btrfs: add -k option to filesystem df

Commit Message

Alexandre Oliva Aug. 30, 2014, 6:27 p.m. UTC

Introduce support for df to print sizes in KiB, easy to extend to other
bases.

The man page is also updated and fixed in that it made it seem like
multiple paths were accepted.

Signed-off-by: Alexandre Oliva <[e-mail]>
---
 Documentation/btrfs-filesystem.txt |    4 +++-
 cmds-filesystem.c                  |   26 +++++++++++++++++++++++---
 utils.c                            |   29 +++++++++++++++++++++++++++--
 utils.h                            |    1 +
 4 files changed, 54 insertions(+), 6 deletions(-)

Comments

Shriramana Sharma Aug. 31, 2014, 2:17 a.m. UTC | #1

On 8/30/14, Alexandre Oliva <[e-mail]> wrote:
> Introduce support for df to print sizes in KiB, easy to extend to other
> bases.

Hello. I'm glad to see this as I have been a fan of the binary units
for long (since they were introduced)!

However I feel the chosen long option could be improved as it reads
"kbytes" and:

1) currently SI units are being displayed as "kbytes" exist there too

2) it sounds as if it is intended to force display in kbytes only
whereas that is not the case.

What is actually being introduced is IEC units for the sizes. So --iec
and -i would be better choices for the options. Since btrfs fi df
currently doesn't seem to have any options (I am only looking at the
3.12 version on my system) this should not conflict with anything
else.

BTW this site: http://ram.kossboss.com/btrfs-fi-df-balance-btrfs-df/
seems to already show IEC units -- perhaps is it Alexandre's site?!

Alexandre Oliva Aug. 31, 2014, 6:07 p.m. UTC | #2

On Aug 30, 2014, Shriramana Sharma <[e-mail]> wrote:

> But somehow I feel the name of the long option could be made better than
> --kbytes which is not exactly descriptive of what it accomplishes. IIUC so
> far only bytes are displayed right?

kbytes displays KiBs, whereas the preexisting code chooses a magnitude
most suitable to present the size in a human-friendly way.  I'd be happy
to drop the long option, to follow GNU df's practice: there's no long
option (without arguments) equivalent to -k there.

Patch

diff --git a/Documentation/btrfs-filesystem.txt b/Documentation/btrfs-filesystem.txt
index c9c0b00..70ba4b8 100644
--- a/Documentation/btrfs-filesystem.txt
+++ b/Documentation/btrfs-filesystem.txt
@@ -17,8 +17,10 @@  resizing, defragment.
 
 SUBCOMMAND
 ----------
-*df* <path> [<path>...]::
+*df* [--kbytes] <path>::
 Show space usage information for a mount point.
++
+If '-k' or '--kbytes' is passed, sizes will be printed in KiB.
 
 *show* [--mounted|--all-devices|<path>|<uuid>|<device>|<label>]::
 Show the btrfs filesystem with some additional info.
diff --git a/cmds-filesystem.c b/cmds-filesystem.c
index 7e8ca95..737fcf3 100644
--- a/cmds-filesystem.c
+++ b/cmds-filesystem.c
@@ -113,8 +113,9 @@  static const char * const filesystem_cmd_group_usage[] = {
 };
 
 static const char * const cmd_df_usage[] = {
-	"btrfs filesystem df <path>",
+	"btrfs filesystem df [-k] <path>",
 	"Show space usage information for a mount point",
+	"-k|--kbytes        show disk spaces in KB",
 	NULL
 };
 
@@ -226,10 +227,29 @@  static int cmd_df(int argc, char **argv)
 	char *path;
 	DIR  *dirstream = NULL;
 
-	if (check_argc_exact(argc, 2))
+	while (1) {
+		int long_index;
+		static struct option long_options[] = {
+			{ "kbytes", no_argument, NULL, 'k'},
+			{ NULL, no_argument, NULL, 0 },
+		};
+		int c = getopt_long(argc, argv, "k", long_options,
+					&long_index);
+		if (c < 0)
+			break;
+		switch (c) {
+		case 'k':
+			pretty_size_force_base (1024);
+			break;
+		default:
+			usage(cmd_df_usage);
+		}
+	}
+
+	if (check_argc_max(argc, optind + 1))
 		usage(cmd_df_usage);
 
-	path = argv[1];
+	path = argv[optind];
 
 	fd = open_file_or_dir(path, &dirstream);
 	if (fd < 0) {
diff --git a/utils.c b/utils.c
index 6c09366..f760d1b 100644
--- a/utils.c
+++ b/utils.c
@@ -1377,19 +1377,43 @@  out:
 }
 
 static char *size_strs[] = { "", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB"};
+u64 forced_base = 0;
+int pretty_size_force_base(u64 base)
+{
+	u64 check = 1;
+	while (check < base)
+		check *= 1024;
+	if (check != base && base)
+		return -1;
+	forced_base = base;
+	return 0;
+}
 int pretty_size_snprintf(u64 size, char *str, size_t str_bytes)
 {
 	int num_divs = 0;
+	u64 last_size = size;
 	float fraction;
 
 	if (str_bytes == 0)
 		return 0;
 
-	if( size < 1024 ){
+	if( forced_base ){
+		u64 base = forced_base;
+		while (base > 1) {
+			base /= 1024;
+			last_size = size;
+			size /= 1024;
+			num_divs++;
+		}
+		if (num_divs < 2)
+			return snprintf(str, str_bytes, "%llu%s",
+					(unsigned long long)size,
+					size_strs[num_divs]);
+		goto check;
+	} else if( size < 1024 ){
 		fraction = size;
 		num_divs = 0;
 	} else {
-		u64 last_size = size;
 		num_divs = 0;
 		while(size >= 1024){
 			last_size = size;
@@ -1397,6 +1421,7 @@  int pretty_size_snprintf(u64 size, char *str, size_t str_bytes)
 			num_divs ++;
 		}
 
+	check:
 		if (num_divs >= ARRAY_SIZE(size_strs)) {
 			str[0] = '\0';
 			return -1;
diff --git a/utils.h b/utils.h
index fd25126..bbcb042 100644
--- a/utils.h
+++ b/utils.h
@@ -71,6 +71,7 @@  int check_mounted_where(int fd, const char *file, char *where, int size,
 int btrfs_device_already_in_root(struct btrfs_root *root, int fd,
 				 int super_offset);
 
+int pretty_size_force_base(u64 base);
 int pretty_size_snprintf(u64 size, char *str, size_t str_bytes);
 #define pretty_size(size) 						\
 	({								\