Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index 20b0776..4c68a7b 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -202,6 +202,13 @@
 	bool fail_io:1;
 
 	/*
+	 * Set once a thin-pool has been accessed through one of the interfaces
+	 * that imply the pool is in-service (e.g. thin devices created/deleted,
+	 * thin-pool message, metadata snapshots, etc).
+	 */
+	bool in_service:1;
+
+	/*
 	 * Reading the space map roots can fail, so we read it into these
 	 * buffers before the superblock is locked and updated.
 	 */
@@ -367,6 +374,32 @@
 
 /*----------------------------------------------------------------*/
 
+/*
+ * Variant that is used for in-core only changes or code that
+ * shouldn't put the pool in service on its own (e.g. commit).
+ */
+static inline void __pmd_write_lock(struct dm_pool_metadata *pmd)
+	__acquires(pmd->root_lock)
+{
+	down_write(&pmd->root_lock);
+}
+#define pmd_write_lock_in_core(pmd) __pmd_write_lock((pmd))
+
+static inline void pmd_write_lock(struct dm_pool_metadata *pmd)
+{
+	__pmd_write_lock(pmd);
+	if (unlikely(!pmd->in_service))
+		pmd->in_service = true;
+}
+
+static inline void pmd_write_unlock(struct dm_pool_metadata *pmd)
+	__releases(pmd->root_lock)
+{
+	up_write(&pmd->root_lock);
+}
+
+/*----------------------------------------------------------------*/
+
 static int superblock_lock_zero(struct dm_pool_metadata *pmd,
 				struct dm_block **sblock)
 {
@@ -790,6 +823,9 @@
 	 */
 	BUILD_BUG_ON(sizeof(struct thin_disk_superblock) > 512);
 
+	if (unlikely(!pmd->in_service))
+		return 0;
+
 	r = __write_changed_details(pmd);
 	if (r < 0)
 		return r;
@@ -853,6 +889,7 @@
 	pmd->time = 0;
 	INIT_LIST_HEAD(&pmd->thin_devices);
 	pmd->fail_io = false;
+	pmd->in_service = false;
 	pmd->bdev = bdev;
 	pmd->data_block_size = data_block_size;
 
@@ -903,7 +940,6 @@
 			DMWARN("%s: __commit_transaction() failed, error = %d",
 			       __func__, r);
 	}
-
 	if (!pmd->fail_io)
 		__destroy_persistent_data_objects(pmd);
 
@@ -1032,10 +1068,10 @@
 {
 	int r = -EINVAL;
 
-	down_write(&pmd->root_lock);
+	pmd_write_lock(pmd);
 	if (!pmd->fail_io)
 		r = __create_thin(pmd, dev);
-	up_write(&pmd->root_lock);
+	pmd_write_unlock(pmd);
 
 	return r;
 }
@@ -1123,10 +1159,10 @@
 {
 	int r = -EINVAL;
 
-	down_write(&pmd->root_lock);
+	pmd_write_lock(pmd);
 	if (!pmd->fail_io)
 		r = __create_snap(pmd, dev, origin);
-	up_write(&pmd->root_lock);
+	pmd_write_unlock(pmd);
 
 	return r;
 }
@@ -1166,10 +1202,10 @@
 {
 	int r = -EINVAL;
 
-	down_write(&pmd->root_lock);
+	pmd_write_lock(pmd);
 	if (!pmd->fail_io)
 		r = __delete_device(pmd, dev);
-	up_write(&pmd->root_lock);
+	pmd_write_unlock(pmd);
 
 	return r;
 }
@@ -1180,7 +1216,7 @@
 {
 	int r = -EINVAL;
 
-	down_write(&pmd->root_lock);
+	pmd_write_lock(pmd);
 
 	if (pmd->fail_io)
 		goto out;
@@ -1194,7 +1230,7 @@
 	r = 0;
 
 out:
-	up_write(&pmd->root_lock);
+	pmd_write_unlock(pmd);
 
 	return r;
 }
@@ -1225,7 +1261,12 @@
 	 * We commit to ensure the btree roots which we increment in a
 	 * moment are up to date.
 	 */
-	__commit_transaction(pmd);
+	r = __commit_transaction(pmd);
+	if (r < 0) {
+		DMWARN("%s: __commit_transaction() failed, error = %d",
+		       __func__, r);
+		return r;
+	}
 
