遇到问题
在提交友善之臂提供的内核源码到 github 上的仓库时，遇到问题，无法正常将本地的版本库同步上传到 github 上。详细的报错信息如下：
user@vmware:~/tiny4412/FriendlyARM.source.code$ git push origin
Counting objects: 6, done.
Compressing objects: 100% (6/6), done.
Writing objects: 100% (6/6), 112.48 MiB | 2.08 MiB/s, done.
Total 6 (delta 1), reused 0 (delta 0)
remote: Resolving deltas: 100% (1/1), done.
remote: error: GH001: Large files detected. You may want to try Git Large File Storage - https://git-lfs.github.com.
remote: error: Trace: 44eb3c8ef0f61d8703f7ccea30ee046b
remote: error: See http://git.io/iEPt8g for more information.
remote: error: File linux-3.5-20150929.tgz is 101.86 MB; this exceeds GitHub's file size limit of 100.00 MB
To git@github.com:tiny4412/FriendlyARM.source.code.git
! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'git@github.com:tiny4412/FriendlyARM.source.code.git'
报错中提示说 File linux-3.5-20150929.tgz is 101.86 MB; this exceeds GitHub's file size limit of 100.00 MB，另外自己百度了下，了解到大于 100M 的文件需要用 git lfs 进行管理才能提交到 github。
这里引用博客Ubuntu 14.04 LTS安装Git LFS中的一段话说明下什么是 git lfs：
Git LFS 是 git 支持大文件的一个工具。例如，大于 100M 的文件，多了之后用 Git 管理，经常会卡死。从 Git 1.8 之后的版本开始支持。有了 Git LFS，可以大幅度提升对大文件的支持性能。
安装 git lfs
访问官网 https://git-lfs.github.com 下载 gz 包，解压执行安装脚本即可。
user@vmware:~/tiny4412/git-lfs$ ls
git-lfs-linux-386-v2.5.2.tar.gz
user@vmware:~/tiny4412/git-lfs$ tar -zxvf git-lfs-linux-386-v2.5.2.tar.gz
README.md
CHANGELOG.md
git-lfs
install.sh
user@vmware:~/tiny4412/git-lfs$ ls
CHANGELOG.md git-lfs git-lfs-linux-386-v2.5.2.tar.gz install.sh README.md
user@vmware:~/tiny4412/git-lfs$ sudo ./install.sh
Git LFS initialized.
user@vmware:~/tiny4412/git-lfs$ git lfs version
git-lfs/2.5.2 (GitHub; linux 386; go 1.10.3; git 8e3c5c93)
尝试解决
因为安装 Git LFS 需要 Git 的版本不低于 1.8.5，所以安装之前，需要先查看自己的 git 版本。
user@vmware:~/tiny4412/FriendlyARM.source.code$ git --version
git version 2.7.4
没问题，我的 git 版本是在 1.8 版本之后，查看下帮助信息，看看 git lfs 怎么用
user@vmware:~/tiny4412/FriendlyARM.source.code$ git lfs help
git lfs <command> [<args>]
Git LFS is a system for managing and versioning large files in
association with a Git repository. Instead of storing the large files
within the Git repository as blobs, Git LFS stores special "pointer
files" in the repository, while storing the actual file contents on a
Git LFS server. The contents of the large file are downloaded
automatically when needed, for example when a Git branch containing
the large file is checked out.
Git LFS works by using a "smudge" filter to look up the large file
contents based on the pointer file, and a "clean" filter to create a
new version of the pointer file when the large file's contents change.
It also uses a pre-push hook to upload the large file contents to
the Git LFS server whenever a commit containing a new large file
version is about to be pushed to the corresponding Git server.
Commands
--------
Like Git, Git LFS commands are separated into high level ("porcelain")
commands and low level ("plumbing") commands.
High level commands
--------------------
* git lfs env:
Display the Git LFS environment.
* git lfs checkout:
Populate working copy with real content from Git LFS files.
* git lfs clone:
Efficiently clone a Git LFS-enabled repository.
* git lfs fetch:
Download Git LFS files from a remote.
* git lfs fsck:
Check Git LFS files for consistency.
* git lfs install:
Install Git LFS configuration.
* git lfs lock:
Set a file as "locked" on the Git LFS server.
* git lfs locks:
List currently "locked" files from the Git LFS server.
* git lfs logs:
Show errors from the Git LFS command.
* git lfs ls-files:
Show information about Git LFS files in the index and working tree.
* git lfs migrate:
Migrate history to or from Git LFS
* git lfs prune:
Delete old Git LFS files from local storage
* git lfs pull:
Fetch Git LFS changes from the remote & checkout any required working tree
files.
* git lfs push:
Push queued large files to the Git LFS endpoint.
* git lfs status:
Show the status of Git LFS files in the working tree.
* git lfs track:
View or add Git LFS paths to Git attributes.
