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freebsd-nq/sys/ufs/ufs/ufs_lookup.c
Julian Elischer b40ce4165d KSE Milestone 2 
Note ALL MODULES MUST BE RECOMPILED
make the kernel aware that there are smaller units of scheduling than the
process. (but only allow one thread per process at this time).
This is functionally equivalent to teh previousl -current except
that there is a thread associated with each process.

Sorry john! (your next MFC will be a doosie!)

Reviewed by: peter@freebsd.org, dillon@freebsd.org

X-MFC after:    ha ha ha ha
2001-09-12 08:38:13 +00:00

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/*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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 8.15 (Berkeley) 6/16/95
* $FreeBSD$
*/
#include "opt_ffs_broken_fixme.h"
#include "opt_ufs.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/namei.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/proc.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/sysctl.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <ufs/ufs/extattr.h>
#include <ufs/ufs/quota.h>
#include <ufs/ufs/inode.h>
#include <ufs/ufs/dir.h>
#ifdef UFS_DIRHASH
#include <ufs/ufs/dirhash.h>
#endif
#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/ufs_extern.h>
#ifdef DIAGNOSTIC
int dirchk = 1;
#else
int dirchk = 0;
#endif
SYSCTL_INT(_debug, OID_AUTO, dircheck, CTLFLAG_RW, &dirchk, 0, "");
/* true if old FS format...*/
#define OFSFMT(vp) ((vp)->v_mount->mnt_maxsymlinklen <= 0)
/*
* 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.
*
* This routine is actually used as VOP_CACHEDLOOKUP method, and the
* filesystem employs the generic vfs_cache_lookup() as VOP_LOOKUP
* method.
*
* vfs_cache_lookup() performs the following for us:
* check that it is a directory
* check accessibility of directory
* check for modification attempts on read-only mounts
* if name found in cache
* if at end of path and deleting or creating
* drop it
* else
* return name.
* return VOP_CACHEDLOOKUP()
*
* Overall outline of ufs_lookup:
*
* 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
ufs_lookup(ap)
struct vop_cachedlookup_args /* {
struct vnode *a_dvp;
struct vnode **a_vpp;
struct componentname *a_cnp;
} */ *ap;
{
register struct vnode *vdp; /* vnode for directory being searched */
register struct inode *dp; /* inode for directory being searched */
struct buf *bp; /* a buffer of directory entries */
struct 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 *pdp; /* saved dp during symlink work */
struct vnode *tdp; /* returned by VFS_VGET */
doff_t enduseful; /* pointer past last used dir slot */
u_long bmask; /* block offset mask */
int lockparent; /* 1 => lockparent flag is set */
int wantparent; /* 1 => wantparent or lockparent flag */
int namlen, error;
struct vnode **vpp = ap->a_vpp;
struct componentname *cnp = ap->a_cnp;
struct ucred *cred = cnp->cn_cred;
int flags = cnp->cn_flags;
int nameiop = cnp->cn_nameiop;
struct thread *td = cnp->cn_thread;
bp = NULL;
slotoffset = -1;
cnp->cn_flags &= ~PDIRUNLOCK;
/*
* XXX there was a soft-update diff about this I couldn't merge.
* I think this was the equiv.
*/
*vpp = NULL;
vdp = ap->a_dvp;
dp = VTOI(vdp);
lockparent = flags & LOCKPARENT;
wantparent = flags & (LOCKPARENT|WANTPARENT);
/*
* We now have a segment name to search for, and a directory to search.
*
* 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 = DIRECTSIZ(cnp->cn_namelen);
}
bmask = VFSTOUFS(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
#ifdef UFS_DIRHASH
/*
* Use dirhash for fast operations on large directories. The logic
* to determine whether to hash the directory is contained within
* ufsdirhash_build(); a zero return means that it decided to hash
* this directory and it successfully built up the hash table.
