/* $NetBSD: ulfs_lookup.c,v 1.47 2022/08/06 18:26:42 andvar Exp $ */
/* from NetBSD: ufs_lookup.c,v 1.135 2015/07/11 11:04:48 mlelstv */
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)ufs_lookup.c 8.9 (Berkeley) 8/11/94
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ulfs_lookup.c,v 1.47 2022/08/06 18:26:42 andvar Exp $");
#ifdef _KERNEL_OPT
#include "opt_lfs.h"
#endif
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/namei.h>
#include <sys/buf.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/kernel.h>
#include <sys/kauth.h>
#include <sys/proc.h>
#include <sys/kmem.h>
#include <ufs/lfs/lfs.h>
#include <ufs/lfs/lfs_accessors.h>
#include <ufs/lfs/lfs_extern.h>
#include <ufs/lfs/ulfs_inode.h>
#ifdef LFS_DIRHASH
#include <ufs/lfs/ulfs_dirhash.h>
#endif
#include <ufs/lfs/ulfsmount.h>
#include <ufs/lfs/ulfs_extern.h>
#include <ufs/lfs/ulfs_bswap.h>
#include <miscfs/genfs/genfs.h>
#ifdef DIAGNOSTIC
int lfs_dirchk = 1;
#else
int lfs_dirchk = 0;
#endif
/*
* 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 ulfs_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
ulfs_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 */
LFS_DIRHEADER *ep; /* the current directory entry */
int entryoffsetinblock; /* offset of ep in bp's buffer */
enum {
NONE, /* need to search a slot for our new entry */
COMPACT, /* a compaction can make a slot in the current
DIRBLKSIZ block */
FOUND, /* found a slot (or no need to search) */
} slotstatus;
doff_t slotoffset; /* offset of area with free space.
a special value -1 for invalid */
int slotsize; /* size of area at slotoffset */
int slotfreespace; /* accumulated amount of space free in
the current DIRBLKSIZ block */
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; /* previous value of ulr_offset */
struct vnode *tdp; /* returned by vcache_get */
doff_t enduseful; /* pointer past last used dir slot.
used for directory truncation. */
u_long bmask; /* block offset mask */
int 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 lfs *fs = dp->i_lfs;
int dirblksiz = fs->um_dirblksiz;
ino_t foundino;
struct ulfs_lookup_results *results;
int iswhiteout; /* temp result from cache_lookup() */
flags = cnp->cn_flags;
bp = NULL;
slotoffset = -1;
*vpp = NULL;
endsearch = 0; /* silence compiler warning */
/*
* Check accessibility of directory.
*/
if ((error = VOP_ACCESS(vdp, VEXEC, cred)) != 0)
return (error);
if ((flags & ISLASTCN) && (vdp->v_mount->mnt_flag & MNT_RDONLY) &&
(nameiop == DELETE || 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, &iswhiteout, vpp)) {
if (iswhiteout) {
cnp->cn_flags |= ISWHITEOUT;
}
return *vpp == NULLVP ? ENOENT : 0;
}
/* May need to restart the lookup with an exclusive lock. */
if (VOP_ISLOCKED(vdp) != LK_EXCLUSIVE)
return ENOLCK;
/*
* 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++;
if (iswhiteout) {
/*
* The namecache set iswhiteout without finding a
* cache entry. As of this writing (20121014), this
* can happen if there was a whiteout entry that has
* been invalidated by the lookup. It is not clear if
* it is correct to set ISWHITEOUT in this case or
* not; however, doing so retains the prior behavior,
* so we'll go with that until some clearer answer
* appears. XXX
*/
cnp->cn_flags |= ISWHITEOUT;
}
/*
* 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 = LFS_DIRECTSIZ(fs, 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;
#ifdef LFS_DIRHASH
/*
* Use dirhash for fast operations on large directories. The logic
* to determine whether to hash the directory is contained within
* ulfsdirhash_build(); a zero return means that it decided to hash
* this directory and it successfully built up the hash table.
