Re: [PATCH 2/2] tests/xfs: test for post umount readahead completion panic

[Dave Chinner <david@fromorbit.com>]

On Thu, Jun 30, 2016 at 08:49:34AM -0400, Brian Foster wrote:
> XFS has a bug where directory readahead completions can occur after
> unmount. This can lead to a crash or panic because metadata read
> verification attempts to access core XFS data structures (e.g., the log)
> after they have been freed and certain pointers have been reset.
> 
> Add a test that triggers directory readahead, delays the readahead I/O
> and immediately unmounts the filesystem. This test is part of the
> dangerous group as it will cause kernels affected by the bug to crash.
.....
> +
> +# create a directory large enough for extent format
> +mkdir $SCRATCH_MNT/dir
> +for i in $(seq 0 999); do
> +	touch $SCRATCH_MNT/dir/$i
> +done

minor quibble - what's an "extent format" directory? I think you
mean a directory inode whose data fork is in extent or btree format,
not inline. i.e. not a short-form directory, but rather a block,
leaf or node format directory.

Yeah, I'm being pedantic, but we should use the correct terminology
so when someone reads it in 5 years time....

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com