+
+/*
+ * Create a volatile file and open it for write:
+ * - file is created as a standard file in the directory
+ * - file does not appears in directory and directory mtime does not change
+ * - file is removed at close
+ * - file modes are rw-------, if user wants another one it must use fchmod()
+ * \param directory Directory where the file is created
+ * \param idx MDT index on which the file is created
+ * \param flags Std open flags
+ *
+ * \retval 0 on success.
+ * \retval -errno on error.
+ */
+int llapi_create_volatile_idx(char *directory, int idx, int mode)
+{
+ char file_path[PATH_MAX];
+ char filename[PATH_MAX];
+ int fd;
+ int random;
+ int rc;
+
+ fd = open("/dev/urandom", O_RDONLY);
+ if (fd < 0) {
+ llapi_error(LLAPI_MSG_ERROR, errno,
+ "Cannot open /dev/urandom\n");
+ return -errno;
+ }
+ rc = read(fd, &random, sizeof(random));
+ close(fd);
+ if (rc < sizeof(random)) {
+ llapi_error(LLAPI_MSG_ERROR, errno,
+ "Cannot read %d bytes from /dev/urandom\n",
+ sizeof(random));
+ return -errno;
+ }
+ if (idx == -1)
+ snprintf(filename, sizeof(filename),
+ LUSTRE_VOLATILE_HDR"::%.4X", random);
+ else
+ snprintf(filename, sizeof(filename),
+ LUSTRE_VOLATILE_IDX"%.4X", 0, random);
+
+ rc = snprintf(file_path, sizeof(file_path),
+ "%s/%s", directory, filename);
+ if (rc >= sizeof(file_path))
+ return -E2BIG;
+
+ fd = open(file_path, (O_RDWR | O_CREAT | mode), (S_IRUSR | S_IWUSR));
+ if (fd < 0) {
+ llapi_error(LLAPI_MSG_ERROR, errno,
+ "Cannot create volatile file %s in %s\n",
+ filename + LUSTRE_VOLATILE_HDR_LEN,
+ directory);
+ return -errno;
+ }
+ return fd;
+}
+
+/**
+ * Swap the layouts between 2 file descriptors
+ * the 2 files must be open in write
+ * first fd received the ioctl, second fd is passed as arg
+ * this is assymetric but avoid use of root path for ioctl
+ */
+int llapi_fswap_layouts(int fd1, int fd2, __u64 dv1, __u64 dv2, __u64 flags)
+{
+ struct lustre_swap_layouts lsl;
+ int rc;
+
+ srandom(time(NULL));
+ lsl.sl_fd = fd2;
+ lsl.sl_flags = flags;
+ lsl.sl_gid = random();
+ lsl.sl_dv1 = dv1;
+ lsl.sl_dv2 = dv2;
+ rc = ioctl(fd1, LL_IOC_LOV_SWAP_LAYOUTS, &lsl);
+ if (rc)
+ rc = -errno;
+ return rc;
+}
+
+/**
+ * Swap the layouts between 2 files
+ * the 2 files are open in write
+ */
+int llapi_swap_layouts(const char *path1, const char *path2,
+ __u64 dv1, __u64 dv2, __u64 flags)
+{
+ int fd1, fd2, rc;
+
+ fd1 = open(path1, O_WRONLY | O_LOV_DELAY_CREATE);
+ if (fd1 < 0) {
+ llapi_error(LLAPI_MSG_ERROR, -errno,
+ "error: cannot open for write %s",
+ path1);
+ return -errno;
+ }
+
+ fd2 = open(path2, O_WRONLY | O_LOV_DELAY_CREATE);
+ if (fd2 < 0) {
+ llapi_error(LLAPI_MSG_ERROR, -errno,
+ "error: cannot open for write %s",
+ path2);
+ close(fd1);
+ return -errno;
+ }
+
+ rc = llapi_fswap_layouts(fd1, fd2, dv1, dv2, flags);
+ if (rc < 0)
+ llapi_error(LLAPI_MSG_ERROR, rc,
+ "error: cannot swap layouts between %s and %s\n",
+ path1, path2);
+
+ close(fd1);
+ close(fd2);
+ return rc;
+}