ubiupdatevol
Jelle Martijn Kok
jmkok at youcom.nl
Wed Jul 15 07:21:20 EDT 2009
Why is it not possible to write directly to a static volume ?
eg. perform "wget http://server.com/kernel.bin -O /dev/ubi0_2"
ubiupdatevol first performs a ioctl + UBI_IOCVOLUP (with the size) and
then starts writing normally. Why not allow for open, write, close
without this ioctl ?
This gives 2 related issues:
1) ubi_start_update must be called - which is normally called by
ioctl(fd, UBI_IOCVOLUP, &bytes). I could imagine that "ubi_start_update"
(upd.c) is called at the time the (static) volume is opened for writing.
(inside the "vol_cdev_open" in cdev.c)
2) the amount of bytes is not available/known on front. The amount of
bytes is store "vol->upd_bytes" which is used to limit and to know when
the amount of data to be written to an ubi volume has been reached. At
that time, the LEB is written and the update marker is removed.
However why not write the final LEB and remove the update marker inside
"vol_cdev_release". As a "vol_cdev_release" is (and should) always
follow the last write.
If you think this would be a correct change to UBI and also viable (am I
overlooking something ?) I would be willing to make the changes and sent
them to you (for inspection).
Jelle Martijn Kok
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