Btrfs-progs: tool to visualize fragmentation

This tool draws per-chunk pngs representing the allocation map. A black
or colored dot means the block is allocated.
The output is written to a subdirectory, together with an index.html to be
viewed in a browser.
There are options to control whether color should be used and which block
group types should be printed.
To build, you need to have libpng and libgd installed. It is not part of
the 'all' target, so please build it explicitely with make btrfs-fragments.

A (rather untypical) example can be seen at

http://sensille.com/fragments

Please regard this as a first scratch version and feel free to improve it :)

Signed-off-by: Arne Jansen <sensille@gmx.net>

4 files changed, 465 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
index 29836ed4..a7e1b196 100644
--- a/.gitignore
+++ b/.gitignore
@@ -8,6 +8,7 @@ btrfs
 btrfs.static
 btrfs-debug-tree
 btrfs-map-logical
+btrfs-fragments
 btrfsck
 calc-size
 ioctl-test
diff --git a/Makefile b/Makefile
index 2648d374..a270e9ca 100644
--- a/Makefile
+++ b/Makefile
@@ -186,6 +186,10 @@ btrfs-convert: $(objects) $(libs) convert.o
 	@echo "    [LD]     $@"
 	$(Q)$(CC) $(CFLAGS) -o btrfs-convert $(objects) convert.o -lext2fs -lcom_err $(LDFLAGS) $(LIBS)
 
+btrfs-fragments: $(objects) $(libs) fragments.o
+	@echo "    [LD]     $@"
+	$(Q)$(CC) $(CFLAGS) -o btrfs-fragments $(objects) fragments.o $(LDFLAGS) $(LIBS) -lgd -lpng -ljpeg -lfreetype
+
 ioctl-test: $(objects) $(libs) ioctl-test.o
 	@echo "    [LD]     $@"
 	$(Q)$(CC) $(CFLAGS) -o ioctl-test $(objects) ioctl-test.o $(LDFLAGS) $(LIBS)
diff --git a/ctree.h b/ctree.h
index 9442e037..953cc6ec 100644
--- a/ctree.h
+++ b/ctree.h
@@ -1391,9 +1391,11 @@ static inline u8 *btrfs_dev_extent_chunk_tree_uuid(struct btrfs_dev_extent *dev)
 
 /* struct btrfs_extent_item */
 BTRFS_SETGET_FUNCS(extent_refs, struct btrfs_extent_item, refs, 64);
+BTRFS_SETGET_STACK_FUNCS(stack_extent_refs, struct btrfs_extent_item, refs, 64);
 BTRFS_SETGET_FUNCS(extent_generation, struct btrfs_extent_item,
 		   generation, 64);
 BTRFS_SETGET_FUNCS(extent_flags, struct btrfs_extent_item, flags, 64);
+BTRFS_SETGET_STACK_FUNCS(stack_extent_flags, struct btrfs_extent_item, flags, 64);
 
 BTRFS_SETGET_FUNCS(extent_refs_v0, struct btrfs_extent_item_v0, refs, 32);
 
@@ -1429,6 +1431,10 @@ BTRFS_SETGET_FUNCS(extent_inline_ref_type, struct btrfs_extent_inline_ref,
 		   type, 8);
 BTRFS_SETGET_FUNCS(extent_inline_ref_offset, struct btrfs_extent_inline_ref,
 		   offset, 64);
+BTRFS_SETGET_STACK_FUNCS(stack_extent_inline_ref_type,
+			 struct btrfs_extent_inline_ref, type, 8);
+BTRFS_SETGET_STACK_FUNCS(stack_extent_inline_ref_offset,
+			 struct btrfs_extent_inline_ref, offset, 64);
 
