Hi! On Sat 2009-01-03 21:32:11, Theodore Tso wrote: > On Sat, Jan 03, 2009 at 01:38:15PM +0100, Pavel Machek wrote: > > +Requirements > > +============ > > + > > +Ext3 expects disk/storage subsystem to behave sanely. On sanely > > +behaving disk subsystem, data that have been successfully synced will > > +stay on the disk. Sane means: > > + > > +* writes to media never fail. Even if disk returns error condition during > > + write, ext3 can't handle that correctly, because success on fsync was already > > + returned when data hit the journal. > > + > > + (Fortunately writes failing are very uncommon on disks, as they > > + have spare sectors they use when write fails.) > > This is not unique to ext3; per the discussion two weeks ago, this is > largely because of the fsync() interface not possibly being able to Ok, so I guess I should split the patch to truly ext3-specific part, and the part that is common for all the filesystems. I guess I'll need some help with everything but ext2 and ext3... > return errors caused by failures when creating or modifying parent > directories. Given this, it's a bit misleading to place this in the > Documentation/filesystems/ext3.txt. At the minimum it should include > a discussion about what the issues might be, and given that pretty > much any Unix/Linux filesystem doesn't have a way of reflecting these > errors to application programs, it probably should be in a > filesystem-independent documentation file. Ok. I'll have to think about good name of that file. > > +* either write caching is disabled, or hw can do barriers and they are enabled. > > + > > + (Note that barriers are disabled by default, use "barrier=1" > > + mount option after making sure hw can support them). > > We really should get akpm to agree to accept the patch to default > barriers by default instead. :-) :-). Yes, that would help a bit. (No, it is not complete solution. barrier=0/writeback on should be still documented as unsafe). Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html