1 files changed, 617 insertions, 407 deletions

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index e026c807e6b..1e2872b2534 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -1,11 +1,13 @@
 /*
  * hugetlbpage-backed filesystem.  Based on ramfs.
  *
- * William Irwin, 2002
+ * Nadia Yvette Chambers, 2002
  *
  * Copyright (C) 2002 Linus Torvalds.
  */
 
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <linux/module.h>
 #include <linux/thread_info.h>
 #include <asm/current.h>
@@ -13,38 +15,78 @@
 #include <linux/fs.h>
 #include <linux/mount.h>
 #include <linux/file.h>
+#include <linux/kernel.h>
 #include <linux/writeback.h>
 #include <linux/pagemap.h>
 #include <linux/highmem.h>
 #include <linux/init.h>
 #include <linux/string.h>
+#include <linux/capability.h>
+#include <linux/ctype.h>
 #include <linux/backing-dev.h>
 #include <linux/hugetlb.h>
 #include <linux/pagevec.h>
-#include <linux/quotaops.h>
+#include <linux/parser.h>
+#include <linux/mman.h>
 #include <linux/slab.h>
 #include <linux/dnotify.h>
 #include <linux/statfs.h>
 #include <linux/security.h>
+#include <linux/magic.h>
+#include <linux/migrate.h>
 
 #include <asm/uaccess.h>
 
-/* some random number */
-#define HUGETLBFS_MAGIC	0x958458f6
+static const struct super_operations hugetlbfs_ops;
+static const struct address_space_operations hugetlbfs_aops;
+const struct file_operations hugetlbfs_file_operations;
+static const struct inode_operations hugetlbfs_dir_inode_operations;
+static const struct inode_operations hugetlbfs_inode_operations;
+
+struct hugetlbfs_config {
+	kuid_t   uid;
+	kgid_t   gid;
+	umode_t mode;
+	long	nr_blocks;
+	long	nr_inodes;
+	struct hstate *hstate;
+};
+
+struct hugetlbfs_inode_info {
+	struct shared_policy policy;
+	struct inode vfs_inode;
+};
 
-static struct super_operations hugetlbfs_ops;
-static struct address_space_operations hugetlbfs_aops;
-struct file_operations hugetlbfs_file_operations;
-static struct inode_operations hugetlbfs_dir_inode_operations;
-static struct inode_operations hugetlbfs_inode_operations;
+static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
+{
+	return container_of(inode, struct hugetlbfs_inode_info, vfs_inode);
+}
 
 static struct backing_dev_info hugetlbfs_backing_dev_info = {
+	.name		= "hugetlbfs",
 	.ra_pages	= 0,	/* No readahead */
-	.capabilities	= BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
+	.capabilities	= BDI_CAP_NO_ACCT_AND_WRITEBACK,
 };
 
 int sysctl_hugetlb_shm_group;
 
+enum {
+	Opt_size, Opt_nr_inodes,
+	Opt_mode, Opt_uid, Opt_gid,
+	Opt_pagesize,
+	Opt_err,
+};
+
+static const match_table_t tokens = {
+	{Opt_size,	"size=%s"},
+	{Opt_nr_inodes,	"nr_inodes=%s"},
+	{Opt_mode,	"mode=%o"},
+	{Opt_uid,	"uid=%u"},
+	{Opt_gid,	"gid=%u"},
+	{Opt_pagesize,	"pagesize=%s"},
+	{Opt_err,	NULL},
+};
+
 static void huge_pagevec_release(struct pagevec *pvec)
 {
 	int i;
@@ -55,88 +97,47 @@ static void huge_pagevec_release(struct pagevec *pvec)
 	pagevec_reinit(pvec);
 }
 
-/*
- * huge_pages_needed tries to determine the number of new huge pages that
- * will be required to fully populate this VMA.  This will be equal to
- * the size of the VMA in huge pages minus the number of huge pages
- * (covered by this VMA) that are found in the page cache.
- *
- * Result is in bytes to be compatible with is_hugepage_mem_enough()
- */
-unsigned long
-huge_pages_needed(struct address_space *mapping, struct vm_area_struct *vma)
-{
-	int i;
-	struct pagevec pvec;
-	unsigned long start = vma->vm_start;
-	unsigned long end = vma->vm_end;
-	unsigned long hugepages = (end - start) >> HPAGE_SHIFT;
-	pgoff_t next = vma->vm_pgoff;
-	pgoff_t endpg = next + ((end - start) >> PAGE_SHIFT);
-
-	pagevec_init(&pvec, 0);
-	while (next < endpg) {
-		if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE))
-			break;
-		for (i = 0; i < pagevec_count(&pvec); i++) {
-			struct page *page = pvec.pages[i];
-			if (page->index > next)
-				next = page->index;
-			if (page->index >= endpg)
-				break;
-			next++;
-			hugepages--;
-		}
-		huge_pagevec_release(&pvec);
-	}
-	return hugepages << HPAGE_SHIFT;
-}
-
 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 {
-	struct inode *inode = file->f_dentry->d_inode;
-	struct address_space *mapping = inode->i_mapping;
-	unsigned long bytes;
+	struct inode *inode = file_inode(file);
 	loff_t len, vma_len;
 	int ret;
+	struct hstate *h = hstate_file(file);
+
+	/*
+	 * vma address alignment (but not the pgoff alignment) has
+	 * already been checked by prepare_hugepage_range.  If you add
+	 * any error returns here, do so after setting VM_HUGETLB, so
+	 * is_vm_hugetlb_page tests below unmap_region go the right
+	 * way when do_mmap_pgoff unwinds (may be important on powerpc
+	 * and ia64).
+	 */
+	vma->vm_flags |= VM_HUGETLB | VM_DONTEXPAND;
+	vma->vm_ops = &hugetlb_vm_ops;
 
-	if ((vma->vm_flags & (VM_MAYSHARE | VM_WRITE)) == VM_WRITE)
-		return -EINVAL;
-
-	if (vma->vm_pgoff & (HPAGE_SIZE / PAGE_SIZE - 1))
-		return -EINVAL;
-
-	if (vma->vm_start & ~HPAGE_MASK)
-		return -EINVAL;
-
-	if (vma->vm_end & ~HPAGE_MASK)
-		return -EINVAL;
-
-	if (vma->vm_end - vma->vm_start < HPAGE_SIZE)
+	if (vma->vm_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
 		return -EINVAL;
 
