NetBSD/sbin/resize_ffs/resize_ffs.c
jtk ec57cc7eb3 Preliminary version of resize_ffs, based on der Mouse's fsresize tool.
I didn't have time to clean it up completely before my legal status
w.r.t. open source projects goes into limbo for a while.  Other
developers are encouraged to play with the tool and get it into
release-worthy shape.

TODO list (see TODO file)

* verify it builds on -current, put it into release lists/etc. and src/sbin/Makefile
  (built & tested on 1.6.1)
* make it ask questions before doing any work (confirm)
* create regression test suite (see discussions on tech-kern and
  developers) and fix any bugs
* verify conversion to ANSI C didn't break anything
* port to UFS2
2003-02-21 04:08:54 +00:00

1884 lines
55 KiB
C

/* $NetBSD: resize_ffs.c,v 1.1 2003/02/21 04:08:55 jtk Exp $ */
/* From sources sent on February 17, 2003 */
/*-
* As its sole author, I explicitly place this code in the public
* domain. Anyone may use it for any purpose (though I would
* appreciate credit where it is due).
*
* der Mouse
*
* mouse@rodents.montreal.qc.ca
* 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B
*/
/*
* ffs_resize:
*
* Resize a filesystem. Is capable of both growing and shrinking.
*
* Usage: fsresize filesystem newsize
*
* Example: fsresize /dev/rsd1e 29574
*
* newsize is in DEV_BSIZE units (ie, disk sectors, usually 512 bytes
* each).
*
* Note: this currently requires gcc to build, since it is written
* depending on gcc-specific features, notably nested function
* definitions (which in at least a few cases depend on the lexical
* scoping gcc provides, so they can't be trivially moved outside).
*
* It will not do anything useful with filesystems in other than
* host-native byte order. This really should be fixed (it's largely
* a historical accident; the original version of this program is
* older than bi-endian support in FFS).
*
* Many thanks go to John Kohl <jtk@netbsd.org> for finding bugs: the
* one responsible for the "realloccgblk: can't find blk in cyl"
* problem and a more minor one which left fs_dsize wrong when
* shrinking. (These actually indicate bugs in fsck too - it should
* have caught and fixed them.)
*
*/
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <strings.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/param.h> /* MAXFRAG */
#include <ufs/ufs/dinode.h> /* ufs_daddr_t */
#include <ufs/ffs/fs.h>
#include <ufs/ufs/dir.h>
#include <ufs/ufs/dinode.h>
#include <ufs/ufs/ufs_bswap.h> /* ufs_rw32 */
extern const char *__progname;
/* Patchup for systems that don't yet have __progname */
#ifdef NO_PROGNAME
const char *__progname;
int main(int, char **);
int main_(int, char **);
int
main(int ac, char **av)
#define main main_
{
__progname = av[0];
return (main(ac, av));
}
#endif
/* Suppress warnings about unused arguments */
#if defined(__GNUC__) && \
( (__GNUC__ > 2) || \
( (__GNUC__ == 2) && \
defined(__GNUC_MINOR__) && \
(__GNUC_MINOR__ >= 7) ) )
#define UNUSED_ARG(x) x __attribute__((__unused__))
#define INLINE inline
#else
#define UNUSED_ARG(x) x
#define INLINE /**/
#endif
/* new size of filesystem, in sectors */
static int newsize;
/* fd open onto disk device */
static int fd;
/* must we break up big I/O operations - see checksmallio() */
static int smallio;
/* size of a cg, in bytes, rounded up to a frag boundary */
static int cgblksz;
/* Superblocks. */
static struct fs *oldsb; /* before we started */
static struct fs *newsb; /* copy to work with */
/* Buffer to hold the above. Make sure it's aligned correctly. */
static char sbbuf[2 * SBSIZE] __attribute__((__aligned__(__alignof__(struct fs))));
/* a cg's worth of brand new squeaky-clean inodes */
static struct dinode *zinodes;
/* pointers to the in-core cgs, read off disk and possibly modified */
static struct cg **cgs;
/* pointer to csum array - the stuff pointed to on-disk by fs_csaddr */
static struct csum *csums;
/* per-cg flags, indexed by cg number */
static unsigned char *cgflags;
#define CGF_DIRTY 0x01 /* needs to be written to disk */
#define CGF_BLKMAPS 0x02 /* block bitmaps need rebuilding */
#define CGF_INOMAPS 0x04 /* inode bitmaps need rebuilding */
/* when shrinking, these two arrays record how we want blocks to move. */
/* if blkmove[i] is j, the frag that started out as frag #i should end */
/* up as frag #j. inomove[i]=j means, similarly, that the inode that */
/* started out as inode i should end up as inode j. */
static unsigned int *blkmove;
static unsigned int *inomove;
/* in-core copies of all inodes in the fs, indexed by inumber */
static struct dinode *inodes;
/* per-inode flags, indexed by inumber */
static unsigned char *iflags;
#define IF_DIRTY 0x01 /* needs to be written to disk */
#define IF_BDIRTY 0x02 /* like DIRTY, but is set on first inode in a
* block of inodes, and applies to the whole
* block. */
/*
* See if we need to break up large I/O operations. This should never
* be needed, but under at least one <version,platform> combination,
* large enough disk transfers to the raw device hang. So if we're
* talking to a character special device, play it safe; in this case,
* readat() and writeat() break everything up into pieces no larger
* than 8K, doing multiple syscalls for larger operations.
*/
static void
checksmallio(void)
{
struct stat stb;
fstat(fd, &stb);
smallio = ((stb.st_mode & S_IFMT) == S_IFCHR);
}
/*
* Read size bytes starting at blkno into buf. blkno is in DEV_BSIZE
* units, ie, after fsbtodb(); size is in bytes.
*/
static void
readat(off_t blkno, void *buf, int size)
{
/* Seek to the correct place. */
if (lseek(fd, blkno * DEV_BSIZE, L_SET) < 0) {
fprintf(stderr, "%s: lseek: %s\n", __progname,
strerror(errno));
exit(1);
}
/* See if we have to break up the transfer... */
if (smallio) {
char *bp; /* pointer into buf */
int left; /* bytes left to go */
int n; /* number to do this time around */
int rv; /* syscall return value */
bp = buf;
left = size;
while (left > 0) {
n = (left > 8192) ? 8192 : left;
rv = read(fd, bp, n);
if (rv < 0) {
fprintf(stderr, "%s: read: %s\n", __progname,
strerror(errno));
exit(1);
}
if (rv != n) {
fprintf(stderr,
"%s: read: wanted %d, got %d\n",
__progname, n, rv);
exit(1);
}
bp += n;
left -= n;
}
} else {
int rv;
rv = read(fd, buf, size);
if (rv < 0) {
fprintf(stderr, "%s: read: %s\n", __progname,
strerror(errno));
exit(1);
}
if (rv != size) {
fprintf(stderr, "%s: read: wanted %d, got %d\n",
__progname, size, rv);
exit(1);
}
}
}
/*
* Write size bytes from buf starting at blkno. blkno is in DEV_BSIZE
* units, ie, after fsbtodb(); size is in bytes.
*/
static void
writeat(off_t blkno, const void *buf, int size)
{
/* Seek to the correct place. */
if (lseek(fd, blkno * DEV_BSIZE, L_SET) < 0) {
fprintf(stderr, "%s: lseek: %s\n", __progname,
strerror(errno));
exit(1);
}
/* See if we have to break up the transfer... */
if (smallio) {
const char *bp; /* pointer into buf */
int left; /* bytes left to go */
int n; /* number to do this time around */
int rv; /* syscall return value */
bp = buf;
left = size;
while (left > 0) {
n = (left > 8192) ? 8192 : left;
rv = write(fd, bp, n);
if (rv < 0) {
fprintf(stderr, "%s: write: %s\n", __progname,
strerror(errno));
exit(1);
}
if (rv != n) {
fprintf(stderr,
"%s: write: wanted %d, got %d\n",
__progname, n, rv);
exit(1);
}
bp += n;
left -= n;
}
} else {
int rv;
rv = write(fd, buf, size);
if (rv < 0) {
fprintf(stderr, "%s: write: %s\n", __progname,
strerror(errno));
exit(1);
}
if (rv != size) {
fprintf(stderr, "%s: write: wanted %d, got %d\n",
__progname, size, rv);
exit(1);
}
}
}
/*
* Never-fail versions of malloc() and realloc(), and an allocation
* routine (which also never fails) for allocating memory that will
* never be freed until exit.
