These changes are the raw update to linux-4.4.6-rt14. Kernel sources

[kvmfornfv.git] / kernel / fs / namespace.c

diff --git a/kernel/fs/namespace.c b/kernel/fs/namespace.c
index 2893702..62588bf 100644 (file)
--- a/kernel/fs/namespace.c
+++ b/kernel/fs/namespace.c
@@ -594,24 +594,35 @@ static void delayed_free_vfsmnt(struct rcu_head *head)
 }
 
 /* call under rcu_read_lock */
-bool legitimize_mnt(struct vfsmount *bastard, unsigned seq)
+int __legitimize_mnt(struct vfsmount *bastard, unsigned seq)
 {
        struct mount *mnt;
        if (read_seqretry(&mount_lock, seq))
-               return false;
+               return 1;
        if (bastard == NULL)
-               return true;
+               return 0;
        mnt = real_mount(bastard);
        mnt_add_count(mnt, 1);
        if (likely(!read_seqretry(&mount_lock, seq)))
-               return true;
+               return 0;
        if (bastard->mnt_flags & MNT_SYNC_UMOUNT) {
                mnt_add_count(mnt, -1);
-               return false;
+               return 1;
+       }
+       return -1;
+}
+
+/* call under rcu_read_lock */
+bool legitimize_mnt(struct vfsmount *bastard, unsigned seq)
+{
+       int res = __legitimize_mnt(bastard, seq);
+       if (likely(!res))
+               return true;
+       if (unlikely(res < 0)) {
+               rcu_read_unlock();
+               mntput(bastard);
+               rcu_read_lock();
        }
-       rcu_read_unlock();
-       mntput(bastard);
-       rcu_read_lock();
        return false;
 }
 
@@ -1219,7 +1230,7 @@ EXPORT_SYMBOL(replace_mount_options);
 /* iterator; we want it to have access to namespace_sem, thus here... */
 static void *m_start(struct seq_file *m, loff_t *pos)
 {
-       struct proc_mounts *p = proc_mounts(m);
+       struct proc_mounts *p = m->private;
 
        down_read(&namespace_sem);
        if (p->cached_event == p->ns->event) {
@@ -1240,7 +1251,7 @@ static void *m_start(struct seq_file *m, loff_t *pos)
 
 static void *m_next(struct seq_file *m, void *v, loff_t *pos)
 {
-       struct proc_mounts *p = proc_mounts(m);
+       struct proc_mounts *p = m->private;
 
        p->cached_mount = seq_list_next(v, &p->ns->list, pos);
        p->cached_index = *pos;
@@ -1254,7 +1265,7 @@ static void m_stop(struct seq_file *m, void *v)
 
 static int m_show(struct seq_file *m, void *v)
 {
-       struct proc_mounts *p = proc_mounts(m);
+       struct proc_mounts *p = m->private;
        struct mount *r = list_entry(v, struct mount, mnt_list);
        return p->show(m, &r->mnt);
 }
@@ -3211,6 +3222,8 @@ static bool fs_fully_visible(struct file_system_type *type, int *new_mnt_flags)
        down_read(&namespace_sem);
        list_for_each_entry(mnt, &ns->list, mnt_list) {
                struct mount *child;
+               int mnt_flags;
+
                if (mnt->mnt.mnt_sb->s_type != type)
                        continue;
 
@@ -3220,17 +3233,30 @@ static bool fs_fully_visible(struct file_system_type *type, int *new_mnt_flags)
                if (mnt->mnt.mnt_root != mnt->mnt.mnt_sb->s_root)
                        continue;
 
+               /* Read the mount flags and filter out flags that
+                * may safely be ignored.
+                */
+               mnt_flags = mnt->mnt.mnt_flags;
+               if (mnt->mnt.mnt_sb->s_iflags & SB_I_NOEXEC)
+                       mnt_flags &= ~(MNT_LOCK_NOSUID | MNT_LOCK_NOEXEC);
+
                /* Verify the mount flags are equal to or more permissive
                 * than the proposed new mount.
                 */
-               if ((mnt->mnt.mnt_flags & MNT_LOCK_READONLY) &&
+               if ((mnt_flags & MNT_LOCK_READONLY) &&
                    !(new_flags & MNT_READONLY))
                        continue;
-               if ((mnt->mnt.mnt_flags & MNT_LOCK_NODEV) &&
+               if ((mnt_flags & MNT_LOCK_NODEV) &&
                    !(new_flags & MNT_NODEV))
                        continue;
-               if ((mnt->mnt.mnt_flags & MNT_LOCK_ATIME) &&
-                   ((mnt->mnt.mnt_flags & MNT_ATIME_MASK) != (new_flags & MNT_ATIME_MASK)))
+               if ((mnt_flags & MNT_LOCK_NOSUID) &&
+                   !(new_flags & MNT_NOSUID))
+                       continue;
+               if ((mnt_flags & MNT_LOCK_NOEXEC) &&
+                   !(new_flags & MNT_NOEXEC))
+                       continue;
+               if ((mnt_flags & MNT_LOCK_ATIME) &&
+                   ((mnt_flags & MNT_ATIME_MASK) != (new_flags & MNT_ATIME_MASK)))
                        continue;
 
                /* This mount is not fully visible if there are any
@@ -3240,16 +3266,18 @@ static bool fs_fully_visible(struct file_system_type *type, int *new_mnt_flags)
                list_for_each_entry(child, &mnt->mnt_mounts, mnt_child) {
                        struct inode *inode = child->mnt_mountpoint->d_inode;
                        /* Only worry about locked mounts */
-                       if (!(mnt->mnt.mnt_flags & MNT_LOCKED))
+                       if (!(mnt_flags & MNT_LOCKED))
                                continue;
                        /* Is the directory permanetly empty? */
                        if (!is_empty_dir_inode(inode))
                                goto next;
                }
                /* Preserve the locked attributes */
-               *new_mnt_flags |= mnt->mnt.mnt_flags & (MNT_LOCK_READONLY | \
-                                                       MNT_LOCK_NODEV    | \
-                                                       MNT_LOCK_ATIME);
+               *new_mnt_flags |= mnt_flags & (MNT_LOCK_READONLY | \
+                                              MNT_LOCK_NODEV    | \
+                                              MNT_LOCK_NOSUID   | \
+                                              MNT_LOCK_NOEXEC   | \
+                                              MNT_LOCK_ATIME);
                visible = true;
                goto found;
        next:   ;