rbd: use GFP_NOIO for parent stat and data requests

commit 1e37f2f84680fa7f8394fd444b6928e334495ccc upstream.

rbd_img_obj_exists_submit() and rbd_img_obj_parent_read_full() are on
the writeback path for cloned images -- we attempt a stat on the parent
object to see if it exists and potentially read it in to call copyup.
GFP_NOIO should be used instead of GFP_KERNEL here.

Link: http://tracker.ceph.com/issues/22014
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: David Disseldorp <ddiss@suse.de>
[idryomov@gmail.com: backport to < 4.9: context]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index fbdddd6f94b8dcabfca98d0204e65b9c85485da5..ca3bcc81b623207f53b53e855284384a9e14187b 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2736,7 +2736,7 @@ static int rbd_img_obj_parent_read_full(struct rbd_obj_request *obj_request)
         * from the parent.
         */
        page_count = (u32)calc_pages_for(0, length);
-       pages = ceph_alloc_page_vector(page_count, GFP_KERNEL);
+       pages = ceph_alloc_page_vector(page_count, GFP_NOIO);
        if (IS_ERR(pages)) {
                result = PTR_ERR(pages);
                pages = NULL;
@@ -2863,7 +2863,7 @@ static int rbd_img_obj_exists_submit(struct rbd_obj_request *obj_request)
         */
        size = sizeof (__le64) + sizeof (__le32) + sizeof (__le32);
        page_count = (u32)calc_pages_for(0, size);
-       pages = ceph_alloc_page_vector(page_count, GFP_KERNEL);
+       pages = ceph_alloc_page_vector(page_count, GFP_NOIO);
        if (IS_ERR(pages))
                return PTR_ERR(pages);