Initial import

1 files changed, 1114 insertions, 0 deletions

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
new file mode 100644
index 000000000..87724c1d7
--- /dev/null
+++ b/fs/hugetlbfs/inode.c
@@ -0,0 +1,1114 @@
+/*
+ * hugetlbpage-backed filesystem.  Based on ramfs.
+ *
+ * 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>
+#include <linux/sched.h>		/* remove ASAP */
+#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/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 <linux/uio.h>
+
+#include <asm/uaccess.h>
+
+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	max_hpages;
+	long	nr_inodes;
+	struct hstate *hstate;
+	long    min_hpages;
+};
+
+struct hugetlbfs_inode_info {
+	struct shared_policy policy;
+	struct inode vfs_inode;
+};
+
+static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
+{
+	return container_of(inode, struct hugetlbfs_inode_info, vfs_inode);
+}
+
+int sysctl_hugetlb_shm_group;
+
+enum {
+	Opt_size, Opt_nr_inodes,
+	Opt_mode, Opt_uid, Opt_gid,
+	Opt_pagesize, Opt_min_size,
+	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_min_size,	"min_size=%s"},
+	{Opt_err,	NULL},
+};
+
+static void huge_pagevec_release(struct pagevec *pvec)
+{
+	int i;
+
+	for (i = 0; i < pagevec_count(pvec); ++i)
+		put_page(pvec->pages[i]);
+
+	pagevec_reinit(pvec);
+}
+
+static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	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_pgoff & (~huge_page_mask(h) >> PAGE_SHIFT))
+		return -EINVAL;
+
+	vma_len = (loff_t)(vma->vm_end - vma->vm_start);
+
+	mutex_lock(&inode->i_mutex);
+	file_accessed(file);
+
+	ret = -ENOMEM;
+	len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
+
+	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 (vma->vm_flags & VM_WRITE && inode->i_size < len)
+		inode->i_size = len;
+out:
+	mutex_unlock(&inode->i_mutex);
+
+	return ret;
+}
+
+/*
+ * Called under down_write(mmap_sem).
+ */
+
+#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;
+	struct hstate *h = hstate_file(file);
+	struct vm_unmapped_area_info info;
+
+	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, huge_page_size(h));
+		vma = find_vma(mm, addr);
+		if (TASK_SIZE - len >= addr &&
+		    (!vma || addr + len <= vma->vm_start))
+			return addr;
+	}
+
+	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
+
+static size_t
+hugetlbfs_read_actor(struct page *page, unsigned long offset,
+			struct iov_iter *to, unsigned long size)
+{
+	size_t copied = 0;
+	int i, chunksize;
+
+	/* Find which 4k chunk and offset with in that chunk */
+	i = offset >> PAGE_CACHE_SHIFT;
+	offset = offset & ~PAGE_CACHE_MASK;
+
+	while (size) {
+		size_t n;
+		chunksize = PAGE_CACHE_SIZE;
+		if (offset)
+			chunksize -= offset;
+		if (chunksize > size)
+			chunksize = size;
+		n = copy_page_to_iter(&page[i], offset, chunksize, to);
+		copied += n;
+		if (n != chunksize)
+			return copied;
+		offset = 0;
+		size -= chunksize;
+		i++;
+	}
+	return copied;
+}
+
+/*
+ * 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 ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to)
+{
+	struct file *file = iocb->ki_filp;
+	struct hstate *h = hstate_file(file);
+	struct address_space *mapping = file->f_mapping;
+	struct inode *inode = mapping->host;
+	unsigned long index = iocb->ki_pos >> huge_page_shift(h);
+	unsigned long offset = iocb->ki_pos & ~huge_page_mask(h);
+	unsigned long end_index;
+	loff_t isize;
+	ssize_t retval = 0;
+
+	while (iov_iter_count(to)) {
+		struct page *page;
+		size_t nr, copied;
+
+		/* nr is the maximum number of bytes to copy from this page */
+		nr = huge_page_size(h);
+		isize = i_size_read(inode);
+		if (!isize)
+			break;
+		end_index = (isize - 1) >> huge_page_shift(h);
+		if (index > end_index)
+			break;
+		if (index == end_index) {
+			nr = ((isize - 1) & ~huge_page_mask(h)) + 1;
+			if (nr <= offset)
+				break;
+		}
+		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.
