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The ffs superblock includes a 128-byte region for use by temporary

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in-core pointers to summary information. An array in this region
(fs_csp) could overflow on filesystems with a very large number of
cylinder groups (~16000 on i386 with 8k blocks). When this happens,
other fields in the superblock get corrupted, and fsck refuses to
check the filesystem.

Solve this problem by replacing the fs_csp array in 'struct fs'
with a single pointer, and add padding to keep the length of the
128-byte region fixed. Update the kernel and userland utilities
to use just this single pointer.

With this change, the kernel no longer makes use of the superblock
fields 'fs_csshift' and 'fs_csmask'. Add a comment to newfs/mkfs.c
to indicate that these fields must be calculated for compatibility
with older kernels.

Reviewed by:	mckusick
This commit is contained in:
Ian Dowse 2001-01-15 18:30:40 +00:00
parent 8fbaa337ac
commit f55ff3f3ef
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=71073
9 changed files with 53 additions and 44 deletions
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4
sbin/dumpfs/dumpfs.c
View File

@ -205,15 +205,15 @@ dumpfs(name)
}
}
printf("\ncs[].cs_(nbfree,ndir,nifree,nffree):\n\t");
afs.fs_csp = calloc(1, afs.fs_cssize);
for (i = 0, j = 0; i < afs.fs_cssize; i += afs.fs_bsize, j++) {
size = afs.fs_cssize - i < afs.fs_bsize ?
afs.fs_cssize - i : afs.fs_bsize;
afs.fs_csp[j] = calloc(1, size);
if (lseek(fd,
(off_t)(fsbtodb(&afs, (afs.fs_csaddr + j * afs.fs_frag))) *
(off_t)dev_bsize, SEEK_SET) == (off_t)-1)
goto err;
if (read(fd, afs.fs_csp[j], size) != size)
if (read(fd, (char *)afs.fs_csp + i, size) != size)
goto err;
}
for (i = 0; i < afs.fs_ncg; i++) {

2
sbin/fsck_ffs/fsutil.c
View File

@ -249,7 +249,7 @@ flush(fd, bp)
if (bp != &sblk)
return;
for (i = 0, j = 0; i < sblock.fs_cssize; i += sblock.fs_bsize, j++) {
bwrite(fswritefd, (char *)sblock.fs_csp[j],
bwrite(fswritefd, (char *)sblock.fs_csp + i,
fsbtodb(&sblock, sblock.fs_csaddr + j * sblock.fs_frag),
sblock.fs_cssize - i < sblock.fs_bsize ?
sblock.fs_cssize - i : sblock.fs_bsize);

7
sbin/fsck_ffs/setup.c
View File

@ -258,11 +258,11 @@ setup(dev)
* read in the summary info.
*/
asked = 0;
sblock.fs_csp = calloc(1, sblock.fs_cssize);
for (i = 0, j = 0; i < sblock.fs_cssize; i += sblock.fs_bsize, j++) {
size = sblock.fs_cssize - i < sblock.fs_bsize ?
sblock.fs_cssize - i : sblock.fs_bsize;
sblock.fs_csp[j] = (struct csum *)calloc(1, (unsigned)size);
if (bread(fsreadfd, (char *)sblock.fs_csp[j],
if (bread(fsreadfd, (char *)sblock.fs_csp + i,
fsbtodb(&sblock, sblock.fs_csaddr + j * sblock.fs_frag),
size) != 0 && !asked) {
pfatal("BAD SUMMARY INFORMATION");
@ -380,7 +380,8 @@ readsb(listerr)
altsblock.fs_optim = sblock.fs_optim;
altsblock.fs_rotdelay = sblock.fs_rotdelay;
altsblock.fs_maxbpg = sblock.fs_maxbpg;
memmove(altsblock.fs_csp, sblock.fs_csp, sizeof sblock.fs_csp);
memmove(altsblock.fs_ocsp, sblock.fs_ocsp, sizeof sblock.fs_ocsp);
altsblock.fs_csp = sblock.fs_csp;
altsblock.fs_maxcluster = sblock.fs_maxcluster;
memmove(altsblock.fs_fsmnt, sblock.fs_fsmnt, sizeof sblock.fs_fsmnt);
memmove(altsblock.fs_snapinum, sblock.fs_snapinum,

