On 8/13/11 11:02 AM, Tao Ma wrote: > From: Tao Ma <boyu.mt@xxxxxxxxxx> > > Hi Michael, > could you please check whether this patch work for you? Thanks, this is the patch I meant to send, I guess ;) I think I missed the "|=" case before :( given that every place we set it requires a test and an increment if not set, maybe a helper to do all that is in order? -Eric > > Subject: [PATCH] ext4: Set unwritten flag and increase i_aiodio_unwritten simultaneously. > From 4f1d797973da8b5cf79f58cc1e4d22efb9d46d19 Mon Sep 17 00:00:00 2001 > From: Tao Ma <boyu.mt@xxxxxxxxxx> > Date: Sat, 13 Aug 2011 23:50:28 +0800 > Subject: [PATCH] ext4: Set unwritten flag and increase i_aiodio_unwritten simultaneously. > > EXT4_IO_END_UNWRITTEN flag set and the increase of i_aiodio_unwritten should > be done simultaneously since ext4_end_io_nolock always clear the flag and > decrease the counter in the same time. > > We don't increase i_aiodio_unwritten when setting EXT4_IO_END_UNWRITTEN so > it will go nagative and causes some process to wait forever. > > Part of the patch came from Eric in his e-mail. > http://marc.info/?l=linux-ext4&m=131316851417460&w=2 > > Reported-by: Michael Tokarev<mjt@xxxxxxxxxx> > Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx> > Signed-off-by: Tao Ma <boyu.mt@xxxxxxxxxx> > --- > fs/ext4/inode.c | 9 ++++++++- > fs/ext4/page-io.c | 6 ++++-- > 2 files changed, 12 insertions(+), 3 deletions(-) > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index d47264c..40c0b10 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -2668,8 +2668,15 @@ static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate) > goto out; > } > > - io_end->flag = EXT4_IO_END_UNWRITTEN; > + /* > + * It may be over-defensive here to check EXT4_IO_END_UNWRITTEN now, > + * but being more careful is always safe for the future change. > + */ > inode = io_end->inode; > + if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) { > + io_end->flag |= EXT4_IO_END_UNWRITTEN; > + atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); > + } > > /* Add the io_end to per-inode completed io list*/ > spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags); > diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c > index 430c401..78839af 100644 > --- a/fs/ext4/page-io.c > +++ b/fs/ext4/page-io.c > @@ -334,8 +334,10 @@ submit_and_retry: > if ((io_end->num_io_pages >= MAX_IO_PAGES) && > (io_end->pages[io_end->num_io_pages-1] != io_page)) > goto submit_and_retry; > - if (buffer_uninit(bh)) > - io->io_end->flag |= EXT4_IO_END_UNWRITTEN; > + if (buffer_uninit(bh) && !(io_end->flag & EXT4_IO_END_UNWRITTEN)) { > + io_end->flag |= EXT4_IO_END_UNWRITTEN; > + atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten); > + } > io->io_end->size += bh->b_size; > io->io_next_block++; > ret = bio_add_page(io->io_bio, bh->b_page, bh->b_size, bh_offset(bh)); -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
