Update/clean up btrfs help and man page V2

Hi all,

enclose you can find a patch which improves the help of the btrfs commands,
 updates the INSTALL file  and  the btrfs (command) man page.

Regarding the help of the btrfs command:
- moved the "subvolume set-default" command in the "subvolume" commands group
- removed a wrong new line
- small tweak on the basis of Andreas suggestion

Regarding the btrfs command man page:
- renaming the command "device balance" in "filesystem balance" (thanks to
Andreas Phillipp to highlight that)
- adding the entry "subvolume find-new"
- document the switches of the command "filesystem defrag"
- document the <devid> facility of the command "filesystem resize"
- small tweak on the basis of Andreas suggestion

Regarding the INSTALL file, which was very old, I removed the reference of the
old btrfsctl utility and changed the examples using the btrfs command.
I removed the old (and now wrong) statement about the inability to delete a
subvolume/snapshot

Chris, you can pull the patch from the branch "help_cleanup" of the following
repository.

http://cassiopea.homelinux.net/git/btrfs-progs-unstable.git

(or you can browse the changes at
http://cassiopea.homelinux.net/git/btrfs-progs-unstable.git/?p=btrfs-
progs-unstable-all.git;a=summary)

The patch is very simple: only updates the man page, the INSTALL file and
 moves/updates some lines in the help of btrfs command. Comments are welcome.

Regards
G.Baroncelli

 INSTALL        |   29 ++++++++++++++++++++---------
 btrfs.c        |   24 ++++++++++++------------
 man/btrfs.8.in |   45 +++++++++++++++++++++++++--------------------
 3 files changed, 57 insertions(+), 41 deletions(-)

 all the block devices.
 .TP
@@ -138,21 +143,21 @@ can expand the partition before enlarging the filesystem
and shrink the
 partition after reducing the size of the filesystem.
 .TP

-\fBfilesystem show\fR [<uuid>|<label>]\fR
-Show the btrfs filesystem with some additional info. If no UUID or label is
-passed, \fBbtrfs\fR show info of all the btrfs filesystem.
+\fBfilesystem show\fR [<device>|<uuid>|<label>]\fR
+Show the btrfs filesystem with some additional info. If no argument is
+passed, \fBbtrfs\fR shows info of all the btrfs filesystems.
 .TP

-\fBdevice balance\fR \fI<path>\fR
+\fBfilesystem balance\fR \fI<path>\fR
 Balance the chunks of the filesystem identified by \fI<path>\fR
 across the devices.
 .TP

-\fBdevice add\fR\fI <dev> [<dev>..] <path>\fR
+\fBdevice add\fR\fI <device> [<device>...] <path>\fR
 Add device(s) to the filesystem identified by \fI<path>\fR.
 .TP

-\fBdevice delete\fR\fI <dev> [<dev>..] <path>\fR
+\fBdevice delete\fR\fI <device> [<device>...] <path>\fR
 Remove device(s) from a filesystem identified by \fI<path>\fR.
 .PP

Signed-off-by: Chris Mason <chris.mason@oracle.com>

INSTALL

@@ -22,23 +22,32 @@ in the e2fsprogs sources, and is usually available as libuuid or
 e2fsprogs-devel from various distros.
 
 Building the utilities is just make ; make install.  The programs go
-into /usr/local/bin.  The commands available are:
+into /usr/local/bin.  The mains commands available are:
 
 mkfs.btrfs: create a filesystem
 
-btrfsctl: control program to create snapshots and subvolumes:
-
+btrfs: control program to create snapshots and subvolumes:
+	# mount a btrfs filesystem
 	mount /dev/sda2 /mnt
-	btrfsctl -s new_subvol_name /mnt
-	btrfsctl -s snapshot_of_default /mnt/default
-	btrfsctl -s snapshot_of_new_subvol /mnt/new_subvol_name
-	btrfsctl -s snapshot_of_a_snapshot /mnt/snapshot_of_new_subvol
+
+	# create a subvolume
+	btrfs subvolume create /mnt/new_subvol_name
+
+	# snapshot of a subvolume
+	btrfs subvolume snapshot /mnt/default /mnt/snapshot_of_default 
+	btrfs subvolume snapshot /mnt/snapshot_of_default \
+		/mnt/snapshot_of_a_snapshot
+
+	# list of the subvolumes
 	ls /mnt
 	default snapshot_of_a_snapshot snapshot_of_new_subvol
 	new_subvol_name snapshot_of_default
 
-	Snapshots and subvolumes cannot be deleted right now, but you can
-	rm -rf all the files and directories inside them.
+	# removal of a subvolume or a snapshot
+	btrfs subvolume delete /mn/snapshot_of_a_snapshot
+
+	# look a the btrfs man page for further information
+	man btrfs
 
 btrfsck: do a limited check of the FS extent trees.</li>
 
@@ -46,3 +55,5 @@ debug-tree: print all of the FS metadata in text form.  Example:
 
