fs/overlayfs/export.c

36  * Before encoding a non-upper directory file handle from real layer N, we need
37  * to check if it will be possible to reconnect an overlay dentry from the real
172  * (*) Decoding a connected overlay dir from real lower dentry is not always
292  * Find or instantiate an overlay dentry from real dentries and index.
353  * Lookup a child overlay dentry to get a connected overlay dentry whose real
354  * dentry is @real. If @real is on upper layer, we lookup a child overlay
355  * dentry with the same name as the real dentry. Otherwise, we need to consult
359 					  struct dentry *real,
368 	 * Lookup child overlay dentry by real name. The dir mutex protects us
370 	 * real has already been moved to a parent that is not under the
372 	 * connected real path from the top.
376 	parent = dget_parent(real);
381 	 * We also need to take a snapshot of real dentry name to protect us
384 	 * pointer because we hold no lock on the real dentry.
386 	take_dentry_name_snapshot(&name, real);
399 	} else if (ovl_dentry_real_at(this, layer->idx) != real) {
411 	pr_warn_ratelimited("failed to lookup one by real (%pd2, layer=%d, connected=%pd2, err=%i)\n",
412 			    real, layer->idx, connected, err);
418 				      struct dentry *real,
422  * Lookup an indexed or hashed overlay dentry by real inode.
425 					    struct dentry *real,
437 	inode = ovl_lookup_inode(sb, real, !layer->idx);
449 	if (!this && layer->idx && ovl_indexdir(sb) && !WARN_ON(!d_is_dir(real))) {
450 		index = ovl_lookup_index(ofs, NULL, real, false);
477 	if (ovl_dentry_real_at(this, layer->idx) != real) {
486  * Lookup an indexed or hashed overlay dentry, whose real dentry is an
487  * ancestor of @real.
490 					       struct dentry *real,
496 	if (real == layer->mnt->mnt_root)
500 	next = dget(real);
506 		 * cache or in index by real inode.
518 		 * If @real has been moved out of the layer root directory,
519 		 * we will eventully hit the real fs root. This cannot happen
538  * Lookup a connected overlay dentry whose real dentry is @real.
539  * If @real is on upper layer, we lookup a child overlay dentry with the same
540  * path the real dentry. Otherwise, we need to consult index for lookup.
543 				      struct dentry *real,
549 	connected = ovl_lookup_real_ancestor(sb, real, layer);
559 		if (real_connected == real)
563 		next = dget(real);
571 			 * If real has been moved out of 'real_connected',
585 			 * If real file has been moved out of the layer root
586 			 * directory, we will eventully hit the real fs root.
609 			 * still an ancestor of 'real'. There is a good chance
615 				this = ovl_lookup_real_ancestor(sb, real,
635 	pr_warn_ratelimited("failed to lookup by real (%pd2, layer=%d, connected=%pd2, err=%i)\n",
636 			    real, layer->idx, connected, err);
642  * Get an overlay dentry from upper/lower real dentries and index.
651 	struct dentry *real = upper ?: (index ?: lowerpath->dentry);
654 	 * Obtain a disconnected overlay dentry from a non-dir real dentry
657 	if (!d_is_dir(real))
661 	if ((real->d_flags & DCACHE_DISCONNECTED) || d_unhashed(real))
665 	 * If real dentry is connected and hashed, get a connected overlay
666 	 * dentry whose real dentry is @real.
668 	return ovl_lookup_real(sb, real, layer);