storage: deprecate lxc.rootfs.backend

src/lxc/bdev/bdev.c

@@ -187,11 +187,11 @@ struct bdev_type {
 };
 
 static const struct bdev_type bdevs[] = {
+	{ .name = "dir",       .ops = &dir_ops,   },
 	{ .name = "zfs",       .ops = &zfs_ops,   },
 	{ .name = "lvm",       .ops = &lvm_ops,   },
 	{ .name = "rbd",       .ops = &rbd_ops,   },
 	{ .name = "btrfs",     .ops = &btrfs_ops, },
-	{ .name = "dir",       .ops = &dir_ops,   },
 	{ .name = "aufs",      .ops = &aufs_ops,  },
 	{ .name = "overlayfs", .ops = &ovl_ops,   },
 	{ .name = "loop",      .ops = &loop_ops,  },
@@ -890,40 +890,41 @@ static struct bdev *bdev_get(const char *type)
 
 static const struct bdev_type *get_bdev_by_name(const char *name)
 {
-	size_t i;
+	size_t i, cmplen;
 
-	for (i = 0; i < numbdevs; i++) {
-		if (strcmp(bdevs[i].name, name) == 0)
-			return &bdevs[i];
-	}
+	cmplen = strcspn(name, ":");
+	if (cmplen == 0)
+		return NULL;
 
-	ERROR("Backing store %s unknown but not caught earlier\n", name);
-	return NULL;
+	for (i = 0; i < numbdevs; i++)
+		if (strncmp(bdevs[i].name, name, cmplen) == 0)
+			break;
+
+	if (i == numbdevs)
+		return NULL;
+
+	DEBUG("Detected rootfs type \"%s\"", bdevs[i].name);
+	return &bdevs[i];
 }
 
 static const struct bdev_type *bdev_query(struct lxc_conf *conf,
 					  const char *src)
 {
 	size_t i;
+	const struct bdev_type *bdev;
 
-	if (conf->rootfs.bdev_type) {
-		DEBUG("config file specified rootfs type \"%s\"",
-		      conf->rootfs.bdev_type);
-		return get_bdev_by_name(conf->rootfs.bdev_type);
-	}
+	bdev = get_bdev_by_name(src);
+	if (bdev)
+		return bdev;
 
-	for (i = 0; i < numbdevs; i++) {
-		int r;
-		r = bdevs[i].ops->detect(src);
-		if (r)
+	for (i = 0; i < numbdevs; i++)
+		if (bdevs[i].ops->detect(src))
 			break;
-	}
 
 	if (i == numbdevs)
 		return NULL;
 
-	DEBUG("detected rootfs type \"%s\"", bdevs[i].name);
-
+	DEBUG("Detected rootfs type \"%s\"", bdevs[i].name);
 	return &bdevs[i];
 }
 

src/lxc/bdev/lxcaufs.c

@@ -229,8 +229,9 @@ int aufs_destroy(struct bdev *orig)
 
 int aufs_detect(const char *path)
 {
-	if (strncmp(path, "aufs:", 5) == 0)
-		return 1; // take their word for it
+	if (!strncmp(path, "aufs:", 5))
+		return 1;
+
 	return 0;
 }
 

src/lxc/bdev/lxcbtrfs.c

@@ -174,10 +174,13 @@ int btrfs_detect(const char *path)
 	struct stat st;
 	int ret;
 
+	if (!strncmp(path, "btrfs:", 6))
+		return 1;
+
 	if (!is_btrfs_fs(path))
 		return 0;
 
-	// and make sure it's a subvolume.
+	/* make sure it's a subvolume */
 	ret = stat(path, &st);
 	if (ret < 0)
 		return 0;

src/lxc/bdev/lxcdir.c

@@ -96,8 +96,9 @@ int dir_destroy(struct bdev *orig)
 
 int dir_detect(const char *path)
 {
-	if (strncmp(path, "dir:", 4) == 0)
-		return 1; // take their word for it
+	if (!strncmp(path, "dir:", 4))
+		return 1;
+
 	if (is_dir(path))
 		return 1;
 	return 0;

src/lxc/bdev/lxcloop.c

@@ -161,7 +161,7 @@ int loop_detect(const char *path)
 	int ret;
 	struct stat s;
 