*/
if (ulfsdirhash_build(dp) == 0) {
/* Look for a free slot if needed. */
enduseful = dp->i_size;
if (slotstatus != FOUND) {
slotoffset = ulfsdirhash_findfree(dp, slotneeded,
&slotsize);
if (slotoffset >= 0) {
slotstatus = COMPACT;
enduseful = ulfsdirhash_enduseful(dp);
if (enduseful < 0)
enduseful = dp->i_size;
}
}
/* Look up the component. */
numdirpasses = 1;
entryoffsetinblock = 0; /* silence compiler warning */
switch (ulfsdirhash_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen,
&results->ulr_offset, &bp, nameiop == DELETE ? &prevoff : NULL)) {
case 0:
ep = (LFS_DIRHEADER *)((char *)bp->b_data +
(results->ulr_offset & bmask));
goto foundentry;
case ENOENT:
results->ulr_offset = roundup(dp->i_size, dirblksiz);
goto notfound;
default:
/* Something failed; just do a linear search. */
break;
}
}
#endif /* LFS_DIRHASH */
if (nameiop != LOOKUP || results->ulr_diroff == 0 ||
results->ulr_diroff >= dp->i_size) {
entryoffsetinblock = 0;
results->ulr_offset = 0;
numdirpasses = 1;
} else {
results->ulr_offset = results->ulr_diroff;
if ((entryoffsetinblock = results->ulr_offset & bmask) &&
(error = ulfs_blkatoff(vdp, (off_t)results->ulr_offset,
NULL, &bp, false)))
goto out;
numdirpasses = 2;
namecache_count_2passes();
}
prevoff = results->ulr_offset;
endsearch = roundup(dp->i_size, dirblksiz);
enduseful = 0;
searchloop:
while (results->ulr_offset < endsearch) {
preempt_point();
/*
* If necessary, get the next directory block.
*/
if ((results->ulr_offset & bmask) == 0) {
if (bp != NULL)
brelse(bp, 0);
error = ulfs_blkatoff(vdp, (off_t)results->ulr_offset,
NULL, &bp, false);
if (error)
goto out;
entryoffsetinblock = 0;
}
/*
* If still looking for a slot, and at a DIRBLKSIZ
* 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
* "lfs_dirchk" to be true.
*/
KASSERT(bp != NULL);
ep = (LFS_DIRHEADER *)((char *)bp->b_data + entryoffsetinblock);
if (lfs_dir_getreclen(fs, ep) == 0 ||
(lfs_dirchk && ulfs_dirbadentry(vdp, ep, entryoffsetinblock))) {
int i;
ulfs_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 = lfs_dir_getreclen(fs, ep);
if (lfs_dir_getino(fs, ep) != 0)
size -= LFS_DIRSIZ(fs, ep);
if (size > 0) {
if (size >= slotneeded) {
slotstatus = FOUND;
slotoffset = results->ulr_offset;
slotsize = lfs_dir_getreclen(fs, ep);
} else if (slotstatus == NONE) {
slotfreespace += size;
if (slotoffset == -1)
slotoffset = results->ulr_offset;
if (slotfreespace >= slotneeded) {
slotstatus = COMPACT;
slotsize = results->ulr_offset +
lfs_dir_getreclen(fs, ep) -
slotoffset;
}
}
}
}
/*
* Check for a name match.
*/
if (lfs_dir_getino(fs, ep)) {
int namlen;
namlen = lfs_dir_getnamlen(fs, ep);
if (namlen == cnp->cn_namelen &&
!memcmp(cnp->cn_nameptr, lfs_dir_nameptr(fs, ep),
(unsigned)namlen)) {
#ifdef LFS_DIRHASH
foundentry:
#endif
/*
* Save directory entry's inode number and
* reclen, and release directory buffer.
*/
if (!FSFMT(vdp) && lfs_dir_gettype(fs, ep) == LFS_DT_WHT) {
slotstatus = FOUND;
slotoffset = results->ulr_offset;
slotsize = lfs_dir_getreclen(fs, ep);
results->ulr_reclen = slotsize;
/*
* This is used to set
* results->ulr_endoff,
* which may be used by ulfs_direnter()
* as a length to truncate the
* directory to. Therefore, it must
* point past the end of the last
* non-empty directory entry. We don't
* know where that is in this case, so
* we effectively disable shrinking by
* using the existing size of the
* directory.
*
* Note that we wouldn't expect to
* shrink the directory while rewriting
* an existing entry anyway.
