1 files changed, 206 insertions, 174 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index 61bf376e29e8..7953c96a2071 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -25,18 +25,21 @@
 #include <linux/security.h>
 #include <linux/mount.h>
 #include <linux/ramfs.h>
+#include <linux/log2.h>
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
 #include "pnode.h"
 #include "internal.h"
 
+#define HASH_SHIFT ilog2(PAGE_SIZE / sizeof(struct list_head))
+#define HASH_SIZE (1UL << HASH_SHIFT)
+
 /* spinlock for vfsmount related operations, inplace of dcache_lock */
 __cacheline_aligned_in_smp DEFINE_SPINLOCK(vfsmount_lock);
 
 static int event;
 
 static struct list_head *mount_hashtable __read_mostly;
-static int hash_mask __read_mostly, hash_bits __read_mostly;
 static struct kmem_cache *mnt_cache __read_mostly;
 static struct rw_semaphore namespace_sem;
 
@@ -48,8 +51,8 @@ static inline unsigned long hash(struct vfsmount *mnt, struct dentry *dentry)
 {
         unsigned long tmp = ((unsigned long)mnt / L1_CACHE_BYTES);
         tmp += ((unsigned long)dentry / L1_CACHE_BYTES);
-        tmp = tmp + (tmp >> hash_bits);
-        return tmp & hash_mask;
+        tmp = tmp + (tmp >> HASH_SHIFT);
+        return tmp & (HASH_SIZE - 1);
 }
 
 struct vfsmount *alloc_vfsmnt(const char *name)
@@ -154,13 +157,13 @@ static void __touch_mnt_namespace(struct mnt_namespace *ns)
 
 static void detach_mnt(struct vfsmount *mnt, struct nameidata *old_nd)
 {
-        old_nd->dentry = mnt->mnt_mountpoint;
-        old_nd->mnt = mnt->mnt_parent;
+        old_nd->path.dentry = mnt->mnt_mountpoint;
+        old_nd->path.mnt = mnt->mnt_parent;
         mnt->mnt_parent = mnt;
         mnt->mnt_mountpoint = mnt->mnt_root;
         list_del_init(&mnt->mnt_child);
         list_del_init(&mnt->mnt_hash);
-        old_nd->dentry->d_mounted--;
+        old_nd->path.dentry->d_mounted--;
 }
 
 void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry,
@@ -173,10 +176,10 @@ void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry,
 
 static void attach_mnt(struct vfsmount *mnt, struct nameidata *nd)
 {
-        mnt_set_mountpoint(nd->mnt, nd->dentry, mnt);
+        mnt_set_mountpoint(nd->path.mnt, nd->path.dentry, mnt);
         list_add_tail(&mnt->mnt_hash, mount_hashtable +
-                        hash(nd->mnt, nd->dentry));
-        list_add_tail(&mnt->mnt_child, &nd->mnt->mnt_mounts);
+                        hash(nd->path.mnt, nd->path.dentry));
+        list_add_tail(&mnt->mnt_child, &nd->path.mnt->mnt_mounts);
 }
 
 /*
@@ -317,6 +320,50 @@ void mnt_unpin(struct vfsmount *mnt)
 
 EXPORT_SYMBOL(mnt_unpin);
 
+static inline void mangle(struct seq_file *m, const char *s)
+{
+        seq_escape(m, s, " \t\n\\");
+}
+
+/*
+ * Simple .show_options callback for filesystems which don't want to
+ * implement more complex mount option showing.
+ *
+ * See also save_mount_options().
+ */
+int generic_show_options(struct seq_file *m, struct vfsmount *mnt)
+{
+        const char *options = mnt->mnt_sb->s_options;
+
+        if (options != NULL && options[0]) {
+                seq_putc(m, ',');
+                mangle(m, options);
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL(generic_show_options);
+
+/*
+ * If filesystem uses generic_show_options(), this function should be
+ * called from the fill_super() callback.
+ *
+ * The .remount_fs callback usually needs to be handled in a special
+ * way, to make sure, that previous options are not overwritten if the
+ * remount fails.
+ *
+ * Also note, that if the filesystem's .remount_fs function doesn't
+ * reset all options to their default value, but changes only newly
+ * given options, then the displayed options will not reflect reality
+ * any more.
+ */
+void save_mount_options(struct super_block *sb, char *options)
+{
+        kfree(sb->s_options);
+        sb->s_options = kstrdup(options, GFP_KERNEL);
+}
+EXPORT_SYMBOL(save_mount_options);
+
 /* iterator */
 static void *m_start(struct seq_file *m, loff_t *pos)
 {
@@ -338,11 +385,6 @@ static void m_stop(struct seq_file *m, void *v)
         up_read(&namespace_sem);
 }
 
