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1571 lines
42 KiB
1571 lines
42 KiB
// 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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|
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#include "../internal.h" |
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|
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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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|
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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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|
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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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|
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static struct bio_set iomap_ioend_bioset; |
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|
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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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|
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if (iop || nr_blocks <= 1) |
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return iop; |
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|
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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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|
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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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|
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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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/* |
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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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/* |
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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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|
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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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/* |
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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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|
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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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|
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*offp = poff; |
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*lenp = plen; |
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} |
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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static void |
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iomap_read_inline_data(struct inode *inode, struct page *page, |
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struct iomap *iomap) |
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{ |
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size_t size = i_size_read(inode); |
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void *addr; |
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|
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if (PageUptodate(page)) |
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return; |
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|
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BUG_ON(page->index); |
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BUG_ON(size > PAGE_SIZE - offset_in_page(iomap->inline_data)); |
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|
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addr = kmap_atomic(page); |
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memcpy(addr, iomap->inline_data, size); |
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memset(addr + size, 0, PAGE_SIZE - size); |
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kunmap_atomic(addr); |
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SetPageUptodate(page); |
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} |
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|
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static inline bool iomap_block_needs_zeroing(struct inode *inode, |
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struct iomap *iomap, loff_t pos) |
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{ |
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return iomap->type != IOMAP_MAPPED || |
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(iomap->flags & IOMAP_F_NEW) || |
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pos >= i_size_read(inode); |
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} |
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|
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static loff_t |
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iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data, |
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struct iomap *iomap, struct iomap *srcmap) |
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{ |
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struct iomap_readpage_ctx *ctx = data; |
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struct page *page = ctx->cur_page; |
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struct iomap_page *iop = iomap_page_create(inode, page); |
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bool same_page = false, is_contig = false; |
