(sbi->s_resuid, make_kuid(&init_user_ns, EXT2_DEF_RESUID)) ||
+	    le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
+		seq_printf(seq, ",resuid=%u",
+				from_kuid_munged(&init_user_ns, sbi->s_resuid));
+	}
+	if (!gid_eq(sbi->s_resgid, make_kgid(&init_user_ns, EXT2_DEF_RESGID)) ||
+	    le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
+		seq_printf(seq, ",resgid=%u",
+				from_kgid_munged(&init_user_ns, sbi->s_resgid));
+	}
+	if (test_opt(sb, ERRORS_RO)) {
+		int def_errors = le16_to_cpu(es->s_errors);
+
+		if (def_errors == EXT2_ERRORS_PANIC ||
+		    def_errors == EXT2_ERRORS_CONTINUE) {
+			seq_puts(seq, ",errors=remount-ro");
+		}
+	}
+	if (test_opt(sb, ERRORS_CONT))
+		seq_puts(seq, ",errors=continue");
+	if (test_opt(sb, ERRORS_PANIC))
+		seq_puts(seq, ",errors=panic");
+	if (test_opt(sb, NO_UID32))
+		seq_puts(seq, ",nouid32");
+	if (test_opt(sb, DEBUG))
+		seq_puts(seq, ",debug");
+	if (test_opt(sb, OLDALLOC))
+		seq_puts(seq, ",oldalloc");
+
+#ifdef CONFIG_EXT2_FS_XATTR
+	if (test_opt(sb, XATTR_USER))
+		seq_puts(seq, ",user_xattr");
+	if (!test_opt(sb, XATTR_USER) &&
+	    (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
+		seq_puts(seq, ",nouser_xattr");
+	}
+#endif
+
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+	if (test_opt(sb, POSIX_ACL))
+		seq_puts(seq, ",acl");
+	if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
+		seq_puts(seq, ",noacl");
+#endif
+
+	if (test_opt(sb, NOBH))
+		seq_puts(seq, ",nobh");
+
+#if defined(CONFIG_QUOTA)
+	if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
+		seq_puts(seq, ",usrquota");
+
+	if (sbi->s_mount_opt & EXT2_MOUNT_GRPQUOTA)
+		seq_puts(seq, ",grpquota");
+#endif
+
+#ifdef CONFIG_FS_DAX
+	if (sbi->s_mount_opt & EXT2_MOUNT_XIP)
+		seq_puts(seq, ",xip");
+	if (sbi->s_mount_opt & EXT2_MOUNT_DAX)
+		seq_puts(seq, ",dax");
+#endif
+
+	if (!test_opt(sb, RESERVATION))
+		seq_puts(seq, ",noreservation");
+
+	spin_unlock(&sbi->s_lock);
+	return 0;
+}
+
+#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);
+static struct dquot **ext2_get_dquots(struct inode *inode)
+{
+	return EXT2_I(inode)->i_dquot;
+}
+#endif
+
+static const struct super_operations ext2_sops = {
+	.alloc_inode	= ext2_alloc_inode,
+	.destroy_inode	= ext2_destroy_inode,
+	.write_inode	= ext2_write_inode,
+	.evict_inode	= ext2_evict_inode,
+	.put_super	= ext2_put_super,
+	.sync_fs	= ext2_sync_fs,
+	.freeze_fs	= ext2_freeze,
+	.unfreeze_fs	= ext2_unfreeze,
+	.statfs		= ext2_statfs,
+	.remount_fs	= ext2_remount,
+	.show_options	= ext2_show_options,
+#ifdef CONFIG_QUOTA
+	.quota_read	= ext2_quota_read,
+	.quota_write	= ext2_quota_write,
+	.get_dquots	= ext2_get_dquots,
+#endif
+};
+
+static struct inode *ext2_nfs_get_inode(struct super_block *sb,
+		u64 ino, u32 generation)
+{
+	struct inode *inode;
+
+	if (ino < EXT2_FIRST_INO(sb) && ino != EXT2_ROOT_INO)
+		return ERR_PTR(-ESTALE);
+	if (ino > le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count))
+		return ERR_PTR(-ESTALE);
+
+	/*
+	 * ext2_iget isn't quite right if the inode is currently unallocated!
+	 * However ext2_iget currently does appropriate checks to handle stale
+	 * inodes so everything is OK.
+	 */
+	inode = ext2_iget(sb, ino);
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
+	if (generation && inode->i_generation != generation) {
+		/* we didn't find the right inode.. */
+		iput(inode);
+		return ERR_PTR(-ESTALE);
+	}
+	return inode;
+}
+
+static struct dentry *ext2_fh_to_dentry(struct super_block *sb, struct fid *fid,
+		int fh_len, int fh_type)
+{
+	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
+				    ext2_nfs_get_inode);
+}
+
+static struct dentry *ext2_fh_to_parent(struct super_block *sb, struct fid *fid,
+		int fh_len, int fh_type)
+{
+	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
+				    ext2_nfs_get_inode);
+}
+
+static const struct export_operations ext2_export_ops = {
+	.fh_to_dentry = ext2_fh_to_dentry,
+	.fh_to_parent = ext2_fh_to_parent,
+	.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_nocheck, Opt_debug,
+	Opt_oldalloc, Opt_orlov, Opt_nobh, Opt_user_xattr, Opt_nouser_xattr,
+	Opt_acl, Opt_noacl, Opt_xip, Opt_dax, Opt_ignore, Opt_err, Opt_quota,
+	Opt_usrquota, Opt_grpquota, Opt_reservation, Opt_noreservation
+};
+
+static const 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_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_xip, "xip"},
+	{Opt_dax, "dax"},
+	{Opt_grpquota, "grpquota"},
+	{Opt_ignore, "noquota"},
+	{Opt_quota, "quota"},
+	{Opt_usrquota, "usrquota"},
+	{Opt_reservation, "reservation"},
+	{Opt_noreservation, "noreservation"},
+	{Opt_err, NULL}
+};
+
+static int parse_options(char *options, struct super_block *sb)
+{
+	char *p;
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+	substring_t args[MAX_OPT_ARGS];
+	int option;
+	kuid_t uid;
+	kgid_t gid;
+
+	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;
+			uid = make_kuid(current_user_ns(), option);
+			if (!uid_valid(uid)) {
+				ext2_msg(sb, KERN_ERR, "Invalid uid value %d", option);
+				return 0;
+
+			}
+			sbi->s_resuid = uid;
+			break;
+		case Opt_resgid:
+			if (match_int(&args[0], &option))
+				return 0;
+			gid = make_kgid(current_user_ns(), option);
+			if (!gid_valid(gid)) {
+				ext2_msg(sb, KERN_ERR, "Invalid gid value %d", option);
+				return 0;
+			}
+			sbi->s_resgid = gid;
+			break;
+		case Opt_sb:
+			/* handled by get_sb_block() instead of here */
+			/* *sb_block = match_int(&args[0]); */
+			break;
+		case Opt_err_panic:
+			clear_opt (sbi->s_mount_opt, ERRORS_CONT);
+			clear_opt (sbi->s_mount_opt, ERRORS_RO);
+			set_opt (sbi->s_mount_opt, ERRORS_PANIC);
+			break;
+		case Opt_err_ro:
+			clear_opt (sbi->s_mount_opt, ERRORS_CONT);
+			clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
+			set_opt (sbi->s_mount_opt, ERRORS_RO);
+			break;
+		case Opt_err_cont:
+			clear_opt (sbi->s_mount_opt, ERRORS_RO);
+			clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
+			set_opt (sbi->s_mount_opt, ERRORS_CONT);
+			break;
+		case Opt_nouid32:
+			set_opt (sbi->s_mount_opt, NO_UID32);
+			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:
+			ext2_msg(sb, KERN_INFO, "(no)user_xattr options"
+				"not supported");
+			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:
+			ext2_msg(sb, KERN_INFO,
+				"(no)acl options not supported");
+			break;
+#endif
+		case Opt_xip:
+			ext2_msg(sb, KERN_INFO, "use dax instead of xip");
