/*
 *  dir.c
 *
 *  Copyright (C) 1995, 1996 by Paal-Kr. Engstad and Volker Lendecke
 *  Copyright (C) 1997 by Volker Lendecke
 *
 *  Please add a note about your changes to smbfs in the ChangeLog file.
 */

#include <linux/time.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/smp_lock.h>
#include <linux/ctype.h>
#include <linux/net.h>
#include <linux/sched.h>

#include <linux/smb_fs.h>
#include <linux/smb_mount.h>
#include <linux/smbno.h>

#include "smb_debug.h"
#include "proto.h"

static int smb_readdir(struct file *, void *, filldir_t);
static int smb_dir_open(struct inode *, struct file *);

static struct dentry *smb_lookup(struct inode *, struct dentry *, struct nameidata *);
static int smb_create(struct inode *, struct dentry *, int, struct nameidata *);
static int smb_mkdir(struct inode *, struct dentry *, int);
static int smb_rmdir(struct inode *, struct dentry *);
static int smb_unlink(struct inode *, struct dentry *);
static int smb_rename(struct inode *, struct dentry *,
                      struct inode *, struct dentry *);
static int smb_make_node(struct inode *,struct dentry *,int,dev_t);
static int smb_link(struct dentry *, struct inode *, struct dentry *);

const struct file_operations smb_dir_operations =
{
        .read           = generic_read_dir,
        .readdir        = smb_readdir,
        .ioctl          = smb_ioctl,
        .open           = smb_dir_open,
};

const struct inode_operations smb_dir_inode_operations =
{
        .create         = smb_create,
        .lookup         = smb_lookup,
        .unlink         = smb_unlink,
        .mkdir          = smb_mkdir,
        .rmdir          = smb_rmdir,
        .rename         = smb_rename,
        .getattr        = smb_getattr,
        .setattr        = smb_notify_change,
};

const struct inode_operations smb_dir_inode_operations_unix =
{
        .create         = smb_create,
        .lookup         = smb_lookup,
        .unlink         = smb_unlink,
        .mkdir          = smb_mkdir,
        .rmdir          = smb_rmdir,
        .rename         = smb_rename,
        .getattr        = smb_getattr,
        .setattr        = smb_notify_change,
        .symlink        = smb_symlink,
        .mknod          = smb_make_node,
        .link           = smb_link,
};

/*
 * Read a directory, using filldir to fill the dirent memory.
 * smb_proc_readdir does the actual reading from the smb server.
 *
 * The cache code is almost directly taken from ncpfs
 */
static int 
smb_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
        struct dentry *dentry = filp->f_path.dentry;
        struct inode *dir = dentry->d_inode;
        struct smb_sb_info *server = server_from_dentry(dentry);
        union  smb_dir_cache *cache = NULL;
        struct smb_cache_control ctl;
        struct page *page = NULL;
        int result;

        ctl.page  = NULL;
        ctl.cache = NULL;

        VERBOSE("reading %s/%s, f_pos=%d\n",
                DENTRY_PATH(dentry),  (int) filp->f_pos);

        result = 0;

        lock_kernel();

        switch ((unsigned int) filp->f_pos) {
        case 0:
                if (filldir(dirent, ".", 1, 0, dir->i_ino, DT_DIR) < 0)
                        goto out;
                filp->f_pos = 1;
                /* fallthrough */
        case 1:
                if (filldir(dirent, "..", 2, 1, parent_ino(dentry), DT_DIR) < 0)
                        goto out;
                filp->f_pos = 2;
        }

        /*
         * Make sure our inode is up-to-date.
         */
        result = smb_revalidate_inode(dentry);
        if (result)
                goto out;


        page = grab_cache_page(&dir->i_data, 0);
        if (!page)
                goto read_really;

        ctl.cache = cache = kmap(page);
        ctl.head  = cache->head;

        if (!PageUptodate(page) || !ctl.head.eof) {
                VERBOSE("%s/%s, page uptodate=%d, eof=%d\n",
                         DENTRY_PATH(dentry), PageUptodate(page),ctl.head.eof);
                goto init_cache;
        }

        if (filp->f_pos == 2) {
                if (jiffies - ctl.head.time >= SMB_MAX_AGE(server))
                        goto init_cache;

