Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index ab3d5f5..fe7f0bd 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  linux/fs/9p/vfs_file.c
  *
@@ -5,22 +6,6 @@
  *
  *  Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
  *  Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
- *
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License version 2
- *  as published by the Free Software Foundation.
- *
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
- *
- *  You should have received a copy of the GNU General Public License
- *  along with this program; if not, write to:
- *  Free Software Foundation
- *  51 Franklin Street, Fifth Floor
- *  Boston, MA  02111-1301  USA
- *
  */
 
 #include <linux/module.h>
@@ -154,6 +139,7 @@
 	uint8_t status = P9_LOCK_ERROR;
 	int res = 0;
 	unsigned char fl_type;
+	struct v9fs_session_info *v9ses;
 
 	fid = filp->private_data;
 	BUG_ON(fid == NULL);
@@ -189,6 +175,8 @@
 	if (IS_SETLKW(cmd))
 		flock.flags = P9_LOCK_FLAGS_BLOCK;
 
+	v9ses = v9fs_inode2v9ses(file_inode(filp));
+
 	/*
 	 * if its a blocked request and we get P9_LOCK_BLOCKED as the status
 	 * for lock request, keep on trying
@@ -202,7 +190,8 @@
 			break;
 		if (status == P9_LOCK_BLOCKED && !IS_SETLKW(cmd))
 			break;
-		if (schedule_timeout_interruptible(P9_LOCK_TIMEOUT) != 0)
+		if (schedule_timeout_interruptible(v9ses->session_lock_timeout)
+				!= 0)
 			break;
 		/*
 		 * p9_client_lock_dotl overwrites flock.client_id with the
@@ -224,7 +213,7 @@
 		break;
 	default:
 		WARN_ONCE(1, "unknown lock status code: %d\n", status);
-		/* fallthough */
+		/* fall through */
 	case P9_LOCK_ERROR:
 	case P9_LOCK_GRACE:
 		res = -ENOLCK;
@@ -442,7 +431,11 @@
 		i_size = i_size_read(inode);
 		if (iocb->ki_pos > i_size) {
 			inode_add_bytes(inode, iocb->ki_pos - i_size);
-			i_size_write(inode, iocb->ki_pos);
+			/*
+			 * Need to serialize against i_size_write() in
+			 * v9fs_stat2inode()
+			 */
+			v9fs_i_size_write(inode, iocb->ki_pos);
 		}
 		return retval;
 	}
@@ -520,6 +513,7 @@
 	v9inode = V9FS_I(inode);
 	mutex_lock(&v9inode->v_mutex);
 	if (!v9inode->writeback_fid &&
+	    (vma->vm_flags & VM_SHARED) &&
 	    (vma->vm_flags & VM_WRITE)) {
 		/*
 		 * clone a fid and add it to writeback_fid
@@ -621,6 +615,8 @@
 			(vma->vm_end - vma->vm_start - 1),
 	};
 
+	if (!(vma->vm_flags & VM_SHARED))
+		return;
 
 	p9_debug(P9_DEBUG_VFS, "9p VMA close, %p, flushing", vma);