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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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|
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if (iomap->type == IOMAP_INLINE) { |
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WARN_ON_ONCE(pos); |
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iomap_read_inline_data(inode, page, iomap); |
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return PAGE_SIZE; |
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} |
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|
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/* zero post-eof blocks as the page may be mapped */ |
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iomap_adjust_read_range(inode, iop, &pos, length, &poff, &plen); |
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if (plen == 0) |
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goto done; |
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|
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if (iomap_block_needs_zeroing(inode, iomap, 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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|
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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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|
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/* Try to merge into a previous segment if we can */ |
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sector = iomap_sector(iomap, pos); |
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if (ctx->bio && bio_end_sector(ctx->bio) == sector) { |
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if (__bio_try_merge_page(ctx->bio, page, plen, poff, |
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&same_page)) |
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goto done; |
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is_contig = true; |
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} |
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|
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if (!is_contig || bio_full(ctx->bio, 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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|
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if (ctx->bio) |
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submit_bio(ctx->bio); |
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|
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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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} |
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|
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bio_add_page(ctx->bio, page, plen, poff); |
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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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|
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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_readpage_ctx ctx = { .cur_page = page }; |
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struct inode *inode = page->mapping->host; |
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unsigned poff; |
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loff_t ret; |
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|
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trace_iomap_readpage(page->mapping->host, 1); |
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|
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for (poff = 0; poff < PAGE_SIZE; poff += ret) { |
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ret = iomap_apply(inode, page_offset(page) + poff, |
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PAGE_SIZE - poff, 0, ops, &ctx, |
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iomap_readpage_actor); |
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if (ret <= 0) { |
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WARN_ON_ONCE(ret == 0); |
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SetPageError(page); |
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break; |
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} |
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} |
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|
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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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/* |
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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 all through 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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|
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static loff_t |
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iomap_readahead_actor(struct inode *inode, loff_t pos, loff_t length, |
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void *data, struct iomap *iomap, struct iomap *srcmap) |
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{ |
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struct iomap_readpage_ctx *ctx = data; |
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loff_t done, ret; |
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|
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for (done = 0; done < length; done += ret) { |
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if (ctx->cur_page && offset_in_page(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_actor(inode, pos + done, length - done, |
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ctx, iomap, srcmap); |
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} |