*/
enduseful = endsearch;
cnp->cn_flags |= ISWHITEOUT;
numdirpasses--;
goto notfound;
}
foundino = lfs_dir_getino(fs, ep);
results->ulr_reclen = lfs_dir_getreclen(fs, ep);
goto found;
}
}
prevoff = results->ulr_offset;
results->ulr_offset += lfs_dir_getreclen(fs, ep);
entryoffsetinblock += lfs_dir_getreclen(fs, ep);
if (lfs_dir_getino(fs, ep))
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 ||
(nameiop == DELETE &&
(cnp->cn_flags & DOWHITEOUT) &&
(cnp->cn_flags & ISWHITEOUT))) &&
(flags & ISLASTCN) && dp->i_nlink != 0) {
/*
* Access for write is interpreted as allowing
* creation of files in the directory.
*/
error = VOP_ACCESS(vdp, VWRITE, cred);
if (error)
goto out;
/*
* 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(dp->i_size, dirblksiz);
results->ulr_count = 0;
enduseful = results->ulr_offset;
} else if (nameiop == DELETE) {
results->ulr_offset = slotoffset;
if ((results->ulr_offset & (dirblksiz - 1)) == 0)
results->ulr_count = 0;
else
results->ulr_count =
results->ulr_offset - prevoff;
} else {
results->ulr_offset = slotoffset;
results->ulr_count = slotsize;
if (enduseful < slotoffset + slotsize)
enduseful = slotoffset + slotsize;
}
results->ulr_endoff = roundup(enduseful, dirblksiz);
#if 0 /* commented out by dbj. none of the on disk fields changed */
dp->i_state |= 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.
*/
error = EJUSTRETURN;
goto out;
}
/*
* 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);
}
error = ENOENT;
goto out;
found:
if (numdirpasses == 2)
namecache_count_pass2();
/*
* Check that directory length properly reflects presence
* of this entry.
*/
if (results->ulr_offset + LFS_DIRSIZ(fs, ep) > dp->i_size) {
ulfs_dirbad(dp, results->ulr_offset, "i_size too small");
dp->i_size =
results->ulr_offset + LFS_DIRSIZ(fs, ep);
DIP_ASSIGN(dp, size, dp->i_size);
dp->i_state |= IN_CHANGE | IN_UPDATE;
}
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)
goto out;
}
/*
* Write access to directory required to delete files.
*/
error = VOP_ACCESS(vdp, VWRITE, cred);
if (error) {
vrele(tdp);
goto out;
}
/*
* 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_mode & ISVTX) {
error = kauth_authorize_vnode(cred, KAUTH_VNODE_DELETE,
tdp, vdp, genfs_can_sticky(vdp, cred, dp->i_uid,
VTOI(tdp)->i_uid));
if (error) {
vrele(tdp);
error = EPERM;
goto out;
}
}
*vpp = tdp;
error = 0;
goto out;
}
/*
* 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)
goto out;
/*
* Careful about locking second inode.
* This can only occur if the target is ".".
*/
if (dp->i_number == foundino) {
error = EISDIR;
goto out;
}
error = vcache_get(vdp->v_mount,
&foundino, sizeof(foundino), &tdp);
if (error)
goto out;
*vpp = tdp;
error = 0;
goto out;
}
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)
goto out;
*vpp = tdp;
}
/*
* Insert name into cache if appropriate.
