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authordillon <dillon@FreeBSD.org>1999-09-23 09:25:05 +0000
committerdillon <dillon@FreeBSD.org>1999-09-23 09:25:05 +0000
commit52ab2170f360b6ba294006092ce416c13cf9276b (patch)
treef0aad5d09079eb1d4abadb42b85e8b22fc3b22f1 /sys/geom
parentc3199b7ad062a8f76e410357e44a8e69ebae7159 (diff)
downloadFreeBSD-src-52ab2170f360b6ba294006092ce416c13cf9276b.zip
FreeBSD-src-52ab2170f360b6ba294006092ce416c13cf9276b.tar.gz
Cleanup CCD quite a bit, including adding clarifying comments.
Enhance MIRROR code. Add a few more sanity checks and implement a zone-based disk selector to make use of both disks when reading. Also implement a read fail-over. If a read error occurs on one disk, the I/O is retried on the other. NOTE: CCD's mirroring support cannot deal with write errors properly in regards to recovery, meaning that 'old' data under a write error may be read non-deterministically if you reboot after a write error, and CCD certainly cannot deal with a disk changeout. And it still can't. Use vinum if you are really serious about mirroring. CCD basically just implements a poor-man's mirror.
Diffstat (limited to 'sys/geom')
-rw-r--r--sys/geom/geom_ccd.c504
1 files changed, 357 insertions, 147 deletions
diff --git a/sys/geom/geom_ccd.c b/sys/geom/geom_ccd.c
index 19d765c..06592b5 100644
--- a/sys/geom/geom_ccd.c
+++ b/sys/geom/geom_ccd.c
@@ -146,6 +146,7 @@ SYSCTL_INT(_debug, OID_AUTO, ccddebug, CTLFLAG_RW, &ccddebug, 0, "");
struct ccdbuf {
struct buf cb_buf; /* new I/O buf */
struct buf *cb_obp; /* ptr. to original I/O buf */
+ struct ccdbuf *cb_freenext; /* free list link */
int cb_unit; /* target unit */
int cb_comp; /* target component */
int cb_pflags; /* mirror/parity status flag */
@@ -155,11 +156,6 @@ struct ccdbuf {
/* bits in cb_pflags */
#define CCDPF_MIRROR_DONE 1 /* if set, mirror counterpart is done */
-#define getccdbuf() \
- ((struct ccdbuf *)malloc(sizeof(struct ccdbuf), M_DEVBUF, M_WAITOK))
-#define putccdbuf(cbp) \
- free((caddr_t)(cbp), M_DEVBUF)
-
#define CCDLABELDEV(dev) \
(makedev(major((dev)), dkmakeminor(ccdunit((dev)), 0, RAW_PART)))
@@ -170,6 +166,8 @@ static d_ioctl_t ccdioctl;
static d_dump_t ccddump;
static d_psize_t ccdsize;
+#define NCCDFREEHIWAT 16
+
#define CDEV_MAJOR 74
#define BDEV_MAJOR 21
@@ -221,9 +219,71 @@ static void printiinfo __P((struct ccdiinfo *));
/* Non-private for the benefit of libkvm. */
struct ccd_softc *ccd_softc;
struct ccddevice *ccddevs;
+struct ccdbuf *ccdfreebufs;
+static int numccdfreebufs;
static int numccd = 0;
/*
+ * getccdbuf() - Allocate and zero a ccd buffer.
+ *
+ * This routine is called at splbio().
