This is to announce a candidate release of an extension to ntfs-3g for file
ownership and protections (ntfs-3g-1.1120SC.1, based on the standard version
ntfs-3g-1.1120).

Details and dowload are available on
http://pagesperso-orange.fr/b.andre/security.html

The only change since the latest beta-test version (ntfs-3g-1.1120SB.5, Dec
14th) is the use of an LRU cache to get the inode numbers and the
deactivation of cacheing of file attributes by FUSE. This decreases
significantly the CPU usage by ntfs-3g (the impact on CPU usage by fuse is
unknown) and fixes a hard link problem caused by the unawareness of hard
linked files by FUSE.

For instance the following sequence (wrong in standard ntfs-3g when run in a
shell script) now displays the correct result.

rm -f ntfs/link*
echo linked file > ntfs/link0
ln ntfs/link0 ntfs/link1
ln ntfs/link1 ntfs/link2
ls -l ntfs/link*
echo more >> ntfs/link1
# the sizes displayed are not the same
ls -l ntfs/link*

I have benchmarked this version on recompiling ntfs-3g from the tarball
(gzip, tar, configure, make), doing about 4000 file or directory openings
(among which 900 were file creations). The relative CPU usage by successive 
versions of ntfs-3g are as follows :

standard ntfs-3g no security           100% (reference)
ntfs-3g plus security no caching       130%
ntfs-3g plus security cached           108%
same plus inode number cacheing         45%
same without fuse attribute cacheing    47%

An equivalent ratio is met on the number of physical reads requested by
ntfs-3g (242661, instead of 534743 for the reference version), but the real
impact on data access times is probably much less because of the cacheing
done by the kernel. Moreover the cacheing has no effect on writings, so there
should be no impact on disk throughput when copying large files.

Regards

Jean-Pierre



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