[deliverable/linux.git] / fs / 9p / cache.c

/*
 * 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.
 */

static
int 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_DPRINTK(P9_DEBUG_FSC, "session %p buf %p size %u", v9ses,
		   buffer, bufmax);

	if (v9ses->cachetag)
		klen = strlen(v9ses->cachetag);

	if (klen > bufmax)
		return 0;

	memcpy(buffer, v9ses->cachetag, klen);
	P9_DPRINTK(P9_DEBUG_FSC, "cache session tag %s", 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_DPRINTK(P9_DEBUG_FSC, "session %p get cookie %p", v9ses,
		   v9ses->fscache);
}

void v9fs_cache_session_put_cookie(struct v9fs_session_info *v9ses)
{
	P9_DPRINTK(P9_DEBUG_FSC, "session %p put cookie %p", 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->fscache_key->path,
	       sizeof(v9inode->fscache_key->path));
	P9_DPRINTK(P9_DEBUG_FSC, "inode %p get key %llu", &v9inode->vfs_inode,
		   v9inode->fscache_key->path);
	return sizeof(v9inode->fscache_key->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_DPRINTK(P9_DEBUG_FSC, "inode %p get attr %llu", &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->fscache_key->version,
	       sizeof(v9inode->fscache_key->version));
	P9_DPRINTK(P9_DEBUG_FSC, "inode %p get aux %u", &v9inode->vfs_inode,
		   v9inode->fscache_key->version);
	return sizeof(v9inode->fscache_key->version);
}

static enum
fscache_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->fscache_key->version))
		return FSCACHE_CHECKAUX_OBSOLETE;

	if (memcmp(buffer, &v9inode->fscache_key->version,
		   sizeof(v9inode->fscache_key->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_DPRINTK(P9_DEBUG_FSC, "inode %p get cookie %p", inode,
		   v9inode->fscache);
}

void v9fs_cache_inode_put_cookie(struct inode *inode)
{
	struct v9fs_inode *v9inode = V9FS_I(inode);

