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mkfs_ext2: further work by Vladimir

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Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2009-10-20 13:34:16 +02:00
parent 69f2e2cdeb
commit 95484c8706
2 changed files with 69 additions and 45 deletions
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76
util-linux/mkfs_ext2.c
View File

@ -173,9 +173,9 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
unsigned i, pos, n;
unsigned bs, bpi;
unsigned blocksize, blocksize_log2;
unsigned nreserved = 5;
unsigned reserved_percent = 5;
unsigned long long kilobytes;
uint32_t nblocks, nblocks_full;
uint32_t nblocks, nblocks_full, nreserved;
uint32_t ngroups;
uint32_t bytes_per_inode;
uint32_t first_data_block;
@ -194,13 +194,9 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
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, &bpi, NULL, NULL, NULL, NULL,
&nreserved, NULL, NULL, &label, NULL, NULL, NULL, NULL, NULL, NULL);
&reserved_percent, NULL, NULL, &label, NULL, NULL, NULL, NULL, NULL, NULL);
argv += optind; // argv[0] -- device
// reserved blocks percentage
if (nreserved > 50)
bb_error_msg_and_die("-%c is bad", 'm');
// check the device is a block device
xmove_fd(xopen(argv[0], O_WRONLY), fd);
fstat(fd, &st);
@ -228,14 +224,15 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
if (opts & OPT_i)
bytes_per_inode = bpi;
// Determine block size
// block size is a multiple of 1024
blocksize = 1024;
if (kilobytes >= 512*1024) // mke2fs 1.41.9 compat
blocksize = 4096;
if (EXT2_MAX_BLOCK_SIZE > 4096) {
// kilobytes >> 22 == size in 4gigabyte chunks.
// if it is >= 16k gigs, blocksize must be increased.
// Try "mke2fs -F image_std $((16 * 1024*1024*1024))"
// if size >= 16k gigs, blocksize must be increased.
// Try "mke2fs -F image $((16 * 1024*1024*1024))"
while ((kilobytes >> 22) >= blocksize)
blocksize *= 2;
}
@ -247,28 +244,38 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
) {
bb_error_msg_and_die("blocksize %u is bad", blocksize);
}
// number of bits in one block, i.e. 8*blocksize
#define blocks_per_group (8 * blocksize)
first_data_block = (EXT2_MIN_BLOCK_SIZE == blocksize);
blocksize_log2 = int_log2(blocksize);
// Determine number of blocks
kilobytes >>= (blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE);
// nblocks: the total number of blocks in the filesystem
nblocks = kilobytes;
if (nblocks != kilobytes)
bb_error_msg_and_die("block count doesn't fit in 32 bits");
#define kilobytes kilobytes_unused_after_this
if (blocksize < PAGE_SIZE)
nblocks &= ~((PAGE_SIZE / blocksize)-1);
nblocks &= ~((PAGE_SIZE >> blocksize_log2)-1);
// Experimentally, standard mke2fs won't work on images smaller than 60k
if (nblocks < 60)
bb_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 = div_roundup((uint64_t) nblocks * reserved_percent, 100);
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:
if (nblocks < 8)
bb_error_msg_and_die("need >= 8 blocks");
// number of bits in one block, i.e. 8*blocksize
#define blocks_per_group (8 * blocksize)
// N.B. a block group can have no more than blocks_per_group blocks
first_data_block = (EXT2_MIN_BLOCK_SIZE == blocksize);
ngroups = div_roundup(nblocks - first_data_block, blocks_per_group);
if (0 == ngroups)
bb_error_msg_and_die("ngroups");
@ -308,21 +315,21 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
if (inodes_per_group < 16)
inodes_per_group = 16;
// N.B. a block group can have no more than 8*blocksize inodes
// a block group can have no more than 8*blocksize inodes
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 * sizeof(*inode), blocksize) << blocksize_log2) / sizeof(*inode);
inodes_per_group = (div_roundup(inodes_per_group * sizeof(*inode), blocksize) * blocksize) / sizeof(*inode);
// make sure the number of inodes per group is a multiple of 8
inodes_per_group &= ~7;
itsz = div_roundup(inodes_per_group * sizeof(*inode), blocksize);
// the last block needs more attention: doesn't it too small for possible overhead?
// the last group needs more attention: isn't it too small for possible overhead?
overhead = (has_super(ngroups - 1) ? (1/*sb*/ + gdtsz) : 0) + 1/*bbmp*/ + 1/*ibmp*/ + itsz;
remainder = (nblocks - first_data_block) % blocks_per_group;
if ((1 == ngroups) && remainder && (remainder < overhead))
bb_error_msg_and_die("way small device");
if (remainder && (remainder < overhead + 50)) {
if (remainder && (remainder < overhead + 50/* e2fsprogs hardcoded */)) {
//bb_info_msg("CHOP[%u]", remainder);
nblocks -= remainder;
goto retry;
@ -348,8 +355,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
, blocksize, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE
, blocksize, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE
, inodes_per_group * ngroups, nblocks
//, div_roundup((uint64_t) nblocks * nreserved, 100), nreserved
, (unsigned)((uint64_t) nblocks_full * nreserved / 100), nreserved
, nreserved, reserved_percent
, first_data_block
, gdtsz * (blocksize / sizeof(*gd)) * blocks_per_group
, ngroups
@ -399,7 +405,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
// blocks
STORE_LE(sb->s_blocks_count, nblocks);
// reserve blocks for superuser
STORE_LE(sb->s_r_blocks_count, (uint32_t)((uint64_t) nblocks_full * nreserved / 100));
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);
@ -418,7 +424,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
| (EXT2_FEATURE_COMPAT_RESIZE_INO * ENABLE_FEATURE_MKFS_EXT2_RESERVED_GDT)
| (EXT2_FEATURE_COMPAT_DIR_INDEX * ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX)
);
// e2fsprogs-1.41.9 doesn't like EXT2_FEATURE_INCOMPAT_WHITEOUT
// e2fsck from 1.41.9 doesn't like EXT2_FEATURE_INCOMPAT_WHITEOUT
STORE_LE(sb->s_feature_incompat, EXT2_FEATURE_INCOMPAT_FILETYPE);// | EXT2_FEATURE_INCOMPAT_WHITEOUT;
STORE_LE(sb->s_feature_ro_compat, EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER);
STORE_LE(sb->s_flags, EXT2_FLAGS_SIGNED_HASH * ENABLE_FEATURE_MKFS_EXT2_DIR_INDEX);
@ -435,8 +441,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
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, if any
if (label) //opts & OPT_L)
// write the label
safe_strncpy((char *)sb->s_volume_name, label, sizeof(sb->s_volume_name));
// fill group descriptors
@ -461,11 +466,6 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
STORE_LE(gd[i].bg_used_dirs_count, 2);
gd[i].bg_free_inodes_count -= EXT2_GOOD_OLD_FIRST_INO;
}
// // N.B. the following is pure heuristics!
// // Likely to cope with 1024-byte blocks, when first block is for boot sectors
// if (ngroups-1 == i) {
// n -= first_data_block;
// }
// mark preallocated blocks as allocated
fb = (n < blocks_per_group ? n : blocks_per_group) - overhead;
@ -500,8 +500,8 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv)
// dump superblock and group descriptors and their backups
if (has_super(i)) {
// N.B. 1024 byte blocks are special
PUT(((uint64_t)pos << blocksize_log2) + ((0 == i && 0 == first_data_block) ? 1024 : 0), sb, 1024);//blocksize);
PUT(((uint64_t)pos << blocksize_log2) + blocksize, gd, gdtsz * blocksize);
PUT(((uint64_t)pos * blocksize) + ((0 == i && 0 == first_data_block) ? 1024 : 0), sb, 1024);//blocksize);
PUT(((uint64_t)pos * blocksize) + blocksize, gd, gdtsz * blocksize);
}
}
@ -526,12 +526,12 @@ 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], FETCH_LE32(gd[0].bg_inode_table) + itsz);
PUT(((uint64_t)FETCH_LE32(gd[0].bg_inode_table) << blocksize_log2) + (EXT2_ROOT_INO-1) * sizeof(*inode), buf, sizeof(*inode));
PUT(((uint64_t)FETCH_LE32(gd[0].bg_inode_table) * blocksize) + (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
PUT(((uint64_t)FETCH_LE32(gd[0].bg_inode_table) << blocksize_log2) + (EXT2_GOOD_OLD_FIRST_INO-1) * sizeof(*inode), buf, sizeof(*inode));
PUT(((uint64_t)FETCH_LE32(gd[0].bg_inode_table) * blocksize) + (EXT2_GOOD_OLD_FIRST_INO-1) * sizeof(*inode), buf, sizeof(*inode));
// dump directories
memset(buf, 0, blocksize);

