// SPDX-License-Identifier: GPL-2.0
/*
 * (C) 2001 Clemson University and The University of Chicago
 *
 * See COPYING in top-level directory.
 */

#include "protocol.h"
#include "orangefs-kernel.h"
#include "orangefs-bufmap.h"

#include <linux/hashtable.h>
#include <linux/seq_file.h>

/* a cache for orangefs-inode objects (i.e. orangefs inode private data) */
static struct kmem_cache *orangefs_inode_cache;

/* list for storing orangefs specific superblocks in use */
LIST_HEAD(orangefs_superblocks);

DEFINE_SPINLOCK(orangefs_superblocks_lock);

enum {
        Opt_acl,
        Opt_intr,
        Opt_local_lock,
};

const struct fs_parameter_spec orangefs_fs_param_spec[] = {
        fsparam_flag    ("acl",                 Opt_acl),
        fsparam_flag    ("intr",                Opt_intr),
        fsparam_flag    ("local_lock",          Opt_local_lock),
        {}
};

uint64_t orangefs_features;

static int orangefs_show_options(struct seq_file *m, struct dentry *root)
{
        struct orangefs_sb_info_s *orangefs_sb = ORANGEFS_SB(root->d_sb);

        if (root->d_sb->s_flags & SB_POSIXACL)
                seq_puts(m, ",acl");
        if (orangefs_sb->flags & ORANGEFS_OPT_INTR)
                seq_puts(m, ",intr");
        if (orangefs_sb->flags & ORANGEFS_OPT_LOCAL_LOCK)
                seq_puts(m, ",local_lock");
        return 0;
}

static int orangefs_parse_param(struct fs_context *fc,
                struct fs_parameter *param)
{
        struct orangefs_sb_info_s *orangefs_sb = fc->s_fs_info;
        struct fs_parse_result result;
        int opt;

        opt = fs_parse(fc, orangefs_fs_param_spec, param, &result);
        if (opt < 0)
                return opt;

        switch (opt) {
        case Opt_acl:
                fc->sb_flags |= SB_POSIXACL;
                break;
        case Opt_intr:
                orangefs_sb->flags |= ORANGEFS_OPT_INTR;
                break;
        case Opt_local_lock:
                orangefs_sb->flags |= ORANGEFS_OPT_LOCAL_LOCK;
                break;
        }

        return 0;
}

static void orangefs_inode_cache_ctor(void *req)
{
        struct orangefs_inode_s *orangefs_inode = req;

        inode_init_once(&orangefs_inode->vfs_inode);
        init_rwsem(&orangefs_inode->xattr_sem);
}

static struct inode *orangefs_alloc_inode(struct super_block *sb)
{
        struct orangefs_inode_s *orangefs_inode;

        orangefs_inode = alloc_inode_sb(sb, orangefs_inode_cache, GFP_KERNEL);
        if (!orangefs_inode)
                return NULL;

        /*
         * We want to clear everything except for rw_semaphore and the
         * vfs_inode.
         */
        memset(&orangefs_inode->refn.khandle, 0, 16);
        orangefs_inode->refn.fs_id = ORANGEFS_FS_ID_NULL;
        orangefs_inode->last_failed_block_index_read = 0;
        memset(orangefs_inode->link_target, 0, sizeof(orangefs_inode->link_target));

        gossip_debug(GOSSIP_SUPER_DEBUG,
                     "orangefs_alloc_inode: allocated %p\n",
                     &orangefs_inode->vfs_inode);
        return &orangefs_inode->vfs_inode;
}

static void orangefs_free_inode(struct inode *inode)
{
        struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
        struct orangefs_cached_xattr *cx;
        struct hlist_node *tmp;
        int i;

        hash_for_each_safe(orangefs_inode->xattr_cache, i, tmp, cx, node) {
                hlist_del(&cx->node);
                kfree(cx);
        }

