[mirror_ubuntu-zesty-kernel.git] / fs / ceph / cache.c

/*
 * Ceph cache definitions.
 *
 *  Copyright (C) 2013 by Adfin Solutions, Inc. All Rights Reserved.
 *  Written by Milosz Tanski (milosz@adfin.com)
 *
 *  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 "super.h"
#include "cache.h"

struct ceph_aux_inode {
	u64 		version;
	struct timespec	mtime;
	loff_t          size;
};

struct fscache_netfs ceph_cache_netfs = {
	.name		= "ceph",
	.version	= 0,
};

static uint16_t ceph_fscache_session_get_key(const void *cookie_netfs_data,
					     void *buffer, uint16_t maxbuf)
{
	const struct ceph_fs_client* fsc = cookie_netfs_data;
	uint16_t klen;

	klen = sizeof(fsc->client->fsid);
	if (klen > maxbuf)
		return 0;

	memcpy(buffer, &fsc->client->fsid, klen);
	return klen;
}

static const struct fscache_cookie_def ceph_fscache_fsid_object_def = {
	.name		= "CEPH.fsid",
	.type		= FSCACHE_COOKIE_TYPE_INDEX,
	.get_key	= ceph_fscache_session_get_key,
};

int ceph_fscache_register(void)
{
	return fscache_register_netfs(&ceph_cache_netfs);
}

void ceph_fscache_unregister(void)
{
	fscache_unregister_netfs(&ceph_cache_netfs);
}

int ceph_fscache_register_fs(struct ceph_fs_client* fsc)
{
	fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index,
					      &ceph_fscache_fsid_object_def,
					      fsc, true);
	if (!fsc->fscache)
		pr_err("Unable to register fsid: %p fscache cookie\n", fsc);

	return 0;
}

static uint16_t ceph_fscache_inode_get_key(const void *cookie_netfs_data,
					   void *buffer, uint16_t maxbuf)
{
	const struct ceph_inode_info* ci = cookie_netfs_data;
	uint16_t klen;

	/* use ceph virtual inode (id + snapshot) */
	klen = sizeof(ci->i_vino);
	if (klen > maxbuf)
		return 0;

	memcpy(buffer, &ci->i_vino, klen);
	return klen;
}

static uint16_t ceph_fscache_inode_get_aux(const void *cookie_netfs_data,
					   void *buffer, uint16_t bufmax)
{
	struct ceph_aux_inode aux;
	const struct ceph_inode_info* ci = cookie_netfs_data;
	const struct inode* inode = &ci->vfs_inode;

	memset(&aux, 0, sizeof(aux));
	aux.version = ci->i_version;
	aux.mtime = inode->i_mtime;
	aux.size = i_size_read(inode);

	memcpy(buffer, &aux, sizeof(aux));

	return sizeof(aux);
}

static void ceph_fscache_inode_get_attr(const void *cookie_netfs_data,
					uint64_t *size)
{
	const struct ceph_inode_info* ci = cookie_netfs_data;
	*size = i_size_read(&ci->vfs_inode);
}

static enum fscache_checkaux ceph_fscache_inode_check_aux(
	void *cookie_netfs_data, const void *data, uint16_t dlen)
{
	struct ceph_aux_inode aux;
	struct ceph_inode_info* ci = cookie_netfs_data;
	struct inode* inode = &ci->vfs_inode;

	if (dlen != sizeof(aux))
		return FSCACHE_CHECKAUX_OBSOLETE;

	memset(&aux, 0, sizeof(aux));
	aux.version = ci->i_version;
	aux.mtime = inode->i_mtime;
	aux.size = i_size_read(inode);

	if (memcmp(data, &aux, sizeof(aux)) != 0)
		return FSCACHE_CHECKAUX_OBSOLETE;

	dout("ceph inode 0x%p cached okay", ci);
	return FSCACHE_CHECKAUX_OKAY;
}

static void ceph_fscache_inode_now_uncached(void* cookie_netfs_data)
{
	struct ceph_inode_info* ci = cookie_netfs_data;
	struct pagevec pvec;
	pgoff_t first;
	int loop, nr_pages;

