e2freefrag.c revision 0b2681f45b7f67eedfea6411eddbb858699ae553 
1/*
2 * e2freefrag - report filesystem free-space fragmentation
3 *
4 * Copyright (C) 2009 Sun Microsystems, Inc.
5 *
6 * Author: Rupesh Thakare <rupesh@sun.com>
7 *         Andreas Dilger <adilger@sun.com>
8 *
9 * %Begin-Header%
10 * This file may be redistributed under the terms of the GNU Public
11 * License version 2.
12 * %End-Header%
13 */
14#include <stdio.h>
15#ifdef HAVE_UNISTD_H
16#include <unistd.h>
17#endif
18#ifdef HAVE_STDLIB_H
19#include <stdlib.h>
20#endif
21#ifdef HAVE_GETOPT_H
22#include <getopt.h>
23#else
24extern char *optarg;
25extern int optind;
26#endif
27
28#include "ext2fs/ext2_fs.h"
29#include "ext2fs/ext2fs.h"
30#include "e2freefrag.h"
31
32void usage(const char *prog)
33{
34	fprintf(stderr, "usage: %s [-c chunksize in kb] [-h] "
35		"device_name\n", prog);
36	exit(1);
37}
38
39static int ul_log2(unsigned long arg)
40{
41        int     l = 0;
42
43        arg >>= 1;
44        while (arg) {
45                l++;
46                arg >>= 1;
47        }
48        return l;
49}
50
51void init_chunk_info(ext2_filsys fs, struct chunk_info *info)
52{
53	int i;
54
55	info->chunkbits = ul_log2(info->chunkbytes);
56	info->blocksize_bits = ul_log2((unsigned long)fs->blocksize);
57	info->blks_in_chunk = info->chunkbytes >> info->blocksize_bits;
58
59	info->min = ~0UL;
60	info->max = info->avg = 0;
61	info->real_free_chunks = 0;
62
63	for (i = 0; i < MAX_HIST; i++)
64		info->histogram.fc_buckets[i] = 0;
65}
66
67void scan_block_bitmap(ext2_filsys fs, struct chunk_info *info)
68{
69	unsigned long long blocks_count = fs->super->s_blocks_count;
70	unsigned long long chunks = (blocks_count + info->blks_in_chunk) >>
71				(info->chunkbits - info->blocksize_bits);
72	unsigned long long chunk_num;
73	unsigned long last_chunk_size = 0;
74	unsigned long long chunk_start_blk = 0;
75
76	for (chunk_num = 0; chunk_num < chunks; chunk_num++) {
77		unsigned long long blk, num_blks;
78		int chunk_free;
79
80		/* Last chunk may be smaller */
81		if (chunk_start_blk + info->blks_in_chunk > blocks_count)
82			num_blks = blocks_count - chunk_start_blk;
83		else
84			num_blks = info->blks_in_chunk;
85
86		chunk_free = 0;
87
88		/* Initialize starting block for first chunk correctly else
89		 * there is a segfault when blocksize = 1024 in which case
90		 * block_map->start = 1 */
91		for (blk = (chunk_num == 0 ? fs->super->s_first_data_block : 0);
92		     blk < num_blks; blk++, chunk_start_blk++) {
93			int used = ext2fs_fast_test_block_bitmap(fs->block_map,
94							       chunk_start_blk);
95			if (!used) {
96				last_chunk_size++;
97				chunk_free++;
98			}
99
100			if (used && last_chunk_size != 0) {
101				unsigned long index;
102
103				index = ul_log2(last_chunk_size) + 1;
104				info->histogram.fc_buckets[index]++;
105
106				if (last_chunk_size > info->max)
107					info->max = last_chunk_size;
108				if (last_chunk_size < info->min)
109					info->min = last_chunk_size;
110				info->avg += last_chunk_size;
111
112				info->real_free_chunks++;
113				last_chunk_size = 0;
114			}
115		}
116
117		if (chunk_free == info->blks_in_chunk)
118			info->free_chunks++;
119	}
120}
121
122errcode_t get_chunk_info(ext2_filsys fs, struct chunk_info *info)
123{
124	unsigned long total_chunks;
125	char *unitp = "KMGTPEZY";
126	int units = 10;
127	unsigned long start = 0, end, cum;
128	int i, retval = 0;
129
130	scan_block_bitmap(fs, info);
131
132	printf("Total blocks: %u\nFree blocks: %u (%0.1f%%)\n",
133	       fs->super->s_blocks_count, fs->super->s_free_blocks_count,
134	       (double)fs->super->s_free_blocks_count * 100 /
135						fs->super->s_blocks_count);
136
137	printf("\nChunksize: %lu bytes (%u blocks)\n",
138	       info->chunkbytes, info->blks_in_chunk);
