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fd9dc93e36
Userspace translates EEXIST to "File exists" which isn't a very good error message for the problem. "Device or resource busy" is a better indication of what went wrong. Signed-off-by: Matthew Wilcox <willy@infradead.org>
274 lines
6.6 KiB
C
274 lines
6.6 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* btnode.c - NILFS B-tree node cache
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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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* Originally written by Seiji Kihara.
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* Fully revised by Ryusuke Konishi for stabilization and simplification.
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*
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*/
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#include <linux/types.h>
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#include <linux/buffer_head.h>
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#include <linux/mm.h>
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#include <linux/backing-dev.h>
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#include <linux/gfp.h>
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#include "nilfs.h"
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#include "mdt.h"
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#include "dat.h"
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#include "page.h"
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#include "btnode.h"
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void nilfs_btnode_cache_clear(struct address_space *btnc)
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{
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invalidate_mapping_pages(btnc, 0, -1);
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truncate_inode_pages(btnc, 0);
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}
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struct buffer_head *
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nilfs_btnode_create_block(struct address_space *btnc, __u64 blocknr)
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{
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struct inode *inode = NILFS_BTNC_I(btnc);
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struct buffer_head *bh;
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bh = nilfs_grab_buffer(inode, btnc, blocknr, BIT(BH_NILFS_Node));
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if (unlikely(!bh))
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return NULL;
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if (unlikely(buffer_mapped(bh) || buffer_uptodate(bh) ||
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buffer_dirty(bh))) {
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brelse(bh);
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BUG();
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}
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memset(bh->b_data, 0, i_blocksize(inode));
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bh->b_bdev = inode->i_sb->s_bdev;
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bh->b_blocknr = blocknr;
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set_buffer_mapped(bh);
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set_buffer_uptodate(bh);
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unlock_page(bh->b_page);
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put_page(bh->b_page);
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return bh;
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}
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int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
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sector_t pblocknr, int mode, int mode_flags,
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struct buffer_head **pbh, sector_t *submit_ptr)
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{
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struct buffer_head *bh;
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struct inode *inode = NILFS_BTNC_I(btnc);
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struct page *page;
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int err;
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bh = nilfs_grab_buffer(inode, btnc, blocknr, BIT(BH_NILFS_Node));
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if (unlikely(!bh))
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return -ENOMEM;
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err = -EEXIST; /* internal code */
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page = bh->b_page;
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if (buffer_uptodate(bh) || buffer_dirty(bh))
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goto found;
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if (pblocknr == 0) {
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pblocknr = blocknr;
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if (inode->i_ino != NILFS_DAT_INO) {
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struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
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/* blocknr is a virtual block number */
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err = nilfs_dat_translate(nilfs->ns_dat, blocknr,
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&pblocknr);
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if (unlikely(err)) {
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brelse(bh);
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goto out_locked;
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}
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}
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}
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if (mode_flags & REQ_RAHEAD) {
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if (pblocknr != *submit_ptr + 1 || !trylock_buffer(bh)) {
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err = -EBUSY; /* internal code */
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brelse(bh);
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goto out_locked;
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}
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} else { /* mode == READ */
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lock_buffer(bh);
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}
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if (buffer_uptodate(bh)) {
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unlock_buffer(bh);
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err = -EEXIST; /* internal code */
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goto found;
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}
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set_buffer_mapped(bh);
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bh->b_bdev = inode->i_sb->s_bdev;
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bh->b_blocknr = pblocknr; /* set block address for read */
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bh->b_end_io = end_buffer_read_sync;
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get_bh(bh);
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submit_bh(mode, mode_flags, bh);
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bh->b_blocknr = blocknr; /* set back to the given block address */
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*submit_ptr = pblocknr;
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err = 0;
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found:
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*pbh = bh;
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out_locked:
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unlock_page(page);
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put_page(page);
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return err;
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}
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/**
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* nilfs_btnode_delete - delete B-tree node buffer
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* @bh: buffer to be deleted
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*
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* nilfs_btnode_delete() invalidates the specified buffer and delete the page
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* including the buffer if the page gets unbusy.
