Commit fc22945e authored by Chuck Lever's avatar Chuck Lever
Browse files

NFSD: Set up an rhashtable for the filecache 



Add code to initialize and tear down an rhashtable. The rhashtable
is not used yet.

Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent c7b824c3

fs/nfsd/filecache.c

+139 −21
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/fsnotify_backend.h>

#include <linux/fsnotify.h>

#include <linux/seq_file.h>

#include <linux/rhashtable.h>



#include "vfs.h"

#include "nfsd.h"
@@ -63,6 +64,136 @@ static unsigned long nfsd_file_flags; 
static struct fsnotify_group		*nfsd_file_fsnotify_group;

static atomic_long_t			nfsd_filecache_count;

static struct delayed_work		nfsd_filecache_laundrette;

static struct rhashtable		nfsd_file_rhash_tbl

						____cacheline_aligned_in_smp;



enum nfsd_file_lookup_type {

	NFSD_FILE_KEY_INODE,

	NFSD_FILE_KEY_FULL,

};



struct nfsd_file_lookup_key {

	struct inode			*inode;

	struct net			*net;

	const struct cred		*cred;

	unsigned char			need;

	enum nfsd_file_lookup_type	type;

};



/*

 * The returned hash value is based solely on the address of an in-code

 * inode, a pointer to a slab-allocated object. The entropy in such a

 * pointer is concentrated in its middle bits.

 */

static u32 nfsd_file_inode_hash(const struct inode *inode, u32 seed)

{

	unsigned long ptr = (unsigned long)inode;

	u32 k;



	k = ptr >> L1_CACHE_SHIFT;

	k &= 0x00ffffff;

	return jhash2(&k, 1, seed);

}



/**

 * nfsd_file_key_hashfn - Compute the hash value of a lookup key

 * @data: key on which to compute the hash value

 * @len: rhash table's key_len parameter (unused)

 * @seed: rhash table's random seed of the day

 *

 * Return value:

 *   Computed 32-bit hash value

 */

static u32 nfsd_file_key_hashfn(const void *data, u32 len, u32 seed)

{

	const struct nfsd_file_lookup_key *key = data;



	return nfsd_file_inode_hash(key->inode, seed);

}



/**

 * nfsd_file_obj_hashfn - Compute the hash value of an nfsd_file

 * @data: object on which to compute the hash value

 * @len: rhash table's key_len parameter (unused)

 * @seed: rhash table's random seed of the day

 *

 * Return value:

 *   Computed 32-bit hash value

 */

static u32 nfsd_file_obj_hashfn(const void *data, u32 len, u32 seed)

{

	const struct nfsd_file *nf = data;



	return nfsd_file_inode_hash(nf->nf_inode, seed);

}



static bool

nfsd_match_cred(const struct cred *c1, const struct cred *c2)

{

	int i;



	if (!uid_eq(c1->fsuid, c2->fsuid))

		return false;

	if (!gid_eq(c1->fsgid, c2->fsgid))

		return false;

	if (c1->group_info == NULL || c2->group_info == NULL)

		return c1->group_info == c2->group_info;

	if (c1->group_info->ngroups != c2->group_info->ngroups)

		return false;

	for (i = 0; i < c1->group_info->ngroups; i++) {

		if (!gid_eq(c1->group_info->gid[i], c2->group_info->gid[i]))

			return false;

	}

	return true;

}



/**

 * nfsd_file_obj_cmpfn - Match a cache item against search criteria

 * @arg: search criteria

 * @ptr: cache item to check

 *

 * Return values:

 *   %0 - Item matches search criteria

 *   %1 - Item does not match search criteria

 */

static int nfsd_file_obj_cmpfn(struct rhashtable_compare_arg *arg,

			       const void *ptr)

