Путь: Toys/Pending, команды версии: Ver.4 Ver.9 Комментарии в файле mke2fs.c : Команд: 5 mke2fs
mke2fs_journal
mke2fs_gen
mke2fs_label
mke2fs_extended
Исходный текст в файле mke2fs.c #define FOR_mke2fs
#include "toys.h"
GLOBALS(
// Command line arguments.
long blocksize;
long bytes_per_inode;
long inodes; // Total inodes in filesystem.
long reserved_percent; // Integer precent of space to reserve for root.
char *gendir; // Where to read dirtree from.
// Internal data.
struct dirtree *dt; // Tree of files to copy into the new filesystem.
unsigned treeblocks; // Blocks used by dt
unsigned treeinodes; // Inodes used by dt
unsigned blocks; // Total blocks in the filesystem.
unsigned freeblocks; // Free blocks in the filesystem.
unsigned inodespg; // Inodes per group
unsigned groups; // Total number of block groups.
unsigned blockbits; // Bits per block. (Also blocks per group.)
// For gene2fs
unsigned nextblock; // Next data block to allocate
unsigned nextgroup; // Next group we'll be allocating from
int fsfd; // File descriptor of filesystem (to output to).
)
// Stuff defined in linux/ext2_fs.h
#define EXT2_SUPER_MAGIC 0xEF53
struct ext2_superblock {
uint32_t inodes_count; // Inodes count
uint32_t blocks_count; // Blocks count
uint32_t r_blocks_count; // Reserved blocks count
uint32_t free_blocks_count; // Free blocks count
uint32_t free_inodes_count; // Free inodes count
uint32_t first_data_block; // First Data Block
uint32_t log_block_size; // Block size
uint32_t log_frag_size; // Fragment size
uint32_t blocks_per_group; // Blocks per group
uint32_t frags_per_group; // Fragments per group
uint32_t inodes_per_group; // Inodes per group
uint32_t mtime; // Mount time
uint32_t wtime; // Write time
uint16_t mnt_count; // Mount count
uint16_t max_mnt_count; // Maximal mount count
uint16_t magic; // Magic signature
uint16_t state; // File system state
uint16_t errors; // Behaviour when detecting errors
uint16_t minor_rev_level; // minor revision level
uint32_t lastcheck; // time of last check
uint32_t checkinterval; // max. time between checks
uint32_t creator_os; // OS
uint32_t rev_level; // Revision level
uint16_t def_resuid; // Default uid for reserved blocks
uint16_t def_resgid; // Default gid for reserved blocks
uint32_t first_ino; // First non-reserved inode
uint16_t inode_size; // size of inode structure
uint16_t block_group_nr; // block group # of this superblock
uint32_t feature_compat; // compatible feature set
uint32_t feature_incompat; // incompatible feature set
uint32_t feature_ro_compat; // readonly-compatible feature set
char uuid[16]; // 128-bit uuid for volume
char volume_name[16]; // volume name
char last_mounted[64]; // directory where last mounted
uint32_t alg_usage_bitmap; // For compression
// For EXT2_COMPAT_PREALLOC
uint8_t prealloc_blocks; // Nr of blocks to try to preallocate
uint8_t prealloc_dir_blocks; //Nr to preallocate for dirs
uint16_t padding1;
// For EXT3_FEATURE_COMPAT_HAS_JOURNAL
uint8_t journal_uuid[16]; // uuid of journal superblock
uint32_t journal_inum; // inode number of journal file
uint32_t journal_dev; // device number of journal file
uint32_t last_orphan; // start of list of inodes to delete
uint32_t hash_seed[4]; // HTREE hash seed
uint8_t def_hash_version; // Default hash version to use
uint8_t padding2[3];
uint32_t default_mount_opts;
uint32_t first_meta_bg; // First metablock block group
uint32_t mkfs_time; // Creation timestamp
uint32_t jnl_blocks[17]; // Backup of journal inode
// uint32_t reserved[172]; // Padding to the end of the block
};
struct ext2_group
{
uint32_t block_bitmap; // Block number of block bitmap
uint32_t inode_bitmap; // Block number of inode bitmap
uint32_t inode_table; // Block number of inode table
uint16_t free_blocks_count; // How many free blocks in this group?
