1 files changed, 180 insertions, 156 deletions

diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index cce9ace651a2..47b9a1122f34 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -1,7 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- *  linux/fs/9p/vfs_addr.c
- *
  * This file contians vfs address (mmap) ops for 9P2000.
  *
  *  Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
@@ -18,8 +16,9 @@
 #include <linux/pagemap.h>
 #include <linux/idr.h>
 #include <linux/sched.h>
+#include <linux/swap.h>
 #include <linux/uio.h>
-#include <linux/bvec.h>
+#include <linux/netfs.h>
 #include <net/9p/9p.h>
 #include <net/9p/client.h>
 
@@ -29,196 +28,213 @@
 #include "fid.h"
 
 /**
- * v9fs_fid_readpage - read an entire page in from 9P
- *
- * @fid: fid being read
- * @page: structure to page
- *
+ * v9fs_issue_read - Issue a read from 9P
+ * @subreq: The read to make
  */
-static int v9fs_fid_readpage(void *data, struct page *page)
+static void v9fs_issue_read(struct netfs_io_subrequest *subreq)
 {
-	struct p9_fid *fid = data;
-	struct inode *inode = page->mapping->host;
-	struct bio_vec bvec = {.bv_page = page, .bv_len = PAGE_SIZE};
+	struct netfs_io_request *rreq = subreq->rreq;
+	struct p9_fid *fid = rreq->netfs_priv;
 	struct iov_iter to;
-	int retval, err;
+	loff_t pos = subreq->start + subreq->transferred;
+	size_t len = subreq->len   - subreq->transferred;
+	int total, err;
 
-	p9_debug(P9_DEBUG_VFS, "\n");
+	iov_iter_xarray(&to, READ, &rreq->mapping->i_pages, pos, len);
 
-	BUG_ON(!PageLocked(page));
+	total = p9_client_read(fid, pos, &to, &err);
 
-	retval = v9fs_readpage_from_fscache(inode, page);
-	if (retval == 0)
-		return retval;
+	/* if we just extended the file size, any portion not in
+	 * cache won't be on server and is zeroes */
+	__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
 
-	iov_iter_bvec(&to, READ, &bvec, 1, PAGE_SIZE);
+	netfs_subreq_terminated(subreq, err ?: total, false);
+}
 
-	retval = p9_client_read(fid, page_offset(page), &to, &err);
-	if (err) {
-		v9fs_uncache_page(inode, page);
-		retval = err;
-		goto done;
-	}
+/**
+ * v9fs_init_request - Initialise a read request
+ * @rreq: The read request
+ * @file: The file being read from
+ */
+static int v9fs_init_request(struct netfs_io_request *rreq, struct file *file)
+{
+	struct inode *inode = file_inode(file);
+	struct v9fs_inode *v9inode = V9FS_I(inode);
+	struct p9_fid *fid = file->private_data;
 
-	zero_user(page, retval, PAGE_SIZE - retval);
-	flush_dcache_page(page);
-	SetPageUptodate(page);
+	BUG_ON(!fid);
 
-	v9fs_readpage_to_fscache(inode, page);
-	retval = 0;
+	/* we might need to read from a fid that was opened write-only
+	 * for read-modify-write of page cache, use the writeback fid
+	 * for that */
+	if (rreq->origin == NETFS_READ_FOR_WRITE &&
+			(fid->mode & O_ACCMODE) == O_WRONLY) {
+		fid = v9inode->writeback_fid;
+		BUG_ON(!fid);
+	}
 
-done:
-	unlock_page(page);
-	return retval;
+	p9_fid_get(fid);
+	rreq->netfs_priv = fid;
+	return 0;
 }
 
 /**
- * v9fs_vfs_readpage - read an entire page in from 9P
- *
- * @filp: file being read
- * @page: structure to page
- *
+ * v9fs_free_request - Cleanup request initialized by v9fs_init_rreq
+ * @rreq: The I/O request to clean up
  */
-
-static int v9fs_vfs_readpage(struct file *filp, struct page *page)
+static void v9fs_free_request(struct netfs_io_request *rreq)
 {
-	return v9fs_fid_readpage(filp->private_data, page);
+	struct p9_fid *fid = rreq->netfs_priv;
+
+	p9_fid_put(fid);
 }
 
