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linux/fs/btrfs/super.c
Eric W. Biederman 7f78e03513 fs: Limit sys_mount to only request filesystem modules. 
Modify the request_module to prefix the file system type with "fs-"
and add aliases to all of the filesystems that can be built as modules
to match.

A common practice is to build all of the kernel code and leave code
that is not commonly needed as modules, with the result that many
users are exposed to any bug anywhere in the kernel.

Looking for filesystems with a fs- prefix limits the pool of possible
modules that can be loaded by mount to just filesystems trivially
making things safer with no real cost.

Using aliases means user space can control the policy of which
filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf
with blacklist and alias directives.  Allowing simple, safe,
well understood work-arounds to known problematic software.

This also addresses a rare but unfortunate problem where the filesystem
name is not the same as it's module name and module auto-loading
would not work.  While writing this patch I saw a handful of such
cases.  The most significant being autofs that lives in the module
autofs4.

This is relevant to user namespaces because we can reach the request
module in get_fs_type() without having any special permissions, and
people get uncomfortable when a user specified string (in this case
the filesystem type) goes all of the way to request_module.

After having looked at this issue I don't think there is any
particular reason to perform any filtering or permission checks beyond
making it clear in the module request that we want a filesystem
module.  The common pattern in the kernel is to call request_module()
without regards to the users permissions.  In general all a filesystem
module does once loaded is call register_filesystem() and go to sleep.
Which means there is not much attack surface exposed by loading a
filesytem module unless the filesystem is mounted.  In a user
namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT,
which most filesystems do not set today.

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reported-by: Kees Cook <keescook@google.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2013-03-03 19:36:31 -08:00

1787 lines
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/*
* 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 <linux/cleancache.h>
#include <linux/ratelimit.h>
#include <linux/btrfs.h>
#include "compat.h"
#include "delayed-inode.h"
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "btrfs_inode.h"
#include "print-tree.h"
#include "xattr.h"
#include "volumes.h"
#include "version.h"
#include "export.h"
#include "compression.h"
#include "rcu-string.h"
#include "dev-replace.h"
#define CREATE_TRACE_POINTS
#include <trace/events/btrfs.h>
static const struct super_operations btrfs_super_ops;
static struct file_system_type btrfs_fs_type;
static const char *btrfs_decode_error(int errno, char nbuf[16])
{
char *errstr = NULL;
switch (errno) {
case -EIO:
errstr = "IO failure";
break;
case -ENOMEM:
errstr = "Out of memory";
break;
case -EROFS:
errstr = "Readonly filesystem";
break;
case -EEXIST:
errstr = "Object already exists";
break;
default:
if (nbuf) {
if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
errstr = nbuf;
}
break;
}
return errstr;
}
static void __save_error_info(struct btrfs_fs_info *fs_info)
{
/*
* today we only save the error info into ram. Long term we'll
* also send it down to the disk
*/
set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
}
static void save_error_info(struct btrfs_fs_info *fs_info)
{
__save_error_info(fs_info);
}
/* btrfs handle error by forcing the filesystem readonly */
static void btrfs_handle_error(struct btrfs_fs_info *fs_info)
{
struct super_block *sb = fs_info->sb;
if (sb->s_flags & MS_RDONLY)
return;
if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
sb->s_flags |= MS_RDONLY;
printk(KERN_INFO "btrfs is forced readonly\n");
/*
* Note that a running device replace operation is not
* canceled here although there is no way to update
* the progress. It would add the risk of a deadlock,
* therefore the canceling is ommited. The only penalty
* is that some I/O remains active until the procedure
* completes. The next time when the filesystem is
* mounted writeable again, the device replace
* operation continues.
*/
// WARN_ON(1);
}
}
#ifdef CONFIG_PRINTK
/*
* __btrfs_std_error decodes expected errors from the caller and
* invokes the approciate error response.
*/
void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
unsigned int line, int errno, const char *fmt, ...)
{
struct super_block *sb = fs_info->sb;
char nbuf[16];
const char *errstr;
/*
* Special case: if the error is EROFS, and we're already
* under MS_RDONLY, then it is safe here.
*/
if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
return;
errstr = btrfs_decode_error(errno, nbuf);
if (fmt) {
struct va_format vaf;
va_list args;
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s (%pV)\n",
sb->s_id, function, line, errstr, &vaf);
va_end(args);
} else {
printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n",
sb->s_id, function, line, errstr);
}
/* Don't go through full error handling during mount */
if (sb->s_flags & MS_BORN) {
save_error_info(fs_info);
btrfs_handle_error(fs_info);
}
}
static const char * const logtypes[] = {
"emergency",
"alert",
"critical",
"error",
"warning",
"notice",
"info",
"debug",
};
void btrfs_printk(struct btrfs_fs_info *fs_info, const char *fmt, ...)
