On Thu, Oct 22, 2020 at 11:46:49AM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> Make sure that we actually initialize xefi_discard when we're scheduling
> a deferred free of an AGFL block. This was (eventually) found by the
> UBSAN while I was banging on realtime rmap problems, but it exists in
> the upstream codebase. While we're at it, rearrange the structure to
> reduce the struct size from 64 to 56 bytes.
>
> Fixes: fcb762f5de2e ("xfs: add bmapi nodiscard flag")
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
> fs/xfs/libxfs/xfs_alloc.c | 1 +
> fs/xfs/libxfs/xfs_bmap.h | 2 +-
> 2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
> index 852b536551b5..15640015be9d 100644
> --- a/fs/xfs/libxfs/xfs_alloc.c
> +++ b/fs/xfs/libxfs/xfs_alloc.c
> @@ -2467,6 +2467,7 @@ xfs_defer_agfl_block(
> new->xefi_startblock = XFS_AGB_TO_FSB(mp, agno, agbno);
> new->xefi_blockcount = 1;
> new->xefi_oinfo = *oinfo;
> + new->xefi_skip_discard = false;
>
> trace_xfs_agfl_free_defer(mp, agno, 0, agbno, 1);
>
> diff --git a/fs/xfs/libxfs/xfs_bmap.h b/fs/xfs/libxfs/xfs_bmap.h
> index e1bd484e5548..6747e97a7949 100644
> --- a/fs/xfs/libxfs/xfs_bmap.h
> +++ b/fs/xfs/libxfs/xfs_bmap.h
> @@ -52,9 +52,9 @@ struct xfs_extent_free_item
> {
> xfs_fsblock_t xefi_startblock;/* starting fs block number */
> xfs_extlen_t xefi_blockcount;/* number of blocks in extent */
> + bool xefi_skip_discard;
> struct list_head xefi_list;
> struct xfs_owner_info xefi_oinfo; /* extent owner */
> - bool xefi_skip_discard;
> };
>
> #define XFS_BMAP_MAX_NMAP 4
>
