commit: 3798f47aa276b332c30da499cb4df4577e2f8872 From: Sachin Prabhu <[email protected]> Date: Mon, 5 Nov 2012 11:39:32 +0000 Subject: cifs: Do not lookup hashed negative dentry in cifs_atomic_open
We do not need to lookup a hashed negative directory since we have already revalidated it before and have found it to be fine. This also prevents a crash in cifs_lookup() when it attempts to rehash the already hashed negative lookup dentry. The patch has been tested using the reproducer at https://bugzilla.redhat.com/show_bug.cgi?id=867344#c28 Cc: <[email protected]> # 3.6.x Reported-by: Vit Zahradka <[email protected]> Signed-off-by: Sachin Prabhu <[email protected]> --- fs/cifs/dir.c | 11 ++++++++++- 1 files changed, 10 insertions(+), 1 deletions(-) diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c index 7c0a812..d3671f2 100644 --- a/fs/cifs/dir.c +++ b/fs/cifs/dir.c @@ -398,7 +398,16 @@ cifs_atomic_open(struct inode *inode, struct dentry *direntry, * in network traffic in the other paths. */ if (!(oflags & O_CREAT)) { - struct dentry *res = cifs_lookup(inode, direntry, 0); + struct dentry *res; + + /* + * Check for hashed negative dentry. We have already revalidated + * the dentry and it is fine. No need to perform another lookup. + */ + if (!d_unhashed(direntry)) + return -ENOENT; + + res = cifs_lookup(inode, direntry, 0); if (IS_ERR(res)) return PTR_ERR(res); -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
