// SPDX-License-Identifier: GPL-2.0
/*
 * (C) 2001 Clemson University and The University of Chicago
 * Copyright 2018 Omnibond Systems, L.L.C.
 *
 * See COPYING in top-level directory.
 */

/*
 *  Linux VFS inode operations.
 */

#include <linux/bvec.h>
#include "protocol.h"
#include "orangefs-kernel.h"
#include "orangefs-bufmap.h"

static int orangefs_writepage_locked(struct page *page,
    struct writeback_control *wbc)
{
        struct inode *inode = page->mapping->host;
        struct orangefs_write_range *wr = NULL;
        struct iov_iter iter;
        struct bio_vec bv;
        size_t len, wlen;
        ssize_t ret;
        loff_t off;

        set_page_writeback(page);

        len = i_size_read(inode);
        if (PagePrivate(page)) {
                wr = (struct orangefs_write_range *)page_private(page);
                WARN_ON(wr->pos >= len);
                off = wr->pos;
                if (off + wr->len > len)
                        wlen = len - off;
                else
                        wlen = wr->len;
        } else {
                WARN_ON(1);
                off = page_offset(page);
                if (off + PAGE_SIZE > len)
                        wlen = len - off;
                else
                        wlen = PAGE_SIZE;
        }
        /* Should've been handled in orangefs_invalidatepage. */
        WARN_ON(off == len || off + wlen > len);

        bv.bv_page = page;
        bv.bv_len = wlen;
        bv.bv_offset = off % PAGE_SIZE;
        WARN_ON(wlen == 0);
        iov_iter_bvec(&iter, WRITE, &bv, 1, wlen);

        ret = wait_for_direct_io(ORANGEFS_IO_WRITE, inode, &off, &iter, wlen,
            len, wr, NULL, NULL);
        if (ret < 0) {
                SetPageError(page);
                mapping_set_error(page->mapping, ret);
        } else {
                ret = 0;
        }
        kfree(detach_page_private(page));
        return ret;
}

static int orangefs_writepage(struct page *page, struct writeback_control *wbc)
{
        int ret;
        ret = orangefs_writepage_locked(page, wbc);
        unlock_page(page);
        end_page_writeback(page);
        return ret;
}

struct orangefs_writepages {
        loff_t off;
        size_t len;
        kuid_t uid;
        kgid_t gid;
        int maxpages;
        int npages;
        struct page **pages;
        struct bio_vec *bv;
};

static int orangefs_writepages_work(struct orangefs_writepages *ow,
    struct writeback_control *wbc)
{
        struct inode *inode = ow->pages[0]->mapping->host;
        struct orangefs_write_range *wrp, wr;
        struct iov_iter iter;
        ssize_t ret;
        size_t len;
        loff_t off;
        int i;

        len = i_size_read(inode);

        for (i = 0; i < ow->npages; i++) {
                set_page_writeback(ow->pages[i]);
                ow->bv[i].bv_page = ow->pages[i];
                ow->bv[i].bv_len = min(page_offset(ow->pages[i]) + PAGE_SIZE,
                    ow->off + ow->len) -
                    max(ow->off, page_offset(ow->pages[i]));
                if (i == 0)
                        ow->bv[i].bv_offset = ow->off -
                            page_offset(ow->pages[i]);
                else
                        ow->bv[i].bv_offset = 0;
        }
        iov_iter_bvec(&iter, WRITE, ow->bv, ow->npages, ow->len);

        WARN_ON(ow->off >= len);
        if (ow->off + ow->len > len)
                ow->len = len - ow->off;

