Initial import

1 files changed, 2220 insertions, 0 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
new file mode 100644
index 000000000..9e66f5e72
--- /dev/null
+++ b/fs/btrfs/super.c
@@ -0,0 +1,2220 @@
+/*
+ * Copyright (C) 2007 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/blkdev.h>
+#include <linux/module.h>
+#include <linux/buffer_head.h>
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+#include <linux/time.h>
+#include <linux/init.h>
+#include <linux/seq_file.h>
+#include <linux/string.h>
+#include <linux/backing-dev.h>
+#include <linux/mount.h>
+#include <linux/mpage.h>
+#include <linux/swap.h>
+#include <linux/writeback.h>
+#include <linux/statfs.h>
+#include <linux/compat.h>
+#include <linux/parser.h>
+#include <linux/ctype.h>
+#include <linux/namei.h>
+#include <linux/miscdevice.h>
+#include <linux/magic.h>
+#include <linux/slab.h>
+#include <linux/cleancache.h>
+#include <linux/ratelimit.h>
+#include <linux/btrfs.h>
+#include "delayed-inode.h"
+#include "ctree.h"
+#include "disk-io.h"
+#include "transaction.h"
+#include "btrfs_inode.h"
+#include "print-tree.h"
+#include "hash.h"
+#include "props.h"
+#include "xattr.h"
+#include "volumes.h"
+#include "export.h"
+#include "compression.h"
+#include "rcu-string.h"
+#include "dev-replace.h"
+#include "free-space-cache.h"
+#include "backref.h"
+#include "tests/btrfs-tests.h"
+
+#include "qgroup.h"
+#define CREATE_TRACE_POINTS
+#include <trace/events/btrfs.h>
+
+static const struct super_operations btrfs_super_ops;
+static struct file_system_type btrfs_fs_type;
+
+static int btrfs_remount(struct super_block *sb, int *flags, char *data);
+
+static const char *btrfs_decode_error(int errno)
+{
+	char *errstr = "unknown";
+
+	switch (errno) {
+	case -EIO:
+		errstr = "IO failure";
+		break;
+	case -ENOMEM:
+		errstr = "Out of memory";
+		break;
+	case -EROFS:
+		errstr = "Readonly filesystem";
+		break;
+	case -EEXIST:
+		errstr = "Object already exists";
+		break;
+	case -ENOSPC:
+		errstr = "No space left";
+		break;
+	case -ENOENT:
+		errstr = "No such entry";
+		break;
+	}
+
+	return errstr;
+}
+
+static void save_error_info(struct btrfs_fs_info *fs_info)
+{
+	/*
+	 * today we only save the error info into ram.  Long term we'll
+	 * also send it down to the disk
+	 */
+	set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
+}
+
+/* btrfs handle error by forcing the filesystem readonly */
+static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
+{
+	struct super_block *sb = fs_info->sb;
+
+	if (sb->s_flags & MS_RDONLY)
+		return;
+
+	if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
+		sb->s_flags |= MS_RDONLY;
+		btrfs_info(fs_info, "forced readonly");
+		/*
+		 * Note that a running device replace operation is not
+		 * canceled here although there is no way to update
+		 * the progress. It would add the risk of a deadlock,
+		 * therefore the canceling is ommited. The only penalty
+		 * is that some I/O remains active until the procedure
+		 * completes. The next time when the filesystem is
+		 * mounted writeable again, the device replace
+		 * operation continues.
+		 */
+	}
+}
+
+#ifdef CONFIG_PRINTK
+/*
+ * __btrfs_std_error decodes expected errors from the caller and
+ * invokes the approciate error response.
+ */
+void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
+		       unsigned int line, int errno, const char *fmt, ...)
+{
+	struct super_block *sb = fs_info->sb;
+	const char *errstr;
+
+	/*
+	 * Special case: if the error is EROFS, and we're already
+	 * under MS_RDONLY, then it is safe here.
+	 */
+	if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
+  		return;
+
+	errstr = btrfs_decode_error(errno);
+	if (fmt) {
+		struct va_format vaf;
+		va_list args;
+
+		va_start(args, fmt);
+		vaf.fmt = fmt;
+		vaf.va = &args;
+
+		printk(KERN_CRIT
+			"BTRFS: error (device %s) in %s:%d: errno=%d %s (%pV)\n",
+			sb->s_id, function, line, errno, errstr, &vaf);
+		va_end(args);
+	} else {
+		printk(KERN_CRIT "BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
+			sb->s_id, function, line, errno, errstr);
+	}
+
+	/* Don't go through full error handling during mount */
+	save_error_info(fs_info);
+	if (sb->s_flags & MS_BORN)
+		btrfs_handle_error(fs_info);
+}
+
+static const char * const logtypes[] = {
+	"emergency",
+	"alert",
+	"critical",
+	"error",
+	"warning",
+	"notice",
+	"info",
+	"debug",
+};
+
+void btrfs_printk(const struct btrfs_fs_info *fs_info, const char *fmt, ...)
+{
+	struct super_block *sb = fs_info->sb;
+	char lvl[4];
+	struct va_format vaf;
+	va_list args;
+	const char *type = logtypes[4];
+	int kern_level;
+
+	va_start(args, fmt);
+
+	kern_level = printk_get_level(fmt);
+	if (kern_level) {
+		size_t size = printk_skip_level(fmt) - fmt;
+		memcpy(lvl, fmt,  size);
+		lvl[size] = '\0';
+		fmt += size;
+		type = logtypes[kern_level - '0'];
+	} else
+		*lvl = '\0';
+
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	printk("%sBTRFS %s (device %s): %pV\n", lvl, type, sb->s_id, &vaf);
+
+	va_end(args);
+}
+
+#else
+
+void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
+		       unsigned int line, int errno, const char *fmt, ...)
+{
+	struct super_block *sb = fs_info->sb;
+
+	/*
+	 * Special case: if the error is EROFS, and we're already
+	 * under MS_RDONLY, then it is safe here.
+	 */
+	if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
+		return;
+
+	/* Don't go through full error handling during mount */
+	if (sb->s_flags & MS_BORN) {
+		save_error_info(fs_info);
+		btrfs_handle_error(fs_info);
+	}
+}
+#endif
+
+/*
+ * We only mark the transaction aborted and then set the file system read-only.
+ * This will prevent new transactions from starting or trying to join this
+ * one.
+ *
+ * This means that error recovery at the call site is limited to freeing
+ * any local memory allocations and passing the error code up without
+ * further cleanup. The transaction should complete as it normally would
+ * in the call path but will return -EIO.
+ *
+ * We'll complete the cleanup in btrfs_end_transaction and
+ * btrfs_commit_transaction.
+ */
+void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
+			       struct btrfs_root *root, const char *function,
+			       unsigned int line, int errno)
+{
+	/*
+	 * Report first abort since mount
+	 */
+	if (!test_and_set_bit(BTRFS_FS_STATE_TRANS_ABORTED,
+				&root->fs_info->fs_state)) {
+		WARN(1, KERN_DEBUG "BTRFS: Transaction aborted (error %d)\n",
+				errno);
+	}
+	trans->aborted = errno;
+	/* Nothing used. The other threads that have joined this
+	 * transaction may be able to continue. */
+	if (!trans->blocks_used && list_empty(&trans->new_bgs)) {
+		const char *errstr;
+
+		errstr = btrfs_decode_error(errno);
+		btrfs_warn(root->fs_info,
+		           "%s:%d: Aborting unused transaction(%s).",
+		           function, line, errstr);
+		return;
+	}
+	ACCESS_ONCE(trans->transaction->aborted) = errno;
+	/* Wake up anybody who may be waiting on this transaction */
+	wake_up(&root->fs_info->transaction_wait);
+	wake_up(&root->fs_info->transaction_blocked_wait);
+	__btrfs_std_error(root->fs_info, function, line, errno, NULL);
+}
+/*
+ * __btrfs_panic decodes unexpected, fatal errors from the caller,
+ * issues an alert, and either panics or BUGs, depending on mount options.
+ */
+void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
+		   unsigned int line, int errno, const char *fmt, ...)
+{
+	char *s_id = "<unknown>";
+	const char *errstr;
+	struct va_format vaf = { .fmt = fmt };
+	va_list args;
+
+	if (fs_info)
+		s_id = fs_info->sb->s_id;
+
+	va_start(args, fmt);
+	vaf.va = &args;
+
+	errstr = btrfs_decode_error(errno);
+	if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
+		panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
+			s_id, function, line, &vaf, errno, errstr);
+
+	btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
+		   function, line, &vaf, errno, errstr);
+	va_end(args);
+	/* Caller calls BUG() */
+}
+
+static void btrfs_put_super(struct super_block *sb)
+{
+	close_ctree(btrfs_sb(sb)->tree_root);
+}
+
+enum {
+	Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
+	Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
+	Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
+	Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
+	Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
+	Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
+	Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache,
+	Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
+	Opt_check_integrity, Opt_check_integrity_including_extent_data,
+	Opt_check_integrity_print_mask, Opt_fatal_errors, Opt_rescan_uuid_tree,
+	Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
+	Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
+	Opt_datasum, Opt_treelog, Opt_noinode_cache,
+	Opt_err,
+};
+
+static match_table_t tokens = {
+	{Opt_degraded, "degraded"},
+	{Opt_subvol, "subvol=%s"},
+	{Opt_subvolid, "subvolid=%s"},
+	{Opt_device, "device=%s"},
+	{Opt_nodatasum, "nodatasum"},
+	{Opt_datasum, "datasum"},
+	{Opt_nodatacow, "nodatacow"},
+	{Opt_datacow, "datacow"},
+	{Opt_nobarrier, "nobarrier"},
+	{Opt_barrier, "barrier"},
+	{Opt_max_inline, "max_inline=%s"},
+	{Opt_alloc_start, "alloc_start=%s"},
+	{Opt_thread_pool, "thread_pool=%d"},
+	{Opt_compress, "compress"},
+	{Opt_compress_type, "compress=%s"},
+	{Opt_compress_force, "compress-force"},
+	{Opt_compress_force_type, "compress-force=%s"},
+	{Opt_ssd, "ssd"},
+	{Opt_ssd_spread, "ssd_spread"},
+	{Opt_nossd, "nossd"},
+	{Opt_acl, "acl"},
+	{Opt_noacl, "noacl"},
+	{Opt_notreelog, "notreelog"},
+	{Opt_treelog, "treelog"},
+	{Opt_flushoncommit, "flushoncommit"},
+	{Opt_noflushoncommit, "noflushoncommit"},
+	{Opt_ratio, "metadata_ratio=%d"},
+	{Opt_discard, "discard"},
+	{Opt_nodiscard, "nodiscard"},
+	{Opt_space_cache, "space_cache"},
+	{Opt_clear_cache, "clear_cache"},
+	{Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
+	{Opt_enospc_debug, "enospc_debug"},
+	{Opt_noenospc_debug, "noenospc_debug"},
+	{Opt_subvolrootid, "subvolrootid=%d"},
+	{Opt_defrag, "autodefrag"},
+	{Opt_nodefrag, "noautodefrag"},
+	{Opt_inode_cache, "inode_cache"},
+	{Opt_noinode_cache, "noinode_cache"},
+	{Opt_no_space_cache, "nospace_cache"},
+	{Opt_recovery, "recovery"},
+	{Opt_skip_balance, "skip_balance"},
+	{Opt_check_integrity, "check_int"},
+	{Opt_check_integrity_including_extent_data, "check_int_data"},
+	{Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
+	{Opt_rescan_uuid_tree, "rescan_uuid_tree"},
+	{Opt_fatal_errors, "fatal_errors=%s"},
+	{Opt_commit_interval, "commit=%d"},
+	{Opt_err, NULL},
+};
+
+/*
+ * Regular mount options parser.  Everything that is needed only when
+ * reading in a new superblock is parsed here.
+ * XXX JDM: This needs to be cleaned up for remount.
+ */
+int btrfs_parse_options(struct btrfs_root *root, char *options)
+{
+	struct btrfs_fs_info *info = root->fs_info;
+	substring_t args[MAX_OPT_ARGS];
+	char *p, *num, *orig = NULL;
+	u64 cache_gen;
+	int intarg;
+	int ret = 0;
+	char *compress_type;
+	bool compress_force = false;
+
+	cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
+	if (cache_gen)
+		btrfs_set_opt(info->mount_opt, SPACE_CACHE);
+
+	if (!options)
+		goto out;
+
+	/*
+	 * strsep changes the string, duplicate it because parse_options
+	 * gets called twice
+	 */
+	options = kstrdup(options, GFP_NOFS);
+	if (!options)
+		return -ENOMEM;
+
+	orig = options;
+
+	while ((p = strsep(&options, ",")) != NULL) {
+		int token;
+		if (!*p)
+			continue;
+
+		token = match_token(p, tokens, args);
+		switch (token) {
+		case Opt_degraded:
+			btrfs_info(root->fs_info, "allowing degraded mounts");
+			btrfs_set_opt(info->mount_opt, DEGRADED);
+			break;
+		case Opt_subvol:
+		case Opt_subvolid:
+		case Opt_subvolrootid:
+		case Opt_device:
+			/*
+			 * These are parsed by btrfs_parse_early_options
+			 * and can be happily ignored here.
+			 */
+			break;
+		case Opt_nodatasum:
+			btrfs_set_and_info(root, NODATASUM,
+					   "setting nodatasum");
+			break;
+		case Opt_datasum:
+			if (btrfs_test_opt(root, NODATASUM)) {
+				if (btrfs_test_opt(root, NODATACOW))
+					btrfs_info(root->fs_info, "setting datasum, datacow enabled");
+				else
+					btrfs_info(root->fs_info, "setting datasum");
+			}
+			btrfs_clear_opt(info->mount_opt, NODATACOW);
+			btrfs_clear_opt(info->mount_opt, NODATASUM);
+			break;
+		case Opt_nodatacow:
+			if (!btrfs_test_opt(root, NODATACOW)) {
+				if (!btrfs_test_opt(root, COMPRESS) ||
+				    !btrfs_test_opt(root, FORCE_COMPRESS)) {
+					btrfs_info(root->fs_info,
+						   "setting nodatacow, compression disabled");
+				} else {
+					btrfs_info(root->fs_info, "setting nodatacow");
+				}
+			}
+			btrfs_clear_opt(info->mount_opt, COMPRESS);
+			btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
+			btrfs_set_opt(info->mount_opt, NODATACOW);
+			btrfs_set_opt(info->mount_opt, NODATASUM);
+			break;
+		case Opt_datacow:
+			btrfs_clear_and_info(root, NODATACOW,
+					     "setting datacow");
+			break;
+		case Opt_compress_force:
+		case Opt_compress_force_type:
+			compress_force = true;
+			/* Fallthrough */
+		case Opt_compress:
+		case Opt_compress_type:
+			if (token == Opt_compress ||
+			    token == Opt_compress_force ||
+			    strcmp(args[0].from, "zlib") == 0) {
+				compress_type = "zlib";
+				info->compress_type = BTRFS_COMPRESS_ZLIB;
+				btrfs_set_opt(info->mount_opt, COMPRESS);
+				btrfs_clear_opt(info->mount_opt, NODATACOW);
+				btrfs_clear_opt(info->mount_opt, NODATASUM);
+			} else if (strcmp(args[0].from, "lzo") == 0) {
+				compress_type = "lzo";
+				info->compress_type = BTRFS_COMPRESS_LZO;
+				btrfs_set_opt(info->mount_opt, COMPRESS);
+				btrfs_clear_opt(info->mount_opt, NODATACOW);
+				btrfs_clear_opt(info->mount_opt, NODATASUM);
+				btrfs_set_fs_incompat(info, COMPRESS_LZO);
+			} else if (strncmp(args[0].from, "no", 2) == 0) {
+				compress_type = "no";
+				btrfs_clear_opt(info->mount_opt, COMPRESS);
+				btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
+				compress_force = false;
+			} else {
+				ret = -EINVAL;
+				goto out;
+			}
+
+			if (compress_force) {
+				btrfs_set_and_info(root, FORCE_COMPRESS,
+						   "force %s compression",
+						   compress_type);
+			} else {
+				if (!btrfs_test_opt(root, COMPRESS))
+					btrfs_info(root->fs_info,
+						   "btrfs: use %s compression",
+						   compress_type);
+				/*
+				 * If we remount from compress-force=xxx to
+				 * compress=xxx, we need clear FORCE_COMPRESS
+				 * flag, otherwise, there is no way for users
+				 * to disable forcible compression separately.
