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68a9989171
freebsd-nq/sys/gnu/fs/ext2fs/ext2_lookup.c
Bruce Evans 68a9989171 Fixed spacefree calculation in ext2_direnter(). This bug sometimes caused 
panics.

This should be in 2.2, of course.

Submitted by:	davidg
Obtained from:	bouyer@antioche.ibp.fr (Manuel BOUYER) (fix for NetBSD)
1996-11-08 19:06:34 +00:00

1077 lines
32 KiB
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/*
* modified for Lites 1.1
*
* Aug 1995, Godmar Back (gback@cs.utah.edu)
* University of Utah, Department of Computer Science
*/
/*
* 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 8.6 (Berkeley) 4/1/94
*/
#if !defined(__FreeBSD__)
#include "diagnostic.h"
#endif
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/namei.h>
#include <sys/buf.h>
#include <sys/file.h>
#include <sys/mount.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <sys/dirent.h>
#include <ufs/ufs/quota.h>
#include <ufs/ufs/inode.h>
#include <ufs/ufs/dir.h>
#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/ufs_extern.h>
#include <gnu/ext2fs/ext2_extern.h>
#include <gnu/ext2fs/ext2_fs.h>
#include <gnu/ext2fs/ext2_fs_sb.h>
/*
DIRBLKSIZE in ffs is DEV_BSIZE (in most cases 512)
while it is the native blocksize in ext2fs - thus, a #define
is no longer appropriate
*/
#undef DIRBLKSIZ
extern int dirchk;
static void ext2_dirconv2ffs __P((struct ext2_dir_entry *e2dir,
struct dirent *ffsdir));
static int ext2_dirbadentry __P((struct vnode *dp,
struct ext2_dir_entry *de,
int entryoffsetinblock));
/*
* the problem that is tackled below is the fact that FFS
* includes the terminating zero on disk while EXT2FS doesn't
* this implies that we need to introduce some padding.
* For instance, a filename "sbin" has normally a reclen 12
* in EXT2, but 16 in FFS.
* This reminds me of that Pepsi commercial: 'Kid saved a lousy nine cents...'
* If it wasn't for that, the complete ufs code for directories would
* have worked w/o changes (except for the difference in DIRBLKSIZ)
*/
static void
ext2_dirconv2ffs( e2dir, ffsdir)
struct ext2_dir_entry *e2dir;
struct dirent *ffsdir;
{
struct dirent de;
bzero(&de, sizeof(struct dirent));
de.d_fileno = e2dir->inode;
de.d_namlen = e2dir->name_len;
#ifndef NO_HARDWIRED_CONSTANTS
if(e2dir->name_len + 8 == e2dir->rec_len)
de.d_reclen += 4;
de.d_type = DT_UNKNOWN; /* don't know more here */
strncpy(de.d_name, e2dir->name, e2dir->name_len);
de.d_name[de.d_namlen] = '\0';
/* Godmar thinks: since e2dir->rec_len can be big and means
nothing anyway, we compute our own reclen according to what
we think is right
*/
de.d_reclen = (de.d_namlen+8+1+3) & ~3;
bcopy(&de, ffsdir, de.d_reclen);
#endif
#if 0
printf("dirconv: ino %d rec old %d rec new %d nam %d name %s\n",
ffsdir->d_fileno, e2dir->rec_len, ffsdir->d_reclen,
ffsdir->d_namlen, ffsdir->d_name);
#endif
}
/*
* Vnode op for reading directories.
*
* The routine below assumes that the on-disk format of a directory
* is the same as that defined by <sys/dirent.h>. If the on-disk
* format changes, then it will be necessary to do a conversion
* from the on-disk format that read returns to the format defined
* by <sys/dirent.h>.
*/
/*
* this is exactly what we do here - the problem is that the conversion
* will blow up some entries by four bytes, so it can't be done in place.
* This is too bad. Right now the conversion is done entry by entry, the
* converted entry is sent via uiomove.