*/
if (ufsdirhash_build(dp) == 0) {
/* Look for a free slot if needed. */
enduseful = dp->i_size;
if (slotstatus != FOUND) {
slotoffset = ufsdirhash_findfree(dp, slotneeded,
&slotsize);
if (slotoffset >= 0) {
slotstatus = COMPACT;
enduseful = ufsdirhash_enduseful(dp);
if (enduseful < 0)
enduseful = dp->i_size;
}
}
/* Look up the component. */
numdirpasses = 1;
entryoffsetinblock = 0; /* silence compiler warning */
switch (ufsdirhash_lookup(dp, cnp->cn_nameptr, cnp->cn_namelen,
&dp->i_offset, &bp, nameiop == DELETE ? &prevoff : NULL)) {
case 0:
ep = (struct direct *)((char *)bp->b_data +
(dp->i_offset & bmask));
goto foundentry;
case ENOENT:
dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ);
goto notfound;
default:
/* Something failed; just do a linear search. */
break;
}
}
#endif /* UFS_DIRHASH */
/*
* 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.
*/
if (nameiop != LOOKUP || dp->i_diroff == 0 ||
dp->i_diroff >= dp->i_size) {
entryoffsetinblock = 0;
dp->i_offset = 0;
numdirpasses = 1;
} else {
dp->i_offset = dp->i_diroff;
if ((entryoffsetinblock = dp->i_offset & bmask) &&
(error = UFS_BLKATOFF(vdp, (off_t)dp->i_offset, NULL, &bp)))
return (error);
numdirpasses = 2;
nchstats.ncs_2passes++;
}
prevoff = dp->i_offset;
endsearch = roundup2(dp->i_size, DIRBLKSIZ);
enduseful = 0;
searchloop:
while (dp->i_offset < endsearch) {
/*
* If necessary, get the next directory block.
*/
if ((dp->i_offset & bmask) == 0) {
if (bp != NULL)
brelse(bp);
error =
UFS_BLKATOFF(vdp, (off_t)dp->i_offset, NULL, &bp);
if (error)
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.
*/
ep = (struct direct *)((char *)bp->b_data + entryoffsetinblock);
if (ep->d_reclen == 0 || ep->d_reclen >
DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1)) ||
(dirchk && ufs_dirbadentry(vdp, ep, entryoffsetinblock))) {
int i;
ufs_dirbad(dp, dp->i_offset, "mangled entry");
i = DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1));
dp->i_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 = ep->d_reclen;
if (ep->d_ino != 0)
size -= DIRSIZ(OFSFMT(vdp), ep);
if (size > 0) {
if (size >= slotneeded) {
slotstatus = FOUND;
slotoffset = dp->i_offset;
slotsize = ep->d_reclen;
} else if (slotstatus == NONE) {
slotfreespace += size;
if (slotoffset == -1)
slotoffset = dp->i_offset;
if (slotfreespace >= slotneeded) {
slotstatus = COMPACT;
slotsize = dp->i_offset +
ep->d_reclen - slotoffset;
}
}
}
}
/*
* Check for a name match.
*/
if (ep->d_ino) {
# if (BYTE_ORDER == LITTLE_ENDIAN)
if (OFSFMT(vdp))
namlen = ep->d_type;
else
namlen = ep->d_namlen;
# else
namlen = ep->d_namlen;
# endif
if (namlen == cnp->cn_namelen &&
(cnp->cn_nameptr[0] == ep->d_name[0]) &&
!bcmp(cnp->cn_nameptr, ep->d_name,
(unsigned)namlen)) {
#ifdef UFS_DIRHASH
foundentry:
#endif
/*
* Save directory entry's inode number and
* reclen in ndp->ni_ufs area, and release
* directory buffer.
*/
if (vdp->v_mount->mnt_maxsymlinklen > 0 &&
ep->d_type == DT_WHT) {
slotstatus = FOUND;
slotoffset = dp->i_offset;
slotsize = ep->d_reclen;
dp->i_reclen = slotsize;
enduseful = dp->i_size;
ap->a_cnp->cn_flags |= ISWHITEOUT;
numdirpasses--;
goto notfound;
}
dp->i_ino = ep->d_ino;
dp->i_reclen = ep->d_reclen;
goto found;
}
}
prevoff = dp->i_offset;
dp->i_offset += ep->d_reclen;
entryoffsetinblock += ep->d_reclen;
if (ep->d_ino)
enduseful = dp->i_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--;
dp->i_offset = 0;
endsearch = dp->i_diroff;
goto searchloop;
}
if (bp != NULL)
brelse(bp);
/*
* 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 &&
(ap->a_cnp->cn_flags & DOWHITEOUT) &&
(ap->a_cnp->cn_flags & ISWHITEOUT))) &&
(flags & ISLASTCN) && dp->i_effnlink != 0) {
/*
* Access for write is interpreted as allowing
* creation of files in the directory.