-static inline void mangle(struct seq_file *m, const char *s)
-{
-        seq_escape(m, s, " \t\n\\");
-}
-
 static int show_vfsmnt(struct seq_file *m, void *v)
 {
         struct vfsmount *mnt = list_entry(v, struct vfsmount, mnt_list);
@@ -366,10 +408,11 @@ static int show_vfsmnt(struct seq_file *m, void *v)
                 { 0, NULL }
         };
         struct proc_fs_info *fs_infop;
+        struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
 
         mangle(m, mnt->mnt_devname ? mnt->mnt_devname : "none");
         seq_putc(m, ' ');
-        seq_path(m, mnt, mnt->mnt_root, " \t\n\\");
+        seq_path(m, &mnt_path, " \t\n\\");
         seq_putc(m, ' ');
         mangle(m, mnt->mnt_sb->s_type->name);
         if (mnt->mnt_sb->s_subtype && mnt->mnt_sb->s_subtype[0]) {
@@ -401,6 +444,7 @@ struct seq_operations mounts_op = {
 static int show_vfsstat(struct seq_file *m, void *v)
 {
         struct vfsmount *mnt = list_entry(v, struct vfsmount, mnt_list);
+        struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
         int err = 0;
 
         /* device */
@@ -412,7 +456,7 @@ static int show_vfsstat(struct seq_file *m, void *v)
 
         /* mount point */
         seq_puts(m, " mounted on ");
-        seq_path(m, mnt, mnt->mnt_root, " \t\n\\");
+        seq_path(m, &mnt_path, " \t\n\\");
         seq_putc(m, ' ');
 
         /* file system type */
@@ -551,7 +595,7 @@ static int do_umount(struct vfsmount *mnt, int flags)
          *  (2) the usage count == 1 [parent vfsmount] + 1 [sys_umount]
          */
         if (flags & MNT_EXPIRE) {
-                if (mnt == current->fs->rootmnt ||
+                if (mnt == current->fs->root.mnt ||
                     flags & (MNT_FORCE | MNT_DETACH))
                         return -EINVAL;
 
@@ -586,7 +630,7 @@ static int do_umount(struct vfsmount *mnt, int flags)
          * /reboot - static binary that would close all descriptors and
          * call reboot(9). Then init(8) could umount root and exec /reboot.
          */
-        if (mnt == current->fs->rootmnt && !(flags & MNT_DETACH)) {
+        if (mnt == current->fs->root.mnt && !(flags & MNT_DETACH)) {
                 /*
                  * Special case for "unmounting" root ...
                  * we just try to remount it readonly.
@@ -637,18 +681,20 @@ asmlinkage long sys_umount(char __user * name, int flags)
         if (retval)
                 goto out;
         retval = -EINVAL;
-        if (nd.dentry != nd.mnt->mnt_root)
+        if (nd.path.dentry != nd.path.mnt->mnt_root)
                 goto dput_and_out;
-        if (!check_mnt(nd.mnt))
+        if (!check_mnt(nd.path.mnt))
                 goto dput_and_out;
 
         retval = -EPERM;
         if (!capable(CAP_SYS_ADMIN))
                 goto dput_and_out;
 
