mdadm -E /dev/sda --dump=foo
Creates a sparse file image of /dev/sda named foo with a copy of the
metadata instance found by -E.
When used in the opposite direction:
mdadm -E foo --dump=/dev/sda
...can restore metadata to a given block device, assuming it is
identical size to the dump file.
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
Examine.c | 42 ++++++++++++++++++++++++++++++++++++++++--
ReadMe.c | 1 +
mdadm.8.in | 13 +++++++++++++
mdadm.c | 11 ++++++++++-
mdadm.h | 3 ++-
5 files changed, 66 insertions(+), 4 deletions(-)
diff --git a/Examine.c b/Examine.c
index 5d71e53..ac5f36e 100644
--- a/Examine.c
+++ b/Examine.c
@@ -32,7 +32,7 @@
#include "md_p.h"
int Examine(struct mddev_dev *devlist, int brief, int export, int scan,
int SparcAdjust, struct supertype *forcest,
- char *homehost)
+ char *homehost, char *dump)
{
/* Read the raid superblock from a device and
@@ -50,7 +50,8 @@ int Examine(struct mddev_dev *devlist, int brief, int export, int scan,
* If (brief) gather devices for same array and just print a mdadm.conf line including devices=
* if devlist==NULL, use conf_get_devs()
*/
- int fd;
+ unsigned long long size = 0;
+ int fd, dfd;
int rv = 0;
int err = 0;
@@ -107,6 +108,8 @@ int Examine(struct mddev_dev *devlist, int brief, int export, int scan,
}
err = 1;
}
+ if (dump)
+ get_dev_size(fd, devlist->devname, &size);
close(fd);
}
if (err)
@@ -117,6 +120,41 @@ int Examine(struct mddev_dev *devlist, int brief, int export, int scan,
devlist->devname, 0, 0, NULL);
/* Ok, its good enough to try, though the checksum could be wrong */
+ if (dump && (have_container || !size)) {
+ fprintf(stderr, Name ": cannot get source device size\n");
+ break;
+ }
+
+ if (dump) {
+ struct stat s;
+
+ rv = 1;
+ dfd = open(dump, O_RDWR|O_CREAT|O_EXCL, S_IRUSR|S_IWUSR);
+ if (dfd < 0 && errno == EEXIST) {
+ if (ask("dump file exists, overwrite? "))
+ dfd = open(dump, O_RDWR, S_IRUSR|S_IWUSR);
+ }
+ if (dfd < 0) {
+ fprintf(stderr, Name ": failed to open %s: %s\n",
+ dump, strerror(errno));
+ break;
+ }
+
+ if (fstat(dfd, &s) != -1 && S_ISREG(s.st_mode)) {
+ if (ftruncate(dfd, size) < 0) {
+ fprintf(stderr, Name ": failed to setup dump file %s: %s\n",
+ dump, strerror(errno));
+ break;
+ }
+ }
+
+ rv = st->ss->store_super(st, dfd);
+ if (rv)
+ fprintf(stderr, Name ": failed to store metadata to %s: %s\n",
+ dump, strerror(errno));
+ break;
+ }
+
if (brief && st->ss->brief_examine_super == NULL) {
if (!scan)
fprintf(stderr, Name ": No brief listing for %s on %s\n",
diff --git a/ReadMe.c b/ReadMe.c
index b658841..684fbc9 100644
--- a/ReadMe.c
+++ b/ReadMe.c
@@ -169,6 +169,7 @@ struct option long_options[] = {
/* For Detail/Examine */
{"brief", 0, 0, Brief},
+ {"dump", 1, 0, Dump},
{"export", 0, 0, 'Y'},
{"sparc2.2", 0, 0, Sparc22},
{"test", 0, 0, 't'},
diff --git a/mdadm.8.in b/mdadm.8.in
index e22fde4..6eb65c3 100644
--- a/mdadm.8.in
+++ b/mdadm.8.in
@@ -1283,6 +1283,19 @@ device (e.g.
does not report the bitmap for that array.
.TP
+.BR \-\-dump
+Augment
+.B \-\-examine
+to, instead of printing the contents of the metadata, write the
+metadata image to the specified <file> argument. The <file> argument
+can be another block device or a regular file. In the case of a regular
+file the dump file will be created as a sparse file of equal size to the
+source of the metadata image. Note, this is a raw debug feature no
+attempt is made to check the validity of writing a given metadata image
+to a given block device. This assumes that only a single device is passed to
+.B \-\-examine.
+
+.TP
.BR \-R ", " \-\-run
start a partially assembled array. If
.B \-\-assemble
diff --git a/mdadm.c b/mdadm.c
index fb51051..154e116 100644
--- a/mdadm.c
+++ b/mdadm.c
@@ -106,6 +106,7 @@ int main(int argc, char *argv[])
char *subarray = NULL;
char *remove_path = NULL;
char *udev_filename = NULL;
+ char *dump_filename = NULL;
int print_help = 0;
FILE *outf;
@@ -160,6 +161,9 @@ int main(int argc, char *argv[])
case Brief:
brief = 1;
continue;
+ case Dump:
+ dump_filename = optarg;
+ continue;
case 'Y': export++;
continue;
@@ -1400,11 +1404,16 @@ int main(int argc, char *argv[])
fprintf(stderr, Name ": No devices listed in %s\n", configfile?configfile:DefaultConfFile);
exit(1);
}
+ if (dump_filename && (devs_found > 1 || scan)) {
+ fprintf(stderr,
+ Name ": Only one device can be specifed with --dump\n");
+ exit(2);
+ }
if (brief && verbose)
brief = 2;
rv = Examine(devlist, scan?(verbose>1?0:verbose+1):brief,
export, scan,
- SparcAdjust, ss, homehost);
+ SparcAdjust, ss, homehost, dump_filename);
} else if (devmode == DetailPlatform) {
rv = Detail_Platform(ss ? ss->ss : NULL, ss ? scan : 1, verbose);
} else {
diff --git a/mdadm.h b/mdadm.h
index 8bd0077..f242223 100644
--- a/mdadm.h
+++ b/mdadm.h
@@ -313,6 +313,7 @@ enum special_options {
RebuildMapOpt,
InvalidBackup,
UdevRules,
+ Dump,
};
/* structures read from config file */
@@ -1049,7 +1050,7 @@ extern int Detail(char *dev, int brief, int export, int test, char *homehost);
extern int Detail_Platform(struct superswitch *ss, int scan, int verbose);
extern int Query(char *dev);
extern int Examine(struct mddev_dev *devlist, int brief, int export, int scan,
- int SparcAdjust, struct supertype *forcest, char *homehost);
+ int SparcAdjust, struct supertype *forcest, char *homehost, char *dump);
extern int Monitor(struct mddev_dev *devlist,
char *mailaddr, char *alert_cmd,
int period, int daemonise, int scan, int oneshot,
--
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