I have also added a utility iscsi-swp to libiscsi that can be used to
manage the SWP flag of an iSCSI LUN.
./bin/iscsi-swp iscsi://127.0.0.1/iqn.ronnie.test/1 --swp on
On Sat, Jul 6, 2013 at 11:13 PM, Ronnie Sahlberg
<ronniesahlberg@xxxxxxxxx> wrote:
> Fix a bug in sbc_mode_page_update. We only have a subpagecode in byte 1
> IFF the SPF bit in byte 0 is set.
>
> Add support for using modeselect for the CONTROLS page and set the
> mask to allow SWP to be changed.
>
> Add a SWP flag to the device attributes and update this as the CONTROLS/SWP
> flag is set by the initiator.
>
> Update SBC so that we treat writeprotect as either the current ->readonly flag
> that is used to se the hard property for the lun, or the ->swp flag
> that is set in software by the initiators.
> Thus like on a real disk, SWP can be used to turn a read-write LUN to become
> temporarily readonly, but SWP can NOT be used to turn a physically readonly
> medium to become read-write.
>
> Signed-off-by: Ronnie Sahlberg <ronniesahlberg@xxxxxxxxx>
> ---
> usr/sbc.c | 37 +++++++++++++++++++++++++++++++------
> usr/spc.c | 1 +
> usr/target.c | 2 ++
> usr/tgtd.h | 1 +
> 4 files changed, 35 insertions(+), 6 deletions(-)
>
> diff --git a/usr/sbc.c b/usr/sbc.c
> index 1f50191..c4f012c 100644
> --- a/usr/sbc.c
> +++ b/usr/sbc.c
> @@ -69,17 +69,21 @@ static off_t find_next_hole(struct scsi_lu *dev, off_t offset)
> static int sbc_mode_page_update(struct scsi_cmd *cmd, uint8_t *data, int *changed)
> {
> uint8_t pcode = data[0] & 0x3f;
> - uint8_t subpcode = data[1];
> + uint8_t subpcode = 0;
> struct mode_pg *pg;
> uint8_t old;
>
> + if (data[0] & 0x40)
> + subpcode = data[1];
> +
> pg = find_mode_page(cmd->dev, pcode, subpcode);
> if (pg == NULL)
> return 1;
>
> eprintf("%x %x\n", pg->mode_data[0], data[2]);
>
> - if (pcode == 0x08) {
> + switch (pcode) {
> + case 0x08: /* Cachning mode page */
> old = pg->mode_data[0];
> if (0x4 & data[2])
> pg->mode_data[0] |= 0x4;
> @@ -90,6 +94,19 @@ static int sbc_mode_page_update(struct scsi_cmd *cmd, uint8_t *data, int *change
> *changed = 1;
>
> return 0;
> + case 0x0a: /* Control mode page */
> + old = pg->mode_data[2];
> + if (0x8 & data[4])
> + pg->mode_data[2] |= 0x8;
> + else
> + pg->mode_data[2] &= ~0x8;
> +
> + if (old != pg->mode_data[2])
> + *changed = 1;
> +
> + cmd->dev->attrs.swp = (0x8 & data[4]) ? 1 : 0;
> +
> + return 0;
> }
>
> return 1;
> @@ -110,7 +127,8 @@ static int sbc_mode_sense(int host_no, struct scsi_cmd *cmd)
> * If this is a read-only lun, we must modify the data and set the
> * write protect bit
> */
> - if (cmd->dev->attrs.readonly && ret == SAM_STAT_GOOD) {
> + if ((cmd->dev->attrs.readonly || cmd->dev->attrs.swp)
> + && ret == SAM_STAT_GOOD) {
> uint8_t *data, mode6;
>
> mode6 = (cmd->scb[0] == 0x1a);
