busybox/util-linux/mkfs_ext2.c

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/* vi: set sw=4 ts=4: */
/*
* mkfs_ext2: utility to create EXT2 filesystem
* inspired by genext2fs
*
* Busybox'ed (2009) by Vladimir Dronnikov <dronnikov@gmail.com>
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
//config:config MKE2FS
//config: bool "mke2fs (10 kb)"
//config: default y
//config: select PLATFORM_LINUX
//config: help
//config: Utility to create EXT2 filesystems.
//config:
//config:config MKFS_EXT2
//config: bool "mkfs.ext2 (10 kb)"
//config: default y
//config: select PLATFORM_LINUX
//config: help
//config: Alias to "mke2fs".
// APPLET_ODDNAME:name main location suid_type help
//applet:IF_MKE2FS( APPLET_ODDNAME(mke2fs, mkfs_ext2, BB_DIR_SBIN, BB_SUID_DROP, mkfs_ext2))
//applet:IF_MKFS_EXT2(APPLET_ODDNAME(mkfs.ext2, mkfs_ext2, BB_DIR_SBIN, BB_SUID_DROP, mkfs_ext2))
////////:IF_MKFS_EXT3(APPLET_ODDNAME(mkfs.ext3, mkfs_ext2, BB_DIR_SBIN, BB_SUID_DROP, mkfs_ext2))
//kbuild:lib-$(CONFIG_MKE2FS) += mkfs_ext2.o
//kbuild:lib-$(CONFIG_MKFS_EXT2) += mkfs_ext2.o
//usage:#define mkfs_ext2_trivial_usage
//usage: "[-Fn] "
/* //usage: "[-c|-l filename] " */
//usage: "[-b BLK_SIZE] "
/* //usage: "[-f fragment-size] [-g blocks-per-group] " */
//usage: "[-i INODE_RATIO] [-I INODE_SIZE] "
/* //usage: "[-j] [-J journal-options] [-N number-of-inodes] " */
//usage: "[-m RESERVED_PERCENT] "
/* //usage: "[-o creator-os] [-O feature[,...]] [-q] " */
/* //usage: "[r fs-revision-level] [-E extended-options] [-v] [-F] " */
//usage: "[-L LABEL] "
/* //usage: "[-M last-mounted-directory] [-S] [-T filesystem-type] " */
//usage: "BLOCKDEV [KBYTES]"
//usage:#define mkfs_ext2_full_usage "\n\n"
//usage: " -b BLK_SIZE Block size, bytes"
/* //usage: "\n -c Check device for bad blocks" */
/* //usage: "\n -E opts Set extended options" */
/* //usage: "\n -f size Fragment size in bytes" */
//usage: "\n -F Force"
/* //usage: "\n -g N Number of blocks in a block group" */
//usage: "\n -i RATIO Max number of files is filesystem_size / RATIO"
//usage: "\n -I BYTES Inode size (min 128)"
/* //usage: "\n -j Create a journal (ext3)" */
/* //usage: "\n -J opts Set journal options (size/device)" */
/* //usage: "\n -l file Read bad blocks list from file" */
//usage: "\n -L LBL Volume label"
//usage: "\n -m PERCENT Percent of blocks to reserve for admin"
/* //usage: "\n -M dir Set last mounted directory" */
//usage: "\n -n Dry run"
/* //usage: "\n -N N Number of inodes to create" */
/* //usage: "\n -o os Set the 'creator os' field" */
/* //usage: "\n -O features Dir_index/filetype/has_journal/journal_dev/sparse_super" */
/* //usage: "\n -q Quiet" */
/* //usage: "\n -r rev Set filesystem revision" */
/* //usage: "\n -S Write superblock and group descriptors only" */
/* //usage: "\n -T fs-type Set usage type (news/largefile/largefile4)" */
/* //usage: "\n -v Verbose" */
#include "libbb.h"
#include <linux/fs.h>
#include "bb_e2fs_defs.h"
#define ENABLE_FEATURE_MKFS_EXT2_RESERVED_GDT 0
#define ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX 1
#define EXT2_HASH_HALF_MD4 1
#define EXT2_FLAGS_SIGNED_HASH 0x0001
#define EXT2_FLAGS_UNSIGNED_HASH 0x0002
// All fields are little-endian
struct ext2_dir {
uint32_t inode1;
uint16_t rec_len1;
uint8_t name_len1;
uint8_t file_type1;
char name1[4];
uint32_t inode2;
uint16_t rec_len2;
uint8_t name_len2;
uint8_t file_type2;
char name2[4];
uint32_t inode3;
uint16_t rec_len3;
uint8_t name_len3;
uint8_t file_type3;
char name3[12];
};
static unsigned int_log2(unsigned arg)
{
unsigned r = 0;
while ((arg >>= 1) != 0)
r++;
return r;
}
// taken from mkfs_minix.c. libbb candidate?
