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Add zdb -r <dataset> <object-id | file> <output>

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While you can use zdb -R poolname vdev:offset:[<lsize>/]<psize>[:flags] 
to extract individual DVAs from a vdev, it would be handy for be able 
copy an entire file out of the pool.

Given a file or object number, add support to copy the contents to a 
file. Useful for debugging and recovery.

Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Allan Jude <allan@klarasystems.com>
Closes #11027
This commit is contained in:
Allan Jude
2021-01-28 00:36:01 -05:00
committed by GitHub
parent b2c5904a78
commit 393e69241e
7 changed files with 240 additions and 15 deletions
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cmd/zdb/zdb.c
+106 -11
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@@ -31,6 +31,7 @@
*
* [1] Portions of this software were developed by Allan Jude
* under sponsorship from the FreeBSD Foundation.
* Copyright (c) 2021 Allan Jude
*/
#include <stdio.h>
@@ -755,13 +756,14 @@ usage(void)
"\t%s -m [-AFLPX] [-e [-V] [-p <path> ...]] [-t <txg>] "
"[-U <cache>]\n\t\t<poolname> [<vdev> [<metaslab> ...]]\n"
"\t%s -O <dataset> <path>\n"
"\t%s -r <dataset> <path> <destination>\n"
"\t%s -R [-A] [-e [-V] [-p <path> ...]] [-U <cache>]\n"
"\t\t<poolname> <vdev>:<offset>:<size>[:<flags>]\n"
"\t%s -E [-A] word0:word1:...:word15\n"
"\t%s -S [-AP] [-e [-V] [-p <path> ...]] [-U <cache>] "
"<poolname>\n\n",
cmdname, cmdname, cmdname, cmdname, cmdname, cmdname, cmdname,
cmdname, cmdname, cmdname);
cmdname, cmdname, cmdname, cmdname);
(void) fprintf(stderr, " Dataset name must include at least one "
"separator character '/' or '@'\n");
@@ -800,6 +802,7 @@ usage(void)
(void) fprintf(stderr, " -m metaslabs\n");
(void) fprintf(stderr, " -M metaslab groups\n");
(void) fprintf(stderr, " -O perform object lookups by path\n");
(void) fprintf(stderr, " -r copy an object by path to file\n");
(void) fprintf(stderr, " -R read and display block from a "
"device\n");
(void) fprintf(stderr, " -s report stats on zdb's I/O\n");
@@ -4490,7 +4493,7 @@ static char curpath[PATH_MAX];
* for the last one.
*/
static int
dump_path_impl(objset_t *os, uint64_t obj, char *name)
dump_path_impl(objset_t *os, uint64_t obj, char *name, uint64_t *retobj)
{
int err;
boolean_t header = B_TRUE;
@@ -4540,10 +4543,15 @@ dump_path_impl(objset_t *os, uint64_t obj, char *name)
switch (doi.doi_type) {
case DMU_OT_DIRECTORY_CONTENTS:
if (s != NULL && *(s + 1) != '\0')
return (dump_path_impl(os, child_obj, s + 1));
return (dump_path_impl(os, child_obj, s + 1, retobj));
/*FALLTHROUGH*/
case DMU_OT_PLAIN_FILE_CONTENTS:
dump_object(os, child_obj, dump_opt['v'], &header, NULL, 0);
if (retobj != NULL) {
*retobj = child_obj;
} else {
dump_object(os, child_obj, dump_opt['v'], &header,
NULL, 0);
}
return (0);
default:
(void) fprintf(stderr, "object %llu has non-file/directory "
@@ -4558,7 +4566,7 @@ dump_path_impl(objset_t *os, uint64_t obj, char *name)
* Dump the blocks for the object specified by path inside the dataset.
*/
static int
dump_path(char *ds, char *path)
dump_path(char *ds, char *path, uint64_t *retobj)
{
int err;
objset_t *os;
@@ -4578,12 +4586,89 @@ dump_path(char *ds, char *path)
(void) snprintf(curpath, sizeof (curpath), "dataset=%s path=/", ds);
err = dump_path_impl(os, root_obj, path);
err = dump_path_impl(os, root_obj, path, retobj);
close_objset(os, FTAG);
return (err);
}
static int
zdb_copy_object(objset_t *os, uint64_t srcobj, char *destfile)
