[PATCH v7 01/16] cifs: Use alternative invalidation to using launder_folio

[David Howells <dhowells@redhat.com>]

Use writepages-based flushing invalidation instead of
invalidate_inode_pages2() and ->launder_folio().  This will allow
->launder_folio() to be removed eventually.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
---
 fs/smb/client/cifsfs.h |   1 -
 fs/smb/client/file.c   | 122 -----------------------------------------
 fs/smb/client/inode.c  |  25 ++-------
 3 files changed, 5 insertions(+), 143 deletions(-)

diff --git a/fs/smb/client/cifsfs.h b/fs/smb/client/cifsfs.h
index ca55d01117c8..1ab7e5998c58 100644
--- a/fs/smb/client/cifsfs.h
+++ b/fs/smb/client/cifsfs.h
@@ -69,7 +69,6 @@ extern int cifs_revalidate_file_attr(struct file *filp);
 extern int cifs_revalidate_dentry_attr(struct dentry *);
 extern int cifs_revalidate_file(struct file *filp);
 extern int cifs_revalidate_dentry(struct dentry *);
-extern int cifs_invalidate_mapping(struct inode *inode);
 extern int cifs_revalidate_mapping(struct inode *inode);
 extern int cifs_zap_mapping(struct inode *inode);
 extern int cifs_getattr(struct mnt_idmap *, const struct path *,
diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c
index b39caae652f6..2d5488a67965 100644
--- a/fs/smb/client/file.c
+++ b/fs/smb/client/file.c
@@ -2655,64 +2655,6 @@ struct cifs_writedata *cifs_writedata_alloc(work_func_t complete)
 	return wdata;
 }
 
-static int cifs_partialpagewrite(struct page *page, unsigned from, unsigned to)
-{
-	struct address_space *mapping = page->mapping;
-	loff_t offset = (loff_t)page->index << PAGE_SHIFT;
-	char *write_data;
-	int rc = -EFAULT;
-	int bytes_written = 0;
-	struct inode *inode;
-	struct cifsFileInfo *open_file;
-
-	if (!mapping || !mapping->host)
-		return -EFAULT;
-
-	inode = page->mapping->host;
-
-	offset += (loff_t)from;
-	write_data = kmap(page);
-	write_data += from;
-
-	if ((to > PAGE_SIZE) || (from > to)) {
-		kunmap(page);
-		return -EIO;
-	}
-
-	/* racing with truncate? */
-	if (offset > mapping->host->i_size) {
-		kunmap(page);
-		return 0; /* don't care */
-	}
-
-	/* check to make sure that we are not extending the file */
-	if (mapping->host->i_size - offset < (loff_t)to)
-		to = (unsigned)(mapping->host->i_size - offset);
-
-	rc = cifs_get_writable_file(CIFS_I(mapping->host), FIND_WR_ANY,
-				    &open_file);
-	if (!rc) {
-		bytes_written = cifs_write(open_file, open_file->pid,
-					   write_data, to - from, &offset);
-		cifsFileInfo_put(open_file);
-		/* Does mm or vfs already set times? */
-		simple_inode_init_ts(inode);
-		if ((bytes_written > 0) && (offset))
-			rc = 0;
-		else if (bytes_written < 0)
-			rc = bytes_written;
-		else
-			rc = -EFAULT;
-	} else {
-		cifs_dbg(FYI, "No writable handle for write page rc=%d\n", rc);
-		if (!is_retryable_error(rc))
-			rc = -EIO;
-	}
-
-	kunmap(page);
-	return rc;
-}
-
 /*
  * Extend the region to be written back to include subsequent contiguously
  * dirty pages if possible, but don't sleep while doing so.
@@ -3126,47 +3068,6 @@ static int cifs_writepages(struct address_space *mapping,
 	return ret;
 }
 
