xfs: support in-memory btrees

Adapt the generic btree cursor code to be able to create a btree whose
buffers come from a (presumably in-memory) buftarg with a header block
that's specific to in-memory btrees.  We'll connect this to other parts
of online scrub in the next patches.

Note that in-memory btrees always have a block size matching the system
memory page size for efficiency reasons.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>

1 files changed, 352 insertions, 0 deletions

diff --git a/fs/xfs/scrub/xfbtree.c b/fs/xfs/scrub/xfbtree.c
new file mode 100644
index 000000000000..80f9ab4fec07
--- /dev/null
+++ b/fs/xfs/scrub/xfbtree.c
@@ -0,0 +1,352 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2022 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_mount.h"
+#include "xfs_trans.h"
+#include "xfs_btree.h"
+#include "xfs_error.h"
+#include "xfs_btree_mem.h"
+#include "xfs_ag.h"
+#include "scrub/xfile.h"
+#include "scrub/xfbtree.h"
+
+/* btree ops functions for in-memory btrees. */
+
+static xfs_failaddr_t
+xfs_btree_mem_head_verify(
+	struct xfs_buf			*bp)
+{
+	struct xfs_btree_mem_head	*mhead = bp->b_addr;
+	struct xfs_mount		*mp = bp->b_mount;
+
+	if (!xfs_verify_magic(bp, mhead->mh_magic))
+		return __this_address;
+	if (be32_to_cpu(mhead->mh_nlevels) == 0)
+		return __this_address;
+	if (!uuid_equal(&mhead->mh_uuid, &mp->m_sb.sb_meta_uuid))
+		return __this_address;
+
+	return NULL;
+}
+
+static void
+xfs_btree_mem_head_read_verify(
+	struct xfs_buf		*bp)
+{
+	xfs_failaddr_t		fa = xfs_btree_mem_head_verify(bp);
+
+	if (fa)
+		xfs_verifier_error(bp, -EFSCORRUPTED, fa);
+}
+
+static void
+xfs_btree_mem_head_write_verify(
+	struct xfs_buf		*bp)
+{
+	xfs_failaddr_t		fa = xfs_btree_mem_head_verify(bp);
+
+	if (fa)
+		xfs_verifier_error(bp, -EFSCORRUPTED, fa);
+}
+
+static const struct xfs_buf_ops xfs_btree_mem_head_buf_ops = {
+	.name			= "xfs_btree_mem_head",
+	.magic			= { cpu_to_be32(XFS_BTREE_MEM_HEAD_MAGIC),
+				    cpu_to_be32(XFS_BTREE_MEM_HEAD_MAGIC) },
+	.verify_read		= xfs_btree_mem_head_read_verify,
+	.verify_write		= xfs_btree_mem_head_write_verify,
+	.verify_struct		= xfs_btree_mem_head_verify,
+};
+
+/* Initialize the header block for an in-memory btree. */
+static inline void
+xfs_btree_mem_head_init(
+	struct xfs_buf			*head_bp,
+	unsigned long long		owner,
+	xfileoff_t			leaf_xfoff)
+{
+	struct xfs_btree_mem_head	*mhead = head_bp->b_addr;
+	struct xfs_mount		*mp = head_bp->b_mount;
+
+	mhead->mh_magic = cpu_to_be32(XFS_BTREE_MEM_HEAD_MAGIC);
+	mhead->mh_nlevels = cpu_to_be32(1);
+	mhead->mh_owner = cpu_to_be64(owner);
+	mhead->mh_root = cpu_to_be64(leaf_xfoff);
+	uuid_copy(&mhead->mh_uuid, &mp->m_sb.sb_meta_uuid);
+
+	head_bp->b_ops = &xfs_btree_mem_head_buf_ops;
+}
+
+/* Return tree height from the in-memory btree head. */
+unsigned int
+xfs_btree_mem_head_nlevels(
+	struct xfs_buf			*head_bp)
+{
+	struct xfs_btree_mem_head	*mhead = head_bp->b_addr;
+
+	return be32_to_cpu(mhead->mh_nlevels);
+}
+
+/* Extract the buftarg target for this xfile btree. */
+struct xfs_buftarg *
+xfbtree_target(struct xfbtree *xfbtree)
+{
