* [Ocfs2-devel] [PATCH 1/4] lockres_seq_next should increase position index
[not found] <ca1497b7-6a6e-8043-63c7-b17c094ebc05@virtuozzo.com>
@ 2020-01-26 2:21 ` Joseph Qi
2020-02-26 6:52 ` [Ocfs2-devel] [PATCH v2 0/4] ocfs2: seq_file .next functions " Vasily Averin
` (4 more replies)
0 siblings, 5 replies; 15+ messages in thread
From: Joseph Qi @ 2020-01-26 2:21 UTC (permalink / raw)
To: ocfs2-devel
On 20/1/23 15:39, Vasily Averin wrote:
> if seq_file .next fuction does not change position index,
> read after some lseek can generate unexpected output.
>
> https://urldefense.proofpoint.com/v2/url?u=https-3A__bugzilla.kernel.org_show-5Fbug.cgi-3Fid-3D206283&d=DwICaQ&c=RoP1YumCXCgaWHvlZYR8PZh8Bv7qIrMUB65eapI_JnE&r=C7gAd4uDxlAvTdc0vmU6X8CMk6L2iDY8-HD0qT6Fo7Y&m=lFWWo4w3KGQSd5EANoUFCp9aybqo1xeFs5MD0dgTnkA&s=dFZ-8He72Ffi8NGZB7iFik1nYOMs9wfzjDFpATCr72I&e=
> Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
We'd better add the missing tag:
Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface")
> ---
> fs/ocfs2/dlm/dlmdebug.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/fs/ocfs2/dlm/dlmdebug.c b/fs/ocfs2/dlm/dlmdebug.c
> index 4d0b452..08a19c9 100644
> --- a/fs/ocfs2/dlm/dlmdebug.c
> +++ b/fs/ocfs2/dlm/dlmdebug.c
> @@ -590,6 +590,7 @@ static void lockres_seq_stop(struct seq_file *m, void *v)
>
> static void *lockres_seq_next(struct seq_file *m, void *v, loff_t *pos)
> {
> + (*pos)++;
> return NULL;
> }
>
>
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Ocfs2-devel] [PATCH v2 0/4] ocfs2: seq_file .next functions should increase position index
2020-01-26 2:21 ` [Ocfs2-devel] [PATCH 1/4] lockres_seq_next should increase position index Joseph Qi
@ 2020-02-26 6:52 ` Vasily Averin
2020-02-26 8:32 ` Joseph Qi
2020-02-26 6:53 ` [Ocfs2-devel] [PATCH v2 1/4] lockres_seq_next should increase " Vasily Averin
` (3 subsequent siblings)
4 siblings, 1 reply; 15+ messages in thread
From: Vasily Averin @ 2020-02-26 6:52 UTC (permalink / raw)
To: ocfs2-devel
v2: resend with improved patch description
In Aug 2018 NeilBrown noticed
commit 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface")
"Some ->next functions do not increment *pos when they return NULL...
Note that such ->next functions are buggy and should be fixed.
A simple demonstration is
dd if=/proc/swaps bs=1000 skip=1
Choose any block size larger than the size of /proc/swaps. This will
always show the whole last line of /proc/swaps"
/proc/swaps output was fixed recently, however there are lot of other
affected files and 4 of them are related to ocfs2.
Unfortunately I'm not familiar with ocfs2 and cannot verify the patches locally.
Usually you can observe following related problems:
- read after lseek beyond end of file, described above by NeilBrown
"dd if=<AFFECTED_FILE> bs=1000 skip=1" will incorrectly generate whole last line
- read after lseek on into middle of last line will output expected rest of
last line but then repeat whole last line once again.
- If .show() function generates multi-line output following bash script will never finish.
$ q=;while read -r r;do echo "$((++q)) $r";done < AFFECTED_FILE
Link: https://urldefense.com/v3/__https://bugzilla.kernel.org/show_bug.cgi?id=206283__;!!GqivPVa7Brio!Jq0fspl3uRa_Xiu-ifjc60ajewi308CVdv8Dq-9kHzOjkRYAd1YKlDU1a1TQdmMTBPWO8g$
Vasily Averin (4):
lockres_seq_next should increase position index
ocfs2_dlm_seq_next should increase position index
nst_seq_next should increase position index
sc_seq_next should increase position index
fs/ocfs2/cluster/netdebug.c | 2 ++
fs/ocfs2/dlm/dlmdebug.c | 1 +
fs/ocfs2/dlmglue.c | 1 +
3 files changed, 4 insertions(+)
--
1.8.3.1
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Ocfs2-devel] [PATCH v2 1/4] lockres_seq_next should increase position index
2020-01-26 2:21 ` [Ocfs2-devel] [PATCH 1/4] lockres_seq_next should increase position index Joseph Qi
2020-02-26 6:52 ` [Ocfs2-devel] [PATCH v2 0/4] ocfs2: seq_file .next functions " Vasily Averin
@ 2020-02-26 6:53 ` Vasily Averin
2020-02-26 6:53 ` [Ocfs2-devel] [PATCH v2 2/4] ocfs2_dlm_seq_next " Vasily Averin
` (2 subsequent siblings)
4 siblings, 0 replies; 15+ messages in thread
From: Vasily Averin @ 2020-02-26 6:53 UTC (permalink / raw)
To: ocfs2-devel
If .next function does not change position index,
following .show function will repeat output related
to current position index.
Cc: stable at vger.kernel.org
Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code ...")
Link: https://urldefense.com/v3/__https://bugzilla.kernel.org/show_bug.cgi?id=206283__;!!GqivPVa7Brio!L2HMxpDQh7db9dQNbu_Tp0uSxEzRVFvZ0bxczbKOsvt3hiKOnWevYToiSclR_wkhhve7qA$
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
---
fs/ocfs2/dlm/dlmdebug.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/ocfs2/dlm/dlmdebug.c b/fs/ocfs2/dlm/dlmdebug.c
index c5c6efb..3e395cd 100644
--- a/fs/ocfs2/dlm/dlmdebug.c
+++ b/fs/ocfs2/dlm/dlmdebug.c
@@ -590,6 +590,7 @@ static void lockres_seq_stop(struct seq_file *m, void *v)
static void *lockres_seq_next(struct seq_file *m, void *v, loff_t *pos)
{
+ (*pos)++;
return NULL;
}
--
1.8.3.1
^ permalink raw reply related [flat|nested] 15+ messages in thread
* [Ocfs2-devel] [PATCH v2 2/4] ocfs2_dlm_seq_next should increase position index
2020-01-26 2:21 ` [Ocfs2-devel] [PATCH 1/4] lockres_seq_next should increase position index Joseph Qi
2020-02-26 6:52 ` [Ocfs2-devel] [PATCH v2 0/4] ocfs2: seq_file .next functions " Vasily Averin
2020-02-26 6:53 ` [Ocfs2-devel] [PATCH v2 1/4] lockres_seq_next should increase " Vasily Averin
@ 2020-02-26 6:53 ` Vasily Averin
2020-02-26 6:53 ` [Ocfs2-devel] [PATCH v2 3/4] nst_seq_next " Vasily Averin
2020-02-26 6:54 ` [Ocfs2-devel] [PATCH v2 4/4] sc_seq_next " Vasily Averin
4 siblings, 0 replies; 15+ messages in thread
From: Vasily Averin @ 2020-02-26 6:53 UTC (permalink / raw)
To: ocfs2-devel
If .next function does not change position index,
following .show function will repeat output related
to current position index.