+			set_opt(sbi->s_mount_opt, XIP);
+			/* Fall through */
+		case Opt_dax:
+#ifdef CONFIG_FS_DAX
+			set_opt(sbi->s_mount_opt, DAX);
+#else
+			ext2_msg(sb, KERN_INFO, "dax option not supported");
+#endif
+			break;
+
+#if defined(CONFIG_QUOTA)
+		case Opt_quota:
+		case Opt_usrquota:
+			set_opt(sbi->s_mount_opt, USRQUOTA);
+			break;
+
+		case Opt_grpquota:
+			set_opt(sbi->s_mount_opt, GRPQUOTA);
+			break;
+#else
+		case Opt_quota:
+		case Opt_usrquota:
+		case Opt_grpquota:
+			ext2_msg(sb, KERN_INFO,
+				"quota operations not supported");
+			break;
+#endif
+
+		case Opt_reservation:
+			set_opt(sbi->s_mount_opt, RESERVATION);
+			ext2_msg(sb, KERN_INFO, "reservations ON");
+			break;
+		case Opt_noreservation:
+			clear_opt(sbi->s_mount_opt, RESERVATION);
+			ext2_msg(sb, KERN_INFO, "reservations OFF");
+			break;
+		case Opt_ignore:
+			break;
+		default:
+			return 0;
+		}
+	}
+	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) {
+		ext2_msg(sb, KERN_ERR,
+			"error: revision level too high, "
+			"forcing read-only mode");
+		res = MS_RDONLY;
+	}
+	if (read_only)
+		return res;
+	if (!(sbi->s_mount_state & EXT2_VALID_FS))
+		ext2_msg(sb, KERN_WARNING,
+			"warning: mounting unchecked fs, "
+			"running e2fsck is recommended");
+	else if ((sbi->s_mount_state & EXT2_ERROR_FS))
+		ext2_msg(sb, KERN_WARNING,
+			"warning: mounting fs with errors, "
+			"running e2fsck is recommended");
+	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))
+		ext2_msg(sb, KERN_WARNING,
+			"warning: maximal mount count reached, "
+			"running e2fsck is recommended");
+	else if (le32_to_cpu(es->s_checkinterval) &&
+		(le32_to_cpu(es->s_lastcheck) +
+			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
+		ext2_msg(sb, KERN_WARNING,
+			"warning: checktime reached, "
+			"running e2fsck is recommended");
+	if (!le16_to_cpu(es->s_max_mnt_count))
+		es->s_max_mnt_count = cpu_to_le16(EXT2_DFL_MAX_MNT_COUNT);
+	le16_add_cpu(&es->s_mnt_count, 1);
+	if (test_opt (sb, DEBUG))
+		ext2_msg(sb, KERN_INFO, "%s, %s, bs=%lu, fs=%lu, gc=%lu, "
+			"bpg=%lu, ipg=%lu, mo=%04lx]",
+			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);
+	return res;
+}
+
+static int ext2_check_descriptors(struct super_block *sb)
+{
+	int i;
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+
+	ext2_debug ("Checking group descriptors");
+
+	for (i = 0; i < sbi->s_groups_count; i++) {
+		struct ext2_group_desc *gdp = ext2_get_group_desc(sb, i, NULL);
+		ext2_fsblk_t first_block = ext2_group_first_block_no(sb, i);
+		ext2_fsblk_t last_block;
+
+		if (i == sbi->s_groups_count - 1)
+			last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
+		else
+			last_block = first_block +
+				(EXT2_BLOCKS_PER_GROUP(sb) - 1);
+
+		if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
+		    le32_to_cpu(gdp->bg_block_bitmap) > last_block)
+		{
+			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) < first_block ||
+		    le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
+		{
+			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) < first_block ||
+		    le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group - 1 >
+		    last_block)
+		{
+			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;
+		}
+	}
+	return 1;
+}
+
+/*
+ * 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;
