* [PATCH] btrfs: remove warnings superseded by refcount_t usage
@ 2018-06-25 16:38 David Sterba
2018-06-26 14:00 ` Nikolay Borisov
0 siblings, 1 reply; 4+ messages in thread
From: David Sterba @ 2018-06-25 16:38 UTC (permalink / raw)
To: linux-btrfs; +Cc: David Sterba
There are several WARN_ON calls that catch incrorrect reference counter
updates, but this is what the refcount_t does already:
* refcount_inc from 0 will warn
* refcount_dec_and_test from 0 will warn
Signed-off-by: David Sterba <dsterba@suse.com>
---
fs/btrfs/delayed-ref.h | 1 -
fs/btrfs/extent_map.c | 2 +-
fs/btrfs/transaction.c | 1 -
fs/btrfs/volumes.c | 1 -
4 files changed, 1 insertion(+), 4 deletions(-)
diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
index ea1aecb6a50d..16ee92c541bf 100644
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -210,7 +210,6 @@ btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op)
static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
{
- WARN_ON(refcount_read(&ref->refs) == 0);
if (refcount_dec_and_test(&ref->refs)) {
WARN_ON(ref->in_tree);
switch (ref->type) {
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 6648d55e5339..6808ad4ed3c9 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -72,7 +72,7 @@ void free_extent_map(struct extent_map *em)
{
if (!em)
return;
- WARN_ON(refcount_read(&em->refs) == 0);
+
if (refcount_dec_and_test(&em->refs)) {
WARN_ON(extent_map_in_tree(em));
WARN_ON(!list_empty(&em->list));
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 4485eae41e88..f6b68099b767 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -41,7 +41,6 @@ static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
void btrfs_put_transaction(struct btrfs_transaction *transaction)
{
- WARN_ON(refcount_read(&transaction->use_count) == 0);
if (refcount_dec_and_test(&transaction->use_count)) {
BUG_ON(!list_empty(&transaction->list));
WARN_ON(!RB_EMPTY_ROOT(&transaction->delayed_refs.href_root));
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index e034ad9e23b4..f64d26b4f278 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -5330,7 +5330,6 @@ static struct btrfs_bio *alloc_btrfs_bio(int total_stripes, int real_stripes)
void btrfs_get_bbio(struct btrfs_bio *bbio)
{
- WARN_ON(!refcount_read(&bbio->refs));
refcount_inc(&bbio->refs);
}
--
2.17.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] btrfs: remove warnings superseded by refcount_t usage
2018-06-25 16:38 [PATCH] btrfs: remove warnings superseded by refcount_t usage David Sterba
@ 2018-06-26 14:00 ` Nikolay Borisov
2018-06-29 14:05 ` David Sterba
0 siblings, 1 reply; 4+ messages in thread
From: Nikolay Borisov @ 2018-06-26 14:00 UTC (permalink / raw)
To: David Sterba, linux-btrfs
On 25.06.2018 19:38, David Sterba wrote:
> There are several WARN_ON calls that catch incrorrect reference counter
> updates, but this is what the refcount_t does already:
>
> * refcount_inc from 0 will warn
> * refcount_dec_and_test from 0 will warn
>
But these warnings are only going to be triggered in the case of
CONFIG_REFCOUNT_FULL otherwise refcount falls back to plain atomic
operations.