{
struct super_block *sb = fs_info->sb;
char lvl[4];
struct va_format vaf;
va_list args;
const char *type = logtypes[4];
int kern_level;
va_start(args, fmt);
kern_level = printk_get_level(fmt);
if (kern_level) {
size_t size = printk_skip_level(fmt) - fmt;
memcpy(lvl, fmt, size);
lvl[size] = '\0';
fmt += size;
type = logtypes[kern_level - '0'];
} else
*lvl = '\0';
vaf.fmt = fmt;
vaf.va = &args;
printk("%sBTRFS %s (device %s): %pV", lvl, type, sb->s_id, &vaf);
va_end(args);
}
#else
void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
unsigned int line, int errno, const char *fmt, ...)
{
struct super_block *sb = fs_info->sb;
/*
* Special case: if the error is EROFS, and we're already
* under MS_RDONLY, then it is safe here.
*/
if (errno == -EROFS && (sb->s_flags & MS_RDONLY))
return;
/* Don't go through full error handling during mount */
if (sb->s_flags & MS_BORN) {
save_error_info(fs_info);
btrfs_handle_error(fs_info);
}
}
#endif
/*
* We only mark the transaction aborted and then set the file system read-only.
* This will prevent new transactions from starting or trying to join this
* one.
*
* This means that error recovery at the call site is limited to freeing
* any local memory allocations and passing the error code up without
* further cleanup. The transaction should complete as it normally would
* in the call path but will return -EIO.
*
* We'll complete the cleanup in btrfs_end_transaction and
* btrfs_commit_transaction.
*/
void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root, const char *function,
unsigned int line, int errno)
{
WARN_ONCE(1, KERN_DEBUG "btrfs: Transaction aborted\n");
trans->aborted = errno;
/* Nothing used. The other threads that have joined this
* transaction may be able to continue. */
if (!trans->blocks_used) {
char nbuf[16];
const char *errstr;
errstr = btrfs_decode_error(errno, nbuf);
btrfs_printk(root->fs_info,
"%s:%d: Aborting unused transaction(%s).\n",
function, line, errstr);
return;
}
ACCESS_ONCE(trans->transaction->aborted) = errno;
__btrfs_std_error(root->fs_info, function, line, errno, NULL);
}
/*
* __btrfs_panic decodes unexpected, fatal errors from the caller,
* issues an alert, and either panics or BUGs, depending on mount options.
*/
void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
unsigned int line, int errno, const char *fmt, ...)
{
char nbuf[16];
char *s_id = "<unknown>";
const char *errstr;
struct va_format vaf = { .fmt = fmt };
va_list args;
if (fs_info)
s_id = fs_info->sb->s_id;
va_start(args, fmt);
vaf.va = &args;
errstr = btrfs_decode_error(errno, nbuf);
if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (%s)\n",
s_id, function, line, &vaf, errstr);
printk(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (%s)\n",
s_id, function, line, &vaf, errstr);
va_end(args);
/* Caller calls BUG() */
}
static void btrfs_put_super(struct super_block *sb)
{
(void)close_ctree(btrfs_sb(sb)->tree_root);
/* FIXME: need to fix VFS to return error? */
/* AV: return it _where_? ->put_super() can be triggered by any number
* of async events, up to and including delivery of SIGKILL to the
* last process that kept it busy. Or segfault in the aforementioned
* process... Whom would you report that to?
*/
}
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_type, Opt_compress_force, Opt_compress_force_type,
Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache,
Opt_no_space_cache, Opt_recovery, Opt_skip_balance,
Opt_check_integrity, Opt_check_integrity_including_extent_data,
Opt_check_integrity_print_mask, Opt_fatal_errors,
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_type, "compress=%s"},
{Opt_compress_force, "compress-force"},
{Opt_compress_force_type, "compress-force=%s"},
{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_space_cache, "space_cache"},
{Opt_clear_cache, "clear_cache"},
{Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
{Opt_enospc_debug, "enospc_debug"},
{Opt_subvolrootid, "subvolrootid=%d"},
{Opt_defrag, "autodefrag"},
{Opt_inode_cache, "inode_cache"},
{Opt_no_space_cache, "nospace_cache"},
{Opt_recovery, "recovery"},
{Opt_skip_balance, "skip_balance"},
{Opt_check_integrity, "check_int"},
{Opt_check_integrity_including_extent_data, "check_int_data"},
{Opt_check_integrity_print_mask, "check_int_print_mask=%d"},
{Opt_fatal_errors, "fatal_errors=%s"},
{Opt_err, NULL},
};
/*
* Regular mount options parser. Everything that is needed only when
* reading in a new superblock is parsed here.
* XXX JDM: This needs to be cleaned up for remount.
