ext4: don't trash state flags in EXT4_IOC_SETFLAGS

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>
Cc: stable@kernel.org

1 files changed, 9 insertions, 3 deletions

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index feba55a225a6..8ad112ae0ade 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -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);