[PATCH] writeback: initialize inode members that track writeback history

[PATCH] writeback: initialize inode members that track writeback history

[Tahsin Erdogan]

inode struct members that track cgroup writeback information
should be reinitialized when inode gets allocated from
kmem_cache. Otherwise, their values remain and get used by the
new inode.

Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Acked-by: Tejun Heo <tj@kernel.org>
---
 fs/inode.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/inode.c b/fs/inode.c
index 9f62db3..69b8b52 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -154,6 +154,12 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
 	inode->i_rdev = 0;
 	inode->dirtied_when = 0;
 
+#ifdef CONFIG_CGROUP_WRITEBACK
+	inode->i_wb_frn_winner = 0;
+	inode->i_wb_frn_avg_time = 0;
+	inode->i_wb_frn_history = 0;
+#endif
+
 	if (security_inode_alloc(inode))
 		goto out;
 	spin_lock_init(&inode->i_lock);
-- 
2.7.0.rc3.207.g0ac5344

Re: [PATCH] writeback: initialize inode members that track writeback history

[Tejun Heo]

Hello,

On Tue, Feb 16, 2016 at 01:34:39PM -0800, Tahsin Erdogan wrote:
> inode struct members that track cgroup writeback information
> should be reinitialized when inode gets allocated from
> kmem_cache. Otherwise, their values remain and get used by the
> new inode.
> 
> Signed-off-by: Tahsin Erdogan <tahsin@google.com>
> Acked-by: Tejun Heo <tj@kernel.org>

This one should go for 4.5 and also prolly have the following tag.

Fixes: d10c80955265 ("writeback: implement foreign cgroup inode bdi_writeback switching")

Thanks.

-- 
tejun

Re: [PATCH] writeback: initialize inode members that track writeback history

[Jens Axboe]

On 02/16/2016 02:49 PM, Tejun Heo wrote:
> Hello,
>
> On Tue, Feb 16, 2016 at 01:34:39PM -0800, Tahsin Erdogan wrote:
>> inode struct members that track cgroup writeback information
>> should be reinitialized when inode gets allocated from
>> kmem_cache. Otherwise, their values remain and get used by the
>> new inode.
>>
>> Signed-off-by: Tahsin Erdogan <tahsin@google.com>
>> Acked-by: Tejun Heo <tj@kernel.org>
>
> This one should go for 4.5 and also prolly have the following tag.
>
> Fixes: d10c80955265 ("writeback: implement foreign cgroup inode bdi_writeback switching")

I've added it for 4.5 with the fixes tag.

-- 
Jens Axboe

[PATCH] writeback: initialize inode members that track writeback history

[Tahsin Erdogan]

inode struct members that track cgroup writeback information
should be reinitialized when inode gets allocated from
kmem_cache. Otherwise, their values remain and get used by the
new inode.

Signed-off-by: Tahsin Erdogan <tahsin@google.com>
---
 fs/inode.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/inode.c b/fs/inode.c
index 9f62db3..69b8b52 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -154,6 +154,12 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
 	inode->i_rdev = 0;
 	inode->dirtied_when = 0;
 
+#ifdef CONFIG_CGROUP_WRITEBACK
+	inode->i_wb_frn_winner = 0;
+	inode->i_wb_frn_avg_time = 0;
+	inode->i_wb_frn_history = 0;
+#endif
+
 	if (security_inode_alloc(inode))
 		goto out;
 	spin_lock_init(&inode->i_lock);
-- 
2.7.0.rc3.207.g0ac5344

Re: [PATCH] writeback: initialize inode members that track writeback history

[Tejun Heo]

On Tue, Feb 16, 2016 at 11:10:35AM -0800, Tahsin Erdogan wrote:
> inode struct members that track cgroup writeback information
> should be reinitialized when inode gets allocated from
> kmem_cache. Otherwise, their values remain and get used by the
> new inode.
> 
> Signed-off-by: Tahsin Erdogan <tahsin@google.com>

 Acked-by: Tejun Heo <tj@kernel.org>

It might make sense to route this through block with the other
writeback fix.  Can you please repost with Jens Axboe
<axboe@kernel.dk> cc'd?

Thanks.

-- 
tejun