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, 71 insertions, 80 deletions

diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
index dc3ee0cbd77a..3978248247dc 100644
--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -24,18 +24,26 @@
 #include <linux/unaligned.h>
 #include "ecryptfs_kernel.h"
 
-static int lock_parent(struct dentry *dentry,
-		       struct dentry **lower_dentry,
-		       struct inode **lower_dir)
+static struct dentry *ecryptfs_start_creating_dentry(struct dentry *dentry)
 {
-	struct dentry *lower_dir_dentry;
+	struct dentry *parent = dget_parent(dentry);
+	struct dentry *ret;
 
-	lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
-	*lower_dir = d_inode(lower_dir_dentry);
-	*lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	ret = start_creating_dentry(ecryptfs_dentry_to_lower(parent),
+				    ecryptfs_dentry_to_lower(dentry));
+	dput(parent);
+	return ret;
+}
 
-	inode_lock_nested(*lower_dir, I_MUTEX_PARENT);
-	return (*lower_dentry)->d_parent == lower_dir_dentry ? 0 : -EINVAL;
+static struct dentry *ecryptfs_start_removing_dentry(struct dentry *dentry)
+{
+	struct dentry *parent = dget_parent(dentry);
+	struct dentry *ret;
+
+	ret = start_removing_dentry(ecryptfs_dentry_to_lower(parent),
+				    ecryptfs_dentry_to_lower(dentry));
+	dput(parent);
+	return ret;
 }
 
 static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
@@ -141,15 +149,12 @@ static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
 	struct inode *lower_dir;
 	int rc;
 
-	rc = lock_parent(dentry, &lower_dentry, &lower_dir);
-	dget(lower_dentry);	// don't even try to make the lower negative
-	if (!rc) {
-		if (d_unhashed(lower_dentry))
-			rc = -EINVAL;
-		else
-			rc = vfs_unlink(&nop_mnt_idmap, lower_dir, lower_dentry,
-					NULL);
-	}
+	lower_dentry = ecryptfs_start_removing_dentry(dentry);
+	if (IS_ERR(lower_dentry))
+		return PTR_ERR(lower_dentry);
+
+	lower_dir = lower_dentry->d_parent->d_inode;
+	rc = vfs_unlink(&nop_mnt_idmap, lower_dir, lower_dentry, NULL);
 	if (rc) {
 		printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
 		goto out_unlock;
@@ -158,8 +163,7 @@ static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
 	set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
 	inode_set_ctime_to_ts(inode, inode_get_ctime(dir));
 out_unlock:
-	dput(lower_dentry);
-	inode_unlock(lower_dir);
+	end_removing(lower_dentry);
 	if (!rc)
 		d_drop(dentry);
 	return rc;
@@ -186,9 +190,11 @@ ecryptfs_do_create(struct inode *directory_inode,
 	struct inode *lower_dir;
 	struct inode *inode;
 
-	rc = lock_parent(ecryptfs_dentry, &lower_dentry, &lower_dir);
-	if (!rc)
-		rc = vfs_create(&nop_mnt_idmap, lower_dentry, mode, NULL);
+	lower_dentry = ecryptfs_start_creating_dentry(ecryptfs_dentry);
+	if (IS_ERR(lower_dentry))
+		return ERR_CAST(lower_dentry);
+	lower_dir = lower_dentry->d_parent->d_inode;
+	rc = vfs_create(&nop_mnt_idmap, lower_dentry, mode, NULL);
 	if (rc) {
 		printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
 		       "rc = [%d]\n", __func__, rc);
@@ -204,7 +210,7 @@ ecryptfs_do_create(struct inode *directory_inode,
 	fsstack_copy_attr_times(directory_inode, lower_dir);
 	fsstack_copy_inode_size(directory_inode, lower_dir);
 out_lock:
-	inode_unlock(lower_dir);
+	end_creating(lower_dentry);
 	return inode;
 }
 
