On 23/04/2025 01:38, Darrick J. Wong wrote:
+ /*
+ * Set atomic write unit max for mp. Ignore devices which cannot atomic
+ * a single block, as they would be uncommon and more difficult to
+ * support.
+ */
+ if (mp->m_ddev_targp->bt_bdev_awu_min <= mp->m_sb.sb_blocksize &&
+ mp->m_ddev_targp->bt_bdev_awu_max >= mp->m_sb.sb_blocksize)
+ mp->m_dd_awu_hw_max = mp->m_ddev_targp->bt_bdev_awu_max;
If we don't want to use the device's atomic write capabilities due to
fsblock alignment problems, why not just zero out bt_bdev_awu_min/max?
That would cut down on the number of "awu" variables around the
codebase.
Sure, I did consider this, but thought it a bit unpleasant to zero out
structure members like this.
Ideally we could have not set them in the first place, but need to know
the blocksize when xfs_alloc_buftarg() is called, but it is not yet set
for mp/sb. Is there any neat way to know the blocksize when
xfs_alloc_buftarg() is called?
/*
* Ignore hardware atomic writes if the device can't handle a single
* fsblock for us. Most devices set the min_awu to the LBA size, but
* the spec allows for a functionality gap.
*/
static void
You would call this around the same point in xfs_mountfs(), right?
xfs_buftarg_reconcile_awu(
struct xfs_buftarg *btp)
{
struct xfs_mount *mp = btp->bt_mount;
if (btp->bt_bdev_awu_min > mp->m_sb.sb_blocksize ||
btp->bt_bdev_awu_max < mp->m_sb.sb_blocksize) {
btp->bt_bdev_awu_min = 0;
btp->bt_bdev_awu_max = 0;
}
}
xfs_buftarg_reconcile_awu(mp->m_ddev_targp);
if (mp->m_rtdev_targp)
xfs_buftarg_reconcile_awu(mp->m_rtdev_targp);
Hrm?
Cheers,
John