        off = ow->off;
        wr.uid = ow->uid;
        wr.gid = ow->gid;
        ret = wait_for_direct_io(ORANGEFS_IO_WRITE, inode, &off, &iter, ow->len,
            0, &wr, NULL, NULL);
        if (ret < 0) {
                for (i = 0; i < ow->npages; i++) {
                        SetPageError(ow->pages[i]);
                        mapping_set_error(ow->pages[i]->mapping, ret);
                        if (PagePrivate(ow->pages[i])) {
                                wrp = (struct orangefs_write_range *)
                                    page_private(ow->pages[i]);
                                ClearPagePrivate(ow->pages[i]);
                                put_page(ow->pages[i]);
                                kfree(wrp);
                        }
                        end_page_writeback(ow->pages[i]);
                        unlock_page(ow->pages[i]);
                }
        } else {
                ret = 0;
                for (i = 0; i < ow->npages; i++) {
                        if (PagePrivate(ow->pages[i])) {
                                wrp = (struct orangefs_write_range *)
                                    page_private(ow->pages[i]);
                                ClearPagePrivate(ow->pages[i]);
                                put_page(ow->pages[i]);
                                kfree(wrp);
                        }
                        end_page_writeback(ow->pages[i]);
                        unlock_page(ow->pages[i]);
                }
        }
        return ret;
}

static int orangefs_writepages_callback(struct page *page,
    struct writeback_control *wbc, void *data)
{
        struct orangefs_writepages *ow = data;
        struct orangefs_write_range *wr;
        int ret;

        if (!PagePrivate(page)) {
                unlock_page(page);
                /* It's not private so there's nothing to write, right? */
                printk("writepages_callback not private!\n");
                BUG();
                return 0;
        }
        wr = (struct orangefs_write_range *)page_private(page);

        ret = -1;
        if (ow->npages == 0) {
                ow->off = wr->pos;
                ow->len = wr->len;
                ow->uid = wr->uid;
                ow->gid = wr->gid;
                ow->pages[ow->npages++] = page;
                ret = 0;
                goto done;
        }
        if (!uid_eq(ow->uid, wr->uid) || !gid_eq(ow->gid, wr->gid)) {
                orangefs_writepages_work(ow, wbc);
                ow->npages = 0;
                ret = -1;
                goto done;
        }
        if (ow->off + ow->len == wr->pos) {
                ow->len += wr->len;
                ow->pages[ow->npages++] = page;
                ret = 0;
                goto done;
        }
done:
        if (ret == -1) {
                if (ow->npages) {
                        orangefs_writepages_work(ow, wbc);
                        ow->npages = 0;
                }
                ret = orangefs_writepage_locked(page, wbc);
                mapping_set_error(page->mapping, ret);
                unlock_page(page);
                end_page_writeback(page);
        } else {
                if (ow->npages == ow->maxpages) {
                        orangefs_writepages_work(ow, wbc);
                        ow->npages = 0;
                }
        }
        return ret;
}

static int orangefs_writepages(struct address_space *mapping,
    struct writeback_control *wbc)
{
        struct orangefs_writepages *ow;
        struct blk_plug plug;
        int ret;
        ow = kzalloc(sizeof(struct orangefs_writepages), GFP_KERNEL);
        if (!ow)
                return -ENOMEM;
        ow->maxpages = orangefs_bufmap_size_query()/PAGE_SIZE;
        ow->pages = kcalloc(ow->maxpages, sizeof(struct page *), GFP_KERNEL);
        if (!ow->pages) {
                kfree(ow);
                return -ENOMEM;
        }
        ow->bv = kcalloc(ow->maxpages, sizeof(struct bio_vec), GFP_KERNEL);
        if (!ow->bv) {
                kfree(ow->pages);
                kfree(ow);
                return -ENOMEM;
        }
        blk_start_plug(&plug);
        ret = write_cache_pages(mapping, wbc, orangefs_writepages_callback, ow);
        if (ow->npages)
                ret = orangefs_writepages_work(ow, wbc);
        blk_finish_plug(&plug);
        kfree(ow->pages);
        kfree(ow->bv);
        kfree(ow);
        return ret;
}

static int orangefs_launder_page(struct page *);

static int orangefs_readpage(struct file *file, struct page *page)
{
        struct inode *inode = page->mapping->host;
        struct iov_iter iter;
        struct bio_vec bv;
        ssize_t ret;
        loff_t off; /* offset into this page */
        pgoff_t index; /* which page */
        struct page *next_page;
        char *kaddr;
        loff_t read_size;
        int buffer_index = -1; /* orangefs shared memory slot */
        int slot_index;   /* index into slot */
        int remaining;

