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NetBSD/sys/fs/efs/efs_subr.c

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/* $NetBSD: efs_subr.c,v 1.14 2021/12/10 20:36:04 andvar Exp $ */
/*
* Copyright (c) 2006 Stephen M. Rumble <rumble@ephemeral.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: efs_subr.c,v 1.14 2021/12/10 20:36:04 andvar Exp $");
#include <sys/param.h>
#include <sys/kauth.h>
#include <sys/lwp.h>
#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/namei.h>
#include <sys/stat.h>
#include <sys/malloc.h>
#include <miscfs/genfs/genfs_node.h>
#include <fs/efs/efs.h>
#include <fs/efs/efs_sb.h>
#include <fs/efs/efs_dir.h>
#include <fs/efs/efs_genfs.h>
#include <fs/efs/efs_mount.h>
#include <fs/efs/efs_extent.h>
#include <fs/efs/efs_dinode.h>
#include <fs/efs/efs_inode.h>
#include <fs/efs/efs_subr.h>
struct pool efs_inode_pool;
/*
* Calculate a checksum for the provided superblock in __host byte order__.
*
* At some point SGI changed the checksum algorithm slightly, which can be
* enabled with the 'new' flag.
*
* Presumably this change occurred on or before 24 Oct 1988 (around IRIX 3.1),
* so we're pretty unlikely to ever actually see an old checksum. Further, it
* means that EFS_NEWMAGIC filesystems (IRIX >= 3.3) must match the new
* checksum whereas EFS_MAGIC filesystems could potentially use either
* algorithm.
*
* See comp.sys.sgi <1991Aug9.050838.16876@odin.corp.sgi.com>
*/
int32_t
efs_sb_checksum(struct efs_sb *esb, int new)
{
int i;
int32_t cksum;
uint8_t *sbarray = (uint8_t *)esb;
KASSERT((EFS_SB_CHECKSUM_SIZE % 2) == 0);
for (i = cksum = 0; i < EFS_SB_CHECKSUM_SIZE; i += 2) {
uint16_t v;
memcpy(&v, &sbarray[i], sizeof(v));
cksum ^= be16toh(v);
cksum = (cksum << 1) | (new && cksum < 0);
}
return (cksum);
}
/*
* Determine if the superblock is valid.
*
* Returns 0 if valid, else invalid. If invalid, 'why' is set to an
* explanation.
*/
int
efs_sb_validate(struct efs_sb *esb, const char **why)
{
uint32_t ocksum, ncksum;
*why = NULL;
if (be32toh(esb->sb_magic) != EFS_SB_MAGIC &&
be32toh(esb->sb_magic) != EFS_SB_NEWMAGIC) {
*why = "sb_magic invalid";
return (1);
}
ocksum = htobe32(efs_sb_checksum(esb, 0));
ncksum = htobe32(efs_sb_checksum(esb, 1));
if (esb->sb_checksum != ocksum && esb->sb_checksum != ncksum) {
*why = "sb_checksum invalid";
return (1);
}
if (be32toh(esb->sb_size) > EFS_SIZE_MAX) {
*why = "sb_size > EFS_SIZE_MAX";
return (1);
}
if (be32toh(esb->sb_firstcg) <= EFS_BB_BITMAP) {
*why = "sb_firstcg <= EFS_BB_BITMAP";
return (1);
}
/* XXX - add better sb consistency checks here */
if (esb->sb_cgfsize == 0 ||
esb->sb_cgisize == 0 ||
esb->sb_ncg == 0 ||
esb->sb_bmsize == 0) {
*why = "something bad happened";
return (1);
}
return (0);
}
/*
* Determine the basic block offset and inode index within that block, given
* the inode 'ino' and filesystem parameters _in host byte order_. The inode
* will live at byte address 'bboff' * EFS_BB_SIZE + 'index' * EFS_DINODE_SIZE.
*/
void
efs_locate_inode(ino_t ino, struct efs_sb *sbp, uint32_t *bboff, int *index)
{
uint32_t cgfsize, firstcg;
uint16_t cgisize;
cgisize = be16toh(sbp->sb_cgisize);
cgfsize = be32toh(sbp->sb_cgfsize);
firstcg = be32toh(sbp->sb_firstcg);
*bboff = firstcg + ((ino / (cgisize * EFS_DINODES_PER_BB)) * cgfsize) +
((ino % (cgisize * EFS_DINODES_PER_BB)) / EFS_DINODES_PER_BB);
*index = ino & (EFS_DINODES_PER_BB - 1);
}
/*
* Read in an inode from disk.
*
* We actually take in four inodes at a time. Hopefully these will stick
* around in the buffer cache and get used without going to disk.
*
* Returns 0 on success.
