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f611ff6375
This is close to a 1:1 replacement of radix tree APIs with their XArray equivalents. It would be possible to optimise nilfs_copy_back_pages(), but that doesn't seem to be in the performance path. Also, I think it has a pre-existing bug, and I've added a note to that effect in the source code. Signed-off-by: Matthew Wilcox <willy@infradead.org>
562 lines
14 KiB
C
562 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* page.c - buffer/page management specific to NILFS
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*
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* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
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*
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* Written by Ryusuke Konishi and Seiji Kihara.
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*/
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#include <linux/pagemap.h>
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#include <linux/writeback.h>
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#include <linux/swap.h>
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#include <linux/bitops.h>
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#include <linux/page-flags.h>
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#include <linux/list.h>
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#include <linux/highmem.h>
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#include <linux/pagevec.h>
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#include <linux/gfp.h>
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#include "nilfs.h"
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#include "page.h"
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#include "mdt.h"
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#define NILFS_BUFFER_INHERENT_BITS \
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(BIT(BH_Uptodate) | BIT(BH_Mapped) | BIT(BH_NILFS_Node) | \
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BIT(BH_NILFS_Volatile) | BIT(BH_NILFS_Checked))
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static struct buffer_head *
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__nilfs_get_page_block(struct page *page, unsigned long block, pgoff_t index,
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int blkbits, unsigned long b_state)
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{
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unsigned long first_block;
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struct buffer_head *bh;
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if (!page_has_buffers(page))
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create_empty_buffers(page, 1 << blkbits, b_state);
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first_block = (unsigned long)index << (PAGE_SHIFT - blkbits);
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bh = nilfs_page_get_nth_block(page, block - first_block);
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touch_buffer(bh);
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wait_on_buffer(bh);
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return bh;
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}
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struct buffer_head *nilfs_grab_buffer(struct inode *inode,
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struct address_space *mapping,
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unsigned long blkoff,
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unsigned long b_state)
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{
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int blkbits = inode->i_blkbits;
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pgoff_t index = blkoff >> (PAGE_SHIFT - blkbits);
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struct page *page;
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struct buffer_head *bh;
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page = grab_cache_page(mapping, index);
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if (unlikely(!page))
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return NULL;
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bh = __nilfs_get_page_block(page, blkoff, index, blkbits, b_state);
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if (unlikely(!bh)) {
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unlock_page(page);
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put_page(page);
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return NULL;
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}
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return bh;
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}
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/**
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* nilfs_forget_buffer - discard dirty state
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* @inode: owner inode of the buffer
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* @bh: buffer head of the buffer to be discarded
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*/
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void nilfs_forget_buffer(struct buffer_head *bh)
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{
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struct page *page = bh->b_page;
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const unsigned long clear_bits =
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(BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
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BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
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BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected));
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lock_buffer(bh);
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set_mask_bits(&bh->b_state, clear_bits, 0);
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if (nilfs_page_buffers_clean(page))
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__nilfs_clear_page_dirty(page);
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bh->b_blocknr = -1;
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ClearPageUptodate(page);
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ClearPageMappedToDisk(page);
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unlock_buffer(bh);
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brelse(bh);
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}
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/**
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* nilfs_copy_buffer -- copy buffer data and flags
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* @dbh: destination buffer
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* @sbh: source buffer
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*/
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void nilfs_copy_buffer(struct buffer_head *dbh, struct buffer_head *sbh)
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{
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void *kaddr0, *kaddr1;
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unsigned long bits;
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struct page *spage = sbh->b_page, *dpage = dbh->b_page;
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struct buffer_head *bh;
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kaddr0 = kmap_atomic(spage);
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kaddr1 = kmap_atomic(dpage);
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memcpy(kaddr1 + bh_offset(dbh), kaddr0 + bh_offset(sbh), sbh->b_size);
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kunmap_atomic(kaddr1);
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kunmap_atomic(kaddr0);
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dbh->b_state = sbh->b_state & NILFS_BUFFER_INHERENT_BITS;
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dbh->b_blocknr = sbh->b_blocknr;
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dbh->b_bdev = sbh->b_bdev;
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bh = dbh;
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bits = sbh->b_state & (BIT(BH_Uptodate) | BIT(BH_Mapped));
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while ((bh = bh->b_this_page) != dbh) {
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lock_buffer(bh);
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bits &= bh->b_state;
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unlock_buffer(bh);
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}
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if (bits & BIT(BH_Uptodate))
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SetPageUptodate(dpage);
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else
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ClearPageUptodate(dpage);
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if (bits & BIT(BH_Mapped))
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SetPageMappedToDisk(dpage);
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else
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ClearPageMappedToDisk(dpage);
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}
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/**
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* nilfs_page_buffers_clean - check if a page has dirty buffers or not.
