Amir Goldstein <[email protected]> writes: > On Wed, Jul 8, 2026 at 3:11 PM Luis Henriques <[email protected]> wrote: >> >> This patch adds a simple test that allows to verify that ACLs caching is >> working as expected. I.e. it verifies that, if FUSE_POSIX_ACL flag is set, >> user-space is only called once when accessing an inode ACL and that >> subsequent accesses are cached in the kernel. >> >> Signed-off-by: Luis Henriques <[email protected]> >> --- >> .../selftests/filesystems/fuse/.gitignore | 2 + >> .../selftests/filesystems/fuse/Makefile | 13 +- >> .../selftests/filesystems/fuse/acl_fs.c | 216 ++++++++++++++++++ >> .../selftests/filesystems/fuse/acl_test.sh | 66 ++++++ >> .../selftests/filesystems/fuse/setgetacl.c | 62 +++++ >> 5 files changed, 357 insertions(+), 2 deletions(-) >> create mode 100644 tools/testing/selftests/filesystems/fuse/acl_fs.c >> create mode 100755 tools/testing/selftests/filesystems/fuse/acl_test.sh >> create mode 100644 tools/testing/selftests/filesystems/fuse/setgetacl.c >> >> diff --git a/tools/testing/selftests/filesystems/fuse/.gitignore >> b/tools/testing/selftests/filesystems/fuse/.gitignore >> index cfdc5ca3ded4..1733ebb9d7fd 100644 >> --- a/tools/testing/selftests/filesystems/fuse/.gitignore >> +++ b/tools/testing/selftests/filesystems/fuse/.gitignore >> @@ -2,3 +2,5 @@ >> fuse_mnt >> fusectl_test >> symlink_fs >> +acl_fs >> +setgetacl >> diff --git a/tools/testing/selftests/filesystems/fuse/Makefile >> b/tools/testing/selftests/filesystems/fuse/Makefile >> index 342da0878006..3bbf9d837e9a 100644 >> --- a/tools/testing/selftests/filesystems/fuse/Makefile >> +++ b/tools/testing/selftests/filesystems/fuse/Makefile >> @@ -3,8 +3,8 @@ >> CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) >> >> TEST_GEN_PROGS := fusectl_test >> -TEST_PROGS := symlink_test.sh >> -TEST_GEN_FILES := fuse_mnt symlink_fs >> +TEST_PROGS := symlink_test.sh acl_test.sh >> +TEST_GEN_FILES := fuse_mnt symlink_fs acl_fs setgetacl >> >> include ../../lib.mk >> >> @@ -18,8 +18,17 @@ ifeq ($(VAR_LDLIBS),) >> VAR_LDLIBS := -lfuse3 -pthread >> endif >> >> +ACL_CFLAGS := $(shell pkg-config libacl --cflags 2>/dev/null) >> +ACL_LDLIBS := $(shell pkg-config libacl --libs 2>/dev/null) >> + >> $(OUTPUT)/fuse_mnt: CFLAGS += $(VAR_CFLAGS) >> $(OUTPUT)/fuse_mnt: LDLIBS += $(VAR_LDLIBS) >> >> $(OUTPUT)/symlink_fs: CFLAGS += $(VAR_CFLAGS) >> $(OUTPUT)/symlink_fs: LDLIBS += $(VAR_LDLIBS) >> + >> +$(OUTPUT)/acl_fs: CFLAGS += $(VAR_CFLAGS) >> +$(OUTPUT)/acl_fs: LDLIBS += $(VAR_LDLIBS) >> + >> +$(OUTPUT)/setgetacl: CFLAGS += $(ACL_CFLAGS) >> +$(OUTPUT)/setgetacl: LDLIBS += $(ACL_LDLIBS) >> diff --git a/tools/testing/selftests/filesystems/fuse/acl_fs.c >> b/tools/testing/selftests/filesystems/fuse/acl_fs.c >> new file mode 100644 >> index 000000000000..4b5e0073ab4f >> --- /dev/null >> +++ b/tools/testing/selftests/filesystems/fuse/acl_fs.c >> @@ -0,0 +1,216 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> + >> +/* >> + * Simple filesystem to test FUSE ACLs cache >> + * >> + * This is a simple FUSE filesystem that contains a single object (a file >> named >> + * 'file') and which allows to set the 'system.posix_acl_access' ACL