Re: umount and data is lost?
Hi Diego, On Sat, 05 Nov 2011 23:12:59 +0200 Diego wrote: > Hi list, > > I am trying to debug this problem in a system I am developing: > > at some point I need to write a number to a file, and then reboot via an > external device the machine. That device will cut of the power for a moment, > and the machine will power on again (this is to overcome a fault we could not > overcome otherwise). Before the reboot, I "umount" the proper partition and > then "sync". > > For some reason, on one machine we see that the data is not updated and the > original data is kept in the file. I konw empirically that if I add a > "sleep(5)" after the umount, and before the "reboot" the data is written to > the disk. > > Any tips how to debug this? > * the system is a TI 2.6.32 kernel (OMAP) > * the data is saved using fopen() Just to check - did you use fflush() or fclose() after you wrote it? Regards, Shlomi Fish -- - Shlomi Fish http://www.shlomifish.org/ "Humanity" - Parody of Modern Life - http://shlom.in/humanity 95% of Programmers consider 95% of the code they did not write, in the bottom 5%. Please reply to list if it's a mailing list post - http://shlom.in/reply . ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Scheduling a Meeting in a Cafe or Restaurant
2011/11/4 Amos Shapira > As I told wrote to you in private - use meetup.com, send a link to > linux-il and manage all of this off-list. > first, i think this thread is amusing, so i see no reason to let only ' meetup.com' subscribers enjoy it. if you think this is off topic, i suggest someone should explain how smoke signals are on topic (unless you are talking about open source implementation of smoke signals). ;-) > > > On 4 November 2011 03:16, Shlomi Fish wrote: > >> Hi Diego, >> >> On Wed, 2 Nov 2011 21:39:20 +0200 >> Diego Iastrubni wrote: >> >> > On יום רביעי 02 נובמבר 2011 16:33:22 Shlomi Fish wrote: >> > > On Wed, 2 Nov 2011 14:50:16 +0200 >> > > >> > > Stan Goodman wrote: >> > > > On Wednesday 02 November 2011 13:24:56 Shlomi Fish wrote: >> > > > > Hi all, >> > > > > >> > > > > I'd like to meet with a few people (whoever is interested) for >> chat >> > > > >> > > > Interested in what? >> > > >> > > interested in meeting. So to repharse: >> > > >> > > <<< >> > > I'd like with a few people (whoever is interested in such a meeting) >> for >> > > chat and food in a café or a restaurant >> > >> > You keep confusing between linux.org.il and jdate.co.il. >> >> Why do you think I confused between the Linux-IL mailing list and JDate? >> And >> why do you think I "keep" confusing between them? (I.e: it's a trend.) >> >> > >> > Shlomi - this is not a meetup ML at least not always, sometimes we >> do >> > import a movie and rent a cinema... >> >> I realise it's not an exclusively meetup meeting, but we have been >> announcing >> events on it for a long time, and I don't see why a real-life meeting of >> people >> who share similar interests should be disallowed. >> >> > Anyway, keep on topic, ok? You know, >> > techcnical shite related to linux and stuff, ya' know? ;-) >> >> I do keep on topic. >> >> Regards, >> >>Shlomi Fish >> >> -- >> - >> Shlomi Fish http://www.shlomifish.org/ >> List of Portability Libraries - http://shlom.in/port-libs >> >> Ran Eilam To Shlomi Fish: so what are you working on? Working on a new >> wiki >> about unit testing fortunes in freecell? >> >> Please reply to list if it's a mailing list post - http://shlom.in/reply. >> >> ___ >> Linux-il mailing list >> Linux-il@cs.huji.ac.il >> http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il >> > > > ___ > Linux-il mailing list > Linux-il@cs.huji.ac.il > http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il > > ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Scheduling a Meeting in a Cafe or Restaurant
On 6 November 2011 19:24, Erez D wrote: > > > 2011/11/4 Amos Shapira > >> As I told wrote to you in private - use meetup.com, send a link to >> linux-il and manage all of this off-list. >> > > first, i think this thread is amusing, so i see no reason to let only ' > meetup.com' subscribers enjoy it. > if you think this is off topic, i suggest someone should explain how smoke > signals are on topic (unless you are talking about open source > implementation of smoke signals). ;-) > I suggested meetup.com as soon as his first post went out. I don't mind the thread but think that meetup.com will help get it actually to happen instead of continuing this virtual haggling online. --Amos ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Scheduling a Meeting in a Cafe or Restaurant
