[Ocfs2-devel] ocfs2: fix ocfs2 read inode data panic in ocfs2_iget
sunny.s.zhang
sunny.s.zhang at oracle.com
Sun Apr 7 18:18:05 PDT 2019
Hi Gang, Jiang Qi, Joseph,
Can you help me review this patch?
The changes are as follows:
1. Added more detailed descriptions.
2. Used a relatively normal way as suggested by Gang and Joseph.
3. Considering that there may be a slight impact on performance,
I made changes in ocfs2_get_parent, not in ocsf2_iget.
Thanks,
Sunny
在 2019年04月04日 03:00, ocfs2-devel-request at oss.oracle.com 写道:
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> 1. Re: [PATCH v2] ocfs2: fix ocfs2 read inode data panic in
> ocfs2_iget (sunny.s.zhang)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 3 Apr 2019 14:42:50 +0800
> From: "sunny.s.zhang" <sunny.s.zhang at oracle.com>
> Subject: Re: [Ocfs2-devel] [PATCH v2] ocfs2: fix ocfs2 read inode data
> panic in ocfs2_iget
> To: ocfs2-devel at oss.oracle.com
> Message-ID: <2e09a66e-8fbc-2b51-6cce-f2caf8db2828 at oracle.com>
> Content-Type: text/plain; charset=gbk; format=flowed
>
> Hi Friends,
>
> Can someone help me review this patch?
>
> Thanks,
>
> Sunny
>
>
> ? 2019?04?03? 03:00, ocfs2-devel-request at oss.oracle.com ??:
>> Send Ocfs2-devel mailing list submissions to
>> ocfs2-devel at oss.oracle.com
>>
>> To subscribe or unsubscribe via the World Wide Web, visit
>> https://oss.oracle.com/mailman/listinfo/ocfs2-devel
>> or, via email, send a message with subject or body 'help' to
>> ocfs2-devel-request at oss.oracle.com
>>
>> You can reach the person managing the list at
>> ocfs2-devel-owner at oss.oracle.com
>>
>> When replying, please edit your Subject line so it is more specific
>> than "Re: Contents of Ocfs2-devel digest..."
>>
>>
>> Today's Topics:
>>
>> 1. [PATCH v2] ocfs2: fix ocfs2 read inode data panic in
>> ocfs2_iget (Shuning Zhang)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Tue, 2 Apr 2019 14:18:39 +0800
>> From: Shuning Zhang <sunny.s.zhang at oracle.com>
>> Subject: [Ocfs2-devel] [PATCH v2] ocfs2: fix ocfs2 read inode data
>> panic in ocfs2_iget
>> To: ocfs2-devel at oss.oracle.com
>> Message-ID:
>> <1554185919-3010-1-git-send-email-sunny.s.zhang at oracle.com>
>>
>> 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.
>>
>> For example, the ocfs2 is used as the backed of nfs, and the client is
>> nfsv3. This issue can be reproduced 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_dentry)
>>
>> 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. But 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 |
>>
>> [283465.542049] OCFS2: ERROR (device sdp): ocfs2_validate_inode_block:
>> Invalid dinode #580640: OCFS2_VALID_FL not set
>>
>> [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
>>
>> Changes in v2:
>> - add description of reporducing this issue
>> - use ocfs2_test_inode_bit instead of i_dtime
>>
>> Signed-off-by: Shuning Zhang <sunny.s.zhang at oracle.com>
>> ---
>> fs/ocfs2/export.c | 30 +++++++++++++++++++++++++++++-
>> 1 files changed, 29 insertions(+), 1 deletions(-)
>>
>> diff --git a/fs/ocfs2/export.c b/fs/ocfs2/export.c
>> index 827fc98..da17aa6 100644
>> --- a/fs/ocfs2/export.c
>> +++ b/fs/ocfs2/export.c
>> @@ -148,16 +148,24 @@ static struct dentry *ocfs2_get_parent(struct dentry *child)
>> u64 blkno;
>> struct dentry *parent;
>> struct inode *dir = d_inode(child);
>> + int set;
>>
>> trace_ocfs2_get_parent(child, child->d_name.len, child->d_name.name,
>> (unsigned long long)OCFS2_I(dir)->ip_blkno);
>>
>> + status = ocfs2_nfs_sync_lock(OCFS2_SB(dir->i_sb), 1);
>> + if (status < 0) {
>> + mlog(ML_ERROR, "getting nfs sync lock(EX) failed %d\n", status);
>> + parent = ERR_PTR(status);
>> + goto bail;
>> + }
>> +
>> status = ocfs2_inode_lock(dir, NULL, 0);
>> if (status < 0) {
>> if (status != -ENOENT)
>> mlog_errno(status);
>> parent = ERR_PTR(status);
>> - goto bail;
>> + goto unlock_nfs_sync;
>> }
>>
>> status = ocfs2_lookup_ino_from_name(dir, "..", 2, &blkno);
>> @@ -166,11 +174,31 @@ static struct dentry *ocfs2_get_parent(struct dentry *child)
>> goto bail_unlock;
>> }
>>
>> + status = ocfs2_test_inode_bit(OCFS2_SB(dir->i_sb), blkno, &set);
>> + if (status < 0) {
>> + if (status == -EINVAL) {
>> + status = -ESTALE;
>> + } else
>> + mlog(ML_ERROR, "test inode bit failed %d\n", status);
>> + parent = ERR_PTR(status);
>> + goto bail_unlock;
>> + }
>> +
>> + trace_ocfs2_get_dentry_test_bit(status, set);
>> + if (!set) {
>> + status = -ESTALE;
>> + parent = ERR_PTR(status);
>> + goto bail_unlock;
>> + }
>> +
>> parent = d_obtain_alias(ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0, 0));
>>
>> bail_unlock:
>> ocfs2_inode_unlock(dir, 0);
>>
>> +unlock_nfs_sync:
>> + ocfs2_nfs_sync_unlock(OCFS2_SB(dir->i_sb), 1);
>> +
>> bail:
>> trace_ocfs2_get_parent_end(parent);
>>
>
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