udf: Get rid of 0-length arrays in struct fileIdentDesc

Get rid of 0-length arrays in struct fileIdentDesc. This requires a bit
of cleaning up as the second variable length array in this structure is
often used and the code abuses the fact that the first two arrays have
the same type and offset in struct fileIdentDesc.
Signed-off-by: Jan Kara <jack@suse.cz>

fs/udf/dir.c

@@ -35,7 +35,6 @@
 #include "udf_i.h"
 #include "udf_sb.h"
 
-
 static int udf_readdir(struct file *file, struct dir_context *ctx)
 {
 	struct inode *dir = file_inode(file);
@@ -135,7 +134,7 @@ static int udf_readdir(struct file *file, struct dir_context *ctx)
 		lfi = cfi.lengthFileIdent;
 
 		if (fibh.sbh == fibh.ebh) {
-			nameptr = fi->fileIdent + liu;
+			nameptr = udf_get_fi_ident(fi);
 		} else {
 			int poffset;	/* Unpaded ending offset */
 
@@ -153,7 +152,7 @@ static int udf_readdir(struct file *file, struct dir_context *ctx)
 					}
 				}
 				nameptr = copy_name;
-				memcpy(nameptr, fi->fileIdent + liu,
+				memcpy(nameptr, udf_get_fi_ident(fi),
 				       lfi - poffset);
 				memcpy(nameptr + lfi - poffset,
 				       fibh.ebh->b_data, poffset);

fs/udf/ecma_167.h

@@ -471,9 +471,9 @@ struct fileIdentDesc {
 	uint8_t		lengthFileIdent;
 	struct long_ad	icb;
 	__le16		lengthOfImpUse;
-	uint8_t		impUse[0];
-	uint8_t		fileIdent[0];
-	uint8_t		padding[0];
+	uint8_t		impUse[];
+	/* uint8_t	fileIdent[]; */
+	/* uint8_t	padding[]; */
 } __packed;
 
 /* File Characteristics (ECMA 167r3 4/14.4.3) */

fs/udf/inode.c

@@ -390,8 +390,7 @@ struct buffer_head *udf_expand_dir_adinicb(struct inode *inode,
 		dfibh.eoffset += (sfibh.eoffset - sfibh.soffset);
 		dfi = (struct fileIdentDesc *)(dbh->b_data + dfibh.soffset);
 		if (udf_write_fi(inode, sfi, dfi, &dfibh, sfi->impUse,
-				 sfi->fileIdent +
-					le16_to_cpu(sfi->lengthOfImpUse))) {
+				 udf_get_fi_ident(sfi))) {
 			iinfo->i_alloc_type = ICBTAG_FLAG_AD_IN_ICB;
 			brelse(dbh);
 			return NULL;

fs/udf/namei.c

@@ -74,12 +74,11 @@ int udf_write_fi(struct inode *inode, struct fileIdentDesc *cfi,
 
 	if (fileident) {
 		if (adinicb || (offset + lfi < 0)) {
-			memcpy((uint8_t *)sfi->fileIdent + liu, fileident, lfi);
+			memcpy(udf_get_fi_ident(sfi), fileident, lfi);
 		} else if (offset >= 0) {
 			memcpy(fibh->ebh->b_data + offset, fileident, lfi);
 		} else {
-			memcpy((uint8_t *)sfi->fileIdent + liu, fileident,
-				-offset);
+			memcpy(udf_get_fi_ident(sfi), fileident, -offset);
 			memcpy(fibh->ebh->b_data, fileident - offset,
 				lfi + offset);
 		}
@@ -88,11 +87,11 @@ int udf_write_fi(struct inode *inode, struct fileIdentDesc *cfi,
 	offset += lfi;
 
 	if (adinicb || (offset + padlen < 0)) {
-		memset((uint8_t *)sfi->padding + liu + lfi, 0x00, padlen);
+		memset(udf_get_fi_ident(sfi) + lfi, 0x00, padlen);
 	} else if (offset >= 0) {
 		memset(fibh->ebh->b_data + offset, 0x00, padlen);
 	} else {
-		memset((uint8_t *)sfi->padding + liu + lfi, 0x00, -offset);
+		memset(udf_get_fi_ident(sfi) + lfi, 0x00, -offset);
 		memset(fibh->ebh->b_data, 0x00, padlen + offset);
 	}
 
@@ -226,7 +225,7 @@ static struct fileIdentDesc *udf_find_entry(struct inode *dir,
 		lfi = cfi->lengthFileIdent;
 
 		if (fibh->sbh == fibh->ebh) {
-			nameptr = fi->fileIdent + liu;
+			nameptr = udf_get_fi_ident(fi);
 		} else {
 			int poffset;	/* Unpaded ending offset */
 
@@ -246,7 +245,7 @@ static struct fileIdentDesc *udf_find_entry(struct inode *dir,
 					}
 				}
 				nameptr = copy_name;
-				memcpy(nameptr, fi->fileIdent + liu,
+				memcpy(nameptr, udf_get_fi_ident(fi),
 					lfi - poffset);
 				memcpy(nameptr + lfi - poffset,
 					fibh->ebh->b_data, poffset);

fs/udf/udfdecl.h

@@ -130,6 +130,10 @@ static inline unsigned int udf_dir_entry_len(struct fileIdentDesc *cfi)
 		le16_to_cpu(cfi->lengthOfImpUse) + cfi->lengthFileIdent,
 		UDF_NAME_PAD);
 }
+static inline uint8_t *udf_get_fi_ident(struct fileIdentDesc *fi)
+{
+	return ((uint8_t *)(fi + 1)) + le16_to_cpu(fi->lengthOfImpUse);
+}
 
 /* file.c */
 extern long udf_ioctl(struct file *, unsigned int, unsigned long);