diff options
Diffstat (limited to '')
| -rw-r--r-- | fs/exfat/fatent.c | 452 |
1 files changed, 452 insertions, 0 deletions
diff --git a/fs/exfat/fatent.c b/fs/exfat/fatent.c new file mode 100644 index 0000000000..56b870d9cc --- /dev/null +++ b/fs/exfat/fatent.c @@ -0,0 +1,452 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd. + */ + +#include <linux/slab.h> +#include <asm/unaligned.h> +#include <linux/buffer_head.h> +#include <linux/blkdev.h> + +#include "exfat_raw.h" +#include "exfat_fs.h" + +static int exfat_mirror_bh(struct super_block *sb, sector_t sec, + struct buffer_head *bh) +{ + struct buffer_head *c_bh; + struct exfat_sb_info *sbi = EXFAT_SB(sb); + sector_t sec2; + int err = 0; + + if (sbi->FAT2_start_sector != sbi->FAT1_start_sector) { + sec2 = sec - sbi->FAT1_start_sector + sbi->FAT2_start_sector; + c_bh = sb_getblk(sb, sec2); + if (!c_bh) + return -ENOMEM; + memcpy(c_bh->b_data, bh->b_data, sb->s_blocksize); + set_buffer_uptodate(c_bh); + mark_buffer_dirty(c_bh); + if (sb->s_flags & SB_SYNCHRONOUS) + err = sync_dirty_buffer(c_bh); + brelse(c_bh); + } + + return err; +} + +static int __exfat_ent_get(struct super_block *sb, unsigned int loc, + unsigned int *content) +{ + unsigned int off; + sector_t sec; + struct buffer_head *bh; + + sec = FAT_ENT_OFFSET_SECTOR(sb, loc); + off = FAT_ENT_OFFSET_BYTE_IN_SECTOR(sb, loc); + + bh = sb_bread(sb, sec); + if (!bh) + return -EIO; + + *content = le32_to_cpu(*(__le32 *)(&bh->b_data[off])); + + /* remap reserved clusters to simplify code */ + if (*content > EXFAT_BAD_CLUSTER) + *content = EXFAT_EOF_CLUSTER; + + brelse(bh); + return 0; +} + +int exfat_ent_set(struct super_block *sb, unsigned int loc, + unsigned int content) +{ + unsigned int off; + sector_t sec; + __le32 *fat_entry; + struct buffer_head *bh; + + sec = FAT_ENT_OFFSET_SECTOR(sb, loc); + off = FAT_ENT_OFFSET_BYTE_IN_SECTOR(sb, loc); + + bh = sb_bread(sb, sec); + if (!bh) + return -EIO; + + fat_entry = (__le32 *)&(bh->b_data[off]); + *fat_entry = cpu_to_le32(content); + exfat_update_bh(bh, sb->s_flags & SB_SYNCHRONOUS); + exfat_mirror_bh(sb, sec, bh); + brelse(bh); + return 0; +} + +int exfat_ent_get(struct super_block *sb, unsigned int loc, + unsigned int *content) +{ + struct exfat_sb_info *sbi = EXFAT_SB(sb); + int err; + + if (!is_valid_cluster(sbi, loc)) { + exfat_fs_error(sb, "invalid access to FAT (entry 0x%08x)", + loc); + return -EIO; + } + + err = __exfat_ent_get(sb, loc, content); + if (err) { + exfat_fs_error(sb, + "failed to access to FAT (entry 0x%08x, err:%d)", + loc, err); + return err; + } + + if (*content == EXFAT_FREE_CLUSTER) { + exfat_fs_error(sb, + "invalid access to FAT free cluster (entry 0x%08x)", + loc); + return -EIO; + } + + if (*content == EXFAT_BAD_CLUSTER) { + exfat_fs_error(sb, + "invalid access to FAT bad cluster (entry 0x%08x)", + loc); + return -EIO; + } + + if (*content != EXFAT_EOF_CLUSTER && !is_valid_cluster(sbi, *content)) { + exfat_fs_error(sb, + "invalid access to FAT (entry 0x%08x) bogus content (0x%08x)", + loc, *content); + return -EIO; + } + + return 0; +} + +int exfat_chain_cont_cluster(struct super_block *sb, unsigned int chain, + unsigned int len) +{ + if (!len) + return 0; + + while (len > 1) { + if (exfat_ent_set(sb, chain, chain + 1)) + return -EIO; + chain++; + len--; + } + + if (exfat_ent_set(sb, chain, EXFAT_EOF_CLUSTER)) + return -EIO; + return 0; +} + +/* This function must be called with bitmap_lock held */ +static int __exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain) +{ + struct super_block *sb = inode->i_sb; + struct exfat_sb_info *sbi = EXFAT_SB(sb); + int cur_cmap_i, next_cmap_i; + unsigned int num_clusters = 0; + unsigned int clu; + + /* invalid cluster number */ + if (p_chain->dir == EXFAT_FREE_CLUSTER || + p_chain->dir == EXFAT_EOF_CLUSTER || + p_chain->dir < EXFAT_FIRST_CLUSTER) + return 0; + + /* no cluster to truncate */ + if (p_chain->size == 0) + return 0; + + /* check cluster validation */ + if (!is_valid_cluster(sbi, p_chain->dir)) { + exfat_err(sb, "invalid start cluster (%u)", p_chain->dir); + return -EIO; + } + + clu = p_chain->dir; + + cur_cmap_i = next_cmap_i = + BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(clu)); + + if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { + unsigned int last_cluster = p_chain->dir + p_chain->size - 1; + do { + bool sync = false; + + if (clu < last_cluster) + next_cmap_i = + BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(clu+1)); + + /* flush bitmap only if index would be changed or for last cluster */ + if (clu == last_cluster || cur_cmap_i != next_cmap_i) { + sync = true; + cur_cmap_i = next_cmap_i; + } + + exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode))); + clu++; + num_clusters++; + } while (num_clusters < p_chain->size); + } else { + do { + bool sync = false; + unsigned int n_clu = clu; + int err = exfat_get_next_cluster(sb, &n_clu); + + if (err || n_clu == EXFAT_EOF_CLUSTER) + sync = true; + else + next_cmap_i = + BITMAP_OFFSET_SECTOR_INDEX(sb, CLUSTER_TO_BITMAP_ENT(n_clu)); + + if (cur_cmap_i != next_cmap_i) { + sync = true; + cur_cmap_i = next_cmap_i; + } + + exfat_clear_bitmap(inode, clu, (sync && IS_DIRSYNC(inode))); + clu = n_clu; + num_clusters++; + + if (err) + goto dec_used_clus; + } while (clu != EXFAT_EOF_CLUSTER); + } + +dec_used_clus: + sbi->used_clusters -= num_clusters; + return 0; +} + +int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain) +{ + int ret = 0; + + mutex_lock(&EXFAT_SB(inode->i_sb)->bitmap_lock); + ret = __exfat_free_cluster(inode, p_chain); + mutex_unlock(&EXFAT_SB(inode->i_sb)->bitmap_lock); + + return ret; +} + +int exfat_find_last_cluster(struct super_block *sb, struct exfat_chain *p_chain, + unsigned int *ret_clu) +{ + unsigned int clu, next; + unsigned int count = 0; + + next = p_chain->dir; + if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { + *ret_clu = next + p_chain->size - 1; + return 0; + } + + do { + count++; + clu = next; + if (exfat_ent_get(sb, clu, &next)) + return -EIO; + } while (next != EXFAT_EOF_CLUSTER); + + if (p_chain->size != count) { + exfat_fs_error(sb, + "bogus directory size (clus : ondisk(%d) != counted(%d))", + p_chain->size, count); + return -EIO; + } + + *ret_clu = clu; + return 0; +} + +int exfat_zeroed_cluster(struct inode *dir, unsigned int clu) +{ + struct super_block *sb = dir->i_sb; + struct exfat_sb_info *sbi = EXFAT_SB(sb); + struct buffer_head *bh; + sector_t blknr, last_blknr, i; + + blknr = exfat_cluster_to_sector(sbi, clu); + last_blknr = blknr + sbi->sect_per_clus; + + if (last_blknr > sbi->num_sectors && sbi->num_sectors > 0) { + exfat_fs_error_ratelimit(sb, + "%s: out of range(sect:%llu len:%u)", + __func__, (unsigned long long)blknr, + sbi->sect_per_clus); + return -EIO; + } + + /* Zeroing the unused blocks on this cluster */ + for (i = blknr; i < last_blknr; i++) { + bh = sb_getblk(sb, i); + if (!bh) + return -ENOMEM; + + memset(bh->b_data, 0, sb->s_blocksize); + set_buffer_uptodate(bh); + mark_buffer_dirty(bh); + brelse(bh); + } + + if (IS_DIRSYNC(dir)) + return