{

	const struct nfsd_file_lookup_key *key = arg->key;

	const struct nfsd_file *nf = ptr;



	switch (key->type) {

	case NFSD_FILE_KEY_INODE:

		if (nf->nf_inode != key->inode)

			return 1;

		break;

	case NFSD_FILE_KEY_FULL:

		if (nf->nf_inode != key->inode)

			return 1;

		if (nf->nf_may != key->need)

			return 1;

		if (nf->nf_net != key->net)

			return 1;

		if (!nfsd_match_cred(nf->nf_cred, key->cred))

			return 1;

		if (test_bit(NFSD_FILE_HASHED, &nf->nf_flags) == 0)

			return 1;

		break;

	}

	return 0;

}



static const struct rhashtable_params nfsd_file_rhash_params = {

	.key_len		= sizeof_field(struct nfsd_file, nf_inode),

	.key_offset		= offsetof(struct nfsd_file, nf_inode),

	.head_offset		= offsetof(struct nfsd_file, nf_rhash),

	.hashfn			= nfsd_file_key_hashfn,

	.obj_hashfn		= nfsd_file_obj_hashfn,

	.obj_cmpfn		= nfsd_file_obj_cmpfn,

	/* Reduce resizing churn on light workloads */

	.min_size		= 512,		/* buckets */

	.automatic_shrinking	= true,

};



static void

nfsd_file_schedule_laundrette(void)
@@ -694,13 +825,18 @@ static const struct fsnotify_ops nfsd_file_fsnotify_ops = { 
int

nfsd_file_cache_init(void)

{

	int		ret = -ENOMEM;

	int		ret;

	unsigned int	i;



	lockdep_assert_held(&nfsd_mutex);

	if (test_and_set_bit(NFSD_FILE_CACHE_UP, &nfsd_file_flags) == 1)

		return 0;



	ret = rhashtable_init(&nfsd_file_rhash_tbl, &nfsd_file_rhash_params);

	if (ret)

		return ret;



	ret = -ENOMEM;

	nfsd_filecache_wq = alloc_workqueue("nfsd_filecache", 0, 0);

	if (!nfsd_filecache_wq)

		goto out;
@@ -778,6 +914,7 @@ nfsd_file_cache_init(void) 
	nfsd_file_hashtbl = NULL;

	destroy_workqueue(nfsd_filecache_wq);

	nfsd_filecache_wq = NULL;

	rhashtable_destroy(&nfsd_file_rhash_tbl);

	goto out;

}
@@ -903,6 +1040,7 @@ nfsd_file_cache_shutdown(void) 
	nfsd_file_hashtbl = NULL;

	destroy_workqueue(nfsd_filecache_wq);

	nfsd_filecache_wq = NULL;

	rhashtable_destroy(&nfsd_file_rhash_tbl);



	for_each_possible_cpu(i) {

		per_cpu(nfsd_file_cache_hits, i) = 0;
@@ -914,26 +1052,6 @@ nfsd_file_cache_shutdown(void) 
	}

}



static bool

nfsd_match_cred(const struct cred *c1, const struct cred *c2)

{

	int i;



	if (!uid_eq(c1->fsuid, c2->fsuid))

		return false;

	if (!gid_eq(c1->fsgid, c2->fsgid))

		return false;

	if (c1->group_info == NULL || c2->group_info == NULL)

		return c1->group_info == c2->group_info;

	if (c1->group_info->ngroups != c2->group_info->ngroups)

		return false;

	for (i = 0; i < c1->group_info->ngroups; i++) {

		if (!gid_eq(c1->group_info->gid[i], c2->group_info->gid[i]))

			return false;

	}

	return true;

}



static struct nfsd_file *

nfsd_file_find_locked(struct inode *inode, unsigned int may_flags,

			unsigned int hashval, struct net *net)

fs/nfsd/filecache.h

+1 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ struct nfsd_file_mark { 
 * never be dereferenced, only used for comparison.

 */

struct nfsd_file {

	struct rhash_head	nf_rhash;

	struct hlist_node	nf_node;

	struct list_head	nf_lru;

	struct rcu_head		nf_rcu;