Messages in this thread | | | Date | Mon, 27 Mar 2023 08:30:33 -0700 | From | Jaegeuk Kim <> | Subject | Re: [f2fs-dev] [PATCH] f2fs: get out of a repeat loop when getting a locked data page |
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On 03/26, Chao Yu wrote: > On 2023/3/24 5:39, Jaegeuk Kim wrote: > > https://bugzilla.kernel.org/show_bug.cgi?id=216050 > > > > Somehow we're getting a page which has a different mapping. > > Let's avoid the infinite loop. > > > > Cc: <stable@vger.kernel.org> > > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> > > --- > > fs/f2fs/data.c | 8 ++------ > > 1 file changed, 2 insertions(+), 6 deletions(-) > > > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > > index bf51e6e4eb64..80702c93e885 100644 > > --- a/fs/f2fs/data.c > > +++ b/fs/f2fs/data.c > > @@ -1329,18 +1329,14 @@ struct page *f2fs_get_lock_data_page(struct inode *inode, pgoff_t index, > > { > > struct address_space *mapping = inode->i_mapping; > > struct page *page; > > -repeat: > > + > > page = f2fs_get_read_data_page(inode, index, 0, for_write, NULL); > > if (IS_ERR(page)) > > return page; > > /* wait for read completion */ > > lock_page(page); > > - if (unlikely(page->mapping != mapping)) { > > How about using such logic only for move_data_page() to limit affect for > other paths?
Why move_data_page() only? If this happens, we'll fall into a loop in anywhere?
> > Jaegeuk, any thoughts about why mapping is mismatch in between page's one and > inode->i_mapping?
> > After several times code review, I didn't get any clue about why f2fs always > get the different mapping in a loop.
I couldn't find the path to happen this. So weird. Please check the history in the bug.
> > Maybe we can loop MM guys to check whether below folio_file_page() may return > page which has different mapping?
Matthew may have some idea on this?
> > struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index, > int fgp_flags, gfp_t gfp) > { > struct folio *folio; > > folio = __filemap_get_folio(mapping, index, fgp_flags, gfp); > if (IS_ERR(folio)) > return NULL; > return folio_file_page(folio, index); > } > > Thanks, > > > - f2fs_put_page(page, 1); > > - goto repeat; > > - } > > - if (unlikely(!PageUptodate(page))) { > > + if (unlikely(page->mapping != mapping || !PageUptodate(page))) { > > f2fs_put_page(page, 1); > > return ERR_PTR(-EIO); > > }
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