[XFS] implement generic xfs_btree_update

From: Dave Chinner <dgc@sgi.com>

The most complicated part here is the lastrec tracking for the alloc
btree. Most logic is in the update_lastrec method which has to do some
hopefully good enough dirty magic to maintain it.

[hch: split out from bigger patch and a rework of the lastrec

logic]

SGI-PV: 985583

SGI-Modid: xfs-linux-melb:xfs-kern:32194a

Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Bill O'Donnell <billodo@sgi.com>
Signed-off-by: David Chinner <david@fromorbit.com>

fs/xfs/xfs_alloc.c

@@ -136,6 +136,23 @@ xfs_alloc_lookup_le(
 	return xfs_btree_lookup(cur, XFS_LOOKUP_LE, stat);
 }
 
+/*
+ * Update the record referred to by cur to the value given
+ * by [bno, len].
+ * This either works (return 0) or gets an EFSCORRUPTED error.
+ */
+STATIC int				/* error */
+xfs_alloc_update(
+	struct xfs_btree_cur	*cur,	/* btree cursor */
+	xfs_agblock_t		bno,	/* starting block of extent */
+	xfs_extlen_t		len)	/* length of extent */
+{
+	union xfs_btree_rec	rec;
+
+	rec.alloc.ar_startblock = cpu_to_be32(bno);
+	rec.alloc.ar_blockcount = cpu_to_be32(len);
+	return xfs_btree_update(cur, &rec);
+}
 
 /*
  * Compute aligned version of the found extent.

fs/xfs/xfs_alloc_btree.c

@@ -1661,83 +1661,50 @@ xfs_alloc_insert(
 	return 0;
 }
 
+STATIC struct xfs_btree_cur *
+xfs_allocbt_dup_cursor(
+	struct xfs_btree_cur	*cur)
+{
+	return xfs_allocbt_init_cursor(cur->bc_mp, cur->bc_tp,
+			cur->bc_private.a.agbp, cur->bc_private.a.agno,
+			cur->bc_btnum);
+}
+
 /*
- * Update the record referred to by cur, to the value given by [bno, len].
- * This either works (return 0) or gets an EFSCORRUPTED error.
+ * Update the longest extent in the AGF
  */
-int					/* error */
-xfs_alloc_update(
-	xfs_btree_cur_t		*cur,	/* btree cursor */
-	xfs_agblock_t		bno,	/* starting block of extent */
-	xfs_extlen_t		len)	/* length of extent */
+STATIC void
+xfs_allocbt_update_lastrec(
+	struct xfs_btree_cur	*cur,
+	struct xfs_btree_block	*block,
+	union xfs_btree_rec	*rec,
+	int			ptr,
+	int			reason)
 {
-	xfs_alloc_block_t	*block;	/* btree block to update */
-	int			error;	/* error return value */
-	int			ptr;	/* current record number (updating) */
+	struct xfs_agf		*agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp);
+	xfs_agnumber_t		seqno = be32_to_cpu(agf->agf_seqno);
+	__be32			len;
 
-	ASSERT(len > 0);
-	/*
-	 * Pick up the a.g. freelist struct and the current block.
-	 */
-	block = XFS_BUF_TO_ALLOC_BLOCK(cur->bc_bufs[0]);
-#ifdef DEBUG
-	if ((error = xfs_btree_check_sblock(cur, block, 0, cur->bc_bufs[0])))
-		return error;
-#endif
-	/*
-	 * Get the address of the rec to be updated.
-	 */
-	ptr = cur->bc_ptrs[0];
-	{
-		xfs_alloc_rec_t		*rp;	/* pointer to updated record */
+	ASSERT(cur->bc_btnum == XFS_BTNUM_CNT);
 
