[PATCH] D92686: [Support] Add workaround for a bug in fuse-overlayfs

[Tom Stellard via Phabricator via llvm-commits]

tstellar created this revision.
Herald added subscribers: dexonsmith, sunfish, hiraditya.
tstellar requested review of this revision.
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This fixes the following lit tests when running in a podman container
using fuse-overlayfs:

lld :: COFF/lto-cache.ll
lld :: ELF/lto/cache.ll
lld :: wasm/lto/cache.ll

Fixes: PR48380


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D92686

Files:
  llvm/lib/Support/Unix/Path.inc


Index: llvm/lib/Support/Unix/Path.inc
===================================================================
--- llvm/lib/Support/Unix/Path.inc
+++ llvm/lib/Support/Unix/Path.inc
@@ -315,7 +315,19 @@
 }
 
 TimePoint<> basic_file_status::getLastAccessedTime() const {
-  return toTimePoint(fs_st_atime, fs_st_atime_nsec);
+  // There is a bug in fuse-overlayfs, which is a filesystem mostly used by
+  // containers, which causes the value of atime to be incorrect in some
+  // specific scenarios.  The value of mtime is not affected, so we can
+  // workaround this by returning mtime if its newer than atime.
+  // https://github.com/containers/fuse-overlayfs/issues/259
+  //
+  // This should be a no-op on all other file systems, since atime should
+  // always be as new or newer than mtime.
+  auto ATime = toTimePoint(fs_st_atime, fs_st_atime_nsec);
+  auto MTime = getLastModificationTime();
+  if (MTime > ATime)
+    return MTime;
+  return ATime;
 }
 
 TimePoint<> basic_file_status::getLastModificationTime() const {


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