Currently, e4defrag will not work on machines where /etc/mtab is not present
OR is empty.
This patch does 3 things:
a) Add option "-m mtab" to e4defrag so that user can specify any file to
be scanned for otbtaining mounted filesystems info.
b) If mtab option is not specified, first we try to scan /proc/mounts, if failed
to access this file, we try with /etc/mtab.
c) In function is_ext4, check if the varibale "mnt_type" is null before
calling strcmp, otherwise segfault would occur if mtab is empty.
Signed-off-by: Ashish Sangwan <[email protected]>
Signed-off-by: Namjae Jeon <[email protected]>
---
misc/e4defrag.8.in | 10 ++++++++++
misc/e4defrag.c | 34 ++++++++++++++++++++++------------
2 files changed, 32 insertions(+), 12 deletions(-)
diff --git a/misc/e4defrag.8.in b/misc/e4defrag.8.in
index 75e1bc9..7090e51 100644
--- a/misc/e4defrag.8.in
+++ b/misc/e4defrag.8.in
@@ -9,6 +9,9 @@ e4defrag \- online defragmenter for ext4 filesystem
[
.B \-v
]
+[
+.B \-m mtab
+]
.I target
\&...
.SH DESCRIPTION
@@ -57,6 +60,13 @@ is never defragmented.
.B \-v
Print error messages and the fragmentation count before and after defrag for
each file.
+.TP
+.B \-m mtab
+This option will specify the file to be scanned for obtaining mounted filesystems
+information. If this option is not specified, the default is to use
+.B /proc/mounts .
+If this file is not accessible, e4defrag will try to get required information from
+.B /etc/mtab
.SH NOTES
.B e4defrag
does not support swap file, files in lost+found directory, and files allocated
diff --git a/misc/e4defrag.c b/misc/e4defrag.c
index 4b31d03..3567e9f 100644
--- a/misc/e4defrag.c
+++ b/misc/e4defrag.c
@@ -123,6 +123,7 @@
#define NGMSG_FILE_OPEN "Failed to open"
#define NGMSG_FILE_UNREG "File is not regular file"
#define NGMSG_LOST_FOUND "Can not process \"lost+found\""
+#define _PATH_PROC_MOUNTS "/proc/mounts"
/* Data type for filesystem-wide blocks number */
typedef unsigned long long ext4_fsblk_t;
@@ -262,10 +263,8 @@ static int fallocate64(int fd, int mode, loff_t offset, loff_t len)
* @dir_path_len: the length of directory.
*/
static int get_mount_point(const char *devname, char *mount_point,
- int dir_path_len)
+ int dir_path_len, const char *mtab)
{
- /* Refer to /etc/mtab */
- const char *mtab = MOUNTED;
FILE *fp = NULL;
struct mntent *mnt = NULL;
struct stat64 sb;
@@ -278,7 +277,7 @@ static int get_mount_point(const char *devname, char *mount_point,
fp = setmntent(mtab, "r");
if (fp == NULL) {
- perror("Couldn't access /etc/mtab");
+ printf("Couldn't access %s\n", mtab);
return -1;
}
@@ -313,14 +312,12 @@ static int get_mount_point(const char *devname, char *mount_point,
*
* @file: the file's name.
*/
-static int is_ext4(const char *file, char *devname)
+static int is_ext4(const char *file, char *devname, const char *mtab)
{
int maxlen = 0;
int len, ret;
FILE *fp = NULL;
char *mnt_type = NULL;
- /* Refer to /etc/mtab */
- const char *mtab = MOUNTED;
char file_path[PATH_MAX + 1];
struct mntent *mnt = NULL;
struct statfs64 fsbuf;
@@ -345,7 +342,7 @@ static int is_ext4(const char *file, char *devname)
fp = setmntent(mtab, "r");
if (fp == NULL) {
- perror("Couldn't access /etc/mtab");
+ printf("Couldn't access %s", mtab);
return -1;
}
@@ -374,6 +371,10 @@ static int is_ext4(const char *file, char *devname)
}
endmntent(fp);
+ if (mnt_type == NULL) {
+ printf("Could not get mount information from %s\n", mtab);
+ return -1;
+ }
if (strcmp(mnt_type, FS_EXT4) == 0) {
FREE(mnt_type);
return 0;
@@ -1724,6 +1725,7 @@ int main(int argc, char *argv[])
int success_flag = 0;
char dir_name[PATH_MAX + 1];
char dev_name[PATH_MAX + 1];
+ char *mtab = NULL;
struct stat64 buf;
ext2_filsys fs = NULL;
@@ -1731,7 +1733,7 @@ int main(int argc, char *argv[])
if (argc == 1)
goto out;
- while ((opt = getopt(argc, argv, "vc")) != EOF) {
+ while ((opt = getopt(argc, argv, "vcm:")) != EOF) {
switch (opt) {
case 'v':
mode_flag |= DETAIL;
@@ -1739,11 +1741,19 @@ int main(int argc, char *argv[])
