/* $NetBSD: ext2fs_alloc.c,v 1.59 2025/06/27 19:55:38 andvar Exp $ */ /* * Copyright (c) 1982, 1986, 1989, 1993 * The Regents of the University of California. All rights reserved. * * 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. 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. * * @(#)ffs_alloc.c 8.11 (Berkeley) 10/27/94 * Modified for ext2fs by Manuel Bouyer. */ /* * Copyright (c) 1997 Manuel Bouyer. * * 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. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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. * * @(#)ffs_alloc.c 8.11 (Berkeley) 10/27/94 * Modified for ext2fs by Manuel Bouyer. */ #include __KERNEL_RCSID(0, "$NetBSD: ext2fs_alloc.c,v 1.59 2025/06/27 19:55:38 andvar Exp $"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include u_long ext2gennumber; static daddr_t ext2fs_alloccg(struct inode *, int, daddr_t, int); static u_long ext2fs_dirpref(struct m_ext2fs *); static void ext2fs_fserr(struct m_ext2fs *, u_int, const char *); static u_long ext2fs_hashalloc(struct inode *, int, long, int, daddr_t (*)(struct inode *, int, daddr_t, int)); static daddr_t ext2fs_nodealloccg(struct inode *, int, daddr_t, int); static daddr_t ext2fs_mapsearch(struct m_ext2fs *, char *, daddr_t); static __inline void ext2fs_cg_update(struct m_ext2fs *, int, struct ext2_gd *, int, int, int, daddr_t); static uint16_t ext2fs_cg_get_csum(struct m_ext2fs *, int, struct ext2_gd *); static void ext2fs_init_bb(struct m_ext2fs *, int, struct ext2_gd *, char *); /* * Allocate a block in the file system. * * A preference may be optionally specified. If a preference is given * the following hierarchy is used to allocate a block: * 1) allocate the requested block. * 2) allocate a rotationally optimal block in the same cylinder. * 3) allocate a block in the same cylinder group. * 4) quadratically rehash into other cylinder groups, until an * available block is located. * If no block preference is given the following hierarchy is used * to allocate a block: * 1) allocate a block in the cylinder group that contains the * inode for the file. * 2) quadratically rehash into other cylinder groups, until an * available block is located. */ int ext2fs_alloc(struct inode *ip, daddr_t lbn, daddr_t bpref, kauth_cred_t cred, daddr_t *bnp) { struct m_ext2fs *fs; daddr_t bno; int cg; *bnp = 0; fs = ip->i_e2fs; #ifdef DIAGNOSTIC if (cred == NOCRED) panic("ext2fs_alloc: missing credential"); #endif /* DIAGNOSTIC */ if (fs->e2fs.e2fs_fbcount == 0) goto nospace; if (kauth_authorize_system(cred, KAUTH_SYSTEM_FS_RESERVEDSPACE, 0, NULL, NULL, NULL) != 0 && freespace(fs) <= 0) goto nospace; if (bpref >= fs->e2fs.e2fs_bcount) bpref = 0; if (bpref == 0) cg = ino_to_cg(fs, ip->i_number); else cg = dtog(fs, bpref); bno = (daddr_t)ext2fs_hashalloc(ip, cg, bpref, fs->e2fs_bsize, ext2fs_alloccg); if (bno > 0) { ext2fs_setnblock(ip, ext2fs_nblock(ip) + btodb(fs->e2fs_bsize)); ip->i_flag |= IN_CHANGE | IN_UPDATE; *bnp = bno; return 0; } nospace: ext2fs_fserr(fs, kauth_cred_geteuid(cred), "file system full"); uprintf("\n%s: write failed, file system is full\n", fs->e2fs_fsmnt); return ENOSPC; } /* * Allocate an inode in the file system. * * If allocating a directory, use ext2fs_dirpref to select the inode. * If allocating in a directory, the following hierarchy is followed: * 1) allocate the preferred inode. * 2) allocate an inode in the same cylinder group. * 3) quadratically rehash into other cylinder groups, until an * available inode is located. * If no inode preference is given the following hierarchy is used * to allocate an inode: * 1) allocate an inode in cylinder group 0. * 2) quadratically rehash into other cylinder groups, until an * available inode is located. */ int ext2fs_valloc(struct vnode *pvp, int mode, kauth_cred_t cred, ino_t *inop) { struct inode *pip; struct m_ext2fs *fs; ino_t ino, ipref; int cg; pip = VTOI(pvp); fs = pip->i_e2fs; if (fs->e2fs.e2fs_ficount == 0) goto noinodes; if ((mode & IFMT) == IFDIR) cg = ext2fs_dirpref(fs); else cg = ino_to_cg(fs, pip->i_number); ipref = cg * fs->e2fs.e2fs_ipg + 1; ino = (ino_t)ext2fs_hashalloc(pip, cg, (long)ipref, mode, ext2fs_nodealloccg); if (ino == 0) goto noinodes; *inop = ino; return 0; noinodes: ext2fs_fserr(fs, kauth_cred_geteuid(cred), "out of inodes"); uprintf("\n%s: create/symlink failed, no inodes free\n", fs->e2fs_fsmnt); return ENOSPC; } /* * Find a cylinder to place a directory. * * The policy implemented by this algorithm is to select from * among those cylinder groups with above the average number of * free inodes, the one with the smallest number of directories. */ static u_long ext2fs_dirpref(struct m_ext2fs *fs) { int cg, maxspace, mincg, avgifree; avgifree = fs->e2fs.e2fs_ficount / fs->e2fs_ncg; maxspace = 0; mincg = -1; for (cg = 0; cg < fs->e2fs_ncg; cg++) { uint32_t nifree = (fs2h16(fs->e2fs_gd[cg].ext2bgd_nifree_hi) << 16) | fs2h16(fs->e2fs_gd[cg].ext2bgd_nifree); if (nifree < avgifree) { continue; } uint32_t nbfree = (fs2h16(fs->e2fs_gd[cg].ext2bgd_nbfree_hi) << 16) | fs2h16(fs->e2fs_gd[cg].ext2bgd_nbfree); if (mincg == -1 || nbfree > maxspace) { mincg = cg; maxspace = nbfree; } } return mincg; } /* * Select the desired position for the next block in a file. The file is * logically divided into sections. The first section is composed of the * direct blocks. Each additional section contains fs_maxbpg blocks. * * If no blocks have been allocated in the first section, the policy is to * request a block in the same cylinder group as the inode that describes * the file. Otherwise, the policy is to try to allocate the blocks * contiguously. The two fields of the ext2 inode extension (see * ufs/ufs/inode.h) help this. */ daddr_t ext2fs_blkpref(struct inode *ip, daddr_t lbn, int indx, int32_t *bap /* XXX ondisk32 */) { struct m_ext2fs *fs; int cg, i; fs = ip->i_e2fs; /* * if we are doing contiguous lbn