Hello Alexei,
Thanks for making me look in the correct direction. Indeed the
problem is in the paging io read. In one of the code path, the driver was
splitting the MDL into smaller chunks, and was allocating MDLs for these
smaller chunks using IoAllocateMdl instead of IoBuildPartialMdl. This caused
the pages to be marked as dirty and were eventually flushed by the
mod/mapped page writer.
I will change the logic to construct the smaller chunks using
IoBuildPartialMdl instead of IoAllocateMdl.
Thanks
-Kiran
-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Alexei Jelvis
Sent: Tuesday, June 07, 2005 12:07 AM
To: Windows File Systems Devs Interest List
Subject: RE: [ntfsd] Delayed write failed
You should provide more details on what your filter is doing, particularly
when processing Paging Read requests.
My guess is that there is something wrong in processing Paging read requests
that results in setting dirty bit for the page you just have read.
Alexei.
-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com]On Behalf Of Kiran Joshi
Sent: Monday, June 06, 2005 7:39 AM
To: Windows File Systems Devs Interest List
Subject: RE: [ntfsd] Delayed write failed
Some more updates on this :
The delayed write failed happens consistently on registry files, vmware redo
log files, and on outlook express inbox.dbx. It happens if I use notepad to
open these files, or copy these files using command line to some other
volume. I could not reproduce it by writing an application to mmap these
files. The views were mapped read/write but no view was modified. After
modifying the view explicitly I was able to reproduce the popup for all
files which I guess is expected.
Is there any way that the file’s data can get modified, or at least the
pages can get marked dirty, which I might have overlooked ? There are no
third party filters installed. It’s a plain xp pro sp2/2k3ee.
Any tips on how should I debug this problem ?
-Kiran
-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Kiran Joshi
Sent: Friday, June 03, 2005 11:36 PM
To: Windows File Systems Devs Interest List
Subject: [ntfsd] Delayed write failed
Hello,
I am developing a volume filter. I am facing a strange problem. I am
seeing a delayed write failed on a readonly NTFS volume. File system is
failing the write request with media_write_protect error(which I think is
correct). So far I am able to reproduce this behavior on XP SP2 and 2K3.
This happens if I open some registry related files
(windows\system32\config*) on the read only volume from notepad and close
notepad without modifying the file. This also happens if I just try to copy
these files to some other volume. I am not able to reproduce same behavior
with any other files on the same volume.
To make the volume readonly, the volume fails IOCTL_DISK_IS_WRITABLE
with STATUS_MEDIA_WRITE_PROTECTED error. Do I need to do something else to
make the volume readonly? If I try to create a file on that volume it indeed
fails with media write protect error and GetVolumeInformation also returns
VolumeIsReadonly.
I am not able to understand why is modified/mapped page writer trying to
write to a readonly volume?
thanks
-Kiran
Questions? First check the IFS FAQ at
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