[PATCH 2/2] btrfs-progs: use kernel for mounted and lblkid to scan disks

[PATCH 2/2] btrfs-progs: use kernel for mounted and lblkid to scan disks

[Anand Jain]

As of now btrfs filesystem show reads directly from
disks. So sometimes output can be stale, mainly when
user want to verify their last operation like,
labeling or device delete or add... etc. so this
patch will read from the kernel ioctl if it finds
that disk is mounted.

Further, to scan for the disks this patch will use
lblkid, so that we don't have to manually scan the
/dev or /dev/mapper which means we don't need the
--all-devices options.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
 cmds-device.c     |   21 +-----
 cmds-filesystem.c |  188 +++++++++++++++++++++++++++++++++++++++--------------
 utils.c           |   55 +++++++++++++++-
 utils.h           |    7 ++-
 4 files changed, 200 insertions(+), 71 deletions(-)

diff --git a/cmds-device.c b/cmds-device.c
index be2aaff..833ad30 100644
--- a/cmds-device.c
+++ b/cmds-device.c
@@ -186,7 +186,7 @@ static int cmd_rm_dev(int argc, char **argv)
 }
 
 static const char * const cmd_scan_dev_usage[] = {
-	"btrfs device scan [<--all-devices>|<device> [<device>...]]",
+	"btrfs device scan [<device>...]",
 	"Scan devices for a btrfs filesystem",
 	NULL
 };
@@ -194,28 +194,15 @@ static const char * const cmd_scan_dev_usage[] = {
 static int cmd_scan_dev(int argc, char **argv)
 {
 	int	i, fd, e;
-	int	where = BTRFS_SCAN_PROC;
 	int	devstart = 1;
 
-	if( argc > 1 && !strcmp(argv[1],"--all-devices")){
-		if (check_argc_max(argc, 2))
-			usage(cmd_scan_dev_usage);
-
-		where = BTRFS_SCAN_DEV;
-		devstart += 1;
-	}
-
-	if(argc<=devstart){
-		int ret;
+	if (argc <= devstart) {
 		printf("Scanning for Btrfs filesystems\n");
-		ret = scan_for_btrfs(where, 1);
-		if (ret){
-			fprintf(stderr, "ERROR: error %d while scanning\n", ret);
-			return 18;
-		}
+		scan_for_btrfs_v2(BTRFS_UPDATE_KERNEL);
 		return 0;
 	}
 
+	/* there are specific device/file to scan*/
 	fd = open("/dev/btrfs-control", O_RDWR);
 	if (fd < 0) {
 		perror("failed to open /dev/btrfs-control");
diff --git a/cmds-filesystem.c b/cmds-filesystem.c
index 890d8fd..412f793 100644
--- a/cmds-filesystem.c
+++ b/cmds-filesystem.c
@@ -22,6 +22,9 @@
 #include <errno.h>
 #include <uuid/uuid.h>
 #include <ctype.h>
+#include <mntent.h>
+#include <fcntl.h>
+#include <linux/limits.h>
 
 #include "kerncompat.h"
 #include "ctree.h"
@@ -173,27 +176,6 @@ static int cmd_df(int argc, char **argv)
 	return ret;
 }
 
-static int uuid_search(struct btrfs_fs_devices *fs_devices, char *search)
-{
-	char uuidbuf[37];
-	struct list_head *cur;
-	struct btrfs_device *device;
-	int search_len = strlen(search);
-
-	search_len = min(search_len, 37);
-	uuid_unparse(fs_devices->fsid, uuidbuf);
-	if (!strncmp(uuidbuf, search, search_len))
-		return 1;
-
-	list_for_each(cur, &fs_devices->devices) {
-		device = list_entry(cur, struct btrfs_device, dev_list);
-		if ((device->label && strcmp(device->label, search) == 0) ||
-		    strcmp(device->name, search) == 0)
-			return 1;
-	}
-	return 0;
-}
-
 static void print_one_uuid(struct btrfs_fs_devices *fs_devices)
 {
 	char uuidbuf[37];
@@ -210,10 +192,10 @@ static void print_one_uuid(struct btrfs_fs_devices *fs_devices)
 	else
 		printf("Label: none ");
 
-
 	total = device->total_devs;
-	printf(" uuid: %s\n\tTotal devices %llu FS bytes used %s\n", uuidbuf,
-	       (unsigned long long)total,
+
+	printf(" uuid: %s (unmounted)\n\tTotal devices %llu FS bytes used %s\n",
+		uuidbuf, (unsigned long long)total,
 	       pretty_size(device->super_bytes_used));
 
 	list_for_each(cur, &fs_devices->devices) {
@@ -232,8 +214,108 @@ static void print_one_uuid(struct btrfs_fs_devices *fs_devices)
 	printf("\n");
 }
 