-        retval = do_umount(nd.mnt, flags);
+        retval = do_umount(nd.path.mnt, flags);
 dput_and_out:
-        path_release_on_umount(&nd);
+        /* we mustn't call path_put() as that would clear mnt_expiry_mark */
+        dput(nd.path.dentry);
+        mntput_no_expire(nd.path.mnt);
 out:
         return retval;
 }
@@ -671,10 +717,10 @@ static int mount_is_safe(struct nameidata *nd)
                 return 0;
         return -EPERM;
 #ifdef notyet
-        if (S_ISLNK(nd->dentry->d_inode->i_mode))
+        if (S_ISLNK(nd->path.dentry->d_inode->i_mode))
                 return -EPERM;
-        if (nd->dentry->d_inode->i_mode & S_ISVTX) {
-                if (current->uid != nd->dentry->d_inode->i_uid)
+        if (nd->path.dentry->d_inode->i_mode & S_ISVTX) {
+                if (current->uid != nd->path.dentry->d_inode->i_uid)
                         return -EPERM;
         }
         if (vfs_permission(nd, MAY_WRITE))
@@ -723,8 +769,8 @@ struct vfsmount *copy_tree(struct vfsmount *mnt, struct dentry *dentry,
                                 q = q->mnt_parent;
                         }
                         p = s;
-                        nd.mnt = q;
-                        nd.dentry = p->mnt_mountpoint;
+                        nd.path.mnt = q;
+                        nd.path.dentry = p->mnt_mountpoint;
                         q = clone_mnt(p, p->mnt_root, flag);
                         if (!q)
                                 goto Enomem;
@@ -833,8 +879,8 @@ static int attach_recursive_mnt(struct vfsmount *source_mnt,
                         struct nameidata *nd, struct nameidata *parent_nd)
 {
         LIST_HEAD(tree_list);
-        struct vfsmount *dest_mnt = nd->mnt;
-        struct dentry *dest_dentry = nd->dentry;
+        struct vfsmount *dest_mnt = nd->path.mnt;
+        struct dentry *dest_dentry = nd->path.dentry;
         struct vfsmount *child, *p;
 
         if (propagate_mnt(dest_mnt, dest_dentry, source_mnt, &tree_list))
@@ -869,13 +915,13 @@ static int graft_tree(struct vfsmount *mnt, struct nameidata *nd)
         if (mnt->mnt_sb->s_flags & MS_NOUSER)
                 return -EINVAL;
 
-        if (S_ISDIR(nd->dentry->d_inode->i_mode) !=
+        if (S_ISDIR(nd->path.dentry->d_inode->i_mode) !=
               S_ISDIR(mnt->mnt_root->d_inode->i_mode))
                 return -ENOTDIR;
 
         err = -ENOENT;
-        mutex_lock(&nd->dentry->d_inode->i_mutex);
-        if (IS_DEADDIR(nd->dentry->d_inode))
+        mutex_lock(&nd->path.dentry->d_inode->i_mutex);
+        if (IS_DEADDIR(nd->path.dentry->d_inode))
                 goto out_unlock;
 
         err = security_sb_check_sb(mnt, nd);
@@ -883,10 +929,10 @@ static int graft_tree(struct vfsmount *mnt, struct nameidata *nd)
                 goto out_unlock;
 
         err = -ENOENT;
-        if (IS_ROOT(nd->dentry) || !d_unhashed(nd->dentry))
+        if (IS_ROOT(nd->path.dentry) || !d_unhashed(nd->path.dentry))
                 err = attach_recursive_mnt(mnt, nd, NULL);
 out_unlock:
-        mutex_unlock(&nd->dentry->d_inode->i_mutex);
+        mutex_unlock(&nd->path.dentry->d_inode->i_mutex);
         if (!err)
                 security_sb_post_addmount(mnt, nd);
         return err;
@@ -894,17 +940,18 @@ out_unlock:
 
 /*
  * recursively change the type of the mountpoint.
+ * noinline this do_mount helper to save do_mount stack space.
  */
-static int do_change_type(struct nameidata *nd, int flag)
+static noinline int do_change_type(struct nameidata *nd, int flag)
 {
-        struct vfsmount *m, *mnt = nd->mnt;
+        struct vfsmount *m, *mnt = nd->path.mnt;
         int recurse = flag & MS_REC;
         int type = flag & ~MS_REC;
 
         if (!capable(CAP_SYS_ADMIN))
                 return -EPERM;
 
-        if (nd->dentry != nd->mnt->mnt_root)
+        if (nd->path.dentry != nd->path.mnt->mnt_root)
                 return -EINVAL;
 
         down_write(&namespace_sem);
@@ -918,8 +965,10 @@ static int do_change_type(struct nameidata *nd, int flag)
 
