On Sun, 2007-04-29 at 17:26 -0700, Ethan Solomita wrote: > Trond Myklebust wrote: > > On Fri, 2007-04-27 at 18:21 -0700, Ethan Solomita wrote: > >> There are several places where we add together NR_UNSTABLE_FS and > >> NF_FILE_DIRTY: > >> > >> sync_inodes_sb() > >> balance_dirty_pages() > >> wakeup_pdflush() > >> wb_kupdate() > >> prefetch_suitable() > >> > >> I can trace a standard codepath where it seems both of these are set > >> on the same page: > >> > >> nfs_file_aops.commit_write -> > >> nfs_commit_write > >> nfs_updatepages > >> nfs_writepage_setup > >> nfs_wb_page > >> nfs_wb_page_priority > >> nfs_writepage_locked > >> nfs_flush_mapping > >> nfs_flush_list > >> nfs_flush_multi > >> nfs_write_partial_ops.rpc_call_done > >> nfs_writeback_done_partial > >> nfs_writepage_release > >> nfs_reschedule_unstable_write > >> nfs_mark_request_commit > >> incr NR_UNSTABLE_NFS > >> > >> nfs_file_aops.commit_write -> > >> nfs_commit_write > >> nfs_updatepage > >> __set_page_dirty_nobuffers > >> incr NF_FILE_DIRTY > >> > >> > >> This is the standard code path that derives from sys_write(). Can > >> someone either show how this code sequence can't happen, or confirm for > >> me that there's a bug? > >> -- Ethan > > > > It should not happen. If the page is on the unstable list, then it will > > be committed before nfs_updatepage is allowed to redirty it. See the > > recent fixes in 2.6.21-rc7. > > Above I present a codepath called straight from sys_write() which seems > to do what I say. I could be wrong, but can you address the code paths I > show above which seem to set both? > -- Ethan
Look carefully at nfs_update_request(): if !nfs_dirty_request(), then it returns -EBUSY, and so nfs_writepage_setup() will loop on nfs_wb_page(). IOW: if PG_NEED_COMMIT is set (which it should be if on the commit list) then nfs_writepage_setup() will loop... Trond - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
