diff options
Diffstat (limited to 'init')
| -rw-r--r-- | init/Kconfig | 9 | ||||
| -rw-r--r-- | init/do_mounts.c | 70 |
2 files changed, 76 insertions, 3 deletions
diff --git a/init/Kconfig b/init/Kconfig index be85a0ab1b82..bd125a795374 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -661,11 +661,14 @@ config BLK_CGROUP Currently, CFQ IO scheduler uses it to recognize task groups and control disk bandwidth allocation (proportional time slice allocation) - to such task groups. + to such task groups. It is also used by bio throttling logic in + block layer to implement upper limit in IO rates on a device. This option only enables generic Block IO controller infrastructure. - One needs to also enable actual IO controlling logic in CFQ for it - to take effect. (CONFIG_CFQ_GROUP_IOSCHED=y). + One needs to also enable actual IO controlling logic/policy. For + enabling proportional weight division of disk bandwidth in CFQ seti + CONFIG_CFQ_GROUP_IOSCHED=y and for enabling throttling policy set + CONFIG_BLK_THROTTLE=y. See Documentation/cgroups/blkio-controller.txt for more information. diff --git a/init/do_mounts.c b/init/do_mounts.c index 02e3ca4fc527..42db0551c3aa 100644 --- a/init/do_mounts.c +++ b/init/do_mounts.c @@ -58,6 +58,62 @@ static int __init readwrite(char *str) __setup("ro", readonly); __setup("rw", readwrite); +#ifdef CONFIG_BLOCK +/** + * 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 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; +} +#endif + /* * Convert a name into device number. We accept the following variants: * @@ -68,6 +124,8 @@ __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 +140,18 @@ dev_t name_to_dev_t(char *name) dev_t res = 0; int part; +#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; + goto done; + } +#endif + if (strncmp(name, "/dev/", 5) != 0) { unsigned maj, min; |