// "uint32_t size", since we never use it for anything >32 bits
static uint32_t div_roundup(uint32_t size, uint32_t n)
{
// Overflow-resistant
uint32_t res = size / n;
if (res * n != size)
res++;
return res;
}
static void allocate(uint8_t *bitmap, uint32_t blocksize, uint32_t start, uint32_t end)
{
uint32_t i;
//bb_error_msg("ALLOC: [%u][%u][%u]: [%u-%u]:=[%x],[%x]", blocksize, start, end, start/8, blocksize - end/8 - 1, (1 << (start & 7)) - 1, (uint8_t)(0xFF00 >> (end & 7)));
memset(bitmap, 0, blocksize);
i = start / 8;
memset(bitmap, 0xFF, i);
bitmap[i] = (1 << (start & 7)) - 1; //0..7 => 00000000..01111111
i = end / 8;
bitmap[blocksize - i - 1] |= 0x7F00 >> (end & 7); //0..7 => 00000000..11111110
memset(bitmap + blocksize - i, 0xFF, i); // N.B. no overflow here!
}
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,
117649, 177147, 390625, 531441, 823543, 1594323, 1953125,
4782969, 5764801, 9765625, 14348907, 40353607, 43046721,
48828125, 129140163, 244140625, 282475249, 387420489,
1162261467, 1220703125, 1977326743, 3486784401/* >2^31 */,
};
const uint32_t *sp = supers + ARRAY_SIZE(supers);
while (1) {
sp--;
if (x == *sp)
return 1;
if (x > *sp)
return 0;
}
}
#define fd 3 /* predefined output descriptor */
static void PUT(uint64_t off, void *buf, uint32_t size)
{
//bb_error_msg("PUT[%llu]:[%u]", off, size);
xlseek(fd, off, SEEK_SET);
xwrite(fd, buf, size);
}
// 128 and 256-byte inodes:
// 128-byte inode is described by struct ext2_inode.
// 256-byte one just has these fields appended:
// __u16 i_extra_isize;
// __u16 i_pad1;
// __u32 i_ctime_extra; /* extra Change time (nsec << 2 | epoch) */
// __u32 i_mtime_extra; /* extra Modification time (nsec << 2 | epoch) */
// __u32 i_atime_extra; /* extra Access time (nsec << 2 | epoch) */
// __u32 i_crtime; /* File creation time */
// __u32 i_crtime_extra; /* extra File creation time (nsec << 2 | epoch)*/
// __u32 i_version_hi; /* high 32 bits for 64-bit version */
// the rest is padding.
//
// linux/ext2_fs.h has "#define i_size_high i_dir_acl" which suggests that even
// 128-byte inode is capable of describing large files (i_dir_acl is meaningful
// only for directories, which never need i_size_high).
//
// Standard mke2fs creates a filesystem with 256-byte inodes if it is
// bigger than 0.5GB.
// Standard mke2fs 1.41.9:
// Usage: mke2fs [-c|-l filename] [-b block-size] [-f fragment-size]
// [-i bytes-per-inode] [-I inode-size] [-J journal-options]
// [-G meta group size] [-N number-of-inodes]
// [-m reserved-blocks-percentage] [-o creator-os]
// [-g blocks-per-group] [-L volume-label] [-M last-mounted-directory]
// [-O feature[,...]] [-r fs-revision] [-E extended-option[,...]]
