libfdisk: add fdisk_wipe_partition()

Now libfdisk provides functionality wipe disk device only ([s]fdisk
option --wipe).

This patch allows to probe for filesystems/RAIDs on newly created
partitions.  It means we can remove signatures before the partition
node (device) is created. This reduces udev events and it's
unnecessary to call wipefs for all partitions.  For example

  sfdisk --wipe=always --wipe-partitions=always /dev/sda <<<
  ...
  EOF

is a elegant way how to create new disk layout without any obsolete
filesystems/RAIDs.

Signed-off-by: Karel Zak <kzak@redhat.com>

libfdisk/docs/libfdisk-sections.txt

@@ -162,6 +162,7 @@ fdisk_delete_partition
 fdisk_get_partition
 fdisk_is_partition_used
 fdisk_set_partition
+fdisk_wipe_partition
 <SUBSECTION>
 fdisk_partition
 fdisk_new_partition

libfdisk/src/Makemodule.am

@@ -21,6 +21,7 @@ libfdisk_la_SOURCES = \
 	libfdisk/src/iter.c \
 	libfdisk/src/script.c \
 	libfdisk/src/version.c \
+	libfdisk/src/wipe.c \
 	\
 	libfdisk/src/sun.c \
 	libfdisk/src/sgi.c \

libfdisk/src/context.c

@@ -47,6 +47,8 @@ struct fdisk_context *fdisk_new_context(void)
 	cxt->dev_fd = -1;
 	cxt->refcount = 1;
 
+	INIT_LIST_HEAD(&cxt->wipes);
+
 	/*
 	 * Allocate label specific structs.
 	 *
@@ -112,6 +114,8 @@ static int init_nested_from_parent(struct fdisk_context *cxt, int isnew)
 			return -ENOMEM;
 	}
 
+	INIT_LIST_HEAD(&cxt->wipes);
+
 	return 0;
 }
 
@@ -339,17 +343,24 @@ int fdisk_enable_bootbits_protection(struct fdisk_context *cxt, int enable)
  * @cxt: fdisk context
  * @enable: 1 or 0
  *
- * The library removes all filesystem/RAID signatures before write PT. This is
- * no-op if any collision has not been detected by fdisk_assign_device(). See
- * fdisk_has_collision(). The default is not wipe a device.
+ * The library removes all filesystem/RAID signatures before it writes
+ * partition table. The probing area where it looks for filesystem/RAID is from
+ * the begin of the disk. The device is wiped by libblkid.
+ *
+ * See also fdisk_wipe_partition().
+ *
+ * This is no-op if any collision has not been detected by
+ * fdisk_assign_device(). See fdisk_has_collision(). The default is not wipe a
+ * device.
  *
  * Returns: 0 on success, < 0 on error.
  */
 int fdisk_enable_wipe(struct fdisk_context *cxt, int enable)
 {
 	if (!cxt)
 		return -EINVAL;
-	cxt->wipe_device = enable ? 1 : 0;
+
+	fdisk_set_wipe_area(cxt, 0, cxt->total_sectors * cxt->sector_size, enable);
 	return 0;
 }
 
@@ -363,7 +374,10 @@ int fdisk_enable_wipe(struct fdisk_context *cxt, int enable)
  */
 int fdisk_has_wipe(struct fdisk_context *cxt)
 {
-	return cxt && cxt->wipe_device;
+	if (!cxt)
+		return 0;
+
+	return fdisk_has_wipe_area(cxt, 0, cxt->total_sectors * cxt->sector_size);
 }
 
 
@@ -484,6 +498,8 @@ static void reset_context(struct fdisk_context *cxt)
 	cxt->script = NULL;
 
 	cxt->label = NULL;
+
+	fdisk_free_wipe_areas(cxt);
 }
 
 /*
@@ -535,37 +551,6 @@ static int check_collisions(struct fdisk_context *cxt)
 #endif
 }
 
-int fdisk_wipe_collisions(struct fdisk_context *cxt)
-{
-#ifdef HAVE_LIBBLKID
-	blkid_probe pr;
-	int rc;
-
-	assert(cxt);
-	assert(cxt->dev_fd >= 0);
-
-	DBG(CXT, ul_debugobj(cxt, "wipe: initialize libblkid prober"));
-
-	pr = blkid_new_probe();
-	if (!pr)
-		return -ENOMEM;
-	rc = blkid_probe_set_device(pr, cxt->dev_fd, 0, 0);
-	if (rc)
-		return rc;
-
-	blkid_probe_enable_superblocks(pr, 1);
-	blkid_probe_set_superblocks_flags(pr, BLKID_SUBLKS_MAGIC);
-	blkid_probe_enable_partitions(pr, 1);
-	blkid_probe_set_partitions_flags(pr, BLKID_PARTS_MAGIC);
-
-	while (blkid_do_probe(pr) == 0)
-		blkid_do_wipe(pr, FALSE);
-
-	blkid_free_probe(pr);
-#endif
-	return 0;
-}
-
 /**
  * fdisk_assign_device:
  * @cxt: context

libfdisk/src/fdiskP.h

@@ -38,6 +38,7 @@
 #define LIBFDISK_DEBUG_PARTTYPE	(1 << 7)
 #define LIBFDISK_DEBUG_TAB	(1 << 8)
 #define LIBFDISK_DEBUG_SCRIPT	(1 << 9)
+#define LIBFDISK_DEBUG_WIPE	(1 << 10)
 #define LIBFDISK_DEBUG_ALL	0xFFFF
 