-		rp = XFS_ALLOC_REC_ADDR(block, ptr, cur);
+	switch (reason) {
+	case LASTREC_UPDATE:
 		/*
-		 * Fill in the new contents and log them.
+		 * If this is the last leaf block and it's the last record,
+		 * then update the size of the longest extent in the AG.
 		 */
-		rp->ar_startblock = cpu_to_be32(bno);
-		rp->ar_blockcount = cpu_to_be32(len);
-		xfs_alloc_log_recs(cur, cur->bc_bufs[0], ptr, ptr);
-	}
-	/*
-	 * If it's the by-size btree and it's the last leaf block and
-	 * it's the last record... then update the size of the longest
-	 * extent in the a.g., which we cache in the a.g. freelist header.
-	 */
-	if (cur->bc_btnum == XFS_BTNUM_CNT &&
-	    be32_to_cpu(block->bb_rightsib) == NULLAGBLOCK &&
-	    ptr == be16_to_cpu(block->bb_numrecs)) {
-		xfs_agf_t	*agf;	/* a.g. freespace header */
-		xfs_agnumber_t	seqno;
-
-		agf = XFS_BUF_TO_AGF(cur->bc_private.a.agbp);
-		seqno = be32_to_cpu(agf->agf_seqno);
-		cur->bc_mp->m_perag[seqno].pagf_longest = len;
-		agf->agf_longest = cpu_to_be32(len);
-		xfs_alloc_log_agf(cur->bc_tp, cur->bc_private.a.agbp,
-			XFS_AGF_LONGEST);
-	}
-	/*
-	 * Updating first record in leaf. Pass new key value up to our parent.
-	 */
-	if (ptr == 1) {
-		xfs_alloc_key_t	key;	/* key containing [bno, len] */
-
-		key.ar_startblock = cpu_to_be32(bno);
-		key.ar_blockcount = cpu_to_be32(len);
-		if ((error = xfs_btree_updkey(cur, (union xfs_btree_key *)&key, 1)))
-			return error;
+		if (ptr != xfs_btree_get_numrecs(block))
+			return;
+		len = rec->alloc.ar_blockcount;
+		break;
+	default:
+		ASSERT(0);
+		return;
 	}
-	return 0;
-}
 
-STATIC struct xfs_btree_cur *
-xfs_allocbt_dup_cursor(
-	struct xfs_btree_cur	*cur)
-{
-	return xfs_allocbt_init_cursor(cur->bc_mp, cur->bc_tp,
-			cur->bc_private.a.agbp, cur->bc_private.a.agno,
-			cur->bc_btnum);
+	agf->agf_longest = len;
+	cur->bc_mp->m_perag[seqno].pagf_longest = be32_to_cpu(len);
+	xfs_alloc_log_agf(cur->bc_tp, cur->bc_private.a.agbp, XFS_AGF_LONGEST);
 }
 
 STATIC int
@@ -1864,6 +1831,7 @@ static const struct xfs_btree_ops xfs_allocbt_ops = {
 	.key_len		= sizeof(xfs_alloc_key_t),
 
 	.dup_cursor		= xfs_allocbt_dup_cursor,
+	.update_lastrec		= xfs_allocbt_update_lastrec,
 	.get_maxrecs		= xfs_allocbt_get_maxrecs,
 	.init_key_from_rec	= xfs_allocbt_init_key_from_rec,
 	.init_ptr_from_cur	= xfs_allocbt_init_ptr_from_cur,
@@ -1902,6 +1870,8 @@ xfs_allocbt_init_cursor(
 	cur->bc_blocklog = mp->m_sb.sb_blocklog;
 
 	cur->bc_ops = &xfs_allocbt_ops;
+	if (btnum == XFS_BTNUM_CNT)
+		cur->bc_flags = XFS_BTREE_LASTREC_UPDATE;
 
 	cur->bc_private.a.agbp = agbp;
 	cur->bc_private.a.agno = agno;

fs/xfs/xfs_alloc_btree.h

@@ -113,13 +113,6 @@ extern int xfs_alloc_get_rec(struct xfs_btree_cur *cur,	xfs_agblock_t *bno,
  */
 extern int xfs_alloc_insert(struct xfs_btree_cur *cur, int *stat);
 
-/*
- * Update the record referred to by cur, to the value given by [bno, len].
- * This either works (return 0) or gets an EFSCORRUPTED error.
- */
-extern int xfs_alloc_update(struct xfs_btree_cur *cur, xfs_agblock_t bno,
-				xfs_extlen_t len);
-
 
 extern struct xfs_btree_cur *xfs_allocbt_init_cursor(struct xfs_mount *,
 		struct xfs_trans *, struct xfs_buf *,

fs/xfs/xfs_bmap.c

@@ -430,6 +430,24 @@ xfs_bmbt_lookup_ge(
 	return xfs_btree_lookup(cur, XFS_LOOKUP_GE, stat);
 }
 
+/*
+* Update the record referred to by cur to the value given
+ * by [off, bno, len, state].
+ * This either works (return 0) or gets an EFSCORRUPTED error.
+ */
+STATIC int
+xfs_bmbt_update(
+	struct xfs_btree_cur	*cur,
+	xfs_fileoff_t		off,
+	xfs_fsblock_t		bno,
+	xfs_filblks_t		len,
+	xfs_exntst_t		state)
+{
+	union xfs_btree_rec	rec;
+
+	xfs_bmbt_disk_set_allf(&rec.bmbt, off, bno, len, state);
+	return xfs_btree_update(cur, &rec);
+}
 
 /*
  * Called from xfs_bmap_add_attrfork to handle btree format files.

fs/xfs/xfs_bmap_btree.c

@@ -1963,51 +1963,6 @@ xfs_bmbt_to_bmdr(
 	memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
 }
 
-/*
- * Update the record to the passed values.
- */
-int
-xfs_bmbt_update(
-	xfs_btree_cur_t		*cur,
-	xfs_fileoff_t		off,
-	xfs_fsblock_t		bno,
-	xfs_filblks_t		len,
-	xfs_exntst_t		state)
-{
-	xfs_bmbt_block_t	*block;
-	xfs_buf_t		*bp;
-	int			error;
-	xfs_bmbt_key_t		key;
-	int			ptr;
-	xfs_bmbt_rec_t		*rp;
-
-	XFS_BMBT_TRACE_CURSOR(cur, ENTRY);
-	XFS_BMBT_TRACE_ARGFFFI(cur, (xfs_dfiloff_t)off, (xfs_dfsbno_t)bno,
-		(xfs_dfilblks_t)len, (int)state);
-	block = xfs_bmbt_get_block(cur, 0, &bp);
-#ifdef DEBUG
-	if ((error = xfs_btree_check_lblock(cur, block, 0, bp))) {
-		XFS_BMBT_TRACE_CURSOR(cur, ERROR);
-		return error;
-	}
-#endif
-	ptr = cur->bc_ptrs[0];
-	rp = XFS_BMAP_REC_IADDR(block, ptr, cur);
-	xfs_bmbt_disk_set_allf(rp, off, bno, len, state);
-	xfs_bmbt_log_recs(cur, bp, ptr, ptr);
-	if (ptr > 1) {
-		XFS_BMBT_TRACE_CURSOR(cur, EXIT);
-		return 0;
-	}
-	key.br_startoff = cpu_to_be64(off);
-	if ((error = xfs_btree_updkey(cur, (union xfs_btree_key *)&key, 1))) {
-		XFS_BMBT_TRACE_CURSOR(cur, ERROR);
-		return error;
-	}
-	XFS_BMBT_TRACE_CURSOR(cur, EXIT);
-	return 0;
-}
-
 /*
  * Check extent records, which have just been read, for
  * any bit in the extent flag field. ASSERT on debug