// [-T fs-type] [-U UUID] [-jnqvFSV] device [blocks-count]
//
// Options not commented below are taken but silently ignored:
enum {
OPT_c = 1 << 0,
OPT_l = 1 << 1,
OPT_b = 1 << 2, // block size, in bytes
OPT_f = 1 << 3,
OPT_i = 1 << 4, // bytes per inode
OPT_I = 1 << 5, // custom inode size, in bytes
OPT_J = 1 << 6,
OPT_G = 1 << 7,
OPT_N = 1 << 8,
OPT_m = 1 << 9, // percentage of blocks reserved for superuser
OPT_o = 1 << 10,
OPT_g = 1 << 11,
OPT_L = 1 << 12, // label
OPT_M = 1 << 13,
OPT_O = 1 << 14,
OPT_r = 1 << 15,
OPT_E = 1 << 16,
OPT_T = 1 << 17,
OPT_U = 1 << 18,
OPT_j = 1 << 19,
OPT_n = 1 << 20, // dry run: do not write anything
OPT_q = 1 << 21,
OPT_v = 1 << 22,
OPT_F = 1 << 23,
OPT_S = 1 << 24,
//OPT_V = 1 << 25, // -V version. bbox applets don't support that
};
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, bpi;
unsigned blocksize, blocksize_log2;
unsigned inodesize, user_inodesize;
unsigned reserved_percent = 5;
unsigned long long kilobytes;
uint32_t nblocks, nblocks_full;
uint32_t nreserved;
uint32_t ngroups;
uint32_t bytes_per_inode;
uint32_t first_block;
uint32_t inodes_per_group;
uint32_t group_desc_blocks;
uint32_t inode_table_blocks;
uint32_t lost_and_found_blocks;
time_t timestamp;
const char *label = "";
struct stat st;
struct ext2_super_block *sb; // superblock
struct ext2_group_desc *gd; // group descriptors
struct ext2_inode *inode;
struct ext2_dir *dir;
uint8_t *buf;
// using global "option_mask32" instead of local "opts":
// we are register starved here
/*opts =*/ getopt32(argv, "cl:b:+f:i:+I:+J:G:N:m:+o:g:L:M:O:r:E:T:U:jnqvFS",
/*lbfi:*/ NULL, &bs, NULL, &bpi,
/*IJGN:*/ &user_inodesize, NULL, NULL, NULL,
/*mogL:*/ &reserved_percent, NULL, NULL, &label,
/*MOrE:*/ NULL, NULL, NULL, NULL,
/*TU:*/ NULL, NULL);
argv += optind; // argv[0] -- device
// open the device, check the device is a block device
xmove_fd(xopen(argv[0], O_WRONLY), fd);
xfstat(fd, &st, argv[0]);
if (!S_ISBLK(st.st_mode) && !(option_mask32 & OPT_F))
bb_error_msg_and_die("%s: not a block device", argv[0]);
// check if it is mounted
// N.B. what if we format a file? find_mount_point will return false negative since
// it is loop block device which is mounted!
if (find_mount_point(argv[0], 0))
libbb: reduce the overhead of single parameter bb_error_msg() calls Back in 2007, commit 0c97c9d43707 ("'simple' error message functions by Loic Grenie") introduced bb_simple_perror_msg() to allow for a lower overhead call to bb_perror_msg() when only a string was being printed with no parameters. This saves space for some CPU architectures because it avoids the overhead of a call to a variadic function. However there has never been a simple version of bb_error_msg(), and since 2007 many new calls to bb_perror_msg() have been added that only take a single parameter and so could have been using bb_simple_perror_message(). This changeset introduces 'simple' versions of bb_info_msg(), bb_error_msg(), bb_error_msg_and_die(), bb_herror_msg() and bb_herror_msg_and_die(), and replaces all calls that only take a single parameter, or use something like ("%s", arg), with calls to the corresponding 'simple' version. Since it is likely that single parameter calls to the variadic functions may be accidentally reintroduced in the future a new debugging config option WARN_SIMPLE_MSG has been introduced. This uses some macro magic which will cause any such calls to generate a warning, but this is turned off by default to avoid use of the unpleasant macros in normal circumstances. This is a large changeset due to the number of calls that have been replaced. The only files that contain changes other than simple substitution of function calls are libbb.h, libbb/herror_msg.c, libbb/verror_msg.c and libbb/xfuncs_printf.c. In miscutils/devfsd.c, networking/udhcp/common.h and util-linux/mdev.c additonal macros have been added for logging so that single parameter and multiple parameter logging variants exist. The amount of space saved varies considerably by architecture, and was found to be as follows (for 'defconfig' using GCC 7.4): Arm: -92 bytes MIPS: -52 bytes PPC: -1836 bytes x86_64: -938 bytes Note that for the MIPS architecture only an exception had to be made disabling the 'simple' calls for 'udhcp' (in networking/udhcp/common.h) because it made these files larger on MIPS. Signed-off-by: James Byrne <james.byrne@origamienergy.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2019-07-02 15:05:03 +05:30
bb_simple_error_msg_and_die("can't format mounted filesystem");
// get size in kbytes
kilobytes = get_volume_size_in_bytes(fd, argv[1], 1024, /*extend:*/ !(option_mask32 & OPT_n)) / 1024;
bytes_per_inode = 16384;
if (kilobytes < 512*1024)
bytes_per_inode = 4096;
if (kilobytes < 3*1024)
bytes_per_inode = 8192;
if (option_mask32 & OPT_i)
bytes_per_inode = bpi;
// Determine block size and inode size
// block size is a multiple of 1024
// inode size is a multiple of 128
blocksize = 1024;
inodesize = sizeof(struct ext2_inode); // 128
if (kilobytes >= 512*1024) { // mke2fs 1.41.9 compat
blocksize = 4096;
inodesize = 256;
}
if (EXT2_MAX_BLOCK_SIZE > 4096) {
// kilobytes >> 22 == size in 4gigabyte chunks.
