[BLOCK] scsi: add FUA support to sd

Add FUA support for barriers to SCSI disk.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jens Axboe <axboe@suse.de>

1 files changed, 26 insertions, 3 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 2eefc9eb5da6..32d4d8d7b9f3 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -102,6 +102,7 @@ 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_cmnd * SCpnt)
         
         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_cmnd * SCpnt)
                         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_cmnd * SCpnt)
                 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;
+                }
+
                 SCpnt->cmnd[1] |= (unsigned char) ((block >> 16) & 0x1f);
                 SCpnt->cmnd[2] = (unsigned char) ((block >> 8) & 0xff);
                 SCpnt->cmnd[3] = (unsigned char) block & 0xff;
@@ -1395,10 +1409,18 @@ sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
                         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;
         }
@@ -1475,7 +1497,8 @@ static int sd_revalidate_disk(struct gendisk *disk)
          * 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;