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* @page: page to be checked
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*
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* nilfs_page_buffers_clean() returns zero if the page has dirty buffers.
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* Otherwise, it returns non-zero value.
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*/
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int nilfs_page_buffers_clean(struct page *page)
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{
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struct buffer_head *bh, *head;
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bh = head = page_buffers(page);
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do {
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if (buffer_dirty(bh))
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return 0;
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bh = bh->b_this_page;
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} while (bh != head);
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return 1;
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}
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void nilfs_page_bug(struct page *page)
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{
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struct address_space *m;
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unsigned long ino;
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if (unlikely(!page)) {
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printk(KERN_CRIT "NILFS_PAGE_BUG(NULL)\n");
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return;
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}
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m = page->mapping;
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ino = m ? m->host->i_ino : 0;
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printk(KERN_CRIT "NILFS_PAGE_BUG(%p): cnt=%d index#=%llu flags=0x%lx "
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"mapping=%p ino=%lu\n",
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page, page_ref_count(page),
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(unsigned long long)page->index, page->flags, m, ino);
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if (page_has_buffers(page)) {
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struct buffer_head *bh, *head;
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int i = 0;
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bh = head = page_buffers(page);
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do {
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printk(KERN_CRIT
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" BH[%d] %p: cnt=%d block#=%llu state=0x%lx\n",
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i++, bh, atomic_read(&bh->b_count),
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(unsigned long long)bh->b_blocknr, bh->b_state);
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bh = bh->b_this_page;
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} while (bh != head);
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}
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}
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/**
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* nilfs_copy_page -- copy the page with buffers
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* @dst: destination page
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* @src: source page
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* @copy_dirty: flag whether to copy dirty states on the page's buffer heads.
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*
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* This function is for both data pages and btnode pages. The dirty flag
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* should be treated by caller. The page must not be under i/o.
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* Both src and dst page must be locked
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*/
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static void nilfs_copy_page(struct page *dst, struct page *src, int copy_dirty)
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{
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struct buffer_head *dbh, *dbufs, *sbh, *sbufs;
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unsigned long mask = NILFS_BUFFER_INHERENT_BITS;
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BUG_ON(PageWriteback(dst));
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sbh = sbufs = page_buffers(src);
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if (!page_has_buffers(dst))
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create_empty_buffers(dst, sbh->b_size, 0);
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if (copy_dirty)
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mask |= BIT(BH_Dirty);
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dbh = dbufs = page_buffers(dst);
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do {
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lock_buffer(sbh);
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lock_buffer(dbh);
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dbh->b_state = sbh->b_state & mask;
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dbh->b_blocknr = sbh->b_blocknr;
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dbh->b_bdev = sbh->b_bdev;
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sbh = sbh->b_this_page;
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dbh = dbh->b_this_page;
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} while (dbh != dbufs);
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copy_highpage(dst, src);
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if (PageUptodate(src) && !PageUptodate(dst))
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SetPageUptodate(dst);
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else if (!PageUptodate(src) && PageUptodate(dst))
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ClearPageUptodate(dst);
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if (PageMappedToDisk(src) && !PageMappedToDisk(dst))
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SetPageMappedToDisk(dst);
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else if (!PageMappedToDisk(src) && PageMappedToDisk(dst))
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ClearPageMappedToDisk(dst);
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do {
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unlock_buffer(sbh);
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unlock_buffer(dbh);
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sbh = sbh->b_this_page;
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dbh = dbh->b_this_page;
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} while (dbh != dbufs);
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}
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int nilfs_copy_dirty_pages(struct address_space *dmap,
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struct address_space *smap)
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{
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struct pagevec pvec;
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unsigned int i;
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pgoff_t index = 0;
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int err = 0;
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pagevec_init(&pvec);
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repeat:
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if (!pagevec_lookup_tag(&pvec, smap, &index, PAGECACHE_TAG_DIRTY))
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return 0;
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for (i = 0; i < pagevec_count(&pvec); i++) {
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struct page *page = pvec.pages[i], *dpage;
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lock_page(page);
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if (unlikely(!PageDirty(page)))
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NILFS_PAGE_BUG(page, "inconsistent dirty state");
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dpage = grab_cache_page(dmap, page->index);
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if (unlikely(!dpage)) {
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/* No empty page is added to the page cache */
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err = -ENOMEM;
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unlock_page(page);
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break;
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}
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if (unlikely(!page_has_buffers(page)))
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NILFS_PAGE_BUG(page,
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"found empty page in dat page cache");
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nilfs_copy_page(dpage, page, 1);
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__set_page_dirty_nobuffers(dpage);
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unlock_page(dpage);
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put_page(dpage);
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unlock_page(page);
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}
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pagevec_release(&pvec);
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cond_resched();
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if (likely(!err))
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goto repeat;
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return err;
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}
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/**
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* nilfs_copy_back_pages -- copy back pages to original cache from shadow cache
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* @dmap: destination page cache
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* @smap: source page cache
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*
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* No pages must be added to the cache during this process.
