[Ocfs2-devel] [PATCH] ocfs2: fix ocfs2 read inode data panic in ocfs2_iget
sunny.s.zhang
sunny.s.zhang at oracle.com
Thu Mar 28 18:05:00 PDT 2019
Hi Gang, Jiang Qi, Joseph,
Is my description clear?
Are there any other suggestions?
In addition, it works fine on ext4.
在 2019年03月25日 14:15, sunny.s.zhang 写道:
> Hi Gang,
>
>
> 在 2019年03月25日 11:11, Gang He 写道:
>> Hi Sunny,
>>
>>
>>>>> On 2019/3/25 at 10:18, in message
>> <ab0a6ca7-2f6a-b738-72ce-4ffb6787aad2 at oracle.com>, "sunny.s.zhang"
>> <sunny.s.zhang at oracle.com> wrote:
>>
>>> 在 2019年03月25日 09:31, Joseph Qi 写道:
>>>> On 19/3/25 09:26, Shuning Zhang wrote:
>>>>> In some cases, the function ocfs2_iget read the data of inode,
>>>>> which has
>>>>> been deleted for some reason. That will make the system panic. So We
>>>>> should judge whether this inode has been deleted, and tell the caller
>>>>> that the inode is a bad inode.
>>>>>
>>>>> [283465.542049] OCFS2: ERROR (device sdp):
>>>>> ocfs2_validate_inode_block:
>>>>> Invalid dinode #580640: OCFS2_VALID_FL not set
>>>>>
>>>> Looks like it is a filesystem corruption bug.
>>>> So we'd better find where it is introduced and try to fix it there.
>>> Thank you for reviewing
>>> In that case, the ocfs2 was used as rear end of NFS(V3), which is
>>> stateless as we know. NFS can't protect parent
>>> directory from being deleted, when child is being accessed. We can find
>>> the description at Documentation/filesystems/nfs/Exporting.
>>> I have reproduced this issue by adding some delay codes. This issue
>>> can
>>> be reproduced in the production environment in case of heavy load .
>>> Of course this is a defect of NFS(V3), But I think ocfs2 should have
>>> some fault tolerance. ocfs2 should not panic, if it try to get a
>>> nonexistent inode.
>> I feel ocfs2_test_inode_bit() can avoid the problem, but why do we
>> still encounter this problem?
>> Maybe there are some potential logic(or race condition) problem.
> ocfs2_test_inode_bit() can test whether the inode have been deleted,
> but can't avoid this issue.
> The key of this issue is ocfs2_get_parent() calls ocfs2_iget(inode) ,
> but does not check if the inode exists.
> I think this issue alse can be fixed, If ocfs2_get_parent() call
> ocfs2_test_inode_bit before calling ocfs2_iget().
> But this will have a little impact on performance.
>
> This issue can be reproduce by the following steps.
> on the nfs server side,
> ..../patha/pathb
>
> Step 1: The process A was scheduled before calling the function
> fh_verify.
>
> Step 2: The process B is removing the 'pathb', and just completed the
> call to
> function dput.
> Then the dentry of 'pathb' has been deleted from the dcache, and all
> ancestors have been deleted also.
> The relationship of dentry and inode was deleted through the function
> hlist_del_init. The following is the call stack.
> dentry_iput->hlist_del_init(&dentry->d_u.d_alias)
>
> At this time, the inode is still in the dcache.
>
> Step 3: The process A call the function ocfs2_get_dentry, which get
> the inode
> from dcache. Then the refcount of inode is 1. The following is the call
> stack.
> nfsd3_proc_getacl->fh_verify->exportfs_decode_fh->fh_to_dentry(ocfs2_get_dentr
>
> y)
>
> Step 4: Dirty pages are flushed by bdi threads. So the inode of
> 'patha' is
> evicted, and this directory was deleted.
> But the inode of 'pathb' can't be evicted, because the refcount of the
> inode
> was 1.