        kmem_cache_free(orangefs_inode_cache, orangefs_inode);
}

static void orangefs_destroy_inode(struct inode *inode)
{
        struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);

        gossip_debug(GOSSIP_SUPER_DEBUG,
                        "%s: deallocated %p destroying inode %pU\n",
                        __func__, orangefs_inode, get_khandle_from_ino(inode));
}

static int orangefs_write_inode(struct inode *inode,
                                struct writeback_control *wbc)
{
        gossip_debug(GOSSIP_SUPER_DEBUG, "orangefs_write_inode\n");
        return orangefs_inode_setattr(inode);
}

/*
 * NOTE: information filled in here is typically reflected in the
 * output of the system command 'df'
*/
static int orangefs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
        int ret = -ENOMEM;
        struct orangefs_kernel_op_s *new_op = NULL;
        int flags = 0;
        struct super_block *sb = NULL;

        sb = dentry->d_sb;

        gossip_debug(GOSSIP_SUPER_DEBUG,
                        "%s: called on sb %p (fs_id is %d)\n",
                        __func__,
                        sb,
                        (int)(ORANGEFS_SB(sb)->fs_id));

        new_op = op_alloc(ORANGEFS_VFS_OP_STATFS);
        if (!new_op)
                return ret;
        new_op->upcall.req.statfs.fs_id = ORANGEFS_SB(sb)->fs_id;

        if (ORANGEFS_SB(sb)->flags & ORANGEFS_OPT_INTR)
                flags = ORANGEFS_OP_INTERRUPTIBLE;

        ret = service_operation(new_op, "orangefs_statfs", flags);

        if (new_op->downcall.status < 0)
                goto out_op_release;

        gossip_debug(GOSSIP_SUPER_DEBUG,
                     "%s: got %ld blocks available | "
                     "%ld blocks total | %ld block size | "
                     "%ld files total | %ld files avail\n",
                     __func__,
                     (long)new_op->downcall.resp.statfs.blocks_avail,
                     (long)new_op->downcall.resp.statfs.blocks_total,
                     (long)new_op->downcall.resp.statfs.block_size,
                     (long)new_op->downcall.resp.statfs.files_total,
                     (long)new_op->downcall.resp.statfs.files_avail);

        buf->f_type = sb->s_magic;
        buf->f_fsid.val[0] = ORANGEFS_SB(sb)->fs_id;
        buf->f_fsid.val[1] = ORANGEFS_SB(sb)->id;
        buf->f_bsize = new_op->downcall.resp.statfs.block_size;
        buf->f_namelen = ORANGEFS_NAME_MAX;

        buf->f_blocks = (sector_t) new_op->downcall.resp.statfs.blocks_total;
        buf->f_bfree = (sector_t) new_op->downcall.resp.statfs.blocks_avail;
        buf->f_bavail = (sector_t) new_op->downcall.resp.statfs.blocks_avail;
        buf->f_files = (sector_t) new_op->downcall.resp.statfs.files_total;
        buf->f_ffree = (sector_t) new_op->downcall.resp.statfs.files_avail;
        buf->f_frsize = 0;

out_op_release:
        op_release(new_op);
        gossip_debug(GOSSIP_SUPER_DEBUG, "%s: returning %d\n", __func__, ret);
        return ret;
}

/*
 * Remount as initiated by VFS layer.  We just need to reparse the mount
 * options, no need to signal pvfs2-client-core about it.
 */
static int orangefs_reconfigure(struct fs_context *fc)
{
        struct super_block *sb = fc->root->d_sb;
        struct orangefs_sb_info_s *orangefs_sb = ORANGEFS_SB(sb);
        struct orangefs_sb_info_s *revised = fc->s_fs_info;
        unsigned int flags;

        flags = orangefs_sb->flags;
        flags &= ~(ORANGEFS_OPT_INTR | ORANGEFS_OPT_LOCAL_LOCK);
        flags |= revised->flags;
        WRITE_ONCE(orangefs_sb->flags, flags);

        gossip_debug(GOSSIP_SUPER_DEBUG, "orangefs_reconfigure: called\n");
        return 0;
}