// if size >= 16k gigs, blocksize must be increased.
// Try "mke2fs -F image $((16 * 1024*1024*1024))"
while ((kilobytes >> 22) >= blocksize)
blocksize *= 2;
}
if (option_mask32 & OPT_b)
blocksize = bs;
if (blocksize < EXT2_MIN_BLOCK_SIZE
|| blocksize > EXT2_MAX_BLOCK_SIZE
|| (blocksize & (blocksize - 1)) // not power of 2
) {
bb_error_msg_and_die("blocksize %u is bad", blocksize);
}
// Do we have custom inode size?
if (option_mask32 & OPT_I) {
if (user_inodesize < sizeof(*inode)
|| user_inodesize > blocksize
|| (user_inodesize & (user_inodesize - 1)) // not power of 2
) {
bb_error_msg("-%c is bad", 'I');
} else {
inodesize = user_inodesize;
}
}
if ((int32_t)bytes_per_inode < blocksize)
bb_error_msg_and_die("-%c is bad", 'i');
// number of bits in one block, i.e. 8*blocksize
#define blocks_per_group (8 * blocksize)
first_block = (EXT2_MIN_BLOCK_SIZE == blocksize);
blocksize_log2 = int_log2(blocksize);
// Determine number of blocks
kilobytes >>= (blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE);
nblocks = kilobytes;
if (nblocks != kilobytes)
libbb: reduce the overhead of single parameter bb_error_msg() calls Back in 2007, commit 0c97c9d43707 ("'simple' error message functions by Loic Grenie") introduced bb_simple_perror_msg() to allow for a lower overhead call to bb_perror_msg() when only a string was being printed with no parameters. This saves space for some CPU architectures because it avoids the overhead of a call to a variadic function. However there has never been a simple version of bb_error_msg(), and since 2007 many new calls to bb_perror_msg() have been added that only take a single parameter and so could have been using bb_simple_perror_message(). This changeset introduces 'simple' versions of bb_info_msg(), bb_error_msg(), bb_error_msg_and_die(), bb_herror_msg() and bb_herror_msg_and_die(), and replaces all calls that only take a single parameter, or use something like ("%s", arg), with calls to the corresponding 'simple' version. Since it is likely that single parameter calls to the variadic functions may be accidentally reintroduced in the future a new debugging config option WARN_SIMPLE_MSG has been introduced. This uses some macro magic which will cause any such calls to generate a warning, but this is turned off by default to avoid use of the unpleasant macros in normal circumstances. This is a large changeset due to the number of calls that have been replaced. The only files that contain changes other than simple substitution of function calls are libbb.h, libbb/herror_msg.c, libbb/verror_msg.c and libbb/xfuncs_printf.c. In miscutils/devfsd.c, networking/udhcp/common.h and util-linux/mdev.c additonal macros have been added for logging so that single parameter and multiple parameter logging variants exist. The amount of space saved varies considerably by architecture, and was found to be as follows (for 'defconfig' using GCC 7.4): Arm: -92 bytes MIPS: -52 bytes PPC: -1836 bytes x86_64: -938 bytes Note that for the MIPS architecture only an exception had to be made disabling the 'simple' calls for 'udhcp' (in networking/udhcp/common.h) because it made these files larger on MIPS. Signed-off-by: James Byrne <james.byrne@origamienergy.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2019-07-02 15:05:03 +05:30
bb_simple_error_msg_and_die("block count doesn't fit in 32 bits");
#define kilobytes kilobytes_unused_after_this
// Experimentally, standard mke2fs won't work on images smaller than 60k
if (nblocks < 60)
libbb: reduce the overhead of single parameter bb_error_msg() calls Back in 2007, commit 0c97c9d43707 ("'simple' error message functions by Loic Grenie") introduced bb_simple_perror_msg() to allow for a lower overhead call to bb_perror_msg() when only a string was being printed with no parameters. This saves space for some CPU architectures because it avoids the overhead of a call to a variadic function. However there has never been a simple version of bb_error_msg(), and since 2007 many new calls to bb_perror_msg() have been added that only take a single parameter and so could have been using bb_simple_perror_message(). This changeset introduces 'simple' versions of bb_info_msg(), bb_error_msg(), bb_error_msg_and_die(), bb_herror_msg() and bb_herror_msg_and_die(), and replaces all calls that only take a single parameter, or use something like ("%s", arg), with calls to the corresponding 'simple' version. Since it is likely that single parameter calls to the variadic functions may be accidentally reintroduced in the future a new debugging config option WARN_SIMPLE_MSG has been introduced. This uses some macro magic which will cause any such calls to generate a warning, but this is turned off by default to avoid use of the unpleasant macros in normal circumstances. This is a large changeset due to the number of calls that have been replaced. The only files that contain changes other than simple substitution of function calls are libbb.h, libbb/herror_msg.c, libbb/verror_msg.c and libbb/xfuncs_printf.c. In miscutils/devfsd.c, networking/udhcp/common.h and util-linux/mdev.c additonal macros have been added for logging so that single parameter and multiple parameter logging variants exist. The amount of space saved varies considerably by architecture, and was found to be as follows (for 'defconfig' using GCC 7.4): Arm: -92 bytes MIPS: -52 bytes PPC: -1836 bytes x86_64: -938 bytes Note that for the MIPS architecture only an exception had to be made disabling the 'simple' calls for 'udhcp' (in networking/udhcp/common.h) because it made these files larger on MIPS. Signed-off-by: James Byrne <james.byrne@origamienergy.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2019-07-02 15:05:03 +05:30
bb_simple_error_msg_and_die("need >= 60 blocks");
// How many reserved blocks?
