diff options
author | Namjae Jeon <namjae.jeon@samsung.com> | 2020-03-02 15:21:38 +0900 |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2020-03-05 21:00:40 -0500 |
commit | 1e49a94cf707204b66a3fb242f2814712c941f52 (patch) | |
tree | f48473cc774abaeeafaa2e7fc1b3409e00c4a7d6 /fs/exfat/balloc.c | |
parent | 31023864e67a5f390cefbe92f72343027dc3aa33 (diff) |
exfat: add bitmap operations
This adds the implementation of bitmap operations for exfat.
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
Reviewed-by: Pali Rohár <pali.rohar@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/exfat/balloc.c')
-rw-r--r-- | fs/exfat/balloc.c | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/fs/exfat/balloc.c b/fs/exfat/balloc.c new file mode 100644 index 000000000000..6a04cc02565a --- /dev/null +++ b/fs/exfat/balloc.c @@ -0,0 +1,280 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd. + */ + +#include <linux/blkdev.h> +#include <linux/slab.h> +#include <linux/buffer_head.h> + +#include "exfat_raw.h" +#include "exfat_fs.h" + +static const unsigned char free_bit[] = { + 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2,/* 0 ~ 19*/ + 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 3,/* 20 ~ 39*/ + 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/* 40 ~ 59*/ + 0, 1, 0, 6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4,/* 60 ~ 79*/ + 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2,/* 80 ~ 99*/ + 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3,/*100 ~ 119*/ + 0, 1, 0, 2, 0, 1, 0, 7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/*120 ~ 139*/ + 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5,/*140 ~ 159*/ + 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2,/*160 ~ 179*/ + 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 6, 0, 1, 0, 2, 0, 1, 0, 3,/*180 ~ 199*/ + 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2,/*200 ~ 219*/ + 0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4,/*220 ~ 239*/ + 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0 /*240 ~ 254*/ +}; + +static const unsigned char used_bit[] = { + 0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, 1, 2, 2, 3,/* 0 ~ 19*/ + 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 1, 2, 2, 3, 2, 3, 3, 4,/* 20 ~ 39*/ + 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5,/* 40 ~ 59*/ + 4, 5, 5, 6, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,/* 60 ~ 79*/ + 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4,/* 80 ~ 99*/ + 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6,/*100 ~ 119*/ + 4, 5, 5, 6, 5, 6, 6, 7, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4,/*120 ~ 139*/ + 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,/*140 ~ 159*/ + 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5,/*160 ~ 179*/ + 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 2, 3, 3, 4, 3, 4, 4, 5,/*180 ~ 199*/ + 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6,/*200 ~ 219*/ + 5, 6, 6, 7, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,/*220 ~ 239*/ + 4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8 /*240 ~ 255*/ +}; + +/* + * Allocation Bitmap Management Functions + */ +static int exfat_allocate_bitmap(struct super_block *sb, + struct exfat_dentry *ep) +{ + struct exfat_sb_info *sbi = EXFAT_SB(sb); + long long map_size; + unsigned int i, need_map_size; + sector_t sector; + + sbi->map_clu = le32_to_cpu(ep->dentry.bitmap.start_clu); + map_size = le64_to_cpu(ep->dentry.bitmap.size); + need_map_size = ((EXFAT_DATA_CLUSTER_COUNT(sbi) - 1) / BITS_PER_BYTE) + + 1; + if (need_map_size != map_size) { + exfat_msg(sb, KERN_ERR, + "bogus allocation bitmap size(need : %u, cur : %lld)", + need_map_size, map_size); + /* + * Only allowed when bogus allocation + * bitmap size is large + */ + if (need_map_size > map_size) + return -EIO; + } + sbi->map_sectors = ((need_map_size - 1) >> + (sb->s_blocksize_bits)) + 1; + sbi->vol_amap = kmalloc_array(sbi->map_sectors, + sizeof(struct buffer_head *), GFP_KERNEL); + if (!sbi->vol_amap) + return -ENOMEM; + + sector = exfat_cluster_to_sector(sbi, sbi->map_clu); + for (i = 0; i < sbi->map_sectors; i++) { + sbi->vol_amap[i] = sb_bread(sb, sector + i); + if (!sbi->vol_amap[i]) { + /* release all buffers and free vol_amap */ + int j = 0; + + while (j < i) + brelse(sbi->vol_amap[j++]); + + kfree(sbi->vol_amap); + sbi->vol_amap = NULL; + return -EIO; + } + } + + sbi->pbr_bh = NULL; + return 0; +} + +int exfat_load_bitmap(struct super_block *sb) +{ + unsigned int i, type; + struct exfat_chain clu; + struct exfat_sb_info *sbi = EXFAT_SB(sb); + + exfat_chain_set(&clu, sbi->root_dir, 0, ALLOC_FAT_CHAIN); + while (clu.dir != EXFAT_EOF_CLUSTER) { + for (i = 0; i < sbi->dentries_per_clu; i++) { + struct exfat_dentry *ep; + struct buffer_head *bh; + + ep = exfat_get_dentry(sb, &clu, i, &bh, NULL); + if (!ep) + return -EIO; + + type = exfat_get_entry_type(ep); + if (type == TYPE_UNUSED) + break; + if (type != TYPE_BITMAP) + continue; + if (ep->dentry.bitmap.flags == 0x0) { + int err; + + err = exfat_allocate_bitmap(sb, ep); + brelse(bh); + return err; + } + brelse(bh); + } + + if (exfat_get_next_cluster(sb, &clu.dir)) + return -EIO; + } + + return -EINVAL; +} + +void exfat_free_bitmap(struct exfat_sb_info *sbi) +{ + int i; + + brelse(sbi->pbr_bh); + + for (i = 0; i < sbi->map_sectors; i++) + __brelse(sbi->vol_amap[i]); + + kfree(sbi->vol_amap); +} + +/* + * If the value of "clu" is 0, it means cluster 2 which is the first cluster of + * the cluster heap. + */ +int exfat_set_bitmap(struct inode *inode, unsigned int clu) +{ + int i, b; + unsigned int ent_idx; + struct super_block *sb = inode->i_sb; + struct exfat_sb_info *sbi = EXFAT_SB(sb); + + WARN_ON(clu < EXFAT_FIRST_CLUSTER); + ent_idx = CLUSTER_TO_BITMAP_ENT(clu); + i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx); + b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx); + + set_bit_le(b, sbi->vol_amap[i]->b_data); + exfat_update_bh(sb, sbi->vol_amap[i], IS_DIRSYNC(inode)); + return 0; +} + +/* + * If the value of "clu" is 0, it means cluster 2 which is the first cluster of + * the cluster heap. + */ +void exfat_clear_bitmap(struct inode *inode, unsigned int clu) +{ + int i, b; + unsigned int ent_idx; + struct super_block *sb = inode->i_sb; + struct exfat_sb_info *sbi = EXFAT_SB(sb); + struct exfat_mount_options *opts = &sbi->options; + + WARN_ON(clu < EXFAT_FIRST_CLUSTER); + ent_idx = CLUSTER_TO_BITMAP_ENT(clu); + i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx); + b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx); + + clear_bit_le(b, sbi->vol_amap[i]->b_data); + exfat_update_bh(sb, sbi->vol_amap[i], IS_DIRSYNC(inode)); + + if (opts->discard) { + int ret_discard; + + ret_discard = sb_issue_discard(sb, + exfat_cluster_to_sector(sbi, clu + + EXFAT_RESERVED_CLUSTERS), + (1 << sbi->sect_per_clus_bits), GFP_NOFS, 0); + + if (ret_discard == -EOPNOTSUPP) { + exfat_msg(sb, KERN_ERR, + "discard not supported by device, disabling"); + opts->discard = 0; + } + } +} + +/* + * If the value of "clu" is 0, it means cluster 2 which is the first cluster of + * the cluster heap. + */ +unsigned int exfat_find_free_bitmap(struct super_block *sb, unsigned int clu) +{ + unsigned int i, map_i, map_b, ent_idx; + unsigned int clu_base, clu_free; + unsigned char k, clu_mask; + struct exfat_sb_info *sbi = EXFAT_SB(sb); + + WARN_ON(clu < EXFAT_FIRST_CLUSTER); + ent_idx = CLUSTER_TO_BITMAP_ENT(clu); + clu_base = BITMAP_ENT_TO_CLUSTER(ent_idx & ~(BITS_PER_BYTE_MASK)); + clu_mask = IGNORED_BITS_REMAINED(clu, clu_base); + + map_i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx); + map_b = BITMAP_OFFSET_BYTE_IN_SECTOR(sb, ent_idx); + + for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; + i += BITS_PER_BYTE) { + k = *(sbi->vol_amap[map_i]->b_data + map_b); + if (clu_mask > 0) { + k |= clu_mask; + clu_mask = 0; + } + if (k < 0xFF) { + clu_free = clu_base + free_bit[k]; + if (clu_free < sbi->num_clusters) + return clu_free; + } + clu_base += BITS_PER_BYTE; + + if (++map_b >= sb->s_blocksize || + clu_base >= sbi->num_clusters) { + if (++map_i >= sbi->map_sectors) { + clu_base = EXFAT_FIRST_CLUSTER; + map_i = 0; + } + map_b = 0; + } + } + + return EXFAT_EOF_CLUSTER; +} + +int exfat_count_used_clusters(struct super_block *sb, unsigned int *ret_count) +{ + struct exfat_sb_info *sbi = EXFAT_SB(sb); + unsigned int count = 0; + unsigned int i, map_i = 0, map_b = 0; + unsigned int total_clus = EXFAT_DATA_CLUSTER_COUNT(sbi); + unsigned int last_mask = total_clus & BITS_PER_BYTE_MASK; + unsigned char clu_bits; + const unsigned char last_bit_mask[] = {0, 0b00000001, 0b00000011, + 0b00000111, 0b00001111, 0b00011111, 0b00111111, 0b01111111}; + + total_clus &= ~last_mask; + for (i = 0; i < total_clus; i += BITS_PER_BYTE) { + clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b); + count += used_bit[clu_bits]; + if (++map_b >= (unsigned int)sb->s_blocksize) { + map_i++; + map_b = 0; + } + } + + if (last_mask) { + clu_bits = *(sbi->vol_amap[map_i]->b_data + map_b); + clu_bits &= last_bit_mask[last_mask]; + count += used_bit[clu_bits]; + } + + *ret_count = count; + return 0; +} |