| Message ID | 20250403003532.412-1-chanho.min@lge.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | block: remove non-existent partition dev_t return from blk_lookup_devt | expand |
diff --git a/block/early-lookup.c b/block/early-lookup.c index 3fb57f7d2b127..3764dfb429c54 100644 --- a/block/early-lookup.c +++ b/block/early-lookup.c @@ -134,17 +134,9 @@ static dev_t __init blk_lookup_devt(const char *name, int partno) if (strcmp(dev_name(dev), name)) continue; - if (partno < disk->minors) { - /* We need to return the right devno, even - * if the partition doesn't exist yet. - */ - devt = MKDEV(MAJOR(dev->devt), - MINOR(dev->devt) + partno); - } else { - devt = part_devt(disk, partno); - if (devt) - break; - } + devt = part_devt(disk, partno); + if (devt) + break; } class_dev_iter_exit(&iter); return devt;
We encountered frequent boot failures while setting up a dm-verity rootfs with the following configuration, and found that this issue had been reported previously: root=/dev/dm-0 dm-mod.waitfor=/dev/mmcblk0p23 The error observed was: device-mapper: table: 254:0: verity: Data device lookup failed (-ENXIO) device-mapper: ioctl: error adding target to table Bisecting the issue revealed that this was a latent problem exacerbated by commit 238d991f054a ("dm: use fsleep() instead of msleep() for deterministic sleep duration"), after which the failures became more frequent. Further investigation pinpointed the root cause to a special case added in blk_lookup_devt() by commit 41b8c853a495 ("block: fix booting from partitioned md array") This commit modified blk_lookup_devt() to return a dev_t for non-existent partitions to support MD RAID booting when partitions are not yet available, e.g., for root=/dev/md_d0p1. While this addressed the MD issue, it deviates from the expected role of blk_lookup_devt(), which should return a dev_t only for existing block devices. Adding MD-specific logic to a common block layer function was a suboptimal approach, as it compromises the function's clarity and causes side effects, such as the dm-init failures seen with dm-verity. The MD RAID booting issue should ideally have been handled within the MD driver or boot logic (e.g., via a dedicated md_lookup_devt() function) rather than modifying a generic lookup function. This patch removes the non-existent partition dev_t return logic, restoring blk_lookup_devt() to its intended purpose. This resolves the dm-verity boot failures by ensuring accurate dev_t returns. If MD RAID booting still depends on this behavior in some setups, a regression may occur. In that case, the MD subsystem should implement a proper solution (e.g., specific lookup function) rather than relying on this workaround. Testers are encouraged to verify MD RAID booting with partitioned root devices (e.g., root=/dev/md_d0p1) to confirm. Signed-off-by: Chanho Min <chanho.min@lge.com> --- block/early-lookup.c | 14 +++----------- 1 file changed, 3 insertions(+), 11 deletions(-)