new util: 'btrfs'

This commit introduces a new command called 'btrfs' for managing
a btrfs filesystem. 'btrfs' handles:
- snapshot/subvolume creation
- adding/removal of volume (ie: disk)
- defragment of a tree
- scan of a device searching a btrfs filesystem
- re-balancing of the chunk on the disks
- listing subvolumes and snapshots

This has also been updated to include the new defrag range ioctl.

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

1 files changed, 335 insertions, 0 deletions

diff --git a/btrfs.c b/btrfs.c
new file mode 100644
index 00000000..20f74134
--- /dev/null
+++ b/btrfs.c
@@ -0,0 +1,335 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "btrfs_cmds.h"
+#include "version.h"
+
+typedef int (*CommandFunction)(int argc, char **argv);
+
+struct Command {
+	CommandFunction	func;	/* function which implements the command */
+	int	nargs;		/* if == 999, any number of arguments
+				   if >= 0, number of arguments,
+				   if < 0, _minimum_ number of arguments */
+	char	*verb;		/* verb */
+	char	*help;		/* help lines; form the 2nd onward they are
+				   indented */
+
+	/* the following fields are run-time filled by the program */
+	char	**cmds;		/* array of subcommands */
+	int	ncmds;		/* number of subcommand */
+};
+
+static struct Command commands[] = {
+
+	/*
+		avoid short commands different for the case only
+	*/
+	{ do_clone, 2,
+	  "subvolume snapshot", "<source> [<dest>/]<name>\n"
+		"Create a writable snapshot of the subvolume <source> with\n"
+		"the name <name> in the <dest> directory."
+	},
+	{ do_delete_subvolume, 1,
+	  "subvolume delete", "<subvolume>\n"
+		"Delete the subvolume <subvolume>."
+	},
+	{ do_create_subvol, 1,
+	  "subvolume create", "[<dest>/]<name>\n"
+		"Create a subvolume in <dest> (or the current directory if\n"
+		"not passed)."
+	},
+	{ do_subvol_list, 1, "subvolume list", "<path>\n"
+		"List the snapshot/subvolume of a filesystem."
+	},
+
+	{ do_defrag, -1,
+	  "filesystem defragment", "[-vcf] [-s start] [-l len] [-t size] <file>|<dir> [<file>|<dir>...]\n"
+		"Defragment a file or a directory."
+	},
+	{ do_fssync, 1,
+	  "filesystem sync", "<path>\n"
+		"Force a sync on the filesystem <path>."
+	},
+	{ do_resize, 2,
+	  "filesystem resize", "[+/-]<newsize>[gkm]|max <filesystem>\n"
+		"Resize the file system. If 'max' is passed, the filesystem\n"
+		"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"
+		"is passed, info of all the btrfs filesystem are shown."
+	},
+	{ do_balance, 1,
+	  "filesystem balance", "<path>\n"
+		"Balance the chunks across the device."
+	},
+	{ do_scan,
+	  999, "device scan", "[<device> [<device>..]\n"
+		"Scan all device for or the passed device for a btrfs\n"
+		"filesystem."
+	},
+	{ do_add_volume, -1,
+	  "device add", "<dev> [<dev>..] <path>\n"
+		"Add a device to a filesystem."
+	},
+	{ do_remove_volume, -1,
+	  "device delete", "<dev> [<dev>..] <path>\n"
+		"Remove a device from a filesystem."
+	},
+	/* coming soon
+	{ 2, "filesystem label", "<label> <path>\n"
+		"Set the label of a filesystem"
+	}
+	*/
+	{ 0, 0 , 0 }
+};
+
+static char *get_prgname(char *programname)
+{
+	char	*np;
+	np = strrchr(programname,'/');
+	if(!np)
+		np = programname;
+	else
+		np++;
+
+	return np;
+}
+
+static void print_help(char *programname, struct Command *cmd)
+{
+	char	*pc;
+
+	printf("\t%s %s ", programname, cmd->verb );
+
+	for(pc = cmd->help; *pc; pc++){
+		putchar(*pc);
+		if(*pc == '\n')
+			printf("\t\t");
+	}
+	putchar('\n');
+}
+
+static void help(char *np)
+{
+	struct Command *cp;
+
+	printf("Usage:\n");
+	for( cp = commands; cp->verb; cp++ )
+		print_help(np, cp);
+
+	printf("\n\t%s help|--help|-h\n\t\tShow the help.\n",np);
+	printf("\n%s\n", BTRFS_BUILD_VERSION);
+}
+
+static int split_command(char *cmd, char ***commands)
+{
+	int	c, l;
+	char	*p, *s;
+
+	for( *commands = 0, l = c = 0, p = s = cmd ; ; p++, l++ ){
+		if ( *p && *p != ' ' )
+			continue;
+
+		/* c + 2 so that we have room for the null */
+		(*commands) = realloc( (*commands), sizeof(char *)*(c + 2));
+		(*commands)[c] = strndup(s, l);
+		c++;
