btrfs: sysfs: export supported checksums
Export supported checksum algorithms via sysfs.
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
---
Changes to v2:
- Prevent possible overflow of sysfs attribute
Changes to v1:
- Removed btrfs_checksums_store() function (Nik)
- Renamed sysfs file to supported_checksums
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index f6d3c80..cae9c99 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -246,6 +246,24 @@
return mode;
}
+static ssize_t btrfs_supported_checksums_show(struct kobject *kobj,
+ struct kobj_attribute *a,
+ char *buf)
+{
+ ssize_t ret = 0;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(btrfs_csums); i++) {
+ ret += snprintf(buf + ret, PAGE_SIZE - ret, "%s%s",
+ (i == 0 ? "" : ", "),
+ btrfs_csums[i].name);
+
+ }
+
+ ret += snprintf(buf + ret, PAGE_SIZE - ret, "\n");
+ return ret;
+}
+
BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
BTRFS_FEAT_ATTR_INCOMPAT(default_subvol, DEFAULT_SUBVOL);
BTRFS_FEAT_ATTR_INCOMPAT(mixed_groups, MIXED_GROUPS);
@@ -259,6 +277,14 @@
BTRFS_FEAT_ATTR_INCOMPAT(metadata_uuid, METADATA_UUID);
BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE);
+static struct btrfs_feature_attr btrfs_attr_features_checksums_name = {
+ .kobj_attr = __INIT_KOBJ_ATTR(supported_checksums, S_IRUGO,
+ btrfs_supported_checksums_show,
+ NULL),
+ .feature_set = FEAT_INCOMPAT,
+ .feature_bit = 0,
+};
+
static struct attribute *btrfs_supported_feature_attrs[] = {
BTRFS_FEAT_ATTR_PTR(mixed_backref),
BTRFS_FEAT_ATTR_PTR(default_subvol),
@@ -272,6 +298,9 @@
BTRFS_FEAT_ATTR_PTR(no_holes),
BTRFS_FEAT_ATTR_PTR(metadata_uuid),
BTRFS_FEAT_ATTR_PTR(free_space_tree),
+
+ &btrfs_attr_features_checksums_name.kobj_attr.attr,
+
NULL
};
