[thirdparty/e2fsprogs.git] / lib / ext2fs / initialize.c

/*
 * initialize.c --- initialize a filesystem handle given superblock
 *      parameters.  Used by mke2fs when initializing a filesystem.
 *
 * Copyright (C) 1994, 1995, 1996 Theodore Ts'o.
 *
 * %Begin-Header%
 * This file may be redistributed under the terms of the GNU Library
 * General Public License, version 2.
 * %End-Header%
 */

#include "config.h"
#include <stdio.h>
#include <string.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <fcntl.h>
#include <time.h>
#if HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif

#include "ext2_fs.h"
#include "ext2fs.h"

#if defined(__linux__)    &&    defined(EXT2_OS_LINUX)
#define CREATOR_OS EXT2_OS_LINUX
#else
#if defined(__GNU__)     &&     defined(EXT2_OS_HURD)
#define CREATOR_OS EXT2_OS_HURD
#else
#if defined(__FreeBSD__) &&     defined(EXT2_OS_FREEBSD)
#define CREATOR_OS EXT2_OS_FREEBSD
#else
#if defined(LITES)         &&   defined(EXT2_OS_LITES)
#define CREATOR_OS EXT2_OS_LITES
#else
#define CREATOR_OS EXT2_OS_LINUX /* by default */
#endif /* defined(LITES) && defined(EXT2_OS_LITES) */
#endif /* defined(__FreeBSD__) && defined(EXT2_OS_FREEBSD) */
#endif /* defined(__GNU__)     && defined(EXT2_OS_HURD) */
#endif /* defined(__linux__)   && defined(EXT2_OS_LINUX) */

/*
 * Calculate the number of GDT blocks to reserve for online filesystem growth.
 * The absolute maximum number of GDT blocks we can reserve is determined by
 * the number of block pointers that can fit into a single block.
 */
static unsigned int calc_reserved_gdt_blocks(ext2_filsys fs)
{
        struct ext2_super_block *sb = fs->super;
        unsigned long bpg = sb->s_blocks_per_group;
        unsigned int gdpb = EXT2_DESC_PER_BLOCK(sb);
        unsigned long max_blocks = 0xffffffff;
        unsigned long rsv_groups;
        unsigned int rsv_gdb;

        /* We set it at 1024x the current filesystem size, or
         * the upper block count limit (2^32), whichever is lower.
         */
        if (ext2fs_blocks_count(sb) < max_blocks / 1024)
                max_blocks = ext2fs_blocks_count(sb) * 1024;
        /*
         * ext2fs_div64_ceil() is unnecessary because max_blocks is
         * max _GDT_ blocks, which is limited to 32 bits.
         */
        rsv_groups = ext2fs_div_ceil(max_blocks - sb->s_first_data_block, bpg);
        rsv_gdb = ext2fs_div_ceil(rsv_groups, gdpb) - fs->desc_blocks;
        if (rsv_gdb > EXT2_ADDR_PER_BLOCK(sb))
                rsv_gdb = EXT2_ADDR_PER_BLOCK(sb);
#ifdef RES_GDT_DEBUG
        printf("max_blocks %lu, rsv_groups = %lu, rsv_gdb = %u\n",
               max_blocks, rsv_groups, rsv_gdb);
#endif

        return rsv_gdb;
}

errcode_t ext2fs_initialize(const char *name, int flags,
                            struct ext2_super_block *param,
                            io_manager manager, ext2_filsys *ret_fs)
{
        ext2_filsys     fs;
        errcode_t       retval;
        struct ext2_super_block *super;
        unsigned int    rem;
        unsigned int    overhead = 0;
        unsigned int    ipg;
        dgrp_t          i;
        blk64_t         free_blocks;
        blk_t           numblocks;
        int             rsv_gdt;
        int             csum_flag;
        int             bigalloc_flag;
        int             io_flags;
        unsigned        reserved_inos;
        char            *buf = 0;
        char            c;
        double          reserved_ratio;

        if (!param || !ext2fs_blocks_count(param))
                return EXT2_ET_INVALID_ARGUMENT;

        retval = ext2fs_get_mem(sizeof(struct struct_ext2_filsys), &fs);
        if (retval)
                return retval;