139	total_chunks = (fs->super->s_blocks_count + info->blks_in_chunk) >>
140                                       (info->chunkbits - info->blocksize_bits);
141	printf("Total chunks: %lu\nFree chunks: %lu (%0.1f%%)\n",
142	       total_chunks, info->free_chunks,
143	       (double)info->free_chunks * 100 / total_chunks);
144
145	/* Display chunk information in KB */
146	if (info->real_free_chunks) {
147		info->min = (info->min * fs->blocksize) >> 10;
148		info->max = (info->max * fs->blocksize) >> 10;
149		info->avg = (info->avg / info->real_free_chunks *
150			     fs->blocksize) >> 10;
151	} else {
152		info->min = 0;
153	}
154
155	printf("\nMin free chunk: %lu KB \nMax free chunk: %lu KB\n"
156	       "Avg free chunk: %lu KB\n", info->min, info->max, info->avg);
157
158	printf("\nHISTOGRAM OF FREE CHUNK SIZES:\n");
159	printf("%s\t%10s\n", "Chunk Size Range :", "Free chunks");
160	for (i = 0; i < MAX_HIST; i++) {
161		end = 1 << (i + info->blocksize_bits - units);
162		if (info->histogram.fc_buckets[i] != 0)
163			printf("%5lu%c...%5lu%c- :  %10lu\n", start, *unitp,
164			       end, *unitp, info->histogram.fc_buckets[i]);
165		start = end;
166		if (start == 1<<10) {
167			start = 1;
168			units += 10;
169			unitp++;
170		}
171	}
172
173	return retval;
174}
175
176void close_device(char *device_name, ext2_filsys fs)
177{
178	int retval = ext2fs_close(fs);
179
180	if (retval)
181		com_err(device_name, retval, "while closing the filesystem.\n");
182}
183
184void collect_info(ext2_filsys fs, struct chunk_info *chunk_info)
185{
186	unsigned int retval = 0, i, free_blks;
187
188	printf("Device: %s\n", fs->device_name);
189	printf("Blocksize: %u bytes\n", fs->blocksize);
190
191	retval = ext2fs_read_block_bitmap(fs);
192	if (retval) {
193		com_err(fs->device_name, retval, "while reading block bitmap");
194		close_device(fs->device_name, fs);
195		exit(1);
196	}
197
198	init_chunk_info(fs, chunk_info);
199
200	retval = get_chunk_info(fs, chunk_info);
201	if (retval) {
202		com_err(fs->device_name, retval, "while collecting chunk info");
203                close_device(fs->device_name, fs);
204		exit(1);
205	}
206}
207
208void open_device(char *device_name, ext2_filsys *fs)
209{
210	int retval;
211	int flag = EXT2_FLAG_FORCE;
212
213	retval = ext2fs_open(device_name, flag, 0, 0, unix_io_manager, fs);
214	if (retval) {
215		com_err(device_name, retval, "while opening filesystem");
216		exit(1);
217	}
218}
219
220int main(int argc, char *argv[])
221{
222	struct chunk_info chunk_info = { .chunkbytes = DEFAULT_CHUNKSIZE };
223	errcode_t retval = 0;
224	ext2_filsys fs = NULL;
225	char *device_name;
226	char *progname;
227	char c, *end;
228
229	progname = argv[0];
230
231	while ((c = getopt(argc, argv, "c:h")) != EOF) {
232		switch (c) {
233		case 'c':
234			chunk_info.chunkbytes = strtoull(optarg, &end, 0);
235			if (*end != '\0') {
236				fprintf(stderr, "%s: bad chunk size '%s'\n",
237					progname, optarg);
238				usage(progname);
239			}
240			if (chunk_info.chunkbytes &
241			    (chunk_info.chunkbytes - 1)) {
242				fprintf(stderr, "%s: chunk size must be a "
243					"power of 2.", argv[0]);
244				usage(progname);
245			}
246			chunk_info.chunkbytes *= 1024;
247			break;
248		default:
249			fprintf(stderr, "%s: bad option '%c'\n",
250				progname, c);
251		case 'h':
252			usage(progname);
253			break;
254		}
255	}
256
257	if (optind == argc) {
258		fprintf(stderr, "%s: missing device name.\n", progname);
259		usage(progname);
260	}
261
262	device_name = argv[optind];
263
264	open_device(device_name, &fs);
265
266	if (chunk_info.chunkbytes < fs->blocksize) {
267		fprintf(stderr, "%s: chunksize must be greater than or equal "
268			"to filesystem blocksize.\n", progname);
269		exit(1);
270	}
271	collect_info(fs, &chunk_info);
272	close_device(device_name, fs);
273
274	return retval;
275}
276