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authorDavid Sterba <dsterba@suse.cz>2014-04-15 18:41:44 +0400
committerChris Mason <clm@fb.com>2014-06-10 04:20:31 +0400
commit521e0546c970c3d845076f243828fa7abd71edfc (patch)
treee203f19e76c97629173c097e051946e2aeb6ce4a /fs/btrfs/ctree.h
parent944a4515b27302ac42d5964b7400c72f4d692782 (diff)
downloadlinux-521e0546c970c3d845076f243828fa7abd71edfc.tar.xz
btrfs: protect snapshots from deleting during send
The patch "Btrfs: fix protection between send and root deletion" (18f687d538449373c37c) does not actually prevent to delete the snapshot and just takes care during background cleaning, but this seems rather user unfriendly, this patch implements the idea presented in http://www.spinics.net/lists/linux-btrfs/msg30813.html - add an internal root_item flag to denote a dead root - check if the send_in_progress is set and refuse to delete, otherwise set the flag and proceed - check the flag in send similar to the btrfs_root_readonly checks, for all involved roots The root lookup in send via btrfs_read_fs_root_no_name will check if the root is really dead or not. If it is, ENOENT, aborted send. If it's alive, it's protected by send_in_progress, send can continue. CC: Miao Xie <miaox@cn.fujitsu.com> CC: Wang Shilong <wangsl.fnst@cn.fujitsu.com> Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'fs/btrfs/ctree.h')
-rw-r--r--fs/btrfs/ctree.h11
1 files changed, 11 insertions, 0 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index e6f899dc5e47..f4a439e1a43f 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -756,6 +756,12 @@ struct btrfs_dir_item {
#define BTRFS_ROOT_SUBVOL_RDONLY (1ULL << 0)
+/*
+ * Internal in-memory flag that a subvolume has been marked for deletion but
+ * still visible as a directory
+ */
+#define BTRFS_ROOT_SUBVOL_DEAD (1ULL << 48)
+
struct btrfs_root_item {
struct btrfs_inode_item inode;
__le64 generation;
@@ -2791,6 +2797,11 @@ static inline bool btrfs_root_readonly(struct btrfs_root *root)
return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_RDONLY)) != 0;
}
+static inline bool btrfs_root_dead(struct btrfs_root *root)
+{
+ return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_DEAD)) != 0;
+}
+
/* struct btrfs_root_backup */
BTRFS_SETGET_STACK_FUNCS(backup_tree_root, struct btrfs_root_backup,
tree_root, 64);