uint16_t free_inodes_count; // How many free inodes in this group?
uint16_t used_dirs_count; // How many directories?
uint16_t reserved[7]; // pad to 32 bytes
};
struct ext2_dentry {
uint32_t inode; // Inode number
uint16_t rec_len; // Directory entry length
uint8_t name_len; // Name length
uint8_t file_type;
char name[0]; // File name
};
struct ext2_inode {
uint16_t mode; // File mode
uint16_t uid; // Low 16 bits of Owner Uid
uint32_t size; // Size in bytes
uint32_t atime; // Access time
uint32_t ctime; // Creation time
uint32_t mtime; // Modification time
uint32_t dtime; // Deletion Time
uint16_t gid; // Low 16 bits of Group Id
uint16_t links_count; // Links count
uint32_t blocks; // Blocks count
uint32_t flags; // File flags
uint32_t reserved1;
uint32_t block[15]; // Pointers to blocks
uint32_t generation; // File version (for NFS)
uint32_t file_acl; // File ACL
uint32_t dir_acl; // Directory ACL (or top bits of file length)
uint32_t faddr; // Last block in file
uint8_t frag; // Fragment number
uint8_t fsize; // Fragment size
uint16_t pad1;
uint16_t uid_high; // High bits of uid
uint16_t gid_high; // High bits of gid
uint32_t reserved2;
};
#define EXT2_FEATURE_COMPAT_DIR_PREALLOC 0x0001
#define EXT2_FEATURE_COMPAT_IMAGIC_INODES 0x0002
#define EXT3_FEATURE_COMPAT_HAS_JOURNAL 0x0004
#define EXT2_FEATURE_COMPAT_EXT_ATTR 0x0008
#define EXT2_FEATURE_COMPAT_RESIZE_INO 0x0010
#define EXT2_FEATURE_COMPAT_DIR_INDEX 0x0020
#define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001
#define EXT2_FEATURE_RO_COMPAT_LARGE_FILE 0x0002
#define EXT2_FEATURE_RO_COMPAT_BTREE_DIR 0x0004
#define EXT2_FEATURE_INCOMPAT_COMPRESSION 0x0001
#define EXT2_FEATURE_INCOMPAT_FILETYPE 0x0002
#define EXT3_FEATURE_INCOMPAT_RECOVER 0x0004
#define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV 0x0008
#define EXT2_FEATURE_INCOMPAT_META_BG 0x0010
#define EXT2_NAME_LEN 255
// Ext2 directory file types. Only the low 3 bits are used. The
// other bits are reserved for now.
enum {
EXT2_FT_UNKNOWN,
EXT2_FT_REG_FILE,
EXT2_FT_DIR,
EXT2_FT_CHRDEV,
EXT2_FT_BLKDEV,
EXT2_FT_FIFO,
EXT2_FT_SOCK,
EXT2_FT_SYMLINK,
EXT2_FT_MAX
};
#define INODES_RESERVED 10
static uint32_t div_round_up(uint32_t a, uint32_t b)
{
uint32_t c = a/b;
if (a%b) c++;
return c;
}
// Calculate data blocks plus index blocks needed to hold a file.
static uint32_t file_blocks_used(uint64_t size, uint32_t *blocklist)
{
uint32_t dblocks = (uint32_t)((size+(TT.blocksize-1))/TT.blocksize);
uint32_t idx=TT.blocksize/4, iblocks=0, diblocks=0, tiblocks=0;
// Fill out index blocks in inode.
if (blocklist) {
int i;
// Direct index blocks
for (i=0; i<13 && i<dblocks; i++) blocklist[i] = i;
// Singly indirect index blocks
if (dblocks > 13+idx) blocklist[13] = 13+idx;
// Doubly indirect index blocks
idx = 13 + idx + (idx*idx);
if (dblocks > idx) blocklist[14] = idx;
return 0;
}
// Account for direct, singly, doubly, and triply indirect index blocks
if (dblocks > 12) {
iblocks = ((dblocks-13)/idx)+1;
if (iblocks > 1) {
diblocks = ((iblocks-2)/idx)+1;
if (diblocks > 1)
tiblocks = ((diblocks-2)/idx)+1;
}
}
return dblocks + iblocks + diblocks + tiblocks;
}
// Use the parent pointer to iterate through the tree non-recursively.
static struct dirtree *treenext(struct dirtree *this)
{
while (this && !this->next) this = this->parent;
if (this) this = this->next;
return this;
}
// Recursively calculate the number of blocks used by each inode in the tree.
