fs/fat/fatent.c: add cond_resched() to fat_count_free_clusters()

[ Upstream commit ac081c3be3fae6d0cc3e1862507fca3862d30b67 ]

On non-preempt kernels this loop can take a long time (more than 50 ticks)
processing through entries.

Link: http://lkml.kernel.org/r/20181010172623.57033-1-khazhy@google.com
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c
index a40f36b..9635df9 100644 (file)
--- a/fs/fat/fatent.c
+++ b/fs/fat/fatent.c
@@ -681,6 +681,7 @@ int fat_count_free_clusters(struct super_block *sb)
                        if (ops->ent_get(&fatent) == FAT_ENT_FREE)
                                free++;
                } while (fat_ent_next(sbi, &fatent));
+               cond_resched();
        }
        sbi->free_clusters = free;
        sbi->free_clus_valid = 1;