From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f175.google.com ([209.85.192.175]:35102 "EHLO mail-pf0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750766AbdFFXpp (ORCPT ); Tue, 6 Jun 2017 19:45:45 -0400 Received: by mail-pf0-f175.google.com with SMTP id l89so28749806pfi.2 for ; Tue, 06 Jun 2017 16:45:44 -0700 (PDT) From: Omar Sandoval To: linux-btrfs@vger.kernel.org Cc: Josef Bacik , Liu Bo , kernel-team@fb.com Subject: [PATCH 4/7] Btrfs: always account pinned bytes when dropping a tree block ref Date: Tue, 6 Jun 2017 16:45:29 -0700 Message-Id: <6e19647f2f3fb86f042e43162d55ceefe7c85d3e.1496792333.git.osandov@fb.com> In-Reply-To: References: In-Reply-To: References: Sender: linux-btrfs-owner@vger.kernel.org List-ID: From: Omar Sandoval Currently, we only increment total_bytes_pinned in btrfs_free_tree_block() when dropping the last reference on the block. However, when the delayed ref is run later, we will decrement total_bytes_pinned regardless of whether it was the last reference or not. This causes the counter to underflow when the reference we dropped was not the last reference. Fix it by incrementing the counter unconditionally, which is what btrfs_free_extent() does. This makes total_bytes_pinned an overestimate when references to shared extents are dropped, but in the worst case this will just make us try to commit the transaction to try to free up space and find we didn't free enough. Signed-off-by: Omar Sandoval --- fs/btrfs/extent-tree.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 9cff937415cb..52f3a0486e64 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -7178,10 +7178,7 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans, BUG_ON(ret); /* -ENOMEM */ } - if (!last_ref) - return; - - if (btrfs_header_generation(buf) == trans->transid) { + if (last_ref && btrfs_header_generation(buf) == trans->transid) { struct btrfs_block_group_cache *cache; if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) { @@ -7212,11 +7209,13 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans, add_pinned_bytes(fs_info, buf->len, btrfs_header_level(buf), root->root_key.objectid); - /* - * Deleting the buffer, clear the corrupt flag since it doesn't matter - * anymore. - */ - clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags); + if (last_ref) { + /* + * Deleting the buffer, clear the corrupt flag since it doesn't + * matter anymore. + */ + clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags); + } } /* Can return -ENOMEM */ -- 2.13.0