From: Akria Fujita Date: Sat, 2 Feb 2013 01:52:46 +0000 (-0500) Subject: ext4: fix smatch warning in move_extent.c's mext_replace_branches() X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=87e698734b9e618276c797092ccdd91da292d10e;p=linux-beck.git ext4: fix smatch warning in move_extent.c's mext_replace_branches() Commit 2147b1a6a48 resulted in a new smatch warning: > fs/ext4/move_extent.c:693 mext_replace_branches() > warn: variable dereferenced before check 'dext' (see line 683) Fix this by adding a check to make sure dext is non-NULL before we derefrence it. Signed-off-by: Akria Fujita [ modified by tytso to make sure an ext4_error is called ] Signed-off-by: "Theodore Ts'o" --- diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c index d9cc5ee42f53..e4cdb5188f34 100644 --- a/fs/ext4/move_extent.c +++ b/fs/ext4/move_extent.c @@ -681,6 +681,8 @@ mext_replace_branches(handle_t *handle, struct inode *orig_inode, depth = ext_depth(donor_inode); dext = donor_path[depth].p_ext; + if (unlikely(!dext)) + goto missing_donor_extent; tmp_dext = *dext; *err = mext_calc_swap_extents(&tmp_dext, &tmp_oext, orig_off, @@ -691,7 +693,8 @@ mext_replace_branches(handle_t *handle, struct inode *orig_inode, /* Loop for the donor extents */ while (1) { /* The extent for donor must be found. */ - if (!dext) { + if (unlikely(!dext)) { + missing_donor_extent: EXT4_ERROR_INODE(donor_inode, "The extent for donor must be found"); *err = -EIO;