locks: report l_pid as -1 for FL_FILE_PVT locks (3fd80cdd) · Commits · 戴 / test

FL_FILE_PVT locks are no longer tied to a particular pid, and are instead inheritable by child processes. Report a l_pid of '-1' for these sorts of locks since the pid is somewhat meaningless for them. This precedent comes from FreeBSD. There, POSIX and flock() locks can conflict with one another. If fcntl(F_GETLK, ...) returns a lock set with flock() then the l_pid member cannot be a process ID because the lock is not held by a process as such. Acked-by:

J. Bruce Fields <bfields@fieldses.org> Signed-off-by:

Jeff Layton <jlayton@redhat.com>

fs/locks.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1864,7 +1864,7 @@ EXPORT_SYMBOL_GPL(vfs_test_lock);

		static int posix_lock_to_flock(struct flock flock, struct file_lock fl)
		{
		flock->l_pid = fl->fl_pid;
		flock->l_pid = IS_FILE_PVT(fl) ? -1 : fl->fl_pid;
		#if BITS_PER_LONG == 32
		/*
		* Make sure we can represent the posix lock via
		@@ -1886,7 +1886,7 @@ static int posix_lock_to_flock(struct flock flock, struct file_lock fl)
		#if BITS_PER_LONG == 32
		static void posix_lock_to_flock64(struct flock64 flock, struct file_lock fl)
		{
		flock->l_pid = fl->fl_pid;
		flock->l_pid = IS_FILE_PVT(fl) ? -1 : fl->fl_pid;
		flock->l_start = fl->fl_start;
		flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
		fl->fl_end - fl->fl_start + 1;

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