Btrfs: Add root tree pointer transaction ids

This patch adds transaction IDs to root tree pointers.
Transaction IDs in tree pointers are compared with the
generation numbers in block headers when reading root
blocks of trees. This can detect some types of IO errors.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>

1 files changed, 14 insertions, 7 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index d1137d7ea8d4..94b4e50f6b2c 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -832,6 +832,7 @@ static int find_and_setup_root(struct btrfs_root *tree_root,
 {
         int ret;
         u32 blocksize;
+        u64 generation;
 
         __setup_root(tree_root->nodesize, tree_root->leafsize,
                      tree_root->sectorsize, tree_root->stripesize,
@@ -840,9 +841,10 @@ static int find_and_setup_root(struct btrfs_root *tree_root,
                                    &root->root_item, &root->root_key);
         BUG_ON(ret);
 
+        generation = btrfs_root_generation(&root->root_item);
         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
-                                     blocksize, 0);
+                                     blocksize, generation);
         BUG_ON(!root->node);
         return 0;
 }
@@ -929,6 +931,7 @@ struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
         struct btrfs_path *path;
         struct extent_buffer *l;
         u64 highest_inode;
+        u64 generation;
         u32 blocksize;
         int ret = 0;
 
@@ -970,9 +973,10 @@ out:
                 kfree(root);
                 return ERR_PTR(ret);
         }
+        generation = btrfs_root_generation(&root->root_item);
         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
-                                     blocksize, 0);
+                                     blocksize, generation);
         BUG_ON(!root->node);
 insert:
         if (location->objectid != BTRFS_TREE_LOG_OBJECTID) {
@@ -1357,6 +1361,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         u32 leafsize;
         u32 blocksize;
         u32 stripesize;
+        u64 generation;
         struct buffer_head *bh;
         struct btrfs_root *extent_root = kzalloc(sizeof(struct btrfs_root),
                                                  GFP_NOFS);
@@ -1596,13 +1601,14 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 
         blocksize = btrfs_level_size(tree_root,
                                      btrfs_super_chunk_root_level(disk_super));
+        generation = btrfs_super_chunk_root_generation(disk_super);
 
         __setup_root(nodesize, leafsize, sectorsize, stripesize,
                      chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
 
         chunk_root->node = read_tree_block(chunk_root,
                                            btrfs_super_chunk_root(disk_super),
-                                           blocksize, 0);
+                                           blocksize, generation);
         BUG_ON(!chunk_root->node);
 
         read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
@@ -1618,11 +1624,11 @@ struct btrfs_root *open_ctree(struct super_block *sb,
 
         blocksize = btrfs_level_size(tree_root,
                                      btrfs_super_root_level(disk_super));
-
+        generation = btrfs_super_generation(disk_super);
 
         tree_root->node = read_tree_block(tree_root,
                                           btrfs_super_root(disk_super),
-                                          blocksize, 0);
+                                          blocksize, generation);
         if (!tree_root->node)
                 goto fail_sb_buffer;
 
@@ -1672,15 +1678,16 @@ struct btrfs_root *open_ctree(struct super_block *sb,
                              log_tree_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
 
                 log_tree_root->node = read_tree_block(tree_root, bytenr,
-                                                      blocksize, 0);
+                                                      blocksize,
+                                                      generation + 1);
                 ret = btrfs_recover_log_trees(log_tree_root);
                 BUG_ON(ret);
         }
+        fs_info->last_trans_committed = btrfs_super_generation(disk_super);
 
         ret = btrfs_cleanup_reloc_trees(tree_root);
         BUG_ON(ret);
 
-        fs_info->last_trans_committed = btrfs_super_generation(disk_super);
         return tree_root;
 
 fail_cleaner: