Btrfs: fix data space leak fix (fbf19087) · Commits · 戴 / test

There is a problem where page_mkwrite can be called on a dirtied page that already has a delalloc range associated with it. The fix is to clear any delalloc bits for the range we are dirtying so the space accounting gets handled properly. This is the same thing we do in the normal write case, so we are consistent across the board. With this patch we no longer leak reserved space. Signed-off-by:

Josef Bacik <jbacik@redhat.com> Signed-off-by:

Chris Mason <chris.mason@oracle.com>

fs/btrfs/inode.c

+11 −0

Original line number	Original line	Diff line number	Diff line
	@@ -4909,10 +4909,21 @@ again:
	goto again;		goto again;
	}		}

			/*
			* XXX - page_mkwrite gets called every time the page is dirtied, even
			* if it was already dirty, so for space accounting reasons we need to
			* clear any delalloc bits for the range we are fixing to save. There
			* is probably a better way to do this, but for now keep consistent with
			* prepare_pages in the normal write path.
			*/
			clear_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end,
			EXTENT_DIRTY \| EXTENT_DELALLOC, GFP_NOFS);

	ret = btrfs_set_extent_delalloc(inode, page_start, page_end);		ret = btrfs_set_extent_delalloc(inode, page_start, page_end);
	if (ret) {		if (ret) {
	unlock_extent(io_tree, page_start, page_end, GFP_NOFS);		unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
	ret = VM_FAULT_SIGBUS;		ret = VM_FAULT_SIGBUS;
			btrfs_free_reserved_data_space(root, inode, PAGE_CACHE_SIZE);
	goto out_unlock;		goto out_unlock;
	}		}
	ret = 0;		ret = 0;

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