Deletion of a subvolume by rmdir(2) has become allowed by the
'commit cd2decf640b1 ("btrfs: Allow rmdir(2) to delete an empty
subvolume")'.It is a kind of new feature and this commits add new sysfs entry /sys/fs/btrfs/features/rmdir_subvol to indicate the feature. Since the behavior is independent of feature bits of superblock, new type FEAT_KERNEL is added to struct btrfs_feature_set. Features of FEAT_KERNEL is supposed to be visible only in /sys/fs/features and not in /sys/fs/UUID/features. Signed-off-by: Tomohiro Misono <[email protected]> --- fs/btrfs/ctree.h | 6 ++++++ fs/btrfs/sysfs.c | 36 +++++++++++++++++++++++++++--------- fs/btrfs/sysfs.h | 5 ++++- include/uapi/linux/btrfs.h | 2 ++ 4 files changed, 39 insertions(+), 10 deletions(-) diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 954bfb5054b1..c98355a468a9 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -271,6 +271,12 @@ struct btrfs_super_block { (BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF) #define BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR 0ULL +#define BTRFS_FEATURE_KERNEL_SUPP \ + BTRFS_FEATURE_KERNEL_RMDIR_SUBVOL + +#define BTRFS_FEATURE_KERNEL_SAFE_SET 0ULL +#define BTRFS_FEATURE_KERNEL_SAFE_CLEAR 0ULL + /* * A leaf is full of items. offset and size tell us where to find * the item in the leaf (relative to the start of the data area) diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c index 217d401fe8ae..ce6ba6b204c3 100644 --- a/fs/btrfs/sysfs.c +++ b/fs/btrfs/sysfs.c @@ -30,20 +30,24 @@ static u64 get_features(struct btrfs_fs_info *fs_info, return btrfs_super_compat_flags(disk_super); else if (set == FEAT_COMPAT_RO) return btrfs_super_compat_ro_flags(disk_super); - else + else if (set == FEAT_INCOMPAT) return btrfs_super_incompat_flags(disk_super); + else + return BTRFS_FEATURE_KERNEL_SUPP; } static void set_features(struct btrfs_fs_info *fs_info, enum btrfs_feature_set set, u64 features) { struct btrfs_super_block *disk_super = fs_info->super_copy; + if (set == FEAT_COMPAT) btrfs_set_super_compat_flags(disk_super, features); else if (set == FEAT_COMPAT_RO) btrfs_set_super_compat_ro_flags(disk_super, features); - else + else if (set == FEAT_INCOMPAT) btrfs_set_super_incompat_flags(disk_super, features); + /* Nothing for FEAT_KERNEL for now */ } static int can_modify_feature(struct btrfs_feature_attr *fa) @@ -63,6 +67,10 @@ static int can_modify_feature(struct btrfs_feature_attr *fa) set = BTRFS_FEATURE_INCOMPAT_SAFE_SET; clear = BTRFS_FEATURE_INCOMPAT_SAFE_CLEAR; break; + case FEAT_KERNEL: + set = BTRFS_FEATURE_KERNEL_SAFE_SET; + clear = BTRFS_FEATURE_KERNEL_SAFE_CLEAR; + break; default: pr_warn("btrfs: sysfs: unknown feature set %d\n", fa->feature_set); @@ -110,6 +118,10 @@ static ssize_t btrfs_feature_attr_store(struct kobject *kobj, if (sb_rdonly(fs_info->sb)) return -EROFS; + /* FEAT_KERNEL features cannot be changed at runtime */ + if (fa->feature_set == FEAT_KERNEL) + return -EINVAL; + ret = kstrtoul(skip_spaces(buf), 0, &val); if (ret) return ret; @@ -174,7 +186,10 @@ static umode_t btrfs_feature_visible(struct kobject *kobj, fa = attr_to_btrfs_feature_attr(attr); features = get_features(fs_info, fa->feature_set); - if (can_modify_feature(fa)) + /* Do not show FEAT_KERNEL features in /sys/fs/UUID/features */ + if (fa->feature_set == FEAT_KERNEL) + mode = 0; + else if (can_modify_feature(fa)) mode |= S_IWUSR; else if (!