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 4/6 v9] fs: New helper legitimize_mntget() for getting a legitimize mnt
Date: Wed, 19 Aug 2015 06:02:45 +0100 [thread overview]
Message-ID: <20150819050245.GC18890@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20150819145650.46352023@noble>
On Wed, Aug 19, 2015 at 02:56:50PM +1000, NeilBrown wrote:
> If not, we need to clean up and try again.
> To do this we need to check MNT_SYNC_UMOUNT.
> If that is clear it is safe and best to call mntput() on the mnt.
> If it is set, then we just do the mnt_add_count(mnt, -1) and give up
> completely.
It's more subtle, actually. See my reply upthread for details, but
basically we rely on rcu_read_lock() held since before that MNT_SYNC_UMOUNT
had been set, making synchronize_rcu() in namespace_unlock() a guaranteed
delay of the final mntput until after we have returned.
next prev parent reply other threads:[~2015-08-19 5:02 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-18 7:17 [PATCH 0/6 v9] NFSD: Pin to vfsmount for nfsd exports cache Kinglong Mee
2015-08-18 7:17 ` Kinglong Mee
[not found] ` <55D2DBF6.3010406-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2015-08-18 7:18 ` [PATCH 1/6 v9] fs-pin: allow pin_remove() to be called other than from->kill() Kinglong Mee
2015-08-18 7:18 ` Kinglong Mee
2015-08-18 7:19 ` [PATCH 2/6] fs_pin: Export functions for specific filesystem Kinglong Mee
2015-08-18 7:19 ` Kinglong Mee
2015-08-18 7:20 ` [PATCH 3/6 v9] path: New helpers path_get_pin/path_put_unpin for path pin Kinglong Mee
2015-08-18 7:20 ` Kinglong Mee
2015-08-18 7:21 ` [PATCH 4/6 v9] fs: New helper legitimize_mntget() for getting a legitimize mnt Kinglong Mee
2015-08-18 7:21 ` Kinglong Mee
[not found] ` <55D2DD17.7050504-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2015-08-19 4:56 ` NeilBrown
2015-08-19 4:56 ` NeilBrown
2015-08-19 5:02 ` Al Viro [this message]
[not found] ` <20150819050245.GC18890-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2015-08-27 23:02 ` Kinglong Mee
2015-08-27 23:02 ` Kinglong Mee
2015-08-18 7:22 ` [PATCH 5/6 v9] sunrpc: New helper cache_delete_entry for deleting cache_head directly Kinglong Mee
2015-08-18 7:22 ` Kinglong Mee
2015-08-18 7:23 ` [PATCH 6/6 v9] nfsd: Allows user un-mounting filesystem where nfsd exports base on Kinglong Mee
2015-08-18 7:23 ` Kinglong Mee
[not found] ` <55D2DD8F.6070501-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2015-08-19 3:54 ` NeilBrown
2015-08-19 3:54 ` NeilBrown
2015-08-19 4:50 ` Al Viro
2015-08-19 4:50 ` Al Viro
[not found] ` <20150819045059.GB18890-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2015-08-27 23:15 ` Kinglong Mee
2015-08-27 23:15 ` Kinglong Mee
2015-08-18 7:24 ` [PATCH 2/6 v9] fs_pin: Export functions for specific filesystem Kinglong Mee
2015-08-18 7:24 ` Kinglong Mee
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