[PATCH 4.16 34/72] ceph: fix rsize/wsize capping in ceph_direct_read_write()

[Greg Kroah-Hartman]

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ilya Dryomov <idryomov@xxxxxxxxx>

commit 3a15b38fd2efc1d648cb33186bf71e9138c93491 upstream.

rsize/wsize cap should be applied before ceph_osdc_new_request() is
called.  Otherwise, if the size is limited by the cap instead of the
stripe unit, ceph_osdc_new_request() would setup an extent op that is
bigger than what dio_get_pages_alloc() would pin and add to the page
vector, triggering asserts in the messenger.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 95cca2b44e54 ("ceph: limit osd write size")
Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
Reviewed-by: "Yan, Zheng" <zyan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/ceph/file.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -878,6 +878,11 @@ ceph_direct_read_write(struct kiocb *ioc
 		size_t start = 0;
 		ssize_t len;
 
+		if (write)
+			size = min_t(u64, size, fsc->mount_options->wsize);
+		else
+			size = min_t(u64, size, fsc->mount_options->rsize);
+
 		vino = ceph_vino(inode);
 		req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
 					    vino, pos, &size, 0,
@@ -893,11 +898,6 @@ ceph_direct_read_write(struct kiocb *ioc
 			break;
 		}
 
-		if (write)
-			size = min_t(u64, size, fsc->mount_options->wsize);
-		else
-			size = min_t(u64, size, fsc->mount_options->rsize);
-
 		len = size;
 		pages = dio_get_pages_alloc(iter, len, &start, &num_pages);
 		if (IS_ERR(pages)) {