mkfs_ext2: make it able to create images larger than 4G

function old new delta mkfs_ext2_main 1904 2145 +241 has_super 29 23 -6 PUT 52 40 -12 packed_usage 26807 26792 -15 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 1/3 up/down: 241/-33) Total: 208 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
author: Denys Vlasenko <vda.linux@googlemail.com> 2009-10-18 16:29:30 +0200
committer: Denys Vlasenko <vda.linux@googlemail.com> 2009-10-18 16:29:30 +0200
commit: 77da1cae94acbeef90da66bf6530556fe191a6e2 (patch)
tree: 712db9a18d648b14cc6c7e587e8c4edbe11fd079 /util-linux/mkfs_ext2.c
parent: f37eb3999bce2ea46fef0214e33279b81609e596 (diff)
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1 files changed, 95 insertions, 55 deletions
diff --git a/util-linux/mkfs_ext2.c b/util-linux/mkfs_ext2.c
index 8df9f1a66..a990668df 100644
--- a/util-linux/mkfs_ext2.c
+++ b/util-linux/mkfs_ext2.c
@@ -77,33 +77,18 @@ static void allocate(uint8_t *bitmap, uint32_t blocksize, uint32_t start, uint32
 {
        uint32_t i;
        memset(bitmap, 0, blocksize);
-        i = start/8;
+        i = start / 8;
        memset(bitmap, 0xFF, i);
        bitmap[i] = 0xFF >> (8-(start&7));
 //bb_info_msg("ALLOC: [%u][%u][%u]: [%u]:=[%x]", blocksize, start, end, blocksize - end/8 - 1, (uint8_t)(0xFF << (8-(end&7))));
-        i = end/8;
+        i = end / 8;
-        bitmap[blocksize - i - 1] = 0xFF << (8-(end&7));
+        bitmap[blocksize - i - 1] = 0xFF << (8 - (end & 7));
        memset(bitmap + blocksize - i, 0xFF, i); // N.B. no overflow here!
 }
-#if 0
-// TODO: get rid of FPU
-static bool is_power_of(uint32_t x, uint16_t n)
-{
-//      return (!(x % n) && is_power_of(x / n, n));
-        double z = logf(x)/logf(n);
-        return (z == (int)z);
-}
-static uint32_t has_super(uint32_t x)
-{
-        return (0 == x || 1 == x || is_power_of(x, 3) || is_power_of(x, 5) || is_power_of(x, 7));
-}
-#else
 static uint32_t has_super(uint32_t x)
 {
+        // 0, 1 and powers of 3, 5, 7 up to 2^32 limit
        static const uint32_t supers[] = {
                0, 1, 3, 5, 7, 9, 25, 27, 49, 81, 125, 243, 343, 625, 729,
                2187, 2401, 3125, 6561, 15625, 16807, 19683, 59049, 78125,
@@ -112,16 +97,15 @@ static uint32_t has_super(uint32_t x)
                48828125, 129140163, 244140625, 282475249, 387420489,
                1162261467, 1220703125, 1977326743, 3486784401/* >2^31 */,
        };
-        const uint32_t *sp = supers + ARRAY_SIZE(supers)-1;
+        const uint32_t *sp = supers + ARRAY_SIZE(supers);
        while (1) {
+                sp--;
                if (x == *sp)
                        return 1;
-                if (0 == *sp)
+                if (x > *sp)
                        return 0;
-                sp--;
        }
 }
-#endif
 /* Standard mke2fs 1.41.9:
 * Usage: mke2fs [-c|-l filename] [-b block-size] [-f fragment-size]
@@ -154,7 +138,7 @@ enum {
        OPT_T = 1 << 17,
        OPT_U = 1 << 18,
        OPT_j = 1 << 19,
-        OPT_n = 1 << 20,
+        OPT_n = 1 << 20,        // dry run: do not write anything
        OPT_q = 1 << 21,
        OPT_v = 1 << 22,
        OPT_F = 1 << 23,
@@ -166,17 +150,16 @@ enum {
 static void PUT(uint64_t off, void *buf, uint32_t size)
 {
-        if (!(option_mask32 & OPT_n)) {
+//      bb_info_msg("PUT[%llu]:[%u]", off, size);
-                xlseek(fd, off, SEEK_SET);
+        xlseek(fd, off, SEEK_SET);
-                xwrite(fd, buf, size);
+        xwrite(fd, buf, size);
-        }
 }
 int mkfs_ext2_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
 {
        unsigned i, pos, n;
-        unsigned bs, blocksize;
+        unsigned bs, blocksize, blocksize_log2;
        unsigned nreserved = 5;
        uint32_t nblocks;
        uint32_t ngroups;
@@ -235,7 +218,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
        // TODO: 0/5 info printing
        // TODO: 2/5 bigendianness! Spot where it comes to play! sb->, gd->
        // TODO: 2/5 reserved GDT: how to mark but not allocate?
