Re: [PATCH v2 1/5] fs: Introduce i_blocks_per_page

Darrick J. Wong
2019-09-18T21:30:12Z

On Tue, Aug 20, 2019 at 05:30:35PM -0700, Matthew Wilcox wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
>
> This helper is useful for both large pages in the page cache and for
> supporting block size larger than page size. Convert some example
> users (we have a few different ways of writing this idiom).
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Seems pretty straightforward, modulo whatever's going on with the kbuild
robot complaint (is there something wrong, or is it just that obnoxious
header check thing?)

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
> fs/iomap/buffered-io.c | 4 ++--
> fs/jfs/jfs_metapage.c | 2 +-
> fs/xfs/xfs_aops.c | 8 ++++----
> include/linux/pagemap.h | 13 +++++++++++++
> 4 files changed, 20 insertions(+), 7 deletions(-)
>
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index e25901ae3ff4..0e76a4b6d98a 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -24,7 +24,7 @@ iomap_page_create(struct inode *inode, struct page *page)
> {
> struct iomap_page *iop = to_iomap_page(page);
>
> - if (iop || i_blocksize(inode) == PAGE_SIZE)
> + if (iop || i_blocks_per_page(inode, page) <= 1)
> return iop;
>
> iop = kmalloc(sizeof(*iop), GFP_NOFS | __GFP_NOFAIL);
> @@ -128,7 +128,7 @@ iomap_set_range_uptodate(struct page *page, unsigned off, unsigned len)
> bool uptodate = true;
>
> if (iop) {
> - for (i = 0; i < PAGE_SIZE / i_blocksize(inode); i++) {
> + for (i = 0; i < i_blocks_per_page(inode, page); i++) {
> if (i >= first && i <= last)
> set_bit(i, iop->uptodate);
> else if (!test_bit(i, iop->uptodate))
> diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
> index a2f5338a5ea1..176580f54af9 100644
> --- a/fs/jfs/jfs_metapage.c
> +++ b/fs/jfs/jfs_metapage.c
> @@ -473,7 +473,7 @@ static int metapage_readpage(struct file *fp, struct page *page)
> struct inode *inode = page->mapping->host;
> struct bio *bio = NULL;
> int block_offset;
> - int blocks_per_page = PAGE_SIZE >> inode->i_blkbits;
> + int blocks_per_page = i_blocks_per_page(inode, page);
> sector_t page_start; /* address of page in fs blocks */
> sector_t pblock;
> int xlen;
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index f16d5f196c6b..102cfd8a97d6 100644
> --- a/fs/xfs/xfs_aops.c
> +++ b/fs/xfs/xfs_aops.c
> @@ -68,7 +68,7 @@ xfs_finish_page_writeback(
> mapping_set_error(inode->i_mapping, -EIO);
> }
>
> - ASSERT(iop || i_blocksize(inode) == PAGE_SIZE);
> + ASSERT(iop || i_blocks_per_page(inode, bvec->bv_page) <= 1);
> ASSERT(!iop || atomic_read(&iop->write_count) > 0);
>
> if (!iop || atomic_dec_and_test(&iop->write_count))
> @@ -839,7 +839,7 @@ xfs_aops_discard_page(
> page, ip->i_ino, offset);
>
> error = xfs_bmap_punch_delalloc_range(ip, start_fsb,
> - PAGE_SIZE / i_blocksize(inode));
> + i_blocks_per_page(inode, page));
> if (error && !XFS_FORCED_SHUTDOWN(mp))
> xfs_alert(mp, "page discard unable to remove delalloc mapping.");
> out_invalidate:
> @@ -877,7 +877,7 @@ xfs_writepage_map(
> uint64_t file_offset; /* file offset of page */
> int error = 0, count = 0, i;
>
> - ASSERT(iop || i_blocksize(inode) == PAGE_SIZE);
> + ASSERT(iop || i_blocks_per_page(inode, page) <= 1);
> ASSERT(!iop || atomic_read(&iop->write_count) == 0);
>
> /*
> @@ -886,7 +886,7 @@ xfs_writepage_map(
> * one.
> */
> for (i = 0, file_offset = page_offset(page);
> - i < (PAGE_SIZE >> inode->i_blkbits) && file_offset < end_offset;
> + i < i_blocks_per_page(inode, page) && file_offset < end_offset;
> i++, file_offset += len) {
> if (iop && !test_bit(i, iop->uptodate))
> continue;
> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> index cf837d313b96..2728f20fbc49 100644
> --- a/include/linux/pagemap.h
> +++ b/include/linux/pagemap.h
> @@ -644,4 +644,17 @@ static inline unsigned long dir_pages(struct inode *inode)
> PAGE_SHIFT;
> }
>
> +/**
> + * i_blocks_per_page - How many blocks fit in this page.
> + * @inode: The inode which contains the blocks.
> + * @page: The (potentially large) page.
> + *
> + * Context: Any context.
> + * Return: The number of filesystem blocks covered by this page.
> + */
> +static inline
> +unsigned int i_blocks_per_page(struct inode *inode, struct page *page)
> +{
> + return page_size(page) >> inode->i_blkbits;
> +}
> #endif /* _LINUX_PAGEMAP_H */
> --
> 2.23.0.rc1
>