exfat: handle unreconized benign secondary entries

Sony PXW-Z280 camera add vendor allocation entries to directory of
pictures. Currently, linux exfat does not support it and the file is
not visible. This patch handle vendor extension and allocation entries
as unreconized benign secondary entries. As described in the specification,
it is recognized but ignored, and when deleting directory entry set,
the associated clusters allocation are removed as well as benign secondary
directory entries.

Reported-by: Barócsi Dénes <admin@tveger.hu>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Reviewed-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

1 files changed, 58 insertions, 25 deletions

diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c
index 158427e8124e..957574180a5e 100644
--- a/fs/exfat/dir.c
+++ b/fs/exfat/dir.c
@@ -29,14 +29,15 @@ static int exfat_extract_uni_name(struct exfat_dentry *ep,
 
 }
 
-static void exfat_get_uniname_from_ext_entry(struct super_block *sb,
+static int exfat_get_uniname_from_ext_entry(struct super_block *sb,
 		struct exfat_chain *p_dir, int entry, unsigned short *uniname)
 {
-	int i;
+	int i, err;
 	struct exfat_entry_set_cache es;
 
-	if (exfat_get_dentry_set(&es, sb, p_dir, entry, ES_ALL_ENTRIES))
-		return;
+	err = exfat_get_dentry_set(&es, sb, p_dir, entry, ES_ALL_ENTRIES);
+	if (err)
+		return err;
 
 	/*
 	 * First entry  : file entry
@@ -56,12 +57,13 @@ static void exfat_get_uniname_from_ext_entry(struct super_block *sb,
 	}
 
 	exfat_put_dentry_set(&es, false);
+	return 0;
 }
 
 /* read a directory entry from the opened directory */
 static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_entry *dir_entry)
 {
-	int i, dentries_per_clu, num_ext;
+	int i, dentries_per_clu, num_ext, err;
 	unsigned int type, clu_offset, max_dentries;
 	struct exfat_chain dir, clu;
 	struct exfat_uni_name uni_name;
@@ -146,8 +148,12 @@ static int exfat_readdir(struct inode *inode, loff_t *cpos, struct exfat_dir_ent
 					0);
 
 			*uni_name.name = 0x0;
-			exfat_get_uniname_from_ext_entry(sb, &clu, i,
+			err = exfat_get_uniname_from_ext_entry(sb, &clu, i,
 				uni_name.name);
+			if (err) {
+				brelse(bh);
+				continue;
+			}
 			exfat_utf16_to_nls(sb, &uni_name,
 				dir_entry->namebuf.lfn,
 				dir_entry->namebuf.lfnbuf_len);
@@ -375,6 +381,12 @@ unsigned int exfat_get_entry_type(struct exfat_dentry *ep)
 			return TYPE_ACL;
 		return TYPE_CRITICAL_SEC;
 	}
+
+	if (ep->type == EXFAT_VENDOR_EXT)
+		return TYPE_VENDOR_EXT;
+	if (ep->type == EXFAT_VENDOR_ALLOC)
+		return TYPE_VENDOR_ALLOC;
+
 	return TYPE_BENIGN_SEC;
 }
 
@@ -518,6 +530,25 @@ release_fbh:
 	return ret;
 }
 
+static void exfat_free_benign_secondary_clusters(struct inode *inode,
+		struct exfat_dentry *ep)
+{
+	struct super_block *sb = inode->i_sb;
+	struct exfat_chain dir;
+	unsigned int start_clu =
+		le32_to_cpu(ep->dentry.generic_secondary.start_clu);
+	u64 size = le64_to_cpu(ep->dentry.generic_secondary.size);
+	unsigned char flags = ep->dentry.generic_secondary.flags;
+
+	if (!(flags & ALLOC_POSSIBLE) || !start_clu || !size)
+		return;
+
+	exfat_chain_set(&dir, start_clu,
+			EXFAT_B_TO_CLU_ROUND_UP(size, EXFAT_SB(sb)),
+			flags);
+	exfat_free_cluster(inode, &dir);
+}
+
 int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
 		int entry, int num_entries, struct exfat_uni_name *p_uniname)
 {
@@ -550,6 +581,9 @@ int exfat_init_ext_entry(struct inode *inode, struct exfat_chain *p_dir,
 		if (!ep)
 			return -EIO;
 
