[LU-17486] race in ldiskfs_destroy_inode()

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.16.0
• Severity: 3
• Assignee: Alex Zhuravlev
• Reporter: Alex Zhuravlev

Description

static void ext4_destroy_inode(struct inode *inode)
{                           
        call_rcu(&inode->i_rcu, ext4_i_callback);

        if (EXT4_I(inode)->i_reserved_data_blocks)
                ext4_msg(inode->i_sb, KERN_ERR,
                         "Inode %lu (%p): i_reserved_data_blocks (%u) not cleared!",
                         inode->i_ino, EXT4_I(inode),
                         EXT4_I(inode)->i_reserved_data_blocks);
}       

on a preemption-enabled kernel ext4_i_callback() can race with the access to i_reserved_data_blocks a line below.