/* * Select the desired position for the next block in a file. * * we try to mimic what Remy does in inode_getblk/block_getblk * * we note: blocknr == 0 means that we're about to allocate either * a direct block or a pointer block at the first level of indirection * (In other words, stuff that will go in i_db[] or i_ib[]) * * blocknr != 0 means that we're allocating a block that is none * of the above. Then, blocknr tells us the number of the block * that will hold the pointer */ e4fs_daddr_t ext2_blkpref(struct inode *ip, e2fs_lbn_t lbn, int indx, e2fs_daddr_t *bap, e2fs_daddr_t blocknr) { int tmp; mtx_assert(EXT2_MTX(ip->i_ump), MA_OWNED); /* if the next block is actually what we thought it is, then set the goal to what we thought it should be */ if (ip->i_next_alloc_block == lbn && ip->i_next_alloc_goal != 0) return ip->i_next_alloc_goal; /* now check whether we were provided with an array that basically tells us previous blocks to which we want to stay closeby */ if (bap) for (tmp = indx - 1; tmp >= 0; tmp--) if (bap[tmp]) return bap[tmp]; /* else let's fall back to the blocknr, or, if there is none, follow the rule that a block should be allocated near its inode */ return blocknr ? blocknr : (e2fs_daddr_t)(ip->i_block_group * EXT2_BLOCKS_PER_GROUP(ip->i_e2fs)) + ip->i_e2fs->e2fs->e2fs_first_dblock; }
/* * Allocate a block in the filesystem. * * 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) quadradically 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) quadradically rehash into other cylinder groups, until an * available block is located. */ int ext2_alloc(struct inode *ip, daddr_t lbn, e4fs_daddr_t bpref, int size, struct ucred *cred, e4fs_daddr_t *bnp) { struct m_ext2fs *fs; struct ext2mount *ump; int32_t bno; int cg; *bnp = 0; fs = ip->i_e2fs; ump = ip->i_ump; mtx_assert(EXT2_MTX(ump), MA_OWNED); #ifdef INVARIANTS if ((u_int)size > fs->e2fs_bsize || blkoff(fs, size) != 0) { vn_printf(ip->i_devvp, "bsize = %lu, size = %d, fs = %s\n", (long unsigned int)fs->e2fs_bsize, size, fs->e2fs_fsmnt); panic("ext2_alloc: bad size"); } if (cred == NOCRED) panic("ext2_alloc: missing credential"); #endif /* INVARIANTS */ if (size == fs->e2fs_bsize && fs->e2fs->e2fs_fbcount == 0) goto nospace; if (cred->cr_uid != 0 && fs->e2fs->e2fs_fbcount < fs->e2fs->e2fs_rbcount) 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)ext2_hashalloc(ip, cg, bpref, fs->e2fs_bsize, ext2_alloccg); if (bno > 0) { /* set next_alloc fields as done in block_getblk */ ip->i_next_alloc_block = lbn; ip->i_next_alloc_goal = bno; ip->i_blocks += btodb(fs->e2fs_bsize); ip->i_flag |= IN_CHANGE | IN_UPDATE; *bnp = bno; return (0); } nospace: EXT2_UNLOCK(ump); ext2_fserr(fs, cred->cr_uid, "filesystem full"); uprintf("\n%s: write failed, filesystem is full\n", fs->e2fs_fsmnt); return (ENOSPC); }
