On Tue, May 08, 2012 at 11:29:42AM -0500, Ben Myers wrote: > On Fri, Apr 27, 2012 at 07:45:22PM +1000, Dave Chinner wrote: > > From: Dave Chinner <dchinner@xxxxxxxxxx> > > > > Often mounting small filesystem with small logs will emit a warning > > such as: > > > > XFS (vdb): Invalid block length (0x2000) for buffer > > > > during log recovery. This causes tests to randomly fail because this > > output causes the clean filesystem checks on test completion to > > think the filesystem is inconsistent. > > > > The cause of the error is simply that log recovery is asking for a > > buffer size that is larger than the log when zeroing the tail. This > > is because the buffer size is rounded up, and if the right head and > > tail conditions exist then the buffer size can be larger than the log. > > Limit the variable size xlog_get_bp() callers to requesting buffers > > smaller than the log. > > > > Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx> > > --- > > fs/xfs/xfs_log_recover.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c > > index d7abe5f..ca38690 100644 > > --- a/fs/xfs/xfs_log_recover.c > > +++ b/fs/xfs/xfs_log_recover.c > > @@ -441,6 +441,8 @@ xlog_find_verify_cycle( > > * a log sector, or we're out of luck. > > */ > > bufblks = 1 << ffs(nbblks); > > + while (bufblks > log->l_logBBsize) > > + bufblks >>= 1; > > AFAICS you don't need a loop here. The following would be sufficient to make > xlog_buf_bbcount_valid return 0. > > if (bufblks > log->l_logBBsize) > bufblks = log->l_logBBsize; Yes, I could do that, but then there is a different set of boundary conditions to test. I know that the >>=1 logic works, but I have no idea what new corner cases occur when bufblks == log->l_logBBsize. > It is a bit more obviously correct. It may be to read, but it's certainly more different from a verification point of view. Given how long and arduous the process was to find the source of the problem, I am very wary of changing logic to run in ways that are different and very difficult to actually test.... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