-	bytes = huge_pages_needed(mapping, vma);
-	if (!is_hugepage_mem_enough(bytes))
-		return -ENOMEM;
-
 	vma_len = (loff_t)(vma->vm_end - vma->vm_start);
 
-	down(&inode->i_sem);
+	mutex_lock(&inode->i_mutex);
 	file_accessed(file);
-	vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
-	vma->vm_ops = &hugetlb_vm_ops;
 
 	ret = -ENOMEM;
 	len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
-	if (!(vma->vm_flags & VM_WRITE) && len > inode->i_size)
+
+	if (hugetlb_reserve_pages(inode,
+				vma->vm_pgoff >> huge_page_order(h),
+				len >> huge_page_shift(h), vma,
+				vma->vm_flags))
 		goto out;
 
 	ret = 0;
 	hugetlb_prefault_arch_hook(vma->vm_mm);
-	if (inode->i_size < len)
+	if (vma->vm_flags & VM_WRITE && inode->i_size < len)
 		inode->i_size = len;
 out:
-	up(&inode->i_sem);
+	mutex_unlock(&inode->i_mutex);
 
 	return ret;
 }
@@ -145,96 +146,198 @@ out:
  * Called under down_write(mmap_sem).
  */
 
-#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
-unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
-		unsigned long len, unsigned long pgoff, unsigned long flags);
-#else
+#ifndef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
 static unsigned long
 hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 		unsigned long len, unsigned long pgoff, unsigned long flags)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
-	unsigned long start_addr;
+	struct hstate *h = hstate_file(file);
+	struct vm_unmapped_area_info info;
 
-	if (len & ~HPAGE_MASK)
+	if (len & ~huge_page_mask(h))
 		return -EINVAL;
 	if (len > TASK_SIZE)
 		return -ENOMEM;
 
+	if (flags & MAP_FIXED) {
+		if (prepare_hugepage_range(file, addr, len))
+			return -EINVAL;
+		return addr;
+	}
+
 	if (addr) {
-		addr = ALIGN(addr, HPAGE_SIZE);
+		addr = ALIGN(addr, huge_page_size(h));
 		vma = find_vma(mm, addr);
 		if (TASK_SIZE - len >= addr &&
 		    (!vma || addr + len <= vma->vm_start))
 			return addr;
 	}
 
-	start_addr = mm->free_area_cache;
-
-	if (len <= mm->cached_hole_size)
-		start_addr = TASK_UNMAPPED_BASE;
-
-full_search:
-	addr = ALIGN(start_addr, HPAGE_SIZE);
+	info.flags = 0;
+	info.length = len;
+	info.low_limit = TASK_UNMAPPED_BASE;
+	info.high_limit = TASK_SIZE;
+	info.align_mask = PAGE_MASK & ~huge_page_mask(h);
+	info.align_offset = 0;
+	return vm_unmapped_area(&info);
+}
+#endif
 
-	for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
-		/* At this point:  (!vma || addr < vma->vm_end). */
-		if (TASK_SIZE - len < addr) {
-			/*
-			 * Start a new search - just in case we missed
-			 * some holes.
-			 */
-			if (start_addr != TASK_UNMAPPED_BASE) {
-				start_addr = TASK_UNMAPPED_BASE;
-				goto full_search;
-			}
-			return -ENOMEM;
+static int
+hugetlbfs_read_actor(struct page *page, unsigned long offset,
+			char __user *buf, unsigned long count,
+			unsigned long size)
+{
+	char *kaddr;
+	unsigned long left, copied = 0;
+	int i, chunksize;
+
+	if (size > count)
+		size = count;
+
+	/* Find which 4k chunk and offset with in that chunk */
+	i = offset >> PAGE_CACHE_SHIFT;
+	offset = offset & ~PAGE_CACHE_MASK;
+
+	while (size) {
+		chunksize = PAGE_CACHE_SIZE;
+		if (offset)
+			chunksize -= offset;
+		if (chunksize > size)
+			chunksize = size;
+		kaddr = kmap(&page[i]);
+		left = __copy_to_user(buf, kaddr + offset, chunksize);
+		kunmap(&page[i]);
+		if (left) {
+			copied += (chunksize - left);
+			break;
 		}
-
-		if (!vma || addr + len <= vma->vm_start)
-			return addr;
-		addr = ALIGN(vma->vm_end, HPAGE_SIZE);
+		offset = 0;
+		size -= chunksize;
+		buf += chunksize;
+		copied += chunksize;
+		i++;
 	}
+	return copied ? copied : -EFAULT;
 }
-#endif
 
