linux/fs/btrfs/super.c
Linus Torvalds 795d580bae Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
  Btrfs: add check for changed leaves in setup_leaf_for_split
  Btrfs: create snapshot references in same commit as snapshot
  Btrfs: fix small race with delalloc flushing waitqueue's
  Btrfs: use add_to_page_cache_lru, use __page_cache_alloc
  Btrfs: fix chunk allocate size calculation
  Btrfs: kill max_extent mount option
  Btrfs: fail to mount if we have problems reading the block groups
  Btrfs: check btrfs_get_extent return for IS_ERR()
  Btrfs: handle kmalloc() failure in inode lookup ioctl
  Btrfs: dereferencing freed memory
  Btrfs: Simplify num_stripes's calculation logical for __btrfs_alloc_chunk()
  Btrfs: Add error handle for btrfs_search_slot() in btrfs_read_chunk_tree()
  Btrfs: Remove unnecessary finish_wait() in wait_current_trans()
  Btrfs: add NULL check for do_walk_down()
  Btrfs: remove duplicate include in ioctl.c

Fix trivial conflict in fs/btrfs/compression.c due to slab.h include
cleanups.
2010-04-05 13:21:15 -07:00

911 lines
22 KiB
C

/*
* Copyright (C) 2007 Oracle. 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.
*/
#include <linux/blkdev.h>
#include <linux/module.h>
#include <linux/buffer_head.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <linux/backing-dev.h>
#include <linux/mount.h>
#include <linux/mpage.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/statfs.h>
#include <linux/compat.h>
#include <linux/parser.h>
#include <linux/ctype.h>
#include <linux/namei.h>
#include <linux/miscdevice.h>
#include <linux/magic.h>
#include <linux/slab.h>
#include "compat.h"
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "btrfs_inode.h"
#include "ioctl.h"
#include "print-tree.h"
#include "xattr.h"
#include "volumes.h"
#include "version.h"
#include "export.h"
#include "compression.h"
static const struct super_operations btrfs_super_ops;
static void btrfs_put_super(struct super_block *sb)
{
struct btrfs_root *root = btrfs_sb(sb);
int ret;
ret = close_ctree(root);
sb->s_fs_info = NULL;
}
enum {
Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum,
Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd,
Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress,
Opt_compress_force, Opt_notreelog, Opt_ratio, Opt_flushoncommit,
Opt_discard, Opt_err,
};
static match_table_t tokens = {
{Opt_degraded, "degraded"},
{Opt_subvol, "subvol=%s"},
{Opt_subvolid, "subvolid=%d"},
{Opt_device, "device=%s"},
{Opt_nodatasum, "nodatasum"},
{Opt_nodatacow, "nodatacow"},
{Opt_nobarrier, "nobarrier"},
{Opt_max_inline, "max_inline=%s"},
{Opt_alloc_start, "alloc_start=%s"},
{Opt_thread_pool, "thread_pool=%d"},
{Opt_compress, "compress"},
{Opt_compress_force, "compress-force"},
{Opt_ssd, "ssd"},
{Opt_ssd_spread, "ssd_spread"},
{Opt_nossd, "nossd"},
{Opt_noacl, "noacl"},
{Opt_notreelog, "notreelog"},
{Opt_flushoncommit, "flushoncommit"},
{Opt_ratio, "metadata_ratio=%d"},
{Opt_discard, "discard"},
{Opt_err, NULL},
};
/*
* Regular mount options parser. Everything that is needed only when
* reading in a new superblock is parsed here.
*/
int btrfs_parse_options(struct btrfs_root *root, char *options)
{
struct btrfs_fs_info *info = root->fs_info;
substring_t args[MAX_OPT_ARGS];
char *p, *num, *orig;
int intarg;
int ret = 0;
if (!options)
return 0;
/*
* strsep changes the string, duplicate it because parse_options
* gets called twice
*/
options = kstrdup(options, GFP_NOFS);
if (!options)
return -ENOMEM;
orig = options;
while ((p = strsep(&options, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_degraded:
printk(KERN_INFO "btrfs: allowing degraded mounts\n");
btrfs_set_opt(info->mount_opt, DEGRADED);
break;
case Opt_subvol:
case Opt_subvolid:
case Opt_device:
/*
* These are parsed by btrfs_parse_early_options
* and can be happily ignored here.
