MAX FileName allowed in Vista

NTFSD
1

Hi all , i need to query that what is the max limit for a file path in vista as i m perplexed seeing the variations in the filenaming scenarios.In XP i am aware of that the OS doesnt allows a file to be name more than 260 but i m not able to figure out what is the limit in Vista .please any one of you having any idea revert back to me ASAP i m blocked due to this issue.

thanks in advance
Sankalp

2

Look at the docs for the Win32 CreateFile API. Even in XP I believe it was
possible to have names up to 32K in length using the \?\ notation.

Doug

-----Original Message-----
From: xxxxx@lists.osr.com [mailto:bounce-378317-
xxxxx@lists.osr.com] On Behalf Of xxxxx@rsystems.com
Sent: Wednesday, August 26, 2009 7:39 AM
To: Windows File Systems Devs Interest List
Subject: [ntfsd] MAX FileName allowed in Vista

Hi all , i need to query that what is the max limit for a file path in
vista as i m perplexed seeing the variations in the filenaming
scenarios.In XP i am aware of that the OS doesnt allows a file to be
name more than 260 but i m not able to figure out what is the limit in
Vista .please any one of you having any idea revert back to me ASAP i m
blocked due to this issue.

thanks in advance
Sankalp

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3

The maximum full file path size on all NT versions is about 32K characters.
The 260 character limit is a WIN32 limit. I think that each part of the path
is limited to 255 characters.

Bill Wandel

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of
xxxxx@rsystems.com
Sent: Wednesday, August 26, 2009 8:39 AM
To: Windows File Systems Devs Interest List
Subject: [ntfsd] MAX FileName allowed in Vista

Hi all , i need to query that what is the max limit for a file path in vista
as i m perplexed seeing the variations in the filenaming scenarios.In XP i
am aware of that the OS doesnt allows a file to be name more than 260 but i
m not able to figure out what is the limit in Vista .please any one of you
having any idea revert back to me ASAP i m blocked due to this issue.

thanks in advance
Sankalp

NTFSD is sponsored by OSR

For our schedule of debugging and file system seminars (including our new fs
mini-filter seminar) visit:
http://www.osr.com/seminars

To unsubscribe, visit the List Server section of OSR Online at
http://www.osronline.com/page.cfm?name=ListServer

4

As usual, the answer depends on the context. Win32 limit is 260
characters, as you mention, and this frames a fairly practical limit
with regard to what most applications (explorer included) can be
reasonably expected to handle. But Win32 is only one component that
manages namespace. Ultimately, the path length limit is determined by
the underlying file system (or namespace manager). If you look in the
documentation for CreateFile you’ll see it provides a means to specify
paths of up to 32k characters. That limit is governed by the maximum
size of a Unicode string. In NTFS, however, it is possible to create
files with even longer paths (using relative opens for example).

cheers,
johnm
-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of
xxxxx@rsystems.com
Sent: Wednesday, August 26, 2009 6:39 AM
To: Windows File Systems Devs Interest List
Subject: [ntfsd] MAX FileName allowed in Vista

Hi all , i need to query that what is the max limit for a file path in
vista as i m perplexed seeing the variations in the filenaming
scenarios.In XP i am aware of that the OS doesnt allows a file to be
name more than 260 but i m not able to figure out what is the limit in
Vista .please any one of you having any idea revert back to me ASAP i m
blocked due to this issue.

thanks in advance
Sankalp

NTFSD is sponsored by OSR

For our schedule of debugging and file system seminars
(including our new fs mini-filter seminar) visit:
http://www.osr.com/seminars

To unsubscribe, visit the List Server section of OSR Online at
http://www.osronline.com/page.cfm?name=ListServer

5

>more than 260

This is only for Win32 names, the kernel names can be up to the limit of the UNICODE_STRING 16bit length, i.e. 32K characters.

–
Maxim S. Shatskih
Windows DDK MVP
xxxxx@storagecraft.com
http://www.storagecraft.com

6

Thanks a lot to u all

i would like to elaborate my problem to u all.actually i am working on a security software that uses minifilter architecture.i trap various IRPs and and change the behaviour for those calls according to my requirements.I found the behavior with long filenames justified in XP context but in Vista i am finding it a bit awkward.I have put a filename length check of MAX_PATH length at filter level which is working fine in XP as the behavior remains consistent as compared to windows explorer in XP , but when the same check is encountered in vista , the explorer view of my software stops displaying files which are deep under the tree view heirarchy with mammoth names. please help me out .

thanks again
Sankalp

7

>bit awkward.I have put a filename length check of MAX_PATH length

Remove this. The maximum filename length in the kernel is the maximum UNICODE_STRING length (32K chars).

–
Maxim S. Shatskih
Windows DDK MVP
xxxxx@storagecraft.com
http://www.storagecraft.com

8

thanks a lot Maxim for your valuable inputs and will make suitable changes in my code for various IRPs and will revert back to u in case i face any problem .

thanks again
Sankalp