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From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Matteo Croce <mcroce@linux.microsoft.com>
Cc: linux-ext4@vger.kernel.org
Subject: Re: discard and data=writeback
Date: Wed, 23 Dec 2020 13:12:24 -0500	[thread overview]
Message-ID: <X+OIiNOGKmbwITC3@mit.edu> (raw)
In-Reply-To: <CAFnufp1X1B27Dfr_0DUaBNkKhSGmUjBAvPT+tMoQ8JW6b+q03w@mail.gmail.com>

On Wed, Dec 23, 2020 at 01:47:33AM +0100, Matteo Croce wrote:
> As an extra test I extracted the archive with data=ordered, remounted
> with data=writeback and timed the rm -rf and viceversa.
> The mount option is the one that counts, the one using during
> extraction doesn't matter.

Hmm... that's really surprising.  At this point, the only thing I can
suggest is to try using blktrace to see what's going on at the block
layer when the I/O's and discard requests are being submitted.  If
there are no dirty blocks in the page cache, I don't see how
data=ordered vs data=writeback would make a difference to how mount -o
discard processing would take place.

Cheers,

					- Ted

  reply	other threads:[~2020-12-23 18:13 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-18 18:40 discard and data=writeback Matteo Croce
2020-12-21  3:04 ` Theodore Y. Ts'o
2020-12-22 14:59   ` Matteo Croce
2020-12-22 16:34     ` Theodore Y. Ts'o
2020-12-22 22:53       ` Andreas Dilger
2020-12-23  1:25         ` Matteo Croce
2020-12-23  0:47       ` Matteo Croce
2020-12-23 18:12         ` Theodore Y. Ts'o [this message]
2020-12-23 18:59           ` Matteo Croce
2020-12-24  3:16             ` Theodore Y. Ts'o
2020-12-24 10:53               ` Matteo Croce
     [not found] <CGME20201229054143epcms2p15ae3cce43bb3c503adf94528f354ba78@epcms2p1>
2020-12-29  5:41 ` Daejun Park
2020-12-29 13:42   ` Matteo Croce

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