>
> Step 5: The process A keep running, and call the function
> reconnect_path(in exportfs_decode_fh),
> which call function ocfs2_get_parent of ocfs2. Get the block number of
> parent
> directory(patha) by the name of "..". Then read the data from disk by the
> block number. Bug this inode has been deleted, so the system panic.
>
>
> Process A Process B
> 1. in nfsd3_proc_getacl |
> 2. | dput
> 3. fh_to_dentry(ocfs2_get_dentry) |
> 4. bdi flush dirty cache |
> 5. ocfs2_iget |
>
> Thanks,
> Sunny
>> Thanks
>> Gang
>>
>>
>>> Thanks,
>>> Sunny
>>>> Thanks,
>>>> Joseph
>>>>
>>>>> [283465.545490] Kernel panic - not syncing: OCFS2: (device sdp):
>>>>> panic
>>> forced
>>>>> after error
>>>>>
>>>>> [283465.546889] CPU: 5 PID: 12416 Comm: nfsd Tainted: G W
>>>>> 4.1.12-124.18.6.el6uek.bug28762940v3.x86_64 #2
>>>>> [283465.548382] Hardware name: VMware, Inc. VMware Virtual
>>>>> Platform/440BX
>>>>> Desktop Reference Platform, BIOS 6.00 09/21/2015
>>>>> [283465.549657] 0000000000000000 ffff8800a56fb7b8 ffffffff816e839c
>>>>> ffffffffa0514758
>>>>> [283465.550392] 000000000008dc20 ffff8800a56fb838 ffffffff816e62d3
>>>>> 0000000000000008
>>>>> [283465.551056] ffff880000000010 ffff8800a56fb848 ffff8800a56fb7e8
>>>>> ffff88005df9f000
>>>>> [283465.551710] Call Trace:
>>>>> [283465.552516] [<ffffffff816e839c>] dump_stack+0x63/0x81
>>>>> [283465.553291] [<ffffffff816e62d3>] panic+0xcb/0x21b
>>>>> [283465.554037] [<ffffffffa04e66b0>] ocfs2_handle_error+0xf0/0xf0
>>>>> [ocfs2]
>>>>> [283465.554882] [<ffffffffa04e7737>] __ocfs2_error+0x67/0x70 [ocfs2]
>>>>> [283465.555768] [<ffffffffa049c0f9>]
>>>>> ocfs2_validate_inode_block+0x229/0x230
>>>>> [ocfs2]
>>>>> [283465.556683] [<ffffffffa047bcbc>]
>>>>> ocfs2_read_blocks+0x46c/0x7b0 [ocfs2]
>>>>> [283465.557408] [<ffffffffa049bed0>] ?
>>>>> ocfs2_inode_cache_io_unlock+0x20/0x20
>>>>> [ocfs2]
>>>>> [283465.557973] [<ffffffffa049f0eb>]
>>>>> ocfs2_read_inode_block_full+0x3b/0x60
>>>>> [ocfs2]
>>>>> [283465.558525] [<ffffffffa049f5ba>] ocfs2_iget+0x4aa/0x880 [ocfs2]
>>>>> [283465.559082] [<ffffffffa049146e>] ocfs2_get_parent+0x9e/0x220
>>>>> [ocfs2]
>>>>> [283465.559622] [<ffffffff81297c05>] reconnect_path+0xb5/0x300
>>>>> [283465.560156] [<ffffffff81297f46>] exportfs_decode_fh+0xf6/0x2b0
>>>>> [283465.560708] [<ffffffffa062faf0>] ?
>>>>> nfsd_proc_getattr+0xa0/0xa0 [nfsd]
>>>>> [283465.561262] [<ffffffff810a8196>] ? prepare_creds+0x26/0x110
>>>>> [283465.561932] [<ffffffffa0630860>] fh_verify+0x350/0x660 [nfsd]
>>>>> [283465.562862] [<ffffffffa0637804>] ?
