[LU-8891] disabling statahead changes dentry revalidation behavior

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.10.0
• Affects Version/s: Lustre 2.9.0
• Labels: llite
• Severity: 3
• Assignee: Steve Guminski (Inactive)
• Reporter: John Hammond

Description

In ll_revalidate_dentry() the test for LOOKUP_RCU in lookup_flags should probably go before the dentry_may_statahead() test:

static int ll_revalidate_dentry(struct dentry *dentry,
                                unsigned int lookup_flags)
{
        struct inode *dir = dentry->d_parent->d_inode;

        /* If this is intermediate component path lookup and we were able to get
         * to this dentry, then its lock has not been revoked and the
         * path component is valid. */
        if (lookup_flags & (LOOKUP_CONTINUE | LOOKUP_PARENT))
                return 1;

        /* Symlink - always valid as long as the dentry was found */
#ifdef HAVE_IOP_GET_LINK
        if (dentry->d_inode && dentry->d_inode->i_op->get_link)
#else
        if (dentry->d_inode && dentry->d_inode->i_op->follow_link)
#endif
                return 1;

        /*
         * VFS warns us that this is the second go around and previous
         * operation failed (most likely open|creat), so this time
         * we better talk to the server via the lookup path by name,
         * not by fid.
         */
        if (lookup_flags & LOOKUP_REVAL)
                return 0;

        if (!dentry_may_statahead(dir, dentry))
                return 1;

#ifndef HAVE_DCACHE_LOCK
        if (lookup_flags & LOOKUP_RCU)
                return -ECHILD;
#endif

        ll_statahead(dir, &dentry, dentry->d_inode == NULL);
        return 1;
}