/*
 * (C) 2001 Clemson University and The University of Chicago
 *
 * See COPYING in top-level directory.
 */

/*
 *  Linux VFS inode operations.
 */

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

static int read_one_page(struct page *page)
{
        int ret;
        int max_block;
        ssize_t bytes_read = 0;
        struct inode *inode = page->mapping->host;
        const __u32 blocksize = PAGE_SIZE;      /* inode->i_blksize */
        const __u32 blockbits = PAGE_SHIFT;     /* inode->i_blkbits */
        struct iov_iter to;
        struct bio_vec bv = {.bv_page = page, .bv_len = PAGE_SIZE};

        iov_iter_bvec(&to, ITER_BVEC | READ, &bv, 1, PAGE_SIZE);

        gossip_debug(GOSSIP_INODE_DEBUG,
                    "orangefs_readpage called with page %p\n",
                     page);

        max_block = ((inode->i_size / blocksize) + 1);

        if (page->index < max_block) {
                loff_t blockptr_offset = (((loff_t) page->index) << blockbits);

                bytes_read = orangefs_inode_read(inode,
                                                 &to,
                                                 &blockptr_offset,
                                                 inode->i_size);
        }
        /* this will only zero remaining unread portions of the page data */
        iov_iter_zero(~0U, &to);
        /* takes care of potential aliasing */
        flush_dcache_page(page);
        if (bytes_read < 0) {
                ret = bytes_read;
                SetPageError(page);
        } else {
                SetPageUptodate(page);
                if (PageError(page))
                        ClearPageError(page);
                ret = 0;
        }
        /* unlock the page after the ->readpage() routine completes */
        unlock_page(page);
        return ret;
}

static int orangefs_readpage(struct file *file, struct page *page)
{
        return read_one_page(page);
}

static int orangefs_readpages(struct file *file,
                           struct address_space *mapping,
                           struct list_head *pages,
                           unsigned nr_pages)
{
        int page_idx;
        int ret;

        gossip_debug(GOSSIP_INODE_DEBUG, "orangefs_readpages called\n");

        for (page_idx = 0; page_idx < nr_pages; page_idx++) {
                struct page *page;

                page = list_entry(pages->prev, struct page, lru);
                list_del(&page->lru);
                if (!add_to_page_cache(page,
                                       mapping,
                                       page->index,
                                       readahead_gfp_mask(mapping))) {
                        ret = read_one_page(page);
                        gossip_debug(GOSSIP_INODE_DEBUG,
                                "failure adding page to cache, read_one_page returned: %d\n",
                                ret);
              } else {
                        put_page(page);
              }
        }
        BUG_ON(!list_empty(pages));
        return 0;
}

static void orangefs_invalidatepage(struct page *page,
                                 unsigned int offset,
                                 unsigned int length)
{
        gossip_debug(GOSSIP_INODE_DEBUG,
                     "orangefs_invalidatepage called on page %p "
                     "(offset is %u)\n",
                     page,
                     offset);

        ClearPageUptodate(page);
        ClearPageMappedToDisk(page);
        return;

}

static int orangefs_releasepage(struct page *page, gfp_t foo)
{
        gossip_debug(GOSSIP_INODE_DEBUG,
                     "orangefs_releasepage called on page %p\n",
                     page);
        return 0;
}

/*
 * Having a direct_IO entry point in the address_space_operations
 * struct causes the kernel to allows us to use O_DIRECT on
 * open. Nothing will ever call this thing, but in the future we
 * will need to be able to use O_DIRECT on open in order to support
 * AIO. Modeled after NFS, they do this too.
 */

static ssize_t orangefs_direct_IO(struct kiocb *iocb,
                                  struct iov_iter *iter)
{
        gossip_debug(GOSSIP_INODE_DEBUG,
                     "orangefs_direct_IO: %s\n",
                     iocb->ki_filp->f_path.dentry->d_name.name);

        return -EINVAL;
}

struct backing_dev_info orangefs_backing_dev_info = {
        .name = "orangefs",
        .ra_pages = 0,
        .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
};

/** ORANGEFS2 implementation of address space operations */
const struct address_space_operations orangefs_address_operations = {
        .readpage = orangefs_readpage,
        .readpages = orangefs_readpages,
        .invalidatepage = orangefs_invalidatepage,
        .releasepage = orangefs_releasepage,
        .direct_IO = orangefs_direct_IO,
};

static int orangefs_setattr_size(struct inode *inode, struct iattr *iattr)
{
        struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
        struct orangefs_kernel_op_s *new_op;
        loff_t orig_size;
        int ret = -EINVAL;

        gossip_debug(GOSSIP_INODE_DEBUG,
                     "%s: %pU: Handle is %pU | fs_id %d | size is %llu\n",
                     __func__,
                     get_khandle_from_ino(inode),
                     &orangefs_inode->refn.khandle,
                     orangefs_inode->refn.fs_id,
                     iattr->ia_size);

