doc/bugs/use_reflink_to_export_to_directory_special_remote.mdwn

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+I'm using version `10.20230321-gb624394c7` on Arch Linux and BTRFS.
+I'd love to have the directory special remote using `cp --reflink=auto` to export to a directory on the same file system.
+
+My use case is using syncthing as a way to export (parts of my repo) to my phone.
+I'm deliberately not using `adb` as this needs my phone to be connected to the computer somehow.
+I basically want to do what's described on [syncthing special remote](/todo/syncthing_special_remote/#index2h2) under “Copying objects”.
+
+The main drawback, as also noted in the linked document, is that all files are duplicated.
+As I'm using BTRFS it would really help if the `export` were to use `cp --reflink=auto` instead of its own copying mechanism.
+I've read [here](/forum/Use_reflinks_on_BTRFS_instead_of_symlinks___63__/) that you suggested (albeit 7 years ago) using a shared clone instead.
+However, this does not work for me as syncthing does not synchronize symlinks to Android (they are ignored even if they point to something).
+(Trying with a shared repo and `adjust --unlock-present` gives merge problems when dropping files from the directory.)
+
+Nearly two years ago, you wrote [here](/todo/import_from_directory_does_not_use_cp_--reflink__63___/) that you “Implemented CoW for directory special remote, comprehensively”.
+It seems to me that this is only true for importing files which, as I checked, actually uses cow.
+
+Since I want to manage relatively many files of decent size (music, audio books, pictures, videos / movies) it would be much better if the tree export would also use reflink.
+Maybe having this as an option, for the cost of not having a nice progress bar, would be something worth considering.
+
+A test script to show that an export does indeed use cow is the following:
+
+```bash
+mkdir export import
+git init repo
+cd repo
+git annex init
+git annex initremote import type=directory directory=../import encryption=none importtree=yes
+git annex initremote export type=directory directory=../export encryption=none exporttree=yes
+git config remote.import.annex-tracking-branch main
+git config remote.export.annex-tracking-branch main
+
+for i in {1..100}; do
+    dd if=/dev/urandom bs=1M count=10 of=../import/file$i
+done
+    
+git annex sync --content
+```
+After running, a `btrfs filesystem du ...` tells me that the `repo` and `import` files point to the same file, whereas `export` does not.
+
+---
+
+In general: Thank you so much for this wonderful piece of software, I'm using it for years now and manage virtually everything with it (audio, video, pictures, important documents, papers, …).