[patch 04/19] xfs: untange SYNC_WAIT and SYNC_TRYLOCK meanings for xfs_qm_dqflush

[Ben Myers]

On Tue, Dec 06, 2011 at 04:58:10PM -0500, Christoph Hellwig wrote:
> Only skip pinned dquots if SYNC_TRYLOCK is specified, and adjust the callers
> to keep the behaviour unchanged.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> Reviewed-by: Dave Chinner <dchinner at redhat.com>

s/untange/untangle  in the subject line.

> ---
>  fs/xfs/xfs_dquot.c      |    2 +-
>  fs/xfs/xfs_dquot_item.c |    2 +-
>  fs/xfs/xfs_qm.c         |    2 +-
>  3 files changed, 3 insertions(+), 3 deletions(-)
> 
> Index: xfs/fs/xfs/xfs_dquot.c
> ===================================================================
> --- xfs.orig/fs/xfs/xfs_dquot.c	2011-11-05 08:54:01.729993938 +0100
> +++ xfs/fs/xfs/xfs_dquot.c	2011-11-25 11:45:32.668742260 +0100
> @@ -1169,7 +1169,7 @@ xfs_qm_dqflush(
>  	 * If not dirty, or it's pinned and we are not supposed to block, nada.
>  	 */
>  	if (!XFS_DQ_IS_DIRTY(dqp) ||
> -	    (!(flags & SYNC_WAIT) && atomic_read(&dqp->q_pincount) > 0)) {
> +	    ((flags & SYNC_TRYLOCK) && atomic_read(&dqp->q_pincount) > 0)) {

There is a SYNC_WAIT at the bottom of xfs_qm_dqflush.  Should it be
modified too?

>  		xfs_dqfunlock(dqp);
>  		return 0;
>  	}
> Index: xfs/fs/xfs/xfs_dquot_item.c
> ===================================================================
> --- xfs.orig/fs/xfs/xfs_dquot_item.c	2011-11-25 11:43:25.269432441 +0100
> +++ xfs/fs/xfs/xfs_dquot_item.c	2011-11-25 11:45:32.668742260 +0100
> @@ -133,7 +133,7 @@ xfs_qm_dquot_logitem_push(
>  	 * lock without sleeping, then there must not have been
>  	 * anyone in the process of flushing the dquot.
>  	 */
> -	error = xfs_qm_dqflush(dqp, 0);
> +	error = xfs_qm_dqflush(dqp, SYNC_TRYLOCK);
>  	if (error)
>  		xfs_warn(dqp->q_mount, "%s: push error %d on dqp %p",
>  			__func__, error, dqp);
> Index: xfs/fs/xfs/xfs_qm.c
> ===================================================================
> --- xfs.orig/fs/xfs/xfs_qm.c	2011-11-19 20:14:00.400421363 +0100
> +++ xfs/fs/xfs/xfs_qm.c	2011-11-25 11:45:32.672075575 +0100
> @@ -1661,7 +1661,7 @@ xfs_qm_quotacheck(
>  	 * successfully.
>  	 */
>  	if (!error)
> -		error = xfs_qm_dqflush_all(mp, 0);
> +		error = xfs_qm_dqflush_all(mp, SYNC_TRYLOCK);
>  
>  	/*
>  	 * We can get this error if we couldn't do a dquot allocation inside

from xfs_qm_dqreclaim_one:
	/*
	 * We flush it delayed write, so don't bother
	 * releasing the freelist lock.
	 */
	error = xfs_qm_dqflush(dqp, 0); 

Should that also be changed to SYNC_TRYLOCK?

SYNC_TRYLOCK also has meaning for xfs_qm_sync().  Maybe the intention
was that SYNC_TRYLOCK would be used with xfs_qm_sync, and SYNC_WAIT with
xfs_qm_dqflush?

-Ben