ksmbd: fix missing use of get_write in in smb2_set_ea()

Fix an issue where get_write is not used in smb2_set_ea().

Fixes: 6fc0a26 ("ksmbd: fix potential circular locking issue in smb2_set_ea()")
Cc: stable@vger.kernel.org
Reported-by: Wang Zhaolong <wangzhaolong1@huawei.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: namjaejeon

fs/smb/server/smb2pdu.c

@@ -2367,7 +2367,8 @@ static int smb2_set_ea(struct smb2_ea_info *eabuf, unsigned int buf_len,
 			if (rc > 0) {
 				rc = ksmbd_vfs_remove_xattr(idmap,
 							    path,
-							    attr_name);
+							    attr_name,
+							    get_write);
 
 				if (rc < 0) {
 					ksmbd_debug(SMB,
@@ -2382,7 +2383,7 @@ static int smb2_set_ea(struct smb2_ea_info *eabuf, unsigned int buf_len,
 		} else {
 			rc = ksmbd_vfs_setxattr(idmap, path, attr_name, value,
 						le16_to_cpu(eabuf->EaValueLength),
-						0, true);
+						0, get_write);
 			if (rc < 0) {
 				ksmbd_debug(SMB,
 					    "ksmbd_vfs_setxattr is failed(%d)\n",
@@ -2474,7 +2475,7 @@ static int smb2_remove_smb_xattrs(const struct path *path)
 		    !strncmp(&name[XATTR_USER_PREFIX_LEN], STREAM_PREFIX,
 			     STREAM_PREFIX_LEN)) {
 			err = ksmbd_vfs_remove_xattr(idmap, path,
-						     name);
+						     name, true);
 			if (err)
 				ksmbd_debug(SMB, "remove xattr failed : %s\n",
 					    name);

fs/smb/server/vfs.c

@@ -1058,16 +1058,21 @@ int ksmbd_vfs_fqar_lseek(struct ksmbd_file *fp, loff_t start, loff_t length,
 }
 
 int ksmbd_vfs_remove_xattr(struct mnt_idmap *idmap,
-			   const struct path *path, char *attr_name)
+			   const struct path *path, char *attr_name,
+			   bool get_write)
 {
 	int err;
 
-	err = mnt_want_write(path->mnt);
-	if (err)
-		return err;
+	if (get_write == true) {
+		err = mnt_want_write(path->mnt);
+		if (err)
+			return err;
+	}
 
 	err = vfs_removexattr(idmap, path->dentry, attr_name);
-	mnt_drop_write(path->mnt);
+
+	if (get_write == true)
+		mnt_drop_write(path->mnt);
 
 	return err;
 }
@@ -1380,7 +1385,7 @@ int ksmbd_vfs_remove_sd_xattrs(struct mnt_idmap *idmap, const struct path *path)
 		ksmbd_debug(SMB, "%s, len %zd\n", name, strlen(name));
 
 		if (!strncmp(name, XATTR_NAME_SD, XATTR_NAME_SD_LEN)) {
-			err = ksmbd_vfs_remove_xattr(idmap, path, name);
+			err = ksmbd_vfs_remove_xattr(idmap, path, name, true);
 			if (err)
 				ksmbd_debug(SMB, "remove xattr failed : %s\n", name);
 		}

fs/smb/server/vfs.h

@@ -114,7 +114,8 @@ int ksmbd_vfs_setxattr(struct mnt_idmap *idmap,
 int ksmbd_vfs_xattr_stream_name(char *stream_name, char **xattr_stream_name,
 				size_t *xattr_stream_name_size, int s_type);
 int ksmbd_vfs_remove_xattr(struct mnt_idmap *idmap,
-			   const struct path *path, char *attr_name);
+			   const struct path *path, char *attr_name,
+			   bool get_write);
 int ksmbd_vfs_kern_path_locked(struct ksmbd_work *work, char *name,
 			       unsigned int flags, struct path *parent_path,
 			       struct path *path, bool caseless);

fs/smb/server/vfs_cache.c

@@ -254,7 +254,8 @@ static void __ksmbd_inode_close(struct ksmbd_file *fp)
 		ci->m_flags &= ~S_DEL_ON_CLS_STREAM;
 		err = ksmbd_vfs_remove_xattr(file_mnt_idmap(filp),
 					     &filp->f_path,
-					     fp->stream.name);
+					     fp->stream.name,
+					     true);
 		if (err)
 			pr_err("remove xattr failed : %s\n",
 			       fp->stream.name);