+				 */
+				btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
+			}
+			break;
+		case Opt_ssd:
+			btrfs_set_and_info(root, SSD,
+					   "use ssd allocation scheme");
+			break;
+		case Opt_ssd_spread:
+			btrfs_set_and_info(root, SSD_SPREAD,
+					   "use spread ssd allocation scheme");
+			btrfs_set_opt(info->mount_opt, SSD);
+			break;
+		case Opt_nossd:
+			btrfs_set_and_info(root, NOSSD,
+					     "not using ssd allocation scheme");
+			btrfs_clear_opt(info->mount_opt, SSD);
+			break;
+		case Opt_barrier:
+			btrfs_clear_and_info(root, NOBARRIER,
+					     "turning on barriers");
+			break;
+		case Opt_nobarrier:
+			btrfs_set_and_info(root, NOBARRIER,
+					   "turning off barriers");
+			break;
+		case Opt_thread_pool:
+			ret = match_int(&args[0], &intarg);
+			if (ret) {
+				goto out;
+			} else if (intarg > 0) {
+				info->thread_pool_size = intarg;
+			} else {
+				ret = -EINVAL;
+				goto out;
+			}
+			break;
+		case Opt_max_inline:
+			num = match_strdup(&args[0]);
+			if (num) {
+				info->max_inline = memparse(num, NULL);
+				kfree(num);
+
+				if (info->max_inline) {
+					info->max_inline = min_t(u64,
+						info->max_inline,
+						root->sectorsize);
+				}
+				btrfs_info(root->fs_info, "max_inline at %llu",
+					info->max_inline);
+			} else {
+				ret = -ENOMEM;
+				goto out;
+			}
+			break;
+		case Opt_alloc_start:
+			num = match_strdup(&args[0]);
+			if (num) {
+				mutex_lock(&info->chunk_mutex);
+				info->alloc_start = memparse(num, NULL);
+				mutex_unlock(&info->chunk_mutex);
+				kfree(num);
+				btrfs_info(root->fs_info, "allocations start at %llu",
+					info->alloc_start);
+			} else {
+				ret = -ENOMEM;
+				goto out;
+			}
+			break;
+		case Opt_acl:
+#ifdef CONFIG_BTRFS_FS_POSIX_ACL
+			root->fs_info->sb->s_flags |= MS_POSIXACL;
+			break;
+#else
+			btrfs_err(root->fs_info,
+				"support for ACL not compiled in!");
+			ret = -EINVAL;
+			goto out;
+#endif
+		case Opt_noacl:
+			root->fs_info->sb->s_flags &= ~MS_POSIXACL;
+			break;
+		case Opt_notreelog:
+			btrfs_set_and_info(root, NOTREELOG,
+					   "disabling tree log");
+			break;
+		case Opt_treelog:
+			btrfs_clear_and_info(root, NOTREELOG,
+					     "enabling tree log");
+			break;
+		case Opt_flushoncommit:
+			btrfs_set_and_info(root, FLUSHONCOMMIT,
+					   "turning on flush-on-commit");
+			break;
+		case Opt_noflushoncommit:
+			btrfs_clear_and_info(root, FLUSHONCOMMIT,
+					     "turning off flush-on-commit");
+			break;
+		case Opt_ratio:
+			ret = match_int(&args[0], &intarg);
+			if (ret) {
+				goto out;
+			} else if (intarg >= 0) {
+				info->metadata_ratio = intarg;
+				btrfs_info(root->fs_info, "metadata ratio %d",
+				       info->metadata_ratio);
+			} else {
+				ret = -EINVAL;
+				goto out;
+			}
+			break;
+		case Opt_discard:
+			btrfs_set_and_info(root, DISCARD,
+					   "turning on discard");
+			break;
+		case Opt_nodiscard:
+			btrfs_clear_and_info(root, DISCARD,
+					     "turning off discard");
+			break;
+		case Opt_space_cache:
+			btrfs_set_and_info(root, SPACE_CACHE,
+					   "enabling disk space caching");
+			break;
+		case Opt_rescan_uuid_tree:
+			btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
+			break;
+		case Opt_no_space_cache:
+			btrfs_clear_and_info(root, SPACE_CACHE,
+					     "disabling disk space caching");
+			break;
+		case Opt_inode_cache:
+			btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
+					   "enabling inode map caching");
+			break;
+		case Opt_noinode_cache:
+			btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
+					     "disabling inode map caching");
+			break;
+		case Opt_clear_cache:
+			btrfs_set_and_info(root, CLEAR_CACHE,
+					   "force clearing of disk cache");
+			break;
+		case Opt_user_subvol_rm_allowed:
+			btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
+			break;
+		case Opt_enospc_debug:
+			btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
+			break;
+		case Opt_noenospc_debug:
+			btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
+			break;
+		case Opt_defrag:
+			btrfs_set_and_info(root, AUTO_DEFRAG,
+					   "enabling auto defrag");
+			break;
+		case Opt_nodefrag:
+			btrfs_clear_and_info(root, AUTO_DEFRAG,
+					     "disabling auto defrag");
+			break;
+		case Opt_recovery:
+			btrfs_info(root->fs_info, "enabling auto recovery");
+			btrfs_set_opt(info->mount_opt, RECOVERY);
+			break;
+		case Opt_skip_balance:
+			btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
+			break;
+#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
+		case Opt_check_integrity_including_extent_data:
+			btrfs_info(root->fs_info,
+				   "enabling check integrity including extent data");
+			btrfs_set_opt(info->mount_opt,
+				      CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
+			btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
+			break;
+		case Opt_check_integrity:
+			btrfs_info(root->fs_info, "enabling check integrity");
+			btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
+			break;
+		case Opt_check_integrity_print_mask:
+			ret = match_int(&args[0], &intarg);
+			if (ret) {
+				goto out;
+			} else if (intarg >= 0) {
+				info->check_integrity_print_mask = intarg;
+				btrfs_info(root->fs_info, "check_integrity_print_mask 0x%x",
+				       info->check_integrity_print_mask);
+			} else {
+				ret = -EINVAL;
+				goto out;
+			}
+			break;
+#else
+		case Opt_check_integrity_including_extent_data:
+		case Opt_check_integrity:
+		case Opt_check_integrity_print_mask:
+			btrfs_err(root->fs_info,
+				"support for check_integrity* not compiled in!");
+			ret = -EINVAL;
+			goto out;
+#endif
+		case Opt_fatal_errors:
+			if (strcmp(args[0].from, "panic") == 0)
+				btrfs_set_opt(info->mount_opt,
+					      PANIC_ON_FATAL_ERROR);
+			else if (strcmp(args[0].from, "bug") == 0)
+				btrfs_clear_opt(info->mount_opt,
+					      PANIC_ON_FATAL_ERROR);
+			else {
+				ret = -EINVAL;
+				goto out;
+			}
+			break;
+		case Opt_commit_interval:
+			intarg = 0;
+			ret = match_int(&args[0], &intarg);
+			if (ret < 0) {
+				btrfs_err(root->fs_info, "invalid commit interval");
+				ret = -EINVAL;
+				goto out;
+			}
+			if (intarg > 0) {
+				if (intarg > 300) {
+					btrfs_warn(root->fs_info, "excessive commit interval %d",
+							intarg);
+				}
+				info->commit_interval = intarg;
+			} else {
+				btrfs_info(root->fs_info, "using default commit interval %ds",
+				    BTRFS_DEFAULT_COMMIT_INTERVAL);
+				info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
+			}
+			break;
+		case Opt_err:
+			btrfs_info(root->fs_info, "unrecognized mount option '%s'", p);
+			ret = -EINVAL;
+			goto out;
+		default:
+			break;
+		}
+	}
+out:
+	if (!ret && btrfs_test_opt(root, SPACE_CACHE))
+		btrfs_info(root->fs_info, "disk space caching is enabled");
+	kfree(orig);
+	return ret;
+}
+
+/*
+ * Parse mount options that are required early in the mount process.
+ *
+ * All other options will be parsed on much later in the mount process and
+ * only when we need to allocate a new super block.
+ */
+static int btrfs_parse_early_options(const char *options, fmode_t flags,
+		void *holder, char **subvol_name, u64 *subvol_objectid,
+		struct btrfs_fs_devices **fs_devices)
+{
+	substring_t args[MAX_OPT_ARGS];
+	char *device_name, *opts, *orig, *p;
+	char *num = NULL;
+	int error = 0;
+
+	if (!options)
+		return 0;
+
+	/*
+	 * strsep changes the string, duplicate it because parse_options
+	 * gets called twice
+	 */
+	opts = kstrdup(options, GFP_KERNEL);
+	if (!opts)
+		return -ENOMEM;
+	orig = opts;
+
+	while ((p = strsep(&opts, ",")) != NULL) {
+		int token;
+		if (!*p)
+			continue;
+
+		token = match_token(p, tokens, args);
+		switch (token) {
+		case Opt_subvol:
+			kfree(*subvol_name);
+			*subvol_name = match_strdup(&args[0]);
+			if (!*subvol_name) {
+				error = -ENOMEM;
+				goto out;
+			}
+			break;
+		case Opt_subvolid:
+			num = match_strdup(&args[0]);
+			if (num) {
+				*subvol_objectid = memparse(num, NULL);
+				kfree(num);
+				/* we want the original fs_tree */
+				if (!*subvol_objectid)
+					*subvol_objectid =
+						BTRFS_FS_TREE_OBJECTID;
+			} else {
+				error = -EINVAL;
+				goto out;
+			}
+			break;
+		case Opt_subvolrootid:
+			printk(KERN_WARNING
+				"BTRFS: 'subvolrootid' mount option is deprecated and has "
+				"no effect\n");
+			break;
+		case Opt_device:
+			device_name = match_strdup(&args[0]);
+			if (!device_name) {
+				error = -ENOMEM;
+				goto out;
+			}
+			error = btrfs_scan_one_device(device_name,
+					flags, holder, fs_devices);
+			kfree(device_name);
+			if (error)
+				goto out;
+			break;
+		default:
+			break;
+		}
+	}
+
+out:
+	kfree(orig);
+	return error;
+}
+
+static struct dentry *get_default_root(struct super_block *sb,
+				       u64 subvol_objectid)
+{
+	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+	struct btrfs_root *root = fs_info->tree_root;
+	struct btrfs_root *new_root;
+	struct btrfs_dir_item *di;
+	struct btrfs_path *path;
+	struct btrfs_key location;
+	struct inode *inode;
+	u64 dir_id;
+	int new = 0;
+
+	/*
+	 * We have a specific subvol we want to mount, just setup location and
+	 * go look up the root.
