[PATCH 5.10 36/79] smb3: missing inode locks in punch hole

Greg Kroah-Hartman
2022-09-13T14:45:48Z

From: David Howells <dhowells@redhat.com>

[ Upstream commit ba0803050d610d5072666be727bca5e03e55b242 ]

smb3 fallocate punch hole was not grabbing the inode or filemap_invalidate
locks so could have race with pagemap reinstantiating the page.

Cc: stable@vger.kernel.org
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/cifs/smb2ops.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 0a20ae96fe243..11efd5289ec43 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -3430,7 +3430,7 @@ static long smb3_zero_range(struct file *file, struct cifs_tcon *tcon,
static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon,
loff_t offset, loff_t len)
{
- struct inode *inode;
+ struct inode *inode = file_inode(file);
struct cifsFileInfo *cfile = file->private_data;
struct file_zero_data_information fsctl_buf;
long rc;
@@ -3439,14 +3439,12 @@ static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon,

xid = get_xid();

- inode = d_inode(cfile->dentry);
-
+ inode_lock(inode);
/* Need to make file sparse, if not already, before freeing range. */
/* Consider adding equivalent for compressed since it could also work */
if (!smb2_set_sparse(xid, tcon, cfile, inode, set_sparse)) {
rc = -EOPNOTSUPP;
- free_xid(xid);
- return rc;
+ goto out;
}

/*
@@ -3465,6 +3463,8 @@ static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon,
(char *)&fsctl_buf,
sizeof(struct file_zero_data_information),
CIFSMaxBufSize, NULL, NULL);
+out:
+ inode_unlock(inode);
free_xid(xid);
return rc;
}
--
2.35.1