Btrfs devel - Sep 2010 - [PATCH] Btrfs-progs: add btrfs filesystem disk-info command

This command just implements the BTRFS_IOC_DISK_INFO ioctl.  It gets all the
devices for a filesystem, reads /proc/partitions for the right dev info and
spits out pretty names.

Signed-off-by: Josef Bacik <josef@redhat.com>
---
 btrfs.c      |    4 ++
 btrfs_cmds.c |  101 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 btrfs_cmds.h |    1 +
 ioctl.h      |    8 ++++
 4 files changed, 114 insertions(+), 0 deletions(-)

diff --git a/btrfs.c b/btrfs.c
index ab5e57f..22b241b 100644
--- a/btrfs.c
+++ b/btrfs.c
@@ -91,6 +91,10 @@ static struct Command commands[] = {
 	  "filesystem df", "<path>\n"
 		"Show space usage information for a mount point\n."
 	},
+	{ do_disk_info, 1,
+	  "filesystem disk-info", "<path>\n"
+		"Show disks contained within this filesysten."
+	},
 	{ do_balance, 1,
 	  "filesystem balance", "<path>\n"
 		"Balance the chunks across the device."
diff --git a/btrfs_cmds.c b/btrfs_cmds.c
index 683aec0..b1a4d8d 100644
--- a/btrfs_cmds.c
+++ b/btrfs_cmds.c
@@ -835,6 +835,107 @@ int do_set_default_subvol(int nargs, char **argv)
 	return 0;
 }
 
+int do_disk_info(int nargs, char **argv)
+{
+	struct btrfs_ioctl_disk_info_args *args;
+	char *path = argv[1];
+	int devs;
+	int fd;
+	int ret;
+	int i;
+
+	fd = open_file_or_dir(path);
+	if (fd < 0) {
+		fprintf(stderr, "Error: can''t access
''%s''\n", path);
+		return 12;
+	}
+
+	args = malloc(sizeof(*args));
+	if (!args)
+		return -ENOMEM;
+
+	args->num_devices = 0;
+
+	ret = ioctl(fd, BTRFS_IOC_DISK_INFO, args);
+	if (ret) {
+		printf("failed ioctl\n");
+		free(args);
+		return ret;
+	}
+
+	if (!args->num_devices) {
+		printf("no devs\n");
+		free(args);
+		return 0;
+	}
+
+	devs = args->num_devices;
+	args = realloc(args, sizeof(*args) + (devs * sizeof(dev_t)));
+	if (!args) {
+		printf("enomem\n");
+		return -ENOMEM;
+	}
+	args->num_devices = devs;
+
+	ret = ioctl(fd, BTRFS_IOC_DISK_INFO, args);
+	if (ret) {
+		printf("ioctl failed second time\n");
+		free(args);
+		return -ENOMEM;
+	}
+	close(fd);
+
+	fd = open_file_or_dir("/proc/partitions");
+	if (fd < 0) {
+print:
+		printf("Devices in %s\n", path);
+		for (i = 0; i < args->num_devices; i++)
+			printf("\t%d:%d\n", major(args->devices[i]),
+			       minor(args->devices[i]));
+		close(fd);
+	} else {
+		int major, minor;
+		unsigned long long blocks;
+		char buf[128];
+		char name[32];
+		FILE *f;
+		int found_devices = 0;
+
+		f = fdopen(fd, "r");
+		if (!f)
+			goto print;
+
+		printf("Devices in %s\n", path);
+		while (!feof(f)) {
+			char *blah;
+
+			memset(name, 0, 32);
+			memset(buf, 0, 128);
+
+			blah = fgets(buf, 128, f);
+
+			ret = sscanf(buf, "%d %d %llu %32s", &major, &minor,
&blocks, name);
+			if (!ret)
+				continue;
+
+			for (i = 0; i < args->num_devices; i++) {
+				if (major(args->devices[i]) != major)
+					continue;
+				if (minor(args->devices[i]) != minor)
+					continue;
+				found_devices++;
+				printf("\t/dev/%s\n", name);
+				break;
+			}
+			if (found_devices == args->num_devices)
+				break;
+		}
+		fclose(f);
+	}
+	free(args);
+	return 0;
+}
+
 int do_df_filesystem(int nargs, char **argv)
 {
 	struct btrfs_ioctl_space_args *sargs;
diff --git a/btrfs_cmds.h b/btrfs_cmds.h
index 7bde191..0b5038a 100644
--- a/btrfs_cmds.h
+++ b/btrfs_cmds.h
@@ -31,4 +31,5 @@ int do_set_default_subvol(int nargs, char **argv);
 int list_subvols(int fd);
 int do_df_filesystem(int nargs, char **argv);
 int find_updated_files(int fd, u64 root_id, u64 oldest_gen);
+int do_disk_info(int nargs, char **argv);
 int do_find_newer(int argc, char **argv);
diff --git a/ioctl.h b/ioctl.h
index 776d7a9..4ace64f 100644
--- a/ioctl.h
+++ b/ioctl.h
@@ -19,6 +19,7 @@
 #ifndef __IOCTL_
 #define __IOCTL_
 #include <asm/types.h>
+#include <sys/types.h>
 #include <linux/ioctl.h>
 
