[mirror_ubuntu-eoan-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;
	u64	mtime_sec;
	u64	mtime_nsec;
};

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

static DEFINE_MUTEX(ceph_fscache_lock);
static LIST_HEAD(ceph_fscache_list);

struct ceph_fscache_entry {
	struct list_head list;
	struct fscache_cookie *fscache;
	size_t uniq_len;
	/* The following members must be last */
	struct ceph_fsid fsid;
	char uniquifier[0];
};

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

int __init 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)
{
	const struct ceph_fsid *fsid = &fsc->client->fsid;
	const char *fscache_uniq = fsc->mount_options->fscache_uniq;
	size_t uniq_len = fscache_uniq ? strlen(fscache_uniq) : 0;
	struct ceph_fscache_entry *ent;
	int err = 0;

	mutex_lock(&ceph_fscache_lock);
	list_for_each_entry(ent, &ceph_fscache_list, list) {
		if (memcmp(&ent->fsid, fsid, sizeof(*fsid)))
			continue;
		if (ent->uniq_len != uniq_len)
			continue;
		if (uniq_len && memcmp(ent->uniquifier, fscache_uniq, uniq_len))
			continue;

		pr_err("fscache cookie already registered for fsid %pU\n", fsid);
		pr_err("  use fsc=%%s mount option to specify a uniquifier\n");
		err = -EBUSY;
		goto out_unlock;
	}

	ent = kzalloc(sizeof(*ent) + uniq_len, GFP_KERNEL);
	if (!ent) {
		err = -ENOMEM;
		goto out_unlock;
	}

	memcpy(&ent->fsid, fsid, sizeof(*fsid));
	if (uniq_len > 0) {
		memcpy(&ent->uniquifier, fscache_uniq, uniq_len);
		ent->uniq_len = uniq_len;
	}

	fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index,
					      &ceph_fscache_fsid_object_def,
					      &ent->fsid, sizeof(ent->fsid) + uniq_len,
					      NULL, 0,
					      fsc, 0, true);

	if (fsc->fscache) {
		ent->fscache = fsc->fscache;
		list_add_tail(&ent->list, &ceph_fscache_list);
	} else {
		kfree(ent);
		pr_err("unable to register fscache cookie for fsid %pU\n",
		       fsid);
		/* all other fs ignore this error */
	}
out_unlock:
	mutex_unlock(&ceph_fscache_lock);
	return err;
}

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

	if (dlen != sizeof(aux) ||
	    i_size_read(inode) != object_size)
		return FSCACHE_CHECKAUX_OBSOLETE;

	memset(&aux, 0, sizeof(aux));
	aux.version = ci->i_version;
	aux.mtime_sec = inode->i_mtime.tv_sec;
	aux.mtime_nsec = inode->i_mtime.tv_nsec;

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

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

static const struct fscache_cookie_def ceph_fscache_inode_object_def = {
	.name		= "CEPH.inode",
	.type		= FSCACHE_COOKIE_TYPE_DATAFILE,
	.check_aux	= ceph_fscache_inode_check_aux,
};

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);
	struct ceph_aux_inode aux;

	/* No caching for filesystem */
	if (!fsc->fscache)
		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) {
		memset(&aux, 0, sizeof(aux));
		aux.version = ci->i_version;
		aux.mtime_sec = inode->i_mtime.tv_sec;
		aux.mtime_nsec = inode->i_mtime.tv_nsec;
		ci->fscache = fscache_acquire_cookie(fsc->fscache,
						     &ceph_fscache_inode_object_def,
						     &ci->i_vino, sizeof(ci->i_vino),
						     &aux, sizeof(aux),
						     ci, i_size_read(inode), 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, &ci->i_vino, false);
}