Sorry, it doesn't work on my system: prompt> kill -SMOKE thread kill: unknown signal: SIGSMOKE So perhaps the smoke signals only work in the spring. Dov 2011/11/6 Amos Shapira > On 6 November 2011 19:24, Erez D wrote: > >> >> >> 2011/11/4 Amos Shapira >> >>> As I told wrote to you in private - use meetup.com, send a link to >>> linux-il and manage all of this off-list. >>> >> >> first, i think this thread is amusing, so i see no reason to let only ' >> meetup.com' subscribers enjoy it. >> if you think this is off topic, i suggest someone should explain how >> smoke signals are on topic (unless you are talking about open source >> implementation of smoke signals). ;-) >> > > I suggested meetup.com as soon as his first post went out. I don't mind > the thread but think that meetup.com will help get it actually to happen > instead of continuing this virtual haggling online. > > --Amos > > ___ > Linux-il mailing list > Linux-il@cs.huji.ac.il > http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il > > ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Scheduling a Meeting in a Cafe or Restaurant
On Nov 6, 2011, at 1:52 PM, Dov Grobgeld wrote: Sorry, it doesn't work on my system: prompt> kill -SMOKE thread kill: unknown signal: SIGSMOKE So perhaps the smoke signals only work in the spring. Smoking is bad for your health and has been thought so since the 1960's. Since UNIX is a product of the 1970's and Linux is based on UNIX, smoke signals were never implemented. Geof. -- Geoffrey S. Mendelson, N3OWJ/4X1GM My high blood pressure medicine reduces my midichlorian count. :-( ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
what happened to mplayerplug-in?
I want to see iba site. Once there was mplayer plugin. It doesn't appear anymore in the plugin list of firefox. I tried to download the source from http://mplayerplug-in.sourceforge.net/install.php#plugin but it fails to compile at make. is there other plugin that will allow viewing videos from iba web site? ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: what happened to mplayerplug-in?
Have you tried whatever Flash player is packaged for your distro? 2011/11/6 sara fink > I want to see iba site. Once there was mplayer plugin. It doesn't appear > anymore in the plugin list of firefox. I tried to download the source from > > http://mplayerplug-in.sourceforge.net/install.php#plugin > > but it fails to compile at make. > > is there other plugin that will allow viewing videos from iba web site? > > ___ > Linux-il mailing list > Linux-il@cs.huji.ac.il > http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il > > ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: what happened to mplayerplug-in?
Hi Sara, On Sun, 6 Nov 2011 14:39:51 +0200 sara fink wrote: > I want to see iba site. Once there was mplayer plugin. It doesn't appear > anymore in the plugin list of firefox. I tried to download the source from > > http://mplayerplug-in.sourceforge.net/install.php#plugin > > but it fails to compile at make. > > is there other plugin that will allow viewing videos from iba web site? There's the VLC Mozilla plugin: http://www.videolan.org/doc/vlc-user-guide/en/ch07.html I didn't have a lot of luck to get it running on Mageia Linux 2 (Cauldron), but maybe you'll fare better. Regards, Shlomi Fish -- - Shlomi Fish http://www.shlomifish.org/ Interview with Ben Collins-Sussman - http://shlom.in/sussman To have bugs is human; to fix them — divine. Please reply to list if it's a mailing list post - http://shlom.in/reply . ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Scheduling a Meeting in a Cafe or Restaurant
2011/11/6 Amos Shapira : > I suggested meetup.com as soon as his first post went out. I don't mind the > thread but think that meetup.com will help get it actually to happen instead > of continuing this virtual haggling online. > I wouldn't sign up to that service, or even click the link. If the meetup crowd decides on a time or a place, then let us know here. -- Dotan Cohen http://gibberish.co.il http://what-is-what.com ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Scheduling a Meeting in a Cafe or Restaurant
On Sun, Nov 6, 2011 at 13:56, geoffrey mendelson wrote: > Smoking is bad for your health and has been thought so since the 1960's. > Since UNIX is a product of the 1970's and Linux is based on UNIX, smoke > signals were never implemented. > Maybe there is no UI, but the device drivers are certainly there: http://en.wikipedia.org/wiki/Lp0_on_fire -- Dotan Cohen http://gibberish.co.il http://what-is-what.com ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: Scheduling a Meeting in a Cafe or Restaurant