 /*
  * do loopback mount.
+ * noinline this do_mount helper to save do_mount stack space.
  */
-static int do_loopback(struct nameidata *nd, char *old_name, int recurse)
+static noinline int do_loopback(struct nameidata *nd, char *old_name,
+                                int recurse)
 {
         struct nameidata old_nd;
         struct vfsmount *mnt = NULL;
@@ -934,17 +983,17 @@ static int do_loopback(struct nameidata *nd, char *old_name, int recurse)
 
         down_write(&namespace_sem);
         err = -EINVAL;
-        if (IS_MNT_UNBINDABLE(old_nd.mnt))
-                goto out;
+        if (IS_MNT_UNBINDABLE(old_nd.path.mnt))
+                goto out;
 
-        if (!check_mnt(nd->mnt) || !check_mnt(old_nd.mnt))
+        if (!check_mnt(nd->path.mnt) || !check_mnt(old_nd.path.mnt))
                 goto out;
 
         err = -ENOMEM;
         if (recurse)
-                mnt = copy_tree(old_nd.mnt, old_nd.dentry, 0);
+                mnt = copy_tree(old_nd.path.mnt, old_nd.path.dentry, 0);
         else
-                mnt = clone_mnt(old_nd.mnt, old_nd.dentry, 0);
+                mnt = clone_mnt(old_nd.path.mnt, old_nd.path.dentry, 0);
 
         if (!mnt)
                 goto out;
@@ -960,7 +1009,7 @@ static int do_loopback(struct nameidata *nd, char *old_name, int recurse)
 
 out:
         up_write(&namespace_sem);
-        path_release(&old_nd);
+        path_put(&old_nd.path);
         return err;
 }
 
@@ -968,29 +1017,30 @@ out:
  * change filesystem flags. dir should be a physical root of filesystem.
  * If you've mounted a non-root directory somewhere and want to do remount
  * on it - tough luck.
+ * noinline this do_mount helper to save do_mount stack space.
  */
-static int do_remount(struct nameidata *nd, int flags, int mnt_flags,
+static noinline int do_remount(struct nameidata *nd, int flags, int mnt_flags,
                       void *data)
 {
         int err;
-        struct super_block *sb = nd->mnt->mnt_sb;
+        struct super_block *sb = nd->path.mnt->mnt_sb;
 
         if (!capable(CAP_SYS_ADMIN))
                 return -EPERM;
 
-        if (!check_mnt(nd->mnt))
+        if (!check_mnt(nd->path.mnt))
                 return -EINVAL;
 
-        if (nd->dentry != nd->mnt->mnt_root)
+        if (nd->path.dentry != nd->path.mnt->mnt_root)
                 return -EINVAL;
 
         down_write(&sb->s_umount);
         err = do_remount_sb(sb, flags, data, 0);
         if (!err)
-                nd->mnt->mnt_flags = mnt_flags;
+                nd->path.mnt->mnt_flags = mnt_flags;
         up_write(&sb->s_umount);
         if (!err)
-                security_sb_post_remount(nd->mnt, flags, data);
+                security_sb_post_remount(nd->path.mnt, flags, data);
         return err;
 }
 
@@ -1004,7 +1054,10 @@ static inline int tree_contains_unbindable(struct vfsmount *mnt)
         return 0;
 }
 
-static int do_move_mount(struct nameidata *nd, char *old_name)
+/*
+ * noinline this do_mount helper to save do_mount stack space.
+ */
+static noinline int do_move_mount(struct nameidata *nd, char *old_name)
 {
         struct nameidata old_nd, parent_nd;
         struct vfsmount *p;
@@ -1018,69 +1071,74 @@ static int do_move_mount(struct nameidata *nd, char *old_name)
                 return err;
 
         down_write(&namespace_sem);
-        while (d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
+        while (d_mountpoint(nd->path.dentry) &&
+               follow_down(&nd->path.mnt, &nd->path.dentry))
                 ;
         err = -EINVAL;
-        if (!check_mnt(nd->mnt) || !check_mnt(old_nd.mnt))
+        if (!check_mnt(nd->path.mnt) || !check_mnt(old_nd.path.mnt))
                 goto out;
 
         err = -ENOENT;
-        mutex_lock(&nd->dentry->d_inode->i_mutex);
-        if (IS_DEADDIR(nd->dentry->d_inode))
+        mutex_lock(&nd->path.dentry->d_inode->i_mutex);
+        if (IS_DEADDIR(nd->path.dentry->d_inode))
                 goto out1;
 
