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Message-ID: <165643970911.84360.9864375814185644115.stgit@manet.1015granger.net>
Date: Tue, 28 Jun 2022 14:08:29 -0400
From: Chuck Lever <chuck.lever@...cle.com>
To: linux-nfs@...r.kernel.org, netdev@...r.kernel.org
Cc: david@...morbit.com, jlayton@...hat.com, tgraf@...g.ch
Subject: [PATCH v2 25/31] NFSD: Set up an rhashtable for the filecache
Add code to initialize and tear down an rhashtable. The rhashtable
is not used yet.
Signed-off-by: Chuck Lever <chuck.lever@...cle.com>
---
fs/nfsd/filecache.c | 160 ++++++++++++++++++++++++++++++++++++++++++++-------
fs/nfsd/filecache.h | 1
2 files changed, 140 insertions(+), 21 deletions(-)
diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index e47c7f387ef2..c15ccb2bd34b 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -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"
@@ -64,6 +65,136 @@ 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;
+
+struct nfsd_file_lookup_key {
+ struct inode *inode;
+ struct net *net;
+ const struct cred *cred;
+ unsigned char type;
+ unsigned char need;
+};
+
+enum {
+ NFSD_FILE_KEY_INODE,
+ NFSD_FILE_KEY_FULL,
+};
+
+/*
+ * The 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)
{
@@ -700,13 +831,18 @@ 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;
@@ -784,6 +920,7 @@ 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;
}
@@ -909,6 +1046,7 @@ 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;
@@ -920,26 +1058,6 @@ 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)
diff --git a/fs/nfsd/filecache.h b/fs/nfsd/filecache.h
index 31dc65f82c75..7fc017e7b09e 100644
--- a/fs/nfsd/filecache.h
+++ b/fs/nfsd/filecache.h
@@ -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;
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