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

fs/afs/dir_edit.c

@@ -104,6 +104,25 @@ static void afs_clear_contig_bits(union afs_xdr_dir_block *block,
 	block->hdr.bitmap[7] &= ~(u8)(mask >> 7 * 8);
 }
 
+/*
+ * Get a new directory folio.
+ */
+static struct folio *afs_dir_get_folio(struct afs_vnode *vnode, pgoff_t index)
+{
+	struct address_space *mapping = vnode->vfs_inode.i_mapping;
+	struct folio *folio;
+
+	folio = __filemap_get_folio(mapping, index,
+				    FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
+				    mapping->gfp_mask);
+	if (!folio)
+		clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
+	else if (folio && !folio_test_private(folio))
+		folio_attach_private(folio, (void *)1);
+
+	return folio;
+}
+
 /*
  * Scan a directory block looking for a dirent of the right name.
  */
@@ -188,13 +207,11 @@ void afs_edit_dir_add(struct afs_vnode *vnode,
 		      enum afs_edit_dir_reason why)
 {
 	union afs_xdr_dir_block *meta, *block;
-	struct afs_xdr_dir_page *meta_page, *dir_page;
 	union afs_xdr_dirent *de;
-	struct page *page0, *page;
+	struct folio *folio0, *folio;
 	unsigned int need_slots, nr_blocks, b;
 	pgoff_t index;
 	loff_t i_size;
-	gfp_t gfp;
 	int slot;
 
 	_enter(",,{%d,%s},", name->len, name->name);
@@ -206,10 +223,8 @@ void afs_edit_dir_add(struct afs_vnode *vnode,
 		return;
 	}
 
-	gfp = vnode->vfs_inode.i_mapping->gfp_mask;
-	page0 = find_or_create_page(vnode->vfs_inode.i_mapping, 0, gfp);
-	if (!page0) {
-		clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
+	folio0 = afs_dir_get_folio(vnode, 0);
+	if (!folio0) {
 		_leave(" [fgp]");
 		return;
 	}
@@ -217,42 +232,35 @@ void afs_edit_dir_add(struct afs_vnode *vnode,
 	/* Work out how many slots we're going to need. */
 	need_slots = afs_dir_calc_slots(name->len);
 
-	meta_page = kmap(page0);
-	meta = &meta_page->blocks[0];
+	meta = kmap_local_folio(folio0, 0);
 	if (i_size == 0)
 		goto new_directory;
 	nr_blocks = i_size / AFS_DIR_BLOCK_SIZE;
 
-	/* Find a block that has sufficient slots available.  Each VM page
+	/* Find a block that has sufficient slots available.  Each folio
 	 * contains two or more directory blocks.
 	 */
 	for (b = 0; b < nr_blocks + 1; b++) {
-		/* If the directory extended into a new page, then we need to
-		 * tack a new page on the end.
+		/* If the directory extended into a new folio, then we need to
+		 * tack a new folio on the end.
 		 */
 		index = b / AFS_DIR_BLOCKS_PER_PAGE;
-		if (index == 0) {
-			page = page0;
-			dir_page = meta_page;
-		} else {
-			if (nr_blocks >= AFS_DIR_MAX_BLOCKS)
-				goto error;
-			gfp = vnode->vfs_inode.i_mapping->gfp_mask;
-			page = find_or_create_page(vnode->vfs_inode.i_mapping,
-						   index, gfp);
-			if (!page)
+		if (nr_blocks >= AFS_DIR_MAX_BLOCKS)
+			goto error;
+		if (index >= folio_nr_pages(folio0)) {
+			folio = afs_dir_get_folio(vnode, index);
+			if (!folio)
 				goto error;
-			if (!PagePrivate(page))
-				attach_page_private(page, (void *)1);
-			dir_page = kmap(page);
+		} else {
+			folio = folio0;
 		}
 