+	return xfbtree->target;
+}
+
+/* Is this daddr (sector offset) contained within the buffer target? */
+static inline bool
+xfbtree_verify_buftarg_xfileoff(
+	struct xfs_buftarg	*btp,
+	xfileoff_t		xfoff)
+{
+	xfs_daddr_t		xfoff_daddr = xfo_to_daddr(xfoff);
+
+	return xfs_buftarg_verify_daddr(btp, xfoff_daddr);
+}
+
+/* Is this btree xfile offset contained within the xfile? */
+bool
+xfbtree_verify_xfileoff(
+	struct xfs_btree_cur	*cur,
+	unsigned long long	xfoff)
+{
+	struct xfs_buftarg	*btp = xfbtree_target(cur->bc_mem.xfbtree);
+
+	return xfbtree_verify_buftarg_xfileoff(btp, xfoff);
+}
+
+/* Check if a btree pointer is reasonable. */
+int
+xfbtree_check_ptr(
+	struct xfs_btree_cur		*cur,
+	const union xfs_btree_ptr	*ptr,
+	int				index,
+	int				level)
+{
+	xfileoff_t			bt_xfoff;
+	xfs_failaddr_t			fa = NULL;
+
+	ASSERT(cur->bc_flags & XFS_BTREE_IN_MEMORY);
+
+	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
+		bt_xfoff = be64_to_cpu(ptr->l);
+	else
+		bt_xfoff = be32_to_cpu(ptr->s);
+
+	if (!xfbtree_verify_xfileoff(cur, bt_xfoff))
+		fa = __this_address;
+
+	if (fa) {
+		xfs_err(cur->bc_mp,
+"In-memory: Corrupt btree %d flags 0x%x pointer at level %d index %d fa %pS.",
+				cur->bc_btnum, cur->bc_flags, level, index,
+				fa);
+		return -EFSCORRUPTED;
+	}
+	return 0;
+}
+
+/* Convert a btree pointer to a daddr */
+xfs_daddr_t
+xfbtree_ptr_to_daddr(
+	struct xfs_btree_cur		*cur,
+	const union xfs_btree_ptr	*ptr)
+{
+	xfileoff_t			bt_xfoff;
+
+	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
+		bt_xfoff = be64_to_cpu(ptr->l);
+	else
+		bt_xfoff = be32_to_cpu(ptr->s);
+	return xfo_to_daddr(bt_xfoff);
+}
+
+/* Set the pointer to point to this buffer. */
+void
+xfbtree_buf_to_ptr(
+	struct xfs_btree_cur	*cur,
+	struct xfs_buf		*bp,
+	union xfs_btree_ptr	*ptr)
+{
+	xfileoff_t		xfoff = xfs_daddr_to_xfo(xfs_buf_daddr(bp));
+
+	if (cur->bc_flags & XFS_BTREE_LONG_PTRS)
+		ptr->l = cpu_to_be64(xfoff);
+	else
+		ptr->s = cpu_to_be32(xfoff);
+}
+
+/* Return the in-memory btree block size, in units of 512 bytes. */
+unsigned int xfbtree_bbsize(void)
+{
+	return xfo_to_daddr(1);
+}
+
+/* Set the root of an in-memory btree. */
+void
+xfbtree_set_root(
+	struct xfs_btree_cur		*cur,
+	const union xfs_btree_ptr	*ptr,
+	int				inc)
+{
+	struct xfs_buf			*head_bp = cur->bc_mem.head_bp;
+	struct xfs_btree_mem_head	*mhead = head_bp->b_addr;
+
+	ASSERT(cur->bc_flags & XFS_BTREE_IN_MEMORY);
+
+	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
+		mhead->mh_root = ptr->l;
+	} else {
+		uint32_t		root = be32_to_cpu(ptr->s);
+
+		mhead->mh_root = cpu_to_be64(root);
+	}
+	be32_add_cpu(&mhead->mh_nlevels, inc);
+	xfs_trans_log_buf(cur->bc_tp, head_bp, 0, sizeof(*mhead) - 1);
+}
+
+/* Initialize a pointer from the in-memory btree header. */
+void
+xfbtree_init_ptr_from_cur(
+	struct xfs_btree_cur		*cur,
+	union xfs_btree_ptr		*ptr)
+{
+	struct xfs_buf			*head_bp = cur->bc_mem.head_bp;
+	struct xfs_btree_mem_head	*mhead = head_bp->b_addr;
+
+	ASSERT(cur->bc_flags & XFS_BTREE_IN_MEMORY);
+
+	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
+		ptr->l = mhead->mh_root;
+	} else {