fs/xfs/xfs_bmap_btree.h

@@ -274,8 +274,6 @@ extern void xfs_bmbt_disk_set_allf(xfs_bmbt_rec_t *r, xfs_fileoff_t o,
 			xfs_fsblock_t b, xfs_filblks_t c, xfs_exntst_t v);
 
 extern void xfs_bmbt_to_bmdr(xfs_bmbt_block_t *, int, xfs_bmdr_block_t *, int);
-extern int xfs_bmbt_update(struct xfs_btree_cur *, xfs_fileoff_t,
-				xfs_fsblock_t, xfs_filblks_t, xfs_exntst_t);
 
 extern struct xfs_btree_cur *xfs_bmbt_init_cursor(struct xfs_mount *,
 		struct xfs_trans *, struct xfs_inode *, int);

fs/xfs/xfs_btree.c

@@ -988,6 +988,30 @@ xfs_btree_get_sibling(
 	}
 }
 
+/*
+ * Return true if ptr is the last record in the btree and
+ * we need to track updateѕ to this record.  The decision
+ * will be further refined in the update_lastrec method.
+ */
+STATIC int
+xfs_btree_is_lastrec(
+	struct xfs_btree_cur	*cur,
+	struct xfs_btree_block	*block,
+	int			level)
+{
+	union xfs_btree_ptr	ptr;
+
+	if (level > 0)
+		return 0;
+	if (!(cur->bc_flags & XFS_BTREE_LASTREC_UPDATE))
+		return 0;
+
+	xfs_btree_get_sibling(cur, block, &ptr, XFS_BB_RIGHTSIB);
+	if (!xfs_btree_ptr_is_null(cur, &ptr))
+		return 0;
+	return 1;
+}
+
 STATIC xfs_daddr_t
 xfs_btree_ptr_to_daddr(
 	struct xfs_btree_cur	*cur,
@@ -1079,6 +1103,20 @@ xfs_btree_copy_keys(
 	memcpy(dst_key, src_key, numkeys * cur->bc_ops->key_len);
 }
 
+/*
+ * Copy records from one btree block to another.
+ */
+STATIC void
+xfs_btree_copy_recs(
+	struct xfs_btree_cur	*cur,
+	union xfs_btree_rec	*dst_rec,
+	union xfs_btree_rec	*src_rec,
+	int			numrecs)
+{
+	ASSERT(numrecs >= 0);
+	memcpy(dst_rec, src_rec, numrecs * cur->bc_ops->rec_len);
+}
+
 /*
  * Log key values from the btree block.
  */
@@ -1104,6 +1142,26 @@ xfs_btree_log_keys(
 	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
 }
 
