X-Git-Url: https://git.sven.stormbind.net/?p=sven%2Fexfat-utils.git;a=blobdiff_plain;f=libexfat%2Fmount.c;h=295d455eff73a6d5158f47cff4634b147dd9d423;hp=4240f63b7a34efece8f08f30db1feb241e64bb44;hb=dbe4348df2ba88986e13163ef13d09fb7247589d;hpb=4cb393cfd9b0ab69392612521ee3dbe481ec492d

diff --git a/libexfat/mount.c b/libexfat/mount.c
index 4240f63..295d455 100644
--- a/libexfat/mount.c
+++ b/libexfat/mount.c
@@ -116,6 +116,30 @@ static int verify_vbr_checksum(void* sector, off_t sector_size, int fd)
 	return 0;
 }
 
+static int commit_super_block(const struct exfat* ef)
+{
+	exfat_write_raw(ef->sb, sizeof(struct exfat_super_block), 0, ef->fd);
+	if (fsync(ef->fd) < 0)
+	{
+		exfat_error("fsync failed");
+		return 1;
+	}
+	return 0;
+}
+
+static int prepare_super_block(const struct exfat* ef)
+{
+	if (le16_to_cpu(ef->sb->volume_state) & EXFAT_STATE_MOUNTED)
+		exfat_warn("volume was not unmounted cleanly");
+
+	if (ef->ro)
+		return 0;
+
+	ef->sb->volume_state = cpu_to_le16(
+			le16_to_cpu(ef->sb->volume_state) | EXFAT_STATE_MOUNTED);
+	return commit_super_block(ef);
+}
+
 int exfat_mount(struct exfat* ef, const char* spec, const char* options)
 {
 	int rc;
@@ -123,23 +147,29 @@ int exfat_mount(struct exfat* ef, const char* spec, const char* options)
 	tzset();
 	memset(ef, 0, sizeof(struct exfat));
 
-	ef->sb = malloc(sizeof(struct exfat_super_block));
-	if (ef->sb == NULL)
-	{
-		exfat_error("memory allocation failed");
-		return -ENOMEM;
-	}
-	memset(ef->sb, 0, sizeof(struct exfat_super_block));
-
 	parse_options(ef, options);
 
 	ef->fd = exfat_open(spec, ef->ro);
 	if (ef->fd < 0)
 	{
-		free(ef->sb);
-		return -EIO;
+		if (ef->ro || !match_option(options, "ro_fallback"))
+			return -EIO;
+		ef->fd = exfat_open(spec, 1);
+		if (ef->fd < 0)
+			return -EIO;
+		exfat_warn("device is write-protected, mounting read-only");
+		ef->ro_fallback = ef->ro = 1;
 	}
 
+	ef->sb = malloc(sizeof(struct exfat_super_block));
+	if (ef->sb == NULL)
+	{
+		close(ef->fd);
+		exfat_error("failed to allocate memory for the super block");
+		return -ENOMEM;
+	}
+	memset(ef->sb, 0, sizeof(struct exfat_super_block));
+
 	exfat_read_raw(ef->sb, sizeof(struct exfat_super_block), 0, ef->fd);
 	if (memcmp(ef->sb->oem_name, "EXFAT   ", 8) != 0)
 	{
@@ -173,28 +203,29 @@ int exfat_mount(struct exfat* ef, const char* spec, const char* options)
 		return -EIO;
 	}
 
-	ef->zero_sector = malloc(SECTOR_SIZE(*ef->sb));
-	if (ef->zero_sector == NULL)
+	ef->zero_cluster = malloc(CLUSTER_SIZE(*ef->sb));
+	if (ef->zero_cluster == NULL)
 	{
 		close(ef->fd);
 		free(ef->sb);
 		exfat_error("failed to allocate zero sector");
 		return -ENOMEM;
 	}
-	/* use zero_sector as a temporary buffer for VBR checksum verification */
-	if (verify_vbr_checksum(ef->zero_sector, SECTOR_SIZE(*ef->sb), ef->fd) != 0)
+	/* use zero_cluster as a temporary buffer for VBR checksum verification */
+	if (verify_vbr_checksum(ef->zero_cluster, SECTOR_SIZE(*ef->sb),
+			ef->fd) != 0)
 	{
-		free(ef->zero_sector);
+		free(ef->zero_cluster);
 		close(ef->fd);
 		free(ef->sb);
 		return -EIO;
 	}
-	memset(ef->zero_sector, 0, SECTOR_SIZE(*ef->sb));
+	memset(ef->zero_cluster, 0, CLUSTER_SIZE(*ef->sb));
 
 	ef->root = malloc(sizeof(struct exfat_node));
 	if (ef->root == NULL)
 	{
-		free(ef->zero_sector);
+		free(ef->zero_cluster);
 		close(ef->fd);
 		free(ef->sb);
 		exfat_error("failed to allocate root node");
@@ -226,33 +257,57 @@ int exfat_mount(struct exfat* ef, const char* spec, const char* options)
 		goto error;
 	}
 
+	if (prepare_super_block(ef) != 0)
+		goto error;
+
 	return 0;
 
 error:
 	exfat_put_node(ef, ef->root);
 	exfat_reset_cache(ef);
 	free(ef->root);
-	free(ef->zero_sector);
+	free(ef->zero_cluster);
 	close(ef->fd);
 	free(ef->sb);
 	return -EIO;
 }
 
+static void finalize_super_block(struct exfat* ef)
+{
+	if (ef->ro)
+		return;
+
+	ef->sb->volume_state = cpu_to_le16(
+			le16_to_cpu(ef->sb->volume_state) & ~EXFAT_STATE_MOUNTED);
+
+	/* Some implementations set the percentage of allocated space to 0xff
+	   on FS creation and never update it. In this case leave it as is. */
+	if (ef->sb->allocated_percent != 0xff)
+	{
+		uint32_t free, total;
+
+		free = exfat_count_free_clusters(ef);
+		total = le32_to_cpu(ef->sb->cluster_count);
+		ef->sb->allocated_percent = ((total - free) * 100 + total / 2) / total;
+	}
+
+	commit_super_block(ef);
+}
+
 void exfat_unmount(struct exfat* ef)
 {
 	exfat_put_node(ef, ef->root);
 	exfat_reset_cache(ef);
 	free(ef->root);
 	ef->root = NULL;
-	free(ef->zero_sector);
-	ef->zero_sector = NULL;
-	free(ef->cmap.chunk);
-	ef->cmap.chunk = NULL;
-	if (fsync(ef->fd) < 0)
-		exfat_error("fsync failed");
-	if (close(ef->fd) < 0)
+	finalize_super_block(ef);
+	if (close(ef->fd) < 0)	/* close descriptor immediately after fsync */
 		exfat_error("close failed");
 	ef->fd = 0;
+	free(ef->zero_cluster);
+	ef->zero_cluster = NULL;
+	free(ef->cmap.chunk);
+	ef->cmap.chunk = NULL;
 	free(ef->sb);
 	ef->sb = NULL;
 	free(ef->upcase);