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authorChengguang Xu <cgxu@mykernel.net>2017-11-29 10:01:32 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-08-03 07:50:43 +0200
commit6aaaca7b81e4929a43ac8c0a2a734b762467c60f (patch)
tree2c175c1199a975a4470f5a120e592885a4494315
parent21b5b5e80bcf3f873bf89e9d957a129ea1fdcf36 (diff)
ovl: Sync upper dirty data when syncing overlayfs
commit e8d4bfe3a71537284a90561f77c85dea6c154369 upstream. When executing filesystem sync or umount on overlayfs, dirty data does not get synced as expected on upper filesystem. This patch fixes sync filesystem method to keep data consistency for overlayfs. Signed-off-by: Chengguang Xu <cgxu@mykernel.net> Fixes: e593b2bf513d ("ovl: properly implement sync_filesystem()") Cc: <stable@vger.kernel.org> #4.11 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-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 b8f8d666e8d4..ba20393d60ef 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -232,6 +232,7 @@ static void ovl_put_super(struct super_block *sb)
kfree(ufs);
}
+/* Sync real dirty inodes in upper filesystem (if it exists) */
static int ovl_sync_fs(struct super_block *sb, int wait)
{
struct ovl_fs *ufs = sb->s_fs_info;
@@ -240,14 +241,24 @@ static int ovl_sync_fs(struct super_block *sb, int wait)
if (!ufs->upper_mnt)
return 0;
- upper_sb = ufs->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 = ufs->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;
}