[PATCH 2/2] Btrfs: use fastpath in extent state ops as much as possible

[Liu Bo]

Fully utilize our extent state's new helper functions to use
fastpath as much as possible.

Signed-off-by: Liu Bo <liubo2...@cn.fujitsu.com>
---
 fs/btrfs/extent_io.c |   44 ++++++++++++++++++--------------------------
 1 files changed, 18 insertions(+), 26 deletions(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 198c2ba..f6e9191 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -570,10 +570,8 @@ hit_next:
                if (err)
                        goto out;
                if (state->end <= end) {
-                       clear_state_bit(tree, state, &bits, wake);
-                       if (last_end == (u64)-1)
-                               goto out;
-                       start = last_end + 1;
+                       state = clear_state_bit(tree, state, &bits, wake);
+                       goto next;
                }
                goto search_again;
        }
@@ -781,7 +779,6 @@ hit_next:
         * Just lock what we found and keep going
         */
        if (state->start == start && state->end <= end) {
-               struct rb_node *next_node;
                if (state->state & exclusive_bits) {
                        *failed_start = state->start;
                        err = -EEXIST;
@@ -789,20 +786,15 @@ hit_next:
                }
 
                set_state_bits(tree, state, &bits);
-
                cache_state(state, cached_state);
                merge_state(tree, state);
                if (last_end == (u64)-1)
                        goto out;
-
                start = last_end + 1;
-               next_node = rb_next(&state->rb_node);
-               if (next_node && start < end && prealloc && !need_resched()) {
-                       state = rb_entry(next_node, struct extent_state,
-                                        rb_node);
-                       if (state->start == start)
-                               goto hit_next;
-               }
+               state = next_state(state);
+               if (start < end && state && state->start == start &&
+                   !need_resched())
+                       goto hit_next;
                goto search_again;
        }
 
@@ -845,6 +837,10 @@ hit_next:
                        if (last_end == (u64)-1)
                                goto out;
                        start = last_end + 1;
+                       state = next_state(state);
+                       if (start < end && state && state->start == start &&
+                           !need_resched())
+                               goto hit_next;
                }
                goto search_again;
        }
@@ -994,21 +990,14 @@ hit_next:
         * Just lock what we found and keep going
         */
        if (state->start == start && state->end <= end) {
-               struct rb_node *next_node;
-
                set_state_bits(tree, state, &bits);
-               clear_state_bit(tree, state, &clear_bits, 0);
+               state = clear_state_bit(tree, state, &clear_bits, 0);
                if (last_end == (u64)-1)
                        goto out;
-
                start = last_end + 1;
-               next_node = rb_next(&state->rb_node);
-               if (next_node && start < end && prealloc && !need_resched()) {
-                       state = rb_entry(next_node, struct extent_state,
-                                        rb_node);
-                       if (state->start == start)
-                               goto hit_next;
-               }
+               if (start < end && state && state->start == start &&
+                   !need_resched())
+                       goto hit_next;
                goto search_again;
        }
 
@@ -1042,10 +1031,13 @@ hit_next:
                        goto out;
                if (state->end <= end) {
                        set_state_bits(tree, state, &bits);
-                       clear_state_bit(tree, state, &clear_bits, 0);
+                       state = clear_state_bit(tree, state, &clear_bits, 0);
                        if (last_end == (u64)-1)
                                goto out;
                        start = last_end + 1;
+                       if (start < end && state && state->start == start &&
+                           !need_resched())
+                               goto hit_next;
                }
                goto search_again;
        }
-- 
1.6.5.2

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