From: Miao Xie Date: Mon, 7 Jun 2010 03:38:51 +0000 (+0000) Subject: Btrfs: fix loop device on top of btrfs X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=4a001071d3549f596c7c3736c5dda8a3a4aba9ed;p=openwrt%2Fstaging%2Fblogic.git Btrfs: fix loop device on top of btrfs We cannot use the loop device which has been connected to a file in the btrf The reproduce steps is following: # dd if=/dev/zero of=vdev0 bs=1M count=1024 # losetup /dev/loop0 vdev0 # mkfs.btrfs /dev/loop0 ... failed to zero device start -5 The reason is that the btrfs don't implement either ->write_begin or ->write the VFS API, so we fix it by setting ->write to do_sync_write(). Signed-off-by: Miao Xie Signed-off-by: Chris Mason --- diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 79437c5eeb1e..abcb91867b56 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -1197,6 +1197,7 @@ static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma) const struct file_operations btrfs_file_operations = { .llseek = generic_file_llseek, .read = do_sync_read, + .write = do_sync_write, .aio_read = generic_file_aio_read, .splice_read = generic_file_splice_read, .aio_write = btrfs_file_aio_write,