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![Fabio M. De Francesco](/assets/img/avatar_default.png)
kmap() is being deprecated in favor of kmap_local_page(). Two main problems with kmap(): (1) It comes with an overhead as mapping space is restricted and protected by a global lock for synchronization and (2) it also requires global TLB invalidation when the kmap's pool wraps and it might block when the mapping space is fully utilized until a slot becomes available. With kmap_local_page() the mappings are per thread, CPU local, can take page faults, and can be called from any context (including interrupts). It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore, the tasks can be preempted and, when they are scheduled to run again, the kernel virtual addresses are restored and still valid. Since its use in bnode.c is safe everywhere, it should be preferred. Therefore, replace kmap() with kmap_local_page() in bnode.c. Where possible, use the suited standard helpers (memzero_page(), memcpy_page()) instead of open coding kmap_local_page() plus memset() or memcpy(). Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with HIGHMEM64GB enabled. Link: https://lkml.kernel.org/r/20220809203105.26183-3-fmdefrancesco@gmail.com Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com> Suggested-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com> Cc: Bart Van Assche <bvanassche@acm.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Kees Cook <keescook@chromium.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
652 lines
15 KiB
C
652 lines
15 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/fs/hfsplus/bnode.c
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*
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* Copyright (C) 2001
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* Brad Boyer (flar@allandria.com)
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* (C) 2003 Ardis Technologies <roman@ardistech.com>
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*
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* Handle basic btree node operations
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*/
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#include <linux/string.h>
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#include <linux/slab.h>
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#include <linux/pagemap.h>
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#include <linux/fs.h>
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#include <linux/swap.h>
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#include "hfsplus_fs.h"
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#include "hfsplus_raw.h"
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/* Copy a specified range of bytes from the raw data of a node */
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void hfs_bnode_read(struct hfs_bnode *node, void *buf, int off, int len)
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{
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struct page **pagep;
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int l;
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off += node->page_offset;
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pagep = node->page + (off >> PAGE_SHIFT);
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off &= ~PAGE_MASK;
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l = min_t(int, len, PAGE_SIZE - off);
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memcpy_from_page(buf, *pagep, off, l);
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while ((len -= l) != 0) {
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buf += l;
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l = min_t(int, len, PAGE_SIZE);
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memcpy_from_page(buf, *++pagep, 0, l);
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}
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}
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u16 hfs_bnode_read_u16(struct hfs_bnode *node, int off)
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{
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__be16 data;
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/* TODO: optimize later... */
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hfs_bnode_read(node, &data, off, 2);
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return be16_to_cpu(data);
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}
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u8 hfs_bnode_read_u8(struct hfs_bnode *node, int off)
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{
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u8 data;
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/* TODO: optimize later... */
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hfs_bnode_read(node, &data, off, 1);
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return data;
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}
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void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off)
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{
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struct hfs_btree *tree;
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int key_len;
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tree = node->tree;
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if (node->type == HFS_NODE_LEAF ||
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tree->attributes & HFS_TREE_VARIDXKEYS ||
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node->tree->cnid == HFSPLUS_ATTR_CNID)
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key_len = hfs_bnode_read_u16(node, off) + 2;
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else
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key_len = tree->max_key_len + 2;
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hfs_bnode_read(node, key, off, key_len);
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}
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void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len)
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{
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struct page **pagep;
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int l;