*/
cache_enter(vdp, *vpp, cnp->cn_nameptr, cnp->cn_namelen, cnp->cn_flags);
error = 0;
out:
return error;
}
void
ulfs_dirbad(struct inode *ip, doff_t offset, const char *how)
{
struct mount *mp;
mp = ITOV(ip)->v_mount;
printf("%s: bad dir ino %llu at offset %d: %s\n",
mp->mnt_stat.f_mntonname, (unsigned long long)ip->i_number,
offset, how);
if ((mp->mnt_flag & MNT_RDONLY) == 0)
panic("bad dir");
}
/*
* Do consistency checking on a directory entry:
* record length must be multiple of 4
* entry must fit in rest of its DIRBLKSIZ block
* record must be large enough to contain entry
* name is not longer than LFS_MAXNAMLEN
* name must be as long as advertised, and null terminated
*/
int
ulfs_dirbadentry(struct vnode *dp, LFS_DIRHEADER *ep, int entryoffsetinblock)
{
int i;
int namlen;
unsigned reclen;
struct ulfsmount *ump = VFSTOULFS(dp->v_mount);
struct lfs *fs = ump->um_lfs;
int dirblksiz = fs->um_dirblksiz;
const char *name;
namlen = lfs_dir_getnamlen(fs, ep);
reclen = lfs_dir_getreclen(fs, ep);
if ((reclen & 0x3) != 0 ||
reclen > dirblksiz - (entryoffsetinblock & (dirblksiz - 1)) ||
reclen < LFS_DIRSIZ(fs, ep) || namlen > LFS_MAXNAMLEN) {
/*return (1); */
printf("First bad, reclen=%#x, DIRSIZ=%lu, namlen=%d, "
"flags=%#x, entryoffsetinblock=%d, dirblksiz = %d\n",
lfs_dir_getreclen(fs, ep),
(u_long)LFS_DIRSIZ(fs, ep),
namlen, dp->v_mount->mnt_flag, entryoffsetinblock,
dirblksiz);
goto bad;
}
if (lfs_dir_getino(fs, ep) == 0)
return (0);
name = lfs_dir_nameptr(fs, ep);
for (i = 0; i < namlen; i++)
if (name[i] == '\0') {
/*return (1); */
printf("Second bad\n");
goto bad;
}
if (name[i])
goto bad;
return (0);
bad:
return (1);
}
/*
* Assign the contents of directory entry DIRP, on volume FS.
*
* NAME/NAMLEN is the name, which is not necessarily null terminated.
* INUM is the inode number, and DTYPE is the type code (LFS_DT_*).
*
* Note that these values typically come from:
* cnp->cn_nameptr
* cnp->cn_namelen
* ip->i_number
* LFS_IFTODT(ip->i_mode)
*
* Does not set d_reclen.
*/
static void
ulfs_direntry_assign(struct lfs *fs, LFS_DIRHEADER *dirp,
const char *name, size_t namlen,
ino_t inum, unsigned dtype)
{
lfs_dir_setino(fs, dirp, inum);
lfs_dir_setnamlen(fs, dirp, namlen);
lfs_dir_settype(fs, dirp, dtype);
memcpy(lfs_dir_nameptr(fs, dirp), name, namlen);
lfs_dir_nameptr(fs, dirp)[namlen] = '\0';
}
/*
* Write a directory entry after a call to namei, using the parameters
* that ulfs_lookup left in nameidata and in the ulfs_lookup_results.
*
* DVP is the directory to be updated. It must be locked.
* ULR is the ulfs_lookup_results structure from the final lookup step.
* TVP is not used. (XXX: why is it here? remove it)
* CNP is the componentname from the final lookup step.
* INUM is the inode number to insert into the new directory entry.
* DTYPE is the type code (LFS_DT_*) to insert into the new directory entry.
* NEWDIRBP is not used and (XXX) should be removed. The previous
* comment here said it was used by the now-removed softupdates code.
*
* The link count of the target inode is *not* incremented; the
* caller does that.
*
* If ulr->ulr_count is 0, ulfs_lookup did not find space to insert the
* directory entry. ulr_offset, which is the place to put the entry,
* should be on a block boundary (and should be at the end of the
* directory AFAIK) and a fresh block is allocated to put the new
* directory entry in.
*
* If ulr->ulr_count is not zero, ulfs_lookup found a slot to insert
* the entry into. This slot ranges from ulr_offset to ulr_offset +
* ulr_count. However, this slot may already be partially populated
* requiring compaction. See notes below.
*
* Furthermore, if ulr_count is not zero and ulr_endoff is not the
* same as i_size, the directory is truncated to size ulr_endoff.
