1 files changed, 226 insertions, 68 deletions

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 405ebd609b87..8beecbcd9679 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -1,6 +1,6 @@
 /* dir.c: AFS filesystem directory handling
  *
- * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
+ * Copyright (C) 2002, 2018 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
  *
  * This program is free software; you can redistribute it and/or
@@ -13,8 +13,10 @@
 #include <linux/fs.h>
 #include <linux/namei.h>
 #include <linux/pagemap.h>
+#include <linux/swap.h>
 #include <linux/ctype.h>
 #include <linux/sched.h>
+#include <linux/task_io_accounting_ops.h>
 #include "internal.h"
 
 static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
@@ -39,6 +41,14 @@ static int afs_symlink(struct inode *dir, struct dentry *dentry,
 static int afs_rename(struct inode *old_dir, struct dentry *old_dentry,
 		      struct inode *new_dir, struct dentry *new_dentry,
 		      unsigned int flags);
+static int afs_dir_releasepage(struct page *page, gfp_t gfp_flags);
+static void afs_dir_invalidatepage(struct page *page, unsigned int offset,
+				   unsigned int length);
+
+static int afs_dir_set_page_dirty(struct page *page)
+{
+	BUG(); /* This should never happen. */
+}
 
 const struct file_operations afs_dir_file_operations = {
 	.open		= afs_dir_open,
@@ -63,6 +73,12 @@ const struct inode_operations afs_dir_inode_operations = {
 	.listxattr	= afs_listxattr,
 };
 
+const struct address_space_operations afs_dir_aops = {
+	.set_page_dirty	= afs_dir_set_page_dirty,
+	.releasepage	= afs_dir_releasepage,
+	.invalidatepage	= afs_dir_invalidatepage,
+};
+
 const struct dentry_operations afs_fs_dentry_operations = {
 	.d_revalidate	= afs_d_revalidate,
 	.d_delete	= afs_d_delete,
@@ -140,32 +156,17 @@ struct afs_lookup_cookie {
 /*
  * check that a directory page is valid
  */
-bool afs_dir_check_page(struct inode *dir, struct page *page)
+static bool afs_dir_check_page(struct afs_vnode *dvnode, struct page *page,
+			       loff_t i_size)
 {
 	struct afs_dir_page *dbuf;
-	struct afs_vnode *vnode = AFS_FS_I(dir);
-	loff_t latter, i_size, off;
+	loff_t latter, off;
 	int tmp, qty;
 
-#if 0
-	/* check the page count */
-	qty = desc.size / sizeof(dbuf->blocks[0]);
-	if (qty == 0)
-		goto error;
-
-	if (page->index == 0 && qty != ntohs(dbuf->blocks[0].pagehdr.npages)) {
-		printk("kAFS: %s(%lu): wrong number of dir blocks %d!=%hu\n",
-		       __func__, dir->i_ino, qty,
-		       ntohs(dbuf->blocks[0].pagehdr.npages));
-		goto error;
-	}
-#endif
-
 	/* Determine how many magic numbers there should be in this page, but
 	 * we must take care because the directory may change size under us.
 	 */
 	off = page_offset(page);
-	i_size = i_size_read(dir);
 	if (i_size <= off)
 		goto checked;
 
@@ -181,60 +182,22 @@ bool afs_dir_check_page(struct inode *dir, struct page *page)
 	for (tmp = 0; tmp < qty; tmp++) {
 		if (dbuf->blocks[tmp].pagehdr.magic != AFS_DIR_MAGIC) {
 			printk("kAFS: %s(%lx): bad magic %d/%d is %04hx\n",
-			       __func__, dir->i_ino, tmp, qty,
+			       __func__, dvnode->vfs_inode.i_ino, tmp, qty,
 			       ntohs(dbuf->blocks[tmp].pagehdr.magic));
-			trace_afs_dir_check_failed(vnode, off, i_size);
+			trace_afs_dir_check_failed(dvnode, off, i_size);
 			goto error;
 		}
 	}
 
 checked:
-	afs_stat_v(vnode, n_read_dir);
-	SetPageChecked(page);
+	afs_stat_v(dvnode, n_read_dir);
 	return true;
 
