exofs: dir_inode and directory operations
implementation of directory and inode operations.
* A directory is treated as a file, and essentially contains a list
of <file name, inode #> pairs for files that are found in that
directory. The object IDs correspond to the files' inode numbers
and are allocated using a 64bit incrementing global counter.
* Each file's control block (AKA on-disk inode) is stored in its
object's attributes. This applies to both regular files and other
types (directories, device files, symlinks, etc.).
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
diff --git a/fs/exofs/namei.c b/fs/exofs/namei.c
new file mode 100644
index 0000000..77fdd76
--- /dev/null
+++ b/fs/exofs/namei.c
@@ -0,0 +1,342 @@
+/*
+ * Copyright (C) 2005, 2006
+ * Avishay Traeger (avishay@gmail.com) (avishay@il.ibm.com)
+ * Copyright (C) 2005, 2006
+ * International Business Machines
+ * Copyright (C) 2008, 2009
+ * Boaz Harrosh <bharrosh@panasas.com>
+ *
+ * Copyrights for code taken from ext2:
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ * from
+ * linux/fs/minix/inode.c
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation. Since it is based on ext2, and the only
+ * valid version of GPL for the Linux kernel is version 2, the only valid
+ * version of GPL for exofs is version 2.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "exofs.h"
+
+static inline int exofs_add_nondir(struct dentry *dentry, struct inode *inode)
+{
+ int err = exofs_add_link(dentry, inode);
+ if (!err) {
+ d_instantiate(dentry, inode);
+ return 0;
+ }
+ inode_dec_link_count(inode);
+ iput(inode);
+ return err;
+}
+
+static struct dentry *exofs_lookup(struct inode *dir, struct dentry *dentry,
+ struct nameidata *nd)
+{
+ struct inode *inode;
+ ino_t ino;
+
+ if (dentry->d_name.len > EXOFS_NAME_LEN)
+ return ERR_PTR(-ENAMETOOLONG);
+
+ ino = exofs_inode_by_name(dir, dentry);
+ inode = NULL;
+ if (ino) {
+ inode = exofs_iget(dir->i_sb, ino);
+ if (IS_ERR(inode))
+ return ERR_CAST(inode);
+ }
+ return d_splice_alias(inode, dentry);
+}
+
+static int exofs_create(struct inode *dir, struct dentry *dentry, int mode,
+ struct nameidata *nd)
+{
+ struct inode *inode = exofs_new_inode(dir, mode);
+ int err = PTR_ERR(inode);
+ if (!IS_ERR(inode)) {
+ inode->i_op = &exofs_file_inode_operations;
+ inode->i_fop = &exofs_file_operations;
+ inode->i_mapping->a_ops = &exofs_aops;
+ mark_inode_dirty(inode);
+ err = exofs_add_nondir(dentry, inode);
+ }
+ return err;
+}
+
+static int exofs_mknod(struct inode *dir, struct dentry *dentry, int mode,
+ dev_t rdev)
+{
+ struct inode *inode;
+ int err;
+
+ if (!new_valid_dev(rdev))
+ return -EINVAL;
+
+ inode = exofs_new_inode(dir, mode);
+ err = PTR_ERR(inode);
+ if (!IS_ERR(inode)) {
+ init_special_inode(inode, inode->i_mode, rdev);
+ mark_inode_dirty(inode);
+ err = exofs_add_nondir(dentry, inode);
+ }
+ return err;
+}
+
+static int exofs_symlink(struct inode *dir, struct dentry *dentry,
+ const char *symname)
+{
+ struct super_block *sb = dir->i_sb;
+ int err = -ENAMETOOLONG;
+ unsigned l = strlen(symname)+1;
+ struct inode *inode;
+ struct exofs_i_info *oi;
+
+ if (l > sb->s_blocksize)
+ goto out;
+
+ inode = exofs_new_inode(dir, S_IFLNK | S_IRWXUGO);
+ err = PTR_ERR(inode);
+ if (IS_ERR(inode))
+ goto out;
+
+ oi = exofs_i(inode);
+ if (l > sizeof(oi->i_data)) {
+ /* slow symlink */
+ inode->i_op = &exofs_symlink_inode_operations;
+ inode->i_mapping->a_ops = &exofs_aops;
+ memset(oi->i_data, 0, sizeof(oi->i_data));
+
+ err = page_symlink(inode, symname, l);
+ if (err)
+ goto out_fail;
+ } else {
+ /* fast symlink */
+ inode->i_op = &exofs_fast_symlink_inode_operations;
+ memcpy(oi->i_data, symname, l);
+ inode->i_size = l-1;
+ }
+ mark_inode_dirty(inode);
+
+ err = exofs_add_nondir(dentry, inode);
+out:
+ return err;
+
+out_fail:
+ inode_dec_link_count(inode);
+ iput(inode);
+ goto out;
+}
+
+static int exofs_link(struct dentry *old_dentry, struct inode *dir,
