[PATCH 12/29] xfs: wire up a new inode fork type for the realtime rmap

Plumb in the pieces we need to embed the root of the realtime rmap
btree in an inode's data fork, complete with new fork type and
on-disk interpretation functions.

Signed-off-by: Darrick J. Wong <[email protected]>
---
 libxfs/xfs_format.h       |    8 +
 libxfs/xfs_inode_fork.c   |   48 ++++++++-
 libxfs/xfs_rtrmap_btree.c |  250 +++++++++++++++++++++++++++++++++++++++++++++
 libxfs/xfs_rtrmap_btree.h |   49 +++++++++
 4 files changed, 353 insertions(+), 2 deletions(-)


diff --git a/libxfs/xfs_format.h b/libxfs/xfs_format.h
index 5fb5e52..b3f595e 100644
--- a/libxfs/xfs_format.h
+++ b/libxfs/xfs_format.h
@@ -1478,6 +1478,14 @@ typedef __be32 xfs_rmap_ptr_t;
 #define	XFS_RTRMAP_CRC_MAGIC	0x4d415052	/* 'MAPR' */
 
 /*
+ * rtrmap root header, on-disk form only.
+ */
+struct xfs_rtrmap_root {
+	__be16		bb_level;	/* 0 is a leaf */
+	__be16		bb_numrecs;	/* current # of data records */
+};
+
+/*
  * Data record structure
  */
 struct xfs_rtrmap_rec {
diff --git a/libxfs/xfs_inode_fork.c b/libxfs/xfs_inode_fork.c
index b006e2f..b0dea20 100644
--- a/libxfs/xfs_inode_fork.c
+++ b/libxfs/xfs_inode_fork.c
@@ -28,12 +28,14 @@
 #include "xfs_trace.h"
 #include "xfs_attr_sf.h"
 #include "xfs_da_format.h"
+#include "xfs_rtrmap_btree.h"
 
 kmem_zone_t *xfs_ifork_zone;
 
 STATIC int xfs_iformat_local(xfs_inode_t *, xfs_dinode_t *, int, int);
 STATIC int xfs_iformat_extents(xfs_inode_t *, xfs_dinode_t *, int);
 STATIC int xfs_iformat_btree(xfs_inode_t *, xfs_dinode_t *, int);
+STATIC int xfs_iformat_rmap(struct xfs_inode *, struct xfs_dinode *);
 
 #ifdef DEBUG
 /*
@@ -196,7 +198,7 @@ xfs_iformat_fork(
 				return -EFSCORRUPTED;
 			if (ip->i_ino != ip->i_mount->m_sb.sb_rrmapino)
 				return -EFSCORRUPTED;
-			/* to be implemented later */
+			error = xfs_iformat_rmap(ip, dip);
 			break;
 		default:
 			XFS_ERROR_REPORT("xfs_iformat(6)", XFS_ERRLEVEL_LOW,
@@ -472,6 +474,37 @@ xfs_iformat_btree(
 	return 0;
 }
 
+/* The file is a reverse mapping tree. */
+STATIC int
+xfs_iformat_rmap(
+	struct xfs_inode	*ip,
+	struct xfs_dinode	*dip)
+{
+	struct xfs_rtrmap_root	*dfp;
+	struct xfs_ifork	*ifp;
+	/* REFERENCED */
+	int			size;
+	int			whichfork = XFS_DATA_FORK;
+
+	ifp = XFS_IFORK_PTR(ip, whichfork);
+	dfp = (struct xfs_rtrmap_root *)XFS_DFORK_PTR(dip, whichfork);
+	size = XFS_RTRMAP_BROOT_SPACE(dfp);
+
+	ifp->if_broot_bytes = size;
+	ifp->if_broot = kmem_alloc(size, KM_SLEEP | KM_NOFS);
+	ASSERT(ifp->if_broot != NULL);
+	/*
+	 * Copy and convert from the on-disk structure
+	 * to the in-memory structure.
+	 */
+	xfs_rtrmapbt_from_disk(ip, dfp,
+			XFS_DFORK_SIZE(dip, ip->i_mount, whichfork),
+			ifp->if_broot, size);
+	ifp->if_flags = XFS_IFBROOT;
+
+	return 0;
+}
+
 /*
  * Read in extents from a btree-format inode.
  * Allocate and fill in if_extents.  Real work is done in xfs_bmap.c.
@@ -801,7 +834,18 @@ xfs_iflush_fork(
 		break;
 
