On Sat, Dec 18, 2010 at 12:46:42PM +1100, Nick Piggin wrote: > --- linux-2.6.orig/Documentation/filesystems/porting 2010-12-18 00:32:44.000000000 +1100 > +++ linux-2.6/Documentation/filesystems/porting 2010-12-18 03:51:40.000000000 +1100 > +-- > +[mandatory] > + Inode writeback and syncing has undergone an overhaul. > +write_inode_now doesn't sync (unless ->write_inode *always* syncs) > + Could you perhaps give a bit more detail in the documentation about what sync_inode() is supposed to do? I gather that it is supposed to (based on the flags), do the specified combination of (a) do writeback for the pages corresponding to the specified range (if INODE_SYNC_DATA is given), (b) write out the inode if necessary depending on INODE_SYNC_DATA_METADATA (for fdatasync) and INODE_SYNC_DATA (for fsync). When sync_inode() returns, what is guaranteed is that the appropriate buffer_heads are dirtied (for both the metadata and the data if the file system is still using the buffer cache for data I/O) and/or the data has been pushed to the block I/O system, but the sync_inode() method does not wait force the dirtied buffers out to disk, and it does not wait for any initiated I/O to complete (either at the block I/O layer or guaranteeing that the data has hit the platters by issuing a barrier request). Do I have that right? If so, could we please add that to the documentation, just so it's clear? Thanks!! - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