+/* adds up all the used spaces as reported by the space info ioctl
+ */
+static u64 cal_used_bytes(struct btrfs_ioctl_space_args *si)
+{
+	u64 ret = 0;
+	int i;
+	for (i = 0; i < si->total_spaces; i++)
+		ret += si->spaces[i].used_bytes;
+	return ret;
+}
+
+static int print_one_fs(struct btrfs_ioctl_fs_info_args *fi,
+		struct btrfs_ioctl_dev_info_args *di_n,
+		struct btrfs_ioctl_space_args *si_n, char *label, char *path)
+{
+	int i;
+	char uuidbuf[37];
+	struct btrfs_ioctl_dev_info_args *di = di_n;
+	u64 flags;
+
+	uuid_unparse(fi->fsid, uuidbuf);
+	printf("Label: %s  uuid: %s mounted: %s\n",
+		strlen(label) ? label : "none", uuidbuf, path);
+	printf("\tGroup profile:");
+	for (i = si_n->total_spaces - 1; i >= 0; i--) {
+		flags = si_n->spaces[i].flags;
+		if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
+			continue;
+		printf(" %s: %s", group_type_str(flags),
+					group_profile_str(flags));
+		printf(" ");
+	}
+	printf("\n");
+
+	printf("\tTotal devices %llu FS bytes used %s\n",
+				fi->num_devices,
+			pretty_size(cal_used_bytes(si_n)));
+
+	for (i = 0; i < fi->num_devices; i++) {
+		di = (struct btrfs_ioctl_dev_info_args *)&di_n[i];
+		printf("\tdevid    %llu size %s used %s path %s\n",
+			di->devid,
+			pretty_size(di->total_bytes),
+			pretty_size(di->bytes_used),
+			di->path);
+	}
+
+	printf("\n");
+	return 0;
+}
+
+static int btrfs_scan_kernel(void *input, int type)
+{
+	int ret = 0, fd;
+	FILE *f;
+	struct mntent *mnt;
+	struct btrfs_ioctl_fs_info_args fi;
+	struct btrfs_ioctl_dev_info_args *di = NULL;
+	struct btrfs_ioctl_space_args *si;
+	char label[BTRFS_LABEL_SIZE];
+
+	f = setmntent("/proc/mounts", "r");
+	if (f == NULL)
+		return -errno;
+
+	while ((mnt = getmntent(f)) != NULL) {
+		if (strcmp(mnt->mnt_type, "btrfs"))
+			continue;
+		ret = get_fs_info(mnt->mnt_dir, &fi, &di);
+		if (ret)
+			return ret;
+
+		switch (type) {
+		case 0:
+			break;
+		case 1:
+			if (uuid_compare(fi.fsid, (u8 *)input))
+				continue;
+			break;
+		case 2:
+			if (strcmp(input, mnt->mnt_dir))
+				continue;
+			break;
+		default:
+			break;
+		}
+
+		fd = open(mnt->mnt_dir, O_RDONLY);
+		if (fd > 0 && !get_df(fd, &si)) {
+			get_label_mounted(mnt->mnt_dir, label);
+			print_one_fs(&fi, di, si, label, mnt->mnt_dir);
+			free(si);
+		}
+		if (fd > 0)
+			close(fd);
+		free(di);
+	}
+	return ret;
+}
+
 static const char * const cmd_show_usage[] = {
-	"btrfs filesystem show [--all-devices|<uuid>]",
+	"btrfs filesystem show [--mounted]",
 	"Show the structure of a filesystem",
 	"If no argument is given, structure of all present filesystems is shown.",
 	NULL
@@ -244,36 +326,42 @@ static int cmd_show(int argc, char **argv)
 	struct list_head *all_uuids;
 	struct btrfs_fs_devices *fs_devices;
 	struct list_head *cur_uuid;
-	char *search = 0;
-	int ret;
-	int where = BTRFS_SCAN_PROC;
-	int searchstart = 1;
-
-	if( argc > 1 && !strcmp(argv[1],"--all-devices")){
-		where = BTRFS_SCAN_DEV;
-		searchstart += 1;
-	}
+	int ret = 0;
+	int where = 0;
 
-	if (check_argc_max(argc, searchstart + 1))
+	if (check_argc_max(argc, 2))
 		usage(cmd_show_usage);
 
-	ret = scan_for_btrfs(where, 0);
-
-	if (ret){
-		fprintf(stderr, "ERROR: error %d while scanning\n", ret);
-		return 18;
-	}
-	
-	if(searchstart < argc)
-		search = argv[searchstart];
+	/* show only mounted btrfs disks */
+	if (argc > 1 && !strcmp(argv[1], "--mounted"))
+		where = BTRFS_SCAN_MOUNTED;
 
-	all_uuids = btrfs_scanned_uuids();
-	list_for_each(cur_uuid, all_uuids) {
-		fs_devices = list_entry(cur_uuid, struct btrfs_fs_devices,
+	switch (where) {
+	case 0:
+		/* no option : show both mounted and unmounted
+		 */
+		/* mounted */
+		ret = btrfs_scan_kernel(NULL, 0);
+		if (ret)
+			fprintf(stderr, "ERROR: scan kernel failed, %d\n",
+				ret);
+
+		/* unmounted */
+		scan_for_btrfs_v2(!BTRFS_UPDATE_KERNEL);
+		all_uuids = btrfs_scanned_uuids();
+		list_for_each(cur_uuid, all_uuids) {
+			fs_devices = list_entry(cur_uuid,
+					struct btrfs_fs_devices,
 					list);
-		if (search && uuid_search(fs_devices, search) == 0)
-			continue;
-		print_one_uuid(fs_devices);
+			print_one_uuid(fs_devices);
+		}
+		break;
+	case BTRFS_SCAN_MOUNTED:
+		ret = btrfs_scan_kernel(NULL, 0);
+		if (ret)
+			fprintf(stderr, "ERROR: scan kernel failed, %d\n",
+				ret);
+		break;
 	}
 	printf("%s\n", BTRFS_BUILD_VERSION);
 	return 0;
diff --git a/utils.c b/utils.c
index 86ee948..de182e0 100644
--- a/utils.c
+++ b/utils.c
@@ -680,9 +680,9 @@ int is_block_device(const char *path) {
  * Find the mount point for a mounted device.
  * On success, returns 0 with mountpoint in *mp.
  * On failure, returns -errno (not mounted yields -EINVAL)
- * Is noisy on failures, expects to be given a mounted device.
  */
-static int get_btrfs_mount(const char *dev, char *mp, size_t mp_size) {
+int get_btrfs_mount(const char *dev, char *mp, size_t mp_size)
+{
 	int ret;
 	int fd = -1;
 
@@ -707,7 +707,6 @@ static int get_btrfs_mount(const char *dev, char *mp, size_t mp_size) {
 
 	ret = check_mounted_where(fd, dev, mp, mp_size, NULL);
 	if (!ret) {
-		fprintf(stderr, "%s is not a mounted btrfs device\n", dev);
 		ret = -EINVAL;
 	} else { /* mounted, all good */
 		ret = 0;
@@ -1133,6 +1132,56 @@ fail:
 	return ret;
 }
 