/* * Implement the cylinder overflow algorithm. * * The policy implemented by this algorithm is: * 1) allocate the block in its requested cylinder group. * 2) quadradically rehash on the cylinder group number. * 3) brute force search for a free block. */ static u_long ext2_hashalloc(struct inode *ip, int cg, long pref, int size, daddr_t (*allocator)(struct inode *, int, daddr_t, int)) { struct m_ext2fs *fs; ino_t result; int i, icg = cg; mtx_assert(EXT2_MTX(ip->i_ump), MA_OWNED); 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_gcount; i *= 2) { cg += i; if (cg >= fs->e2fs_gcount) cg -= fs->e2fs_gcount; 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_gcount; for (i = 2; i < fs->e2fs_gcount; i++) { result = (*allocator)(ip, cg, 0, size); if (result) return (result); cg++; if (cg == fs->e2fs_gcount) cg = 0; } return (0); }
/* * Common code for mount and mountroot. */ static int ext2_mountfs(struct vnode *devvp, struct mount *mp) { struct ext2mount *ump; struct buf *bp; struct m_ext2fs *fs; struct ext2fs *es; struct cdev *dev = devvp->v_rdev; struct g_consumer *cp; struct bufobj *bo; struct csum *sump; int error; int ronly; int i, size; int32_t *lp; ronly = vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0); /* XXX: use VOP_ACESS to check FS perms */ DROP_GIANT(); g_topology_lock(); error = g_vfs_open(devvp, &cp, "ext2fs", ronly ? 0 : 1); g_topology_unlock(); PICKUP_GIANT(); VOP_UNLOCK(devvp, 0); if (error) return (error); /* XXX: should we check for some sectorsize or 512 instead? */ if (((SBSIZE % cp->provider->sectorsize) != 0) || (SBSIZE < cp->provider->sectorsize)) { DROP_GIANT(); g_topology_lock(); g_vfs_close(cp); g_topology_unlock(); PICKUP_GIANT(); return (EINVAL); } bo = &devvp->v_bufobj; bo->bo_private = cp; bo->bo_ops = g_vfs_bufops; if (devvp->v_rdev->si_iosize_max != 0) mp->mnt_iosize_max = devvp->v_rdev->si_iosize_max; if (mp->mnt_iosize_max > MAXPHYS) mp->mnt_iosize_max = MAXPHYS; bp = NULL; ump = NULL; if ((error = bread(devvp, SBLOCK, SBSIZE, NOCRED, &bp)) != 0) goto out; es = (struct ext2fs *)bp->b_data; if (ext2_check_sb_compat(es, dev, ronly) != 0) { error = EINVAL; /* XXX needs translation */ goto out; } if ((es->e2fs_state & E2FS_ISCLEAN) == 0 || (es->e2fs_state & E2FS_ERRORS)) { if (ronly || (mp->mnt_flag & MNT_FORCE)) { printf( "WARNING: Filesystem was not properly dismounted\n"); } else { printf( "WARNING: R/W mount denied. Filesystem is not clean - run fsck\n"); error = EPERM; goto out; } } ump = malloc(sizeof(*ump), M_EXT2MNT, M_WAITOK | M_ZERO); /* * I don't know whether this is the right strategy. Note that * we dynamically allocate both an ext2_sb_info and an ext2_super_block * while Linux keeps the super block in a locked buffer. */ ump->um_e2fs = malloc(sizeof(struct m_ext2fs), M_EXT2MNT, M_WAITOK); ump->um_e2fs->e2fs = malloc(sizeof(struct ext2fs), M_EXT2MNT, M_WAITOK); mtx_init(EXT2_MTX(ump), "EXT2FS", "EXT2FS Lock", MTX_DEF); bcopy(es, ump->um_e2fs->e2fs, (u_int)sizeof(struct ext2fs)); if ((error = compute_sb_data(devvp, ump->um_e2fs->e2fs, ump->um_e2fs))) goto out; /* * Calculate the maximum contiguous blocks and size of cluster summary * array. In FFS this is done by newfs; however, the superblock * in ext2fs doesn't have these variables, so we can calculate * them here. */ ump->um_e2fs->e2fs_maxcontig = MAX(1, MAXPHYS / ump->um_e2fs->e2fs_bsize); if (ump->um_e2fs->e2fs_maxcontig > 0) ump->um_e2fs->e2fs_contigsumsize = MIN(ump->um_e2fs->e2fs_maxcontig, EXT2_MAXCONTIG); else ump->um_e2fs->e2fs_contigsumsize = 0; if (ump->um_e2fs->e2fs_contigsumsize > 0) { size = ump->um_e2fs->e2fs_gcount * sizeof(int32_t); ump->um_e2fs->e2fs_maxcluster = malloc(size, M_EXT2MNT, M_WAITOK); size = ump->um_e2fs->e2fs_gcount * sizeof(struct csum); ump->um_e2fs->e2fs_clustersum = malloc(size, M_EXT2MNT, M_WAITOK); lp = ump->um_e2fs->e2fs_maxcluster; sump = ump->um_e2fs->e2fs_clustersum; for (i = 0; i < ump->um_e2fs->e2fs_gcount; i++, sump++) { *lp++ = ump->um_e2fs->e2fs_contigsumsize; sump->cs_init = 0; sump->cs_sum = malloc((ump->um_e2fs->e2fs_contigsumsize + 1) * sizeof(int32_t), M_EXT2MNT, M_WAITOK | M_ZERO); } } brelse(bp); bp = NULL; fs = ump->um_e2fs; fs->e2fs_ronly = ronly; /* ronly is set according to mnt_flags */ /* * If the fs is not mounted read-only, make sure the super block is * always written back on a sync(). */ fs->e2fs_wasvalid = fs->e2fs->e2fs_state & E2FS_ISCLEAN ? 1 : 0; if (ronly == 0) { fs->e2fs_fmod = 1; /* mark it modified */ fs->e2fs->e2fs_state &= ~E2FS_ISCLEAN; /* set fs invalid */ } mp->mnt_data = ump; mp->mnt_stat.f_fsid.val[0] = dev2udev(dev); mp->mnt_stat.f_fsid.val[1] = mp->mnt_vfc->vfc_typenum; mp->mnt_maxsymlinklen = EXT2_MAXSYMLINKLEN; MNT_ILOCK(mp); mp->mnt_flag |= MNT_LOCAL; MNT_IUNLOCK(mp); ump->um_mountp = mp; ump->um_dev = dev; ump->um_devvp = devvp; ump->um_bo = &devvp->v_bufobj; ump->um_cp = cp; /* * Setting those two parameters allowed us to use * ufs_bmap w/o changse! */ ump->um_nindir = EXT2_ADDR_PER_BLOCK(fs); ump->um_bptrtodb = fs->e2fs->e2fs_log_bsize + 1; ump->um_seqinc = EXT2_FRAGS_PER_BLOCK(fs); if (ronly == 0) ext2_sbupdate(ump, MNT_WAIT); /* * Initialize filesystem stat information in mount struct. */ MNT_ILOCK(mp); mp->mnt_kern_flag |= MNTK_MPSAFE | MNTK_LOOKUP_SHARED | MNTK_EXTENDED_SHARED; MNT_IUNLOCK(mp); return (0); out: if (bp) brelse(bp); if (cp != NULL) { DROP_GIANT(); g_topology_lock(); g_vfs_close(cp); g_topology_unlock(); PICKUP_GIANT(); } if (ump) { mtx_destroy(EXT2_MTX(ump)); free(ump->um_e2fs->e2fs_gd, M_EXT2MNT); free(ump->um_e2fs->e2fs_contigdirs, M_EXT2MNT); free(ump->um_e2fs->e2fs, M_EXT2MNT); free(ump->um_e2fs, M_EXT2MNT); free(ump, M_EXT2MNT); mp->mnt_data = NULL; } return (error); }
