1 files changed, 65 insertions, 3 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 3b942ecdd4be..75ddce8ef456 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -1169,7 +1169,8 @@ try_again:
 	rc = posix_lock_file(file, flock, NULL);
 	up_write(&cinode->lock_sem);
 	if (rc == FILE_LOCK_DEFERRED) {
-		rc = wait_event_interruptible(flock->fl_wait, !flock->fl_blocker);
+		rc = wait_event_interruptible(flock->fl_wait,
+					list_empty(&flock->fl_blocked_member));
 		if (!rc)
 			goto try_again;
 		locks_delete_block(flock);
@@ -3840,7 +3841,7 @@ again:
 	if (rc == -ENODATA)
 		rc = 0;
 
-	ctx->rc = (rc == 0) ? ctx->total_len : rc;
+	ctx->rc = (rc == 0) ? (ssize_t)ctx->total_len : rc;
 
 	mutex_unlock(&ctx->aio_mutex);
 
@@ -4059,7 +4060,7 @@ cifs_read(struct file *file, char *read_data, size_t read_size, loff_t *offset)
 			 * than it negotiated since it will refuse the read
 			 * then.
 			 */
-			if ((tcon->ses) && !(tcon->ses->capabilities &
+			if (!(tcon->ses->capabilities &
 				tcon->ses->server->vals->cap_large_files)) {
 				current_read_size = min_t(uint,
 					current_read_size, CIFSMaxBufSize);
@@ -4807,6 +4808,60 @@ cifs_direct_io(struct kiocb *iocb, struct iov_iter *iter)
         return -EINVAL;
 }
 
+static int cifs_swap_activate(struct swap_info_struct *sis,
+			      struct file *swap_file, sector_t *span)
+{
+	struct cifsFileInfo *cfile = swap_file->private_data;
+	struct inode *inode = swap_file->f_mapping->host;
+	unsigned long blocks;
+	long long isize;
+
+	cifs_dbg(FYI, "swap activate\n");
+
+	spin_lock(&inode->i_lock);
+	blocks = inode->i_blocks;
+	isize = inode->i_size;
+	spin_unlock(&inode->i_lock);
+	if (blocks*512 < isize) {
+		pr_warn("swap activate: swapfile has holes\n");
+		return -EINVAL;
+	}
+	*span = sis->pages;
+
+	printk_once(KERN_WARNING "Swap support over SMB3 is experimental\n");
+
+	/*
+	 * TODO: consider adding ACL (or documenting how) to prevent other
+	 * users (on this or other systems) from reading it
+	 */
+
+
+	/* TODO: add sk_set_memalloc(inet) or similar */
+
+	if (cfile)
+		cfile->swapfile = true;
+	/*
+	 * TODO: Since file already open, we can't open with DENY_ALL here
+	 * but we could add call to grab a byte range lock to prevent others
+	 * from reading or writing the file
+	 */
+
+	return 0;
+}
+
+static void cifs_swap_deactivate(struct file *file)
+{
+	struct cifsFileInfo *cfile = file->private_data;
+
+	cifs_dbg(FYI, "swap deactivate\n");
+
+	/* TODO: undo sk_set_memalloc(inet) will eventually be needed */
+
+	if (cfile)
+		cfile->swapfile = false;
+
+	/* do we need to unpin (or unlock) the file */
+}
 
 const struct address_space_operations cifs_addr_ops = {
 	.readpage = cifs_readpage,
@@ -4820,6 +4875,13 @@ const struct address_space_operations cifs_addr_ops = {
 	.direct_IO = cifs_direct_io,
 	.invalidatepage = cifs_invalidate_page,
 	.launder_page = cifs_launder_page,
+	/*
+	 * TODO: investigate and if useful we could add an cifs_migratePage
+	 * helper (under an CONFIG_MIGRATION) in the future, and also
+	 * investigate and add an is_dirty_writeback helper if needed
+	 */
+	.swap_activate = cifs_swap_activate,
+	.swap_deactivate = cifs_swap_deactivate,
 };
 
 /*