From b9d0b38928e21560550bd3c1a278d6e004d3bde6 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Tue, 29 Sep 2015 10:35:16 +0800 Subject: [PATCH] btrfs: Add handler for invalidate page For btrfs_invalidatepage() and its variant evict_inode_truncate_page(), there will be pages don't reach disk. In that case, their reserved space won't be release nor freed by finish_ordered_io() nor delayed_ref handler. So we must free their qgroup reserved space, or we will leaking reserved space again. So this will patch will call btrfs_qgroup_free_data() for invalidatepage() and its variant evict_inode_truncate_page(). And due to the nature of new btrfs_qgroup_reserve/free_data() reserved space will only be reserved or freed once, so for pages which are already flushed to disk, their reserved space will be released and freed by delayed_ref handler. Double free won't be a problem. Signed-off-by: Qu Wenruo Signed-off-by: Chris Mason --- fs/btrfs/inode.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index ef5d3694b944..6670792704e8 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -5132,6 +5132,18 @@ static void evict_inode_truncate_pages(struct inode *inode) spin_unlock(&io_tree->lock); lock_extent_bits(io_tree, start, end, 0, &cached_state); + + /* + * If still has DELALLOC flag, the extent didn't reach disk, + * and its reserved space won't be freed by delayed_ref. + * So we need to free its reserved space here. + * (Refer to comment in btrfs_invalidatepage, case 2) + * + * Note, end is the bytenr of last byte, so we need + 1 here. + */ + if (state->state & EXTENT_DELALLOC) + btrfs_qgroup_free_data(inode, start, end - start + 1); + clear_extent_bit(io_tree, start, end, EXTENT_LOCKED | EXTENT_DIRTY | EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | @@ -8646,6 +8658,18 @@ static void btrfs_invalidatepage(struct page *page, unsigned int offset, } } + /* + * Qgroup reserved space handler + * Page here will be either + * 1) Already written to disk + * In this case, its reserved space is released from data rsv map + * and will be freed by delayed_ref handler finally. + * So even we call qgroup_free_data(), it won't decrease reserved + * space. + * 2) Not written to disk + * This means the reserved space should be freed here. + */ + btrfs_qgroup_free_data(inode, page_start, PAGE_CACHE_SIZE); if (!inode_evicting) { clear_extent_bit(tree, page_start, page_end, EXTENT_LOCKED | EXTENT_DIRTY | -- 2.39.5