[PATCH 5.4 265/388] fuse: update attr_version counter on fuse_notify_inval_inode()

[Greg Kroah-Hartman]

From: Miklos Szeredi <mszeredi@xxxxxxxxxx>

[ Upstream commit 5ddd9ced9aef6cfa76af27d384c17c9e2d610ce8 ]

A GETATTR request can race with FUSE_NOTIFY_INVAL_INODE, resulting in the
attribute cache being updated with stale information after the
invalidation.

Fix this by bumping the attribute version in fuse_reverse_inval_inode().

Reported-by: Krzysztof Rusek <rusek@xxxxxxxxxxxxxx>
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 fs/fuse/inode.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 5dca643a257c9..f58ab84b09fb3 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -323,6 +323,8 @@ struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
 int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
 			     loff_t offset, loff_t len)
 {
+	struct fuse_conn *fc = get_fuse_conn_super(sb);
+	struct fuse_inode *fi;
 	struct inode *inode;
 	pgoff_t pg_start;
 	pgoff_t pg_end;
@@ -331,6 +333,11 @@ int fuse_reverse_inval_inode(struct super_block *sb, u64 nodeid,
 	if (!inode)
 		return -ENOENT;
 
+	fi = get_fuse_inode(inode);
+	spin_lock(&fi->lock);
+	fi->attr_version = atomic64_inc_return(&fc->attr_version);
+	spin_unlock(&fi->lock);
+
 	fuse_invalidate_attr(inode);
 	forget_all_cached_acls(inode);
 	if (offset >= 0) {
-- 
2.25.1