posix: Set correct d_type for readdirp() calls

dirent.d_type can contain the type of the directory entry. The 'd_type'
struct member in dirent is present in Linux and many BSD flavours.
However, filling d_type with correct value requires support from the
underlying filesystem. If not, d_type is set to DT_UNKNOWN. XFS added
support for d_type as part of their newer version 5 on-disk format.
However, this requires Linux >= 3.15, xfsprogs >= 3.2.0 and the bricks
to be formatted using the new format.

This patch enables posix xlator to set d_type to the right value even
when the underlying filesystem does not support it. d_type can be set
using information previously fetched by stat() on the dir entry.
This will aid FUSE applications to leverage d_type to avoid the expense
of calling lstat() if further actions depend on the type of the file.

Refer `man 3 readdir` and `man 2 getdents`

BUG: 1175711
Change-Id: Ic5a262fe4c64122726b4fae2d1bea375c559ca04
Signed-off-by: Prashanth Pai <ppai@redhat.com>
Reviewed-on: http://review.gluster.org/14095
Smoke: Gluster Build System <jenkins@build.gluster.com>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/tests/bugs/posix/bug-1175711.c b/tests/bugs/posix/bug-1175711.c
new file mode 100644
index 00000000000..fbbea3f636b
--- /dev/null
+++ b/tests/bugs/posix/bug-1175711.c
@@ -0,0 +1,37 @@
+#include <stdio.h>
+#include <dirent.h>
+#include <string.h>
+#include <assert.h>
+
+int
+main(int argc, char **argv)
+{
+        DIR *dir = NULL;
+        struct dirent *entry = NULL;
+        int ret = 0;
+        char *path = NULL;
+
+        assert (argc == 2);
+        path = argv[1];
+
+        dir = opendir(path);
+        if (!dir) {
+                printf("opendir(%s) failed.\n", path);
+                return -1;
+        }
+
+#ifdef _DIRENT_HAVE_D_TYPE
+        while ((entry = readdir(dir)) != NULL) {
+                if (entry->d_type == DT_UNKNOWN) {
+                        printf("d_type found to be DT_UNKNOWN\n");
+                        ret = -1;
+                        break;
+                }
+        }
+#endif
+
+        if (dir)
+                closedir(dir);
+
+        return ret;
+}