From: Christian Brauner <christian@brauner.io>
To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: torvalds@linux-foundation.org, tglx@linutronix.de,
kstewart@linuxfoundation.org, gregkh@linuxfoundation.org,
pombredanne@nexb.com, linux-api@vger.kernel.org,
ebiederm@xmission.com, seth.forshee@canonical.com,
viro@zeniv.linux.org.uk, Christian Brauner <christian@brauner.io>
Subject: [PATCH 3/6 v1 resend] statfs: add ST_UNBINDABLE
Date: Fri, 25 May 2018 14:48:22 +0200 [thread overview]
Message-ID: <20180525124825.23875-4-christian@brauner.io> (raw)
In-Reply-To: <20180525124825.23875-1-christian@brauner.io>
Currently userspace can only determine whether a mountpoint is unbindable
by parsing /proc/<pid>/mountinfo. It would be convenient to simply retrieve
this property with a statvfs() call.
This let's userspace avoid costly parsing, supports cases where /proc is
not mounted, and supports usecases where file descriptors to mountpoints
are passed between processes that are inspected via fstatvfs().
Signed-off-by: Christian Brauner <christian@brauner.io>
---
v0->v1:
* non-functional changes: extend commit message
---
fs/statfs.c | 2 ++
include/linux/statfs.h | 1 +
2 files changed, 3 insertions(+)
diff --git a/fs/statfs.c b/fs/statfs.c
index 5b2a24f0f263..61b3063d3921 100644
--- a/fs/statfs.c
+++ b/fs/statfs.c
@@ -29,6 +29,8 @@ static int flags_by_mnt(int mnt_flags)
flags |= ST_NODIRATIME;
if (mnt_flags & MNT_RELATIME)
flags |= ST_RELATIME;
+ if (mnt_flags & MNT_UNBINDABLE)
+ flags |= ST_UNBINDABLE;
return flags;
}
diff --git a/include/linux/statfs.h b/include/linux/statfs.h
index b336c04e793c..e1b84d0388c1 100644
--- a/include/linux/statfs.h
+++ b/include/linux/statfs.h
@@ -40,5 +40,6 @@ struct kstatfs {
#define ST_NOATIME (1<<10) /* do not update access times */
#define ST_NODIRATIME (1<<11) /* do not update directory access times */
#define ST_RELATIME (1<<12) /* update atime relative to mtime/ctime */
+#define ST_UNBINDABLE (1<<17) /* change to unbindable */
#endif
--
2.17.0
next prev parent reply other threads:[~2018-05-25 12:48 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-25 12:48 [PATCH 0/6 v1 resend] statfs: handle mount propagation Christian Brauner
2018-05-25 12:48 ` [PATCH 1/6 v1 resend] fs: use << for MS_* flags Christian Brauner
2018-05-25 12:48 ` [PATCH 2/6 v1 resend] statfs: use << to align with fs header Christian Brauner
2018-05-25 12:48 ` Christian Brauner [this message]
2018-05-25 12:48 ` [PATCH 4/6 v1 resend] statfs: add ST_SHARED Christian Brauner
2018-05-25 12:48 ` [PATCH 5/6 v1 resend] statfs: add ST_SLAVE Christian Brauner
2018-05-25 12:48 ` [PATCH 6/6 v1 resend] statfs: add ST_PRIVATE Christian Brauner
2018-06-13 14:06 ` [PATCH 0/6 v1 resend] statfs: handle mount propagation Christian Brauner
2018-06-13 14:24 ` Greg KH
2018-06-13 15:07 ` Christian Brauner
2018-07-19 15:30 ` Christian Brauner
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