Handle EINTR returned by Fallocate

Fallocate can return EINTR (interrupted system call) and does so
quite often when cpu profiling is enabled.

1 files changed, 15 insertions, 4 deletions

diff --git a/pathfs_frontend/file.go b/pathfs_frontend/file.go
index f2350cc..1470da2 100644
--- a/pathfs_frontend/file.go
+++ b/pathfs_frontend/file.go
@@ -97,9 +97,9 @@ func (f *file) createHeader() error {
 	// Prevent partially written (=corrupt) header by preallocating the space beforehand
 	f.fdLock.Lock()
 	defer f.fdLock.Unlock()
-	err := syscall.Fallocate(int(f.fd.Fd()), FALLOC_FL_KEEP_SIZE, 0, cryptfs.HEADER_LEN)
+	err := fallocateRetry(int(f.fd.Fd()), FALLOC_FL_KEEP_SIZE, 0, cryptfs.HEADER_LEN)
 	if err != nil {
-		cryptfs.Warn.Printf("createHeader: Fallocate failed: %s\n", err.Error())
+		cryptfs.Warn.Printf("createHeader: fallocateRetry failed: %s\n", err.Error())
 		return err
 	}
 
@@ -205,6 +205,17 @@ func (f *file) Read(buf []byte, off int64) (resultData fuse.ReadResult, code fus
 	return fuse.ReadResultData(out), status
 }
 
+// fallocateRetry - syscall.Fallocate() with retry for EINTR.
+func fallocateRetry(fd int, mode uint32, off int64, len int64) (err error) {
+	for {
+		err = syscall.Fallocate(fd, mode, off, len)
+		if err == syscall.EINTR {
+			continue
+		}
+		return err
+	}
+}
+
 const FALLOC_FL_KEEP_SIZE = 0x01
 
 // doWrite - encrypt "data" and write it to plaintext offset "off"
@@ -258,10 +269,10 @@ func (f *file) doWrite(data []byte, off int64) (uint32, fuse.Status) {
 
 		// Prevent partially written (=corrupt) blocks by preallocating the space beforehand
 		f.fdLock.Lock()
-		err := syscall.Fallocate(int(f.fd.Fd()), FALLOC_FL_KEEP_SIZE, int64(blockOffset), int64(blockLen))
+		err := fallocateRetry(int(f.fd.Fd()), FALLOC_FL_KEEP_SIZE, int64(blockOffset), int64(blockLen))
 		f.fdLock.Unlock()
 		if err != nil {
-			cryptfs.Warn.Printf("doWrite: Fallocate failed: %s\n", err.Error())
+			cryptfs.Warn.Printf("doWrite: fallocateRetry failed: %s\n", err.Error())
 			status = fuse.ToStatus(err)
 			break
 		}