Commit fc57ad8d authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: add sysfs interface for supported sectorsize 



Export supported sector sizes in /sys/fs/btrfs/features/supported_sectorsizes.

Currently all architectures have PAGE_SIZE, There's some disparity
between read-only and read-write support but that will be unified in the
future so there's only one file exporting the size.

The read-only support for systems with 64K pages also works for 4K
sector size.

This new sysfs interface would help eg. mkfs.btrfs to print more
accurate warnings about potentially incompatible option combinations.

Reviewed-by: default avatarAnand Jain <anand.jain@oracle.com>
Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent ace75066

fs/btrfs/sysfs.c

+15 −0
Original line number Diff line number Diff line
@@ -360,11 +360,26 @@ static ssize_t supported_rescue_options_show(struct kobject *kobj, 
BTRFS_ATTR(static_feature, supported_rescue_options,

	   supported_rescue_options_show);



static ssize_t supported_sectorsizes_show(struct kobject *kobj,

					  struct kobj_attribute *a,

					  char *buf)

{

	ssize_t ret = 0;



	/* Only sectorsize == PAGE_SIZE is now supported */

	ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%lu\n", PAGE_SIZE);



	return ret;

}

BTRFS_ATTR(static_feature, supported_sectorsizes,

	   supported_sectorsizes_show);



static struct attribute *btrfs_supported_static_feature_attrs[] = {

	BTRFS_ATTR_PTR(static_feature, rmdir_subvol),

	BTRFS_ATTR_PTR(static_feature, supported_checksums),

	BTRFS_ATTR_PTR(static_feature, send_stream_version),

	BTRFS_ATTR_PTR(static_feature, supported_rescue_options),

	BTRFS_ATTR_PTR(static_feature, supported_sectorsizes),

	NULL

};