Merge branch 'for-linus-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs

Pull btrfs cleanups and fixes from Chris Mason:
 "These are small cleanups, and also some fixes for our async worker
  thread initialization.

  I was having some trouble testing these, but it ended up being a
  combination of changing around my test servers and a shiny new
  schedule while atomic from the new start/finish_plug in
  writeback_sb_inodes().

  That one only hits on btrfs raid5/6 or MD raid10, and if I wasn't
  changing a bunch of things in my test setup at once it would have been
  really clear.  Fix for writeback_sb_inodes() on the way as well"

* 'for-linus-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  Btrfs: cleanup: remove unnecessary check before btrfs_free_path is called
  btrfs: async_thread: Fix workqueue 'max_active' value when initializing
  btrfs: Add raid56 support for updating  num_tolerated_disk_barrier_failures in btrfs_balance
  btrfs: Cleanup for btrfs_calc_num_tolerated_disk_barrier_failures
  btrfs: Remove noused chunk_tree and chunk_objectid from scrub_enumerate_chunks and scrub_chunk
  btrfs: Update out-of-date "skip parity stripe" comment

9 files changed, 82 insertions, 96 deletions

diff --git a/fs/btrfs/async-thread.c b/fs/btrfs/async-thread.c
index 1ce06c849a86..3e36e4adc4a3 100644
--- a/fs/btrfs/async-thread.c
+++ b/fs/btrfs/async-thread.c
@@ -42,8 +42,14 @@ struct __btrfs_workqueue {
 
 	/* Thresholding related variants */
 	atomic_t pending;
-	int max_active;
-	int current_max;
+
+	/* Up limit of concurrency workers */
+	int limit_active;
+
+	/* Current number of concurrency workers */
+	int current_active;
+
+	/* Threshold to change current_active */
 	int thresh;
 	unsigned int count;
 	spinlock_t thres_lock;
@@ -88,7 +94,7 @@ BTRFS_WORK_HELPER(scrubnc_helper);
 BTRFS_WORK_HELPER(scrubparity_helper);
 
 static struct __btrfs_workqueue *
-__btrfs_alloc_workqueue(const char *name, unsigned int flags, int max_active,
+__btrfs_alloc_workqueue(const char *name, unsigned int flags, int limit_active,
 			 int thresh)
 {
 	struct __btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_NOFS);
@@ -96,26 +102,31 @@ __btrfs_alloc_workqueue(const char *name, unsigned int flags, int max_active,
 	if (!ret)
 		return NULL;
 
-	ret->max_active = max_active;
+	ret->limit_active = limit_active;
 	atomic_set(&ret->pending, 0);
 	if (thresh == 0)
 		thresh = DFT_THRESHOLD;
 	/* For low threshold, disabling threshold is a better choice */
 	if (thresh < DFT_THRESHOLD) {
-		ret->current_max = max_active;
+		ret->current_active = limit_active;
 		ret->thresh = NO_THRESHOLD;
 	} else {
-		ret->current_max = 1;
+		/*
+		 * For threshold-able wq, let its concurrency grow on demand.
+		 * Use minimal max_active at alloc time to reduce resource
+		 * usage.
+		 */
+		ret->current_active = 1;
 		ret->thresh = thresh;
 	}
 
 	if (flags & WQ_HIGHPRI)
 		ret->normal_wq = alloc_workqueue("%s-%s-high", flags,
-						 ret->max_active,
-						 "btrfs", name);
+						 ret->current_active, "btrfs",
+						 name);
 	else
 		ret->normal_wq = alloc_workqueue("%s-%s", flags,
-						 ret->max_active, "btrfs",
+						 ret->current_active, "btrfs",
 						 name);
 	if (!ret->normal_wq) {
 		kfree(ret);
@@ -134,7 +145,7 @@ __btrfs_destroy_workqueue(struct __btrfs_workqueue *wq);
 
 struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name,
 					      unsigned int flags,
-					      int max_active,
+					      int limit_active,
 					      int thresh)
 {
 	struct btrfs_workqueue *ret = kzalloc(sizeof(*ret), GFP_NOFS);
@@ -143,14 +154,14 @@ struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name,
 		return NULL;
 
 	ret->normal = __btrfs_alloc_workqueue(name, flags & ~WQ_HIGHPRI,
-					      max_active, thresh);
+					      limit_active, thresh);
 	if (!ret->normal) {
 		kfree(ret);
 		return NULL;
 	}
 
