On Wed, Sep 4, 2024 at 7:57 PM Aleksa Sarai <cyphar@xxxxxxxxxx> wrote: > > Now that open_by_handle_at(2) can return u64 mount IDs, do some tests to > make sure they match properly as part of the regular open_by_handle > tests. Also, add automatic tests for the old u32 mount IDs as well. > > By default, we do mount ID checks but silently skip the tests if the > syscalls are not supported by the running kernel (to ensure the tests > continue to work for old kernels). We will add some tests explicitly > checking the new features (with no silent skipping) in a future patch. > > The u32 mount ID tests require STATX_MNT_ID (Linux 5.8), while the u64 > mount ID tests require STATX_MNT_ID_UNIQUE (Linux 6.9) and > AT_HANDLE_MNT_ID_UNIQUE (linux-next). > > Link: https://lore.kernel.org/all/20240828-exportfs-u64-mount-id-v3-0-10c2c4c16708@xxxxxxxxxx/ > Signed-off-by: Aleksa Sarai <cyphar@xxxxxxxxxx> Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx> > --- > Changed in v3: > - Make skipping completely silent in regular open_by_handle mode. [Amir Goldstein] > - Re-add -M to turn skipping into errors and add a new test that uses > -M, but is skipped on older kernels. [Amir Goldstein] > - v2: <https://lore.kernel.org/all/20240902164554.928371-1-cyphar@xxxxxxxxxx/> > Changed in v2: > - Remove -M argument and always do the mount ID tests. [Amir Goldstein] > - Do not error out if the kernel doesn't support STATX_MNT_ID_UNIQUE > or AT_HANDLE_MNT_ID_UNIQUE. [Amir Goldstein] > - v1: <https://lore.kernel.org/all/20240828103706.2393267-1-cyphar@xxxxxxxxxx/> > --- > src/open_by_handle.c | 132 +++++++++++++++++++++++++++++++++---------- > 1 file changed, 103 insertions(+), 29 deletions(-) > > diff --git a/src/open_by_handle.c b/src/open_by_handle.c > index 0f74ed08b1f0..920ec7d9170b 100644 > --- a/src/open_by_handle.c > +++ b/src/open_by_handle.c > @@ -87,6 +87,15 @@ Examples: > #include <errno.h> > #include <linux/limits.h> > #include <libgen.h> > +#include <stdint.h> > +#include <stdbool.h> > + > +#include <sys/stat.h> > +#include "statx.h" > + > +#ifndef AT_HANDLE_MNT_ID_UNIQUE > +# define AT_HANDLE_MNT_ID_UNIQUE 0x001 > +#endif > > #define MAXFILES 1024 > > @@ -108,6 +117,7 @@ void usage(void) > fprintf(stderr, "open_by_handle -a <test_dir> [N] - write data to test files after open by handle\n"); > fprintf(stderr, "open_by_handle -l <test_dir> [N] - create hardlinks to test files, drop caches and try to open by handle\n"); > fprintf(stderr, "open_by_handle -u <test_dir> [N] - unlink (hardlinked) test files, drop caches and try to open by handle\n"); > + fprintf(stderr, "open_by_handle -U <test_dir> [N] - verify the mount ID returned with AT_HANDLE_MNT_ID_UNIQUE is correct\n"); > fprintf(stderr, "open_by_handle -d <test_dir> [N] - unlink test files and hardlinks, drop caches and try to open by handle\n"); > fprintf(stderr, "open_by_handle -m <test_dir> [N] - rename test files, drop caches and try to open by handle\n"); > fprintf(stderr, "open_by_handle -p <test_dir> - create/delete and try to open by handle also test_dir itself\n"); > @@ -118,6 +128,94 @@ void usage(void) > exit(EXIT_FAILURE); > } > > +static int do_name_to_handle_at(const char *fname, struct file_handle *fh, > + int bufsz) > +{ > + int ret; > + int mntid_short; > + > + static bool skip_mntid, skip_mntid_unique; > + > + uint64_t statx_mntid_short = 0, statx_mntid_unique = 0; > + struct statx statxbuf; > + > + /* Get both the short and unique mount id. */ > + if (!skip_mntid) { > + if (xfstests_statx(AT_FDCWD, fname, 0, STATX_MNT_ID, &statxbuf) < 0) { > + fprintf(stderr, "%s: statx(STATX_MNT_ID): %m\n", fname); > + return EXIT_FAILURE; > + } > + if (!