From c2affe920b0e0669650943ac086215cf6519be34 Mon Sep 17 00:00:00 2001
From: Adrian Huang <ahuang12@lenovo.com>
Date: Wed, 19 Aug 2020 23:42:36 +0800
Subject: [PATCH] dax: do not print error message for non-persistent memory
block device
Git-commit: c2affe920b0e0669650943ac086215cf6519be34
Patch-mainline: v5.9-rc3
References: bsc#1171073
Commit 231609785cbf ("dax: print error message by pr_info()
in __generic_fsdax_supported()") happens to print the following
error message during booting when the non-persistent memory block
devices are configured by device mapper. Those error messages are
caused by the variable 'dax_dev' is NULL. Users might be confused
with those error messages since they do not use the persistent
memory device. Moreover, users might scare about "what's wrong
with my disks" because they see the 'error' and 'failed' keywords.
# dmesg | grep fail
sdk3: error: dax access failed (-95)
sdk3: error: dax access failed (-95)
sdk3: error: dax access failed (-95)
sdk3: error: dax access failed (-95)
sdk3: error: dax access failed (-95)
sdk3: error: dax access failed (-95)
sdk3: error: dax access failed (-95)
sdk3: error: dax access failed (-95)
sdk3: error: dax access failed (-95)
sdb3: error: dax access failed (-95)
sdb3: error: dax access failed (-95)
sdb3: error: dax access failed (-95)
sdb3: error: dax access failed (-95)
sdb3: error: dax access failed (-95)
sdb3: error: dax access failed (-95)
sdb3: error: dax access failed (-95)
sdb3: error: dax access failed (-95)
sdb3: error: dax access failed (-95)
# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 1.1T 0 disk
├─sda1 8:1 0 156M 0 part
├─sda2 8:2 0 40G 0 part
└─sda3 8:3 0 1.1T 0 part
sdb 8:16 0 1.1T 0 disk
├─sdb1 8:17 0 600M 0 part
├─sdb2 8:18 0 1G 0 part
└─sdb3 8:19 0 1.1T 0 part
├─rhel00-swap 254:3 0 4G 0 lvm
├─rhel00-home 254:4 0 1T 0 lvm
└─rhel00-root 254:5 0 50G 0 lvm
sdc 8:32 0 1.1T 0 disk
sdd 8:48 0 1.1T 0 disk
sde 8:64 0 1.1T 0 disk
sdf 8:80 0 1.1T 0 disk
sdg 8:96 0 1.1T 0 disk
sdh 8:112 0 3.3T 0 disk
├─sdh1 8:113 0 500M 0 part /boot/efi
├─sdh2 8:114 0 40G 0 part /
├─sdh3 8:115 0 2.9T 0 part /home
└─sdh4 8:116 0 314.6G 0 part [SWAP]
sdi 8:128 0 1.1T 0 disk
sdj 8:144 0 3.3T 0 disk
├─sdj1 8:145 0 512M 0 part
└─sdj2 8:146 0 3.3T 0 part
sdk 8:160 0 119.2G 0 disk
├─sdk1 8:161 0 200M 0 part
├─sdk2 8:162 0 1G 0 part
└─sdk3 8:163 0 118G 0 part
├─rhel-swap 254:0 0 4G 0 lvm
├─rhel-home 254:1 0 64G 0 lvm
└─rhel-root 254:2 0 50G 0 lvm
sdl 8:176 0 119.2G 0 disk
The call path is shown as follows:
dm_table_determine_type
dm_table_supports_dax
device_supports_dax
generic_fsdax_supported
__generic_fsdax_supported
With the disk configuration listing from the command 'lsblk',
the member 'dev->dax_dev' of the block devices 'sdb3' and 'sdk3'
(configured by device mapper) is NULL in function
generic_fsdax_supported() because the member is configured in
function open_table_device().
To prevent the confusing error messages in this scenario (this is
normal behavior), just print those error messages by pr_debug()
by checking if dax_dev is NULL and the block device does not support
DAX.
Link: https://lore.kernel.org/r/20200819154236.24191-1-adrianhuang0701@gmail.com
Fixes: 231609785cbf ("dax: print error message by pr_info() in __generic_fsdax_supported()")
Cc: Coly Li <colyli@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Acked-by: Coly Li <colyli@suse.de>
Signed-off-by: Adrian Huang <ahuang12@lenovo.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
drivers/dax/super.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index c82cbcb64202..32642634c1bb 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -100,6 +100,12 @@ bool __generic_fsdax_supported(struct dax_device *dax_dev,
return false;
}
+ if (!dax_dev && !bdev_dax_supported(bdev, blocksize)) {
+ pr_debug("%s: error: dax unsupported by block device\n",
+ bdevname(bdev, buf));
+ return false;
+ }
+
id = dax_read_lock();
len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn);
len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn);
--
2.26.2