	pagevec_init(&pvec, 0);
	first = 0;

	dout("ceph inode 0x%p now uncached", ci);

	while (1) {
		nr_pages = pagevec_lookup(&pvec, ci->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();
	}
}

static const struct fscache_cookie_def ceph_fscache_inode_object_def = {
	.name		= "CEPH.inode",
	.type		= FSCACHE_COOKIE_TYPE_DATAFILE,
	.get_key	= ceph_fscache_inode_get_key,
	.get_attr	= ceph_fscache_inode_get_attr,
	.get_aux	= ceph_fscache_inode_get_aux,
	.check_aux	= ceph_fscache_inode_check_aux,
	.now_uncached	= ceph_fscache_inode_now_uncached,
};

void ceph_fscache_register_inode_cookie(struct inode *inode)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);

	/* No caching for filesystem */
	if (fsc->fscache == NULL)
		return;

	/* Only cache for regular files that are read only */
	if (!S_ISREG(inode->i_mode))
		return;

	inode_lock_nested(inode, I_MUTEX_CHILD);
	if (!ci->fscache) {
		ci->fscache = fscache_acquire_cookie(fsc->fscache,
					&ceph_fscache_inode_object_def,
					ci, false);
	}
	inode_unlock(inode);
}

void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
{
	struct fscache_cookie* cookie;

	if ((cookie = ci->fscache) == NULL)
		return;

	ci->fscache = NULL;

	fscache_uncache_all_inode_pages(cookie, &ci->vfs_inode);
	fscache_relinquish_cookie(cookie, 0);
}

static bool ceph_fscache_can_enable(void *data)
{
	struct inode *inode = data;
	return !inode_is_open_for_write(inode);
}

void ceph_fscache_file_set_cookie(struct inode *inode, struct file *filp)
{
	struct ceph_inode_info *ci = ceph_inode(inode);

	if (!fscache_cookie_valid(ci->fscache))
		return;

	if (inode_is_open_for_write(inode)) {
		dout("fscache_file_set_cookie %p %p disabling cache\n",
		     inode, filp);
		fscache_disable_cookie(ci->fscache, false);
		fscache_uncache_all_inode_pages(ci->fscache, inode);
	} else {
		fscache_enable_cookie(ci->fscache, ceph_fscache_can_enable,
				inode);
		if (fscache_cookie_enabled(ci->fscache)) {
			dout("fscache_file_set_cookie %p %p enabing cache\n",
			     inode, filp);
		}
	}
}

static void ceph_vfs_readpage_complete(struct page *page, void *data, int error)
{
	if (!error)
		SetPageUptodate(page);
}

static void ceph_vfs_readpage_complete_unlock(struct page *page, void *data, int error)
{
	if (!error)
		SetPageUptodate(page);

	unlock_page(page);
}

static inline bool cache_valid(struct ceph_inode_info *ci)
{
	return ci->i_fscache_gen == ci->i_rdcache_gen;
}


/* Atempt to read from the fscache,
 *
 * This function is called from the readpage_nounlock context. DO NOT attempt to
 * unlock the page here (or in the callback).
 */
int ceph_readpage_from_fscache(struct inode *inode, struct page *page)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
	int ret;

	if (!cache_valid(ci))
		return -ENOBUFS;

	ret = fscache_read_or_alloc_page(ci->fscache, page,
					 ceph_vfs_readpage_complete, NULL,
					 GFP_KERNEL);

	switch (ret) {
		case 0: /* Page found */
			dout("page read submitted\n");
			return 0;
		case -ENOBUFS: /* Pages were not found, and can't be */
		case -ENODATA: /* Pages were not found */
			dout("page/inode not in cache\n");
			return ret;
		default:
			dout("%s: unknown error ret = %i\n", __func__, ret);
			return ret;
	}
}

int ceph_readpages_from_fscache(struct inode *inode,
				  struct address_space *mapping,
				  struct list_head *pages,
				  unsigned *nr_pages)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
	int ret;

	if (!cache_valid(ci))
		return -ENOBUFS;

