/* * V9FS cache definitions. * *  Copyright (C) 2009 by Abhishek Kulkarni <adkulkar@umail.iu.edu> * *  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 * */ #include <linux/jiffies.h>#include <linux/file.h>#include <linux/slab.h>#include <linux/stat.h>#include <linux/sched.h>#include <linux/fs.h>#include <net/9p/9p.h> #include "v9fs.h"#include "cache.h" #define CACHETAG_LEN  11 struct fscache_netfs v9fs_cache_netfs = {	.name 		= "9p",	.version 	= 0,}; /** * v9fs_random_cachetag - Generate a random tag to be associated *			  with a new cache session. * * The value of jiffies is used for a fairly randomly cache tag. */ staticint v9fs_random_cachetag(struct v9fs_session_info *v9ses){	v9ses->cachetag = kmalloc(CACHETAG_LEN, GFP_KERNEL);	if (!v9ses->cachetag)		return -ENOMEM; 	return scnprintf(v9ses->cachetag, CACHETAG_LEN, "%lu", jiffies);} static uint16_t v9fs_cache_session_get_key(const void *cookie_netfs_data,					   void *buffer, uint16_t bufmax){	struct v9fs_session_info *v9ses;	uint16_t klen = 0; 	v9ses = (struct v9fs_session_info *)cookie_netfs_data;	p9_debug(P9_DEBUG_FSC, "session %p buf %p size %u\n",		 v9ses, buffer, bufmax); 	if (v9ses->cachetag)		klen = strlen(v9ses->cachetag); 	if (klen > bufmax)		return 0; 	memcpy(buffer, v9ses->cachetag, klen);	p9_debug(P9_DEBUG_FSC, "cache session tag %s\n", v9ses->cachetag);	return klen;} const struct fscache_cookie_def v9fs_cache_session_index_def = {	.name		= "9P.session",	.type		= FSCACHE_COOKIE_TYPE_INDEX,	.get_key	= v9fs_cache_session_get_key,}; void v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses){	/* If no cache session tag was specified, we generate a random one. */	if (!v9ses->cachetag)		v9fs_random_cachetag(v9ses); 	v9ses->fscache = fscache_acquire_cookie(v9fs_cache_netfs.primary_index,						&v9fs_cache_session_index_def,						v9ses);	p9_debug(P9_DEBUG_FSC, "session %p get cookie %p\n",		 v9ses, v9ses->fscache);} void v9fs_cache_session_put_cookie(struct v9fs_session_info *v9ses){	p9_debug(P9_DEBUG_FSC, "session %p put cookie %p\n",		 v9ses, v9ses->fscache);	fscache_relinquish_cookie(v9ses->fscache, 0);	v9ses->fscache = NULL;}  static uint16_t v9fs_cache_inode_get_key(const void *cookie_netfs_data,					 void *buffer, uint16_t bufmax){	const struct v9fs_inode *v9inode = cookie_netfs_data;	memcpy(buffer, &v9inode->qid.path, sizeof(v9inode->qid.path));	p9_debug(P9_DEBUG_FSC, "inode %p get key %llu\n",		 &v9inode->vfs_inode, v9inode->qid.path);	return sizeof(v9inode->qid.path);} static void v9fs_cache_inode_get_attr(const void *cookie_netfs_data,				      uint64_t *size){	const struct v9fs_inode *v9inode = cookie_netfs_data;	*size = i_size_read(&v9inode->vfs_inode); 	p9_debug(P9_DEBUG_FSC, "inode %p get attr %llu\n",		 &v9inode->vfs_inode, *size);} static uint16_t v9fs_cache_inode_get_aux(const void *cookie_netfs_data,					 void *buffer, uint16_t buflen){	const struct v9fs_inode *v9inode = cookie_netfs_data;	memcpy(buffer, &v9inode->qid.version, sizeof(v9inode->qid.version));	p9_debug(P9_DEBUG_FSC, "inode %p get aux %u\n",		 &v9inode->vfs_inode, v9inode->qid.version);	return sizeof(v9inode->qid.version);} static enumfscache_checkaux v9fs_cache_inode_check_aux(void *cookie_netfs_data,					    