OSR's ntfsd List: STATUS_CANT_WAIT on sparse file write

Message 1 of 2

19 Jun 12 19:09

Russel McDonald

xxxxxx@swbell.net

Join Date: 30 Apr 2007

Posts To This List: 22

STATUS_CANT_WAIT on sparse file write

Hi, I have a mini filter driver filtering NTFS file IO, have filtered a create file of a file opened by SQL Server, and altered the attributes of that create file to make it sparse. It works except now on specific scenarios STATUS_CANT_WAIT is returned on the writes my driver passes through from sql server. I tried single threading all writes (block and wait on a kernel event and mutex lock a count of active writes, only allowing the count to get to 1). That did not help. Still get it on this one particular file, and at exactly the same write location as well (offset 2492538880) after quite a lot of previous activity. Simply changing the driver to not set the file to sparse makes the problem go away. Any inormmation on what may cause that STATUS_CANT_WAIT on sparse files and how to avoid it would be greatly appreciated. One theory I have is a certain area of the sparse file is being re-written with non-zero data (first write perhaps had a lot more zeroes) and now would have to rearrange the data and "now's not a good time". There is no disk space issue. Several hundred GB free remaining. Thanks in advance! Russel

Message 2 of 2

19 Jun 12 19:25

Tony Mason

xxxxxx@osr.com

Join Date:

Posts To This List: 2356

List Moderator

RE: STATUS_CANT_WAIT on sparse file write

Usually STATUS_CANT_WAIT is used to signal a locking problem of some sort. Given how reproducible this is, have you walked through the NTFS code path to see why it is returning this error value? Tony OSR

Posting Rules
You may not post new threads You may not post replies You may not post attachments	You must login to OSR Online AND be a member of the ntfsd list to be able to post.

All times are GMT -5. The time now is 08:19.