/*
* Remove a directory entry after a call to namei, using
* the auxiliary results it provided. The entry
* ulr_offset contains the offset into the directory of the
* entry to be eliminated. The ulr_count field contains the
* size of the previous record in the directory. If this
* is 0, the first entry is being deleted, so we need only
* zero the inode number to mark the entry as free. If the
* entry is not the first in the directory, we must reclaim
* the space of the now empty record by adding the record size
* to the size of the previous entry.
*/
int
ext2fs_dirremove(struct vnode *dvp, const struct ufs_lookup_results *ulr,
struct componentname *cnp)
{
struct inode *dp;
struct ext2fs_direct *ep;
struct buf *bp;
int error;
dp = VTOI(dvp);
if (ulr->ulr_count == 0) {
/*
* First entry in block: set d_ino to zero.
*/
error = ext2fs_blkatoff(dvp, (off_t)ulr->ulr_offset,
(void *)&ep, &bp);
if (error != 0)
return (error);
ep->e2d_ino = 0;
error = VOP_BWRITE(bp->b_vp, bp);
dp->i_flag |= IN_CHANGE | IN_UPDATE;
return (error);
}
/*
* Collapse new free space into previous entry.
*/
error = ext2fs_blkatoff(dvp, (off_t)(ulr->ulr_offset - ulr->ulr_count),
(void *)&ep, &bp);
if (error != 0)
return (error);
ep->e2d_reclen = h2fs16(fs2h16(ep->e2d_reclen) + ulr->ulr_reclen);
error = VOP_BWRITE(bp->b_vp, bp);
dp->i_flag |= IN_CHANGE | IN_UPDATE;
return (error);
}
/*
* Rewrite an existing directory entry to point at the inode
* supplied. The parameters describing the directory entry are
* set up by a call to namei.
*/
int
ext2fs_dirrewrite(struct inode *dp, const struct ufs_lookup_results *ulr,
struct inode *ip, struct componentname *cnp)
{
struct buf *bp;
struct ext2fs_direct *ep;
struct vnode *vdp = ITOV(dp);
int error;
error = ext2fs_blkatoff(vdp, (off_t)ulr->ulr_offset, (void *)&ep, &bp);
if (error != 0)
return (error);
ep->e2d_ino = h2fs32(ip->i_number);
if (ip->i_e2fs->e2fs.e2fs_rev > E2FS_REV0 &&
(ip->i_e2fs->e2fs.e2fs_features_incompat & EXT2F_INCOMPAT_FTYPE)) {
ep->e2d_type = inot2ext2dt(IFTODT(ip->i_e2fs_mode));
} else {
ep->e2d_type = 0;
}
error = VOP_BWRITE(bp->b_vp, bp);
dp->i_flag |= IN_CHANGE | IN_UPDATE;
return (error);
}
/*
* Convert a component of a pathname into a pointer to a locked inode.
* This is a very central and rather complicated routine.
* If the file system is not maintained in a strict tree hierarchy,
* this can result in a deadlock situation (see comments in code below).
*
* The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending
* on whether the name is to be looked up, created, renamed, or deleted.
* When CREATE, RENAME, or DELETE is specified, information usable in
* creating, renaming, or deleting a directory entry may be calculated.
* If flag has LOCKPARENT or'ed into it and the target of the pathname
* exists, lookup returns both the target and its parent directory locked.
* When creating or renaming and LOCKPARENT is specified, the target may
* not be ".". When deleting and LOCKPARENT is specified, the target may
* be "."., but the caller must check to ensure it does an vrele and vput
* instead of two vputs.
