kernel-ark/fs/9p/v9fs.h
Eric Van Hensbergen e03abc0c96 9p: implement optional loose read cache
While cacheing is generally frowned upon in the 9p world, it has its
place -- particularly in situations where the remote file system is
exclusive and/or read-only.  The vacfs views of venti content addressable
store are a real-world instance of such a situation.  To facilitate higher
performance for these workloads (and eventually use the fscache patches),
we have enabled a "loose" cache mode which does not attempt to maintain
any form of consistency on the page-cache or dcache.  This results in over
two orders of magnitude performance improvement for cacheable block reads
in the Bonnie benchmark.  The more aggressive use of the dcache also seems
to improve metadata operational performance.

Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
2007-02-18 10:16:10 -06:00

100 lines
2.9 KiB
C

/*
* V9FS definitions.
*
* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to:
* Free Software Foundation
* 51 Franklin Street, Fifth Floor
* Boston, MA 02111-1301 USA
*
*/
/*
* Idpool structure provides lock and id management
*
*/
struct v9fs_idpool {
struct semaphore lock;
struct idr pool;
};
/*
* Session structure provides information for an opened session
*
*/
struct v9fs_session_info {
/* options */
unsigned int maxdata;
unsigned char extended; /* set to 1 if we are using UNIX extensions */
unsigned char nodev; /* set to 1 if no disable device mapping */
unsigned short port; /* port to connect to */
unsigned short debug; /* debug level */
unsigned short proto; /* protocol to use */
unsigned int afid; /* authentication fid */
unsigned int rfdno; /* read file descriptor number */
unsigned int wfdno; /* write file descriptor number */
unsigned int cache; /* cache mode */
char *name; /* user name to mount as */
char *remotename; /* name of remote hierarchy being mounted */
unsigned int uid; /* default uid/muid for legacy support */
unsigned int gid; /* default gid for legacy support */
/* book keeping */
struct v9fs_idpool fidpool; /* The FID pool for file descriptors */
struct v9fs_transport *transport;
struct v9fs_mux_data *mux;
int inprogress; /* session in progress => true */
int shutdown; /* session shutting down. no more attaches. */
unsigned char session_hung;
struct dentry *debugfs_dir;
};
/* possible values of ->proto */
enum {
PROTO_TCP,
PROTO_UNIX,
PROTO_FD,
};
/* possible values of ->cache */
/* eventually support loose, tight, time, session, default always none */
enum {
CACHE_NONE, /* default */
CACHE_LOOSE, /* no consistency */
};
extern struct dentry *v9fs_debugfs_root;
int v9fs_session_init(struct v9fs_session_info *, const char *, char *);
struct v9fs_session_info *v9fs_inode2v9ses(struct inode *);
void v9fs_session_close(struct v9fs_session_info *v9ses);
int v9fs_get_idpool(struct v9fs_idpool *p);
void v9fs_put_idpool(int id, struct v9fs_idpool *p);
int v9fs_check_idpool(int id, struct v9fs_idpool *p);
void v9fs_session_cancel(struct v9fs_session_info *v9ses);
#define V9FS_MAGIC 0x01021997
/* other default globals */
#define V9FS_PORT 564
#define V9FS_DEFUSER "nobody"
#define V9FS_DEFANAME ""