fs/overlayfs/super.c

399 	 * file handles, so they require that all layers support them.
488 		pr_err("upper fs is r/o, try multi-lower layers mount\n");
912 		 * as all lower layers with null uuid are on the same fs.
973  * The fsid after the last lower fsid is used for the data layers.
983 			  struct ovl_fs_context *ctx, struct ovl_layer *layers)
995 	 * and the last fsid is reserved for "null fs" of the data layers.
1000 	 * All lower layers that share the same fs as upper layer, use the same
1031 		 * Check if lower root conflicts with this overlay layers before
1058 		 * Make lower layers R/O.  That way fchmod/fchown on lower file
1063 		layers[ofs->numlayer].trap = trap;
1064 		layers[ofs->numlayer].mnt = mnt;
1065 		layers[ofs->numlayer].idx = ofs->numlayer;
1066 		layers[ofs->numlayer].fsid = fsid;
1067 		layers[ofs->numlayer].fs = &ofs->fs[fsid];
1076 	 * When all layers on same fs, overlay can use real inode numbers.
1086 			pr_info("\"xino=on\" is useless with all layers on same fs, ignore.\n");
1113 					    struct ovl_layer *layers)
1144 	err = ovl_get_layers(sb, ofs, ctx, layers);
1149 	/* Data-only layers are not merged in root directory */
1159 		lowerstack[i].layer = &ofs->layers[i + 1];
1202  * Check if any of the layers or work dirs overlap.
1230 				      ofs->layers[i].mnt->mnt_root,
1298 	struct ovl_layer *layers;
1325 	layers = kcalloc(ctx->nr + 1, sizeof(struct ovl_layer), GFP_KERNEL);
1326 	if (!layers)
1331 		kfree(layers);
1334 	ofs->layers = layers;
1368 		err = ovl_get_upper(sb, ofs, &layers[0], &ctx->upper);
1392 	oe = ovl_get_lowerstack(sb, ctx, ofs, layers);
1440 	 * if all layers support file handles.