4.9-stable review patch. If anyone has any objections, please let me know.
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From: Jeremy Cline jeremy@jcline.org
[ Upstream commit 20bd1d026aacc5399464f8328f305985c493cde3 ]
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 Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/scsi/sd.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -2401,6 +2401,7 @@ sd_read_write_protect_flag(struct scsi_d 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); @@ -2441,7 +2442,7 @@ sd_read_write_protect_flag(struct scsi_d "Test WP failed, assume Write Enabled\n"); } else { sdkp->write_prot = ((data.device_specific & 0x80) != 0); - set_disk_ro(sdkp->disk, sdkp->write_prot); + set_disk_ro(sdkp->disk, sdkp->write_prot || disk_ro); if (sdkp->first_scan || old_wp != sdkp->write_prot) { sd_printk(KERN_NOTICE, sdkp, "Write Protect is %s\n", sdkp->write_prot ? "on" : "off");