allocation, try to alloc blocks * contiguously on disk */ if ( ip->i_e2fs_last_blk && lbn == ip->i_e2fs_last_lblk + 1) { return ip->i_e2fs_last_blk + 1; } /* * bap, if provided, gives us a list of blocks to which we want to * stay close */ if (bap) { for (i = indx; i >= 0 ; i--) { if (bap[i]) { return fs2h32(bap[i]) + 1; } } } /* fall back to the first block of the cylinder containing the inode */ cg = ino_to_cg(fs, ip->i_number); return fs->e2fs.e2fs_bpg * cg + fs->e2fs.e2fs_first_dblock + 1; } /* * Implement the cylinder overflow algorithm. * * The policy implemented by this algorithm is: * 1) allocate the block in its requested cylinder group. * 2) quadratically rehash on the cylinder group number. * 3) brute force search for a free block. */ static u_long ext2fs_hashalloc(struct inode *ip, int cg, long pref, int size, daddr_t (*allocator)(struct inode *, int, daddr_t, int)) { struct m_ext2fs *fs; long result; int i, icg = cg; fs = ip->i_e2fs; /* * 1: preferred cylinder group */ result = (*allocator)(ip, cg, pref, size); if (result) return result; /* * 2: quadratic rehash */ for (i = 1; i < fs->e2fs_ncg; i *= 2) { cg += i; if (cg >= fs->e2fs_ncg) cg -= fs->e2fs_ncg; result = (*allocator)(ip, cg, 0, size); if (result) return result; } /* * 3: brute force search * Note that we start at i == 2, since 0 was checked initially, * and 1 is always checked in the quadratic rehash. */ cg = (icg + 2) % fs->e2fs_ncg; for (i = 2; i < fs->e2fs_ncg; i++) { result = (*allocator)(ip, cg, 0, size); if (result) return result; cg++; if (cg == fs->e2fs_ncg) cg = 0; } return 0; } /* * Determine whether a block can be allocated. * * Check to see if a block of the appropriate size is available, * and if it is, allocate it. */ static daddr_t ext2fs_alloccg(struct inode *ip, int cg, daddr_t bpref, int size) { struct m_ext2fs *fs; char *bbp; struct buf *bp; int error, bno, start, end, loc; fs = ip->i_e2fs; if (fs->e2fs_gd[cg].ext2bgd_nbfree == 0 && fs->e2fs_gd[cg].ext2bgd_nbfree_hi == 0) return 0; error = bread(ip->i_devvp, EXT2_FSBTODB64(fs, fs2h32(fs->e2fs_gd[cg].ext2bgd_b_bitmap), fs2h32(fs->e2fs_gd[cg].ext2bgd_b_bitmap_hi)), (int)fs->e2fs_bsize, B_MODIFY, &bp); if (error) { return 0; } bbp = (char *)bp->b_data; if (dtog(fs, bpref) != cg) bpref = 0; /* initialize block bitmap now if uninit */ if (__predict_false(E2FS_HAS_GD_CSUM(fs) && (fs->e2fs_gd[cg].ext2bgd_flags & h2fs16(E2FS_BG_BLOCK_UNINIT)))) { ext2fs_init_bb(fs, cg, &fs->e2fs_gd[cg], bbp); fs->e2fs_gd[cg].ext2bgd_flags &= h2fs16(~E2FS_BG_BLOCK_UNINIT); } if (bpref != 0) { bpref = dtogd(fs, bpref); /* * if the requested block is available, use it */ if (isclr(bbp, bpref)) { bno = bpref; goto gotit; } } /* * no blocks in the requested cylinder, so take next * available one in this cylinder group. * first try to get 8 contiguous blocks, then fall back to a single * block. */ if (bpref) start = dtogd(fs, bpref) / NBBY; else start = 0; end = howmany(fs->e2fs.e2fs_fpg, NBBY) - start; for (loc = start; loc < end; loc++) { if (bbp[loc] == 0) { bno = loc * NBBY; goto gotit; } } for (loc = 0; loc < start; loc++) { if (bbp[loc] == 0) { bno = loc * NBBY; goto gotit; } } bno = ext2fs_mapsearch(fs, bbp, bpref); #if 0 /* * XXX jdolecek mapsearch actually never fails, it panics instead. * If re-enabling, make sure to brele() before returning. */ if (bno < 0) return 0; #endif gotit: #ifdef DIAGNOSTIC if (isset(bbp, (daddr_t)bno)) { printf("%s: cg=%d bno=%d fs=%s\n", __func__, cg, bno, fs->e2fs_fsmnt); panic("ext2fs_alloccg: dup alloc"); } #endif setbit(bbp, (daddr_t)bno); fs->e2fs.e2fs_fbcount--; ext2fs_cg_update(fs, cg, &fs->e2fs_gd[cg], -1, 0, 0, 0); fs->e2fs_fmod = 1; bdwrite(bp); return cg * fs->e2fs.e2fs_fpg + fs->e2fs.e2fs_first_dblock + bno; } /* * Determine whether an inode can be allocated. * * Check to see if an inode is available, and if it is, * allocate it using the following policy: * 1) allocate the requested inode. * 2) allocate the next available inode after the requested * inode in the specified cylinder group. */ static daddr_t ext2fs_nodealloccg(struct inode *ip, int cg, daddr_t ipref, int mode) { struct m_ext2fs *fs; char *ibp; struct buf *bp; int error, start, len, loc, map, i; ipref--; /* to avoid a lot of (ipref -1) */ if (ipref == -1) ipref = 0; fs = ip->i_e2fs; if (fs->e2fs_gd[cg].ext2bgd_nifree == 0 && fs->e2fs_gd[cg].ext2bgd_nifree_hi == 0) return 0; error = bread(ip->i_devvp, EXT2_FSBTODB64(fs, fs2h32(fs->e2fs_gd[cg].ext2bgd_i_bitmap), fs2h32(fs->e2fs_gd[cg].ext2bgd_i_bitmap_hi)), (int)fs->e2fs_bsize, B_MODIFY, &bp); if (error) { return 0; } ibp = (char *)bp->b_data; KASSERT(!E2FS_HAS_GD_CSUM(fs) || (fs->e2fs_gd[cg].ext2bgd_flags & h2fs16(E2FS_BG_INODE_ZEROED)) != 0); /* initialize inode bitmap now if uninit */ if (__predict_false(E2FS_HAS_GD_CSUM(fs) && (fs->e2fs_gd[cg].ext2bgd_flags & h2fs16(E2FS_BG_INODE_UNINIT)))) { KASSERT(fs2h16(fs->e2fs_gd[cg].ext2bgd_nifree) == fs->e2fs.e2fs_ipg); memset(ibp, 0, fs->e2fs_bsize); fs->e2fs_gd[cg].ext2bgd_flags &= h2fs16(~E2FS_BG_INODE_UNINIT); } if (ipref) { ipref %= fs->e2fs.e2fs_ipg; if (isclr(ibp, ipref)) goto gotit; } start = ipref / NBBY; len = howmany(fs->e2fs.e2fs_ipg - ipref, NBBY); loc = skpc(0xff, len, &ibp[start]); if (loc == 0) { len = start + 1; start = 0; loc = skpc(0xff, len, &ibp[0]); if (loc == 0) { printf("%s: cg = %d, ipref = %lld, fs = %s\n", __func__, cg, (long long)ipref, fs->e2fs_fsmnt); panic("%s: map corrupted", __func__); /* NOTREACHED */ } } i = start + len - loc; map = ibp[i] ^ 0xff; if (map == 0) { printf("%s: fs = %s\n", __func__, fs->e2fs_fsmnt); panic("%s: inode not in map", __func__); } ipref = i * NBBY + ffs(map) - 1; gotit: setbit(ibp, ipref); fs->e2fs.e2fs_ficount--; ext2fs_cg_update(fs, cg, &fs->e2fs_gd[cg], 0, -1, ((mode & IFMT) == IFDIR) ? 