*/
error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread);
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 dp->i_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 dp->i_offset to
* dp->i_offset + dp->i_count.
*/
if (slotstatus == NONE) {
dp->i_offset = roundup2(dp->i_size, DIRBLKSIZ);
dp->i_count = 0;
enduseful = dp->i_offset;
} else if (nameiop == DELETE) {
dp->i_offset = slotoffset;
if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0)
dp->i_count = 0;
else
dp->i_count = dp->i_offset - prevoff;
} else {
dp->i_offset = slotoffset;
dp->i_count = slotsize;
if (enduseful < slotoffset + slotsize)
enduseful = slotoffset + slotsize;
}
dp->i_endoff = roundup2(enduseful, DIRBLKSIZ);
dp->i_flag |= IN_CHANGE | IN_UPDATE;
/*
* 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.
* The pathname buffer is saved so that the name
* can be obtained later.
*
* NB - if the directory is unlocked, then this
* information cannot be used.
*/
cnp->cn_flags |= SAVENAME;
if (!lockparent) {
VOP_UNLOCK(vdp, 0, td);
cnp->cn_flags |= PDIRUNLOCK;
}
return (EJUSTRETURN);
}
/*
* Insert name into cache (as non-existent) if appropriate.
*/
if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE)
cache_enter(vdp, *vpp, cnp);
return (ENOENT);
found:
if (numdirpasses == 2)
nchstats.ncs_pass2++;
/*
* Check that directory length properly reflects presence
* of this entry.
*/
if (dp->i_offset + DIRSIZ(OFSFMT(vdp), ep) > dp->i_size) {
ufs_dirbad(dp, dp->i_offset, "i_size too small");
dp->i_size = dp->i_offset + DIRSIZ(OFSFMT(vdp), ep);
dp->i_flag |= IN_CHANGE | IN_UPDATE;
}
brelse(bp);
/*
* 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)
dp->i_diroff = dp->i_offset &~ (DIRBLKSIZ - 1);
/*
* If deleting, and at end of pathname, return
* parameters which can be used to remove file.
* If the wantparent flag isn't set, we return only
* the directory (in ndp->ni_dvp), otherwise we go
* on and lock the inode, being careful with ".".
*/
if (nameiop == DELETE && (flags & ISLASTCN)) {
/*
* Write access to directory required to delete files.
*/
error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread);
if (error)
return (error);
/*
* Return pointer to current entry in dp->i_offset,
* and distance past previous entry (if there
* is a previous entry in this block) in dp->i_count.
* Save directory inode pointer in ndp->ni_dvp for dirremove().
*/
if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0)
dp->i_count = 0;
else
dp->i_count = dp->i_offset - prevoff;
if (dp->i_number == dp->i_ino) {
VREF(vdp);
*vpp = vdp;
return (0);
}
if (flags & ISDOTDOT)
VOP_UNLOCK(vdp, 0, td); /* race to get the inode */
error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp);
if (flags & ISDOTDOT) {
if (vn_lock(vdp, LK_EXCLUSIVE | LK_RETRY, td) != 0)
cnp->cn_flags |= PDIRUNLOCK;
}
if (error)
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_mode & ISVTX) &&
VOP_ACCESS(vdp, VADMIN, cred, cnp->cn_thread) &&
VOP_ACCESS(tdp, VADMIN, cred, cnp->cn_thread)) {
vput(tdp);
return (EPERM);
}
*vpp = tdp;
if (!lockparent) {
VOP_UNLOCK(vdp, 0, td);
cnp->cn_flags |= PDIRUNLOCK;
}
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 && wantparent && (flags & ISLASTCN)) {
if ((error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread)) != 0)
return (error);
/*
* Careful about locking second inode.
* This can only occur if the target is ".".