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* This must be ensured by the caller.
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*/
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void nilfs_copy_back_pages(struct address_space *dmap,
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struct address_space *smap)
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{
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struct pagevec pvec;
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unsigned int i, n;
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pgoff_t index = 0;
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pagevec_init(&pvec);
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repeat:
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n = pagevec_lookup(&pvec, smap, &index);
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if (!n)
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return;
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for (i = 0; i < pagevec_count(&pvec); i++) {
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struct page *page = pvec.pages[i], *dpage;
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pgoff_t offset = page->index;
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lock_page(page);
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dpage = find_lock_page(dmap, offset);
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if (dpage) {
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/* overwrite existing page in the destination cache */
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WARN_ON(PageDirty(dpage));
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nilfs_copy_page(dpage, page, 0);
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unlock_page(dpage);
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put_page(dpage);
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/* Do we not need to remove page from smap here? */
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} else {
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struct page *p;
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/* move the page to the destination cache */
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xa_lock_irq(&smap->i_pages);
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p = __xa_erase(&smap->i_pages, offset);
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WARN_ON(page != p);
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smap->nrpages--;
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xa_unlock_irq(&smap->i_pages);
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xa_lock_irq(&dmap->i_pages);
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p = __xa_store(&dmap->i_pages, offset, page, GFP_NOFS);
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if (unlikely(p)) {
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/* Probably -ENOMEM */
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page->mapping = NULL;
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put_page(page);
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} else {
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page->mapping = dmap;
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dmap->nrpages++;
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if (PageDirty(page))
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__xa_set_mark(&dmap->i_pages, offset,
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PAGECACHE_TAG_DIRTY);
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}
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xa_unlock_irq(&dmap->i_pages);
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}
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unlock_page(page);
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}
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pagevec_release(&pvec);
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cond_resched();
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goto repeat;
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}
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/**
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* nilfs_clear_dirty_pages - discard dirty pages in address space
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* @mapping: address space with dirty pages for discarding
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* @silent: suppress [true] or print [false] warning messages
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*/
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void nilfs_clear_dirty_pages(struct address_space *mapping, bool silent)
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{
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struct pagevec pvec;
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unsigned int i;
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pgoff_t index = 0;
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pagevec_init(&pvec);
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while (pagevec_lookup_tag(&pvec, mapping, &index,
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PAGECACHE_TAG_DIRTY)) {
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for (i = 0; i < pagevec_count(&pvec); i++) {
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struct page *page = pvec.pages[i];
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lock_page(page);
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nilfs_clear_dirty_page(page, silent);
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unlock_page(page);
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}
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pagevec_release(&pvec);
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cond_resched();
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}
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}
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/**
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* nilfs_clear_dirty_page - discard dirty page
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* @page: dirty page that will be discarded
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* @silent: suppress [true] or print [false] warning messages
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*/
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void nilfs_clear_dirty_page(struct page *page, bool silent)
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{
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struct inode *inode = page->mapping->host;
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struct super_block *sb = inode->i_sb;
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BUG_ON(!PageLocked(page));
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if (!silent)
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nilfs_msg(sb, KERN_WARNING,
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"discard dirty page: offset=%lld, ino=%lu",
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page_offset(page), inode->i_ino);
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ClearPageUptodate(page);
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ClearPageMappedToDisk(page);
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if (page_has_buffers(page)) {
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struct buffer_head *bh, *head;
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const unsigned long clear_bits =
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(BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
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BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
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BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected));
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bh = head = page_buffers(page);
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do {
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lock_buffer(bh);
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if (!silent)
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nilfs_msg(sb, KERN_WARNING,
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"discard dirty block: blocknr=%llu, size=%zu",
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(u64)bh->b_blocknr, bh->b_size);
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set_mask_bits(&bh->b_state, clear_bits, 0);
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unlock_buffer(bh);
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} while (bh = bh->b_this_page, bh != head);
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}
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__nilfs_clear_page_dirty(page);
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}
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unsigned int nilfs_page_count_clean_buffers(struct page *page,
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unsigned int from, unsigned int to)
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{
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unsigned int block_start, block_end;
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struct buffer_head *bh, *head;
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unsigned int nc = 0;
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for (bh = head = page_buffers(page), block_start = 0;
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bh != head || !block_start;
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block_start = block_end, bh = bh->b_this_page) {
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block_end = block_start + bh->b_size;
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if (block_end > from && block_start < to && !buffer_dirty(bh))
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nc++;
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}
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return nc;
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}
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void nilfs_mapping_init(struct address_space *mapping, struct inode *inode)
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{
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mapping->host = inode;
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mapping->flags = 0;
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mapping_set_gfp_mask(mapping, GFP_NOFS);
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mapping->private_data = NULL;
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mapping->a_ops = &empty_aops;
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}
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/*
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* NILFS2 needs clear_page_dirty() in the following two cases:
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*
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* 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears
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* page dirty flags when it copies back pages from the shadow cache
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* (gcdat->{i_mapping,i_btnode_cache}) to its original cache
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* (dat->{i_mapping,i_btnode_cache}).
