Subject: Re: [RFC PATCH v1 00/30] fs: inode->i_version rework and optimization
To: Jeff Layton <jlayton@redhat.com>,
        "J. Bruce Fields" <bfields@fieldses.org>
References: <20170320214327.GA5098@fieldses.org>
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Cc: Jan Kara <jack@suse.cz>, Christoph Hellwig <hch@infradead.org>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-nfs@vger.kernel.org, linux-ext4@vger.kernel.org,
        linux-btrfs@vger.kernel.org, linux-xfs@vger.kernel.org
From: Boaz Harrosh <openosd@gmail.com>
Message-ID: <42bec37f-670c-3ea1-f2aa-7cecd619ad7e@gmail.com>
Date: Fri, 31 Mar 2017 00:11:11 +0300
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On 03/30/2017 09:35 PM, Jeff Layton wrote:
<>
> Yeah, I imagine we'd need a on-disk change for this unless there's
> something already present that we could use in place of a crash counter.
> 

Perhaps we can use s_mtime and/or s_wtime in some way, I'm not sure
what is a parallel for that in xfs.
	s_mtime - time-of-last mount 
	s_wtime - time-of-last mount, umount, freez, unfreez, remount, ...
Of course you'll need a per FS vector to access that.

But this will need some math foo to get the bits compacted correctly
just a thought.

Thanks
Boaz