/*
* used by btrfsctl to scan devices when no FS is mounted
*/
static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
struct btrfs_ioctl_vol_args *vol;
struct btrfs_fs_devices *fs_devices;
int ret = -ENOTTY;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
vol = kmalloc(sizeof(*vol), GFP_KERNEL);
if (!vol)
return -ENOMEM;
if (copy_from_user(vol, (void __user *)arg, sizeof(*vol))) {
ret = -EFAULT;
goto out;
}
switch (cmd) {
case BTRFS_IOC_SCAN_DEV:
ret = btrfs_scan_one_device(vol->name, FMODE_READ,
&btrfs_fs_type, &fs_devices);
break;
}
out:
kfree(vol);
return ret;
}
/*
* Parse mount options that are required early in the mount process.
*
* All other options will be parsed on much later in the mount process and
* only when we need to allocate a new super block.
*/
static int btrfs_parse_early_options(const char *options, fmode_t flags,
void *holder, char **subvol_name,
struct btrfs_fs_devices **fs_devices)
{
substring_t args[MAX_OPT_ARGS];
char *opts, *p;
int error = 0;
if (!options)
goto out;
/*
* strsep changes the string, duplicate it because parse_options
* gets called twice
*/
opts = kstrdup(options, GFP_KERNEL);
if (!opts)
return -ENOMEM;
while ((p = strsep(&opts, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_subvol:
*subvol_name = match_strdup(&args[0]);
break;
case Opt_device:
error = btrfs_scan_one_device(match_strdup(&args[0]),
flags, holder, fs_devices);
if (error)
goto out_free_opts;
break;
default:
break;
}
}
out_free_opts:
kfree(opts);
out:
/*
* If no subvolume name is specified we use the default one. Allocate
* a copy of the string "." here so that code later in the
* mount path doesn't care if it's the default volume or another one.
*/
if (!*subvol_name) {
*subvol_name = kstrdup(".", GFP_KERNEL);
if (!*subvol_name)
return -ENOMEM;
}
return error;
}
static struct btrfs_fs_info *__open_ctree_fd(int fp, const char *path,
u64 sb_bytenr,
u64 root_tree_bytenr, int writes,
int partial)
{
u32 sectorsize;
u32 nodesize;
u32 leafsize;
u32 blocksize;
u32 stripesize;
u64 generation;
struct btrfs_key key;
struct btrfs_root *tree_root = malloc(sizeof(struct btrfs_root));
struct btrfs_root *extent_root = malloc(sizeof(struct btrfs_root));
struct btrfs_root *chunk_root = malloc(sizeof(struct btrfs_root));
struct btrfs_root *dev_root = malloc(sizeof(struct btrfs_root));
struct btrfs_root *csum_root = malloc(sizeof(struct btrfs_root));
struct btrfs_fs_info *fs_info = malloc(sizeof(*fs_info));
int ret;
struct btrfs_super_block *disk_super;
struct btrfs_fs_devices *fs_devices = NULL;
u64 total_devs;
u64 features;
if (sb_bytenr == 0)
sb_bytenr = BTRFS_SUPER_INFO_OFFSET;
/* try to drop all the caches */
if (posix_fadvise(fp, 0, 0, POSIX_FADV_DONTNEED))
fprintf(stderr, "Warning, could not drop caches\n");
ret = btrfs_scan_one_device(fp, path, &fs_devices,
&total_devs, sb_bytenr);
if (ret) {
fprintf(stderr, "No valid Btrfs found on %s\n", path);
goto out;
}
if (total_devs != 1) {
ret = btrfs_scan_for_fsid(fs_devices, total_devs, 1);
if (ret)
goto out;
}
memset(fs_info, 0, sizeof(*fs_info));
fs_info->super_copy = calloc(1, BTRFS_SUPER_INFO_SIZE);