if (reserved_percent > 50)
bb_error_msg_and_die("-%c is bad", 'm');
nreserved = (uint64_t)nblocks * reserved_percent / 100;
// N.B. killing e2fsprogs feature! Unused blocks don't account in calculations
nblocks_full = nblocks;
// If last block group is too small, nblocks may be decreased in order
// to discard it, and control returns here to recalculate some
// parameters.
// Note: blocksize and bytes_per_inode are never recalculated.
retry:
// N.B. a block group can have no more than blocks_per_group blocks
ngroups = div_roundup(nblocks - first_block, blocks_per_group);
group_desc_blocks = div_roundup(ngroups, blocksize / sizeof(*gd));
// TODO: reserved blocks must be marked as such in the bitmaps,
// or resulting filesystem is corrupt
if (ENABLE_FEATURE_MKFS_EXT2_RESERVED_GDT) {
/*
* From e2fsprogs: 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.
* We set it at 1024x the current filesystem size, or
* the upper block count limit (2^32), whichever is lower.
*/
uint32_t reserved_group_desc_blocks = 0xFFFFFFFF; // maximum block number
if (nblocks < reserved_group_desc_blocks / 1024)
reserved_group_desc_blocks = nblocks * 1024;
reserved_group_desc_blocks = div_roundup(reserved_group_desc_blocks - first_block, blocks_per_group);
reserved_group_desc_blocks = div_roundup(reserved_group_desc_blocks, blocksize / sizeof(*gd)) - group_desc_blocks;
if (reserved_group_desc_blocks > blocksize / sizeof(uint32_t))
reserved_group_desc_blocks = blocksize / sizeof(uint32_t);
//TODO: STORE_LE(sb->s_reserved_gdt_blocks, reserved_group_desc_blocks);
group_desc_blocks += reserved_group_desc_blocks;
}
{
// N.B. e2fsprogs does as follows!
uint32_t overhead, remainder;
// ninodes is the max number of inodes in this filesystem
uint32_t ninodes = ((uint64_t) nblocks_full * blocksize) / bytes_per_inode;
if (ninodes < EXT2_GOOD_OLD_FIRST_INO+1)
ninodes = EXT2_GOOD_OLD_FIRST_INO+1;
inodes_per_group = div_roundup(ninodes, ngroups);
// minimum number because the first EXT2_GOOD_OLD_FIRST_INO-1 are reserved
if (inodes_per_group < 16)
inodes_per_group = 16;
// a block group can't have more inodes than blocks
if (inodes_per_group > blocks_per_group)
inodes_per_group = blocks_per_group;
// adjust inodes per group so they completely fill the inode table blocks in the descriptor
inodes_per_group = (div_roundup(inodes_per_group * inodesize, blocksize) * blocksize) / inodesize;
// make sure the number of inodes per group is a multiple of 8
inodes_per_group &= ~7;
inode_table_blocks = div_roundup(inodes_per_group * inodesize, blocksize);
// to be useful, lost+found should occupy at least 2 blocks (but not exceeding 16*1024 bytes),
// and at most EXT2_NDIR_BLOCKS. So reserve these blocks right now
/* Or e2fsprogs comment verbatim (what does it mean?):
* Ensure that lost+found is at least 2 blocks, so we always
* test large empty blocks for big-block filesystems. */
lost_and_found_blocks = MIN(EXT2_NDIR_BLOCKS, 16 >> (blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE));
// the last group needs more attention: isn't it too small for possible overhead?