-	if (strncmp(path, "loop:", 5) == 0)
+	if (!strncmp(path, "loop:", 5))
 		return 1;
 
 	ret = stat(path, &s);

src/lxc/bdev/lxclvm.c

@@ -134,8 +134,8 @@ int lvm_detect(const char *path)
 	int ret;
 	struct stat statbuf;
 
-	if (strncmp(path, "lvm:", 4) == 0)
-		return 1; // take their word for it
+	if (!strncmp(path, "lvm:", 4))
+		return 1;
 
 	ret = stat(path, &statbuf);
 	if (ret != 0)

src/lxc/bdev/lxcnbd.c

@@ -107,8 +107,9 @@ int nbd_destroy(struct bdev *orig)
 
 int nbd_detect(const char *path)
 {
-	if (strncmp(path, "nbd:", 4) == 0)
+	if (!strncmp(path, "nbd:", 4))
 		return 1;
+
 	return 0;
 }
 

src/lxc/bdev/lxcoverlay.c

@@ -298,8 +298,12 @@ int ovl_destroy(struct bdev *orig)
 
 int ovl_detect(const char *path)
 {
-	if (strncmp(path, "overlayfs:", 10) == 0)
-		return 1; // take their word for it
+	if (!strncmp(path, "overlayfs:", 10))
+		return 1;
+
+	if (!strncmp(path, "overlay:", 8))
+		return 1;
+
 	return 0;
 }
 

src/lxc/bdev/lxcrbd.c

@@ -154,8 +154,12 @@ int rbd_destroy(struct bdev *orig)
 
 int rbd_detect(const char *path)
 {
-	if ( memcmp(path, "/dev/rbd/", 9) == 0)
+	if (!strncmp(path, "rbd:", 4))
 		return 1;
+
+	if (!strncmp(path, "/dev/rbd/", 9))
+		return 1;
+
 	return 0;
 }
 

src/lxc/bdev/lxczfs.c

@@ -70,6 +70,9 @@ int zfs_list_entry(const char *path, char *output, size_t inlen)
 
 int zfs_detect(const char *path)
 {
+	if (!strncmp(path, "zfs:", 4))
+		return 1;
+
 	char *output = malloc(LXC_LOG_BUFFER_SIZE);
 
 	if (!output) {

src/lxc/confile.c

@@ -162,7 +162,12 @@ static struct lxc_config_t config[] = {
 	{ "lxc.mount",                     set_config_fstab,	                   get_config_fstab,                       clr_config_fstab,                     },
 	{ "lxc.rootfs.mount",              set_config_rootfs_mount,                get_config_rootfs_mount,                clr_config_rootfs_mount,              },
 	{ "lxc.rootfs.options",            set_config_rootfs_options,              get_config_rootfs_options,              clr_config_rootfs_options,            },
+
+	/* REMOVE IN LXC 3.0
+	   legacy rootfs.backend key
+	 */
 	{ "lxc.rootfs.backend",            set_config_rootfs_backend,              get_config_rootfs_backend,              clr_config_rootfs_backend,            },
+
 	{ "lxc.rootfs",                    set_config_rootfs,                      get_config_rootfs,                      clr_config_rootfs,                    },
 
 	/* REMOVE IN LXC 3.0
@@ -2051,18 +2056,7 @@ static int set_config_rootfs_options(const char *key, const char *value,
 static int set_config_rootfs_backend(const char *key, const char *value,
 				     struct lxc_conf *lxc_conf, void *data)
 {
-	if (lxc_config_value_empty(value)) {
-		free(lxc_conf->rootfs.bdev_type);
-		lxc_conf->rootfs.bdev_type = NULL;
-		return 0;
-	}
-
-	if (!is_valid_bdev_type(value)) {
-		ERROR("Bad rootfs.backend: '%s'", value);
-		return -1;
-	}
-
-	return set_config_string_item(&lxc_conf->rootfs.bdev_type, value);
+	return 0;
 }
 
 static int set_config_uts_name(const char *key, const char *value,
@@ -3053,7 +3047,7 @@ static int get_config_rootfs_options(const char *key, char *retv, int inlen,
 static int get_config_rootfs_backend(const char *key, char *retv, int inlen,
 				     struct lxc_conf *c, void *data)
 {
-	return lxc_get_conf_str(retv, inlen, c->rootfs.bdev_type);
+	return 0;
 }
 
