[PATCH v2 1/3] blkid: implement zone-aware probing

[Naohiro Aota <naohiro.aota@wdc.com>]

This patch makes libblkid zone-aware. It can probe the magic located at
some offset from the beginning of some specific zone of a device.

Ths patch introduces some new fields to struct blkid_idmag. They indicate
the magic location is placed related to a zone, and the offset in the zone.

Also, this commit introduces `zone_size` to struct blkid_struct_probe. It
stores the size of zones of a device.

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
---
 configure.ac          |  1 +
 libblkid/src/blkidP.h |  5 +++++
 libblkid/src/probe.c  | 29 +++++++++++++++++++++++++++--
 3 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index bebb4085425a..52b164e834db 100644
--- a/configure.ac
+++ b/configure.ac
@@ -302,6 +302,7 @@ AC_CHECK_HEADERS([ \
 	lastlog.h \
 	libutil.h \
 	linux/btrfs.h \
+	linux/blkzoned.h \
 	linux/capability.h \
 	linux/cdrom.h \
 	linux/falloc.h \
diff --git a/libblkid/src/blkidP.h b/libblkid/src/blkidP.h
index a3fe6748a969..e3a160aa97c0 100644
--- a/libblkid/src/blkidP.h
+++ b/libblkid/src/blkidP.h
@@ -150,6 +150,10 @@ struct blkid_idmag
 	const char	*hoff;		/* hint which contains byte offset to kboff */
 	long		kboff;		/* kilobyte offset of superblock */
 	unsigned int	sboff;		/* byte offset within superblock */
+
+	int		is_zoned;	/* indicate magic location is calcluated based on zone position  */
+	long		zonenum;	/* zone number which has superblock */
+	long		kboff_inzone;	/* kilobyte offset of superblock in a zone */
 };
 
 /*
@@ -206,6 +210,7 @@ struct blkid_struct_probe
 	dev_t			disk_devno;	/* devno of the whole-disk or 0 */
 	unsigned int		blkssz;		/* sector size (BLKSSZGET ioctl) */
 	mode_t			mode;		/* struct stat.sb_mode */
+	uint64_t		zone_size;	/* zone size (BLKGETZONESZ ioctl) */
 
 	int			flags;		/* private library flags */
 	int			prob_flags;	/* always zeroized by blkid_do_*() */
diff --git a/libblkid/src/probe.c b/libblkid/src/probe.c
index a47a8720d4ac..9d180aab5242 100644
--- a/libblkid/src/probe.c
+++ b/libblkid/src/probe.c
@@ -94,6 +94,9 @@
 #ifdef HAVE_LINUX_CDROM_H
 #include <linux/cdrom.h>
 #endif
+#ifdef HAVE_LINUX_BLKZONED_H
+#include <linux/blkzoned.h>
+#endif
 #ifdef HAVE_SYS_STAT_H
 #include <sys/stat.h>
 #endif
@@ -897,6 +900,7 @@ int blkid_probe_set_device(blkid_probe pr, int fd,
 	pr->wipe_off = 0;
 	pr->wipe_size = 0;
 	pr->wipe_chain = NULL;
+	pr->zone_size = 0;
 
 	if (fd < 0)
 		return 1;
@@ -996,6 +1000,15 @@ int blkid_probe_set_device(blkid_probe pr, int fd,
 #endif
 	free(dm_uuid);
 
+# ifdef HAVE_LINUX_BLKZONED_H
+	if (S_ISBLK(sb.st_mode)) {
+		uint32_t zone_size_sector;
+
+		if (!ioctl(pr->fd, BLKGETZONESZ, &zone_size_sector))
+			pr->zone_size = zone_size_sector << 9;
+	}
+# endif
+
 	DBG(LOWPROBE, ul_debug("ready for low-probing, offset=%"PRIu64", size=%"PRIu64"",
 				pr->off, pr->size));
 	DBG(LOWPROBE, ul_debug("whole-disk: %s, regfile: %s",
@@ -1064,12 +1077,24 @@ int blkid_probe_get_idmag(blkid_probe pr, const struct blkid_idinfo *id,
 	/* try to detect by magic string */
 	while(mag && mag->magic) {
 		unsigned char *buf;
+		uint64_t kboff;
 		uint64_t hint_offset;
 
 		if (!mag->hoff || blkid_probe_get_hint(pr, mag->hoff, &hint_offset) < 0)
 			hint_offset = 0;
 
-		off = hint_offset + ((mag->kboff + (mag->sboff >> 10)) << 10);
+		/* If the magic is for zoned device, skip non-zoned device */
+		if (mag->is_zoned && !pr->zone_size) {
+			mag++;
+			continue;
+		}
+
+		if (!mag->is_zoned)
+			kboff = mag->kboff;
+		else
+			kboff = ((mag->zonenum * pr->zone_size) >> 10) + mag->kboff_inzone;
+
+		off = hint_offset + ((kboff + (mag->sboff >> 10)) << 10);
 		buf = blkid_probe_get_buffer(pr, off, 1024);
 
 		if (!buf && errno)
@@ -1079,7 +1104,7 @@ int blkid_probe_get_idmag(blkid_probe pr, const struct blkid_idinfo *id,
 				buf + (mag->sboff & 0x3ff), mag->len)) {
 
 			DBG(LOWPROBE, ul_debug("\tmagic sboff=%u, kboff=%ld",
-				mag->sboff, mag->kboff));
+				mag->sboff, kboff));
 			if (offset)
 				*offset = off + (mag->sboff & 0x3ff);
 			if (res)
-- 
2.31.1