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|
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return done; |
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} |
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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 inode *inode = rac->mapping->host; |
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loff_t pos = readahead_pos(rac); |
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loff_t length = readahead_length(rac); |
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struct iomap_readpage_ctx ctx = { |
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.rac = rac, |
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}; |
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|
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trace_iomap_readahead(inode, readahead_count(rac)); |
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|
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while (length > 0) { |
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loff_t ret = iomap_apply(inode, pos, length, 0, ops, |
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&ctx, iomap_readahead_actor); |
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if (ret <= 0) { |
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WARN_ON_ONCE(ret == 0); |
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break; |
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} |
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pos += ret; |
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length -= ret; |
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} |
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|
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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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/* |
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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 are invalidating the entire page, clear the dirty state from it |
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* and release it to avoid unnecessary buildup of the LRU. |
|
*/ |
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if (offset == 0 && len == PAGE_SIZE) { |
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WARN_ON_ONCE(PageWriteback(page)); |
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cancel_dirty_page(page); |
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iomap_page_release(page); |
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} |
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} |
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EXPORT_SYMBOL_GPL(iomap_invalidatepage); |
|
|
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#ifdef CONFIG_MIGRATION |
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int |
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iomap_migrate_page(struct address_space *mapping, struct page *newpage, |
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struct page *page, enum migrate_mode mode) |
|
{ |
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int ret; |
|
|
|
ret = migrate_page_move_mapping(mapping, newpage, page, 0); |
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if (ret != MIGRATEPAGE_SUCCESS) |
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return ret; |
|
|
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if (page_has_private(page)) |
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attach_page_private(newpage, detach_page_private(page)); |
|
|
|
if (mode != MIGRATE_SYNC_NO_COPY) |
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migrate_page_copy(newpage, page); |
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else |
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migrate_page_states(newpage, page); |
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return MIGRATEPAGE_SUCCESS; |
|
} |
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EXPORT_SYMBOL_GPL(iomap_migrate_page); |
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#endif /* CONFIG_MIGRATION */ |
|
|
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enum { |
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IOMAP_WRITE_F_UNSHARE = (1 << 0), |
|
}; |
|
|
|
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) |
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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, struct iomap *iomap) |
|
{ |
|
struct bio_vec bvec; |
|
struct bio bio; |
|
|
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bio_init(&bio, &bvec, 1); |
|
bio.bi_opf = REQ_OP_READ; |
|
bio.bi_iter.bi_sector = iomap_sector(iomap, block_start); |
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bio_set_dev(&bio, iomap->bdev); |
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__bio_add_page(&bio, page, plen, poff); |
|
return submit_bio_wait(&bio); |
|
} |
|
|
|
static int |
|
__iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags, |
|
struct page *page, struct iomap *srcmap) |
|
{ |
|
struct iomap_page *iop = iomap_page_create(inode, page); |
|
loff_t block_size = i_blocksize(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(inode, iop, &block_start, |
|
block_end - block_start, &poff, &plen); |
|
if (plen == 0) |
|
break; |
|
|
|
if (!(flags & IOMAP_WRITE_F_UNSHARE) && |
|
(from <= poff || from >= poff + plen) && |
|
(to <= poff || to >= poff + plen)) |
|
continue; |
|
|
|
if (iomap_block_needs_zeroing(inode, srcmap, block_start)) { |
|
if (WARN_ON_ONCE(flags & IOMAP_WRITE_F_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(struct inode *inode, loff_t pos, unsigned len, unsigned flags, |
|
struct page **pagep, struct iomap *iomap, struct iomap *srcmap) |
|
{ |
|