+int test_skip_this_disk(char *path)
+{
+	int fd;
+	/* this will eliminate disks which are mounted (btrfs)
+	 * and non-dm disk path when dm is enabled
+	 */
+	fd = open(path, O_RDWR|O_EXCL);
+	if (fd < 0)
+		return 1;
+	close(fd);
+	return 0;
+}
+
+void scan_for_btrfs_v2(int update_kernel)
+{
+	int fd = -1;
+	u64 num_devices;
+	struct btrfs_fs_devices *tmp_devices;
+	blkid_dev_iterate iter = NULL;
+	blkid_dev dev = NULL;
+	blkid_cache cache = NULL;
+	char path[PATH_MAX];
+
+	if (blkid_get_cache(&cache, 0) < 0) {
+		printf("ERROR: lblkid cache get failed\n");
+		return;
+	}
+	blkid_probe_all(cache);
+	iter = blkid_dev_iterate_begin(cache);
+	blkid_dev_set_search(iter, "TYPE", "btrfs");
+	while (blkid_dev_next(iter, &dev) == 0) {
+		dev = blkid_verify(cache, dev);
+		if (!dev)
+			continue;
+		/* if we are here its definitly a btrfs disk*/
+		strcpy(path, blkid_dev_devname(dev));
+		if (test_skip_this_disk(path))
+			continue;
+
+		fd = open(path, O_RDONLY);
+		btrfs_scan_one_device(fd, path, &tmp_devices,
+				&num_devices, BTRFS_SUPER_INFO_OFFSET);
+		close(fd);
+		fd = -1;
+		if (update_kernel)
+			btrfs_register_one_device(path);
+	}
+	blkid_dev_iterate_end(iter);
+}
+
 int btrfs_scan_for_fsid(int run_ioctls)
 {
 	int ret;
diff --git a/utils.h b/utils.h
index ec06a82..4b449b8 100644
--- a/utils.h
+++ b/utils.h
@@ -25,8 +25,11 @@
 
 #define BTRFS_MKFS_SYSTEM_GROUP_SIZE (4 * 1024 * 1024)
 
-#define BTRFS_SCAN_PROC	1
+#define BTRFS_SCAN_PROC		1
 #define BTRFS_SCAN_DEV		2
+#define BTRFS_SCAN_MOUNTED	3
+
+#define BTRFS_UPDATE_KERNEL	1
 
 int make_btrfs(int fd, const char *device, const char *label,
 	       u64 blocks[6], u64 num_bytes, u32 nodesize,
@@ -74,7 +77,9 @@ u64 btrfs_device_size(int fd, struct stat *st);
 #define strncpy_null(dest, src) __strncpy__null(dest, src, sizeof(dest))
 int test_dev_for_mkfs(char *file, int force_overwrite, char *estr);
 int scan_for_btrfs(int where, int update_kernel);
+void scan_for_btrfs_v2(int update_kernel);
 int get_label_mounted(const char *mount_path, char *labelp);
 int test_num_disk_vs_raid(u64 metadata_profile, u64 data_profile,
 	u64 dev_cnt, int mixed, char *estr);
+int get_btrfs_mount(const char *dev, char *mp, size_t mp_size);
 #endif
-- 
1.7.1

[PATCH 0/2 v3] fi show, dev scan and lblkid

[Anand Jain]

  This patch set is about
  use of lblkid for the btrfs disk scan and
  using this lblkid scan for the fi show and dev scan cli

  This includes the comments from David (to use lblkid)
  and Zach to show (btrfs fi show) info from kernel when
  disk is mounted and from the disks directly when disk
  is unmounted by default

v3:
  rebase on to 20130909
  accepts Davids review comments

v2:
  In an effort fix checkpath.pl errors as suggested in
  Wang's review, the two patches as below is merged
  into one

  btrfs-progs: read from the kernel when disk is mounted
  btrfs-progs: use lblkid to scan and filesystem show improvements


Anand Jain (2):
  btrfs-progs: move out print in cmd_df to another function
  btrfs-progs: use kernel for mounted and lblkid to scan disks

 cmds-device.c     |  19 ++-
 cmds-filesystem.c | 354 ++++++++++++++++++++++++++++++++++++++----------------
 ctree.h           |  11 ++
 man/btrfs.8.in    |  17 +--
 utils.c           |  55 ++++++++-
 utils.h           |   5 +
 6 files changed, 338 insertions(+), 123 deletions(-)

-- 
1.8.4.rc4.1.g0d8beaa

[PATCH 1/2] btrfs-progs: move out print in cmd_df to another function

[Anand Jain]

This is a prepatory work for the btrfs fi show command
fixes. So that we have a function get_df to get the fs sizes

v5:
 rebase on 20130909
 accepts Davids review comments
v4:
 fixes checkpatch.pl errors as suggested by Wang
v3:
 accepts Zach review comments
v2:
combined the other patches as below and rebase
 btrfs-progs: get string for the group profile and type

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
 cmds-filesystem.c | 183 +++++++++++++++++++++++++++++-------------------------
 ctree.h           |  11 ++++
 2 files changed, 108 insertions(+), 86 deletions(-)

diff --git a/cmds-filesystem.c b/cmds-filesystem.c
index 815d59a..e1db9e7 100644
--- a/cmds-filesystem.c
+++ b/cmds-filesystem.c
@@ -44,32 +44,53 @@ static const char * const cmd_df_usage[] = {
 	NULL
 };
 
-static int cmd_df(int argc, char **argv)
+static char *group_type_str(u64 flag)
 {
-	struct btrfs_ioctl_space_args *sargs, *sargs_orig;
-	u64 count = 0, i;
-	int ret;
-	int fd;
-	int e;
-	char *path;
-	DIR  *dirstream = NULL;
-
-	if (check_argc_exact(argc, 2))
-		usage(cmd_df_usage);
-
-	path = argv[1];
-
-	fd = open_file_or_dir(path, &dirstream);
-	if (fd < 0) {
-		fprintf(stderr, "ERROR: can't access to '%s'\n", path);
-		return 1;
+	switch (flag & BTRFS_BLOCK_GROUP_TYPE_MASK) {
+	case BTRFS_BLOCK_GROUP_DATA:
+		return "Data";
+	case BTRFS_BLOCK_GROUP_SYSTEM:
+		return "System";
+	case BTRFS_BLOCK_GROUP_METADATA:
+		return "Metadata";
+	case BTRFS_BLOCK_GROUP_DATA|BTRFS_BLOCK_GROUP_METADATA:
+		return "Data+Metadata";
+	default:
+		return "unknown";
 	}
+}
 
