From: Nathan Chancellor <nathan@xxxxxxxxxx> 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@xxxxxxxxxxxxxxx # 5.4+ Link: https://github.com/ClangBuiltLinux/linux/issues/1614 Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx> Signed-off-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/btrfs/block-group.c | 4 ---- 1 file changed, 4 deletions(-) --- a/fs/btrfs/block-group.c +++ b/fs/btrfs/block-group.c @@ -2882,7 +2882,6 @@ 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); @@ -2948,7 +2947,6 @@ 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; /* @@ -3049,7 +3047,6 @@ 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) @@ -3107,7 +3104,6 @@ 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 { Patches currently in stable-queue which might be from nathan@xxxxxxxxxx are queue-5.15/btrfs-remove-no-longer-used-counter-when-reading-data-page.patch queue-5.15/btrfs-remove-unused-parameter-nr_pages-in-add_ra_bio_pages.patch queue-5.15/btrfs-remove-unused-variable-in-btrfs_-start-write-_dirty_block_groups.patch