const struct iomap_page_ops *page_ops = iomap->page_ops; |
|
struct page *page; |
|
int status = 0; |
|
|
|
BUG_ON(pos + len > iomap->offset + iomap->length); |
|
if (srcmap != 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(inode, pos, len, iomap); |
|
if (status) |
|
return status; |
|
} |
|
|
|
page = grab_cache_page_write_begin(inode->i_mapping, pos >> PAGE_SHIFT, |
|
AOP_FLAG_NOFS); |
|
if (!page) { |
|
status = -ENOMEM; |
|
goto out_no_page; |
|
} |
|
|
|
if (srcmap->type == IOMAP_INLINE) |
|
iomap_read_inline_data(inode, page, srcmap); |
|
else if (iomap->flags & IOMAP_F_BUFFER_HEAD) |
|
status = __block_write_begin_int(page, pos, len, NULL, srcmap); |
|
else |
|
status = __iomap_write_begin(inode, pos, len, flags, page, |
|
srcmap); |
|
|
|
if (unlikely(status)) |
|
goto out_unlock; |
|
|
|
*pagep = page; |
|
return 0; |
|
|
|
out_unlock: |
|
unlock_page(page); |
|
put_page(page); |
|
iomap_write_failed(inode, pos, len); |
|
|
|
out_no_page: |
|
if (page_ops && page_ops->page_done) |
|
page_ops->page_done(inode, pos, 0, NULL, iomap); |
|
return status; |
|
} |
|
|
|
int |
|
iomap_set_page_dirty(struct page *page) |
|
{ |
|
struct address_space *mapping = page_mapping(page); |
|
int newly_dirty; |
|
|
|
if (unlikely(!mapping)) |
|
return !TestSetPageDirty(page); |
|
|
|
/* |
|
* Lock out page's memcg migration to keep PageDirty |
|
* synchronized with per-memcg dirty page counters. |
|
*/ |
|
lock_page_memcg(page); |
|
newly_dirty = !TestSetPageDirty(page); |
|
if (newly_dirty) |
|
__set_page_dirty(page, mapping, 0); |
|
unlock_page_memcg(page); |
|
|
|
if (newly_dirty) |
|
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES); |
|
return newly_dirty; |
|
} |
|
EXPORT_SYMBOL_GPL(iomap_set_page_dirty); |
|
|
|
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 have 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); |
|
iomap_set_page_dirty(page); |
|
return copied; |
|
} |
|
|
|
static size_t iomap_write_end_inline(struct inode *inode, struct page *page, |
|
struct iomap *iomap, loff_t pos, size_t copied) |
|
{ |
|
void *addr; |
|
|
|
WARN_ON_ONCE(!PageUptodate(page)); |
|
BUG_ON(pos + copied > PAGE_SIZE - offset_in_page(iomap->inline_data)); |
|
|
|
flush_dcache_page(page); |
|
addr = kmap_atomic(page); |
|
memcpy(iomap->inline_data + pos, addr + pos, copied); |
|
kunmap_atomic(addr); |
|
|
|
mark_inode_dirty(inode); |
|
return copied; |
|
} |
|
|
|
/* Returns the number of bytes copied. May be 0. Cannot be an errno. */ |
|
static size_t iomap_write_end(struct inode *inode, loff_t pos, size_t len, |
|
size_t copied, struct page *page, struct iomap *iomap, |
|
struct iomap *srcmap) |
|
{ |
|
const struct iomap_page_ops *page_ops = iomap->page_ops; |
|
loff_t old_size = inode->i_size; |
|
size_t ret; |
|
|
|
if (srcmap->type == IOMAP_INLINE) { |
|
ret = iomap_write_end_inline(inode, page, iomap, pos, copied); |
|
} else if (srcmap->flags & IOMAP_F_BUFFER_HEAD) { |
|
ret = block_write_end(NULL, inode->i_mapping, pos, len, copied, |
|
page, NULL); |
|
} else { |
|
ret = __iomap_write_end(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(inode, pos + ret); |
|
iomap->flags |= IOMAP_F_SIZE_CHANGED; |
|
} |
|
unlock_page(page); |
|
|
|
if (old_size < pos) |
|
pagecache_isize_extended(inode, old_size, pos); |
|
if (page_ops && page_ops->page_done) |
|
page_ops->page_done(inode, pos, ret, page, iomap); |
|
put_page(page); |
|
|
|
if (ret < len) |
|
iomap_write_failed(inode, pos, len); |
|
return ret; |
|
} |
|
|
|
static loff_t |
|
iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, |
|
struct iomap *iomap, struct iomap *srcmap) |
|
{ |
|
struct iov_iter *i = data; |
|
long status = 0; |
|
ssize_t written = 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 will 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. |
|
* |
|
* Not only is this an optimisation, but it is also required |
|
* to check that the address is actually valid, when atomic |
|
* usercopies are used, below. |
|
*/ |
|
if (unlikely(iov_iter_fault_in_readable(i, bytes))) { |
|
status = -EFAULT; |
|
break; |
|
} |
|
|
|
status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap, |
|
srcmap); |
|
if (unlikely(status)) |
|
break; |
|
|
|
if (mapping_writably_mapped(inode->i_mapping)) |
|
flush_dcache_page(page); |
|
|
|
copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes); |
|
|
|
copied = iomap_write_end(inode, pos, bytes, copied, page, iomap, |
|
srcmap); |
|
|
|
cond_resched(); |
|
|
|
iov_iter_advance(i, copied); |
|
if (unlikely(copied == 0)) { |
|
/* |
|
* If we were unable to copy any data at all, we must |
|
* fall back to a single segment length write. |
|
* |
|
* If we didn't fallback here, we could livelock |
|
* because not all segments in the iov can be copied at |
|
* once without a pagefault. |
|
*/ |
|
bytes = min_t(unsigned long, PAGE_SIZE - offset, |
|
iov_iter_single_seg_count(i)); |
|
goto again; |
|
} |
|
pos += copied; |
|
written += copied; |
|
length -= copied; |
|
|
|
balance_dirty_pages_ratelimited(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 *iter, |
|
const struct iomap_ops *ops) |
|
{ |
|
struct inode *inode = iocb->ki_filp->f_mapping->host; |
|
loff_t pos = iocb->ki_pos, ret = 0, written = 0; |
|
|
|
while (iov_iter_count(iter)) { |
|
ret = iomap_apply(inode, pos, iov_iter_count(iter), |
|
IOMAP_WRITE, ops, iter, iomap_write_actor); |
|
if (ret <= 0) |
|
break; |
|
pos += ret; |
|
written += ret; |
|
} |
|
|
|
return written ? written : ret; |
|
} |
|
EXPORT_SYMBOL_GPL(iomap_file_buffered_write); |
|
|
|
static loff_t |
|
iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, |
|
struct iomap *iomap, struct iomap *srcmap) |
|
{ |
|
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(inode, pos, bytes, |
|
IOMAP_WRITE_F_UNSHARE, &page, iomap, srcmap); |
