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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 09:19:51 +00:00
![Fabio M. De Francesco](/assets/img/avatar_default.png)
kmap() is being deprecated in favor of kmap_local_page(). There are 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 are still valid. Since its use in btree.c is safe everywhere, it should be preferred. Therefore, replace kmap() with kmap_local_page() in btree.c. Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with HIGHMEM64GB enabled. Link: https://lkml.kernel.org/r/20220809203105.26183-5-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>
512 lines
12 KiB
C
512 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/fs/hfsplus/btree.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 opening/closing btree
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*/
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#include <linux/slab.h>
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#include <linux/pagemap.h>
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#include <linux/log2.h>
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#include "hfsplus_fs.h"
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#include "hfsplus_raw.h"
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/*
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* Initial source code of clump size calculation is gotten
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* from http://opensource.apple.com/tarballs/diskdev_cmds/
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*/
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#define CLUMP_ENTRIES 15
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static short clumptbl[CLUMP_ENTRIES * 3] = {
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/*
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* Volume Attributes Catalog Extents
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* Size Clump (MB) Clump (MB) Clump (MB)
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*/
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/* 1GB */ 4, 4, 4,
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/* 2GB */ 6, 6, 4,
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/* 4GB */ 8, 8, 4,
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/* 8GB */ 11, 11, 5,
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/*
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* For volumes 16GB and larger, we want to make sure that a full OS
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* install won't require fragmentation of the Catalog or Attributes
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* B-trees. We do this by making the clump sizes sufficiently large,
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* and by leaving a gap after the B-trees for them to grow into.
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*
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* For SnowLeopard 10A298, a FullNetInstall with all packages selected
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* results in:
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* Catalog B-tree Header
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* nodeSize: 8192
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* totalNodes: 31616
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* freeNodes: 1978
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* (used = 231.55 MB)
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* Attributes B-tree Header
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* nodeSize: 8192
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* totalNodes: 63232
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* freeNodes: 958
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* (used = 486.52 MB)
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*
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* We also want Time Machine backup volumes to have a sufficiently
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* large clump size to reduce fragmentation.
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*
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* The series of numbers for Catalog and Attribute form a geometric
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* series. For Catalog (16GB to 512GB), each term is 8**(1/5) times
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* the previous term. For Attributes (16GB to 512GB), each term is
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* 4**(1/5) times the previous term. For 1TB to 16TB, each term is
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* 2**(1/5) times the previous term.
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*/
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/* 16GB */ 64, 32, 5,
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/* 32GB */ 84, 49, 6,
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/* 64GB */ 111, 74, 7,
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/* 128GB */ 147, 111, 8,
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/* 256GB */ 194, 169, 9,
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/* 512GB */ 256, 256, 11,
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/* 1TB */ 294, 294, 14,
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/* 2TB */ 338, 338, 16,
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/* 4TB */ 388, 388, 20,
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/* 8TB */ 446, 446, 25,
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/* 16TB */ 512, 512, 32
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};
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u32 hfsplus_calc_btree_clump_size(u32 block_size, u32 node_size,
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u64 sectors, int file_id)
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{
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u32 mod = max(node_size, block_size);
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u32 clump_size;
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int column;
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int i;
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/* Figure out which column of the above table to use for this file. */
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switch (file_id) {
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case HFSPLUS_ATTR_CNID:
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column = 0;
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break;
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case HFSPLUS_CAT_CNID:
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column = 1;
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break;
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default:
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column = 2;
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break;
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}
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/*
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* The default clump size is 0.8% of the volume size. And
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* it must also be a multiple of the node and block size.
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*/
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if (sectors < 0x200000) {
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clump_size = sectors << 2; /* 0.8 % */
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if (clump_size < (8 * node_size))
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clump_size = 8 * node_size;
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} else {
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/* turn exponent into table index... */
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for (i = 0, sectors = sectors >> 22;
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sectors && (i < CLUMP_ENTRIES - 1);
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++i, sectors = sectors >> 1) {
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/* empty body */
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}
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clump_size = clumptbl[column + (i) * 3] * 1024 * 1024;
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}
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/*
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* Round the clump size to a multiple of node and block size.
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* NOTE: This rounds down.
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*/
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clump_size /= mod;
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clump_size *= mod;
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/*
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* Rounding down could have rounded down to 0 if the block size was
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* greater than the clump size. If so, just use one block or node.