+			 */
+			copied = iov_iter_zero(nr, to);
+		} else {
+			unlock_page(page);
+
+			/*
+			 * We have the page, copy it to user space buffer.
+			 */
+			copied = hugetlbfs_read_actor(page, offset, to, nr);
+			page_cache_release(page);
+		}
+		offset += copied;
+		retval += copied;
+		if (copied != nr && iov_iter_count(to)) {
+			if (!retval)
+				retval = -EFAULT;
+			break;
+		}
+		index += offset >> huge_page_shift(h);
+		offset &= ~huge_page_mask(h);
+	}
+	iocb->ki_pos = ((loff_t)index << huge_page_shift(h)) + offset;
+	return retval;
+}
+
+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_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)
+{
+	ClearPageDirty(page);
+	ClearPageUptodate(page);
+	delete_from_page_cache(page);
+}
+
+static void truncate_hugepages(struct inode *inode, loff_t lstart)
+{
+	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, freed = 0;
+
+	pagevec_init(&pvec, 0);
+	next = start;
+	while (1) {
+		if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
+			if (next == start)
+				break;
+			next = start;
+			continue;
+		}
+
+		for (i = 0; i < pagevec_count(&pvec); ++i) {
+			struct page *page = pvec.pages[i];
+
+			lock_page(page);
+			if (page->index > next)
+				next = page->index;
+			++next;
+			truncate_huge_page(page);
+			unlock_page(page);
+			freed++;
+		}
+		huge_pagevec_release(&pvec);
+	}
+	BUG_ON(!lstart && mapping->nrpages);
+	hugetlb_unreserve_pages(inode, start, freed);
+}
+
+static void hugetlbfs_evict_inode(struct inode *inode)
+{
+	struct resv_map *resv_map;
+
+	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);
+}
+
+static inline void
+hugetlb_vmtruncate_list(struct rb_root *root, pgoff_t pgoff)
+{
+	struct vm_area_struct *vma;
+
+	vma_interval_tree_foreach(vma, root, pgoff, ULONG_MAX) {
+		unsigned long v_offset;
+
+		/*
+		 * 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 (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, NULL);
+	}
+}
+
+static int hugetlb_vmtruncate(struct inode *inode, loff_t offset)
+{
+	pgoff_t pgoff;
+	struct address_space *mapping = inode->i_mapping;
+	struct hstate *h = hstate_inode(inode);
+
+	BUG_ON(offset & ~huge_page_mask(h));
+	pgoff = offset >> PAGE_SHIFT;
+
+	i_size_write(inode, offset);
+	i_mmap_lock_write(mapping);
+	if (!RB_EMPTY_ROOT(&mapping->i_mmap))
+		hugetlb_vmtruncate_list(&mapping->i_mmap, pgoff);
+	i_mmap_unlock_write(mapping);
+	truncate_hugepages(inode, offset);
+	return 0;
+}
+
+static int hugetlbfs_setattr(struct dentry *dentry, struct iattr *attr)
+{
+	struct inode *inode = d_inode(dentry);
+	struct hstate *h = hstate_inode(inode);
+	int error;
+	unsigned int ia_valid = attr->ia_valid;
+
+	BUG_ON(!inode);
+
+	error = inode_change_ok(inode, attr);
+	if (error)
+		return error;
+
+	if (ia_valid & ATTR_SIZE) {
+		error = -EINVAL;
+		if (attr->ia_size & ~huge_page_mask(h))
+			return -EINVAL;
+		error = hugetlb_vmtruncate(inode, attr->ia_size);
+		if (error)
+			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;
+}
+
+/*
+ * Hugetlbfs is not reclaimable; therefore its i_mmap_rwsem will never
+ * be taken from reclaim -- unlike regular filesystems. This needs an
+ * annotation because huge_pmd_share() does an allocation under
+ * i_mmap_rwsem.
+ */
+static struct lock_class_key hugetlbfs_i_mmap_rwsem_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_ino = get_next_ino();
+		inode_init_owner(inode, dir, mode);
+		lockdep_set_class(&inode->i_mapping->i_mmap_rwsem,
+				&hugetlbfs_i_mmap_rwsem_key);
+		inode->i_mapping->a_ops = &hugetlbfs_aops;
+		inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+		inode->i_mapping->private_data = resv_map;
+		info = HUGETLBFS_I(inode);
+		/*
+		 * 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);
+			break;
+		case S_IFREG:
+			inode->i_op = &hugetlbfs_inode_operations;
+			inode->i_fop = &hugetlbfs_file_operations;
+			break;
+		case S_IFDIR:
+			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);
+			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;
+}
+
+/*
+ * File creation. Allocate an inode, and we're done..