        memset(fs, 0, sizeof(struct struct_ext2_filsys));
        fs->magic = EXT2_ET_MAGIC_EXT2FS_FILSYS;
        fs->flags = flags | EXT2_FLAG_RW;
        fs->umask = 022;
        fs->default_bitmap_type = EXT2FS_BMAP64_RBTREE;
#ifdef WORDS_BIGENDIAN
        fs->flags |= EXT2_FLAG_SWAP_BYTES;
#endif
        io_flags = IO_FLAG_RW;
        if (flags & EXT2_FLAG_EXCLUSIVE)
                io_flags |= IO_FLAG_EXCLUSIVE;
        if (flags & EXT2_FLAG_DIRECT_IO)
                io_flags |= IO_FLAG_DIRECT_IO;
        retval = manager->open(name, io_flags, &fs->io);
        if (retval)
                goto cleanup;
        fs->image_io = fs->io;
        fs->io->app_data = fs;
        retval = ext2fs_get_mem(strlen(name)+1, &fs->device_name);
        if (retval)
                goto cleanup;

        strcpy(fs->device_name, name);
        retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &super);
        if (retval)
                goto cleanup;
        fs->super = super;

        memset(super, 0, SUPERBLOCK_SIZE);

#define set_field(field, default) (super->field = param->field ? \
                                   param->field : (default))
#define assign_field(field)     (super->field = param->field)

        super->s_magic = EXT2_SUPER_MAGIC;
        super->s_state = EXT2_VALID_FS;

        bigalloc_flag = ext2fs_has_feature_bigalloc(param);

        assign_field(s_log_block_size);

        if (bigalloc_flag) {
                set_field(s_log_cluster_size, super->s_log_block_size+4);
                if (super->s_log_block_size > super->s_log_cluster_size) {
                        retval = EXT2_ET_INVALID_ARGUMENT;
                        goto cleanup;
                }
        } else
                super->s_log_cluster_size = super->s_log_block_size;

        set_field(s_first_data_block, super->s_log_cluster_size ? 0 : 1);
        set_field(s_max_mnt_count, 0);
        set_field(s_errors, EXT2_ERRORS_DEFAULT);
        set_field(s_feature_compat, 0);
        set_field(s_feature_incompat, 0);
        set_field(s_feature_ro_compat, 0);
        set_field(s_default_mount_opts, 0);
        set_field(s_first_meta_bg, 0);
        set_field(s_raid_stride, 0);            /* default stride size: 0 */
        set_field(s_raid_stripe_width, 0);      /* default stripe width: 0 */
        set_field(s_log_groups_per_flex, 0);
        set_field(s_flags, 0);
        assign_field(s_backup_bgs[0]);
        assign_field(s_backup_bgs[1]);
        if (super->s_feature_incompat & ~EXT2_LIB_FEATURE_INCOMPAT_SUPP) {
                retval = EXT2_ET_UNSUPP_FEATURE;
                goto cleanup;
        }
        if (super->s_feature_ro_compat & ~EXT2_LIB_FEATURE_RO_COMPAT_SUPP) {
                retval = EXT2_ET_RO_UNSUPP_FEATURE;
                goto cleanup;
        }

        set_field(s_rev_level, EXT2_GOOD_OLD_REV);
        if (super->s_rev_level >= EXT2_DYNAMIC_REV) {
                set_field(s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
                set_field(s_inode_size, EXT2_GOOD_OLD_INODE_SIZE);
                if (super->s_inode_size >= sizeof(struct ext2_inode_large)) {
                        int extra_isize = sizeof(struct ext2_inode_large) -
                                EXT2_GOOD_OLD_INODE_SIZE;
                        set_field(s_min_extra_isize, extra_isize);
                        set_field(s_want_extra_isize, extra_isize);
                }
        } else {
                super->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
                super->s_inode_size = EXT2_GOOD_OLD_INODE_SIZE;
        }

        set_field(s_checkinterval, 0);
        super->s_mkfs_time = super->s_lastcheck = fs->now ? fs->now : time(NULL);

        super->s_creator_os = CREATOR_OS;

        fs->fragsize = fs->blocksize = EXT2_BLOCK_SIZE(super);
        fs->cluster_ratio_bits = super->s_log_cluster_size -
                super->s_log_block_size;

        if (bigalloc_flag) {
                unsigned long long bpg;

