Btrfs: add the tree history log to btrfs-progs

This also adds btrfs-debug-tree -R to print the history

Signed-off-by: Chris Mason <chris.mason@oracle.com>

2 files changed, 139 insertions, 1 deletions

diff --git a/ctree.h b/ctree.h
index b1a87c8..54748c8 100644
--- a/ctree.h
+++ b/ctree.h
@@ -312,6 +312,47 @@ 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
  */
@@ -357,6 +398,7 @@ 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__));
 
 /*
@@ -1537,6 +1579,55 @@ BTRFS_SETGET_STACK_FUNCS(root_last_snapshot, struct btrfs_root_item,
 			 last_snapshot, 64);
 
 
+/* 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);
diff --git a/debug-tree.c b/debug-tree.c
index 91e0064..2aeabfd 100644
--- a/debug-tree.c
+++ b/debug-tree.c
@@ -62,6 +62,45 @@ static void print_extents(struct btrfs_root *root, struct extent_buffer *eb)
 	}
 }
 
+static void print_old_roots(struct btrfs_super_block *super)
+{
+	struct btrfs_root_backup *backup;
+	int i;
+
+	for (i = 0; i < BTRFS_NUM_BACKUP_ROOTS; i++) {
+		backup = super->super_roots + i;
+		printf("btrfs root backup slot %d\n", i);
+		printf("\ttree root gen %llu block %llu\n",
+		       (unsigned long long)btrfs_backup_tree_root_gen(backup),
+		       (unsigned long long)btrfs_backup_tree_root(backup));
+
+		printf("\t\textent root gen %llu block %llu\n",
+		       (unsigned long long)btrfs_backup_extent_root_gen(backup),
+		       (unsigned long long)btrfs_backup_extent_root(backup));
+
+		printf("\t\tchunk root gen %llu block %llu\n",
+		       (unsigned long long)btrfs_backup_chunk_root_gen(backup),
+		       (unsigned long long)btrfs_backup_chunk_root(backup));
+
+		printf("\t\tdevice root gen %llu block %llu\n",
+		       (unsigned long long)btrfs_backup_dev_root_gen(backup),
+		       (unsigned long long)btrfs_backup_dev_root(backup));
+
+		printf("\t\tcsum root gen %llu block %llu\n",
+		       (unsigned long long)btrfs_backup_csum_root_gen(backup),
+		       (unsigned long long)btrfs_backup_csum_root(backup));
+
+		printf("\t\tfs root gen %llu block %llu\n",
+		       (unsigned long long)btrfs_backup_fs_root_gen(backup),
+		       (unsigned long long)btrfs_backup_fs_root(backup));
+
+		printf("\t\t%llu used %llu total %llu devices\n",
+		       (unsigned long long)btrfs_backup_bytes_used(backup),
+		       (unsigned long long)btrfs_backup_total_bytes(backup),
+		       (unsigned long long)btrfs_backup_num_devices(backup));
+	}
+}
+
 int main(int ac, char **av)
 {
 	struct btrfs_root *root;
@@ -77,6 +116,7 @@ int main(int ac, char **av)
 	int extent_only = 0;
 	int device_only = 0;
 	int roots_only = 0;
+	int root_backups = 0;
 	u64 block_only = 0;
 	struct btrfs_root *tree_root_scan;
 
@@ -84,7 +124,7 @@ int main(int ac, char **av)
 
 	while(1) {
 		int c;
-		c = getopt(ac, av, "deb:r");
+		c = getopt(ac, av, "deb:rR");
 		if (c < 0)
 			break;
 		switch(c) {
@@ -97,6 +137,10 @@ int main(int ac, char **av)
 			case 'r':
 				roots_only = 1;
 				break;
+			case 'R':
+				roots_only = 1;
+				root_backups = 1;
+				break;
 			case 'b':
 				block_only = atoll(optarg);
 				break;
@@ -289,6 +333,9 @@ again:
 	if (extent_only || device_only)
 		return 0;
 
+	if (root_backups)
+		print_old_roots(&root->fs_info->super_copy);
+
 	printf("total bytes %llu\n",
 	       (unsigned long long)btrfs_super_total_bytes(&root->fs_info->super_copy));
 	printf("bytes used %llu\n",