overhead = (has_super(ngroups - 1) ? (1/*sb*/ + group_desc_blocks) : 0) + 1/*bbmp*/ + 1/*ibmp*/ + inode_table_blocks;
remainder = (nblocks - first_block) % blocks_per_group;
////can't happen, nblocks >= 60 guarantees this
////if ((1 == ngroups)
//// && remainder
//// && (remainder < overhead + 1/* "/" */ + lost_and_found_blocks)
////) {
//// bb_error_msg_and_die("way small device");
////}
// Standard mke2fs uses 50. Looks like a bug in our calculation
// of "remainder" or "overhead" - we don't match standard mke2fs
// when we transition from one group to two groups
// (a bit after 8M image size), but it works for two->three groups
// transition (at 16M).
if (remainder && (remainder < overhead + 50)) {
//bb_error_msg("CHOP[%u]", remainder);
nblocks -= remainder;
goto retry;
}
}
if (nblocks_full - nblocks)
printf("warning: %u blocks unused\n\n", nblocks_full - nblocks);
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=%u\n"
"%u block groups\n"
"%u blocks per group, %u fragments per group\n"
"%u inodes per group"
, label
, blocksize, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE
, blocksize, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE
, inodes_per_group * ngroups, nblocks
, nreserved, reserved_percent
, first_block
, group_desc_blocks * (blocksize / (unsigned)sizeof(*gd)) * blocks_per_group
, ngroups
, blocks_per_group, blocks_per_group
, inodes_per_group
);
{
const char *fmt = "\nSuperblock backups stored on blocks:\n"
"\t%u";
pos = first_block;
for (i = 1; i < ngroups; i++) {
pos += blocks_per_group;
if (has_super(i)) {
printf(fmt, (unsigned)pos);
fmt = ", %u";
}
}
}
bb_putchar('\n');
if (option_mask32 & OPT_n) {
if (ENABLE_FEATURE_CLEAN_UP)
close(fd);
return EXIT_SUCCESS;
}
// TODO: 3/5 refuse if mounted
// TODO: 4/5 compat options
// TODO: 1/5 sanity checks
// TODO: 0/5 more verbose error messages
// TODO: 4/5 bigendianness: recheck, wait for ARM reporters
// TODO: 2/5 reserved GDT: how to mark but not allocate?
// TODO: 3/5 dir_index?
// fill the superblock
sb = xzalloc(1024);
STORE_LE(sb->s_rev_level, EXT2_DYNAMIC_REV); // revision 1 filesystem
STORE_LE(sb->s_magic, EXT2_SUPER_MAGIC);
STORE_LE(sb->s_inode_size, inodesize);
// set "Required extra isize" and "Desired extra isize" fields to 28
if (inodesize != sizeof(*inode)) {
STORE_LE(sb->s_min_extra_isize, 0x001c);
STORE_LE(sb->s_want_extra_isize, 0x001c);
}
STORE_LE(sb->s_first_ino, EXT2_GOOD_OLD_FIRST_INO);
STORE_LE(sb->s_log_block_size, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE);
STORE_LE(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 is 1, otherwise 0
STORE_LE(sb->s_first_data_block, first_block);
// block and inode bitmaps occupy no more than one block, so maximum number of blocks is
STORE_LE(sb->s_blocks_per_group, blocks_per_group);
STORE_LE(sb->s_frags_per_group, blocks_per_group);
// blocks
STORE_LE(sb->s_blocks_count, nblocks);
// reserve blocks for superuser
STORE_LE(sb->s_r_blocks_count, nreserved);
// ninodes
STORE_LE(sb->s_inodes_per_group, inodes_per_group);
STORE_LE(sb->s_inodes_count, inodes_per_group * ngroups);
STORE_LE(sb->s_free_inodes_count, inodes_per_group * ngroups - EXT2_GOOD_OLD_FIRST_INO);
// timestamps
timestamp = time(NULL);
STORE_LE(sb->s_mkfs_time, timestamp);
STORE_LE(sb->s_wtime, timestamp);
STORE_LE(sb->s_lastcheck, timestamp);
// misc. Values are chosen to match mke2fs 1.41.9
STORE_LE(sb->s_state, 1); // TODO: what's 1?
