diff --git a/includes/filebackend/FSFileBackend.php b/includes/filebackend/FSFileBackend.php
index dd43f829212..97abc2720ce 100644
--- a/includes/filebackend/FSFileBackend.php
+++ b/includes/filebackend/FSFileBackend.php
@@ -191,14 +191,9 @@ class FSFileBackend extends FileBackendStore {
 		}
 
 		if ( file_exists( $dest ) ) {
-			if ( !empty( $params['overwrite'] ) ) {
-				$ok = unlink( $dest );
-				if ( !$ok ) {
-					$status->fatal( 'backend-fail-delete', $params['dst'] );
-					return $status;
-				}
-			} else {
-				$status->fatal( 'backend-fail-alreadyexists', $params['dst'] );
+			$ok = unlink( $dest );
+			if ( !$ok ) {
+				$status->fatal( 'backend-fail-delete', $params['dst'] );
 				return $status;
 			}
 		}
@@ -256,14 +251,9 @@ class FSFileBackend extends FileBackendStore {
 		}
 
 		if ( file_exists( $dest ) ) {
-			if ( !empty( $params['overwrite'] ) ) {
-				$ok = unlink( $dest );
-				if ( !$ok ) {
-					$status->fatal( 'backend-fail-delete', $params['dst'] );
-					return $status;
-				}
-			} else {
-				$status->fatal( 'backend-fail-alreadyexists', $params['dst'] );
+			$ok = unlink( $dest );
+			if ( !$ok ) {
+				$status->fatal( 'backend-fail-delete', $params['dst'] );
 				return $status;
 			}
 		}
@@ -321,18 +311,13 @@ class FSFileBackend extends FileBackendStore {
 		}
 
 		if ( file_exists( $dest ) ) {
-			if ( !empty( $params['overwrite'] ) ) {
-				// Windows does not support moving over existing files
-				if ( wfIsWindows() ) {
-					$ok = unlink( $dest );
-					if ( !$ok ) {
-						$status->fatal( 'backend-fail-delete', $params['dst'] );
-						return $status;
-					}
+			// Windows does not support moving over existing files
+			if ( wfIsWindows() ) {
+				$ok = unlink( $dest );
+				if ( !$ok ) {
+					$status->fatal( 'backend-fail-delete', $params['dst'] );
+					return $status;
 				}
-			} else {
-				$status->fatal( 'backend-fail-alreadyexists', $params['dst'] );
-				return $status;
 			}
 		}
 
@@ -424,14 +409,9 @@ class FSFileBackend extends FileBackendStore {
 		}
 
 		if ( file_exists( $dest ) ) {
-			if ( !empty( $params['overwrite'] ) ) {
-				$ok = unlink( $dest );
-				if ( !$ok ) {
-					$status->fatal( 'backend-fail-delete', $params['dst'] );
-					return $status;
-				}
-			} else {
-				$status->fatal( 'backend-fail-alreadyexists', $params['dst'] );
+			$ok = unlink( $dest );
+			if ( !$ok ) {
+				$status->fatal( 'backend-fail-delete', $params['dst'] );
 				return $status;
 			}
 		}
diff --git a/includes/filebackend/FileBackendStore.php b/includes/filebackend/FileBackendStore.php
index 5f562d2d8cb..dd0bec950b3 100644
--- a/includes/filebackend/FileBackendStore.php
+++ b/includes/filebackend/FileBackendStore.php
@@ -83,12 +83,12 @@ abstract class FileBackendStore extends FileBackend {
 
 	/**
 	 * Create a file in the backend with the given contents.
+	 * This will overwrite any file that exists at the destination.
 	 * Do not call this function from places outside FileBackend and FileOp.
 	 *
 	 * $params include:
 	 *   - content       : the raw file contents
 	 *   - dst           : destination storage path
-	 *   - overwrite     : overwrite any file that exists at the destination
 	 *   - disposition   : Content-Disposition header value for the destination
 	 *   - async         : Status will be returned immediately if supported.
 	 *                     If the status is OK, then its value field will be
@@ -106,9 +106,7 @@ abstract class FileBackendStore extends FileBackend {
 		} else {
 			$status = $this->doCreateInternal( $params );
 			$this->clearCache( array( $params['dst'] ) );
-			if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
-				$this->deleteFileCache( $params['dst'] ); // persistent cache
-			}
+			$this->deleteFileCache( $params['dst'] ); // persistent cache
 		}
 		wfProfileOut( __METHOD__ . '-' . $this->name );
 		wfProfileOut( __METHOD__ );
@@ -122,12 +120,12 @@ abstract class FileBackendStore extends FileBackend {
 