	ret = fscache_read_or_alloc_pages(ci->fscache, mapping, pages, nr_pages,
					  ceph_vfs_readpage_complete_unlock,
					  NULL, mapping_gfp_mask(mapping));

	switch (ret) {
		case 0: /* All pages found */
			dout("all-page read submitted\n");
			return 0;
		case -ENOBUFS: /* Some pages were not found, and can't be */
		case -ENODATA: /* some pages were not found */
			dout("page/inode not in cache\n");
			return ret;
		default:
			dout("%s: unknown error ret = %i\n", __func__, ret);
			return ret;
	}
}

void ceph_readpage_to_fscache(struct inode *inode, struct page *page)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
	int ret;

	if (!PageFsCache(page))
		return;

	if (!cache_valid(ci))
		return;

	ret = fscache_write_page(ci->fscache, page, GFP_KERNEL);
	if (ret)
		 fscache_uncache_page(ci->fscache, page);
}

void ceph_invalidate_fscache_page(struct inode* inode, struct page *page)
{
	struct ceph_inode_info *ci = ceph_inode(inode);

	if (!PageFsCache(page))
		return;

	fscache_wait_on_page_write(ci->fscache, page);
	fscache_uncache_page(ci->fscache, page);
}

void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
{
	fscache_relinquish_cookie(fsc->fscache, 0);
	fsc->fscache = NULL;
}

/*
 * caller should hold CEPH_CAP_FILE_{RD,CACHE}
 */
void ceph_fscache_revalidate_cookie(struct ceph_inode_info *ci)
{
	if (cache_valid(ci))
		return;

