1 files changed, 206 insertions, 174 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index 61bf376e29e..7953c96a207 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",