*/
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 = NULL;
u64 cache_gen;
int intarg;
int ret = 0;
char *compress_type;
bool compress_force = false;
cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
if (cache_gen)
btrfs_set_opt(info->mount_opt, SPACE_CACHE);
if (!options)
goto out;
/*
* 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_subvolrootid:
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:
if (!btrfs_test_opt(root, COMPRESS) ||
!btrfs_test_opt(root, FORCE_COMPRESS)) {
printk(KERN_INFO "btrfs: setting nodatacow, compression disabled\n");
} else {
printk(KERN_INFO "btrfs: setting nodatacow\n");
}
info->compress_type = BTRFS_COMPRESS_NONE;
btrfs_clear_opt(info->mount_opt, COMPRESS);
btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
btrfs_set_opt(info->mount_opt, NODATACOW);
btrfs_set_opt(info->mount_opt, NODATASUM);
break;
case Opt_compress_force:
case Opt_compress_force_type:
compress_force = true;
/* Fallthrough */
case Opt_compress:
case Opt_compress_type:
if (token == Opt_compress ||
token == Opt_compress_force ||
strcmp(args[0].from, "zlib") == 0) {
compress_type = "zlib";
info->compress_type = BTRFS_COMPRESS_ZLIB;
btrfs_set_opt(info->mount_opt, COMPRESS);
btrfs_clear_opt(info->mount_opt, NODATACOW);
btrfs_clear_opt(info->mount_opt, NODATASUM);
} else if (strcmp(args[0].from, "lzo") == 0) {
compress_type = "lzo";
info->compress_type = BTRFS_COMPRESS_LZO;
btrfs_set_opt(info->mount_opt, COMPRESS);
btrfs_clear_opt(info->mount_opt, NODATACOW);
btrfs_clear_opt(info->mount_opt, NODATASUM);
btrfs_set_fs_incompat(info, COMPRESS_LZO);
} else if (strncmp(args[0].from, "no", 2) == 0) {
compress_type = "no";
info->compress_type = BTRFS_COMPRESS_NONE;
btrfs_clear_opt(info->mount_opt, COMPRESS);
btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
compress_force = false;
} else {
ret = -EINVAL;
goto out;
}
if (compress_force) {
btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
pr_info("btrfs: force %s compression\n",
compress_type);
} else
pr_info("btrfs: use %s compression\n",
compress_type);
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;
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) {
mutex_lock(&info->chunk_mutex);
info->alloc_start = memparse(num, NULL);
mutex_unlock(&info->chunk_mutex);
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_space_cache:
btrfs_set_opt(info->mount_opt, SPACE_CACHE);
break;
case Opt_no_space_cache:
printk(KERN_INFO "btrfs: disabling disk space caching\n");
btrfs_clear_opt(info->mount_opt, SPACE_CACHE);
break;
case Opt_inode_cache:
printk(KERN_INFO "btrfs: enabling inode map caching\n");
btrfs_set_opt(info->mount_opt, INODE_MAP_CACHE);
break;
case Opt_clear_cache:
printk(KERN_INFO "btrfs: force clearing of disk cache\n");
btrfs_set_opt(info->mount_opt, CLEAR_CACHE);
break;
case Opt_user_subvol_rm_allowed:
btrfs_set_opt(info->mount_opt, USER_SUBVOL_RM_ALLOWED);
break;
case Opt_enospc_debug:
btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
break;
case Opt_defrag:
printk(KERN_INFO "btrfs: enabling auto defrag\n");
btrfs_set_opt(info->mount_opt, AUTO_DEFRAG);
break;
case Opt_recovery:
printk(KERN_INFO "btrfs: enabling auto recovery\n");
btrfs_set_opt(info->mount_opt, RECOVERY);
break;
case Opt_skip_balance:
btrfs_set_opt(info->mount_opt, SKIP_BALANCE);
break;
#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
case Opt_check_integrity_including_extent_data:
printk(KERN_INFO "btrfs: enabling check integrity"
" including extent data\n");
btrfs_set_opt(info->mount_opt,
CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
break;
case Opt_check_integrity:
printk(KERN_INFO "btrfs: enabling check integrity\n");
btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
break;
case Opt_check_integrity_print_mask:
intarg = 0;
match_int(&args[0], &intarg);
if (intarg) {
info->check_integrity_print_mask = intarg;
printk(KERN_INFO "btrfs:"
" check_integrity_print_mask 0x%x\n",
info->check_integrity_print_mask);
}
break;
#else
case Opt_check_integrity_including_extent_data:
case Opt_check_integrity:
case Opt_check_integrity_print_mask:
printk(KERN_ERR "btrfs: support for check_integrity*"
" not compiled in!\n");
ret = -EINVAL;
goto out;
#endif
case Opt_fatal_errors:
if (strcmp(args[0].from, "panic") == 0)
btrfs_set_opt(info->mount_opt,
PANIC_ON_FATAL_ERROR);
else if (strcmp(args[0].from, "bug") == 0)
btrfs_clear_opt(info->mount_opt,
PANIC_ON_FATAL_ERROR);
else {
ret = -EINVAL;
goto out;
}
break;
case Opt_err:
printk(KERN_INFO "btrfs: unrecognized mount option "
"'%s'\n", p);
ret = -EINVAL;
goto out;
default:
break;
}
}
out:
if (!ret && btrfs_test_opt(root, SPACE_CACHE))
printk(KERN_INFO "btrfs: disk space caching is enabled\n");
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,
u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices)
{
substring_t args[MAX_OPT_ARGS];
char *device_name, *opts, *orig, *p;
int error = 0;
int intarg;
if (!options)
return 0;
/*
* strsep changes the string, duplicate it because parse_options
