All of lore.kernel.org
 help / color / mirror / Atom feed
From: Dave Chinner <david@fromorbit.com>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: linux-xfs@vger.kernel.org, hch@infradead.org
Subject: Re: [PATCH 3/5] xfs: separate the dqrele_all inode grab logic from xfs_inode_walk_ag_grab
Date: Tue, 1 Jun 2021 10:20:23 +1000	[thread overview]
Message-ID: <20210601002023.GY664593@dread.disaster.area> (raw)
In-Reply-To: <162250086766.490412.9229536536315438431.stgit@locust>

On Mon, May 31, 2021 at 03:41:07PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
> 
> Disentangle the dqrele_all inode grab code from the "generic" inode walk
> grabbing code, and and use the opportunity to document why the dqrele
> grab function does what it does.
> 
> Since dqrele_all is the only user of XFS_ICI_NO_TAG, rename it to
> something more specific for what we're doing.
> 
> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> ---
>  fs/xfs/xfs_icache.c |   64 ++++++++++++++++++++++++++++++++++++++++++++++++---
>  fs/xfs/xfs_icache.h |    4 ++-
>  2 files changed, 62 insertions(+), 6 deletions(-)
> 
> 
> diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
> index 34b8b5fbd60d..5501318b5db0 100644
> --- a/fs/xfs/xfs_icache.c
> +++ b/fs/xfs/xfs_icache.c
> @@ -26,6 +26,8 @@
>  
>  #include <linux/iversion.h>
>  
> +static bool xfs_dqrele_inode_grab(struct xfs_inode *ip);
> +

Just mov the function higher up in the file rather than add forward
declarations....

>  /*
>   * Allocate and initialise an xfs_inode.
>   */
> @@ -765,6 +767,22 @@ xfs_inode_walk_ag_grab(
>  	return false;
>  }
>  
> +static inline bool
> +xfs_grabbed_for_walk(
> +	int			tag,
> +	struct xfs_inode	*ip,
> +	int			iter_flags)
> +{
> +	switch (tag) {
> +	case XFS_ICI_BLOCKGC_TAG:
> +		return xfs_inode_walk_ag_grab(ip, iter_flags);
> +	case XFS_ICI_DQRELE_NONTAG:
> +		return xfs_dqrele_inode_grab(ip);
> +	default:
> +		return false;
> +	}
> +}

Not really a fan of this XFS_ICI_DQRELE_NONTAG rename. It kinda
smears caller context across the walk API. We really have two
different things here - we want a tagless lookup, and we want a
dquot specific grab function.

This API change just means we're going to have to rename the "no
tag" lookup yet again when we need some other non tag-based lookup.

And I think this is redundant, because....

> +/* Decide if we want to grab this inode to drop its dquots. */
> +static bool
> +xfs_dqrele_inode_grab(
> +	struct xfs_inode	*ip)
> +{
> +	bool			ret = false;
> +
> +	ASSERT(rcu_read_lock_held());
> +
> +	/* Check for stale RCU freed inode */
> +	spin_lock(&ip->i_flags_lock);
> +	if (!ip->i_ino)
> +		goto out_unlock;
> +
> +	/*
> +	 * Skip inodes that are anywhere in the reclaim machinery because we
> +	 * drop dquots before tagging an inode for reclamation.
> +	 */
> +	if (ip->i_flags & (XFS_IRECLAIM | XFS_IRECLAIMABLE))
> +		goto out_unlock;
> +
> +	/*
> +	 * The inode looks alive; try to grab a VFS reference so that it won't
> +	 * get destroyed.  If we got the reference, return true to say that
> +	 * we grabbed the inode.
> +	 *
> +	 * If we can't get the reference, then we know the inode had its VFS
> +	 * state torn down and hasn't yet entered the reclaim machinery.  Since
> +	 * we also know that dquots are detached from an inode before it enters
> +	 * reclaim, we can skip the inode.
> +	 */
> +	ret = igrab(VFS_I(ip)) != NULL;
> +
> +out_unlock:
> +	spin_unlock(&ip->i_flags_lock);
> +	return ret;
> +}

This is basically just duplication of xfs_inode_walk_ag_grab()
without the XFS_INODE_WALK_INEW_WAIT check in it. At this point I
just don't see a reason for this function or the
XFS_ICI_DQRELE_NONTAG rename just to use this grab function...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

  reply	other threads:[~2021-06-01  0:20 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-31 22:40 [PATCHSET v2 0/5] xfs: clean up quotaoff inode walks Darrick J. Wong
2021-05-31 22:40 ` [PATCH 1/5] xfs: move the quotaoff dqrele inode walk into xfs_icache.c Darrick J. Wong
2021-05-31 22:41 ` [PATCH 2/5] xfs: detach inode dquots at the end of inactivation Darrick J. Wong
2021-06-01  0:09   ` Dave Chinner
2021-05-31 22:41 ` [PATCH 3/5] xfs: separate the dqrele_all inode grab logic from xfs_inode_walk_ag_grab Darrick J. Wong
2021-06-01  0:20   ` Dave Chinner [this message]
2021-06-01 19:50     ` Darrick J. Wong
2021-06-01 21:40       ` Dave Chinner
2021-06-01 23:15         ` Darrick J. Wong
2021-05-31 22:41 ` [PATCH 4/5] xfs: drop inactive dquots before inactivating inodes Darrick J. Wong
2021-06-01  0:35   ` Dave Chinner
2021-06-01 19:53     ` Darrick J. Wong
2021-05-31 22:41 ` [PATCH 5/5] xfs: move xfs_inew_wait call into xfs_dqrele_inode Darrick J. Wong
2021-06-01  0:47   ` Dave Chinner

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210601002023.GY664593@dread.disaster.area \
    --to=david@fromorbit.com \
    --cc=djwong@kernel.org \
    --cc=hch@infradead.org \
    --cc=linux-xfs@vger.kernel.org \
    --subject='Re: [PATCH 3/5] xfs: separate the dqrele_all inode grab logic from xfs_inode_walk_ag_grab' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.