[PATCH 3/4] btrfs: sysfs: introduce helper for syncing bits with sysfs files
From: David Sterba <dsterba@suse.com>
Date: 2016-01-21 18:32:14
Subsystem:
btrfs file system, filesystems (vfs and infrastructure), the rest · Maintainers:
Chris Mason, David Sterba, Alexander Viro, Christian Brauner, Linus Torvalds
The files under /sys/fs/UUID/features get out of sync with the actual incompat bits set for the filesystem if they change after mount. We're going to sync them and need a helper to do that. Signed-off-by: David Sterba <dsterba@suse.com> --- fs/btrfs/sysfs.c | 30 ++++++++++++++++++++++++++++++ fs/btrfs/sysfs.h | 3 +++ 2 files changed, 33 insertions(+)
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 906f7ed6fc80..6986886243bf 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c@@ -782,6 +782,36 @@ int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info) return error; } + +/* + * Change per-fs features in /sys/fs/btrfs/UUID/features to match current + * values in superblock. Call after any changes to incompat/compat_ro flags + */ +void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info, + u64 bit, enum btrfs_feature_set set) +{ + struct btrfs_fs_devices *fs_devs; + struct kobject *fsid_kobj; + u64 features; + int ret; + + if (!fs_info) + return; + + features = get_features(fs_info, set); + ASSERT(bit & supported_feature_masks[set]); + + fs_devs = fs_info->fs_devices; + fsid_kobj = &fs_devs->fsid_kobj; + + /* + * FIXME: this is too heavy to update just one value, ideally we'd like + * to use sysfs_update_group but some refactoring is needed first. + */ + sysfs_remove_group(fsid_kobj, &btrfs_feature_attr_group); + ret = sysfs_create_group(fsid_kobj, &btrfs_feature_attr_group); +} + static int btrfs_init_debugfs(void) { #ifdef CONFIG_DEBUG_FS
diff --git a/fs/btrfs/sysfs.h b/fs/btrfs/sysfs.h
index 72408e2c4ea8..d7da1a4c2f6c 100644
--- a/fs/btrfs/sysfs.h
+++ b/fs/btrfs/sysfs.h@@ -90,4 +90,7 @@ int btrfs_sysfs_add_fsid(struct btrfs_fs_devices *fs_devs, struct kobject *parent); int btrfs_sysfs_add_device(struct btrfs_fs_devices *fs_devs); void btrfs_sysfs_remove_fsid(struct btrfs_fs_devices *fs_devs); +void btrfs_sysfs_feature_update(struct btrfs_fs_info *fs_info, + u64 bit, enum btrfs_feature_set set); + #endif /* _BTRFS_SYSFS_H_ */
--
2.6.3