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OpenCloudOS-Kernel/fs/btrfs/super.c

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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/mnt_namespace.h>
#include "compat.h"
#include "delayed-inode.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"
#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(struct btrfs_fs_info *fs_info, 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;
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
*/
fs_info->fs_state = BTRFS_SUPER_FLAG_ERROR;
}
/* NOTE:
* We move write_super stuff at umount in order to avoid deadlock
* for umount hold all lock.
*/
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 (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
sb->s_flags |= MS_RDONLY;
printk(KERN_INFO "btrfs is forced readonly\n");
}
}
/*
* __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)
{
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(fs_info, errno, nbuf);
printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n",
sb->s_id, function, line, errstr);
save_error_info(fs_info);
btrfs_handle_error(fs_info);
}
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;
(void)ret; /* FIXME: need to fix VFS to return error? */
}
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_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, "no_space_cache"},
{Opt_recovery, "recovery"},
{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 = 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:
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_force:
case Opt_compress_force_type:
compress_force = true;
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;
} else if (strcmp(args[0].from, "lzo") == 0) {
compress_type = "lzo";
info->compress_type = BTRFS_COMPRESS_LZO;
} else {
ret = -EINVAL;
goto out;
}
btrfs_set_opt(info->mount_opt, COMPRESS);
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;
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_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");
btrfs_set_opt(info->mount_opt, AUTO_DEFRAG);
break;
case Opt_recovery:
printk(KERN_INFO "btrfs: enabling auto recovery");
btrfs_set_opt(info->mount_opt, RECOVERY);
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:
*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_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;
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 (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 = 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_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 dentry *root_dentry;
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_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
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;
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);
cleancache_init_fs(sb);
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;
trace_btrfs_sync_fs(wait);
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, 0);
if (IS_ERR(trans))
return PTR_ERR(trans);
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;
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, ",no_space_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");
return 0;
}
static int btrfs_test_super(struct super_block *s, void *data)
{
struct btrfs_root *test_root = data;
struct btrfs_root *root = btrfs_sb(s);
/*
* If this super block is going away, return false as it
* can't match as an existing super block.
*/
if (!atomic_read(&s->s_active))
return 0;
return root->fs_info->fs_devices == test_root->fs_info->fs_devices;
}
static int btrfs_set_super(struct super_block *s, void *data)
{
s->s_fs_info = data;
return set_anon_super(s, data);
}
/*
* 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 copied = 0;
unsigned len = strlen(args) + 2;
char *pos;
char *ret;
/*
* We need the same args as before, but minus
*
* subvol=a
*
* and add
*
* subvolid=0
*
* which is a difference of 2 characters, so we allocate strlen(args) +
* 2 characters.
*/
ret = kzalloc(len * sizeof(char), GFP_NOFS);
if (!ret)
return NULL;
pos = strstr(args, "subvol=");
/* This shouldn't happen, but just in case.. */
if (!pos) {
kfree(ret);
return NULL;
}
/*
* The subvol=<> arg is not at the front of the string, copy everybody
* up to that into ret.
*/
if (pos != args) {
*pos = '\0';
strcpy(ret, args);
copied += strlen(args);
pos++;
}
strncpy(ret + copied, "subvolid=0", len - copied);
/* Length of subvolid=0 */
copied += 10;
/*
* If there is no , after the subvol= option then we know there's no
* other options and we can just return.
*/
pos = strchr(pos, ',');
if (!pos)
return ret;
/* Copy the rest of the arguments into our buffer */
strncpy(ret + copied, pos, len - copied);
copied += strlen(pos);
return ret;
}
static struct dentry *mount_subvol(const char *subvol_name, int flags,
const char *device_name, char *data)
{
struct super_block *s;
struct dentry *root;
struct vfsmount *mnt;
struct mnt_namespace *ns_private;
char *newargs;
struct path path;
int error;
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);
ns_private = create_mnt_ns(mnt);
if (IS_ERR(ns_private)) {
mntput(mnt);
return ERR_CAST(ns_private);
}
/*
* This will trigger the automount of the subvol so we can just
* drop the mnt we have here and return the dentry that we
* found.
