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authorAmir Goldstein <amir73il@gmail.com>2017-01-23 15:32:21 +0300
committerMiklos Szeredi <mszeredi@redhat.com>2017-02-07 17:47:14 +0300
commite593b2bf513dd4d3fbfa0f435392eea2c7f776f0 (patch)
tree02d6f1b258c50b74ad8213c2d5ca0aa4c59dd16e /fs/overlayfs
parent01ad3eb8a07385bc8849f0ee7c800e7c8bd7287e (diff)
downloadlinux-e593b2bf513dd4d3fbfa0f435392eea2c7f776f0.tar.xz
ovl: properly implement sync_filesystem()
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 fixes correctness of syncfs(2) as demonstrated by following xfs specific test: xfs_sync_stats() { echo $1 echo -n "xfs_log_force = " grep log /proc/fs/xfs/stat | awk '{ print $5 }' } xfs_sync_stats "before touch" touch x xfs_sync_stats "after touch" xfs_io -c syncfs . xfs_sync_stats "after syncfs" xfs_io -c fsync x xfs_sync_stats "after fsync" xfs_io -c fsync x xfs_sync_stats "after fsync #2" When this test is run in overlay mount over xfs, log force count does not increase with syncfs command. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/overlayfs')
-rw-r--r--fs/overlayfs/super.c20
1 files changed, 20 insertions, 0 deletions
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 6792bb70b4ac..346f668e7df0 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;
+}
+
/**
* ovl_statfs
* @sb: The overlayfs super block
@@ -222,6 +241,7 @@ 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,
.statfs = ovl_statfs,
.show_options = ovl_show_options,
.remount_fs = ovl_remount,