/*{
** Name: DI_slave_write - Request a slave to writes page(s) to a file on disk.
**
** Description:
** This routine was created to make DIwrite more readable once
** error checking had been added. See DIwrite for comments.
**
** Inputs:
** f Pointer to the DI file
** context needed to do I/O.
** diop Pointer to dilru file context.
** buf Pointer to page(s) to write.
** page Value indicating page(s) to write.
** num_of_pages number of pages to write
**
** Outputs:
** err_code Pointer to a variable used
** to return operating system
** errors.
** Returns:
** OK
** other errors.
** Exceptions:
** none
**
** Side Effects:
** none
**
** History:
** 30-nov-1992 (rmuth)
** Created.
** 10-oct-1993 (mikem)
** bug #47624
** Bug 47624 resulted in CSsuspend()'s from the DI system being woken
** up early. Mainline DI would then procede while the slave would
** actually be processing the requested asynchronous action. Various
** bad things could happen after this depending on timing: (mainline
** DI would change the slave control block before slave read it,
** mainline DI would call DIlru_release() and ignore it failing which
** would cause the control block to never be freed eventually leading
** to the server hanging when it ran out of slave control blocks, ...
**
** Fixes were made to scf to hopefully eliminate the unwanted
** CSresume()'s. In addition defensive code has been added to DI
** to catch cases of returning from CSresume while the slave is
** operating, and to check for errors from DIlru_release(). Before
** causing a slave to take action the master will set the slave
** control block status to DI_INPROGRESS, the slave in turn will not
** change this status until it has completed the operation.
**
** The off by one error was caused by the CSsuspend called by
** DI_slave_send() returning early in the case of a DIwrite() of one
** page. The old write loop would increment disl->pre_seek before the
** slave had actually read the control block so the slave would write
** the data from page N to the N+1 location in the file. The
** DI_INPROGRESS flag should stop this, and at least in the one page
** write case we no longer increment disl->pre_seek.
** 23-aug-1993 (bryanp)
** If segment isn't yet mapped, map it!
** 01-oct-1998 (somsa01)
** Return DI_NODISKSPACE when we are out of disk space.
*/
static STATUS
DI_slave_write(
DI_IO *f,
DI_OP *diop,
char *buf,
i4 page,
i4 num_of_pages,
CL_ERR_DESC *err_code)
{
register DI_SLAVE_CB *disl;
ME_SEG_INFO *seginfo;
bool direct_write;
STATUS big_status = OK, small_status = OK;
STATUS intern_status = OK, status;
/* unix variables */
int bytes_to_write;
do
{
disl = diop->di_evcb;
bytes_to_write = (f->io_bytes_per_page * (num_of_pages));
/*
** Determine whether we're writing from shared memory, and set
** up the segment ID and offset correctly.
*/
seginfo = ME_find_seg( buf, (char *)buf + bytes_to_write,
&ME_segpool);
if (seginfo != 0 && (seginfo->flags & ME_SLAVEMAPPED_MASK) == 0)
{
status = DI_lru_slmapmem(seginfo, &intern_status, &small_status);
if (status)
break;
}
if (seginfo != 0 && (seginfo->flags & ME_SLAVEMAPPED_MASK) != 0)
{
direct_write = TRUE;
MEcopy( (PTR)seginfo->key, sizeof(disl->seg_key),
(PTR)disl->seg_key);
disl->seg_offset = (char *)buf - (char *)seginfo->addr;
}
else
{
direct_write = FALSE;
seginfo = ME_find_seg(disl->buf, disl->buf, &ME_segpool);
if (seginfo)
{
MEcopy( (PTR)seginfo->key, sizeof(disl->seg_key),
(PTR)disl->seg_key);
disl->seg_offset= (char *)disl->buf - (char *)seginfo->addr;
}
else
{
small_status = DI_BADWRITE;
break;
}
}
/* Send file properties to slave */
FPROP_COPY(f->io_fprop,disl->io_fprop);
disl->pre_seek =
(OFFSET_TYPE)(f->io_bytes_per_page) * (OFFSET_TYPE)(page);
disl->file_op = DI_SL_WRITE;
/*
** Write the data
*/
do
{
if (direct_write)
disl->length = bytes_to_write;
else
{
disl->length = min(bytes_to_write, Cs_srv_block.cs_size_io_buf);
MEcopy((PTR)buf, disl->length, (PTR)disl->buf);
}
DI_slave_send( disl->dest_slave_no, diop,
&big_status, &small_status, &intern_status);
if (( big_status != OK ) || (small_status != OK ))
break;
if ((small_status = disl->status) != OK )
{
STRUCT_ASSIGN_MACRO(disl->errcode, *err_code);
}
if ((small_status != OK) || (disl->length == 0))
{
switch( err_code->errnum )
{
case EFBIG:
small_status = DI_BADEXTEND;
break;
case ENOSPC:
small_status = DI_NODISKSPACE;
break;
#ifdef EDQUOT
case EDQUOT:
small_status = DI_EXCEED_LIMIT;
break;
#endif
default:
small_status = DI_BADWRITE;
break;
}
break;
}
bytes_to_write -= disl->length;
buf += disl->length;
if (bytes_to_write > 0)
disl->pre_seek += (OFFSET_TYPE)disl->length;
} while ( bytes_to_write > 0);
} while (FALSE);
if (big_status != OK )
small_status = big_status;
if (small_status != OK )
DIlru_set_di_error( &small_status, err_code, intern_status,
DI_GENERAL_ERR);
return( small_status );