Cc: stable at vger.kernel.org
Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code ...")
Link: https://urldefense.com/v3/__https://bugzilla.kernel.org/show_bug.cgi?id=206283__;!!GqivPVa7Brio!MSixDxrphasW57tPl4VD6FKe6ZxcdQkP0oN-cWbZFdRxlNR1AOaFgm3-OunznZSXFEf0Nw$
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
---
fs/ocfs2/dlmglue.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index cb9e6a7..170eb75 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -3080,6 +3080,7 @@ static void *ocfs2_dlm_seq_next(struct seq_file *m, void *v, loff_t *pos)
struct ocfs2_lock_res *iter = v;
struct ocfs2_lock_res *dummy = &priv->p_iter_res;
+ (*pos)++;
spin_lock(&ocfs2_dlm_tracking_lock);
iter = ocfs2_dlm_next_res(iter, priv);
list_del_init(&dummy->l_debug_list);
--
1.8.3.1
^ permalink raw reply related [flat|nested] 15+ messages in thread
* [Ocfs2-devel] [PATCH v2 3/4] nst_seq_next should increase position index
2020-01-26 2:21 ` [Ocfs2-devel] [PATCH 1/4] lockres_seq_next should increase position index Joseph Qi
` (2 preceding siblings ...)
2020-02-26 6:53 ` [Ocfs2-devel] [PATCH v2 2/4] ocfs2_dlm_seq_next " Vasily Averin
@ 2020-02-26 6:53 ` Vasily Averin
2020-02-26 6:54 ` [Ocfs2-devel] [PATCH v2 4/4] sc_seq_next " Vasily Averin
4 siblings, 0 replies; 15+ messages in thread
From: Vasily Averin @ 2020-02-26 6:53 UTC (permalink / raw)
To: ocfs2-devel
If .next function does not change position index,
following .show function will repeat output related
to current position index.
Cc: stable at vger.kernel.org
Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code ...")
Link: https://urldefense.com/v3/__https://bugzilla.kernel.org/show_bug.cgi?id=206283__;!!GqivPVa7Brio!PE9FFsjnlLuJDzt36R28ZRQGJ-jhWo4rlejw_3MAX2zd1KvSlIomyKIzzBvc5psf88EhGw$
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
---
fs/ocfs2/cluster/netdebug.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/ocfs2/cluster/netdebug.c b/fs/ocfs2/cluster/netdebug.c
index 02bf4a1..26fc6a2 100644
--- a/fs/ocfs2/cluster/netdebug.c
+++ b/fs/ocfs2/cluster/netdebug.c
@@ -97,6 +97,7 @@ static void *nst_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct o2net_send_tracking *nst, *dummy_nst = seq->private;
+ ++(*pos);
spin_lock(&o2net_debug_lock);
nst = next_nst(dummy_nst);
list_del_init(&dummy_nst->st_net_debug_item);
--
1.8.3.1
^ permalink raw reply related [flat|nested] 15+ messages in thread
* [Ocfs2-devel] [PATCH v2 4/4] sc_seq_next should increase position index
2020-01-26 2:21 ` [Ocfs2-devel] [PATCH 1/4] lockres_seq_next should increase position index Joseph Qi
` (3 preceding siblings ...)
2020-02-26 6:53 ` [Ocfs2-devel] [PATCH v2 3/4] nst_seq_next " Vasily Averin
@ 2020-02-26 6:54 ` Vasily Averin
4 siblings, 0 replies; 15+ messages in thread
From: Vasily Averin @ 2020-02-26 6:54 UTC (permalink / raw)
To: ocfs2-devel
If .next function does not change position index,
following .show function will repeat output related
to current position index.
Cc: stable at vger.kernel.org
Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code ...")
Link: https://urldefense.com/v3/__https://bugzilla.kernel.org/show_bug.cgi?id=206283__;!!GqivPVa7Brio!OngcjY3Xm--sW3K-NHZ9tpRCS9bSp-bm45QwSwULt5bj3vAbmwAs1_LXYQm9uQ3rK7wmDA$
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
---
fs/ocfs2/cluster/netdebug.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/ocfs2/cluster/netdebug.c b/fs/ocfs2/cluster/netdebug.c
index 26fc6a2..71ddd65 100644
--- a/fs/ocfs2/cluster/netdebug.c
+++ b/fs/ocfs2/cluster/netdebug.c
@@ -251,6 +251,7 @@ static void *sc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
struct o2net_sock_debug *sd = seq->private;
struct o2net_sock_container *sc, *dummy_sc = sd->dbg_sock;
+ ++(*pos);
spin_lock(&o2net_debug_lock);
sc = next_sc(dummy_sc);
list_del_init(&dummy_sc->sc_net_debug_item);
--
1.8.3.1
^ permalink raw reply related [flat|nested] 15+ messages in thread
* [Ocfs2-devel] [PATCH v2 0/4] ocfs2: seq_file .next functions should increase position index
2020-02-26 6:52 ` [Ocfs2-devel] [PATCH v2 0/4] ocfs2: seq_file .next functions " Vasily Averin
@ 2020-02-26 8:32 ` Joseph Qi
2020-03-09 11:32 ` piaojun
[not found] ` <e954f783-5a1c-8847-7b0d-298825ee06a4@huawei.com>
0 siblings, 2 replies; 15+ messages in thread
From: Joseph Qi @ 2020-02-26 8:32 UTC (permalink / raw)
To: ocfs2-devel
Looks good.
Jun, could you please help verify these changes and give your tested-by?
Since I don't have ocfs2 cluster locally...
Thanks,
Joseph
On 2020/2/26 14:52, Vasily Averin wrote:
> v2: resend with improved patch description
>
> In Aug 2018 NeilBrown noticed
> commit 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface")
> "Some ->next functions do not increment *pos when they return NULL...
> Note that such ->next functions are buggy and should be fixed.
