From 46df06b85e28eaf430aa5c8f8aa26120fa746b72 Mon Sep 17 00:00:00 2001
From: David Sterba <dsterba@suse.com>
Date: Fri, 13 Jul 2018 20:46:30 +0200
Subject: [PATCH] btrfs: refactor block group replication factor calculation to
 a helper

There are many places that open code the duplicity factor of the block
group profiles, create a common helper. This can be easily extended for
more copies.

Signed-off-by: David Sterba <dsterba@suse.com>
---
 fs/btrfs/extent-tree.c | 36 ++++++++----------------------------
 fs/btrfs/super.c       | 11 +++--------
 fs/btrfs/volumes.c     | 11 +++++++++++
 fs/btrfs/volumes.h     |  2 ++
 4 files changed, 24 insertions(+), 36 deletions(-)

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 4f19bdca3214..fd109bfd528d 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3931,11 +3931,7 @@ static void update_space_info(struct btrfs_fs_info *info, u64 flags,
 	struct btrfs_space_info *found;
 	int factor;
 
-	if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
-		     BTRFS_BLOCK_GROUP_RAID10))
-		factor = 2;
-	else
-		factor = 1;
+	factor = btrfs_bg_type_to_factor(flags);
 
 	found = __find_space_info(info, flags);
 	ASSERT(found);
@@ -4576,6 +4572,7 @@ static int can_overcommit(struct btrfs_fs_info *fs_info,
 	u64 space_size;
 	u64 avail;
 	u64 used;
+	int factor;
 
 	/* Don't overcommit when in mixed mode. */
 	if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
@@ -4610,10 +4607,8 @@ static int can_overcommit(struct btrfs_fs_info *fs_info,
 	 * doesn't include the parity drive, so we don't have to
 	 * change the math
 	 */
-	if (profile & (BTRFS_BLOCK_GROUP_DUP |
-		       BTRFS_BLOCK_GROUP_RAID1 |
-		       BTRFS_BLOCK_GROUP_RAID10))
-		avail >>= 1;
+	factor = btrfs_bg_type_to_factor(profile);
+	avail = div_u64(avail, factor);
 
 	/*
 	 * If we aren't flushing all things, let us overcommit up to
@@ -6094,12 +6089,8 @@ static int update_block_group(struct btrfs_trans_handle *trans,
 		cache = btrfs_lookup_block_group(info, bytenr);
 		if (!cache)
 			return -ENOENT;
-		if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
-				    BTRFS_BLOCK_GROUP_RAID1 |
-				    BTRFS_BLOCK_GROUP_RAID10))
-			factor = 2;
-		else
-			factor = 1;
+		factor = btrfs_bg_type_to_factor(cache->flags);
+
 		/*
 		 * If this block group has free space cache written out, we
 		 * need to make sure to load it if we are removing space.  This
@@ -9359,13 +9350,7 @@ u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
 			continue;
 		}
 
-		if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
-					  BTRFS_BLOCK_GROUP_RAID10 |
-					  BTRFS_BLOCK_GROUP_DUP))
-			factor = 2;
-		else
-			factor = 1;
-
+		factor = btrfs_bg_type_to_factor(block_group->flags);
 		free_bytes += (block_group->key.offset -
 			       btrfs_block_group_used(&block_group->item)) *
 			       factor;
@@ -10175,12 +10160,7 @@ int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
 
 	memcpy(&key, &block_group->key, sizeof(key));
 	index = btrfs_bg_flags_to_raid_index(block_group->flags);
-	if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
-				  BTRFS_BLOCK_GROUP_RAID1 |
-				  BTRFS_BLOCK_GROUP_RAID10))
-		factor = 2;
-	else
-		factor = 1;
+	factor = btrfs_bg_type_to_factor(block_group->flags);
 
 	/* make sure this block group isn't part of an allocation cluster */
 	cluster = &fs_info->data_alloc_cluster;
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index d7a54c648c5f..efe8b03ce380 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -2107,14 +2107,9 @@ static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 				btrfs_account_ro_block_groups_free_space(found);
 
 			for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
-				if (!list_empty(&found->block_groups[i])) {
-					switch (i) {
-					case BTRFS_RAID_DUP:
-					case BTRFS_RAID_RAID1:
-					case BTRFS_RAID_RAID10:
-						factor = 2;
-					}
-				}
+				if (!list_empty(&found->block_groups[i]))
+					factor = btrfs_bg_type_to_factor(
+						btrfs_raid_array[i].bg_flag);
 			}
 		}
 
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 0b9023f52b2a..eca67529e536 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -7292,3 +7292,14 @@ void btrfs_reset_fs_info_ptr(struct btrfs_fs_info *fs_info)
 		fs_devices = fs_devices->seed;
 	}
 }
+
+/*
+ * Multiplicity factor for simple profiles: DUP, RAID1-like and RAID10.
+ */
+int btrfs_bg_type_to_factor(u64 flags)
+{
+	if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
+		     BTRFS_BLOCK_GROUP_RAID10))
+		return 2;
+	return 1;
+}
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 06d8bb7dd557..6943aab9bdd7 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -559,4 +559,6 @@ void btrfs_reset_fs_info_ptr(struct btrfs_fs_info *fs_info);
 bool btrfs_check_rw_degradable(struct btrfs_fs_info *fs_info,
 					struct btrfs_device *failing_dev);
 
+int btrfs_bg_type_to_factor(u64 flags);
+
 #endif
-- 
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