	if (!v9inode->fscache)
		return;
	P9_DPRINTK(P9_DEBUG_FSC, "inode %p put cookie %p", 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_DPRINTK(P9_DEBUG_FSC, "inode %p flush cookie %p", 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_DPRINTK(P9_DEBUG_FSC, "inode %p revalidating cookie old %p new %p",
		   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_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", 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_DPRINTK(P9_DEBUG_FSC, "page/inode not in cache %d", ret);
		return 1;
	case 0:
		P9_DPRINTK(P9_DEBUG_FSC, "BIO submitted");
		return ret;
	default:
		P9_DPRINTK(P9_DEBUG_FSC, "ret %d", 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_DPRINTK(P9_DEBUG_FSC, "inode %p pages %u", 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_DPRINTK(P9_DEBUG_FSC, "pages/inodes not in cache %d", ret);
		return 1;
	case 0:
		BUG_ON(!list_empty(pages));
		BUG_ON(*nr_pages != 0);
		P9_DPRINTK(P9_DEBUG_FSC, "BIO submitted");
		return ret;
	default:
		P9_DPRINTK(P9_DEBUG_FSC, "ret %d", 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_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
	ret = fscache_write_page(v9inode->fscache, page, GFP_KERNEL);
	P9_DPRINTK(P9_DEBUG_FSC, "ret =  %d", 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_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
	if (PageFsCache(page))
		fscache_wait_on_page_write(v9inode->fscache, page);
}
Commit	Line	Data
60e78d2c AK	1	/*
	2	* V9FS cache definitions.
	3	*
	4	* Copyright (C) 2009 by Abhishek Kulkarni <adkulkar@umail.iu.edu>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2
	8	* as published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program; if not, write to:
	17	* Free Software Foundation
	18	* 51 Franklin Street, Fifth Floor
	19	* Boston, MA 02111-1301 USA
	20	*
	21	*/
	22
	23	#include <linux/jiffies.h>
	24	#include <linux/file.h>
5a0e3ad6	25	#include <linux/slab.h>
60e78d2c AK	26	#include <linux/stat.h>
	27	#include <linux/sched.h>
	28	#include <linux/fs.h>
	29	#include <net/9p/9p.h>
	30
	31	#include "v9fs.h"
	32	#include "cache.h"
	33
	34	#define CACHETAG_LEN 11
	35
60e78d2c AK	36	struct fscache_netfs v9fs_cache_netfs = {
	37	.name = "9p",
	38	.version = 0,
	39	};
	40
60e78d2c AK	41	/**
	42	* v9fs_random_cachetag - Generate a random tag to be associated
	43	* with a new cache session.
	44	*
	45	* The value of jiffies is used for a fairly randomly cache tag.
	46	*/
	47
	48	static
	49	int v9fs_random_cachetag(struct v9fs_session_info *v9ses)
	50	{
	51	v9ses->cachetag = kmalloc(CACHETAG_LEN, GFP_KERNEL);
	52	if (!v9ses->cachetag)
	53	return -ENOMEM;
	54
	55	return scnprintf(v9ses->cachetag, CACHETAG_LEN, "%lu", jiffies);
	56	}
	57
	58	static uint16_t v9fs_cache_session_get_key(const void *cookie_netfs_data,
	59	void *buffer, uint16_t bufmax)
	60	{
	61	struct v9fs_session_info *v9ses;
	62	uint16_t klen = 0;
	63
	64	v9ses = (struct v9fs_session_info *)cookie_netfs_data;
	65	P9_DPRINTK(P9_DEBUG_FSC, "session %p buf %p size %u", v9ses,
	66	buffer, bufmax);
	67
	68	if (v9ses->cachetag)
	69	klen = strlen(v9ses->cachetag);
	70
	71	if (klen > bufmax)
	72	return 0;
	73
	74	memcpy(buffer, v9ses->cachetag, klen);
	75	P9_DPRINTK(P9_DEBUG_FSC, "cache session tag %s", v9ses->cachetag);
	76	return klen;
	77	}
	78
	79	const struct fscache_cookie_def v9fs_cache_session_index_def = {
a78ce05d AK	80	.name = "9P.session",
	81	.type = FSCACHE_COOKIE_TYPE_INDEX,
	82	.get_key = v9fs_cache_session_get_key,
60e78d2c AK	83	};
	84
	85	void v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses)
