[net-next-2.6.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 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);

	return fscache_maybe_release_page(vcookie->fscache, page, gfp);
}

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);
	}
}

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>
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
	36	struct kmem_cache *vcookie_cache;
	37
	38	struct fscache_netfs v9fs_cache_netfs = {
	39	.name = "9p",
	40	.version = 0,
	41	};
	42
	43	static void init_once(void *foo)
	44	{
	45	struct v9fs_cookie vcookie = (struct v9fs_cookie ) foo;
	46	vcookie->fscache = NULL;
	47	vcookie->qid = NULL;
	48	inode_init_once(&vcookie->inode);
	49	}
	50
	51	/**
	52	* v9fs_init_vcookiecache - initialize a cache for vcookies to maintain
	53	* vcookie to inode mapping
	54	*
	55	* Returns 0 on success.
	56	*/
	57
	58	static int v9fs_init_vcookiecache(void)
	59	{
	60	vcookie_cache = kmem_cache_create("vcookie_cache",
	61	sizeof(struct v9fs_cookie),
	62	0, (SLAB_RECLAIM_ACCOUNT\|
	63	SLAB_MEM_SPREAD),
	64	init_once);
	65	if (!vcookie_cache)
	66	return -ENOMEM;
	67
	68	return 0;
	69	}
	70
	71	/**
	72	* v9fs_destroy_vcookiecache - destroy the cache of vcookies
	73	*
	74	*/
	75
	76	static void v9fs_destroy_vcookiecache(void)
	77	{
	78	kmem_cache_destroy(vcookie_cache);
	79	}
	80
	81	int __v9fs_cache_register(void)
	82	{
	83	int ret;
	84	ret = v9fs_init_vcookiecache();
	85	if (ret < 0)
	86	return ret;
	87
	88	return fscache_register_netfs(&v9fs_cache_netfs);
	89	}
90
91	void __v9fs_cache_unregister(void)
92	{
93	v9fs_destroy_vcookiecache();
94	fscache_unregister_netfs(&v9fs_cache_netfs);
95	}
96
97	/**
98	* v9fs_random_cachetag - Generate a random tag to be associated
99	* with a new cache session.
100	*
101	* The value of jiffies is used for a fairly randomly cache tag.
102	*/
103
104	static
105	int v9fs_random_cachetag(struct v9fs_session_info *v9ses)
106	{
107	v9ses->cachetag = kmalloc(CACHETAG_LEN, GFP_KERNEL);
108	if (!v9ses->cachetag)
109	return -ENOMEM;
110
111	return scnprintf(v9ses->cachetag, CACHETAG_LEN, "%lu", jiffies);
112	}
113
114	static uint16_t v9fs_cache_session_get_key(const void *cookie_netfs_data,
115	void *buffer, uint16_t bufmax)
116	{
117	struct v9fs_session_info *v9ses;
118	uint16_t klen = 0;
119
120	v9ses = (struct v9fs_session_info *)cookie_netfs_data;
121	P9_DPRINTK(P9_DEBUG_FSC, "session %p buf %p size %u", v9ses,
122	buffer, bufmax);
123
124	if (v9ses->cachetag)
125	klen = strlen(v9ses->cachetag);
126
127	if (klen > bufmax)
128	return 0;
129
130	memcpy(buffer, v9ses->cachetag, klen);
131	P9_DPRINTK(P9_DEBUG_FSC, "cache session tag %s", v9ses->cachetag);
132	return klen;
133	}
134
135	const struct fscache_cookie_def v9fs_cache_session_index_def = {
136	.name = "9P.session",
137	.type = FSCACHE_COOKIE_TYPE_INDEX,
138	.get_key = v9fs_cache_session_get_key,
139	};
140
141	void v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses)
142	{
143	/* If no cache session tag was specified, we generate a random one. */
144	if (!v9ses->cachetag)
145	v9fs_random_cachetag(v9ses);
146
147	v9ses->fscache = fscache_acquire_cookie(v9fs_cache_netfs.primary_index,
148	&v9fs_cache_session_index_def,
