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05dbe6837b
linux/fs/btrfs/super.c
Omar Sandoval 05dbe6837b Btrfs: unify subvol= and subvolid= mounting 
Currently, mounting a subvolume with subvolid= takes a different code
path than mounting with subvol=. This isn't really a big deal except for
the fact that mounts done with subvolid= or the default subvolume don't
have a dentry that's connected to the dentry tree like in the subvol=
case. To unify the code paths, when given subvolid= or using the default
subvolume ID, translate it into a subvolume name by walking
ROOT_BACKREFs in the root tree and INODE_REFs in the filesystem trees.

Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Chris Mason <clm@fb.com>
2015-06-03 04:03:01 -07:00

2328 lines
59 KiB
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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 "delayed-inode.h"
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "btrfs_inode.h"
#include "print-tree.h"
#include "hash.h"
#include "props.h"
#include "xattr.h"
#include "volumes.h"
#include "export.h"
#include "compression.h"
#include "rcu-string.h"
#include "dev-replace.h"
#include "free-space-cache.h"
#include "backref.h"
#include "tests/btrfs-tests.h"
#include "qgroup.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 int btrfs_remount(struct super_block *sb, int *flags, char *data);
static const char *btrfs_decode_error(int errno)
{
char *errstr = "unknown";
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;
case -ENOSPC:
errstr = "No space left";
break;
case -ENOENT:
errstr = "No such entry";
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);
}
/* 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;
btrfs_info(fs_info, "forced readonly");
/*
* 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.
*/
}
}
#ifdef CONFIG_PRINTK
/*
* __btrfs_std_error decodes expected errors from the caller and
* invokes the approciate error response.
*/
__cold
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;
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);
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: errno=%d %s (%pV)\n",
sb->s_id, function, line, errno, errstr, &vaf);
va_end(args);
} else {
printk(KERN_CRIT "BTRFS: error (device %s) in %s:%d: errno=%d %s\n",
sb->s_id, function, line, errno, errstr);
}
/* Don't go through full error handling during mount */
save_error_info(fs_info);
if (sb->s_flags & MS_BORN)
btrfs_handle_error(fs_info);
}
static const char * const logtypes[] = {
"emergency",
"alert",
"critical",
"error",
"warning",
"notice",
"info",
"debug",
};
void btrfs_printk(const 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\n", 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.
*/
__cold
void __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
struct btrfs_root *root, const char *function,
unsigned int line, int errno)
{
trans->aborted = errno;
/* Nothing used. The other threads that have joined this
* transaction may be able to continue. */
if (!trans->blocks_used && list_empty(&trans->new_bgs)) {
const char *errstr;
errstr = btrfs_decode_error(errno);
btrfs_warn(root->fs_info,
"%s:%d: Aborting unused transaction(%s).",
function, line, errstr);
return;
}
ACCESS_ONCE(trans->transaction->aborted) = errno;
/* Wake up anybody who may be waiting on this transaction */
wake_up(&root->fs_info->transaction_wait);
wake_up(&root->fs_info->transaction_blocked_wait);
__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.
*/
__cold
void __btrfs_panic(struct btrfs_fs_info *fs_info, const char *function,
unsigned int line, int errno, const char *fmt, ...)
{
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);
if (fs_info && (fs_info->mount_opt & BTRFS_MOUNT_PANIC_ON_FATAL_ERROR))
panic(KERN_CRIT "BTRFS panic (device %s) in %s:%d: %pV (errno=%d %s)\n",
s_id, function, line, &vaf, errno, errstr);
btrfs_crit(fs_info, "panic in %s:%d: %pV (errno=%d %s)",
function, line, &vaf, errno, errstr);
va_end(args);
/* Caller calls BUG() */
}
static void btrfs_put_super(struct super_block *sb)
{
close_ctree(btrfs_sb(sb)->tree_root);
}
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_rescan_uuid_tree,
Opt_commit_interval, Opt_barrier, Opt_nodefrag, Opt_nodiscard,
Opt_noenospc_debug, Opt_noflushoncommit, Opt_acl, Opt_datacow,
Opt_datasum, Opt_treelog, Opt_noinode_cache,
