[PATCH 1/5] fs/gfs2: test for IS_ERR rather than 0

[PATCH 1/5] fs/gfs2: test for IS_ERR rather than 0

[Julia Lawall]

From: Julia Lawall <julia@diku.dk>

The function gfs2_inode_lookup always returns either a valid pointer or a
value made with ERR_PTR, so its result should be tested with IS_ERR, not
with a test for 0.


The problem was found using the following semantic match.
(http://www.emn.fr/x-info/coccinelle/)

//<smpl>
@a@
expression E, E1;
statement S,S1;
position p;
@@

E = gfs2_inode_lookup(...)
... when != E = E1
if@p (E) S else S1

@n@
position a.p;
expression E,E1;
statement S,S1;
@@

E = NULL
... when != E = E1
if@p (E) S else S1

@depends on !n@
expression E;
statement S,S1;
position a.p;
@@

* if@p (E)
  S else S1
//</smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
---
 fs/gfs2/ops_export.c |    2 --
 1 file changed, 2 deletions(-)

diff -u -p a/fs/gfs2/ops_export.c b/fs/gfs2/ops_export.c
--- a/fs/gfs2/ops_export.c	2008-03-12 14:13:14.000000000 +0100
+++ b/fs/gfs2/ops_export.c	2008-03-24 16:04:41.000000000 +0100
@@ -204,8 +204,6 @@ static struct dentry *gfs2_get_dentry(st
 	inode = gfs2_inode_lookup(sb, DT_UNKNOWN,
 					inum->no_addr,
 					0, 0);
-	if (!inode)
-		goto fail;
 	if (IS_ERR(inode)) {
 		error = PTR_ERR(inode);
 		goto fail;

Re: [PATCH 1/5] fs/gfs2: test for IS_ERR rather than 0

[Steven Whitehouse]

Hi,

On Mon, 2008-03-24 at 19:08 +0100, Julia Lawall wrote:
> From: Julia Lawall <julia@diku.dk>
> 
> The function gfs2_inode_lookup always returns either a valid pointer or a
> value made with ERR_PTR, so its result should be tested with IS_ERR, not
> with a test for 0.
> 
Sorry for the delay - I've just got back from holiday. Its now in the
GFS2 -nmw git tree. Also I updated the tree to the latest Linus git tree
at the same time. Thanks,

Steve.