case 'c':
mode_flag |= STATISTIC;
break;
+ case 'm':
+ mtab = optarg;
+ break;
default:
goto out;
}
}
-
+ if (!mtab) {
+ if (access(_PATH_PROC_MOUNTS, R_OK) == 0)
+ mtab = _PATH_PROC_MOUNTS;
+ else
+ mtab = _PATH_MOUNTED;
+ }
if (argc == optind)
goto out;
@@ -1797,7 +1807,7 @@ int main(int argc, char *argv[])
if (S_ISBLK(buf.st_mode)) {
/* Block device */
strncpy(dev_name, argv[i], strnlen(argv[i], PATH_MAX));
- if (get_mount_point(argv[i], dir_name, PATH_MAX) < 0)
+ if (get_mount_point(argv[i], dir_name, PATH_MAX, mtab) < 0)
continue;
if (lstat64(dir_name, &buf) < 0) {
perror(NGMSG_FILE_INFO);
@@ -1833,7 +1843,7 @@ int main(int argc, char *argv[])
* filesystem type checked in get_mount_point()
*/
if (arg_type == FILENAME || arg_type == DIRNAME) {
- if (is_ext4(argv[i], dev_name) < 0)
+ if (is_ext4(argv[i], dev_name, mtab) < 0)
continue;
if (realpath(argv[i], dir_name) == NULL) {
perror("Couldn't get full path");
--
1.7.8.4
On 10/17/12 11:52 AM, Ashish Sangwan wrote:
> Currently, e4defrag will not work on machines where /etc/mtab is not present
> OR is empty.
> This patch does 3 things:
> a) Add option "-m mtab" to e4defrag so that user can specify any file to
> be scanned for otbtaining mounted filesystems info.
Under what conditions would this be useful; i.e. when is mtab information
ever in a file other than /etc/mtab?
Thanks,
-Eric
> b) If mtab option is not specified, first we try to scan /proc/mounts, if failed
> to access this file, we try with /etc/mtab.
> c) In function is_ext4, check if the varibale "mnt_type" is null before
> calling strcmp, otherwise segfault would occur if mtab is empty.
>
> Signed-off-by: Ashish Sangwan <[email protected]>
> Signed-off-by: Namjae Jeon <[email protected]>
> ---
> misc/e4defrag.8.in | 10 ++++++++++
> misc/e4defrag.c | 34 ++++++++++++++++++++++------------
> 2 files changed, 32 insertions(+), 12 deletions(-)
>
> diff --git a/misc/e4defrag.8.in b/misc/e4defrag.8.in
> index 75e1bc9..7090e51 100644
> --- a/misc/e4defrag.8.in
> +++ b/misc/e4defrag.8.in
> @@ -9,6 +9,9 @@ e4defrag \- online defragmenter for ext4 filesystem
> [
> .B \-v
> ]
> +[
> +.B \-m mtab
> +]
> .I target
> \&...
> .SH DESCRIPTION
> @@ -57,6 +60,13 @@ is never defragmented.
> .B \-v
> Print error messages and the fragmentation count before and after defrag for
> each file.
> +.TP
> +.B \-m mtab
> +This option will specify the file to be scanned for obtaining mounted filesystems
> +information. If this option is not specified, the default is to use
> +.B /proc/mounts .
> +If this file is not accessible, e4defrag will try to get required information from
> +.B /etc/mtab
> .SH NOTES
> .B e4defrag
> does not support swap file, files in lost+found directory, and files allocated
> diff --git a/misc/e4defrag.c b/misc/e4defrag.c
> index 4b31d03..3567e9f 100644
> --- a/misc/e4defrag.c
> +++ b/misc/e4defrag.c
> @@ -123,6 +123,7 @@
> #define NGMSG_FILE_OPEN "Failed to open"
> #define NGMSG_FILE_UNREG "File is not regular file"
> #define NGMSG_LOST_FOUND "Can not process \"lost+found\""
> +#define _PATH_PROC_MOUNTS "/proc/mounts"
>
> /* Data type for filesystem-wide blocks number */
> typedef unsigned long long ext4_fsblk_t;
> @@ -262,10 +263,8 @@ static int fallocate64(int fd, int mode, loff_t offset, loff_t len)
> * @dir_path_len: the length of directory.
> */
> static int get_mount_point(const char *devname, char *mount_point,
> - int dir_path_len)
> + int dir_path_len, const char *mtab)
> {
> - /* Refer to /etc/mtab */
> - const char *mtab = MOUNTED;
> FILE *fp = NULL;
> struct mntent *mnt = NULL;
> struct stat64 sb;
> @@ -278,7 +277,7 @@ static int get_mount_point(const char *devname, char *mount_point,
>
> fp = setmntent(mtab, "r");
> if (fp == NULL) {
> - perror("Couldn't access /etc/mtab");
> + printf("Couldn't access %s\n", mtab);
> return -1;
> }
>
> @@ -313,14 +312,12 @@ static int get_mount_point(const char *devname, char *mount_point,
> *
> * @file: the file's name.