*/
if (dp->i_number == dp->i_ino)
return (EISDIR);
if (flags & ISDOTDOT)
VOP_UNLOCK(vdp, 0, td); /* race to get the inode */
error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp);
if (flags & ISDOTDOT) {
if (vn_lock(vdp, LK_EXCLUSIVE | LK_RETRY, td) != 0)
cnp->cn_flags |= PDIRUNLOCK;
}
if (error)
return (error);
*vpp = tdp;
cnp->cn_flags |= SAVENAME;
if (!lockparent) {
VOP_UNLOCK(vdp, 0, td);
cnp->cn_flags |= PDIRUNLOCK;
}
return (0);
}
/*
* Step through the translation in the name. We do not `vput' the
* directory because we may need it again if a symbolic link
* is relative to the current directory. Instead we save it
* unlocked as "pdp". We must get the target inode before unlocking
* the directory to insure that the inode will not be removed
* before we get it. We prevent deadlock by always fetching
* inodes from the root, moving down the directory tree. Thus
* when following backward pointers ".." we must unlock the
* parent directory before getting the requested directory.
* There is a potential race condition here if both the current
* and parent directories are removed before the VFS_VGET for the
* inode associated with ".." returns. We hope that this occurs
* infrequently since we cannot avoid this race condition without
* implementing a sophisticated deadlock detection algorithm.
* Note also that this simple deadlock detection scheme will not
* work if the file system has any hard links other than ".."
* that point backwards in the directory structure.
*/
pdp = vdp;
if (flags & ISDOTDOT) {
VOP_UNLOCK(pdp, 0, td); /* race to get the inode */
cnp->cn_flags |= PDIRUNLOCK;
if ((error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp)) != 0) {
if (vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY, td) == 0)
cnp->cn_flags &= ~PDIRUNLOCK;
return (error);
}
if (lockparent && (flags & ISLASTCN)) {
if ((error = vn_lock(pdp, LK_EXCLUSIVE, td)) != 0) {
vput(tdp);
return (error);
}
cnp->cn_flags &= ~PDIRUNLOCK;
}
*vpp = tdp;
} else if (dp->i_number == dp->i_ino) {
VREF(vdp); /* we want ourself, ie "." */
*vpp = vdp;
} else {
error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp);
if (error)
return (error);
if (!lockparent || !(flags & ISLASTCN)) {
VOP_UNLOCK(pdp, 0, td);
cnp->cn_flags |= PDIRUNLOCK;
}
*vpp = tdp;
}
/*
* Insert name into cache if appropriate.
*/
if (cnp->cn_flags & MAKEENTRY)
cache_enter(vdp, *vpp, cnp);
return (0);
}
void
ufs_dirbad(ip, offset, how)
struct inode *ip;
doff_t offset;
char *how;
{
struct mount *mp;
mp = ITOV(ip)->v_mount;
(void)printf("%s: bad dir ino %lu at offset %ld: %s\n",
mp->mnt_stat.f_mntonname, (u_long)ip->i_number, (long)offset, how);
if ((mp->mnt_flag & MNT_RDONLY) == 0)
panic("ufs_dirbad: 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 MAXNAMLEN
* name must be as long as advertised, and null terminated
*/
int
ufs_dirbadentry(dp, ep, entryoffsetinblock)
struct vnode *dp;
register struct direct *ep;
int entryoffsetinblock;
{
register int i;
int namlen;
# if (BYTE_ORDER == LITTLE_ENDIAN)
if (OFSFMT(dp))
namlen = ep->d_type;
else
namlen = ep->d_namlen;
# else
namlen = ep->d_namlen;
# endif
if ((ep->d_reclen & 0x3) != 0 ||
ep->d_reclen > DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1)) ||
ep->d_reclen < DIRSIZ(OFSFMT(dp), ep) || namlen > MAXNAMLEN) {
/*return (1); */
printf("First bad\n");
goto bad;
}
if (ep->d_ino == 0)
return (0);
for (i = 0; i < namlen; i++)
if (ep->d_name[i] == '\0') {
/*return (1); */
printf("Second bad\n");
goto bad;
}
if (ep->d_name[i])
goto bad;
return (0);
bad:
return (1);
}
/*
* Construct a new directory entry after a call to namei, using the
* parameters that it left in the componentname argument cnp. The
* argument ip is the inode to which the new directory entry will refer.