 #define BTRFS_IOCTL_MAGIC 0x94
@@ -132,6 +133,11 @@ struct btrfs_ioctl_space_args {
 	struct btrfs_ioctl_space_info spaces[0];
 };
 
+struct btrfs_ioctl_disk_info_args {
+	__u32 num_devices;
+	__u64 devices[0];
+};
+
 #define BTRFS_IOC_SNAP_CREATE _IOW(BTRFS_IOCTL_MAGIC, 1, \
 				   struct btrfs_ioctl_vol_args)
 #define BTRFS_IOC_DEFRAG _IOW(BTRFS_IOCTL_MAGIC, 2, \
@@ -169,4 +175,6 @@ struct btrfs_ioctl_space_args {
 #define BTRFS_IOC_DEFAULT_SUBVOL _IOW(BTRFS_IOCTL_MAGIC, 19, u64)
 #define BTRFS_IOC_SPACE_INFO _IOWR(BTRFS_IOCTL_MAGIC, 20, \
 				    struct btrfs_ioctl_space_args)
+#define BTRFS_IOC_DISK_INFO _IOWR(BTRFS_IOCTL_MAGIC, 21, \
+				  struct btrfs_ioctl_disk_info_args)
 #endif
-- 
1.6.6.1

--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs"
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Hi Josef,

please, if you add or change a command pay attention to update the man page 
too (man/btrfs.8.in).

