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

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Ceph cache definitions.
 *
 *  Copyright (C) 2013 by Adfin Solutions, Inc. All Rights Reserved.
 *  Written by Milosz Tanski (milosz@adfin.com)
 */

#include <linux/ceph/ceph_debug.h>

#include <linux/fs_context.h>
#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[];
};

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, struct fs_context *fc)
{
	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;

		errorfc(fc, "fscache cookie already registered for fsid %pU, use fsc=<uniquifier> option",
		       fsid);
		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);
		errorfc(fc, "unable to register fscache cookie for fsid %pU",
		       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
1f327613	1	// SPDX-License-Identifier: GPL-2.0-only
99ccbd22 MT	2	/*
	3	* Ceph cache definitions.
	4	*
	5	* Copyright (C) 2013 by Adfin Solutions, Inc. All Rights Reserved.
	6	* Written by Milosz Tanski (milosz@adfin.com)
99ccbd22 MT	7	*/
99ccbd22 MT	8
48f930ea ID	9	#include <linux/ceph/ceph_debug.h>
48f930ea ID	10
82995cc6	11	#include <linux/fs_context.h>
99ccbd22 MT	12	#include "super.h"
	13	#include "cache.h"
	14
	15	struct ceph_aux_inode {
9bbeab41 AB	16	u64 version;
	17	u64 mtime_sec;
	18	u64 mtime_nsec;
99ccbd22 MT	19	};
	20
	21	struct fscache_netfs ceph_cache_netfs = {
	22	.name = "ceph",
	23	.version = 0,
	24	};
	25
1d8f8360 YZ	26	static DEFINE_MUTEX(ceph_fscache_lock);
	27	static LIST_HEAD(ceph_fscache_list);
	28
	29	struct ceph_fscache_entry {
	30	struct list_head list;
	31	struct fscache_cookie *fscache;
1d8f8360	32	size_t uniq_len;
402cb8dd DH	33	/* The following members must be last */
402cb8dd DH	34	struct ceph_fsid fsid;
f682dc71	35	char uniquifier[];
1d8f8360 YZ	36	};
1d8f8360 YZ	37
99ccbd22 MT	38	static const struct fscache_cookie_def ceph_fscache_fsid_object_def = {
	39	.name = "CEPH.fsid",
	40	.type = FSCACHE_COOKIE_TYPE_INDEX,
99ccbd22 MT	41	};
99ccbd22 MT	42
57a35dfb	43	int __init ceph_fscache_register(void)
99ccbd22 MT	44	{
	45	return fscache_register_netfs(&ceph_cache_netfs);
	46	}
	47
971f0bde	48	void ceph_fscache_unregister(void)
99ccbd22 MT	49	{
	50	fscache_unregister_netfs(&ceph_cache_netfs);
	51	}
	52
82995cc6	53	int ceph_fscache_register_fs(struct ceph_fs_client* fsc, struct fs_context *fc)
99ccbd22	54	{
1d8f8360 YZ	55	const struct ceph_fsid *fsid = &fsc->client->fsid;
	56	const char *fscache_uniq = fsc->mount_options->fscache_uniq;
	57	size_t uniq_len = fscache_uniq ? strlen(fscache_uniq) : 0;
	58	struct ceph_fscache_entry *ent;
	59	int err = 0;
	60
	61	mutex_lock(&ceph_fscache_lock);
	62	list_for_each_entry(ent, &ceph_fscache_list, list) {
