From: Amjad Alsharafi <amjadsharafi10@gmail.com>

Before this commit, the behavior when calling `commit_one_file` for
example with `offset=0x2000` (second cluster), what will happen is that
we won't fetch the next cluster from the fat, and instead use the first
cluster for the read operation.

This is due to off-by-one error here, where `i=0x2000 !< offset=0x2000`,
thus not fetching the next cluster.

Signed-off-by: Amjad Alsharafi <amjadsharafi10@gmail.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Tested-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <b97c1e1f1bc2f776061ae914f95d799d124fcd73.1721470238.git.amjadsharafi10@gmail.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit b881cf00c99e03bc8a3648581f97736ff275b18b)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

diff --git a/block/vvfat.c b/block/vvfat.c
index 9d050ba3ae..19da009a5b 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -2525,8 +2525,9 @@ commit_one_file(BDRVVVFATState* s, int dir_index, uint32_t offset)
         return -1;
     }
 
-    for (i = s->cluster_size; i < offset; i += s->cluster_size)
+    for (i = 0; i < offset; i += s->cluster_size) {
         c = modified_fat_get(s, c);
+    }
 
     fd = qemu_open_old(mapping->path, O_RDWR | O_CREAT | O_BINARY, 0666);
     if (fd < 0) {
-- 
2.39.2