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Message-Id: <20061222193049sho@rifu.tnes.nec.co.jp>
Date: Fri, 22 Dec 2006 19:30:49 +0900
From: sho@...s.nec.co.jp
To: linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: [RFC][PATCH 3/3] Online defrag command
The defrag command.
o Defrag for a file.
# e4defrag file-name
o Defrag for all files on whole ext4.
# e4defrag device-name
Signed-off-by: Takashi Sato <sho@...s.nec.co.jp>
---
/*
* e4defrag, ext4 filesystem defragmenter
*
*/
#ifndef _LARGEFILE_SOURCE
#define _LARGEFILE_SOURCE
#endif
#ifndef _LARGEFILE64_SOURCE
#define _LARGEFILE64_SOURCE
#endif
#define _XOPEN_SOURCE 500
#include <ftw.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <dirent.h>
#include <limits.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <sys/statfs.h>
#include <sys/vfs.h>
#include <sys/ioctl.h>
#include <mntent.h>
#define EXT4_SUPER_MAGIC 0xEF53 /* magic number for ext4 */
#define DEFRAG_PAGES 128 /* the number of pages to defrag at one time */
#define MAX_BLOCKS_LEN 16384 /* Maximum length of contiguous blocks */
/* ioctl command */
#define EXT4_IOC_DEFRAG _IOW('f', 9, struct ext4_ext_defrag_data)
#define DEVNAME 0
#define DIRNAME 1
#define FILENAME 2
#define RETURN_OK 0
#define RETURN_NG -1
#define FTW_CONT 0
#define FTW_STOP -1
#define FTW_OPEN_FD 2000
#define FILE_CHK_OK 0
#define FILE_CHK_NG -1
#define FS_EXT4 "ext4dev"
#define ROOT_UID 0
/* defrag block size, in bytes */
#define DEFRAG_SIZE 67108864
#define min(x,y) (((x) > (y)) ? (y) : (x))
#define PRINT_ERR_MSG(msg) fprintf(stderr, "%s\n", (msg));
#define PRINT_FILE_NAME(file) \
fprintf(stderr, "\t\t \"%s\"\n", (file));
#define MSG_USAGE \
"Usage : e4defrag [-v] filename...| dirname...| devname....\n"
#define NGMSG_MTAB \
"\te4defrag : Can not access /etc/mtab."
#define NGMSG_UNMOUNT "\te4defrag : FS is not mounted."
#define NGMSG_EXT4 \
"\te4defrag : FS is not ext4 File System."
#define NGMSG_FS_INFO "\te4defrag : get FSInfo fail."
#define NGMSG_FILE_INFO "\te4defrag : get FileInfo fail."
#define NGMSG_FILE_OPEN "\te4defrag : open fail."
#define NGMSG_FILE_SYNC "\te4defrag : sync(fsync) fail."
#define NGMSG_FILE_DEFRAG "\te4defrag : defrag fail."
#define NGMSG_FILE_UNREG \
"\te4defrag : File is not regular file."
#define NGMSG_FILE_LARGE \
"\te4defrag : Defrag size is larger than FileSystem's free space."
#define NGMSG_FILE_PRIORITY \
"\te4defrag : File is not current user's file or current user is not root."
#define NGMSG_FILE_LOCK "\te4defrag : File is locked."
#define NGMSG_FILE_BLANK "\te4defrag : File size is 0."
#define NGMSG_GET_LCKINFO "\te4defrag : get LockInfo fail."
#define NGMSG_TYPE \
"e4defrag : Can not process %s."