        /* Ensure that we have a up to date size, so we know if it changed. */
        ret = orangefs_inode_getattr(inode, 0, 1);
        if (ret == -ESTALE)
                ret = -EIO;
        if (ret) {
                gossip_err("%s: orangefs_inode_getattr failed, ret:%d:.\n",
                    __func__, ret);
                return ret;
        }
        orig_size = i_size_read(inode);

        truncate_setsize(inode, iattr->ia_size);

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

        new_op->upcall.req.truncate.refn = orangefs_inode->refn;
        new_op->upcall.req.truncate.size = (__s64) iattr->ia_size;

        ret = service_operation(new_op, __func__,
                                get_interruptible_flag(inode));

        /*
         * the truncate has no downcall members to retrieve, but
         * the status value tells us if it went through ok or not
         */
        gossip_debug(GOSSIP_INODE_DEBUG,
                     "orangefs: orangefs_truncate got return value of %d\n",
                     ret);

        op_release(new_op);

        if (ret != 0)
                return ret;

        if (orig_size != i_size_read(inode))
                iattr->ia_valid |= ATTR_CTIME | ATTR_MTIME;

        return ret;
}

/*
 * Change attributes of an object referenced by dentry.
 */
int orangefs_setattr(struct dentry *dentry, struct iattr *iattr)
{
        int ret = -EINVAL;
        struct inode *inode = dentry->d_inode;

        gossip_debug(GOSSIP_INODE_DEBUG,
                     "orangefs_setattr: called on %s\n",
                     dentry->d_name.name);

        ret = inode_change_ok(inode, iattr);
        if (ret)
                goto out;

        if ((iattr->ia_valid & ATTR_SIZE) &&
            iattr->ia_size != i_size_read(inode)) {
                ret = orangefs_setattr_size(inode, iattr);
                if (ret)
                        goto out;
        }

        setattr_copy(inode, iattr);
        mark_inode_dirty(inode);

        ret = orangefs_inode_setattr(inode, iattr);
        gossip_debug(GOSSIP_INODE_DEBUG,
                     "orangefs_setattr: inode_setattr returned %d\n",
                     ret);

        if (!ret && (iattr->ia_valid & ATTR_MODE))
                /* change mod on a file that has ACLs */
                ret = posix_acl_chmod(inode, inode->i_mode);

out:
        gossip_debug(GOSSIP_INODE_DEBUG, "orangefs_setattr: returning %d\n", ret);
        return ret;
}

/*
 * Obtain attributes of an object given a dentry
 */
int orangefs_getattr(struct vfsmount *mnt,
                  struct dentry *dentry,
                  struct kstat *kstat)
{
        int ret = -ENOENT;
        struct inode *inode = dentry->d_inode;
        struct orangefs_inode_s *orangefs_inode = NULL;

        gossip_debug(GOSSIP_INODE_DEBUG,
                     "orangefs_getattr: called on %s\n",
                     dentry->d_name.name);

        ret = orangefs_inode_getattr(inode, 0, 0);
        if (ret == 0) {
                generic_fillattr(inode, kstat);

                /* override block size reported to stat */
                orangefs_inode = ORANGEFS_I(inode);
                kstat->blksize = orangefs_inode->blksize;
        }
        return ret;
}

int orangefs_permission(struct inode *inode, int mask)
{
        int ret;

        if (mask & MAY_NOT_BLOCK)
                return -ECHILD;

        gossip_debug(GOSSIP_INODE_DEBUG, "%s: refreshing\n", __func__);

        /* Make sure the permission (and other common attrs) are up to date. */
        ret = orangefs_inode_getattr(inode, 0, 0);
        if (ret < 0)
                return ret;

        return generic_permission(inode, mask);
}

/* ORANGEDS2 implementation of VFS inode operations for files */
const struct inode_operations orangefs_file_inode_operations = {
        .get_acl = orangefs_get_acl,
        .set_acl = orangefs_set_acl,
        .setattr = orangefs_setattr,
        .getattr = orangefs_getattr,
        .setxattr = generic_setxattr,
        .getxattr = generic_getxattr,
        .listxattr = orangefs_listxattr,
        .removexattr = generic_removexattr,
        .permission = orangefs_permission,
};

static int orangefs_init_iops(struct inode *inode)
{
        inode->i_mapping->a_ops = &orangefs_address_operations;

