[PATCH v2 0/5] iomap & xfs support for large pages

[PATCH v2 0/5] iomap & xfs support for large pages

[Matthew Wilcox]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

In order to support large pages in the page cache, filesystems have
to understand that they're being passed a large page and read or write
the entire large page, rather than just the first page.  This pair of
patches adds that support to XFS.

Still untested beyond compilation.

v2:
 - Added a few helpers per Dave Chinner's suggestions
 - Use GFP_ZERO instead of individually zeroing each field of iop
 - Rewrite iomap_set_range_uptodate() to use bitmap functions instead
   of individual bit operations
 - Drop support for large pages being used for files with inline data
   (it didn't work anyway, because kmap_atomic() is only going to map
   the first page of a compound page)
 - Pass a struct page to xfs_finish_page_writeback instead of the bvec

Matthew Wilcox (Oracle) (5):
  fs: Introduce i_blocks_per_page
  mm: Add file_offset_of_ helpers
  iomap: Support large pages
  xfs: Support large pages
  xfs: Pass a page to xfs_finish_page_writeback

 fs/iomap/buffered-io.c  | 121 ++++++++++++++++++++++++++--------------
 fs/jfs/jfs_metapage.c   |   2 +-
 fs/xfs/xfs_aops.c       |  37 ++++++------
 include/linux/iomap.h   |   2 +-
 include/linux/mm.h      |   2 +
 include/linux/pagemap.h |  38 ++++++++++++-
 6 files changed, 135 insertions(+), 67 deletions(-)

-- 
2.23.0.rc1

[PATCH v2 1/5] fs: Introduce i_blocks_per_page

[Matthew Wilcox]

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>
---
 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

[PATCH v2 2/5] mm: Add file_offset_of_ helpers

[Matthew Wilcox]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

The page_offset function is badly named for people reading the functions
which call it.  The natural meaning of a function with this name would
be 'offset within a page', not 'page offset in bytes within a file'.
Dave Chinner suggests file_offset_of_page() as a replacement function
name and I'm also adding file_offset_of_next_page() as a helper for the
large page work.  Also add kernel-doc for these functions so they show
up in the kernel API book.

page_offset() is retained as a compatibility define for now.
---
 include/linux/pagemap.h | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 2728f20fbc49..84f341109710 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -436,14 +436,33 @@ static inline pgoff_t page_to_pgoff(struct page *page)
 	return page_to_index(page);
 }
 
-/*
- * Return byte-offset into filesystem object for page.
+/**
+ * file_offset_of_page - File offset of this page.
+ * @page: Page cache page.
+ *
+ * Context: Any context.
+ * Return: The offset of the first byte of this page.
  */
-static inline loff_t page_offset(struct page *page)
+static inline loff_t file_offset_of_page(struct page *page)
 {
 	return ((loff_t)page->index) << PAGE_SHIFT;
 }
 
+/* Legacy; please convert callers */
+#define page_offset(page)	file_offset_of_page(page)
+
+/**
+ * file_offset_of_next_page - File offset of the next page.
+ * @page: Page cache page.
+ *
+ * Context: Any context.
+ * Return: The offset of the first byte after this page.
+ */
+static inline loff_t file_offset_of_next_page(struct page *page)
+{
+	return ((loff_t)page->index + compound_nr(page)) << PAGE_SHIFT;
+}
+
 static inline loff_t page_file_offset(struct page *page)
 {
 	return ((loff_t)page_index(page)) << PAGE_SHIFT;
-- 
2.23.0.rc1

[PATCH v2 3/5] iomap: Support large pages

[Matthew Wilcox]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

Change iomap_page from a statically sized uptodate bitmap to a dynamically
allocated uptodate bitmap, allowing an arbitrarily large page.

The only remaining places where iomap assumes an order-0 page are for
files with inline data, where there's no sense in allocating a larger
page.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/iomap/buffered-io.c | 119 ++++++++++++++++++++++++++---------------
 include/linux/iomap.h  |   2 +-
 include/linux/mm.h     |   2 +
 3 files changed, 80 insertions(+), 43 deletions(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 0e76a4b6d98a..15d844a88439 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -23,14 +23,14 @@ static struct iomap_page *
 iomap_page_create(struct inode *inode, struct page *page)
 {
 	struct iomap_page *iop = to_iomap_page(page);
+	unsigned int n;
 
 	if (iop || i_blocks_per_page(inode, page) <= 1)
 		return iop;
 
-	iop = kmalloc(sizeof(*iop), GFP_NOFS | __GFP_NOFAIL);
-	atomic_set(&iop->read_count, 0);
-	atomic_set(&iop->write_count, 0);
-	bitmap_zero(iop->uptodate, PAGE_SIZE / SECTOR_SIZE);
+	n = BITS_TO_LONGS(i_blocks_per_page(inode, page));
+	iop = kmalloc(struct_size(iop, uptodate, n),
+			GFP_NOFS | __GFP_NOFAIL | __GFP_ZERO);
 
 	/*
 	 * migrate_page_move_mapping() assumes that pages with private data have
@@ -61,15 +61,16 @@ iomap_page_release(struct page *page)
  * Calculate the range inside the page that we actually need to read.
  */
 static void
-iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop,
+iomap_adjust_read_range(struct inode *inode, struct page *page,
 		loff_t *pos, loff_t length, unsigned *offp, unsigned *lenp)
 {
+	struct iomap_page *iop = to_iomap_page(page);
 	loff_t orig_pos = *pos;
 	loff_t isize = i_size_read(inode);
 	unsigned block_bits = inode->i_blkbits;
 	unsigned block_size = (1 << block_bits);
-	unsigned poff = offset_in_page(*pos);
-	unsigned plen = min_t(loff_t, PAGE_SIZE - poff, length);
+	unsigned poff = offset_in_this_page(page, *pos);
+	unsigned plen = min_t(loff_t, page_size(page) - poff, length);
 	unsigned first = poff >> block_bits;
 	unsigned last = (poff + plen - 1) >> block_bits;
 
@@ -107,7 +108,8 @@ iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop,
 	 * page cache for blocks that are entirely outside of i_size.
 	 */
 	if (orig_pos <= isize && orig_pos + length > isize) {
-		unsigned end = offset_in_page(isize - 1) >> block_bits;
+		unsigned end = offset_in_this_page(page, isize - 1) >>
+				block_bits;
 
 		if (first <= end && last > end)
 			plen -= (last - end) * block_size;
@@ -121,19 +123,16 @@ static void
 iomap_set_range_uptodate(struct page *page, unsigned off, unsigned len)
 {
 	struct iomap_page *iop = to_iomap_page(page);
-	struct inode *inode = page->mapping->host;
-	unsigned first = off >> inode->i_blkbits;
-	unsigned last = (off + len - 1) >> inode->i_blkbits;
-	unsigned int i;
 	bool uptodate = true;
 
 	if (iop) {
-		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))
-				uptodate = false;
-		}
+		struct inode *inode = page->mapping->host;
+		unsigned first = off >> inode->i_blkbits;
+		unsigned count = len >> inode->i_blkbits;
+
+		bitmap_set(iop->uptodate, first, count);
+		if (!bitmap_full(iop->uptodate, i_blocks_per_page(inode, page)))
+			uptodate = false;
 	}
 
 	if (uptodate && !PageError(page))
@@ -194,6 +193,7 @@ iomap_read_inline_data(struct inode *inode, struct page *page,
 		return;
 
 	BUG_ON(page->index);
+	BUG_ON(PageCompound(page));
 	BUG_ON(size > PAGE_SIZE - offset_in_page(iomap->inline_data));
 
 	addr = kmap_atomic(page);
@@ -203,6 +203,16 @@ iomap_read_inline_data(struct inode *inode, struct page *page,
 	SetPageUptodate(page);
 }
 
+/*
+ * Estimate the number of vectors we need based on the current page size;
+ * if we're wrong we'll end up doing an overly large allocation or needing
+ * to do a second allocation, neither of which is a big deal.
+ */
+static unsigned int iomap_nr_vecs(struct page *page, loff_t length)
+{
+	return (length + page_size(page) - 1) >> page_shift(page);
+}
+
 static loff_t
 iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 		struct iomap *iomap)
@@ -222,7 +232,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 	}
 
 	/* zero post-eof blocks as the page may be mapped */
-	iomap_adjust_read_range(inode, iop, &pos, length, &poff, &plen);
+	iomap_adjust_read_range(inode, page, &pos, length, &poff, &plen);
 	if (plen == 0)
 		goto done;
 
@@ -258,7 +268,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 
 	if (!ctx->bio || !is_contig || bio_full(ctx->bio, plen)) {
 		gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL);
-		int nr_vecs = (length + PAGE_SIZE - 1) >> PAGE_SHIFT;
+		int nr_vecs = iomap_nr_vecs(page, length);
 
 		if (ctx->bio)
 			submit_bio(ctx->bio);
@@ -293,9 +303,9 @@ iomap_readpage(struct page *page, const struct iomap_ops *ops)
 	unsigned poff;
 	loff_t ret;
 
-	for (poff = 0; poff < PAGE_SIZE; poff += ret) {
-		ret = iomap_apply(inode, page_offset(page) + poff,
-				PAGE_SIZE - poff, 0, ops, &ctx,
+	for (poff = 0; poff < page_size(page); poff += ret) {
+		ret = iomap_apply(inode, file_offset_of_page(page) + poff,
+				page_size(page) - poff, 0, ops, &ctx,
 				iomap_readpage_actor);
 		if (ret <= 0) {
 			WARN_ON_ONCE(ret == 0);
@@ -328,7 +338,7 @@ iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos,
 	while (!list_empty(pages)) {
 		struct page *page = lru_to_page(pages);
 
-		if (page_offset(page) >= (u64)pos + length)
+		if (file_offset_of_page(page) >= (u64)pos + length)
 			break;
 
 		list_del(&page->lru);
@@ -342,7 +352,7 @@ iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos,
 		 * readpages call itself as every page gets checked again once
 		 * actually needed.
 		 */
-		*done += PAGE_SIZE;
+		*done += page_size(page);
 		put_page(page);
 	}
 
@@ -355,9 +365,14 @@ iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length,
 {
 	struct iomap_readpage_ctx *ctx = data;
 	loff_t done, ret;
+	size_t left = 0;
+
+	if (ctx->cur_page)
+		left = page_size(ctx->cur_page) -
+					offset_in_this_page(ctx->cur_page, pos);
 
 	for (done = 0; done < length; done += ret) {
-		if (ctx->cur_page && offset_in_page(pos + done) == 0) {
+		if (ctx->cur_page && left == 0) {
 			if (!ctx->cur_page_in_bio)
 				unlock_page(ctx->cur_page);
 			put_page(ctx->cur_page);
@@ -369,14 +384,27 @@ iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length,
 			if (!ctx->cur_page)
 				break;
 			ctx->cur_page_in_bio = false;
+			left = page_size(ctx->cur_page);
 		}
 		ret = iomap_readpage_actor(inode, pos + done, length - done,
 				ctx, iomap);
+		left -= ret;
 	}
 
 	return done;
 }
 
+/* move to fs.h? */
+static inline struct page *readahead_first_page(struct list_head *head)
+{
+	return list_entry(head->prev, struct page, lru);
+}
+
+static inline struct page *readahead_last_page(struct list_head *head)
+{
+	return list_entry(head->next, struct page, lru);
+}
+
 int
 iomap_readpages(struct address_space *mapping, struct list_head *pages,
 		unsigned nr_pages, const struct iomap_ops *ops)
@@ -385,9 +413,10 @@ iomap_readpages(struct address_space *mapping, struct list_head *pages,
 		.pages		= pages,
 		.is_readahead	= true,
 	};
-	loff_t pos = page_offset(list_entry(pages->prev, struct page, lru));
-	loff_t last = page_offset(list_entry(pages->next, struct page, lru));
-	loff_t length = last - pos + PAGE_SIZE, ret = 0;
+	loff_t pos = file_offset_of_page(readahead_first_page(pages));
+	loff_t end = file_offset_of_next_page(readahead_last_page(pages));
+	loff_t length = end - pos;
+	loff_t ret = 0;
 
 	while (length > 0) {
 		ret = iomap_apply(mapping->host, pos, length, 0, ops,
@@ -410,7 +439,7 @@ iomap_readpages(struct address_space *mapping, struct list_head *pages,
 	}
 
 	/*
-	 * Check that we didn't lose a page due to the arcance calling
+	 * Check that we didn't lose a page due to the arcane calling
 	 * conventions..
 	 */
 	WARN_ON_ONCE(!ret && !list_empty(ctx.pages));
@@ -435,7 +464,7 @@ iomap_is_partially_uptodate(struct page *page, unsigned long from,
 	unsigned i;
 
 	/* Limit range to one page */
-	len = min_t(unsigned, PAGE_SIZE - from, count);
+	len = min_t(unsigned, page_size(page) - from, count);
 
 	/* First and last blocks in range within page */
 	first = from >> inode->i_blkbits;
@@ -474,7 +503,7 @@ iomap_invalidatepage(struct page *page, unsigned int offset, unsigned int len)
 	 * If we are invalidating the entire page, clear the dirty state from it
 	 * and release it to avoid unnecessary buildup of the LRU.
 	 */
-	if (offset == 0 && len == PAGE_SIZE) {
+	if (offset == 0 && len == page_size(page)) {
 		WARN_ON_ONCE(PageWriteback(page));
 		cancel_dirty_page(page);
 		iomap_page_release(page);
@@ -550,18 +579,20 @@ static int
 __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len,
 		struct page *page, struct iomap *iomap)
 {
-	struct iomap_page *iop = iomap_page_create(inode, page);
 	loff_t block_size = i_blocksize(inode);
 	loff_t block_start = pos & ~(block_size - 1);
 	loff_t block_end = (pos + len + block_size - 1) & ~(block_size - 1);
-	unsigned from = offset_in_page(pos), to = from + len, poff, plen;
+	unsigned from = offset_in_this_page(page, pos);
+	unsigned to = from + len;
+	unsigned poff, plen;
 	int status = 0;
 
 	if (PageUptodate(page))
 		return 0;
+	iomap_page_create(inode, page);
 
 	do {
-		iomap_adjust_read_range(inode, iop, &block_start,
+		iomap_adjust_read_range(inode, page, &block_start,
 				block_end - block_start, &poff, &plen);
 		if (plen == 0)
 			break;
@@ -673,7 +704,7 @@ __iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
 	 */
 	if (unlikely(copied < len && !PageUptodate(page)))
 		return 0;
-	iomap_set_range_uptodate(page, offset_in_page(pos), len);
+	iomap_set_range_uptodate(page, offset_in_this_page(page, pos), len);
 	iomap_set_page_dirty(page);
 	return copied;
 }
@@ -685,6 +716,7 @@ iomap_write_end_inline(struct inode *inode, struct page *page,
 	void *addr;
 
