On 2023/3/27 23:30, Jaegeuk Kim wrote:
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@xxxxxxxxxxxxxxx>
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
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?
Actually, we only suffer dead loop from foreground GC path, right? I suspect the
bug was triggered in this path only.
It looks there are a lot of cases in where we repeat triggering read once
two mappings are mismatched, e.g.
- __get_meta_page
- __get_node_page
- f2fs_write_begin
- f2fs_quota_read
Thanks,
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);
}
