diff options
| -rw-r--r-- | toys/mke2fs.c | 186 | ||||
| -rw-r--r-- | toys/toylist.h | 2 |
2 files changed, 111 insertions, 77 deletions
diff --git a/toys/mke2fs.c b/toys/mke2fs.c index 64d65eba..931dec7f 100644 --- a/toys/mke2fs.c +++ b/toys/mke2fs.c @@ -55,7 +55,7 @@ static uint32_t count_blocks_used(uint64_t size) // assigns bytes used to *size. Writes total block count to TT.treeblocks // and inode count to TT.treeinodes. -long check_treesize(struct dirtree *this, off_t *size) +static long check_treesize(struct dirtree *this, off_t *size) { long blocks; @@ -94,11 +94,15 @@ static void check_treelinks(void) struct dirtree *this, *that; for (this = TT.dt; this; this = treenext(this)) { - this->st.st_nlink = 0; - for (that = TT.dt; that; that = treenext(that)) - if (this->st.st_ino == that->st.st_ino) - if (this->st.st_dev == that->st.st_dev) - this->st.st_nlink++; + // Since we can't hardlink to directories, we know their link count. + if (S_ISDIR(this->st.st_mode)) this->st.st_nlink = 2; + else { + this->st.st_nlink = 0; + for (that = TT.dt; that; that = treenext(that)) + if (this->st.st_ino == that->st.st_ino) + if (this->st.st_dev == that->st.st_dev) + this->st.st_nlink++; + } } } @@ -127,6 +131,16 @@ static void create_uuid(char *uuid) uuid[11] = uuid[11] | 128; } +// Figure out inodes per group, rounded up to fill complete inode blocks. +static uint32_t get_inodespg(uint32_t inodes) +{ + uint32_t temp; + + 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 static void init_superblock(struct ext2_superblock *sb) @@ -142,8 +156,7 @@ static void init_superblock(struct ext2_superblock *sb) // Fill out blocks_count, r_blocks_count, first_data_block sb->blocks_count = SWAP_LE32(TT.blocks); - if (!TT.reserved_percent) TT.reserved_percent = 5; - temp = (TT.blocks * (uint64_t)TT.reserved_percent) /100; + 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); @@ -151,31 +164,16 @@ static void init_superblock(struct ext2_superblock *sb) // 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)? - temp = TT.blocksize*8; - sb->blocks_per_group = sb->frags_per_group = SWAP_LE32(temp); + sb->blocks_per_group = sb->frags_per_group = SWAP_LE32(TT.blockbits); // How many block groups do we need? (Round up avoiding integer overflow.) - TT.groups = (TT.blocks)/temp; - if (TT.blocks & (temp-1)) TT.groups++; - - // Figure out how many total inodes we need. - - if (!TT.inodespg) { - if (!TT.bytes_per_inode) TT.bytes_per_inode = 8192; - TT.inodespg = (TT.blocks * (uint64_t)TT.blocksize) / TT.bytes_per_inode; - } + TT.groups = (TT.blocks)/TT.blockbits; + if (TT.blocks & (TT.blockbits-1)) TT.groups++; // Figure out inodes per group, rounded up to block size. - // How many blocks of inodes total, rounded up - temp = TT.inodespg / (TT.blocksize/sizeof(struct ext2_inode)); - if (temp * (TT.blocksize/sizeof(struct ext2_inode)) != TT.inodespg) temp++; - // How many blocks of inodes per group, again rounded up - TT.inodespg = temp / TT.groups; - if (temp & (TT.groups-1)) TT.inodespg++; - // How many inodes per group is that? - TT.inodespg *= (TT.blocksize/sizeof(struct ext2_inode)); + TT.inodespg = get_inodespg(TT.inodespg); // Set inodes_per_group and total inodes_count sb->inodes_per_group = SWAP_LE32(TT.inodespg); @@ -201,34 +199,53 @@ static void init_superblock(struct ext2_superblock *sb) // sb->feature_compat |= SWAP_LE32(EXT3_FEATURE_COMPAT_HAS_JOURNAL); } -// Number of blocks used in this group by superblock/group list backup. -// Returns 0 if this group doesn't have a superblock backup. -static int group_superblock_used(uint32_t group) +// Does this group contain a superblock backup (and group descriptor table)? +static int is_sb_group(uint32_t group) { - int used = 0, i; + int i; // Superblock backups are on groups 0, 1, and powers of 3, 5, and 7. - if(!group || group==1) used++; + if(!group || group==1) return 1; for (i=3; i<9; i+=2) { int j = i; while (j<group) j*=i; - if (j==group) used++; + if (j==group) return 1; } + return 0; +} - if (used) { - // How blocks does the group 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++; - } + +// Number of blocks used in this group by superblock/group list backup. +static int group_superblock_used(uint32_t group) +{ + int used; + + if (!is_sb_group(group)) return 0; + + // How blocks does the group 