/*
 * Remount as initiated by pvfs2-client-core on restart.  This is used to
 * repopulate mount information left from previous pvfs2-client-core.
 *
 * the idea here is that given a valid superblock, we're
 * re-initializing the user space client with the initial mount
 * information specified when the super block was first initialized.
 * this is very different than the first initialization/creation of a
 * superblock.  we use the special service_priority_operation to make
 * sure that the mount gets ahead of any other pending operation that
 * is waiting for servicing.  this means that the pvfs2-client won't
 * fail to start several times for all other pending operations before
 * the client regains all of the mount information from us.
 * NOTE: this function assumes that the request_mutex is already acquired!
 */
int orangefs_remount(struct orangefs_sb_info_s *orangefs_sb)
{
        struct orangefs_kernel_op_s *new_op;
        int ret = -EINVAL;

        gossip_debug(GOSSIP_SUPER_DEBUG, "orangefs_remount: called\n");

        new_op = op_alloc(ORANGEFS_VFS_OP_FS_MOUNT);
        if (!new_op)
                return -ENOMEM;
        strscpy(new_op->upcall.req.fs_mount.orangefs_config_server,
                orangefs_sb->devname);

        gossip_debug(GOSSIP_SUPER_DEBUG,
                     "Attempting ORANGEFS Remount via host %s\n",
                     new_op->upcall.req.fs_mount.orangefs_config_server);

        /*
         * we assume that the calling function has already acquired the
         * request_mutex to prevent other operations from bypassing
         * this one
         */
        ret = service_operation(new_op, "orangefs_remount",
                ORANGEFS_OP_PRIORITY | ORANGEFS_OP_NO_MUTEX);
        gossip_debug(GOSSIP_SUPER_DEBUG,
                     "orangefs_remount: mount got return value of %d\n",
                     ret);
        if (ret == 0) {
                /*
                 * store the id assigned to this sb -- it's just a
                 * short-lived mapping that the system interface uses
                 * to map this superblock to a particular mount entry
                 */
                orangefs_sb->id = new_op->downcall.resp.fs_mount.id;
                orangefs_sb->mount_pending = 0;
        }

        op_release(new_op);

        if (orangefs_userspace_version >= 20906) {
                new_op = op_alloc(ORANGEFS_VFS_OP_FEATURES);
                if (!new_op)
                        return -ENOMEM;
                new_op->upcall.req.features.features = 0;
                ret = service_operation(new_op, "orangefs_features",
                    ORANGEFS_OP_PRIORITY | ORANGEFS_OP_NO_MUTEX);
                if (!ret)
                        orangefs_features =
                            new_op->downcall.resp.features.features;
                else
                        orangefs_features = 0;
                op_release(new_op);
        } else {
                orangefs_features = 0;
        }

        return ret;
}

int fsid_key_table_initialize(void)
{
        return 0;
}

void fsid_key_table_finalize(void)
{
}

static const struct super_operations orangefs_s_ops = {
        .alloc_inode = orangefs_alloc_inode,
        .free_inode = orangefs_free_inode,
        .destroy_inode = orangefs_destroy_inode,
        .write_inode = orangefs_write_inode,
        .drop_inode = inode_just_drop,
        .statfs = orangefs_statfs,
        .show_options = orangefs_show_options,
};

static struct dentry *orangefs_fh_to_dentry(struct super_block *sb,
                                  struct fid *fid,
                                  int fh_len,
                                  int fh_type)
{
        struct orangefs_object_kref refn;

        if (fh_len < 5 || fh_type > 2)
                return NULL;

