diff --git a/mm/msync.c b/mm/msync.c
new file mode 100644
index 0000000..090f426
--- /dev/null
+++ b/mm/msync.c
@@ -0,0 +1,236 @@
+/*
+ *	linux/mm/msync.c
+ *
+ * Copyright (C) 1994-1999  Linus Torvalds
+ */
+
+/*
+ * The msync() system call.
+ */
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+#include <linux/mm.h>
+#include <linux/mman.h>
+#include <linux/hugetlb.h>
+#include <linux/syscalls.h>
+
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+
+/*
+ * Called with mm->page_table_lock held to protect against other
+ * threads/the swapper from ripping pte's out from under us.
+ */
+
+static void sync_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
+				unsigned long addr, unsigned long end)
+{
+	pte_t *pte;
+
+	pte = pte_offset_map(pmd, addr);
+	do {
+		unsigned long pfn;
+		struct page *page;
+
+		if (!pte_present(*pte))
+			continue;
+		pfn = pte_pfn(*pte);
+		if (!pfn_valid(pfn))
+			continue;
+		page = pfn_to_page(pfn);
+		if (PageReserved(page))
+			continue;
+
+		if (ptep_clear_flush_dirty(vma, addr, pte) ||
+		    page_test_and_clear_dirty(page))
+			set_page_dirty(page);
+	} while (pte++, addr += PAGE_SIZE, addr != end);
+	pte_unmap(pte - 1);
+}
+
+static inline void sync_pmd_range(struct vm_area_struct *vma, pud_t *pud,
+				unsigned long addr, unsigned long end)
+{
+	pmd_t *pmd;
+	unsigned long next;
+
+	pmd = pmd_offset(pud, addr);
+	do {
+		next = pmd_addr_end(addr, end);
+		if (pmd_none_or_clear_bad(pmd))
+			continue;
+		sync_pte_range(vma, pmd, addr, next);
+	} while (pmd++, addr = next, addr != end);
+}
+
+static inline void sync_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
+				unsigned long addr, unsigned long end)
+{
+	pud_t *pud;
+	unsigned long next;
+
+	pud = pud_offset(pgd, addr);
+	do {
+		next = pud_addr_end(addr, end);
+		if (pud_none_or_clear_bad(pud))
+			continue;
+		sync_pmd_range(vma, pud, addr, next);
+	} while (pud++, addr = next, addr != end);
+}
+
+static void sync_page_range(struct vm_area_struct *vma,
+				unsigned long addr, unsigned long end)
+{
+	struct mm_struct *mm = vma->vm_mm;
+	pgd_t *pgd;
+	unsigned long next;
+
+	/* For hugepages we can't go walking the page table normally,
+	 * but that's ok, hugetlbfs is memory based, so we don't need
+	 * to do anything more on an msync() */
+	if (is_vm_hugetlb_page(vma))
+		return;
+
+	BUG_ON(addr >= end);
+	pgd = pgd_offset(mm, addr);
+	flush_cache_range(vma, addr, end);
+	spin_lock(&mm->page_table_lock);
+	do {
+		next = pgd_addr_end(addr, end);
+		if (pgd_none_or_clear_bad(pgd))
+			continue;
+		sync_pud_range(vma, pgd, addr, next);
+	} while (pgd++, addr = next, addr != end);
+	spin_unlock(&mm->page_table_lock);
+}
+
+#ifdef CONFIG_PREEMPT
+static inline void filemap_sync(struct vm_area_struct *vma,
+				unsigned long addr, unsigned long end)
+{
+	const size_t chunk = 64 * 1024;	/* bytes */
+	unsigned long next;
+
+	do {
+		next = addr + chunk;
+		if (next > end || next < addr)
+			next = end;
+		sync_page_range(vma, addr, next);
+		cond_resched();
+	} while (addr = next, addr != end);
+}
+#else
+static inline void filemap_sync(struct vm_area_struct *vma,
+				unsigned long addr, unsigned long end)
+{
+	sync_page_range(vma, addr, end);
+}
+#endif
+
+/*
+ * MS_SYNC syncs the entire file - including mappings.
+ *
+ * MS_ASYNC does not start I/O (it used to, up to 2.5.67).  Instead, it just
+ * marks the relevant pages dirty.  The application may now run fsync() to
+ * write out the dirty pages and wait on the writeout and check the result.
+ * Or the application may run fadvise(FADV_DONTNEED) against the fd to start
+ * async writeout immediately.
+ * So my _not_ starting I/O in MS_ASYNC we provide complete flexibility to
+ * applications.
+ */
+static int msync_interval(struct vm_area_struct *vma,
+			unsigned long addr, unsigned long end, int flags)
+{
+	int ret = 0;
+	struct file *file = vma->vm_file;
+
+	if ((flags & MS_INVALIDATE) && (vma->vm_flags & VM_LOCKED))
+		return -EBUSY;
+
+	if (file && (vma->vm_flags & VM_SHARED)) {
+		filemap_sync(vma, addr, end);
+
+		if (flags & MS_SYNC) {
+			struct address_space *mapping = file->f_mapping;
+			int err;
+
+			ret = filemap_fdatawrite(mapping);
+			if (file->f_op && file->f_op->fsync) {
+				/*
+				 * We don't take i_sem here because mmap_sem
+				 * is already held.
+				 */
+				err = file->f_op->fsync(file,file->f_dentry,1);
+				if (err && !ret)
+					ret = err;
+			}
+			err = filemap_fdatawait(mapping);
+			if (!ret)
+				ret = err;
+		}
+	}
+	return ret;
+}
+
+asmlinkage long sys_msync(unsigned long start, size_t len, int flags)
+{
+	unsigned long end;
+	struct vm_area_struct *vma;
+	int unmapped_error, error = -EINVAL;
+
+	if (flags & MS_SYNC)
+		current->flags |= PF_SYNCWRITE;
+
+	down_read(&current->mm->mmap_sem);
+	if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC))
+		goto out;
+	if (start & ~PAGE_MASK)
+		goto out;
+	if ((flags & MS_ASYNC) && (flags & MS_SYNC))
+		goto out;
+	error = -ENOMEM;
+	len = (len + ~PAGE_MASK) & PAGE_MASK;
+	end = start + len;
+	if (end < start)
+		goto out;
+	error = 0;
+	if (end == start)
+		goto out;
+	/*
+	 * If the interval [start,end) covers some unmapped address ranges,
+	 * just ignore them, but return -ENOMEM at the end.
+	 */
+	vma = find_vma(current->mm, start);
+	unmapped_error = 0;
+	for (;;) {
+		/* Still start < end. */
+		error = -ENOMEM;
+		if (!vma)
+			goto out;
+		/* Here start < vma->vm_end. */
+		if (start < vma->vm_start) {
+			unmapped_error = -ENOMEM;
+			start = vma->vm_start;
+		}
+		/* Here vma->vm_start <= start < vma->vm_end. */
+		if (end <= vma->vm_end) {
+			if (start < end) {
+				error = msync_interval(vma, start, end, flags);
+				if (error)
+					goto out;
+			}
+			error = unmapped_error;
+			goto out;
+		}
+		/* Here vma->vm_start <= start < vma->vm_end < end. */
+		error = msync_interval(vma, start, vma->vm_end, flags);
+		if (error)
+			goto out;
+		start = vma->vm_end;
+		vma = vma->vm_next;
+	}
+out:
+	up_read(&current->mm->mmap_sem);
+	current->flags &= ~PF_SYNCWRITE;
+	return error;
+}