From: Matthew Wilcox (Oracle) willy@infradead.org
[ Upstream commit fb5c2029f8221e904e604938171c4a8ef169aadb ]
If the last folio in a file is split as a result of truncation, we simply clear the dirty bits for the pages we're discarding. That causes NR_FILE_DIRTY (among other counters) to be thrown off and eventually Linux will hang in balance_dirty_pages_ratelimited()
Reported-by: Dave Chinner dchinner@redhat.com Tested-by: Dave Chinner dchinner@redhat.com Tested-by: Darrick J. Wong djwong@kernel.org Fixes: d68eccad3706 ("mm/filemap: Allow large folios to be added to the page cache") Signed-off-by: Matthew Wilcox (Oracle) willy@infradead.org Signed-off-by: Sasha Levin sashal@kernel.org --- mm/huge_memory.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 834f288b3769..15965084816d 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -18,6 +18,7 @@ #include <linux/shrinker.h> #include <linux/mm_inline.h> #include <linux/swapops.h> +#include <linux/backing-dev.h> #include <linux/dax.h> #include <linux/khugepaged.h> #include <linux/freezer.h> @@ -2440,11 +2441,15 @@ static void __split_huge_page(struct page *page, struct list_head *list, __split_huge_page_tail(head, i, lruvec, list); /* Some pages can be beyond EOF: drop them from page cache */ if (head[i].index >= end) { - ClearPageDirty(head + i); - __delete_from_page_cache(head + i, NULL); + struct folio *tail = page_folio(head + i); + if (shmem_mapping(head->mapping)) shmem_uncharge(head->mapping->host, 1); - put_page(head + i); + else if (folio_test_clear_dirty(tail)) + folio_account_cleaned(tail, + inode_to_wb(folio->mapping->host)); + __filemap_remove_folio(tail, NULL); + folio_put(tail); } else if (!PageAnon(page)) { __xa_store(&head->mapping->i_pages, head[i].index, head + i, 0);