*/
int
ulfs_direnter(struct vnode *dvp, const struct ulfs_lookup_results *ulr,
struct vnode *tvp,
struct componentname *cnp, ino_t inum, unsigned dtype,
struct buf *newdirbp)
{
kauth_cred_t cr;
int newentrysize;
struct inode *dp;
struct buf *bp;
u_int dsize;
LFS_DIRHEADER *ep, *nep;
int error, ret, lfs_blkoff, loc, spacefree;
char *dirbuf;
struct timespec ts;
struct ulfsmount *ump = VFSTOULFS(dvp->v_mount);
struct lfs *fs = ump->um_lfs;
int dirblksiz = fs->um_dirblksiz;
const char *name;
unsigned namlen, reclen;
#ifdef LFS_DIRHASH
int dohashadd;
#endif
error = 0;
name = cnp->cn_nameptr; /* note: not null-terminated */
namlen = cnp->cn_namelen;
cr = cnp->cn_cred;
dp = VTOI(dvp);
newentrysize = LFS_DIRECTSIZ(fs, namlen);
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("ulfs_direnter: newblk");
if ((error = lfs_balloc(dvp, (off_t)ulr->ulr_offset, dirblksiz,
cr, B_CLRBUF | B_SYNC, &bp)) != 0) {
return (error);
}
dp->i_size = ulr->ulr_offset + dirblksiz;
DIP_ASSIGN(dp, size, dp->i_size);
dp->i_state |= IN_CHANGE | IN_UPDATE;
uvm_vnp_setsize(dvp, dp->i_size);
lfs_blkoff = ulr->ulr_offset & (ump->um_mountp->mnt_stat.f_iosize - 1);
ep = (LFS_DIRHEADER *)((char *)bp->b_data + lfs_blkoff);
ulfs_direntry_assign(fs, ep, name, namlen, inum, dtype);
lfs_dir_setreclen(fs, ep, dirblksiz);
#ifdef LFS_DIRHASH
if (dp->i_dirhash != NULL) {
ulfsdirhash_newblk(dp, ulr->ulr_offset);
ulfsdirhash_add(dp, ep, ulr->ulr_offset);
ulfsdirhash_checkblock(dp, (char *)bp->b_data + lfs_blkoff,
ulr->ulr_offset);
}
#endif
error = VOP_BWRITE(bp->b_vp, bp);
vfs_timestamp(&ts);
ret = lfs_update(dvp, &ts, &ts, UPDATE_DIROP);
if (error == 0)
return (ret);
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.
*/
/*
* Increase size of directory if entry eats into new space.
* This should never push the size past a new multiple of
* DIRBLKSIZ.
*
* N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN.
*/
if (ulr->ulr_offset + ulr->ulr_count > dp->i_size) {
#ifdef DIAGNOSTIC
printf("ulfs_direnter: reached 4.2-only block, "
"not supposed to happen\n");
#endif
dp->i_size = ulr->ulr_offset + ulr->ulr_count;
DIP_ASSIGN(dp, size, dp->i_size);
dp->i_state |= IN_CHANGE | IN_UPDATE;
}
/*
* Get the block containing the space for the new directory entry.
*/
error = ulfs_blkatoff(dvp, (off_t)ulr->ulr_offset, &dirbuf, &bp, true);
if (error) {
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 = (LFS_DIRHEADER *)dirbuf;
dsize = (lfs_dir_getino(fs, ep) != 0) ? LFS_DIRSIZ(fs, ep) : 0;
spacefree = lfs_dir_getreclen(fs, ep) - dsize;
for (loc = lfs_dir_getreclen(fs, ep); loc < ulr->ulr_count; ) {
nep = (LFS_DIRHEADER *)(dirbuf + loc);
/* Trim the existing slot (NB: dsize may be zero). */
lfs_dir_setreclen(fs, ep, dsize);
ep = LFS_NEXTDIR(fs, ep);
reclen = lfs_dir_getreclen(fs, nep);
loc += reclen;
if (lfs_dir_getino(fs, nep) == 0) {
/*
* A mid-block unused entry. Such entries are
* never created by the kernel, but fsck_ffs
* can create them (and it doesn't fix them).
*
* Add up the free space, and initialise the
* relocated entry since we don't memcpy it.
*/
spacefree += reclen;
lfs_dir_setino(fs, ep, 0);
dsize = 0;
continue;
}
dsize = LFS_DIRSIZ(fs, nep);
spacefree += reclen - dsize;
#ifdef LFS_DIRHASH
if (dp->i_dirhash != NULL)
ulfsdirhash_move(dp, nep,
ulr->ulr_offset + ((char *)nep - dirbuf),
ulr->ulr_offset + ((char *)ep - dirbuf));
#endif
memcpy((void *)ep, (void *)nep, dsize);
}
/*
* Here, `ep' points to a directory entry containing `dsize' in-use
* bytes followed by `spacefree' unused bytes. If ep->d_ino == 0,
* then the entry is completely unused (dsize == 0). The value
* of ep->d_reclen is always indeterminate.
