Add new ReadFileWithVerify storage-layer API (#4349)

This is an enhancement to the XL/distributed-XL mode. FS mode is
unaffected.

The ReadFileWithVerify storage-layer call is similar to ReadFile with
the additional functionality of performing bit-rot checking. It
accepts additional parameters for a hashing algorithm to use and the
expected hex-encoded hash string.

This patch provides significant performance improvement because:

1. combines the step of reading the file (during
erasure-decoding/reconstruction) with bit-rot verification;

2. limits the number of file-reads; and

3. avoids transferring the file over the network for bit-rot
verification.

ReadFile API is implemented as ReadFileWithVerify with empty hashing
arguments.

Credits to AB and Harsha for the algorithmic improvement.

Fixes #4236.
This commit is contained in:
Aditya Manthramurthy
2017-05-16 14:21:52 -07:00
committed by Harshavardhana
parent cae4683971
commit 8975da4e84
20 changed files with 471 additions and 88 deletions

View File

@@ -122,6 +122,15 @@ func (d *naughtyDisk) ReadFile(volume string, path string, offset int64, buf []b
return d.disk.ReadFile(volume, path, offset, buf)
}
func (d *naughtyDisk) ReadFileWithVerify(volume, path string, offset int64,
buf []byte, algo HashAlgo, expectedHash string) (n int64, err error) {
if err := d.calcError(); err != nil {
return 0, err
}
return d.disk.ReadFileWithVerify(volume, path, offset, buf, algo, expectedHash)
}
func (d *naughtyDisk) PrepareFile(volume, path string, length int64) error {
if err := d.calcError(); err != nil {
return err