[PATCH 06/16] pramfs: inode operations for dirs

Marco Stornelli
2010-10-10T16:34:39Z

From: Marco Stornelli <marco.stornelli@gmail.com>

Inode operations for directories.

Signed-off-by: Marco Stornelli <marco.stornelli@gmail.com>
---
diff -Nurp linux-2.6.36-orig/fs/pramfs/namei.c linux-2.6.36/fs/pramfs/namei.c
--- linux-2.6.36-orig/fs/pramfs/namei.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6.36/fs/pramfs/namei.c 2010-09-18 12:00:35.000000000 +0200
@@ -0,0 +1,363 @@
+/*
+ * FILE NAME fs/pramfs/namei.c
+ *
+ * BRIEF DESCRIPTION
+ *
+ * Inode operations for directories.
+ *
+ * Copyright 2009-2010 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 "pram.h"
+#include "acl.h"
+#include "xattr.h"
+
+/*
+ * Couple of helper functions - make the code slightly cleaner.
+ */
+
+static inline void pram_inc_count(struct inode *inode)
+{
+ inode->i_nlink++;
+ pram_write_inode(inode, 0);
+}
+
+static inline void pram_dec_count(struct inode *inode)
+{
+ if (inode->i_nlink) {
+ inode->i_nlink--;
+ pram_write_inode(inode, 0);
+ }
+}
+
+static inline int pram_add_nondir(struct inode *dir,
+ struct dentry *dentry,
+ struct inode *inode)
+{
+ int err = pram_add_link(dentry, inode);
+ if (!err) {
+ d_instantiate(dentry, inode);
+ unlock_new_inode(inode);
+ return 0;
+ }
+ pram_dec_count(inode);
+ unlock_new_inode(inode);
+ iput(inode);
+ return err;
+}
+
+/*
+ * Methods themselves.
+ */
+
+static ino_t
+pram_inode_by_name(struct inode *dir,
+ struct dentry *dentry)
+{
+ struct pram_inode *pi;
+ ino_t ino;
+ int namelen;
+
+ pi = pram_get_inode(dir->i_sb, dir->i_ino);
+ ino = be64_to_cpu(pi->i_type.dir.head);
+
+ while (ino) {
+ pi = pram_get_inode(dir->i_sb, ino);
+
+ if (pi->i_links_count) {
+ namelen = strlen(pi->i_d.d_name);
+
+ if (namelen == dentry->d_name.len &&
+ !memcmp(dentry->d_name.name,
+ pi->i_d.d_name, namelen))
+ break;
+ }
+
+ ino = be64_to_cpu(pi->i_d.d_next);
+ }
+
+ return ino;
+}
+
+static struct dentry *
+pram_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
+{
+ struct inode *inode = NULL;
+ ino_t ino;
+
+ if (dentry->d_name.len > PRAM_NAME_LEN)
+ return ERR_PTR(-ENAMETOOLONG);
+
+ ino = pram_inode_by_name(dir, dentry);
+ if (ino) {
+ inode = pram_iget(dir->i_sb, ino);
+ if (!inode)
+ return ERR_PTR(-EACCES);
+ }
+
+ d_splice_alias(inode, dentry);
+ return NULL;
+}
+
+
+/*
+ * By the time this is called, we already have created
+ * the directory cache entry for the new file, but it
+ * is so far negative - it has no inode.
+ *
+ * If the create succeeds, we fill in the inode information
+ * with d_instantiate().
+ */
+static int pram_create(struct inode *dir, struct dentry *dentry,
+ int mode, struct nameidata *nd)
+{
+ struct inode *inode = pram_new_inode(dir, mode);
+ int err = PTR_ERR(inode);
+ if (!IS_ERR(inode)) {
+
+ inode->i_op = &pram_file_inode_operations;
+ inode->i_fop = &pram_file_operations;
+ inode->i_mapping->a_ops = &pram_aops;
+ err = pram_add_nondir(dir, dentry, inode);
+ }
+ return err;
+}
+
+static int pram_mknod(struct inode *dir, struct dentry *dentry, int mode,
+ dev_t rdev)
+{
+ struct inode *inode = pram_new_inode(dir, mode);
+ int err = PTR_ERR(inode);
+ if (!IS_ERR(inode)) {
+ init_special_inode(inode, mode, rdev);
+ pram_write_inode(inode, 0); /* update rdev */
+ err = pram_add_nondir(dir, dentry, inode);
+ }
+ return err;
+}
+
+static int pram_symlink(struct inode *dir,
+ struct dentry *dentry,
+ const char *symname)
+{
+ struct super_block *sb = dir->i_sb;
+ int err = -ENAMETOOLONG;
+ unsigned len = strlen(symname);
+ struct inode *inode;
+
+ if (len+1 > sb->s_blocksize)
+ goto out;
+
+ inode = pram_new_inode(dir, S_IFLNK | S_IRWXUGO);
+ err = PTR_ERR(inode);
+ if (IS_ERR(inode))
+ goto out;
+
+ inode->i_op = &pram_symlink_inode_operations;
+ inode->i_mapping->a_ops = &pram_aops;
+
+ err = pram_block_symlink(inode, symname, len);
+ if (err)
+ goto out_fail;
+
+ inode->i_size = len;
+ pram_write_inode(inode, 0);
+
+ err = pram_add_nondir(dir, dentry, inode);
+out:
+ return err;
+
+out_fail:
+ pram_dec_count(inode);
