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authorJakob Unterwurzacher2021-08-11 20:21:32 +0200
committerJakob Unterwurzacher2021-08-11 20:23:35 +0200
commit2d386fc92e88be5384d1654db5d6e23ef4682354 (patch)
tree32ad6c71cad91bc64f162d81ce7e64903b6e6b4f /internal/syscallcompat
parent0c16616117e9866cc49adc85738e3c9e3adf413a (diff)
syscallcompat: move quirks logic here & fix darwin
We need to look at f_fstypename acc. to https://stackoverflow.com/a/52299141/1380267 : > As filesystem type numbers are now assigned at runtime in > recent versions of MacOS, you must use f_fstypename to > determine the type. https://github.com/rfjakob/gocryptfs/issues/585
Diffstat (limited to 'internal/syscallcompat')
-rw-r--r--internal/syscallcompat/quirks.go20
-rw-r--r--internal/syscallcompat/quirks_darwin.go41
-rw-r--r--internal/syscallcompat/quirks_linux.go36
3 files changed, 97 insertions, 0 deletions
diff --git a/internal/syscallcompat/quirks.go b/internal/syscallcompat/quirks.go
new file mode 100644
index 0000000..60d584d
--- /dev/null
+++ b/internal/syscallcompat/quirks.go
@@ -0,0 +1,20 @@
+package syscallcompat
+
+import (
+ "github.com/rfjakob/gocryptfs/internal/tlog"
+)
+
+const (
+ // QuirkBrokenFalloc means the falloc is broken.
+ // Preallocation on Btrfs is broken ( https://github.com/rfjakob/gocryptfs/issues/395 )
+ // and slow ( https://github.com/rfjakob/gocryptfs/issues/63 ).
+ QuirkBrokenFalloc = uint64(1 << iota)
+ // QuirkDuplicateIno1 means that we have duplicate inode numbers.
+ // On MacOS ExFAT, all empty files share inode number 1:
+ // https://github.com/rfjakob/gocryptfs/issues/585
+ QuirkDuplicateIno1
+)
+
+func logQuirk(s string) {
+ tlog.Info.Printf(tlog.ColorYellow + "DetectQuirks: " + s + tlog.ColorReset)
+}
diff --git a/internal/syscallcompat/quirks_darwin.go b/internal/syscallcompat/quirks_darwin.go
new file mode 100644
index 0000000..f4e7e71
--- /dev/null
+++ b/internal/syscallcompat/quirks_darwin.go
@@ -0,0 +1,41 @@
+package syscallcompat
+
+import (
+ "golang.org/x/sys/unix"
+
+ "github.com/rfjakob/gocryptfs/internal/tlog"
+)
+
+func DetectQuirks(cipherdir string) (q uint64) {
+ const (
+ // From https://github.com/rfjakob/gocryptfs/issues/585#issuecomment-887370065
+ FstypenameExfat = "exfat"
+ )
+
+ var st unix.Statfs_t
+ err := unix.Statfs(cipherdir, &st)
+ if err != nil {
+ tlog.Warn.Printf("DetectQuirks: Statfs on %q failed: %v", cipherdir, err)
+ return 0
+ }
+
+ // Convert null-terminated st.Fstypename int8 array to string
+ var buf []byte
+ for _, v := range st.Fstypename {
+ if v == 0 {
+ break
+ }
+ buf = append(buf, byte(v))
+ }
+ fstypename := string(buf)
+ tlog.Debug.Printf("DetectQuirks: Fstypename=%q\n", fstypename)
+
+ // On MacOS ExFAT, all empty files share inode number 1:
+ // https://github.com/rfjakob/gocryptfs/issues/585
+ if fstypename == FstypenameExfat {
+ logQuirk("ExFAT detected, disabling hard links. See https://github.com/rfjakob/gocryptfs/issues/585 for why.")
+ q |= QuirkDuplicateIno1
+ }
+
+ return q
+}
diff --git a/internal/syscallcompat/quirks_linux.go b/internal/syscallcompat/quirks_linux.go
new file mode 100644
index 0000000..ffdbfab
--- /dev/null
+++ b/internal/syscallcompat/quirks_linux.go
@@ -0,0 +1,36 @@
+package syscallcompat
+
+import (
+ "golang.org/x/sys/unix"
+
+ "github.com/rfjakob/gocryptfs/internal/tlog"
+)
+
+// DetectQuirks decides if there are known quirks on the backing filesystem
+// that need to be workarounded.
+//
+// Tested by tests/root_test.TestBtrfsQuirks
+func DetectQuirks(cipherdir string) (q uint64) {
+ const (
+ // From Linux' man statfs
+ BTRFS_SUPER_MAGIC = 0x9123683e
+ )
+
+ var st unix.Statfs_t
+ err := unix.Statfs(cipherdir, &st)
+ if err != nil {
+ tlog.Warn.Printf("DetectQuirks: Statfs on %q failed: %v", cipherdir, err)
+ return 0
+ }
+
+ // Preallocation on Btrfs is broken ( https://github.com/rfjakob/gocryptfs/issues/395 )
+ // and slow ( https://github.com/rfjakob/gocryptfs/issues/63 ).
+ //
+ // Cast to uint32 avoids compile error on arm: "constant 2435016766 overflows int32"
+ if uint32(st.Type) == BTRFS_SUPER_MAGIC {
+ logQuirk("Btrfs detected, forcing -noprealloc. See https://github.com/rfjakob/gocryptfs/issues/395 for why.")
+ q |= QuirkBrokenFalloc
+ }
+
+ return q
+}