+		if (exfat_get_entry_type(ep) & TYPE_BENIGN_SEC)
+			exfat_free_benign_secondary_clusters(inode, ep);
+
 		exfat_init_name_entry(ep, uniname);
 		exfat_update_bh(bh, sync);
 		brelse(bh);
@@ -573,6 +607,9 @@ int exfat_remove_entries(struct inode *inode, struct exfat_chain *p_dir,
 		if (!ep)
 			return -EIO;
 
+		if (exfat_get_entry_type(ep) & TYPE_BENIGN_SEC)
+			exfat_free_benign_secondary_clusters(inode, ep);
+
 		exfat_set_entry_type(ep, TYPE_DELETED);
 		exfat_update_bh(bh, IS_DIRSYNC(inode));
 		brelse(bh);
@@ -741,6 +778,7 @@ enum exfat_validate_dentry_mode {
 	ES_MODE_GET_STRM_ENTRY,
 	ES_MODE_GET_NAME_ENTRY,
 	ES_MODE_GET_CRITICAL_SEC_ENTRY,
+	ES_MODE_GET_BENIGN_SEC_ENTRY,
 };
 
 static bool exfat_validate_entry(unsigned int type,
@@ -754,36 +792,33 @@ static bool exfat_validate_entry(unsigned int type,
 		if  (type != TYPE_FILE && type != TYPE_DIR)
 			return false;
 		*mode = ES_MODE_GET_FILE_ENTRY;
-		return true;
+		break;
 	case ES_MODE_GET_FILE_ENTRY:
 		if (type != TYPE_STREAM)
 			return false;
 		*mode = ES_MODE_GET_STRM_ENTRY;
-		return true;
+		break;
 	case ES_MODE_GET_STRM_ENTRY:
 		if (type != TYPE_EXTEND)
 			return false;
 		*mode = ES_MODE_GET_NAME_ENTRY;
-		return true;
+		break;
 	case ES_MODE_GET_NAME_ENTRY:
-		if (type == TYPE_STREAM)
+		if (type & TYPE_BENIGN_SEC)
+			*mode = ES_MODE_GET_BENIGN_SEC_ENTRY;
+		else if (type != TYPE_EXTEND)
 			return false;
-		if (type != TYPE_EXTEND) {
-			if (!(type & TYPE_CRITICAL_SEC))
-				return false;
-			*mode = ES_MODE_GET_CRITICAL_SEC_ENTRY;
-		}
-		return true;
-	case ES_MODE_GET_CRITICAL_SEC_ENTRY:
-		if (type == TYPE_EXTEND || type == TYPE_STREAM)
-			return false;
-		if ((type & TYPE_CRITICAL_SEC) != TYPE_CRITICAL_SEC)
+		break;
+	case ES_MODE_GET_BENIGN_SEC_ENTRY:
+		/* Assume unreconized benign secondary entry */
+		if (!(type & TYPE_BENIGN_SEC))
 			return false;
-		return true;
+		break;
 	default:
-		WARN_ON_ONCE(1);
 		return false;
 	}
+
+	return true;
 }
 
 struct exfat_dentry *exfat_get_dentry_cached(
@@ -1164,10 +1199,8 @@ int exfat_count_ext_entries(struct super_block *sb, struct exfat_chain *p_dir,
 
 		type = exfat_get_entry_type(ext_ep);
 		brelse(bh);
-		if (type == TYPE_EXTEND || type == TYPE_STREAM)
+		if (type & TYPE_CRITICAL_SEC || type & TYPE_BENIGN_SEC)
 			count++;
-		else
-			break;
 	}
 	return count;
 }