Re: [RFC][PATCH] EXT3: problem with page fault inside a transaction
Andrew Morton <[email protected]> Wed, 11 Oct 2006 23:43:30 -0700
| Newsgroups | gmane.linux.kernel,gmane.linux.kernel.mm,gmane.comp.file-systems.ext2.devel |
|---|---|
| Message-ID | <[email protected]> |
On Thu, 12 Oct 2006 09:57:26 +0400 Dmitriy Monakhov <[email protected]> wrote: > While reading Andrew's generic_file_buffered_write patches i've remembered > one more EXT3 issue.journal_start() in prepare_write() causes different ranking > violations if copy_from_user() triggers a page fault. It could cause > GFP_FS allocation, re-entering into ext3 code possibly with a different > superblock and journal, ranking violation of journalling serialization > and mmap_sem and page lock and all other kinds of funny consequences. With the stuff Nick and I are looking at, we won't take pagefaults inside prepare_write()/commit_write() any more. > Our customers complain about this issue. Really? How often? What on earth are they doing to trigger this? writev() without the 2.6.18 writev() bugfix?