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off += node->page_offset;
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pagep = node->page + (off >> PAGE_SHIFT);
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off &= ~PAGE_MASK;
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l = min_t(int, len, PAGE_SIZE - off);
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memcpy_to_page(*pagep, off, buf, l);
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set_page_dirty(*pagep);
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while ((len -= l) != 0) {
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buf += l;
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l = min_t(int, len, PAGE_SIZE);
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memcpy_to_page(*++pagep, 0, buf, l);
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set_page_dirty(*pagep);
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}
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}
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void hfs_bnode_write_u16(struct hfs_bnode *node, int off, u16 data)
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{
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__be16 v = cpu_to_be16(data);
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/* TODO: optimize later... */
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hfs_bnode_write(node, &v, off, 2);
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}
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void hfs_bnode_clear(struct hfs_bnode *node, int off, int len)
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{
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struct page **pagep;
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int l;
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off += node->page_offset;
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pagep = node->page + (off >> PAGE_SHIFT);
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off &= ~PAGE_MASK;
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l = min_t(int, len, PAGE_SIZE - off);
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memzero_page(*pagep, off, l);
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set_page_dirty(*pagep);
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while ((len -= l) != 0) {
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l = min_t(int, len, PAGE_SIZE);
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memzero_page(*++pagep, 0, l);
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set_page_dirty(*pagep);
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}
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}
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void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst,
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struct hfs_bnode *src_node, int src, int len)
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{
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struct page **src_page, **dst_page;
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int l;
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hfs_dbg(BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len);
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if (!len)
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return;
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src += src_node->page_offset;
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dst += dst_node->page_offset;
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src_page = src_node->page + (src >> PAGE_SHIFT);
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src &= ~PAGE_MASK;
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dst_page = dst_node->page + (dst >> PAGE_SHIFT);
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dst &= ~PAGE_MASK;
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if (src == dst) {
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l = min_t(int, len, PAGE_SIZE - src);
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memcpy_page(*dst_page, src, *src_page, src, l);
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set_page_dirty(*dst_page);
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while ((len -= l) != 0) {
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l = min_t(int, len, PAGE_SIZE);
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memcpy_page(*++dst_page, 0, *++src_page, 0, l);
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set_page_dirty(*dst_page);
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}
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} else {
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void *src_ptr, *dst_ptr;
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do {
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dst_ptr = kmap_local_page(*dst_page) + dst;
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src_ptr = kmap_local_page(*src_page) + src;
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if (PAGE_SIZE - src < PAGE_SIZE - dst) {
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l = PAGE_SIZE - src;
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src = 0;
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dst += l;
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} else {
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l = PAGE_SIZE - dst;
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src += l;
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dst = 0;
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}
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l = min(len, l);
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memcpy(dst_ptr, src_ptr, l);
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kunmap_local(src_ptr);
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set_page_dirty(*dst_page);
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kunmap_local(dst_ptr);
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if (!dst)
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dst_page++;
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else
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src_page++;
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} while ((len -= l));
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}
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}
