From: Al Viro <viro@ZenIV.linux.org.uk>
To: Dave Chinner <david@fromorbit.com>
Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH V2] fs: don't scan the inode cache before SB_BORN is set
Date: Tue, 27 Mar 2018 08:24:45 +0100 [thread overview]
Message-ID: <20180327072445.GS30522@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20180327065756.GO18129@dastard>
On Tue, Mar 27, 2018 at 05:57:56PM +1100, Dave Chinner wrote:
> */
> + smp_rmb();
> + if (!(sb->s_flags & SB_BORN))
> + return 0;
> +
> if (sb->s_op && sb->s_op->nr_cached_objects)
> total_objects = sb->s_op->nr_cached_objects(sb, sc);
>
> @@ -1227,7 +1237,13 @@ mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
> sb = root->d_sb;
> BUG_ON(!sb);
> WARN_ON(!sb->s_bdi);
> +
> + /*
> + * Write barrier is for super_cache_count() to ensure it does not run
> + * until after the superblock is fully set up.
> + */
> sb->s_flags |= SB_BORN;
> + smp_wmb();
Umm... OK, I'm nearly asleep right now, but... shouldn't that be
if (check ->s_flags)
bugger off
smp_rmb();
loads
vs.
stores
smp_wmb();
store ->s_flags?
IOW, your barriers seem to be in the wrong places...
prev parent reply other threads:[~2018-03-27 7:24 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-26 4:35 [PATCH] fs: don't scan the inode cache before SB_ACTIVE is set Dave Chinner
2018-03-26 5:31 ` Al Viro
2018-03-26 5:51 ` Al Viro
2018-03-26 6:33 ` Dave Chinner
2018-03-26 6:55 ` Al Viro
2018-03-26 7:21 ` Dave Chinner
2018-03-27 6:57 ` [PATCH V2] fs: don't scan the inode cache before SB_BORN " Dave Chinner
2018-03-27 7:24 ` Al Viro [this message]
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