> A simple demonstration is
>
> dd if=/proc/swaps bs=1000 skip=1
>
> Choose any block size larger than the size of /proc/swaps. This will
> always show the whole last line of /proc/swaps"
>
> /proc/swaps output was fixed recently, however there are lot of other
> affected files and 4 of them are related to ocfs2.
>
> Unfortunately I'm not familiar with ocfs2 and cannot verify the patches locally.
>
> Usually you can observe following related problems:
> - read after lseek beyond end of file, described above by NeilBrown
> "dd if=<AFFECTED_FILE> bs=1000 skip=1" will incorrectly generate whole last line
>
> - read after lseek on into middle of last line will output expected rest of
> last line but then repeat whole last line once again.
>
> - If .show() function generates multi-line output following bash script will never finish.
>
> $ q=;while read -r r;do echo "$((++q)) $r";done < AFFECTED_FILE
>
> Link: https://urldefense.com/v3/__https://bugzilla.kernel.org/show_bug.cgi?id=206283__;!!GqivPVa7Brio!MWBujxdP_p0jZT4u4PHj-NBdhW4f9I2yRxwrFk8cG8MMHecBByM6r53K0M3eU9W5Oe1rdQ$
>
> Vasily Averin (4):
> lockres_seq_next should increase position index
> ocfs2_dlm_seq_next should increase position index
> nst_seq_next should increase position index
> sc_seq_next should increase position index
>
> fs/ocfs2/cluster/netdebug.c | 2 ++
> fs/ocfs2/dlm/dlmdebug.c | 1 +
> fs/ocfs2/dlmglue.c | 1 +
> 3 files changed, 4 insertions(+)
>
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Ocfs2-devel] [PATCH v2 0/4] ocfs2: seq_file .next functions should increase position index
2020-02-26 8:32 ` Joseph Qi
@ 2020-03-09 11:32 ` piaojun
[not found] ` <e954f783-5a1c-8847-7b0d-298825ee06a4@huawei.com>
1 sibling, 0 replies; 15+ messages in thread
From: piaojun @ 2020-03-09 11:32 UTC (permalink / raw)
To: ocfs2-devel
On 2020/2/26 16:32, Joseph Qi wrote:
> Looks good.
> Jun, could you please help verify these changes and give your tested-by?
> Since I don't have ocfs2 cluster locally...
OK, Shan will help testing this patch and give a 'tested-by' later.
Jun
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Ocfs2-devel] Fwd: Re: [PATCH v2 0/4] ocfs2: seq_file .next functions should increase position index
[not found] ` <e954f783-5a1c-8847-7b0d-298825ee06a4@huawei.com>
@ 2020-03-21 4:24 ` lishan
2020-03-22 7:27 ` Vasily Averin
0 siblings, 1 reply; 15+ messages in thread
From: lishan @ 2020-03-21 4:24 UTC (permalink / raw)
To: ocfs2-devel
test environment:
kernel version: 5.6.0-rc5
lockres_seq_next -->
/sys/kernel/debug/o2dlm/2C9B43EBE44D4715A0B0DBE4D72016A3/locking_state
The output content is incomplete and endless, and the subsequent output is skip reading.
The operation and print is as follows:
dd if=/sys/kernel/debug/o2dlm/2C9B43EBE44D4715A0B0DBE4D72016A3/locking_state bs=40 skip=1
S:1,5,0,0,0,0,0,0,0,0,3
RMAP:
LVBX:00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
LOCK:1,0,5,-1,5,5:1,0,0,0,0,0,0,0,0,2
NAME:M0000000000000000000042e7349704
LRES:1,5,0,0,0,0,0,0,0,0,3
RMAP:
LVBX:00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
LOCK:1,0,5,-1,5,5:2,0,0,0,0,0,0,0,0,2
........
NAME:M0000000000000000000042e7349704
LRES:1,5,0,0,0,0,0,0,0,0,3
RMAP:
LVBX:00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
LOCK:1,0,5,-1,5,5:2,0,0,0,0,0,0,0,0,2
NAME:M0000000000000000000010e7349704
......
but, there is no endless output using the following script:
linux-EalnPD:~ # q=;while read -r r;do echo "$((++q)) $r";done < /sys/kernel/debug/o2dlm/2C9B43EBE44D4715A0B0DBE4D72016A3/locking_state
1 NAME:S000000000000000000000200000000
2 LRES:1,5,0,0,0,0,0,0,0,0,3
3 RMAP:
4 LVBX:00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
5 LOCK:1,0,5,-1,5,5:6,0,0,0,0,0,0,0,0,2
6
7
8 NAME:M0000000000000000000016e7349704
9 NAME:M0000000000000000000018e7349704
10 NAME:M000000000000000000001ae7349704
11 NAME:M000000000000000000001ce7349704
12 NAME:M000000000000000000001ee7349704
13 NAME:M0000000000000000000020e7349704
....
534 NAME:W00000000000000000843c81d0b7768
535 NAME:O00000000000000000843c800000000
Other interface test results:
nst_seq_next --> /sys/kernel/debug/o2net/send_tracking
sc_seq_next --> /sys/kernel/debug/o2net/stats
File content is empty, so, read it like use dd command, No effect.
ocfs2_dlm_seq_next -->
/sys/kernel/debug/ocfs2/2C9B43EBE44D4715A0B0DBE4D72016A3/locking_state
Read file normal output.
And, output is still endless, after adding Vasily Averin's modifications, patch are as follow:
[Ocfs2-devel] [PATCH v2 1/4] lockres_seq_next should increase position index Vasily Averin
[Ocfs2-devel] [PATCH v2 2/4] ocfs2_dlm_seq_next should increase position index Vasily Averin
[Ocfs2-devel] [PATCH v2 3/4] nst_seq_next should increase position index Vasily Averin
[Ocfs2-devel] [PATCH v2 4/4] sc_seq_next should increase position index
I added the log in seq_read, use the 'dd' read command above, print as follows:
2020-03-21T11:27:50.691302+08:00|notice|kernel[-]|[92756.285422] [22000/dd] --> seq_read, init, start ppos 250434, max read size 10, m->read_pos 250434, mem index 1028, mem size 4096, mem from 233, mem count 11.
2020-03-21T11:27:50.691328+08:00|notice|kernel[-]|[92756.285430] [22000/dd] --> seq_read, init, start ppos 250444, max read size 10, m->read_pos 250444, mem index 1028, mem size 4096, mem from 243, mem count 1.
2020-03-21T11:27:50.691355+08:00|notice|kernel[-]|[92756.285442] [22000/dd] --> seq_read, read start, m->read_pos 250444, mem index 1028, mem size 4096, mem from 0, mem count 0.
