UBI: implement multiple volumes rename
Quite useful ioctl which allows to make atomic system upgrades.
The idea belongs to Richard Titmuss <richard_titmuss@logitech.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
index 7c19918..bc8199c 100644
--- a/drivers/mtd/ubi/cdev.c
+++ b/drivers/mtd/ubi/cdev.c
@@ -605,6 +605,166 @@
return 0;
}
+/**
+ * rename_volumes - rename UBI volumes.
+ * @ubi: UBI device description object
+ * @req: volumes re-name request
+ *
+ * This is a helper function for the volume re-name IOCTL which validates the
+ * the request, opens the volume and calls corresponding volumes management
+ * function. Returns zero in case of success and a negative error code in case
+ * of failure.
+ */
+static int rename_volumes(struct ubi_device *ubi,
+ struct ubi_rnvol_req *req)
+{
+ int i, n, err;
+ struct list_head rename_list;
+ struct ubi_rename_entry *re, *re1;
+
+ if (req->count < 0 || req->count > UBI_MAX_RNVOL)
+ return -EINVAL;
+
+ if (req->count == 0)
+ return 0;
+
+ /* Validate volume IDs and names in the request */
+ for (i = 0; i < req->count; i++) {
+ if (req->ents[i].vol_id < 0 ||
+ req->ents[i].vol_id >= ubi->vtbl_slots)
+ return -EINVAL;
+ if (req->ents[i].name_len < 0)
+ return -EINVAL;
+ if (req->ents[i].name_len > UBI_VOL_NAME_MAX)
+ return -ENAMETOOLONG;
+ req->ents[i].name[req->ents[i].name_len] = '\0';
+ n = strlen(req->ents[i].name);
+ if (n != req->ents[i].name_len)
+ err = -EINVAL;
+ }
+
+ /* Make sure volume IDs and names are unique */
+ for (i = 0; i < req->count - 1; i++) {
+ for (n = i + 1; n < req->count; n++) {
+ if (req->ents[i].vol_id == req->ents[n].vol_id) {
+ dbg_err("duplicated volume id %d",
+ req->ents[i].vol_id);
+ return -EINVAL;
+ }
+ if (!strcmp(req->ents[i].name, req->ents[n].name)) {
+ dbg_err("duplicated volume name \"%s\"",
+ req->ents[i].name);
+ return -EINVAL;
+ }
+ }
+ }
+
+ /* Create the re-name list */
+ INIT_LIST_HEAD(&rename_list);
+ for (i = 0; i < req->count; i++) {
+ int vol_id = req->ents[i].vol_id;
+ int name_len = req->ents[i].name_len;
+ const char *name = req->ents[i].name;
+
+ re = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
+ if (!re) {
+ err = -ENOMEM;
+ goto out_free;
+ }
+
+ re->desc = ubi_open_volume(ubi->ubi_num, vol_id, UBI_EXCLUSIVE);
+ if (IS_ERR(re->desc)) {
+ err = PTR_ERR(re->desc);
+ dbg_err("cannot open volume %d, error %d", vol_id, err);
+ kfree(re);
+ goto out_free;
+ }
+
+ /* Skip this re-naming if the name does not really change */
+ if (re->desc->vol->name_len == name_len &&
+ !memcmp(re->desc->vol->name, name, name_len)) {
+ ubi_close_volume(re->desc);
+ kfree(re);
+ continue;
+ }
+
+ re->new_name_len = name_len;
+ memcpy(re->new_name, name, name_len);
+ list_add_tail(&re->list, &rename_list);
+ dbg_msg("will rename volume %d from \"%s\" to \"%s\"",
+ vol_id, re->desc->vol->name, name);
+ }
+
+ if (list_empty(&rename_list))
+ return 0;
+
+ /* Find out the volumes which have to be removed */
+ list_for_each_entry(re, &rename_list, list) {
+ struct ubi_volume_desc *desc;
+ int no_remove_needed = 0;
+
+ /*
+ * Volume @re->vol_id is going to be re-named to
+ * @re->new_name, while its current name is @name. If a volume
+ * with name @re->new_name currently exists, it has to be
+ * removed, unless it is also re-named in the request (@req).
+ */
+ list_for_each_entry(re1, &rename_list, list) {
+ if (re->new_name_len == re1->desc->vol->name_len &&
+ !memcmp(re->new_name, re1->desc->vol->name,
+ re1->desc->vol->name_len)) {
+ no_remove_needed = 1;
+ break;
+ }
+ }
+
+ if (no_remove_needed)
+ continue;
+
+ /*
+ * It seems we need to remove volume with name @re->new_name,
+ * if it exists.
+ */
+ desc = ubi_open_volume_nm(ubi->ubi_num, re->new_name, UBI_EXCLUSIVE);
+ if (IS_ERR(desc)) {
+ err = PTR_ERR(desc);
+ if (err == -ENODEV)
+ /* Re-naming into a non-existing volume name */
+ continue;
+
+ /* The volume exists but busy, or an error occurred */
+ dbg_err("cannot open volume \"%s\", error %d",
+ re->new_name, err);
+ goto out_free;
+ }
+
+ re = kzalloc(sizeof(struct ubi_rename_entry), GFP_KERNEL);
+ if (!re) {
+ err = -ENOMEM;
+ ubi_close_volume(desc);
+ goto out_free;
+ }
+
+ re->remove = 1;
+ re->desc = desc;
+ list_add(&re->list, &rename_list);
+ dbg_msg("will remove volume %d, name \"%s\"",
+ re->desc->vol->vol_id, re->desc->vol->name);
+ }
+
+ mutex_lock(&ubi->volumes_mutex);
+ err = ubi_rename_volumes(ubi, &rename_list);
+ mutex_unlock(&ubi->volumes_mutex);
+
+out_free:
+ list_for_each_entry_safe(re, re1, &rename_list, list) {
+ ubi_close_volume(re->desc);
+ list_del(&re->list);
+ kfree(re);
+ }
+ return err;
+}
+
static int ubi_cdev_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
@@ -670,7 +830,7 @@
}
mutex_lock(&ubi->volumes_mutex);
- err = ubi_remove_volume(desc);
+ err = ubi_remove_volume(desc, 0);
mutex_unlock(&ubi->volumes_mutex);
/*
@@ -717,6 +877,32 @@
break;
}
+ /* Re-name volumes command */
+ case UBI_IOCRNVOL:
+ {
+ struct ubi_rnvol_req *req;
+
+ dbg_msg("re-name volumes");
+ req = kmalloc(sizeof(struct ubi_rnvol_req), GFP_KERNEL);
+ if (!req) {
+ err = -ENOMEM;
+ break;
+ };
+
+ err = copy_from_user(req, argp, sizeof(struct ubi_rnvol_req));
+ if (err) {
+ err = -EFAULT;
+ kfree(req);
+ break;
+ }
+
+ mutex_lock(&ubi->mult_mutex);
+ err = rename_volumes(ubi, req);
+ mutex_unlock(&ubi->mult_mutex);
+ kfree(req);
+ break;
+ }
+
default:
err = -ENOTTY;
break;