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*/
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void nilfs_btnode_delete(struct buffer_head *bh)
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{
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struct address_space *mapping;
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struct page *page = bh->b_page;
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pgoff_t index = page_index(page);
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int still_dirty;
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get_page(page);
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lock_page(page);
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wait_on_page_writeback(page);
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nilfs_forget_buffer(bh);
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still_dirty = PageDirty(page);
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mapping = page->mapping;
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unlock_page(page);
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put_page(page);
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if (!still_dirty && mapping)
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invalidate_inode_pages2_range(mapping, index, index);
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}
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/**
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* nilfs_btnode_prepare_change_key
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* prepare to move contents of the block for old key to one of new key.
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* the old buffer will not be removed, but might be reused for new buffer.
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* it might return -ENOMEM because of memory allocation errors,
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* and might return -EIO because of disk read errors.
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*/
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int nilfs_btnode_prepare_change_key(struct address_space *btnc,
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struct nilfs_btnode_chkey_ctxt *ctxt)
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{
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struct buffer_head *obh, *nbh;
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struct inode *inode = NILFS_BTNC_I(btnc);
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__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
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int err;
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if (oldkey == newkey)
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return 0;
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obh = ctxt->bh;
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ctxt->newbh = NULL;
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if (inode->i_blkbits == PAGE_SHIFT) {
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struct page *opage = obh->b_page;
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lock_page(opage);
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retry:
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/* BUG_ON(oldkey != obh->b_page->index); */
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if (unlikely(oldkey != opage->index))
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NILFS_PAGE_BUG(opage,
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"invalid oldkey %lld (newkey=%lld)",
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(unsigned long long)oldkey,
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(unsigned long long)newkey);
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xa_lock_irq(&btnc->i_pages);
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err = __xa_insert(&btnc->i_pages, newkey, opage, GFP_NOFS);
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xa_unlock_irq(&btnc->i_pages);
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/*
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* Note: page->index will not change to newkey until
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* nilfs_btnode_commit_change_key() will be called.
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* To protect the page in intermediate state, the page lock
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* is held.
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*/
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if (!err)
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return 0;
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else if (err != -EBUSY)
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goto failed_unlock;
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err = invalidate_inode_pages2_range(btnc, newkey, newkey);
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if (!err)
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goto retry;
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/* fallback to copy mode */
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unlock_page(opage);
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}
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nbh = nilfs_btnode_create_block(btnc, newkey);
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if (!nbh)
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return -ENOMEM;
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BUG_ON(nbh == obh);
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ctxt->newbh = nbh;
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return 0;
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failed_unlock:
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unlock_page(obh->b_page);
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return err;
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}
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/**
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* nilfs_btnode_commit_change_key
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* commit the change_key operation prepared by prepare_change_key().
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*/
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void nilfs_btnode_commit_change_key(struct address_space *btnc,
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struct nilfs_btnode_chkey_ctxt *ctxt)
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{
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struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh;
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__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
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struct page *opage;
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if (oldkey == newkey)
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return;
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if (nbh == NULL) { /* blocksize == pagesize */
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opage = obh->b_page;
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if (unlikely(oldkey != opage->index))
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NILFS_PAGE_BUG(opage,
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"invalid oldkey %lld (newkey=%lld)",
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(unsigned long long)oldkey,
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(unsigned long long)newkey);
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mark_buffer_dirty(obh);
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xa_lock_irq(&btnc->i_pages);
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__xa_erase(&btnc->i_pages, oldkey);
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__xa_set_mark(&btnc->i_pages, newkey, PAGECACHE_TAG_DIRTY);
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xa_unlock_irq(&btnc->i_pages);
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opage->index = obh->b_blocknr = newkey;
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unlock_page(opage);
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} else {
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nilfs_copy_buffer(nbh, obh);
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mark_buffer_dirty(nbh);
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nbh->b_blocknr = newkey;
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ctxt->bh = nbh;
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nilfs_btnode_delete(obh); /* will decrement bh->b_count */
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}
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}
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/**
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* nilfs_btnode_abort_change_key
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* abort the change_key operation prepared by prepare_change_key().
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*/
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void nilfs_btnode_abort_change_key(struct address_space *btnc,
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struct nilfs_btnode_chkey_ctxt *ctxt)
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{
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struct buffer_head *nbh = ctxt->newbh;
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__u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
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if (oldkey == newkey)
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return;
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if (nbh == NULL) { /* blocksize == pagesize */
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xa_erase_irq(&btnc->i_pages, newkey);
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unlock_page(ctxt->bh->b_page);
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} else
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brelse(nbh);
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}
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