Shyam Prasad N <nspmangalore@xxxxxxxxx> writes: > But the point that I'm trying to make here is that VFS reacts > differently when d_validate returns an error VS when it just returns > invalid: > https://elixir.bootlin.com/linux/latest/source/fs/namei.c#L1409 I've tried returning the error with the repro script and it also worked. > Notice how it calls d_invalidate only when there's no error. And > d_invalidate seems to have detach_mounts. > It is likely that the umount happens there. I've dumped call stacks, the revalidation is triggered by filename_lookup() [ 31.913092] [<ffffffff8133e3d1>] ? SendReceive+0x2b1/0x2d0 [ 31.913093] [<ffffffff8132cbd2>] ? CIFSSMBQPathInfo+0x152/0x260 [ 31.913096] [<ffffffff81343c9f>] ? cifs_query_path_info+0x6f/0x1a0 [ 31.913098] [<ffffffff81366953>] ? cifs_get_inode_info.cold+0x44f/0x6bb [ 31.913100] [<ffffffff810bf935>] ? wake_up_process+0x15/0x20 [ 31.913102] [<ffffffff810e9c30>] ? vprintk_emit+0x200/0x500 [ 31.913103] [<ffffffff810ea099>] ? vprintk_default+0x29/0x40 [ 31.913105] [<ffffffff811a896f>] ? printk+0x50/0x52 [ 31.913107] [<ffffffff813678c1>] ? cifs_revalidate_dentry_attr.cold+0x71/0x79 [ 31.913109] [<ffffffff8133b194>] ? cifs_revalidate_dentry+0x14/0x30 [ 31.913110] [<ffffffff813327e5>] ? cifs_d_revalidate+0x25/0xb0 [ 31.913112] [<ffffffff812404ff>] ? lookup_fast+0x1bf/0x220 [ 31.913113] [<ffffffff812407bc>] ? walk_component+0x3c/0x3f0 [ 31.913114] [<ffffffff8123fe5b>] ? path_init+0x23b/0x450 [ 31.913116] [<ffffffff812412bf>] ? path_lookupat+0x7f/0x110 [ 31.913118] [<ffffffff81242ae7>] ? filename_lookup+0x97/0x190 [ 31.913120] [<ffffffff811e1e39>] ? handle_pte_fault+0x1d9/0x240 [ 31.913122] [<ffffffff81242cc9>] ? user_path_at_empty+0x59/0x90 [ 31.913124] [<ffffffff8126ab59>] ? user_statfs+0x39/0xa0 [ 31.913125] [<ffffffff8126abd6>] ? SYSC_statfs+0x16/0x40 [ 31.913127] [<ffffffff8106de53>] ? trace_do_page_fault+0x43/0x150 [ 31.913130] [<ffffffff8180359c>] ? async_page_fault+0x3c/0x60 [ 31.913131] [<ffffffff8126ad6e>] ? SyS_statfs+0xe/0x10 [ 31.913132] [<ffffffff81800021>] ? entry_SYSCALL_64_fastpath+0x20/0xee d_invalidate()->...->drop_mountpoint() adds a callback to unmount at later times: [ 31.913246] [<ffffffff812554da>] ? drop_mountpoint+0x6a/0x70 [ 31.913247] [<ffffffff8126b0b8>] ? pin_kill+0x88/0x160 [ 31.913249] [<ffffffff810d6a20>] ? prepare_to_wait_event+0x100/0x100 [ 31.913250] [<ffffffff810d6a20>] ? prepare_to_wait_event+0x100/0x100 [ 31.913252] [<ffffffff8126b205>] ? group_pin_kill+0x25/0x50 [ 31.913253] [<ffffffff812564fa>] ? __detach_mounts+0x13a/0x140 [ 31.913255] [<ffffffff8124bf24>] ? d_invalidate+0xa4/0x100 [ 31.913256] [<ffffffff812404cd>] ? lookup_fast+0x18d/0x220 [ 31.913257] [<ffffffff812407bc>] ? walk_component+0x3c/0x3f0 [ 31.913258] [<ffffffff8123fe5b>] ? path_init+0x23b/0x450 [ 31.913259] [<ffffffff812412bf>] ? path_lookupat+0x7f/0x110 [ 31.913261] [<ffffffff81242ae7>] ? filename_lookup+0x97/0x190 [ 31.913262] [<ffffffff811e1e39>] ? handle_pte_fault+0x1d9/0x240 [ 31.913263] [<ffffffff81242cc9>] ? user_path_at_empty+0x59/0x90 [ 31.913265] [<ffffffff8126ab59>] ? user_statfs+0x39/0xa0 [ 31.913266] [<ffffffff8126abd6>] ? SYSC_statfs+0x16/0x40 [ 31.913268] [<ffffffff8106de53>] ? trace_do_page_fault+0x43/0x150 [ 31.913269] [<ffffffff8180359c>] ? async_page_fault+0x3c/0x60 [ 31.913270] [<ffffffff8126ad6e>] ? SyS_statfs+0xe/0x10 [ 31.913272] [<ffffffff81800021>] ? entry_SYSCALL_64_fastpath+0x20/0xee The actual unmount call: [ 31.913594] [<ffffffff81362248>] ? cifs_put_tcon.part.0+0x71/0x123 [ 31.913597] [<ffffffff81362309>] ? cifs_put_tlink.cold+0x5/0xa [ 31.913599] [<ffffffff813318a5>] ? cifs_umount+0x65/0xd0 [ 31.913601] [<ffffffff8132976f>] ? cifs_kill_sb+0x1f/0x30 [ 31.913603] [<ffffffff8123527a>] ? deactivate_locked_super+0x4a/0xd0 [ 31.913605] [<ffffffff81235344>] ? deactivate_super+0x44/0x50 [ 31.913609] [<ffffffff81253adb>] ? cleanup_mnt+0x3b/0x90 [ 31.913610] [<ffffffff81253b82>] ? __cleanup_mnt+0x12/0x20 [ 31.913613] [<ffffffff810af9eb>] ? task_work_run+0x7b/0xb0 [ 31.913616] [<ffffffff810a0a3a>] ? get_signal+0x4ea/0x4f0 [ 31.913618] [<ffffffff811e1e39>] ? handle_pte_fault+0x1d9/0x240 [ 31.913621] [<ffffffff810185d1>] ? do_signal+0x21/0x100 [ 31.913624] [<ffffffff81242cc9>] ? user_path_at_empty+0x59/0x90 [ 31.913626] [<ffffffff8126ab59>] ? user_statfs+0x39/0xa0 [ 31.913628] [<ffffffff8126abd6>] ? SYSC_statfs+0x16/0x40 [ 31.913630] [<ffffffff81003517>] ? exit_to_usermode_loop+0x87/0xc0 [ 31.913632] [<ffffffff81003bed>] ? syscall_return_slowpath+0xed/0x180 [ 31.913634] [<ffffffff818001b1>] ? int_ret_from_sys_call+0x8/0x6d > I'm suggesting that we should return errors inside d_validate > handlers, rather than just 0 or 1. > Makes sense? Yes that worked too. I'll send v2. Cheers, -- Aurélien Aptel / SUSE Labs Samba Team GPG: 1839 CB5F 9F5B FB9B AA97 8C99 03C8 A49B 521B D5D3 SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg, DE GF: Felix Imendörffer, Mary Higgins, Sri Rasiah HRB 247165 (AG München)
