smb/server: use end_removing_noperm for for target of smb2_create_link()

Sometimes smb2_create_link() needs to remove the target before creating
the link.
It uses ksmbd_vfs_kern_locked(), and is the only user of that interface.

To match the new naming, that function is changed to
ksmbd_vfs_kern_start_removing(), and related functions or flags are also
renamed.

The lock actually happens in ksmbd_vfs_path_lookup() and that is changed
to use start_removing_noperm() - permission to perform lookup in the
parent was already checked in vfs_path_parent_lookup().

Signed-off-by: NeilBrown <neil@brown.name>
Link: https://patch.msgid.link/20251113002050.676694-8-neilb@ownmail.net
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index ab1d45fcebdef1c805ce830e14c1de44b01c7098..752614f35b569d7abe6982b8ed69363be6410224 100644 (file)
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -6084,8 +6084,8 @@ static int smb2_create_link(struct ksmbd_work *work,
        }
 
        ksmbd_debug(SMB, "target name is %s\n", target_name);
-       rc = ksmbd_vfs_kern_path_locked(work, link_name, LOOKUP_NO_SYMLINKS,
-                                       &path, 0);
+       rc = ksmbd_vfs_kern_path_start_removing(work, link_name, LOOKUP_NO_SYMLINKS,
+                                               &path, 0);
        if (rc) {
                if (rc != -ENOENT)
                        goto out;
@@ -6103,7 +6103,7 @@ static int smb2_create_link(struct ksmbd_work *work,
                        ksmbd_debug(SMB, "link already exists\n");
                        goto out;
                }
-               ksmbd_vfs_kern_path_unlock(&path);
+               ksmbd_vfs_kern_path_end_removing(&path);
        }
        rc = ksmbd_vfs_link(work, target_name, link_name);
        if (rc)

diff --git a/fs/smb/server/vfs.c b/fs/smb/server/vfs.c
index 891ed2dc2b7351a5cb14a2241d71095ffdd03f08..ea0a06b0ae4461ed2b49e816594586f4769a5f92 100644 (file)
--- a/fs/smb/server/vfs.c
+++ b/fs/smb/server/vfs.c
@@ -69,7 +69,7 @@ int ksmbd_vfs_lock_parent(struct dentry *parent, struct dentry *child)
 
 static int ksmbd_vfs_path_lookup(struct ksmbd_share_config *share_conf,
                                 char *pathname, unsigned int flags,
-                                struct path *path, bool do_lock)
+                                struct path *path, bool for_remove)
 {
        struct qstr last;
        struct filename *filename __free(putname) = NULL;
@@ -99,22 +99,20 @@ static int ksmbd_vfs_path_lookup(struct ksmbd_share_config *share_conf,
                return -ENOENT;
        }
 
-       if (do_lock) {
+       if (for_remove) {
                err = mnt_want_write(path->mnt);
                if (err) {
                        path_put(path);
                        return -ENOENT;
                }
 
-               inode_lock_nested(path->dentry->d_inode, I_MUTEX_PARENT);
-               d = lookup_one_qstr_excl(&last, path->dentry, 0);
+               d = start_removing_noperm(path->dentry, &last);
 
                if (!IS_ERR(d)) {
                        dput(path->dentry);
                        path->dentry = d;
                        return 0;
                }
-               inode_unlock(path->dentry->d_inode);
                mnt_drop_write(path->mnt);
                path_put(path);
                return -ENOENT;
@@ -1207,7 +1205,7 @@ static int ksmbd_vfs_lookup_in_dir(const struct path *dir, char *name,
 static
 int __ksmbd_vfs_kern_path(struct ksmbd_work *work, char *filepath,
                          unsigned int flags,
-                         struct path *path, bool caseless, bool do_lock)
+                         struct path *path, bool caseless, bool for_remove)
 {
        struct ksmbd_share_config *share_conf = work->tcon->share_conf;
        struct path parent_path;
@@ -1215,7 +1213,7 @@ int __ksmbd_vfs_kern_path(struct ksmbd_work *work, char *filepath,
        int err;
 
 retry:
-       err = ksmbd_vfs_path_lookup(share_conf, filepath, flags, path, do_lock);
+       err = ksmbd_vfs_path_lookup(share_conf, filepath, flags, path, for_remove);
        if (!err || !caseless)
                return err;
 
@@ -1286,7 +1284,7 @@ int ksmbd_vfs_kern_path(struct ksmbd_work *work, char *filepath,
 }
 
 /**
- * ksmbd_vfs_kern_path_locked() - lookup a file and get path info
+ * ksmbd_vfs_kern_path_start_remove() - lookup a file and get path info prior to removal
  * @work:              work
  * @filepath:          file path that is relative to share
  * @flags:             lookup flags
@@ -1298,20 +1296,19 @@ int ksmbd_vfs_kern_path(struct ksmbd_work *work, char *filepath,
  * filesystem will have been gained.
  * Return:     0 on if file was found, otherwise error
  */
-int ksmbd_vfs_kern_path_locked(struct ksmbd_work *work, char *filepath,
-                              unsigned int flags,
-                              struct path *path, bool caseless)
+int ksmbd_vfs_kern_path_start_removing(struct ksmbd_work *work, char *filepath,
+                                      unsigned int flags,
+                                      struct path *path, bool caseless)
 {
        return __ksmbd_vfs_kern_path(work, filepath, flags, path,
                                     caseless, true);
 }
 
-void ksmbd_vfs_kern_path_unlock(const struct path *path)
+void ksmbd_vfs_kern_path_end_removing(const struct path *path)
 {
-       /* While lock is still held, ->d_parent is safe */
-       inode_unlock(d_inode(path->dentry->d_parent));
+       end_removing(path->dentry);
        mnt_drop_write(path->mnt);
-       path_put(path);
+       mntput(path->mnt);
 }
 
 struct dentry *ksmbd_vfs_kern_path_create(struct ksmbd_work *work,

diff --git a/fs/smb/server/vfs.h b/fs/smb/server/vfs.h
index df6421b4590baea593a7f20fc64d5ed1e9067ea7..16ca29ee16e5159547e4fc7907c59fec8ff3c9f4 100644 (file)
--- a/fs/smb/server/vfs.h
+++ b/fs/smb/server/vfs.h
@@ -120,10 +120,10 @@ int ksmbd_vfs_remove_xattr(struct mnt_idmap *idmap,
 int ksmbd_vfs_kern_path(struct ksmbd_work *work, char *name,
                        unsigned int flags,
                        struct path *path, bool caseless);
-int ksmbd_vfs_kern_path_locked(struct ksmbd_work *work, char *name,
-                              unsigned int flags,
-                              struct path *path, bool caseless);
-void ksmbd_vfs_kern_path_unlock(const struct path *path);
+int ksmbd_vfs_kern_path_start_removing(struct ksmbd_work *work, char *name,
+                                      unsigned int flags,
+                                      struct path *path, bool caseless);
+void ksmbd_vfs_kern_path_end_removing(const struct path *path);
 struct dentry *ksmbd_vfs_kern_path_create(struct ksmbd_work *work,
                                          const char *name,
                                          unsigned int flags,