+		uint64_t		root = be64_to_cpu(mhead->mh_root);
+
+		ptr->s = cpu_to_be32(root);
+	}
+}
+
+/* Duplicate an in-memory btree cursor. */
+struct xfs_btree_cur *
+xfbtree_dup_cursor(
+	struct xfs_btree_cur		*cur)
+{
+	struct xfs_btree_cur		*ncur;
+
+	ASSERT(cur->bc_flags & XFS_BTREE_IN_MEMORY);
+
+	ncur = xfs_btree_alloc_cursor(cur->bc_mp, cur->bc_tp, cur->bc_btnum,
+			cur->bc_maxlevels, cur->bc_cache);
+	ncur->bc_flags = cur->bc_flags;
+	ncur->bc_nlevels = cur->bc_nlevels;
+	ncur->bc_statoff = cur->bc_statoff;
+	ncur->bc_ops = cur->bc_ops;
+	memcpy(&ncur->bc_mem, &cur->bc_mem, sizeof(cur->bc_mem));
+
+	if (cur->bc_mem.pag)
+		ncur->bc_mem.pag = xfs_perag_bump(cur->bc_mem.pag);
+
+	return ncur;
+}
+
+/* Check the owner of an in-memory btree block. */
+xfs_failaddr_t
+xfbtree_check_block_owner(
+	struct xfs_btree_cur	*cur,
+	struct xfs_btree_block	*block)
+{
+	struct xfbtree		*xfbt = cur->bc_mem.xfbtree;
+
+	if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
+		if (be64_to_cpu(block->bb_u.l.bb_owner) != xfbt->owner)
+			return __this_address;
+
+		return NULL;
+	}
+
+	if (be32_to_cpu(block->bb_u.s.bb_owner) != xfbt->owner)
+		return __this_address;
+
+	return NULL;
+}
+
+/* Return the owner of this in-memory btree. */
+unsigned long long
+xfbtree_owner(
+	struct xfs_btree_cur	*cur)
+{
+	return cur->bc_mem.xfbtree->owner;
+}
+
+/* Return the xfile offset (in blocks) of a btree buffer. */
+unsigned long long
+xfbtree_buf_to_xfoff(
+	struct xfs_btree_cur	*cur,
+	struct xfs_buf		*bp)
+{
+	ASSERT(cur->bc_flags & XFS_BTREE_IN_MEMORY);
+
+	return xfs_daddr_to_xfo(xfs_buf_daddr(bp));
+}
+
+/* Verify a long-format btree block. */
+xfs_failaddr_t
+xfbtree_lblock_verify(
+	struct xfs_buf		*bp,
+	unsigned int		max_recs)
+{
+	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
+	struct xfs_buftarg	*btp = bp->b_target;
+
+	/* numrecs verification */
+	if (be16_to_cpu(block->bb_numrecs) > max_recs)
+		return __this_address;
+
+	/* sibling pointer verification */
+	if (block->bb_u.l.bb_leftsib != cpu_to_be64(NULLFSBLOCK) &&
+	    !xfbtree_verify_buftarg_xfileoff(btp,
+				be64_to_cpu(block->bb_u.l.bb_leftsib)))
+		return __this_address;
+
+	if (block->bb_u.l.bb_rightsib != cpu_to_be64(NULLFSBLOCK) &&
+	    !xfbtree_verify_buftarg_xfileoff(btp,
+				be64_to_cpu(block->bb_u.l.bb_rightsib)))
+		return __this_address;
+
+	return NULL;
+}
+
+/* Verify a short-format btree block. */
+xfs_failaddr_t
+xfbtree_sblock_verify(
+	struct xfs_buf		*bp,
+	unsigned int		max_recs)
+{
+	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
+	struct xfs_buftarg	*btp = bp->b_target;
+
+	/* numrecs verification */
+	if (be16_to_cpu(block->bb_numrecs) > max_recs)
+		return __this_address;
+
+	/* sibling pointer verification */
+	if (block->bb_u.s.bb_leftsib != cpu_to_be32(NULLAGBLOCK) &&
+	    !xfbtree_verify_buftarg_xfileoff(btp,
+				be32_to_cpu(block->bb_u.s.bb_leftsib)))
+		return __this_address;
+
+	if (block->bb_u.s.bb_rightsib != cpu_to_be32(NULLAGBLOCK) &&
+	    !xfbtree_verify_buftarg_xfileoff(btp,
+				be32_to_cpu(block->bb_u.s.bb_rightsib)))
+		return __this_address;
+
+	return NULL;
+}