*
* Overall outline of ext2fs_lookup:
*
* check accessibility of directory
* look for name in cache, if found, then if at end of path
* and deleting or creating, drop it, else return name
* search for name in directory, to found or notfound
* notfound:
* if creating, return locked directory, leaving info on available slots
* else return error
* found:
* if at end of path and deleting, return information to allow delete
* if at end of path and rewriting (RENAME and LOCKPARENT), lock target
* inode and return info to allow rewrite
* if not at end, add name to cache; if at end and neither creating
* nor deleting, add name to cache
*/
int
ext2fs_lookup(void *v)
{
struct vop_lookup_v2_args /* {
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
} */ *ap = v;
struct vnode *vdp = ap->a_dvp; /* vnode for directory being searched */
struct inode *dp = VTOI(vdp); /* inode for directory being searched */
struct buf *bp; /* a buffer of directory entries */
struct ext2fs_direct *ep; /* the current directory entry */
int entryoffsetinblock; /* offset of ep in bp's buffer */
enum {NONE, COMPACT, FOUND} slotstatus;
doff_t slotoffset; /* offset of area with free space */
int slotsize; /* size of area at slotoffset */
int slotfreespace; /* amount of space free in slot */
int slotneeded; /* size of the entry we're seeking */
int numdirpasses; /* strategy for directory search */
doff_t endsearch; /* offset to end directory search */
doff_t prevoff; /* prev entry dp->i_offset */
struct vnode *tdp; /* returned by vcache_get */
doff_t enduseful; /* pointer past last used dir slot */
u_long bmask; /* block offset mask */
int namlen, error;
struct vnode **vpp = ap->a_vpp;
struct componentname *cnp = ap->a_cnp;
kauth_cred_t cred = cnp->cn_cred;
int flags;
int nameiop = cnp->cn_nameiop;
struct ufsmount *ump = dp->i_ump;
int dirblksiz = ump->um_dirblksiz;
ino_t foundino;
struct ufs_lookup_results *results;
flags = cnp->cn_flags;
bp = NULL;
slotoffset = -1;
*vpp = NULL;
/*
* Produce the auxiliary lookup results into i_crap. Increment
* its serial number so elsewhere we can tell if we're using
* stale results. This should not be done this way. XXX.
*/
results = &dp->i_crap;
dp->i_crapcounter++;
/*
* Check accessiblity of directory.
*/
if ((error = VOP_ACCESS(vdp, VEXEC, cred)) != 0)
return (error);
if ((flags & ISLASTCN) && (vdp->v_mount->mnt_flag & MNT_RDONLY) &&
(cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
return (EROFS);
/*
* We now have a segment name to search for, and a directory to search.
*
* Before tediously performing a linear scan of the directory,
* check the name cache to see if the directory/name pair
* we are looking for is known already.
*/
if (cache_lookup(vdp, cnp->cn_nameptr, cnp->cn_namelen,
cnp->cn_nameiop, cnp->cn_flags, NULL, vpp)) {
return *vpp == NULLVP ? ENOENT : 0;
}
/*
* Suppress search for slots unless creating
* file and at end of pathname, in which case
* we watch for a place to put the new file in
* case it doesn't already exist.
*/
slotstatus = FOUND;
slotfreespace = slotsize = slotneeded = 0;
if ((nameiop == CREATE || nameiop == RENAME) &&
(flags & ISLASTCN)) {
slotstatus = NONE;
slotneeded = EXT2FS_DIRSIZ(cnp->cn_namelen);
}
/*
* If there is cached information on a previous search of
* this directory, pick up where we last left off.
* We cache only lookups as these are the most common
* and have the greatest payoff. Caching CREATE has little
* benefit as it usually must search the entire directory
* to determine that the entry does not exist. Caching the
* location of the last DELETE or RENAME has not reduced
* profiling time and hence has been removed in the interest
* of simplicity.
