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Date: Wed, 25 May 2016 09:54:38 -0700 From: Jaegeuk Kim <jaegeuk@...nel.org> To: Yunlong Song <yunlong.song@...wei.com> Cc: cm224.lee@...sung.com, yuchao0@...wei.com, chao@...nel.org, sylinux@....com, bintian.wang@...wei.com, houpengyang@...wei.com, heyunlei@...wei.com, liushuoran@...wei.com, shiguojun@...wei.com, linux-f2fs-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org Subject: Re: [PATCH] f2fs: Return the errno to the caller to avoid using a wrong page Hi Yunlong, Do we have a bug report in terms of this? Thanks, On Wed, May 25, 2016 at 09:01:01PM +0800, Yunlong Song wrote: > Commit aaf9607516ed38825268515ef4d773289a44f429 ("f2fs: check node page > contents all the time") pointed out that "sometimes it was reported that > its contents was missing", so it checks the page's mapping and contents. > When "nid != nid_of_node(page)", ERR_PTR(-EIO) will be returned to the > caller. However, commit e1c51b9f1df2f9efc2ec11488717e40cd12015f9 ("f2fs: > clean up node page updating flow") moves "nid != nid_of_node(page)" test > to "f2fs_bug_on(sbi, nid != nid_of_node(page))", this will return a > wrong page to the caller when F2FS_CHECK_FS is off when "sometimes it > was reported that its contents was missing" happens. > > This patch restores to check node page contents all the time, and > returns the errno to make the caller known something is wrong and avoid > to use the page. This patch also moves f2fs_bug_on to its proper location. > > Signed-off-by: Yunlong Song <yunlong.song@...wei.com> > --- > fs/f2fs/node.c | 12 +++++------- > 1 file changed, 5 insertions(+), 7 deletions(-) > > diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c > index 1f21aae..4b04af4 100644 > --- a/fs/f2fs/node.c > +++ b/fs/f2fs/node.c > @@ -1140,16 +1140,16 @@ repeat: > if (err < 0) { > f2fs_put_page(page, 1); > return ERR_PTR(err); > - } else if (err == LOCKED_PAGE) { > - goto page_hit; > + } else if (err != LOCKED_PAGE) { > + lock_page(page); > } > > if (parent) > ra_node_pages(parent, start + 1, MAX_RA_NODE); > > - lock_page(page); > - > - if (unlikely(!PageUptodate(page))) { > + if (unlikely(!PageUptodate(page) || nid != nid_of_node(page))) { > + f2fs_bug_on(sbi, 1); > + ClearPageUptodate(page); > f2fs_put_page(page, 1); > return ERR_PTR(-EIO); > } > @@ -1157,8 +1157,6 @@ repeat: > f2fs_put_page(page, 1); > goto repeat; > } > -page_hit: > - f2fs_bug_on(sbi, nid != nid_of_node(page)); > return page; > } > > -- > 1.8.5.2
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