+ */
+
+static __inline
+struct ccdbuf *
+getccdbuf(struct ccdbuf *cpy)
+{
+ struct ccdbuf *cbp;
+
+ /*
+ * Allocate from freelist or malloc as necessary
+ */
+ if ((cbp = ccdfreebufs) != NULL) {
+ ccdfreebufs = cbp->cb_freenext;
+ --numccdfreebufs;
+ } else {
+ cbp = malloc(sizeof(struct ccdbuf), M_DEVBUF, M_WAITOK);
+ }
+
+ /*
+ * Used by mirroring code
+ */
+ if (cpy)
+ bcopy(cpy, cbp, sizeof(struct ccdbuf));
+ else
+ bzero(cbp, sizeof(struct ccdbuf));
+
+ /*
+ * independant struct buf initialization
+ */
+ LIST_INIT(&cbp->cb_buf.b_dep);
+ BUF_LOCKINIT(&cbp->cb_buf);
+ BUF_LOCK(&cbp->cb_buf, LK_EXCLUSIVE);
+
+ return(cbp);
+}
+
+/*
+ * putccdbuf() - Allocate and zero a ccd buffer.
+ *
+ * This routine is called at splbio().
+ */
+
+static __inline
+void
+putccdbuf(struct ccdbuf *cbp)
+{
+ if (numccdfreebufs < NCCDFREEHIWAT) {
+ cbp->cb_freenext = ccdfreebufs;
+ ccdfreebufs = cbp;
+ ++numccdfreebufs;
+ } else {
+ free((caddr_t)cbp, M_DEVBUF);
+ }
+}
+
+
+/*
* Number of blocks to untouched in front of a component partition.
* This is to avoid violating its disklabel area when it starts at the
* beginning of the slice.
@@ -301,17 +361,17 @@ ccdinit(ccd, cpaths, p)
char **cpaths;
struct proc *p;
{
- register struct ccd_softc *cs = &ccd_softc[ccd->ccd_unit];
- register struct ccdcinfo *ci = NULL; /* XXX */
- register size_t size;
- register int ix;
+ struct ccd_softc *cs = &ccd_softc[ccd->ccd_unit];
+ struct ccdcinfo *ci = NULL; /* XXX */
+ size_t size;
+ int ix;
struct vnode *vp;
size_t minsize;
int maxsecsize;
struct partinfo dpart;
struct ccdgeom *ccg = &cs->sc_geom;
char tmppath[MAXPATHLEN];
- int error;
+ int error = 0;
#ifdef DEBUG
if (ccddebug & (CCDB_FOLLOW|CCDB_INIT))
@@ -348,12 +408,7 @@ ccdinit(ccd, cpaths, p)
printf("ccd%d: can't copy path, error = %d\n",
ccd->ccd_unit, error);
#endif
- while (ci > cs->sc_cinfo) {
- ci--;
- free(ci->ci_path, M_DEVBUF);
- }
- free(cs->sc_cinfo, M_DEVBUF);
- return (error);
+ goto fail;
}
ci->ci_path = malloc(ci->ci_pathlen, M_DEVBUF, M_WAITOK);
bcopy(tmppath, ci->ci_path, ci->ci_pathlen);
@@ -370,12 +425,7 @@ ccdinit(ccd, cpaths, p)
printf("ccd%d: %s: ioctl failed, error = %d\n",
ccd->ccd_unit, ci->ci_path, error);
#endif
- while (ci >= cs->sc_cinfo) {
- free(ci->ci_path, M_DEVBUF);
- ci--;
- }
- free(cs->sc_cinfo, M_DEVBUF);
- return (error);
+ goto fail;
}
if (dpart.part->p_fstype == FS_BSDFFS) {
maxsecsize =
@@ -388,12 +438,8 @@ ccdinit(ccd, cpaths, p)
printf("ccd%d: %s: incorrect partition type\n",
ccd->ccd_unit, ci->ci_path);
#endif
- while (ci >= cs->sc_cinfo) {
- free(ci->ci_path, M_DEVBUF);
- ci--;
- }
- free(cs->sc_cinfo, M_DEVBUF);
- return (EFTYPE);
+ error = EFTYPE;
+ goto fail;
}
/*
@@ -410,12 +456,8 @@ ccdinit(ccd, cpaths, p)
printf("ccd%d: %s: size == 0\n",
ccd->ccd_unit, ci->ci_path);
#endif
- while (ci >= cs->sc_cinfo) {
- free(ci->ci_path, M_DEVBUF);
- ci--;
- }
- free(cs->sc_cinfo, M_DEVBUF);
- return (ENODEV);
+ error = ENODEV;
+ goto fail;
}
if (minsize == 0 || size < minsize)
@@ -435,42 +477,52 @@ ccdinit(ccd, cpaths, p)
printf("ccd%d: interleave must be at least %d\n",
ccd->ccd_unit, (maxsecsize / DEV_BSIZE));
#endif
- while (ci >= cs->sc_cinfo) {
- free(ci->ci_path, M_DEVBUF);
- ci--;
- }
- free(cs->sc_cinfo, M_DEVBUF);
- return (EINVAL);
+ error = EINVAL;
+ goto fail;
}
/*
* If uniform interleave is desired set all sizes to that of
- * the smallest component.
