* [PATCH] btrfs: use list_for_each_entry_safe() when delete items
@ 2013-09-01 10:19 Azat Khuzhin
0 siblings, 0 replies; 6+ messages in thread
From: Azat Khuzhin @ 2013-09-01 10:19 UTC (permalink / raw)
To: linux-btrfs; +Cc: jbacik, miaox, Azat Khuzhin, Chris Mason, open list
Replace list_for_each_entry() by list_for_each_entry_safe() in
__btrfs_close_devices()
list_for_each_entry() {
list_replace_rcu();
call_rcu(); <-- We may free the device, if we get next
device by the current one, the page fault
may happen.
}
Signed-off-by: Azat Khuzhin <a3at.mail@gmail.com>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
---
V2: Add some comments from Miao into commit message
fs/btrfs/volumes.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 78b8717..1d1b595 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -616,13 +616,13 @@ static void free_device(struct rcu_head *head)
static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
{
- struct btrfs_device *device;
+ struct btrfs_device *device, *next;
if (--fs_devices->opened > 0)
return 0;
mutex_lock(&fs_devices->device_list_mutex);
- list_for_each_entry(device, &fs_devices->devices, dev_list) {
+ list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
struct btrfs_device *new_device;
struct rcu_string *name;
--
1.7.10.4
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH] btrfs: use list_for_each_entry_safe() when delete items
@ 2013-07-27 10:12 Azat Khuzhin
2013-07-29 7:48 ` Azat Khuzhin
0 siblings, 1 reply; 6+ messages in thread
From: Azat Khuzhin @ 2013-07-27 10:12 UTC (permalink / raw)
To: linux-btrfs; +Cc: chris.mason, Azat Khuzhin, open list
Replace list_for_each_entry() by list_for_each_entry_safe() in
__btrfs_close_devices()
There is another place that delete items lock_stripe_add(), but there we
don't need safe version, because after deleting we exit from loop.
Signed-off-by: Azat Khuzhin <a3at.mail@gmail.com>
---
fs/btrfs/volumes.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 78b8717..1d1b595 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -616,13 +616,13 @@ static void free_device(struct rcu_head *head)
static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
{
- struct btrfs_device *device;
+ struct btrfs_device *device, *next;
if (--fs_devices->opened > 0)
return 0;
mutex_lock(&fs_devices->device_list_mutex);
- list_for_each_entry(device, &fs_devices->devices, dev_list) {
+ list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
struct btrfs_device *new_device;
struct rcu_string *name;
--
1.7.10.4
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] btrfs: use list_for_each_entry_safe() when delete items
2013-07-27 10:12 Azat Khuzhin
@ 2013-07-29 7:48 ` Azat Khuzhin
2013-07-30 3:40 ` Miao Xie
0 siblings, 1 reply; 6+ messages in thread
From: Azat Khuzhin @ 2013-07-29 7:48 UTC (permalink / raw)
To: linux-btrfs; +Cc: chris.mason, Azat Khuzhin, open list
On Sat, Jul 27, 2013 at 2:12 PM, Azat Khuzhin <a3at.mail@gmail.com> wrote:
> Replace list_for_each_entry() by list_for_each_entry_safe() in
> __btrfs_close_devices()
>
> There is another place that delete items lock_stripe_add(), but there we
> don't need safe version, because after deleting we exit from loop.
>
> Signed-off-by: Azat Khuzhin <a3at.mail@gmail.com>
> ---
> fs/btrfs/volumes.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index 78b8717..1d1b595 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -616,13 +616,13 @@ static void free_device(struct rcu_head *head)
>
> static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
> {
> - struct btrfs_device *device;
> + struct btrfs_device *device, *next;
>
> if (--fs_devices->opened > 0)
> return 0;
>
> mutex_lock(&fs_devices->device_list_mutex);
> - list_for_each_entry(device, &fs_devices->devices, dev_list) {
> + list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
> struct btrfs_device *new_device;
> struct rcu_string *name;
There is "kfree(device);" at the end of loop, maybe there must "goto
again;" after it?
(instead of this patch)
>
> --
> 1.7.10.4
>
--
Respectfully
Azat Khuzhin
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] btrfs: use list_for_each_entry_safe() when delete items
2013-07-29 7:48 ` Azat Khuzhin
@ 2013-07-30 3:40 ` Miao Xie
2013-08-31 6:11 ` Azat Khuzhin
0 siblings, 1 reply; 6+ messages in thread
From: Miao Xie @ 2013-07-30 3:40 UTC (permalink / raw)
To: Azat Khuzhin; +Cc: linux-btrfs, chris.mason, open list
On mon, 29 Jul 2013 11:48:32 +0400, Azat Khuzhin wrote:
> On Sat, Jul 27, 2013 at 2:12 PM, Azat Khuzhin <a3at.mail@gmail.com> wrote:
>> Replace list_for_each_entry() by list_for_each_entry_safe() in
>> __btrfs_close_devices()
>>
>> There is another place that delete items lock_stripe_add(), but there we
>> don't need safe version, because after deleting we exit from loop.
>>
>> Signed-off-by: Azat Khuzhin <a3at.mail@gmail.com>
>> ---
>> fs/btrfs/volumes.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
>> index 78b8717..1d1b595 100644
>> --- a/fs/btrfs/volumes.c
>> +++ b/fs/btrfs/volumes.c
>> @@ -616,13 +616,13 @@ static void free_device(struct rcu_head *head)
>>
>> static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
>> {
>> - struct btrfs_device *device;
>> + struct btrfs_device *device, *next;
>>
>> if (--fs_devices->opened > 0)
>> return 0;
>>
>> mutex_lock(&fs_devices->device_list_mutex);
>> - list_for_each_entry(device, &fs_devices->devices, dev_list) {
>> + list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
>> struct btrfs_device *new_device;
>> struct rcu_string *name;
>
> There is "kfree(device);" at the end of loop, maybe there must "goto
> again;" after it?
