4.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Damien Le Moal <redacted>

commit acfd2810c75b0625897fc119a2d3a9c26cc0e405 upstream.

clear_prefree_segments() issues small discards after discarding full
segments. These small discards may not be section aligned, so not zone
aligned on a zoned block device, causing __f2fs_iissue_discard_zone() to fail.
Fix this by not issuing small discards for a volume mounted with the BLKZONED
feature enabled.

Signed-off-by: Damien Le Moal <redacted>
Reviewed-by: Chao Yu <redacted>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/f2fs/segment.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c

@@ -1329,7 +1329,8 @@ find_next:
 					sbi->blocks_per_seg, cur_pos);
 			len = next_pos - cur_pos;
 
-			if (force && len < cpc->trim_minlen)
+			if (f2fs_sb_mounted_blkzoned(sbi->sb) ||
+			    (force && len < cpc->trim_minlen))
 				goto skip;
 
 			f2fs_issue_discard(sbi, entry->start_blkaddr + cur_pos,