From: Dominique Martinet dominique.martinet@atmark-techno.com
btfs_file_read's truncate path has a comment noting '>0 means no extent' and bailing out immediately, but the buffer has not been written so probably needs zeroing out.
This is a theorical fix only and hasn't been tested on a file that actually runs this code path.
Signed-off-by: Dominique Martinet dominique.martinet@atmark-techno.com --- fs/btrfs/inode.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index efffec0f2e68..23c006c98c3b 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -756,9 +756,12 @@ int btrfs_file_read(struct btrfs_root *root, u64 ino, u64 file_offset, u64 len, btrfs_release_path(&path); ret = lookup_data_extent(root, &path, ino, cur, &next_offset); - /* <0 is error, >0 means no extent */ - if (ret) + /* <0 is error, >0 means no extent: zero end of buffer */ + if (ret) { + if (ret > 0) + memset(dest + cur, 0, end - cur); goto out; + } fi = btrfs_item_ptr(path.nodes[0], path.slots[0], struct btrfs_file_extent_item); ret = read_and_truncate_page(&path, fi, cur,