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Commit 7bc9fdda authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

lguest: replace VIRTIO_F_BARRIER support with VIRTIO_F_FLUSH support 



VIRTIO_F_BARRIER is deprecated.  Replace it with VIRTIO_F_FLUSH
support.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
parent 02c42b7a

Documentation/lguest/lguest.c

+9 −20
Original line number Original line Diff line number Diff line
@@ -1638,15 +1638,6 @@ static void blk_request(struct virtqueue *vq) 
	 */

	 */

	off = out->sector * 512;

	off = out->sector * 512;





	/*

	 * The block device implements "barriers", where the Guest indicates

	 * that it wants all previous writes to occur before this write.  We

	 * don't have a way of asking our kernel to do a barrier, so we just

	 * synchronize all the data in the file.  Pretty poor, no?

	 */

	if (out->type & VIRTIO_BLK_T_BARRIER)

		fdatasync(vblk->fd);



	/*

	/*

	 * In general the virtio block driver is allowed to try SCSI commands.

	 * In general the virtio block driver is allowed to try SCSI commands.

	 * It'd be nice if we supported eject, for example, but we don't.

	 * It'd be nice if we supported eject, for example, but we don't.
@@ -1679,6 +1670,13 @@ static void blk_request(struct virtqueue *vq) 
			/* Die, bad Guest, die. */

			/* Die, bad Guest, die. */

			errx(1, "Write past end %llu+%u", off, ret);

			errx(1, "Write past end %llu+%u", off, ret);

		}

		}



		wlen = sizeof(*in);

		*in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR);

	} else if (out->type & VIRTIO_BLK_T_FLUSH) {

		/* Flush */

		ret = fdatasync(vblk->fd);

		verbose("FLUSH fdatasync: %i\n", ret);

		wlen = sizeof(*in);

		wlen = sizeof(*in);

		*in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR);

		*in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR);

	} else {

	} else {
@@ -1702,15 +1700,6 @@ static void blk_request(struct virtqueue *vq) 
		}

		}

	}

	}





	/*

	 * OK, so we noted that it was pretty poor to use an fdatasync as a

	 * barrier.  But Christoph Hellwig points out that we need a sync

	 * *afterwards* as well: "Barriers specify no reordering to the front

	 * or the back."  And Jens Axboe confirmed it, so here we are:

	 */

	if (out->type & VIRTIO_BLK_T_BARRIER)

		fdatasync(vblk->fd);



	/* Finished that request. */

	/* Finished that request. */

	add_used(vq, head, wlen);

	add_used(vq, head, wlen);

}

}
@@ -1735,8 +1724,8 @@ static void setup_block_file(const char *filename) 
	vblk->fd = open_or_die(filename, O_RDWR|O_LARGEFILE);

	vblk->fd = open_or_die(filename, O_RDWR|O_LARGEFILE);

	vblk->len = lseek64(vblk->fd, 0, SEEK_END);

	vblk->len = lseek64(vblk->fd, 0, SEEK_END);





	/* We support barriers. */

	/* We support FLUSH. */

	add_feature(dev, VIRTIO_BLK_F_BARRIER);

	add_feature(dev, VIRTIO_BLK_F_FLUSH);





	/* Tell Guest how many sectors this device has. */

	/* Tell Guest how many sectors this device has. */

	conf.capacity = cpu_to_le64(vblk->len / 512);

	conf.capacity = cpu_to_le64(vblk->len / 512);