NetBSD/sys/msdosfs/msdosfs_denode.c

622 lines
16 KiB
C

/*
* Written by Paul Popelka (paulp@uts.amdahl.com)
*
* You can do anything you want with this software, just don't say you wrote
* it, and don't reoove this notice.
*
* This software is provided "as is".
*
* The authop supplies this software to be publicly redistributed on the
* understanding that the author is not responsible for the correct
* functioning of this software in any circumstances and is not liable for
* any damages caused by this software.
*
* October 1992
*
* $Id: msdosfs_denode.c,v 1.1 1993/08/13 11:35:35 cgd Exp $
*/
#include "param.h"
#include "systm.h"
#include "mount.h"
#include "proc.h"
#include "buf.h"
#include "vnode.h"
#include "kernel.h" /* defines "time" */
#include "bpb.h"
#include "msdosfsmount.h"
#include "direntry.h"
#include "denode.h"
#include "fat.h"
#define DEHSZ 512
#if ((DEHSZ & (DEHSZ-1)) == 0)
#define DEHASH(dev, deno) (((dev)+(deno)+((deno)>>16))&(DEHSZ-1))
#else
#define DEHASH(dev, deno) (((dev)+(deno)+((deno)>>16))%DEHSZ)
#endif /* ((DEHSZ & (DEHSZ-1)) == 0) */
union dehead {
union dehead *deh_head[2];
struct denode *deh_chain[2];
} dehead[DEHSZ];
msdosfs_init()
{
int i;
union dehead *deh;
if (VN_MAXPRIVATE < sizeof(struct denode))
panic("msdosfs_init: vnode too small");
for (i = DEHSZ, deh = dehead; --i >= 0; deh++) {
deh->deh_head[0] = deh;
deh->deh_head[1] = deh;
}
}
/*
* If deget() succeeds it returns with the gotten denode locked().
* pmp - address of msdosfsmount structure of the filesystem
* containing the denode of interest. The pm_dev field and the address
* of the msdosfsmount structure are used.
* dirclust - which cluster bp contains, if dirclust is 0 (root directory)
* diroffset is relative to the beginning of the root directory, otherwise
* it is cluster relative.
* diroffset - offset past begin of cluster of denode we want
* direntptr - address of the direntry structure of interest. direntptr
* is NULL, the block is read if necessary.
* depp - returns the address of the gotten denode.
*/
int
deget(pmp, dirclust, diroffset, direntptr, depp)
struct msdosfsmount *pmp; /* so we know the maj/min number */
u_long dirclust; /* cluster this dir entry came from */
u_long diroffset; /* index of entry within the cluster */
struct direntry *direntptr;
struct denode **depp; /* returns the addr of the gotten denode */
{
int error;
dev_t dev = pmp->pm_dev;
union dehead *deh;
struct mount *mntp = pmp->pm_mountp;
extern struct vnodeops msdosfs_vnodeops;
struct denode *ldep;
struct vnode *nvp;
struct buf *bp;
#if defined(MSDOSFSDEBUG)
printf("deget(pmp %08x, dirclust %d, diroffset %x, direntptr %x, depp %08x)\n",
pmp, dirclust, diroffset, direntptr, depp);
#endif /* defined(MSDOSFSDEBUG) */
/*
* If dir entry is given and refers to a directory, convert to
* canonical form
*/
if (direntptr && (direntptr->deAttributes & ATTR_DIRECTORY)) {
dirclust = direntptr->deStartCluster;
if (dirclust == MSDOSFSROOT)
diroffset = MSDOSFSROOT_OFS;
else
diroffset = 0;
}
/*
* See if the denode is in the denode cache. Use the location of
* the directory entry to compute the hash value. For subdir use
* address of "." entry. for root dir use cluster MSDOSFSROOT,
* offset MSDOSFSROOT_OFS
*
* NOTE: The check for de_refcnt > 0 below insures the denode being
* examined does not represent an unlinked but still open file.