*/
break;
case Opt_nodatasum:
printk(KERN_INFO "btrfs: setting nodatasum\n");
btrfs_set_opt(info->mount_opt, NODATASUM);
break;
case Opt_nodatacow:
printk(KERN_INFO "btrfs: setting nodatacow\n");
btrfs_set_opt(info->mount_opt, NODATACOW);
btrfs_set_opt(info->mount_opt, NODATASUM);
break;
case Opt_compress:
printk(KERN_INFO "btrfs: use compression\n");
btrfs_set_opt(info->mount_opt, COMPRESS);
break;
case Opt_compress_force:
printk(KERN_INFO "btrfs: forcing compression\n");
btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
btrfs_set_opt(info->mount_opt, COMPRESS);
break;
case Opt_ssd:
printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
btrfs_set_opt(info->mount_opt, SSD);
break;
case Opt_ssd_spread:
printk(KERN_INFO "btrfs: use spread ssd "
"allocation scheme\n");
btrfs_set_opt(info->mount_opt, SSD);
btrfs_set_opt(info->mount_opt, SSD_SPREAD);
break;
case Opt_nossd:
printk(KERN_INFO "btrfs: not using ssd allocation "
"scheme\n");
btrfs_set_opt(info->mount_opt, NOSSD);
btrfs_clear_opt(info->mount_opt, SSD);
btrfs_clear_opt(info->mount_opt, SSD_SPREAD);
break;
case Opt_nobarrier:
printk(KERN_INFO "btrfs: turning off barriers\n");
btrfs_set_opt(info->mount_opt, NOBARRIER);
break;
case Opt_thread_pool:
intarg = 0;
match_int(&args[0], &intarg);
if (intarg) {
info->thread_pool_size = intarg;
printk(KERN_INFO "btrfs: thread pool %d\n",
info->thread_pool_size);
}
break;
case Opt_max_inline:
num = match_strdup(&args[0]);
if (num) {
info->max_inline = memparse(num, NULL);
kfree(num);
if (info->max_inline) {
info->max_inline = max_t(u64,
info->max_inline,
root->sectorsize);
}
printk(KERN_INFO "btrfs: max_inline at %llu\n",
(unsigned long long)info->max_inline);
}
break;
case Opt_alloc_start:
num = match_strdup(&args[0]);
if (num) {
info->alloc_start = memparse(num, NULL);
kfree(num);
printk(KERN_INFO
"btrfs: allocations start at %llu\n",
(unsigned long long)info->alloc_start);
}
break;
case Opt_noacl:
root->fs_info->sb->s_flags &= ~MS_POSIXACL;
break;
case Opt_notreelog:
printk(KERN_INFO "btrfs: disabling tree log\n");
btrfs_set_opt(info->mount_opt, NOTREELOG);
break;
case Opt_flushoncommit:
printk(KERN_INFO "btrfs: turning on flush-on-commit\n");
btrfs_set_opt(info->mount_opt, FLUSHONCOMMIT);
break;
case Opt_ratio:
intarg = 0;
match_int(&args[0], &intarg);
if (intarg) {
info->metadata_ratio = intarg;
printk(KERN_INFO "btrfs: metadata ratio %d\n",
info->metadata_ratio);
}
break;
case Opt_discard:
btrfs_set_opt(info->mount_opt, DISCARD);
break;
case Opt_err:
printk(KERN_INFO "btrfs: unrecognized mount option "
"'%s'\n", p);
ret = -EINVAL;
goto out;
default:
break;
}
}
out:
kfree(orig);
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, u64 *subvol_objectid,
struct btrfs_fs_devices **fs_devices)
{
substring_t args[MAX_OPT_ARGS];
char *opts, *p;
int error = 0;
int intarg;
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_subvolid:
intarg = 0;
error = match_int(&args[0], &intarg);
if (!error) {
/* we want the original fs_tree */
if (!intarg)
*subvol_objectid =
BTRFS_FS_TREE_OBJECTID;
else
*subvol_objectid = intarg;
}
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 dentry *get_default_root(struct super_block *sb,
u64 subvol_objectid)
{
struct btrfs_root *root = sb->s_fs_info;
struct btrfs_root *new_root;
struct btrfs_dir_item *di;
struct btrfs_path *path;
struct btrfs_key location;
struct inode *inode;
struct dentry *dentry;
u64 dir_id;
int new = 0;
/*
* We have a specific subvol we want to mount, just setup location and
* go look up the root.
*/
if (subvol_objectid) {
location.objectid = subvol_objectid;
location.type = BTRFS_ROOT_ITEM_KEY;
location.offset = (u64)-1;
goto find_root;
}
path = btrfs_alloc_path();
if (!path)
return ERR_PTR(-ENOMEM);
path->leave_spinning = 1;
/*
* Find the "default" dir item which points to the root item that we
* will mount by default if we haven't been given a specific subvolume
* to mount.