-        // TODO: 0/5 dir_index?
+        // TODO: 3/5 dir_index?
        // fill the superblock
        sb = xzalloc(blocksize);
@@ -243,13 +226,14 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
        sb->s_magic = EXT2_SUPER_MAGIC;
        sb->s_inode_size = sizeof(*inode);
        sb->s_first_ino = EXT2_GOOD_OLD_FIRST_INO;
-        sb->s_log_block_size = sb->s_log_frag_size = int_log2(blocksize >> EXT2_MIN_BLOCK_LOG_SIZE);
+        blocksize_log2 = int_log2(blocksize);
+        sb->s_log_block_size = sb->s_log_frag_size = blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE;
        // first 1024 bytes of the device are for boot record. If block size is 1024 bytes, then
        // the first block available for data is 1, otherwise 0
        first_data_block = sb->s_first_data_block = (EXT2_MIN_BLOCK_SIZE == blocksize);
        // block and inode bitmaps occupy no more than one block, so maximum number of blocks is
        // number of bits in one block, i.e. 8*blocksize
-        nblocks_per_group = sb->s_blocks_per_group = sb->s_frags_per_group = sb->s_inodes_per_group = 8*blocksize;
+        nblocks_per_group = sb->s_blocks_per_group = sb->s_frags_per_group = sb->s_inodes_per_group = 8 * blocksize;
        timestamp = time(NULL);
        sb->s_mkfs_time = sb->s_wtime = sb->s_lastcheck = timestamp;
        sb->s_state = 1;
@@ -266,10 +250,10 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
        sb->s_feature_ro_compat = EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER;
        sb->s_flags = EXT2_FLAGS_SIGNED_HASH * ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX;
        generate_uuid(sb->s_uuid);
-#if ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX
+        if (ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX) {
-        sb->s_def_hash_version = EXT2_HASH_HALF_MD4;
+                sb->s_def_hash_version = EXT2_HASH_HALF_MD4;
-        generate_uuid((uint8_t *)sb->s_hash_seed);
+                generate_uuid((uint8_t *)sb->s_hash_seed);
-#endif
+        }
        /*
         * From e2fsprogs: add "jitter" to the superblock's check interval so that we
         * don't check all the filesystems at the same time.  We use a
@@ -282,7 +266,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
        if (argv[1]) {
                nblocks = xatou(argv[1]);
        } else {
-                nblocks = ((uoff_t)xlseek(fd, 0, SEEK_END)) / blocksize;
+                nblocks = (uoff_t)xlseek(fd, 0, SEEK_END) >> blocksize_log2;
        }
        sb->s_blocks_count = nblocks;
@@ -328,17 +312,17 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
                if (nblocks < 3*1024)
                        bytes_per_inode = 8192;
        }
-        ninodes = nblocks / (bytes_per_inode / blocksize);
+        ninodes = nblocks / (bytes_per_inode >> blocksize_log2);
        if (ninodes < EXT2_GOOD_OLD_FIRST_INO+1)
                ninodes = EXT2_GOOD_OLD_FIRST_INO+1;
        ninodes_per_group = div_roundup(ninodes, ngroups);
        if (ninodes_per_group < 16)
-                ninodes_per_group = 16; // minimum number because the first 10 are reserved
+                ninodes_per_group = 16; // minimum number because the first EXT2_GOOD_OLD_FIRST_INO-1 are reserved
        // N.B. a block group can have no more than 8*blocksize = sb->s_inodes_per_group inodes
        if (ninodes_per_group > sb->s_inodes_per_group)
                ninodes_per_group = sb->s_inodes_per_group;
        // adjust inodes per group so they completely fill the inode table blocks in the descriptor
-        ninodes_per_group = ((div_roundup(ninodes_per_group * EXT2_INODE_SIZE(sb), blocksize) * blocksize) / EXT2_INODE_SIZE(sb));
+        ninodes_per_group = (div_roundup(ninodes_per_group * EXT2_INODE_SIZE(sb), blocksize) << blocksize_log2) / EXT2_INODE_SIZE(sb);
        // make sure the number of inodes per group is a multiple of 8
        ninodes_per_group &= ~7;
        sb->s_inodes_per_group = ninodes_per_group;// = div_roundup(ninodes_per_group * sb->s_inode_size, blocksize);
@@ -352,6 +336,52 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
        if (opts & OPT_L)
                safe_strncpy((char *)sb->s_volume_name, label, sizeof(sb->s_volume_name));
+#if 1
+/*      if (fs_param.s_blocks_count != s->s_blocks_count)
+                fprintf(stderr, _("warning: %u blocks unused.\n\n"),
+                       fs_param.s_blocks_count - s->s_blocks_count);
+*/
+        printf(
+                "Filesystem label=%s\n"
+                "OS type: Linux\n"
+                "Block size=%u (log=%u)\n"
+                "Fragment size=%u (log=%u)\n"
+                "%u inodes, %u blocks\n"
+                "%u blocks (%u%%) reserved for the super user\n"
+                "First data block=%u\n"
+//              "Maximum filesystem blocks=%lu\n"
+                "%u block groups\n"
+                "%u blocks per group, %u fragments per group\n"
+                "%u inodes per group"
+                , (char *)sb->s_volume_name
+                , blocksize, sb->s_log_block_size
