diff options
Diffstat (limited to 'sys/fmio/fmsync.x')
| -rw-r--r-- | sys/fmio/fmsync.x | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/sys/fmio/fmsync.x b/sys/fmio/fmsync.x new file mode 100644 index 00000000..7c7d8112 --- /dev/null +++ b/sys/fmio/fmsync.x @@ -0,0 +1,169 @@ +# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc. + +include <syserr.h> +include <mach.h> +include <knet.h> +include "fmio.h" + +define SZB_SHORT (SZB_CHAR*SZ_SHORT) + +# FM_SYNC -- Update any buffered portions of the datafile on disk which have +# been modified since the last update. + +procedure fm_sync (fm) + +pointer fm #I FMIO descriptor + +pointer sp, ip, op, dhbuf, pgbuf, pti, dh, ft, pt +int maxpages, nbytes, npti, p1, p2, d1, d2, dp, i +int szbpage, chan, buflen, status, npte_perpage +int fmio_extend() +long clktime() + +begin + if (FM_MODE(fm) == READ_ONLY) + return + + call smark (sp) + chan = FM_CHAN(fm) + szbpage = FM_SZBPAGE(fm) + npte_perpage = szbpage / SZB_SHORT + + call intr_disable() + + # Get more page table space (pages). During a normal file extend + # occurring while writing to a file, PTEs for *data* pages are added + # to the incore global page table and to the PT for the lfile. + # The additional pages needed to store the PT and PTI as they grow + # are however not allocated during i/o. We wait and do this at sync + # time to provide maximal separation of the data pages and PT pages, + # rendering both as contiguous as possible. + + # Check for page table index overflow (datafile too large). + npti = (FM_PTNPTE(fm) + npte_perpage-1) / npte_perpage + if (npti > FM_PTILEN(fm)) { + call fmio_posterr (fm, SYS_FMPTIOVFL, FM_DFNAME(fm)) + + # Truncate the page table to try to recover the datafile with + # some loss of data. + + npti = FM_PTILEN(fm) + FM_PTNPTE(fm) = npti * npte_perpage - (npti - FM_PTINPTI(fm)) + } + + # Allocate the page table pages. + for (p1=FM_PTINPTI(fm)+1; p1 <= npti; p1=p1+1) { + dp = fmio_extend (fm, PT_LFILE, 1) + if (dp != ERR) { + Memi[FM_PTINDEX(fm)+p1-1] = dp + FM_PTINPTI(fm) = p1 + FM_DHMODIFIED(fm) = YES + } else + call fmio_posterr (fm, SYS_FMPTIOVFL, FM_DFNAME(fm)) + } + + # Update the datafile header area. + if (FM_DHMODIFIED(fm) != NO) { + # Allocate a buffer to hold the encoded datafile header area. + buflen = (FM_DATASTART(fm) - 1) / (SZ_STRUCT * SZB_CHAR) + call salloc (dhbuf, buflen, TY_STRUCT) + + # Encode and output the datafile header. + call salloc (dh, LEN_DHSTRUCT, TY_STRUCT) + + DH_MAGIC(dh) = FMIO_MAGIC + DH_DFVERSION(dh) = FM_DFVERSION(fm) + DH_SZBPAGE(dh) = szbpage + DH_NLFILES(dh) = FM_NLFILES(fm) + DH_FTOFF(dh) = FM_FTOFF(fm) + DH_FTLASTNF(dh) = FM_FTLASTNF(fm) + DH_PTIOFF(dh) = FM_PTIOFF(fm) + DH_PTILEN(dh) = FM_PTILEN(fm) + DH_PTINPTI(dh) = FM_PTINPTI(fm) + DH_PTLEN(dh) = FM_PTLEN(fm) + DH_PTNPTE(dh) = FM_PTNPTE(fm) + DH_DATASTART(dh) = FM_DATASTART(fm) + + call miipak32 (Memi[dh], Memi[dhbuf], LEN_DHSTRUCT, TY_STRUCT) + + # Output the file table. + ft = FM_FTABLE(fm) + op = dhbuf + FM_FTOFF(fm) - 1 + do i = 0, FM_NLFILES(fm) { + ip = ft + i * LEN_FTE + FT_FSIZE(op) = LF_FSIZE(ip) + FT_FLAGS(op) = and (LFF_SAVE, LF_FLAGS(ip)) + op = op + LEN_FTEX + } + + op = dhbuf + FM_FTOFF(fm) - 1 + call miipak32 (Memi[op], Memi[op], + (FM_NLFILES(fm) + 1) * LEN_FTEX, TY_INT) + + # Output the page table index. + call miipak32 (Memi[FM_PTINDEX(fm)], Memi[dhbuf+FM_PTIOFF(fm)-1], + FM_PTILEN(fm), TY_INT) + + # Update the whole thing on disk. + call zawrbf (chan, Memi[dhbuf], FM_DATASTART(fm)-1, 1) + call zawtbf (chan, status) + if (status == ERR) + call fmio_posterr (fm, SYS_FMWRERR, FM_DFNAME(fm)) + + FM_DHMODIFIED(fm) = NO + } + + # Don't cache these pointers before calling fmio_extend! + pt = FM_PTABLE(fm) + pti = FM_PTINDEX(fm) + + # Update the page table itself, stored in the data pages. + if (FM_PTNPTE(fm) > FM_PTLUPTE(fm)) { + + # Determine the max transfer size. + maxpages = FM_MAXBUFSIZE(fm) / szbpage + if (maxpages <= 0) + maxpages = DEF_BIGBUFNP + + # Get an output temporary buffer if we have to swap on output. + if (BYTE_SWAP2 == YES) + call salloc (pgbuf, maxpages * szbpage / SZB_SHORT, TY_SHORT) + + # Determine the PT page containing the LUPTE+1. + p1 = FM_PTLUPTE(fm) / npte_perpage + 1 + + # Update that and all following PT pages. + npti = FM_PTINPTI(fm) + for (; p1 <= npti; p1=p2) { + # Get a contiguous range of page table pages. + d1 = Memi[pti+p1-1] + for (p2=p1+1; p2 <= npti; p2=p2+1) { + d2 = Memi[pti+p2-1] + if (d2-d1 != p2-p1 || p2-p1 >= maxpages) + break + } + + # Swap the data and set IP for the output transfer. + ip = pt + (p1 - 1) * npte_perpage + nbytes = (min(npti+1,p2) - p1) * szbpage + if (BYTE_SWAP2 == YES) { + call bswap2 (Mems[ip], 1, Mems[pgbuf], 1, nbytes) + ip = pgbuf + } + + # Update the pages. + call zawrbf (chan, Mems[ip], nbytes, + (d1-1) * szbpage + FM_DATASTART(fm)) + call zawtbf (chan, status) + if (status < nbytes) + call fmio_posterr (fm, SYS_FMWRERR, FM_DFNAME(fm)) + } + + FM_PTLUPTE(fm) = FM_PTNPTE(fm) + } + + FM_LSYNCTIME(fm) = clktime(0) + call intr_enable() + + call sfree (sp) +end |