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![Andreas Gruenbacher](/assets/img/avatar_default.png)
Change iomap_read_inline_data to return 0 or an error code; this simplifies the callers. Add a description. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> [djwong: document the return value of iomap_read_inline_data explicitly] Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
1527 lines
41 KiB
C
1527 lines
41 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2010 Red Hat, Inc.
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* Copyright (C) 2016-2019 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/uio.h>
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#include <linux/buffer_head.h>
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#include <linux/dax.h>
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#include <linux/writeback.h>
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#include <linux/list_sort.h>
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#include <linux/swap.h>
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#include <linux/bio.h>
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#include <linux/sched/signal.h>
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#include <linux/migrate.h>
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#include "trace.h"
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#include "../internal.h"
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/*
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* Structure allocated for each page or THP when block size < page size
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* to track sub-page uptodate status and I/O completions.
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*/
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struct iomap_page {
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atomic_t read_bytes_pending;
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atomic_t write_bytes_pending;
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spinlock_t uptodate_lock;
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unsigned long uptodate[];
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};
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static inline struct iomap_page *to_iomap_page(struct page *page)
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{
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/*
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* per-block data is stored in the head page. Callers should
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* not be dealing with tail pages, and if they are, they can
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* call thp_head() first.
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*/
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VM_BUG_ON_PGFLAGS(PageTail(page), page);
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if (page_has_private(page))
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return (struct iomap_page *)page_private(page);
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return NULL;
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}
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static struct bio_set iomap_ioend_bioset;
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static struct iomap_page *
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iomap_page_create(struct inode *inode, struct page *page)
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{
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struct iomap_page *iop = to_iomap_page(page);
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unsigned int nr_blocks = i_blocks_per_page(inode, page);
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if (iop || nr_blocks <= 1)
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return iop;
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iop = kzalloc(struct_size(iop, uptodate, BITS_TO_LONGS(nr_blocks)),
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GFP_NOFS | __GFP_NOFAIL);
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spin_lock_init(&iop->uptodate_lock);
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if (PageUptodate(page))
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bitmap_fill(iop->uptodate, nr_blocks);
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attach_page_private(page, iop);
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return iop;
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}
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static void
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iomap_page_release(struct page *page)
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{
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struct iomap_page *iop = detach_page_private(page);
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unsigned int nr_blocks = i_blocks_per_page(page->mapping->host, page);
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if (!iop)
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return;
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WARN_ON_ONCE(atomic_read(&iop->read_bytes_pending));
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WARN_ON_ONCE(atomic_read(&iop->write_bytes_pending));
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WARN_ON_ONCE(bitmap_full(iop->uptodate, nr_blocks) !=
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PageUptodate(page));
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kfree(iop);
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}
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/*
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* Calculate the range inside the page that we actually need to read.
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*/
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static void
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iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop,
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loff_t *pos, loff_t length, unsigned *offp, unsigned *lenp)
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{
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loff_t orig_pos = *pos;
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loff_t isize = i_size_read(inode);
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unsigned block_bits = inode->i_blkbits;
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unsigned block_size = (1 << block_bits);
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unsigned poff = offset_in_page(*pos);
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unsigned plen = min_t(loff_t, PAGE_SIZE - poff, length);
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unsigned first = poff >> block_bits;
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unsigned last = (poff + plen - 1) >> block_bits;
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/*
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* If the block size is smaller than the page size, we need to check the
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* per-block uptodate status and adjust the offset and length if needed
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* to avoid reading in already uptodate ranges.
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*/
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if (iop) {
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unsigned int i;
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/* move forward for each leading block marked uptodate */
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for (i = first; i <= last; i++) {
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if (!test_bit(i, iop->uptodate))
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break;
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*pos += block_size;
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poff += block_size;
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plen -= block_size;
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first++;
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}
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/* truncate len if we find any trailing uptodate block(s) */
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for ( ; i <= last; i++) {
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if (test_bit(i, iop->uptodate)) {
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plen -= (last - i + 1) * block_size;
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last = i - 1;
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break;
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}
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}
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}
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/*
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* If the extent spans the block that contains the i_size, we need to
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* handle both halves separately so that we properly zero data in the
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* page cache for blocks that are entirely outside of i_size.
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*/
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if (orig_pos <= isize && orig_pos + length > isize) {
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unsigned end = offset_in_page(isize - 1) >> block_bits;
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if (first <= end && last > end)
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plen -= (last - end) * block_size;
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}
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*offp = poff;
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*lenp = plen;
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}
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static void
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iomap_iop_set_range_uptodate(struct page *page, unsigned off, unsigned len)
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{
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struct iomap_page *iop = to_iomap_page(page);
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struct inode *inode = page->mapping->host;
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unsigned first = off >> inode->i_blkbits;
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unsigned last = (off + len - 1) >> inode->i_blkbits;
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unsigned long flags;
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spin_lock_irqsave(&iop->uptodate_lock, flags);
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bitmap_set(iop->uptodate, first, last - first + 1);
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if (bitmap_full(iop->uptodate, i_blocks_per_page(inode, page)))
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SetPageUptodate(page);
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spin_unlock_irqrestore(&iop->uptodate_lock, flags);
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}
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static void
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iomap_set_range_uptodate(struct page *page, unsigned off, unsigned len)
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{
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if (PageError(page))
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return;
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if (page_has_private(page))
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iomap_iop_set_range_uptodate(page, off, len);
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else
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SetPageUptodate(page);
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}
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static void
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iomap_read_page_end_io(struct bio_vec *bvec, int error)
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{
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struct page *page = bvec->bv_page;
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struct iomap_page *iop = to_iomap_page(page);
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if (unlikely(error)) {
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ClearPageUptodate(page);
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SetPageError(page);
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} else {
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iomap_set_range_uptodate(page, bvec->bv_offset, bvec->bv_len);
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}
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if (!iop || atomic_sub_and_test(bvec->bv_len, &iop->read_bytes_pending))
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unlock_page(page);
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}
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static void
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iomap_read_end_io(struct bio *bio)
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{
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int error = blk_status_to_errno(bio->bi_status);
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struct bio_vec *bvec;
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struct bvec_iter_all iter_all;
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bio_for_each_segment_all(bvec, bio, iter_all)
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iomap_read_page_end_io(bvec, error);
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bio_put(bio);
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}
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struct iomap_readpage_ctx {
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struct page *cur_page;
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bool cur_page_in_bio;
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struct bio *bio;
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struct readahead_control *rac;
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};
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/**
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* iomap_read_inline_data - copy inline data into the page cache
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* @iter: iteration structure
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* @page: page to copy to
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*
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* Copy the inline data in @iter into @page and zero out the rest of the page.
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* Only a single IOMAP_INLINE extent is allowed at the end of each file.
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* Returns zero for success to complete the read, or the usual negative errno.