* git lfs uninstall:
Uninstall Git LFS by removing hooks and smudge/clean filter configuration.
* git lfs unlock:
Remove "locked" setting for a file on the Git LFS server.
* git lfs untrack:
Remove Git LFS paths from Git Attributes.
* git lfs update:
Update Git hooks for the current Git repository.
* git lfs version:
Report the version number.
Low level commands
-------------------
* git lfs clean:
Git clean filter that converts large files to pointers.
* git lfs pointer:
Build and compare pointers.
* git lfs pre-push:
Git pre-push hook implementation.
* git lfs filter-process:
Git process filter that converts between large files and pointers.
* git lfs smudge:
Git smudge filter that converts pointer in blobs to the actual content.
Examples
--------
To get started with Git LFS, the following commands can be used.
1. Setup Git LFS on your system. You only have to do this once per
repository per machine:
git lfs install
2. Choose the type of files you want to track, for examples all ISO
images, with git lfs track:
git lfs track "*.iso"
3. The above stores this information in gitattributes(5) files, so
that file need to be added to the repository:
git add .gitattributes
3. Commit, push and work with the files normally:
git add file.iso
git commit -m "Add disk image"
git push
帮助的最后给出了使用 git lfs 的示例，那么我们就参考这个示例来提交 linux-3.5 源码文件吧
user@vmware:~/tiny4412/FriendlyARM.source.code$ git lfs track linux-3.5-20150929.tgz
Tracking "linux-3.5-20150929.tgz"
user@vmware:~/tiny4412/FriendlyARM.source.code$ git add .gitattributes
user@vmware:~/tiny4412/FriendlyARM.source.code$ git push origin
Counting objects: 6, done.
Compressing objects: 100% (6/6), done.
Writing objects: 100% (6/6), 112.48 MiB | 2.25 MiB/s, done.
Total 6 (delta 1), reused 0 (delta 0)
remote: Resolving deltas: 100% (1/1), done.
remote: error: GH001: Large files detected. You may want to try Git Large File Storage - https://git-lfs.github.com.
remote: error: Trace: 3e6e6cee79d8ac960dc2c335eaf5326b
remote: error: See http://git.io/iEPt8g for more information.
remote: error: File linux-3.5-20150929.tgz is 101.86 MB; this exceeds GitHub's file size limit of 100.00 MB
To git@github.com:tiny4412/FriendlyARM.source.code.git
! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to 'git@github.com:tiny4412/FriendlyARM.source.code.git'
还是没有成功，怎么回事，使用 git lfs 也不行，难道这个 100M 的限制不是 git 工具的限制，而是 github 的限制？还是说我之前已经将 linux-3.5 源码先提交了，导致二次 track 不生效？
目前的提交记录为：
commit e201f89c2c576c8f1e126ce582ef3b5c30711264
Author: mz8023yt <mz8023yt@163.com>
Date: Thu Oct 4 15:27:51 2018 +0800
code: add rootfs
commit 6e1d6f365264da2b933786b59e9def02e5351b6f
Author: mz8023yt <mz8023yt@163.com>
Date: Mon Sep 24 21:51:35 2018 +0800
code: add kernel
commit 9b30299a4a969d9b1aab01ba32bb85c1735a5f32
Author: mz8023yt <mz8023yt@163.com>
Date: Sun Sep 23 23:46:35 2018 +0800
code: add uboot
回退到 9b30299a4a969d9b1aab01ba32bb85c1735a5f32 节点再试一次看看
user@vmware:~/tiny4412/FriendlyARM.source.code$ mv rootfs-huangweizhong.tar.gz ../
user@vmware:~/tiny4412/FriendlyARM.source.code$ mv linux-3.5-20150929.tgz ../
user@vmware:~/tiny4412/FriendlyARM.source.code$ git reset --hard 9b30299a4a969d9b1aab01ba32bb85c1735a5f32
user@vmware:~/tiny4412/FriendlyARM.source.code$ git log
commit 9b30299a4a969d9b1aab01ba32bb85c1735a5f32
Author: mz8023yt <mz8023yt@163.com>
Date: Sun Sep 23 23:46:35 2018 +0800
code: add uboot
回退了两笔，先把 rootfs 那笔先提交掉
user@vmware:~/tiny4412/FriendlyARM.source.code$ mv ../rootfs-huangweizhong.tar.gz ./
user@vmware:~/tiny4412/FriendlyARM.source.code$ git st
On branch master
Your branch is up-to-date with 'origin/master'.
Untracked files:
(use "git add <file>..." to include in what will be committed)
rootfs-huangweizhong.tar.gz
user@vmware:~/tiny4412/FriendlyARM.source.code$ git add --all
user@vmware:~/tiny4412/FriendlyARM.source.code$ git commit -m "code: add the rootfs"
[master 87fafa1] code: add the rootfs
1 file changed, 0 insertions(+), 0 deletions(-)
create mode 100755 rootfs-huangweizhong.tar.gz
user@vmware:~/tiny4412/FriendlyARM.source.code$ git push origin
Counting objects: 3, done.
