From: Al Viro <viro@ZenIV.linux.org.uk>
To: NeilBrown <neilb@suse.com>
Cc: Kinglong Mee <kinglongmee@gmail.com>,
"J. Bruce Fields" <bfields@fieldses.org>,
"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
linux-fsdevel@vger.kernel.org,
Trond Myklebust <trond.myklebust@primarydata.com>
Subject: Re: [PATCH 10/10 v7] nfsd: Allows user un-mounting filesystem where nfsd exports base on
Date: Mon, 13 Jul 2015 05:45:53 +0100 [thread overview]
Message-ID: <20150713044553.GN17109@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20150713142059.493a790e@noble>
On Mon, Jul 13, 2015 at 02:20:59PM +1000, NeilBrown wrote:
> Actually, with that change to pin_kill, this side of things becomes
> really easy.
> All expXXX_pin_kill needs to do is call your new cache_delete_entry.
> If that doesn't cause the entry to be put, then something else has a
> temporary reference which will be put soon. In any case, pin_kill()
> will wait long enough, but not indefinitely.
> No need for kref_get_unless_zero() or any of that.
No. You are seriously misunderstanding what ->kill() is for and what the
existing instances are doing. Again, there is no promise whatsoever that
the object containing fs_pin instance will *survive* past ->kill().
At all.
RTFS, please. What is sorely missing in this recurring patchset is a clear
description of lifetime rules and ordering (who waits for whom and how long).
For all the objects involved.
WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
To: NeilBrown <neilb-IBi9RG/b67k@public.gmane.org>
Cc: Kinglong Mee
<kinglongmee-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
"J. Bruce Fields"
<bfields-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>,
"linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Trond Myklebust
<trond.myklebust-7I+n7zu2hftEKMMhf/gKZA@public.gmane.org>
Subject: Re: [PATCH 10/10 v7] nfsd: Allows user un-mounting filesystem where nfsd exports base on
Date: Mon, 13 Jul 2015 05:45:53 +0100 [thread overview]
Message-ID: <20150713044553.GN17109@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20150713142059.493a790e@noble>
On Mon, Jul 13, 2015 at 02:20:59PM +1000, NeilBrown wrote:
> Actually, with that change to pin_kill, this side of things becomes
> really easy.
> All expXXX_pin_kill needs to do is call your new cache_delete_entry.
> If that doesn't cause the entry to be put, then something else has a
> temporary reference which will be put soon. In any case, pin_kill()
> will wait long enough, but not indefinitely.
> No need for kref_get_unless_zero() or any of that.
No. You are seriously misunderstanding what ->kill() is for and what the
existing instances are doing. Again, there is no promise whatsoever that
the object containing fs_pin instance will *survive* past ->kill().
At all.
RTFS, please. What is sorely missing in this recurring patchset is a clear
description of lifetime rules and ordering (who waits for whom and how long).
For all the objects involved.
--
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next prev parent reply other threads:[~2015-07-13 4:45 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-11 12:46 [PATCH 00/10 v7] NFSD: Pin to vfsmount for nfsd exports cache Kinglong Mee
2015-07-11 12:46 ` Kinglong Mee
2015-07-11 12:47 ` [PATCH 01/10 v7] fs_pin: Initialize value for fs_pin explicitly Kinglong Mee
2015-07-11 12:47 ` Kinglong Mee
2015-07-11 12:47 ` [PATCH 02/10 v7] fs_pin: Export functions for specific filesystem Kinglong Mee
2015-07-11 12:47 ` Kinglong Mee
2015-07-11 12:48 ` [PATCH 03/10 v7] path: New helpers path_get_pin/path_put_unpin for path pin Kinglong Mee
2015-07-11 12:48 ` Kinglong Mee
2015-07-11 12:48 ` [PATCH 04/10 v7] fs: New helper legitimize_mntget() for getting a legitimize mnt Kinglong Mee
2015-07-11 12:48 ` Kinglong Mee
2015-07-11 12:49 ` [PATCH 05/10 v7] sunrpc: Store cache_detail in seq_file's private, directly Kinglong Mee
2015-07-11 12:49 ` [PATCH 06/10 v7] sunrpc/nfsd: Remove redundant code by exports seq_operations functions Kinglong Mee
2015-07-11 12:50 ` [PATCH 07/10 v7] sunrpc: Switch to using list_head instead single list Kinglong Mee
2015-07-11 12:50 ` Kinglong Mee
2015-07-11 12:54 ` Christoph Hellwig
2015-07-11 12:54 ` Christoph Hellwig
2015-07-13 1:30 ` NeilBrown
2015-07-13 8:27 ` Kinglong Mee
2015-07-13 8:27 ` Kinglong Mee
2015-07-11 12:51 ` [PATCH 08/10 v7] sunrpc: New helper cache_delete_entry for deleting cache_head directly Kinglong Mee
2015-07-11 12:51 ` [PATCH 09/10 v7] sunrpc: Support get_ref/put_ref for reference change in cache_head Kinglong Mee
2015-07-11 12:51 ` Kinglong Mee
2015-07-11 12:52 ` [PATCH 10/10 v7] nfsd: Allows user un-mounting filesystem where nfsd exports base on Kinglong Mee
2015-07-11 12:52 ` Kinglong Mee
2015-07-13 3:39 ` NeilBrown
2015-07-13 3:39 ` NeilBrown
2015-07-13 4:02 ` Al Viro
2015-07-13 5:19 ` NeilBrown
2015-07-13 5:19 ` NeilBrown
2015-07-13 6:02 ` Al Viro
2015-07-13 6:02 ` Al Viro
2015-07-13 4:20 ` NeilBrown
2015-07-13 4:45 ` Al Viro [this message]
2015-07-13 4:45 ` Al Viro
2015-07-13 5:21 ` NeilBrown
2015-07-13 5:21 ` NeilBrown
2015-07-13 6:02 ` NeilBrown
2015-07-13 6:02 ` NeilBrown
2015-07-13 6:08 ` Al Viro
2015-07-13 6:08 ` Al Viro
2015-07-13 6:32 ` NeilBrown
2015-07-13 6:32 ` NeilBrown
2015-07-13 6:43 ` Al Viro
2015-07-13 6:43 ` Al Viro
2015-07-15 3:49 ` NeilBrown
2015-07-15 4:57 ` Al Viro
2015-07-15 4:57 ` Al Viro
2015-07-15 6:51 ` NeilBrown
2015-07-24 2:05 ` NeilBrown
2015-07-27 2:28 ` Kinglong Mee
2015-07-27 2:51 ` NeilBrown
2015-07-27 2:51 ` NeilBrown
2015-07-27 3:17 ` Kinglong Mee
2015-07-15 21:07 ` J. Bruce Fields
2015-07-15 21:07 ` J. Bruce Fields
2015-07-15 23:40 ` NeilBrown
2015-07-15 23:40 ` NeilBrown
2015-07-16 20:51 ` J. Bruce Fields
2015-07-16 20:51 ` J. Bruce Fields
2015-07-21 21:58 ` NeilBrown
2015-07-21 21:58 ` NeilBrown
2015-07-22 15:08 ` J. Bruce Fields
2015-07-22 15:08 ` J. Bruce Fields
2015-07-23 23:46 ` export table lookup: was " NeilBrown
2015-07-23 23:46 ` NeilBrown
2015-07-24 19:48 ` J. Bruce Fields
2015-07-24 19:48 ` J. Bruce Fields
2015-07-25 0:40 ` NeilBrown
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