Re: [PATCH v3 2/2] block/export/fuse: Fix build failure on FreeBSD

[Hanna Reitz]

On 01.02.22 12:26, Philippe Mathieu-Daudé wrote:
> When building on FreeBSD we get:
>
>    [816/6851] Compiling C object libblockdev.fa.p/block_export_fuse.c.o
>    ../block/export/fuse.c:628:16: error: use of undeclared identifier 
> 'FALLOC_FL_KEEP_SIZE'
>        if (mode & FALLOC_FL_KEEP_SIZE) {
>                   ^
>    ../block/export/fuse.c:651:16: error: use of undeclared identifier 
> 'FALLOC_FL_PUNCH_HOLE'
>        if (mode & FALLOC_FL_PUNCH_HOLE) {
>                   ^
>    ../block/export/fuse.c:652:22: 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 | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/block/export/fuse.c b/block/export/fuse.c
> index d25e478c0a2..fdda8e3c818 100644
> --- a/block/export/fuse.c
> +++ b/block/export/fuse.c
> @@ -625,9 +625,11 @@ static void fuse_fallocate(fuse_req_t req, fuse_ino_t 
> inode, int mode,
>           return;
>       }
>   
> +#ifdef CONFIG_FALLOCATE_PUNCH_HOLE
>       if (mode & FALLOC_FL_KEEP_SIZE) {
>           length = MIN(length, blk_len - offset);
>       }
> +#endif /* CONFIG_FALLOCATE_PUNCH_HOLE */
>   
>       if (!mode) {
>           /* We can only fallocate at the EOF with a truncate */
> @@ -648,6 +650,7 @@ static void fuse_fallocate(fuse_req_t req, fuse_ino_t 
> inode, int mode,
>           ret = fuse_do_truncate(exp, offset + length, true,
>                                  PREALLOC_MODE_FALLOC);
>       }
> +#ifdef CONFIG_FALLOCATE_PUNCH_HOLE
>       else if (mode & FALLOC_FL_PUNCH_HOLE) {
>           if (!(mode & FALLOC_FL_KEEP_SIZE)) {
>               fuse_reply_err(req, EINVAL);
> @@ -662,6 +665,7 @@ static void fuse_fallocate(fuse_req_t req, fuse_ino_t 
> inode, int mode,
>               length -= size;
>           } while (ret == 0 && length > 0);
>       }
> +#endif /* CONFIG_FALLOCATE_PUNCH_HOLE */
>   #ifdef CONFIG_FALLOCATE_ZERO_RANGE
>       else if (mode & FALLOC_FL_ZERO_RANGE) {
>           if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + length > blk_len) {

I believe CONFIG_FALLOCATE_ZERO_RANGE only guarantees the presence of 
FALLOC_FL_ZERO_RANGE, so we probably should check for 
CONFIG_FALLOCATE_PUNCH_HOLE, too, here.

(Maybe in practice FALLOC_FL_ZERO_RANGE guarantees that 
FALLOC_FL_KEEP_SIZE exists, too, but then a check just wouldn’t hurt.)

Hanna