 static inline u32 btrfs_extent_inline_ref_size(int type)
 {
diff --git a/fragments.c b/fragments.c
new file mode 100644
index 00000000..a012fe1b
--- /dev/null
+++ b/fragments.c
@@ -0,0 +1,454 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <libgen.h>
+#include <limits.h>
+#include <uuid/uuid.h>
+#include <ctype.h>
+
+#include <gd.h>
+
+#undef ULONG_MAX
+
+#include "kerncompat.h"
+#include "ctree.h"
+#include "ioctl.h"
+#include "utils.h"
+
+static int use_color;
+static void
+push_im(gdImagePtr im, char *name, char *dir)
+{
+	char fullname[2000];
+	FILE *pngout;
+
+	if (!im)
+		return;
+
+	snprintf(fullname, sizeof(fullname), "%s/%s", dir, name);
+	pngout = fopen(fullname, "w");
+	if (!pngout) {
+		printf("unable to create file %s\n", fullname);
+		exit(1);
+	}
+
+	gdImagePng(im, pngout);
+
+	fclose(pngout);
+	gdImageDestroy(im);
+}
+
+static char *
+chunk_type(u64 flags)
+{
+	switch (flags & (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_DATA |
+			 BTRFS_BLOCK_GROUP_METADATA)) {
+	case BTRFS_BLOCK_GROUP_SYSTEM:
+		return "system";
+	case BTRFS_BLOCK_GROUP_DATA:
+		return "data";
+	case BTRFS_BLOCK_GROUP_METADATA:
+		return "metadata";
+	case BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA:
+		return "mixed";
+	default:
+		return "invalid";
+	}
+}
+
+static void
+print_bg(FILE *html, char *name, u64 start, u64 len, u64 used, u64 flags,
+	 u64 areas)
+{
+	double frag = (double)areas / (len / 4096) * 2;
+
+	fprintf(html, "<p>%s chunk starts at %lld, size is %s, %.2f%% used, "
+		      "%.2f%% fragmented</p>\n", chunk_type(flags), start,
+		      pretty_sizes(len), 100.0 * used / len, 100.0 * frag);
+	fprintf(html, "<img src=\"%s\" border=\"1\" />\n", name);
+}
+
+enum tree_colors {
+	COLOR_ROOT = 0,
+	COLOR_EXTENT,
+	COLOR_CHUNK,
+	COLOR_DEV,
+	COLOR_FS,
+	COLOR_CSUM,
+	COLOR_RELOC,
+	COLOR_DATA,
+	COLOR_UNKNOWN,
+	COLOR_MAX
+};
+
+static int
+get_color(struct btrfs_extent_item *item, int len)
+{
+	u64 refs;
+	u64 flags;
+	u8 type;
+	u64 offset;
+	struct btrfs_extent_inline_ref *ref;
+
+	refs = btrfs_stack_extent_refs(item);
+	flags = btrfs_stack_extent_flags(item);
+
+	if (flags & BTRFS_EXTENT_FLAG_DATA)
+		return COLOR_DATA;
+	if (refs > 1) {
+		/* this must be an fs tree */
+		return COLOR_FS;
+	}
+
+	ref = (void *)item + sizeof(struct btrfs_extent_item) +
+			     sizeof(struct btrfs_tree_block_info);
+	type = btrfs_stack_extent_inline_ref_type(ref);
+	offset = btrfs_stack_extent_inline_ref_offset(ref);
+
+	switch (type) {
+	case BTRFS_EXTENT_DATA_REF_KEY:
+		return COLOR_DATA;
+	case BTRFS_SHARED_BLOCK_REF_KEY:
+	case BTRFS_SHARED_DATA_REF_KEY:
+		return COLOR_FS;
+	case BTRFS_TREE_BLOCK_REF_KEY:
+		break;
+	default:
+		return COLOR_UNKNOWN;
+	}
+
+	switch (offset) {
+	case BTRFS_ROOT_TREE_OBJECTID:
+		return COLOR_ROOT;
+	case BTRFS_EXTENT_TREE_OBJECTID:
+		return COLOR_EXTENT;
+	case BTRFS_CHUNK_TREE_OBJECTID:
+		return COLOR_CHUNK;
+	case BTRFS_DEV_TREE_OBJECTID:
+		return COLOR_DEV;
+	case BTRFS_FS_TREE_OBJECTID:
+		return COLOR_FS;
+	case BTRFS_CSUM_TREE_OBJECTID:
+		return COLOR_CSUM;
+	case BTRFS_DATA_RELOC_TREE_OBJECTID:
+		return COLOR_RELOC;
+	}
+
+	return COLOR_UNKNOWN;
+}
+
+static void
+init_colors(gdImagePtr im, int *colors)
+{
+	colors[COLOR_ROOT] = gdImageColorAllocate(im, 255, 0, 0);
+	colors[COLOR_EXTENT] = gdImageColorAllocate(im, 0, 255, 0);
+	colors[COLOR_CHUNK] = gdImageColorAllocate(im, 255, 0, 0);
