ext4_get_link(): fix breakage in RCU mode

1) errors from ext4_getblk() should not be propagated to caller
unless we are really sure that we would've gotten the same error
in non-RCU pathwalk.
2) we leak buffer_heads if ext4_getblk() is successful, but bh is
not uptodate.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c
index 75bf1f88843c4ce96c285423228a70ff77c08517..645240cc0229fe4a2eda4499ae4a834fe3bd3a66 100644 (file)
--- a/fs/ext4/symlink.c
+++ b/fs/ext4/symlink.c
@@ -92,10 +92,12 @@ static const char *ext4_get_link(struct dentry *dentry, struct inode *inode,
 
        if (!dentry) {
                bh = ext4_getblk(NULL, inode, 0, EXT4_GET_BLOCKS_CACHED_NOWAIT);
-               if (IS_ERR(bh))
-                       return ERR_CAST(bh);
-               if (!bh || !ext4_buffer_uptodate(bh))
+               if (IS_ERR(bh) || !bh)
                        return ERR_PTR(-ECHILD);
+               if (!ext4_buffer_uptodate(bh)) {
+                       brelse(bh);
+                       return ERR_PTR(-ECHILD);
+               }
        } else {
                bh = ext4_bread(NULL, inode, 0, 0);
                if (IS_ERR(bh))