 /*
- * Read a page. Again trivial. If it didn't already exist
- * in the page cache, it is zero-filled.
+ * Support for read() - Find the page attached to f_mapping and copy out the
+ * data. Its *very* similar to do_generic_mapping_read(), we can't use that
+ * since it has PAGE_CACHE_SIZE assumptions.
  */
-static int hugetlbfs_readpage(struct file *file, struct page * page)
+static ssize_t hugetlbfs_read(struct file *filp, char __user *buf,
+			      size_t len, loff_t *ppos)
 {
-	unlock_page(page);
-	return -EINVAL;
+	struct hstate *h = hstate_file(filp);
+	struct address_space *mapping = filp->f_mapping;
+	struct inode *inode = mapping->host;
+	unsigned long index = *ppos >> huge_page_shift(h);
+	unsigned long offset = *ppos & ~huge_page_mask(h);
+	unsigned long end_index;
+	loff_t isize;
+	ssize_t retval = 0;
+
+	/* validate length */
+	if (len == 0)
+		goto out;
+
+	for (;;) {
+		struct page *page;
+		unsigned long nr, ret;
+		int ra;
+
+		/* nr is the maximum number of bytes to copy from this page */
+		nr = huge_page_size(h);
+		isize = i_size_read(inode);
+		if (!isize)
+			goto out;
+		end_index = (isize - 1) >> huge_page_shift(h);
+		if (index >= end_index) {
+			if (index > end_index)
+				goto out;
+			nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
+			if (nr <= offset)
+				goto out;
+		}
+		nr = nr - offset;
+
+		/* Find the page */
+		page = find_lock_page(mapping, index);
+		if (unlikely(page == NULL)) {
+			/*
+			 * We have a HOLE, zero out the user-buffer for the
+			 * length of the hole or request.
+			 */
+			ret = len < nr ? len : nr;
+			if (clear_user(buf, ret))
+				ra = -EFAULT;
+			else
+				ra = 0;
+		} else {
+			unlock_page(page);
+
+			/*
+			 * We have the page, copy it to user space buffer.
+			 */
+			ra = hugetlbfs_read_actor(page, offset, buf, len, nr);
+			ret = ra;
+			page_cache_release(page);
+		}
+		if (ra < 0) {
+			if (retval == 0)
+				retval = ra;
+			goto out;
+		}
+
+		offset += ret;
+		retval += ret;
+		len -= ret;
+		index += offset >> huge_page_shift(h);
+		offset &= ~huge_page_mask(h);
+
+		/* short read or no more work */
+		if ((ret != nr) || (len == 0))
+			break;
+	}
+out:
+	*ppos = ((loff_t)index << huge_page_shift(h)) + offset;
+	return retval;
 }
 
-static int hugetlbfs_prepare_write(struct file *file,
-			struct page *page, unsigned offset, unsigned to)
+static int hugetlbfs_write_begin(struct file *file,
+			struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned flags,
+			struct page **pagep, void **fsdata)
 {
 	return -EINVAL;
 }
 
-static int hugetlbfs_commit_write(struct file *file,
-			struct page *page, unsigned offset, unsigned to)
+static int hugetlbfs_write_end(struct file *file, struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned copied,
+			struct page *page, void *fsdata)
 {
+	BUG();
 	return -EINVAL;
 }
 
 static void truncate_huge_page(struct page *page)
 {
-	clear_page_dirty(page);
+	cancel_dirty_page(page, /* No IO accounting for huge pages? */0);
 	ClearPageUptodate(page);
-	remove_from_page_cache(page);
-	put_page(page);
+	delete_from_page_cache(page);
 }
 
-static void truncate_hugepages(struct address_space *mapping, loff_t lstart)
+static void truncate_hugepages(struct inode *inode, loff_t lstart)
 {
-	const pgoff_t start = lstart >> HPAGE_SHIFT;
+	struct hstate *h = hstate_inode(inode);
+	struct address_space *mapping = &inode->i_data;
+	const pgoff_t start = lstart >> huge_page_shift(h);
 	struct pagevec pvec;
 	pgoff_t next;
-	int i;
+	int i, freed = 0;
 
 	pagevec_init(&pvec, 0);
 	next = start;
@@ -255,116 +358,72 @@ static void truncate_hugepages(struct address_space *mapping, loff_t lstart)
 			++next;
 			truncate_huge_page(page);
 			unlock_page(page);
-			hugetlb_put_quota(mapping);
+			freed++;
 		}
 		huge_pagevec_release(&pvec);
 	}
 	BUG_ON(!lstart && mapping->nrpages);
+	hugetlb_unreserve_pages(inode, start, freed);
 }
 
-static void hugetlbfs_delete_inode(struct inode *inode)
+static void hugetlbfs_evict_inode(struct inode *inode)
 {
-	if (inode->i_data.nrpages)
-		truncate_hugepages(&inode->i_data, 0);
-	clear_inode(inode);
-}
+	struct resv_map *resv_map;
 
-static void hugetlbfs_forget_inode(struct inode *inode)
-{
-	struct super_block *sb = inode->i_sb;
-
-	if (!hlist_unhashed(&inode->i_hash)) {
-		if (!(inode->i_state & (I_DIRTY|I_LOCK)))
-			list_move(&inode->i_list, &inode_unused);
-		inodes_stat.nr_unused++;
-		if (!sb || (sb->s_flags & MS_ACTIVE)) {
-			spin_unlock(&inode_lock);
-			return;
-		}
-		inode->i_state |= I_WILL_FREE;
-		spin_unlock(&inode_lock);
-		/*
-		 * write_inode_now is a noop as we set BDI_CAP_NO_WRITEBACK
-		 * in our backing_dev_info.
-		 */
-		write_inode_now(inode, 1);
-		spin_lock(&inode_lock);
-		inode->i_state &= ~I_WILL_FREE;
-		inodes_stat.nr_unused--;
-		hlist_del_init(&inode->i_hash);
-	}
-	list_del_init(&inode->i_list);
-	list_del_init(&inode->i_sb_list);
-	inode->i_state |= I_FREEING;
-	inodes_stat.nr_inodes--;
-	spin_unlock(&inode_lock);
-	if (inode->i_data.nrpages)
-		truncate_hugepages(&inode->i_data, 0);
+	truncate_hugepages(inode, 0);
+	resv_map = (struct resv_map *)inode->i_mapping->private_data;
+	/* root inode doesn't have the resv_map, so we should check it */
+	if (resv_map)
+		resv_map_release(&resv_map->refs);
 	clear_inode(inode);
-	destroy_inode(inode);
-}
-
-static void hugetlbfs_drop_inode(struct inode *inode)
-{
-	if (!inode->i_nlink)
-		generic_delete_inode(inode);
-	else
-		hugetlbfs_forget_inode(inode);
 }
 
-/*
- * h_pgoff is in HPAGE_SIZE units.
- * vma->vm_pgoff is in PAGE_SIZE units.
- */
 static inline void
-hugetlb_vmtruncate_list(struct prio_tree_root *root, unsigned long h_pgoff)
+hugetlb_vmtruncate_list(struct rb_root *root, pgoff_t pgoff)
 {
 	struct vm_area_struct *vma;
-	struct prio_tree_iter iter;
 
-	vma_prio_tree_foreach(vma, &iter, root, h_pgoff, ULONG_MAX) {
-		unsigned long h_vm_pgoff;
+	vma_interval_tree_foreach(vma, root, pgoff, ULONG_MAX) {
 		unsigned long v_offset;
 
