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![Christoph Hellwig](/assets/img/avatar_default.png)
This adds a full fledget direct I/O implementation using the iomap interface. Full fledged in this case means all features are supported: AIO, vectored I/O, any iov_iter type including kernel pointers, bvecs and pipes, support for hole filling and async apending writes. It does not mean supporting all the warts of the old generic code. We expect i_rwsem to be held over the duration of the call, and we expect to maintain i_dio_count ourselves, and we pass on any kinds of mapping to the file system for now. The algorithm used is very simple: We use iomap_apply to iterate over the range of the I/O, and then we use the new bio_iov_iter_get_pages helper to lock down the user range for the size of the extent. bio_iov_iter_get_pages can currently lock down twice as many pages as the old direct I/O code did, which means that we will have a better batch factor for everything but overwrites of badly fragmented files. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com> Tested-by: Jens Axboe <axboe@fb.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
959 lines
23 KiB
C
959 lines
23 KiB
C
/*
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* Copyright (C) 2010 Red Hat, Inc.
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* Copyright (c) 2016 Christoph Hellwig.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*/
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#include <linux/module.h>
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#include <linux/compiler.h>
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#include <linux/fs.h>
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#include <linux/iomap.h>
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#include <linux/uaccess.h>
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#include <linux/gfp.h>
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#include <linux/mm.h>
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#include <linux/swap.h>
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#include <linux/pagemap.h>
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#include <linux/file.h>
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#include <linux/uio.h>
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#include <linux/backing-dev.h>
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#include <linux/buffer_head.h>
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#include <linux/task_io_accounting_ops.h>
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#include <linux/dax.h>
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#include "internal.h"
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/*
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* Execute a iomap write on a segment of the mapping that spans a
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* contiguous range of pages that have identical block mapping state.
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*
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* This avoids the need to map pages individually, do individual allocations
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* for each page and most importantly avoid the need for filesystem specific
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* locking per page. Instead, all the operations are amortised over the entire
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* range of pages. It is assumed that the filesystems will lock whatever
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* resources they require in the iomap_begin call, and release them in the
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* iomap_end call.
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*/
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loff_t
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iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
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struct iomap_ops *ops, void *data, iomap_actor_t actor)
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{
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struct iomap iomap = { 0 };
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loff_t written = 0, ret;
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/*
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* Need to map a range from start position for length bytes. This can
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* span multiple pages - it is only guaranteed to return a range of a
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* single type of pages (e.g. all into a hole, all mapped or all
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* unwritten). Failure at this point has nothing to undo.
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*
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* If allocation is required for this range, reserve the space now so
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* that the allocation is guaranteed to succeed later on. Once we copy
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* the data into the page cache pages, then we cannot fail otherwise we
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* expose transient stale data. If the reserve fails, we can safely
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* back out at this point as there is nothing to undo.
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*/
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ret = ops->iomap_begin(inode, pos, length, flags, &iomap);
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if (ret)
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return ret;
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if (WARN_ON(iomap.offset > pos))
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return -EIO;
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/*
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* Cut down the length to the one actually provided by the filesystem,
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* as it might not be able to give us the whole size that we requested.
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*/
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if (iomap.offset + iomap.length < pos + length)
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length = iomap.offset + iomap.length - pos;
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/*
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* Now that we have guaranteed that the space allocation will succeed.
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* we can do the copy-in page by page without having to worry about
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* failures exposing transient data.
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*/
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written = actor(inode, pos, length, data, &iomap);
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/*
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* Now the data has been copied, commit the range we've copied. This
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* should not fail unless the filesystem has had a fatal error.
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*/
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if (ops->iomap_end) {
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ret = ops->iomap_end(inode, pos, length,
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written > 0 ? written : 0,
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flags, &iomap);
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}
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return written ? written : ret;
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}
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static void
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iomap_write_failed(struct inode *inode, loff_t pos, unsigned len)
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{
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loff_t i_size = i_size_read(inode);
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/*
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* Only truncate newly allocated pages beyoned EOF, even if the
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* write started inside the existing inode size.