*/
/*
* Never-fail malloc.
*/
static void *
nfmalloc(size_t nb, const char *tag)
{
void *rv;
rv = malloc(nb);
if (rv)
return (rv);
fprintf(stderr, "%s: can't allocate %lu bytes for %s\n",
__progname, (unsigned long int) nb, tag);
exit(1);
}
/*
* Never-fail realloc.
*/
static void *
nfrealloc(void *blk, size_t nb, const char *tag)
{
void *rv;
rv = realloc(blk, nb);
if (rv)
return (rv);
fprintf(stderr, "%s: can't reallocate to %lu bytes for %s\n",
__progname, (unsigned long int) nb, tag);
exit(1);
}
/*
* Allocate memory that will never be freed or reallocated. Arguably
* this routine should handle small allocations by chopping up pages,
* but that's not worth the bother; it's not called more than a
* handful of times per run, and if the allocations are that small the
* waste in giving each one its own page is ignorable.
*/
static void *
alloconce(size_t nb, const char *tag)
{
void *rv;
rv = mmap(0, nb, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0);
if (rv != MAP_FAILED)
return (rv);
fprintf(stderr, "%s: can't allocate %lu bytes for %s\n", __progname,
(unsigned long int) nb, tag);
exit(1);
}
/*
* Load the cgs and csums off disk. Also allocates the space to load
* them into and initializes the per-cg flags.
*/
static void
loadcgs(void)
{
int cg;
char *cgp;
cgblksz = roundup(oldsb->fs_cgsize, oldsb->fs_fsize);
cgs = nfmalloc(oldsb->fs_ncg * sizeof(struct cg *), "cg pointers");
cgp = alloconce(oldsb->fs_ncg * cgblksz, "cgs");
cgflags = nfmalloc(oldsb->fs_ncg, "cg flags");
csums = nfmalloc(oldsb->fs_cssize, "cg summary");
for (cg = 0; cg < oldsb->fs_ncg; cg++) {
cgs[cg] = (struct cg *) cgp;
readat(fsbtodb(oldsb, cgtod(oldsb, cg)), cgp, cgblksz);
cgflags[cg] = 0;
cgp += cgblksz;
}
readat(fsbtodb(oldsb, oldsb->fs_csaddr), csums, oldsb->fs_cssize);
}
/*
* Set n bits, starting with bit #base, in the bitmap pointed to by
* bitvec (which is assumed to be large enough to include bits base
* through base+n-1).
*/
static void
set_bits(unsigned char *bitvec, unsigned int base, unsigned int n)
{
if (n < 1)
return; /* nothing to do */
if (base & 7) { /* partial byte at beginning */
if (n <= 8 - (base & 7)) { /* entirely within one byte */
bitvec[base >> 3] |= (~((~0U) << n)) << (base & 7);
return;
}
bitvec[base >> 3] |= (~0U) << (base & 7);
n -= 8 - (base & 7);
base = (base & ~7) + 8;
}
if (n >= 8) { /* do full bytes */
memset(bitvec + (base >> 3), 0xff, n >> 3);
base += n & ~7;
n &= 7;
}
if (n) { /* partial byte at end */
bitvec[base >> 3] |= ~((~0U) << n);
}
}
/*
* Clear n bits, starting with bit #base, in the bitmap pointed to by
* bitvec (which is assumed to be large enough to include bits base
* through base+n-1). Code parallels set_bits().
*/
static void
clr_bits(unsigned char *bitvec, int base, int n)
{
if (n < 1)
return;
if (base & 7) {
if (n <= 8 - (base & 7)) {
bitvec[base >> 3] &= ~((~((~0U) << n)) << (base & 7));
return;
}
bitvec[base >> 3] &= ~((~0U) << (base & 7));
n -= 8 - (base & 7);
base = (base & ~7) + 8;
}
if (n >= 8) {
bzero(bitvec + (base >> 3), n >> 3);
base += n & ~7;
n &= 7;
}
if (n) {
bitvec[base >> 3] &= (~0U) << n;
}
}
/*
* Test whether bit #bit is set in the bitmap pointed to by bitvec.
*/
INLINE static int
bit_is_set(unsigned char *bitvec, int bit)
{
return (bitvec[bit >> 3] & (1 << (bit & 7)));
}
/*
* Test whether bit #bit is clear in the bitmap pointed to by bitvec.
*/
INLINE static int
bit_is_clr(unsigned char *bitvec, int bit)
{
return (!bit_is_set(bitvec, bit));
}
/*
* Test whether a whole block of bits is set in a bitmap. This is
* designed for testing (aligned) disk blocks in a bit-per-frag
* bitmap; it has assumptions wired into it based on that, essentially
* that the entire block fits into a single byte. This returns true
* iff _all_ the bits are set; it is not just the complement of
* blk_is_clr on the same arguments (unless blkfrags==1).
*/
INLINE static int
blk_is_set(unsigned char *bitvec, int blkbase, int blkfrags)
{
unsigned int mask;
mask = (~((~0U) << blkfrags)) << (blkbase & 7);
return ((bitvec[blkbase >> 3] & mask) == mask);
}
/*
* Test whether a whole block of bits is clear in a bitmap. See
* blk_is_set (above) for assumptions. This returns true iff _all_
* the bits are clear; it is not just the complement of blk_is_set on
* the same arguments (unless blkfrags==1).
*/
INLINE static int
blk_is_clr(unsigned char *bitvec, int blkbase, int blkfrags)
{
unsigned int mask;
mask = (~((~0U) << blkfrags)) << (blkbase & 7);
return ((bitvec[blkbase >> 3] & mask) == 0);
}
/*
* Initialize a new cg. Called when growing. Assumes memory has been
* allocated but not otherwise set up. This code sets the fields of
* the cg, initializes the bitmaps (and cluster summaries, if
* applicable), updates both per-cylinder summary info and the global
* summary info in newsb; it also writes out new inodes for the cg.
*
* This code knows it can never be called for cg 0, which makes it a
* bit simpler than it would otherwise be.
*/
static void
initcg(int cgn)
{
struct cg *cg; /* The in-core cg, of course */
int base; /* Disk address of cg base */
int dlow; /* Size of pre-cg data area */
int dhigh; /* Offset of post-inode data area, from base */
int dmax; /* Offset of end of post-inode data area */
int i; /* Generic loop index */
int n; /* Generic count */
cg = cgs[cgn];
/* Place the data areas */
base = cgbase(newsb, cgn);
dlow = cgsblock(newsb, cgn) - base;
dhigh = cgdmin(newsb, cgn) - base;
dmax = newsb->fs_size - base;
if (dmax > newsb->fs_fpg)
dmax = newsb->fs_fpg;
/*
* Clear out the cg - assumes all-0-bytes is the correct way
* to initialize fields we don't otherwise touch, which is
* perhaps not the right thing to do, but it's what fsck and
* mkfs do.
*/
bzero(cg, newsb->fs_cgsize);
cg->cg_time = newsb->fs_time;
cg->cg_magic = CG_MAGIC;
cg->cg_cgx = cgn;
cg->cg_ncyl = newsb->fs_cpg;
/* fsck whines if the cg->cg_ncyl value in the last cg is fs_cpg
* instead of zero, when fs_cpg is the correct value. */
/* XXX fix once fsck is fixed */
if ((cgn == newsb->fs_ncg - 1) /* && (newsb->fs_ncyl % newsb->fs_cpg) */ ) {
cg->cg_ncyl = newsb->fs_ncyl % newsb->fs_cpg;
}
cg->cg_niblk = newsb->fs_ipg;
cg->cg_ndblk = dmax;
/* Set up the bitmap pointers. We have to be careful to lay out the
* cg _exactly_ the way mkfs and fsck do it, since fsck compares the
* _entire_ cg against a recomputed cg, and whines if there is any
* mismatch, including the bitmap offsets. */
/* XXX update this comment when fsck is fixed */
cg->cg_btotoff = &cg->cg_space[0] - (unsigned char *) cg;
cg->cg_boff = cg->cg_btotoff + (newsb->fs_cpg * sizeof(int32_t));
cg->cg_iusedoff = cg->cg_boff +
(newsb->fs_cpg * newsb->fs_nrpos * sizeof(int16_t));
cg->cg_freeoff = cg->cg_iusedoff + howmany(newsb->fs_ipg, NBBY);
if (newsb->fs_contigsumsize > 0) {
cg->cg_nclusterblks = cg->cg_ndblk / newsb->fs_frag;
cg->cg_clustersumoff = cg->cg_freeoff +
howmany(newsb->fs_cpg * newsb->fs_spc / NSPF(newsb),
NBBY) - sizeof(int32_t);
cg->cg_clustersumoff =
roundup(cg->cg_clustersumoff, sizeof(int32_t));
cg->cg_clusteroff = cg->cg_clustersumoff +
((newsb->fs_contigsumsize + 1) * sizeof(int32_t));
cg->cg_nextfreeoff = cg->cg_clusteroff +
howmany(newsb->fs_cpg * newsb->fs_spc / NSPB(newsb),
NBBY);
n = dlow / newsb->fs_frag;
if (n > 0) {
set_bits(cg_clustersfree(cg, 0), 0, n);
cg_clustersum(cg, 0)[(n > newsb->fs_contigsumsize) ?