 	/*
 	 * Copy the superblock.
@@ -1283,10 +1324,10 @@
 {
 	int r = -EINVAL;
 
-	down_write(&pmd->root_lock);
+	pmd_write_lock(pmd);
 	if (!pmd->fail_io)
 		r = __reserve_metadata_snap(pmd);
-	up_write(&pmd->root_lock);
+	pmd_write_unlock(pmd);
 
 	return r;
 }
@@ -1331,10 +1372,10 @@
 {
 	int r = -EINVAL;
 
-	down_write(&pmd->root_lock);
+	pmd_write_lock(pmd);
 	if (!pmd->fail_io)
 		r = __release_metadata_snap(pmd);
-	up_write(&pmd->root_lock);
+	pmd_write_unlock(pmd);
 
 	return r;
 }
@@ -1377,19 +1418,19 @@
 {
 	int r = -EINVAL;
 
-	down_write(&pmd->root_lock);
+	pmd_write_lock_in_core(pmd);
 	if (!pmd->fail_io)
 		r = __open_device(pmd, dev, 0, td);
-	up_write(&pmd->root_lock);
+	pmd_write_unlock(pmd);
 
 	return r;
 }
 
 int dm_pool_close_thin_device(struct dm_thin_device *td)
 {
-	down_write(&td->pmd->root_lock);
+	pmd_write_lock_in_core(td->pmd);
 	__close_device(td);
-	up_write(&td->pmd->root_lock);
+	pmd_write_unlock(td->pmd);
 
 	return 0;
 }
@@ -1570,10 +1611,10 @@
 {
 	int r = -EINVAL;
 
-	down_write(&td->pmd->root_lock);
+	pmd_write_lock(td->pmd);
 	if (!td->pmd->fail_io)
 		r = __insert(td, block, data_block);
-	up_write(&td->pmd->root_lock);
+	pmd_write_unlock(td->pmd);
 
 	return r;
 }
@@ -1657,10 +1698,10 @@
 {
 	int r = -EINVAL;
 
-	down_write(&td->pmd->root_lock);
+	pmd_write_lock(td->pmd);
 	if (!td->pmd->fail_io)
 		r = __remove(td, block);
-	up_write(&td->pmd->root_lock);
+	pmd_write_unlock(td->pmd);
 
 	return r;
 }
@@ -1670,15 +1711,15 @@
 {
 	int r = -EINVAL;
 
-	down_write(&td->pmd->root_lock);
+	pmd_write_lock(td->pmd);
 	if (!td->pmd->fail_io)
 		r = __remove_range(td, begin, end);
-	up_write(&td->pmd->root_lock);
+	pmd_write_unlock(td->pmd);
 
 	return r;
 }
 
-int dm_pool_block_is_used(struct dm_pool_metadata *pmd, dm_block_t b, bool *result)
+int dm_pool_block_is_shared(struct dm_pool_metadata *pmd, dm_block_t b, bool *result)
 {
 	int r;
 	uint32_t ref_count;
@@ -1686,7 +1727,7 @@
 	down_read(&pmd->root_lock);
 	r = dm_sm_get_count(pmd->data_sm, b, &ref_count);
 	if (!r)
-		*result = (ref_count != 0);
+		*result = (ref_count > 1);
 	up_read(&pmd->root_lock);
 
 	return r;
@@ -1696,13 +1737,13 @@
 {
 	int r = 0;
 
-	down_write(&pmd->root_lock);
+	pmd_write_lock(pmd);
 	for (; b != e; b++) {
 		r = dm_sm_inc_block(pmd->data_sm, b);
 		if (r)
 			break;
 	}
-	up_write(&pmd->root_lock);
+	pmd_write_unlock(pmd);
 
 	return r;
 }
@@ -1711,13 +1752,13 @@
 {
 	int r = 0;
 
-	down_write(&pmd->root_lock);
+	pmd_write_lock(pmd);
 	for (; b != e; b++) {
 		r = dm_sm_dec_block(pmd->data_sm, b);
 		if (r)
 			break;
 	}
-	up_write(&pmd->root_lock);
+	pmd_write_unlock(pmd);
 
 	return r;
 }
@@ -1765,10 +1806,10 @@
 {
 	int r = -EINVAL;
 
