diff mbox series

[v2,2/3] scsi: st: Add MTIOCGET and MTLOAD to ioctls allowed after device reset

Message ID 20241106095723.63254-3-Kai.Makisara@kolumbus.fi
State New
Headers show
Series scsi: st: Device reset patches | expand

Commit Message

Kai Mäkisara (Kolumbus) Nov. 6, 2024, 9:57 a.m. UTC 
Most drives rewind the tape when the device is reset. Reading
and writing are not allowed until something is done to make
the tape position match the user's expectation (e.g.,
rewind the tape). Add MTIOCGET and MTLOAD to operations allowed
after reset. MTIOCGET is modified to not touch the tape if
pos_unknown is non-zero. The tape location is known after MTLOAD.

Signed-off-by: Kai Mäkisara <Kai.Makisara@kolumbus.fi>
Reviewed-by: John Meneghini <jmeneghi@redhat.com>
Tested-by: John Meneghini <jmeneghi@redhat.com>
---
 drivers/scsi/st.c | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)
diff mbox series

Patch

diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 8d27e6caf027..c9038284bc89 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -3506,6 +3506,7 @@  static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
 	int i, cmd_nr, cmd_type, bt;
 	int retval = 0;
 	unsigned int blk;
+	bool cmd_mtiocget;
 	struct scsi_tape *STp = file->private_data;
 	struct st_modedef *STm;
 	struct st_partstat *STps;
@@ -3619,6 +3620,7 @@  static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
 			 */
 			if (mtc.mt_op != MTREW &&
 			    mtc.mt_op != MTOFFL &&
+			    mtc.mt_op != MTLOAD &&
 			    mtc.mt_op != MTRETEN &&
 			    mtc.mt_op != MTERASE &&
 			    mtc.mt_op != MTSEEK &&
@@ -3732,17 +3734,28 @@  static long st_ioctl(struct file *file, unsigned int cmd_in, unsigned long arg)
 		goto out;
 	}
 
+	cmd_mtiocget = cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET);
+
 	if ((i = flush_buffer(STp, 0)) < 0) {
-		retval = i;
-		goto out;
-	}
-	if (STp->can_partitions &&
-	    (i = switch_partition(STp)) < 0) {
-		retval = i;
-		goto out;
+		if (cmd_mtiocget && STp->pos_unknown) {
+			/* flush fails -> modify status accordingly */
+			reset_state(STp);
+			STp->pos_unknown = 1;
+		} else { /* return error */
+			retval = i;
+			goto out;
+		}
+	} else { /* flush_buffer succeeds */
+		if (STp->can_partitions) {
+			i = switch_partition(STp);
+			if (i < 0) {
+				retval = i;
+				goto out;
+			}
+		}
 	}
 
-	if (cmd_type == _IOC_TYPE(MTIOCGET) && cmd_nr == _IOC_NR(MTIOCGET)) {
+	if (cmd_mtiocget) {
 		struct mtget mt_status;
 
 		if (_IOC_SIZE(cmd_in) != sizeof(struct mtget)) {