* gets called twice
*/
opts = kstrdup(options, GFP_KERNEL);
if (!opts)
return -ENOMEM;
orig = opts;
while ((p = strsep(&opts, ",")) != NULL) {
int token;
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_subvol:
kfree(*subvol_name);
*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_subvolrootid:
intarg = 0;
error = match_int(&args[0], &intarg);
if (!error) {
/* we want the original fs_tree */
if (!intarg)
*subvol_rootid =
BTRFS_FS_TREE_OBJECTID;
else
*subvol_rootid = intarg;
}
break;
case Opt_device:
device_name = match_strdup(&args[0]);
if (!device_name) {
error = -ENOMEM;
goto out;
}
error = btrfs_scan_one_device(device_name,
flags, holder, fs_devices);
kfree(device_name);
if (error)
goto out;
break;
default:
break;
}
}
out:
kfree(orig);
return error;
}
static struct dentry *get_default_root(struct super_block *sb,
u64 subvol_objectid)
{
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
struct btrfs_root *root = fs_info->tree_root;
struct btrfs_root *new_root;
struct btrfs_dir_item *di;
struct btrfs_path *path;
struct btrfs_key location;
struct inode *inode;
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(fs_info->super_copy);
di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0);
if (IS_ERR(di)) {
btrfs_free_path(path);
return ERR_CAST(di);
}
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 = 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(fs_info, &location);
if (IS_ERR(new_root))
return ERR_CAST(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 (IS_ERR(inode))
return ERR_CAST(inode);
/*
* 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);
}
return d_obtain_alias(inode);
}
static int btrfs_fill_super(struct super_block *sb,
struct btrfs_fs_devices *fs_devices,
void *data, int silent)
{
struct inode *inode;
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
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_d_op = &btrfs_dentry_operations;
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
sb->s_flags |= MS_I_VERSION;
err = open_ctree(sb, fs_devices, (char *)data);
if (err) {
printk("btrfs: open_ctree failed\n");
return err;
}
key.objectid = BTRFS_FIRST_FREE_OBJECTID;
key.type = BTRFS_INODE_ITEM_KEY;
key.offset = 0;
inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
goto fail_close;
}
sb->s_root = d_make_root(inode);
if (!sb->s_root) {
err = -ENOMEM;
goto fail_close;
}
save_mount_options(sb, data);
cleancache_init_fs(sb);
sb->s_flags |= MS_ACTIVE;
return 0;
fail_close:
close_ctree(fs_info->tree_root);
return err;
}
int btrfs_sync_fs(struct super_block *sb, int wait)
{
struct btrfs_trans_handle *trans;
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
struct btrfs_root *root = fs_info->tree_root;
trace_btrfs_sync_fs(wait);
if (!wait) {
filemap_flush(fs_info->btree_inode->i_mapping);
return 0;
}
btrfs_wait_ordered_extents(root, 0);
trans = btrfs_attach_transaction_barrier(root);
if (IS_ERR(trans)) {
/* no transaction, don't bother */
if (PTR_ERR(trans) == -ENOENT)
return 0;
return PTR_ERR(trans);
}
return btrfs_commit_transaction(trans, root);
}
static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
{
struct btrfs_fs_info *info = btrfs_sb(dentry->d_sb);
struct btrfs_root *root = info->tree_root;
char *compress_type;
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)) {
if (info->compress_type == BTRFS_COMPRESS_ZLIB)
compress_type = "zlib";
else
compress_type = "lzo";
if (btrfs_test_opt(root, FORCE_COMPRESS))
seq_printf(seq, ",compress-force=%s", compress_type);
else
seq_printf(seq, ",compress=%s", compress_type);
}
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");
if (btrfs_test_opt(root, SPACE_CACHE))
seq_puts(seq, ",space_cache");
else
seq_puts(seq, ",nospace_cache");
if (btrfs_test_opt(root, CLEAR_CACHE))
seq_puts(seq, ",clear_cache");
if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED))
seq_puts(seq, ",user_subvol_rm_allowed");
if (btrfs_test_opt(root, ENOSPC_DEBUG))
seq_puts(seq, ",enospc_debug");
if (btrfs_test_opt(root, AUTO_DEFRAG))
seq_puts(seq, ",autodefrag");
if (btrfs_test_opt(root, INODE_MAP_CACHE))
seq_puts(seq, ",inode_cache");
if (btrfs_test_opt(root, SKIP_BALANCE))
seq_puts(seq, ",skip_balance");
if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
seq_puts(seq, ",fatal_errors=panic");
return 0;
}
static int btrfs_test_super(struct super_block *s, void *data)
{
struct btrfs_fs_info *p = data;
struct btrfs_fs_info *fs_info = btrfs_sb(s);
return fs_info->fs_devices == p->fs_devices;
}
static int btrfs_set_super(struct super_block *s, void *data)
{
int err = set_anon_super(s, data);
if (!err)
s->s_fs_info = data;
return err;
}
/*
* subvolumes are identified by ino 256
*/
static inline int is_subvolume_inode(struct inode *inode)
{
if (inode && inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
return 1;
return 0;
}
/*
* This will strip out the subvol=%s argument for an argument string and add
* subvolid=0 to make sure we get the actual tree root for path walking to the
* subvol we want.
