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Commit b6ed73bc authored by Anand Jain's avatar Anand Jain Committed by David Sterba
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btrfs: reduce uuid_mutex critical section while scanning devices 



The generic block device lookup or cleanup does not need the uuid mutex,
that's only for the device_list_add.

Signed-off-by: default avatarAnand Jain <anand.jain@oracle.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 20a68004

fs/btrfs/volumes.c

+5 −7
Original line number Diff line number Diff line
@@ -1232,31 +1232,29 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder, 
	 */

	bytenr = btrfs_sb_offset(0);

	flags |= FMODE_EXCL;

	mutex_lock(&uuid_mutex);



	bdev = blkdev_get_by_path(path, flags, holder);

	if (IS_ERR(bdev)) {

		ret = PTR_ERR(bdev);

		goto error;

	}

	if (IS_ERR(bdev))

		return PTR_ERR(bdev);



	if (btrfs_read_disk_super(bdev, bytenr, &page, &disk_super)) {

		ret = -EINVAL;

		goto error_bdev_put;

	}



	mutex_lock(&uuid_mutex);

	device = device_list_add(path, disk_super);

	if (IS_ERR(device))

		ret = PTR_ERR(device);

	else

		*fs_devices_ret = device->fs_devices;

	mutex_unlock(&uuid_mutex);



	btrfs_release_disk_super(page);



error_bdev_put:

	blkdev_put(bdev, flags);

error:

	mutex_unlock(&uuid_mutex);



	return ret;

}