Hi Stephen: Thanks for the reply. Two questions: 1. Could you give me a pointer to the patch that flushes ext3 journal explicitly? I'd like an enhanced "sync" behavior that flushes everything to the disk. 2. Is there a way to sync metadata as well as data? Probably 1 and 2 are the same question.... Thanks a lot. If this problem cannot be solved, I may have to go back to ext2. Yes it takes more time to do fsck but or a 512M flash with 4 partitions it takes 11 seconds which is not that bad - and ext2 is in general more stable and faster.... I'm also wondering how many people are using ext3 on flash. Is there any better alternatives (like FAT maybe?) Hua > -----Original Message----- > From: Stephen C. Tweedie [mailto:sct@redhat.com] > Sent: Tuesday, September 17, 2002 12:58 AM > To: Hua Zhong > Cc: ext3-users@redhat.com > Subject: Re: ext3 sync problem > > > Hi, > > On Mon, Sep 16, 2002 at 10:07:30PM -0700, Hua Zhong wrote: > > > Here I have a problem with how sync works on ext3. Basically I > am using ext3 > > and GRUB on flash. What happens is: > > > > 1. ftp two big boot images into ext3 (on a flash) > > 2. do sync > > 3. reset immediately (without umounting) > > 4. GRUB cannot find the two images > > 5. boot with another image, and the two images are there (b/c > journal was > > replayed) > > Yep. sync() makes sure that the data is on the disk, but some of it > is still allowed to be in the journal at that point. That means that > it's in the filesystem, but not where grub expects to find it. > > I've already got a hack in ext3 to solve this for lilo --- whenever > ext3 gets a bmap() request (which asks us to return the absolute > location for the block on disk), if the file has been dirtied then it > flushes it out of the journal and onto permanent storage. > > > My first thinking was that ext3 sync doesn't sync all the data > but probably > > just the journal, but I asked ext3 maintainer and he said ext3 > sync all the > > data not just the journal, so I get confused. > > It _does_ sync the data. The problem is metadata. The data is in the > right place but the inodes, indirect blocks and directory entries > which refer to that data are still in the journal. > > Cheers, > Stephen _______________________________________________ Ext3-users@redhat.com https://listman.redhat.com/mailman/listinfo/ext3-users