Opt_err,
};
static match_table_t tokens = {
{Opt_degraded, "degraded"},
{Opt_subvol, "subvol=%s"},
{Opt_subvolid, "subvolid=%s"},
{Opt_device, "device=%s"},
{Opt_nodatasum, "nodatasum"},
{Opt_datasum, "datasum"},
{Opt_nodatacow, "nodatacow"},
{Opt_datacow, "datacow"},
{Opt_nobarrier, "nobarrier"},
{Opt_barrier, "barrier"},
{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_acl, "acl"},
{Opt_noacl, "noacl"},
{Opt_notreelog, "notreelog"},
{Opt_treelog, "treelog"},
{Opt_flushoncommit, "flushoncommit"},
{Opt_noflushoncommit, "noflushoncommit"},
{Opt_ratio, "metadata_ratio=%d"},
{Opt_discard, "discard"},
{Opt_nodiscard, "nodiscard"},
{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_noenospc_debug, "noenospc_debug"},
{Opt_subvolrootid, "subvolrootid=%d"},
{Opt_defrag, "autodefrag"},
{Opt_nodefrag, "noautodefrag"},
{Opt_inode_cache, "inode_cache"},
{Opt_noinode_cache, "noinode_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_rescan_uuid_tree, "rescan_uuid_tree"},
{Opt_fatal_errors, "fatal_errors=%s"},
{Opt_commit_interval, "commit=%d"},
{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:
btrfs_info(root->fs_info, "allowing degraded mounts");
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:
btrfs_set_and_info(root, NODATASUM,
"setting nodatasum");
break;
case Opt_datasum:
if (btrfs_test_opt(root, NODATASUM)) {
if (btrfs_test_opt(root, NODATACOW))
btrfs_info(root->fs_info, "setting datasum, datacow enabled");
else
btrfs_info(root->fs_info, "setting datasum");
}
btrfs_clear_opt(info->mount_opt, NODATACOW);
btrfs_clear_opt(info->mount_opt, NODATASUM);
break;
case Opt_nodatacow:
if (!btrfs_test_opt(root, NODATACOW)) {
if (!btrfs_test_opt(root, COMPRESS) ||
!btrfs_test_opt(root, FORCE_COMPRESS)) {
btrfs_info(root->fs_info,
"setting nodatacow, compression disabled");
} else {
btrfs_info(root->fs_info, "setting nodatacow");
}
}
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_datacow:
btrfs_clear_and_info(root, NODATACOW,
"setting datacow");
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";
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_and_info(root, FORCE_COMPRESS,
"force %s compression",
compress_type);
} else {
if (!btrfs_test_opt(root, COMPRESS))
btrfs_info(root->fs_info,
"btrfs: use %s compression",
compress_type);
/*
* If we remount from compress-force=xxx to
* compress=xxx, we need clear FORCE_COMPRESS
* flag, otherwise, there is no way for users
* to disable forcible compression separately.
*/
btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
}
break;
case Opt_ssd:
btrfs_set_and_info(root, SSD,
"use ssd allocation scheme");
break;
case Opt_ssd_spread:
btrfs_set_and_info(root, SSD_SPREAD,
"use spread ssd allocation scheme");
btrfs_set_opt(info->mount_opt, SSD);
break;
case Opt_nossd:
btrfs_set_and_info(root, NOSSD,
"not using ssd allocation scheme");
btrfs_clear_opt(info->mount_opt, SSD);
break;
case Opt_barrier:
btrfs_clear_and_info(root, NOBARRIER,
"turning on barriers");
break;
case Opt_nobarrier:
btrfs_set_and_info(root, NOBARRIER,
"turning off barriers");
break;
case Opt_thread_pool:
ret = match_int(&args[0], &intarg);
if (ret) {
goto out;
} else if (intarg > 0) {
info->thread_pool_size = intarg;
} else {
ret = -EINVAL;
goto out;
}
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 = min_t(u64,
info->max_inline,
root->sectorsize);
}
btrfs_info(root->fs_info, "max_inline at %llu",
info->max_inline);
} else {
ret = -ENOMEM;
goto out;
}
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);
btrfs_info(root->fs_info, "allocations start at %llu",
info->alloc_start);
} else {
ret = -ENOMEM;
goto out;
}
break;
case Opt_acl:
#ifdef CONFIG_BTRFS_FS_POSIX_ACL
root->fs_info->sb->s_flags |= MS_POSIXACL;
break;
#else
btrfs_err(root->fs_info,
"support for ACL not compiled in!");
ret = -EINVAL;
goto out;
#endif
case Opt_noacl:
root->fs_info->sb->s_flags &= ~MS_POSIXACL;
break;
case Opt_notreelog:
btrfs_set_and_info(root, NOTREELOG,
"disabling tree log");
break;
case Opt_treelog:
btrfs_clear_and_info(root, NOTREELOG,
"enabling tree log");
break;
case Opt_flushoncommit:
btrfs_set_and_info(root, FLUSHONCOMMIT,
"turning on flush-on-commit");
break;
case Opt_noflushoncommit:
btrfs_clear_and_info(root, FLUSHONCOMMIT,
"turning off flush-on-commit");
break;
case Opt_ratio:
ret = match_int(&args[0], &intarg);
