/*
 *
 * This code is issued under the GNU General Public License.
 * See the file COPYING in this distribution
 *
 * 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/ext2/namei.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  Big-endian to little-endian byte-swapping/bitmaps by
 *        David S. Miller (davem@caip.rutgers.edu), 1995
 *  Directory entry file type support and forward compatibility hooks
 *      for B-tree directories by Theodore Ts'o (tytso@mit.edu), 1998
 * 
 *  Changes for use in OBDFS
 *  Copyright (c) 1999, Seagate Technology Inc.
 *  Copyright (C) 2001, Cluster File Systems, Inc.
 *                       Rewritten based on recent ext2 page cache use.
 * 
 */

#include <linux/fs.h>
#include <linux/locks.h>
#include <linux/quotaops.h>

#define DEBUG_SUBSYSTEM S_LLITE

#include <linux/obd_support.h>
#include <linux/lustre_lite.h>
extern struct address_space_operations ll_aops;

/* from super.c */
extern void ll_change_inode(struct inode *inode);
extern int ll_setattr(struct dentry *de, struct iattr *attr);

/* from dir.c */
extern int ll_add_link (struct dentry *dentry, struct inode *inode);
ino_t ll_inode_by_name(struct inode * dir, struct dentry *dentry, int *typ);
int ext2_make_empty(struct inode *inode, struct inode *parent);
struct ext2_dir_entry_2 * ext2_find_entry (struct inode * dir,
                   struct dentry *dentry, struct page ** res_page);
int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page );
int ext2_empty_dir (struct inode * inode);
struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p);
void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de,
                   struct page *page, struct inode *inode);

/*
 * Couple of helper functions - make the code slightly cleaner.
 */
static inline void ext2_inc_count(struct inode *inode)
{
        inode->i_nlink++;
}

/* postpone the disk update until the inode really goes away */ 
static inline void ext2_dec_count(struct inode *inode)
{
        inode->i_nlink--;
}

static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
{
        int err;
        err = ll_add_link(dentry, inode);
        if (!err) {
                d_instantiate(dentry, inode);
                return 0;
        }
        ext2_dec_count(inode);
        iput(inode);
        return err;
}

/* methods */
static int ll_find_inode(struct inode *inode, unsigned long ino, void *opaque)
{
        struct mds_body *body = (struct mds_body *)opaque;

        if (inode->i_generation != body->generation)
                return 0;

        return 1;
}

static struct dentry *ll_lookup(struct inode * dir, struct dentry *dentry)
{
        struct ptlrpc_request *request = NULL;
        struct inode * inode = NULL;
        struct ll_sb_info *sbi = ll_i2sbi(dir);
        int err;
        int type;
        ino_t ino;
        
        ENTRY;
        if (dentry->d_name.len > EXT2_NAME_LEN)
                RETURN(ERR_PTR(-ENAMETOOLONG));

        ino = ll_inode_by_name(dir, dentry, &type);
        if (!ino)
                GOTO(negative, NULL);

        err = mdc_getattr(&sbi->ll_mds_client, sbi->ll_mds_conn, ino, type,
                          OBD_MD_FLNOTOBD|OBD_MD_FLBLOCKS, &request);
        if (err) {
                CERROR("failure %d inode %ld\n", err, ino);
                ptlrpc_free_req(request);
                RETURN(ERR_PTR(-abs(err)));
        }

        inode = iget4(dir->i_sb, ino, ll_find_inode,
                      lustre_msg_buf(request->rq_repmsg, 0));

        ptlrpc_free_req(request);
        if (!inode) 
                RETURN(ERR_PTR(-ENOMEM));

        EXIT;
 negative:
        d_add(dentry, inode);
        return NULL;
}

static struct inode *ll_create_node(struct inode *dir, const char *name, 
                                    int namelen, const char *tgt, int tgtlen, 
                                    int mode, __u64 id)
{
        struct inode *inode;
        struct ptlrpc_request *request = NULL;
        struct mds_body *body;
        int err;
        time_t time = CURRENT_TIME;
        struct ll_sb_info *sbi = ll_i2sbi(dir);

        ENTRY;

        err = mdc_create(&sbi->ll_mds_client, sbi->ll_mds_conn, dir, name,
                         namelen, tgt, tgtlen, mode, id,  current->uid,
                         current->gid, time, &request);
        if (err) { 
                inode = ERR_PTR(err);
                GOTO(out, err);
        }
        body = lustre_msg_buf(request->rq_repmsg, 0);
        body->valid = OBD_MD_FLNOTOBD;

        body->objid = id; 
        body->nlink = 1;
        body->atime = body->ctime = body->mtime = time;
        body->mode = mode;
        CDEBUG(D_INODE, "-- new_inode: objid %lld, ino %d, mode %o\n",
               body->objid, body->ino, body->mode); 

        inode = iget4(dir->i_sb, body->ino, ll_find_inode, body);
        if (IS_ERR(inode)) {
                CERROR("new_inode -fatal:  %ld\n", PTR_ERR(inode));
                inode = ERR_PTR(-EIO);
                LBUG();
                GOTO(out, -EIO);
        }

        if (!list_empty(&inode->i_dentry)) {
                CERROR("new_inode -fatal: inode %d, ct %d lnk %d\n", 
                       body->ino, atomic_read(&inode->i_count), 
                       inode->i_nlink);
                iput(inode);
                LBUG();
                inode = ERR_PTR(-EIO);
                GOTO(out, -EIO);
        }

