Fengguang Wu <fengguang...@intel.com> writes: > On Wed, Sep 12, 2012 at 03:28:42AM +0900, OGAWA Hirofumi wrote: >> >> If bdi has BDI_CAP_NO_WRITEBACK, bdi_forker_thread() doesn't start >> writeback thread. This means there is no consumer of work item made >> by bdi_queue_work(). >> >> This adds to checking of !bdi_cap_writeback_dirty(sb->s_bdi) before >> calling bdi_queue_work(), otherwise queued work never be consumed. >> >> Signed-off-by: OGAWA Hirofumi <hirof...@mail.parknet.co.jp> >> --- >> >> fs/fs-writeback.c | 7 +++++-- >> 1 file changed, 5 insertions(+), 2 deletions(-) >> >> diff -puN fs/fs-writeback.c~noop_backing_dev_info-check-fix fs/fs-writeback.c >> --- linux/fs/fs-writeback.c~noop_backing_dev_info-check-fix 2012-09-11 >> 06:12:30.000000000 +0900 >> +++ linux-hirofumi/fs/fs-writeback.c 2012-09-11 06:12:30.000000000 +0900 >> @@ -120,6 +120,9 @@ __bdi_start_writeback(struct backing_dev >> { >> struct wb_writeback_work *work; >> >> + if (!bdi_cap_writeback_dirty(bdi)) >> + return; > > Will someone in the current kernel actually call > __bdi_start_writeback() on a BDI_CAP_NO_WRITEBACK bdi? > > If the answer is no, VM_BUG_ON(!bdi_cap_writeback_dirty(bdi)) looks better.
I guess nobody call it in current kernel though. Hmm.., but we also have check in __mark_inode_dirty(), nobody should be using it, right? If we defined it as the bug, I can't see what BDI_CAP_NO_WRITEBACK wants to do actually. We are not going to allow to disable the writeback task? I was going to use this to disable writeback task on my developing FS... Thanks. -- OGAWA Hirofumi <hirof...@mail.parknet.co.jp> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/