* These files are not to be accessible even when the directory
* entry that represented the file happens to be reused while the
* deleted file is still open.
*/
deh = &dehead[DEHASH(dev, dirclust + diroffset)];
loop:
for (ldep = deh->deh_chain[0]; ldep != (struct denode *) deh;
ldep = ldep->de_forw) {
if (dev != ldep->de_dev || ldep->de_refcnt == 0)
continue;
if (dirclust != ldep->de_dirclust
|| diroffset != ldep->de_diroffset)
continue;
if (ldep->de_flag & DELOCKED) {
/*
* should we brelse() the passed buf hdr to avoid
* some potential deadlock?
*/
ldep->de_flag |= DEWANT;
sleep((caddr_t) ldep, PINOD);
goto loop;
}
if (vget(DETOV(ldep)))
goto loop;
*depp = ldep;
return 0;
}
/*
* Directory entry was not in cache, have to create a vnode and
* copy it from the passed disk buffer.
*/
/* getnewvnode() does a VREF() on the vnode */
if (error = getnewvnode(VT_MSDOSFS, mntp, &msdosfs_vnodeops, &nvp)) {
*depp = 0;
return error;
}
ldep = VTODE(nvp);
ldep->de_vnode = nvp;
ldep->de_flag = 0;
ldep->de_devvp = 0;
ldep->de_lockf = 0;
ldep->de_dev = dev;
fc_purge(ldep, 0); /* init the fat cache for this denode */
/*
* Insert the denode into the hash queue and lock the denode so it
* can't be accessed until we've read it in and have done what we
* need to it.
*/
insque(ldep, deh);
DELOCK(ldep);
/*
* Copy the directory entry into the denode area of the vnode.
*/
if (dirclust == MSDOSFSROOT && diroffset == MSDOSFSROOT_OFS) {
/*
* Directory entry for the root directory. There isn't one,
* so we manufacture one. We should probably rummage
* through the root directory and find a label entry (if it
* exists), and then use the time and date from that entry
* as the time and date for the root denode.
*/
ldep->de_Attributes = ATTR_DIRECTORY;
ldep->de_StartCluster = MSDOSFSROOT;
ldep->de_FileSize = pmp->pm_rootdirsize * pmp->pm_BytesPerSec;
/*
* fill in time and date so that dos2unixtime() doesn't
* spit up when called from msdosfs_getattr() with root
* denode
*/
ldep->de_Time = 0x0000; /* 00:00:00 */
ldep->de_Date = (0 << 9) | (1 << 5) | (1 << 0);
/* Jan 1, 1980 */
/* leave the other fields as garbage */
}
else {
bp = NULL;
if (!direntptr) {
error = readep(pmp, dirclust, diroffset, &bp,
&direntptr);
if (error)
return error;
}
ldep->de_de = *direntptr;
if (bp)
brelse(bp);
}
/*
* Fill in a few fields of the vnode and finish filling in the
* denode. Then return the address of the found denode.
*/
ldep->de_pmp = pmp;
ldep->de_devvp = pmp->pm_devvp;
ldep->de_refcnt = 1;
ldep->de_dirclust = dirclust;
ldep->de_diroffset = diroffset;
if (ldep->de_Attributes & ATTR_DIRECTORY) {
/*
* Since DOS directory entries that describe directories
* have 0 in the filesize field, we take this opportunity
* to find out the length of the directory and plug it into
* the denode structure.