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*/
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static int iomap_read_inline_data(const struct iomap_iter *iter,
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struct page *page)
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{
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const struct iomap *iomap = iomap_iter_srcmap(iter);
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size_t size = i_size_read(iter->inode) - iomap->offset;
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size_t poff = offset_in_page(iomap->offset);
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void *addr;
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if (PageUptodate(page))
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return 0;
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if (WARN_ON_ONCE(size > PAGE_SIZE - poff))
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return -EIO;
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if (WARN_ON_ONCE(size > PAGE_SIZE -
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offset_in_page(iomap->inline_data)))
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return -EIO;
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if (WARN_ON_ONCE(size > iomap->length))
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return -EIO;
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if (poff > 0)
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iomap_page_create(iter->inode, page);
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addr = kmap_local_page(page) + poff;
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memcpy(addr, iomap->inline_data, size);
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memset(addr + size, 0, PAGE_SIZE - poff - size);
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kunmap_local(addr);
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iomap_set_range_uptodate(page, poff, PAGE_SIZE - poff);
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return 0;
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}
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static inline bool iomap_block_needs_zeroing(const struct iomap_iter *iter,
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loff_t pos)
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{
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const struct iomap *srcmap = iomap_iter_srcmap(iter);
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return srcmap->type != IOMAP_MAPPED ||
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(srcmap->flags & IOMAP_F_NEW) ||
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pos >= i_size_read(iter->inode);
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}
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static loff_t iomap_readpage_iter(const struct iomap_iter *iter,
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struct iomap_readpage_ctx *ctx, loff_t offset)
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{
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const struct iomap *iomap = &iter->iomap;
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loff_t pos = iter->pos + offset;
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loff_t length = iomap_length(iter) - offset;
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struct page *page = ctx->cur_page;
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struct iomap_page *iop;
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loff_t orig_pos = pos;
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unsigned poff, plen;
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sector_t sector;
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if (iomap->type == IOMAP_INLINE)
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return iomap_read_inline_data(iter, page);
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/* zero post-eof blocks as the page may be mapped */
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iop = iomap_page_create(iter->inode, page);
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iomap_adjust_read_range(iter->inode, iop, &pos, length, &poff, &plen);
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if (plen == 0)
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goto done;
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if (iomap_block_needs_zeroing(iter, pos)) {
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zero_user(page, poff, plen);
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iomap_set_range_uptodate(page, poff, plen);
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goto done;
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}
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ctx->cur_page_in_bio = true;
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if (iop)
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atomic_add(plen, &iop->read_bytes_pending);
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sector = iomap_sector(iomap, pos);
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if (!ctx->bio ||
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bio_end_sector(ctx->bio) != sector ||
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bio_add_page(ctx->bio, page, plen, poff) != plen) {
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gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL);
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gfp_t orig_gfp = gfp;
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unsigned int nr_vecs = DIV_ROUND_UP(length, PAGE_SIZE);
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if (ctx->bio)
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submit_bio(ctx->bio);
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if (ctx->rac) /* same as readahead_gfp_mask */
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gfp |= __GFP_NORETRY | __GFP_NOWARN;
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ctx->bio = bio_alloc(gfp, bio_max_segs(nr_vecs));
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/*
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* If the bio_alloc fails, try it again for a single page to
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* avoid having to deal with partial page reads. This emulates
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* what do_mpage_readpage does.
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*/
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if (!ctx->bio)
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ctx->bio = bio_alloc(orig_gfp, 1);
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ctx->bio->bi_opf = REQ_OP_READ;
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if (ctx->rac)
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ctx->bio->bi_opf |= REQ_RAHEAD;
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ctx->bio->bi_iter.bi_sector = sector;
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bio_set_dev(ctx->bio, iomap->bdev);
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ctx->bio->bi_end_io = iomap_read_end_io;
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__bio_add_page(ctx->bio, page, plen, poff);
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}
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done:
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/*
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* Move the caller beyond our range so that it keeps making progress.
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* For that, we have to include any leading non-uptodate ranges, but
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* we can skip trailing ones as they will be handled in the next
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* iteration.
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*/
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return pos - orig_pos + plen;
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}
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int
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iomap_readpage(struct page *page, const struct iomap_ops *ops)
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{
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struct iomap_iter iter = {
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.inode = page->mapping->host,
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.pos = page_offset(page),
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.len = PAGE_SIZE,
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};
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struct iomap_readpage_ctx ctx = {
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.cur_page = page,
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};
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int ret;
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trace_iomap_readpage(page->mapping->host, 1);
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while ((ret = iomap_iter(&iter, ops)) > 0)
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iter.processed = iomap_readpage_iter(&iter, &ctx, 0);
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if (ret < 0)
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SetPageError(page);
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if (ctx.bio) {
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submit_bio(ctx.bio);
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WARN_ON_ONCE(!ctx.cur_page_in_bio);
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} else {
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WARN_ON_ONCE(ctx.cur_page_in_bio);
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unlock_page(page);
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}
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/*
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* Just like mpage_readahead and block_read_full_page, we always
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* return 0 and just mark the page as PageError on errors. This
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* should be cleaned up throughout the stack eventually.
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*/
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return 0;
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}
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EXPORT_SYMBOL_GPL(iomap_readpage);
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static loff_t iomap_readahead_iter(const struct iomap_iter *iter,
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struct iomap_readpage_ctx *ctx)
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{
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loff_t length = iomap_length(iter);
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loff_t done, ret;
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for (done = 0; done < length; done += ret) {
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if (ctx->cur_page && offset_in_page(iter->pos + done) == 0) {
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if (!ctx->cur_page_in_bio)
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unlock_page(ctx->cur_page);
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put_page(ctx->cur_page);
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ctx->cur_page = NULL;
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}
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if (!ctx->cur_page) {
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ctx->cur_page = readahead_page(ctx->rac);
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ctx->cur_page_in_bio = false;
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}
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ret = iomap_readpage_iter(iter, ctx, done);
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if (ret <= 0)
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return ret;
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}
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return done;
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}
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/**
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* iomap_readahead - Attempt to read pages from a file.
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* @rac: Describes the pages to be read.
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* @ops: The operations vector for the filesystem.
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*
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* This function is for filesystems to call to implement their readahead
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* address_space operation.
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*
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* Context: The @ops callbacks may submit I/O (eg to read the addresses of
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* blocks from disc), and may wait for it. The caller may be trying to
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* access a different page, and so sleeping excessively should be avoided.
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* It may allocate memory, but should avoid costly allocations. This
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* function is called with memalloc_nofs set, so allocations will not cause
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* the filesystem to be reentered.
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*/
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void iomap_readahead(struct readahead_control *rac, const struct iomap_ops *ops)
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{
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struct iomap_iter iter = {
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.inode = rac->mapping->host,
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.pos = readahead_pos(rac),
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.len = readahead_length(rac),
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};
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struct iomap_readpage_ctx ctx = {
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.rac = rac,
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};
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trace_iomap_readahead(rac->mapping->host, readahead_count(rac));
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while (iomap_iter(&iter, ops) > 0)
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iter.processed = iomap_readahead_iter(&iter, &ctx);
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if (ctx.bio)
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submit_bio(ctx.bio);
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if (ctx.cur_page) {
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if (!ctx.cur_page_in_bio)
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unlock_page(ctx.cur_page);
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put_page(ctx.cur_page);
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}
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}
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EXPORT_SYMBOL_GPL(iomap_readahead);
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/*
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* iomap_is_partially_uptodate checks whether blocks within a page are
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* uptodate or not.
