542 lines
13 KiB
C
542 lines
13 KiB
C
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// SPDX-License-Identifier: GPL-2.0+
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/*
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* 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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* @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;
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unsigned long mask = NILFS_BUFFER_INHERENT_BITS;
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BUG_ON(PageWriteback(dst));
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sbh = 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 folio_batch fbatch;
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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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folio_batch_init(&fbatch);
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repeat:
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if (!filemap_get_folios_tag(smap, &index, (pgoff_t)-1,
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PAGECACHE_TAG_DIRTY, &fbatch))
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return 0;
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for (i = 0; i < folio_batch_count(&fbatch); i++) {
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struct folio *folio = fbatch.folios[i], *dfolio;
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folio_lock(folio);
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if (unlikely(!folio_test_dirty(folio)))
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NILFS_PAGE_BUG(&folio->page, "inconsistent dirty state");
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dfolio = filemap_grab_folio(dmap, folio->index);
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if (unlikely(!dfolio)) {
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/* No empty page is added to the page cache */
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err = -ENOMEM;
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folio_unlock(folio);
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break;
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}
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if (unlikely(!folio_buffers(folio)))
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NILFS_PAGE_BUG(&folio->page,
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"found empty page in dat page cache");
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nilfs_copy_page(&dfolio->page, &folio->page, 1);
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filemap_dirty_folio(folio_mapping(dfolio), dfolio);
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folio_unlock(dfolio);
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folio_put(dfolio);
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folio_unlock(folio);
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}
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folio_batch_release(&fbatch);
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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 folio_batch fbatch;
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unsigned int i, n;
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pgoff_t start = 0;
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folio_batch_init(&fbatch);
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repeat:
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n = filemap_get_folios(smap, &start, ~0UL, &fbatch);
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if (!n)
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return;
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for (i = 0; i < folio_batch_count(&fbatch); i++) {
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struct folio *folio = fbatch.folios[i], *dfolio;
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pgoff_t index = folio->index;
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folio_lock(folio);
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dfolio = filemap_lock_folio(dmap, index);
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if (dfolio) {
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/* overwrite existing folio in the destination cache */
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WARN_ON(folio_test_dirty(dfolio));
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nilfs_copy_page(&dfolio->page, &folio->page, 0);
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folio_unlock(dfolio);
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folio_put(dfolio);
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/* Do we not need to remove folio from smap here? */
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} else {
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struct folio *f;
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/* move the folio to the destination cache */
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xa_lock_irq(&smap->i_pages);
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f = __xa_erase(&smap->i_pages, index);
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WARN_ON(folio != f);
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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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f = __xa_store(&dmap->i_pages, index, folio, GFP_NOFS);
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if (unlikely(f)) {
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/* Probably -ENOMEM */
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folio->mapping = NULL;
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folio_put(folio);
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} else {
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folio->mapping = dmap;
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dmap->nrpages++;
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if (folio_test_dirty(folio))
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__xa_set_mark(&dmap->i_pages, index,
