From: ebiederm@xmission.com (Eric W. Biederman)
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: viro@ZenIV.linux.org.uk, linux-kernel@vger.kernel.org,
linux-pci@vger.kernel.org, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org, hugh@veritas.com, tj@kernel.org,
adobriyan@gmail.com, torvalds@linux-foundation.org,
alan@lxorguk.ukuu.org.uk, gregkh@suse.de, npiggin@suse.de,
akpm@linux-foundation.org, hch@infradead.org
Subject: Re: [PATCH 0/23] File descriptor hot-unplug support v2
Date: Mon, 08 Jun 2009 23:31:16 -0700 [thread overview]
Message-ID: <m1tz2pyl3f.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <E1MDuEI-0006BC-1C@pomaz-ex.szeredi.hu> (Miklos Szeredi's message of "Tue\, 09 Jun 2009 07\:50\:38 +0200")
Miklos Szeredi <miklos@szeredi.hu> writes:
> On Mon, 8 Jun 2009, Al Viro wrote:
>> On Mon, Jun 08, 2009 at 06:44:41PM +0200, Miklos Szeredi wrote:
>>
>> > I'm still not getting what the problem is. AFAICS file operations are
>> > either
>> >
>> > a) non-interruptible but finish within a short time or
>> > b) may block indefinitely but are interruptible (or at least killable).
>> >
>> > Anything else is already problematic, resulting in processes "stuck in
>> > D state".
>>
>> Welcome to reality...
>>
>> * bread() is non-interruptible
>> * so's copy_from_user()/copy_to_user()
>
> And why should revoke(2) care? Just wait for the damn thing to
> finish. Why exactly do these need to be interruptible?
Agreed. I expect the data size is going to be a page or less. Which
is at most 64K on some weird architectures. I think that counts as a
short time waiting for disk I/O. Baring thrashing.
> Okay, if we want revoke or umount -f to be instantaneous then all that
> needs to be taken care of. But does it *need* to be?
Good question. I wonder what umount -f needs when we yank out a usb drive.
> My idea of revoke is something like below:
>
> - make sure no new operations are started on the file
> - check state of tasks for ongoing operations, if interruptible send signal
Figuring out who to send a signal to is tricky. Still it should be doable
in the common case.
> - wait for all pending operations to finish
> - kill file
Eric
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2009-06-09 6:31 UTC|newest]
Thread overview: 99+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-11 12:01 [RFC][PATCH 0/9] File descriptor hot-unplug support Eric W. Biederman
2009-04-11 12:03 ` [RFC][PATCH 1/9] mm: Introduce remap_file_mappings Eric W. Biederman
2009-04-11 12:05 ` [RFC][PATCH 2/9] mm: Implement generic support for revoking a mapping Eric W. Biederman
2009-04-11 12:06 ` [RFC][PATCH 3/9] sysfs: Use remap_file_mappings Eric W. Biederman
2009-04-11 12:07 ` [RFC][PATCH 4/9] vfs: Generalize the file_list Eric W. Biederman
2009-04-11 12:08 ` [RFC][PATCH 5/9] vfs: Introduce basic infrastructure for revoking a file Eric W. Biederman
2009-04-14 22:12 ` Jonathan Corbet
2009-04-15 2:55 ` Eric W. Biederman
2009-04-11 12:10 ` [RFC][PATCH 6/9] vfs: Utilize fops_read_lock where appropriate Eric W. Biederman
2009-04-11 12:11 ` [RFC][PATCH 7/9] vfs: Optimize fops_read_lock Eric W. Biederman
2009-04-11 12:13 ` [RFC][PATCH 8/9] vfs: Implement generic revoked file operations Eric W. Biederman
2009-04-12 18:56 ` Jamie Lokier
2009-04-12 20:04 ` Eric W. Biederman
2009-04-12 20:31 ` Jamie Lokier
2009-04-12 21:53 ` Eric W. Biederman
2009-04-12 20:54 ` Eric W. Biederman
2009-04-12 21:02 ` Jamie Lokier
2009-04-12 23:06 ` Eric W. Biederman
2009-04-11 12:14 ` [RFC][PATCH 9/9] proc: Use the generic vfs revoke facility that now exists Eric W. Biederman
2009-04-11 15:58 ` [RFC][PATCH 0/9] File descriptor hot-unplug support Al Viro
2009-04-11 16:49 ` Eric W. Biederman
2009-04-11 16:56 ` Al Viro
2009-04-11 23:57 ` Eric W. Biederman
2009-04-12 20:21 ` Eric W. Biederman
2009-04-14 3:16 ` Tejun Heo
2009-04-14 7:39 ` Eric W. Biederman
2009-04-14 7:45 ` Tejun Heo
2009-04-14 8:27 ` Eric W. Biederman
2009-04-14 8:49 ` Tejun Heo
2009-04-14 15:07 ` Jamie Lokier
2009-04-14 19:09 ` Eric W. Biederman
2009-06-01 21:45 ` [PATCH 0/23] File descriptor hot-unplug support v2 Eric W. Biederman
