Btrfs: introduce subvol uuids and times

[linux-2.6-block.git] / fs / btrfs / ctree.h

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 8cfde9326dd6d90dff9accfc3f4d92f4d3b44874..d5f6d7458676c7c323ac129330172dd5c29c8c3a 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -709,6 +709,36 @@ struct btrfs_root_item {
        struct btrfs_disk_key drop_progress;
        u8 drop_level;
        u8 level;
+
+       /*
+        * The following fields appear after subvol_uuids+subvol_times
+        * were introduced.
+        */
+
+       /*
+        * This generation number is used to test if the new fields are valid
+        * and up to date while reading the root item. Everytime the root item
+        * is written out, the "generation" field is copied into this field. If
+        * anyone ever mounted the fs with an older kernel, we will have
+        * mismatching generation values here and thus must invalidate the
+        * new fields. See btrfs_update_root and btrfs_find_last_root for
+        * details.
+        * the offset of generation_v2 is also used as the start for the memset
+        * when invalidating the fields.
+        */
+       __le64 generation_v2;
+       u8 uuid[BTRFS_UUID_SIZE];
+       u8 parent_uuid[BTRFS_UUID_SIZE];
+       u8 received_uuid[BTRFS_UUID_SIZE];
+       __le64 ctransid; /* updated when an inode changes */
+       __le64 otransid; /* trans when created */
+       __le64 stransid; /* trans when sent. non-zero for received subvol */
+       __le64 rtransid; /* trans when received. non-zero for received subvol */
+       struct btrfs_timespec ctime;
+       struct btrfs_timespec otime;
+       struct btrfs_timespec stime;
+       struct btrfs_timespec rtime;
+       __le64 reserved[8]; /* for future */
 } __attribute__ ((__packed__));
 
 /*
@@ -1416,6 +1446,8 @@ struct btrfs_root {
        dev_t anon_dev;
 
        int force_cow;
+
+       spinlock_t root_times_lock;
 };
 
 struct btrfs_ioctl_defrag_range_args {
@@ -2189,6 +2221,16 @@ BTRFS_SETGET_STACK_FUNCS(root_used, struct btrfs_root_item, bytes_used, 64);
 BTRFS_SETGET_STACK_FUNCS(root_limit, struct btrfs_root_item, byte_limit, 64);
 BTRFS_SETGET_STACK_FUNCS(root_last_snapshot, struct btrfs_root_item,
                         last_snapshot, 64);
+BTRFS_SETGET_STACK_FUNCS(root_generation_v2, struct btrfs_root_item,
+                        generation_v2, 64);
+BTRFS_SETGET_STACK_FUNCS(root_ctransid, struct btrfs_root_item,
+                        ctransid, 64);
+BTRFS_SETGET_STACK_FUNCS(root_otransid, struct btrfs_root_item,
+                        otransid, 64);
+BTRFS_SETGET_STACK_FUNCS(root_stransid, struct btrfs_root_item,
+                        stransid, 64);
+BTRFS_SETGET_STACK_FUNCS(root_rtransid, struct btrfs_root_item,
+                        rtransid, 64);
 
 static inline bool btrfs_root_readonly(struct btrfs_root *root)
 {
@@ -2822,6 +2864,9 @@ int __must_check btrfs_update_root(struct btrfs_trans_handle *trans,
                                   struct btrfs_root *root,
                                   struct btrfs_key *key,
                                   struct btrfs_root_item *item);
+void btrfs_read_root_item(struct btrfs_root *root,
+                        struct extent_buffer *eb, int slot,
+                        struct btrfs_root_item *item);
 int btrfs_find_last_root(struct btrfs_root *root, u64 objectid, struct
                         btrfs_root_item *item, struct btrfs_key *key);
 int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid);
@@ -2829,6 +2874,8 @@ int btrfs_find_orphan_roots(struct btrfs_root *tree_root);
 void btrfs_set_root_node(struct btrfs_root_item *item,
                         struct extent_buffer *node);
 void btrfs_check_and_init_root_item(struct btrfs_root_item *item);
+void btrfs_update_root_times(struct btrfs_trans_handle *trans,
+                            struct btrfs_root *root);
 
 /* dir-item.c */
 int btrfs_insert_dir_item(struct btrfs_trans_handle *trans,