From b757144fd77cf5512f5b60179ba5ca8dcc5184b4 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Wed, 3 Apr 2013 14:33:49 -0400 Subject: [PATCH] NFSv4: Be less aggressive about returning delegations for open files Currently, if the application that holds the file open isn't doing I/O, we may end up returning the delegation. This means that we can no longer cache the file as aggressively, and often also that we multiply the state that both the server and the client needs to track. This patch adds a check for open files to the routine that scans for delegations that are unreferenced. Signed-off-by: Trond Myklebust --- fs/nfs/delegation.c | 30 +++++++++++++++++++++++++++--- fs/nfs/delegation.h | 1 + 2 files changed, 28 insertions(+), 3 deletions(-) diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c index fc8a213497a1..a377ea36381e 100644 --- a/fs/nfs/delegation.c +++ b/fs/nfs/delegation.c @@ -389,6 +389,24 @@ out: return err; } +static bool nfs_delegation_need_return(struct nfs_delegation *delegation) +{ + bool ret = false; + + if (test_and_clear_bit(NFS_DELEGATION_RETURN, &delegation->flags)) + ret = true; + if (test_and_clear_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags) && !ret) { + struct inode *inode; + + spin_lock(&delegation->lock); + inode = delegation->inode; + if (inode && list_empty(&NFS_I(inode)->open_files)) + ret = true; + spin_unlock(&delegation->lock); + } + return ret; +} + /** * nfs_client_return_marked_delegations - return previously marked delegations * @clp: nfs_client to process @@ -411,8 +429,7 @@ restart: list_for_each_entry_rcu(server, &clp->cl_superblocks, client_link) { list_for_each_entry_rcu(delegation, &server->delegations, super_list) { - if (!test_and_clear_bit(NFS_DELEGATION_RETURN, - &delegation->flags)) + if (!nfs_delegation_need_return(delegation)) continue; inode = nfs_delegation_grab_inode(delegation); if (inode == NULL) @@ -471,6 +488,13 @@ int nfs4_inode_return_delegation(struct inode *inode) return err; } +static void nfs_mark_return_if_closed_delegation(struct nfs_server *server, + struct nfs_delegation *delegation) +{ + set_bit(NFS_DELEGATION_RETURN_IF_CLOSED, &delegation->flags); + set_bit(NFS4CLNT_DELEGRETURN, &server->nfs_client->cl_state); +} + static void nfs_mark_return_delegation(struct nfs_server *server, struct nfs_delegation *delegation) { @@ -574,7 +598,7 @@ static void nfs_mark_return_unreferenced_delegations(struct nfs_server *server) list_for_each_entry_rcu(delegation, &server->delegations, super_list) { if (test_and_clear_bit(NFS_DELEGATION_REFERENCED, &delegation->flags)) continue; - nfs_mark_return_delegation(server, delegation); + nfs_mark_return_if_closed_delegation(server, delegation); } } diff --git a/fs/nfs/delegation.h b/fs/nfs/delegation.h index 88573d107502..22f0a138e551 100644 --- a/fs/nfs/delegation.h +++ b/fs/nfs/delegation.h @@ -28,6 +28,7 @@ struct nfs_delegation { enum { NFS_DELEGATION_NEED_RECLAIM = 0, NFS_DELEGATION_RETURN, + NFS_DELEGATION_RETURN_IF_CLOSED, NFS_DELEGATION_REFERENCED, NFS_DELEGATION_RETURNING, }; -- 2.20.1