From c25aee9c630fb86f98d79eccb75765067079b972 Mon Sep 17 00:00:00 2001 From: Matthew Brown Date: Wed, 12 Aug 2026 18:13:21 +0100 Subject: [PATCH] ceph: fix leaked inode reference on writeback abort at umount ceph_dirty_folio() takes a wrbuffer claim on each newly dirtied folio: it bumps i_wrbuffer_ref (taking an ihold() on the 0->1 transition) and attaches the snap_context to folio->private. That claim is released only by ceph_put_wrbuffer_cap_refs(), which for a submitted write runs from writepages_finish(). In ceph_submit_write(), if ceph_inc_osd_stopping_blocker() fails -- which happens during umount -- the request is aborted before submission: the already-collected folios are only redirtied and unlocked, so writepages_finish() never runs and the claim is leaked. redirty_page_for_writepage() -> folio_redirty_for_writepage() -> filemap_dirty_folio() sets PG_dirty directly and does not go through ->dirty_folio, so ceph_dirty_folio() is not re-entered to rebalance it. Because every subsequent writeback also fails the osd_stopping_blocker, i_wrbuffer_ref never returns to 0, the ihold() is never dropped, and the inode cannot be evicted: VFS: Busy inodes after unmount of ceph kernel BUG at fs/super.c:650! Release the orphaned claim in the abort path before redirtying, via ceph_undo_wrbuffer_claim(): detach the snap_context, drop the wrbuffer reference (letting i_wrbuffer_ref reach 0 and iput() the inode), and drop the snap_context reference -- i.e. do what writepages_finish() would have done for these never-submitted folios. Only the locked_pages entries are undone; folios still in the fbatch were never dirty-cleared by this call (folio_clear_dirty_for_io() is the ownership-transfer point, and a successful move NULLs the fbatch slot), so they hold no claim this call owns. Cc: stable@vger.kernel.org Fixes: fd7449d937e7 ("ceph: fix generic/421 test failure") Signed-off-by: Matthew Brown Reviewed-by: Xiubo Li Signed-off-by: Ilya Dryomov --- fs/ceph/addr.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c index 7e454b854a0b..657c2cb0f881 100644 --- a/fs/ceph/addr.c +++ b/fs/ceph/addr.c @@ -1429,6 +1429,16 @@ void ceph_shift_unused_folios_left(struct folio_batch *fbatch) fbatch->nr = n; } +static void ceph_undo_wrbuffer_claim(struct inode *inode, struct folio *folio) +{ + struct ceph_snap_context *snapc = folio_detach_private(folio); + + if (!snapc) + return; + ceph_put_wrbuffer_cap_refs(ceph_inode(inode), 1, snapc); + ceph_put_snap_context(snapc); +} + static int ceph_submit_write(struct address_space *mapping, struct writeback_control *wbc, @@ -1492,6 +1502,7 @@ int ceph_submit_write(struct address_space *mapping, if (!page) continue; + ceph_undo_wrbuffer_claim(inode, page_folio(page)); redirty_page_for_writepage(wbc, page); unlock_page(page); }