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/xattr.c b/fs/ext4/xattr.c
index f3a2f7e..c619a7e 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -267,7 +267,7 @@
 	void *end;
 	int error;
 
-	if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
+	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 		return -ENODATA;
 	error = ext4_get_inode_loc(inode, &iloc);
 	if (error)
@@ -396,7 +396,7 @@
 	void *end;
 	int error;
 
-	if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
+	if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
 		return 0;
 	error = ext4_get_inode_loc(inode, &iloc);
 	if (error)
@@ -908,7 +908,7 @@
 	is->s.base = is->s.first = IFIRST(header);
 	is->s.here = is->s.first;
 	is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
-	if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) {
+	if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) {
 		error = ext4_xattr_check_names(IFIRST(header), is->s.end);
 		if (error)
 			return error;
@@ -940,10 +940,10 @@
 	header = IHDR(inode, ext4_raw_inode(&is->iloc));
 	if (!IS_LAST_ENTRY(s->first)) {
 		header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
-		EXT4_I(inode)->i_state |= EXT4_STATE_XATTR;
+		ext4_set_inode_state(inode, EXT4_STATE_XATTR);
 	} else {
 		header->h_magic = cpu_to_le32(0);
-		EXT4_I(inode)->i_state &= ~EXT4_STATE_XATTR;
+		ext4_clear_inode_state(inode, EXT4_STATE_XATTR);
 	}
 	return 0;
 }
@@ -986,8 +986,8 @@
 	if (strlen(name) > 255)
 		return -ERANGE;
 	down_write(&EXT4_I(inode)->xattr_sem);
-	no_expand = EXT4_I(inode)->i_state & EXT4_STATE_NO_EXPAND;
-	EXT4_I(inode)->i_state |= EXT4_STATE_NO_EXPAND;
+	no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND);
+	ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND);
 
 	error = ext4_get_inode_loc(inode, &is.iloc);
 	if (error)
@@ -997,10 +997,10 @@
 	if (error)
 		goto cleanup;
 
-	if (EXT4_I(inode)->i_state & EXT4_STATE_NEW) {
+	if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) {
 		struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
 		memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
-		EXT4_I(inode)->i_state &= ~EXT4_STATE_NEW;
+		ext4_clear_inode_state(inode, EXT4_STATE_NEW);
 	}
 
 	error = ext4_xattr_ibody_find(inode, &i, &is);
@@ -1052,7 +1052,7 @@
 		ext4_xattr_update_super_block(handle, inode->i_sb);
 		inode->i_ctime = ext4_current_time(inode);
 		if (!value)
-			EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;
+			ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
 		error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
 		/*
 		 * The bh is consumed by ext4_mark_iloc_dirty, even with
@@ -1067,7 +1067,7 @@
 	brelse(is.iloc.bh);
 	brelse(bs.bh);
 	if (no_expand == 0)
-		EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND;
+		ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND);
 	up_write(&EXT4_I(inode)->xattr_sem);
 	return error;
 }