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Commit b9d0b389 authored by Qu Wenruo's avatar Qu Wenruo Committed by Chris Mason
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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: default avatarQu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent 94ed938a

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 |