Re: [PATCH] f2fs: fix not to allocate max_nid

From: Namjae Jeon
Date: Mon Mar 18 2013 - 07:28:52 EST


2013/3/18, Jaegeuk Kim <jaegeuk.kim@xxxxxxxxxxx>:
> 2013-03-18 (ì), 18:29 +0900, Namjae Jeon:
>> 2013/3/18, Jaegeuk Kim <jaegeuk.kim@xxxxxxxxxxx>:
>> > 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 <jaegeuk.kim@xxxxxxxxxxx>
>> > ---
>> > 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 <namjae.jeon@xxxxxxxxxxx>
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
>> >
>> > --
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>
> --
> Jaegeuk Kim
> Samsung
>
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