if (ret) {
goto out;
} else if (intarg >= 0) {
info->metadata_ratio = intarg;
btrfs_info(root->fs_info, "metadata ratio %d",
info->metadata_ratio);
} else {
ret = -EINVAL;
goto out;
}
break;
case Opt_discard:
btrfs_set_and_info(root, DISCARD,
"turning on discard");
break;
case Opt_nodiscard:
btrfs_clear_and_info(root, DISCARD,
"turning off discard");
break;
case Opt_space_cache:
btrfs_set_and_info(root, SPACE_CACHE,
"enabling disk space caching");
break;
case Opt_rescan_uuid_tree:
btrfs_set_opt(info->mount_opt, RESCAN_UUID_TREE);
break;
case Opt_no_space_cache:
btrfs_clear_and_info(root, SPACE_CACHE,
"disabling disk space caching");
break;
case Opt_inode_cache:
btrfs_set_pending_and_info(info, INODE_MAP_CACHE,
"enabling inode map caching");
break;
case Opt_noinode_cache:
btrfs_clear_pending_and_info(info, INODE_MAP_CACHE,
"disabling inode map caching");
break;
case Opt_clear_cache:
btrfs_set_and_info(root, CLEAR_CACHE,
"force clearing of disk 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_noenospc_debug:
btrfs_clear_opt(info->mount_opt, ENOSPC_DEBUG);
break;
case Opt_defrag:
btrfs_set_and_info(root, AUTO_DEFRAG,
"enabling auto defrag");
break;
case Opt_nodefrag:
btrfs_clear_and_info(root, AUTO_DEFRAG,
"disabling auto defrag");
break;
case Opt_recovery:
btrfs_info(root->fs_info, "enabling auto recovery");
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:
btrfs_info(root->fs_info,
"enabling check integrity including extent data");
btrfs_set_opt(info->mount_opt,
CHECK_INTEGRITY_INCLUDING_EXTENT_DATA);
btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
break;
case Opt_check_integrity:
btrfs_info(root->fs_info, "enabling check integrity");
btrfs_set_opt(info->mount_opt, CHECK_INTEGRITY);
break;
case Opt_check_integrity_print_mask:
ret = match_int(&args[0], &intarg);
if (ret) {
goto out;
} else if (intarg >= 0) {
info->check_integrity_print_mask = intarg;
btrfs_info(root->fs_info, "check_integrity_print_mask 0x%x",
info->check_integrity_print_mask);
} else {
ret = -EINVAL;
goto out;
}
break;
#else
case Opt_check_integrity_including_extent_data:
case Opt_check_integrity:
case Opt_check_integrity_print_mask:
btrfs_err(root->fs_info,
"support for check_integrity* not compiled in!");
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_commit_interval:
intarg = 0;
ret = match_int(&args[0], &intarg);
if (ret < 0) {
btrfs_err(root->fs_info, "invalid commit interval");
ret = -EINVAL;
goto out;
}
if (intarg > 0) {
if (intarg > 300) {
btrfs_warn(root->fs_info, "excessive commit interval %d",
intarg);
}
info->commit_interval = intarg;
} else {
btrfs_info(root->fs_info, "using default commit interval %ds",
BTRFS_DEFAULT_COMMIT_INTERVAL);
info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
}
break;
case Opt_err:
btrfs_info(root->fs_info, "unrecognized mount option '%s'", p);
ret = -EINVAL;
goto out;
default:
break;
}
}
out:
if (!ret && btrfs_test_opt(root, SPACE_CACHE))
btrfs_info(root->fs_info, "disk space caching is enabled");
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 *device_name, *opts, *orig, *p;
char *num = NULL;
int error = 0;
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]);
if (!*subvol_name) {
error = -ENOMEM;
goto out;
}
break;
case Opt_subvolid:
num = match_strdup(&args[0]);
if (num) {
*subvol_objectid = memparse(num, NULL);
kfree(num);
/* we want the original fs_tree */
if (!*subvol_objectid)
*subvol_objectid =
BTRFS_FS_TREE_OBJECTID;
} else {
error = -EINVAL;
goto out;
}
break;
case Opt_subvolrootid:
printk(KERN_WARNING
"BTRFS: 'subvolrootid' mount option is deprecated and has "
"no effect\n");
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 char *get_subvol_name_from_objectid(struct btrfs_fs_info *fs_info,
u64 subvol_objectid)
{
struct btrfs_root *root = fs_info->tree_root;
struct btrfs_root *fs_root;
struct btrfs_root_ref *root_ref;
struct btrfs_inode_ref *inode_ref;
struct btrfs_key key;
struct btrfs_path *path = NULL;
char *name = NULL, *ptr;
u64 dirid;
int len;
int ret;
path = btrfs_alloc_path();
if (!path) {
ret = -ENOMEM;
goto err;
}
path->leave_spinning = 1;
name = kmalloc(PATH_MAX, GFP_NOFS);
if (!name) {
ret = -ENOMEM;
goto err;
}
ptr = name + PATH_MAX - 1;
ptr[0] = '\0';
/*
* Walk up the subvolume trees in the tree of tree roots by root
* backrefs until we hit the top-level subvolume.
