lkml.org 
[lkml]   [2002]   [Aug]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: Loop devices under NTFS
At 05:48 27/08/02, Andre Bonin wrote:
>"mount -o loop -r -t iso9660 /mnt/win_d/Source/Iso/Red\ Hat\
>7.3/valhalla-i386-disc1.iso /mnt/rh7.3/cd1"
>
>It gives me an error
>"ioctl: LOOP_SET_FD: Invalid argument"

I believe that NTFS does not provide
address_space_operations->{prepare,commit}_write for plain files, so
the version of loop.c in stock 2.5.31 will not work.

I posted an update for loop.c that I posted on August 15th:
( http://marc.theaimsgroup.com/?l=linux-kernel&m=102941520919910&w=2 ).
That update included a hack (originally conceived by Andrew Morton and
originally implemented Jari Ruusu) to use file_operations->{read,write}
for mounting files on file systems that do not provide
{prepare,commit}_write, although this involves an extra data copy if
a transformation (such as encryption) is selected.

I submitted the loop.c update to Linus at least a week ago, but
I have not seen it appear in
ftp://ftp.kernel.org/pub/linux/kernel/people/dwmw2/bk-2.5.

Side note:

There are only a few file systems that provide writable files
without aops->{prepare,commit}_write. I think they are just tmpfs,
ntfs and intermezzo. If all file systems that provided writable files
could be expected to provide {prepare,commit}_write, I could eliminate
the file_ops->{read,write} code from loop.c. I wish I understood if
there really is a need for a file system to be able to provide a
writable random access file (as opposed to /dev/tty) that does not
have aops->{prepare,commit}_write. I would be interesting in knowing
if there is anything preventing implementation of
{prepare,commit}_wriet in ntfs.

Adam J. Richter __ ______________ 575 Oroville Road
adam@yggdrasil.com \ / Milpitas, California 95035
+1 408 309-6081 | g g d r a s i l United States of America
"Free Software For The Rest Of Us."




-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:28    [W:0.070 / U:8.348 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site