On 2018年03月03日 02:47, je...@suse.com wrote:
> From: Jeff Mahoney <je...@suse.com>
>
> One of the common requests I receive is for 'df' like facilities
> for subvolume usage. Really, the request is for monitoring tools to be
> able to understand when subvolumes may be approaching quota in the same
> manner traditional file systems approach ENOSPC.
>
> This patch allows us to export the qgroups data in a machine-readable
> format so that monitoring tools can parse it easily.
>
> There are two modes since JSON can technically handle 64-bit numbers
> but JavaScript proper cannot. show -j enables JSON mode using 64-bit
> integers directly. --json-compat presents 64-bit numbers as an array
> of two 32-bit numbers (high followed by low).
>
> Signed-off-by: Jeff Mahoney <je...@suse.com>
> ---
> Documentation/btrfs-qgroup.asciidoc | 4 +
> Makefile.inc.in | 4 +-
> cmds-qgroup.c | 36 +++++-
> configure.ac | 6 +
> qgroup.c | 211
> ++++++++++++++++++++++++++++++++++++
> qgroup.h | 3 +
> 6 files changed, 258 insertions(+), 6 deletions(-)
>
> diff --git a/Documentation/btrfs-qgroup.asciidoc
> b/Documentation/btrfs-qgroup.asciidoc
> index 360b3269..22a9c2a7 100644
> --- a/Documentation/btrfs-qgroup.asciidoc
> +++ b/Documentation/btrfs-qgroup.asciidoc
> @@ -105,6 +105,10 @@ list all qgroups which impact the given path(include
> ancestral qgroups)
> list all qgroups which impact the given path(exclude ancestral qgroups)
> -v::::
> Be more verbose. Print pathnames of member qgroups when nested.
> +-j::::
> +If enabled, export qgroup usage information in JSON format. This implies
> --raw.
> +--json-compat::::
> +By default, JSON output contains full 64-bit integers, which may be
> incompatible with some JSON parsers. This option exports those values as an
> array of 32-bit numbers in [high, low] format.
> --raw::::
> raw numbers in bytes, without the 'B' suffix.
> --human-readable::::
> diff --git a/Makefile.inc.in b/Makefile.inc.in
> index 56271903..68bddbed 100644
> --- a/Makefile.inc.in
> +++ b/Makefile.inc.in
> @@ -18,9 +18,9 @@ BTRFSRESTORE_ZSTD = @BTRFSRESTORE_ZSTD@
> SUBST_CFLAGS = @CFLAGS@
> SUBST_LDFLAGS = @LDFLAGS@
>
> -LIBS_BASE = @UUID_LIBS@ @BLKID_LIBS@ -L. -pthread
> +LIBS_BASE = @UUID_LIBS@ @BLKID_LIBS@ @JSON_LIBS@ -L. -pthread
> LIBS_COMP = @ZLIB_LIBS@ @LZO2_LIBS@ @ZSTD_LIBS@
> -STATIC_LIBS_BASE = @UUID_LIBS_STATIC@ @BLKID_LIBS_STATIC@ -L. -pthread
> +STATIC_LIBS_BASE = @UUID_LIBS_STATIC@ @BLKID_LIBS_STATIC@ @JSON_LIBS_STATIC@
> -L. -pthread
> STATIC_LIBS_COMP = @ZLIB_LIBS_STATIC@ @LZO2_LIBS_STATIC@ @ZSTD_LIBS_STATIC@
>
> prefix ?= @prefix@
> diff --git a/cmds-qgroup.c b/cmds-qgroup.c
> index 94cd0fd3..eee15ef1 100644
> --- a/cmds-qgroup.c
> +++ b/cmds-qgroup.c
> @@ -282,6 +282,10 @@ static const char * const cmd_qgroup_show_usage[] = {
> " (excluding ancestral qgroups)",
> "-P print first-level qgroups using pathname",
> "-v verbose, prints all nested subvolumes",
> +#ifdef HAVE_JSON
