From eb14ab8ed24a0405fd056068b28c33a1cd846024 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Thu, 10 Feb 2011 12:35:00 -0500 Subject: Btrfs: fix page->private races There is a race where btrfs_releasepage can drop the page->private contents just as alloc_extent_buffer is setting up pages for metadata. Because of how the Btrfs page flags work, this results in us skipping the crc on the page during IO. This patch sovles the race by waiting until after the extent buffer is inserted into the radix tree before it sets page private. Signed-off-by: Chris Mason --- fs/btrfs/disk-io.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'fs/btrfs/disk-io.c') diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index b36eeef19194..3e1ea3e0477e 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -359,10 +359,14 @@ static int csum_dirty_buffer(struct btrfs_root *root, struct page *page) tree = &BTRFS_I(page->mapping->host)->io_tree; - if (page->private == EXTENT_PAGE_PRIVATE) + if (page->private == EXTENT_PAGE_PRIVATE) { + WARN_ON(1); goto out; - if (!page->private) + } + if (!page->private) { + WARN_ON(1); goto out; + } len = page->private >> 2; WARN_ON(len == 0); -- cgit v1.2.3