On Fri, Mar 06, 2020 at 07:52:15AM -0700, Christoph Hellwig wrote:
> struct xfs_agfl is a header in front of the AGFL entries that exists
> for CRC enabled file systems. For not CRC enabled file systems the AGFL
> is simply a list of agbno. Make the CRC case similar to that by just
> using the list behind the new header. This indirectly solves a problem
> with modern gcc versions that warn about taking addresses of packed
> structures (and we have to pack the AGFL given that gcc rounds up
> structure sizes). Also replace the helper macro to get from a buffer
> with an inline function in xfs_alloc.h to make the code easier to
> read.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> Reviewed-by: Eric Sandeen <sandeen@xxxxxxxxxx>
> ---
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
> fs/xfs/libxfs/xfs_ag.c | 2 +-
> fs/xfs/libxfs/xfs_alloc.c | 11 ++++++-----
> fs/xfs/libxfs/xfs_alloc.h | 9 +++++++++
> fs/xfs/libxfs/xfs_format.h | 6 ------
> fs/xfs/scrub/agheader_repair.c | 2 +-
> 5 files changed, 17 insertions(+), 13 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c
> index 08d6beb54f8c..831bdd035900 100644
> --- a/fs/xfs/libxfs/xfs_ag.c
> +++ b/fs/xfs/libxfs/xfs_ag.c
> @@ -301,7 +301,7 @@ xfs_agflblock_init(
> uuid_copy(&agfl->agfl_uuid, &mp->m_sb.sb_meta_uuid);
> }
>
> - agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, bp);
> + agfl_bno = xfs_buf_to_agfl_bno(bp);
> for (bucket = 0; bucket < xfs_agfl_size(mp); bucket++)
> agfl_bno[bucket] = cpu_to_be32(NULLAGBLOCK);
> }
> diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
> index 183dc2587092..f668e62acc56 100644
> --- a/fs/xfs/libxfs/xfs_alloc.c
> +++ b/fs/xfs/libxfs/xfs_alloc.c
> @@ -589,6 +589,7 @@ xfs_agfl_verify(
> {
> struct xfs_mount *mp = bp->b_mount;
> struct xfs_agfl *agfl = XFS_BUF_TO_AGFL(bp);
> + __be32 *agfl_bno = xfs_buf_to_agfl_bno(bp);
> int i;
>
> /*
> @@ -614,8 +615,8 @@ xfs_agfl_verify(
> return __this_address;
>
> for (i = 0; i < xfs_agfl_size(mp); i++) {
> - if (be32_to_cpu(agfl->agfl_bno[i]) != NULLAGBLOCK &&
> - be32_to_cpu(agfl->agfl_bno[i]) >= mp->m_sb.sb_agblocks)
> + if (be32_to_cpu(agfl_bno[i]) != NULLAGBLOCK &&
> + be32_to_cpu(agfl_bno[i]) >= mp->m_sb.sb_agblocks)
> return __this_address;
> }
>
> @@ -2684,7 +2685,7 @@ xfs_alloc_get_freelist(
> /*
> * Get the block number and update the data structures.
> */
> - agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, agflbp);
> + agfl_bno = xfs_buf_to_agfl_bno(agflbp);
> bno = be32_to_cpu(agfl_bno[be32_to_cpu(agf->agf_flfirst)]);
> be32_add_cpu(&agf->agf_flfirst, 1);
> xfs_trans_brelse(tp, agflbp);
> @@ -2820,7 +2821,7 @@ xfs_alloc_put_freelist(
>
> ASSERT(be32_to_cpu(agf->agf_flcount) <= xfs_agfl_size(mp));
>
> - agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, agflbp);
> + agfl_bno = xfs_buf_to_agfl_bno(agflbp);
> blockp = &agfl_bno[be32_to_cpu(agf->agf_fllast)];
> *blockp = cpu_to_be32(bno);
> startoff = (char *)blockp - (char *)agflbp->b_addr;
> @@ -3424,7 +3425,7 @@ xfs_agfl_walk(
> unsigned int i;
> int error;
>
> - agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, agflbp);
> + agfl_bno = xfs_buf_to_agfl_bno(agflbp);
> i = be32_to_cpu(agf->agf_flfirst);
>
> /* Nothing to walk in an empty AGFL. */
> diff --git a/fs/xfs/libxfs/xfs_alloc.h b/fs/xfs/libxfs/xfs_alloc.h
> index 7380fbe4a3ff..a851bf77f17b 100644
> --- a/fs/xfs/libxfs/xfs_alloc.h
> +++ b/fs/xfs/libxfs/xfs_alloc.h
> @@ -236,4 +236,13 @@ typedef int (*xfs_agfl_walk_fn)(struct xfs_mount *mp, xfs_agblock_t bno,
> int xfs_agfl_walk(struct xfs_mount *mp, struct xfs_agf *agf,
> struct xfs_buf *agflbp, xfs_agfl_walk_fn walk_fn, void *priv);
>
> +static inline __be32 *
> +xfs_buf_to_agfl_bno(
> + struct xfs_buf *bp)
> +{
> + if (xfs_sb_version_hascrc(&bp->b_mount->m_sb))
> + return bp->b_addr + sizeof(struct xfs_agfl);
> + return bp->b_addr;
> +}
> +
> #endif /* __XFS_ALLOC_H__ */
> diff --git a/fs/xfs/libxfs/xfs_format.h b/fs/xfs/libxfs/xfs_format.h
> index 77e9fa385980..8c7aea7795da 100644
> --- a/fs/xfs/libxfs/xfs_format.h
> +++ b/fs/xfs/libxfs/xfs_format.h
> @@ -785,18 +785,12 @@ typedef struct xfs_agi {
> #define XFS_AGFL_BLOCK(mp) XFS_HDR_BLOCK(mp, XFS_AGFL_DADDR(mp))
> #define XFS_BUF_TO_AGFL(bp) ((xfs_agfl_t *)((bp)->b_addr))
>
> -#define XFS_BUF_TO_AGFL_BNO(mp, bp) \
> - (xfs_sb_version_hascrc(&((mp)->m_sb)) ? \
> - &(XFS_BUF_TO_AGFL(bp)->agfl_bno[0]) : \
> - (__be32 *)(bp)->b_addr)
> -
> typedef struct xfs_agfl {
> __be32 agfl_magicnum;
> __be32 agfl_seqno;
> uuid_t agfl_uuid;
> __be64 agfl_lsn;
> __be32 agfl_crc;
> - __be32 agfl_bno[]; /* actually xfs_agfl_size(mp) */
> } __attribute__((packed)) xfs_agfl_t;
>
> #define XFS_AGFL_CRC_OFF offsetof(struct xfs_agfl, agfl_crc)
> diff --git a/fs/xfs/scrub/agheader_repair.c b/fs/xfs/scrub/agheader_repair.c
> index d5e6db9af434..68ee1ce1ae36 100644
> --- a/fs/xfs/scrub/agheader_repair.c
> +++ b/fs/xfs/scrub/agheader_repair.c
> @@ -602,7 +602,7 @@ xrep_agfl_init_header(
> * step.
> */
> fl_off = 0;
> - agfl_bno = XFS_BUF_TO_AGFL_BNO(mp, agfl_bp);
> + agfl_bno = xfs_buf_to_agfl_bno(agfl_bp);
> for_each_xfs_bitmap_extent(br, n, agfl_extents) {
> agbno = XFS_FSB_TO_AGBNO(mp, br->start);
>
> --
> 2.24.1
>