*/
dir_id = btrfs_super_root_dir(&root->fs_info->super_copy);
di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
if (!di) {
/*
* Ok the default dir item isn't there. This is weird since
* it's always been there, but don't freak out, just try and
* mount to root most subvolume.
*/
btrfs_free_path(path);
dir_id = BTRFS_FIRST_FREE_OBJECTID;
new_root = root->fs_info->fs_root;
goto setup_root;
}
btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
btrfs_free_path(path);
find_root:
new_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
if (IS_ERR(new_root))
return ERR_PTR(PTR_ERR(new_root));
if (btrfs_root_refs(&new_root->root_item) == 0)
return ERR_PTR(-ENOENT);
dir_id = btrfs_root_dirid(&new_root->root_item);
setup_root:
location.objectid = dir_id;
location.type = BTRFS_INODE_ITEM_KEY;
location.offset = 0;
inode = btrfs_iget(sb, &location, new_root, &new);
if (!inode)
return ERR_PTR(-ENOMEM);
/*
* If we're just mounting the root most subvol put the inode and return
* a reference to the dentry. We will have already gotten a reference
* to the inode in btrfs_fill_super so we're good to go.
*/
if (!new && sb->s_root->d_inode == inode) {
iput(inode);
return dget(sb->s_root);
}
if (new) {
const struct qstr name = { .name = "/", .len = 1 };
/*
* New inode, we need to make the dentry a sibling of s_root so
* everything gets cleaned up properly on unmount.
*/
dentry = d_alloc(sb->s_root, &name);
if (!dentry) {
iput(inode);
return ERR_PTR(-ENOMEM);
}
d_splice_alias(inode, dentry);
} else {
/*
* We found the inode in cache, just find a dentry for it and
* put the reference to the inode we just got.
*/
dentry = d_find_alias(inode);
iput(inode);
}
return dentry;
}
static int btrfs_fill_super(struct super_block *sb,
struct btrfs_fs_devices *fs_devices,
void *data, int silent)
{
struct inode *inode;
struct dentry *root_dentry;
struct btrfs_super_block *disk_super;
struct btrfs_root *tree_root;
struct btrfs_key key;
int err;
sb->s_maxbytes = MAX_LFS_FILESIZE;
sb->s_magic = BTRFS_SUPER_MAGIC;
sb->s_op = &btrfs_super_ops;
sb->s_export_op = &btrfs_export_ops;
sb->s_xattr = btrfs_xattr_handlers;
sb->s_time_gran = 1;
#ifdef CONFIG_BTRFS_FS_POSIX_ACL
sb->s_flags |= MS_POSIXACL;
#endif
tree_root = open_ctree(sb, fs_devices, (char *)data);
if (IS_ERR(tree_root)) {
printk("btrfs: open_ctree failed\n");
return PTR_ERR(tree_root);
}
sb->s_fs_info = tree_root;
disk_super = &tree_root->fs_info->super_copy;
key.objectid = BTRFS_FIRST_FREE_OBJECTID;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root, NULL);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
goto fail_close;
}
root_dentry = d_alloc_root(inode);
if (!root_dentry) {
iput(inode);
err = -ENOMEM;
goto fail_close;
}
sb->s_root = root_dentry;
save_mount_options(sb, data);
return 0;
fail_close:
close_ctree(tree_root);
return err;
}
int btrfs_sync_fs(struct super_block *sb, int wait)
{
struct btrfs_trans_handle *trans;
struct btrfs_root *root = btrfs_sb(sb);
int ret;
if (!wait) {
filemap_flush(root->fs_info->btree_inode->i_mapping);
return 0;
}
btrfs_start_delalloc_inodes(root, 0);
btrfs_wait_ordered_extents(root, 0, 0);
trans = btrfs_start_transaction(root, 1);
ret = btrfs_commit_transaction(trans, root);
return ret;
}
static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
{
struct btrfs_root *root = btrfs_sb(vfs->mnt_sb);
struct btrfs_fs_info *info = root->fs_info;
if (btrfs_test_opt(root, DEGRADED))
seq_puts(seq, ",degraded");
if (btrfs_test_opt(root, NODATASUM))
seq_puts(seq, ",nodatasum");
if (btrfs_test_opt(root, NODATACOW))
seq_puts(seq, ",nodatacow");
if (btrfs_test_opt(root, NOBARRIER))
seq_puts(seq, ",nobarrier");
if (info->max_inline != 8192 * 1024)
seq_printf(seq, ",max_inline=%llu",
(unsigned long long)info->max_inline);
