/*
* If we have an FSInfo block, update it.
*/
static int
msdosfs_fsiflush(struct msdosfsmount *pmp, int waitfor)
{
struct fsinfo *fp;
struct buf *bp;
int error;
MSDOSFS_LOCK_MP(pmp);
if (pmp->pm_fsinfo == 0 || (pmp->pm_flags & MSDOSFS_FSIMOD) == 0) {
error = 0;
goto unlock;
}
error = bread(pmp->pm_devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec,
NOCRED, &bp);
if (error != 0) {
brelse(bp);
goto unlock;
}
fp = (struct fsinfo *)bp->b_data;
putulong(fp->fsinfree, pmp->pm_freeclustercount);
putulong(fp->fsinxtfree, pmp->pm_nxtfree);
pmp->pm_flags &= ~MSDOSFS_FSIMOD;
if (waitfor == MNT_WAIT)
error = bwrite(bp);
else
bawrite(bp);
unlock:
MSDOSFS_UNLOCK_MP(pmp);
return (error);
}
/* Map a 64-bit file number into a 32-bit one. */
uint32_t
msdosfs_fileno_map(struct mount *mp, uint64_t fileno)
{
struct msdosfsmount *pmp = VFSTOMSDOSFS(mp);
struct msdosfs_fileno key, *mf, *tmf;
uint32_t mapped;
if ((pmp->pm_flags & MSDOSFS_LARGEFS) == 0) {
KASSERT((uint32_t)fileno == fileno,
("fileno >32 bits but not a large fs?"));
return ((uint32_t)fileno);
}
if (fileno < FILENO_FIRST_DYN)
return ((uint32_t)fileno);
MSDOSFS_LOCK_MP(pmp);
key.mf_fileno64 = fileno;
mf = RB_FIND(msdosfs_filenotree, &pmp->pm_filenos, &key);
if (mf != NULL) {
mapped = mf->mf_fileno32;
MSDOSFS_UNLOCK_MP(pmp);
return (mapped);
}
if (pmp->pm_nfileno < FILENO_FIRST_DYN)
panic("msdosfs_fileno_map: wraparound");
MSDOSFS_UNLOCK_MP(pmp);
mf = malloc(sizeof(*mf), M_MSDOSFSFILENO, M_WAITOK);
MSDOSFS_LOCK_MP(pmp);
tmf = RB_FIND(msdosfs_filenotree, &pmp->pm_filenos, &key);
if (tmf != NULL) {
mapped = tmf->mf_fileno32;
MSDOSFS_UNLOCK_MP(pmp);
free(mf, M_MSDOSFSFILENO);
return (mapped);
}
mf->mf_fileno64 = fileno;
mapped = mf->mf_fileno32 = pmp->pm_nfileno++;
RB_INSERT(msdosfs_filenotree, &pmp->pm_filenos, mf);
MSDOSFS_UNLOCK_MP(pmp);
return (mapped);
}
static int
mountmsdosfs(struct vnode *devvp, struct mount *mp)
{
struct msdosfsmount *pmp;
struct buf *bp;
struct cdev *dev;
union bootsector *bsp;
struct byte_bpb33 *b33;
struct byte_bpb50 *b50;
struct byte_bpb710 *b710;
u_int8_t SecPerClust;
u_long clusters;
int ronly, error;
struct g_consumer *cp;
struct bufobj *bo;
bp = NULL; /* This and pmp both used in error_exit. */
pmp = NULL;
ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
dev = devvp->v_rdev;
dev_ref(dev);
DROP_GIANT();
g_topology_lock();
error = g_vfs_open(devvp, &cp, "msdosfs", ronly ? 0 : 1);
g_topology_unlock();
PICKUP_GIANT();
VOP_UNLOCK(devvp, 0);
if (error)
goto error_exit;
bo = &devvp->v_bufobj;
/*
* Read the boot sector of the filesystem, and then check the
* boot signature. If not a dos boot sector then error out.
*
* NOTE: 8192 is a magic size that works for ffs.
