linux-kernel - [PATCH 3.16 141/212] nfsd: update mtime on truncate

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Date:   Thu, 01 Jun 2017 16:43:16 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Christoph Hellwig" <hch@....de>,
        "J. Bruce Fields" <bfields@...hat.com>
Subject: [PATCH 3.16 141/212] nfsd: update mtime on truncate

3.16.44-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Christoph Hellwig <hch@....de>

commit f0c63124a6165792f6e37e4b5983792d009e1ce8 upstream.

This fixes a failure in xfstests generic/313 because nfs doesn't update
mtime on a truncate.  The protocol requires this to be done implicity
for a size changing setattr.

Signed-off-by: Christoph Hellwig <hch@....de>
Signed-off-by: J. Bruce Fields <bfields@...hat.com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 fs/nfsd/vfs.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -448,6 +448,16 @@ nfsd_setattr(struct svc_rqst *rqstp, str
 		if (err)
 			goto out;
 		size_change = 1;
+
+		/*
+		 * RFC5661, Section 18.30.4:
+		 *   Changing the size of a file with SETATTR indirectly
+		 *   changes the time_modify and change attributes.
+		 *
+		 * (and similar for the older RFCs)
+		 */
+		if (iap->ia_size != i_size_read(inode))
+			iap->ia_valid |= ATTR_MTIME;
 	}
 
 	iap->ia_valid |= ATTR_CTIME;