Miao Xie
2012-May-31 10:28 UTC
[PATCH] Btrfs-progs: Update mtab if necessary when device was deleted in btrfs
Now if we remove the device that is specified when mounting, btrfs will update
the mount information in /proc, such as the information in /proc/mounts. So
in order to guarantee the consistency between /etc/mtab and the mount
information in /proc, we must update /etc/mtab. This patch does it.
This patch need libmount and libmount-devel(version >= 2.19) packages to
compile.
Signed-off-by: Chen Yang <chenyang.fnst@cn.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
---
Makefile | 2 +-
cmds-device.c | 404 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
utils.h | 1 +
3 files changed, 399 insertions(+), 8 deletions(-)
diff --git a/Makefile b/Makefile
index 79818e6..8ce415b 100644
--- a/Makefile
+++ b/Makefile
@@ -15,7 +15,7 @@ DEPFLAGS = -Wp,-MMD,$(@D)/.$(@F).d,-MT,$@
INSTALL = install
prefix ?= /usr/local
bindir = $(prefix)/bin
-LIBS=-luuid
+LIBS=-luuid -lmount
RESTORE_LIBS=-lz
progs = btrfsctl mkfs.btrfs btrfs-debug-tree btrfs-show btrfs-vol btrfsck \
diff --git a/cmds-device.c b/cmds-device.c
index db625a6..bdafebe 100644
--- a/cmds-device.c
+++ b/cmds-device.c
@@ -13,7 +13,7 @@
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
-
+#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@@ -22,6 +22,7 @@
#include <sys/ioctl.h>
#include <errno.h>
#include <sys/stat.h>
+#include <paths.h>
#include "kerncompat.h"
#include "ctree.h"
@@ -29,6 +30,7 @@
#include "utils.h"
#include "commands.h"
+#include <libmount/libmount.h>
/* FIXME - imported cruft, fix sparse errors and warnings */
#ifdef __CHECKER__
@@ -39,6 +41,10 @@ struct btrfs_ioctl_vol_args { char name[BTRFS_VOL_NAME_MAX];
};
static inline int ioctl(int fd, int define, void *arg) { return 0; }
#endif
+#define PROC_MOUNTS_PATH "/proc/mounts"
+int mtab_is_regular;
+struct libmnt_lock *volatile mtab_lock;
+
static const char * const device_cmd_group_usage[] = {
"btrfs device <command> [<args>]",
NULL
@@ -50,10 +56,312 @@ static const char * const cmd_add_dev_usage[] = {
NULL
};
+static int mtab_fprintf_fs(FILE *f, struct libmnt_fs *fs)
+{
+ const char *src, *fstype;
+ char *o;
+ char *m1, *m2, *m3, *m4;
+ int ret;
+
+ assert(fs);
+ assert(f);
+
+ src = mnt_fs_get_source(fs);
+ fstype = mnt_fs_get_fstype(fs);
+ o = mnt_fs_strdup_options(fs);
+ if (!o)
+ return -ENOMEM;
+
+ m1 = src ? mnt_mangle(src) : "none";
+ m2 = mnt_mangle(mnt_fs_get_target(fs));
+ m3 = fstype ? mnt_mangle(fstype) : "none";
+ m4 = o ? mnt_mangle(o) : "rw";
+
+ if (m1 && m2 && m3 && m4) {
+ ret = fprintf(f, "%s %s %s %s %d %d\n",
+ m1, m2, m3, m4,
+ mnt_fs_get_freq(fs),
+ mnt_fs_get_passno(fs));
+ if (ret > 0)
+ ret = 0;
+ } else
+ ret = -ENOMEM;
+
+ if (src)
+ mnt_unmangle(m1);
+ mnt_unmangle(m2);
+ if (fstype)
+ mnt_unmangle(m3);
+ if (o)
+ mnt_unmangle(m4);
+ free(o);
+
+ return ret;
+}
+
+static int mtab_open_uniq_filename(const char *filename, char **name)
+{
+ int fd;
+ char *n;
+ int ret;
+
+ assert(filename);
+
+ if (name)
+ *name = NULL;
+
