From mboxrd@z Thu Jan 1 00:00:00 1970 From: Randy Dunlap Subject: Re: [PATCH 2/6] Adjust watch_queue documentation to mention mount and superblock watches. [ver #5] Date: Sun, 30 Jun 2019 19:59:33 -0700 Message-ID: <7a288c2c-11a1-87df-9550-b247d6ce3010@infradead.org> References: <156173701358.15650.8735203424342507015.stgit@warthog.procyon.org.uk> <156173703546.15650.14319137940607993268.stgit@warthog.procyon.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <156173703546.15650.14319137940607993268.stgit@warthog.procyon.org.uk> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: David Howells , viro@zeniv.linux.org.uk Cc: Casey Schaufler , Stephen Smalley , Greg Kroah-Hartman , nicolas.dichtel@6wind.com, raven@themaw.net, Christian Brauner , keyrings@vger.kernel.org, linux-usb@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-api@vger.kernel.org Hi David, On 6/28/19 8:50 AM, David Howells wrote: > Signed-off-by: David Howells > --- > > Documentation/watch_queue.rst | 20 +++++++++++++++++++- > drivers/misc/Kconfig | 5 +++-- > 2 files changed, 22 insertions(+), 3 deletions(-) > > diff --git a/Documentation/watch_queue.rst b/Documentation/watch_queue.rst > index 4087a8e670a8..1bec2018d549 100644 > --- a/Documentation/watch_queue.rst > +++ b/Documentation/watch_queue.rst > @@ -13,6 +13,10 @@ receive notifications from the kernel. This can be used in conjunction with:: > > * USB subsystem event notifications > > + * Mount topology change notifications > + > + * Superblock event notifications > + > > The notifications buffers can be enabled by: > > @@ -324,6 +328,19 @@ Any particular buffer can be fed from multiple sources. Sources include: > for buses and devices. Watchpoints of this type are set on the global > device watch list. > > + * WATCH_TYPE_MOUNT_NOTIFY > + > + Notifications of this type indicate mount tree topology changes and mount > + attribute changes. A watch can be set on a particular file or directory > + and notifications from the path subtree rooted at that point will be > + intercepted. > + > + * WATCH_TYPE_SB_NOTIFY > + > + Notifications of this type indicate superblock events, such as quota limits > + being hit, I/O errors being produced or network server loss/reconnection. > + Watches of this type are set directly on superblocks. > + > > Event Filtering > =============== > @@ -365,7 +382,8 @@ Where: > (watch.info & info_mask) == info_filter > > This could be used, for example, to ignore events that are not exactly on > - the watched point in a mount tree. > + the watched point in a mount tree by specifying NOTIFY_MOUNT_IN_SUBTREE > + must be 0. I'm having a little trouble parsing that sentence. Could you clarify it or maybe rewrite/modify it? Thanks. > > * ``subtype_filter`` is a bitmask indicating the subtypes that are of > interest. Bit 0 of subtype_filter[0] corresponds to subtype 0, bit 1 to -- ~Randy