+ * the smallest component. This will guarentee that a single
+ * interleave table is generated.
+ *
+ * Lost space must be taken into account when calculating the
+ * overall size. Half the space is lost when CCDF_MIRROR is
+ * specified. One disk is lost when CCDF_PARITY is specified.
*/
if (ccd->ccd_flags & CCDF_UNIFORM) {
for (ci = cs->sc_cinfo;
- ci < &cs->sc_cinfo[cs->sc_nccdisks]; ci++)
+ ci < &cs->sc_cinfo[cs->sc_nccdisks]; ci++) {
ci->ci_size = minsize;
+ }
if (ccd->ccd_flags & CCDF_MIRROR) {
/*
* Check to see if an even number of components
- * have been specified.
+ * have been specified. The interleave must also
+ * be non-zero in order for us to be able to
+ * guarentee the topology.
*/
if (cs->sc_nccdisks % 2) {
printf("ccd%d: mirroring requires an even number of disks\n", ccd->ccd_unit );
- while (ci > cs->sc_cinfo) {
- ci--;
- free(ci->ci_path, M_DEVBUF);
- }
- free(cs->sc_cinfo, M_DEVBUF);
- return (EINVAL);
+ error = EINVAL;
+ goto fail;
+ }
+ if (cs->sc_ileave == 0) {
+ printf("ccd%d: an interleave must be specified when mirroring\n", ccd->ccd_unit);
+ error = EINVAL;
+ goto fail;
}
cs->sc_size = (cs->sc_nccdisks/2) * minsize;
- }
- else if (ccd->ccd_flags & CCDF_PARITY)
+ } else if (ccd->ccd_flags & CCDF_PARITY) {
cs->sc_size = (cs->sc_nccdisks-1) * minsize;
- else
+ } else {
+ if (cs->sc_ileave == 0) {
+ printf("ccd%d: an interleave must be specified when using parity\n", ccd->ccd_unit);
+ error = EINVAL;
+ goto fail;
+ }
cs->sc_size = cs->sc_nccdisks * minsize;
+ }
}
/*
@@ -499,25 +551,36 @@ ccdinit(ccd, cpaths, p)
cs->sc_cflags = ccd->ccd_flags; /* So we can find out later... */
cs->sc_unit = ccd->ccd_unit;
return (0);
+fail:
+ while (ci > cs->sc_cinfo) {
+ ci--;
+ free(ci->ci_path, M_DEVBUF);
+ }
+ free(cs->sc_cinfo, M_DEVBUF);
+ return (error);
}
static void
ccdinterleave(cs, unit)
- register struct ccd_softc *cs;
+ struct ccd_softc *cs;
int unit;
{
- register struct ccdcinfo *ci, *smallci;
- register struct ccdiinfo *ii;
- register daddr_t bn, lbn;
- register int ix;
+ struct ccdcinfo *ci, *smallci;
+ struct ccdiinfo *ii;
+ daddr_t bn, lbn;
+ int ix;
u_long size;
#ifdef DEBUG
if (ccddebug & CCDB_INIT)
printf("ccdinterleave(%x): ileave %d\n", cs, cs->sc_ileave);
#endif
+
/*
- * Allocate an interleave table.
