From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: linux-nfs-owner@vger.kernel.org Received: from mailhub.sw.ru ([195.214.232.25]:20882 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754200Ab2EVKZP (ORCPT ); Tue, 22 May 2012 06:25:15 -0400 Subject: [PATCH] NFSd: fix locking in nfsd_forget_delegations() To: bfields@fieldses.org From: Stanislav Kinsbursky Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, devel@openvz.org Date: Tue, 22 May 2012 14:25:14 +0400 Message-ID: <20120522102444.6988.45434.stgit@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-nfs-owner@vger.kernel.org List-ID: This patch adds recall_lock hold to nfsd_forget_delegations() to protect nfsd_process_n_delegations() call. Also, looks like it would be better to collect delegations to some local on-stack list, and then unhash collected list. This split allows to simplify locking, because delegation traversing is protected by recall_lock, when delegation unhash is protected by client_mutex. Signed-off-by: Stanislav Kinsbursky --- fs/nfsd/nfs4state.c | 32 ++++++++++++++++++++++++-------- 1 files changed, 24 insertions(+), 8 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 21266c7..f004e61 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -2597,7 +2597,7 @@ out: return ret; } -static void nfsd_break_one_deleg(struct nfs4_delegation *dp) +static void nfsd_break_one_deleg(struct nfs4_delegation *dp, void *data) { /* We're assuming the state code never drops its reference * without first removing the lease. Since we're in this lease @@ -2633,7 +2633,7 @@ static void nfsd_break_deleg_cb(struct file_lock *fl) spin_lock(&recall_lock); fp->fi_had_conflict = true; list_for_each_entry(dp, &fp->fi_delegations, dl_perfile) - nfsd_break_one_deleg(dp); + nfsd_break_one_deleg(dp, NULL); spin_unlock(&recall_lock); } @@ -4694,7 +4694,7 @@ void nfsd_forget_openowners(u64 num) printk(KERN_INFO "NFSD: Forgot %d open owners", count); } -int nfsd_process_n_delegations(u64 num, void (*deleg_func)(struct nfs4_delegation *)) +int nfsd_process_n_delegations(u64 num, void (*deleg_func)(struct nfs4_delegation *, void *), void *data) { int i, count = 0; struct nfs4_file *fp, *fnext; @@ -4703,7 +4703,7 @@ int nfsd_process_n_delegations(u64 num, void (*deleg_func)(struct nfs4_delegatio for (i = 0; i < FILE_HASH_SIZE; i++) { list_for_each_entry_safe(fp, fnext, &file_hashtbl[i], fi_hash) { list_for_each_entry_safe(dp, dnext, &fp->fi_delegations, dl_perfile) { - deleg_func(dp); + deleg_func(dp, data); if (++count == num) return count; } @@ -4713,15 +4713,31 @@ int nfsd_process_n_delegations(u64 num, void (*deleg_func)(struct nfs4_delegatio return count; } +/* Called under the recall_lock spinlock. */ +static void +collect_delegation(struct nfs4_delegation *dp, void *data) +{ + struct list_head *list = data; + + list_move(&dp->dl_perfile, list); +} + void nfsd_forget_delegations(u64 num) { unsigned int count; + struct nfs4_delegation *dp, *dnext; + LIST_HEAD(unhash_list); - nfs4_lock_state(); - count = nfsd_process_n_delegations(num, unhash_delegation); - nfs4_unlock_state(); + spin_lock(&recall_lock); + count = nfsd_process_n_delegations(num, collect_delegation, &unhash_list); + spin_unlock(&recall_lock); printk(KERN_INFO "NFSD: Forgot %d delegations", count); + + nfs4_lock_state(); + list_for_each_entry_safe(dp, dnext, &unhash_list, dl_perfile) + unhash_delegation(dp); + nfs4_unlock_state(); } void nfsd_recall_delegations(u64 num) @@ -4730,7 +4746,7 @@ void nfsd_recall_delegations(u64 num) nfs4_lock_state(); spin_lock(&recall_lock); - count = nfsd_process_n_delegations(num, nfsd_break_one_deleg); + count = nfsd_process_n_delegations(num, nfsd_break_one_deleg, NULL); spin_unlock(&recall_lock); nfs4_unlock_state();