*/
int
efs_read_inode(struct efs_mount *emp, ino_t ino, struct lwp *l,
struct efs_dinode *di)
{
struct efs_sb *sbp;
struct buf *bp;
int index, err;
uint32_t bboff;
sbp = &emp->em_sb;
efs_locate_inode(ino, sbp, &bboff, &index);
err = efs_bread(emp, bboff, l, &bp);
if (err) {
return (err);
}
memcpy(di, ((struct efs_dinode *)bp->b_data) + index, sizeof(*di));
brelse(bp, 0);
return (0);
}
/*
* Perform a read from our device handling the potential DEV_BSIZE
* messiness (although as of 19.2.2006, all ports appear to use 512) as
* we as EFS block sizing.
*
* bboff: basic block offset
*
* Returns 0 on success.
*/
int
efs_bread(struct efs_mount *emp, uint32_t bboff, struct lwp *l, struct buf **bp)
{
KASSERT(bboff < EFS_SIZE_MAX);
return (bread(emp->em_devvp, (daddr_t)bboff * (EFS_BB_SIZE / DEV_BSIZE),
EFS_BB_SIZE, 0, bp));
}
/*
* Synchronise the in-core, host ordered and typed inode fields with their
* corresponding on-disk, EFS ordered and typed copies.
*
* This is the inverse of efs_dinode_sync_inode(), and should be called when
* an inode is loaded from disk.
*/
void
efs_sync_dinode_to_inode(struct efs_inode *ei)
{
ei->ei_mode = be16toh(ei->ei_di.di_mode); /*same as nbsd*/
ei->ei_nlink = be16toh(ei->ei_di.di_nlink);
ei->ei_uid = be16toh(ei->ei_di.di_uid);
ei->ei_gid = be16toh(ei->ei_di.di_gid);
ei->ei_size = be32toh(ei->ei_di.di_size);
ei->ei_atime = be32toh(ei->ei_di.di_atime);
ei->ei_mtime = be32toh(ei->ei_di.di_mtime);
ei->ei_ctime = be32toh(ei->ei_di.di_ctime);
ei->ei_gen = be32toh(ei->ei_di.di_gen);
ei->ei_numextents = be16toh(ei->ei_di.di_numextents);
ei->ei_version = ei->ei_di.di_version;
}
/*
* Synchronise the on-disk, EFS ordered and typed inode fields with their
* corresponding in-core, host ordered and typed copies.
*
* This is the inverse of efs_inode_sync_dinode(), and should be called before
* an inode is flushed to disk.
*/
void
efs_sync_inode_to_dinode(struct efs_inode *ei)
{
panic("readonly -- no need to call me");
}
#ifdef DIAGNOSTIC
/*
* Ensure that the in-core inode's host cached fields match its on-disk copy.
*
* Returns 0 if they match.
*/
static int
efs_is_inode_synced(struct efs_inode *ei)
{
int s;
s = 0;
/* XXX -- see above remarks about assumption */
s += (ei->ei_mode != be16toh(ei->ei_di.di_mode));
s += (ei->ei_nlink != be16toh(ei->ei_di.di_nlink));
s += (ei->ei_uid != be16toh(ei->ei_di.di_uid));
s += (ei->ei_gid != be16toh(ei->ei_di.di_gid));
s += (ei->ei_size != be32toh(ei->ei_di.di_size));
s += (ei->ei_atime != be32toh(ei->ei_di.di_atime));
s += (ei->ei_mtime != be32toh(ei->ei_di.di_mtime));
s += (ei->ei_ctime != be32toh(ei->ei_di.di_ctime));
s += (ei->ei_gen != be32toh(ei->ei_di.di_gen));
s += (ei->ei_numextents != be16toh(ei->ei_di.di_numextents));
s += (ei->ei_version != ei->ei_di.di_version);
return (s);
}
#endif
/*
* Given an efs_dirblk structure and a componentname to search for, return the
* corresponding inode if it is found.
*
* Returns 0 on success.
*/
static int
efs_dirblk_lookup(struct efs_dirblk *dir, struct componentname *cn,
ino_t *inode)
{
struct efs_dirent *de;
int i, slot __diagused, offset;
KASSERT(cn->cn_namelen <= EFS_DIRENT_NAMELEN_MAX);
slot = offset = 0;
for (i = 0; i < dir->db_slots; i++) {
offset = EFS_DIRENT_OFF_EXPND(dir->db_space[i]);
if (offset == EFS_DIRBLK_SLOT_FREE)
continue;
de = (struct efs_dirent *)((char *)dir + offset);
if (de->de_namelen == cn->cn_namelen &&
(strncmp(cn->cn_nameptr, de->de_name, cn->cn_namelen) == 0)){
slot = i;
break;
}
}
if (i == dir->db_slots)
return (ENOENT);
KASSERT(slot < offset && offset < EFS_DIRBLK_SPACE_SIZE);
de = (struct efs_dirent *)((char *)dir + offset);
*inode = be32toh(de->de_inumber);
return (0);
}
/*
* Given an extent descriptor that represents a directory, look up
* componentname within its efs_dirblk's. If it is found, return the
* corresponding inode in 'ino'.