 	case XFS_DINODE_FMT_RMAP:
-		/* to be implemented later */
+		ASSERT(whichfork == XFS_DATA_FORK);
+		ASSERT(ip->i_ino == mp->m_sb.sb_rrmapino);
+		if ((iip->ili_fields & brootflag[whichfork]) &&
+		    (ifp->if_broot_bytes > 0)) {
+			ASSERT(ifp->if_broot != NULL);
+			ASSERT(XFS_RTRMAP_ROOT_SPACE(ifp->if_broot) <=
+			        XFS_IFORK_SIZE(ip, whichfork));
+			xfs_rtrmapbt_to_disk(mp, ifp->if_broot,
+				ifp->if_broot_bytes,
+				(struct xfs_rtrmap_root *)cp,
+				XFS_DFORK_SIZE(dip, mp, whichfork));
+		}
 		break;
 
 	default:
diff --git a/libxfs/xfs_rtrmap_btree.c b/libxfs/xfs_rtrmap_btree.c
index e4dbe88..503e64e 100644
--- a/libxfs/xfs_rtrmap_btree.c
+++ b/libxfs/xfs_rtrmap_btree.c
@@ -222,6 +222,42 @@ xfs_rtrmapbt_get_maxrecs(
 	return cur->bc_mp->m_rtrmap_mxr[level != 0];
 }
 
+/*
+ * Calculate number of records in a realtime rmap btree inode root.
+ */
+STATIC int
+xfs_rtrmapbt_root_maxrecs(
+	int			blocklen,
+	bool			leaf)
+{
+	blocklen -= sizeof(struct xfs_rtrmap_root);
+
+	if (leaf)
+		return blocklen / sizeof(struct xfs_rtrmap_rec);
+	return blocklen / (2 * sizeof(struct xfs_rtrmap_key) +
+			sizeof(xfs_rtrmap_ptr_t));
+}
+
+/*
+ * Get the maximum records we could store in the on-disk format.
+ *
+ * For non-root nodes this is equivalent to xfs_bmbt_get_maxrecs, but
+ * for the root node this checks the available space in the dinode fork
+ * so that we can resize the in-memory buffer to match it.  After a
+ * resize to the maximum size this function returns the same value
+ * as xfs_bmbt_get_maxrecs for the root node, too.
+ */
+STATIC int
+xfs_rtrmapbt_get_dmaxrecs(
+	struct xfs_btree_cur	*cur,
+	int			level)
+{
+	if (level != cur->bc_nlevels - 1)
+		return cur->bc_mp->m_rtrmap_mxr[level != 0];
+	return xfs_rtrmapbt_root_maxrecs(cur->bc_private.b.forksize,
+			level == 0);
+}
+
 STATIC void
 xfs_rtrmapbt_init_key_from_rec(
 	union xfs_btree_key	*key,
@@ -339,6 +375,129 @@ xfs_rtrmapbt_diff_two_keys(
 	return 0;
 }
 
