rules: Handle MMC boot partitions by-path correctly (#6026)

Many eMMC devices have separate boot partitions that aren't part of the
normal partition table that show up as /dev/mmcblk[0-9]boot[0-9]. These
partitions are generally small (128KB to 16MB) and typically hold a boot
loader, boot loader data or a recovery image. Match these and create
-boot%n by-path symlinks.

Prior to this change by-path symlinks for the main device would be
incorrectly linked to one of the boot partitions.

For instance before:
/dev/disk/by-path/platform-219c000.usdhc linked to /dev/mmcblk1boot1

Now:
/dev/disk/by-path/platform-219c000.usdhc links to /dev/mmcblk1
/dev/disk/by-path/platform-219c000.usdhc-boot0 links to /dev/mmcblk1boot0
/dev/disk/by-path/platform-219c000.usdhc-boot1 links to /dev/mmcblk1boot1

On systems that support multiple SD/MMC devices it can be essential to
have by-path links to these devices since device names vary depending on
which other devices are connected.

1 files changed, 2 insertions, 1 deletions

diff --git a/rules/60-persistent-storage.rules b/rules/60-persistent-storage.rules
index 9817e9c64b..d2745f65f4 100644
--- a/rules/60-persistent-storage.rules
+++ b/rules/60-persistent-storage.rules
@@ -64,7 +64,8 @@ KERNEL=="msblk[0-9]p[0-9]|mspblk[0-9]p[0-9]", ENV{ID_NAME}=="?*", ENV{ID_SERIAL}
 
 # by-path
 ENV{DEVTYPE}=="disk", DEVPATH!="*/virtual/*", IMPORT{builtin}="path_id"
-ENV{DEVTYPE}=="disk", ENV{ID_PATH}=="?*", SYMLINK+="disk/by-path/$env{ID_PATH}"
+KERNEL=="mmcblk[0-9]boot[0-9]", ENV{DEVTYPE}=="disk", ENV{ID_PATH}=="?*", SYMLINK+="disk/by-path/$env{ID_PATH}-boot%n"
+KERNEL!="mmcblk[0-9]boot[0-9]", ENV{DEVTYPE}=="disk", ENV{ID_PATH}=="?*", SYMLINK+="disk/by-path/$env{ID_PATH}"
 ENV{DEVTYPE}=="partition", ENV{ID_PATH}=="?*", SYMLINK+="disk/by-path/$env{ID_PATH}-part%n"
 
 # legacy virtio-pci by-path links (deprecated)