From 066976b7dbc7e2022efa0244457d804163bc1ee8 Mon Sep 17 00:00:00 2001 From: Samuel Moelius Date: Mon, 3 Aug 2026 14:09:13 +0000 Subject: [PATCH] dm dust: make badblock messages target-relative dm-dust currently treats addbadblock, removebadblock and queryblock arguments as block numbers on the underlying device. That is surprising for a device-mapper target: a dm-dust table with a non-zero backing offset can add bad blocks that are outside the mapped target, and a badblock added for logical block 0 is missed because the I/O path checks the remapped backing-device block instead. Interpret badblock message arguments as blocks relative to the start of the dm-dust target instead. Bound the arguments by the target length and perform badblock lookup using target-relative sectors before remapping the bio to the underlying device. This intentionally changes the non-zero backing-offset behavior to make the badblock control interface match the mapped dm-dust device, rather than the underlying device. Assisted-by: Codex:gpt-5.5-cyber-preview Signed-off-by: Samuel Moelius Tested-by: Bryan Gurney Reviewed-by: Benjamin Marzinski Signed-off-by: Mikulas Patocka --- drivers/md/dm-dust.c | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) diff --git a/drivers/md/dm-dust.c b/drivers/md/dm-dust.c index c7e3077fb1f5..954f4ec5a51c 100644 --- a/drivers/md/dm-dust.c +++ b/drivers/md/dm-dust.c @@ -196,7 +196,6 @@ static int __dust_map_write(struct dust_device *dd, sector_t thisblock) dd->badblock_count--; kfree(bblk); if (!dd->quiet_mode) { - sector_div(thisblock, dd->sect_per_block); DMINFO("block %llu removed from badblocklist by write", (unsigned long long)thisblock); } @@ -224,15 +223,16 @@ static int dust_map_write(struct dust_device *dd, sector_t thisblock, static int dust_map(struct dm_target *ti, struct bio *bio) { struct dust_device *dd = ti->private; + sector_t dust_sector = dm_target_offset(ti, bio->bi_iter.bi_sector); int r; bio_set_dev(bio, dd->dev->bdev); - bio->bi_iter.bi_sector = dd->start + dm_target_offset(ti, bio->bi_iter.bi_sector); + bio->bi_iter.bi_sector = dd->start + dust_sector; if (bio_data_dir(bio) == READ) - r = dust_map_read(dd, bio->bi_iter.bi_sector, dd->fail_read_on_bb); + r = dust_map_read(dd, dust_sector, dd->fail_read_on_bb); else - r = dust_map_write(dd, bio->bi_iter.bi_sector, dd->fail_read_on_bb); + r = dust_map_write(dd, dust_sector, dd->fail_read_on_bb); return r; } @@ -415,7 +415,7 @@ static int dust_message(struct dm_target *ti, unsigned int argc, char **argv, char *result, unsigned int maxlen) { struct dust_device *dd = ti->private; - sector_t size = bdev_nr_sectors(dd->dev->bdev); + sector_t size = dm_sector_div_up(ti->len, dd->sect_per_block); bool invalid_msg = false; int r = -EINVAL; unsigned long long tmp, block; @@ -462,8 +462,7 @@ static int dust_message(struct dm_target *ti, unsigned int argc, char **argv, return r; block = tmp; - sector_div(size, dd->sect_per_block); - if (block > size) { + if (block >= size) { DMERR("selected block value out of range"); return r; } @@ -490,8 +489,7 @@ static int dust_message(struct dm_target *ti, unsigned int argc, char **argv, return r; } wr_fail_cnt = tmp_ui; - sector_div(size, dd->sect_per_block); - if (block > size) { + if (block >= size) { DMERR("selected block value out of range"); return r; }