[linux-2.6-block.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/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 kmem_cache *vcookie_cache;

struct fscache_netfs v9fs_cache_netfs = {
	.name 		= "9p",
	.version 	= 0,
};

static void init_once(void *foo)
{
	struct v9fs_cookie *vcookie = (struct v9fs_cookie *) foo;
	vcookie->fscache = NULL;
	vcookie->qid = NULL;
	inode_init_once(&vcookie->inode);
}

/**
 * v9fs_init_vcookiecache - initialize a cache for vcookies to maintain
 *			    vcookie to inode mapping
 *
 * Returns 0 on success.
 */

static int v9fs_init_vcookiecache(void)
{
	vcookie_cache = kmem_cache_create("vcookie_cache",
					  sizeof(struct v9fs_cookie),
					  0, (SLAB_RECLAIM_ACCOUNT|
					      SLAB_MEM_SPREAD),
					  init_once);
	if (!vcookie_cache)
		return -ENOMEM;

	return 0;
}

/**
 * v9fs_destroy_vcookiecache - destroy the cache of vcookies
 *
 */

static void v9fs_destroy_vcookiecache(void)
{
	kmem_cache_destroy(vcookie_cache);
}

int __v9fs_cache_register(void)
{
	int ret;
	ret = v9fs_init_vcookiecache();
	if (ret < 0)
		return ret;

	return fscache_register_netfs(&v9fs_cache_netfs);
}

void __v9fs_cache_unregister(void)
{
	v9fs_destroy_vcookiecache();
	fscache_unregister_netfs(&v9fs_cache_netfs);
}

/**
 * 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_cookie *vcookie = cookie_netfs_data;
	memcpy(buffer, &vcookie->qid->path, sizeof(vcookie->qid->path));

	P9_DPRINTK(P9_DEBUG_FSC, "inode %p get key %llu", &vcookie->inode,
		   vcookie->qid->path);
	return sizeof(vcookie->qid->path);
}

static void v9fs_cache_inode_get_attr(const void *cookie_netfs_data,
				      uint64_t *size)
{
	const struct v9fs_cookie *vcookie = cookie_netfs_data;
	*size = i_size_read(&vcookie->inode);

	P9_DPRINTK(P9_DEBUG_FSC, "inode %p get attr %llu", &vcookie->inode,
		   *size);
}

static uint16_t v9fs_cache_inode_get_aux(const void *cookie_netfs_data,
					 void *buffer, uint16_t buflen)
{
	const struct v9fs_cookie *vcookie = cookie_netfs_data;
	memcpy(buffer, &vcookie->qid->version, sizeof(vcookie->qid->version));

	P9_DPRINTK(P9_DEBUG_FSC, "inode %p get aux %u", &vcookie->inode,
		   vcookie->qid->version);
	return sizeof(vcookie->qid->version);
}

static enum
fscache_checkaux v9fs_cache_inode_check_aux(void *cookie_netfs_data,
					    const void *buffer,
					    uint16_t buflen)
{
	const struct v9fs_cookie *vcookie = cookie_netfs_data;

	if (buflen != sizeof(vcookie->qid->version))
		return FSCACHE_CHECKAUX_OBSOLETE;

	if (memcmp(buffer, &vcookie->qid->version,
		   sizeof(vcookie->qid->version)))
		return FSCACHE_CHECKAUX_OBSOLETE;

	return FSCACHE_CHECKAUX_OKAY;
}

static void v9fs_cache_inode_now_uncached(void *cookie_netfs_data)
{
	struct v9fs_cookie *vcookie = 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, vcookie->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_cookie *vcookie;
	struct v9fs_session_info *v9ses;

	if (!S_ISREG(inode->i_mode))
		return;

	vcookie = v9fs_inode2cookie(inode);
	if (vcookie->fscache)
		return;

	v9ses = v9fs_inode2v9ses(inode);
	vcookie->fscache = fscache_acquire_cookie(v9ses->fscache,
						  &v9fs_cache_inode_index_def,
						  vcookie);

