Eric, As long as lFileNameWithoutTooLongPath length is less than 226 characters and you do not run into some threads related race conditions, that should be just fine, and that roughly covers 99% cases.
Thanks for sharing this workaround ! Cheers, Gilles Eric Chamberland <eric.chamberl...@giref.ulaval.ca> wrote: >Hi! > >Here is a "poor man's fix" that works for me (the idea is not from me, >thanks to Thomas H.): > >#1- char* lCwd = getcwd(0,0); >#2- chdir(lPathToFile); >#3- MPI_File_open(...,lFileNameWithoutTooLongPath,...); >#4- chdir(lCwd); >#5- ... > >I think there are some limitations but it works very well for our >uses... and until a "real" fix is proposed... > >Thanks for helping! > >Eric > > >On 12/15/2014 11:42 PM, Gilles Gouaillardet wrote: >> Eric and all, >> >> That is clearly a limitation in romio, and this is being tracked at >> https://trac.mpich.org/projects/mpich/ticket/2212 >> >> in the mean time, what we can do in OpenMPI is update >> mca_io_romio_file_open() and fails with a user friendly error message >> if strlen(filename) is larger that 225. >> >> Cheers, >> >> Gilles >> >> On 2014/12/16 12:43, Gilles Gouaillardet wrote: >>> Eric, >>> >>> thanks for the simple test program. >>> >>> i think i see what is going wrong and i will make some changes to avoid >>> the memory overflow. >>> >>> that being said, there is a hard coded limit of 256 characters, and your >>> path is bigger than 300 characters. >>> bottom line, and even if there is no more memory overflow, that cannot >>> work as expected. >>> >>> i will report this to the mpich folks, since romio is currently imported >>> from mpich. >>> >>> Cheers, >>> >>> Gilles >>> >>> On 2014/12/16 0:16, Eric Chamberland wrote: >>>> Hi Gilles, >>>> >>>> just created a very simple test case! >>>> >>>> with this setup, you will see the bug with valgrind: >>>> >>>> export >>>> too_long=./this/is/a_very/long/path/that/contains/a/not/so/long/filename/but/trying/to/collectively/mpi_file_open/it/you/will/have/a/memory/corruption/resulting/of/invalide/writing/or/reading/past/the/end/of/one/or/some/hidden/strings/in/mpio/Simple/user/would/like/to/have/the/parameter/checked/and/an/error/returned/or/this/limit/removed >>>> >>>> mpicc -o bug_MPI_File_open_path_too_long >>>> bug_MPI_File_open_path_too_long.c >>>> >>>> mkdir -p $too_long >>>> echo "header of a text file" > $too_long/toto.txt >>>> >>>> mpirun -np 2 valgrind ./bug_MPI_File_open_path_too_long >>>> $too_long/toto.txt >>>> >>>> and watch the errors! >>>> >>>> unfortunately, the memory corruptions here doesn't seem to segfault >>>> this simple test case, but in my case, it is fatal and with valgrind, >>>> it is reported... >>>> >>>> OpenMPI 1.6.5, 1.8.3rc3 are affected >>>> >>>> MPICH-3.1.3 also have the error! >>>> >>>> thanks, >>>> >>>> Eric >>>> >>> _______________________________________________ >>> users mailing list >>> us...@open-mpi.org >>> Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users >>> Link to this post: >>> http://www.open-mpi.org/community/lists/users/2014/12/26005.php >> _______________________________________________ >> users mailing list >> us...@open-mpi.org >> Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users >> Link to this post: >> http://www.open-mpi.org/community/lists/users/2014/12/26006.php > >_______________________________________________ >users mailing list >us...@open-mpi.org >Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users >Link to this post: >http://www.open-mpi.org/community/lists/users/2014/12/26022.php
