afs: Use folios in directory handling

Convert the AFS directory handling code to use folios.

With these changes, afs passes -g quick xfstests.

Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: kafs-testing@auristor.com
cc: Matthew Wilcox (Oracle) <willy@infradead.org>
cc: Jeff Layton <jlayton@kernel.org>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/162877312172.3085614.992850861791211206.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/162981154845.1901565.2078707403143240098.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/163005746215.2472992.8321380998443828308.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163584190457.4023316.10544419117563104940.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/CAH2r5mtECQA6K_OGgU=_G8qLY3G-6-jo1odVyF9EK+O2-EWLFg@mail.gmail.com/ # v3
Link: https://lore.kernel.org/r/163649330345.309189.11182522282723655658.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/163657854055.834781.5800946340537517009.stgit@warthog.procyon.org.uk/ # v5

1 files changed, 95 insertions, 134 deletions

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 4579bbda4634..da9b4f8577a1 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -103,13 +103,13 @@ struct afs_lookup_cookie {
 };
 
 /*
- * Drop the refs that we're holding on the pages we were reading into.  We've
+ * Drop the refs that we're holding on the folios we were reading into.  We've
  * got refs on the first nr_pages pages.
  */
 static void afs_dir_read_cleanup(struct afs_read *req)
 {
 	struct address_space *mapping = req->vnode->vfs_inode.i_mapping;
-	struct page *page;
+	struct folio *folio;
 	pgoff_t last = req->nr_pages - 1;
 
 	XA_STATE(xas, &mapping->i_pages, 0);
@@ -118,65 +118,56 @@ static void afs_dir_read_cleanup(struct afs_read *req)
 		return;
 
 	rcu_read_lock();
-	xas_for_each(&xas, page, last) {
-		if (xas_retry(&xas, page))
+	xas_for_each(&xas, folio, last) {
+		if (xas_retry(&xas, folio))
 			continue;
-		BUG_ON(xa_is_value(page));
-		BUG_ON(PageCompound(page));
-		ASSERTCMP(page->mapping, ==, mapping);
+		BUG_ON(xa_is_value(folio));
+		ASSERTCMP(folio_file_mapping(folio), ==, mapping);
 
-		put_page(page);
+		folio_put(folio);
 	}
 
 	rcu_read_unlock();
 }
 
 /*
- * check that a directory page is valid
+ * check that a directory folio is valid
  */
-static bool afs_dir_check_page(struct afs_vnode *dvnode, struct page *page,
-			       loff_t i_size)
+static bool afs_dir_check_folio(struct afs_vnode *dvnode, struct folio *folio,
+				loff_t i_size)
 {
-	struct afs_xdr_dir_page *dbuf;
-	loff_t latter, off;
-	int tmp, qty;
+	union afs_xdr_dir_block *block;
+	size_t offset, size;
+	loff_t pos;
 
-	/* Determine how many magic numbers there should be in this page, but
+	/* Determine how many magic numbers there should be in this folio, but
 	 * we must take care because the directory may change size under us.
 	 */
-	off = page_offset(page);
-	if (i_size <= off)
+	pos = folio_pos(folio);
+	if (i_size <= pos)
 		goto checked;
 
-	latter = i_size - off;
-	if (latter >= PAGE_SIZE)
-		qty = PAGE_SIZE;
-	else
-		qty = latter;
-	qty /= sizeof(union afs_xdr_dir_block);
-
-	/* check them */
-	dbuf = kmap_atomic(page);
-	for (tmp = 0; tmp < qty; tmp++) {
-		if (dbuf->blocks[tmp].hdr.magic != AFS_DIR_MAGIC) {
-			printk("kAFS: %s(%lx): bad magic %d/%d is %04hx\n",
-			       __func__, dvnode->vfs_inode.i_ino, tmp, qty,
-			       ntohs(dbuf->blocks[tmp].hdr.magic));
-			trace_afs_dir_check_failed(dvnode, off, i_size);
-			kunmap(page);
+	size = min_t(loff_t, folio_size(folio), i_size - pos);
+	for (offset = 0; offset < size; offset += sizeof(*block)) {
+		block = kmap_local_folio(folio, offset);
+		if (block->hdr.magic != AFS_DIR_MAGIC) {
+			printk("kAFS: %s(%lx): [%llx] bad magic %zx/%zx is %04hx\n",
+			       __func__, dvnode->vfs_inode.i_ino,
+			       pos, offset, size, ntohs(block->hdr.magic));
+			trace_afs_dir_check_failed(dvnode, pos + offset, i_size);
+			kunmap_local(block);
 			trace_afs_file_error(dvnode, -EIO, afs_file_error_dir_bad_magic);
 			goto error;
 		}
 
