From 807c6d09cc99cbdf9933edfadcbaa8f0b856848d Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 5 Jan 2024 22:03:58 +0000 Subject: netfs: Fix the loop that unmarks folios after writing to the cache In the loop in netfs_rreq_unmark_after_write() that removes the PG_fscache from folios after they've been written to the cache, as soon as we remove the mark from a multipage folio, it can get split - and then we might see a fragment of folio again. Guard against this by advancing the 'unlocked' tracker to the index of the last page in the folio to avoid a double removal of the PG_fscache mark. Reported-by: Marc Dionne Signed-off-by: David Howells cc: Matthew Wilcox cc: linux-afs@lists.infradead.org cc: linux-cachefs@redhat.com cc: linux-fsdevel@vger.kernel.org cc: linux-mm@kvack.org --- fs/netfs/buffered_write.c | 1 + fs/netfs/io.c | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/netfs') diff --git a/fs/netfs/buffered_write.c b/fs/netfs/buffered_write.c index 6cd8f7422e9a..0b2b7a60dabc 100644 --- a/fs/netfs/buffered_write.c +++ b/fs/netfs/buffered_write.c @@ -698,6 +698,7 @@ static void netfs_pages_written_back(struct netfs_io_request *wreq) end_wb: if (folio_test_fscache(folio)) folio_end_fscache(folio); + xas_advance(&xas, folio_next_index(folio) - 1); folio_end_writeback(folio); } diff --git a/fs/netfs/io.c b/fs/netfs/io.c index 5b5af96cd4b9..4309edf33862 100644 --- a/fs/netfs/io.c +++ b/fs/netfs/io.c @@ -126,7 +126,7 @@ static void netfs_rreq_unmark_after_write(struct netfs_io_request *rreq, */ if (have_unlocked && folio_index(folio) <= unlocked) continue; - unlocked = folio_index(folio); + unlocked = folio_next_index(folio) - 1; trace_netfs_folio(folio, netfs_folio_trace_end_copy); folio_end_fscache(folio); have_unlocked = true; -- cgit