*
* XXX allocate a buffer, convert as many entries as possible, then send
* the whole buffer to uiomove
*/
int
ext2_readdir(ap)
struct vop_readdir_args /* {
struct vnode *a_vp;
struct uio *a_uio;
struct ucred *a_cred;
} */ *ap;
{
register struct uio *uio = ap->a_uio;
int count, error;
struct ext2_dir_entry *edp, *dp;
struct dirent dstdp;
struct uio auio;
struct iovec aiov;
caddr_t dirbuf;
int readcnt;
u_quad_t startoffset = uio->uio_offset;
count = uio->uio_resid; /* legyenek boldogok akik akarnak ... */
uio->uio_resid = count;
uio->uio_iov->iov_len = count;
#if 0
printf("ext2_readdir called uio->uio_offset %d uio->uio_resid %d count %d \n",
(int)uio->uio_offset, (int)uio->uio_resid, (int)count);
#endif
auio = *uio;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_segflg = UIO_SYSSPACE;
aiov.iov_len = count;
MALLOC(dirbuf, caddr_t, count, M_TEMP, M_WAITOK);
aiov.iov_base = dirbuf;
error = VOP_READ(ap->a_vp, &auio, 0, ap->a_cred);
if (error == 0) {
readcnt = count - auio.uio_resid;
edp = (struct ext2_dir_entry *)&dirbuf[readcnt];
for (dp = (struct ext2_dir_entry *)dirbuf;
!error && uio->uio_resid > 0 && dp < edp; ) {
ext2_dirconv2ffs(dp, &dstdp);
if (dp->rec_len > 0) {
if(dstdp.d_reclen <= uio->uio_resid) {
/* advance dp */
dp = (struct ext2_dir_entry *)
((char *)dp + dp->rec_len);
error =
uiomove((caddr_t)&dstdp,
dstdp.d_reclen, uio);
} else
break;
} else {
error = EIO;
break;
}
}
/* we need to correct uio_offset */
uio->uio_offset = startoffset + (caddr_t)dp - dirbuf;
}
FREE(dirbuf, M_TEMP);
return (error);
}
/*
* Convert a component of a pathname into a pointer to a locked inode.
* This is a very central and rather complicated routine.
* If the file system is not maintained in a strict tree hierarchy,
* this can result in a deadlock situation (see comments in code below).
*
* The cnp->cn_nameiop argument is LOOKUP, CREATE, RENAME, or DELETE depending
* on whether the name is to be looked up, created, renamed, or deleted.
* When CREATE, RENAME, or DELETE is specified, information usable in
* creating, renaming, or deleting a directory entry may be calculated.
* If flag has LOCKPARENT or'ed into it and the target of the pathname
* exists, lookup returns both the target and its parent directory locked.
* When creating or renaming and LOCKPARENT is specified, the target may
* not be ".". When deleting and LOCKPARENT is specified, the target may
* be "."., but the caller must check to ensure it does an vrele and vput
* instead of two vputs.
*
* Overall outline of ufs_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
ext2_lookup(ap)
struct vop_lookup_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 */
register struct ext2_dir_entry *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;
int DIRBLKSIZ = VTOI(ap->a_dvp)->i_e2fs->s_blocksize;
bp = NULL;
slotoffset = -1;
*vpp = NULL;
vdp = ap->a_dvp;
dp = VTOI(vdp);
lockparent = flags & LOCKPARENT;
wantparent = flags & (LOCKPARENT|WANTPARENT);
/*
* Check accessiblity of directory.
*/
if ((dp->i_mode & IFMT) != IFDIR)
return (ENOTDIR);
if (error = VOP_ACCESS(vdp, VEXEC, cred, cnp->cn_proc))
return (error);
/*
* 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 (error = cache_lookup(vdp, vpp, cnp)) {
int vpid; /* capability number of vnode */
if (error == ENOENT)
return (error);
/*
* Get the next vnode in the path.
* See comment below starting `Step through' for
* an explaination of the locking protocol.
*/
pdp = vdp;
dp = VTOI(*vpp);
vdp = *vpp;
vpid = vdp->v_id;
if (pdp == vdp) { /* lookup on "." */
VREF(vdp);
error = 0;
} else if (flags & ISDOTDOT) {
VOP_UNLOCK(pdp);
error = vget(vdp, 1);
if (!error && lockparent && (flags & ISLASTCN))
error = VOP_LOCK(pdp);
} else {
error = vget(vdp, 1);
if (!lockparent || error || !(flags & ISLASTCN))
VOP_UNLOCK(pdp);
}
/*
* Check that the capability number did not change
* while we were waiting for the lock.