*/
static char *setup_root_args(char *args)
{
unsigned len = strlen(args) + 2 + 1;
char *src, *dst, *buf;
/*
* We need the same args as before, but with this substitution:
* s!subvol=[^,]+!subvolid=0!
*
* Since the replacement string is up to 2 bytes longer than the
* original, allocate strlen(args) + 2 + 1 bytes.
*/
src = strstr(args, "subvol=");
/* This shouldn't happen, but just in case.. */
if (!src)
return NULL;
buf = dst = kmalloc(len, GFP_NOFS);
if (!buf)
return NULL;
/*
* If the subvol= arg is not at the start of the string,
* copy whatever precedes it into buf.
*/
if (src != args) {
*src++ = '\0';
strcpy(buf, args);
dst += strlen(args);
}
strcpy(dst, "subvolid=0");
dst += strlen("subvolid=0");
/*
* If there is a "," after the original subvol=... string,
* copy that suffix into our buffer. Otherwise, we're done.
*/
src = strchr(src, ',');
if (src)
strcpy(dst, src);
return buf;
}
static struct dentry *mount_subvol(const char *subvol_name, int flags,
const char *device_name, char *data)
{
struct dentry *root;
struct vfsmount *mnt;
char *newargs;
newargs = setup_root_args(data);
if (!newargs)
return ERR_PTR(-ENOMEM);
mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name,
newargs);
kfree(newargs);
if (IS_ERR(mnt))
return ERR_CAST(mnt);
root = mount_subtree(mnt, subvol_name);
if (!IS_ERR(root) && !is_subvolume_inode(root->d_inode)) {
struct super_block *s = root->d_sb;
dput(root);
root = ERR_PTR(-EINVAL);
deactivate_locked_super(s);
printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n",
subvol_name);
}
return root;
}
/*
* 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 struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
const char *device_name, void *data)
{
struct block_device *bdev = NULL;
struct super_block *s;
struct dentry *root;
struct btrfs_fs_devices *fs_devices = NULL;
struct btrfs_fs_info *fs_info = NULL;
fmode_t mode = FMODE_READ;
char *subvol_name = NULL;
u64 subvol_objectid = 0;
u64 subvol_rootid = 0;
int error = 0;
if (!(flags & MS_RDONLY))
mode |= FMODE_WRITE;
error = btrfs_parse_early_options(data, mode, fs_type,
&subvol_name, &subvol_objectid,
&subvol_rootid, &fs_devices);
if (error) {
kfree(subvol_name);
return ERR_PTR(error);
}
if (subvol_name) {
root = mount_subvol(subvol_name, flags, device_name, data);
kfree(subvol_name);
return root;
}
error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
if (error)
return ERR_PTR(error);
/*
* Setup a dummy root and fs_info for test/set super. This is because
* we don't actually fill this stuff out until open_ctree, but we need
* it for searching for existing supers, so this lets us do that and
* then open_ctree will properly initialize everything later.
*/
fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
if (!fs_info)
return ERR_PTR(-ENOMEM);
fs_info->fs_devices = fs_devices;
fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
if (!fs_info->super_copy || !fs_info->super_for_commit) {
error = -ENOMEM;
goto error_fs_info;
}
error = btrfs_open_devices(fs_devices, mode, fs_type);
if (error)
goto error_fs_info;
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, btrfs_set_super, flags | MS_NOSEC,
fs_info);
if (IS_ERR(s)) {
error = PTR_ERR(s);
goto error_close_devices;
}
if (s->s_root) {
btrfs_close_devices(fs_devices);
free_fs_info(fs_info);
if ((flags ^ s->s_flags) & MS_RDONLY)
error = -EBUSY;
} else {
char b[BDEVNAME_SIZE];
strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
btrfs_sb(s)->bdev_holder = fs_type;
error = btrfs_fill_super(s, fs_devices, data,
flags & MS_SILENT ? 1 : 0);
}
root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error);
if (IS_ERR(root))
deactivate_locked_super(s);
return root;
error_close_devices:
btrfs_close_devices(fs_devices);
error_fs_info:
free_fs_info(fs_info);
return ERR_PTR(error);
}
static void btrfs_set_max_workers(struct btrfs_workers *workers, int new_limit)
{
spin_lock_irq(&workers->lock);
workers->max_workers = new_limit;
spin_unlock_irq(&workers->lock);
}
static void btrfs_resize_thread_pool(struct btrfs_fs_info *fs_info,
int new_pool_size, int old_pool_size)
{
if (new_pool_size == old_pool_size)
return;
fs_info->thread_pool_size = new_pool_size;
printk(KERN_INFO "btrfs: resize thread pool %d -> %d\n",
old_pool_size, new_pool_size);
btrfs_set_max_workers(&fs_info->generic_worker, new_pool_size);
btrfs_set_max_workers(&fs_info->workers, new_pool_size);
btrfs_set_max_workers(&fs_info->delalloc_workers, new_pool_size);
btrfs_set_max_workers(&fs_info->submit_workers, new_pool_size);
btrfs_set_max_workers(&fs_info->caching_workers, new_pool_size);
btrfs_set_max_workers(&fs_info->fixup_workers, new_pool_size);
btrfs_set_max_workers(&fs_info->endio_workers, new_pool_size);
btrfs_set_max_workers(&fs_info->endio_meta_workers, new_pool_size);
btrfs_set_max_workers(&fs_info->endio_meta_write_workers, new_pool_size);
btrfs_set_max_workers(&fs_info->endio_write_workers, new_pool_size);
btrfs_set_max_workers(&fs_info->endio_freespace_worker, new_pool_size);
btrfs_set_max_workers(&fs_info->delayed_workers, new_pool_size);
btrfs_set_max_workers(&fs_info->readahead_workers, new_pool_size);
btrfs_set_max_workers(&fs_info->scrub_wr_completion_workers,
new_pool_size);
}
static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info,
unsigned long old_opts, int flags)
{
set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
(!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
(flags & MS_RDONLY))) {
/* wait for any defraggers to finish */
wait_event(fs_info->transaction_wait,
(atomic_read(&fs_info->defrag_running) == 0));
if (flags & MS_RDONLY)
sync_filesystem(fs_info->sb);
}
}
static inline void btrfs_remount_cleanup(struct btrfs_fs_info *fs_info,
unsigned long old_opts)
{
/*
* We need cleanup all defragable inodes if the autodefragment is
* close or the fs is R/O.
