[PATCH 2/3] punch-alternating: use the block size reported by the fs for punching

Darrick J. Wong
2016-02-15T20:46:26Z

When we're trying to punch alternating blocks out of a file, use the
bsize reported by fstatfs so that we can punch out single blocks.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
src/punch-alternating.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/punch-alternating.c b/src/punch-alternating.c
index 9566310..4148622 100644
--- a/src/punch-alternating.c
+++ b/src/punch-alternating.c
@@ -14,6 +14,7 @@
int main(int argc, char *argv[])
{
struct stat s;
+ struct statfs sf;
off_t offset;
int fd;
blksize_t blksz;
@@ -35,8 +36,12 @@ int main(int argc, char *argv[])
if (error)
goto err;

+ error = fstatfs(fd, &sf);
+ if (error)
+ goto err;
+
sz = s.st_size;
- blksz = s.st_blksize;
+ blksz = sf.f_bsize;

mode = FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE;
for (offset = 0; offset < sz; offset += blksz * 2) {