[LU-4310] __dquot_alloc_space() does not release i_lock in some cases

• Type: Bug
• Resolution: Fixed
• Priority: Blocker
• Fix Version/s: Lustre 2.6.0, Lustre 2.4.2, Lustre 2.5.1
• Affects Version/s: Lustre 2.5.0
• Severity: 3
• Assignee: Johann Lombardi (Inactive)
• Reporter: Johann Lombardi (Inactive)

Description

The patch removing the dqptr sem seems to have introduced a regression. In __dquot_alloc_space(), the i_lock is not released if we exit through the goto out_flush_warn.

int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags)
...
        spin_lock(&inode->i_lock);
...
        spin_lock(&dq_data_lock);
...
                if (check_bdq(dquot[cnt], number, warn, warntype+cnt)
                    == NO_QUOTA && !nofail) {
                        ret = NO_QUOTA;
                        spin_unlock(&dq_data_lock);
                        goto out_flush_warn;
                }
...
out_flush_warn:
        flush_warnings(dquot, warntype);
        for (cnt = 0; cnt < MAXQUOTAS; cnt++)
                dqput(dquot[cnt]);
out:
        return ret;
}

Many thanks to Andrew Perepechko for reporting the problem.