-	sargs_orig = sargs = malloc(sizeof(struct btrfs_ioctl_space_args));
-	if (!sargs) {
-		ret = -ENOMEM;
-		goto out;
+static char *group_profile_str(u64 flag)
+{
+	switch (flag & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
+	case 0:
+		return "single";
+	case BTRFS_BLOCK_GROUP_RAID0:
+		return "RAID0";
+	case BTRFS_BLOCK_GROUP_RAID1:
+		return "RAID1";
+	case BTRFS_BLOCK_GROUP_RAID5:
+		return "RAID5";
+	case BTRFS_BLOCK_GROUP_RAID6:
+		return "RAID6";
+	case BTRFS_BLOCK_GROUP_DUP:
+		return "DUP";
+	case BTRFS_BLOCK_GROUP_RAID10:
+		return "RAID10";
+	default:
+		return "unknown";
 	}
+}
+
+static int get_df(int fd, struct btrfs_ioctl_space_args **sargs_ret)
+{
+	u64 count = 0;
+	int ret, e;
+	struct btrfs_ioctl_space_args *sargs;
+
+	sargs = malloc(sizeof(struct btrfs_ioctl_space_args));
+	if (!sargs)
+		return -ENOMEM;
 
 	sargs->space_slots = 0;
 	sargs->total_spaces = 0;
@@ -77,89 +98,79 @@ static int cmd_df(int argc, char **argv)
 	ret = ioctl(fd, BTRFS_IOC_SPACE_INFO, sargs);
 	e = errno;
 	if (ret) {
-		fprintf(stderr, "ERROR: couldn't get space info on '%s' - %s\n",
-			path, strerror(e));
-		goto out;
+		fprintf(stderr, "ERROR: couldn't get space info - %s\n",
+			strerror(e));
+		free(sargs);
+		return ret;
 	}
 	if (!sargs->total_spaces) {
-		ret = 0;
-		goto out;
+		free(sargs);
+		return 0;
 	}
-
 	count = sargs->total_spaces;
+	free(sargs);
 
-	sargs = realloc(sargs, sizeof(struct btrfs_ioctl_space_args) +
+	sargs = malloc(sizeof(struct btrfs_ioctl_space_args) +
 			(count * sizeof(struct btrfs_ioctl_space_info)));
-	if (!sargs) {
-		sargs = sargs_orig;
+	if (!sargs)
 		ret = -ENOMEM;
-		goto out;
-	}
 
 	sargs->space_slots = count;
 	sargs->total_spaces = 0;
-
 	ret = ioctl(fd, BTRFS_IOC_SPACE_INFO, sargs);
 	e = errno;
 	if (ret) {
-		fprintf(stderr, "ERROR: couldn't get space info on '%s' - %s\n",
-			path, strerror(e));
-		goto out;
+		fprintf(stderr, "ERROR: get space info count %llu - %s\n",
+				count, strerror(e));
+		free(sargs);
+		return ret;
 	}
+	*sargs_ret = sargs;
+	return 0;
+}
 
-	for (i = 0; i < sargs->total_spaces; i++) {
-		char description[80];
-		int written = 0;
-		u64 flags = sargs->spaces[i].flags;
-
-		memset(description, 0, 80);
-
-		if (flags & BTRFS_BLOCK_GROUP_DATA) {
-			if (flags & BTRFS_BLOCK_GROUP_METADATA) {
-				snprintf(description, 14, "%s",
-					 "Data+Metadata");
-				written += 13;
-			} else {
-				snprintf(description, 5, "%s", "Data");
-				written += 4;
-			}
-		} else if (flags & BTRFS_BLOCK_GROUP_SYSTEM) {
-			snprintf(description, 7, "%s", "System");
-			written += 6;
-		} else if (flags & BTRFS_BLOCK_GROUP_METADATA) {
-			snprintf(description, 9, "%s", "Metadata");
-			written += 8;
-		}
+static void print_df(struct btrfs_ioctl_space_args *sargs)
+{
+	u64 i;
+	struct btrfs_ioctl_space_info *sp = sargs->spaces;
+
+	for (i = 0; i < sargs->total_spaces; i++, sp++) {
+		printf("%s, %s: total=%s, used=%s\n",
+			group_type_str(sp->flags),
+			group_profile_str(sp->flags),
+			pretty_size(sp->total_bytes),
+			pretty_size(sp->used_bytes));
+	}
+}
 
-		if (flags & BTRFS_BLOCK_GROUP_RAID0) {
-			snprintf(description+written, 8, "%s", ", RAID0");
-			written += 7;
-		} else if (flags & BTRFS_BLOCK_GROUP_RAID1) {
-			snprintf(description+written, 8, "%s", ", RAID1");
-			written += 7;
-		} else if (flags & BTRFS_BLOCK_GROUP_DUP) {
-			snprintf(description+written, 6, "%s", ", DUP");
-			written += 5;
-		} else if (flags & BTRFS_BLOCK_GROUP_RAID10) {
-			snprintf(description+written, 9, "%s", ", RAID10");
-			written += 8;
-		} else if (flags & BTRFS_BLOCK_GROUP_RAID5) {
-			snprintf(description+written, 9, "%s", ", RAID5");
-			written += 7;
-		} else if (flags & BTRFS_BLOCK_GROUP_RAID6) {
-			snprintf(description+written, 9, "%s", ", RAID6");
-			written += 7;
-		}
+static int cmd_df(int argc, char **argv)
+{
+	struct btrfs_ioctl_space_args *sargs = NULL;
+	int ret;
+	int fd;
+	char *path;
+	DIR  *dirstream = NULL;
 
-		printf("%s: total=%s, used=%s\n", description,
-			pretty_size(sargs->spaces[i].total_bytes),
-			pretty_size(sargs->spaces[i].used_bytes));
+	if (check_argc_exact(argc, 2))
+		usage(cmd_df_usage);
+
+	path = argv[1];
+
+	fd = open_file_or_dir(path, &dirstream);
+	if (fd < 0) {
+		fprintf(stderr, "ERROR: can't access to '%s'\n", path);
+		return 1;
 	}
-out:
-	close_file_or_dir(fd, dirstream);
-	free(sargs);
+	ret = get_df(fd, &sargs);
+
+	if (!ret && sargs) {
+		print_df(sargs);
+		free(sargs);
+	} else
+		fprintf(stderr, "ERROR: get_df failed %s\n", strerror(ret));
 