if (info->alloc_start != 0)
seq_printf(seq, ",alloc_start=%llu",
(unsigned long long)info->alloc_start);
if (info->thread_pool_size != min_t(unsigned long,
num_online_cpus() + 2, 8))
seq_printf(seq, ",thread_pool=%d", info->thread_pool_size);
if (btrfs_test_opt(root, COMPRESS))
seq_puts(seq, ",compress");
if (btrfs_test_opt(root, NOSSD))
seq_puts(seq, ",nossd");
if (btrfs_test_opt(root, SSD_SPREAD))
seq_puts(seq, ",ssd_spread");
else if (btrfs_test_opt(root, SSD))
seq_puts(seq, ",ssd");
if (btrfs_test_opt(root, NOTREELOG))
seq_puts(seq, ",notreelog");
if (btrfs_test_opt(root, FLUSHONCOMMIT))
seq_puts(seq, ",flushoncommit");
if (btrfs_test_opt(root, DISCARD))
seq_puts(seq, ",discard");
if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
seq_puts(seq, ",noacl");
return 0;
}
static int btrfs_test_super(struct super_block *s, void *data)
{
struct btrfs_fs_devices *test_fs_devices = data;
struct btrfs_root *root = btrfs_sb(s);
return root->fs_info->fs_devices == test_fs_devices;
}
/*
* 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)
{
struct block_device *bdev = NULL;
struct super_block *s;
struct dentry *root;
struct btrfs_fs_devices *fs_devices = NULL;
fmode_t mode = FMODE_READ;
char *subvol_name = NULL;
u64 subvol_objectid = 0;
int error = 0;
int found = 0;
if (!(flags & MS_RDONLY))
mode |= FMODE_WRITE;
error = btrfs_parse_early_options(data, mode, fs_type,
&subvol_name, &subvol_objectid,
&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) {
deactivate_locked_super(s);
error = -EBUSY;
goto error_close_devices;
}
found = 1;
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) {
deactivate_locked_super(s);
goto error_free_subvol_name;
}
btrfs_sb(s)->fs_info->bdev_holder = fs_type;
s->s_flags |= MS_ACTIVE;
}
root = get_default_root(s, subvol_objectid);
if (IS_ERR(root)) {
error = PTR_ERR(root);
deactivate_locked_super(s);
goto error;
}
/* if they gave us a subvolume name bind mount into that */
if (strcmp(subvol_name, ".")) {
struct dentry *new_root;
mutex_lock(&root->d_inode->i_mutex);
new_root = lookup_one_len(subvol_name, root,
strlen(subvol_name));
mutex_unlock(&root->d_inode->i_mutex);
if (IS_ERR(new_root)) {
deactivate_locked_super(s);
error = PTR_ERR(new_root);
dput(root);
goto error_close_devices;
}
if (!new_root->d_inode) {
dput(root);
dput(new_root);
deactivate_locked_super(s);
error = -ENXIO;
goto error_close_devices;
}
dput(root);
root = new_root;
}
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);
error:
return error;
}
static int btrfs_remount(struct super_block *sb, int *flags, char *data)
{
struct btrfs_root *root = btrfs_sb(sb);
int ret;
ret = btrfs_parse_options(root, data);
if (ret)
return -EINVAL;
if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
return 0;
if (*flags & MS_RDONLY) {
sb->s_flags |= MS_RDONLY;
ret = btrfs_commit_super(root);
WARN_ON(ret);
} else {
if (root->fs_info->fs_devices->rw_devices == 0)
return -EACCES;
if (btrfs_super_log_root(&root->fs_info->super_copy) != 0)
return -EINVAL;
/* recover relocation */
ret = btrfs_recover_relocation(root);
WARN_ON(ret);
ret = btrfs_cleanup_fs_roots(root->fs_info);
WARN_ON(ret);
sb->s_flags &= ~MS_RDONLY;
}
return 0;
}
static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct btrfs_root *root = btrfs_sb(dentry->d_sb);
struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
struct list_head *head = &root->fs_info->space_info;
struct btrfs_space_info *found;
u64 total_used = 0;
u64 data_used = 0;
int bits = dentry->d_sb->s_blocksize_bits;
__be32 *fsid = (__be32 *)root->fs_info->fsid;
rcu_read_lock();
list_for_each_entry_rcu(found, head, list) {
if (found->flags & (BTRFS_BLOCK_GROUP_DUP|
BTRFS_BLOCK_GROUP_RAID10|
BTRFS_BLOCK_GROUP_RAID1)) {