on that >> + * object. Whenever this ACL is read from the FUSE filesystem, a counter is >> + * incremented. And value for this counter can be obtained from reading >> from >> + * this file. >> + * >> + * When ACLs are being cached (the '--cache' argument was used to mount this >> + * filesystem), this counter will only be incremented the first time the >> ACL is >> + * read, as the kernel won't be calling into user-space again until that >> cache >> + * is invalidated. >> + */ >> +#define FUSE_USE_VERSION FUSE_MAKE_VERSION(3, 12) >> + >> +#include <fuse_lowlevel.h> >> +#include <stdio.h> >> +#include <stdlib.h> >> +#include <string.h> >> +#include <errno.h> >> +#include <fcntl.h> >> +#include <time.h> >> +#include <sys/stat.h> >> +#include <sys/param.h> >> +#include <sys/xattr.h> >> + >> +#define FILE "file" >> +#define TIMEOUT 86400.0f >> + >> +static struct options { >> + int cache_acls; >> +} options; >> + >> +static const struct fuse_opt option_spec[] = { >> + { "--cache", offsetof(struct options, cache_acls), 1 }, >> + FUSE_OPT_END >> +}; >> + >> +static int getxattr_counter = 0; >> + >> +static void acl_init(void *userdata, struct fuse_conn_info *conn) >> +{ >> + if (options.cache_acls) >> + fuse_set_feature_flag(conn, FUSE_CAP_POSIX_ACL); >> + else >> + fuse_unset_feature_flag(conn, FUSE_CAP_POSIX_ACL); >> +} >> + >> +static int acl_stat(fuse_ino_t ino, struct stat *stbuf) >> +{ >> + char data[64]; >> + >> + stbuf->st_ino = ino; >> + switch (ino) { >> + case 1: >> + stbuf->st_mode = S_IFDIR | 0755; >> + stbuf->st_nlink = 2; >> + break; >> + case 42: >> + stbuf->st_mode = S_IFREG | 0444; >> + stbuf->st_nlink = 1; >> + stbuf->st_size = sprintf(data, "%d\n", getxattr_counter); >> + break; >> + default: >> + return -1; >> + } >> + >> + stbuf->st_uid = getuid(); >> + stbuf->st_gid = getgid(); >> + stbuf->st_atime = stbuf->st_mtime = stbuf->st_ctime = time(NULL); >> + >> + return 0; >> +} >> + >> +static void acl_lookup(fuse_req_t req, fuse_ino_t parent, const char *name) >> +{ >> + struct fuse_entry_param e; >> + >> + memset(&e, 0, sizeof(e)); >> + >> + if (parent != 1 || strcmp(name, FILE) != 0) >> + fuse_reply_err(req, ENOENT); >> + else { >> + e.ino = 42; >> + e.attr_timeout = TIMEOUT; >> + e.entry_timeout = TIMEOUT; >> + acl_stat(e.ino, &e.attr); >> + fuse_reply_entry(req, &e); >> + } >> +} >> + >> +static void acl_getattr(fuse_req_t req, fuse_ino_t ino, >> + struct fuse_file_info *fi) >> +{ >> + struct stat attr; >> + >> + memset(&attr, 0, sizeof(struct stat)); >> + if (acl_stat(ino, &attr) == -1) >> + fuse_reply_err(req, ENOENT); >> + else >> + fuse_reply_attr(req, &attr, TIMEOUT); >> +} >> + >> +static void acl_read(fuse_req_t req, fuse_ino_t ino, size_t size, >> + off_t off, struct fuse_file_info *fi) >> +{ >> + char data[64]; >> + int len; >> + >> + len = sprintf(data, "%d\n", getxattr_counter); >> + if (off < len) >> + fuse_reply_buf(req, data + off, MIN(len - off, size)); >> + else >> + fuse_reply_buf(req, NULL, 0); >> +} >> + >> +char *xattr_value = NULL; >> +size_t xattr_value_sz = 0; >> + >> +static void acl_setxattr(fuse_req_t req, fuse_ino_t ino, const char *name, >> + const char *value, size_t size, int flags) >> +{ >> + int ret = 0; >> + >> + if (ino != 42) >> + ret = ENOENT; >> + else if (!strcmp(name, "system.posix_acl_access")) { >> + if (xattr_value) >> + free(xattr_value); >> + xattr_value = malloc(size); >> + memcpy(xattr_value, value, size); >> + xattr_value_sz = size; >> + } else >> + ret = ENOTSUP; >> + >> + fuse_reply_err(req, ret); >> +} >> + >> +static void acl_getxattr(fuse_req_t req, fuse_ino_t ino, const char *name, >> + size_t size) >> +{ >> + if (ino != 42) >> + fuse_reply_err(req, ENOENT); >> + else if (!xattr_value || strcmp(name, "system.posix_acl_access")) >> + fuse_reply_err(req, ENODATA); >> + else if (size) { >> + fuse_reply_buf(req, xattr_value, xattr_value_sz); >> + getxattr_counter++; >> + } else >> + fuse_reply_xattr(req, xattr_value_sz); >> +} >> + >> +static const struct fuse_lowlevel_ops acl_op = { >> + .init = acl_init, >> + .lookup = acl_lookup, >> + .getattr = acl_getattr, >> + .getxattr = acl_getxattr, >> + .setxattr = acl_setxattr, >> + .read = acl_read, >> +}; >> + >> +int main(int argc, char *argv[]) >> +{ >> + struct fuse_session *se; >> + struct fuse_loop_config *config; >> + struct fuse_args args = FUSE_ARGS_INIT(argc, argv); >> + struct fuse_cmdline_opts opts; >> + int ret = -1; >> + >> + options.cache_acls = 0; >> + >> + if (fuse_parse_cmdline(&args, &opts) != 0) >> + return ret; >> + >> + if (opts.mountpoint == NULL) { >> + printf("usage: %s [options] <mountpoint>\n", argv[0]); >> + goto out_args; >> + } >> + >> + if (fuse_opt_parse(&args, &options, option_spec, NULL) == -1) >> + goto out_args; >> + >> + se = fuse_session_new(&args, &acl_op, sizeof(acl_op), NULL); >> + if (!se) >> + goto out_args; >> + if (fuse_set_signal_handlers(se)) >> + goto out_session; >> + if (fuse_session_mount(se, opts.mountpoint)) >> + goto out_signal; >> + >> + fuse_daemonize(opts.foreground); >> + if (opts.singlethread) { >> + ret = fuse_session_loop(se); >> + } else { >> + config = fuse_loop_cfg_create(); >> + fuse_loop_cfg_set_clone_fd(config, opts.clone_fd); >> + fuse_loop_cfg_set_max_threads(config, opts.max_threads); >> + ret = fuse_session_loop_mt(se, config); >> + fuse_loop_cfg_destroy(config); >> + config = NULL; >> + } >> + fuse_session_unmount(se); >> + >> +out_signal: >> + fuse_remove_signal_handlers(se); >> +out_session: >> + fuse_session_destroy(se); >> +out_args: >> + free(opts.mountpoint); >> + fuse_opt_free_args(&args); >> + >> + return ret; >> +} >> diff --git a/tools/testing/selftests/filesystems/fuse/acl_test.sh >> b/tools/testing/selftests/filesystems/fuse/acl_test.sh >> new file mode 100755 >> index 000000000000..9070c51c6784 >> --- /dev/null >> +++ b/tools/testing/selftests/filesystems/fuse/acl_test.sh >> @@ -0,0 +1,66 @@ >> +#!