2013-03-18 05:54:45

by Jaegeuk Kim

[permalink] [raw]
Subject: [PATCH] f2fs: fix not to allocate max_nid

The build_free_nid should not add free nids over nm_i->max_nid.
But, there was a hole that invalid free nid was added by the following scenario.

Let's suppose nm_i->max_nid = 150 and the last NAT page has 100 ~ 200 nids.

build_free_nids
- get_current_nat_page loads the last NAT page
- scan_nat_page can add 100 ~ 200 nids
-> Bug here!
So, when scanning an NAT page, we should check each candidate whether it is
over max_nid or not.

Signed-off-by: Jaegeuk Kim <[email protected]>
---
fs/f2fs/node.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index c60919f..3fb6dfe 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1270,6 +1270,8 @@ static int scan_nat_page(struct f2fs_nm_info *nm_i,
i = start_nid % NAT_ENTRY_PER_BLOCK;

for (; i < NAT_ENTRY_PER_BLOCK; i++, start_nid++) {
+ if (start_nid >= nm_i->max_nid)
+ return fcnt;
blk_addr = le32_to_cpu(nat_blk->entries[i].block_addr);
BUG_ON(blk_addr == NEW_ADDR);
if (blk_addr == NULL_ADDR)
--
1.8.1.3.566.gaa39828


2013-03-18 09:29:09

by Namjae Jeon

[permalink] [raw]
Subject: Re: [PATCH] f2fs: fix not to allocate max_nid

2013/3/18, Jaegeuk Kim <[email protected]>:
> The build_free_nid should not add free nids over nm_i->max_nid.
> But, there was a hole that invalid free nid was added by the following
> scenario.
>
> Let's suppose nm_i->max_nid = 150 and the last NAT page has 100 ~ 200 nids.
>
> build_free_nids
> - get_current_nat_page loads the last NAT page
> - scan_nat_page can add 100 ~ 200 nids
> -> Bug here!
> So, when scanning an NAT page, we should check each candidate whether it is
> over max_nid or not.
>
> Signed-off-by: Jaegeuk Kim <[email protected]>
> ---
> fs/f2fs/node.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> index c60919f..3fb6dfe 100644
> --- a/fs/f2fs/node.c
> +++ b/fs/f2fs/node.c
> @@ -1270,6 +1270,8 @@ static int scan_nat_page(struct f2fs_nm_info *nm_i,
> i = start_nid % NAT_ENTRY_PER_BLOCK;
>
> for (; i < NAT_ENTRY_PER_BLOCK; i++, start_nid++) {
> + if (start_nid >= nm_i->max_nid)
> + return fcnt;
Hi Jaegeuk.
How about use "break;" instread of "return fcnt" ?
I think that break is better because there is no extra condition before return.

Thanks.
> blk_addr = le32_to_cpu(nat_blk->entries[i].block_addr);
> BUG_ON(blk_addr == NEW_ADDR);
> if (blk_addr == NULL_ADDR)
> --
> 1.8.1.3.566.gaa39828
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>

2013-03-18 10:13:59

by Jaegeuk Kim

[permalink] [raw]
Subject: Re: [PATCH] f2fs: fix not to allocate max_nid

2013-03-18 (월), 18:29 +0900, Namjae Jeon:
> 2013/3/18, Jaegeuk Kim <[email protected]>:
> > The build_free_nid should not add free nids over nm_i->max_nid.
> > But, there was a hole that invalid free nid was added by the following
> > scenario.
> >
> > Let's suppose nm_i->max_nid = 150 and the last NAT page has 100 ~ 200 nids.
> >
> > build_free_nids
> > - get_current_nat_page loads the last NAT page
> > - scan_nat_page can add 100 ~ 200 nids
> > -> Bug here!
> > So, when scanning an NAT page, we should check each candidate whether it is
> > over max_nid or not.
> >
> > Signed-off-by: Jaegeuk Kim <[email protected]>
> > ---
> > fs/f2fs/node.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
> > index c60919f..3fb6dfe 100644
> > --- a/fs/f2fs/node.c
> > +++ b/fs/f2fs/node.c
> > @@ -1270,6 +1270,8 @@ static int scan_nat_page(struct f2fs_nm_info *nm_i,
> > i = start_nid % NAT_ENTRY_PER_BLOCK;
> >
> > for (; i < NAT_ENTRY_PER_BLOCK; i++, start_nid++) {
> > + if (start_nid >= nm_i->max_nid)
> > + return fcnt;
> Hi Jaegeuk.
> How about use "break;" instread of "return fcnt" ?
> I think that break is better because there is no extra condition before return.

Ok, thanks. :)

>
> Thanks.
> > blk_addr = le32_to_cpu(nat_blk->entries[i].block_addr);
> > BUG_ON(blk_addr == NEW_ADDR);
> > if (blk_addr == NULL_ADDR)
> > --
> > 1.8.1.3.566.gaa39828
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
> > the body of a message to [email protected]
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
> >
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/

--
Jaegeuk Kim
Samsung

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2013-03-18 11:28:50

by Namjae Jeon

[permalink] [raw]
Subject: Re: [PATCH] f2fs: fix not to allocate max_nid

2013/3/18, Jaegeuk Kim <[email protected]>:
> 2013-03-18 (월), 18:29 +0900, Namjae Jeon:
>> 2013/3/18, Jaegeuk Kim <[email protected]>:
>> > The build_free_nid should not add free nids over nm_i->max_nid.
>> > But, there was a hole that invalid free nid was added by the following
>> > scenario.
>> >
>> > Let's suppose nm_i->max_nid = 150 and the last NAT page has 100 ~ 200
>> > nids.
>> >
>> > build_free_nids
>> > - get_current_nat_page loads the last NAT page
>> > - scan_nat_page can add 100 ~ 200 nids
>> > -> Bug here!
>> > So, when scanning an NAT page, we should check each candidate whether it
>> > is
>> > over max_nid or not.
>> >
>> > Signed-off-by: Jaegeuk Kim <[email protected]>
>> > ---
>> > fs/f2fs/node.c | 2 ++
>> > 1 file changed, 2 insertions(+)
>> >
>> > diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
>> > index c60919f..3fb6dfe 100644
>> > --- a/fs/f2fs/node.c
>> > +++ b/fs/f2fs/node.c
>> > @@ -1270,6 +1270,8 @@ static int scan_nat_page(struct f2fs_nm_info
>> > *nm_i,
>> > i = start_nid % NAT_ENTRY_PER_BLOCK;
>> >
>> > for (; i < NAT_ENTRY_PER_BLOCK; i++, start_nid++) {
>> > + if (start_nid >= nm_i->max_nid)
>> > + return fcnt;
>> Hi Jaegeuk.
>> How about use "break;" instread of "return fcnt" ?
>> I think that break is better because there is no extra condition before
>> return.
>
> Ok, thanks. :)
Okay, you can add
Reviewed-by: Namjae Jeon <[email protected]>
Thanks.

>
>>
>> Thanks.
>> > blk_addr = le32_to_cpu(nat_blk->entries[i].block_addr);
>> > BUG_ON(blk_addr == NEW_ADDR);
>> > if (blk_addr == NULL_ADDR)
>> > --
>> > 1.8.1.3.566.gaa39828
>> >
>> > --
>> > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel"
>> > in
>> > the body of a message to [email protected]
>> > More majordomo info at http://vger.kernel.org/majordomo-info.html
>> >
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-kernel"
>> in
>> the body of a message to [email protected]
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at http://www.tux.org/lkml/
>
> --
> Jaegeuk Kim
> Samsung
>