From 5d899d43ed293b854fa4f6adc3138fd6fa12aecf Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 15 Feb 2024 07:36:40 +0100 Subject: writeback: only update ->writeback_index for range_cyclic writeback mapping->writeback_index is only [1] used as the starting point for range_cyclic writeback, so there is no point in updating it for other types of writeback. [1] except for btrfs_defrag_file which does really odd things with mapping->writeback_index. But btrfs doesn't use write_cache_pages at all, so this isn't relevant here. Link: https://lkml.kernel.org/r/20240215063649.2164017-6-hch@lst.de Signed-off-by: Christoph Hellwig Reviewed-by: Brian Foster Reviewed-by: Jan Kara Acked-by: Dave Chinner Cc: Christian Brauner Cc: David Howells Cc: "Matthew Wilcox (Oracle)" Signed-off-by: Andrew Morton --- mm/page-writeback.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-) (limited to 'mm/page-writeback.c') diff --git a/mm/page-writeback.c b/mm/page-writeback.c index abbee369405a..f02014007b57 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -2403,7 +2403,6 @@ int write_cache_pages(struct address_space *mapping, pgoff_t index; pgoff_t end; /* Inclusive */ pgoff_t done_index; - int range_whole = 0; xa_mark_t tag; folio_batch_init(&fbatch); @@ -2413,8 +2412,6 @@ int write_cache_pages(struct address_space *mapping, } else { index = wbc->range_start >> PAGE_SHIFT; end = wbc->range_end >> PAGE_SHIFT; - if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) - range_whole = 1; } if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages) { tag_pages_for_writeback(mapping, index, end); @@ -2518,14 +2515,21 @@ continue_unlock: } /* - * If we hit the last page and there is more work to be done: wrap - * back the index back to the start of the file for the next - * time we are called. + * For range cyclic writeback we need to remember where we stopped so + * that we can continue there next time we are called. If we hit the + * last page and there is more work to be done, wrap back to the start + * of the file. + * + * For non-cyclic writeback we always start looking up at the beginning + * of the file if we are called again, which can only happen due to + * -ENOMEM from the file system. */ - if (wbc->range_cyclic && !done) - done_index = 0; - if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) - mapping->writeback_index = done_index; + if (wbc->range_cyclic) { + if (done) + mapping->writeback_index = done_index; + else + mapping->writeback_index = 0; + } return ret; } -- cgit v1.2.3