diff options
Diffstat (limited to 'drivers/block/loop.c')
| -rw-r--r-- | drivers/block/loop.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 46cba261075f..b8ba7de08753 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -505,6 +505,17 @@ static void loop_assign_backing_file(struct loop_device *lo, struct file *file) lo->lo_min_dio_size = loop_query_min_dio_size(lo); } +static int loop_check_backing_file(struct file *file) +{ + if (!file->f_op->read_iter) + return -EINVAL; + + if ((file->f_mode & FMODE_WRITE) && !file->f_op->write_iter) + return -EINVAL; + + return 0; +} + /* * loop_change_fd switched the backing store of a loopback device to * a new file. This is useful for operating system installers to free up @@ -526,6 +537,10 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev, if (!file) return -EBADF; + error = loop_check_backing_file(file); + if (error) + return error; + /* suppress uevents while reconfiguring the device */ dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 1); @@ -963,6 +978,14 @@ static int loop_configure(struct loop_device *lo, blk_mode_t mode, if (!file) return -EBADF; + + if ((mode & BLK_OPEN_WRITE) && !file->f_op->write_iter) + return -EINVAL; + + error = loop_check_backing_file(file); + if (error) + return error; + is_loop = is_loop_device(file); /* This is safe, since we have a reference from open(). */ |