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

[Raghavendra D Prabhu <rprabhu@wnohang.net>]

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Hi,

Apparently calling xfs_syncd_stop from xfs_sync_worker doesn't 
work well; So I have moved it to xfs_bwrite; though with this I 
noticed a 2-3 log force errors at flush and umount. Here is the 
revised version. 


 From e202a7d76d8209fd3eb70158719a65034a409168 Mon Sep 17 00:00:00 2001
Message-Id: <e202a7d76d8209fd3eb70158719a65034a409168.1336390891.git.rprabhu@wnohang.net>
From: Raghavendra D Prabhu <rprabhu@wnohang.net>
Date: Mon, 7 May 2012 17:07:49 +0530
Subject: [PATCH] Stop periodic syncing if filesystem is already shutdown.

This is to prevent xfs_log_force from running ad-infinitum (due to xfs_sync) till umount if the disk has been forcefully unplugged.

This is to prevent messages like these from being displayed repeatedly.

[ 3873.009329] XFS (sdb3): xfs_log_force: error 5 returned.

Note, that even after xfs_do_force_shutdown has been called, xfs_log_force
doesn't stop till the filesystem has been unmounted (and it keeps printing
"error 5 returned" to kernel log).

To simulate it, mount an xfs filesystem located on external disk, and then pull
the power to the disk (non-usb powered disk).

Tested it on latest linus tree.
Now, the kernel log looks,

[  268.307303] XFS (sdb2): xfs_do_force_shutdown(0x1) called from line 1031 of file fs/xfs/xfs_buf.c.  Return address = 0xffffffff8127c13a
[  268.307318] XFS (sdb2): I/O Error Detected. Shutting down filesystem
[  268.307323] XFS (sdb2): Please umount the filesystem and rectify the problem(s)

Since, xfs_syncd_stop is already called in xfs_bwrite; the message is not
printed; also added checks in xfs_sync_worker and xfs_flush_worker to return in
this case (if they have already been entered).

Signed-off-by: Raghavendra D Prabhu <rprabhu@wnohang.net>
Tested-by: Raghavendra D Prabhu <rprabhu@wnohang.net>
  ---
---
  fs/xfs/xfs_buf.c  |    1 +
  fs/xfs/xfs_sync.c |   10 ++++++++++
  2 files changed, 11 insertions(+)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 6819b51..7bdf018 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1029,6 +1029,7 @@ xfs_bwrite(
  	if (error) {
  		xfs_force_shutdown(bp->b_target->bt_mount,
  				   SHUTDOWN_META_IO_ERROR);
+		xfs_syncd_stop(bp->b_target->bt_mount);
  	}
  	return error;
  }
diff --git a/fs/xfs/xfs_sync.c b/fs/xfs/xfs_sync.c
index 205ebcb..79745a5 100644
--- a/fs/xfs/xfs_sync.c
+++ b/fs/xfs/xfs_sync.c
@@ -460,6 +460,11 @@ xfs_sync_worker(
  					struct xfs_mount, m_sync_work);
  	int		error;
  
+	if (!xfs_fs_writable(mp)) {
+		xfs_err(mp, "Filesystem not writable / already shutdown.");
+		return;
+	}
+
  	if (!(mp->m_flags & XFS_MOUNT_RDONLY)) {
  		/* dgc: errors ignored here */
  		if (mp->m_super->s_frozen == SB_UNFROZEN &&
@@ -551,6 +556,11 @@ 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.");
+		return;
+	}
+
  	xfs_sync_data(mp, SYNC_TRYLOCK);
  	xfs_sync_data(mp, SYNC_TRYLOCK | SYNC_WAIT);
  }
-- 
1.7.10.1



* On Mon, May 07, 2012 at 02:44:07PM +0530, raghu.prabhu13@gmail.com <raghu.prabhu13@gmail.com> wrote:
>From: Raghavendra D Prabhu <rprabhu@wnohang.net>
>
>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.
>
>==========================================
>[ 3816.416570] XFS (sdb3): xfs_do_force_shutdown(0x1) called from line 1031 of file fs/xfs/xfs_buf.c.  Return address = 0xffffffff8127c13a
>[ 3816.416586] XFS (sdb3): I/O Error Detected. Shutting down filesystem
>[ 3816.416592] XFS (sdb3): Please umount the filesystem and rectify the problem(s)
>[ 3842.941953] XFS (sdb3): xfs_log_force: error 5 returned.
>[ 3873.009329] XFS (sdb3): xfs_log_force: error 5 returned.
>[ 3878.913310] XFS (sdb3): xfs_log_force: error 5 returned.
>[ 3878.913322] XFS (sdb3): xfs_do_force_shutdown(0x1) called from line 1031 of file fs/xfs/xfs_buf.c.  Return address = 0xffffffff8127c13a
>[ 3878.913350] XFS (sdb3): xfs_log_force: error 5 returned.
>[ 3878.913362] XFS (sdb3): xfs_log_force: error 5 returned.
>===========================================
>
>Note, that even after xfs_do_force_shutdown has been called, xfs_log_force
>doesn't stop till the filesystem has been unmounted (and it keeps printing
>"error 5 returned" to kernel log).
>
>To simulate it, mount an xfs filesystem located on external disk, and then pull
>the power to the disk (non-usb powered disk).
>
>Tested it on latest linus tree.
>Now, the kernel log looks,
>
>[ 2477.305280] XFS (sdc3): xfs_do_force_shutdown(0x1) called from line 1031 of file fs/xfs/xfs_buf.c.  Return address = 0xffffffff8127c13a
>[ 2477.305295] XFS (sdc3): I/O Error Detected. Shutting down filesystem
>[ 2477.305300] XFS (sdc3): Please umount the filesystem and rectify the problem(s)
>[ 2477.305588] XFS (sdc2): xfs_do_force_shutdown(0x1) called from line 1031 of file fs/xfs/xfs_buf.c.  Return address = 0xffffffff8127c13a
>[ 2477.305600] XFS (sdc2): I/O Error Detected. Shutting down filesystem
>[ 2477.305604] XFS (sdc2): Please umount the filesystem and rectify the problem(s)
>[ 2487.810718] XFS (sdc3): xfs_log_force: error 5 returned.
>[ 2487.810729] XFS (sdc3): xfs_do_force_shutdown(0x1) called from line 1031 of file fs/xfs/xfs_buf.c.  Return address = 0xffffffff8127c13a
>[ 2487.812981] XFS (sdc2): xfs_log_force: error 5 returned.
>[ 2487.812991] XFS (sdc2): xfs_do_force_shutdown(0x1) called from line 1031 of file fs/xfs/xfs_buf.c.  Return address = 0xffffffff8127c13a
>[ 2489.420042] XFS (sdc3): Filesystem not writable / already shutdown.
>[ 2490.955438] XFS (sdc2): Filesystem not writable / already shutdown.
>
>Signed-off-by: Raghavendra D Prabhu <rprabhu@wnohang.net>
>Tested-by: Raghavendra D Prabhu <rprabhu@wnohang.net>
>---
> 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;
>+	}
>+
> 	if (!(mp->m_flags & XFS_MOUNT_RDONLY)) {
> 		/* 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);
> }
>-- 
>1.7.10.1
>
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Regards,
-- 
Raghavendra Prabhu
GPG Id : 0xD72BE977
Fingerprint: B93F EBCB 8E05 7039 CD3C A4B8 A616 DCA1 D72B E977
www: wnohang.net

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