        /*
         * Get up to this many bytes from Orangefs at a time and try
         * to fill them into the page cache at once. Tests with dd made
         * this seem like a reasonable static number, if there was
         * interest perhaps this number could be made setable through
         * sysfs...
         */
        read_size = 524288;

        if (PageDirty(page))
                orangefs_launder_page(page);

        off = page_offset(page);
        index = off >> PAGE_SHIFT;
        bv.bv_page = page;
        bv.bv_len = PAGE_SIZE;
        bv.bv_offset = 0;
        iov_iter_bvec(&iter, READ, &bv, 1, PAGE_SIZE);

        ret = wait_for_direct_io(ORANGEFS_IO_READ, inode, &off, &iter,
            read_size, inode->i_size, NULL, &buffer_index, file);
        remaining = ret;
        /* this will only zero remaining unread portions of the page data */
        iov_iter_zero(~0U, &iter);
        /* takes care of potential aliasing */
        flush_dcache_page(page);
        if (ret < 0) {
                SetPageError(page);
                unlock_page(page);
                goto out;
        } else {
                SetPageUptodate(page);
                if (PageError(page))
                        ClearPageError(page);
                ret = 0;
        }
        /* unlock the page after the ->readpage() routine completes */
        unlock_page(page);

        if (remaining > PAGE_SIZE) {
                slot_index = 0;
                while ((remaining - PAGE_SIZE) >= PAGE_SIZE) {
                        remaining -= PAGE_SIZE;
                        /*
                         * It is an optimization to try and fill more than one
                         * page... by now we've already gotten the single
                         * page we were after, if stuff doesn't seem to
                         * be going our way at this point just return
                         * and hope for the best.
                         *
                         * If we look for pages and they're already there is
                         * one reason to give up, and if they're not there
                         * and we can't create them is another reason.
                         */

                        index++;
                        slot_index++;
                        next_page = find_get_page(inode->i_mapping, index);
                        if (next_page) {
                                gossip_debug(GOSSIP_FILE_DEBUG,
                                        "%s: found next page, quitting\n",
                                        __func__);
                                put_page(next_page);
                                goto out;
                        }
                        next_page = find_or_create_page(inode->i_mapping,
                                                        index,
                                                        GFP_KERNEL);
                        /*
                         * I've never hit this, leave it as a printk for
                         * now so it will be obvious.
                         */
                        if (!next_page) {
                                printk("%s: can't create next page, quitting\n",
                                        __func__);
                                goto out;
                        }
                        kaddr = kmap_atomic(next_page);
                        orangefs_bufmap_page_fill(kaddr,
                                                buffer_index,
                                                slot_index);
                        kunmap_atomic(kaddr);
                        SetPageUptodate(next_page);
                        unlock_page(next_page);
                        put_page(next_page);
                }
        }

out:
        if (buffer_index != -1)
                orangefs_bufmap_put(buffer_index);
        return ret;
}

static int orangefs_write_begin(struct file *file,
    struct address_space *mapping,
    loff_t pos, unsigned len, unsigned flags, struct page **pagep,
    void **fsdata)
{
        struct orangefs_write_range *wr;
        struct page *page;
        pgoff_t index;
        int ret;

        index = pos >> PAGE_SHIFT;

        page = grab_cache_page_write_begin(mapping, index, flags);
        if (!page)
                return -ENOMEM;

        *pagep = page;

        if (PageDirty(page) && !PagePrivate(page)) {
                /*
                 * Should be impossible.  If it happens, launder the page
                 * since we don't know what's dirty.  This will WARN in
                 * orangefs_writepage_locked.
                 */
                ret = orangefs_launder_page(page);
                if (ret)
                        return ret;
        }
        if (PagePrivate(page)) {
                struct orangefs_write_range *wr;
                wr = (struct orangefs_write_range *)page_private(page);
                if (wr->pos + wr->len == pos &&
                    uid_eq(wr->uid, current_fsuid()) &&
                    gid_eq(wr->gid, current_fsgid())) {
                        wr->len += len;
                        goto okay;
                } else {
                        ret = orangefs_launder_page(page);
                        if (ret)
                                return ret;
                }
        }

        wr = kmalloc(sizeof *wr, GFP_KERNEL);
        if (!wr)
                return -ENOMEM;

        wr->pos = pos;
        wr->len = len;
        wr->uid = current_fsuid();
        wr->gid = current_fsgid();
        attach_page_private(page, wr);
okay:
        return 0;
}

static int orangefs_write_end(struct file *file, struct address_space *mapping,
    loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata)
{
        struct inode *inode = page->mapping->host;
        loff_t last_pos = pos + copied;

