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