Re: [PATCH 1/3] NFSD: Added fault injection

[Bryan Schumaker <bjschuma@netapp.com>]

On Fri 28 Oct 2011 05:24:50 PM EDT, J. Bruce Fields wrote:
> On Mon, Oct 24, 2011 at 07:20:57AM -0400, bjschuma@netapp.com wrote:
> ...
>> diff --git a/fs/nfsd/fault_inject.c b/fs/nfsd/fault_inject.c
>> new file mode 100644
>> index 0000000..1ac4134
>> --- /dev/null
>> +++ b/fs/nfsd/fault_inject.c
>> @@ -0,0 +1,90 @@
> ...
>> +int nfsd_fault_inject_init(void)
>> +{
>> +	unsigned int i;
>> +	struct nfsd_fault_inject_op *op;
>> +	mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
>> +
>> +	debug_dir = debugfs_create_dir("nfsd", NULL);
>> +	if (!debug_dir)
>> +		goto fail;
>> +
>> +	for (i = 0; i < NUM_INJECT_OPS; i++) {
>> +		op = &inject_ops[i];
>> +		debugfs_create_file(op->file, mode, debug_dir, op, &fops_nfsd);
>
> I think you need to check the return value and "goto fail" on NULL.

Makes sense.  Thanks for catching that!

>
> (Do you also need to put the returned dentry on success?  Checking other
> callers.... No, I guess not, OK.)
>
>> +	}
>> +	return 0;
>> +
>> +fail:
>> +	nfsd_fault_inject_cleanup();
>> +	return -ENOMEM;
>> +}
> ...
>> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
>> index db34a58..e67f30c 100644
>> --- a/fs/nfsd/nfsctl.c
>> +++ b/fs/nfsd/nfsctl.c
> ...
>> @@ -1130,6 +1131,9 @@ static int __init init_nfsd(void)
>>  	retval = nfs4_state_init(); /* nfs4 locking state */
>>  	if (retval)
>>  		return retval;
>> +	retval = nfsd_fault_inject_init(); /* nfsd fault injection controls */
>> +	if (retval)
>> +		goto out_cleanup_fault_injection;
>>  	nfsd_stat_init();	/* Statistics */
>>  	retval = nfsd_reply_cache_init();
>>  	if (retval)
>> @@ -1161,6 +1165,8 @@ out_free_cache:
>>  out_free_stat:
>>  	nfsd_stat_shutdown();
>>  	nfsd4_free_slabs();
>> +out_cleanup_fault_injection:
>> +	nfsd_fault_inject_cleanup();
>
> Check the cleanup here again....  The slabs are allocated in state_init,
> so you need to do that on nfsd_fault_inject_init, but you *don't* need
> the fault_inject_cleanup in that case, since fault_inject_init cleanup
> cleans up after itself--that's needed only on later failures.

Would it be better to change the fault_inject_init() function so it 
doesn't clean up after itself?  This would keep it consistent with the 
other nfsd init functions.  I didn't realize that slabs were 
initialized in the state_init() function, I'll fix that.

Thanks for the review!

- Bryan
>
> --b.
>
>>  	return retval;
>>  }
>>  
>> @@ -1174,6 +1180,7 @@ static void __exit exit_nfsd(void)
>>  	nfsd_lockd_shutdown();
>>  	nfsd_idmap_shutdown();
>>  	nfsd4_free_slabs();
>> +	nfsd_fault_inject_cleanup();
>>  	unregister_filesystem(&nfsd_fs_type);
>>  }
>>  
>> -- 
>> 1.7.7
>>
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