(statxbuf.stx_mask & STATX_MNT_ID)) > + skip_mntid = true; > + else > + statx_mntid_short = statxbuf.stx_mnt_id; > + } > + > + if (!skip_mntid_unique) { > + if (xfstests_statx(AT_FDCWD, fname, 0, STATX_MNT_ID_UNIQUE, &statxbuf) < 0) { > + fprintf(stderr, "%s: statx(STATX_MNT_ID_UNIQUE): %m\n", fname); > + return EXIT_FAILURE; > + } > + /* > + * STATX_MNT_ID_UNIQUE was added fairly recently in Linux 6.8, so if the > + * kernel doesn't give us a unique mount ID just skip it. > + */ > + if (!(statxbuf.stx_mask & STATX_MNT_ID_UNIQUE)) > + skip_mntid_unique = true; > + else > + statx_mntid_unique = statxbuf.stx_mnt_id; > + } > + > + fh->handle_bytes = bufsz; > + ret = name_to_handle_at(AT_FDCWD, fname, fh, &mntid_short, 0); > + if (bufsz < fh->handle_bytes) { > + /* Query the filesystem required bufsz and the file handle */ > + if (ret != -1 || errno != EOVERFLOW) { > + fprintf(stderr, "%s: unexpected result from name_to_handle_at: %d (%m)\n", fname, ret); > + return EXIT_FAILURE; > + } > + ret = name_to_handle_at(AT_FDCWD, fname, fh, &mntid_short, 0); > + } > + if (ret < 0) { > + fprintf(stderr, "%s: name_to_handle: %m\n", fname); > + return EXIT_FAILURE; > + } > + > + if (!skip_mntid) { > + if (mntid_short != (int) statx_mntid_short) { > + fprintf(stderr, "%s: name_to_handle_at returned a different mount ID to STATX_MNT_ID: %u != %lu\n", fname, mntid_short, statx_mntid_short); > + return EXIT_FAILURE; > + } > + } > + > + if (!skip_mntid_unique) { > + struct handle dummy_fh; > + uint64_t mntid_unique = 0; > + > + /* > + * Get the unique mount ID. We don't need to get another copy of the > + * handle so store it in a dummy struct. > + */ > + dummy_fh.fh.handle_bytes = fh->handle_bytes; > + ret = name_to_handle_at(AT_FDCWD, fname, &dummy_fh.fh, (int *) &mntid_unique, AT_HANDLE_MNT_ID_UNIQUE); > + if (ret < 0) { > + if (errno != EINVAL) { > + fprintf(stderr, "%s: name_to_handle_at(AT_HANDLE_MNT_ID_UNIQUE): %m\n", fname); > + return EXIT_FAILURE; > + } > + /* EINVAL means AT_HANDLE_MNT_ID_UNIQUE is not supported */ > + skip_mntid_unique = true; > + } else { > + if (mntid_unique != statx_mntid_unique) { > + fprintf(stderr, "%s: name_to_handle_at(AT_HANDLE_MNT_ID_UNIQUE) returned a different mount ID to STATX_MNT_ID_UNIQUE: %lu != %lu\n", fname, mntid_unique, statx_mntid_unique); > + return EXIT_FAILURE; > + } > + } > + } > + > + return 0; > +} > + > int main(int argc, char **argv) > { > int i, c; > @@ -130,7 +228,7 @@ int main(int argc, char **argv) > char fname2[PATH_MAX]; > char *test_dir; > char *mount_dir; > - int mount_fd, mount_id; > + int mount_fd; > char *infile = NULL, *outfile = NULL; > int in_fd = 0, out_fd = 0; > int numfiles = 1; > @@ -305,21 +403,9 @@ int main(int argc, char **argv) > return EXIT_FAILURE; > } > } else { > - 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); > + ret = do_name_to_handle_at(fname, &handle[i].fh, bufsz); > + if (ret) > return EXIT_FAILURE; > - } > } > if (keepopen) { > /* Open without close to keep unlinked files around */ > @@ -347,21 +433,9 @@ int main(int argc, char **argv) > return EXIT_FAILURE; > } > } else { > - 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); > + ret = do_name_to_handle_at(test_dir, &dir_handle.fh, bufsz); > + if (ret) > return EXIT_FAILURE; > - } > } > if (out_fd) { > ret = write(out_fd, (char *)&dir_handle, sizeof(*handle)); > -- > 2.46.0 >