+	 */
+	if (subvol_objectid) {
+		location.objectid = subvol_objectid;
+		location.type = BTRFS_ROOT_ITEM_KEY;
+		location.offset = (u64)-1;
+		goto find_root;
+	}
+
+	path = btrfs_alloc_path();
+	if (!path)
+		return ERR_PTR(-ENOMEM);
+	path->leave_spinning = 1;
+
+	/*
+	 * Find the "default" dir item which points to the root item that we
+	 * will mount by default if we haven't been given a specific subvolume
+	 * to mount.
+	 */
+	dir_id = btrfs_super_root_dir(fs_info->super_copy);
+	di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
+	if (IS_ERR(di)) {
+		btrfs_free_path(path);
+		return ERR_CAST(di);
+	}
+	if (!di) {
+		/*
+		 * Ok the default dir item isn't there.  This is weird since
+		 * it's always been there, but don't freak out, just try and
+		 * mount to root most subvolume.
+		 */
+		btrfs_free_path(path);
+		dir_id = BTRFS_FIRST_FREE_OBJECTID;
+		new_root = fs_info->fs_root;
+		goto setup_root;
+	}
+
+	btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
+	btrfs_free_path(path);
+
+find_root:
+	new_root = btrfs_read_fs_root_no_name(fs_info, &location);
+	if (IS_ERR(new_root))
+		return ERR_CAST(new_root);
+
+	if (!(sb->s_flags & MS_RDONLY)) {
+		int ret;
+		down_read(&fs_info->cleanup_work_sem);
+		ret = btrfs_orphan_cleanup(new_root);
+		up_read(&fs_info->cleanup_work_sem);
+		if (ret)
+			return ERR_PTR(ret);
+	}
+
+	dir_id = btrfs_root_dirid(&new_root->root_item);
+setup_root:
+	location.objectid = dir_id;
+	location.type = BTRFS_INODE_ITEM_KEY;
+	location.offset = 0;
+
+	inode = btrfs_iget(sb, &location, new_root, &new);
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
+
+	/*
+	 * If we're just mounting the root most subvol put the inode and return
+	 * a reference to the dentry.  We will have already gotten a reference
+	 * to the inode in btrfs_fill_super so we're good to go.
+	 */
+	if (!new && d_inode(sb->s_root) == inode) {
+		iput(inode);
+		return dget(sb->s_root);
+	}
+
+	return d_obtain_root(inode);
+}
+
+static int btrfs_fill_super(struct super_block *sb,
+			    struct btrfs_fs_devices *fs_devices,
+			    void *data, int silent)
+{
+	struct inode *inode;
+	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+	struct btrfs_key key;
+	int err;
+
+	sb->s_maxbytes = MAX_LFS_FILESIZE;
+	sb->s_magic = BTRFS_SUPER_MAGIC;
+	sb->s_op = &btrfs_super_ops;
+	sb->s_d_op = &btrfs_dentry_operations;
+	sb->s_export_op = &btrfs_export_ops;
+	sb->s_xattr = btrfs_xattr_handlers;
+	sb->s_time_gran = 1;
+#ifdef CONFIG_BTRFS_FS_POSIX_ACL
+	sb->s_flags |= MS_POSIXACL;
+#endif
+	sb->s_flags |= MS_I_VERSION;
+	err = open_ctree(sb, fs_devices, (char *)data);
+	if (err) {
+		printk(KERN_ERR "BTRFS: open_ctree failed\n");
+		return err;
+	}
+
+	key.objectid = BTRFS_FIRST_FREE_OBJECTID;
+	key.type = BTRFS_INODE_ITEM_KEY;
+	key.offset = 0;
+	inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		goto fail_close;
+	}
+
+	sb->s_root = d_make_root(inode);
+	if (!sb->s_root) {
+		err = -ENOMEM;
+		goto fail_close;
+	}
+
+	save_mount_options(sb, data);
+	cleancache_init_fs(sb);
+	sb->s_flags |= MS_ACTIVE;
+	return 0;
+
+fail_close:
+	close_ctree(fs_info->tree_root);
+	return err;
+}
+
+int btrfs_sync_fs(struct super_block *sb, int wait)
+{
+	struct btrfs_trans_handle *trans;
+	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+	struct btrfs_root *root = fs_info->tree_root;
+
+	trace_btrfs_sync_fs(wait);
+
+	if (!wait) {
+		filemap_flush(fs_info->btree_inode->i_mapping);
+		return 0;
+	}
+
+	btrfs_wait_ordered_roots(fs_info, -1);
+
+	trans = btrfs_attach_transaction_barrier(root);
+	if (IS_ERR(trans)) {
+		/* no transaction, don't bother */
+		if (PTR_ERR(trans) == -ENOENT) {
+			/*
+			 * Exit unless we have some pending changes
+			 * that need to go through commit
+			 */
+			if (fs_info->pending_changes == 0)
+				return 0;
+			/*
+			 * A non-blocking test if the fs is frozen. We must not
+			 * start a new transaction here otherwise a deadlock
+			 * happens. The pending operations are delayed to the
+			 * next commit after thawing.
