linux-stable/fs/iomap/seek.c
Matthew Wilcox (Oracle) 54fa39ac2e iomap: use mapping_seek_hole_data
Enhance mapping_seek_hole_data() to handle partially uptodate pages and
convert the iomap seek code to call it.

Link: https://lkml.kernel.org/r/20201112212641.27837-9-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-26 09:40:59 -08:00

109 lines
2.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2017 Red Hat, Inc.
* Copyright (c) 2018 Christoph Hellwig.
*/
#include <linux/module.h>
#include <linux/compiler.h>
#include <linux/fs.h>
#include <linux/iomap.h>
#include <linux/pagemap.h>
#include <linux/pagevec.h>
static loff_t
iomap_seek_hole_actor(struct inode *inode, loff_t start, loff_t length,
void *data, struct iomap *iomap, struct iomap *srcmap)
{
loff_t offset = start;
switch (iomap->type) {
case IOMAP_UNWRITTEN:
offset = mapping_seek_hole_data(inode->i_mapping, start,
start + length, SEEK_HOLE);
if (offset == start + length)
return length;
fallthrough;
case IOMAP_HOLE:
*(loff_t *)data = offset;
return 0;
default:
return length;
}
}
loff_t
iomap_seek_hole(struct inode *inode, loff_t offset, const struct iomap_ops *ops)
{
loff_t size = i_size_read(inode);
loff_t length = size - offset;
loff_t ret;
/* Nothing to be found before or beyond the end of the file. */
if (offset < 0 || offset >= size)
return -ENXIO;
while (length > 0) {
ret = iomap_apply(inode, offset, length, IOMAP_REPORT, ops,
&offset, iomap_seek_hole_actor);
if (ret < 0)
return ret;
if (ret == 0)
break;
offset += ret;
length -= ret;
}
return offset;
}
EXPORT_SYMBOL_GPL(iomap_seek_hole);
static loff_t
iomap_seek_data_actor(struct inode *inode, loff_t start, loff_t length,
void *data, struct iomap *iomap, struct iomap *srcmap)
{
loff_t offset = start;
switch (iomap->type) {
case IOMAP_HOLE:
return length;
case IOMAP_UNWRITTEN:
offset = mapping_seek_hole_data(inode->i_mapping, start,
start + length, SEEK_DATA);
if (offset < 0)
return length;
fallthrough;
default:
*(loff_t *)data = offset;
return 0;
}
}
loff_t
iomap_seek_data(struct inode *inode, loff_t offset, const struct iomap_ops *ops)
{
loff_t size = i_size_read(inode);
loff_t length = size - offset;
loff_t ret;
/* Nothing to be found before or beyond the end of the file. */
if (offset < 0 || offset >= size)
return -ENXIO;
while (length > 0) {
ret = iomap_apply(inode, offset, length, IOMAP_REPORT, ops,
&offset, iomap_seek_data_actor);
if (ret < 0)
return ret;
if (ret == 0)
break;
offset += ret;
length -= ret;
}
if (length <= 0)
return -ENXIO;
return offset;
}
EXPORT_SYMBOL_GPL(iomap_seek_data);