5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Chuck Lever chuck.lever@oracle.com
[ Upstream commit fc22945ecc2a0a028f3683115f98a922d506c284 ]
Add code to initialize and tear down an rhashtable. The rhashtable is not used yet.
Reviewed-by: Jeff Layton jlayton@kernel.org Signed-off-by: Chuck Lever chuck.lever@oracle.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 33bb4d31b4972..95e7e15b567e2 100644 --- a/fs/nfsd/filecache.c +++ b/fs/nfsd/filecache.c @@ -12,6 +12,7 @@ #include <linux/fsnotify_backend.h> #include <linux/fsnotify.h> #include <linux/seq_file.h> +#include <linux/rhashtable.h>
#include "vfs.h" #include "nfsd.h" @@ -62,6 +63,136 @@ 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) @@ -693,13 +824,18 @@ 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; @@ -777,6 +913,7 @@ 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; }
@@ -902,6 +1039,7 @@ 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; @@ -913,26 +1051,6 @@ 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 82051e1b8420d..5cbfc61a7d7d9 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;