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*
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* Returns true if all blocks which correspond to a file portion
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* we want to read within the page are uptodate.
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*/
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int
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iomap_is_partially_uptodate(struct page *page, unsigned long from,
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unsigned long count)
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{
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struct iomap_page *iop = to_iomap_page(page);
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struct inode *inode = page->mapping->host;
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unsigned len, first, last;
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unsigned i;
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/* Limit range to one page */
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len = min_t(unsigned, PAGE_SIZE - from, count);
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/* First and last blocks in range within page */
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first = from >> inode->i_blkbits;
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last = (from + len - 1) >> inode->i_blkbits;
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if (iop) {
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for (i = first; i <= last; i++)
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if (!test_bit(i, iop->uptodate))
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return 0;
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return 1;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(iomap_is_partially_uptodate);
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int
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iomap_releasepage(struct page *page, gfp_t gfp_mask)
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{
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trace_iomap_releasepage(page->mapping->host, page_offset(page),
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PAGE_SIZE);
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/*
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* mm accommodates an old ext3 case where clean pages might not have had
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* the dirty bit cleared. Thus, it can send actual dirty pages to
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* ->releasepage() via shrink_active_list(); skip those here.
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*/
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if (PageDirty(page) || PageWriteback(page))
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return 0;
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iomap_page_release(page);
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return 1;
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}
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EXPORT_SYMBOL_GPL(iomap_releasepage);
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void
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iomap_invalidatepage(struct page *page, unsigned int offset, unsigned int len)
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{
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trace_iomap_invalidatepage(page->mapping->host, offset, len);
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/*
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|
* If we're invalidating the entire page, clear the dirty state from it
|
|
* and release it to avoid unnecessary buildup of the LRU.
|
|
*/
|
|
if (offset == 0 && len == PAGE_SIZE) {
|
|
WARN_ON_ONCE(PageWriteback(page));
|
|
cancel_dirty_page(page);
|
|
iomap_page_release(page);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(iomap_invalidatepage);
|
|
|
|
#ifdef CONFIG_MIGRATION
|
|
int
|
|
iomap_migrate_page(struct address_space *mapping, struct page *newpage,
|
|
struct page *page, enum migrate_mode mode)
|
|
{
|
|
int ret;
|
|
|
|
ret = migrate_page_move_mapping(mapping, newpage, page, 0);
|
|
if (ret != MIGRATEPAGE_SUCCESS)
|
|
return ret;
|
|
|
|
if (page_has_private(page))
|
|
attach_page_private(newpage, detach_page_private(page));
|
|
|
|
if (mode != MIGRATE_SYNC_NO_COPY)
|
|
migrate_page_copy(newpage, page);
|
|
else
|
|
migrate_page_states(newpage, page);
|
|
return MIGRATEPAGE_SUCCESS;
|
|
}
|
|
EXPORT_SYMBOL_GPL(iomap_migrate_page);
|
|
#endif /* CONFIG_MIGRATION */
|
|
|
|
static void
|
|
iomap_write_failed(struct inode *inode, loff_t pos, unsigned len)
|
|
{
|
|
loff_t i_size = i_size_read(inode);
|
|
|
|
/*
|
|
* Only truncate newly allocated pages beyoned EOF, even if the
|
|
* write started inside the existing inode size.
|
|
*/
|
|
if (pos + len > i_size)
|
|
truncate_pagecache_range(inode, max(pos, i_size), pos + len);
|
|
}
|
|
|
|
static int
|
|
iomap_read_page_sync(loff_t block_start, struct page *page, unsigned poff,
|
|
unsigned plen, const struct iomap *iomap)
|
|
{
|
|
struct bio_vec bvec;
|
|
struct bio bio;
|
|
|
|
bio_init(&bio, &bvec, 1);
|
|
bio.bi_opf = REQ_OP_READ;
|
|
bio.bi_iter.bi_sector = iomap_sector(iomap, block_start);
|
|
bio_set_dev(&bio, iomap->bdev);
|
|
__bio_add_page(&bio, page, plen, poff);
|
|
return submit_bio_wait(&bio);
|
|
}
|
|
|
|
static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
|
|
unsigned len, struct page *page)
|
|
{
|
|
const struct iomap *srcmap = iomap_iter_srcmap(iter);
|
|
struct iomap_page *iop = iomap_page_create(iter->inode, page);
|
|
loff_t block_size = i_blocksize(iter->inode);
|
|
loff_t block_start = round_down(pos, block_size);
|
|
loff_t block_end = round_up(pos + len, block_size);
|
|
unsigned from = offset_in_page(pos), to = from + len, poff, plen;
|
|
|
|
if (PageUptodate(page))
|
|
return 0;
|
|
ClearPageError(page);
|
|
|
|
do {
|
|
iomap_adjust_read_range(iter->inode, iop, &block_start,
|
|
block_end - block_start, &poff, &plen);
|
|
if (plen == 0)
|
|
break;
|
|
|
|
if (!(iter->flags & IOMAP_UNSHARE) &&
|
|
(from <= poff || from >= poff + plen) &&
|
|
(to <= poff || to >= poff + plen))
|
|
continue;
|
|
|
|
if (iomap_block_needs_zeroing(iter, block_start)) {
|
|
if (WARN_ON_ONCE(iter->flags & IOMAP_UNSHARE))
|
|
return -EIO;
|
|
zero_user_segments(page, poff, from, to, poff + plen);
|
|
} else {
|
|
int status = iomap_read_page_sync(block_start, page,
|
|
poff, plen, srcmap);
|
|
if (status)
|
|
return status;
|
|
}
|
|
iomap_set_range_uptodate(page, poff, plen);
|
|
} while ((block_start += plen) < block_end);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int iomap_write_begin_inline(const struct iomap_iter *iter,
|
|
struct page *page)
|
|
{
|
|
/* needs more work for the tailpacking case; disable for now */
|
|
if (WARN_ON_ONCE(iomap_iter_srcmap(iter)->offset != 0))
|
|
return -EIO;
|
|
return iomap_read_inline_data(iter, page);
|
|
}
|
|
|
|
static int iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
|
|
unsigned len, struct page **pagep)
|
|
{
|
|
const struct iomap_page_ops *page_ops = iter->iomap.page_ops;
|
|
const struct iomap *srcmap = iomap_iter_srcmap(iter);
|
|
struct page *page;
|
|
int status = 0;
|
|
|
|
BUG_ON(pos + len > iter->iomap.offset + iter->iomap.length);
|
|
if (srcmap != &iter->iomap)
|
|
BUG_ON(pos + len > srcmap->offset + srcmap->length);
|
|
|
|
if (fatal_signal_pending(current))
|
|
return -EINTR;
|
|
|
|
if (page_ops && page_ops->page_prepare) {
|
|
status = page_ops->page_prepare(iter->inode, pos, len);
|
|
if (status)
|
|
return status;
|
|
}
|
|
|
|
page = grab_cache_page_write_begin(iter->inode->i_mapping,
|
|
pos >> PAGE_SHIFT, AOP_FLAG_NOFS);
|
|
if (!page) {
|
|
status = -ENOMEM;
|
|
goto out_no_page;
|
|
}
|
|
|
|
if (srcmap->type == IOMAP_INLINE)
|
|
status = iomap_write_begin_inline(iter, page);
|
|
else if (srcmap->flags & IOMAP_F_BUFFER_HEAD)
|
|
status = __block_write_begin_int(page, pos, len, NULL, srcmap);
|
|
else
|
|
status = __iomap_write_begin(iter, pos, len, page);
|
|
|
|
if (unlikely(status))
|
|
goto out_unlock;
|
|
|
|
*pagep = page;
|
|
return 0;
|
|
|
|
out_unlock:
|
|
unlock_page(page);
|
|
put_page(page);
|
|
iomap_write_failed(iter->inode, pos, len);
|
|
|
|
out_no_page:
|
|
if (page_ops && page_ops->page_done)
|
|
page_ops->page_done(iter->inode, pos, 0, NULL);
|
|
return status;
|
|
}
|
|
|
|
static size_t __iomap_write_end(struct inode *inode, loff_t pos, size_t len,
|
|
size_t copied, struct page *page)
|
|
{
|
|
flush_dcache_page(page);
|
|
|
|
/*
|
|
* The blocks that were entirely written will now be uptodate, so we
|
|
* don't have to worry about a readpage reading them and overwriting a
|
|
* partial write. However, if we've encountered a short write and only
|
|
* partially written into a block, it will not be marked uptodate, so a
|
|
* readpage might come in and destroy our partial write.