> @@ -141,7 +159,7 @@ static int sbc_format_unit(int host_no, struct scsi_cmd *cmd)
> goto sense;
> }
>
> - if (cmd->dev->attrs.readonly) {
> + if (cmd->dev->attrs.readonly || cmd->dev->attrs.swp) {
> key = DATA_PROTECT;
> asc = ASC_WRITE_PROTECT;
> goto sense;
> @@ -199,7 +217,7 @@ static int sbc_unmap(int host_no, struct scsi_cmd *cmd)
> goto sense;
> }
>
> - if (lu->attrs.readonly) {
> + if (lu->attrs.readonly || cmd->dev->attrs.swp) {
> key = DATA_PROTECT;
> asc = ASC_WRITE_PROTECT;
> goto sense;
> @@ -290,7 +308,7 @@ static int sbc_rw(int host_no, struct scsi_cmd *cmd)
> break;
> }
>
> - if (lu->attrs.readonly) {
> + if (lu->attrs.readonly || cmd->dev->attrs.swp) {
> switch (cmd->scb[0]) {
> case WRITE_6:
> case WRITE_10:
> @@ -736,6 +754,13 @@ static tgtadm_err sbc_lu_init(struct scsi_lu *lu)
>
> /* Control page */
> add_mode_page(lu, "0x0a:0:10:2:0x10:0:0:0:0:0:0:2:0");
> + {
> + uint8_t mask[10];
> + memset(mask, 0, sizeof(mask));
> + mask[2] = 0x08; /* allow changing SWP */
> +
> + set_mode_page_changeable_mask(lu, 0x0a, 0, mask);
> + }
>
> /* Control Extensions mode page: TCMOS:1 */
> add_mode_page(lu, "0x0a:1:0x1c:0x04:0x00:0x00");
> diff --git a/usr/spc.c b/usr/spc.c
> index 0cbba95..15077ca 100644
> --- a/usr/spc.c
> +++ b/usr/spc.c
> @@ -2028,6 +2028,7 @@ int spc_lu_init(struct scsi_lu *lu)
> lu->attrs.thinprovisioning = 0;
> lu->attrs.removable = 0;
> lu->attrs.readonly = 0;
> + lu->attrs.swp = 0;
> lu->attrs.sense_format = 0;
>
> snprintf(lu->attrs.vendor_id, sizeof(lu->attrs.vendor_id),
> diff --git a/usr/target.c b/usr/target.c
> index 9a8f2fd..fd087ad 100644
> --- a/usr/target.c
> +++ b/usr/target.c
> @@ -2023,6 +2023,7 @@ tgtadm_err tgt_target_show_all(struct concat_buf *b)
> _TAB3 "Removable media: %s\n"
> _TAB3 "Prevent removal: %s\n"
> _TAB3 "Readonly: %s\n"
> + _TAB3 "SWP: %s\n"
> _TAB3 "Thin-provisioning: %s\n"
> _TAB3 "Backing store type: %s\n"
> _TAB3 "Backing store path: %s\n"
> @@ -2037,6 +2038,7 @@ tgtadm_err tgt_target_show_all(struct concat_buf *b)
> lu->attrs.removable ? "Yes" : "No",
> lu_prevent_removal(lu) ? "Yes" : "No",
> lu->attrs.readonly ? "Yes" : "No",
> + lu->attrs.swp ? "Yes" : "No",
> lu->attrs.thinprovisioning ? "Yes" : "No",
> lu->bst ?
> (lu->bst->bs_name ? : "Unknown") :
> diff --git a/usr/tgtd.h b/usr/tgtd.h
> index f3d9674..484e6e9 100644
> --- a/usr/tgtd.h
> +++ b/usr/tgtd.h
> @@ -74,6 +74,7 @@ struct lu_phy_attr {
> char qualifier; /* Peripheral Qualifier */
> char removable; /* Removable media */
> char readonly; /* Read-Only media */
> + char swp; /* Software Write Protect */
> char thinprovisioning; /* Use thin-provisioning for this LUN */
> char online; /* Logical Unit online */
> char sense_format; /* Descrptor format sense data supported */
> --
> 1.7.3.1
>
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