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*/
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if (clump_size == 0)
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clump_size = mod;
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return clump_size;
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}
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/* Get a reference to a B*Tree and do some initial checks */
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struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id)
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{
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struct hfs_btree *tree;
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struct hfs_btree_header_rec *head;
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struct address_space *mapping;
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struct inode *inode;
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struct page *page;
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unsigned int size;
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tree = kzalloc(sizeof(*tree), GFP_KERNEL);
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if (!tree)
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return NULL;
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mutex_init(&tree->tree_lock);
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spin_lock_init(&tree->hash_lock);
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tree->sb = sb;
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tree->cnid = id;
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inode = hfsplus_iget(sb, id);
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if (IS_ERR(inode))
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goto free_tree;
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tree->inode = inode;
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if (!HFSPLUS_I(tree->inode)->first_blocks) {
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pr_err("invalid btree extent records (0 size)\n");
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goto free_inode;
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}
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mapping = tree->inode->i_mapping;
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page = read_mapping_page(mapping, 0, NULL);
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if (IS_ERR(page))
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goto free_inode;
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/* Load the header */
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head = (struct hfs_btree_header_rec *)(kmap_local_page(page) +
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sizeof(struct hfs_bnode_desc));
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tree->root = be32_to_cpu(head->root);
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tree->leaf_count = be32_to_cpu(head->leaf_count);
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tree->leaf_head = be32_to_cpu(head->leaf_head);
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tree->leaf_tail = be32_to_cpu(head->leaf_tail);
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tree->node_count = be32_to_cpu(head->node_count);
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tree->free_nodes = be32_to_cpu(head->free_nodes);
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tree->attributes = be32_to_cpu(head->attributes);
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tree->node_size = be16_to_cpu(head->node_size);
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tree->max_key_len = be16_to_cpu(head->max_key_len);
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tree->depth = be16_to_cpu(head->depth);
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/* Verify the tree and set the correct compare function */
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switch (id) {
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case HFSPLUS_EXT_CNID:
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if (tree->max_key_len != HFSPLUS_EXT_KEYLEN - sizeof(u16)) {
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pr_err("invalid extent max_key_len %d\n",
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tree->max_key_len);
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goto fail_page;
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}
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if (tree->attributes & HFS_TREE_VARIDXKEYS) {
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pr_err("invalid extent btree flag\n");
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goto fail_page;
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}
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tree->keycmp = hfsplus_ext_cmp_key;
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break;
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case HFSPLUS_CAT_CNID:
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if (tree->max_key_len != HFSPLUS_CAT_KEYLEN - sizeof(u16)) {
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pr_err("invalid catalog max_key_len %d\n",
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tree->max_key_len);
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goto fail_page;
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}
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if (!(tree->attributes & HFS_TREE_VARIDXKEYS)) {
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pr_err("invalid catalog btree flag\n");
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goto fail_page;
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}
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if (test_bit(HFSPLUS_SB_HFSX, &HFSPLUS_SB(sb)->flags) &&
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(head->key_type == HFSPLUS_KEY_BINARY))
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tree->keycmp = hfsplus_cat_bin_cmp_key;
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else {
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tree->keycmp = hfsplus_cat_case_cmp_key;
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set_bit(HFSPLUS_SB_CASEFOLD, &HFSPLUS_SB(sb)->flags);
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}
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break;
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case HFSPLUS_ATTR_CNID:
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if (tree->max_key_len != HFSPLUS_ATTR_KEYLEN - sizeof(u16)) {
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pr_err("invalid attributes max_key_len %d\n",
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tree->max_key_len);
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goto fail_page;
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}
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tree->keycmp = hfsplus_attr_bin_cmp_key;
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break;
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default:
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pr_err("unknown B*Tree requested\n");
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goto fail_page;
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}
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if (!(tree->attributes & HFS_TREE_BIGKEYS)) {
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pr_err("invalid btree flag\n");
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goto fail_page;
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}
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size = tree->node_size;
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if (!is_power_of_2(size))
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goto fail_page;
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if (!tree->node_count)
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goto fail_page;
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tree->node_size_shift = ffs(size) - 1;
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tree->pages_per_bnode =
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(tree->node_size + PAGE_SIZE - 1) >>
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PAGE_SHIFT;