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, &ci->i_vino, false);
		fscache_uncache_all_inode_pages(ci->fscache, inode);
	} else {
		fscache_enable_cookie(ci->fscache, &ci->i_vino, i_size_read(inode),
				      ceph_fscache_can_enable, inode);
		if (fscache_cookie_enabled(ci->fscache)) {
			dout("fscache_file_set_cookie %p %p enabling cache\n",
			     inode, filp);
		}
	}
}

static void ceph_readpage_from_fscache_complete(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_readpage_from_fscache_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_readpage_from_fscache_complete,
					  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, i_size_read(inode),
				 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)
{
	if (fscache_cookie_valid(fsc->fscache)) {
		struct ceph_fscache_entry *ent;
		bool found = false;

		mutex_lock(&ceph_fscache_lock);
		list_for_each_entry(ent, &ceph_fscache_list, list) {
			if (ent->fscache == fsc->fscache) {
				list_del(&ent->list);
				kfree(ent);
				found = true;
				break;
			}
		}
		WARN_ON_ONCE(!found);
		mutex_unlock(&ceph_fscache_lock);

		__fscache_relinquish_cookie(fsc->fscache, NULL, false);
	}
	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, &ci->i_vino))
			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 {
9bbeab41 AB	28	u64 version;
	29	u64 mtime_sec;
	30	u64 mtime_nsec;
99ccbd22 MT	31	};
	32
	33	struct fscache_netfs ceph_cache_netfs = {
	34	.name = "ceph",
	35	.version = 0,
	36	};
	37
1d8f8360 YZ	38	static DEFINE_MUTEX(ceph_fscache_lock);
	39	static LIST_HEAD(ceph_fscache_list);
	40
	41	struct ceph_fscache_entry {
	42	struct list_head list;
	43	struct fscache_cookie *fscache;
1d8f8360	44	size_t uniq_len;
402cb8dd DH	45	/* The following members must be last */
402cb8dd DH	46	struct ceph_fsid fsid;
1d8f8360 YZ	47	char uniquifier[0];
	48	};
	49
99ccbd22 MT	50	static const struct fscache_cookie_def ceph_fscache_fsid_object_def = {
	51	.name = "CEPH.fsid",
	52	.type = FSCACHE_COOKIE_TYPE_INDEX,
99ccbd22 MT	53	};
99ccbd22 MT	54
57a35dfb	55	int __init ceph_fscache_register(void)
99ccbd22 MT	56	{
	57	return fscache_register_netfs(&ceph_cache_netfs);
	58	}
	59
971f0bde	60	void ceph_fscache_unregister(void)
99ccbd22 MT	61	{
	62	fscache_unregister_netfs(&ceph_cache_netfs);
	63	}
	64
	65	int ceph_fscache_register_fs(struct ceph_fs_client* fsc)
	66	{
1d8f8360 YZ	67	const struct ceph_fsid *fsid = &fsc->client->fsid;
	68	const char *fscache_uniq = fsc->mount_options->fscache_uniq;
	69	size_t uniq_len = fscache_uniq ? strlen(fscache_uniq) : 0;
	70	struct ceph_fscache_entry *ent;
	71	int err = 0;
	72
	73	mutex_lock(&ceph_fscache_lock);
	74	list_for_each_entry(ent, &ceph_fscache_list, list) {
	75	if (memcmp(&ent->fsid, fsid, sizeof(*fsid)))
	76	continue;
	77	if (ent->uniq_len != uniq_len)
	78	continue;
	79	if (uniq_len && memcmp(ent->uniquifier, fscache_uniq, uniq_len))
	80	continue;
	81