*
* Update the pointer fields in the previous entry (if any),
* copy in the new entry, and write out the block.
*/
if (lfs_dir_getino(fs, ep) == 0 ||
(lfs_dir_getino(fs, ep) == ULFS_WINO &&
memcmp(lfs_dir_nameptr(fs, ep), name, namlen) == 0)) {
if (spacefree + dsize < newentrysize)
panic("ulfs_direnter: compact1");
reclen = spacefree + dsize;
#ifdef LFS_DIRHASH
dohashadd = (lfs_dir_getino(fs, ep) == 0);
#endif
} else {
if (spacefree < newentrysize)
panic("ulfs_direnter: compact2");
reclen = spacefree;
lfs_dir_setreclen(fs, ep, dsize);
ep = LFS_NEXTDIR(fs, ep);
#ifdef LFS_DIRHASH
dohashadd = 1;
#endif
}
ulfs_direntry_assign(fs, ep, name, namlen, inum, dtype);
lfs_dir_setreclen(fs, ep, reclen);
#ifdef LFS_DIRHASH
if (dp->i_dirhash != NULL && dohashadd)
ulfsdirhash_add(dp, ep, ulr->ulr_offset + ((char *)ep - dirbuf));
if (dp->i_dirhash != NULL)
ulfsdirhash_checkblock(dp, dirbuf -
(ulr->ulr_offset & (dirblksiz - 1)),
ulr->ulr_offset & ~(dirblksiz - 1));
#endif
error = VOP_BWRITE(bp->b_vp, bp);
dp->i_state |= IN_CHANGE | IN_UPDATE;
/*
* If all went well, and the directory can be shortened, proceed
* with the truncation. Note that we have to unlock the inode for
* the entry that we just entered, as the truncation may need to
* lock other inodes which can lead to deadlock if we also hold a
* lock on the newly entered node.
*/
if (error == 0 && ulr->ulr_endoff && ulr->ulr_endoff < dp->i_size) {
#ifdef LFS_DIRHASH
if (dp->i_dirhash != NULL)
ulfsdirhash_dirtrunc(dp, ulr->ulr_endoff);
#endif
(void) lfs_truncate(dvp, (off_t)ulr->ulr_endoff, IO_SYNC, cr);
}
return (error);
}
/*
* Remove a directory entry after a call to namei, using the
* parameters that ulfs_lookup left in nameidata and in the
* ulfs_lookup_results.
*
* DVP is the directory to be updated. It must be locked.
* ULR is the ulfs_lookup_results structure from the final lookup step.
* IP, if not null, is the inode being unlinked.
* FLAGS may contain DOWHITEOUT.
* ISRMDIR is not used and (XXX) should be removed.
*
* If FLAGS contains DOWHITEOUT the entry is replaced with a whiteout
* instead of being cleared.
*
* ulr->ulr_offset contains the position of the directory entry
* to be removed.
*
* ulr->ulr_reclen contains the size of the directory entry to be
* removed.
*
* ulr->ulr_count contains the size of the *previous* directory
* entry. This allows finding it, for free space management. If
* ulr_count is 0, the target entry is at the beginning of the
* directory. (Does this ever happen? The first entry should be ".",
* which should only be removed at rmdir time. Does rmdir come here
* to clear out the "." and ".." entries? Perhaps, but I doubt it.)
*
* The space is marked free by adding it to the record length (not
* name length) of the preceding entry. If the first entry becomes
* free, it is marked free by setting the inode number to 0.
*
* The link count of IP is decremented. Note that this is not the
* inverse behavior of ulfs_direnter, which does not adjust link
* counts. Sigh.
*/
int
ulfs_dirremove(struct vnode *dvp, const struct ulfs_lookup_results *ulr,
struct inode *ip, int flags, int isrmdir)
{
struct inode *dp = VTOI(dvp);
struct lfs *fs = dp->i_lfs;
LFS_DIRHEADER *ep;
struct buf *bp;
int error;
if (flags & DOWHITEOUT) {
/*
* Whiteout entry: set d_ino to ULFS_WINO.