+                , blocksize, sb->s_log_block_size
+                , sb->s_inodes_count, sb->s_blocks_count
+                , sb->s_r_blocks_count, nreserved
+                , first_data_block
+//              , (rgdtsz + gdtsz) * EXT2_DESC_PER_BLOCK(sb) * nblocks_per_group
+                , ngroups
+                , nblocks_per_group, nblocks_per_group
+                , ninodes_per_group
+        );
+        {
+                const char *fmt = "\nSuperblock backups stored on blocks: %u";
+                pos = first_data_block;
+                for (i = 1; i < ngroups; i++) {
+                        pos += nblocks_per_group;
+                        if (has_super(i)) {
+                                printf(fmt, (unsigned)pos);
+                                fmt = ", %u";
+                        }
+                }
+        }
+        bb_putchar('\n');
+#endif
+        if (opts & OPT_n)
+                return EXIT_SUCCESS;
        // fill group descriptors
        gd = xzalloc((gdtsz + rgdtsz) * blocksize);
        sb->s_free_blocks_count = 0;
@@ -365,8 +395,8 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
                gd[i].bg_inode_table  = overhead + 2;
                overhead = overhead - pos + 1/*bbmp*/ + 1/*ibmp*/ + itsz;
                gd[i].bg_free_inodes_count = ninodes_per_group;
-                // N.B. both root and lost+found dirs are within the first block group, thus +2
                //gd[i].bg_used_dirs_count = 0;
+                // N.B. both root and lost+found dirs are within the first block group, thus +2
                if (0 == i) {
                        overhead += 2;
                        gd[i].bg_used_dirs_count = 2;
@@ -383,6 +413,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
        STORE_LE(sb->s_free_blocks_count, sb->s_free_blocks_count);
        // dump filesystem skeleton structures
+//      printf("Writing superblocks and filesystem accounting information: ");
        buf = xmalloc(blocksize);
        for (i = 0, pos = first_data_block; i < ngroups; i++, pos += nblocks_per_group) {
                uint32_t overhead = has_super(i) ? (1/*sb*/ + gdtsz + rgdtsz) : 0;
@@ -391,28 +422,30 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
                // dump superblock and group descriptors and their backups
                if (overhead) { // N.B. in fact, we want (has_super(i)) condition, but it is equal to (overhead != 0) and is cheaper
-//bb_info_msg("SUPER@[%d]", pos);
                        // N.B. 1024 byte blocks are special
-                        PUT(blocksize * pos + ((0 == i && 0 == first_data_block) ? 1024 : 0), sb, blocksize);
+                        PUT(((uint64_t)pos << blocksize_log2) + ((0 == i && 0 == first_data_block) ? 1024 : 0), sb, 1024);//blocksize);
-                        PUT(blocksize * pos + blocksize, gd, (gdtsz + rgdtsz) * blocksize);
+                        PUT(((uint64_t)pos << blocksize_log2) + blocksize, gd, (gdtsz + rgdtsz) * blocksize);
                }
                start = overhead + 1/*bbmp*/ + 1/*ibmp*/ + itsz;
                if (i == 0)
-                        start += 2; // for / and /lost+found
+                        start += 2; // for "/" and "/lost+found"
                end = nblocks_per_group - (start + gd[i].bg_free_blocks_count);
                // mark preallocated blocks as allocated
                allocate(buf, blocksize, start, end);
                // dump block bitmap
-                PUT((pos + overhead) * blocksize, buf, blocksize);
+                PUT((uint64_t)(pos + overhead) * blocksize, buf, blocksize);
                // mark preallocated inodes as allocated
                allocate(buf, blocksize,
                        ninodes_per_group - gd[i].bg_free_inodes_count,
-                        8*blocksize - ninodes_per_group
+                        8 * blocksize - ninodes_per_group
                );
                // dump inode bitmap
-                PUT((pos + overhead + 1) * blocksize, buf, blocksize);
+                //PUT((uint64_t)(pos + overhead + 1) * blocksize, buf, blocksize);
+                //but it's right after block bitmap, so we can just:
+                xwrite(fd, buf, blocksize);
        }
        // zero boot sectors
@@ -421,12 +454,13 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
        // zero inode tables
        for (i = 0; i < ngroups; ++i)
                for (n = 0; n < itsz; ++n)
-                        PUT((gd[i].bg_inode_table + n) * blocksize, buf, blocksize);
+                        PUT((uint64_t)(gd[i].bg_inode_table + n) * blocksize, buf, blocksize);
        // prepare directory inode
        inode = (struct ext2_inode *)buf;
        STORE_LE(inode->i_mode, S_IFDIR | S_IRWXU | S_IRGRP | S_IROTH | S_IXGRP | S_IXOTH);
-        inode->i_mtime = inode->i_atime = timestamp;
+        STORE_LE(inode->i_mtime, timestamp);
+        STORE_LE(inode->i_atime, timestamp);
        STORE_LE(inode->i_ctime, timestamp);
        STORE_LE(inode->i_size, blocksize);
        // N.B. inode->i_blocks stores the number of 512 byte data blocks. Why on Earth?!