 	WARN_ON_ONCE(!PageUptodate(page));
+	BUG_ON(PageCompound(page));
 	BUG_ON(pos + copied > PAGE_SIZE - offset_in_page(iomap->inline_data));
 
 	addr = kmap_atomic(page);
@@ -749,6 +781,10 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 		unsigned long bytes;	/* Bytes to write to page */
 		size_t copied;		/* Bytes copied from user */
 
+		/*
+		 * XXX: We don't know what size page we'll find in the
+		 * page cache, so only copy up to a regular page boundary.
+		 */
 		offset = offset_in_page(pos);
 		bytes = min_t(unsigned long, PAGE_SIZE - offset,
 						iov_iter_count(i));
@@ -1041,19 +1077,18 @@ vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops)
 	lock_page(page);
 	size = i_size_read(inode);
 	if ((page->mapping != inode->i_mapping) ||
-	    (page_offset(page) > size)) {
+	    (file_offset_of_page(page) > size)) {
 		/* We overload EFAULT to mean page got truncated */
 		ret = -EFAULT;
 		goto out_unlock;
 	}
 
-	/* page is wholly or partially inside EOF */
-	if (((page->index + 1) << PAGE_SHIFT) > size)
-		length = offset_in_page(size);
+	offset = file_offset_of_page(page);
+	if (size - offset < page_size(page))
+		length = offset_in_this_page(page, size);
 	else
-		length = PAGE_SIZE;
+		length = page_size(page);
 
-	offset = page_offset(page);
 	while (length > 0) {
 		ret = iomap_apply(inode, offset, length,
 				IOMAP_WRITE | IOMAP_FAULT, ops, page,
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index bc499ceae392..86be24a8259b 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -139,7 +139,7 @@ loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length,
 struct iomap_page {
 	atomic_t		read_count;
 	atomic_t		write_count;
-	DECLARE_BITMAP(uptodate, PAGE_SIZE / 512);
+	unsigned long		uptodate[];
 };
 
 static inline struct iomap_page *to_iomap_page(struct page *page)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 726d7f046b49..6892cd712428 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1414,6 +1414,8 @@ static inline void clear_page_pfmemalloc(struct page *page)
 extern void pagefault_out_of_memory(void);
 
 #define offset_in_page(p)	((unsigned long)(p) & ~PAGE_MASK)
+#define offset_in_this_page(page, p)	\
+	((unsigned long)(p) & (page_size(page) - 1))
 
 /*
  * Flags passed to show_mem() and show_free_areas() to suppress output in
-- 
2.23.0.rc1

[PATCH v2 4/5] xfs: Support large pages

[Matthew Wilcox]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

Mostly this is just checking the page size of each page instead of
assuming PAGE_SIZE.  Clean up the logic in writepage a little.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/xfs/xfs_aops.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 102cfd8a97d6..1a26e9ca626b 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -765,7 +765,7 @@ xfs_add_to_ioend(
 	struct xfs_mount	*mp = ip->i_mount;
 	struct block_device	*bdev = xfs_find_bdev_for_inode(inode);
 	unsigned		len = i_blocksize(inode);
-	unsigned		poff = offset & (PAGE_SIZE - 1);
+	unsigned		poff = offset & (page_size(page) - 1);
 	bool			merged, same_page = false;
 	sector_t		sector;
 
@@ -843,7 +843,7 @@ xfs_aops_discard_page(
 	if (error && !XFS_FORCED_SHUTDOWN(mp))
 		xfs_alert(mp, "page discard unable to remove delalloc mapping.");
 out_invalidate:
-	xfs_vm_invalidatepage(page, 0, PAGE_SIZE);
+	xfs_vm_invalidatepage(page, 0, page_size(page));
 }
 
 /*
@@ -984,8 +984,7 @@ xfs_do_writepage(
 	struct xfs_writepage_ctx *wpc = data;
 	struct inode		*inode = page->mapping->host;
 	loff_t			offset;
-	uint64_t              end_offset;
-	pgoff_t                 end_index;
+	uint64_t		end_offset;
 
 	trace_xfs_writepage(inode, page, 0, 0);
 
@@ -1024,10 +1023,9 @@ xfs_do_writepage(
 	 * ---------------------------------^------------------|
 	 */
 	offset = i_size_read(inode);
-	end_index = offset >> PAGE_SHIFT;
-	if (page->index < end_index)
-		end_offset = (xfs_off_t)(page->index + 1) << PAGE_SHIFT;
-	else {
+	end_offset = file_offset_of_next_page(page);
+
+	if (end_offset > offset) {
 		/*
 		 * Check whether the page to write out is beyond or straddles
 		 * i_size or not.
@@ -1039,7 +1037,8 @@ xfs_do_writepage(
 		 * |				    |      Straddles     |
 		 * ---------------------------------^-----------|--------|
 		 */
-		unsigned offset_into_page = offset & (PAGE_SIZE - 1);
+		unsigned offset_into_page = offset_in_this_page(page, offset);
+		pgoff_t end_index = offset >> PAGE_SHIFT;
 
 		/*
 		 * Skip the page if it is fully outside i_size, e.g. due to a
@@ -1070,7 +1069,7 @@ xfs_do_writepage(
 		 * memory is zeroed when mapped, and writes to that region are
 		 * not written out to the file."
 		 */
-		zero_user_segment(page, offset_into_page, PAGE_SIZE);
+		zero_user_segment(page, offset_into_page, page_size(page));
 
 		/* Adjust the end_offset to the end of file */
 		end_offset = offset;
-- 
2.23.0.rc1

[PATCH v2 5/5] xfs: Pass a page to xfs_finish_page_writeback

[Matthew Wilcox]

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

The only part of the bvec we were accessing was the bv_page, so just
pass that instead of the whole bvec.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 fs/xfs/xfs_aops.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 1a26e9ca626b..edcb4797fcc2 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -58,21 +58,21 @@ xfs_find_daxdev_for_inode(
 static void
 xfs_finish_page_writeback(
 	struct inode		*inode,
-	struct bio_vec	*bvec,
+	struct page		*page,
 	int			error)
 {
-	struct iomap_page	*iop = to_iomap_page(bvec->bv_page);
+	struct iomap_page	*iop = to_iomap_page(page);
 
 	if (error) {
-		SetPageError(bvec->bv_page);
+		SetPageError(page);
 		mapping_set_error(inode->i_mapping, -EIO);
 	}
 
-	ASSERT(iop || i_blocks_per_page(inode, bvec->bv_page) <= 1);
+	ASSERT(iop || i_blocks_per_page(inode, page) <= 1);
 	ASSERT(!iop || atomic_read(&iop->write_count) > 0);
 
 	if (!iop || atomic_dec_and_test(&iop->write_count))
-		end_page_writeback(bvec->bv_page);
+		end_page_writeback(page);
 }
 
 /*
@@ -106,7 +106,7 @@ xfs_destroy_ioend(
 
 		/* walk each page on bio, ending page IO on them */
 		bio_for_each_segment_all(bvec, bio, iter_all)
-			xfs_finish_page_writeback(inode, bvec, error);
+			xfs_finish_page_writeback(inode, bvec->bv_page, error);
 		bio_put(bio);
 	}
 
-- 
2.23.0.rc1

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

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 5975 bytes --]

