Merge tag 'pull-18-rc1-work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull mount handling updates from Al Viro:
 "Cleanups (and one fix) around struct mount handling.

  The fix is usermode_driver.c one - once you've done kern_mount(), you
  must kern_unmount(); simple mntput() will end up with a leak. Several
  failure exits in there messed up that way... In practice you won't hit
  those particular failure exits without fault injection, though"

* tag 'pull-18-rc1-work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  move mount-related externs from fs.h to mount.h
  blob_to_mnt(): kern_unmount() is needed to undo kern_mount()
  m->mnt_root->d_inode->i_sb is a weird way to spell m->mnt_sb...
  linux/mount.h: trim includes
  uninline may_mount() and don't opencode it in fspick(2)/fsopen(2)

4 files changed, 6 insertions, 5 deletions

diff --git a/fs/fsopen.c b/fs/fsopen.c
index 27a890aa493a..fc9d2d9fd234 100644
--- a/fs/fsopen.c
+++ b/fs/fsopen.c
@@ -119,7 +119,7 @@ SYSCALL_DEFINE2(fsopen, const char __user *, _fs_name, unsigned int, flags)
 	const char *fs_name;
 	int ret;
 
-	if (!ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN))
+	if (!may_mount())
 		return -EPERM;
 
 	if (flags & ~FSOPEN_CLOEXEC)
@@ -162,7 +162,7 @@ SYSCALL_DEFINE3(fspick, int, dfd, const char __user *, path, unsigned int, flags
 	unsigned int lookup_flags;
 	int ret;
 
-	if (!ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN))
+	if (!may_mount())
 		return -EPERM;
 
 	if ((flags & ~(FSPICK_CLOEXEC |
diff --git a/fs/internal.h b/fs/internal.h
index ad77723779f9..87e96b9024ce 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -84,6 +84,7 @@ extern int __mnt_want_write_file(struct file *);
 extern void __mnt_drop_write_file(struct file *);
 
 extern void dissolve_on_fput(struct vfsmount *);
+extern bool may_mount(void);
 
 int path_mount(const char *dev_name, struct path *path,
 		const char *type_page, unsigned long flags, void *data_page);
diff --git a/fs/namespace.c b/fs/namespace.c
index 41461f55c039..e6a7e769d25d 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1760,7 +1760,7 @@ out_unlock:
 /*
  * Is the caller allowed to modify his namespace?
  */
-static inline bool may_mount(void)
+bool may_mount(void)
 {
 	return ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN);
 }
diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c
index 7b861e4f0533..03d3a270eff4 100644
--- a/fs/nfs/nfs4file.c
+++ b/fs/nfs/nfs4file.c
@@ -328,7 +328,7 @@ static struct file *__nfs42_ssc_open(struct vfsmount *ss_mnt,
 	char *read_name = NULL;
 	int len, status = 0;
 
-	server = NFS_SERVER(ss_mnt->mnt_root->d_inode);
+	server = NFS_SB(ss_mnt->mnt_sb);
 
 	if (!fattr)
 		return ERR_PTR(-ENOMEM);
@@ -346,7 +346,7 @@ static struct file *__nfs42_ssc_open(struct vfsmount *ss_mnt,
 		goto out;
 	snprintf(read_name, len, SSC_READ_NAME_BODY, read_name_gen++);
 
-	r_ino = nfs_fhget(ss_mnt->mnt_root->d_inode->i_sb, src_fh, fattr);
+	r_ino = nfs_fhget(ss_mnt->mnt_sb, src_fh, fattr);
 	if (IS_ERR(r_ino)) {
 		res = ERR_CAST(r_ino);
 		goto out_free_name;