*/
u_long size;
nvp->v_type = VDIR;
if (ldep->de_StartCluster == MSDOSFSROOT)
nvp->v_flag |= VROOT;
else {
error = pcbmap(ldep, 0xffff, 0, &size);
if (error == E2BIG) {
ldep->de_FileSize = size << pmp->pm_cnshift;
error = 0;
}
else
printf("deget(): pcbmap returned %d\n", error);
}
}
else
nvp->v_type = VREG;
VREF(ldep->de_devvp);
*depp = ldep;
return 0;
}
void
deput(dep)
struct denode *dep;
{
if ((dep->de_flag & DELOCKED) == 0)
panic("deput: denode not locked");
DEUNLOCK(dep);
vrele(DETOV(dep));
}
int
deupdat(dep, tp, waitfor)
struct denode *dep;
struct timeval *tp;
int waitfor;
{
int error;
daddr_t bn;
int diro;
struct buf *bp;
struct direntry *dirp;
struct msdosfsmount *pmp = dep->de_pmp;
struct vnode *vp = DETOV(dep);
#if defined(MSDOSFSDEBUG)
printf("deupdat(): dep %08x\n", dep);
#endif /* defined(MSDOSFSDEBUG) */
/*
* If the update bit is off, or this denode is from a readonly
* filesystem, or this denode is for a directory, or the denode
* represents an open but unlinked file then don't do anything. DOS
* directory entries that describe a directory do not ever get
* updated. This is the way dos treats them.
*/
if ((dep->de_flag & DEUPD) == 0 ||
vp->v_mount->mnt_flag & MNT_RDONLY ||
dep->de_Attributes & ATTR_DIRECTORY ||
dep->de_refcnt <= 0)
return 0;
/*
* Read in the cluster containing the directory entry we want to
* update.
*/
if (error = readde(dep, &bp, &dirp))
return error;
/*
* Put the passed in time into the directory entry.
*/
unix2dostime(&time, (union dosdate *) & dep->de_Date,
(union dostime *) & dep->de_Time);
dep->de_flag &= ~DEUPD;
/*
* Copy the directory entry out of the denode into the cluster it
* came from.
*/
*dirp = dep->de_de; /* structure copy */
/*
* Write the cluster back to disk. If they asked for us to wait
* for the write to complete, then use bwrite() otherwise use
* bdwrite().
*/
error = 0; /* note that error is 0 from above, but ... */
if (waitfor)
error = bwrite(bp);
else
bdwrite(bp);
return error;
}
/*
* Truncate the file described by dep to the length specified by length.
*/
int
detrunc(dep, length, flags)
struct denode *dep;
u_long length;
int flags;
{
int error;
int allerror;
u_long eofentry;
u_long chaintofree;
daddr_t bn;
int boff;
int isadir = dep->de_Attributes & ATTR_DIRECTORY;
struct buf *bp;
struct msdosfsmount *pmp = dep->de_pmp;
#if defined(MSDOSFSDEBUG)
printf("detrunc(): file %s, length %d, flags %d\n", dep->de_Name, length, flags);
#endif /* defined(MSDOSFSDEBUG) */
/*
* Disallow attempts to truncate the root directory since it is of
* fixed size. That's just the way dos filesystems are. We use
* the VROOT bit in the vnode because checking for the directory
* bit and a startcluster of 0 in the denode is not adequate to
* recognize the root directory at this point in a file or
* directory's life.
*/
if (DETOV(dep)->v_flag & VROOT) {
printf("detrunc(): can't truncate root directory, clust %d, offset %d\n",
dep->de_dirclust, dep->de_diroffset);
return EINVAL;
}
vnode_pager_setsize(DETOV(dep), length);
if (dep->de_FileSize <= length) {
dep->de_flag |= DEUPD;
error = deupdat(dep, &time, 1);
#if defined(MSDOSFSDEBUG)
printf("detrunc(): file is shorter return point, errno %d\n", error);
#endif /* defined(MSDOSFSDEBUG) */
return error;
}
/*
* If the desired length is 0 then remember the starting cluster of
* the file and set the StartCluster field in the directory entry
* to 0. If the desired length is not zero, then get the number of
* the last cluster in the shortened file. Then get the number of
* the first cluster in the part of the file that is to be freed.
* Then set the next cluster pointer in the last cluster of the
* file to CLUST_EOFE.
