btrfs: Add handler for invalidate page (b9d0b389) · Commits · 戴 / test

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 <quwenruo@cn.fujitsu.com> Signed-off-by:

Chris Mason <clm@fb.com>

fs/btrfs/inode.c

+24 −0

Original line number	Diff line number	Diff line
		@@ -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 \|

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