fs_info->tree_root = tree_root;
fs_info->extent_root = extent_root;
fs_info->chunk_root = chunk_root;
fs_info->dev_root = dev_root;
fs_info->csum_root = csum_root;
if (!writes)
fs_info->readonly = 1;
extent_io_tree_init(&fs_info->extent_cache);
extent_io_tree_init(&fs_info->free_space_cache);
extent_io_tree_init(&fs_info->block_group_cache);
extent_io_tree_init(&fs_info->pinned_extents);
extent_io_tree_init(&fs_info->pending_del);
extent_io_tree_init(&fs_info->extent_ins);
cache_tree_init(&fs_info->fs_root_cache);
cache_tree_init(&fs_info->mapping_tree.cache_tree);
mutex_init(&fs_info->fs_mutex);
fs_info->fs_devices = fs_devices;
INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
INIT_LIST_HEAD(&fs_info->space_info);
__setup_root(4096, 4096, 4096, 4096, tree_root,
fs_info, BTRFS_ROOT_TREE_OBJECTID);
if (writes)
ret = btrfs_open_devices(fs_devices, O_RDWR);
else
ret = btrfs_open_devices(fs_devices, O_RDONLY);
if (ret)
goto out_cleanup;
fs_info->super_bytenr = sb_bytenr;
disk_super = fs_info->super_copy;
ret = btrfs_read_dev_super(fs_devices->latest_bdev,
disk_super, sb_bytenr);
if (ret) {
printk("No valid btrfs found\n");
goto out_devices;
}
memcpy(fs_info->fsid, &disk_super->fsid, BTRFS_FSID_SIZE);
features = btrfs_super_incompat_flags(disk_super) &
~BTRFS_FEATURE_INCOMPAT_SUPP;
if (features) {
printk("couldn't open because of unsupported "
"option features (%Lx).\n",
(unsigned long long)features);
goto out_devices;
}
features = btrfs_super_incompat_flags(disk_super);
if (!(features & BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF)) {
features |= BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF;
btrfs_set_super_incompat_flags(disk_super, features);
}
features = btrfs_super_compat_ro_flags(disk_super) &
~BTRFS_FEATURE_COMPAT_RO_SUPP;
if (writes && features) {
printk("couldn't open RDWR because of unsupported "
"option features (%Lx).\n",
(unsigned long long)features);
goto out_devices;
}
nodesize = btrfs_super_nodesize(disk_super);
leafsize = btrfs_super_leafsize(disk_super);
sectorsize = btrfs_super_sectorsize(disk_super);
stripesize = btrfs_super_stripesize(disk_super);
tree_root->nodesize = nodesize;
tree_root->leafsize = leafsize;
tree_root->sectorsize = sectorsize;
tree_root->stripesize = stripesize;
ret = btrfs_read_sys_array(tree_root);
if (ret)
goto out_devices;
blocksize = btrfs_level_size(tree_root,
btrfs_super_chunk_root_level(disk_super));
generation = btrfs_super_chunk_root_generation(disk_super);
__setup_root(nodesize, leafsize, sectorsize, stripesize,
chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
chunk_root->node = read_tree_block(chunk_root,
btrfs_super_chunk_root(disk_super),
blocksize, generation);
if (!extent_buffer_uptodate(chunk_root->node)) {
printk("Couldn't read chunk root\n");
goto out_devices;
}
read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
(unsigned long)btrfs_header_chunk_tree_uuid(chunk_root->node),
BTRFS_UUID_SIZE);
if (!(btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_METADUMP)) {
ret = btrfs_read_chunk_tree(chunk_root);
if (ret) {
printk("Couldn't read chunk tree\n");
goto out_chunk;
}
}