+ ret = asprintf(&n, "%s.XXXXXX", filename);
+ if (ret <= 0)
+ return -errno;
+
+ fd = mkstemp(n);
+ if (fd >= 0 && name)
+ *name = n;
+ else
+ free(n);
+
+ return fd < 0 ? -errno : fd;
+}
+
+static int mtab_update_table(struct libmnt_table *tb)
+{
+ FILE *f;
+ int fd;
+ char *uq = NULL;
+ int ret;
+
+ if (!tb)
+ return -EINVAL;
+
+ fd = mtab_open_uniq_filename(_PATH_MOUNTED, &uq);
+ if (fd < 0)
+ return fd; /* error */
+
+ f = fdopen(fd, "w");
+ if (f) {
+ struct stat st;
+ struct libmnt_iter *itr;
+ struct libmnt_fs *fs;
+ int fd;
+
+ itr = mnt_new_iter(MNT_ITER_FORWARD);
+ if (!itr) {
+ ret = -ENOMEM;
+ goto leave;
+ }
+
+ while (mnt_table_next_fs(tb, itr, &fs) == 0) {
+ ret = mtab_fprintf_fs(f, fs);
+ if (ret) {
+ mnt_free_iter(itr);
+ goto leave;
+ }
+ }
+ mnt_free_iter(itr);
+
+ if (fflush(f) != 0) {
+ ret = -errno;
+ goto leave;
+ }
+
+ fd = fileno(f);
+ ret = fchmod(fd, S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH) ? -errno : 0;
+
+ if (!ret && stat(_PATH_MOUNTED, &st) == 0)
+ ret = fchown(fd, st.st_uid, st.st_gid) ? -errno : 0;
+
+ fclose(f);
+ ret = rename(uq, _PATH_MOUNTED) ? -errno : 0;
+ } else {
+ ret = -errno;
+ close(fd);
+ }
+
+leave:
+ unlink(uq); /* be paranoid */
+ free(uq);
+ return ret;
+}
+
+static int btrfs_get_all_devices(const char *devname,
+ struct btrfs_fs_devices **fs_devices_ret)
+{
+ int fd;
+ int ret;
+
+ fd = open(devname, O_RDONLY);
+ if (fd < 0) {
+ fprintf(stderr,
+ "Error: btrfs_get_all_devices() Could not open %s\n",
+ devname);
+ return -errno;
+ }
+
+ ret = check_mounted_where(fd, devname, NULL, 0, fs_devices_ret);
+ close(fd);
+ if (ret == 0) {
+ fprintf(stderr,
+ "Error: This device(%s) is not in this fs.\n", devname);
+ return -EINVAL;
+ } else if (ret > 0)
+ ret = 0;
+
+ return ret;
+}
+
+void clean_lock(void)
+{
+ if (!mtab_lock)
+ return;
+ mnt_unlock_file(mtab_lock);
+ mnt_free_lock(mtab_lock);
+}
+
+static int mtab_prepare_update(void)
+{
+ mtab_is_regular = mnt_has_regular_mtab(NULL, NULL);
+ if (!mtab_is_regular)
+ return 0;
+
+ mtab_lock = mnt_new_lock(_PATH_MOUNTED, 0);
+ if (!mtab_lock)
+ return -errno;
+
+ atexit(clean_lock);
+ mnt_lock_block_signals(mtab_lock, 1);
+
+ if (mnt_lock_file(mtab_lock) != 0) {
+ fprintf(stderr, "Error: prepare lock mtab failed.\n");
+ mnt_free_lock(mtab_lock);
+ mtab_lock = NULL;
+ return -1;
+ }
+
+ return 0;
+}
+
+struct match_data {
+ struct btrfs_fs_devices *fs_devices;
+ const char *target;
+};
+
+static int match_mounts_fs(struct libmnt_fs *fs, void *data)
+{
+ struct match_data *match_data = data;
+ int ret;
+
+ ret = blk_file_in_dev_list(match_data->fs_devices,
+ mnt_fs_get_source(fs));
+ if (!ret)
+ return 0;
+
+ ret = strcmp(match_data->target, mnt_fs_get_target(fs));
+ if (ret)
+ return 0;
+
+ return 1;
+}
+
+static int match_mtab_fs(struct libmnt_fs *fs, void *data)
+{
+ struct btrfs_fs_devices *fs_devices = data;
+ int ret;
+
+ ret = blk_file_in_dev_list(fs_devices, mnt_fs_get_source(fs));
+
+ return ret;
+}
+
+static int mtab_do_update(struct btrfs_fs_devices *fs_devices)
+{
