2013-10-23 14:55:59

by Madper Xie

[permalink] [raw]
Subject: [PATCH] pstore: avoid incorrectly mark entry as duplicate

pstore try to find duplicate entries by check both ID, type and psi.
They are not really enough for efi backend. dumped vars always have
the same type, psi and ID. like follows:
dump-type0-9-1-1382511508-C-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0
dump-type0-9-1-1382515661-C-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0

The "duplicate" entries won't appear in pstorefs. And a complain will be
print -- pstore: failed to load 76 record(s) from 'efi'
So I add one more check: timespec.

Signed-off-by: Madper Xie <[email protected]>
---
fs/pstore/inode.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index 1282384..f70f1e5 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -47,6 +47,7 @@ static LIST_HEAD(allpstore);
struct pstore_private {
struct list_head list;
struct pstore_info *psi;
+ struct timespec time;
enum pstore_type_id type;
u64 id;
int count;
@@ -290,7 +291,8 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
list_for_each_entry(pos, &allpstore, list) {
if (pos->type == type &&
pos->id == id &&
- pos->psi == psi) {
+ pos->psi == psi &&
+ !timespec_compare(&pos->time, &time)) {
rc = -EEXIST;
break;
}
@@ -312,6 +314,7 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
private->id = id;
private->count = count;
private->psi = psi;
+ memcpy(&private->time, &time, sizeof(struct timespec));

switch (type) {
case PSTORE_TYPE_DMESG:
--
1.8.4.1


2013-10-23 15:58:36

by Richard Weinberger

[permalink] [raw]
Subject: Re: [PATCH] pstore: avoid incorrectly mark entry as duplicate

On Wed, Oct 23, 2013 at 4:55 PM, Madper Xie <[email protected]> wrote:
> pstore try to find duplicate entries by check both ID, type and psi.
> They are not really enough for efi backend. dumped vars always have
> the same type, psi and ID. like follows:
> dump-type0-9-1-1382511508-C-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0
> dump-type0-9-1-1382515661-C-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0
>
> The "duplicate" entries won't appear in pstorefs. And a complain will be
> print -- pstore: failed to load 76 record(s) from 'efi'
> So I add one more check: timespec.
>
> Signed-off-by: Madper Xie <[email protected]>
> ---
> fs/pstore/inode.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
> index 1282384..f70f1e5 100644
> --- a/fs/pstore/inode.c
> +++ b/fs/pstore/inode.c
> @@ -47,6 +47,7 @@ static LIST_HEAD(allpstore);
> struct pstore_private {
> struct list_head list;
> struct pstore_info *psi;
> + struct timespec time;
> enum pstore_type_id type;
> u64 id;
> int count;
> @@ -290,7 +291,8 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
> list_for_each_entry(pos, &allpstore, list) {
> if (pos->type == type &&
> pos->id == id &&
> - pos->psi == psi) {
> + pos->psi == psi &&
> + !timespec_compare(&pos->time, &time)) {
> rc = -EEXIST;
> break;
> }
> @@ -312,6 +314,7 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
> private->id = id;
> private->count = count;
> private->psi = psi;
> + memcpy(&private->time, &time, sizeof(struct timespec));
>
> switch (type) {
> case PSTORE_TYPE_DMESG:


As discussed on IRC, why don't you compare the variable names?

--
Thanks,
//richard

2013-10-23 16:12:08

by Madper Xie

[permalink] [raw]
Subject: Re: [PATCH] pstore: avoid incorrectly mark entry as duplicate


[email protected] writes:

> On Wed, Oct 23, 2013 at 4:55 PM, Madper Xie <[email protected]> wrote:
>> pstore try to find duplicate entries by check both ID, type and psi.
>> They are not really enough for efi backend. dumped vars always have
>> the same type, psi and ID. like follows:
>> dump-type0-9-1-1382511508-C-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0
>> dump-type0-9-1-1382515661-C-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0
>>
>> The "duplicate" entries won't appear in pstorefs. And a complain will be
>> print -- pstore: failed to load 76 record(s) from 'efi'
>> So I add one more check: timespec.
>>
>> Signed-off-by: Madper Xie <[email protected]>
>> ---
>> fs/pstore/inode.c | 5 ++++-
>> 1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
>> index 1282384..f70f1e5 100644
>> --- a/fs/pstore/inode.c
>> +++ b/fs/pstore/inode.c
>> @@ -47,6 +47,7 @@ static LIST_HEAD(allpstore);
>> struct pstore_private {
>> struct list_head list;
>> struct pstore_info *psi;
>> + struct timespec time;
>> enum pstore_type_id type;
>> u64 id;
>> int count;
>> @@ -290,7 +291,8 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
>> list_for_each_entry(pos, &allpstore, list) {
>> if (pos->type == type &&
>> pos->id == id &&
>> - pos->psi == psi) {
>> + pos->psi == psi &&
>> + !timespec_compare(&pos->time, &time)) {
>> rc = -EEXIST;
>> break;
>> }
>> @@ -312,6 +314,7 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
>> private->id = id;
>> private->count = count;
>> private->psi = psi;
>> + memcpy(&private->time, &time, sizeof(struct timespec));
>>
>> switch (type) {
>> case PSTORE_TYPE_DMESG:
>
>
> As discussed on IRC, why don't you compare the variable names?
Howdy Richard,
Let's analyze the name of "duplicate" entries:
>> dump-type0-9-1-1382511508-C-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0
>> dump-type0-9-1-1382515661-C-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0
The have the same name except timestamp. In this case, there is no
difference between compare names and compare timestamps.
( Yeah, I'm pretty sure the guid will be the same one --
LINUX_EFI_CRASH_GUID )
But efi is only one backend. For other backends, we don't sure if they
will add timestamp to name. So...

--
Best,
Madper Xie.

2013-10-23 21:57:08

by Tony Luck

[permalink] [raw]
Subject: Re: [PATCH] pstore: avoid incorrectly mark entry as duplicate

On Wed, Oct 23, 2013 at 7:55 AM, Madper Xie <[email protected]> wrote:
> The "duplicate" entries won't appear in pstorefs. And a complain will be
> print -- pstore: failed to load 76 record(s) from 'efi'

Maybe I don't quite get this - but it sounds like you have a whole lot
of entries using up space in efivars that have similar names - differing
just in the timestamp - that won't show up in the pstore filesystem - because
we'd try to name them all the same thing.

How did all those things end up in efivars?

Wouldn't the right fix be to make pstore allow them all to appear (using the
timestamp to differentiate names?) so that we could see them, log them,
and then remove them from pstore (in turn freeing up efivars space - which
people keep telling me is in short supply).

-Tony

2013-10-24 00:21:53

by Madper Xie

[permalink] [raw]
Subject: Re: [PATCH] pstore: avoid incorrectly mark entry as duplicate


[email protected] writes:

> On Wed, Oct 23, 2013 at 7:55 AM, Madper Xie <[email protected]> wrote:
>> The "duplicate" entries won't appear in pstorefs. And a complain will be
>> print -- pstore: failed to load 76 record(s) from 'efi'
>
> Maybe I don't quite get this - but it sounds like you have a whole lot
> of entries using up space in efivars that have similar names - differing
> just in the timestamp - that won't show up in the pstore filesystem - because
> we'd try to name them all the same thing.
>
Maybe I misunderstand you...

Sure pstore try to name them all the same thing, but it's another
issue. and it doesn't prevent entries showing up in pstore fs.

Consider the following case: (after efi-pstore support append mode, it
always like this case):

I choose four dumped efivars from my DELL XPS:
dump-type0-9-1-1380441690-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0
dump-type0-9-1-1380448560-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0
dump-type0-9-1-1380460890-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0
dump-type0-9-1-1382496073-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0
^ ^ [ ^ ]
! ! !
type timestamp GUID

When pstore load them from efivars, pstore incorrectly assuming that
efivars with the same TYPE, ID and GUID are duplicate.

list_for_each_entry(pos, &allpstore, list) {
if (pos->type == type && /---
pos->id == id && <-| as I said, it only check type,id,psi
pos->psi == psi) { \---
rc = -EEXIST; <- then set -EEXIST, and ignore *dup* entry
break;
}
}
You can see the code above, for those four entries, only one could be
showed in pstorefs, all others will get a -EEXIST. So I add a timestamp
check here, it's the only different part.