*/
void
ufs_makedirentry(ip, cnp, newdirp)
struct inode *ip;
struct componentname *cnp;
struct direct *newdirp;
{
#ifdef DIAGNOSTIC
if ((cnp->cn_flags & SAVENAME) == 0)
panic("ufs_makedirentry: missing name");
#endif
newdirp->d_ino = ip->i_number;
newdirp->d_namlen = cnp->cn_namelen;
bcopy(cnp->cn_nameptr, newdirp->d_name, (unsigned)cnp->cn_namelen + 1);
if (ITOV(ip)->v_mount->mnt_maxsymlinklen > 0)
newdirp->d_type = IFTODT(ip->i_mode);
else {
newdirp->d_type = 0;
# if (BYTE_ORDER == LITTLE_ENDIAN)
{ u_char tmp = newdirp->d_namlen;
newdirp->d_namlen = newdirp->d_type;
newdirp->d_type = tmp; }
# endif
}
}
/*
* Write a directory entry after a call to namei, using the parameters
* that it left in nameidata. The argument dirp is the new directory
* entry contents. Dvp is a pointer to the directory to be written,
* which was left locked by namei. Remaining parameters (dp->i_offset,
* dp->i_count) indicate how the space for the new entry is to be obtained.
* Non-null bp indicates that a directory is being created (for the
* soft dependency code).
*/
int
ufs_direnter(dvp, tvp, dirp, cnp, newdirbp)
struct vnode *dvp;
struct vnode *tvp;
struct direct *dirp;
struct componentname *cnp;
struct buf *newdirbp;
{
struct ucred *cr;
struct thread *td;
int newentrysize;
struct inode *dp;
struct buf *bp;
u_int dsize;
struct direct *ep, *nep;
int error, ret, blkoff, loc, spacefree, flags;
char *dirbuf;
td = curthread; /* XXX */
cr = td->td_proc->p_ucred;
dp = VTOI(dvp);
newentrysize = DIRSIZ(OFSFMT(dvp), dirp);
if (dp->i_count == 0) {
/*
* If dp->i_count is 0, then namei could find no
* space in the directory. Here, dp->i_offset will
* be on a directory block boundary and we will write the
* new entry into a fresh block.
*/
if (dp->i_offset & (DIRBLKSIZ - 1))
panic("ufs_direnter: newblk");
flags = B_CLRBUF;
if (!DOINGSOFTDEP(dvp) && !DOINGASYNC(dvp))
flags |= B_SYNC;
if ((error = UFS_BALLOC(dvp, (off_t)dp->i_offset, DIRBLKSIZ,
cr, flags, &bp)) != 0) {
if (DOINGSOFTDEP(dvp) && newdirbp != NULL)
bdwrite(newdirbp);
return (error);
}
dp->i_size = dp->i_offset + DIRBLKSIZ;
dp->i_flag |= IN_CHANGE | IN_UPDATE;
vnode_pager_setsize(dvp, (u_long)dp->i_size);
dirp->d_reclen = DIRBLKSIZ;
blkoff = dp->i_offset &
(VFSTOUFS(dvp->v_mount)->um_mountp->mnt_stat.f_iosize - 1);
bcopy((caddr_t)dirp, (caddr_t)bp->b_data + blkoff,newentrysize);
#ifdef UFS_DIRHASH
if (dp->i_dirhash != NULL) {
ufsdirhash_newblk(dp, dp->i_offset);
ufsdirhash_add(dp, dirp, dp->i_offset);
ufsdirhash_checkblock(dp, (char *)bp->b_data + blkoff,
dp->i_offset);
}
#endif
if (DOINGSOFTDEP(dvp)) {
/*
* Ensure that the entire newly allocated block is a
* valid directory so that future growth within the
* block does not have to ensure that the block is
* written before the inode.