	63	if (memcmp(&ent->fsid, fsid, sizeof(*fsid)))
	64	continue;
	65	if (ent->uniq_len != uniq_len)
	66	continue;
	67	if (uniq_len && memcmp(ent->uniquifier, fscache_uniq, uniq_len))
	68	continue;
	69
d53d0f74	70	errorfc(fc, "fscache cookie already registered for fsid %pU, use fsc=<uniquifier> option",
82995cc6	71	fsid);
1d8f8360 YZ	72	err = -EBUSY;
	73	goto out_unlock;
	74	}
	75
	76	ent = kzalloc(sizeof(*ent) + uniq_len, GFP_KERNEL);
	77	if (!ent) {
	78	err = -ENOMEM;
	79	goto out_unlock;
	80	}
	81
402cb8dd DH	82	memcpy(&ent->fsid, fsid, sizeof(*fsid));
	83	if (uniq_len > 0) {
	84	memcpy(&ent->uniquifier, fscache_uniq, uniq_len);
	85	ent->uniq_len = uniq_len;
	86	}
	87
99ccbd22 MT	88	fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index,
99ccbd22 MT	89	&ceph_fscache_fsid_object_def,
402cb8dd DH	90	&ent->fsid, sizeof(ent->fsid) + uniq_len,
402cb8dd DH	91	NULL, 0,
ee1235a9	92	fsc, 0, true);
99ccbd22	93
1d8f8360	94	if (fsc->fscache) {
1d8f8360 YZ	95	ent->fscache = fsc->fscache;
	96	list_add_tail(&ent->list, &ceph_fscache_list);
	97	} else {
	98	kfree(ent);
d53d0f74	99	errorfc(fc, "unable to register fscache cookie for fsid %pU",
1d8f8360 YZ	100	fsid);
	101	/* all other fs ignore this error */
	102	}
	103	out_unlock:
	104	mutex_unlock(&ceph_fscache_lock);
	105	return err;
99ccbd22 MT	106	}
99ccbd22 MT	107
99ccbd22	108	static enum fscache_checkaux ceph_fscache_inode_check_aux(
ee1235a9 DH	109	void cookie_netfs_data, const void data, uint16_t dlen,
ee1235a9 DH	110	loff_t object_size)
99ccbd22 MT	111	{
	112	struct ceph_aux_inode aux;
	113	struct ceph_inode_info* ci = cookie_netfs_data;
	114	struct inode* inode = &ci->vfs_inode;
	115
ee1235a9 DH	116	if (dlen != sizeof(aux) \|\|
ee1235a9 DH	117	i_size_read(inode) != object_size)
99ccbd22 MT	118	return FSCACHE_CHECKAUX_OBSOLETE;
	119
	120	memset(&aux, 0, sizeof(aux));
f6973c09	121	aux.version = ci->i_version;
9bbeab41 AB	122	aux.mtime_sec = inode->i_mtime.tv_sec;
9bbeab41 AB	123	aux.mtime_nsec = inode->i_mtime.tv_nsec;
99ccbd22 MT	124
	125	if (memcmp(data, &aux, sizeof(aux)) != 0)
	126	return FSCACHE_CHECKAUX_OBSOLETE;
	127
4c069a58	128	dout("ceph inode 0x%p cached okay\n", ci);
99ccbd22 MT	129	return FSCACHE_CHECKAUX_OKAY;
	130	}
	131
99ccbd22 MT	132	static const struct fscache_cookie_def ceph_fscache_inode_object_def = {
	133	.name = "CEPH.inode",
	134	.type = FSCACHE_COOKIE_TYPE_DATAFILE,
99ccbd22	135	.check_aux = ceph_fscache_inode_check_aux,
99ccbd22 MT	136	};
99ccbd22 MT	137
46b59b2b	138	void ceph_fscache_register_inode_cookie(struct inode *inode)
99ccbd22	139	{
46b59b2b YZ	140	struct ceph_inode_info *ci = ceph_inode(inode);
46b59b2b YZ	141	struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
402cb8dd	142	struct ceph_aux_inode aux;
99ccbd22 MT	143
