From: Christian Brauner <christian@brauner.io>
To: David Howells <dhowells@redhat.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>,
Al Viro <viro@ZenIV.linux.org.uk>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5/6] fsmount: do not use legacy MS_ flags
Date: Mon, 24 Sep 2018 01:01:51 +0200 [thread overview]
Message-ID: <20180923230150.32qbjhnnzy56x3yy@brauner.io> (raw)
In-Reply-To: <3868.1537742717@warthog.procyon.org.uk>
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On Sun, Sep 23, 2018 at 11:45:17PM +0100, David Howells wrote:
> Christian Brauner <christian@brauner.io> wrote:
>
> > Of course, I'm not sure what the reasons for all of the other arguments to
> > this function are since it's not yet implemented.
>
> Well, dfd, path and atflags are pretty standard. atflags conveys things like
> AT_EMPTY_PATH or AT_SYMLINK_NOFOLLOW and dfd conveys a file descriptor
> pointing to a vfs object or AT_FDCWD.
>
> > Seems that attr_values and attr_mask could be compacted to a single
> > attr_mask maybe?
>
> If you don't have a mask, you can't really do recursion. Without the mask,
> you have to supply the entire set of options absolutely - and this would get
> stamped on everything in the target range.
>
> With a mask in combination with the set of desired values, you can turn on or
> off a specific subset of the attributes without affecting the rest - without
> needing to know the rest.
Ok, understood. What about passing the different attrs as a struct?
struct mount_attr {
unsigned int attr_cmd,
unsigned int attr_values,
unsigned int attr_mask,
};
mount_setattr(int dfd, const char *path, unsigned int atflags,
struct mount_attr *attr);
I find that to be a little cleaner in all honesty.
One could also add a version argument similar to what we currently do
for vfs fcaps so that kernel and userspace can easily navigate
compabitility when a new member gets added or removed in later releases.
Christian
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next prev parent reply other threads:[~2018-09-24 5:01 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-20 15:12 [PATCH 0/6] mount-api: fixes and cleanups Miklos Szeredi
2018-09-20 15:12 ` [PATCH 1/6] selinux: fold superblock_doinit() into only caller Miklos Szeredi
2018-09-20 15:12 ` [PATCH 2/6] vfs_submount: use SB_SUBMOUNT instead of MS_SUBMOUNT Miklos Szeredi
2018-09-20 15:12 ` [PATCH 3/6] mount: fix regression in setting "subtype" from legacy API Miklos Szeredi
2018-09-20 15:12 ` [PATCH 4/6] fsconfig: parse "subtype" param for old internal API Miklos Szeredi
2018-09-20 15:12 ` [PATCH 5/6] fsmount: do not use legacy MS_ flags Miklos Szeredi
2018-09-20 15:12 ` [PATCH 6/6] fsconfig: rename FSCONFIG_CMD_CREATE to FSCONFIG_CMD_OBTAIN Miklos Szeredi
2018-09-21 14:41 ` [PATCH 1/6] selinux: fold superblock_doinit() into only caller David Howells
2018-09-21 14:45 ` [PATCH 2/6] vfs_submount: use SB_SUBMOUNT instead of MS_SUBMOUNT David Howells
2018-09-21 14:52 ` [PATCH 3/6] mount: fix regression in setting "subtype" from legacy API David Howells
2018-09-21 14:56 ` [PATCH 4/6] fsconfig: parse "subtype" param for old internal API David Howells
2018-09-21 15:07 ` [PATCH 5/6] fsmount: do not use legacy MS_ flags David Howells
2018-09-21 15:28 ` Miklos Szeredi
2018-09-21 15:37 ` David Howells
2018-09-21 15:54 ` Christian Brauner
2018-09-21 16:52 ` David Howells
2018-09-22 13:21 ` Christian Brauner
2018-09-22 15:48 ` David Howells
2018-09-22 16:14 ` Christian Brauner
2018-09-23 22:45 ` David Howells
2018-09-23 23:01 ` Christian Brauner [this message]
2018-09-24 6:50 ` David Howells
2018-09-24 9:47 ` Christian Brauner
2018-09-24 12:37 ` David Howells
2018-09-24 13:18 ` Christian Brauner
2018-09-21 15:11 ` [PATCH 6/6] fsconfig: rename FSCONFIG_CMD_CREATE to FSCONFIG_CMD_OBTAIN David Howells
2018-09-21 15:23 ` Miklos Szeredi
2018-09-21 16:44 ` [PATCH 0/6] mount-api: fixes and cleanups David Howells
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