+			 */
+			if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
+				__sb_end_write(sb, SB_FREEZE_WRITE);
+			else
+				return 0;
+			trans = btrfs_start_transaction(root, 0);
+		}
+		if (IS_ERR(trans))
+			return PTR_ERR(trans);
+	}
+	return btrfs_commit_transaction(trans, root);
+}
+
+static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
+{
+	struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
+	struct btrfs_root *root = info->tree_root;
+	char *compress_type;
+
+	if (btrfs_test_opt(root, DEGRADED))
+		seq_puts(seq, ",degraded");
+	if (btrfs_test_opt(root, NODATASUM))
+		seq_puts(seq, ",nodatasum");
+	if (btrfs_test_opt(root, NODATACOW))
+		seq_puts(seq, ",nodatacow");
+	if (btrfs_test_opt(root, NOBARRIER))
+		seq_puts(seq, ",nobarrier");
+	if (info->max_inline != BTRFS_DEFAULT_MAX_INLINE)
+		seq_printf(seq, ",max_inline=%llu", info->max_inline);
+	if (info->alloc_start != 0)
+		seq_printf(seq, ",alloc_start=%llu", info->alloc_start);
+	if (info->thread_pool_size !=  min_t(unsigned long,
+					     num_online_cpus() + 2, 8))
+		seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
+	if (btrfs_test_opt(root, COMPRESS)) {
+		if (info->compress_type == BTRFS_COMPRESS_ZLIB)
+			compress_type = "zlib";
+		else
+			compress_type = "lzo";
+		if (btrfs_test_opt(root, FORCE_COMPRESS))
+			seq_printf(seq, ",compress-force=%s", compress_type);
+		else
+			seq_printf(seq, ",compress=%s", compress_type);
+	}
+	if (btrfs_test_opt(root, NOSSD))
+		seq_puts(seq, ",nossd");
+	if (btrfs_test_opt(root, SSD_SPREAD))
+		seq_puts(seq, ",ssd_spread");
+	else if (btrfs_test_opt(root, SSD))
+		seq_puts(seq, ",ssd");
+	if (btrfs_test_opt(root, NOTREELOG))
+		seq_puts(seq, ",notreelog");
+	if (btrfs_test_opt(root, FLUSHONCOMMIT))
+		seq_puts(seq, ",flushoncommit");
+	if (btrfs_test_opt(root, DISCARD))
+		seq_puts(seq, ",discard");
+	if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
+		seq_puts(seq, ",noacl");
+	if (btrfs_test_opt(root, SPACE_CACHE))
+		seq_puts(seq, ",space_cache");
+	else
+		seq_puts(seq, ",nospace_cache");
+	if (btrfs_test_opt(root, RESCAN_UUID_TREE))
+		seq_puts(seq, ",rescan_uuid_tree");
+	if (btrfs_test_opt(root, CLEAR_CACHE))
+		seq_puts(seq, ",clear_cache");
+	if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
+		seq_puts(seq, ",user_subvol_rm_allowed");
+	if (btrfs_test_opt(root, ENOSPC_DEBUG))
+		seq_puts(seq, ",enospc_debug");
+	if (btrfs_test_opt(root, AUTO_DEFRAG))
+		seq_puts(seq, ",autodefrag");
+	if (btrfs_test_opt(root, INODE_MAP_CACHE))
+		seq_puts(seq, ",inode_cache");
+	if (btrfs_test_opt(root, SKIP_BALANCE))
+		seq_puts(seq, ",skip_balance");
+	if (btrfs_test_opt(root, RECOVERY))
+		seq_puts(seq, ",recovery");
+#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
+	if (btrfs_test_opt(root, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
+		seq_puts(seq, ",check_int_data");
+	else if (btrfs_test_opt(root, CHECK_INTEGRITY))
+		seq_puts(seq, ",check_int");
+	if (info->check_integrity_print_mask)
+		seq_printf(seq, ",check_int_print_mask=%d",
+				info->check_integrity_print_mask);
+#endif
+	if (info->metadata_ratio)
+		seq_printf(seq, ",metadata_ratio=%d",
+				info->metadata_ratio);
+	if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
+		seq_puts(seq, ",fatal_errors=panic");
+	if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
+		seq_printf(seq, ",commit=%d", info->commit_interval);
+	return 0;
+}
+
+static int btrfs_test_super(struct super_block *s, void *data)
+{
+	struct btrfs_fs_info *p = data;
+	struct btrfs_fs_info *fs_info = btrfs_sb(s);
+
+	return fs_info->fs_devices == p->fs_devices;
+}
+
+static int btrfs_set_super(struct super_block *s, void *data)
+{
+	int err = set_anon_super(s, data);
+	if (!err)
+		s->s_fs_info = data;
+	return err;
+}
+
+/*
+ * subvolumes are identified by ino 256
+ */
+static inline int is_subvolume_inode(struct inode *inode)
+{
+	if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
+		return 1;
+	return 0;
+}
+
+/*
+ * This will strip out the subvol=%s argument for an argument string and add
+ * subvolid=0 to make sure we get the actual tree root for path walking to the
+ * subvol we want.
+ */
+static char *setup_root_args(char *args)
+{
+	unsigned len = strlen(args) + 2 + 1;
+	char *src, *dst, *buf;
+
+	/*
+	 * We need the same args as before, but with this substitution:
+	 * s!subvol=[^,]+!subvolid=0!
+	 *
+	 * Since the replacement string is up to 2 bytes longer than the
+	 * original, allocate strlen(args) + 2 + 1 bytes.
+	 */
+
+	src = strstr(args, "subvol=");
+	/* This shouldn't happen, but just in case.. */
+	if (!src)
+		return NULL;
+
+	buf = dst = kmalloc(len, GFP_NOFS);
+	if (!buf)
+		return NULL;
+
+	/*
+	 * If the subvol= arg is not at the start of the string,
+	 * copy whatever precedes it into buf.
+	 */
+	if (src != args) {
+		*src++ = '\0';
+		strcpy(buf, args);
+		dst += strlen(args);
+	}
+
+	strcpy(dst, "subvolid=0");
+	dst += strlen("subvolid=0");
+
+	/*
+	 * If there is a "," after the original subvol=... string,
+	 * copy that suffix into our buffer.  Otherwise, we're done.
+	 */
+	src = strchr(src, ',');
+	if (src)
+		strcpy(dst, src);
+
+	return buf;
+}
+
+static struct dentry *mount_subvol(const char *subvol_name, int flags,
+				   const char *device_name, char *data)
+{
+	struct dentry *root;
+	struct vfsmount *mnt;
+	char *newargs;
+
+	newargs = setup_root_args(data);
+	if (!newargs)
+		return ERR_PTR(-ENOMEM);
+	mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
+			     newargs);
+
+	if (PTR_RET(mnt) == -EBUSY) {
+		if (flags & MS_RDONLY) {
+			mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY, device_name,
+					     newargs);
+		} else {
+			int r;
+			mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY, device_name,
+					     newargs);
+			if (IS_ERR(mnt)) {
+				kfree(newargs);
+				return ERR_CAST(mnt);
+			}
+
+			r = btrfs_remount(mnt->mnt_sb, &flags, NULL);
+			if (r < 0) {
+				/* FIXME: release vfsmount mnt ??*/
+				kfree(newargs);
+				return ERR_PTR(r);
+			}
+		}
+	}
+
+	kfree(newargs);
+
+	if (IS_ERR(mnt))
+		return ERR_CAST(mnt);
+
+	root = mount_subtree(mnt, subvol_name);
+
+	if (!IS_ERR(root) && !is_subvolume_inode(d_inode(root))) {
+		struct super_block *s = root->d_sb;
+		dput(root);
+		root = ERR_PTR(-EINVAL);
+		deactivate_locked_super(s);
+		printk(KERN_ERR "BTRFS: '%s' is not a valid subvolume\n",
+				subvol_name);
+	}
+
+	return root;
+}
+
+static int parse_security_options(char *orig_opts,
+				  struct security_mnt_opts *sec_opts)
+{
+	char *secdata = NULL;
+	int ret = 0;
+
+	secdata = alloc_secdata();
+	if (!secdata)
+		return -ENOMEM;
+	ret = security_sb_copy_data(orig_opts, secdata);
+	if (ret) {
+		free_secdata(secdata);
+		return ret;
+	}
+	ret = security_sb_parse_opts_str(secdata, sec_opts);
+	free_secdata(secdata);
+	return ret;
+}
+
+static int setup_security_options(struct btrfs_fs_info *fs_info,
+				  struct super_block *sb,
+				  struct security_mnt_opts *sec_opts)
+{
+	int ret = 0;
+
+	/*
+	 * Call security_sb_set_mnt_opts() to check whether new sec_opts
+	 * is valid.
+	 */
+	ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
+	if (ret)
+		return ret;
+
+#ifdef CONFIG_SECURITY
+	if (!fs_info->security_opts.num_mnt_opts) {
+		/* first time security setup, copy sec_opts to fs_info */
+		memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
+	} else {
+		/*
+		 * Since SELinux(the only one supports security_mnt_opts) does
+		 * NOT support changing context during remount/mount same sb,
+		 * This must be the same or part of the same security options,
+		 * just free it.
+		 */
+		security_free_mnt_opts(sec_opts);
+	}
+#endif
+	return ret;
+}
+
+/*
+ * Find a superblock for the given device / mount point.
+ *
+ * Note:  This is based on get_sb_bdev from fs/super.c with a few additions
+ *	  for multiple device setup.  Make sure to keep it in sync.
+ */
+static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
+		const char *device_name, void *data)
+{
+	struct block_device *bdev = NULL;
+	struct super_block *s;
+	struct dentry *root;
+	struct btrfs_fs_devices *fs_devices = NULL;
+	struct btrfs_fs_info *fs_info = NULL;
+	struct security_mnt_opts new_sec_opts;
+	fmode_t mode = FMODE_READ;
+	char *subvol_name = NULL;
+	u64 subvol_objectid = 0;
+	int error = 0;
+
+	if (!(flags & MS_RDONLY))
+		mode |= FMODE_WRITE;
+
+	error = btrfs_parse_early_options(data, mode, fs_type,
+					  &subvol_name, &subvol_objectid,
+					  &fs_devices);
+	if (error) {
+		kfree(subvol_name);
+		return ERR_PTR(error);
+	}
+
+	if (subvol_name) {
+		root = mount_subvol(subvol_name, flags, device_name, data);
+		kfree(subvol_name);
+		return root;
+	}
+
+	security_init_mnt_opts(&new_sec_opts);
+	if (data) {
+		error = parse_security_options(data, &new_sec_opts);
+		if (error)
+			return ERR_PTR(error);
+	}
+
+	error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
+	if (error)
+		goto error_sec_opts;
+
+	/*
+	 * Setup a dummy root and fs_info for test/set super.  This is because
+	 * we don't actually fill this stuff out until open_ctree, but we need
+	 * it for searching for existing supers, so this lets us do that and
+	 * then open_ctree will properly initialize everything later.