blocksize = btrfs_level_size(tree_root,
btrfs_super_root_level(disk_super));
generation = btrfs_super_generation(disk_super);
if (!root_tree_bytenr)
root_tree_bytenr = btrfs_super_root(disk_super);
tree_root->node = read_tree_block(tree_root,
root_tree_bytenr,
blocksize, generation);
if (!extent_buffer_uptodate(tree_root->node)) {
printk("Couldn't read tree root\n");
goto out_failed;
}
ret = find_and_setup_root(tree_root, fs_info,
BTRFS_EXTENT_TREE_OBJECTID, extent_root);
if (ret) {
printk("Couldn't setup extent tree\n");
goto out_failed;
}
extent_root->track_dirty = 1;
ret = find_and_setup_root(tree_root, fs_info,
BTRFS_DEV_TREE_OBJECTID, dev_root);
if (ret) {
printk("Couldn't setup device tree\n");
goto out_failed;
}
dev_root->track_dirty = 1;
ret = find_and_setup_root(tree_root, fs_info,
BTRFS_CSUM_TREE_OBJECTID, csum_root);
if (ret) {
printk("Couldn't setup csum tree\n");
if (!partial)
goto out_failed;
}
csum_root->track_dirty = 1;
find_and_setup_log_root(tree_root, fs_info, disk_super);
fs_info->generation = generation;
fs_info->last_trans_committed = generation;
btrfs_read_block_groups(fs_info->tree_root);
key.objectid = BTRFS_FS_TREE_OBJECTID;
key.type = BTRFS_ROOT_ITEM_KEY;
key.offset = (u64)-1;
fs_info->fs_root = btrfs_read_fs_root(fs_info, &key);
if (!fs_info->fs_root)
goto out_failed;
fs_info->data_alloc_profile = (u64)-1;
fs_info->metadata_alloc_profile = (u64)-1;
fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
return fs_info;
out_failed:
if (partial)
return fs_info;
if (fs_info->csum_root)
free_extent_buffer(fs_info->csum_root->node);
if (fs_info->dev_root)
free_extent_buffer(fs_info->dev_root->node);
if (fs_info->extent_root)
free_extent_buffer(fs_info->extent_root->node);
if (fs_info->tree_root)
free_extent_buffer(fs_info->tree_root->node);
out_chunk:
if (fs_info->chunk_root)
free_extent_buffer(fs_info->chunk_root->node);
out_devices:
close_all_devices(fs_info);
out_cleanup:
extent_io_tree_cleanup(&fs_info->extent_cache);
extent_io_tree_cleanup(&fs_info->free_space_cache);
extent_io_tree_cleanup(&fs_info->block_group_cache);
extent_io_tree_cleanup(&fs_info->pinned_extents);
extent_io_tree_cleanup(&fs_info->pending_del);
extent_io_tree_cleanup(&fs_info->extent_ins);
out:
free(tree_root);
free(extent_root);
free(chunk_root);
free(dev_root);
free(csum_root);
free(fs_info);
return NULL;
}
int btrfs_scan_one_dir(char *dirname, int run_ioctl)
{
DIR *dirp = NULL;
struct dirent *dirent;
struct pending_dir *pending;
struct stat st;
int ret;
int fd;
int dirname_len;
int pathlen;
char *fullpath;
struct list_head pending_list;
struct btrfs_fs_devices *tmp_devices;
u64 num_devices;
INIT_LIST_HEAD(&pending_list);
pending = malloc(sizeof(*pending));
if (!pending)
return -ENOMEM;
strcpy(pending->name, dirname);
again:
dirname_len = strlen(pending->name);
pathlen = 1024;
fullpath = malloc(pathlen);
dirname = pending->name;
if (!fullpath) {
ret = -ENOMEM;
goto fail;
}
dirp = opendir(dirname);
if (!dirp) {
fprintf(stderr, "Unable to open /sys/block for scanning\n");
return -ENOENT;
}
while(1) {
dirent = readdir(dirp);
if (!dirent)
break;
if (dirent->d_name[0] == '.')