struct ext4_ext_defrag_data {
loff_t start_offset; /* start offset to defrag in bytes */
loff_t defrag_size; /* size of defrag in bytes */
};
int detail_flag = 0;
int amount_cnt = 0;
int succeed_cnt = 0;
/*
* Check if there's enough disk space
*/
int
check_free_size(int fd, off64_t fsize)
{
struct statfs fsbuf;
off64_t file_asize = 0;
if (-1 == fstatfs(fd, &fsbuf)) {
if (detail_flag) {
perror(NGMSG_FS_INFO);
}
return RETURN_NG;
}
/* compute free space for root and normal user separately */
if (ROOT_UID == getuid())
file_asize = (off64_t)fsbuf.f_bsize * fsbuf.f_bfree;
else
file_asize = (off64_t)fsbuf.f_bsize * fsbuf.f_bavail;
if (file_asize >= fsize)
return RETURN_OK;
return RETURN_NG;
}
/*
* file tree walk callback function
* check file attributes before ioctl call to avoid illegal operations
*/
int
ftw_fn(
const char* file,
const struct stat64 *sb,
int flag,
struct FTW* ftwbuf
)
{
int fd;
int defraged_size;
struct ext4_ext_defrag_data df_data;
if (FTW_F == flag) {
amount_cnt++;
if (-1 == (fd = open64(file, O_RDONLY))) {
if (detail_flag) {
perror(NGMSG_FILE_OPEN);
PRINT_FILE_NAME(file);
}
return FTW_CONT;
}
if (FILE_CHK_NG == file_check(fd, sb, file)) {
close(fd);
return FTW_CONT;
}
if (-1 == fsync(fd)) {
if (detail_flag) {
perror(NGMSG_FILE_SYNC);
PRINT_FILE_NAME(file);
}
close(fd);
return FTW_CONT;
}
/* ioctl call does the actual defragment job. */
df_data.start_offset = 0;
while (1) {
df_data.defrag_size =
min((sb->st_size - df_data.start_offset),
DEFRAG_SIZE);
/* EXT4_IOC_DEFRAG */
defraged_size = ioctl(fd, EXT4_IOC_DEFRAG, &df_data);
if (defraged_size == -1) {
if (detail_flag) {
perror(NGMSG_FILE_DEFRAG);
PRINT_FILE_NAME(file);
}
close(fd);
return FTW_CONT;
}
df_data.start_offset += defraged_size;
/* end of file */
if (df_data.start_offset >= sb->st_size) {
break;
}
}
close(fd);
succeed_cnt++;
} else {
if (detail_flag) {
PRINT_ERR_MSG(NGMSG_FILE_UNREG);
PRINT_FILE_NAME(file);
}
}
return FTW_CONT;
}
/*
* check file's attributes
*/
int
file_check(int fd, const struct stat64 * buf, const char * file_name)
{
struct flock lock;
lock.l_type = F_WRLCK; /* write-lock check is more reliable. */
lock.l_start = 0;
lock.l_whence = SEEK_SET;
lock.l_len = 0;
/* regular file */
if (0 == S_ISREG(buf->st_mode)) {
if (detail_flag) {
PRINT_ERR_MSG(NGMSG_FILE_UNREG);
PRINT_FILE_NAME(file_name);
}
return FILE_CHK_NG;
}
/* available space */
if (RETURN_NG == check_free_size(fd, DEFRAG_SIZE)) {
if (detail_flag) {
PRINT_ERR_MSG(NGMSG_FILE_LARGE);
PRINT_FILE_NAME(file_name);
}
return FILE_CHK_NG;
}
/* priority */
if (ROOT_UID != getuid() &&
buf->st_uid != getuid()) {
if (detail_flag) {
PRINT_ERR_MSG(NGMSG_FILE_PRIORITY);
PRINT_FILE_NAME(file_name);
}
return FILE_CHK_NG;
}
/* lock status */
if (-1 == fcntl(fd, F_GETLK, &lock)) {
if (detail_flag) {
perror(NGMSG_GET_LCKINFO);
PRINT_FILE_NAME(file_name);
}
return FILE_CHK_NG;
} else if (F_UNLCK != lock.l_type) {
if (detail_flag) {
PRINT_ERR_MSG(NGMSG_FILE_LOCK);
PRINT_FILE_NAME(file_name);
}
return FILE_CHK_NG;
}
/* empty file */
if (buf->st_size == 0) {
if (detail_flag) {
PRINT_ERR_MSG(NGMSG_FILE_BLANK);
PRINT_FILE_NAME(file_name);
}
return FILE_CHK_NG;
