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Commit 129a84de authored by J. Bruce Fields's avatar J. Bruce Fields Committed by Linus Torvalds
Browse files

locks: fix F_GETLK regression (failure to find conflicts) 



In 9d6a8c5c we changed posix_test_lock
to modify its single file_lock argument instead of taking separate input
and output arguments.  This makes it no longer safe to set the output
lock's fl_type to F_UNLCK before looking for a conflict, since that
means searching for a conflict against a lock with type F_UNLCK.

This fixes a regression which causes F_GETLK to incorrectly report no
conflict on most filesystems (including any filesystem that doesn't do
its own locking).

Also fix posix_lock_to_flock() to copy the lock type.  This isn't
strictly necessary, since the caller already does this; but it seems
less likely to cause confusion in the future.

Thanks to Doug Chapman for the bug report.

Signed-off-by: default avatar"J. Bruce Fields" <bfields@citi.umich.edu>
Acked-by: default avatarDoug Chapman <doug.chapman@hp.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a9deecba

fs/locks.c

+3 −2
Original line number Diff line number Diff line
@@ -669,7 +669,6 @@ posix_test_lock(struct file *filp, struct file_lock *fl) 
{

	struct file_lock *cfl;



	fl->fl_type = F_UNLCK;

	lock_kernel();

	for (cfl = filp->f_path.dentry->d_inode->i_flock; cfl; cfl = cfl->fl_next) {

		if (!IS_POSIX(cfl))
@@ -681,7 +680,8 @@ posix_test_lock(struct file *filp, struct file_lock *fl) 
		__locks_copy_lock(fl, cfl);

		unlock_kernel();

		return 1;

	}

	} else

		fl->fl_type = F_UNLCK;

	unlock_kernel();

	return 0;

}
@@ -1632,6 +1632,7 @@ static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl) 
	flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :

		fl->fl_end - fl->fl_start + 1;

	flock->l_whence = 0;

	flock->l_type = fl->fl_type;

	return 0;

}