 error:
-	SetPageError(page);
 	return false;
 }
 
 /*
- * discard a page cached in the pagecache
- */
-static inline void afs_dir_put_page(struct page *page)
-{
-	kunmap(page);
-	unlock_page(page);
-	put_page(page);
-}
-
-/*
- * get a page into the pagecache
- */
-static struct page *afs_dir_get_page(struct inode *dir, unsigned long index,
-				     struct key *key)
-{
-	struct page *page;
-	_enter("{%lu},%lu", dir->i_ino, index);
-
-	page = read_cache_page(dir->i_mapping, index, afs_page_filler, key);
-	if (!IS_ERR(page)) {
-		lock_page(page);
-		kmap(page);
-		if (unlikely(!PageChecked(page))) {
-			if (PageError(page))
-				goto fail;
-		}
-	}
-	return page;
-
-fail:
-	afs_dir_put_page(page);
-	_leave(" = -EIO");
-	return ERR_PTR(-EIO);
-}
-
-/*
  * open an AFS directory file
  */
 static int afs_dir_open(struct inode *inode, struct file *file)
@@ -251,6 +214,147 @@ 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
+ * get reclaimed during the iteration.
+ */
+static struct afs_read *afs_read_dir(struct afs_vnode *dvnode, struct key *key)
+{
+	struct afs_read *req;
+	loff_t i_size;
+	int nr_pages, nr_inline, i, n;
+	int ret = -ENOMEM;
+
+retry:
+	i_size = i_size_read(&dvnode->vfs_inode);
+	if (i_size < 2048)
+		return ERR_PTR(-EIO);
+	if (i_size > 2048 * 1024)
+		return ERR_PTR(-EFBIG);
+
+	_enter("%llu", i_size);
+
+	/* Get a request record to hold the page list.  We want to hold it
+	 * inline if we can, but we don't want to make an order 1 allocation.
+	 */
+	nr_pages = (i_size + PAGE_SIZE - 1) / PAGE_SIZE;
+	nr_inline = nr_pages;
+	if (nr_inline > (PAGE_SIZE - sizeof(*req)) / sizeof(struct page *))
+		nr_inline = 0;
+
+	req = kzalloc(sizeof(*req) + sizeof(struct page *) * nr_inline,
+		      GFP_KERNEL);
+	if (!req)
+		return ERR_PTR(-ENOMEM);
+
+	refcount_set(&req->usage, 1);
+	req->nr_pages = nr_pages;
+	req->actual_len = i_size; /* May change */
+	req->len = nr_pages * PAGE_SIZE; /* We can ask for more than there is */
+	req->data_version = dvnode->status.data_version; /* May change */
+	if (nr_inline > 0) {
+		req->pages = req->array;
+	} else {
+		req->pages = kcalloc(nr_pages, sizeof(struct page *),
+				     GFP_KERNEL);
+		if (!req->pages)
+			goto error;
+	}
+
+	/* Get a list of all the pages that hold or will hold the directory
+	 * content.  We need to fill in any gaps that we might find where the
+	 * memory reclaimer has been at work.  If there are any gaps, we will
+	 * need to reread the entire directory contents.
+	 */
+	i = 0;
+	do {
+		n = find_get_pages_contig(dvnode->vfs_inode.i_mapping, i,
+					  req->nr_pages - i,
+					  req->pages + i);
+		_debug("find %u at %u/%u", n, i, req->nr_pages);
+		if (n == 0) {
+			gfp_t gfp = dvnode->vfs_inode.i_mapping->gfp_mask;
+
+			if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
+				afs_stat_v(dvnode, n_inval);
+
+			ret = -ENOMEM;
+			req->pages[i] = __page_cache_alloc(gfp);
+			if (!req->pages[i])
+				goto error;
+			ret = add_to_page_cache_lru(req->pages[i],
+						    dvnode->vfs_inode.i_mapping,
+						    i, gfp);
+			if (ret < 0)
+				goto error;
+
+			set_page_private(req->pages[i], 1);
+			SetPagePrivate(req->pages[i]);
+			unlock_page(req->pages[i]);
+			i++;
+		} else {
+			i += n;
+		}
+	} while (i < req->nr_pages);
+
+	/* If we're going to reload, we need to lock all the pages to prevent
+	 * races.
+	 */
+	if (!test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags)) {
+		ret = -ERESTARTSYS;
+		for (i = 0; i < req->nr_pages; i++)
+			if (lock_page_killable(req->pages[i]) < 0)
+				goto error_unlock;
+
+		if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
+			goto success;
+
+		ret = afs_fetch_data(dvnode, key, req);
+		if (ret < 0)
+			goto error_unlock_all;
+
+		task_io_account_read(PAGE_SIZE * req->nr_pages);
+
+		if (req->len < req->file_size)
+			goto content_has_grown;
+
+		/* Validate the data we just read. */
+		ret = -EIO;
+		for (i = 0; i < req->nr_pages; i++)
+			if (!afs_dir_check_page(dvnode, req->pages[i],
+						req->actual_len))
+				goto error_unlock_all;
+
+		// TODO: Trim excess pages
+
+		set_bit(AFS_VNODE_DIR_VALID, &dvnode->flags);
+	}
+
+success:
+	i = req->nr_pages;
+	while (i > 0)
+		unlock_page(req->pages[--i]);
+	return req;
+
+error_unlock_all:
+	i = req->nr_pages;
+error_unlock:
+	while (i > 0)
+		unlock_page(req->pages[--i]);
+error:
+	afs_put_read(req);
+	_leave(" = %d", ret);
+	return ERR_PTR(ret);
+
+content_has_grown:
+	i = req->nr_pages;
+	while (i > 0)
+		unlock_page(req->pages[--i]);
+	afs_put_read(req);
+	goto retry;
+}
+
+/*
  * deal with one block in an AFS directory
  */
 static int afs_dir_iterate_block(struct dir_context *ctx,
@@ -347,8 +451,10 @@ static int afs_dir_iterate_block(struct dir_context *ctx,
 static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
 			   struct key *key)
 {
+	struct afs_vnode *dvnode = AFS_FS_I(dir);
 	union afs_dir_block *dblock;
 	struct afs_dir_page *dbuf;
+	struct afs_read *req;
 	struct page *page;
 	unsigned blkoff, limit;
 	int ret;
@@ -360,25 +466,32 @@ static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
 		return -ESTALE;
 	}
 