	82	pr_err("fscache cookie already registered for fsid %pU\n", fsid);
	83	pr_err(" use fsc=%%s mount option to specify a uniquifier\n");
	84	err = -EBUSY;
	85	goto out_unlock;
	86	}
	87
	88	ent = kzalloc(sizeof(*ent) + uniq_len, GFP_KERNEL);
	89	if (!ent) {
	90	err = -ENOMEM;
	91	goto out_unlock;
	92	}
	93
402cb8dd DH	94	memcpy(&ent->fsid, fsid, sizeof(*fsid));
	95	if (uniq_len > 0) {
	96	memcpy(&ent->uniquifier, fscache_uniq, uniq_len);
	97	ent->uniq_len = uniq_len;
	98	}
	99
99ccbd22 MT	100	fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index,
99ccbd22 MT	101	&ceph_fscache_fsid_object_def,
402cb8dd DH	102	&ent->fsid, sizeof(ent->fsid) + uniq_len,
402cb8dd DH	103	NULL, 0,
ee1235a9	104	fsc, 0, true);
99ccbd22	105
1d8f8360	106	if (fsc->fscache) {
1d8f8360 YZ	107	ent->fscache = fsc->fscache;
	108	list_add_tail(&ent->list, &ceph_fscache_list);
	109	} else {
	110	kfree(ent);
	111	pr_err("unable to register fscache cookie for fsid %pU\n",
	112	fsid);
	113	/* all other fs ignore this error */
	114	}
	115	out_unlock:
	116	mutex_unlock(&ceph_fscache_lock);
	117	return err;
99ccbd22 MT	118	}
99ccbd22 MT	119
99ccbd22	120	static enum fscache_checkaux ceph_fscache_inode_check_aux(
ee1235a9 DH	121	void cookie_netfs_data, const void data, uint16_t dlen,
ee1235a9 DH	122	loff_t object_size)
99ccbd22 MT	123	{
	124	struct ceph_aux_inode aux;
	125	struct ceph_inode_info* ci = cookie_netfs_data;
	126	struct inode* inode = &ci->vfs_inode;
	127
ee1235a9 DH	128	if (dlen != sizeof(aux) \|\|
ee1235a9 DH	129	i_size_read(inode) != object_size)
99ccbd22 MT	130	return FSCACHE_CHECKAUX_OBSOLETE;
	131
	132	memset(&aux, 0, sizeof(aux));
f6973c09	133	aux.version = ci->i_version;
9bbeab41 AB	134	aux.mtime_sec = inode->i_mtime.tv_sec;
9bbeab41 AB	135	aux.mtime_nsec = inode->i_mtime.tv_nsec;
99ccbd22 MT	136
	137	if (memcmp(data, &aux, sizeof(aux)) != 0)
	138	return FSCACHE_CHECKAUX_OBSOLETE;
	139
4c069a58	140	dout("ceph inode 0x%p cached okay\n", ci);
99ccbd22 MT	141	return FSCACHE_CHECKAUX_OKAY;
	142	}
	143
99ccbd22 MT	144	static const struct fscache_cookie_def ceph_fscache_inode_object_def = {
	145	.name = "CEPH.inode",
	146	.type = FSCACHE_COOKIE_TYPE_DATAFILE,
99ccbd22	147	.check_aux = ceph_fscache_inode_check_aux,
99ccbd22 MT	148	};
99ccbd22 MT	149
46b59b2b	150	void ceph_fscache_register_inode_cookie(struct inode *inode)
99ccbd22	151	{
46b59b2b YZ	152	struct ceph_inode_info *ci = ceph_inode(inode);
46b59b2b YZ	153	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
402cb8dd	154	struct ceph_aux_inode aux;
99ccbd22 MT	155
99ccbd22 MT	156	/* No caching for filesystem */
d37b1d99	157	if (!fsc->fscache)
99ccbd22 MT	158	return;
	159
	160	/* Only cache for regular files that are read only */
46b59b2b	161	if (!S_ISREG(inode->i_mode))
99ccbd22 MT	162	return;
99ccbd22 MT	163
46b59b2b YZ	164	inode_lock_nested(inode, I_MUTEX_CHILD);
46b59b2b YZ	165	if (!ci->fscache) {
402cb8dd DH	166	memset(&aux, 0, sizeof(aux));