continue;
if (dirname_len + strlen(dirent->d_name) + 2 > pathlen) {
ret = -EFAULT;
goto fail;
}
snprintf(fullpath, pathlen, "%s/%s", dirname, dirent->d_name);
ret = lstat(fullpath, &st);
if (ret < 0) {
fprintf(stderr, "failed to stat %s\n", fullpath);
continue;
}
if (S_ISLNK(st.st_mode))
continue;
if (S_ISDIR(st.st_mode)) {
struct pending_dir *next = malloc(sizeof(*next));
if (!next) {
ret = -ENOMEM;
goto fail;
}
strcpy(next->name, fullpath);
list_add_tail(&next->list, &pending_list);
}
if (!S_ISBLK(st.st_mode)) {
continue;
}
fd = open(fullpath, O_RDONLY);
if (fd < 0) {
fprintf(stderr, "failed to read %s\n", fullpath);
continue;
}
ret = btrfs_scan_one_device(fd, fullpath, &tmp_devices,
&num_devices,
BTRFS_SUPER_INFO_OFFSET);
if (ret == 0 && run_ioctl > 0) {
btrfs_register_one_device(fullpath);
}
close(fd);
}
if (!list_empty(&pending_list)) {
free(pending);
pending = list_entry(pending_list.next, struct pending_dir,
list);
list_del(&pending->list);
closedir(dirp);
goto again;
}
static int dev_replace_handle_sigint(int fd)
{
struct sigaction sa = {
.sa_handler = fd == -1 ? SIG_DFL : dev_replace_sigint_handler
};
dev_replace_cancel_fd = fd;
return sigaction(SIGINT, &sa, NULL);
}
static const char *const cmd_start_replace_usage[] = {
"btrfs replace start srcdev|devid targetdev [-Bfr] mount_point",
"Replace device of a btrfs filesystem.",
"On a live filesystem, duplicate the data to the target device which",
"is currently stored on the source device. If the source device is not",
"available anymore, or if the -r option is set, the data is built",
"only using the RAID redundancy mechanisms. After completion of the",
"operation, the source device is removed from the filesystem.",
"If the srcdev is a numerical value, it is assumed to be the device id",
"of the filesystem which is mounted at mount_point, otherwise it is",
"the path to the source device. If the source device is disconnected,",
"from the system, you have to use the devid parameter format.",
"The targetdev needs to be same size or larger than the srcdev.",
"",
"-r only read from srcdev if no other zero-defect mirror exists",
" (enable this if your drive has lots of read errors, the access",
" would be very slow)",
"-f force using and overwriting targetdev even if it looks like",
" containing a valid btrfs filesystem. A valid filesystem is",
" assumed if a btrfs superblock is found which contains a",
" correct checksum. Devices which are currently mounted are",
" never allowed to be used as the targetdev",
"-B do not background",
NULL
};
static int cmd_start_replace(int argc, char **argv)
{
struct btrfs_ioctl_dev_replace_args start_args = {0};
struct btrfs_ioctl_dev_replace_args status_args = {0};
int ret;
int i;
int c;
int fdmnt = -1;
int fdsrcdev = -1;
int fddstdev = -1;
char *path;
char *srcdev;
char *dstdev;
int avoid_reading_from_srcdev = 0;
int force_using_targetdev = 0;
u64 total_devs = 1;
struct btrfs_fs_devices *fs_devices_mnt = NULL;
struct stat st;
u64 dstdev_block_count;
int do_not_background = 0;
int mixed = 0;
while ((c = getopt(argc, argv, "Brf")) != -1) {
switch (c) {
case 'B':
do_not_background = 1;
break;
case 'r':
avoid_reading_from_srcdev = 1;
break;
case 'f':
force_using_targetdev = 1;
break;
case '?':
default:
usage(cmd_start_replace_usage);
}
}
start_args.start.cont_reading_from_srcdev_mode =
avoid_reading_from_srcdev ?
BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_AVOID :
BTRFS_IOCTL_DEV_REPLACE_CONT_READING_FROM_SRCDEV_MODE_ALWAYS;
if (check_argc_exact(argc - optind, 3))
usage(cmd_start_replace_usage);
path = argv[optind + 2];
fdmnt = open_path_or_dev_mnt(path);
if (fdmnt < 0) {
fprintf(stderr, "ERROR: can't access \"%s\": %s\n",
path, strerror(errno));
goto leave_with_error;
