fusefs: correctly set lock owner during FUSE_SETLK

During FUSE_SETLK, the owner field should uniquely identify the calling
process.  The fusefs module now sets it to the process's pid.
Previously, it expected the calling process to set it directly, which
was wrong.

libfuse also apparently expects the owner field to be set during
FUSE_GETLK, though I'm not sure why.

PR:		256005
Reported by:	Agata <chogata@moosefs.pro>
MFC after:	2 weeks
Reviewed by:	pfg
Differential Revision: https://reviews.freebsd.org/D30622

sys/fs/fuse/fuse_vnops.c

@@ -466,14 +466,14 @@ fuse_vnop_advlock(struct vop_advlock_args *ap)
 	fdisp_make_vp(&fdi, op, vp, td, cred);
 	fli = fdi.indata;
 	fli->fh = fufh->fh_id;
-	fli->owner = fl->l_pid;
+	fli->owner = td->td_proc->p_pid;
 	fli->lk.start = fl->l_start;
 	if (fl->l_len != 0)
 		fli->lk.end = fl->l_start + fl->l_len - 1;
 	else
 		fli->lk.end = INT64_MAX;
 	fli->lk.type = fl->l_type;
-	fli->lk.pid = fl->l_pid;
+	fli->lk.pid = td->td_proc->p_pid;
 
 	err = fdisp_wait_answ(&fdi);
 	fdisp_destroy(&fdi);

tests/sys/fs/fusefs/locks.cc

@@ -228,7 +228,7 @@ TEST_F(GetlkFallback, local)
 	ASSERT_LE(0, fd) << strerror(errno);
 	fl.l_start = 10;
 	fl.l_len = 1000;
-	fl.l_pid = getpid();
+	fl.l_pid = 0;
 	fl.l_type = F_RDLCK;
 	fl.l_whence = SEEK_SET;
 	fl.l_sysid = 0;
@@ -247,7 +247,7 @@ TEST_F(Getlk, no_locks)
 	uint64_t ino = 42;
 	struct flock fl;
 	int fd;
-	pid_t pid = 1234;
+	pid_t pid = getpid();
 
 	expect_lookup(RELPATH, ino);
 	expect_open(ino, 0, 1);
@@ -256,11 +256,16 @@ TEST_F(Getlk, no_locks)
 			return (in.header.opcode == FUSE_GETLK &&
 				in.header.nodeid == ino &&
 				in.body.getlk.fh == FH &&
+				/*
+				 * Though it seems useless, libfuse expects the
+				 * owner and pid fields to be set during
+				 * FUSE_GETLK.
+				 */
 				in.body.getlk.owner == (uint32_t)pid &&
+				in.body.getlk.lk.pid == (uint64_t)pid &&
 				in.body.getlk.lk.start == 10 &&
 				in.body.getlk.lk.end == 1009 &&
-				in.body.getlk.lk.type == F_RDLCK &&
-				in.body.getlk.lk.pid == (uint64_t)pid);
+				in.body.getlk.lk.type == F_RDLCK);
 		}, Eq(true)),
 		_)
 	).WillOnce(Invoke(ReturnImmediate([=](auto in, auto& out) {
@@ -273,7 +278,7 @@ TEST_F(Getlk, no_locks)
 	ASSERT_LE(0, fd) << strerror(errno);
 	fl.l_start = 10;
 	fl.l_len = 1000;
-	fl.l_pid = pid;
+	fl.l_pid = 0;
 	fl.l_type = F_RDLCK;
 	fl.l_whence = SEEK_SET;
 	fl.l_sysid = 0;
@@ -290,7 +295,7 @@ TEST_F(Getlk, lock_exists)
 	uint64_t ino = 42;
 	struct flock fl;
 	int fd;
-	pid_t pid = 1234;
+	pid_t pid = getpid();
 	pid_t pid2 = 1235;
 
 	expect_lookup(RELPATH, ino);
@@ -300,11 +305,16 @@ TEST_F(Getlk, lock_exists)
 			return (in.header.opcode == FUSE_GETLK &&
 				in.header.nodeid == ino &&
 				in.body.getlk.fh == FH &&
+				/*
+				 * Though it seems useless, libfuse expects the
+				 * owner and pid fields to be set during
+				 * FUSE_GETLK.
+				 */
 				in.body.getlk.owner == (uint32_t)pid &&
+				in.body.getlk.lk.pid == (uint64_t)pid &&
 				in.body.getlk.lk.start == 10 &&
 				in.body.getlk.lk.end == 1009 &&
-				in.body.getlk.lk.type == F_RDLCK &&
-				in.body.getlk.lk.pid == (uint64_t)pid);
+				in.body.getlk.lk.type == F_RDLCK);
 		}, Eq(true)),
 		_)
 	).WillOnce(Invoke(ReturnImmediate([=](auto in __unused, auto& out) {
@@ -319,7 +329,7 @@ TEST_F(Getlk, lock_exists)
 	ASSERT_LE(0, fd) << strerror(errno);
 	fl.l_start = 10;
 	fl.l_len = 1000;
-	fl.l_pid = pid;
+	fl.l_pid = 0;
 	fl.l_type = F_RDLCK;
 	fl.l_whence = SEEK_SET;
 	fl.l_sysid = 0;
@@ -368,7 +378,7 @@ TEST_F(Setlk, clear)
 	uint64_t ino = 42;
 	struct flock fl;
 	int fd;
-	pid_t pid = 1234;
+	pid_t pid = getpid();
 
