Re: [RFC][PATCH 04/10] cifs: define server-level cache index objects and register them with FS-Cache

[Jeff Layton <jlayton-vpEMnDpepFuMZCB2o+C8xQ@public.gmane.org>]

On Tue, 22 Jun 2010 20:53:18 +0530
Suresh Jayaraman <sjayaraman-l3A5Bk7waGM@public.gmane.org> wrote:

> Define server-level cache index objects (as managed by TCP_ServerInfo structs).
> Each server object is created in the CIFS top-level index object and is itself
> an index into which superblock-level objects are inserted.
> 
> Currently, the server objects are keyed by hostname.
> 
> Signed-off-by: Suresh Jayaraman <sjayaraman-l3A5Bk7waGM@public.gmane.org>
> ---
>  fs/cifs/Makefile   |    2 +-
>  fs/cifs/cache.c    |   25 +++++++++++++++++++++++++
>  fs/cifs/cifsglob.h |    3 +++
>  fs/cifs/connect.c  |    4 ++++
>  fs/cifs/fscache.c  |   47 +++++++++++++++++++++++++++++++++++++++++++++++
>  fs/cifs/fscache.h  |   12 ++++++++++++
>  6 files changed, 92 insertions(+), 1 deletion(-)
>  create mode 100644 fs/cifs/fscache.c
> 
> Index: cifs-2.6/fs/cifs/Makefile
> ===================================================================
> --- cifs-2.6.orig/fs/cifs/Makefile
> +++ cifs-2.6/fs/cifs/Makefile
> @@ -12,4 +12,4 @@ cifs-$(CONFIG_CIFS_UPCALL) += cifs_spneg
>  
>  cifs-$(CONFIG_CIFS_DFS_UPCALL) += dns_resolve.o cifs_dfs_ref.o
>  
> -cifs-$(CONFIG_CIFS_FSCACHE) += cache.o
> +cifs-$(CONFIG_CIFS_FSCACHE) += fscache.o cache.o
> Index: cifs-2.6/fs/cifs/cache.c
> ===================================================================
> --- cifs-2.6.orig/fs/cifs/cache.c
> +++ cifs-2.6/fs/cifs/cache.c
> @@ -51,3 +51,28 @@ void cifs_fscache_unregister(void)
>  	fscache_unregister_netfs(&cifs_fscache_netfs);
>  }
>  
> +/*
> + * Server object currently keyed by hostname
> + */
> +static uint16_t cifs_server_get_key(const void *cookie_netfs_data,
> +				   void *buffer, uint16_t maxbuf)
> +{
> +	const struct TCP_Server_Info *server = cookie_netfs_data;
> +	uint16_t len = strnlen(server->hostname, sizeof(server->hostname));
> +

Would a tuple of address/family/port be a better choice here? Imagine I
mount "foo" and then later mount "foor.bar.baz". If they are the same
address and only the UNC differs, then you won't get the benefit of
the cache, right?