        ORANGEFS_khandle_from(&(refn.khandle), fid->raw, 16);
        refn.fs_id = (u32) fid->raw[4];
        gossip_debug(GOSSIP_SUPER_DEBUG,
                     "fh_to_dentry: handle %pU, fs_id %d\n",
                     &refn.khandle,
                     refn.fs_id);

        return d_obtain_alias(orangefs_iget(sb, &refn));
}

static int orangefs_encode_fh(struct inode *inode,
                    __u32 *fh,
                    int *max_len,
                    struct inode *parent)
{
        int len = parent ? 10 : 5;
        int type = 1;
        struct orangefs_object_kref refn;

        if (*max_len < len) {
                gossip_err("fh buffer is too small for encoding\n");
                *max_len = len;
                type = 255;
                goto out;
        }

        refn = ORANGEFS_I(inode)->refn;
        ORANGEFS_khandle_to(&refn.khandle, fh, 16);
        fh[4] = refn.fs_id;

        gossip_debug(GOSSIP_SUPER_DEBUG,
                     "Encoding fh: handle %pU, fsid %u\n",
                     &refn.khandle,
                     refn.fs_id);


        if (parent) {
                refn = ORANGEFS_I(parent)->refn;
                ORANGEFS_khandle_to(&refn.khandle, (char *) fh + 20, 16);
                fh[9] = refn.fs_id;

                type = 2;
                gossip_debug(GOSSIP_SUPER_DEBUG,
                             "Encoding parent: handle %pU, fsid %u\n",
                             &refn.khandle,
                             refn.fs_id);
        }
        *max_len = len;

out:
        return type;
}

static const struct export_operations orangefs_export_ops = {
        .encode_fh = orangefs_encode_fh,
        .fh_to_dentry = orangefs_fh_to_dentry,
};

static int orangefs_unmount(int id, __s32 fs_id, const char *devname)
{
        struct orangefs_kernel_op_s *op;
        int r;
        op = op_alloc(ORANGEFS_VFS_OP_FS_UMOUNT);
        if (!op)
                return -ENOMEM;
        op->upcall.req.fs_umount.id = id;
        op->upcall.req.fs_umount.fs_id = fs_id;
        strscpy(op->upcall.req.fs_umount.orangefs_config_server, devname);
        r = service_operation(op, "orangefs_fs_umount", 0);
        /* Not much to do about an error here. */
        if (r)
                gossip_err("orangefs_unmount: service_operation %d\n", r);
        op_release(op);
        return r;
}

static int orangefs_fill_sb(struct super_block *sb,
                            struct fs_context *fc,
                            struct orangefs_fs_mount_response *fs_mount)
{
        int ret;
        struct inode *root;
        struct dentry *root_dentry;
        struct orangefs_object_kref root_object;

        ORANGEFS_SB(sb)->sb = sb;

        ORANGEFS_SB(sb)->root_khandle = fs_mount->root_khandle;
        ORANGEFS_SB(sb)->fs_id = fs_mount->fs_id;
        ORANGEFS_SB(sb)->id = fs_mount->id;

        /* Hang the xattr handlers off the superblock */
        sb->s_xattr = orangefs_xattr_handlers;
        sb->s_magic = ORANGEFS_SUPER_MAGIC;
        sb->s_op = &orangefs_s_ops;
        set_default_d_op(sb, &orangefs_dentry_operations);

        sb->s_blocksize = PAGE_SIZE;
        sb->s_blocksize_bits = PAGE_SHIFT;
        sb->s_maxbytes = MAX_LFS_FILESIZE;

        ret = super_setup_bdi(sb);
        if (ret)
                return ret;

        root_object.khandle = ORANGEFS_SB(sb)->root_khandle;
        root_object.fs_id = ORANGEFS_SB(sb)->fs_id;
        gossip_debug(GOSSIP_SUPER_DEBUG,
                     "get inode %pU, fsid %d\n",
                     &root_object.khandle,
                     root_object.fs_id);

        root = orangefs_iget(sb, &root_object);
        if (IS_ERR(root))
                return PTR_ERR(root);

        gossip_debug(GOSSIP_SUPER_DEBUG,
                     "Allocated root inode [%p] with mode %x\n",
                     root,
                     root->i_mode);