Hi Matthew,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[cannot apply to v5.3-rc5 next-20190823]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Matthew-Wilcox/iomap-xfs-support-for-large-pages/20190823-191138
config: c6x-allyesconfig (attached as .config)
compiler: c6x-elf-gcc (GCC) 7.4.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.4.0 make.cross ARCH=c6x 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from include/linux/blkdev.h:16:0,
                    from include/linux/blk-cgroup.h:21,
                    from include/linux/writeback.h:14,
                    from include/linux/memcontrol.h:22,
                    from include/net/sock.h:53,
                    from net//tipc/socket.h:38,
                    from net//tipc/core.c:44:
   include/linux/pagemap.h: In function 'i_blocks_per_page':
>> include/linux/pagemap.h:640:9: error: implicit declaration of function 'page_size'; did you mean 'msg_size'? [-Werror=implicit-function-declaration]
     return page_size(page) >> inode->i_blkbits;
            ^~~~~~~~~
            msg_size
   cc1: some warnings being treated as errors
--
   In file included from include/linux/blkdev.h:16:0,
                    from include/linux/blk-cgroup.h:21,
                    from include/linux/writeback.h:14,
                    from include/linux/memcontrol.h:22,
                    from include/net/sock.h:53,
                    from net//tipc/socket.h:38,
                    from net//tipc/trace.h:45,
                    from net//tipc/trace.c:37:
   include/linux/pagemap.h: In function 'i_blocks_per_page':
>> include/linux/pagemap.h:640:9: error: implicit declaration of function 'page_size'; did you mean 'msg_size'? [-Werror=implicit-function-declaration]
     return page_size(page) >> inode->i_blkbits;
            ^~~~~~~~~
            msg_size
   In file included from net//tipc/trace.h:431:0,
                    from net//tipc/trace.c:37:
   include/trace/define_trace.h: At top level:
   include/trace/define_trace.h:95:42: fatal error: ./trace.h: No such file or directory
    #include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
                                             ^
   cc1: some warnings being treated as errors
   compilation terminated.
--
   In file included from include/linux/blkdev.h:16:0,
                    from include/linux/blk-cgroup.h:21,
                    from include/linux/writeback.h:14,
                    from include/linux/memcontrol.h:22,
                    from include/net/sock.h:53,
                    from include/linux/tcp.h:19,
                    from include/linux/ipv6.h:87,
                    from include/net/ipv6.h:12,
                    from include/rdma/ib_verbs.h:51,
                    from include/linux/lsm_audit.h:25,
                    from security//apparmor/include/audit.h:16,
                    from security//apparmor/include/policy.h:23,
                    from security//apparmor/include/policy_ns.h:19,
                    from security//apparmor/include/cred.h:19,
                    from security//apparmor/task.c:15:
   include/linux/pagemap.h: In function 'i_blocks_per_page':
>> include/linux/pagemap.h:640:9: error: implicit declaration of function 'page_size'; did you mean 'table_size'? [-Werror=implicit-function-declaration]
     return page_size(page) >> inode->i_blkbits;
            ^~~~~~~~~
            table_size
   cc1: some warnings being treated as errors
--
   In file included from include/linux/blkdev.h:16:0,
                    from include/linux/blk-cgroup.h:21,
                    from include/linux/writeback.h:14,
                    from include/linux/memcontrol.h:22,
                    from include/net/sock.h:53,
                    from include/linux/tcp.h:19,
                    from include/linux/ipv6.h:87,
                    from include/net/ipv6.h:12,
                    from include/rdma/ib_verbs.h:51,
                    from include/linux/lsm_audit.h:25,
                    from security//apparmor/include/audit.h:16,
                    from security//apparmor/include/policy.h:23,
                    from security//apparmor/include/policy_ns.h:19,
                    from security//apparmor/include/cred.h:19,
                    from security//apparmor/capability.c:18:
   include/linux/pagemap.h: In function 'i_blocks_per_page':
>> include/linux/pagemap.h:640:9: error: implicit declaration of function 'page_size'; did you mean 'table_size'? [-Werror=implicit-function-declaration]
     return page_size(page) >> inode->i_blkbits;
            ^~~~~~~~~
            table_size
   security//apparmor/capability.c: At top level:
   security//apparmor/capability.c:25:10: fatal error: capability_names.h: No such file or directory
    #include "capability_names.h"
             ^~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors
   compilation terminated.

vim +640 include/linux/pagemap.h

   628	
   629	/**
   630	 * i_blocks_per_page - How many blocks fit in this page.
   631	 * @inode: The inode which contains the blocks.
   632	 * @page: The (potentially large) page.
   633	 *
   634	 * Context: Any context.
   635	 * Return: The number of filesystem blocks covered by this page.
   636	 */
   637	static inline
   638	unsigned int i_blocks_per_page(struct inode *inode, struct page *page)
   639	{
 > 640		return page_size(page) >> inode->i_blkbits;

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
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Re: [PATCH v2 3/5] iomap: Support large pages

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 2747 bytes --]

Hi Matthew,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[cannot apply to v5.3-rc5 next-20190823]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Matthew-Wilcox/iomap-xfs-support-for-large-pages/20190823-191138
config: c6x-allyesconfig (attached as .config)
compiler: c6x-elf-gcc (GCC) 7.4.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.4.0 make.cross ARCH=c6x 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from include/linux/blkdev.h:16:0,
                    from include/linux/iomap.h:10,
                    from fs/iomap/buffered-io.c:9:
   include/linux/pagemap.h: In function 'file_offset_of_next_page':
   include/linux/pagemap.h:445:32: error: implicit declaration of function 'compound_nr'; did you mean 'compound_order'? [-Werror=implicit-function-declaration]
     return ((loff_t)page->index + compound_nr(page)) << PAGE_SHIFT;
                                   ^~~~~~~~~~~
                                   compound_order
   include/linux/pagemap.h: In function 'i_blocks_per_page':
   include/linux/pagemap.h:659:9: error: implicit declaration of function 'page_size'; did you mean 'page_zone'? [-Werror=implicit-function-declaration]
     return page_size(page) >> inode->i_blkbits;
            ^~~~~~~~~
            page_zone
   fs/iomap/buffered-io.c: In function 'iomap_nr_vecs':
>> fs/iomap/buffered-io.c:213:43: error: implicit declaration of function 'page_shift'; did you mean 'page_pgdat'? [-Werror=implicit-function-declaration]
     return (length + page_size(page) - 1) >> page_shift(page);
                                              ^~~~~~~~~~
                                              page_pgdat
   cc1: some warnings being treated as errors

vim +213 fs/iomap/buffered-io.c

   205	
   206	/*
   207	 * Estimate the number of vectors we need based on the current page size;
   208	 * if we're wrong we'll end up doing an overly large allocation or needing
   209	 * to do a second allocation, neither of which is a big deal.
   210	 */
   211	static unsigned int iomap_nr_vecs(struct page *page, loff_t length)
   212	{
 > 213		return (length + page_size(page) - 1) >> page_shift(page);
   214	}
   215	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 49703 bytes --]

Re: [PATCH v2 2/5] mm: Add file_offset_of_ helpers

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 2696 bytes --]