> How did all those things end up in efivars?
before the patch I can see
dmesg-efi-1 dmesg-efi-11 dmesg-efi-3 dmesg-efi-5 dmesg-efi-7 dmesg-efi-9
dmesg-efi-10 dmesg-efi-2 dmesg-efi-4 dmesg-efi-6 dmesg-efi-8
after apply the patch:
[root@dhcp-13-41 vars]# ls /dev/pstore/
dmesg-efi-1 dmesg-efi-1 dmesg-efi-11 dmesg-efi-2 dmesg-efi-3 dmesg-efi-5 dmesg-efi-6 dmesg-efi-8
dmesg-efi-1 dmesg-efi-10 dmesg-efi-11 dmesg-efi-2 dmesg-efi-3 dmesg-efi-5 dmesg-efi-7 dmesg-efi-8
dmesg-efi-1 dmesg-efi-10 dmesg-efi-12 dmesg-efi-2 dmesg-efi-4 dmesg-efi-5 dmesg-efi-7 dmesg-efi-8
dmesg-efi-1 dmesg-efi-10 dmesg-efi-13 dmesg-efi-2 dmesg-efi-4 dmesg-efi-5 dmesg-efi-7 dmesg-efi-9
dmesg-efi-1 dmesg-efi-10 dmesg-efi-14 dmesg-efi-2 dmesg-efi-4 dmesg-efi-5 dmesg-efi-7 dmesg-efi-9
dmesg-efi-1 dmesg-efi-10 dmesg-efi-15 dmesg-efi-2 dmesg-efi-4 dmesg-efi-5 dmesg-efi-7 dmesg-efi-9
dmesg-efi-1 dmesg-efi-10 dmesg-efi-16 dmesg-efi-3 dmesg-efi-4 dmesg-efi-5 dmesg-efi-7 dmesg-efi-9
dmesg-efi-1 dmesg-efi-10 dmesg-efi-2 dmesg-efi-3 dmesg-efi-4 dmesg-efi-6 dmesg-efi-7 dmesg-efi-9
dmesg-efi-1 dmesg-efi-10 dmesg-efi-2 dmesg-efi-3 dmesg-efi-4 dmesg-efi-6 dmesg-efi-7 dmesg-efi-9
dmesg-efi-1 dmesg-efi-10 dmesg-efi-2 dmesg-efi-3 dmesg-efi-4 dmesg-efi-6 dmesg-efi-8 dmesg-efi-9
dmesg-efi-1 dmesg-efi-11 dmesg-efi-2 dmesg-efi-3 dmesg-efi-4 dmesg-efi-6 dmesg-efi-8 dmesg-efi-9
dmesg-efi-1 dmesg-efi-11 dmesg-efi-2 dmesg-efi-3 dmesg-efi-4 dmesg-efi-6 dmesg-efi-8 dmesg-efi-9
dmesg-efi-1 dmesg-efi-11 dmesg-efi-2 dmesg-efi-3 dmesg-efi-5 dmesg-efi-6 dmesg-efi-8
dmesg-efi-1 dmesg-efi-11 dmesg-efi-2 dmesg-efi-3 dmesg-efi-5 dmesg-efi-6 dmesg-efi-8
dmesg-efi-1 dmesg-efi-11 dmesg-efi-2 dmesg-efi-3 dmesg-efi-5 dmesg-efi-6 dmesg-efi-8

>
> Wouldn't the right fix be to make pstore allow them all to appear (using the
> timestamp to differentiate names?) so that we could see them, log them,
> and then remove them from pstore (in turn freeing up efivars space - which
> people keep telling me is in short supply).
>
Yeah, many file have the same name, just like my case above. But it not
really block the file shows up and should be solved in another
patch. And I'm trying fix it.
> -Tony

--
Best,
Madper Xie.

2013-10-28 13:37:18

by Madper Xie

[permalink] [raw]
Subject: Re: [PATCH] pstore: avoid incorrectly mark entry as duplicate

Howdy Tony,
Does this patch still need some rework?

[email protected] writes:

