Re: [PATCH] Btrfs: don't delay inode ref updates during log replay

[Marc MERLIN <marc@merlins.org>]

Chris, you rule, I applied this to 3.16.7 and my problem went away.

Tested-By: Marc MERLIN <marc@merlins.org>

Happy new year! :)

Marc

On Wed, Dec 31, 2014 at 01:30:13PM -0500, Chris Mason wrote:
> Commit 1d52c78afbb (Btrfs: try not to ENOSPC on log replay) added a
> check to skip delayed inode updates during log replay because it
> confuses the enospc code.  But the delayed processing will end up
> skipping delayed refs from log replay because the inode itself wasn't
> put through the delayed code.
> 
> This can end up triggering a warning at commit time:
> 
> WARNING: CPU: 2 PID: 778 at fs/btrfs/delayed-inode.c:1410 btrfs_assert_delayed_root_empty+0x32/0x34()
> 
> Which is repeated for each commit because we never process the delayed ref.
> 
> The fix used here is to change btrfs_delayed_delete_inode_ref to return
> an error if we're current in log replay.  The caller will do the ref
> deletion immediately and everything will work properly.
> 
> This bug can cause lost files, whick fsck will find.  --repair on
> btrfs-progs 3.18 will fix them
> 
> Signed-off-by: Chris Mason <clm@fb.com>
> cc: stable@vger.kernel.org # v3.18 and any stable series that picked 1d52c78afbbf80b58299e076a159617d6b42fe3c
> 
> diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
> index 054577b..de4e70f 100644
> --- a/fs/btrfs/delayed-inode.c
> +++ b/fs/btrfs/delayed-inode.c
> @@ -1857,6 +1857,14 @@ int btrfs_delayed_delete_inode_ref(struct inode *inode)
>  {
>  	struct btrfs_delayed_node *delayed_node;
>  
> +	/*
> +	 * we don't do delayed inode updates during log recovery because it
> +	 * leads to enospc problems.  This means we also can't do
> +	 * delayed inode refs
> +	 */
> +	if (BTRFS_I(inode)->root->fs_info->log_root_recovering)
> +		return -EAGAIN;
> +
>  	delayed_node = btrfs_get_or_create_delayed_node(inode);
>  	if (IS_ERR(delayed_node))
>  		return PTR_ERR(delayed_node);
> --
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