99ccbd22 MT	144	/* No caching for filesystem */
d37b1d99	145	if (!fsc->fscache)
99ccbd22 MT	146	return;
	147
	148	/* Only cache for regular files that are read only */
46b59b2b	149	if (!S_ISREG(inode->i_mode))
99ccbd22 MT	150	return;
99ccbd22 MT	151
46b59b2b YZ	152	inode_lock_nested(inode, I_MUTEX_CHILD);
46b59b2b YZ	153	if (!ci->fscache) {
402cb8dd DH	154	memset(&aux, 0, sizeof(aux));
402cb8dd DH	155	aux.version = ci->i_version;
9bbeab41 AB	156	aux.mtime_sec = inode->i_mtime.tv_sec;
9bbeab41 AB	157	aux.mtime_nsec = inode->i_mtime.tv_nsec;
46b59b2b	158	ci->fscache = fscache_acquire_cookie(fsc->fscache,
402cb8dd DH	159	&ceph_fscache_inode_object_def,
	160	&ci->i_vino, sizeof(ci->i_vino),
	161	&aux, sizeof(aux),
ee1235a9	162	ci, i_size_read(inode), false);
46b59b2b	163	}
5955102c	164	inode_unlock(inode);
99ccbd22 MT	165	}
	166
	167	void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci)
	168	{
	169	struct fscache_cookie* cookie;
	170
	171	if ((cookie = ci->fscache) == NULL)
	172	return;
	173
	174	ci->fscache = NULL;
	175
	176	fscache_uncache_all_inode_pages(cookie, &ci->vfs_inode);
402cb8dd	177	fscache_relinquish_cookie(cookie, &ci->i_vino, false);
99ccbd22 MT	178	}
99ccbd22 MT	179
46b59b2b YZ	180	static bool ceph_fscache_can_enable(void *data)
	181	{
	182	struct inode *inode = data;
	183	return !inode_is_open_for_write(inode);
	184	}
	185
	186	void ceph_fscache_file_set_cookie(struct inode inode, struct file filp)
	187	{
	188	struct ceph_inode_info *ci = ceph_inode(inode);
	189
	190	if (!fscache_cookie_valid(ci->fscache))
	191	return;
	192
	193	if (inode_is_open_for_write(inode)) {
	194	dout("fscache_file_set_cookie %p %p disabling cache\n",
	195	inode, filp);
402cb8dd	196	fscache_disable_cookie(ci->fscache, &ci->i_vino, false);
46b59b2b YZ	197	fscache_uncache_all_inode_pages(ci->fscache, inode);
46b59b2b YZ	198	} else {
ee1235a9	199	fscache_enable_cookie(ci->fscache, &ci->i_vino, i_size_read(inode),
402cb8dd	200	ceph_fscache_can_enable, inode);
46b59b2b	201	if (fscache_cookie_enabled(ci->fscache)) {
0fbc5360	202	dout("fscache_file_set_cookie %p %p enabling cache\n",
46b59b2b YZ	203	inode, filp);
	204	}
	205	}
	206	}
	207
dd2bc473	208	static void ceph_readpage_from_fscache_complete(struct page page, void data, int error)
99ccbd22 MT	209	{
	210	if (!error)
	211	SetPageUptodate(page);
	212
	213	unlock_page(page);
	214	}
	215
3b33f692	216	static inline bool cache_valid(struct ceph_inode_info *ci)
99ccbd22	217	{
f7f7e7a0	218	return ci->i_fscache_gen == ci->i_rdcache_gen;
99ccbd22 MT	219	}
	220
	221
	222	/* Atempt to read from the fscache,
	223	*
	224	* This function is called from the readpage_nounlock context. DO NOT attempt to
	225	* unlock the page here (or in the callback).
