Re: [PATCH 2/3] xfs: failed delalloc conversion results in bad extent lists

Christoph Hellwig
2023-02-14T08:13:41Z

On Tue, Feb 14, 2023 at 04:51:13PM +1100, Dave Chinner wrote:
> index 958e4bb2e51e..fb718a5825d5 100644
> --- a/fs/xfs/libxfs/xfs_bmap.c
> +++ b/fs/xfs/libxfs/xfs_bmap.c
> @@ -4553,8 +4553,12 @@ xfs_bmapi_convert_delalloc(
> * should only happen for the COW fork, where another thread
> * might have moved the extent to the data fork in the meantime.
> */
> - WARN_ON_ONCE(whichfork != XFS_COW_FORK);
> - error = -EAGAIN;
> + if (whichfork != XFS_COW_FORK) {
> + xfs_bmap_mark_sick(ip, whichfork);
> + error = -EFSCORRUPTED;
> + } else {
> + error = -EAGAIN;
> + }

The comment above should probably be expanded a bit on what this means
for a non-cow fork extent and how we'll handle it later.

> + if (error) {
> + if ((error == -EFSCORRUPTED) || (error == -EFSBADCRC))

Nit: no need for the inner braces.

>
> + /*
> + * If the inode is sick, then it might have delalloc extents
> + * within EOF that we were unable to convert. We have to punch
> + * them out here to release the reservation as there is no
> + * longer any data to write back into the delalloc range now.
> + */
> + if (!xfs_inode_is_healthy(ip))
> + xfs_bmap_punch_delalloc_range(ip, 0,
> + i_size_read(VFS_I(ip)));

Is i_size_read the right check here? The delalloc extent could extend
past i_size if i_size is not block aligned. Can't we just simply pass
(xfs_off_t)-1 here?