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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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folio_unlock(folio);
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}
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folio_batch_release(&fbatch);
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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 folio_batch fbatch;
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unsigned int i;
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pgoff_t index = 0;
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folio_batch_init(&fbatch);
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while (filemap_get_folios_tag(mapping, &index, (pgoff_t)-1,
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PAGECACHE_TAG_DIRTY, &fbatch)) {
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|
|
for (i = 0; i < folio_batch_count(&fbatch); i++) {
|
||
|
|
struct folio *folio = fbatch.folios[i];
|
||
|
|
|
||
|
|
folio_lock(folio);
|
||
|
|
nilfs_clear_dirty_page(&folio->page, silent);
|
||
|
|
folio_unlock(folio);
|
||
|
|
}
|
||
|
|
folio_batch_release(&fbatch);
|
||
|
|
cond_resched();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* nilfs_clear_dirty_page - discard dirty page
|
||
|
|
* @page: dirty page that will be discarded
|
||
|
|
* @silent: suppress [true] or print [false] warning messages
|
||
|
|
*/
|
||
|
|
void nilfs_clear_dirty_page(struct page *page, bool silent)
|
||
|
|
{
|
||
|
|
struct inode *inode = page->mapping->host;
|
||
|
|
struct super_block *sb = inode->i_sb;
|
||
|
|
|
||
|
|
BUG_ON(!PageLocked(page));
|
||
|
|
|
||
|
|
if (!silent)
|
||
|
|
nilfs_warn(sb, "discard dirty page: offset=%lld, ino=%lu",
|
||
|
|
page_offset(page), inode->i_ino);
|
||
|
|
|
||
|
|
ClearPageUptodate(page);
|
||
|
|
ClearPageMappedToDisk(page);
|
||
|
|
|
||
|
|
if (page_has_buffers(page)) {
|
||
|
|
struct buffer_head *bh, *head;
|
||
|
|
const unsigned long clear_bits =
|
||
|
|
(BIT(BH_Uptodate) | BIT(BH_Dirty) | BIT(BH_Mapped) |
|
||
|
|
BIT(BH_Async_Write) | BIT(BH_NILFS_Volatile) |
|
||
|
|
BIT(BH_NILFS_Checked) | BIT(BH_NILFS_Redirected));
|
||
|
|
|
||
|
|
bh = head = page_buffers(page);
|
||
|
|
do {
|
||
|
|
lock_buffer(bh);
|
||
|
|
if (!silent)
|
||
|
|
nilfs_warn(sb,
|
||
|
|
"discard dirty block: blocknr=%llu, size=%zu",
|
||
|
|
(u64)bh->b_blocknr, bh->b_size);
|
||
|
|
|
||
|
|
set_mask_bits(&bh->b_state, clear_bits, 0);
|
||
|
|
unlock_buffer(bh);
|
||
|
|
} while (bh = bh->b_this_page, bh != head);
|
||
|
|
}
|
||
|
|
|
||
|
|
__nilfs_clear_page_dirty(page);
|
||
|
|
}
|
||
|
|
|
||
|
|
unsigned int nilfs_page_count_clean_buffers(struct page *page,
|
||
|
|
unsigned int from, unsigned int to)
|
||
|
|
{
|
||
|
|
unsigned int block_start, block_end;
|
||
|
|
struct buffer_head *bh, *head;
|
||
|
|
unsigned int nc = 0;
|
||
|
|
|
||
|
|
for (bh = head = page_buffers(page), block_start = 0;
|
||
|
|
bh != head || !block_start;
|
||
|
|
block_start = block_end, bh = bh->b_this_page) {
|
||
|
|
block_end = block_start + bh->b_size;
|
||
|
|
if (block_end > from && block_start < to && !buffer_dirty(bh))
|
||
|
|
nc++;
|
||
|
|
}
|
||
|
|
return nc;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* NILFS2 needs clear_page_dirty() in the following two cases:
|
||
|
|
*
|
||
|
|
* 1) For B-tree node pages and data pages of DAT file, NILFS2 clears dirty
|
||
|
|
* flag of pages when it copies back pages from shadow cache to the
|
||
|
|
* original cache.
|
||
|
|
*
|
||
|
|
* 2) Some B-tree operations like insertion or deletion may dispose buffers
|
||
|
|
* in dirty state, and this needs to cancel the dirty state of their pages.
|
||
|
|
*/
|
||
|
|
int __nilfs_clear_page_dirty(struct page *page)
|
||
|
|
{
|
||
|
|
struct address_space *mapping = page->mapping;
|
||
|
|
|
||
|
|
if (mapping) {
|
||
|
|
xa_lock_irq(&mapping->i_pages);
|
||
|
|
if (test_bit(PG_dirty, &page->flags)) {
|
||
|
|
__xa_clear_mark(&mapping->i_pages, page_index(page),
|
||
|
|
PAGECACHE_TAG_DIRTY);
|
||
|
|
xa_unlock_irq(&mapping->i_pages);
|
||
|
|
return clear_page_dirty_for_io(page);
|
||
|
|
}
|
||
|
|
xa_unlock_irq(&mapping->i_pages);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
return TestClearPageDirty(page);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* nilfs_find_uncommitted_extent - find extent of uncommitted data
|
||
|
|
* @inode: inode
|
||
|
|
* @start_blk: start block offset (in)
|
||
|
|
* @blkoff: start offset of the found extent (out)
|
||
|
|
*
|
||
|
|
* This function searches an extent of buffers marked "delayed" which
|
||
|
|
* starts from a block offset equal to or larger than @start_blk. If
|
||
|
|
* such an extent was found, this will store the start offset in
|
||
|
|
* @blkoff and return its length in blocks. Otherwise, zero is
|
||
|
|
* returned.
|
||
|
|
*/
|
||
|
|
unsigned long nilfs_find_uncommitted_extent(struct inode *inode,
|
||
|
|
sector_t start_blk,
|
||
|
|
sector_t *blkoff)
|
||
|
|
{
|
||
|
|
unsigned int i, nr_folios;
|
||
|
|
pgoff_t index;
|
||
|
|
unsigned long length = 0;
|
||
|
|
struct folio_batch fbatch;
|
||
|
|
struct folio *folio;
|
||
|
|
|
||
|
|
if (inode->i_mapping->nrpages == 0)
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
index = start_blk >> (PAGE_SHIFT - inode->i_blkbits);
|
||
|
|
|
||
|
|
folio_batch_init(&fbatch);
|
||
|
|
|
||
|
|
repeat:
|
||
|
|
nr_folios = filemap_get_folios_contig(inode->i_mapping, &index, ULONG_MAX,
|
||
|
|
&fbatch);
|
||
|
|
if (nr_folios == 0)
|
||
|
|
return length;
|
||
|
|
|
||
|
|
i = 0;
|
||
|
|
do {
|
||
|
|
folio = fbatch.folios[i];
|
||
|
|
|
||
|
|
folio_lock(folio);
|
||
|
|
if (folio_buffers(folio)) {
|
||
|
|
struct buffer_head *bh, *head;
|
||
|
|
sector_t b;
|
||
|
|
|
||
|
|
b = folio->index << (PAGE_SHIFT - inode->i_blkbits);
|
||
|
|
bh = head = folio_buffers(folio);
|
||
|
|
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;
|
||
|
|
}
|
||
|
|
folio_unlock(folio);
|
||
|
|
|
||
|
|
} while (++i < nr_folios);
|
||
|
|
|
||
|
|
folio_batch_release(&fbatch);
|
||
|
|
cond_resched();
|
||
|
|
goto repeat;
|
||
|
|
|
||
|
|
out_locked:
|
||
|
|
folio_unlock(folio);
|
||
|
|
folio_batch_release(&fbatch);
|
||
|
|
return length;
|
||
|
|
}
|