--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2021-2024 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#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_bit.h"
+#include "xfs_sb.h"
+#include "xfs_mount.h"
+#include "xfs_defer.h"
+#include "xfs_inode.h"
+#include "xfs_trans.h"
+#include "xfs_alloc.h"
+#include "xfs_btree.h"
+#include "xfs_btree_staging.h"
+#include "xfs_rtrefcount_btree.h"
+#include "xfs_trace.h"
+#include "xfs_cksum.h"
+#include "xfs_error.h"
+#include "xfs_extent_busy.h"
+#include "xfs_rtgroup.h"
+#include "xfs_rtbitmap.h"
+
+static struct kmem_cache *xfs_rtrefcountbt_cur_cache;
+
+/*
+ * Realtime Reference Count btree.
+ *
+ * This is a btree used to track the owner(s) of a given extent in the realtime
+ * device. See the comments in xfs_refcount_btree.c for more information.
+ *
+ * This tree is basically the same as the regular refcount btree except that
+ * it's rooted in an inode.
+ */
+
+static struct xfs_btree_cur *
+xfs_rtrefcountbt_dup_cursor(
+ struct xfs_btree_cur *cur)
+{
+ struct xfs_btree_cur *new;
+
+ new = xfs_rtrefcountbt_init_cursor(cur->bc_mp, cur->bc_tp,
+ to_rtg(cur->bc_group), cur->bc_ino.ip);
+
+ return new;
+}
+
+static xfs_failaddr_t
+xfs_rtrefcountbt_verify(
+ struct xfs_buf *bp)
+{
+ struct xfs_mount *mp = bp->b_target->bt_mount;
+ struct xfs_btree_block *block = XFS_BUF_TO_BLOCK(bp);
+ xfs_failaddr_t fa;
+ int level;
+
+ if (!xfs_verify_magic(bp, block->bb_magic))
+ return __this_address;
+
+ if (!xfs_has_reflink(mp))
+ return __this_address;
+ fa = xfs_btree_fsblock_v5hdr_verify(bp, XFS_RMAP_OWN_UNKNOWN);
+ if (fa)
+ return fa;
+ level = be16_to_cpu(block->bb_level);
+ if (level > mp->m_rtrefc_maxlevels)
+ return __this_address;
+
+ return xfs_btree_fsblock_verify(bp, mp->m_rtrefc_mxr[level != 0]);
+}
+
+static void
+xfs_rtrefcountbt_read_verify(
+ struct xfs_buf *bp)
+{
+ xfs_failaddr_t fa;
+
+ if (!xfs_btree_fsblock_verify_crc(bp))
+ xfs_verifier_error(bp, -EFSBADCRC, __this_address);
+ else {
+ fa = xfs_rtrefcountbt_verify(bp);
+ if (fa)
+ xfs_verifier_error(bp, -EFSCORRUPTED, fa);
+ }
+
+ if (bp->b_error)
+ trace_xfs_btree_corrupt(bp, _RET_IP_);
+}
+
+static void
+xfs_rtrefcountbt_write_verify(
+ struct xfs_buf *bp)
+{
+ xfs_failaddr_t fa;
+
+ fa = xfs_rtrefcountbt_verify(bp);
+ if (fa) {
+ trace_xfs_btree_corrupt(bp, _RET_IP_);
+ xfs_verifier_error(bp, -EFSCORRUPTED, fa);
+ return;
+ }
+ xfs_btree_fsblock_calc_crc(bp);
+
+}
+
+const struct xfs_buf_ops xfs_rtrefcountbt_buf_ops = {
+ .name = "xfs_rtrefcountbt",
+ .magic = { 0, cpu_to_be32(XFS_RTREFC_CRC_MAGIC) },
+ .verify_read = xfs_rtrefcountbt_read_verify,
+ .verify_write = xfs_rtrefcountbt_write_verify,
+ .verify_struct = xfs_rtrefcountbt_verify,
+};
+
+const struct xfs_btree_ops xfs_rtrefcountbt_ops = {
+ .name = "rtrefcount",
+ .type = XFS_BTREE_TYPE_INODE,
+ .geom_flags = XFS_BTGEO_IROOT_RECORDS,
+
+ .rec_len = sizeof(struct xfs_refcount_rec),
+ .key_len = sizeof(struct xfs_refcount_key),
+ .ptr_len = XFS_BTREE_LONG_PTR_LEN,
+
+ .lru_refs = XFS_REFC_BTREE_REF,
+ .statoff = XFS_STATS_CALC_INDEX(xs_rtrefcbt_2),
+
+ .dup_cursor = xfs_rtrefcountbt_dup_cursor,
+ .buf_ops = &xfs_rtrefcountbt_buf_ops,
+};
+
+/* Allocate a new rt refcount btree cursor. */
+struct xfs_btree_cur *
+xfs_rtrefcountbt_init_cursor(
+ struct xfs_mount *mp,
+ struct xfs_trans *tp,
+ struct xfs_rtgroup *rtg,
+ struct xfs_inode *ip)
+{
+ struct xfs_btree_cur *cur;
+ struct xfs_ifork *ifp = xfs_ifork_ptr(ip, XFS_DATA_FORK);