-	down_write(&pmd->root_lock);
+	pmd_write_lock(pmd);
 	if (!pmd->fail_io)
 		r = dm_sm_new_block(pmd->data_sm, result);
-	up_write(&pmd->root_lock);
+	pmd_write_unlock(pmd);
 
 	return r;
 }
@@ -1777,12 +1818,16 @@
 {
 	int r = -EINVAL;
 
-	down_write(&pmd->root_lock);
+	/*
+	 * Care is taken to not have commit be what
+	 * triggers putting the thin-pool in-service.
+	 */
+	__pmd_write_lock(pmd);
 	if (pmd->fail_io)
 		goto out;
 
 	r = __commit_transaction(pmd);
-	if (r <= 0)
+	if (r < 0)
 		goto out;
 
 	/*
@@ -1790,7 +1835,7 @@
 	 */
 	r = __begin_transaction(pmd);
 out:
-	up_write(&pmd->root_lock);
+	pmd_write_unlock(pmd);
 	return r;
 }
 
@@ -1806,7 +1851,7 @@
 {
 	int r = -EINVAL;
 
-	down_write(&pmd->root_lock);
+	pmd_write_lock(pmd);
 	if (pmd->fail_io)
 		goto out;
 
@@ -1817,7 +1862,7 @@
 		pmd->fail_io = true;
 
 out:
-	up_write(&pmd->root_lock);
+	pmd_write_unlock(pmd);
 
 	return r;
 }
@@ -1948,10 +1993,10 @@
 {
 	int r = -EINVAL;
 
-	down_write(&pmd->root_lock);
+	pmd_write_lock(pmd);
 	if (!pmd->fail_io)
 		r = __resize_space_map(pmd->data_sm, new_count);
-	up_write(&pmd->root_lock);
+	pmd_write_unlock(pmd);
 
 	return r;
 }
@@ -1960,29 +2005,29 @@
 {
 	int r = -EINVAL;
 
-	down_write(&pmd->root_lock);
+	pmd_write_lock(pmd);
 	if (!pmd->fail_io) {
 		r = __resize_space_map(pmd->metadata_sm, new_count);
 		if (!r)
 			__set_metadata_reserve(pmd);
 	}
-	up_write(&pmd->root_lock);
+	pmd_write_unlock(pmd);
 
 	return r;
 }
 
 void dm_pool_metadata_read_only(struct dm_pool_metadata *pmd)
 {
-	down_write(&pmd->root_lock);
+	pmd_write_lock_in_core(pmd);
 	dm_bm_set_read_only(pmd->bm);
-	up_write(&pmd->root_lock);
+	pmd_write_unlock(pmd);
 }
 
 void dm_pool_metadata_read_write(struct dm_pool_metadata *pmd)
 {
-	down_write(&pmd->root_lock);
+	pmd_write_lock_in_core(pmd);
 	dm_bm_set_read_write(pmd->bm);
-	up_write(&pmd->root_lock);
+	pmd_write_unlock(pmd);
 }
 
 int dm_pool_register_metadata_threshold(struct dm_pool_metadata *pmd,
@@ -1992,25 +2037,28 @@
 {
 	int r;
 
-	down_write(&pmd->root_lock);
+	pmd_write_lock_in_core(pmd);
 	r = dm_sm_register_threshold_callback(pmd->metadata_sm, threshold, fn, context);
-	up_write(&pmd->root_lock);
+	pmd_write_unlock(pmd);
 
 	return r;
 }
 
 int dm_pool_metadata_set_needs_check(struct dm_pool_metadata *pmd)
 {
-	int r;
+	int r = -EINVAL;
 	struct dm_block *sblock;
 	struct thin_disk_superblock *disk_super;
 
-	down_write(&pmd->root_lock);
+	pmd_write_lock(pmd);
+	if (pmd->fail_io)
+		goto out;
+
 	pmd->flags |= THIN_METADATA_NEEDS_CHECK_FLAG;
 
 	r = superblock_lock(pmd, &sblock);
 	if (r) {
-		DMERR("couldn't read superblock");
+		DMERR("couldn't lock superblock");
 		goto out;
 	}
 
@@ -2019,7 +2067,7 @@
 
 	dm_bm_unlock(sblock);
 out:
-	up_write(&pmd->root_lock);
+	pmd_write_unlock(pmd);
 	return r;
 }