newsb->fs_contigsumsize : n]++;
}
} else {
cg->cg_nextfreeoff = cg->cg_freeoff +
howmany(newsb->fs_cpg * newsb->fs_spc / NSPF(newsb),
NBBY);
}
/* Mark the data areas as free; everything else is marked busy by the
* bzero up at the top. */
set_bits(cg_blksfree(cg, 0), 0, dlow);
set_bits(cg_blksfree(cg, 0), dhigh, dmax - dhigh);
/* Initialize summary info */
cg->cg_cs.cs_ndir = 0;
cg->cg_cs.cs_nifree = newsb->fs_ipg;
cg->cg_cs.cs_nbfree = dlow / newsb->fs_frag;
cg->cg_cs.cs_nffree = 0;
/* This is the simplest way of doing this; we perhaps could compute
* the correct cg_blktot()[] and cg_blks()[] values other ways, but it
* would be complicated and hardly seems worth the effort. (The
* reason there isn't frag-at-beginning and frag-at-end code here,
* like the code below for the post-inode data area, is that the
* pre-sb data area always starts at 0, and thus is block-aligned, and
* always ends at the sb, which is block-aligned.) */
for (i = 0; i < dlow; i += newsb->fs_frag) {
cg_blktot(cg, 0)[cbtocylno(newsb, i)]++;
cg_blks(newsb, cg, cbtocylno(newsb, i), 0)[cbtorpos(newsb, i)]++;
}
/* Deal with a partial block at the beginning of the post-inode area.
* I'm not convinced this can happen - I think the inodes are always
* block-aligned and always an integral number of blocks - but it's
* cheap to do the right thing just in case. */
if (dhigh % newsb->fs_frag) {
n = newsb->fs_frag - (dhigh % newsb->fs_frag);
cg->cg_frsum[n]++;
cg->cg_cs.cs_nffree += n;
dhigh += n;
}
n = (dmax - dhigh) / newsb->fs_frag;
/* We have n full-size blocks in the post-inode data area. */
if (n > 0) {
cg->cg_cs.cs_nbfree += n;
if (newsb->fs_contigsumsize > 0) {
i = dhigh / newsb->fs_frag;
set_bits(cg_clustersfree(cg, 0), i, n);
cg_clustersum(cg, 0)[(n > newsb->fs_contigsumsize) ?
newsb->fs_contigsumsize : n]++;
}
for (i = n; i > 0; i--) {
cg_blktot(cg, 0)[cbtocylno(newsb, dhigh)]++;
cg_blks(newsb, cg,
cbtocylno(newsb, dhigh), 0)[cbtorpos(newsb,
dhigh)]++;
dhigh += newsb->fs_frag;
}
}
/* Deal with any leftover frag at the end of the cg. */
i = dmax - dhigh;
if (i) {
cg->cg_frsum[i]++;
cg->cg_cs.cs_nffree += i;
}
/* Update the csum info. */
csums[cgn] = cg->cg_cs;
newsb->fs_cstotal.cs_nffree += cg->cg_cs.cs_nffree;
newsb->fs_cstotal.cs_nbfree += cg->cg_cs.cs_nbfree;
newsb->fs_cstotal.cs_nifree += cg->cg_cs.cs_nifree;
/* Write out the cleared inodes. */
writeat(fsbtodb(newsb, cgimin(newsb, cgn)), zinodes,
newsb->fs_ipg * sizeof(struct dinode));
/* Dirty the cg. */
cgflags[cgn] |= CGF_DIRTY;
}
/*
* Find free space, at least nfrags consecutive frags of it. Pays no
* attention to block boundaries, but refuses to straddle cg
* boundaries, even if the disk blocks involved are in fact
* consecutive. Return value is the frag number of the first frag of
* the block, or -1 if no space was found. Uses newsb for sb values,
* and assumes the cgs[] structures correctly describe the area to be
* searched.
*
* XXX is there a bug lurking in the ignoring of block boundaries by
* the routine used by fragmove() in evict_data()? Can an end-of-file
* frag legally straddle a block boundary? If not, this should be
* cloned and fixed to stop at block boundaries for that use. The
* current one may still be needed for csum info motion, in case that
* takes up more than a whole block (is the csum info allowed to begin
* partway through a block and continue into the following block?).
*
* If we wrap off the end of the filesystem back to the beginning, we
* can end up searching the end of the filesystem twice. I ignore
* this inefficiency, since if that happens we're going to croak with
* a no-space error anyway, so it happens at most once.
*/
static int
find_freespace(unsigned int nfrags)
{
static int hand = 0; /* hand rotates through all frags in the fs */
int cgsize; /* size of the cg hand currently points into */
int cgn; /* number of cg hand currently points into */
int fwc; /* frag-within-cg number of frag hand points
* to */
int run; /* length of run of free frags seen so far */
int secondpass; /* have we wrapped from end of fs to
* beginning? */
unsigned char *bits; /* cg_blksfree()[] for cg hand points into */
cgn = dtog(newsb, hand);
fwc = dtogd(newsb, hand);
secondpass = (hand == 0);
run = 0;
bits = cg_blksfree(cgs[cgn], 0);
cgsize = cgs[cgn]->cg_ndblk;
while (1) {
if (bit_is_set(bits, fwc)) {
run++;
if (run >= nfrags)
return (hand + 1 - run);
} else {
run = 0;
}
hand++;
fwc++;
if (fwc >= cgsize) {
fwc = 0;
cgn++;
if (cgn >= newsb->fs_ncg) {
hand = 0;
if (secondpass)
return (-1);
secondpass = 1;
cgn = 0;
}
bits = cg_blksfree(cgs[cgn], 0);
cgsize = cgs[cgn]->cg_ndblk;
run = 0;
}
}
}
/*
* Find a free block of disk space. Finds an entire block of frags,
* all of which are free. Return value is the frag number of the
* first frag of the block, or -1 if no space was found. Uses newsb
* for sb values, and assumes the cgs[] structures correctly describe
* the area to be searched.
*
* See find_freespace(), above, for remarks about hand wrapping around.
*/
static int
find_freeblock(void)
{
static int hand = 0; /* hand rotates through all frags in fs */
int cgn; /* cg number of cg hand points into */
int fwc; /* frag-within-cg number of frag hand points
* to */
int cgsize; /* size of cg hand points into */
int secondpass; /* have we wrapped from end to beginning? */
unsigned char *bits; /* cg_blksfree()[] for cg hand points into */
cgn = dtog(newsb, hand);
fwc = dtogd(newsb, hand);
secondpass = (hand == 0);
bits = cg_blksfree(cgs[cgn], 0);
cgsize = blknum(newsb, cgs[cgn]->cg_ndblk);
while (1) {
if (blk_is_set(bits, fwc, newsb->fs_frag))
return (hand);
fwc += newsb->fs_frag;
hand += newsb->fs_frag;
if (fwc >= cgsize) {
fwc = 0;
cgn++;
if (cgn >= newsb->fs_ncg) {
hand = 0;
if (secondpass)
return (-1);
secondpass = 1;
cgn = 0;
}
bits = cg_blksfree(cgs[cgn], 0);
cgsize = blknum(newsb, cgs[cgn]->cg_ndblk);
}
}
}
/*
* Find a free inode, returning its inumber or -1 if none was found.
* Uses newsb for sb values, and assumes the cgs[] structures
* correctly describe the area to be searched.
*
* See find_freespace(), above, for remarks about hand wrapping around.
