/*
* Read in the disk block containing the directory entry (dirclu, dirofs)
* and return the address of the buf header, and the address of the
* directory entry within the block.
*/
int
readep(struct msdosfsmount *pmp, u_long dirclust, u_long diroffset, struct buf **bpp, struct direntry **epp)
{
int error;
daddr_t bn;
int blsize;
blsize = pmp->pm_bpcluster;
if (dirclust == MSDOSFSROOT
&& de_blk(pmp, diroffset + blsize) > pmp->pm_rootdirsize)
blsize = de_bn2off(pmp, pmp->pm_rootdirsize) & pmp->pm_crbomask;
bn = detobn(pmp, dirclust, diroffset);
if ((error = bread(pmp->pm_devvp, de_bn2kb(pmp, bn), blsize, NOCRED,
0, bpp)) != 0) {
*bpp = NULL;
return (error);
}
if (epp)
*epp = bptoep(pmp, *bpp, diroffset);
return (0);
}
/*
* Truncate the file described by dep to the length specified by length.
*/
int
detrunc(struct denode *dep, uint32_t length, int flags, struct ucred *cred,
struct proc *p)
{
int error;
int allerror;
int vflags;
uint32_t eofentry;
uint32_t chaintofree = 0;
daddr_t bn;
int boff;
int isadir = dep->de_Attributes & ATTR_DIRECTORY;
struct buf *bp;
struct msdosfsmount *pmp = dep->de_pmp;
#ifdef MSDOSFS_DEBUG
printf("detrunc(): file %.11s, length %ld, flags %d\n",
dep->de_Name, length, flags);
#endif
/*
* 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) && !FAT32(pmp)) {
printf("detrunc(): can't truncate root directory, clust %u, offset %u\n",
dep->de_dirclust, dep->de_diroffset);
return (EINVAL);
}
uvm_vnp_setsize(DETOV(dep), length);
if (dep->de_FileSize < length)
return (deextend(dep, length, cred));
/*
* 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, de_clcount(pmp, length) - 1, 0,
&eofentry, 0);
if (error) {
#ifdef MSDOSFS_DEBUG
printf("detrunc(): pcbmap fails %d\n", error);
#endif
return (error);
}
}
fc_purge(dep, de_clcount(pmp, length));
/*
* 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) {
if (isadir) {
bn = cntobn(pmp, eofentry);
error = bread(pmp->pm_devvp, bn, pmp->pm_bpcluster, &bp);
} else {
bn = de_blk(pmp, length);
error = bread(DETOV(dep), bn, pmp->pm_bpcluster, &bp);
}
if (error) {
brelse(bp);
#ifdef MSDOSFS_DEBUG
printf("detrunc(): bread fails %d\n", error);
#endif
return (error);
}
uvm_vnp_uncache(DETOV(dep));
/*
* is this the right place for it?
*/
bzero(bp->b_data + 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;
if (!isadir)
dep->de_flag |= DE_UPDATE|DE_MODIFIED;
vflags = (length > 0 ? V_SAVE : 0) | V_SAVEMETA;
vinvalbuf(DETOV(dep), vflags, cred, p, 0, 0);
allerror = deupdat(dep, 1);
#ifdef MSDOSFS_DEBUG
printf("detrunc(): allerror %d, eofentry %d\n",
allerror, eofentry);
#endif
/*
* 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) {
#ifdef MSDOSFS_DEBUG
printf("detrunc(): fatentry errors %d\n", error);
#endif
return (error);
}
fc_setcache(dep, FC_LASTFC, de_cluster(pmp, length - 1),
eofentry);
}
/*
* Now free the clusters removed from the file because of the
* truncation.
*/
if (chaintofree != 0 && !MSDOSFSEOF(pmp, chaintofree))
freeclusterchain(pmp, chaintofree);
return (allerror);
}
/*
* Write data to a file or directory.
*/
int
msdosfs_write(void *v)
{
struct vop_write_args *ap = v;
int n;
int croffset;
int resid;
uint32_t osize;
int error = 0;
uint32_t count, lastcn;
daddr64_t bn;
struct buf *bp;
int ioflag = ap->a_ioflag;
struct uio *uio = ap->a_uio;
struct proc *p = uio->uio_procp;
struct vnode *vp = ap->a_vp;
struct vnode *thisvp;
struct denode *dep = VTODE(vp);
struct msdosfsmount *pmp = dep->de_pmp;
struct ucred *cred = ap->a_cred;
#ifdef MSDOSFS_DEBUG
printf("msdosfs_write(vp %08x, uio %08x, ioflag %08x, cred %08x\n",
vp, uio, ioflag, cred);
printf("msdosfs_write(): diroff %d, dirclust %d, startcluster %d\n",
dep->de_diroffset, dep->de_dirclust, dep->de_StartCluster);
#endif
switch (vp->v_type) {
case VREG:
if (ioflag & IO_APPEND)
uio->uio_offset = dep->de_FileSize;
thisvp = vp;
break;
case VDIR:
return EISDIR;
default:
panic("msdosfs_write(): bad file type");
}
if (uio->uio_offset < 0)
return (EINVAL);
if (uio->uio_resid == 0)
return (0);
/* Don't bother to try to write files larger than the f/s limit */
if (uio->uio_offset + uio->uio_resid > MSDOSFS_FILESIZE_MAX)
return (EFBIG);
/*
* If they've exceeded their filesize limit, tell them about it.