 		/* Make sure each block is NUL terminated so we can reasonably
-		 * use string functions on it.  The filenames in the page
+		 * use string functions on it.  The filenames in the folio
 		 * *should* be NUL-terminated anyway.
 		 */
-		((u8 *)&dbuf->blocks[tmp])[AFS_DIR_BLOCK_SIZE - 1] = 0;
-	}
-
-	kunmap_atomic(dbuf);
+		((u8 *)block)[AFS_DIR_BLOCK_SIZE - 1] = 0;
 
+		kunmap_local(block);
+	}
 checked:
 	afs_stat_v(dvnode, n_read_dir);
 	return true;
@@ -190,11 +181,11 @@ error:
  */
 static void afs_dir_dump(struct afs_vnode *dvnode, struct afs_read *req)
 {
-	struct afs_xdr_dir_page *dbuf;
+	union afs_xdr_dir_block *block;
 	struct address_space *mapping = dvnode->vfs_inode.i_mapping;
-	struct page *page;
-	unsigned int i, qty = PAGE_SIZE / sizeof(union afs_xdr_dir_block);
+	struct folio *folio;
 	pgoff_t last = req->nr_pages - 1;
+	size_t offset, size;
 
 	XA_STATE(xas, &mapping->i_pages, 0);
 
@@ -205,30 +196,28 @@ static void afs_dir_dump(struct afs_vnode *dvnode, struct afs_read *req)
 		req->pos, req->nr_pages,
 		req->iter->iov_offset,  iov_iter_count(req->iter));
 
-	xas_for_each(&xas, page, last) {
-		if (xas_retry(&xas, page))
+	xas_for_each(&xas, folio, last) {
+		if (xas_retry(&xas, folio))
 			continue;
 
-		BUG_ON(PageCompound(page));
-		BUG_ON(page->mapping != mapping);
-
-		dbuf = kmap_atomic(page);
-		for (i = 0; i < qty; i++) {
-			union afs_xdr_dir_block *block = &dbuf->blocks[i];
+		BUG_ON(folio_file_mapping(folio) != mapping);
 
-			pr_warn("[%02lx] %32phN\n", page->index * qty + i, block);
+		size = min_t(loff_t, folio_size(folio), req->actual_len - folio_pos(folio));
+		for (offset = 0; offset < size; offset += sizeof(*block)) {
+			block = kmap_local_folio(folio, offset);
+			pr_warn("[%02lx] %32phN\n", folio_index(folio) + offset, block);
+			kunmap_local(block);
 		}
-		kunmap_atomic(dbuf);
 	}
 }
 
 /*
- * Check all the pages in a directory.  All the pages are held pinned.
+ * Check all the blocks in a directory.  All the folios are held pinned.
  */
 static int afs_dir_check(struct afs_vnode *dvnode, struct afs_read *req)
 {
 	struct address_space *mapping = dvnode->vfs_inode.i_mapping;
-	struct page *page;
+	struct folio *folio;
 	pgoff_t last = req->nr_pages - 1;
 	int ret = 0;
 
@@ -238,14 +227,13 @@ static int afs_dir_check(struct afs_vnode *dvnode, struct afs_read *req)
 		return 0;
 
 	rcu_read_lock();
-	xas_for_each(&xas, page, last) {
-		if (xas_retry(&xas, page))
+	xas_for_each(&xas, folio, last) {
+		if (xas_retry(&xas, folio))
 			continue;
 
-		BUG_ON(PageCompound(page));
-		BUG_ON(page->mapping != mapping);
+		BUG_ON(folio_file_mapping(folio) != mapping);
 
-		if (!afs_dir_check_page(dvnode, page, req->file_size)) {
+		if (!afs_dir_check_folio(dvnode, folio, req->actual_len)) {
 			afs_dir_dump(dvnode, req);
 			ret = -EIO;
 			break;
@@ -274,15 +262,16 @@ static int afs_dir_open(struct inode *inode, struct file *file)
 
