diff options
author | Al Viro <viro@zeniv.linux.org.uk> | 2016-12-16 22:34:52 +0100 |
---|---|---|
committer | Al Viro <viro@zeniv.linux.org.uk> | 2016-12-16 22:34:52 +0100 |
commit | 9763f7a4a5f7b1a7c480fa06d01b2bad25163c0a (patch) | |
tree | 63e3f777b699ec26761eab948c40d70bba1476b0 /fs/namespace.c | |
parent | Merge remote-tracking branch 'djwong/ocfs2-vfs-reflink-6' into for-linus (diff) | |
parent | autofs - dont hold spin lock over direct mount expire (diff) | |
download | linux-9763f7a4a5f7b1a7c480fa06d01b2bad25163c0a.tar.xz linux-9763f7a4a5f7b1a7c480fa06d01b2bad25163c0a.zip |
Merge branch 'work.autofs' into for-linus
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/namespace.c')
-rw-r--r-- | fs/namespace.c | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index 9ad88a45b3e3..f7e28f8ea04d 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1159,6 +1159,35 @@ struct vfsmount *mntget(struct vfsmount *mnt) } EXPORT_SYMBOL(mntget); +/* path_is_mountpoint() - Check if path is a mount in the current + * namespace. + * + * d_mountpoint() can only be used reliably to establish if a dentry is + * not mounted in any namespace and that common case is handled inline. + * d_mountpoint() isn't aware of the possibility there may be multiple + * mounts using a given dentry in a different namespace. This function + * checks if the passed in path is a mountpoint rather than the dentry + * alone. + */ +bool path_is_mountpoint(const struct path *path) +{ + unsigned seq; + bool res; + + if (!d_mountpoint(path->dentry)) + return false; + + rcu_read_lock(); + do { + seq = read_seqbegin(&mount_lock); + res = __path_is_mountpoint(path); + } while (read_seqretry(&mount_lock, seq)); + rcu_read_unlock(); + + return res; +} +EXPORT_SYMBOL(path_is_mountpoint); + struct vfsmount *mnt_clone_internal(const struct path *path) { struct mount *p; |