Hi, On Fri, 2004-02-13 at 21:47, Vijayan Prabhakaran wrote: > I have a question on fsync() and ext3's journaling modes. > > Assume that I call fsync(fd) on a file. > > If that file is in 'data=journal' mode, would the fsync() return once the > data gets safely into the journal ? Should do, yes. We don't record buffers as being on the inode dirty list after a write() in data=journal mode, so fsync's dirty-buffer-flush is a NOOP there. We _do_ record the buffers as being on the transaction list, so the transaction commit that fsync() does flushes to the journal but not to backing store. The eventual writeback still happens because of the normal journal checkpointing rules: we don't allow a journal wrap until the final writeback has happened. > On the other hand, if that file is in 'data=writeback' mode, would the > fsync() return only when the data gets safely into its actual location ? Yes. --Stephen _______________________________________________ Ext3-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/ext3-users
