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

Amir Goldstein
2017-04-18T18:17:20Z

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