lkml.org 
[lkml]   [2019]   [Dec]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v6 06/13] exfat: add exfat entry operations
From
Date
On Mon, 2019-12-09 at 01:51 -0500, Namjae Jeon wrote:
> This adds the implementation of exfat entry operations for exfat.
>
> Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
> Signed-off-by: Sungjong Seo <sj1557.seo@samsung.com>
> ---
> fs/exfat/fatent.c | 472
> ++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 472 insertions(+)
> create mode 100644 fs/exfat/fatent.c
>
> diff --git a/fs/exfat/fatent.c b/fs/exfat/fatent.c
> new file mode 100644
> index 000000000000..0598aa2d04c1
> --- /dev/null
> +++ b/fs/exfat/fatent.c
> @@ -0,0 +1,472 @@
> +// 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 "exfat_raw.h"
> +#include "exfat_fs.h"
> +
> +static int __exfat_ent_get(struct super_block *sb, unsigned int loc,
> + unsigned int *content)
> +{
> + unsigned int off, _content;
> + sector_t sec;
> + struct exfat_sb_info *sbi = EXFAT_SB(sb);
> + struct buffer_head *bh;
> +
> + sec = sbi->FAT1_start_sector + (loc >> (sb->s_blocksize_bits-
> 2));
> + off = (loc << 2) & (sb->s_blocksize - 1);

It's slightly hard to follow why 2 is used here. Maybe, it makes sense
to rework the code here? I believe the constant could make this code
more easy to understand.

> +
> + 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 >= CLUSTER_32(0xFFFFFFF8))
> + _content = EOF_CLUSTER;
> +
> + *content = CLUSTER_32(_content);
> + 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 exfat_sb_info *sbi = EXFAT_SB(sb);
> + struct buffer_head *bh;
> +
> + sec = sbi->FAT1_start_sector + (loc >> (sb->s_blocksize_bits-
> 2));
> + off = (loc << 2) & (sb->s_blocksize - 1);

Ditto.

> +
> + 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_reserved_cluster(unsigned int clus)
> +{
> + if (clus == FREE_CLUSTER || clus == EOF_CLUSTER || clus ==
> BAD_CLUSTER)
> + return true;
> + return false;
> +}
> +
> +static inline bool is_valid_cluster(struct exfat_sb_info *sbi,
> + unsigned int clus)
> +{
> + if (clus < BASE_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 (!is_reserved_cluster(*content) &&
> + !is_valid_cluster(sbi, *content)) {
> + exfat_fs_error(sb,
> + "invalid access to FAT (entry 0x%08x) bogus
> content (0x%08x)",
> + loc, *content);
> + return -EIO;
> + }
> +
> + if (*content == FREE_CLUSTER) {
> + exfat_fs_error(sb,
> + "invalid access to FAT free cluster (entry
> 0x%08x)",
> + loc);
> + return -EIO;
> + }
> +
> + if (*content == BAD_CLUSTER) {
> + exfat_fs_error(sb,
> + "invalid access to FAT bad cluster (entry
> 0x%08x)",
> + loc);
> + 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, 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 == FREE_CLUSTER || p_chain->dir ==
> EOF_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-2);

What if clu could be lesser than 2? Any gurantee of this?

> + clu++;
> +
> + num_clusters++;
> + } while (num_clusters < p_chain->size);
> + } else {
> + do {
> + exfat_clear_bitmap(inode, (clu -
> BASE_CLUSTER));

Ditto.

> +
> + if (exfat_get_next_cluster(sb, &clu))
> + goto dec_used_clus;
> +
> + num_clusters++;
> + } while (clu != 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 != 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 = EOF_CLUSTER;
> + struct super_block *sb = inode->i_sb;
> + struct exfat_sb_info *sbi = EXFAT_SB(sb);
> +
> + total_cnt = sbi->num_clusters - BASE_CLUSTER;
> +
> + 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 == EOF_CLUSTER) {
> + if (sbi->clu_srch_ptr < BASE_CLUSTER) {
> + exfat_msg(sb, KERN_ERR,
> + "sbi->clu_srch_ptr is invalid (%u)\n",
> + sbi->clu_srch_ptr);
> + sbi->clu_srch_ptr = BASE_CLUSTER;
> + }
> +
> + hint_clu = exfat_test_bitmap(sb,
> + sbi->clu_srch_ptr - BASE_CLUSTER);
> + if (hint_clu == EOF_CLUSTER)
> + return -ENOSPC;
> + }
> +
> + /* check cluster validation */
> + if (hint_clu < BASE_CLUSTER && hint_clu >= sbi->num_clusters) {
> + exfat_msg(sb, KERN_ERR, "hint_cluster is invalid
> (%u)\n",
> + hint_clu);
> + hint_clu = BASE_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 = EOF_CLUSTER;
> +
> + while ((new_clu = exfat_test_bitmap(sb,
> + hint_clu - BASE_CLUSTER)) != 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 - BASE_CLUSTER)) {
> + ret = -EIO;
> + goto free_cluster;
> + }
> +
> + num_clusters++;
> +
> + /* update FAT table */
> + if (p_chain->flags == ALLOC_FAT_CHAIN) {
> + if (exfat_ent_set(sb, new_clu, EOF_CLUSTER)) {
> + ret = -EIO;
> + goto free_cluster;
> + }
> + }
> +
> + if (p_chain->dir == 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 = BASE_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 == 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 = BASE_CLUSTER; i < sbi->num_clusters; i++) {

Why does it start from BASE_CLUSTER? Maybe it makese sense to comment
this?

Thanks,
Viacheslav Dubeyko.

> + count++;
> + if (exfat_ent_get(sb, clu, &clu))
> + return -EIO;
> + if (clu == EOF_CLUSTER)
> + break;
> + }
> +
> + *ret_count = count;
> + return 0;
> +}
> +
> +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;
> +}

\
 
 \ /
  Last update: 2019-12-09 12:42    [W:0.133 / U:0.904 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site