-		h_vm_pgoff = vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT);
-		v_offset = (h_pgoff - h_vm_pgoff) << HPAGE_SHIFT;
 		/*
-		 * Is this VMA fully outside the truncation point?
+		 * Can the expression below overflow on 32-bit arches?
+		 * No, because the interval tree returns us only those vmas
+		 * which overlap the truncated area starting at pgoff,
+		 * and no vma on a 32-bit arch can span beyond the 4GB.
 		 */
-		if (h_vm_pgoff >= h_pgoff)
+		if (vma->vm_pgoff < pgoff)
+			v_offset = (pgoff - vma->vm_pgoff) << PAGE_SHIFT;
+		else
 			v_offset = 0;
 
-		unmap_hugepage_range(vma,
-				vma->vm_start + v_offset, vma->vm_end);
+		unmap_hugepage_range(vma, vma->vm_start + v_offset,
+				     vma->vm_end, NULL);
 	}
 }
 
-/*
- * Expanding truncates are not allowed.
- */
 static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
 {
-	unsigned long pgoff;
+	pgoff_t pgoff;
 	struct address_space *mapping = inode->i_mapping;
+	struct hstate *h = hstate_inode(inode);
 
-	if (offset > inode->i_size)
-		return -EINVAL;
-
-	BUG_ON(offset & ~HPAGE_MASK);
-	pgoff = offset >> HPAGE_SHIFT;
+	BUG_ON(offset & ~huge_page_mask(h));
+	pgoff = offset >> PAGE_SHIFT;
 
-	inode->i_size = offset;
-	spin_lock(&mapping->i_mmap_lock);
-	if (!prio_tree_empty(&mapping->i_mmap))
+	i_size_write(inode, offset);
+	mutex_lock(&mapping->i_mmap_mutex);
+	if (!RB_EMPTY_ROOT(&mapping->i_mmap))
 		hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
-	spin_unlock(&mapping->i_mmap_lock);
-	truncate_hugepages(mapping, offset);
+	mutex_unlock(&mapping->i_mmap_mutex);
+	truncate_hugepages(inode, offset);
 	return 0;
 }
 
 static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 {
 	struct inode *inode = dentry->d_inode;
+	struct hstate *h = hstate_inode(inode);
 	int error;
 	unsigned int ia_valid = attr->ia_valid;
 
@@ -372,39 +431,85 @@ static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
 
 	error = inode_change_ok(inode, attr);
 	if (error)
-		goto out;
+		return error;
 
 	if (ia_valid & ATTR_SIZE) {
 		error = -EINVAL;
-		if (!(attr->ia_size & ~HPAGE_MASK))
-			error = hugetlb_vmtruncate(inode, attr->ia_size);
+		if (attr->ia_size & ~huge_page_mask(h))
+			return -EINVAL;
+		error = hugetlb_vmtruncate(inode, attr->ia_size);
 		if (error)
-			goto out;
-		attr->ia_valid &= ~ATTR_SIZE;
+			return error;
 	}
-	error = inode_setattr(inode, attr);
-out:
-	return error;
+
+	setattr_copy(inode, attr);
+	mark_inode_dirty(inode);
+	return 0;
+}
+
+static struct inode *hugetlbfs_get_root(struct super_block *sb,
+					struct hugetlbfs_config *config)
+{
+	struct inode *inode;
+
+	inode = new_inode(sb);
+	if (inode) {
+		struct hugetlbfs_inode_info *info;
+		inode->i_ino = get_next_ino();
+		inode->i_mode = S_IFDIR | config->mode;
+		inode->i_uid = config->uid;
+		inode->i_gid = config->gid;
+		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+		info = HUGETLBFS_I(inode);
+		mpol_shared_policy_init(&info->policy, NULL);
+		inode->i_op = &hugetlbfs_dir_inode_operations;
+		inode->i_fop = &simple_dir_operations;
+		/* directory inodes start off with i_nlink == 2 (for "." entry) */
+		inc_nlink(inode);
+		lockdep_annotate_inode_mutex_key(inode);
+	}
+	return inode;
 }
 
-static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid, 
-					gid_t gid, int mode, dev_t dev)
+/*
+ * Hugetlbfs is not reclaimable; therefore its i_mmap_mutex will never
+ * be taken from reclaim -- unlike regular filesystems. This needs an
+ * annotation because huge_pmd_share() does an allocation under
+ * i_mmap_mutex.
+ */
+static struct lock_class_key hugetlbfs_i_mmap_mutex_key;
+
+static struct inode *hugetlbfs_get_inode(struct super_block *sb,
+					struct inode *dir,
+					umode_t mode, dev_t dev)
 {
 	struct inode *inode;
+	struct resv_map *resv_map;
+
+	resv_map = resv_map_alloc();
+	if (!resv_map)
+		return NULL;
 
 	inode = new_inode(sb);
 	if (inode) {
 		struct hugetlbfs_inode_info *info;
-		inode->i_mode = mode;
-		inode->i_uid = uid;
-		inode->i_gid = gid;
-		inode->i_blksize = HPAGE_SIZE;
-		inode->i_blocks = 0;
+		inode->i_ino = get_next_ino();
+		inode_init_owner(inode, dir, mode);
+		lockdep_set_class(&inode->i_mapping->i_mmap_mutex,
+				&hugetlbfs_i_mmap_mutex_key);
 		inode->i_mapping->a_ops = &hugetlbfs_aops;
 		inode->i_mapping->backing_dev_info =&hugetlbfs_backing_dev_info;
 		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+		inode->i_mapping->private_data = resv_map;
 		info = HUGETLBFS_I(inode);
-		mpol_shared_policy_init(&info->policy);
+		/*
+		 * The policy is initialized here even if we are creating a
+		 * private inode because initialization simply creates an
+		 * an empty rb tree and calls spin_lock_init(), later when we
+		 * call mpol_free_shared_policy() it will just return because
+		 * the rb tree will still be empty.
+		 */
+		mpol_shared_policy_init(&info->policy, NULL);
 		switch (mode & S_IFMT) {
 		default:
 			init_special_inode(inode, mode, dev);
@@ -418,13 +523,16 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
 			inode->i_fop = &simple_dir_operations;
 
