Whoops, sorry about the previous misfire...

I've got a program which attempts to read all blocks and may be able to rewrite bad blocks. It's nothing fancy. Only works if you've got auto-reallocate turned on in the drive.

% cat diskscan.c #include <stdio.h> #include <unistd.h> #include <errno.h> #include <fcntl.h>

int fixup(off, fd) off_t off; int fd; { char buffer[512]; int i, rval;

for (i = 0; i < 65536; i += 512) { if (lseek(fd, off + i, SEEK_SET) < 0) { doerror("lseek", off + i, 0); } if ((rval = read(fd, buffer, sizeof(buffer))) != sizeof(buffer)) { if (errno) { if (lseek(fd, off + i, SEEK_SET) < 0) { doerror("lseek", off + i, 0); } write(fd, buffer, sizeof(buffer)); } } } }

int doerror(str, off, type) char *str; off_t off; int type; { static int ign = 0; char buffer[80];

fprintf(stderr, "\nError at %qx, ", (quad_t) off); perror(str); if (! ign) { if (type) { fprintf(stderr, "Attempt to correct? (y/n/a) "); } else { fprintf(stderr, "Press 'y' to continue: "); } while (! ign) { fgets(buffer, sizeof(buffer), stdin); if (*buffer == 'y') { return(0); } if (*buffer == 'n') { return(1); } if (*buffer == 'a') { ign++; return(0); } } } return(0); }

int main(argc, argv) int argc; char *argv[]; { int fd, rval; char buffer[65536]; off_t off = 0; int eof = 0; int count = 0;

if (argc != 2) { fprintf(stderr, "usage: diskscan <dev>\n"); exit(1); } if ((fd = open(argv[1], O_RDWR, 0644)) < 0) { perror(argv[1]); } while (! eof) { if (! count) { fprintf(stderr, "%qx, ", (quad_t) off); } count++; count %= 8;

if (lseek(fd, off, SEEK_SET) < 0) { doerror("lseek", off, 0); } if ((rval = read(fd, buffer, sizeof(buffer))) != sizeof(buffer)) { if (errno) { if (! doerror("read", off, 1)) { fixup(off, fd); } } } off += sizeof(buffer); } }

I don't even guarantee that it's correct, but I do use it with some success... vinum takes an entire drive offline when it sees an error, and I use this to scan for and fix errors before turning the drive back on.

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