4.4-stable review patch. If anyone has any objections, please let me know.
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From: Ilya Dryomov idryomov@gmail.com
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
--- drivers/block/rbd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -2736,7 +2736,7 @@ static int rbd_img_obj_parent_read_full( * 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(str */ 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);