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*/
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if (pos + len > i_size)
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truncate_pagecache_range(inode, max(pos, i_size), pos + len);
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}
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static int
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iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
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struct page **pagep, struct iomap *iomap)
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{
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pgoff_t index = pos >> PAGE_SHIFT;
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struct page *page;
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int status = 0;
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BUG_ON(pos + len > iomap->offset + iomap->length);
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page = grab_cache_page_write_begin(inode->i_mapping, index, flags);
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if (!page)
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return -ENOMEM;
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status = __block_write_begin_int(page, pos, len, NULL, iomap);
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if (unlikely(status)) {
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unlock_page(page);
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put_page(page);
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page = NULL;
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iomap_write_failed(inode, pos, len);
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}
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*pagep = page;
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return status;
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}
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static int
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iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
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unsigned copied, struct page *page)
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{
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int ret;
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ret = generic_write_end(NULL, inode->i_mapping, pos, len,
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copied, page, NULL);
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if (ret < len)
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iomap_write_failed(inode, pos, len);
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return ret;
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}
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static loff_t
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iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
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struct iomap *iomap)
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{
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struct iov_iter *i = data;
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long status = 0;
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ssize_t written = 0;
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unsigned int flags = AOP_FLAG_NOFS;
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/*
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* Copies from kernel address space cannot fail (NFSD is a big user).
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*/
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if (!iter_is_iovec(i))
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flags |= AOP_FLAG_UNINTERRUPTIBLE;
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do {
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struct page *page;
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unsigned long offset; /* Offset into pagecache page */
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unsigned long bytes; /* Bytes to write to page */
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size_t copied; /* Bytes copied from user */
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offset = (pos & (PAGE_SIZE - 1));
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bytes = min_t(unsigned long, PAGE_SIZE - offset,
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iov_iter_count(i));
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again:
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if (bytes > length)
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bytes = length;
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/*
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* Bring in the user page that we will copy from _first_.
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* Otherwise there's a nasty deadlock on copying from the
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* same page as we're writing to, without it being marked
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* up-to-date.
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*
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* Not only is this an optimisation, but it is also required
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* to check that the address is actually valid, when atomic
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* usercopies are used, below.
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*/
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if (unlikely(iov_iter_fault_in_readable(i, bytes))) {
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status = -EFAULT;
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break;
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}
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status = iomap_write_begin(inode, pos, bytes, flags, &page,
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iomap);
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if (unlikely(status))
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break;
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if (mapping_writably_mapped(inode->i_mapping))
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flush_dcache_page(page);
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copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes);
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flush_dcache_page(page);
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status = iomap_write_end(inode, pos, bytes, copied, page);
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if (unlikely(status < 0))
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break;
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copied = status;
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cond_resched();
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iov_iter_advance(i, copied);
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if (unlikely(copied == 0)) {
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/*
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* If we were unable to copy any data at all, we must
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* fall back to a single segment length write.
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*
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* If we didn't fallback here, we could livelock
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* because not all segments in the iov can be copied at
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* once without a pagefault.
