[3.13.y-ckt stable] Patch "nfs: if we have no valid attrs, then don't declare the attribute cache valid" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    nfs: if we have no valid attrs, then don't declare the attribute cache valid

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt32.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 299e49eed9326c5aba53fce07c10041743cd6ba2 Mon Sep 17 00:00:00 2001
From: Jeff Layton <jlayton at poochiereds.net>
Date: Wed, 25 Nov 2015 13:50:11 -0500
Subject: nfs: if we have no valid attrs, then don't declare the attribute
 cache valid

commit c812012f9ca7cf89c9e1a1cd512e6c3b5be04b85 upstream.

If we pass in an empty nfs_fattr struct to nfs_update_inode, it will
(correctly) not update any of the attributes, but it then clears the
NFS_INO_INVALID_ATTR flag, which indicates that the attributes are
up to date. Don't clear the flag if the fattr struct has no valid
attrs to apply.

Reviewed-by: Steve French <steve.french at primarydata.com>
Signed-off-by: Jeff Layton <jeff.layton at primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust at primarydata.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 fs/nfs/inode.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 8af210f..3bf36c2 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1624,7 +1624,11 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
 			nfsi->attrtimeo_timestamp = now;
 		}
 	}
-	invalid &= ~NFS_INO_INVALID_ATTR;
+
+	/* Don't declare attrcache up to date if there were no attrs! */
+	if (fattr->valid != 0)
+		invalid &= ~NFS_INO_INVALID_ATTR;
+
 	/* Don't invalidate the data if we were to blame */
 	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)
 				|| S_ISLNK(inode->i_mode)))
--
1.9.1