        /*
         * No need to use i_size_read() here, the i_size
         * cannot change under us because we hold the i_mutex.
         */
        if (last_pos > inode->i_size)
                i_size_write(inode, last_pos);

        /* zero the stale part of the page if we did a short copy */
        if (!PageUptodate(page)) {
                unsigned from = pos & (PAGE_SIZE - 1);
                if (copied < len) {
                        zero_user(page, from + copied, len - copied);
                }
                /* Set fully written pages uptodate. */
                if (pos == page_offset(page) &&
                    (len == PAGE_SIZE || pos + len == inode->i_size)) {
                        zero_user_segment(page, from + copied, PAGE_SIZE);
                        SetPageUptodate(page);
                }
        }

        set_page_dirty(page);
        unlock_page(page);
        put_page(page);

        mark_inode_dirty_sync(file_inode(file));
        return copied;
}

static void orangefs_invalidatepage(struct page *page,
                                 unsigned int offset,
                                 unsigned int length)
{
        struct orangefs_write_range *wr;
        wr = (struct orangefs_write_range *)page_private(page);

        if (offset == 0 && length == PAGE_SIZE) {
                kfree(detach_page_private(page));
                return;
        /* write range entirely within invalidate range (or equal) */
        } else if (page_offset(page) + offset <= wr->pos &&
            wr->pos + wr->len <= page_offset(page) + offset + length) {
                kfree(detach_page_private(page));
                /* XXX is this right? only caller in fs */
                cancel_dirty_page(page);
                return;
        /* invalidate range chops off end of write range */
        } else if (wr->pos < page_offset(page) + offset &&
            wr->pos + wr->len <= page_offset(page) + offset + length &&
             page_offset(page) + offset < wr->pos + wr->len) {
                size_t x;
                x = wr->pos + wr->len - (page_offset(page) + offset);
                WARN_ON(x > wr->len);
                wr->len -= x;
                wr->uid = current_fsuid();
                wr->gid = current_fsgid();
        /* invalidate range chops off beginning of write range */
        } else if (page_offset(page) + offset <= wr->pos &&
            page_offset(page) + offset + length < wr->pos + wr->len &&
            wr->pos < page_offset(page) + offset + length) {
                size_t x;
                x = page_offset(page) + offset + length - wr->pos;
                WARN_ON(x > wr->len);
                wr->pos += x;
                wr->len -= x;
                wr->uid = current_fsuid();
                wr->gid = current_fsgid();
        /* invalidate range entirely within write range (punch hole) */
        } else if (wr->pos < page_offset(page) + offset &&
            page_offset(page) + offset + length < wr->pos + wr->len) {
                /* XXX what do we do here... should not WARN_ON */
                WARN_ON(1);
                /* punch hole */
                /*
                 * should we just ignore this and write it out anyway?
                 * it hardly makes sense
                 */
                return;
        /* non-overlapping ranges */
        } else {
                /* WARN if they do overlap */
                if (!((page_offset(page) + offset + length <= wr->pos) ^
                    (wr->pos + wr->len <= page_offset(page) + offset))) {
                        WARN_ON(1);
                        printk("invalidate range offset %llu length %u\n",
                            page_offset(page) + offset, length);
                        printk("write range offset %llu length %zu\n",
                            wr->pos, wr->len);
                }
                return;
        }

