[mirror_ubuntu-artful-kernel.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_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, true);
	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 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->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, true);

	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);

	if (!v9inode->fscache)
		return;

	mutex_lock(&v9inode->fscache_lock);

	if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
		v9fs_cache_inode_flush_cookie(inode);
	else
		v9fs_cache_inode_get_cookie(inode);

	mutex_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;

	mutex_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, true);
	p9_debug(P9_DEBUG_FSC, "inode %p revalidating cookie old %p new %p\n",
		 inode, old, v9inode->fscache);

	mutex_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);
}
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;
5d385153 JP	65	p9_debug(P9_DEBUG_FSC, "session %p buf %p size %u\n",
5d385153 JP	66	v9ses, buffer, bufmax);
60e78d2c AK	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);
5d385153	75	p9_debug(P9_DEBUG_FSC, "cache session tag %s\n", v9ses->cachetag);
60e78d2c AK	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,
94d30ae9	93	v9ses, true);
5d385153 JP	94	p9_debug(P9_DEBUG_FSC, "session %p get cookie %p\n",
5d385153 JP	95	v9ses, v9ses->fscache);
60e78d2c AK	96	}
	97
	98	void v9fs_cache_session_put_cookie(struct v9fs_session_info *v9ses)
	99	{
5d385153 JP	100	p9_debug(P9_DEBUG_FSC, "session %p put cookie %p\n",
5d385153 JP	101	v9ses, v9ses->fscache);
60e78d2c AK	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	110	const struct v9fs_inode *v9inode = cookie_netfs_data;
fd2421f5	111	memcpy(buffer, &v9inode->qid.path, sizeof(v9inode->qid.path));
5d385153 JP	112	p9_debug(P9_DEBUG_FSC, "inode %p get key %llu\n",
5d385153 JP	113	&v9inode->vfs_inode, v9inode->qid.path);
fd2421f5	114	return sizeof(v9inode->qid.path);
60e78d2c AK	115	}
	116
	117	static void v9fs_cache_inode_get_attr(const void *cookie_netfs_data,
	118	uint64_t *size)
	119	{
a78ce05d AK	120	const struct v9fs_inode *v9inode = cookie_netfs_data;
a78ce05d AK	121	*size = i_size_read(&v9inode->vfs_inode);
60e78d2c	122
5d385153 JP	123	p9_debug(P9_DEBUG_FSC, "inode %p get attr %llu\n",
5d385153 JP	124	&v9inode->vfs_inode, *size);
60e78d2c AK	125	}
	126
	127	static uint16_t v9fs_cache_inode_get_aux(const void *cookie_netfs_data,
	128	void *buffer, uint16_t buflen)
	129	{
a78ce05d	130	const struct v9fs_inode *v9inode = cookie_netfs_data;
fd2421f5	131	memcpy(buffer, &v9inode->qid.version, sizeof(v9inode->qid.version));
5d385153 JP	132	p9_debug(P9_DEBUG_FSC, "inode %p get aux %u\n",
5d385153 JP	133	&v9inode->vfs_inode, v9inode->qid.version);
fd2421f5	134	return sizeof(v9inode->qid.version);
60e78d2c AK	135	}
	136
	137	static enum
	138	fscache_checkaux v9fs_cache_inode_check_aux(void *cookie_netfs_data,
