On Tue, Feb 07, 2023 at 10:02:51AM +0800, Zhongjie Zhu wrote: > On Mon, Feb 6, 2023 at 11:17 PM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > > > On Mon, Feb 06, 2023 at 11:33:15AM +0800, 朱忠杰 wrote: > > > Yes, this is a very special case. > > > > > > It will happen only when disconnecting the mass storage if there are > > > too many files in the storage, and the scanning operation is running, > > > and the file system is not unmounted. > > > It looks like this issue should be fixed in the usb mass storage > > > driver, but I don't find an appropriate place. > > > > That's not surprising, because usb-storage doesn't know anything about > > what's happening on the mass-storage device it connects to. All it does > > is send the commands that it gets from the SCSI subsystem to the device > > and receive the results back. It has no idea whether there is a mounted > > filesystem on the device, if the filesystem contains any files, or > > whether a scanning operation is running, > > > > A better place to look for fixing this might be the filesystem code. > > That's where the information about mounting, files, and scanning can be > > found. > > > > Alan Stern > > The problem is there is a for loop in the invalidate_inodes(), this > function is in the block device driver. when the usb_disconnect is > called, the filesystem is not umounted, userspace applications will be > noticed the usb storage is disconnected, and then do the umounting > work. > the invalidate_inodes() is called in the usb hub worker, and will run > for a long time. To fix this issue, the long running loop need to be > moved out from the usb hub worker. Oh, maybe I didn't understand. You've got a USB mass-storage device with a mounted filesystem and a lot of dirty inodes, right? Then a USB disconnect happens, and as part of the disconnect processing, invalidate_inodes() runs for a long time. Do you know why it takes so long? The I/O operations shouldn't need any time; they will all fail immediately because the device has been disconnected and so there is no way to communicate with it. Alan Stern