	86	{
	87	/* If no cache session tag was specified, we generate a random one. */
	88	if (!v9ses->cachetag)
	89	v9fs_random_cachetag(v9ses);
	90
	91	v9ses->fscache = fscache_acquire_cookie(v9fs_cache_netfs.primary_index,
	92	&v9fs_cache_session_index_def,
	93	v9ses);
	94	P9_DPRINTK(P9_DEBUG_FSC, "session %p get cookie %p", v9ses,
	95	v9ses->fscache);
	96	}
	97
	98	void v9fs_cache_session_put_cookie(struct v9fs_session_info *v9ses)
	99	{
	100	P9_DPRINTK(P9_DEBUG_FSC, "session %p put cookie %p", v9ses,
	101	v9ses->fscache);
	102	fscache_relinquish_cookie(v9ses->fscache, 0);
	103	v9ses->fscache = NULL;
	104	}
	105
	106
	107	static uint16_t v9fs_cache_inode_get_key(const void *cookie_netfs_data,
	108	void *buffer, uint16_t bufmax)
	109	{
a78ce05d AK	110	const struct v9fs_inode *v9inode = cookie_netfs_data;
	111	memcpy(buffer, &v9inode->fscache_key->path,
	112	sizeof(v9inode->fscache_key->path));
	113	P9_DPRINTK(P9_DEBUG_FSC, "inode %p get key %llu", &v9inode->vfs_inode,
	114	v9inode->fscache_key->path);
	115	return sizeof(v9inode->fscache_key->path);
60e78d2c AK	116	}
	117
	118	static void v9fs_cache_inode_get_attr(const void *cookie_netfs_data,
	119	uint64_t *size)
	120	{
a78ce05d AK	121	const struct v9fs_inode *v9inode = cookie_netfs_data;
a78ce05d AK	122	*size = i_size_read(&v9inode->vfs_inode);
60e78d2c	123
a78ce05d	124	P9_DPRINTK(P9_DEBUG_FSC, "inode %p get attr %llu", &v9inode->vfs_inode,
60e78d2c AK	125	*size);
	126	}
	127
	128	static uint16_t v9fs_cache_inode_get_aux(const void *cookie_netfs_data,
	129	void *buffer, uint16_t buflen)
	130	{
a78ce05d AK	131	const struct v9fs_inode *v9inode = cookie_netfs_data;
	132	memcpy(buffer, &v9inode->fscache_key->version,
	133	sizeof(v9inode->fscache_key->version));
	134	P9_DPRINTK(P9_DEBUG_FSC, "inode %p get aux %u", &v9inode->vfs_inode,
	135	v9inode->fscache_key->version);
	136	return sizeof(v9inode->fscache_key->version);
60e78d2c AK	137	}
	138
	139	static enum
	140	fscache_checkaux v9fs_cache_inode_check_aux(void *cookie_netfs_data,
	141	const void *buffer,
	142	uint16_t buflen)
	143	{
a78ce05d	144	const struct v9fs_inode *v9inode = cookie_netfs_data;
60e78d2c	145
a78ce05d	146	if (buflen != sizeof(v9inode->fscache_key->version))
60e78d2c AK	147	return FSCACHE_CHECKAUX_OBSOLETE;
60e78d2c AK	148
a78ce05d AK	149	if (memcmp(buffer, &v9inode->fscache_key->version,
a78ce05d AK	150	sizeof(v9inode->fscache_key->version)))
60e78d2c AK	151	return FSCACHE_CHECKAUX_OBSOLETE;
	152
	153	return FSCACHE_CHECKAUX_OKAY;
	154	}
	155
	156	static void v9fs_cache_inode_now_uncached(void *cookie_netfs_data)
	157	{
a78ce05d	158	struct v9fs_inode *v9inode = cookie_netfs_data;
60e78d2c AK	159	struct pagevec pvec;
	160	pgoff_t first;
	161	int loop, nr_pages;
	162
	163	pagevec_init(&pvec, 0);
	164	first = 0;
	165
	166	for (;;) {
a78ce05d	167	nr_pages = pagevec_lookup(&pvec, v9inode->vfs_inode.i_mapping,
60e78d2c AK	168	first,
	169	PAGEVEC_SIZE - pagevec_count(&pvec));
	170	if (!nr_pages)
	171	break;
	172
	173	for (loop = 0; loop < nr_pages; loop++)
	174	ClearPageFsCache(pvec.pages[loop]);
	175
	176	first = pvec.pages[nr_pages - 1]->index + 1;
	177
	178	pvec.nr = nr_pages;
	179	pagevec_release(&pvec);
	180	cond_resched();
	181	}
	182	}
	183
	184	const struct fscache_cookie_def v9fs_cache_inode_index_def = {
	185	.name = "9p.inode",
	186	.type = FSCACHE_COOKIE_TYPE_DATAFILE,
	187	.get_key = v9fs_cache_inode_get_key,
	188	.get_attr = v9fs_cache_inode_get_attr,
	189	.get_aux = v9fs_cache_inode_get_aux,
	190	.check_aux = v9fs_cache_inode_check_aux,
	191	.now_uncached = v9fs_cache_inode_now_uncached,
	192	};
