From b9d97cff256f0efafd00f76b8d10d668f64436e9 Mon Sep 17 00:00:00 2001
From: Josef Bacik <josef@toxicpanda.com>
Date: Thu, 20 Jul 2023 16:12:15 -0400
Subject: [PATCH] btrfs: move comments to btrfs_loop_type definition
Some of these loop types aren't described, and they should be with the
definitions to make it easier to tell what each of them do.
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/extent-tree.c | 37 ++++++++++++++++++++++++++++---------
1 file changed, 28 insertions(+), 9 deletions(-)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index d674e421ea75d..6dfe086523f98 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3329,11 +3329,38 @@ int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_ref *ref)
}
enum btrfs_loop_type {
+ /*
+ * Start caching block groups but do not wait for progress or for them
+ * to be done.
+ */
LOOP_CACHING_NOWAIT,
+
+ /*
+ * Wait for the block group free_space >= the space we're waiting for if
+ * the block group isn't cached.
+ */
LOOP_CACHING_WAIT,
+
+ /*
+ * Allow allocations to happen from block groups that do not yet have a
+ * size classification.
+ */
LOOP_UNSET_SIZE_CLASS,
+
+ /*
+ * Allocate a chunk and then retry the allocation.
+ */
LOOP_ALLOC_CHUNK,
+
+ /*
+ * Ignore the size class restrictions for this allocation.
+ */
LOOP_WRONG_SIZE_CLASS,
+
+ /*
+ * Ignore the empty size, only try to allocate the number of bytes
+ * needed for this allocation.
+ */
LOOP_NO_EMPTY_SIZE,
};
@@ -3927,15 +3954,7 @@ static int find_free_extent_update_loop(struct btrfs_fs_info *fs_info,
if (ffe_ctl->index < BTRFS_NR_RAID_TYPES)
return 1;
- /*
- * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
- * caching kthreads as we move along
- * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
- * LOOP_UNSET_SIZE_CLASS, allow unset size class
- * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
- * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
- * again
- */
+ /* See the comments for btrfs_loop_type for an explanation of the phases. */
if (ffe_ctl->loop < LOOP_NO_EMPTY_SIZE) {
ffe_ctl->index = 0;
/*
--
GitLab