 			/* directory inodes start off with i_nlink == 2 (for "." entry) */
-			inode->i_nlink++;
+			inc_nlink(inode);
 			break;
 		case S_IFLNK:
 			inode->i_op = &page_symlink_inode_operations;
 			break;
 		}
-	}
+		lockdep_annotate_inode_mutex_key(inode);
+	} else
+		kref_put(&resv_map->refs, resv_map_release);
+
 	return inode;
 }
 
@@ -432,20 +540,12 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb, uid_t uid,
  * File creation. Allocate an inode, and we're done..
  */
 static int hugetlbfs_mknod(struct inode *dir,
-			struct dentry *dentry, int mode, dev_t dev)
+			struct dentry *dentry, umode_t mode, dev_t dev)
 {
 	struct inode *inode;
 	int error = -ENOSPC;
-	gid_t gid;
-
-	if (dir->i_mode & S_ISGID) {
-		gid = dir->i_gid;
-		if (S_ISDIR(mode))
-			mode |= S_ISGID;
-	} else {
-		gid = current->fsgid;
-	}
-	inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid, gid, mode, dev);
+
+	inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
 	if (inode) {
 		dir->i_ctime = dir->i_mtime = CURRENT_TIME;
 		d_instantiate(dentry, inode);
@@ -455,15 +555,15 @@ static int hugetlbfs_mknod(struct inode *dir,
 	return error;
 }
 
-static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+static int hugetlbfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 {
 	int retval = hugetlbfs_mknod(dir, dentry, mode | S_IFDIR, 0);
 	if (!retval)
-		dir->i_nlink++;
+		inc_nlink(dir);
 	return retval;
 }
 
-static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd)
+static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
 {
 	return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
 }
@@ -473,15 +573,8 @@ static int hugetlbfs_symlink(struct inode *dir,
 {
 	struct inode *inode;
 	int error = -ENOSPC;
-	gid_t gid;
-
-	if (dir->i_mode & S_ISGID)
-		gid = dir->i_gid;
-	else
-		gid = current->fsgid;
 
-	inode = hugetlbfs_get_inode(dir->i_sb, current->fsuid,
-					gid, S_IFLNK|S_IRWXUGO, 0);
+	inode = hugetlbfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
 	if (inode) {
 		int l = strlen(symname)+1;
 		error = page_symlink(inode, symname, l);
@@ -497,25 +590,53 @@ static int hugetlbfs_symlink(struct inode *dir,
 }
 
 /*
- * For direct-IO reads into hugetlb pages
+ * mark the head page dirty
  */
 static int hugetlbfs_set_page_dirty(struct page *page)
 {
+	struct page *head = compound_head(page);
+
+	SetPageDirty(head);
 	return 0;
 }
 
-static int hugetlbfs_statfs(struct super_block *sb, struct kstatfs *buf)
+static int hugetlbfs_migrate_page(struct address_space *mapping,
+				struct page *newpage, struct page *page,
+				enum migrate_mode mode)
 {
-	struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
+	int rc;
+
+	rc = migrate_huge_page_move_mapping(mapping, newpage, page);
+	if (rc != MIGRATEPAGE_SUCCESS)
+		return rc;
+	migrate_page_copy(newpage, page);
+
+	return MIGRATEPAGE_SUCCESS;
+}
+
+static int hugetlbfs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(dentry->d_sb);
+	struct hstate *h = hstate_inode(dentry->d_inode);
 
 	buf->f_type = HUGETLBFS_MAGIC;
-	buf->f_bsize = HPAGE_SIZE;
+	buf->f_bsize = huge_page_size(h);
 	if (sbinfo) {
 		spin_lock(&sbinfo->stat_lock);
-		buf->f_blocks = sbinfo->max_blocks;
-		buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
-		buf->f_files = sbinfo->max_inodes;
-		buf->f_ffree = sbinfo->free_inodes;
+		/* If no limits set, just report 0 for max/free/used
+		 * blocks, like simple_statfs() */
+		if (sbinfo->spool) {
+			long free_pages;
+
+			spin_lock(&sbinfo->spool->lock);
+			buf->f_blocks = sbinfo->spool->max_hpages;
+			free_pages = sbinfo->spool->max_hpages
+				- sbinfo->spool->used_hpages;
+			buf->f_bavail = buf->f_bfree = free_pages;
+			spin_unlock(&sbinfo->spool->lock);
+			buf->f_files = sbinfo->max_inodes;
+			buf->f_ffree = sbinfo->free_inodes;
+		}
 		spin_unlock(&sbinfo->stat_lock);
 	}
 	buf->f_namelen = NAME_MAX;
@@ -528,6 +649,10 @@ static void hugetlbfs_put_super(struct super_block *sb)
 
 	if (sbi) {
 		sb->s_fs_info = NULL;
+
+		if (sbi->spool)
+			hugepage_put_subpool(sbi->spool);
+
 		kfree(sbi);
 	}
 }
@@ -557,7 +682,7 @@ static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
 }
 
 
-static kmem_cache_t *hugetlbfs_inode_cachep;
+static struct kmem_cache *hugetlbfs_inode_cachep;
 
 static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 {
@@ -566,7 +691,7 @@ static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 
 	if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
 		return NULL;
-	p = kmem_cache_alloc(hugetlbfs_inode_cachep, SLAB_KERNEL);
+	p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
 	if (unlikely(!p)) {
 		hugetlbfs_inc_free_inodes(sbinfo);
 		return NULL;
@@ -574,37 +699,43 @@ static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
 	return &p->vfs_inode;
 }
 
+static void hugetlbfs_i_callback(struct rcu_head *head)
+{
+	struct inode *inode = container_of(head, struct inode, i_rcu);
+	kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
+}
+
 static void hugetlbfs_destroy_inode(struct inode *inode)
 {
 	hugetlbfs_inc_free_inodes(HUGETLBFS_SB(inode->i_sb));
 	mpol_free_shared_policy(&HUGETLBFS_I(inode)->policy);
-	kmem_cache_free(hugetlbfs_inode_cachep, HUGETLBFS_I(inode));
+	call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
 }
 
