smb3: fix temporary data corruption in collapse range

collapse range doesn't discard the affected cached region
so can risk temporarily corrupting the file data. This
fixes xfstest generic/031

I also decided to merge a minor cleanup to this into the same patch
(avoiding rereading inode size repeatedly unnecessarily) to make it
clearer.

Cc: stable@vger.kernel.org
Fixes: 5476b5dd82 ("cifs: add support for FALLOC_FL_COLLAPSE_RANGE")
Reported-by: David Howells <dhowells@redhat.com>
Tested-by: David Howells <dhowells@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
cc: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Steve French 2022-08-23 14:07:41 +01:00
parent c3a72bb213
commit fa30a81f25

View File

@ -3669,41 +3669,47 @@ static long smb3_collapse_range(struct file *file, struct cifs_tcon *tcon,
{
int rc;
unsigned int xid;
struct inode *inode;
struct inode *inode = file_inode(file);
struct cifsFileInfo *cfile = file->private_data;
struct cifsInodeInfo *cifsi;
struct cifsInodeInfo *cifsi = CIFS_I(inode);
__le64 eof;
loff_t old_eof;
xid = get_xid();
inode = d_inode(cfile->dentry);
cifsi = CIFS_I(inode);
inode_lock(inode);
if (off >= i_size_read(inode) ||
off + len >= i_size_read(inode)) {
old_eof = i_size_read(inode);
if ((off >= old_eof) ||
off + len >= old_eof) {
rc = -EINVAL;
goto out;
}
filemap_invalidate_lock(inode->i_mapping);
filemap_write_and_wait(inode->i_mapping);
truncate_pagecache_range(inode, off, old_eof);
rc = smb2_copychunk_range(xid, cfile, cfile, off + len,
i_size_read(inode) - off - len, off);
old_eof - off - len, off);
if (rc < 0)
goto out;
goto out_2;
eof = cpu_to_le64(i_size_read(inode) - len);
eof = cpu_to_le64(old_eof - len);
rc = SMB2_set_eof(xid, tcon, cfile->fid.persistent_fid,
cfile->fid.volatile_fid, cfile->pid, &eof);
if (rc < 0)
goto out;
goto out_2;
rc = 0;
cifsi->server_eof = i_size_read(inode) - len;
truncate_setsize(inode, cifsi->server_eof);
fscache_resize_cookie(cifs_inode_cookie(inode), cifsi->server_eof);
out_2:
filemap_invalidate_unlock(inode->i_mapping);
out:
inode_unlock(inode);
free_xid(xid);
return rc;
}