*/
blkoff += DIRBLKSIZ;
while (blkoff < bp->b_bcount) {
((struct direct *)
(bp->b_data + blkoff))->d_reclen = DIRBLKSIZ;
blkoff += DIRBLKSIZ;
}
if (softdep_setup_directory_add(bp, dp, dp->i_offset,
dirp->d_ino, newdirbp, 1) == 0) {
bdwrite(bp);
return (UFS_UPDATE(dvp, 0));
}
/* We have just allocated a directory block in an
* indirect block. Rather than tracking when it gets
* claimed by the inode, we simply do a VOP_FSYNC
* now to ensure that it is there (in case the user
* does a future fsync). Note that we have to unlock
* the inode for the entry that we just entered, as
* the VOP_FSYNC may need to lock other inodes which
* can lead to deadlock if we also hold a lock on
* the newly entered node.
*/
if ((error = BUF_WRITE(bp)))
return (error);
if (tvp != NULL)
VOP_UNLOCK(tvp, 0, td);
error = VOP_FSYNC(dvp, td->td_proc->p_ucred, MNT_WAIT, td);
if (tvp != NULL)
vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY, td);
return (error);
}
if (DOINGASYNC(dvp)) {
bdwrite(bp);
return (UFS_UPDATE(dvp, 0));
}
error = BUF_WRITE(bp);
ret = UFS_UPDATE(dvp, 1);
if (error == 0)
return (ret);
return (error);
}
/*
* If dp->i_count is non-zero, then namei found space for the new
* entry in the range dp->i_offset to dp->i_offset + dp->i_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
* DIRBLKSIZE.
*
* N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN.
*/
if (dp->i_offset + dp->i_count > dp->i_size)
dp->i_size = dp->i_offset + dp->i_count;
/*
* Get the block containing the space for the new directory entry.
*/
error = UFS_BLKATOFF(dvp, (off_t)dp->i_offset, &dirbuf, &bp);
if (error) {
if (DOINGSOFTDEP(dvp) && newdirbp != NULL)
bdwrite(newdirbp);
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 dp->i_offset to
* dp->i_offset + dp->i_count would yield the space.
*/
ep = (struct direct *)dirbuf;
dsize = ep->d_ino ? DIRSIZ(OFSFMT(dvp), ep) : 0;
spacefree = ep->d_reclen - dsize;
for (loc = ep->d_reclen; loc < dp->i_count; ) {
nep = (struct direct *)(dirbuf + loc);
/* Trim the existing slot (NB: dsize may be zero). */
ep->d_reclen = dsize;
ep = (struct direct *)((char *)ep + dsize);
/* Read nep->d_reclen now as the bcopy() may clobber it. */
loc += nep->d_reclen;
if (nep->d_ino == 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 bcopy it.
*/
spacefree += nep->d_reclen;
ep->d_ino = 0;
dsize = 0;
continue;
}
dsize = DIRSIZ(OFSFMT(dvp), nep);
spacefree += nep->d_reclen - dsize;
#ifdef UFS_DIRHASH
if (dp->i_dirhash != NULL)
ufsdirhash_move(dp, nep,
dp->i_offset + ((char *)nep - dirbuf),
dp->i_offset + ((char *)ep - dirbuf));
#endif
if (DOINGSOFTDEP(dvp))
softdep_change_directoryentry_offset(dp, dirbuf,
(caddr_t)nep, (caddr_t)ep, dsize);
else
bcopy((caddr_t)nep, (caddr_t)ep, 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 (ep->d_ino == 0 ||
(ep->d_ino == WINO &&
bcmp(ep->d_name, dirp->d_name, dirp->d_namlen) == 0)) {
if (spacefree + dsize < newentrysize)
panic("ufs_direnter: compact1");
dirp->d_reclen = spacefree + dsize;
} else {
if (spacefree < newentrysize)
panic("ufs_direnter: compact2");
dirp->d_reclen = spacefree;
ep->d_reclen = dsize;
ep = (struct direct *)((char *)ep + dsize);
}
#ifdef UFS_DIRHASH
if (dp->i_dirhash != NULL && (ep->d_ino == 0 ||
dirp->d_reclen == spacefree))
ufsdirhash_add(dp, dirp, dp->i_offset + ((char *)ep - dirbuf));
#endif
bcopy((caddr_t)dirp, (caddr_t)ep, (u_int)newentrysize);
#ifdef UFS_DIRHASH
if (dp->i_dirhash != NULL)
ufsdirhash_checkblock(dp, dirbuf -
(dp->i_offset & (DIRBLKSIZ - 1)),
dp->i_offset & ~(DIRBLKSIZ - 1));
#endif
if (DOINGSOFTDEP(dvp)) {
(void) softdep_setup_directory_add(bp, dp,
