ignore FS_IOC_FIEMAP failure with ENOTSUPP

Lustre 2.15.6 can return ENOTSUPP (524) in response to an FS_IOC_FIEMAP
ioctl() call, for a file striped a certain way.  This is a bug, it
should return EOPNOTSUPP (95).

The file can still be copied, fiemap just can't tell us where the holes
are.

A brief survey using google searches suggests ENOTSUPP (524) was
historically intended for use internal to the kernel or drivers, but has
occasionally been returned to users by different software, in ways that
have meaning similar to ENOTSUP.

Ignore the error as with ENOTSUP (95) so the file is copied without the
use of fiemap.

Notify the user that the copied file is not sparse.

Fixes #644

Signed-off-by: Olaf Faaland <[email protected]>

Author: ofaaland

src/common/mfu_errors.h

@@ -20,6 +20,10 @@ static inline int mfu_errno2rc(int err)
     return -1;
 }
 
+/* Non-standard error code returned by syscalls or external libs */
+/* Returned by ioctl(FIEMAP) with Lustre 2.15.6, should be 95 ENOTSUP */
+#define MFU_ERR_ENOTSUPP 524
+
 /* Generic error codes */
 #define MFU_ERR           1000
 #define MFU_ERR_INVAL_ARG 1001

src/common/mfu_flist_copy.c

@@ -57,6 +57,7 @@
 
 #include "mfu.h"
 #include "mfu_flist_internal.h"
+#include "mfu_errors.h"
 #include "strmap.h"
 
 #ifdef LUSTRE_SUPPORT
@@ -1933,8 +1934,9 @@ static int mfu_copy_file_fiemap(
     }
 
     if (ioctl(mfu_src_file->fd, FS_IOC_FIEMAP, fiemap) < 0) {
-        if (errno == ENOTSUP) {
-            /* silently ignore */
+        if (errno == ENOTSUP || errno == MFU_ERR_ENOTSUPP) {
+            MFU_LOG(MFU_LOG_INFO, "Destination file not sparse; FIEMAP not supported for src '%s'",
+                    src, errno, strerror(errno));
         } else {
             MFU_LOG(MFU_LOG_ERR, "fiemap ioctl() failed for src '%s' (errno=%d %s)",
                     src, errno, strerror(errno));