>>>>> nfsd_cache_lookup+0x44/0x630 [nfsd]
>>>>> [283465.563697] [<ffffffffa063a8b9>] nfsd3_proc_getattr+0x69/0xf0
>>>>> [nfsd]
>>>>> [283465.564510] [<ffffffffa062cf60>] nfsd_dispatch+0xe0/0x290 [nfsd]
>>>>> [283465.565358] [<ffffffffa05eb892>] ?
>>>>> svc_tcp_adjust_wspace+0x12/0x30
>>>>> [sunrpc]
>>>>> [283465.566272] [<ffffffffa05ea652>]
>>>>> svc_process_common+0x412/0x6a0 [sunrpc]
>>>>> [283465.567155] [<ffffffffa05eaa03>] svc_process+0x123/0x210
>>>>> [sunrpc]
>>>>> [283465.568020] [<ffffffffa062c90f>] nfsd+0xff/0x170 [nfsd]
>>>>> [283465.568962] [<ffffffffa062c810>] ? nfsd_destroy+0x80/0x80 [nfsd]
>>>>> [283465.570112] [<ffffffff810a622b>] kthread+0xcb/0xf0
>>>>> [283465.571099] [<ffffffff810a6160>] ?
>>>>> kthread_create_on_node+0x180/0x180
>>>>> [283465.572114] [<ffffffff816f11b8>] ret_from_fork+0x58/0x90
>>>>> [283465.573156] [<ffffffff810a6160>] ?
>>>>> kthread_create_on_node+0x180/0x180
>>>>> ---
>>>>> fs/ocfs2/inode.c | 22 ++++++++++++++++++++++
>>>>> 1 files changed, 22 insertions(+), 0 deletions(-)
>>>>>
>>>>> diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
>>>>> index b254416..a7f8160 100644
>>>>> --- a/fs/ocfs2/inode.c
>>>>> +++ b/fs/ocfs2/inode.c
>>>>> @@ -513,6 +513,16 @@ static int ocfs2_read_locked_inode(struct
>>>>> inode *inode,
>>>>> status = -EINVAL;
>>>>> fe = (struct ocfs2_dinode *) bh->b_data;
>>>>> + /*
>>>>> + * In some cases, this inode has been deleted, but the data of
>>>>> + * inode is read directly. So We should judge whether this inode
>>>>> + * has been deleted.
>>>>> + * */
>>>>> + if (unlikely(fe->i_dtime != 0)) {
>>>>> + mlog(ML_NOTICE, "The inode %llu has been deleted\n",
>>>>> + le64_to_cpu(fe->i_blkno));
>>>>> + goto bail;
>>>>> + }
>>>>> /*
>>>>> * This is a code bug. Right now the caller needs to
>>>>> * understand whether it is asking for a system file inode or
>>>>> @@ -1331,6 +1341,18 @@ int ocfs2_validate_inode_block(struct
>>>>> super_block
>>> *sb,
>>>>> BUG_ON(!buffer_uptodate(bh));
>>>>> + /*
>>>>> + * In some cases, this inode has been deleted, but the data of
>>>>> + * inode is read directly. This is not a data corruption.So
>>>>> + * We should judge whether this inode has been deleted.
>>>>> + * */
>>>>> + if (unlikely(di->i_dtime != 0)) {
>>>>> + rc = -EINVAL;
>>>>> + mlog(ML_NOTICE, "The inode %llu has been deleted\n",
>>>>> + le64_to_cpu(di->i_blkno));
>>>>> + goto bail;
>>>>> + }
>>>>> +
>>>>> /*
>>>>> * If the ecc fails, we return the error but otherwise
>>>>> * leave the filesystem running. We know any error is
>>>>>
>>>
>>> _______________________________________________
>>> Ocfs2-devel mailing list
>>> Ocfs2-devel at oss.oracle.com
>>> https://oss.oracle.com/mailman/listinfo/ocfs2-devel
>
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