There is some ambiguity around the use of PagePrivate. It's generally expected in core code that if PagePrivate is set then you have a reference to it. It's not clear that ceph always does (and I believe it may not). Change ceph to use attach/detach_page_private so that we keep a reference to the page until the snap context is detached. Lore: https://lore.kernel.org/ceph-devel/2503810.1616508988@xxxxxxxxxxxxxxxxxxxxxx/T/#u Reported-by: David Howells <dhowells@xxxxxxxxxx> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> --- fs/ceph/addr.c | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-) diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c index b476133353ae..db1f5667fc42 100644 --- a/fs/ceph/addr.c +++ b/fs/ceph/addr.c @@ -128,8 +128,7 @@ static int ceph_set_page_dirty(struct page *page) * PagePrivate so that we get invalidatepage callback. */ BUG_ON(PagePrivate(page)); - page->private = (unsigned long)snapc; - SetPagePrivate(page); + attach_page_private(page, snapc); ret = __set_page_dirty_nobuffers(page); WARN_ON(!PageLocked(page)); @@ -148,7 +147,7 @@ static void ceph_invalidatepage(struct page *page, unsigned int offset, { struct inode *inode; struct ceph_inode_info *ci; - struct ceph_snap_context *snapc = page_snap_context(page); + struct ceph_snap_context *snapc; wait_on_page_fscache(page); @@ -168,10 +167,9 @@ static void ceph_invalidatepage(struct page *page, unsigned int offset, dout("%p invalidatepage %p idx %lu full dirty page\n", inode, page, page->index); + snapc = detach_page_private(page); ceph_put_wrbuffer_cap_refs(ci, 1, snapc); ceph_put_snap_context(snapc); - page->private = 0; - ClearPagePrivate(page); } static int ceph_releasepage(struct page *page, gfp_t gfp) @@ -588,8 +586,8 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc) dout("writepage cleaned page %p\n", page); err = 0; /* vfs expects us to return 0 */ } - page->private = 0; - ClearPagePrivate(page); + oldest = detach_page_private(page); + WARN_ON_ONCE(oldest != snapc); end_page_writeback(page); ceph_put_wrbuffer_cap_refs(ci, 1, snapc); ceph_put_snap_context(snapc); /* page's reference */ @@ -681,11 +679,9 @@ static void writepages_finish(struct ceph_osd_request *req) clear_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC); - ceph_put_snap_context(page_snap_context(page)); - page->private = 0; - ClearPagePrivate(page); - dout("unlocking %p\n", page); + ceph_put_snap_context(detach_page_private(page)); end_page_writeback(page); + dout("unlocking %p\n", page); if (remove_page) generic_error_remove_page(inode->i_mapping, -- 2.30.2