 /*
  * Read the directory into the pagecache in one go, scrubbing the previous
- * contents.  The list of pages is returned, pinning them so that they don't
+ * contents.  The list of folios is returned, pinning them so that they don't
  * get reclaimed during the iteration.
  */
 static struct afs_read *afs_read_dir(struct afs_vnode *dvnode, struct key *key)
 	__acquires(&dvnode->validate_lock)
 {
+	struct address_space *mapping = dvnode->vfs_inode.i_mapping;
 	struct afs_read *req;
 	loff_t i_size;
-	int nr_pages, i, n;
+	int nr_pages, i;
 	int ret;
 
 	_enter("");
@@ -320,43 +309,30 @@ expand:
 	req->iter = &req->def_iter;
 
 	/* Fill in any gaps that we might find where the memory reclaimer has
-	 * been at work and pin all the pages.  If there are any gaps, we will
+	 * been at work and pin all the folios.  If there are any gaps, we will
 	 * need to reread the entire directory contents.
 	 */
 	i = req->nr_pages;
 	while (i < nr_pages) {
-		struct page *pages[8], *page;
-
-		n = find_get_pages_contig(dvnode->vfs_inode.i_mapping, i,
-					  min_t(unsigned int, nr_pages - i,
-						ARRAY_SIZE(pages)),
-					  pages);
-		_debug("find %u at %u/%u", n, i, nr_pages);
-
-		if (n == 0) {
-			gfp_t gfp = dvnode->vfs_inode.i_mapping->gfp_mask;
+		struct folio *folio;
 
+		folio = filemap_get_folio(mapping, i);
+		if (!folio) {
 			if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
 				afs_stat_v(dvnode, n_inval);
 
 			ret = -ENOMEM;
-			page = __page_cache_alloc(gfp);
-			if (!page)
+			folio = __filemap_get_folio(mapping,
+						    i, FGP_LOCK | FGP_CREAT,
+						    mapping->gfp_mask);
+			if (!folio)
 				goto error;
-			ret = add_to_page_cache_lru(page,
-						    dvnode->vfs_inode.i_mapping,
-						    i, gfp);
-			if (ret < 0)
-				goto error;
-
-			attach_page_private(page, (void *)1);
-			unlock_page(page);
-			req->nr_pages++;
-			i++;
-		} else {
-			req->nr_pages += n;
-			i += n;
+			folio_attach_private(folio, (void *)1);
+			folio_unlock(folio);
 		}
+
+		req->nr_pages += folio_nr_pages(folio);
+		i += folio_nr_pages(folio);
 	}
 
 	/* If we're going to reload, we need to lock all the pages to prevent
@@ -424,7 +400,7 @@ static int afs_dir_iterate_block(struct afs_vnode *dvnode,
 	size_t nlen;
 	int tmp;
 
-	_enter("%u,%x,%p,,",(unsigned)ctx->pos,blkoff,block);
+	_enter("%llx,%x", ctx->pos, blkoff);
 
 	curr = (ctx->pos - blkoff) / sizeof(union afs_xdr_dirent);
 
@@ -513,12 +489,10 @@ static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
 			   struct key *key, afs_dataversion_t *_dir_version)
 {
 	struct afs_vnode *dvnode = AFS_FS_I(dir);
-	struct afs_xdr_dir_page *dbuf;
 	union afs_xdr_dir_block *dblock;
 	struct afs_read *req;
-	struct page *page;
-	unsigned blkoff, limit;
-	void __rcu **slot;
+	struct folio *folio;
+	unsigned offset, size;
 	int ret;
 
 	_enter("{%lu},%u,,", dir->i_ino, (unsigned)ctx->pos);
@@ -540,43 +514,30 @@ static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
 	/* walk through the blocks in sequence */
 	ret = 0;
 	while (ctx->pos < req->actual_len) {
-		blkoff = ctx->pos & ~(sizeof(union afs_xdr_dir_block) - 1);
-
-		/* Fetch the appropriate page from the directory and re-add it
+		/* Fetch the appropriate folio from the directory and re-add it
 		 * to the LRU.  We have all the pages pinned with an extra ref.
 		 */
-		rcu_read_lock();
-		page = NULL;
-		slot = radix_tree_lookup_slot(&dvnode->vfs_inode.i_mapping->i_pages,
-					      blkoff / PAGE_SIZE);
-		if (slot)
-			page = radix_tree_deref_slot(slot);
-		rcu_read_unlock();
-		if (!page) {
+		folio = __filemap_get_folio(dir->i_mapping, ctx->pos / PAGE_SIZE,
+					    FGP_ACCESSED, 0);
+		if (!folio) {
 			ret = afs_bad(dvnode, afs_file_error_dir_missing_page);
 			break;
 		}
-		mark_page_accessed(page);
 