> */
> -static int is_ext4(const char *file, char *devname)
> +static int is_ext4(const char *file, char *devname, const char *mtab)
> {
> int maxlen = 0;
> int len, ret;
> FILE *fp = NULL;
> char *mnt_type = NULL;
> - /* Refer to /etc/mtab */
> - const char *mtab = MOUNTED;
> char file_path[PATH_MAX + 1];
> struct mntent *mnt = NULL;
> struct statfs64 fsbuf;
> @@ -345,7 +342,7 @@ static int is_ext4(const char *file, char *devname)
>
> fp = setmntent(mtab, "r");
> if (fp == NULL) {
> - perror("Couldn't access /etc/mtab");
> + printf("Couldn't access %s", mtab);
> return -1;
> }
>
> @@ -374,6 +371,10 @@ static int is_ext4(const char *file, char *devname)
> }
>
> endmntent(fp);
> + if (mnt_type == NULL) {
> + printf("Could not get mount information from %s\n", mtab);
> + return -1;
> + }
> if (strcmp(mnt_type, FS_EXT4) == 0) {
> FREE(mnt_type);
> return 0;
> @@ -1724,6 +1725,7 @@ int main(int argc, char *argv[])
> int success_flag = 0;
> char dir_name[PATH_MAX + 1];
> char dev_name[PATH_MAX + 1];
> + char *mtab = NULL;
> struct stat64 buf;
> ext2_filsys fs = NULL;
>
> @@ -1731,7 +1733,7 @@ int main(int argc, char *argv[])
> if (argc == 1)
> goto out;
>
> - while ((opt = getopt(argc, argv, "vc")) != EOF) {
> + while ((opt = getopt(argc, argv, "vcm:")) != EOF) {
> switch (opt) {
> case 'v':
> mode_flag |= DETAIL;
> @@ -1739,11 +1741,19 @@ int main(int argc, char *argv[])
> case 'c':
> mode_flag |= STATISTIC;
> break;
> + case 'm':
> + mtab = optarg;
> + break;
> default:
> goto out;
> }
> }
> -
> + if (!mtab) {
> + if (access(_PATH_PROC_MOUNTS, R_OK) == 0)
> + mtab = _PATH_PROC_MOUNTS;
> + else
> + mtab = _PATH_MOUNTED;
> + }
> if (argc == optind)
> goto out;
>
> @@ -1797,7 +1807,7 @@ int main(int argc, char *argv[])
> if (S_ISBLK(buf.st_mode)) {
> /* Block device */
> strncpy(dev_name, argv[i], strnlen(argv[i], PATH_MAX));
> - if (get_mount_point(argv[i], dir_name, PATH_MAX) < 0)
> + if (get_mount_point(argv[i], dir_name, PATH_MAX, mtab) < 0)
> continue;
> if (lstat64(dir_name, &buf) < 0) {
> perror(NGMSG_FILE_INFO);
> @@ -1833,7 +1843,7 @@ int main(int argc, char *argv[])
> * filesystem type checked in get_mount_point()
> */
> if (arg_type == FILENAME || arg_type == DIRNAME) {
> - if (is_ext4(argv[i], dev_name) < 0)
> + if (is_ext4(argv[i], dev_name, mtab) < 0)
> continue;
> if (realpath(argv[i], dir_name) == NULL) {
> perror("Couldn't get full path");
>
On Wed, Oct 17, 2012 at 10:36 PM, Eric Sandeen <[email protected]> wrote:
> On 10/17/12 11:52 AM, Ashish Sangwan wrote:
>> Currently, e4defrag will not work on machines where /etc/mtab is not present
>> OR is empty.
>> This patch does 3 things:
>> a) Add option "-m mtab" to e4defrag so that user can specify any file to
>> be scanned for otbtaining mounted filesystems info.
>
> Under what conditions would this be useful; i.e. when is mtab information
> ever in a file other than /etc/mtab?
On embedded systems usually /etc is read-only. In that case /etc/mtab,
though present, is empty.
When we tried to run e4defrag on our system, it gave segfault due to
the reasons mentioned in patch.
Then we look into xfs_fsr and found that it has this -m mtab option
due to which it worked without any problem
on our system. Also, xfs_fsr scans /proc/mounts first. So we changed
e4defrag accordingly.
>
> Thanks,
> -Eric
>
>> b) If mtab option is not specified, first we try to scan /proc/mounts, if failed
>> to access this file, we try with /etc/mtab.
>> c) In function is_ext4, check if the varibale "mnt_type" is null before
>> calling strcmp, otherwise segfault would occur if mtab is empty.
>>
>> Signed-off-by: Ashish Sangwan <[email protected]>
>> Signed-off-by: Namjae Jeon <[email protected]>
>> ---
>> misc/e4defrag.8.in | 10 ++++++++++
>> misc/e4defrag.c | 34 ++++++++++++++++++++++------------
>> 2 files changed, 32 insertions(+), 12 deletions(-)
>>
>> diff --git a/misc/e4defrag.8.in b/misc/e4defrag.8.in
>> index 75e1bc9..7090e51 100644
>> --- a/misc/e4defrag.8.in
>> +++ b/misc/e4defrag.8.in
>> @@ -9,6 +9,9 @@ e4defrag \- online defragmenter for ext4 filesystem
>> [
>> .B \-v
>> ]
>> +[
>> +.B \-m mtab
>> +]
>> .I target
>> \&...
