1 files changed, 95 insertions, 0 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 5181c53c1124..78f43d1102a0 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -361,6 +361,47 @@ struct btrfs_header {
 #define BTRFS_LABEL_SIZE 256
 
 /*
+ * just in case we somehow lose the roots and are not able to mount,
+ * we store an array of the roots from previous transactions
+ * in the super.
+ */
+#define BTRFS_NUM_BACKUP_ROOTS 4
+struct btrfs_root_backup {
+        __le64 tree_root;
+        __le64 tree_root_gen;
+
+        __le64 chunk_root;
+        __le64 chunk_root_gen;
+
+        __le64 extent_root;
+        __le64 extent_root_gen;
+
+        __le64 fs_root;
+        __le64 fs_root_gen;
+
+        __le64 dev_root;
+        __le64 dev_root_gen;
+
+        __le64 csum_root;
+        __le64 csum_root_gen;
+
+        __le64 total_bytes;
+        __le64 bytes_used;
+        __le64 num_devices;
+        /* future */
+        __le64 unsed_64[4];
+
+        u8 tree_root_level;
+        u8 chunk_root_level;
+        u8 extent_root_level;
+        u8 fs_root_level;
+        u8 dev_root_level;
+        u8 csum_root_level;
+        /* future and to align */
+        u8 unused_8[10];
+} __attribute__ ((__packed__));
+
+/*
  * the super block basically lists the main trees of the FS
  * it currently lacks any block count etc etc
  */
@@ -406,6 +447,7 @@ struct btrfs_super_block {
         /* future expansion */
         __le64 reserved[31];
         u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE];
+        struct btrfs_root_backup super_roots[BTRFS_NUM_BACKUP_ROOTS];
 } __attribute__ ((__packed__));
 
 /*
@@ -1113,6 +1155,9 @@ struct btrfs_fs_info {
         u64 fs_state;
 
         struct btrfs_delayed_root *delayed_root;
+
+        /* next backup root to be overwritten */
+        int backup_root_index;
 };
 
 /*
@@ -1357,6 +1402,7 @@ struct btrfs_ioctl_defrag_range_args {
 #define BTRFS_MOUNT_ENOSPC_DEBUG         (1 << 15)
 #define BTRFS_MOUNT_AUTO_DEFRAG         (1 << 16)
 #define BTRFS_MOUNT_INODE_MAP_CACHE     (1 << 17)
+#define BTRFS_MOUNT_RECOVERY            (1 << 18)
 
 #define btrfs_clear_opt(o, opt)         ((o) &= ~BTRFS_MOUNT_##opt)
 #define btrfs_set_opt(o, opt)           ((o) |= BTRFS_MOUNT_##opt)
@@ -1972,6 +2018,55 @@ static inline bool btrfs_root_readonly(struct btrfs_root *root)
         return root->root_item.flags & BTRFS_ROOT_SUBVOL_RDONLY;
 }
 
+/* struct btrfs_root_backup */
+BTRFS_SETGET_STACK_FUNCS(backup_tree_root, struct btrfs_root_backup,
+                   tree_root, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_tree_root_gen, struct btrfs_root_backup,
+                   tree_root_gen, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_tree_root_level, struct btrfs_root_backup,
+                   tree_root_level, 8);
+
+BTRFS_SETGET_STACK_FUNCS(backup_chunk_root, struct btrfs_root_backup,
+                   chunk_root, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_chunk_root_gen, struct btrfs_root_backup,
+                   chunk_root_gen, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_chunk_root_level, struct btrfs_root_backup,
+                   chunk_root_level, 8);
+
+BTRFS_SETGET_STACK_FUNCS(backup_extent_root, struct btrfs_root_backup,
+                   extent_root, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_extent_root_gen, struct btrfs_root_backup,
+                   extent_root_gen, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_extent_root_level, struct btrfs_root_backup,
+                   extent_root_level, 8);
+
+BTRFS_SETGET_STACK_FUNCS(backup_fs_root, struct btrfs_root_backup,
+                   fs_root, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_fs_root_gen, struct btrfs_root_backup,
+                   fs_root_gen, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_fs_root_level, struct btrfs_root_backup,
+                   fs_root_level, 8);
+
+BTRFS_SETGET_STACK_FUNCS(backup_dev_root, struct btrfs_root_backup,
+                   dev_root, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_dev_root_gen, struct btrfs_root_backup,
+                   dev_root_gen, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_dev_root_level, struct btrfs_root_backup,
+                   dev_root_level, 8);
+
+BTRFS_SETGET_STACK_FUNCS(backup_csum_root, struct btrfs_root_backup,
+                   csum_root, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_csum_root_gen, struct btrfs_root_backup,
+                   csum_root_gen, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_csum_root_level, struct btrfs_root_backup,
+                   csum_root_level, 8);
+BTRFS_SETGET_STACK_FUNCS(backup_total_bytes, struct btrfs_root_backup,
+                   total_bytes, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_bytes_used, struct btrfs_root_backup,
+                   bytes_used, 64);
+BTRFS_SETGET_STACK_FUNCS(backup_num_devices, struct btrfs_root_backup,
+                   num_devices, 64);
+
 /* struct btrfs_super_block */
 
 BTRFS_SETGET_STACK_FUNCS(super_bytenr, struct btrfs_super_block, bytenr, 64);