+	req = afs_read_dir(dvnode, key);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
 	/* round the file position up to the next entry boundary */
 	ctx->pos += sizeof(union afs_dirent) - 1;
 	ctx->pos &= ~(sizeof(union afs_dirent) - 1);
 
 	/* walk through the blocks in sequence */
 	ret = 0;
-	while (ctx->pos < dir->i_size) {
+	while (ctx->pos < req->actual_len) {
 		blkoff = ctx->pos & ~(sizeof(union afs_dir_block) - 1);
 
-		/* fetch the appropriate page from the directory */
-		page = afs_dir_get_page(dir, blkoff / PAGE_SIZE, key);
-		if (IS_ERR(page)) {
-			ret = PTR_ERR(page);
+		/* Fetch the appropriate page from the directory and re-add it
+		 * to the LRU.
+		 */
+		page = req->pages[blkoff / PAGE_SIZE];
+		if (!page) {
+			ret = -EIO;
 			break;
 		}
+		mark_page_accessed(page);
 
 		limit = blkoff & ~(PAGE_SIZE - 1);
 
-		dbuf = page_address(page);
+		dbuf = kmap(page);
 
 		/* deal with the individual blocks stashed on this page */
 		do {
@@ -386,7 +499,7 @@ static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
 					       sizeof(union afs_dir_block)];
 			ret = afs_dir_iterate_block(ctx, dblock, blkoff);
 			if (ret != 1) {
-				afs_dir_put_page(page);
+				kunmap(page);
 				goto out;
 			}
 
@@ -394,11 +507,12 @@ static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
 
 		} while (ctx->pos < dir->i_size && blkoff < limit);
 
-		afs_dir_put_page(page);
+		kunmap(page);
 		ret = 0;
 	}
 
 out:
+	afs_put_read(req);
 	_leave(" = %d", ret);
 	return ret;
 }
@@ -1491,3 +1605,47 @@ error:
 	_leave(" = %d", ret);
 	return ret;
 }
+
+/*
+ * 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
+ */
+static int afs_dir_releasepage(struct page *page, gfp_t gfp_flags)
+{
+	struct afs_vnode *dvnode = AFS_FS_I(page->mapping->host);
+
+	_enter("{{%x:%u}[%lu]}", dvnode->fid.vid, dvnode->fid.vnode, page->index);
+
+	set_page_private(page, 0);
+	ClearPagePrivate(page);
+
+	/* The directory will need reloading. */
+	if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
+		afs_stat_v(dvnode, n_relpg);
+	return 1;
+}
+
+/*
+ * invalidate part or all of a page
+ * - release a page and clean up its private data if offset is 0 (indicating
+ *   the entire page)
+ */
+static void afs_dir_invalidatepage(struct page *page, unsigned int offset,
+				   unsigned int length)
+{
+	struct afs_vnode *dvnode = AFS_FS_I(page->mapping->host);
+
+	_enter("{%lu},%u,%u", page->index, offset, length);
+
+	BUG_ON(!PageLocked(page));
+
+	/* 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 == PAGE_SIZE) {
+		set_page_private(page, 0);
+		ClearPagePrivate(page);
+	}
+}