* [PATCH] scsi: sd: Keep disk read-only when re-reading partition
@ 2018-03-01 14:08 Jeremy Cline
2018-03-01 14:14 ` Andy Shevchenko
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Jeremy Cline @ 2018-03-01 14:08 UTC (permalink / raw)
To: James E . J . Bottomley, Martin K . Petersen
Cc: linux-scsi, linux-kernel, Jeremy Cline
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(-)
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",
--
2.16.2
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] scsi: sd: Keep disk read-only when re-reading partition
2018-03-01 14:08 [PATCH] scsi: sd: Keep disk read-only when re-reading partition Jeremy Cline
@ 2018-03-01 14:14 ` Andy Shevchenko
2018-03-02 1:53 ` Martin K. Petersen
2018-03-02 12:00 ` Johannes Thumshirn
2 siblings, 0 replies; 6+ messages in thread
From: Andy Shevchenko @ 2018-03-01 14:14 UTC (permalink / raw)
To: Jeremy Cline
Cc: James E . J . Bottomley, Martin K . Petersen, linux-scsi,
Linux Kernel Mailing List
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.
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] scsi: sd: Keep disk read-only when re-reading partition
2018-03-01 14:08 [PATCH] scsi: sd: Keep disk read-only when re-reading partition Jeremy Cline
2018-03-01 14:14 ` Andy Shevchenko
@ 2018-03-02 1:53 ` Martin K. Petersen
2018-03-02 12:00 ` Johannes Thumshirn
2 siblings, 0 replies; 6+ messages in thread
From: Martin K. Petersen @ 2018-03-02 1:53 UTC (permalink / raw)
To: Jeremy Cline
Cc: James E . J . Bottomley, Martin K . Petersen, linux-scsi, linux-kernel
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!
--
Martin K. Petersen Oracle Linux Engineering
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] scsi: sd: Keep disk read-only when re-reading partition
2018-03-01 14:08 [PATCH] scsi: sd: Keep disk read-only when re-reading partition Jeremy Cline
2018-03-01 14:14 ` Andy Shevchenko
2018-03-02 1:53 ` Martin K. Petersen
@ 2018-03-02 12:00 ` Johannes Thumshirn
2018-03-02 14:11 ` Jeremy Cline
2 siblings, 1 reply; 6+ messages in thread
From: Johannes Thumshirn @ 2018-03-02 12:00 UTC (permalink / raw)
To: Jeremy Cline
Cc: James E . J . Bottomley, Martin K . Petersen, linux-scsi, linux-kernel
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
--
Johannes Thumshirn Storage
jthumshirn@suse.de +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] scsi: sd: Keep disk read-only when re-reading partition
2018-03-02 12:00 ` Johannes Thumshirn
@ 2018-03-02 14:11 ` Jeremy Cline
2018-03-02 14:24 ` Johannes Thumshirn
0 siblings, 1 reply; 6+ messages in thread
From: Jeremy Cline @ 2018-03-02 14:11 UTC (permalink / raw)
To: Johannes Thumshirn
Cc: James E . J . Bottomley, Martin K . Petersen, linux-scsi, linux-kernel
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
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] scsi: sd: Keep disk read-only when re-reading partition
2018-03-02 14:11 ` Jeremy Cline
@ 2018-03-02 14:24 ` Johannes Thumshirn
0 siblings, 0 replies; 6+ messages in thread
From: Johannes Thumshirn @ 2018-03-02 14:24 UTC (permalink / raw)
To: Jeremy Cline
Cc: James E . J . Bottomley, Martin K . Petersen, linux-scsi, linux-kernel
On Fri, Mar 02, 2018 at 02:11:02PM +0000, Jeremy Cline wrote:
> Sure, I'll take care of it.
Thanks a lot.
Johannes
--
Johannes Thumshirn Storage
jthumshirn@suse.de +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
^ permalink raw reply [flat|nested] 6+ messages in thread
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2018-03-01 14:08 [PATCH] scsi: sd: Keep disk read-only when re-reading partition Jeremy Cline
2018-03-01 14:14 ` Andy Shevchenko
2018-03-02 1:53 ` Martin K. Petersen
2018-03-02 12:00 ` Johannes Thumshirn
2018-03-02 14:11 ` Jeremy Cline
2018-03-02 14:24 ` Johannes Thumshirn
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