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void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len)
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{
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struct page **src_page, **dst_page;
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void *src_ptr, *dst_ptr;
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int l;
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hfs_dbg(BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len);
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if (!len)
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return;
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src += node->page_offset;
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dst += node->page_offset;
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if (dst > src) {
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src += len - 1;
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src_page = node->page + (src >> PAGE_SHIFT);
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src = (src & ~PAGE_MASK) + 1;
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dst += len - 1;
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dst_page = node->page + (dst >> PAGE_SHIFT);
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dst = (dst & ~PAGE_MASK) + 1;
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if (src == dst) {
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while (src < len) {
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dst_ptr = kmap_local_page(*dst_page);
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src_ptr = kmap_local_page(*src_page);
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memmove(dst_ptr, src_ptr, src);
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kunmap_local(src_ptr);
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set_page_dirty(*dst_page);
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kunmap_local(dst_ptr);
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len -= src;
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src = PAGE_SIZE;
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src_page--;
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dst_page--;
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}
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src -= len;
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dst_ptr = kmap_local_page(*dst_page);
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src_ptr = kmap_local_page(*src_page);
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memmove(dst_ptr + src, src_ptr + src, len);
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kunmap_local(src_ptr);
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set_page_dirty(*dst_page);
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kunmap_local(dst_ptr);
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} else {
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do {
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dst_ptr = kmap_local_page(*dst_page) + dst;
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src_ptr = kmap_local_page(*src_page) + src;
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if (src < dst) {
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l = src;
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src = PAGE_SIZE;
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dst -= l;
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} else {
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l = dst;
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src -= l;
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dst = PAGE_SIZE;
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}
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l = min(len, l);
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memmove(dst_ptr - l, src_ptr - l, l);
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kunmap_local(src_ptr);
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set_page_dirty(*dst_page);
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kunmap_local(dst_ptr);
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if (dst == PAGE_SIZE)
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dst_page--;
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else
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src_page--;
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} while ((len -= l));
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}
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} else {
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src_page = node->page + (src >> PAGE_SHIFT);
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src &= ~PAGE_MASK;
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dst_page = node->page + (dst >> PAGE_SHIFT);
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dst &= ~PAGE_MASK;
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if (src == dst) {
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l = min_t(int, len, PAGE_SIZE - src);
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dst_ptr = kmap_local_page(*dst_page) + src;
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src_ptr = kmap_local_page(*src_page) + src;
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memmove(dst_ptr, src_ptr, l);
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kunmap_local(src_ptr);
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set_page_dirty(*dst_page);
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kunmap_local(dst_ptr);
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while ((len -= l) != 0) {
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l = min_t(int, len, PAGE_SIZE);
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dst_ptr = kmap_local_page(*++dst_page);
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src_ptr = kmap_local_page(*++src_page);
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memmove(dst_ptr, src_ptr, l);
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kunmap_local(src_ptr);
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set_page_dirty(*dst_page);
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kunmap_local(dst_ptr);
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}
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} else {
