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freebsd-skq/sys/ufs/ufs/ufs_lookup.c
jeff a574495410 - Merge soft-updates journaling from projects/suj/head into head. This 
brings in support for an optional intent log which eliminates the need
   for background fsck on unclean shutdown.

Sponsored by:   iXsystems, Yahoo!, and Juniper.
With help from: McKusick and Peter Holm
2010-04-24 07:05:35 +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.
* 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
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ffs_broken_fixme.h"
#include "opt_ufs.h"
#include "opt_quota.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
static int dirchk = 1;
#else
static 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)
static int
ufs_delete_denied(struct vnode *vdp, struct vnode *tdp, struct ucred *cred,
struct thread *td)
{
int error;
#ifdef UFS_ACL
/*
* NFSv4 Minor Version 1, draft-ietf-nfsv4-minorversion1-03.txt
*
* 3.16.2.1. ACE4_DELETE vs. ACE4_DELETE_CHILD
*/
/*
* XXX: Is this check required?
*/
error = VOP_ACCESS(vdp, VEXEC, cred, td);
if (error)
return (error);
error = VOP_ACCESSX(tdp, VDELETE, cred, td);
if (error == 0)
return (0);
error = VOP_ACCESSX(vdp, VDELETE_CHILD, cred, td);
if (error == 0)
return (0);
error = VOP_ACCESSX(vdp, VEXPLICIT_DENY | VDELETE_CHILD, cred, td);
if (error)
return (error);
#endif /* !UFS_ACL */
/*
* Standard Unix access control - delete access requires VWRITE.
*/
error = VOP_ACCESS(vdp, VWRITE, cred, td);
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 ((VTOI(vdp)->i_mode & ISVTX) &&
VOP_ACCESS(vdp, VADMIN, cred, td) &&
VOP_ACCESS(tdp, VADMIN, cred, td))
return (EPERM);
return (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 filesystem 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;
{
return (ufs_lookup_ino(ap->a_dvp, ap->a_vpp, ap->a_cnp, NULL));
}
int
ufs_lookup_ino(struct vnode *vdp, struct vnode **vpp, struct componentname *cnp,
ino_t *dd_ino)
{
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 */
doff_t i_diroff; /* cached i_diroff value. */
doff_t i_offset; /* cached i_offset value. */
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 namlen, error;
struct ucred *cred = cnp->cn_cred;
int flags = cnp->cn_flags;
int nameiop = cnp->cn_nameiop;
ino_t ino, ino1;
int ltype;
if (vpp != NULL)
*vpp = NULL;
dp = VTOI(vdp);
/*
* Create a vm object if vmiodirenable is enabled.
* Alternatively we could call vnode_create_vobject
* in VFS_VGET but we could end up creating objects
* that are never used.
*/
vnode_create_vobject(vdp, DIP(dp, i_size), cnp->cn_thread);
bmask = VFSTOUFS(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
restart:
bp = NULL;
slotoffset = -1;
/*
* 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.
*/
ino = 0;
i_diroff = dp->i_diroff;
slotstatus = FOUND;
slotfreespace = slotsize = slotneeded = 0;
if ((nameiop == CREATE || nameiop == RENAME) &&
(flags & ISLASTCN)) {
slotstatus = NONE;
slotneeded = DIRECTSIZ(cnp->cn_namelen);
}
#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,
&i_offset, &bp, nameiop == DELETE ? &prevoff : NULL)) {
case 0:
ep = (struct direct *)((char *)bp->b_data +
(i_offset & bmask));
goto foundentry;
case ENOENT:
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 || i_diroff == 0 || i_diroff >= dp->i_size) {
entryoffsetinblock = 0;
i_offset = 0;
numdirpasses = 1;
} else {
i_offset = i_diroff;
if ((entryoffsetinblock = i_offset & bmask) &&
(error = UFS_BLKATOFF(vdp, (off_t)i_offset, NULL, &bp)))
return (error);
numdirpasses = 2;
nchstats.ncs_2passes++;
}
prevoff = i_offset;
endsearch = roundup2(dp->i_size, DIRBLKSIZ);
enduseful = 0;
searchloop:
while (i_offset < endsearch) {
/*
* If necessary, get the next directory block.
