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Commit 399f7f4c authored by David Sterba's avatar David Sterba
Browse files

btrfs: reorder initialization before the mount locks uuid_mutex 



In preparation to take a big lock, move resource initialization before
the critical section. It's not obvious from the diff, the desired order
is:

- initialize mount security options
- allocate temporary fs_info
- allocate superblock buffers

Reviewed-by: default avatarAnand Jain <anand.jain@oracle.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 5139cff5

fs/btrfs/super.c

+14 −16
Original line number Diff line number Diff line
@@ -1526,14 +1526,6 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type, 
	if (!(flags & SB_RDONLY))

		mode |= FMODE_WRITE;



	mutex_lock(&uuid_mutex);

	error = btrfs_parse_early_options(data, mode, fs_type,

					  &fs_devices);

	mutex_unlock(&uuid_mutex);

	if (error) {

		return ERR_PTR(error);

	}



	security_init_mnt_opts(&new_sec_opts);

	if (data) {

		error = parse_security_options(data, &new_sec_opts);
@@ -1541,12 +1533,6 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type, 
			return ERR_PTR(error);

	}



	mutex_lock(&uuid_mutex);

	error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);

	mutex_unlock(&uuid_mutex);

	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
@@ -1559,8 +1545,6 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type, 
		goto error_sec_opts;

	}



	fs_info->fs_devices = fs_devices;



	fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);

	fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_KERNEL);

	security_init_mnt_opts(&fs_info->security_opts);
@@ -1569,6 +1553,20 @@ static struct dentry *btrfs_mount_root(struct file_system_type *fs_type, 
		goto error_fs_info;

	}



	mutex_lock(&uuid_mutex);

	error = btrfs_parse_early_options(data, mode, fs_type, &fs_devices);

	mutex_unlock(&uuid_mutex);

	if (error)

		goto error_fs_info;



	mutex_lock(&uuid_mutex);

	error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);

	mutex_unlock(&uuid_mutex);

	if (error)

		goto error_fs_info;



	fs_info->fs_devices = fs_devices;



	mutex_lock(&uuid_mutex);

	error = btrfs_open_devices(fs_devices, mode, fs_type);

	mutex_unlock(&uuid_mutex);