*/
if (!error) {
if (vpid == vdp->v_id)
return (0);
vput(vdp);
if (lockparent && pdp != vdp && (flags & ISLASTCN))
VOP_UNLOCK(pdp);
}
if (error = VOP_LOCK(pdp))
return (error);
vdp = pdp;
dp = VTOI(pdp);
*vpp = NULL;
}
/*
* 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 = EXT2_DIR_REC_LEN(cnp->cn_namelen);
/* was
slotneeded = (sizeof(struct direct) - MAXNAMLEN +
cnp->cn_namelen + 3) &~ 3; */
}
/*
* 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 = VFSTOUFS(vdp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
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 = VOP_BLKATOFF(vdp, (off_t)dp->i_offset, NULL, &bp)))
return (error);
numdirpasses = 2;
nchstats.ncs_2passes++;
}
prevoff = dp->i_offset;
endsearch = roundup(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);
if (error =
VOP_BLKATOFF(vdp, (off_t)dp->i_offset, NULL, &bp))
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 ext2_dir_entry *)
((char *)bp->b_data + entryoffsetinblock);
if (ep->rec_len == 0 ||
(dirchk && ext2_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->rec_len;
if (ep->inode != 0)
size -= EXT2_DIR_REC_LEN(ep->name_len);
if (size > 0) {
if (size >= slotneeded) {
slotstatus = FOUND;
slotoffset = dp->i_offset;
slotsize = ep->rec_len;
} else if (slotstatus == NONE) {
slotfreespace += size;
if (slotoffset == -1)
slotoffset = dp->i_offset;
if (slotfreespace >= slotneeded) {
slotstatus = COMPACT;
slotsize = dp->i_offset +
ep->rec_len - slotoffset;
}
}
}
}
/*
* Check for a name match.
*/
if (ep->inode) {
namlen = ep->name_len;
if (namlen == cnp->cn_namelen &&
!bcmp(cnp->cn_nameptr, ep->name,
(unsigned)namlen)) {
/*
* Save directory entry's inode number and
* reclen in ndp->ni_ufs area, and release
* directory buffer.
*/
dp->i_ino = ep->inode;
dp->i_reclen = ep->rec_len;
brelse(bp);
goto found;
}
}
prevoff = dp->i_offset;
dp->i_offset += ep->rec_len;
entryoffsetinblock += ep->rec_len;
if (ep->inode)
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) &&
(flags & ISLASTCN) && dp->i_nlink != 0) {
/*
* Access for write is interpreted as allowing
* creation of files in the directory.
*/
if (error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_proc))
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 = roundup(dp->i_size, DIRBLKSIZ);
dp->i_count = 0;
enduseful = dp->i_offset;
} else {
dp->i_offset = slotoffset;
dp->i_count = slotsize;
if (enduseful < slotoffset + slotsize)
enduseful = slotoffset + slotsize;
}
dp->i_endoff = roundup(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);
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 (entryoffsetinblock + EXT2_DIR_REC_LEN(ep->name_len)
> dp->i_size) {
ufs_dirbad(dp, dp->i_offset, "i_size too small");
dp->i_size = entryoffsetinblock+EXT2_DIR_REC_LEN(ep->name_len);
dp->i_flag |= IN_CHANGE | IN_UPDATE;
}
/*
* 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.
*/
if (error = VOP_ACCESS(vdp, VWRITE, cred, cnp->cn_proc))
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 (error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp))
return (error);
/*
* If directory is "sticky", then user must own
* the directory, or the file in it, else she
* may not delete it (unless she's root). This
* implements append-only directories.
*/
if ((dp->i_mode & ISVTX) &&
cred->cr_uid != 0 &&
cred->cr_uid != dp->i_uid &&
VTOI(tdp)->i_uid != cred->cr_uid) {
vput(tdp);
return (EPERM);
}
*vpp = tdp;
if (!lockparent)
VOP_UNLOCK(vdp);
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_proc))
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 (error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp))
return (error);
*vpp = tdp;
cnp->cn_flags |= SAVENAME;
if (!lockparent)
VOP_UNLOCK(vdp);
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); /* race to get the inode */
if (error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp)) {
VOP_LOCK(pdp);
return (error);
}
if (lockparent && (flags & ISLASTCN) &&
(error = VOP_LOCK(pdp))) {
vput(tdp);
return (error);
}
*vpp = tdp;
} else if (dp->i_number == dp->i_ino) {
VREF(vdp); /* we want ourself, ie "." */
*vpp = vdp;
} else {
if (error = VFS_VGET(vdp->v_mount, dp->i_ino, &tdp))
return (error);
if (!lockparent || !(flags & ISLASTCN))
VOP_UNLOCK(pdp);
*vpp = tdp;
}
/*
* Insert name into cache if appropriate.
