[3.16.y-ckt stable] Patch "NFS: Don't revalidate the mapping if both size and change attr are up to date" has been added to staging queue

[Luis Henriques]

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

    NFS: Don't revalidate the mapping if both size and change attr are up to date

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt17.

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

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 6affaeba01c2a0127b890eb28b0f1fc5184ad12f Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust at primarydata.com>
Date: Sun, 5 Jul 2015 11:02:53 -0400
Subject: NFS: Don't revalidate the mapping if both size and change attr are up
 to date

commit 85a23cee3f2c928475f31777ead5a71340a12fc3 upstream.

If we've ensured that the size and the change attribute are both correct,
then there is no point in marking those attributes as needing revalidation
again. Only do so if we know the size is incorrect and was not updated.

Fixes: f2467b6f64da ("NFS: Clear NFS_INO_REVAL_PAGECACHE when...")
Signed-off-by: Trond Myklebust <trond.myklebust at primarydata.com>
[ luis: backported to 3.16:
  - use 'nfsi->npages' instead of 'nfsi->nrequests' ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/nfs/inode.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index aa6daf535dec..fa8d1b632d49 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1179,9 +1179,11 @@ static int nfs_check_inode_attributes(struct inode *inode, struct nfs_fattr *fat
 	if (fattr->valid & NFS_ATTR_FATTR_SIZE) {
 		cur_size = i_size_read(inode);
 		new_isize = nfs_size_to_loff_t(fattr->size);
-		if (cur_size != new_isize && nfsi->npages == 0)
+		if (cur_size != new_isize)
 			invalid |= NFS_INO_INVALID_ATTR|NFS_INO_REVAL_PAGECACHE;
 	}
+	if (nfsi->npages != 0)
+		invalid &= ~NFS_INO_REVAL_PAGECACHE;

 	/* Have any file permissions changed? */
 	if ((fattr->valid & NFS_ATTR_FATTR_MODE) && (inode->i_mode & S_IALLUGO) != (fattr->mode & S_IALLUGO))
@@ -1576,8 +1578,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
 			invalid |= NFS_INO_INVALID_ATTR
 				| NFS_INO_INVALID_DATA
 				| NFS_INO_INVALID_ACCESS
-				| NFS_INO_INVALID_ACL
-				| NFS_INO_REVAL_PAGECACHE;
+				| NFS_INO_INVALID_ACL;
 			if (S_ISDIR(inode->i_mode))
 				nfs_force_lookup_revalidate(inode);
 			inode->i_version = fattr->change_attr;
@@ -1609,7 +1610,6 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
 			if ((nfsi->npages == 0) || new_isize > cur_isize) {
 				i_size_write(inode, new_isize);
 				invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA;
-				invalid &= ~NFS_INO_REVAL_PAGECACHE;
 			}
 			dprintk("NFS: isize change on server for file %s/%ld "
 					"(%Ld to %Ld)\n",