[PATCH 14/31] btrfs: use next_state instead of rb_next where we can

Josef Bacik
2022-09-02T20:17:20Z

We can simplify a lot of these functions where we have to cycle through
extent_state's by simply using next_state() instead of rb_next(). In
many spots this allows us to do things like

while (state) {
/* whatever */
state = next_state(state);
}

instead of

while (1) {
state = rb_entry(n, struct extent_state, rb_node);
n = rb_next(n);
if (!n)
break;
}

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/extent-io-tree.c | 57 +++++++++++++++++----------------------
1 file changed, 24 insertions(+), 33 deletions(-)

diff --git a/fs/btrfs/extent-io-tree.c b/fs/btrfs/extent-io-tree.c
index 4e3cbb4edbe2..32f86a524bdd 100644
--- a/fs/btrfs/extent-io-tree.c
+++ b/fs/btrfs/extent-io-tree.c
@@ -770,12 +770,10 @@ void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, u32 bits)
* our range starts
*/
node = tree_search(tree, start);
-process_node:
if (!node)
break;
-
state = rb_entry(node, struct extent_state, rb_node);
-
+process_node:
if (state->start > end)
goto out;

@@ -792,7 +790,7 @@ void wait_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, u32 bits)
break;

if (!cond_resched_lock(&tree->lock)) {
- node = rb_next(node);
+ state = next_state(state);
goto process_node;
}
}
@@ -1325,15 +1323,13 @@ find_first_extent_bit_state(struct extent_io_tree *tree, u64 start, u32 bits)
node = tree_search(tree, start);
if (!node)
goto out;
+ state = rb_entry(node, struct extent_state, rb_node);

- while (1) {
+ while (state) {
state = rb_entry(node, struct extent_state, rb_node);
if (state->end >= start && (state->state & bits))
return state;
-
- node = rb_next(node);
- if (!node)
- break;
+ state = next_state(state);
}
out:
return NULL;
@@ -1521,18 +1517,15 @@ void find_first_clear_extent_bit(struct extent_io_tree *tree, u64 start,
* Find the longest stretch from start until an entry which has the
* bits set
*/
- while (1) {
- state = rb_entry(node, struct extent_state, rb_node);
+ state = rb_entry(node, struct extent_state, rb_node);
+ while (state) {
if (state->end >= start && !(state->state & bits)) {
*end_ret = state->end;
} else {
*end_ret = state->start - 1;
break;
}
-
- node = rb_next(node);
- if (!node)
- break;
+ state = next_state(state);
}
out:
spin_unlock(&tree->lock);
@@ -1566,8 +1559,8 @@ bool btrfs_find_delalloc_range(struct extent_io_tree *tree, u64 *start,
goto out;
}

- while (1) {
- state = rb_entry(node, struct extent_state, rb_node);
+ state = rb_entry(node, struct extent_state, rb_node);
+ while (state) {
if (found && (state->start != cur_start ||
(state->state & EXTENT_BOUNDARY))) {
goto out;
@@ -1585,12 +1578,10 @@ bool btrfs_find_delalloc_range(struct extent_io_tree *tree, u64 *start,
found = true;
*end = state->end;
cur_start = state->end + 1;
- node = rb_next(node);
total_bytes += state->end - state->start + 1;
if (total_bytes >= max_bytes)
break;
- if (!node)
- break;
+ state = next_state(state);
}
out:
spin_unlock(&tree->lock);
@@ -1629,8 +1620,8 @@ u64 count_range_bits(struct extent_io_tree *tree,
if (!node)
goto out;

- while (1) {
- state = rb_entry(node, struct extent_state, rb_node);
+ state = rb_entry(node, struct extent_state, rb_node);
+ while (state) {
if (state->start > search_end)
break;
if (contig && found && state->start > last + 1)
@@ -1648,9 +1639,7 @@ u64 count_range_bits(struct extent_io_tree *tree,
} else if (contig && found) {
break;
}
- node = rb_next(node);
- if (!node)
- break;
+ state = next_state(state);
}
out:
spin_unlock(&tree->lock);
@@ -1676,9 +1665,11 @@ int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
node = &cached->rb_node;
else
node = tree_search(tree, start);
- while (node && start <= end) {
- state = rb_entry(node, struct extent_state, rb_node);
+ if (!node)
+ goto out;

+ state = rb_entry(node, struct extent_state, rb_node);
+ while (state && start <= end) {
if (filled && state->start > start) {
bitset = 0;
break;
@@ -1702,13 +1693,13 @@ int test_range_bit(struct extent_io_tree *tree, u64 start, u64 end,
start = state->end + 1;
if (start > end)
break;
- node = rb_next(node);
- if (!node) {
- if (filled)
- bitset = 0;
- break;
- }
+ state = next_state(state);
}
+
+ /* We ran out of states and were still inside of our range. */
+ if (filled && !state)
+ bitset = 0;
+out:
spin_unlock(&tree->lock);
return bitset;
}
--
2.26.3