2
sbin/fsck_ifs/fsutil.c
View File

@ -249,7 +249,7 @@ flush(fd, bp)
if (bp != &sblk)
return;
for (i = 0, j = 0; i < sblock.fs_cssize; i += sblock.fs_bsize, j++) {
bwrite(fswritefd, (char *)sblock.fs_csp[j],
bwrite(fswritefd, (char *)sblock.fs_csp + i,
fsbtodb(&sblock, sblock.fs_csaddr + j * sblock.fs_frag),
sblock.fs_cssize - i < sblock.fs_bsize ?
sblock.fs_cssize - i : sblock.fs_bsize);

7
sbin/fsck_ifs/setup.c
View File

@ -258,11 +258,11 @@ setup(dev)
* read in the summary info.
*/
asked = 0;
sblock.fs_csp = calloc(1, sblock.fs_cssize);
for (i = 0, j = 0; i < sblock.fs_cssize; i += sblock.fs_bsize, j++) {
size = sblock.fs_cssize - i < sblock.fs_bsize ?
sblock.fs_cssize - i : sblock.fs_bsize;
sblock.fs_csp[j] = (struct csum *)calloc(1, (unsigned)size);
if (bread(fsreadfd, (char *)sblock.fs_csp[j],
if (bread(fsreadfd, (char *)sblock.fs_csp + i,
fsbtodb(&sblock, sblock.fs_csaddr + j * sblock.fs_frag),
size) != 0 && !asked) {
pfatal("BAD SUMMARY INFORMATION");
@ -382,7 +382,8 @@ readsb(listerr)
altsblock.fs_optim = sblock.fs_optim;
altsblock.fs_rotdelay = sblock.fs_rotdelay;
altsblock.fs_maxbpg = sblock.fs_maxbpg;
memmove(altsblock.fs_csp, sblock.fs_csp, sizeof sblock.fs_csp);
memmove(altsblock.fs_ocsp, sblock.fs_ocsp, sizeof sblock.fs_ocsp);
altsblock.fs_csp = sblock.fs_csp;
altsblock.fs_maxcluster = sblock.fs_maxcluster;
memmove(altsblock.fs_fsmnt, sblock.fs_fsmnt, sizeof sblock.fs_fsmnt);
memmove(altsblock.fs_snapinum, sblock.fs_snapinum,

5
sbin/newfs/mkfs.c
View File

@ -633,6 +633,11 @@ mkfs(pp, fsys, fi, fo)
sblock.fs_csaddr = cgdmin(&sblock, 0);
sblock.fs_cssize =
fragroundup(&sblock, sblock.fs_ncg * sizeof(struct csum));
/*
* The superblock fields 'fs_csmask' and 'fs_csshift' are no
* longer used. However, we still initialise them so that the
* filesystem remains compatible with old kernels.
*/
i = sblock.fs_bsize / sizeof(struct csum);
sblock.fs_csmask = ~(i - 1);
for (sblock.fs_csshift = 0; i > 1; i >>= 1)

5
sys/ufs/ffs/ffs_snapshot.c
View File

@ -83,6 +83,7 @@ ffs_snapshot(mp, snapfile)
int error, cg, snaploc, indiroff, numblks;
int i, size, base, len, loc, inoblkcnt;
int blksperindir, flag = mp->mnt_flag;
void *space;
struct fs *copy_fs, *fs = VFSTOUFS(mp)->um_fs;
struct proc *p = CURPROC;
struct inode *devip, *ip, *xp;
@ -346,6 +347,7 @@ ffs_snapshot(mp, snapfile)
blkno = fragstoblks(fs, fs->fs_csaddr);
len = howmany(fs->fs_cssize, fs->fs_bsize) - 1;
size = fs->fs_bsize;
space = fs->fs_csp;
for (loc = 0; loc <= len; loc++) {
error = VOP_BALLOC(vp, lblktosize(fs, (off_t)(blkno + loc)),
fs->fs_bsize, KERNCRED, 0, &nbp);
@ -355,7 +357,8 @@ ffs_snapshot(mp, snapfile)
readblock(nbp, blkno + loc);
size = fs->fs_cssize - loc * fs->fs_bsize;
}
bcopy(fs->fs_csp[loc], nbp->b_data, size);
bcopy(space, nbp->b_data, size);
space = (char *)space + size;
nbp->b_flags |= B_VALIDSUSPWRT;
bawrite(nbp);
}