+	int meta_blocks;
+	loff_t upper_limit;
+
+	/* This is calculated to be the largest file size for a
+	 * dense, file such that the total number of
+	 * sectors in the file, including data and all indirect blocks,
+	 * does not exceed 2^32 -1
+	 * __u32 i_blocks representing the total number of
+	 * 512 bytes blocks of the file
+	 */
+	upper_limit = (1LL << 32) - 1;
+
+	/* total blocks in file system block size */
+	upper_limit >>= (bits - 9);
+
+
+	/* indirect blocks */
+	meta_blocks = 1;
+	/* double indirect blocks */
+	meta_blocks += 1 + (1LL << (bits-2));
+	/* tripple indirect blocks */
+	meta_blocks += 1 + (1LL << (bits-2)) + (1LL << (2*(bits-2)));
+
+	upper_limit -= meta_blocks;
+	upper_limit <<= bits;
+
+	res += 1LL << (bits-2);
+	res += 1LL << (2*(bits-2));
+	res += 1LL << (3*(bits-2));
+	res <<= bits;
+	if (res > upper_limit)
+		res = upper_limit;
+
+	if (res > MAX_LFS_FILESIZE)
+		res = MAX_LFS_FILESIZE;
+
+	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_meta_bg;
+	int has_super = 0;
+	
+	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 ext2_group_first_block_no(sb, bg) + has_super;
+}
+
+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;
+	long ret = -EINVAL;
+	int blocksize = BLOCK_SIZE;
+	int db_count;
+	int i, j;
+	__le32 features;
+	int err;
+
+	err = -ENOMEM;
+	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
+	if (!sbi)
+		goto failed;
+
+	sbi->s_blockgroup_lock =
+		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
+	if (!sbi->s_blockgroup_lock) {
+		kfree(sbi);
+		goto failed;
+	}
+	sb->s_fs_info = sbi;
+	sbi->s_sb_block = sb_block;
+
+	spin_lock_init(&sbi->s_lock);
+
+	/*
+	 * 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) {
+		ext2_msg(sb, KERN_ERR, "error: unable to set blocksize");
+		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))) {
+		ext2_msg(sb, KERN_ERR, "error: unable to read superblock");
+		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);
+#ifdef CONFIG_EXT2_FS_XATTR
+	if (def_mount_opts & EXT2_DEFM_XATTR_USER)
+		set_opt(sbi->s_mount_opt, XATTR_USER);
+#endif
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+	if (def_mount_opts & EXT2_DEFM_ACL)
+		set_opt(sbi->s_mount_opt, POSIX_ACL);
+#endif
+	
+	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_CONTINUE)
+		set_opt(sbi->s_mount_opt, ERRORS_CONT);
+	else
+		set_opt(sbi->s_mount_opt, ERRORS_RO);
+
+	sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid));
+	sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid));
+	
+	set_opt(sbi->s_mount_opt, RESERVATION);
+
+	if (!parse_options((char *) data, sb))
+		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)))
+		ext2_msg(sb, KERN_WARNING,
+			"warning: feature flags set on rev 0 fs, "
+			"running e2fsck is recommended");
+	/*
+	 * 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) {
+		ext2_msg(sb, KERN_ERR,	"error: couldn't mount because of "
+		       "unsupported optional features (%x)",
+			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))){
+		ext2_msg(sb, KERN_ERR, "error: couldn't mount RDWR because of "
+		       "unsupported optional features (%x)",
+		       le32_to_cpu(features));
+		goto failed_mount;
+	}
+
+	blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
+
+	if (sbi->s_mount_opt & EXT2_MOUNT_DAX) {
+		if (blocksize != PAGE_SIZE) {
+			ext2_msg(sb, KERN_ERR,