*/
if (length == 0) {
chaintofree = dep->de_StartCluster;
dep->de_StartCluster = 0;
eofentry = ~0;
}
else {
error = pcbmap(dep, (length - 1) >> pmp->pm_cnshift,
0, &eofentry);
if (error) {
#if defined(MSDOSFSDEBUG)
printf("detrunc(): pcbmap fails %d\n", error);
#endif /* defined(MSDOSFSDEBUG) */
return error;
}
}
fc_purge(dep, (length + pmp->pm_crbomask) >> pmp->pm_cnshift);
/*
* If the new length is not a multiple of the cluster size then we
* must zero the tail end of the new last cluster in case it
* becomes part of the file again because of a seek.
*/
if ((boff = length & pmp->pm_crbomask) != 0) {
/*
* should read from file vnode or filesystem vnode
* depending on if file or dir
*/
if (isadir) {
bn = cntobn(pmp, eofentry);
error = bread(pmp->pm_devvp, bn, pmp->pm_bpcluster,
NOCRED, &bp);
}
else {
bn = (length - 1) >> pmp->pm_cnshift;
error = bread(DETOV(dep), bn, pmp->pm_bpcluster,
NOCRED, &bp);
}
if (error) {
#if defined(MSDOSFSDEBUG)
printf("detrunc(): bread fails %d\n", error);
#endif /* defined(MSDOSFSDEBUG) */
return error;
}
vnode_pager_uncache(DETOV(dep)); /* what's this for? */
/*
* is this the right place for it?
*/
bzero(bp->b_un.b_addr + boff, pmp->pm_bpcluster - boff);
if (flags & IO_SYNC)
bwrite(bp);
else
bdwrite(bp);
}
/*
* Write out the updated directory entry. Even if the update fails
* we free the trailing clusters.
*/
dep->de_FileSize = length;
dep->de_flag |= DEUPD;
vinvalbuf(DETOV(dep), length > 0);
allerror = deupdat(dep, &time, MNT_WAIT);
#if defined(MSDOSFSDEBUG)
printf("detrunc(): allerror %d, eofentry %d\n",
allerror, eofentry);
#endif /* defined(MSDOSFSDEBUG) */
/*
* If we need to break the cluster chain for the file then do it
* now.
*/
if (eofentry != ~0) {
error = fatentry(FAT_GET_AND_SET, pmp, eofentry,
&chaintofree, CLUST_EOFE);
if (error) {
#if defined(MSDOSFSDEBUG)
printf("detrunc(): fatentry errors %d\n", error);
#endif /* defined(MSDOSFSDEBUG) */
return error;
}
fc_setcache(dep, FC_LASTFC, (length - 1) >> pmp->pm_cnshift,
eofentry);
}
/*
* Now free the clusters removed from the file because of the
* truncation.
*/
if (chaintofree != 0 && !MSDOSFSEOF(chaintofree))
freeclusterchain(pmp, chaintofree);
return allerror;
}
/*
* Move a denode to its correct hash queue after the file it represents has
* been moved to a new directory.
*/
reinsert(dep)
struct denode *dep;
{
struct msdosfsmount *pmp = dep->de_pmp;
union dehead *deh;
/*
* Fix up the denode cache. If the denode is for a directory,
* there is nothing to do since the hash is based on the starting
* cluster of the directory file and that hasn't changed. If for a
* file the hash is based on the location of the directory entry,
* so we must remove it from the cache and re-enter it with the
* hash based on the new location of the directory entry.
