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file-posix: populate pwrite_zeroes_alignment

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Linux block devices require write zeroes alignment whereas files do not.

It may come as a surprise that block devices opened in buffered I/O mode
require the alignment for write zeroes requests although normal
read/write requests do not.

Therefore it is necessary to populate the pwrite_zeroes_alignment field.

Cc: qemu-stable@nongnu.org
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20251007141700.71891-2-stefanha@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Tested-by: Fiona Ebner <f.ebner@proxmox.com>
Reviewed-by: Fiona Ebner <f.ebner@proxmox.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2025-10-07 10:16:58 -04:00 • committed by Kevin Wolf
parent 8eeaa706ba
commit 98e788b91a
1 changed files with 16 additions and 0 deletions
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16
block/file-posix.c
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@ -1611,6 +1611,22 @@ static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
bs->bl.pdiscard_alignment = dalign;
}
#ifdef __linux__
/*
* Linux requires logical block size alignment for write zeroes even
* when normal reads/writes do not require alignment.
*/
if (!s->needs_alignment) {
ret = probe_logical_blocksize(s->fd,
&bs->bl.pwrite_zeroes_alignment);
if (ret < 0) {
error_setg_errno(errp, -ret,
"Failed to probe logical block size");
return;
}
}
#endif /* __linux__ */
}
raw_refresh_zoned_limits(bs, &st, errp);