Re: FIRST_CHILD(frame->this)->fops->create

"Ian Latter" <ian.latter@xxxxxxxxxxxxxxxx> · Thu, 06 Aug 2009 15:07:50 +1000

Excellent - thanks Avati.

This also, then, confirms that my fd_create() version was
failing because of the incorrectly populated loc structure.

It also didn't occur to me that the server xlator would have
the type of sample code I could use for this ... I'm working
my way through server_create() now ... and server_loc_fill()
from server-helpers.c ...

It looks like you've opened some good avenues here; if I
get stuck I'll post back.

Thanks for your help - I look forward to contributing to the
project.

----- Original Message -----
>From: "Anand Avati" <avati@xxxxxxxxxxx>
>To: "Ian Latter" <ian.latter@xxxxxxxxxxxxxxxx>
>Subject:  Re: [Gluster-devel]
FIRST_CHILD(frame->this)->fops->create
>Date: Wed, 05 Aug 2009 20:29:27 -0700
>
> If this is the actual code below you have in your fop,
please look for
> the comments inline -
> 
> > Example code for the "hang" case, from my prototype (inside
> > a function called from inside the xlator->write handler);
> >
> > ï¿½ ï¿½ ï¿½ ï¿½loc_t data_loc;
> > ï¿½ ï¿½ ï¿½ ï¿½char path[255];
> > ï¿½ ï¿½ ï¿½ ï¿½char name[255];
> > ï¿½ ï¿½ ï¿½ ï¿½char * data_path;
> > ï¿½ ï¿½ ï¿½ ï¿½char * data_name;
> > ï¿½ ï¿½ ï¿½ ï¿½int32_t flags;
> > ï¿½ ï¿½ ï¿½ ï¿½mode_t mode;
> > ï¿½ ï¿½ ï¿½ ï¿½fd_t * fd;
> >
> > ï¿½ ï¿½ ï¿½ ï¿½memset(path, 0, sizeof(path));
> > ï¿½ ï¿½ ï¿½ ï¿½if(snprintf(path, sizeof(path) - 1, "/data.db") <= 0)
> > ï¿½ ï¿½ ï¿½ ï¿½ ï¿½return -1;
> >
> > ï¿½ ï¿½ ï¿½ ï¿½memset(name, 0, sizeof(name));
> > ï¿½ ï¿½ ï¿½ ï¿½if(snprintf(name, sizeof(name) - 1, "data.db") <= 0)
> > ï¿½ ï¿½ ï¿½ ï¿½ ï¿½return -1;
> >
> > ï¿½ ï¿½ ï¿½ ï¿½data_path = CALLOC(1, strlen(path) + 1);
> > ï¿½ ï¿½ ï¿½ ï¿½ERR_ABORT(data_path);
> > ï¿½ ï¿½ ï¿½ ï¿½memset(data_path, 0, sizeof(data_path));
> > ï¿½ ï¿½ ï¿½ ï¿½memcpy(data_path, path, strlen(path));
> >
> > ï¿½ ï¿½ ï¿½ ï¿½data_name = CALLOC(1, strlen(name) + 1);
> > ï¿½ ï¿½ ï¿½ ï¿½ERR_ABORT(data_name);
> > ï¿½ ï¿½ ï¿½ ï¿½memset(data_name, 0, sizeof(data_name));
> > ï¿½ ï¿½ ï¿½ ï¿½memcpy(data_name, name, strlen(name));
> >
> > ï¿½ ï¿½ ï¿½ ï¿½memset(&data_loc, 0, sizeof(data_loc));
> > ï¿½ ï¿½ ï¿½ ï¿½data_loc.inode = NULL; ï¿½// redundant
> 
> you need to have the loc->inode and loc->parent members
filled in
> properly. See fuse-bridge.c and server-protocol.c on how
to generate
> create()able inodes and fds. To reach the parent inode of the
> directory where the file needs to be created, refer the
> fuse_loc_fill() or server_loc_fill() functions.
> 
> > ï¿½ ï¿½ ï¿½ ï¿½data_loc.path = data_path;
> > ï¿½ ï¿½ ï¿½ ï¿½data_loc.name = data_name;
> >
> > ï¿½ ï¿½ ï¿½ ï¿½flags = O_CREAT | O_RDWR | O_EXCL;
> >
> > ï¿½ ï¿½ ï¿½ ï¿½mode = (mode_t)0700;
> >
> > ï¿½ ï¿½ ï¿½ ï¿½memset(fd, 0, sizeof(fd_t));
> >
> > ï¿½ ï¿½ ï¿½ ï¿½STACK_WIND(frame,
> > ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½xlator_func_writev_create_cbk,
> > ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½FIRST_CHILD(frame->this),
> > ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½FIRST_CHILD(frame->this)->fops->create,
> > ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½ ï¿½&data_loc, flags, mode, &fd);
> 
> the fd pointer should be pre-allocated with fd_create(). Refer
> fuse_create() and fuse_create_cbk() to figure out the
right things to
> do. If you can describe your requirements in more detail,
we can
> suggest a few tips and directions on how to proceed.
> 
> > ï¿½ ï¿½ ï¿½ ï¿½gf_log(this->name, GF_LOG_WARNING, "Hung above me");
> 
> Avati
> 

--
Ian Latter
Late night coder ..
http://midnightcode.org/