149	v9ses);
150	P9_DPRINTK(P9_DEBUG_FSC, "session %p get cookie %p", v9ses,
151	v9ses->fscache);
152	}
153
154	void v9fs_cache_session_put_cookie(struct v9fs_session_info *v9ses)
155	{
156	P9_DPRINTK(P9_DEBUG_FSC, "session %p put cookie %p", v9ses,
157	v9ses->fscache);
158	fscache_relinquish_cookie(v9ses->fscache, 0);
159	v9ses->fscache = NULL;
160	}
161
162
163	static uint16_t v9fs_cache_inode_get_key(const void *cookie_netfs_data,
164	void *buffer, uint16_t bufmax)
165	{
166	const struct v9fs_cookie *vcookie = cookie_netfs_data;
167	memcpy(buffer, &vcookie->qid->path, sizeof(vcookie->qid->path));
168
169	P9_DPRINTK(P9_DEBUG_FSC, "inode %p get key %llu", &vcookie->inode,
170	vcookie->qid->path);
171	return sizeof(vcookie->qid->path);
172	}
173
174	static void v9fs_cache_inode_get_attr(const void *cookie_netfs_data,
175	uint64_t *size)
176	{
177	const struct v9fs_cookie *vcookie = cookie_netfs_data;
178	*size = i_size_read(&vcookie->inode);
179
180	P9_DPRINTK(P9_DEBUG_FSC, "inode %p get attr %llu", &vcookie->inode,
181	*size);
182	}
183
184	static uint16_t v9fs_cache_inode_get_aux(const void *cookie_netfs_data,
185	void *buffer, uint16_t buflen)
186	{
187	const struct v9fs_cookie *vcookie = cookie_netfs_data;
188	memcpy(buffer, &vcookie->qid->version, sizeof(vcookie->qid->version));
189
190	P9_DPRINTK(P9_DEBUG_FSC, "inode %p get aux %u", &vcookie->inode,
191	vcookie->qid->version);
192	return sizeof(vcookie->qid->version);
193	}
194
195	static enum
196	fscache_checkaux v9fs_cache_inode_check_aux(void *cookie_netfs_data,
197	const void *buffer,
198	uint16_t buflen)
199	{
200	const struct v9fs_cookie *vcookie = cookie_netfs_data;
201
202	if (buflen != sizeof(vcookie->qid->version))
203	return FSCACHE_CHECKAUX_OBSOLETE;
204
205	if (memcmp(buffer, &vcookie->qid->version,
206	sizeof(vcookie->qid->version)))
207	return FSCACHE_CHECKAUX_OBSOLETE;
208
209	return FSCACHE_CHECKAUX_OKAY;
210	}
211
212	static void v9fs_cache_inode_now_uncached(void *cookie_netfs_data)
213	{
214	struct v9fs_cookie *vcookie = cookie_netfs_data;
215	struct pagevec pvec;
216	pgoff_t first;
217	int loop, nr_pages;
218
219	pagevec_init(&pvec, 0);
220	first = 0;
221
222	for (;;) {
223	nr_pages = pagevec_lookup(&pvec, vcookie->inode.i_mapping,
224	first,
225	PAGEVEC_SIZE - pagevec_count(&pvec));
226	if (!nr_pages)
227	break;
228
229	for (loop = 0; loop < nr_pages; loop++)
230	ClearPageFsCache(pvec.pages[loop]);
231
232	first = pvec.pages[nr_pages - 1]->index + 1;
233
234	pvec.nr = nr_pages;
235	pagevec_release(&pvec);
236	cond_resched();
237	}
238	}
239
240	const struct fscache_cookie_def v9fs_cache_inode_index_def = {
241	.name = "9p.inode",
242	.type = FSCACHE_COOKIE_TYPE_DATAFILE,
243	.get_key = v9fs_cache_inode_get_key,
244	.get_attr = v9fs_cache_inode_get_attr,
245	.get_aux = v9fs_cache_inode_get_aux,
246	.check_aux = v9fs_cache_inode_check_aux,
247	.now_uncached = v9fs_cache_inode_now_uncached,
248	};
249
250	void v9fs_cache_inode_get_cookie(struct inode *inode)
251	{
252	struct v9fs_cookie *vcookie;
253	struct v9fs_session_info *v9ses;
254
255	if (!S_ISREG(inode->i_mode))
256	return;
257
258	vcookie = v9fs_inode2cookie(inode);
259	if (vcookie->fscache)
260	return;
261
