Retrieving number of free unused eraseblocks in a UBI filesystem

[Martin Townsend]

On Wed, Dec 7, 2016 at 12:39 PM, Boris Brezillon
<boris.brezillon at free-electrons.com> wrote:
> On Wed, 7 Dec 2016 11:59:13 +0000
> Martin Townsend <mtownsend1973 at gmail.com> wrote:
>
>> Hi,
>>
>> I'm running a 4.1 Kernel and have a UBI Filesystem with 2 volumes
>> taking up all the NAND.
>> ubinfo -d 0
>> ubi0
>> Volumes count:                           2
>> Logical eraseblock size:                 126976 bytes, 124.0 KiB
>> Total amount of logical eraseblocks:     4016 (509935616 bytes, 486.3 MiB)
>> Amount of available logical eraseblocks: 0 (0 bytes)
>> Maximum count of volumes                 128
>> Count of bad physical eraseblocks:       56
>> Count of reserved physical eraseblocks:  24
>> Current maximum erase counter value:     15
>> Minimum input/output unit size:          2048 bytes
>> Character device major/minor:            249:0
>> Present volumes:                         0, 1
>>
>> So I'm guessing that the Total amount of logical erase blocks is 0 as
>> this is because I have 2 volumes of a fixed size that take up all the
>> available eraseblocks of the /dev/ubi0 device.
>>
>> Is there a way of getting, per volume preferably, the number of
>> eraseblocks that aren't being used? Or conversely get the number of
>> eraseblocks that are used as I can work it out from the total amount
>> of logical eraseblocks.
>
> cat /sys/class/ubi/ubiX_Y/reserved_ebs
>
> where X is the UBI device id and Y is the volume id.
>

Thanks for the swift reply, this seems to give me the total number of
eraseblocks:

# cat /sys/class/ubi/ubi0_1/reserved_ebs
3196

# ubinfo -d0 -n1
Volume ID:   1 (on ubi0)
Type:        dynamic
Alignment:   1
Size:        3196 LEBs (405815296 bytes, 387.0 MiB)
State:       OK
Name:        rootfs

# df -h .
Filesystem      Size  Used Avail Use% Mounted on
ubi0:rootfs     357M  135M  222M  38% /

What I would like to know is how many of them are being used and how
many are not.

>>
>> Many Thanks,
>> Martin.
>>
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>