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mkfs_ext2: fixes for huge filesystems

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function                                             old     new   delta
mkfs_ext2_main                                      2145    2617    +472
div_roundup                                           15      35     +20
packed_usage                                       26792   26776     -16

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2009-10-18 18:05:27 +02:00
parent 77da1cae94
commit f9d3a91a89
2 changed files with 44 additions and 24 deletions
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2
include/usage.h
View File

@ -2724,7 +2724,7 @@
"[-L LABEL] " \
"[-n] " \
/* "[-M last-mounted-directory] [-S] [-T filesystem-type] " */ \
"DEVICE [BLK_COUNT]"
"DEVICE [KBYTES]"
#define mkfs_ext2_full_usage "\n" \
"\n -b BLK_SIZE Block size in bytes" \
/* "\n -c Check for bad blocks before creating" */ \

66
util-linux/mkfs_ext2.c
View File

@ -70,7 +70,11 @@ static unsigned int_log2(unsigned arg)
// taken from mkfs_minix.c. libbb candidate?
static unsigned div_roundup(uint32_t size, uint32_t n)
{
return (size + n-1) / 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)
@ -161,6 +165,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
unsigned i, pos, n;
unsigned bs, blocksize, blocksize_log2;
unsigned nreserved = 5;
unsigned long long nblocks_ull;
uint32_t nblocks;
uint32_t ngroups;
unsigned bytes_per_inode;
@ -179,23 +184,13 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
struct ext2_dir *dir;
uint8_t *buf;
bs = EXT2_MIN_BLOCK_SIZE;
opt_complementary = "-1:b+:m+:i+";
opts = getopt32(argv, "cl:b:f:i:I:J:G:N:m:o:g:L:M:O:r:E:T:U:jnqvFS",
NULL, &bs, NULL, &bytes_per_inode, NULL, NULL, NULL, NULL,
&nreserved, NULL, NULL, &label, NULL, NULL, NULL, NULL, NULL, NULL);
argv += optind; // argv[0] -- device
// block size minimax, block size is a multiple of minimum
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("-%c is bad", 'b');
}
// reserved blocks count
// reserved blocks percentage
if (nreserved > 50)
bb_error_msg_and_die("-%c is bad", 'm');
@ -210,6 +205,42 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
if (find_mount_point(argv[0], 0))
bb_error_msg_and_die("can't format mounted filesystem");
// open the device, get size in kbytes
xmove_fd(xopen3(argv[0], O_WRONLY | O_CREAT, 0666), fd);
if (argv[1]) {
nblocks_ull = xatoull(argv[1]);
} else {
nblocks_ull = (uoff_t)xlseek(fd, 0, SEEK_END) / 1024;
}
// block size is a multiple of 1024
blocksize = 1024;
if (nblocks_ull >= 512*1024) // mke2fs 1.41.9 compat
blocksize = 4096;
if (EXT2_MAX_BLOCK_SIZE > 4096) {
// nblocks_ull >> 22 == size in 4gigabyte chunks.
// if it is >= 16k gigs, blocksize must be increased.
// Try "mke2fs -F image_std $((16 * 1024*1024*1024))"
while ((nblocks_ull >> 22) >= blocksize)
blocksize *= 2;
}
if (opts & 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);
}
blocksize_log2 = int_log2(blocksize);
nblocks_ull >>= (blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE);
// nblocks: the total number of blocks in the filesystem
nblocks = nblocks_ull;
if (nblocks != nblocks_ull)
bb_error_msg_and_die("block count doesn't fit in 32 bits");
if (nblocks < 8)
bb_error_msg_and_die("need >= 8 blocks");
// TODO: 5?/5 WE MUST NOT DEPEND ON WHETHER DEVICE IS /dev/zero 'ed OR NOT
// TODO: 3/5 refuse if mounted
// TODO: 4/5 compat options
@ -226,7 +257,6 @@ 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;
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
@ -261,18 +291,8 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
*/
sb->s_max_mnt_count += sb->s_uuid[ARRAY_SIZE(sb->s_uuid)-1] % EXT2_DFL_MAX_MNT_COUNT;
// open the device, get number of blocks
xmove_fd(xopen3(argv[0], O_WRONLY | O_CREAT, 0666), fd);
if (argv[1]) {
nblocks = xatou(argv[1]);
} else {
nblocks = (uoff_t)xlseek(fd, 0, SEEK_END) >> blocksize_log2;
}
sb->s_blocks_count = nblocks;
// nblocks is the total number of blocks in the filesystem
if (nblocks < 8)
bb_error_msg_and_die("nblocks");
// reserve blocks for superuser
sb->s_r_blocks_count = ((uint64_t) nblocks * nreserved) / 100;