From: Josef Bacik <josef@toxicpanda.com>
Date: Tue, 22 Jun 2021 15:52:01 +0300
Subject: btrfs: rip out btrfs_space_info::total_bytes_pinned
Git-commit: 138a12d865749e28b39300b8a07337811253939b
Patch-mainline: v5.14-rc1
References: bsc#1202528

We used this in may_commit_transaction() in order to determine if we
needed to commit the transaction.  However we no longer have that logic
and thus have no use of this counter anymore, so delete it.

Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Acked-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/block-group.c |    3 ---
 fs/btrfs/delayed-ref.c |   26 --------------------------
 fs/btrfs/extent-tree.c |   15 ---------------
 fs/btrfs/space-info.c  |    8 --------
 fs/btrfs/space-info.h  |   30 ------------------------------
 fs/btrfs/sysfs.c       |   13 -------------
 6 files changed, 95 deletions(-)

--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -1357,7 +1357,6 @@ void btrfs_delete_unused_bgs(struct btrf
 		btrfs_space_info_update_bytes_pinned(fs_info, space_info,
 						     -block_group->pinned);
 		space_info->bytes_readonly += block_group->pinned;
-		__btrfs_mod_total_bytes_pinned(space_info, -block_group->pinned);
 		block_group->pinned = 0;
 
 		spin_unlock(&block_group->lock);
@@ -2712,8 +2711,6 @@ int btrfs_update_block_group(struct btrf
 			spin_unlock(&cache->lock);
 			spin_unlock(&cache->space_info->lock);
 
-			__btrfs_mod_total_bytes_pinned(cache->space_info,
-						       num_bytes);
 			set_extent_dirty(info->pinned_extents,
 					 bytenr, bytenr + num_bytes - 1,
 					 GFP_NOFS | __GFP_NOFAIL);
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -660,7 +660,6 @@ static noinline void update_existing_hea
 	struct btrfs_delayed_ref_root *delayed_refs =
 		&trans->transaction->delayed_refs;
 	struct btrfs_fs_info *fs_info = trans->fs_info;
-	u64 flags = btrfs_ref_head_to_space_flags(existing);
 	int old_ref_mod;
 
 	BUG_ON(existing->is_data != update->is_data);
@@ -730,26 +729,6 @@ static noinline void update_existing_hea
 		}
 	}
 
-	/*
-	 * This handles the following conditions:
-	 *
-	 * 1. We had a ref mod of 0 or more and went negative, indicating that
-	 *    we may be freeing space, so add our space to the
-	 *    total_bytes_pinned counter.
-	 * 2. We were negative and went to 0 or positive, so no longer can say
-	 *    that the space would be pinned, decrement our counter from the
-	 *    total_bytes_pinned counter.
-	 * 3. We are now at 0 and have ->must_insert_reserved set, which means
-	 *    this was a new allocation and then we dropped it, and thus must
-	 *    add our space to the total_bytes_pinned counter.
-	 */
-	if (existing->total_ref_mod < 0 && old_ref_mod >= 0)
-		btrfs_mod_total_bytes_pinned(fs_info, flags, existing->num_bytes);
-	else if (existing->total_ref_mod >= 0 && old_ref_mod < 0)
-		btrfs_mod_total_bytes_pinned(fs_info, flags, -existing->num_bytes);
-	else if (existing->total_ref_mod == 0 && existing->must_insert_reserved)
-		btrfs_mod_total_bytes_pinned(fs_info, flags, existing->num_bytes);
-
 	spin_unlock(&existing->lock);
 }
 
@@ -856,17 +835,12 @@ add_delayed_ref_head(struct btrfs_fs_inf
 		kmem_cache_free(btrfs_delayed_ref_head_cachep, head_ref);
 		head_ref = existing;
 	} else {
-		u64 flags = btrfs_ref_head_to_space_flags(head_ref);
-
 		if (head_ref->is_data && head_ref->ref_mod < 0) {
 			delayed_refs->pending_csums += head_ref->num_bytes;
 			trans->delayed_ref_updates +=
 				btrfs_csum_bytes_to_leaves(trans->fs_info,
 							   head_ref->num_bytes);
 		}
-		if (head_ref->ref_mod < 0)
-			btrfs_mod_total_bytes_pinned(trans->fs_info, flags,
-						     head_ref->num_bytes);
 		delayed_refs->num_heads++;
 		delayed_refs->num_heads_ready++;
 		atomic_inc(&delayed_refs->num_entries);
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1929,19 +1929,6 @@ void btrfs_cleanup_ref_head_accounting(s
 		nr_items += btrfs_csum_bytes_to_leaves(fs_info, head->num_bytes);
 	}
 