+ struct libmnt_table *mounts_tb = NULL, *mtab_tb = NULL;
+ struct libmnt_fs *mounts_fs = NULL, *mtab_fs = NULL;
+ struct libmnt_iter *mounts_itr = NULL, *mtab_itr = NULL;
+ struct match_data data;
+ const char *type;
+ int ret;
+
+ if (!mtab_is_regular)
+ return 0;
+
+ mounts_tb = mnt_new_table_from_file(PROC_MOUNTS_PATH);
+ if (!mounts_tb)
+ return -ENOMEM;
+
+ mtab_tb = mnt_new_table_from_file(_PATH_MOUNTED);
+ if (!mtab_tb) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ mtab_itr = mnt_new_iter(MNT_ITER_FORWARD);
+ if (!mtab_itr) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ mounts_itr = mnt_new_iter(MNT_ITER_FORWARD);
+ if (!mounts_itr) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ data.fs_devices = fs_devices;
+
+ ret = mnt_table_find_next_fs(mtab_tb, mtab_itr, match_mtab_fs,
+ fs_devices, &mtab_fs);
+ while (!ret) {
+ type = mnt_fs_get_fstype(mtab_fs);
+ if (strcmp(type, "btrfs"))
+ BUG();
+
+ data.target = mnt_fs_get_target(mtab_fs);
+ ret = mnt_table_find_next_fs(mounts_tb, mounts_itr,
+ match_mounts_fs,
+ &data, &mounts_fs);
+ /*
+ * It is impossble that we can not find the relative fs
+ * in /proc/mounts.
+ */
+ if (ret)
+ BUG();
+
+ ret = mnt_fs_set_source(mtab_fs, mnt_fs_get_source(mounts_fs));
+ if (ret)
+ goto out;
+
+ mnt_reset_iter(mounts_itr, MNT_ITER_FORWARD);
+ ret = mnt_table_find_next_fs(mtab_tb, mtab_itr, match_mtab_fs,
+ fs_devices, &mtab_fs);
+ }
+
+ ret = mtab_update_table(mtab_tb);
+out:
+ mnt_free_iter(mtab_itr);
+ mnt_free_iter(mounts_itr);
+ mnt_free_table(mtab_tb);
+ mnt_free_table(mounts_tb);
+
+ return ret;
+}
+
+static void mtab_end_update(void)
+{
+ if (!mtab_is_regular)
+ return;
+
+ mnt_unlock_file(mtab_lock);
+ mnt_free_lock(mtab_lock);
+ mtab_lock = NULL;
+}
+
static int cmd_add_dev(int argc, char **argv)
{
+ struct btrfs_fs_devices *fs_devices = NULL;
char *mntpnt;
int i, fdmnt, ret=0, e;
+ /* the index of the device that is successful to be add into fs */
+ int index = 0;
if (check_argc_min(argc, 3))
usage(cmd_add_dev_usage);
@@ -66,6 +374,13 @@ static int cmd_add_dev(int argc, char **argv)
return 12;
}
+ ret = mtab_prepare_update();
+ if (ret) {
+ fprintf(stderr, "Error: prepare update failed.\n");
+ ret = 12;
+ goto out;
+ }
+
for (i = 1; i < argc - 1; i++ ){
struct btrfs_ioctl_vol_args ioctl_args;
int devfd, res;
@@ -119,14 +434,45 @@ static int cmd_add_dev(int argc, char **argv)
strncpy(ioctl_args.name, argv[i], BTRFS_PATH_NAME_MAX);
res = ioctl(fdmnt, BTRFS_IOC_ADD_DEV, &ioctl_args);
e = errno;
- if(res<0){
+ if (res < 0) {
fprintf(stderr, "ERROR: error adding the device ''%s''
- %s\n",
argv[i], strerror(e));
ret++;
+ } else if (!index) {
+ index = i;
}
+ }
+ /* There is no device which is add into fs. */
+ if (!index)
+ goto end_update;
+
+ /*
+ * index indicates the device that is successful to be add into the
+ * specified fs. And we will get all devices in the specified fs by
+ * this device, then we will use this device information to check if
+ * the item in mtab or /proc/mounts is relative to the specified fs
+ * or not. This is tricky.
