e2freefrag.c revision 137a7dc05c80cd4e0a4e7aeb21ec79f800a9eecd 
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_chunks[i] = 0;
65		info->histogram.fc_blocks[i] = 0;
66	}
67}
68
69void scan_block_bitmap(ext2_filsys fs, struct chunk_info *info)
70{
71	unsigned long long blocks_count = fs->super->s_blocks_count;
72	unsigned long long chunks = (blocks_count + info->blks_in_chunk) >>
73				(info->chunkbits - info->blocksize_bits);
74	unsigned long long chunk_num;
75	unsigned long last_chunk_size = 0;
76	unsigned long long chunk_start_blk = 0;
77
78	for (chunk_num = 0; chunk_num < chunks; chunk_num++) {
79		unsigned long long blk, num_blks;
80		int chunk_free;
81
82		/* Last chunk may be smaller */
83		if (chunk_start_blk + info->blks_in_chunk > blocks_count)
84			num_blks = blocks_count - chunk_start_blk;
85		else
86			num_blks = info->blks_in_chunk;
87
88		chunk_free = 0;
89
90		/* Initialize starting block for first chunk correctly else
91		 * there is a segfault when blocksize = 1024 in which case
92		 * block_map->start = 1 */
93		for (blk = (chunk_num == 0 ? fs->super->s_first_data_block : 0);
94		     blk < num_blks; blk++, chunk_start_blk++) {
95			int used = ext2fs_fast_test_block_bitmap(fs->block_map,
96							       chunk_start_blk);
97			if (!used) {
98				last_chunk_size++;
99				chunk_free++;
100			}
101
102			if (used && last_chunk_size != 0) {
103				unsigned long index;
104
105				index = ul_log2(last_chunk_size) + 1;
106				info->histogram.fc_chunks[index]++;
107				info->histogram.fc_blocks[index] +=
108							last_chunk_size;
109
110				if (last_chunk_size > info->max)
111					info->max = last_chunk_size;
112				if (last_chunk_size < info->min)
113					info->min = last_chunk_size;
114				info->avg += last_chunk_size;
115
116				info->real_free_chunks++;
117				last_chunk_size = 0;
118			}
119		}
120
121		if (chunk_free == info->blks_in_chunk)
122			info->free_chunks++;
123	}
124}
125
126errcode_t get_chunk_info(ext2_filsys fs, struct chunk_info *info)
127{
128	unsigned long total_chunks;
129	char *unitp = "KMGTPEZY";
130	int units = 10;
131	unsigned long start = 0, end, cum;
132	int i, retval = 0;
133
134	scan_block_bitmap(fs, info);
135
136	printf("Total blocks: %u\nFree blocks: %u (%0.1f%%)\n",
137	       fs->super->s_blocks_count, fs->super->s_free_blocks_count,
138	       (double)fs->super->s_free_blocks_count * 100 /
139						fs->super->s_blocks_count);
140
141	printf("\nChunksize: %lu bytes (%u blocks)\n",
142	       info->chunkbytes, info->blks_in_chunk);
143	total_chunks = (fs->super->s_blocks_count + info->blks_in_chunk) >>
144				(info->chunkbits - info->blocksize_bits);
145	printf("Total chunks: %lu\nFree chunks: %lu (%0.1f%%)\n",
146	       total_chunks, info->free_chunks,
147	       (double)info->free_chunks * 100 / total_chunks);
148
149	/* Display chunk information in KB */
150	if (info->real_free_chunks) {
151		info->min = (info->min * fs->blocksize) >> 10;
152		info->max = (info->max * fs->blocksize) >> 10;
153		info->avg = (info->avg / info->real_free_chunks *
154			     fs->blocksize) >> 10;
155	} else {
156		info->min = 0;
157	}
158
159	printf("\nMin free chunk: %lu KB \nMax free chunk: %lu KB\n"
160	       "Avg free chunk: %lu KB\n", info->min, info->max, info->avg);
161
162	printf("\nHISTOGRAM OF FREE CHUNK SIZES:\n");
