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Message-ID: <49CCCB0A.6070701@nokia.com> Date: Fri, 27 Mar 2009 14:48:10 +0200 From: Artem Bityutskiy <Artem.Bityutskiy@...ia.com> To: Linux Kernel Mailing List <linux-kernel@...r.kernel.org> Subject: EXT4-ish "fixes" in UBIFS UBIFS has exactly the same properties like ext4 - in case of power cuts: 1. truncate/write/close leads to empty files 2. create/write/rename leads to empty files UBIFS is used in hand-held and and power-cuts are very often there, because users just remove battery often. I realize the "reality is different" argument, and already concluded that we need a similar changes as Theo has done for ext4: http://git.kernel.org/?p=linux/kernel/git/tytso/ext4.git;a=commitdiff;h=bf1b69c0db7f9b9d8f02e94d40b19fca8336b991 http://git.kernel.org/?p=linux/kernel/git/tytso/ext4.git;a=commitdiff;h=f32b730a69bd56c5c9d704d8b75f03e90e290971 http://git.kernel.org/?p=linux/kernel/git/tytso/ext4.git;a=commitdiff;h=8411e347c3306ed36b8ca88611bf5fbf4d27d705 We have a problem that user-space people do not want to use 'fsync()', even when they are pointed to their code which is doing create/write/rename/close without fsync(). They just say - this is file-system bug, it is fixed in ext4 now, just fix the bug in UBIFS. I tell them, that is not a fix, that is band-aid, because ext4 issues asynchronous write, and a power cut can lead to corruptions anyway. I tell them, we can make this in UBIFS, but please, anyway add fsync() to your application. They say - now, we will will not - you fix your UBIFS. And because there is so much flood and about this, it is so difficult to have reasonable arguments. I want to say people - please, still use fsync(), if this is about the performance/reliability trade-off - make it optional. But they instead say - respected people are on our side, go away. And point me this: http://www.advogato.org/person/mjg59/diary/195.html http://thread.gmane.org/gmane.linux.kernel/811167/focus=811700 http://article.gmane.org/gmane.comp.lang.perl.perl5.porters/67352 And they say that BTRFS and XFS are going to fix userspace as well, and point me at this: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/317781/comments/175 This all became so messy and controversial. What should I do to persuade userspace to use 'fsync()' even if we hack UBIFS similarly to ext4? Suggestions? -- Best Regards, Artem Bityutskiy (Артём Битюцкий) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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