From patchwork Wed Feb 18 07:36:59 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexey Dobriyan X-Patchwork-Id: 5842851 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id AEDD89F37F for ; Wed, 18 Feb 2015 07:37:28 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id DE78920219 for ; Wed, 18 Feb 2015 07:37:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F037F200ED for ; Wed, 18 Feb 2015 07:37:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751876AbbBRHhD (ORCPT ); Wed, 18 Feb 2015 02:37:03 -0500 Received: from mail-wg0-f43.google.com ([74.125.82.43]:52304 "EHLO mail-wg0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751230AbbBRHhB (ORCPT ); Wed, 18 Feb 2015 02:37:01 -0500 Received: by mail-wg0-f43.google.com with SMTP id z12so26951701wgg.2; Tue, 17 Feb 2015 23:36:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=B8jZrL18Vyx6A2Zah6wKbDICiR8LRrlHIab1wCHKbfo=; b=q2FDB6cVcMlnu6aSjifjkm23lnq8/hemUnPAYE0030mt7daJiMf4Er8d5v+stjUYbO eh1T0QxOrJJYG+20Ypw/3x7ETqN5Y3bkNmGTbTt06jZ4PT5bwW7yb6dxGPJJ21EnZoOz dmRu6BGQhMOdk+P+X+Rdrue7kQwKrYOSBjEKHB4ccf/hb0hkT/6qK30aoi9BaFdhqAHt Fthec5hD/5lCbGa1a/m/y9KuJIWm5PMtp1j2wiymLz+/D5pOnvD82dg0GgWCaHEFHQAn J1EYP8js1Uf4kbbcAZ2ErlTvPHkVi3st8Fga/Z6OSdeJGk+PXUqLRq5P9FCvXuOJyuLe XYFw== X-Received: by 10.194.240.164 with SMTP id wb4mr68537065wjc.66.1424245019746; Tue, 17 Feb 2015 23:36:59 -0800 (PST) Received: from p183.telecom.by (nat4-minsk-pool-46-53-177-222.telecom.by. [46.53.177.222]) by mx.google.com with ESMTPSA id eb10sm27994797wib.13.2015.02.17.23.36.58 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 17 Feb 2015 23:36:59 -0800 (PST) Date: Wed, 18 Feb 2015 10:36:59 +0300 From: Alexey Dobriyan To: Jan Kara Cc: akpm@linux-foundation.org, viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, swhiteho@redhat.com, cluster-devel@redhat.com Subject: [PATCH v2] fs: record task name which froze superblock Message-ID: <20150218073658.GB1752@p183.telecom.by> References: <20150214185524.GA16579@p183.telecom.by> <20150216093852.GB4749@quack.suse.cz> <20150218073455.GA1752@p183.telecom.by> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20150218073455.GA1752@p183.telecom.by> User-Agent: Mutt/1.5.22 (2013-10-16) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-6.0 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, RCVD_IN_SORBS_WEB, T_DKIM_INVALID, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Freezing and thawing are separate system calls, task which is supposed to thaw filesystem/superblock can disappear due to crash or not thaw due to a bug. Record at least task name (we can't take task_struct reference) to make support engineer's life easier. Hopefully 16 bytes per superblock isn't much. Signed-off-by: Alexey Dobriyan --- fs/block_dev.c | 12 ++++++++---- fs/ioctl.c | 22 ++++++++++++++++------ fs/super.c | 2 ++ include/linux/fs.h | 2 ++ 4 files changed, 28 insertions(+), 10 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -227,9 +227,11 @@ struct super_block *freeze_bdev(struct block_device *bdev) sb = get_active_super(bdev); if (!sb) goto out; - if (sb->s_op->freeze_super) + if (sb->s_op->freeze_super) { error = sb->s_op->freeze_super(sb); - else + if (error == 0) + get_task_comm(sb->s_writers.freeze_comm, current); + } else error = freeze_super(sb); if (error) { deactivate_super(sb); @@ -267,9 +269,11 @@ int thaw_bdev(struct block_device *bdev, struct super_block *sb) if (!sb) goto out; - if (sb->s_op->thaw_super) + if (sb->s_op->thaw_super) { error = sb->s_op->thaw_super(sb); - else + if (error == 0) + memset(sb->s_writers.freeze_comm, 0, TASK_COMM_LEN); + } else error = thaw_super(sb); if (error) { bdev->bd_fsfreeze_count++; --- a/fs/ioctl.c +++ b/fs/ioctl.c @@ -518,6 +518,7 @@ static int ioctl_fioasync(unsigned int fd, struct file *filp, static int ioctl_fsfreeze(struct file *filp) { struct super_block *sb = file_inode(filp)->i_sb; + int rv; if (!capable(CAP_SYS_ADMIN)) return -EPERM; @@ -527,22 +528,31 @@ static int ioctl_fsfreeze(struct file *filp) return -EOPNOTSUPP; /* Freeze */ - if (sb->s_op->freeze_super) - return sb->s_op->freeze_super(sb); - return freeze_super(sb); + if (sb->s_op->freeze_super) { + rv = sb->s_op->freeze_super(sb); + if (rv == 0) + get_task_comm(sb->s_writers.freeze_comm, current); + } else + rv = freeze_super(sb); + return rv; } static int ioctl_fsthaw(struct file *filp) { struct super_block *sb = file_inode(filp)->i_sb; + int rv; if (!capable(CAP_SYS_ADMIN)) return -EPERM; /* Thaw */ - if (sb->s_op->thaw_super) - return sb->s_op->thaw_super(sb); - return thaw_super(sb); + if (sb->s_op->thaw_super) { + rv = sb->s_op->thaw_super(sb); + if (rv == 0) + memset(sb->s_writers.freeze_comm, 0, TASK_COMM_LEN); + } else + rv = thaw_super(sb); + return rv; } /* --- a/fs/super.c +++ b/fs/super.c @@ -1355,6 +1355,7 @@ int freeze_super(struct super_block *sb) * sees write activity when frozen is set to SB_FREEZE_COMPLETE. */ sb->s_writers.frozen = SB_FREEZE_COMPLETE; + get_task_comm(sb->s_writers.freeze_comm, current); up_write(&sb->s_umount); return 0; } @@ -1391,6 +1392,7 @@ int thaw_super(struct super_block *sb) out: sb->s_writers.frozen = SB_UNFROZEN; + memset(sb->s_writers.freeze_comm, 0, TASK_COMM_LEN); smp_wmb(); wake_up(&sb->s_writers.wait_unfrozen); deactivate_locked_super(sb); --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1221,6 +1221,8 @@ struct sb_writers { int frozen; /* Is sb frozen? */ wait_queue_head_t wait_unfrozen; /* queue for waiting for sb to be thawed */ + /* who froze superblock and forgot to thaw it */ + char freeze_comm[16]; #ifdef CONFIG_DEBUG_LOCK_ALLOC struct lockdep_map lock_map[SB_FREEZE_LEVELS]; #endif