Re: [PATCH 028/119] xfs: define the on-disk rmap btree format

[Brian Foster <bfoster@redhat.com>]

On Thu, Jun 16, 2016 at 06:20:52PM -0700, Darrick J. Wong wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> Now we have all the surrounding call infrastructure in place, we can
> start filling out the rmap btree implementation. Start with the
> on-disk btree format; add everything needed to read, write and
> manipulate rmap btree blocks. This prepares the way for adding the
> btree operations implementation.
> 
> [darrick: record owner and offset info in rmap btree]
> [darrick: fork, bmbt and unwritten state in rmap btree]
> [darrick: flags are a separate field in xfs_rmap_irec]
> [darrick: calculate maxlevels separately]
> [darrick: move the 'unwritten' bit into unused parts of rm_offset]
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> Reviewed-by: Dave Chinner <dchinner@redhat.com>
> Signed-off-by: Dave Chinner <david@fromorbit.com>
> ---
>  fs/xfs/Makefile                |    1 
>  fs/xfs/libxfs/xfs_btree.c      |    3 +
>  fs/xfs/libxfs/xfs_btree.h      |   18 ++--
>  fs/xfs/libxfs/xfs_format.h     |  140 +++++++++++++++++++++++++++++++
>  fs/xfs/libxfs/xfs_rmap_btree.c |  180 ++++++++++++++++++++++++++++++++++++++++
>  fs/xfs/libxfs/xfs_rmap_btree.h |   32 +++++++
>  fs/xfs/libxfs/xfs_sb.c         |    6 +
>  fs/xfs/libxfs/xfs_shared.h     |    2 
>  fs/xfs/xfs_mount.c             |    2 
>  fs/xfs/xfs_mount.h             |    3 +
>  fs/xfs/xfs_ondisk.h            |    3 +
>  fs/xfs/xfs_trace.h             |    2 
>  12 files changed, 384 insertions(+), 8 deletions(-)
>  create mode 100644 fs/xfs/libxfs/xfs_rmap_btree.c
> 
> 
...
> diff --git a/fs/xfs/libxfs/xfs_rmap_btree.c b/fs/xfs/libxfs/xfs_rmap_btree.c
> new file mode 100644
> index 0000000..7a35c78
> --- /dev/null
> +++ b/fs/xfs/libxfs/xfs_rmap_btree.c
> @@ -0,0 +1,180 @@
...
> +static bool
> +xfs_rmapbt_verify(
> +	struct xfs_buf		*bp)
> +{
> +	struct xfs_mount	*mp = bp->b_target->bt_mount;
> +	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
> +	struct xfs_perag	*pag = bp->b_pag;
> +	unsigned int		level;
> +
> +	/*
> +	 * magic number and level verification
> +	 *
> +	 * During growfs operations, we can't verify the exact level or owner as
> +	 * the perag is not fully initialised and hence not attached to the
> +	 * buffer.  In this case, check against the maximum tree depth.
> +	 *
> +	 * Similarly, during log recovery we will have a perag structure
> +	 * attached, but the agf information will not yet have been initialised
> +	 * from the on disk AGF. Again, we can only check against maximum limits
> +	 * in this case.