{
int err = 0;
uint64_t size, readsize, oursize, offset;
ssize_t writesize;
sa_handle_t *hdl;
(void) printf("Copying object %" PRIu64 " to file %s\n", srcobj,
destfile);
VERIFY3P(os, ==, sa_os);
if ((err = sa_handle_get(os, srcobj, NULL, SA_HDL_PRIVATE, &hdl))) {
(void) printf("Failed to get handle for SA znode\n");
return (err);
}
if ((err = sa_lookup(hdl, sa_attr_table[ZPL_SIZE], &size, 8))) {
(void) sa_handle_destroy(hdl);
return (err);
}
(void) sa_handle_destroy(hdl);
(void) printf("Object %" PRIu64 " is %" PRIu64 " bytes\n", srcobj,
size);
if (size == 0) {
return (EINVAL);
}
int fd = open(destfile, O_WRONLY | O_CREAT | O_TRUNC, 0644);
/*
* We cap the size at 1 mebibyte here to prevent
* allocation failures and nigh-infinite printing if the
* object is extremely large.
*/
oursize = MIN(size, 1 << 20);
offset = 0;
char *buf = kmem_alloc(oursize, KM_NOSLEEP);
if (buf == NULL) {
return (ENOMEM);
}
while (offset < size) {
readsize = MIN(size - offset, 1 << 20);
err = dmu_read(os, srcobj, offset, readsize, buf, 0);
if (err != 0) {
(void) printf("got error %u from dmu_read\n", err);
kmem_free(buf, oursize);
return (err);
}
if (dump_opt['v'] > 3) {
(void) printf("Read offset=%" PRIu64 " size=%" PRIu64
" error=%d\n", offset, readsize, err);
}
writesize = write(fd, buf, readsize);
if (writesize < 0) {
err = errno;
break;
} else if (writesize != readsize) {
/* Incomplete write */
(void) fprintf(stderr, "Short write, only wrote %llu of"
" %" PRIu64 " bytes, exiting...\n",
(u_longlong_t)writesize, readsize);
break;
}
offset += readsize;
}
(void) close(fd);
if (buf != NULL)
kmem_free(buf, oursize);
return (err);
}
static int
dump_label(const char *dev)
{
@@ -8167,6 +8252,7 @@ main(int argc, char **argv)
nvlist_t *policy = NULL;
uint64_t max_txg = UINT64_MAX;
int64_t objset_id = -1;
uint64_t object;
int flags = ZFS_IMPORT_MISSING_LOG;
int rewind = ZPOOL_NEVER_REWIND;
char *spa_config_path_env, *objset_str;
@@ -8195,7 +8281,7 @@ main(int argc, char **argv)
zfs_btree_verify_intensity = 3;
while ((c = getopt(argc, argv,
"AbcCdDeEFGhiI:klLmMo:Op:PqRsSt:uU:vVx:XYyZ")) != -1) {
"AbcCdDeEFGhiI:klLmMo:Op:PqrRsSt:uU:vVx:XYyZ")) != -1) {
switch (c) {
case 'b':
case 'c':
@@ -8210,6 +8296,7 @@ main(int argc, char **argv)
case 'm':
case 'M':
case 'O':
case 'r':
case 'R':
case 's':
case 'S':
@@ -8299,7 +8386,7 @@ main(int argc, char **argv)
(void) fprintf(stderr, "-p option requires use of -e\n");
usage();
}
if (dump_opt['d']) {
if (dump_opt['d'] || dump_opt['r']) {
/* <pool>[/<dataset | objset id> is accepted */
if (argv[2] && (objset_str = strchr(argv[2], '/')) != NULL &&
objset_str++ != NULL) {
@@ -8358,7 +8445,7 @@ main(int argc, char **argv)
verbose = MAX(verbose, 1);
for (c = 0; c < 256; c++) {
if (dump_all && strchr("AeEFklLOPRSXy", c) == NULL)
if (dump_all && strchr("AeEFklLOPrRSXy", c) == NULL)
dump_opt[c] = 1;
if (dump_opt[c])
dump_opt[c] += verbose;
@@ -8394,7 +8481,13 @@ main(int argc, char **argv)
if (argc != 2)
usage();
dump_opt['v'] = verbose + 3;
return (dump_path(argv[0], argv[1]));
return (dump_path(argv[0], argv[1], NULL));
}
if (dump_opt['r']) {
if (argc != 3)
usage();
dump_opt['v'] = verbose;
error = dump_path(argv[0], argv[1], &object);
}
if (dump_opt['X'] || dump_opt['F'])
@@ -8572,7 +8665,9 @@ main(int argc, char **argv)
argv++;
argc--;
if (!dump_opt['R']) {
if (dump_opt['r']) {
error = zdb_copy_object(os, object, argv[1]);
} else if (!dump_opt['R']) {
flagbits['d'] = ZOR_FLAG_DIRECTORY;
flagbits['f'] = ZOR_FLAG_PLAIN_FILE;
flagbits['m'] = ZOR_FLAG_SPACE_MAP;