[PATCH v2 3/3] block/export/fuse: Fix build failure on FreeBSD

[Philippe Mathieu-Daudé]

When building on FreeBSD we get:

  [816/6851] Compiling C object libblockdev.fa.p/block_export_fuse.c.o
  ../block/export/fuse.c:612:16: error: use of undeclared identifier 
'FALLOC_FL_KEEP_SIZE'
      if (mode & FALLOC_FL_KEEP_SIZE) {
                 ^
  ../block/export/fuse.c:616:16: error: use of undeclared identifier 
'FALLOC_FL_PUNCH_HOLE'
      if (mode & FALLOC_FL_PUNCH_HOLE) {
                 ^
  ../block/export/fuse.c:619:22: error: use of undeclared identifier 
'FALLOC_FL_KEEP_SIZE'
          if (!(mode & FALLOC_FL_KEEP_SIZE)) {
                       ^
  3 errors generated.
  FAILED: libblockdev.fa.p/block_export_fuse.c.o

Meson indeed reported FALLOC_FL_PUNCH_HOLE is not available:

  C compiler for the host machine: cc (clang 10.0.1 "FreeBSD clang version 
10.0.1")
  Checking for function "fallocate" : NO
  Checking for function "posix_fallocate" : YES
  Header <linux/falloc.h> has symbol "FALLOC_FL_PUNCH_HOLE" : NO
  Header <linux/falloc.h> has symbol "FALLOC_FL_ZERO_RANGE" : NO
  ...

Similarly to commit 304332039 ("block/export/fuse.c: fix musl build"),
guard the code requiring FALLOC_FL_KEEP_SIZE / FALLOC_FL_PUNCH_HOLE
definitions under CONFIG_FALLOCATE_PUNCH_HOLE #ifdef'ry.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 block/export/fuse.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/block/export/fuse.c b/block/export/fuse.c
index 3a158342c75..4c5d662be87 100644
--- a/block/export/fuse.c
+++ b/block/export/fuse.c
@@ -607,6 +607,7 @@ static bool fuse_fallocate_punch_hole(fuse_req_t req, 
fuse_ino_t inode,
                                       int mode, int64_t blk_len,
                                       off_t offset, off_t *length)
 {
+#ifdef CONFIG_FALLOCATE_PUNCH_HOLE
     FuseExport *exp = fuse_req_userdata(req);
 
     if (mode & FALLOC_FL_KEEP_SIZE) {
@@ -629,6 +630,7 @@ static bool fuse_fallocate_punch_hole(fuse_req_t req, 
fuse_ino_t inode,
             *length -= size;
         } while (ret == 0 && *length > 0);
     }
+#endif /* CONFIG_FALLOCATE_PUNCH_HOLE */
     return true;
 }
 
-- 
2.34.1