| Message ID | 4C1B90AE.1050703@redhat.com |
|---|---|
| State | Rejected, archived |
| Headers | show |
On 2010-06-18 17:28, Eric Sandeen wrote: > Jens Axboe wrote: >> On 18/06/10 16.59, Eric Sandeen wrote: >> >>> Eric Sandeen wrote: >>> >>>> Jens Axboe wrote: >>>> >>>>> Hi, >>>>> >>>>> I was writing a small fio job file to do writes and read verifies on a >>>>> device. It forks 32 processes, each writing randomly to 4 files with a >>>>> block size between 4k and 16k. When it has written 1024 of those blocks, >>>>> it'll verify the oldest 512 of them. Each block is checksummed for every >>>>> 512b. It uses libaio and O_DIRECT. >>>>> >>>>> It works on ext2 and btrfs. I haven't run it to completion yet, but they >>>>> survive 15-20 minutes just fine. ext4 doesn't even go a full minutes >>>>> before this triggers: >>>>> >>>> Jens, can you try XFS too? Since ext3 can't do direct IO to a hole, >>>> (and I'm not sure about btrfs in that regard), ext4 may be most similar >>>> to xfs's behavior on the test ... wondering how it fares. >>>> >>>> Thanks, >>>> -Eric >>>> >>> Actually mingming had a patch for direct-io.c which may be related, I'll >>> test that out. >>> >> >> OK, I'll try XFS tonight as well. >> >> >> > I haven't been able to reproduce it on ext4 here, yet. > > FWIW here's the patch from mingming: > > When unaligned DIO writes, skip zero out the block if the buffer is marked > unwritten. That means there is an asynconous direct IO (append or fill the hole) > still pending. > > Signed-off-by: Mingming Cao <cmm@us.ibm.com> > --- > fs/direct-io.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > Index: linux-git/fs/direct-io.c > =================================================================== > --- linux-git.orig/fs/direct-io.c 2010-05-07 15:42:22.855033403 -0700 > +++ linux-git/fs/direct-io.c 2010-05-07 15:44:17.695007770 -0700 > @@ -740,7 +740,8 @@ > struct page *page; > > dio->start_zero_done = 1; > - if (!dio->blkfactor || !buffer_new(&dio->map_bh)) > + if (!dio->blkfactor || !buffer_new(&dio->map_bh) > + || buffer_unwritten(&dio->map_bh)) > return; > > dio_blocks_per_fs_block = 1 << dio->blkfactor; > > What is this patch against?
Jens Axboe wrote: > On 2010-06-18 17:28, Eric Sandeen wrote: >> Jens Axboe wrote: >>> On 18/06/10 16.59, Eric Sandeen wrote: >>> >>>> Eric Sandeen wrote: >>>> >>>>> Jens Axboe wrote: >>>>> >>>>>> Hi, >>>>>> >>>>>> I was writing a small fio job file to do writes and read verifies on a >>>>>> device. It forks 32 processes, each writing randomly to 4 files with a >>>>>> block size between 4k and 16k. When it has written 1024 of those blocks, >>>>>> it'll verify the oldest 512 of them. Each block is checksummed for every >>>>>> 512b. It uses libaio and O_DIRECT. >>>>>> >>>>>> It works on ext2 and btrfs. I haven't run it to completion yet, but they >>>>>> survive 15-20 minutes just fine. ext4 doesn't even go a full minutes >>>>>> before this triggers: >>>>>> >>>>> Jens, can you try XFS too? Since ext3 can't do direct IO to a hole, >>>>> (and I'm not sure about btrfs in that regard), ext4 may be most similar >>>>> to xfs's behavior on the test ... wondering how it fares. >>>>> >>>>> Thanks, >>>>> -Eric >>>>> >>>> Actually mingming had a patch for direct-io.c which may be related, I'll >>>> test that out. >>>> >>> OK, I'll try XFS tonight as well. >>> >>> >>> >> I haven't been able to reproduce it on ext4 here, yet. >> >> FWIW here's the patch from mingming: >> >> When unaligned DIO writes, skip zero out the block if the buffer is marked >> unwritten. That means there is an asynconous direct IO (append or fill the hole) >> still pending. >> >> Signed-off-by: Mingming Cao <cmm@us.ibm.com> >> --- >> fs/direct-io.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> Index: linux-git/fs/direct-io.c >> =================================================================== >> --- linux-git.orig/fs/direct-io.c 2010-05-07 15:42:22.855033403 -0700 >> +++ linux-git/fs/direct-io.c 2010-05-07 15:44:17.695007770 -0700 >> @@ -740,7 +740,8 @@ >> struct page *page; >> >> dio->start_zero_done = 1; >> - if (!dio->blkfactor || !buffer_new(&dio->map_bh)) >> + if (!dio->blkfactor || !buffer_new(&dio->map_bh) >> + || buffer_unwritten(&dio->map_bh)) >> return; >> >> dio_blocks_per_fs_block = 1 << dio->blkfactor; >> >> > > What is this patch against? > Applied to 2.6.32, seems to apply upstream as well. It hits dio_zero-block() -Eric -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 2010-06-18 20:04, Eric Sandeen wrote: > Jens Axboe wrote: >> On 2010-06-18 17:28, Eric Sandeen wrote: >>> Jens Axboe wrote: >>>> On 18/06/10 16.59, Eric Sandeen wrote: >>>> >>>>> Eric Sandeen wrote: >>>>> >>>>>> Jens Axboe wrote: >>>>>> >>>>>>> Hi, >>>>>>> >>>>>>> I was writing a small fio job file to do writes and read verifies on a >>>>>>> device. It forks 32 processes, each writing randomly to 4 files with a >>>>>>> block size between 4k and 16k. When it has written 1024 of those blocks, >>>>>>> it'll verify the oldest 512 of them. Each block is checksummed for every >>>>>>> 512b. It uses libaio and O_DIRECT. >>>>>>> >>>>>>> It works on ext2 and btrfs. I haven't run it to completion yet, but they >>>>>>> survive 15-20 minutes just fine. ext4 doesn't even go a full minutes >>>>>>> before this triggers: >>>>>>> >>>>>> Jens, can you try XFS too? Since ext3 can't do direct IO to a hole, >>>>>> (and I'm not sure about btrfs in that regard), ext4 may be most similar >>>>>> to xfs's behavior on the test ... wondering how it fares. >>>>>> >>>>>> Thanks, >>>>>> -Eric >>>>>> >>>>> Actually mingming had a patch for direct-io.c which may be related, I'll >>>>> test that out. >>>>> >>>> OK, I'll try XFS tonight as well. >>>> >>>> >>>> >>> I haven't been able to reproduce it on ext4 here, yet. >>> >>> FWIW here's the patch from mingming: >>> >>> When unaligned DIO writes, skip zero out the block if the buffer is marked >>> unwritten. That means there is an asynconous direct IO (append or fill the hole) >>> still pending. >>> >>> Signed-off-by: Mingming Cao <cmm@us.ibm.com> >>> --- >>> fs/direct-io.c | 3 ++- >>> 1 file changed, 2 insertions(+), 1 deletion(-) >>> >>> Index: linux-git/fs/direct-io.c >>> =================================================================== >>> --- linux-git.orig/fs/direct-io.c 2010-05-07 15:42:22.855033403 -0700 >>> +++ linux-git/fs/direct-io.c 2010-05-07 15:44:17.695007770 -0700 >>> @@ -740,7 +740,8 @@ >>> struct page *page; >>> >>> dio->start_zero_done = 1; >>> - if (!dio->blkfactor || !buffer_new(&dio->map_bh)) >>> + if (!dio->blkfactor || !buffer_new(&dio->map_bh) >>> + || buffer_unwritten(&dio->map_bh)) >>> return; >>> >>> dio_blocks_per_fs_block = 1 << dio->blkfactor; >>> >>> >> >> What is this patch against? >> > > Applied to 2.6.32, seems to apply upstream as well. > > It hits dio_zero-block() Irk indeed, I am blind. The patch does not fix it.