	P9_DPRINTK(P9_DEBUG_FSC, "inode %p get cookie %p", inode,
		   vcookie->fscache);
}

void v9fs_cache_inode_put_cookie(struct inode *inode)
{
	struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);

	if (!vcookie->fscache)
		return;
	P9_DPRINTK(P9_DEBUG_FSC, "inode %p put cookie %p", inode,
		   vcookie->fscache);

	fscache_relinquish_cookie(vcookie->fscache, 0);
	vcookie->fscache = NULL;
}

void v9fs_cache_inode_flush_cookie(struct inode *inode)
{
	struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);

	if (!vcookie->fscache)
		return;
	P9_DPRINTK(P9_DEBUG_FSC, "inode %p flush cookie %p", inode,
		   vcookie->fscache);

	fscache_relinquish_cookie(vcookie->fscache, 1);
	vcookie->fscache = NULL;
}

void v9fs_cache_inode_set_cookie(struct inode *inode, struct file *filp)
{
	struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
	struct p9_fid *fid;

	if (!vcookie->fscache)
		return;

	spin_lock(&vcookie->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(&vcookie->lock);
}

void v9fs_cache_inode_reset_cookie(struct inode *inode)
{
	struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
	struct v9fs_session_info *v9ses;
	struct fscache_cookie *old;

	if (!vcookie->fscache)
		return;

	old = vcookie->fscache;

	spin_lock(&vcookie->lock);
	fscache_relinquish_cookie(vcookie->fscache, 1);

	v9ses = v9fs_inode2v9ses(inode);
	vcookie->fscache = fscache_acquire_cookie(v9ses->fscache,
						  &v9fs_cache_inode_index_def,
						  vcookie);

	P9_DPRINTK(P9_DEBUG_FSC, "inode %p revalidating cookie old %p new %p",
		   inode, old, vcookie->fscache);

	spin_unlock(&vcookie->lock);
}

int __v9fs_fscache_release_page(struct page *page, gfp_t gfp)
{
	struct inode *inode = page->mapping->host;
	struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);

	BUG_ON(!vcookie->fscache);

	if (PageFsCache(page)) {
		if (fscache_check_page_write(vcookie->fscache, page)) {
			if (!(gfp & __GFP_WAIT))
				return 0;
			fscache_wait_on_page_write(vcookie->fscache, page);
		}

		fscache_uncache_page(vcookie->fscache, page);
		ClearPageFsCache(page);
	}

	return 1;
}

void __v9fs_fscache_invalidate_page(struct page *page)
{
	struct inode *inode = page->mapping->host;
	struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);

	BUG_ON(!vcookie->fscache);

	if (PageFsCache(page)) {
		fscache_wait_on_page_write(vcookie->fscache, page);
		BUG_ON(!PageLocked(page));
		fscache_uncache_page(vcookie->fscache, page);
		ClearPageFsCache(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_cookie *vcookie = v9fs_inode2cookie(inode);

	P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
	if (!vcookie->fscache)
		return -ENOBUFS;

	ret = fscache_read_or_alloc_page(vcookie->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_cookie *vcookie = v9fs_inode2cookie(inode);

	P9_DPRINTK(P9_DEBUG_FSC, "inode %p pages %u", inode, *nr_pages);
	if (!vcookie->fscache)
		return -ENOBUFS;

	ret = fscache_read_or_alloc_pages(vcookie->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_cookie *vcookie = v9fs_inode2cookie(inode);