*/
if (cnp->cn_flags & MAKEENTRY)
cache_enter(vdp, *vpp, cnp);
return (0);
}
/*
* 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
*/
/*
* changed so that it confirms to ext2_check_dir_entry
*/
static int
ext2_dirbadentry(dp, de, entryoffsetinblock)
struct vnode *dp;
register struct ext2_dir_entry *de;
int entryoffsetinblock;
{
int DIRBLKSIZ = VTOI(dp)->i_e2fs->s_blocksize;
char * error_msg = NULL;
if (de->rec_len < EXT2_DIR_REC_LEN(1))
error_msg = "rec_len is smaller than minimal";
else if (de->rec_len % 4 != 0)
error_msg = "rec_len % 4 != 0";
else if (de->rec_len < EXT2_DIR_REC_LEN(de->name_len))
error_msg = "reclen is too small for name_len";
else if (entryoffsetinblock + de->rec_len > DIRBLKSIZ)
error_msg = "directory entry across blocks";
/* else LATER
if (de->inode > dir->i_sb->u.ext2_sb.s_es->s_inodes_count)
error_msg = "inode out of bounds";
*/
if (error_msg != NULL)
printf( "bad directory entry: %s\n"
"offset=%lu, inode=%lu, rec_len=%d, name_len=%d \n",
error_msg, entryoffsetinblock,
(unsigned long) de->inode, de->rec_len, de->name_len);
return error_msg == NULL ? 0 : 1;
}
/*
* Write a directory entry after a call to namei, using the parameters
* that it left in nameidata. The argument ip is the inode which the new
* directory entry will refer to. Dvp is a pointer to the directory to
* be written, which was left locked by namei. Remaining parameters
* (dp->i_offset, dp->i_count) indicate how the space for the new
* entry is to be obtained.
*/
int
ext2_direnter(ip, dvp, cnp)
struct inode *ip;
struct vnode *dvp;
register struct componentname *cnp;
{
register struct ext2_dir_entry *ep, *nep;
register struct inode *dp;
struct buf *bp;
struct ext2_dir_entry newdir;
struct iovec aiov;
struct uio auio;
u_int dsize;
int error, loc, newentrysize, spacefree;
char *dirbuf;
int DIRBLKSIZ = ip->i_e2fs->s_blocksize;
#if DIAGNOSTIC
if ((cnp->cn_flags & SAVENAME) == 0)
panic("direnter: missing name");
#endif
dp = VTOI(dvp);
newdir.inode = ip->i_number;
newdir.name_len = cnp->cn_namelen;
bcopy(cnp->cn_nameptr, newdir.name, (unsigned)cnp->cn_namelen + 1);
newentrysize = EXT2_DIR_REC_LEN(newdir.name_len);
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("ext2_direnter: newblk");
auio.uio_offset = dp->i_offset;
newdir.rec_len = DIRBLKSIZ;
auio.uio_resid = newentrysize;
aiov.iov_len = newentrysize;
aiov.iov_base = (caddr_t)&newdir;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_rw = UIO_WRITE;
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_procp = (struct proc *)0;
error = VOP_WRITE(dvp, &auio, IO_SYNC, cnp->cn_cred);
if (DIRBLKSIZ >
VFSTOUFS(dvp->v_mount)->um_mountp->mnt_stat.f_bsize)
/* XXX should grow with balloc() */
panic("ext2_direnter: frag size");
else if (!error) {
dp->i_size = roundup(dp->i_size, DIRBLKSIZ);
dp->i_flag |= IN_CHANGE;
}
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.
*/
if (error = VOP_BLKATOFF(dvp, (off_t)dp->i_offset, &dirbuf, &bp))
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 ext2_dir_entry *)dirbuf;
dsize = EXT2_DIR_REC_LEN(ep->name_len);
spacefree = ep->rec_len - dsize;
for (loc = ep->rec_len; loc < dp->i_count; ) {
nep = (struct ext2_dir_entry *)(dirbuf + loc);
if (ep->inode) {
/* trim the existing slot */
ep->rec_len = dsize;
ep = (struct ext2_dir_entry *)((char *)ep + dsize);
} else {
/* overwrite; nothing there; header is ours */
spacefree += dsize;
}
dsize = EXT2_DIR_REC_LEN(nep->name_len);
spacefree += nep->rec_len - dsize;
loc += nep->rec_len;
bcopy((caddr_t)nep, (caddr_t)ep, dsize);
}
/*
* Update the pointer fields in the previous entry (if any),
* copy in the new entry, and write out the block.
