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Add a new flag to dumpfs(8), -f, which causes dumpfs to list all free

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fragments in the file system by fragment (block) number.  This new
mode does the necessary arithmetic to generate absolute fragment
numbers rather than than the cg-relative numbers printed in the default
mode.

If -f is passed once, contiguous fragment ranges are collapsed into
an X-Y format as free block lists are currently printed in regular
dumpfs output, but if specified twice, all block numbers are printed
individually, allowing both compact and more script-friendly
representation.

This proves quite handy when attempting to recover deleted data, as it
allows exclusion of non-deleted data from blocks searched.
MFC after:	1 week
Discussed with:	jeff, Richard Clayton <richard dot clayton at cl.cam.ac.uk>
Sponsored by:	Google, Inc.
This commit is contained in:
Robert Watson 2009-01-28 09:33:00 +00:00
parent c27cd4240a
commit fd15d586ee
2 changed files with 82 additions and 7 deletions
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16
sbin/dumpfs/dumpfs.8
View File

@ -36,15 +36,18 @@
.Nd dump file system information
.Sh SYNOPSIS
.Nm
.Op Fl f
.Op Fl m
.Ar filesys | device
.Sh DESCRIPTION
The
.Nm
utility prints out the super block and cylinder group information
for the file system or special device specified, unless
for the file system or special device specified, unless the
.Fl f
or
.Fl m
is specified.
flag is specified.
The listing is very long and detailed.
This
command is useful mostly for finding out certain file system
@ -52,6 +55,15 @@ information such as the file system block size and minimum
free space percentage.
.Pp
If
.Fl f
is specified, a sorted list of all free fragments and free fragment ranges,
as represented in cylinder group block free lists, is printed.
If the flag is specified twice, contiguous free fragments are not collapsed
into ranges and instead printed in a simple list.
Fragment numbers may be converted to raw byte offsets by multiplying by the
fragment size, which may be useful when recovering deleted data.
.Pp
If
.Fl m
is specified, a
.Xr newfs 8

73
sbin/dumpfs/dumpfs.c
View File

@ -1,4 +1,10 @@
/*
* Copyright (c) 2009 Robert N. M. Watson
* All rights reserved.
*
* This software was developed at the University of Cambridge Computer
* Laboratory with support from a grant from Google, Inc.
*
* Copyright (c) 2002 Networks Associates Technology, Inc.
* All rights reserved.
*
@ -74,8 +80,11 @@ struct uufsd disk;
int dumpfs(const char *);
int dumpcg(void);
int dumpfreespace(const char *, int);
void dumpfreespacecg(int);
int marshal(const char *);
void pbits(void *, int);
void pblklist(void *, int, off_t, int);
void ufserr(const char *);
void usage(void) __dead2;
@ -83,12 +92,15 @@ int
main(int argc, char *argv[])
{
const char *name;
int ch, domarshal, eval;
int ch, dofreespace, domarshal, eval;
domarshal = eval = 0;
dofreespace = domarshal = eval = 0;
while ((ch = getopt(argc, argv, "m")) != -1) {
while ((ch = getopt(argc, argv, "fm")) != -1) {
switch (ch) {
case 'f':
dofreespace++;
break;
case 'm':
domarshal = 1;
break;
@ -102,6 +114,10 @@ main(int argc, char *argv[])
if (argc < 1)
usage();
if (dofreespace && domarshal)
usage();
if (dofreespace > 2)
usage();
while ((name = *argv++) != NULL) {
if (ufs_disk_fillout(&disk, name) == -1) {
@ -109,7 +125,9 @@ main(int argc, char *argv[])
eval |= 1;
continue;
}
if (domarshal)
if (dofreespace)
eval |= dumpfreespace(name, dofreespace);
else if (domarshal)
eval |= marshal(name);
else
eval |= dumpfs(name);
@ -332,6 +350,30 @@ dumpcg(void)
return (0);
}
int
dumpfreespace(const char *name, int fflag)
{
int i;
while ((i = cgread(&disk)) != 0) {
if (i == -1)
goto err;
dumpfreespacecg(fflag);
}
return (0);
err:
ufserr(name);
return (1);
}
void
dumpfreespacecg(int fflag)
{
pblklist(cg_blksfree(&acg), afs.fs_fpg, disk.d_lcg * afs.fs_fpg,
fflag);
}
int
marshal(const char *name)
{
@ -400,6 +442,27 @@ pbits(void *vp, int max)
printf("\n");
}
void
pblklist(void *vp, int max, off_t offset, int fflag)
{
int i, j;
char *p;
for (i = 0, p = vp; i < max; i++) {
if (isset(p, i)) {
printf("%jd", (intmax_t)(i + offset));
if (fflag < 2) {
j = i;
while ((i+1)<max && isset(p, i+1))
i++;
if (i != j)
printf("-%lld", i + offset);
}
printf("\n");
}
}
}
void
ufserr(const char *name)
{
@ -412,6 +475,6 @@ ufserr(const char *name)
void
usage(void)
{
(void)fprintf(stderr, "usage: dumpfs [-m] filesys | device\n");
(void)fprintf(stderr, "usage: dumpfs [-fm] filesys | device\n");
exit(1);
}