The tar archive format, its extensions, and why GNU tar extracts in quadratic time - Mort's Ramblings

Date: 2022-07-23 Git: https://gitlab.com/mort96/blog/blob/published/content/00000-home/00014-tar.md (If you're here from Google and just need help with tar being slow: If you trust the tar archive, extract with -P to make tar fast.) A couple of days ago, I had a 518GiB tar.gz file (1.1 TiB uncompressed) that I had to extract. At first, GNU tar was doing a great job, chewing through the tar.gz at a

[punychan]

tar内のファイル数（".." を含むシンボリックリンクが800000個、ハードリンクが5400000個、みたいな）が多いと、全ファイルに対してディレクトリトラバーサルのチェックをするので個数の2乗でだんだん遅くなるという話。