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0911b330a0
avoids a race condition where multiple RAID-5 subdisks are being revived at the same time. The locks should also prevent conflicts with user requests on concatenated and striped plexes, but this needs more work. Tidy up some comments.
282 lines
10 KiB
C
282 lines
10 KiB
C
/*-
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* Copyright (c) 1997, 1998, 1999
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* Nan Yang Computer Services Limited. All rights reserved.
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*
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* Parts copyright (c) 1997, 1998 Cybernet Corporation, NetMAX project.
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*
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* Written by Greg Lehey
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*
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* This software is distributed under the so-called ``Berkeley
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* License'':
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Nan Yang Computer
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* Services Limited.
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* 4. Neither the name of the Company nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* This software is provided ``as is'', and any express or implied
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* warranties, including, but not limited to, the implied warranties of
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* merchantability and fitness for a particular purpose are disclaimed.
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* In no event shall the company or contributors be liable for any
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* direct, indirect, incidental, special, exemplary, or consequential
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* damages (including, but not limited to, procurement of substitute
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* goods or services; loss of use, data, or profits; or business
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* interruption) however caused and on any theory of liability, whether
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* in contract, strict liability, or tort (including negligence or
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* otherwise) arising in any way out of the use of this software, even if
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* advised of the possibility of such damage.
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*
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* $Id: vinumrevive.c,v 1.8 1999/06/28 01:57:50 grog Exp grog $
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*/
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#include <dev/vinum/vinumhdr.h>
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#include <dev/vinum/request.h>
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/*
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* Revive a block of a subdisk. Return an error
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* indication. EAGAIN means successful copy, but
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* that more blocks remain to be copied. EINVAL
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* means that the subdisk isn't associated with a
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* plex (which means a programming error if we get
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* here at all; FIXME).
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*/
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int
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revive_block(int sdno)
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{
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struct sd *sd;
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struct plex *plex;
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struct volume *vol;
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struct buf *bp;
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int error = EAGAIN;
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int size; /* size of revive block, bytes */
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int s; /* priority level */
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daddr_t plexblkno; /* lblkno in plex */
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int psd; /* parity subdisk number */
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int stripe; /* stripe number */
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int isparity = 0; /* set if this is the parity stripe */
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struct rangelock *lock; /* for locking */
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plexblkno = 0; /* to keep the compiler happy */
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sd = &SD[sdno];
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lock = NULL;
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if (sd->plexno < 0) /* no plex? */
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return EINVAL;
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plex = &PLEX[sd->plexno]; /* point to plex */
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if (plex->volno >= 0)
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vol = &VOL[plex->volno];
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else
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vol = NULL;
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if (sd->revive_blocksize == 0) {
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if (plex->stripesize != 0) /* we're striped, don't revive more than */
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sd->revive_blocksize = min(DEFAULT_REVIVE_BLOCKSIZE, /* one block at a time */
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plex->stripesize << DEV_BSHIFT);
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else
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sd->revive_blocksize = DEFAULT_REVIVE_BLOCKSIZE;
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}
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size = min(sd->revive_blocksize >> DEV_BSHIFT, sd->sectors - sd->revived) << DEV_BSHIFT;
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s = splbio();
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bp = geteblk(size); /* Get a buffer */
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if (bp == NULL) {
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splx(s);
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return ENOMEM;
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}
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if (bp->b_qindex != 0) /* on a queue, */
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bremfree(bp); /* remove it XXX how can this happen? */
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splx(s);
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/*
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* Amount to transfer: block size, unless it
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* would overlap the end
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*/
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bp->b_bufsize = size;
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bp->b_bcount = bp->b_bufsize;
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bp->b_resid = 0;
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/* Now decide where to read from */
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switch (plex->organization) {
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daddr_t stripeoffset; /* offset in stripe */
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case plex_concat:
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plexblkno = sd->revived + sd->plexoffset; /* corresponding address in plex */
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break;
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case plex_striped:
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stripeoffset = sd->revived % plex->stripesize; /* offset from beginning of stripe */
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plexblkno = sd->plexoffset /* base */
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+ (sd->revived - stripeoffset) * plex->subdisks /* offset to beginning of stripe */
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+ sd->revived % plex->stripesize; /* offset from beginning of stripe */
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lock = lockrange(plexblkno << DEV_BSHIFT, bp, plex); /* lock it */
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break;
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case plex_raid5:
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stripeoffset = sd->revived % plex->stripesize; /* offset from beginning of stripe */
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plexblkno = sd->plexoffset /* base */
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+ (sd->revived - stripeoffset) * (plex->subdisks - 1) /* offset to beginning of stripe */
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+sd->revived % plex->stripesize; /* offset from beginning of stripe */
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stripe = (sd->revived / plex->stripesize); /* stripe number */
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psd = plex->subdisks - 1 - stripe % plex->subdisks; /* parity subdisk for this stripe */
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isparity = plex->sdnos[psd] == sdno; /* note if it's the parity subdisk */
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/*
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* Now adjust for the strangenesses
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* in RAID-5 striping.
