Commit 6dfdf536 authored by David Howells's avatar David Howells
Browse files

afs: Detect cell aliases 3 - YFS Cells with a canonical cell name op 



YFS Volume Location servers have an operation by which the cell name may be
queried.  Use this to find out what a YFS server thinks the canonical cell
name should be.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
parent 6ef350b1

fs/afs/vl_alias.c

+58 −0
Original line number Diff line number Diff line
@@ -268,12 +268,70 @@ static int afs_query_for_alias(struct afs_cell *cell, struct key *key) 
	return 1;

}



/*

 * Look up a VLDB record for a volume.

 */

static char *afs_vl_get_cell_name(struct afs_cell *cell, struct key *key)

{

	struct afs_vl_cursor vc;

	char *cell_name = ERR_PTR(-EDESTADDRREQ);

	bool skipped = false, not_skipped = false;

	int ret;



	if (!afs_begin_vlserver_operation(&vc, cell, key))

		return ERR_PTR(-ERESTARTSYS);



	while (afs_select_vlserver(&vc)) {

		if (!test_bit(AFS_VLSERVER_FL_IS_YFS, &vc.server->flags)) {

			vc.ac.error = -EOPNOTSUPP;

			skipped = true;

			continue;

		}

		not_skipped = true;

		cell_name = afs_yfsvl_get_cell_name(&vc);

	}



	ret = afs_end_vlserver_operation(&vc);

	if (skipped && !not_skipped)

		ret = -EOPNOTSUPP;

	return ret < 0 ? ERR_PTR(ret) : cell_name;

}



static int yfs_check_canonical_cell_name(struct afs_cell *cell, struct key *key)

{

	struct afs_cell *master;

	char *cell_name;



	cell_name = afs_vl_get_cell_name(cell, key);

	if (IS_ERR(cell_name))

		return PTR_ERR(cell_name);



	if (strcmp(cell_name, cell->name) == 0) {

		kfree(cell_name);

		return 0;

	}



	master = afs_lookup_cell(cell->net, cell_name, strlen(cell_name),

				 NULL, false);

	kfree(cell_name);

	if (IS_ERR(master))

		return PTR_ERR(master);



	cell->alias_of = master; /* Transfer our ref */

	return 1;

}



static int afs_do_cell_detect_alias(struct afs_cell *cell, struct key *key)

{

	struct afs_volume *root_volume;

	int ret;



	_enter("%s", cell->name);



	ret = yfs_check_canonical_cell_name(cell, key);

	if (ret != -EOPNOTSUPP)

		return ret;



	/* Try and get the root.cell volume for comparison with other cells */

	root_volume = afs_sample_volume(cell, key, "root.cell", 9);

	if (!IS_ERR(root_volume)) {

fs/afs/vl_rotate.c

+4 −0
Original line number Diff line number Diff line
@@ -151,6 +151,10 @@ bool afs_select_vlserver(struct afs_vl_cursor *vc) 
		vc->error = error;

		vc->flags |= AFS_VL_CURSOR_RETRY;

		goto next_server;



	case -EOPNOTSUPP:

		_debug("notsupp");

		goto next_server;

	}



restart_from_beginning: