From: Li Zefan Date: Thu, 8 Dec 2011 01:08:40 +0000 (-0500) Subject: Btrfs: check if the to-be-added device is writable X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=a5d16333612718569ffd26064270e535cb9c3928;p=GitHub%2Fmt8127%2Fandroid_kernel_alcatel_ttab.git Btrfs: check if the to-be-added device is writable If we call ioctl(BTRFS_IOC_ADD_DEV) directly, we'll succeed in adding a readonly device to a btrfs filesystem, and btrfs will write to that device, emitting kernel errors: [ 3109.833692] lost page write due to I/O error on loop2 [ 3109.833720] lost page write due to I/O error on loop2 ... Signed-off-by: Li Zefan Signed-off-by: Chris Mason --- diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index c37433d3cd82..0a8c8f8304b1 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1611,7 +1611,7 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path) if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding) return -EINVAL; - bdev = blkdev_get_by_path(device_path, FMODE_EXCL, + bdev = blkdev_get_by_path(device_path, FMODE_WRITE | FMODE_EXCL, root->fs_info->bdev_holder); if (IS_ERR(bdev)) return PTR_ERR(bdev);