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Wed, 14 Jan 2026 06:44:52 -0800 (PST) From: Jiasheng Jiang To: naohiro.aota@wdc.com Cc: boris@bur.io, clm@fb.com, dsterba@suse.com, jiashengjiangcool@gmail.com, linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3] btrfs: zoned: remove redundant space_info lock and variable in do_allocation_zoned Date: Wed, 14 Jan 2026 14:44:50 +0000 Message-Id: <20260114144450.48776-1-jiashengjiangcool@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit In do_allocation_zoned(), the code acquires space_info->lock before block_group->lock. However, the critical section does not access or modify any members of the space_info structure. Thus, the lock is redundant as it provides no necessary synchronization here. This change simplifies the locking logic and aligns the function with other zoned paths, such as __btrfs_add_free_space_zoned(), which only rely on block_group->lock. Since the 'space_info' local variable is no longer used after removing the lock calls, it is also removed. Removing this unnecessary lock reduces contention on the global space_info lock, improving concurrency in the zoned allocation path. Signed-off-by: Jiasheng Jiang --- Changelog: v2 -> v3: 1. Removed the description about the 'space_info->lock' in the comment block above do_allocation_zoned(). v1 -> v2: 1. Removed the description about avoiding deadlocks. --- fs/btrfs/extent-tree.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index e4cae34620d1..36b06ee47c1a 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -3824,9 +3824,8 @@ static int do_allocation_clustered(struct btrfs_block_group *block_group, * Lock nesting * ============ * - * space_info::lock - * block_group::lock - * fs_info::treelog_bg_lock + * block_group::lock + * fs_info::treelog_bg_lock */ /* @@ -3839,7 +3838,6 @@ static int do_allocation_zoned(struct btrfs_block_group *block_group, struct btrfs_block_group **bg_ret) { struct btrfs_fs_info *fs_info = block_group->fs_info; - struct btrfs_space_info *space_info = block_group->space_info; struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl; u64 start = block_group->start; u64 num_bytes = ffe_ctl->num_bytes; @@ -3900,7 +3898,6 @@ static int do_allocation_zoned(struct btrfs_block_group *block_group, */ } - spin_lock(&space_info->lock); spin_lock(&block_group->lock); spin_lock(&fs_info->treelog_bg_lock); spin_lock(&fs_info->relocation_bg_lock); @@ -4002,7 +3999,6 @@ static int do_allocation_zoned(struct btrfs_block_group *block_group, spin_unlock(&fs_info->relocation_bg_lock); spin_unlock(&fs_info->treelog_bg_lock); spin_unlock(&block_group->lock); - spin_unlock(&space_info->lock); return ret; } -- 2.25.1