/bin/sh >> +# SPDX-License-Identifier: GPL-2.0 >> + >> +exit_cleanup() >> +{ >> + fusermount -u ./mnt >> + rmdir ./mnt >> +} >> + >> +assert_value () >> +{ >> + if [ $1 -ne $2 ]; then >> + echo "FAILED" >> + echo $3 >> + exit 1 >> + fi >> +} >> + >> +set -e >> + >> +trap exit_cleanup EXIT >> + >> +mkdir -p mnt >> + >> +#sudo su - >> +#cd /home/miguel/kernel/linux/tools/testing/selftests/filesystems/fuse >> +#dmesg -c > /dev/null >> +#tmux -S ./bla -f a >> +#./acl_fs -d --cache ./mnt >> +#setfacl -m u:daemon:r mnt/file >> +#getfacl mnt/file >> + >> +./acl_fs ./mnt >> + >> +echo -n "Testing ACLs without cache: " >> + >> +# set ACL >> +./setgetacl ACCESS u::rw-,g::rw-,o::rw-,u:nobody:r--,m::rw- mnt/file >> + >> +# When symlink caching is disabled every access to a symlink is expected to >> +# result in a call to user-space >> +for i in $(seq 1 10); do >> + ./setgetacl ACCESS mnt/file > /dev/null >> +done >> + >> +res=$(cat ./mnt/file) >> +assert_value $res $i "Got $res, expected $i" >> +echo "PASSED" >> + >> +fusermount -u ./mnt >> + >> +./acl_fs --cache ./mnt >> + >> +echo -n "Testing ACLs with cache: " >> + >> +# set ACL >> +./setgetacl ACCESS u::rw-,g::rw-,o::rw-,u:nobody:r--,m::rw- mnt/file >> + >> +# With caching enabled, there will be a single call into user-space >> +for i in $(seq 1 10); do >> + ./setgetacl ACCESS mnt/file > /dev/null >> +done >> +res=$(cat ./mnt/file) >> +assert_value $res 1 "Got $res, expected 1" >> + >> +echo "PASSED" >> diff --git a/tools/testing/selftests/filesystems/fuse/setgetacl.c >> b/tools/testing/selftests/filesystems/fuse/setgetacl.c >> new file mode 100644 >> index 000000000000..035e7daa1c5d >> --- /dev/null >> +++ b/tools/testing/selftests/filesystems/fuse/setgetacl.c >> @@ -0,0 +1,62 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> + >> +/* Simple ACL set/get wrapper */ >> + >> +#include <stdio.h> >> +#include <stdio.h> >> +#include <stdlib.h> >> +#include <string.h> >> +#include <sys/types.h> >> +#include <sys/acl.h> >> + >> +int main(int argc, char *argv[]) >> +{ >> + acl_t acl; >> + acl_type_t type; >> + char *buf; >> + >> + if ((argc != 3) && (argc != 4)) { >> + fprintf(stderr, "Usage: %s <acl type> [<value>] <file>\n", >> + argv[0]); >> + fprintf(stderr, "where <acl type> is ACCESS or DEFAULT\n"); >> + return 1; >> + } >> + >> + if (!strcmp(argv[1], "ACCESS")) >> + type = ACL_TYPE_ACCESS; >> + else if (!strcmp(argv[1], "DEFAULT")) >> + type = ACL_TYPE_DEFAULT; >> + else { >> + fprintf(stderr, "Invalid ACL type\n"); >> + return 1; >> + } >> + >> + if (argc == 3) { >> + /* Get ACL */ >> + acl = acl_get_file(argv[2], type); >> + if (acl == NULL) { >> + perror("acl_get_file"); >> + return 1; >> + } >> + buf = acl_to_text(acl, NULL); >> + if (buf == NULL) >> + perror("acl_from_text"); >> + else { >> + fprintf(stdout, "%s\n", buf); >> + acl_free(buf); >> + } >> + } else { >> + /* Set ACL */ >> + acl = acl_from_text(argv[2]); >> + if (acl == NULL) { >> + perror("acl_from_text"); >> + return 1; >> + } >> + if (acl_set_file(argv[3], type, acl) != 0) >> + perror("acl_set_file"); >> + } >> + >> + acl_free(acl); >> + >> + return 0; >> +} >> > > I think this test is already covered by > https://lore.kernel.org/linux-fsdevel/[email protected]/ > > If there is any missing coverage, it could be added to my test, > assuming that my test (which tests a regression) will be merged first.
Sure, that makes sense. I will make sure that any addition ACL testing is added to your selftest. To be honest, I saw your fix+selftest only *after* sending this RFC :-) Thanks a lot for your feedback, Amir. Cheers, -- Luís
