Hi all, this patch adds the command "btrfs filesystem label" to change (or show) the label of a filesystem. This patch is a subset of the one written previously by Morey Roof. I included the user space part only. So it is possible only to change/show a label of a *single device* and *unounted* filesystem.
The reason of excluding the kernel space part, is to simplify the patch in order to speed the check and then the merging of the patch itself. In fact I have to point out that in the past there was almost three attempts to propose this patch, without success neither complaints. Chris, let me know how you want to proceed. I know that you are very busy, and you prefer to work to stabilize btrfs instead adding new feature. But I think that changing a label is a *essential* feature for a filesystem managing tool. Think about a mount by LABEL. To show a label $ btrfs filesystem label <device> To set a label $ btrfs filesystem label <device> <newlabel> Please guys, give a look to the source. Comments are welcome. You can pull the source from the branch "label" of the repository http://cassiopea.homelinux.net/git/btrfs-progs-unstable.git Regards G.Baroncelli diff --git a/Makefile b/Makefile index 525676e..c06e512 100644 --- a/Makefile +++ b/Makefile @@ -4,7 +4,7 @@ CFLAGS = -g -Werror -Os objects = ctree.o disk-io.o radix-tree.o extent-tree.o print-tree.o \ root-tree.o dir-item.o file-item.o inode-item.o \ inode-map.o crc32c.o rbtree.o extent-cache.o extent_io.o \ - volumes.o utils.o btrfs-list.o + volumes.o utils.o btrfs-list.o btrfslabel.o # CHECKFLAGS=-D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ -Wbitwise \ diff --git a/btrfs.c b/btrfs.c index ab5e57f..ab0a9da 100644 --- a/btrfs.c +++ b/btrfs.c @@ -95,6 +95,10 @@ static struct Command commands[] = { "filesystem balance", "<path>\n" "Balance the chunks across the device." }, + { do_change_label, -1, + "filesystem label", "<device> [<label>]\n" + "Get or set a label of a filesystem." + }, { do_scan, 999, "device scan", "[<device> [<device>..]\n" "Scan all device for or the passed device for a btrfs\n" @@ -108,11 +112,6 @@ static struct Command commands[] = { "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 } }; diff --git a/btrfs_cmds.c b/btrfs_cmds.c index 8031c58..3f632c8 100644 --- a/btrfs_cmds.c +++ b/btrfs_cmds.c @@ -40,6 +40,7 @@ #include "volumes.h" #include "btrfs_cmds.h" +#include "btrfslabel.h" #ifdef __CHECKER__ #define BLKGETSIZE64 0 @@ -834,6 +835,21 @@ int do_set_default_subvol(int nargs, char **argv) return 0; } +int do_change_label(int nargs, char **argv) +{ + /* check the number of argument */ + if ( nargs > 3 ){ + fprintf(stderr, "ERROR: '%s' requires maximum 2 args\n", + argv[0]); + return -2; + }else if (nargs == 2){ + return get_label(argv[1]); + } else { /* nargs == 0 */ + return set_label(argv[1], argv[2]); + } +} + + 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..ab722d4 100644 --- a/btrfs_cmds.h +++ b/btrfs_cmds.h @@ -32,3 +32,4 @@ 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_find_newer(int argc, char **argv); +int do_change_label(int argc, char **argv); diff --git a/btrfslabel.c b/btrfslabel.c new file mode 100644 index 0000000..c9f4684 --- /dev/null +++ b/btrfslabel.c @@ -0,0 +1,121 @@ +/* + * Copyright (C) 2008 Morey Roof. All rights reserved. + * + * 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. + */ + +#define _GNU_SOURCE + +#ifndef __CHECKER__ +#include <sys/ioctl.h> +#include <sys/mount.h> +#include "ioctl.h" +#endif /* __CHECKER__ */ + +#include <stdio.h> +#include <stdlib.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <dirent.h> +#include <fcntl.h> +#include <unistd.h> +#include <linux/fs.h> +#include <linux/limits.h> +#include <ctype.h> +#include "kerncompat.h" +#include "ctree.h" +#include "utils.h" +#include "version.h" +#include "disk-io.h" +#include "transaction.h" + +#define MOUNTED 1 +#define UNMOUNTED 2 +#define GET_LABEL 3 +#define SET_LABEL 4 + +static void change_label_unmounted(char *dev, char *nLabel) +{ + struct btrfs_root *root; + struct btrfs_trans_handle *trans; + + /* Open the super_block at the default location + * and as read-write. + */ + root = open_ctree(dev, 0, 1); + + trans = btrfs_start_transaction(root, 1); + strncpy(root->fs_info->super_copy.label, nLabel, BTRFS_LABEL_SIZE); + btrfs_commit_transaction(trans, root); + + /* Now we close it since we are done. */ + close_ctree(root); +} + +static void get_label_unmounted(char *dev) +{ + struct btrfs_root *root; + + /* Open the super_block at the default location + * and as read-only. + */ + root = open_ctree(dev, 