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-rw-r--r--fs/overlayfs/super.c19
1 files changed, 15 insertions, 4 deletions
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 13a8a8617e44..76440feb79f6 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -252,6 +252,7 @@ static void ovl_put_super(struct super_block *sb)
ovl_free_fs(ofs);
}
+/* Sync real dirty inodes in upper filesystem (if it exists) */
static int ovl_sync_fs(struct super_block *sb, int wait)
{
struct ovl_fs *ofs = sb->s_fs_info;
@@ -260,14 +261,24 @@ static int ovl_sync_fs(struct super_block *sb, int wait)
if (!ofs->upper_mnt)
return 0;
- upper_sb = ofs->upper_mnt->mnt_sb;
- if (!upper_sb->s_op->sync_fs)
+
+ /*
+ * If this is a sync(2) call or an emergency sync, all the super blocks
+ * will be iterated, including upper_sb, so no need to do anything.
+ *
+ * If this is a syncfs(2) call, then we do need to call
+ * sync_filesystem() on upper_sb, but enough if we do it when being
+ * called with wait == 1.
+ */
+ if (!wait)
return 0;
- /* real inodes have already been synced by sync_filesystem(ovl_sb) */
+ upper_sb = ofs->upper_mnt->mnt_sb;
+
down_read(&upper_sb->s_umount);
- ret = upper_sb->s_op->sync_fs(upper_sb, wait);
+ ret = sync_filesystem(upper_sb);
up_read(&upper_sb->s_umount);
+
return ret;
}