+ */
+ e = btrfs_get_all_devices(argv[index], &fs_devices);
+ if (e) {
+ fprintf(stderr, "ERROR: Get all the devices failed - %s\n",
+ strerror(e));
+ if (!ret)
+ ret = 12;
+ goto end_update;
}
+ e = mtab_do_update(fs_devices);
+ if (e) {
+ fprintf(stderr, "ERROR: update /etc/mtab failed - %s\n",
+ strerror(e));
+ if (!ret)
+ ret = 12;
+ }
+end_update:
+ mtab_end_update();
+out:
close(fdmnt);
if (ret)
return ret+20;
@@ -142,8 +488,11 @@ static const char * const cmd_rm_dev_usage[] = {
static int cmd_rm_dev(int argc, char **argv)
{
+ struct btrfs_fs_devices *fs_devices = NULL;
char *mntpnt;
int i, fdmnt, ret=0, e;
+ /* The index of the device that is removed from fs. */
+ int index = 0;
if (check_argc_min(argc, 3))
usage(cmd_rm_dev_usage);
@@ -156,23 +505,65 @@ static int cmd_rm_dev(int argc, char **argv)
return 12;
}
+ ret = mtab_prepare_update();
+ if (ret) {
+ fprintf(stderr, "Error: prepare update failed.\n");
+ ret = 12;
+ goto out;
+ }
+
for(i=1 ; i < argc - 1; i++ ){
struct btrfs_ioctl_vol_args arg;
int res;
+ /*
+ * We need the device information to check the item in mtab
+ * or /proc/mounts is relative to the specified fs or not.
+ * But it is a little hard to get it because we doesn''t have
+ * a suitable interface in the kernel.
+ *
+ * Fortunately, there is a tricky way to achieve it. That is
+ * reusing the function check_mounted_where(). If one device
+ * is in the specified fs, we can get all the devices by this
+ * function and this device.
