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Redacted send/receive allows users to send subsets of their data to a target system. One possible use case for this feature is to not transmit sensitive information to a data warehousing, test/dev, or analytics environment. Another is to save space by not replicating unimportant data within a given dataset, for example in backup tools like zrepl. Redacted send/receive is a three-stage process. First, a clone (or clones) is made of the snapshot to be sent to the target. In this clone (or clones), all unnecessary or unwanted data is removed or modified. This clone is then snapshotted to create the "redaction snapshot" (or snapshots). Second, the new zfs redact command is used to create a redaction bookmark. The redaction bookmark stores the list of blocks in a snapshot that were modified by the redaction snapshot(s). Finally, the redaction bookmark is passed as a parameter to zfs send. When sending to the snapshot that was redacted, the redaction bookmark is used to filter out blocks that contain sensitive or unwanted information, and those blocks are not included in the send stream. When sending from the redaction bookmark, the blocks it contains are considered as candidate blocks in addition to those blocks in the destination snapshot that were modified since the creation_txg of the redaction bookmark. This step is necessary to allow the target to rehydrate data in the case where some blocks are accidentally or unnecessarily modified in the redaction snapshot. The changes to bookmarks to enable fast space estimation involve adding deadlists to bookmarks. There is also logic to manage the life cycles of these deadlists. The new size estimation process operates in cases where previously an accurate estimate could not be provided. In those cases, a send is performed where no data blocks are read, reducing the runtime significantly and providing a byte-accurate size estimate. Reviewed-by: Dan Kimmel <dan.kimmel@delphix.com> Reviewed-by: Matt Ahrens <mahrens@delphix.com> Reviewed-by: Prashanth Sreenivasa <pks@delphix.com> Reviewed-by: John Kennedy <john.kennedy@delphix.com> Reviewed-by: George Wilson <george.wilson@delphix.com> Reviewed-by: Chris Williamson <chris.williamson@delphix.com> Reviewed-by: Pavel Zhakarov <pavel.zakharov@delphix.com> Reviewed-by: Sebastien Roy <sebastien.roy@delphix.com> Reviewed-by: Prakash Surya <prakash.surya@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Paul Dagnelie <pcd@delphix.com> Closes #7958
110 lines
2.7 KiB
C
110 lines
2.7 KiB
C
/*
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* This file and its contents are supplied under the terms of the
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* Common Development and Distribution License ("CDDL"), version 1.0.
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* You may only use this file in accordance with the terms of version
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* 1.0 of the CDDL.
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*
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* A full copy of the text of the CDDL should have accompanied this
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* source. A copy of the CDDL is also available via the Internet at
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* http://www.illumos.org/license/CDDL.
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*/
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/*
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* Copyright (c) 2018 by Delphix. All rights reserved.
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*/
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#include <stdio.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#include <assert.h>
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#include <sys/param.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <errno.h>
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static void
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usage(char *msg, int exit_value)
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{
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(void) fprintf(stderr, "get_diff file redacted_file\n");
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(void) fprintf(stderr, "%s\n", msg);
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exit(exit_value);
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}
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/*
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* This utility compares two files, an original and its redacted counterpart
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* (in that order). It compares the files 512 bytes at a time, printing out
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* any ranges (as offset and length) where the redacted file does not match
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* the original. This output is used to verify that the expected ranges of
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* a redacted file do not contain the original data.
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*/
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int
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main(int argc, char *argv[])
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{
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off_t diff_off = 0, diff_len = 0, off = 0;
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int fd1, fd2;
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char *fname1, *fname2;
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char buf1[DEV_BSIZE], buf2[DEV_BSIZE];
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ssize_t bytes;
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if (argc != 3)
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usage("Incorrect number of arguments.", 1);
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if ((fname1 = argv[1]) == NULL)
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usage("Filename missing.", 1);
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if ((fd1 = open(fname1, O_LARGEFILE | O_RDONLY)) < 0) {
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perror("open1 failed");
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exit(1);
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}
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if ((fname2 = argv[2]) == NULL)
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usage("Redacted filename missing.", 1);
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if ((fd2 = open(fname2, O_LARGEFILE | O_RDONLY)) < 0) {
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perror("open2 failed");
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exit(1);
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}
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while ((bytes = pread(fd1, buf1, DEV_BSIZE, off)) > 0) {
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if (pread(fd2, buf2, DEV_BSIZE, off) < 0) {
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if (errno == EIO) {
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/*
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* A read in a redacted section of a file will
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* fail with EIO. If we get EIO, continue on
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* but ensure that a comparison of buf1 and
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* buf2 will fail, indicating a redacted block.
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*/
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buf2[0] = ~buf1[0];
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} else {
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perror("pread failed");
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exit(1);
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}
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}
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if (memcmp(buf1, buf2, bytes) == 0) {
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if (diff_len != 0) {
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(void) fprintf(stdout, "%lld,%lld\n",
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(long long)diff_off, (long long)diff_len);
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assert(off == diff_off + diff_len);
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diff_len = 0;
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}
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diff_off = 0;
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} else {
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if (diff_len == 0)
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diff_off = off;
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assert(off == diff_off + diff_len);
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diff_len += bytes;
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}
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off += bytes;
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}
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if (diff_len != 0 && diff_len != 0) {
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(void) fprintf(stdout, "%lld,%lld\n", (long long)diff_off,
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(long long)diff_len);
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}
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(void) close(fd1);
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(void) close(fd2);
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return (0);
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}
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