See my comments below

On Tuesday, 28 September, 2010, Josef Bacik wrote:
> This command just implements the BTRFS_IOC_DISK_INFO ioctl.  It gets all
the
> devices for a filesystem, reads /proc/partitions for the right dev info and
> spits out pretty names.
> 
> Signed-off-by: Josef Bacik <josef@redhat.com>
> ---
>  btrfs.c      |    4 ++
>  btrfs_cmds.c |  101 
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  btrfs_cmds.h |    1 +
>  ioctl.h      |    8 ++++
>  4 files changed, 114 insertions(+), 0 deletions(-)
> 
> diff --git a/btrfs.c b/btrfs.c
> index ab5e57f..22b241b 100644
> --- a/btrfs.c
> +++ b/btrfs.c
> @@ -91,6 +91,10 @@ static struct Command commands[] = {
>  	  "filesystem df", "<path>\n"
>  		"Show space usage information for a mount point\n."
>  	},
> +	{ do_disk_info, 1,
> +	  "filesystem disk-info", "<path>\n"
> +		"Show disks contained within this filesysten."
> +	},
>  	{ do_balance, 1,
>  	  "filesystem balance", "<path>\n"
>  		"Balance the chunks across the device."
> diff --git a/btrfs_cmds.c b/btrfs_cmds.c
> index 683aec0..b1a4d8d 100644
> --- a/btrfs_cmds.c
> +++ b/btrfs_cmds.c
> @@ -835,6 +835,107 @@ int do_set_default_subvol(int nargs, char **argv)
>  	return 0;
>  }
>  
> +int do_disk_info(int nargs, char **argv)
> +{
> +	struct btrfs_ioctl_disk_info_args *args;
> +	char *path = argv[1];
> +	int devs;
> +	int fd;
> +	int ret;
> +	int i;
> +
> +	fd = open_file_or_dir(path);
> +	if (fd < 0) {
> +		fprintf(stderr, "Error: can''t access
''%s''\n", path);
> +		return 12;
> +	}
> +
> +	args = malloc(sizeof(*args));
> +	if (!args)
> +		return -ENOMEM;
> +
> +	args->num_devices = 0;
> +
> +	ret = ioctl(fd, BTRFS_IOC_DISK_INFO, args);
> +	if (ret) {
> +		printf("failed ioctl\n");
Please use
		fprintf(stderr,"ERROR: failed ioctl\n");
> +		free(args);
> +		return ret;
> +	}
> +
> +	if (!args->num_devices) {
> +		printf("no devs\n");
> +		free(args);
> +		return 0;
> +	}
> +
> +	devs = args->num_devices;
> +	args = realloc(args, sizeof(*args) + (devs * sizeof(dev_t)));
> +	if (!args) {
> +		printf("enomem\n");
Please use
		fprintf(stderr,"ERROR: not enough
memory\n");
> +		return -ENOMEM;
> +	}
> +	args->num_devices = devs;
> +
> +	ret = ioctl(fd, BTRFS_IOC_DISK_INFO, args);
> +	if (ret) {
> +		printf("ioctl failed second time\n");
Please use
		fprintf(stderr,"ERROR: ioctl failed (second time)\n");
> +		free(args);
> +		return -ENOMEM;
> +	}
> +	close(fd);
> +
> +	fd = open_file_or_dir("/proc/partitions");
Why not

	f = fopen("/proc/partitions","r")

So you can avoid "f = fdopen(fd,"r")" and the "goto
print"
> +	if (fd < 0) {
> +print:
> +		printf("Devices in %s\n", path);
> +		for (i = 0; i < args->num_devices; i++)
> +			printf("\t%d:%d\n", major(args->devices[i]),
> +			       minor(args->devices[i]));
> +		close(fd);
		^^^^^^^^^
why close fd ? ... ok, in case of fdopen(fd,"r") == 0
> +	} else {
> +		int major, minor;
> +		unsigned long long blocks;
> +		char buf[128];
> +		char name[32];
> +		FILE *f;
> +		int found_devices = 0;
> +
> +		f = fdopen(fd, "r");
> +		if (!f)
> +			goto print;
See my comments above 
> +
> +		printf("Devices in %s\n", path);
> +		while (!feof(f)) {
> +			char *blah;
> +
> +			memset(name, 0, 32);
> +			memset(buf, 0, 128);
> +
> +			blah = fgets(buf, 128, f);
> +
> +			ret = sscanf(buf, "%d %d %llu %32s", &major, &minor, 
&blocks, name);
> +			if (!ret)
> +				continue;
> +
> +			for (i = 0; i < args->num_devices; i++) {
> +				if (major(args->devices[i]) != major)
> +					continue;
> +				if (minor(args->devices[i]) != minor)
> +					continue;
> +				found_devices++;
> +				printf("\t/dev/%s\n", name);
> +				break;
> +			}
> +			if (found_devices == args->num_devices)
> +				break;
> +		}
> +		fclose(f);
> +	}
> +	free(args);
> +	return 0;
> +}
> +
>  int do_df_filesystem(int nargs, char **argv)
>  {
>  	struct btrfs_ioctl_space_args *sargs;
> diff --git a/btrfs_cmds.h b/btrfs_cmds.h
> index 7bde191..0b5038a 100644
> --- a/btrfs_cmds.h
> +++ b/btrfs_cmds.h
> @@ -31,4 +31,5 @@ int do_set_default_subvol(int nargs, char **argv);
>  int list_subvols(int fd);
>  int do_df_filesystem(int nargs, char **argv);
>  int find_updated_files(int fd, u64 root_id, u64 oldest_gen);
> +int do_disk_info(int nargs, char **argv);
>  int do_find_newer(int argc, char **argv);
> diff --git a/ioctl.h b/ioctl.h
> index 776d7a9..4ace64f 100644
> --- a/ioctl.h
> +++ b/ioctl.h
> @@ -19,6 +19,7 @@
>  #ifndef __IOCTL_
>  #define __IOCTL_
>  #include <asm/types.h>
> +#include <sys/types.h>
>  #include <linux/ioctl.h>
>  
>  #define BTRFS_IOCTL_MAGIC 0x94
> @@ -132,6 +133,11 @@ struct btrfs_ioctl_space_args {
>  	struct btrfs_ioctl_space_info spaces[0];
>  };
>  
> +struct btrfs_ioctl_disk_info_args {
> +	__u32 num_devices;
> +	__u64 devices[0];
> +};
> +
>  #define BTRFS_IOC_SNAP_CREATE _IOW(BTRFS_IOCTL_MAGIC, 1, \
>  				   struct btrfs_ioctl_vol_args)
>  #define BTRFS_IOC_DEFRAG _IOW(BTRFS_IOCTL_MAGIC, 2, \
> @@ -169,4 +175,6 @@ struct btrfs_ioctl_space_args {
>  #define BTRFS_IOC_DEFAULT_SUBVOL _IOW(BTRFS_IOCTL_MAGIC, 19, u64)
>  #define BTRFS_IOC_SPACE_INFO _IOWR(BTRFS_IOCTL_MAGIC, 20, \
>  				    struct btrfs_ioctl_space_args)
> +#define BTRFS_IOC_DISK_INFO _IOWR(BTRFS_IOCTL_MAGIC, 21, \
> +				  struct btrfs_ioctl_disk_info_args)
>  #endif
> -- 
> 1.6.6.1
> 
> --
> To unsubscribe from this list: send the line "unsubscribe
linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