> [email protected] writes:
>
>> On Wed, Oct 23, 2013 at 7:55 AM, Madper Xie <[email protected]> wrote:
>>> The "duplicate" entries won't appear in pstorefs. And a complain will be
>>> print -- pstore: failed to load 76 record(s) from 'efi'
>>
>> Maybe I don't quite get this - but it sounds like you have a whole lot
>> of entries using up space in efivars that have similar names - differing
>> just in the timestamp - that won't show up in the pstore filesystem - because
>> we'd try to name them all the same thing.
>>
> Maybe I misunderstand you...
>
> Sure pstore try to name them all the same thing, but it's another
> issue. and it doesn't prevent entries showing up in pstore fs.
>
> Consider the following case: (after efi-pstore support append mode, it
> always like this case):
>
> I choose four dumped efivars from my DELL XPS:
> dump-type0-9-1-1380441690-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0
> dump-type0-9-1-1380448560-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0
> dump-type0-9-1-1380460890-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0
> dump-type0-9-1-1382496073-cfc8fc79-be2e-4ddc-97f0-9f98bfe298a0
> ^ ^ [ ^ ]
> ! ! !
> type timestamp GUID
>
> When pstore load them from efivars, pstore incorrectly assuming that
> efivars with the same TYPE, ID and GUID are duplicate.
>
> list_for_each_entry(pos, &allpstore, list) {
> if (pos->type == type && /---
> pos->id == id && <-| as I said, it only check type,id,psi
> pos->psi == psi) { \---
> rc = -EEXIST; <- then set -EEXIST, and ignore *dup* entry
> break;
> }
> }
> You can see the code above, for those four entries, only one could be
> showed in pstorefs, all others will get a -EEXIST. So I add a timestamp
> check here, it's the only different part.
>
>> How did all those things end up in efivars?
> before the patch I can see
> dmesg-efi-1 dmesg-efi-11 dmesg-efi-3 dmesg-efi-5 dmesg-efi-7 dmesg-efi-9
> dmesg-efi-10 dmesg-efi-2 dmesg-efi-4 dmesg-efi-6 dmesg-efi-8
> after apply the patch:
> [root@dhcp-13-41 vars]# ls /dev/pstore/
> dmesg-efi-1 dmesg-efi-1 dmesg-efi-11 dmesg-efi-2 dmesg-efi-3 dmesg-efi-5 dmesg-efi-6 dmesg-efi-8
> dmesg-efi-1 dmesg-efi-10 dmesg-efi-11 dmesg-efi-2 dmesg-efi-3 dmesg-efi-5 dmesg-efi-7 dmesg-efi-8
> dmesg-efi-1 dmesg-efi-10 dmesg-efi-12 dmesg-efi-2 dmesg-efi-4 dmesg-efi-5 dmesg-efi-7 dmesg-efi-8
> dmesg-efi-1 dmesg-efi-10 dmesg-efi-13 dmesg-efi-2 dmesg-efi-4 dmesg-efi-5 dmesg-efi-7 dmesg-efi-9
> dmesg-efi-1 dmesg-efi-10 dmesg-efi-14 dmesg-efi-2 dmesg-efi-4 dmesg-efi-5 dmesg-efi-7 dmesg-efi-9
> dmesg-efi-1 dmesg-efi-10 dmesg-efi-15 dmesg-efi-2 dmesg-efi-4 dmesg-efi-5 dmesg-efi-7 dmesg-efi-9
> dmesg-efi-1 dmesg-efi-10 dmesg-efi-16 dmesg-efi-3 dmesg-efi-4 dmesg-efi-5 dmesg-efi-7 dmesg-efi-9
> dmesg-efi-1 dmesg-efi-10 dmesg-efi-2 dmesg-efi-3 dmesg-efi-4 dmesg-efi-6 dmesg-efi-7 dmesg-efi-9
> dmesg-efi-1 dmesg-efi-10 dmesg-efi-2 dmesg-efi-3 dmesg-efi-4 dmesg-efi-6 dmesg-efi-7 dmesg-efi-9
> dmesg-efi-1 dmesg-efi-10 dmesg-efi-2 dmesg-efi-3 dmesg-efi-4 dmesg-efi-6 dmesg-efi-8 dmesg-efi-9
> dmesg-efi-1 dmesg-efi-11 dmesg-efi-2 dmesg-efi-3 dmesg-efi-4 dmesg-efi-6 dmesg-efi-8 dmesg-efi-9
> dmesg-efi-1 dmesg-efi-11 dmesg-efi-2 dmesg-efi-3 dmesg-efi-4 dmesg-efi-6 dmesg-efi-8 dmesg-efi-9
> dmesg-efi-1 dmesg-efi-11 dmesg-efi-2 dmesg-efi-3 dmesg-efi-5 dmesg-efi-6 dmesg-efi-8
> dmesg-efi-1 dmesg-efi-11 dmesg-efi-2 dmesg-efi-3 dmesg-efi-5 dmesg-efi-6 dmesg-efi-8
> dmesg-efi-1 dmesg-efi-11 dmesg-efi-2 dmesg-efi-3 dmesg-efi-5 dmesg-efi-6 dmesg-efi-8
>
>>
>> Wouldn't the right fix be to make pstore allow them all to appear (using the
>> timestamp to differentiate names?) so that we could see them, log them,
>> and then remove them from pstore (in turn freeing up efivars space - which
>> people keep telling me is in short supply).
>>
> Yeah, many file have the same name, just like my case above. But it not
> really block the file shows up and should be solved in another
> patch. And I'm trying fix it.
>> -Tony


--
Best,
Madper Xie.