Commit 1acd6831 authored Nov 05, 2012 by Stefan Behrens Committed by Josef Bacik Dec 12, 2012

Btrfs: avoid risk of a deadlock in btrfs_handle_error



Remove the attempt to cancel a running scrub or device replace
operation in btrfs_handle_error() because it adds the risk of
a deadlock. The only penalty of not canceling the operation is
that some I/O remains active until the procedure completes.
This is basically the same thing that happens to other tasks
that are running in user mode context, they are not affected
or stopped in btrfs_handle_error(), these tasks just need to
handle write errors correctly.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

parent aa1b8cd4

fs/btrfs/super.c

+10 −1

Original line number	Diff line number	Diff line
		@@ -116,7 +116,16 @@ static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
		if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
		sb->s_flags \|= MS_RDONLY;
		printk(KERN_INFO "btrfs is forced readonly\n");
		btrfs_scrub_cancel(fs_info);
		/*
		* Note that a running device replace operation is not
		* canceled here although there is no way to update
		* the progress. It would add the risk of a deadlock,
		* therefore the canceling is ommited. The only penalty
		* is that some I/O remains active until the procedure
		* completes. The next time when the filesystem is
		* mounted writeable again, the device replace
		* operation continues.
		*/
		// WARN_ON(1);
		}
		}

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