-static struct address_space_operations hugetlbfs_aops = {
-	.readpage	= hugetlbfs_readpage,
-	.prepare_write	= hugetlbfs_prepare_write,
-	.commit_write	= hugetlbfs_commit_write,
+static const struct address_space_operations hugetlbfs_aops = {
+	.write_begin	= hugetlbfs_write_begin,
+	.write_end	= hugetlbfs_write_end,
 	.set_page_dirty	= hugetlbfs_set_page_dirty,
+	.migratepage    = hugetlbfs_migrate_page,
 };
 
 
-static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags)
+static void init_once(void *foo)
 {
 	struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
 
-	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
-	    SLAB_CTOR_CONSTRUCTOR)
-		inode_init_once(&ei->vfs_inode);
+	inode_init_once(&ei->vfs_inode);
 }
 
-struct file_operations hugetlbfs_file_operations = {
+const struct file_operations hugetlbfs_file_operations = {
+	.read			= hugetlbfs_read,
 	.mmap			= hugetlbfs_file_mmap,
-	.fsync			= simple_sync_file,
+	.fsync			= noop_fsync,
 	.get_unmapped_area	= hugetlb_get_unmapped_area,
+	.llseek		= default_llseek,
 };
 
-static struct inode_operations hugetlbfs_dir_inode_operations = {
+static const struct inode_operations hugetlbfs_dir_inode_operations = {
 	.create		= hugetlbfs_create,
 	.lookup		= simple_lookup,
 	.link		= simple_link,
@@ -617,81 +748,131 @@ static struct inode_operations hugetlbfs_dir_inode_operations = {
 	.setattr	= hugetlbfs_setattr,
 };
 
-static struct inode_operations hugetlbfs_inode_operations = {
+static const struct inode_operations hugetlbfs_inode_operations = {
 	.setattr	= hugetlbfs_setattr,
 };
 
-static struct super_operations hugetlbfs_ops = {
+static const struct super_operations hugetlbfs_ops = {
 	.alloc_inode    = hugetlbfs_alloc_inode,
 	.destroy_inode  = hugetlbfs_destroy_inode,
+	.evict_inode	= hugetlbfs_evict_inode,
 	.statfs		= hugetlbfs_statfs,
-	.delete_inode	= hugetlbfs_delete_inode,
-	.drop_inode	= hugetlbfs_drop_inode,
 	.put_super	= hugetlbfs_put_super,
+	.show_options	= generic_show_options,
 };
 
 static int
 hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
 {
-	char *opt, *value, *rest;
+	char *p, *rest;
+	substring_t args[MAX_OPT_ARGS];
+	int option;
+	unsigned long long size = 0;
+	enum { NO_SIZE, SIZE_STD, SIZE_PERCENT } setsize = NO_SIZE;
 
 	if (!options)
 		return 0;
-	while ((opt = strsep(&options, ",")) != NULL) {
-		if (!*opt)
+
+	while ((p = strsep(&options, ",")) != NULL) {
+		int token;
+		if (!*p)
 			continue;
 
-		value = strchr(opt, '=');
-		if (!value || !*value)
-			return -EINVAL;
-		else
-			*value++ = '\0';
-
-		if (!strcmp(opt, "uid"))
-			pconfig->uid = simple_strtoul(value, &value, 0);
-		else if (!strcmp(opt, "gid"))
-			pconfig->gid = simple_strtoul(value, &value, 0);
-		else if (!strcmp(opt, "mode"))
-			pconfig->mode = simple_strtoul(value,&value,0) & 0777U;
-		else if (!strcmp(opt, "size")) {
-			unsigned long long size = memparse(value, &rest);
-			if (*rest == '%') {
-				size <<= HPAGE_SHIFT;
-				size *= max_huge_pages;
-				do_div(size, 100);
-				rest++;
+		token = match_token(p, tokens, args);
+		switch (token) {
+		case Opt_uid:
+			if (match_int(&args[0], &option))
+ 				goto bad_val;
+			pconfig->uid = make_kuid(current_user_ns(), option);
+			if (!uid_valid(pconfig->uid))
+				goto bad_val;
+			break;
+
+		case Opt_gid:
+			if (match_int(&args[0], &option))
+ 				goto bad_val;
+			pconfig->gid = make_kgid(current_user_ns(), option);
+			if (!gid_valid(pconfig->gid))
+				goto bad_val;
+			break;
+
+		case Opt_mode:
+			if (match_octal(&args[0], &option))
+ 				goto bad_val;
+			pconfig->mode = option & 01777U;
+			break;
+
+		case Opt_size: {
+			/* memparse() will accept a K/M/G without a digit */
+			if (!isdigit(*args[0].from))
+				goto bad_val;
+			size = memparse(args[0].from, &rest);
+			setsize = SIZE_STD;
+			if (*rest == '%')
+				setsize = SIZE_PERCENT;
+			break;
+		}
+
+		case Opt_nr_inodes:
+			/* memparse() will accept a K/M/G without a digit */
+			if (!isdigit(*args[0].from))
+				goto bad_val;
+			pconfig->nr_inodes = memparse(args[0].from, &rest);
+			break;
+
+		case Opt_pagesize: {
+			unsigned long ps;
+			ps = memparse(args[0].from, &rest);
+			pconfig->hstate = size_to_hstate(ps);
+			if (!pconfig->hstate) {
+				pr_err("Unsupported page size %lu MB\n",
+					ps >> 20);
+				return -EINVAL;
 			}
-			size &= HPAGE_MASK;
-			pconfig->nr_blocks = (size >> HPAGE_SHIFT);
-			value = rest;
-		} else if (!strcmp(opt,"nr_inodes")) {
-			pconfig->nr_inodes = memparse(value, &rest);
-			value = rest;
-		} else
-			return -EINVAL;
+			break;
+		}
 