                if (param->s_blocks_per_group &&
                    param->s_clusters_per_group &&
                    ((param->s_clusters_per_group * EXT2FS_CLUSTER_RATIO(fs)) !=
                     param->s_blocks_per_group)) {
                        retval = EXT2_ET_INVALID_ARGUMENT;
                        goto cleanup;
                }
                if (param->s_clusters_per_group)
                        assign_field(s_clusters_per_group);
                else if (param->s_blocks_per_group)
                        super->s_clusters_per_group = 
                                param->s_blocks_per_group /
                                EXT2FS_CLUSTER_RATIO(fs);
                else if (super->s_log_cluster_size + 15 < 32)
                        super->s_clusters_per_group = fs->blocksize * 8;
                else
                        super->s_clusters_per_group = (fs->blocksize - 1) * 8;
                if (super->s_clusters_per_group > EXT2_MAX_CLUSTERS_PER_GROUP(super))
                        super->s_clusters_per_group = EXT2_MAX_CLUSTERS_PER_GROUP(super);
                bpg = EXT2FS_C2B(fs,
                        (unsigned long long) super->s_clusters_per_group);
                if (bpg >= (((unsigned long long) 1) << 32)) {
                        retval = EXT2_ET_INVALID_ARGUMENT;
                        goto cleanup;
                }
                super->s_blocks_per_group = bpg;
        } else {
                set_field(s_blocks_per_group, fs->blocksize * 8);
                if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))
                        super->s_blocks_per_group = EXT2_MAX_BLOCKS_PER_GROUP(super);
                super->s_clusters_per_group = super->s_blocks_per_group;
        }

        ext2fs_blocks_count_set(super, ext2fs_blocks_count(param) &
                                ~((blk64_t) EXT2FS_CLUSTER_MASK(fs)));
        ext2fs_r_blocks_count_set(super, ext2fs_r_blocks_count(param));
        if (ext2fs_r_blocks_count(super) >= ext2fs_blocks_count(param)) {
                retval = EXT2_ET_INVALID_ARGUMENT;
                goto cleanup;
        }

        set_field(s_mmp_update_interval, 0);

        /*
         * If we're creating an external journal device, we don't need
         * to bother with the rest.
         */
        if (ext2fs_has_feature_journal_dev(super)) {
                fs->group_desc_count = 0;
                ext2fs_mark_super_dirty(fs);
                *ret_fs = fs;
                return 0;
        }

retry:
        fs->group_desc_count = (dgrp_t) ext2fs_div64_ceil(
                ext2fs_blocks_count(super) - super->s_first_data_block,
                EXT2_BLOCKS_PER_GROUP(super));
        if (fs->group_desc_count == 0) {
                retval = EXT2_ET_TOOSMALL;
                goto cleanup;
        }

        set_field(s_desc_size,
                  ext2fs_has_feature_64bit(super) ?
                  EXT2_MIN_DESC_SIZE_64BIT : 0);

        fs->desc_blocks = ext2fs_div_ceil(fs->group_desc_count,
                                          EXT2_DESC_PER_BLOCK(super));

        i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;

        if (ext2fs_has_feature_64bit(super) &&
            (ext2fs_blocks_count(super) / i) > (1ULL << 32))
                set_field(s_inodes_count, ~0U);
        else
                set_field(s_inodes_count, ext2fs_blocks_count(super) / i);

        /*
         * Make sure we have at least EXT2_FIRST_INO + 1 inodes, so
         * that we have enough inodes for the filesystem(!)
         */
        if (super->s_inodes_count < EXT2_FIRST_INODE(super)+1)
                super->s_inodes_count = EXT2_FIRST_INODE(super)+1;

        /*
         * There should be at least as many inodes as the user
         * requested.  Figure out how many inodes per group that
         * should be.  But make sure that we don't allocate more than
         * one bitmap's worth of inodes each group.
         */
        ipg = ext2fs_div_ceil(super->s_inodes_count, fs->group_desc_count);
        if (ipg > fs->blocksize * 8) {
                if (!bigalloc_flag && super->s_blocks_per_group >= 256) {
                        /* Try again with slightly different parameters */
                        super->s_blocks_per_group -= 8;
                        ext2fs_blocks_count_set(super,
                                                ext2fs_blocks_count(param));
                        super->s_clusters_per_group = super->s_blocks_per_group;
                        goto retry;
                } else {
                        retval = EXT2_ET_TOO_MANY_INODES;
                        goto cleanup;
                }
        }

        if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super))
                ipg = EXT2_MAX_INODES_PER_GROUP(super);

ipg_retry:
        super->s_inodes_per_group = ipg;