@@ -432,10 +438,12 @@ static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 
 	file_size_save = i_size_read(d_inode(old_dentry));
 	lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
-	rc = lock_parent(new_dentry, &lower_new_dentry, &lower_dir);
-	if (!rc)
-		rc = vfs_link(lower_old_dentry, &nop_mnt_idmap, lower_dir,
-			      lower_new_dentry, NULL);
+	lower_new_dentry = ecryptfs_start_creating_dentry(new_dentry);
+	if (IS_ERR(lower_new_dentry))
+		return PTR_ERR(lower_new_dentry);
+	lower_dir = lower_new_dentry->d_parent->d_inode;
+	rc = vfs_link(lower_old_dentry, &nop_mnt_idmap, lower_dir,
+		      lower_new_dentry, NULL);
 	if (rc || d_really_is_negative(lower_new_dentry))
 		goto out_lock;
 	rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
@@ -447,7 +455,7 @@ static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
 		  ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
 	i_size_write(d_inode(new_dentry), file_size_save);
 out_lock:
-	inode_unlock(lower_dir);
+	end_creating(lower_new_dentry);
 	return rc;
 }
 
@@ -467,9 +475,11 @@ static int ecryptfs_symlink(struct mnt_idmap *idmap,
 	size_t encoded_symlen;
 	struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
 
-	rc = lock_parent(dentry, &lower_dentry, &lower_dir);
-	if (rc)
-		goto out_lock;
+	lower_dentry = ecryptfs_start_creating_dentry(dentry);
+	if (IS_ERR(lower_dentry))
+		return PTR_ERR(lower_dentry);
+	lower_dir = lower_dentry->d_parent->d_inode;
+
 	mount_crypt_stat = &ecryptfs_superblock_to_private(
 		dir->i_sb)->mount_crypt_stat;
 	rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
@@ -489,7 +499,7 @@ static int ecryptfs_symlink(struct mnt_idmap *idmap,
 	fsstack_copy_attr_times(dir, lower_dir);
 	fsstack_copy_inode_size(dir, lower_dir);
 out_lock:
-	inode_unlock(lower_dir);
+	end_creating(lower_dentry);
 	if (d_really_is_negative(dentry))
 		d_drop(dentry);
 	return rc;
@@ -500,12 +510,14 @@ static struct dentry *ecryptfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 {
 	int rc;
 	struct dentry *lower_dentry;
+	struct dentry *lower_dir_dentry;
 	struct inode *lower_dir;
 
-	rc = lock_parent(dentry, &lower_dentry, &lower_dir);
-	if (rc)
-		goto out;
-
+	lower_dentry = ecryptfs_start_creating_dentry(dentry);
+	if (IS_ERR(lower_dentry))
+		return lower_dentry;
+	lower_dir_dentry = dget(lower_dentry->d_parent);
+	lower_dir = lower_dir_dentry->d_inode;
 	lower_dentry = vfs_mkdir(&nop_mnt_idmap, lower_dir,
 				 lower_dentry, mode, NULL);
 	rc = PTR_ERR(lower_dentry);
@@ -521,7 +533,7 @@ static struct dentry *ecryptfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 	fsstack_copy_inode_size(dir, lower_dir);
 	set_nlink(dir, lower_dir->i_nlink);
 out:
-	inode_unlock(lower_dir);
+	end_creating(lower_dentry);
 	if (d_really_is_negative(dentry))
 		d_drop(dentry);
 	return ERR_PTR(rc);
@@ -533,21 +545,18 @@ static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
 	struct inode *lower_dir;
 	int rc;
 
