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>

1 files changed, 342 insertions, 0 deletions

diff --git a/fs/exofs/namei.c b/fs/exofs/namei.c
new file mode 100644
index 000000000000..77fdd765e76d
--- /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,
+};