[lustre-discuss] llapi_file_open() messages to stderr

[Dilger, Andreas]

It is possible to register an error message handler:

    llapi_log_callback_t llapi_error_callback_set(llapi_log_callback_t cb)
    llapi_log_callback_t llapi_info_callback_set(llapi_log_callback_t cb)

Cheers, Andreas
--
Andreas Dilger
Lustre Principal Architect
Intel High Performance Data Division

On 2016/04/30, 12:44, "lustre-discuss on behalf of John Bauer" <lustre-discuss-bounces at lists.lustre.org<mailto:lustre-discuss-bounces at lists.lustre.org> on behalf of bauerj at iodoctors.com<mailto:bauerj at iodoctors.com>> wrote:


Dennis

Thanks for the response.  There are other reasons I want to suppress these messages.

1) I am trying to minimize system calls.

2) It's kind of overkill for llapi_file_open() to print to stderr.  The function already returns -1 with errno=EEXIST.  Shouldn't it be up to the caller to decide if a message should be printed.

3) There are other messages, different than the stripe already set,  that I also would like to suppress.  Most notably "Invalid argument".  I hate to think that I have to check validity of all the striping arguments to prevent the messages to stderr.  I'll also point that even lfs setstripe doesn't even go to the trouble to tell you which argument is invalid.

    % lfs setstripe -c 486 -i 45 file.dat
    error on ioctl 0x4008669a for 'file.dat' (3): Invalid argument
    error: setstripe: create stripe file 'file.dat' failed
    %

John

On 4/30/2016 12:27 PM, Dennis Nelson wrote:
Check for existing files before making the call?  And don't issue the call if the file exists.  You cannot change stripe attributes on an existing file.

Sent from my iPhone

On Apr 30, 2016, at 11:51 AM, John Bauer <<mailto:bauerj at iodoctors.com>bauerj at iodoctors.com<mailto:bauerj at iodoctors.com>> wrote:


I am implementing the use of llapi_file_open() in my I/O library so I can set the striping.  If the file already exists I get the following message on stderr:

error on ioctl 0x4008669a for 'dd.dat' (4): stripe already set

Is there some way to suppress this message?  The end-uers of my library will get these messages in stderr of their job and will likely have no clue as to why.  My library detects the failed llapi_file_open() and retrys with open64() and spits out its own error message to the library's log.

Thanks

John

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