From: Kai Mäkisara Kai.Makisara@kolumbus.fi
[ Upstream commit 0b120edb37dc9dd8ca82893d386922eb6b16f860 ]
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 Link: https://bugzilla.kernel.org/show_bug.cgi?id=219419#c14 Link: https://lore.kernel.org/r/20241106095723.63254-3-Kai.Makisara@kolumbus.fi Reviewed-by: John Meneghini jmeneghi@redhat.com Tested-by: John Meneghini jmeneghi@redhat.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/st.c | 29 +++++++++++++++++++++-------- 1 file changed, 21 insertions(+), 8 deletions(-)
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c index 4e0737c25fbdf..49e149d28954a 100644 --- a/drivers/scsi/st.c +++ b/drivers/scsi/st.c @@ -3505,6 +3505,7 @@ 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)) {