        /*
         * Above there are returns where wr is freed or where we WARN.
         * Thus the following runs if wr was modified above.
         */

        orangefs_launder_page(page);
}

static int orangefs_releasepage(struct page *page, gfp_t foo)
{
        return !PagePrivate(page);
}

static void orangefs_freepage(struct page *page)
{
        kfree(detach_page_private(page));
}

static int orangefs_launder_page(struct page *page)
{
        int r = 0;
        struct writeback_control wbc = {
                .sync_mode = WB_SYNC_ALL,
                .nr_to_write = 0,
        };
        wait_on_page_writeback(page);
        if (clear_page_dirty_for_io(page)) {
                r = orangefs_writepage_locked(page, &wbc);
                end_page_writeback(page);
        }
        return r;
}

static ssize_t orangefs_direct_IO(struct kiocb *iocb,
                                  struct iov_iter *iter)
{
        /*
         * Comment from original do_readv_writev:
         * Common entry point for read/write/readv/writev
         * This function will dispatch it to either the direct I/O
         * or buffered I/O path depending on the mount options and/or
         * augmented/extended metadata attached to the file.
         * Note: File extended attributes override any mount options.
         */
        struct file *file = iocb->ki_filp;
        loff_t pos = iocb->ki_pos;
        enum ORANGEFS_io_type type = iov_iter_rw(iter) == WRITE ?
            ORANGEFS_IO_WRITE : ORANGEFS_IO_READ;
        loff_t *offset = &pos;
        struct inode *inode = file->f_mapping->host;
        struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
        struct orangefs_khandle *handle = &orangefs_inode->refn.khandle;
        size_t count = iov_iter_count(iter);
        ssize_t total_count = 0;
        ssize_t ret = -EINVAL;
        int i = 0;

        gossip_debug(GOSSIP_FILE_DEBUG,
                "%s-BEGIN(%pU): count(%d) after estimate_max_iovecs.\n",
                __func__,
                handle,
                (int)count);

        if (type == ORANGEFS_IO_WRITE) {
                gossip_debug(GOSSIP_FILE_DEBUG,
                             "%s(%pU): proceeding with offset : %llu, "
                             "size %d\n",
                             __func__,
                             handle,
                             llu(*offset),
                             (int)count);
        }

        if (count == 0) {
                ret = 0;
                goto out;
        }

        while (iov_iter_count(iter)) {
                size_t each_count = iov_iter_count(iter);
                size_t amt_complete;
                i++;

                /* how much to transfer in this loop iteration */
                if (each_count > orangefs_bufmap_size_query())
                        each_count = orangefs_bufmap_size_query();

                gossip_debug(GOSSIP_FILE_DEBUG,
                             "%s(%pU): size of each_count(%d)\n",
                             __func__,
                             handle,
                             (int)each_count);
                gossip_debug(GOSSIP_FILE_DEBUG,
                             "%s(%pU): BEFORE wait_for_io: offset is %d\n",
                             __func__,
                             handle,
                             (int)*offset);

                ret = wait_for_direct_io(type, inode, offset, iter,
                                each_count, 0, NULL, NULL, file);
                gossip_debug(GOSSIP_FILE_DEBUG,
                             "%s(%pU): return from wait_for_io:%d\n",
                             __func__,
                             handle,
                             (int)ret);

                if (ret < 0)
                        goto out;

                *offset += ret;
                total_count += ret;
                amt_complete = ret;

                gossip_debug(GOSSIP_FILE_DEBUG,
                             "%s(%pU): AFTER wait_for_io: offset is %d\n",
                             __func__,
                             handle,
                             (int)*offset);

                /*
                 * if we got a short I/O operations,
                 * fall out and return what we got so far
                 */
                if (amt_complete < each_count)
                        break;
        } /*end while */

out:
        if (total_count > 0)
                ret = total_count;
        if (ret > 0) {
                if (type == ORANGEFS_IO_READ) {
                        file_accessed(file);
                } else {
                        file_update_time(file);
                        if (*offset > i_size_read(inode))
                                i_size_write(inode, *offset);
                }
        }

        gossip_debug(GOSSIP_FILE_DEBUG,
                     "%s(%pU): Value(%d) returned.\n",
                     __func__,
                     handle,
                     (int)ret);

        return ret;
}

/** ORANGEFS2 implementation of address space operations */
static const struct address_space_operations orangefs_address_operations = {
        .writepage = orangefs_writepage,
        .readpage = orangefs_readpage,
        .writepages = orangefs_writepages,
        .set_page_dirty = __set_page_dirty_nobuffers,
        .write_begin = orangefs_write_begin,
        .write_end = orangefs_write_end,
        .invalidatepage = orangefs_invalidatepage,
        .releasepage = orangefs_releasepage,
        .freepage = orangefs_freepage,
        .launder_page = orangefs_launder_page,
        .direct_IO = orangefs_direct_IO,
};

