diff options
| -rw-r--r-- | util-linux/mkfs_ext2.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/util-linux/mkfs_ext2.c b/util-linux/mkfs_ext2.c index be9e36332..de4c8b6c6 100644 --- a/util-linux/mkfs_ext2.c +++ b/util-linux/mkfs_ext2.c @@ -309,20 +309,23 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) { // N.B. e2fsprogs does as follows! - // ninodes is the total number of inodes (files) in the file system - uint32_t ninodes = ((uint64_t) nblocks_full * blocksize) / bytes_per_inode; 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 have no more than 8*blocksize inodes + // 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 +//incompatibility on images >= 0.5GB: +//difference in sizeof(*inode) sometimes +//results in slightly bigger inodes_per_group here +//compared to standard mke2fs: 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; @@ -345,6 +348,7 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) ////) { //// 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 @@ -414,6 +418,9 @@ int mkfs_ext2_main(int argc UNUSED_PARAM, char **argv) sb = xzalloc(1024); STORE_LE(sb->s_rev_level, 1); // revision 1 filesystem STORE_LE(sb->s_magic, EXT2_SUPER_MAGIC); +//incompatibility: +//on images > 0.5GB, standard mke2fs uses 256 byte inodes. +//we always use 128 byte ones: STORE_LE(sb->s_inode_size, sizeof(*inode)); 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); |