[PATCH 2/2] staging: lustre: replace ll_{get, put}name() with {get, put}name()

[Boqun Feng <boqun.feng@gmail.com>]

As pointed by Al Viro:

https://lkml.org/lkml/2015/4/11/243

There are bugs in ll_getname() because of wrong assumptions of returning
values from strncpy_from_user(). Moreover, what ll_getname want to do is
just to try copy the file name from userland. Since we already have
getname() for the same purpose, it's better to replace ll_getname() with
getname(), so is ll_putname().

Besides, remove unused code for checking whether namelen is 0 or not in
case LL_IOC_REMOVE_ENTRY, because zero-length file name is already
handled by getname() in the same way as ll_getname().

Suggested-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
 drivers/staging/lustre/lustre/llite/dir.c          | 60 ++++++----------------
 .../staging/lustre/lustre/llite/llite_internal.h   |  2 +-
 drivers/staging/lustre/lustre/llite/namei.c        |  2 +-
 3 files changed, 18 insertions(+), 46 deletions(-)

diff --git a/drivers/staging/lustre/lustre/llite/dir.c b/drivers/staging/lustre/lustre/llite/dir.c
index a182019..c75fc38 100644
--- a/drivers/staging/lustre/lustre/llite/dir.c
+++ b/drivers/staging/lustre/lustre/llite/dir.c
@@ -1216,30 +1216,6 @@ out:
 	return rc;
 }
 
-static char *
-ll_getname(const char __user *filename)
-{
-	int ret = 0, len;
-	char *tmp = __getname();
-
-	if (!tmp)
-		return ERR_PTR(-ENOMEM);
-
-	len = strncpy_from_user(tmp, filename, PATH_MAX);
-	if (len == 0)
-		ret = -ENOENT;
-	else if (len > PATH_MAX)
-		ret = -ENAMETOOLONG;
-
-	if (ret) {
-		__putname(tmp);
-		tmp =  ERR_PTR(ret);
-	}
-	return tmp;
-}
-
-#define ll_putname(filename) __putname(filename)
-
 static long ll_dir_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	struct inode *inode = file_inode(file);
@@ -1441,7 +1417,7 @@ free_lmv:
 		return rc;
 	}
 	case LL_IOC_REMOVE_ENTRY: {
-		char		*filename = NULL;
+		struct filename *name = NULL;
 		int		 namelen = 0;
 		int		 rc;
 
@@ -1453,20 +1429,16 @@ free_lmv:
 		if (!(exp_connect_flags(sbi->ll_md_exp) & OBD_CONNECT_LVB_TYPE))
 			return -ENOTSUPP;
 
-		filename = ll_getname((const char *)arg);
-		if (IS_ERR(filename))
-			return PTR_ERR(filename);
+		name = getname((const char *)arg);
+		if (IS_ERR(name))
+			return PTR_ERR(name);
 
-		namelen = strlen(filename);
-		if (namelen < 1) {
-			rc = -EINVAL;
-			goto out_rmdir;
-		}
+		namelen = strlen(name->name);
+
+		rc = ll_rmdir_entry(inode, name->name, namelen);
 
-		rc = ll_rmdir_entry(inode, filename, namelen);
-out_rmdir:
-		if (filename)
-			ll_putname(filename);
+		if (name)
+			putname(name);
 		return rc;
 	}
 	case LL_IOC_LOV_SWAP_LAYOUTS:
@@ -1481,16 +1453,16 @@ out_rmdir:
 		struct lov_user_md *lump;
 		struct lov_mds_md *lmm = NULL;
 		struct mdt_body *body;
-		char *filename = NULL;
+		struct filename *name = NULL;
 		int lmmsize;
 
 		if (cmd == IOC_MDC_GETFILEINFO ||
 		    cmd == IOC_MDC_GETFILESTRIPE) {
-			filename = ll_getname((const char *)arg);
-			if (IS_ERR(filename))
-				return PTR_ERR(filename);
+			name = getname((const char *)arg);
+			if (IS_ERR(name))
+				return PTR_ERR(name);
 
-			rc = ll_lov_getstripe_ea_info(inode, filename, &lmm,
+			rc = ll_lov_getstripe_ea_info(inode, name->name, &lmm,
 						      &lmmsize, &request);
 		} else {
 			rc = ll_dir_getstripe(inode, &lmm, &lmmsize, &request);
@@ -1556,8 +1528,8 @@ skip_lmm:
 
 out_req:
 		ptlrpc_req_finished(request);
-		if (filename)
-			ll_putname(filename);
+		if (name)
+			putname(name);
 		return rc;
 	}
 	case IOC_LOV_GETINFO: {
diff --git a/drivers/staging/lustre/lustre/llite/llite_internal.h b/drivers/staging/lustre/lustre/llite/llite_internal.h
index 2af1d72..0950565 100644
--- a/drivers/staging/lustre/lustre/llite/llite_internal.h
+++ b/drivers/staging/lustre/lustre/llite/llite_internal.h
@@ -714,7 +714,7 @@ struct inode *ll_iget(struct super_block *sb, ino_t hash,
 int ll_md_blocking_ast(struct ldlm_lock *, struct ldlm_lock_desc *,
 		       void *data, int flag);
 struct dentry *ll_splice_alias(struct inode *inode, struct dentry *de);
-int ll_rmdir_entry(struct inode *dir, char *name, int namelen);
+int ll_rmdir_entry(struct inode *dir, const char *name, int namelen);
 
 /* llite/rw.c */
 int ll_prepare_write(struct file *, struct page *, unsigned from, unsigned to);
diff --git a/drivers/staging/lustre/lustre/llite/namei.c b/drivers/staging/lustre/lustre/llite/namei.c
index 890ac19..ec48d8d 100644
--- a/drivers/staging/lustre/lustre/llite/namei.c
+++ b/drivers/staging/lustre/lustre/llite/namei.c
@@ -867,7 +867,7 @@ static inline void ll_get_child_fid(struct dentry *child, struct lu_fid *fid)
 /**
  * Remove dir entry
  **/
-int ll_rmdir_entry(struct inode *dir, char *name, int namelen)
+int ll_rmdir_entry(struct inode *dir, const char *name, int namelen)
 {
 	struct ptlrpc_request *request = NULL;
 	struct md_op_data *op_data;
-- 
2.3.5