File system filters and transactions

Abstract

Aspects of the subject matter described herein relate to file system filters and transactions. In aspects, a filter may enlist to receive notification of events associated with a transaction. Afterwards, the filter may receive notification of a transaction event for which it has enlisted. In response to receiving notification of the transaction the filter may perform an action as appropriate. Aspects of the subject matter described herein may be applied to stacked and managed filters.

1 . A computer-readable medium having computer-executable instructions, comprising: 
 by a filter, enlisting to receive notification of events associated with a transaction;    at the filter, receiving notification of a transaction event; and    in response to receiving notification of a transaction event, performing an action.    
   
   
       2 . The computer-readable medium of  claim 1 , wherein enlisting to receive notification of events associated with a transaction comprises calling an interface of a filter manager that is associated with the filter and providing information that indicates events associated with the transaction in which the filter is interested.  
   
   
       3 . The computer-readable medium of  claim 1 , wherein the filter comprises a stacked filter that is given an opportunity to examine operations including operations related to transactions between an application and a file system.  
   
   
       4 . The computer-readable medium of  claim 1 , wherein the filter comprises a managed filter that is managed by a filter manager that is given an opportunity to examine operations including operations related to transactions between an application and a file system.  
   
   
       5 . The computer-readable medium of  claim 1 , wherein performing the action comprises sending notification that indicates that the filter has completed zero or more actions in response to receiving notification of a transaction event.  
   
   
       6 . The computer-readable medium of  claim 1 , further comprising registering with a filter manager associated with the filter and providing a transaction callback therewith.  
   
   
       7 . The computer-readable medium of  claim 6 , wherein receiving notification of a transaction event comprises receiving notification via the transaction callback.  
   
   
       8 . The computer-readable medium of  claim 1 , further comprising receiving a pointer to a related objects object that includes information that identifies a transaction ID and using the information to access a transaction context object associated with the transaction ID via an interface provided by a filter manager.  
   
   
       9 . The computer-readable medium of  claim 1 , wherein the transaction comprises a property of having every operation involved in the transaction succeed or having any tangible effects of any operation that did not succeed undone.  
   
   
       10 . A method implemented at least in part by a machine, comprising: 
 from a managed filter, receiving an enlistment request for notification of events associated with a transaction;    receiving information that indicates that a transaction event has occurred; and    sending a notification to the managed filter, wherein the notification is derived at least in part from the information.    
   
   
       11 . The method of  claim 10 , wherein the enlistment request indicates the transaction and specifies the events associated with the transaction for which notifications are to be sent to the managed filter.  
   
   
       12 . The method of  claim 11 , further comprising determining that the transaction event is one of the events associated with the transaction for which notification is to be sent to the managed filter.  
   
   
       13 . The method of  claim 10 , further comprising receiving a request to register for notification of events associated with transactions together with a callback to call to provide any notification of an event.  
   
   
       14 . The method of  claim 10 , further comprising receiving, from the managed filter, an indication of completion, and in response, sending a request to commit or rollback the transaction.  
   
   
       15 . The method of  claim 10 , wherein the notification comprises a pointer to an object that includes information via which context associated with the transaction is accessible.  
   
   
       16 . At least one computer-readable medium containing instructions which when executed by a computer, perform actions, comprising: 
 at an interface, receiving a message requesting notification of events associated with a transaction, wherein the transaction relates to files of a file system, wherein the interface is associated with a filter manager that manages one or more filters; and    in response, modifying a data structure to provide notification to the filter manager when events associated with the transaction occur.    
   
   
       17 . The at least one computer-readable medium of  claim 16 , wherein the message includes an indication of which events the filter manager is to be notified.  
   
   
       18 . The at least one computer-readable medium of  claim 16 , wherein the message includes a callback to call when events associated with the transaction occur.  
   
   
       19 . The at least one computer-readable medium of  claim 16 , further comprising creating, retrieving, or deleting a transaction context object via one or more interfaces associated with the filter manager.