-		if (*value)
+		default:
+			pr_err("Bad mount option: \"%s\"\n", p);
 			return -EINVAL;
+			break;
+		}
+	}
+
+	/* Do size after hstate is set up */
+	if (setsize > NO_SIZE) {
+		struct hstate *h = pconfig->hstate;
+		if (setsize == SIZE_PERCENT) {
+			size <<= huge_page_shift(h);
+			size *= h->max_huge_pages;
+			do_div(size, 100);
+		}
+		pconfig->nr_blocks = (size >> huge_page_shift(h));
 	}
+
 	return 0;
+
+bad_val:
+	pr_err("Bad value '%s' for mount option '%s'\n", args[0].from, p);
+ 	return -EINVAL;
 }
 
 static int
 hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 {
-	struct inode * inode;
-	struct dentry * root;
 	int ret;
 	struct hugetlbfs_config config;
 	struct hugetlbfs_sb_info *sbinfo;
 
+	save_mount_options(sb, data);
+
 	config.nr_blocks = -1; /* No limit on size by default */
 	config.nr_inodes = -1; /* No limit on number of inodes by default */
-	config.uid = current->fsuid;
-	config.gid = current->fsgid;
+	config.uid = current_fsuid();
+	config.gid = current_fsgid();
 	config.mode = 0755;
+	config.hstate = &default_hstate;
 	ret = hugetlbfs_parse_options(data, &config);
-
 	if (ret)
 		return ret;
 
@@ -699,189 +880,218 @@ hugetlbfs_fill_super(struct super_block *sb, void *data, int silent)
 	if (!sbinfo)
 		return -ENOMEM;
 	sb->s_fs_info = sbinfo;
+	sbinfo->hstate = config.hstate;
 	spin_lock_init(&sbinfo->stat_lock);
-	sbinfo->max_blocks = config.nr_blocks;
-	sbinfo->free_blocks = config.nr_blocks;
 	sbinfo->max_inodes = config.nr_inodes;
 	sbinfo->free_inodes = config.nr_inodes;
+	sbinfo->spool = NULL;
+	if (config.nr_blocks != -1) {
+		sbinfo->spool = hugepage_new_subpool(config.nr_blocks);
+		if (!sbinfo->spool)
+			goto out_free;
+	}
 	sb->s_maxbytes = MAX_LFS_FILESIZE;
-	sb->s_blocksize = HPAGE_SIZE;
-	sb->s_blocksize_bits = HPAGE_SHIFT;
+	sb->s_blocksize = huge_page_size(config.hstate);
+	sb->s_blocksize_bits = huge_page_shift(config.hstate);
 	sb->s_magic = HUGETLBFS_MAGIC;
 	sb->s_op = &hugetlbfs_ops;
 	sb->s_time_gran = 1;
-	inode = hugetlbfs_get_inode(sb, config.uid, config.gid,
-					S_IFDIR | config.mode, 0);
-	if (!inode)
+	sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config));
+	if (!sb->s_root)
 		goto out_free;
-
-	root = d_alloc_root(inode);
-	if (!root) {
-		iput(inode);
-		goto out_free;
-	}
-	sb->s_root = root;
 	return 0;
 out_free:
+	kfree(sbinfo->spool);
 	kfree(sbinfo);
 	return -ENOMEM;
 }
 
-int hugetlb_get_quota(struct address_space *mapping)
-{
-	int ret = 0;
-	struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
-
-	if (sbinfo->free_blocks > -1) {
-		spin_lock(&sbinfo->stat_lock);
-		if (sbinfo->free_blocks > 0)
-			sbinfo->free_blocks--;
-		else
-			ret = -ENOMEM;
-		spin_unlock(&sbinfo->stat_lock);
-	}
-
-	return ret;
-}
-
-void hugetlb_put_quota(struct address_space *mapping)
-{
-	struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(mapping->host->i_sb);
-
-	if (sbinfo->free_blocks > -1) {
-		spin_lock(&sbinfo->stat_lock);
-		sbinfo->free_blocks++;
-		spin_unlock(&sbinfo->stat_lock);
-	}
-}
-
-static struct super_block *hugetlbfs_get_sb(struct file_system_type *fs_type,
+static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
 	int flags, const char *dev_name, void *data)
 {
-	return get_sb_nodev(fs_type, flags, data, hugetlbfs_fill_super);
+	return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
 }
 
 static struct file_system_type hugetlbfs_fs_type = {
 	.name		= "hugetlbfs",
-	.get_sb		= hugetlbfs_get_sb,
+	.mount		= hugetlbfs_mount,
 	.kill_sb	= kill_litter_super,
 };
+MODULE_ALIAS_FS("hugetlbfs");
 
-static struct vfsmount *hugetlbfs_vfsmount;
+static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
 
-/*
- * Return the next identifier for a shm file
- */
-static unsigned long hugetlbfs_counter(void)
+static int can_do_hugetlb_shm(void)
 {
-	static DEFINE_SPINLOCK(lock);
-	static unsigned long counter;
-	unsigned long ret;
-
-	spin_lock(&lock);
-	ret = ++counter;
-	spin_unlock(&lock);
-	return ret;
+	kgid_t shm_group;
+	shm_group = make_kgid(&init_user_ns, sysctl_hugetlb_shm_group);
+	return capable(CAP_IPC_LOCK) || in_group_p(shm_group);
 }
 
-static int can_do_hugetlb_shm(void)
+static int get_hstate_idx(int page_size_log)
 {
-	return likely(capable(CAP_IPC_LOCK) ||
-			in_group_p(sysctl_hugetlb_shm_group) ||
-			can_do_mlock());
+	struct hstate *h = hstate_sizelog(page_size_log);
+
+	if (!h)
+		return -1;
+	return h - hstates;
 }
 