*/
if ((i_offset & bmask) == 0) {
if (bp != NULL)
brelse(bp);
error =
UFS_BLKATOFF(vdp, (off_t)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, i_offset, "mangled entry");
i = DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1));
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 = i_offset;
slotsize = ep->d_reclen;
} else if (slotstatus == NONE) {
slotfreespace += size;
if (slotoffset == -1)
slotoffset = i_offset;
if (slotfreespace >= slotneeded) {
slotstatus = COMPACT;
slotsize = 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 = i_offset;
slotsize = ep->d_reclen;
enduseful = dp->i_size;
cnp->cn_flags |= ISWHITEOUT;
numdirpasses--;
goto notfound;
}
ino = ep->d_ino;
goto found;
}
}
prevoff = i_offset;
i_offset += ep->d_reclen;
entryoffsetinblock += ep->d_reclen;
if (ep->d_ino)
enduseful = 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--;
i_offset = 0;
endsearch = 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 &&
(cnp->cn_flags & DOWHITEOUT) &&
(cnp->cn_flags & ISWHITEOUT))) &&
(flags & ISLASTCN) && dp->i_effnlink != 0) {
/*
* Access for write is interpreted as allowing
* creation of files in the directory.
*
* XXX: Fix the comment above.
*/
if (flags & WILLBEDIR)
error = VOP_ACCESSX(vdp, VWRITE | VAPPEND, cred, cnp->cn_thread);
else
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);
/*
* 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;
return (EJUSTRETURN);
}
/*
* Insert name into cache (as non-existent) if appropriate.
*/
if ((cnp->cn_flags & MAKEENTRY) && nameiop != CREATE)
cache_enter(vdp, NULL, cnp);
return (ENOENT);
found:
if (dd_ino != NULL)
*dd_ino = ino;
if (numdirpasses == 2)
nchstats.ncs_pass2++;
/*
* Check that directory length properly reflects presence
* of this entry.
*/
if (i_offset + DIRSIZ(OFSFMT(vdp), ep) > dp->i_size) {
ufs_dirbad(dp, i_offset, "i_size too small");
dp->i_size = i_offset + DIRSIZ(OFSFMT(vdp), ep);
DIP_SET(dp, i_size, dp->i_size);
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 = i_offset &~ (DIRBLKSIZ - 1);
/*
* If deleting, and at end of pathname, return
* parameters which can be used to remove file.
*/
if (nameiop == DELETE && (flags & ISLASTCN)) {
if (flags & LOCKPARENT)
ASSERT_VOP_ELOCKED(vdp, __FUNCTION__);
/*
* 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().
*
* Technically we shouldn't be setting these in the
* WANTPARENT case (first lookup in rename()), but any
* lookups that will result in directory changes will
* overwrite these.
*/
dp->i_offset = i_offset;
if ((dp->i_offset & (DIRBLKSIZ - 1)) == 0)
dp->i_count = 0;
else
dp->i_count = dp->i_offset - prevoff;
if (dd_ino != NULL)
return (0);
if ((error = VFS_VGET(vdp->v_mount, ino,
LK_EXCLUSIVE, &tdp)) != 0)
return (error);
error = ufs_delete_denied(vdp, tdp, cred, cnp->cn_thread);
if (error) {
vput(tdp);
return (error);
}
if (dp->i_number == ino) {
VREF(vdp);
*vpp = vdp;
vput(tdp);
return (0);
}
*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)) {
if (flags & WILLBEDIR)
error = VOP_ACCESSX(vdp, VWRITE | VAPPEND, cred, cnp->cn_thread);
else
error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread);
if (error)
return (error);
/*
* Careful about locking second inode.
* This can only occur if the target is ".".
*/
dp->i_offset = i_offset;
if (dp->i_number == ino)
return (EISDIR);
if (dd_ino != NULL)
return (0);
if ((error = VFS_VGET(vdp->v_mount, ino,
LK_EXCLUSIVE, &tdp)) != 0)
return (error);
error = ufs_delete_denied(vdp, tdp, cred, cnp->cn_thread);
if (error) {
vput(tdp);
return (error);
}
#ifdef SunOS_doesnt_do_that
/*
* The only purpose of this check is to return the correct
* error. Assume that we want to rename directory "a"
* to a file "b", and that we have no ACL_WRITE_DATA on
* a containing directory, but we _do_ have ACL_APPEND_DATA.
* In that case, the VOP_ACCESS check above will return 0,
* and the operation will fail with ENOTDIR instead
* of EACCESS.
*/
if (tdp->v_type == VDIR)
error = VOP_ACCESSX(vdp, VWRITE | VAPPEND, cred, cnp->cn_thread);
else
error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_thread);
if (error) {
vput(tdp);
return (error);
}
#endif
*vpp = tdp;
cnp->cn_flags |= SAVENAME;
return (0);
}
if (dd_ino != NULL)
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 filesystem has any hard links other than ".."
* that point backwards in the directory structure.
