[PATCH 5.15 115/136] smb3: missing inode locks in punch hole

Greg Kroah-Hartman
2022-08-29T11:21:12Z

From: David Howells <dhowells@redhat.com>

commit ba0803050d610d5072666be727bca5e03e55b242 upstream.

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/cifs/smb2ops.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -3599,7 +3599,7 @@ static long smb3_zero_range(struct file
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;
@@ -3608,14 +3608,12 @@ static long smb3_punch_hole(struct file

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;
}

filemap_invalidate_lock(inode->i_mapping);
@@ -3635,8 +3633,10 @@ static long smb3_punch_hole(struct file
true /* is_fctl */, (char *)&fsctl_buf,
sizeof(struct file_zero_data_information),
CIFSMaxBufSize, NULL, NULL);
- free_xid(xid);
filemap_invalidate_unlock(inode->i_mapping);
+out:
+ inode_unlock(inode);
+ free_xid(xid);
return rc;
}