|
|
*
|
|
* Do the simplest thing and just treat any short write to a
|
|
* non-uptodate page as a zero-length write, and force the caller to
|
|
* redo the whole thing.
|
|
*/
|
|
if (unlikely(copied < len && !PageUptodate(page)))
|
|
return 0;
|
|
iomap_set_range_uptodate(page, offset_in_page(pos), len);
|
|
__set_page_dirty_nobuffers(page);
|
|
return copied;
|
|
}
|
|
|
|
static size_t iomap_write_end_inline(const struct iomap_iter *iter,
|
|
struct page *page, loff_t pos, size_t copied)
|
|
{
|
|
const struct iomap *iomap = &iter->iomap;
|
|
void *addr;
|
|
|
|
WARN_ON_ONCE(!PageUptodate(page));
|
|
BUG_ON(!iomap_inline_data_valid(iomap));
|
|
|
|
flush_dcache_page(page);
|
|
addr = kmap_local_page(page) + pos;
|
|
memcpy(iomap_inline_data(iomap, pos), addr, copied);
|
|
kunmap_local(addr);
|
|
|
|
mark_inode_dirty(iter->inode);
|
|
return copied;
|
|
}
|
|
|
|
/* Returns the number of bytes copied. May be 0. Cannot be an errno. */
|
|
static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
|
|
size_t copied, struct page *page)
|
|
{
|
|
const struct iomap_page_ops *page_ops = iter->iomap.page_ops;
|
|
const struct iomap *srcmap = iomap_iter_srcmap(iter);
|
|
loff_t old_size = iter->inode->i_size;
|
|
size_t ret;
|
|
|
|
if (srcmap->type == IOMAP_INLINE) {
|
|
ret = iomap_write_end_inline(iter, page, pos, copied);
|
|
} else if (srcmap->flags & IOMAP_F_BUFFER_HEAD) {
|
|
ret = block_write_end(NULL, iter->inode->i_mapping, pos, len,
|
|
copied, page, NULL);
|
|
} else {
|
|
ret = __iomap_write_end(iter->inode, pos, len, copied, page);
|
|
}
|
|
|
|
/*
|
|
* Update the in-memory inode size after copying the data into the page
|
|
* cache. It's up to the file system to write the updated size to disk,
|
|
* preferably after I/O completion so that no stale data is exposed.
|
|
*/
|
|
if (pos + ret > old_size) {
|
|
i_size_write(iter->inode, pos + ret);
|
|
iter->iomap.flags |= IOMAP_F_SIZE_CHANGED;
|
|
}
|
|
unlock_page(page);
|
|
|
|
if (old_size < pos)
|
|
pagecache_isize_extended(iter->inode, old_size, pos);
|
|
if (page_ops && page_ops->page_done)
|
|
page_ops->page_done(iter->inode, pos, ret, page);
|
|
put_page(page);
|
|
|
|
if (ret < len)
|
|
iomap_write_failed(iter->inode, pos, len);
|
|
return ret;
|
|
}
|
|
|
|
static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
|
|
{
|
|
loff_t length = iomap_length(iter);
|
|
loff_t pos = iter->pos;
|
|
ssize_t written = 0;
|
|
long status = 0;
|
|
|
|
do {
|
|
struct page *page;
|
|
unsigned long offset; /* Offset into pagecache page */
|
|
unsigned long bytes; /* Bytes to write to page */
|
|
size_t copied; /* Bytes copied from user */
|
|
|
|
offset = offset_in_page(pos);
|
|
bytes = min_t(unsigned long, PAGE_SIZE - offset,
|
|
iov_iter_count(i));
|
|
again:
|
|
if (bytes > length)
|
|
bytes = length;
|
|
|
|
/*
|
|
* Bring in the user page that we'll copy from _first_.
|
|
* Otherwise there's a nasty deadlock on copying from the
|
|
* same page as we're writing to, without it being marked
|
|
* up-to-date.
|
|
*/
|
|
if (unlikely(fault_in_iov_iter_readable(i, bytes))) {
|
|
status = -EFAULT;
|
|
break;
|
|
}
|
|
|
|
status = iomap_write_begin(iter, pos, bytes, &page);
|
|
if (unlikely(status))
|
|
break;
|
|
|
|
if (mapping_writably_mapped(iter->inode->i_mapping))
|
|
flush_dcache_page(page);
|
|
|
|
copied = copy_page_from_iter_atomic(page, offset, bytes, i);
|
|
|
|
status = iomap_write_end(iter, pos, bytes, copied, page);
|
|
|
|
if (unlikely(copied != status))
|
|
iov_iter_revert(i, copied - status);
|
|
|
|
cond_resched();
|
|
if (unlikely(status == 0)) {
|
|
/*
|
|
* A short copy made iomap_write_end() reject the
|
|
* thing entirely. Might be memory poisoning
|
|
* halfway through, might be a race with munmap,
|
|
* might be severe memory pressure.
