Merge tag 'vfs-6.19-rc1.directory.locking' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull directory locking updates from Christian Brauner:
 "This contains the work to add centralized APIs for directory locking
  operations.

  This series is part of a larger effort to change directory operation
  locking to allow multiple concurrent operations in a directory. The
  ultimate goal is to lock the target dentry(s) rather than the whole
  parent directory.

  To help with changing the locking protocol, this series centralizes
  locking and lookup in new helper functions. The helpers establish a
  pattern where it is the dentry that is being locked and unlocked
  (currently the lock is held on dentry->d_parent->d_inode, but that can
  change in the future).

  This also changes vfs_mkdir() to unlock the parent on failure, as well
  as dput()ing the dentry. This allows end_creating() to only require
  the target dentry (which may be IS_ERR() after vfs_mkdir()), not the
  parent"

* tag 'vfs-6.19-rc1.directory.locking' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  nfsd: fix end_creating() conversion
  VFS: introduce end_creating_keep()
  VFS: change vfs_mkdir() to unlock on failure.
  ecryptfs: use new start_creating/start_removing APIs
  Add start_renaming_two_dentries()
  VFS/ovl/smb: introduce start_renaming_dentry()
  VFS/nfsd/ovl: introduce start_renaming() and end_renaming()
  VFS: add start_creating_killable() and start_removing_killable()
  VFS: introduce start_removing_dentry()
  smb/server: use end_removing_noperm for for target of smb2_create_link()
  VFS: introduce start_creating_noperm() and start_removing_noperm()
  VFS/nfsd/cachefiles/ovl: introduce start_removing() and end_removing()
  VFS/nfsd/cachefiles/ovl: add start_creating() and end_creating()
  VFS: tidy up do_unlinkat()
  VFS: introduce start_dirop() and end_dirop()
  debugfs: rename end_creating() to debugfs_end_creating()

1 files changed, 82 insertions, 0 deletions

diff --git a/include/linux/namei.h b/include/linux/namei.h
index b0679c7420a8..58600cf234bc 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -89,6 +89,81 @@ struct dentry *lookup_one_positive_killable(struct mnt_idmap *idmap,
 					    struct qstr *name,
 					    struct dentry *base);
 
+struct dentry *start_creating(struct mnt_idmap *idmap, struct dentry *parent,
+			      struct qstr *name);
+struct dentry *start_removing(struct mnt_idmap *idmap, struct dentry *parent,
+			      struct qstr *name);
+struct dentry *start_creating_killable(struct mnt_idmap *idmap,
+				       struct dentry *parent,
+				       struct qstr *name);
+struct dentry *start_removing_killable(struct mnt_idmap *idmap,
+				       struct dentry *parent,
+				       struct qstr *name);
+struct dentry *start_creating_noperm(struct dentry *parent, struct qstr *name);
+struct dentry *start_removing_noperm(struct dentry *parent, struct qstr *name);
+struct dentry *start_creating_dentry(struct dentry *parent,
+				     struct dentry *child);
+struct dentry *start_removing_dentry(struct dentry *parent,
+				     struct dentry *child);
+
+/* end_creating - finish action started with start_creating
+ * @child: dentry returned by start_creating() or vfs_mkdir()
+ *
+ * Unlock and release the child. This can be called after
+ * start_creating() whether that function succeeded or not,
+ * but it is not needed on failure.
+ *
+ * If vfs_mkdir() was called then the value returned from that function
+ * should be given for @child rather than the original dentry, as vfs_mkdir()
+ * may have provided a new dentry.
+ *
+ *
+ * If vfs_mkdir() was not called, then @child will be a valid dentry and
+ * @parent will be ignored.
+ */
+static inline void end_creating(struct dentry *child)
+{
+	end_dirop(child);
+}
+
+/* end_creating_keep - finish action started with start_creating() and return result
+ * @child: dentry returned by start_creating() or vfs_mkdir()
+ *
+ * Unlock and return the child. This can be called after
+ * start_creating() whether that function succeeded or not,
+ * but it is not needed on failure.
+ *
+ * If vfs_mkdir() was called then the value returned from that function
+ * should be given for @child rather than the original dentry, as vfs_mkdir()
+ * may have provided a new dentry.
+ *
+ * Returns: @child, which may be a dentry or an error.
+ *
+ */
+static inline struct dentry *end_creating_keep(struct dentry *child)
+{
+	if (!IS_ERR(child))
+		dget(child);
+	end_dirop(child);
+	return child;
+}
+
+/**
+ * end_removing - finish action started with start_removing
+ * @child:  dentry returned by start_removing()
+ * @parent: dentry given to start_removing()
+ *
+ * Unlock and release the child.
+ *
+ * This is identical to end_dirop().  It can be passed the result of
+ * start_removing() whether that was successful or not, but it not needed
+ * if start_removing() failed.
+ */
+static inline void end_removing(struct dentry *child)
+{
+	end_dirop(child);
+}
+
 extern int follow_down_one(struct path *);
 extern int follow_down(struct path *path, unsigned int flags);
 extern int follow_up(struct path *);
@@ -96,6 +171,13 @@ extern int follow_up(struct path *);
 extern struct dentry *lock_rename(struct dentry *, struct dentry *);
 extern struct dentry *lock_rename_child(struct dentry *, struct dentry *);
 extern void unlock_rename(struct dentry *, struct dentry *);
+int start_renaming(struct renamedata *rd, int lookup_flags,
+		   struct qstr *old_last, struct qstr *new_last);
+int start_renaming_dentry(struct renamedata *rd, int lookup_flags,
+			  struct dentry *old_dentry, struct qstr *new_last);
+int start_renaming_two_dentries(struct renamedata *rd,
+				struct dentry *old_dentry, struct dentry *new_dentry);
+void end_renaming(struct renamedata *rd);
 
 /**
  * mode_strip_umask - handle vfs umask stripping