Hi Matthew,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[cannot apply to v5.3-rc5 next-20190823]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Matthew-Wilcox/iomap-xfs-support-for-large-pages/20190823-191138
config: i386-defconfig (attached as .config)
compiler: gcc-7 (Debian 7.4.0-10) 7.4.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from include/linux/blkdev.h:16:0,
                    from include/linux/blk-cgroup.h:21,
                    from include/linux/writeback.h:14,
                    from include/linux/memcontrol.h:22,
                    from include/linux/swap.h:9,
                    from include/linux/suspend.h:5,
                    from arch/x86/kernel/asm-offsets.c:13:
   include/linux/pagemap.h: In function 'file_offset_of_next_page':
>> include/linux/pagemap.h:445:32: error: implicit declaration of function 'compound_nr'; did you mean 'compound_order'? [-Werror=implicit-function-declaration]
     return ((loff_t)page->index + compound_nr(page)) << PAGE_SHIFT;
                                   ^~~~~~~~~~~
                                   compound_order
   include/linux/pagemap.h: In function 'i_blocks_per_page':
   include/linux/pagemap.h:659:9: error: implicit declaration of function 'page_size'; did you mean 'page_zone'? [-Werror=implicit-function-declaration]
     return page_size(page) >> inode->i_blkbits;
            ^~~~~~~~~
            page_zone
   cc1: some warnings being treated as errors
   make[2]: *** [arch/x86/kernel/asm-offsets.s] Error 1
   make[2]: Target '__build' not remade because of errors.
   make[1]: *** [prepare0] Error 2
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [sub-make] Error 2
   16 real  6 user  2 sys  56.01% cpu 	make prepare

vim +445 include/linux/pagemap.h

   435	
   436	/**
   437	 * file_offset_of_next_page - File offset of the next page.
   438	 * @page: Page cache page.
   439	 *
   440	 * Context: Any context.
   441	 * Return: The offset of the first byte after this page.
   442	 */
   443	static inline loff_t file_offset_of_next_page(struct page *page)
   444	{
 > 445		return ((loff_t)page->index + compound_nr(page)) << PAGE_SHIFT;
   446	}
   447	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 28074 bytes --]

Re: [PATCH v2 2/5] mm: Add file_offset_of_ helpers

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 2284 bytes --]

Hi Matthew,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on linus/master]
[cannot apply to v5.3-rc5 next-20190823]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Matthew-Wilcox/iomap-xfs-support-for-large-pages/20190823-191138
config: x86_64-randconfig-f001-201933 (attached as .config)
compiler: gcc-7 (Debian 7.4.0-10) 7.4.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   In file included from arch/x86/include/asm/pgalloc.h:7:0,
                    from include/asm-generic/tlb.h:16,
                    from arch/x86/include/asm/tlb.h:12,
                    from arch/x86/include/asm/efi.h:8,
                    from drivers/firmware/efi/libstub/tpm.c:12:
   include/linux/pagemap.h: In function 'file_offset_of_next_page':
>> include/linux/pagemap.h:445:32: warning: implicit declaration of function 'compound_nr'; did you mean 'compound_order'? [-Wimplicit-function-declaration]
     return ((loff_t)page->index + compound_nr(page)) << PAGE_SHIFT;
                                   ^~~~~~~~~~~
                                   compound_order
   include/linux/pagemap.h: In function 'i_blocks_per_page':
   include/linux/pagemap.h:659:9: warning: implicit declaration of function 'page_size'; did you mean 'page_zone'? [-Wimplicit-function-declaration]
     return page_size(page) >> inode->i_blkbits;
            ^~~~~~~~~
            page_zone

vim +445 include/linux/pagemap.h

   435	
   436	/**
   437	 * file_offset_of_next_page - File offset of the next page.
   438	 * @page: Page cache page.
   439	 *
   440	 * Context: Any context.
   441	 * Return: The offset of the first byte after this page.
   442	 */
   443	static inline loff_t file_offset_of_next_page(struct page *page)
   444	{
 > 445		return ((loff_t)page->index + compound_nr(page)) << PAGE_SHIFT;
   446	}
   447	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 31936 bytes --]

Re: [PATCH v2 2/5] mm: Add file_offset_of_ helpers

[Matthew Wilcox]

On Sat, Aug 24, 2019 at 07:48:24PM +0800, kbuild test robot wrote:
> Hi Matthew,
> 
> Thank you for the patch! Perhaps something to improve:
> 
> [auto build test WARNING on linus/master]
> [cannot apply to v5.3-rc5 next-20190823]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

It depends on various patches which are in -next, although I didn't
generate them against -next.

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

[Darrick J. Wong]

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
> 

Re: [PATCH v2 2/5] mm: Add file_offset_of_ helpers

[Darrick J. Wong]

On Tue, Aug 20, 2019 at 05:30:36PM -0700, Matthew Wilcox wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> The page_offset function is badly named for people reading the functions
> which call it.  The natural meaning of a function with this name would
> be 'offset within a page', not 'page offset in bytes within a file'.
> Dave Chinner suggests file_offset_of_page() as a replacement function
> name and I'm also adding file_offset_of_next_page() as a helper for the
> large page work.  Also add kernel-doc for these functions so they show
> up in the kernel API book.
> 
> page_offset() is retained as a compatibility define for now.

No SOB?

Looks fine to me, and I appreciate the much less confusing name.  I was
hoping for a page_offset conversion for fs/iomap/ (and not a treewide
change because yuck), but I guess that can be done if and when this
lands.

--D

> ---
>  include/linux/pagemap.h | 25 ++++++++++++++++++++++---
>  1 file changed, 22 insertions(+), 3 deletions(-)
> 
> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> index 2728f20fbc49..84f341109710 100644
> --- a/include/linux/pagemap.h
> +++ b/include/linux/pagemap.h
> @@ -436,14 +436,33 @@ static inline pgoff_t page_to_pgoff(struct page *page)
>  	return page_to_index(page);
>  }
>  
> -/*
> - * Return byte-offset into filesystem object for page.
> +/**
> + * file_offset_of_page - File offset of this page.
> + * @page: Page cache page.
> + *
> + * Context: Any context.
> + * Return: The offset of the first byte of this page.
>   */
> -static inline loff_t page_offset(struct page *page)
> +static inline loff_t file_offset_of_page(struct page *page)
>  {
>  	return ((loff_t)page->index) << PAGE_SHIFT;
>  }
>  
> +/* Legacy; please convert callers */
> +#define page_offset(page)	file_offset_of_page(page)
> +
> +/**
> + * file_offset_of_next_page - File offset of the next page.
> + * @page: Page cache page.
> + *
> + * Context: Any context.
> + * Return: The offset of the first byte after this page.
> + */
> +static inline loff_t file_offset_of_next_page(struct page *page)
> +{
> +	return ((loff_t)page->index + compound_nr(page)) << PAGE_SHIFT;
> +}
> +
>  static inline loff_t page_file_offset(struct page *page)
>  {
>  	return ((loff_t)page_index(page)) << PAGE_SHIFT;
> -- 
> 2.23.0.rc1
> 

Re: [PATCH v2 3/5] iomap: Support large pages

[Darrick J. Wong]

On Tue, Aug 20, 2019 at 05:30:37PM -0700, Matthew Wilcox wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> Change iomap_page from a statically sized uptodate bitmap to a dynamically
> allocated uptodate bitmap, allowing an arbitrarily large page.
> 
> The only remaining places where iomap assumes an order-0 page are for
> files with inline data, where there's no sense in allocating a larger
> page.

I wonder, will anything bad happen if that occurs?  (XFS doesn't have
inline data for files so I have no idea...)

> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>  fs/iomap/buffered-io.c | 119 ++++++++++++++++++++++++++---------------
>  include/linux/iomap.h  |   2 +-
>  include/linux/mm.h     |   2 +
>  3 files changed, 80 insertions(+), 43 deletions(-)
> 
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index 0e76a4b6d98a..15d844a88439 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -23,14 +23,14 @@ static struct iomap_page *
>  iomap_page_create(struct inode *inode, struct page *page)
>  {
>  	struct iomap_page *iop = to_iomap_page(page);
> +	unsigned int n;
>  
>  	if (iop || i_blocks_per_page(inode, page) <= 1)
>  		return iop;
>  
> -	iop = kmalloc(sizeof(*iop), GFP_NOFS | __GFP_NOFAIL);
> -	atomic_set(&iop->read_count, 0);
> -	atomic_set(&iop->write_count, 0);
> -	bitmap_zero(iop->uptodate, PAGE_SIZE / SECTOR_SIZE);
> +	n = BITS_TO_LONGS(i_blocks_per_page(inode, page));
> +	iop = kmalloc(struct_size(iop, uptodate, n),
> +			GFP_NOFS | __GFP_NOFAIL | __GFP_ZERO);
>  
>  	/*
>  	 * migrate_page_move_mapping() assumes that pages with private data have
> @@ -61,15 +61,16 @@ iomap_page_release(struct page *page)
>   * Calculate the range inside the page that we actually need to read.
>   */
>  static void
> -iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop,
> +iomap_adjust_read_range(struct inode *inode, struct page *page,
>  		loff_t *pos, loff_t length, unsigned *offp, unsigned *lenp)
>  {
> +	struct iomap_page *iop = to_iomap_page(page);
>  	loff_t orig_pos = *pos;
>  	loff_t isize = i_size_read(inode);
>  	unsigned block_bits = inode->i_blkbits;
>  	unsigned block_size = (1 << block_bits);
> -	unsigned poff = offset_in_page(*pos);
> -	unsigned plen = min_t(loff_t, PAGE_SIZE - poff, length);
> +	unsigned poff = offset_in_this_page(page, *pos);
> +	unsigned plen = min_t(loff_t, page_size(page) - poff, length);
>  	unsigned first = poff >> block_bits;
>  	unsigned last = (poff + plen - 1) >> block_bits;
>  
> @@ -107,7 +108,8 @@ iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop,
>  	 * page cache for blocks that are entirely outside of i_size.
>  	 */
>  	if (orig_pos <= isize && orig_pos + length > isize) {
> -		unsigned end = offset_in_page(isize - 1) >> block_bits;
> +		unsigned end = offset_in_this_page(page, isize - 1) >>
> +				block_bits;
>  
>  		if (first <= end && last > end)
>  			plen -= (last - end) * block_size;
> @@ -121,19 +123,16 @@ static void
>  iomap_set_range_uptodate(struct page *page, unsigned off, unsigned len)
>  {
>  	struct iomap_page *iop = to_iomap_page(page);
> -	struct inode *inode = page->mapping->host;
> -	unsigned first = off >> inode->i_blkbits;
> -	unsigned last = (off + len - 1) >> inode->i_blkbits;
> -	unsigned int i;
>  	bool uptodate = true;
>  
>  	if (iop) {
> -		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))
> -				uptodate = false;
> -		}
> +		struct inode *inode = page->mapping->host;
> +		unsigned first = off >> inode->i_blkbits;
> +		unsigned count = len >> inode->i_blkbits;
> +
> +		bitmap_set(iop->uptodate, first, count);
> +		if (!bitmap_full(iop->uptodate, i_blocks_per_page(inode, page)))
> +			uptodate = false;
>  	}
>  
>  	if (uptodate && !PageError(page))
> @@ -194,6 +193,7 @@ iomap_read_inline_data(struct inode *inode, struct page *page,
>  		return;
>  
>  	BUG_ON(page->index);
> +	BUG_ON(PageCompound(page));
>  	BUG_ON(size > PAGE_SIZE - offset_in_page(iomap->inline_data));
>  
>  	addr = kmap_atomic(page);
> @@ -203,6 +203,16 @@ iomap_read_inline_data(struct inode *inode, struct page *page,
>  	SetPageUptodate(page);
>  }
>  
> +/*
> + * Estimate the number of vectors we need based on the current page size;
> + * if we're wrong we'll end up doing an overly large allocation or needing
> + * to do a second allocation, neither of which is a big deal.
> + */
> +static unsigned int iomap_nr_vecs(struct page *page, loff_t length)
> +{
> +	return (length + page_size(page) - 1) >> page_shift(page);
> +}
> +
>  static loff_t
>  iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
>  		struct iomap *iomap)
> @@ -222,7 +232,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
>  	}
>  
>  	/* zero post-eof blocks as the page may be mapped */
> -	iomap_adjust_read_range(inode, iop, &pos, length, &poff, &plen);
> +	iomap_adjust_read_range(inode, page, &pos, length, &poff, &plen);
>  	if (plen == 0)
>  		goto done;
>  
> @@ -258,7 +268,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
>  
>  	if (!ctx->bio || !is_contig || bio_full(ctx->bio, plen)) {
>  		gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL);
> -		int nr_vecs = (length + PAGE_SIZE - 1) >> PAGE_SHIFT;
> +		int nr_vecs = iomap_nr_vecs(page, length);
>  
>  		if (ctx->bio)
>  			submit_bio(ctx->bio);
> @@ -293,9 +303,9 @@ iomap_readpage(struct page *page, const struct iomap_ops *ops)
>  	unsigned poff;
>  	loff_t ret;
>  
> -	for (poff = 0; poff < PAGE_SIZE; poff += ret) {
> -		ret = iomap_apply(inode, page_offset(page) + poff,
> -				PAGE_SIZE - poff, 0, ops, &ctx,
> +	for (poff = 0; poff < page_size(page); poff += ret) {
> +		ret = iomap_apply(inode, file_offset_of_page(page) + poff,
> +				page_size(page) - poff, 0, ops, &ctx,
>  				iomap_readpage_actor);
>  		if (ret <= 0) {
>  			WARN_ON_ONCE(ret == 0);
> @@ -328,7 +338,7 @@ iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos,
>  	while (!list_empty(pages)) {
>  		struct page *page = lru_to_page(pages);
>  
> -		if (page_offset(page) >= (u64)pos + length)
> +		if (file_offset_of_page(page) >= (u64)pos + length)
>  			break;
>  
>  		list_del(&page->lru);
> @@ -342,7 +352,7 @@ iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos,
>  		 * readpages call itself as every page gets checked again once
>  		 * actually needed.
>  		 */
> -		*done += PAGE_SIZE;
> +		*done += page_size(page);
>  		put_page(page);
>  	}
>  
> @@ -355,9 +365,14 @@ iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length,
>  {
>  	struct iomap_readpage_ctx *ctx = data;
>  	loff_t done, ret;
> +	size_t left = 0;
> +
> +	if (ctx->cur_page)
> +		left = page_size(ctx->cur_page) -
> +					offset_in_this_page(ctx->cur_page, pos);
>  
>  	for (done = 0; done < length; done += ret) {
> -		if (ctx->cur_page && offset_in_page(pos + done) == 0) {
> +		if (ctx->cur_page && left == 0) {
>  			if (!ctx->cur_page_in_bio)
>  				unlock_page(ctx->cur_page);
>  			put_page(ctx->cur_page);
> @@ -369,14 +384,27 @@ iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length,
>  			if (!ctx->cur_page)
>  				break;
>  			ctx->cur_page_in_bio = false;
> +			left = page_size(ctx->cur_page);
>  		}
>  		ret = iomap_readpage_actor(inode, pos + done, length - done,
>  				ctx, iomap);
> +		left -= ret;
>  	}
>  
>  	return done;
>  }
>  
> +/* move to fs.h? */
> +static inline struct page *readahead_first_page(struct list_head *head)
> +{
> +	return list_entry(head->prev, struct page, lru);
> +}
> +
> +static inline struct page *readahead_last_page(struct list_head *head)
> +{
> +	return list_entry(head->next, struct page, lru);
> +}
> +
>  int
>  iomap_readpages(struct address_space *mapping, struct list_head *pages,
>  		unsigned nr_pages, const struct iomap_ops *ops)
> @@ -385,9 +413,10 @@ iomap_readpages(struct address_space *mapping, struct list_head *pages,
>  		.pages		= pages,
>  		.is_readahead	= true,
>  	};
> -	loff_t pos = page_offset(list_entry(pages->prev, struct page, lru));
> -	loff_t last = page_offset(list_entry(pages->next, struct page, lru));
> -	loff_t length = last - pos + PAGE_SIZE, ret = 0;
> +	loff_t pos = file_offset_of_page(readahead_first_page(pages));
> +	loff_t end = file_offset_of_next_page(readahead_last_page(pages));
> +	loff_t length = end - pos;
> +	loff_t ret = 0;
>  
>  	while (length > 0) {
>  		ret = iomap_apply(mapping->host, pos, length, 0, ops,
> @@ -410,7 +439,7 @@ iomap_readpages(struct address_space *mapping, struct list_head *pages,
>  	}
>  
>  	/*
> -	 * Check that we didn't lose a page due to the arcance calling
> +	 * Check that we didn't lose a page due to the arcane calling
>  	 * conventions..
>  	 */
>  	WARN_ON_ONCE(!ret && !list_empty(ctx.pages));
> @@ -435,7 +464,7 @@ iomap_is_partially_uptodate(struct page *page, unsigned long from,
>  	unsigned i;
>  
>  	/* Limit range to one page */
> -	len = min_t(unsigned, PAGE_SIZE - from, count);
> +	len = min_t(unsigned, page_size(page) - from, count);
>  
>  	/* First and last blocks in range within page */
>  	first = from >> inode->i_blkbits;
> @@ -474,7 +503,7 @@ iomap_invalidatepage(struct page *page, unsigned int offset, unsigned int len)
>  	 * If we are invalidating the entire page, clear the dirty state from it
>  	 * and release it to avoid unnecessary buildup of the LRU.
>  	 */
> -	if (offset == 0 && len == PAGE_SIZE) {
> +	if (offset == 0 && len == page_size(page)) {
>  		WARN_ON_ONCE(PageWriteback(page));
>  		cancel_dirty_page(page);
>  		iomap_page_release(page);
> @@ -550,18 +579,20 @@ static int
>  __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len,
>  		struct page *page, struct iomap *iomap)
>  {
> -	struct iomap_page *iop = iomap_page_create(inode, page);
>  	loff_t block_size = i_blocksize(inode);
>  	loff_t block_start = pos & ~(block_size - 1);
>  	loff_t block_end = (pos + len + block_size - 1) & ~(block_size - 1);
> -	unsigned from = offset_in_page(pos), to = from + len, poff, plen;
> +	unsigned from = offset_in_this_page(page, pos);
> +	unsigned to = from + len;
> +	unsigned poff, plen;
>  	int status = 0;
>  
>  	if (PageUptodate(page))
>  		return 0;
> +	iomap_page_create(inode, page);
>  
>  	do {
> -		iomap_adjust_read_range(inode, iop, &block_start,
> +		iomap_adjust_read_range(inode, page, &block_start,
>  				block_end - block_start, &poff, &plen);
>  		if (plen == 0)
>  			break;
> @@ -673,7 +704,7 @@ __iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
>  	 */
>  	if (unlikely(copied < len && !PageUptodate(page)))
>  		return 0;
> -	iomap_set_range_uptodate(page, offset_in_page(pos), len);
> +	iomap_set_range_uptodate(page, offset_in_this_page(page, pos), len);
>  	iomap_set_page_dirty(page);
>  	return copied;
>  }
> @@ -685,6 +716,7 @@ iomap_write_end_inline(struct inode *inode, struct page *page,
>  	void *addr;
>  
>  	WARN_ON_ONCE(!PageUptodate(page));
> +	BUG_ON(PageCompound(page));
>  	BUG_ON(pos + copied > PAGE_SIZE - offset_in_page(iomap->inline_data));
>  
>  	addr = kmap_atomic(page);
> @@ -749,6 +781,10 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
>  		unsigned long bytes;	/* Bytes to write to page */
>  		size_t copied;		/* Bytes copied from user */
>  
> +		/*
> +		 * XXX: We don't know what size page we'll find in the
> +		 * page cache, so only copy up to a regular page boundary.

