Hi Andreas,
Andreas Dilger wrote:
On Oct 24, 2008 19:09 +0900, Akira Fujita wrote:
The EXT4_IOC_FIEMAP_INO is used to get extents information of
inode which set to ioctl.
The defragger uses this ioctl to check the fragment condition
and to get extents information in the specified block group.
Instead of having a separate IOC number for each such ioctl, instead
we implemented EXT4_IOC_WRAPPER, which is an root-specific ioctl that
passes in an inode number and a second IOC number so that arbitrary file
ioctls can be run on any inode by root.
The EXT4_IOC_WRAPPER ioctl seems to be usuful for many situations.
But the EXT4_IOC_FIEMAP_INO ioctl is used not only root user but also
non-root user to call fiemap,
so we cannot use the current EXT4_IOC_WRAPPER ioctl for defrag.
This was mentioned last time these patches were posted, but there was
no reply from you. Christoph suggested a more generic VFS open-by-inum,
which isn't impossible to do but would cause a lot of controversy I
think, while the EXT4_IOC_WRAPPER is at least contained within ext4,
but is more generically useful than EXT4_IOC_FIEMAP_INO.
Do you plan to add EXT4_IOC_WRAPPER into the ext4 patch queue?
Regards,
Akira Fujita
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