+
+/*
+ * Attempt to read a disk label from a device using the indicated stategy
+ * routine. The label must be partly set up before this: secpercyl and
+ * anything required in the strategy routine (e.g., sector size) must be
+ * filled in before calling us. Returns NULL on success and an error
+ * string on failure.
+ */
+char *
+readdisklabel(dev, strat, lp)
+ dev_t dev;
+ int (*strat)();
+ register struct disklabel *lp;
+{
+ register struct buf *bp;
+ struct disklabel *dlp;
+ char *msg = NULL;
+
+ if (lp->d_secperunit == 0)
+ lp->d_secperunit = 0x1fffffff;
+ lp->d_npartitions = 1;
+ if (lp->d_partitions[0].p_size == 0)
+ lp->d_partitions[0].p_size = 0x1fffffff;
+ lp->d_partitions[0].p_offset = 0;
+
+ bp = geteblk((int)lp->d_secsize);
+ bp->b_dev = dev;
+ bp->b_blkno = LABELSECTOR;
+ bp->b_bcount = lp->d_secsize;
+ bp->b_flags = B_BUSY | B_READ;
+ bp->b_cylin = LABELSECTOR / lp->d_secpercyl;
+ (*strat)(bp);
+ if (biowait(bp)) {
+ msg = "I/O error";
+ } else for (dlp = (struct disklabel *)bp->b_un.b_addr;
+ dlp <= (struct disklabel *)(bp->b_un.b_addr+DEV_BSIZE-sizeof(*dlp));
+ dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
+ if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) {
+ if (msg == NULL)
+ msg = "no disk label";
+ } else if (dlp->d_npartitions > MAXPARTITIONS ||
+ dkcksum(dlp) != 0)
+ msg = "disk label corrupted";
+ else {
+ *lp = *dlp;
+ msg = NULL;
+ break;
+ }
+ }
+ bp->b_flags = B_INVAL | B_AGE;
+ brelse(bp);
+ return (msg);
+}
+
+/*
+ * Check new disk label for sensibility before setting it.
+ */
+int
+setdisklabel(olp, nlp, openmask)
+ register struct disklabel *olp, *nlp;
+ u_long openmask;
+{
+ register i;
+ register struct partition *opp, *npp;
+
+ if (nlp->d_magic != DISKMAGIC || nlp->d_magic2 != DISKMAGIC ||
+ dkcksum(nlp) != 0)
+ return (EINVAL);
+ while ((i = ffs((long)openmask)) != 0) {
+ i--;
+ openmask &= ~(1 << i);
+ if (nlp->d_npartitions <= i)
+ return (EBUSY);
+ opp = &olp->d_partitions[i];
+ npp = &nlp->d_partitions[i];
+ if (npp->p_offset != opp->p_offset || npp->p_size < opp->p_size)
+ return (EBUSY);
+ /*
+ * Copy internally-set partition information
+ * if new label doesn't include it. XXX
+ */
+ if (npp->p_fstype == FS_UNUSED && opp->p_fstype != FS_UNUSED) {
+ npp->p_fstype = opp->p_fstype;
+ npp->p_fsize = opp->p_fsize;
+ npp->p_frag = opp->p_frag;
+ npp->p_cpg = opp->p_cpg;
+ }
+ }
+ nlp->d_checksum = 0;
+ nlp->d_checksum = dkcksum(nlp);
+ *olp = *nlp;
+ return (0);
+}
+
+/* encoding of disk minor numbers, should be elsewhere... */
+#define dkunit(dev) (minor(dev) >> 3)
+#define dkpart(dev) (minor(dev) & 07)
+#define dkminor(unit, part) (((unit) << 3) | (part))
+
+/*
+ * Write disk label back to device after modification.
