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

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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>
This commit is contained in:
Liu Bo
2012-02-16 18:34:37 +08:00
committed by David Sterba
parent 285190d99f
commit 0449314a9c
1 changed files with 10 additions and 5 deletions
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15
fs/btrfs/extent_io.c
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@@ -513,6 +513,15 @@ hit_next:
WARN_ON(state->end < start); WARN_ON(state->end < start);
last_end = state->end; 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 ---- | * | ---- desired range ---- |
* | state | or * | state | or
@@ -565,12 +574,8 @@ hit_next:
goto out; 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); set |= clear_state_bit(tree, state, &bits, wake);
next:
if (last_end == (u64)-1) if (last_end == (u64)-1)
goto out; goto out;
start = last_end + 1; start = last_end + 1;