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exfat: support handle zero-size directory

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After repairing a corrupted file system with exfatprogs' fsck.exfat,
zero-size directories may result. It is also possible to create
zero-size directories in other exFAT implementation, such as Paragon
ufsd dirver.

As described in the specification, the lower directory size limits
is 0 bytes.

Without this commit, sub-directories and files cannot be created
under a zero-size directory, and it cannot be removed.

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
This commit is contained in:
Yuezhang Mo 2023-09-04 11:08:43 +09:00 committed by Namjae Jeon
parent cc9879a6ce
commit f6c705d1d9
1 changed files with 22 additions and 7 deletions
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29
namei.c
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@ -378,14 +378,20 @@ static int exfat_find_empty_entry(struct inode *inode,
if (exfat_check_max_dentries(inode))
return -ENOSPC;
/* we trust p_dir->size regardless of FAT type */
if (exfat_find_last_cluster(sb, p_dir, &last_clu))
return -EIO;
/*
* Allocate new cluster to this directory
*/
exfat_chain_set(&clu, last_clu + 1, 0, p_dir->flags);
if (ei->start_clu != EXFAT_EOF_CLUSTER) {
/* we trust p_dir->size regardless of FAT type */
if (exfat_find_last_cluster(sb, p_dir, &last_clu))
return -EIO;
exfat_chain_set(&clu, last_clu + 1, 0, p_dir->flags);
} else {
/* This directory is empty */
exfat_chain_set(&clu, EXFAT_EOF_CLUSTER, 0,
ALLOC_NO_FAT_CHAIN);
}
/* allocate a cluster */
ret = exfat_alloc_cluster(inode, 1, &clu, IS_DIRSYNC(inode));
@ -395,6 +401,11 @@ static int exfat_find_empty_entry(struct inode *inode,
if (exfat_zeroed_cluster(inode, clu.dir))
return -EIO;
if (ei->start_clu == EXFAT_EOF_CLUSTER) {
ei->start_clu = clu.dir;
p_dir->dir = clu.dir;
}
/* append to the FAT chain */
if (clu.flags != p_dir->flags) {
/* no-fat-chain bit is disabled,
@ -709,7 +720,7 @@ static int exfat_find(struct inode *dir, struct qstr *qname,
info->type = exfat_get_entry_type(ep);
info->attr = le16_to_cpu(ep->dentry.file.attr);
info->size = le64_to_cpu(ep2->dentry.stream.valid_size);
if ((info->type == TYPE_FILE) && (info->size == 0)) {
if (info->size == 0) {
info->flags = ALLOC_NO_FAT_CHAIN;
info->start_clu = EXFAT_EOF_CLUSTER;
} else {
@ -1000,6 +1011,9 @@ static int exfat_check_dir_empty(struct super_block *sb,
dentries_per_clu = sbi->dentries_per_clu;
if (p_dir->dir == EXFAT_EOF_CLUSTER)
return 0;
exfat_chain_dup(&clu, p_dir);
while (clu.dir != EXFAT_EOF_CLUSTER) {
@ -1383,7 +1397,8 @@ static int __exfat_rename(struct inode *old_parent_inode,
}
/* Free the clusters if new_inode is a dir(as if exfat_rmdir) */
if (new_entry_type == TYPE_DIR) {
if (new_entry_type == TYPE_DIR &&
new_ei->start_clu != EXFAT_EOF_CLUSTER) {
/* new_ei, new_clu_to_free */
struct exfat_chain new_clu_to_free;