Hi When running the lvm testsuite, we get a lot of warnings "blk_update_request: operation not supported error, dev loop0, sector 0 op 0x9:(WRITE_ZEROES) flags 0x800800 phys_seg 0 prio class 0". The lvm testsuite puts the loop device on tmpfs and the reason for the warning is that tmpfs supports fallocate, but doesn't support FALLOC_FL_ZERO_RANGE. I've created this patch to silence the warnings. Mikulas From: Mikulas Patocka <mpatocka@xxxxxxxxxx> The loop driver checks for the fallocate method and if it is present, it assumes that the filesystem can do FALLOC_FL_ZERO_RANGE and FALLOC_FL_PUNCH_HOLE requests. However, some filesystems (such as fat, or tmpfs) have the fallocate method, but lack the capability to do FALLOC_FL_ZERO_RANGE and/or FALLOC_FL_PUNCH_HOLE. This results in syslog warnings "blk_update_request: operation not supported error, dev loop0, sector 0 op 0x9:(WRITE_ZEROES) flags 0x800800 phys_seg 0 prio class 0" This patch sets RQF_QUIET to silence the warnings. Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx --- drivers/block/loop.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) Index: linux-2.6/drivers/block/loop.c =================================================================== --- linux-2.6.orig/drivers/block/loop.c 2021-09-23 17:06:57.000000000 +0200 +++ linux-2.6/drivers/block/loop.c 2021-09-23 21:29:39.000000000 +0200 @@ -493,7 +493,16 @@ static int lo_fallocate(struct loop_devi ret = file->f_op->fallocate(file, mode, pos, blk_rq_bytes(rq)); if (unlikely(ret && ret != -EINVAL && ret != -EOPNOTSUPP)) ret = -EIO; - out: +out: + + /* + * Some filesystems have the fallocate method, but lack the capability + * to do FALLOC_FL_ZERO_RANGE and/or FALLOC_FL_PUNCH_HOLE requests. + * We do not want a syslog warning in this case. + */ + if (ret == -EOPNOTSUPP) + rq->rq_flags |= RQF_QUIET; + return ret; }