-- 
gpg key@ keyserver.linux.it: Goffredo Baroncelli (ghigo)
<kreijack@inwind.it>
Key fingerprint = 4769 7E51 5293 D36C 814E  C054 BF04 F161 3DC5 0512
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs"
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

On Wed, Sep 29, 2010 at 12:48:15AM +0200, Goffredo Baroncelli
wrote:
> Hi Josef,
> 
> please, if you add or change a command pay attention to update the man page
> too (man/btrfs.8.in).
>
Hrm I missed that with git add, I''ll fix that up.
 
> See my comments below
> 
> On Tuesday, 28 September, 2010, Josef Bacik wrote:
> > This command just implements the BTRFS_IOC_DISK_INFO ioctl.  It gets
all the
> > devices for a filesystem, reads /proc/partitions for the right dev
info and
> > spits out pretty names.
> > 
> > Signed-off-by: Josef Bacik <josef@redhat.com>
> > ---
> >  btrfs.c      |    4 ++
> >  btrfs_cmds.c |  101 
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  btrfs_cmds.h |    1 +
> >  ioctl.h      |    8 ++++
> >  4 files changed, 114 insertions(+), 0 deletions(-)
> > 
> > diff --git a/btrfs.c b/btrfs.c
> > index ab5e57f..22b241b 100644
> > --- a/btrfs.c
> > +++ b/btrfs.c
> > @@ -91,6 +91,10 @@ static struct Command commands[] = {
> >  	  "filesystem df", "<path>\n"
> >  		"Show space usage information for a mount point\n."
> >  	},
> > +	{ do_disk_info, 1,
> > +	  "filesystem disk-info", "<path>\n"
> > +		"Show disks contained within this filesysten."
> > +	},
> >  	{ do_balance, 1,
> >  	  "filesystem balance", "<path>\n"
> >  		"Balance the chunks across the device."
> > diff --git a/btrfs_cmds.c b/btrfs_cmds.c
> > index 683aec0..b1a4d8d 100644
> > --- a/btrfs_cmds.c
> > +++ b/btrfs_cmds.c
> > @@ -835,6 +835,107 @@ int do_set_default_subvol(int nargs, char
**argv)
> >  	return 0;
> >  }
> >  
> > +int do_disk_info(int nargs, char **argv)
> > +{
> > +	struct btrfs_ioctl_disk_info_args *args;
> > +	char *path = argv[1];
> > +	int devs;
> > +	int fd;
> > +	int ret;
> > +	int i;
> > +
> > +	fd = open_file_or_dir(path);
> > +	if (fd < 0) {
> > +		fprintf(stderr, "Error: can''t access
''%s''\n", path);
> > +		return 12;
> > +	}
> > +
> > +	args = malloc(sizeof(*args));
> > +	if (!args)
> > +		return -ENOMEM;
> > +
> > +	args->num_devices = 0;
> > +
> > +	ret = ioctl(fd, BTRFS_IOC_DISK_INFO, args);
> > +	if (ret) {
> > +		printf("failed ioctl\n");
> Please use
> 		fprintf(stderr,"ERROR: failed ioctl\n");
>
Ugh oops sorry, forgot to get rid of my debug printing, I''ll kill that.
 
