diff options
| author | Nikolaus Voss <nikolaus.voss@loewensteinmedical.de> | 2018-10-30 15:05:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-10-31 08:54:13 -0700 |
| commit | f027c34d844013d9d6c902af8fa01a82d6e5073d (patch) | |
| tree | 46d4851a2f48ad45fb064ddd30c30c36362059cc | |
| parent | 22ebb72b32606aa0f891e09de007be7d3d8effd1 (diff) | |
init/do_mounts.c: add root=PARTLABEL=<name> support
Support referencing the root partition label from GPT as argument
to the root= option on the kernel command line in analogy to
referencing the partition uuid as root=PARTUUID=<uuid>.
Specifying the partition label instead of the uuid is often much
easier, e.g. in embedded environments when there is an
A/B rootfs partition scheme for interruptible firmware updates
(i.e. rootfsA/ rootfsB).
The partition label can be queried with the blkid command.
Link: http://lkml.kernel.org/r/20180822060904.828E510665E@pc-niv.weinmann.com
Signed-off-by: Nikolaus Voss <nikolaus.voss@loewensteinmedical.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Sasha Levin <Alexander.Levin@microsoft.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | init/do_mounts.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/init/do_mounts.c b/init/do_mounts.c index e1c9afa9d8c9..a754e3ba9831 100644 --- a/init/do_mounts.c +++ b/init/do_mounts.c @@ -167,6 +167,24 @@ done: } return res; } + +/** + * match_dev_by_label - callback for finding a partition using its label + * @dev: device passed in by the caller + * @data: opaque pointer to the label to match + * + * Returns 1 if the device matches, and 0 otherwise. + */ +static int match_dev_by_label(struct device *dev, const void *data) +{ + const char *label = data; + struct hd_struct *part = dev_to_part(dev); + + if (part->info && !strcmp(label, part->info->volname)) + return 1; + + return 0; +} #endif /* @@ -190,6 +208,8 @@ done: * a partition with a known unique id. * 8) <major>:<minor> major and minor number of the device separated by * a colon. + * 9) PARTLABEL=<name> with name being the GPT partition label. + * MSDOS partitions do not support labels! * * 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 @@ -211,6 +231,17 @@ dev_t name_to_dev_t(const char *name) if (!res) goto fail; goto done; + } else if (strncmp(name, "PARTLABEL=", 10) == 0) { + struct device *dev; + + dev = class_find_device(&block_class, NULL, name + 10, + &match_dev_by_label); + if (!dev) + goto fail; + + res = dev->devt; + put_device(dev); + goto done; } #endif |