ANDROID: fuse-bpf: Add partial flock support
This adds passthrough support for flock on fuse-bpf files. It does not
give any control via a bpf filter. The flock will act as though it was
taken on the lower file.
Bug: 289882899
Bug: 296641006
Test: fuse_test -t32 (flock_test)
Signed-off-by: Daniel Rosenberg <drosen@google.com>
(cherry picked from https://android-review.googlesource.com/q/commit:6d6ee09bb74fe3b86cfdc87da6f7a40c82f7b36d)
Merged-In: Iba0b9630766cedbd3195532c5e929891593cfe30
Change-Id: Iba0b9630766cedbd3195532c5e929891593cfe30
diff --git a/fs/fuse/backing.c b/fs/fuse/backing.c
index 5665ff7..5703be7 100644
--- a/fs/fuse/backing.c
+++ b/fs/fuse/backing.c
@@ -991,6 +991,20 @@
return ERR_PTR(fwio->ret);
}
+int fuse_file_flock_backing(struct file *file, int cmd, struct file_lock *fl)
+{
+ struct fuse_file *ff = file->private_data;
+ struct file *backing_file = ff->backing_file;
+ int error;
+
+ fl->fl_file = backing_file;
+ if (backing_file->f_op->flock)
+ error = backing_file->f_op->flock(backing_file, cmd, fl);
+ else
+ error = locks_lock_file_wait(backing_file, fl);
+ return error;
+}
+
ssize_t fuse_backing_mmap(struct file *file, struct vm_area_struct *vma)
{
int ret;
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 3963816..39a00074 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -2663,12 +2663,18 @@
{
struct inode *inode = file_inode(file);
struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_file *ff = file->private_data;
int err;
+#ifdef CONFIG_FUSE_BPF
+ /* TODO - this is simply passthrough, not a proper BPF filter */
+ if (ff->backing_file)
+ return fuse_file_flock_backing(file, cmd, fl);
+#endif
+
if (fc->no_flock) {
err = locks_lock_file_wait(file, fl);
} else {
- struct fuse_file *ff = file->private_data;
/* emulate flock with POSIX locks */
ff->flock = true;
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 31f6fbbd..f7d214b 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -1634,6 +1634,7 @@
void *fuse_file_write_iter_finalize(struct fuse_bpf_args *fa,
struct kiocb *iocb, struct iov_iter *from);
+int fuse_file_flock_backing(struct file *file, int cmd, struct file_lock *fl);
ssize_t fuse_backing_mmap(struct file *file, struct vm_area_struct *vma);
int fuse_file_fallocate_initialize(struct fuse_bpf_args *fa,
diff --git a/tools/testing/selftests/filesystems/fuse/fuse_test.c b/tools/testing/selftests/filesystems/fuse/fuse_test.c
index c23f75b..a1a0929 100644
--- a/tools/testing/selftests/filesystems/fuse/fuse_test.c
+++ b/tools/testing/selftests/filesystems/fuse/fuse_test.c
@@ -12,6 +12,7 @@
#include <string.h>
#include <unistd.h>
+#include <sys/file.h>
#include <sys/inotify.h>
#include <sys/mman.h>
#include <sys/mount.h>
@@ -1336,6 +1337,50 @@
return result;
}
+static int flock_test(const char *mount_dir)
+{
+ const char *file = "file";
+ int result = TEST_FAILURE;
+ int src_fd = -1;
+ int fuse_dev = -1;
+ int fd = -1, fd2 = -1;
+ int backing_fd = -1;
+ char *addr = NULL;
+
+ TEST(src_fd = open(ft_src, O_DIRECTORY | O_RDONLY | O_CLOEXEC),
+ src_fd != -1);
+ TESTEQUAL(mount_fuse(mount_dir, -1, src_fd, &fuse_dev), 0);
+ TEST(fd = s_open(s_path(s(mount_dir), s(file)),
+ O_CREAT | O_RDWR | O_CLOEXEC, 0777),
+ fd != -1);
+ TEST(fd2 = s_open(s_path(s(mount_dir), s(file)),
+ O_RDWR | O_CLOEXEC, 0777),
+ fd2 != -1);
+ TESTSYSCALL(flock(fd, LOCK_EX | LOCK_NB));
+ TESTCONDERR((flock(fd2, LOCK_EX | LOCK_NB)) == -1);
+ TESTCOND(errno == EAGAIN);
+ TESTSYSCALL(flock(fd, LOCK_UN));
+ TESTSYSCALL(flock(fd2, LOCK_EX | LOCK_NB));
+ TEST(backing_fd = s_open(s_path(s(ft_src), s(file)),
+ O_RDONLY | O_CLOEXEC),
+ backing_fd != -1);
+ TESTCONDERR((flock(backing_fd, LOCK_EX | LOCK_NB)) == -1);
+ TESTCOND(errno == EAGAIN);
+ close(fd2);
+ fd2 = 0;
+ TESTSYSCALL(flock(backing_fd, LOCK_EX | LOCK_NB));
+
+ result = TEST_SUCCESS;
+out:
+ close(fd);
+ close(fd2);
+ close(backing_fd);
+ umount(mount_dir);
+ close(fuse_dev);
+ close(src_fd);
+ return result;
+}
+
static int readdir_perms_test(const char *mount_dir)
{
int result = TEST_FAILURE;
@@ -2091,6 +2136,7 @@
MAKE_TEST(bpf_test_no_readdirplus_without_nodeid),
MAKE_TEST(bpf_test_revalidate_handle_backing_fd),
MAKE_TEST(bpf_test_lookup_postfilter),
+ MAKE_TEST(flock_test),
};
#undef MAKE_TEST