        /*
         * Make sure the number of inodes per group completely fills
         * the inode table blocks in the descriptor.  If not, add some
         * additional inodes/group.  Waste not, want not...
         */
        fs->inode_blocks_per_group = (((super->s_inodes_per_group *
                                        EXT2_INODE_SIZE(super)) +
                                       EXT2_BLOCK_SIZE(super) - 1) /
                                      EXT2_BLOCK_SIZE(super));
        super->s_inodes_per_group = ((fs->inode_blocks_per_group *
                                      EXT2_BLOCK_SIZE(super)) /
                                     EXT2_INODE_SIZE(super));
        /*
         * Finally, make sure the number of inodes per group is a
         * multiple of 8.  This is needed to simplify the bitmap
         * splicing code.
         */
        if (super->s_inodes_per_group < 8)
                super->s_inodes_per_group = 8;
        super->s_inodes_per_group &= ~7;
        fs->inode_blocks_per_group = (((super->s_inodes_per_group *
                                        EXT2_INODE_SIZE(super)) +
                                       EXT2_BLOCK_SIZE(super) - 1) /
                                      EXT2_BLOCK_SIZE(super));

        /*
         * adjust inode count to reflect the adjusted inodes_per_group
         */
        if ((__u64)super->s_inodes_per_group * fs->group_desc_count > ~0U) {
                ipg--;
                goto ipg_retry;
        }
        super->s_inodes_count = super->s_inodes_per_group *
                fs->group_desc_count;
        super->s_free_inodes_count = super->s_inodes_count;

        /*
         * check the number of reserved group descriptor table blocks
         */
        if (ext2fs_has_feature_resize_inode(super))
                rsv_gdt = calc_reserved_gdt_blocks(fs);
        else
                rsv_gdt = 0;
        set_field(s_reserved_gdt_blocks, rsv_gdt);
        if (super->s_reserved_gdt_blocks > EXT2_ADDR_PER_BLOCK(super)) {
                retval = EXT2_ET_RES_GDT_BLOCKS;
                goto cleanup;
        }

        /*
         * Calculate the maximum number of bookkeeping blocks per
         * group.  It includes the superblock, the block group
         * descriptors, the block bitmap, the inode bitmap, the inode
         * table, and the reserved gdt blocks.
         */
        overhead = (int) (3 + fs->inode_blocks_per_group +
                          super->s_reserved_gdt_blocks);

        /* Enable meta_bg if we'd lose more than 3/4 of a BG to GDT blocks. */
        if (super->s_reserved_gdt_blocks + fs->desc_blocks >
            super->s_blocks_per_group * 3 / 4)
                ext2fs_set_feature_meta_bg(fs->super);

        if (ext2fs_has_feature_meta_bg(fs->super))
                overhead++;
        else
                overhead += fs->desc_blocks;

        /* This can only happen if the user requested too many inodes */
        if (overhead > super->s_blocks_per_group) {
                retval = EXT2_ET_TOO_MANY_INODES;
                goto cleanup;
        }

        /*
         * See if the last group is big enough to support the
         * necessary data structures.  If not, we need to get rid of
         * it.  We need to recalculate the overhead for the last block
         * group, since it might or might not have a superblock
         * backup.
         */
        overhead = (int) (2 + fs->inode_blocks_per_group);
        if (ext2fs_bg_has_super(fs, fs->group_desc_count - 1))
                overhead += 1 + fs->desc_blocks + super->s_reserved_gdt_blocks;
        rem = ((ext2fs_blocks_count(super) - super->s_first_data_block) %
               super->s_blocks_per_group);
        if ((fs->group_desc_count == 1) && rem && (rem < overhead)) {
                retval = EXT2_ET_TOOSMALL;
                goto cleanup;
        }
        if (rem && (rem < overhead+50)) {
                ext2fs_blocks_count_set(super, ext2fs_blocks_count(super) -
                                        rem);
                /*
                 * If blocks count is changed, we need to recalculate
                 * reserved blocks count not to exceed 50%.
                 */
                reserved_ratio = 100.0 * ext2fs_r_blocks_count(param) /
                        ext2fs_blocks_count(param);
                ext2fs_r_blocks_count_set(super, reserved_ratio *
                        ext2fs_blocks_count(super) / 100.0);

                goto retry;
        }

        /*
         * At this point we know how big the filesystem will be.  So
         * we can do any and all allocations that depend on the block
         * count.
         */

