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[1/7] namespace: fix clone_private_mount() kernel doc

Message ID 20210414123750.2110159-2-brauner@kernel.org (mailing list archive)
State New, archived
Headers show
Series fs: tweak and switch more fses to private mounts | expand

Commit Message

Christian Brauner April 14, 2021, 12:37 p.m. UTC 
From: Christian Brauner <christian.brauner@ubuntu.com>

Extend the kernel documentation for clone_private_mount(). Add some more
detailed info about its usage and convert it into proper kernel doc.

Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---
 fs/namespace.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)
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Patch

diff --git a/fs/namespace.c b/fs/namespace.c
index 56bb5a5fdc0d..02f415061efe 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1939,12 +1939,21 @@  void drop_collected_mounts(struct vfsmount *mnt)
 
 /**
  * clone_private_mount - create a private clone of a path
+ * @path: path from which the mnt to clone will be taken
  *
- * This creates a new vfsmount, which will be the clone of @path.  The new will
- * not be attached anywhere in the namespace and will be private (i.e. changes
- * to the originating mount won't be propagated into this).
+ * This creates a new vfsmount, which will be a clone of @path's vfsmount.
  *
- * Release with mntput().
+ * In contrast to mnt_clone_internal() the new mount will not be marked
+ * MNT_INTERNAL but will have MNT_NS_INTERNAL attached as its mount namespace
+ * making it suitable for long-term mounts since mntput()ing it will always hit
+ * the fastpath as long as kern_unmount() hasn't been called.
+ *
+ * Since the mount is not reachable anwyhere mount properties and propagation
+ * properties remain stable, i.e. cannot change.
+ *
+ * Useable with mntget()/mntput() but needs to be released with kern_unmount().
+ *
+ * Return: A clone of @path's vfsmount on success, an error pointer on failure.
  */
 struct vfsmount *clone_private_mount(const struct path *path)
 {