If there's smoke, there's fire; if there's fire, there's rm -rf /* -Ari 2011/11/6 Erez D > > > 2011/11/4 Amos Shapira > >> As I told wrote to you in private - use meetup.com, send a link to >> linux-il and manage all of this off-list. >> > > first, i think this thread is amusing, so i see no reason to let only ' > meetup.com' subscribers enjoy it. > if you think this is off topic, i suggest someone should explain how smoke > signals are on topic (unless you are talking about open source > implementation of smoke signals). ;-) > >> >> >> On 4 November 2011 03:16, Shlomi Fish wrote: >> >>> Hi Diego, >>> >>> On Wed, 2 Nov 2011 21:39:20 +0200 >>> Diego Iastrubni wrote: >>> >>> > On יום רביעי 02 נובמבר 2011 16:33:22 Shlomi Fish wrote: >>> > > On Wed, 2 Nov 2011 14:50:16 +0200 >>> > > >>> > > Stan Goodman wrote: >>> > > > On Wednesday 02 November 2011 13:24:56 Shlomi Fish wrote: >>> > > > > Hi all, >>> > > > > >>> > > > > I'd like to meet with a few people (whoever is interested) for >>> chat >>> > > > >>> > > > Interested in what? >>> > > >>> > > interested in meeting. So to repharse: >>> > > >>> > > <<< >>> > > I'd like with a few people (whoever is interested in such a meeting) >>> for >>> > > chat and food in a café or a restaurant >>> > >>> > You keep confusing between linux.org.il and jdate.co.il. >>> >>> Why do you think I confused between the Linux-IL mailing list and JDate? >>> And >>> why do you think I "keep" confusing between them? (I.e: it's a trend.) >>> >>> > >>> > Shlomi - this is not a meetup ML at least not always, sometimes we >>> do >>> > import a movie and rent a cinema... >>> >>> I realise it's not an exclusively meetup meeting, but we have been >>> announcing >>> events on it for a long time, and I don't see why a real-life meeting of >>> people >>> who share similar interests should be disallowed. >>> >>> > Anyway, keep on topic, ok? You know, >>> > techcnical shite related to linux and stuff, ya' know? ;-) >>> >>> I do keep on topic. >>> >>> Regards, >>> >>>Shlomi Fish >>> >>> -- >>> - >>> Shlomi Fish http://www.shlomifish.org/ >>> List of Portability Libraries - http://shlom.in/port-libs >>> >>> Ran Eilam To Shlomi Fish: so what are you working on? Working on a new >>> wiki >>> about unit testing fortunes in freecell? >>> >>> Please reply to list if it's a mailing list post - http://shlom.in/reply. >>> >>> ___ >>> Linux-il mailing list >>> Linux-il@cs.huji.ac.il >>> http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il >>> >> >> >> ___ >> Linux-il mailing list >> Linux-il@cs.huji.ac.il >> http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il >> >> > > ___ > Linux-il mailing list > Linux-il@cs.huji.ac.il > http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il > > ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: umount and data is lost?
On Sat, Nov 05, 2011, Diego wrote about "umount and data is lost?": > overcome otherwise). Before the reboot, I "umount" the proper partition and > then "sync". I believe it is rather pointless to sync(1) after umount(1) as umount(1) already writes all the buffered data for that filesystem before it succeeds. You can see this behavior in action if you mount a slow USB flash drive, write a lot of data to it, and immediately umount - the umount often can take many seconds to finish, until all the data is actually written to the drive. > For some reason, on one machine we see that the data is not updated and the > original data is kept in the file. I konw empirically that if I add a > "sleep(5)" after the umount, and before the "reboot" the data is written to > the disk. The only thing I can think of is that the actual hard disk hardware has a write cache, and it is telling Linux it finished writing, while still having a few sectors cached - and the physical poweroff is causing it to loose its data. Does "hdparm -F" perhaps help? (after the umount, before the reboot) > * again the workaround is a "sleep(5)" Is sleep(5) the minimum that works? Nadav. -- Nadav Har'El| Sunday, Nov 6 2011, n...@math.technion.ac.il |- Phone +972-523-790466, ICQ 13349191 |If Barbie is so popular, why do you have http://nadav.harel.org.il |to buy her friends? ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: umount and data is lost?