-        if (!IS_ROOT(nd->dentry) && d_unhashed(nd->dentry))
+        if (!IS_ROOT(nd->path.dentry) && d_unhashed(nd->path.dentry))
                 goto out1;
 
         err = -EINVAL;
-        if (old_nd.dentry != old_nd.mnt->mnt_root)
+        if (old_nd.path.dentry != old_nd.path.mnt->mnt_root)
                 goto out1;
 
-        if (old_nd.mnt == old_nd.mnt->mnt_parent)
+        if (old_nd.path.mnt == old_nd.path.mnt->mnt_parent)
                 goto out1;
 
-        if (S_ISDIR(nd->dentry->d_inode->i_mode) !=
-              S_ISDIR(old_nd.dentry->d_inode->i_mode))
+        if (S_ISDIR(nd->path.dentry->d_inode->i_mode) !=
+              S_ISDIR(old_nd.path.dentry->d_inode->i_mode))
                 goto out1;
         /*
          * Don't move a mount residing in a shared parent.
          */
-        if (old_nd.mnt->mnt_parent && IS_MNT_SHARED(old_nd.mnt->mnt_parent))
+        if (old_nd.path.mnt->mnt_parent &&
+            IS_MNT_SHARED(old_nd.path.mnt->mnt_parent))
                 goto out1;
         /*
          * Don't move a mount tree containing unbindable mounts to a destination
          * mount which is shared.
          */
-        if (IS_MNT_SHARED(nd->mnt) && tree_contains_unbindable(old_nd.mnt))
+        if (IS_MNT_SHARED(nd->path.mnt) &&
+            tree_contains_unbindable(old_nd.path.mnt))
                 goto out1;
         err = -ELOOP;
-        for (p = nd->mnt; p->mnt_parent != p; p = p->mnt_parent)
-                if (p == old_nd.mnt)
+        for (p = nd->path.mnt; p->mnt_parent != p; p = p->mnt_parent)
+                if (p == old_nd.path.mnt)
                         goto out1;
 
-        if ((err = attach_recursive_mnt(old_nd.mnt, nd, &parent_nd)))
+        err = attach_recursive_mnt(old_nd.path.mnt, nd, &parent_nd);
+        if (err)
                 goto out1;
 
         spin_lock(&vfsmount_lock);
         /* if the mount is moved, it should no longer be expire
          * automatically */
-        list_del_init(&old_nd.mnt->mnt_expire);
+        list_del_init(&old_nd.path.mnt->mnt_expire);
         spin_unlock(&vfsmount_lock);
 out1:
-        mutex_unlock(&nd->dentry->d_inode->i_mutex);
+        mutex_unlock(&nd->path.dentry->d_inode->i_mutex);
 out:
         up_write(&namespace_sem);
         if (!err)
-                path_release(&parent_nd);
-        path_release(&old_nd);
+                path_put(&parent_nd.path);
+        path_put(&old_nd.path);
         return err;
 }
 
 /*
  * create a new mount for userspace and request it to be added into the
  * namespace's tree
+ * noinline this do_mount helper to save do_mount stack space.
  */
-static int do_new_mount(struct nameidata *nd, char *type, int flags,
+static noinline int do_new_mount(struct nameidata *nd, char *type, int flags,
                         int mnt_flags, char *name, void *data)
 {
         struct vfsmount *mnt;
@@ -1110,16 +1168,17 @@ int do_add_mount(struct vfsmount *newmnt, struct nameidata *nd,
 
         down_write(&namespace_sem);
         /* Something was mounted here while we slept */
-        while (d_mountpoint(nd->dentry) && follow_down(&nd->mnt, &nd->dentry))
+        while (d_mountpoint(nd->path.dentry) &&
+               follow_down(&nd->path.mnt, &nd->path.dentry))
                 ;
         err = -EINVAL;
-        if (!check_mnt(nd->mnt))
+        if (!check_mnt(nd->path.mnt))
                 goto unlock;
 
         /* Refuse the same filesystem on the same mount point */
         err = -EBUSY;
-        if (nd->mnt->mnt_sb == newmnt->mnt_sb &&
-            nd->mnt->mnt_root == nd->dentry)
+        if (nd->path.mnt->mnt_sb == newmnt->mnt_sb &&
+            nd->path.mnt->mnt_root == nd->path.dentry)
                 goto unlock;
 
         err = -EINVAL;
@@ -1455,7 +1514,7 @@ long do_mount(char *dev_name, char *dir_name, char *type_page,
                 retval = do_new_mount(&nd, type_page, flags, mnt_flags,
                                       dev_name, data_page);
 dput_out:
-        path_release(&nd);
+        path_put(&nd.path);
         return retval;
 }
 
