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-rw-r--r--init/do_mounts.c66
1 files changed, 66 insertions, 0 deletions
diff --git a/init/do_mounts.c b/init/do_mounts.c
index 02e3ca4fc52..804f9c6ba21 100644
--- a/init/do_mounts.c
+++ b/init/do_mounts.c
@@ -58,6 +58,60 @@ static int __init readwrite(char *str)
__setup("ro", readonly);
__setup("rw", readwrite);
+/**
+ * match_dev_by_uuid - callback for finding a partition using its uuid
+ * @dev: device passed in by the caller
+ * @data: opaque pointer to a 36 byte char array with a UUID
+ *
+ * Returns 1 if the device matches, and 0 otherwise.
+ */
+static int __init match_dev_by_uuid(struct device *dev, void *data)
+{
+ u8 *uuid = data;
+ struct hd_struct *part = dev_to_part(dev);
+
+ if (!part->info)
+ goto no_match;
+
+ if (memcmp(uuid, part->info->uuid, sizeof(part->info->uuid)))
+ goto no_match;
+
+ return 1;
+no_match:
+ return 0;
+}
+
+
+/**
+ * devt_from_partuuid - looks up the dev_t of a partition by its UUID
+ * @uuid: 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.
+ *
+ * Returns the matching dev_t on success or 0 on failure.
+ */
+static dev_t __init devt_from_partuuid(char *uuid_str)
+{
+ dev_t res = 0;
+ struct device *dev = NULL;
+ u8 uuid[16];
+
+ /* Pack the requested UUID in the expected format. */
+ part_pack_uuid(uuid_str, uuid);
+
+ dev = class_find_device(&block_class, NULL, uuid, &match_dev_by_uuid);
+ if (!dev)
+ goto done;
+
+ res = dev->devt;
+ put_device(dev);
+
+done:
+ return res;
+}
+
/*
* Convert a name into device number. We accept the following variants:
*
@@ -68,6 +122,8 @@ __setup("rw", readwrite);
* of partition - device number of disk plus the partition number
* 5) /dev/<disk_name>p<decimal> - same as the above, that form is
* 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.
*
* 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
@@ -82,6 +138,16 @@ dev_t name_to_dev_t(char *name)
dev_t res = 0;
int part;
+ if (strncmp(name, "PARTUUID=", 9) == 0) {
+ name += 9;
+ if (strlen(name) != 36)
+ goto fail;
+ res = devt_from_partuuid(name);
+ if (!res)
+ goto fail;
+ goto done;
+ }
+
if (strncmp(name, "/dev/", 5) != 0) {
unsigned maj, min;