*/
error = ulfs_blkatoff(dvp, (off_t)ulr->ulr_offset, (void *)&ep,
&bp, true);
if (error)
return (error);
lfs_dir_setino(fs, ep, ULFS_WINO);
lfs_dir_settype(fs, ep, LFS_DT_WHT);
goto out;
}
if ((error = ulfs_blkatoff(dvp,
(off_t)(ulr->ulr_offset - ulr->ulr_count), (void *)&ep, &bp, true)) != 0)
return (error);
#ifdef LFS_DIRHASH
/*
* Remove the dirhash entry. This is complicated by the fact
* that `ep' is the previous entry when ulr_count != 0.
*/
if (dp->i_dirhash != NULL)
ulfsdirhash_remove(dp, (ulr->ulr_count == 0) ? ep :
LFS_NEXTDIR(fs, ep), ulr->ulr_offset);
#endif
if (ulr->ulr_count == 0) {
/*
* First entry in block: set d_ino to zero.
*/
lfs_dir_setino(fs, ep, 0);
} else {
/*
* Collapse new free space into previous entry.
*/
lfs_dir_setreclen(fs, ep,
lfs_dir_getreclen(fs, ep) + ulr->ulr_reclen);
}
#ifdef LFS_DIRHASH
if (dp->i_dirhash != NULL) {
int dirblksiz = ip->i_lfs->um_dirblksiz;
ulfsdirhash_checkblock(dp, (char *)ep -
((ulr->ulr_offset - ulr->ulr_count) & (dirblksiz - 1)),
ulr->ulr_offset & ~(dirblksiz - 1));
}
#endif
out:
if (ip) {
ip->i_nlink--;
DIP_ASSIGN(ip, nlink, ip->i_nlink);
ip->i_state |= IN_CHANGE;
}
/*
* XXX did it ever occur to anyone that it might be a good
* idea to restore ip->i_nlink if this fails? Or something?
* Currently on error return from this function the state of
* ip->i_nlink depends on what happened, and callers
* definitely do not take this into account.
*/
error = VOP_BWRITE(bp->b_vp, bp);
dp->i_state |= IN_CHANGE | IN_UPDATE;
/*
* If the last named reference to a snapshot goes away,
* drop its snapshot reference so that it will be reclaimed
* when last open reference goes away.
*/
if (ip != 0 && (ip->i_flags & SF_SNAPSHOT) != 0 &&
ip->i_nlink == 0)
ulfs_snapgone(ip);
return (error);
}
/*
* Rewrite an existing directory entry to point at the inode supplied.
*
* DP is the directory to update.
* OFFSET is the position of the entry in question. It may come
* from ulr_offset of a ulfs_lookup_results.
* OIP is the old inode the directory previously pointed to.
* NEWINUM is the number of the new inode.
* NEWTYPE is the new value for the type field of the directory entry.
* (This is ignored if the fs doesn't support that.)
* ISRMDIR is not used and (XXX) should be removed.
* IFLAGS are added to DP's inode flags.
*
* The link count of OIP is decremented. Note that the link count of
* the new inode is *not* incremented. Yay for symmetry.
*/
int
ulfs_dirrewrite(struct inode *dp, off_t offset,
struct inode *oip, ino_t newinum, int newtype,
int isrmdir, int iflags)
{
struct lfs *fs = dp->i_lfs;
struct buf *bp;
LFS_DIRHEADER *ep;
struct vnode *vdp = ITOV(dp);
int error;
error = ulfs_blkatoff(vdp, offset, (void *)&ep, &bp, true);
if (error)
return (error);
lfs_dir_setino(fs, ep, newinum);
lfs_dir_settype(fs, ep, newtype);
oip->i_nlink--;
DIP_ASSIGN(oip, nlink, oip->i_nlink);
oip->i_state |= IN_CHANGE;
error = VOP_BWRITE(bp->b_vp, bp);
dp->i_state |= iflags;
/*
* If the last named reference to a snapshot goes away,
* drop its snapshot reference so that it will be reclaimed
* when last open reference goes away.