262	v9ses = v9fs_inode2v9ses(inode);
263	vcookie->fscache = fscache_acquire_cookie(v9ses->fscache,
264	&v9fs_cache_inode_index_def,
265	vcookie);
266
267	P9_DPRINTK(P9_DEBUG_FSC, "inode %p get cookie %p", inode,
268	vcookie->fscache);
269	}
270
271	void v9fs_cache_inode_put_cookie(struct inode *inode)
272	{
273	struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
274
275	if (!vcookie->fscache)
276	return;
277	P9_DPRINTK(P9_DEBUG_FSC, "inode %p put cookie %p", inode,
278	vcookie->fscache);
279
280	fscache_relinquish_cookie(vcookie->fscache, 0);
281	vcookie->fscache = NULL;
282	}
283
284	void v9fs_cache_inode_flush_cookie(struct inode *inode)
285	{
286	struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
287
288	if (!vcookie->fscache)
289	return;
290	P9_DPRINTK(P9_DEBUG_FSC, "inode %p flush cookie %p", inode,
291	vcookie->fscache);
292
293	fscache_relinquish_cookie(vcookie->fscache, 1);
294	vcookie->fscache = NULL;
295	}
296
297	void v9fs_cache_inode_set_cookie(struct inode inode, struct file filp)
298	{
299	struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
300	struct p9_fid *fid;
301
302	if (!vcookie->fscache)
303	return;
304
305	spin_lock(&vcookie->lock);
306	fid = filp->private_data;
307	if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
308	v9fs_cache_inode_flush_cookie(inode);
309	else
310	v9fs_cache_inode_get_cookie(inode);
311
312	spin_unlock(&vcookie->lock);
313	}
314
315	void v9fs_cache_inode_reset_cookie(struct inode *inode)
316	{
317	struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
318	struct v9fs_session_info *v9ses;
319	struct fscache_cookie *old;
320
321	if (!vcookie->fscache)
322	return;
323
324	old = vcookie->fscache;
325
326	spin_lock(&vcookie->lock);
327	fscache_relinquish_cookie(vcookie->fscache, 1);
328
329	v9ses = v9fs_inode2v9ses(inode);
330	vcookie->fscache = fscache_acquire_cookie(v9ses->fscache,
331	&v9fs_cache_inode_index_def,
332	vcookie);
333
334	P9_DPRINTK(P9_DEBUG_FSC, "inode %p revalidating cookie old %p new %p",
335	inode, old, vcookie->fscache);
336
337	spin_unlock(&vcookie->lock);
338	}
339
340	int __v9fs_fscache_release_page(struct page *page, gfp_t gfp)
341	{
342	struct inode *inode = page->mapping->host;
343	struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
344
345	BUG_ON(!vcookie->fscache);
346
6f054164	347	return fscache_maybe_release_page(vcookie->fscache, page, gfp);
60e78d2c AK	348	}
	349
	350	void __v9fs_fscache_invalidate_page(struct page *page)
	351	{
	352	struct inode *inode = page->mapping->host;
	353	struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
	354
	355	BUG_ON(!vcookie->fscache);
	356
	357	if (PageFsCache(page)) {
	358	fscache_wait_on_page_write(vcookie->fscache, page);
	359	BUG_ON(!PageLocked(page));
	360	fscache_uncache_page(vcookie->fscache, page);
60e78d2c AK	361	}
	362	}
	363
	364	static void v9fs_vfs_readpage_complete(struct page page, void data,
	365	int error)
	366	{
	367	if (!error)
	368	SetPageUptodate(page);
	369
	370	unlock_page(page);
	371	}
	372
	373	/**
	374	* __v9fs_readpage_from_fscache - read a page from cache
	375	*
	376	* Returns 0 if the pages are in cache and a BIO is submitted,
	377	* 1 if the pages are not in cache and -error otherwise.
	378	*/
	379
	380	int __v9fs_readpage_from_fscache(struct inode inode, struct page page)
	381	{
	382	int ret;
	383	const struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
	384
	385	P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
	386	if (!vcookie->fscache)
	387	return -ENOBUFS;
	388
	389	ret = fscache_read_or_alloc_page(vcookie->fscache,
	390	page,
	391	v9fs_vfs_readpage_complete,
	392	NULL,
	393	GFP_KERNEL);
	394	switch (ret) {
	395	case -ENOBUFS:
	396	case -ENODATA:
	397	P9_DPRINTK(P9_DEBUG_FSC, "page/inode not in cache %d", ret);
	398	return 1;
	399	case 0:
	400	P9_DPRINTK(P9_DEBUG_FSC, "BIO submitted");
	401	return ret;
	402	default:
	403	P9_DPRINTK(P9_DEBUG_FSC, "ret %d", ret);
	404	return ret;
	405	}
	406	}
	407
	408	/**
	409	* __v9fs_readpages_from_fscache - read multiple pages from cache
	410	*
	411	* Returns 0 if the pages are in cache and a BIO is submitted,
	412	* 1 if the pages are not in cache and -error otherwise.
	413	*/
	414
	415	int __v9fs_readpages_from_fscache(struct inode *inode,
	416	struct address_space *mapping,
	417	struct list_head *pages,
	418	unsigned *nr_pages)
	419	{
	420	int ret;
	421	const struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
	422
	423	P9_DPRINTK(P9_DEBUG_FSC, "inode %p pages %u", inode, *nr_pages);
	424	if (!vcookie->fscache)
425	return -ENOBUFS;
426
427	ret = fscache_read_or_alloc_pages(vcookie->fscache,
428	mapping, pages, nr_pages,
429	v9fs_vfs_readpage_complete,
430	NULL,
431	mapping_gfp_mask(mapping));
432	switch (ret) {
433	case -ENOBUFS:
434	case -ENODATA:
435	P9_DPRINTK(P9_DEBUG_FSC, "pages/inodes not in cache %d", ret);
436	return 1;
437	case 0:
438	BUG_ON(!list_empty(pages));
439	BUG_ON(*nr_pages != 0);
440	P9_DPRINTK(P9_DEBUG_FSC, "BIO submitted");
441	return ret;
442	default:
443	P9_DPRINTK(P9_DEBUG_FSC, "ret %d", ret);
444	return ret;
445	}
446	}
447
448	/**
449	* __v9fs_readpage_to_fscache - write a page to the cache
450	*
451	*/
452
453	void __v9fs_readpage_to_fscache(struct inode inode, struct page page)
454	{
455	int ret;
456	const struct v9fs_cookie *vcookie = v9fs_inode2cookie(inode);
457
458	P9_DPRINTK(P9_DEBUG_FSC, "inode %p page %p", inode, page);
459	ret = fscache_write_page(vcookie->fscache, page, GFP_KERNEL);
460	P9_DPRINTK(P9_DEBUG_FSC, "ret = %d", ret);
461	if (ret != 0)
462	v9fs_uncache_page(inode, page);
463	}