// Returns blocks used by this directory, assigns bytes used to *size.
// Writes total block count to TT.treeblocks and inode count to TT.treeinodes.
static long check_treesize(struct dirtree *that, off_t *size)
{
long blocks;
while (that) {
*size += sizeof(struct ext2_dentry) + strlen(that->name);
if (that->child)
that->st.st_blocks = check_treesize(that->child, &that->st.st_size);
else if (S_ISREG(that->st.st_mode)) {
that->st.st_blocks = file_blocks_used(that->st.st_size, 0);
TT.treeblocks += that->st.st_blocks;
}
that = that->next;
}
TT.treeblocks += blocks = file_blocks_used(*size, 0);
TT.treeinodes++;
return blocks;
}
// Calculate inode numbers and link counts.
//
// To do this right I need to copy the tree and sort it, but here's a really
// ugly n^2 way of dealing with the problem that doesn't scale well to large
// numbers of files (> 100,000) but can be done in very little code.
// This rewrites inode numbers to their final values, allocating depth first.
static void check_treelinks(struct dirtree *tree)
{
struct dirtree *current=tree, *that;
long inode = INODES_RESERVED;
while (current) {
++inode;
// Since we can't hardlink to directories, we know their link count.
if (S_ISDIR(current->st.st_mode)) current->st.st_nlink = 2;
else {
dev_t new = current->st.st_dev;
if (!new) continue;
// Look for other copies of current node
current->st.st_nlink = 0;
for (that = tree; that; that = treenext(that)) {
if (same_file(current, that)) {
current->st.st_nlink++;
current->st.st_ino = inode;
}
}
}
current->st.st_ino = inode;
current = treenext(current);
}
}
// Calculate inodes per group from total inodes.
static uint32_t get_inodespg(uint32_t inodes)
{
uint32_t temp;
// Round up to fill complete inode blocks.
temp = (inodes + TT.groups - 1) / TT.groups;
inodes = TT.blocksize/sizeof(struct ext2_inode);
return ((temp + inodes - 1)/inodes)*inodes;
}
// Fill out superblock and TT structures.
static void init_superblock(struct ext2_superblock *sb)
{
uint32_t temp;
// Set log_block_size and log_frag_size.
for (temp = 0; temp < 4; temp++) if (TT.blocksize == 1024<<temp) break;
if (temp==4) error_exit("bad blocksize");
sb->log_block_size = sb->log_frag_size = SWAP_LE32(temp);
// Fill out blocks_count, r_blocks_count, first_data_block
sb->blocks_count = SWAP_LE32(TT.blocks);
sb->free_blocks_count = SWAP_LE32(TT.freeblocks);
temp = (TT.blocks * (uint64_t)TT.reserved_percent) / 100;
sb->r_blocks_count = SWAP_LE32(temp);
sb->first_data_block = SWAP_LE32(TT.blocksize == 1024 ? 1 : 0);
// Set blocks_per_group and frags_per_group, which is the size of an
// allocation bitmap that fits in one block (I.E. how many bits per block)?
sb->blocks_per_group = sb->frags_per_group = SWAP_LE32(TT.blockbits);
// Set inodes_per_group and total inodes_count
sb->inodes_per_group = SWAP_LE32(TT.inodespg);
sb->inodes_count = SWAP_LE32(TT.inodespg * TT.groups);
// Determine free inodes.
temp = TT.inodespg*TT.groups - INODES_RESERVED;
if (temp < TT.treeinodes) error_exit("Not enough inodes.\n");
sb->free_inodes_count = SWAP_LE32(temp - TT.treeinodes);
// Fill out the rest of the superblock.
