From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C114E1448E0 for ; Sat, 4 Jul 2026 00:47:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783126022; cv=none; b=WpNk6kMAvGO+gey5ImUgkirM9s0baCzVVP/nvIGcPNvSV6UfhYoi4T3sAEf66Ihrrgf1WFouYvVtrg6ER2E5vYDosZl60brBBwV+TmHgeBGosg0ydmSQmgOkX4xfIKfR6h7C2or/qLOieo4HZ49JDUP0piS052emOtzC608s83Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783126022; c=relaxed/simple; bh=4KZoKYGYOWkkWgTTqzH3clCmQ99PLLGlNg12DWX5nII=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Jm+drg+hClx5lAKUhgn1SDDplCmT9SBBXcTRf1+VfodW85U5UvREzn1HibVkcPz/lggrNWteWekwTP1XupaAln7fLj67I2JjEfrLiaJln2aWcAWC4zQTO10pzSZTFEjLZih7CDANH+fO6MgA2zGE9jyF3OWlKFMdVanAKyfYogg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=getIqHu+; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="getIqHu+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B481E1F00A3D; Sat, 4 Jul 2026 00:47:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783126021; bh=UprPzbp72wmifsQWVOc7khgoi2hcEbq3aEOJ9X6Flfw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=getIqHu+M60yNy22Fr9wYY8TOUbeL1GItQkzbEInzpkHqQgvgrYWA8i3Nm/+AWOWd TeORpmzcesq4E9Bf1L1QylXarmy97BJZLYj4A//ym8ndMutDagpFIqL8YDm3onHGhE OtxKTRelNjm8ffmwfSyowWKOGRJQR+k3Cpq6A8EGDi4l/9WJgzonQbduk+b15/tYQn vdfcW3NXJD01AQ067EwTzT+7gB9p0baMqS+psNBc9joJjhOsOAXgUsvScKBRmgcsDG XH7SI++wS3xbHznakUjwrwI7A9J/PnUPDpGD+Re+GwMs861nyF+2W7rXb7D8gBUzIr MtAR0rFX/jMTg== From: Sasha Levin To: stable@vger.kernel.org Cc: Chao Yu , stable@kernel.org, Ruipeng Qi , Chao Yu , Jaegeuk Kim , Sasha Levin Subject: [PATCH 5.15.y 2/2] f2fs: fix potential deadlock in gc_merge path of f2fs_balance_fs() Date: Fri, 3 Jul 2026 20:46:57 -0400 Message-ID: <20260704004657.433173-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260704004657.433173-1-sashal@kernel.org> References: <2026070242-embassy-abdominal-7557@gregkh> <20260704004657.433173-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Chao Yu [ Upstream commit 8b4468ec023d0d1b4669dfb867588997cc03a06b ] When we mount device w/ gc_merge mount option, we may suffer below potential deadlock: Kworker GC trehad Truncator - f2fs_write_cache_pages - f2fs_write_single_data_page - f2fs_do_write_data_page - folio_start_writeback --- set writeback flag on folio - f2fs_outplace_write_data : cached folio in internal bio cache - f2fs_balance_fs - wake_up(gc_thread) : wake up gc thread to run foreground GC - finish_wait(fggc_wq) : wait on the waitqueue --- wait on GC thread to finish the work - truncate_inode_pages_range - __filemap_get_folio(, FGP_LOCK) --- lock folio - truncate_inode_partial_folio - folio_wait_writeback --- wait on writeback being cleared - do_garbage_collect - move_data_page - f2fs_get_lock_data_folio - lock on folio --- blocked on folio's lock In order to avoid such deadlock, let's call below functions to commit cached bios in GC_MERGE path of f2fs_balance_fs() as the same as we did in NOGC_MERGE path. - f2fs_submit_merged_write(sbi, DATA); - f2fs_submit_all_merged_ipu_writes(sbi); Cc: stable@kernel.org Fixes: 351df4b20115 ("f2fs: add segment operations") Cc: Ruipeng Qi Reported: Sandeep Dhavale Signed-off-by: Chao Yu Signed-off-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Sasha Levin --- fs/f2fs/segment.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 2e05e899097a91..31b3ff1fa9ba5e 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -515,6 +515,13 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need) * dir/node pages without enough free segments. */ if (has_not_enough_free_secs(sbi, 0, 0)) { + /* + * Submit all cached OPU/IPU DATA bios before triggering + * foreground GC to avoid potential deadlocks. + */ + f2fs_submit_merged_write(sbi, DATA); + f2fs_submit_all_merged_ipu_writes(sbi); + if (test_opt(sbi, GC_MERGE) && sbi->gc_thread && sbi->gc_thread->f2fs_gc_task) { DEFINE_WAIT(wait); @@ -525,13 +532,6 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi, bool need) io_schedule(); finish_wait(&sbi->gc_thread->fggc_wq, &wait); } else { - /* - * Submit all cached OPU/IPU DATA bios before triggering - * foreground GC to avoid potential deadlocks. - */ - f2fs_submit_merged_write(sbi, DATA); - f2fs_submit_all_merged_ipu_writes(sbi); - down_write(&sbi->gc_lock); f2fs_gc(sbi, false, false, false, NULL_SEGNO); } -- 2.53.0