Commit dab48b8f authored by Yuezhang Mo's avatar Yuezhang Mo Committed by Namjae Jeon
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exfat: support handle zero-size directory 



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: default avatarYuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: default avatarAndy Wu <Andy.Wu@sony.com>
Reviewed-by: default avatarAoyama Wataru <wataru.aoyama@sony.com>
Signed-off-by: default avatarNamjae Jeon <linkinjeon@kernel.org>
parent 0ab8ba71

fs/exfat/namei.c

+22 −7
Original line number Diff line number Diff line
@@ -351,14 +351,20 @@ static int exfat_find_empty_entry(struct inode *inode, 
		if (exfat_check_max_dentries(inode))

			return -ENOSPC;



		/*

		 * Allocate new cluster to this directory

		 */

		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;



		/*

		 * Allocate new cluster to this directory

		 */

			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));
@@ -368,6 +374,11 @@ 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,
@@ -646,7 +657,7 @@ 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 {
@@ -889,6 +900,9 @@ 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) {
@@ -1256,7 +1270,8 @@ 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;