-		limit = blkoff & ~(PAGE_SIZE - 1);
+		offset = round_down(ctx->pos, sizeof(*dblock)) - folio_file_pos(folio);
+		size = min_t(loff_t, folio_size(folio),
+			     req->actual_len - folio_file_pos(folio));
 
-		dbuf = kmap(page);
-
-		/* deal with the individual blocks stashed on this page */
 		do {
-			dblock = &dbuf->blocks[(blkoff % PAGE_SIZE) /
-					       sizeof(union afs_xdr_dir_block)];
-			ret = afs_dir_iterate_block(dvnode, ctx, dblock, blkoff);
-			if (ret != 1) {
-				kunmap(page);
+			dblock = kmap_local_folio(folio, offset);
+			ret = afs_dir_iterate_block(dvnode, ctx, dblock,
+						    folio_file_pos(folio) + offset);
+			kunmap_local(dblock);
+			if (ret != 1)
 				goto out;
-			}
 
-			blkoff += sizeof(union afs_xdr_dir_block);
+		} while (offset += sizeof(*dblock), offset < size);
 
-		} while (ctx->pos < dir->i_size && blkoff < limit);
-
-		kunmap(page);
 		ret = 0;
 	}
 
@@ -2037,42 +1998,42 @@ error:
 }
 
 /*
- * Release a directory page and clean up its private state if it's not busy
- * - return true if the page can now be released, false if not
+ * Release a directory folio and clean up its private state if it's not busy
+ * - return true if the folio can now be released, false if not
  */
-static int afs_dir_releasepage(struct page *page, gfp_t gfp_flags)
+static int afs_dir_releasepage(struct page *subpage, gfp_t gfp_flags)
 {
-	struct afs_vnode *dvnode = AFS_FS_I(page->mapping->host);
+	struct folio *folio = page_folio(subpage);
+	struct afs_vnode *dvnode = AFS_FS_I(folio_inode(folio));
 
-	_enter("{{%llx:%llu}[%lu]}", dvnode->fid.vid, dvnode->fid.vnode, page->index);
+	_enter("{{%llx:%llu}[%lu]}", dvnode->fid.vid, dvnode->fid.vnode, folio_index(folio));
 
-	detach_page_private(page);
+	folio_detach_private(folio);
 
 	/* The directory will need reloading. */
 	if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
 		afs_stat_v(dvnode, n_relpg);
-	return 1;
+	return true;
 }
 
 /*
- * invalidate part or all of a page
- * - release a page and clean up its private data if offset is 0 (indicating
- *   the entire page)
+ * Invalidate part or all of a folio.
  */
-static void afs_dir_invalidatepage(struct page *page, unsigned int offset,
+static void afs_dir_invalidatepage(struct page *subpage, unsigned int offset,
 				   unsigned int length)
 {
-	struct afs_vnode *dvnode = AFS_FS_I(page->mapping->host);
+	struct folio *folio = page_folio(subpage);
+	struct afs_vnode *dvnode = AFS_FS_I(folio_inode(folio));
 
-	_enter("{%lu},%u,%u", page->index, offset, length);
+	_enter("{%lu},%u,%u", folio_index(folio), offset, length);
 
-	BUG_ON(!PageLocked(page));
+	BUG_ON(!folio_test_locked(folio));
 
 	/* The directory will need reloading. */
 	if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
 		afs_stat_v(dvnode, n_inval);
 
-	/* we clean up only if the entire page is being invalidated */
-	if (offset == 0 && length == thp_size(page))
-		detach_page_private(page);
+	/* we clean up only if the entire folio is being invalidated */
+	if (offset == 0 && length == folio_size(folio))
+		folio_detach_private(folio);
 }