fstrim(8) discards unused blocks on a mounted filesystem. It is useful for
solid-state drives (SSDs) and thinly-provisioned storage.
Only trimming the full device (with no option) is supported.
Contributed by Richard W.M. Jones
Author: Anton Altaparmakov <anton@tuxera.com>
Date: Tue Feb 12 10:33:55 2013 +0000
Modify libntfs-3g to make use of hd library to get the legacy BIOS geometry
from EDD. We scan all whole disk devices on the system and check if they
match the open ntfs device and if not we scan all partition devices on the
system and check if they match the open ntfs device.
If we find a partition device to match then we find its parent device again
using the hd library.
Once we have the parent of the partition device or we matched a whole disk
device we get the legacy EDD sectors per track and heads again using the hd
library.
Use of the hd library is auto detected (based on finding <hd.h> header file,
being able to link against libhd and finding the hd_list symbol in libhd.
Use can also be disabled/enabled/libhd prefix specified at ./configure time.
See ./configure --help for details.
Note this obviously requires libhd to be installed. On Ubuntu 12/04 systems
the relevant packages needed are libhd-dev and libhd16 (on older Ubuntu
versions it will be libhdN where N is some number <= 16 but an easy way to
get the right package is to simply install libhd-dev which by dependency
pulls in the correct libhdN package) whilst on SLES systems the relevant
packages needed are hwinfo and hwinfo-devel.
For some reason, when the monted device is "/dev/mapper/*", a record
in the form "/dev/dm-*" ends up in /etc/mtab and the device cannot be
unmounted.
The reason is unclear, the /dev/mapper name is not a symlink, and the
function doing the name change is not known. No detailed feedback from
the users having met the issue.
The patch changes the name back to the /dev/mapper name after realpath()
is called, and, if there is an actual change, both the name passed to
ntfs-3g and the one passed to fuse and mount are logged in the hope
of getting a clue about what is happening.
But ntfs-3g is probably not the right place for a fix.
