Re: [PATCH v2 1/3] xfs: log the inode on directory sf to block format change

[Christoph Hellwig <hch@infradead.org>]

On Mon, Oct 07, 2019 at 09:19:36AM -0400, Brian Foster wrote:
> When a directory changes from shortform (sf) to block format, the sf
> format is copied to a temporary buffer, the inode format is modified
> and the updated format filled with the dentries from the temporary
> buffer. If the inode format is modified and attempt to grow the
> inode fails (due to I/O error, for example), it is possible to
> return an error while leaving the directory in an inconsistent state
> and with an otherwise clean transaction. This results in corruption
> of the associated directory and leads to xfs_dabuf_map() errors as
> subsequent lookups cannot accurately determine the format of the
> directory. This problem is reproduced occasionally by generic/475.
> 
> The fundamental problem is that xfs_dir2_sf_to_block() changes the
> on-disk inode format without logging the inode. The inode is
> eventually logged by the bmapi layer in the common case, but error
> checking introduces the possibility of failing the high level
> request before this happens.
> 
> Update both of the dir2 and attr callers of
> xfs_bmap_local_to_extents_empty() to log the inode core as
> consistent with the bmap local to extent format change codepath.
> This ensures that any subsequent errors after the format has changed
> cause the transaction to abort.
> 
> Signed-off-by: Brian Foster <bfoster@redhat.com>

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>