On 6/20/24 14:53, John Garry wrote:
Add initial support for atomic writes. As is standard method, feed device properties via modules param, those being: - atomic_max_size_blks - atomic_alignment_blks - atomic_granularity_blks - atomic_max_size_with_boundary_blks - atomic_max_boundary_blks These just match sbc4r22 section 6.6.4 - Block limits VPD page. We just support ATOMIC WRITE (16). The major change in the driver is how we lock the device for RW accesses. Currently the driver uses a per-device lock for accessing device metadata and "media" data (calls to do_device_access()) atomically for the duration of the whole read/write command. This should not suit verifying atomic writes. Reason being that currently all reads/writes are atomic, so using atomic writes does not prove anything. Change device access model to basis that regular writes only atomic on a per-sector basis, while reads and atomic writes are fully atomic. As mentioned, since accessing metadata and device media is atomic, continue to have regular writes involving metadata - like discard or PI - as atomic. We can improve this later. Currently we only support model where overlapping going reads or writes wait for current access to complete before commencing an atomic write. This is described in 4.29.3.2 section of the SBC. However, we simplify, things and wait for all accesses to complete (when issuing an atomic write). Reviewed-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Signed-off-by: John Garry <john.g.garry@xxxxxxxxxx> --- drivers/scsi/scsi_debug.c | 588 +++++++++++++++++++++++++++++--------- 1 file changed, 454 insertions(+), 134 deletions(-)
Reviewed-by: Hannes Reinecke <hare@xxxxxxx> Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@xxxxxxx +49 911 74053 688 SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich
