linux-kernel - [PATCH v2 2/6] fs/ntfs3: Move ni_lock_dir and ni_unlock into ntfs_create

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Date:   Thu, 23 Sep 2021 18:42:05 +0300
From:   Konstantin Komarov <almaz.alexandrovich@...agon-software.com>
To:     <ntfs3@...ts.linux.dev>
CC:     <linux-kernel@...r.kernel.org>, <linux-fsdevel@...r.kernel.org>
Subject: [PATCH v2 2/6] fs/ntfs3: Move ni_lock_dir and ni_unlock into
 ntfs_create_inode

Now ntfs3 locks mutex for smaller time.
Theoretically in successful cases those locks aren't needed at all.
But proving the same for error cases is difficult.
So instead of removing them we just move them.

Signed-off-by: Konstantin Komarov <almaz.alexandrovich@...agon-software.com>
---
 fs/ntfs3/inode.c | 17 ++++++++++++++---
 fs/ntfs3/namei.c | 20 --------------------
 2 files changed, 14 insertions(+), 23 deletions(-)

diff --git a/fs/ntfs3/inode.c b/fs/ntfs3/inode.c
index d51bf4018835..7dd162f6a7e2 100644
--- a/fs/ntfs3/inode.c
+++ b/fs/ntfs3/inode.c
@@ -1198,9 +1198,13 @@ struct inode *ntfs_create_inode(struct user_namespace *mnt_userns,
 	struct REPARSE_DATA_BUFFER *rp = NULL;
 	bool rp_inserted = false;
 
+	ni_lock_dir(dir_ni);
+
 	dir_root = indx_get_root(&dir_ni->dir, dir_ni, NULL, NULL);
-	if (!dir_root)
-		return ERR_PTR(-EINVAL);
+	if (!dir_root) {
+		err = -EINVAL;
+		goto out1;
+	}
 
 	if (S_ISDIR(mode)) {
 		/* Use parent's directory attributes. */
@@ -1549,6 +1553,9 @@ struct inode *ntfs_create_inode(struct user_namespace *mnt_userns,
 	if (err)
 		goto out6;
 
+	/* Unlock parent directory before ntfs_init_acl. */
+	ni_unlock(dir_ni);
+
 	inode->i_generation = le16_to_cpu(rec->seq);
 
 	dir->i_mtime = dir->i_ctime = inode->i_atime;
@@ -1605,8 +1612,10 @@ struct inode *ntfs_create_inode(struct user_namespace *mnt_userns,
 out7:
 
 	/* Undo 'indx_insert_entry'. */
+	ni_lock_dir(dir_ni);
 	indx_delete_entry(&dir_ni->dir, dir_ni, new_de + 1,
 			  le16_to_cpu(new_de->key_size), sbi);
+	/* ni_unlock(dir_ni); will be called later. */
 out6:
 	if (rp_inserted)
 		ntfs_remove_reparse(sbi, IO_REPARSE_TAG_SYMLINK, &new_de->ref);
@@ -1630,8 +1639,10 @@ struct inode *ntfs_create_inode(struct user_namespace *mnt_userns,
 	kfree(rp);
 
 out1:
-	if (err)
+	if (err) {
+		ni_unlock(dir_ni);
 		return ERR_PTR(err);
+	}
 
 	unlock_new_inode(inode);
 
diff --git a/fs/ntfs3/namei.c b/fs/ntfs3/namei.c
index 1c475da4e19d..bc741213ad84 100644
--- a/fs/ntfs3/namei.c
+++ b/fs/ntfs3/namei.c
@@ -95,16 +95,11 @@ static struct dentry *ntfs_lookup(struct inode *dir, struct dentry *dentry,
 static int ntfs_create(struct user_namespace *mnt_userns, struct inode *dir,
 		       struct dentry *dentry, umode_t mode, bool excl)
 {
-	struct ntfs_inode *ni = ntfs_i(dir);
 	struct inode *inode;
 
-	ni_lock_dir(ni);
-
 	inode = ntfs_create_inode(mnt_userns, dir, dentry, NULL, S_IFREG | mode,
 				  0, NULL, 0, NULL);
 
-	ni_unlock(ni);
-
 	return IS_ERR(inode) ? PTR_ERR(inode) : 0;
 }
 
@@ -116,16 +111,11 @@ static int ntfs_create(struct user_namespace *mnt_userns, struct inode *dir,
 static int ntfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
 		      struct dentry *dentry, umode_t mode, dev_t rdev)
 {
-	struct ntfs_inode *ni = ntfs_i(dir);
 	struct inode *inode;
 
-	ni_lock_dir(ni);
-
 	inode = ntfs_create_inode(mnt_userns, dir, dentry, NULL, mode, rdev,
 				  NULL, 0, NULL);
 
-	ni_unlock(ni);
-
 	return IS_ERR(inode) ? PTR_ERR(inode) : 0;
 }
 
@@ -196,15 +186,10 @@ static int ntfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
 {
 	u32 size = strlen(symname);
 	struct inode *inode;
-	struct ntfs_inode *ni = ntfs_i(dir);
-
-	ni_lock_dir(ni);
 
 	inode = ntfs_create_inode(mnt_userns, dir, dentry, NULL, S_IFLNK | 0777,
 				  0, symname, size, NULL);
 
-	ni_unlock(ni);
-
 	return IS_ERR(inode) ? PTR_ERR(inode) : 0;
 }
 
@@ -215,15 +200,10 @@ static int ntfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
 		      struct dentry *dentry, umode_t mode)
 {
 	struct inode *inode;
-	struct ntfs_inode *ni = ntfs_i(dir);
-
-	ni_lock_dir(ni);
 
 	inode = ntfs_create_inode(mnt_userns, dir, dentry, NULL, S_IFDIR | mode,
 				  0, NULL, 0, NULL);
 
-	ni_unlock(ni);
-
 	return IS_ERR(inode) ? PTR_ERR(inode) : 0;
 }
 
-- 
2.33.0