+ * Allocate an interleave table. The worst case occurs when each
+ * of N disks is of a different size, resulting in N interleave
+ * tables.
+ *
* Chances are this is too big, but we don't care.
*/
size = (cs->sc_nccdisks + 1) * sizeof(struct ccdiinfo);
@@ -527,6 +590,8 @@ ccdinterleave(cs, unit)
/*
* Trivial case: no interleave (actually interleave of disk size).
* Each table entry represents a single component in its entirety.
+ *
+ * An interleave of 0 may not be used with a mirror or parity setup.
*/
if (cs->sc_ileave == 0) {
bn = 0;
@@ -556,7 +621,10 @@ ccdinterleave(cs, unit)
size = 0;
bn = lbn = 0;
for (ii = cs->sc_itable; ; ii++) {
- /* Allocate space for ii_index. */
+ /*
+ * Allocate space for ii_index. We might allocate more then
+ * we use.
+ */
ii->ii_index = malloc((sizeof(int) * cs->sc_nccdisks),
M_DEVBUF, M_WAITOK);
@@ -564,12 +632,14 @@ ccdinterleave(cs, unit)
* Locate the smallest of the remaining components
*/
smallci = NULL;
- for (ci = cs->sc_cinfo;
- ci < &cs->sc_cinfo[cs->sc_nccdisks]; ci++)
+ for (ci = cs->sc_cinfo; ci < &cs->sc_cinfo[cs->sc_nccdisks];
+ ci++) {
if (ci->ci_size > size &&
(smallci == NULL ||
- ci->ci_size < smallci->ci_size))
+ ci->ci_size < smallci->ci_size)) {
smallci = ci;
+ }
+ }
/*
* Nobody left, all done
@@ -580,9 +650,15 @@ ccdinterleave(cs, unit)
}
/*
- * Record starting logical block and component offset
+ * Record starting logical block using an sc_ileave blocksize.
*/
ii->ii_startblk = bn / cs->sc_ileave;
+
+ /*
+ * Record starting comopnent block using an sc_ileave
+ * blocksize. This value is relative to the beginning of
+ * a component disk.
+ */
ii->ii_startoff = lbn;
/*
@@ -590,10 +666,12 @@ ccdinterleave(cs, unit)
* and record their indices.
*/
ix = 0;
- for (ci = cs->sc_cinfo;
- ci < &cs->sc_cinfo[cs->sc_nccdisks]; ci++)
- if (ci->ci_size >= smallci->ci_size)
+ for (ci = cs->sc_cinfo;
+ ci < &cs->sc_cinfo[cs->sc_nccdisks]; ci++) {
+ if (ci->ci_size >= smallci->ci_size) {
ii->ii_index[ix++] = ci - cs->sc_cinfo;
+ }
+ }
ii->ii_ndisk = ix;
bn += ix * (smallci->ci_size - size);
lbn = smallci->ci_size / cs->sc_ileave;
@@ -710,11 +788,11 @@ ccdclose(dev, flags, fmt, p)
static void
ccdstrategy(bp)
- register struct buf *bp;
+ struct buf *bp;
{
- register int unit = ccdunit(bp->b_dev);
- register struct ccd_softc *cs = &ccd_softc[unit];
- register int s;
+ int unit = ccdunit(bp->b_dev);
+ struct ccd_softc *cs = &ccd_softc[unit];
+ int s;
int wlabel;
struct disklabel *lp;
@@ -758,10 +836,10 @@ done:
static void
ccdstart(cs, bp)
- register struct ccd_softc *cs;
- register struct buf *bp;
+ struct ccd_softc *cs;
