From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Howells Date: Thu, 02 Apr 2020 15:42:45 +0000 Subject: Re: Upcoming: Notifications, FS notifications and fsinfo() Message-Id: <3072199.1585842165@warthog.procyon.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit List-Id: References: <20200330211700.g7evnuvvjenq3fzm@wittgenstein> <1445647.1585576702@warthog.procyon.org.uk> <2418286.1585691572@warthog.procyon.org.uk> <20200401090445.6t73dt7gz36bv4rh@ws.net.home> <2488530.1585749351@warthog.procyon.org.uk> <2488734.1585749502@warthog.procyon.org.uk> <2590276.1585756914@warthog.procyon.org.uk> <3070724.1585840971@warthog.procyon.org.uk> In-Reply-To: To: Miklos Szeredi Cc: dhowells@redhat.com, Karel Zak , Christian Brauner , Linus Torvalds , Al Viro , dray@redhat.com, Miklos Szeredi , Steven Whitehouse , Jeff Layton , Ian Kent , andres@anarazel.de, keyrings@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Lennart Poettering , Aleksa Sarai Miklos Szeredi wrote: > > ext4_show_mount(), for example, doesn't lock against "mount -o remount", so > > the configuration can be changing whilst it's being rendered to text. > > Does s_umount nest inside namespace_sem? I really don't see the > relation of those locks. If I understand aright what Al has told me, it's a bad idea to do any blocking operation inside of namespace_sem apart from kmalloc(GFP_KERNEL). David