Re: [PATCH RFC v2] xfs: Print XFS UUID on mount and umount events.

[lukas@herbolt.com]

> Are you going to wire up fs uuid logging for the other filesystems that
> support them?
Well, I wasn't planning to but I can take a look on other FS as well
Ext4 and Btrfs for start.

> What happens w.r.t. uuid disambiguation if someone uses a nouuid mount
> to mount a filesystem with the same uuid as an already-mounted xfs?

I a not sure I understand the "nouuid mount". I don't think there can
be XFS with empty uuid value in SB. And printing the message is 
independent
on the mount method (mount UUID="" ...; mount /dev/sdX ...;).


On 20.05.2021 17:23, Darrick J. Wong wrote:
> On Wed, May 19, 2021 at 05:22:48PM +0200, Lukas Herbolt wrote:
>> As of now only device names are printed out over __xfs_printk().
>> The device names are not persistent across reboots which in case
>> of searching for origin of corruption brings another task to properly
>> identify the devices. This patch add XFS UUID upon every mount/umount
>> event which will make the identification much easier.
> 
> A few questions....
> 
> Are you going to wire up fs uuid logging for the other filesystems that
> support them?
> 
> What happens w.r.t. uuid disambiguation if someone uses a nouuid mount
> to mount a filesystem with the same uuid as an already-mounted xfs?
> 
> The changes themselves look ok, but I'm wondering what the use case is
> here.
> 
> --D
> 
>> 
>> Signed-off-by: Lukas Herbolt <lukas@herbolt.com>
>> ---
>> V2: Drop void casts and fix long lines
>> 
>>  fs/xfs/xfs_log.c   | 10 ++++++----
>>  fs/xfs/xfs_super.c |  2 +-
>>  2 files changed, 7 insertions(+), 5 deletions(-)
>> 
>> diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
>> index 06041834daa31..8f4f671fd80d5 100644
>> --- a/fs/xfs/xfs_log.c
>> +++ b/fs/xfs/xfs_log.c
>> @@ -570,12 +570,14 @@ xfs_log_mount(
>>  	int		min_logfsbs;
>> 
>>  	if (!(mp->m_flags & XFS_MOUNT_NORECOVERY)) {
>> -		xfs_notice(mp, "Mounting V%d Filesystem",
>> -			   XFS_SB_VERSION_NUM(&mp->m_sb));
>> +		xfs_notice(mp, "Mounting V%d Filesystem %pU",
>> +			   XFS_SB_VERSION_NUM(&mp->m_sb),
>> +			   &mp->m_sb.sb_uuid);
>>  	} else {
>>  		xfs_notice(mp,
>> -"Mounting V%d filesystem in no-recovery mode. Filesystem will be 
>> inconsistent.",
>> -			   XFS_SB_VERSION_NUM(&mp->m_sb));
>> +"Mounting V%d filesystem %pU in no-recovery mode. Filesystem will be 
>> inconsistent.",
>> +			   XFS_SB_VERSION_NUM(&mp->m_sb),
>> +			   &mp->m_sb.sb_uuid);
>>  		ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
>>  	}
>> 
>> diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
>> index e5e0713bebcd8..a4b8a5ad8039f 100644
>> --- a/fs/xfs/xfs_super.c
>> +++ b/fs/xfs/xfs_super.c
>> @@ -1043,7 +1043,7 @@ xfs_fs_put_super(
>>  	if (!sb->s_fs_info)
>>  		return;
>> 
>> -	xfs_notice(mp, "Unmounting Filesystem");
>> +	xfs_notice(mp, "Unmounting Filesystem %pU", &mp->m_sb.sb_uuid);
>>  	xfs_filestream_unmount(mp);
>>  	xfs_unmountfs(mp);
>> 
>> --
>> 2.31.1
>>