From: David Howells <dhowells@redhat.com>
Date: Fri, 12 Jun 2020 22:58:51 +0000 (+0100)
Subject: afs: afs_write_end() should change i_size under the right lock
X-Git-Tag: v5.4.49~46
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=c8c19fcdabdbcc923564cc9258b01db3c0e0ed22;p=platform%2Fkernel%2Flinux-rpi.git

afs: afs_write_end() should change i_size under the right lock

[ Upstream commit 1f32ef79897052ef7d3d154610d8d6af95abde83 ]

Fix afs_write_end() to change i_size under vnode->cb_lock rather than
->wb_lock so that it doesn't race with afs_vnode_commit_status() and
afs_getattr().

The ->wb_lock is only meant to guard access to ->wb_keys which isn't
accessed by that piece of code.

Fixes: 4343d00872e1 ("afs: Get rid of the afs_writeback record")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/fs/afs/write.c b/fs/afs/write.c
index 371db86..96b042a 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -194,11 +194,11 @@ int afs_write_end(struct file *file, struct address_space *mapping,
 
 	i_size = i_size_read(&vnode->vfs_inode);
 	if (maybe_i_size > i_size) {
-		spin_lock(&vnode->wb_lock);
+		write_seqlock(&vnode->cb_lock);
 		i_size = i_size_read(&vnode->vfs_inode);
 		if (maybe_i_size > i_size)
 			i_size_write(&vnode->vfs_inode, maybe_i_size);
-		spin_unlock(&vnode->wb_lock);
+		write_sequnlock(&vnode->cb_lock);
 	}
 
 	if (!PageUptodate(page)) {