*/
bmask = vdp->v_mount->mnt_stat.f_iosize - 1;
if (nameiop != LOOKUP || results->ulr_diroff == 0 ||
results->ulr_diroff >= ext2fs_size(dp)) {
entryoffsetinblock = 0;
results->ulr_offset = 0;
numdirpasses = 1;
} else {
results->ulr_offset = results->ulr_diroff;
if ((entryoffsetinblock = results->ulr_offset & bmask) &&
(error = ext2fs_blkatoff(vdp, (off_t)results->ulr_offset, NULL, &bp)))
return (error);
numdirpasses = 2;
namecache_count_2passes();
}
prevoff = results->ulr_offset;
endsearch = roundup(ext2fs_size(dp), dirblksiz);
enduseful = 0;
searchloop:
while (results->ulr_offset < endsearch) {
if (curcpu()->ci_schedstate.spc_flags & SPCF_SHOULDYIELD)
preempt();
/*
* If necessary, get the next directory block.
*/
if ((results->ulr_offset & bmask) == 0) {
if (bp != NULL)
brelse(bp, 0);
error = ext2fs_blkatoff(vdp, (off_t)results->ulr_offset, NULL,
&bp);
if (error != 0)
return (error);
entryoffsetinblock = 0;
}
/*
* If still looking for a slot, and at a dirblksize
* boundary, have to start looking for free space again.
*/
if (slotstatus == NONE &&
(entryoffsetinblock & (dirblksiz - 1)) == 0) {
slotoffset = -1;
slotfreespace = 0;
}
/*
* Get pointer to next entry.
* Full validation checks are slow, so we only check
* enough to insure forward progress through the
* directory. Complete checks can be run by patching
* "dirchk" to be true.
*/
KASSERT(bp != NULL);
ep = (struct ext2fs_direct *)
((char *)bp->b_data + entryoffsetinblock);
if (ep->e2d_reclen == 0 ||
(dirchk &&
ext2fs_dirbadentry(vdp, ep, entryoffsetinblock))) {
int i;
ufs_dirbad(dp, results->ulr_offset, "mangled entry");
i = dirblksiz - (entryoffsetinblock & (dirblksiz - 1));
results->ulr_offset += i;
entryoffsetinblock += i;
continue;
}
/*
* If an appropriate sized slot has not yet been found,
* check to see if one is available. Also accumulate space
* in the current block so that we can determine if
* compaction is viable.
*/
if (slotstatus != FOUND) {
int size = fs2h16(ep->e2d_reclen);
if (ep->e2d_ino != 0)
size -= EXT2FS_DIRSIZ(ep->e2d_namlen);
if (size > 0) {
if (size >= slotneeded) {
slotstatus = FOUND;
slotoffset = results->ulr_offset;
slotsize = fs2h16(ep->e2d_reclen);
} else if (slotstatus == NONE) {
slotfreespace += size;
if (slotoffset == -1)
slotoffset = results->ulr_offset;
if (slotfreespace >= slotneeded) {
slotstatus = COMPACT;
slotsize = results->ulr_offset +
fs2h16(ep->e2d_reclen) -
slotoffset;
}
}
}
}
/*
* Check for a name match.
*/
if (ep->e2d_ino) {
namlen = ep->e2d_namlen;
if (namlen == cnp->cn_namelen &&
!memcmp(cnp->cn_nameptr, ep->e2d_name,
(unsigned)namlen)) {
/*
* Save directory entry's inode number and
* reclen in ndp->ni_ufs area, and release
* directory buffer.
*/
foundino = fs2h32(ep->e2d_ino);
results->ulr_reclen = fs2h16(ep->e2d_reclen);
goto found;
}
}
prevoff = results->ulr_offset;
results->ulr_offset += fs2h16(ep->e2d_reclen);
entryoffsetinblock += fs2h16(ep->e2d_reclen);
if (ep->e2d_ino)
enduseful = results->ulr_offset;
}
/* notfound: */
/*
* If we started in the middle of the directory and failed
* to find our target, we must check the beginning as well.
*/
if (numdirpasses == 2) {
numdirpasses--;
results->ulr_offset = 0;
endsearch = results->ulr_diroff;
goto searchloop;
}
if (bp != NULL)
brelse(bp, 0);
/*
* If creating, and at end of pathname and current
* directory has not been removed, then can consider
* allowing file to be created.