*/
error = bread(devvp, 0, 8192, NOCRED, &bp);
if (error)
goto error_exit;
bp->b_flags |= B_AGE;
bsp = (union bootsector *)bp->b_data;
b33 = (struct byte_bpb33 *)bsp->bs33.bsBPB;
b50 = (struct byte_bpb50 *)bsp->bs50.bsBPB;
b710 = (struct byte_bpb710 *)bsp->bs710.bsBPB;
#ifndef MSDOSFS_NOCHECKSIG
if (bsp->bs50.bsBootSectSig0 != BOOTSIG0
|| bsp->bs50.bsBootSectSig1 != BOOTSIG1) {
error = EINVAL;
goto error_exit;
}
#endif
pmp = malloc(sizeof *pmp, M_MSDOSFSMNT, M_WAITOK | M_ZERO);
pmp->pm_mountp = mp;
pmp->pm_cp = cp;
pmp->pm_bo = bo;
lockinit(&pmp->pm_fatlock, 0, msdosfs_lock_msg, 0, 0);
/*
* Initialize ownerships and permissions, since nothing else will
* initialize them iff we are mounting root.
*/
pmp->pm_uid = UID_ROOT;
pmp->pm_gid = GID_WHEEL;
pmp->pm_mask = pmp->pm_dirmask = S_IXUSR | S_IXGRP | S_IXOTH |
S_IRUSR | S_IRGRP | S_IROTH | S_IWUSR;
/*
* Experimental support for large MS-DOS filesystems.
* WARNING: This uses at least 32 bytes of kernel memory (which is not
* reclaimed until the FS is unmounted) for each file on disk to map
* between the 32-bit inode numbers used by VFS and the 64-bit
* pseudo-inode numbers used internally by msdosfs. This is only
* safe to use in certain controlled situations (e.g. read-only FS
* with less than 1 million files).
* Since the mappings do not persist across unmounts (or reboots), these
* filesystems are not suitable for exporting through NFS, or any other
* application that requires fixed inode numbers.
*/
vfs_flagopt(mp->mnt_optnew, "large", &pmp->pm_flags, MSDOSFS_LARGEFS);
/*
* Compute several useful quantities from the bpb in the
* bootsector. Copy in the dos 5 variant of the bpb then fix up
* the fields that are different between dos 5 and dos 3.3.
*/
SecPerClust = b50->bpbSecPerClust;
pmp->pm_BytesPerSec = getushort(b50->bpbBytesPerSec);
if (pmp->pm_BytesPerSec < DEV_BSIZE) {
error = EINVAL;
goto error_exit;
}
pmp->pm_ResSectors = getushort(b50->bpbResSectors);
pmp->pm_FATs = b50->bpbFATs;
pmp->pm_RootDirEnts = getushort(b50->bpbRootDirEnts);
pmp->pm_Sectors = getushort(b50->bpbSectors);
pmp->pm_FATsecs = getushort(b50->bpbFATsecs);
pmp->pm_SecPerTrack = getushort(b50->bpbSecPerTrack);
pmp->pm_Heads = getushort(b50->bpbHeads);
pmp->pm_Media = b50->bpbMedia;
/* calculate the ratio of sector size to DEV_BSIZE */
pmp->pm_BlkPerSec = pmp->pm_BytesPerSec / DEV_BSIZE;
/*
* We don't check pm_Heads nor pm_SecPerTrack, because
* these may not be set for EFI file systems. We don't
* use these anyway, so we're unaffected if they are
* invalid.