+	colors[COLOR_DEV] = gdImageColorAllocate(im, 255, 0, 0);
+	colors[COLOR_FS] = gdImageColorAllocate(im, 0, 0, 0);
+	colors[COLOR_CSUM] = gdImageColorAllocate(im, 0, 0, 255);
+	colors[COLOR_RELOC] = gdImageColorAllocate(im, 128, 128, 128);
+	colors[COLOR_DATA] = gdImageColorAllocate(im, 100, 0, 0);
+	colors[COLOR_UNKNOWN] = gdImageColorAllocate(im, 50, 50, 50);
+}
+
+int
+list_fragments(int fd, u64 flags, char *dir)
+{
+	int ret;
+	struct btrfs_ioctl_search_args args;
+	struct btrfs_ioctl_search_key *sk = &args.key;
+	int i;
+	struct btrfs_ioctl_search_header *sh;
+	unsigned long off = 0;
+	int bgnum = 0;
+	u64 bgstart = 0;
+	u64 bglen = 0;
+	u64 bgend = 0;
+	u64 bgflags = 0;
+	u64 bgused = 0;
+	u64 saved_extent = 0;
+	u64 saved_len = 0;
+	u64 saved_flags = 0;
+	int saved_color = 0;
+	u64 last_end = 0;
+	u64 areas = 0;
+	long px;
+	char name[1000];
+	FILE *html;
+	int colors[COLOR_MAX];
+
+	gdImagePtr im = NULL;
+	int black = 0;
+	int white = 0;
+	int width = 800;
+
+	snprintf(name, sizeof(name), "%s/index.html", dir);
+	html = fopen(name, "w");
+	if (!html) {
+		printf("unable to create %s\n", name);
+		exit(1);
+	}
+
+	fprintf(html, "<html><header>\n");
+	fprintf(html, "<title>Btrfs Block Group Allocation Map</title>\n");
+	fprintf(html, "<style type=\"text/css\">\n");
+	fprintf(html, "img {margin-left: 1em; margin-bottom: 2em;}\n");
+	fprintf(html, "</style>\n");
+	fprintf(html, "</header><body>\n");
+	
+	memset(&args, 0, sizeof(args));
+
+	sk->tree_id = 2;
+	sk->max_type = -1;
+	sk->min_type = 0;
+	sk->max_objectid = (u64)-1;
+	sk->max_offset = (u64)-1;
+	sk->max_transid = (u64)-1;
+
+	/* just a big number, doesn't matter much */
+	sk->nr_items = 4096;
+
+	while(1) {
+		ret = ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args);
+		if (ret < 0) {
+			fprintf(stderr, "ERROR: can't perform the search\n");
+			return ret;
+		}
+		/* the ioctl returns the number of item it found in nr_items */
+		if (sk->nr_items == 0)
+			break;
+
+		off = 0;
+		for (i = 0; i < sk->nr_items; i++) {
+			int j;
+
+			sh = (struct btrfs_ioctl_search_header *)(args.buf +
+								  off);
+			off += sizeof(*sh);
+			if (sh->type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
+				struct btrfs_block_group_item *bg;
+
+				if (im) {
+					push_im(im, name, dir);
+					im = NULL;
+
+					print_bg(html, name, bgstart, bglen,
+						bgused, bgflags, areas);
+				}
+
+				++bgnum;
+
+				bg = (struct btrfs_block_group_item *)
+						(args.buf + off);
+				bgflags = btrfs_block_group_flags(bg);
+				bgused = btrfs_block_group_used(bg);
+				
+				printf("found block group %lld len %lld "
+					"flags %lld\n", sh->objectid,
+					sh->offset, bgflags);
+				if (!(bgflags & flags)) {
+					/* skip this block group */
+					sk->min_objectid = sh->objectid +
+							   sh->offset;
+					sk->min_type = 0;
+					sk->min_offset = 0;
+					break;
+				}
+				im = gdImageCreate(width,
+					(sh->offset / 4096 + 799) / width);
+
+				white = gdImageColorAllocate(im, 255, 255, 255);
+				black = gdImageColorAllocate(im, 0, 0, 0);  
+
+				for (j = 0; j < 10; ++j)
+					colors[j] = black;
+
+				init_colors(im, colors);
+				bgstart = sh->objectid;
+				bglen = sh->offset;
+				bgend = bgstart + bglen;
+
+				snprintf(name, sizeof(name), "bg%d.png", bgnum);
+
+				last_end = bgstart;
+				if (saved_len) {
+					px = (saved_extent - bgstart) / 4096;
+					for (j = 0; j < saved_len / 4096; ++j) {
+						int x = (px + j) % width;