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kunmap_local(head);
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put_page(page);
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return tree;
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fail_page:
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kunmap_local(head);
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put_page(page);
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free_inode:
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tree->inode->i_mapping->a_ops = &hfsplus_aops;
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iput(tree->inode);
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free_tree:
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kfree(tree);
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return NULL;
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}
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/* Release resources used by a btree */
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void hfs_btree_close(struct hfs_btree *tree)
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{
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struct hfs_bnode *node;
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int i;
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if (!tree)
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return;
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for (i = 0; i < NODE_HASH_SIZE; i++) {
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while ((node = tree->node_hash[i])) {
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tree->node_hash[i] = node->next_hash;
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if (atomic_read(&node->refcnt))
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pr_crit("node %d:%d "
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"still has %d user(s)!\n",
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node->tree->cnid, node->this,
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atomic_read(&node->refcnt));
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hfs_bnode_free(node);
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tree->node_hash_cnt--;
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}
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}
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iput(tree->inode);
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kfree(tree);
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}
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int hfs_btree_write(struct hfs_btree *tree)
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{
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struct hfs_btree_header_rec *head;
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struct hfs_bnode *node;
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struct page *page;
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node = hfs_bnode_find(tree, 0);
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if (IS_ERR(node))
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/* panic? */
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return -EIO;
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/* Load the header */
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page = node->page[0];
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head = (struct hfs_btree_header_rec *)(kmap_local_page(page) +
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sizeof(struct hfs_bnode_desc));
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head->root = cpu_to_be32(tree->root);
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head->leaf_count = cpu_to_be32(tree->leaf_count);
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head->leaf_head = cpu_to_be32(tree->leaf_head);
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head->leaf_tail = cpu_to_be32(tree->leaf_tail);
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head->node_count = cpu_to_be32(tree->node_count);
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head->free_nodes = cpu_to_be32(tree->free_nodes);
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head->attributes = cpu_to_be32(tree->attributes);
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head->depth = cpu_to_be16(tree->depth);
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kunmap_local(head);
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set_page_dirty(page);
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hfs_bnode_put(node);
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return 0;
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}
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static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
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{
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struct hfs_btree *tree = prev->tree;
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struct hfs_bnode *node;
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struct hfs_bnode_desc desc;
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__be32 cnid;
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node = hfs_bnode_create(tree, idx);
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if (IS_ERR(node))
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return node;
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tree->free_nodes--;
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prev->next = idx;
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cnid = cpu_to_be32(idx);
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hfs_bnode_write(prev, &cnid, offsetof(struct hfs_bnode_desc, next), 4);
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node->type = HFS_NODE_MAP;
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node->num_recs = 1;
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hfs_bnode_clear(node, 0, tree->node_size);
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desc.next = 0;
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desc.prev = 0;
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desc.type = HFS_NODE_MAP;
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desc.height = 0;
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desc.num_recs = cpu_to_be16(1);
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desc.reserved = 0;
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hfs_bnode_write(node, &desc, 0, sizeof(desc));
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hfs_bnode_write_u16(node, 14, 0x8000);
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hfs_bnode_write_u16(node, tree->node_size - 2, 14);
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hfs_bnode_write_u16(node, tree->node_size - 4, tree->node_size - 6);
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return node;
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}
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/* Make sure @tree has enough space for the @rsvd_nodes */
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int hfs_bmap_reserve(struct hfs_btree *tree, int rsvd_nodes)
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{
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struct inode *inode = tree->inode;
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struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
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u32 count;
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int res;
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if (rsvd_nodes <= 0)
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return 0;
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while (tree->free_nodes < rsvd_nodes) {
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res = hfsplus_file_extend(inode, hfs_bnode_need_zeroout(tree));
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if (res)
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return res;
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hip->phys_size = inode->i_size =
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(loff_t)hip->alloc_blocks <<
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HFSPLUS_SB(tree->sb)->alloc_blksz_shift;