@@ -1502,17 +1561,17 @@ static struct mnt_namespace *dup_mnt_ns(struct mnt_namespace *mnt_ns,
         while (p) {
                 q->mnt_ns = new_ns;
                 if (fs) {
-                        if (p == fs->rootmnt) {
+                        if (p == fs->root.mnt) {
                                 rootmnt = p;
-                                fs->rootmnt = mntget(q);
+                                fs->root.mnt = mntget(q);
                         }
-                        if (p == fs->pwdmnt) {
+                        if (p == fs->pwd.mnt) {
                                 pwdmnt = p;
-                                fs->pwdmnt = mntget(q);
+                                fs->pwd.mnt = mntget(q);
                         }
-                        if (p == fs->altrootmnt) {
+                        if (p == fs->altroot.mnt) {
                                 altrootmnt = p;
-                                fs->altrootmnt = mntget(q);
+                                fs->altroot.mnt = mntget(q);
                         }
                 }
                 p = next_mnt(p, mnt_ns->root);
@@ -1593,44 +1652,35 @@ out1:
  * Replace the fs->{rootmnt,root} with {mnt,dentry}. Put the old values.
  * It can block. Requires the big lock held.
  */
-void set_fs_root(struct fs_struct *fs, struct vfsmount *mnt,
-                 struct dentry *dentry)
+void set_fs_root(struct fs_struct *fs, struct path *path)
 {
-        struct dentry *old_root;
-        struct vfsmount *old_rootmnt;
+        struct path old_root;
+
         write_lock(&fs->lock);
         old_root = fs->root;
-        old_rootmnt = fs->rootmnt;
-        fs->rootmnt = mntget(mnt);
-        fs->root = dget(dentry);
+        fs->root = *path;
+        path_get(path);
         write_unlock(&fs->lock);
-        if (old_root) {
-                dput(old_root);
-                mntput(old_rootmnt);
-        }
+        if (old_root.dentry)
+                path_put(&old_root);
 }
 
 /*
  * Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values.
  * It can block. Requires the big lock held.
  */
-void set_fs_pwd(struct fs_struct *fs, struct vfsmount *mnt,
-                struct dentry *dentry)
+void set_fs_pwd(struct fs_struct *fs, struct path *path)
 {
-        struct dentry *old_pwd;
-        struct vfsmount *old_pwdmnt;
+        struct path old_pwd;
 
         write_lock(&fs->lock);
         old_pwd = fs->pwd;
-        old_pwdmnt = fs->pwdmnt;
-        fs->pwdmnt = mntget(mnt);
-        fs->pwd = dget(dentry);
+        fs->pwd = *path;
+        path_get(path);
         write_unlock(&fs->lock);
 
-        if (old_pwd) {
-                dput(old_pwd);
-                mntput(old_pwdmnt);
-        }
+        if (old_pwd.dentry)
+                path_put(&old_pwd);
 }
 
 static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd)
@@ -1645,12 +1695,12 @@ static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd)
                 if (fs) {
                         atomic_inc(&fs->count);
                         task_unlock(p);
-                        if (fs->root == old_nd->dentry
-                            && fs->rootmnt == old_nd->mnt)
-                                set_fs_root(fs, new_nd->mnt, new_nd->dentry);
-                        if (fs->pwd == old_nd->dentry
-                            && fs->pwdmnt == old_nd->mnt)
-                                set_fs_pwd(fs, new_nd->mnt, new_nd->dentry);
+                        if (fs->root.dentry == old_nd->path.dentry
+                            && fs->root.mnt == old_nd->path.mnt)
+                                set_fs_root(fs, &new_nd->path);
+                        if (fs->pwd.dentry == old_nd->path.dentry
+                            && fs->pwd.mnt == old_nd->path.mnt)
+                                set_fs_pwd(fs, &new_nd->path);
                         put_fs_struct(fs);
                 } else
                         task_unlock(p);
@@ -1700,7 +1750,7 @@ asmlinkage long sys_pivot_root(const char __user * new_root,
         if (error)
                 goto out0;
         error = -EINVAL;
-        if (!check_mnt(new_nd.mnt))
+        if (!check_mnt(new_nd.path.mnt))
                 goto out1;
 
