Implement stacked fsync().
Don't sync if lower (noticed by Amir Goldstein).
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
---
fs/overlayfs/file.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index a7af56861aa5..7b47dce4b072 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -233,10 +233,33 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
return ret;
}
+static int ovl_fsync(struct file *file, loff_t start, loff_t end, int datasync)
+{
+ struct fd real;
+ const struct cred *old_cred;
+ int ret;
+
+ ret = ovl_real_fdget(file, &real);
+ if (ret)
+ return ret;
+
+ /* Don't sync lower file for fear of receiving EROFS error */
+ if (file_inode(real.file) == ovl_inode_upper(file_inode(file))) {
+ old_cred = ovl_override_creds(file_inode(file)->i_sb);
+ ret = vfs_fsync_range(real.file, start, end, datasync);
+ revert_creds(old_cred);
+ }
+
+ fdput(real);
+
+ return ret;
+}
+
const struct file_operations ovl_file_operations = {
.open = ovl_open,
.release = ovl_release,
.llseek = ovl_llseek,
.read_iter = ovl_read_iter,
.write_iter = ovl_write_iter,
+ .fsync = ovl_fsync,
};
--
2.14.3
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