105 строки
2.3 KiB
C
105 строки
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2017 Red Hat, Inc.
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* Copyright (c) 2018-2021 Christoph Hellwig.
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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/pagemap.h>
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#include <linux/pagevec.h>
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static loff_t iomap_seek_hole_iter(const struct iomap_iter *iter,
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loff_t *hole_pos)
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{
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loff_t length = iomap_length(iter);
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switch (iter->iomap.type) {
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case IOMAP_UNWRITTEN:
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*hole_pos = mapping_seek_hole_data(iter->inode->i_mapping,
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iter->pos, iter->pos + length, SEEK_HOLE);
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if (*hole_pos == iter->pos + length)
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return length;
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return 0;
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case IOMAP_HOLE:
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*hole_pos = iter->pos;
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return 0;
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default:
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return length;
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}
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}
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loff_t
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iomap_seek_hole(struct inode *inode, loff_t pos, const struct iomap_ops *ops)
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{
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loff_t size = i_size_read(inode);
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struct iomap_iter iter = {
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.inode = inode,
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.pos = pos,
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.flags = IOMAP_REPORT,
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};
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int ret;
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/* Nothing to be found before or beyond the end of the file. */
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if (pos < 0 || pos >= size)
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return -ENXIO;
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iter.len = size - pos;
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while ((ret = iomap_iter(&iter, ops)) > 0)
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iter.processed = iomap_seek_hole_iter(&iter, &pos);
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if (ret < 0)
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return ret;
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if (iter.len) /* found hole before EOF */
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return pos;
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return size;
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}
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EXPORT_SYMBOL_GPL(iomap_seek_hole);
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static loff_t iomap_seek_data_iter(const struct iomap_iter *iter,
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loff_t *hole_pos)
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{
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loff_t length = iomap_length(iter);
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switch (iter->iomap.type) {
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case IOMAP_HOLE:
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return length;
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case IOMAP_UNWRITTEN:
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*hole_pos = mapping_seek_hole_data(iter->inode->i_mapping,
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iter->pos, iter->pos + length, SEEK_DATA);
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if (*hole_pos < 0)
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return length;
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return 0;
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default:
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*hole_pos = iter->pos;
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return 0;
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}
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}
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loff_t
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iomap_seek_data(struct inode *inode, loff_t pos, const struct iomap_ops *ops)
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{
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loff_t size = i_size_read(inode);
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struct iomap_iter iter = {
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.inode = inode,
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.pos = pos,
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.flags = IOMAP_REPORT,
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};
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int ret;
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/* Nothing to be found before or beyond the end of the file. */
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if (pos < 0 || pos >= size)
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return -ENXIO;
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iter.len = size - pos;
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while ((ret = iomap_iter(&iter, ops)) > 0)
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iter.processed = iomap_seek_data_iter(&iter, &pos);
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if (ret < 0)
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return ret;
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if (iter.len) /* found data before EOF */
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return pos;
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/* We've reached the end of the file without finding data */
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return -ENXIO;
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}
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EXPORT_SYMBOL_GPL(iomap_seek_data);
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