gfapi: add new API glfs_dup() to copy a file descriptor

Duplicate a glfs_fd file descriptor. Inherit the internal
fd_t with a reference.

Change-Id: Ib30e9a46b608b9f78202957f4dab6ba6265a9ec0
BUG: 953694
Signed-off-by: Anand Avati <avati@redhat.com>
Reviewed-on: http://review.gluster.org/5109
Reviewed-by: Raghavendra Talur <rtalur@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>

1 files changed, 42 insertions, 0 deletions

diff --git a/api/src/glfs-fops.c b/api/src/glfs-fops.c
index 231db481b8e..66e7d69f14d 100644
--- a/api/src/glfs-fops.c
+++ b/api/src/glfs-fops.c
@@ -2882,3 +2882,45 @@ out:
 
 	return ret;
 }
+
+
+struct glfs_fd *
+glfs_dup (struct glfs_fd *glfd)
+{
+	xlator_t  *subvol = NULL;
+	fd_t      *fd = NULL;
+	glfs_fd_t *dupfd = NULL;
+	struct glfs *fs = NULL;
+
+	__glfs_entry_fd (glfd);
+
+	fs = glfd->fs;
+	subvol = glfs_active_subvol (fs);
+	if (!subvol) {
+		errno = EIO;
+		goto out;
+	}
+
+	fd = glfs_resolve_fd (fs, subvol, glfd);
+	if (!fd) {
+		errno = EBADFD;
+		goto out;
+	}
+
+	dupfd = glfs_fd_new (fs);
+	if (!dupfd) {
+		errno = ENOMEM;
+		goto out;
+	}
+
+	dupfd->fd = fd_ref (fd);
+out:
+	if (fd)
+		fd_unref (fd);
+	if (dupfd)
+		glfs_fd_bind (dupfd);
+
+	glfs_subvol_done (fs, subvol);
+
+	return dupfd;
+}