STORE_LE(sb->s_creator_os, EXT2_OS_LINUX);
STORE_LE(sb->s_checkinterval, 24*60*60 * 180); // 180 days
STORE_LE(sb->s_errors, EXT2_ERRORS_DEFAULT);
// mke2fs 1.41.9 also sets EXT3_FEATURE_COMPAT_RESIZE_INODE
// and if >= 0.5GB, EXT3_FEATURE_RO_COMPAT_LARGE_FILE.
// we use values which match "mke2fs -O ^resize_inode":
// in this case 1.41.9 never sets EXT3_FEATURE_RO_COMPAT_LARGE_FILE.
STORE_LE(sb->s_feature_compat, EXT2_FEATURE_COMPAT_SUPP
| (EXT2_FEATURE_COMPAT_RESIZE_INO * ENABLE_FEATURE_MKFS_EXT2_RESERVED_GDT)
| (EXT2_FEATURE_COMPAT_DIR_INDEX * ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX)
);
STORE_LE(sb->s_feature_incompat, EXT2_FEATURE_INCOMPAT_FILETYPE);
STORE_LE(sb->s_feature_ro_compat, EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER);
STORE_LE(sb->s_flags, EXT2_FLAGS_UNSIGNED_HASH * ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX);
generate_uuid(sb->s_uuid);
if (ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX) {
STORE_LE(sb->s_def_hash_version, EXT2_HASH_HALF_MD4);
generate_uuid((uint8_t *)sb->s_hash_seed);
}
/*
* 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
* kludgy hack of using the UUID to derive a random jitter value.
*/
STORE_LE(sb->s_max_mnt_count,
EXT2_DFL_MAX_MNT_COUNT
+ (sb->s_uuid[ARRAY_SIZE(sb->s_uuid)-1] % EXT2_DFL_MAX_MNT_COUNT));
// write the label
safe_strncpy((char *)sb->s_volume_name, label, sizeof(sb->s_volume_name));
// calculate filesystem skeleton structures
gd = xzalloc(group_desc_blocks * blocksize);
buf = xmalloc(blocksize);
sb->s_free_blocks_count = 0;
for (i = 0, pos = first_block, n = nblocks - first_block;
i < ngroups;
i++, pos += blocks_per_group, n -= blocks_per_group
) {
uint32_t overhead = pos + (has_super(i) ? (1/*sb*/ + group_desc_blocks) : 0);
uint32_t free_blocks;
// fill group descriptors
STORE_LE(gd[i].bg_block_bitmap, overhead + 0);
STORE_LE(gd[i].bg_inode_bitmap, overhead + 1);
STORE_LE(gd[i].bg_inode_table, overhead + 2);
overhead = overhead - pos + 1/*bbmp*/ + 1/*ibmp*/ + inode_table_blocks;
gd[i].bg_free_inodes_count = inodes_per_group;
//STORE_LE(gd[i].bg_used_dirs_count, 0);
// N.B. both "/" and "/lost+found" are within the first block group
// "/" occupies 1 block, "/lost+found" occupies lost_and_found_blocks...
if (0 == i) {
// ... thus increased overhead for the first block group ...
overhead += 1 + lost_and_found_blocks;
// ... and 2 used directories
STORE_LE(gd[i].bg_used_dirs_count, 2);
// well known reserved inodes belong to the first block too
gd[i].bg_free_inodes_count -= EXT2_GOOD_OLD_FIRST_INO;
}
// cache free block count of the group
free_blocks = (n < blocks_per_group ? n : blocks_per_group) - overhead;
// mark preallocated blocks as allocated
//bb_error_msg("ALLOC: [%u][%u][%u]", blocksize, overhead, blocks_per_group - (free_blocks + overhead));
allocate(buf, blocksize,
// reserve "overhead" blocks
overhead,
// mark unused trailing blocks
blocks_per_group - (free_blocks + overhead)
);
// dump block bitmap
PUT((uint64_t)(FETCH_LE32(gd[i].bg_block_bitmap)) * blocksize, buf, blocksize);
STORE_LE(gd[i].bg_free_blocks_count, free_blocks);
// mark preallocated inodes as allocated
allocate(buf, blocksize,
// mark reserved inodes
inodes_per_group - gd[i].bg_free_inodes_count,
// mark unused trailing inodes
blocks_per_group - inodes_per_group
);
// dump inode bitmap
//PUT((uint64_t)(FETCH_LE32(gd[i].bg_block_bitmap)) * blocksize, buf, blocksize);
//but it's right after block bitmap, so we can just:
xwrite(fd, buf, blocksize);
STORE_LE(gd[i].bg_free_inodes_count, gd[i].bg_free_inodes_count);
// count overall free blocks
sb->s_free_blocks_count += free_blocks;
}
STORE_LE(sb->s_free_blocks_count, sb->s_free_blocks_count);
// dump filesystem skeleton structures
// printf("Writing superblocks and filesystem accounting information: ");
for (i = 0, pos = first_block; i < ngroups; i++, pos += blocks_per_group) {
// dump superblock and group descriptors and their backups
if (has_super(i)) {
// N.B. 1024 byte blocks are special
PUT(((uint64_t)pos * blocksize) + ((0 == i && 1024 != blocksize) ? 1024 : 0),
sb, 1024);
PUT(((uint64_t)pos * blocksize) + blocksize,
gd, group_desc_blocks * blocksize);
}
}
// zero boot sectors
memset(buf, 0, blocksize);
// Disabled: standard mke2fs doesn't do this, and
// on SPARC this destroys Sun disklabel.