402cb8dd DH	167	aux.version = ci->i_version;
9bbeab41 AB	168	aux.mtime_sec = inode->i_mtime.tv_sec;
9bbeab41 AB	169	aux.mtime_nsec = inode->i_mtime.tv_nsec;
46b59b2b	170	ci->fscache = fscache_acquire_cookie(fsc->fscache,
402cb8dd DH	171	&ceph_fscache_inode_object_def,
	172	&ci->i_vino, sizeof(ci->i_vino),
	173	&aux, sizeof(aux),
ee1235a9	174	ci, i_size_read(inode), false);
46b59b2b	175	}
5955102c	176	inode_unlock(inode);
99ccbd22 MT	177	}
	178
	179	void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
	180	{
	181	struct fscache_cookie* cookie;
	182
	183	if ((cookie = ci->fscache) == NULL)
	184	return;
	185
	186	ci->fscache = NULL;
	187
	188	fscache_uncache_all_inode_pages(cookie, &ci->vfs_inode);
402cb8dd	189	fscache_relinquish_cookie(cookie, &ci->i_vino, false);
99ccbd22 MT	190	}
99ccbd22 MT	191
46b59b2b YZ	192	static bool ceph_fscache_can_enable(void *data)
	193	{
	194	struct inode *inode = data;
	195	return !inode_is_open_for_write(inode);
	196	}
	197
	198	void ceph_fscache_file_set_cookie(struct inode inode, struct file filp)
	199	{
	200	struct ceph_inode_info *ci = ceph_inode(inode);
	201
	202	if (!fscache_cookie_valid(ci->fscache))
	203	return;
	204
	205	if (inode_is_open_for_write(inode)) {
	206	dout("fscache_file_set_cookie %p %p disabling cache\n",
	207	inode, filp);
402cb8dd	208	fscache_disable_cookie(ci->fscache, &ci->i_vino, false);
46b59b2b YZ	209	fscache_uncache_all_inode_pages(ci->fscache, inode);
46b59b2b YZ	210	} else {
ee1235a9	211	fscache_enable_cookie(ci->fscache, &ci->i_vino, i_size_read(inode),
402cb8dd	212	ceph_fscache_can_enable, inode);
46b59b2b	213	if (fscache_cookie_enabled(ci->fscache)) {
0fbc5360	214	dout("fscache_file_set_cookie %p %p enabling cache\n",
46b59b2b YZ	215	inode, filp);
	216	}
	217	}
	218	}
	219
dd2bc473	220	static void ceph_readpage_from_fscache_complete(struct page page, void data, int error)
99ccbd22 MT	221	{
	222	if (!error)
	223	SetPageUptodate(page);
	224
	225	unlock_page(page);
	226	}
	227
3b33f692	228	static inline bool cache_valid(struct ceph_inode_info *ci)
99ccbd22	229	{
f7f7e7a0	230	return ci->i_fscache_gen == ci->i_rdcache_gen;
99ccbd22 MT	231	}
	232
	233
	234	/* Atempt to read from the fscache,
	235	*
	236	* This function is called from the readpage_nounlock context. DO NOT attempt to
	237	* unlock the page here (or in the callback).
	238	*/
	239	int ceph_readpage_from_fscache(struct inode inode, struct page page)
	240	{
	241	struct ceph_inode_info *ci = ceph_inode(inode);
	242	int ret;
	243
	244	if (!cache_valid(ci))
	245	return -ENOBUFS;
	246
	247	ret = fscache_read_or_alloc_page(ci->fscache, page,
dd2bc473	248	ceph_readpage_from_fscache_complete, NULL,
99ccbd22 MT	249	GFP_KERNEL);
	250
	251	switch (ret) {
	252	case 0: /* Page found */
	253	dout("page read submitted\n");
	254	return 0;
	255	case -ENOBUFS: /* Pages were not found, and can't be */
	256	case -ENODATA: /* Pages were not found */