 /**
- * v9fs_vfs_readpages - read a set of pages from 9P
- *
- * @filp: file being read
- * @mapping: the address space
- * @pages: list of pages to read
- * @nr_pages: count of pages to read
- *
+ * v9fs_begin_cache_operation - Begin a cache operation for a read
+ * @rreq: The read request
  */
-
-static int v9fs_vfs_readpages(struct file *filp, struct address_space *mapping,
-			     struct list_head *pages, unsigned nr_pages)
+static int v9fs_begin_cache_operation(struct netfs_io_request *rreq)
 {
-	int ret = 0;
-	struct inode *inode;
-
-	inode = mapping->host;
-	p9_debug(P9_DEBUG_VFS, "inode: %p file: %p\n", inode, filp);
-
-	ret = v9fs_readpages_from_fscache(inode, mapping, pages, &nr_pages);
-	if (ret == 0)
-		return ret;
+#ifdef CONFIG_9P_FSCACHE
+	struct fscache_cookie *cookie = v9fs_inode_cookie(V9FS_I(rreq->inode));
 
-	ret = read_cache_pages(mapping, pages, v9fs_fid_readpage,
-			filp->private_data);
-	p9_debug(P9_DEBUG_VFS, "  = %d\n", ret);
-	return ret;
+	return fscache_begin_read_operation(&rreq->cache_resources, cookie);
+#else
+	return -ENOBUFS;
+#endif
 }
 
+const struct netfs_request_ops v9fs_req_ops = {
+	.init_request		= v9fs_init_request,
+	.free_request		= v9fs_free_request,
+	.begin_cache_operation	= v9fs_begin_cache_operation,
+	.issue_read		= v9fs_issue_read,
+};
+
 /**
- * v9fs_release_page - release the private state associated with a page
+ * v9fs_release_folio - release the private state associated with a folio
+ * @folio: The folio to be released
+ * @gfp: The caller's allocation restrictions
  *
- * Returns 1 if the page can be released, false otherwise.
+ * Returns true if the page can be released, false otherwise.
  */
 
-static int v9fs_release_page(struct page *page, gfp_t gfp)
+static bool v9fs_release_folio(struct folio *folio, gfp_t gfp)
 {
-	if (PagePrivate(page))
-		return 0;
-	return v9fs_fscache_release_page(page, gfp);
+	struct inode *inode = folio_inode(folio);
+
+	if (folio_test_private(folio))
+		return false;
+#ifdef CONFIG_9P_FSCACHE
+	if (folio_test_fscache(folio)) {
+		if (current_is_kswapd() || !(gfp & __GFP_FS))
+			return false;
+		folio_wait_fscache(folio);
+	}
+#endif
+	fscache_note_page_release(v9fs_inode_cookie(V9FS_I(inode)));
+	return true;
 }
 
-/**
- * v9fs_invalidate_page - Invalidate a page completely or partially
- *
- * @page: structure to page
- * @offset: offset in the page
- */
+static void v9fs_invalidate_folio(struct folio *folio, size_t offset,
+				 size_t length)
+{
+	folio_wait_fscache(folio);
+}
 
-static void v9fs_invalidate_page(struct page *page, unsigned int offset,
-				 unsigned int length)
+static void v9fs_write_to_cache_done(void *priv, ssize_t transferred_or_error,
+				     bool was_async)
 {
-	/*
-	 * If called with zero offset, we should release
-	 * the private state assocated with the page
-	 */
-	if (offset == 0 && length == PAGE_SIZE)
-		v9fs_fscache_invalidate_page(page);
+	struct v9fs_inode *v9inode = priv;
+	__le32 version;
+
+	if (IS_ERR_VALUE(transferred_or_error) &&
+	    transferred_or_error != -ENOBUFS) {
+		version = cpu_to_le32(v9inode->qid.version);
+		fscache_invalidate(v9fs_inode_cookie(v9inode), &version,
+				   i_size_read(&v9inode->netfs.inode), 0);
+	}
 }
 
-static int v9fs_vfs_writepage_locked(struct page *page)
+static int v9fs_vfs_write_folio_locked(struct folio *folio)
 {
-	struct inode *inode = page->mapping->host;
+	struct inode *inode = folio_inode(folio);
 	struct v9fs_inode *v9inode = V9FS_I(inode);
-	loff_t size = i_size_read(inode);
+	struct fscache_cookie *cookie = v9fs_inode_cookie(v9inode);
+	loff_t start = folio_pos(folio);
+	loff_t i_size = i_size_read(inode);
 	struct iov_iter from;
-	struct bio_vec bvec;
-	int err, len;
+	size_t len = folio_size(folio);
+	int err;
 