 static int get_config_uts_name(const char *key, char *retv, int inlen,
@@ -3473,8 +3467,6 @@ static inline int clr_config_rootfs_options(const char *key, struct lxc_conf *c,
 static inline int clr_config_rootfs_backend(const char *key, struct lxc_conf *c,
 					    void *data)
 {
-	free(c->rootfs.bdev_type);
-	c->rootfs.bdev_type = NULL;
 	return 0;
 }
 

src/lxc/lxccontainer.c

@@ -1043,7 +1043,7 @@ static bool create_container_dir(struct lxc_container *c)
  * it returns a mounted bdev on success, NULL on error.
  */
 static struct bdev *do_bdev_create(struct lxc_container *c, const char *type,
-			 struct bdev_specs *specs)
+				   struct bdev_specs *specs)
 {
 	char *dest;
 	size_t len;
@@ -1051,7 +1051,7 @@ static struct bdev *do_bdev_create(struct lxc_container *c, const char *type,
 	int ret;
 
 	/* rootfs.path or lxcpath/lxcname/rootfs */
-	if (c->lxc_conf->rootfs.path && access(c->lxc_conf->rootfs.path, F_OK) == 0) {
+	if (c->lxc_conf->rootfs.path && !access(c->lxc_conf->rootfs.path, F_OK)) {
 		const char *rpath = c->lxc_conf->rootfs.path;
 		len = strlen(rpath) + 1;
 		dest = alloca(len);
@@ -1071,12 +1071,15 @@ static struct bdev *do_bdev_create(struct lxc_container *c, const char *type,
 		return NULL;
 	}
 
-	do_lxcapi_set_config_item(c, "lxc.rootfs", bdev->src);
-	do_lxcapi_set_config_item(c, "lxc.rootfs.backend", bdev->type);
-
-	/* if we are not root, chown the rootfs dir to root in the
-	 * target uidmap */
+	if (!c->set_config_item(c, "lxc.rootfs", bdev->src)) {
+		ERROR("Failed to set config item \"lxc.rootfs\" to \"%s\"",
+		      bdev->src);
+		return NULL;
+	}
 
+	/* If we are not root, chown the rootfs dir to root in the
+	 * target uidmap.
+	 */
 	if (geteuid() != 0 || (c->lxc_conf && !lxc_list_empty(&c->lxc_conf->id_map))) {
 		if (chown_mapped_root(bdev->dest, c->lxc_conf) < 0) {
 			ERROR("Error chowning %s to container root", bdev->dest);
@@ -2924,20 +2927,12 @@ static int copy_storage(struct lxc_container *c0, struct lxc_container *c,
 	/* Set new rootfs. */
 	free(c->lxc_conf->rootfs.path);
 	c->lxc_conf->rootfs.path = strdup(bdev->src);
-
-	/* Set new bdev type. */
-	free(c->lxc_conf->rootfs.bdev_type);
-	c->lxc_conf->rootfs.bdev_type = strdup(bdev->type);
 	bdev_put(bdev);
 
 	if (!c->lxc_conf->rootfs.path) {
 		ERROR("Out of memory while setting storage path.");
 		return -1;
 	}
-	if (!c->lxc_conf->rootfs.bdev_type) {
-		ERROR("Out of memory while setting rootfs backend.");
-		return -1;
-	}
 
 	/* Append a new lxc.rootfs entry to the unexpanded config. */
 	clear_unexp_config_line(c->lxc_conf, "lxc.rootfs", false);
@@ -2949,11 +2944,6 @@ static int copy_storage(struct lxc_container *c0, struct lxc_container *c,
 
 	/* Append a new lxc.rootfs.backend entry to the unexpanded config. */
 	clear_unexp_config_line(c->lxc_conf, "lxc.rootfs.backend", false);
-	if (!do_append_unexp_config_line(c->lxc_conf, "lxc.rootfs.backend",
-					 c->lxc_conf->rootfs.bdev_type)) {
-		ERROR("Error saving new rootfs backend to cloned config.");
-		return -1;
-	}
 
 	if (flags & LXC_CLONE_SNAPSHOT)
 		copy_rdepends(c, c0);