+/*
+ * Reallocate the space for if_broot based on the number of records
+ * being added or deleted as indicated in rec_diff.  Move the records
+ * and pointers in if_broot to fit the new size.  When shrinking this
+ * will eliminate holes between the records and pointers created by
+ * the caller.  When growing this will create holes to be filled in
+ * by the caller.
+ *
+ * The caller must not request to add more records than would fit in
+ * the on-disk inode root.  If the if_broot is currently NULL, then
+ * if we are adding records, one will be allocated.  The caller must also
+ * not request that the number of records go below zero, although
+ * it can go to zero.
+ */
+STATIC void
+xfs_rtrmapbt_iroot_realloc(
+	struct xfs_btree_cur	*cur,
+	int			rec_diff)
+{
+	struct xfs_inode	*ip = cur->bc_private.b.ip;
+	int			whichfork = cur->bc_private.b.whichfork;
+	struct xfs_mount	*mp = ip->i_mount;
+	int			cur_max;
+	struct xfs_ifork	*ifp;
+	struct xfs_btree_block	*new_broot;
+	struct xfs_btree_block	*broot;
+	int			new_max;
+	size_t			new_size;
+	char			*np;
+	char			*op;
+	int			level;
+
+	/*
+	 * Handle the degenerate case quietly.
+	 */
+	if (rec_diff == 0) {
+		return;
+	}
+
+	ifp = XFS_IFORK_PTR(ip, whichfork);
+	if (rec_diff > 0) {
+		/*
+		 * If there wasn't any memory allocated before, just
+		 * allocate it now and get out.
+		 */
+		if (ifp->if_broot_bytes == 0) {
+			new_size = XFS_RTRMAP_BROOT_SPACE_CALC(rec_diff,
+					cur->bc_nlevels - 1);
+			ifp->if_broot = kmem_alloc(new_size,
+					KM_SLEEP | KM_NOFS);
+			ifp->if_broot_bytes = (int)new_size;
+			return;
+		}
+
+		/*
+		 * If there is already an existing if_broot, then we need
+		 * to realloc() it and shift the pointers to their new
+		 * location.  The records don't change location because
+		 * they are kept butted up against the btree block header.
+		 */
+		broot = (struct xfs_btree_block *)ifp->if_broot;
+		level = be16_to_cpu(broot->bb_level);
+		cur_max = xfs_rtrmapbt_maxrecs(mp, ifp->if_broot_bytes,
+				level == 0);
+		new_max = cur_max + rec_diff;
+		new_size = XFS_RTRMAP_BROOT_SPACE_CALC(new_max, level);
+		ifp->if_broot = kmem_realloc(ifp->if_broot, new_size,
+				KM_SLEEP | KM_NOFS);
+		if (level > 0) {
+			op = (char *)XFS_RTRMAP_BROOT_PTR_ADDR(ifp->if_broot,
+					1, ifp->if_broot_bytes);
+			np = (char *)XFS_RTRMAP_BROOT_PTR_ADDR(ifp->if_broot,
+					1, (int)new_size);
+			memmove(np, op, cur_max * sizeof(xfs_fsblock_t));
+		}
+		ifp->if_broot_bytes = (int)new_size;
+		ASSERT(XFS_RTRMAP_ROOT_SPACE(ifp->if_broot) <=
+				XFS_IFORK_SIZE(ip, whichfork));
+		return;
+	}
+
+	/*
+	 * rec_diff is less than 0.  In this case, we are shrinking the
+	 * if_broot buffer.  It must already exist.  If we go to zero