+/*
+ * Log record values from the btree block.
+ */
+STATIC void
+xfs_btree_log_recs(
+	struct xfs_btree_cur	*cur,
+	struct xfs_buf		*bp,
+	int			first,
+	int			last)
+{
+	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
+	XFS_BTREE_TRACE_ARGBII(cur, bp, first, last);
+
+	xfs_trans_log_buf(cur->bc_tp, bp,
+			  xfs_btree_rec_offset(cur, first),
+			  xfs_btree_rec_offset(cur, last + 1) - 1);
+
+	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
+}
+
 /*
  * Increment cursor by one record at the level.
  * For nonzero levels the leaf-ward information is untouched.
@@ -1576,3 +1634,66 @@ xfs_btree_updkey(
 	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
 	return 0;
 }
+
+/*
+ * Update the record referred to by cur to the value in the
+ * given record. This either works (return 0) or gets an
+ * EFSCORRUPTED error.
+ */
+int
+xfs_btree_update(
+	struct xfs_btree_cur	*cur,
+	union xfs_btree_rec	*rec)
+{
+	struct xfs_btree_block	*block;
+	struct xfs_buf		*bp;
+	int			error;
+	int			ptr;
+	union xfs_btree_rec	*rp;
+
+	XFS_BTREE_TRACE_CURSOR(cur, XBT_ENTRY);
+	XFS_BTREE_TRACE_ARGR(cur, rec);
+
+	/* Pick up the current block. */
+	block = xfs_btree_get_block(cur, 0, &bp);
+
+#ifdef DEBUG
+	error = xfs_btree_check_block(cur, block, 0, bp);
+	if (error)
+		goto error0;
+#endif
+	/* Get the address of the rec to be updated. */
+	ptr = cur->bc_ptrs[0];
+	rp = xfs_btree_rec_addr(cur, ptr, block);
+
+	/* Fill in the new contents and log them. */
+	xfs_btree_copy_recs(cur, rp, rec, 1);
+	xfs_btree_log_recs(cur, bp, ptr, ptr);
+
+	/*
+	 * If we are tracking the last record in the tree and
+	 * we are at the far right edge of the tree, update it.
+	 */
+	if (xfs_btree_is_lastrec(cur, block, 0)) {
+		cur->bc_ops->update_lastrec(cur, block, rec,
+					    ptr, LASTREC_UPDATE);
+	}
+
+	/* Updating first rec in leaf. Pass new key value up to our parent. */
+	if (ptr == 1) {
+		union xfs_btree_key	key;
+
+		cur->bc_ops->init_key_from_rec(&key, rec);
+		error = xfs_btree_updkey(cur, &key, 1);
+		if (error)
+			goto error0;
+	}
+
+	XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
+	return 0;
+
+error0:
+	XFS_BTREE_TRACE_CURSOR(cur, XBT_ERROR);
+	return error;
+}
+

fs/xfs/xfs_btree.h

@@ -187,6 +187,12 @@ struct xfs_btree_ops {
 	/* cursor operations */
 	struct xfs_btree_cur *(*dup_cursor)(struct xfs_btree_cur *);
 
+	/* update last record information */
+	void	(*update_lastrec)(struct xfs_btree_cur *cur,
+				  struct xfs_btree_block *block,
+				  union xfs_btree_rec *rec,
+				  int ptr, int reason);
+
 	/* records in block/level */
 	int	(*get_maxrecs)(struct xfs_btree_cur *cur, int level);
 
@@ -220,6 +226,12 @@ struct xfs_btree_ops {
 #endif
 };
 
+/*
+ * Reasons for the update_lastrec method to be called.
+ */
+#define LASTREC_UPDATE	0
+
+
 /*
  * Btree cursor structure.
  * This collects all information needed by the btree code in one place.
@@ -264,6 +276,7 @@ typedef struct xfs_btree_cur
 /* cursor flags */
 #define XFS_BTREE_LONG_PTRS		(1<<0)	/* pointers are 64bits long */
 #define XFS_BTREE_ROOT_IN_INODE		(1<<1)	/* root may be variable size */
+#define XFS_BTREE_LASTREC_UPDATE	(1<<2)	/* track last rec externally */
 
 
 #define	XFS_BTREE_NOERROR	0
@@ -519,6 +532,7 @@ int xfs_btree_increment(struct xfs_btree_cur *, int, int *);
 int xfs_btree_decrement(struct xfs_btree_cur *, int, int *);
 int xfs_btree_lookup(struct xfs_btree_cur *, xfs_lookup_t, int *);
 int xfs_btree_updkey(struct xfs_btree_cur *, union xfs_btree_key *, int);
+int xfs_btree_update(struct xfs_btree_cur *, union xfs_btree_rec *);
 
 /*
  * Helpers.

fs/xfs/xfs_ialloc.c

@@ -171,6 +171,26 @@ xfs_inobt_lookup_le(
 	return xfs_btree_lookup(cur, XFS_LOOKUP_LE, stat);
 }
 
