Messages in this thread | | | Subject | Re: [PATCH 2/2] Updating ctime and mtime at syncing | From | Peter Zijlstra <> | Date | Tue, 15 Jan 2008 17:35:11 +0100 |
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On Tue, 2008-01-15 at 19:02 +0300, Anton Salikhmetov wrote:
> diff --git a/mm/page-writeback.c b/mm/page-writeback.c > index 3d3848f..53d0e34 100644 > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -997,35 +997,39 @@ int __set_page_dirty_no_writeback(struct page *page) > */ > int __set_page_dirty_nobuffers(struct page *page) > { > - if (!TestSetPageDirty(page)) { > - struct address_space *mapping = page_mapping(page); > - struct address_space *mapping2; > + struct address_space *mapping = page_mapping(page); > + struct address_space *mapping2; > > - if (!mapping) > - return 1; > + if (!mapping) > + return 1; > > - write_lock_irq(&mapping->tree_lock); > - mapping2 = page_mapping(page); > - if (mapping2) { /* Race with truncate? */ > - BUG_ON(mapping2 != mapping); > - WARN_ON_ONCE(!PagePrivate(page) && !PageUptodate(page)); > - if (mapping_cap_account_dirty(mapping)) { > - __inc_zone_page_state(page, NR_FILE_DIRTY); > - __inc_bdi_stat(mapping->backing_dev_info, > - BDI_RECLAIMABLE); > - task_io_account_write(PAGE_CACHE_SIZE); > - } > - radix_tree_tag_set(&mapping->page_tree, > - page_index(page), PAGECACHE_TAG_DIRTY); > - } > - write_unlock_irq(&mapping->tree_lock); > - if (mapping->host) { > - /* !PageAnon && !swapper_space */ > - __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); > + mapping->mtime = CURRENT_TIME; > + set_bit(AS_MCTIME, &mapping->flags);
This seems vulnerable to the race we have against truncate, handled by the mapping2 magic below. Do we care?
> + > + if (TestSetPageDirty(page)) > + return 0; > + > + write_lock_irq(&mapping->tree_lock); > + mapping2 = page_mapping(page); > + if (mapping2) { > + /* Race with truncate? */ > + BUG_ON(mapping2 != mapping); > + WARN_ON_ONCE(!PagePrivate(page) && !PageUptodate(page)); > + if (mapping_cap_account_dirty(mapping)) { > + __inc_zone_page_state(page, NR_FILE_DIRTY); > + __inc_bdi_stat(mapping->backing_dev_info, > + BDI_RECLAIMABLE); > + task_io_account_write(PAGE_CACHE_SIZE); > } > - return 1; > + radix_tree_tag_set(&mapping->page_tree, > + page_index(page), PAGECACHE_TAG_DIRTY); > } > - return 0; > + write_unlock_irq(&mapping->tree_lock); > + > + if (mapping->host) > + __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); > + > + return 1; > } > EXPORT_SYMBOL(__set_page_dirty_nobuffers); >
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