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; } +static uint32_t get_all_group_blocks(void) +{ + uint32_t i, blocks, inodeblks; + + inodeblks = get_inodespg(TT.inodespg); + inodeblks /= TT.blocksize/sizeof(struct ext2_inode); + for (i = blocks = 0; i<TT.groups; i++) + blocks += group_superblock_used(i) + 2 + inodeblks; + + return blocks; +} + static void bits_set(char *array, int start, int len) { while(len) { @@ -283,7 +300,7 @@ static void fill_inode(struct ext2_inode *in, struct dirtree *this) int mke2fs_main(void) { - int i, temp, blockbits; + int i, temp; off_t length; // Handle command line arguments. @@ -292,6 +309,27 @@ int mke2fs_main(void) 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; + + // Figure out how many total inodes we need. + + if (!TT.inodespg) { + if (!TT.bytes_per_inode) TT.bytes_per_inode = 8192; + TT.inodespg = (TT.blocks * (uint64_t)TT.blocksize) / TT.bytes_per_inode; + } // Collect gene2fs list or lost+found, calculate requirements. @@ -305,50 +343,46 @@ int mke2fs_main(void) TT.dt->st.st_ctime = TT.dt->st.st_mtime = time(NULL); } - // 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. - - length = fdlength(TT.fsfd); - if (!TT.blocksize) TT.blocksize = (length && length < 1<<29) ? 1024 : 4096; - if (!TT.blocks) TT.blocks = length/TT.blocksize; - if (!TT.blocks) error_exit("gene2fs is a TODO item"); + // Figure out how much space is used by preset files + length = 0; + length = check_treesize(TT.dt, &length); + check_treelinks(); // Calculate st_nlink for each node in tree. + + if (TT.gendir && !TT.blocks) { + // Figure out how many blocks of overhead superblock backups and + // group descriptor tables impose. Start with a minimal guess, + // find the overhead for that many groups, and loop until this + // is enough groups to store this many blocks. + TT.groups = (TT.treeblocks/TT.blockbits)+1; + for (;;) { + TT.blocks = TT.treeblocks + get_all_group_blocks(); + if (TT.blocks <= TT.groups * TT.blockbits) break; + TT.groups++; + } + } - // Skip the first 1k to avoid the boot sector (if any), then - // initialize superblock structure + // TT.blocks is now big enough to initialize superblock structure - put_zeroes(1024); init_superblock(&TT.sb); - blockbits = 8*TT.blocksize; + temp = get_all_group_blocks(); + if (TT.blocks < TT.treeblocks + temp) error_exit("Not enough space.\n"); - // Figure out how much space is used - length = 0; - length = check_treesize(TT.dt, &length); - for (temp=i=0; i<TT.groups; i++) { - temp += group_superblock_used(i) + 2; - temp += TT.inodespg/(TT.blocksize/sizeof(struct ext2_inode)); - } TT.sb.free_blocks_count = SWAP_LE32(TT.blocks - TT.treeblocks - temp); TT.sb.free_inodes_count = SWAP_LE32(TT.inodespg*TT.groups - INODES_RESERVED - TT.treeinodes); - // Calculate st_nlink for each node in tree. - - check_treelinks(); - - // Loop through block groups. + // Skip the first 1k to avoid the boot sector (if any) + put_zeroes(1024); + // Loop through block groups, write out each one. 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 = blockbits; - if ((i+1)*blockbits > TT.blocks) end = TT.blocks & (blockbits-1); + 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; @@ -391,7 +425,7 @@ int mke2fs_main(void) bg[slot].free_blocks_count = SWAP_LE32(temp); // Fill out rest of group structure (TODO: gene2fs allocation) - used += j*blockbits; + 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); @@ -406,13 +440,13 @@ int mke2fs_main(void) memset(toybuf, 0, TT.blocksize); bits_set(toybuf, 0, start+itable); - if (end!=blockbits) bits_set(toybuf, end, blockbits-end); + if (end!=TT.blockbits) bits_set(toybuf, end, TT.blockbits-end); xwrite(TT.fsfd, toybuf, TT.blocksize); // Write inode bitmap (TODO) memset(toybuf, 0, TT.blocksize); if (!i) bits_set(toybuf, 0, INODES_RESERVED); - bits_set(toybuf, TT.inodespg, blockbits-TT.inodespg); + bits_set(toybuf, TT.inodespg, TT.blockbits-TT.inodespg); xwrite(TT.fsfd, toybuf, TT.blocksize); start += 3; diff --git a/toys/toylist.h b/toys/toylist.h index c2fff141..173e870a 100644 --- a/toys/toylist.h +++ b/toys/toylist.h @@ -25,7 +25,7 @@ struct mke2fs_data { long reserved_percent; char *gendir; - unsigned blocks, groups, treeblocks, treeinodes; + unsigned blocks, groups, blockbits, treeblocks, treeinodes; int fsfd, noseek; struct ext2_superblock sb; struct dirtree *dt; |