*
* Returns 0 on success.
*/
static int
efs_extent_lookup(struct efs_mount *emp, struct efs_extent *ex,
struct componentname *cn, ino_t *ino)
{
struct efs_dirblk *db;
struct buf *bp;
int i, err;
/*
* Read in each of the dirblks until we find our entry.
* If we don't, return ENOENT.
*/
for (i = 0; i < ex->ex_length; i++) {
err = efs_bread(emp, ex->ex_bn + i, NULL, &bp);
if (err) {
printf("efs: warning: invalid extent descriptor\n");
return (err);
}
db = (struct efs_dirblk *)bp->b_data;
if (efs_dirblk_lookup(db, cn, ino) == 0) {
brelse(bp, 0);
return (0);
}
brelse(bp, 0);
}
return (ENOENT);
}
/*
* Given the provided in-core inode, look up the pathname requested. If
* we find it, 'ino' reflects its corresponding on-disk inode number.
*
* Returns 0 on success.
*/
int
efs_inode_lookup(struct efs_mount *emp, struct efs_inode *ei,
struct componentname *cn, ino_t *ino)
{
struct efs_extent ex;
struct efs_extent_iterator exi;
int ret;
KASSERT(VOP_ISLOCKED(ei->ei_vp));
#ifdef DIAGNOSTIC
KASSERT(efs_is_inode_synced(ei) == 0);
#endif
KASSERT((ei->ei_mode & S_IFMT) == S_IFDIR);
efs_extent_iterator_init(&exi, ei, 0);
while ((ret = efs_extent_iterator_next(&exi, &ex)) == 0) {
if (efs_extent_lookup(emp, &ex, cn, ino) == 0) {
return (0);
}
}
return ((ret == -1) ? ENOENT : ret);
}
/*
* Convert on-disk extent structure to in-core format.
*/
void
efs_dextent_to_extent(struct efs_dextent *dex, struct efs_extent *ex)
{
KASSERT(dex != NULL && ex != NULL);
ex->ex_magic = dex->ex_bytes[0];
ex->ex_bn = be32toh(dex->ex_words[0]) & 0x00ffffff;
ex->ex_length = dex->ex_bytes[4];
ex->ex_offset = be32toh(dex->ex_words[1]) & 0x00ffffff;
}
/*
* Convert in-core extent format to on-disk structure.
*/
void
efs_extent_to_dextent(struct efs_extent *ex, struct efs_dextent *dex)
{
KASSERT(ex != NULL && dex != NULL);
KASSERT(ex->ex_magic == EFS_EXTENT_MAGIC);
KASSERT((ex->ex_bn & ~EFS_EXTENT_BN_MASK) == 0);
KASSERT((ex->ex_offset & ~EFS_EXTENT_OFFSET_MASK) == 0);
dex->ex_words[0] = htobe32(ex->ex_bn);
dex->ex_bytes[0] = ex->ex_magic;
dex->ex_words[1] = htobe32(ex->ex_offset);
dex->ex_bytes[4] = ex->ex_length;
}
/*
* Initialise an extent iterator.
*
* If start_hint is non-0, attempt to set up the iterator beginning with the
* extent descriptor in which the start_hint'th byte exists. Callers must not
* expect success (this is simply an optimisation), so we reserve the right
* to start from the beginning.
*/
void
efs_extent_iterator_init(struct efs_extent_iterator *exi, struct efs_inode *eip,
off_t start_hint)
{
struct efs_extent ex, ex2;
struct buf *bp;
struct efs_mount *emp = VFSTOEFS(eip->ei_vp->v_mount);
off_t offset, length, next;
int i, err, numextents, numinextents;
int hi, lo, mid;
int indir;
exi->exi_eip = eip;
exi->exi_next = 0;
exi->exi_dnext = 0;
exi->exi_innext = 0;
if (start_hint == 0)
return;
/* force iterator to end if hint is too big */
if (start_hint >= eip->ei_size) {
exi->exi_next = eip->ei_numextents;
return;
}
/*
* Use start_hint to jump to the right extent descriptor. We'll
* iterate over the 12 indirect extents because it's cheap, then
* bring the appropriate vector into core and binary search it.
*/
/*
* Handle the small file case separately first...
*/
if (eip->ei_numextents <= EFS_DIRECTEXTENTS) {
for (i = 0; i < eip->ei_numextents; i++) {
efs_dextent_to_extent(&eip->ei_di.di_extents[i], &ex);
offset = ex.ex_offset * EFS_BB_SIZE;
length = ex.ex_length * EFS_BB_SIZE;
if (start_hint >= offset &&
start_hint < (offset + length)) {
exi->exi_next = exi->exi_dnext = i;
return;
}
}
/* shouldn't get here, no? */
EFS_DPRINTF(("efs_extent_iterator_init: bad direct extents\n"));
return;
}
/*
* Now do the large files with indirect extents...
