int root_mountflags = MS_RDONLY | MS_SILENT;
static char * __initdata root_device_name;
static char __initdata saved_root_name[64];
-static int __initdata root_wait;
+static int root_wait;
dev_t ROOT_DEV;
/**
* devt_from_partuuid - looks up the dev_t of a partition by its UUID
- * @uuid: 36 byte char array containing a hex ascii UUID
+ * @uuid: min 36 byte char array containing a hex ascii UUID
*
* The function will return the first partition which contains a matching
* UUID value in its partition_meta_info struct. This does not search
* by filesystem UUIDs.
*
+ * If @uuid is followed by a "/PARTNROFF=%d", then the number will be
+ * extracted and used as an offset from the partition identified by the UUID.
+ *
* Returns the matching dev_t on success or 0 on failure.
*/
static dev_t devt_from_partuuid(char *uuid_str)
dev_t res = 0;
struct device *dev = NULL;
u8 uuid[16];
+ struct gendisk *disk;
+ struct hd_struct *part;
+ int offset = 0;
+
+ if (strlen(uuid_str) < 36)
+ goto done;
+
+ /* Check for optional partition number offset attributes. */
+ if (uuid_str[36]) {
+ char c = 0;
+ /* Explicitly fail on poor PARTUUID syntax. */
+ if (sscanf(&uuid_str[36],
+ "/PARTNROFF=%d%c", &offset, &c) != 1) {
+ printk(KERN_ERR "VFS: PARTUUID= is invalid.\n"
+ "Expected PARTUUID=<valid-uuid-id>[/PARTNROFF=%%d]\n");
+ if (root_wait)
+ printk(KERN_ERR
+ "Disabling rootwait; root= is invalid.\n");
+ root_wait = 0;
+ goto done;
+ }
+ }
/* Pack the requested UUID in the expected format. */
part_pack_uuid(uuid_str, uuid);
goto done;
res = dev->devt;
- put_device(dev);
+ /* Attempt to find the partition by offset. */
+ if (!offset)
+ goto no_offset;
+
+ res = 0;
+ disk = part_to_disk(dev_to_part(dev));
+ part = disk_get_part(disk, dev_to_part(dev)->partno + offset);
+ if (part) {
+ res = part_devt(part);
+ put_device(part_to_dev(part));
+ }
+
+no_offset:
+ put_device(dev);
done:
return res;
}
* used when disk name of partitioned disk ends on a digit.
* 6) PARTUUID=00112233-4455-6677-8899-AABBCCDDEEFF representing the
* unique id of a partition if the partition table provides it.
+ * 7) PARTUUID=<UUID>/PARTNROFF=<int> to select a partition in relation to
+ * a partition with a known unique id.
*
* If name doesn't have fall into the categories above, we return (0,0).
* block_class is used to check if something is a disk name. If the disk
#ifdef CONFIG_BLOCK
if (strncmp(name, "PARTUUID=", 9) == 0) {
name += 9;
- if (strlen(name) != 36)
- goto fail;
res = devt_from_partuuid(name);
if (!res)
goto fail;
}
#ifdef CONFIG_ROOT_NFS
+
+#define NFSROOT_TIMEOUT_MIN 5
+#define NFSROOT_TIMEOUT_MAX 30
+#define NFSROOT_RETRY_MAX 5
+
static int __init mount_nfs_root(void)
{
char *root_dev, *root_data;
+ unsigned int timeout;
+ int try, err;
- if (nfs_root_data(&root_dev, &root_data) != 0)
+ err = nfs_root_data(&root_dev, &root_data);
+ if (err != 0)
return 0;
- if (do_mount_root(root_dev, "nfs", root_mountflags, root_data) != 0)
- return 0;
- return 1;
+
+ /*
+ * The server or network may not be ready, so try several
+ * times. Stop after a few tries in case the client wants
+ * to fall back to other boot methods.
+ */
+ timeout = NFSROOT_TIMEOUT_MIN;
+ for (try = 1; ; try++) {
+ err = do_mount_root(root_dev, "nfs",
+ root_mountflags, root_data);
+ if (err == 0)
+ return 1;
+ if (try > NFSROOT_RETRY_MAX)
+ break;
+
+ /* Wait, in case the server refused us immediately */
+ ssleep(timeout);
+ timeout <<= 1;
+ if (timeout > NFSROOT_TIMEOUT_MAX)
+ timeout = NFSROOT_TIMEOUT_MAX;
+ }
+ return 0;
}
#endif