	139	const void *buffer,
	140	uint16_t buflen)
	141	{
a78ce05d	142	const struct v9fs_inode *v9inode = cookie_netfs_data;
60e78d2c	143
fd2421f5	144	if (buflen != sizeof(v9inode->qid.version))
60e78d2c AK	145	return FSCACHE_CHECKAUX_OBSOLETE;
60e78d2c AK	146
fd2421f5 AK	147	if (memcmp(buffer, &v9inode->qid.version,
fd2421f5 AK	148	sizeof(v9inode->qid.version)))
60e78d2c AK	149	return FSCACHE_CHECKAUX_OBSOLETE;
	150
	151	return FSCACHE_CHECKAUX_OKAY;
	152	}
	153
	154	static void v9fs_cache_inode_now_uncached(void *cookie_netfs_data)
	155	{
a78ce05d	156	struct v9fs_inode *v9inode = cookie_netfs_data;
60e78d2c AK	157	struct pagevec pvec;
	158	pgoff_t first;
	159	int loop, nr_pages;
	160
	161	pagevec_init(&pvec, 0);
	162	first = 0;
	163
	164	for (;;) {
a78ce05d	165	nr_pages = pagevec_lookup(&pvec, v9inode->vfs_inode.i_mapping,
60e78d2c AK	166	first,
	167	PAGEVEC_SIZE - pagevec_count(&pvec));
	168	if (!nr_pages)
	169	break;
	170
	171	for (loop = 0; loop < nr_pages; loop++)
	172	ClearPageFsCache(pvec.pages[loop]);
	173
	174	first = pvec.pages[nr_pages - 1]->index + 1;
	175
	176	pvec.nr = nr_pages;
	177	pagevec_release(&pvec);
	178	cond_resched();
	179	}
	180	}
	181
	182	const struct fscache_cookie_def v9fs_cache_inode_index_def = {
	183	.name = "9p.inode",
	184	.type = FSCACHE_COOKIE_TYPE_DATAFILE,
	185	.get_key = v9fs_cache_inode_get_key,
	186	.get_attr = v9fs_cache_inode_get_attr,
	187	.get_aux = v9fs_cache_inode_get_aux,
	188	.check_aux = v9fs_cache_inode_check_aux,
	189	.now_uncached = v9fs_cache_inode_now_uncached,
	190	};
	191
	192	void v9fs_cache_inode_get_cookie(struct inode *inode)
	193	{
a78ce05d	194	struct v9fs_inode *v9inode;
60e78d2c AK	195	struct v9fs_session_info *v9ses;
	196
	197	if (!S_ISREG(inode->i_mode))
	198	return;
	199
a78ce05d AK	200	v9inode = V9FS_I(inode);
a78ce05d AK	201	if (v9inode->fscache)
60e78d2c AK	202	return;
	203
	204	v9ses = v9fs_inode2v9ses(inode);
a78ce05d	205	v9inode->fscache = fscache_acquire_cookie(v9ses->fscache,
60e78d2c	206	&v9fs_cache_inode_index_def,
94d30ae9	207	v9inode, true);
60e78d2c	208
5d385153 JP	209	p9_debug(P9_DEBUG_FSC, "inode %p get cookie %p\n",
5d385153 JP	210	inode, v9inode->fscache);
60e78d2c AK	211	}
	212
	213	void v9fs_cache_inode_put_cookie(struct inode *inode)
	214	{
a78ce05d	215	struct v9fs_inode *v9inode = V9FS_I(inode);
60e78d2c	216
a78ce05d	217	if (!v9inode->fscache)
60e78d2c	218	return;
5d385153 JP	219	p9_debug(P9_DEBUG_FSC, "inode %p put cookie %p\n",
5d385153 JP	220	inode, v9inode->fscache);
60e78d2c	221
a78ce05d AK	222	fscache_relinquish_cookie(v9inode->fscache, 0);
a78ce05d AK	223	v9inode->fscache = NULL;
60e78d2c AK	224	}
	225
	226	void v9fs_cache_inode_flush_cookie(struct inode *inode)
	227	{
a78ce05d	228	struct v9fs_inode *v9inode = V9FS_I(inode);
60e78d2c	229
a78ce05d	230	if (!v9inode->fscache)
60e78d2c	231	return;
5d385153 JP	232	p9_debug(P9_DEBUG_FSC, "inode %p flush cookie %p\n",
5d385153 JP	233	inode, v9inode->fscache);
