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-rw-r--r--fs/xfs/libxfs/xfs_btree_mem.c347
1 files changed, 347 insertions, 0 deletions
diff --git a/fs/xfs/libxfs/xfs_btree_mem.c b/fs/xfs/libxfs/xfs_btree_mem.c
new file mode 100644
index 0000000000..036061fe32
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_btree_mem.c
@@ -0,0 +1,347 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * 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_mount.h"
+#include "xfs_trans.h"
+#include "xfs_btree.h"
+#include "xfs_error.h"
+#include "xfs_buf_mem.h"
+#include "xfs_btree_mem.h"
+#include "xfs_ag.h"
+#include "xfs_buf_item.h"
+#include "xfs_trace.h"
+
+/* 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)
+{
+ ASSERT(cur->bc_ops->type == XFS_BTREE_TYPE_MEM);
+
+ cur->bc_mem.xfbtree->root = *ptr;
+ cur->bc_mem.xfbtree->nlevels += inc;
+}
+
+/* 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)
+{
+ ASSERT(cur->bc_ops->type == XFS_BTREE_TYPE_MEM);
+
+ *ptr = cur->bc_mem.xfbtree->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_ops->type == XFS_BTREE_TYPE_MEM);
+
+ ncur = xfs_btree_alloc_cursor(cur->bc_mp, cur->bc_tp, cur->bc_ops,
+ cur->bc_maxlevels, cur->bc_cache);
+ ncur->bc_flags = cur->bc_flags;
+ ncur->bc_nlevels = cur->bc_nlevels;
+ ncur->bc_mem.xfbtree = cur->bc_mem.xfbtree;
+
+ if (cur->bc_mem.pag)
+ ncur->bc_mem.pag = xfs_perag_hold(cur->bc_mem.pag);
+
+ return ncur;
+}
+
+/* Close the btree xfile and release all resources. */
+void
+xfbtree_destroy(
+ struct xfbtree *xfbt)
+{
+ xfs_buftarg_drain(xfbt->target);
+}
+
+/* Compute the number of bytes available for records. */
+static inline unsigned int
+xfbtree_rec_bytes(
+ struct xfs_mount *mp,
+ const struct xfs_btree_ops *ops)
+{
+ return XMBUF_BLOCKSIZE - XFS_BTREE_LBLOCK_CRC_LEN;
+}
+
+/* Initialize an empty leaf block as the btree root. */
+STATIC int
+xfbtree_init_leaf_block(
+ struct xfs_mount *mp,
+ struct xfbtree *xfbt,
+ const struct xfs_btree_ops *ops)
+{
+ struct xfs_buf *bp;
+ xfbno_t bno = xfbt->highest_bno++;
+ int error;
+
+ error = xfs_buf_get(xfbt->target, xfbno_to_daddr(bno), XFBNO_BBSIZE,
+ &bp);
+ if (error)
+ return error;
+
+ trace_xfbtree_create_root_buf(xfbt, bp);
+
+ bp->b_ops = ops->buf_ops;
+ xfs_btree_init_buf(mp, bp, ops, 0, 0, xfbt->owner);
+ xfs_buf_relse(bp);
+
+ xfbt->root.l = cpu_to_be64(bno);
+ return 0;
+}
+
+/*
+ * Create an in-memory btree root that can be used with the given xmbuf.
+ * Callers must set xfbt->owner.
+ */
+int
+xfbtree_init(
+ struct xfs_mount *mp,
+ struct xfbtree *xfbt,
+ struct xfs_buftarg *btp,
+ const struct xfs_btree_ops *ops)
+{
+ unsigned int blocklen = xfbtree_rec_bytes(mp, ops);
+ unsigned int keyptr_len;
+ int error;
+
+ /* Requires a long-format CRC-format btree */
+ if (!xfs_has_crc(mp)) {
+ ASSERT(xfs_has_crc(mp));
+ return -EINVAL;
+ }
+ if (ops->ptr_len != XFS_BTREE_LONG_PTR_LEN) {
+ ASSERT(ops->ptr_len == XFS_BTREE_LONG_PTR_LEN);
+ return -EINVAL;
+ }
+
+ memset(xfbt, 0, sizeof(*xfbt));
+ xfbt->target = btp;
+
+ /* Set up min/maxrecs for this btree. */
+ keyptr_len = ops->key_len + sizeof(__be64);
+ xfbt->maxrecs[0] = blocklen / ops->rec_len;
+ xfbt->maxrecs[1] = blocklen / keyptr_len;
+ xfbt->minrecs[0] = xfbt->maxrecs[0] / 2;
+ xfbt->minrecs[1] = xfbt->maxrecs[1] / 2;
+ xfbt->highest_bno = 0;
+ xfbt->nlevels = 1;
+
+ /* Initialize the empty btree. */
+ error = xfbtree_init_leaf_block(mp, xfbt, ops);
+ if (error)
+ goto err_freesp;
+
+ trace_xfbtree_init(mp, xfbt, ops);
+
+ return 0;
+
+err_freesp:
+ xfs_buftarg_drain(xfbt->target);
+ return error;
+}
+
+/* Allocate a block to our in-memory btree. */
+int
+xfbtree_alloc_block(
+ struct xfs_btree_cur *cur,
+ const union xfs_btree_ptr *start,
+ union xfs_btree_ptr *new,
+ int *stat)
+{
+ struct xfbtree *xfbt = cur->bc_mem.xfbtree;
+ xfbno_t bno = xfbt->highest_bno++;
+
+ ASSERT(cur->bc_ops->type == XFS_BTREE_TYPE_MEM);
+
+ trace_xfbtree_alloc_block(xfbt, cur, bno);
+
+ /* Fail if the block address exceeds the maximum for the buftarg. */
+ if (!xfbtree_verify_bno(xfbt, bno)) {
+ ASSERT(xfbtree_verify_bno(xfbt, bno));
+ *stat = 0;
+ return 0;
+ }
+
+ new->l = cpu_to_be64(bno);
