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 | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c index 7c0a812..e26d0a6 100644 --- a/fs/cifs/dir.c +++ b/fs/cifs/dir.c @@ -398,6 +398,12 @@ cifs_atomic_open(struct inode *inode, struct dentry *direntry, * in network traffic in the other paths. */ if (!(oflags & O_CREAT)) { + /* 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; + struct dentry *res = cifs_lookup(inode, direntry, 0); if (IS_ERR(res)) return PTR_ERR(res); -- 1.7.11.7 -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