60e78d2c	234
a78ce05d AK	235	fscache_relinquish_cookie(v9inode->fscache, 1);
a78ce05d AK	236	v9inode->fscache = NULL;
60e78d2c AK	237	}
	238
	239	void v9fs_cache_inode_set_cookie(struct inode inode, struct file filp)
	240	{
a78ce05d	241	struct v9fs_inode *v9inode = V9FS_I(inode);
60e78d2c	242
a78ce05d	243	if (!v9inode->fscache)
60e78d2c AK	244	return;
60e78d2c AK	245
8f5fed1e	246	mutex_lock(&v9inode->fscache_lock);
bd126e5e	247
60e78d2c AK	248	if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
	249	v9fs_cache_inode_flush_cookie(inode);
	250	else
	251	v9fs_cache_inode_get_cookie(inode);
	252
8f5fed1e	253	mutex_unlock(&v9inode->fscache_lock);
60e78d2c AK	254	}
	255
	256	void v9fs_cache_inode_reset_cookie(struct inode *inode)
	257	{
a78ce05d	258	struct v9fs_inode *v9inode = V9FS_I(inode);
60e78d2c AK	259	struct v9fs_session_info *v9ses;
	260	struct fscache_cookie *old;
	261
a78ce05d	262	if (!v9inode->fscache)
60e78d2c AK	263	return;
60e78d2c AK	264
a78ce05d	265	old = v9inode->fscache;
60e78d2c	266
8f5fed1e	267	mutex_lock(&v9inode->fscache_lock);
a78ce05d	268	fscache_relinquish_cookie(v9inode->fscache, 1);
60e78d2c AK	269
60e78d2c AK	270	v9ses = v9fs_inode2v9ses(inode);
a78ce05d	271	v9inode->fscache = fscache_acquire_cookie(v9ses->fscache,
60e78d2c	272	&v9fs_cache_inode_index_def,
94d30ae9	273	v9inode, true);
5d385153 JP	274	p9_debug(P9_DEBUG_FSC, "inode %p revalidating cookie old %p new %p\n",
5d385153 JP	275	inode, old, v9inode->fscache);
60e78d2c	276
8f5fed1e	277	mutex_unlock(&v9inode->fscache_lock);
60e78d2c AK	278	}
	279
	280	int __v9fs_fscache_release_page(struct page *page, gfp_t gfp)
	281	{
	282	struct inode *inode = page->mapping->host;
a78ce05d	283	struct v9fs_inode *v9inode = V9FS_I(inode);
60e78d2c	284
a78ce05d	285	BUG_ON(!v9inode->fscache);
60e78d2c	286
a78ce05d	287	return fscache_maybe_release_page(v9inode->fscache, page, gfp);
60e78d2c AK	288	}
	289
	290	void __v9fs_fscache_invalidate_page(struct page *page)
	291	{
	292	struct inode *inode = page->mapping->host;
a78ce05d	293	struct v9fs_inode *v9inode = V9FS_I(inode);
60e78d2c	294
a78ce05d	295	BUG_ON(!v9inode->fscache);
60e78d2c AK	296
60e78d2c AK	297	if (PageFsCache(page)) {
a78ce05d	298	fscache_wait_on_page_write(v9inode->fscache, page);
60e78d2c	299	BUG_ON(!PageLocked(page));
a78ce05d	300	fscache_uncache_page(v9inode->fscache, page);
60e78d2c AK	301	}
	302	}
	303
	304	static void v9fs_vfs_readpage_complete(struct page page, void data,
	305	int error)
	306	{
	307	if (!error)
	308	SetPageUptodate(page);
	309
	310	unlock_page(page);
	311	}
	312
	313	/**
	314	* __v9fs_readpage_from_fscache - read a page from cache
	315	*
	316	* Returns 0 if the pages are in cache and a BIO is submitted,
	317	* 1 if the pages are not in cache and -error otherwise.
	318	*/
	319
	320	int __v9fs_readpage_from_fscache(struct inode inode, struct page page)
	321	{
	322	int ret;
a78ce05d	323	const struct v9fs_inode *v9inode = V9FS_I(inode);
60e78d2c	324
