Re: [PATCH 2/2] xfs: validate allocated inode number

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Tue, Apr 17, 2018 at 04:39:16PM +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> When we have corrupted free inode btrees, we can attempt to
> allocate inodes that we know are already allocated. Catch allocation
> of these inodes and report corruption as early as possible to
> prevent corruption propagation or deadlocks.
> 
> Signed-Off-By: Dave Chinner <dchinner@redhat.com>

Looks ok, will test...
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
>  fs/xfs/xfs_inode.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index 7b764f746ff2..12e6c1aec386 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -790,6 +790,19 @@ xfs_ialloc(
>  	}
>  	ASSERT(*ialloc_context == NULL);
>  
> +	/*
> +	 * Protect against obviously corrupt allocation btree records. Later
> +	 * xfs_iget checks will catch re-allocation of other active in-memory
> +	 * and on-disk inodes. If we don't catch reallocating the parent inode
> +	 * here we will deadlock in xfs_iget() so we have to do these checks
> +	 * first.
> +	 */
> +	if ((pip && ino == pip->i_ino) ||
> +	    !xfs_verify_dir_ino(mp, ino)) {
> +		xfs_alert(mp, "Allocated a known in-use inode 0x%llx!", ino);
> +		return -EFSCORRUPTED;
> +	}
> +
>  	/*
>  	 * Get the in-core inode with the lock held exclusively.
>  	 * This is because we're setting fields here we need
> -- 
> 2.16.1
> 
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