Commit 96da0919 authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: Introduce new mount option to disable tree log replay 



Introduce a new mount option "nologreplay" to co-operate with "ro" mount
option to get real readonly mount, like "norecovery" in ext* and xfs.

Since the new parse_options() need to check new flags at remount time,
so add a new parameter for parse_options().

Signed-off-by: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: default avatarChandan Rajendra <chandan@linux.vnet.ibm.com>
Tested-by: default avatarAustin S. Hemmelgarn <ahferroin7@gmail.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 8dcddfa0

Documentation/filesystems/btrfs.txt

+8 −0
Original line number Diff line number Diff line
@@ -168,6 +168,14 @@ Options with (*) are default options and will not show in the mount options. 
  notreelog

	Enable/disable the tree logging used for fsync and O_SYNC writes.



  nologreplay

	Disable the log tree replay at mount time to prevent filesystem

	from getting modified.

	Must be used with 'ro' mount option.

	A filesystem mounted with this option cannot transition to a

	read-write mount via remount,rw - the filesystem must be unmounted

	and mounted back again if read-write access is desired.



  usebackuproot

	Enable attempts to use backup tree roots if a bad tree root is found at

	mount time.

fs/btrfs/ctree.h

+3 −1
Original line number Diff line number Diff line
@@ -2250,6 +2250,7 @@ struct btrfs_ioctl_defrag_range_args { 
#define BTRFS_MOUNT_FRAGMENT_DATA	(1 << 24)

#define BTRFS_MOUNT_FRAGMENT_METADATA	(1 << 25)

#define BTRFS_MOUNT_FREE_SPACE_TREE	(1 << 26)

#define BTRFS_MOUNT_NOLOGREPLAY		(1 << 27)



#define BTRFS_DEFAULT_COMMIT_INTERVAL	(30)

#define BTRFS_DEFAULT_MAX_INLINE	(8192)
@@ -4151,7 +4152,8 @@ void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info); 
ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size);



/* super.c */

int btrfs_parse_options(struct btrfs_root *root, char *options);

int btrfs_parse_options(struct btrfs_root *root, char *options,

			unsigned long new_flags);

int btrfs_sync_fs(struct super_block *sb, int wait);



#ifdef CONFIG_PRINTK

fs/btrfs/disk-io.c

+4 −3
Original line number Diff line number Diff line
@@ -2750,7 +2750,7 @@ int open_ctree(struct super_block *sb, 
	 */

	fs_info->compress_type = BTRFS_COMPRESS_ZLIB;



	ret = btrfs_parse_options(tree_root, options);

	ret = btrfs_parse_options(tree_root, options, sb->s_flags);

	if (ret) {

		err = ret;

		goto fail_alloc;
@@ -3029,8 +3029,9 @@ retry_root_backup: 
	if (ret)

		goto fail_trans_kthread;



	/* do not make disk changes in broken FS */

	if (btrfs_super_log_root(disk_super) != 0) {

	/* do not make disk changes in broken FS or nologreplay is given */

	if (btrfs_super_log_root(disk_super) != 0 &&

	    !btrfs_test_opt(tree_root, NOLOGREPLAY)) {

		ret = btrfs_replay_log(fs_info, fs_devices);

		if (ret) {

			err = ret;

fs/btrfs/super.c

+25 −3
Original line number Diff line number Diff line
@@ -304,6 +304,7 @@ enum { 
	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_usebackuproot,

	Opt_nologreplay,

#ifdef CONFIG_BTRFS_DEBUG

	Opt_fragment_data, Opt_fragment_metadata, Opt_fragment_all,

#endif
@@ -335,6 +336,7 @@ static const match_table_t tokens = { 
	{Opt_noacl, "noacl"},

	{Opt_notreelog, "notreelog"},

	{Opt_treelog, "treelog"},

	{Opt_nologreplay, "nologreplay"},

	{Opt_flushoncommit, "flushoncommit"},

	{Opt_noflushoncommit, "noflushoncommit"},

	{Opt_ratio, "metadata_ratio=%d"},
@@ -374,7 +376,8 @@ static const match_table_t tokens = { 
 * 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)

int btrfs_parse_options(struct btrfs_root *root, char *options,

			unsigned long new_flags)

{

	struct btrfs_fs_info *info = root->fs_info;

	substring_t args[MAX_OPT_ARGS];
@@ -394,8 +397,12 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) 
	else if (cache_gen)

		btrfs_set_opt(info->mount_opt, SPACE_CACHE);



	/*

	 * Even the options are empty, we still need to do extra check

	 * against new flags

	 */

	if (!options)

		goto out;

		goto check;



	/*

	 * strsep changes the string, duplicate it because parse_options
@@ -607,6 +614,10 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) 
			btrfs_clear_and_info(root, NOTREELOG,

					     "enabling tree log");

			break;

		case Opt_nologreplay:

			btrfs_set_and_info(root, NOLOGREPLAY,

					   "disabling log replay at mount time");

			break;

		case Opt_flushoncommit:

			btrfs_set_and_info(root, FLUSHONCOMMIT,

					   "turning on flush-on-commit");
@@ -797,6 +808,15 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) 
			break;

		}

	}

check:

	/*

	 * Extra check for current option against current flag

	 */

	if (btrfs_test_opt(root, NOLOGREPLAY) && !(new_flags & MS_RDONLY)) {

		btrfs_err(root->fs_info,

			  "nologreplay must be used with ro mount option");

		ret = -EINVAL;

	}

out:

	if (btrfs_fs_compat_ro(root->fs_info, FREE_SPACE_TREE) &&

	    !btrfs_test_opt(root, FREE_SPACE_TREE) &&
@@ -1207,6 +1227,8 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry) 
		seq_puts(seq, ",ssd");

	if (btrfs_test_opt(root, NOTREELOG))

		seq_puts(seq, ",notreelog");

	if (btrfs_test_opt(root, NOLOGREPLAY))

		seq_puts(seq, ",nologreplay");

	if (btrfs_test_opt(root, FLUSHONCOMMIT))

		seq_puts(seq, ",flushoncommit");

	if (btrfs_test_opt(root, DISCARD))
@@ -1688,7 +1710,7 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data) 
		}

	}



	ret = btrfs_parse_options(root, data);

	ret = btrfs_parse_options(root, data, *flags);

	if (ret) {

		ret = -EINVAL;

		goto restore;

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