*/
while (subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
key.objectid = subvol_objectid;
key.type = BTRFS_ROOT_BACKREF_KEY;
key.offset = (u64)-1;
ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
if (ret < 0) {
goto err;
} else if (ret > 0) {
ret = btrfs_previous_item(root, path, subvol_objectid,
BTRFS_ROOT_BACKREF_KEY);
if (ret < 0) {
goto err;
} else if (ret > 0) {
ret = -ENOENT;
goto err;
}
}
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
subvol_objectid = key.offset;
root_ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
struct btrfs_root_ref);
len = btrfs_root_ref_name_len(path->nodes[0], root_ref);
ptr -= len + 1;
if (ptr < name) {
ret = -ENAMETOOLONG;
goto err;
}
read_extent_buffer(path->nodes[0], ptr + 1,
(unsigned long)(root_ref + 1), len);
ptr[0] = '/';
dirid = btrfs_root_ref_dirid(path->nodes[0], root_ref);
btrfs_release_path(path);
key.objectid = subvol_objectid;
key.type = BTRFS_ROOT_ITEM_KEY;
key.offset = (u64)-1;
fs_root = btrfs_read_fs_root_no_name(fs_info, &key);
if (IS_ERR(fs_root)) {
ret = PTR_ERR(fs_root);
goto err;
}
/*
* Walk up the filesystem tree by inode refs until we hit the
* root directory.
*/
while (dirid != BTRFS_FIRST_FREE_OBJECTID) {
key.objectid = dirid;
key.type = BTRFS_INODE_REF_KEY;
key.offset = (u64)-1;
ret = btrfs_search_slot(NULL, fs_root, &key, path, 0, 0);
if (ret < 0) {
goto err;
} else if (ret > 0) {
ret = btrfs_previous_item(fs_root, path, dirid,
BTRFS_INODE_REF_KEY);
if (ret < 0) {
goto err;
} else if (ret > 0) {
ret = -ENOENT;
goto err;
}
}
btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
dirid = key.offset;
inode_ref = btrfs_item_ptr(path->nodes[0],
path->slots[0],
struct btrfs_inode_ref);
len = btrfs_inode_ref_name_len(path->nodes[0],
inode_ref);
ptr -= len + 1;
if (ptr < name) {
ret = -ENAMETOOLONG;
goto err;
}
read_extent_buffer(path->nodes[0], ptr + 1,
(unsigned long)(inode_ref + 1), len);
ptr[0] = '/';
btrfs_release_path(path);
}
}
btrfs_free_path(path);
if (ptr == name + PATH_MAX - 1) {
name[0] = '/';
name[1] = '\0';
} else {
memmove(name, ptr, name + PATH_MAX - ptr);
}
return name;
err:
btrfs_free_path(path);
kfree(name);
return ERR_PTR(ret);
}
static int get_default_subvol_objectid(struct btrfs_fs_info *fs_info, u64 *objectid)
{
struct btrfs_root *root = fs_info->tree_root;
struct btrfs_dir_item *di;
struct btrfs_path *path;
struct btrfs_key location;
u64 dir_id;
path = btrfs_alloc_path();
if (!path)
return -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 PTR_ERR(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 the top-level subvolume.
*/
btrfs_free_path(path);
*objectid = BTRFS_FS_TREE_OBJECTID;
return 0;
}
btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location);
btrfs_free_path(path);
*objectid = location.objectid;
return 0;
}
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(KERN_ERR "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_roots(fs_info, -1);
trans = btrfs_attach_transaction_barrier(root);
if (IS_ERR(trans)) {
/* no transaction, don't bother */
if (PTR_ERR(trans) == -ENOENT) {
/*
* Exit unless we have some pending changes
* that need to go through commit
*/
if (fs_info->pending_changes == 0)
return 0;
/*
* A non-blocking test if the fs is frozen. We must not
* start a new transaction here otherwise a deadlock
* happens. The pending operations are delayed to the
* next commit after thawing.