|
|
*/
|
|
if (copied)
|
|
bytes = copied;
|
|
goto again;
|
|
}
|
|
pos += status;
|
|
written += status;
|
|
length -= status;
|
|
|
|
balance_dirty_pages_ratelimited(iter->inode->i_mapping);
|
|
} while (iov_iter_count(i) && length);
|
|
|
|
return written ? written : status;
|
|
}
|
|
|
|
ssize_t
|
|
iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i,
|
|
const struct iomap_ops *ops)
|
|
{
|
|
struct iomap_iter iter = {
|
|
.inode = iocb->ki_filp->f_mapping->host,
|
|
.pos = iocb->ki_pos,
|
|
.len = iov_iter_count(i),
|
|
.flags = IOMAP_WRITE,
|
|
};
|
|
int ret;
|
|
|
|
while ((ret = iomap_iter(&iter, ops)) > 0)
|
|
iter.processed = iomap_write_iter(&iter, i);
|
|
if (iter.pos == iocb->ki_pos)
|
|
return ret;
|
|
return iter.pos - iocb->ki_pos;
|
|
}
|
|
EXPORT_SYMBOL_GPL(iomap_file_buffered_write);
|
|
|
|
static loff_t iomap_unshare_iter(struct iomap_iter *iter)
|
|
{
|
|
struct iomap *iomap = &iter->iomap;
|
|
const struct iomap *srcmap = iomap_iter_srcmap(iter);
|
|
loff_t pos = iter->pos;
|
|
loff_t length = iomap_length(iter);
|
|
long status = 0;
|
|
loff_t written = 0;
|
|
|
|
/* don't bother with blocks that are not shared to start with */
|
|
if (!(iomap->flags & IOMAP_F_SHARED))
|
|
return length;
|
|
/* don't bother with holes or unwritten extents */
|
|
if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN)
|
|
return length;
|
|
|
|
do {
|
|
unsigned long offset = offset_in_page(pos);
|
|
unsigned long bytes = min_t(loff_t, PAGE_SIZE - offset, length);
|
|
struct page *page;
|
|
|
|
status = iomap_write_begin(iter, pos, bytes, &page);
|
|
if (unlikely(status))
|
|
return status;
|
|
|
|
status = iomap_write_end(iter, pos, bytes, bytes, page);
|
|
if (WARN_ON_ONCE(status == 0))
|
|
return -EIO;
|
|
|
|
cond_resched();
|
|
|
|
pos += status;
|
|
written += status;
|
|
length -= status;
|
|
|
|
balance_dirty_pages_ratelimited(iter->inode->i_mapping);
|
|
} while (length);
|
|
|
|
return written;
|
|
}
|
|
|
|
int
|
|
iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len,
|
|
const struct iomap_ops *ops)
|
|
{
|
|
struct iomap_iter iter = {
|
|
.inode = inode,
|
|
.pos = pos,
|
|
.len = len,
|
|
.flags = IOMAP_WRITE | IOMAP_UNSHARE,
|
|
};
|
|
int ret;
|
|
|
|
while ((ret = iomap_iter(&iter, ops)) > 0)
|
|
iter.processed = iomap_unshare_iter(&iter);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(iomap_file_unshare);
|
|
|
|
static s64 __iomap_zero_iter(struct iomap_iter *iter, loff_t pos, u64 length)
|
|
{
|
|
struct page *page;
|
|
int status;
|
|
unsigned offset = offset_in_page(pos);
|
|
unsigned bytes = min_t(u64, PAGE_SIZE - offset, length);
|
|
|
|
status = iomap_write_begin(iter, pos, bytes, &page);
|
|
if (status)
|
|
return status;
|
|
|
|
zero_user(page, offset, bytes);
|
|
mark_page_accessed(page);
|
|
|
|
return iomap_write_end(iter, pos, bytes, bytes, page);
|
|
}
|
|
|
|
static loff_t iomap_zero_iter(struct iomap_iter *iter, bool *did_zero)
|
|
{
|
|
struct iomap *iomap = &iter->iomap;
|
|
const struct iomap *srcmap = iomap_iter_srcmap(iter);
|
|
loff_t pos = iter->pos;
|
|
loff_t length = iomap_length(iter);
|
|
loff_t written = 0;
|
|
|
|
/* already zeroed? we're done. */
|
|
if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN)
|
|
return length;
|
|
|
|
do {
|
|
s64 bytes;
|
|
|
|
if (IS_DAX(iter->inode))
|
|
bytes = dax_iomap_zero(pos, length, iomap);
|
|
else
|
|
bytes = __iomap_zero_iter(iter, pos, length);
|
|
if (bytes < 0)
|
|
return bytes;
|
|
|
|
pos += bytes;
|
|
length -= bytes;
|
|
written += bytes;
|
|
if (did_zero)
|
|
*did_zero = true;
|
|
} while (length > 0);
|
|
|
|
return written;
|
|
}
|
|
|
|
int
|
|
iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
|
|
const struct iomap_ops *ops)
|
|
{
|
|
struct iomap_iter iter = {
|
|
.inode = inode,
|
|
.pos = pos,
|
|
.len = len,
|
|
.flags = IOMAP_ZERO,
|
|
};
|
|
int ret;
|
|
|
|
while ((ret = iomap_iter(&iter, ops)) > 0)
|
|
iter.processed = iomap_zero_iter(&iter, did_zero);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(iomap_zero_range);
|
|
|
|
int
|
|
iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero,
|
|
const struct iomap_ops *ops)
|
|
{
|
|
unsigned int blocksize = i_blocksize(inode);
|
|
unsigned int off = pos & (blocksize - 1);
|
|
|
|
/* Block boundary? Nothing to do */
|
|
if (!off)
|
|
return 0;
|
|
return iomap_zero_range(inode, pos, blocksize - off, did_zero, ops);
|
|
}
|
|
EXPORT_SYMBOL_GPL(iomap_truncate_page);
|
|
|
|
static loff_t iomap_page_mkwrite_iter(struct iomap_iter *iter,
|
|
struct page *page)
|
|
{
|
|
loff_t length = iomap_length(iter);
|
|
int ret;
|
|
|
|
if (iter->iomap.flags & IOMAP_F_BUFFER_HEAD) {
|
|
ret = __block_write_begin_int(page, iter->pos, length, NULL,
|
|
&iter->iomap);
|
|
if (ret)
|
|
return ret;
|
|
block_commit_write(page, 0, length);
|
|
} else {
|
|
WARN_ON_ONCE(!PageUptodate(page));
|
|
set_page_dirty(page);
|
|
}
|
|
|
|
return length;
|
|
}
|
|
|
|
vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops)
|
|
{
|
|
struct iomap_iter iter = {
|
|
.inode = file_inode(vmf->vma->vm_file),
|
|
.flags = IOMAP_WRITE | IOMAP_FAULT,
|
|
};
|
|
struct page *page = vmf->page;
|
|
ssize_t ret;
|
|
|
|
lock_page(page);
|
|
ret = page_mkwrite_check_truncate(page, iter.inode);
|
|
if (ret < 0)
|
|
goto out_unlock;
|
|
iter.pos = page_offset(page);
|
|
iter.len = ret;
|
|
while ((ret = iomap_iter(&iter, ops)) > 0)
|
|
iter.processed = iomap_page_mkwrite_iter(&iter, page);
|
|
|
|
if (ret < 0)
|
|
goto out_unlock;
|
|
wait_for_stable_page(page);
|
|
return VM_FAULT_LOCKED;
|
|
out_unlock:
|
|
unlock_page(page);
|
|
return block_page_mkwrite_return(ret);
|
|
}
|
|
EXPORT_SYMBOL_GPL(iomap_page_mkwrite);
|
|
|
|
static void
|
|
iomap_finish_page_writeback(struct inode *inode, struct page *page,
|
|
int error, unsigned int len)
|
|
{
|
|
struct iomap_page *iop = to_iomap_page(page);
|
|
|
|
if (error) {
|
|
SetPageError(page);
|
|
mapping_set_error(inode->i_mapping, error);
|
|
}
|
|
|
|
WARN_ON_ONCE(i_blocks_per_page(inode, page) > 1 && !iop);
|
|
WARN_ON_ONCE(iop && atomic_read(&iop->write_bytes_pending) <= 0);
|
|
|
|
if (!iop || atomic_sub_and_test(len, &iop->write_bytes_pending))
|
|
end_page_writeback(page);
|
|
}
|
|
|
|
/*
|
|
* We're now finished for good with this ioend structure. Update the page
|
|
* state, release holds on bios, and finally free up memory. Do not use the
|
|
* ioend after this.