+
+ xfs_assert_ilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL);
+
+ cur = xfs_btree_alloc_cursor(mp, tp, &xfs_rtrefcountbt_ops,
+ mp->m_rtrefc_maxlevels, xfs_rtrefcountbt_cur_cache);
+
+ cur->bc_ino.ip = ip;
+ cur->bc_refc.nr_ops = 0;
+ cur->bc_refc.shape_changes = 0;
+ cur->bc_group = xfs_group_hold(&rtg->rtg_group);
+ cur->bc_nlevels = be16_to_cpu(ifp->if_broot->bb_level) + 1;
+ cur->bc_ino.forksize = xfs_inode_fork_size(ip, XFS_DATA_FORK);
+ cur->bc_ino.whichfork = XFS_DATA_FORK;
+ return cur;
+}
+
+/*
+ * Install a new rt reverse mapping btree root. Caller is responsible for
+ * invalidating and freeing the old btree blocks.
+ */
+void
+xfs_rtrefcountbt_commit_staged_btree(
+ struct xfs_btree_cur *cur,
+ struct xfs_trans *tp)
+{
+ struct xbtree_ifakeroot *ifake = cur->bc_ino.ifake;
+ struct xfs_ifork *ifp;
+ int flags = XFS_ILOG_CORE | XFS_ILOG_DBROOT;
+
+ ASSERT(cur->bc_flags & XFS_BTREE_STAGING);
+
+ /*
+ * Free any resources hanging off the real fork, then shallow-copy the
+ * staging fork's contents into the real fork to transfer everything
+ * we just built.
+ */
+ ifp = xfs_ifork_ptr(cur->bc_ino.ip, XFS_DATA_FORK);
+ xfs_idestroy_fork(ifp);
+ memcpy(ifp, ifake->if_fork, sizeof(struct xfs_ifork));
+
+ cur->bc_ino.ip->i_projid = cur->bc_group->xg_index;
+ xfs_trans_log_inode(tp, cur->bc_ino.ip, flags);
+ xfs_btree_commit_ifakeroot(cur, tp, XFS_DATA_FORK);
+}
+
+/* Calculate number of records in a realtime refcount btree block. */
+static inline unsigned int
+xfs_rtrefcountbt_block_maxrecs(
+ unsigned int blocklen,
+ bool leaf)
+{
+
+ if (leaf)
+ return blocklen / sizeof(struct xfs_refcount_rec);
+ return blocklen / (sizeof(struct xfs_refcount_key) +
+ sizeof(xfs_rtrefcount_ptr_t));
+}
+
+/*
+ * Calculate number of records in an refcount btree block.
+ */
+unsigned int
+xfs_rtrefcountbt_maxrecs(
+ struct xfs_mount *mp,
+ unsigned int blocklen,
+ bool leaf)
+{
+ blocklen -= XFS_RTREFCOUNT_BLOCK_LEN;
+ return xfs_rtrefcountbt_block_maxrecs(blocklen, leaf);
+}
+
+/* Compute the max possible height for realtime refcount btrees. */
+unsigned int
+xfs_rtrefcountbt_maxlevels_ondisk(void)
+{
+ unsigned int minrecs[2];
+ unsigned int blocklen;
+
+ blocklen = XFS_MIN_CRC_BLOCKSIZE - XFS_BTREE_LBLOCK_CRC_LEN;
+
+ minrecs[0] = xfs_rtrefcountbt_block_maxrecs(blocklen, true) / 2;
+ minrecs[1] = xfs_rtrefcountbt_block_maxrecs(blocklen, false) / 2;
+
+ /* We need at most one record for every block in an rt group. */
+ return xfs_btree_compute_maxlevels(minrecs, XFS_MAX_RGBLOCKS);
+}
+
+int __init
+xfs_rtrefcountbt_init_cur_cache(void)
+{
+ xfs_rtrefcountbt_cur_cache = kmem_cache_create("xfs_rtrefcountbt_cur",
+ xfs_btree_cur_sizeof(
+ xfs_rtrefcountbt_maxlevels_ondisk()),
+ 0, 0, NULL);
+
+ if (!xfs_rtrefcountbt_cur_cache)
+ return -ENOMEM;
+ return 0;
+}
+
+void
+xfs_rtrefcountbt_destroy_cur_cache(void)
+{
+ kmem_cache_destroy(xfs_rtrefcountbt_cur_cache);
+ xfs_rtrefcountbt_cur_cache = NULL;
+}
+
+/* Compute the maximum height of a realtime refcount btree. */
+void
+xfs_rtrefcountbt_compute_maxlevels(
+ struct xfs_mount *mp)
+{
+ unsigned int d_maxlevels, r_maxlevels;
+
+ if (!xfs_has_rtreflink(mp)) {
+ mp->m_rtrefc_maxlevels = 0;
+ return;
+ }
+
+ /*
+ * The realtime refcountbt lives on the data device, which means that
+ * its maximum height is constrained by the size of the data device and
+ * the height required to store one refcount record for each rtextent
+ * in an rt group.