*/
if ((oip->i_flags & SF_SNAPSHOT) != 0 && oip->i_nlink == 0)
ulfs_snapgone(oip);
return (error);
}
/*
* Check if a directory is empty or not.
* Inode supplied must be locked.
*
* Using a struct lfs_dirtemplate here is not precisely
* what we want, but better than using a struct lfs_direct.
*
* NB: does not handle corrupted directories.
*/
int
ulfs_dirempty(struct inode *ip, ino_t parentino, kauth_cred_t cred)
{
struct lfs *fs = ip->i_lfs;
doff_t off;
union lfs_dirtemplate dbuf;
LFS_DIRHEADER *dp = (LFS_DIRHEADER *)&dbuf;
int error, namlen;
const char *name;
size_t count;
/* XXX this should probably use LFS_DIRECTSIZ(fs, 2) */
#define MINDIRSIZ (sizeof (struct lfs_dirtemplate64) / 2)
for (off = 0; off < ip->i_size; off += lfs_dir_getreclen(fs, dp)) {
error = ulfs_bufio(UIO_READ, ITOV(ip), (void *)dp, MINDIRSIZ,
off, IO_NODELOCKED, cred, &count, NULL);
/*
* Since we read MINDIRSIZ, residual must
* be 0 unless we're at end of file.
*/
if (error || count != 0)
return (0);
/* avoid infinite loops */
if (lfs_dir_getreclen(fs, dp) == 0)
return (0);
/* skip empty entries */
if (lfs_dir_getino(fs, dp) == 0 ||
lfs_dir_getino(fs, dp) == ULFS_WINO)
continue;
/* accept only "." and ".." */
namlen = lfs_dir_getnamlen(fs, dp);
name = lfs_dir_nameptr(fs, dp);
if (namlen > 2)
return (0);
if (name[0] != '.')
return (0);
/*
* At this point namlen must be 1 or 2.
* 1 implies ".", 2 implies ".." if second
* char is also "."
*/
if (namlen == 1 && lfs_dir_getino(fs, dp) == ip->i_number)
continue;
if (name[1] == '.' && lfs_dir_getino(fs, dp) == parentino)
continue;
return (0);
}
return (1);
}
#define ULFS_DIRRABLKS 0
int ulfs_dirrablks = ULFS_DIRRABLKS;
/*
* ulfs_blkatoff: Return buffer with the contents of block "offset" from
* the beginning of directory "vp". If "res" is non-NULL, fill it in with
* a pointer to the remaining space in the directory. If the caller intends
* to modify the buffer returned, "modify" must be true.
*/
int
ulfs_blkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp,
bool modify)
{
struct inode *ip __diagused;
struct buf *bp;
daddr_t lbn;
const int dirrablks = ulfs_dirrablks;
daddr_t *blks;
int *blksizes;
int run, error;
struct mount *mp = vp->v_mount;
const int bshift = mp->mnt_fs_bshift;
const int bsize = 1 << bshift;
off_t eof;
blks = kmem_alloc((1 + dirrablks) * sizeof(daddr_t), KM_SLEEP);
blksizes = kmem_alloc((1 + dirrablks) * sizeof(int), KM_SLEEP);
ip = VTOI(vp);
KASSERT(vp->v_size == ip->i_size);
GOP_SIZE(vp, vp->v_size, &eof, 0);
lbn = offset >> bshift;
for (run = 0; run <= dirrablks;) {
const off_t curoff = lbn << bshift;
const int size = MIN(eof - curoff, bsize);
if (size == 0) {
break;
}
KASSERT(curoff < eof);
blks[run] = lbn;
blksizes[run] = size;
lbn++;
run++;
if (size != bsize) {
break;
}
}
KASSERT(run >= 1);
error = breadn(vp, blks[0], blksizes[0], &blks[1], &blksizes[1],
run - 1, (modify ? B_MODIFY : 0), &bp);
if (error != 0) {
*bpp = NULL;
goto out;
}
if (res) {
*res = (char *)bp->b_data + (offset & (bsize - 1));
}
*bpp = bp;
out:
kmem_free(blks, (1 + dirrablks) * sizeof(daddr_t));
kmem_free(blksizes, (1 + dirrablks) * sizeof(int));
return error;
}