btrfs: get zone information of zoned block devices

If a zoned block device is found, get its zone information (number of
zones and zone size).  To avoid costly run-time zone report
commands to test the device zones type during block allocation, attach
the seq_zones bitmap to the device structure to indicate if a zone is
sequential or accept random writes. Also it attaches the empty_zones
bitmap to indicate if a zone is empty or not.

This patch also introduces the helper function btrfs_dev_is_sequential()
to test if the zone storing a block is a sequential write required zone
and btrfs_dev_is_empty_zone() to test if the zone is a empty zone.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 348f8899f4f4..3c39e363aec5 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -2514,6 +2514,11 @@ static void __init btrfs_print_mod_info(void)
 #ifdef CONFIG_BTRFS_FS_REF_VERIFY
 			", ref-verify=on"
 #endif
+#ifdef CONFIG_BLK_DEV_ZONED
+			", zoned=yes"
+#else
+			", zoned=no"
+#endif
 			;
 	pr_info("Btrfs loaded, crc32c=%s%s\n", crc32c_impl(), options);
 }