This is a preparation for the next patch, which changes blk_set_default_limits() to set 0 for max_sectors/max_hw_sectors. With the next patch, for dm targets like 'zero', where there's no underlying device, those values remain 0 and the dm device becomes unusable. So check the max_sectors and set to SAFE_MAX_SECTORS if 0. Check this thread for further background: https://www.redhat.com/archives/dm-devel/2009-September/msg00176.html Signed-off-by: Kiyoshi Ueda <k-ueda@xxxxxxxxxxxxx> Signed-off-by: Jun'ichi Nomura <j-nomura@xxxxxxxxxxxxx> Cc: David Strand <dpstrand@xxxxxxxxx> Cc: Mike Snitzer <snitzer@xxxxxxxxxx> Cc: Alasdair G Kergon <agk@xxxxxxxxxx> Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Cc: Jens Axboe <jens.axboe@xxxxxxxxxx> --- drivers/md/dm-table.c | 11 +++++++++++ 1 file changed, 11 insertions(+) Index: linux-2.6.31.work/drivers/md/dm-table.c =================================================================== --- linux-2.6.31.work.orig/drivers/md/dm-table.c +++ linux-2.6.31.work/drivers/md/dm-table.c @@ -707,6 +707,17 @@ static int validate_hardware_logical_blo device_logical_block_size_sects - next_target_start : 0; } + /* + * blk_set_default_limits() sets max_sectors/max_hw_sectors to 0. + * When all targets have no underlying device, they are + * left unchanged from the default values and cause problems. + * Use SAFE_MAX_SECTORS for such cases. + */ + if (limits->max_hw_sectors == 0) + limits->max_hw_sectors = SAFE_MAX_SECTORS; + if (limits->max_sectors == 0) + limits->max_sectors = SAFE_MAX_SECTORS; + if (remaining) { DMWARN("%s: table line %u (start sect %llu len %llu) " "not aligned to h/w logical block size %u", -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