                /*
                 * N.B. ncpfs checks mtime of dentry too here, we don't.
                 *   1. common smb servers do not update mtime on dir changes
                 *   2. it requires an extra smb request
                 *      (revalidate has the same timeout as ctl.head.time)
                 *
                 * Instead smbfs invalidates its own cache on local changes
                 * and remote changes are not seen until timeout.
                 */
        }

        if (filp->f_pos > ctl.head.end)
                goto finished;

        ctl.fpos = filp->f_pos + (SMB_DIRCACHE_START - 2);
        ctl.ofs  = ctl.fpos / SMB_DIRCACHE_SIZE;
        ctl.idx  = ctl.fpos % SMB_DIRCACHE_SIZE;

        for (;;) {
                if (ctl.ofs != 0) {
                        ctl.page = find_lock_page(&dir->i_data, ctl.ofs);
                        if (!ctl.page)
                                goto invalid_cache;
                        ctl.cache = kmap(ctl.page);
                        if (!PageUptodate(ctl.page))
                                goto invalid_cache;
                }
                while (ctl.idx < SMB_DIRCACHE_SIZE) {
                        struct dentry *dent;
                        int res;

                        dent = smb_dget_fpos(ctl.cache->dentry[ctl.idx],
                                             dentry, filp->f_pos);
                        if (!dent)
                                goto invalid_cache;

                        res = filldir(dirent, dent->d_name.name,
                                      dent->d_name.len, filp->f_pos,
                                      dent->d_inode->i_ino, DT_UNKNOWN);
                        dput(dent);
                        if (res)
                                goto finished;
                        filp->f_pos += 1;
                        ctl.idx += 1;
                        if (filp->f_pos > ctl.head.end)
                                goto finished;
                }
                if (ctl.page) {
                        kunmap(ctl.page);
                        SetPageUptodate(ctl.page);
                        unlock_page(ctl.page);
                        page_cache_release(ctl.page);
                        ctl.page = NULL;
                }
                ctl.idx  = 0;
                ctl.ofs += 1;
        }
invalid_cache:
        if (ctl.page) {
                kunmap(ctl.page);
                unlock_page(ctl.page);
                page_cache_release(ctl.page);
                ctl.page = NULL;
        }
        ctl.cache = cache;
init_cache:
        smb_invalidate_dircache_entries(dentry);
        ctl.head.time = jiffies;
        ctl.head.eof = 0;
        ctl.fpos = 2;
        ctl.ofs = 0;
        ctl.idx = SMB_DIRCACHE_START;
        ctl.filled = 0;
        ctl.valid  = 1;
read_really:
        result = server->ops->readdir(filp, dirent, filldir, &ctl);
        if (result == -ERESTARTSYS && page)
                ClearPageUptodate(page);
        if (ctl.idx == -1)
                goto invalid_cache;     /* retry */
        ctl.head.end = ctl.fpos - 1;
        ctl.head.eof = ctl.valid;
finished:
        if (page) {
                cache->head = ctl.head;
                kunmap(page);
                if (result != -ERESTARTSYS)
                        SetPageUptodate(page);
                unlock_page(page);
                page_cache_release(page);
        }
        if (ctl.page) {
                kunmap(ctl.page);
                SetPageUptodate(ctl.page);
                unlock_page(ctl.page);
                page_cache_release(ctl.page);
        }
out:
        unlock_kernel();
        return result;
}

static int
smb_dir_open(struct inode *dir, struct file *file)
{
        struct dentry *dentry = file->f_path.dentry;
        struct smb_sb_info *server;
        int error = 0;

        VERBOSE("(%s/%s)\n", dentry->d_parent->d_name.name,
                file->f_path.dentry->d_name.name);

        /*
         * Directory timestamps in the core protocol aren't updated
         * when a file is added, so we give them a very short TTL.
         */
        lock_kernel();
        server = server_from_dentry(dentry);
        if (server->opt.protocol < SMB_PROTOCOL_LANMAN2) {
                unsigned long age = jiffies - SMB_I(dir)->oldmtime;
                if (age > 2*HZ)
                        smb_invalid_dir_cache(dir);
        }