> +	 */
> +	if (block->bb_magic != cpu_to_be32(XFS_RMAP_CRC_MAGIC))
> +		return false;
> +
> +	if (!xfs_sb_version_hasrmapbt(&mp->m_sb))
> +		return false;
> +	if (!xfs_btree_sblock_v5hdr_verify(bp))
> +		return false;
> +
> +	level = be16_to_cpu(block->bb_level);
> +	if (pag && pag->pagf_init) {
> +		if (level >= pag->pagf_levels[XFS_BTNUM_RMAPi])
> +			return false;
> +	} else if (level >= mp->m_rmap_maxlevels)
> +		return false;

It looks like the above (level >= mp->m_rmap_maxlevels) check could be
independent (rather than an 'else). Otherwise looks good:

Reviewed-by: Brian Foster <bfoster@redhat.com>

> +
> +	return xfs_btree_sblock_verify(bp, mp->m_rmap_mxr[level != 0]);
> +}
> +
> +static void
> +xfs_rmapbt_read_verify(
> +	struct xfs_buf	*bp)
> +{
> +	if (!xfs_btree_sblock_verify_crc(bp))
> +		xfs_buf_ioerror(bp, -EFSBADCRC);
> +	else if (!xfs_rmapbt_verify(bp))
> +		xfs_buf_ioerror(bp, -EFSCORRUPTED);
> +
> +	if (bp->b_error) {
> +		trace_xfs_btree_corrupt(bp, _RET_IP_);
> +		xfs_verifier_error(bp);
> +	}
> +}
> +
> +static void
> +xfs_rmapbt_write_verify(
> +	struct xfs_buf	*bp)
> +{
> +	if (!xfs_rmapbt_verify(bp)) {
> +		trace_xfs_btree_corrupt(bp, _RET_IP_);
> +		xfs_buf_ioerror(bp, -EFSCORRUPTED);
> +		xfs_verifier_error(bp);
> +		return;
> +	}
> +	xfs_btree_sblock_calc_crc(bp);
> +
> +}
> +
> +const struct xfs_buf_ops xfs_rmapbt_buf_ops = {
> +	.name			= "xfs_rmapbt",
> +	.verify_read		= xfs_rmapbt_read_verify,
> +	.verify_write		= xfs_rmapbt_write_verify,
> +};
> +
> +static const struct xfs_btree_ops xfs_rmapbt_ops = {
> +	.rec_len		= sizeof(struct xfs_rmap_rec),
> +	.key_len		= sizeof(struct xfs_rmap_key),
> +
> +	.dup_cursor		= xfs_rmapbt_dup_cursor,
> +	.buf_ops		= &xfs_rmapbt_buf_ops,
> +};
> +
> +/*
> + * Allocate a new allocation btree cursor.
> + */
> +struct xfs_btree_cur *
> +xfs_rmapbt_init_cursor(
> +	struct xfs_mount	*mp,
> +	struct xfs_trans	*tp,
> +	struct xfs_buf		*agbp,
> +	xfs_agnumber_t		agno)
> +{
> +	struct xfs_agf		*agf = XFS_BUF_TO_AGF(agbp);
> +	struct xfs_btree_cur	*cur;
> +
> +	cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_NOFS);
> +	cur->bc_tp = tp;
> +	cur->bc_mp = mp;
> +	cur->bc_btnum = XFS_BTNUM_RMAP;
> +	cur->bc_flags = XFS_BTREE_CRC_BLOCKS;
> +	cur->bc_blocklog = mp->m_sb.sb_blocklog;
> +	cur->bc_ops = &xfs_rmapbt_ops;
> +	cur->bc_nlevels = be32_to_cpu(agf->agf_levels[XFS_BTNUM_RMAP]);
> +
> +	cur->bc_private.a.agbp = agbp;
> +	cur->bc_private.a.agno = agno;
> +
> +	return cur;
> +}
> +
> +/*
> + * Calculate number of records in an rmap btree block.
> + */
> +int
> +xfs_rmapbt_maxrecs(
> +	struct xfs_mount	*mp,
> +	int			blocklen,
> +	int			leaf)
> +{
> +	blocklen -= XFS_RMAP_BLOCK_LEN;
> +
> +	if (leaf)
> +		return blocklen / sizeof(struct xfs_rmap_rec);
> +	return blocklen /
> +		(sizeof(struct xfs_rmap_key) + sizeof(xfs_rmap_ptr_t));
> +}
> +
> +/* Compute the maximum height of an rmap btree. */
> +void
> +xfs_rmapbt_compute_maxlevels(
> +	struct xfs_mount		*mp)
> +{
> +	mp->m_rmap_maxlevels = xfs_btree_compute_maxlevels(mp,
> +			mp->m_rmap_mnr, mp->m_sb.sb_agblocks);
> +}
> diff --git a/fs/xfs/libxfs/xfs_rmap_btree.h b/fs/xfs/libxfs/xfs_rmap_btree.h
> index a3b8f90..462767f 100644
> --- a/fs/xfs/libxfs/xfs_rmap_btree.h
> +++ b/fs/xfs/libxfs/xfs_rmap_btree.h
> @@ -19,6 +19,38 @@
>  #define	__XFS_RMAP_BTREE_H__
>  
>  struct xfs_buf;
> +struct xfs_btree_cur;
> +struct xfs_mount;
> +
> +/* rmaps only exist on crc enabled filesystems */
> +#define XFS_RMAP_BLOCK_LEN	XFS_BTREE_SBLOCK_CRC_LEN
> +
> +/*
> + * Record, key, and pointer address macros for btree blocks.