 	expect_lookup(RELPATH, ino);
 	expect_open(ino, 0, 1);
@@ -378,7 +388,7 @@ TEST_F(Setlk, clear)
 	ASSERT_LE(0, fd) << strerror(errno);
 	fl.l_start = 10;
 	fl.l_len = 1000;
-	fl.l_pid = pid;
+	fl.l_pid = 0;
 	fl.l_type = F_UNLCK;
 	fl.l_whence = SEEK_SET;
 	fl.l_sysid = 0;
@@ -394,7 +404,7 @@ TEST_F(Setlk, set)
 	uint64_t ino = 42;
 	struct flock fl;
 	int fd;
-	pid_t pid = 1234;
+	pid_t pid = getpid();
 
 	expect_lookup(RELPATH, ino);
 	expect_open(ino, 0, 1);
@@ -404,7 +414,7 @@ TEST_F(Setlk, set)
 	ASSERT_LE(0, fd) << strerror(errno);
 	fl.l_start = 10;
 	fl.l_len = 1000;
-	fl.l_pid = pid;
+	fl.l_pid = 0;
 	fl.l_type = F_RDLCK;
 	fl.l_whence = SEEK_SET;
 	fl.l_sysid = 0;
@@ -420,7 +430,7 @@ TEST_F(Setlk, set_eof)
 	uint64_t ino = 42;
 	struct flock fl;
 	int fd;
-	pid_t pid = 1234;
+	pid_t pid = getpid();
 
 	expect_lookup(RELPATH, ino);
 	expect_open(ino, 0, 1);
@@ -430,7 +440,7 @@ TEST_F(Setlk, set_eof)
 	ASSERT_LE(0, fd) << strerror(errno);
 	fl.l_start = 10;
 	fl.l_len = 0;
-	fl.l_pid = pid;
+	fl.l_pid = 0;
 	fl.l_type = F_RDLCK;
 	fl.l_whence = SEEK_SET;
 	fl.l_sysid = 0;
@@ -446,7 +456,7 @@ TEST_F(Setlk, eagain)
 	uint64_t ino = 42;
 	struct flock fl;
 	int fd;
-	pid_t pid = 1234;
+	pid_t pid = getpid();
 
 	expect_lookup(RELPATH, ino);
 	expect_open(ino, 0, 1);
@@ -456,7 +466,7 @@ TEST_F(Setlk, eagain)
 	ASSERT_LE(0, fd) << strerror(errno);
 	fl.l_start = 10;
 	fl.l_len = 1000;
-	fl.l_pid = pid;
+	fl.l_pid = 0;
 	fl.l_type = F_RDLCK;
 	fl.l_whence = SEEK_SET;
 	fl.l_sysid = 0;
@@ -484,7 +494,7 @@ TEST_F(SetlkwFallback, local)
 	ASSERT_LE(0, fd) << strerror(errno);
 	fl.l_start = 10;
 	fl.l_len = 1000;
-	fl.l_pid = getpid();
+	fl.l_pid = 0;
 	fl.l_type = F_RDLCK;
 	fl.l_whence = SEEK_SET;
 	fl.l_sysid = 0;
@@ -504,7 +514,7 @@ TEST_F(Setlkw, set)
 	uint64_t ino = 42;
 	struct flock fl;
 	int fd;
-	pid_t pid = 1234;
+	pid_t pid = getpid();
 
 	expect_lookup(RELPATH, ino);
 	expect_open(ino, 0, 1);
@@ -514,7 +524,7 @@ TEST_F(Setlkw, set)
 	ASSERT_LE(0, fd) << strerror(errno);
 	fl.l_start = 10;
 	fl.l_len = 1000;
-	fl.l_pid = pid;
+	fl.l_pid = 0;
 	fl.l_type = F_RDLCK;
 	fl.l_whence = SEEK_SET;
 	fl.l_sysid = 0;