        /*
         * Note: in order to allow the smbmount process to open the
         * mount point, we only revalidate if the connection is valid or
         * if the process is trying to access something other than the root.
         */
        if (server->state == CONN_VALID || !IS_ROOT(dentry))
                error = smb_revalidate_inode(dentry);
        unlock_kernel();
        return error;
}

/*
 * Dentry operations routines
 */
static int smb_lookup_validate(struct dentry *, struct nameidata *);
static int smb_hash_dentry(struct dentry *, struct qstr *);
static int smb_compare_dentry(struct dentry *, struct qstr *, struct qstr *);
static int smb_delete_dentry(struct dentry *);

static const struct dentry_operations smbfs_dentry_operations =
{
        .d_revalidate   = smb_lookup_validate,
        .d_hash         = smb_hash_dentry,
        .d_compare      = smb_compare_dentry,
        .d_delete       = smb_delete_dentry,
};

static const struct dentry_operations smbfs_dentry_operations_case =
{
        .d_revalidate   = smb_lookup_validate,
        .d_delete       = smb_delete_dentry,
};


/*
 * This is the callback when the dcache has a lookup hit.
 */
static int
smb_lookup_validate(struct dentry * dentry, struct nameidata *nd)
{
        struct smb_sb_info *server = server_from_dentry(dentry);
        struct inode * inode = dentry->d_inode;
        unsigned long age = jiffies - dentry->d_time;
        int valid;

        /*
         * The default validation is based on dentry age:
         * we believe in dentries for a few seconds.  (But each
         * successful server lookup renews the timestamp.)
         */
        valid = (age <= SMB_MAX_AGE(server));
#ifdef SMBFS_DEBUG_VERBOSE
        if (!valid)
                VERBOSE("%s/%s not valid, age=%lu\n", 
                        DENTRY_PATH(dentry), age);
#endif

        if (inode) {
                lock_kernel();
                if (is_bad_inode(inode)) {
                        PARANOIA("%s/%s has dud inode\n", DENTRY_PATH(dentry));
                        valid = 0;
                } else if (!valid)
                        valid = (smb_revalidate_inode(dentry) == 0);
                unlock_kernel();
        } else {
                /*
                 * What should we do for negative dentries?
                 */
        }
        return valid;
}

static int 
smb_hash_dentry(struct dentry *dir, struct qstr *this)
{
        unsigned long hash;
        int i;

        hash = init_name_hash();
        for (i=0; i < this->len ; i++)
                hash = partial_name_hash(tolower(this->name[i]), hash);
        this->hash = end_name_hash(hash);
  
        return 0;
}

static int
smb_compare_dentry(struct dentry *dir, struct qstr *a, struct qstr *b)
{
        int i, result = 1;

        if (a->len != b->len)
                goto out;
        for (i=0; i < a->len; i++) {
                if (tolower(a->name[i]) != tolower(b->name[i]))
                        goto out;
        }
        result = 0;
out:
        return result;
}

/*
 * This is the callback from dput() when d_count is going to 0.
 * We use this to unhash dentries with bad inodes.
 */
static int
smb_delete_dentry(struct dentry * dentry)
{
        if (dentry->d_inode) {
                if (is_bad_inode(dentry->d_inode)) {
                        PARANOIA("bad inode, unhashing %s/%s\n",
                                 DENTRY_PATH(dentry));
                        return 1;
                }
        } else {
                /* N.B. Unhash negative dentries? */
        }
        return 0;
}

/*
 * Initialize a new dentry
 */
void
smb_new_dentry(struct dentry *dentry)
{
        struct smb_sb_info *server = server_from_dentry(dentry);

        if (server->mnt->flags & SMB_MOUNT_CASE)
                dentry->d_op = &smbfs_dentry_operations_case;
        else
                dentry->d_op = &smbfs_dentry_operations;
        dentry->d_time = jiffies;
}