+	 */
+	fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
+	if (!fs_info) {
+		error = -ENOMEM;
+		goto error_sec_opts;
+	}
+
+	fs_info->fs_devices = fs_devices;
+
+	fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
+	fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
+	security_init_mnt_opts(&fs_info->security_opts);
+	if (!fs_info->super_copy || !fs_info->super_for_commit) {
+		error = -ENOMEM;
+		goto error_fs_info;
+	}
+
+	error = btrfs_open_devices(fs_devices, mode, fs_type);
+	if (error)
+		goto error_fs_info;
+
+	if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
+		error = -EACCES;
+		goto error_close_devices;
+	}
+
+	bdev = fs_devices->latest_bdev;
+	s = sget(fs_type, btrfs_test_super, btrfs_set_super, flags | MS_NOSEC,
+		 fs_info);
+	if (IS_ERR(s)) {
+		error = PTR_ERR(s);
+		goto error_close_devices;
+	}
+
+	if (s->s_root) {
+		btrfs_close_devices(fs_devices);
+		free_fs_info(fs_info);
+		if ((flags ^ s->s_flags) & MS_RDONLY)
+			error = -EBUSY;
+	} else {
+		char b[BDEVNAME_SIZE];
+
+		strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
+		btrfs_sb(s)->bdev_holder = fs_type;
+		error = btrfs_fill_super(s, fs_devices, data,
+					 flags & MS_SILENT ? 1 : 0);
+	}
+
+	root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error);
+	if (IS_ERR(root)) {
+		deactivate_locked_super(s);
+		error = PTR_ERR(root);
+		goto error_sec_opts;
+	}
+
+	fs_info = btrfs_sb(s);
+	error = setup_security_options(fs_info, s, &new_sec_opts);
+	if (error) {
+		dput(root);
+		deactivate_locked_super(s);
+		goto error_sec_opts;
+	}
+
+	return root;
+
+error_close_devices:
+	btrfs_close_devices(fs_devices);
+error_fs_info:
+	free_fs_info(fs_info);
+error_sec_opts:
+	security_free_mnt_opts(&new_sec_opts);
+	return ERR_PTR(error);
+}
+
+static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
+				     int new_pool_size, int old_pool_size)
+{
+	if (new_pool_size == old_pool_size)
+		return;
+
+	fs_info->thread_pool_size = new_pool_size;
+
+	btrfs_info(fs_info, "resize thread pool %d -> %d",
+	       old_pool_size, new_pool_size);
+
+	btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
+				new_pool_size);
+	btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
+	btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
+				new_pool_size);
+}
+
+static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
+{
+	set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
+}
+
+static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
+				       unsigned long old_opts, int flags)
+{
+	if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
+	    (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
+	     (flags & MS_RDONLY))) {
+		/* wait for any defraggers to finish */
+		wait_event(fs_info->transaction_wait,
+			   (atomic_read(&fs_info->defrag_running) == 0));
+		if (flags & MS_RDONLY)
+			sync_filesystem(fs_info->sb);
+	}
+}
+
+static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
+					 unsigned long old_opts)
+{
+	/*
+	 * We need cleanup all defragable inodes if the autodefragment is
+	 * close or the fs is R/O.
+	 */
+	if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
+	    (!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
+	     (fs_info->sb->s_flags & MS_RDONLY))) {
+		btrfs_cleanup_defrag_inodes(fs_info);
+	}
+
+	clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
+}
+
+static int btrfs_remount(struct super_block *sb, int *flags, char *data)
+{
+	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+	struct btrfs_root *root = fs_info->tree_root;
+	unsigned old_flags = sb->s_flags;
+	unsigned long old_opts = fs_info->mount_opt;
+	unsigned long old_compress_type = fs_info->compress_type;
+	u64 old_max_inline = fs_info->max_inline;
+	u64 old_alloc_start = fs_info->alloc_start;
+	int old_thread_pool_size = fs_info->thread_pool_size;
+	unsigned int old_metadata_ratio = fs_info->metadata_ratio;
+	int ret;
+
+	sync_filesystem(sb);
+	btrfs_remount_prepare(fs_info);
+
+	if (data) {
+		struct security_mnt_opts new_sec_opts;
+
+		security_init_mnt_opts(&new_sec_opts);
+		ret = parse_security_options(data, &new_sec_opts);
+		if (ret)
+			goto restore;
+		ret = setup_security_options(fs_info, sb,
+					     &new_sec_opts);
+		if (ret) {
+			security_free_mnt_opts(&new_sec_opts);
+			goto restore;
+		}
+	}
+
+	ret = btrfs_parse_options(root, data);
+	if (ret) {
+		ret = -EINVAL;
+		goto restore;
+	}
+
+	btrfs_remount_begin(fs_info, old_opts, *flags);
+	btrfs_resize_thread_pool(fs_info,
+		fs_info->thread_pool_size, old_thread_pool_size);
+
+	if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
+		goto out;
+
+	if (*flags & MS_RDONLY) {
+		/*
+		 * this also happens on 'umount -rf' or on shutdown, when
+		 * the filesystem is busy.
+		 */
+		cancel_work_sync(&fs_info->async_reclaim_work);
+
+		/* wait for the uuid_scan task to finish */
+		down(&fs_info->uuid_tree_rescan_sem);
+		/* avoid complains from lockdep et al. */
+		up(&fs_info->uuid_tree_rescan_sem);
+
+		sb->s_flags |= MS_RDONLY;
+
+		btrfs_dev_replace_suspend_for_unmount(fs_info);
+		btrfs_scrub_cancel(fs_info);
+		btrfs_pause_balance(fs_info);
+
+		ret = btrfs_commit_super(root);
+		if (ret)
+			goto restore;
+	} else {
+		if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
+			btrfs_err(fs_info,
+				"Remounting read-write after error is not allowed");
+			ret = -EINVAL;
+			goto restore;
+		}
+		if (fs_info->fs_devices->rw_devices == 0) {
+			ret = -EACCES;
+			goto restore;
+		}
+
+		if (fs_info->fs_devices->missing_devices >
+		     fs_info->num_tolerated_disk_barrier_failures &&
+		    !(*flags & MS_RDONLY)) {
+			btrfs_warn(fs_info,
+				"too many missing devices, writeable remount is not allowed");
+			ret = -EACCES;
+			goto restore;
+		}
+
+		if (btrfs_super_log_root(fs_info->super_copy) != 0) {
+			ret = -EINVAL;
+			goto restore;
+		}
+
+		ret = btrfs_cleanup_fs_roots(fs_info);
+		if (ret)
+			goto restore;
+
+		/* recover relocation */
+		mutex_lock(&fs_info->cleaner_mutex);
+		ret = btrfs_recover_relocation(root);
+		mutex_unlock(&fs_info->cleaner_mutex);
+		if (ret)
+			goto restore;
+
+		ret = btrfs_resume_balance_async(fs_info);
+		if (ret)
+			goto restore;
+
+		ret = btrfs_resume_dev_replace_async(fs_info);
+		if (ret) {
+			btrfs_warn(fs_info, "failed to resume dev_replace");
+			goto restore;
+		}
+
+		if (!fs_info->uuid_root) {
+			btrfs_info(fs_info, "creating UUID tree");
+			ret = btrfs_create_uuid_tree(fs_info);
+			if (ret) {
+				btrfs_warn(fs_info, "failed to create the UUID tree %d", ret);
+				goto restore;
+			}
+		}
+		sb->s_flags &= ~MS_RDONLY;
+	}
+out:
+	wake_up_process(fs_info->transaction_kthread);
+	btrfs_remount_cleanup(fs_info, old_opts);
+	return 0;
+
+restore:
+	/* We've hit an error - don't reset MS_RDONLY */
+	if (sb->s_flags & MS_RDONLY)
+		old_flags |= MS_RDONLY;
+	sb->s_flags = old_flags;
+	fs_info->mount_opt = old_opts;
+	fs_info->compress_type = old_compress_type;
+	fs_info->max_inline = old_max_inline;
+	mutex_lock(&fs_info->chunk_mutex);
+	fs_info->alloc_start = old_alloc_start;
+	mutex_unlock(&fs_info->chunk_mutex);
+	btrfs_resize_thread_pool(fs_info,
+		old_thread_pool_size, fs_info->thread_pool_size);
+	fs_info->metadata_ratio = old_metadata_ratio;
+	btrfs_remount_cleanup(fs_info, old_opts);
+	return ret;
+}
+
+/* Used to sort the devices by max_avail(descending sort) */
+static int btrfs_cmp_device_free_bytes(const void *dev_info1,
+				       const void *dev_info2)
+{
+	if (((struct btrfs_device_info *)dev_info1)->max_avail >
+	    ((struct btrfs_device_info *)dev_info2)->max_avail)
+		return -1;
+	else if (((struct btrfs_device_info *)dev_info1)->max_avail <
+		 ((struct btrfs_device_info *)dev_info2)->max_avail)
+		return 1;
+	else
+	return 0;
+}
+
+/*
+ * sort the devices by max_avail, in which max free extent size of each device
+ * is stored.(Descending Sort)
+ */
+static inline void btrfs_descending_sort_devices(
+					struct btrfs_device_info *devices,
+					size_t nr_devices)
+{
+	sort(devices, nr_devices, sizeof(struct btrfs_device_info),
+	     btrfs_cmp_device_free_bytes, NULL);
+}
+
+/*
+ * The helper to calc the free space on the devices that can be used to store
+ * file data.