dp->i_offset + (caddr_t)ep - dirbuf,
dirp->d_ino, newdirbp, 0);
bdwrite(bp);
} else {
if (DOINGASYNC(dvp)) {
bdwrite(bp);
error = 0;
} else {
error = bowrite(bp);
}
}
dp->i_flag |= 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 && dp->i_endoff && dp->i_endoff < dp->i_size) {
if (tvp != NULL)
VOP_UNLOCK(tvp, 0, td);
#ifdef UFS_DIRHASH
if (dp->i_dirhash != NULL)
ufsdirhash_dirtrunc(dp, dp->i_endoff);
#endif
(void) UFS_TRUNCATE(dvp, (off_t)dp->i_endoff, IO_SYNC, cr, td);
if (tvp != NULL)
vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY, td);
}
return (error);
}
/*
* Remove a directory entry after a call to namei, using
* the parameters which it left in nameidata. The entry
* dp->i_offset contains the offset into the directory of the
* entry to be eliminated. The dp->i_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
ufs_dirremove(dvp, ip, flags, isrmdir)
struct vnode *dvp;
struct inode *ip;
int flags;
int isrmdir;
{
struct inode *dp;
struct direct *ep;
struct buf *bp;
int error;
dp = VTOI(dvp);
if (flags & DOWHITEOUT) {
/*
* Whiteout entry: set d_ino to WINO.
*/
if ((error =
UFS_BLKATOFF(dvp, (off_t)dp->i_offset, (char **)&ep, &bp)) != 0)
return (error);
ep->d_ino = WINO;
ep->d_type = DT_WHT;
goto out;
}
if ((error = UFS_BLKATOFF(dvp,
(off_t)(dp->i_offset - dp->i_count), (char **)&ep, &bp)) != 0)
return (error);
#ifdef UFS_DIRHASH
/*
* Remove the dirhash entry. This is complicated by the fact
* that `ep' is the previous entry when dp->i_count != 0.
*/
if (dp->i_dirhash != NULL)
ufsdirhash_remove(dp, (dp->i_count == 0) ? ep :
(struct direct *)((char *)ep + ep->d_reclen), dp->i_offset);
#endif
if (dp->i_count == 0) {
/*
* First entry in block: set d_ino to zero.
*/
ep->d_ino = 0;
} else {
/*
* Collapse new free space into previous entry.
*/
ep->d_reclen += dp->i_reclen;
}
#ifdef UFS_DIRHASH
if (dp->i_dirhash != NULL)
ufsdirhash_checkblock(dp, (char *)ep -
((dp->i_offset - dp->i_count) & (DIRBLKSIZ - 1)),
dp->i_offset & ~(DIRBLKSIZ - 1));
#endif
out:
if (DOINGSOFTDEP(dvp)) {
if (ip) {
ip->i_effnlink--;
softdep_change_linkcnt(ip);
softdep_setup_remove(bp, dp, ip, isrmdir);
}
if (softdep_slowdown(dvp)) {
error = BUF_WRITE(bp);
} else {
bdwrite(bp);
error = 0;
}
} else {
if (ip) {
ip->i_effnlink--;
ip->i_nlink--;
ip->i_flag |= IN_CHANGE;
}
if (flags & DOWHITEOUT)
error = BUF_WRITE(bp);
else if (DOINGASYNC(dvp) && dp->i_count != 0) {
bdwrite(bp);
error = 0;
} else
error = bowrite(bp);
}
dp->i_flag |= 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 defined(FFS) || defined(IFS)
if (ip != 0 && (ip->i_flags & SF_SNAPSHOT) != 0 && ip->i_effnlink == 0)
ffs_snapgone(ip);
#endif
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
ufs_dirrewrite(dp, oip, newinum, newtype, isrmdir)
struct inode *dp, *oip;
ino_t newinum;
int newtype;
int isrmdir;
{
struct buf *bp;
struct direct *ep;
struct vnode *vdp = ITOV(dp);
int error;
error = UFS_BLKATOFF(vdp, (off_t)dp->i_offset, (char **)&ep, &bp);
if (error)
return (error);
ep->d_ino = newinum;
if (!OFSFMT(vdp))
ep->d_type = newtype;
oip->i_effnlink--;
if (DOINGSOFTDEP(vdp)) {
softdep_change_linkcnt(oip);
softdep_setup_directory_change(bp, dp, oip, newinum, isrmdir);
bdwrite(bp);
} else {
oip->i_nlink--;
oip->i_flag |= IN_CHANGE;
if (DOINGASYNC(vdp)) {
bdwrite(bp);
error = 0;
} else {
error = bowrite(bp);
}
}
dp->i_flag |= 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 defined(FFS) || defined(IFS)
if ((oip->i_flags & SF_SNAPSHOT) != 0 && oip->i_effnlink == 0)
ffs_snapgone(oip);
#endif
return (error);
}
/*
* Check if a directory is empty or not.
