Btrfs: fix all callers of read_tree_block

We kept leaking extent buffers when mounting a broken file system and it turns
out it's because not everybody uses read_tree_block properly.  You need to check
and make sure the extent_buffer is uptodate before you use it.  This patch fixes
everybody who calls read_tree_block directly to make sure they check that it is
uptodate and free it and return an error if it is not.  With this we no longer
leak EB's when things go horribly wrong.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>

1 files changed, 16 insertions, 5 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 566d99b51bef..2bc34408872d 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1281,7 +1281,8 @@ get_old_root(struct btrfs_root *root, u64 time_seq)
                 free_extent_buffer(eb_root);
                 blocksize = btrfs_level_size(root, old_root->level);
                 old = read_tree_block(root, logical, blocksize, 0);
-                if (!old) {
+                if (!old || !extent_buffer_uptodate(old)) {
+                        free_extent_buffer(old);
                         pr_warn("btrfs: failed to read tree block %llu from get_old_root\n",
                                 logical);
                         WARN_ON(1);
@@ -1526,8 +1527,10 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
                         if (!cur) {
                                 cur = read_tree_block(root, blocknr,
                                                          blocksize, gen);
-                                if (!cur)
+                                if (!cur || !extent_buffer_uptodate(cur)) {
+                                        free_extent_buffer(cur);
                                         return -EIO;
+                                }
                         } else if (!uptodate) {
                                 err = btrfs_read_buffer(cur, gen);
                                 if (err) {
@@ -1692,6 +1695,8 @@ static noinline struct extent_buffer *read_node_slot(struct btrfs_root *root,
                                    struct extent_buffer *parent, int slot)
 {
         int level = btrfs_header_level(parent);
+        struct extent_buffer *eb;
+
         if (slot < 0)
                 return NULL;
         if (slot >= btrfs_header_nritems(parent))
@@ -1699,9 +1704,15 @@ static noinline struct extent_buffer *read_node_slot(struct btrfs_root *root,
 
         BUG_ON(level == 0);
 
-        return read_tree_block(root, btrfs_node_blockptr(parent, slot),
-                       btrfs_level_size(root, level - 1),
-                       btrfs_node_ptr_generation(parent, slot));
+        eb = read_tree_block(root, btrfs_node_blockptr(parent, slot),
+                             btrfs_level_size(root, level - 1),
+                             btrfs_node_ptr_generation(parent, slot));
+        if (eb && !extent_buffer_uptodate(eb)) {
+                free_extent_buffer(eb);
+                eb = NULL;
+        }
+
+        return eb;
 }
 
 /*