On 2010-06-18 20:14, Jens Axboe wrote: > On 2010-06-18 20:04, Eric Sandeen wrote: >> Jens Axboe wrote: >>> On 2010-06-18 17:28, Eric Sandeen wrote: >>>> Jens Axboe wrote: >>>>> On 18/06/10 16.59, Eric Sandeen wrote: >>>>> >>>>>> Eric Sandeen wrote: >>>>>> >>>>>>> Jens Axboe wrote: >>>>>>> >>>>>>>> Hi, >>>>>>>> >>>>>>>> I was writing a small fio job file to do writes and read verifies on a >>>>>>>> device. It forks 32 processes, each writing randomly to 4 files with a >>>>>>>> block size between 4k and 16k. When it has written 1024 of those blocks, >>>>>>>> it'll verify the oldest 512 of them. Each block is checksummed for every >>>>>>>> 512b. It uses libaio and O_DIRECT. >>>>>>>> >>>>>>>> It works on ext2 and btrfs. I haven't run it to completion yet, but they >>>>>>>> survive 15-20 minutes just fine. ext4 doesn't even go a full minutes >>>>>>>> before this triggers: >>>>>>>> >>>>>>> Jens, can you try XFS too? Since ext3 can't do direct IO to a hole, >>>>>>> (and I'm not sure about btrfs in that regard), ext4 may be most similar >>>>>>> to xfs's behavior on the test ... wondering how it fares. >>>>>>> >>>>>>> Thanks, >>>>>>> -Eric >>>>>>> >>>>>> Actually mingming had a patch for direct-io.c which may be related, I'll >>>>>> test that out. >>>>>> >>>>> OK, I'll try XFS tonight as well. >>>>> >>>>> >>>>> >>>> I haven't been able to reproduce it on ext4 here, yet. >>>> >>>> FWIW here's the patch from mingming: >>>> >>>> When unaligned DIO writes, skip zero out the block if the buffer is marked >>>> unwritten. That means there is an asynconous direct IO (append or fill the hole) >>>> still pending. >>>> >>>> Signed-off-by: Mingming Cao <cmm@us.ibm.com> >>>> --- >>>> fs/direct-io.c | 3 ++- >>>> 1 file changed, 2 insertions(+), 1 deletion(-) >>>> >>>> Index: linux-git/fs/direct-io.c >>>> =================================================================== >>>> --- linux-git.orig/fs/direct-io.c 2010-05-07 15:42:22.855033403 -0700 >>>> +++ linux-git/fs/direct-io.c 2010-05-07 15:44:17.695007770 -0700 >>>> @@ -740,7 +740,8 @@ >>>> struct page *page; >>>> >>>> dio->start_zero_done = 1; >>>> - if (!dio->blkfactor || !buffer_new(&dio->map_bh)) >>>> + if (!dio->blkfactor || !buffer_new(&dio->map_bh) >>>> + || buffer_unwritten(&dio->map_bh)) >>>> return; >>>> >>>> dio_blocks_per_fs_block = 1 << dio->blkfactor; >>>> >>>> >>> >>> What is this patch against? >>> >> >> Applied to 2.6.32, seems to apply upstream as well. >> >> It hits dio_zero-block() > > Irk indeed, I am blind. The patch does not fix it. So just to confirm that this isn't a new regression, 2.6.34 fails in the same way. If I change the test to make the random writes overwrite existing blocks instead of filling holes, then there are no problems either.
Index: linux-git/fs/direct-io.c =================================================================== --- linux-git.orig/fs/direct-io.c 2010-05-07 15:42:22.855033403 -0700 +++ linux-git/fs/direct-io.c 2010-05-07 15:44:17.695007770 -0700 @@ -740,7 +740,8 @@ struct page *page; dio->start_zero_done = 1; - if (!dio->blkfactor || !buffer_new(&dio->map_bh)) + if (!dio->blkfactor || !buffer_new(&dio->map_bh) + || buffer_unwritten(&dio->map_bh)) return; dio_blocks_per_fs_block = 1 << dio->blkfactor;