From: Christoph Hellwig Date: Fri, 18 Jul 2025 08:14:50 +0000 (+0200) Subject: NFS: use a hash table for delegation lookup X-Git-Tag: v6.17-rc1~21^2~13 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f5b3108e6a14418b120a3c38ca589b8d6cf87627;p=thirdparty%2Fkernel%2Flinux.git NFS: use a hash table for delegation lookup nfs_delegation_find_inode currently has to walk the entire list of delegations per inode, which can become pretty large, and can become even larger when increasing the delegation watermark. Add a hash table to speed up the delegation lookup, sized as a fraction of the delegation watermark. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20250718081509.2607553-6-hch@lst.de Signed-off-by: Trond Myklebust --- diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c index ea96f77e38c2..9d3a5f29f17f 100644 --- a/fs/nfs/delegation.c +++ b/fs/nfs/delegation.c @@ -30,6 +30,13 @@ static unsigned nfs_delegation_watermark = NFS_DEFAULT_DELEGATION_WATERMARK; module_param_named(delegation_watermark, nfs_delegation_watermark, uint, 0644); +static struct hlist_head *nfs_delegation_hash(struct nfs_server *server, + const struct nfs_fh *fhandle) +{ + return server->delegation_hash_table + + (nfs_fhandle_hash(fhandle) & server->delegation_hash_mask); +} + static void __nfs_free_delegation(struct nfs_delegation *delegation) { put_cred(delegation->cred); @@ -367,6 +374,7 @@ nfs_detach_delegation_locked(struct nfs_inode *nfsi, spin_unlock(&delegation->lock); return NULL; } + hlist_del_init_rcu(&delegation->hash); list_del_rcu(&delegation->super_list); delegation->inode = NULL; rcu_assign_pointer(nfsi->delegation, NULL); @@ -529,6 +537,8 @@ add_new: spin_unlock(&inode->i_lock); list_add_tail_rcu(&delegation->super_list, &server->delegations); + hlist_add_head_rcu(&delegation->hash, + nfs_delegation_hash(server, &NFS_I(inode)->fh)); rcu_assign_pointer(nfsi->delegation, delegation); delegation = NULL; @@ -1166,11 +1176,12 @@ static struct inode * nfs_delegation_find_inode_server(struct nfs_server *server, const struct nfs_fh *fhandle) { + struct hlist_head *head = nfs_delegation_hash(server, fhandle); struct nfs_delegation *delegation; struct super_block *freeme = NULL; struct inode *res = NULL; - list_for_each_entry_rcu(delegation, &server->delegations, super_list) { + hlist_for_each_entry_rcu(delegation, head, hash) { spin_lock(&delegation->lock); if (delegation->inode != NULL && !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags) && @@ -1577,3 +1588,18 @@ out: rcu_read_unlock(); return ret; } + +int nfs4_delegation_hash_alloc(struct nfs_server *server) +{ + int delegation_buckets, i; + + delegation_buckets = roundup_pow_of_two(nfs_delegation_watermark / 16); + server->delegation_hash_mask = delegation_buckets - 1; + server->delegation_hash_table = kmalloc_array(delegation_buckets, + sizeof(*server->delegation_hash_table), GFP_KERNEL); + if (!server->delegation_hash_table) + return -ENOMEM; + for (i = 0; i < delegation_buckets; i++) + INIT_HLIST_HEAD(&server->delegation_hash_table[i]); + return 0; +} diff --git a/fs/nfs/delegation.h b/fs/nfs/delegation.h index 8ff5ab9c5c25..08ec2e9c68a4 100644 --- a/fs/nfs/delegation.h +++ b/fs/nfs/delegation.h @@ -14,6 +14,7 @@ * NFSv4 delegation */ struct nfs_delegation { + struct hlist_node hash; struct list_head super_list; const struct cred *cred; struct inode *inode; @@ -123,4 +124,6 @@ static inline int nfs_have_delegated_mtime(struct inode *inode) NFS_DELEGATION_FLAG_TIME); } +int nfs4_delegation_hash_alloc(struct nfs_server *server); + #endif diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c index 5943a192f36b..2ea98f1f116f 100644 --- a/fs/nfs/nfs4client.c +++ b/fs/nfs/nfs4client.c @@ -802,6 +802,7 @@ static void nfs4_destroy_server(struct nfs_server *server) unset_pnfs_layoutdriver(server); nfs4_purge_state_owners(server, &freeme); nfs4_free_state_owners(&freeme); + kfree(server->delegation_hash_table); } /* @@ -1096,6 +1097,10 @@ static int nfs4_server_common_setup(struct nfs_server *server, { int error; + error = nfs4_delegation_hash_alloc(server); + if (error) + return error; + /* data servers support only a subset of NFSv4.1 */ if (is_ds_only_client(server->nfs_client)) return -EPROTONOSUPPORT; diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c index ef2077e185b6..d8bebd757af3 100644 --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -10967,6 +10967,26 @@ static const struct inode_operations nfs4_file_inode_operations = { .listxattr = nfs4_listxattr, }; +static struct nfs_server *nfs4_clone_server(struct nfs_server *source, + struct nfs_fh *fh, struct nfs_fattr *fattr, + rpc_authflavor_t flavor) +{ + struct nfs_server *server; + int error; + + server = nfs_clone_server(source, fh, fattr, flavor); + if (IS_ERR(server)) + return server; + + error = nfs4_delegation_hash_alloc(server); + if (error) { + nfs_free_server(server); + return ERR_PTR(error); + } + + return server; +} + const struct nfs_rpc_ops nfs_v4_clientops = { .version = 4, /* protocol version */ .dentry_ops = &nfs4_dentry_operations, @@ -11019,7 +11039,7 @@ const struct nfs_rpc_ops nfs_v4_clientops = { .init_client = nfs4_init_client, .free_client = nfs4_free_client, .create_server = nfs4_create_server, - .clone_server = nfs_clone_server, + .clone_server = nfs4_clone_server, .discover_trunking = nfs4_discover_trunking, .enable_swap = nfs4_enable_swap, .disable_swap = nfs4_disable_swap, diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h index a9b44f12623f..d30c0245031c 100644 --- a/include/linux/nfs_fs_sb.h +++ b/include/linux/nfs_fs_sb.h @@ -255,6 +255,8 @@ struct nfs_server { struct list_head layouts; struct list_head delegations; atomic_long_t nr_active_delegations; + unsigned int delegation_hash_mask; + struct hlist_head *delegation_hash_table; struct list_head ss_copies; struct list_head ss_src_copies;