/* * Find a cylinder to place a directory. * * The policy implemented by this algorithm is to allocate a * directory inode in the same cylinder group as its parent * directory, but also to reserve space for its files inodes * and data. Restrict the number of directories which may be * allocated one after another in the same cylinder group * without intervening allocation of files. * * If we allocate a first level directory then force allocation * in another cylinder group. * */ static u_long ext2_dirpref(struct inode *pip) { struct m_ext2fs *fs; int cg, prefcg, cgsize; u_int avgifree, avgbfree, avgndir, curdirsize; u_int minifree, minbfree, maxndir; u_int mincg, minndir; u_int dirsize, maxcontigdirs; mtx_assert(EXT2_MTX(pip->i_ump), MA_OWNED); fs = pip->i_e2fs; avgifree = fs->e2fs->e2fs_ficount / fs->e2fs_gcount; avgbfree = fs->e2fs->e2fs_fbcount / fs->e2fs_gcount; avgndir = fs->e2fs_total_dir / fs->e2fs_gcount; /* * Force allocation in another cg if creating a first level dir. */ ASSERT_VOP_LOCKED(ITOV(pip), "ext2fs_dirpref"); if (ITOV(pip)->v_vflag & VV_ROOT) { prefcg = arc4random() % fs->e2fs_gcount; mincg = prefcg; minndir = fs->e2fs_ipg; for (cg = prefcg; cg < fs->e2fs_gcount; cg++) if (fs->e2fs_gd[cg].ext2bgd_ndirs < minndir && fs->e2fs_gd[cg].ext2bgd_nifree >= avgifree && fs->e2fs_gd[cg].ext2bgd_nbfree >= avgbfree) { mincg = cg; minndir = fs->e2fs_gd[cg].ext2bgd_ndirs; } for (cg = 0; cg < prefcg; cg++) if (fs->e2fs_gd[cg].ext2bgd_ndirs < minndir && fs->e2fs_gd[cg].ext2bgd_nifree >= avgifree && fs->e2fs_gd[cg].ext2bgd_nbfree >= avgbfree) { mincg = cg; minndir = fs->e2fs_gd[cg].ext2bgd_ndirs; } return (mincg); } /* * Count various limits which used for * optimal allocation of a directory inode. */ maxndir = min(avgndir + fs->e2fs_ipg / 16, fs->e2fs_ipg); minifree = avgifree - avgifree / 4; if (minifree < 1) minifree = 1; minbfree = avgbfree - avgbfree / 4; if (minbfree < 1) minbfree = 1; cgsize = fs->e2fs_fsize * fs->e2fs_fpg; dirsize = AVGDIRSIZE; curdirsize = avgndir ? (cgsize - avgbfree * fs->e2fs_bsize) / avgndir : 0; if (dirsize < curdirsize) dirsize = curdirsize; maxcontigdirs = min((avgbfree * fs->e2fs_bsize) / dirsize, 255); maxcontigdirs = min(maxcontigdirs, fs->e2fs_ipg / AFPDIR); if (maxcontigdirs == 0) maxcontigdirs = 1; /* * Limit number of dirs in one cg and reserve space for * regular files, but only if we have no deficit in * inodes or space. */ prefcg = ino_to_cg(fs, pip->i_number); for (cg = prefcg; cg < fs->e2fs_gcount; cg++) if (fs->e2fs_gd[cg].ext2bgd_ndirs < maxndir && fs->e2fs_gd[cg].ext2bgd_nifree >= minifree && fs->e2fs_gd[cg].ext2bgd_nbfree >= minbfree) { if (fs->e2fs_contigdirs[cg] < maxcontigdirs) return (cg); } for (cg = 0; cg < prefcg; cg++) if (fs->e2fs_gd[cg].ext2bgd_ndirs < maxndir && fs->e2fs_gd[cg].ext2bgd_nifree >= minifree && fs->e2fs_gd[cg].ext2bgd_nbfree >= minbfree) { if (fs->e2fs_contigdirs[cg] < maxcontigdirs) return (cg); } /* * This is a backstop when we have deficit in space. */ for (cg = prefcg; cg < fs->e2fs_gcount; cg++) if (fs->e2fs_gd[cg].ext2bgd_nifree >= avgifree) return (cg); for (cg = 0; cg < prefcg; cg++) if (fs->e2fs_gd[cg].ext2bgd_nifree >= avgifree) break; return (cg); }