*/
if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
__sb_end_write(sb, SB_FREEZE_WRITE);
else
return 0;
trans = btrfs_start_transaction(root, 0);
}
if (IS_ERR(trans))
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 != BTRFS_DEFAULT_MAX_INLINE)
seq_printf(seq, ",max_inline=%llu", info->max_inline);
if (info->alloc_start != 0)
seq_printf(seq, ",alloc_start=%llu", 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, RESCAN_UUID_TREE))
seq_puts(seq, ",rescan_uuid_tree");
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, RECOVERY))
seq_puts(seq, ",recovery");
#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
if (btrfs_test_opt(root, CHECK_INTEGRITY_INCLUDING_EXTENT_DATA))
seq_puts(seq, ",check_int_data");
else if (btrfs_test_opt(root, CHECK_INTEGRITY))
seq_puts(seq, ",check_int");
if (info->check_integrity_print_mask)
seq_printf(seq, ",check_int_print_mask=%d",
info->check_integrity_print_mask);
#endif
if (info->metadata_ratio)
seq_printf(seq, ",metadata_ratio=%d",
info->metadata_ratio);
if (btrfs_test_opt(root, PANIC_ON_FATAL_ERROR))
seq_puts(seq, ",fatal_errors=panic");
if (info->commit_interval != BTRFS_DEFAULT_COMMIT_INTERVAL)
seq_printf(seq, ",commit=%d", info->commit_interval);
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 add subvolid=0 to the argument string while removing any subvol=
* and subvolid= arguments to make sure we get the top-level root for path
* walking to the subvol we want.
*/
static char *setup_root_args(char *args)
{
char *buf, *dst, *sep;
if (!args)
return kstrdup("subvolid=0", GFP_NOFS);
/* The worst case is that we add ",subvolid=0" to the end. */
buf = dst = kmalloc(strlen(args) + strlen(",subvolid=0") + 1, GFP_NOFS);
if (!buf)
return NULL;
while (1) {
sep = strchrnul(args, ',');
if (!strstarts(args, "subvol=") &&
!strstarts(args, "subvolid=")) {
memcpy(dst, args, sep - args);
dst += sep - args;
*dst++ = ',';
}
if (*sep)
args = sep + 1;
else
break;
}
strcpy(dst, "subvolid=0");
return buf;
}
static struct dentry *mount_subvol(const char *subvol_name, u64 subvol_objectid,
int flags, const char *device_name,
char *data)
{
struct dentry *root;
struct vfsmount *mnt = NULL;
char *newargs;
int ret;
newargs = setup_root_args(data);
if (!newargs) {
root = ERR_PTR(-ENOMEM);
goto out;
}
mnt = vfs_kern_mount(&btrfs_fs_type, flags, device_name, newargs);
if (PTR_ERR_OR_ZERO(mnt) == -EBUSY) {
if (flags & MS_RDONLY) {
mnt = vfs_kern_mount(&btrfs_fs_type, flags & ~MS_RDONLY,
device_name, newargs);
} else {
mnt = vfs_kern_mount(&btrfs_fs_type, flags | MS_RDONLY,
device_name, newargs);
if (IS_ERR(mnt)) {
root = ERR_CAST(mnt);
mnt = NULL;
goto out;
}
down_write(&mnt->mnt_sb->s_umount);
ret = btrfs_remount(mnt->mnt_sb, &flags, NULL);
up_write(&mnt->mnt_sb->s_umount);
if (ret < 0) {
root = ERR_PTR(ret);
goto out;
}
}
}
if (IS_ERR(mnt)) {
root = ERR_CAST(mnt);
mnt = NULL;
goto out;
}
if (!subvol_name) {
if (!subvol_objectid) {
ret = get_default_subvol_objectid(btrfs_sb(mnt->mnt_sb),
&subvol_objectid);
if (ret) {
root = ERR_PTR(ret);
goto out;
}
}
subvol_name = get_subvol_name_from_objectid(btrfs_sb(mnt->mnt_sb),
subvol_objectid);
if (IS_ERR(subvol_name)) {
root = ERR_CAST(subvol_name);
subvol_name = NULL;
goto out;
}
}
root = mount_subtree(mnt, subvol_name);
/* mount_subtree() drops our reference on the vfsmount. */
mnt = NULL;
if (!IS_ERR(root)) {
struct super_block *s = root->d_sb;
struct inode *root_inode = d_inode(root);
u64 root_objectid = BTRFS_I(root_inode)->root->root_key.objectid;
ret = 0;
if (!is_subvolume_inode(root_inode)) {
pr_err("BTRFS: '%s' is not a valid subvolume\n",
subvol_name);
ret = -EINVAL;
}
if (subvol_objectid && root_objectid != subvol_objectid) {
/*
* This will also catch a race condition where a
* subvolume which was passed by ID is renamed and
* another subvolume is renamed over the old location.
