update doc formatting
This commit is contained in:
parent
12d13c5c98
commit
ccdea382b6
|
@ -5,30 +5,31 @@
|
|||
// It will also reasonably process those files.
|
||||
//
|
||||
// == Non-directory will be copied only once ==
|
||||
//
|
||||
// A non-directory will be copied only once, only from within it's past
|
||||
// occurrence. I.e. if file /a/b was found in layers 0 and 2, only the file
|
||||
// from layer 2 will be used.
|
||||
// Directories will always be copied, even if there are duplicates. This is
|
||||
// to avoid a situation like this:
|
||||
// layer0:
|
||||
// - ./dir/
|
||||
// - ./dir/file
|
||||
// ./dir/
|
||||
// ./dir/file
|
||||
// layer1:
|
||||
// - ./dir/
|
||||
// - ./dir/file
|
||||
// ./dir/
|
||||
// ./dir/file
|
||||
// In theory, the directory from layer 1 takes precedence, so a tarball like
|
||||
// this could be created:
|
||||
// - ./dir/ (from layer1)
|
||||
// - ./dir/file1 (from layer1)
|
||||
// ./dir/ (from layer1)
|
||||
// ./dir/file1 (from layer1)
|
||||
// However, imagine the following:
|
||||
// layer0:
|
||||
// - ./dir/
|
||||
// - ./dir/file1
|
||||
// ./dir/
|
||||
// ./dir/file1
|
||||
// layer1:
|
||||
// - ./dir/
|
||||
// ./dir/
|
||||
// Then the resulting tarball would have:
|
||||
// - ./dir/file1 (from layer1)
|
||||
// - ./dir/ (from layer0)
|
||||
// ./dir/file1 (from layer1)
|
||||
// ./dir/ (from layer0)
|
||||
// Which would mean `untar` would try to untar a file to a directory which
|
||||
// was not yet created. Therefore directories will be copied to the resulting
|
||||
// tar in the order they appear in the layers.
|
||||
|
@ -44,21 +45,22 @@
|
|||
//
|
||||
// From mount.aufs(8)[1]:
|
||||
//
|
||||
// The whiteout is for hiding files on lower branches. Also it is applied to
|
||||
// stop readdir going lower branches. The latter case is called ‘opaque
|
||||
// directory.’ Any whiteout is an empty file, it means whiteout is just an
|
||||
// mark. In the case of hiding lower files, the name of whiteout is
|
||||
// ‘.wh.<filename>.’ And in the case of stopping readdir, the name is
|
||||
// ‘.wh..wh..opq’. All whiteouts are hardlinked, including ‘<writable branch
|
||||
// top dir>/.wh..wh.aufs`.
|
||||
// The whiteout is for hiding files on lower branches. Also it is applied to
|
||||
// stop readdir going lower branches. The latter case is called ‘opaque
|
||||
// directory.’ Any whiteout is an empty file, it means whiteout is just an
|
||||
// mark. In the case of hiding lower files, the name of whiteout is
|
||||
// ‘.wh.<filename>.’ And in the case of stopping readdir, the name is
|
||||
// ‘.wh..wh..opq’. All whiteouts are hardlinked, including ‘<writable branch
|
||||
// top dir>/.wh..wh.aufs`.
|
||||
//
|
||||
// My interpretation:
|
||||
// - a file/hardlink called `.wh..wh..opq` means that directory contents from
|
||||
//
|
||||
// 1. a file/hardlink called `.wh..wh..opq` means that directory contents from
|
||||
// the layers below the mentioned file should be ignored. Higher layers may add
|
||||
// files on top.
|
||||
// * Ambiguity: should the directory from the lower layers be removed? I am
|
||||
// assuming yes, but this assumptions is baseless.
|
||||
// - if file/hardlink `.wh.([^/]+)` is found, $1 should be deleted from the
|
||||
// files on top. Ambiguity: should the directory from the lower layers be
|
||||
// removed? I am assuming yes, but this assumptions is baseless.
|
||||
//
|
||||
// 2. if file/hardlink `.wh.([^/]+)` is found, $1 should be deleted from the
|
||||
// current and lower layers.
|
||||
//
|
||||
// Note: these may be regular files in practice. So this implementation will
|
||||
|
@ -71,5 +73,6 @@
|
|||
// problems reading it[2].
|
||||
//
|
||||
// [1]: https://manpages.debian.org/unstable/aufs-tools/mount.aufs.8.en.html
|
||||
//
|
||||
// [2]: https://mgorny.pl/articles/portability-of-tar-features.html
|
||||
package rootfs
|
||||
|
|
Loading…
Reference in New Issue