*/
static int
find_freeinode(void)
{
static int hand = 0; /* hand rotates through all inodes in fs */
int cgn; /* cg number of cg hand points into */
int iwc; /* inode-within-cg number of inode hand points
* to */
int secondpass; /* have we wrapped from end to beginning? */
unsigned char *bits; /* cg_inosused()[] for cg hand points into */
cgn = hand / newsb->fs_ipg;
iwc = hand % newsb->fs_ipg;
secondpass = (hand == 0);
bits = cg_inosused(cgs[cgn], 0);
while (1) {
if (bit_is_clr(bits, iwc))
return (hand);
hand++;
iwc++;
if (iwc >= newsb->fs_ipg) {
iwc = 0;
cgn++;
if (cgn >= newsb->fs_ncg) {
hand = 0;
if (secondpass)
return (-1);
secondpass = 1;
cgn = 0;
}
bits = cg_inosused(cgs[cgn], 0);
}
}
}
/*
* Mark a frag as free. Sets the frag's bit in the cg_blksfree bitmap
* for the appropriate cg, and marks the cg as dirty.
*/
static void
free_frag(int fno)
{
int cgn;
cgn = dtog(newsb, fno);
set_bits(cg_blksfree(cgs[cgn], 0), dtogd(newsb, fno), 1);
cgflags[cgn] |= CGF_DIRTY | CGF_BLKMAPS;
}
/*
* Allocate a frag. Clears the frag's bit in the cg_blksfree bitmap
* for the appropriate cg, and marks the cg as dirty.
*/
static void
alloc_frag(int fno)
{
int cgn;
cgn = dtog(newsb, fno);
clr_bits(cg_blksfree(cgs[cgn], 0), dtogd(newsb, fno), 1);
cgflags[cgn] |= CGF_DIRTY | CGF_BLKMAPS;
}
/*
* Fix up the csum array. If shrinking, this involves freeing zero or
* more frags; if growing, it involves allocating them, or if the
* frags being grown into aren't free, finding space elsewhere for the
* csum info. (If the number of occupied frags doesn't change,
* nothing happens here.)
*/
static void
csum_fixup(void)
{
int nold; /* # frags in old csum info */
int ntot; /* # frags in new csum info */
int nnew; /* ntot-nold */
int newloc; /* new location for csum info, if necessary */
int i; /* generic loop index */
int j; /* generic loop index */
int f; /* "from" frag number, if moving */
int t; /* "to" frag number, if moving */
int cgn; /* cg number, used when shrinking */
ntot = howmany(newsb->fs_cssize, newsb->fs_fsize);
nold = howmany(oldsb->fs_cssize, newsb->fs_fsize);
nnew = ntot - nold;
/* First, if there's no change in frag counts, it's easy. */
if (nnew == 0)
return;
/* Next, if we're shrinking, it's almost as easy. Just free up any
* frags in the old area we no longer need. */
if (nnew < 0) {
for ((i = newsb->fs_csaddr + ntot - 1), (j = nnew);
j < 0;
i--, j++) {
free_frag(i);
}
return;
}
/* We must be growing. Check to see that the new csum area fits
* within the filesystem. I think this can never happen, since for
* the csum area to grow, we must be adding at least one cg, so the
* old csum area can't be this close to the end of the new filesystem.
* But it's a cheap check. */
/* XXX what if csum info is at end of cg and grows into next cg, what
* if it spills over onto the next cg's backup superblock? Can this
* happen? */
if (newsb->fs_csaddr + ntot <= newsb->fs_size) {
/* Okay, it fits - now, see if the space we want is free. */
for ((i = newsb->fs_csaddr + nold), (j = nnew);
j > 0;
i++, j--) {
cgn = dtog(newsb, i);
if (bit_is_clr(cg_blksfree(cgs[cgn], 0),
dtogd(newsb, i)))
break;
}
if (j <= 0) {
/* Win win - all the frags we want are free. Allocate
* 'em and we're all done. */
for ((i = newsb->fs_csaddr + ntot - nnew), (j = nnew); j > 0; i++, j--) {
alloc_frag(i);
}
return;
}
}
/* We have to move the csum info, sigh. Look for new space, free old
* space, and allocate new. Update fs_csaddr. We don't copy anything
* on disk at this point; the csum info will be written to the
* then-current fs_csaddr as part of the final flush. */
newloc = find_freespace(ntot);
if (newloc < 0) {
printf("Sorry, no space available for new csums\n");
exit(1);
}
for (i = 0, f = newsb->fs_csaddr, t = newloc; i < ntot; i++, f++, t++) {
if (i < nold) {
free_frag(f);
}
alloc_frag(t);
}
newsb->fs_csaddr = newloc;
}
/*
* Recompute newsb->fs_dsize. Just scans all cgs, adding the number of
* data blocks in that cg to the total.
*/
static void
recompute_fs_dsize(void)
{
int i;
newsb->fs_dsize = 0;
for (i = 0; i < newsb->fs_ncg; i++) {
int dlow; /* size of before-sb data area */
int dhigh; /* offset of post-inode data area */
int dmax; /* total size of cg */
int base; /* base of cg, since cgsblock() etc add it in */
base = cgbase(newsb, i);
dlow = cgsblock(newsb, i) - base;
dhigh = cgdmin(newsb, i) - base;
dmax = newsb->fs_size - base;
if (dmax > newsb->fs_fpg)
dmax = newsb->fs_fpg;
newsb->fs_dsize += dlow + dmax - dhigh;
}
/* Space in cg 0 before cgsblock is boot area, not free space! */
newsb->fs_dsize -= cgsblock(newsb, 0) - cgbase(newsb, 0);
/* And of course the csum info takes up space. */
newsb->fs_dsize -= howmany(newsb->fs_cssize, newsb->fs_fsize);
}
/*
* Return the current time. We call this and assign, rather than
* calling time() directly, as insulation against OSes where fs_time
* is not a time_t.
*/
static time_t
timestamp(void)
{
time_t t;
time(&t);
return (t);
}
/*
* Grow the filesystem.
*/
static void
grow(void)
{
int i;
/* Update the timestamp. */
newsb->fs_time = timestamp();
/* Allocate and clear the new-inode area, in case we add any cgs. */
zinodes = alloconce(newsb->fs_ipg * sizeof(struct dinode),
"zeroed inodes");
bzero(zinodes, newsb->fs_ipg * sizeof(struct dinode));
/* Update the size. */
newsb->fs_size = dbtofsb(newsb, newsize);
/* Did we actually not grow? (This can happen if newsize is less than
* a frag larger than the old size - unlikely, but no excuse to
* misbehave if it happens.) */
if (newsb->fs_size == oldsb->fs_size)
return;
/* Check that the new last sector (frag, actually) is writable. Since
* it's at least one frag larger than it used to be, we know we aren't
* overwriting anything important by this. (The choice of sbbuf as
* what to write is irrelevant; it's just something handy that's known
* to be at least one frag in size.) */
writeat(newsb->fs_size - 1, &sbbuf, newsb->fs_fsize);
/* Update fs_ncyl and fs_ncg. */
newsb->fs_ncyl = (newsb->fs_size * NSPF(newsb)) / newsb->fs_spc;
newsb->fs_ncg = howmany(newsb->fs_ncyl, newsb->fs_cpg);
/* Does the last cg end before the end of its inode area? There is no
* reason why this couldn't be handled, but it would complicate a lot
* of code (in all filesystem code - fsck, kernel, etc) because of the
* potential partial inode area, and the gain in space would be
* minimal, at most the pre-sb data area. */
if (cgdmin(newsb, newsb->fs_ncg - 1) > newsb->fs_size) {
newsb->fs_ncg--;
newsb->fs_ncyl = newsb->fs_ncg * newsb->fs_cpg;
newsb->fs_size = (newsb->fs_ncyl * newsb->fs_spc) / NSPF(newsb);
printf("Warning: last cylinder group is too small;\n");
printf(" dropping it. New size = %lu.\n",
(unsigned long int) fsbtodb(newsb, newsb->fs_size));
}
/* Find out how big the csum area is, and realloc csums if bigger. */
newsb->fs_cssize = fragroundup(newsb,
newsb->fs_ncg * sizeof(struct csum));
if (newsb->fs_cssize > oldsb->fs_cssize)
csums = nfrealloc(csums, newsb->fs_cssize, "new cg summary");
/* If we're adding any cgs, realloc structures and set up the new cgs. */
if (newsb->fs_ncg > oldsb->fs_ncg) {
char *cgp;
cgs = nfrealloc(cgs, newsb->fs_ncg * sizeof(struct cg *),
"cg pointers");
cgflags = nfrealloc(cgflags, newsb->fs_ncg, "cg flags");
bzero(cgflags + oldsb->fs_ncg, newsb->fs_ncg - oldsb->fs_ncg);
cgp = alloconce((newsb->fs_ncg - oldsb->fs_ncg) * cgblksz,
"cgs");
for (i = oldsb->fs_ncg; i < newsb->fs_ncg; i++) {
cgs[i] = (struct cg *) cgp;
initcg(i);
cgp += cgblksz;
}
cgs[oldsb->fs_ncg - 1]->cg_ncyl = oldsb->fs_cpg;
cgflags[oldsb->fs_ncg - 1] |= CGF_DIRTY;
}
/* If the old fs ended partway through a cg, we have to update the old
* last cg (though possibly not to a full cg!). */
if (oldsb->fs_size % oldsb->fs_fpg) {
struct cg *cg;
int newcgsize;
int prevcgtop;
int oldcgsize;
cg = cgs[oldsb->fs_ncg - 1];
cgflags[oldsb->fs_ncg - 1] |= CGF_DIRTY | CGF_BLKMAPS;
prevcgtop = oldsb->fs_fpg * (oldsb->fs_ncg - 1);
newcgsize = newsb->fs_size - prevcgtop;
if (newcgsize > newsb->fs_fpg)
newcgsize = newsb->fs_fpg;
oldcgsize = oldsb->fs_size % oldsb->fs_fpg;
set_bits(cg_blksfree(cg, 0), oldcgsize, newcgsize - oldcgsize);
cg->cg_ncyl = howmany(newcgsize * NSPF(newsb), newsb->fs_spc);
cg->cg_ndblk = newcgsize;
}
/* Fix up the csum info, if necessary. */
csum_fixup();
/* Make fs_dsize match the new reality. */
recompute_fs_dsize();
}
/*
* Call (*fn)() for each inode, passing the inode and its inumber. The
* number of cylinder groups is pased in, so this can be used to map
* over either the old or the new filesystem's set of inodes.
