[RFC v2 53/83] Namei: lookup.

Andiry Xu
2018-03-10T18:21:34Z

NOVA lookup the inode number by searching the radix tree with
the filename hash value and locating the corresponding dentry on the log.

Signed-off-by: Andiry Xu <jix024@cs.ucsd.edu>
---
fs/nova/Makefile | 3 +-
fs/nova/inode.c | 2 ++
fs/nova/namei.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/nova/nova.h | 4 +++
4 files changed, 105 insertions(+), 1 deletion(-)
create mode 100644 fs/nova/namei.c

diff --git a/fs/nova/Makefile b/fs/nova/Makefile
index 3a3243c..eb97e46 100644
--- a/fs/nova/Makefile
+++ b/fs/nova/Makefile
@@ -4,4 +4,5 @@

obj-$(CONFIG_NOVA_FS) += nova.o

-nova-y := balloc.o bbuild.o dir.o inode.o journal.o log.o rebuild.o stats.o super.o
+nova-y := balloc.o bbuild.o dir.o inode.o journal.o log.o namei.o\
+ rebuild.o stats.o super.o
diff --git a/fs/nova/inode.c b/fs/nova/inode.c
index 17addd3..2d3f7a3 100644
--- a/fs/nova/inode.c
+++ b/fs/nova/inode.c
@@ -181,6 +181,7 @@ static int nova_read_inode(struct super_block *sb, struct inode *inode,
case S_IFREG:
break;
case S_IFDIR:
+ inode->i_op = &nova_dir_inode_operations;
inode->i_fop = &nova_dir_operations;
break;
case S_IFLNK:
@@ -881,6 +882,7 @@ struct inode *nova_new_vfs_inode(enum nova_new_inode_type type,
inode->i_mapping->a_ops = &nova_aops_dax;
break;
case TYPE_MKDIR:
+ inode->i_op = &nova_dir_inode_operations;
inode->i_fop = &nova_dir_operations;
inode->i_mapping->a_ops = &nova_aops_dax;
set_nlink(inode, 2);
diff --git a/fs/nova/namei.c b/fs/nova/namei.c
new file mode 100644
index 0000000..8076f5b
--- /dev/null
+++ b/fs/nova/namei.c
@@ -0,0 +1,97 @@
+/*
+ * BRIEF DESCRIPTION
+ *
+ * Inode operations for directories.
+ *
+ * Copyright 2015-2016 Regents of the University of California,
+ * UCSD Non-Volatile Systems Lab, Andiry Xu <jix024@cs.ucsd.edu>
+ * Copyright 2012-2013 Intel Corporation
+ * Copyright 2009-2011 Marco Stornelli <marco.stornelli@gmail.com>
+ * Copyright 2003 Sony Corporation
+ * Copyright 2003 Matsushita Electric Industrial Co., Ltd.
+ * 2003-2004 (c) MontaVista Software, Inc. , Steve Longerbeam
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include "nova.h"
+#include "journal.h"
+#include "inode.h"
+
+static ino_t nova_inode_by_name(struct inode *dir, struct qstr *entry,
+ struct nova_dentry **res_entry)
+{
+ struct super_block *sb = dir->i_sb;
+ struct nova_dentry *direntry;
+
+ direntry = nova_find_dentry(sb, NULL, dir,
+ entry->name, entry->len);
+ if (direntry == NULL)
+ return 0;
+
+ *res_entry = direntry;
+ return direntry->ino;
+}
+
+static struct dentry *nova_lookup(struct inode *dir, struct dentry *dentry,
+ unsigned int flags)
+{
+ struct inode *inode = NULL;
+ struct nova_dentry *de;
+ ino_t ino;
+ timing_t lookup_time;
+
+ NOVA_START_TIMING(lookup_t, lookup_time);
+ if (dentry->d_name.len > NOVA_NAME_LEN) {
+ nova_dbg("%s: namelen %u exceeds limit\n",
+ __func__, dentry->d_name.len);
+ return ERR_PTR(-ENAMETOOLONG);
+ }
+
+ nova_dbg_verbose("%s: %s\n", __func__, dentry->d_name.name);
+ ino = nova_inode_by_name(dir, &dentry->d_name, &de);
+ nova_dbg_verbose("%s: ino %lu\n", __func__, ino);
+ if (ino) {
+ inode = nova_iget(dir->i_sb, ino);
+ if (inode == ERR_PTR(-ESTALE) || inode == ERR_PTR(-ENOMEM)
+ || inode == ERR_PTR(-EACCES)) {
+ nova_err(dir->i_sb,
+ "%s: get inode failed: %lu\n",
+ __func__, (unsigned long)ino);
+ return ERR_PTR(-EIO);
+ }
+ }
+
+ NOVA_END_TIMING(lookup_t, lookup_time);
+ return d_splice_alias(inode, dentry);
+}
+
+struct dentry *nova_get_parent(struct dentry *child)
+{
+ struct inode *inode;
+ struct qstr dotdot = QSTR_INIT("..", 2);
+ struct nova_dentry *de = NULL;
+ ino_t ino;
+
+ nova_inode_by_name(child->d_inode, &dotdot, &de);
+ if (!de)
+ return ERR_PTR(-ENOENT);
+
+ /* FIXME: can de->ino be avoided by using the return value of
+ * nova_inode_by_name()?
+ */
+ ino = le64_to_cpu(de->ino);
+
+ if (ino)
+ inode = nova_iget(child->d_inode->i_sb, ino);
+ else
+ return ERR_PTR(-ENOENT);
+
+ return d_obtain_alias(inode);
+}
+
+const struct inode_operations nova_dir_inode_operations = {
+ .lookup = nova_lookup,
+};
diff --git a/fs/nova/nova.h b/fs/nova/nova.h
index 983c6b2..03ea0bd 100644
--- a/fs/nova/nova.h
+++ b/fs/nova/nova.h
@@ -484,6 +484,10 @@ int nova_add_dentry(struct dentry *dentry, u64 ino, int inc_link,
int nova_remove_dentry(struct dentry *dentry, int dec_link,
struct nova_inode_update *update, u64 epoch_id);

+/* namei.c */
+extern const struct inode_operations nova_dir_inode_operations;
+extern struct dentry *nova_get_parent(struct dentry *child);
+
/* rebuild.c */
int nova_rebuild_dir_inode_tree(struct super_block *sb,
struct nova_inode *pi, u64 pi_addr,
--
2.7.4