+					"error: unsupported blocksize for dax");
+			goto failed_mount;
+		}
+		if (!sb->s_bdev->bd_disk->fops->direct_access) {
+			ext2_msg(sb, KERN_ERR,
+					"error: device does not support dax");
+			goto failed_mount;
+		}
+	}
+
+	/* If the blocksize doesn't match, re-read the thing.. */
+	if (sb->s_blocksize != blocksize) {
+		brelse(bh);
+
+		if (!sb_set_blocksize(sb, blocksize)) {
+			ext2_msg(sb, KERN_ERR,
+				"error: bad blocksize %d", blocksize);
+			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) {
+			ext2_msg(sb, KERN_ERR, "error: couldn't read"
+				"superblock on 2nd try");
+			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)) {
+			ext2_msg(sb, KERN_ERR, "error: magic mismatch");
+			goto failed_mount;
+		}
+	}
+
+	sb->s_maxbytes = ext2_max_size(sb->s_blocksize_bits);
+	sb->s_max_links = EXT2_LINK_MAX;
+
+	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) ||
+		    !is_power_of_2(sbi->s_inode_size) ||
+		    (sbi->s_inode_size > blocksize)) {
+			ext2_msg(sb, KERN_ERR,
+				"error: unsupported inode size: %d",
+				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 || sbi->s_inodes_per_group == 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 =
+		ilog2 (EXT2_ADDR_PER_BLOCK(sb));
+	sbi->s_desc_per_block_bits =
+		ilog2 (EXT2_DESC_PER_BLOCK(sb));
+
+	if (sb->s_magic != EXT2_SUPER_MAGIC)
+		goto cantfind_ext2;
+
+	if (sb->s_blocksize != bh->b_size) {
+		if (!silent)
+			ext2_msg(sb, KERN_ERR, "error: unsupported blocksize");
+		goto failed_mount;
+	}
+
+	if (sb->s_blocksize != sbi->s_frag_size) {
+		ext2_msg(sb, KERN_ERR,
+			"error: fragsize %lu != blocksize %lu"
+			"(not supported yet)",
+			sbi->s_frag_size, sb->s_blocksize);
+		goto failed_mount;
+	}
+
+	if (sbi->s_blocks_per_group > sb->s_blocksize * 8) {
+		ext2_msg(sb, KERN_ERR,
+			"error: #blocks per group too big: %lu",
+			sbi->s_blocks_per_group);
+		goto failed_mount;
+	}
+	if (sbi->s_frags_per_group > sb->s_blocksize * 8) {
+		ext2_msg(sb, KERN_ERR,
+			"error: #fragments per group too big: %lu",
+			sbi->s_frags_per_group);
+		goto failed_mount;
+	}
+	if (sbi->s_inodes_per_group > sb->s_blocksize * 8) {
+		ext2_msg(sb, KERN_ERR,
+			"error: #inodes per group too big: %lu",
+			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) - 1)
+ 					/ EXT2_BLOCKS_PER_GROUP(sb)) + 1;
+	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) {
+		ext2_msg(sb, KERN_ERR, "error: not enough memory");
+		goto failed_mount;
+	}
+	bgl_lock_init(sbi->s_blockgroup_lock);
+	sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL);
+	if (!sbi->s_debts) {
+		ext2_msg(sb, KERN_ERR, "error: not enough memory");
+		goto failed_mount_group_desc;
+	}
+	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]);
+			ext2_msg(sb, KERN_ERR,
+				"error: unable to read group descriptors");
+			goto failed_mount_group_desc;
+		}
+	}
+	if (!ext2_check_descriptors (sb)) {
+		ext2_msg(sb, KERN_ERR, "group descriptors corrupted");
+		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);
+
+	/* per fileystem reservation list head & lock */
+	spin_lock_init(&sbi->s_rsv_window_lock);
+	sbi->s_rsv_window_root = RB_ROOT;
+	/*
+	 * Add a single, static dummy reservation to the start of the
+	 * reservation window list --- it gives us a placeholder for
+	 * append-at-start-of-list which makes the allocation logic
+	 * _much_ simpler.