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*/
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if (sd->plexsdno > psd) /* beyond the parity stripe, */
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plexblkno -= plex->stripesize; /* one stripe less */
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lock = lockrange(plexblkno << DEV_BSHIFT, bp, plex); /* lock it */
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break;
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case plex_disorg: /* to keep the compiler happy */
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}
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if (isparity) { /* we're reviving a parity block, */
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int mysdno;
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int *tbuf; /* temporary buffer to read the stuff in to */
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caddr_t parity_buf; /* the address supplied by geteblk */
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int isize;
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int i;
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tbuf = (int *) Malloc(size);
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isize = size / (sizeof(int)); /* number of ints in the buffer */
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/*
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* We have calculated plexblkno assuming it
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* was a data block. Go back to the beginning
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* of the band.
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*/
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plexblkno -= plex->stripesize * sd->plexsdno;
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/*
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* Read each subdisk in turn, except for this
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* one, and xor them together.
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*/
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parity_buf = bp->b_data; /* save the buffer getblk gave us */
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bzero(parity_buf, size); /* start with nothing */
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bp->b_data = (caddr_t) tbuf; /* read into here */
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for (mysdno = 0; mysdno < plex->subdisks; mysdno++) { /* for each subdisk */
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if (mysdno != sdno) { /* not our subdisk */
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if (vol != NULL) /* it's part of a volume, */
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/*
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* First, read the data from the volume.
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* We don't care which plex, that's the
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* driver's job.
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*/
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bp->b_dev = VINUMBDEV(plex->volno, 0, 0, VINUM_VOLUME_TYPE); /* create the device number */
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else /* it's an unattached plex */
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bp->b_dev = VINUMRBDEV(sd->plexno, VINUM_RAWPLEX_TYPE); /* create the device number */
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bp->b_blkno = plexblkno; /* read from here */
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bp->b_flags = B_READ; /* either way, read it */
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BUF_LOCKINIT(bp); /* get a lock for the buffer */
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BUF_LOCK(bp, LK_EXCLUSIVE); /* and lock it */
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vinumstart(bp, 1);
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biowait(bp);
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if (bp->b_flags & B_ERROR) /* can't read, */
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/*
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* If we have a read error, there's
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* nothing we can do. By this time, the
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* daemon has already run out of magic.
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*/
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break;
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/*
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* To save time, we do the XOR wordwise.
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* This requires sectors to be a multiple
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* of the length of an int, which is
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* currently always the case.
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*/
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for (i = 0; i < isize; i++)
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((int *) parity_buf)[i] ^= tbuf[i]; /* xor in the buffer */
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plexblkno += plex->stripesize; /* move on to the next subdisk */
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}
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}
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bp->b_data = parity_buf; /* put the buf header back the way it was */
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Free(tbuf);
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} else {
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bp->b_blkno = plexblkno; /* start here */
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if (vol != NULL) /* it's part of a volume, */
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/*
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* First, read the data from the volume. We
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* don't care which plex, that's bre's job.
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*/
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bp->b_dev = VINUMBDEV(plex->volno, 0, 0, VINUM_VOLUME_TYPE); /* create the device number */
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else /* it's an unattached plex */
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bp->b_dev = VINUMRBDEV(sd->plexno, VINUM_RAWPLEX_TYPE); /* create the device number */
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bp->b_flags = B_READ; /* either way, read it */
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vinumstart(bp, 1);
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biowait(bp);
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}
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if (bp->b_flags & B_ERROR)
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error = bp->b_error;
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else
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/* Now write to the subdisk */
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{
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s = splbio();
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if (bp->b_qindex != 0) /* on a queue, */
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bremfree(bp); /* remove it */
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splx(s);
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bp->b_dev = VINUMRBDEV(sdno, VINUM_RAWSD_TYPE); /* create the device number */
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bp->b_flags = B_ORDERED; /* and make this an ordered write */
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BUF_LOCKINIT(bp); /* get a lock for the buffer */
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BUF_LOCK(bp, LK_EXCLUSIVE); /* and lock it */
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bp->b_resid = 0x0;
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bp->b_blkno = sd->revived; /* write it to here */
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sdio(bp); /* perform the I/O */
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biowait(bp);
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if (bp->b_flags & B_ERROR)
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error = bp->b_error;
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else {
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sd->revived += bp->b_bcount >> DEV_BSHIFT; /* moved this much further down */
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if (sd->revived >= sd->sectors) { /* finished */
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sd->revived = 0;
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set_sd_state(sdno, sd_up, setstate_force); /* bring the sd up */
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log(LOG_INFO, "vinum: %s is %s\n", sd->name, sd_state(sd->state));
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save_config(); /* and save the updated configuration */
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error = 0; /* we're done */
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}
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}
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if (lock) /* we took a lock, */
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unlockrange(sd->plexno, lock); /* give it back */
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while (sd->waitlist) { /* we have waiting requests */
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#if VINUMDEBUG
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struct request *rq = sd->waitlist;
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if (debug & DEBUG_REVIVECONFLICT)
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log(LOG_DEBUG,
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"Relaunch revive conflict sd %d: %x\n%s dev %d.%d, offset 0x%x, length %ld\n",
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rq->sdno,
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(u_int) rq,
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rq->bp->b_flags & B_READ ? "Read" : "Write",
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major(rq->bp->b_dev),
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minor(rq->bp->b_dev),
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rq->bp->b_blkno,
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rq->bp->b_bcount);
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#endif
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launch_requests(sd->waitlist, 1); /* do them now */
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sd->waitlist = sd->waitlist->next; /* and move on to the next */
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}
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}
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if (bp->b_qindex == 0) /* not on a queue, */
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brelse(bp); /* is this kosher? */
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return error;
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}
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/* Local Variables: */
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/* fill-column: 50 */
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/* End: */
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