From b11aeec30866fe97b3c23488d51a47a040991b04 Mon Sep 17 00:00:00 2001 From: Jakob Unterwurzacher Date: Mon, 30 Dec 2024 12:08:41 +0100 Subject: fusefrontend: sharedstorage: lock truncate agains concurrent access Prevent reads and writes concurrent with the truncate operation. It's racy on tmpfs and ext4 ( https://lore.kernel.org/all/18e9fa0f-ec31-9107-459c-ae1694503f87@gmail.com/t/ ) as evident by TestOpenTruncate test failures: === RUN TestOpenTruncate cluster_test.go:209: POSIX compliance issue: non-exlusive create failed with err=file exists doRead 16384215: corrupt block #0: cipher: message authentication failed ino16384215 fh8: RMW read failed: errno=5 cluster_test.go:214: iteration 1: WriteAt: write /tmp/gocryptfs-test-parent-1026/1358464214/TestOpenTruncate.1788296708.mnt2/foo: input/output error --- FAIL: TestOpenTruncate (0.06s) FAIL exit status 1 FAIL github.com/rfjakob/gocryptfs/v2/tests/cluster 7.880s Relates-to: https://github.com/rfjakob/gocryptfs/issues/56 --- internal/fusefrontend/file_lock.go | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'internal/fusefrontend/file_lock.go') diff --git a/internal/fusefrontend/file_lock.go b/internal/fusefrontend/file_lock.go index 6f92cfe..bb72c52 100644 --- a/internal/fusefrontend/file_lock.go +++ b/internal/fusefrontend/file_lock.go @@ -6,7 +6,9 @@ import ( "github.com/rfjakob/gocryptfs/v2/internal/syscallcompat" ) -// SharedStorageLock conveniently wraps F_OFD_SETLKW +// SharedStorageLock conveniently wraps F_OFD_SETLKW. +// It is a no-op unless args.SharedStorage is set. +// // See https://man7.org/linux/man-pages/man2/fcntl.2.html -> "Open file description locks (non-POSIX)" // // lkType is one of: -- cgit v1.2.3