@@ -435,12 +469,12 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
        // dump root dir inode
        STORE_LE(inode->i_links_count, 3); // "/.", "/..", "/lost+found/.." point to this inode
        STORE_LE(inode->i_block[0], gd[0].bg_inode_table + itsz);
-        PUT(gd[0].bg_inode_table * blocksize + (EXT2_ROOT_INO-1) * sizeof(*inode), buf, sizeof(*inode));
+        PUT(((uint64_t)gd[0].bg_inode_table << blocksize_log2) + (EXT2_ROOT_INO-1) * sizeof(*inode), buf, sizeof(*inode));
        // dump lost+found dir inode
        STORE_LE(inode->i_links_count, 2); // both "/lost+found" and "/lost+found/." point to this inode
        STORE_LE(inode->i_block[0], inode->i_block[0]+1); // use next block //= gd[0].bg_inode_table + itsz + 1;
-        PUT(gd[0].bg_inode_table * blocksize + (EXT2_GOOD_OLD_FIRST_INO-1) * sizeof(*inode), buf, sizeof(*inode));
+        PUT(((uint64_t)gd[0].bg_inode_table << blocksize_log2) + (EXT2_GOOD_OLD_FIRST_INO-1) * sizeof(*inode), buf, sizeof(*inode));
        // dump directories
        memset(buf, 0, blocksize);
@@ -457,7 +491,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
        STORE_LE(dir->name_len2, 2);
        STORE_LE(dir->file_type2, EXT2_FT_DIR);
        dir->name2[0] = '.'; dir->name2[1] = '.';
-        PUT((gd[0].bg_inode_table + itsz + 1) * blocksize, buf, blocksize);
+        PUT((uint64_t)(gd[0].bg_inode_table + itsz + 1) * blocksize, buf, blocksize);
        // dump root dir block
        STORE_LE(dir->inode1, EXT2_ROOT_INO);
@@ -467,15 +501,21 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
        STORE_LE(dir->name_len3, 10);
        STORE_LE(dir->file_type3, EXT2_FT_DIR);
        strcpy(dir->name3, "lost+found");
-        PUT((gd[0].bg_inode_table + itsz + 0) * blocksize, buf, blocksize);
+        PUT((uint64_t)(gd[0].bg_inode_table + itsz + 0) * blocksize, buf, blocksize);
+//      bb_info_msg("done\n"
+//              "This filesystem will be automatically checked every %u mounts or\n"
+//              "%u days, whichever comes first. Use tune2fs -c or -i to override.",
+//              sb->s_max_mnt_count, sb->s_checkinterval / (3600 * 24)
+//      );
        // cleanup
        if (ENABLE_FEATURE_CLEAN_UP) {
                free(buf);
                free(gd);
                free(sb);
-                close(fd);
        }
+        xclose(fd);
        return EXIT_SUCCESS;
 }
author	Denys Vlasenko <vda.linux@googlemail.com>	2009-10-18 16:29:30 +0200
committer	Denys Vlasenko <vda.linux@googlemail.com>	2009-10-18 16:29:30 +0200
commit	77da1cae94acbeef90da66bf6530556fe191a6e2 (patch)
tree	712db9a18d648b14cc6c7e587e8c4edbe11fd079 /util-linux/mkfs_ext2.c
parent	f37eb3999bce2ea46fef0214e33279b81609e596 (diff)
download	busybox-w32-77da1cae94acbeef90da66bf6530556fe191a6e2.tar.gz busybox-w32-77da1cae94acbeef90da66bf6530556fe191a6e2.tar.bz2 busybox-w32-77da1cae94acbeef90da66bf6530556fe191a6e2.zip