 UL_DEBUG_DECLARE_MASK(libfdisk);
@@ -121,6 +122,10 @@ struct fdisk_partition {
 	char		*attrs;			/* partition flags/attributes converted to string */
 	struct fdisk_parttype	*type;		/* partition type */
 
+	char		*fstype;		/* filesystem type */
+	char		*fsuuid;		/* filesystem uuid  */
+	char		*fslabel;		/* filesystem label */
+
 	struct list_head	parts;		/* list of partitions */
 
 	/* extra fields for partition_to_string() */
@@ -143,6 +148,7 @@ struct fdisk_partition {
 			partno_follow_default : 1,	/* use default partno */
 			size_explicit : 1,		/* don't align the size */
 			start_follow_default : 1,	/* use default start */
+			fs_probed : 1,			/* already probed by blkid */
 			used : 1,			/* partition already used */
 			wholedisk : 1;			/* special system partition */
 };
@@ -355,10 +361,10 @@ struct fdisk_context {
 		     display_in_cyl_units : 1,	/* for obscure labels */
 		     display_details : 1,	/* expert display mode */
 		     protect_bootbits : 1,	/* don't zeroize fll irst sector */
-		     wipe_device : 1,		/* wipe device before write */
 		     listonly : 1;		/* list partition, nothing else */
 
 	char *collision;			/* name of already existing FS/PT */
+	struct list_head wipes;			/* list of areas to wipe before write */
 
 	int sizeunit;				/* SIZE fields, FDISK_SIZEUNIT_* */
 
@@ -389,8 +395,6 @@ struct fdisk_context {
 	struct fdisk_script	*script;	/* what we want to follow */
 };
 
-int fdisk_wipe_collisions(struct fdisk_context *cxt);
-
 /* context.c */
 extern int __fdisk_switch_label(struct fdisk_context *cxt,
 				    struct fdisk_label *lb);
@@ -455,4 +459,10 @@ extern struct dos_partition *fdisk_dos_get_partition(
 				struct fdisk_context *cxt,
 				size_t i);
 
+/* wipe.c */
+void fdisk_free_wipe_areas(struct fdisk_context *cxt);
+int fdisk_set_wipe_area(struct fdisk_context *cxt, uint64_t start, uint64_t size, int enable);
+int fdisk_do_wipe(struct fdisk_context *cxt);
+int fdisk_has_wipe_area(struct fdisk_context *cxt, uint64_t start, uint64_t size);
+
 #endif /* _LIBFDISK_PRIVATE_H */

libfdisk/src/init.c

@@ -21,6 +21,7 @@ UL_DEBUG_DEFINE_MASKNAMES(libfdisk) =
 	{ "parttype",	LIBFDISK_DEBUG_PARTTYPE,"partition type utils" },
 	{ "script",	LIBFDISK_DEBUG_SCRIPT,	"sfdisk-like scripts" },
 	{ "tab",	LIBFDISK_DEBUG_TAB,	"table utils"},
+	{ "wipe",       LIBFDISK_DEBUG_WIPE,    "wipe area utils" },
 	{ NULL, 0 }
 };
 

libfdisk/src/label.c

@@ -304,11 +304,7 @@ int fdisk_write_disklabel(struct fdisk_context *cxt)
 	if (!cxt->label->op->write)
 		return -ENOSYS;
 
-	if (cxt->collision && cxt->wipe_device) {
-		int rc = fdisk_wipe_collisions(cxt);
-		if (rc)
-			return rc;
-	}
+	fdisk_do_wipe(cxt);
 	return cxt->label->op->write(cxt);
 }
 

libfdisk/src/libfdisk.h.in

@@ -285,6 +285,10 @@ enum fdisk_fieldtype {
 	FDISK_FIELD_SADDR,		/* Start-C/H/S (MBR) */
 	FDISK_FIELD_UUID,		/* partition UUID (GPT) */
 
+	FDISK_FIELD_FSUUID,
+	FDISK_FIELD_FSLABEL,
+	FDISK_FIELD_FSTYPE,
+
 	FDISK_NFIELDS		/* must be last */
 };
 
@@ -321,9 +325,10 @@ extern int fdisk_get_partition(struct fdisk_context *cxt, size_t partno, struct
 extern int fdisk_set_partition(struct fdisk_context *cxt, size_t partno, struct fdisk_partition *pa);
 extern int fdisk_add_partition(struct fdisk_context *cxt, struct fdisk_partition *pa, size_t *partno);
 extern int fdisk_delete_partition(struct fdisk_context *cxt, size_t partno);
-
 extern int fdisk_delete_all_partitions(struct fdisk_context *cxt);
 
+extern int fdisk_wipe_partition(struct fdisk_context *cxt, size_t partno, int enable);
+
 extern int fdisk_set_partition_type(struct fdisk_context *cxt, size_t partnum,
 			     struct fdisk_parttype *t);
 
@@ -389,6 +394,7 @@ size_t fdisk_partition_get_partno(struct fdisk_partition *pa);
 int fdisk_partition_has_partno(struct fdisk_partition *pa);
 int fdisk_partition_cmp_partno(struct fdisk_partition *a,
 	                               struct fdisk_partition *b);
+
 int fdisk_partition_partno_follow_default(struct fdisk_partition *pa, int enable);
 
 extern int fdisk_partition_set_type(struct fdisk_partition *pa, struct fdisk_parttype *type);

libfdisk/src/libfdisk.sym

@@ -259,3 +259,7 @@ FDISK_2.28 {
 	fdisk_get_collision;
 	fdisk_has_wipe;
 } FDISK_2.27;
+
+FDISK_2.29 {
+	fdisk_wipe_partition;
+} FDISK_2.28;