[PATCH 2/4] src/open_by_handle: flexible usage options

[Amir Goldstein <amir73il@gmail.com>]

More usage options for testing open_by_handle, which are needed
for testing stable handles across copy up in overlayfs.

usage: open_by_handle [-c|-l|-u|-d] <test_dir> [num_files]

Examples:

1. Create N test files (nlink=1) under test_dir and exit:
 $ open_by_handle -c <test_dir> [N]

2. Get file handles, drop caches and try to open by handle
   (expects success):
 $ open_by_handle <test_dir> [N]

3. Get file handles, create hardlinks to test files (nlink=2),
   drop caches and try to open by handle (expects success):
 $ open_by_handle -l <test_dir> [N]

4. Get file handles, unlink test files w/o the hardlinks (nlink=1),
   drop caches and try to open by handle (expects success):
 $ open_by_handle -u <test_dir> [N]

5. Get file handles, unlink test files and hardlinks (nlink=0),
   drop caches and try to open by handle (expects failure):
 $ open_by_handle -d <test_dir> [N]

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 src/open_by_handle.c | 93 ++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 80 insertions(+), 13 deletions(-)

diff --git a/src/open_by_handle.c b/src/open_by_handle.c
index 8f04865..c33a4aa 100644
--- a/src/open_by_handle.c
+++ b/src/open_by_handle.c
@@ -37,12 +37,12 @@
 #include <errno.h>
 #include <linux/limits.h>
 
-#define NUMFILES 1024
+#define MAXFILES 1024
 
 struct handle {
 	struct file_handle fh;
 	unsigned char fid[MAX_HANDLE_SZ];
-} handle[NUMFILES];
+} handle[MAXFILES];
 
 int main(int argc, char **argv)
 {
@@ -51,18 +51,60 @@ int main(int argc, char **argv)
 	int	ret;
 	int	failed = 0;
 	char	fname[PATH_MAX];
+	char	fname2[PATH_MAX];
 	char	*test_dir;
 	int	mount_fd, mount_id;
+	int	argi = 1, numfiles = 1;
+	int	create = 0, delete = 0, nlink = 1;
 
-	if (argc != 2) {
-		fprintf(stderr, "usage: open_by_handle <test_dir>\n");
+	if (argc < 2 || argc > 4) {
+usage:
+		fprintf(stderr, "usage: open_by_handle [-c|-l|-u|-d] <test_dir> [num_files]\n");
+		fprintf(stderr, "\n");
+		fprintf(stderr, "open_by_handle -c <test_dir> [N] - create N test files under test_dir, get file handles and exit\n");
+		fprintf(stderr, "open_by_handle    <test_dir> [N] - get file handles, drop caches and try to open by handle (expects success)\n");
+		fprintf(stderr, "open_by_handle -l <test_dir> [N] - get file handles, create hardlinks to test files (nlink=2), drop caches and try to open by handle (expects success)\n");
+		fprintf(stderr, "open_by_handle -u <test_dir> [N] - get file handles, unlink test files w/o hardlinks (nlink=1), drop caches and try to open by handle (expects success)\n");
+		fprintf(stderr, "open_by_handle -d <test_dir> [N] - get file handles, unlink test files and hardlinks (nlink=0), drop caches and try to open by handle (expects failure)\n");
 		return EXIT_FAILURE;
 	}
 
-	test_dir = argv[1];
+	if (argv[1][0] == '-') {
+		if (argv[1][2])
+			goto usage;
+		switch (argv[1][1]) {
+		case 'c':
+			create = 1;
+			break;
+		case 'l':
+			nlink = 2;
+			break;
+		case 'u':
+			delete = 1;
+			nlink = 1;
+			break;
+		case 'd':
+			delete = 1;
+			nlink = 0;
+			break;
+		default:
+			fprintf(stderr, "illegal option '%s'\n", argv[1]);
+		case 'h':
+			goto usage;
+		}
+		argi++;
+	}
+	test_dir = argv[argi++];
+	if (argc > argi)
+		numfiles = atoi(argv[argi]);
+	if (!numfiles || numfiles > MAXFILES) {
+		fprintf(stderr, "illegal value '%s' for num_files\n", argv[argi]);
+		goto usage;
+	}
+
 	mount_fd = open(test_dir, O_RDONLY|O_DIRECTORY);
 	if (mount_fd < 0) {
-		perror("open test_dir");
+		perror(test_dir);
 		return EXIT_FAILURE;
 	}
 