+	 * records, just get rid of the root and clear the status bit.
+	 */
+	ASSERT((ifp->if_broot != NULL) && (ifp->if_broot_bytes > 0));
+	broot = (struct xfs_btree_block *)ifp->if_broot;
+	level = be16_to_cpu(broot->bb_level);
+	cur_max = xfs_rtrmapbt_maxrecs(mp, ifp->if_broot_bytes, level == 0);
+	new_max = cur_max + rec_diff;
+	if (new_max < 0)
+		new_max = 0;
+	new_size = XFS_RTRMAP_BROOT_SPACE_CALC(new_max, level);
+	new_broot = kmem_alloc(new_size, KM_SLEEP | KM_NOFS);
+	memcpy(new_broot, ifp->if_broot, XFS_RTRMAP_BLOCK_LEN);
+
+	/* Copy the records or keys and pointers. */
+	if (level > 0) {
+		op = (char *)XFS_RTRMAP_KEY_ADDR(ifp->if_broot, 1);
+		np = (char *)XFS_RTRMAP_KEY_ADDR(new_broot, 1);
+		memcpy(np, op, new_max * 2 * sizeof(struct xfs_rtrmap_key));
+
+		op = (char *)XFS_RTRMAP_BROOT_PTR_ADDR(ifp->if_broot, 1,
+				ifp->if_broot_bytes);
+		np = (char *)XFS_RTRMAP_BROOT_PTR_ADDR(new_broot, 1,
+				(int)new_size);
+		memcpy(np, op, new_max * sizeof(xfs_fsblock_t));
+	} else {
+		op = (char *)XFS_RTRMAP_REC_ADDR(ifp->if_broot, 1);
+		np = (char *)XFS_RTRMAP_REC_ADDR(new_broot, 1);
+		memcpy(np, op, new_max * sizeof(struct xfs_rtrmap_rec));
+	}
+
+	kmem_free(ifp->if_broot);
+	ifp->if_broot = new_broot;
+	ifp->if_broot_bytes = (int)new_size;
+	if (ifp->if_broot)
+		ASSERT(XFS_RTRMAP_ROOT_SPACE(ifp->if_broot) <=
+				XFS_IFORK_SIZE(ip, whichfork));
+	return;
+}
+
 static bool
 xfs_rtrmapbt_verify(
 	struct xfs_buf		*bp)
@@ -441,12 +600,14 @@ static const struct xfs_btree_ops xfs_rtrmapbt_ops = {
 	.free_block		= xfs_rtrmapbt_free_block,
 	.get_minrecs		= xfs_rtrmapbt_get_minrecs,
 	.get_maxrecs		= xfs_rtrmapbt_get_maxrecs,
+	.get_dmaxrecs		= xfs_rtrmapbt_get_dmaxrecs,
 	.init_key_from_rec	= xfs_rtrmapbt_init_key_from_rec,
 	.init_high_key_from_rec	= xfs_rtrmapbt_init_high_key_from_rec,
 	.init_rec_from_cur	= xfs_rtrmapbt_init_rec_from_cur,
 	.init_ptr_from_cur	= xfs_rtrmapbt_init_ptr_from_cur,
 	.key_diff		= xfs_rtrmapbt_key_diff,
 	.buf_ops		= &xfs_rtrmapbt_buf_ops,
+	.iroot_realloc		= xfs_rtrmapbt_iroot_realloc,
 	.diff_two_keys		= xfs_rtrmapbt_diff_two_keys,
 	.keys_inorder		= xfs_rtrmapbt_keys_inorder,
 	.recs_inorder		= xfs_rtrmapbt_recs_inorder,
@@ -512,3 +673,92 @@ xfs_rtrmapbt_compute_maxlevels(
 			mp->m_rtrmap_mnr, mp->m_sb.sb_rblocks);
 	ASSERT(mp->m_rtrmap_maxlevels <= XFS_BTREE_MAXLEVELS);
 }
+
+/*
+ * Convert on-disk form of btree root to in-memory form.
+ */
+void
+xfs_rtrmapbt_from_disk(
+	struct xfs_inode	*ip,
+	struct xfs_rtrmap_root	*dblock,
+	int			dblocklen,
+	struct xfs_btree_block	*rblock,
+	int			rblocklen)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	int			dmxr;
+	struct xfs_rtrmap_key	*fkp;
+	__be64			*fpp;
