ext4: Use bitops to read/modify EXT4_I(inode)->i_state

At several places we modify EXT4_I(inode)->i_state without holding
i_mutex (ext4_release_file, ext4_bmap, ext4_journalled_writepage,
ext4_do_update_inode, ...). These modifications are racy and we can
lose updates to i_state. So convert handling of i_state to use bitops
which are atomic.

Cc: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 9630583..f6071ce 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -35,9 +35,9 @@
  */
 static int ext4_release_file(struct inode *inode, struct file *filp)
 {
-	if (EXT4_I(inode)->i_state & EXT4_STATE_DA_ALLOC_CLOSE) {
+	if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
 		ext4_alloc_da_blocks(inode);
-		EXT4_I(inode)->i_state &= ~EXT4_STATE_DA_ALLOC_CLOSE;
+		ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
 	}
 	/* if we are the last writer on the inode, drop the block reservation */
 	if ((filp->f_mode & FMODE_WRITE) &&