On 2025/3/3 02:13, Fedor Pchelkin wrote:
On Mon, 03. Mar 01:41, Gao Xiang wrote:
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index 94e9e0bf3bbd..ac01c0ede7f7 100644
I'm looking at the diff of upstream commit and the first thing it does
is to remove zeroing out the folio/page private field here:
// upstream commit 9e2f9d34dd12 ("erofs: handle overlapped pclusters out of crafted images properly")
@@ -1450,7 +1451,6 @@ static void z_erofs_fill_bio_vec(struct bio_vec *bvec,
* file-backed folios will be used instead.
*/
if (folio->private == (void *)Z_EROFS_PREALLOCATED_PAGE) {
- folio->private = 0;
tocache = true;
goto out_tocache;
}
while in 6.1.129 the corresponding fragment seems untouched with the
backport patch. Is it intended?
Yes, because it was added in
commit 2080ca1ed3e4 ("erofs: tidy up `struct z_erofs_bvec`")
and dropped again.
But for Linux 6.6.y and 6.1.y, we don't need to backport
2080ca1ed3e4.
Thanks for overall clarification, Gao!
My concern was that in 6.1 and 6.6 there is still a pattern at that
place, not directly related to 2080ca1ed3e4 ("erofs: tidy up
`struct z_erofs_bvec`"):
1. checking ->private against Z_EROFS_PREALLOCATED_PAGE
2. zeroing out ->private if the previous check holds true
// 6.1/6.6 fragment
if (page->private == Z_EROFS_PREALLOCATED_PAGE) {
WRITE_ONCE(pcl->compressed_bvecs[nr].page, page);
set_page_private(page, 0);
tocache = true;
goto out_tocache;
}
while the upstream patch changed the situation. If it's okay then no
remarks from me. Sorry for the noise..
Yeah, yet as I mentioned `set_page_private(page, 0);`
seems redundant from the codebase, I'm fine with either
way.
Thanks,
Gao Xiang
