On Thu 01-11-12 00:58:21, Darrick J. Wong wrote:
> Create a helper function to check if a backing device requires stable page
> writes and, if so, performs the necessary wait. Then, make it so that all
> points in the memory manager that handle making pages writable use the helper
> function. This should provide stable page write support to most filesystems,
> while eliminating unnecessary waiting for devices that don't require the
> feature.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> fs/buffer.c | 2 +-
> fs/ext4/inode.c | 2 +-
> include/linux/pagemap.h | 1 +
> mm/filemap.c | 3 ++-
> mm/page-writeback.c | 11 +++++++++++
> 5 files changed, 16 insertions(+), 3 deletions(-)
>
..
> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> index 830893b..916dae1 100644
> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -2275,3 +2275,14 @@ int mapping_tagged(struct address_space *mapping, int tag)
> return radix_tree_tagged(&mapping->page_tree, tag);
> }
> EXPORT_SYMBOL(mapping_tagged);
> +
> +void wait_on_stable_page_write(struct page *page)
> +{
> + struct backing_dev_info *bdi = page->mapping->backing_dev_info;
> +
> + if (!bdi_cap_stable_pages_required(bdi))
> + return;
> +
> + wait_on_page_writeback(page);
> +}
> +EXPORT_SYMBOL_GPL(wait_on_stable_page_write);
Just one nit: Maybe "wait_if_stable_write()" would describe the function
better? Otherwise the patch looks OK.
Honza
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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