+
+#if IS_ENABLED(CONFIG_NFS_V4_2)
+int
+pnfs_report_layoutstat(struct inode *inode, gfp_t gfp_flags)
+{
+ struct pnfs_layoutdriver_type *ld = NFS_SERVER(inode)->pnfs_curr_ld;
+ struct nfs_server *server = NFS_SERVER(inode);
+ struct nfs_inode *nfsi = NFS_I(inode);
+ struct nfs42_layoutstat_data *data;
+ struct pnfs_layout_hdr *hdr;
+ int status = 0;
+
+ if (!pnfs_enabled_sb(server) || !ld->prepare_layoutstats)
+ goto out;
+
+ if (!nfs_server_capable(inode, NFS_CAP_LAYOUTSTATS))
+ goto out;
+
+ if (test_and_set_bit(NFS_INO_LAYOUTSTATS, &nfsi->flags))
+ goto out;
+
+ spin_lock(&inode->i_lock);
+ if (!NFS_I(inode)->layout) {
+ spin_unlock(&inode->i_lock);
+ goto out;
+ }
+ hdr = NFS_I(inode)->layout;
+ pnfs_get_layout_hdr(hdr);
+ spin_unlock(&inode->i_lock);
+
+ data = kzalloc(sizeof(*data), gfp_flags);
+ if (!data) {
+ status = -ENOMEM;
+ goto out_put;
+ }
+
+ data->args.fh = NFS_FH(inode);
+ data->args.inode = inode;
+ nfs4_stateid_copy(&data->args.stateid, &hdr->plh_stateid);
+ status = ld->prepare_layoutstats(&data->args);
+ if (status)
+ goto out_free;
+
+ status = nfs42_proc_layoutstats_generic(NFS_SERVER(inode), data);
+
+out:
+ dprintk("%s returns %d\n", __func__, status);
+ return status;
+
+out_free:
+ kfree(data);
+out_put:
+ pnfs_put_layout_hdr(hdr);
+ smp_mb__before_atomic();
+ clear_bit(NFS_INO_LAYOUTSTATS, &nfsi->flags);
+ smp_mb__after_atomic();
+ goto out;
+}
+EXPORT_SYMBOL_GPL(pnfs_report_layoutstat);
+#endif
+
+unsigned int layoutstats_timer;
+module_param(layoutstats_timer, uint, 0644);
+EXPORT_SYMBOL_GPL(layoutstats_timer);