From: Christoph Hellwig <hch@infradead.org>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: Lukas Herbolt <lukas@herbolt.com>,
yi.zhang@huaweicloud.com, linux-xfs@vger.kernel.org
Subject: Re: [PATCH v3] xfs: add FALLOC_FL_WRITE_ZEROES to XFS code base
Date: Thu, 30 Oct 2025 00:27:29 -0700 [thread overview]
Message-ID: <aQMTYZTZIA2LF4h0@infradead.org> (raw)
In-Reply-To: <20251029182255.GK3356773@frogsfrogsfrogs>
On Wed, Oct 29, 2025 at 11:22:55AM -0700, Darrick J. Wong wrote:
> > + if (mode & FALLOC_FL_WRITE_ZEROES) {
> > + if (xfs_is_cow_inode(ip) || !bdev_write_zeroes_unmap_sectors(
>
> xfs_is_cow_inode() only tells us if the inode is capable of doing out of
> place writes. Why would a regular reflinked inode be ineligible for
> WRITE_ZEROES?
Yes, this shoyuld be xfs_is_always_cow_inode.
> I don't understand why this bdev_write_zeroes_unmap_sectors check is
> here and not in xfs_alloc_file_space. Shouldn't other callers of
> xfs_alloc_file_space be restricted from passing in XFS_BMAPI_ZERO if the
> block device doesn't support unmap_sectors?
Othere callers are fine with the software fallback for the block zeroing
helpers. But this is a good question that should probably be documented
in a comment.
next prev parent reply other threads:[~2025-10-30 7:27 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-21 14:17 [PATCH 0/2] Add FL_WRITE_ZEROES to XFS, fix krealloc on xfs_uuid_table Lukas Herbolt
2025-10-21 14:17 ` [PATCH] xfs: add FALLOC_FL_WRITE_ZEROES to XFS code base Lukas Herbolt
2025-10-21 15:55 ` Darrick J. Wong
2025-10-22 5:00 ` Christoph Hellwig
2025-10-22 7:13 ` Zhang Yi
2025-10-22 7:15 ` Christoph Hellwig
2025-10-22 7:27 ` Zhang Yi
2025-10-29 17:53 ` [PATCH v3] " Lukas Herbolt
2025-10-29 18:22 ` Darrick J. Wong
2025-10-30 7:27 ` Christoph Hellwig [this message]
2025-11-12 21:02 ` [PATCH v4] " Lukas Herbolt
2025-11-13 6:59 ` Christoph Hellwig
2025-11-14 8:55 ` [PATCH v5] " Lukas Herbolt
2025-11-14 8:57 ` Christoph Hellwig
2025-11-14 16:44 ` Darrick J. Wong
2025-11-14 16:45 ` Christoph Hellwig
2025-11-18 9:05 ` lukas
2025-12-15 11:48 ` [PATCH v6] " Lukas Herbolt
2025-12-15 14:28 ` Christoph Hellwig
2025-10-30 7:29 ` [PATCH v3] " Christoph Hellwig
2025-10-21 14:17 ` [PATCH 2/2] xfs: Remove WARN_ONCE if xfs_uuid_table grows over 2x PAGE_SIZE Lukas Herbolt
2025-10-21 15:56 ` Darrick J. Wong
2025-10-21 22:02 ` Dave Chinner
2025-10-26 17:49 ` lukas
2025-10-22 4:53 ` Christoph Hellwig
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