2020-03-21T11:27:50.691381+08:00|notice|kernel[-]|[92756.285444] [22000/dd] --> seq_read, before go to file, mem file count 244, mem file size 4096
2020-03-21T11:27:50.691406+08:00|notice|kernel[-]|[92756.285453] [22000/dd] --> seq_read, init, start ppos 250454, max read size 10, m->read_pos 250454, mem index 1029, mem size 4096, mem from 9, mem count 235.
2020-03-21T11:27:50.691434+08:00|notice|kernel[-]|[92756.285458] [22000/dd] --> seq_read, init, start ppos 250464, max read size 10, m->read_pos 250464, mem index 1029, mem size 4096, mem from 19, mem count 225.
......
I haven't figured out what the reason is, but the result is not as expected.
On 2020/3/9 16:27, piaojun wrote:
>
>
>
> -------- Forwarded Message --------
> Subject: Re: [PATCH v2 0/4] ocfs2: seq_file .next functions should increase position index
> Date: Wed, 26 Feb 2020 16:32:30 +0800
> From: Joseph Qi <joseph.qi@linux.alibaba.com>
> To: Vasily Averin <vvs@virtuozzo.com>, ocfs2-devel at oss.oracle.com, piaojun <piaojun@huawei.com>
> CC: Mark Fasheh <mark@fasheh.com>, Joel Becker <jlbec@evilplan.org>
>
> Looks good.
> Jun, could you please help verify these changes and give your tested-by? Since I don't have ocfs2 cluster locally...
>
> Thanks,
> Joseph
>
> On 2020/2/26 14:52, Vasily Averin wrote:
>> v2: resend with improved patch description
>>
>> In Aug 2018 NeilBrown noticed
>> commit 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface")
>> "Some ->next functions do not increment *pos when they return NULL...
>> Note that such ->next functions are buggy and should be fixed.
>> A simple demonstration is
>>
>> dd if=/proc/swaps bs=1000 skip=1
>>
>> Choose any block size larger than the size of /proc/swaps. This will
>> always show the whole last line of /proc/swaps"
>>
>> /proc/swaps output was fixed recently, however there are lot of other
>> affected files and 4 of them are related to ocfs2.
>>
>> Unfortunately I'm not familiar with ocfs2 and cannot verify the patches locally.
>>
>> Usually you can observe following related problems:
>> - read after lseek beyond end of file, described above by NeilBrown
>> "dd if=<AFFECTED_FILE> bs=1000 skip=1" will incorrectly generate whole last line
>>
>> - read after lseek on into middle of last line will output expected rest of
>> last line but then repeat whole last line once again.
>>
>> - If .show() function generates multi-line output following bash script will never finish.
>>
>> $ q=;while read -r r;do echo "$((++q)) $r";done < AFFECTED_FILE
>>
>> Link: https://urldefense.com/v3/__https://bugzilla.kernel.org/show_bug.cgi?id=206283__;!!GqivPVa7Brio!KCKPYUMw_U1HxUL22F1ZSc3jh5A-b_7ZVR-iw9uPAprEKFstRKwLXaJmpXuqsTjpGIByXQ$
>>
>> Vasily Averin (4):
>> lockres_seq_next should increase position index
>> ocfs2_dlm_seq_next should increase position index
>> nst_seq_next should increase position index
>> sc_seq_next should increase position index
>>
>> fs/ocfs2/cluster/netdebug.c | 2 ++
>> fs/ocfs2/dlm/dlmdebug.c | 1 +
>> fs/ocfs2/dlmglue.c | 1 +
>> 3 files changed, 4 insertions(+)
>>
> .
>
>
> .
>
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Ocfs2-devel] Fwd: Re: [PATCH v2 0/4] ocfs2: seq_file .next functions should increase position index
2020-03-21 4:24 ` [Ocfs2-devel] Fwd: " lishan
@ 2020-03-22 7:27 ` Vasily Averin
2020-04-14 6:16 ` [Ocfs2-devel] [PATCH v3 0/4] ocfs2: seq_operation should properly handle " Vasily Averin
` (4 more replies)
0 siblings, 5 replies; 15+ messages in thread
From: Vasily Averin @ 2020-03-22 7:27 UTC (permalink / raw)
To: ocfs2-devel
Dear lishan,
thank you for your experiments.
Dear all, please drop my patch-set, they are incomplete.
seq_opetations used in ocfs2 are incorrect -- they ignores position index provided by seq_read().
by design .start() functions should skip first elements specified by *pos argument,
however lockres_seq_start(), ocfs2_dlm_seq_start() and other igores *pos, and uses own logic instead.
It should be reworked.
Thank you,
Vasily Averin
On 3/21/20 7:24 AM, lishan wrote:
> test environment:
> kernel version: 5.6.0-rc5
>
> lockres_seq_next -->
> /sys/kernel/debug/o2dlm/2C9B43EBE44D4715A0B0DBE4D72016A3/locking_state
> The output content is incomplete and endless, and the subsequent output is skip reading.
> The operation and print is as follows:
> dd if=/sys/kernel/debug/o2dlm/2C9B43EBE44D4715A0B0DBE4D72016A3/locking_state bs=40 skip=1
> S:1,5,0,0,0,0,0,0,0,0,3
> RMAP:
> LVBX:00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
> LOCK:1,0,5,-1,5,5:1,0,0,0,0,0,0,0,0,2
>
> NAME:M0000000000000000000042e7349704
> LRES:1,5,0,0,0,0,0,0,0,0,3
> RMAP:
> LVBX:00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
> LOCK:1,0,5,-1,5,5:2,0,0,0,0,0,0,0,0,2
> ........
> NAME:M0000000000000000000042e7349704
> LRES:1,5,0,0,0,0,0,0,0,0,3
> RMAP:
> LVBX:00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
> LOCK:1,0,5,-1,5,5:2,0,0,0,0,0,0,0,0,2
>
> NAME:M0000000000000000000010e7349704
> ......
>
> but, there is no endless output using the following script:
> linux-EalnPD:~ # q=;while read -r r;do echo "$((++q)) $r";done < /sys/kernel/debug/o2dlm/2C9B43EBE44D4715A0B0DBE4D72016A3/locking_state
> 1 NAME:S000000000000000000000200000000
> 2 LRES:1,5,0,0,0,0,0,0,0,0,3
> 3 RMAP:
> 4 LVBX:00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
> 5 LOCK:1,0,5,-1,5,5:6,0,0,0,0,0,0,0,0,2
> 6
> 7
> 8 NAME:M0000000000000000000016e7349704
> 9 NAME:M0000000000000000000018e7349704
> 10 NAME:M000000000000000000001ae7349704
> 11 NAME:M000000000000000000001ce7349704
> 12 NAME:M000000000000000000001ee7349704
> 13 NAME:M0000000000000000000020e7349704
> ....