+ struct buf *bp;
{
- register long bcount, rcount;
+ long bcount, rcount;
struct ccdbuf *cbp[4];
/* XXX! : 2 reads and 2 writes for RAID 4/5 */
caddr_t addr;
@@ -792,14 +870,44 @@ ccdstart(cs, bp)
for (bcount = bp->b_bcount; bcount > 0; bcount -= rcount) {
ccdbuffer(cbp, cs, bp, bn, addr, bcount);
rcount = cbp[0]->cb_buf.b_bcount;
- if ((cbp[0]->cb_buf.b_flags & B_READ) == 0)
- cbp[0]->cb_buf.b_vp->v_numoutput++;
- VOP_STRATEGY(cbp[0]->cb_buf.b_vp, &cbp[0]->cb_buf);
- if (cs->sc_cflags & CCDF_MIRROR &&
- (cbp[0]->cb_buf.b_flags & B_READ) == 0) {
- /* mirror, start another write */
- cbp[1]->cb_buf.b_vp->v_numoutput++;
- VOP_STRATEGY(cbp[1]->cb_buf.b_vp, &cbp[1]->cb_buf);
+
+ if (cs->sc_cflags & CCDF_MIRROR) {
+ /*
+ * Mirroring. Writes go to both disks, reads are
+ * taken from whichever disk seems most appropriate.
+ *
+ * We attempt to localize reads to the disk whos arm
+ * is nearest the read request. We ignore seeks due
+ * to writes when making this determination and we
+ * also try to avoid hogging.
+ */
+ if ((cbp[0]->cb_buf.b_flags & B_READ) == 0) {
+ cbp[0]->cb_buf.b_vp->v_numoutput++;
+ cbp[1]->cb_buf.b_vp->v_numoutput++;
+ VOP_STRATEGY(cbp[0]->cb_buf.b_vp,
+ &cbp[0]->cb_buf);
+ VOP_STRATEGY(cbp[1]->cb_buf.b_vp,
+ &cbp[1]->cb_buf);
+ } else {
+ int pick = cs->sc_pick;
+ daddr_t range = cs->sc_size / 16;
+
+ if (bn < cs->sc_blk[pick] - range ||
+ bn > cs->sc_blk[pick] + range
+ ) {
+ cs->sc_pick = pick = 1 - pick;
+ }
+ cs->sc_blk[pick] = bn + btodb(rcount);
+ VOP_STRATEGY(cbp[pick]->cb_buf.b_vp,
+ &cbp[pick]->cb_buf);
+ }
+ } else {
+ /*
+ * Not mirroring
+ */
+ if ((cbp[0]->cb_buf.b_flags & B_READ) == 0)
+ cbp[0]->cb_buf.b_vp->v_numoutput++;
+ VOP_STRATEGY(cbp[0]->cb_buf.b_vp, &cbp[0]->cb_buf);
}
bn += btodb(rcount);
addr += rcount;
@@ -811,17 +919,17 @@ ccdstart(cs, bp)
*/
static void
ccdbuffer(cb, cs, bp, bn, addr, bcount)
- register struct ccdbuf **cb;
- register struct ccd_softc *cs;
+ struct ccdbuf **cb;
+ struct ccd_softc *cs;
struct buf *bp;
daddr_t bn;
caddr_t addr;
long bcount;
{
- register struct ccdcinfo *ci, *ci2 = NULL; /* XXX */
- register struct ccdbuf *cbp;
- register daddr_t cbn, cboff;
- register off_t cbc;
+ struct ccdcinfo *ci, *ci2 = NULL; /* XXX */
+ struct ccdbuf *cbp;
+ daddr_t cbn, cboff;
+ off_t cbc;
#ifdef DEBUG
if (ccddebug & CCDB_IO)
@@ -834,61 +942,108 @@ ccdbuffer(cb, cs, bp, bn, addr, bcount)
cbn = bn;
cboff = 0;
- /*
- * Serially concatenated
- */
if (cs->sc_ileave == 0) {
- register daddr_t sblk;
+ /*
+ * Serially concatenated and neither a mirror nor a parity
+ * config. This is a special case.
