No progress indicated for openstack image uploads

[cmouse]

Version 3e27660

When trying to monitor openstack image upload, only 0/s is shown.

progress -mp 3884149
[3884149] python3.8 /home/cmouse/Downloads/flatcar_production_openstack_image.raw
        0.0% (0 / 8.5 GiB) 0/s

strace -p 3884149
write(5, "\27\3\3 \30\230\200z\267\325h\v\206\333\223\207;\366\336\343p\222\333\352\270W\343f\322\3745\263"..., 8221) = 8221
read(4, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 8192) = 8192
write(5, "\27\3\3 \30\230\200z\267\325h\v\207\347\246\353\0\211\251\31\331\346\312\227\271*\273\303\351-\332\313"..., 8221) = 8221
read(4, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 8192) = 8192
write(5, "\27\3\3 \30\230\200z\267\325h\v\210\326~\226 \363s\246\30\376\31\235\366s\7\37>\343\326b"..., 8221) = 8221
read(4, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 8192) = 8192
write(5, "\27\3\3 \30\230\200z\267\325h\v\211\3405\312\272\250\367\373\307\5\26\214\355\272\352i\247\30\250\332"..., 8221) = 8221
read(4, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 8192) = 8192
write(5, "\27\3\3 \30\230\200z\267\325h\v\212}\261h\325\374o\324\335\367K\35\352_\360]\257\3537\f"..., 8221) = 8221
read(4, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 8192) = 8192
write(5, "\27\3\3 \30\230\200z\267\325h\v\213[\246\213V\217\341\211.\356q\370\356\343)6\373\352B\200"..., 8221) = 8221
read(4, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 8192) = 8192
write(5, "\27\3\3 \30\230\200z\267\325h\v\214\250DJ\355:\3634s1\342F<\207\3338\230\250\332\363"..., 8221) = 8221
read(4, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 8192) = 8192
write(5, "\27\3\3 \30\230\200z\267\325h\v\2156\1I\2320\232E5\313\217\303\t\226\260k\5\344\33'"..., 8221) = 8221
read(4, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 8192) = 8192
write(5, "\27\3\3 \30\230\200z\267\325h\v\216\340\342/c\300K\373eC\206\33\357\304\225\326\242I\347\325"..., 8221) = 8221
read(4, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 8192) = 8192

::::::::::::::
/proc/3884149/fdinfo/0
::::::::::::::
pos:	0
flags:	02002
mnt_id:	28
::::::::::::::
/proc/3884149/fdinfo/1
::::::::::::::
pos:	0
flags:	02002
mnt_id:	28
::::::::::::::
/proc/3884149/fdinfo/2
::::::::::::::
pos:	0
flags:	02002
mnt_id:	28
::::::::::::::
/proc/3884149/fdinfo/3
::::::::::::::
pos:	0
flags:	02100000
mnt_id:	30
::::::::::::::
/proc/3884149/fdinfo/4
::::::::::::::
pos:	3793813504
flags:	02100000
mnt_id:	30
::::::::::::::
/proc/3884149/fdinfo/5
::::::::::::::
pos:	0
flags:	02000002
mnt_id:	10
### after few seconds
::::::::::::::
/proc/3884149/fdinfo/0
::::::::::::::
pos:	0
flags:	02002
mnt_id:	28
::::::::::::::
/proc/3884149/fdinfo/1
::::::::::::::
pos:	0
flags:	02002
mnt_id:	28
::::::::::::::
/proc/3884149/fdinfo/2
::::::::::::::
pos:	0
flags:	02002
mnt_id:	28
::::::::::::::
/proc/3884149/fdinfo/3
::::::::::::::
pos:	0
flags:	02100000
mnt_id:	30
::::::::::::::
/proc/3884149/fdinfo/4
::::::::::::::
pos:	3860611072
flags:	02100000
mnt_id:	30
::::::::::::::
/proc/3884149/fdinfo/5
::::::::::::::
pos:	0
flags:	02000002
mnt_id:	10

[cmouse]

It would seem the problem is that the fd is seeked to 0, and then back constantly

fd->pos = 0
fd->pos = 4565688320
fd->pos = 0

[cmouse]

After some debugging it seems that the real problem is that the same file is opened twice:

$ ls -l /proc/3884149/fd/
total 0
lrwx------ 1 cmouse cmouse 64 maalis 18 12:21 0 -> /dev/pts/2
lrwx------ 1 cmouse cmouse 64 maalis 18 12:21 1 -> /dev/pts/2
lrwx------ 1 cmouse cmouse 64 maalis 18 12:21 2 -> /dev/pts/2
lr-x------ 1 cmouse cmouse 64 maalis 18 12:21 3 -> /home/cmouse/Downloads/flatcar_production_openstack_image.raw
lr-x------ 1 cmouse cmouse 64 maalis 18 12:21 4 -> /home/cmouse/Downloads/flatcar_production_openstack_image.raw
lrwx------ 1 cmouse cmouse 64 maalis 18 12:21 5 -> 'socket:[1314379516]'

And it's trying to measure progress from 3 and 4, and ends up looking only on 3, which isn't progressing. When I manually changed it to always look at 4, it shows progress.

[Xfennec]

This is a very specific situation, but we could imagine a very generic fix ("if the file is opened multiple times, look for the biggest seek").

[cmouse]

I think that fd 3 actually was always 0. So you could maybe just ignore it as it's not really progressing anywhere?