*/
if (btrfs_raw_test_opt(old_opts, AUTO_DEFRAG) &&
(!btrfs_raw_test_opt(fs_info->mount_opt, AUTO_DEFRAG) ||
(fs_info->sb->s_flags & MS_RDONLY))) {
btrfs_cleanup_defrag_inodes(fs_info);
}
clear_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
}
static int btrfs_remount(struct super_block *sb, int *flags, char *data)
{
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
struct btrfs_root *root = fs_info->tree_root;
unsigned old_flags = sb->s_flags;
unsigned long old_opts = fs_info->mount_opt;
unsigned long old_compress_type = fs_info->compress_type;
u64 old_max_inline = fs_info->max_inline;
u64 old_alloc_start = fs_info->alloc_start;
int old_thread_pool_size = fs_info->thread_pool_size;
unsigned int old_metadata_ratio = fs_info->metadata_ratio;
int ret;
btrfs_remount_prepare(fs_info, old_opts, *flags);
ret = btrfs_parse_options(root, data);
if (ret) {
ret = -EINVAL;
goto restore;
}
btrfs_resize_thread_pool(fs_info,
fs_info->thread_pool_size, old_thread_pool_size);
if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
goto out;
if (*flags & MS_RDONLY) {
/*
* this also happens on 'umount -rf' or on shutdown, when
* the filesystem is busy.
*/
sb->s_flags |= MS_RDONLY;
btrfs_dev_replace_suspend_for_unmount(fs_info);
btrfs_scrub_cancel(fs_info);
ret = btrfs_commit_super(root);
if (ret)
goto restore;
} else {
if (fs_info->fs_devices->rw_devices == 0) {
ret = -EACCES;
goto restore;
}
if (fs_info->fs_devices->missing_devices >
fs_info->num_tolerated_disk_barrier_failures &&
!(*flags & MS_RDONLY)) {
printk(KERN_WARNING
"Btrfs: too many missing devices, writeable remount is not allowed\n");
ret = -EACCES;
goto restore;
}
if (btrfs_super_log_root(fs_info->super_copy) != 0) {
ret = -EINVAL;
goto restore;
}
ret = btrfs_cleanup_fs_roots(fs_info);
if (ret)
goto restore;
/* recover relocation */
ret = btrfs_recover_relocation(root);
if (ret)
goto restore;
ret = btrfs_resume_balance_async(fs_info);
if (ret)
goto restore;
ret = btrfs_resume_dev_replace_async(fs_info);
if (ret) {
pr_warn("btrfs: failed to resume dev_replace\n");
goto restore;
}
sb->s_flags &= ~MS_RDONLY;
}
out:
btrfs_remount_cleanup(fs_info, old_opts);
return 0;
restore:
/* We've hit an error - don't reset MS_RDONLY */
if (sb->s_flags & MS_RDONLY)
old_flags |= MS_RDONLY;
sb->s_flags = old_flags;
fs_info->mount_opt = old_opts;
fs_info->compress_type = old_compress_type;
fs_info->max_inline = old_max_inline;
mutex_lock(&fs_info->chunk_mutex);
fs_info->alloc_start = old_alloc_start;
mutex_unlock(&fs_info->chunk_mutex);
btrfs_resize_thread_pool(fs_info,
old_thread_pool_size, fs_info->thread_pool_size);
fs_info->metadata_ratio = old_metadata_ratio;
btrfs_remount_cleanup(fs_info, old_opts);
return ret;
}
/* Used to sort the devices by max_avail(descending sort) */
static int btrfs_cmp_device_free_bytes(const void *dev_info1,
const void *dev_info2)
{
if (((struct btrfs_device_info *)dev_info1)->max_avail >
((struct btrfs_device_info *)dev_info2)->max_avail)
return -1;
else if (((struct btrfs_device_info *)dev_info1)->max_avail <
((struct btrfs_device_info *)dev_info2)->max_avail)
return 1;
else
return 0;
}
/*
* sort the devices by max_avail, in which max free extent size of each device
* is stored.(Descending Sort)
*/
static inline void btrfs_descending_sort_devices(
struct btrfs_device_info *devices,
size_t nr_devices)
{
sort(devices, nr_devices, sizeof(struct btrfs_device_info),
btrfs_cmp_device_free_bytes, NULL);
}
/*
* The helper to calc the free space on the devices that can be used to store
* file data.