* Inode supplied must be locked.
*
* Using a struct dirtemplate here is not precisely
* what we want, but better than using a struct direct.
*
* NB: does not handle corrupted directories.
*/
int
ufs_dirempty(ip, parentino, cred)
register struct inode *ip;
ino_t parentino;
struct ucred *cred;
{
register off_t off;
struct dirtemplate dbuf;
register struct direct *dp = (struct direct *)&dbuf;
int error, count, namlen;
#define MINDIRSIZ (sizeof (struct dirtemplate) / 2)
for (off = 0; off < ip->i_size; off += dp->d_reclen) {
error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ, off,
UIO_SYSSPACE, IO_NODELOCKED, cred, &count, (struct thread *)0);
/*
* 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 (dp->d_reclen == 0)
return (0);
/* skip empty entries */
if (dp->d_ino == 0 || dp->d_ino == WINO)
continue;
/* accept only "." and ".." */
# if (BYTE_ORDER == LITTLE_ENDIAN)
if (OFSFMT(ITOV(ip)))
namlen = dp->d_type;
else
namlen = dp->d_namlen;
# else
namlen = dp->d_namlen;
# endif
if (namlen > 2)
return (0);
if (dp->d_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 && dp->d_ino == ip->i_number)
continue;
if (dp->d_name[1] == '.' && dp->d_ino == parentino)
continue;
return (0);
}
return (1);
}
/*
* Check if source directory is in the path of the target directory.
* Target is supplied locked, source is unlocked.
* The target is always vput before returning.
*/
int
ufs_checkpath(source, target, cred)
struct inode *source, *target;
struct ucred *cred;
{
struct vnode *vp;
int error, rootino, namlen;
struct dirtemplate dirbuf;
vp = ITOV(target);
if (target->i_number == source->i_number) {
error = EEXIST;
goto out;
}
rootino = ROOTINO;
error = 0;
if (target->i_number == rootino)
goto out;
for (;;) {
if (vp->v_type != VDIR) {
error = ENOTDIR;
break;
}
error = vn_rdwr(UIO_READ, vp, (caddr_t)&dirbuf,
sizeof (struct dirtemplate), (off_t)0, UIO_SYSSPACE,
IO_NODELOCKED, cred, (int *)0, (struct thread *)0);
if (error != 0)
break;
# if (BYTE_ORDER == LITTLE_ENDIAN)
if (OFSFMT(vp))
namlen = dirbuf.dotdot_type;
else
namlen = dirbuf.dotdot_namlen;
# else
namlen = dirbuf.dotdot_namlen;
# endif
if (namlen != 2 ||
dirbuf.dotdot_name[0] != '.' ||
dirbuf.dotdot_name[1] != '.') {
error = ENOTDIR;
break;
}
if (dirbuf.dotdot_ino == source->i_number) {
error = EINVAL;
break;
}
if (dirbuf.dotdot_ino == rootino)
break;
vput(vp);
error = VFS_VGET(vp->v_mount, dirbuf.dotdot_ino, &vp);
if (error) {
vp = NULL;
break;
}
}
out:
if (error == ENOTDIR)
printf("checkpath: .. not a directory\n");
if (vp != NULL)
vput(vp);
return (error);
}
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