> 534 NAME:W00000000000000000843c81d0b7768
> 535 NAME:O00000000000000000843c800000000
>
> Other interface test results:
> nst_seq_next --> /sys/kernel/debug/o2net/send_tracking
> sc_seq_next --> /sys/kernel/debug/o2net/stats
> File content is empty, so, read it like use dd command, No effect.
> ocfs2_dlm_seq_next -->
> /sys/kernel/debug/ocfs2/2C9B43EBE44D4715A0B0DBE4D72016A3/locking_state
> Read file normal output.
>
> And, output is still endless, after adding Vasily Averin's modifications, patch are as follow:
> [Ocfs2-devel] [PATCH v2 1/4] lockres_seq_next should increase position index Vasily Averin
> [Ocfs2-devel] [PATCH v2 2/4] ocfs2_dlm_seq_next should increase position index Vasily Averin
> [Ocfs2-devel] [PATCH v2 3/4] nst_seq_next should increase position index Vasily Averin
> [Ocfs2-devel] [PATCH v2 4/4] sc_seq_next should increase position index
>
> I added the log in seq_read, use the 'dd' read command above, print as follows:
> 2020-03-21T11:27:50.691302+08:00|notice|kernel[-]|[92756.285422] [22000/dd] --> seq_read, init, start ppos 250434, max read size 10, m->read_pos 250434, mem index 1028, mem size 4096, mem from 233, mem count 11.
> 2020-03-21T11:27:50.691328+08:00|notice|kernel[-]|[92756.285430] [22000/dd] --> seq_read, init, start ppos 250444, max read size 10, m->read_pos 250444, mem index 1028, mem size 4096, mem from 243, mem count 1.
> 2020-03-21T11:27:50.691355+08:00|notice|kernel[-]|[92756.285442] [22000/dd] --> seq_read, read start, m->read_pos 250444, mem index 1028, mem size 4096, mem from 0, mem count 0.
> 2020-03-21T11:27:50.691381+08:00|notice|kernel[-]|[92756.285444] [22000/dd] --> seq_read, before go to file, mem file count 244, mem file size 4096
> 2020-03-21T11:27:50.691406+08:00|notice|kernel[-]|[92756.285453] [22000/dd] --> seq_read, init, start ppos 250454, max read size 10, m->read_pos 250454, mem index 1029, mem size 4096, mem from 9, mem count 235.
> 2020-03-21T11:27:50.691434+08:00|notice|kernel[-]|[92756.285458] [22000/dd] --> seq_read, init, start ppos 250464, max read size 10, m->read_pos 250464, mem index 1029, mem size 4096, mem from 19, mem count 225.
> ......
>
> I haven't figured out what the reason is, but the result is not as expected.
>
> On 2020/3/9 16:27, piaojun wrote:
>>
>>
>>
>> -------- Forwarded Message --------
>> Subject: Re: [PATCH v2 0/4] ocfs2: seq_file .next functions should increase position index
>> Date: Wed, 26 Feb 2020 16:32:30 +0800
>> From: Joseph Qi <joseph.qi@linux.alibaba.com>
>> To: Vasily Averin <vvs@virtuozzo.com>, ocfs2-devel at oss.oracle.com, piaojun <piaojun@huawei.com>
>> CC: Mark Fasheh <mark@fasheh.com>, Joel Becker <jlbec@evilplan.org>
>>
>> Looks good.
>> Jun, could you please help verify these changes and give your tested-by? Since I don't have ocfs2 cluster locally...
>>
>> Thanks,
>> Joseph
>>
>> On 2020/2/26 14:52, Vasily Averin wrote:
>>> v2: resend with improved patch description
>>>
>>> In Aug 2018 NeilBrown noticed
>>> commit 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface")
>>> "Some ->next functions do not increment *pos when they return NULL...
>>> Note that such ->next functions are buggy and should be fixed.
>>> A simple demonstration is
>>>
>>> dd if=/proc/swaps bs=1000 skip=1
>>>
>>> Choose any block size larger than the size of /proc/swaps. This will
>>> always show the whole last line of /proc/swaps"
>>>
>>> /proc/swaps output was fixed recently, however there are lot of other
>>> affected files and 4 of them are related to ocfs2.
>>>
>>> Unfortunately I'm not familiar with ocfs2 and cannot verify the patches locally.
>>>
>>> Usually you can observe following related problems:
>>> - read after lseek beyond end of file, described above by NeilBrown
>>> "dd if=<AFFECTED_FILE> bs=1000 skip=1" will incorrectly generate whole last line
>>>
>>> - read after lseek on into middle of last line will output expected rest of
>>> last line but then repeat whole last line once again.
>>>
>>> - If .show() function generates multi-line output following bash script will never finish.
>>>
>>> $ q=;while read -r r;do echo "$((++q)) $r";done < AFFECTED_FILE
>>>
>>> Link: https://urldefense.com/v3/__https://bugzilla.kernel.org/show_bug.cgi?id=206283__;!!GqivPVa7Brio!NwJIBH5pk_PU0nl3GdikAyWr88AIZXuC-YDPoiMU1ltEcROIRtcSY_EHVaiSzeRD-Jpafw$
>>>
>>> Vasily Averin (4):
>>> lockres_seq_next should increase position index
>>> ocfs2_dlm_seq_next should increase position index
>>> nst_seq_next should increase position index
>>> sc_seq_next should increase position index
>>>
>>> fs/ocfs2/cluster/netdebug.c | 2 ++
>>> fs/ocfs2/dlm/dlmdebug.c | 1 +
>>> fs/ocfs2/dlmglue.c | 1 +
>>> 3 files changed, 4 insertions(+)
>>>
>> .
>>
>>
>> .
>>
>
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Ocfs2-devel] [PATCH v3 0/4] ocfs2: seq_operation should properly handle position index
2020-03-22 7:27 ` Vasily Averin
@ 2020-04-14 6:16 ` Vasily Averin
2020-04-14 6:17 ` [Ocfs2-devel] [PATCH v3 1/4] ocfs2: debug_lockres_ops " Vasily Averin
` (3 subsequent siblings)
4 siblings, 0 replies; 15+ messages in thread
From: Vasily Averin @ 2020-04-14 6:16 UTC (permalink / raw)
To: ocfs2-devel
v3: rework of ocfs2-related seq_operation functions to properly handle position index argument
v2: resend with improved patch description
In Aug 2018 NeilBrown noticed
commit 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code and interface")
"Some ->next functions do not increment *pos when they return NULL...
Note that such ->next functions are buggy and should be fixed.
A simple demonstration is
dd if=/proc/swaps bs=1000 skip=1
Choose any block size larger than the size of /proc/swaps. This will
always show the whole last line of /proc/swaps"
/proc/swaps output was fixed recently [1], however there are lot of other
affected files and 4 of them are related to ocfs2.
Moreover lishan@ experiments showed that ocfs2-related seq_operations
completely ignores position index argument and it leads to incorrect output. [2]
Usually you can observe following related problems:
- read after lseek beyond end of file, described above by NeilBrown
"dd if=<AFFECTED_FILE> bs=1000 skip=1" will incorrectly generate whole last line
- read after lseek on into middle of last line will output expected rest of
last line but then repeat whole last line once again.
- If .show() function generates multi-line output following bash script will never finish.
$ q=;while read -r r;do echo "$((++q)) $r";done < AFFECTED_FILE
[1] Link: https://urldefense.com/v3/__https://bugzilla.kernel.org/show_bug.cgi?id=206283__;!!GqivPVa7Brio!M3Zvpw7fOUG9cadeYNB9Nc7yQqx_CxPjQKa1xVL-HV09pGqXsi_4x0J6l5LuvKgjTUVSrQ$
[2] Link: https://oss.oracle.com/pipermail/ocfs2-devel/2020-March/014822.html
Vasily Averin (4):
ocfs2: debug_lockres_ops should properly handle position index
ocfs2: ocfs2_dlm_seq_ops should properly handle position index
ocfs2: nst_seq_ops should properly handle position index
ocfs2: sc_seq_ops should properly handle position index
fs/ocfs2/cluster/netdebug.c | 24 +++++++-----
fs/ocfs2/dlm/dlmdebug.c | 78 ++++++++++++++++++-------------------
fs/ocfs2/dlmglue.c | 10 +++--
3 files changed, 59 insertions(+), 53 deletions(-)
--
2.17.1
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Ocfs2-devel] [PATCH v3 1/4] ocfs2: debug_lockres_ops should properly handle position index
2020-03-22 7:27 ` Vasily Averin
2020-04-14 6:16 ` [Ocfs2-devel] [PATCH v3 0/4] ocfs2: seq_operation should properly handle " Vasily Averin
@ 2020-04-14 6:17 ` Vasily Averin
2020-04-14 6:17 ` [Ocfs2-devel] [PATCH v3 2/4] ocfs2: ocfs2_dlm_seq_ops " Vasily Averin
` (2 subsequent siblings)
4 siblings, 0 replies; 15+ messages in thread
From: Vasily Averin @ 2020-04-14 6:17 UTC (permalink / raw)
To: ocfs2-devel
Currently debug_lockres_ops ignores position index argument,
and it leads to incorrect output in case of read with offset.
Link: https://oss.oracle.com/pipermail/ocfs2-devel/2020-March/014822.html
By design .start function should skip first *pos elements,
and .next function must update position index unconditionally.
debug_lockres_ops was reworked to satisfy these requirements:
- .start and .next functions iterates on dlm->tracking_list
by using seq_list_* primitives
- .show generates output related to selected dlm_lock_resource
- .stop function is used to release taken dlm_lock_resource
Cc: stable at vger.kernel.org
Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code ...")
Link: https://urldefense.com/v3/__https://bugzilla.kernel.org/show_bug.cgi?id=206283__;!!GqivPVa7Brio!KOf5kpSuieredwp9lEzV0BQklJAQy4ix8PUtCrqkLdv2TsSnX570XW7JT9gBvV6thJkj2g$
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
---
fs/ocfs2/dlm/dlmdebug.c | 78 ++++++++++++++++++++---------------------
1 file changed, 39 insertions(+), 39 deletions(-)
diff --git a/fs/ocfs2/dlm/dlmdebug.c b/fs/ocfs2/dlm/dlmdebug.c
index 4b8b41d23e91..1887affbbf2c 100644
--- a/fs/ocfs2/dlm/dlmdebug.c
+++ b/fs/ocfs2/dlm/dlmdebug.c
@@ -542,63 +542,63 @@ static void *lockres_seq_start(struct seq_file *m, loff_t *pos)
{
struct debug_lockres *dl = m->private;
struct dlm_ctxt *dlm = dl->dl_ctxt;
- struct dlm_lock_resource *oldres = dl->dl_res;
struct dlm_lock_resource *res = NULL;
- struct list_head *track_list;
+ struct list_head *lh;
spin_lock(&dlm->track_lock);
- if (oldres)
- track_list = &oldres->tracking;
- else {
- track_list = &dlm->tracking_list;
- if (list_empty(track_list)) {
- dl = NULL;
- spin_unlock(&dlm->track_lock);
- goto bail;
- }
- }
-
- list_for_each_entry(res, track_list, tracking) {
- if (&res->tracking == &dlm->tracking_list)
- res = NULL;
- else
- dlm_lockres_get(res);
- break;
+ lh = seq_list_start(&dlm->tracking_list, *pos);
+ if (lh) {
+ res = list_entry(lh, struct dlm_lock_resource, tracking);
+ dlm_lockres_get(res);
}
+ dl->dl_res = res;
spin_unlock(&dlm->track_lock);
+ /* passed to seq_show */
+ return res ? dl : NULL;
+}
- if (oldres)
- dlm_lockres_put(oldres);
+static void *lockres_seq_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ struct debug_lockres *dl = (struct debug_lockres *)v;
+ struct dlm_ctxt *dlm = dl->dl_ctxt;
+ struct dlm_lock_resource *oldres = dl->dl_res;
+ struct dlm_lock_resource *res = NULL;
+ struct list_head *lh;
+ spin_lock(&dlm->track_lock);
+ lh = seq_list_next(&oldres->tracking, &dlm->tracking_list, pos);
+ if (lh) {
+ res = list_entry(lh, struct dlm_lock_resource, tracking);
+ dlm_lockres_get(res);
+ }
dl->dl_res = res;
-
- if (res) {
- spin_lock(&res->spinlock);
- dump_lockres(res, dl->dl_buf, dl->dl_len - 1);
- spin_unlock(&res->spinlock);
- } else
- dl = NULL;
-
-bail:
- /* passed to seq_show */
- return dl;
+ spin_unlock(&dlm->track_lock);
+ dlm_lockres_put(oldres);
+ return res ? dl : NULL;
}
static void lockres_seq_stop(struct seq_file *m, void *v)
{
-}
+ struct debug_lockres *dl = (struct debug_lockres *)v;
+ struct dlm_lock_resource *res = dl->dl_res;
-static void *lockres_seq_next(struct seq_file *m, void *v, loff_t *pos)
-{
- return NULL;
+ if (res) {
+ dlm_lockres_put(res);
+ dl->dl_res = NULL;
+ }
}
-static int lockres_seq_show(struct seq_file *s, void *v)
+static int lockres_seq_show(struct seq_file *m, void *v)
{
struct debug_lockres *dl = (struct debug_lockres *)v;
+ struct dlm_lock_resource *res = dl->dl_res;
- seq_printf(s, "%s", dl->dl_buf);
-
+ if (res) {
+ spin_lock(&res->spinlock);
+ dump_lockres(res, dl->dl_buf, dl->dl_len - 1);
+ spin_unlock(&res->spinlock);
+ seq_printf(m, "%s", dl->dl_buf);
+ }
return 0;
}
--
2.17.1
^ permalink raw reply related [flat|nested] 15+ messages in thread
* [Ocfs2-devel] [PATCH v3 2/4] ocfs2: ocfs2_dlm_seq_ops should properly handle position index
2020-03-22 7:27 ` Vasily Averin
2020-04-14 6:16 ` [Ocfs2-devel] [PATCH v3 0/4] ocfs2: seq_operation should properly handle " Vasily Averin
2020-04-14 6:17 ` [Ocfs2-devel] [PATCH v3 1/4] ocfs2: debug_lockres_ops " Vasily Averin
@ 2020-04-14 6:17 ` Vasily Averin
2020-04-14 6:17 ` [Ocfs2-devel] [PATCH v3 3/4] ocfs2: nst_seq_ops " Vasily Averin
2020-04-14 6:17 ` [Ocfs2-devel] [PATCH v3 4/4] ocfs2: sc_seq_ops " Vasily Averin
4 siblings, 0 replies; 15+ messages in thread
From: Vasily Averin @ 2020-04-14 6:17 UTC (permalink / raw)
To: ocfs2-devel
Currently ocfs2_dlm_seq_ops ignores position index argument,
and it leads to incorrect output in case of read with offset.
