btrfs: convert pr_* to btrfs_* where possible

For many printks, we want to know which file system issued the message.

This patch converts most pr_* calls to use the btrfs_* versions instead.
In some cases, this means adding plumbing to allow call sites access to
an fs_info pointer.

fs/btrfs/check-integrity.c is left alone for another day.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index a5d81f3..8d93854 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -322,10 +322,11 @@
 		elem = list_first_entry(&fs_info->tree_mod_seq_list,
 					struct seq_list, list);
 		if (seq >= elem->seq) {
-			pr_debug("holding back delayed_ref %#x.%x, lowest is %#x.%x (%p)\n",
-				 (u32)(seq >> 32), (u32)seq,
-				 (u32)(elem->seq >> 32), (u32)elem->seq,
-				 delayed_refs);
+			btrfs_debug(fs_info,
+				"holding back delayed_ref %#x.%x, lowest is %#x.%x (%p)",
+				(u32)(seq >> 32), (u32)seq,
+				(u32)(elem->seq >> 32), (u32)elem->seq,
+				delayed_refs);
 			ret = 1;
 		}
 	}