btrfs: handle space_info::total_bytes_pinned inside the delayed ref itself

Currently we pass things around to figure out if we maybe freeing data
based on the state of the delayed refs head.  This makes the accounting
sort of confusing and hard to follow, as it's distinctly separate from
the delayed ref heads stuff, but also depends on it entirely.

Fix this by explicitly adjusting the space_info->total_bytes_pinned in
the delayed refs code.  We now have two places where we modify this
counter, once where we create the delayed and destroy the delayed refs,
and once when we pin and unpin the extents.  This means there is a
slight overlap between delayed refs and the pin/unpin mechanisms, but
this is simply used by the ENOSPC infrastructure to determine if we need
to commit the transaction, so there's no adverse affect from this, we
might simply commit thinking it will give us enough space when it might
not.

CC: stable@vger.kernel.org # 5.10
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/fs/btrfs/space-info.h b/fs/btrfs/space-info.h
index 5646393b928c..74706f604bce 100644
--- a/fs/btrfs/space-info.h
+++ b/fs/btrfs/space-info.h
@@ -152,4 +152,21 @@ static inline void btrfs_space_info_free_bytes_may_use(
 int btrfs_reserve_data_bytes(struct btrfs_fs_info *fs_info, u64 bytes,
 			     enum btrfs_reserve_flush_enum flush);
 
+static inline void __btrfs_mod_total_bytes_pinned(
+					struct btrfs_space_info *space_info,
+					s64 mod)
+{
+	percpu_counter_add_batch(&space_info->total_bytes_pinned, mod,
+				 BTRFS_TOTAL_BYTES_PINNED_BATCH);
+}
+
+static inline void btrfs_mod_total_bytes_pinned(struct btrfs_fs_info *fs_info,
+						u64 flags, s64 mod)
+{
+	struct btrfs_space_info *space_info = btrfs_find_space_info(fs_info, flags);
+
+	ASSERT(space_info);
+	__btrfs_mod_total_bytes_pinned(space_info, mod);
+}
+
 #endif /* BTRFS_SPACE_INFO_H */