	257	dout("page/inode not in cache\n");
	258	return ret;
	259	default:
	260	dout("%s: unknown error ret = %i\n", __func__, ret);
	261	return ret;
	262	}
	263	}
	264
	265	int ceph_readpages_from_fscache(struct inode *inode,
	266	struct address_space *mapping,
	267	struct list_head *pages,
	268	unsigned *nr_pages)
	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_pages(ci->fscache, mapping, pages, nr_pages,
dd2bc473	277	ceph_readpage_from_fscache_complete,
99ccbd22 MT	278	NULL, mapping_gfp_mask(mapping));
	279
	280	switch (ret) {
	281	case 0: /* All pages found */
	282	dout("all-page read submitted\n");
	283	return 0;
	284	case -ENOBUFS: /* Some pages were not found, and can't be */
	285	case -ENODATA: /* some 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	void ceph_readpage_to_fscache(struct inode inode, struct page page)
	295	{
	296	struct ceph_inode_info *ci = ceph_inode(inode);
	297	int ret;
	298
9b8dd1e8 MT	299	if (!PageFsCache(page))
	300	return;
	301
99ccbd22 MT	302	if (!cache_valid(ci))
	303	return;
	304
ee1235a9 DH	305	ret = fscache_write_page(ci->fscache, page, i_size_read(inode),
ee1235a9 DH	306	GFP_KERNEL);
99ccbd22 MT	307	if (ret)
	308	fscache_uncache_page(ci->fscache, page);
	309	}
	310
	311	void ceph_invalidate_fscache_page(struct inode* inode, struct page *page)
	312	{
	313	struct ceph_inode_info *ci = ceph_inode(inode);
	314
ffc79664 MT	315	if (!PageFsCache(page))
	316	return;
	317
99ccbd22 MT	318	fscache_wait_on_page_write(ci->fscache, page);
	319	fscache_uncache_page(ci->fscache, page);
	320	}
	321
	322	void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
	323	{
1d8f8360 YZ	324	if (fscache_cookie_valid(fsc->fscache)) {
	325	struct ceph_fscache_entry *ent;
	326	bool found = false;
	327
	328	mutex_lock(&ceph_fscache_lock);
	329	list_for_each_entry(ent, &ceph_fscache_list, list) {
	330	if (ent->fscache == fsc->fscache) {
	331	list_del(&ent->list);
	332	kfree(ent);
	333	found = true;
	334	break;
	335	}
	336	}
	337	WARN_ON_ONCE(!found);
	338	mutex_unlock(&ceph_fscache_lock);
	339
402cb8dd	340	__fscache_relinquish_cookie(fsc->fscache, NULL, false);
1d8f8360	341	}
99ccbd22 MT	342	fsc->fscache = NULL;
	343	}
	344
f7f7e7a0 YZ	345	/*
	346	* caller should hold CEPH_CAP_FILE_{RD,CACHE}
	347	*/
	348	void ceph_fscache_revalidate_cookie(struct ceph_inode_info *ci)
99ccbd22	349	{
f7f7e7a0	350	if (cache_valid(ci))
e81568eb MT	351	return;
e81568eb MT	352
f7f7e7a0 YZ	353	/* resue i_truncate_mutex. There should be no pending
	354	* truncate while the caller holds CEPH_CAP_FILE_RD */
	355	mutex_lock(&ci->i_truncate_mutex);
	356	if (!cache_valid(ci)) {
402cb8dd	357	if (fscache_check_consistency(ci->fscache, &ci->i_vino))
f7f7e7a0 YZ	358	fscache_invalidate(ci->fscache);
	359	spin_lock(&ci->i_ceph_lock);
	360	ci->i_fscache_gen = ci->i_rdcache_gen;
	361	spin_unlock(&ci->i_ceph_lock);
99ccbd22	362	}
f7f7e7a0	363	mutex_unlock(&ci->i_truncate_mutex);
99ccbd22	364	}