+ */
+ if (!index) {
+ e = btrfs_get_all_devices(argv[i], &fs_devices);
+ if (e) {
+ ret++;
+ continue;
+ }
+ }
+
strncpy(arg.name, argv[i], BTRFS_PATH_NAME_MAX);
res = ioctl(fdmnt, BTRFS_IOC_RM_DEV, &arg);
e = errno;
- if(res<0){
- fprintf(stderr, "ERROR: error removing the device
''%s'' - %s\n",
+ if (res < 0) {
+ fprintf(stderr,
+ "ERROR: error removing the device ''%s'' - %s\n",
argv[i], strerror(e));
ret++;
+ } else if (!index) {
+ index = i;
}
}
+ if (!index)
+ goto end_update;
+
+ e = mtab_do_update(fs_devices);
+ if (e) {
+ fprintf(stderr, "ERROR: update /etc/mtab failed - %s\n",
+ strerror(e));
+ if (!ret)
+ ret = 12;
+ }
+end_update:
+ mtab_end_update();
+out:
close(fdmnt);
- if( ret)
- return ret+20;
+ if (ret)
+ return ret + 20;
else
return 0;
}
@@ -198,7 +589,6 @@ static int cmd_scan_dev(int argc, char **argv)
}
if(argc<=devstart){
-
int ret;
printf("Scanning for Btrfs filesystems\n");
diff --git a/utils.h b/utils.h
index c5f55e1..5a0b9e9 100644
--- a/utils.h
+++ b/utils.h
@@ -39,6 +39,7 @@ int btrfs_scan_one_dir(char *dirname, int run_ioctl);
int check_mounted(const char *devicename);
int check_mounted_where(int fd, const char *file, char *where, int size,
struct btrfs_fs_devices **fs_devices_mnt);
+int blk_file_in_dev_list(struct btrfs_fs_devices *fs_devices, const char
*file);
int btrfs_device_already_in_root(struct btrfs_root *root, int fd,
int super_offset);
char *pretty_sizes(u64 size);
--
1.7.6.5
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Josef Bacik
2012-May-31 14:31 UTC
Re: [PATCH] Btrfs-progs: Update mtab if necessary when device was deleted in btrfs
On Thu, May 31, 2012 at 06:28:31PM +0800, Miao Xie wrote:> Now if we remove the device that is specified when mounting, btrfs will update > the mount information in /proc, such as the information in /proc/mounts. So > in order to guarantee the consistency between /etc/mtab and the mount > information in /proc, we must update /etc/mtab. This patch does it. > > This patch need libmount and libmount-devel(version >= 2.19) packages to > compile. >Does this work well with say Fedora where /etc/mtab is just a symlink to /proc/mounts? 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
Miao Xie
2012-Jun-01 01:41 UTC
Re: [PATCH] Btrfs-progs: Update mtab if necessary when device was deleted in btrfs
On Thu, 31 May 2012 10:31:48 -0400, Josef Bacik wrote:> On Thu, May 31, 2012 at 06:28:31PM +0800, Miao Xie wrote: >> Now if we remove the device that is specified when mounting, btrfs will update >> the mount information in /proc, such as the information in /proc/mounts. So >> in order to guarantee the consistency between /etc/mtab and the mount >> information in /proc, we must update /etc/mtab. This patch does it. >> >> This patch need libmount and libmount-devel(version >= 2.19) packages to >> compile. >> > > Does this work well with say Fedora where /etc/mtab is just a symlink to > /proc/mounts? Thanks,Yes, if /etc/mtab is not a regular file, we will skip the update. And I have do some test for it and all of them passed. This patch can not work well on your machine? Thanks Miao -- 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
Josef Bacik
2012-Jun-01 12:46 UTC
Re: [PATCH] Btrfs-progs: Update mtab if necessary when device was deleted in btrfs
On Fri, Jun 01, 2012 at 09:41:46AM +0800, Miao Xie wrote:> On Thu, 31 May 2012 10:31:48 -0400, Josef Bacik wrote: > > On Thu, May 31, 2012 at 06:28:31PM +0800, Miao Xie wrote: > >> Now if we remove the device that is specified when mounting, btrfs will update > >> the mount information in /proc, such as the information in /proc/mounts. So > >> in order to guarantee the consistency between /etc/mtab and the mount > >> information in /proc, we must update /etc/mtab. This patch does it. > >> > >> This patch need libmount and libmount-devel(version >= 2.19) packages to > >> compile. > >> > > > > Does this work well with say Fedora where /etc/mtab is just a symlink to > > /proc/mounts? Thanks, > > Yes, if /etc/mtab is not a regular file, we will skip the update. And I have > do some test for it and all of them passed. > > This patch can not work well on your machine? >It didn''t but I think I screwed something up so ignore me. 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