Commit 129a84de authored May 10, 2007 by J. Bruce Fields Committed by Linus Torvalds May 10, 2007

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: "J. Bruce Fields" <bfields@citi.umich.edu>
Acked-by: Doug Chapman <doug.chapman@hp.com>
Signed-off-by: Linus 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;
		}

Admin message