*/
if (ep->inode == 0) {
if (spacefree + dsize < newentrysize)
panic("ext2_direnter: compact1");
newdir.rec_len = spacefree + dsize;
} else {
if (spacefree < newentrysize)
panic("ext2_direnter: compact2");
newdir.rec_len = spacefree;
ep->rec_len = dsize;
ep = (struct ext2_dir_entry *)((char *)ep + dsize);
}
bcopy((caddr_t)&newdir, (caddr_t)ep, (u_int)newentrysize);
error = VOP_BWRITE(bp);
dp->i_flag |= IN_CHANGE | IN_UPDATE;
if (!error && dp->i_endoff && dp->i_endoff < dp->i_size)
error = VOP_TRUNCATE(dvp, (off_t)dp->i_endoff, IO_SYNC,
cnp->cn_cred, cnp->cn_proc);
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
ext2_dirremove(dvp, cnp)
struct vnode *dvp;
struct componentname *cnp;
{
register struct inode *dp;
struct ext2_dir_entry *ep;
struct buf *bp;
int error;
dp = VTOI(dvp);
if (dp->i_count == 0) {
/*
* First entry in block: set d_ino to zero.
*/
if (error =
VOP_BLKATOFF(dvp, (off_t)dp->i_offset, (char **)&ep, &bp))
return (error);
ep->inode = 0;
error = VOP_BWRITE(bp);
dp->i_flag |= IN_CHANGE | IN_UPDATE;
return (error);
}
/*
* Collapse new free space into previous entry.
*/
if (error = VOP_BLKATOFF(dvp, (off_t)(dp->i_offset - dp->i_count),
(char **)&ep, &bp))
return (error);
ep->rec_len += dp->i_reclen;
error = VOP_BWRITE(bp);
dp->i_flag |= IN_CHANGE | IN_UPDATE;
return (error);
}
/*
* Rewrite an existing directory entry to point at the inode
* supplied. The parameters describing the directory entry are
* set up by a call to namei.
*/
int
ext2_dirrewrite(dp, ip, cnp)
struct inode *dp, *ip;
struct componentname *cnp;
{
struct buf *bp;
struct ext2_dir_entry *ep;
struct vnode *vdp = ITOV(dp);
int error;
if (error = VOP_BLKATOFF(vdp, (off_t)dp->i_offset, (char **)&ep, &bp))
return (error);
ep->inode = ip->i_number;
error = VOP_BWRITE(bp);
dp->i_flag |= IN_CHANGE | IN_UPDATE;
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
ext2_dirempty(ip, parentino, cred)
register struct inode *ip;
ino_t parentino;
struct ucred *cred;
{
register off_t off;
struct dirtemplate dbuf;
register struct ext2_dir_entry *dp = (struct ext2_dir_entry *)&dbuf;
int error, count, namlen;
#define MINDIRSIZ (sizeof (struct dirtemplate) / 2)
for (off = 0; off < ip->i_size; off += dp->rec_len) {
error = vn_rdwr(UIO_READ, ITOV(ip), (caddr_t)dp, MINDIRSIZ, off,
UIO_SYSSPACE, IO_NODELOCKED, cred, &count, (struct proc *)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->rec_len == 0)
return (0);
/* skip empty entries */
if (dp->inode == 0)
continue;
/* accept only "." and ".." */
namlen = dp->name_len;
if (namlen > 2)
return (0);
if (dp->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)
continue;
if (dp->name[1] == '.' && dp->inode == 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
ext2_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 proc *)0);
if (error != 0)
break;
namlen = dirbuf.dotdot_namlen;
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);
if (error = VFS_VGET(vp->v_mount, dirbuf.dotdot_ino, &vp)) {
vp = NULL;
break;
}
}
out:
if (error == ENOTDIR)
printf("checkpath: .. not a directory\n");
if (vp != NULL)
vput(vp);
return (error);
}
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