>> .SH DESCRIPTION
>> @@ -57,6 +60,13 @@ is never defragmented.
>> .B \-v
>> Print error messages and the fragmentation count before and after defrag for
>> each file.
>> +.TP
>> +.B \-m mtab
>> +This option will specify the file to be scanned for obtaining mounted filesystems
>> +information. If this option is not specified, the default is to use
>> +.B /proc/mounts .
>> +If this file is not accessible, e4defrag will try to get required information from
>> +.B /etc/mtab
>> .SH NOTES
>> .B e4defrag
>> does not support swap file, files in lost+found directory, and files allocated
>> diff --git a/misc/e4defrag.c b/misc/e4defrag.c
>> index 4b31d03..3567e9f 100644
>> --- a/misc/e4defrag.c
>> +++ b/misc/e4defrag.c
>> @@ -123,6 +123,7 @@
>> #define NGMSG_FILE_OPEN "Failed to open"
>> #define NGMSG_FILE_UNREG "File is not regular file"
>> #define NGMSG_LOST_FOUND "Can not process \"lost+found\""
>> +#define _PATH_PROC_MOUNTS "/proc/mounts"
>>
>> /* Data type for filesystem-wide blocks number */
>> typedef unsigned long long ext4_fsblk_t;
>> @@ -262,10 +263,8 @@ static int fallocate64(int fd, int mode, loff_t offset, loff_t len)
>> * @dir_path_len: the length of directory.
>> */
>> static int get_mount_point(const char *devname, char *mount_point,
>> - int dir_path_len)
>> + int dir_path_len, const char *mtab)
>> {
>> - /* Refer to /etc/mtab */
>> - const char *mtab = MOUNTED;
>> FILE *fp = NULL;
>> struct mntent *mnt = NULL;
>> struct stat64 sb;
>> @@ -278,7 +277,7 @@ static int get_mount_point(const char *devname, char *mount_point,
>>
>> fp = setmntent(mtab, "r");
>> if (fp == NULL) {
>> - perror("Couldn't access /etc/mtab");
>> + printf("Couldn't access %s\n", mtab);
>> return -1;
>> }
>>
>> @@ -313,14 +312,12 @@ static int get_mount_point(const char *devname, char *mount_point,
>> *
>> * @file: the file's name.
>> */
>> -static int is_ext4(const char *file, char *devname)
>> +static int is_ext4(const char *file, char *devname, const char *mtab)
>> {
>> int maxlen = 0;
>> int len, ret;
>> FILE *fp = NULL;
>> char *mnt_type = NULL;
>> - /* Refer to /etc/mtab */
>> - const char *mtab = MOUNTED;
>> char file_path[PATH_MAX + 1];
>> struct mntent *mnt = NULL;
>> struct statfs64 fsbuf;
>> @@ -345,7 +342,7 @@ static int is_ext4(const char *file, char *devname)
>>
>> fp = setmntent(mtab, "r");
>> if (fp == NULL) {
>> - perror("Couldn't access /etc/mtab");
>> + printf("Couldn't access %s", mtab);
>> return -1;
>> }
>>
>> @@ -374,6 +371,10 @@ static int is_ext4(const char *file, char *devname)
>> }
>>
>> endmntent(fp);
>> + if (mnt_type == NULL) {
>> + printf("Could not get mount information from %s\n", mtab);
>> + return -1;
>> + }
>> if (strcmp(mnt_type, FS_EXT4) == 0) {
>> FREE(mnt_type);
>> return 0;
>> @@ -1724,6 +1725,7 @@ int main(int argc, char *argv[])
>> int success_flag = 0;
>> char dir_name[PATH_MAX + 1];
>> char dev_name[PATH_MAX + 1];
>> + char *mtab = NULL;
>> struct stat64 buf;
>> ext2_filsys fs = NULL;
>>
>> @@ -1731,7 +1733,7 @@ int main(int argc, char *argv[])
>> if (argc == 1)
>> goto out;
>>
>> - while ((opt = getopt(argc, argv, "vc")) != EOF) {
>> + while ((opt = getopt(argc, argv, "vcm:")) != EOF) {
>> switch (opt) {
>> case 'v':
>> mode_flag |= DETAIL;
>> @@ -1739,11 +1741,19 @@ int main(int argc, char *argv[])
>> case 'c':
>> mode_flag |= STATISTIC;
>> break;
>> + case 'm':
>> + mtab = optarg;
>> + break;
>> default:
>> goto out;
>> }
>> }
>> -
>> + if (!mtab) {
>> + if (access(_PATH_PROC_MOUNTS, R_OK) == 0)
>> + mtab = _PATH_PROC_MOUNTS;
>> + else
>> + mtab = _PATH_MOUNTED;
>> + }
>> if (argc == optind)
>> goto out;
>>
>> @@ -1797,7 +1807,7 @@ int main(int argc, char *argv[])
>> if (S_ISBLK(buf.st_mode)) {
>> /* Block device */
>> strncpy(dev_name, argv[i], strnlen(argv[i], PATH_MAX));
>> - if (get_mount_point(argv[i], dir_name, PATH_MAX) < 0)
>> + if (get_mount_point(argv[i], dir_name, PATH_MAX, mtab) < 0)
>> continue;
>> if (lstat64(dir_name, &buf) < 0) {
