diff options
| -rw-r--r-- | fs/btrfs/space-info.c | 35 |
1 files changed, 34 insertions, 1 deletions
diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c index 295c25101e23..9ac94d3119e8 100644 --- a/fs/btrfs/space-info.c +++ b/fs/btrfs/space-info.c @@ -1972,17 +1972,35 @@ int btrfs_calc_reclaim_threshold(struct btrfs_space_info *space_info) return READ_ONCE(space_info->bg_reclaim_threshold); } +/* + * Under "urgent" reclaim, we will reclaim even fresh block groups that have + * recently seen successful allocations, as we are desperate to reclaim + * whatever we can to avoid ENOSPC in a transaction leading to a readonly fs. + */ +static bool is_reclaim_urgent(struct btrfs_space_info *space_info) +{ + struct btrfs_fs_info *fs_info = space_info->fs_info; + u64 unalloc = atomic64_read(&fs_info->free_chunk_space); + u64 data_chunk_size = calc_effective_data_chunk_size(fs_info); + + return unalloc < data_chunk_size; +} + static int do_reclaim_sweep(struct btrfs_fs_info *fs_info, struct btrfs_space_info *space_info, int raid) { struct btrfs_block_group *bg; int thresh_pct; + bool try_again = true; + bool urgent; spin_lock(&space_info->lock); + urgent = is_reclaim_urgent(space_info); thresh_pct = btrfs_calc_reclaim_threshold(space_info); spin_unlock(&space_info->lock); down_read(&space_info->groups_sem); +again: list_for_each_entry(bg, &space_info->block_groups[raid], list) { u64 thresh; bool reclaim = false; @@ -1990,14 +2008,29 @@ static int do_reclaim_sweep(struct btrfs_fs_info *fs_info, btrfs_get_block_group(bg); spin_lock(&bg->lock); thresh = mult_perc(bg->length, thresh_pct); - if (bg->used < thresh && bg->reclaim_mark) + if (bg->used < thresh && bg->reclaim_mark) { + try_again = false; reclaim = true; + } bg->reclaim_mark++; spin_unlock(&bg->lock); if (reclaim) btrfs_mark_bg_to_reclaim(bg); btrfs_put_block_group(bg); } + + /* + * In situations where we are very motivated to reclaim (low unalloc) + * use two passes to make the reclaim mark check best effort. + * + * If we have any staler groups, we don't touch the fresher ones, but if we + * really need a block group, do take a fresh one. + */ + if (try_again && urgent) { + try_again = false; + goto again; + } + up_read(&space_info->groups_sem); return 0; } |