afs: Populate and use client modification time

BugLink: http://bugs.launchpad.net/bugs/1745052

[ Upstream commit ab94f5d0 ]

The inode timestamps should be set from the client time
in the status received from the server, rather than the
server time which is meant for internal server use.

Set AFS_SET_MTIME and populate the mtime for operations
that take an input status, such as file/dir creation
and StoreData.  If an input time is not provided the
server will set the vnode times based on the current server
time.

In a situation where the server has some skew with the
client, this could lead to the client seeing a timestamp
in the future for a file that it just created or wrote.
Signed-off-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

fs/afs/fsclient.c

@@ -105,7 +105,7 @@ static void xdr_decode_AFSFetchStatus(const __be32 **_bp,
 			vnode->vfs_inode.i_mode = mode;
 		}
 
-		vnode->vfs_inode.i_ctime.tv_sec	= status->mtime_server;
+		vnode->vfs_inode.i_ctime.tv_sec	= status->mtime_client;
 		vnode->vfs_inode.i_mtime	= vnode->vfs_inode.i_ctime;
 		vnode->vfs_inode.i_atime	= vnode->vfs_inode.i_ctime;
 		vnode->vfs_inode.i_version	= data_version;
@@ -703,8 +703,8 @@ int afs_fs_create(struct afs_server *server,
 		memset(bp, 0, padsz);
 		bp = (void *) bp + padsz;
 	}
-	*bp++ = htonl(AFS_SET_MODE);
-	*bp++ = 0; /* mtime */
+	*bp++ = htonl(AFS_SET_MODE | AFS_SET_MTIME);
+	*bp++ = htonl(vnode->vfs_inode.i_mtime.tv_sec); /* mtime */
 	*bp++ = 0; /* owner */
 	*bp++ = 0; /* group */
 	*bp++ = htonl(mode & S_IALLUGO); /* unix mode */
@@ -981,8 +981,8 @@ int afs_fs_symlink(struct afs_server *server,
 		memset(bp, 0, c_padsz);
 		bp = (void *) bp + c_padsz;
 	}
-	*bp++ = htonl(AFS_SET_MODE);
-	*bp++ = 0; /* mtime */
+	*bp++ = htonl(AFS_SET_MODE | AFS_SET_MTIME);
+	*bp++ = htonl(vnode->vfs_inode.i_mtime.tv_sec); /* mtime */
 	*bp++ = 0; /* owner */
 	*bp++ = 0; /* group */
 	*bp++ = htonl(S_IRWXUGO); /* unix mode */
@@ -1192,8 +1192,8 @@ static int afs_fs_store_data64(struct afs_server *server,
 	*bp++ = htonl(vnode->fid.vnode);
 	*bp++ = htonl(vnode->fid.unique);
 
-	*bp++ = 0; /* mask */
-	*bp++ = 0; /* mtime */
+	*bp++ = htonl(AFS_SET_MTIME); /* mask */
+	*bp++ = htonl(vnode->vfs_inode.i_mtime.tv_sec); /* mtime */
 	*bp++ = 0; /* owner */
 	*bp++ = 0; /* group */
 	*bp++ = 0; /* unix mode */
@@ -1269,8 +1269,8 @@ int afs_fs_store_data(struct afs_server *server, struct afs_writeback *wb,
 	*bp++ = htonl(vnode->fid.vnode);
 	*bp++ = htonl(vnode->fid.unique);
 
-	*bp++ = 0; /* mask */
-	*bp++ = 0; /* mtime */
+	*bp++ = htonl(AFS_SET_MTIME); /* mask */
+	*bp++ = htonl(vnode->vfs_inode.i_mtime.tv_sec); /* mtime */
 	*bp++ = 0; /* owner */
 	*bp++ = 0; /* group */
 	*bp++ = 0; /* unix mode */

fs/afs/inode.c

@@ -71,7 +71,7 @@ static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)
 	inode->i_uid		= vnode->status.owner;
 	inode->i_gid            = vnode->status.group;
 	inode->i_size		= vnode->status.size;
-	inode->i_ctime.tv_sec	= vnode->status.mtime_server;
+	inode->i_ctime.tv_sec	= vnode->status.mtime_client;
 	inode->i_ctime.tv_nsec	= 0;
 	inode->i_atime		= inode->i_mtime = inode->i_ctime;
 	inode->i_blocks		= 0;