> Does "hdparm -F" perhaps help? (after the umount, before the reboot) Eh, "hdparm -f" I guess? -- Oleg Goldshmidt | p...@goldshmidt.org ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: umount and data is lost?
On Sun, Nov 06, 2011, Oleg Goldshmidt wrote about "Re: umount and data is
lost?":
> > Does "hdparm -F" perhaps help? (after the umount, before the reboot)
>
> Eh, "hdparm -f" I guess?
I don't know, I didn't actually test what these do, but according to the
hdparm(8) manual page,
-f Sync and flush the buffer cache for the device on exit. This
operation is also performed internally as part of the -t and -T
timings and other options.
-F Flush the on-drive write cache buffer (older drives may not
implement this).
So -f sounds relevant, but I can't really say for sure what they mean
("on exit"? exit from what?). But "-F" sounds exactly what I wanted.
You can try both, and tell us if one of them helped.
--
Nadav Har'El| Sunday, Nov 6 2011,
n...@math.technion.ac.il |-
Phone +972-523-790466, ICQ 13349191 |"I don't use drugs, my dreams are
http://nadav.harel.org.il |frightening enough." -- M. C. Escher
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Re: what happened to mplayerplug-in?
Not yet, but I will give it a try On Sun, Nov 6, 2011 at 4:16 PM, Mordechai Behar < mordecha.be...@mail.huji.ac.il> wrote: > Have you tried whatever Flash player is packaged for your distro? > > 2011/11/6 sara fink > >> I want to see iba site. Once there was mplayer plugin. It doesn't appear >> anymore in the plugin list of firefox. I tried to download the source from >> >> http://mplayerplug-in.sourceforge.net/install.php#plugin >> >> but it fails to compile at make. >> >> is there other plugin that will allow viewing videos from iba web site? >> >> ___ >> Linux-il mailing list >> Linux-il@cs.huji.ac.il >> http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il >> >> > ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: what happened to mplayerplug-in?
thanks. will try this one too. On Sun, Nov 6, 2011 at 4:23 PM, Shlomi Fish wrote: > Hi Sara, > > On Sun, 6 Nov 2011 14:39:51 +0200 > sara fink wrote: > > > I want to see iba site. Once there was mplayer plugin. It doesn't appear > > anymore in the plugin list of firefox. I tried to download the source > from > > > > http://mplayerplug-in.sourceforge.net/install.php#plugin > > > > but it fails to compile at make. > > > > is there other plugin that will allow viewing videos from iba web site? > > There's the VLC Mozilla plugin: > > http://www.videolan.org/doc/vlc-user-guide/en/ch07.html > > I didn't have a lot of luck to get it running on Mageia Linux 2 > (Cauldron), but > maybe you'll fare better. > > Regards, > >Shlomi Fish > > -- > - > Shlomi Fish http://www.shlomifish.org/ > Interview with Ben Collins-Sussman - http://shlom.in/sussman > > To have bugs is human; to fix them — divine. > > Please reply to list if it's a mailing list post - http://shlom.in/reply . > ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
Re: umount and data is lost?
Hi all,
First of all, thanks for all the responces. I am here, instead of the
gazillion (usefull) answers just so I do not insult anyone... (or everyone?).
Some questions asked:
1) I did fclose() the file.
2) I tried sync() before the umount().
3) Instead of using system("umount...") I am using umount("...", MNT_FORCE).
Return value is OK=0.
4) I did not test which sleep() is the minimal.
5) Micha, HTML mail on this is is badbad. A kitten died because of you, thank
you (I am allergic to them)
6) hdparm... does it work on nand devices? I did mention this once or twise.
