build shrunken .seed.btrfs images internally

2 files changed, 13 insertions, 3 deletions

diff --git a/Makefile b/Makefile
index fd6aa0b..b146673 100644
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,7 @@ sudo := $(shell [ "$(id -u)" = 0 ] || echo sudo)
 build:
         stack build
 
-executables = ~/.local/bin/$(binary) ./selfstrap
+executables = ~/.local/bin/$(binary) ./selfstrap ./btrfs-shrink
 
 install: build
         stack install
diff --git a/fsmgr.hs b/fsmgr.hs
index dca488e..2aff987 100644
--- a/fsmgr.hs
+++ b/fsmgr.hs
@@ -241,7 +241,7 @@ buildInitialImage DiskImageConfig{..} mountpoint out = do
       cmd_ "mount -t btrfs" [out] mountpoint
 
     SeededImage n f -> do
-      let parent = "_build" </> f -<.> "btrfs"
+      let parent = f -<.> "seed.btrfs"
       need [parent]
 
       devices <- either (const []) lines . readEither <$> liftIO (readFileOptional (parent <.> "devices.txt"))
@@ -464,7 +464,17 @@ shakeRules = do
     need [cfgFile]
     cfg <- readEither <$> readFile' cfgFile
     either (error . (("Error parsing file: " ++ cfgFile ++ ": ") ++)) (flip buildRoot out) cfg
-  "*.btrfs" %> \out -> do
+  priority 2 $ "*.seed.btrfs" %> \out -> do
+    let tmp = out <.> "tmp"
+        inp = dropExtension out -<.> ".btrfs"
+    need [inp]
+    cmd_ "cp --reflink=always" [inp, tmp]
+    cmd_ "btrfstune -f -S0" [tmp]
+    cmd_ "btrfs-shrink" [tmp]
+    cmd_ "btrfstune -f -S1" [tmp]
+    cmd_ (WithStderr False) "mv -i" [tmp, out]
+
+  priority 1 $ "*.btrfs" %> \out -> do
     need ["_build" </> out]
     -- WithStderr False needed for `cp` to interact with the tty
     cmd_ (WithStderr False) "cp --reflink=always -i" ["_build" </> out, out]