|
if (unlikely(status)) |
|
return status; |
|
|
|
status = iomap_write_end(inode, pos, bytes, bytes, page, iomap, |
|
srcmap); |
|
if (WARN_ON_ONCE(status == 0)) |
|
return -EIO; |
|
|
|
cond_resched(); |
|
|
|
pos += status; |
|
written += status; |
|
length -= status; |
|
|
|
balance_dirty_pages_ratelimited(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) |
|
{ |
|
loff_t ret; |
|
|
|
while (len) { |
|
ret = iomap_apply(inode, pos, len, IOMAP_WRITE, ops, NULL, |
|
iomap_unshare_actor); |
|
if (ret <= 0) |
|
return ret; |
|
pos += ret; |
|
len -= ret; |
|
} |
|
|
|
return 0; |
|
} |
|
EXPORT_SYMBOL_GPL(iomap_file_unshare); |
|
|
|
static s64 iomap_zero(struct inode *inode, loff_t pos, u64 length, |
|
struct iomap *iomap, struct iomap *srcmap) |
|
{ |
|
struct page *page; |
|
int status; |
|
unsigned offset = offset_in_page(pos); |
|
unsigned bytes = min_t(u64, PAGE_SIZE - offset, length); |
|
|
|
status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap, srcmap); |
|
if (status) |
|
return status; |
|
|
|
zero_user(page, offset, bytes); |
|
mark_page_accessed(page); |
|
|
|
return iomap_write_end(inode, pos, bytes, bytes, page, iomap, srcmap); |
|
} |
|
|
|
static loff_t iomap_zero_range_actor(struct inode *inode, loff_t pos, |
|
loff_t length, void *data, struct iomap *iomap, |
|
struct iomap *srcmap) |
|
{ |
|
bool *did_zero = data; |
|
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(inode)) |
|
bytes = dax_iomap_zero(pos, length, iomap); |
|
else |
|
bytes = iomap_zero(inode, pos, length, iomap, srcmap); |
|
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) |
|
{ |
|
loff_t ret; |
|
|
|
while (len > 0) { |
|
ret = iomap_apply(inode, pos, len, IOMAP_ZERO, |
|
ops, did_zero, iomap_zero_range_actor); |
|
if (ret <= 0) |
|
return ret; |
|
|
|
pos += ret; |
|
len -= ret; |
|
} |
|
|
|
return 0; |
|
} |
|
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_actor(struct inode *inode, loff_t pos, loff_t length, |
|
void *data, struct iomap *iomap, struct iomap *srcmap) |
|
{ |
|
struct page *page = data; |
|
int ret; |
|
|
|
if (iomap->flags & IOMAP_F_BUFFER_HEAD) { |
|
ret = __block_write_begin_int(page, pos, length, NULL, iomap); |
|
if (ret) |
|
return ret; |
|
block_commit_write(page, 0, length); |
|
} else { |
|
WARN_ON_ONCE(!PageUptodate(page)); |
|
iomap_page_create(inode, page); |
|
set_page_dirty(page); |
|
} |
|
|
|
return length; |
|
} |
|
|
|
vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops) |
|
{ |
|
struct page *page = vmf->page; |
|
struct inode *inode = file_inode(vmf->vma->vm_file); |
|
unsigned long length; |
|
loff_t offset; |
|
ssize_t ret; |
|
|
|
lock_page(page); |
|
ret = page_mkwrite_check_truncate(page, inode); |
|
if (ret < 0) |
|
goto out_unlock; |
|
length = ret; |
|
|
|
offset = page_offset(page); |
|
while (length > 0) { |
|
ret = iomap_apply(inode, offset, length, |
|
IOMAP_WRITE | IOMAP_FAULT, ops, page, |
|
iomap_page_mkwrite_actor); |
|
if (unlikely(ret <= 0)) |
|
goto out_unlock; |
|
offset += ret; |
|
length -= ret; |
|
} |
|
|
|
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, -EIO); |
|
} |
|
|
|
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, |
|
void (*merge_private)(struct iomap_ioend *ioend, |
|
struct iomap_ioend *next)) |
|
{ |
|
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; |
|
if (next->io_private && merge_private) |
|
merge_private(ioend, next); |
|
} |
|
} |
|
EXPORT_SYMBOL_GPL(iomap_ioend_try_merge); |
|
|
|
static int |
|
iomap_ioend_compare(void *priv, struct list_head *a, 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 have marked paged 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 are 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_private = NULL; |
|
ioend->io_bio = bio; |
|
return ioend; |
|
} |
|
|
|
/* |
|
* Allocate a new bio, and chain the old bio to the new one. |
|
* |
|
* Note that we have to do 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); |
|
bool merged, same_page = false; |
|
|
|
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); |
|
} |
|
|
|
merged = __bio_try_merge_page(wpc->ioend->io_bio, page, len, poff, |
|
&same_page); |
|
if (iop) |
|
atomic_add(len, &iop->write_bytes_pending); |
|
|
|
if (!merged) { |
|
if (bio_full(wpc->ioend->io_bio, len)) { |
|
wpc->ioend->io_bio = |
|
iomap_chain_bio(wpc->ioend->io_bio); |
|
} |
|
bio_add_page(wpc->ioend->io_bio, page, len, poff); |
|
} |
|
|
|
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 |
|
* forward progress guarantees we need to provide. The current ioend we are |
|
* adding blocks to is cached on the writepage context, and if the new block |
|
* does not 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 = to_iomap_page(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(i_blocks_per_page(inode, page) > 1 && !iop); |
|
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 wasn'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, otherwise 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 are 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 is fully outside i_size, e.g. due to a |
|
* truncate operation that is 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, it would overflow |
|
* if the given offset is greater than 16TB on 32-bit system |
|
* and if we do check the page is fully outside i_size or not |
|
* via "if (page->index >= end_index + 1)" as "end_index + 1" |
|
* will be evaluated to 0. Hence this page will be redirtied |
|
* and be written out repeatedly which would result in an |
|
* infinite loop, the user program that perform this operation |
|
* will hang. Instead, we can verify this situation by checking |
|
* if the page to write is totally beyond the i_size or if it's |
|
* 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);
|
|
|