How might we fix this?

> +		 */
>  		offset = offset_in_page(pos);
>  		bytes = min_t(unsigned long, PAGE_SIZE - offset,
>  						iov_iter_count(i));
> @@ -1041,19 +1077,18 @@ vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops)
>  	lock_page(page);
>  	size = i_size_read(inode);
>  	if ((page->mapping != inode->i_mapping) ||
> -	    (page_offset(page) > size)) {
> +	    (file_offset_of_page(page) > size)) {
>  		/* We overload EFAULT to mean page got truncated */
>  		ret = -EFAULT;
>  		goto out_unlock;
>  	}
>  
> -	/* page is wholly or partially inside EOF */
> -	if (((page->index + 1) << PAGE_SHIFT) > size)
> -		length = offset_in_page(size);
> +	offset = file_offset_of_page(page);
> +	if (size - offset < page_size(page))
> +		length = offset_in_this_page(page, size);
>  	else
> -		length = PAGE_SIZE;
> +		length = page_size(page);
>  
> -	offset = page_offset(page);
>  	while (length > 0) {
>  		ret = iomap_apply(inode, offset, length,
>  				IOMAP_WRITE | IOMAP_FAULT, ops, page,
> diff --git a/include/linux/iomap.h b/include/linux/iomap.h
> index bc499ceae392..86be24a8259b 100644
> --- a/include/linux/iomap.h
> +++ b/include/linux/iomap.h
> @@ -139,7 +139,7 @@ loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length,
>  struct iomap_page {
>  	atomic_t		read_count;
>  	atomic_t		write_count;
> -	DECLARE_BITMAP(uptodate, PAGE_SIZE / 512);
> +	unsigned long		uptodate[];
>  };
>  
>  static inline struct iomap_page *to_iomap_page(struct page *page)
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 726d7f046b49..6892cd712428 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -1414,6 +1414,8 @@ static inline void clear_page_pfmemalloc(struct page *page)
>  extern void pagefault_out_of_memory(void);
>  
>  #define offset_in_page(p)	((unsigned long)(p) & ~PAGE_MASK)
> +#define offset_in_this_page(page, p)	\
> +	((unsigned long)(p) & (page_size(page) - 1))

What's the difference between these two macros?  I guess the macro with
the longer name works for compound pages?  Whereas the first one only
works with order-0 pages?

--D

>  
>  /*
>   * Flags passed to show_mem() and show_free_areas() to suppress output in
> -- 
> 2.23.0.rc1
> 

Re: [PATCH v2 4/5] xfs: Support large pages

[Darrick J. Wong]

On Tue, Aug 20, 2019 at 05:30:38PM -0700, Matthew Wilcox wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> Mostly this is just checking the page size of each page instead of
> assuming PAGE_SIZE.  Clean up the logic in writepage a little.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Looks ok, let's see what happens when I get back to the "make xfs use
iomap writeback" series...