+ *stat = 1;
+ return 0;
+}
+
+/* Free a block from our in-memory btree. */
+int
+xfbtree_free_block(
+ struct xfs_btree_cur *cur,
+ struct xfs_buf *bp)
+{
+ struct xfbtree *xfbt = cur->bc_mem.xfbtree;
+ xfs_daddr_t daddr = xfs_buf_daddr(bp);
+ xfbno_t bno = xfs_daddr_to_xfbno(daddr);
+
+ ASSERT(cur->bc_ops->type == XFS_BTREE_TYPE_MEM);
+
+ trace_xfbtree_free_block(xfbt, cur, bno);
+
+ if (bno + 1 == xfbt->highest_bno)
+ xfbt->highest_bno--;
+
+ return 0;
+}
+
+/* Return the minimum number of records for a btree block. */
+int
+xfbtree_get_minrecs(
+ struct xfs_btree_cur *cur,
+ int level)
+{
+ struct xfbtree *xfbt = cur->bc_mem.xfbtree;
+
+ return xfbt->minrecs[level != 0];
+}
+
+/* Return the maximum number of records for a btree block. */
+int
+xfbtree_get_maxrecs(
+ struct xfs_btree_cur *cur,
+ int level)
+{
+ struct xfbtree *xfbt = cur->bc_mem.xfbtree;
+
+ return xfbt->maxrecs[level != 0];
+}
+
+/* If this log item is a buffer item that came from the xfbtree, return it. */
+static inline struct xfs_buf *
+xfbtree_buf_match(
+ struct xfbtree *xfbt,
+ const struct xfs_log_item *lip)
+{
+ const struct xfs_buf_log_item *bli;
+ struct xfs_buf *bp;
+
+ if (lip->li_type != XFS_LI_BUF)
+ return NULL;
+
+ bli = container_of(lip, struct xfs_buf_log_item, bli_item);
+ bp = bli->bli_buf;
+ if (bp->b_target != xfbt->target)
+ return NULL;
+
+ return bp;
+}
+
+/*
+ * Commit changes to the incore btree immediately by writing all dirty xfbtree
+ * buffers to the backing xfile. This detaches all xfbtree buffers from the
+ * transaction, even on failure. The buffer locks are dropped between the
+ * delwri queue and submit, so the caller must synchronize btree access.
+ *
+ * Normally we'd let the buffers commit with the transaction and get written to
+ * the xfile via the log, but online repair stages ephemeral btrees in memory
+ * and uses the btree_staging functions to write new btrees to disk atomically.
+ * The in-memory btree (and its backing store) are discarded at the end of the
+ * repair phase, which means that xfbtree buffers cannot commit with the rest
+ * of a transaction.
+ *
+ * In other words, online repair only needs the transaction to collect buffer
+ * pointers and to avoid buffer deadlocks, not to guarantee consistency of
+ * updates.
+ */
+int
+xfbtree_trans_commit(
+ struct xfbtree *xfbt,
+ struct xfs_trans *tp)
+{
+ struct xfs_log_item *lip, *n;
+ bool tp_dirty = false;
+ int error = 0;
+
+ /*
+ * For each xfbtree buffer attached to the transaction, write the dirty
+ * buffers to the xfile and release them.
+ */
+ list_for_each_entry_safe(lip, n, &tp->t_items, li_trans) {
+ struct xfs_buf *bp = xfbtree_buf_match(xfbt, lip);
+
+ if (!bp) {
+ if (test_bit(XFS_LI_DIRTY, &lip->li_flags))
+ tp_dirty |= true;
+ continue;
+ }
+
+ trace_xfbtree_trans_commit_buf(xfbt, bp);
+
+ xmbuf_trans_bdetach(tp, bp);
+
+ /*
+ * If the buffer fails verification, note the failure but
+ * continue walking the transaction items so that we remove all
+ * ephemeral btree buffers.
+ */
+ if (!error)
+ error = xmbuf_finalize(bp);
+
+ xfs_buf_relse(bp);
+ }
+
+ /*
+ * Reset the transaction's dirty flag to reflect the dirty state of the
+ * log items that are still attached.
+ */
+ tp->t_flags = (tp->t_flags & ~XFS_TRANS_DIRTY) |
+ (tp_dirty ? XFS_TRANS_DIRTY : 0);
+
+ return error;
+}
+
+/*
+ * Cancel changes to the incore btree by detaching all the xfbtree buffers.
+ * Changes are not undone, so callers must not access the btree ever again.
+ */
+void
+xfbtree_trans_cancel(
+ struct xfbtree *xfbt,
+ struct xfs_trans *tp)
+{
+ struct xfs_log_item *lip, *n;
+ bool tp_dirty = false;
+
+ list_for_each_entry_safe(lip, n, &tp->t_items, li_trans) {
+ struct xfs_buf *bp = xfbtree_buf_match(xfbt, lip);
+
+ if (!bp) {
+ if (test_bit(XFS_LI_DIRTY, &lip->li_flags))
+ tp_dirty |= true;
+ continue;
+ }
+
+ trace_xfbtree_trans_cancel_buf(xfbt, bp);
+
+ xmbuf_trans_bdetach(tp, bp);
+ xfs_buf_relse(bp);
+ }
+
+ /*
+ * Reset the transaction's dirty flag to reflect the dirty state of the
+ * log items that are still attached.
+ */
+ tp->t_flags = (tp->t_flags & ~XFS_TRANS_DIRTY) |
+ (tp_dirty ? XFS_TRANS_DIRTY : 0);
+}