	P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
	ret = fscache_write_page(vcookie->fscache, page, GFP_KERNEL);
	P9_DPRINTK(P9_DEBUG_FSC, "ret =  %d", ret);
	if (ret != 0)
		v9fs_uncache_page(inode, 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>
	25	#include <linux/stat.h>
	26	#include <linux/sched.h>
	27	#include <linux/fs.h>
	28	#include <net/9p/9p.h>
	29
	30	#include "v9fs.h"
	31	#include "cache.h"
	32
	33	#define CACHETAG_LEN 11
	34
	35	struct kmem_cache *vcookie_cache;
	36
	37	struct fscache_netfs v9fs_cache_netfs = {
	38	.name = "9p",
	39	.version = 0,
	40	};
	41
	42	static void init_once(void *foo)
	43	{
	44	struct v9fs_cookie vcookie = (struct v9fs_cookie ) foo;
	45	vcookie->fscache = NULL;
	46	vcookie->qid = NULL;
	47	inode_init_once(&vcookie->inode);
	48	}
	49
	50	/**
	51	* v9fs_init_vcookiecache - initialize a cache for vcookies to maintain
	52	* vcookie to inode mapping
	53	*
	54	* Returns 0 on success.
	55	*/
	56
	57	static int v9fs_init_vcookiecache(void)
	58	{
	59	vcookie_cache = kmem_cache_create("vcookie_cache",
	60	sizeof(struct v9fs_cookie),
	61	0, (SLAB_RECLAIM_ACCOUNT\|
	62	SLAB_MEM_SPREAD),
	63	init_once);
	64	if (!vcookie_cache)
65	return -ENOMEM;
66
67	return 0;
68	}
69
70	/**
71	* v9fs_destroy_vcookiecache - destroy the cache of vcookies
72	*
73	*/
74
75	static void v9fs_destroy_vcookiecache(void)
76	{
77	kmem_cache_destroy(vcookie_cache);
78	}
79
80	int __v9fs_cache_register(void)
81	{
82	int ret;
83	ret = v9fs_init_vcookiecache();
84	if (ret < 0)
85	return ret;
86
87	return fscache_register_netfs(&v9fs_cache_netfs);
88	}
89
90	void __v9fs_cache_unregister(void)
91	{
92	v9fs_destroy_vcookiecache();
93	fscache_unregister_netfs(&v9fs_cache_netfs);
94	}
95
96	/**
97	* v9fs_random_cachetag - Generate a random tag to be associated
98	* with a new cache session.
99	*
100	* The value of jiffies is used for a fairly randomly cache tag.
101	*/
102
103	static
104	int v9fs_random_cachetag(struct v9fs_session_info *v9ses)
105	{
106	v9ses->cachetag = kmalloc(CACHETAG_LEN, GFP_KERNEL);
107	if (!v9ses->cachetag)
108	return -ENOMEM;
109
110	return scnprintf(v9ses->cachetag, CACHETAG_LEN, "%lu", jiffies);
111	}
112
113	static uint16_t v9fs_cache_session_get_key(const void *cookie_netfs_data,
114	void *buffer, uint16_t bufmax)
115	{
116	struct v9fs_session_info *v9ses;
117	uint16_t klen = 0;
118
119	v9ses = (struct v9fs_session_info *)cookie_netfs_data;
120	P9_DPRINTK(P9_DEBUG_FSC, "session %p buf %p size %u", v9ses,
121	buffer, bufmax);
122
123	if (v9ses->cachetag)
124	klen = strlen(v9ses->cachetag);
125
126	if (klen > bufmax)
127	return 0;
128
129	memcpy(buffer, v9ses->cachetag, klen);
130	P9_DPRINTK(P9_DEBUG_FSC, "cache session tag %s", v9ses->cachetag);
131	return klen;
132	}
133
134	const struct fscache_cookie_def v9fs_cache_session_index_def = {
135	.name = "9P.session",
136	.type = FSCACHE_COOKIE_TYPE_INDEX,
137	.get_key = v9fs_cache_session_get_key,
138	};
139
140	void v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses)
141	{
