Again, what about prefixing patches with the subsystems they affect?
This would be mm: or fs:.
On Saturday 04 April 2009 02:55:02 David Howells wrote:
> The attached patch causes read_cache_pages() to release page-private data on a
> page for which add_to_page_cache() fails. If the filler function fails, then
> the problematic page is left attached to the pagecache (with appropriate flags
> set, one presumes) and the remaining to-be-attached pages are invalidated and
> discarded. This permits pages with caching references associated with them to
> be cleaned up.
>
> The invalidatepage() address space op is called (indirectly) to do the honours.
>
> Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
> Acked-by: Steve Dickson <steved@xxxxxxxxxx>
> Acked-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
> Acked-by: Rik van Riel <riel@xxxxxxxxxx>
> Acked-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> Tested-by: Daire Byrne <Daire.Byrne@xxxxxxxxxxxxxx>
> ---
>
> include/linux/page-flags.h | 2 +-
> mm/readahead.c | 39 +++++++++++++++++++++++++++++++++++++--
> 2 files changed, 38 insertions(+), 3 deletions(-)
>
>
> diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
> index 61df177..9d99e74 100644
> --- a/include/linux/page-flags.h
> +++ b/include/linux/page-flags.h
> @@ -182,7 +182,7 @@ static inline int TestClearPage##uname(struct page *page) { return 0; }
>
> struct page; /* forward declaration */
>
> -TESTPAGEFLAG(Locked, locked)
> +TESTPAGEFLAG(Locked, locked) TESTSETFLAG(Locked, locked)
> PAGEFLAG(Error, error)
> PAGEFLAG(Referenced, referenced) TESTCLEARFLAG(Referenced, referenced)
> PAGEFLAG(Dirty, dirty) TESTSCFLAG(Dirty, dirty) __CLEARPAGEFLAG(Dirty, dirty)
> diff --git a/mm/readahead.c b/mm/readahead.c
> index 9ce303d..6be9275 100644
> --- a/mm/readahead.c
> +++ b/mm/readahead.c
> @@ -31,6 +31,41 @@ EXPORT_SYMBOL_GPL(file_ra_state_init);
>
> #define list_to_page(head) (list_entry((head)->prev, struct page, lru))
>
> +/*
> + * see if a page needs releasing upon read_cache_pages() failure
> + * - the caller of read_cache_pages() may have set PG_private before calling,
> + * such as the NFS fs marking pages that are cached locally on disk, thus we
> + * need to give the fs a chance to clean up in the event of an error
> + */
> +static void read_cache_pages_invalidate_page(struct address_space *mapping,
> + struct page *page)
> +{
> + if (PagePrivate(page)) {
> + if (!trylock_page(page))
> + BUG();
> + page->mapping = mapping;
> + do_invalidatepage(page, 0);
> + page->mapping = NULL;
> + unlock_page(page);
> + }
> + page_cache_release(page);
> +}
> +
> +/*
> + * release a list of pages, invalidating them first if need be
> + */
> +static void read_cache_pages_invalidate_pages(struct address_space *mapping,
> + struct list_head *pages)
> +{
> + struct page *victim;
> +
> + while (!list_empty(pages)) {
> + victim = list_to_page(pages);
> + list_del(&victim->lru);
> + read_cache_pages_invalidate_page(mapping, victim);
> + }
> +}
> +
> /**
> * read_cache_pages - populate an address space with some pages & start reads against them
> * @mapping: the address_space
> @@ -52,14 +87,14 @@ int read_cache_pages(struct address_space *mapping, struct list_head *pages,
> list_del(&page->lru);
> if (add_to_page_cache_lru(page, mapping,
> page->index, GFP_KERNEL)) {
> - page_cache_release(page);
> + read_cache_pages_invalidate_page(mapping, page);
> continue;
> }
> page_cache_release(page);
>
> ret = filler(data, page);
> if (unlikely(ret)) {
> - put_pages_list(pages);
> + read_cache_pages_invalidate_pages(mapping, pages);
> break;
> }
> task_io_account_read(PAGE_CACHE_SIZE);
>
> --
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