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*
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* 2) Some B-tree operations like insertion or deletion may dispose buffers
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* in dirty state, and this needs to cancel the dirty state of their pages.
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*/
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int __nilfs_clear_page_dirty(struct page *page)
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{
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struct address_space *mapping = page->mapping;
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if (mapping) {
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xa_lock_irq(&mapping->i_pages);
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if (test_bit(PG_dirty, &page->flags)) {
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__xa_clear_mark(&mapping->i_pages, page_index(page),
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PAGECACHE_TAG_DIRTY);
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xa_unlock_irq(&mapping->i_pages);
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return clear_page_dirty_for_io(page);
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}
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xa_unlock_irq(&mapping->i_pages);
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return 0;
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}
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return TestClearPageDirty(page);
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}
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/**
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* nilfs_find_uncommitted_extent - find extent of uncommitted data
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* @inode: inode
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* @start_blk: start block offset (in)
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* @blkoff: start offset of the found extent (out)
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*
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* This function searches an extent of buffers marked "delayed" which
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* starts from a block offset equal to or larger than @start_blk. If
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* such an extent was found, this will store the start offset in
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* @blkoff and return its length in blocks. Otherwise, zero is
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* returned.
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*/
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unsigned long nilfs_find_uncommitted_extent(struct inode *inode,
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sector_t start_blk,
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sector_t *blkoff)
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{
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unsigned int i;
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pgoff_t index;
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unsigned int nblocks_in_page;
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unsigned long length = 0;
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sector_t b;
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struct pagevec pvec;
|
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struct page *page;
|
|
|
|
if (inode->i_mapping->nrpages == 0)
|
|
return 0;
|
|
|
|
index = start_blk >> (PAGE_SHIFT - inode->i_blkbits);
|
|
nblocks_in_page = 1U << (PAGE_SHIFT - inode->i_blkbits);
|
|
|
|
pagevec_init(&pvec);
|
|
|
|
repeat:
|
|
pvec.nr = find_get_pages_contig(inode->i_mapping, index, PAGEVEC_SIZE,
|
|
pvec.pages);
|
|
if (pvec.nr == 0)
|
|
return length;
|
|
|
|
if (length > 0 && pvec.pages[0]->index > index)
|
|
goto out;
|
|
|
|
b = pvec.pages[0]->index << (PAGE_SHIFT - inode->i_blkbits);
|
|
i = 0;
|
|
do {
|
|
page = pvec.pages[i];
|
|
|
|
lock_page(page);
|
|
if (page_has_buffers(page)) {
|
|
struct buffer_head *bh, *head;
|
|
|
|
bh = head = page_buffers(page);
|
|
do {
|
|
if (b < start_blk)
|
|
continue;
|
|
if (buffer_delay(bh)) {
|
|
if (length == 0)
|
|
*blkoff = b;
|
|
length++;
|
|
} else if (length > 0) {
|
|
goto out_locked;
|
|
}
|
|
} while (++b, bh = bh->b_this_page, bh != head);
|
|
} else {
|
|
if (length > 0)
|
|
goto out_locked;
|
|
|
|
b += nblocks_in_page;
|
|
}
|
|
unlock_page(page);
|
|
|
|
} while (++i < pagevec_count(&pvec));
|
|
|
|
index = page->index + 1;
|
|
pagevec_release(&pvec);
|
|
cond_resched();
|
|
goto repeat;
|
|
|
|
out_locked:
|
|
unlock_page(page);
|
|
out:
|
|
pagevec_release(&pvec);
|
|
return length;
|
|
}
|