const void *buffer,					    uint16_t buflen){	const struct v9fs_inode *v9inode = cookie_netfs_data; 	if (buflen != sizeof(v9inode->qid.version))		return FSCACHE_CHECKAUX_OBSOLETE; 	if (memcmp(buffer, &v9inode->qid.version,		   sizeof(v9inode->qid.version)))		return FSCACHE_CHECKAUX_OBSOLETE; 	return FSCACHE_CHECKAUX_OKAY;} static void v9fs_cache_inode_now_uncached(void *cookie_netfs_data){	struct v9fs_inode *v9inode = cookie_netfs_data;	struct pagevec pvec;	pgoff_t first;	int loop, nr_pages; 	pagevec_init(&pvec, 0);	first = 0; 	for (;;) {		nr_pages = pagevec_lookup(&pvec, v9inode->vfs_inode.i_mapping,					  first,					  PAGEVEC_SIZE - pagevec_count(&pvec));		if (!nr_pages)			break; 		for (loop = 0; loop < nr_pages; loop++)			ClearPageFsCache(pvec.pages[loop]); 		first = pvec.pages[nr_pages - 1]->index + 1; 		pvec.nr = nr_pages;		pagevec_release(&pvec);		cond_resched();	}} const struct fscache_cookie_def v9fs_cache_inode_index_def = {	.name		= "9p.inode",	.type		= FSCACHE_COOKIE_TYPE_DATAFILE,	.get_key	= v9fs_cache_inode_get_key,	.get_attr	= v9fs_cache_inode_get_attr,	.get_aux	= v9fs_cache_inode_get_aux,	.check_aux	= v9fs_cache_inode_check_aux,	.now_uncached	= v9fs_cache_inode_now_uncached,}; void v9fs_cache_inode_get_cookie(struct inode *inode){	struct v9fs_inode *v9inode;	struct v9fs_session_info *v9ses; 	if (!S_ISREG(inode->i_mode))		return; 	v9inode = V9FS_I(inode);	if (v9inode->fscache)		return; 	v9ses = v9fs_inode2v9ses(inode);	v9inode->fscache = fscache_acquire_cookie(v9ses->fscache,						  &v9fs_cache_inode_index_def,						  v9inode); 	p9_debug(P9_DEBUG_FSC, "inode %p get cookie %p\n",		 inode, v9inode->fscache);} void v9fs_cache_inode_put_cookie(struct inode *inode){	struct v9fs_inode *v9inode = V9FS_I(inode); 	if (!v9inode->fscache)		return;	p9_debug(P9_DEBUG_FSC, "inode %p put cookie %p\n",		 inode, v9inode->fscache); 	fscache_relinquish_cookie(v9inode->fscache, 0);	v9inode->fscache = NULL;} void v9fs_cache_inode_flush_cookie(struct inode *inode){	struct v9fs_inode *v9inode = V9FS_I(inode); 	if (!v9inode->fscache)		return;	p9_debug(P9_DEBUG_FSC, "inode %p flush cookie %p\n",		 inode, v9inode->fscache); 	fscache_relinquish_cookie(v9inode->fscache, 1);	v9inode->fscache = NULL;} void v9fs_cache_inode_set_cookie(struct inode *inode, struct file *filp){	struct v9fs_inode *v9inode = V9FS_I(inode);	struct p9_fid *fid; 	if (!v9inode->fscache)		return; 	spin_lock(&v9inode->fscache_lock);	fid = filp->private_data;	if ((filp->f_flags & O_ACCMODE) != O_RDONLY)		v9fs_cache_inode_flush_cookie(inode);	else		v9fs_cache_inode_get_cookie(inode); 	spin_unlock(&v9inode->fscache_lock);} void v9fs_cache_inode_reset_cookie(struct inode *inode){	struct v9fs_inode *v9inode = V9FS_I(inode);	struct v9fs_session_info *v9ses;	struct fscache_cookie *old; 	if (!v9inode->fscache)		return; 	old = v9inode->fscache; 	spin_lock(&v9inode->fscache_lock);	fscache_relinquish_cookie(v9inode->fscache, 1); 	v9ses = v9fs_inode2v9ses(inode);	v9inode->fscache = fscache_acquire_cookie(v9ses->fscache,						  &v9fs_cache_inode_index_def,						  v9inode);	p9_debug(P9_DEBUG_FSC, "inode %p revalidating cookie old %p new %p\n",		 inode, old, v9inode->fscache); 	spin_unlock(&v9inode->fscache_lock);} int __v9fs_fscache_release_page(struct page *page, gfp_t gfp){	struct inode *inode = page->mapping->host;	struct v9fs_inode *v9inode = V9FS_I(inode); 	BUG_ON(!v9inode->fscache); 	return fscache_maybe_release_page(v9inode->fscache, page, gfp);} void __v9fs_fscache_invalidate_page(struct page *page){	struct inode *inode = page->mapping->host;	struct v9fs_inode *v9inode = V9FS_I(inode); 	BUG_ON(!v9inode->fscache); 	if (PageFsCache(page)) {		fscache_wait_on_page_write(v9inode->fscache, page);		BUG_ON(!PageLocked(page));		fscache_uncache_page(v9inode->fscache, page);	}} static void v9fs_vfs_readpage_complete(struct page *page, void *data,				       int error){	if (!error)		SetPageUptodate(page); 	unlock_page(page);} /** * __v9fs_readpage_from_fscache - read a page from cache * * Returns 0 if the pages are in cache and a BIO is submitted, * 1 if the pages are not in cache and -error otherwise. */ int __v9fs_readpage_from_fscache(struct inode *inode, struct page *page){	int ret;	const struct v9fs_inode *v9inode = V9FS_I(inode); 	p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page);	if (!v9inode->fscache)		return -ENOBUFS; 	ret = fscache_read_or_alloc_page(v9inode->fscache,					 page,					 v9fs_vfs_readpage_complete,					 NULL,					 GFP_KERNEL);	switch (ret) {	case -ENOBUFS:	case -ENODATA:		p9_debug(P9_DEBUG_FSC, "page/inode not in cache %d\n", ret);		return 1;	case 0:		p9_debug(P9_DEBUG_FSC, "BIO submitted\n");		return ret;	default:		p9_debug(P9_DEBUG_FSC, "ret %d\n", ret);		return ret;	}} /** * __v9fs_readpages_from_fscache - read multiple pages from cache * * Returns 0 if the pages are in cache and a BIO is submitted, * 1 if the pages are not in cache and -error otherwise. */ int __v9fs_readpages_from_fscache(struct inode *inode,				  struct address_space *mapping,				  struct list_head *pages,				  unsigned *nr_pages){	int ret;	const struct v9fs_inode *v9inode = V9FS_I(inode); 	p9_debug(P9_DEBUG_FSC, "inode %p pages %u\n", inode, *nr_pages);	if (!v9inode->fscache)		return -ENOBUFS; 	ret = fscache_read_or_alloc_pages(v9inode->fscache,					  mapping, pages, nr_pages,					  v9fs_vfs_readpage_complete,					  NULL,					  mapping_gfp_mask(mapping));	switch (ret) {	case -ENOBUFS:	case -ENODATA:		p9_debug(P9_DEBUG_FSC, "pages/inodes not in cache %d\n", ret);		return 1;	case 0:		BUG_ON(!list_empty(pages));		BUG_ON(*nr_pages != 0);		p9_debug(P9_DEBUG_FSC, "BIO submitted\n");		return ret;	default:		p9_debug(P9_DEBUG_FSC, "ret %d\n", ret);		return ret;	}} /** * __v9fs_readpage_to_fscache - write a page to the cache * */ void __v9fs_readpage_to_fscache(struct inode *inode, struct page *page){	int ret;	const struct v9fs_inode *v9inode = V9FS_I(inode); 	p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page);	ret = fscache_write_page(v9inode->fscache, page, GFP_KERNEL);	p9_debug(P9_DEBUG_FSC, "ret =  %d\n", ret);	if (ret != 0)		v9fs_uncache_page(inode, page);} /* * wait for a page to complete writing to the cache */void __v9fs_fscache_wait_on_page_write(struct inode *inode, struct page *page){	const struct v9fs_inode *v9inode = V9FS_I(inode);	p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page);	if (PageFsCache(page))		fscache_wait_on_page_write(v9inode->fscache, page);}