From 69fe2d75dd91d0124ad2ab6e9fef07633bd730e0 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Thu, 19 Oct 2017 14:15:57 -0400 Subject: btrfs: make the delalloc block rsv per inode The way we handle delalloc metadata reservations has gotten progressively more complicated over the years. There is so much cruft and weirdness around keeping the reserved count and outstanding counters consistent and handling the error cases that it's impossible to understand. Fix this by making the delalloc block rsv per-inode. This way we can calculate the actual size of the outstanding metadata reservations every time we make a change, and then reserve the delta based on that amount. This greatly simplifies the code everywhere, and makes the error handling in btrfs_delalloc_reserve_metadata far less terrifying. Signed-off-by: Josef Bacik Signed-off-by: David Sterba --- fs/btrfs/delayed-inode.c | 46 +--------------------------------------------- 1 file changed, 1 insertion(+), 45 deletions(-) (limited to 'fs/btrfs/delayed-inode.c') diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c index 19e4ad2f3f2e..5d73f79ded8b 100644 --- a/fs/btrfs/delayed-inode.c +++ b/fs/btrfs/delayed-inode.c @@ -581,36 +581,12 @@ static int btrfs_delayed_inode_reserve_metadata( struct btrfs_block_rsv *dst_rsv; u64 num_bytes; int ret; - bool release = false; src_rsv = trans->block_rsv; dst_rsv = &fs_info->delayed_block_rsv; num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1); - /* - * If our block_rsv is the delalloc block reserve then check and see if - * we have our extra reservation for updating the inode. If not fall - * through and try to reserve space quickly. - * - * We used to try and steal from the delalloc block rsv or the global - * reserve, but we'd steal a full reservation, which isn't kind. We are - * here through delalloc which means we've likely just cowed down close - * to the leaf that contains the inode, so we would steal less just - * doing the fallback inode update, so if we do end up having to steal - * from the global block rsv we hopefully only steal one or two blocks - * worth which is less likely to hurt us. - */ - if (src_rsv && src_rsv->type == BTRFS_BLOCK_RSV_DELALLOC) { - spin_lock(&inode->lock); - if (test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED, - &inode->runtime_flags)) - release = true; - else - src_rsv = NULL; - spin_unlock(&inode->lock); - } - /* * btrfs_dirty_inode will update the inode under btrfs_join_transaction * which doesn't reserve space for speed. This is a problem since we @@ -618,7 +594,7 @@ static int btrfs_delayed_inode_reserve_metadata( * space. * * Now if src_rsv == delalloc_block_rsv we'll let it just steal since - * we're accounted for. + * we always reserve enough to update the inode item. */ if (!src_rsv || (!trans->bytes_reserved && src_rsv->type != BTRFS_BLOCK_RSV_DELALLOC)) { @@ -643,32 +619,12 @@ static int btrfs_delayed_inode_reserve_metadata( } ret = btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, 1); - - /* - * Migrate only takes a reservation, it doesn't touch the size of the - * block_rsv. This is to simplify people who don't normally have things - * migrated from their block rsv. If they go to release their - * reservation, that will decrease the size as well, so if migrate - * reduced size we'd end up with a negative size. But for the - * delalloc_meta_reserved stuff we will only know to drop 1 reservation, - * but we could in fact do this reserve/migrate dance several times - * between the time we did the original reservation and we'd clean it - * up. So to take care of this, release the space for the meta - * reservation here. I think it may be time for a documentation page on - * how block rsvs. work. - */ if (!ret) { trace_btrfs_space_reservation(fs_info, "delayed_inode", btrfs_ino(inode), num_bytes, 1); node->bytes_reserved = num_bytes; } - if (release) { - trace_btrfs_space_reservation(fs_info, "delalloc", - btrfs_ino(inode), num_bytes, 0); - btrfs_block_rsv_release(fs_info, src_rsv, num_bytes); - } - return ret; } -- cgit v1.2.3