Compressing objects: 100% (3/3), done.
Writing objects: 100% (3/3), 10.86 MiB | 1.34 MiB/s, done.
Total 3 (delta 0), reused 0 (delta 0)
To git@github.com:tiny4412/FriendlyARM.source.code.git
9b30299..87fafa1 master -> master
user@vmware:~/tiny4412/FriendlyARM.source.code$ clear
user@vmware:~/tiny4412/FriendlyARM.source.code$ git st
On branch master
Your branch is up-to-date with 'origin/master'.
nothing to commit, working directory clean
再重新试试使用 git lfs 提交 linux-3.5
user@vmware:~/tiny4412/FriendlyARM.source.code$ mv ../linux-3.5-20150929.tgz ./
user@vmware:~/tiny4412/FriendlyARM.source.code$ git lfs track linux-3.5-20150929.tgz
Tracking "linux-3.5-20150929.tgz"
user@vmware:~/tiny4412/FriendlyARM.source.code$ git add .gitattributes
user@vmware:~/tiny4412/FriendlyARM.source.code$ git add linux-3.5-20150929.tgz
user@vmware:~/tiny4412/FriendlyARM.source.code$ git commit -m "code: add the kernel"
[master 943ad9e] code: add the kernel
2 files changed, 4 insertions(+)
create mode 100644 .gitattributes
create mode 100755 linux-3.5-20150929.tgz
user@vmware:~/tiny4412/FriendlyARM.source.code$ git push origin
Counting objects: 4, done.% (1/1), 107 MB | 1.5 MB/s
Compressing objects: 100% (4/4), done.
Writing objects: 100% (4/4), 564 bytes | 0 bytes/s, done.
Total 4 (delta 0), reused 0 (delta 0)
To git@github.com:tiny4412/FriendlyARM.source.code.git
87fafa1..943ad9e master -> master
很好，成功提交到了 github 上
简单总结
通过这个问题得到的收获是：
- 大文件不要直接用 git 管理，即使没有大到 100M 以上，也要用 git lfs 来管理，提高 git 使用的性能。
- 我们仓库使用了 git lfs 管理，别人克隆是否也需要通过 git lfs clone 克隆，需要做实验验证下。
- 先提交过的文件，再通过 git lfs track 不生效，需要回退重新 track 后再 commit 才生效。
验证实验
使用 git clone 直接克隆仓库，看看是否可以成功
user@vmware:~/tiny4412$ cd demo/
user@vmware:~/tiny4412/demo$ git clone git@github.com:tiny4412/FriendlyARM.source.code.git
Cloning into 'FriendlyARM.source.code'...
remote: Enumerating objects: 10, done.
remote: Counting objects: 100% (10/10), done.
remote: Compressing objects: 100% (10/10), done.
remote: Total 10 (delta 1), reused 9 (delta 0), pack-reused 0
Receiving objects: 100% (10/10), 22.01 MiB | 2.44 MiB/s, done.
Resolving deltas: 100% (1/1), done.
Checking connectivity... done.
Downloading linux-3.5-20150929.tgz (107 MB)
user@vmware:~/tiny4412/demo$ cd FriendlyARM.source.code/
user@vmware:~/tiny4412/demo/FriendlyARM.source.code$ ls
linux-3.5-20150929.tgz rootfs-huangweizhong.tar.gz uboot_tiny4412-20130729.tgz
使用 git lfs clone 克隆看看
user@vmware:~/tiny4412$ mkdir demo.lfs
user@vmware:~/tiny4412$ cd demo.lfs/
user@vmware:~/tiny4412/demo.lfs$ git lfs clone git@github.com:tiny4412/FriendlyARM.source.code.git
Cloning into 'FriendlyARM.source.code'...
remote: Enumerating objects: 10, done.
remote: Counting objects: 100% (10/10), done.
remote: Compressing objects: 100% (10/10), done.
remote: Total 10 (delta 1), reused 9 (delta 0), pack-reused 0
Receiving objects: 100% (10/10), 22.01 MiB | 872.00 KiB/s, done.
Resolving deltas: 100% (1/1), done.
Checking connectivity... done.
user@vmware:~/tiny4412/demo.lfs$ 1), 107 MB | 1.5 MB/s
user@vmware:~/tiny4412/demo.lfs$ cd FriendlyARM.source.code/
user@vmware:~/tiny4412/demo.lfs/FriendlyARM.source.code$ ls
linux-3.5-20150929.tgz rootfs-huangweizhong.tar.gz uboot_tiny4412-20130729.tgz
看起来是两者都可以正常 clone，先记着目前的验证结论，以后有补充的话再补充。