*/
if ((dep->de_Attributes & ATTR_DIRECTORY) == 0) {
remque(dep);
deh = &dehead[DEHASH(pmp->pm_dev,
dep->de_dirclust + dep->de_diroffset)];
insque(dep, deh);
}
}
int msdosfs_prtactive; /* print reclaims of active vnodes */
int
msdosfs_reclaim(vp)
struct vnode *vp;
{
struct denode *dep = VTODE(vp);
int i;
#if defined(MSDOSFSDEBUG)
printf("msdosfs_reclaim(): dep %08x, file %s, refcnt %d\n",
dep, dep->de_Name, dep->de_refcnt);
#endif /* defined(MSDOSFSDEBUG) */
if (msdosfs_prtactive && vp->v_usecount != 0)
vprint("msdosfs_reclaim(): pushing active", vp);
/*
* Remove the denode from the denode hash chain we are in.
*/
remque(dep);
dep->de_forw = dep;
dep->de_back = dep;
cache_purge(vp);
/*
* Indicate that one less file on the filesystem is open.
*/
if (dep->de_devvp) {
vrele(dep->de_devvp);
dep->de_devvp = 0;
}
dep->de_flag = 0;
return 0;
}
int
msdosfs_inactive(vp, p)
struct vnode *vp;
struct proc *p;
{
struct denode *dep = VTODE(vp);
int error = 0;
#if defined(MSDOSFSDEBUG)
printf("msdosfs_inactive(): dep %08x, de_Name[0] %x\n", dep, dep->de_Name[0]);
#endif /* defined(MSDOSFSDEBUG) */
if (msdosfs_prtactive && vp->v_usecount != 0)
vprint("msdosfs_inactive(): pushing active", vp);
/*
* Get rid of denodes related to stale file handles. Hmmm, what
* does this really do?
*/
if (dep->de_Name[0] == SLOT_DELETED) {
if ((vp->v_flag & VXLOCK) == 0)
vgone(vp);
return 0;
}
/*
* If the file has been deleted and it is on a read/write
* filesystem, then truncate the file, and mark the directory slot
* as empty. (This may not be necessary for the dos filesystem.
*/
#if defined(MSDOSFSDEBUG)
printf("msdosfs_inactive(): dep %08x, refcnt %d, mntflag %x, MNT_RDONLY %x\n",
dep, dep->de_refcnt, vp->v_mount->mnt_flag, MNT_RDONLY);
#endif /* defined(MSDOSFSDEBUG) */
DELOCK(dep);
if (dep->de_refcnt <= 0 && (vp->v_mount->mnt_flag & MNT_RDONLY) == 0) {
error = detrunc(dep, (u_long) 0, 0);
dep->de_flag |= DEUPD;
dep->de_Name[0] = SLOT_DELETED;
}
DEUPDAT(dep, &time, 0);
DEUNLOCK(dep);
dep->de_flag = 0;
/*
* If we are done with the denode, then reclaim it so that it can
* be reused now.
*/
#if defined(MSDOSFSDEBUG)
printf("msdosfs_inactive(): v_usecount %d, de_Name[0] %x\n", vp->v_usecount,
dep->de_Name[0]);
#endif /* defined(MSDOSFSDEBUG) */
if (vp->v_usecount == 0 && dep->de_Name[0] == SLOT_DELETED)
vgone(vp);
return error;
}
int
delock(dep)
struct denode *dep;
{
while (dep->de_flag & DELOCKED) {
dep->de_flag |= DEWANT;
if (dep->de_spare0 == curproc->p_pid)
panic("delock: locking against myself");
dep->de_spare1 = curproc->p_pid;
(void) sleep((caddr_t) dep, PINOD);
}
dep->de_spare1 = 0;
dep->de_spare0 = curproc->p_pid;
dep->de_flag |= DELOCKED;
return 0;
}
int
deunlock(dep)
struct denode *dep;
{
if ((dep->de_flag & DELOCKED) == 0)
vprint("deunlock: found unlocked denode", DETOV(dep));
dep->de_spare0 = 0;
dep->de_flag &= ~DELOCKED;
if (dep->de_flag & DEWANT) {
dep->de_flag &= ~DEWANT;
wakeup((caddr_t) dep);
}
return 0;
}