Re: [PATCH 2/3] xfs: make xfs_btree_magic more generic

Darrick J. Wong
2016-12-22T19:22:17Z

On Thu, Dec 22, 2016 at 11:47:26AM -0600, Eric Sandeen wrote:
> Right now the xfs_btree_magic() define takes only a cursor;
> change this to take crc and btnum args to make it more generically
> useful, and move to a header file.
>
> This will allow xfs_btree_init_block_int callers which don't
> have a cursor to make use of the xfs_magics array, which will
> happen in the next patch.
>
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
> ---
>
> diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
> index f49fc2f..cdb952a 100644
> --- a/fs/xfs/libxfs/xfs_btree.c
> +++ b/fs/xfs/libxfs/xfs_btree.c
> @@ -50,8 +50,6 @@
> XFS_BMAP_CRC_MAGIC, XFS_IBT_CRC_MAGIC, XFS_FIBT_CRC_MAGIC,
> XFS_REFC_CRC_MAGIC }
> };
> -#define xfs_btree_magic(cur) \
> - xfs_magics[!!((cur)->bc_flags & XFS_BTREE_CRC_BLOCKS)][cur->bc_btnum]
>
> STATIC int /* error (0 or EFSCORRUPTED) */
> xfs_btree_check_lblock(
> @@ -62,10 +60,13 @@
> {
> int lblock_ok = 1; /* block passes checks */
> struct xfs_mount *mp; /* file system mount point */
> + xfs_btnum_t btnum = cur->bc_btnum;
> + int crc;
>
> mp = cur->bc_mp;
> + crc = xfs_sb_version_hascrc(&mp->m_sb);
>
> - if (xfs_sb_version_hascrc(&mp->m_sb)) {
> + if (crc) {
> lblock_ok = lblock_ok &&
> uuid_equal(&block->bb_u.l.bb_uuid,
> &mp->m_sb.sb_meta_uuid) &&
> @@ -74,7 +75,7 @@
> }
>
> lblock_ok = lblock_ok &&
> - be32_to_cpu(block->bb_magic) == xfs_btree_magic(cur) &&
> + be32_to_cpu(block->bb_magic) == xfs_btree_magic(crc, btnum) &&
> be16_to_cpu(block->bb_level) == level &&
> be16_to_cpu(block->bb_numrecs) <=
> cur->bc_ops->get_maxrecs(cur, level) &&
> @@ -110,13 +111,16 @@
> struct xfs_agf *agf; /* ag. freespace structure */
> xfs_agblock_t agflen; /* native ag. freespace length */
> int sblock_ok = 1; /* block passes checks */
> + xfs_btnum_t btnum = cur->bc_btnum;
> + int crc;
>
> mp = cur->bc_mp;
> + crc = xfs_sb_version_hascrc(&mp->m_sb);
> agbp = cur->bc_private.a.agbp;
> agf = XFS_BUF_TO_AGF(agbp);
> agflen = be32_to_cpu(agf->agf_length);
>
> - if (xfs_sb_version_hascrc(&mp->m_sb)) {
> + if (crc) {
> sblock_ok = sblock_ok &&
> uuid_equal(&block->bb_u.s.bb_uuid,
> &mp->m_sb.sb_meta_uuid) &&
> @@ -125,7 +129,7 @@
> }
>
> sblock_ok = sblock_ok &&
> - be32_to_cpu(block->bb_magic) == xfs_btree_magic(cur) &&
> + be32_to_cpu(block->bb_magic) == xfs_btree_magic(crc, btnum) &&
> be16_to_cpu(block->bb_level) == level &&
> be16_to_cpu(block->bb_numrecs) <=
> cur->bc_ops->get_maxrecs(cur, level) &&
> @@ -1142,7 +1146,9 @@ static inline size_t xfs_btree_ptr_len(struct xfs_btree_cur *cur)
> int level,
> int numrecs)
> {
> - __u64 owner;
> + __u64 owner;
> + int crc = xfs_sb_version_hascrc(&cur->bc_mp->m_sb);
> + xfs_btnum_t btnum = cur->bc_btnum;
>
> /*
> * we can pull the owner from the cursor right now as the different
> @@ -1156,7 +1162,7 @@ static inline size_t xfs_btree_ptr_len(struct xfs_btree_cur *cur)
> owner = cur->bc_private.a.agno;
>
> xfs_btree_init_block_int(cur->bc_mp, XFS_BUF_TO_BLOCK(bp), bp->b_bn,
> - xfs_btree_magic(cur), level, numrecs,
> + xfs_btree_magic(crc, btnum), level, numrecs,
> owner, cur->bc_flags);
> }
>
> diff --git a/fs/xfs/libxfs/xfs_types.h b/fs/xfs/libxfs/xfs_types.h
> index 8d74870..8ddacf4 100644
> --- a/fs/xfs/libxfs/xfs_types.h
> +++ b/fs/xfs/libxfs/xfs_types.h
> @@ -113,6 +113,8 @@
> XFS_BTNUM_INOi, XFS_BTNUM_FINOi, XFS_BTNUM_REFCi, XFS_BTNUM_MAX
> } xfs_btnum_t;
>
> +#define xfs_btree_magic(crc, btnum) xfs_magics[crc][btnum]

TBH I was expecting this to be a static inline function instead of a
macro that looks like a function. Maybe an assert to catch things like
crc=0, btnum=XFS_BTNUM_RMAP that aren't supposed to exist.

(I see that the third patch has one assert, but why not just leave it in
the helper to catch any error case?)

--D

> +
> struct xfs_name {
> const unsigned char *name;
> int len;
>
>
> --
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