-	return !!ret;
+	close_file_or_dir(fd, dirstream);
+	return ret;
 }
 
 static int uuid_search(struct btrfs_fs_devices *fs_devices, char *search)
diff --git a/ctree.h b/ctree.h
index 3d6596c..e928a8e 100644
--- a/ctree.h
+++ b/ctree.h
@@ -836,6 +836,17 @@ struct btrfs_csum_item {
 #define BTRFS_BLOCK_GROUP_RAID6    (1ULL << 8)
 #define BTRFS_BLOCK_GROUP_RESERVED	BTRFS_AVAIL_ALLOC_BIT_SINGLE
 
+#define BTRFS_BLOCK_GROUP_TYPE_MASK	(BTRFS_BLOCK_GROUP_DATA |    \
+					 BTRFS_BLOCK_GROUP_SYSTEM |  \
+					 BTRFS_BLOCK_GROUP_METADATA)
+
+#define BTRFS_BLOCK_GROUP_PROFILE_MASK	(BTRFS_BLOCK_GROUP_RAID0 |   \
+					 BTRFS_BLOCK_GROUP_RAID1 |   \
+					 BTRFS_BLOCK_GROUP_RAID5 |   \
+					 BTRFS_BLOCK_GROUP_RAID6 |   \
+					 BTRFS_BLOCK_GROUP_DUP |     \
+					 BTRFS_BLOCK_GROUP_RAID10)
+
 /* used in struct btrfs_balance_args fields */
 #define BTRFS_AVAIL_ALLOC_BIT_SINGLE	(1ULL << 48)
 
-- 
1.8.4.rc4.1.g0d8beaa

[PATCH 2/2] btrfs-progs: use kernel for mounted and lblkid to scan disks

[Anand Jain]

As of now btrfs filesystem show reads directly from
disks. So sometimes output can be stale, mainly when
user wants to cross verify their operation like,
label or device delete or add... etc. so this
patch will read from the kernel ioctl if it finds
that disk is mounted.

Further, to scan for the disks this patch will use
lblkid which would replace the our own scan of
/proc/partitions

Further, this patch adds new parameters mounted and
group profile info in the filesystem show output
---------------
btrfs fi show
Label: none  uuid: a2446ecf-68c5-4815-8b63-099d10fc373c mounted: /btrfs
	Group profile: metadata: single  metadata: DUP  data: single
	Total devices 1 FS bytes used 32.00KiB
	devid    1 size 1.98GiB used 238.25MiB path /dev/mapper/mpatha

Label: none  uuid: aea4f4a7-39f2-43dc-bee1-03533551c1a0 (unmounted)
	Total devices 1 FS bytes used 28.00KiB
	devid    1 size 2.00GiB used 240.75MiB path /dev/mapper/mpathb
------------

v2:
  accepts David suggested

Signed-off-by: Anand Jain <anand.jain@oracle.com>
---
 cmds-device.c     |  19 ++++--
 cmds-filesystem.c | 171 +++++++++++++++++++++++++++++++++++++++++++++++-------
 man/btrfs.8.in    |  17 +++---
 utils.c           |  55 +++++++++++++++++-
 utils.h           |   5 ++
 5 files changed, 230 insertions(+), 37 deletions(-)

diff --git a/cmds-device.c b/cmds-device.c
index 800a050..94ba2f2 100644
--- a/cmds-device.c
+++ b/cmds-device.c
@@ -179,7 +179,7 @@ static const char * const cmd_scan_dev_usage[] = {
 static int cmd_scan_dev(int argc, char **argv)
 {
 	int	i, fd, e;
-	int	where = BTRFS_SCAN_PROC;
+	int	where = 0;
 	int	devstart = 1;
 
 	if( argc > 1 && !strcmp(argv[1],"--all-devices")){
@@ -193,14 +193,21 @@ static int cmd_scan_dev(int argc, char **argv)
 	if(argc<=devstart){
 		int ret;
 		printf("Scanning for Btrfs filesystems\n");
-		ret = scan_for_btrfs(where, 1);
-		if (ret){
-			fprintf(stderr, "ERROR: error %d while scanning\n", ret);
-			return 1;
-		}
+		if (where == BTRFS_SCAN_DEV) {
+			ret = scan_for_btrfs(BTRFS_SCAN_DEV,
+						BTRFS_UPDATE_KERNEL);
+			if (ret) {
+				fprintf(stderr,
+					"ERROR: %d while scanning\n", ret);
+				return 1;
+			}
+		} else
+			scan_for_btrfs_v2(BTRFS_UPDATE_KERNEL);
+
 		return 0;
 	}
 
+	/* if its here that means scan the specificed device/file */
 	fd = open("/dev/btrfs-control", O_RDWR);
 	if (fd < 0) {
 		perror("failed to open /dev/btrfs-control");
diff --git a/cmds-filesystem.c b/cmds-filesystem.c
index e1db9e7..80b6de1 100644
--- a/cmds-filesystem.c
+++ b/cmds-filesystem.c
@@ -22,6 +22,9 @@
 #include <errno.h>
 #include <uuid/uuid.h>
 #include <ctype.h>
+#include <mntent.h>
+#include <fcntl.h>
+#include <linux/limits.h>
 
 #include "kerncompat.h"
 #include "ctree.h"
@@ -212,8 +215,9 @@ static void print_one_uuid(struct btrfs_fs_devices *fs_devices)
 
 
 	total = device->total_devs;
-	printf(" uuid: %s\n\tTotal devices %llu FS bytes used %s\n", uuidbuf,
-	       (unsigned long long)total,
+
+	printf(" uuid: %s (unmounted)\n\tTotal devices %llu FS bytes used %s\n",
+		uuidbuf, (unsigned long long)total,
 	       pretty_size(device->super_bytes_used));
 
 	list_for_each(cur, &fs_devices->devices) {
@@ -232,10 +236,98 @@ static void print_one_uuid(struct btrfs_fs_devices *fs_devices)
 	printf("\n");
 }
 
