On Fri, Aug 31, 2018 at 01:06:00AM +1200, Stuart Richards wrote:
>
> Attempting to defrag a file with e4defrag -v filetobedefragged on a Raspberry
> Pi gives the error "-v: No such file or directory while trying to open file
> system: /dev/root". The same command works as expected on an AMD64 system.
Thanks for reporting this bug!
When e4defrag is run as root, it tries to open the file system to get
some file system parameters; this isn't strictly needed; it uses the
information to improve the decision about whether or not the file is
already optimally defragged or not. The problem is that it does this
by trying to parse /etc/mtab (which is often a symlink to
/proc/self/mounts).
If on that particular system, the kernel reports the root file system
as "/dev/root", then e4defrag will try to use it. If /dev/root does
not exist (which ia likely) then e4defrag will print the above
mentioned error message and bail out.
There are a couple of bugs hiding here.
(a) The error message which is printed uses argv[1] instead of
argv[0], which is where "-v: No such file or directory...." is
coming from.
(b) E4defrag should not bail out; since it's not fatal if the file
system parameters can't be fetched (in fact e4defrag will never try if
not running as root).
(c) The way e4defrag is trying to find the file system is not really
the most intelligent; for one thing it will get misled with bind
mounts, and it can try to use the blkid library to find the device
name.
(d) If a large number of files are specified on the comamnd line,
e4defrag not cache the result of the file parameters, but instead
fetch them over and over again.
I'll fix (a) and (b) for now, but e4defrag really needs to be cleaned
up eventually.
Regards,
- Ted
