From: Miao Xie <miaox@cn.fujitsu.com>
Date: Thu, 20 May 2010 07:21:50 +0000 (+0000)
Subject: Btrfs: fix remap_file_pages error
X-Git-Tag: v2.6.35-rc3~3^2~13
X-Git-Url: https://bbs.cooldavid.org/git/?p=net-next-2.6.git;a=commitdiff_plain;h=058a457ef0ce28d595af53d6103db73332383cbc

Btrfs: fix remap_file_pages error

when we use remap_file_pages() to remap a file, remap_file_pages always return
error. It is because btrfs didn't set VM_CAN_NONLINEAR for vma.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
---

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index abcb91867b5..ce0cd29efa9 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1189,8 +1189,15 @@ static const struct vm_operations_struct btrfs_file_vm_ops = {
 
 static int btrfs_file_mmap(struct file	*filp, struct vm_area_struct *vma)
 {
-	vma->vm_ops = &btrfs_file_vm_ops;
+	struct address_space *mapping = filp->f_mapping;
+
+	if (!mapping->a_ops->readpage)
+		return -ENOEXEC;
+
 	file_accessed(filp);
+	vma->vm_ops = &btrfs_file_vm_ops;
+	vma->vm_flags |= VM_CAN_NONLINEAR;
+
 	return 0;
 }