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do {
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dst_ptr = kmap_local_page(*dst_page) + dst;
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src_ptr = kmap_local_page(*src_page) + src;
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if (PAGE_SIZE - src <
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PAGE_SIZE - dst) {
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l = PAGE_SIZE - src;
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src = 0;
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dst += l;
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} else {
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l = PAGE_SIZE - dst;
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src += l;
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dst = 0;
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}
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l = min(len, l);
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memmove(dst_ptr, src_ptr, l);
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kunmap_local(src_ptr);
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set_page_dirty(*dst_page);
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kunmap_local(dst_ptr);
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if (!dst)
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dst_page++;
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else
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src_page++;
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} while ((len -= l));
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}
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}
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}
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void hfs_bnode_dump(struct hfs_bnode *node)
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{
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struct hfs_bnode_desc desc;
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__be32 cnid;
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int i, off, key_off;
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hfs_dbg(BNODE_MOD, "bnode: %d\n", node->this);
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hfs_bnode_read(node, &desc, 0, sizeof(desc));
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hfs_dbg(BNODE_MOD, "%d, %d, %d, %d, %d\n",
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be32_to_cpu(desc.next), be32_to_cpu(desc.prev),
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desc.type, desc.height, be16_to_cpu(desc.num_recs));
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off = node->tree->node_size - 2;
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for (i = be16_to_cpu(desc.num_recs); i >= 0; off -= 2, i--) {
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key_off = hfs_bnode_read_u16(node, off);
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hfs_dbg(BNODE_MOD, " %d", key_off);
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if (i && node->type == HFS_NODE_INDEX) {
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int tmp;
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if (node->tree->attributes & HFS_TREE_VARIDXKEYS ||
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node->tree->cnid == HFSPLUS_ATTR_CNID)
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tmp = hfs_bnode_read_u16(node, key_off) + 2;
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else
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tmp = node->tree->max_key_len + 2;
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hfs_dbg_cont(BNODE_MOD, " (%d", tmp);
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hfs_bnode_read(node, &cnid, key_off + tmp, 4);
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hfs_dbg_cont(BNODE_MOD, ",%d)", be32_to_cpu(cnid));
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} else if (i && node->type == HFS_NODE_LEAF) {
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int tmp;
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tmp = hfs_bnode_read_u16(node, key_off);
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hfs_dbg_cont(BNODE_MOD, " (%d)", tmp);
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}
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}
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hfs_dbg_cont(BNODE_MOD, "\n");
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}
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void hfs_bnode_unlink(struct hfs_bnode *node)
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{
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struct hfs_btree *tree;
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struct hfs_bnode *tmp;
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__be32 cnid;
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tree = node->tree;
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if (node->prev) {
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tmp = hfs_bnode_find(tree, node->prev);
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if (IS_ERR(tmp))
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return;
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tmp->next = node->next;
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cnid = cpu_to_be32(tmp->next);
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hfs_bnode_write(tmp, &cnid,
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offsetof(struct hfs_bnode_desc, next), 4);
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hfs_bnode_put(tmp);
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} else if (node->type == HFS_NODE_LEAF)
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tree->leaf_head = node->next;
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if (node->next) {
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tmp = hfs_bnode_find(tree, node->next);
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if (IS_ERR(tmp))
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return;
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tmp->prev = node->prev;
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cnid = cpu_to_be32(tmp->prev);
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hfs_bnode_write(tmp, &cnid,