> + "-j export in JSON format",
> + "--json-compat export in JSON compatibility mode",
> +#endif
> HELPINFO_UNITS_LONG,
> "--sort=qgroupid,rfer,excl,max_rfer,max_excl,pathname",
> " list qgroups sorted by specified items",
> @@ -302,6 +306,8 @@ static int cmd_qgroup_show(int argc, char **argv)
> unsigned unit_mode;
> int sync = 0;
> bool verbose = false;
> + bool export_json = false;
> + bool compat_json = false;
>
> struct btrfs_qgroup_comparer_set *comparer_set;
> struct btrfs_qgroup_filter_set *filter_set;
> @@ -314,16 +320,26 @@ static int cmd_qgroup_show(int argc, char **argv)
> int c;
> enum {
> GETOPT_VAL_SORT = 256,
> - GETOPT_VAL_SYNC
> + GETOPT_VAL_SYNC,
> + GETOPT_VAL_JSCOMPAT,
> };
> static const struct option long_options[] = {
> {"sort", required_argument, NULL, GETOPT_VAL_SORT},
> {"sync", no_argument, NULL, GETOPT_VAL_SYNC},
> {"verbose", no_argument, NULL, 'v'},
> +#ifdef HAVE_JSON
> + {"json-compat", no_argument, NULL, GETOPT_VAL_JSCOMPAT},
> +#endif
> { NULL, 0, NULL, 0 }
> };
> -
> - c = getopt_long(argc, argv, "pPcreFfv", long_options, NULL);
> + const char getopt_chars[] = {
> + 'p', 'P', 'c', 'r', 'e', 'F', 'f', 'v',
> +#ifdef HAVE_JSON
> + 'j',
> +#endif
> + '\0' };
> +
> + c = getopt_long(argc, argv, getopt_chars, long_options, NULL);
> if (c < 0)
> break;
> switch (c) {
> @@ -353,6 +369,14 @@ static int cmd_qgroup_show(int argc, char **argv)
> case 'f':
> filter_flag |= 0x2;
> break;
> +#ifdef HAVE_JSON
> + case GETOPT_VAL_JSCOMPAT:
> + compat_json = true;
> + case 'j':
> + unit_mode = UNITS_RAW;
> + export_json = true;
> + break;
> +#endif
> case GETOPT_VAL_SORT:
> ret = btrfs_qgroup_parse_sort_string(optarg,
> &comparer_set);
> @@ -405,7 +429,11 @@ static int cmd_qgroup_show(int argc, char **argv)
> BTRFS_QGROUP_FILTER_PARENT,
> qgroupid);
> }
> - ret = btrfs_show_qgroups(fd, filter_set, comparer_set, verbose);
> + if (export_json)
> + ret = btrfs_export_qgroups_json(fd, filter_set, comparer_set,
> + compat_json);
> + else
> + ret = btrfs_show_qgroups(fd, filter_set, comparer_set, verbose);
> close_file_or_dir(fd, dirstream);
> free(filter_set);
> free(comparer_set);
> diff --git a/configure.ac b/configure.ac
> index 56d17c3a..6aec672a 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -197,6 +197,12 @@ PKG_STATIC(UUID_LIBS_STATIC, [uuid])
> PKG_CHECK_MODULES(ZLIB, [zlib])
> PKG_STATIC(ZLIB_LIBS_STATIC, [zlib])
>
> +PKG_CHECK_MODULES(JSON, [json-c], [
Json-c is quite common and also used by cryptsetup, so pretty good
library choice.
> + AC_DEFINE(HAVE_JSON, [1], [Have JSON]),
> + PKG_STATIC(JSON_LIBS_STATIC, [json-c], [
> + AC_DEFINE(HAVE_JSON_STATIC, [1], [Have JSON static])], [true])
> + ], [true])
> +
> AC_ARG_ENABLE([zstd],
> AS_HELP_STRING([--disable-zstd], [build without zstd support]),
> [], [enable_zstd=yes]
> diff --git a/qgroup.c b/qgroup.c
> index 2d0a6947..f632a45c 100644
> --- a/qgroup.c
> +++ b/qgroup.c
> @@ -16,12 +16,16 @@
> * Boston, MA 021110-1307, USA.
