3.0-stable review patch. If anyone has any objections, please let us know.
------------------ From: Tao Ma <boyu...@taobao.com> commit 32c80b32c053dc52712dedac5e4d0aa7c93fc353 upstream. 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, but it doesn't fix the problem met by Michael actually. http://marc.info/?l=linux-ext4&m=131316851417460&w=2 Reported-and-Tested-by: Michael Tokarev<m...@tls.msk.ru> Signed-off-by: Eric Sandeen <sand...@redhat.com> Signed-off-by: Tao Ma <boyu...@taobao.com> Signed-off-by: "Theodore Ts'o" <ty...@mit.edu> Signed-off-by: Greg Kroah-Hartman <gre...@suse.de> --- fs/ext4/inode.c | 9 ++++++++- fs/ext4/page-io.c | 6 ++++-- 2 files changed, 12 insertions(+), 3 deletions(-) --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3645,8 +3645,15 @@ static void ext4_end_io_buffer_write(str 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); --- a/fs/ext4/page-io.c +++ b/fs/ext4/page-io.c @@ -338,8 +338,10 @@ 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)); _______________________________________________ stable mailing list stable@linux.kernel.org http://linux.kernel.org/mailman/listinfo/stable