5d385153	325	p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page);
a78ce05d	326	if (!v9inode->fscache)
60e78d2c AK	327	return -ENOBUFS;
60e78d2c AK	328
a78ce05d	329	ret = fscache_read_or_alloc_page(v9inode->fscache,
60e78d2c AK	330	page,
	331	v9fs_vfs_readpage_complete,
	332	NULL,
	333	GFP_KERNEL);
	334	switch (ret) {
	335	case -ENOBUFS:
	336	case -ENODATA:
5d385153	337	p9_debug(P9_DEBUG_FSC, "page/inode not in cache %d\n", ret);
60e78d2c AK	338	return 1;
60e78d2c AK	339	case 0:
5d385153	340	p9_debug(P9_DEBUG_FSC, "BIO submitted\n");
60e78d2c AK	341	return ret;
60e78d2c AK	342	default:
5d385153	343	p9_debug(P9_DEBUG_FSC, "ret %d\n", ret);
60e78d2c AK	344	return ret;
	345	}
	346	}
	347
	348	/**
	349	* __v9fs_readpages_from_fscache - read multiple pages from cache
	350	*
	351	* Returns 0 if the pages are in cache and a BIO is submitted,
	352	* 1 if the pages are not in cache and -error otherwise.
	353	*/
	354
	355	int __v9fs_readpages_from_fscache(struct inode *inode,
	356	struct address_space *mapping,
	357	struct list_head *pages,
	358	unsigned *nr_pages)
	359	{
	360	int ret;
a78ce05d	361	const struct v9fs_inode *v9inode = V9FS_I(inode);
60e78d2c	362
5d385153	363	p9_debug(P9_DEBUG_FSC, "inode %p pages %u\n", inode, *nr_pages);
a78ce05d	364	if (!v9inode->fscache)
60e78d2c AK	365	return -ENOBUFS;
60e78d2c AK	366
a78ce05d	367	ret = fscache_read_or_alloc_pages(v9inode->fscache,
60e78d2c AK	368	mapping, pages, nr_pages,
	369	v9fs_vfs_readpage_complete,
	370	NULL,
	371	mapping_gfp_mask(mapping));
	372	switch (ret) {
	373	case -ENOBUFS:
	374	case -ENODATA:
5d385153	375	p9_debug(P9_DEBUG_FSC, "pages/inodes not in cache %d\n", ret);
60e78d2c AK	376	return 1;
	377	case 0:
	378	BUG_ON(!list_empty(pages));
	379	BUG_ON(*nr_pages != 0);
5d385153	380	p9_debug(P9_DEBUG_FSC, "BIO submitted\n");
60e78d2c AK	381	return ret;
60e78d2c AK	382	default:
5d385153	383	p9_debug(P9_DEBUG_FSC, "ret %d\n", ret);
60e78d2c AK	384	return ret;
	385	}
	386	}
	387
	388	/**
	389	* __v9fs_readpage_to_fscache - write a page to the cache
	390	*
	391	*/
	392
	393	void __v9fs_readpage_to_fscache(struct inode inode, struct page page)
	394	{
	395	int ret;
a78ce05d	396	const struct v9fs_inode *v9inode = V9FS_I(inode);
60e78d2c	397
5d385153	398	p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page);
a78ce05d	399	ret = fscache_write_page(v9inode->fscache, page, GFP_KERNEL);
5d385153	400	p9_debug(P9_DEBUG_FSC, "ret = %d\n", ret);
60e78d2c AK	401	if (ret != 0)
	402	v9fs_uncache_page(inode, page);
	403	}
2efda799 AK	404
	405	/*
	406	* wait for a page to complete writing to the cache
	407	*/
	408	void __v9fs_fscache_wait_on_page_write(struct inode inode, struct page page)
	409	{
a78ce05d	410	const struct v9fs_inode *v9inode = V9FS_I(inode);
5d385153	411	p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page);
2efda799	412	if (PageFsCache(page))
a78ce05d	413	fscache_wait_on_page_write(v9inode->fscache, page);
2efda799	414	}