142	/* If no cache session tag was specified, we generate a random one. */
143	if (!v9ses->cachetag)
144	v9fs_random_cachetag(v9ses);
145
146	v9ses->fscache = fscache_acquire_cookie(v9fs_cache_netfs.primary_index,
147	&v9fs_cache_session_index_def,
148	v9ses);
149	P9_DPRINTK(P9_DEBUG_FSC, "session %p get cookie %p", v9ses,
150	v9ses->fscache);
151	}
152
153	void v9fs_cache_session_put_cookie(struct v9fs_session_info *v9ses)
154	{
155	P9_DPRINTK(P9_DEBUG_FSC, "session %p put cookie %p", v9ses,
156	v9ses->fscache);
157	fscache_relinquish_cookie(v9ses->fscache, 0);
158	v9ses->fscache = NULL;
159	}
160
161
162	static uint16_t v9fs_cache_inode_get_key(const void *cookie_netfs_data,
163	void *buffer, uint16_t bufmax)
164	{
165	const struct v9fs_cookie *vcookie = cookie_netfs_data;
166	memcpy(buffer, &vcookie->qid->path, sizeof(vcookie->qid->path));
167
168	P9_DPRINTK(P9_DEBUG_FSC, "inode %p get key %llu", &vcookie->inode,
169	vcookie->qid->path);
170	return sizeof(vcookie->qid->path);
171	}
172
173	static void v9fs_cache_inode_get_attr(const void *cookie_netfs_data,
174	uint64_t *size)
175	{
176	const struct v9fs_cookie *vcookie = cookie_netfs_data;
177	*size = i_size_read(&vcookie->inode);
178
179	P9_DPRINTK(P9_DEBUG_FSC, "inode %p get attr %llu", &vcookie->inode,
180	*size);
181	}
182
183	static uint16_t v9fs_cache_inode_get_aux(const void *cookie_netfs_data,
184	void *buffer, uint16_t buflen)
185	{
186	const struct v9fs_cookie *vcookie = cookie_netfs_data;
187	memcpy(buffer, &vcookie->qid->version, sizeof(vcookie->qid->version));
188
189	P9_DPRINTK(P9_DEBUG_FSC, "inode %p get aux %u", &vcookie->inode,
190	vcookie->qid->version);
191	return sizeof(vcookie->qid->version);
192	}
193
194	static enum
195	fscache_checkaux v9fs_cache_inode_check_aux(void *cookie_netfs_data,
196	const void *buffer,
197	uint16_t buflen)
198	{
199	const struct v9fs_cookie *vcookie = cookie_netfs_data;
200
201	if (buflen != sizeof(vcookie->qid->version))
202	return FSCACHE_CHECKAUX_OBSOLETE;
203
204	if (memcmp(buffer, &vcookie->qid->version,
205	sizeof(vcookie->qid->version)))
206	return FSCACHE_CHECKAUX_OBSOLETE;
207
208	return FSCACHE_CHECKAUX_OKAY;
209	}
210
211	static void v9fs_cache_inode_now_uncached(void *cookie_netfs_data)
212	{
213	struct v9fs_cookie *vcookie = cookie_netfs_data;
214	struct pagevec pvec;
215	pgoff_t first;
216	int loop, nr_pages;
217
218	pagevec_init(&pvec, 0);
219	first = 0;
220
221	for (;;) {
222	nr_pages = pagevec_lookup(&pvec, vcookie->inode.i_mapping,
223	first,
224	PAGEVEC_SIZE - pagevec_count(&pvec));
225	if (!nr_pages)
226	break;
227
228	for (loop = 0; loop < nr_pages; loop++)
229	ClearPageFsCache(pvec.pages[loop]);
230
231	first = pvec.pages[nr_pages - 1]->index + 1;
232
233	pvec.nr = nr_pages;
234	pagevec_release(&pvec);
235	cond_resched();
236	}
237	}
238
239	const struct fscache_cookie_def v9fs_cache_inode_index_def = {
240	.name = "9p.inode",
241	.type = FSCACHE_COOKIE_TYPE_DATAFILE,
242	.get_key = v9fs_cache_inode_get_key,
243	.get_attr = v9fs_cache_inode_get_attr,
244	.get_aux = v9fs_cache_inode_get_aux,