-	rc = lock_parent(dentry, &lower_dentry, &lower_dir);
-	dget(lower_dentry);	// don't even try to make the lower negative
-	if (!rc) {
-		if (d_unhashed(lower_dentry))
-			rc = -EINVAL;
-		else
-			rc = vfs_rmdir(&nop_mnt_idmap, lower_dir, lower_dentry, NULL);
-	}
+	lower_dentry = ecryptfs_start_removing_dentry(dentry);
+	if (IS_ERR(lower_dentry))
+		return PTR_ERR(lower_dentry);
+	lower_dir = lower_dentry->d_parent->d_inode;
+
+	rc = vfs_rmdir(&nop_mnt_idmap, lower_dir, lower_dentry, NULL);
 	if (!rc) {
 		clear_nlink(d_inode(dentry));
 		fsstack_copy_attr_times(dir, lower_dir);
 		set_nlink(dir, lower_dir->i_nlink);
 	}
-	dput(lower_dentry);
-	inode_unlock(lower_dir);
+	end_removing(lower_dentry);
 	if (!rc)
 		d_drop(dentry);
 	return rc;
@@ -561,10 +570,12 @@ ecryptfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
 	struct dentry *lower_dentry;
 	struct inode *lower_dir;
 
-	rc = lock_parent(dentry, &lower_dentry, &lower_dir);
-	if (!rc)
-		rc = vfs_mknod(&nop_mnt_idmap, lower_dir,
-			       lower_dentry, mode, dev, NULL);
+	lower_dentry = ecryptfs_start_creating_dentry(dentry);
+	if (IS_ERR(lower_dentry))
+		return PTR_ERR(lower_dentry);
+	lower_dir = lower_dentry->d_parent->d_inode;
+
+	rc = vfs_mknod(&nop_mnt_idmap, lower_dir, lower_dentry, mode, dev, NULL);
 	if (rc || d_really_is_negative(lower_dentry))
 		goto out;
 	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
@@ -573,7 +584,7 @@ ecryptfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
 	fsstack_copy_attr_times(dir, lower_dir);
 	fsstack_copy_inode_size(dir, lower_dir);
 out:
-	inode_unlock(lower_dir);
+	end_removing(lower_dentry);
 	if (d_really_is_negative(dentry))
 		d_drop(dentry);
 	return rc;
@@ -589,7 +600,6 @@ ecryptfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 	struct dentry *lower_new_dentry;
 	struct dentry *lower_old_dir_dentry;
 	struct dentry *lower_new_dir_dentry;
-	struct dentry *trap;
 	struct inode *target_inode;
 	struct renamedata rd = {};
 
@@ -604,31 +614,13 @@ ecryptfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 
 	target_inode = d_inode(new_dentry);
 
-	trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
-	if (IS_ERR(trap))
-		return PTR_ERR(trap);
-	dget(lower_new_dentry);
-	rc = -EINVAL;
-	if (lower_old_dentry->d_parent != lower_old_dir_dentry)
-		goto out_lock;
-	if (lower_new_dentry->d_parent != lower_new_dir_dentry)
-		goto out_lock;
-	if (d_unhashed(lower_old_dentry) || d_unhashed(lower_new_dentry))
-		goto out_lock;
-	/* source should not be ancestor of target */
-	if (trap == lower_old_dentry)
-		goto out_lock;
-	/* target should not be ancestor of source */
-	if (trap == lower_new_dentry) {
-		rc = -ENOTEMPTY;
-		goto out_lock;
-	}
+	rd.mnt_idmap  = &nop_mnt_idmap;
+	rd.old_parent = lower_old_dir_dentry;
+	rd.new_parent = lower_new_dir_dentry;
+	rc = start_renaming_two_dentries(&rd, lower_old_dentry, lower_new_dentry);
+	if (rc)
+		return rc;
 
-	rd.mnt_idmap		= &nop_mnt_idmap;
-	rd.old_parent		= lower_old_dir_dentry;
-	rd.old_dentry		= lower_old_dentry;
-	rd.new_parent		= lower_new_dir_dentry;
-	rd.new_dentry		= lower_new_dentry;
 	rc = vfs_rename(&rd);
 	if (rc)
 		goto out_lock;
@@ -639,8 +631,7 @@ ecryptfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 	if (new_dir != old_dir)
 		fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
 out_lock:
-	dput(lower_new_dentry);
-	unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
+	end_renaming(&rd);
 	return rc;
 }