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offsetof(struct hfs_bnode_desc, prev), 4);
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hfs_bnode_put(tmp);
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} else if (node->type == HFS_NODE_LEAF)
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tree->leaf_tail = node->prev;
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/* move down? */
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if (!node->prev && !node->next)
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hfs_dbg(BNODE_MOD, "hfs_btree_del_level\n");
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if (!node->parent) {
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tree->root = 0;
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tree->depth = 0;
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}
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set_bit(HFS_BNODE_DELETED, &node->flags);
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}
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static inline int hfs_bnode_hash(u32 num)
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{
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num = (num >> 16) + num;
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num += num >> 8;
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return num & (NODE_HASH_SIZE - 1);
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}
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struct hfs_bnode *hfs_bnode_findhash(struct hfs_btree *tree, u32 cnid)
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{
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struct hfs_bnode *node;
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if (cnid >= tree->node_count) {
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pr_err("request for non-existent node %d in B*Tree\n",
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cnid);
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return NULL;
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}
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for (node = tree->node_hash[hfs_bnode_hash(cnid)];
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node; node = node->next_hash)
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if (node->this == cnid)
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return node;
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return NULL;
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}
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static struct hfs_bnode *__hfs_bnode_create(struct hfs_btree *tree, u32 cnid)
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{
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struct hfs_bnode *node, *node2;
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struct address_space *mapping;
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struct page *page;
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int size, block, i, hash;
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loff_t off;
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if (cnid >= tree->node_count) {
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pr_err("request for non-existent node %d in B*Tree\n",
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cnid);
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return NULL;
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}
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size = sizeof(struct hfs_bnode) + tree->pages_per_bnode *
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sizeof(struct page *);
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node = kzalloc(size, GFP_KERNEL);
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if (!node)
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return NULL;
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node->tree = tree;
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node->this = cnid;
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set_bit(HFS_BNODE_NEW, &node->flags);
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atomic_set(&node->refcnt, 1);
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hfs_dbg(BNODE_REFS, "new_node(%d:%d): 1\n",
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node->tree->cnid, node->this);
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init_waitqueue_head(&node->lock_wq);
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spin_lock(&tree->hash_lock);
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node2 = hfs_bnode_findhash(tree, cnid);
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if (!node2) {
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hash = hfs_bnode_hash(cnid);
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node->next_hash = tree->node_hash[hash];
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tree->node_hash[hash] = node;
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tree->node_hash_cnt++;
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} else {
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spin_unlock(&tree->hash_lock);
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kfree(node);
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wait_event(node2->lock_wq,
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!test_bit(HFS_BNODE_NEW, &node2->flags));
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return node2;
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}
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spin_unlock(&tree->hash_lock);
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mapping = tree->inode->i_mapping;
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off = (loff_t)cnid << tree->node_size_shift;
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block = off >> PAGE_SHIFT;
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node->page_offset = off & ~PAGE_MASK;
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for (i = 0; i < tree->pages_per_bnode; block++, i++) {
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page = read_mapping_page(mapping, block, NULL);
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if (IS_ERR(page))
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goto fail;
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node->page[i] = page;