        /* allocates and places root dentry in dcache */
        root_dentry = d_make_root(root);
        if (!root_dentry)
                return -ENOMEM;

        sb->s_export_op = &orangefs_export_ops;
        sb->s_root = root_dentry;
        return 0;
}

static int orangefs_get_tree(struct fs_context *fc)
{
        int ret;
        struct super_block *sb = ERR_PTR(-EINVAL);
        struct orangefs_kernel_op_s *new_op;

        if (!fc->source)
                return invalf(fc, "Device name not specified.\n");

        gossip_debug(GOSSIP_SUPER_DEBUG,
                     "orangefs_mount: called with devname %s\n",
                     fc->source);

        new_op = op_alloc(ORANGEFS_VFS_OP_FS_MOUNT);
        if (!new_op)
                return -ENOMEM;

        strscpy(new_op->upcall.req.fs_mount.orangefs_config_server, fc->source);

        gossip_debug(GOSSIP_SUPER_DEBUG,
                     "Attempting ORANGEFS Mount via host %s\n",
                     new_op->upcall.req.fs_mount.orangefs_config_server);

        ret = service_operation(new_op, "orangefs_mount", 0);
        gossip_debug(GOSSIP_SUPER_DEBUG,
                     "orangefs_mount: mount got return value of %d\n", ret);
        if (ret)
                goto free_op;

        if (new_op->downcall.resp.fs_mount.fs_id == ORANGEFS_FS_ID_NULL) {
                gossip_err("ERROR: Retrieved null fs_id\n");
                ret = -EINVAL;
                goto free_op;
        }

        sb = sget_fc(fc, NULL, set_anon_super_fc);

        if (IS_ERR(sb)) {
                ret = PTR_ERR(sb);
                orangefs_unmount(new_op->downcall.resp.fs_mount.id,
                                 new_op->downcall.resp.fs_mount.fs_id,
                                 fc->source);
                goto free_op;
        }

        /* init our private orangefs sb info */
        ret = orangefs_fill_sb(sb, fc, &new_op->downcall.resp.fs_mount);

        if (ret)
                goto free_sb_and_op;

        /*
         * on successful mount, store the devname and data
         * used
         */
        strscpy(ORANGEFS_SB(sb)->devname, fc->source);

        /* mount_pending must be cleared */
        ORANGEFS_SB(sb)->mount_pending = 0;

        /*
         * finally, add this sb to our list of known orangefs
         * sb's
         */
        gossip_debug(GOSSIP_SUPER_DEBUG,
                     "Adding SB %p to orangefs superblocks\n",
                     ORANGEFS_SB(sb));
        spin_lock(&orangefs_superblocks_lock);
        list_add_tail(&ORANGEFS_SB(sb)->list, &orangefs_superblocks);
        spin_unlock(&orangefs_superblocks_lock);
        op_release(new_op);

        /* Must be removed from the list now. */
        ORANGEFS_SB(sb)->no_list = 0;

        if (orangefs_userspace_version >= 20906) {
                new_op = op_alloc(ORANGEFS_VFS_OP_FEATURES);
                if (!new_op)
                        return -ENOMEM;
                new_op->upcall.req.features.features = 0;
                ret = service_operation(new_op, "orangefs_features", 0);
                orangefs_features = new_op->downcall.resp.features.features;
                op_release(new_op);
        } else {
                orangefs_features = 0;
        }

        fc->root = dget(sb->s_root);
        return 0;

