Btrfs: fix inode cache writeout

The code to fix stalls during free spache cache IO wasn't using
the correct root when waiting on the IO for inode caches.  This
is only a problem when the inode cache is enabled with

mount -o inode_cache

This fixes the inode cache writeout to preserve any error values and
makes sure not to override the root when inode cache writeout is done.

Reported-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 253cb74b0e27..d773f229d14d 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -1149,7 +1149,8 @@ int btrfs_wait_cache_io(struct btrfs_root *root,
         if (!inode)
                 return 0;
 
-        root = root->fs_info->tree_root;
+        if (block_group)
+                root = root->fs_info->tree_root;
 
         /* Flush the dirty pages in the cache file. */
         ret = flush_dirty_cache(inode);
@@ -3463,9 +3464,12 @@ int btrfs_write_out_ino_cache(struct btrfs_root *root,
         if (!btrfs_test_opt(root, INODE_MAP_CACHE))
                 return 0;
 
+        memset(&io_ctl, 0, sizeof(io_ctl));
         ret = __btrfs_write_out_cache(root, inode, ctl, NULL, &io_ctl,
-                                      trans, path, 0) ||
-                btrfs_wait_cache_io(root, trans, NULL, &io_ctl, path, 0);
+                                      trans, path, 0);
+        if (!ret)
+                ret = btrfs_wait_cache_io(root, trans, NULL, &io_ctl, path, 0);
+
         if (ret) {
                 btrfs_delalloc_release_metadata(inode, inode->i_size);
 #ifdef DEBUG