 	if (flags & WQ_HIGHPRI) {
-		ret->high = __btrfs_alloc_workqueue(name, flags, max_active,
+		ret->high = __btrfs_alloc_workqueue(name, flags, limit_active,
 						    thresh);
 		if (!ret->high) {
 			__btrfs_destroy_workqueue(ret->normal);
@@ -180,7 +191,7 @@ static inline void thresh_queue_hook(struct __btrfs_workqueue *wq)
  */
 static inline void thresh_exec_hook(struct __btrfs_workqueue *wq)
 {
-	int new_max_active;
+	int new_current_active;
 	long pending;
 	int need_change = 0;
 
@@ -197,7 +208,7 @@ static inline void thresh_exec_hook(struct __btrfs_workqueue *wq)
 	wq->count %= (wq->thresh / 4);
 	if (!wq->count)
 		goto  out;
-	new_max_active = wq->current_max;
+	new_current_active = wq->current_active;
 
 	/*
 	 * pending may be changed later, but it's OK since we really
@@ -205,19 +216,19 @@ static inline void thresh_exec_hook(struct __btrfs_workqueue *wq)
 	 */
 	pending = atomic_read(&wq->pending);
 	if (pending > wq->thresh)
-		new_max_active++;
+		new_current_active++;
 	if (pending < wq->thresh / 2)
-		new_max_active--;
-	new_max_active = clamp_val(new_max_active, 1, wq->max_active);
-	if (new_max_active != wq->current_max)  {
+		new_current_active--;
+	new_current_active = clamp_val(new_current_active, 1, wq->limit_active);
+	if (new_current_active != wq->current_active)  {
 		need_change = 1;
-		wq->current_max = new_max_active;
+		wq->current_active = new_current_active;
 	}
 out:
 	spin_unlock(&wq->thres_lock);
 
 	if (need_change) {
-		workqueue_set_max_active(wq->normal_wq, wq->current_max);
+		workqueue_set_max_active(wq->normal_wq, wq->current_active);
 	}
 }
 
@@ -351,13 +362,13 @@ void btrfs_destroy_workqueue(struct btrfs_workqueue *wq)
 	kfree(wq);
 }
 
-void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int max)
+void btrfs_workqueue_set_max(struct btrfs_workqueue *wq, int limit_active)
 {
 	if (!wq)
 		return;
-	wq->normal->max_active = max;
+	wq->normal->limit_active = limit_active;
 	if (wq->high)
-		wq->high->max_active = max;
+		wq->high->limit_active = limit_active;
 }
 
 void btrfs_set_work_high_priority(struct btrfs_work *work)
diff --git a/fs/btrfs/async-thread.h b/fs/btrfs/async-thread.h
index b0b093b6afec..ad4d0647d1a6 100644
--- a/fs/btrfs/async-thread.h
+++ b/fs/btrfs/async-thread.h
@@ -69,7 +69,7 @@ BTRFS_WORK_HELPER_PROTO(scrubparity_helper);
 
 struct btrfs_workqueue *btrfs_alloc_workqueue(const char *name,
 					      unsigned int flags,
-					      int max_active,
+					      int limit_active,
 					      int thresh);
 void btrfs_init_work(struct btrfs_work *work, btrfs_work_func_t helper,
 		     btrfs_func_t func,
diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 564a7de17d99..e54dd5905cee 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -183,8 +183,7 @@ no_valid_dev_replace_entry_found:
 	}
 
 out:
-	if (path)
-		btrfs_free_path(path);
+	btrfs_free_path(path);
 	return ret;
 }
 
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 9ebd34f1c677..0d98aee34fee 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3443,6 +3443,26 @@ static int barrier_all_devices(struct btrfs_fs_info *info)
 	return 0;
 }
 
