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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: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
This commit is contained in:
Qu Wenruo 2015-09-29 10:35:16 +08:00 committed by Chris Mason
parent 94ed938aba
commit b9d0b38928
1 changed files with 24 additions and 0 deletions
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24
fs/btrfs/inode.c
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@ -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 |