+/*
+ * Update the record referred to by cur to the value given
+ * by [ino, fcnt, free].
+ * This either works (return 0) or gets an EFSCORRUPTED error.
+ */
+STATIC int				/* error */
+xfs_inobt_update(
+	struct xfs_btree_cur	*cur,	/* btree cursor */
+	xfs_agino_t		ino,	/* starting inode of chunk */
+	__int32_t		fcnt,	/* free inode count */
+	xfs_inofree_t		free)	/* free inode mask */
+{
+	union xfs_btree_rec	rec;
+
+	rec.inobt.ir_startino = cpu_to_be32(ino);
+	rec.inobt.ir_freecount = cpu_to_be32(fcnt);
+	rec.inobt.ir_free = cpu_to_be64(free);
+	return xfs_btree_update(cur, &rec);
+}
+
 /*
  * Allocate new inodes in the allocation group specified by agbp.
  * Return 0 for success, else error code.

fs/xfs/xfs_ialloc_btree.c

@@ -1551,58 +1551,6 @@ xfs_inobt_insert(
 	return 0;
 }
 
-/*
- * Update the record referred to by cur, to the value given
- * by [ino, fcnt, free].
- * This either works (return 0) or gets an EFSCORRUPTED error.
- */
-int					/* error */
-xfs_inobt_update(
-	xfs_btree_cur_t		*cur,	/* btree cursor */
-	xfs_agino_t		ino,	/* starting inode of chunk */
-	__int32_t		fcnt,	/* free inode count */
-	xfs_inofree_t		free)	/* free inode mask */
-{
-	xfs_inobt_block_t	*block;	/* btree block to update */
-	xfs_buf_t		*bp;	/* buffer containing btree block */
-	int			error;	/* error return value */
-	int			ptr;	/* current record number (updating) */
-	xfs_inobt_rec_t		*rp;	/* pointer to updated record */
-
-	/*
-	 * Pick up the current block.
-	 */
-	bp = cur->bc_bufs[0];
-	block = XFS_BUF_TO_INOBT_BLOCK(bp);
-#ifdef DEBUG
-	if ((error = xfs_btree_check_sblock(cur, block, 0, bp)))
-		return error;
-#endif
-	/*
-	 * Get the address of the rec to be updated.
-	 */
-	ptr = cur->bc_ptrs[0];
-	rp = XFS_INOBT_REC_ADDR(block, ptr, cur);
-	/*
-	 * Fill in the new contents and log them.
-	 */
-	rp->ir_startino = cpu_to_be32(ino);
-	rp->ir_freecount = cpu_to_be32(fcnt);
-	rp->ir_free = cpu_to_be64(free);
-	xfs_inobt_log_recs(cur, bp, ptr, ptr);
-	/*
-	 * Updating first record in leaf. Pass new key value up to our parent.
-	 */
-	if (ptr == 1) {
-		xfs_inobt_key_t	key;	/* key containing [ino] */
-
-		key.ir_startino = cpu_to_be32(ino);
-		if ((error = xfs_btree_updkey(cur, (union xfs_btree_key *)&key, 1)))
-			return error;
-	}
-	return 0;
-}
-
 STATIC struct xfs_btree_cur *
 xfs_inobt_dup_cursor(
 	struct xfs_btree_cur	*cur)

fs/xfs/xfs_ialloc_btree.h

@@ -135,14 +135,6 @@ extern int xfs_inobt_get_rec(struct xfs_btree_cur *cur, xfs_agino_t *ino,
  */
 extern int xfs_inobt_insert(struct xfs_btree_cur *cur, int *stat);
 
-/*
- * Update the record referred to by cur, to the value given
- * by [ino, fcnt, free].
- * This either works (return 0) or gets an EFSCORRUPTED error.
- */
-extern int xfs_inobt_update(struct xfs_btree_cur *cur, xfs_agino_t ino,
-				__int32_t fcnt, xfs_inofree_t free);
-
 
 extern struct xfs_btree_cur *xfs_inobt_init_cursor(struct xfs_mount *,
 		struct xfs_trans *, struct xfs_buf *, xfs_agnumber_t);