From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.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: Sat, 21 Dec 2019 13:54:50 -0500 [thread overview]
Message-ID: <yq1pngh7blx.fsf@oracle.com> (raw)
In-Reply-To: <625c9ee4-bedb-ff60-845e-2d440c4f58aa@virtuozzo.com> (Kirill Tkhai's message of "Fri, 20 Dec 2019 14:55:09 +0300")
Kirill,
> One more thing to discuss. The new REQ_NOZERO flag won't be supported
> by many block devices (their number will be even less, than number of
> REQ_OP_WRITE_ZEROES supporters). Will this be a good thing, in case of
> we will be completing BLKDEV_ZERO_ALLOCATE bios in
> __blkdev_issue_write_zeroes() before splitting? I mean introduction of
> some flag in struct request_queue::limits. Completion of them with
> -EOPNOTSUPP in block devices drivers looks suboptimal for me.
We already have the NOFALLBACK flag to let the user make that decision.
If that flag is not specified, and I receive an allocate request for a
SCSI device that does not support ANCHOR, my expectation would be that I
would do a regular write same.
If it's a filesystem that is the recipient of the operation and not a
SCSI device, how to react would depend on how the filesystem handles
unwritten extents, etc.
--
Martin K. Petersen Oracle Linux Engineering
next prev parent reply other threads:[~2019-12-21 18:57 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
2019-12-20 11:55 ` Kirill Tkhai
2019-12-21 18:54 ` Martin K. Petersen [this message]
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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