[PATCH 7/9] btrfs: refactor with memcmp_fsid_changed helper

[Anand Jain <anand.jain@oracle.com>]

We often check if the metadata_uuid is not the same as fsid, and then we
check if the given fsid matches the metadata_uuid. This patch refactors
this logic into a function and utilize it.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
 fs/btrfs/volumes.c | 48 ++++++++++++++++++++++++++--------------------
 1 file changed, 27 insertions(+), 21 deletions(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 8738c8027421..730fc723524e 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -458,6 +458,20 @@ static noinline struct btrfs_fs_devices *find_fsid(
 	return NULL;
 }
 
+/*
+ * First, checks if the metadata_uuid is different from the fsid in the
+ * given fs_devices. Then, checks if the given fsid is the same as the
+ * metadata_uuid in the fs_devices. If it is, returns true; otherwise,
+ * returns false.
+ */
+static inline bool memcmp_fsid_changed(struct btrfs_fs_devices *fs_devices,
+				       u8 *fsid)
+{
+	return (memcmp(fs_devices->fsid, fs_devices->metadata_uuid,
+		       BTRFS_FSID_SIZE) != 0 &&
+		memcmp(fs_devices->metadata_uuid, fsid, BTRFS_FSID_SIZE) == 0);
+}
+
 static struct btrfs_fs_devices *find_fsid_with_metadata_uuid(
 				struct btrfs_super_block *disk_super)
 {
@@ -487,13 +501,11 @@ static struct btrfs_fs_devices *find_fsid_with_metadata_uuid(
 	 * CHANGING_FSID_V2 flag set.
 	 */
 	list_for_each_entry(fs_devices, &fs_uuids, fs_list) {
-		if (fs_devices->fsid_change &&
-		    memcmp(fs_devices->metadata_uuid,
-			   fs_devices->fsid, BTRFS_FSID_SIZE) != 0 &&
-		    memcmp(disk_super->metadata_uuid, fs_devices->metadata_uuid,
-			   BTRFS_FSID_SIZE) == 0) {
+		if (!fs_devices->fsid_change)
+			continue;
+
+		if (memcmp_fsid_changed(fs_devices, disk_super->metadata_uuid))
 			return fs_devices;
-		}
 	}
 
 	return find_fsid(disk_super->fsid, disk_super->metadata_uuid);
@@ -684,18 +696,16 @@ static struct btrfs_fs_devices *find_fsid_inprogress(
 	struct btrfs_fs_devices *fs_devices;
 
 	list_for_each_entry(fs_devices, &fs_uuids, fs_list) {
-		if (memcmp(fs_devices->metadata_uuid, fs_devices->fsid,
-			   BTRFS_FSID_SIZE) != 0 &&
-		    memcmp(fs_devices->metadata_uuid, disk_super->fsid,
-			   BTRFS_FSID_SIZE) == 0 && !fs_devices->fsid_change) {
+		if (fs_devices->fsid_change)
+			continue;
+
+		if (memcmp_fsid_changed(fs_devices,  disk_super->fsid))
 			return fs_devices;
-		}
 	}
 
 	return find_fsid(disk_super->fsid, NULL);
 }
 
-
 static struct btrfs_fs_devices *find_fsid_changed(
 					struct btrfs_super_block *disk_super)
 {
@@ -712,10 +722,7 @@ static struct btrfs_fs_devices *find_fsid_changed(
 	 */
 	list_for_each_entry(fs_devices, &fs_uuids, fs_list) {
 		/* Changed UUIDs */
-		if (memcmp(fs_devices->metadata_uuid, fs_devices->fsid,
-			   BTRFS_FSID_SIZE) != 0 &&
-		    memcmp(fs_devices->metadata_uuid, disk_super->metadata_uuid,
-			   BTRFS_FSID_SIZE) == 0 &&
+		if (memcmp_fsid_changed(fs_devices, disk_super->metadata_uuid) &&
 		    memcmp(fs_devices->fsid, disk_super->fsid,
 			   BTRFS_FSID_SIZE) != 0)
 			return fs_devices;
@@ -746,11 +753,10 @@ static struct btrfs_fs_devices *find_fsid_reverted_metadata(
 	 * fs_devices equal to the FSID of the disk.
 	 */
 	list_for_each_entry(fs_devices, &fs_uuids, fs_list) {
-		if (memcmp(fs_devices->fsid, fs_devices->metadata_uuid,
-			   BTRFS_FSID_SIZE) != 0 &&
-		    memcmp(fs_devices->metadata_uuid, disk_super->fsid,
-			   BTRFS_FSID_SIZE) == 0 &&
-		    fs_devices->fsid_change)
+		if (!fs_devices->fsid_change)
+			continue;
+
+		if (memcmp_fsid_changed(fs_devices, disk_super->fsid))
 			return fs_devices;
 	}
 
-- 
2.38.1