/*
 * Whenever a lookup succeeds, we know the parent directories
 * are all valid, so we want to update the dentry timestamps.
 * N.B. Move this to dcache?
 */
void
smb_renew_times(struct dentry * dentry)
{
        dget(dentry);
        spin_lock(&dentry->d_lock);
        for (;;) {
                struct dentry *parent;

                dentry->d_time = jiffies;
                if (IS_ROOT(dentry))
                        break;
                parent = dentry->d_parent;
                dget(parent);
                spin_unlock(&dentry->d_lock);
                dput(dentry);
                dentry = parent;
                spin_lock(&dentry->d_lock);
        }
        spin_unlock(&dentry->d_lock);
        dput(dentry);
}

static struct dentry *
smb_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
{
        struct smb_fattr finfo;
        struct inode *inode;
        int error;
        struct smb_sb_info *server;

        error = -ENAMETOOLONG;
        if (dentry->d_name.len > SMB_MAXNAMELEN)
                goto out;

        /* Do not allow lookup of names with backslashes in */
        error = -EINVAL;
        if (memchr(dentry->d_name.name, '\\', dentry->d_name.len))
                goto out;

        lock_kernel();
        error = smb_proc_getattr(dentry, &finfo);
#ifdef SMBFS_PARANOIA
        if (error && error != -ENOENT)
                PARANOIA("find %s/%s failed, error=%d\n",
                         DENTRY_PATH(dentry), error);
#endif

        inode = NULL;
        if (error == -ENOENT)
                goto add_entry;
        if (!error) {
                error = -EACCES;
                finfo.f_ino = iunique(dentry->d_sb, 2);
                inode = smb_iget(dir->i_sb, &finfo);
                if (inode) {
        add_entry:
                        server = server_from_dentry(dentry);
                        if (server->mnt->flags & SMB_MOUNT_CASE)
                                dentry->d_op = &smbfs_dentry_operations_case;
                        else
                                dentry->d_op = &smbfs_dentry_operations;

                        d_add(dentry, inode);
                        smb_renew_times(dentry);
                        error = 0;
                }
        }
        unlock_kernel();
out:
        return ERR_PTR(error);
}

/*
 * This code is common to all routines creating a new inode.
 */
static int
smb_instantiate(struct dentry *dentry, __u16 fileid, int have_id)
{
        struct smb_sb_info *server = server_from_dentry(dentry);
        struct inode *inode;
        int error;
        struct smb_fattr fattr;

        VERBOSE("file %s/%s, fileid=%u\n", DENTRY_PATH(dentry), fileid);

        error = smb_proc_getattr(dentry, &fattr);
        if (error)
                goto out_close;

        smb_renew_times(dentry);
        fattr.f_ino = iunique(dentry->d_sb, 2);
        inode = smb_iget(dentry->d_sb, &fattr);
        if (!inode)
                goto out_no_inode;

        if (have_id) {
                struct smb_inode_info *ei = SMB_I(inode);
                ei->fileid = fileid;
                ei->access = SMB_O_RDWR;
                ei->open = server->generation;
        }
        d_instantiate(dentry, inode);
out:
        return error;

out_no_inode:
        error = -EACCES;
out_close:
        if (have_id) {
                PARANOIA("%s/%s failed, error=%d, closing %u\n",
                         DENTRY_PATH(dentry), error, fileid);
                smb_close_fileid(dentry, fileid);
        }
        goto out;
}

/* N.B. How should the mode argument be used? */
static int
smb_create(struct inode *dir, struct dentry *dentry, int mode,
                struct nameidata *nd)
{
        struct smb_sb_info *server = server_from_dentry(dentry);
        __u16 fileid;
        int error;
        struct iattr attr;

        VERBOSE("creating %s/%s, mode=%d\n", DENTRY_PATH(dentry), mode);

        lock_kernel();
        smb_invalid_dir_cache(dir);
        error = smb_proc_create(dentry, 0, get_seconds(), &fileid);
        if (!error) {
                if (server->opt.capabilities & SMB_CAP_UNIX) {
                        /* Set attributes for new file */
                        attr.ia_valid = ATTR_MODE;
                        attr.ia_mode = mode;
                        error = smb_proc_setattr_unix(dentry, &attr, 0, 0);
                }
                error = smb_instantiate(dentry, fileid, 1);
        } else {
                PARANOIA("%s/%s failed, error=%d\n",
                         DENTRY_PATH(dentry), error);
        }
        unlock_kernel();
        return error;
}

