Oplock break in file

Sometimes the client will receive the break notification, process it, and respond by releasing its oplock. When that happens, my server will respond to the break acknowledgement, and grant the new create.

Everyone in happy. Other times, however, the client will receive the break and seemingly just ignore it. What is more, the same types of tasks being done on the client consistently fail or succeed. After the oplock timer expires, I have the server return an error to the second create request since the oplock couldn't be broken. The client will then close the original file, and repeat the second open, and is able to complete the task it was attempting.

I am sure that all the SMB2 packets are being received because I ran a wireshark trace directly from the client. I have been testing with Windows Vista, 7, and 8 clients, and have observed the same behavior in all three places. I tried looking for evidence of others running into this problem but did not find anything that helped me to figure out what is going on with this.

Is there a known issue where Windows SMB2 clients do not always respond to break notifications? Since NT 3. What will we do? Cache data on local machine. Because under this scenario performing cache will cause the file content inconsistent.

Cache your changes locally. Oplock break, return your changes on data. If both client 1 and 2 just want to read file A, can they share an oplock? Which means they can read-ahead and cache the result at local. Cache read-ahead at local.

Writing from client3 will break all Lv1 oplock. If client 1 has a Lv1 oplock on file A, and client 2 just want to read file A. After acknowledge the break, client 2 will be granted a Lv2. If file is oplocked, any action that will result in oplock break will be blocked until acknowledge from the owner. If oplocked will be broke, the thread will not be blocked.

Lv 2 : Shared. Batch : Exclusive. Applications and drivers can also use oplocks to transparently access files without affecting other applications that might need to use those files. File systems like NTFS support multiple data streams per file. Oplocks are granted on stream handles, meaning that the operations apply to the given open stream of a file and, in general, operations on one stream do not affect oplocks on a different stream.

There are exceptions to this, which are explicitly listed below. For file systems that do not support alternate data streams, such as FAT, think of "file" when this document refers to "stream". A Level 2 or shared oplock indicates that there are multiple readers of a stream and no writers. This supports client read caching. A Level 1 or exclusive oplock allows a client to open a stream for exclusive access and allows the client to perform arbitrary buffering.

This supports client read caching and write caching. A Batch oplock also exclusive allows a client to keep a stream open on the server even though the local accessor on the client machine has closed the stream.

This supports scenarios where the client needs to repeatedly open and close the same file, such as during batch script execution. This supports client read caching, write caching, and handle caching. A Filter oplock also exclusive allows applications and file system filters including minifilters , which open and read stream data, a way to "back out" when other applications, clients, or both try to access the same stream. When Level 2, Read, and, under certain circumstances see note , Read-Handle oplocks break, the system does not wait for an acknowledgment.

This is because there should be no cached state on the stream that needs to be restored to the file before allowing other clients access to it.

There are certain file system operations which check the current oplock state to determine if the oplock needs to be broken. The following sections list each operation and describe what triggers an oplock break, what determines the level to which the oplock breaks, and whether an acknowledgment of the break is required:.

Note The above listed per-operation topics describe the details of when a break of a Read-Handle oplock results in the pending of the operation that broke the oplock. Skip to main content. This browser is no longer supported. Download Microsoft Edge More info.