2019-06-07 13:16:38

by Naohiro Aota

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Subject: [PATCH 05/19] btrfs: disable direct IO in HMZONED mode

Direct write I/Os can be directed at existing extents that have already
been written. Such write requests are prohibited on host-managed zoned
block devices. So disable direct IO support for a volume with HMZONED mode
enabled.

Signed-off-by: Naohiro Aota <[email protected]>
---
fs/btrfs/inode.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 6bebc0ca751d..89542c19d09e 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8520,6 +8520,9 @@ static ssize_t check_direct_IO(struct btrfs_fs_info *fs_info,
unsigned int blocksize_mask = fs_info->sectorsize - 1;
ssize_t retval = -EINVAL;

+ if (btrfs_fs_incompat(fs_info, HMZONED))
+ goto out;
+
if (offset & blocksize_mask)
goto out;

--
2.21.0


2019-06-13 15:08:55

by Josef Bacik

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Subject: Re: [PATCH 05/19] btrfs: disable direct IO in HMZONED mode

On Fri, Jun 07, 2019 at 10:10:11PM +0900, Naohiro Aota wrote:
> Direct write I/Os can be directed at existing extents that have already
> been written. Such write requests are prohibited on host-managed zoned
> block devices. So disable direct IO support for a volume with HMZONED mode
> enabled.
>

That's only if we're nocow, so seems like you only need to disable DIO into
nocow regions with hmzoned? Thanks,

Josef

2019-06-18 08:19:59

by Naohiro Aota

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Subject: Re: [PATCH 05/19] btrfs: disable direct IO in HMZONED mode

On 2019/06/13 23:00, Josef Bacik wrote:
> On Fri, Jun 07, 2019 at 10:10:11PM +0900, Naohiro Aota wrote:
>> Direct write I/Os can be directed at existing extents that have already
>> been written. Such write requests are prohibited on host-managed zoned
>> block devices. So disable direct IO support for a volume with HMZONED mode
>> enabled.
>>
>
> That's only if we're nocow, so seems like you only need to disable DIO into
> nocow regions with hmzoned? Thanks,
>
> Josef
>

True. And actually, I had to disable or ignore BTRFS_INODE_NODATACOW on HMZONED.
I'll replace this patch with that one.
Thanks,