Re: [Gluster-devel] [PATCH v7] vfs_glusterfs: Samba VFS module for glusterfs

[Anand Avati]

On Tue, May 28, 2013 at 4:47 PM, Anand Avati <address@hidden> wrote:

On 05/28/2013 03:42 PM, Anand Avati wrote:

On Tue, May 28, 2013 at 2:46 PM, Andrew Bartlett <address@hidden

<mailto:address@hidden>> wrote:

    On Tue, 2013-05-28 at 17:36 -0400, Anand Avati wrote:
     > Implement a Samba VFS plugin for glusterfs based on gluster's gfapi.
     > This is a "bottom" vfs plugin (not something to be stacked on top of
     > another module), and translates (most) calls into closest actions
     > on gfapi.

    Thank you for your patience here.

     > Signed-off-by: Anand Avati <address@hidden

    <mailto:address@hidden>>

     > ---
     >
     > Hi,
     >
     > I hope the waf changes are fine. I could not test them because
    builds were failing generally on samba.git master HEAD.

    You need to resolve whatever is causing your problems here, as it is not
    a general issue. Our autobuild system ensures that git master and
    v4-0-test always compile and test in at least Ubuntu 10.04, and it is
    incredibly rare that it not work on at least Linux without it being a
    specifically local issue.

    +
    +bld.SAMBA3_MODULE('vfs_glusterfs',
    +                  subsystem='vfs',
    +                  source=VFS_GLUSTERFS_SRC,
    +                  deps='samba-util',
    +                  init_function='',
    +
      internal_module=bld.SAMBA3_IS_STATIC_MODULE('vfs_glusterfs'),
    +
      enabled=bld.SAMBA3_IS_ENABLED_MODULE('vfs_glusterfs'))

    You should ensure your module depends on glusterfs, by changing that to
    adding deps='glusterfs samba-util' (and making that match what the
    conf.check_cfg finds and stores).


I tried that. I added uselib_store='glusterfs' and included 'glusterfs'
in deps= line. However while building I get this error:

address@hidden samba]$ make
WAF_MAKE=1 python ./buildtools/bin/waf build
./buildtools/wafsamba/samba_utils.py:397: DeprecationWarning: the md5
module is deprecated; use hashlib instead
   import md5
Waf: Entering directory `/home/avati/work/samba/bin'
Selected embedded Heimdal build
Checking project rules ...
Unknown dependency 'glusterfs' in 'vfs_glusterfs'
make: *** [all] Error 1


I am not familiar with waf, and trying to figure out how it works. I
don't understand how the check_cfg() in wscript and
source3/wscript_build's bld.SAMBA3_MODULE() actually integrate internally.

     > diff --git a/source3/wscript b/source3/wscript
     > index dba6cdc..0d07692 100644
     > --- a/source3/wscript
     > +++ b/source3/wscript
     > @@ -59,6 +59,11 @@ def set_options(opt):
     >                     help=("Directory under which libcephfs is
    installed"),
     >                     action="" dest='libcephfs_dir',
    default=None)
     >
     > +    opt.add_option('--enable-glusterfs',
     > +                   help=("Enable building vfs_glusterfs module"),
     > +                   action="" dest='enable_glusterfs',
    default=True)
     > +    opt.add_option('--disable-glusterfs', help=SUPPRESS_HELP,
     > +                   action="" dest='enable_glusterfs')

    In general we would prefer not to have options for every possible
    module.  Instead, please just make it automatic based on finding
    glusterfs.


OK, I will just leave things to check_cfg() detection then?

     >  def configure(conf):
     > @@ -1709,6 +1714,13 @@ main() {
     >      if conf.CHECK_HEADERS('cephfs/libcephfs.h', False, False,
    'cephfs') and conf.CHECK_LIB('cephfs'):
     >          conf.DEFINE('HAVE_CEPH', '1')
     >
     > +    conf.env.enable_glusterfs = Options.options.enable_glusterfs
     > +
     > +    if Options.options.enable_glusterfs:
     > +        conf.check_cfg(package='glusterfs-api',
    args='"glusterfs-api >= 4" --cflags --libs',
     > +                       uselib_store='GLUSTERFS', msg='Checking
    for glusterfs-api >= 4',
     > +                       mandatory=False)
     > +
     >      conf.env.build_regedit = False
     >      if not Options.options.with_regedit == False:
     >          conf.PROCESS_SEPARATE_RULE('system_ncurses')
     > @@ -1797,6 +1809,9 @@ main() {
     >      if conf.CONFIG_SET("HAVE_CEPH"):
     >          default_shared_modules.extend(TO_LIST('vfs_ceph'))
     >
     > +    if conf.CONFIG_SET('HAVE_GLUSTERFS'):
     > +        default_shared_modules.extend(TO_LIST('vfs_glusterfs'))
     > +
     >      explicit_shared_modules =
    TO_LIST(Options.options.shared_modules, delimiter=',')
     >      explicit_static_modules =
    TO_LIST(Options.options.static_modules, delimiter=',')

    This much looks good, assuming it is tested and works.   You might need
    to make uselib_store='glusterfs' (not sure).


As mentioned above, I tried this but still get the dependency error. Not
sure what I am missing..

I tried to look up documentation on the web, but I couldn't find anything specific. My understanding so far is:

conf.check_cfg(...) does the 'detection' and stores the result in variables. You can specify a variable name prefix with uselib_store=NAME parameter.

You can then use the test results while building, with a construct like:

bld.new_task_gen(..., uselib=NAME, ...)

However, samba is using bld.SAMBA3_MODULE(...) for building, and that does not seem to be accepting uselib= parameter.

What I am trying to achieve is:

- detect for presence of glusterfs headers/libs in the buildsystem. This is detected with the presence of glusterfs-api.pc

- use the --libs and --cflags from pkg-config on glusterfs-api.pc to build vfs_glusterfs.c

I know how to do this in autotools. I am not familiar with waf, and it doesn't seem to be intuitive enough to be self understood. There seems to be quite a lot of macro hackery around it which makes the techniques you get from a google search "not applicable".

Any help from the waf experts will be most appreciated!

Looks like the issue was that there had to be atleast one call to conf.CHECK_HEADER in context of the package (unlike autotools where this doesn't seem to be necessary). After adding a line to CHECK_HEADERS (in v8 patch) everything else just worked.

Avati