>> perror(NGMSG_FILE_INFO);
>> @@ -1833,7 +1843,7 @@ int main(int argc, char *argv[])
>> * filesystem type checked in get_mount_point()
>> */
>> if (arg_type == FILENAME || arg_type == DIRNAME) {
>> - if (is_ext4(argv[i], dev_name) < 0)
>> + if (is_ext4(argv[i], dev_name, mtab) < 0)
>> continue;
>> if (realpath(argv[i], dir_name) == NULL) {
>> perror("Couldn't get full path");
>>
>
On 10/17/12 9:57 PM, Ashish Sangwan wrote:
> On Wed, Oct 17, 2012 at 10:36 PM, Eric Sandeen <[email protected]> wrote:
>> On 10/17/12 11:52 AM, Ashish Sangwan wrote:
>>> Currently, e4defrag will not work on machines where /etc/mtab is not present
>>> OR is empty.
>>> This patch does 3 things:
>>> a) Add option "-m mtab" to e4defrag so that user can specify any file to
>>> be scanned for otbtaining mounted filesystems info.
>>
>> Under what conditions would this be useful; i.e. when is mtab information
>> ever in a file other than /etc/mtab?
>
> On embedded systems usually /etc is read-only. In that case /etc/mtab,
> though present, is empty.
> When we tried to run e4defrag on our system, it gave segfault due to
> the reasons mentioned in patch.
Clearly the segfault needs to be fixed, and looking at /proc/mounts makes sense.
But I just wonder about the usefulness of being able to specify an arbitrary
file in lieu of /etc/mtab. Unless there's a clear usecase I'm not sure I'd
add it.
> Then we look into xfs_fsr and found that it has this -m mtab option
> due to which it worked without any problem
> on our system. Also, xfs_fsr scans /proc/mounts first. So we changed
> e4defrag accordingly.
Compatibility with xfs_fsr is the only reason I can think of to do it :)
I just can't imagine why mount information would be anywhere other than
/etc/mtab or /proc/mounts.
Just pushing back on the complexity a little.
Thanks,
-Eric
>> Thanks,
>> -Eric
>>
>>> b) If mtab option is not specified, first we try to scan /proc/mounts, if failed
>>> to access this file, we try with /etc/mtab.
>>> c) In function is_ext4, check if the varibale "mnt_type" is null before
>>> calling strcmp, otherwise segfault would occur if mtab is empty.
>>>
>>> Signed-off-by: Ashish Sangwan <[email protected]>
>>> Signed-off-by: Namjae Jeon <[email protected]>
>>> ---
>>> misc/e4defrag.8.in | 10 ++++++++++
>>> misc/e4defrag.c | 34 ++++++++++++++++++++++------------
>>> 2 files changed, 32 insertions(+), 12 deletions(-)
>>>
>>> diff --git a/misc/e4defrag.8.in b/misc/e4defrag.8.in
>>> index 75e1bc9..7090e51 100644
>>> --- a/misc/e4defrag.8.in
>>> +++ b/misc/e4defrag.8.in
>>> @@ -9,6 +9,9 @@ e4defrag \- online defragmenter for ext4 filesystem
>>> [
>>> .B \-v
>>> ]
>>> +[
>>> +.B \-m mtab
>>> +]
>>> .I target
>>> \&...
>>> .SH DESCRIPTION
>>> @@ -57,6 +60,13 @@ is never defragmented.
>>> .B \-v
>>> Print error messages and the fragmentation count before and after defrag for
>>> each file.
>>> +.TP
>>> +.B \-m mtab
>>> +This option will specify the file to be scanned for obtaining mounted filesystems
>>> +information. If this option is not specified, the default is to use
>>> +.B /proc/mounts .
>>> +If this file is not accessible, e4defrag will try to get required information from
>>> +.B /etc/mtab
>>> .SH NOTES
>>> .B e4defrag
>>> does not support swap file, files in lost+found directory, and files allocated
>>> diff --git a/misc/e4defrag.c b/misc/e4defrag.c
>>> index 4b31d03..3567e9f 100644
>>> --- a/misc/e4defrag.c
>>> +++ b/misc/e4defrag.c
>>> @@ -123,6 +123,7 @@
>>> #define NGMSG_FILE_OPEN "Failed to open"
>>> #define NGMSG_FILE_UNREG "File is not regular file"
>>> #define NGMSG_LOST_FOUND "Can not process \"lost+found\""
>>> +#define _PATH_PROC_MOUNTS "/proc/mounts"
>>>
>>> /* Data type for filesystem-wide blocks number */
>>> typedef unsigned long long ext4_fsblk_t;
>>> @@ -262,10 +263,8 @@ static int fallocate64(int fd, int mode, loff_t offset, loff_t len)
>>> * @dir_path_len: the length of directory.
