On Sunday 15 August 2010 20:08:33 realrichardsharpe@xxxxxxxxx wrote:
> From: Richard Sharpe <realrichardsharpe@xxxxxxxxx>
>
> If the target returns logical_unit_not_supported when we send REPORT LUNS
> it means that it supports REPORT LUNS but there really are no LUNs there.
> Delete LUN 0 in that case.
>
> Also, when parsing the LUNs reported, remove any LUNs that used to exist
> in the gaps, and remove LUNs beyond the end of those reported. They no
> longer exist.
>
> Also don't scan a target where the ID is too large or the channel is
> too large.
>
> Tested by adding four LUNs with scst_local and then deleting them in
> various combinations, including deleting from LUN 0, deleting from last
> LUN and deleting in the middle out.
What happens if you stack the device? Say you got multipath on top of this or
device-mapper? Does this work properly ? For multipath I would expect it to
work OK, and multipath device would queue the I/O until a LUN with the same
SCSI_ID would reappear.
>
> Signed-off-by: Richard Sharpe <realrichardsharpe@xxxxxxxxx>
> ---
> drivers/scsi/scsi_scan.c | 65
> +++++++++++++++++++++++++++++++++++++++++++-- 1 files changed, 62
> insertions(+), 3 deletions(-)
>
> diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
> index 1c027a9..d0f5d30 100644
> --- a/drivers/scsi/scsi_scan.c
> +++ b/drivers/scsi/scsi_scan.c
> @@ -1309,7 +1309,7 @@ static int scsi_report_lun_scan(struct scsi_target
> *starget, int bflags, char devname[64];
> unsigned char scsi_cmd[MAX_COMMAND_SIZE];
> unsigned int length;
> - unsigned int lun;
> + unsigned int lun, old_lun = 0;
> unsigned int num_luns;
> unsigned int retries;
> int result;
> @@ -1410,6 +1410,22 @@ static int scsi_report_lun_scan(struct scsi_target
> *starget, int bflags, if (result == 0)
> break;
> else if (scsi_sense_valid(&sshdr)) {
> + /*
> + * This is awful. We should use a named constant!
> + * If the target returns logical_unit_not_supported
> + * then there really are zero LUNs there, so delete
> + * LUN 0 if it exists.
> + */
> + if (sshdr.asc == 0x25) {
> + struct scsi_device *sdev = NULL;
> + sdev = scsi_device_lookup_by_target(starget, 0);
> + if (sdev) {
> + scsi_device_put(sdev);
> + __scsi_remove_device(sdev);
> + SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
> + "Removing LUN 0\n"));
> + }
> + }
> if (sshdr.sense_key != UNIT_ATTENTION)
> break;
> }
> @@ -1473,6 +1489,27 @@ static int scsi_report_lun_scan(struct scsi_target
> *starget, int bflags, } else {
> int res;
>
> + /*
> + * First, check for and remove any missing LUNs, as
> + * they have been removed on the target.
> + */
> + if (lun > old_lun + 1) {
> + unsigned int i;
> + for (i = old_lun + 1; i < lun; i++) {
> + struct scsi_device *sdev;
> + sdev = scsi_device_lookup_by_target(
> + starget, i);
> + if (sdev) {
> + scsi_device_put(sdev);
> + __scsi_remove_device(sdev);
> + SCSI_LOG_SCAN_BUS(3,
> + printk(KERN_INFO
> + "Removing LUN %d\n",
> + i));
> + }
> + }
> + }
> +
> res = scsi_probe_and_add_lun(starget,
> lun, NULL, NULL, rescan, NULL);
> if (res == SCSI_SCAN_NO_RESPONSE) {
> @@ -1485,6 +1522,26 @@ static int scsi_report_lun_scan(struct scsi_target
> *starget, int bflags, " aborted\n", lun);
> break;
> }
> +
> + old_lun = lun;
> + }
> + }
> +
> + /*
> + * Remove any device that no longer exist. Does not work for LUN 0.
> + * See above.
> + */
> + if (lun < shost->max_lun) {
> + int i = 0;
> + for (i = lun + 1; i < shost->max_lun; i++) {
> + struct scsi_device *sdev;
> + sdev = scsi_device_lookup_by_target(starget, i);
> + if (sdev) {
> + scsi_device_put(sdev);
> + __scsi_remove_device(sdev);
> + SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
> + "Removed LUN %d\n", i));
> + }
> }
> }
>
> @@ -1565,9 +1622,11 @@ static void __scsi_scan_target(struct device
> *parent, unsigned int channel, int res;
> struct scsi_target *starget;
>
> - if (shost->this_id == id)
> + if (shost->this_id == id ||
> + id > shost->max_id ||
> + channel > shost->max_channel)
> /*
> - * Don't scan the host adapter
> + * Don't scan the host adapter or dis-allowed ones.
> */
> return;
--
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