xfs: add rmap btree growfs support

Originally-From: Dave Chinner <dchinner@redhat.com>

Now we can read and write rmap btree blocks, we can add support to
the growfs code to initialise new rmap btree blocks.

[darrick.wong@oracle.com: fill out the rmap offset fields]
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/xfs_fsops.c

@@ -33,6 +33,7 @@
 #include "xfs_btree.h"
 #include "xfs_alloc_btree.h"
 #include "xfs_alloc.h"
+#include "xfs_rmap_btree.h"
 #include "xfs_ialloc.h"
 #include "xfs_fsops.h"
 #include "xfs_itable.h"
@@ -241,6 +242,12 @@ xfs_growfs_data_private(
 		agf->agf_roots[XFS_BTNUM_CNTi] = cpu_to_be32(XFS_CNT_BLOCK(mp));
 		agf->agf_levels[XFS_BTNUM_BNOi] = cpu_to_be32(1);
 		agf->agf_levels[XFS_BTNUM_CNTi] = cpu_to_be32(1);
+		if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
+			agf->agf_roots[XFS_BTNUM_RMAPi] =
+						cpu_to_be32(XFS_RMAP_BLOCK(mp));
+			agf->agf_levels[XFS_BTNUM_RMAPi] = cpu_to_be32(1);
+		}
+
 		agf->agf_flfirst = cpu_to_be32(1);
 		agf->agf_fllast = 0;
 		agf->agf_flcount = 0;
@@ -380,6 +387,72 @@ xfs_growfs_data_private(
 		if (error)
 			goto error0;
 
+		/* RMAP btree root block */
+		if (xfs_sb_version_hasrmapbt(&mp->m_sb)) {
+			struct xfs_rmap_rec	*rrec;
+			struct xfs_btree_block	*block;
+
+			bp = xfs_growfs_get_hdr_buf(mp,
+				XFS_AGB_TO_DADDR(mp, agno, XFS_RMAP_BLOCK(mp)),
+				BTOBB(mp->m_sb.sb_blocksize), 0,
+				&xfs_rmapbt_buf_ops);
+			if (!bp) {
+				error = -ENOMEM;
+				goto error0;
+			}
+
+			xfs_btree_init_block(mp, bp, XFS_RMAP_CRC_MAGIC, 0, 0,
+						agno, XFS_BTREE_CRC_BLOCKS);
+			block = XFS_BUF_TO_BLOCK(bp);
+
+
+			/*
+			 * mark the AG header regions as static metadata The BNO
+			 * btree block is the first block after the headers, so
+			 * it's location defines the size of region the static
+			 * metadata consumes.
+			 *
+			 * Note: unlike mkfs, we never have to account for log
+			 * space when growing the data regions
+			 */
+			rrec = XFS_RMAP_REC_ADDR(block, 1);
+			rrec->rm_startblock = 0;
+			rrec->rm_blockcount = cpu_to_be32(XFS_BNO_BLOCK(mp));
+			rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_FS);
+			rrec->rm_offset = 0;
+			be16_add_cpu(&block->bb_numrecs, 1);
+
+			/* account freespace btree root blocks */
+			rrec = XFS_RMAP_REC_ADDR(block, 2);
+			rrec->rm_startblock = cpu_to_be32(XFS_BNO_BLOCK(mp));
+			rrec->rm_blockcount = cpu_to_be32(2);
+			rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
+			rrec->rm_offset = 0;
+			be16_add_cpu(&block->bb_numrecs, 1);
+
+			/* account inode btree root blocks */
+			rrec = XFS_RMAP_REC_ADDR(block, 3);
+			rrec->rm_startblock = cpu_to_be32(XFS_IBT_BLOCK(mp));
+			rrec->rm_blockcount = cpu_to_be32(XFS_RMAP_BLOCK(mp) -
+							XFS_IBT_BLOCK(mp));
+			rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_INOBT);
+			rrec->rm_offset = 0;
+			be16_add_cpu(&block->bb_numrecs, 1);
+
+			/* account for rmap btree root */
+			rrec = XFS_RMAP_REC_ADDR(block, 4);
+			rrec->rm_startblock = cpu_to_be32(XFS_RMAP_BLOCK(mp));
+			rrec->rm_blockcount = cpu_to_be32(1);
+			rrec->rm_owner = cpu_to_be64(XFS_RMAP_OWN_AG);
+			rrec->rm_offset = 0;
+			be16_add_cpu(&block->bb_numrecs, 1);
+
+			error = xfs_bwrite(bp);
+			xfs_buf_relse(bp);
+			if (error)
+				goto error0;
+		}
+
 		/*
 		 * INO btree root block
 		 */