+/* adds up all the used spaces as reported by the space info ioctl
+ */
+static u64 calc_used_bytes(struct btrfs_ioctl_space_args *si)
+{
+	u64 ret = 0;
+	int i;
+	for (i = 0; i < si->total_spaces; i++)
+		ret += si->spaces[i].used_bytes;
+	return ret;
+}
+
+static int print_one_fs(struct btrfs_ioctl_fs_info_args *fi,
+		struct btrfs_ioctl_dev_info_args *di_n,
+		struct btrfs_ioctl_space_args *si_n, char *label, char *path)
+{
+	int i;
+	char uuidbuf[37];
+	struct btrfs_ioctl_dev_info_args *di = di_n;
+	u64 flags;
+
+	uuid_unparse(fi->fsid, uuidbuf);
+	printf("Label: %s  uuid: %s mounted: %s\n",
+		strlen(label) ? label : "none", uuidbuf, path);
+	printf("\tGroup profile:");
+	for (i = si_n->total_spaces - 1; i >= 0; i--) {
+		flags = si_n->spaces[i].flags;
+		if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
+			continue;
+		printf(" %s: %s", group_type_str(flags),
+					group_profile_str(flags));
+		printf(" ");
+	}
+	printf("\n");
+
+	printf("\tTotal devices %llu FS bytes used %s\n",
+				fi->num_devices,
+			pretty_size(calc_used_bytes(si_n)));
+
+	for (i = 0; i < fi->num_devices; i++) {
+		di = (struct btrfs_ioctl_dev_info_args *)&di_n[i];
+		printf("\tdevid    %llu size %s used %s path %s\n",
+			di->devid,
+			pretty_size(di->total_bytes),
+			pretty_size(di->bytes_used),
+			di->path);
+	}
+
+	printf("\n");
+	return 0;
+}
+
+static int btrfs_scan_kernel()
+{
+	int ret = 0, fd;
+	FILE *f;
+	struct mntent *mnt;
+	struct btrfs_ioctl_fs_info_args fs_info_arg;
+	struct btrfs_ioctl_dev_info_args *dev_info_arg = NULL;
+	struct btrfs_ioctl_space_args *space_info_arg;
+	char label[BTRFS_LABEL_SIZE];
+
+	f = setmntent("/proc/self/mounts", "r");
+	if (f == NULL)
+		return 1;
+
+	while ((mnt = getmntent(f)) != NULL) {
+		if (strcmp(mnt->mnt_type, "btrfs"))
+			continue;
+		ret = get_fs_info(mnt->mnt_dir, &fs_info_arg,
+				&dev_info_arg);
+		if (ret)
+			return ret;
+
+		fd = open(mnt->mnt_dir, O_RDONLY);
+		if (fd > 0 && !get_df(fd, &space_info_arg)) {
+			get_label_mounted(mnt->mnt_dir, label);
+			print_one_fs(&fs_info_arg, dev_info_arg,
+				space_info_arg, label, mnt->mnt_dir);
+			free(space_info_arg);
+		}
+		if (fd > 0)
+			close(fd);
+		free(dev_info_arg);
+	}
+	return ret;
+}
+
 static const char * const cmd_show_usage[] = {
-	"btrfs filesystem show [--all-devices|<uuid>]",
-	"Show the structure of a filesystem",
+	"btrfs filesystem show [--mounted|--all-devices [<uuid>]]",
+	"Show the structure of btrfs filesystem(s)",
 	"If no argument is given, structure of all present filesystems is shown.",
+	"--mounted  show only the mounted btrfs filesystem",
 	NULL
 };
 
@@ -246,34 +338,73 @@ static int cmd_show(int argc, char **argv)
 	struct list_head *cur_uuid;
 	char *search = NULL;
 	int ret;
-	int where = BTRFS_SCAN_PROC;
+	int where = 0;
 	int searchstart = 1;
 
 	if( argc > 1 && !strcmp(argv[1],"--all-devices")){
 		where = BTRFS_SCAN_DEV;
 		searchstart += 1;
+	} else if (argc > 1 && !strcmp(argv[1], "--mounted")) {
+		where = BTRFS_SCAN_MOUNTED;
+		searchstart += 1;
 	}
 
-	if (check_argc_max(argc, searchstart + 1))
-		usage(cmd_show_usage);
-
-	ret = scan_for_btrfs(where, 0);
-
-	if (ret){
-		fprintf(stderr, "ERROR: error %d while scanning\n", ret);
-		return 1;
+	if (where == BTRFS_SCAN_DEV) {
+		if (check_argc_max(argc, searchstart + 1))
+			usage(cmd_show_usage);
+	} else if (where == BTRFS_SCAN_MOUNTED) {
+		if (check_argc_max(argc, searchstart))
+			usage(cmd_show_usage);
+	} else {
+		if (check_argc_max(argc, searchstart))
+			usage(cmd_show_usage);
 	}
-	
+
 	if(searchstart < argc)
 		search = argv[searchstart];
 
-	all_uuids = btrfs_scanned_uuids();
-	list_for_each(cur_uuid, all_uuids) {
-		fs_devices = list_entry(cur_uuid, struct btrfs_fs_devices,
+	switch (where) {
+	case 0:
+		/* no option : show both mounted and unmounted
+		 */
+		/* mounted */
+		ret = btrfs_scan_kernel();
+		if (ret)
+			fprintf(stderr, "ERROR: scan kernel failed, %d\n",
+				ret);
+
+		/* unmounted */
+		scan_for_btrfs_v2(!BTRFS_UPDATE_KERNEL);
+		all_uuids = btrfs_scanned_uuids();
+		list_for_each(cur_uuid, all_uuids) {
+			fs_devices = list_entry(cur_uuid,
+					struct btrfs_fs_devices,
 					list);
-		if (search && uuid_search(fs_devices, search) == 0)
-			continue;
-		print_one_uuid(fs_devices);
+			print_one_uuid(fs_devices);
+		}
+		break;
+	case BTRFS_SCAN_DEV:
+		ret = scan_for_btrfs(BTRFS_SCAN_DEV, !BTRFS_UPDATE_KERNEL);
+		if (ret) {
+			fprintf(stderr, "ERROR: %d while scanning\n", ret);
+			return 1;
+		}
+		all_uuids = btrfs_scanned_uuids();
+		list_for_each(cur_uuid, all_uuids) {
+			fs_devices = list_entry(cur_uuid,
+					struct btrfs_fs_devices,
+					list);
+			if (search && uuid_search(fs_devices, search) == 0)
+				continue;
+			print_one_uuid(fs_devices);
+		}
+		break;
+	case BTRFS_SCAN_MOUNTED:
+		ret = btrfs_scan_kernel();
+		if (ret)
+			fprintf(stderr, "ERROR: scan kernel failed, %d\n",
+				ret);
+		break;
 	}
 	printf("%s\n", BTRFS_BUILD_VERSION);
 	return 0;
diff --git a/man/btrfs.8.in b/man/btrfs.8.in
index 61ffe8d..6a4f5bc 100644
--- a/man/btrfs.8.in
+++ b/man/btrfs.8.in
@@ -25,7 +25,7 @@ btrfs \- control a btrfs filesystem
 .PP
 \fBbtrfs\fP \fBfilesystem df\fP\fI <path>\fP
 .PP
-\fBbtrfs\fP \fBfilesystem show\fP [--all-devices|\fI<uuid>\fP|\fI<label>\fP]\fP
+\fBbtrfs\fP \fBfilesystem show\fP [\fI--mounted\fP|\fI--all-devices\fP|\fI<uuid>\fP]\fP
 .PP
 \fBbtrfs\fP \fBfilesystem sync\fP\fI <path> \fP
 .PP
@@ -51,7 +51,7 @@ btrfs \- control a btrfs filesystem
 .PP
 \fBbtrfs\fP \fBdevice delete\fP \fI<device>\fP [\fI<device>...\fP] \fI<path>\fP
 .PP
-\fBbtrfs\fP \fBdevice scan\fP [--all-devices|\fI<device> \fP[\fI<device>...\fP]
+\fBbtrfs\fP \fBdevice scan\fP [\fI--all-devices\fP|\fI<device> \P[\fI<device>...\fP]
 .PP
 \fBbtrfs\fP \fBdevice ready\fP\fI <device>\fP
 .PP
@@ -259,11 +259,12 @@ Show information of a given subvolume in the \fI<path>\fR.
 Show space usage information for a mount point.
 .TP
 