> +	if (len > maxbuf)
> +		return 0;
> +
> +	memcpy(buffer, server->hostname, len);
> +
> +	return len;
> +}
> +
> +/*
> + * Server object for FS-Cache
> + */
> +const struct fscache_cookie_def cifs_fscache_server_index_def = {
> +	.name = "CIFS.server",
> +	.type = FSCACHE_COOKIE_TYPE_INDEX,
> +	.get_key = cifs_server_get_key,
> +};
> Index: cifs-2.6/fs/cifs/cifsglob.h
> ===================================================================
> --- cifs-2.6.orig/fs/cifs/cifsglob.h
> +++ cifs-2.6/fs/cifs/cifsglob.h
> @@ -193,6 +193,9 @@ struct TCP_Server_Info {
>  	bool	sec_mskerberos;		/* supports legacy MS Kerberos */
>  	bool	sec_kerberosu2u;	/* supports U2U Kerberos */
>  	bool	sec_ntlmssp;		/* supports NTLMSSP */
> +#ifdef CONFIG_CIFS_FSCACHE
> +	struct fscache_cookie   *fscache; /* client index cache cookie */
> +#endif
>  };
>  
>  /*
> Index: cifs-2.6/fs/cifs/connect.c
> ===================================================================
> --- cifs-2.6.orig/fs/cifs/connect.c
> +++ cifs-2.6/fs/cifs/connect.c
> @@ -48,6 +48,7 @@
>  #include "nterr.h"
>  #include "rfc1002pdu.h"
>  #include "cn_cifs.h"
> +#include "fscache.h"
>  
>  #define CIFS_PORT 445
>  #define RFC1001_PORT 139
> @@ -1453,6 +1454,8 @@ cifs_put_tcp_session(struct TCP_Server_I
>  		return;
>  	}
>  
> +	cifs_fscache_release_client_cookie(server);
> +
>  	list_del_init(&server->tcp_ses_list);
>  	write_unlock(&cifs_tcp_ses_lock);
>  
> @@ -1572,6 +1575,7 @@ cifs_get_tcp_session(struct smb_vol *vol
>  		goto out_err;
>  	}
>  
> +	cifs_fscache_get_client_cookie(tcp_ses);
>  	/* thread spawned, put it on the list */
>  	write_lock(&cifs_tcp_ses_lock);
>  	list_add(&tcp_ses->tcp_ses_list, &cifs_tcp_ses_list);
> Index: cifs-2.6/fs/cifs/fscache.c
> ===================================================================
> --- /dev/null
> +++ cifs-2.6/fs/cifs/fscache.c
> @@ -0,0 +1,47 @@
> +/*
> + *   fs/cifs/fscache.c - CIFS filesystem cache interface
> + *
> + *   Copyright (c) 2010 Novell, Inc.
> + *   Authors(s): Suresh Jayaraman (sjayaraman-l3A5Bk7waGM@public.gmane.org>
> + *
> + *   This library is free software; you can redistribute it and/or modify
> + *   it under the terms of the GNU Lesser General Public License as published
> + *   by the Free Software Foundation; either version 2.1 of the License, or
> + *   (at your option) any later version.
> + *
> + *   This library is distributed in the hope that it will be useful,
> + *   but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
> + *   the GNU Lesser General Public License for more details.
> + *
> + *   You should have received a copy of the GNU Lesser General Public License
> + *   along with this library; if not, write to the Free Software
> + *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
> + */
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/sched.h>
> +#include <linux/mm.h>
> +#include <linux/in6.h>
> +
> +#include "fscache.h"
> +#include "cifsglob.h"
> +#include "cifs_debug.h"
> +
> +void cifs_fscache_get_client_cookie(struct TCP_Server_Info *server)
> +{
> +	server->fscache =
> +		fscache_acquire_cookie(cifs_fscache_netfs.primary_index,
> +				&cifs_fscache_server_index_def, server);
> +	cFYI(1, "CIFS: get client cookie (0x%p/0x%p)\n",
> +				server, server->fscache);
> +}
> +
> +void cifs_fscache_release_client_cookie(struct TCP_Server_Info *server)
> +{
> +	cFYI(1, "CIFS: release client cookie (0x%p/0x%p)\n",
> +				server, server->fscache);
> +	fscache_relinquish_cookie(server->fscache, 0);
> +	server->fscache = NULL;
> +}
> +
> Index: cifs-2.6/fs/cifs/fscache.h
> ===================================================================
> --- cifs-2.6.orig/fs/cifs/fscache.h
> +++ cifs-2.6/fs/cifs/fscache.h
> @@ -27,14 +27,26 @@
>  #ifdef CONFIG_CIFS_FSCACHE
>  
>  extern struct fscache_netfs cifs_fscache_netfs;
> +extern const struct fscache_cookie_def cifs_fscache_server_index_def;
>  
>  extern int cifs_fscache_register(void);
>  extern void cifs_fscache_unregister(void);
>  
> +/*
> + * fscache.c
> + */
> +extern void cifs_fscache_get_client_cookie(struct TCP_Server_Info *);
> +extern void cifs_fscache_release_client_cookie(struct TCP_Server_Info *);
> +
>  #else /* CONFIG_CIFS_FSCACHE */
>  static inline int cifs_fscache_register(void) { return 0; }
>  static inline void cifs_fscache_unregister(void) {}
>  
> +static inline void
> +cifs_fscache_get_client_cookie(struct TCP_Server_Info *server) {}
> +static inline void
> +cifs_fscache_get_client_cookie(struct TCP_Server_Info *server); {}
> +
>  #endif /* CONFIG_CIFS_FSCACHE */
>  
>  #endif /* _CIFS_FSCACHE_H */
> --
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-- 
Jeff Layton <jlayton-vpEMnDpepFuMZCB2o+C8xQ@public.gmane.org>