From patchwork Tue Jun 28 20:46:09 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andreas Gruenbacher X-Patchwork-Id: 12898929 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C02D7CCA479 for ; Tue, 28 Jun 2022 20:46:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231203AbiF1UqZ (ORCPT ); Tue, 28 Jun 2022 16:46:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33118 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230307AbiF1UqW (ORCPT ); Tue, 28 Jun 2022 16:46:22 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 4D3F22A422 for ; Tue, 28 Jun 2022 13:46:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1656449180; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=etd/HiWPRFylPp9B1UP6EMuDHvBVBKKMEBDyPqA1sCk=; b=aLACLbjOYVIwb1WKD/PZKpEyzi1F1vsW4B3wBinAs6PCmj21O/CFMmG9sugHfg+V4ibx6W tcatHRTVLxEV3JCCi957Hw6+g/UGd9iksGVoiR4bvLr/Mxm8Pt1e2Tk8rhXZ+gfaznkolj dhWCkKquJn9EZlMZbYxQoXlTuomzC8o= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-448-6--e8s4GMk2NY6qk63AJOQ-1; Tue, 28 Jun 2022 16:46:17 -0400 X-MC-Unique: 6--e8s4GMk2NY6qk63AJOQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id DB886294EDD1; Tue, 28 Jun 2022 20:46:16 +0000 (UTC) Received: from max.localdomain (unknown [10.40.193.19]) by smtp.corp.redhat.com (Postfix) with ESMTP id EDB88404E4C8; Tue, 28 Jun 2022 20:46:15 +0000 (UTC) From: Andreas Gruenbacher To: cluster-devel@redhat.com Cc: Andreas Gruenbacher , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, "Eric W. Biederman" Subject: [PATCH 3/5] gfs2: Add GL_NOPID flag for process-independent glock holders Date: Tue, 28 Jun 2022 22:46:09 +0200 Message-Id: <20220628204611.651126-4-agruenba@redhat.com> In-Reply-To: <20220628204611.651126-1-agruenba@redhat.com> References: <20220628204611.651126-1-agruenba@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Add a GL_NOPID flag to indicate that once a glock holder has been acquired, it won't be associated with the current process anymore. This is useful for iopen and flock glocks which are associated with open files, as well as journal glock holders and similar which are associated with the filesystem. Once GL_NOPID is used for all applicable glocks (see the next patches), processes will no longer be falsely reported as holding glocks which they are not actually holding in the glocks dump file. Unlike before, when a process is reported as having "(ended)", this will indicate an actual bug. Signed-off-by: Andreas Gruenbacher --- fs/gfs2/glock.c | 41 +++++++++++++++++++++++++++++++---------- fs/gfs2/glock.h | 1 + 2 files changed, 32 insertions(+), 10 deletions(-) diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index aa35f5d4eb54..480b3d2b00e8 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -1465,6 +1465,15 @@ void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...) va_end(args); } +static inline bool pid_is_meaningful(const struct gfs2_holder *gh) +{ + if (!(gh->gh_flags & GL_NOPID)) + return true; + if (gh->gh_state == LM_ST_UNLOCKED) + return true; + return false; +} + /** * add_to_queue - Add a holder to the wait queue (but look for recursion) * @gh: the holder structure to add @@ -1501,10 +1510,17 @@ __acquires(&gl->gl_lockref.lock) } list_for_each_entry(gh2, &gl->gl_holders, gh_list) { - if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid && - (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK) && - !test_bit(HIF_MAY_DEMOTE, &gh2->gh_iflags))) - goto trap_recursive; + if (likely(gh2->gh_owner_pid != gh->gh_owner_pid)) + continue; + if (gh->gh_gl->gl_ops->go_type == LM_TYPE_FLOCK) + continue; + if (test_bit(HIF_MAY_DEMOTE, &gh2->gh_iflags)) + continue; + if (!pid_is_meaningful(gh2)) + continue; + goto trap_recursive; + } + list_for_each_entry(gh2, &gl->gl_holders, gh_list) { if (try_futile && !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) { fail: @@ -2319,19 +2335,24 @@ static const char *hflags2str(char *buf, u16 flags, unsigned long iflags) static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh, const char *fs_id_buf) { - struct task_struct *gh_owner = NULL; + const char *comm = "(none)"; + pid_t owner_pid = 0; char flags_buf[32]; rcu_read_lock(); - if (gh->gh_owner_pid) + if (pid_is_meaningful(gh)) { + struct task_struct *gh_owner; + + comm = "(ended)"; + owner_pid = pid_nr(gh->gh_owner_pid); gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID); + if (gh_owner) + comm = gh_owner->comm; + } gfs2_print_dbg(seq, "%s H: s:%s f:%s e:%d p:%ld [%s] %pS\n", fs_id_buf, state2str(gh->gh_state), hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags), - gh->gh_error, - gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1, - gh_owner ? gh_owner->comm : "(ended)", - (void *)gh->gh_ip); + gh->gh_error, (long)owner_pid, comm, (void *)gh->gh_ip); rcu_read_unlock(); } diff --git a/fs/gfs2/glock.h b/fs/gfs2/glock.h index c0ae9100a0bc..e764ebeba54c 100644 --- a/fs/gfs2/glock.h +++ b/fs/gfs2/glock.h @@ -91,6 +91,7 @@ enum { #define GL_ASYNC 0x0040 #define GL_EXACT 0x0080 #define GL_SKIP 0x0100 +#define GL_NOPID 0x0200 #define GL_NOCACHE 0x0400 /*