-\fBfilesystem show\fR [--all-devices|\fI<uuid>\fR|\fI<label>\fR]\fR
-Show the btrfs filesystem with some additional info. If no \fIUUID\fP or
-\fIlabel\fP is passed, \fBbtrfs\fR show info of all the btrfs filesystem.
+\fBfilesystem show\fR [\fI--mounted\fP|\fI--all-devices\fP|\fI<uuid>\fR]\fR
+Show the btrfs filesystem with some additional info. If no option or \fIUUID\fP
+is passed, \fBbtrfs\fR shows information of all the btrfs filesystem both mounted
+and unmounted.
+If \fB--mounted\fP is passed, it would probe btrfs kernel to list mounted btrfs filesystem(s);
 If \fB--all-devices\fP is passed, all the devices under /dev are scanned;
-otherwise the devices list is extracted from the /proc/partitions file.
 .TP
 
 \fBfilesystem sync\fR\fI <path> \fR
@@ -396,8 +397,8 @@ Remove device(s) from a filesystem identified by \fI<path>\fR.
 
 \fBdevice scan\fR [--all-devices|\fI<device> \fP[\fI<device>...\fP]\fR
 If one or more devices are passed, these are scanned for a btrfs filesystem. 
-If no devices are passed, \fBbtrfs\fR scans all the block devices listed
-in the /proc/partitions file.
+If no devices are passed, \fBbtrfs\fR uses block devices containing btrfs
+filesystem as listed by blkid.
 Finally, if \fB--all-devices\fP is passed, all the devices under /dev are 
 scanned.
 .TP
diff --git a/utils.c b/utils.c
index 134bf80..02a2658 100644
--- a/utils.c
+++ b/utils.c
@@ -685,9 +685,9 @@ int is_block_device(const char *path) {
  * Find the mount point for a mounted device.
  * On success, returns 0 with mountpoint in *mp.
  * On failure, returns -errno (not mounted yields -EINVAL)
- * Is noisy on failures, expects to be given a mounted device.
  */
-static int get_btrfs_mount(const char *dev, char *mp, size_t mp_size) {
+int get_btrfs_mount(const char *dev, char *mp, size_t mp_size)
+{
 	int ret;
 	int fd = -1;
 
@@ -712,7 +712,6 @@ static int get_btrfs_mount(const char *dev, char *mp, size_t mp_size) {
 
 	ret = check_mounted_where(fd, dev, mp, mp_size, NULL);
 	if (!ret) {
-		fprintf(stderr, "%s is not a mounted btrfs device\n", dev);
 		ret = -EINVAL;
 	} else { /* mounted, all good */
 		ret = 0;
@@ -1144,6 +1143,56 @@ fail:
 	return ret;
 }
 
+int test_skip_this_disk(char *path)
+{
+	int fd;
+	/* this will eliminate disks which are mounted (btrfs)
+	 * and non-dm disk path when dm is enabled
+	 */
+	fd = open(path, O_RDWR|O_EXCL);
+	if (fd < 0)
+		return 1;
+	close(fd);
+	return 0;
+}
+
+void scan_for_btrfs_v2(int update_kernel)
+{
+	int fd = -1;
+	u64 num_devices;
+	struct btrfs_fs_devices *tmp_devices;
+	blkid_dev_iterate iter = NULL;
+	blkid_dev dev = NULL;
+	blkid_cache cache = NULL;
+	char path[PATH_MAX];
+
+	if (blkid_get_cache(&cache, 0) < 0) {
+		printf("ERROR: lblkid cache get failed\n");
+		return;
+	}
+	blkid_probe_all(cache);
+	iter = blkid_dev_iterate_begin(cache);
+	blkid_dev_set_search(iter, "TYPE", "btrfs");
+	while (blkid_dev_next(iter, &dev) == 0) {
+		dev = blkid_verify(cache, dev);
+		if (!dev)
+			continue;
+		/* if we are here its definitly a btrfs disk*/
+		strcpy(path, blkid_dev_devname(dev));
+		if (test_skip_this_disk(path))
+			continue;
+
+		fd = open(path, O_RDONLY);
+		btrfs_scan_one_device(fd, path, &tmp_devices,
+				&num_devices, BTRFS_SUPER_INFO_OFFSET);
+		close(fd);
+		fd = -1;
+		if (update_kernel)
+			btrfs_register_one_device(path);
+	}
+	blkid_dev_iterate_end(iter);
+}
+
 int btrfs_scan_for_fsid(int run_ioctls)
 {
 	int ret;
diff --git a/utils.h b/utils.h
index 6c2553a..616bae1 100644
--- a/utils.h
+++ b/utils.h
@@ -27,6 +27,9 @@
 
