From 2e9d6565fcc10268b7db6d44d74f9b48d2c2354c Mon Sep 17 00:00:00 2001 From: Maxim Cournoyer Date: Thu, 4 Jun 2020 16:14:26 -0400 Subject: [PATCH] packages/pkg-download.mk: fix file locking over NFS BSD style locks such as implemented by flock are translated to POSIX advisory file locks (implemented by the fcntl system call on Linux). It is not possible to lock a directory using POSIX advisory file locks. Hence, the lock strategy used by Buildroot doesn't work when used over NFS. Using flock on a simple file works correctly though, so use a '.lock' file inside the download directory instead. If the lockfile does not exist, flock will create it (in a race-free fashion). Tested using NFS v4.2 and Linux 5.4.43. Signed-off-by: Maxim Cournoyer [yann.morin.1998@free.fr: - slightly expand commit log about creation of the lockfile ] Signed-off-by: Yann E. MORIN --- package/pkg-download.mk | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/package/pkg-download.mk b/package/pkg-download.mk index de619ba90a..951d2fb554 100644 --- a/package/pkg-download.mk +++ b/package/pkg-download.mk @@ -99,7 +99,7 @@ endif define DOWNLOAD $(Q)mkdir -p $($(2)_DL_DIR) - $(Q)$(EXTRA_ENV) flock $($(2)_DL_DIR)/ $(DL_WRAPPER) \ + $(Q)$(EXTRA_ENV) flock $($(2)_DL_DIR)/.lock $(DL_WRAPPER) \ -c '$($(2)_DL_VERSION)' \ -d '$($(2)_DL_DIR)' \ -D '$(DL_DIR)' \