Hotremoving a bdev exposed as a vhost-scsi LUN which
has an allocated io_channel is broken now. By detaching
LUNs from their SCSI devices at the start of LUN
hotremoval, we can end up with the LUN's descriptor
completely leaked.
Upon hotremove, each LUN fires a hotremove_cb to the
upper layer (iscsi/vhost) and starts a poller to
periodically check if lun->io_channel has been closed
already. While iSCSI allocates and frees io_channels
for particular LUNs separately using
spdk_scsi_lun_allocate_io_channel(), vhost allocates
and frees io_channels for the entire SCSI device using
spdk_scsi_dev_free_io_channels(), as it knows there's
only one LUN per SCSI device.
Since LUNs are removed from SCSI devices at the start
of LUN hotremoval, the spdk_scsi_dev_free_io_channels()
is not able to close the io_channel of the child LUN.
That LUN is no longer referenced there, and the function
returns immediately without any error.
By reverting this patch, we practically defer removing
LUN from SCSI device until the bdev descriptor is closed,
that is, until that spdk_scsi_dev_free_io_channels()
and the subsequent spdk_scsi_dev_destruct() in vhost
is called.
Historically, spdk_scsi_lun_free_io_channel() was
introduced after vhost-scsi already supported hotremove,
so before we can introduce a change like this one we
have to refactor vhost to use the new APIs first.
This reverts commit 497997bc6033399fc7ad33fa191472c11925d0ba.
Change-Id: I58a9988a22694f5b5b927173098ac8218270462e
Signed-off-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/455371
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Pawel Kaminski <pawelx.kaminski@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
7a1c568598