From: "Aurélien Aptel" <aaptel@suse.com>
To: Shyam Prasad N <nspmangalore@gmail.com>
Cc: CIFS <linux-cifs@vger.kernel.org>,
linux-fsdevel@vger.kernel.org, Steve French <smfrench@gmail.com>,
Paulo Alcantara <pc@cjr.nz>
Subject: Re: [PATCH v1] cifs: make nested cifs mount point dentries always valid to deal with signaled 'df'
Date: Tue, 02 Feb 2021 12:00:16 +0100 [thread overview]
Message-ID: <87v9ba91kv.fsf@suse.com> (raw)
In-Reply-To: <CANT5p=oSrrCbCdXZSbjmPDM4P=z=1c=kj9w1DDTJO5UhtREo8g@mail.gmail.com>
Shyam Prasad N <nspmangalore@gmail.com> 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)
next prev parent reply other threads:[~2021-02-02 11:01 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-29 17:13 [PATCH v1] cifs: make nested cifs mount point dentries always valid to deal with signaled 'df' Aurélien Aptel
2021-01-31 9:28 ` Shyam Prasad N
2021-02-01 10:31 ` Aurélien Aptel
2021-02-01 16:51 ` Shyam Prasad N
2021-02-02 11:00 ` Aurélien Aptel [this message]
2021-02-02 11:16 ` [PATCH v2] cifs: report error instead of invalid when revalidating a dentry fails Aurélien Aptel
2021-02-02 17:09 ` Shyam Prasad N
2021-02-02 17:34 ` Aurélien Aptel
2021-02-02 17:42 ` [PATCH v3] " Aurélien Aptel
2021-02-02 17:55 ` Steve French
2021-02-02 18:27 ` Shyam Prasad N
2021-02-02 18:26 ` Shyam Prasad N
2021-02-02 18:34 ` Aurélien Aptel
2021-02-03 4:24 ` Shyam Prasad N
2021-02-05 13:32 ` Shyam Prasad N
2021-02-05 14:42 ` [PATCH v4] " Aurélien Aptel
2021-02-05 14:52 ` Shyam Prasad N
2021-02-05 19:22 ` Steve French
2021-02-05 22:31 ` Steve French
2021-02-03 4:11 ` [PATCH v3] " Steve French
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87v9ba91kv.fsf@suse.com \
--to=aaptel@suse.com \
--cc=linux-cifs@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=nspmangalore@gmail.com \
--cc=pc@cjr.nz \
--cc=smfrench@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.