NFSv4.1/flexfiles: Remove mirror backpointer to lseg.

When we start sharing mirrors between several lsegs, we won't be able to
keep it.

Signed-off-by: Trond Myklebust <[e-mail]>

fs/nfs/flexfilelayout/flexfilelayout.c

···
 		}
 
 		fls->mirror_array[i]->ds_count = ds_count;
-		fls->mirror_array[i]->lseg = &fls->generic_hdr;
 
 		/* deviceid */
 		rc = decode_deviceid(&stream, &devid);
···
 }
 
 static void
-nfs4_ff_layout_stat_io_start_read(struct nfs4_ff_layout_mirror *mirror,
+nfs4_ff_layout_stat_io_start_read(struct inode *inode,
+		struct nfs4_ff_layout_mirror *mirror,
 		__u64 requested, ktime_t now)
 {
 	bool report;
···
 	spin_unlock(&mirror->lock);
 
 	if (report)
-		pnfs_report_layoutstat(mirror->lseg->pls_layout->plh_inode,
-				GFP_KERNEL);
+		pnfs_report_layoutstat(inode, GFP_KERNEL);
 }
 
 static void
···
 }
 
 static void
-nfs4_ff_layout_stat_io_start_write(struct nfs4_ff_layout_mirror *mirror,
+nfs4_ff_layout_stat_io_start_write(struct inode *inode,
+		struct nfs4_ff_layout_mirror *mirror,
 		__u64 requested, ktime_t now)
 {
 	bool report;
···
 	spin_unlock(&mirror->lock);
 
 	if (report)
-		pnfs_report_layoutstat(mirror->lseg->pls_layout->plh_inode,
-				GFP_NOIO);
+		pnfs_report_layoutstat(inode, GFP_NOIO);
 }
 
 static void
···
 static int ff_layout_read_prepare_common(struct rpc_task *task,
 					 struct nfs_pgio_header *hdr)
 {
-	nfs4_ff_layout_stat_io_start_read(
+	nfs4_ff_layout_stat_io_start_read(hdr->inode,
 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
 			hdr->args.count,
 			task->tk_start);
···
 static int ff_layout_write_prepare_common(struct rpc_task *task,
 					  struct nfs_pgio_header *hdr)
 {
-	nfs4_ff_layout_stat_io_start_write(
+	nfs4_ff_layout_stat_io_start_write(hdr->inode,
 			FF_LAYOUT_COMP(hdr->lseg, hdr->pgio_mirror_idx),
 			hdr->args.count,
 			task->tk_start);
···
 static void ff_layout_commit_prepare_common(struct rpc_task *task,
 		struct nfs_commit_data *cdata)
 {
-	nfs4_ff_layout_stat_io_start_write(
+	nfs4_ff_layout_stat_io_start_write(cdata->inode,
 			FF_LAYOUT_COMP(cdata->lseg, cdata->ds_commit_index),
 			0, task->tk_start);
 }
···
 		devinfo->layout_type = LAYOUT_FLEX_FILES;
 		devinfo->layoutstats_encode = ff_layout_encode_layoutstats;
 		devinfo->layout_private = mirror;
-		/* lseg refcount put in cleanup_layoutstats */
-		pnfs_get_lseg(pls);
+		/* mirror refcount put in cleanup_layoutstats */
+		atomic_inc(&mirror->ref);
 
 		++(*dev_count);
 	}
···
 	for (i = 0; i < data->args.num_dev; i++) {
 		mirror = data->args.devinfo[i].layout_private;
 		data->args.devinfo[i].layout_private = NULL;
-		pnfs_put_lseg(mirror->lseg);
+		ff_layout_put_mirror(mirror);
 	}
 }
 

fs/nfs/flexfilelayout/flexfilelayout.h

···
 };
 
 struct nfs4_ff_layout_mirror {
-	struct pnfs_layout_segment	*lseg; /* back pointer */
 	u32				ds_count;
 	u32				efficiency;
 	struct nfs4_ff_layout_ds	*mirror_ds;