+	struct xfs_rtrmap_key	*tkp;
+	__be64			*tpp;
+	struct xfs_rtrmap_rec	*frp;
+	struct xfs_rtrmap_rec	*trp;
+
+	xfs_btree_init_block_int(mp, rblock, XFS_BUF_DADDR_NULL,
+			 XFS_RTRMAP_CRC_MAGIC, 0, 0, ip->i_ino,
+			 XFS_BTREE_LONG_PTRS | XFS_BTREE_CRC_BLOCKS);
+
+	rblock->bb_level = dblock->bb_level;
+	rblock->bb_numrecs = dblock->bb_numrecs;
+
+	if (be16_to_cpu(rblock->bb_level) > 0) {
+		dmxr = xfs_rtrmapbt_maxrecs(mp, dblocklen, 0);
+		fkp = XFS_RTRMAP_ROOT_KEY_ADDR(dblock, 1);
+		tkp = XFS_RTRMAP_KEY_ADDR(rblock, 1);
+		fpp = XFS_RTRMAP_ROOT_PTR_ADDR(dblock, 1, dmxr);
+		tpp = XFS_RTRMAP_BROOT_PTR_ADDR(rblock, 1, rblocklen);
+		dmxr = be16_to_cpu(dblock->bb_numrecs);
+		memcpy(tkp, fkp, 2 * sizeof(*fkp) * dmxr);
+		memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
+	} else {
+		frp = XFS_RTRMAP_ROOT_REC_ADDR(dblock, 1);
+		trp = XFS_RTRMAP_REC_ADDR(rblock, 1);
+		dmxr = be16_to_cpu(dblock->bb_numrecs);
+		memcpy(trp, frp, sizeof(*frp) * dmxr);
+	}
+}
+
+/*
+ * Convert in-memory form of btree root to on-disk form.
+ */
+void
+xfs_rtrmapbt_to_disk(
+	struct xfs_mount	*mp,
+	struct xfs_btree_block	*rblock,
+	int			rblocklen,
+	struct xfs_rtrmap_root	*dblock,
+	int			dblocklen)
+{
+	int			dmxr;
+	struct xfs_rtrmap_key	*fkp;
+	__be64			*fpp;
+	struct xfs_rtrmap_key	*tkp;
+	__be64			*tpp;
+	struct xfs_rtrmap_rec	*frp;
+	struct xfs_rtrmap_rec	*trp;
+
+	ASSERT(rblock->bb_magic == cpu_to_be32(XFS_RTRMAP_CRC_MAGIC));
+	ASSERT(uuid_equal(&rblock->bb_u.l.bb_uuid, &mp->m_sb.sb_meta_uuid));
+	ASSERT(rblock->bb_u.l.bb_blkno == cpu_to_be64(XFS_BUF_DADDR_NULL));
+	ASSERT(rblock->bb_u.l.bb_leftsib == cpu_to_be64(NULLFSBLOCK));
+	ASSERT(rblock->bb_u.l.bb_rightsib == cpu_to_be64(NULLFSBLOCK));
+
+	dblock->bb_level = rblock->bb_level;
+	dblock->bb_numrecs = rblock->bb_numrecs;
+
+	if (be16_to_cpu(rblock->bb_level) > 0) {
+		dmxr = xfs_rtrmapbt_maxrecs(mp, dblocklen, 0);
+		fkp = XFS_RTRMAP_KEY_ADDR(rblock, 1);
+		tkp = XFS_RTRMAP_ROOT_KEY_ADDR(dblock, 1);
+		fpp = XFS_RTRMAP_BROOT_PTR_ADDR(rblock, 1, rblocklen);
+		tpp = XFS_RTRMAP_ROOT_PTR_ADDR(dblock, 1, dmxr);
+		dmxr = be16_to_cpu(rblock->bb_numrecs);
+		memcpy(tkp, fkp, 2 * sizeof(*fkp) * dmxr);
+		memcpy(tpp, fpp, sizeof(*fpp) * dmxr);
+	} else {
+		frp = XFS_RTRMAP_REC_ADDR(rblock, 1);
+		trp = XFS_RTRMAP_ROOT_REC_ADDR(dblock, 1);
+		dmxr = be16_to_cpu(rblock->bb_numrecs);
+		memcpy(trp, frp, sizeof(*frp) * dmxr);
+	}
+}
diff --git a/libxfs/xfs_rtrmap_btree.h b/libxfs/xfs_rtrmap_btree.h
index 5eb19f4..51adc0c 100644
--- a/libxfs/xfs_rtrmap_btree.h
+++ b/libxfs/xfs_rtrmap_btree.h
@@ -54,9 +54,58 @@ struct xfs_mount;
 		 (maxrecs) * 2 * sizeof(struct xfs_rtrmap_key) + \
 		 ((index) - 1) * sizeof(xfs_rtrmap_ptr_t)))
 