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hip->fs_blocks =
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hip->alloc_blocks << HFSPLUS_SB(tree->sb)->fs_shift;
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inode_set_bytes(inode, inode->i_size);
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count = inode->i_size >> tree->node_size_shift;
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tree->free_nodes += count - tree->node_count;
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tree->node_count = count;
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}
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return 0;
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}
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struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
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{
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struct hfs_bnode *node, *next_node;
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struct page **pagep;
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u32 nidx, idx;
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unsigned off;
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u16 off16;
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u16 len;
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u8 *data, byte, m;
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int i, res;
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res = hfs_bmap_reserve(tree, 1);
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if (res)
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return ERR_PTR(res);
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nidx = 0;
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node = hfs_bnode_find(tree, nidx);
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if (IS_ERR(node))
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return node;
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len = hfs_brec_lenoff(node, 2, &off16);
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off = off16;
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off += node->page_offset;
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pagep = node->page + (off >> PAGE_SHIFT);
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data = kmap_local_page(*pagep);
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off &= ~PAGE_MASK;
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idx = 0;
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for (;;) {
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while (len) {
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byte = data[off];
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if (byte != 0xff) {
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for (m = 0x80, i = 0; i < 8; m >>= 1, i++) {
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if (!(byte & m)) {
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idx += i;
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data[off] |= m;
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set_page_dirty(*pagep);
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kunmap_local(data);
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tree->free_nodes--;
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mark_inode_dirty(tree->inode);
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hfs_bnode_put(node);
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return hfs_bnode_create(tree,
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idx);
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}
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}
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}
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if (++off >= PAGE_SIZE) {
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kunmap_local(data);
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data = kmap_local_page(*++pagep);
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off = 0;
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}
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idx += 8;
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len--;
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}
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kunmap_local(data);
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nidx = node->next;
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if (!nidx) {
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hfs_dbg(BNODE_MOD, "create new bmap node\n");
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next_node = hfs_bmap_new_bmap(node, idx);
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} else
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next_node = hfs_bnode_find(tree, nidx);
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hfs_bnode_put(node);
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if (IS_ERR(next_node))
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return next_node;
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node = next_node;
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len = hfs_brec_lenoff(node, 0, &off16);
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off = off16;
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off += node->page_offset;
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pagep = node->page + (off >> PAGE_SHIFT);
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data = kmap_local_page(*pagep);
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off &= ~PAGE_MASK;
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}
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}
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void hfs_bmap_free(struct hfs_bnode *node)
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{
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struct hfs_btree *tree;
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struct page *page;
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u16 off, len;
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u32 nidx;
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u8 *data, byte, m;
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hfs_dbg(BNODE_MOD, "btree_free_node: %u\n", node->this);
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BUG_ON(!node->this);
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tree = node->tree;
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nidx = node->this;
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node = hfs_bnode_find(tree, 0);
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if (IS_ERR(node))
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return;
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len = hfs_brec_lenoff(node, 2, &off);
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while (nidx >= len * 8) {
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u32 i;
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nidx -= len * 8;
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i = node->next;
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if (!i) {
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/* panic */;
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pr_crit("unable to free bnode %u. "
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"bmap not found!\n",
|
|
node->this);
|
|
hfs_bnode_put(node);
|
|
return;
|
|
}
|
|
hfs_bnode_put(node);
|
|
node = hfs_bnode_find(tree, i);
|
|
if (IS_ERR(node))
|
|
return;
|
|
if (node->type != HFS_NODE_MAP) {
|
|
/* panic */;
|
|
pr_crit("invalid bmap found! "
|
|
"(%u,%d)\n",
|
|
node->this, node->type);
|
|
hfs_bnode_put(node);
|
|
return;
|
|
}
|
|
len = hfs_brec_lenoff(node, 0, &off);
|
|
}
|
|
off += node->page_offset + nidx / 8;
|
|
page = node->page[off >> PAGE_SHIFT];
|
|
data = kmap_local_page(page);
|
|
off &= ~PAGE_MASK;
|
|
m = 1 << (~nidx & 7);
|
|
byte = data[off];
|
|
if (!(byte & m)) {
|
|
pr_crit("trying to free free bnode "
|
|
"%u(%d)\n",
|
|
node->this, node->type);
|
|
kunmap_local(data);
|
|
hfs_bnode_put(node);
|
|
return;
|
|
}
|
|
data[off] = byte & ~m;
|
|
set_page_dirty(page);
|
|
kunmap_local(data);
|
|
hfs_bnode_put(node);
|
|
tree->free_nodes++;
|
|
mark_inode_dirty(tree->inode);
|
|
}
|