	193
	194	void v9fs_cache_inode_get_cookie(struct inode *inode)
	195	{
a78ce05d	196	struct v9fs_inode *v9inode;
60e78d2c AK	197	struct v9fs_session_info *v9ses;
	198
	199	if (!S_ISREG(inode->i_mode))
	200	return;
	201
a78ce05d AK	202	v9inode = V9FS_I(inode);
a78ce05d AK	203	if (v9inode->fscache)
60e78d2c AK	204	return;
	205
	206	v9ses = v9fs_inode2v9ses(inode);
a78ce05d	207	v9inode->fscache = fscache_acquire_cookie(v9ses->fscache,
60e78d2c	208	&v9fs_cache_inode_index_def,
a78ce05d	209	v9inode);
60e78d2c AK	210
60e78d2c AK	211	P9_DPRINTK(P9_DEBUG_FSC, "inode %p get cookie %p", inode,
a78ce05d	212	v9inode->fscache);
60e78d2c AK	213	}
	214
	215	void v9fs_cache_inode_put_cookie(struct inode *inode)
	216	{
a78ce05d	217	struct v9fs_inode *v9inode = V9FS_I(inode);
60e78d2c	218
a78ce05d	219	if (!v9inode->fscache)
60e78d2c AK	220	return;
60e78d2c AK	221	P9_DPRINTK(P9_DEBUG_FSC, "inode %p put cookie %p", inode,
a78ce05d	222	v9inode->fscache);
60e78d2c	223
a78ce05d AK	224	fscache_relinquish_cookie(v9inode->fscache, 0);
a78ce05d AK	225	v9inode->fscache = NULL;
60e78d2c AK	226	}
	227
	228	void v9fs_cache_inode_flush_cookie(struct inode *inode)
	229	{
a78ce05d	230	struct v9fs_inode *v9inode = V9FS_I(inode);
60e78d2c	231
a78ce05d	232	if (!v9inode->fscache)
60e78d2c AK	233	return;
60e78d2c AK	234	P9_DPRINTK(P9_DEBUG_FSC, "inode %p flush cookie %p", inode,
a78ce05d	235	v9inode->fscache);
60e78d2c	236
a78ce05d AK	237	fscache_relinquish_cookie(v9inode->fscache, 1);
a78ce05d AK	238	v9inode->fscache = NULL;
60e78d2c AK	239	}
	240
	241	void v9fs_cache_inode_set_cookie(struct inode inode, struct file filp)
	242	{
a78ce05d	243	struct v9fs_inode *v9inode = V9FS_I(inode);
60e78d2c AK	244	struct p9_fid *fid;
60e78d2c AK	245
a78ce05d	246	if (!v9inode->fscache)
60e78d2c AK	247	return;
60e78d2c AK	248
a78ce05d	249	spin_lock(&v9inode->fscache_lock);
60e78d2c AK	250	fid = filp->private_data;
	251	if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
	252	v9fs_cache_inode_flush_cookie(inode);
	253	else
	254	v9fs_cache_inode_get_cookie(inode);
	255
a78ce05d	256	spin_unlock(&v9inode->fscache_lock);
60e78d2c AK	257	}
	258
	259	void v9fs_cache_inode_reset_cookie(struct inode *inode)
	260	{
a78ce05d	261	struct v9fs_inode *v9inode = V9FS_I(inode);
60e78d2c AK	262	struct v9fs_session_info *v9ses;
	263	struct fscache_cookie *old;
	264
a78ce05d	265	if (!v9inode->fscache)
60e78d2c AK	266	return;
60e78d2c AK	267
a78ce05d	268	old = v9inode->fscache;
60e78d2c	269
a78ce05d AK	270	spin_lock(&v9inode->fscache_lock);
a78ce05d AK	271	fscache_relinquish_cookie(v9inode->fscache, 1);
60e78d2c AK	272
60e78d2c AK	273	v9ses = v9fs_inode2v9ses(inode);
a78ce05d	274	v9inode->fscache = fscache_acquire_cookie(v9ses->fscache,
60e78d2c	275	&v9fs_cache_inode_index_def,
a78ce05d	276	v9inode);
60e78d2c	277	P9_DPRINTK(P9_DEBUG_FSC, "inode %p revalidating cookie old %p new %p",
a78ce05d	278	inode, old, v9inode->fscache);
60e78d2c	279
a78ce05d	280	spin_unlock(&v9inode->fscache_lock);
60e78d2c AK	281	}
	282
	283	int __v9fs_fscache_release_page(struct page *page, gfp_t gfp)
	284	{
	285	struct inode *inode = page->mapping->host;
a78ce05d	286	struct v9fs_inode *v9inode = V9FS_I(inode);
60e78d2c	287
a78ce05d	288	BUG_ON(!v9inode->fscache);
60e78d2c	289
a78ce05d	290	return fscache_maybe_release_page(v9inode->fscache, page, gfp);
60e78d2c AK	291	}
	292
	293	void __v9fs_fscache_invalidate_page(struct page *page)
	294	{
	295	struct inode *inode = page->mapping->host;
a78ce05d	296	struct v9fs_inode *v9inode = V9FS_I(inode);
60e78d2c	297
a78ce05d	298	BUG_ON(!v9inode->fscache);
60e78d2c AK	299
