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@xxxxxxxxxxxxxx>
---
v2:
Newly introduced
v3:
None
---
fs/btrfs/inode.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 2fe95f0..fee54b6 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5075,6 +5075,18 @@ 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 |
@@ -8592,6 +8604,18 @@ 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 |
--
2.6.1
--
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