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*/
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bytes = min_t(unsigned long, PAGE_SIZE - offset,
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iov_iter_single_seg_count(i));
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goto again;
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}
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pos += copied;
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written += copied;
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length -= copied;
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balance_dirty_pages_ratelimited(inode->i_mapping);
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} while (iov_iter_count(i) && length);
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return written ? written : status;
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}
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ssize_t
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iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *iter,
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struct iomap_ops *ops)
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{
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struct inode *inode = iocb->ki_filp->f_mapping->host;
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loff_t pos = iocb->ki_pos, ret = 0, written = 0;
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while (iov_iter_count(iter)) {
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ret = iomap_apply(inode, pos, iov_iter_count(iter),
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IOMAP_WRITE, ops, iter, iomap_write_actor);
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if (ret <= 0)
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break;
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pos += ret;
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written += ret;
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}
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return written ? written : ret;
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}
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EXPORT_SYMBOL_GPL(iomap_file_buffered_write);
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static struct page *
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__iomap_read_page(struct inode *inode, loff_t offset)
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{
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struct address_space *mapping = inode->i_mapping;
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struct page *page;
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page = read_mapping_page(mapping, offset >> PAGE_SHIFT, NULL);
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if (IS_ERR(page))
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return page;
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if (!PageUptodate(page)) {
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put_page(page);
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return ERR_PTR(-EIO);
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}
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return page;
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}
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static loff_t
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iomap_dirty_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
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struct iomap *iomap)
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{
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long status = 0;
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ssize_t written = 0;
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do {
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struct page *page, *rpage;
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unsigned long offset; /* Offset into pagecache page */
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unsigned long bytes; /* Bytes to write to page */
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offset = (pos & (PAGE_SIZE - 1));
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bytes = min_t(unsigned long, PAGE_SIZE - offset, length);
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rpage = __iomap_read_page(inode, pos);
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if (IS_ERR(rpage))
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return PTR_ERR(rpage);
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status = iomap_write_begin(inode, pos, bytes,
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AOP_FLAG_NOFS | AOP_FLAG_UNINTERRUPTIBLE,
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&page, iomap);
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put_page(rpage);
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if (unlikely(status))
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return status;
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WARN_ON_ONCE(!PageUptodate(page));
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status = iomap_write_end(inode, pos, bytes, bytes, page);
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if (unlikely(status <= 0)) {
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if (WARN_ON_ONCE(status == 0))
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return -EIO;
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return status;
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}
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cond_resched();
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pos += status;
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written += status;
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length -= status;
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balance_dirty_pages_ratelimited(inode->i_mapping);
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} while (length);
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return written;
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}
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int
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iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,
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struct iomap_ops *ops)
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{
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loff_t ret;
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while (len) {
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ret = iomap_apply(inode, pos, len, IOMAP_WRITE, ops, NULL,
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iomap_dirty_actor);
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if (ret <= 0)
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return ret;
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pos += ret;
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len -= ret;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(iomap_file_dirty);
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static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset,
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unsigned bytes, struct iomap *iomap)
