Merge branch 'dynamic_sg' into rdma.git for-next

From Maor Gottlieb says:

====================
This series extends __sg_alloc_table_from_pages to allow chaining of new
pages to an already initialized SG table.

This allows for drivers to utilize the optimization of merging contiguous
pages without a need to pre allocate all the pages and hold them in a very
large temporary buffer prior to the call to SG table initialization.

The last patch changes the Infiniband core to use the new API. It removes
duplicate functionality from the code and benefits from the optimization
of allocating dynamic SG table from pages.

In huge pages system of 2MB page size, without this change, the SG table
would contain x512 SG entries.
====================

* branch 'dynamic_sg':
  RDMA/umem: Move to allocate SG table from pages
  lib/scatterlist: Add support in dynamic allocation of SG table from pages
  tools/testing/scatterlist: Show errors in human readable form
  tools/testing/scatterlist: Rejuvenate bit-rotten test

1 files changed, 44 insertions, 2 deletions

diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index db93909b25e0..e4a1c6afe35d 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -599,6 +599,37 @@ static void btrfs_rm_dev_replace_unblocked(struct btrfs_fs_info *fs_info)
 	wake_up(&fs_info->dev_replace.replace_wait);
 }
 
+/*
+ * When finishing the device replace, before swapping the source device with the
+ * target device we must update the chunk allocation state in the target device,
+ * as it is empty because replace works by directly copying the chunks and not
+ * through the normal chunk allocation path.
+ */
+static int btrfs_set_target_alloc_state(struct btrfs_device *srcdev,
+					struct btrfs_device *tgtdev)
+{
+	struct extent_state *cached_state = NULL;
+	u64 start = 0;
+	u64 found_start;
+	u64 found_end;
+	int ret = 0;
+
+	lockdep_assert_held(&srcdev->fs_info->chunk_mutex);
+
+	while (!find_first_extent_bit(&srcdev->alloc_state, start,
+				      &found_start, &found_end,
+				      CHUNK_ALLOCATED, &cached_state)) {
+		ret = set_extent_bits(&tgtdev->alloc_state, found_start,
+				      found_end, CHUNK_ALLOCATED);
+		if (ret)
+			break;
+		start = found_end + 1;
+	}
+
+	free_extent_state(cached_state);
+	return ret;
+}
+
 static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
 				       int scrub_ret)
 {
@@ -673,8 +704,14 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
 	dev_replace->time_stopped = ktime_get_real_seconds();
 	dev_replace->item_needs_writeback = 1;
 
-	/* replace old device with new one in mapping tree */
+	/*
+	 * Update allocation state in the new device and replace the old device
+	 * with the new one in the mapping tree.
+	 */
 	if (!scrub_ret) {
+		scrub_ret = btrfs_set_target_alloc_state(src_device, tgt_device);
+		if (scrub_ret)
+			goto error;
 		btrfs_dev_replace_update_device_in_mapping_tree(fs_info,
 								src_device,
 								tgt_device);
@@ -685,6 +722,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
 				 btrfs_dev_name(src_device),
 				 src_device->devid,
 				 rcu_str_deref(tgt_device->name), scrub_ret);
+error:
 		up_write(&dev_replace->rwsem);
 		mutex_unlock(&fs_info->chunk_mutex);
 		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
@@ -745,7 +783,9 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
 	/* replace the sysfs entry */
 	btrfs_sysfs_remove_devices_dir(fs_info->fs_devices, src_device);
 	btrfs_sysfs_update_devid(tgt_device);
-	btrfs_rm_dev_replace_free_srcdev(src_device);
+	if (test_bit(BTRFS_DEV_STATE_WRITEABLE, &src_device->dev_state))
+		btrfs_scratch_superblocks(fs_info, src_device->bdev,
+					  src_device->name->str);
 
 	/* write back the superblocks */
 	trans = btrfs_start_transaction(root, 0);
@@ -754,6 +794,8 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
 
 	mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
 
+	btrfs_rm_dev_replace_free_srcdev(src_device);
+
 	return 0;
 }