*/
if (p &&
((uio->uio_offset + uio->uio_resid) >
p->p_rlimit[RLIMIT_FSIZE].rlim_cur)) {
psignal(p, SIGXFSZ);
return (EFBIG);
}
/*
* If the offset we are starting the write at is beyond the end of
* the file, then they've done a seek. Unix filesystems allow
* files with holes in them, DOS doesn't so we must fill the hole
* with zeroed blocks.
*/
if (uio->uio_offset > dep->de_FileSize) {
if ((error = deextend(dep, uio->uio_offset, cred)) != 0)
return (error);
}
/*
* Remember some values in case the write fails.
*/
resid = uio->uio_resid;
osize = dep->de_FileSize;
/*
* If we write beyond the end of the file, extend it to its ultimate
* size ahead of the time to hopefully get a contiguous area.
*/
if (uio->uio_offset + resid > osize) {
count = de_clcount(pmp, uio->uio_offset + resid) -
de_clcount(pmp, osize);
if ((error = extendfile(dep, count, NULL, NULL, 0)) &&
(error != ENOSPC || (ioflag & IO_UNIT)))
goto errexit;
lastcn = dep->de_fc[FC_LASTFC].fc_frcn;
} else
lastcn = de_clcount(pmp, osize) - 1;
do {
if (de_cluster(pmp, uio->uio_offset) > lastcn) {
error = ENOSPC;
break;
}
bn = de_blk(pmp, uio->uio_offset);
if ((uio->uio_offset & pmp->pm_crbomask) == 0
&& (de_blk(pmp, uio->uio_offset + uio->uio_resid) > de_blk(pmp, uio->uio_offset)
|| uio->uio_offset + uio->uio_resid >= dep->de_FileSize)) {
/*
* If either the whole cluster gets written,
* or we write the cluster from its start beyond EOF,
* then no need to read data from disk.
*/
bp = getblk(thisvp, bn, pmp->pm_bpcluster, 0, 0);
clrbuf(bp);
/*
* Do the bmap now, since pcbmap needs buffers
* for the fat table. (see msdosfs_strategy)
*/
if (bp->b_blkno == bp->b_lblkno) {
error = pcbmap(dep,
de_bn2cn(pmp, bp->b_lblkno),
&bp->b_blkno, 0, 0);
if (error)
bp->b_blkno = -1;
}
if (bp->b_blkno == -1) {
brelse(bp);
if (!error)
error = EIO; /* XXX */
break;
}
} else {
/*
* The block we need to write into exists, so read it in.
*/
error = bread(thisvp, bn, pmp->pm_bpcluster,
NOCRED, &bp);
if (error) {
brelse(bp);
break;
}
}
croffset = uio->uio_offset & pmp->pm_crbomask;
n = min(uio->uio_resid, pmp->pm_bpcluster - croffset);
if (uio->uio_offset + n > dep->de_FileSize) {
dep->de_FileSize = uio->uio_offset + n;
uvm_vnp_setsize(vp, dep->de_FileSize);
}
uvm_vnp_uncache(vp);
/*
* Should these vnode_pager_* functions be done on dir
* files?
*/
/*
* Copy the data from user space into the buf header.
*/
error = uiomove(bp->b_data + croffset, n, uio);
/*
* If they want this synchronous then write it and wait for
* it. Otherwise, if on a cluster boundary write it
* asynchronously so we can move on to the next block
* without delay. Otherwise do a delayed write because we
* may want to write somemore into the block later.
*/
if (ioflag & IO_SYNC)
(void) bwrite(bp);
else if (n + croffset == pmp->pm_bpcluster)
bawrite(bp);
else
bdwrite(bp);
dep->de_flag |= DE_UPDATE;
} while (error == 0 && uio->uio_resid > 0);
/*
* If the write failed and they want us to, truncate the file back
* to the size it was before the write was attempted.
*/
errexit:
if (error) {
if (ioflag & IO_UNIT) {
detrunc(dep, osize, ioflag & IO_SYNC, NOCRED, NULL);
uio->uio_offset -= resid - uio->uio_resid;
uio->uio_resid = resid;
} else {
detrunc(dep, dep->de_FileSize, ioflag & IO_SYNC, NOCRED, NULL);
if (uio->uio_resid != resid)
error = 0;
}
} else if (ioflag & IO_SYNC)
error = deupdat(dep, 1);
return (error);
}