-	if (page->index == size >> PAGE_SHIFT)
-		len = size & ~PAGE_MASK;
-	else
-		len = PAGE_SIZE;
+	if (start >= i_size)
+		return 0; /* Simultaneous truncation occurred */
 
-	bvec.bv_page = page;
-	bvec.bv_offset = 0;
-	bvec.bv_len = len;
-	iov_iter_bvec(&from, WRITE, &bvec, 1, len);
+	len = min_t(loff_t, i_size - start, len);
+
+	iov_iter_xarray(&from, WRITE, &folio_mapping(folio)->i_pages, start, len);
 
 	/* We should have writeback_fid always set */
 	BUG_ON(!v9inode->writeback_fid);
 
-	set_page_writeback(page);
+	folio_wait_fscache(folio);
+	folio_start_writeback(folio);
+
+	p9_client_write(v9inode->writeback_fid, start, &from, &err);
 
-	p9_client_write(v9inode->writeback_fid, page_offset(page), &from, &err);
+	if (err == 0 &&
+	    fscache_cookie_enabled(cookie) &&
+	    test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags)) {
+		folio_start_fscache(folio);
+		fscache_write_to_cache(v9fs_inode_cookie(v9inode),
+				       folio_mapping(folio), start, len, i_size,
+				       v9fs_write_to_cache_done, v9inode,
+				       true);
+	}
 
-	end_page_writeback(page);
+	folio_end_writeback(folio);
 	return err;
 }
 
 static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
 {
+	struct folio *folio = page_folio(page);
 	int retval;
 
-	p9_debug(P9_DEBUG_VFS, "page %p\n", page);
+	p9_debug(P9_DEBUG_VFS, "folio %p\n", folio);
 
-	retval = v9fs_vfs_writepage_locked(page);
+	retval = v9fs_vfs_write_folio_locked(folio);
 	if (retval < 0) {
 		if (retval == -EAGAIN) {
-			redirty_page_for_writepage(wbc, page);
+			folio_redirty_for_writepage(wbc, folio);
 			retval = 0;
 		} else {
-			SetPageError(page);
-			mapping_set_error(page->mapping, retval);
+			mapping_set_error(folio_mapping(folio), retval);
 		}
 	} else
 		retval = 0;
 
-	unlock_page(page);
+	folio_unlock(folio);
 	return retval;
 }
 
-/**
- * v9fs_launder_page - Writeback a dirty page
- * Returns 0 on success.
- */
-
-static int v9fs_launder_page(struct page *page)
+static int v9fs_launder_folio(struct folio *folio)
 {
 	int retval;
-	struct inode *inode = page->mapping->host;
 
-	v9fs_fscache_wait_on_page_write(inode, page);
-	if (clear_page_dirty_for_io(page)) {
-		retval = v9fs_vfs_writepage_locked(page);
+	if (folio_clear_dirty_for_io(folio)) {
+		retval = v9fs_vfs_write_folio_locked(folio);
 		if (retval)
 			return retval;
 	}
+	folio_wait_fscache(folio);
 	return 0;
 }
 
 /**
  * v9fs_direct_IO - 9P address space operation for direct I/O
  * @iocb: target I/O control block
+ * @iter: The data/buffer to use
  *
  * The presence of v9fs_direct_IO() in the address space ops vector
  * allowes open() O_DIRECT flags which would have failed otherwise.
@@ -238,11 +254,13 @@ v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 	loff_t pos = iocb->ki_pos;
 	ssize_t n;
 	int err = 0;
+
 	if (iov_iter_rw(iter) == WRITE) {
 		n = p9_client_write(file->private_data, pos, iter, &err);
 		if (n) {
 			struct inode *inode = file_inode(file);
 			loff_t i_size = i_size_read(inode);
+
 			if (pos + n > i_size)
 				inode_add_bytes(inode, pos + n - i_size);
 		}
@@ -253,58 +271,49 @@ v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 }
 
 static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
-			    loff_t pos, unsigned len, unsigned flags,
-			    struct page **pagep, void **fsdata)
+			    loff_t pos, unsigned int len,
+			    struct page **subpagep, void **fsdata)
 {
-	int retval = 0;
-	struct page *page;
-	struct v9fs_inode *v9inode;
-	pgoff_t index = pos >> PAGE_SHIFT;
-	struct inode *inode = mapping->host;
-
+	int retval;
+	struct folio *folio;
+	struct v9fs_inode *v9inode = V9FS_I(mapping->host);
 