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{
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struct page *page;
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int status;
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status = iomap_write_begin(inode, pos, bytes,
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AOP_FLAG_UNINTERRUPTIBLE | AOP_FLAG_NOFS, &page, iomap);
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if (status)
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return status;
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zero_user(page, offset, bytes);
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mark_page_accessed(page);
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return iomap_write_end(inode, pos, bytes, bytes, page);
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}
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static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes,
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struct iomap *iomap)
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{
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sector_t sector = iomap->blkno +
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(((pos & ~(PAGE_SIZE - 1)) - iomap->offset) >> 9);
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return __dax_zero_page_range(iomap->bdev, sector, offset, bytes);
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}
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static loff_t
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iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count,
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void *data, struct iomap *iomap)
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{
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bool *did_zero = data;
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loff_t written = 0;
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int status;
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/* already zeroed? we're done. */
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if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN)
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return count;
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do {
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unsigned offset, bytes;
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offset = pos & (PAGE_SIZE - 1); /* Within page */
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bytes = min_t(unsigned, PAGE_SIZE - offset, count);
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if (IS_DAX(inode))
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status = iomap_dax_zero(pos, offset, bytes, iomap);
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else
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status = iomap_zero(inode, pos, offset, bytes, iomap);
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if (status < 0)
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return status;
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pos += bytes;
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count -= bytes;
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written += bytes;
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if (did_zero)
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*did_zero = true;
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} while (count > 0);
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return written;
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}
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int
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iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
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struct iomap_ops *ops)
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{
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loff_t ret;
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while (len > 0) {
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ret = iomap_apply(inode, pos, len, IOMAP_ZERO,
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ops, did_zero, iomap_zero_range_actor);
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if (ret <= 0)
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return ret;
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pos += ret;
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len -= ret;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(iomap_zero_range);
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int
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iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
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struct iomap_ops *ops)
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{
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unsigned blocksize = (1 << inode->i_blkbits);
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unsigned off = pos & (blocksize - 1);
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/* Block boundary? Nothing to do */
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if (!off)
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return 0;
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return iomap_zero_range(inode, pos, blocksize - off, did_zero, ops);
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}
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EXPORT_SYMBOL_GPL(iomap_truncate_page);
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static loff_t
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iomap_page_mkwrite_actor(struct inode *inode, loff_t pos, loff_t length,
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void *data, struct iomap *iomap)
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{
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struct page *page = data;
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int ret;
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ret = __block_write_begin_int(page, pos, length, NULL, iomap);
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if (ret)
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return ret;
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block_commit_write(page, 0, length);
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return length;
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}
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int iomap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
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struct iomap_ops *ops)
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{
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struct page *page = vmf->page;
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struct inode *inode = file_inode(vma->vm_file);
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unsigned long length;
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loff_t offset, size;
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ssize_t ret;
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lock_page(page);
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size = i_size_read(inode);
