[PATCH v2 1/4] erofs-utils: lib: fix short write retries

[Yifan Zhao <stopire@gmail.com>]

Retry with only the remaining byte count in both the pwrite() and
pwrite64() paths.

Assisted-by: Codex:gpt-6-astra
Signed-off-by: Yifan Zhao <stopire@gmail.com>
---
 lib/io.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/io.c b/lib/io.c
index 5c5449f..f62129f 100644
--- a/lib/io.c
+++ b/lib/io.c
@@ -75,9 +75,9 @@ ssize_t erofs_io_pwrite(struct erofs_vfile *vf, const void *buf,
 	pos += vf->offset;
 	do {
 #ifdef HAVE_PWRITE64
-		ret = pwrite64(vf->fd, buf, len, (off64_t)pos);
+		ret = pwrite64(vf->fd, buf, len - written, (off64_t)pos);
 #else
-		ret = pwrite(vf->fd, buf, len, (off_t)pos);
+		ret = pwrite(vf->fd, buf, len - written, (off_t)pos);
 #endif
 		if (ret <= 0) {
 			if (!ret)
-- 
2.55.0