> */
>
> +#include "version.h"
> #include "qgroup.h"
> #include <sys/ioctl.h>
> #include "ctree.h"
> #include "ioctl.h"
> #include "utils.h"
> #include <errno.h>
> +#ifdef HAVE_JSON
> +#include <json-c/json.h>
> +#endif
>
> #define BTRFS_QGROUP_NFILTERS_INCREASE (2 * BTRFS_QGROUP_FILTER_MAX)
> #define BTRFS_QGROUP_NCOMPS_INCREASE (2 * BTRFS_QGROUP_COMP_MAX)
> @@ -1346,6 +1350,213 @@ int btrfs_show_qgroups(int fd,
> return ret;
> }
>
> +#ifdef HAVE_JSON
> +static void format_qgroupid(char *buf, size_t size, u64 qgroupid)
> +{
> + int ret;
> +
> + ret = snprintf(buf, size, "%llu/%llu",
> + btrfs_qgroup_level(qgroupid),
> + btrfs_qgroup_subvid(qgroupid));
> + ASSERT(ret < sizeof(buf));
This is designed to catch truncated snprintf(), right?
This can be addressed by setting up the @buf properly.
(See below)
And in fact, due to that super magic number, we won't hit this ASSERT()
anyway.
> +}
> +
> +static json_object *export_one_u64(u64 value, bool compat)
> +{
> + json_object *array, *tmp;
> +
> + if (!compat)
> + return json_object_new_int64(value);
> +
> + array = json_object_new_array();
> + if (!array)
> + return NULL;
> +
> + tmp = json_object_new_int(value >> 32);
> + if (!tmp)
> + goto failure;
> + json_object_array_add(array, tmp);
> +
> + tmp = json_object_new_int(value & 0xffffffff);
> + if (!tmp)
> + goto failure;
> + json_object_array_add(array, tmp);
> +
> + return array;
> +failure:
> + json_object_put(array);
> + return NULL;
> +}
> +
> +static bool export_one_qgroup(json_object *container,
> + const struct btrfs_qgroup *qgroup, bool compat)
> +{
> + json_object *obj = json_object_new_object();
> + json_object *tmp;
> + char buf[42];
Answer to the ultimate question of life, the universe, and everything. :)
Although according to the format level/subvolid, it should be
count_digits(MAX_U16) + 1 + count_digits(MAX_U48) + 1. (1 for '/' and 1
for '\n')
Could be defined as a macro as:
#define QGROUP_FORMAT_BUF_LEN (count_digits(1ULL<<16) + 1 + \
count_digits(1ULL<<48) + 1)
BTW, the result is just 22.
Despite that looks good.
Thanks,
Qu
> +
> + format_qgroupid(buf, sizeof(buf), qgroup->qgroupid);
> + tmp = json_object_new_string(buf);
> + if (!tmp)
> + return false;
> + json_object_object_add(obj, "qgroupid", tmp);
> +
> + tmp = export_one_u64(qgroup->qgroupid, compat);
> + if (!tmp)
> + goto failure;
> + json_object_object_add(obj, "qgroupid_raw", tmp);> +
> + tmp = export_one_u64(qgroup->info.generation, compat);
> + if (!tmp)
> + goto failure;
> + json_object_object_add(obj, "generation", tmp);
> +
> + tmp = export_one_u64(qgroup->info.referenced, compat);
> + if (!tmp)
> + goto failure;
> + json_object_object_add(obj, "referenced_bytes", tmp);
> +
> + tmp = export_one_u64(qgroup->info.exclusive, compat);
> + if (!tmp)
> + goto failure;
> + json_object_object_add(obj, "exclusive_bytes", tmp);
> +
> + tmp = export_one_u64(qgroup->limit.max_referenced, compat);
> + if (!tmp)
> + goto failure;
> + json_object_object_add(obj, "referenced_limit_bytes", tmp);
> +
> + tmp = export_one_u64(qgroup->limit.max_exclusive, compat);
> + if (!tmp)
> + goto failure;
> + json_object_object_add(obj, "exclusive_limit_bytes", tmp);
> +
> + if (btrfs_qgroup_level(qgroup->qgroupid) == 0) {
> + tmp = json_object_new_string(qgroup->pathname);
> + if (!tmp)
> + goto failure;
> + json_object_object_add(obj, "pathname", tmp);
> + } else {
> + json_object *array = json_object_new_array();
> + struct btrfs_qgroup_list *list = NULL;
> + if (!array)
> + goto failure;
> + json_object_object_add(obj, "members", array);
> +
> + list_for_each_entry(list, &qgroup->qgroups, next_qgroup) {
> + struct btrfs_qgroup *member = list->qgroup;
> + char buf2[42];
> +
> + format_qgroupid(buf2, sizeof(buf2), member->qgroupid);
> + tmp = json_object_new_string(buf2);
> + if (!tmp)
> + goto failure;
> +
> + json_object_array_add(array, tmp);
> + }
> + }
> +
> + json_object_object_add(container, buf, obj);
> + return true;
> +failure:
> + json_object_put(obj);
> + return false;
> +}
> +
> +#define BTRFS_JSON_WARNING \
> +"This data contains 64-bit values that are incompatible with Javascript.