        switch (inode->i_mode & S_IFMT) {
        case S_IFREG:
                inode->i_op = &orangefs_file_inode_operations;
                inode->i_fop = &orangefs_file_operations;
                inode->i_blkbits = PAGE_SHIFT;
                break;
        case S_IFLNK:
                inode->i_op = &orangefs_symlink_inode_operations;
                break;
        case S_IFDIR:
                inode->i_op = &orangefs_dir_inode_operations;
                inode->i_fop = &orangefs_dir_operations;
                break;
        default:
                gossip_debug(GOSSIP_INODE_DEBUG,
                             "%s: unsupported mode\n",
                             __func__);
                return -EINVAL;
        }

        return 0;
}

/*
 * Given a ORANGEFS object identifier (fsid, handle), convert it into a ino_t type
 * that will be used as a hash-index from where the handle will
 * be searched for in the VFS hash table of inodes.
 */
static inline ino_t orangefs_handle_hash(struct orangefs_object_kref *ref)
{
        if (!ref)
                return 0;
        return orangefs_khandle_to_ino(&(ref->khandle));
}

/*
 * Called to set up an inode from iget5_locked.
 */
static int orangefs_set_inode(struct inode *inode, void *data)
{
        struct orangefs_object_kref *ref = (struct orangefs_object_kref *) data;
        ORANGEFS_I(inode)->refn.fs_id = ref->fs_id;
        ORANGEFS_I(inode)->refn.khandle = ref->khandle;
        return 0;
}

/*
 * Called to determine if handles match.
 */
static int orangefs_test_inode(struct inode *inode, void *data)
{
        struct orangefs_object_kref *ref = (struct orangefs_object_kref *) data;
        struct orangefs_inode_s *orangefs_inode = NULL;

        orangefs_inode = ORANGEFS_I(inode);
        return (!ORANGEFS_khandle_cmp(&(orangefs_inode->refn.khandle), &(ref->khandle))
                && orangefs_inode->refn.fs_id == ref->fs_id);
}

/*
 * Front-end to lookup the inode-cache maintained by the VFS using the ORANGEFS
 * file handle.
 *
 * @sb: the file system super block instance.
 * @ref: The ORANGEFS object for which we are trying to locate an inode structure.
 */
struct inode *orangefs_iget(struct super_block *sb, struct orangefs_object_kref *ref)
{
        struct inode *inode = NULL;
        unsigned long hash;
        int error;

        hash = orangefs_handle_hash(ref);
        inode = iget5_locked(sb, hash, orangefs_test_inode, orangefs_set_inode, ref);
        if (!inode || !(inode->i_state & I_NEW))
                return inode;

        error = orangefs_inode_getattr(inode, 1, 1);
        if (error) {
                iget_failed(inode);
                return ERR_PTR(error);
        }

        inode->i_ino = hash;    /* needed for stat etc */
        orangefs_init_iops(inode);
        unlock_new_inode(inode);

        gossip_debug(GOSSIP_INODE_DEBUG,
                     "iget handle %pU, fsid %d hash %ld i_ino %lu\n",
                     &ref->khandle,
                     ref->fs_id,
                     hash,
                     inode->i_ino);

        return inode;
}

/*
 * Allocate an inode for a newly created file and insert it into the inode hash.
 */
struct inode *orangefs_new_inode(struct super_block *sb, struct inode *dir,
                int mode, dev_t dev, struct orangefs_object_kref *ref)
{
        unsigned long hash = orangefs_handle_hash(ref);
        struct inode *inode;
        int error;

        gossip_debug(GOSSIP_INODE_DEBUG,
                     "%s:(sb is %p | MAJOR(dev)=%u | MINOR(dev)=%u mode=%o)\n",
                     __func__,
                     sb,
                     MAJOR(dev),
                     MINOR(dev),
                     mode);

        inode = new_inode(sb);
        if (!inode)
                return NULL;

        orangefs_set_inode(inode, ref);
        inode->i_ino = hash;    /* needed for stat etc */

        error = orangefs_inode_getattr(inode, 1, 1);
        if (error)
                goto out_iput;

        orangefs_init_iops(inode);

        inode->i_mode = mode;
        inode->i_uid = current_fsuid();
        inode->i_gid = current_fsgid();
        inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
        inode->i_size = PAGE_SIZE;
        inode->i_rdev = dev;

        error = insert_inode_locked4(inode, hash, orangefs_test_inode, ref);
        if (error < 0)
                goto out_iput;

        gossip_debug(GOSSIP_INODE_DEBUG,
                     "Initializing ACL's for inode %pU\n",
                     get_khandle_from_ino(inode));
        orangefs_init_acl(inode, dir);
        return inode;

out_iput:
        iput(inode);
        return ERR_PTR(error);
}