+ */
+static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
+{
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct btrfs_device_info *devices_info;
+	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
+	struct btrfs_device *device;
+	u64 skip_space;
+	u64 type;
+	u64 avail_space;
+	u64 used_space;
+	u64 min_stripe_size;
+	int min_stripes = 1, num_stripes = 1;
+	int i = 0, nr_devices;
+	int ret;
+
+	/*
+	 * We aren't under the device list lock, so this is racey-ish, but good
+	 * enough for our purposes.
+	 */
+	nr_devices = fs_info->fs_devices->open_devices;
+	if (!nr_devices) {
+		smp_mb();
+		nr_devices = fs_info->fs_devices->open_devices;
+		ASSERT(nr_devices);
+		if (!nr_devices) {
+			*free_bytes = 0;
+			return 0;
+		}
+	}
+
+	devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
+			       GFP_NOFS);
+	if (!devices_info)
+		return -ENOMEM;
+
+	/* calc min stripe number for data space alloction */
+	type = btrfs_get_alloc_profile(root, 1);
+	if (type & BTRFS_BLOCK_GROUP_RAID0) {
+		min_stripes = 2;
+		num_stripes = nr_devices;
+	} else if (type & BTRFS_BLOCK_GROUP_RAID1) {
+		min_stripes = 2;
+		num_stripes = 2;
+	} else if (type & BTRFS_BLOCK_GROUP_RAID10) {
+		min_stripes = 4;
+		num_stripes = 4;
+	}
+
+	if (type & BTRFS_BLOCK_GROUP_DUP)
+		min_stripe_size = 2 * BTRFS_STRIPE_LEN;
+	else
+		min_stripe_size = BTRFS_STRIPE_LEN;
+
+	if (fs_info->alloc_start)
+		mutex_lock(&fs_devices->device_list_mutex);
+	rcu_read_lock();
+	list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
+		if (!device->in_fs_metadata || !device->bdev ||
+		    device->is_tgtdev_for_dev_replace)
+			continue;
+
+		if (i >= nr_devices)
+			break;
+
+		avail_space = device->total_bytes - device->bytes_used;
+
+		/* align with stripe_len */
+		avail_space = div_u64(avail_space, BTRFS_STRIPE_LEN);
+		avail_space *= BTRFS_STRIPE_LEN;
+
+		/*
+		 * In order to avoid overwritting the superblock on the drive,
+		 * btrfs starts at an offset of at least 1MB when doing chunk
+		 * allocation.
+		 */
+		skip_space = 1024 * 1024;
+
+		/* user can set the offset in fs_info->alloc_start. */
+		if (fs_info->alloc_start &&
+		    fs_info->alloc_start + BTRFS_STRIPE_LEN <=
+		    device->total_bytes) {
+			rcu_read_unlock();
+			skip_space = max(fs_info->alloc_start, skip_space);
+
+			/*
+			 * btrfs can not use the free space in
+			 * [0, skip_space - 1], we must subtract it from the
+			 * total. In order to implement it, we account the used
+			 * space in this range first.
+			 */
+			ret = btrfs_account_dev_extents_size(device, 0,
+							     skip_space - 1,
+							     &used_space);
+			if (ret) {
+				kfree(devices_info);
+				mutex_unlock(&fs_devices->device_list_mutex);
+				return ret;
+			}
+
+			rcu_read_lock();
+
+			/* calc the free space in [0, skip_space - 1] */
+			skip_space -= used_space;
+		}
+
+		/*
+		 * we can use the free space in [0, skip_space - 1], subtract
+		 * it from the total.
+		 */
+		if (avail_space && avail_space >= skip_space)
+			avail_space -= skip_space;
+		else
+			avail_space = 0;
+
+		if (avail_space < min_stripe_size)
+			continue;
+
+		devices_info[i].dev = device;
+		devices_info[i].max_avail = avail_space;
+
+		i++;
+	}
+	rcu_read_unlock();
+	if (fs_info->alloc_start)
+		mutex_unlock(&fs_devices->device_list_mutex);
+
+	nr_devices = i;
+
+	btrfs_descending_sort_devices(devices_info, nr_devices);
+
+	i = nr_devices - 1;
+	avail_space = 0;
+	while (nr_devices >= min_stripes) {
+		if (num_stripes > nr_devices)
+			num_stripes = nr_devices;
+
+		if (devices_info[i].max_avail >= min_stripe_size) {
+			int j;
+			u64 alloc_size;
+
+			avail_space += devices_info[i].max_avail * num_stripes;
+			alloc_size = devices_info[i].max_avail;
+			for (j = i + 1 - num_stripes; j <= i; j++)
+				devices_info[j].max_avail -= alloc_size;
+		}
+		i--;
+		nr_devices--;
+	}
+
+	kfree(devices_info);
+	*free_bytes = avail_space;
+	return 0;
+}
+
+/*
+ * Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
+ *
+ * If there's a redundant raid level at DATA block groups, use the respective
+ * multiplier to scale the sizes.
+ *
+ * Unused device space usage is based on simulating the chunk allocator
+ * algorithm that respects the device sizes, order of allocations and the
+ * 'alloc_start' value, this is a close approximation of the actual use but
+ * there are other factors that may change the result (like a new metadata
+ * chunk).
+ *
+ * FIXME: not accurate for mixed block groups, total and free/used are ok,
+ * available appears slightly larger.
+ */
+static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
+	struct btrfs_super_block *disk_super = fs_info->super_copy;
+	struct list_head *head = &fs_info->space_info;
+	struct btrfs_space_info *found;
+	u64 total_used = 0;
+	u64 total_free_data = 0;
+	int bits = dentry->d_sb->s_blocksize_bits;
+	__be32 *fsid = (__be32 *)fs_info->fsid;
+	unsigned factor = 1;
+	struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
+	int ret;
+
+	/*
+	 * holding chunk_muext to avoid allocating new chunks, holding
+	 * device_list_mutex to avoid the device being removed
+	 */
+	rcu_read_lock();
+	list_for_each_entry_rcu(found, head, list) {
+		if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
+			int i;
+
+			total_free_data += found->disk_total - found->disk_used;
+			total_free_data -=
+				btrfs_account_ro_block_groups_free_space(found);
+
+			for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
+				if (!list_empty(&found->block_groups[i])) {
+					switch (i) {
+					case BTRFS_RAID_DUP:
+					case BTRFS_RAID_RAID1:
+					case BTRFS_RAID_RAID10:
+						factor = 2;
+					}
+				}
+			}
+		}
+
+		total_used += found->disk_used;
+	}
+
+	rcu_read_unlock();
+
+	buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
+	buf->f_blocks >>= bits;
+	buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
+
+	/* Account global block reserve as used, it's in logical size already */
+	spin_lock(&block_rsv->lock);
+	buf->f_bfree -= block_rsv->size >> bits;
+	spin_unlock(&block_rsv->lock);
+
+	buf->f_bavail = div_u64(total_free_data, factor);
+	ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
+	if (ret)
+		return ret;
+	buf->f_bavail += div_u64(total_free_data, factor);
+	buf->f_bavail = buf->f_bavail >> bits;
+
+	buf->f_type = BTRFS_SUPER_MAGIC;
+	buf->f_bsize = dentry->d_sb->s_blocksize;
+	buf->f_namelen = BTRFS_NAME_LEN;
+
+	/* We treat it as constant endianness (it doesn't matter _which_)
+	   because we want the fsid to come out the same whether mounted
+	   on a big-endian or little-endian host */
+	buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
+	buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
+	/* Mask in the root object ID too, to disambiguate subvols */
+	buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
+	buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
+
+	return 0;
+}
+
+static void btrfs_kill_super(struct super_block *sb)
+{
+	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+	kill_anon_super(sb);
+	free_fs_info(fs_info);
+}
+
+static struct file_system_type btrfs_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "btrfs",
+	.mount		= btrfs_mount,
+	.kill_sb	= btrfs_kill_super,
+	.fs_flags	= FS_REQUIRES_DEV | FS_BINARY_MOUNTDATA,
+};
+MODULE_ALIAS_FS("btrfs");
+
+static int btrfs_control_open(struct inode *inode, struct file *file)
+{
+	/*
+	 * The control file's private_data is used to hold the
+	 * transaction when it is started and is used to keep
+	 * track of whether a transaction is already in progress.
