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19 Jun 12 19:09
Join Date: 30 Apr 2007
Posts To This List: 22
STATUS_CANT_WAIT on sparse file write
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
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!