*/
static void
map_inodes(void (*fn) (struct dinode * di, unsigned int, void *arg), int ncg, void *cbarg) {
int i;
int ni;
ni = oldsb->fs_ipg * ncg;
for (i = 0; i < ni; i++)
(*fn) (inodes + i, i, cbarg);
}
/* Values for the third argument to the map function for
* map_inode_data_blocks. MDB_DATA indicates the block is contains
* file data; MDB_INDIR_PRE and MDB_INDIR_POST indicate that it's an
* indirect block. The MDB_INDIR_PRE call is made before the indirect
* block pointers are followed and the pointed-to blocks scanned,
* MDB_INDIR_POST after.
*/
#define MDB_DATA 1
#define MDB_INDIR_PRE 2
#define MDB_INDIR_POST 3
typedef void (*mark_callback_t) (unsigned int blocknum, unsigned int nfrags, unsigned int blksize, int opcode);
/* Helper function - handles a data block. Calls the callback
* function and returns number of bytes occupied in file (actually,
* rounded up to a frag boundary). The name is historical. */
static int
markblk(mark_callback_t fn, struct dinode * di, int bn, off_t o)
{
int sz;
int nb;
if (o >= di->di_size)
return (0);
sz = dblksize(newsb, di, lblkno(newsb, o));
nb = (sz > di->di_size - o) ? di->di_size - o : sz;
if (bn)
(*fn) (bn, numfrags(newsb, sz), nb, MDB_DATA);
return (sz);
}
/* Helper function - handles an indirect block. Makes the
* MDB_INDIR_PRE callback for the indirect block, loops over the
* pointers and recurses, and makes the MDB_INDIR_POST callback.
* Returns the number of bytes occupied in file, as does markblk().
* For the sake of update_for_data_move(), we read the indirect block
* _after_ making the _PRE callback. The name is historical. */
static int
markiblk(mark_callback_t fn, struct dinode * di, int bn, off_t o, int lev)
{
int i;
int j;
int tot;
static daddr_t indirblk1[howmany(MAXBSIZE, sizeof(daddr_t))];
static daddr_t indirblk2[howmany(MAXBSIZE, sizeof(daddr_t))];
static daddr_t indirblk3[howmany(MAXBSIZE, sizeof(daddr_t))];
static daddr_t *indirblks[3] = {
&indirblk1[0], &indirblk2[0], &indirblk3[0]
};
if (lev < 0)
return (markblk(fn, di, bn, o));
if (bn == 0) {
for (i = newsb->fs_bsize;
lev >= 0;
i *= NINDIR(newsb), lev--);
return (i);
}
(*fn) (bn, newsb->fs_frag, newsb->fs_bsize, MDB_INDIR_PRE);
readat(fsbtodb(newsb, bn), indirblks[lev], newsb->fs_bsize);
tot = 0;
for (i = 0; i < NINDIR(newsb); i++) {
j = markiblk(fn, di, indirblks[lev][i], o, lev - 1);
if (j == 0)
break;
o += j;
tot += j;
}
(*fn) (bn, newsb->fs_frag, newsb->fs_bsize, MDB_INDIR_POST);
return (tot);
}
/*
* Call (*fn)() for each data block for an inode. This routine assumes
* the inode is known to be of a type that has data blocks (file,
* directory, or non-fast symlink). The called function is:
*
* (*fn)(unsigned int blkno, unsigned int nf, unsigned int nb, int op)
*
* where blkno is the frag number, nf is the number of frags starting
* at blkno (always <= fs_frag), nb is the number of bytes that belong
* to the file (usually nf*fs_frag, often less for the last block/frag
* of a file).
*/
static void
map_inode_data_blocks(struct dinode * di, mark_callback_t fn)
{
off_t o; /* offset within inode */
int inc; /* increment for o - maybe should be off_t? */
int b; /* index within di_db[] and di_ib[] arrays */
/* Scan the direct blocks... */
o = 0;
for (b = 0; b < NDADDR; b++) {
inc = markblk(fn, di, di->di_db[b], o);
if (inc == 0)
break;
o += inc;
}
/* ...and the indirect blocks. */
if (inc) {
for (b = 0; b < NIADDR; b++) {
inc = markiblk(fn, di, di->di_ib[b], o, b);
if (inc == 0)
return;
o += inc;
}
}
}
static void
dblk_callback(struct dinode * di, unsigned int inum, void *arg)
{
mark_callback_t fn;
fn = (mark_callback_t) arg;
switch (di->di_mode & IFMT) {
case IFLNK:
if (di->di_size > newsb->fs_maxsymlinklen) {
case IFDIR:
case IFREG:
map_inode_data_blocks(di, fn);
}
break;
}
}
/*
* Make a callback call, a la map_inode_data_blocks, for all data
* blocks in the entire fs. This is used only once, in
* update_for_data_move, but it's out at top level because the complex
* downward-funarg nesting that would otherwise result seems to give
* gcc gastric distress.
*/
static void
map_data_blocks(mark_callback_t fn, int ncg)
{
map_inodes(&dblk_callback, ncg, (void *) fn);
}
/*
* Initialize the blkmove array.
*/
static void
blkmove_init(void)
{
int i;
blkmove = alloconce(oldsb->fs_size * sizeof(*blkmove), "blkmove");
for (i = 0; i < oldsb->fs_size; i++)
blkmove[i] = i;
}
/*
* Load the inodes off disk. Allocates the structures and initializes
* them - the inodes from disk, the flags to zero.
*/
static void
loadinodes(void)
{
int cg;
struct dinode *iptr;
inodes = alloconce(oldsb->fs_ncg * oldsb->fs_ipg * sizeof(struct dinode), "inodes");
iflags = alloconce(oldsb->fs_ncg * oldsb->fs_ipg, "inode flags");
bzero(iflags, oldsb->fs_ncg * oldsb->fs_ipg);
iptr = inodes;
for (cg = 0; cg < oldsb->fs_ncg; cg++) {
readat(fsbtodb(oldsb, cgimin(oldsb, cg)), iptr,
oldsb->fs_ipg * sizeof(struct dinode));
iptr += oldsb->fs_ipg;
}
}
/*
* Report a filesystem-too-full problem.
