From: Ethan Lien ethanlien@synology.com
We use customized, nodesize batch value to update dirty_metadata_bytes. We should also use batch version of compare function or we will easily goto fast path and get false result from percpu_counter_compare().
Fixes: e2d845211eda ("Btrfs: use percpu counter for dirty metadata count") CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Ethan Lien ethanlien@synology.com Reviewed-by: Nikolay Borisov nborisov@suse.com Signed-off-by: David Sterba dsterba@suse.com [nb: Rebased on 4.4.y ] Signed-off-by: Nikolay Borisov nborisov@suse.com ---
Hello Greg,
Here is a working backport for 4.4.y of upstream commit: d814a49198eafa6163698bdd93961302f3a877a4
fs/btrfs/disk-io.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index d106b981d86f..ae6e3a30e61e 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -1011,8 +1011,9 @@ static int btree_writepages(struct address_space *mapping,
fs_info = BTRFS_I(mapping->host)->root->fs_info; /* this is a bit racy, but that's ok */ - ret = percpu_counter_compare(&fs_info->dirty_metadata_bytes, - BTRFS_DIRTY_METADATA_THRESH); + ret = __percpu_counter_compare(&fs_info->dirty_metadata_bytes, + BTRFS_DIRTY_METADATA_THRESH, + fs_info->dirty_metadata_batch); if (ret < 0) return 0; } @@ -3987,8 +3988,9 @@ static void __btrfs_btree_balance_dirty(struct btrfs_root *root, if (flush_delayed) btrfs_balance_delayed_items(root);
- ret = percpu_counter_compare(&root->fs_info->dirty_metadata_bytes, - BTRFS_DIRTY_METADATA_THRESH); + ret = __percpu_counter_compare(&root->fs_info->dirty_metadata_bytes, + BTRFS_DIRTY_METADATA_THRESH, + root->fs_info->dirty_metadata_batch); if (ret > 0) { balance_dirty_pages_ratelimited( root->fs_info->btree_inode->i_mapping);