        EXIT;
 out:
        ptlrpc_free_req(request);
        return inode;
} /* ll_new_inode */

int ll_mdc_unlink(struct inode *dir, struct inode *child,
                  const char *name, int len)
{
        struct ptlrpc_request *request = NULL;
        int err;
        struct ll_sb_info *sbi = ll_i2sbi(dir);

        ENTRY;

        err = mdc_unlink(&sbi->ll_mds_client, sbi->ll_mds_conn, dir, child,
                         name, len, &request);
        ptlrpc_free_req(request);

        EXIT;
        return err;
}

int ll_mdc_link(struct dentry *src, struct inode *dir, 
                const char *name, int len)
{
        struct ptlrpc_request *request = NULL;
        int err;
        struct ll_sb_info *sbi = ll_i2sbi(dir);

        ENTRY;

        err = mdc_link(&sbi->ll_mds_client, sbi->ll_mds_conn, src, dir, name,
                       len, &request);
        ptlrpc_free_req(request);

        EXIT;
        return err;
}

int ll_mdc_rename(struct inode *src, struct inode *tgt, 
                  struct dentry *old, struct dentry *new)
{
        struct ptlrpc_request *request = NULL;
        int err;
        struct ll_sb_info *sbi = ll_i2sbi(src);

        ENTRY;

        err = mdc_rename(&sbi->ll_mds_client, sbi->ll_mds_conn, src, tgt, 
                         old->d_name.name, old->d_name.len, 
                         new->d_name.name, new->d_name.len, &request);
        ptlrpc_free_req(request);

        EXIT;
        return err;
}

/*
 * 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 ll_create (struct inode * dir, struct dentry * dentry, int mode)
{
        int err; 
        struct obdo oa;
        struct inode * inode;

        memset(&oa, 0, sizeof(oa)); 
        oa.o_valid = OBD_MD_FLMODE; 
        oa.o_mode = S_IFREG | 0600;
        err = obd_create(ll_i2obdconn(dir), &oa);  
        if (err) { 
                EXIT; 
                return err;
        }

        mode = mode | S_IFREG;
        CDEBUG(D_DENTRY, "name %s mode %o o_id %lld\n", 
               dentry->d_name.name, mode, oa.o_id);
        inode = ll_create_node(dir, dentry->d_name.name, dentry->d_name.len, 
                               NULL, 0, mode, oa.o_id);
        err = PTR_ERR(inode);
        if (!IS_ERR(inode)) {
                // XXX clean up the object
                inode->i_op = &ll_file_inode_operations;
                inode->i_fop = &ll_file_operations;
                inode->i_mapping->a_ops = &ll_aops;
                err = ext2_add_nondir(dentry, inode);
        }
        EXIT;
        return err;
} /* ll_create */


static int ll_mknod (struct inode * dir, struct dentry *dentry, int mode, int rdev)
{
        struct inode * inode = ll_create_node(dir, dentry->d_name.name, 
                                              dentry->d_name.len, NULL, 0,
                                              mode, 0);
        int err = PTR_ERR(inode);
        if (!IS_ERR(inode)) {
                init_special_inode(inode, mode, rdev);
                err = ext2_add_nondir(dentry, inode);
        }
        return err;
}

static int ll_symlink (struct inode * dir, struct dentry * dentry,
        const char * symname)
{
        int err = -ENAMETOOLONG;
        unsigned l = strlen(symname);
        struct inode * inode;
        struct ll_inode_info *oinfo;

        if (l > LL_INLINESZ)
                return err;

        inode = ll_create_node(dir, dentry->d_name.name, 
                               dentry->d_name.len, symname, l,
                               S_IFLNK | S_IRWXUGO, 0);
        err = PTR_ERR(inode);
        if (IS_ERR(inode))
                return err;

        oinfo = ll_i2info(inode);
        
        inode->i_op = &ll_fast_symlink_inode_operations;
        memcpy(oinfo->lli_inline, symname, l);
        inode->i_size = l-1;

        err = ext2_add_nondir(dentry, inode);

        if (err) { 
                ext2_dec_count(inode);
                iput (inode);
        }
        return err;
}

static int ll_link (struct dentry * old_dentry, struct inode * dir,
        struct dentry *dentry)
{
        int err;
        struct inode *inode = old_dentry->d_inode;

        if (S_ISDIR(inode->i_mode))
                return -EPERM;

        if (inode->i_nlink >= EXT2_LINK_MAX)
                return -EMLINK;

