[PATCH][SRU][TRUSTY] btrfs: filter invalid arg for btrfs resize

[Colin King]

From: Gui Hecheng <guihc.fnst at cn.fujitsu.com>

BugLink: http://bugs.launchpad.net/bugs/1435441

Originally following cmds will work:
	# btrfs fi resize -10A  <mnt>
	# btrfs fi resize -10Gaha <mnt>
Filter the arg by checking the return pointer of memparse.

Signed-off-by: Gui Hecheng <guihc.fnst at cn.fujitsu.com>
Signed-off-by: Chris Mason <clm at fb.com>
(cherry pick from upstream commit 9a40f1222a372de77344d85d31f8fe0e1c0e60e7)
Signed-off-by: Colin Ian King <colin.king at canonical.com>
---
 fs/btrfs/ioctl.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 5962236..05f8df8 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1472,6 +1472,7 @@ static noinline int btrfs_ioctl_resize(struct file *file,
 	struct btrfs_trans_handle *trans;
 	struct btrfs_device *device = NULL;
 	char *sizestr;
+	char *retptr;
 	char *devstr = NULL;
 	int ret = 0;
 	int mod = 0;
@@ -1539,8 +1540,8 @@ static noinline int btrfs_ioctl_resize(struct file *file,
 			mod = 1;
 			sizestr++;
 		}
-		new_size = memparse(sizestr, NULL);
-		if (new_size == 0) {
+		new_size = memparse(sizestr, &retptr);
+		if (*retptr != '\0' || new_size == 0) {
 			ret = -EINVAL;
 			goto out_free;
 		}
-- 
2.1.0