         error = __user_walk(put_old, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &old_nd);
@@ -1709,74 +1759,78 @@ asmlinkage long sys_pivot_root(const char __user * new_root,
 
         error = security_sb_pivotroot(&old_nd, &new_nd);
         if (error) {
-                path_release(&old_nd);
+                path_put(&old_nd.path);
                 goto out1;
         }
 
         read_lock(&current->fs->lock);
-        user_nd.mnt = mntget(current->fs->rootmnt);
-        user_nd.dentry = dget(current->fs->root);
+        user_nd.path = current->fs->root;
+        path_get(&current->fs->root);
         read_unlock(&current->fs->lock);
         down_write(&namespace_sem);
-        mutex_lock(&old_nd.dentry->d_inode->i_mutex);
+        mutex_lock(&old_nd.path.dentry->d_inode->i_mutex);
         error = -EINVAL;
-        if (IS_MNT_SHARED(old_nd.mnt) ||
-                IS_MNT_SHARED(new_nd.mnt->mnt_parent) ||
-                IS_MNT_SHARED(user_nd.mnt->mnt_parent))
+        if (IS_MNT_SHARED(old_nd.path.mnt) ||
+                IS_MNT_SHARED(new_nd.path.mnt->mnt_parent) ||
+                IS_MNT_SHARED(user_nd.path.mnt->mnt_parent))
                 goto out2;
-        if (!check_mnt(user_nd.mnt))
+        if (!check_mnt(user_nd.path.mnt))
                 goto out2;
         error = -ENOENT;
-        if (IS_DEADDIR(new_nd.dentry->d_inode))
+        if (IS_DEADDIR(new_nd.path.dentry->d_inode))
                 goto out2;
-        if (d_unhashed(new_nd.dentry) && !IS_ROOT(new_nd.dentry))
+        if (d_unhashed(new_nd.path.dentry) && !IS_ROOT(new_nd.path.dentry))
                 goto out2;
-        if (d_unhashed(old_nd.dentry) && !IS_ROOT(old_nd.dentry))
+        if (d_unhashed(old_nd.path.dentry) && !IS_ROOT(old_nd.path.dentry))
                 goto out2;
         error = -EBUSY;
-        if (new_nd.mnt == user_nd.mnt || old_nd.mnt == user_nd.mnt)
+        if (new_nd.path.mnt == user_nd.path.mnt ||
+            old_nd.path.mnt == user_nd.path.mnt)
                 goto out2; /* loop, on the same file system  */
         error = -EINVAL;
-        if (user_nd.mnt->mnt_root != user_nd.dentry)
+        if (user_nd.path.mnt->mnt_root != user_nd.path.dentry)
                 goto out2; /* not a mountpoint */
-        if (user_nd.mnt->mnt_parent == user_nd.mnt)
+        if (user_nd.path.mnt->mnt_parent == user_nd.path.mnt)
                 goto out2; /* not attached */
-        if (new_nd.mnt->mnt_root != new_nd.dentry)
+        if (new_nd.path.mnt->mnt_root != new_nd.path.dentry)
                 goto out2; /* not a mountpoint */
-        if (new_nd.mnt->mnt_parent == new_nd.mnt)
+        if (new_nd.path.mnt->mnt_parent == new_nd.path.mnt)
                 goto out2; /* not attached */
-        tmp = old_nd.mnt; /* make sure we can reach put_old from new_root */
+        /* make sure we can reach put_old from new_root */
+        tmp = old_nd.path.mnt;
         spin_lock(&vfsmount_lock);
-        if (tmp != new_nd.mnt) {
+        if (tmp != new_nd.path.mnt) {
                 for (;;) {
                         if (tmp->mnt_parent == tmp)
                                 goto out3; /* already mounted on put_old */
-                        if (tmp->mnt_parent == new_nd.mnt)
+                        if (tmp->mnt_parent == new_nd.path.mnt)
                                 break;
                         tmp = tmp->mnt_parent;
                 }
-                if (!is_subdir(tmp->mnt_mountpoint, new_nd.dentry))
+                if (!is_subdir(tmp->mnt_mountpoint, new_nd.path.dentry))
                         goto out3;
-        } else if (!is_subdir(old_nd.dentry, new_nd.dentry))
+        } else if (!is_subdir(old_nd.path.dentry, new_nd.path.dentry))
                 goto out3;
-        detach_mnt(new_nd.mnt, &parent_nd);
-        detach_mnt(user_nd.mnt, &root_parent);
-        attach_mnt(user_nd.mnt, &old_nd);     /* mount old root on put_old */
-        attach_mnt(new_nd.mnt, &root_parent); /* mount new_root on / */
+        detach_mnt(new_nd.path.mnt, &parent_nd);
+        detach_mnt(user_nd.path.mnt, &root_parent);
+        /* mount old root on put_old */
+        attach_mnt(user_nd.path.mnt, &old_nd);
+        /* mount new_root on / */
+        attach_mnt(new_nd.path.mnt, &root_parent);
         touch_mnt_namespace(current->nsproxy->mnt_ns);
         spin_unlock(&vfsmount_lock);
         chroot_fs_refs(&user_nd, &new_nd);
         security_sb_post_pivotroot(&user_nd, &new_nd);
         error = 0;
-        path_release(&root_parent);
-        path_release(&parent_nd);
+        path_put(&root_parent.path);
+        path_put(&parent_nd.path);
 out2:
-        mutex_unlock(&old_nd.dentry->d_inode->i_mutex);
+        mutex_unlock(&old_nd.path.dentry->d_inode->i_mutex);
         up_write(&namespace_sem);
-        path_release(&user_nd);
-        path_release(&old_nd);
+        path_put(&user_nd.path);
+        path_put(&old_nd.path);
 out1:
-        path_release(&new_nd);
+        path_put(&new_nd.path);
 out0:
         unlock_kernel();
         return error;
@@ -1789,6 +1843,7 @@ static void __init init_mount_tree(void)
 {
         struct vfsmount *mnt;
         struct mnt_namespace *ns;
+        struct path root;
 