free_sb_and_op:
        /* Will call orangefs_kill_sb with sb not in list. */
        ORANGEFS_SB(sb)->no_list = 1;
        /* ORANGEFS_VFS_OP_FS_UMOUNT is done by orangefs_kill_sb. */
        deactivate_locked_super(sb);
free_op:
        gossip_err("orangefs_mount: mount request failed with %d\n", ret);
        if (ret == -EINVAL) {
                gossip_err("Ensure that all orangefs-servers have the same FS configuration files\n");
                gossip_err("Look at pvfs2-client-core log file (typically /tmp/pvfs2-client.log) for more details\n");
        }

        op_release(new_op);

        return ret;
}

static void orangefs_free_fc(struct fs_context *fc)
{
        kfree(fc->s_fs_info);
}

static const struct fs_context_operations orangefs_context_ops = {
        .free           = orangefs_free_fc,
        .parse_param    = orangefs_parse_param,
        .get_tree       = orangefs_get_tree,
        .reconfigure    = orangefs_reconfigure,
};

/*
 * Set up the filesystem mount context.
 */
int orangefs_init_fs_context(struct fs_context *fc)
{
        struct orangefs_sb_info_s *osi;

        osi = kzalloc_obj(struct orangefs_sb_info_s);
        if (!osi)
                return -ENOMEM;

        /*
         * Force any potential flags that might be set from the mount
         * to zero, ie, initialize to unset.
         */
        fc->sb_flags_mask &= ~SB_POSIXACL;
        osi->flags &= ~ORANGEFS_OPT_INTR;
        osi->flags &= ~ORANGEFS_OPT_LOCAL_LOCK;

        fc->s_fs_info = osi;
        fc->ops = &orangefs_context_ops;
        return 0;
}

void orangefs_kill_sb(struct super_block *sb)
{
        int r;
        gossip_debug(GOSSIP_SUPER_DEBUG, "orangefs_kill_sb: called\n");

        /* provided sb cleanup */
        kill_anon_super(sb);

        if (!ORANGEFS_SB(sb)) {
                mutex_lock(&orangefs_request_mutex);
                mutex_unlock(&orangefs_request_mutex);
                return;
        }
        /*
         * issue the unmount to userspace to tell it to remove the
         * dynamic mount info it has for this superblock
         */
        r = orangefs_unmount(ORANGEFS_SB(sb)->id, ORANGEFS_SB(sb)->fs_id,
            ORANGEFS_SB(sb)->devname);
        if (!r)
                ORANGEFS_SB(sb)->mount_pending = 1;

        if (!ORANGEFS_SB(sb)->no_list) {
                /* remove the sb from our list of orangefs specific sb's */
                spin_lock(&orangefs_superblocks_lock);
                /* not list_del_init */
                __list_del_entry(&ORANGEFS_SB(sb)->list);
                ORANGEFS_SB(sb)->list.prev = NULL;
                spin_unlock(&orangefs_superblocks_lock);
        }

        /*
         * make sure that ORANGEFS_DEV_REMOUNT_ALL loop that might've seen us
         * gets completed before we free the dang thing.
         */
        mutex_lock(&orangefs_request_mutex);
        mutex_unlock(&orangefs_request_mutex);

        /* free the orangefs superblock private data */
        kfree(ORANGEFS_SB(sb));
}

int orangefs_inode_cache_initialize(void)
{
        orangefs_inode_cache = kmem_cache_create_usercopy(
                                        "orangefs_inode_cache",
                                        sizeof(struct orangefs_inode_s),
                                        0,
                                        0,
                                        offsetof(struct orangefs_inode_s,
                                                link_target),
                                        sizeof_field(struct orangefs_inode_s,
                                                link_target),
                                        orangefs_inode_cache_ctor);

        if (!orangefs_inode_cache) {
                gossip_err("Cannot create orangefs_inode_cache\n");
                return -ENOMEM;
        }
        return 0;
}

int orangefs_inode_cache_finalize(void)
{
        kmem_cache_destroy(orangefs_inode_cache);
        return 0;
}