cifs - check S_AUTOMOUNT in revalidate
authorIan Kent <raven@themaw.net>
Wed, 2 May 2012 11:19:09 +0000 (07:19 -0400)
committerSteve French <sfrench@us.ibm.com>
Thu, 3 May 2012 18:49:47 +0000 (13:49 -0500)
commit936ad9094462578953042d3395b973f1c9e6fa95
tree22d52c9a2489768a9d70d95ef1a99c78185698c3
parent58fa015f611b51e1f501b048bc5ac263c78852f0
cifs - check S_AUTOMOUNT in revalidate

When revalidating a dentry, if the inode wasn't known to be a dfs
entry when the dentry was instantiated, such as when created via
->readdir(), the DCACHE_NEED_AUTOMOUNT flag needs to be set on the
dentry in ->d_revalidate().

The false return from cifs_d_revalidate(), due to the inode now
being marked with the S_AUTOMOUNT flag, might not invalidate the
dentry if there is a concurrent unlazy path walk. This is because
the dentry reference count will be at least 2 in this case causing
d_invalidate() to return EBUSY. So the asumption that the dentry
will be discarded then correctly instantiated via ->lookup() might
not hold.

Signed-off-by: Ian Kent <raven@themaw.net>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Cc: Steve French <smfrench@gmail.com>
Cc: linux-cifs@vger.kernel.org
Signed-off-by: Steve French <sfrench@us.ibm.com>
fs/cifs/dir.c