Just to make things clear: this is not a PC, it's an ARM based device.
On יום ראשון 06 נובמבר 2011 19:04:48 Nadav Har'El wrote:
> On Sat, Nov 05, 2011, Diego wrote about "umount and data is lost?":
> > overcome otherwise). Before the reboot, I "umount" the proper partition
> > and then "sync".
>
> I believe it is rather pointless to sync(1) after umount(1) as umount(1)
> already writes all the buffered data for that filesystem before it
> succeeds. You can see this behavior in action if you mount a slow USB
> flash drive, write a lot of data to it, and immediately umount - the
> umount often can take many seconds to finish, until all the data is
> actually written to the drive.
... and now the story gets even funnier:
I looked at the source again of my application, and it seems that the boot I
was doing is not the "external power off" reboot I was thinking of, but the
linux reboot(LINUX_REBOOT_CMD_RESTART) (man 2 reboot). This one was supposed
to umount() my partitions, and flush all data, correct? It does not in my case.
The problem on the system got fixed by calling the "external power off" reboot,
since I called sync() and umount() explicitly but how come
reboot(0x1234567) did not flush the buffers properly? I admit that the
partition
is not in /etc/fstab, but mounted "manually" by some stupid initscript, but...
I *am* confused.
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Re: umount and data is lost?
On Sun, Nov 06, 2011, Diego Iastrubni wrote about "Re: umount and data is
lost?":
> 6) hdparm... does it work on nand devices? I did mention this once or twise.
> Just to make things clear: this is not a PC, it's an ARM based device.
I don't know if there's anything special to say about "nand devices" or
"arm based devices". The only question is whether it is possible the
device in question has additional volatile RAM cache. I'd think an SSD
can be developed *without* write caches (e.g., if it pre-flashes unused
blocks), but I simply don't know. Reading what you wrote later, write
caches were probably not the problem anyway
> I looked at the source again of my application, and it seems that the boot I
> was doing is not the "external power off" reboot I was thinking of, but the
> linux reboot(LINUX_REBOOT_CMD_RESTART) (man 2 reboot). This one was supposed
> to umount() my partitions, and flush all data, correct? It does not in my
> case.
No, it doesn't. It just reboots immediately... Even the manual you
pointed us to says so ("If not preceded by a sync(2), data will be
lost.").
So if you called this reboot(), and did NOT umount or sync properly,
this explains everything!
Maybe you're confusing reboot(2) with reboot(8), the shell utility,
which does reboot the machine slowly, after stopping all applications,
flushing all filesystems, and so on?
--
Nadav Har'El| Sunday, Nov 6 2011,
n...@math.technion.ac.il |-
Phone +972-523-790466, ICQ 13349191 |I saw a book titled "Die Microsoft
http://nadav.harel.org.il |Windows". Turns out it was in German...
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Re: umount and data is lost?
"Nadav Har'El" writes: > On Sun, Nov 06, 2011, Oleg Goldshmidt wrote about "Re: umount and data is > lost?": >> > Does "hdparm -F" perhaps help? (after the umount, before the reboot) >> >> Eh, "hdparm -f" I guess? > > I don't know, I didn't actually test what these do, but according to the > hdparm(8) manual page, I plead temporary insanity. I didn't remember any of hdparm(8) options, so I fired the man page up, found -f (that looked relevant), and didn't find -F. I actually searched for it in vain... So I decided it was a typo. Now I am home on a different computer and it's there in the man page. I went back to the work laptop, and it magically appeared there as well. It is not clear which is more relevant, but probably -F. Re the question of relevance of hdparm(8) to NAND drives: as far as I understand hdparm(8) is shell interface to ATA or IDE ioctls, and "IDE NAND flash" seems a familiar combination... I am quite rusty, but you (Diego, not Nadav, sorry to mix subtopics) probably know if your NAND presents itself as an IDE or ATA device. So it well may be relevant and either hdparm or the appropriate ioctl (if in real code and not in script) may help, even as you already figured out the reboot procedure that saves the day. -- Oleg Goldshmidt | p...@goldshmidt.org ___ Linux-il mailing list Linux-il@cs.huji.ac.il http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il