 	/**
 	 * Store a file into the backend from a file on disk.
+	 * This will overwrite any file that exists at the destination.
 	 * Do not call this function from places outside FileBackend and FileOp.
 	 *
 	 * $params include:
 	 *   - src           : source path on disk
 	 *   - dst           : destination storage path
-	 *   - overwrite     : overwrite any file that exists at the destination
 	 *   - disposition   : Content-Disposition header value for the destination
 	 *   - async         : Status will be returned immediately if supported.
 	 *                     If the status is OK, then its value field will be
@@ -145,9 +143,7 @@ abstract class FileBackendStore extends FileBackend {
 		} else {
 			$status = $this->doStoreInternal( $params );
 			$this->clearCache( array( $params['dst'] ) );
-			if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
-				$this->deleteFileCache( $params['dst'] ); // persistent cache
-			}
+			$this->deleteFileCache( $params['dst'] ); // persistent cache
 		}
 		wfProfileOut( __METHOD__ . '-' . $this->name );
 		wfProfileOut( __METHOD__ );
@@ -161,12 +157,12 @@ abstract class FileBackendStore extends FileBackend {
 
 	/**
 	 * Copy a file from one storage path to another in the backend.
+	 * This will overwrite any file that exists at the destination.
 	 * Do not call this function from places outside FileBackend and FileOp.
 	 *
 	 * $params include:
 	 *   - src           : source storage path
 	 *   - dst           : destination storage path
-	 *   - overwrite     : overwrite any file that exists at the destination
 	 *   - disposition   : Content-Disposition header value for the destination
 	 *   - async         : Status will be returned immediately if supported.
 	 *                     If the status is OK, then its value field will be
@@ -180,9 +176,7 @@ abstract class FileBackendStore extends FileBackend {
 		wfProfileIn( __METHOD__ . '-' . $this->name );
 		$status = $this->doCopyInternal( $params );
 		$this->clearCache( array( $params['dst'] ) );
-		if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
-			$this->deleteFileCache( $params['dst'] ); // persistent cache
-		}
+		$this->deleteFileCache( $params['dst'] ); // persistent cache
 		wfProfileOut( __METHOD__ . '-' . $this->name );
 		wfProfileOut( __METHOD__ );
 		return $status;
@@ -225,12 +219,12 @@ abstract class FileBackendStore extends FileBackend {
 
