xfs: define the on-disk refcount btree format
Start constructing the refcount btree implementation by establishing
the on-disk format and everything needed to read, write, and
manipulate the refcount btree blocks.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/xfs/libxfs/xfs_refcount_btree.c b/fs/xfs/libxfs/xfs_refcount_btree.c
new file mode 100644
index 0000000..359cf0c
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_refcount_btree.c
@@ -0,0 +1,178 @@
+/*
+ * Copyright (C) 2016 Oracle. All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_sb.h"
+#include "xfs_mount.h"
+#include "xfs_btree.h"
+#include "xfs_bmap.h"
+#include "xfs_refcount_btree.h"
+#include "xfs_alloc.h"
+#include "xfs_error.h"
+#include "xfs_trace.h"
+#include "xfs_cksum.h"
+#include "xfs_trans.h"
+#include "xfs_bit.h"
+
+static struct xfs_btree_cur *
+xfs_refcountbt_dup_cursor(
+ struct xfs_btree_cur *cur)
+{
+ return xfs_refcountbt_init_cursor(cur->bc_mp, cur->bc_tp,
+ cur->bc_private.a.agbp, cur->bc_private.a.agno,
+ cur->bc_private.a.dfops);
+}
+
+STATIC bool
+xfs_refcountbt_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;
+
+ if (block->bb_magic != cpu_to_be32(XFS_REFC_CRC_MAGIC))
+ return false;
+
+ if (!xfs_sb_version_hasreflink(&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_refcount_level)
+ return false;
+ } else if (level >= mp->m_refc_maxlevels)
+ return false;
+
+ return xfs_btree_sblock_verify(bp, mp->m_refc_mxr[level != 0]);
+}
+
+STATIC void
+xfs_refcountbt_read_verify(
+ struct xfs_buf *bp)
+{
+ if (!xfs_btree_sblock_verify_crc(bp))
+ xfs_buf_ioerror(bp, -EFSBADCRC);
+ else if (!xfs_refcountbt_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_refcountbt_write_verify(
+ struct xfs_buf *bp)
+{
+ if (!xfs_refcountbt_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_refcountbt_buf_ops = {
+ .name = "xfs_refcountbt",
+ .verify_read = xfs_refcountbt_read_verify,
+ .verify_write = xfs_refcountbt_write_verify,
+};
+
+static const struct xfs_btree_ops xfs_refcountbt_ops = {
+ .rec_len = sizeof(struct xfs_refcount_rec),
+ .key_len = sizeof(struct xfs_refcount_key),
+
+ .dup_cursor = xfs_refcountbt_dup_cursor,
+ .buf_ops = &xfs_refcountbt_buf_ops,
+};
+
+/*
+ * Allocate a new refcount btree cursor.
+ */
+struct xfs_btree_cur *
+xfs_refcountbt_init_cursor(
+ struct xfs_mount *mp,
+ struct xfs_trans *tp,
+ struct xfs_buf *agbp,
+ xfs_agnumber_t agno,
+ struct xfs_defer_ops *dfops)
+{
+ struct xfs_agf *agf = XFS_BUF_TO_AGF(agbp);
+ struct xfs_btree_cur *cur;
+
+ ASSERT(agno != NULLAGNUMBER);
+ ASSERT(agno < mp->m_sb.sb_agcount);
+ cur = kmem_zone_zalloc(xfs_btree_cur_zone, KM_NOFS);
+
+ cur->bc_tp = tp;
+ cur->bc_mp = mp;
+ cur->bc_btnum = XFS_BTNUM_REFC;
+ cur->bc_blocklog = mp->m_sb.sb_blocklog;
+ cur->bc_ops = &xfs_refcountbt_ops;
+
+ cur->bc_nlevels = be32_to_cpu(agf->agf_refcount_level);
+
+ cur->bc_private.a.agbp = agbp;
+ cur->bc_private.a.agno = agno;
+ cur->bc_private.a.dfops = dfops;
+ cur->bc_flags |= XFS_BTREE_CRC_BLOCKS;
+
+ cur->bc_private.a.priv.refc.nr_ops = 0;
+ cur->bc_private.a.priv.refc.shape_changes = 0;
+
+ return cur;
+}
+
+/*
+ * Calculate the number of records in a refcount btree block.
+ */
+int
+xfs_refcountbt_maxrecs(
+ struct xfs_mount *mp,
+ int blocklen,
+ bool leaf)
+{
+ blocklen -= XFS_REFCOUNT_BLOCK_LEN;
+
+ if (leaf)
+ return blocklen / sizeof(struct xfs_refcount_rec);
+ return blocklen / (sizeof(struct xfs_refcount_key) +
+ sizeof(xfs_refcount_ptr_t));
+}
+
+/* Compute the maximum height of a refcount btree. */
+void
+xfs_refcountbt_compute_maxlevels(
+ struct xfs_mount *mp)
+{
+ mp->m_refc_maxlevels = xfs_btree_compute_maxlevels(mp,
+ mp->m_refc_mnr, mp->m_sb.sb_agblocks);
+}