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if ((page->mapping != inode->i_mapping) ||
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(page_offset(page) > size)) {
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/* We overload EFAULT to mean page got truncated */
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ret = -EFAULT;
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goto out_unlock;
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}
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/* page is wholly or partially inside EOF */
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if (((page->index + 1) << PAGE_SHIFT) > size)
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length = size & ~PAGE_MASK;
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else
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length = PAGE_SIZE;
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offset = page_offset(page);
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while (length > 0) {
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ret = iomap_apply(inode, offset, length,
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IOMAP_WRITE | IOMAP_FAULT, ops, page,
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iomap_page_mkwrite_actor);
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if (unlikely(ret <= 0))
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goto out_unlock;
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offset += ret;
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length -= ret;
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}
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set_page_dirty(page);
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wait_for_stable_page(page);
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return 0;
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out_unlock:
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unlock_page(page);
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return ret;
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}
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EXPORT_SYMBOL_GPL(iomap_page_mkwrite);
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struct fiemap_ctx {
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struct fiemap_extent_info *fi;
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struct iomap prev;
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};
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static int iomap_to_fiemap(struct fiemap_extent_info *fi,
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struct iomap *iomap, u32 flags)
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{
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switch (iomap->type) {
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case IOMAP_HOLE:
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/* skip holes */
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return 0;
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case IOMAP_DELALLOC:
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flags |= FIEMAP_EXTENT_DELALLOC | FIEMAP_EXTENT_UNKNOWN;
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break;
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case IOMAP_UNWRITTEN:
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flags |= FIEMAP_EXTENT_UNWRITTEN;
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break;
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case IOMAP_MAPPED:
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break;
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}
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if (iomap->flags & IOMAP_F_MERGED)
|
|
flags |= FIEMAP_EXTENT_MERGED;
|
|
if (iomap->flags & IOMAP_F_SHARED)
|
|
flags |= FIEMAP_EXTENT_SHARED;
|
|
|
|
return fiemap_fill_next_extent(fi, iomap->offset,
|
|
iomap->blkno != IOMAP_NULL_BLOCK ? iomap->blkno << 9: 0,
|
|
iomap->length, flags);
|
|
|
|
}
|
|
|
|
static loff_t
|
|
iomap_fiemap_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
|
|
struct iomap *iomap)
|
|
{
|
|
struct fiemap_ctx *ctx = data;
|
|
loff_t ret = length;
|
|
|
|
if (iomap->type == IOMAP_HOLE)
|
|
return length;
|
|
|
|
ret = iomap_to_fiemap(ctx->fi, &ctx->prev, 0);
|
|
ctx->prev = *iomap;
|
|
switch (ret) {
|
|
case 0: /* success */
|
|
return length;
|
|
case 1: /* extent array full */
|
|
return 0;
|
|
default:
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fi,
|
|
loff_t start, loff_t len, struct iomap_ops *ops)
|
|
{
|
|
struct fiemap_ctx ctx;
|
|
loff_t ret;
|
|
|
|
memset(&ctx, 0, sizeof(ctx));
|
|
ctx.fi = fi;
|
|
ctx.prev.type = IOMAP_HOLE;
|
|
|
|
ret = fiemap_check_flags(fi, FIEMAP_FLAG_SYNC);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (fi->fi_flags & FIEMAP_FLAG_SYNC) {
|
|
ret = filemap_write_and_wait(inode->i_mapping);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
while (len > 0) {
|
|
ret = iomap_apply(inode, start, len, IOMAP_REPORT, ops, &ctx,
|
|
iomap_fiemap_actor);
|
|
/* inode with no (attribute) mapping will give ENOENT */
|
|
if (ret == -ENOENT)
|
|
break;
|
|
if (ret < 0)
|
|
return ret;
|
|
if (ret == 0)
|
|
break;
|
|
|
|
start += ret;
|
|
len -= ret;
|
|
}
|
|
|
|
if (ctx.prev.type != IOMAP_HOLE) {
|
|
ret = iomap_to_fiemap(fi, &ctx.prev, FIEMAP_EXTENT_LAST);
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(iomap_fiemap);
|
|
|
|
/*
|
|
* Private flags for iomap_dio, must not overlap with the public ones in
|
|
* iomap.h:
|
|
*/
|
|
#define IOMAP_DIO_WRITE (1 << 30)
|
|
#define IOMAP_DIO_DIRTY (1 << 31)
|
|
|
|
struct iomap_dio {
|
|
struct kiocb *iocb;
|
|
iomap_dio_end_io_t *end_io;
|
|
loff_t i_size;
|
|
loff_t size;
|
|
atomic_t ref;
|
|
unsigned flags;
|
|
int error;
|
|
|
|
union {
|
|
/* used during submission and for synchronous completion: */
|
|
struct {
|
|
struct iov_iter *iter;
|
|
struct task_struct *waiter;
|
|
struct request_queue *last_queue;
|
|
blk_qc_t cookie;
|
|
} submit;
|
|
|
|
/* used for aio completion: */
|
|
struct {
|
|
struct work_struct work;
|
|
} aio;
|
|
};
|
|
};
|
|
|
|
static ssize_t iomap_dio_complete(struct iomap_dio *dio)
|
|
{
|
|
struct kiocb *iocb = dio->iocb;
|
|
ssize_t ret;
|
|
|
|
if (dio->end_io) {
|
|
ret = dio->end_io(iocb,
|
|
dio->error ? dio->error : dio->size,
|
|
dio->flags);
|
|
} else {
|
|
ret = dio->error;
|
|
}
|
|
|
|
if (likely(!ret)) {
|
|
ret = dio->size;
|
|
/* check for short read */
|
|
if (iocb->ki_pos + ret > dio->i_size &&
|
|
!(dio->flags & IOMAP_DIO_WRITE))
|
|
ret = dio->i_size - iocb->ki_pos;
|
|
iocb->ki_pos += ret;
|
|
}
|
|
|
|
inode_dio_end(file_inode(iocb->ki_filp));
|
|
kfree(dio);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void iomap_dio_complete_work(struct work_struct *work)
|
|
{
|
|
struct iomap_dio *dio = container_of(work, struct iomap_dio, aio.work);
|
|
struct kiocb *iocb = dio->iocb;
|
|
bool is_write = (dio->flags & IOMAP_DIO_WRITE);
|
|
ssize_t ret;
|
|
|
|
ret = iomap_dio_complete(dio);
|
|
if (is_write && ret > 0)
|
|
ret = generic_write_sync(iocb, ret);
|
|
iocb->ki_complete(iocb, ret, 0);
|
|
}
|
|
|
|
/*
|
|
* Set an error in the dio if none is set yet. We have to use cmpxchg
|
|
* as the submission context and the completion context(s) can race to
|
|
* update the error.