*/
static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
{
struct btrfs_fs_info *fs_info = root->fs_info;
struct btrfs_device_info *devices_info;
struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
struct btrfs_device *device;
u64 skip_space;
u64 type;
u64 avail_space;
u64 used_space;
u64 min_stripe_size;
int min_stripes = 1, num_stripes = 1;
int i = 0, nr_devices;
int ret;
nr_devices = fs_info->fs_devices->open_devices;
BUG_ON(!nr_devices);
devices_info = kmalloc(sizeof(*devices_info) * nr_devices,
GFP_NOFS);
if (!devices_info)
return -ENOMEM;
/* calc min stripe number for data space alloction */
type = btrfs_get_alloc_profile(root, 1);
if (type & BTRFS_BLOCK_GROUP_RAID0) {
min_stripes = 2;
num_stripes = nr_devices;
} else if (type & BTRFS_BLOCK_GROUP_RAID1) {
min_stripes = 2;
num_stripes = 2;
} else if (type & BTRFS_BLOCK_GROUP_RAID10) {
min_stripes = 4;
num_stripes = 4;
}
if (type & BTRFS_BLOCK_GROUP_DUP)
min_stripe_size = 2 * BTRFS_STRIPE_LEN;
else
min_stripe_size = BTRFS_STRIPE_LEN;
list_for_each_entry(device, &fs_devices->devices, dev_list) {
if (!device->in_fs_metadata || !device->bdev ||
device->is_tgtdev_for_dev_replace)
continue;
avail_space = device->total_bytes - device->bytes_used;
/* align with stripe_len */
do_div(avail_space, BTRFS_STRIPE_LEN);
avail_space *= BTRFS_STRIPE_LEN;
/*
* In order to avoid overwritting the superblock on the drive,
* btrfs starts at an offset of at least 1MB when doing chunk
* allocation.
*/
skip_space = 1024 * 1024;
/* user can set the offset in fs_info->alloc_start. */
if (fs_info->alloc_start + BTRFS_STRIPE_LEN <=
device->total_bytes)
skip_space = max(fs_info->alloc_start, skip_space);
/*
* btrfs can not use the free space in [0, skip_space - 1],
* we must subtract it from the total. In order to implement
* it, we account the used space in this range first.
*/
ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1,
&used_space);
if (ret) {
kfree(devices_info);
return ret;
}
/* calc the free space in [0, skip_space - 1] */
skip_space -= used_space;
/*
* we can use the free space in [0, skip_space - 1], subtract
* it from the total.
*/
if (avail_space && avail_space >= skip_space)
avail_space -= skip_space;
else
avail_space = 0;
if (avail_space < min_stripe_size)
continue;
devices_info[i].dev = device;
devices_info[i].max_avail = avail_space;
i++;
}
nr_devices = i;
btrfs_descending_sort_devices(devices_info, nr_devices);
i = nr_devices - 1;
avail_space = 0;
while (nr_devices >= min_stripes) {
if (num_stripes > nr_devices)
num_stripes = nr_devices;
if (devices_info[i].max_avail >= min_stripe_size) {
int j;
u64 alloc_size;
avail_space += devices_info[i].max_avail * num_stripes;
alloc_size = devices_info[i].max_avail;
for (j = i + 1 - num_stripes; j <= i; j++)
devices_info[j].max_avail -= alloc_size;
}
i--;
nr_devices--;
}
kfree(devices_info);
*free_bytes = avail_space;
return 0;
}
static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
{
struct btrfs_fs_info *fs_info = btrfs_sb(dentry->d_sb);
struct btrfs_super_block *disk_super = fs_info->super_copy;
struct list_head *head = &fs_info->space_info;
struct btrfs_space_info *found;
u64 total_used = 0;
u64 total_free_data = 0;
int bits = dentry->d_sb->s_blocksize_bits;
__be32 *fsid = (__be32 *)fs_info->fsid;
int ret;
/* holding chunk_muext to avoid allocating new chunks */
mutex_lock(&fs_info->chunk_mutex);
rcu_read_lock();
list_for_each_entry_rcu(found, head, list) {
if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
total_free_data += found->disk_total - found->disk_used;
total_free_data -=
btrfs_account_ro_block_groups_free_space(found);
}
total_used += found->disk_used;
}
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_bsize = dentry->d_sb->s_blocksize;
buf->f_type = BTRFS_SUPER_MAGIC;
buf->f_bavail = total_free_data;
ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
if (ret) {
mutex_unlock(&fs_info->chunk_mutex);
return ret;
}
buf->f_bavail += total_free_data;
buf->f_bavail = buf->f_bavail >> bits;
mutex_unlock(&fs_info->chunk_mutex);
/* 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 void btrfs_kill_super(struct super_block *sb)