1 : 0, ipref); fs->e2fs_fmod = 1; bdwrite(bp); return cg * fs->e2fs.e2fs_ipg + ipref + 1; } /* * Free a block. * * The specified block is placed back in the * free map. */ void ext2fs_blkfree(struct inode *ip, daddr_t bno) { struct m_ext2fs *fs; char *bbp; struct buf *bp; int error, cg; fs = ip->i_e2fs; cg = dtog(fs, bno); KASSERT(!E2FS_HAS_GD_CSUM(fs) || (fs->e2fs_gd[cg].ext2bgd_flags & h2fs16(E2FS_BG_BLOCK_UNINIT)) == 0); if ((u_int)bno >= fs->e2fs.e2fs_bcount) { printf("%s: bad block %jd, ino %ju\n", __func__, (intmax_t)bno, (uintmax_t)ip->i_number); ext2fs_fserr(fs, ip->i_uid, "bad block"); return; } error = bread(ip->i_devvp, EXT2_FSBTODB64(fs, fs2h32(fs->e2fs_gd[cg].ext2bgd_b_bitmap), fs2h32(fs->e2fs_gd[cg].ext2bgd_b_bitmap_hi)), (int)fs->e2fs_bsize, B_MODIFY, &bp); if (error) { return; } bbp = (char *)bp->b_data; bno = dtogd(fs, bno); if (isclr(bbp, bno)) { printf("%s: dev = %#jx, block = %jd, fs = %s\n", __func__, (uintmax_t)ip->i_dev, (intmax_t)bno, fs->e2fs_fsmnt); panic("%s: freeing free block", __func__); } clrbit(bbp, bno); fs->e2fs.e2fs_fbcount++; ext2fs_cg_update(fs, cg, &fs->e2fs_gd[cg], 1, 0, 0, 0); fs->e2fs_fmod = 1; bdwrite(bp); } /* * Free an inode. * * The specified inode is placed back in the free map. */ int ext2fs_vfree(struct vnode *pvp, ino_t ino, int mode) { struct m_ext2fs *fs; char *ibp; struct inode *pip; struct buf *bp; int error, cg; pip = VTOI(pvp); fs = pip->i_e2fs; if ((u_int)ino > fs->e2fs.e2fs_icount || (u_int)ino < EXT2_FIRSTINO) panic("%s: range: dev = %#jx, ino = %ju, fs = %s", __func__, (uintmax_t)pip->i_dev, (uintmax_t)ino, fs->e2fs_fsmnt); cg = ino_to_cg(fs, ino); KASSERT(!E2FS_HAS_GD_CSUM(fs) || (fs->e2fs_gd[cg].ext2bgd_flags & h2fs16(E2FS_BG_INODE_UNINIT)) == 0); error = bread(pip->i_devvp, EXT2_FSBTODB64(fs, fs2h32(fs->e2fs_gd[cg].ext2bgd_i_bitmap), fs2h32(fs->e2fs_gd[cg].ext2bgd_i_bitmap_hi)), (int)fs->e2fs_bsize, B_MODIFY, &bp); if (error) { return 0; } ibp = (char *)bp->b_data; ino = (ino - 1) % fs->e2fs.e2fs_ipg; if (isclr(ibp, ino)) { printf("%s: dev = %#jx, ino = %ju, fs = %s\n", __func__, (uintmax_t)pip->i_dev, (uintmax_t)ino, fs->e2fs_fsmnt); if (fs->e2fs_ronly == 0) panic("%s: freeing free inode", __func__); } clrbit(ibp, ino); fs->e2fs.e2fs_ficount++; ext2fs_cg_update(fs, cg, &fs->e2fs_gd[cg], 0, 1, ((mode & IFMT) == IFDIR) ? -1 : 0, 0); fs->e2fs_fmod = 1; bdwrite(bp); return 0; } /* * Find a block in the specified cylinder group. * * It is a panic if a request is made to find a block if none are * available. */ static daddr_t ext2fs_mapsearch(struct m_ext2fs *fs, char *bbp, daddr_t bpref) { int start, len, loc, i, map; /* * find the fragment by searching through the free block * map for an appropriate bit pattern */ if (bpref) start = dtogd(fs, bpref) / NBBY; else start = 0; len = howmany(fs->e2fs.e2fs_fpg, NBBY) - start; loc = skpc(0xff, len, &bbp[start]); if (loc == 0) { len = start + 1; start = 0; loc = skpc(0xff, len, &bbp[start]); if (loc == 0) { printf("%s: start = %d, len = %d, fs = %s\n", __func__, start, len, fs->e2fs_fsmnt); panic("%s: map corrupted", __func__); /* NOTREACHED */ } } i = start + len - loc; map = bbp[i] ^ 0xff; if (map == 0) { printf("%s: fs = %s\n", __func__, fs->e2fs_fsmnt); panic("%s: block not in map", __func__); } return i * NBBY + ffs(map) - 1; } /* * Fserr prints the name of a file system with an error diagnostic. * * The form of the error message is: * fs: error message */ static void ext2fs_fserr(struct m_ext2fs *fs, u_int uid, const char *cp) { log(LOG_ERR, "uid %d on %s: %s\n", uid, fs->e2fs_fsmnt, cp); } static __inline void ext2fs_cg_update(struct m_ext2fs *fs, int cg, struct ext2_gd *gd, int nbfree, int nifree, int ndirs, daddr_t ioff) { if (nifree) { uint32_t ext2bgd_nifree = fs2h16(gd->ext2bgd_nifree) | (fs2h16(gd->ext2bgd_nifree_hi) << 16); ext2bgd_nifree += nifree; gd->ext2bgd_nifree = h2fs16(ext2bgd_nifree); gd->ext2bgd_nifree_hi = h2fs16(ext2bgd_nifree >> 16); /* * If we allocated inode on bigger offset than what was * ever used before, bump the itable_unused count. This * member only ever grows, and is used only for initialization * !INODE_ZEROED groups with used inodes. Of course, by the * time we get here the itables are already zeroed, but * e2fstools fsck.ext4 still checks this. */ if (E2FS_HAS_GD_CSUM(fs) && nifree < 0 && (ioff + 1) >= (fs->e2fs.e2fs_ipg - fs2h16(gd->ext2bgd_itable_unused_lo))) { gd->ext2bgd_itable_unused_lo = h2fs16(fs->e2fs.e2fs_ipg - (ioff + 1)); } KASSERT(!E2FS_HAS_GD_CSUM(fs) || gd->ext2bgd_itable_unused_lo <= ext2bgd_nifree); } if (nbfree) { uint32_t ext2bgd_nbfree = fs2h16(gd->ext2bgd_nbfree) | (fs2h16(gd->ext2bgd_nbfree_hi) << 16); ext2bgd_nbfree += nbfree; gd->ext2bgd_nbfree = h2fs16(ext2bgd_nbfree); gd->ext2bgd_nbfree_hi = h2fs16(ext2bgd_nbfree >> 16); } if (ndirs) { uint32_t ext2bgd_ndirs = fs2h16(gd->ext2bgd_ndirs) | (fs2h16(gd->ext2bgd_ndirs_hi) << 16); ext2bgd_ndirs += ndirs; gd->ext2bgd_ndirs = h2fs16(ext2bgd_ndirs); gd->ext2bgd_ndirs_hi = h2fs16(ext2bgd_ndirs >> 16); } if (E2FS_HAS_GD_CSUM(fs)) gd->ext2bgd_checksum = ext2fs_cg_get_csum(fs, cg, gd); } static const uint32_t ext2fs_crc32c_table[256] = { 0x00000000, 0xf26b8303, 0xe13b70f7, 0x1350f3f4, 0xc79a971f, 0x35f1141c, 0x26a1e7e8, 0xd4ca64eb, 0x8ad958cf, 0x78b2dbcc, 0x6be22838, 0x9989ab3b, 0x4d43cfd0, 0xbf284cd3, 0xac78bf27, 0x5e133c24, 0x105ec76f, 0xe235446c, 0xf165b798, 0x030e349b, 0xd7c45070, 0x25afd373, 0x36ff2087, 0xc494a384, 0x9a879fa0, 0x68ec1ca3, 0x7bbcef57, 0x89d76c54, 0x5d1d08bf, 0xaf768bbc, 0xbc267848, 0x4e4dfb4b, 0x20bd8ede, 0xd2d60ddd, 0xc186fe29, 0x33ed7d2a, 0xe72719c1, 0x154c9ac2, 0x061c6936, 0xf477ea35, 0xaa64d611, 0x580f5512, 0x4b5fa6e6, 0xb93425e5, 0x6dfe410e, 0x9f95c20d, 0x8cc531f9, 0x7eaeb2fa, 0x30e349b1, 0xc288cab2, 0xd1d83946, 0x23b3ba45, 0xf779deae, 0x05125dad, 0x1642ae59, 0xe4292d5a, 0xba3a117e, 0x4851927d, 0x5b016189, 0xa96ae28a, 0x7da08661, 0x8fcb0562, 0x9c9bf696, 0x6ef07595, 0x417b1dbc, 0xb3109ebf, 0xa0406d4b, 0x522bee48, 0x86e18aa3, 0x748a09a0, 0x67dafa54, 0x95b17957, 0xcba24573, 0x39c9c670, 0x2a993584, 0xd8f2b687, 0x0c38d26c, 0xfe53516f, 