*/
if ((nameiop == CREATE || nameiop == RENAME) &&
(flags & ISLASTCN) && dp->i_e2fs_nlink != 0) {
/*
* Access for write is interpreted as allowing
* creation of files in the directory.
*/
error = VOP_ACCESS(vdp, VWRITE, cred);
if (error)
return (error);
/*
* Return an indication of where the new directory
* entry should be put. If we didn't find a slot,
* then set results->ulr_count to 0 indicating
* that the new slot belongs at the end of the
* directory. If we found a slot, then the new entry
* can be put in the range from results->ulr_offset to
* results->ulr_offset + results->ulr_count.
*/
if (slotstatus == NONE) {
results->ulr_offset = roundup(ext2fs_size(dp), dirblksiz);
results->ulr_count = 0;
enduseful = results->ulr_offset;
} else {
results->ulr_offset = slotoffset;
results->ulr_count = slotsize;
if (enduseful < slotoffset + slotsize)
enduseful = slotoffset + slotsize;
}
results->ulr_endoff = roundup(enduseful, dirblksiz);
#if 0
dp->i_flag |= IN_CHANGE | IN_UPDATE;
#endif
/*
* We return with the directory locked, so that
* the parameters we set up above will still be
* valid if we actually decide to do a direnter().
* We return ni_vp == NULL to indicate that the entry
* does not currently exist; we leave a pointer to
* the (locked) directory inode in ndp->ni_dvp.
*
* NB - if the directory is unlocked, then this
* information cannot be used.
*/
return (EJUSTRETURN);
}
/*
* Insert name into cache (as non-existent) if appropriate.
*/
if (nameiop != CREATE) {
cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen,
cnp->cn_flags);
}
return ENOENT;
found:
if (numdirpasses == 2)
namecache_count_pass2();
/*
* Check that directory length properly reflects presence
* of this entry.
*/
if (results->ulr_offset + EXT2FS_DIRSIZ(ep->e2d_namlen) > ext2fs_size(dp)) {
ufs_dirbad(dp, results->ulr_offset, "i_size too small");
error = ext2fs_setsize(dp,
results->ulr_offset + EXT2FS_DIRSIZ(ep->e2d_namlen));
if (error) {
brelse(bp, 0);
return (error);
}
dp->i_flag |= IN_CHANGE | IN_UPDATE;
uvm_vnp_setsize(vdp, ext2fs_size(dp));
}
brelse(bp, 0);
/*
* Found component in pathname.
* If the final component of path name, save information
* in the cache as to where the entry was found.
*/
if ((flags & ISLASTCN) && nameiop == LOOKUP)
results->ulr_diroff = results->ulr_offset &~ (dirblksiz - 1);
/*
* If deleting, and at end of pathname, return
* parameters which can be used to remove file.
* Lock the inode, being careful with ".".
*/
if (nameiop == DELETE && (flags & ISLASTCN)) {
/*
* Return pointer to current entry in results->ulr_offset,
* and distance past previous entry (if there
* is a previous entry in this block) in results->ulr_count.
* Save directory inode pointer in ndp->ni_dvp for dirremove().
*/
if ((results->ulr_offset & (dirblksiz - 1)) == 0)
results->ulr_count = 0;
else
results->ulr_count = results->ulr_offset - prevoff;
if (dp->i_number == foundino) {
vref(vdp);
tdp = vdp;
} else {
error = vcache_get(vdp->v_mount,
&foundino, sizeof(foundino), &tdp);
if (error)
return (error);
}
/*
* Write access to directory required to delete files.
*/
if ((error = VOP_ACCESS(vdp, VWRITE, cred)) != 0) {
vrele(tdp);
return (error);
}
/*
* If directory is "sticky", then user must own
* the directory, or the file in it, else she
* may not delete it (unless she's root). This
* implements append-only directories.