> + *
> + * (note that some of these may appear unused, but they are used in userspace)
> + */
> +#define XFS_RMAP_REC_ADDR(block, index) \
> +	((struct xfs_rmap_rec *) \
> +		((char *)(block) + XFS_RMAP_BLOCK_LEN + \
> +		 (((index) - 1) * sizeof(struct xfs_rmap_rec))))
> +
> +#define XFS_RMAP_KEY_ADDR(block, index) \
> +	((struct xfs_rmap_key *) \
> +		((char *)(block) + XFS_RMAP_BLOCK_LEN + \
> +		 ((index) - 1) * sizeof(struct xfs_rmap_key)))
> +
> +#define XFS_RMAP_PTR_ADDR(block, index, maxrecs) \
> +	((xfs_rmap_ptr_t *) \
> +		((char *)(block) + XFS_RMAP_BLOCK_LEN + \
> +		 (maxrecs) * sizeof(struct xfs_rmap_key) + \
> +		 ((index) - 1) * sizeof(xfs_rmap_ptr_t)))
> +
> +struct xfs_btree_cur *xfs_rmapbt_init_cursor(struct xfs_mount *mp,
> +				struct xfs_trans *tp, struct xfs_buf *bp,
> +				xfs_agnumber_t agno);
> +int xfs_rmapbt_maxrecs(struct xfs_mount *mp, int blocklen, int leaf);
> +extern void xfs_rmapbt_compute_maxlevels(struct xfs_mount *mp);
>  
>  int xfs_rmap_alloc(struct xfs_trans *tp, struct xfs_buf *agbp,
>  		   xfs_agnumber_t agno, xfs_agblock_t bno, xfs_extlen_t len,
> diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
> index a544686..f86226b 100644
> --- a/fs/xfs/libxfs/xfs_sb.c
> +++ b/fs/xfs/libxfs/xfs_sb.c
> @@ -37,6 +37,7 @@
>  #include "xfs_alloc_btree.h"
>  #include "xfs_ialloc_btree.h"
>  #include "xfs_log.h"
> +#include "xfs_rmap_btree.h"
>  
>  /*
>   * Physical superblock buffer manipulations. Shared with libxfs in userspace.
> @@ -734,6 +735,11 @@ xfs_sb_mount_common(
>  	mp->m_bmap_dmnr[0] = mp->m_bmap_dmxr[0] / 2;
>  	mp->m_bmap_dmnr[1] = mp->m_bmap_dmxr[1] / 2;
>  
> +	mp->m_rmap_mxr[0] = xfs_rmapbt_maxrecs(mp, sbp->sb_blocksize, 1);
> +	mp->m_rmap_mxr[1] = xfs_rmapbt_maxrecs(mp, sbp->sb_blocksize, 0);
> +	mp->m_rmap_mnr[0] = mp->m_rmap_mxr[0] / 2;
> +	mp->m_rmap_mnr[1] = mp->m_rmap_mxr[1] / 2;
> +
>  	mp->m_bsize = XFS_FSB_TO_BB(mp, 1);
>  	mp->m_ialloc_inos = (int)MAX((__uint16_t)XFS_INODES_PER_CHUNK,
>  					sbp->sb_inopblock);
> diff --git a/fs/xfs/libxfs/xfs_shared.h b/fs/xfs/libxfs/xfs_shared.h
> index 16002b5..0c5b30b 100644
> --- a/fs/xfs/libxfs/xfs_shared.h
> +++ b/fs/xfs/libxfs/xfs_shared.h
> @@ -38,6 +38,7 @@ extern const struct xfs_buf_ops xfs_agi_buf_ops;
>  extern const struct xfs_buf_ops xfs_agf_buf_ops;
>  extern const struct xfs_buf_ops xfs_agfl_buf_ops;
>  extern const struct xfs_buf_ops xfs_allocbt_buf_ops;
> +extern const struct xfs_buf_ops xfs_rmapbt_buf_ops;
>  extern const struct xfs_buf_ops xfs_attr3_leaf_buf_ops;
>  extern const struct xfs_buf_ops xfs_attr3_rmt_buf_ops;
>  extern const struct xfs_buf_ops xfs_bmbt_buf_ops;
> @@ -116,6 +117,7 @@ int	xfs_log_calc_minimum_size(struct xfs_mount *);
>  #define	XFS_INO_BTREE_REF	3
>  #define	XFS_ALLOC_BTREE_REF	2
>  #define	XFS_BMAP_BTREE_REF	2
> +#define	XFS_RMAP_BTREE_REF	2
>  #define	XFS_DIR_BTREE_REF	2
>  #define	XFS_INO_REF		2