>>> */
>>> static int get_mount_point(const char *devname, char *mount_point,
>>> - int dir_path_len)
>>> + int dir_path_len, const char *mtab)
>>> {
>>> - /* Refer to /etc/mtab */
>>> - const char *mtab = MOUNTED;
>>> FILE *fp = NULL;
>>> struct mntent *mnt = NULL;
>>> struct stat64 sb;
>>> @@ -278,7 +277,7 @@ static int get_mount_point(const char *devname, char *mount_point,
>>>
>>> fp = setmntent(mtab, "r");
>>> if (fp == NULL) {
>>> - perror("Couldn't access /etc/mtab");
>>> + printf("Couldn't access %s\n", mtab);
>>> return -1;
>>> }
>>>
>>> @@ -313,14 +312,12 @@ static int get_mount_point(const char *devname, char *mount_point,
>>> *
>>> * @file: the file's name.
>>> */
>>> -static int is_ext4(const char *file, char *devname)
>>> +static int is_ext4(const char *file, char *devname, const char *mtab)
>>> {
>>> int maxlen = 0;
>>> int len, ret;
>>> FILE *fp = NULL;
>>> char *mnt_type = NULL;
>>> - /* Refer to /etc/mtab */
>>> - const char *mtab = MOUNTED;
>>> char file_path[PATH_MAX + 1];
>>> struct mntent *mnt = NULL;
>>> struct statfs64 fsbuf;
>>> @@ -345,7 +342,7 @@ static int is_ext4(const char *file, char *devname)
>>>
>>> fp = setmntent(mtab, "r");
>>> if (fp == NULL) {
>>> - perror("Couldn't access /etc/mtab");
>>> + printf("Couldn't access %s", mtab);
>>> return -1;
>>> }
>>>
>>> @@ -374,6 +371,10 @@ static int is_ext4(const char *file, char *devname)
>>> }
>>>
>>> endmntent(fp);
>>> + if (mnt_type == NULL) {
>>> + printf("Could not get mount information from %s\n", mtab);
>>> + return -1;
>>> + }
>>> if (strcmp(mnt_type, FS_EXT4) == 0) {
>>> FREE(mnt_type);
>>> return 0;
>>> @@ -1724,6 +1725,7 @@ int main(int argc, char *argv[])
>>> int success_flag = 0;
>>> char dir_name[PATH_MAX + 1];
>>> char dev_name[PATH_MAX + 1];
>>> + char *mtab = NULL;
>>> struct stat64 buf;
>>> ext2_filsys fs = NULL;
>>>
>>> @@ -1731,7 +1733,7 @@ int main(int argc, char *argv[])
>>> if (argc == 1)
>>> goto out;
>>>
>>> - while ((opt = getopt(argc, argv, "vc")) != EOF) {
>>> + while ((opt = getopt(argc, argv, "vcm:")) != EOF) {
>>> switch (opt) {
>>> case 'v':
>>> mode_flag |= DETAIL;
>>> @@ -1739,11 +1741,19 @@ int main(int argc, char *argv[])
>>> case 'c':
>>> mode_flag |= STATISTIC;
>>> break;
>>> + case 'm':
>>> + mtab = optarg;
>>> + break;
>>> default:
>>> goto out;
>>> }
>>> }
>>> -
>>> + if (!mtab) {
>>> + if (access(_PATH_PROC_MOUNTS, R_OK) == 0)
>>> + mtab = _PATH_PROC_MOUNTS;
>>> + else
>>> + mtab = _PATH_MOUNTED;
>>> + }
>>> if (argc == optind)
>>> goto out;
>>>
>>> @@ -1797,7 +1807,7 @@ int main(int argc, char *argv[])
>>> if (S_ISBLK(buf.st_mode)) {
>>> /* Block device */
>>> strncpy(dev_name, argv[i], strnlen(argv[i], PATH_MAX));
>>> - if (get_mount_point(argv[i], dir_name, PATH_MAX) < 0)
>>> + if (get_mount_point(argv[i], dir_name, PATH_MAX, mtab) < 0)
>>> continue;
>>> if (lstat64(dir_name, &buf) < 0) {
>>> perror(NGMSG_FILE_INFO);
>>> @@ -1833,7 +1843,7 @@ int main(int argc, char *argv[])
>>> * filesystem type checked in get_mount_point()
>>> */
>>> if (arg_type == FILENAME || arg_type == DIRNAME) {
>>> - if (is_ext4(argv[i], dev_name) < 0)
>>> + if (is_ext4(argv[i], dev_name, mtab) < 0)
>>> continue;
>>> if (realpath(argv[i], dir_name) == NULL) {
>>> perror("Couldn't get full path");
>>>
>>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
On Thu, Oct 18, 2012 at 8:30 AM, Eric Sandeen <[email protected]> wrote:
> On 10/17/12 9:57 PM, Ashish Sangwan wrote:
>> On Wed, Oct 17, 2012 at 10:36 PM, Eric Sandeen <[email protected]> wrote:
>>> On 10/17/12 11:52 AM, Ashish Sangwan wrote:
>>>> Currently, e4defrag will not work on machines where /etc/mtab is not present
>>>> OR is empty.