+	 */
+	sbi->s_rsv_window_head.rsv_start = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
+	sbi->s_rsv_window_head.rsv_end = EXT2_RESERVE_WINDOW_NOT_ALLOCATED;
+	sbi->s_rsv_window_head.rsv_alloc_hit = 0;
+	sbi->s_rsv_window_head.rsv_goal_size = 0;
+	ext2_rsv_window_add(sb, &sbi->s_rsv_window_head);
+
+	err = percpu_counter_init(&sbi->s_freeblocks_counter,
+				ext2_count_free_blocks(sb), GFP_KERNEL);
+	if (!err) {
+		err = percpu_counter_init(&sbi->s_freeinodes_counter,
+				ext2_count_free_inodes(sb), GFP_KERNEL);
+	}
+	if (!err) {
+		err = percpu_counter_init(&sbi->s_dirs_counter,
+				ext2_count_dirs(sb), GFP_KERNEL);
+	}
+	if (err) {
+		ext2_msg(sb, KERN_ERR, "error: insufficient memory");
+		goto failed_mount3;
+	}
+	/*
+	 * 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;
+
+#ifdef CONFIG_QUOTA
+	sb->dq_op = &dquot_operations;
+	sb->s_qcop = &dquot_quotactl_ops;
+	sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP;
+#endif
+
+	root = ext2_iget(sb, EXT2_ROOT_INO);
+	if (IS_ERR(root)) {
+		ret = PTR_ERR(root);
+		goto failed_mount3;
+	}
+	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
+		iput(root);
+		ext2_msg(sb, KERN_ERR, "error: corrupt root inode, run e2fsck");
+		goto failed_mount3;
+	}
+
+	sb->s_root = d_make_root(root);
+	if (!sb->s_root) {
+		ext2_msg(sb, KERN_ERR, "error: get root inode failed");
+		ret = -ENOMEM;
+		goto failed_mount3;
+	}
+	if (EXT2_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL))
+		ext2_msg(sb, KERN_WARNING,
+			"warning: mounting ext3 filesystem as ext2");
+	if (ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY))
+		sb->s_flags |= MS_RDONLY;
+	ext2_write_super(sb);
+	return 0;
+
+cantfind_ext2:
+	if (!silent)
+		ext2_msg(sb, KERN_ERR,
+			"error: can't find an ext2 filesystem on dev %s.",
+			sb->s_id);
+	goto failed_mount;
+failed_mount3:
+	percpu_counter_destroy(&sbi->s_freeblocks_counter);
+	percpu_counter_destroy(&sbi->s_freeinodes_counter);
+	percpu_counter_destroy(&sbi->s_dirs_counter);
+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->s_blockgroup_lock);
+	kfree(sbi);
+failed:
+	return ret;
+}
+
+static void ext2_clear_super_error(struct super_block *sb)
+{
+	struct buffer_head *sbh = EXT2_SB(sb)->s_sbh;
+
+	if (buffer_write_io_error(sbh)) {
+		/*
+		 * Oh, dear.  A previous attempt to write the
+		 * superblock failed.  This could happen because the
+		 * USB device was yanked out.  Or it could happen to
+		 * be a transient write error and maybe the block will
+		 * be remapped.  Nothing we can do but to retry the
+		 * write and hope for the best.
+		 */
+		ext2_msg(sb, KERN_ERR,
+		       "previous I/O error to superblock detected\n");
+		clear_buffer_write_io_error(sbh);
+		set_buffer_uptodate(sbh);
+	}
+}
+
+static void ext2_sync_super(struct super_block *sb, struct ext2_super_block *es,
+			    int wait)
+{
+	ext2_clear_super_error(sb);
+	spin_lock(&EXT2_SB(sb)->s_lock);
+	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());
+	/* unlock before we do IO */
+	spin_unlock(&EXT2_SB(sb)->s_lock);
+	mark_buffer_dirty(EXT2_SB(sb)->s_sbh);
+	if (wait)
+		sync_dirty_buffer(EXT2_SB(sb)->s_sbh);
+}
+
+/*
+ * 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.