}
/* check for possible errors before backgrounding */
status_args.cmd = BTRFS_IOCTL_DEV_REPLACE_CMD_STATUS;
ret = ioctl(fdmnt, BTRFS_IOC_DEV_REPLACE, &status_args);
if (ret) {
fprintf(stderr,
"ERROR: ioctl(DEV_REPLACE_STATUS) failed on \"%s\": %s, %s\n",
path, strerror(errno),
replace_dev_result2string(status_args.result));
goto leave_with_error;
}
if (status_args.result != BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR) {
fprintf(stderr,
"ERROR: ioctl(DEV_REPLACE_STATUS) on \"%s\" returns error: %s\n",
path, replace_dev_result2string(status_args.result));
goto leave_with_error;
}
if (status_args.status.replace_state ==
BTRFS_IOCTL_DEV_REPLACE_STATE_STARTED) {
fprintf(stderr,
"ERROR: btrfs replace on \"%s\" already started!\n",
path);
goto leave_with_error;
}
srcdev = argv[optind];
dstdev = argv[optind + 1];
if (is_numerical(srcdev)) {
struct btrfs_ioctl_fs_info_args fi_args;
struct btrfs_ioctl_dev_info_args *di_args = NULL;
if (atoi(srcdev) == 0) {
fprintf(stderr, "Error: Failed to parse the numerical devid value '%s'\n",
srcdev);
goto leave_with_error;
}
start_args.start.srcdevid = (__u64)atoi(srcdev);
ret = get_fs_info(path, &fi_args, &di_args);
if (ret) {
fprintf(stderr, "ERROR: getting dev info for devstats failed: "
"%s\n", strerror(-ret));
free(di_args);
goto leave_with_error;
}
if (!fi_args.num_devices) {
fprintf(stderr, "ERROR: no devices found\n");
free(di_args);
goto leave_with_error;
}
for (i = 0; i < fi_args.num_devices; i++)
if (start_args.start.srcdevid == di_args[i].devid)
break;
free(di_args);
if (i == fi_args.num_devices) {
fprintf(stderr, "Error: '%s' is not a valid devid for filesystem '%s'\n",
srcdev, path);
goto leave_with_error;
}
} else {
fdsrcdev = open(srcdev, O_RDWR);
if (fdsrcdev < 0) {
fprintf(stderr, "Error: Unable to open device '%s'\n",
srcdev);
goto leave_with_error;
}
ret = fstat(fdsrcdev, &st);
if (ret) {
fprintf(stderr, "Error: Unable to stat '%s'\n", srcdev);
goto leave_with_error;
}
if (!S_ISBLK(st.st_mode)) {
fprintf(stderr, "Error: '%s' is not a block device\n",
srcdev);
goto leave_with_error;
}
strncpy((char *)start_args.start.srcdev_name, srcdev,
BTRFS_DEVICE_PATH_NAME_MAX);
close(fdsrcdev);
fdsrcdev = -1;
start_args.start.srcdevid = 0;
}
ret = check_mounted(dstdev);
if (ret < 0) {
fprintf(stderr, "Error checking %s mount status\n", dstdev);
goto leave_with_error;
}
if (ret == 1) {
fprintf(stderr,
"Error, target device %s is in use and currently mounted!\n",
dstdev);
goto leave_with_error;
}
fddstdev = open(dstdev, O_RDWR);
if (fddstdev < 0) {
fprintf(stderr, "Unable to open %s\n", dstdev);
goto leave_with_error;
}
ret = btrfs_scan_one_device(fddstdev, dstdev, &fs_devices_mnt,
&total_devs, BTRFS_SUPER_INFO_OFFSET);
if (ret >= 0 && !force_using_targetdev) {
fprintf(stderr,
"Error, target device %s contains filesystem, use '-f' to force overwriting.\n",
dstdev);
goto leave_with_error;
}
ret = fstat(fddstdev, &st);
if (ret) {
fprintf(stderr, "Error: Unable to stat '%s'\n", dstdev);
goto leave_with_error;
}
if (!S_ISBLK(st.st_mode)) {
fprintf(stderr, "Error: '%s' is not a block device\n", dstdev);
goto leave_with_error;
}
strncpy((char *)start_args.start.tgtdev_name, dstdev,
BTRFS_DEVICE_PATH_NAME_MAX);
if (btrfs_prepare_device(fddstdev, dstdev, 1, &dstdev_block_count, 0,
&mixed, 0)) {
fprintf(stderr, "Error: Failed to prepare device '%s'\n",
dstdev);
goto leave_with_error;
}
close(fddstdev);
fddstdev = -1;
dev_replace_handle_sigint(fdmnt);
if (!do_not_background) {
if (daemon(0, 0) < 0) {
fprintf(stderr, "ERROR, backgrounding failed: %s\n",
strerror(errno));
goto leave_with_error;
}
}
start_args.cmd = BTRFS_IOCTL_DEV_REPLACE_CMD_START;
ret = ioctl(fdmnt, BTRFS_IOC_DEV_REPLACE, &start_args);