+		block = kmap_local_folio(folio, b * AFS_DIR_BLOCK_SIZE - folio_file_pos(folio));
+
 		/* Abandon the edit if we got a callback break. */
 		if (!test_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
 			goto invalidated;
 
-		block = &dir_page->blocks[b % AFS_DIR_BLOCKS_PER_PAGE];
-
 		_debug("block %u: %2u %3u %u",
 		       b,
 		       (b < AFS_DIR_BLOCKS_WITH_CTR) ? meta->meta.alloc_ctrs[b] : 99,
@@ -266,7 +274,7 @@ void afs_edit_dir_add(struct afs_vnode *vnode,
 			afs_set_i_size(vnode, (b + 1) * AFS_DIR_BLOCK_SIZE);
 		}
 
-		/* Only lower dir pages have a counter in the header. */
+		/* Only lower dir blocks have a counter in the header. */
 		if (b >= AFS_DIR_BLOCKS_WITH_CTR ||
 		    meta->meta.alloc_ctrs[b] >= need_slots) {
 			/* We need to try and find one or more consecutive
@@ -279,10 +287,10 @@ void afs_edit_dir_add(struct afs_vnode *vnode,
 			}
 		}
 
-		if (page != page0) {
-			unlock_page(page);
-			kunmap(page);
-			put_page(page);
+		kunmap_local(block);
+		if (folio != folio0) {
+			folio_unlock(folio);
+			folio_put(folio);
 		}
 	}
 
@@ -298,8 +306,8 @@ void afs_edit_dir_add(struct afs_vnode *vnode,
 	i_size = AFS_DIR_BLOCK_SIZE;
 	afs_set_i_size(vnode, i_size);
 	slot = AFS_DIR_RESV_BLOCKS0;
-	page = page0;
-	block = meta;
+	folio = folio0;
+	block = kmap_local_folio(folio, 0);
 	nr_blocks = 1;
 	b = 0;
 
@@ -318,10 +326,10 @@ void afs_edit_dir_add(struct afs_vnode *vnode,
 
 	/* Adjust the bitmap. */
 	afs_set_contig_bits(block, slot, need_slots);
-	if (page != page0) {
-		unlock_page(page);
-		kunmap(page);
-		put_page(page);
+	kunmap_local(block);
+	if (folio != folio0) {
+		folio_unlock(folio);
+		folio_put(folio);
 	}
 
 	/* Adjust the allocation counter. */
@@ -333,18 +341,19 @@ void afs_edit_dir_add(struct afs_vnode *vnode,
 	_debug("Insert %s in %u[%u]", name->name, b, slot);
 
 out_unmap:
-	unlock_page(page0);
-	kunmap(page0);
-	put_page(page0);
+	kunmap_local(meta);
+	folio_unlock(folio0);
+	folio_put(folio0);
 	_leave("");
 	return;
 
 invalidated:
 	trace_afs_edit_dir(vnode, why, afs_edit_dir_create_inval, 0, 0, 0, 0, name->name);
 	clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
-	if (page != page0) {
-		kunmap(page);
-		put_page(page);
+	kunmap_local(block);
+	if (folio != folio0) {
+		folio_unlock(folio);
+		folio_put(folio);
 	}
 	goto out_unmap;
 
@@ -364,10 +373,9 @@ void afs_edit_dir_add(struct afs_vnode *vnode,
 void afs_edit_dir_remove(struct afs_vnode *vnode,
 			 struct qstr *name, enum afs_edit_dir_reason why)
 {
-	struct afs_xdr_dir_page *meta_page, *dir_page;
 	union afs_xdr_dir_block *meta, *block;
 	union afs_xdr_dirent *de;
-	struct page *page0, *page;
+	struct folio *folio0, *folio;
 	unsigned int need_slots, nr_blocks, b;
 	pgoff_t index;
 	loff_t i_size;
@@ -384,9 +392,8 @@ void afs_edit_dir_remove(struct afs_vnode *vnode,
 	}
 	nr_blocks = i_size / AFS_DIR_BLOCK_SIZE;
 
