@@ -22,6 +22,10 @@
* - Badari Pulavarty <pbadari@us.ibm.com>, Matthew Wilcox
* <willy@debian.org>, Kurt Garloff <garloff@suse.de>:
* Support 32k/1M disks.
+ * - Guido Trentalancia <guido@trentalancia.com> ignore Synchronize
+ * Cache command failures on hard-drives that do not support it
+ * and disable the Write Cache functionality on such devices as a
+ * precaution: this allows to keep using several obsolete drives.
*
* Logging policy (needs CONFIG_SCSI_LOGGING defined):
* - setting up transfer: SCSI_LOG_HLQUEUE levels 1 and 2
@@ -1633,6 +1637,20 @@ static int sd_sync_cache(struct scsi_dis
}
if (res) {
+ /*
+ * sshdr.sense_key == ILLEGAL_REQUEST means this drive
+ * doesn't support sync. There's not much to do and
+ * sync shouldn't fail.
+ */
+ if (sshdr->sense_key == ILLEGAL_REQUEST && sshdr->asc == 0x20) {
+ if (sdkp->WCE) {
+ sdkp->WCE = 0;
+ sd_printk(KERN_NOTICE, sdkp, "Drive does not support Synchronize Cache(10) command: disabling write cache.\n");
+ sd_set_flush_flag(sdkp);
+ }
+ return 0;
+ }
+
sd_print_result(sdkp, "Synchronize Cache(10) failed", res);
if (driver_byte(res) == DRIVER_SENSE)
@@ -2022,6 +2040,17 @@ static int sd_done(struct scsi_cmnd *SCp
req->rq_flags |= RQF_QUIET;
}
break;
+ case SYNCHRONIZE_CACHE:
+ if (sshdr.asc == 0x20) {
+ if (sdkp->WCE) {
+ sdkp->WCE = 0;
+ sd_printk(KERN_NOTICE, sdkp, "Drive does not support Synchronize Cache(10) command: disabling write cache.\n");
+ sd_set_flush_flag(sdkp);
+ }
+ SCpnt->result = 0;
+ good_bytes = scsi_bufflen(SCpnt);
+ }
+ break;
}
}
break;
Many obsolete hard drives do not support the Synchronize Cache SCSI command. Such command is generally issued during fsync() calls which at the moment therefore fail with the ILLEGAL_REQUEST sense key. Since this failure is currently treated as critical in the kernel SCSI disk driver, such obsolete hard drives cannot be used anymore: they cannot be formatted, mounted and/or checked using tools such as e2fsprogs. Because there is nothing which can be done if the drive does not support such command, such ILLEGAL_REQUEST should be treated as non-critical so that the underlying operation does not fail and the obsolete hard drive can be used normally. This patch disables the Write Cache feature as a precaution on hard drives which do not support the Synchronize Cache command and therefore the cache flushing functionality. Fixes bug: https://bugzilla.kernel.org/show_bug.cgi?id=203635 Signed-off-by: Guido Trentalancia <guido@trentalancia.com> --- drivers/scsi/sd.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+)