	/* resue i_truncate_mutex. There should be no pending
	 * truncate while the caller holds CEPH_CAP_FILE_RD */
	mutex_lock(&ci->i_truncate_mutex);
	if (!cache_valid(ci)) {
		if (fscache_check_consistency(ci->fscache))
			fscache_invalidate(ci->fscache);
		spin_lock(&ci->i_ceph_lock);
		ci->i_fscache_gen = ci->i_rdcache_gen;
		spin_unlock(&ci->i_ceph_lock);
	}
	mutex_unlock(&ci->i_truncate_mutex);
}
Commit	Line	Data
99ccbd22 MT	1	/*
	2	* Ceph cache definitions.
	3	*
	4	* Copyright (C) 2013 by Adfin Solutions, Inc. All Rights Reserved.
	5	* Written by Milosz Tanski (milosz@adfin.com)
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2
	9	* as published by the Free Software Foundation.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program; if not, write to:
	18	* Free Software Foundation
	19	* 51 Franklin Street, Fifth Floor
	20	* Boston, MA 02111-1301 USA
	21	*
	22	*/
	23
99ccbd22 MT	24	#include "super.h"
	25	#include "cache.h"
	26
	27	struct ceph_aux_inode {
f6973c09	28	u64 version;
99ccbd22 MT	29	struct timespec mtime;
	30	loff_t size;
	31	};
	32
	33	struct fscache_netfs ceph_cache_netfs = {
	34	.name = "ceph",
	35	.version = 0,
	36	};
	37
	38	static uint16_t ceph_fscache_session_get_key(const void *cookie_netfs_data,
	39	void *buffer, uint16_t maxbuf)
	40	{
	41	const struct ceph_fs_client* fsc = cookie_netfs_data;
	42	uint16_t klen;
	43
	44	klen = sizeof(fsc->client->fsid);
	45	if (klen > maxbuf)
	46	return 0;
	47
	48	memcpy(buffer, &fsc->client->fsid, klen);
	49	return klen;
	50	}
	51
	52	static const struct fscache_cookie_def ceph_fscache_fsid_object_def = {
	53	.name = "CEPH.fsid",
	54	.type = FSCACHE_COOKIE_TYPE_INDEX,
	55	.get_key = ceph_fscache_session_get_key,
	56	};
	57
971f0bde	58	int ceph_fscache_register(void)
99ccbd22 MT	59	{
	60	return fscache_register_netfs(&ceph_cache_netfs);
	61	}
	62
971f0bde	63	void ceph_fscache_unregister(void)
99ccbd22 MT	64	{
	65	fscache_unregister_netfs(&ceph_cache_netfs);
	66	}
	67
	68	int ceph_fscache_register_fs(struct ceph_fs_client* fsc)
	69	{
	70	fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index,
	71	&ceph_fscache_fsid_object_def,
94d30ae9	72	fsc, true);
f7f7e7a0	73	if (!fsc->fscache)
679f0b82	74	pr_err("Unable to register fsid: %p fscache cookie\n", fsc);
99ccbd22 MT	75
	76	return 0;
	77	}
	78
	79	static uint16_t ceph_fscache_inode_get_key(const void *cookie_netfs_data,
	80	void *buffer, uint16_t maxbuf)
	81	{
	82	const struct ceph_inode_info* ci = cookie_netfs_data;
	83	uint16_t klen;
	84
1291fb95	85	/* use ceph virtual inode (id + snapshot) */
99ccbd22 MT	86	klen = sizeof(ci->i_vino);
	87	if (klen > maxbuf)
	88	return 0;
	89
	90	memcpy(buffer, &ci->i_vino, klen);
	91	return klen;
	92	}
	93
	94	static uint16_t ceph_fscache_inode_get_aux(const void *cookie_netfs_data,
	95	void *buffer, uint16_t bufmax)
	96	{
	97	struct ceph_aux_inode aux;
	98	const struct ceph_inode_info* ci = cookie_netfs_data;
	99	const struct inode* inode = &ci->vfs_inode;
	100
	101	memset(&aux, 0, sizeof(aux));
f6973c09	102	aux.version = ci->i_version;
99ccbd22	103	aux.mtime = inode->i_mtime;
99c88e69	104	aux.size = i_size_read(inode);
99ccbd22 MT	105
	106	memcpy(buffer, &aux, sizeof(aux));
	107
	108	return sizeof(aux);
	109	}
	110
	111	static void ceph_fscache_inode_get_attr(const void *cookie_netfs_data,
	112	uint64_t *size)
	113	{
	114	const struct ceph_inode_info* ci = cookie_netfs_data;
99c88e69	115	*size = i_size_read(&ci->vfs_inode);
99ccbd22 MT	116	}
	117
	118	static enum fscache_checkaux ceph_fscache_inode_check_aux(
	119	void cookie_netfs_data, const void data, uint16_t dlen)
	120	{
	121	struct ceph_aux_inode aux;
	122	struct ceph_inode_info* ci = cookie_netfs_data;
