xfs: connect in-memory btrees to xfilesin-memory-btrees_2022-10-14

Add to our stubbed-out in-memory btrees the ability to connect them with
an actual in-memory backing file (aka xfiles) and the necessary pieces
to track free space in the xfile and flush dirty xfbtree buffers on
demand, which we'll need for online repair.

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

1 files changed, 42 insertions, 0 deletions

diff --git a/fs/xfs/xfs_trans_buf.c b/fs/xfs/xfs_trans_buf.c
index 6549e50d852c..e28ab74af4f0 100644
--- a/fs/xfs/xfs_trans_buf.c
+++ b/fs/xfs/xfs_trans_buf.c
@@ -393,6 +393,48 @@ xfs_trans_brelse(
 }
 
 /*
+ * Forcibly detach a buffer previously joined to the transaction.  The caller
+ * will retain its locked reference to the buffer after this function returns.
+ * The buffer must be completely clean and must not be held to the transaction.
+ */
+void
+xfs_trans_bdetach(
+	struct xfs_trans	*tp,
+	struct xfs_buf		*bp)
+{
+	struct xfs_buf_log_item	*bip = bp->b_log_item;
+
+	ASSERT(tp != NULL);
+	ASSERT(bp->b_transp == tp);
+	ASSERT(bip->bli_item.li_type == XFS_LI_BUF);
+	ASSERT(atomic_read(&bip->bli_refcount) > 0);
+
+	trace_xfs_trans_bdetach(bip);
+
+	/*
+	 * Erase all recursion count, since we're removing this buffer from the
+	 * transaction.
+	 */
+	bip->bli_recur = 0;
+
+	/*
+	 * The buffer must be completely clean.  Specifically, it had better
+	 * not be dirty, stale, logged, ordered, or held to the transaction.
+	 */
+	ASSERT(!test_bit(XFS_LI_DIRTY, &bip->bli_item.li_flags));
+	ASSERT(!(bip->bli_flags & XFS_BLI_DIRTY));
+	ASSERT(!(bip->bli_flags & XFS_BLI_HOLD));
+	ASSERT(!(bip->bli_flags & XFS_BLI_LOGGED));
+	ASSERT(!(bip->bli_flags & XFS_BLI_ORDERED));
+	ASSERT(!(bip->bli_flags & XFS_BLI_STALE));
+
+	/* Unlink the log item from the transaction and drop the log item. */
+	xfs_trans_del_item(&bip->bli_item);
+	xfs_buf_item_put(bip);
+	bp->b_transp = NULL;
+}
+
+/*
  * Mark the buffer as not needing to be unlocked when the buf item's
  * iop_committing() routine is called.  The buffer must already be locked
  * and associated with the given transaction.