+	 */
+	file->private_data = NULL;
+	return 0;
+}
+
+/*
+ * used by btrfsctl to scan devices when no FS is mounted
+ */
+static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
+				unsigned long arg)
+{
+	struct btrfs_ioctl_vol_args *vol;
+	struct btrfs_fs_devices *fs_devices;
+	int ret = -ENOTTY;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	vol = memdup_user((void __user *)arg, sizeof(*vol));
+	if (IS_ERR(vol))
+		return PTR_ERR(vol);
+
+	switch (cmd) {
+	case BTRFS_IOC_SCAN_DEV:
+		ret = btrfs_scan_one_device(vol->name, FMODE_READ,
+					    &btrfs_fs_type, &fs_devices);
+		break;
+	case BTRFS_IOC_DEVICES_READY:
+		ret = btrfs_scan_one_device(vol->name, FMODE_READ,
+					    &btrfs_fs_type, &fs_devices);
+		if (ret)
+			break;
+		ret = !(fs_devices->num_devices == fs_devices->total_devices);
+		break;
+	}
+
+	kfree(vol);
+	return ret;
+}
+
+static int btrfs_freeze(struct super_block *sb)
+{
+	struct btrfs_trans_handle *trans;
+	struct btrfs_root *root = btrfs_sb(sb)->tree_root;
+
+	trans = btrfs_attach_transaction_barrier(root);
+	if (IS_ERR(trans)) {
+		/* no transaction, don't bother */
+		if (PTR_ERR(trans) == -ENOENT)
+			return 0;
+		return PTR_ERR(trans);
+	}
+	return btrfs_commit_transaction(trans, root);
+}
+
+static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
+{
+	struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
+	struct btrfs_fs_devices *cur_devices;
+	struct btrfs_device *dev, *first_dev = NULL;
+	struct list_head *head;
+	struct rcu_string *name;
+
+	mutex_lock(&fs_info->fs_devices->device_list_mutex);
+	cur_devices = fs_info->fs_devices;
+	while (cur_devices) {
+		head = &cur_devices->devices;
+		list_for_each_entry(dev, head, dev_list) {
+			if (dev->missing)
+				continue;
+			if (!dev->name)
+				continue;
+			if (!first_dev || dev->devid < first_dev->devid)
+				first_dev = dev;
+		}
+		cur_devices = cur_devices->seed;
+	}
+
+	if (first_dev) {
+		rcu_read_lock();
+		name = rcu_dereference(first_dev->name);
+		seq_escape(m, name->str, " \t\n\\");
+		rcu_read_unlock();
+	} else {
+		WARN_ON(1);
+	}
+	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
+	return 0;
+}
+
+static const struct super_operations btrfs_super_ops = {
+	.drop_inode	= btrfs_drop_inode,
+	.evict_inode	= btrfs_evict_inode,
+	.put_super	= btrfs_put_super,
+	.sync_fs	= btrfs_sync_fs,
+	.show_options	= btrfs_show_options,
+	.show_devname	= btrfs_show_devname,
+	.write_inode	= btrfs_write_inode,
+	.alloc_inode	= btrfs_alloc_inode,
+	.destroy_inode	= btrfs_destroy_inode,
+	.statfs		= btrfs_statfs,
+	.remount_fs	= btrfs_remount,
+	.freeze_fs	= btrfs_freeze,
+};
+
+static const struct file_operations btrfs_ctl_fops = {
+	.open = btrfs_control_open,
+	.unlocked_ioctl	 = btrfs_control_ioctl,
+	.compat_ioctl = btrfs_control_ioctl,
+	.owner	 = THIS_MODULE,
+	.llseek = noop_llseek,
+};
+
+static struct miscdevice btrfs_misc = {
+	.minor		= BTRFS_MINOR,
+	.name		= "btrfs-control",
+	.fops		= &btrfs_ctl_fops
+};
+
+MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
+MODULE_ALIAS("devname:btrfs-control");
+
+static int btrfs_interface_init(void)
+{
+	return misc_register(&btrfs_misc);
+}
+
+static void btrfs_interface_exit(void)
+{
+	if (misc_deregister(&btrfs_misc) < 0)
+		printk(KERN_INFO "BTRFS: misc_deregister failed for control device\n");
+}
+
+static void btrfs_print_info(void)
+{
+	printk(KERN_INFO "Btrfs loaded"
+#ifdef CONFIG_BTRFS_DEBUG
+			", debug=on"
+#endif
+#ifdef CONFIG_BTRFS_ASSERT
+			", assert=on"
+#endif
+#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
+			", integrity-checker=on"
+#endif
+			"\n");
+}
+
+static int btrfs_run_sanity_tests(void)
+{
+	int ret;
+
+	ret = btrfs_init_test_fs();
+	if (ret)
+		return ret;
+
+	ret = btrfs_test_free_space_cache();
+	if (ret)
+		goto out;
+	ret = btrfs_test_extent_buffer_operations();
+	if (ret)
+		goto out;
+	ret = btrfs_test_extent_io();
+	if (ret)
+		goto out;
+	ret = btrfs_test_inodes();
+	if (ret)
+		goto out;
+	ret = btrfs_test_qgroups();
+out:
+	btrfs_destroy_test_fs();
+	return ret;
+}
+
+static int __init init_btrfs_fs(void)
+{
+	int err;
+
+	err = btrfs_hash_init();
+	if (err)
+		return err;
+
+	btrfs_props_init();
+
+	err = btrfs_init_sysfs();
+	if (err)
+		goto free_hash;
+
+	btrfs_init_compress();
+
+	err = btrfs_init_cachep();
+	if (err)
+		goto free_compress;
+
+	err = extent_io_init();
+	if (err)
+		goto free_cachep;
+
+	err = extent_map_init();
+	if (err)
+		goto free_extent_io;
+
+	err = ordered_data_init();
+	if (err)
+		goto free_extent_map;
+
+	err = btrfs_delayed_inode_init();
+	if (err)
+		goto free_ordered_data;
+
+	err = btrfs_auto_defrag_init();
+	if (err)
+		goto free_delayed_inode;
+
+	err = btrfs_delayed_ref_init();
+	if (err)
+		goto free_auto_defrag;
+
+	err = btrfs_prelim_ref_init();
+	if (err)
+		goto free_delayed_ref;
+
+	err = btrfs_end_io_wq_init();
+	if (err)
+		goto free_prelim_ref;
+
+	err = btrfs_interface_init();
+	if (err)
+		goto free_end_io_wq;
+
+	btrfs_init_lockdep();
+
+	btrfs_print_info();
+
+	err = btrfs_run_sanity_tests();
+	if (err)
+		goto unregister_ioctl;
+
+	err = register_filesystem(&btrfs_fs_type);
+	if (err)
+		goto unregister_ioctl;
+
+	return 0;
+
+unregister_ioctl:
+	btrfs_interface_exit();
+free_end_io_wq:
+	btrfs_end_io_wq_exit();
+free_prelim_ref:
+	btrfs_prelim_ref_exit();
+free_delayed_ref:
+	btrfs_delayed_ref_exit();
+free_auto_defrag:
+	btrfs_auto_defrag_exit();
+free_delayed_inode:
+	btrfs_delayed_inode_exit();
+free_ordered_data:
+	ordered_data_exit();
+free_extent_map:
+	extent_map_exit();
+free_extent_io:
+	extent_io_exit();
+free_cachep:
+	btrfs_destroy_cachep();
+free_compress:
+	btrfs_exit_compress();
+	btrfs_exit_sysfs();
+free_hash:
+	btrfs_hash_exit();
+	return err;
+}
+
+static void __exit exit_btrfs_fs(void)
+{
+	btrfs_destroy_cachep();
+	btrfs_delayed_ref_exit();
+	btrfs_auto_defrag_exit();
+	btrfs_delayed_inode_exit();
+	btrfs_prelim_ref_exit();
+	ordered_data_exit();
+	extent_map_exit();
+	extent_io_exit();
+	btrfs_interface_exit();
+	btrfs_end_io_wq_exit();
+	unregister_filesystem(&btrfs_fs_type);
+	btrfs_exit_sysfs();
+	btrfs_cleanup_fs_uuids();
+	btrfs_exit_compress();
+	btrfs_hash_exit();
+}
+
+late_initcall(init_btrfs_fs);
+module_exit(exit_btrfs_fs)
+
+MODULE_LICENSE("GPL");