|
|
*/
|
|
static inline void iomap_dio_set_error(struct iomap_dio *dio, int ret)
|
|
{
|
|
cmpxchg(&dio->error, 0, ret);
|
|
}
|
|
|
|
static void iomap_dio_bio_end_io(struct bio *bio)
|
|
{
|
|
struct iomap_dio *dio = bio->bi_private;
|
|
bool should_dirty = (dio->flags & IOMAP_DIO_DIRTY);
|
|
|
|
if (bio->bi_error)
|
|
iomap_dio_set_error(dio, bio->bi_error);
|
|
|
|
if (atomic_dec_and_test(&dio->ref)) {
|
|
if (is_sync_kiocb(dio->iocb)) {
|
|
struct task_struct *waiter = dio->submit.waiter;
|
|
|
|
WRITE_ONCE(dio->submit.waiter, NULL);
|
|
wake_up_process(waiter);
|
|
} else if (dio->flags & IOMAP_DIO_WRITE) {
|
|
struct inode *inode = file_inode(dio->iocb->ki_filp);
|
|
|
|
INIT_WORK(&dio->aio.work, iomap_dio_complete_work);
|
|
queue_work(inode->i_sb->s_dio_done_wq, &dio->aio.work);
|
|
} else {
|
|
iomap_dio_complete_work(&dio->aio.work);
|
|
}
|
|
}
|
|
|
|
if (should_dirty) {
|
|
bio_check_pages_dirty(bio);
|
|
} else {
|
|
struct bio_vec *bvec;
|
|
int i;
|
|
|
|
bio_for_each_segment_all(bvec, bio, i)
|
|
put_page(bvec->bv_page);
|
|
bio_put(bio);
|
|
}
|
|
}
|
|
|
|
static blk_qc_t
|
|
iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos,
|
|
unsigned len)
|
|
{
|
|
struct page *page = ZERO_PAGE(0);
|
|
struct bio *bio;
|
|
|
|
bio = bio_alloc(GFP_KERNEL, 1);
|
|
bio->bi_bdev = iomap->bdev;
|
|
bio->bi_iter.bi_sector =
|
|
iomap->blkno + ((pos - iomap->offset) >> 9);
|
|
bio->bi_private = dio;
|
|
bio->bi_end_io = iomap_dio_bio_end_io;
|
|
|
|
get_page(page);
|
|
if (bio_add_page(bio, page, len, 0) != len)
|
|
BUG();
|
|
bio_set_op_attrs(bio, REQ_OP_WRITE, WRITE_ODIRECT);
|
|
|
|
atomic_inc(&dio->ref);
|
|
return submit_bio(bio);
|
|
}
|
|
|
|
static loff_t
|
|
iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length,
|
|
void *data, struct iomap *iomap)
|
|
{
|
|
struct iomap_dio *dio = data;
|
|
unsigned blkbits = blksize_bits(bdev_logical_block_size(iomap->bdev));
|
|
unsigned fs_block_size = (1 << inode->i_blkbits), pad;
|
|
unsigned align = iov_iter_alignment(dio->submit.iter);
|
|
struct iov_iter iter;
|
|
struct bio *bio;
|
|
bool need_zeroout = false;
|
|
int nr_pages, ret;
|
|
|
|
if ((pos | length | align) & ((1 << blkbits) - 1))
|
|
return -EINVAL;
|
|
|
|
switch (iomap->type) {
|
|
case IOMAP_HOLE:
|
|
if (WARN_ON_ONCE(dio->flags & IOMAP_DIO_WRITE))
|
|
return -EIO;
|
|
/*FALLTHRU*/
|
|
case IOMAP_UNWRITTEN:
|
|
if (!(dio->flags & IOMAP_DIO_WRITE)) {
|
|
iov_iter_zero(length, dio->submit.iter);
|
|
dio->size += length;
|
|
return length;
|
|
}
|
|
dio->flags |= IOMAP_DIO_UNWRITTEN;
|
|
need_zeroout = true;
|
|
break;
|
|
case IOMAP_MAPPED:
|
|
if (iomap->flags & IOMAP_F_SHARED)
|
|
dio->flags |= IOMAP_DIO_COW;
|
|
if (iomap->flags & IOMAP_F_NEW)
|
|
need_zeroout = true;
|
|
break;
|
|
default:
|
|
WARN_ON_ONCE(1);
|
|
return -EIO;
|
|
}
|
|
|
|
/*
|
|
* Operate on a partial iter trimmed to the extent we were called for.
