| Message ID | 01000161e1e448a5-d54e05d2-58f2-4480-b05b-67185d4ffae7-000000@email.amazonses.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On Thu, Mar 1, 2018 at 4:08 PM, Jeremy Cline <jeremy@jcline.org> wrote: > If the read-only flag is true on a SCSI disk, re-reading the partition > table sets the flag back to false. > > To observe this bug, you can run: > > 1. blockdev --setro /dev/sda > 2. blockdev --rereadpt /dev/sda > 3. blockdev --getro /dev/sda > > This commit reads the disk's old state and combines it with the device > disk-reported state rather than unconditionally marking it as RW. > - sdkp->write_prot = ((data.device_specific & 0x80) != 0); > + sdkp->write_prot = ((data.device_specific & 0x80) != 0) || > + disk_ro; Perhaps sdkp->write_prot = (data.device_specific & 0x80) || disk_ro; will save a line.
Jeremy, Thanks for looking into this! > This commit reads the disk's old state and combines it with the device > disk-reported state rather than unconditionally marking it as RW. Applied to 4.16/scsi-fixes with a few minor tweaks. Thank you!
On Thu, Mar 01, 2018 at 02:08:10PM +0000, Jeremy Cline wrote: > If the read-only flag is true on a SCSI disk, re-reading the partition > table sets the flag back to false. > > To observe this bug, you can run: > > 1. blockdev --setro /dev/sda > 2. blockdev --rereadpt /dev/sda > 3. blockdev --getro /dev/sda hi Jeremy, Do you mind wiring up a testcase in blktest [1] for this? Given that you already have a rather trivial reproducer. [1] https://github.com/osandov/ Thanks, Johannes
On 03/02/2018 07:00 AM, Johannes Thumshirn wrote: > On Thu, Mar 01, 2018 at 02:08:10PM +0000, Jeremy Cline wrote: >> If the read-only flag is true on a SCSI disk, re-reading the partition >> table sets the flag back to false. >> >> To observe this bug, you can run: >> >> 1. blockdev --setro /dev/sda >> 2. blockdev --rereadpt /dev/sda >> 3. blockdev --getro /dev/sda > > hi Jeremy, > > Do you mind wiring up a testcase in blktest [1] for this? Given that > you already have a rather trivial reproducer. > > [1] https://github.com/osandov/ Hi Johannes, Sure, I'll take care of it. Regards, Jeremy
On Fri, Mar 02, 2018 at 02:11:02PM +0000, Jeremy Cline wrote:
> Sure, I'll take care of it.
Thanks a lot.
Johannes
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index bff21e636ddd..7a3a66a7890f 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -2595,6 +2595,7 @@ sd_read_write_protect_flag(struct scsi_disk *sdkp, unsigned char *buffer) int res; struct scsi_device *sdp = sdkp->device; struct scsi_mode_data data; + int disk_ro = get_disk_ro(sdkp->disk); int old_wp = sdkp->write_prot; set_disk_ro(sdkp->disk, 0); @@ -2634,7 +2635,8 @@ sd_read_write_protect_flag(struct scsi_disk *sdkp, unsigned char *buffer) sd_first_printk(KERN_WARNING, sdkp, "Test WP failed, assume Write Enabled\n"); } else { - sdkp->write_prot = ((data.device_specific & 0x80) != 0); + sdkp->write_prot = ((data.device_specific & 0x80) != 0) || + disk_ro; set_disk_ro(sdkp->disk, sdkp->write_prot); if (sdkp->first_scan || old_wp != sdkp->write_prot) { sd_printk(KERN_NOTICE, sdkp, "Write Protect is %s\n",
If the read-only flag is true on a SCSI disk, re-reading the partition table sets the flag back to false. To observe this bug, you can run: 1. blockdev --setro /dev/sda 2. blockdev --rereadpt /dev/sda 3. blockdev --getro /dev/sda This commit reads the disk's old state and combines it with the device disk-reported state rather than unconditionally marking it as RW. Reported-by: Li Ning <lining916740672@icloud.com> Signed-off-by: Jeremy Cline <jeremy@jcline.org> --- drivers/scsi/sd.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)