+ */
+static int hugetlbfs_mknod(struct inode *dir,
+			struct dentry *dentry, umode_t mode, dev_t dev)
+{
+	struct inode *inode;
+	int error = -ENOSPC;
+
+	inode = hugetlbfs_get_inode(dir->i_sb, dir, mode, dev);
+	if (inode) {
+		dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+		d_instantiate(dentry, inode);
+		dget(dentry);	/* Extra count - pin the dentry in core */
+		error = 0;
+	}
+	return error;
+}
+
+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)
+		inc_nlink(dir);
+	return retval;
+}
+
+static int hugetlbfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
+{
+	return hugetlbfs_mknod(dir, dentry, mode | S_IFREG, 0);
+}
+
+static int hugetlbfs_symlink(struct inode *dir,
+			struct dentry *dentry, const char *symname)
+{
+	struct inode *inode;
+	int error = -ENOSPC;
+
+	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);
+		if (!error) {
+			d_instantiate(dentry, inode);
+			dget(dentry);
+		} else
+			iput(inode);
+	}
+	dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+
+	return error;
+}
+
+/*
+ * 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_migrate_page(struct address_space *mapping,
+				struct page *newpage, struct page *page,
+				enum migrate_mode mode)
+{
+	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(d_inode(dentry));
+
+	buf->f_type = HUGETLBFS_MAGIC;
+	buf->f_bsize = huge_page_size(h);
+	if (sbinfo) {
+		spin_lock(&sbinfo->stat_lock);
+		/* 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;
+	return 0;
+}
+
+static void hugetlbfs_put_super(struct super_block *sb)
+{
+	struct hugetlbfs_sb_info *sbi = HUGETLBFS_SB(sb);
+
+	if (sbi) {
+		sb->s_fs_info = NULL;
+
+		if (sbi->spool)
+			hugepage_put_subpool(sbi->spool);
+
+		kfree(sbi);
+	}
+}
+
+static inline int hugetlbfs_dec_free_inodes(struct hugetlbfs_sb_info *sbinfo)
+{
+	if (sbinfo->free_inodes >= 0) {
+		spin_lock(&sbinfo->stat_lock);
+		if (unlikely(!sbinfo->free_inodes)) {
+			spin_unlock(&sbinfo->stat_lock);
+			return 0;
+		}
+		sbinfo->free_inodes--;
+		spin_unlock(&sbinfo->stat_lock);
+	}
+
+	return 1;
+}
+
+static void hugetlbfs_inc_free_inodes(struct hugetlbfs_sb_info *sbinfo)
+{
+	if (sbinfo->free_inodes >= 0) {
+		spin_lock(&sbinfo->stat_lock);
+		sbinfo->free_inodes++;
+		spin_unlock(&sbinfo->stat_lock);
+	}
+}
+
+
+static struct kmem_cache *hugetlbfs_inode_cachep;
+
+static struct inode *hugetlbfs_alloc_inode(struct super_block *sb)
+{
+	struct hugetlbfs_sb_info *sbinfo = HUGETLBFS_SB(sb);
+	struct hugetlbfs_inode_info *p;
+
+	if (unlikely(!hugetlbfs_dec_free_inodes(sbinfo)))
+		return NULL;
+	p = kmem_cache_alloc(hugetlbfs_inode_cachep, GFP_KERNEL);
+	if (unlikely(!p)) {
+		hugetlbfs_inc_free_inodes(sbinfo);
+		return NULL;
+	}
+	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);
+	call_rcu(&inode->i_rcu, hugetlbfs_i_callback);
+}
+
+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)
+{
+	struct hugetlbfs_inode_info *ei = (struct hugetlbfs_inode_info *)foo;
+
+	inode_init_once(&ei->vfs_inode);
+}
+
+const struct file_operations hugetlbfs_file_operations = {
+	.read_iter		= hugetlbfs_read_iter,
+	.mmap			= hugetlbfs_file_mmap,
+	.fsync			= noop_fsync,
+	.get_unmapped_area	= hugetlb_get_unmapped_area,
+	.llseek		= default_llseek,
+};
+
+static const struct inode_operations hugetlbfs_dir_inode_operations = {
+	.create		= hugetlbfs_create,
+	.lookup		= simple_lookup,
+	.link		= simple_link,
+	.unlink		= simple_unlink,
+	.symlink	= hugetlbfs_symlink,
+	.mkdir		= hugetlbfs_mkdir,
+	.rmdir		= simple_rmdir,
+	.mknod		= hugetlbfs_mknod,
+	.rename		= simple_rename,
+	.setattr	= hugetlbfs_setattr,
+};
+
+static const struct inode_operations hugetlbfs_inode_operations = {
+	.setattr	= hugetlbfs_setattr,
+};
+
+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,
+	.put_super	= hugetlbfs_put_super,
+	.show_options	= generic_show_options,
+};
+
+enum { NO_SIZE, SIZE_STD, SIZE_PERCENT };
+
+/*
+ * Convert size option passed from command line to number of huge pages
+ * in the pool specified by hstate.  Size option could be in bytes
+ * (val_type == SIZE_STD) or percentage of the pool (val_type == SIZE_PERCENT).
