From: Filipe Manana <fdmanana@suse.com>
Date: Thu, 15 Jan 2026 21:17:35 +0000 (+0000)
Subject: btrfs: add and use helper to compute the available space for a block group
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c208aa0ef655bb9a3c379510802cadd0df512f0a;p=thirdparty%2Fkernel%2Flinux.git

btrfs: add and use helper to compute the available space for a block group

We have currently three places that compute how much available space a
block group has. Add a helper function for this and use it in those
places.

Reviewed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---

diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c
index a1119f06b6d10..9d64cc60a42b5 100644
--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -1376,8 +1376,7 @@ static int inc_block_group_ro(struct btrfs_block_group *cache, bool force)
 		goto out;
 	}
 
-	num_bytes = cache->length - cache->reserved - cache->pinned -
-		    cache->bytes_super - cache->zone_unusable - cache->used;
+	num_bytes = btrfs_block_group_available_space(cache);
 
 	/*
 	 * Data never overcommits, even in mixed mode, so do just the straight
@@ -3089,7 +3088,6 @@ unlock_out:
 void btrfs_dec_block_group_ro(struct btrfs_block_group *cache)
 {
 	struct btrfs_space_info *sinfo = cache->space_info;
-	u64 num_bytes;
 
 	BUG_ON(!cache->ro);
 
@@ -3105,10 +3103,7 @@ void btrfs_dec_block_group_ro(struct btrfs_block_group *cache)
 			btrfs_space_info_update_bytes_zone_unusable(sinfo, cache->zone_unusable);
 			sinfo->bytes_readonly -= cache->zone_unusable;
 		}
-		num_bytes = cache->length - cache->reserved -
-			    cache->pinned - cache->bytes_super -
-			    cache->zone_unusable - cache->used;
-		sinfo->bytes_readonly -= num_bytes;
+		sinfo->bytes_readonly -= btrfs_block_group_available_space(cache);
 		list_del_init(&cache->ro_list);
 	}
 	spin_unlock(&cache->lock);
diff --git a/fs/btrfs/block-group.h b/fs/btrfs/block-group.h
index 5f933455118c7..cd2d53d5b3157 100644
--- a/fs/btrfs/block-group.h
+++ b/fs/btrfs/block-group.h
@@ -295,6 +295,14 @@ static inline bool btrfs_is_block_group_data_only(const struct btrfs_block_group
 	       !(block_group->flags & BTRFS_BLOCK_GROUP_METADATA);
 }
 
+static inline u64 btrfs_block_group_available_space(const struct btrfs_block_group *bg)
+{
+	lockdep_assert_held(&bg->lock);
+
+	return (bg->length - bg->used - bg->pinned - bg->reserved -
+		bg->bytes_super - bg->zone_unusable);
+}
+
 #ifdef CONFIG_BTRFS_DEBUG
 int btrfs_should_fragment_free_space(const struct btrfs_block_group *block_group);
 #endif
diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c
index 857e4fd2c77e0..1d76242f5e0df 100644
--- a/fs/btrfs/space-info.c
+++ b/fs/btrfs/space-info.c
@@ -656,8 +656,7 @@ again:
 		u64 avail;
 
 		spin_lock(&cache->lock);
-		avail = cache->length - cache->used - cache->pinned -
-			cache->reserved - cache->bytes_super - cache->zone_unusable;
+		avail = btrfs_block_group_available_space(cache);
 		btrfs_info(fs_info,
 "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %llu delalloc %llu super %llu zone_unusable (%llu bytes available) %s",
 			   cache->start, cache->length, cache->used, cache->pinned,