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Commit 0b524123 authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust
Browse files

NFS: Add ability to send MOUNTPROC_UMNT to the kernel's mountd client 



After certain failure modes of an NFS mount, an NFS client should send
a MOUNTPROC_UMNT request to remove the just-added mount entry from the
server's mount table.  While no-one should rely on the accuracy of the
server's mount table, sending a UMNT is simply being a good internet
neighbor.

Since NFS mount processing is handled in the kernel now, we will need
a function in the kernel's mountd client that can post a MOUNTRPC_UMNT
request, in order to handle these failure modes.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent f3f4f4ed

fs/nfs/internal.h

+1 −0
Original line number Diff line number Diff line
@@ -102,6 +102,7 @@ struct nfs_mount_request { 
};



extern int nfs_mount(struct nfs_mount_request *info);

extern void nfs_umount(const struct nfs_mount_request *info);



/* client.c */

extern struct rpc_program nfs_program;

fs/nfs/mount_clnt.c

+79 −0
Original line number Diff line number Diff line
@@ -209,6 +209,71 @@ int nfs_mount(struct nfs_mount_request *info) 
	goto out;

}



/**

 * nfs_umount - Notify a server that we have unmounted this export

 * @info: pointer to umount request arguments

 *

 * MOUNTPROC_UMNT is advisory, so we set a short timeout, and always

 * use UDP.

 */

void nfs_umount(const struct nfs_mount_request *info)

{

	static const struct rpc_timeout nfs_umnt_timeout = {

		.to_initval = 1 * HZ,

		.to_maxval = 3 * HZ,

		.to_retries = 2,

	};

	struct rpc_create_args args = {

		.protocol	= IPPROTO_UDP,

		.address	= info->sap,

		.addrsize	= info->salen,

		.timeout	= &nfs_umnt_timeout,

		.servername	= info->hostname,

		.program	= &mnt_program,

		.version	= info->version,

		.authflavor	= RPC_AUTH_UNIX,

		.flags		= RPC_CLNT_CREATE_NOPING,

	};

	struct mountres	result;

	struct rpc_message msg	= {

		.rpc_argp	= info->dirpath,

		.rpc_resp	= &result,

	};

	struct rpc_clnt *clnt;

	int status;



	if (info->noresvport)

		args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;



	clnt = rpc_create(&args);

	if (unlikely(IS_ERR(clnt)))

		goto out_clnt_err;



	dprintk("NFS: sending UMNT request for %s:%s\n",

		(info->hostname ? info->hostname : "server"), info->dirpath);



	if (info->version == NFS_MNT3_VERSION)

		msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC3_UMNT];

	else

		msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC_UMNT];



	status = rpc_call_sync(clnt, &msg, 0);

	rpc_shutdown_client(clnt);



	if (unlikely(status < 0))

		goto out_call_err;



	return;



out_clnt_err:

	dprintk("NFS: failed to create UMNT RPC client, status=%ld\n",

			PTR_ERR(clnt));

	return;



out_call_err:

	dprintk("NFS: UMNT request failed, status=%d\n", status);

}



/*

 * XDR encode/decode functions for MOUNT

 */
@@ -407,6 +472,13 @@ static struct rpc_procinfo mnt_procedures[] = { 
		.p_statidx	= MOUNTPROC_MNT,

		.p_name		= "MOUNT",

	},

	[MOUNTPROC_UMNT] = {

		.p_proc		= MOUNTPROC_UMNT,

		.p_encode	= (kxdrproc_t)mnt_enc_dirpath,

		.p_arglen	= MNT_enc_dirpath_sz,

		.p_statidx	= MOUNTPROC_UMNT,

		.p_name		= "UMOUNT",

	},

};



static struct rpc_procinfo mnt3_procedures[] = {
@@ -419,6 +491,13 @@ static struct rpc_procinfo mnt3_procedures[] = { 
		.p_statidx	= MOUNTPROC3_MNT,

		.p_name		= "MOUNT",

	},

	[MOUNTPROC3_UMNT] = {

		.p_proc		= MOUNTPROC3_UMNT,

		.p_encode	= (kxdrproc_t)mnt_enc_dirpath,

		.p_arglen	= MNT_enc_dirpath_sz,

		.p_statidx	= MOUNTPROC3_UMNT,

		.p_name		= "UMOUNT",

	},

};