|
|
*/
|
|
static void
|
|
iomap_finish_ioend(struct iomap_ioend *ioend, int error)
|
|
{
|
|
struct inode *inode = ioend->io_inode;
|
|
struct bio *bio = &ioend->io_inline_bio;
|
|
struct bio *last = ioend->io_bio, *next;
|
|
u64 start = bio->bi_iter.bi_sector;
|
|
loff_t offset = ioend->io_offset;
|
|
bool quiet = bio_flagged(bio, BIO_QUIET);
|
|
|
|
for (bio = &ioend->io_inline_bio; bio; bio = next) {
|
|
struct bio_vec *bv;
|
|
struct bvec_iter_all iter_all;
|
|
|
|
/*
|
|
* For the last bio, bi_private points to the ioend, so we
|
|
* need to explicitly end the iteration here.
|
|
*/
|
|
if (bio == last)
|
|
next = NULL;
|
|
else
|
|
next = bio->bi_private;
|
|
|
|
/* walk each page on bio, ending page IO on them */
|
|
bio_for_each_segment_all(bv, bio, iter_all)
|
|
iomap_finish_page_writeback(inode, bv->bv_page, error,
|
|
bv->bv_len);
|
|
bio_put(bio);
|
|
}
|
|
/* The ioend has been freed by bio_put() */
|
|
|
|
if (unlikely(error && !quiet)) {
|
|
printk_ratelimited(KERN_ERR
|
|
"%s: writeback error on inode %lu, offset %lld, sector %llu",
|
|
inode->i_sb->s_id, inode->i_ino, offset, start);
|
|
}
|
|
}
|
|
|
|
void
|
|
iomap_finish_ioends(struct iomap_ioend *ioend, int error)
|
|
{
|
|
struct list_head tmp;
|
|
|
|
list_replace_init(&ioend->io_list, &tmp);
|
|
iomap_finish_ioend(ioend, error);
|
|
|
|
while (!list_empty(&tmp)) {
|
|
ioend = list_first_entry(&tmp, struct iomap_ioend, io_list);
|
|
list_del_init(&ioend->io_list);
|
|
iomap_finish_ioend(ioend, error);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(iomap_finish_ioends);
|
|
|
|
/*
|
|
* We can merge two adjacent ioends if they have the same set of work to do.
|
|
*/
|
|
static bool
|
|
iomap_ioend_can_merge(struct iomap_ioend *ioend, struct iomap_ioend *next)
|
|
{
|
|
if (ioend->io_bio->bi_status != next->io_bio->bi_status)
|
|
return false;
|
|
if ((ioend->io_flags & IOMAP_F_SHARED) ^
|
|
(next->io_flags & IOMAP_F_SHARED))
|
|
return false;
|
|
if ((ioend->io_type == IOMAP_UNWRITTEN) ^
|
|
(next->io_type == IOMAP_UNWRITTEN))
|
|
return false;
|
|
if (ioend->io_offset + ioend->io_size != next->io_offset)
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
void
|
|
iomap_ioend_try_merge(struct iomap_ioend *ioend, struct list_head *more_ioends)
|
|
{
|
|
struct iomap_ioend *next;
|
|
|
|
INIT_LIST_HEAD(&ioend->io_list);
|
|
|
|
while ((next = list_first_entry_or_null(more_ioends, struct iomap_ioend,
|
|
io_list))) {
|
|
if (!iomap_ioend_can_merge(ioend, next))
|
|
break;
|
|
list_move_tail(&next->io_list, &ioend->io_list);
|
|
ioend->io_size += next->io_size;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(iomap_ioend_try_merge);
|
|
|
|
static int
|
|
iomap_ioend_compare(void *priv, const struct list_head *a,
|
|
const struct list_head *b)
|
|
{
|
|
struct iomap_ioend *ia = container_of(a, struct iomap_ioend, io_list);
|
|
struct iomap_ioend *ib = container_of(b, struct iomap_ioend, io_list);
|
|
|
|
if (ia->io_offset < ib->io_offset)
|
|
return -1;
|
|
if (ia->io_offset > ib->io_offset)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
void
|
|
iomap_sort_ioends(struct list_head *ioend_list)
|
|
{
|
|
list_sort(NULL, ioend_list, iomap_ioend_compare);
|
|
}
|
|
EXPORT_SYMBOL_GPL(iomap_sort_ioends);
|
|
|
|
static void iomap_writepage_end_bio(struct bio *bio)
|
|
{
|
|
struct iomap_ioend *ioend = bio->bi_private;
|
|
|
|
iomap_finish_ioend(ioend, blk_status_to_errno(bio->bi_status));
|
|
}
|
|
|
|
/*
|
|
* Submit the final bio for an ioend.
|
|
*
|
|
* If @error is non-zero, it means that we have a situation where some part of
|
|
* the submission process has failed after we've marked pages for writeback
|
|
* and unlocked them. In this situation, we need to fail the bio instead of
|
|
* submitting it. This typically only happens on a filesystem shutdown.
|
|
*/
|
|
static int
|
|
iomap_submit_ioend(struct iomap_writepage_ctx *wpc, struct iomap_ioend *ioend,
|
|
int error)
|
|
{
|
|
ioend->io_bio->bi_private = ioend;
|
|
ioend->io_bio->bi_end_io = iomap_writepage_end_bio;
|
|
|
|
if (wpc->ops->prepare_ioend)
|
|
error = wpc->ops->prepare_ioend(ioend, error);
|
|
if (error) {
|
|
/*
|
|
* If we're failing the IO now, just mark the ioend with an
|
|
* error and finish it. This will run IO completion immediately
|
|
* as there is only one reference to the ioend at this point in
|
|
* time.
