gocryptfs/internal/fusefrontend/file_lock.go, branch LockSharedStorage_rebase2Mirror of gocryptfs source code on Githubhttp://nuetzlich.net/cgit/gocryptfs/atom?h=LockSharedStorage_rebase22026-07-16T19:00:08+00:00fusefrontend: LockSharedStorage: loop on EINTR, add debug output2026-07-16T19:00:08+00:00Jakob Unterwurzacher2026-07-16T18:47:57+00:00urn:sha1:c3f386d511094362ad5bb28c3a5c6c4f52a77236fusefrontend: sharedstorage: introduce UnlockSharedStorage helper2026-07-16T18:34:45+00:00Jakob Unterwurzacher2026-07-16T18:32:51+00:00urn:sha1:a244f1ae9e5a67c1bc2fedb80e82bb646993d936fusefrontend: sharedstorage: lock truncate agains concurrent access2026-07-16T18:10:19+00:00Jakob Unterwurzacher2024-12-30T11:08:41+00:00urn:sha1:0acbbc0913a3a7069984c8e52f64e302d7f52df4
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
fusefrontend: sharedstorage: use byte-range lock on file header creation2026-07-16T17:56:48+00:00Jakob Unterwurzacher2023-06-02T12:24:44+00:00urn:sha1:e56c2e44cc4dd1484cae78956f8ff72a9eea42f2
Multiple host writing to the same empty file at the same time
could have overwritten each other's newly created file header,
leading to data corruption.
Fix the race by placing a byte-range lock on the file when
creating the file header.