+						int y = (px + j) / width;
+						gdImageSetPixel(im, x, y,
+								saved_color);
+					}
+					last_end += saved_len;
+				}
+				areas = 0;
+				saved_len = 0;
+			}
+			if (im && sh->type == BTRFS_EXTENT_ITEM_KEY) {
+				u64 e_flags;
+				int c;
+				struct btrfs_extent_item *item;
+
+				item = (struct btrfs_extent_item *)
+						(args.buf + off);
+				e_flags = btrfs_stack_extent_flags(item);
+
+				if (use_color)
+					c = colors[get_color(item, sh->len)];
+				else
+					c = black;
+				if (sh->objectid > bgend) {
+					printf("WARN: extent %lld is without "
+						"block group\n", sh->objectid);
+					goto skip;
+				}
+				if (sh->objectid == bgend) {
+					saved_extent = sh->objectid;
+					saved_len = sh->offset;
+					saved_flags = e_flags;
+					saved_color = c;
+					goto skip;
+				}
+				px = (sh->objectid - bgstart) / 4096;
+				for (j = 0; j < sh->offset / 4096; ++j) {
+					int x = (px + j) % width;
+					int y = (px + j) / width;
+					gdImageSetPixel(im, x, y, c);
+				}
+				if (sh->objectid != last_end)
+					++areas;
+				last_end = sh->objectid + sh->offset;
+skip:;
+			}
+			off += sh->len;
+
+			/*
+			 * record the mins in sk so we can make sure the
+			 * next search doesn't repeat this root
+			 */
+			sk->min_objectid = sh->objectid;
+			sk->min_type = sh->type;
+			sk->min_offset = sh->offset;
+		}
+		sk->nr_items = 4096;
+
+		/* increment by one */
+		if (++sk->min_offset == 0)
+			if (++sk->min_type == 0)
+				if (++sk->min_objectid == 0)
+					break;
+	}
+
+	if (im) {
+		push_im(im, name, dir);
+		print_bg(html, name, bgstart, bglen, bgused, bgflags, areas);
+	}
+
+	if (use_color) {
+		fprintf(html, "<p>");
+		fprintf(html, "data - dark red, ");
+		fprintf(html, "fs tree - black, ");
+		fprintf(html, "extent tree - green, ");
+		fprintf(html, "csum tree - blue, ");
+		fprintf(html, "reloc tree - grey, ");
+		fprintf(html, "other trees - red, ");
+		fprintf(html, "unknown tree - dark grey");
+		fprintf(html, "</p>");
+	}
+	fprintf(html, "</body></html>\n");
+	
+	return ret;
+}
+
+void
+usage(void)
+{
+	printf("usage: btrfs-fragments [options] <path>\n");
+	printf("         -c               use color\n");
+	printf("         -d               print data chunks\n");
+	printf("         -m               print metadata chunks\n");
+	printf("         -s               print system chunks\n");
+	printf("                          (default is data+metadata)\n");
+	printf("         -o <dir>         output directory, default is html\n");
+	exit(1);
+}
+
+int main(int argc, char **argv)
+{
+	char *path;
+	int fd;
+	int ret;
+	u64 flags = 0;
+	char *dir = "html";
+
+	while (1) {
+		int c = getopt(argc, argv, "cmso:h");
+		if (c < 0)
+			break;
+		switch (c) {
+		case 'c':
+			use_color = 1;
+			break;
+		case 'd':
+			flags |= BTRFS_BLOCK_GROUP_DATA;
+			break;
+		case 'm':
+			flags |= BTRFS_BLOCK_GROUP_METADATA;
+			break;
+		case 's':
+			flags |= BTRFS_BLOCK_GROUP_SYSTEM;
+			break;
+		case 'o':
+			dir = optarg;
+			break;
+		case 'h':
+		default:
+			usage();
+		}
+	}
+
+	if (optind < argc) {
+		path = argv[optind++];
+	} else {
+		usage();
+		exit(1);
+	}
+
+	fd = open_file_or_dir(path);
+	if (fd < 0) {
+		fprintf(stderr, "ERROR: can't access '%s'\n", path);
+		exit(1);
+	}
+
+	if (flags == 0)
+		flags = BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA;
+
+	ret = list_fragments(fd, flags, dir);
+	if (ret)
+		exit(1);
+
+	exit(0);
+}