Re: [PATCH linux-2.6-block:master 05/10] blk: add FUA support to SCSI disk

Tejun Heo
2005-07-26T16:55:32Z

05_blk_scsi-add-fua-support.patch

Add FUA support to SCSI disk.

Signed-off-by: Tejun Heo <htejun@gmail.com>

sd.c | 29 ++++++++++++++++++++++++++---
1 files changed, 26 insertions(+), 3 deletions(-)

Index: blk-fixes/drivers/scsi/sd.c
===================================================================
--- blk-fixes.orig/drivers/scsi/sd.c 2005-07-27 00:44:51.000000000 +0900
+++ blk-fixes/drivers/scsi/sd.c 2005-07-27 00:44:51.000000000 +0900
@@ -103,6 +103,7 @@ struct scsi_disk {
u8 write_prot;
unsigned WCE : 1; /* state of disk WCE bit */
unsigned RCD : 1; /* state of disk RCD bit, unused */
+ unsigned DPOFUA : 1; /* state of disk DPOFUA bit */
};

static DEFINE_IDR(sd_index_idr);
@@ -343,6 +344,7 @@ static int sd_init_command(struct scsi_c

if (block > 0xffffffff) {
SCpnt->cmnd[0] += READ_16 - READ_6;
+ SCpnt->cmnd[1] |= blk_fua_rq(rq) ? 0x8 : 0;
SCpnt->cmnd[2] = sizeof(block) > 4 ? (unsigned char) (block >> 56) & 0xff : 0;
SCpnt->cmnd[3] = sizeof(block) > 4 ? (unsigned char) (block >> 48) & 0xff : 0;
SCpnt->cmnd[4] = sizeof(block) > 4 ? (unsigned char) (block >> 40) & 0xff : 0;
@@ -362,6 +364,7 @@ static int sd_init_command(struct scsi_c
this_count = 0xffff;

SCpnt->cmnd[0] += READ_10 - READ_6;
+ SCpnt->cmnd[1] |= blk_fua_rq(rq) ? 0x8 : 0;
SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;
SCpnt->cmnd[3] = (unsigned char) (block >> 16) & 0xff;
SCpnt->cmnd[4] = (unsigned char) (block >> 8) & 0xff;
@@ -370,6 +373,17 @@ static int sd_init_command(struct scsi_c
SCpnt->cmnd[7] = (unsigned char) (this_count >> 8) & 0xff;
SCpnt->cmnd[8] = (unsigned char) this_count & 0xff;
} else {
+ if (unlikely(blk_fua_rq(rq))) {
+ /*
+ * This happens only if this drive failed
+ * 10byte rw command with ILLEGAL_REQUEST
+ * during operation and thus turned off
+ * use_10_for_rw.
+ */
+ printk(KERN_ERR "sd: FUA write on READ/WRITE(6) drive\n");
+ return 0;
+ }
+
if (this_count > 0xff)
this_count = 0xff;

@@ -1399,10 +1413,18 @@ sd_read_cache_type(struct scsi_disk *sdk
sdkp->RCD = 0;
}

+ sdkp->DPOFUA = (data.device_specific & 0x10) != 0;
+ if (sdkp->DPOFUA && !sdkp->device->use_10_for_rw) {
+ printk(KERN_NOTICE "SCSI device %s: uses "
+ "READ/WRITE(6), disabling FUA\n", diskname);
+ sdkp->DPOFUA = 0;
+ }
+
ct = sdkp->RCD + 2*sdkp->WCE;

- printk(KERN_NOTICE "SCSI device %s: drive cache: %s\n",
- diskname, types[ct]);
+ printk(KERN_NOTICE "SCSI device %s: drive cache: %s%s\n",
+ diskname, types[ct],
+ sdkp->DPOFUA ? " w/ FUA" : "");

return;
}
@@ -1489,7 +1511,8 @@ static int sd_revalidate_disk(struct gen
* QUEUE_ORDERED_TAG_* even when ordered tag is supported.
*/
if (sdkp->WCE)
- ordered = QUEUE_ORDERED_DRAIN_FLUSH;
+ ordered = sdkp->DPOFUA
+ ? QUEUE_ORDERED_DRAIN_FUA : QUEUE_ORDERED_DRAIN_FLUSH;
else
ordered = QUEUE_ORDERED_DRAIN;