245	.check_aux = v9fs_cache_inode_check_aux,
246	.now_uncached = v9fs_cache_inode_now_uncached,
247	};
248
249	void v9fs_cache_inode_get_cookie(struct inode *inode)
250	{
251	struct v9fs_cookie *vcookie;
252	struct v9fs_session_info *v9ses;
253
254	if (!S_ISREG(inode->i_mode))
255	return;
256
257	vcookie = v9fs_inode2cookie(inode);
258	if (vcookie->fscache)
259	return;
260
261	v9ses = v9fs_inode2v9ses(inode);
262	vcookie->fscache = fscache_acquire_cookie(v9ses->fscache,
263	&v9fs_cache_inode_index_def,
264	vcookie);
265
266	P9_DPRINTK(P9_DEBUG_FSC, "inode %p get cookie %p", inode,
267	vcookie->fscache);
268	}
269
270	void v9fs_cache_inode_put_cookie(struct inode *inode)
271	{
272	struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
273
274	if (!vcookie->fscache)
275	return;
276	P9_DPRINTK(P9_DEBUG_FSC, "inode %p put cookie %p", inode,
277	vcookie->fscache);
278
279	fscache_relinquish_cookie(vcookie->fscache, 0);
280	vcookie->fscache = NULL;
281	}
282
283	void v9fs_cache_inode_flush_cookie(struct inode *inode)
284	{
285	struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
286
287	if (!vcookie->fscache)
288	return;
289	P9_DPRINTK(P9_DEBUG_FSC, "inode %p flush cookie %p", inode,
290	vcookie->fscache);
291
292	fscache_relinquish_cookie(vcookie->fscache, 1);
293	vcookie->fscache = NULL;
294	}
295
296	void v9fs_cache_inode_set_cookie(struct inode inode, struct file filp)
297	{
298	struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
299	struct p9_fid *fid;
300
301	if (!vcookie->fscache)
302	return;
303
304	spin_lock(&vcookie->lock);
305	fid = filp->private_data;
306	if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
307	v9fs_cache_inode_flush_cookie(inode);
308	else
309	v9fs_cache_inode_get_cookie(inode);
310
311	spin_unlock(&vcookie->lock);
312	}
313
314	void v9fs_cache_inode_reset_cookie(struct inode *inode)
315	{
316	struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
317	struct v9fs_session_info *v9ses;
318	struct fscache_cookie *old;
319
320	if (!vcookie->fscache)
321	return;
322
323	old = vcookie->fscache;
324
325	spin_lock(&vcookie->lock);
326	fscache_relinquish_cookie(vcookie->fscache, 1);
327
328	v9ses = v9fs_inode2v9ses(inode);
329	vcookie->fscache = fscache_acquire_cookie(v9ses->fscache,
330	&v9fs_cache_inode_index_def,
331	vcookie);
332
333	P9_DPRINTK(P9_DEBUG_FSC, "inode %p revalidating cookie old %p new %p",
334	inode, old, vcookie->fscache);
335
336	spin_unlock(&vcookie->lock);
337	}
338
339	int __v9fs_fscache_release_page(struct page *page, gfp_t gfp)
340	{
341	struct inode *inode = page->mapping->host;
342	struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
343
344	BUG_ON(!vcookie->fscache);
345
346	if (PageFsCache(page)) {
347	if (fscache_check_page_write(vcookie->fscache, page)) {
348	if (!(gfp & __GFP_WAIT))
349	return 0;
350	fscache_wait_on_page_write(vcookie->fscache, page);
351	}
352
353	fscache_uncache_page(vcookie->fscache, page);
354	ClearPageFsCache(page);
355	}
356
357	return 1;
358	}
359
360	void __v9fs_fscache_invalidate_page(struct page *page)