+/* Macros for handling the inode root */
+
+#define XFS_RTRMAP_ROOT_REC_ADDR(block, index) \
+	((struct xfs_rtrmap_rec *) \
+		((char *)(block) + \
+		 sizeof(struct xfs_rtrmap_root) + \
+		 ((index) - 1) * sizeof(struct xfs_rtrmap_rec)))
+
+#define XFS_RTRMAP_ROOT_KEY_ADDR(block, index) \
+	((struct xfs_rtrmap_key *) \
+		((char *)(block) + \
+		 sizeof(struct xfs_rtrmap_root) + \
+		 ((index) - 1) * 2 * sizeof(struct xfs_rtrmap_key)))
+
+#define XFS_RTRMAP_ROOT_PTR_ADDR(block, index, maxrecs) \
+	((xfs_rtrmap_ptr_t *) \
+		((char *)(block) + \
+		 sizeof(struct xfs_rtrmap_root) + \
+		 (maxrecs) * 2 * sizeof(struct xfs_rtrmap_key) + \
+		 ((index) - 1) * sizeof(xfs_rtrmap_ptr_t)))
+
+#define XFS_RTRMAP_BROOT_PTR_ADDR(bb, i, sz) \
+	XFS_RTRMAP_PTR_ADDR(bb, i, xfs_rtrmapbt_maxrecs(mp, sz, 0))
+
+#define XFS_RTRMAP_BROOT_SPACE_CALC(nrecs, level) \
+	(int)(XFS_RTRMAP_BLOCK_LEN + ((level) > 0 ? \
+	       ((nrecs) * (2 * sizeof(struct xfs_rtrmap_key) + sizeof(xfs_rtrmap_ptr_t))) : \
+	       ((nrecs) * sizeof(struct xfs_rtrmap_rec))))
+
+#define XFS_RTRMAP_BROOT_SPACE(bb) \
+	(XFS_RTRMAP_BROOT_SPACE_CALC(be16_to_cpu((bb)->bb_numrecs), \
+				     be16_to_cpu((bb)->bb_level)))
+
+#define XFS_RTRMAP_ROOT_SPACE_CALC(nrecs, level) \
+	(int)(sizeof(struct xfs_rtrmap_root) + ((level) > 0 ? \
+	       ((nrecs) * (2 * sizeof(struct xfs_rtrmap_key) + sizeof(xfs_rtrmap_ptr_t))) : \
+	       ((nrecs) * sizeof(struct xfs_rtrmap_rec))))
+
+#define XFS_RTRMAP_ROOT_SPACE(bb) \
+	(XFS_RTRMAP_ROOT_SPACE_CALC(be16_to_cpu((bb)->bb_numrecs), \
+				    be16_to_cpu((bb)->bb_level)))
+
 struct xfs_btree_cur *xfs_rtrmapbt_init_cursor(struct xfs_mount *mp,
 				struct xfs_trans *tp, struct xfs_inode *ip);
 int xfs_rtrmapbt_maxrecs(struct xfs_mount *mp, int blocklen, bool leaf);
 extern void xfs_rtrmapbt_compute_maxlevels(struct xfs_mount *mp);
 
+void xfs_rtrmapbt_from_disk(struct xfs_inode *ip,
+		struct xfs_rtrmap_root *dblock, int dblocklen,
+		struct xfs_btree_block *rblock, int rblocklen);
+void xfs_rtrmapbt_to_disk(struct xfs_mount *mp,
+		struct xfs_btree_block *rblock, int rblocklen,
+		struct xfs_rtrmap_root *dblock, int dblocklen);
+
 #endif	/* __XFS_RTRMAP_BTREE_H__ */

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