Btrfs: skip states when they does not contain bits to clear

Clearing a range's bits is different with setting them, since we don't
need to touch them when states do not contain bits we want.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>

1 files changed, 10 insertions, 5 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 8d6f55fbd28e..fe14285b53f1 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -513,6 +513,15 @@ hit_next:
         WARN_ON(state->end < start);
         last_end = state->end;
 
+        if (state->end < end && !need_resched())
+                next_node = rb_next(&state->rb_node);
+        else
+                next_node = NULL;
+
+        /* the state doesn't have the wanted bits, go ahead */
+        if (!(state->state & bits))
+                goto next;
+
         /*
          *     | ---- desired range ---- |
          *  | state | or
@@ -565,12 +574,8 @@ hit_next:
                 goto out;
         }
 
-        if (state->end < end && prealloc && !need_resched())
-                next_node = rb_next(&state->rb_node);
-        else
-                next_node = NULL;
-
         set |= clear_state_bit(tree, state, &bits, wake);
+next:
         if (last_end == (u64)-1)
                 goto out;
         start = last_end + 1;