3 files changed, 19 insertions, 21 deletions

diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index 43527fd78825..56b8522d5767 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -234,8 +234,17 @@ static inline int btrfs_inode_in_log(struct inode *inode, u64 generation)
 	    BTRFS_I(inode)->last_sub_trans <=
 	    BTRFS_I(inode)->last_log_commit &&
 	    BTRFS_I(inode)->last_sub_trans <=
-	    BTRFS_I(inode)->root->last_log_commit)
-		return 1;
+	    BTRFS_I(inode)->root->last_log_commit) {
+		/*
+		 * After a ranged fsync we might have left some extent maps
+		 * (that fall outside the fsync's range). So return false
+		 * here if the list isn't empty, to make sure btrfs_log_inode()
+		 * will be called and process those extent maps.
+		 */
+		smp_mb();
+		if (list_empty(&BTRFS_I(inode)->extent_tree.modified_extents))
+			return 1;
+	}
 	return 0;
 }
 
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index d296efe2d3e7..1d1ba083ca6e 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -4093,18 +4093,8 @@ log_extents:
 		}
 	}
 
-	write_lock(&em_tree->lock);
-	/*
-	 * If we're doing a ranged fsync and there are still modified extents
-	 * in the list, we must run on the next fsync call as it might cover
-	 * those extents (a full fsync or an fsync for other range).
-	 */
-	if (list_empty(&em_tree->modified_extents)) {
-		BTRFS_I(inode)->logged_trans = trans->transid;
-		BTRFS_I(inode)->last_log_commit =
-			BTRFS_I(inode)->last_sub_trans;
-	}
-	write_unlock(&em_tree->lock);
+	BTRFS_I(inode)->logged_trans = trans->transid;
+	BTRFS_I(inode)->last_log_commit = BTRFS_I(inode)->last_sub_trans;
 out_unlock:
 	if (unlikely(err))
 		btrfs_put_logged_extents(&logged_list);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 340a92d08e84..2c2d6d1d8eee 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -529,12 +529,12 @@ static noinline int device_list_add(const char *path,
 		 */
 
 		/*
-		 * As of now don't allow update to btrfs_fs_device through
-		 * the btrfs dev scan cli, after FS has been mounted.
+		 * For now, we do allow update to btrfs_fs_device through the
+		 * btrfs dev scan cli after FS has been mounted.  We're still
+		 * tracking a problem where systems fail mount by subvolume id
+		 * when we reject replacement on a mounted FS.
 		 */
-		if (fs_devices->opened) {
-			return -EBUSY;
-		} else {
+		if (!fs_devices->opened && found_transid < device->generation) {
 			/*
 			 * That is if the FS is _not_ mounted and if you
 			 * are here, that means there is more than one
@@ -542,8 +542,7 @@ static noinline int device_list_add(const char *path,
 			 * with larger generation number or the last-in if
 			 * generation are equal.
 			 */
-			if (found_transid < device->generation)
-				return -EEXIST;
+			return -EEXIST;
 		}
 
 		name = rcu_string_strdup(path, GFP_NOFS);