On 4/20/20 1:04 AM, Martijn Coenen wrote:
+/**
+ * loop_set_size - sets device size and notifies userspace
+ * @lo: struct loop_device to set the size for
+ * @size: new size of the loop device
+ *
+ * Callers must validate that the size passed into this function fits into
+ * a sector_t.
+ */
+static void loop_set_size(struct loop_device *lo, loff_t size)
+{
+ struct block_device *bdev = lo->lo_device;
+
+ set_capacity(lo->lo_disk, size);
+ bd_set_size(bdev, size << 9);
+ /* let user-space know about the new size */
+ kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);
+}
How about using the SECTOR_SHIFT constant instead of "9"? I think the
following has been added recently in include/linux/blkdev.h:
#define SECTOR_SHIFT 9
@@ -1295,6 +1321,15 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
/* I/O need to be drained during transfer transition */
blk_mq_freeze_queue(lo->lo_queue);
+ if (size_changed && lo->lo_device->bd_inode->i_mapping->nrpages) {
+ /* kill_bdev should have truncated all the pages */
+ err = -EAGAIN;
+ pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n",
+ __func__, lo->lo_number, lo->lo_file_name,
+ lo->lo_device->bd_inode->i_mapping->nrpages);
+ goto out_unfreeze;
+ }
+
err = loop_release_xfer(lo);
if (err)
goto out_unfreeze;
Please Cc Jaegeuk for any changes in this code (see also
https://lore.kernel.org/linux-block/20190518005304.GA19446@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/).
Please also change the "kill_bdev should have truncated all the pages"
comment into something like "return -EAGAIN if any pages have been
dirtied after kill_bdev() returned".
Thanks,
Bart.