+ unlock_new_inode(inode);
+ iput(inode);
+ goto out;
+}
+
+static int pram_link(struct dentry *dest_dentry,
+ struct inode *dir,
+ struct dentry *dentry)
+{
+ pram_dbg("hard links not supported\n");
+ return -EOPNOTSUPP;
+}
+
+static int pram_unlink(struct inode *dir, struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+ inode->i_ctime = dir->i_ctime;
+ pram_dec_count(inode);
+ return 0;
+}
+
+static int pram_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+ struct inode *inode;
+ struct pram_inode *pi;
+ int err = -EMLINK;
+
+ if (dir->i_nlink >= PRAM_LINK_MAX)
+ goto out;
+
+ pram_inc_count(dir);
+
+ inode = pram_new_inode(dir, S_IFDIR | mode);
+ err = PTR_ERR(inode);
+ if (IS_ERR(inode))
+ goto out_dir;
+
+ inode->i_op = &pram_dir_inode_operations;
+ inode->i_fop = &pram_dir_operations;
+ inode->i_mapping->a_ops = &pram_aops;
+
+ pram_inc_count(inode);
+
+ /* make the new directory empty */
+ pi = pram_get_inode(dir->i_sb, inode->i_ino);
+ pram_memunlock_inode(pi);
+ pi->i_type.dir.head = pi->i_type.dir.tail = 0;
+ pram_memlock_inode(pi);
+
+ err = pram_add_link(dentry, inode);
+ if (err)
+ goto out_fail;
+
+ d_instantiate(dentry, inode);
+ unlock_new_inode(inode);
+out:
+ return err;
+
+out_fail:
+ pram_dec_count(inode);
+ pram_dec_count(inode);
+ unlock_new_inode(inode);
+ iput(inode);
+out_dir:
+ pram_dec_count(dir);
+ goto out;
+}
+
+static int pram_rmdir(struct inode *dir, struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+ struct pram_inode *pi;
+ int err = -ENOTEMPTY;
+
+ if (!inode)
+ return -ENOENT;
+
+ pi = pram_get_inode(dir->i_sb, inode->i_ino);
+
+ /* directory to delete is empty? */
+ if (pi->i_type.dir.tail == 0) {
+ inode->i_ctime = dir->i_ctime;
+ inode->i_size = 0;
+ inode->i_nlink = 0;
+ pram_write_inode(inode, 0);
+ pram_dec_count(dir);
+ err = 0;
+ } else {
+ pram_dbg("dir not empty\n");
+ }
+
+ return err;
+}
+
+static int pram_rename(struct inode *old_dir,
+ struct dentry *old_dentry,
+ struct inode *new_dir,
+ struct dentry *new_dentry)
+{
+ struct inode *old_inode = old_dentry->d_inode;
+ struct inode *new_inode = new_dentry->d_inode;
+ struct pram_inode *pi_new;
+ int err = -ENOENT;
+
+ if (new_inode) {
+ err = -ENOTEMPTY;
+ pi_new = pram_get_inode(new_dir->i_sb, new_inode->i_ino);
+ if (S_ISDIR(old_inode->i_mode)) {
+ if (pi_new->i_type.dir.tail != 0)
+ goto out;
+ if (new_inode->i_nlink)
+ new_inode->i_nlink--;
+ }
+
+ new_inode->i_ctime = CURRENT_TIME;
+ pram_dec_count(new_inode);
+ } else {
+ if (S_ISDIR(old_inode->i_mode)) {
+ err = -EMLINK;
+ if (new_dir->i_nlink >= PRAM_LINK_MAX)
+ goto out;
+ pram_dec_count(old_dir);
+ pram_inc_count(new_dir);
+ }
+ }
+
+ /* unlink the inode from the old directory ... */
+ err = pram_remove_link(old_inode);
+ if (err)
+ goto out;
+
+ /* and link it into the new directory. */
+ err = pram_add_link(new_dentry, old_inode);
+ if (err)
+ goto out;
+
+ err = 0;
+ out:
+ return err;
+}
+
+struct dentry *pram_get_parent(struct dentry *child)
+{
+ struct inode *inode;
+ struct pram_inode *pi, *piparent;
+ ino_t ino;
+
+ pi = pram_get_inode(child->d_inode->i_sb, child->d_inode->i_ino);
+ if (!pi)
+ return ERR_PTR(-EACCES);
+
+ piparent = pram_get_inode(child->d_inode->i_sb, be64_to_cpu(pi->i_d.d_parent));
+ if (!pi)
+ return ERR_PTR(-ENOENT);
+
+ ino = pram_get_inodenr(child->d_inode->i_sb, piparent);
+ if (ino) {
+ inode = pram_iget(child->d_inode->i_sb, ino);
+ if (!inode)
+ return ERR_PTR(-EACCES);
+ } else
+ return ERR_PTR(-ENOENT);
+
+ return d_obtain_alias(inode);
+}
+
+struct inode_operations pram_dir_inode_operations = {
+ .create = pram_create,
+ .lookup = pram_lookup,
+ .link = pram_link,
+ .unlink = pram_unlink,
+ .symlink = pram_symlink,
+ .mkdir = pram_mkdir,
+ .rmdir = pram_rmdir,
+ .mknod = pram_mknod,
+ .rename = pram_rename,
+#ifdef CONFIG_PRAMFS_XATTR
+ .setxattr = generic_setxattr,
+ .getxattr = generic_getxattr,
+ .listxattr = pram_listxattr,
+ .removexattr = generic_removexattr,
+#endif
+ .setattr = pram_notify_change,
+ .check_acl = pram_check_acl,
+};