+ */
+ daddr_t sblk;
sblk = 0;
for (ci = cs->sc_cinfo; cbn >= sblk + ci->ci_size; ci++)
sblk += ci->ci_size;
cbn -= sblk;
- }
- /*
- * Interleaved
- */
- else {
- register struct ccdiinfo *ii;
+ } else {
+ struct ccdiinfo *ii;
int ccdisk, off;
- cboff = cbn % cs->sc_ileave;
- cbn /= cs->sc_ileave;
- for (ii = cs->sc_itable; ii->ii_ndisk; ii++)
+ /*
+ * Calculate cbn, the logical superblock (sc_ileave chunks),
+ * and cboff, a normal block offset (DEV_BSIZE chunks) relative
+ * to cbn.
+ */
+ cboff = cbn % cs->sc_ileave; /* DEV_BSIZE gran */
+ cbn = cbn / cs->sc_ileave; /* DEV_BSIZE * ileave gran */
+
+ /*
+ * Figure out which interleave table to use.
+ */
+ for (ii = cs->sc_itable; ii->ii_ndisk; ii++) {
if (ii->ii_startblk > cbn)
break;
+ }
ii--;
+
+ /*
+ * off is the logical superblock relative to the beginning
+ * of this interleave block.
+ */
off = cbn - ii->ii_startblk;
+
+ /*
+ * We must calculate which disk component to use (ccdisk),
+ * and recalculate cbn to be the superblock relative to
+ * the beginning of the component. This is typically done by
+ * adding 'off' and ii->ii_startoff together. However, 'off'
+ * must typically be divided by the number of components in
+ * this interleave array to be properly convert it from a
+ * CCD-relative logical superblock number to a
+ * component-relative superblock number.
+ */
if (ii->ii_ndisk == 1) {
+ /*
+ * When we have just one disk, it can't be a mirror
+ * or a parity config.
+ */
ccdisk = ii->ii_index[0];
cbn = ii->ii_startoff + off;
} else {
if (cs->sc_cflags & CCDF_MIRROR) {
- ccdisk = ii->ii_index[off % (ii->ii_ndisk/2)];
- cbn = ii->ii_startoff + off / (ii->ii_ndisk/2);
- /* mirrored data */
- ci2 = &cs->sc_cinfo[ccdisk + ii->ii_ndisk/2];
- }
- else if (cs->sc_cflags & CCDF_PARITY) {
- ccdisk = ii->ii_index[off % (ii->ii_ndisk-1)];
- cbn = ii->ii_startoff + off / (ii->ii_ndisk-1);
+ /*
+ * We have forced a uniform mapping, resulting
+ * in a single interleave array. We double
+ * up on the first half of the available
+ * components and our mirror is in the second
+ * half. This only works with a single
+ * interleave array because doubling up
+ * doubles the number of sectors, so there
+ * cannot be another interleave array because
+ * the next interleave array's calculations
+ * would be off.
+ */
+ int ndisk2 = ii->ii_ndisk / 2;
+ ccdisk = ii->ii_index[off % ndisk2];
+ cbn = ii->ii_startoff + off / ndisk2;
+ ci2 = &cs->sc_cinfo[ccdisk + ndisk2];
+ } else if (cs->sc_cflags & CCDF_PARITY) {
+ /*
+ * XXX not implemented yet
+ */
+ int ndisk2 = ii->ii_ndisk - 1;
+ ccdisk = ii->ii_index[off % ndisk2];
+ cbn = ii->ii_startoff + off / ndisk2;
if (cbn % ii->ii_ndisk <= ccdisk)
ccdisk++;
- }
- else {
+ } else {
ccdisk = ii->ii_index[off % ii->ii_ndisk];
cbn = ii->ii_startoff + off / ii->ii_ndisk;
}
}
- cbn *= cs->sc_ileave;
+
ci = &cs->sc_cinfo[ccdisk];
+
+ /*
+ * Convert cbn from a superblock to a normal block so it
+ * can be used to calculate (along with cboff) the normal
+ * block index into this particular disk.