*/
pr_err("BTRFS: subvol '%s' does not match subvolid %llu\n",
subvol_name, subvol_objectid);
ret = -EINVAL;
}
if (ret) {
dput(root);
root = ERR_PTR(ret);
deactivate_locked_super(s);
}
}
out:
mntput(mnt);
kfree(newargs);
kfree(subvol_name);
return root;
}
static int parse_security_options(char *orig_opts,
struct security_mnt_opts *sec_opts)
{
char *secdata = NULL;
int ret = 0;
secdata = alloc_secdata();
if (!secdata)
return -ENOMEM;
ret = security_sb_copy_data(orig_opts, secdata);
if (ret) {
free_secdata(secdata);
return ret;
}
ret = security_sb_parse_opts_str(secdata, sec_opts);
free_secdata(secdata);
return ret;
}
static int setup_security_options(struct btrfs_fs_info *fs_info,
struct super_block *sb,
struct security_mnt_opts *sec_opts)
{
int ret = 0;
/*
* Call security_sb_set_mnt_opts() to check whether new sec_opts
* is valid.
*/
ret = security_sb_set_mnt_opts(sb, sec_opts, 0, NULL);
if (ret)
return ret;
#ifdef CONFIG_SECURITY
if (!fs_info->security_opts.num_mnt_opts) {
/* first time security setup, copy sec_opts to fs_info */
memcpy(&fs_info->security_opts, sec_opts, sizeof(*sec_opts));
} else {
/*
* Since SELinux(the only one supports security_mnt_opts) does
* NOT support changing context during remount/mount same sb,
* This must be the same or part of the same security options,
* just free it.
*/
security_free_mnt_opts(sec_opts);
}
#endif
return ret;
}
/*
* Find a superblock for the given device / mount point.
*
* Note: This is based on get_sb_bdev from fs/super.c with a few additions
* for multiple device setup. Make sure to keep it in sync.
*/
static 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 btrfs_fs_devices *fs_devices = NULL;
struct btrfs_fs_info *fs_info = NULL;
struct security_mnt_opts new_sec_opts;
fmode_t mode = FMODE_READ;
char *subvol_name = NULL;
u64 subvol_objectid = 0;
int error = 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) {
kfree(subvol_name);
return ERR_PTR(error);
}
if (subvol_name || subvol_objectid != BTRFS_FS_TREE_OBJECTID) {
/* mount_subvol() will free subvol_name. */
return mount_subvol(subvol_name, subvol_objectid, flags,
device_name, data);
}
security_init_mnt_opts(&new_sec_opts);
if (data) {
error = parse_security_options(data, &new_sec_opts);
if (error)
return ERR_PTR(error);
}
error = btrfs_scan_one_device(device_name, mode, fs_type, &fs_devices);
if (error)
goto error_sec_opts;
/*
* 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) {
error = -ENOMEM;
goto error_sec_opts;
}
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);
security_init_mnt_opts(&fs_info->security_opts);
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);
}
if (error) {
deactivate_locked_super(s);
goto error_sec_opts;
}
fs_info = btrfs_sb(s);
error = setup_security_options(fs_info, s, &new_sec_opts);
if (error) {
deactivate_locked_super(s);
goto error_sec_opts;
}
return dget(s->s_root);
error_close_devices:
btrfs_close_devices(fs_devices);
error_fs_info:
free_fs_info(fs_info);
error_sec_opts:
security_free_mnt_opts(&new_sec_opts);
return ERR_PTR(error);
}
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;
btrfs_info(fs_info, "resize thread pool %d -> %d",
old_pool_size, new_pool_size);
btrfs_workqueue_set_max(fs_info->workers, new_pool_size);
btrfs_workqueue_set_max(fs_info->delalloc_workers, new_pool_size);
btrfs_workqueue_set_max(fs_info->submit_workers, new_pool_size);
btrfs_workqueue_set_max(fs_info->caching_workers, new_pool_size);
btrfs_workqueue_set_max(fs_info->endio_workers, new_pool_size);
btrfs_workqueue_set_max(fs_info->endio_meta_workers, new_pool_size);
btrfs_workqueue_set_max(fs_info->endio_meta_write_workers,
new_pool_size);
btrfs_workqueue_set_max(fs_info->endio_write_workers, new_pool_size);
btrfs_workqueue_set_max(fs_info->endio_freespace_worker, new_pool_size);
btrfs_workqueue_set_max(fs_info->delayed_workers, new_pool_size);
btrfs_workqueue_set_max(fs_info->readahead_workers, new_pool_size);
btrfs_workqueue_set_max(fs_info->scrub_wr_completion_workers,
new_pool_size);
}
static inline void btrfs_remount_prepare(struct btrfs_fs_info *fs_info)
{
set_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state);
}
static inline void btrfs_remount_begin(struct btrfs_fs_info *fs_info,
unsigned long old_opts, int flags)
{
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;
sync_filesystem(sb);
btrfs_remount_prepare(fs_info);
if (data) {
struct security_mnt_opts new_sec_opts;
security_init_mnt_opts(&new_sec_opts);
ret = parse_security_options(data, &new_sec_opts);
if (ret)
goto restore;
ret = setup_security_options(fs_info, sb,
&new_sec_opts);
if (ret) {
security_free_mnt_opts(&new_sec_opts);
goto restore;
}
}
ret = btrfs_parse_options(root, data);
if (ret) {
ret = -EINVAL;
goto restore;
}
btrfs_remount_begin(fs_info, old_opts, *flags);
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.