|
|
*/
|
|
ioend->io_bio->bi_status = errno_to_blk_status(error);
|
|
bio_endio(ioend->io_bio);
|
|
return error;
|
|
}
|
|
|
|
submit_bio(ioend->io_bio);
|
|
return 0;
|
|
}
|
|
|
|
static struct iomap_ioend *
|
|
iomap_alloc_ioend(struct inode *inode, struct iomap_writepage_ctx *wpc,
|
|
loff_t offset, sector_t sector, struct writeback_control *wbc)
|
|
{
|
|
struct iomap_ioend *ioend;
|
|
struct bio *bio;
|
|
|
|
bio = bio_alloc_bioset(GFP_NOFS, BIO_MAX_VECS, &iomap_ioend_bioset);
|
|
bio_set_dev(bio, wpc->iomap.bdev);
|
|
bio->bi_iter.bi_sector = sector;
|
|
bio->bi_opf = REQ_OP_WRITE | wbc_to_write_flags(wbc);
|
|
bio->bi_write_hint = inode->i_write_hint;
|
|
wbc_init_bio(wbc, bio);
|
|
|
|
ioend = container_of(bio, struct iomap_ioend, io_inline_bio);
|
|
INIT_LIST_HEAD(&ioend->io_list);
|
|
ioend->io_type = wpc->iomap.type;
|
|
ioend->io_flags = wpc->iomap.flags;
|
|
ioend->io_inode = inode;
|
|
ioend->io_size = 0;
|
|
ioend->io_offset = offset;
|
|
ioend->io_bio = bio;
|
|
return ioend;
|
|
}
|
|
|
|
/*
|
|
* Allocate a new bio, and chain the old bio to the new one.
|
|
*
|
|
* Note that we have to perform the chaining in this unintuitive order
|
|
* so that the bi_private linkage is set up in the right direction for the
|
|
* traversal in iomap_finish_ioend().
|
|
*/
|
|
static struct bio *
|
|
iomap_chain_bio(struct bio *prev)
|
|
{
|
|
struct bio *new;
|
|
|
|
new = bio_alloc(GFP_NOFS, BIO_MAX_VECS);
|
|
bio_copy_dev(new, prev);/* also copies over blkcg information */
|
|
new->bi_iter.bi_sector = bio_end_sector(prev);
|
|
new->bi_opf = prev->bi_opf;
|
|
new->bi_write_hint = prev->bi_write_hint;
|
|
|
|
bio_chain(prev, new);
|
|
bio_get(prev); /* for iomap_finish_ioend */
|
|
submit_bio(prev);
|
|
return new;
|
|
}
|
|
|
|
static bool
|
|
iomap_can_add_to_ioend(struct iomap_writepage_ctx *wpc, loff_t offset,
|
|
sector_t sector)
|
|
{
|
|
if ((wpc->iomap.flags & IOMAP_F_SHARED) !=
|
|
(wpc->ioend->io_flags & IOMAP_F_SHARED))
|
|
return false;
|
|
if (wpc->iomap.type != wpc->ioend->io_type)
|
|
return false;
|
|
if (offset != wpc->ioend->io_offset + wpc->ioend->io_size)
|
|
return false;
|
|
if (sector != bio_end_sector(wpc->ioend->io_bio))
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Test to see if we have an existing ioend structure that we could append to
|
|
* first; otherwise finish off the current ioend and start another.
|
|
*/
|
|
static void
|
|
iomap_add_to_ioend(struct inode *inode, loff_t offset, struct page *page,
|
|
struct iomap_page *iop, struct iomap_writepage_ctx *wpc,
|
|
struct writeback_control *wbc, struct list_head *iolist)
|
|
{
|
|
sector_t sector = iomap_sector(&wpc->iomap, offset);
|
|
unsigned len = i_blocksize(inode);
|
|
unsigned poff = offset & (PAGE_SIZE - 1);
|
|
|
|
if (!wpc->ioend || !iomap_can_add_to_ioend(wpc, offset, sector)) {
|
|
if (wpc->ioend)
|
|
list_add(&wpc->ioend->io_list, iolist);
|
|
wpc->ioend = iomap_alloc_ioend(inode, wpc, offset, sector, wbc);
|
|
}
|
|
|
|
if (bio_add_page(wpc->ioend->io_bio, page, len, poff) != len) {
|
|
wpc->ioend->io_bio = iomap_chain_bio(wpc->ioend->io_bio);
|
|
__bio_add_page(wpc->ioend->io_bio, page, len, poff);
|
|
}
|
|
|
|
if (iop)
|
|
atomic_add(len, &iop->write_bytes_pending);
|
|
wpc->ioend->io_size += len;
|
|
wbc_account_cgroup_owner(wbc, page, len);
|
|
}
|
|
|
|
/*
|
|
* We implement an immediate ioend submission policy here to avoid needing to
|
|
* chain multiple ioends and hence nest mempool allocations which can violate
|
|
* the forward progress guarantees we need to provide. The current ioend we're
|
|
* adding blocks to is cached in the writepage context, and if the new block
|
|
* doesn't append to the cached ioend, it will create a new ioend and cache that
|
|
* instead.
|
|
*
|
|
* If a new ioend is created and cached, the old ioend is returned and queued
|
|
* locally for submission once the entire page is processed or an error has been
|
|
* detected. While ioends are submitted immediately after they are completed,
|
|
* batching optimisations are provided by higher level block plugging.
|
|
*
|
|
* At the end of a writeback pass, there will be a cached ioend remaining on the
|
|
* writepage context that the caller will need to submit.
|
|
*/
|
|
static int
|
|
iomap_writepage_map(struct iomap_writepage_ctx *wpc,
|
|
struct writeback_control *wbc, struct inode *inode,
|
|
struct page *page, u64 end_offset)
|
|
{
|
|
struct iomap_page *iop = iomap_page_create(inode, page);
|
|
struct iomap_ioend *ioend, *next;
|
|
unsigned len = i_blocksize(inode);
|
|
u64 file_offset; /* file offset of page */
|
|
int error = 0, count = 0, i;
|
|
LIST_HEAD(submit_list);
|
|
|
|
WARN_ON_ONCE(iop && atomic_read(&iop->write_bytes_pending) != 0);
|
|
|
|
/*
|
|
* Walk through the page to find areas to write back. If we run off the
|
|
* end of the current map or find the current map invalid, grab a new
|
|
* one.
|
|
*/
|
|
for (i = 0, file_offset = page_offset(page);
|
|
i < (PAGE_SIZE >> inode->i_blkbits) && file_offset < end_offset;
|
|
i++, file_offset += len) {
|
|
if (iop && !test_bit(i, iop->uptodate))
|
|
continue;
|
|
|
|
error = wpc->ops->map_blocks(wpc, inode, file_offset);
|
|
if (error)
|
|
break;
|
|
if (WARN_ON_ONCE(wpc->iomap.type == IOMAP_INLINE))
|
|
continue;
|
|
if (wpc->iomap.type == IOMAP_HOLE)
|
|
continue;
|
|
iomap_add_to_ioend(inode, file_offset, page, iop, wpc, wbc,
|
|
&submit_list);
|
|
count++;
|
|
}
|
|
|
|
WARN_ON_ONCE(!wpc->ioend && !list_empty(&submit_list));
|
|
WARN_ON_ONCE(!PageLocked(page));
|
|
WARN_ON_ONCE(PageWriteback(page));
|
|
WARN_ON_ONCE(PageDirty(page));
|
|
|
|
/*
|
|
* We cannot cancel the ioend directly here on error. We may have
|
|
* already set other pages under writeback and hence we have to run I/O
|
|
* completion to mark the error state of the pages under writeback
|
|
* appropriately.
|
|
*/
|
|
if (unlikely(error)) {
|
|
/*
|
|
* Let the filesystem know what portion of the current page
|
|
* failed to map. If the page hasn't been added to ioend, it
|
|
* won't be affected by I/O completion and we must unlock it
|
|
* now.