*/
error = vfs_path_lookup(mnt->mnt_root, mnt, subvol_name,
LOOKUP_FOLLOW, &path);
put_mnt_ns(ns_private);
if (error)
return ERR_PTR(error);
if (!is_subvolume_inode(path.dentry->d_inode)) {
path_put(&path);
mntput(mnt);
error = -EINVAL;
printk(KERN_ERR "btrfs: '%s' is not a valid subvolume\n",
subvol_name);
return ERR_PTR(-EINVAL);
}
/* Get a ref to the sb and the dentry we found and return it */
s = path.mnt->mnt_sb;
atomic_inc(&s->s_active);
root = dget(path.dentry);
path_put(&path);
down_write(&s->s_umount);
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_root *tree_root = 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)
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);
error = btrfs_open_devices(fs_devices, mode, fs_type);
if (error)
return ERR_PTR(error);
if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
error = -EACCES;
goto error_close_devices;
}
/*
* 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);
tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
if (!fs_info || !tree_root) {
error = -ENOMEM;
goto error_close_devices;
}
fs_info->tree_root = tree_root;
fs_info->fs_devices = fs_devices;
tree_root->fs_info = fs_info;
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_close_devices;
}
bdev = fs_devices->latest_bdev;
s = sget(fs_type, btrfs_test_super, btrfs_set_super, tree_root);
if (IS_ERR(s)) {
error = PTR_ERR(s);
goto error_close_devices;
}
if (s->s_root) {
if ((flags ^ s->s_flags) & MS_RDONLY) {
deactivate_locked_super(s);
return ERR_PTR(-EBUSY);
}
btrfs_close_devices(fs_devices);
free_fs_info(fs_info);
kfree(tree_root);
} else {
char b[BDEVNAME_SIZE];
s->s_flags = flags | MS_NOSEC;
strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
btrfs_sb(s)->fs_info->bdev_holder = fs_type;
error = btrfs_fill_super(s, fs_devices, data,
flags & MS_SILENT ? 1 : 0);
if (error) {
deactivate_locked_super(s);
return ERR_PTR(error);
}
s->s_flags |= MS_ACTIVE;
}
root = get_default_root(s, subvol_objectid);
if (IS_ERR(root)) {
deactivate_locked_super(s);
return root;
}
return root;
error_close_devices:
btrfs_close_devices(fs_devices);
free_fs_info(fs_info);
kfree(tree_root);
return ERR_PTR(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;
ret = btrfs_cleanup_fs_roots(root->fs_info);
WARN_ON(ret);
/* recover relocation */
ret = btrfs_recover_relocation(root);
WARN_ON(ret);
sb->s_flags &= ~MS_RDONLY;
}
return 0;
}
/* 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;
int i = 0, nr_devices;
int ret;
nr_devices = fs_info->fs_devices->rw_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;
else if (type & BTRFS_BLOCK_GROUP_RAID1)
min_stripes = 2;
else if (type & BTRFS_BLOCK_GROUP_RAID10)
min_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->alloc_list, dev_alloc_list) {
if (!device->in_fs_metadata)
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 (devices_info[i].max_avail >= min_stripe_size) {
int j;
u64 alloc_size;
avail_space += devices_info[i].max_avail * min_stripes;
alloc_size = devices_info[i].max_avail;
for (j = i + 1 - min_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_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 total_free_data = 0;
int bits = dentry->d_sb->s_blocksize_bits;
__be32 *fsid = (__be32 *)root->fs_info->fsid;
int ret;
/* holding chunk_muext to avoid allocating new chunks */
mutex_lock(&root->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(root, &total_free_data);
if (ret) {
mutex_unlock(&root->fs_info->chunk_mutex);
return ret;
}
buf->f_bavail += total_free_data;
buf->f_bavail = buf->f_bavail >> bits;
mutex_unlock(&root->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 struct file_system_type btrfs_fs_type = {
.owner = THIS_MODULE,
.name = "btrfs",
.mount = btrfs_mount,
.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,
.evict_inode = btrfs_evict_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,
.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 "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_compress();
if (err)
goto free_sysfs;
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 = btrfs_delayed_inode_init();
if (err)
goto free_extent_map;
err = btrfs_interface_init();
if (err)
goto free_delayed_inode;
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_delayed_inode:
btrfs_delayed_inode_exit();
free_extent_map:
extent_map_exit();
free_extent_io:
extent_io_exit();
free_cachep:
btrfs_destroy_cachep();
free_compress:
btrfs_exit_compress();
free_sysfs:
btrfs_exit_sysfs();
return err;
}
static void __exit exit_btrfs_fs(void)
{
btrfs_destroy_cachep();
btrfs_delayed_inode_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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