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From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
	Kirill Tkhai <ktkhai@virtuozzo.com>,
	axboe@kernel.dk, linux-block@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org,
	tytso@mit.edu, adilger.kernel@dilger.ca, ming.lei@redhat.com,
	osandov@fb.com, jthumshirn@suse.de, minwoo.im.dev@gmail.com,
	damien.lemoal@wdc.com, andrea.parri@amarulasolutions.com,
	hare@suse.com, tj@kernel.org, ajay.joshi@wdc.com,
	sagi@grimberg.me, dsterba@suse.com, chaitanya.kulkarni@wdc.com,
	bvanassche@acm.org, dhowells@redhat.com, asml.silence@gmail.com
Subject: Re: [PATCH RFC 1/3] block: Add support for REQ_OP_ASSIGN_RANGE operation
Date: Thu, 19 Dec 2019 21:22:36 -0500	[thread overview]
Message-ID: <yq1a77nag7n.fsf@oracle.com> (raw)
In-Reply-To: <20191220015338.GB7473@magnolia> (Darrick J. Wong's message of "Thu, 19 Dec 2019 17:53:39 -0800")


Darrick,

[Anchor]

> What happens if you anchor and then try to read the results?  IO
> error?

Depends on the device. Typically you get the same results as UNMAP.

Anchoring is essentially a way to preallocate blocks on a thinly
provisioned device. If you then run out of actual storage capacity you
won't get a write failure writing to those LBAs. It is intended to
protect block ranges that do not tolerate write failures (journals,
metadata).

-- 
Martin K. Petersen	Oracle Linux Engineering

  reply	other threads:[~2019-12-20  2:23 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-10 16:56 [PATCH RFC 0/3] block,ext4: Introduce REQ_OP_ASSIGN_RANGE to reflect extents allocation in block device internals Kirill Tkhai
2019-12-10 16:56 ` [PATCH RFC 1/3] block: Add support for REQ_OP_ASSIGN_RANGE operation Kirill Tkhai
2019-12-19  3:03   ` Martin K. Petersen
2019-12-19 11:07     ` Kirill Tkhai
2019-12-19 22:03       ` Chaitanya Kulkarni
2019-12-19 22:37       ` Martin K. Petersen
2019-12-20  1:53         ` Darrick J. Wong
2019-12-20  2:22           ` Martin K. Petersen [this message]
2019-12-20 11:55         ` Kirill Tkhai
2019-12-21 18:54           ` Martin K. Petersen
2019-12-23  8:51             ` Kirill Tkhai
2020-01-07  3:24               ` Martin K. Petersen
2020-01-07 13:59                 ` Kirill Tkhai
2020-01-08  2:49                   ` Martin K. Petersen
2020-01-09  9:43                     ` Kirill Tkhai
2019-12-10 16:56 ` [PATCH RFC 2/3] loop: Forward REQ_OP_ASSIGN_RANGE into fallocate(0) Kirill Tkhai
2019-12-10 16:56 ` [PATCH RFC 3/3] ext4: Notify block device about fallocate(0)-assigned blocks Kirill Tkhai
2019-12-11 12:55   ` [PATCH RFC v2 " Kirill Tkhai
2019-12-11  7:42 ` [PATCH RFC 0/3] block,ext4: Introduce REQ_OP_ASSIGN_RANGE to reflect extents allocation in block device internals Chaitanya Kulkarni
2019-12-11  8:50   ` Kirill Tkhai
2019-12-17 14:16 ` Kirill Tkhai

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