ext4: don't trash state flags in EXT4_IOC_SETFLAGS
Theodore Ts'o [Fri, 1 Jun 2012 03:46:01 +0000 (23:46 -0400)]
commit 79906964a187c405db72a3abc60eb9b50d804fbc upstream.

In commit 353eb83c we removed i_state_flags with 64-bit longs, But
when handling the EXT4_IOC_SETFLAGS ioctl, we replace i_flags
directly, which trashes the state flags which are stored in the high
32-bits of i_flags on 64-bit platforms.  So use the the
ext4_{set,clear}_inode_flags() functions which use atomic bit
manipulation functions instead.

Reported-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/ext4/ioctl.c

index 6eee255..e7eade8 100644 (file)
@@ -38,7 +38,7 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                handle_t *handle = NULL;
                int err, migrate = 0;
                struct ext4_iloc iloc;
-               unsigned int oldflags;
+               unsigned int oldflags, mask, i;
                unsigned int jflag;
 
                if (!inode_owner_or_capable(inode))
@@ -115,8 +115,14 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                if (err)
                        goto flags_err;
 
-               flags = flags & EXT4_FL_USER_MODIFIABLE;
-               flags |= oldflags & ~EXT4_FL_USER_MODIFIABLE;
+               for (i = 0, mask = 1; i < 32; i++, mask <<= 1) {
+                       if (!(mask & EXT4_FL_USER_MODIFIABLE))
+                               continue;
+                       if (mask & flags)
+                               ext4_set_inode_flag(inode, i);
+                       else
+                               ext4_clear_inode_flag(inode, i);
+               }
                ei->i_flags = flags;
 
                ext4_set_inode_flags(inode);