sb->max_mnt_count=0xFFFF;
sb->wtime = sb->lastcheck = sb->mkfs_time = SWAP_LE32(time(NULL));
sb->magic = SWAP_LE32(0xEF53);
sb->state = sb->errors = SWAP_LE16(1);
sb->rev_level = SWAP_LE32(1);
sb->first_ino = SWAP_LE32(INODES_RESERVED+1);
sb->inode_size = SWAP_LE16(sizeof(struct ext2_inode));
sb->feature_incompat = SWAP_LE32(EXT2_FEATURE_INCOMPAT_FILETYPE);
sb->feature_ro_compat = SWAP_LE32(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER);
create_uuid(sb->uuid);
// TODO If we're called as mke3fs or mkfs.ext3, do a journal.
//if (strchr(toys.which->name,'3'))
// sb->feature_compat |= SWAP_LE32(EXT3_FEATURE_COMPAT_HAS_JOURNAL);
}
// Does this group contain a superblock backup (and group descriptor table)?
static int is_sb_group(uint32_t group)
{
int i;
// Superblock backups are on groups 0, 1, and powers of 3, 5, and 7.
if(!group || group==1) return 1;
for (i=3; i<9; i+=2) {
int j = i;
while (j<group) j*=i;
if (j==group) return 1;
}
return 0;
}
// Number of blocks used in group by optional superblock/group list backup.
static int group_superblock_overhead(uint32_t group)
{
int used;
if (!is_sb_group(group)) return 0;
// How many blocks does the group descriptor table take up?
used = TT.groups * sizeof(struct ext2_group);
used += TT.blocksize - 1;
used /= TT.blocksize;
// Plus the superblock itself.
used++;
// And a corner case.
if (!group && TT.blocksize == 1024) used++;
return used;
}
// Number of blocks used in group to store superblock/group/inode list
static int group_overhead(uint32_t group)
{
// Return superblock backup overhead (if any), plus block/inode
// allocation bitmaps, plus inode tables.
return group_superblock_overhead(group) + 2 + get_inodespg(TT.inodespg)
/ (TT.blocksize/sizeof(struct ext2_inode));
}
// In bitmap "array" set "len" bits starting at position "start" (from 0).
static void bits_set(char *array, int start, int len)
{
while(len) {
if ((start&7) || len<8) {
array[start/8]|=(1<<(start&7));
start++;
len--;
} else {
array[start/8]=255;
start+=8;
len-=8;
}
}
}
// Seek past len bytes (to maintain sparse file), or write zeroes if output
// not seekable
static void put_zeroes(int len)
{
if(-1 == lseek(TT.fsfd, len, SEEK_SET)) {
memset(toybuf, 0, sizeof(toybuf));
while (len) {
int out = len > sizeof(toybuf) ? sizeof(toybuf) : len;
xwrite(TT.fsfd, toybuf, out);
len -= out;
}
}
}
// Fill out an inode structure from struct stat info in dirtree.
static void fill_inode(struct ext2_inode *in, struct dirtree *that)
{
uint32_t fbu[15];
int temp;
file_blocks_used(that->st.st_size, fbu);
// If that inode needs data blocks allocated to it.
if (that->st.st_size) {
int i, group = TT.nextblock/TT.blockbits;
// TODO: teach this about indirect blocks.
for (i=0; i<15; i++) {
// If we just jumped into a new group, skip group overhead blocks.
while (group >= TT.nextgroup)
TT.nextblock += group_overhead(TT.nextgroup++);
}
}
// TODO : S_ISREG/DIR/CHR/BLK/FIFO/LNK/SOCK(m)
in->mode = SWAP_LE32(that->st.st_mode);
in->uid = SWAP_LE16(that->st.st_uid & 0xFFFF);
in->uid_high = SWAP_LE16(that->st.st_uid >> 16);
in->gid = SWAP_LE16(that->st.st_gid & 0xFFFF);
in->gid_high = SWAP_LE16(that->st.st_gid >> 16);
in->size = SWAP_LE32(that->st.st_size & 0xFFFFFFFF);
// Contortions to make the compiler not generate a warning for x>>32
// when x is 32 bits. The optimizer should clean this up.
if (sizeof(that->st.st_size) > 4) temp = 32;
else temp = 0;
if (temp) in->dir_acl = SWAP_LE32(that->st.st_size >> temp);
in->atime = SWAP_LE32(that->st.st_atime);
in->ctime = SWAP_LE32(that->st.st_ctime);
in->mtime = SWAP_LE32(that->st.st_mtime);
in->links_count = SWAP_LE16(that->st.st_nlink);
in->blocks = SWAP_LE32(that->st.st_blocks);
// in->faddr
}
// Works like an archiver.