+ */
+ d_maxlevels = xfs_btree_space_to_height(mp->m_rtrefc_mnr,
+ mp->m_sb.sb_dblocks);
+ r_maxlevels = xfs_btree_compute_maxlevels(mp->m_rtrefc_mnr,
+ mp->m_sb.sb_rgextents);
+
+ /* Add one level to handle the inode root level. */
+ mp->m_rtrefc_maxlevels = min(d_maxlevels, r_maxlevels) + 1;
+}
--- /dev/null
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2021-2024 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#ifndef __XFS_RTREFCOUNT_BTREE_H__
+#define __XFS_RTREFCOUNT_BTREE_H__
+
+struct xfs_buf;
+struct xfs_btree_cur;
+struct xfs_mount;
+struct xbtree_ifakeroot;
+struct xfs_rtgroup;
+
+/* refcounts only exist on crc enabled filesystems */
+#define XFS_RTREFCOUNT_BLOCK_LEN XFS_BTREE_LBLOCK_CRC_LEN
+
+struct xfs_btree_cur *xfs_rtrefcountbt_init_cursor(struct xfs_mount *mp,
+ struct xfs_trans *tp, struct xfs_rtgroup *rtg,
+ struct xfs_inode *ip);
+struct xfs_btree_cur *xfs_rtrefcountbt_stage_cursor(struct xfs_mount *mp,
+ struct xfs_rtgroup *rtg, struct xfs_inode *ip,
+ struct xbtree_ifakeroot *ifake);
+void xfs_rtrefcountbt_commit_staged_btree(struct xfs_btree_cur *cur,
+ struct xfs_trans *tp);
+unsigned int xfs_rtrefcountbt_maxrecs(struct xfs_mount *mp,
+ unsigned int blocklen, bool leaf);
+void xfs_rtrefcountbt_compute_maxlevels(struct xfs_mount *mp);
+
+/*
+ * Addresses of records, keys, and pointers within an incore rtrefcountbt block.
+ *
+ * (note that some of these may appear unused, but they are used in userspace)
+ */
+static inline struct xfs_refcount_rec *
+xfs_rtrefcount_rec_addr(
+ struct xfs_btree_block *block,
+ unsigned int index)
+{
+ return (struct xfs_refcount_rec *)
+ ((char *)block + XFS_RTREFCOUNT_BLOCK_LEN +
+ (index - 1) * sizeof(struct xfs_refcount_rec));
+}
+
+static inline struct xfs_refcount_key *
+xfs_rtrefcount_key_addr(
+ struct xfs_btree_block *block,
+ unsigned int index)
+{
+ return (struct xfs_refcount_key *)
+ ((char *)block + XFS_RTREFCOUNT_BLOCK_LEN +
+ (index - 1) * sizeof(struct xfs_refcount_key));
+}
+
+static inline xfs_rtrefcount_ptr_t *
+xfs_rtrefcount_ptr_addr(
+ struct xfs_btree_block *block,
+ unsigned int index,
+ unsigned int maxrecs)
+{
+ return (xfs_rtrefcount_ptr_t *)
+ ((char *)block + XFS_RTREFCOUNT_BLOCK_LEN +
+ maxrecs * sizeof(struct xfs_refcount_key) +
+ (index - 1) * sizeof(xfs_rtrefcount_ptr_t));
+}
+
+unsigned int xfs_rtrefcountbt_maxlevels_ondisk(void);
+int __init xfs_rtrefcountbt_init_cur_cache(void);
+void xfs_rtrefcountbt_destroy_cur_cache(void);
+
+#endif /* __XFS_RTREFCOUNT_BTREE_H__ */