31
sys/ufs/ffs/ffs_vfsops.c
View File

@ -365,7 +365,7 @@ ffs_reload(mp, cred, p)
{
register struct vnode *vp, *nvp, *devvp;
struct inode *ip;
struct csum *space;
void *space;
struct buf *bp;
struct fs *fs, *newfs;
struct partinfo dpart;
@ -419,7 +419,7 @@ ffs_reload(mp, cred, p)
* new superblock. These should really be in the ufsmount. XXX
* Note that important parameters (eg fs_ncg) are unchanged.
*/
bcopy(&fs->fs_csp[0], &newfs->fs_csp[0], sizeof(fs->fs_csp));
newfs->fs_csp = fs->fs_csp;
newfs->fs_maxcluster = fs->fs_maxcluster;
bcopy(newfs, fs, (u_int)fs->fs_sbsize);
if (fs->fs_sbsize < SBSIZE)
@ -432,7 +432,7 @@ ffs_reload(mp, cred, p)
* Step 3: re-read summary information from disk.
*/
blks = howmany(fs->fs_cssize, fs->fs_fsize);
space = fs->fs_csp[0];
space = fs->fs_csp;
for (i = 0; i < blks; i += fs->fs_frag) {
size = fs->fs_bsize;
if (i + fs->fs_frag > blks)
@ -441,7 +441,8 @@ ffs_reload(mp, cred, p)
NOCRED, &bp);
if (error)
return (error);
bcopy(bp->b_data, fs->fs_csp[fragstoblks(fs, i)], (u_int)size);
bcopy(bp->b_data, space, (u_int)size);
space = (char *)space + size;
brelse(bp);
}
/*
@ -513,7 +514,7 @@ ffs_mountfs(devvp, mp, p, malloctype)
register struct fs *fs;
dev_t dev;
struct partinfo dpart;
caddr_t base, space;
void *space;
int error, i, blks, size, ronly;
int32_t *lp;
struct ucred *cred;
@ -623,24 +624,24 @@ ffs_mountfs(devvp, mp, p, malloctype)
blks = howmany(size, fs->fs_fsize);
if (fs->fs_contigsumsize > 0)
size += fs->fs_ncg * sizeof(int32_t);
base = space = malloc((u_long)size, M_UFSMNT, M_WAITOK);
space = malloc((u_long)size, M_UFSMNT, M_WAITOK);
fs->fs_csp = space;
for (i = 0; i < blks; i += fs->fs_frag) {
size = fs->fs_bsize;
if (i + fs->fs_frag > blks)
size = (blks - i) * fs->fs_fsize;
if ((error = bread(devvp, fsbtodb(fs, fs->fs_csaddr + i), size,
cred, &bp)) != 0) {
free(base, M_UFSMNT);
free(fs->fs_csp, M_UFSMNT);
goto out;
}
bcopy(bp->b_data, space, (u_int)size);
fs->fs_csp[fragstoblks(fs, i)] = (struct csum *)space;
space += size;
space = (char *)space + size;
brelse(bp);
bp = NULL;
}
if (fs->fs_contigsumsize > 0) {
fs->fs_maxcluster = lp = (int32_t *)space;
fs->fs_maxcluster = lp = space;
for (i = 0; i < fs->fs_ncg; i++)
*lp++ = fs->fs_contigsumsize;
}
@ -691,7 +692,7 @@ ffs_mountfs(devvp, mp, p, malloctype)
if (ronly == 0) {
if ((fs->fs_flags & FS_DOSOFTDEP) &&
(error = softdep_mount(devvp, mp, fs, cred)) != 0) {
free(base, M_UFSMNT);
free(fs->fs_csp, M_UFSMNT);
goto out;
}
if (fs->fs_snapinum[0] != 0)
@ -808,7 +809,7 @@ ffs_unmount(mp, mntflags, p)
vrele(ump->um_devvp);
free(fs->fs_csp[0], M_UFSMNT);
free(fs->fs_csp, M_UFSMNT);
free(fs, M_UFSMNT);
free(ump, M_UFSMNT);
mp->mnt_data = (qaddr_t)0;
@ -1263,14 +1264,14 @@ ffs_sbupdate(mp, waitfor)
register struct fs *dfs, *fs = mp->um_fs;
register struct buf *bp;
int blks;
caddr_t space;
void *space;
int i, size, error, allerror = 0;
/*
* First write back the summary information.
*/
blks = howmany(fs->fs_cssize, fs->fs_fsize);
space = (caddr_t)fs->fs_csp[0];
space = fs->fs_csp;
for (i = 0; i < blks; i += fs->fs_frag) {
size = fs->fs_bsize;
if (i + fs->fs_frag > blks)
@ -1278,7 +1279,7 @@ ffs_sbupdate(mp, waitfor)
bp = getblk(mp->um_devvp, fsbtodb(fs, fs->fs_csaddr + i),
size, 0, 0);
bcopy(space, bp->b_data, (u_int)size);
space += size;
space = (char *)space + size;
if (waitfor != MNT_WAIT)
bawrite(bp);
else if ((error = bwrite(bp)) != 0)