|
|
* We'll update the iter in the dio once we're done with this extent.
|
|
*/
|
|
iter = *dio->submit.iter;
|
|
iov_iter_truncate(&iter, length);
|
|
|
|
nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES);
|
|
if (nr_pages <= 0)
|
|
return nr_pages;
|
|
|
|
if (need_zeroout) {
|
|
/* zero out from the start of the block to the write offset */
|
|
pad = pos & (fs_block_size - 1);
|
|
if (pad)
|
|
iomap_dio_zero(dio, iomap, pos - pad, pad);
|
|
}
|
|
|
|
do {
|
|
if (dio->error)
|
|
return 0;
|
|
|
|
bio = bio_alloc(GFP_KERNEL, nr_pages);
|
|
bio->bi_bdev = iomap->bdev;
|
|
bio->bi_iter.bi_sector =
|
|
iomap->blkno + ((pos - iomap->offset) >> 9);
|
|
bio->bi_private = dio;
|
|
bio->bi_end_io = iomap_dio_bio_end_io;
|
|
|
|
ret = bio_iov_iter_get_pages(bio, &iter);
|
|
if (unlikely(ret)) {
|
|
bio_put(bio);
|
|
return ret;
|
|
}
|
|
|
|
if (dio->flags & IOMAP_DIO_WRITE) {
|
|
bio_set_op_attrs(bio, REQ_OP_WRITE, WRITE_ODIRECT);
|
|
task_io_account_write(bio->bi_iter.bi_size);
|
|
} else {
|
|
bio_set_op_attrs(bio, REQ_OP_READ, 0);
|
|
if (dio->flags & IOMAP_DIO_DIRTY)
|
|
bio_set_pages_dirty(bio);
|
|
}
|
|
|
|
dio->size += bio->bi_iter.bi_size;
|
|
pos += bio->bi_iter.bi_size;
|
|
|
|
nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES);
|
|
|
|
atomic_inc(&dio->ref);
|
|
|
|
dio->submit.last_queue = bdev_get_queue(iomap->bdev);
|
|
dio->submit.cookie = submit_bio(bio);
|
|
} while (nr_pages);
|
|
|
|
if (need_zeroout) {
|
|
/* zero out from the end of the write to the end of the block */
|
|
pad = pos & (fs_block_size - 1);
|
|
if (pad)
|
|
iomap_dio_zero(dio, iomap, pos, fs_block_size - pad);
|
|
}
|
|
|
|
iov_iter_advance(dio->submit.iter, length);
|
|
return length;
|
|
}
|
|
|
|
ssize_t
|
|
iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, struct iomap_ops *ops,
|
|
iomap_dio_end_io_t end_io)
|
|
{
|
|
struct address_space *mapping = iocb->ki_filp->f_mapping;
|
|
struct inode *inode = file_inode(iocb->ki_filp);
|
|
size_t count = iov_iter_count(iter);
|
|
loff_t pos = iocb->ki_pos, end = iocb->ki_pos + count - 1, ret = 0;
|
|
unsigned int flags = IOMAP_DIRECT;
|
|
struct blk_plug plug;
|
|
struct iomap_dio *dio;
|
|
|
|
lockdep_assert_held(&inode->i_rwsem);
|
|
|
|
if (!count)
|
|
return 0;
|
|
|
|
dio = kmalloc(sizeof(*dio), GFP_KERNEL);
|
|
if (!dio)
|
|
return -ENOMEM;
|
|
|
|
dio->iocb = iocb;
|
|
atomic_set(&dio->ref, 1);
|
|
dio->size = 0;
|
|
dio->i_size = i_size_read(inode);
|
|
dio->end_io = end_io;
|
|
dio->error = 0;
|
|
