Re: [PATCH v2 0/9] fallocate: introduce FALLOC_FL_WRITE_ZEROES flag

[Zhang Yi <yi.zhang@huaweicloud.com>]

On 2025/6/23 18:46, Christian Brauner wrote:
> On Thu, 19 Jun 2025 19:17:57 +0800, Zhang Yi wrote:
>> From: Zhang Yi <yi.zhang@huawei.com>
>>
>> Changes since v1:
>>  - Rebase codes on 6.16-rc2.
>>  - Use max_{hw|user}_wzeroes_unmap_sectors queue limits instead of
>>    BLK_FEAT_WRITE_ZEROES_UNMAP feature to represent the status of the
>>    unmap write zeroes operation as Christoph and Darrick suggested. This
>>    redoes the first 5 patches, so remove all the reviewed-by tags,
>>    please review them again.
>>  - Simplify the description of FALLOC_FL_WRITE_ZEROES in patch 06 as
>>    Darrick suggested.
>>  - Revise the check order of FALLOC_FL_WRITE_ZEROES in patch 08 as
>>    Christoph suggested.
>> Changes since RFC v4:
>>  - Rebase codes on 6.16-rc1.
>>  - Add a new queue_limit flag, and change the write_zeroes_unmap sysfs
>>    interface to RW mode. User can disable the unmap write zeroes
>>    operation by writing '0' to it when the operation is slow.
>>  - Modify the documentation of write_zeroes_unmap sysfs interface as
>>    Martin suggested.
>>  - Remove the statx interface.
>>  - Make the bdev and ext4 don't allow to submit FALLOC_FL_WRITE_ZEROES
>>    if the block device does not enable the unmap write zeroes operation,
>>    it should return -EOPNOTSUPP.
>> Changes sicne RFC v3:
>>  - Rebase codes on 6.15-rc2.
>>  - Add a note in patch 1 to indicate that the unmap write zeros command
>>    is not always guaranteed as Christoph suggested.
>>  - Rename bdev_unmap_write_zeroes() helper and move it to patch 1 as
>>    Christoph suggested.
>>  - Introduce a new statx attribute flag STATX_ATTR_WRITE_ZEROES_UNMAP as
>>    Christoph and Christian suggested.
>>  - Exchange the order of the two patches that modified
>>    blkdev_fallocate() as Christoph suggested.
>> Changes since RFC v2:
>>  - Rebase codes on next-20250314.
>>  - Add support for nvme multipath.
>>  - Add support for NVMeT with block device backing.
>>  - Clear FALLOC_FL_WRITE_ZEROES if dm clear
>>    limits->max_write_zeroes_sectors.
>>  - Complement the counterpart userspace tools(util-linux and xfs_io)
>>    and tests(blktests and xfstests), please see below for details.
>> Changes since RFC v1:
>>  - Switch to add a new write zeroes operation, FALLOC_FL_WRITE_ZEROES,
>>    in fallocate, instead of just adding a supported flag to
>>    FALLOC_FL_ZERO_RANGE.
>>  - Introduce a new flag BLK_FEAT_WRITE_ZEROES_UNMAP to the block
>>    device's queue limit features, and implement it on SCSI sd driver,
>>    NVMe SSD driver and dm driver.
>>  - Implement FALLOC_FL_WRITE_ZEROES on both the ext4 filesystem and
>>    block device (bdev).
>>
>> [...]
> 
> If needed, the branch can be declared stable and thus be used as base
> for other work.
> 
> ---
> 
> Applied to the vfs-6.17.fallocate branch of the vfs/vfs.git tree.
> Patches in the vfs-6.17.fallocate branch should appear in linux-next soon.
> 
> Please report any outstanding bugs that were missed during review in a
> new review to the original patch series allowing us to drop it.
> 
> It's encouraged to provide Acked-bys and Reviewed-bys even though the
> patch has now been applied. If possible patch trailers will be updated.
> 
> Note that commit hashes shown below are subject to change due to rebase,
> trailer updates or similar. If in doubt, please check the listed branch.
> 
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
> branch: vfs-6.17.fallocate

Hi Christian,

I noticed that this patch series doesn't appear to be merged into this
branch. Just wondering if it might have been missed?

Best regards,
Yi.

> 
> [1/9] block: introduce max_{hw|user}_wzeroes_unmap_sectors to queue limits
>       https://git.kernel.org/vfs/vfs/c/2695a9b086fd
> [2/9] nvme: set max_hw_wzeroes_unmap_sectors if device supports DEAC bit
>       https://git.kernel.org/vfs/vfs/c/bf07c1180194
> [3/9] nvmet: set WZDS and DRB if device enables unmap write zeroes operation
>       https://git.kernel.org/vfs/vfs/c/a6c7ab5adcba
> [4/9] scsi: sd: set max_hw_wzeroes_unmap_sectors if device supports SD_ZERO_*_UNMAP
>       https://git.kernel.org/vfs/vfs/c/92372ed1cc88
> [5/9] dm: clear unmap write zeroes limits when disabling write zeroes
>       https://git.kernel.org/vfs/vfs/c/e383d550e716
> [6/9] fs: introduce FALLOC_FL_WRITE_ZEROES to fallocate
>       https://git.kernel.org/vfs/vfs/c/1ed1b5df86ec
> [7/9] block: factor out common part in blkdev_fallocate()
>       https://git.kernel.org/vfs/vfs/c/96433508c8c0
> [8/9] block: add FALLOC_FL_WRITE_ZEROES support
>       https://git.kernel.org/vfs/vfs/c/2b4e5f9b3eb9
> [9/9] ext4: add FALLOC_FL_WRITE_ZEROES support
>       https://git.kernel.org/vfs/vfs/c/51954e469396