*/
if (dp->i_e2fs_mode & ISVTX) {
error = kauth_authorize_vnode(cred, KAUTH_VNODE_DELETE,
tdp, vdp, genfs_can_sticky(cred, dp->i_uid,
VTOI(tdp)->i_uid));
if (error) {
vrele(tdp);
return (EPERM);
}
}
*vpp = tdp;
return (0);
}
/*
* If rewriting (RENAME), return the inode and the
* information required to rewrite the present directory
* Must get inode of directory entry to verify it's a
* regular file, or empty directory.
*/
if (nameiop == RENAME && (flags & ISLASTCN)) {
error = VOP_ACCESS(vdp, VWRITE, cred);
if (error)
return (error);
/*
* Careful about locking second inode.
* This can only occur if the target is ".".
*/
if (dp->i_number == foundino)
return (EISDIR);
error = vcache_get(vdp->v_mount,
&foundino, sizeof(foundino), &tdp);
if (error)
return (error);
*vpp = tdp;
return (0);
}
if (dp->i_number == foundino) {
vref(vdp); /* we want ourself, ie "." */
*vpp = vdp;
} else {
error = vcache_get(vdp->v_mount,
&foundino, sizeof(foundino), &tdp);
if (error)
return (error);
*vpp = tdp;
}
/*
* Insert name into cache if appropriate.
*/
cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_flags);
return 0;
}
/*
* Write a directory entry after a call to namei, using the parameters
* that it left in nameidata. The argument ip is the inode which the new
* directory entry will refer to. Dvp is a pointer to the directory to
* be written, which was left locked by namei. Remaining parameters
* (ulr_offset, ulr_count) indicate how the space for the new
* entry is to be obtained.
*/
int
ext2fs_direnter(struct inode *ip, struct vnode *dvp,
const struct ufs_lookup_results *ulr,
struct componentname *cnp)
{
struct ext2fs_direct *ep, *nep;
struct inode *dp;
struct buf *bp;
struct ext2fs_direct newdir;
struct iovec aiov;
struct uio auio;
u_int dsize;
int error, loc, newentrysize, spacefree;
char *dirbuf;
struct ufsmount *ump = VFSTOUFS(dvp->v_mount);
int dirblksiz = ump->um_dirblksiz;
dp = VTOI(dvp);
newdir.e2d_ino = h2fs32(ip->i_number);
newdir.e2d_namlen = cnp->cn_namelen;
if (ip->i_e2fs->e2fs.e2fs_rev > E2FS_REV0 &&
(ip->i_e2fs->e2fs.e2fs_features_incompat & EXT2F_INCOMPAT_FTYPE)) {
newdir.e2d_type = inot2ext2dt(IFTODT(ip->i_e2fs_mode));
} else {
newdir.e2d_type = 0;
}
memcpy(newdir.e2d_name, cnp->cn_nameptr, (unsigned)cnp->cn_namelen + 1);
newentrysize = EXT2FS_DIRSIZ(cnp->cn_namelen);
if (ulr->ulr_count == 0) {
/*
* If ulr_count is 0, then namei could find no
* space in the directory. Here, ulr_offset will
* be on a directory block boundary and we will write the
* new entry into a fresh block.
*/
if (ulr->ulr_offset & (dirblksiz - 1))
panic("ext2fs_direnter: newblk");
auio.uio_offset = ulr->ulr_offset;
newdir.e2d_reclen = h2fs16(dirblksiz);
auio.uio_resid = newentrysize;
aiov.iov_len = newentrysize;
aiov.iov_base = (void *)&newdir;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_rw = UIO_WRITE;
UIO_SETUP_SYSSPACE(&auio);
error = VOP_WRITE(dvp, &auio, IO_SYNC, cnp->cn_cred);
if (dirblksiz > dvp->v_mount->mnt_stat.f_bsize)
/* XXX should grow with balloc() */
panic("ext2fs_direnter: frag size");
else if (!error) {
error = ext2fs_setsize(dp,
roundup(ext2fs_size(dp), dirblksiz));
if (error)
return (error);
dp->i_flag |= IN_CHANGE;
uvm_vnp_setsize(dvp, ext2fs_size(dp));
}
return (error);
}
/*
* If ulr_count is non-zero, then namei found space
* for the new entry in the range ulr_offset to
* ulr_offset + ulr_count in the directory.