*/
if (!pmp->pm_BytesPerSec || !SecPerClust) {
error = EINVAL;
goto error_exit;
}
if (pmp->pm_Sectors == 0) {
pmp->pm_HiddenSects = getulong(b50->bpbHiddenSecs);
pmp->pm_HugeSectors = getulong(b50->bpbHugeSectors);
} else {
pmp->pm_HiddenSects = getushort(b33->bpbHiddenSecs);
pmp->pm_HugeSectors = pmp->pm_Sectors;
}
if (!(pmp->pm_flags & MSDOSFS_LARGEFS)) {
if (pmp->pm_HugeSectors > 0xffffffff /
(pmp->pm_BytesPerSec / sizeof(struct direntry)) + 1) {
/*
* We cannot deal currently with this size of disk
* due to fileid limitations (see msdosfs_getattr and
* msdosfs_readdir)
*/
error = EINVAL;
vfs_mount_error(mp,
"Disk too big, try '-o large' mount option");
goto error_exit;
}
}
if (pmp->pm_RootDirEnts == 0) {
if (pmp->pm_FATsecs
|| getushort(b710->bpbFSVers)) {
error = EINVAL;
#ifdef MSDOSFS_DEBUG
printf("mountmsdosfs(): bad FAT32 filesystem\n");
#endif
goto error_exit;
}
pmp->pm_fatmask = FAT32_MASK;
pmp->pm_fatmult = 4;
pmp->pm_fatdiv = 1;
pmp->pm_FATsecs = getulong(b710->bpbBigFATsecs);
if (getushort(b710->bpbExtFlags) & FATMIRROR)
pmp->pm_curfat = getushort(b710->bpbExtFlags) & FATNUM;
else
pmp->pm_flags |= MSDOSFS_FATMIRROR;
} else
pmp->pm_flags |= MSDOSFS_FATMIRROR;
/*
* Check a few values (could do some more):
* - logical sector size: power of 2, >= block size
* - sectors per cluster: power of 2, >= 1
* - number of sectors: >= 1, <= size of partition
* - number of FAT sectors: >= 1
*/
if ( (SecPerClust == 0)
|| (SecPerClust & (SecPerClust - 1))
|| (pmp->pm_BytesPerSec < DEV_BSIZE)
|| (pmp->pm_BytesPerSec & (pmp->pm_BytesPerSec - 1))
|| (pmp->pm_HugeSectors == 0)
|| (pmp->pm_FATsecs == 0)
|| (SecPerClust * pmp->pm_BlkPerSec > MAXBSIZE / DEV_BSIZE)
) {
error = EINVAL;
goto error_exit;
}
pmp->pm_HugeSectors *= pmp->pm_BlkPerSec;
pmp->pm_HiddenSects *= pmp->pm_BlkPerSec; /* XXX not used? */
pmp->pm_FATsecs *= pmp->pm_BlkPerSec;
SecPerClust *= pmp->pm_BlkPerSec;
pmp->pm_fatblk = pmp->pm_ResSectors * pmp->pm_BlkPerSec;
if (FAT32(pmp)) {
pmp->pm_rootdirblk = getulong(b710->bpbRootClust);
pmp->pm_firstcluster = pmp->pm_fatblk
+ (pmp->pm_FATs * pmp->pm_FATsecs);
pmp->pm_fsinfo = getushort(b710->bpbFSInfo) * pmp->pm_BlkPerSec;
} else {
pmp->pm_rootdirblk = pmp->pm_fatblk +
(pmp->pm_FATs * pmp->pm_FATsecs);
pmp->pm_rootdirsize = howmany(pmp->pm_RootDirEnts *
sizeof(struct direntry), DEV_BSIZE); /* in blocks */
pmp->pm_firstcluster = pmp->pm_rootdirblk + pmp->pm_rootdirsize;
}
pmp->pm_maxcluster = (pmp->pm_HugeSectors - pmp->pm_firstcluster) /
SecPerClust + 1;
pmp->pm_fatsize = pmp->pm_FATsecs * DEV_BSIZE; /* XXX not used? */
if (pmp->pm_fatmask == 0) {
if (pmp->pm_maxcluster
<= ((CLUST_RSRVD - CLUST_FIRST) & FAT12_MASK)) {
/*
* This will usually be a floppy disk. This size makes
* sure that one fat entry will not be split across
* multiple blocks.
*/
pmp->pm_fatmask = FAT12_MASK;
pmp->pm_fatmult = 3;
pmp->pm_fatdiv = 2;
} else {
pmp->pm_fatmask = FAT16_MASK;
pmp->pm_fatmult = 2;
pmp->pm_fatdiv = 1;
}
}
clusters = (pmp->pm_fatsize / pmp->pm_fatmult) * pmp->pm_fatdiv;
if (pmp->pm_maxcluster >= clusters) {
#ifdef MSDOSFS_DEBUG
printf("Warning: number of clusters (%ld) exceeds FAT "
"capacity (%ld)\n", pmp->pm_maxcluster + 1, clusters);
#endif
pmp->pm_maxcluster = clusters - 1;
}
if (FAT12(pmp))
pmp->pm_fatblocksize = 3 * 512;
else
pmp->pm_fatblocksize = PAGE_SIZE;
pmp->pm_fatblocksize = roundup(pmp->pm_fatblocksize,
pmp->pm_BytesPerSec);
pmp->pm_fatblocksec = pmp->pm_fatblocksize / DEV_BSIZE;
pmp->pm_bnshift = ffs(DEV_BSIZE) - 1;
/*
* Compute mask and shift value for isolating cluster relative byte
* offsets and cluster numbers from a file offset.