34
sys/ufs/ffs/fs.h
View File

@ -106,14 +106,17 @@
#define MAXMNTLEN 512
/*
* The limit on the amount of summary information per file system
* is defined by MAXCSBUFS. It is currently parameterized for a
* size of 128 bytes (2 million cylinder groups on machines with
* 32-bit pointers, and 1 million on 64-bit machines). One pointer
* is taken away to point to an array of cluster sizes that is
* computed as cylinder groups are inspected.
* There is a 128-byte region in the superblock reserved for in-core
* pointers to summary information. Originally this included an array
* of pointers to blocks of struct csum; now there are just two
* pointers and the remaining space is padded with fs_ocsp[].
*
* NOCSPTRS determines the size of this padding. One pointer (fs_csp)
* is taken away to point to a contiguous array of struct csum for
* all cylinder groups; a second (fs_maxcluster) points to an array
* of cluster sizes that is computed as cylinder groups are inspected.
*/
#define MAXCSBUFS ((128 / sizeof(void *)) - 1)
#define NOCSPTRS ((128 / sizeof(void *)) - 2)
/*
* A summary of contiguous blocks of various sizes is maintained
@ -167,9 +170,6 @@
* from first cylinder group data blocks. These blocks have to be
* read in from fs_csaddr (size fs_cssize) in addition to the
* super block.
*
* N.B. sizeof(struct csum) must be a power of two in order for
* the ``fs_cs'' macro to work (see below).
*/
struct csum {
int32_t cs_ndir; /* number of directories */
@ -213,8 +213,8 @@ struct fs {
int32_t fs_fragshift; /* block to frag shift */
int32_t fs_fsbtodb; /* fsbtodb and dbtofsb shift constant */
int32_t fs_sbsize; /* actual size of super block */
int32_t fs_csmask; /* csum block offset */
int32_t fs_csshift; /* csum block number */
int32_t fs_csmask; /* csum block offset (now unused) */
int32_t fs_csshift; /* csum block number (now unused) */
int32_t fs_nindir; /* value of NINDIR */
int32_t fs_inopb; /* value of INOPB */
int32_t fs_nspf; /* value of NSPF */
@ -250,8 +250,9 @@ struct fs {
u_char fs_fsmnt[MAXMNTLEN]; /* name mounted on */
/* these fields retain the current block allocation info */
int32_t fs_cgrotor; /* last cg searched */
struct csum *fs_csp[MAXCSBUFS];/* list of fs_cs info buffers */
int32_t *fs_maxcluster; /* max cluster in each cyl group */
void *fs_ocsp[NOCSPTRS]; /* padding; was list of fs_cs buffers */
struct csum *fs_csp; /* cg summary info buffer for fs_cs */
int32_t *fs_maxcluster; /* max cluster in each cyl group */
int32_t fs_cpc; /* cyl per cycle in postbl */
int16_t fs_opostbl[16][8]; /* old rotation block list head */
int32_t fs_snapinum[FSMAXSNAP];/* list of snapshot inode numbers */
@ -328,11 +329,8 @@ struct fs {
/*
* Convert cylinder group to base address of its global summary info.
*
* N.B. This macro assumes that sizeof(struct csum) is a power of two.
*/
#define fs_cs(fs, indx) \
fs_csp[(indx) >> (fs)->fs_csshift][(indx) & ~(fs)->fs_csmask]
#define fs_cs(fs, indx) fs_csp[indx]
/*
* Cylinder group block for a file system.