linux-kernel - RE: [PATCH 1/2] pstore: avoid incorrectly mark entry as duplicate

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Message-ID: <A5ED84D3BB3A384992CBB9C77DEDA4D47F9D388F@USINDEM103.corp.hds.com>
Date:	Wed, 30 Oct 2013 14:35:27 +0000
From:	Seiji Aguchi <seiji.aguchi@....com>
To:	Madper Xie <cxie@...hat.com>,
	"tony.luck@...el.com" <tony.luck@...el.com>,
	"keescook@...omium.org" <keescook@...omium.org>,
	"ccross@...roid.com" <ccross@...roid.com>,
	"anton@...msg.org" <anton@...msg.org>
CC:	"linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"bbboson@...il.com" <bbboson@...il.com>
Subject: RE: [PATCH 1/2] pstore: avoid incorrectly mark entry as duplicate



> -----Original Message-----
> From: Madper Xie [mailto:cxie@...hat.com]
> Sent: Wednesday, October 30, 2013 5:45 AM
> To: tony.luck@...el.com; keescook@...omium.org; ccross@...roid.com; anton@...msg.org; Seiji Aguchi
> Cc: linux-efi@...r.kernel.org; linux-kernel@...r.kernel.org; bbboson@...il.com; Madper Xie
> Subject: [PATCH 1/2] pstore: avoid incorrectly mark entry as duplicate
> 
> From: Madper Xie <bbboson@...il.com>
> 
> 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 two more checks: timespec and count.
> 
> Signed-off-by: Madper Xie <cxie@...hat.com>

Looks good to me.
Acked-by: Seiji Aguchi <seiji.aguchi@....com>

But, this patch has to be tested by other backend drivers like erst and ramoops.
In my understanding, erst has supported to log multiple events.
So, I'm interested why the same error hasn't happened in the other drivers.

Seiji

> ---
>  fs/pstore/inode.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
> index 1282384..0ae994c 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 +291,9 @@ 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 &&
> +		    pos->count == count &&
> +		    !timespec_compare(&pos->time, &time)) {
>  			rc = -EEXIST;
>  			break;
>  		}
> @@ -312,6 +315,7 @@ 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:
> --
> 1.8.4.2

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