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

--D

> ---
>  fs/xfs/xfs_aops.c | 19 +++++++++----------
>  1 file changed, 9 insertions(+), 10 deletions(-)
> 
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index 102cfd8a97d6..1a26e9ca626b 100644
> --- a/fs/xfs/xfs_aops.c
> +++ b/fs/xfs/xfs_aops.c
> @@ -765,7 +765,7 @@ xfs_add_to_ioend(
>  	struct xfs_mount	*mp = ip->i_mount;
>  	struct block_device	*bdev = xfs_find_bdev_for_inode(inode);
>  	unsigned		len = i_blocksize(inode);
> -	unsigned		poff = offset & (PAGE_SIZE - 1);
> +	unsigned		poff = offset & (page_size(page) - 1);
>  	bool			merged, same_page = false;
>  	sector_t		sector;
>  
> @@ -843,7 +843,7 @@ xfs_aops_discard_page(
>  	if (error && !XFS_FORCED_SHUTDOWN(mp))
>  		xfs_alert(mp, "page discard unable to remove delalloc mapping.");
>  out_invalidate:
> -	xfs_vm_invalidatepage(page, 0, PAGE_SIZE);
> +	xfs_vm_invalidatepage(page, 0, page_size(page));
>  }
>  
>  /*
> @@ -984,8 +984,7 @@ xfs_do_writepage(
>  	struct xfs_writepage_ctx *wpc = data;
>  	struct inode		*inode = page->mapping->host;
>  	loff_t			offset;
> -	uint64_t              end_offset;
> -	pgoff_t                 end_index;
> +	uint64_t		end_offset;
>  
>  	trace_xfs_writepage(inode, page, 0, 0);
>  
> @@ -1024,10 +1023,9 @@ xfs_do_writepage(
>  	 * ---------------------------------^------------------|
>  	 */
>  	offset = i_size_read(inode);
> -	end_index = offset >> PAGE_SHIFT;
> -	if (page->index < end_index)
> -		end_offset = (xfs_off_t)(page->index + 1) << PAGE_SHIFT;
> -	else {
> +	end_offset = file_offset_of_next_page(page);
> +
> +	if (end_offset > offset) {
>  		/*
>  		 * Check whether the page to write out is beyond or straddles
>  		 * i_size or not.
> @@ -1039,7 +1037,8 @@ xfs_do_writepage(
>  		 * |				    |      Straddles     |
>  		 * ---------------------------------^-----------|--------|
>  		 */
> -		unsigned offset_into_page = offset & (PAGE_SIZE - 1);
> +		unsigned offset_into_page = offset_in_this_page(page, offset);
> +		pgoff_t end_index = offset >> PAGE_SHIFT;
>  
>  		/*
>  		 * Skip the page if it is fully outside i_size, e.g. due to a
> @@ -1070,7 +1069,7 @@ xfs_do_writepage(
>  		 * memory is zeroed when mapped, and writes to that region are
>  		 * not written out to the file."
>  		 */
> -		zero_user_segment(page, offset_into_page, PAGE_SIZE);
> +		zero_user_segment(page, offset_into_page, page_size(page));
>  
>  		/* Adjust the end_offset to the end of file */
>  		end_offset = offset;
> -- 
> 2.23.0.rc1
> 

Re: [PATCH v2 5/5] xfs: Pass a page to xfs_finish_page_writeback

[Darrick J. Wong]

On Tue, Aug 20, 2019 at 05:30:39PM -0700, Matthew Wilcox wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> The only part of the bvec we were accessing was the bv_page, so just
> pass that instead of the whole bvec.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

Seems fine but same caveats about tree churn as the previous patch.

--D

> ---
>  fs/xfs/xfs_aops.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> index 1a26e9ca626b..edcb4797fcc2 100644
> --- a/fs/xfs/xfs_aops.c
> +++ b/fs/xfs/xfs_aops.c
> @@ -58,21 +58,21 @@ xfs_find_daxdev_for_inode(
>  static void
>  xfs_finish_page_writeback(
>  	struct inode		*inode,
> -	struct bio_vec	*bvec,
> +	struct page		*page,
>  	int			error)
>  {
> -	struct iomap_page	*iop = to_iomap_page(bvec->bv_page);
> +	struct iomap_page	*iop = to_iomap_page(page);
>  
>  	if (error) {
> -		SetPageError(bvec->bv_page);
> +		SetPageError(page);
>  		mapping_set_error(inode->i_mapping, -EIO);
>  	}
>  
> -	ASSERT(iop || i_blocks_per_page(inode, bvec->bv_page) <= 1);
> +	ASSERT(iop || i_blocks_per_page(inode, page) <= 1);
>  	ASSERT(!iop || atomic_read(&iop->write_count) > 0);
>  
>  	if (!iop || atomic_dec_and_test(&iop->write_count))
> -		end_page_writeback(bvec->bv_page);
> +		end_page_writeback(page);
>  }
>  
>  /*
> @@ -106,7 +106,7 @@ xfs_destroy_ioend(
>  
>  		/* walk each page on bio, ending page IO on them */
>  		bio_for_each_segment_all(bvec, bio, iter_all)
> -			xfs_finish_page_writeback(inode, bvec, error);
> +			xfs_finish_page_writeback(inode, bvec->bv_page, error);
>  		bio_put(bio);
>  	}
>  
> -- 
> 2.23.0.rc1
> 

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

[Matthew Wilcox]

On Wed, Sep 18, 2019 at 02:14:39PM -0700, Darrick J. Wong wrote:
> 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?)

It doesn't apply patches on top of the -mm tree for some reason.  So
it has no idea about the page_size() macro that's sitting in -mm at the
moment.

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

Thanks.

Re: [PATCH v2 2/5] mm: Add file_offset_of_ helpers

[Matthew Wilcox]

On Wed, Sep 18, 2019 at 02:17:55PM -0700, Darrick J. Wong wrote:
> On Tue, Aug 20, 2019 at 05:30:36PM -0700, Matthew Wilcox wrote:
> > From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> > 
> > The page_offset function is badly named for people reading the functions
> > which call it.  The natural meaning of a function with this name would
> > be 'offset within a page', not 'page offset in bytes within a file'.
> > Dave Chinner suggests file_offset_of_page() as a replacement function
> > name and I'm also adding file_offset_of_next_page() as a helper for the
> > large page work.  Also add kernel-doc for these functions so they show
> > up in the kernel API book.
> > 
> > page_offset() is retained as a compatibility define for now.
> 
> No SOB?
> 
> Looks fine to me, and I appreciate the much less confusing name.  I was
> hoping for a page_offset conversion for fs/iomap/ (and not a treewide
> change because yuck), but I guess that can be done if and when this
> lands.

Sure, I'll do that once everything else has landed.

Re: [PATCH v2 2/5] mm: Add file_offset_of_ helpers

[Darrick J. Wong]

[add dave to cc]

On Wed, Sep 18, 2019 at 04:49:24PM -0700, Matthew Wilcox wrote:
> On Wed, Sep 18, 2019 at 02:17:55PM -0700, Darrick J. Wong wrote:
> > On Tue, Aug 20, 2019 at 05:30:36PM -0700, Matthew Wilcox wrote:
> > > From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> > > 
> > > The page_offset function is badly named for people reading the functions
> > > which call it.  The natural meaning of a function with this name would
> > > be 'offset within a page', not 'page offset in bytes within a file'.
> > > Dave Chinner suggests file_offset_of_page() as a replacement function
> > > name and I'm also adding file_offset_of_next_page() as a helper for the
> > > large page work.  Also add kernel-doc for these functions so they show
> > > up in the kernel API book.
> > > 
> > > page_offset() is retained as a compatibility define for now.
> > 
> > No SOB?
> > 
> > Looks fine to me, and I appreciate the much less confusing name.  I was
> > hoping for a page_offset conversion for fs/iomap/ (and not a treewide
> > change because yuck), but I guess that can be done if and when this
> > lands.
> 
> Sure, I'll do that once everything else has landed.

You might also want to ask Dave Chinner what changes he's making to
iomap to support blocksize > pagesize filesystems, since that's
/definitely/ going to clash. :)

--D