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2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/drivers/md/dm-thin-metadata.c
..
..
@@ -701,6 +701,15 @@
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 		goto bad_cleanup_data_sm;
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 	}
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+	/*
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+	 * For pool metadata opening process, root setting is redundant
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+	 * because it will be set again in __begin_transaction(). But dm
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+	 * pool aborting process really needs to get last transaction's
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+	 * root to avoid accessing broken btree.
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+	 */
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+	pmd->root = le64_to_cpu(disk_super->data_mapping_root);
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+	pmd->details_root = le64_to_cpu(disk_super->device_details_root);
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+
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 	__setup_btree_details(pmd);
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 	dm_bm_unlock(sblock);
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..
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@@ -753,13 +762,15 @@
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 	return r;
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 }
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764
 
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-static void __destroy_persistent_data_objects(struct dm_pool_metadata *pmd)
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+static void __destroy_persistent_data_objects(struct dm_pool_metadata *pmd,
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+					      bool destroy_bm)
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 {
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 	dm_sm_destroy(pmd->data_sm);
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 	dm_sm_destroy(pmd->metadata_sm);
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 	dm_tm_destroy(pmd->nb_tm);
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 	dm_tm_destroy(pmd->tm);
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-	dm_block_manager_destroy(pmd->bm);
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+	if (destroy_bm)
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+		dm_block_manager_destroy(pmd->bm);
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 }
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 static int __begin_transaction(struct dm_pool_metadata *pmd)
..
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@@ -966,7 +977,7 @@
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 	}
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 	pmd_write_unlock(pmd);
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 	if (!pmd->fail_io)
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-		__destroy_persistent_data_objects(pmd);
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+		__destroy_persistent_data_objects(pmd, true);
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 	kfree(pmd);
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 	return 0;
..
..
@@ -1873,19 +1884,52 @@
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 int dm_pool_abort_metadata(struct dm_pool_metadata *pmd)
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 {
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 	int r = -EINVAL;
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+	struct dm_block_manager *old_bm = NULL, *new_bm = NULL;
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+
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+	/* fail_io is double-checked with pmd->root_lock held below */
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+	if (unlikely(pmd->fail_io))
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+		return r;
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+
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+	/*
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+	 * Replacement block manager (new_bm) is created and old_bm destroyed outside of
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+	 * pmd root_lock to avoid ABBA deadlock that would result (due to life-cycle of
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+	 * shrinker associated with the block manager's bufio client vs pmd root_lock).
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+	 * - must take shrinker_rwsem without holding pmd->root_lock
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+	 */
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+	new_bm = dm_block_manager_create(pmd->bdev, THIN_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
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+					 THIN_MAX_CONCURRENT_LOCKS);
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 	pmd_write_lock(pmd);
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-	if (pmd->fail_io)
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+	if (pmd->fail_io) {
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+		pmd_write_unlock(pmd);
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 		goto out;
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+	}
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 	__set_abort_with_changes_flags(pmd);
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-	__destroy_persistent_data_objects(pmd);
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-	r = __create_persistent_data_objects(pmd, false);
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+	__destroy_persistent_data_objects(pmd, false);
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+	old_bm = pmd->bm;
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+	if (IS_ERR(new_bm)) {
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+		DMERR("could not create block manager during abort");
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+		pmd->bm = NULL;
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+		r = PTR_ERR(new_bm);
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+		goto out_unlock;
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+	}
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+
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+	pmd->bm = new_bm;
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+	r = __open_or_format_metadata(pmd, false);
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+	if (r) {
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+		pmd->bm = NULL;
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+		goto out_unlock;
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+	}
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+	new_bm = NULL;
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+out_unlock:
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 	if (r)
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 		pmd->fail_io = true;
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-
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-out:
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 	pmd_write_unlock(pmd);
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+	dm_block_manager_destroy(old_bm);
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+out:
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+	if (new_bm && !IS_ERR(new_bm))
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+		dm_block_manager_destroy(new_bm);
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 	return r;
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 }