> Signed-off-by: David Sterba <dsterba@suse.com>
> ---
> fs/btrfs/delayed-ref.h | 1 -
> fs/btrfs/extent_map.c | 2 +-
> fs/btrfs/transaction.c | 1 -
> fs/btrfs/volumes.c | 1 -
> 4 files changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
> index ea1aecb6a50d..16ee92c541bf 100644
> --- a/fs/btrfs/delayed-ref.h
> +++ b/fs/btrfs/delayed-ref.h
> @@ -210,7 +210,6 @@ btrfs_free_delayed_extent_op(struct btrfs_delayed_extent_op *op)
>
> static inline void btrfs_put_delayed_ref(struct btrfs_delayed_ref_node *ref)
> {
> - WARN_ON(refcount_read(&ref->refs) == 0);
> if (refcount_dec_and_test(&ref->refs)) {
> WARN_ON(ref->in_tree);
> switch (ref->type) {
> diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
> index 6648d55e5339..6808ad4ed3c9 100644
> --- a/fs/btrfs/extent_map.c
> +++ b/fs/btrfs/extent_map.c
> @@ -72,7 +72,7 @@ void free_extent_map(struct extent_map *em)
> {
> if (!em)
> return;
> - WARN_ON(refcount_read(&em->refs) == 0);
> +
> if (refcount_dec_and_test(&em->refs)) {
> WARN_ON(extent_map_in_tree(em));
> WARN_ON(!list_empty(&em->list));
> diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
> index 4485eae41e88..f6b68099b767 100644
> --- a/fs/btrfs/transaction.c
> +++ b/fs/btrfs/transaction.c
> @@ -41,7 +41,6 @@ static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
>
> void btrfs_put_transaction(struct btrfs_transaction *transaction)
> {
> - WARN_ON(refcount_read(&transaction->use_count) == 0);
> if (refcount_dec_and_test(&transaction->use_count)) {
> BUG_ON(!list_empty(&transaction->list));
> WARN_ON(!RB_EMPTY_ROOT(&transaction->delayed_refs.href_root));
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index e034ad9e23b4..f64d26b4f278 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -5330,7 +5330,6 @@ static struct btrfs_bio *alloc_btrfs_bio(int total_stripes, int real_stripes)
>
> void btrfs_get_bbio(struct btrfs_bio *bbio)
> {
> - WARN_ON(!refcount_read(&bbio->refs));
> refcount_inc(&bbio->refs);
> }
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] btrfs: remove warnings superseded by refcount_t usage
2018-06-26 14:00 ` Nikolay Borisov
@ 2018-06-29 14:05 ` David Sterba
2018-07-05 15:55 ` David Sterba
0 siblings, 1 reply; 4+ messages in thread
From: David Sterba @ 2018-06-29 14:05 UTC (permalink / raw)
To: Nikolay Borisov; +Cc: David Sterba, linux-btrfs
On Tue, Jun 26, 2018 at 05:00:46PM +0300, Nikolay Borisov wrote:
> On 25.06.2018 19:38, David Sterba wrote:
> > There are several WARN_ON calls that catch incrorrect reference counter
> > updates, but this is what the refcount_t does already:
> >
> > * refcount_inc from 0 will warn
> > * refcount_dec_and_test from 0 will warn
> >
>
> But these warnings are only going to be triggered in the case of
> CONFIG_REFCOUNT_FULL otherwise refcount falls back to plain atomic
> operations.
Right, I'm for REFCOUNT_FULL on by default obviously, but we need to
take handle the case where it's not. And there isn't a refcount type
with the full semantics.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] btrfs: remove warnings superseded by refcount_t usage
2018-06-29 14:05 ` David Sterba
@ 2018-07-05 15:55 ` David Sterba
0 siblings, 0 replies; 4+ messages in thread
From: David Sterba @ 2018-07-05 15:55 UTC (permalink / raw)
To: dsterba, Nikolay Borisov, David Sterba, linux-btrfs
On Fri, Jun 29, 2018 at 04:05:40PM +0200, David Sterba wrote:
> On Tue, Jun 26, 2018 at 05:00:46PM +0300, Nikolay Borisov wrote:
> > On 25.06.2018 19:38, David Sterba wrote:
> > > There are several WARN_ON calls that catch incrorrect reference counter
> > > updates, but this is what the refcount_t does already:
> > >
> > > * refcount_inc from 0 will warn
> > > * refcount_dec_and_test from 0 will warn
> > >
> >
> > But these warnings are only going to be triggered in the case of
> > CONFIG_REFCOUNT_FULL otherwise refcount falls back to plain atomic
> > operations.
>
> Right, I'm for REFCOUNT_FULL on by default obviously, but we need to
> take handle the case where it's not. And there isn't a refcount type
> with the full semantics.
There refcount helpers will be extended to allow the full check
semantics so I'll use them and drop the WARN_ONs once the patch gets
merged.
https://lore.kernel.org/lkml/20180703100102.16615-1-mark.rutland@arm.com/
^ permalink raw reply [flat|nested] 4+ messages in thread
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2018-06-25 16:38 [PATCH] btrfs: remove warnings superseded by refcount_t usage David Sterba
2018-06-26 14:00 ` Nikolay Borisov
2018-06-29 14:05 ` David Sterba
2018-07-05 15:55 ` David Sterba
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