 	/**
 	 * Move a file from one storage path to another in the backend.
+	 * This will overwrite any file that exists at the destination.
 	 * Do not call this function from places outside FileBackend and FileOp.
 	 *
 	 * $params include:
 	 *   - src           : source storage path
 	 *   - dst           : destination storage path
-	 *   - overwrite     : overwrite any file that exists at the destination
 	 *   - disposition   : Content-Disposition header value for the destination
 	 *   - async         : Status will be returned immediately if supported.
 	 *                     If the status is OK, then its value field will be
@@ -245,9 +239,7 @@ abstract class FileBackendStore extends FileBackend {
 		$status = $this->doMoveInternal( $params );
 		$this->clearCache( array( $params['src'], $params['dst'] ) );
 		$this->deleteFileCache( $params['src'] ); // persistent cache
-		if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
-			$this->deleteFileCache( $params['dst'] ); // persistent cache
-		}
+		$this->deleteFileCache( $params['dst'] ); // persistent cache
 		wfProfileOut( __METHOD__ . '-' . $this->name );
 		wfProfileOut( __METHOD__ );
 		return $status;
diff --git a/includes/filebackend/SwiftFileBackend.php b/includes/filebackend/SwiftFileBackend.php
index fed496afcf5..f6d81bbd71c 100644
--- a/includes/filebackend/SwiftFileBackend.php
+++ b/includes/filebackend/SwiftFileBackend.php
@@ -201,12 +201,6 @@ class SwiftFileBackend extends FileBackendStore {
 		// (a) Check the destination container and object
 		try {
 			$dContObj = $this->getContainer( $dstCont );
-			if ( empty( $params['overwrite'] ) &&
-				$this->fileExists( array( 'src' => $params['dst'], 'latest' => 1 ) ) )
-			{
-				$status->fatal( 'backend-fail-alreadyexists', $params['dst'] );
-				return $status;
-			}
 		} catch ( NoSuchContainerException $e ) {
 			$status->fatal( 'backend-fail-create', $params['dst'] );
 			return $status;
@@ -240,14 +234,10 @@ class SwiftFileBackend extends FileBackendStore {
 			if ( !empty( $params['async'] ) ) { // deferred
 				$op = $obj->write_async( $params['content'] );
 				$status->value = new SwiftFileOpHandle( $this, $params, 'Create', $op );
-				if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
-					$status->value->affectedObjects[] = $obj;
-				}
+				$status->value->affectedObjects[] = $obj;
 			} else { // actually write the object in Swift
 				$obj->write( $params['content'] );
-				if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
-					$this->purgeCDNCache( array( $obj ) );
-				}
+				$this->purgeCDNCache( array( $obj ) );
 			}
 		} catch ( CDNNotEnabledException $e ) {
 			// CDN not enabled; nothing to see here
@@ -287,12 +277,6 @@ class SwiftFileBackend extends FileBackendStore {
 		// (a) Check the destination container and object
 		try {
 			$dContObj = $this->getContainer( $dstCont );
-			if ( empty( $params['overwrite'] ) &&
-				$this->fileExists( array( 'src' => $params['dst'], 'latest' => 1 ) ) )
-			{
-				$status->fatal( 'backend-fail-alreadyexists', $params['dst'] );
-				return $status;
-			}
 		} catch ( NoSuchContainerException $e ) {
 			$status->fatal( 'backend-fail-copy', $params['src'], $params['dst'] );
 			return $status;
@@ -337,15 +321,11 @@ class SwiftFileBackend extends FileBackendStore {
 					$op = $obj->write_async( $fp, filesize( $params['src'] ), true );
 					$status->value = new SwiftFileOpHandle( $this, $params, 'Store', $op );
 					$status->value->resourcesToClose[] = $fp;
-					if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
-						$status->value->affectedObjects[] = $obj;
-					}
+					$status->value->affectedObjects[] = $obj;
 				}
 			} else { // actually write the object in Swift
 				$obj->load_from_filename( $params['src'], true ); // calls $obj->write()
-				if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
-					$this->purgeCDNCache( array( $obj ) );
-				}
+				$this->purgeCDNCache( array( $obj ) );
 			}
 		} catch ( CDNNotEnabledException $e ) {
 			// CDN not enabled; nothing to see here
@@ -396,12 +376,6 @@ class SwiftFileBackend extends FileBackendStore {
 		try {
 			$sContObj = $this->getContainer( $srcCont );
 			$dContObj = $this->getContainer( $dstCont );
-			if ( empty( $params['overwrite'] ) &&
-				$this->fileExists( array( 'src' => $params['dst'], 'latest' => 1 ) ) )
-			{
-				$status->fatal( 'backend-fail-alreadyexists', $params['dst'] );
-				return $status;
-			}
 		} catch ( NoSuchContainerException $e ) {
 			$status->fatal( 'backend-fail-copy', $params['src'], $params['dst'] );
 			return $status;
@@ -420,14 +394,10 @@ class SwiftFileBackend extends FileBackendStore {
 			if ( !empty( $params['async'] ) ) { // deferred
 				$op = $sContObj->copy_object_to_async( $srcRel, $dContObj, $dstRel, null, $hdrs );
 				$status->value = new SwiftFileOpHandle( $this, $params, 'Copy', $op );
-				if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
-					$status->value->affectedObjects[] = $dstObj;
-				}
+				$status->value->affectedObjects[] = $dstObj;
 			} else { // actually write the object in Swift
 				$sContObj->copy_object_to( $srcRel, $dContObj, $dstRel, null, $hdrs );
-				if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
-					$this->purgeCDNCache( array( $dstObj ) );
-				}
+				$this->purgeCDNCache( array( $dstObj ) );
 			}
 		} catch ( CDNNotEnabledException $e ) {
 			// CDN not enabled; nothing to see here
@@ -474,12 +444,6 @@ class SwiftFileBackend extends FileBackendStore {
 		try {
 			$sContObj = $this->getContainer( $srcCont );
 			$dContObj = $this->getContainer( $dstCont );
-			if ( empty( $params['overwrite'] ) &&
-				$this->fileExists( array( 'src' => $params['dst'], 'latest' => 1 ) ) )
-			{
-				$status->fatal( 'backend-fail-alreadyexists', $params['dst'] );
-				return $status;
-			}
 		} catch ( NoSuchContainerException $e ) {
 			$status->fatal( 'backend-fail-move', $params['src'], $params['dst'] );
 			return $status;
@@ -500,15 +464,11 @@ class SwiftFileBackend extends FileBackendStore {
 				$op = $sContObj->move_object_to_async( $srcRel, $dContObj, $dstRel, null, $hdrs );
 				$status->value = new SwiftFileOpHandle( $this, $params, 'Move', $op );
 				$status->value->affectedObjects[] = $srcObj;
-				if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
-					$status->value->affectedObjects[] = $dstObj;
-				}
+				$status->value->affectedObjects[] = $dstObj;
 			} else { // actually write the object in Swift
 				$sContObj->move_object_to( $srcRel, $dContObj, $dstRel, null, $hdrs );
 				$this->purgeCDNCache( array( $srcObj ) );
-				if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
-					$this->purgeCDNCache( array( $dstObj ) );
-				}
+				$this->purgeCDNCache( array( $dstObj ) );
 			}
 		} catch ( CDNNotEnabledException $e ) {
 			// CDN not enabled; nothing to see here