mkfs.erofs is a user-space tool to create erofs filesystem images.
erofs是华为为了增强安卓性能提出的自研文件系统，其内核文档提到用户态工具:
The following git tree provides the file system user-space tools under development (ex, formatting tool mkfs.erofs): >> git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs-utils.git
tj@qemu:~/erofs-utils$ git branch -a remotes/origin/experimental remotes/origin/experimental-dip remotes/origin/mkfs-dev
切到mkfs-dev，其他2个还有问题：
tj@qemu:~/erofs-utils$ git checkout -b mkfs-dev origin/mkfs-dev Branch mkfs-dev set up to track remote branch mkfs-dev from origin. Switched to a new branch 'mkfs-dev'
ok, ls能看到东西了，看下编译介绍：
Note that mkfs.erofs can only be linked statically with lz4 library due to the dependency of experimental lz4hc apis which were added in lz4 1.8.0. Anyway, it’s a good start to begin with building the latest lz4 library statically first. :)
Dependencies lz4-1.8.0 or above
How to build with lz4 static library ./configure –with-lz4= \eg. if lz4 lib has been installed into fold of /usr/local/lib ./configure –with-lz4=/usr/local/lib && make On Fedora, static lz4 can be installed using: yum install lz4-static.x86_64 To build you should run this first: $ ./autogen.sh $ ./configure $ make
build lz4
环境:Ubuntu14.04，下一份lz4 code，要1z4-1.8.0 or above，我down了个1.8.2。
交叉工具用了aarch64-linux-android-4.9，安卓版本里也有，如果编译lz4 for x86会提示不兼容错误：
840 /home/tj/crosstools/aarch64-linux-android-4.9/bin/../lib/gcc/aarch64-linux-android/4.9.x-google/../../../../aarch64-linux-android/bin/ld: skipping incompatible /usr/local/lib/liblz4.so when searching for -llz4 841 /home/tj/crosstools/aarch64-linux-android-4.9/bin/../lib/gcc/aarch64-linux-android/4.9.x-google/../../../../aarch64-linux-android/bin/ld: skipping incompatible /usr/local/lib/liblz4.a when searching for -llz4 843 collect2: error: ld returned 1 exit status
System types: --build=BUILD configure for building on BUILD [guessed] --host=HOST cross-compile to build programs to run on HOST [BUILD]
ok, run below:
./configure --host aarch64-linux-android
会报错：
checking lz4.h presence... yes configure: WARNING: lz4.h: present but cannot be compiled configure: WARNING: lz4.h: check for missing prerequisite headers? configure: WARNING: lz4.h: see the Autoconf documentation configure: WARNING: lz4.h: section "Present But Cannot Be Compiled" configure: WARNING: lz4.h: proceeding with the compiler's result configure: WARNING: ## --------------------------------------- ## configure: WARNING: ## Report this to bluce.liguifu@huawei.com ## configure: WARNING: ## --------------------------------------- ## checking for lz4.h... no checking for LZ4_versionNumber in -llz4... no configure: error: Cannot build without lz4
找不到lz4.h? 试着按如下文档配置：
\eg. if lz4 lib has been installed into fold of /usr/local/lib ./configure –with-lz4=/usr/local/lib && make
checking lz4.h usability... yes checking lz4.h presence... yes checking for lz4.h... yes checking for LZ4_versionNumber in -llz4... yes checking that generated files are newer than configure... done configure: creating ./config.status config.status: creating Makefile config.status: creating mkfs/Makefile config.status: creating config.h config.status: executing depfiles commands config.status: executing libtool commands
前面提到的sysroot如果不加，还会出现如下错误：
configure:3411: checking whether the C compiler works 82 configure:3433: aarch64-linux-android-gcc conftest.c >&5 83 /home/tj/crosstools/aarch64-linux-android-4.9/bin/../lib/gcc/aarch64-linux-android/4.9.x-google/../../../../aarch64-linux-android/bin/ld: cannot find crtbegin_dynamic.o: No such file or directory 84 /home/tj/crosstools/aarch64-linux-android-4.9/bin/../lib/gcc/aarch64-linux-android/4.9.x-google/../../../../aarch64-linux-android/bin/ld: cannot find -lc 85 /home/tj/crosstools/aarch64-linux-android-4.9/bin/../lib/gcc/aarch64-linux-android/4.9.x-google/../../../../aarch64-linux-android/bin/ld: cannot find -ldl 86 /home/tj/crosstools/aarch64-linux-android-4.9/bin/../lib/gcc/aarch64-linux-android/4.9.x-google/../../../../aarch64-linux-android/bin/ld: cannot find crtend_android.o: No such file or directory 87 collect2: error: ld returned 1 exit status
build mkfs.erofs
有个错误：
mkfs_file.c: In function'erofs_compress_file': mkfs_file.c:600:2: error: implicit declaration of function'rpl_malloc' [-Werror=implicit-function-declaration] inode->i_inline_data = malloc(EROFS_BLKSIZE); ^ mkfs_file.c:600:23: error: assignment makes pointer from integer without a cast [-Werror] inode->i_inline_data = malloc(EROFS_BLKSIZE); ^ mkfs_file.c: In function'erofs_init_compress_context': mkfs_file.c:874:17: error: assignment makes pointer from integer without a cast [-Werror] ctx->cc_srcbuf = malloc(erofs_cfg.c_compr_maxsz); ^ mkfs_file.c:875:17: error: assignment makes pointer from integer without a cast [-Werror] ctx->cc_dstbuf = malloc(erofs_cfg.c_compr_maxsz * 2); ^ cc1: all warnings being treated as errors make[2]: *** [mkfs_erofs-mkfs_file.o] Error 1