-	page0 = find_lock_page(vnode->vfs_inode.i_mapping, 0);
-	if (!page0) {
-		clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
+	folio0 = afs_dir_get_folio(vnode, 0);
+	if (!folio0) {
 		_leave(" [fgp]");
 		return;
 	}
@@ -394,30 +401,27 @@ void afs_edit_dir_remove(struct afs_vnode *vnode,
 	/* Work out how many slots we're going to discard. */
 	need_slots = afs_dir_calc_slots(name->len);
 
-	meta_page = kmap(page0);
-	meta = &meta_page->blocks[0];
+	meta = kmap_local_folio(folio0, 0);
 
-	/* Find a page that has sufficient slots available.  Each VM page
+	/* Find a block that has sufficient slots available.  Each folio
 	 * contains two or more directory blocks.
 	 */
 	for (b = 0; b < nr_blocks; b++) {
 		index = b / AFS_DIR_BLOCKS_PER_PAGE;
-		if (index != 0) {
-			page = find_lock_page(vnode->vfs_inode.i_mapping, index);
-			if (!page)
+		if (index >= folio_nr_pages(folio0)) {
+			folio = afs_dir_get_folio(vnode, index);
+			if (!folio)
 				goto error;
-			dir_page = kmap(page);
 		} else {
-			page = page0;
-			dir_page = meta_page;
+			folio = folio0;
 		}
 
+		block = kmap_local_folio(folio, b * AFS_DIR_BLOCK_SIZE - folio_file_pos(folio));
+
 		/* Abandon the edit if we got a callback break. */
 		if (!test_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
 			goto invalidated;
 
-		block = &dir_page->blocks[b % AFS_DIR_BLOCKS_PER_PAGE];
-
 		if (b > AFS_DIR_BLOCKS_WITH_CTR ||
 		    meta->meta.alloc_ctrs[b] <= AFS_DIR_SLOTS_PER_BLOCK - 1 - need_slots) {
 			slot = afs_dir_scan_block(block, name, b);
@@ -425,10 +429,10 @@ void afs_edit_dir_remove(struct afs_vnode *vnode,
 				goto found_dirent;
 		}
 
-		if (page != page0) {
-			unlock_page(page);
-			kunmap(page);
-			put_page(page);
+		kunmap_local(block);
+		if (folio != folio0) {
+			folio_unlock(folio);
+			folio_put(folio);
 		}
 	}
 
@@ -449,10 +453,10 @@ void afs_edit_dir_remove(struct afs_vnode *vnode,
 
 	/* Adjust the bitmap. */
 	afs_clear_contig_bits(block, slot, need_slots);
-	if (page != page0) {
-		unlock_page(page);
-		kunmap(page);
-		put_page(page);
+	kunmap_local(block);
+	if (folio != folio0) {
+		folio_unlock(folio);
+		folio_put(folio);
 	}
 
 	/* Adjust the allocation counter. */
@@ -464,9 +468,9 @@ void afs_edit_dir_remove(struct afs_vnode *vnode,
 	_debug("Remove %s from %u[%u]", name->name, b, slot);
 
 out_unmap:
-	unlock_page(page0);
-	kunmap(page0);
-	put_page(page0);
+	kunmap_local(meta);
+	folio_unlock(folio0);
+	folio_put(folio0);
 	_leave("");
 	return;
 
@@ -474,10 +478,10 @@ void afs_edit_dir_remove(struct afs_vnode *vnode,
 	trace_afs_edit_dir(vnode, why, afs_edit_dir_delete_inval,
 			   0, 0, 0, 0, name->name);
 	clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
-	if (page != page0) {
-		unlock_page(page);
-		kunmap(page);
-		put_page(page);
+	kunmap_local(block);
+	if (folio != folio0) {
+		folio_unlock(folio);
+		folio_put(folio);
 	}
 	goto out_unmap;