+ */
+int
+writedisklabel(dev, strat, lp)
+ dev_t dev;
+ int (*strat)();
+ register struct disklabel *lp;
+{
+ struct buf *bp;
+ struct disklabel *dlp;
+ int labelpart;
+ int error = 0;
+
+ labelpart = dkpart(dev);
+ if (lp->d_partitions[labelpart].p_offset != 0) {
+ if (lp->d_partitions[0].p_offset != 0)
+ return (EXDEV); /* not quite right */
+ labelpart = 0;
+ }
+ bp = geteblk((int)lp->d_secsize);
+ bp->b_dev = makedev(major(dev), dkminor(dkunit(dev), labelpart));
+ bp->b_blkno = LABELSECTOR;
+ bp->b_bcount = lp->d_secsize;
+ bp->b_flags = B_READ;
+ (*strat)(bp);
+ if (error = biowait(bp))
+ goto done;
+ for (dlp = (struct disklabel *)bp->b_un.b_addr;
+ dlp <= (struct disklabel *)
+ (bp->b_un.b_addr + lp->d_secsize - sizeof(*dlp));
+ dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
+ if (dlp->d_magic == DISKMAGIC && dlp->d_magic2 == DISKMAGIC &&
+ dkcksum(dlp) == 0) {
+ *dlp = *lp;
+ bp->b_flags = B_WRITE;
+ (*strat)(bp);
+ error = biowait(bp);
+ goto done;
+ }
+ }
+ error = ESRCH;
+done:
+ brelse(bp);
+ return (error);
+}
+
+/*
+ * Compute checksum for disk label.
+ */
+dkcksum(lp)
+ register struct disklabel *lp;
+{
+ register u_short *start, *end;
+ register u_short sum = 0;
+
+ start = (u_short *)lp;
+ end = (u_short *)&lp->d_partitions[lp->d_npartitions];
+ while (start < end)
+ sum ^= *start++;
+ return (sum);
+}
+
+/*
+ * Disk error is the preface to plaintive error messages
+ * about failing disk transfers. It prints messages of the form
+
+hp0g: hard error reading fsbn 12345 of 12344-12347 (hp0 bn %d cn %d tn %d sn %d)
+
+ * if the offset of the error in the transfer and a disk label
+ * are both available. blkdone should be -1 if the position of the error
+ * is unknown; the disklabel pointer may be null from drivers that have not
+ * been converted to use them. The message is printed with printf
+ * if pri is LOG_PRINTF, otherwise it uses log at the specified priority.
+ * The message should be completed (with at least a newline) with printf
+ * or addlog, respectively. There is no trailing space.
+ */
+void
+diskerr(bp, dname, what, pri, blkdone, lp)
+ register struct buf *bp;
+ char *dname, *what;
+ int pri, blkdone;
+ register struct disklabel *lp;
+{
+ int unit = dkunit(bp->b_dev), part = dkpart(bp->b_dev);
+ register void (*pr) __P((const char *, ...));
+ char partname = 'a' + part;
+ int sn;
+
+ if (pri != LOG_PRINTF) {
+ log(pri, "");
+ pr = addlog;
+ } else
+ pr = printf;
+ (*pr)("%s%d%c: %s %sing fsbn ", dname, unit, partname, what,
+ bp->b_flags & B_READ ? "read" : "writ");
+ sn = bp->b_blkno;
+ if (bp->b_bcount <= DEV_BSIZE)
+ (*pr)("%d", sn);
+ else {
+ if (blkdone >= 0) {
+ sn += blkdone;
+ (*pr)("%d of ", sn);
+ }
+ (*pr)("%d-%d", bp->b_blkno,
+ bp->b_blkno + (bp->b_bcount - 1) / DEV_BSIZE);
+ }
+ if (lp && (blkdone >= 0 || bp->b_bcount <= lp->d_secsize)) {
+#ifdef tahoe
+ sn *= DEV_BSIZE / lp->d_secsize; /* XXX */
+#endif
+ sn += lp->d_partitions[part].p_offset;
+ (*pr)(" (%s%d bn %d; cn %d", dname, unit, sn,
+ sn / lp->d_secpercyl);
+ sn %= lp->d_secpercyl;
+ (*pr)(" tn %d sn %d)", sn / lp->d_nsectors, sn % lp->d_nsectors);
+ }
+}
projects / unix-history / blobdiff