total_used += found->bytes_used;
if (found->flags & BTRFS_BLOCK_GROUP_DATA)
data_used += found->bytes_used;
else
data_used += found->total_bytes;
}
total_used += found->bytes_used;
if (found->flags & BTRFS_BLOCK_GROUP_DATA)
data_used += found->bytes_used;
else
data_used += found->total_bytes;
}
rcu_read_unlock();
buf->f_namelen = BTRFS_NAME_LEN;
buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
buf->f_bfree = buf->f_blocks - (total_used >> bits);
buf->f_bavail = buf->f_blocks - (data_used >> bits);
buf->f_bsize = dentry->d_sb->s_blocksize;
buf->f_type = BTRFS_SUPER_MAGIC;
/* We treat it as constant endianness (it doesn't matter _which_)
because we want the fsid to come out the same whether mounted
on a big-endian or little-endian host */
buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
/* Mask in the root object ID too, to disambiguate subvols */
buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
return 0;
}
static struct file_system_type btrfs_fs_type = {
.owner = THIS_MODULE,
.name = "btrfs",
.get_sb = btrfs_get_sb,
.kill_sb = kill_anon_super,
.fs_flags = FS_REQUIRES_DEV,
};
/*
* 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 = memdup_user((void __user *)arg, sizeof(*vol));
if (IS_ERR(vol))
return PTR_ERR(vol);
switch (cmd) {
case BTRFS_IOC_SCAN_DEV:
ret = btrfs_scan_one_device(vol->name, FMODE_READ,
&btrfs_fs_type, &fs_devices);
break;
}
kfree(vol);
return ret;
}
static int btrfs_freeze(struct super_block *sb)
{
struct btrfs_root *root = btrfs_sb(sb);
mutex_lock(&root->fs_info->transaction_kthread_mutex);
mutex_lock(&root->fs_info->cleaner_mutex);
return 0;
}
static int btrfs_unfreeze(struct super_block *sb)
{
struct btrfs_root *root = btrfs_sb(sb);
mutex_unlock(&root->fs_info->cleaner_mutex);
mutex_unlock(&root->fs_info->transaction_kthread_mutex);
return 0;
}
static const struct super_operations btrfs_super_ops = {
.drop_inode = btrfs_drop_inode,
.delete_inode = btrfs_delete_inode,
.put_super = btrfs_put_super,
.sync_fs = btrfs_sync_fs,
.show_options = btrfs_show_options,
.write_inode = btrfs_write_inode,
.dirty_inode = btrfs_dirty_inode,
.alloc_inode = btrfs_alloc_inode,
.destroy_inode = btrfs_destroy_inode,
.statfs = btrfs_statfs,
.remount_fs = btrfs_remount,
.freeze_fs = btrfs_freeze,
.unfreeze_fs = btrfs_unfreeze,
};
static const struct file_operations btrfs_ctl_fops = {
.unlocked_ioctl = btrfs_control_ioctl,
.compat_ioctl = btrfs_control_ioctl,
.owner = THIS_MODULE,
};
static struct miscdevice btrfs_misc = {
.minor = MISC_DYNAMIC_MINOR,
.name = "btrfs-control",
.fops = &btrfs_ctl_fops
};
static int btrfs_interface_init(void)
{
return misc_register(&btrfs_misc);
}
static void btrfs_interface_exit(void)
{
if (misc_deregister(&btrfs_misc) < 0)
printk(KERN_INFO "misc_deregister failed for control device");
}
static int __init init_btrfs_fs(void)
{
int err;
err = btrfs_init_sysfs();
if (err)
return err;
err = btrfs_init_cachep();
if (err)
goto free_sysfs;
err = extent_io_init();
if (err)
goto free_cachep;
err = extent_map_init();
if (err)
goto free_extent_io;
err = btrfs_interface_init();
if (err)
goto free_extent_map;
err = register_filesystem(&btrfs_fs_type);
if (err)
goto unregister_ioctl;
printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
return 0;
unregister_ioctl:
btrfs_interface_exit();
free_extent_map:
extent_map_exit();
free_extent_io:
extent_io_exit();
free_cachep:
btrfs_destroy_cachep();
free_sysfs:
btrfs_exit_sysfs();
return err;
}
static void __exit exit_btrfs_fs(void)
{
btrfs_destroy_cachep();
extent_map_exit();
extent_io_exit();
btrfs_interface_exit();
unregister_filesystem(&btrfs_fs_type);
btrfs_exit_sysfs();
btrfs_cleanup_fs_uuids();
btrfs_zlib_exit();
}
module_init(init_btrfs_fs)
module_exit(exit_btrfs_fs)
MODULE_LICENSE("GPL");