xfs
[Top] [All Lists]

Re: Re: [PATCH] [PATCH] Stop periodic syncing if filesystem is already

To: Dave Chinner <david@xxxxxxxxxxxxx>
Subject: Re: Re: [PATCH] [PATCH] Stop periodic syncing if filesystem is already shutdown.
From: Raghavendra D Prabhu <raghu.prabhu13@xxxxxxxxx>
Date: Thu, 10 May 2012 01:37:46 +0530
Cc: xfs@xxxxxxxxxxx
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:subject:message-id:mail-followup-to:references :mime-version:content-type:content-disposition:in-reply-to :x-operating-system:x-editor:user-agent; bh=h2B73yLSVTMOvYpd/MCIEz1bNkJQEJit9kWyOhJlBIk=; b=HBnHV2bU+hLvFE/ia6LsBgiQcrkzGDoCNOdiP8zo4u9QMA38QYKcYK+I/9bCuNXa5e ogjV3qk6Zb+zS2wDS3WE+qL2/YfbBCEh1uNZkFfgW3BapqUKnCA+PCnnlQeXNizqSaN1 DIhWBNROAG1Jz0FVwsLBYqPCk5Ak/77dz/lIFhU/4/NIn/Pirg/G1ix1iFbose79p/vu HRAfP9W+63ftupVRImUPr+w8c4JNxop3mAEAOJaxtxlqMrwW7Poeui8NHpR9v6Snos7Y Mr4Nlwcitb9/pC1vkIXKjCwjBmntUkUz9tgxWgwoUhcNoDxCrboq3kEIocHPqF+R3mMZ QITw==
In-reply-to: <20120507235321.GD5091@dastard>
Mail-followup-to: Dave Chinner <david@xxxxxxxxxxxxx>, xfs@xxxxxxxxxxx
References: <a27cbce4f4b35c2a8aee1b58d88c22381fe70ccf.1336378182.git.rprabhu@xxxxxxxxxxx> <20120507235321.GD5091@dastard>
User-agent: Mutt/1.5.21 (2011-07-01)

Hi,


* On Tue, May 08, 2012 at 09:53:21AM +1000, Dave Chinner <david@xxxxxxxxxxxxx> 
wrote:
On Mon, May 07, 2012 at 02:44:07PM +0530, raghu.prabhu13@xxxxxxxxx wrote:
From: Raghavendra D Prabhu <rprabhu@xxxxxxxxxxx>

This is to prevent syncing from running ad-infinitum till umount if the disk 
has been forcefully unplugged.

This is to prevent messages like these from being displayed.
.....
---
 fs/xfs/xfs_sync.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/fs/xfs/xfs_sync.c b/fs/xfs/xfs_sync.c
index 205ebcb..7ec412c 100644
--- a/fs/xfs/xfs_sync.c
+++ b/fs/xfs/xfs_sync.c
@@ -460,6 +460,12 @@ xfs_sync_worker(
                                        struct xfs_mount, m_sync_work);
        int             error;

+       if (!xfs_fs_writable(mp)) {
+               xfs_err(mp, "Filesystem not writable / already shutdown.");
+               xfs_syncd_stop(mp);
+               return;
+       }
+

That is going to kill the xfssyncd on read only and frozen
filesystems as well as shutdowns, so this is certainly not correct.
The xfs_sync_worker should continue to run until the filesystem is
unmounted, even if it does nothing when it runs.

Yes, in the next patch I had sent -- http://article.gmane.org/gmane.comp.file-systems.xfs.general/45568 -- I removed xfs_syncd_stop from there and added it under xfs_bwrite. (PS: Adding xfs_syncd_stop in xfs_sync_worker was a very bad decision - it sent few of my kworkers to 'D' state and nearly corrupted that fs)



Indeed, all that is needed in xfs_sync_worker() is this:

-       if (!(mp->m_flags & XFS_MOUNT_RDONLY)) {
+       if (!xfs_fs_writable(mp)) {

and the error message won't appear. It fixes the problem for the
shutdown case, as well as handles frozen and read-only filesystems
correctly.
I realized from your earlier comment that, calling xfs_syncd_stop under xfs_bwrite won't be good either; so I was thinking of just checking for XFS_FORCED_SHUTDOWN(mp) in xfs_log_force and bailing out if already shutdown.

which should take care of xfs_sync_worker, xfs_flush_worker, xfs_iflush and xfs_unmountfs


    Does this sound good?


                /* dgc: errors ignored here */
                if (mp->m_super->s_frozen == SB_UNFROZEN &&
@@ -551,6 +557,12 @@ xfs_flush_worker(
        struct xfs_mount *mp = container_of(work,
                                        struct xfs_mount, m_flush_work);

+       if (!xfs_fs_writable(mp)) {
+               xfs_err(mp, "Filesystem not writable / already shutdown.");
+               xfs_syncd_stop(mp);
+               return;
+       }
+
        xfs_sync_data(mp, SYNC_TRYLOCK);
        xfs_sync_data(mp, SYNC_TRYLOCK | SYNC_WAIT);

This is not necessary, either, because xfs_sync_data() has shutdown
checks and xfs_flush_worker() should never be called on a shutdown
filesystem....
Yeah, I realized that (sent a patch after this http://article.gmane.org/gmane.comp.file-systems.xfs.general/45568).

Cheers,

Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx









Regards,
--
Raghavendra Prabhu
GPG Id : 0xD72BE977
Fingerprint: B93F EBCB 8E05 7039 CD3C A4B8 A616 DCA1 D72B E977
www: wnohang.net

Attachment: pgpXu1sxqmIHY.pgp
Description: PGP signature

<Prev in Thread] Current Thread [Next in Thread>