// The first argument is the name of the file to create. If it already
// exists, that size will be used.
void mke2fs_main(void)
{
int i, temp;
off_t length;
uint32_t usedblocks, usedinodes, dtbblk;
struct dirtree *dti, *dtb;
struct ext2_superblock sb;
// Handle command line arguments.
if (toys.optargs[1]) {
sscanf(toys.optargs[1], "%u", &TT.blocks);
temp = O_RDWR|O_CREAT;
} else temp = O_RDWR;
if (!TT.reserved_percent) TT.reserved_percent = 5;
// TODO: Check if filesystem is mounted here
// For mke?fs, open file. For gene?fs, create file.
TT.fsfd = xcreate(*toys.optargs, temp, 0777);
// Determine appropriate block size and block count from file length.
// (If no length, default to 4k. They can override it on the cmdline.)
length = fdlength(TT.fsfd);
if (!TT.blocksize) TT.blocksize = (length && length < 1<<29) ? 1024 : 4096;
TT.blockbits = 8*TT.blocksize;
if (!TT.blocks) TT.blocks = length/TT.blocksize;
// Collect gene2fs list or lost+found, calculate requirements.
if (TT.gendir) {
strncpy(toybuf, TT.gendir, sizeof(toybuf));
dti = dirtree_read(toybuf, dirtree_notdotdot);
} else {
dti = xzalloc(sizeof(struct dirtree)+11);
strcpy(dti->name, "lost+found");
dti->st.st_mode = S_IFDIR|0755;
dti->st.st_ctime = dti->st.st_mtime = time(NULL);
}
// Add root directory inode. This is iterated through for when finding
// blocks, but not when finding inodes. The tree's parent pointers don't
// point back into this.
dtb = xzalloc(sizeof(struct dirtree)+1);
dtb->st.st_mode = S_IFDIR|0755;
dtb->st.st_ctime = dtb->st.st_mtime = time(NULL);
dtb->child = dti;
// Figure out how much space is used by preset files
length = check_treesize(dtb, &(dtb->st.st_size));
check_treelinks(dtb);
// Figure out how many total inodes we need.
if (!TT.inodes) {
if (!TT.bytes_per_inode) TT.bytes_per_inode = 8192;
TT.inodes = (TT.blocks * (uint64_t)TT.blocksize) / TT.bytes_per_inode;
}
// If we're generating a filesystem and have no idea how many blocks it
// needs, start with a minimal guess, find the overhead of that many
// groups, and loop until this is enough groups to store this many blocks.
if (!TT.blocks) TT.groups = (TT.treeblocks/TT.blockbits)+1;
else TT.groups = div_round_up(TT.blocks, TT.blockbits);
for (;;) {
temp = TT.treeblocks;
for (i = 0; i<TT.groups; i++) temp += group_overhead(i);
if (TT.blocks) {
if (TT.blocks < temp) error_exit("Not enough space.\n");
break;
}
if (temp <= TT.groups * TT.blockbits) {
TT.blocks = temp;
break;
}
TT.groups++;
}
TT.freeblocks = TT.blocks - temp;
// Now we know all the TT data, initialize superblock structure.
init_superblock(&sb);
// Start writing. Skip the first 1k to avoid the boot sector (if any).
put_zeroes(1024);
// Loop through block groups, write out each one.
dtbblk = usedblocks = usedinodes = 0;
for (i=0; i<TT.groups; i++) {
struct ext2_inode *in = (struct ext2_inode *)toybuf;
uint32_t start, itable, used, end;
int j, slot;
// Where does this group end?
