60e78d2c99
This patch adds a persistent, read-only caching facility for 9p clients using the FS-Cache caching backend. When the fscache facility is enabled, each inode is associated with a corresponding vcookie which is an index into the FS-Cache indexing tree. The FS-Cache indexing tree is indexed at 3 levels: - session object associated with each mount. - inode/vcookie - actual data (pages) A cache tag is chosen randomly for each session. These tags can be read off /sys/fs/9p/caches and can be passed as a mount-time parameter to re-attach to the specified caching session. Signed-off-by: Abhishek Kulkarni <adkulkar@umail.iu.edu> Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
176 lines
4.8 KiB
C
176 lines
4.8 KiB
C
/*
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* V9FS cache definitions.
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*
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* Copyright (C) 2009 by Abhishek Kulkarni <adkulkar@umail.iu.edu>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to:
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* Free Software Foundation
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* 51 Franklin Street, Fifth Floor
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* Boston, MA 02111-1301 USA
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*
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*/
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#ifndef _9P_CACHE_H
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#ifdef CONFIG_9P_FSCACHE
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#include <linux/fscache.h>
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#include <linux/spinlock.h>
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extern struct kmem_cache *vcookie_cache;
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struct v9fs_cookie {
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spinlock_t lock;
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struct inode inode;
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struct fscache_cookie *fscache;
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struct p9_qid *qid;
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};
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static inline struct v9fs_cookie *v9fs_inode2cookie(const struct inode *inode)
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{
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return container_of(inode, struct v9fs_cookie, inode);
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}
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extern struct fscache_netfs v9fs_cache_netfs;
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extern const struct fscache_cookie_def v9fs_cache_session_index_def;
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extern const struct fscache_cookie_def v9fs_cache_inode_index_def;
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extern void v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses);
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extern void v9fs_cache_session_put_cookie(struct v9fs_session_info *v9ses);
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extern void v9fs_cache_inode_get_cookie(struct inode *inode);
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extern void v9fs_cache_inode_put_cookie(struct inode *inode);
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extern void v9fs_cache_inode_flush_cookie(struct inode *inode);
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extern void v9fs_cache_inode_set_cookie(struct inode *inode, struct file *filp);
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extern void v9fs_cache_inode_reset_cookie(struct inode *inode);
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extern int __v9fs_cache_register(void);
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extern void __v9fs_cache_unregister(void);
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extern int __v9fs_fscache_release_page(struct page *page, gfp_t gfp);
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extern void __v9fs_fscache_invalidate_page(struct page *page);
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extern int __v9fs_readpage_from_fscache(struct inode *inode,
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struct page *page);
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extern int __v9fs_readpages_from_fscache(struct inode *inode,
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struct address_space *mapping,
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struct list_head *pages,
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unsigned *nr_pages);
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extern void __v9fs_readpage_to_fscache(struct inode *inode, struct page *page);
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/**
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* v9fs_cache_register - Register v9fs file system with the cache
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*/
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static inline int v9fs_cache_register(void)
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{
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return __v9fs_cache_register();
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}
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/**
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* v9fs_cache_unregister - Unregister v9fs from the cache
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*/
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static inline void v9fs_cache_unregister(void)
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{
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__v9fs_cache_unregister();
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}
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static inline int v9fs_fscache_release_page(struct page *page,
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gfp_t gfp)
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{
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return __v9fs_fscache_release_page(page, gfp);
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}
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static inline void v9fs_fscache_invalidate_page(struct page *page)
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{
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__v9fs_fscache_invalidate_page(page);
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}
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static inline int v9fs_readpage_from_fscache(struct inode *inode,
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struct page *page)
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{
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return __v9fs_readpage_from_fscache(inode, page);
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}
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static inline int v9fs_readpages_from_fscache(struct inode *inode,
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struct address_space *mapping,
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struct list_head *pages,
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unsigned *nr_pages)
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{
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return __v9fs_readpages_from_fscache(inode, mapping, pages,
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nr_pages);
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}
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static inline void v9fs_readpage_to_fscache(struct inode *inode,
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struct page *page)
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{
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if (PageFsCache(page))
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__v9fs_readpage_to_fscache(inode, page);
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}
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static inline void v9fs_uncache_page(struct inode *inode, struct page *page)
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{
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struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
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fscache_uncache_page(vcookie->fscache, page);
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BUG_ON(PageFsCache(page));
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}
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static inline void v9fs_vcookie_set_qid(struct inode *inode,
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struct p9_qid *qid)
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{
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struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
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spin_lock(&vcookie->lock);
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vcookie->qid = qid;
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spin_unlock(&vcookie->lock);
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}
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#else /* CONFIG_9P_FSCACHE */
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static inline int v9fs_cache_register(void)
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{
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return 1;
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}
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static inline void v9fs_cache_unregister(void) {}
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static inline int v9fs_fscache_release_page(struct page *page,
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gfp_t gfp) {
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return 1;
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}
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static inline void v9fs_fscache_invalidate_page(struct page *page) {}
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static inline int v9fs_readpage_from_fscache(struct inode *inode,
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struct page *page)
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{
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return -ENOBUFS;
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}
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static inline int v9fs_readpages_from_fscache(struct inode *inode,
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struct address_space *mapping,
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struct list_head *pages,
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unsigned *nr_pages)
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{
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return -ENOBUFS;
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}
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static inline void v9fs_readpage_to_fscache(struct inode *inode,
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struct page *page)
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{}
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static inline void v9fs_uncache_page(struct inode *inode, struct page *page)
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{}
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static inline void v9fs_vcookie_set_qid(struct inode *inode,
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struct p9_qid *qid)
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{}
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#endif /* CONFIG_9P_FSCACHE */
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#endif /* _9P_CACHE_H */
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