The field is unused (only ever set, but never read) since commit
ac9185603. Additionally, the commit message of commit 34fa110e already
explained earlier why it's unreliable. Remove it.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/file-posix.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/block/file-posix.c b/block/file-posix.c
index 256de1f456..47c14430c8 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -154,7 +154,6 @@ typedef struct BDRVRawState {
 
     bool has_discard:1;
     bool has_write_zeroes:1;
-    bool discard_zeroes:1;
     bool use_linux_aio:1;
     bool use_linux_io_uring:1;
     int page_cache_inconsistent; /* errno from fdatasync failure */
@@ -755,7 +754,6 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
             ret = -EINVAL;
             goto fail;
         } else {
-            s->discard_zeroes = true;
             s->has_fallocate = true;
         }
     } else {
@@ -769,19 +767,12 @@ static int raw_open_common(BlockDriverState *bs, QDict *options,
     }
 
     if (S_ISBLK(st.st_mode)) {
-#ifdef BLKDISCARDZEROES
-        unsigned int arg;
-        if (ioctl(s->fd, BLKDISCARDZEROES, &arg) == 0 && arg) {
-            s->discard_zeroes = true;
-        }
-#endif
 #ifdef __linux__
         /* On Linux 3.10, BLKDISCARD leaves stale data in the page cache.  Do
          * not rely on the contents of discarded blocks unless using O_DIRECT.
          * Same for BLKZEROOUT.
          */
         if (!(bs->open_flags & BDRV_O_NOCACHE)) {
-            s->discard_zeroes = false;
             s->has_write_zeroes = false;
         }
 #endif
-- 
2.37.3