fsdax: remove zeroing code from dax_unshare_iter

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[ Upstream commit 95472274b6 ]

Remove the code in dax_unshare_iter that zeroes the destination memory
because it's not necessary.

If srcmap is unwritten, we don't have to do anything because that
unwritten extent came from the regular file mapping, and unwritten
extents cannot be shared.  The same applies to holes.

Furthermore, zeroing to unshare a mapping is just plain wrong because
unsharing means copy on write, and we should be copying data.

This is effectively a revert of commit 13dd4e0462 ("fsdax: unshare:
zero destination if srcmap is HOLE or UNWRITTEN")

Cc: ruansy.fnst@fujitsu.com
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/172796813311.1131942.16033376284752798632.stgit@frogsfrogsfrogs
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Stable-dep-of: 50793801fc ("fsdax: dax_unshare_iter needs to copy entire blocks")
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

This commit is contained in:

Darrick J. Wong 2024-10-03 08:09:32 -07:00 • committed by Greg Kroah-Hartman

parent aa56ea3b7d

commit a01987cd90

1 changed files with 0 additions and 8 deletions

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