By design .start function should skip first *pos elements,
and .next function must update position index unconditionally.
Cc: stable at vger.kernel.org
Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code ...")
Link: https://urldefense.com/v3/__https://bugzilla.kernel.org/show_bug.cgi?id=206283__;!!GqivPVa7Brio!MW4at7q5bwj5ULIntJ6umw403Evx0mZ3_sIwjVdK1ltQi595oNDR7IyKESTtl61485TN7g$
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
---
fs/ocfs2/dlmglue.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index 152a0fc4e905..3f5fe6af9f3a 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -3022,7 +3022,8 @@ struct ocfs2_dlm_seq_priv {
};
static struct ocfs2_lock_res *ocfs2_dlm_next_res(struct ocfs2_lock_res *start,
- struct ocfs2_dlm_seq_priv *priv)
+ struct ocfs2_dlm_seq_priv *priv,
+ loff_t pos)
{
struct ocfs2_lock_res *iter, *ret = NULL;
struct ocfs2_dlm_debug *dlm_debug = priv->p_dlm_debug;
@@ -3038,7 +3039,7 @@ static struct ocfs2_lock_res *ocfs2_dlm_next_res(struct ocfs2_lock_res *start,
/* We track our "dummy" iteration lockres' by a NULL
* l_ops field. */
- if (iter->l_ops != NULL) {
+ if ((iter->l_ops != NULL) && (pos-- == 0)) {
ret = iter;
break;
}
@@ -3053,7 +3054,7 @@ static void *ocfs2_dlm_seq_start(struct seq_file *m, loff_t *pos)
struct ocfs2_lock_res *iter;
spin_lock(&ocfs2_dlm_tracking_lock);
- iter = ocfs2_dlm_next_res(&priv->p_iter_res, priv);
+ iter = ocfs2_dlm_next_res(&priv->p_iter_res, priv, *pos);
if (iter) {
/* Since lockres' have the lifetime of their container
* (which can be inodes, ocfs2_supers, etc) we want to
@@ -3080,8 +3081,9 @@ static void *ocfs2_dlm_seq_next(struct seq_file *m, void *v, loff_t *pos)
struct ocfs2_lock_res *iter = v;
struct ocfs2_lock_res *dummy = &priv->p_iter_res;
+ (*pos)++;
spin_lock(&ocfs2_dlm_tracking_lock);
- iter = ocfs2_dlm_next_res(iter, priv);
+ iter = ocfs2_dlm_next_res(iter, priv, 0);
list_del_init(&dummy->l_debug_list);
if (iter) {
list_add(&dummy->l_debug_list, &iter->l_debug_list);
--
2.17.1
^ permalink raw reply related [flat|nested] 15+ messages in thread
* [Ocfs2-devel] [PATCH v3 3/4] ocfs2: nst_seq_ops should properly handle position index
2020-03-22 7:27 ` Vasily Averin
` (2 preceding siblings ...)
2020-04-14 6:17 ` [Ocfs2-devel] [PATCH v3 2/4] ocfs2: ocfs2_dlm_seq_ops " Vasily Averin
@ 2020-04-14 6:17 ` Vasily Averin
2020-04-14 6:17 ` [Ocfs2-devel] [PATCH v3 4/4] ocfs2: sc_seq_ops " Vasily Averin
4 siblings, 0 replies; 15+ messages in thread
From: Vasily Averin @ 2020-04-14 6:17 UTC (permalink / raw)
To: ocfs2-devel
Currently nst_seq_ops ignores position index argument,
and it leads to incorrect output in case of read with offset.
By design .start function should skip first *pos elements,
and .next function must update position index unconditionally.
Cc: stable at vger.kernel.org
Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code ...")
Link: https://urldefense.com/v3/__https://bugzilla.kernel.org/show_bug.cgi?id=206283__;!!GqivPVa7Brio!McCQFYlmRnNmoAtY2bRAeiRzKSgC0c8B5r-Oy1meJpaRZaM5TbD5lECuzD96ZyERbIiA3Q$
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
---
fs/ocfs2/cluster/netdebug.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/fs/ocfs2/cluster/netdebug.c b/fs/ocfs2/cluster/netdebug.c
index 667a5c5e1f66..8ca8a407781b 100644
--- a/fs/ocfs2/cluster/netdebug.c
+++ b/fs/ocfs2/cluster/netdebug.c
@@ -60,7 +60,8 @@ void o2net_debug_del_nst(struct o2net_send_tracking *nst)
}
static struct o2net_send_tracking
- *next_nst(struct o2net_send_tracking *nst_start)
+ *next_nst(struct o2net_send_tracking *nst_start,
+ loff_t pos)
{
struct o2net_send_tracking *nst, *ret = NULL;
@@ -73,7 +74,7 @@ static struct o2net_send_tracking
break;
/* use st_task to detect real nsts in the list */
- if (nst->st_task != NULL) {
+ if ((nst->st_task != NULL) && (pos-- == 0)) {
ret = nst;
break;
}
@@ -87,7 +88,7 @@ static void *nst_seq_start(struct seq_file *seq, loff_t *pos)
struct o2net_send_tracking *nst, *dummy_nst = seq->private;
spin_lock(&o2net_debug_lock);
- nst = next_nst(dummy_nst);
+ nst = next_nst(dummy_nst, *pos);
spin_unlock(&o2net_debug_lock);
return nst;
@@ -97,8 +98,9 @@ static void *nst_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct o2net_send_tracking *nst, *dummy_nst = seq->private;
+ (*pos)++;
spin_lock(&o2net_debug_lock);
- nst = next_nst(dummy_nst);
+ nst = next_nst(dummy_nst, 0);
list_del_init(&dummy_nst->st_net_debug_item);
if (nst)
list_add(&dummy_nst->st_net_debug_item,
@@ -115,7 +117,7 @@ static int nst_seq_show(struct seq_file *seq, void *v)
s64 sock, send, status;
spin_lock(&o2net_debug_lock);
- nst = next_nst(dummy_nst);
+ nst = next_nst(dummy_nst, 0);
if (!nst)
goto out;
--
2.17.1
^ permalink raw reply related [flat|nested] 15+ messages in thread
* [Ocfs2-devel] [PATCH v3 4/4] ocfs2: sc_seq_ops should properly handle position index
2020-03-22 7:27 ` Vasily Averin
` (3 preceding siblings ...)
