import ext2fs lib to prep for new e2fsprogs

git-svn-id: svn://busybox.net/trunk/busybox@10280 69ca8d6d-28ef-0310-b511-8ec308f3f277

1 files changed, 387 insertions, 0 deletions

diff --git a/e2fsprogs/ext2fs/initialize.c b/e2fsprogs/ext2fs/initialize.c
new file mode 100644
index 000000000..82cd9f1da
--- /dev/null
+++ b/e2fsprogs/ext2fs/initialize.c
@@ -0,0 +1,387 @@
+/*
+ * 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 Public
+ * License.
+ * %End-Header%
+ */
+
+#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) */
+        
+/*
+ * Note we override the kernel include file's idea of what the default
+ * check interval (never) should be.  It's a good idea to check at
+ * least *occasionally*, specially since servers will never rarely get
+ * to reboot, since Linux is so robust these days.  :-)
+ * 
+ * 180 days (six months) seems like a good value.
+ */
+#ifdef EXT2_DFL_CHECKINTERVAL
+#undef EXT2_DFL_CHECKINTERVAL
+#endif
+#define EXT2_DFL_CHECKINTERVAL (86400L * 180L)
+
+/*
+ * 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 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 = fs->blocksize / sizeof(struct ext2_group_desc);
+        unsigned long max_blocks = 0xffffffff;
+        unsigned long rsv_groups;
+        int rsv_gdb;
+
+        /* We set it at 1024x the current filesystem size, or
+         * the upper block count limit (2^32), whichever is lower.
+         */
+        if (sb->s_blocks_count < max_blocks / 1024)
+                max_blocks = sb->s_blocks_count * 1024;
+        rsv_groups = (max_blocks - sb->s_first_data_block + bpg - 1) / bpg;
+        rsv_gdb = (rsv_groups + gdpb - 1) / 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 = %lu\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;
+        int             frags_per_block;
+        unsigned int    rem;
+        unsigned int    overhead = 0;
+        blk_t           group_block;
+        unsigned int    ipg;
+        dgrp_t          i;
+        blk_t           numblocks;
+        int             rsv_gdt;
+        char            *buf;
+
+        if (!param || !param->s_blocks_count)
+                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;
+#ifdef WORDS_BIGENDIAN
+        fs->flags |= EXT2_FLAG_SWAP_BYTES;
+#endif
+        retval = manager->open(name, IO_FLAG_RW, &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))
+
+        super->s_magic = EXT2_SUPER_MAGIC;
+        super->s_state = EXT2_VALID_FS;
+
+        set_field(s_log_block_size, 0); /* default blocksize: 1024 bytes */
+        set_field(s_log_frag_size, 0); /* default fragsize: 1024 bytes */
+        set_field(s_first_data_block, super->s_log_block_size ? 0 : 1);
+        set_field(s_max_mnt_count, EXT2_DFL_MAX_MNT_COUNT);
+        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_first_meta_bg, 0);
+        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);
+        }
+
+        set_field(s_checkinterval, EXT2_DFL_CHECKINTERVAL);
+        super->s_mkfs_time = super->s_lastcheck = time(NULL);
+
+        super->s_creator_os = CREATOR_OS;
+
+        fs->blocksize = EXT2_BLOCK_SIZE(super);
+        fs->fragsize = EXT2_FRAG_SIZE(super);
+        frags_per_block = fs->blocksize / fs->fragsize;
+
+        /* default: (fs->blocksize*8) blocks/group, up to 2^16 (GDT limit) */
+        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_frags_per_group = super->s_blocks_per_group * frags_per_block;
+        
+        super->s_blocks_count = param->s_blocks_count;
+        super->s_r_blocks_count = param->s_r_blocks_count;
+        if (super->s_r_blocks_count >= param->s_blocks_count) {
+                retval = EXT2_ET_INVALID_ARGUMENT;
+                goto cleanup;
+        }
+
+        /*
+         * If we're creating an external journal device, we don't need
+         * to bother with the rest.
+         */
+        if (super->s_feature_incompat & EXT3_FEATURE_INCOMPAT_JOURNAL_DEV) {
+                fs->group_desc_count = 0;
+                ext2fs_mark_super_dirty(fs);
+                *ret_fs = fs;
+                return 0;
+        }
+
+retry:
+        fs->group_desc_count = (super->s_blocks_count -
+                                super->s_first_data_block +
+                                EXT2_BLOCKS_PER_GROUP(super) - 1)