> (instead of this patch)
Your fix is right, we needn't search from the head once again.
The other fix way is:
call_rcu(&device->rcu, free_device);
+ device = new_device;
}
but from the viewpoint of the readability, this way is not so good.
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
>
>>
>> --
>> 1.7.10.4
>>
>
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] btrfs: use list_for_each_entry_safe() when delete items
2013-07-30 3:40 ` Miao Xie
@ 2013-08-31 6:11 ` Azat Khuzhin
0 siblings, 0 replies; 6+ messages in thread
From: Azat Khuzhin @ 2013-08-31 6:11 UTC (permalink / raw)
To: miaox; +Cc: linux-btrfs, chris.mason, open list
On Tue, Jul 30, 2013 at 7:40 AM, Miao Xie <miaox@cn.fujitsu.com> wrote:
> On mon, 29 Jul 2013 11:48:32 +0400, Azat Khuzhin wrote:
>> On Sat, Jul 27, 2013 at 2:12 PM, Azat Khuzhin <a3at.mail@gmail.com> wrote:
>>> Replace list_for_each_entry() by list_for_each_entry_safe() in
>>> __btrfs_close_devices()
>>>
>>> There is another place that delete items lock_stripe_add(), but there we
>>> don't need safe version, because after deleting we exit from loop.
>>>
>>> Signed-off-by: Azat Khuzhin <a3at.mail@gmail.com>
>>> ---
>>> fs/btrfs/volumes.c | 4 ++--
>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
>>> index 78b8717..1d1b595 100644
>>> --- a/fs/btrfs/volumes.c
>>> +++ b/fs/btrfs/volumes.c
>>> @@ -616,13 +616,13 @@ static void free_device(struct rcu_head *head)
>>>
>>> static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
>>> {
>>> - struct btrfs_device *device;
>>> + struct btrfs_device *device, *next;
>>>
>>> if (--fs_devices->opened > 0)
>>> return 0;
>>>
>>> mutex_lock(&fs_devices->device_list_mutex);
>>> - list_for_each_entry(device, &fs_devices->devices, dev_list) {
>>> + list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
>>> struct btrfs_device *new_device;
>>> struct rcu_string *name;
>>
>> There is "kfree(device);" at the end of loop, maybe there must "goto
>> again;" after it?
>> (instead of this patch)
Ugh. I was looking into another function!
>
> Your fix is right, we needn't search from the head once again.
>
> The other fix way is:
> call_rcu(&device->rcu, free_device);
> + device = new_device;
> }
> but from the viewpoint of the readability, this way is not so good.
>
> Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Thanks!
Miao, should I resend patch with you reviewed-by?
>
>>
>>>
>>> --
>>> 1.7.10.4
>>>
>>
>>
>>
>
--
Respectfully
Azat Khuzhin
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH] btrfs: use list_for_each_entry_safe() when delete items
@ 2013-07-27 5:15 Azat Khuzhin
0 siblings, 0 replies; 6+ messages in thread
From: Azat Khuzhin @ 2013-07-27 5:15 UTC (permalink / raw)
To: linux-btrfs; +Cc: chris.mason, Azat Khuzhin, open list
Replace list_for_each_entry() by list_for_each_entry_safe() in next
functions:
- lock_stripe_add()
- __btrfs_close_devices()
Signed-off-by: Azat Khuzhin <a3at.mail@gmail.com>
---
fs/btrfs/raid56.c | 4 ++--
fs/btrfs/volumes.c | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 0525e13..37e6dc9 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -636,7 +636,7 @@ static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
{
int bucket = rbio_bucket(rbio);
struct btrfs_stripe_hash *h = rbio->fs_info->stripe_hash_table->table + bucket;
- struct btrfs_raid_bio *cur;
+ struct btrfs_raid_bio *cur, *next;
struct btrfs_raid_bio *pending;
unsigned long flags;
DEFINE_WAIT(wait);
@@ -646,7 +646,7 @@ static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
int walk = 0;
spin_lock_irqsave(&h->lock, flags);
- list_for_each_entry(cur, &h->hash_list, hash_list) {
+ list_for_each_entry_safe(cur, next, &h->hash_list, hash_list) {
walk++;
if (cur->raid_map[0] == rbio->raid_map[0]) {
spin_lock(&cur->bio_list_lock);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 78b8717..1d1b595 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -616,13 +616,13 @@ static void free_device(struct rcu_head *head)
static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
{
- struct btrfs_device *device;
+ struct btrfs_device *device, *next;
if (--fs_devices->opened > 0)
return 0;
mutex_lock(&fs_devices->device_list_mutex);
- list_for_each_entry(device, &fs_devices->devices, dev_list) {
+ list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
struct btrfs_device *new_device;
struct rcu_string *name;
--
1.7.10.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
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2013-09-01 10:19 [PATCH] btrfs: use list_for_each_entry_safe() when delete items Azat Khuzhin
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2013-07-27 10:12 Azat Khuzhin
2013-07-29 7:48 ` Azat Khuzhin
2013-07-30 3:40 ` Miao Xie
2013-08-31 6:11 ` Azat Khuzhin
2013-07-27 5:15 Azat Khuzhin
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