>>>> This patch does 3 things:
>>>> a) Add option "-m mtab" to e4defrag so that user can specify any file to
>>>> be scanned for otbtaining mounted filesystems info.
>>>
>>> Under what conditions would this be useful; i.e. when is mtab information
>>> ever in a file other than /etc/mtab?
>>
>> On embedded systems usually /etc is read-only. In that case /etc/mtab,
>> though present, is empty.
>> When we tried to run e4defrag on our system, it gave segfault due to
>> the reasons mentioned in patch.
>
> Clearly the segfault needs to be fixed, and looking at /proc/mounts makes sense.
> But I just wonder about the usefulness of being able to specify an arbitrary
> file in lieu of /etc/mtab. Unless there's a clear usecase I'm not sure I'd
> add it.
>
>> Then we look into xfs_fsr and found that it has this -m mtab option
>> due to which it worked without any problem
>> on our system. Also, xfs_fsr scans /proc/mounts first. So we changed
>> e4defrag accordingly.
>
> Compatibility with xfs_fsr is the only reason I can think of to do it :)
>
> I just can't imagine why mount information would be anywhere other than
> /etc/mtab or /proc/mounts.
>
you are right. Actually xfs_fsr may work on more than 1 mounted XFS
filesystem in a single run.
That is why it makes _little_ sense for xfs_fsr to have this mtab
option so that user can provide
exclusive mounted xfs partitions info in a seprate file.
But e4defrag would work on a single mounted partition in a single run.
This won't be much helpful here if not for compatiblity.
> Just pushing back on the complexity a little.
>
> Thanks,
> -Eric
>
>>> Thanks,
>>> -Eric
>>>
>>>> b) If mtab option is not specified, first we try to scan /proc/mounts, if failed
>>>> to access this file, we try with /etc/mtab.
>>>> c) In function is_ext4, check if the varibale "mnt_type" is null before
>>>> calling strcmp, otherwise segfault would occur if mtab is empty.
>>>>
>>>> Signed-off-by: Ashish Sangwan <[email protected]>
>>>> Signed-off-by: Namjae Jeon <[email protected]>
>>>> ---
>>>> misc/e4defrag.8.in | 10 ++++++++++
>>>> misc/e4defrag.c | 34 ++++++++++++++++++++++------------
>>>> 2 files changed, 32 insertions(+), 12 deletions(-)
>>>>
>>>> diff --git a/misc/e4defrag.8.in b/misc/e4defrag.8.in
>>>> index 75e1bc9..7090e51 100644
>>>> --- a/misc/e4defrag.8.in
>>>> +++ b/misc/e4defrag.8.in
>>>> @@ -9,6 +9,9 @@ e4defrag \- online defragmenter for ext4 filesystem
>>>> [
>>>> .B \-v
>>>> ]
>>>> +[
>>>> +.B \-m mtab
>>>> +]
>>>> .I target
>>>> \&...
>>>> .SH DESCRIPTION
>>>> @@ -57,6 +60,13 @@ is never defragmented.
>>>> .B \-v
>>>> Print error messages and the fragmentation count before and after defrag for
>>>> each file.
>>>> +.TP
>>>> +.B \-m mtab
>>>> +This option will specify the file to be scanned for obtaining mounted filesystems
>>>> +information. If this option is not specified, the default is to use
>>>> +.B /proc/mounts .
>>>> +If this file is not accessible, e4defrag will try to get required information from
>>>> +.B /etc/mtab
>>>> .SH NOTES
>>>> .B e4defrag
>>>> does not support swap file, files in lost+found directory, and files allocated
>>>> diff --git a/misc/e4defrag.c b/misc/e4defrag.c
>>>> index 4b31d03..3567e9f 100644
>>>> --- a/misc/e4defrag.c
>>>> +++ b/misc/e4defrag.c
>>>> @@ -123,6 +123,7 @@
>>>> #define NGMSG_FILE_OPEN "Failed to open"
>>>> #define NGMSG_FILE_UNREG "File is not regular file"
>>>> #define NGMSG_LOST_FOUND "Can not process \"lost+found\""
>>>> +#define _PATH_PROC_MOUNTS "/proc/mounts"
>>>>
>>>> /* Data type for filesystem-wide blocks number */
>>>> typedef unsigned long long ext4_fsblk_t;
>>>> @@ -262,10 +263,8 @@ static int fallocate64(int fd, int mode, loff_t offset, loff_t len)
>>>> * @dir_path_len: the length of directory.