*/
cancel_work_sync(&fs_info->async_reclaim_work);
/* wait for the uuid_scan task to finish */
down(&fs_info->uuid_tree_rescan_sem);
/* avoid complains from lockdep et al. */
up(&fs_info->uuid_tree_rescan_sem);
sb->s_flags |= MS_RDONLY;
btrfs_dev_replace_suspend_for_unmount(fs_info);
btrfs_scrub_cancel(fs_info);
btrfs_pause_balance(fs_info);
ret = btrfs_commit_super(root);
if (ret)
goto restore;
} else {
if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
btrfs_err(fs_info,
"Remounting read-write after error is not allowed");
ret = -EINVAL;
goto restore;
}
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)) {
btrfs_warn(fs_info,
"too many missing devices, writeable remount is not allowed");
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 */
mutex_lock(&fs_info->cleaner_mutex);
ret = btrfs_recover_relocation(root);
mutex_unlock(&fs_info->cleaner_mutex);
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) {
btrfs_warn(fs_info, "failed to resume dev_replace");
goto restore;
}
if (!fs_info->uuid_root) {
btrfs_info(fs_info, "creating UUID tree");
ret = btrfs_create_uuid_tree(fs_info);
if (ret) {
btrfs_warn(fs_info, "failed to create the UUID tree %d", ret);
goto restore;
}
}
sb->s_flags &= ~MS_RDONLY;
}
out:
wake_up_process(fs_info->transaction_kthread);
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;
/*
* We aren't under the device list lock, so this is racey-ish, but good
* enough for our purposes.
*/
nr_devices = fs_info->fs_devices->open_devices;
if (!nr_devices) {
smp_mb();
nr_devices = fs_info->fs_devices->open_devices;
ASSERT(nr_devices);
if (!nr_devices) {
*free_bytes = 0;
return 0;
}
}
devices_info = kmalloc_array(nr_devices, sizeof(*devices_info),
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;
if (fs_info->alloc_start)
mutex_lock(&fs_devices->device_list_mutex);
rcu_read_lock();
list_for_each_entry_rcu(device, &fs_devices->devices, dev_list) {
if (!device->in_fs_metadata || !device->bdev ||
device->is_tgtdev_for_dev_replace)
continue;
if (i >= nr_devices)
break;
avail_space = device->total_bytes - device->bytes_used;
/* align with stripe_len */
avail_space = div_u64(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 &&
fs_info->alloc_start + BTRFS_STRIPE_LEN <=
device->total_bytes) {
rcu_read_unlock();
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);
mutex_unlock(&fs_devices->device_list_mutex);
return ret;
}
rcu_read_lock();
/* 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++;
}
rcu_read_unlock();
if (fs_info->alloc_start)
mutex_unlock(&fs_devices->device_list_mutex);
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;
}
/*
* Calculate numbers for 'df', pessimistic in case of mixed raid profiles.
*
* If there's a redundant raid level at DATA block groups, use the respective
* multiplier to scale the sizes.
*
* Unused device space usage is based on simulating the chunk allocator
* algorithm that respects the device sizes, order of allocations and the
* 'alloc_start' value, this is a close approximation of the actual use but
* there are other factors that may change the result (like a new metadata
* chunk).
*
* FIXME: not accurate for mixed block groups, total and free/used are ok,
* available appears slightly larger.
