android_kernel_xiaomi_sm8350/fs/9p/v9fs_vfs.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

56 lines
2.3 KiB
C

/*
* V9FS VFS extensions.
*
* 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
*
*/
/* plan9 semantics are that created files are implicitly opened.
* But linux semantics are that you call create, then open.
* the plan9 approach is superior as it provides an atomic
* open.
* we track the create fid here. When the file is opened, if fidopen is
* non-zero, we use the fid and can skip some steps.
* there may be a better way to do this, but I don't know it.
* one BAD way is to clunk the fid on create, then open it again:
* you lose the atomicity of file open
*/
/* special case:
* unlink calls remove, which is an implicit clunk. So we have to track
* that kind of thing so that we don't try to clunk a dead fid.
*/
extern struct file_system_type v9fs_fs_type;
extern const struct address_space_operations v9fs_addr_operations;
extern const struct file_operations v9fs_file_operations;
extern const struct file_operations v9fs_cached_file_operations;
extern const struct file_operations v9fs_dir_operations;
extern struct dentry_operations v9fs_dentry_operations;
extern struct dentry_operations v9fs_cached_dentry_operations;
struct inode *v9fs_get_inode(struct super_block *sb, int mode);
ino_t v9fs_qid2ino(struct v9fs_qid *qid);
void v9fs_stat2inode(struct v9fs_stat *, struct inode *, struct super_block *);
int v9fs_dir_release(struct inode *inode, struct file *filp);
int v9fs_file_open(struct inode *inode, struct file *file);
void v9fs_inode2stat(struct inode *inode, struct v9fs_stat *stat);
void v9fs_dentry_release(struct dentry *);
int v9fs_uflags2omode(int uflags);