>  #define	XFS_ATTR_BTREE_REF	1
> diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
> index b4153f0..8af1c88 100644
> --- a/fs/xfs/xfs_mount.c
> +++ b/fs/xfs/xfs_mount.c
> @@ -42,6 +42,7 @@
>  #include "xfs_trace.h"
>  #include "xfs_icache.h"
>  #include "xfs_sysfs.h"
> +#include "xfs_rmap_btree.h"
>  
>  
>  static DEFINE_MUTEX(xfs_uuid_table_mutex);
> @@ -680,6 +681,7 @@ xfs_mountfs(
>  	xfs_bmap_compute_maxlevels(mp, XFS_DATA_FORK);
>  	xfs_bmap_compute_maxlevels(mp, XFS_ATTR_FORK);
>  	xfs_ialloc_compute_maxlevels(mp);
> +	xfs_rmapbt_compute_maxlevels(mp);
>  
>  	xfs_set_maxicount(mp);
>  
> diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
> index 0537b1f..0ed0f29 100644
> --- a/fs/xfs/xfs_mount.h
> +++ b/fs/xfs/xfs_mount.h
> @@ -116,9 +116,12 @@ typedef struct xfs_mount {
>  	uint			m_bmap_dmnr[2];	/* min bmap btree records */
>  	uint			m_inobt_mxr[2];	/* max inobt btree records */
>  	uint			m_inobt_mnr[2];	/* min inobt btree records */
> +	uint			m_rmap_mxr[2];	/* max rmap btree records */
> +	uint			m_rmap_mnr[2];	/* min rmap btree records */
>  	uint			m_ag_maxlevels;	/* XFS_AG_MAXLEVELS */
>  	uint			m_bm_maxlevels[2]; /* XFS_BM_MAXLEVELS */
>  	uint			m_in_maxlevels;	/* max inobt btree levels. */
> +	uint			m_rmap_maxlevels; /* max rmap btree levels */
>  	xfs_extlen_t		m_ag_prealloc_blocks; /* reserved ag blocks */
>  	struct radix_tree_root	m_perag_tree;	/* per-ag accounting info */
>  	spinlock_t		m_perag_lock;	/* lock for m_perag_tree */
> diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
> index 0272301..48d544f 100644
> --- a/fs/xfs/xfs_ondisk.h
> +++ b/fs/xfs/xfs_ondisk.h
> @@ -47,11 +47,14 @@ xfs_check_ondisk_structs(void)
>  	XFS_CHECK_STRUCT_SIZE(struct xfs_dsymlink_hdr,		56);
>  	XFS_CHECK_STRUCT_SIZE(struct xfs_inobt_key,		4);
>  	XFS_CHECK_STRUCT_SIZE(struct xfs_inobt_rec,		16);
> +	XFS_CHECK_STRUCT_SIZE(struct xfs_rmap_key,		20);
> +	XFS_CHECK_STRUCT_SIZE(struct xfs_rmap_rec,		24);
>  	XFS_CHECK_STRUCT_SIZE(struct xfs_timestamp,		8);
>  	XFS_CHECK_STRUCT_SIZE(xfs_alloc_key_t,			8);
>  	XFS_CHECK_STRUCT_SIZE(xfs_alloc_ptr_t,			4);
>  	XFS_CHECK_STRUCT_SIZE(xfs_alloc_rec_t,			8);
>  	XFS_CHECK_STRUCT_SIZE(xfs_inobt_ptr_t,			4);
> +	XFS_CHECK_STRUCT_SIZE(xfs_rmap_ptr_t,			4);
>  
>  	/* dir/attr trees */
>  	XFS_CHECK_STRUCT_SIZE(struct xfs_attr3_leaf_hdr,	80);
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
> index 4872fbd..b4ee9c8 100644
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -2444,6 +2444,8 @@ DECLARE_EVENT_CLASS(xfs_rmap_class,
>  		__entry->owner = oinfo->oi_owner;
>  		__entry->offset = oinfo->oi_offset;
>  		__entry->flags = oinfo->oi_flags;
> +		if (unwritten)
> +			__entry->flags |= XFS_RMAP_UNWRITTEN;
>  	),
>  	TP_printk("dev %d:%d agno %u agbno %u len %u owner %lld offset %llu flags 0x%lx",
>  		  MAJOR(__entry->dev), MINOR(__entry->dev),
> 
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