2 /* AFS cell alias detection
17 static struct afs_volume *afs_sample_volume(struct afs_cell *cell, struct key *key,  in afs_sample_volume()  argument
25 		.net		= cell->net,  in afs_sample_volume()
26 		.cell		= cell,  in afs_sample_volume()
105  * Compare root.cell volumes.
107 static int afs_compare_cell_roots(struct afs_cell *cell)  in afs_compare_cell_roots()  argument
115 	hlist_for_each_entry_rcu(p, &cell->net->proc_cells, proc_link) {  in afs_compare_cell_roots()
116 		if (p == cell || p->alias_of)  in afs_compare_cell_roots()
119 			continue; /* Ignore cells that don't have a root.cell volume. */  in afs_compare_cell_roots()
121 		if (afs_compare_volume_slists(cell->root_volume, p->root_volume) != 0)  in afs_compare_cell_roots()
131 	cell->alias_of = afs_use_cell(p, afs_cell_trace_use_alias);  in afs_compare_cell_roots()
136  * Query the new cell for a volume from a cell we're already using.
138 static int afs_query_for_alias_one(struct afs_cell *cell, struct key *key,  in afs_query_for_alias_one()  argument
154 	_enter("%s:%s", cell->name, pvol->name);  in afs_query_for_alias_one()
156 	/* And see if it's in the new cell. */  in afs_query_for_alias_one()
157 	volume = afs_sample_volume(cell, key, pvol->name, pvol->name_len);  in afs_query_for_alias_one()
162 		/* That volume is not in the new cell, so not an alias */  in afs_query_for_alias_one()
166 	/* The new cell has a like-named volume also - compare volume ID,  in afs_query_for_alias_one()
183  * Query the new cell for volumes we know exist in cells we're already using.
185 static int afs_query_for_alias(struct afs_cell *cell, struct key *key)  in afs_query_for_alias()  argument
189 	_enter("%s", cell->name);  in afs_query_for_alias()
191 	if (mutex_lock_interruptible(&cell->net->proc_cells_lock) < 0)  in afs_query_for_alias()
194 	hlist_for_each_entry(p, &cell->net->proc_cells, proc_link) {  in afs_query_for_alias()
195 		if (p == cell || p->alias_of)  in afs_query_for_alias()
200 			continue; /* Ignore cells that have a root.cell volume. */  in afs_query_for_alias()
202 		mutex_unlock(&cell->net->proc_cells_lock);  in afs_query_for_alias()
204 		if (afs_query_for_alias_one(cell, key, p) != 0)  in afs_query_for_alias()
207 		if (mutex_lock_interruptible(&cell->net->proc_cells_lock) < 0) {  in afs_query_for_alias()
208 			afs_unuse_cell(cell->net, p, afs_cell_trace_unuse_check_alias);  in afs_query_for_alias()
212 		afs_unuse_cell(cell->net, p, afs_cell_trace_unuse_check_alias);  in afs_query_for_alias()
215 	mutex_unlock(&cell->net->proc_cells_lock);  in afs_query_for_alias()
220 	cell->alias_of = p; /* Transfer our ref */  in afs_query_for_alias()
227 static char *afs_vl_get_cell_name(struct afs_cell *cell, struct key *key)  in afs_vl_get_cell_name()  argument
234 	if (!afs_begin_vlserver_operation(&vc, cell, key))  in afs_vl_get_cell_name()
253 static int yfs_check_canonical_cell_name(struct afs_cell *cell, struct key *key)  in yfs_check_canonical_cell_name()  argument
258 	cell_name = afs_vl_get_cell_name(cell, key);  in yfs_check_canonical_cell_name()
262 	if (strcmp(cell_name, cell->name) == 0) {  in yfs_check_canonical_cell_name()
267 	master = afs_lookup_cell(cell->net, cell_name, strlen(cell_name),  in yfs_check_canonical_cell_name()
273 	cell->alias_of = master; /* Transfer our ref */  in yfs_check_canonical_cell_name()
277 static int afs_do_cell_detect_alias(struct afs_cell *cell, struct key *key)  in afs_do_cell_detect_alias()  argument
282 	_enter("%s", cell->name);  in afs_do_cell_detect_alias()
284 	ret = yfs_check_canonical_cell_name(cell, key);  in afs_do_cell_detect_alias()
288 	/* Try and get the root.cell volume for comparison with other cells */  in afs_do_cell_detect_alias()
289 	root_volume = afs_sample_volume(cell, key, "root.cell", 9);  in afs_do_cell_detect_alias()
291 		cell->root_volume = root_volume;  in afs_do_cell_detect_alias()
292 		return afs_compare_cell_roots(cell);  in afs_do_cell_detect_alias()
298 	/* Okay, this cell doesn't have an root.cell volume.  We need to  in afs_do_cell_detect_alias()
301 	return afs_query_for_alias(cell, key);  in afs_do_cell_detect_alias()
305  * Check to see if a new cell is an alias of a cell we already have.  At this
306  * point we have the cell's volume server list.
310  * detect an alias, cell->alias_of is set to point to the assumed master.
312 int afs_cell_detect_alias(struct afs_cell *cell, struct key *key)  in afs_cell_detect_alias()  argument
314 	struct afs_net *net = cell->net;  in afs_cell_detect_alias()
320 	if (test_bit(AFS_CELL_FL_CHECK_ALIAS, &cell->flags)) {  in afs_cell_detect_alias()
321 		ret = afs_do_cell_detect_alias(cell, key);  in afs_cell_detect_alias()
323 			clear_bit_unlock(AFS_CELL_FL_CHECK_ALIAS, &cell->flags);  in afs_cell_detect_alias()
325 		ret = cell->alias_of ? 1 : 0;  in afs_cell_detect_alias()
331 		pr_notice("kAFS: Cell %s is an alias of %s\n",  in afs_cell_detect_alias()
332 			  cell->name, cell->alias_of->name);  in afs_cell_detect_alias()