{
struct btrfs_fs_info *fs_info = btrfs_sb(sb);
kill_anon_super(sb);
free_fs_info(fs_info);
}
static struct file_system_type btrfs_fs_type = {
.owner = THIS_MODULE,
.name = "btrfs",
.mount = btrfs_mount,
.kill_sb = btrfs_kill_super,
.fs_flags = FS_REQUIRES_DEV,
};
MODULE_ALIAS_FS("btrfs");
/*
* 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;
case BTRFS_IOC_DEVICES_READY:
ret = btrfs_scan_one_device(vol->name, FMODE_READ,
&btrfs_fs_type, &fs_devices);
if (ret)
break;
ret = !(fs_devices->num_devices == fs_devices->total_devices);
break;
}
kfree(vol);
return ret;
}
static int btrfs_freeze(struct super_block *sb)
{
struct btrfs_trans_handle *trans;
struct btrfs_root *root = btrfs_sb(sb)->tree_root;
trans = btrfs_attach_transaction_barrier(root);
if (IS_ERR(trans)) {
/* no transaction, don't bother */
if (PTR_ERR(trans) == -ENOENT)
return 0;
return PTR_ERR(trans);
}
return btrfs_commit_transaction(trans, root);
}
static int btrfs_unfreeze(struct super_block *sb)
{
return 0;
}
static int btrfs_show_devname(struct seq_file *m, struct dentry *root)
{
struct btrfs_fs_info *fs_info = btrfs_sb(root->d_sb);
struct btrfs_fs_devices *cur_devices;
struct btrfs_device *dev, *first_dev = NULL;
struct list_head *head;
struct rcu_string *name;
mutex_lock(&fs_info->fs_devices->device_list_mutex);
cur_devices = fs_info->fs_devices;
while (cur_devices) {
head = &cur_devices->devices;
list_for_each_entry(dev, head, dev_list) {
if (dev->missing)
continue;
if (!first_dev || dev->devid < first_dev->devid)
first_dev = dev;
}
cur_devices = cur_devices->seed;
}
if (first_dev) {
rcu_read_lock();
name = rcu_dereference(first_dev->name);
seq_escape(m, name->str, " \t\n\\");
rcu_read_unlock();
} else {
WARN_ON(1);
}
mutex_unlock(&fs_info->fs_devices->device_list_mutex);
return 0;
}
static const struct super_operations btrfs_super_ops = {
.drop_inode = btrfs_drop_inode,
.evict_inode = btrfs_evict_inode,
.put_super = btrfs_put_super,
.sync_fs = btrfs_sync_fs,
.show_options = btrfs_show_options,
.show_devname = btrfs_show_devname,
.write_inode = btrfs_write_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,
.llseek = noop_llseek,
};
static struct miscdevice btrfs_misc = {
.minor = BTRFS_MINOR,
.name = "btrfs-control",
.fops = &btrfs_ctl_fops
};
MODULE_ALIAS_MISCDEV(BTRFS_MINOR);
MODULE_ALIAS("devname:btrfs-control");
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 "btrfs: misc_deregister failed for control device\n");
}
static int __init init_btrfs_fs(void)
{
int err;
err = btrfs_init_sysfs();
if (err)
return err;
btrfs_init_compress();
err = btrfs_init_cachep();
if (err)
goto free_compress;
err = extent_io_init();
if (err)
goto free_cachep;
err = extent_map_init();
if (err)
goto free_extent_io;
err = ordered_data_init();
if (err)
goto free_extent_map;
err = btrfs_delayed_inode_init();
if (err)
goto free_ordered_data;
err = btrfs_auto_defrag_init();
if (err)
goto free_delayed_inode;
err = btrfs_delayed_ref_init();
if (err)
goto free_auto_defrag;
err = btrfs_interface_init();
if (err)
goto free_delayed_ref;
err = register_filesystem(&btrfs_fs_type);
if (err)
goto unregister_ioctl;
btrfs_init_lockdep();
printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
return 0;
unregister_ioctl:
btrfs_interface_exit();
free_delayed_ref:
btrfs_delayed_ref_exit();
free_auto_defrag:
btrfs_auto_defrag_exit();
free_delayed_inode:
btrfs_delayed_inode_exit();
free_ordered_data:
ordered_data_exit();
free_extent_map:
extent_map_exit();
free_extent_io:
extent_io_exit();
free_cachep:
btrfs_destroy_cachep();
free_compress:
btrfs_exit_compress();
btrfs_exit_sysfs();
return err;
}
static void __exit exit_btrfs_fs(void)
{
btrfs_destroy_cachep();
btrfs_delayed_ref_exit();
btrfs_auto_defrag_exit();
btrfs_delayed_inode_exit();
ordered_data_exit();
extent_map_exit();
extent_io_exit();
btrfs_interface_exit();
unregister_filesystem(&btrfs_fs_type);
btrfs_exit_sysfs();
btrfs_cleanup_fs_uuids();
btrfs_exit_compress();
}
module_init(init_btrfs_fs)
module_exit(exit_btrfs_fs)
MODULE_LICENSE("GPL");
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