Re: [PATCH v18 07/15] xfs: add XFS_BMAPI_UNWRITTEN to unmap unwritten extents in __xfs_bunmapi()

[Christoph Hellwig <hch@infradead.org>]

On Tue, Nov 03, 2026 at 03:31:15PM +0100, Andrey Albershteyn wrote:
> On 2026-11-03 01:41:19, Christoph Hellwig wrote:
> > On Mon, Nov 02, 2026 at 03:41:37PM +0100, Andrey Albershteyn wrote:
> > > The __xfs_bunmapi() is used to remove all extents past EOF. Add
> > > XFS_BMAPI_UNWRITTEN to remove only unwritten extents, while leaving
> > > written ones in place. This will be used in following patch to clean up
> > > unwritten extents on fsverity inodes.
> > 
> > As discussed before, we either need to fix the Sashiko complains (which
> > could get really annoying), or disallow fsverity on RT files with
> > rt extent size > 1.  And probably also add a soft assert about this
> > to __xfs_bunmapi itself to make the limitations clear.
> > 
> > Otherwise this looks good.
> > 
> 
> Yes, I added the check in "[PATCH v18 09/15] xfs: add fs-verity
> support" [1] in xfs_fsverity_begin_enable()
> 
> +	/*
> +	 * fs-verity stores the Merkle tree past EOF in units of the filesystem
> +	 * block size, so it cannot support realtime files whose allocation unit
> +	 * (extent size) is larger than the block size.
> +	 */
> +	if (xfs_inode_has_bigrtalloc(ip))

Please also add a similar check/comment in __xfs_bunampi for the
XFS_BMAPI_UNWRITTEN case as a safeguard and documentation of the
limitations.