         mnt = do_kern_mount("rootfs", 0, "rootfs", NULL);
         if (IS_ERR(mnt))
@@ -1807,15 +1862,16 @@ static void __init init_mount_tree(void)
         init_task.nsproxy->mnt_ns = ns;
         get_mnt_ns(ns);
 
-        set_fs_pwd(current->fs, ns->root, ns->root->mnt_root);
-        set_fs_root(current->fs, ns->root, ns->root->mnt_root);
+        root.mnt = ns->root;
+        root.dentry = ns->root->mnt_root;
+
+        set_fs_pwd(current->fs, &root);
+        set_fs_root(current->fs, &root);
 }
 
 void __init mnt_init(void)
 {
-        struct list_head *d;
-        unsigned int nr_hash;
-        int i;
+        unsigned u;
         int err;
 
         init_rwsem(&namespace_sem);
@@ -1828,35 +1884,11 @@ void __init mnt_init(void)
         if (!mount_hashtable)
                 panic("Failed to allocate mount hash table\n");
 
-        /*
-         * Find the power-of-two list-heads that can fit into the allocation..
-         * We don't guarantee that "sizeof(struct list_head)" is necessarily
-         * a power-of-two.
-         */
-        nr_hash = PAGE_SIZE / sizeof(struct list_head);
-        hash_bits = 0;
-        do {
-                hash_bits++;
-        } while ((nr_hash >> hash_bits) != 0);
-        hash_bits--;
+        printk("Mount-cache hash table entries: %lu\n", HASH_SIZE);
+
+        for (u = 0; u < HASH_SIZE; u++)
+                INIT_LIST_HEAD(&mount_hashtable[u]);
 
-        /*
-         * Re-calculate the actual number of entries and the mask
-         * from the number of bits we can fit.
-         */
-        nr_hash = 1UL << hash_bits;
-        hash_mask = nr_hash - 1;
-
-        printk("Mount-cache hash table entries: %d\n", nr_hash);
-
-        /* And initialize the newly allocated array */
-        d = mount_hashtable;
-        i = nr_hash;
-        do {
-                INIT_LIST_HEAD(d);
-                d++;
-                i--;
-        } while (i);
         err = sysfs_init();
         if (err)
                 printk(KERN_WARNING "%s: sysfs_init error: %d\n",