sync_blockdev_range(sb->s_bdev, + EXFAT_BLK_TO_B(blknr, sb), + EXFAT_BLK_TO_B(last_blknr, sb) - 1); + + return 0; +} + +int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc, + struct exfat_chain *p_chain, bool sync_bmap) +{ + int ret = -ENOSPC; + unsigned int total_cnt; + unsigned int hint_clu, new_clu, last_clu = EXFAT_EOF_CLUSTER; + struct super_block *sb = inode->i_sb; + struct exfat_sb_info *sbi = EXFAT_SB(sb); + + total_cnt = EXFAT_DATA_CLUSTER_COUNT(sbi); + + if (unlikely(total_cnt < sbi->used_clusters)) { + exfat_fs_error_ratelimit(sb, + "%s: invalid used clusters(t:%u,u:%u)\n", + __func__, total_cnt, sbi->used_clusters); + return -EIO; + } + + if (num_alloc > total_cnt - sbi->used_clusters) + return -ENOSPC; + + mutex_lock(&sbi->bitmap_lock); + + hint_clu = p_chain->dir; + /* find new cluster */ + if (hint_clu == EXFAT_EOF_CLUSTER) { + if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) { + exfat_err(sb, "sbi->clu_srch_ptr is invalid (%u)", + sbi->clu_srch_ptr); + sbi->clu_srch_ptr = EXFAT_FIRST_CLUSTER; + } + + hint_clu = exfat_find_free_bitmap(sb, sbi->clu_srch_ptr); + if (hint_clu == EXFAT_EOF_CLUSTER) { + ret = -ENOSPC; + goto unlock; + } + } + + /* check cluster validation */ + if (!is_valid_cluster(sbi, hint_clu)) { + if (hint_clu != sbi->num_clusters) + exfat_err(sb, "hint_cluster is invalid (%u), rewind to the first cluster", + hint_clu); + hint_clu = EXFAT_FIRST_CLUSTER; + p_chain->flags = ALLOC_FAT_CHAIN; + } + + p_chain->dir = EXFAT_EOF_CLUSTER; + + while ((new_clu = exfat_find_free_bitmap(sb, hint_clu)) != + EXFAT_EOF_CLUSTER) { + if (new_clu != hint_clu && + p_chain->flags == ALLOC_NO_FAT_CHAIN) { + if (exfat_chain_cont_cluster(sb, p_chain->dir, + p_chain->size)) { + ret = -EIO; + goto free_cluster; + } + p_chain->flags = ALLOC_FAT_CHAIN; + } + + /* update allocation bitmap */ + if (exfat_set_bitmap(inode, new_clu, sync_bmap)) { + ret = -EIO; + goto free_cluster; + } + + /* update FAT table */ + if (p_chain->flags == ALLOC_FAT_CHAIN) { + if (exfat_ent_set(sb, new_clu, EXFAT_EOF_CLUSTER)) { + ret = -EIO; + goto free_cluster; + } + } + + if (p_chain->dir == EXFAT_EOF_CLUSTER) { + p_chain->dir = new_clu; + } else if (p_chain->flags == ALLOC_FAT_CHAIN) { + if (exfat_ent_set(sb, last_clu, new_clu)) { + ret = -EIO; + goto free_cluster; + } + } + p_chain->size++; + + last_clu = new_clu; + + if (p_chain->size == num_alloc) { + sbi->clu_srch_ptr = hint_clu; + sbi->used_clusters += num_alloc; + + mutex_unlock(&sbi->bitmap_lock); + return 0; + } + + hint_clu = new_clu + 1; + if (hint_clu >= sbi->num_clusters) { + hint_clu = EXFAT_FIRST_CLUSTER; + + if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { + if (exfat_chain_cont_cluster(sb, p_chain->dir, + p_chain->size)) { + ret = -EIO; + goto free_cluster; + } + p_chain->flags = ALLOC_FAT_CHAIN; + } + } + } +free_cluster: + __exfat_free_cluster(inode, p_chain); +unlock: + mutex_unlock(&sbi->bitmap_lock); + return ret; +} + +int exfat_count_num_clusters(struct super_block *sb, + struct exfat_chain *p_chain, unsigned int *ret_count) +{ + unsigned int i, count; + unsigned int clu; + struct exfat_sb_info *sbi = EXFAT_SB(sb); + + if (!p_chain->dir || p_chain->dir == EXFAT_EOF_CLUSTER) { + *ret_count = 0; + return 0; + } + + if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { + *ret_count = p_chain->size; + return 0; + } + + clu = p_chain->dir; + count = 0; + for (i = EXFAT_FIRST_CLUSTER; i < sbi->num_clusters; i++) { + count++; + if (exfat_ent_get(sb, clu, &clu)) + return -EIO; + if (clu == EXFAT_EOF_CLUSTER) + break; + } + + *ret_count = count; + return 0; +} |