btrfs: publish per-super features in sysfs - kernel/git/torvalds/linux.git - Linux kernel source tree
- ️Fri Nov 01 2013
This patch publishes information on which features are enabled in the file system on a per-super basis. At this point, it only publishes information on features supported by the file system implementation. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 79be4a187af9e0..832cf62151ffbf 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -28,29 +28,53 @@
#include "transaction.h"
#include "sysfs.h"
-static void btrfs_release_super_kobj(struct kobject *kobj);
-static struct kobj_type btrfs_ktype = {
- .sysfs_ops = &kobj_sysfs_ops,
- .release = btrfs_release_super_kobj,
-};
+static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj);
-static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
+static u64 get_features(struct btrfs_fs_info *fs_info,
+ enum btrfs_feature_set set)
{
- if (kobj->ktype != &btrfs_ktype)
- return NULL;
- return container_of(kobj, struct btrfs_fs_info, super_kobj);
+ struct btrfs_super_block *disk_super = fs_info->super_copy;
+ if (set == FEAT_COMPAT)
+ return btrfs_super_compat_flags(disk_super);
+ else if (set == FEAT_COMPAT_RO)
+ return btrfs_super_compat_ro_flags(disk_super);
+ else
+ return btrfs_super_incompat_flags(disk_super);
}
-static void btrfs_release_super_kobj(struct kobject *kobj)
+static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
+ struct kobj_attribute *a, char *buf)
{
+ int val = 0;
struct btrfs_fs_info *fs_info = to_fs_info(kobj);
- complete(&fs_info->kobj_unregister);
+ if (fs_info) {
+ struct btrfs_feature_attr *fa = to_btrfs_feature_attr(a);
+ u64 features = get_features(fs_info, fa->feature_set);
+ if (features & fa->feature_bit)
+ val = 1;
+ }
+
+ return snprintf(buf, PAGE_SIZE, "%d\n", val);
}
-static ssize_t btrfs_feature_attr_show(struct kobject *kobj,
- struct kobj_attribute *a, char *buf)
+static umode_t btrfs_feature_visible(struct kobject *kobj,
+ struct attribute *attr, int unused)
{
- return snprintf(buf, PAGE_SIZE, "0\n");
+ struct btrfs_fs_info *fs_info = to_fs_info(kobj);
+ umode_t mode = attr->mode;
+
+ if (fs_info) {
+ struct btrfs_feature_attr *fa;
+ u64 features;
+
+ fa = attr_to_btrfs_feature_attr(attr);
+ features = get_features(fs_info, fa->feature_set);
+
+ if (!(features & fa->feature_bit))
+ mode = 0;
+ }
+
+ return mode;
}
BTRFS_FEAT_ATTR_INCOMPAT(mixed_backref, MIXED_BACKREF);
@@ -78,11 +102,27 @@ static struct attribute *btrfs_supported_feature_attrs[] = {
static const struct attribute_group btrfs_feature_attr_group = {
.name = "features",
+ .is_visible = btrfs_feature_visible,
.attrs = btrfs_supported_feature_attrs,
};
-/* /sys/fs/btrfs/ entry */
-static struct kset *btrfs_kset;
+static void btrfs_release_super_kobj(struct kobject *kobj)
+{
+ struct btrfs_fs_info *fs_info = to_fs_info(kobj);
+ complete(&fs_info->kobj_unregister);
+}
+
+static struct kobj_type btrfs_ktype = {
+ .sysfs_ops = &kobj_sysfs_ops,
+ .release = btrfs_release_super_kobj,
+};
+
+static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj)
+{
+ if (kobj->ktype != &btrfs_ktype)
+ return NULL;
+ return container_of(kobj, struct btrfs_fs_info, super_kobj);
+}
void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
{
@@ -91,13 +131,22 @@ void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info)
wait_for_completion(&fs_info->kobj_unregister);
}
+/* /sys/fs/btrfs/ entry */
+static struct kset *btrfs_kset;
+
int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info)
{
int error;
init_completion(&fs_info->kobj_unregister);
+ fs_info->super_kobj.kset = btrfs_kset;
error = kobject_init_and_add(&fs_info->super_kobj, &btrfs_ktype, NULL,
"%pU", fs_info->fsid);
+
+ error = sysfs_create_group(&fs_info->super_kobj,
+ &btrfs_feature_attr_group);
+ if (error)
+ btrfs_sysfs_remove_one(fs_info);
return error;
}