+                / EXT2_BLOCKS_PER_GROUP(super);
+        if (fs->group_desc_count == 0) {
+                retval = EXT2_ET_TOOSMALL;
+                goto cleanup;
+        }
+        fs->desc_blocks = (fs->group_desc_count +
+                           EXT2_DESC_PER_BLOCK(super) - 1)
+                / EXT2_DESC_PER_BLOCK(super);
+
+        i = fs->blocksize >= 4096 ? 1 : 4096 / fs->blocksize;
+        set_field(s_inodes_count, super->s_blocks_count / 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 = (super->s_inodes_count + fs->group_desc_count - 1) /
+                fs->group_desc_count;
+        if (ipg > fs->blocksize * 8) {
+                if (super->s_blocks_per_group >= 256) {
+                        /* Try again with slightly different parameters */
+                        super->s_blocks_per_group -= 8;
+                        super->s_blocks_count = param->s_blocks_count;
+                        super->s_frags_per_group = super->s_blocks_per_group *
+                                frags_per_block;
+                        goto retry;
+                } else
+                        return EXT2_ET_TOO_MANY_INODES;
+        }
+
+        if (ipg > (unsigned) EXT2_MAX_INODES_PER_GROUP(super))
+                ipg = EXT2_MAX_INODES_PER_GROUP(super);
+
+        super->s_inodes_per_group = ipg;
+        if (super->s_inodes_count > ipg * fs->group_desc_count)
+                super->s_inodes_count = ipg * fs->group_desc_count;
+
+        /*
+         * 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.
+         */
+        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
+         */
+        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 (super->s_feature_compat & EXT2_FEATURE_COMPAT_RESIZE_INODE)
+                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;
+        }
+
+        /*
+         * Overhead is the number of bookkeeping blocks per group.  It
+         * includes the superblock backup, the group descriptor
+         * backups, the inode bitmap, the block bitmap, and the inode
+         * table.
+         */
+
+        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;
+
+        /* This can only happen if the user requested too many inodes */
+        if (overhead > super->s_blocks_per_group)
+                return EXT2_ET_TOO_MANY_INODES;
+
+        /*
+         * See if the last group is big enough to support the
+         * necessary data structures.  If not, we need to get rid of
+         * it.
+         */
+        rem = ((super->s_blocks_count - super->s_first_data_block) %
+               super->s_blocks_per_group);
+        if ((fs->group_desc_count == 1) && rem && (rem < overhead))
+                return EXT2_ET_TOOSMALL;
+        if (rem && (rem < overhead+50)) {
+                super->s_blocks_count -= rem;
+                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.
+         */
+
+        retval = ext2fs_get_mem(strlen(fs->device_name) + 80, &buf);
+        if (retval)
+                goto cleanup;
+        
+        sprintf(buf, "block bitmap for %s", fs->device_name);
+        retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
+        if (retval)
+                goto cleanup;
+        
+        sprintf(buf, "inode bitmap for %s", fs->device_name);
+        retval = ext2fs_allocate_inode_bitmap(fs, buf, &fs->inode_map);
+        if (retval)
+                goto cleanup;
+
+        ext2fs_free_mem(&buf);
+
+        retval = ext2fs_get_mem((size_t) 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.
+         */
+        group_block = super->s_first_data_block;
+        super->s_free_blocks_count = 0;
+        for (i = 0; i < fs->group_desc_count; i++) {
+                numblocks = ext2fs_reserve_super_and_bgd(fs, i, fs->block_map);
+
+                super->s_free_blocks_count += numblocks;
+                fs->group_desc[i].bg_free_blocks_count = numblocks;
+                fs->group_desc[i].bg_free_inodes_count =
+                        fs->super->s_inodes_per_group;
+                fs->group_desc[i].bg_used_dirs_count = 0;
+                
+                group_block += super->s_blocks_per_group;
+        }
+        
+        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:
+        ext2fs_free(fs);
+        return retval;
+}