btrfs: publish supported featured in sysfs

This patch adds the ability to publish supported features to sysfs under
/sys/fs/btrfs/features.

The files are module-wide and export which features the kernel supports.

The content, for now, is just "0\n".

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <clm@fb.com>
This commit is contained in:
Jeff Mahoney 2013-11-01 13:06:57 -04:00 committed by Chris Mason
parent 29dfe2dc0e
commit 079b72bca3
2 changed files with 87 additions and 0 deletions

View file

@ -26,20 +26,64 @@
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "sysfs.h"
static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
struct kobj_attribute *a, char *buf)
{
return snprintf(buf, PAGE_SIZE, "0\n");
}
BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
BTRFS_FEAT_ATTR_INCOMPAT(compress_lzo, COMPRESS_LZO);
BTRFS_FEAT_ATTR_INCOMPAT(compress_lzov2, COMPRESS_LZOv2);
BTRFS_FEAT_ATTR_INCOMPAT(big_metadata, BIG_METADATA);
BTRFS_FEAT_ATTR_INCOMPAT(extended_iref, EXTENDED_IREF);
BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56);
BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA);
static struct attribute *btrfs_supported_feature_attrs[] = {
BTRFS_FEAT_ATTR_PTR(mixed_backref),
BTRFS_FEAT_ATTR_PTR(default_subvol),
BTRFS_FEAT_ATTR_PTR(mixed_groups),
BTRFS_FEAT_ATTR_PTR(compress_lzo),
BTRFS_FEAT_ATTR_PTR(compress_lzov2),
BTRFS_FEAT_ATTR_PTR(big_metadata),
BTRFS_FEAT_ATTR_PTR(extended_iref),
BTRFS_FEAT_ATTR_PTR(raid56),
BTRFS_FEAT_ATTR_PTR(skinny_metadata),
NULL
};
static const struct attribute_group btrfs_feature_attr_group = {
.name = "features",
.attrs = btrfs_supported_feature_attrs,
};
/* /sys/fs/btrfs/ entry */
static struct kset *btrfs_kset;
int btrfs_init_sysfs(void)
{
int ret;
btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
if (!btrfs_kset)
return -ENOMEM;
ret = sysfs_create_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
if (ret) {
kset_unregister(btrfs_kset);
return ret;
}
return 0;
}
void btrfs_exit_sysfs(void)
{
sysfs_remove_group(&btrfs_kset->kobj, &btrfs_feature_attr_group);
kset_unregister(btrfs_kset);
}