-static int
-cifs_writepage_locked(struct page *page, struct writeback_control *wbc)
-{
-	int rc;
-	unsigned int xid;
-
-	xid = get_xid();
-/* BB add check for wbc flags */
-	get_page(page);
-	if (!PageUptodate(page))
-		cifs_dbg(FYI, "ppw - page not up to date\n");
-
-	/*
-	 * Set the "writeback" flag, and clear "dirty" in the radix tree.
-	 *
-	 * A writepage() implementation always needs to do either this,
-	 * or re-dirty the page with "redirty_page_for_writepage()" in
-	 * the case of a failure.
-	 *
-	 * Just unlocking the page will cause the radix tree tag-bits
-	 * to fail to update with the state of the page correctly.
-	 */
-	set_page_writeback(page);
-retry_write:
-	rc = cifs_partialpagewrite(page, 0, PAGE_SIZE);
-	if (is_retryable_error(rc)) {
-		if (wbc->sync_mode == WB_SYNC_ALL && rc == -EAGAIN)
-			goto retry_write;
-		redirty_page_for_writepage(wbc, page);
-	} else if (rc != 0) {
-		SetPageError(page);
-		mapping_set_error(page->mapping, rc);
-	} else {
-		SetPageUptodate(page);
-	}
-	end_page_writeback(page);
-	put_page(page);
-	free_xid(xid);
-	return rc;
-}
-
 static int cifs_write_end(struct file *file, struct address_space *mapping,
 			loff_t pos, unsigned len, unsigned copied,
 			struct page *page, void *fsdata)
@@ -4992,27 +4893,6 @@ static void cifs_invalidate_folio(struct folio *folio, size_t offset,
 	folio_wait_private_2(folio); /* [DEPRECATED] */
 }
 
-static int cifs_launder_folio(struct folio *folio)
-{
-	int rc = 0;
-	loff_t range_start = folio_pos(folio);
-	loff_t range_end = range_start + folio_size(folio);
-	struct writeback_control wbc = {
-		.sync_mode = WB_SYNC_ALL,
-		.nr_to_write = 0,
-		.range_start = range_start,
-		.range_end = range_end,
-	};
-
-	cifs_dbg(FYI, "Launder page: %lu\n", folio->index);
-
-	if (folio_clear_dirty_for_io(folio))
-		rc = cifs_writepage_locked(&folio->page, &wbc);
-
-	folio_wait_private_2(folio); /* [DEPRECATED] */
-	return rc;
-}
-
 void cifs_oplock_break(struct work_struct *work)
 {
 	struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,
@@ -5191,7 +5071,6 @@ const struct address_space_operations cifs_addr_ops = {
 	.release_folio = cifs_release_folio,
 	.direct_IO = cifs_direct_io,
 	.invalidate_folio = cifs_invalidate_folio,
-	.launder_folio = cifs_launder_folio,
 	.migrate_folio = filemap_migrate_folio,
 	/*
 	 * TODO: investigate and if useful we could add an is_dirty_writeback
@@ -5214,6 +5093,5 @@ const struct address_space_operations cifs_addr_ops_smallbuf = {
 	.dirty_folio = netfs_dirty_folio,
 	.release_folio = cifs_release_folio,
 	.invalidate_folio = cifs_invalidate_folio,
-	.launder_folio = cifs_launder_folio,
 	.migrate_folio = filemap_migrate_folio,
 };
diff --git a/fs/smb/client/inode.c b/fs/smb/client/inode.c
index 60afab5c83d4..033948d34c5a 100644
--- a/fs/smb/client/inode.c
+++ b/fs/smb/client/inode.c
@@ -2431,24 +2431,6 @@ cifs_dentry_needs_reval(struct dentry *dentry)
 	return false;
 }
 
-/*
- * Zap the cache. Called when invalid_mapping flag is set.
- */
-int
-cifs_invalidate_mapping(struct inode *inode)
-{
-	int rc = 0;
-
-	if (inode->i_mapping && inode->i_mapping->nrpages != 0) {
-		rc = invalidate_inode_pages2(inode->i_mapping);
-		if (rc)
-			cifs_dbg(VFS, "%s: invalidate inode %p failed with rc %d\n",
-				 __func__, inode, rc);
-	}
-
-	return rc;
-}
-
 /**
  * cifs_wait_bit_killable - helper for functions that are sleeping on bit locks
  *
@@ -2485,9 +2467,12 @@ cifs_revalidate_mapping(struct inode *inode)
 		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RW_CACHE)
 			goto skip_invalidate;
 
-		rc = cifs_invalidate_mapping(inode);
-		if (rc)
+		rc = filemap_invalidate_inode(inode, true, 0, LLONG_MAX);
+		if (rc) {
+			cifs_dbg(VFS, "%s: invalidate inode %p failed with rc %d\n",
+				 __func__, inode, rc);
 			set_bit(CIFS_INO_INVALID_MAPPING, flags);
+		}
 	}
 
 skip_invalidate: