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lguest: replace VIRTIO_F_BARRIER support with VIRTIO_F_FLUSH support

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VIRTIO_F_BARRIER is deprecated.  Replace it with VIRTIO_F_FLUSH
support.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This commit is contained in:
Tejun Heo 2010-09-03 11:56:18 +02:00 committed by Jens Axboe
parent 02c42b7a68
commit 7bc9fddab0
1 changed files with 9 additions and 20 deletions
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29
Documentation/lguest/lguest.c
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@ -1638,15 +1638,6 @@ static void blk_request(struct virtqueue *vq)
*/
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.
* 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. */
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);
*in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR);
} 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. */
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->len = lseek64(vblk->fd, 0, SEEK_END);
/* We support barriers. */
add_feature(dev, VIRTIO_BLK_F_BARRIER);
/* We support FLUSH. */
add_feature(dev, VIRTIO_BLK_F_FLUSH);
/* Tell Guest how many sectors this device has. */
conf.capacity = cpu_to_le64(vblk->len / 512);