if (do_not_background) {
if (ret) {
fprintf(stderr,
"ERROR: ioctl(DEV_REPLACE_START) failed on \"%s\": %s, %s\n",
path, strerror(errno),
replace_dev_result2string(start_args.result));
goto leave_with_error;
}
if (start_args.result !=
BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR) {
fprintf(stderr,
"ERROR: ioctl(DEV_REPLACE_START) on \"%s\" returns error: %s\n",
path,
replace_dev_result2string(start_args.result));
goto leave_with_error;
}
}
close(fdmnt);
return 0;
leave_with_error:
if (fdmnt != -1)
close(fdmnt);
if (fdsrcdev != -1)
close(fdsrcdev);
if (fddstdev != -1)
close(fddstdev);
return -1;
}
static const char *const cmd_status_replace_usage[] = {
"btrfs replace status mount_point [-1]",
"Print status and progress information of a running device replace",
"operation",
"",
"-1 print once instead of print continously until the replace",
" operation finishes (or is canceled)",
NULL
};
static int cmd_status_replace(int argc, char **argv)
{
int fd;
int e;
int c;
char *path;
int once = 0;
int ret;
while ((c = getopt(argc, argv, "1")) != -1) {
switch (c) {
case '1':
once = 1;
break;
case '?':
default:
usage(cmd_status_replace_usage);
}
}
if (check_argc_exact(argc - optind, 1))
usage(cmd_status_replace_usage);
path = argv[optind];
fd = open_file_or_dir(path);
e = errno;
if (fd < 0) {
fprintf(stderr, "ERROR: can't access \"%s\": %s\n",
path, strerror(e));
return -1;
}
ret = print_replace_status(fd, path, once);
close(fd);
return ret;
}
/*
* Find a superblock for the given device / mount point.
*
* Note: This is based on get_sb_bdev from fs/super.c with a few additions
* for multiple device setup. Make sure to keep it in sync.
*/
static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data, struct vfsmount *mnt)
{
char *subvol_name = NULL;
struct block_device *bdev = NULL;
struct super_block *s;
struct dentry *root;
struct btrfs_fs_devices *fs_devices = NULL;
fmode_t mode = FMODE_READ;
int error = 0;
if (!(flags & MS_RDONLY))
mode |= FMODE_WRITE;
error = btrfs_parse_early_options(data, mode, fs_type,
&subvol_name, &fs_devices);
if (error)
return error;
error = btrfs_scan_one_device(dev_name, mode, fs_type, &fs_devices);
if (error)
goto error_free_subvol_name;
error = btrfs_open_devices(fs_devices, mode, fs_type);
if (error)
goto error_free_subvol_name;
if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
error = -EACCES;
goto error_close_devices;
}
bdev = fs_devices->latest_bdev;
s = sget(fs_type, btrfs_test_super, set_anon_super, fs_devices);
if (IS_ERR(s))
goto error_s;
if (s->s_root) {
if ((flags ^ s->s_flags) & MS_RDONLY) {
up_write(&s->s_umount);
deactivate_super(s);
error = -EBUSY;
goto error_close_devices;
}
btrfs_close_devices(fs_devices);
} else {
char b[BDEVNAME_SIZE];
s->s_flags = flags;
strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
error = btrfs_fill_super(s, fs_devices, data,
flags & MS_SILENT ? 1 : 0);
if (error) {
up_write(&s->s_umount);
deactivate_super(s);
goto error_free_subvol_name;
}
btrfs_sb(s)->fs_info->bdev_holder = fs_type;
s->s_flags |= MS_ACTIVE;
}
if (!strcmp(subvol_name, "."))
root = dget(s->s_root);
else {
mutex_lock(&s->s_root->d_inode->i_mutex);
root = lookup_one_len(subvol_name, s->s_root,
strlen(subvol_name));
mutex_unlock(&s->s_root->d_inode->i_mutex);
if (IS_ERR(root)) {
up_write(&s->s_umount);
deactivate_super(s);
error = PTR_ERR(root);
goto error_free_subvol_name;
}
if (!root->d_inode) {
dput(root);
up_write(&s->s_umount);
deactivate_super(s);
error = -ENXIO;
goto error_free_subvol_name;
}
}
mnt->mnt_sb = s;
mnt->mnt_root = root;
kfree(subvol_name);
return 0;
error_s:
error = PTR_ERR(s);
error_close_devices:
btrfs_close_devices(fs_devices);
error_free_subvol_name:
kfree(subvol_name);
return error;
}
