From 4bc4da331aae13be8a39e768524a854597addd8a Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Tue, 29 May 2012 22:59:12 -0400 Subject: Reserve some disk space for the garbage collector We can't open a SQLite database if the disk is full. Since this prevents the garbage collector from running when it's most needed, we reserve some dummy space that we can free just before doing a garbage collection. This actually revives some old code from the Berkeley DB days. Fixes #27. --- src/libstore/local-store.cc | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) (limited to 'src/libstore/local-store.cc') diff --git a/src/libstore/local-store.cc b/src/libstore/local-store.cc index f04436b7f659..1ce62aeafcef 100644 --- a/src/libstore/local-store.cc +++ b/src/libstore/local-store.cc @@ -195,7 +195,7 @@ void checkStoreNotSymlink() } -LocalStore::LocalStore() +LocalStore::LocalStore(bool reserveSpace) { substitutablePathsLoaded = false; @@ -221,6 +221,24 @@ LocalStore::LocalStore() checkStoreNotSymlink(); + /* We can't open a SQLite database if the disk is full. Since + this prevents the garbage collector from running when it's most + needed, we reserve some dummy space that we can free just + before doing a garbage collection. */ + try { + Path reservedPath = nixDBPath + "/reserved"; + if (reserveSpace) { + int reservedSize = queryIntSetting("gc-reserved-space", 1024 * 1024); + struct stat st; + if (stat(reservedPath.c_str(), &st) == -1 || + st.st_size != reservedSize) + writeFile(reservedPath, string(reservedSize, 'X')); + } + else + deletePath(reservedPath); + } catch (SysError & e) { /* don't care about errors */ + } + /* Acquire the big fat lock in shared mode to make sure that no schema upgrade is in progress. */ try { -- cgit 1.4.1