From 31023864e67a5f390cefbe92f72343027dc3aa33 Mon Sep 17 00:00:00 2001 From: Namjae Jeon Date: Mon, 2 Mar 2020 15:21:37 +0900 Subject: exfat: add fat entry operations MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This adds the implementation of fat entry operations for exfat. Signed-off-by: Namjae Jeon Signed-off-by: Sungjong Seo Reviewed-by: Pali Rohár Reviewed-by: Christoph Hellwig Signed-off-by: Al Viro --- fs/exfat/fatent.c | 463 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 463 insertions(+) create mode 100644 fs/exfat/fatent.c (limited to 'fs/exfat') diff --git a/fs/exfat/fatent.c b/fs/exfat/fatent.c new file mode 100644 index 000000000000..a855b1769a96 --- /dev/null +++ b/fs/exfat/fatent.c @@ -0,0 +1,463 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright (C) 2012-2013 Samsung Electronics Co., Ltd. + */ + +#include +#include +#include + +#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(sb, bh, sb->s_flags & SB_SYNCHRONOUS); + exfat_mirror_bh(sb, sec, bh); + brelse(bh); + return 0; +} + +static inline bool is_valid_cluster(struct exfat_sb_info *sbi, + unsigned int clus) +{ + if (clus < EXFAT_FIRST_CLUSTER || sbi->num_clusters <= clus) + return false; + return true; +} + +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; +} + +int exfat_free_cluster(struct inode *inode, struct exfat_chain *p_chain) +{ + unsigned int num_clusters = 0; + unsigned int clu; + struct super_block *sb = inode->i_sb; + struct exfat_sb_info *sbi = EXFAT_SB(sb); + + /* 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 (p_chain->dir < 2 && p_chain->dir >= sbi->num_clusters) { + exfat_msg(sb, KERN_ERR, "invalid start cluster (%u)", + p_chain->dir); + return -EIO; + } + + set_bit(EXFAT_SB_DIRTY, &sbi->s_state); + clu = p_chain->dir; + + if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { + do { + exfat_clear_bitmap(inode, clu); + clu++; + + num_clusters++; + } while (num_clusters < p_chain->size); + } else { + do { + exfat_clear_bitmap(inode, clu); + + if (exfat_get_next_cluster(sb, &clu)) + goto dec_used_clus; + + num_clusters++; + } while (clu != EXFAT_EOF_CLUSTER); + } + +dec_used_clus: + sbi->used_clusters -= num_clusters; + return 0; +} + +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; +} + +static inline int exfat_sync_bhs(struct buffer_head **bhs, int nr_bhs) +{ + int i, err = 0; + + for (i = 0; i < nr_bhs; i++) + write_dirty_buffer(bhs[i], 0); + + for (i = 0; i < nr_bhs; i++) { + wait_on_buffer(bhs[i]); + if (!err && !buffer_uptodate(bhs[i])) + err = -EIO; + } + return err; +} + +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 *bhs[MAX_BUF_PER_PAGE]; + int nr_bhs = MAX_BUF_PER_PAGE; + sector_t blknr, last_blknr; + int err, i, n; + + 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 */ + n = 0; + while (blknr < last_blknr) { + bhs[n] = sb_getblk(sb, blknr); + if (!bhs[n]) { + err = -ENOMEM; + goto release_bhs; + } + memset(bhs[n]->b_data, 0, sb->s_blocksize); + exfat_update_bh(sb, bhs[n], 0); + + n++; + blknr++; + + if (n == nr_bhs) { + if (IS_DIRSYNC(dir)) { + err = exfat_sync_bhs(bhs, n); + if (err) + goto release_bhs; + } + + for (i = 0; i < n; i++) + brelse(bhs[i]); + n = 0; + } + } + + if (IS_DIRSYNC(dir)) { + err = exfat_sync_bhs(bhs, n); + if (err) + goto release_bhs; + } + + for (i = 0; i < n; i++) + brelse(bhs[i]); + + return 0; + +release_bhs: + exfat_msg(sb, KERN_ERR, "failed zeroed sect %llu\n", + (unsigned long long)blknr); + for (i = 0; i < n; i++) + bforget(bhs[i]); + return err; +} + +int exfat_alloc_cluster(struct inode *inode, unsigned int num_alloc, + struct exfat_chain *p_chain) +{ + int ret = -ENOSPC; + unsigned int num_clusters = 0, 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; + + hint_clu = p_chain->dir; + /* find new cluster */ + if (hint_clu == EXFAT_EOF_CLUSTER) { + if (sbi->clu_srch_ptr < EXFAT_FIRST_CLUSTER) { + exfat_msg(sb, KERN_ERR, + "sbi->clu_srch_ptr is invalid (%u)\n", + 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) + return -ENOSPC; + } + + /* check cluster validation */ + if (hint_clu < EXFAT_FIRST_CLUSTER && hint_clu >= sbi->num_clusters) { + exfat_msg(sb, KERN_ERR, "hint_cluster is invalid (%u)\n", + hint_clu); + hint_clu = EXFAT_FIRST_CLUSTER; + if (p_chain->flags == ALLOC_NO_FAT_CHAIN) { + if (exfat_chain_cont_cluster(sb, p_chain->dir, + num_clusters)) + return -EIO; + p_chain->flags = ALLOC_FAT_CHAIN; + } + } + + set_bit(EXFAT_SB_DIRTY, &sbi->s_state); + + 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, + num_clusters)) { + ret = -EIO; + goto free_cluster; + } + p_chain->flags = ALLOC_FAT_CHAIN; + } + + /* update allocation bitmap */ + if (exfat_set_bitmap(inode, new_clu)) { + ret = -EIO; + goto free_cluster; + } + + num_clusters++; + + /* 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; + } + } + last_clu = new_clu; + + if (--num_alloc == 0) { + sbi->clu_srch_ptr = hint_clu; + sbi->used_clusters += num_clusters; + + p_chain->size += num_clusters; + 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, + num_clusters)) { + ret = -EIO; + goto free_cluster; + } + p_chain->flags = ALLOC_FAT_CHAIN; + } + } + } +free_cluster: + if (num_clusters) + exfat_free_cluster(inode, p_chain); + 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; +} -- cgit v1.2.3