*/
pdp = vdp;
if (flags & ISDOTDOT) {
error = vn_vget_ino(pdp, ino, cnp->cn_lkflags, &tdp);
if (error)
return (error);
/*
* Recheck that ".." entry in the vdp directory points
* to the inode we looked up before vdp lock was
* dropped.
*/
error = ufs_lookup_ino(pdp, NULL, cnp, &ino1);
if (error) {
vput(tdp);
return (error);
}
if (ino1 != ino) {
vput(tdp);
goto restart;
}
*vpp = tdp;
} else if (dp->i_number == ino) {
VREF(vdp); /* we want ourself, ie "." */
/*
* When we lookup "." we still can be asked to lock it
* differently.
*/
ltype = cnp->cn_lkflags & LK_TYPE_MASK;
if (ltype != VOP_ISLOCKED(vdp)) {
if (ltype == LK_EXCLUSIVE)
vn_lock(vdp, LK_UPGRADE | LK_RETRY);
else /* if (ltype == LK_SHARED) */
vn_lock(vdp, LK_DOWNGRADE | LK_RETRY);
/*
* Relock for the "." case may left us with
* reclaimed vnode.
*/
if (vdp->v_iflag & VI_DOOMED) {
vrele(vdp);
return (ENOENT);
}
}
*vpp = vdp;
} else {
error = VFS_VGET(pdp->v_mount, ino, cnp->cn_lkflags, &tdp);
if (error)
return (error);
*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;
if ((mp->mnt_flag & MNT_RDONLY) == 0)
panic("ufs_dirbad: %s: bad dir ino %lu at offset %ld: %s",
mp->mnt_stat.f_mntonname, (u_long)ip->i_number, (long)offset, how);
else
(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);
}
/*
* 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;
struct direct *ep;
int entryoffsetinblock;
{
int i, 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 INVARIANTS
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, isrename)
struct vnode *dvp;
struct vnode *tvp;
struct direct *dirp;
struct componentname *cnp;
struct buf *newdirbp;
int isrename;
{
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, namlen;
char *dirbuf;
td = curthread; /* XXX */
cr = td->td_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 = BA_CLRBUF;
if (!DOINGSOFTDEP(dvp) && !DOINGASYNC(dvp))
flags |= IO_SYNC;
#ifdef QUOTA
if ((error = getinoquota(dp)) != 0) {
if (DOINGSOFTDEP(dvp) && newdirbp != NULL)
bdwrite(newdirbp);
return (error);
}
#endif
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;
DIP_SET(dp, i_size, dp->i_size);
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))
dp->i_flag |= IN_NEEDSYNC;
if (newdirbp)
bdwrite(newdirbp);
bdwrite(bp);
if ((dp->i_flag & IN_NEEDSYNC) == 0)
return (UFS_UPDATE(dvp, 0));
/*
* We have just allocated a directory block in an
* indirect block. We must prevent holes in the
* directory created if directory entries are
* written out of order. To accomplish this we
* fsync when we extend a directory into indirects.
* During rename it's not safe to drop the tvp lock
* so sync must be delayed until it is.
*
* This synchronous step could be removed if fsck and
* the kernel were taught to fill in sparse
* directories rather than panic.
*/
if (isrename)
return (0);
if (tvp != NULL)
VOP_UNLOCK(tvp, 0);
error = VOP_FSYNC(dvp, MNT_WAIT, td);
if (tvp != NULL)
vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY);
return (error);
}
if (DOINGASYNC(dvp)) {
bdwrite(bp);
return (UFS_UPDATE(dvp, 0));
}
error = bwrite(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;
DIP_SET(dp, i_size, dp->i_size);
}
/*
* 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(bp, 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 (BYTE_ORDER == LITTLE_ENDIAN)
if (OFSFMT(dvp))
namlen = ep->d_type;
else
namlen = ep->d_namlen;
# else
namlen = ep->d_namlen;
# endif
if (ep->d_ino == 0 ||
(ep->d_ino == WINO && namlen == dirp->d_namlen &&
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);
if (newdirbp != NULL)
bdwrite(newdirbp);
bdwrite(bp);
} else {
if (DOINGASYNC(dvp)) {
bdwrite(bp);
error = 0;
} else {
error = bwrite(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 (isrename == 0 && error == 0 &&
dp->i_endoff && dp->i_endoff < dp->i_size) {
if (tvp != NULL)
VOP_UNLOCK(tvp, 0);
#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_NORMAL | IO_SYNC, cr, td);
if (tvp != NULL)
vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY);
}
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, *rep;
struct buf *bp;
int error;
dp = VTOI(dvp);
/*
* Adjust the link count early so softdep can block if necessary.