vm_fault_t orangefs_page_mkwrite(struct vm_fault *vmf)
{
        struct page *page = vmf->page;
        struct inode *inode = file_inode(vmf->vma->vm_file);
        struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
        unsigned long *bitlock = &orangefs_inode->bitlock;
        vm_fault_t ret;
        struct orangefs_write_range *wr;

        sb_start_pagefault(inode->i_sb);

        if (wait_on_bit(bitlock, 1, TASK_KILLABLE)) {
                ret = VM_FAULT_RETRY;
                goto out;
        }

        lock_page(page);
        if (PageDirty(page) && !PagePrivate(page)) {
                /*
                 * Should be impossible.  If it happens, launder the page
                 * since we don't know what's dirty.  This will WARN in
                 * orangefs_writepage_locked.
                 */
                if (orangefs_launder_page(page)) {
                        ret = VM_FAULT_LOCKED|VM_FAULT_RETRY;
                        goto out;
                }
        }
        if (PagePrivate(page)) {
                wr = (struct orangefs_write_range *)page_private(page);
                if (uid_eq(wr->uid, current_fsuid()) &&
                    gid_eq(wr->gid, current_fsgid())) {
                        wr->pos = page_offset(page);
                        wr->len = PAGE_SIZE;
                        goto okay;
                } else {
                        if (orangefs_launder_page(page)) {
                                ret = VM_FAULT_LOCKED|VM_FAULT_RETRY;
                                goto out;
                        }
                }
        }
        wr = kmalloc(sizeof *wr, GFP_KERNEL);
        if (!wr) {
                ret = VM_FAULT_LOCKED|VM_FAULT_RETRY;
                goto out;
        }
        wr->pos = page_offset(page);
        wr->len = PAGE_SIZE;
        wr->uid = current_fsuid();
        wr->gid = current_fsgid();
        attach_page_private(page, wr);
okay:

        file_update_time(vmf->vma->vm_file);
        if (page->mapping != inode->i_mapping) {
                unlock_page(page);
                ret = VM_FAULT_LOCKED|VM_FAULT_NOPAGE;
                goto out;
        }

        /*
         * We mark the page dirty already here so that when freeze is in
         * progress, we are guaranteed that writeback during freezing will
         * see the dirty page and writeprotect it again.
         */
        set_page_dirty(page);
        wait_for_stable_page(page);
        ret = VM_FAULT_LOCKED;
out:
        sb_end_pagefault(inode->i_sb);
        return ret;
}

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, ORANGEFS_GETATTR_SIZE);
        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);

        /* This is truncate_setsize in a different order. */
        truncate_pagecache(inode, iattr->ia_size);
        i_size_write(inode, iattr->ia_size);
        if (iattr->ia_size > orig_size)
                pagecache_isize_extended(inode, orig_size, 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, "%s: ret:%d:\n", __func__, 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;
}

int __orangefs_setattr(struct inode *inode, struct iattr *iattr)
{
        int ret;

        if (iattr->ia_valid & ATTR_MODE) {
                if (iattr->ia_mode & (S_ISVTX)) {
                        if (is_root_handle(inode)) {
                                /*
                                 * allow sticky bit to be set on root (since
                                 * it shows up that way by default anyhow),
                                 * but don't show it to the server
                                 */
                                iattr->ia_mode -= S_ISVTX;
                        } else {
                                gossip_debug(GOSSIP_UTILS_DEBUG,
                                             "User attempted to set sticky bit on non-root directory; returning EINVAL.\n");
                                ret = -EINVAL;
                                goto out;
                        }
                }
                if (iattr->ia_mode & (S_ISUID)) {
                        gossip_debug(GOSSIP_UTILS_DEBUG,
                                     "Attempting to set setuid bit (not supported); returning EINVAL.\n");
                        ret = -EINVAL;
                        goto out;
                }
        }