>>>> */
>>>> static int get_mount_point(const char *devname, char *mount_point,
>>>> - int dir_path_len)
>>>> + int dir_path_len, const char *mtab)
>>>> {
>>>> - /* Refer to /etc/mtab */
>>>> - const char *mtab = MOUNTED;
>>>> FILE *fp = NULL;
>>>> struct mntent *mnt = NULL;
>>>> struct stat64 sb;
>>>> @@ -278,7 +277,7 @@ static int get_mount_point(const char *devname, char *mount_point,
>>>>
>>>> fp = setmntent(mtab, "r");
>>>> if (fp == NULL) {
>>>> - perror("Couldn't access /etc/mtab");
>>>> + printf("Couldn't access %s\n", mtab);
>>>> return -1;
>>>> }
>>>>
>>>> @@ -313,14 +312,12 @@ static int get_mount_point(const char *devname, char *mount_point,
>>>> *
>>>> * @file: the file's name.
>>>> */
>>>> -static int is_ext4(const char *file, char *devname)
>>>> +static int is_ext4(const char *file, char *devname, const char *mtab)
>>>> {
>>>> int maxlen = 0;
>>>> int len, ret;
>>>> FILE *fp = NULL;
>>>> char *mnt_type = NULL;
>>>> - /* Refer to /etc/mtab */
>>>> - const char *mtab = MOUNTED;
>>>> char file_path[PATH_MAX + 1];
>>>> struct mntent *mnt = NULL;
>>>> struct statfs64 fsbuf;
>>>> @@ -345,7 +342,7 @@ static int is_ext4(const char *file, char *devname)
>>>>
>>>> fp = setmntent(mtab, "r");
>>>> if (fp == NULL) {
>>>> - perror("Couldn't access /etc/mtab");
>>>> + printf("Couldn't access %s", mtab);
>>>> return -1;
>>>> }
>>>>
>>>> @@ -374,6 +371,10 @@ static int is_ext4(const char *file, char *devname)
>>>> }
>>>>
>>>> endmntent(fp);
>>>> + if (mnt_type == NULL) {
>>>> + printf("Could not get mount information from %s\n", mtab);
>>>> + return -1;
>>>> + }
>>>> if (strcmp(mnt_type, FS_EXT4) == 0) {
>>>> FREE(mnt_type);
>>>> return 0;
>>>> @@ -1724,6 +1725,7 @@ int main(int argc, char *argv[])
>>>> int success_flag = 0;
>>>> char dir_name[PATH_MAX + 1];
>>>> char dev_name[PATH_MAX + 1];
>>>> + char *mtab = NULL;
>>>> struct stat64 buf;
>>>> ext2_filsys fs = NULL;
>>>>
>>>> @@ -1731,7 +1733,7 @@ int main(int argc, char *argv[])
>>>> if (argc == 1)
>>>> goto out;
>>>>
>>>> - while ((opt = getopt(argc, argv, "vc")) != EOF) {
>>>> + while ((opt = getopt(argc, argv, "vcm:")) != EOF) {
>>>> switch (opt) {
>>>> case 'v':
>>>> mode_flag |= DETAIL;
>>>> @@ -1739,11 +1741,19 @@ int main(int argc, char *argv[])
>>>> case 'c':
>>>> mode_flag |= STATISTIC;
>>>> break;
>>>> + case 'm':
>>>> + mtab = optarg;
>>>> + break;
>>>> default:
>>>> goto out;
>>>> }
>>>> }
>>>> -
>>>> + if (!mtab) {
>>>> + if (access(_PATH_PROC_MOUNTS, R_OK) == 0)
>>>> + mtab = _PATH_PROC_MOUNTS;
>>>> + else
>>>> + mtab = _PATH_MOUNTED;
>>>> + }
>>>> if (argc == optind)
>>>> goto out;
>>>>
>>>> @@ -1797,7 +1807,7 @@ int main(int argc, char *argv[])
>>>> if (S_ISBLK(buf.st_mode)) {
>>>> /* Block device */
>>>> strncpy(dev_name, argv[i], strnlen(argv[i], PATH_MAX));
>>>> - if (get_mount_point(argv[i], dir_name, PATH_MAX) < 0)
>>>> + if (get_mount_point(argv[i], dir_name, PATH_MAX, mtab) < 0)
>>>> continue;
>>>> if (lstat64(dir_name, &buf) < 0) {
>>>> perror(NGMSG_FILE_INFO);
>>>> @@ -1833,7 +1843,7 @@ int main(int argc, char *argv[])
>>>> * filesystem type checked in get_mount_point()
>>>> */
>>>> if (arg_type == FILENAME || arg_type == DIRNAME) {
>>>> - if (is_ext4(argv[i], dev_name) < 0)
>>>> + if (is_ext4(argv[i], dev_name, mtab) < 0)
>>>> continue;
>>>> if (realpath(argv[i], dir_name) == NULL) {
>>>> perror("Couldn't get full path");
>>>>
>>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
>> the body of a message to [email protected]
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>
>