+ */
+static long long
+hugetlbfs_size_to_hpages(struct hstate *h, unsigned long long size_opt,
+								int val_type)
+{
+	if (val_type == NO_SIZE)
+		return -1;
+
+	if (val_type == SIZE_PERCENT) {
+		size_opt <<= huge_page_shift(h);
+		size_opt *= h->max_huge_pages;
+		do_div(size_opt, 100);
+	}
+
+	size_opt >>= huge_page_shift(h);
+	return size_opt;
+}
+
+static int
+hugetlbfs_parse_options(char *options, struct hugetlbfs_config *pconfig)
+{
+	char *p, *rest;
+	substring_t args[MAX_OPT_ARGS];
+	int option;
+	unsigned long long max_size_opt = 0, min_size_opt = 0;
+	int max_val_type = NO_SIZE, min_val_type = NO_SIZE;
+
+	if (!options)
+		return 0;
+
+	while ((p = strsep(&options, ",")) != NULL) {
+		int token;
+		if (!*p)
+			continue;
+
+		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;
+			max_size_opt = memparse(args[0].from, &rest);
+			max_val_type = SIZE_STD;
+			if (*rest == '%')
+				max_val_type = 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;
+			}
+			break;
+		}
+
+		case Opt_min_size: {
+			/* memparse() will accept a K/M/G without a digit */
+			if (!isdigit(*args[0].from))
+				goto bad_val;
+			min_size_opt = memparse(args[0].from, &rest);
+			min_val_type = SIZE_STD;
+			if (*rest == '%')
+				min_val_type = SIZE_PERCENT;
+			break;
+		}
+
+		default:
+			pr_err("Bad mount option: \"%s\"\n", p);
+			return -EINVAL;
+			break;
+		}
+	}
+
+	/*
+	 * Use huge page pool size (in hstate) to convert the size
+	 * options to number of huge pages.  If NO_SIZE, -1 is returned.
+	 */
+	pconfig->max_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
+						max_size_opt, max_val_type);
+	pconfig->min_hpages = hugetlbfs_size_to_hpages(pconfig->hstate,
+						min_size_opt, min_val_type);
+
+	/*
+	 * If max_size was specified, then min_size must be smaller
+	 */
+	if (max_val_type > NO_SIZE &&
+	    pconfig->min_hpages > pconfig->max_hpages) {
+		pr_err("minimum size can not be greater than maximum size\n");
+		return -EINVAL;
+	}
+
+	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)
+{
+	int ret;
+	struct hugetlbfs_config config;
+	struct hugetlbfs_sb_info *sbinfo;
+
+	save_mount_options(sb, data);
+
+	config.max_hpages = -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.mode = 0755;
+	config.hstate = &default_hstate;
+	config.min_hpages = -1; /* No default minimum size */
+	ret = hugetlbfs_parse_options(data, &config);
+	if (ret)
+		return ret;
+
+	sbinfo = kmalloc(sizeof(struct hugetlbfs_sb_info), GFP_KERNEL);
+	if (!sbinfo)
+		return -ENOMEM;
+	sb->s_fs_info = sbinfo;
+	sbinfo->hstate = config.hstate;
+	spin_lock_init(&sbinfo->stat_lock);
+	sbinfo->max_inodes = config.nr_inodes;
+	sbinfo->free_inodes = config.nr_inodes;
+	sbinfo->spool = NULL;
+	/*
+	 * Allocate and initialize subpool if maximum or minimum size is
+	 * specified.  Any needed reservations (for minimim size) are taken
+	 * taken when the subpool is created.