0xed03a29b, 0x1f682198, 0x5125dad3, 0xa34e59d0, 0xb01eaa24, 0x42752927, 0x96bf4dcc, 0x64d4cecf, 0x77843d3b, 0x85efbe38, 0xdbfc821c, 0x2997011f, 0x3ac7f2eb, 0xc8ac71e8, 0x1c661503, 0xee0d9600, 0xfd5d65f4, 0x0f36e6f7, 0x61c69362, 0x93ad1061, 0x80fde395, 0x72966096, 0xa65c047d, 0x5437877e, 0x4767748a, 0xb50cf789, 0xeb1fcbad, 0x197448ae, 0x0a24bb5a, 0xf84f3859, 0x2c855cb2, 0xdeeedfb1, 0xcdbe2c45, 0x3fd5af46, 0x7198540d, 0x83f3d70e, 0x90a324fa, 0x62c8a7f9, 0xb602c312, 0x44694011, 0x5739b3e5, 0xa55230e6, 0xfb410cc2, 0x092a8fc1, 0x1a7a7c35, 0xe811ff36, 0x3cdb9bdd, 0xceb018de, 0xdde0eb2a, 0x2f8b6829, 0x82f63b78, 0x709db87b, 0x63cd4b8f, 0x91a6c88c, 0x456cac67, 0xb7072f64, 0xa457dc90, 0x563c5f93, 0x082f63b7, 0xfa44e0b4, 0xe9141340, 0x1b7f9043, 0xcfb5f4a8, 0x3dde77ab, 0x2e8e845f, 0xdce5075c, 0x92a8fc17, 0x60c37f14, 0x73938ce0, 0x81f80fe3, 0x55326b08, 0xa759e80b, 0xb4091bff, 0x466298fc, 0x1871a4d8, 0xea1a27db, 0xf94ad42f, 0x0b21572c, 0xdfeb33c7, 0x2d80b0c4, 0x3ed04330, 0xccbbc033, 0xa24bb5a6, 0x502036a5, 0x4370c551, 0xb11b4652, 0x65d122b9, 0x97baa1ba, 0x84ea524e, 0x7681d14d, 0x2892ed69, 0xdaf96e6a, 0xc9a99d9e, 0x3bc21e9d, 0xef087a76, 0x1d63f975, 0x0e330a81, 0xfc588982, 0xb21572c9, 0x407ef1ca, 0x532e023e, 0xa145813d, 0x758fe5d6, 0x87e466d5, 0x94b49521, 0x66df1622, 0x38cc2a06, 0xcaa7a905, 0xd9f75af1, 0x2b9cd9f2, 0xff56bd19, 0x0d3d3e1a, 0x1e6dcdee, 0xec064eed, 0xc38d26c4, 0x31e6a5c7, 0x22b65633, 0xd0ddd530, 0x0417b1db, 0xf67c32d8, 0xe52cc12c, 0x1747422f, 0x49547e0b, 0xbb3ffd08, 0xa86f0efc, 0x5a048dff, 0x8ecee914, 0x7ca56a17, 0x6ff599e3, 0x9d9e1ae0, 0xd3d3e1ab, 0x21b862a8, 0x32e8915c, 0xc083125f, 0x144976b4, 0xe622f5b7, 0xf5720643, 0x07198540, 0x590ab964, 0xab613a67, 0xb831c993, 0x4a5a4a90, 0x9e902e7b, 0x6cfbad78, 0x7fab5e8c, 0x8dc0dd8f, 0xe330a81a, 0x115b2b19, 0x020bd8ed, 0xf0605bee, 0x24aa3f05, 0xd6c1bc06, 0xc5914ff2, 0x37faccf1, 0x69e9f0d5, 0x9b8273d6, 0x88d28022, 0x7ab90321, 0xae7367ca, 0x5c18e4c9, 0x4f48173d, 0xbd23943e, 0xf36e6f75, 0x0105ec76, 0x12551f82, 0xe03e9c81, 0x34f4f86a, 0xc69f7b69, 0xd5cf889d, 0x27a40b9e, 0x79b737ba, 0x8bdcb4b9, 0x988c474d, 0x6ae7c44e, 0xbe2da0a5, 0x4c4623a6, 0x5f16d052, 0xad7d5351, }; static uint32_t ext2fs_crc32c(uint32_t last, const void *vbuf, size_t len) { uint32_t crc = last; const uint8_t *buf = vbuf; while (len--) crc = ext2fs_crc32c_table[(crc ^ *buf++) & 0xff] ^ (crc >> 8); return crc; } /* * Compute group description csum. Structure data must be LE (not host). * Returned as LE (disk encoding). */ static uint16_t ext2fs_cg_get_csum(struct m_ext2fs *fs, int cg, struct ext2_gd *gd) { uint16_t crc; size_t cgsize = 1 << fs->e2fs_group_desc_shift; uint32_t cg_bswapped = h2fs32((uint32_t)cg); size_t off; if (EXT2F_HAS_ROCOMPAT_FEATURE(fs, EXT2F_ROCOMPAT_METADATA_CKSUM)) { uint32_t crc32; uint8_t dummy[2] = {0, 0}; off = offsetof(struct ext2_gd, ext2bgd_checksum); crc32 = ext2fs_crc32c(~0, fs->e2fs.e2fs_uuid, sizeof(fs->e2fs.e2fs_uuid)); crc32 = ext2fs_crc32c(crc32, &cg_bswapped, sizeof(cg_bswapped)); crc32 = ext2fs_crc32c(crc32, gd, off); crc32 = ext2fs_crc32c(crc32, dummy, 2); crc32 = ext2fs_crc32c(crc32, gd + off + 2, cgsize - (off + 2)); return h2fs16(crc32 & 0xffff); } if (!EXT2F_HAS_ROCOMPAT_FEATURE(fs, EXT2F_ROCOMPAT_GDT_CSUM)) return 0; off = offsetof(struct ext2_gd, ext2bgd_checksum); crc = crc16(~0, (uint8_t *)fs->e2fs.e2fs_uuid, sizeof(fs->e2fs.e2fs_uuid)); crc = crc16(crc, (uint8_t *)&cg_bswapped, sizeof(cg_bswapped)); crc = crc16(crc, (uint8_t *)gd, off); crc = crc16(crc, (uint8_t *)gd + off + 2, cgsize - (off + 2)); return h2fs16(crc); } static void ext2fs_init_bb(struct m_ext2fs *fs, int cg, struct ext2_gd *gd, char *bbp) { int i; memset(bbp, 0, fs->e2fs_bsize); /* * No block was ever allocated on this cg before, so the only used * blocks are metadata blocks on start of the group. We could optimize * this to set by bytes, but since this is done once per the group * in lifetime of filesystem, it really is not worth it. */ for(i=0; i < fs->e2fs.e2fs_bpg - fs2h16(gd->ext2bgd_nbfree); i++) setbit(bbp, i); } /* * Verify csum and initialize itable if not done already */ int ext2fs_cg_verify_and_initialize(struct vnode *devvp, struct m_ext2fs *fs, int ronly) { struct ext2_gd *gd; ino_t ioff; size_t boff; struct buf *bp; int cg, i, error; if (!E2FS_HAS_GD_CSUM(fs)) return 0; for(cg = 0; cg < fs->e2fs_ncg; cg++) { gd = &fs->e2fs_gd[cg]; /* Verify checksum */ uint16_t csum = ext2fs_cg_get_csum(fs, cg, gd); if (gd->ext2bgd_checksum != csum) { printf("%s: group %d invalid csum (%#x != %#x)\n", __func__, cg, gd->ext2bgd_checksum, csum); return EINVAL; } /* if mounting read-write, zero itable if not already done */ if (ronly || (gd->ext2bgd_flags & h2fs16(E2FS_BG_INODE_ZEROED)) != 0) continue; /* * We are skipping already used inodes, zero rest of itable * blocks. First block to zero could be only partial wipe, all * others are wiped completely. This might take a while, * there could be many inode table blocks. We use * delayed writes, so this shouldn't block for very * long. */ ioff = fs->e2fs.e2fs_ipg - fs2h16(gd->ext2bgd_itable_unused_lo); boff = (ioff % fs->e2fs_ipb) * EXT2_DINODE_SIZE(fs); for(i = ioff / fs->e2fs_ipb; i < fs->e2fs_itpg; i++) { if (boff) { /* partial wipe, must read old data */ error = bread(devvp, EXT2_FSBTODB64OFF(fs, fs2h32(gd->ext2bgd_i_tables), fs2h32(gd->ext2bgd_i_tables_hi), i), (int)fs->e2fs_bsize, B_MODIFY, &bp); if (error) { printf("%s: can't read itable block", __func__); return error; } memset((char *)bp->b_data + boff, 0, fs->e2fs_bsize - boff); boff = 0; } else { /* * Complete wipe, don't need to read data. This * assumes nothing else is changing the data. */ bp = getblk(devvp, EXT2_FSBTODB64OFF(fs, fs2h32(gd->ext2bgd_i_tables), fs2h32(gd->ext2bgd_i_tables_hi), i), (int)fs->e2fs_bsize, 0, 0); clrbuf(bp); } bdwrite(bp); } gd->ext2bgd_flags |= h2fs16(E2FS_BG_INODE_ZEROED); gd->ext2bgd_checksum = ext2fs_cg_get_csum(fs, cg, gd); fs->e2fs_fmod = 1; } return 0; }