60e78d2c AK	300	if (PageFsCache(page)) {
a78ce05d	301	fscache_wait_on_page_write(v9inode->fscache, page);
60e78d2c	302	BUG_ON(!PageLocked(page));
a78ce05d	303	fscache_uncache_page(v9inode->fscache, page);
60e78d2c AK	304	}
	305	}
	306
	307	static void v9fs_vfs_readpage_complete(struct page page, void data,
	308	int error)
	309	{
	310	if (!error)
	311	SetPageUptodate(page);
	312
	313	unlock_page(page);
	314	}
	315
	316	/**
	317	* __v9fs_readpage_from_fscache - read a page from cache
	318	*
	319	* Returns 0 if the pages are in cache and a BIO is submitted,
	320	* 1 if the pages are not in cache and -error otherwise.
	321	*/
	322
	323	int __v9fs_readpage_from_fscache(struct inode inode, struct page page)
	324	{
	325	int ret;
a78ce05d	326	const struct v9fs_inode *v9inode = V9FS_I(inode);
60e78d2c AK	327
60e78d2c AK	328	P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
a78ce05d	329	if (!v9inode->fscache)
60e78d2c AK	330	return -ENOBUFS;
60e78d2c AK	331
a78ce05d	332	ret = fscache_read_or_alloc_page(v9inode->fscache,
60e78d2c AK	333	page,
	334	v9fs_vfs_readpage_complete,
	335	NULL,
	336	GFP_KERNEL);
	337	switch (ret) {
	338	case -ENOBUFS:
	339	case -ENODATA:
	340	P9_DPRINTK(P9_DEBUG_FSC, "page/inode not in cache %d", ret);
	341	return 1;
	342	case 0:
	343	P9_DPRINTK(P9_DEBUG_FSC, "BIO submitted");
	344	return ret;
	345	default:
	346	P9_DPRINTK(P9_DEBUG_FSC, "ret %d", ret);
	347	return ret;
	348	}
	349	}
	350
	351	/**
	352	* __v9fs_readpages_from_fscache - read multiple pages from cache
	353	*
	354	* Returns 0 if the pages are in cache and a BIO is submitted,
	355	* 1 if the pages are not in cache and -error otherwise.
	356	*/
	357
	358	int __v9fs_readpages_from_fscache(struct inode *inode,
	359	struct address_space *mapping,
	360	struct list_head *pages,
	361	unsigned *nr_pages)
	362	{
	363	int ret;
a78ce05d	364	const struct v9fs_inode *v9inode = V9FS_I(inode);
60e78d2c AK	365
60e78d2c AK	366	P9_DPRINTK(P9_DEBUG_FSC, "inode %p pages %u", inode, *nr_pages);
a78ce05d	367	if (!v9inode->fscache)
60e78d2c AK	368	return -ENOBUFS;
60e78d2c AK	369
a78ce05d	370	ret = fscache_read_or_alloc_pages(v9inode->fscache,
60e78d2c AK	371	mapping, pages, nr_pages,
	372	v9fs_vfs_readpage_complete,
	373	NULL,
	374	mapping_gfp_mask(mapping));
	375	switch (ret) {
	376	case -ENOBUFS:
	377	case -ENODATA:
	378	P9_DPRINTK(P9_DEBUG_FSC, "pages/inodes not in cache %d", ret);
	379	return 1;
	380	case 0:
	381	BUG_ON(!list_empty(pages));
	382	BUG_ON(*nr_pages != 0);
	383	P9_DPRINTK(P9_DEBUG_FSC, "BIO submitted");
	384	return ret;
	385	default:
	386	P9_DPRINTK(P9_DEBUG_FSC, "ret %d", ret);
	387	return ret;
	388	}
	389	}
	390
	391	/**
	392	* __v9fs_readpage_to_fscache - write a page to the cache
	393	*
	394	*/
	395
	396	void __v9fs_readpage_to_fscache(struct inode inode, struct page page)
	397	{
	398	int ret;
a78ce05d	399	const struct v9fs_inode *v9inode = V9FS_I(inode);
60e78d2c AK	400
60e78d2c AK	401	P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
a78ce05d	402	ret = fscache_write_page(v9inode->fscache, page, GFP_KERNEL);
60e78d2c AK	403	P9_DPRINTK(P9_DEBUG_FSC, "ret = %d", ret);
	404	if (ret != 0)
	405	v9fs_uncache_page(inode, page);
	406	}
2efda799 AK	407
	408	/*
	409	* wait for a page to complete writing to the cache
	410	*/
	411	void __v9fs_fscache_wait_on_page_write(struct inode inode, struct page page)
	412	{
a78ce05d	413	const struct v9fs_inode *v9inode = V9FS_I(inode);
2efda799 AK	414	P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
2efda799 AK	415	if (PageFsCache(page))
a78ce05d	416	fscache_wait_on_page_write(v9inode->fscache, page);
2efda799	417	}