 	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
 
-	v9inode = V9FS_I(inode);
-start:
-	page = grab_cache_page_write_begin(mapping, index, flags);
-	if (!page) {
-		retval = -ENOMEM;
-		goto out;
-	}
 	BUG_ON(!v9inode->writeback_fid);
-	if (PageUptodate(page))
-		goto out;
 
-	if (len == PAGE_SIZE)
-		goto out;
+	/* Prefetch area to be written into the cache if we're caching this
+	 * file.  We need to do this before we get a lock on the page in case
+	 * there's more than one writer competing for the same cache block.
+	 */
+	retval = netfs_write_begin(&v9inode->netfs, filp, mapping, pos, len, &folio, fsdata);
+	if (retval < 0)
+		return retval;
 
-	retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
-	put_page(page);
-	if (!retval)
-		goto start;
-out:
-	*pagep = page;
+	*subpagep = &folio->page;
 	return retval;
 }
 
 static int v9fs_write_end(struct file *filp, struct address_space *mapping,
-			  loff_t pos, unsigned len, unsigned copied,
-			  struct page *page, void *fsdata)
+			  loff_t pos, unsigned int len, unsigned int copied,
+			  struct page *subpage, void *fsdata)
 {
 	loff_t last_pos = pos + copied;
-	struct inode *inode = page->mapping->host;
+	struct folio *folio = page_folio(subpage);
+	struct inode *inode = mapping->host;
+	struct v9fs_inode *v9inode = V9FS_I(inode);
 
 	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
 
-	if (!PageUptodate(page)) {
+	if (!folio_test_uptodate(folio)) {
 		if (unlikely(copied < len)) {
 			copied = 0;
 			goto out;
-		} else if (len == PAGE_SIZE) {
-			SetPageUptodate(page);
 		}
+
+		folio_mark_uptodate(folio);
 	}
+
 	/*
 	 * No need to use i_size_read() here, the i_size
 	 * cannot change under us because we hold the i_mutex.
@@ -312,25 +321,40 @@ static int v9fs_write_end(struct file *filp, struct address_space *mapping,
 	if (last_pos > inode->i_size) {
 		inode_add_bytes(inode, last_pos - inode->i_size);
 		i_size_write(inode, last_pos);
+		fscache_update_cookie(v9fs_inode_cookie(v9inode), NULL, &last_pos);
 	}
-	set_page_dirty(page);
+	folio_mark_dirty(folio);
 out:
-	unlock_page(page);
-	put_page(page);
+	folio_unlock(folio);
+	folio_put(folio);
 
 	return copied;
 }
 
+#ifdef CONFIG_9P_FSCACHE
+/*
+ * Mark a page as having been made dirty and thus needing writeback.  We also
+ * need to pin the cache object to write back to.
+ */
+static bool v9fs_dirty_folio(struct address_space *mapping, struct folio *folio)
+{
+	struct v9fs_inode *v9inode = V9FS_I(mapping->host);
+
+	return fscache_dirty_folio(mapping, folio, v9fs_inode_cookie(v9inode));
+}
+#else
+#define v9fs_dirty_folio filemap_dirty_folio
+#endif
 
 const struct address_space_operations v9fs_addr_operations = {
-	.readpage = v9fs_vfs_readpage,
-	.readpages = v9fs_vfs_readpages,
-	.set_page_dirty = __set_page_dirty_nobuffers,
+	.read_folio = netfs_read_folio,
+	.readahead = netfs_readahead,
+	.dirty_folio = v9fs_dirty_folio,
 	.writepage = v9fs_vfs_writepage,
 	.write_begin = v9fs_write_begin,
 	.write_end = v9fs_write_end,
-	.releasepage = v9fs_release_page,
-	.invalidatepage = v9fs_invalidate_page,
-	.launder_page = v9fs_launder_page,
+	.release_folio = v9fs_release_folio,
+	.invalidate_folio = v9fs_invalidate_folio,
+	.launder_folio = v9fs_launder_folio,
 	.direct_IO = v9fs_direct_IO,
 };