|
|
*/
|
|
if (wpc->ops->discard_page)
|
|
wpc->ops->discard_page(page, file_offset);
|
|
if (!count) {
|
|
ClearPageUptodate(page);
|
|
unlock_page(page);
|
|
goto done;
|
|
}
|
|
}
|
|
|
|
set_page_writeback(page);
|
|
unlock_page(page);
|
|
|
|
/*
|
|
* Preserve the original error if there was one; catch
|
|
* submission errors here and propagate into subsequent ioend
|
|
* submissions.
|
|
*/
|
|
list_for_each_entry_safe(ioend, next, &submit_list, io_list) {
|
|
int error2;
|
|
|
|
list_del_init(&ioend->io_list);
|
|
error2 = iomap_submit_ioend(wpc, ioend, error);
|
|
if (error2 && !error)
|
|
error = error2;
|
|
}
|
|
|
|
/*
|
|
* We can end up here with no error and nothing to write only if we race
|
|
* with a partial page truncate on a sub-page block sized filesystem.
|
|
*/
|
|
if (!count)
|
|
end_page_writeback(page);
|
|
done:
|
|
mapping_set_error(page->mapping, error);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Write out a dirty page.
|
|
*
|
|
* For delalloc space on the page, we need to allocate space and flush it.
|
|
* For unwritten space on the page, we need to start the conversion to
|
|
* regular allocated space.
|
|
*/
|
|
static int
|
|
iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
|
|
{
|
|
struct iomap_writepage_ctx *wpc = data;
|
|
struct inode *inode = page->mapping->host;
|
|
pgoff_t end_index;
|
|
u64 end_offset;
|
|
loff_t offset;
|
|
|
|
trace_iomap_writepage(inode, page_offset(page), PAGE_SIZE);
|
|
|
|
/*
|
|
* Refuse to write the page out if we're called from reclaim context.
|
|
*
|
|
* This avoids stack overflows when called from deeply used stacks in
|
|
* random callers for direct reclaim or memcg reclaim. We explicitly
|
|
* allow reclaim from kswapd as the stack usage there is relatively low.
|
|
*
|
|
* This should never happen except in the case of a VM regression so
|
|
* warn about it.
|
|
*/
|
|
if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) ==
|
|
PF_MEMALLOC))
|
|
goto redirty;
|
|
|
|
/*
|
|
* Is this page beyond the end of the file?
|
|
*
|
|
* The page index is less than the end_index, adjust the end_offset
|
|
* to the highest offset that this page should represent.
|
|
* -----------------------------------------------------
|
|
* | file mapping | <EOF> |
|
|
* -----------------------------------------------------
|
|
* | Page ... | Page N-2 | Page N-1 | Page N | |
|
|
* ^--------------------------------^----------|--------
|
|
* | desired writeback range | see else |
|
|
* ---------------------------------^------------------|
|
|
*/
|
|
offset = i_size_read(inode);
|
|
end_index = offset >> PAGE_SHIFT;
|
|
if (page->index < end_index)
|
|
end_offset = (loff_t)(page->index + 1) << PAGE_SHIFT;
|
|
else {
|
|
/*
|
|
* Check whether the page to write out is beyond or straddles
|
|
* i_size or not.
|
|
* -------------------------------------------------------
|
|
* | file mapping | <EOF> |
|
|
* -------------------------------------------------------
|
|
* | Page ... | Page N-2 | Page N-1 | Page N | Beyond |
|
|
* ^--------------------------------^-----------|---------
|
|
* | | Straddles |
|
|
* ---------------------------------^-----------|--------|
|
|
*/
|
|
unsigned offset_into_page = offset & (PAGE_SIZE - 1);
|
|
|
|
/*
|
|
* Skip the page if it's fully outside i_size, e.g. due to a
|
|
* truncate operation that's in progress. We must redirty the
|
|
* page so that reclaim stops reclaiming it. Otherwise
|
|
* iomap_vm_releasepage() is called on it and gets confused.
|
|
*
|
|
* Note that the end_index is unsigned long. If the given
|
|
* offset is greater than 16TB on a 32-bit system then if we
|
|
* checked if the page is fully outside i_size with
|
|
* "if (page->index >= end_index + 1)", "end_index + 1" would
|
|
* overflow and evaluate to 0. Hence this page would be
|
|
* redirtied and written out repeatedly, which would result in
|
|
* an infinite loop; the user program performing this operation
|
|
* would hang. Instead, we can detect this situation by
|
|
* checking if the page is totally beyond i_size or if its
|
|
* offset is just equal to the EOF.
|
|
*/
|
|
if (page->index > end_index ||
|
|
(page->index == end_index && offset_into_page == 0))
|
|
goto redirty;
|
|
|
|
/*
|
|
* The page straddles i_size. It must be zeroed out on each
|
|
* and every writepage invocation because it may be mmapped.
|
|
* "A file is mapped in multiples of the page size. For a file
|
|
* that is not a multiple of the page size, the remaining
|
|
* memory is zeroed when mapped, and writes to that region are
|
|
* not written out to the file."
|
|
*/
|
|
zero_user_segment(page, offset_into_page, PAGE_SIZE);
|
|
|
|
/* Adjust the end_offset to the end of file */
|
|
end_offset = offset;
|
|
}
|
|
|
|
return iomap_writepage_map(wpc, wbc, inode, page, end_offset);
|
|
|
|
redirty:
|
|
redirty_page_for_writepage(wbc, page);
|
|
unlock_page(page);
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
iomap_writepage(struct page *page, struct writeback_control *wbc,
|
|
struct iomap_writepage_ctx *wpc,
|
|
const struct iomap_writeback_ops *ops)
|
|
{
|
|
int ret;
|
|
|
|
wpc->ops = ops;
|
|
ret = iomap_do_writepage(page, wbc, wpc);
|
|
if (!wpc->ioend)
|
|
return ret;
|
|
return iomap_submit_ioend(wpc, wpc->ioend, ret);
|
|
}
|
|
EXPORT_SYMBOL_GPL(iomap_writepage);
|
|
|
|
int
|
|
iomap_writepages(struct address_space *mapping, struct writeback_control *wbc,
|
|
struct iomap_writepage_ctx *wpc,
|
|
const struct iomap_writeback_ops *ops)
|
|
{
|
|
int ret;
|
|
|
|
wpc->ops = ops;
|
|
ret = write_cache_pages(mapping, wbc, iomap_do_writepage, wpc);
|
|
if (!wpc->ioend)
|
|
return ret;
|
|
return iomap_submit_ioend(wpc, wpc->ioend, ret);
|
|
}
|
|
EXPORT_SYMBOL_GPL(iomap_writepages);
|
|
|
|
static int __init iomap_init(void)
|
|
{
|
|
return bioset_init(&iomap_ioend_bioset, 4 * (PAGE_SIZE / SECTOR_SIZE),
|
|
offsetof(struct iomap_ioend, io_inline_bio),
|
|
BIOSET_NEED_BVECS);
|
|
}
|
|
fs_initcall(iomap_init);
|