> Export in compatibility mode using --json-compat."
> +
> +static void export_all_qgroups(const struct qgroup_lookup *qgroup_lookup,
> + bool compat)
> +{
> +
> + struct rb_node *n;
> + const char *json;
> + json_object *container, *dict, *obj;
> + struct btrfs_qgroup *entry;
> +
> + container = json_object_new_object();
> + if (!container)
> + goto failure_msg;
> +
> + obj = json_object_new_string(BTRFS_BUILD_VERSION);
> + if (!obj)
> + goto failure;
> + json_object_object_add(container, "exporter", obj);
> +
> + if (!compat) {
> + obj = json_object_new_string(BTRFS_JSON_WARNING);
> + if (!obj)
> + goto failure;
> + json_object_object_add(container, "compatibility-warning", obj);
> +
> + obj = json_object_new_string("64-bit");
> + if (!obj)
> + goto failure;
> + json_object_object_add(container, "u64-format", obj);
> + } else {
> + obj = json_object_new_string("array");
> + if (!obj)
> + goto failure;
> + json_object_object_add(container, "u64-format", obj);
> + }
> +
> + dict = json_object_new_object();
> + if (!dict)
> + goto failure;
> + json_object_object_add(container, "qgroup_data", dict);
> +
> + n = rb_first(&qgroup_lookup->root);
> + while (n) {
> + entry = rb_entry(n, struct btrfs_qgroup, sort_node);
> + if (!export_one_qgroup(dict, entry, compat))
> + goto failure;
> + n = rb_next(n);
> + }
> +
> + json = json_object_to_json_string(container);
> + if (!json)
> + goto failure;
> +
> + puts(json);
> +
> + /* clean up container */
> + json_object_put(container);
> + return;
> +
> +failure:
> + json_object_put(container);
> +failure_msg:
> + error("Failed to create JSON object.");
> +}
> +#endif
> +
> +int btrfs_export_qgroups_json(int fd,
> + struct btrfs_qgroup_filter_set *filter_set,
> + struct btrfs_qgroup_comparer_set *comp_set,
> + bool compat)
> +{
> +
> +#ifdef HAVE_JSON
> + struct qgroup_lookup qgroup_lookup;
> + struct qgroup_lookup sort_tree;
> + int ret = 0;
> +
> + ret = qgroups_search_all(fd, &qgroup_lookup);
> + if (ret)
> + return ret;
> + __filter_and_sort_qgroups(&qgroup_lookup, &sort_tree,
> + filter_set, comp_set);
> + export_all_qgroups(&sort_tree, compat);
> +
> + __free_all_qgroups(&qgroup_lookup);
> +
> + return ret;
> +#else
> + return 0;
> +#endif
> +}
> +
> int btrfs_qgroup_parse_sort_string(const char *opt_arg,
> struct btrfs_qgroup_comparer_set **comps)
> {
> diff --git a/qgroup.h b/qgroup.h
> index 688f92b2..2883727b 100644
> --- a/qgroup.h
> +++ b/qgroup.h
> @@ -97,6 +97,9 @@ int btrfs_qgroup_parse_sort_string(const char *opt_arg,
> struct btrfs_qgroup_comparer_set **comps);
> int btrfs_show_qgroups(int fd, struct btrfs_qgroup_filter_set *,
> struct btrfs_qgroup_comparer_set *, bool verbose);
> +int btrfs_export_qgroups_json(int fd, struct btrfs_qgroup_filter_set *,
> + struct btrfs_qgroup_comparer_set *,
> + bool compat);
> void btrfs_qgroup_setup_print_column(enum btrfs_qgroup_column_enum column);
> void btrfs_qgroup_setup_units(unsigned unit_mode);
> struct btrfs_qgroup_filter_set *btrfs_qgroup_alloc_filter_set(void);
>
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