@@ -70,8 +112,9 @@ int main(int argc, char **argv)
 	 * create a large number of files to force allocation of new inode
 	 * chunks on disk.
 	 */
-	for (i=0; i < NUMFILES; i++) {
+	for (i=0; create && i < numfiles; i++) {
 		sprintf(fname, "%s/file%06d", test_dir, i);
+		sprintf(fname2, "%s/link%06d", test_dir, i);
 		fd = open(fname, O_RDWR | O_CREAT | O_TRUNC, 0644);
 		if (fd < 0) {
 			printf("Warning (%s,%d), open(%s) failed.\n", __FILE__, __LINE__, fname);
@@ -79,13 +122,14 @@ int main(int argc, char **argv)
 			return EXIT_FAILURE;
 		}
 		close(fd);
+		ret = unlink(fname2);
 	}
 
 	/* sync to get the new inodes to hit the disk */
 	sync();
 
 	/* create the handles */
-	for (i=0; i < NUMFILES; i++) {
+	for (i=0; i < numfiles; i++) {
 		sprintf(fname, "%s/file%06d", test_dir, i);
 		handle[i].fh.handle_bytes = MAX_HANDLE_SZ;
 		ret = name_to_handle_at(AT_FDCWD, fname, &handle[i].fh, &mount_id, 0);
@@ -95,14 +139,32 @@ int main(int argc, char **argv)
 		}
 	}
 
+	/* after creating test set only check that fs supports exportfs */
+	if (create)
+		return EXIT_SUCCESS;
+
+	/* hardlink the files */
+	for (i=0; nlink > 1 && i < numfiles; i++) {
+		sprintf(fname, "%s/file%06d", test_dir, i);
+		sprintf(fname2, "%s/link%06d", test_dir, i);
+		ret = link(fname, fname2);
+		if (ret < 0) {
+			perror("link");
+			return EXIT_FAILURE;
+		}
+	}
+
 	/* unlink the files */
-	for (i=0; i < NUMFILES; i++) {
+	for (i=0; delete && i < numfiles; i++) {
 		sprintf(fname, "%s/file%06d", test_dir, i);
+		sprintf(fname2, "%s/link%06d", test_dir, i);
 		ret = unlink(fname);
 		if (ret < 0) {
 			perror("unlink");
 			return EXIT_FAILURE;
 		}
+		if (!nlink)
+			ret = unlink(fname2);
 	}
 
 	/* sync to get log forced for unlink transactions to hit the disk */
@@ -126,17 +188,22 @@ int main(int argc, char **argv)
 	 * now try to open the files by the stored handles. Expecting ENOENT
 	 * for all of them.
 	 */
-	for (i=0; i < NUMFILES; i++) {
+	for (i=0; i < numfiles; i++) {
 		errno = 0;
 		fd = open_by_handle_at(mount_fd, &handle[i].fh, O_RDWR);
-		if (fd < 0 && (errno == ENOENT || errno == ESTALE)) {
+		if (nlink && fd >= 0) {
+			close(fd);
+			continue;
+		} else if (!nlink && fd < 0 && (errno == ENOENT || errno == ESTALE)) {
 			continue;
 		}
 		if (fd >= 0) {
 			printf("open_by_handle(%d) opened an unlinked file!\n", i);
 			close(fd);
-		} else
-			printf("open_by_handle(%d) returned %d incorrectly on an unlinked file!\n", i, errno);
+		} else {
+			printf("open_by_handle(%d) returned %d incorrectly on %s file!\n", i, errno,
+					nlink ? "a linked" : "an unlinked");
+		}
 		failed++;
 	}
 	if (failed)
-- 
2.7.4