+ */
+ cbn *= cs->sc_ileave;
}
/*
* Fill in the component buf structure.
*/
- cbp = getccdbuf();
- bzero(cbp, sizeof (struct ccdbuf));
+ cbp = getccdbuf(NULL);
cbp->cb_buf.b_flags = bp->b_flags | B_CALL;
cbp->cb_buf.b_iodone = (void (*)(struct buf *))ccdiodone;
cbp->cb_buf.b_dev = ci->ci_dev; /* XXX */
@@ -896,10 +1051,6 @@ ccdbuffer(cb, cs, bp, bn, addr, bcount)
cbp->cb_buf.b_offset = dbtob(cbn + cboff + CCD_OFFSET);
cbp->cb_buf.b_data = addr;
cbp->cb_buf.b_vp = ci->ci_vp;
- LIST_INIT(&cbp->cb_buf.b_dep);
- BUF_LOCKINIT(&cbp->cb_buf);
- BUF_LOCK(&cbp->cb_buf, LK_EXCLUSIVE);
- cbp->cb_buf.b_resid = 0;
if (cs->sc_ileave == 0)
cbc = dbtob((off_t)(ci->ci_size - cbn));
else
@@ -921,17 +1072,16 @@ ccdbuffer(cb, cs, bp, bn, addr, bcount)
cbp->cb_buf.b_data, cbp->cb_buf.b_bcount);
#endif
cb[0] = cbp;
- if (cs->sc_cflags & CCDF_MIRROR &&
- (cbp->cb_buf.b_flags & B_READ) == 0) {
- /* mirror, start one more write */
- cbp = getccdbuf();
- bzero(cbp, sizeof (struct ccdbuf));
- *cbp = *cb[0];
+
+ /*
+ * Note: both I/O's setup when reading from mirror, but only one
+ * will be executed.
+ */
+ if (cs->sc_cflags & CCDF_MIRROR) {
+ /* mirror, setup second I/O */
+ cbp = getccdbuf(cb[0]);
cbp->cb_buf.b_dev = ci2->ci_dev;
cbp->cb_buf.b_vp = ci2->ci_vp;
- LIST_INIT(&cbp->cb_buf.b_dep);
- BUF_LOCKINIT(&cbp->cb_buf);
- BUF_LOCK(&cbp->cb_buf, LK_EXCLUSIVE);
cbp->cb_comp = ci2 - cs->sc_cinfo;
cb[1] = cbp;
/* link together the ccdbuf's and clear "mirror done" flag */
@@ -944,8 +1094,8 @@ ccdbuffer(cb, cs, bp, bn, addr, bcount)
static void
ccdintr(cs, bp)
- register struct ccd_softc *cs;
- register struct buf *bp;
+ struct ccd_softc *cs;
+ struct buf *bp;
{
#ifdef DEBUG
if (ccddebug & CCDB_FOLLOW)
@@ -969,8 +1119,8 @@ static void
ccdiodone(cbp)
struct ccdbuf *cbp;
{
- register struct buf *bp = cbp->cb_obp;
- register int unit = cbp->cb_unit;
+ struct buf *bp = cbp->cb_obp;
+ int unit = cbp->cb_unit;
int count, s;
s = splbio();
@@ -986,27 +1136,87 @@ ccdiodone(cbp)
cbp->cb_buf.b_bcount);
}
#endif
+ /*
+ * If an error occured, report it. If this is a mirrored
+ * configuration and the first of two possible reads, do not
+ * set the error in the bp yet because the second read may
+ * succeed.