* To use this space, we may have to compact the entries located
* there, by copying them together towards the beginning of the
* block, leaving the free space in one usable chunk at the end.
*/
/*
* Get the block containing the space for the new directory entry.
*/
if ((error = ext2fs_blkatoff(dvp, (off_t)ulr->ulr_offset, &dirbuf, &bp)) != 0)
return (error);
/*
* Find space for the new entry. In the simple case, the entry at
* offset base will have the space. If it does not, then namei
* arranged that compacting the region ulr_offset to
* ulr_offset + ulr_count would yield the
* space.
*/
ep = (struct ext2fs_direct *)dirbuf;
dsize = EXT2FS_DIRSIZ(ep->e2d_namlen);
spacefree = fs2h16(ep->e2d_reclen) - dsize;
for (loc = fs2h16(ep->e2d_reclen); loc < ulr->ulr_count; ) {
nep = (struct ext2fs_direct *)(dirbuf + loc);
if (ep->e2d_ino) {
/* trim the existing slot */
ep->e2d_reclen = h2fs16(dsize);
ep = (struct ext2fs_direct *)((char *)ep + dsize);
} else {
/* overwrite; nothing there; header is ours */
spacefree += dsize;
}
dsize = EXT2FS_DIRSIZ(nep->e2d_namlen);
spacefree += fs2h16(nep->e2d_reclen) - dsize;
loc += fs2h16(nep->e2d_reclen);
memcpy((void *)ep, (void *)nep, dsize);
}
/*
* Update the pointer fields in the previous entry (if any),
* copy in the new entry, and write out the block.
*/
if (ep->e2d_ino == 0) {
#ifdef DIAGNOSTIC
if (spacefree + dsize < newentrysize)
panic("ext2fs_direnter: compact1");
#endif
newdir.e2d_reclen = h2fs16(spacefree + dsize);
} else {
#ifdef DIAGNOSTIC
if (spacefree < newentrysize) {
printf("ext2fs_direnter: compact2 %u %u",
(u_int)spacefree, (u_int)newentrysize);
panic("ext2fs_direnter: compact2");
}
#endif
newdir.e2d_reclen = h2fs16(spacefree);
ep->e2d_reclen = h2fs16(dsize);
ep = (struct ext2fs_direct *)((char *)ep + dsize);
}
memcpy((void *)ep, (void *)&newdir, (u_int)newentrysize);
error = VOP_BWRITE(bp->b_vp, bp);
dp->i_flag |= IN_CHANGE | IN_UPDATE;
if (!error && ulr->ulr_endoff && ulr->ulr_endoff < ext2fs_size(dp))
error = ext2fs_truncate(dvp, (off_t)ulr->ulr_endoff, IO_SYNC,
cnp->cn_cred);
return (error);
}
/*
* ext2fs_rename_recalculate_fulr: If we have just entered a directory
* into dvp at tulr, and we were about to remove one at fulr for an
* entry named fcnp, fulr may be invalid. So, if necessary,
* recalculate it.