2020-04-14 6:17 ` [Ocfs2-devel] [PATCH v3 3/4] ocfs2: nst_seq_ops " Vasily Averin
@ 2020-04-14 6:17 ` Vasily Averin
4 siblings, 0 replies; 15+ messages in thread
From: Vasily Averin @ 2020-04-14 6:17 UTC (permalink / raw)
To: ocfs2-devel
Currently sc_seq_ops ignores position index argument,
and it leads to incorrect output in case of read with offset.
By design .start function should skip first *pos elements,
and .next function must update position index unconditionally.
Cc: stable at vger.kernel.org
Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code ...")
Link: https://urldefense.com/v3/__https://bugzilla.kernel.org/show_bug.cgi?id=206283__;!!GqivPVa7Brio!MJIyl9g4rZXkCRJpUtfNR70zABIYk0zKHrl00gKDdYZpx41lpyanlE7z50esOWCIqgd95w$
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
---
fs/ocfs2/cluster/netdebug.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/fs/ocfs2/cluster/netdebug.c b/fs/ocfs2/cluster/netdebug.c
index 8ca8a407781b..832fd762e4ef 100644
--- a/fs/ocfs2/cluster/netdebug.c
+++ b/fs/ocfs2/cluster/netdebug.c
@@ -213,7 +213,8 @@ struct o2net_sock_debug {
};
static struct o2net_sock_container
- *next_sc(struct o2net_sock_container *sc_start)
+ *next_sc(struct o2net_sock_container *sc_start,
+ loff_t pos)
{
struct o2net_sock_container *sc, *ret = NULL;
@@ -226,7 +227,7 @@ static struct o2net_sock_container
break;
/* use sc_page to detect real scs in the list */
- if (sc->sc_page != NULL) {
+ if ((sc->sc_page != NULL) && (pos-- == 0)) {
ret = sc;
break;
}
@@ -241,7 +242,7 @@ static void *sc_seq_start(struct seq_file *seq, loff_t *pos)
struct o2net_sock_container *sc, *dummy_sc = sd->dbg_sock;
spin_lock(&o2net_debug_lock);
- sc = next_sc(dummy_sc);
+ sc = next_sc(dummy_sc, *pos);
spin_unlock(&o2net_debug_lock);
return sc;
@@ -252,8 +253,9 @@ static void *sc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
struct o2net_sock_debug *sd = seq->private;
struct o2net_sock_container *sc, *dummy_sc = sd->dbg_sock;
+ ++(*pos);
spin_lock(&o2net_debug_lock);
- sc = next_sc(dummy_sc);
+ sc = next_sc(dummy_sc, 0);
list_del_init(&dummy_sc->sc_net_debug_item);
if (sc)
list_add(&dummy_sc->sc_net_debug_item, &sc->sc_net_debug_item);
@@ -354,7 +356,7 @@ static int sc_seq_show(struct seq_file *seq, void *v)
struct o2net_sock_container *sc, *dummy_sc = sd->dbg_sock;
spin_lock(&o2net_debug_lock);
- sc = next_sc(dummy_sc);
+ sc = next_sc(dummy_sc, 0);
if (sc) {
if (sd->dbg_ctxt == SHOW_SOCK_CONTAINERS)
--
2.17.1
^ permalink raw reply related [flat|nested] 15+ messages in thread
end of thread, other threads:[~2020-04-14 6:17 UTC | newest]
Thread overview: 15+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
[not found] <ca1497b7-6a6e-8043-63c7-b17c094ebc05@virtuozzo.com>
2020-01-26 2:21 ` [Ocfs2-devel] [PATCH 1/4] lockres_seq_next should increase position index Joseph Qi
2020-02-26 6:52 ` [Ocfs2-devel] [PATCH v2 0/4] ocfs2: seq_file .next functions " Vasily Averin
2020-02-26 8:32 ` Joseph Qi
2020-03-09 11:32 ` piaojun
[not found] ` <e954f783-5a1c-8847-7b0d-298825ee06a4@huawei.com>
2020-03-21 4:24 ` [Ocfs2-devel] Fwd: " lishan
2020-03-22 7:27 ` Vasily Averin
2020-04-14 6:16 ` [Ocfs2-devel] [PATCH v3 0/4] ocfs2: seq_operation should properly handle " Vasily Averin
2020-04-14 6:17 ` [Ocfs2-devel] [PATCH v3 1/4] ocfs2: debug_lockres_ops " Vasily Averin
2020-04-14 6:17 ` [Ocfs2-devel] [PATCH v3 2/4] ocfs2: ocfs2_dlm_seq_ops " Vasily Averin
2020-04-14 6:17 ` [Ocfs2-devel] [PATCH v3 3/4] ocfs2: nst_seq_ops " Vasily Averin
2020-04-14 6:17 ` [Ocfs2-devel] [PATCH v3 4/4] ocfs2: sc_seq_ops " Vasily Averin
2020-02-26 6:53 ` [Ocfs2-devel] [PATCH v2 1/4] lockres_seq_next should increase " Vasily Averin
2020-02-26 6:53 ` [Ocfs2-devel] [PATCH v2 2/4] ocfs2_dlm_seq_next " Vasily Averin
2020-02-26 6:53 ` [Ocfs2-devel] [PATCH v2 3/4] nst_seq_next " Vasily Averin
2020-02-26 6:54 ` [Ocfs2-devel] [PATCH v2 4/4] sc_seq_next " Vasily Averin
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).