}
/*{
** Name: DI_slave_read - Request a slave to read page(s) from a file on disk.
**
** Description:
** This routine was created to make DIread more readable once
** error checking had been added. See DIread for comments.
**
** Inputs:
** f Pointer to the DI file
** context needed to do I/O.
** diop Pointer to dilru file context.
** buf Pointer to page(s) to read.
** page Value indicating page(s) to read.
** num_of_pages number of pages to read.
**
** Outputs:
** err_code Pointer to a variable used
** to return operating system
** errors.
** Returns:
** OK
** other errors.
** Exceptions:
** none
**
** Side Effects:
** none
**
** History:
** 30-nov-1992 (rmuth)
** Created.
** 10-mar-1993 (mikem)
** Changed the type of the first parameter to DI_send_ev_to_slave() and
** the 2nd parameter to DI_slave_send(), so that DI_send_ev_to_slave()
** could access the slave control block's status.
** This routine will now initialize the status to DI_INPROGRESS, before
** making the request and the slave will change the status once the
** operation is complete.
** 23-aug-1993 (bryanp)
** If memory segment isn't yet mapped, map it.
*/
static STATUS
DI_slave_read(
DI_IO *f,
DI_OP *diop,
char *buf,
i4 page,
i4 num_of_pages,
i4 *n,
CL_ERR_DESC *err_code)
{
register DI_SLAVE_CB *disl;
ME_SEG_INFO *seginfo;
bool direct_read;
STATUS small_status = OK, big_status = OK,
intern_status = OK, status;
/* unix variables */
int bytes_to_read;
int bytes_read = 0;
do
{
disl = diop->di_evcb;
disl->pre_seek =
(OFFSET_TYPE)(f->io_bytes_per_page) * (OFFSET_TYPE)(page);
bytes_to_read = f->io_bytes_per_page * num_of_pages;
/*
** determine whether we're reading into shared memory, and set
** up the segment ID and offset correctly
*/
seginfo = ME_find_seg( buf, (char *)buf + bytes_to_read,
&ME_segpool);
if (seginfo != 0 && (seginfo->flags & ME_SLAVEMAPPED_MASK) == 0)
{
status = DI_lru_slmapmem(seginfo, &intern_status, &small_status);
if (status)
break;
}
if (seginfo != 0 && (seginfo->flags & ME_SLAVEMAPPED_MASK) != 0)
{
MEcopy( (PTR)seginfo->key, sizeof(disl->seg_key),
(PTR)disl->seg_key);
disl->seg_offset = (char *)buf - (char *)seginfo->addr;
direct_read = TRUE;
}
else
{
direct_read = FALSE;
seginfo = ME_find_seg(disl->buf, disl->buf, &ME_segpool);
if (seginfo)
{
MEcopy( (PTR)seginfo->key, sizeof(disl->seg_key),
(PTR)disl->seg_key);
disl->seg_offset= (char *)disl->buf - (char *)seginfo->addr;
}
else
{
small_status = DI_BADREAD;
break;
}
}
/*
** seek to place to read
*/
do
{
disl->file_op = DI_SL_READ;
/* Send file properties to slave */
FPROP_COPY(f->io_fprop,disl->io_fprop);
if (direct_read)
disl->length = bytes_to_read;
else
disl->length = min(bytes_to_read, Cs_srv_block.cs_size_io_buf);
DI_slave_send( disl->dest_slave_no, diop,
&big_status, &small_status, &intern_status);
if (( big_status != OK ) || ( small_status != OK ))
break;
if ((small_status = disl->status) != OK )
{
STRUCT_ASSIGN_MACRO(disl->errcode, *err_code);
small_status = DI_BADREAD;
break;
}
else
{
if ( disl->length == 0 )
{
small_status = DI_ENDFILE;
#ifdef xDEV_TST
TRdisplay("num_pages %d\n, read_op = %x",
num_of_pages, 0x70000000);
DIlru_dump();
#endif /* xDev_TST */
break;
}
}
/*
** Read data ok
*/
if (! direct_read)
{
MEcopy((PTR)disl->buf, disl->length, (PTR)buf);
buf += disl->length;
}
bytes_to_read -= disl->length;
disl->pre_seek += (OFFSET_TYPE)disl->length;
bytes_read += disl->length;
} while ( bytes_to_read > 0);
} while (FALSE);
if ( bytes_read > 0 )
*n = bytes_read / f->io_bytes_per_page;
if ( big_status != OK )
small_status = big_status;
if (small_status != OK )
DIlru_set_di_error( &small_status, err_code, intern_status,
DI_GENERAL_ERR);
return(small_status);
}