+ */
+static int ext2_sync_fs(struct super_block *sb, int wait)
+{
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+	struct ext2_super_block *es = EXT2_SB(sb)->s_es;
+
+	/*
+	 * Write quota structures to quota file, sync_blockdev() will write
+	 * them to disk later
+	 */
+	dquot_writeback_dquots(sb, -1);
+
+	spin_lock(&sbi->s_lock);
+	if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
+		ext2_debug("setting valid to 0\n");
+		es->s_state &= cpu_to_le16(~EXT2_VALID_FS);
+	}
+	spin_unlock(&sbi->s_lock);
+	ext2_sync_super(sb, es, wait);
+	return 0;
+}
+
+static int ext2_freeze(struct super_block *sb)
+{
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+
+	/*
+	 * Open but unlinked files present? Keep EXT2_VALID_FS flag cleared
+	 * because we have unattached inodes and thus filesystem is not fully
+	 * consistent.
+	 */
+	if (atomic_long_read(&sb->s_remove_count)) {
+		ext2_sync_fs(sb, 1);
+		return 0;
+	}
+	/* Set EXT2_FS_VALID flag */
+	spin_lock(&sbi->s_lock);
+	sbi->s_es->s_state = cpu_to_le16(sbi->s_mount_state);
+	spin_unlock(&sbi->s_lock);
+	ext2_sync_super(sb, sbi->s_es, 1);
+
+	return 0;
+}
+
+static int ext2_unfreeze(struct super_block *sb)
+{
+	/* Just write sb to clear EXT2_VALID_FS flag */
+	ext2_write_super(sb);
+
+	return 0;
+}
+
+void ext2_write_super(struct super_block *sb)
+{
+	if (!(sb->s_flags & MS_RDONLY))
+		ext2_sync_fs(sb, 1);
+}
+
+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;
+	struct ext2_mount_options old_opts;
+	unsigned long old_sb_flags;
+	int err;
+
+	sync_filesystem(sb);
+	spin_lock(&sbi->s_lock);
+
+	/* Store the old options */
+	old_sb_flags = sb->s_flags;
+	old_opts.s_mount_opt = sbi->s_mount_opt;
+	old_opts.s_resuid = sbi->s_resuid;
+	old_opts.s_resgid = sbi->s_resgid;
+
+	/*
+	 * Allow the "check" option to be passed as a remount option.
+	 */
+	if (!parse_options(data, sb)) {
+		err = -EINVAL;
+		goto restore_opts;
+	}
+
+	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
+		((sbi->s_mount_opt & EXT2_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
+
+	es = sbi->s_es;
+	if ((sbi->s_mount_opt ^ old_opts.s_mount_opt) & EXT2_MOUNT_DAX) {
+		ext2_msg(sb, KERN_WARNING, "warning: refusing change of "
+			 "dax flag with busy inodes while remounting");
+		sbi->s_mount_opt ^= EXT2_MOUNT_DAX;
+	}
+	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
+		spin_unlock(&sbi->s_lock);
+		return 0;
+	}
+	if (*flags & MS_RDONLY) {
+		if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
+		    !(sbi->s_mount_state & EXT2_VALID_FS)) {
+			spin_unlock(&sbi->s_lock);
+			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());
+		spin_unlock(&sbi->s_lock);
+
+		err = dquot_suspend(sb, -1);
+		if (err < 0) {
+			spin_lock(&sbi->s_lock);
+			goto restore_opts;
+		}
+
+		ext2_sync_super(sb, es, 1);
+	} else {
+		__le32 ret = EXT2_HAS_RO_COMPAT_FEATURE(sb,
+					       ~EXT2_FEATURE_RO_COMPAT_SUPP);
+		if (ret) {
+			ext2_msg(sb, KERN_WARNING,
+				"warning: couldn't remount RDWR because of "
+				"unsupported optional features (%x).",
+				le32_to_cpu(ret));
+			err = -EROFS;
+			goto restore_opts;
+		}
+		/*
+		 * 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;
+		spin_unlock(&sbi->s_lock);
+
