bcachefs: Switch to .iterate_shared for readdir

We definitely don't need an exclusive inode lock for readdir.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/fs.c

@@ -367,12 +367,12 @@ static struct dentry *bch2_lookup(struct inode *vdir, struct dentry *dentry,
 	return d_splice_alias(vinode, dentry);
 }
 
-static int bch2_create(struct mnt_idmap *idmap,
+static int bch2_mknod(struct mnt_idmap *idmap,
 		      struct inode *vdir, struct dentry *dentry,
-		       umode_t mode, bool excl)
+		      umode_t mode, dev_t rdev)
 {
 	struct bch_inode_info *inode =
-		__bch2_create(idmap, to_bch_ei(vdir), dentry, mode|S_IFREG, 0, false);
+		__bch2_create(idmap, to_bch_ei(vdir), dentry, mode, rdev, false);
 
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);
@@ -381,6 +381,13 @@ static int bch2_create(struct mnt_idmap *idmap,
 	return 0;
 }
 
+static int bch2_create(struct mnt_idmap *idmap,
+		       struct inode *vdir, struct dentry *dentry,
+		       umode_t mode, bool excl)
+{
+	return bch2_mknod(idmap, vdir, dentry, mode|S_IFREG, 0);
+}
+
 static int __bch2_link(struct bch_fs *c,
 		       struct bch_inode_info *inode,
 		       struct bch_inode_info *dir,
@@ -512,33 +519,7 @@ static int bch2_symlink(struct mnt_idmap *idmap,
 static int bch2_mkdir(struct mnt_idmap *idmap,
 		      struct inode *vdir, struct dentry *dentry, umode_t mode)
 {
-	struct bch_inode_info *inode =
-		__bch2_create(idmap, to_bch_ei(vdir), dentry, mode|S_IFDIR, 0, false);
-
-	if (IS_ERR(inode))
-		return PTR_ERR(inode);
-
-	d_instantiate(dentry, &inode->v);
-	return 0;
-}
-
-static int bch2_rmdir(struct inode *vdir, struct dentry *dentry)
-{
-	return bch2_unlink(vdir, dentry);
-}
-
-static int bch2_mknod(struct mnt_idmap *idmap,
-		      struct inode *vdir, struct dentry *dentry,
-		      umode_t mode, dev_t rdev)
-{
-	struct bch_inode_info *inode =
-		__bch2_create(idmap, to_bch_ei(vdir), dentry, mode, rdev, false);
-
-	if (IS_ERR(inode))
-		return PTR_ERR(inode);
-
-	d_instantiate(dentry, &inode->v);
-	return 0;
+	return bch2_mknod(idmap, vdir, dentry, mode|S_IFDIR, 0);
 }
 
 static int bch2_rename2(struct mnt_idmap *idmap,
@@ -1034,7 +1015,7 @@ static const struct inode_operations bch_dir_inode_operations = {
 	.unlink		= bch2_unlink,
 	.symlink	= bch2_symlink,
 	.mkdir		= bch2_mkdir,
-	.rmdir		= bch2_rmdir,
+	.rmdir		= bch2_unlink,
 	.mknod		= bch2_mknod,
 	.rename		= bch2_rename2,
 	.getattr	= bch2_getattr,