	123	struct inode* inode = &ci->vfs_inode;
	124
	125	if (dlen != sizeof(aux))
	126	return FSCACHE_CHECKAUX_OBSOLETE;
	127
	128	memset(&aux, 0, sizeof(aux));
f6973c09	129	aux.version = ci->i_version;
99ccbd22	130	aux.mtime = inode->i_mtime;
99c88e69	131	aux.size = i_size_read(inode);
99ccbd22 MT	132
	133	if (memcmp(data, &aux, sizeof(aux)) != 0)
	134	return FSCACHE_CHECKAUX_OBSOLETE;
	135
	136	dout("ceph inode 0x%p cached okay", ci);
	137	return FSCACHE_CHECKAUX_OKAY;
	138	}
	139
	140	static void ceph_fscache_inode_now_uncached(void* cookie_netfs_data)
	141	{
	142	struct ceph_inode_info* ci = cookie_netfs_data;
	143	struct pagevec pvec;
	144	pgoff_t first;
	145	int loop, nr_pages;
	146
	147	pagevec_init(&pvec, 0);
	148	first = 0;
	149
	150	dout("ceph inode 0x%p now uncached", ci);
	151
	152	while (1) {
	153	nr_pages = pagevec_lookup(&pvec, ci->vfs_inode.i_mapping, first,
	154	PAGEVEC_SIZE - pagevec_count(&pvec));
	155
	156	if (!nr_pages)
	157	break;
	158
	159	for (loop = 0; loop < nr_pages; loop++)
	160	ClearPageFsCache(pvec.pages[loop]);
	161
	162	first = pvec.pages[nr_pages - 1]->index + 1;
	163
	164	pvec.nr = nr_pages;
	165	pagevec_release(&pvec);
	166	cond_resched();
	167	}
	168	}
	169
	170	static const struct fscache_cookie_def ceph_fscache_inode_object_def = {
	171	.name = "CEPH.inode",
	172	.type = FSCACHE_COOKIE_TYPE_DATAFILE,
	173	.get_key = ceph_fscache_inode_get_key,
	174	.get_attr = ceph_fscache_inode_get_attr,
	175	.get_aux = ceph_fscache_inode_get_aux,
	176	.check_aux = ceph_fscache_inode_check_aux,
	177	.now_uncached = ceph_fscache_inode_now_uncached,
	178	};
	179
46b59b2b	180	void ceph_fscache_register_inode_cookie(struct inode *inode)
99ccbd22	181	{
46b59b2b YZ	182	struct ceph_inode_info *ci = ceph_inode(inode);
46b59b2b YZ	183	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
99ccbd22 MT	184
	185	/* No caching for filesystem */
	186	if (fsc->fscache == NULL)
	187	return;
	188
	189	/* Only cache for regular files that are read only */
46b59b2b	190	if (!S_ISREG(inode->i_mode))
99ccbd22 MT	191	return;
99ccbd22 MT	192
46b59b2b YZ	193	inode_lock_nested(inode, I_MUTEX_CHILD);
	194	if (!ci->fscache) {
	195	ci->fscache = fscache_acquire_cookie(fsc->fscache,
	196	&ceph_fscache_inode_object_def,
	197	ci, false);
	198	}
5955102c	199	inode_unlock(inode);
99ccbd22 MT	200	}
	201
	202	void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
	203	{
	204	struct fscache_cookie* cookie;
	205
	206	if ((cookie = ci->fscache) == NULL)
	207	return;
	208
	209	ci->fscache = NULL;
	210
	211	fscache_uncache_all_inode_pages(cookie, &ci->vfs_inode);
	212	fscache_relinquish_cookie(cookie, 0);
	213	}
	214
46b59b2b YZ	215	static bool ceph_fscache_can_enable(void *data)
	216	{
	217	struct inode *inode = data;
	218	return !inode_is_open_for_write(inode);
	219	}
	220
	221	void ceph_fscache_file_set_cookie(struct inode inode, struct file filp)
	222	{
	223	struct ceph_inode_info *ci = ceph_inode(inode);
	224
	225	if (!fscache_cookie_valid(ci->fscache))
	226	return;
	227
	228	if (inode_is_open_for_write(inode)) {
	229	dout("fscache_file_set_cookie %p %p disabling cache\n",
	230	inode, filp);
	231	fscache_disable_cookie(ci->fscache, false);
	232	fscache_uncache_all_inode_pages(ci->fscache, inode);
	233	} else {
	234	fscache_enable_cookie(ci->fscache, ceph_fscache_can_enable,
	235	inode);
	236	if (fscache_cookie_enabled(ci->fscache)) {
	237	dout("fscache_file_set_cookie %p %p enabing cache\n",
	238	inode, filp);
	239	}
	240	}
	241	}
	242
99ccbd22 MT	243	static void ceph_vfs_readpage_complete(struct page page, void data, int error)
	244	{
	245	if (!error)
	246	SetPageUptodate(page);
	247	}
	248