> > +		free(args);
> > +		return ret;
> > +	}
> > +
> > +	if (!args->num_devices) {
> > +		printf("no devs\n");
> > +		free(args);
> > +		return 0;
> > +	}
> > +
> > +	devs = args->num_devices;
> > +	args = realloc(args, sizeof(*args) + (devs * sizeof(dev_t)));
> > +	if (!args) {
> > +		printf("enomem\n");
> Please use
> 		fprintf(stderr,"ERROR: not enough memory\n");
Yeah another debug print.
> > +		return -ENOMEM;
> > +	}
> > +	args->num_devices = devs;
> > +
> > +	ret = ioctl(fd, BTRFS_IOC_DISK_INFO, args);
> > +	if (ret) {
> > +		printf("ioctl failed second time\n");
> Please use
> 		fprintf(stderr,"ERROR: ioctl failed (second time)\n");
> 
> > +		free(args);
> > +		return -ENOMEM;
> > +	}
> > +	close(fd);
> > +
> > +	fd = open_file_or_dir("/proc/partitions");
> 
> Why not
> 
> 	f = fopen("/proc/partitions","r")
> 
> So you can avoid "f = fdopen(fd,"r")" and the
"goto print"
> 
> > +	if (fd < 0) {
> > +print:
> > +		printf("Devices in %s\n", path);
> > +		for (i = 0; i < args->num_devices; i++)
> > +			printf("\t%d:%d\n", major(args->devices[i]),
> > +			       minor(args->devices[i]));
> > +		close(fd);
> 		^^^^^^^^^
> why close fd ? ... ok, in case of fdopen(fd,"r") == 0
>
Yeah I didn''t think this through well, I''ll fix it up.  I
mostly just sent this
as an afterthought.  When we figure out how the interface is going to look
I''ll
fix everything up and re-send.  Thanks,

Josef 
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs"
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

On Wednesday, 29 September, 2010, Josef Bacik wrote:
> On Wed, Sep 29, 2010 at 12:48:15AM +0200, Goffredo Baroncelli wrote:
> > Hi Josef,
> > 
> > please, if you add or change a command pay attention to update the man
page 
> > too (man/btrfs.8.in).
> >
> 
> Hrm I missed that with git add, I''ll fix that up.
[...]
> > > +
> > > +	ret = ioctl(fd, BTRFS_IOC_DISK_INFO, args);
> > > +	if (ret) {
> > > +		printf("failed ioctl\n");
> > Please use
> > 		fprintf(stderr,"ERROR: failed ioctl\n");
> >
> 
> Ugh oops sorry, forgot to get rid of my debug printing, I''ll kill
that.
If you use this command on a non btrfs filesystem, this is the first point of 
failure. So please don''t kill it.




-- 
gpg key@ keyserver.linux.it: Goffredo Baroncelli (ghigo)
<kreijack@inwind.it>
Key fingerprint = 4769 7E51 5293 D36C 814E  C054 BF04 F161 3DC5 0512
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs"
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html