2009-06-01 21:50 ` [PATCH 01/23] mm: Introduce revoke_file_mappings Eric W. Biederman
2009-06-01 22:25 ` Andrew Morton
2009-06-02 0:12 ` Eric W. Biederman
2009-06-01 21:50 ` [PATCH 02/23] vfs: Implement unpoll_file Eric W. Biederman
2009-06-06 8:08 ` Al Viro
2009-06-01 21:50 ` [PATCH 03/23] vfs: Generalize the file_list Eric W. Biederman
2009-06-02 7:06 ` Nick Piggin
2009-06-05 19:33 ` Eric W. Biederman
2009-06-09 10:38 ` Nick Piggin
2009-06-09 18:38 ` Eric W. Biederman
2009-06-10 6:05 ` Nick Piggin
2009-06-01 21:50 ` [PATCH 04/23] vfs: Introduce infrastructure for revoking a file Eric W. Biederman
2009-06-02 5:16 ` Pekka Enberg
2009-06-02 6:51 ` Eric W. Biederman
2009-06-02 7:08 ` Pekka Enberg
2009-06-02 7:14 ` Nick Piggin
2009-06-02 17:06 ` Linus Torvalds
2009-06-02 20:52 ` Eric W. Biederman
2009-06-03 6:37 ` Nick Piggin
2009-06-02 22:56 ` Eric W. Biederman
2009-06-03 6:38 ` Nick Piggin
2009-06-05 9:03 ` Miklos Szeredi
2009-06-05 19:06 ` Eric W. Biederman
2009-06-01 21:50 ` [PATCH 05/23] vfs: Teach lseek to use file_hotplug_lock Eric W. Biederman
2009-06-01 21:50 ` [PATCH 06/23] vfs: Teach read/write to use file_hotplug_read_lock Eric W. Biederman
2009-06-01 21:50 ` [PATCH 07/23] vfs: Teach sendfile,splice,tee,and vmsplice to use file_hotplug_lock Eric W. Biederman
2009-06-03 23:39 ` Badari Pulavarty
2009-06-05 19:37 ` Eric W. Biederman
2009-06-01 21:50 ` [PATCH 08/23] vfs: Teach readdir " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 09/23] vfs: Teach poll and select " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 10/23] vfs: Teach do_path_lookup " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 11/23] mm: Teach mmap " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 12/23] vfs: Teach fcntl " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 13/23] vfs: Teach ioctl " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 14/23] vfs: Teach flock " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 15/23] vfs: Teach fallocate, and filp_close " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 16/23] vfs: Teach fstatfs, fstatfs64, ftruncate, fchdir, fchmod, fchown " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 17/23] proc: Teach /proc/<pid>/fd " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 18/23] vfs: Teach epoll " Eric W. Biederman
2009-06-02 16:51 ` Davide Libenzi
2009-06-02 21:23 ` Eric W. Biederman
2009-06-02 21:52 ` Davide Libenzi
2009-06-02 22:51 ` Eric W. Biederman
2009-06-03 14:57 ` Davide Libenzi
2009-06-03 20:53 ` Eric W. Biederman
2009-06-04 0:50 ` Davide Libenzi
2009-06-04 1:42 ` Eric W. Biederman
2009-06-01 21:50 ` [PATCH 19/23] eventpoll: Fix comment Eric W. Biederman
2009-06-01 21:50 ` [PATCH 20/23] vfs: Teach aio to use file_hotplug_lock Eric W. Biederman
2009-06-01 21:50 ` [PATCH 21/23] vfs: Teach fsync " Eric W. Biederman
2009-06-01 21:50 ` [PATCH 22/23] vfs: Teach fadvice to file_hotplug_lock Eric W. Biederman
2009-06-01 21:50 ` [PATCH 23/23] vfs: Teach readahead to use the file_hotplug_lock Eric W. Biederman
2009-06-03 23:25 ` Badari Pulavarty
2009-06-06 8:03 ` [PATCH 0/23] File descriptor hot-unplug support v2 Al Viro
2009-06-08 9:41 ` Miklos Szeredi
2009-06-08 10:24 ` Jamie Lokier
2009-06-08 16:29 ` Al Viro
2009-06-08 16:44 ` Miklos Szeredi
2009-06-08 17:50 ` Al Viro
2009-06-08 18:01 ` Linus Torvalds
2009-06-08 18:50 ` Al Viro
2009-06-08 19:18 ` Linus Torvalds
2009-06-09 6:42 ` Eric W. Biederman
2009-06-09 10:52 ` Nick Piggin
2009-06-09 5:50 ` Miklos Szeredi
2009-06-09 6:31 ` Eric W. Biederman [this message]
2009-06-09 6:22 ` Eric W. Biederman
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=m1tz2pyl3f.fsf@fess.ebiederm.org \
--to=ebiederm@xmission.com \
--cc=adobriyan@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=alan@lxorguk.ukuu.org.uk \
--cc=gregkh@suse.de \
--cc=hch@infradead.org \
--cc=hugh@veritas.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-pci@vger.kernel.org \
--cc=miklos@szeredi.hu \
--cc=npiggin@suse.de \
--cc=tj@kernel.org \
--cc=torvalds@linux-foundation.org \
--cc=viro@ZenIV.linux.org.uk \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).