 	debug-tree /dev/sda2 >& big_output_file
 
+
+

btrfs.c

@@ -61,6 +61,11 @@ static struct Command commands[] = {
 	{ do_subvol_list, 1, "subvolume list", "<path>\n"
 		"List the snapshot/subvolume of a filesystem."
 	},
+	{ do_set_default_subvol, 2,
+	  "subvolume set-default", "<id> <path>\n"
+		"Set the subvolume of the filesystem <path> which will be mounted\n"
+		"as default."
+	},
 	{ do_find_newer, 2, "subvolume find-new", "<path> <last_gen>\n"
 		"List the recently modified files in a filesystem."
 	},
@@ -68,11 +73,6 @@ static struct Command commands[] = {
 	  "filesystem defragment", "[-vf] [-c[zlib,lzo]] [-s start] [-l len] [-t size] <file>|<dir> [<file>|<dir>...]\n"
 		"Defragment a file or a directory."
 	},
-	{ do_set_default_subvol, 2,
-	  "subvolume set-default", "<id> <path>\n"
-		"Set the subvolume of the filesystem <path> which will be mounted\n"
-		"as default."
-	},
 	{ do_fssync, 1,
 	  "filesystem sync", "<path>\n"
 		"Force a sync on the filesystem <path>."
@@ -83,29 +83,29 @@ static struct Command commands[] = {
 		"will occupe all available space on the device."
 	},
 	{ do_show_filesystem, 999,
-	  "filesystem show", "[<uuid>|<label>]\n"
-		"Show the info of a btrfs filesystem. If no <uuid> or <label>\n"
+	  "filesystem show", "[<device>|<uuid>|<label>]\n"
+		"Show the info of a btrfs filesystem. If no argument\n"
 		"is passed, info of all the btrfs filesystem are shown."
 	},
 	{ do_df_filesystem, 1,
 	  "filesystem df", "<path>\n"
-		"Show space usage information for a mount point\n."
+		"Show space usage information for a mount point."
 	},
 	{ do_balance, 1,
 	  "filesystem balance", "<path>\n"
 		"Balance the chunks across the device."
 	},
-	{ do_scan,
-	  999, "device scan", "[<device> [<device>..]\n"
+	{ do_scan, 999, 
+	  "device scan", "[<device>...]\n"
 		"Scan all device for or the passed device for a btrfs\n"
 		"filesystem."
 	},
 	{ do_add_volume, -2,
-	  "device add", "<dev> [<dev>..] <path>\n"
+	  "device add", "<device> [<device>...] <path>\n"
 		"Add a device to a filesystem."
 	},
 	{ do_remove_volume, -2,
-	  "device delete", "<dev> [<dev>..] <path>\n"
+	  "device delete", "<device> [<device>...] <path>\n"
 		"Remove a device from a filesystem."
 	},
 	/* coming soon

man/btrfs.8.in

@@ -21,15 +21,19 @@ btrfs \- control a btrfs filesystem
 .PP
 \fBbtrfs\fP \fBfilesystem defrag\fP\fI [options] <file>|<dir> [<file>|<dir>...]\fP
 .PP
-\fBbtrfs\fP \fBdevice scan\fP\fI [<device> [<device>..]]\fP
+\fBbtrfs\fP \fBsubvolume find-new\fP\fI <subvolume> <last_gen>\fP
 .PP
-\fBbtrfs\fP \fBdevice show\fP\fI <dev>|<label> [<dev>|<label>...]\fP
+\fBbtrfs\fP \fBfilesystem balance\fP\fI <path> \fP
 .PP
-\fBbtrfs\fP \fBdevice balance\fP\fI <path> \fP
+\fBbtrfs\fP \fBfilesystem defragment\fP\fI <file>|<dir> [<file>|<dir>...]\fP
 .PP
-\fBbtrfs\fP \fBdevice add\fP\fI <dev> [<dev>..] <path> \fP
+\fBbtrfs\fP \fBdevice scan\fP\fI [<device>...]\fP
 .PP
-\fBbtrfs\fP \fBdevice delete\fP\fI <dev> [<dev>..] <path> \fP]
+\fBbtrfs\fP \fBdevice show\fP\fI [<device>|<uuid>|<label>]\fP
+.PP
+\fBbtrfs\fP \fBdevice add\fP\fI <device> [<device>...] <path> \fP
+.PP
+\fBbtrfs\fP \fBdevice delete\fP\fI <device> [<device>...] <path> \fP]
 .PP
 \fBbtrfs\fP \fBhelp|\-\-help|\-h \fP\fI\fP
 .PP
@@ -48,17 +52,16 @@ For example: it is possible to run
 instead of
 .I btrfs subvolume snapshot.
 But
-.I btrfs dev s
+.I btrfs file s
 is not allowed, because
-.I dev s
+.I file s
 may be interpreted both as
-.I device show
+.I filesystem show
 and as
-.I device scan.
+.I filesystem sync.
 In this case
 .I btrfs
-returns an error.
-
+returnsfilesystem sync
 If a command is terminated by
 .I --help
 , the detailed help is showed. If the passed command matches more commands,
@@ -125,9 +128,11 @@ The start position and the number of bytes to deframention can be specified by \
 NOTE: defragmenting with kernels up to 2.6.37 will unlink COW-ed copies of data, don't 
 use it if you use snapshots, have de-duplicated your data or made copies with 
 \fBcp --reflink\fP.
+\fBsubvolume find-new\fR\fI <subvolume> <last_gen>\fR
+List the recently modified files in a subvolume, after \fI<last_gen>\fR ID.
 .TP
 
-\fBdevice scan\fR \fI[<device> [<device>..]]\fR
+\fBdevice scan\fR \fI[<device>...]\fR
 Scan devices for a btrfs filesystem. If no devices are passed, \fBbtrfs\fR scans
 all the block devices.
 .TP