end = TT.blockbits;
if ((i+1)*TT.blockbits > TT.blocks) end = TT.blocks & (TT.blockbits-1);
// Blocks used by inode table
itable = (TT.inodespg*sizeof(struct ext2_inode))/TT.blocksize;
// If a superblock goes here, write it out.
start = group_superblock_overhead(i);
if (start) {
struct ext2_group *bg = (struct ext2_group *)toybuf;
int treeblocks = TT.treeblocks, treeinodes = TT.treeinodes;
sb.block_group_nr = SWAP_LE16(i);
// Write superblock and pad it up to block size
xwrite(TT.fsfd, &sb, sizeof(struct ext2_superblock));
temp = TT.blocksize - sizeof(struct ext2_superblock);
if (!i && TT.blocksize > 1024) temp -= 1024;
memset(toybuf, 0, TT.blocksize);
xwrite(TT.fsfd, toybuf, temp);
// Loop through groups to write group descriptor table.
for(j=0; j<TT.groups; j++) {
// Figure out what sector this group starts in.
used = group_superblock_overhead(j);
// Find next array slot in this block (flush block if full).
slot = j % (TT.blocksize/sizeof(struct ext2_group));
if (!slot) {
if (j) xwrite(TT.fsfd, bg, TT.blocksize);
memset(bg, 0, TT.blocksize);
}
// How many free inodes in this group?
temp = TT.inodespg;
if (!i) temp -= INODES_RESERVED;
if (temp > treeinodes) {
treeinodes -= temp;
temp = 0;
} else {
temp -= treeinodes;
treeinodes = 0;
}
bg[slot].free_inodes_count = SWAP_LE16(temp);
// How many free blocks in this group?
temp = TT.inodespg/(TT.blocksize/sizeof(struct ext2_inode)) + 2;
temp = end-used-temp;
if (temp > treeblocks) {
treeblocks -= temp;
temp = 0;
} else {
temp -= treeblocks;
treeblocks = 0;
}
bg[slot].free_blocks_count = SWAP_LE32(temp);
// Fill out rest of group structure
used += j*TT.blockbits;
bg[slot].block_bitmap = SWAP_LE32(used++);
bg[slot].inode_bitmap = SWAP_LE32(used++);
bg[slot].inode_table = SWAP_LE32(used);
bg[slot].used_dirs_count = 0; // (TODO)
}
xwrite(TT.fsfd, bg, TT.blocksize);
}
// Now write out stuff that every block group has.
// Write block usage bitmap
start += 2 + itable;
memset(toybuf, 0, TT.blocksize);
bits_set(toybuf, 0, start);
bits_set(toybuf, end, TT.blockbits-end);
temp = TT.treeblocks - usedblocks;
if (temp) {
if (end-start > temp) temp = end-start;
bits_set(toybuf, start, temp);
}
xwrite(TT.fsfd, toybuf, TT.blocksize);
// Write inode bitmap
memset(toybuf, 0, TT.blocksize);
j = 0;
if (!i) bits_set(toybuf, 0, j = INODES_RESERVED);
bits_set(toybuf, TT.inodespg, slot = TT.blockbits-TT.inodespg);
temp = TT.treeinodes - usedinodes;
if (temp) {
if (slot-j > temp) temp = slot-j;
bits_set(toybuf, j, temp);
}
xwrite(TT.fsfd, toybuf, TT.blocksize);
// Write inode table for this group (TODO)
for (j = 0; j<TT.inodespg; j++) {
slot = j % (TT.blocksize/sizeof(struct ext2_inode));
if (!slot) {
if (j) xwrite(TT.fsfd, in, TT.blocksize);
memset(in, 0, TT.blocksize);
}
if (!i && j<INODES_RESERVED) {
// Write root inode
if (j == 2) fill_inode(in+slot, dtb);
} else if (dti) {
fill_inode(in+slot, dti);
dti = treenext(dti);
}
}
xwrite(TT.fsfd, in, TT.blocksize);
while (dtb) {
// TODO write index data block
// TODO write root directory data block
// TODO write directory data block
// TODO write file data block
put_zeroes(TT.blocksize);
start++;
if (start == end) break;
}
// Write data blocks (TODO)
put_zeroes((end-start) * TT.blocksize);
}
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