dio->flags = 0;
|
|
|
|
dio->submit.iter = iter;
|
|
if (is_sync_kiocb(iocb)) {
|
|
dio->submit.waiter = current;
|
|
dio->submit.cookie = BLK_QC_T_NONE;
|
|
dio->submit.last_queue = NULL;
|
|
}
|
|
|
|
if (iov_iter_rw(iter) == READ) {
|
|
if (pos >= dio->i_size)
|
|
goto out_free_dio;
|
|
|
|
if (iter->type == ITER_IOVEC)
|
|
dio->flags |= IOMAP_DIO_DIRTY;
|
|
} else {
|
|
dio->flags |= IOMAP_DIO_WRITE;
|
|
flags |= IOMAP_WRITE;
|
|
}
|
|
|
|
if (mapping->nrpages) {
|
|
ret = filemap_write_and_wait_range(mapping, iocb->ki_pos, end);
|
|
if (ret)
|
|
goto out_free_dio;
|
|
|
|
ret = invalidate_inode_pages2_range(mapping,
|
|
iocb->ki_pos >> PAGE_SHIFT, end >> PAGE_SHIFT);
|
|
WARN_ON_ONCE(ret);
|
|
ret = 0;
|
|
}
|
|
|
|
inode_dio_begin(inode);
|
|
|
|
blk_start_plug(&plug);
|
|
do {
|
|
ret = iomap_apply(inode, pos, count, flags, ops, dio,
|
|
iomap_dio_actor);
|
|
if (ret <= 0) {
|
|
/* magic error code to fall back to buffered I/O */
|
|
if (ret == -ENOTBLK)
|
|
ret = 0;
|
|
break;
|
|
}
|
|
pos += ret;
|
|
} while ((count = iov_iter_count(iter)) > 0);
|
|
blk_finish_plug(&plug);
|
|
|
|
if (ret < 0)
|
|
iomap_dio_set_error(dio, ret);
|
|
|
|
if (ret >= 0 && iov_iter_rw(iter) == WRITE && !is_sync_kiocb(iocb) &&
|
|
!inode->i_sb->s_dio_done_wq) {
|
|
ret = sb_init_dio_done_wq(inode->i_sb);
|
|
if (ret < 0)
|
|
iomap_dio_set_error(dio, ret);
|
|
}
|
|
|
|
if (!atomic_dec_and_test(&dio->ref)) {
|
|
if (!is_sync_kiocb(iocb))
|
|
return -EIOCBQUEUED;
|
|
|
|
for (;;) {
|
|
set_current_state(TASK_UNINTERRUPTIBLE);
|
|
if (!READ_ONCE(dio->submit.waiter))
|
|
break;
|
|
|
|
if (!(iocb->ki_flags & IOCB_HIPRI) ||
|
|
!dio->submit.last_queue ||
|
|
!blk_poll(dio->submit.last_queue,
|
|
dio->submit.cookie))
|
|
io_schedule();
|
|
}
|
|
__set_current_state(TASK_RUNNING);
|
|
}
|
|
|
|
/*
|
|
* Try again to invalidate clean pages which might have been cached by
|
|
* non-direct readahead, or faulted in by get_user_pages() if the source
|
|
* of the write was an mmap'ed region of the file we're writing. Either
|
|
* one is a pretty crazy thing to do, so we don't support it 100%. If
|
|
* this invalidation fails, tough, the write still worked...
|
|
*/
|
|
if (iov_iter_rw(iter) == WRITE && mapping->nrpages) {
|
|
ret = invalidate_inode_pages2_range(mapping,
|
|
iocb->ki_pos >> PAGE_SHIFT, end >> PAGE_SHIFT);
|
|
WARN_ON_ONCE(ret);
|
|
}
|
|
|
|
return iomap_dio_complete(dio);
|
|
|
|
out_free_dio:
|
|
kfree(dio);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(iomap_dio_rw);
|