+int btrfs_get_num_tolerated_disk_barrier_failures(u64 flags)
+{
+	if ((flags & (BTRFS_BLOCK_GROUP_DUP |
+		      BTRFS_BLOCK_GROUP_RAID0 |
+		      BTRFS_AVAIL_ALLOC_BIT_SINGLE)) ||
+	    ((flags & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0))
+		return 0;
+
+	if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
+		     BTRFS_BLOCK_GROUP_RAID5 |
+		     BTRFS_BLOCK_GROUP_RAID10))
+		return 1;
+
+	if (flags & BTRFS_BLOCK_GROUP_RAID6)
+		return 2;
+
+	pr_warn("BTRFS: unknown raid type: %llu\n", flags);
+	return 0;
+}
+
 int btrfs_calc_num_tolerated_disk_barrier_failures(
 	struct btrfs_fs_info *fs_info)
 {
@@ -3452,13 +3472,12 @@ int btrfs_calc_num_tolerated_disk_barrier_failures(
 		       BTRFS_BLOCK_GROUP_SYSTEM,
 		       BTRFS_BLOCK_GROUP_METADATA,
 		       BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA};
-	int num_types = 4;
 	int i;
 	int c;
 	int num_tolerated_disk_barrier_failures =
 		(int)fs_info->fs_devices->num_devices;
 
-	for (i = 0; i < num_types; i++) {
+	for (i = 0; i < ARRAY_SIZE(types); i++) {
 		struct btrfs_space_info *tmp;
 
 		sinfo = NULL;
@@ -3476,44 +3495,21 @@ int btrfs_calc_num_tolerated_disk_barrier_failures(
 
 		down_read(&sinfo->groups_sem);
 		for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
-			if (!list_empty(&sinfo->block_groups[c])) {
-				u64 flags;
-
-				btrfs_get_block_group_info(
-					&sinfo->block_groups[c], &space);
-				if (space.total_bytes == 0 ||
-				    space.used_bytes == 0)
-					continue;
-				flags = space.flags;
-				/*
-				 * return
-				 * 0: if dup, single or RAID0 is configured for
-				 *    any of metadata, system or data, else
-				 * 1: if RAID5 is configured, or if RAID1 or
-				 *    RAID10 is configured and only two mirrors
-				 *    are used, else
-				 * 2: if RAID6 is configured, else
-				 * num_mirrors - 1: if RAID1 or RAID10 is
-				 *                  configured and more than
-				 *                  2 mirrors are used.
-				 */
-				if (num_tolerated_disk_barrier_failures > 0 &&
-				    ((flags & (BTRFS_BLOCK_GROUP_DUP |
-					       BTRFS_BLOCK_GROUP_RAID0)) ||
-				     ((flags & BTRFS_BLOCK_GROUP_PROFILE_MASK)
-				      == 0)))
-					num_tolerated_disk_barrier_failures = 0;
-				else if (num_tolerated_disk_barrier_failures > 1) {
-					if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
-					    BTRFS_BLOCK_GROUP_RAID5 |
-					    BTRFS_BLOCK_GROUP_RAID10)) {
-						num_tolerated_disk_barrier_failures = 1;
-					} else if (flags &
-						   BTRFS_BLOCK_GROUP_RAID6) {
-						num_tolerated_disk_barrier_failures = 2;
-					}
-				}
-			}
+			u64 flags;
+
+			if (list_empty(&sinfo->block_groups[c]))
+				continue;
+
+			btrfs_get_block_group_info(&sinfo->block_groups[c],
+						   &space);
+			if (space.total_bytes == 0 || space.used_bytes == 0)
+				continue;
+			flags = space.flags;
+
+			num_tolerated_disk_barrier_failures = min(
+				num_tolerated_disk_barrier_failures,
+				btrfs_get_num_tolerated_disk_barrier_failures(
+					flags));
 		}
 		up_read(&sinfo->groups_sem);
 	}
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index d4cbfeeeedd4..bdfb479ea859 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -139,6 +139,7 @@ struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
 				     u64 objectid);
 int btree_lock_page_hook(struct page *page, void *data,
 				void (*flush_fn)(void *));
+int btrfs_get_num_tolerated_disk_barrier_failures(u64 flags);
 int btrfs_calc_num_tolerated_disk_barrier_failures(
 	struct btrfs_fs_info *fs_info);
 int __init btrfs_end_io_wq_init(void);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 237da012f7d0..a0fa7253a2d7 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -6909,8 +6909,7 @@ out:
 
 	trace_btrfs_get_extent(root, em);
 
-	if (path)
-		btrfs_free_path(path);
+	btrfs_free_path(path);
 	if (trans) {
 		ret = btrfs_end_transaction(trans, root);
 		if (!err)
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index 9a11db0c47ee..a39f5d1144e8 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -3267,13 +3267,13 @@ static noinline_for_stack int scrub_stripe(struct scrub_ctx *sctx,
 			scrub_blocked_if_needed(fs_info);
 		}
 
