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vhost/scsi: forbid removing targets that are still being added

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It is theoretically possible for an asynchronous
hotremove request to be finished before the hotplug
request that was started first. This is obviously
not expected and will most likely result in a resource
leak.

For SCSI target hotplug, we immediately update the
whole vhost device object and then asynchronously
ask each vhost session to poll the changes.
For hotremove, we see the device attached in the
whole vhost device object, so we immediately mark
it as "still being removed" and proceed aynchronously
asking the sessions to hotremove. When session
receives the hotremove event first, it will either
fail an assertion (when debug is on), or do nothing.
The subsequent hotplug event will attach the target
again - and that target won't be ever freed.

Change-Id: I784c979fb47127a4238038ad9fb5ed1cac3ced04
Signed-off-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/449391
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Pawel Wodkowski <pawelx.wodkowski@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
This commit is contained in:
Darek Stojaczyk 2019-03-27 16:26:22 +01:00 committed by Jim Harris
parent 346b59bd40
commit 1188bdd70d
1 changed files with 13 additions and 4 deletions
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17
lib/vhost/vhost_scsi.c
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@ -71,6 +71,9 @@ enum spdk_scsi_dev_vhost_status {
/* Target ID is empty. */
VHOST_SCSI_DEV_EMPTY,
/* Target is still being added. */
VHOST_SCSI_DEV_ADDING,
/* Target ID occupied. */
VHOST_SCSI_DEV_PRESENT,
@ -933,7 +936,13 @@ spdk_vhost_scsi_session_add_tgt(struct spdk_vhost_dev *vdev,
int rc;
if (vsession == NULL) {
/* Nothing more to do */
struct spdk_vhost_scsi_dev *svdev = SPDK_CONTAINEROF(vdev,
struct spdk_vhost_scsi_dev, vdev);
vhost_sdev = &svdev->scsi_dev_state[scsi_tgt_num];
/* All sessions have added the target */
assert(vhost_sdev->status == VHOST_SCSI_DEV_ADDING);
vhost_sdev->status = VHOST_SCSI_DEV_PRESENT;
return 0;
}
@ -942,7 +951,7 @@ spdk_vhost_scsi_session_add_tgt(struct spdk_vhost_dev *vdev,
session_sdev = &svsession->scsi_dev_state[scsi_tgt_num];
session_sdev->dev = vhost_sdev->dev;
session_sdev->status = vhost_sdev->status;
session_sdev->status = VHOST_SCSI_DEV_PRESENT;
if (vsession->lcore == -1) {
/* All done. */
@ -1033,7 +1042,7 @@ spdk_vhost_scsi_dev_add_tgt(struct spdk_vhost_dev *vdev, int scsi_tgt_num,
lun_id_list[0] = 0;
bdev_names_list[0] = (char *)bdev_name;
state->status = VHOST_SCSI_DEV_PRESENT;
state->status = VHOST_SCSI_DEV_ADDING;
state->dev = spdk_scsi_dev_construct(target_name, bdev_names_list, lun_id_list, 1,
SPDK_SPC_PROTOCOL_IDENTIFIER_SAS,
spdk_vhost_scsi_lun_hotremove, svdev);
@ -1116,7 +1125,7 @@ spdk_vhost_scsi_dev_remove_tgt(struct spdk_vhost_dev *vdev, unsigned scsi_tgt_nu
}
scsi_dev_state = &svdev->scsi_dev_state[scsi_tgt_num];
if (scsi_dev_state->dev == NULL) {
if (scsi_dev_state->dev == NULL || scsi_dev_state->status == VHOST_SCSI_DEV_ADDING) {
SPDK_ERRLOG("Controller %s target %u is not occupied\n", vdev->name, scsi_tgt_num);
return -ENODEV;
}