        /* Set up the locations of the backup superblocks */
        if (ext2fs_has_feature_sparse_super2(super)) {
                if (super->s_backup_bgs[0] >= fs->group_desc_count)
                        super->s_backup_bgs[0] = fs->group_desc_count - 1;
                if (super->s_backup_bgs[1] >= fs->group_desc_count)
                        super->s_backup_bgs[1] = fs->group_desc_count - 1;
                if (super->s_backup_bgs[0] == super->s_backup_bgs[1])
                        super->s_backup_bgs[1] = 0;
                if (super->s_backup_bgs[0] > super->s_backup_bgs[1]) {
                        __u32 t = super->s_backup_bgs[0];
                        super->s_backup_bgs[0] = super->s_backup_bgs[1];
                        super->s_backup_bgs[1] = t;
                }
        }

        retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
        if (retval)
                goto cleanup;

        strcpy(buf, "block bitmap for ");
        strcat(buf, fs->device_name);
        retval = ext2fs_allocate_subcluster_bitmap(fs, buf, &fs->block_map);
        if (retval)
                goto cleanup;

        strcpy(buf, "inode bitmap for ");
        strcat(buf, fs->device_name);
        retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
        if (retval)
                goto cleanup;

        ext2fs_free_mem(&buf);

        retval = ext2fs_get_array(fs->desc_blocks, fs->blocksize,
                                &fs->group_desc);
        if (retval)
                goto cleanup;

        memset(fs->group_desc, 0, (size_t) fs->desc_blocks * fs->blocksize);

        /*
         * Reserve the superblock and group descriptors for each
         * group, and fill in the correct group statistics for group.
         * Note that although the block bitmap, inode bitmap, and
         * inode table have not been allocated (and in fact won't be
         * by this routine), they are accounted for nevertheless.
         *
         * If FLEX_BG meta-data grouping is used, only account for the
         * superblock and group descriptors (the inode tables and
         * bitmaps will be accounted for when allocated).
         */
        free_blocks = 0;
        csum_flag = ext2fs_has_group_desc_csum(fs);
        reserved_inos = super->s_first_ino;
        for (i = 0; i < fs->group_desc_count; i++) {
                /*
                 * Don't set the BLOCK_UNINIT group for the last group
                 * because the block bitmap needs to be padded.
                 */
                if (csum_flag) {
                        if (i != fs->group_desc_count - 1)
                                ext2fs_bg_flags_set(fs, i,
                                                    EXT2_BG_BLOCK_UNINIT);
                        ext2fs_bg_flags_set(fs, i, EXT2_BG_INODE_UNINIT);
                        numblocks = super->s_inodes_per_group;
                        if (reserved_inos) {
                                if (numblocks > reserved_inos) {
                                        numblocks -= reserved_inos;
                                        reserved_inos = 0;
                                } else {
                                        reserved_inos -= numblocks;
                                        numblocks = 0;
                                }
                        }
                        ext2fs_bg_itable_unused_set(fs, i, numblocks);
                }
                numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
                if (fs->super->s_log_groups_per_flex)
                        numblocks += 2 + fs->inode_blocks_per_group;

                free_blocks += numblocks;
                ext2fs_bg_free_blocks_count_set(fs, i, numblocks);
                ext2fs_bg_free_inodes_count_set(fs, i, fs->super->s_inodes_per_group);
                ext2fs_bg_used_dirs_count_set(fs, i, 0);
                ext2fs_group_desc_csum_set(fs, i);
        }
        free_blocks &= ~EXT2FS_CLUSTER_MASK(fs);
        ext2fs_free_blocks_count_set(super, free_blocks);

        c = (char) 255;
        if (((int) c) == -1) {
                super->s_flags |= EXT2_FLAGS_SIGNED_HASH;
        } else {
                super->s_flags |= EXT2_FLAGS_UNSIGNED_HASH;
        }

        ext2fs_mark_super_dirty(fs);
        ext2fs_mark_bb_dirty(fs);
        ext2fs_mark_ib_dirty(fs);

        io_channel_set_blksize(fs->io, fs->blocksize);

        *ret_fs = fs;
        return 0;
cleanup:
        free(buf);
        ext2fs_free(fs);
        return retval;
}