	249	static void ceph_vfs_readpage_complete_unlock(struct page page, void data, int error)
	250	{
	251	if (!error)
	252	SetPageUptodate(page);
	253
	254	unlock_page(page);
	255	}
	256
3b33f692	257	static inline bool cache_valid(struct ceph_inode_info *ci)
99ccbd22	258	{
f7f7e7a0	259	return ci->i_fscache_gen == ci->i_rdcache_gen;
99ccbd22 MT	260	}
	261
	262
	263	/* Atempt to read from the fscache,
	264	*
	265	* This function is called from the readpage_nounlock context. DO NOT attempt to
	266	* unlock the page here (or in the callback).
	267	*/
	268	int ceph_readpage_from_fscache(struct inode inode, struct page page)
	269	{
	270	struct ceph_inode_info *ci = ceph_inode(inode);
	271	int ret;
	272
	273	if (!cache_valid(ci))
	274	return -ENOBUFS;
	275
	276	ret = fscache_read_or_alloc_page(ci->fscache, page,
	277	ceph_vfs_readpage_complete, NULL,
	278	GFP_KERNEL);
	279
	280	switch (ret) {
	281	case 0: /* Page found */
	282	dout("page read submitted\n");
	283	return 0;
	284	case -ENOBUFS: /* Pages were not found, and can't be */
	285	case -ENODATA: /* Pages were not found */
	286	dout("page/inode not in cache\n");
	287	return ret;
	288	default:
	289	dout("%s: unknown error ret = %i\n", __func__, ret);
	290	return ret;
	291	}
	292	}
	293
	294	int ceph_readpages_from_fscache(struct inode *inode,
	295	struct address_space *mapping,
	296	struct list_head *pages,
	297	unsigned *nr_pages)
	298	{
	299	struct ceph_inode_info *ci = ceph_inode(inode);
	300	int ret;
	301
	302	if (!cache_valid(ci))
	303	return -ENOBUFS;
	304
	305	ret = fscache_read_or_alloc_pages(ci->fscache, mapping, pages, nr_pages,
	306	ceph_vfs_readpage_complete_unlock,
	307	NULL, mapping_gfp_mask(mapping));
	308
	309	switch (ret) {
	310	case 0: /* All pages found */
	311	dout("all-page read submitted\n");
	312	return 0;
	313	case -ENOBUFS: /* Some pages were not found, and can't be */
	314	case -ENODATA: /* some pages were not found */
	315	dout("page/inode not in cache\n");
	316	return ret;
	317	default:
	318	dout("%s: unknown error ret = %i\n", __func__, ret);
	319	return ret;
	320	}
	321	}
	322
	323	void ceph_readpage_to_fscache(struct inode inode, struct page page)
324	{
325	struct ceph_inode_info *ci = ceph_inode(inode);
326	int ret;
327
9b8dd1e8 MT	328	if (!PageFsCache(page))
	329	return;
	330
99ccbd22 MT	331	if (!cache_valid(ci))
	332	return;
	333
	334	ret = fscache_write_page(ci->fscache, page, GFP_KERNEL);
	335	if (ret)
	336	fscache_uncache_page(ci->fscache, page);
	337	}
	338
	339	void ceph_invalidate_fscache_page(struct inode* inode, struct page *page)
	340	{
	341	struct ceph_inode_info *ci = ceph_inode(inode);
	342
ffc79664 MT	343	if (!PageFsCache(page))
	344	return;
	345
99ccbd22 MT	346	fscache_wait_on_page_write(ci->fscache, page);
	347	fscache_uncache_page(ci->fscache, page);
	348	}
	349
	350	void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
	351	{
99ccbd22 MT	352	fscache_relinquish_cookie(fsc->fscache, 0);
	353	fsc->fscache = NULL;
	354	}
	355
f7f7e7a0 YZ	356	/*
	357	* caller should hold CEPH_CAP_FILE_{RD,CACHE}
	358	*/
	359	void ceph_fscache_revalidate_cookie(struct ceph_inode_info *ci)
99ccbd22	360	{
f7f7e7a0	361	if (cache_valid(ci))
e81568eb MT	362	return;
e81568eb MT	363
f7f7e7a0 YZ	364	/* resue i_truncate_mutex. There should be no pending
	365	* truncate while the caller holds CEPH_CAP_FILE_RD */
	366	mutex_lock(&ci->i_truncate_mutex);
	367	if (!cache_valid(ci)) {
	368	if (fscache_check_consistency(ci->fscache))
	369	fscache_invalidate(ci->fscache);
	370	spin_lock(&ci->i_ceph_lock);
	371	ci->i_fscache_gen = ci->i_rdcache_gen;
	372	spin_unlock(&ci->i_ceph_lock);
99ccbd22	373	}
f7f7e7a0	374	mutex_unlock(&ci->i_truncate_mutex);
99ccbd22	375	}