-	/*
-	 * We were dropping refs, or had a new ref and dropped it, and thus must
-	 * adjust down our total_bytes_pinned, the space may or may not have
-	 * been pinned and so is accounted for properly in the pinned space by
-	 * now.
-	 */
-	if (head->total_ref_mod < 0 ||
-	    (head->total_ref_mod == 0 && head->must_insert_reserved)) {
-		u64 flags = btrfs_ref_head_to_space_flags(head);
-
-		btrfs_mod_total_bytes_pinned(fs_info, flags, -head->num_bytes);
-	}
-
 	btrfs_delayed_refs_rsv_release(fs_info, nr_items);
 }
 
@@ -2797,7 +2784,6 @@ static int pin_down_extent(struct btrfs_
 
 	trace_btrfs_space_reservation(fs_info, "pinned",
 				      cache->space_info->flags, num_bytes, 1);
-	__btrfs_mod_total_bytes_pinned(cache->space_info, num_bytes);
 	set_extent_dirty(fs_info->pinned_extents, bytenr,
 			 bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
 	return 0;
@@ -3050,7 +3036,6 @@ static int unpin_extent_range(struct btr
 		cache->pinned -= len;
 		btrfs_space_info_update_bytes_pinned(fs_info, space_info, -len);
 		space_info->max_extent_size = 0;
-		__btrfs_mod_total_bytes_pinned(space_info, -len);
 		if (cache->ro) {
 			space_info->bytes_readonly += len;
 			readonly = true;
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -62,13 +62,6 @@ static int create_space_info(struct btrf
 	if (!space_info)
 		return -ENOMEM;
 
-	ret = percpu_counter_init(&space_info->total_bytes_pinned, 0,
-				 GFP_KERNEL);
-	if (ret) {
-		kfree(space_info);
-		return ret;
-	}
-
 	for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
 		INIT_LIST_HEAD(&space_info->block_groups[i]);
 	init_rwsem(&space_info->groups_sem);
@@ -85,7 +78,6 @@ static int create_space_info(struct btrf
 				    info->space_info_kobj, "%s",
 				    alloc_name(space_info->flags));
 	if (ret) {
-		percpu_counter_destroy(&space_info->total_bytes_pinned);
 		kobject_put(&space_info->kobj);
 		return ret;
 	}
--- a/fs/btrfs/space-info.h
+++ b/fs/btrfs/space-info.h
@@ -41,18 +41,6 @@ struct btrfs_space_info {
 
 	u64 flags;
 
-	/*
-	 * bytes_pinned is kept in line with what is actually pinned, as in
-	 * we've called update_block_group and dropped the bytes_used counter
-	 * and increased the bytes_pinned counter.  However this means that
-	 * bytes_pinned does not reflect the bytes that will be pinned once the
-	 * delayed refs are flushed, so this counter is inc'ed every time we
-	 * call btrfs_free_extent so it is a realtime count of what will be
-	 * freed once the transaction is committed.  It will be zeroed every
-	 * time the transaction commits.
-	 */
-	struct percpu_counter total_bytes_pinned;
-
 	struct list_head list;
 	/* Protected by the spinlock 'lock'. */
 	struct list_head ro_bgs;
@@ -156,22 +144,4 @@ static inline void btrfs_space_info_free
 }
 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 */
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -315,15 +315,6 @@ static ssize_t btrfs_space_info_show_##f
 }									\
 BTRFS_ATTR(space_info, field, btrfs_space_info_show_##field)
 
-static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
-						       struct kobj_attribute *a,
-						       char *buf)
-{
-	struct btrfs_space_info *sinfo = to_space_info(kobj);
-	s64 val = percpu_counter_sum(&sinfo->total_bytes_pinned);
-	return snprintf(buf, PAGE_SIZE, "%lld\n", val);
-}
-
 SPACE_INFO_ATTR(flags);
 SPACE_INFO_ATTR(total_bytes);
 SPACE_INFO_ATTR(bytes_used);
@@ -333,8 +324,6 @@ SPACE_INFO_ATTR(bytes_may_use);
 SPACE_INFO_ATTR(bytes_readonly);
 SPACE_INFO_ATTR(disk_used);
 SPACE_INFO_ATTR(disk_total);
-BTRFS_ATTR(space_info, total_bytes_pinned,
-	   btrfs_space_info_show_total_bytes_pinned);
 
 static struct attribute *space_info_attrs[] = {
 	BTRFS_ATTR_PTR(space_info, flags),
@@ -346,14 +335,12 @@ static struct attribute *space_info_attr
 	BTRFS_ATTR_PTR(space_info, bytes_readonly),
 	BTRFS_ATTR_PTR(space_info, disk_used),
 	BTRFS_ATTR_PTR(space_info, disk_total),
-	BTRFS_ATTR_PTR(space_info, total_bytes_pinned),
 	NULL,
 };
 
 static void space_info_release(struct kobject *kobj)
 {
 	struct btrfs_space_info *sinfo = to_space_info(kobj);
-	percpu_counter_destroy(&sinfo->total_bytes_pinned);
 	kfree(sinfo);
 }