xfs: provide helper for counting extents from if_bytes

commit 5d829300bee000980a09ac2ccb761cb25867b67c upstream.

The open-coded pattern:

ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t)

is all over the xfs code; provide a new helper
xfs_iext_count(ifp) to count the number of inline extents
in an inode fork.

[dchinner: pick up several missed conversions]

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
index a60d9e2..45e50ea 100644
--- a/fs/xfs/xfs_qm.c
+++ b/fs/xfs/xfs_qm.c
@@ -1135,7 +1135,7 @@
 			return error;
 	}
 	rtblks = 0;
-	nextents = ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t);
+	nextents = xfs_iext_count(ifp);
 	for (idx = 0; idx < nextents; idx++)
 		rtblks += xfs_bmbt_get_blockcount(xfs_iext_get_ext(ifp, idx));
 	*O_rtblks = (xfs_qcnt_t)rtblks;