361	{
362	struct inode *inode = page->mapping->host;
363	struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
364
365	BUG_ON(!vcookie->fscache);
366
367	if (PageFsCache(page)) {
368	fscache_wait_on_page_write(vcookie->fscache, page);
369	BUG_ON(!PageLocked(page));
370	fscache_uncache_page(vcookie->fscache, page);
371	ClearPageFsCache(page);
372	}
373	}
374
375	static void v9fs_vfs_readpage_complete(struct page page, void data,
376	int error)
377	{
378	if (!error)
379	SetPageUptodate(page);
380
381	unlock_page(page);
382	}
383
384	/**
385	* __v9fs_readpage_from_fscache - read a page from cache
386	*
387	* Returns 0 if the pages are in cache and a BIO is submitted,
388	* 1 if the pages are not in cache and -error otherwise.
389	*/
390
391	int __v9fs_readpage_from_fscache(struct inode inode, struct page page)
392	{
393	int ret;
394	const struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
395
396	P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
397	if (!vcookie->fscache)
398	return -ENOBUFS;
399
400	ret = fscache_read_or_alloc_page(vcookie->fscache,
401	page,
402	v9fs_vfs_readpage_complete,
403	NULL,
404	GFP_KERNEL);
405	switch (ret) {
406	case -ENOBUFS:
407	case -ENODATA:
408	P9_DPRINTK(P9_DEBUG_FSC, "page/inode not in cache %d", ret);
409	return 1;
410	case 0:
411	P9_DPRINTK(P9_DEBUG_FSC, "BIO submitted");
412	return ret;
413	default:
414	P9_DPRINTK(P9_DEBUG_FSC, "ret %d", ret);
415	return ret;
416	}
417	}
418
419	/**
420	* __v9fs_readpages_from_fscache - read multiple pages from cache
421	*
422	* Returns 0 if the pages are in cache and a BIO is submitted,
423	* 1 if the pages are not in cache and -error otherwise.
424	*/
425
426	int __v9fs_readpages_from_fscache(struct inode *inode,
427	struct address_space *mapping,
428	struct list_head *pages,
429	unsigned *nr_pages)
430	{
431	int ret;
432	const struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
433
434	P9_DPRINTK(P9_DEBUG_FSC, "inode %p pages %u", inode, *nr_pages);
435	if (!vcookie->fscache)
436	return -ENOBUFS;
437
438	ret = fscache_read_or_alloc_pages(vcookie->fscache,
439	mapping, pages, nr_pages,
440	v9fs_vfs_readpage_complete,
441	NULL,
442	mapping_gfp_mask(mapping));
443	switch (ret) {
444	case -ENOBUFS:
445	case -ENODATA:
446	P9_DPRINTK(P9_DEBUG_FSC, "pages/inodes not in cache %d", ret);
447	return 1;
448	case 0:
449	BUG_ON(!list_empty(pages));
450	BUG_ON(*nr_pages != 0);
451	P9_DPRINTK(P9_DEBUG_FSC, "BIO submitted");
452	return ret;
453	default:
454	P9_DPRINTK(P9_DEBUG_FSC, "ret %d", ret);
455	return ret;
456	}
457	}
458
459	/**
460	* __v9fs_readpage_to_fscache - write a page to the cache
461	*
462	*/
463
464	void __v9fs_readpage_to_fscache(struct inode inode, struct page page)
465	{
466	int ret;
467	const struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
468
469	P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
470	ret = fscache_write_page(vcookie->fscache, page, GFP_KERNEL);
471	P9_DPRINTK(P9_DEBUG_FSC, "ret = %d", ret);
472	if (ret != 0)
473	v9fs_uncache_page(inode, page);
474	}