On Sat, Jul 9, 2022 at 11:45 AM Shyam Prasad N <nspmangalore@xxxxxxxxx> wrote: > > Hi Steve/Ronnie, > > I'm seeing a strange problem with deferred close. > This is the test that I'm running: > 1. mount a share with actime=600 > 2. open a file in the share so that a handle is opened, and it gets > scheduled for deferred close. > 3. umount the share. That works. > 4. rmmod cifs does not seem to work. It says module cifs is in use. > DebugData shows that tcon/ses/connections are all active for the > unmounted share. > > I think I understand why this happens, but need help understanding how > to fix this. > > Each handle open takes a reference on tcon, and also on the > superblock. So even when the mount point is umounted, tcon does not > get freed. I see that it gets freed when all handles that are deferred > for close are actually closed. > > I tried calling cifs_close_all_deferred_files for the tcon in > cifs_umount_begin. I even tried printing a log there. I did not see > that getting logged during umount. Does that mean umount_begin is not > getting called? > > Wondering what is the correct way to fix this? Ideally, we should call > cifs_close_all_deferred_files as soon as the share is umounted. Which > is the first callback in cifs.ko for this. I was assuming that > umount_begin is that callback. But my experiments are not seeing that > getting called. > > -- > Regards, > Shyam I checked the VFS code. It looks like the umount_begin callback gets called only when called with "umount --force" option. I tested that. It seems to work. Is it the expected though without force? Doesn't seem right to me. -- Regards, Shyam