*
* The first indirect extent's ex_offset field contains the
* number of indirect extents used.
*/
efs_dextent_to_extent(&eip->ei_di.di_extents[0], &ex);
numinextents = ex.ex_offset;
if (numinextents < 1 || numinextents >= EFS_DIRECTEXTENTS) {
EFS_DPRINTF(("efs_extent_iterator_init: bad ex.ex_offset\n"));
return;
}
next = 0;
indir = -1;
numextents = 0;
for (i = 0; i < numinextents; i++) {
efs_dextent_to_extent(&eip->ei_di.di_extents[i], &ex);
err = efs_bread(emp, ex.ex_bn, NULL, &bp);
if (err) {
return;
}
efs_dextent_to_extent((struct efs_dextent *)bp->b_data, &ex2);
brelse(bp, 0);
offset = ex2.ex_offset * EFS_BB_SIZE;
if (offset > start_hint) {
indir = MAX(0, i - 1);
break;
}
/* number of extents prior to this indirect vector of extents */
next += numextents;
/* number of extents within this indirect vector of extents */
numextents = ex.ex_length * EFS_EXTENTS_PER_BB;
numextents = MIN(numextents, eip->ei_numextents - next);
}
/*
* We hit the end, so assume it's in the last extent.
*/
if (indir == -1)
indir = numinextents - 1;
/*
* Binary search to find our desired direct extent.
*/
lo = 0;
mid = 0;
hi = numextents - 1;
efs_dextent_to_extent(&eip->ei_di.di_extents[indir], &ex);
while (lo <= hi) {
int bboff;
int index;
mid = (lo + hi) / 2;
bboff = mid / EFS_EXTENTS_PER_BB;
index = mid % EFS_EXTENTS_PER_BB;
err = efs_bread(emp, ex.ex_bn + bboff, NULL, &bp);
if (err) {
EFS_DPRINTF(("efs_extent_iterator_init: bsrch read\n"));
return;
}
efs_dextent_to_extent((struct efs_dextent *)bp->b_data + index,
&ex2);
brelse(bp, 0);
offset = ex2.ex_offset * EFS_BB_SIZE;
length = ex2.ex_length * EFS_BB_SIZE;
if (start_hint >= offset && start_hint < (offset + length))
break;
if (start_hint < offset)
hi = mid - 1;
else
lo = mid + 1;
}
/*
* This is bad. Either the hint is bogus (which shouldn't
* happen) or the extent list must be screwed up. We
* have to abort.
*/
if (lo > hi) {
EFS_DPRINTF(("efs_extent_iterator_init: bsearch "
"failed to find extent\n"));
return;
}
exi->exi_next = next + mid;
exi->exi_dnext = indir;
exi->exi_innext = mid;
}
/*
* Return the next EFS extent.
*
* Returns 0 if another extent was iterated, -1 if we've exhausted all
* extents, or an error number. If 'exi' is non-NULL, the next extent is
* written to it (should it exist).
*/
int
efs_extent_iterator_next(struct efs_extent_iterator *exi,
struct efs_extent *exp)
{
struct efs_extent ex;
struct efs_dextent *dexp;
struct efs_inode *eip = exi->exi_eip;
struct buf *bp;
int err, bboff, index;
if (exi->exi_next++ >= eip->ei_numextents)
return (-1);
/* direct or indirect extents? */
if (eip->ei_numextents <= EFS_DIRECTEXTENTS) {
if (exp != NULL) {
dexp = &eip->ei_di.di_extents[exi->exi_dnext++];
efs_dextent_to_extent(dexp, exp);
}
} else {
efs_dextent_to_extent(
&eip->ei_di.di_extents[exi->exi_dnext], &ex);
bboff = exi->exi_innext / EFS_EXTENTS_PER_BB;
index = exi->exi_innext % EFS_EXTENTS_PER_BB;
err = efs_bread(VFSTOEFS(eip->ei_vp->v_mount),
ex.ex_bn + bboff, NULL, &bp);
if (err) {
EFS_DPRINTF(("efs_extent_iterator_next: "
"efs_bread failed: %d\n", err));
return (err);
}
if (exp != NULL) {
dexp = (struct efs_dextent *)bp->b_data + index;
efs_dextent_to_extent(dexp, exp);
}
brelse(bp, 0);
bboff = exi->exi_innext++ / EFS_EXTENTS_PER_BB;
if (bboff >= ex.ex_length) {
exi->exi_innext = 0;
exi->exi_dnext++;
}
}
return (0);
}
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