/* N.B. How should the mode argument be used? */
static int
smb_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
        struct smb_sb_info *server = server_from_dentry(dentry);
        int error;
        struct iattr attr;

        lock_kernel();
        smb_invalid_dir_cache(dir);
        error = smb_proc_mkdir(dentry);
        if (!error) {
                if (server->opt.capabilities & SMB_CAP_UNIX) {
                        /* Set attributes for new directory */
                        attr.ia_valid = ATTR_MODE;
                        attr.ia_mode = mode;
                        error = smb_proc_setattr_unix(dentry, &attr, 0, 0);
                }
                error = smb_instantiate(dentry, 0, 0);
        }
        unlock_kernel();
        return error;
}

static int
smb_rmdir(struct inode *dir, struct dentry *dentry)
{
        struct inode *inode = dentry->d_inode;
        int error;

        /*
         * Close the directory if it's open.
         */
        lock_kernel();
        smb_close(inode);

        /*
         * Check that nobody else is using the directory..
         */
        error = -EBUSY;
        if (!d_unhashed(dentry))
                goto out;

        smb_invalid_dir_cache(dir);
        error = smb_proc_rmdir(dentry);

out:
        unlock_kernel();
        return error;
}

static int
smb_unlink(struct inode *dir, struct dentry *dentry)
{
        int error;

        /*
         * Close the file if it's open.
         */
        lock_kernel();
        smb_close(dentry->d_inode);

        smb_invalid_dir_cache(dir);
        error = smb_proc_unlink(dentry);
        if (!error)
                smb_renew_times(dentry);
        unlock_kernel();
        return error;
}

static int
smb_rename(struct inode *old_dir, struct dentry *old_dentry,
           struct inode *new_dir, struct dentry *new_dentry)
{
        int error;

        /*
         * Close any open files, and check whether to delete the
         * target before attempting the rename.
         */
        lock_kernel();
        if (old_dentry->d_inode)
                smb_close(old_dentry->d_inode);
        if (new_dentry->d_inode) {
                smb_close(new_dentry->d_inode);
                error = smb_proc_unlink(new_dentry);
                if (error) {
                        VERBOSE("unlink %s/%s, error=%d\n",
                                DENTRY_PATH(new_dentry), error);
                        goto out;
                }
                /* FIXME */
                d_delete(new_dentry);
        }

        smb_invalid_dir_cache(old_dir);
        smb_invalid_dir_cache(new_dir);
        error = smb_proc_mv(old_dentry, new_dentry);
        if (!error) {
                smb_renew_times(old_dentry);
                smb_renew_times(new_dentry);
        }
out:
        unlock_kernel();
        return error;
}

/*
 * FIXME: samba servers won't let you create device nodes unless uid/gid
 * matches the connection credentials (and we don't know which those are ...)
 */
static int
smb_make_node(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
{
        int error;
        struct iattr attr;

        attr.ia_valid = ATTR_MODE | ATTR_UID | ATTR_GID;
        attr.ia_mode = mode;
        current_euid_egid(&attr.ia_uid, &attr.ia_gid);

        if (!new_valid_dev(dev))
                return -EINVAL;

        smb_invalid_dir_cache(dir);
        error = smb_proc_setattr_unix(dentry, &attr, MAJOR(dev), MINOR(dev));
        if (!error) {
                error = smb_instantiate(dentry, 0, 0);
        }
        return error;
}

/*
 * dentry = existing file
 * new_dentry = new file
 */
static int
smb_link(struct dentry *dentry, struct inode *dir, struct dentry *new_dentry)
{
        int error;

        DEBUG1("smb_link old=%s/%s new=%s/%s\n",
               DENTRY_PATH(dentry), DENTRY_PATH(new_dentry));
        smb_invalid_dir_cache(dir);
        error = smb_proc_link(server_from_dentry(dentry), dentry, new_dentry);
        if (!error) {
                smb_renew_times(dentry);
                error = smb_instantiate(new_dentry, 0, 0);
        }
        return error;
}