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Commit 800c06a5 authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust
Browse files

NFS: Add functions to swap transports during migration recovery 



Introduce functions that can walk through an array of returned
fs_locations information and connect a transport to one of the
destination servers listed therein.

Note that NFS minor version 1 introduces "fs_locations_info" which
extends the locations array sorting criteria available to clients.
This is not supported yet.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 32e62b7c

fs/nfs/nfs4_fs.h

+2 −0
Original line number Diff line number Diff line
@@ -217,6 +217,8 @@ rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *); 
struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *, struct inode *, struct qstr *);

struct vfsmount *nfs4_submount(struct nfs_server *, struct dentry *,

			       struct nfs_fh *, struct nfs_fattr *);

int nfs4_replace_transport(struct nfs_server *server,

				const struct nfs4_fs_locations *locations);



/* nfs4proc.c */

extern int nfs4_proc_setclientid(struct nfs_client *, u32, unsigned short, struct rpc_cred *, struct nfs4_setclientid_res *);

fs/nfs/nfs4namespace.c

+101 −0
Original line number Diff line number Diff line
@@ -400,3 +400,104 @@ struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry, 
	rpc_shutdown_client(client);

	return mnt;

}



/*

 * Try one location from the fs_locations array.

 *

 * Returns zero on success, or a negative errno value.

 */

static int nfs4_try_replacing_one_location(struct nfs_server *server,

		char *page, char *page2,

		const struct nfs4_fs_location *location)

{

	const size_t addr_bufsize = sizeof(struct sockaddr_storage);

	struct sockaddr *sap;

	unsigned int s;

	size_t salen;

	int error;



	sap = kmalloc(addr_bufsize, GFP_KERNEL);

	if (sap == NULL)

		return -ENOMEM;



	error = -ENOENT;

	for (s = 0; s < location->nservers; s++) {

		const struct nfs4_string *buf = &location->servers[s];

		char *hostname;



		if (buf->len <= 0 || buf->len > PAGE_SIZE)

			continue;



		if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len) != NULL)

			continue;



		salen = nfs_parse_server_name(buf->data, buf->len,

						sap, addr_bufsize, server);

		if (salen == 0)

			continue;

		rpc_set_port(sap, NFS_PORT);



		error = -ENOMEM;

		hostname = kstrndup(buf->data, buf->len, GFP_KERNEL);

		if (hostname == NULL)

			break;



		error = nfs4_update_server(server, hostname, sap, salen);

		kfree(hostname);

		if (error == 0)

			break;

	}



	kfree(sap);

	return error;

}



/**

 * nfs4_replace_transport - set up transport to destination server

 *

 * @server: export being migrated

 * @locations: fs_locations array

 *

 * Returns zero on success, or a negative errno value.

 *

 * The client tries all the entries in the "locations" array, in the

 * order returned by the server, until one works or the end of the

 * array is reached.

 */

int nfs4_replace_transport(struct nfs_server *server,

			   const struct nfs4_fs_locations *locations)

{

	char *page = NULL, *page2 = NULL;

	int loc, error;



	error = -ENOENT;

	if (locations == NULL || locations->nlocations <= 0)

		goto out;



	error = -ENOMEM;

	page = (char *) __get_free_page(GFP_USER);

	if (!page)

		goto out;

	page2 = (char *) __get_free_page(GFP_USER);

	if (!page2)

		goto out;



	for (loc = 0; loc < locations->nlocations; loc++) {

		const struct nfs4_fs_location *location =

						&locations->locations[loc];



		if (location == NULL || location->nservers <= 0 ||

		    location->rootpath.ncomponents == 0)

			continue;



		error = nfs4_try_replacing_one_location(server, page,

							page2, location);

		if (error == 0)

			break;

	}



out:

	free_page((unsigned long)page);

	free_page((unsigned long)page2);

	return error;

}