+		l = 0;
+		s = p+1;
+		if( !*p ) break;
+	}
+
+	(*commands)[c] = 0;
+	return c;
+}
+
+/*
+	This function checks if the passed command is ambiguous
+*/
+static int check_ambiguity(struct Command *cmd, char **argv){
+	int		i;
+	struct Command	*cp;
+	/* check for ambiguity */
+	for( i = 0 ; i < cmd->ncmds ; i++ ){
+		int match;
+		for( match = 0, cp = commands; cp->verb; cp++ ){
+			int	j, skip;
+			char	*s1, *s2;
+
+			if( cp->ncmds < i )
+				continue;
+
+			for( skip = 0, j = 0 ; j < i ; j++ )
+				if( strcmp(cmd->cmds[j], cp->cmds[j])){
+					skip=1;
+					break;
+				}
+			if(skip)
+				continue;
+
+			if( !strcmp(cmd->cmds[i], cp->cmds[i]))
+				continue;
+			for(s2 = cp->cmds[i], s1 = argv[i+1];
+				*s1 == *s2 && *s1; s1++, s2++ ) ;
+			if( !*s1 )
+				match++;
+		}
+		if(match){
+			int j;
+			fprintf(stderr, "ERROR: in command '");
+			for( j = 0 ; j <= i ; j++ )
+				fprintf(stderr, "%s%s",j?" ":"", argv[j+1]);
+			fprintf(stderr, "', '%s' is ambiguous\n",argv[j]);
+			return -2;
+		}
+	}
+	return 0;
+}
+
+/*
+
+	This function perform the following jobs:
+	- show the help if '--help' or 'help' or '-h' are passed
+	- verify that a command is not ambiguous, otherwise show which
+	  part of the command is ambiguous
+	- if after a (even partial) command there is '--help' show the help
+	  for all the matching commands
+	- if the command doesn't' match show an error
+	- finally, if a command match, they return which command is matched and
+	  the arguments
+
+	The function return 0 in case of help is requested; <0 in case
+	of uncorrect command; >0 in case of matching commands
+	argc, argv are the arg-counter and arg-vector (input)
+	*nargs_ is the number of the arguments after the command (output)
+	**cmd_  is the invoked command (output)
+	***args_ are the arguments after the command
+
+*/
+static int parse_args(int argc, char **argv,
+		      CommandFunction *func_,
+		      int *nargs_, char **cmd_, char ***args_ )
+{
+	struct Command	*cp;
+	struct Command	*matchcmd=0;
+	char		*prgname = get_prgname(argv[0]);
+	int		i=0, helprequested=0;
+
+	if( argc < 2 || !strcmp(argv[1], "help") ||
+		!strcmp(argv[1], "-h") || !strcmp(argv[1], "--help")){
+		help(prgname);
+		return 0;
+	}
+
+	for( cp = commands; cp->verb; cp++ )
+		if( !cp->ncmds)
+			cp->ncmds = split_command(cp->verb, &(cp->cmds));
+
+	for( cp = commands; cp->verb; cp++ ){
+		int     match;
+
+		if( argc-1 < cp->ncmds )
+			continue;
+		for( match = 1, i = 0 ; i < cp->ncmds ; i++ ){
+			char	*s1, *s2;
+			s1 = cp->cmds[i];
+			s2 = argv[i+1];
+
+			for(s2 = cp->cmds[i], s1 = argv[i+1];
+				*s1 == *s2 && *s1;
+				s1++, s2++ ) ;
+			if( *s1 ){
+				match=0;
+				break;
+			}
+		}
+
+		/* If you understand why this code works ...
+			you are a genious !! */
+		if(argc>i+1 && !strcmp(argv[i+1],"--help")){
+			if(!helprequested)
+				printf("Usage:\n");
+			print_help(prgname, cp);
+			helprequested=1;
+			continue;
+		}
+
+		if(!match)
+			continue;
+
+		matchcmd = cp;
+		*nargs_  = argc-matchcmd->ncmds-1;
+		*cmd_ = matchcmd->verb;
+		*args_ = argv+matchcmd->ncmds+1;
+		*func_ = cp->func;
+
+		break;
+	}
+
+	if(helprequested){
+		printf("\n%s\n", BTRFS_BUILD_VERSION);
+		return 0;
+	}
+
+	if(!matchcmd){
+		fprintf( stderr, "ERROR: unknown command '%s'\n",argv[1]);
+		help(prgname);
+		return -1;
+	}
+
+	if(check_ambiguity(matchcmd, argv))
+		return -2;
+
+	/* check the number of argument */
+	if (matchcmd->nargs < 0 && matchcmd->nargs < -*nargs_ ){
+		fprintf(stderr, "ERROR: '%s' requires minimum %d arg(s)\n",
+			matchcmd->verb, -matchcmd->nargs);
+			return -2;
+	}
+	if(matchcmd->nargs >= 0 && matchcmd->nargs != *nargs_ && matchcmd->nargs != 999 ){
+		fprintf(stderr, "ERROR: '%s' requires %d arg(s)\n",
+			matchcmd->verb, matchcmd->nargs);
+			return -2;
+	}
+
+	return 1;
+}
+
+int main(int ac, char **av )
+{
+
+	char		*cmd=0, **args=0;
+	int		nargs=0, r;
+	CommandFunction func=0;
+
+	r = parse_args(ac, av, &func, &nargs, &cmd, &args);
+	if( r <= 0 ){
+		/* error or no command to parse*/
+		exit(-r);
+	}
+
+	exit(func(nargs, args));
+
+}
+