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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Nathan Chancellor <nathan@kernel.org>,
        David Sterba <dsterba@suse.com>
Subject: [PATCH 5.17 009/219] btrfs: remove unused variable in btrfs_{start,write}_dirty_block_groups()
Date:   Mon, 18 Apr 2022 14:09:38 +0200
Message-Id: <20220418121203.738055874@linuxfoundation.org>
In-Reply-To: <20220418121203.462784814@linuxfoundation.org>
References: <20220418121203.462784814@linuxfoundation.org>
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From: Nathan Chancellor <nathan@kernel.org>

commit 6d4a6b515c39f1f8763093e0f828959b2fbc2f45 upstream.

Clang's version of -Wunused-but-set-variable recently gained support for
unary operations, which reveals two unused variables:

  fs/btrfs/block-group.c:2949:6: error: variable 'num_started' set but not used [-Werror,-Wunused-but-set-variable]
          int num_started = 0;
              ^
  fs/btrfs/block-group.c:3116:6: error: variable 'num_started' set but not used [-Werror,-Wunused-but-set-variable]
          int num_started = 0;
              ^
  2 errors generated.

These variables appear to be unused from their introduction, so just
remove them to silence the warnings.

Fixes: c9dc4c657850 ("Btrfs: two stage dirty block group writeout")
Fixes: 1bbc621ef284 ("Btrfs: allow block group cache writeout outside critical section in commit")
CC: stable@vger.kernel.org # 5.4+
Link: https://github.com/ClangBuiltLinux/linux/issues/1614
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/btrfs/block-group.c |    4 ----
 1 file changed, 4 deletions(-)

--- a/fs/btrfs/block-group.c
+++ b/fs/btrfs/block-group.c
@@ -2922,7 +2922,6 @@ int btrfs_start_dirty_block_groups(struc
 	struct btrfs_path *path = NULL;
 	LIST_HEAD(dirty);
 	struct list_head *io = &cur_trans->io_bgs;
-	int num_started = 0;
 	int loops = 0;
 
 	spin_lock(&cur_trans->dirty_bgs_lock);
@@ -2988,7 +2987,6 @@ again:
 			cache->io_ctl.inode = NULL;
 			ret = btrfs_write_out_cache(trans, cache, path);
 			if (ret == 0 && cache->io_ctl.inode) {
-				num_started++;
 				should_put = 0;
 
 				/*
@@ -3089,7 +3087,6 @@ int btrfs_write_dirty_block_groups(struc
 	int should_put;
 	struct btrfs_path *path;
 	struct list_head *io = &cur_trans->io_bgs;
-	int num_started = 0;
 
 	path = btrfs_alloc_path();
 	if (!path)
@@ -3147,7 +3144,6 @@ int btrfs_write_dirty_block_groups(struc
 			cache->io_ctl.inode = NULL;
 			ret = btrfs_write_out_cache(trans, cache, path);
 			if (ret == 0 && cache->io_ctl.inode) {
-				num_started++;
 				should_put = 0;
 				list_add_tail(&cache->io_list, io);
 			} else {