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Commit 3a1c13e1 authored by Trond Myklebust's avatar Trond Myklebust Committed by Greg Kroah-Hartman
Browse files

NFSv4.1: Fix the r/wsize checking 



commit 943cff67b842839f4f35364ba2db5c2d3f025d94 upstream.

The intention of nfs4_session_set_rwsize() was to cap the r/wsize to the
buffer sizes negotiated by the CREATE_SESSION. The initial code had a
bug whereby we would not check the values negotiated by nfs_probe_fsinfo()
(the assumption being that CREATE_SESSION will always negotiate buffer values
that are sane w.r.t. the server's preferred r/wsizes) but would only check
values set by the user in the 'mount' command.

The code was changed in 4.11 to _always_ set the r/wsize, meaning that we
now never use the server preferred r/wsizes. This is the regression that
this patch fixes.
Also rename the function to nfs4_session_limit_rwsize() in order to avoid
future confusion.

Fixes: 03385332 (NFSv4.1 respect server's max size in CREATE_SESSION")
Cc: stable@vger.kernel.org # v4.11+
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d9e1cdc8

fs/nfs/nfs4client.c

+9 −7
Original line number Diff line number Diff line
@@ -950,10 +950,10 @@ EXPORT_SYMBOL_GPL(nfs4_set_ds_client); 


/*

 * Session has been established, and the client marked ready.

 * Set the mount rsize and wsize with negotiated fore channel

 * attributes which will be bound checked in nfs_server_set_fsinfo.

 * Limit the mount rsize, wsize and dtsize using negotiated fore

 * channel attributes.

 */

static void nfs4_session_set_rwsize(struct nfs_server *server)

static void nfs4_session_limit_rwsize(struct nfs_server *server)

{

#ifdef CONFIG_NFS_V4_1

	struct nfs4_session *sess;
@@ -966,9 +966,11 @@ static void nfs4_session_set_rwsize(struct nfs_server *server) 
	server_resp_sz = sess->fc_attrs.max_resp_sz - nfs41_maxread_overhead;

	server_rqst_sz = sess->fc_attrs.max_rqst_sz - nfs41_maxwrite_overhead;



	if (!server->rsize || server->rsize > server_resp_sz)

	if (server->dtsize > server_resp_sz)

		server->dtsize = server_resp_sz;

	if (server->rsize > server_resp_sz)

		server->rsize = server_resp_sz;

	if (!server->wsize || server->wsize > server_rqst_sz)

	if (server->wsize > server_rqst_sz)

		server->wsize = server_rqst_sz;

#endif /* CONFIG_NFS_V4_1 */

}
@@ -1015,12 +1017,12 @@ static int nfs4_server_common_setup(struct nfs_server *server, 
			(unsigned long long) server->fsid.minor);

	nfs_display_fhandle(mntfh, "Pseudo-fs root FH");



	nfs4_session_set_rwsize(server);



	error = nfs_probe_fsinfo(server, mntfh, fattr);

	if (error < 0)

		goto out;



	nfs4_session_limit_rwsize(server);



	if (server->namelen == 0 || server->namelen > NFS4_MAXNAMLEN)

		server->namelen = NFS4_MAXNAMLEN;