[PATCH v3 6/6] exfat: use exfat_chain_advance helper

Chi Zhiling
2026-04-03T08:06:57Z

Replace open-coded cluster chain walking logic with exfat_chain_advance()
across exfat_readdir, exfat_find_dir_entry, exfat_count_dir_entries,
exfat_search_empty_slot and exfat_check_dir_empty.

Signed-off-by: Chi Zhiling <chizhiling@kylinos.cn>
---
fs/exfat/dir.c | 71 ++++++++++++------------------------------------
fs/exfat/namei.c | 28 +++++--------------
2 files changed, 25 insertions(+), 74 deletions(-)

diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c
index ca5827046a1f..ac008ccaa97d 100644
--- a/fs/exfat/dir.c
+++ b/fs/exfat/dir.c
@@ -93,25 +93,19 @@ static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_ent
clu_offset = EXFAT_DEN_TO_CLU(dentry, sbi);
exfat_chain_dup(&clu, &dir);

- if (clu.flags == ALLOC_NO_FAT_CHAIN) {
- clu.dir += clu_offset;
- clu.size -= clu_offset;
- } else {
+ if (clu.flags == ALLOC_FAT_CHAIN) {
/* hint_information */
if (clu_offset > 0 && ei->hint_bmap.off != EXFAT_EOF_CLUSTER &&
ei->hint_bmap.off > 0 && clu_offset >= ei->hint_bmap.off) {
clu_offset -= ei->hint_bmap.off;
clu.dir = ei->hint_bmap.clu;
- }
-
- while (clu_offset > 0 && clu.dir != EXFAT_EOF_CLUSTER) {
- if (exfat_get_next_cluster(sb, &(clu.dir)))
- return -EIO;
-
- clu_offset--;
+ clu.size -= ei->hint_bmap.off;
}
}

+ if (exfat_chain_advance(sb, &clu, clu_offset))
+ return -EIO;
+
while (clu.dir != EXFAT_EOF_CLUSTER && dentry < max_dentries) {
i = dentry & (dentries_per_clu - 1);

@@ -160,15 +154,8 @@ static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_ent
return 0;
}

- if (clu.flags == ALLOC_NO_FAT_CHAIN) {
- if (--clu.size > 0)
- clu.dir++;
- else
- clu.dir = EXFAT_EOF_CLUSTER;
- } else {
- if (exfat_get_next_cluster(sb, &(clu.dir)))
- return -EIO;
- }
+ if (exfat_chain_advance(sb, &clu, 1))
+ return -EIO;
}

out:
@@ -1085,19 +1072,12 @@ int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
step = DIRENT_STEP_FILE;
}

- if (clu.flags == ALLOC_NO_FAT_CHAIN) {
- if (--clu.size > 0)
- clu.dir++;
- else
- clu.dir = EXFAT_EOF_CLUSTER;
- } else {
- if (exfat_get_next_cluster(sb, &clu.dir))
- return -EIO;
+ if (exfat_chain_advance(sb, &clu, 1))
+ return -EIO;

- /* break if the cluster chain includes a loop */
- if (unlikely(++clu_count > EXFAT_DATA_CLUSTER_COUNT(sbi)))
- goto not_found;
- }
+ /* break if the cluster chain includes a loop */
+ if (unlikely(++clu_count > EXFAT_DATA_CLUSTER_COUNT(sbi)))
+ goto not_found;
}

not_found:
@@ -1132,14 +1112,7 @@ int exfat_find_dir_entry(struct super_block *sb, struct exfat_inode_info *ei,
if (!((dentry + 1) & (dentries_per_clu - 1))) {
int ret = 0;

- if (clu.flags == ALLOC_NO_FAT_CHAIN) {
- if (--clu.size > 0)
- clu.dir++;
- else
- clu.dir = EXFAT_EOF_CLUSTER;
- } else {
- ret = exfat_get_next_cluster(sb, &clu.dir);
- }
+ ret = exfat_chain_advance(sb, &clu, 1);

if (ret || clu.dir == EXFAT_EOF_CLUSTER) {
/* just initialized hint_stat */
@@ -1184,20 +1157,12 @@ int exfat_count_dir_entries(struct super_block *sb, struct exfat_chain *p_dir)
count++;
}

- if (clu.flags == ALLOC_NO_FAT_CHAIN) {
- if (--clu.size > 0)
- clu.dir++;
- else
- clu.dir = EXFAT_EOF_CLUSTER;
- } else {
- if (exfat_get_next_cluster(sb, &(clu.dir)))
- return -EIO;
-
- if (unlikely(++clu_count > sbi->used_clusters)) {
- exfat_fs_error(sb, "FAT or bitmap is corrupted");
- return -EIO;
- }
+ if (exfat_chain_advance(sb, &clu, 1))
+ return -EIO;

+ if (unlikely(++clu_count > sbi->used_clusters)) {
+ exfat_fs_error(sb, "FAT or bitmap is corrupted");
+ return -EIO;
}
}

diff --git a/fs/exfat/namei.c b/fs/exfat/namei.c
index d0ea1ff81c09..2c5636634b4a 100644
--- a/fs/exfat/namei.c
+++ b/fs/exfat/namei.c
@@ -246,15 +246,8 @@ static int exfat_search_empty_slot(struct super_block *sb,
i += ret;

while (i >= dentries_per_clu) {
- if (clu.flags == ALLOC_NO_FAT_CHAIN) {
- if (--clu.size > 0)
- clu.dir++;
- else
- clu.dir = EXFAT_EOF_CLUSTER;
- } else {
- if (exfat_get_next_cluster(sb, &clu.dir))
- return -EIO;
- }
+ if (exfat_chain_advance(sb, &clu, 1))
+ return -EIO;

i -= dentries_per_clu;
}
@@ -925,19 +918,12 @@ static int exfat_check_dir_empty(struct super_block *sb,
return -ENOTEMPTY;
}

- if (clu.flags == ALLOC_NO_FAT_CHAIN) {
- if (--clu.size > 0)
- clu.dir++;
- else
- clu.dir = EXFAT_EOF_CLUSTER;
- } else {
- if (exfat_get_next_cluster(sb, &(clu.dir)))
- return -EIO;
+ if (exfat_chain_advance(sb, &clu, 1))
+ return -EIO;

- /* break if the cluster chain includes a loop */
- if (unlikely(++clu_count > EXFAT_DATA_CLUSTER_COUNT(sbi)))
- break;
- }
+ /* break if the cluster chain includes a loop */
+ if (unlikely(++clu_count > EXFAT_DATA_CLUSTER_COUNT(sbi)))
+ break;
}

return 0;
--
2.43.0