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}
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return node;
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fail:
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set_bit(HFS_BNODE_ERROR, &node->flags);
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return node;
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}
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void hfs_bnode_unhash(struct hfs_bnode *node)
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{
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struct hfs_bnode **p;
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hfs_dbg(BNODE_REFS, "remove_node(%d:%d): %d\n",
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node->tree->cnid, node->this, atomic_read(&node->refcnt));
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for (p = &node->tree->node_hash[hfs_bnode_hash(node->this)];
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*p && *p != node; p = &(*p)->next_hash)
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;
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BUG_ON(!*p);
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*p = node->next_hash;
|
|
node->tree->node_hash_cnt--;
|
|
}
|
|
|
|
/* Load a particular node out of a tree */
|
|
struct hfs_bnode *hfs_bnode_find(struct hfs_btree *tree, u32 num)
|
|
{
|
|
struct hfs_bnode *node;
|
|
struct hfs_bnode_desc *desc;
|
|
int i, rec_off, off, next_off;
|
|
int entry_size, key_size;
|
|
|
|
spin_lock(&tree->hash_lock);
|
|
node = hfs_bnode_findhash(tree, num);
|
|
if (node) {
|
|
hfs_bnode_get(node);
|
|
spin_unlock(&tree->hash_lock);
|
|
wait_event(node->lock_wq,
|
|
!test_bit(HFS_BNODE_NEW, &node->flags));
|
|
if (test_bit(HFS_BNODE_ERROR, &node->flags))
|
|
goto node_error;
|
|
return node;
|
|
}
|
|
spin_unlock(&tree->hash_lock);
|
|
node = __hfs_bnode_create(tree, num);
|
|
if (!node)
|
|
return ERR_PTR(-ENOMEM);
|
|
if (test_bit(HFS_BNODE_ERROR, &node->flags))
|
|
goto node_error;
|
|
if (!test_bit(HFS_BNODE_NEW, &node->flags))
|
|
return node;
|
|
|
|
desc = (struct hfs_bnode_desc *)(kmap_local_page(node->page[0]) +
|
|
node->page_offset);
|
|
node->prev = be32_to_cpu(desc->prev);
|
|
node->next = be32_to_cpu(desc->next);
|
|
node->num_recs = be16_to_cpu(desc->num_recs);
|
|
node->type = desc->type;
|
|
node->height = desc->height;
|
|
kunmap_local(desc);
|
|
|
|
switch (node->type) {
|
|
case HFS_NODE_HEADER:
|
|
case HFS_NODE_MAP:
|
|
if (node->height != 0)
|
|
goto node_error;
|
|
break;
|
|
case HFS_NODE_LEAF:
|
|
if (node->height != 1)
|
|
goto node_error;
|
|
break;
|
|
case HFS_NODE_INDEX:
|
|
if (node->height <= 1 || node->height > tree->depth)
|
|
goto node_error;
|
|
break;
|
|
default:
|
|
goto node_error;
|
|
}
|
|
|
|
rec_off = tree->node_size - 2;
|
|
off = hfs_bnode_read_u16(node, rec_off);
|
|
if (off != sizeof(struct hfs_bnode_desc))
|
|
goto node_error;
|
|
for (i = 1; i <= node->num_recs; off = next_off, i++) {
|
|
rec_off -= 2;
|
|
next_off = hfs_bnode_read_u16(node, rec_off);
|
|
if (next_off <= off ||
|
|
next_off > tree->node_size ||
|
|
next_off & 1)
|
|
goto node_error;
|
|
entry_size = next_off - off;
|
|
if (node->type != HFS_NODE_INDEX &&
|
|
node->type != HFS_NODE_LEAF)
|
|
continue;
|
|
key_size = hfs_bnode_read_u16(node, off) + 2;
|
|
if (key_size >= entry_size || key_size & 1)
|
|
goto node_error;
|
|
}
|
|
clear_bit(HFS_BNODE_NEW, &node->flags);
|
|
wake_up(&node->lock_wq);
|
|
return node;
|
|
|
|
node_error:
|
|
set_bit(HFS_BNODE_ERROR, &node->flags);
|
|
clear_bit(HFS_BNODE_NEW, &node->flags);
|
|
wake_up(&node->lock_wq);
|
|
hfs_bnode_put(node);
|
|
return ERR_PTR(-EIO);
|
|
}
|
|
|
|
void hfs_bnode_free(struct hfs_bnode *node)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < node->tree->pages_per_bnode; i++)
|
|
if (node->page[i])
|
|
put_page(node->page[i]);
|
|
kfree(node);
|
|
}
|
|
|
|
struct hfs_bnode *hfs_bnode_create(struct hfs_btree *tree, u32 num)
|
|
{
|
|
struct hfs_bnode *node;
|
|
struct page **pagep;
|
|
int i;
|
|
|
|
spin_lock(&tree->hash_lock);
|
|
node = hfs_bnode_findhash(tree, num);
|
|
spin_unlock(&tree->hash_lock);
|
|
if (node) {
|
|
pr_crit("new node %u already hashed?\n", num);
|
|
WARN_ON(1);
|
|
return node;
|
|
}
|
|
node = __hfs_bnode_create(tree, num);
|
|
if (!node)
|
|
return ERR_PTR(-ENOMEM);
|
|
if (test_bit(HFS_BNODE_ERROR, &node->flags)) {
|
|
hfs_bnode_put(node);
|
|
return ERR_PTR(-EIO);
|
|
}
|
|
|
|
pagep = node->page;
|
|
memzero_page(*pagep, node->page_offset,
|
|
min_t(int, PAGE_SIZE, tree->node_size));
|
|
set_page_dirty(*pagep);
|
|
for (i = 1; i < tree->pages_per_bnode; i++) {
|
|
memzero_page(*++pagep, 0, PAGE_SIZE);
|
|
set_page_dirty(*pagep);
|
|
}
|
|
clear_bit(HFS_BNODE_NEW, &node->flags);
|
|
wake_up(&node->lock_wq);
|
|
|
|
return node;
|
|
}
|
|
|
|
void hfs_bnode_get(struct hfs_bnode *node)
|
|
{
|
|
if (node) {
|
|
atomic_inc(&node->refcnt);
|
|
hfs_dbg(BNODE_REFS, "get_node(%d:%d): %d\n",
|
|
node->tree->cnid, node->this,
|
|
atomic_read(&node->refcnt));
|
|
}
|
|
}
|
|
|
|
/* Dispose of resources used by a node */
|
|
void hfs_bnode_put(struct hfs_bnode *node)
|
|
{
|
|
if (node) {
|
|
struct hfs_btree *tree = node->tree;
|
|
int i;
|
|
|
|
hfs_dbg(BNODE_REFS, "put_node(%d:%d): %d\n",
|
|
node->tree->cnid, node->this,
|
|
atomic_read(&node->refcnt));
|
|
BUG_ON(!atomic_read(&node->refcnt));
|
|
if (!atomic_dec_and_lock(&node->refcnt, &tree->hash_lock))
|
|
return;
|
|
for (i = 0; i < tree->pages_per_bnode; i++) {
|
|
if (!node->page[i])
|
|
continue;
|
|
mark_page_accessed(node->page[i]);
|
|
}
|
|
|
|
if (test_bit(HFS_BNODE_DELETED, &node->flags)) {
|
|
hfs_bnode_unhash(node);
|
|
spin_unlock(&tree->hash_lock);
|
|
if (hfs_bnode_need_zeroout(tree))
|
|
hfs_bnode_clear(node, 0, tree->node_size);
|
|
hfs_bmap_free(node);
|
|
hfs_bnode_free(node);
|
|
return;
|
|
}
|
|
spin_unlock(&tree->hash_lock);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Unused nodes have to be zeroed if this is the catalog tree and
|
|
* a corresponding flag in the volume header is set.
|
|
*/
|
|
bool hfs_bnode_need_zeroout(struct hfs_btree *tree)
|
|
{
|
|
struct super_block *sb = tree->inode->i_sb;
|
|
struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
|
|
const u32 volume_attr = be32_to_cpu(sbi->s_vhdr->attributes);
|
|
|
|
return tree->cnid == HFSPLUS_CAT_CNID &&
|
|
volume_attr & HFSPLUS_VOL_UNUSED_NODE_FIX;
|
|
}
|