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authorChris Mason <chris.mason@oracle.com>2011-02-10 12:35:00 -0500
committerChris Mason <chris.mason@oracle.com>2011-02-14 13:03:52 -0500
commiteb14ab8ed24a0405fd056068b28c33a1cd846024 (patch)
tree1451cad453a3ff66bc5369dc83daf7e3a50c4897 /fs/btrfs/disk-io.c
parent3a90983dbdcb2f4f48c0d771d8e5b4d88f27fae6 (diff)
downloadlinux-eb14ab8ed24a0405fd056068b28c33a1cd846024.tar.bz2
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 <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/disk-io.c')
-rw-r--r--fs/btrfs/disk-io.c8
1 files changed, 6 insertions, 2 deletions
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);