+		ext2_write_super(sb);
+
+		dquot_resume(sb, -1);
+	}
+
+	return 0;
+restore_opts:
+	sbi->s_mount_opt = old_opts.s_mount_opt;
+	sbi->s_resuid = old_opts.s_resuid;
+	sbi->s_resgid = old_opts.s_resgid;
+	sb->s_flags = old_sb_flags;
+	spin_unlock(&sbi->s_lock);
+	return err;
+}
+
+static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf)
+{
+	struct super_block *sb = dentry->d_sb;
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+	struct ext2_super_block *es = sbi->s_es;
+	u64 fsid;
+
+	spin_lock(&sbi->s_lock);
+
+	if (test_opt (sb, MINIX_DF))
+		sbi->s_overhead_last = 0;
+	else if (sbi->s_blocks_last != le32_to_cpu(es->s_blocks_count)) {
+		unsigned long i, overhead = 0;
+		smp_rmb();
+
+		/*
+		 * Compute the overhead (FS structures). This is constant
+		 * for a given filesystem unless the number of block groups
+		 * changes so we cache the previous value until it does.
+		 */
+
+		/*
+		 * All of the blocks before first_data_block are
+		 * overhead
+		 */
+		overhead = le32_to_cpu(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));
+		sbi->s_overhead_last = overhead;
+		smp_wmb();
+		sbi->s_blocks_last = le32_to_cpu(es->s_blocks_count);
+	}
+
+	buf->f_type = EXT2_SUPER_MAGIC;
+	buf->f_bsize = sb->s_blocksize;
+	buf->f_blocks = le32_to_cpu(es->s_blocks_count) - sbi->s_overhead_last;
+	buf->f_bfree = ext2_count_free_blocks(sb);
+	es->s_free_blocks_count = cpu_to_le32(buf->f_bfree);
+	buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
+	if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
+		buf->f_bavail = 0;
+	buf->f_files = le32_to_cpu(es->s_inodes_count);
+	buf->f_ffree = ext2_count_free_inodes(sb);
+	es->s_free_inodes_count = cpu_to_le32(buf->f_ffree);
+	buf->f_namelen = EXT2_NAME_LEN;
+	fsid = le64_to_cpup((void *)es->s_uuid) ^
+	       le64_to_cpup((void *)es->s_uuid + sizeof(u64));
+	buf->f_fsid.val[0] = fsid & 0xFFFFFFFFUL;
+	buf->f_fsid.val[1] = (fsid >> 32) & 0xFFFFFFFFUL;
+	spin_unlock(&sbi->s_lock);
+	return 0;
+}
+
+static struct dentry *ext2_mount(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *data)
+{
+	return mount_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 no one 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;
+		tmp_bh.b_size = sb->s_blocksize;
+		err = ext2_get_block(inode, blk, &tmp_bh, 0);
+		if (err < 0)
+			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;
+
+	while (towrite > 0) {
+		tocopy = sb->s_blocksize - offset < towrite ?
+				sb->s_blocksize - offset : towrite;
+
+		tmp_bh.b_state = 0;
+		tmp_bh.b_size = sb->s_blocksize;
+		err = ext2_get_block(inode, blk, &tmp_bh, 1);
+		if (err < 0)
+			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 (unlikely(!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);
+	return len - towrite;
+}
+
+#endif
+
+static struct file_system_type ext2_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "ext2",
+	.mount		= ext2_mount,
+	.kill_sb	= kill_block_super,
+	.fs_flags	= FS_REQUIRES_DEV,
+};
+MODULE_ALIAS_FS("ext2");
+
+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_AUTHOR("Remy Card and others");
+MODULE_DESCRIPTION("Second Extended Filesystem");
+MODULE_LICENSE("GPL");
+module_init(init_ext2_fs)
+module_exit(exit_ext2_fs)