        err = ll_mdc_link(old_dentry, dir, 
                          dentry->d_name.name, dentry->d_name.len);
        if (err) { 
                EXIT;
                return err;
        }

        inode->i_ctime = CURRENT_TIME;
        ext2_inc_count(inode);
        atomic_inc(&inode->i_count);

        return ext2_add_nondir(dentry, inode);
}


static int ll_mkdir(struct inode * dir, struct dentry * dentry, int mode)
{
        struct inode * inode;
        int err = -EMLINK;
        ENTRY;

        if (dir->i_nlink >= EXT2_LINK_MAX)
                goto out;

        ext2_inc_count(dir);

        inode = ll_create_node (dir, dentry->d_name.name, 
                                dentry->d_name.len, NULL, 0, 
                                S_IFDIR | mode, 0);
        err = PTR_ERR(inode);
        if (IS_ERR(inode))
                goto out_dir;

        inode->i_op = &ll_dir_inode_operations;
        inode->i_fop = &ll_dir_operations;
        inode->i_mapping->a_ops = &ll_aops;
        inode->i_nlink = 1;
        ext2_inc_count(inode);

        err = ext2_make_empty(inode, dir);
        if (err)
                goto out_fail;

        err = ll_add_link(dentry, inode);
        if (err)
                goto out_fail;

        d_instantiate(dentry, inode);
out:
        EXIT;
        return err;

out_fail:
        ext2_dec_count(inode);
        ext2_dec_count(inode);
        iput(inode);
        EXIT;
out_dir:
        ext2_dec_count(dir);
        EXIT;
        goto out;
}

static int ll_unlink(struct inode * dir, struct dentry *dentry)
{
        struct inode * inode = dentry->d_inode;
        struct ext2_dir_entry_2 * de;
        struct page * page;
        int err = -ENOENT;

        de = ext2_find_entry (dir, dentry, &page);
        if (!de)
                goto out;
        
        err = ll_mdc_unlink(dir, dentry->d_inode,
                            dentry->d_name.name, dentry->d_name.len);
        if (err) 
                goto out;

        err = ext2_delete_entry (de, page);
        if (err)
                goto out;

        inode->i_ctime = dir->i_ctime;
        ext2_dec_count(inode);
        err = 0;
out:
        return err;
}

static int ll_rmdir(struct inode * dir, struct dentry *dentry)
{
        struct inode * inode = dentry->d_inode;
        int err = -ENOTEMPTY;

        if (ext2_empty_dir(inode)) {
                err = ll_unlink(dir, dentry);
                if (!err) {
                        inode->i_size = 0;
                        ext2_dec_count(inode);
                        ext2_dec_count(dir);
                }
        }
        return err;
}

static int ll_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 ext2_dir_entry_2 * dir_de = NULL;
        struct page * old_page;
        struct ext2_dir_entry_2 * old_de;
        int err = -ENOENT;

        err = ll_mdc_rename(old_dir, new_dir, old_dentry, new_dentry); 
        if (err) 
                goto out;

        old_de = ext2_find_entry (old_dir, old_dentry, &old_page);
        if (!old_de)
                goto out;

        if (S_ISDIR(old_inode->i_mode)) {
                err = -EIO;
                dir_de = ext2_dotdot(old_inode, &dir_page);
                if (!dir_de)
                        goto out_old;
        }

        if (new_inode) {
                struct page *new_page;
                struct ext2_dir_entry_2 *new_de;

                err = -ENOTEMPTY;
                if (dir_de && !ext2_empty_dir (new_inode))
                        goto out_dir;

                err = -ENOENT;
                new_de = ext2_find_entry (new_dir, new_dentry, &new_page);
                if (!new_de)
                        goto out_dir;
                ext2_inc_count(old_inode);
                ext2_set_link(new_dir, new_de, new_page, old_inode);
                new_inode->i_ctime = CURRENT_TIME;
                if (dir_de)
                        new_inode->i_nlink--;
                ext2_dec_count(new_inode);
        } else {
                if (dir_de) {
                        err = -EMLINK;
                        if (new_dir->i_nlink >= EXT2_LINK_MAX)
                                goto out_dir;
                }
                ext2_inc_count(old_inode);
                err = ll_add_link(new_dentry, old_inode);
                if (err) {
                        ext2_dec_count(old_inode);
                        goto out_dir;
                }
                if (dir_de)
                        ext2_inc_count(new_dir);
        }

        ext2_delete_entry (old_de, old_page);
        ext2_dec_count(old_inode);

        if (dir_de) {
                ext2_set_link(old_inode, dir_de, dir_page, new_dir);
                ext2_dec_count(old_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;
}

struct inode_operations ll_dir_inode_operations = {
        create:         ll_create,
        lookup:         ll_lookup,
        link:           ll_link,
        unlink:         ll_unlink,
        symlink:        ll_symlink,
        mkdir:          ll_mkdir,
        rmdir:          ll_rmdir,
        mknod:          ll_mknod,
        rename:         ll_rename,
        setattr:        ll_setattr
};