*/
static void
toofull(void)
{
printf("Sorry, would run out of data blocks\n");
exit(1);
}
/*
* Record a desire to move "n" frags from "from" to "to".
*/
static void
mark_move(unsigned int from, unsigned int to, unsigned int n)
{
for (; n > 0; n--)
blkmove[from++] = to++;
}
/* Helper function - evict n frags, starting with start (cg-relative).
* The free bitmap is scanned, unallocated frags are ignored, and
* each block of consecutive allocated frags is moved as a unit.
*/
static void
fragmove(struct cg * cg, int base, unsigned int start, unsigned int n)
{
int i;
int run;
run = 0;
for (i = 0; i <= n; i++) {
if ((i < n) && bit_is_clr(cg_blksfree(cg, 0), start + i)) {
run++;
} else {
if (run > 0) {
int off;
off = find_freespace(run);
if (off < 0)
toofull();
mark_move(base + start + i - run, off, run);
set_bits(cg_blksfree(cg, 0), start + i - run,
run);
clr_bits(cg_blksfree(cgs[dtog(oldsb, off)], 0),
dtogd(oldsb, off), run);
}
run = 0;
}
}
}
/*
* Evict all data blocks from the given cg, starting at minfrag (based
* at the beginning of the cg), for length nfrag. The eviction is
* assumed to be entirely data-area; this should not be called with a
* range overlapping the metadata structures in the cg. It also
* assumes minfrag points into the given cg; it will misbehave if this
* is not true.
*
* See the comment header on find_freespace() for one possible bug
* lurking here.
*/
static void
evict_data(struct cg * cg, unsigned int minfrag, unsigned int nfrag)
{
int base; /* base of cg (in frags from beginning of fs) */
base = cgbase(oldsb, cg->cg_cgx);
/* Does the boundary fall in the middle of a block? To avoid breaking
* between frags allocated as consecutive, we always evict the whole
* block in this case, though one could argue we should check to see
* if the frag before or after the break is unallocated. */
if (minfrag % oldsb->fs_frag) {
int n;
n = minfrag % oldsb->fs_frag;
minfrag -= n;
nfrag += n;
}
/* Do whole blocks. If a block is wholly free, skip it; if wholly
* allocated, move it in toto. If neither, call fragmove() to move
* the frags to new locations. */
while (nfrag >= oldsb->fs_frag) {
if (!blk_is_set(cg_blksfree(cg, 0), minfrag, oldsb->fs_frag)) {
if (blk_is_clr(cg_blksfree(cg, 0), minfrag,
oldsb->fs_frag)) {
int off;
off = find_freeblock();
if (off < 0)
toofull();
mark_move(base + minfrag, off, oldsb->fs_frag);
set_bits(cg_blksfree(cg, 0), minfrag,
oldsb->fs_frag);
clr_bits(cg_blksfree(cgs[dtog(oldsb, off)], 0),
dtogd(oldsb, off), oldsb->fs_frag);
} else {
fragmove(cg, base, minfrag, oldsb->fs_frag);
}
}
minfrag += oldsb->fs_frag;
nfrag -= oldsb->fs_frag;
}
/* Clean up any sub-block amount left over. */
if (nfrag) {
fragmove(cg, base, minfrag, nfrag);
}
}
/*
* Move all data blocks according to blkmove. We have to be careful,
* because we may be updating indirect blocks that will themselves be
* getting moved, or inode daddr_t arrays that point to indirect
* blocks that will be moved. We call this before
* update_for_data_move, and update_for_data_move does inodes first,
* then indirect blocks in preorder, so as to make sure that the
* filesystem is self-consistent at all points, for better crash
* tolerance. (We can get away with this only because all the writes
* done by perform_data_move() are writing into space that's not used
* by the old filesystem.) If we crash, some things may point to the
* old data and some to the new, but both copies are the same. The
* only wrong things should be csum info and free bitmaps, which fsck
* is entirely capable of cleaning up.
*
* Since blkmove_init() initializes all blocks to move to their current
* locations, we can have two blocks marked as wanting to move to the
* same location, but only two and only when one of them is the one
* that was already there. So if blkmove[i]==i, we ignore that entry
* entirely - for unallocated blocks, we don't want it (and may be
* putting something else there), and for allocated blocks, we don't
* want to copy it anywhere.
*/
static void
perform_data_move(void)
{
int i;
int run;
int maxrun;
char buf[65536];
maxrun = sizeof(buf) / newsb->fs_fsize;
run = 0;
for (i = 0; i < oldsb->fs_size; i++) {
if ((blkmove[i] == i) ||
(run >= maxrun) ||
((run > 0) &&
(blkmove[i] != blkmove[i - 1] + 1))) {
if (run > 0) {
readat(fsbtodb(oldsb, i - run), &buf[0],
run << oldsb->fs_fshift);
writeat(fsbtodb(oldsb, blkmove[i - run]),
&buf[0], run << oldsb->fs_fshift);
}
run = 0;
}
if (blkmove[i] != i)
run++;
}
if (run > 0) {
readat(fsbtodb(oldsb, i - run), &buf[0],
run << oldsb->fs_fshift);
writeat(fsbtodb(oldsb, blkmove[i - run]), &buf[0],
run << oldsb->fs_fshift);
}
}
/*
* This modifies an array of daddr_t, according to blkmove. This is
* used to update inode block arrays and indirect blocks to point to
* the new locations of data blocks.
*
* Return value is the number of daddr_ts that needed updating; in
* particular, the return value is zero iff nothing was modified.
*/
static int
movemap_blocks(daddr_t * vec, int n)
{
int rv;
rv = 0;
for (; n > 0; n--, vec++) {
if (blkmove[*vec] != *vec) {
*vec = blkmove[*vec];
rv++;
}
}
return (rv);
}
static void
moveblocks_callback(struct dinode * di, unsigned int inum, void *arg)
{
switch (di->di_mode & IFMT) {
case IFLNK:
if (di->di_size > oldsb->fs_maxsymlinklen) {
case IFDIR:
case IFREG:
/* don't || these two calls; we need their
* side-effects */
if (movemap_blocks(&di->di_db[0], NDADDR)) {
iflags[inum] |= IF_DIRTY;
}
if (movemap_blocks(&di->di_ib[0], NIADDR)) {
iflags[inum] |= IF_DIRTY;
}
}
break;
}
}
static void
moveindir_callback(unsigned int off, unsigned int nfrag, unsigned int nbytes, int kind)
{
if (kind == MDB_INDIR_PRE) {
daddr_t blk[howmany(MAXBSIZE, sizeof(daddr_t))];
readat(fsbtodb(oldsb, off), &blk[0], oldsb->fs_bsize);
if (movemap_blocks(&blk[0], NINDIR(oldsb))) {
writeat(fsbtodb(oldsb, off), &blk[0], oldsb->fs_bsize);
}
}
}
/*
* Update all inode data arrays and indirect blocks to point to the new
* locations of data blocks. See the comment header on
* perform_data_move for some ordering considerations.
*/
static void
update_for_data_move(void)
{
map_inodes(&moveblocks_callback, oldsb->fs_ncg, NULL);
map_data_blocks(&moveindir_callback, oldsb->fs_ncg);
}
/*
* Initialize the inomove array.
*/
static void
inomove_init(void)
{
int i;
inomove = alloconce(oldsb->fs_ipg * oldsb->fs_ncg * sizeof(*inomove),
"inomove");
for (i = (oldsb->fs_ipg * oldsb->fs_ncg) - 1; i >= 0; i--)
inomove[i] = i;
}
/*
* Flush all dirtied inodes to disk. Scans the inode flags array; for
* each dirty inode, it sets the BDIRTY bit on the first inode in the
* block containing the dirty inode. Then it scans by blocks, and for
* each marked block, writes it.
*/
static void
flush_inodes(void)
{
int i;
int ni;
int m;
ni = newsb->fs_ipg * newsb->fs_ncg;
m = INOPB(newsb) - 1;
for (i = 0; i < ni; i++) {
if (iflags[i] & IF_DIRTY) {
iflags[i & ~m] |= IF_BDIRTY;
}
}
m++;
for (i = 0; i < ni; i += m) {
if (iflags[i] & IF_BDIRTY) {
writeat(fsbtodb(newsb, ino_to_fsba(newsb, i)),
inodes + i, newsb->fs_bsize);
}
}
}
/*
* Evict all inodes from the specified cg. shrink() already checked
* that there were enough free inodes, so the no-free-inodes check is
* a can't-happen. If it does trip, the filesystem should be in good
* enough shape for fsck to fix; see the comment on perform_data_move
* for the considerations in question.
