From 2fb4af5ea3c735a205d97de10f044f809b20af51 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 18 Jul 2025 10:14:49 +0200 Subject: [PATCH] NFS: track active delegations per-server The active delegation watermark was added to avoid overloading servers. Track the active delegation per-server instead of globally so that clients talking to multiple servers aren't limited by the global limit. Signed-off-by: Christoph Hellwig Reviewed-by: Jeff Layton Link: https://lore.kernel.org/r/20250718081509.2607553-5-hch@lst.de Signed-off-by: Trond Myklebust --- fs/nfs/client.c | 1 + fs/nfs/delegation.c | 35 +++++++++++++++++++---------------- include/linux/nfs_fs_sb.h | 1 + 3 files changed, 21 insertions(+), 16 deletions(-) diff --git a/fs/nfs/client.c b/fs/nfs/client.c index 47258dc3af70..e13eb429b8b5 100644 --- a/fs/nfs/client.c +++ b/fs/nfs/client.c @@ -1005,6 +1005,7 @@ struct nfs_server *nfs_alloc_server(void) INIT_LIST_HEAD(&server->ss_src_copies); atomic_set(&server->active, 0); + atomic_long_set(&server->nr_active_delegations, 0); server->io_stats = nfs_alloc_iostats(); if (!server->io_stats) { diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c index 5f85966d7709..ea96f77e38c2 100644 --- a/fs/nfs/delegation.c +++ b/fs/nfs/delegation.c @@ -27,7 +27,6 @@ #define NFS_DEFAULT_DELEGATION_WATERMARK (5000U) -static atomic_long_t nfs_active_delegations; static unsigned nfs_delegation_watermark = NFS_DEFAULT_DELEGATION_WATERMARK; module_param_named(delegation_watermark, nfs_delegation_watermark, uint, 0644); @@ -38,11 +37,12 @@ static void __nfs_free_delegation(struct nfs_delegation *delegation) kfree_rcu(delegation, rcu); } -static void nfs_mark_delegation_revoked(struct nfs_delegation *delegation) +static void nfs_mark_delegation_revoked(struct nfs_server *server, + struct nfs_delegation *delegation) { if (!test_and_set_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) { delegation->stateid.type = NFS4_INVALID_STATEID_TYPE; - atomic_long_dec(&nfs_active_delegations); + atomic_long_dec(&server->nr_active_delegations); if (!test_bit(NFS_DELEGATION_RETURNING, &delegation->flags)) nfs_clear_verifier_delegated(delegation->inode); } @@ -60,9 +60,10 @@ static void nfs_put_delegation(struct nfs_delegation *delegation) __nfs_free_delegation(delegation); } -static void nfs_free_delegation(struct nfs_delegation *delegation) +static void nfs_free_delegation(struct nfs_server *server, + struct nfs_delegation *delegation) { - nfs_mark_delegation_revoked(delegation); + nfs_mark_delegation_revoked(server, delegation); nfs_put_delegation(delegation); } @@ -261,7 +262,7 @@ void nfs_inode_reclaim_delegation(struct inode *inode, const struct cred *cred, } clear_bit(NFS_DELEGATION_NEED_RECLAIM, &delegation->flags); if (test_and_clear_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) - atomic_long_inc(&nfs_active_delegations); + atomic_long_inc(&NFS_SERVER(inode)->nr_active_delegations); spin_unlock(&delegation->lock); rcu_read_unlock(); put_cred(oldcred); @@ -413,7 +414,8 @@ nfs_update_delegation_cred(struct nfs_delegation *delegation, } static void -nfs_update_inplace_delegation(struct nfs_delegation *delegation, +nfs_update_inplace_delegation(struct nfs_server *server, + struct nfs_delegation *delegation, const struct nfs_delegation *update) { if (nfs4_stateid_is_newer(&update->stateid, &delegation->stateid)) { @@ -426,7 +428,7 @@ nfs_update_inplace_delegation(struct nfs_delegation *delegation, nfs_update_delegation_cred(delegation, update->cred); /* smp_mb__before_atomic() is implicit due to xchg() */ clear_bit(NFS_DELEGATION_REVOKED, &delegation->flags); - atomic_long_inc(&nfs_active_delegations); + atomic_long_inc(&server->nr_active_delegations); } } } @@ -481,7 +483,7 @@ int nfs_inode_set_delegation(struct inode *inode, const struct cred *cred, if (nfs4_stateid_match_other(&old_delegation->stateid, &delegation->stateid)) { spin_lock(&old_delegation->lock); - nfs_update_inplace_delegation(old_delegation, + nfs_update_inplace_delegation(server, old_delegation, delegation); spin_unlock(&old_delegation->lock); goto out; @@ -530,7 +532,7 @@ add_new: rcu_assign_pointer(nfsi->delegation, delegation); delegation = NULL; - atomic_long_inc(&nfs_active_delegations); + atomic_long_inc(&server->nr_active_delegations); trace_nfs4_set_delegation(inode, type); @@ -544,7 +546,7 @@ out: __nfs_free_delegation(delegation); if (freeme != NULL) { nfs_do_return_delegation(inode, freeme, 0); - nfs_free_delegation(freeme); + nfs_free_delegation(server, freeme); } return status; } @@ -756,7 +758,7 @@ void nfs_inode_evict_delegation(struct inode *inode) set_bit(NFS_DELEGATION_RETURNING, &delegation->flags); set_bit(NFS_DELEGATION_INODE_FREEING, &delegation->flags); nfs_do_return_delegation(inode, delegation, 1); - nfs_free_delegation(delegation); + nfs_free_delegation(NFS_SERVER(inode), delegation); } } @@ -842,7 +844,8 @@ void nfs4_inode_return_delegation_on_close(struct inode *inode) if (!delegation) goto out; if (test_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) || - atomic_long_read(&nfs_active_delegations) >= nfs_delegation_watermark) { + atomic_long_read(&NFS_SERVER(inode)->nr_active_delegations) >= + nfs_delegation_watermark) { spin_lock(&delegation->lock); if (delegation->inode && list_empty(&NFS_I(inode)->open_files) && @@ -1018,7 +1021,7 @@ static void nfs_revoke_delegation(struct inode *inode, } spin_unlock(&delegation->lock); } - nfs_mark_delegation_revoked(delegation); + nfs_mark_delegation_revoked(NFS_SERVER(inode), delegation); ret = true; out: rcu_read_unlock(); @@ -1050,7 +1053,7 @@ void nfs_delegation_mark_returned(struct inode *inode, delegation->stateid.seqid = stateid->seqid; } - nfs_mark_delegation_revoked(delegation); + nfs_mark_delegation_revoked(NFS_SERVER(inode), delegation); clear_bit(NFS_DELEGATION_RETURNING, &delegation->flags); spin_unlock(&delegation->lock); if (nfs_detach_delegation(NFS_I(inode), delegation, NFS_SERVER(inode))) @@ -1270,7 +1273,7 @@ restart: if (delegation != NULL) { if (nfs_detach_delegation(NFS_I(inode), delegation, server) != NULL) - nfs_free_delegation(delegation); + nfs_free_delegation(server, delegation); /* Match nfs_start_delegation_return_locked */ nfs_put_delegation(delegation); } diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h index d2d36711a119..a9b44f12623f 100644 --- a/include/linux/nfs_fs_sb.h +++ b/include/linux/nfs_fs_sb.h @@ -254,6 +254,7 @@ struct nfs_server { struct list_head state_owners_lru; struct list_head layouts; struct list_head delegations; + atomic_long_t nr_active_delegations; struct list_head ss_copies; struct list_head ss_src_copies; -- 2.25.1