(features & fa->feature_bit)) mode = 0; @@ -194,6 +209,7 @@ BTRFS_FEAT_ATTR_INCOMPAT(raid56, RAID56); BTRFS_FEAT_ATTR_INCOMPAT(skinny_metadata, SKINNY_METADATA); BTRFS_FEAT_ATTR_INCOMPAT(no_holes, NO_HOLES); BTRFS_FEAT_ATTR_COMPAT_RO(free_space_tree, FREE_SPACE_TREE); +BTRFS_FEAT_ATTR_KERNEL(rmdir_subvol, RMDIR_SUBVOL); static struct attribute *btrfs_supported_feature_attrs[] = { BTRFS_FEAT_ATTR_PTR(mixed_backref), @@ -207,6 +223,7 @@ static struct attribute *btrfs_supported_feature_attrs[] = { BTRFS_FEAT_ATTR_PTR(skinny_metadata), BTRFS_FEAT_ATTR_PTR(no_holes), BTRFS_FEAT_ATTR_PTR(free_space_tree), + BTRFS_FEAT_ATTR_PTR(rmdir_subvol), NULL }; @@ -515,10 +532,11 @@ static inline struct btrfs_fs_info *to_fs_info(struct kobject *kobj) #define NUM_FEATURE_BITS 64 #define BTRFS_FEATURE_NAME_MAX 13 -static char btrfs_unknown_feature_names[FEAT_MAX][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX]; -static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX][NUM_FEATURE_BITS]; +/* These are for features related to feature bit and FEAT_KERNEL is excluded */ +static char btrfs_unknown_feature_names[FEAT_MAX-1][NUM_FEATURE_BITS][BTRFS_FEATURE_NAME_MAX]; +static struct btrfs_feature_attr btrfs_feature_attrs[FEAT_MAX-1][NUM_FEATURE_BITS]; -static const u64 supported_feature_masks[FEAT_MAX] = { +static const u64 supported_feature_masks[FEAT_MAX-1] = { [FEAT_COMPAT] = BTRFS_FEATURE_COMPAT_SUPP, [FEAT_COMPAT_RO] = BTRFS_FEATURE_COMPAT_RO_SUPP, [FEAT_INCOMPAT] = BTRFS_FEATURE_INCOMPAT_SUPP, @@ -528,7 +546,7 @@ static int addrm_unknown_feature_attrs(struct btrfs_fs_info *fs_info, bool add) { int set; - for (set = 0; set < FEAT_MAX; set++) { + for (set = 0; set < FEAT_MAX-1; set++) { int i; struct attribute *attrs[2]; struct attribute_group agroup = { @@ -610,7 +628,7 @@ void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info) btrfs_sysfs_rm_device_link(fs_info->fs_devices, NULL); } -const char * const btrfs_feature_set_names[FEAT_MAX] = { +const char * const btrfs_feature_set_names[FEAT_MAX-1] = { [FEAT_COMPAT] = "compat", [FEAT_COMPAT_RO] = "compat_ro", [FEAT_INCOMPAT] = "incompat", @@ -666,7 +684,7 @@ static void init_feature_attrs(void) fa->kobj_attr.attr.name = sfa->kobj_attr.attr.name; } - for (set = 0; set < FEAT_MAX; set++) { + for (set = 0; set < FEAT_MAX-1; set++) { for (i = 0; i < ARRAY_SIZE(btrfs_feature_attrs[set]); i++) { char *name = btrfs_unknown_feature_names[set][i]; fa = &btrfs_feature_attrs[set][i]; diff --git a/fs/btrfs/sysfs.h b/fs/btrfs/sysfs.h index 40716b357c1d..e8547a46ce13 100644 --- a/fs/btrfs/sysfs.h +++ b/fs/btrfs/sysfs.h @@ -12,6 +12,7 @@ enum btrfs_feature_set { FEAT_COMPAT, FEAT_COMPAT_RO, FEAT_INCOMPAT, + FEAT_KERNEL, /* Kernel feature indepenedent of feature bits */ FEAT_MAX }; @@ -57,6 +58,8 @@ static struct btrfs_feature_attr btrfs_attr_features_##_name = { \ BTRFS_FEAT_ATTR(name, FEAT_COMPAT_RO, BTRFS_FEATURE_COMPAT_RO, feature) #define BTRFS_FEAT_ATTR_INCOMPAT(name, feature) \ BTRFS_FEAT_ATTR(name, FEAT_INCOMPAT, BTRFS_FEATURE_INCOMPAT, feature) +#define BTRFS_FEAT_ATTR_KERNEL(name, feature) \ + BTRFS_FEAT_ATTR(name, FEAT_KERNEL, BTRFS_FEATURE_KERNEL, feature) /* convert from attribute */ static inline struct btrfs_feature_attr * @@ -77,7 +80,7 @@ attr_to_btrfs_feature_attr(struct attribute *attr) } char *btrfs_printable_features(enum btrfs_feature_set set, u64 flags); -extern const char * const btrfs_feature_set_names[FEAT_MAX]; +extern const char * const btrfs_feature_set_names[FEAT_MAX-1]; extern struct kobj_type space_info_ktype; extern struct kobj_type btrfs_raid_ktype; int btrfs_sysfs_add_device_link(struct btrfs_fs_devices *fs_devices, diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h index c8d99b9ca550..631061f42745 100644 --- a/include/uapi/linux/btrfs.h +++ b/include/uapi/linux/btrfs.h @@ -270,6 +270,8 @@ struct btrfs_ioctl_fs_info_args { #define BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA (1ULL << 8) #define BTRFS_FEATURE_INCOMPAT_NO_HOLES (1ULL << 9) +#define BTRFS_FEATURE_KERNEL_RMDIR_SUBVOL (1ULL << 0) + struct btrfs_ioctl_feature_flags { __u64 compat_flags; __u64 compat_ro_flags; -- 2.14.3 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