*/
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;
unsigned factor = 1;
struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
int ret;
/*
* holding chunk_muext to avoid allocating new chunks, holding
* device_list_mutex to avoid the device being removed
*/
rcu_read_lock();
list_for_each_entry_rcu(found, head, list) {
if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
int i;
total_free_data += found->disk_total - found->disk_used;
total_free_data -=
btrfs_account_ro_block_groups_free_space(found);
for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
if (!list_empty(&found->block_groups[i])) {
switch (i) {
case BTRFS_RAID_DUP:
case BTRFS_RAID_RAID1:
case BTRFS_RAID_RAID10:
factor = 2;
}
}
}
}
total_used += found->disk_used;
}
rcu_read_unlock();
buf->f_blocks = div_u64(btrfs_super_total_bytes(disk_super), factor);
buf->f_blocks >>= bits;
buf->f_bfree = buf->f_blocks - (div_u64(total_used, factor) >> bits);
/* Account global block reserve as used, it's in logical size already */
spin_lock(&block_rsv->lock);
buf->f_bfree -= block_rsv->size >> bits;
spin_unlock(&block_rsv->lock);
buf->f_bavail = div_u64(total_free_data, factor);
ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
if (ret)
return ret;
buf->f_bavail += div_u64(total_free_data, factor);
buf->f_bavail = buf->f_bavail >> bits;
buf->f_type = BTRFS_SUPER_MAGIC;
buf->f_bsize = dentry->d_sb->s_blocksize;
buf->f_namelen = BTRFS_NAME_LEN;
/* 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(d_inode(dentry))->root->objectid >> 32;
buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->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 | FS_BINARY_MOUNTDATA,
};
MODULE_ALIAS_FS("btrfs");
static int btrfs_control_open(struct inode *inode, struct file *file)
{
/*
* The control file's private_data is used to hold the
* transaction when it is started and is used to keep
* track of whether a transaction is already in progress.
*/
file->private_data = NULL;
return 0;
}
/*
* 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_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 (!dev->name)
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,
};
static const struct file_operations btrfs_ctl_fops = {
.open = btrfs_control_open,
.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 void btrfs_print_info(void)
{
printk(KERN_INFO "Btrfs loaded"
#ifdef CONFIG_BTRFS_DEBUG
", debug=on"
#endif
#ifdef CONFIG_BTRFS_ASSERT
", assert=on"
#endif
#ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
", integrity-checker=on"
#endif
"\n");
}
static int btrfs_run_sanity_tests(void)
{
int ret;
ret = btrfs_init_test_fs();
if (ret)
return ret;
ret = btrfs_test_free_space_cache();
if (ret)
goto out;
ret = btrfs_test_extent_buffer_operations();
if (ret)
goto out;
ret = btrfs_test_extent_io();
if (ret)
goto out;
ret = btrfs_test_inodes();
if (ret)
goto out;
ret = btrfs_test_qgroups();
out:
btrfs_destroy_test_fs();
return ret;
}
static int __init init_btrfs_fs(void)
{
int err;
err = btrfs_hash_init();
if (err)
return err;
btrfs_props_init();
err = btrfs_init_sysfs();
if (err)
goto free_hash;
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_prelim_ref_init();
if (err)
goto free_delayed_ref;
err = btrfs_end_io_wq_init();
if (err)
goto free_prelim_ref;
err = btrfs_interface_init();
if (err)
goto free_end_io_wq;
btrfs_init_lockdep();
btrfs_print_info();
err = btrfs_run_sanity_tests();
if (err)
goto unregister_ioctl;
err = register_filesystem(&btrfs_fs_type);
if (err)
goto unregister_ioctl;
return 0;
unregister_ioctl:
btrfs_interface_exit();
free_end_io_wq:
btrfs_end_io_wq_exit();
free_prelim_ref:
btrfs_prelim_ref_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();
free_hash:
btrfs_hash_exit();
return err;
}
static void __exit exit_btrfs_fs(void)
{
btrfs_destroy_cachep();
btrfs_delayed_ref_exit();
btrfs_auto_defrag_exit();
btrfs_delayed_inode_exit();
btrfs_prelim_ref_exit();
ordered_data_exit();
extent_map_exit();
extent_io_exit();
btrfs_interface_exit();
btrfs_end_io_wq_exit();
unregister_filesystem(&btrfs_fs_type);
btrfs_exit_sysfs();
btrfs_cleanup_fs_uuids();
btrfs_exit_compress();
btrfs_hash_exit();
}
late_initcall(init_btrfs_fs);
module_exit(exit_btrfs_fs)
MODULE_LICENSE("GPL");
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