Use GFP_NOIO in vdev_disk_io_flush()

To avoid a potential deadlock when using a zvol as a swap
device prevent vdev_disk_io_flush() from performing IO during
the bio_alloc().

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1508

diff --git a/module/zfs/vdev_disk.c b/module/zfs/vdev_disk.c
index 31d1a28bdc9bfff35392cbd35e9a69915bd2447c..2869716155f634fa41a02dd0a9851976fb0b0efb 100644 (file)
--- a/module/zfs/vdev_disk.c
+++ b/module/zfs/vdev_disk.c
@@ -632,7 +632,7 @@ vdev_disk_io_flush(struct block_device *bdev, zio_t *zio)
        if (!q)
                return ENXIO;
 
-       bio = bio_alloc(GFP_KERNEL, 0);
+       bio = bio_alloc(GFP_NOIO, 0);
        if (!bio)
                return ENOMEM;