 #define BTRFS_SCAN_PROC	1
 #define BTRFS_SCAN_DEV		2
+#define BTRFS_SCAN_MOUNTED	3
+
+#define BTRFS_UPDATE_KERNEL	1
 
 int make_btrfs(int fd, const char *device, const char *label,
 	       u64 blocks[6], u64 num_bytes, u32 nodesize,
@@ -74,10 +77,12 @@ u64 btrfs_device_size(int fd, struct stat *st);
 #define strncpy_null(dest, src) __strncpy__null(dest, src, sizeof(dest))
 int test_dev_for_mkfs(char *file, int force_overwrite, char *estr);
 int scan_for_btrfs(int where, int update_kernel);
+void scan_for_btrfs_v2(int update_kernel);
 int get_label_mounted(const char *mount_path, char *labelp);
 int test_num_disk_vs_raid(u64 metadata_profile, u64 data_profile,
 	u64 dev_cnt, int mixed, char *estr);
 int is_vol_small(char *file);
 int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
 			   int verify);
+int get_btrfs_mount(const char *dev, char *mp, size_t mp_size);
 #endif
-- 
1.8.4.rc4.1.g0d8beaa

Re: [PATCH 1/2] btrfs-progs: move out print in cmd_df to another function

[David Sterba]

On Fri, Sep 13, 2013 at 07:32:22PM +0800, Anand Jain wrote:
> +static int get_df(int fd, struct btrfs_ioctl_space_args **sargs_ret)
> +{

This function returns full error codes, that's ok,

> @@ -77,89 +98,79 @@ static int cmd_df(int argc, char **argv)
>  	ret = ioctl(fd, BTRFS_IOC_SPACE_INFO, sargs);
>  	e = errno;
>  	if (ret) {
> -		fprintf(stderr, "ERROR: couldn't get space info on '%s' - %s\n",
> -			path, strerror(e));
> -		goto out;
> +		fprintf(stderr, "ERROR: couldn't get space info - %s\n",
> +			strerror(e));
> +		free(sargs);
> +		return ret;

cmd_df should return the 0-1 normalized value after the cleanup that
Wang Shilong has done. You can leave the common exit block (ie. goto +
free/return as before) and use return !!ret.

Re: [PATCH 2/2] btrfs-progs: use kernel for mounted and lblkid to scan disks

[David Sterba]

On Fri, Sep 13, 2013 at 07:32:23PM +0800, Anand Jain wrote:
> Further, this patch adds new parameters mounted and
> group profile info in the filesystem show output

Sorry to bother you, but the 'further' part of the patch should be
separated out. The core change of the patch is to use libblkid and the
ioctl.

> ---------------
> btrfs fi show
> Label: none  uuid: a2446ecf-68c5-4815-8b63-099d10fc373c mounted: /btrfs
> 	Group profile: metadata: single  metadata: DUP  data: single

I didn't notice that before, this does not bring much information
without the numbers as 'fi df' does. Please drop the printf lines

> @@ -246,34 +338,73 @@ static int cmd_show(int argc, char **argv)
>  	struct list_head *cur_uuid;
>  	char *search = NULL;
>  	int ret;
> -	int where = BTRFS_SCAN_PROC;
> +	int where = 0;
>  	int searchstart = 1;
>  
>  	if( argc > 1 && !strcmp(argv[1],"--all-devices")){
>  		where = BTRFS_SCAN_DEV;
>  		searchstart += 1;
> +	} else if (argc > 1 && !strcmp(argv[1], "--mounted")) {
> +		where = BTRFS_SCAN_MOUNTED;
> +		searchstart += 1;

getopt was not used here, but with the new options it probably should
be, because

> -	if (check_argc_max(argc, searchstart + 1))
> -		usage(cmd_show_usage);
> -
> -	ret = scan_for_btrfs(where, 0);
> -
> -	if (ret){
> -		fprintf(stderr, "ERROR: error %d while scanning\n", ret);
> -		return 1;
> +	if (where == BTRFS_SCAN_DEV) {
> +		if (check_argc_max(argc, searchstart + 1))
> +			usage(cmd_show_usage);
> +	} else if (where == BTRFS_SCAN_MOUNTED) {
> +		if (check_argc_max(argc, searchstart))
> +			usage(cmd_show_usage);
> +	} else {
> +		if (check_argc_max(argc, searchstart))
> +			usage(cmd_show_usage);

this stops to work:

$ btrfs fi show SOME-UUID
btrfs filesystem show: too many arguments


thanks,
david

Re: [PATCH 2/2] btrfs-progs: use kernel for mounted and lblkid to scan disks

[Anand Jain]

>> ---------------
>> btrfs fi show
>> Label: none  uuid: a2446ecf-68c5-4815-8b63-099d10fc373c mounted: /btrfs
>> 	Group profile: metadata: single  metadata: DUP  data: single
>
> I didn't notice that before, this does not bring much information
> without the numbers as 'fi df' does. Please drop the printf lines

  Thanks for the review.
  IMO group profile is useful info to have it at both the places.
  end user using this new btrfs fi show would surely notice that it
  will reduce other commands normally used following the current
  btrfs fi show command. (like mount and btrfs fi df). of course
  user should use fi df to know detailed info about the sizes.

-------
btrfs fi show
Label: none  uuid: 2c654c36-ba53-4cc8-9c95-f0bee667b9a6 mounted: /btrfs
	Group profile: Data+Metadata: single
	Total devices 2 FS bytes used 3.17MiB
	devid    1 size 1.98GiB used 12.00MiB path /dev/mapper/mpatha
	devid    2 size 2.00GiB used 416.00MiB path /dev/mapper/mpathb
-------

Thanks, Anand

Re: [PATCH 2/2] btrfs-progs: use kernel for mounted and lblkid to scan disks

[David Sterba]

On Sun, Sep 15, 2013 at 12:30:35PM +0800, Anand Jain wrote:
>  IMO group profile is useful info to have it at both the places.
>  end user using this new btrfs fi show would surely notice that it
>  will reduce other commands normally used following the current
>  btrfs fi show command. (like mount and btrfs fi df). of course
>  user should use fi df to know detailed info about the sizes.

Yeah, the output of df/show needs reworking, but please do not mix
unrelated changes to other patches, although it may be too tempting in
this particular case.

david