Date:   Fri, 18 Mar 2022 18:14:46 +0800
From:   zhanchengbin <zhanchengbin1@...wei.com>
To:     Theodore Ts'o <tytso@....edu>
CC:     <linux-ext4@...r.kernel.org>, linfeilong <linfeilong@...wei.com>,
        <liuzhiqiang26@...wei.com>
Subject: Re: e2fsck: do not skip deeper checkers when s_last_orphan list has
 truncated inodes



在 2022/3/16 1:54, Theodore Ts'o 写道:
> On Tue, Mar 15, 2022 at 04:01:45PM +0800, zhanchengbin wrote:
>> If the system crashes when a file is being truncated, we will get a
>> problematic inode,
>> and it will be added into fs->super->s_last_orphan.
>> When we run `e2fsck -a img`, the s_last_orphan list will be traversed and
>> deleted.
>> During this period, orphan inodes in the s_last_orphan list with
>> i_links_count==0 can
>> be deleted, and orphan inodes with  i_links_count !=0 (ex. the truncated
>> inode)
>> cannot be deleted. However, when there are some orphan inodes with
>> i_links_count !=0,
>> the EXT2_VALID_FS is still assigned to fs->super->s_state, the deeper
>> checkers are skipped
>> with some inconsistency problems.
> 
> That's not supposed to happen.  We regularly put inodes on the orphan
> list when they are being truncated so that if we crash, the truncation
> operation can be completed as part of the journal recovery and remount
> operation.  This is true regardles sof whether the recovery is done by
> e2fsck or by the kernel.

Yes, you are right.
Truncated has been completed，and file ACL has been set to zero in
release_inode_blocks(), but the i_blocks was not subtracted acl blocks.
So i_blocks is inconsistent。
Li Jinlin sent a patch yesterday to fix it.

> 
> If a crash during a truncate leads to an inconsistent file system
> after the file system is mounted, or after e2fsck does the journal
> replay and orphan inode list processing, that's a kernel bug, and we
> should fix the bug in the kernel.
> 
> Do you have a reliable reproducer for this situation?

I have a reproducer but it is not necessarily:
#!/bin/bash
disk_list=$(multipath -ll | grep filedisk | awk '{print $1}')

for disk in ${disk_list}
do
     mkfs.ext4 -F /dev/mapper/$disk
     mkdir ${disk}
done

function err_inject()
{
     iscsiadm -m node -p 127.0.0.1 -u &> /dev/null
     iscsiadm -m node -p 127.0.0.1 -l &> /dev/null
     sleep 1
     iscsiadm -m node -p 9.82.236.206 -u &> /dev/null
     iscsiadm -m node -p 9.82.236.206 -l &> /dev/null
     sleep 1

     iscsiadm -m node -p 127.0.0.1 -u &> /dev/null
     iscsiadm -m node -p 127.0.0.1 -l &> /dev/null
     iscsiadm -m node -p 9.82.236.206 -u &> /dev/null
     iscsiadm -m node -p 9.82.236.206 -l &> /dev/null
     sleep 1
}



count=0
while true
do
     ((count=count+1))
     for disk in ${disk_list}
     do
         while true
         do
             mount -o data_err=abort,errors=remount-ro /dev/mapper/$disk 
$disk && break
             sleep 0.1
         done
         nohup fsstress -d $(pwd)/$disk -l 10 -n 1000 -p 10 &>/dev/null &
     done

     sleep 5

     for disk in ${disk_list}
     do
         dm=$(multipath -ll | grep -w $disk | awk '{print $2}')
         aqu_sz=$(iostat -x 1 -d 2 | grep -w $dm | tail -1 | awk '{print 
$(NF-1)}')
         util=$(iostat -x 1 -d 2 | grep -w $dm | tail -1 | awk '{print 
$NF}')
         #if [ "${aqu_sz}" == "0.00" -o "$util" == "0.00" ];then
         #    iostat -x 1 -d 2
         #    exit 1
         #fi
         mount | grep $disk | grep '(ro' && exit 1
     done

     err_inject

     while [ -n "`pidof fsstress`" ]
     do
         sleep 1
     done

     for disk in ${disk_list}
     do
         umount $disk
         dm=$(multipath -ll | grep -w $disk | awk '{print $2}')
         aqu_sz=$(iostat -x 1 -d 2 | grep -w $dm | tail -1 | awk '{print 
$(NF-1)}')
         util=$(iostat -x 1 -d 2 | grep -w $dm | tail -1 | awk '{print 
$NF}')
         if [ "${aqu_sz}" != "0.00" -o "$util" != "0.00" ];then
             iostat -x 1 -d 2
             exit 1
         fi

         dd bs=1M if=/dev/mapper/$disk of=/root/dockerback

         fsck.ext4 -a /dev/mapper/$disk
             ret=$?
             if [ $ret -ne 0 -a $ret -ne 1 ]; then
                 exit 1
             fi

         fsck.ext4 -fn /dev/mapper/$disk
             ret=$?
             if [ $ret -ne 0 ]; then
                 exit 1
             fi
     done

     if [ $count -gt 5 ];then
         echo 3 > /proc/sys/vm/drop_caches
         sleep 1
         cat /proc/meminfo >> mem.txt
         echo "" >> mem.txt
         slabtop -o >> slab.txt
         echo "" >> slab.txt
         count=0
     fi
done

> 
> Thanks,
> 
> 						- Ted
> .
> 

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