[PATCH 01/11] btrfs: Perform pinned cleanup directly in btrfs_destroy_delayed_refs

Nikolay Borisov
2020-01-20T14:09:33Z

Having btrfs_destroy_delayed_refs call btrfs_pin_extent is problematic
for making pinned extents tracking per-transaction since
btrfs_trans_handle cannot be passed to btrfs_pin_extent in this context.
Additionally delayed refs heads pinned in btrfs_destroy_delayed_refs
are going to be handled very closely, in btrfs_destroy_pinned_extent.

To enable btrfs_pin_extent to take btrfs_trans_handle simply open code
it in btrfs_destroy_delayed_refs and call btrfs_error_unpin_extent_range
on the range. This enables us to do less work in
btrfs_destroy_pinned_extent and leaves btrfs_pin_extent being called in
contexts which have a valid btrfs_trans_handle.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
---
fs/btrfs/disk-io.c | 26 +++++++++++++++++++++++---
1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 5ce2801f8388..9209c7b0997c 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -42,6 +42,7 @@
#include "ref-verify.h"
#include "block-group.h"
#include "discard.h"
+#include "space-info.h"

#define BTRFS_SUPER_FLAG_SUPP (BTRFS_HEADER_FLAG_WRITTEN |\
BTRFS_HEADER_FLAG_RELOC |\
@@ -4261,9 +4262,28 @@ static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
spin_unlock(&delayed_refs->lock);
mutex_unlock(&head->mutex);

- if (pin_bytes)
- btrfs_pin_extent(fs_info, head->bytenr,
- head->num_bytes, 1);
+ if (pin_bytes) {
+ struct btrfs_block_group *cache;
+ cache = btrfs_lookup_block_group(fs_info, head->bytenr);
+ BUG_ON(!cache);
+
+ spin_lock(&cache->space_info->lock);
+ spin_lock(&cache->lock);
+ cache->pinned += head->num_bytes;
+ btrfs_space_info_update_bytes_pinned(fs_info,
+ cache->space_info, head->num_bytes);
+ cache->reserved -= head->num_bytes;
+ cache->space_info->bytes_reserved -= head->num_bytes;
+ spin_unlock(&cache->lock);
+ spin_unlock(&cache->space_info->lock);
+ percpu_counter_add_batch(&cache->space_info->total_bytes_pinned,
+ head->num_bytes, BTRFS_TOTAL_BYTES_PINNED_BATCH);
+
+ btrfs_put_block_group(cache);
+
+ btrfs_error_unpin_extent_range(fs_info, head->bytenr,
+ head->bytenr + head->num_bytes - 1);
+ }
btrfs_cleanup_ref_head_accounting(fs_info, delayed_refs, head);
btrfs_put_delayed_ref_head(head);
cond_resched();
--
2.17.1