36
util-linux/mkfs_ext2_test.sh
View File

@ -23,7 +23,7 @@ run_test() { # params: mke2fs_invocation image_name
test_mke2fs() {
echo Testing $kilobytes
run_test '/usr/bin/mke2fs' image_std || return 1
run_test '/sbin/mke2fs' image_std || return 1
run_test './busybox mke2fs' image_bb || return 1
diff -ua image_bb.out image_std.out >image.out.diff || {
@ -31,9 +31,33 @@ test_mke2fs() {
return 1
}
e2fsck -f -n image_bb >/dev/null 2>&1 || { echo "e2fsck error on image_bb"; exit 1; }
e2fsck -f -n image_bb >/dev/null 2>&1 || {
echo "e2fsck error on image_bb"
e2fsck -f -n image_bb
exit 1
}
}
# Should start from kilobytes=60, but e2fsck complains on it:
# e2fsck 1.41.4 (27-Jan-2009)
# Pass 1: Checking inodes, blocks, and sizes
# Pass 2: Checking directory structure
# Pass 3: Checking directory connectivity
# Pass 4: Checking reference counts
# Pass 5: Checking group summary information
# Inode bitmap differences: +(9--11)
# Free inodes count wrong for group #0 (5, counted=8).
# Directories count wrong for group #0 (2, counted=1).
# Free inodes count wrong (5, counted=8).
# image_bb: 11/16 files (0.0% non-contiguous), 9/60 blocks
kilobytes=68
while true; do
test_mke2fs #|| exit 1
: $((kilobytes++))
done
exit
# Specific sizes with known differences:
# -:bbox +:standard
# -6240 inodes, 24908 blocks
@ -58,14 +82,14 @@ kilobytes=1218 test_mke2fs
# +2064 inodes per group
kilobytes=57696 test_mke2fs
# This size results in "warning: 75 blocks unused"
kilobytes=98380 test_mke2fs
# -warning: 239 blocks unused.
# +warning: 242 blocks unused.
kilobytes=49395 test_mke2fs
## This size results in "warning: 75 blocks unused"
#kilobytes=98380 test_mke2fs
while true; do
kilobytes=$(( (RANDOM*RANDOM) % 1000000 + 2000))
kilobytes=$(( (RANDOM*RANDOM) % 1000000 + 60))
test_mke2fs || exit 1
done