/* * 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); }