Btrfs: Add the ability to find and remove dead roots after a crash.

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

1 files changed, 30 insertions, 14 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 865a284aa06c..d7615e1578cc 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -326,8 +326,8 @@ static int find_and_setup_root(int blocksize,
         return 0;
 }
 
-struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
-                                      struct btrfs_key *location)
+struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_fs_info *fs_info,
+                                               struct btrfs_key *location)
 {
         struct btrfs_root *root;
         struct btrfs_root *tree_root = fs_info->tree_root;
@@ -336,11 +336,7 @@ struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
         u64 highest_inode;
         int ret = 0;
 
-        root = radix_tree_lookup(&fs_info->fs_roots_radix,
-                                 (unsigned long)location->objectid);
-        if (root)
-                return root;
-        root = kmalloc(sizeof(*root), GFP_NOFS);
+        root = kzalloc(sizeof(*root), GFP_NOFS);
         if (!root)
                 return ERR_PTR(-ENOMEM);
         if (location->offset == (u64)-1) {
@@ -383,6 +379,28 @@ out:
         BUG_ON(!root->node);
 insert:
         root->ref_cows = 1;
+        ret = btrfs_find_highest_inode(root, &highest_inode);
+        if (ret == 0) {
+                root->highest_inode = highest_inode;
+                root->last_inode_alloc = highest_inode;
+        }
+        return root;
+}
+
+struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
+                                      struct btrfs_key *location)
+{
+        struct btrfs_root *root;
+        int ret;
+
+        root = radix_tree_lookup(&fs_info->fs_roots_radix,
+                                 (unsigned long)location->objectid);
+        if (root)
+                return root;
+
+        root = btrfs_read_fs_root_no_radix(fs_info, location);
+        if (IS_ERR(root))
+                return root;
         ret = radix_tree_insert(&fs_info->fs_roots_radix,
                                 (unsigned long)root->root_key.objectid,
                                 root);
@@ -391,11 +409,6 @@ insert:
                 kfree(root);
                 return ERR_PTR(ret);
         }
-        ret = btrfs_find_highest_inode(root, &highest_inode);
-        if (ret == 0) {
-                root->highest_inode = highest_inode;
-                root->last_inode_alloc = highest_inode;
-        }
         return root;
 }
 
@@ -489,6 +502,9 @@ struct btrfs_root *open_ctree(struct super_block *sb)
         btrfs_read_block_groups(extent_root);
 
         fs_info->generation = btrfs_super_generation(disk_super) + 1;
+        ret = btrfs_find_dead_roots(tree_root);
+        if (ret)
+                goto fail_tree_root;
         mutex_unlock(&fs_info->fs_mutex);
         return tree_root;
 
@@ -538,7 +554,7 @@ int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
         return 0;
 }
 
-static int free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
+int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
 {
         radix_tree_delete(&fs_info->fs_roots_radix,
                           (unsigned long)root->root_key.objectid);
@@ -565,7 +581,7 @@ static int del_fs_roots(struct btrfs_fs_info *fs_info)
                 if (!ret)
                         break;
                 for (i = 0; i < ret; i++)
-                        free_fs_root(fs_info, gang[i]);
+                        btrfs_free_fs_root(fs_info, gang[i]);
         }
         return 0;
 }