*/
pmp->pm_bpcluster = SecPerClust * DEV_BSIZE;
pmp->pm_crbomask = pmp->pm_bpcluster - 1;
pmp->pm_cnshift = ffs(pmp->pm_bpcluster) - 1;
/*
* Check for valid cluster size
* must be a power of 2
*/
if (pmp->pm_bpcluster ^ (1 << pmp->pm_cnshift)) {
error = EINVAL;
goto error_exit;
}
/*
* Release the bootsector buffer.
*/
brelse(bp);
bp = NULL;
/*
* Check the fsinfo sector if we have one. Silently fix up our
* in-core copy of fp->fsinxtfree if it is unknown (0xffffffff)
* or too large. Ignore fp->fsinfree for now, since we need to
* read the entire FAT anyway to fill the inuse map.
*/
if (pmp->pm_fsinfo) {
struct fsinfo *fp;
if ((error = bread(devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec,
NOCRED, &bp)) != 0)
goto error_exit;
fp = (struct fsinfo *)bp->b_data;
if (!bcmp(fp->fsisig1, "RRaA", 4)
&& !bcmp(fp->fsisig2, "rrAa", 4)
&& !bcmp(fp->fsisig3, "\0\0\125\252", 4)) {
pmp->pm_nxtfree = getulong(fp->fsinxtfree);
if (pmp->pm_nxtfree > pmp->pm_maxcluster)
pmp->pm_nxtfree = CLUST_FIRST;
} else
pmp->pm_fsinfo = 0;
brelse(bp);
bp = NULL;
}
/*
* Finish initializing pmp->pm_nxtfree (just in case the first few
* sectors aren't properly reserved in the FAT). This completes
* the fixup for fp->fsinxtfree, and fixes up the zero-initialized
* value if there is no fsinfo. We will use pmp->pm_nxtfree
* internally even if there is no fsinfo.
*/
if (pmp->pm_nxtfree < CLUST_FIRST)
pmp->pm_nxtfree = CLUST_FIRST;
/*
* Allocate memory for the bitmap of allocated clusters, and then
* fill it in.
*/
pmp->pm_inusemap = malloc(howmany(pmp->pm_maxcluster + 1, N_INUSEBITS)
* sizeof(*pmp->pm_inusemap),
M_MSDOSFSFAT, M_WAITOK);
/*
* fillinusemap() needs pm_devvp.
*/
pmp->pm_devvp = devvp;
pmp->pm_dev = dev;
/*
* Have the inuse map filled in.
*/
MSDOSFS_LOCK_MP(pmp);
error = fillinusemap(pmp);
MSDOSFS_UNLOCK_MP(pmp);
if (error != 0)
goto error_exit;
/*
* If they want fat updates to be synchronous then let them suffer
* the performance degradation in exchange for the on disk copy of
* the fat being correct just about all the time. I suppose this
* would be a good thing to turn on if the kernel is still flakey.
*/
if (mp->mnt_flag & MNT_SYNCHRONOUS)
pmp->pm_flags |= MSDOSFSMNT_WAITONFAT;
/*
* Finish up.
*/
if (ronly)
pmp->pm_flags |= MSDOSFSMNT_RONLY;
else {
if ((error = markvoldirty(pmp, 1)) != 0) {
(void)markvoldirty(pmp, 0);
goto error_exit;
}
pmp->pm_fmod = 1;
}
mp->mnt_data = pmp;
mp->mnt_stat.f_fsid.val[0] = dev2udev(dev);
mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum;
MNT_ILOCK(mp);
mp->mnt_flag |= MNT_LOCAL;
mp->mnt_kern_flag |= MNTK_USES_BCACHE;
MNT_IUNLOCK(mp);
if (pmp->pm_flags & MSDOSFS_LARGEFS)
msdosfs_fileno_init(mp);
return 0;
error_exit:
if (bp)
brelse(bp);
if (cp != NULL) {
DROP_GIANT();
g_topology_lock();
g_vfs_close(cp);
g_topology_unlock();
PICKUP_GIANT();
}
if (pmp) {
lockdestroy(&pmp->pm_fatlock);
if (pmp->pm_inusemap)
free(pmp->pm_inusemap, M_MSDOSFSFAT);
free(pmp, M_MSDOSFSMNT);
mp->mnt_data = NULL;
}
dev_rel(dev);
return (error);
}
