From c87f08ca44e83b2c8d28f63f9c33f3a270a04bbe Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Wed, 16 Feb 2011 13:57:04 -0500 Subject: Btrfs: allow balance to explicitly allocate chunks as it relocates Btrfs device shrinking and balancing ends up reallocating all the blocks in order to allow COW to move them to new destinations. It is somewhat awkward in terms of ENOSPC because most of the enospc code is built around the idea that some operation on a reference counted tree triggers allocations in the non-reference counted trees. This commit changes the balancing code to deal with enospc by trying to allocate a new chunk. If that allocation succeeds, we go ahead and retry whatever failed due to enospc. Signed-off-by: Chris Mason --- fs/btrfs/relocation.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'fs/btrfs/relocation.c') diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index 0825e4ed9447..31ade5802ae8 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -3654,6 +3654,7 @@ static noinline_for_stack int relocate_block_group(struct reloc_control *rc) u32 item_size; int ret; int err = 0; + int progress = 0; path = btrfs_alloc_path(); if (!path) @@ -3666,9 +3667,10 @@ static noinline_for_stack int relocate_block_group(struct reloc_control *rc) } while (1) { + progress++; trans = btrfs_start_transaction(rc->extent_root, 0); BUG_ON(IS_ERR(trans)); - +restart: if (update_backref_cache(trans, &rc->backref_cache)) { btrfs_end_transaction(trans, rc->extent_root); continue; @@ -3781,6 +3783,15 @@ static noinline_for_stack int relocate_block_group(struct reloc_control *rc) } } } + if (trans && progress && err == -ENOSPC) { + ret = btrfs_force_chunk_alloc(trans, rc->extent_root, + rc->block_group->flags); + if (ret == 0) { + err = 0; + progress = 0; + goto restart; + } + } btrfs_release_path(rc->extent_root, path); clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY, -- cgit v1.2.3