*/
static void
evict_inodes(struct cg * cg)
{
int inum;
int i;
int fi;
inum = newsb->fs_ipg * cg->cg_cgx;
for (i = 0; i < newsb->fs_ipg; i++, inum++) {
if (inodes[inum].di_mode != 0) {
fi = find_freeinode();
if (fi < 0) {
printf("Sorry, inodes evaporated - "
"filesystem probably needs fsck\n");
exit(1);
}
inomove[inum] = fi;
clr_bits(cg_inosused(cg, 0), i, 1);
set_bits(cg_inosused(cgs[ino_to_cg(newsb, fi)], 0),
fi % newsb->fs_ipg, 1);
}
}
}
/*
* Move inodes from old locations to new. Does not actually write
* anything to disk; just copies in-core and sets dirty bits.
*
* We have to be careful here for reasons similar to those mentioned in
* the comment header on perform_data_move, above: for the sake of
* crash tolerance, we want to make sure everything is present at both
* old and new locations before we update pointers. So we call this
* first, then flush_inodes() to get them out on disk, then update
* directories to match.
*/
static void
perform_inode_move(void)
{
int i;
int ni;
ni = oldsb->fs_ipg * oldsb->fs_ncg;
for (i = 0; i < ni; i++) {
if (inomove[i] != i) {
inodes[inomove[i]] = inodes[i];
iflags[inomove[i]] = iflags[i] | IF_DIRTY;
}
}
}
/*
* Update the directory contained in the nb bytes at buf, to point to
* inodes' new locations.
*/
static int
update_dirents(char *buf, int nb)
{
int rv;
#define d ((struct direct *)buf)
rv = 0;
while (nb > 0) {
if (inomove[d->d_ino] != d->d_ino) {
rv++;
d->d_ino = inomove[d->d_ino];
}
nb -= d->d_reclen;
buf += d->d_reclen;
}
return (rv);
#undef d
}
/*
* Callback function for map_inode_data_blocks, for updating a
* directory to point to new inode locations.
*/
static void
update_dir_data(unsigned int bn, unsigned int size, unsigned int nb, int kind)
{
if (kind == MDB_DATA) {
union {
struct direct d;
char ch[MAXBSIZE];
} buf;
readat(fsbtodb(oldsb, bn), &buf, size << oldsb->fs_fshift);
if (update_dirents((char *) &buf, nb)) {
writeat(fsbtodb(oldsb, bn), &buf,
size << oldsb->fs_fshift);
}
}
}
static void
dirmove_callback(struct dinode * di, unsigned int inum, void *arg)
{
switch (di->di_mode & IFMT) {
case IFDIR:
map_inode_data_blocks(di, &update_dir_data);
break;
}
}
/*
* Update directory entries to point to new inode locations.
*/
static void
update_for_inode_move(void)
{
map_inodes(&dirmove_callback, newsb->fs_ncg, NULL);
}
/*
* Shrink the filesystem.
*/
static void
shrink(void)
{
int i;
/* Load the inodes off disk - we'll need 'em. */
loadinodes();
/* Update the timestamp. */
newsb->fs_time = timestamp();
/* Update the size figures. */
newsb->fs_size = dbtofsb(newsb, newsize);
newsb->fs_ncyl = (newsb->fs_size * NSPF(newsb)) / newsb->fs_spc;
newsb->fs_ncg = howmany(newsb->fs_ncyl, newsb->fs_cpg);
/* Does the (new) last cg end before the end of its inode area? See
* the similar code in grow() for more on this. */
if (cgdmin(newsb, newsb->fs_ncg - 1) > newsb->fs_size) {
newsb->fs_ncg--;
newsb->fs_ncyl = newsb->fs_ncg * newsb->fs_cpg;
newsb->fs_size = (newsb->fs_ncyl * newsb->fs_spc) / NSPF(newsb);
printf("Warning: last cylinder group is too small;\n");
printf(" dropping it. New size = %lu.\n",
(unsigned long int) fsbtodb(newsb, newsb->fs_size));
}
/* Let's make sure we're not being shrunk into oblivion. */
if (newsb->fs_ncg < 1) {
printf("Size too small - filesystem would have no cylinders\n");
exit(1);
}
/* Initialize for block motion. */
blkmove_init();
/* Update csum size, then fix up for the new size */
newsb->fs_cssize = fragroundup(newsb,
newsb->fs_ncg * sizeof(struct csum));
csum_fixup();
/* Evict data from any cgs being wholly eliminiated */
for (i = newsb->fs_ncg; i < oldsb->fs_ncg; i++) {
int base;
int dlow;
int dhigh;
int dmax;
base = cgbase(oldsb, i);
dlow = cgsblock(oldsb, i) - base;
dhigh = cgdmin(oldsb, i) - base;
dmax = oldsb->fs_size - base;
if (dmax > cgs[i]->cg_ndblk)
dmax = cgs[i]->cg_ndblk;
evict_data(cgs[i], 0, dlow);
evict_data(cgs[i], dhigh, dmax - dhigh);
newsb->fs_cstotal.cs_ndir -= cgs[i]->cg_cs.cs_ndir;
newsb->fs_cstotal.cs_nifree -= cgs[i]->cg_cs.cs_nifree;
newsb->fs_cstotal.cs_nffree -= cgs[i]->cg_cs.cs_nffree;
newsb->fs_cstotal.cs_nbfree -= cgs[i]->cg_cs.cs_nbfree;
}
/* Update the new last cg. */
cgs[newsb->fs_ncg - 1]->cg_ndblk = newsb->fs_size -
((newsb->fs_ncg - 1) * newsb->fs_fpg);
/* Is the new last cg partial? If so, evict any data from the part
* being shrunken away. */
if (newsb->fs_size % newsb->fs_fpg) {
struct cg *cg;
int oldcgsize;
int newcgsize;
cg = cgs[newsb->fs_ncg - 1];
newcgsize = newsb->fs_size % newsb->fs_fpg;
oldcgsize = oldsb->fs_size - ((newsb->fs_ncg - 1) & oldsb->fs_fpg);
if (oldcgsize > oldsb->fs_fpg)
oldcgsize = oldsb->fs_fpg;
evict_data(cg, newcgsize, oldcgsize - newcgsize);
clr_bits(cg_blksfree(cg, 0), newcgsize, oldcgsize - newcgsize);
}
/* Find out whether we would run out of inodes. (Note we haven't
* actually done anything to the filesystem yet; all those evict_data
* calls just update blkmove.) */
{
int slop;
slop = 0;
for (i = 0; i < newsb->fs_ncg; i++)
slop += cgs[i]->cg_cs.cs_nifree;
for (; i < oldsb->fs_ncg; i++)
slop -= oldsb->fs_ipg - cgs[i]->cg_cs.cs_nifree;
if (slop < 0) {
printf("Sorry, would run out of inodes\n");
exit(1);
}
}
/* Copy data, then update pointers to data. See the comment header on
* perform_data_move for ordering considerations. */
perform_data_move();
update_for_data_move();
/* Now do inodes. Initialize, evict, move, update - see the comment
* header on perform_inode_move. */
inomove_init();
for (i = newsb->fs_ncg; i < oldsb->fs_ncg; i++)
evict_inodes(cgs[i]);
perform_inode_move();
flush_inodes();
update_for_inode_move();
/* Recompute all the bitmaps; most of them probably need it anyway,
* the rest are just paranoia and not wanting to have to bother
* keeping track of exactly which ones require it. */
for (i = 0; i < newsb->fs_ncg; i++)
cgflags[i] |= CGF_DIRTY | CGF_BLKMAPS | CGF_INOMAPS;
/* Update the cg_ncyl value for the last cylinder. The condition is
* commented out because fsck whines if not - see the similar
* condition in grow() for more. */
/* XXX fix once fsck is fixed */
/* if (newsb->fs_ncyl % newsb->fs_cpg) XXX */
/*XXXJTK*/
cgs[newsb->fs_ncg - 1]->cg_ncyl =
newsb->fs_ncyl % newsb->fs_cpg;
/* Make fs_dsize match the new reality. */
recompute_fs_dsize();
}
/*
* Recompute the block totals, block cluster summaries, and rotational
* position summaries, for a given cg (specified by number), based on
* its free-frag bitmap (cg_blksfree()[]).