-		/* for raid56, we skip parity stripe */
 		if (map->type & BTRFS_BLOCK_GROUP_RAID56_MASK) {
 			ret = get_raid56_logic_offset(physical, num, map,
 						      &logical,
 						      &stripe_logical);
 			logical += base;
 			if (ret) {
+				/* it is parity strip */
 				stripe_logical += base;
 				stripe_end = stripe_logical + increment;
 				ret = scrub_raid56_parity(sctx, map, scrub_dev,
@@ -3480,7 +3480,6 @@ out:
 
 static noinline_for_stack int scrub_chunk(struct scrub_ctx *sctx,
 					  struct btrfs_device *scrub_dev,
-					  u64 chunk_tree, u64 chunk_objectid,
 					  u64 chunk_offset, u64 length,
 					  u64 dev_offset, int is_dev_replace)
 {
@@ -3531,8 +3530,6 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
 	struct btrfs_root *root = sctx->dev_root;
 	struct btrfs_fs_info *fs_info = root->fs_info;
 	u64 length;
-	u64 chunk_tree;
-	u64 chunk_objectid;
 	u64 chunk_offset;
 	int ret = 0;
 	int slot;
@@ -3596,8 +3593,6 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
 		if (found_key.offset + length <= start)
 			goto skip;
 
-		chunk_tree = btrfs_dev_extent_chunk_tree(l, dev_extent);
-		chunk_objectid = btrfs_dev_extent_chunk_objectid(l, dev_extent);
 		chunk_offset = btrfs_dev_extent_chunk_offset(l, dev_extent);
 
 		/*
@@ -3630,9 +3625,8 @@ int scrub_enumerate_chunks(struct scrub_ctx *sctx,
 		dev_replace->cursor_right = found_key.offset + length;
 		dev_replace->cursor_left = found_key.offset;
 		dev_replace->item_needs_writeback = 1;
-		ret = scrub_chunk(sctx, scrub_dev, chunk_tree, chunk_objectid,
-				  chunk_offset, length, found_key.offset,
-				  is_dev_replace);
+		ret = scrub_chunk(sctx, scrub_dev, chunk_offset, length,
+				  found_key.offset, is_dev_replace);
 
 		/*
 		 * flush, submit all pending read and write bios, afterwards
diff --git a/fs/btrfs/tree-defrag.c b/fs/btrfs/tree-defrag.c
index a4b9c8b2d35a..f31db4325339 100644
--- a/fs/btrfs/tree-defrag.c
+++ b/fs/btrfs/tree-defrag.c
@@ -115,8 +115,7 @@ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
 		ret = -EAGAIN;
 	}
 out:
-	if (path)
-		btrfs_free_path(path);
+	btrfs_free_path(path);
 	if (ret == -EAGAIN) {
 		if (root->defrag_max.objectid > root->defrag_progress.objectid)
 			goto done;
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 76201d6f6ce4..6fc735869c18 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -3585,23 +3585,10 @@ int btrfs_balance(struct btrfs_balance_control *bctl,
 	} while (read_seqretry(&fs_info->profiles_lock, seq));
 
 	if (bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
-		int num_tolerated_disk_barrier_failures;
-		u64 target = bctl->sys.target;
-
-		num_tolerated_disk_barrier_failures =
-			btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
-		if (num_tolerated_disk_barrier_failures > 0 &&
-		    (target &
-		     (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID0 |
-		      BTRFS_AVAIL_ALLOC_BIT_SINGLE)))
-			num_tolerated_disk_barrier_failures = 0;
-		else if (num_tolerated_disk_barrier_failures > 1 &&
-			 (target &
-			  (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10)))
-			num_tolerated_disk_barrier_failures = 1;
-
-		fs_info->num_tolerated_disk_barrier_failures =
-			num_tolerated_disk_barrier_failures;
+		fs_info->num_tolerated_disk_barrier_failures = min(
+			btrfs_calc_num_tolerated_disk_barrier_failures(fs_info),
+			btrfs_get_num_tolerated_disk_barrier_failures(
+				bctl->sys.target));
 	}
 
 	ret = insert_balance_item(fs_info->tree_root, bctl);