0, 0); + + fprintf(stdout, "%s\n", root->fs_info->super_copy.label); + + /* Now we close it since we are done. */ + close_ctree(root); +} + +int get_label(char *btrfs_dev) +{ + + int ret; + ret = check_mounted(btrfs_dev); + if (ret < 0) + { + fprintf(stderr, "FATAL: error checking %s mount status\n", btrfs_dev); + return -1; + } + + if(ret != 0) + { + fprintf(stderr, "FATAL: the filesystem has to be unmounted\n"); + return -2; + } + get_label_unmounted(btrfs_dev); + return 0; +} + + +int set_label(char *btrfs_dev, char *nLabel) +{ + + int ret; + ret = check_mounted(btrfs_dev); + if (ret < 0) + { + fprintf(stderr, "FATAL: error checking %s mount status\n", btrfs_dev); + return -1; + } + + if(ret != 0) + { + fprintf(stderr, "FATAL: the filesystem has to be unmounted\n"); + return -2; + } + change_label_unmounted(btrfs_dev, nLabel); + return 0; +} diff --git a/btrfslabel.h b/btrfslabel.h new file mode 100644 index 0000000..abf43ad --- /dev/null +++ b/btrfslabel.h @@ -0,0 +1,5 @@ +/* btrflabel.h */ + + +int get_label(char *btrfs_dev); +int set_label(char *btrfs_dev, char *nLabel); \ No newline at end of file diff --git a/man/btrfs.8.in b/man/btrfs.8.in index 26ef982..c1a8a42 100644 --- a/man/btrfs.8.in +++ b/man/btrfs.8.in @@ -21,6 +21,8 @@ btrfs \- control a btrfs filesystem .PP \fBbtrfs\fP \fBfilesystem resize\fP\fI [+/\-]<size>[gkm]|max <filesystem>\fP .PP +\fBbtrfs\fP \fBfilesystem label\fP\fI <dev> [newlabel]\fP +.PP \fBbtrfs\fP \fBdevice scan\fP\fI [<device> [<device>..]]\fP .PP \fBbtrfs\fP \fBdevice show\fP\fI <dev>|<label> [<dev>|<label>...]\fP @@ -138,6 +140,23 @@ can expand the partition before enlarging the filesystem and shrink the partition after reducing the size of the filesystem. .TP +\fBbtrfs\fP \fBfilesystem label\fP\fI <dev> [newlabel]\fP +Show or update the label of a filesystem. \fI<dev>\fR is used to identify the +filesystem. +If a \fInewlabel\fR optional argument is passed, the label is changed. The +following costraints exist for a label: +.IP +- the maximum allowable lenght shall be less or equal than 256 chars +.IP +- the label shall not contain the '/' or '\\' characters. + +NOTE: Currently there are the following limitations: +.IP +- the filesystem has to be unmounted +.IP +- the filesystem should not have more than one device. +.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. diff --git a/utils.c b/utils.c index 2f4c6e1..ea8e5b7 100644 --- a/utils.c +++ b/utils.c @@ -587,7 +587,7 @@ error: } /* - * returns 1 if the device was mounted, < 0 on error or 0 if everything + * returns 1 if the device is mounted, < 0 on error or 0 if everything * is safe to continue. TODO, this should also scan multi-device filesystems */ int check_mounted(char *file) @@ -638,6 +638,39 @@ int check_mounted(char *file) return ret; } +/* Gets the mount point of btrfs filesystem that is using the specified device. + * Returns 0 is everything is good, <0 if we have an error. + * TODO: Fix this fucntion and check_mounted to work with multiple drive BTRFS + * setups. + */ +int get_mountpt(char *dev, char *mntpt, size_t size) +{ + struct mntent *mnt; + FILE *f; + int ret = 0; + + f = setmntent("/proc/mounts", "r"); + if (f == NULL) + return -errno; + + while ((mnt = getmntent(f)) != NULL ) + { + if (strcmp(dev, mnt->mnt_fsname) == 0) + { + strncpy(mntpt, mnt->mnt_dir, size); + break; + } + } + + if (mnt == NULL) + { + /* We didn't find an entry so lets report an error */ + ret = -1; + } + + return ret; +} + struct pending_dir { struct list_head list; char name[256]; @@ -820,3 +853,27 @@ char *pretty_sizes(u64 size) return pretty; } +/* + * Checks to make sure that the label matches our requirements. + * Returns: + 0 if everything is safe and usable + -1 if the label is too long + -2 if the label contains an invalid character + */ +int check_label(char *input) +{ + int i; + int len = strlen(input); + + if (len > BTRFS_LABEL_SIZE) { + return -1; + } + + for (i = 0; i < len; i++) { + if (input[i] == '/' || input[i] == '\\') { + return -2; + } + } + + return 0; +} diff --git a/utils.h b/utils.h index 7ff542b..838b65e 100644 --- a/utils.h +++ b/utils.h @@ -40,4 +40,6 @@ int check_mounted(char *devicename); int btrfs_device_already_in_root(struct btrfs_root *root, int fd, int super_offset); char *pretty_sizes(u64 size); +int check_label(char *input); +int get_mountpt(char *dev, char *mntpt, size_t size); #endif -- gpg key@ keyserver.linux.it:Goffredo Baroncelli (ghigo) <kreijackATinwind.it> Key fingerprint = 4769 7E51 5293 D36C 814E C054 BF04 F161 3DC5 0512
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