overlayfs syncs all inode pages on sync_filesystem(), but it also
needs to call s_op->sync_fs() of upper fs for metadata sync.
This should fix correctness of syncfs(2) and fsfreeze(8).
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/overlayfs/super.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 0f8a9c8..5dc1d42 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -160,6 +160,25 @@ static void ovl_put_super(struct super_block *sb)
kfree(ufs);
}
+static int ovl_sync_fs(struct super_block *sb, int wait)
+{
+ struct ovl_fs *ufs = sb->s_fs_info;
+ struct super_block *upper_sb;
+ int ret;
+
+ if (!ufs->upper_mnt)
+ return 0;
+ upper_sb = ufs->upper_mnt->mnt_sb;
+ if (!upper_sb->s_op->sync_fs)
+ return 0;
+
+ /* real inodes have already been synced by sync_filesystem(ovl_sb) */
+ down_read(&upper_sb->s_umount);
+ ret = upper_sb->s_op->sync_fs(upper_sb, wait);
+ up_read(&upper_sb->s_umount);
+ return ret;
+}
+
static int ovl_freeze(struct super_block *sb)
{
struct ovl_fs *ufs = sb->s_fs_info;
@@ -236,6 +255,7 @@ static int ovl_remount(struct super_block *sb, int *flags, char *data)
static const struct super_operations ovl_super_operations = {
.put_super = ovl_put_super,
+ .sync_fs = ovl_sync_fs,
.freeze_fs = ovl_freeze,
.unfreeze_fs = ovl_unfreeze,
.statfs = ovl_statfs,
--
2.7.4
--
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