}
return FILE_CHK_OK;
}
/*
* whether on an ext4 filesystem
*/
int
is_ext4(const char * filename)
{
struct statfs buffs;
if (-1 == statfs(filename, &buffs)) {
perror(NGMSG_FS_INFO);
PRINT_FILE_NAME(filename);
return RETURN_NG;
} else if (EXT4_SUPER_MAGIC == buffs.f_type) {
return RETURN_OK;
} else {
PRINT_ERR_MSG(NGMSG_EXT4);
return RETURN_NG;
}
}
/*
* Get device's mount point
*/
int
get_mount_point(const char * devname, char * mount_point, int buf_len)
{
char * mtab = MOUNTED; /* refer to /etc/mtab */
struct mntent * mnt = NULL;
FILE * fp = NULL;
if (NULL == (fp = setmntent(mtab, "r"))) {
perror(NGMSG_MTAB);
return RETURN_NG;
}
while ((mnt = getmntent(fp)) != NULL) {
if (strcmp(devname, mnt->mnt_fsname) == 0) {
endmntent(fp);
if (strcmp(mnt->mnt_type, FS_EXT4) == 0) {
strncpy(mount_point, mnt->mnt_dir, buf_len);
return RETURN_OK;
}
PRINT_ERR_MSG(NGMSG_EXT4);
return RETURN_NG;
}
}
endmntent(fp);
PRINT_ERR_MSG(NGMSG_UNMOUNT);
return RETURN_NG;
}
int
main(
int argc,
char* argv[]
)
{
int i, flags;
int arg_type;
int success_flag;
int orig_detail;
char dir_name[PATH_MAX];
struct stat64 buf;
i = 1;
arg_type = -1;
success_flag = 0;
orig_detail = -1;
flags = 0;
flags |= FTW_PHYS; /* do not follow symlink */
flags |= FTW_MOUNT; /* stay within the same filesystem */
/* parse arguments */
if (argc == 1 || (argc == 2 && argv[1][0] == '-') ||
(argc > 2 && argv[1][0] == '-' && strcmp(argv[1], "-v") != 0)) {
printf(MSG_USAGE);
return 1;
}
if (0 == strcmp(argv[1], "-v")) {
detail_flag = 1;
i = 2;
}
/* main process */
for (; i < argc; i++) {
amount_cnt = 0;
succeed_cnt = 0;
memset(dir_name, 0, PATH_MAX);
if (-1 == stat64(argv[i], &buf)) {
perror(NGMSG_FILE_INFO);
PRINT_FILE_NAME(argv[i]);
continue;
}
/* block device */
if (S_ISBLK(buf.st_mode)) {
arg_type = DEVNAME;
if (RETURN_NG ==
get_mount_point(argv[i], dir_name, PATH_MAX)) {
continue;
}
printf("Start defragment for device(%s)\n", argv[i]);
} else if (S_ISDIR(buf.st_mode)) {
/* directory */
arg_type = DIRNAME;
if (-1 == access(argv[i], R_OK)) {
perror(argv[i]);
continue;
}
strcpy(dir_name, argv[i]);
} else if (S_ISREG(buf.st_mode)) {
/* regular file */
arg_type = FILENAME;
} else {
/* irregular file */
PRINT_ERR_MSG(NGMSG_FILE_UNREG);
PRINT_FILE_NAME(argv[i]);
continue;
}
/* device's ext4 check is in get_mount_point() */
if (arg_type == FILENAME || arg_type == DIRNAME) {
if (RETURN_NG == is_ext4(argv[i])) {
continue;
}
}
switch (arg_type) {
case DIRNAME:
printf("Start defragment for directory(%s)\n",
argv[i]);
case DEVNAME:
/* file tree walk */
nftw64(dir_name, ftw_fn, FTW_OPEN_FD, flags);
printf("\tTotal:\t\t%12d\n", amount_cnt);
printf("\tSuccess:\t%12d\n", succeed_cnt);
printf("\tFailure:\t%12d\n",
amount_cnt - succeed_cnt);
break;
case FILENAME:
orig_detail = detail_flag;
detail_flag = 1;
printf("Start defragment for %s\n", argv[i]);
/* single file process */
ftw_fn(argv[i], &buf, FTW_F, NULL);
if (succeed_cnt != 0) {
printf(
"\tSUCCESS\t:file defrag success.\n"
);
}
detail_flag = orig_detail;
break;
}
if (succeed_cnt != 0)
success_flag = 1;
}
if (success_flag)
return 0;
return 1;
}
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