-struct file *hugetlb_zero_setup(size_t size)
+static const struct dentry_operations anon_ops = {
+	.d_dname = simple_dname
+};
+
+/*
+ * Note that size should be aligned to proper hugepage size in caller side,
+ * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
+ */
+struct file *hugetlb_file_setup(const char *name, size_t size,
+				vm_flags_t acctflag, struct user_struct **user,
+				int creat_flags, int page_size_log)
 {
-	int error = -ENOMEM;
-	struct file *file;
+	struct file *file = ERR_PTR(-ENOMEM);
 	struct inode *inode;
-	struct dentry *dentry, *root;
+	struct path path;
+	struct super_block *sb;
 	struct qstr quick_string;
-	char buf[16];
-
-	if (!can_do_hugetlb_shm())
-		return ERR_PTR(-EPERM);
-
-	if (!is_hugepage_mem_enough(size))
-		return ERR_PTR(-ENOMEM);
-
-	if (!user_shm_lock(size, current->user))
-		return ERR_PTR(-ENOMEM);
+	int hstate_idx;
+
+	hstate_idx = get_hstate_idx(page_size_log);
+	if (hstate_idx < 0)
+		return ERR_PTR(-ENODEV);
+
+	*user = NULL;
+	if (!hugetlbfs_vfsmount[hstate_idx])
+		return ERR_PTR(-ENOENT);
+
+	if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
+		*user = current_user();
+		if (user_shm_lock(size, *user)) {
+			task_lock(current);
+			pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
+				current->comm, current->pid);
+			task_unlock(current);
+		} else {
+			*user = NULL;
+			return ERR_PTR(-EPERM);
+		}
+	}
 
-	root = hugetlbfs_vfsmount->mnt_root;
-	snprintf(buf, 16, "%lu", hugetlbfs_counter());
-	quick_string.name = buf;
+	sb = hugetlbfs_vfsmount[hstate_idx]->mnt_sb;
+	quick_string.name = name;
 	quick_string.len = strlen(quick_string.name);
 	quick_string.hash = 0;
-	dentry = d_alloc(root, &quick_string);
-	if (!dentry)
+	path.dentry = d_alloc_pseudo(sb, &quick_string);
+	if (!path.dentry)
 		goto out_shm_unlock;
 
-	error = -ENFILE;
-	file = get_empty_filp();
-	if (!file)
+	d_set_d_op(path.dentry, &anon_ops);
+	path.mnt = mntget(hugetlbfs_vfsmount[hstate_idx]);
+	file = ERR_PTR(-ENOSPC);
+	inode = hugetlbfs_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0);
+	if (!inode)
 		goto out_dentry;
 
-	error = -ENOSPC;
-	inode = hugetlbfs_get_inode(root->d_sb, current->fsuid,
-				current->fsgid, S_IFREG | S_IRWXUGO, 0);
-	if (!inode)
-		goto out_file;
+	file = ERR_PTR(-ENOMEM);
+	if (hugetlb_reserve_pages(inode, 0,
+			size >> huge_page_shift(hstate_inode(inode)), NULL,
+			acctflag))
+		goto out_inode;
 
-	d_instantiate(dentry, inode);
+	d_instantiate(path.dentry, inode);
 	inode->i_size = size;
-	inode->i_nlink = 0;
-	file->f_vfsmnt = mntget(hugetlbfs_vfsmount);
-	file->f_dentry = dentry;
-	file->f_mapping = inode->i_mapping;
-	file->f_op = &hugetlbfs_file_operations;
-	file->f_mode = FMODE_WRITE | FMODE_READ;
+	clear_nlink(inode);
+
+	file = alloc_file(&path, FMODE_WRITE | FMODE_READ,
+			&hugetlbfs_file_operations);
+	if (IS_ERR(file))
+		goto out_dentry; /* inode is already attached */
+
 	return file;
 
-out_file:
-	put_filp(file);
+out_inode:
+	iput(inode);
 out_dentry:
-	dput(dentry);
+	path_put(&path);
 out_shm_unlock:
-	user_shm_unlock(size, current->user);
-	return ERR_PTR(error);
+	if (*user) {
+		user_shm_unlock(size, *user);
+		*user = NULL;
+	}
+	return file;
 }
 
 static int __init init_hugetlbfs_fs(void)
 {
+	struct hstate *h;
 	int error;
-	struct vfsmount *vfsmount;
+	int i;
 
+	if (!hugepages_supported()) {
+		pr_info("disabling because there are no supported hugepage sizes\n");
+		return -ENOTSUPP;
+	}
+
+	error = bdi_init(&hugetlbfs_backing_dev_info);
+	if (error)
+		return error;
+
+	error = -ENOMEM;
 	hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
 					sizeof(struct hugetlbfs_inode_info),
-					0, 0, init_once, NULL);
+					0, 0, init_once);
 	if (hugetlbfs_inode_cachep == NULL)
-		return -ENOMEM;
+		goto out2;
 
 	error = register_filesystem(&hugetlbfs_fs_type);
 	if (error)
 		goto out;
 
-	vfsmount = kern_mount(&hugetlbfs_fs_type);
+	i = 0;
+	for_each_hstate(h) {
+		char buf[50];
+		unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10);
 
-	if (!IS_ERR(vfsmount)) {
-		hugetlbfs_vfsmount = vfsmount;
-		return 0;
-	}
+		snprintf(buf, sizeof(buf), "pagesize=%uK", ps_kb);
+		hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type,
+							buf);
 
-	error = PTR_ERR(vfsmount);
+		if (IS_ERR(hugetlbfs_vfsmount[i])) {
+			pr_err("Cannot mount internal hugetlbfs for "
+				"page size %uK", ps_kb);
+			error = PTR_ERR(hugetlbfs_vfsmount[i]);
+			hugetlbfs_vfsmount[i] = NULL;
+		}
+		i++;
+	}
+	/* Non default hstates are optional */
+	if (!IS_ERR_OR_NULL(hugetlbfs_vfsmount[default_hstate_idx]))
+		return 0;
 
  out:
-	if (error)
-		kmem_cache_destroy(hugetlbfs_inode_cachep);
+	kmem_cache_destroy(hugetlbfs_inode_cachep);
+ out2:
+	bdi_destroy(&hugetlbfs_backing_dev_info);
 	return error;
 }
 
 static void __exit exit_hugetlbfs_fs(void)
 {
+	struct hstate *h;
+	int i;
+
+
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
 	kmem_cache_destroy(hugetlbfs_inode_cachep);
+	i = 0;
+	for_each_hstate(h)
+		kern_unmount(hugetlbfs_vfsmount[i++]);
 	unregister_filesystem(&hugetlbfs_fs_type);
+	bdi_destroy(&hugetlbfs_backing_dev_info);
 }
 
 module_init(init_hugetlbfs_fs)