+	 */
+	if (config.max_hpages != -1 || config.min_hpages != -1) {
+		sbinfo->spool = hugepage_new_subpool(config.hstate,
+							config.max_hpages,
+							config.min_hpages);
+		if (!sbinfo->spool)
+			goto out_free;
+	}
+	sb->s_maxbytes = MAX_LFS_FILESIZE;
+	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;
+	sb->s_root = d_make_root(hugetlbfs_get_root(sb, &config));
+	if (!sb->s_root)
+		goto out_free;
+	return 0;
+out_free:
+	kfree(sbinfo->spool);
+	kfree(sbinfo);
+	return -ENOMEM;
+}
+
+static struct dentry *hugetlbfs_mount(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *data)
+{
+	return mount_nodev(fs_type, flags, data, hugetlbfs_fill_super);
+}
+
+static struct file_system_type hugetlbfs_fs_type = {
+	.name		= "hugetlbfs",
+	.mount		= hugetlbfs_mount,
+	.kill_sb	= kill_litter_super,
+};
+MODULE_ALIAS_FS("hugetlbfs");
+
+static struct vfsmount *hugetlbfs_vfsmount[HUGE_MAX_HSTATE];
+
+static int can_do_hugetlb_shm(void)
+{
+	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 get_hstate_idx(int page_size_log)
+{
+	struct hstate *h = hstate_sizelog(page_size_log);
+
+	if (!h)
+		return -1;
+	return h - hstates;
+}
+
+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)
+{
+	struct file *file = ERR_PTR(-ENOMEM);
+	struct inode *inode;
+	struct path path;
+	struct super_block *sb;
+	struct qstr quick_string;
+	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);
+		}
+	}
+
+	sb = hugetlbfs_vfsmount[hstate_idx]->mnt_sb;
+	quick_string.name = name;
+	quick_string.len = strlen(quick_string.name);
+	quick_string.hash = 0;
+	path.dentry = d_alloc_pseudo(sb, &quick_string);
+	if (!path.dentry)
+		goto out_shm_unlock;
+
+	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;
+
+	file = ERR_PTR(-ENOMEM);
+	if (hugetlb_reserve_pages(inode, 0,
+			size >> huge_page_shift(hstate_inode(inode)), NULL,
+			acctflag))
+		goto out_inode;
+
+	d_instantiate(path.dentry, inode);
+	inode->i_size = size;
+	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_inode:
+	iput(inode);
+out_dentry:
+	path_put(&path);
+out_shm_unlock:
+	if (*user) {
+		user_shm_unlock(size, *user);
+		*user = NULL;
+	}
+	return file;
+}
+
+static int __init init_hugetlbfs_fs(void)
+{
+	struct hstate *h;
+	int error;
+	int i;
+
+	if (!hugepages_supported()) {
+		pr_info("disabling because there are no supported hugepage sizes\n");
+		return -ENOTSUPP;
+	}
+
+	error = -ENOMEM;
+	hugetlbfs_inode_cachep = kmem_cache_create("hugetlbfs_inode_cache",
+					sizeof(struct hugetlbfs_inode_info),
+					0, 0, init_once);
+	if (hugetlbfs_inode_cachep == NULL)
+		goto out2;
+
+	error = register_filesystem(&hugetlbfs_fs_type);
+	if (error)
+		goto out;
+
+	i = 0;
+	for_each_hstate(h) {
+		char buf[50];
+		unsigned ps_kb = 1U << (h->order + PAGE_SHIFT - 10);
+
+		snprintf(buf, sizeof(buf), "pagesize=%uK", ps_kb);
+		hugetlbfs_vfsmount[i] = kern_mount_data(&hugetlbfs_fs_type,
+							buf);
+
+		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:
+	kmem_cache_destroy(hugetlbfs_inode_cachep);
+ out2:
+	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);
+}
+
+module_init(init_hugetlbfs_fs)
+module_exit(exit_hugetlbfs_fs)
+
+MODULE_LICENSE("GPL");