*/
if (ip) {
ip->i_effnlink--;
if (DOINGSOFTDEP(dvp)) {
softdep_setup_unlink(dp, ip);
} else {
ip->i_nlink--;
DIP_SET(ip, i_nlink, ip->i_nlink);
ip->i_flag |= IN_CHANGE;
}
}
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);
/* Set 'rep' to the entry being removed. */
if (dp->i_count == 0)
rep = ep;
else
rep = (struct direct *)((char *)ep + ep->d_reclen);
#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, rep, dp->i_offset);
#endif
if (ip && rep->d_ino != ip->i_number)
panic("ufs_dirremove: ip %d does not match dirent ino %d\n",
ip->i_number, rep->d_ino);
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 += rep->d_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:
error = 0;
if (DOINGSOFTDEP(dvp)) {
if (ip)
softdep_setup_remove(bp, dp, ip, isrmdir);
if (softdep_slowdown(dvp))
error = bwrite(bp);
else
bdwrite(bp);
} else {
if (flags & DOWHITEOUT)
error = bwrite(bp);
else if (DOINGASYNC(dvp) && dp->i_count != 0)
bdwrite(bp);
else
error = bwrite(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;
/*
* Drop the link before we lock the buf so softdep can block if
* necessary.
*/
oip->i_effnlink--;
if (DOINGSOFTDEP(vdp)) {
softdep_setup_unlink(dp, oip);
} else {
oip->i_nlink--;
DIP_SET(oip, i_nlink, oip->i_nlink);
oip->i_flag |= IN_CHANGE;
}
error = UFS_BLKATOFF(vdp, (off_t)dp->i_offset, (char **)&ep, &bp);
if (error)
return (error);
if (ep->d_namlen == 2 && ep->d_name[1] == '.' && ep->d_name[0] == '.' &&
ep->d_ino != oip->i_number) {
brelse(bp);
return (EIDRM);
}
ep->d_ino = newinum;
if (!OFSFMT(vdp))
ep->d_type = newtype;
if (DOINGSOFTDEP(vdp)) {
softdep_setup_directory_change(bp, dp, oip, newinum, isrmdir);
bdwrite(bp);
} else {
if (DOINGASYNC(vdp)) {
bdwrite(bp);
error = 0;
} else {
error = bwrite(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)
struct inode *ip;
ino_t parentino;
struct ucred *cred;
{
doff_t off;
struct dirtemplate dbuf;
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 | IO_NOMACCHECK, cred,
NOCRED, &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);
}
static int
ufs_dir_dd_ino(struct vnode *vp, struct ucred *cred, ino_t *dd_ino)
{
struct dirtemplate dirbuf;
int error, namlen;
if (vp->v_type != VDIR)
return (ENOTDIR);
error = vn_rdwr(UIO_READ, vp, (caddr_t)&dirbuf,
sizeof (struct dirtemplate), (off_t)0, UIO_SYSSPACE,
IO_NODELOCKED | IO_NOMACCHECK, cred, NOCRED, NULL, NULL);
if (error != 0)
return (error);
#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] != '.')
return (ENOTDIR);
*dd_ino = dirbuf.dotdot_ino;
return (0);
}
/*
* Check if source directory is in the path of the target directory.
*/
int
ufs_checkpath(ino_t source_ino, ino_t parent_ino, struct inode *target, struct ucred *cred, ino_t *wait_ino)
{
struct mount *mp;
struct vnode *tvp, *vp, *vp1;
int error;
ino_t dd_ino;
vp = tvp = ITOV(target);
mp = vp->v_mount;
*wait_ino = 0;
if (target->i_number == source_ino)
return (EEXIST);
if (target->i_number == parent_ino)
return (0);
if (target->i_number == ROOTINO)
return (0);
error = 0;
for (;;) {
error = ufs_dir_dd_ino(vp, cred, &dd_ino);
if (error != 0)
break;
if (dd_ino == source_ino) {
error = EINVAL;
break;
}
if (dd_ino == ROOTINO)
break;
if (dd_ino == parent_ino)
break;
error = VFS_VGET(mp, dd_ino, LK_SHARED | LK_NOWAIT, &vp1);
if (error != 0) {
*wait_ino = dd_ino;
break;
}
/* Recheck that ".." still points to vp1 after relock of vp */
error = ufs_dir_dd_ino(vp, cred, &dd_ino);
if (error != 0) {
vput(vp1);
break;
}
/* Redo the check of ".." if directory was reparented */
if (dd_ino != VTOI(vp1)->i_number) {
vput(vp1);
continue;
}
if (vp != tvp)
vput(vp);
vp = vp1;
}
if (error == ENOTDIR)
panic("checkpath: .. not a directory\n");
if (vp != tvp)
vput(vp);
return (error);
}
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