*/
static int
ext2fs_rename_recalculate_fulr(struct vnode *dvp,
struct ufs_lookup_results *fulr, const struct ufs_lookup_results *tulr,
const struct componentname *fcnp)
{
struct mount *mp;
struct ufsmount *ump;
/* XXX int is a silly type for this; blame ufsmount::um_dirblksiz. */
int dirblksiz;
doff_t search_start, search_end;
doff_t offset; /* Offset of entry we're examining. */
struct buf *bp; /* I/O block we're examining. */
char *dirbuf; /* Pointer into directory at search_start. */
struct ext2fs_direct *ep; /* Pointer to the entry we're examining. */
/* XXX direct::d_reclen is 16-bit;
* ufs_lookup_results::ulr_reclen is 32-bit. Blah. */
uint32_t reclen; /* Length of the entry we're examining. */
uint32_t prev_reclen; /* Length of the preceding entry. */
int error;
KASSERT(dvp != NULL);
KASSERT(dvp->v_mount != NULL);
KASSERT(VTOI(dvp) != NULL);
KASSERT(fulr != NULL);
KASSERT(tulr != NULL);
KASSERT(fulr != tulr);
KASSERT(ext2fs_rename_ulr_overlap_p(fulr, tulr));
mp = dvp->v_mount;
ump = VFSTOUFS(mp);
KASSERT(ump != NULL);
KASSERT(ump == VTOI(dvp)->i_ump);
dirblksiz = ump->um_dirblksiz;
KASSERT(0 < dirblksiz);
KASSERT((dirblksiz & (dirblksiz - 1)) == 0);
/* A directory block may not span across multiple I/O blocks. */
KASSERT(dirblksiz <= mp->mnt_stat.f_iosize);
/* Find the bounds of the search. */
search_start = tulr->ulr_offset;
KASSERT(fulr->ulr_reclen < (EXT2FS_MAXDIRSIZE - fulr->ulr_offset));
search_end = (fulr->ulr_offset + fulr->ulr_reclen);
/* Compaction must happen only within a directory block. (*) */
KASSERT(search_start <= search_end);
KASSERT((search_end - (search_start &~ (dirblksiz - 1))) <= dirblksiz);
dirbuf = NULL;
bp = NULL;
error = ext2fs_blkatoff(dvp, (off_t)search_start, &dirbuf, &bp);
if (error)
return error;
KASSERT(dirbuf != NULL);
KASSERT(bp != NULL);
/*
* Guarantee we sha'n't go past the end of the buffer we got.
* dirbuf is bp->b_data + (search_start & (iosize - 1)), and
* the valid range is [bp->b_data, bp->b_data + bp->b_bcount).
*/
KASSERT((search_end - search_start) <=
(bp->b_bcount - (search_start & (mp->mnt_stat.f_iosize - 1))));
prev_reclen = fulr->ulr_count;
offset = search_start;
/*
* Search from search_start to search_end for the entry matching
* fcnp, which must be there because we found it before and it
* should only at most have moved earlier.
*/
for (;;) {
KASSERT(search_start <= offset);
KASSERT(offset < search_end);
/*
* Examine the directory entry at offset.
*/
ep = (struct ext2fs_direct *)
(dirbuf + (offset - search_start));
reclen = fs2h16(ep->e2d_reclen);
if (ep->e2d_ino == 0)
goto next; /* Entry is unused. */
if (fs2h32(ep->e2d_ino) == UFS_WINO)
goto next; /* Entry is whiteout. */
if (fcnp->cn_namelen != ep->e2d_namlen)
goto next; /* Wrong name length. */
if (memcmp(ep->e2d_name, fcnp->cn_nameptr, fcnp->cn_namelen))
goto next; /* Wrong name. */
/* Got it! */
break;
next:
if (! ((reclen < search_end) &&
(offset < (search_end - reclen)))) {
brelse(bp, 0);
return EIO; /* XXX Panic? What? */
}
/* We may not move past the search end. */
KASSERT(reclen < search_end);
KASSERT(offset < (search_end - reclen));
/*
* We may not move across a directory block boundary;
* see (*) above.
*/
KASSERT((offset &~ (dirblksiz - 1)) ==
((offset + reclen) &~ (dirblksiz - 1)));
prev_reclen = reclen;
offset += reclen;
}
/*
* Found the entry. Record where.
*/
fulr->ulr_offset = offset;
fulr->ulr_reclen = reclen;
/*
* Record the preceding record length, but not if we're at the
* start of a directory block.
*/
fulr->ulr_count = ((offset & (dirblksiz - 1))? prev_reclen : 0);
brelse(bp, 0);
return 0;
}