	226	*/
	227	int ceph_readpage_from_fscache(struct inode inode, struct page page)
	228	{
	229	struct ceph_inode_info *ci = ceph_inode(inode);
	230	int ret;
	231
	232	if (!cache_valid(ci))
	233	return -ENOBUFS;
	234
	235	ret = fscache_read_or_alloc_page(ci->fscache, page,
dd2bc473	236	ceph_readpage_from_fscache_complete, NULL,
99ccbd22 MT	237	GFP_KERNEL);
	238
	239	switch (ret) {
	240	case 0: /* Page found */
	241	dout("page read submitted\n");
	242	return 0;
	243	case -ENOBUFS: /* Pages were not found, and can't be */
	244	case -ENODATA: /* Pages were not found */
	245	dout("page/inode not in cache\n");
	246	return ret;
	247	default:
	248	dout("%s: unknown error ret = %i\n", __func__, ret);
	249	return ret;
	250	}
	251	}
	252
	253	int ceph_readpages_from_fscache(struct inode *inode,
	254	struct address_space *mapping,
	255	struct list_head *pages,
	256	unsigned *nr_pages)
	257	{
	258	struct ceph_inode_info *ci = ceph_inode(inode);
	259	int ret;
	260
	261	if (!cache_valid(ci))
	262	return -ENOBUFS;
	263
	264	ret = fscache_read_or_alloc_pages(ci->fscache, mapping, pages, nr_pages,
dd2bc473	265	ceph_readpage_from_fscache_complete,
99ccbd22 MT	266	NULL, mapping_gfp_mask(mapping));
	267
	268	switch (ret) {
	269	case 0: /* All pages found */
	270	dout("all-page read submitted\n");
	271	return 0;
	272	case -ENOBUFS: /* Some pages were not found, and can't be */
	273	case -ENODATA: /* some pages were not found */
	274	dout("page/inode not in cache\n");
	275	return ret;
	276	default:
	277	dout("%s: unknown error ret = %i\n", __func__, ret);
	278	return ret;
	279	}
	280	}
	281
	282	void ceph_readpage_to_fscache(struct inode inode, struct page page)
	283	{
	284	struct ceph_inode_info *ci = ceph_inode(inode);
	285	int ret;
	286
9b8dd1e8 MT	287	if (!PageFsCache(page))
	288	return;
	289
99ccbd22 MT	290	if (!cache_valid(ci))
	291	return;
	292
ee1235a9 DH	293	ret = fscache_write_page(ci->fscache, page, i_size_read(inode),
ee1235a9 DH	294	GFP_KERNEL);
99ccbd22 MT	295	if (ret)
	296	fscache_uncache_page(ci->fscache, page);
	297	}
	298
	299	void ceph_invalidate_fscache_page(struct inode* inode, struct page *page)
	300	{
	301	struct ceph_inode_info *ci = ceph_inode(inode);
	302
ffc79664 MT	303	if (!PageFsCache(page))
	304	return;
	305
99ccbd22 MT	306	fscache_wait_on_page_write(ci->fscache, page);
	307	fscache_uncache_page(ci->fscache, page);
	308	}
	309
	310	void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc)
	311	{
1d8f8360 YZ	312	if (fscache_cookie_valid(fsc->fscache)) {
	313	struct ceph_fscache_entry *ent;
	314	bool found = false;
	315
	316	mutex_lock(&ceph_fscache_lock);
	317	list_for_each_entry(ent, &ceph_fscache_list, list) {
	318	if (ent->fscache == fsc->fscache) {
	319	list_del(&ent->list);
	320	kfree(ent);
	321	found = true;
	322	break;
	323	}
	324	}
	325	WARN_ON_ONCE(!found);
	326	mutex_unlock(&ceph_fscache_lock);
	327
402cb8dd	328	__fscache_relinquish_cookie(fsc->fscache, NULL, false);
1d8f8360	329	}
99ccbd22 MT	330	fsc->fscache = NULL;
	331	}
	332
f7f7e7a0 YZ	333	/*
	334	* caller should hold CEPH_CAP_FILE_{RD,CACHE}
	335	*/
	336	void ceph_fscache_revalidate_cookie(struct ceph_inode_info *ci)
99ccbd22	337	{
f7f7e7a0	338	if (cache_valid(ci))
e81568eb MT	339	return;
e81568eb MT	340
f7f7e7a0 YZ	341	/* resue i_truncate_mutex. There should be no pending
	342	* truncate while the caller holds CEPH_CAP_FILE_RD */
	343	mutex_lock(&ci->i_truncate_mutex);
	344	if (!cache_valid(ci)) {
402cb8dd	345	if (fscache_check_consistency(ci->fscache, &ci->i_vino))
f7f7e7a0 YZ	346	fscache_invalidate(ci->fscache);
	347	spin_lock(&ci->i_ceph_lock);
	348	ci->i_fscache_gen = ci->i_rdcache_gen;
	349	spin_unlock(&ci->i_ceph_lock);
99ccbd22	350	}
f7f7e7a0	351	mutex_unlock(&ci->i_truncate_mutex);
99ccbd22	352	}