*/
static void
rescan_blkmaps(int cgn)
{
struct cg *cg;
int f;
int b;
int blkfree;
int blkrun;
int fragrun;
int fwb;
cg = cgs[cgn];
/* Subtract off the current totals from the sb's summary info */
newsb->fs_cstotal.cs_nffree -= cg->cg_cs.cs_nffree;
newsb->fs_cstotal.cs_nbfree -= cg->cg_cs.cs_nbfree;
/* Clear counters and bitmaps. */
cg->cg_cs.cs_nffree = 0;
cg->cg_cs.cs_nbfree = 0;
bzero(&cg->cg_frsum[0], MAXFRAG * sizeof(cg->cg_frsum[0]));
bzero(&cg_blktot(cg, 0)[0],
newsb->fs_cpg * sizeof(cg_blktot(cg, 0)[0]));
bzero(&cg_blks(newsb, cg, 0, 0)[0],
newsb->fs_cpg * newsb->fs_nrpos *
sizeof(cg_blks(newsb, cg, 0, 0)[0]));
if (newsb->fs_contigsumsize > 0) {
cg->cg_nclusterblks = cg->cg_ndblk / newsb->fs_frag;
bzero(&cg_clustersum(cg, 0)[1],
newsb->fs_contigsumsize *
sizeof(cg_clustersum(cg, 0)[1]));
bzero(&cg_clustersfree(cg, 0)[0],
howmany((newsb->fs_cpg * newsb->fs_spc) / NSPB(newsb),
NBBY));
}
/* Scan the free-frag bitmap. Runs of free frags are kept track of
* with fragrun, and recorded into cg_frsum[] and cg_cs.cs_nffree; on
* each block boundary, entire free blocks are recorded as well. */
blkfree = 1;
blkrun = 0;
fragrun = 0;
f = 0;
b = 0;
fwb = 0;
while (f < cg->cg_ndblk) {
if (bit_is_set(cg_blksfree(cg, 0), f)) {
fragrun++;
} else {
blkfree = 0;
if (fragrun > 0) {
cg->cg_frsum[fragrun]++;
cg->cg_cs.cs_nffree += fragrun;
}
fragrun = 0;
}
f++;
fwb++;
if (fwb >= newsb->fs_frag) {
if (blkfree) {
cg->cg_cs.cs_nbfree++;
if (newsb->fs_contigsumsize > 0)
set_bits(cg_clustersfree(cg, 0), b, 1);
cg_blktot(cg, 0)[cbtocylno(newsb, f - newsb->fs_frag)]++;
cg_blks(newsb, cg,
cbtocylno(newsb, f - newsb->fs_frag),
0)[cbtorpos(newsb, f - newsb->fs_frag)]++;
blkrun++;
} else {
if (fragrun > 0) {
cg->cg_frsum[fragrun]++;
cg->cg_cs.cs_nffree += fragrun;
}
if (newsb->fs_contigsumsize > 0) {
if (blkrun > 0) {
cg_clustersum(cg, 0)[(blkrun > newsb->fs_contigsumsize) ? newsb->fs_contigsumsize : blkrun]++;
}
}
blkrun = 0;
}
fwb = 0;
b++;
blkfree = 1;
fragrun = 0;
}
}
if (fragrun > 0) {
cg->cg_frsum[fragrun]++;
cg->cg_cs.cs_nffree += fragrun;
}
if ((blkrun > 0) && (newsb->fs_contigsumsize > 0)) {
cg_clustersum(cg, 0)[(blkrun > newsb->fs_contigsumsize) ?
newsb->fs_contigsumsize : blkrun]++;
}
/*
* Put the updated summary info back into csums, and add it
* back into the sb's summary info. Then mark the cg dirty.
*/
csums[cgn] = cg->cg_cs;
newsb->fs_cstotal.cs_nffree += cg->cg_cs.cs_nffree;
newsb->fs_cstotal.cs_nbfree += cg->cg_cs.cs_nbfree;
cgflags[cgn] |= CGF_DIRTY;
}
/*
* Recompute the cg_inosused()[] bitmap, and the cs_nifree and cs_ndir
* values, for a cg, based on the in-core inodes for that cg.
*/
static void
rescan_inomaps(int cgn)
{
struct cg *cg;
int inum;
int iwc;
cg = cgs[cgn];
newsb->fs_cstotal.cs_ndir -= cg->cg_cs.cs_ndir;
newsb->fs_cstotal.cs_nifree -= cg->cg_cs.cs_nifree;
cg->cg_cs.cs_ndir = 0;
cg->cg_cs.cs_nifree = 0;
bzero(&cg_inosused(cg, 0)[0], howmany(newsb->fs_ipg, NBBY));
inum = cgn * newsb->fs_ipg;
if (cgn == 0) {
set_bits(cg_inosused(cg, 0), 0, 2);
iwc = 2;
inum += 2;
} else {
iwc = 0;
}
for (; iwc < newsb->fs_ipg; iwc++, inum++) {
switch (inodes[inum].di_mode & IFMT) {
case 0:
cg->cg_cs.cs_nifree++;
break;
case IFDIR:
cg->cg_cs.cs_ndir++;
/* fall through */
default:
set_bits(cg_inosused(cg, 0), iwc, 1);
break;
}
}
csums[cgn] = cg->cg_cs;
newsb->fs_cstotal.cs_ndir += cg->cg_cs.cs_ndir;
newsb->fs_cstotal.cs_nifree += cg->cg_cs.cs_nifree;
cgflags[cgn] |= CGF_DIRTY;
}
/*
* Flush cgs to disk, recomputing anything they're marked as needing.
*/
static void
flush_cgs(void)
{
int i;
for (i = 0; i < newsb->fs_ncg; i++) {
if (cgflags[i] & CGF_BLKMAPS) {
rescan_blkmaps(i);
}
if (cgflags[i] & CGF_INOMAPS) {
rescan_inomaps(i);
}
if (cgflags[i] & CGF_DIRTY) {
cgs[i]->cg_rotor = 0;
cgs[i]->cg_frotor = 0;
cgs[i]->cg_irotor = 0;
writeat(fsbtodb(newsb, cgtod(newsb, i)), cgs[i],
cgblksz);
}
}
writeat(fsbtodb(newsb, newsb->fs_csaddr), csums, newsb->fs_cssize);
}
/*
* Write the superblock, both to the main superblock and to each cg's
* alternative superblock.
*/
static void
write_sbs(void)
{
int i;
writeat(SBLOCK, newsb, SBSIZE);
for (i = 0; i < newsb->fs_ncg; i++) {
writeat(fsbtodb(newsb, cgsblock(newsb, i)), newsb, SBSIZE);
}
}
/*
* main().
*/
int main(int, char **);
int
main(int ac, char **av)
{
if (ac != 3) {
fprintf(stderr, "Usage: %s filesystem new-size\n", __progname);
exit(1);
}
fd = open(av[1], O_RDWR, 0);
if (fd < 0) {
fprintf(stderr, "%s: %s: %s\n", __progname, av[1],
strerror(errno));
exit(1);
}
checksmallio();
newsize = atoi(av[2]);
oldsb = (struct fs *) & sbbuf;
newsb = (struct fs *) (SBSIZE + (char *) &sbbuf);
readat(SBLOCK, oldsb, SBSIZE);
if (oldsb->fs_magic != FS_MAGIC) {
fprintf(stderr, "%s: %s: bad magic number\n", __progname,
av[1]);
exit(1);
}
oldsb->fs_qbmask = ~(int64_t) oldsb->fs_bmask;
oldsb->fs_qfmask = ~(int64_t) oldsb->fs_fmask;
if (oldsb->fs_ipg % INOPB(oldsb)) {
printf("ipg[%d] %% INOPB[%d] != 0\n", (int) oldsb->fs_ipg,
(int) INOPB(oldsb));
exit(1);
}
/* The superblock is bigger than struct fs (there are trailing tables,
* of non-fixed size); make sure we copy the whole thing. SBSIZE may
* be an over-estimate, but we do this just once, so being generous is
* cheap. */
bcopy(oldsb, newsb, SBSIZE);
loadcgs();
if (newsize > fsbtodb(oldsb, oldsb->fs_size)) {
grow();
} else if (newsize < fsbtodb(oldsb, oldsb->fs_size)) {
shrink();
}
flush_cgs();
write_sbs();
exit(0);
}