+ struct dentry *dentry)
+{
+ struct inode *inode = old_dentry->d_inode;
+
+ if (inode->i_nlink >= EXOFS_LINK_MAX)
+ return -EMLINK;
+
+ inode->i_ctime = CURRENT_TIME;
+ inode_inc_link_count(inode);
+ atomic_inc(&inode->i_count);
+
+ return exofs_add_nondir(dentry, inode);
+}
+
+static int exofs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+ struct inode *inode;
+ int err = -EMLINK;
+
+ if (dir->i_nlink >= EXOFS_LINK_MAX)
+ goto out;
+
+ inode_inc_link_count(dir);
+
+ inode = exofs_new_inode(dir, S_IFDIR | mode);
+ err = PTR_ERR(inode);
+ if (IS_ERR(inode))
+ goto out_dir;
+
+ inode->i_op = &exofs_dir_inode_operations;
+ inode->i_fop = &exofs_dir_operations;
+ inode->i_mapping->a_ops = &exofs_aops;
+
+ inode_inc_link_count(inode);
+
+ err = exofs_make_empty(inode, dir);
+ if (err)
+ goto out_fail;
+
+ err = exofs_add_link(dentry, inode);
+ if (err)
+ goto out_fail;
+
+ d_instantiate(dentry, inode);
+out:
+ return err;
+
+out_fail:
+ inode_dec_link_count(inode);
+ inode_dec_link_count(inode);
+ iput(inode);
+out_dir:
+ inode_dec_link_count(dir);
+ goto out;
+}
+
+static int exofs_unlink(struct inode *dir, struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+ struct exofs_dir_entry *de;
+ struct page *page;
+ int err = -ENOENT;
+
+ de = exofs_find_entry(dir, dentry, &page);
+ if (!de)
+ goto out;
+
+ err = exofs_delete_entry(de, page);
+ if (err)
+ goto out;
+
+ inode->i_ctime = dir->i_ctime;
+ inode_dec_link_count(inode);
+ err = 0;
+out:
+ return err;
+}
+
+static int exofs_rmdir(struct inode *dir, struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+ int err = -ENOTEMPTY;
+
+ if (exofs_empty_dir(inode)) {
+ err = exofs_unlink(dir, dentry);
+ if (!err) {
+ inode->i_size = 0;
+ inode_dec_link_count(inode);
+ inode_dec_link_count(dir);
+ }
+ }
+ return err;
+}
+
+static int exofs_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 page *dir_page = NULL;
+ struct exofs_dir_entry *dir_de = NULL;
+ struct page *old_page;
+ struct exofs_dir_entry *old_de;
+ int err = -ENOENT;
+
+ old_de = exofs_find_entry(old_dir, old_dentry, &old_page);
+ if (!old_de)
+ goto out;
+
+ if (S_ISDIR(old_inode->i_mode)) {
+ err = -EIO;
+ dir_de = exofs_dotdot(old_inode, &dir_page);
+ if (!dir_de)
+ goto out_old;
+ }
+
+ if (new_inode) {
+ struct page *new_page;
+ struct exofs_dir_entry *new_de;
+
+ err = -ENOTEMPTY;
+ if (dir_de && !exofs_empty_dir(new_inode))
+ goto out_dir;
+
+ err = -ENOENT;
+ new_de = exofs_find_entry(new_dir, new_dentry, &new_page);
+ if (!new_de)
+ goto out_dir;
+ inode_inc_link_count(old_inode);
+ err = exofs_set_link(new_dir, new_de, new_page, old_inode);
+ new_inode->i_ctime = CURRENT_TIME;
+ if (dir_de)
+ drop_nlink(new_inode);
+ inode_dec_link_count(new_inode);
+ if (err)
+ goto out_dir;
+ } else {
+ if (dir_de) {
+ err = -EMLINK;
+ if (new_dir->i_nlink >= EXOFS_LINK_MAX)
+ goto out_dir;
+ }
+ inode_inc_link_count(old_inode);
+ err = exofs_add_link(new_dentry, old_inode);
+ if (err) {
+ inode_dec_link_count(old_inode);
+ goto out_dir;
+ }
+ if (dir_de)
+ inode_inc_link_count(new_dir);
+ }
+
+ old_inode->i_ctime = CURRENT_TIME;
+
+ exofs_delete_entry(old_de, old_page);
+ inode_dec_link_count(old_inode);
+
+ if (dir_de) {
+ err = exofs_set_link(old_inode, dir_de, dir_page, new_dir);
+ inode_dec_link_count(old_dir);
+ if (err)
+ goto out_dir;
+ }
+ return 0;
+
+
+out_dir:
+ if (dir_de) {
+ kunmap(dir_page);
+ page_cache_release(dir_page);
+ }
+out_old:
+ kunmap(old_page);
+ page_cache_release(old_page);
+out:
+ return err;
+}
+
+const struct inode_operations exofs_dir_inode_operations = {
+ .create = exofs_create,
+ .lookup = exofs_lookup,
+ .link = exofs_link,
+ .unlink = exofs_unlink,
+ .symlink = exofs_symlink,
+ .mkdir = exofs_mkdir,
+ .rmdir = exofs_rmdir,
+ .mknod = exofs_mknod,
+ .rename = exofs_rename,
+ .setattr = exofs_setattr,
+};
+
+const struct inode_operations exofs_special_inode_operations = {
+ .setattr = exofs_setattr,
+};