+ */
if (cbp->cb_buf.b_flags & B_ERROR) {
- bp->b_flags |= B_ERROR;
- bp->b_error = cbp->cb_buf.b_error ? cbp->cb_buf.b_error : EIO;
-#ifdef DEBUG
- printf("ccd%d: error %d on component %d\n",
- unit, bp->b_error, cbp->cb_comp);
-#endif
+ const char *msg = "";
+
+ if ((ccd_softc[unit].sc_cflags & CCDF_MIRROR) &&
+ (cbp->cb_buf.b_flags & B_READ) &&
+ (cbp->cb_pflags & CCDPF_MIRROR_DONE) == 0) {
+ /*
+ * We will try our read on the other disk down
+ * below, also reverse the default pick so if we
+ * are doing a scan we do not keep hitting the
+ * bad disk first.
+ */
+ struct ccd_softc *cs = &ccd_softc[unit];
+
+ msg = ", trying other disk";
+ cs->sc_pick = 1 - cs->sc_pick;
+ cs->sc_blk[cs->sc_pick] = bp->b_blkno;
+ } else {
+ bp->b_flags |= B_ERROR;
+ bp->b_error = cbp->cb_buf.b_error ?
+ cbp->cb_buf.b_error : EIO;
+ }
+ printf("ccd%d: error %d on component %d block %d (ccd block %d)%s\n",
+ unit, bp->b_error, cbp->cb_comp,
+ (int)cbp->cb_buf.b_blkno, bp->b_blkno, msg);
}
- if (ccd_softc[unit].sc_cflags & CCDF_MIRROR &&
- (cbp->cb_buf.b_flags & B_READ) == 0)
- if ((cbp->cb_pflags & CCDPF_MIRROR_DONE) == 0) {
- /* I'm done before my counterpart, so just set
- partner's flag and return */
- cbp->cb_mirror->cb_pflags |= CCDPF_MIRROR_DONE;
- putccdbuf(cbp);
- splx(s);
- return;
+ /*
+ * Process mirror. If we are writing, I/O has been initiated on both
+ * buffers and we fall through only after both are finished.
+ *
+ * If we are reading only one I/O is initiated at a time. If an
+ * error occurs we initiate the second I/O and return, otherwise
+ * we free the second I/O without initiating it.
+ */
+
+ if (ccd_softc[unit].sc_cflags & CCDF_MIRROR) {
+ if ((cbp->cb_buf.b_flags & B_READ) == 0) {
+ /*
+ * When writing, handshake with the second buffer
+ * to determine when both are done. If both are not
+ * done, return here.
+ */
+ if ((cbp->cb_pflags & CCDPF_MIRROR_DONE) == 0) {
+ cbp->cb_mirror->cb_pflags |= CCDPF_MIRROR_DONE;
+ putccdbuf(cbp);
+ splx(s);
+ return;
+ }
+ } else {
+ /*
+ * When reading, either dispose of the second buffer
+ * or initiate I/O on the second buffer if an error
+ * occured with this one.
+ */
+ if ((cbp->cb_pflags & CCDPF_MIRROR_DONE) == 0) {
+ if (cbp->cb_buf.b_flags & B_ERROR) {
+ cbp->cb_mirror->cb_pflags |=
+ CCDPF_MIRROR_DONE;
+ VOP_STRATEGY(
+ cbp->cb_mirror->cb_buf.b_vp,
+ &cbp->cb_mirror->cb_buf
+ );
+ putccdbuf(cbp);
+ splx(s);
+ return;
+ } else {
+ putccdbuf(cbp->cb_mirror);
+ /* fall through */
+ }
+ }
}
-
+ }
+
/*
* use b_bufsize to determine how big the original request was rather
* then b_bcount, because b_bcount may have been truncated for EOF.
@@ -1509,7 +1719,7 @@ static void
printiinfo(ii)
struct ccdiinfo *ii;
{
- register int ix, i;
+ int ix, i;
for (ix = 0; ii->ii_ndisk; ix++, ii++) {
printf(" itab[%d]: #dk %d sblk %d soff %d",
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