Re: 2.6.0-test4-mm3.1 oops with ext3 extended attributes on R/O filesystem

[Andrew Morton <akpm@osdl.org>]

Valdis.Kletnieks@vt.edu wrote:
>
> Working on installing SELINUX, and I get to the part where all the file labels
>  get added.  Unfortunately, I had some file systems mounted R/O (intentionally,
>  forgot to mount them R/W for this).  The ext3 code upchucked while trying
>  to set extended attributes on the filesystem it couldn't write to.

Thanks.   It's a very straightforward bug; I'll fix it with the below patch.

A wider question is whether we should have got this far into the filesystem
code if the fs is mounted read-only.  A check right up at the VFS
setxattr() level might make sense.

Regardless of that, this fix is needed because journal_start() could fail
for other reasons.


diff -puN fs/ext3/xattr.c~ext3-xattr-oops-fix fs/ext3/xattr.c
--- 25/fs/ext3/xattr.c~ext3-xattr-oops-fix	2003-08-30 21:41:24.000000000 -0700
+++ 25-akpm/fs/ext3/xattr.c	2003-08-30 21:42:41.000000000 -0700
@@ -873,17 +873,22 @@ ext3_xattr_set(struct inode *inode, int 
 	       const void *value, size_t value_len, int flags)
 {
 	handle_t *handle;
-	int error, error2;
+	int error;
 
 	handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS);
-	if (IS_ERR(handle))
+	if (IS_ERR(handle)) {
 		error = PTR_ERR(handle);
-	else
+	} else {
+		int error2;
+
 		error = ext3_xattr_set_handle(handle, inode, name_index, name,
 					      value, value_len, flags);
-	error2 = ext3_journal_stop(handle);
+		error2 = ext3_journal_stop(handle);
+		if (error == 0)
+			error = error2;
+	}
 
-	return error ? error : error2;
+	return error;
 }
 
 /*

_