1 files changed, 19 insertions, 10 deletions

diff --git a/mm/madvise.c b/mm/madvise.c
index 1ccbba5b6674..14d260fa0d17 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -11,8 +11,11 @@
 #include <linux/mempolicy.h>
 #include <linux/page-isolation.h>
 #include <linux/hugetlb.h>
+#include <linux/falloc.h>
 #include <linux/sched.h>
 #include <linux/ksm.h>
+#include <linux/fs.h>
+#include <linux/file.h>
 
 /*
  * Any behaviour which results in changes to the vma->vm_flags needs to
@@ -200,33 +203,39 @@ static long madvise_remove(struct vm_area_struct *vma,
                                 struct vm_area_struct **prev,
                                 unsigned long start, unsigned long end)
 {
-        struct address_space *mapping;
-        loff_t offset, endoff;
+        loff_t offset;
         int error;
+        struct file *f;
 
         *prev = NULL;   /* tell sys_madvise we drop mmap_sem */
 
         if (vma->vm_flags & (VM_LOCKED|VM_NONLINEAR|VM_HUGETLB))
                 return -EINVAL;
 
-        if (!vma->vm_file || !vma->vm_file->f_mapping
-                || !vma->vm_file->f_mapping->host) {
+        f = vma->vm_file;
+
+        if (!f || !f->f_mapping || !f->f_mapping->host) {
                         return -EINVAL;
         }
 
         if ((vma->vm_flags & (VM_SHARED|VM_WRITE)) != (VM_SHARED|VM_WRITE))
                 return -EACCES;
 
-        mapping = vma->vm_file->f_mapping;
-
         offset = (loff_t)(start - vma->vm_start)
                         + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
-        endoff = (loff_t)(end - vma->vm_start - 1)
-                        + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 
-        /* vmtruncate_range needs to take i_mutex */
+        /*
+         * Filesystem's fallocate may need to take i_mutex.  We need to
+         * explicitly grab a reference because the vma (and hence the
+         * vma's reference to the file) can go away as soon as we drop
+         * mmap_sem.
+         */
+        get_file(f);
         up_read(&current->mm->mmap_sem);
-        error = vmtruncate_range(mapping->host, offset, endoff);
+        error = do_fallocate(f,
+                                FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+                                offset, end - start);
+        fput(f);
         down_read(&current->mm->mmap_sem);
         return error;
 }