Re: [PATCH v4 4/5] ublk: support device recovery without I/O queueing

[Ming Lei <ming.lei@redhat.com>]

On Mon, Oct 07, 2024 at 12:24:17PM -0600, Uday Shankar wrote:
> ublk currently supports the following behaviors on ublk server exit:
> 
> A: outstanding I/Os get errors, subsequently issued I/Os get errors
> B: outstanding I/Os get errors, subsequently issued I/Os queue
> C: outstanding I/Os get reissued, subsequently issued I/Os queue
> 
> and the following behaviors for recovery of preexisting block devices by
> a future incarnation of the ublk server:
> 
> 1: ublk devices stopped on ublk server exit (no recovery possible)
> 2: ublk devices are recoverable using start/end_recovery commands
> 
> The userspace interface allows selection of combinations of these
> behaviors using flags specified at device creation time, namely:
> 
> default behavior: A + 1
> UBLK_F_USER_RECOVERY: B + 2
> UBLK_F_USER_RECOVERY|UBLK_F_USER_RECOVERY_REISSUE: C + 2
> 
> The behavior A + 2 is currently unsupported. Add support for this
> behavior under the new flag combination
> UBLK_F_USER_RECOVERY|UBLK_F_USER_RECOVERY_FAIL_IO.
> 
> Signed-off-by: Uday Shankar <ushankar@purestorage.com>

Reviewed-by: Ming Lei <ming.lei@redhat.com>


Thanks,
Ming