Messages in this thread | | | From | Nikanth Karthikesan <> | Subject | Re: [PATCH] Block - Honour barrier requests in loop driver | Date | Tue, 24 Mar 2009 11:24:35 +0530 |
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On Wednesday 18 March 2009 10:28:20 Nikanth Karthikesan wrote: > On Wednesday 18 March 2009 00:39:05 Christoph Hellwig wrote: > > On Tue, Mar 17, 2009 at 05:39:49PM +0530, Nikanth Karthikesan wrote: > > > + if (!file->f_op || !file->f_op->fsync) { > > > + ret = -EOPNOTSUPP; > > > + goto out; > > > + } > > > > file->f_op is never zero, so you can remove the checks for that. > > Otherwise looks good. > > Thanks for reviewing. I've removed that check. > > Jens, Can you merge this? > Hi Jens
Did you get to look at this? Can you merge this?
Thanks Nikanth
> > Honour barrier requests in the loop back block device driver. > In case of barrier bios, flush the backing file once before processing the > barrier and once after to guarantee ordering. In case of filesystems that > does not support fsync, barrier bios would be failed with -EOPNOTSUPP. > > Signed-off-by: Nikanth Karthikesan <knikanth@suse.de> > > --- > > diff --git a/drivers/block/loop.c b/drivers/block/loop.c > index bf03455..cac7894 100644 > --- a/drivers/block/loop.c > +++ b/drivers/block/loop.c > @@ -474,10 +474,35 @@ static int do_bio_filebacked(struct loop_device *lo, > struct bio *bio) int ret; > > pos = ((loff_t) bio->bi_sector << 9) + lo->lo_offset; > - if (bio_rw(bio) == WRITE) > + > + if (bio_rw(bio) == WRITE) { > + int barrier = bio_barrier(bio); > + struct file *file = lo->lo_backing_file; > + > + if (barrier) { > + if (unlikely(!file->f_op->fsync)) { > + ret = -EOPNOTSUPP; > + goto out; > + } > + > + ret = vfs_fsync(file, file->f_path.dentry, 0); > + if (unlikely(ret)) { > + ret = -EIO; > + goto out; > + } > + } > + > ret = lo_send(lo, bio, pos); > - else > + > + if (barrier && !ret) { > + ret = vfs_fsync(file, file->f_path.dentry, 0); > + if (unlikely(ret)) > + ret = -EIO; > + } > + } else > ret = lo_receive(lo, bio, lo->lo_blocksize, pos); > + > +out: > return ret; > } > > @@ -825,6 +850,10 @@ static int loop_set_fd(struct loop_device *lo, fmode_t > mode, blk_queue_make_request(lo->lo_queue, loop_make_request); > lo->lo_queue->queuedata = lo; > lo->lo_queue->unplug_fn = loop_unplug; > + if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op && > + file->f_op->fsync) { > + blk_queue_ordered(lo->lo_queue, QUEUE_ORDERED_DRAIN, NULL); > + } > > set_capacity(lo->lo_disk, size); > bd_set_size(bdev, size << 9);
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