On 7/11/2013 3:40 PM, Markus Trippelsdorf wrote: > On 2013.07.11 at 15:24 -0500, Stan Hoeppner wrote: >> On 7/11/2013 6:28 AM, Markus Trippelsdorf wrote: >> ... >>>> Looking at the source: >>>> http://api.kde.org/4.10-api/kdelibs-apidocs/kdecore/html/ksavefile_8cpp_source.html#l00219 >>>> it appears that one can set an environment variable KDE_EXTRA_FSYNC to >>>> address this issue. >>>> >>>> However in my case it doesn't help. Even with KDE_EXTRA_FSYNC=1 I still >>>> loose my KDE settings in case of a crash. So the whole fsync thing might >>>> be a red herring. >>> >>> It turned out that the KDE_EXTRA_FSYNC variable doesn't affect KDE >>> config file handling at all. >>> So I've added an fsync in kconfigini.cpp (KConfigIniBackend::writeConfig) >>> and now I don't loose my settings anymore during kernel crash testing. >>> >>> That is until xfs eats my KDE config files (kwinrulesr in this case): >> >> Adding fsync in kconfigini.cpp apparently doesn't force fsync for all >> KDE file operations. You also have some Open Office files getting hosed >> due to lack of fsync. XFS is not the cause of these problems. >> >> The problem is that all of this desktop code was developed atop EXT3 >> which flushed to disk every 5 seconds. This made programmers sloppy as >> they didn't have to fsync to make sure data hit disk. This problem has >> been covered extensively by many, including Eric in other posts on his >> blog. There's a really simple way to test this: mount with sync. >> Report results after the next crash. If no files are corrupted then >> you've verified the problem lay squarely on the shoulders of these >> desktop developers who have abdicated their responsibility to make sure >> their file changes hit the disk, instead of relying on a broken >> filesystem do it for them. >> >> Worth noting, using EXT4 without the EXT3 flush emulation enabled will >> yield similar file corruption upon a crash. > > I'm not so sure. Of course a journaled filesystem is not a database > replacement, but wouldn't it be easier to address this issue in xfs > directly instead of hoping in vain that application developers will > fix their code someday? Apparently you missed the O_PONIES debate some 4 years ago. Take a guess as to what happens to XFS performance if it is modified to "fix" this app dev broken file on crash problem. Hint: a bunch of previously asynchronous operations must now to be forced to be synchronous. -- Stan _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
