diff options
| -rw-r--r-- | util-linux/mkfs_ext2.c | 31 | ||||
| -rwxr-xr-x | util-linux/mkfs_ext2_test.sh | 41 |
2 files changed, 37 insertions, 35 deletions
diff --git a/util-linux/mkfs_ext2.c b/util-linux/mkfs_ext2.c index 380312bca..f3359c5fa 100644 --- a/util-linux/mkfs_ext2.c +++ b/util-linux/mkfs_ext2.c @@ -179,7 +179,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) uint32_t nblocks, nblocks_full, nreserved; uint32_t ngroups; uint32_t bytes_per_inode; - uint32_t first_data_block; + uint32_t first_block; uint32_t inodes_per_group; uint32_t gdtsz, itsz; time_t timestamp; @@ -247,7 +247,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) } // number of bits in one block, i.e. 8*blocksize #define blocks_per_group (8 * blocksize) - first_data_block = (EXT2_MIN_BLOCK_SIZE == blocksize); + first_block = (EXT2_MIN_BLOCK_SIZE == blocksize); blocksize_log2 = int_log2(blocksize); // Determine number of blocks @@ -278,7 +278,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) // 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_data_block, blocks_per_group); + ngroups = div_roundup(nblocks - first_block, blocks_per_group); if (0 == ngroups) bb_error_msg_and_die("ngroups"); @@ -297,7 +297,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) uint32_t rgdtsz = 0xFFFFFFFF; // maximum block number if (nblocks < rgdtsz / 1024) rgdtsz = nblocks * 1024; - rgdtsz = div_roundup(rgdtsz - first_data_block, blocks_per_group); + rgdtsz = div_roundup(rgdtsz - first_block, blocks_per_group); rgdtsz = div_roundup(rgdtsz, blocksize / sizeof(*gd)) - gdtsz; if (rgdtsz > blocksize / sizeof(uint32_t)) rgdtsz = blocksize / sizeof(uint32_t); @@ -328,17 +328,20 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) // 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; + remainder = (nblocks - first_block) % blocks_per_group; if ((1 == ngroups) && remainder && (remainder < overhead)) bb_error_msg_and_die("way small device"); - if (remainder && (remainder < overhead + 50/* e2fsprogs hardcoded */)) { + // Standard mke2fs uses 50. Looks like a bug in our calculation + // of "remainder" or "overhead" - we dont match standard mke2fs + // when we transition from one group to two groups (a bit after 8M + // image size) and for two->three groups transition (at 16M) too. + if (remainder && (remainder < overhead + 50)) { //bb_info_msg("CHOP[%u]", remainder); nblocks -= remainder; goto retry; } } - // print info if (nblocks_full - nblocks) printf("warning: %u blocks unused\n\n", nblocks_full - nblocks); printf( @@ -358,7 +361,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) , blocksize, blocksize_log2 - EXT2_MIN_BLOCK_LOG_SIZE , inodes_per_group * ngroups, nblocks , nreserved, reserved_percent - , first_data_block + , first_block , gdtsz * (blocksize / sizeof(*gd)) * blocks_per_group , ngroups , blocks_per_group, blocks_per_group @@ -367,7 +370,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) { const char *fmt = "\nSuperblock backups stored on blocks:\n" "\t%u"; - pos = first_data_block; + pos = first_block; for (i = 1; i < ngroups; i++) { pos += blocks_per_group; if (has_super(i)) { @@ -399,8 +402,8 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) 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 available for data is 1, otherwise 0 - STORE_LE(sb->s_first_data_block, first_data_block); // 0 or 1 + // 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); @@ -450,7 +453,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) gd = xzalloc(gdtsz * blocksize); buf = xmalloc(blocksize); sb->s_free_blocks_count = 0; - for (i = 0, pos = first_data_block, n = nblocks - first_data_block; + for (i = 0, pos = first_block, n = nblocks - first_block; i < ngroups; i++, pos += blocks_per_group, n -= blocks_per_group ) { @@ -498,11 +501,11 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) // dump filesystem skeleton structures // printf("Writing superblocks and filesystem accounting information: "); - for (i = 0, pos = first_data_block; i < ngroups; i++, pos += blocks_per_group) { + 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 && 0 == first_data_block) ? 1024 : 0), sb, 1024);//blocksize); + PUT(((uint64_t)pos * blocksize) + ((0 == i && 0 == first_block) ? 1024 : 0), sb, 1024);//blocksize); PUT(((uint64_t)pos * blocksize) + blocksize, gd, gdtsz * blocksize); } } diff --git a/util-linux/mkfs_ext2_test.sh b/util-linux/mkfs_ext2_test.sh index 4bc5f1ea9..a636de561 100755 --- a/util-linux/mkfs_ext2_test.sh +++ b/util-linux/mkfs_ext2_test.sh @@ -45,31 +45,30 @@ test_mke2fs() { # -:bbox +:standard -# kilobytes=60 is the minimal allowed size. -# -# kilobytes=8378 is the first value where we differ from std: -# +warning: 185 blocks unused -# Filesystem label= -# OS type: Linux -# Block size=1024 (log=0) -# Fragment size=1024 (log=0) -# -2096 inodes, 8378 blocks -# +2096 inodes, 8193 blocks -# 418 blocks reserved for the super user -# First data block=1 -# -2 block groups -# +1 block groups -# 8192 blocks per group, 8192 fragments per group -# -1048 inodes per group -# -Superblock backups stored on blocks: -# -8193 -# +2096 inodes per group -# +# kilobytes=60 is the minimal allowed size kilobytes=60 while true; do test_mke2fs || exit 1 : $((kilobytes++)) - test $kilobytes = 300000 && break + test $kilobytes = 200 && break +done + +# Transition from one block group to two +# fails in [8378..8410] range +kilobytes=$((8*1024 - 20)) +while true; do + test_mke2fs #|| exit 1 + : $((kilobytes++)) + test $kilobytes = $((8*1024 + 300)) && break +done + +# Transition from two block groups to three +# works +kilobytes=$((16*1024 - 40)) +while true; do + test_mke2fs || exit 1 + : $((kilobytes++)) + test $kilobytes = $((16*1024 + 500)) && break done exit |