// Users who need/want zeroing can easily do it with dd.
//PUT(0, buf, 1024); // N.B. 1024 <= blocksize, so buf[0..1023] contains zeros
// zero inode tables
for (i = 0; i < ngroups; ++i)
for (n = 0; n < inode_table_blocks; ++n)
PUT((uint64_t)(FETCH_LE32(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);
STORE_LE(inode->i_mtime, timestamp);
STORE_LE(inode->i_atime, timestamp);
STORE_LE(inode->i_ctime, timestamp);
STORE_LE(inode->i_size, blocksize);
// inode->i_blocks stores the number of 512 byte data blocks
// (512, because it goes directly to struct stat without scaling)
STORE_LE(inode->i_blocks, blocksize / 512);
// dump root dir inode
STORE_LE(inode->i_links_count, 3); // "/.", "/..", "/lost+found/.." point to this inode
STORE_LE(inode->i_block[0], FETCH_LE32(gd[0].bg_inode_table) + inode_table_blocks);
PUT(((uint64_t)FETCH_LE32(gd[0].bg_inode_table) * blocksize) + (EXT2_ROOT_INO-1) * inodesize,
buf, inodesize);
// 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_size, lost_and_found_blocks * blocksize);
STORE_LE(inode->i_blocks, (lost_and_found_blocks * blocksize) / 512);
n = FETCH_LE32(inode->i_block[0]) + 1;
for (i = 0; i < lost_and_found_blocks; ++i)
STORE_LE(inode->i_block[i], i + n); // use next block
//bb_error_msg("LAST BLOCK USED[%u]", i + n);
PUT(((uint64_t)FETCH_LE32(gd[0].bg_inode_table) * blocksize) + (EXT2_GOOD_OLD_FIRST_INO-1) * inodesize,
buf, inodesize);
// dump directories
memset(buf, 0, blocksize);
dir = (struct ext2_dir *)buf;
// dump 2nd+ blocks of "/lost+found"
STORE_LE(dir->rec_len1, blocksize); // e2fsck 1.41.4 compat (1.41.9 does not need this)
for (i = 1; i < lost_and_found_blocks; ++i)
PUT((uint64_t)(FETCH_LE32(gd[0].bg_inode_table) + inode_table_blocks + 1+i) * blocksize,
buf, blocksize);
// dump 1st block of "/lost+found"
STORE_LE(dir->inode1, EXT2_GOOD_OLD_FIRST_INO);
STORE_LE(dir->rec_len1, 12);
STORE_LE(dir->name_len1, 1);
STORE_LE(dir->file_type1, EXT2_FT_DIR);
dir->name1[0] = '.';
STORE_LE(dir->inode2, EXT2_ROOT_INO);
STORE_LE(dir->rec_len2, blocksize - 12);
STORE_LE(dir->name_len2, 2);
STORE_LE(dir->file_type2, EXT2_FT_DIR);
dir->name2[0] = '.'; dir->name2[1] = '.';
PUT((uint64_t)(FETCH_LE32(gd[0].bg_inode_table) + inode_table_blocks + 1) * blocksize, buf, blocksize);
// dump root dir block
STORE_LE(dir->inode1, EXT2_ROOT_INO);
STORE_LE(dir->rec_len2, 12);
STORE_LE(dir->inode3, EXT2_GOOD_OLD_FIRST_INO);
STORE_LE(dir->rec_len3, blocksize - 12 - 12);
STORE_LE(dir->name_len3, 10);
STORE_LE(dir->file_type3, EXT2_FT_DIR);
strcpy(dir->name3, "lost+found");
PUT((uint64_t)(FETCH_LE32(gd[0].bg_inode_table) + inode_table_blocks + 0) * blocksize, buf, blocksize);
// cleanup
if (ENABLE_FEATURE_CLEAN_UP) {
free(buf);
free(gd);
free(sb);
}
xclose(fd);
return EXIT_SUCCESS;
}