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

again:
        spin_lock(&inode->i_lock);
        if (ORANGEFS_I(inode)->attr_valid) {
                if (uid_eq(ORANGEFS_I(inode)->attr_uid, current_fsuid()) &&
                    gid_eq(ORANGEFS_I(inode)->attr_gid, current_fsgid())) {
                        ORANGEFS_I(inode)->attr_valid = iattr->ia_valid;
                } else {
                        spin_unlock(&inode->i_lock);
                        write_inode_now(inode, 1);
                        goto again;
                }
        } else {
                ORANGEFS_I(inode)->attr_valid = iattr->ia_valid;
                ORANGEFS_I(inode)->attr_uid = current_fsuid();
                ORANGEFS_I(inode)->attr_gid = current_fsgid();
        }
        setattr_copy(inode, iattr);
        spin_unlock(&inode->i_lock);
        mark_inode_dirty(inode);

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

        ret = 0;
out:
        return ret;
}

/*
 * Change attributes of an object referenced by dentry.
 */
int orangefs_setattr(struct dentry *dentry, struct iattr *iattr)
{
        int ret;
        gossip_debug(GOSSIP_INODE_DEBUG, "__orangefs_setattr: called on %pd\n",
            dentry);
        ret = setattr_prepare(dentry, iattr);
        if (ret)
                goto out;
        ret = __orangefs_setattr(d_inode(dentry), iattr);
        sync_inode_metadata(d_inode(dentry), 1);
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(const struct path *path, struct kstat *stat,
                     u32 request_mask, unsigned int flags)
{
        int ret;
        struct inode *inode = path->dentry->d_inode;

        gossip_debug(GOSSIP_INODE_DEBUG,
                     "orangefs_getattr: called on %pd mask %u\n",
                     path->dentry, request_mask);

        ret = orangefs_inode_getattr(inode,
            request_mask & STATX_SIZE ? ORANGEFS_GETATTR_SIZE : 0);
        if (ret == 0) {
                generic_fillattr(inode, stat);

                /* override block size reported to stat */
                if (!(request_mask & STATX_SIZE))
                        stat->result_mask &= ~STATX_SIZE;

                stat->attributes_mask = STATX_ATTR_IMMUTABLE |
                    STATX_ATTR_APPEND;
                if (inode->i_flags & S_IMMUTABLE)
                        stat->attributes |= STATX_ATTR_IMMUTABLE;
                if (inode->i_flags & S_APPEND)
                        stat->attributes |= STATX_ATTR_APPEND;
        }
        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);
        if (ret < 0)
                return ret;

        return generic_permission(inode, mask);
}

int orangefs_update_time(struct inode *inode, struct timespec64 *time, int flags)
{
        struct iattr iattr;
        gossip_debug(GOSSIP_INODE_DEBUG, "orangefs_update_time: %pU\n",
            get_khandle_from_ino(inode));
        generic_update_time(inode, time, flags);
        memset(&iattr, 0, sizeof iattr);
        if (flags & S_ATIME)
                iattr.ia_valid |= ATTR_ATIME;
        if (flags & S_CTIME)
                iattr.ia_valid |= ATTR_CTIME;
        if (flags & S_MTIME)
                iattr.ia_valid |= ATTR_MTIME;
        return __orangefs_setattr(inode, &iattr);
}

/* ORANGEFS2 implementation of VFS inode operations for files */
static const struct inode_operations orangefs_file_inode_operations = {
        .get_acl = orangefs_get_acl,
        .set_acl = orangefs_set_acl,
        .setattr = orangefs_setattr,
        .getattr = orangefs_getattr,
        .listxattr = orangefs_listxattr,
        .permission = orangefs_permission,
        .update_time = orangefs_update_time,
};

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;
                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 an 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;
        ORANGEFS_I(inode)->attr_valid = 0;
        hash_init(ORANGEFS_I(inode)->xattr_cache);
        ORANGEFS_I(inode)->mapping_time = jiffies - 1;
        ORANGEFS_I(inode)->bitlock = 0;
        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);
        /* test handles and fs_ids... */
        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.
 */
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)
                return ERR_PTR(-ENOMEM);

        if (!(inode->i_state & I_NEW))
                return inode;

        error = orangefs_inode_getattr(inode, ORANGEFS_GETATTR_NEW);
        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 ERR_PTR(-ENOMEM);

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

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

        orangefs_init_iops(inode);
        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);
}