163	printf("%s :  %12s  %12s  %7s\n", "Chunk Size Range", "Free chunks",
164	       "Free Blocks", "Percent");
165	for (i = 0; i < MAX_HIST; i++) {
166		end = 1 << (i + info->blocksize_bits - units);
167		if (info->histogram.fc_chunks[i] != 0)
168			printf("%5lu%c...%5lu%c- :  %12lu  %12lu  %6.2f%%\n",
169			       start, *unitp, end, *unitp,
170			       info->histogram.fc_chunks[i],
171			       info->histogram.fc_blocks[i],
172			       (double)info->histogram.fc_blocks[i] * 100 /
173			       fs->super->s_free_blocks_count);
174		start = end;
175		if (start == 1<<10) {
176			start = 1;
177			units += 10;
178			unitp++;
179		}
180	}
181
182	return retval;
183}
184
185void close_device(char *device_name, ext2_filsys fs)
186{
187	int retval = ext2fs_close(fs);
188
189	if (retval)
190		com_err(device_name, retval, "while closing the filesystem.\n");
191}
192
193void collect_info(ext2_filsys fs, struct chunk_info *chunk_info)
194{
195	unsigned int retval = 0, i, free_blks;
196
197	printf("Device: %s\n", fs->device_name);
198	printf("Blocksize: %u bytes\n", fs->blocksize);
199
200	retval = ext2fs_read_block_bitmap(fs);
201	if (retval) {
202		com_err(fs->device_name, retval, "while reading block bitmap");
203		close_device(fs->device_name, fs);
204		exit(1);
205	}
206
207	init_chunk_info(fs, chunk_info);
208
209	retval = get_chunk_info(fs, chunk_info);
210	if (retval) {
211		com_err(fs->device_name, retval, "while collecting chunk info");
212                close_device(fs->device_name, fs);
213		exit(1);
214	}
215}
216
217void open_device(char *device_name, ext2_filsys *fs)
218{
219	int retval;
220	int flag = EXT2_FLAG_FORCE;
221
222	retval = ext2fs_open(device_name, flag, 0, 0, unix_io_manager, fs);
223	if (retval) {
224		com_err(device_name, retval, "while opening filesystem");
225		exit(1);
226	}
227}
228
229int main(int argc, char *argv[])
230{
231	struct chunk_info chunk_info = { .chunkbytes = DEFAULT_CHUNKSIZE };
232	errcode_t retval = 0;
233	ext2_filsys fs = NULL;
234	char *device_name;
235	char *progname;
236	char c, *end;
237
238	add_error_table(&et_ext2_error_table);
239	progname = argv[0];
240
241	while ((c = getopt(argc, argv, "c:h")) != EOF) {
242		switch (c) {
243		case 'c':
244			chunk_info.chunkbytes = strtoull(optarg, &end, 0);
245			if (*end != '\0') {
246				fprintf(stderr, "%s: bad chunk size '%s'\n",
247					progname, optarg);
248				usage(progname);
249			}
250			if (chunk_info.chunkbytes &
251			    (chunk_info.chunkbytes - 1)) {
252				fprintf(stderr, "%s: chunk size must be a "
253					"power of 2.", argv[0]);
254				usage(progname);
255			}
256			chunk_info.chunkbytes *= 1024;
257			break;
258		default:
259			fprintf(stderr, "%s: bad option '%c'\n",
260				progname, c);
261		case 'h':
262			usage(progname);
263			break;
264		}
265	}
266
267	if (optind == argc) {
268		fprintf(stderr, "%s: missing device name.\n", progname);
269		usage(progname);
270	}
271
272	device_name = argv[optind];
273
274	open_device(device_name, &fs);
275
276	if (chunk_info.chunkbytes < fs->blocksize) {
277		fprintf(stderr, "%s: chunksize must be greater than or equal "
278			"to filesystem blocksize.\n", progname);
279		exit(1);
280	}
281	collect_info(fs, &chunk_info);
282	close_device(device_name, fs);
283
284	return retval;
285}
286