open_by_handle: add option -z to query file handle size

Instead of using MAX_HANDLE_SZ, query the filesystem buffer size
and use that buffer size to get the file handle.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

diff --git a/src/open_by_handle.c b/src/open_by_handle.c
index 4fdfacd7cab3a7d27f495925b7fcf29c38e65a16..0f74ed08b1f0010cd8fb9796c447972baddc0aa3 100644 (file)
--- a/src/open_by_handle.c
+++ b/src/open_by_handle.c
@@ -114,6 +114,7 @@ void usage(void)
        fprintf(stderr, "open_by_handle -i <handles_file> <test_dir> [N] - read test files handles from file and try to open by handle\n");
        fprintf(stderr, "open_by_handle -o <handles_file> <test_dir> [N] - get file handles of test files and write handles to file\n");
        fprintf(stderr, "open_by_handle -s <test_dir> [N] - wait in sleep loop after opening files by handle to keep them open\n");
+       fprintf(stderr, "open_by_handle -z <test_dir> [N] - query filesystem required buffer size\n");
        exit(EXIT_FAILURE);
 }
 
@@ -136,11 +137,12 @@ int main(int argc, char **argv)
        int     create = 0, delete = 0, nlink = 1, move = 0;
        int     rd = 0, wr = 0, wrafter = 0, parent = 0;
        int     keepopen = 0, drop_caches = 1, sleep_loop = 0;
+       int     bufsz = MAX_HANDLE_SZ;
 
        if (argc < 2)
                usage();
 
-       while ((c = getopt(argc, argv, "cludmrwapknhi:o:s")) != -1) {
+       while ((c = getopt(argc, argv, "cludmrwapknhi:o:sz")) != -1) {
                switch (c) {
                case 'c':
                        create = 1;
@@ -199,6 +201,9 @@ int main(int argc, char **argv)
                case 's':
                        sleep_loop = 1;
                        break;
+               case 'z':
+                       bufsz = 0;
+                       break;
                default:
                        fprintf(stderr, "illegal option '%s'\n", argv[optind]);
                case 'h':
@@ -300,8 +305,16 @@ int main(int argc, char **argv)
                                return EXIT_FAILURE;
                        }
                } else {
-                       handle[i].fh.handle_bytes = MAX_HANDLE_SZ;
+                       handle[i].fh.handle_bytes = bufsz;
                        ret = name_to_handle_at(AT_FDCWD, fname, &handle[i].fh, &mount_id, 0);
+                       if (bufsz < handle[i].fh.handle_bytes) {
+                               /* Query the filesystem required bufsz and the file handle */
+                               if (ret != -1 || errno != EOVERFLOW) {
+                                       fprintf(stderr, "Unexpected result from name_to_handle_at(%s)\n", fname);
+                                       return EXIT_FAILURE;
+                               }
+                               ret = name_to_handle_at(AT_FDCWD, fname, &handle[i].fh, &mount_id, 0);
+                       }
                        if (ret < 0) {
                                strcat(fname, ": name_to_handle");
                                perror(fname);
@@ -334,8 +347,16 @@ int main(int argc, char **argv)
                                return EXIT_FAILURE;
                        }
                } else {
-                       dir_handle.fh.handle_bytes = MAX_HANDLE_SZ;
+                       dir_handle.fh.handle_bytes = bufsz;
                        ret = name_to_handle_at(AT_FDCWD, test_dir, &dir_handle.fh, &mount_id, 0);
+                       if (bufsz < dir_handle.fh.handle_bytes) {
+                               /* Query the filesystem required bufsz and the file handle */
+                               if (ret != -1 || errno != EOVERFLOW) {
+                                       fprintf(stderr, "Unexpected result from name_to_handle_at(%s)\n", dname);
+                                       return EXIT_FAILURE;
+                               }
+                               ret = name_to_handle_at(AT_FDCWD, test_dir, &dir_handle.fh, &mount_id, 0);
+                       }
                        if (ret < 0) {
                                strcat(dname, ": name_to_handle");
                                perror(dname);