> -----Original Message----- > From: Jaegeuk Kim [mailto:jaegeuk@xxxxxxxxxx] > Sent: Friday, December 25, 2015 4:16 AM > To: Chao Yu > Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-fsdevel@xxxxxxxxxxxxxxx; > linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > Subject: Re: [f2fs-dev] [PATCH 2/4] f2fs: return early when trying to read null nid > > On Thu, Dec 24, 2015 at 01:49:24PM +0800, Chao Yu wrote: > > Hi Jaegeuk, > > > > > -----Original Message----- > > > From: Jaegeuk Kim [mailto:jaegeuk@xxxxxxxxxx] > > > Sent: Thursday, December 24, 2015 10:15 AM > > > To: linux-kernel@xxxxxxxxxxxxxxx; linux-fsdevel@xxxxxxxxxxxxxxx; > > > linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > > > Cc: Jaegeuk Kim > > > Subject: [f2fs-dev] [PATCH 2/4] f2fs: return early when trying to read null nid > > > > > > If get_node_page() gets zero nid, we can return early without getting a wrong > > > page. For example, get_dnode_of_data() can try to do that. > > > > Good catch! > > > > > > > > Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx> > > > --- > > > fs/f2fs/node.c | 3 +++ > > > 1 file changed, 3 insertions(+) > > > > > > diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c > > > index 341de5d..e17128d 100644 > > > --- a/fs/f2fs/node.c > > > +++ b/fs/f2fs/node.c > > > @@ -1059,6 +1059,9 @@ struct page *get_node_page(struct f2fs_sb_info *sbi, pgoff_t nid) > > > { > > > struct page *page; > > > int err; > > > + > > > + if (!nid) > > > + return ERR_PTR(-ENOENT); > > > > How about expand to check upper and lower boundary: > > > > if (check_nid_range) > > return ERR_PTR(-ENOENT); > > It'd better to add f2fs_bug_on(check_nid_range()) after this. > Cause check_nid_range() checks its nid as *unlikely*, but this case seems > *likely*. Agreed. Thanks, > > Thanks, > > > > > Thanks, > > > > > repeat: > > > page = grab_cache_page(NODE_MAPPING(sbi), nid); > > > if (!page) > > > -- > > > 2.5.4 (Apple Git-61) > > > > > > > > > ------------------------------------------------------------------------------ > > > _______________________________________________ > > > Linux-f2fs-devel mailing list > > > Linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > > > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
