Refactor index and I/O constants usage

- Use defined constants for index parsing and I/O operations
- Enhance clarity by replacing magic numbers with named constants

Author: zombocoder

bfc_format.c

@@ -144,13 +144,13 @@ bfc_parse_index_entry(const uint8_t *buf, size_t buflen, size_t *offset,
 	size_t remaining = buflen - *offset;
 	uint32_t path_len;
 
-	/* Need at least 4 bytes for path_len */
-	if (remaining < 4)
+	/* Need at least BFC_PATH_LEN_SIZE bytes for path_len */
+	if (remaining < BFC_PATH_LEN_SIZE)
 		return (EINVAL);
 
 	/* Read path length (32-bit) */
 	READ_LE32(p, path_len);
-	remaining -= 4;
+	remaining -= BFC_PATH_LEN_SIZE;
 
 	/* Sanity check path length */
 	if (path_len == 0 || path_len > BFC_MAX_PATH_LEN || path_len > remaining)
@@ -191,6 +191,8 @@ int
 bfc_read_index(struct bfcfs_mount *bmp, struct thread *td)
 {
 	uint8_t *index_buf = NULL;
+	uint8_t *p;
+	uint32_t version, count;
 	size_t offset = 0;
 	int error, i;
 
@@ -222,13 +224,13 @@ bfc_read_index(struct bfcfs_mount *bmp, struct thread *td)
 	}
 
 	/* Parse index header (version and count) */
-	uint32_t version, count;
-	uint8_t *p = index_buf;
+	p = index_buf;
 	READ_LE32(p, version);
 	READ_LE32(p, count);
 
-	if (version != 1) {
-		BFCFS_ERR("unsupported index version: %u", version);
+	if (version != BFC_INDEX_VERSION) {
+		BFCFS_ERR("unsupported index version: %u (expected %u)",
+		    version, BFC_INDEX_VERSION);
 		free(index_buf, M_BFCFS);
 		return (EINVAL);
 	}
@@ -247,11 +249,11 @@ bfc_read_index(struct bfcfs_mount *bmp, struct thread *td)
 	bmp->index = malloc(bmp->num_entries * sizeof(struct bfcfs_index_entry),
 	    M_BFCFS, M_WAITOK | M_ZERO);
 
-	/* Parse all entries (starting after 8-byte header) */
-	offset = 8;
+	/* Parse all entries (starting after index header) */
+	offset = BFC_INDEX_HEADER_SIZE;
 	for (i = 0; i < (int)bmp->num_entries; i++) {
 		error = bfc_parse_index_entry(index_buf, bmp->footer.index_size,
-		    &offset, &bmp->index[i], i + 1);  /* inode numbers start at 1 */
+		    &offset, &bmp->index[i], i + BFC_INODE_START);
 		if (error) {
 			BFCFS_ERR("failed to parse index entry %d: %d", i, error);
 			goto fail;

bfc_io.c

@@ -78,9 +78,9 @@ bfc_crc32c(const void *buf, size_t len)
 {
 	/*
 	 * calculate_crc32c() from FreeBSD already handles initialization and XOR
-	 * Just pass 0 as initial CRC for a new calculation
+	 * Just pass BFC_CRC32C_INIT as initial CRC for a new calculation
 	 */
-	return calculate_crc32c(0, buf, len);
+	return calculate_crc32c(BFC_CRC32C_INIT, buf, len);
 }
 
 /*

bfcfs.h

@@ -43,8 +43,11 @@
 #define BFC_MAX_PATH_LEN	4096		/* Maximum path length */
 
 /* BFC index format constants */
+#define BFC_INDEX_VERSION		1	/* Supported index version */
 #define BFC_INDEX_HEADER_SIZE		8	/* Version (4) + count (4) */
 #define BFC_INDEX_ENTRY_METADATA_SIZE	48	/* Size of fixed metadata fields */
+#define BFC_PATH_LEN_SIZE		4	/* Size of path_len field (uint32_t) */
+#define BFC_INODE_START			1	/* First inode number (root is synthetic) */
 
 /* Time conversion constants */
 #define NSEC_PER_SEC		1000000000ULL	/* Nanoseconds per second */
@@ -75,6 +78,10 @@
 #define BFC_NAME_MAX		255		/* Maximum filename length */
 #define BFC_PATH_MAX		1024		/* Maximum path length for pathconf */
 #define BFC_FILESIZEBITS	64		/* File size bits (64-bit offsets) */
+#define BFC_LINK_MAX		1		/* Max hard links (read-only FS) */
+
+/* I/O constants */
+#define BFC_CRC32C_INIT		0		/* Initial CRC32C value */
 
 /* BFC object types */
 #define BFC_TYPE_FILE		1

bfcfs_vfs.c

@@ -137,7 +137,8 @@ bfcfs_mount(struct mount *mp)
 	LIST_INIT(&bmp->index_list);
 
 	/* Parse optional mount options */
-	bmp->verify_crc = 1;  /* Default: verify CRC */
+	bmp->verify_crc = 1;  /* Default: verify CRC enabled */
+	bmp->no_readahead = 0;  /* Default: readahead enabled */
 	if (vfs_getopt(mp->mnt_optnew, "noverify", NULL, NULL) == 0)
 		bmp->verify_crc = 0;
 	if (vfs_getopt(mp->mnt_optnew, "noreadahead", NULL, NULL) == 0)

bfcfs_vnops.c

@@ -14,6 +14,7 @@
 #include <sys/stat.h>
 #include <sys/buf.h>
 #include <sys/bio.h>
+#include <sys/unistd.h>
 #include <vm/vm.h>
 #include <vm/vnode_pager.h>
 
@@ -475,19 +476,19 @@ bfcfs_pathconf(struct vop_pathconf_args *ap)
 	int error = 0;
 
 	switch (ap->a_name) {
-	case 1:	/* _PC_LINK_MAX */
-		*ap->a_retval = 1;
+	case _PC_LINK_MAX:
+		*ap->a_retval = BFC_LINK_MAX;
 		break;
-	case 4:	/* _PC_NAME_MAX */
+	case _PC_NAME_MAX:
 		*ap->a_retval = BFC_NAME_MAX;
 		break;
-	case 5:	/* _PC_PATH_MAX */
+	case _PC_PATH_MAX:
 		*ap->a_retval = BFC_PATH_MAX;
 		break;
-	case 7:	/* _PC_NO_TRUNC */
-		*ap->a_retval = 1;
+	case _PC_NO_TRUNC:
+		*ap->a_retval = 1;	/* Filenames are never truncated */
 		break;
-	case 18:	/* _PC_FILESIZEBITS */
+	case _PC_FILESIZEBITS:
 		*ap->a_retval = BFC_FILESIZEBITS;
 		break;
 	default: