[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit
Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/os/linux/linux-3.4.x/fs/btrfs/super.c b/ap/os/linux/linux-3.4.x/fs/btrfs/super.c
new file mode 100644
index 0000000..c5f8fca
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/fs/btrfs/super.c
@@ -0,0 +1,1578 @@
+/*
+ * 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 "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;
+ 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
+ */
+ 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_scrub_cancel(fs_info);
+// WARN_ON(1);
+ }
+}
+
+/*
+ * __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;
+ va_list args;
+ va_start(args, fmt);
+
+ /*
+ * 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);
+ if (fmt) {
+ struct va_format vaf = {
+ .fmt = fmt,
+ .va = &args,
+ };
+
+ printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s (%pV)\n",
+ sb->s_id, function, line, errstr, &vaf);
+ } 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);
+ }
+ va_end(args);
+}
+
+const char *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];
+
+ va_start(args, fmt);
+
+ if (fmt[0] == '<' && isdigit(fmt[1]) && fmt[2] == '>') {
+ strncpy(lvl, fmt, 3);
+ fmt += 3;
+ type = logtypes[fmt[1] - '0'];
+ } else
+ *lvl = '\0';
+
+ vaf.fmt = fmt;
+ vaf.va = &args;
+ printk("%sBTRFS %s (device %s): %pV", lvl, type, sb->s_id, &vaf);
+}
+
+/*
+ * 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");
+ trans->aborted = errno;
+ /* Nothing used. The other threads that have joined this
+ * transaction may be able to continue. */
+ if (!trans->blocks_used) {
+ btrfs_printk(root->fs_info, "Aborting unused transaction.\n");
+ return;
+ }
+ 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(fs_info, errno, nbuf);
+ if (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:
+ 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_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
+
+ 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;
+ int ret;
+
+ trace_btrfs_sync_fs(wait);
+
+ if (!wait) {
+ filemap_flush(fs_info->btree_inode->i_mapping);
+ return 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 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 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 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, 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];
+
+ s->s_flags = flags | MS_NOSEC;
+ 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 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;
+
+ ret = btrfs_parse_options(root, data);
+ if (ret) {
+ ret = -EINVAL;
+ goto restore;
+ }
+
+ 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);
+ if (ret)
+ goto restore;
+ } else {
+ if (fs_info->fs_devices->rw_devices == 0) {
+ 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;
+
+ sb->s_flags &= ~MS_RDONLY;
+ }
+
+ 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;
+ fs_info->alloc_start = old_alloc_start;
+ fs_info->thread_pool_size = old_thread_pool_size;
+ fs_info->metadata_ratio = old_metadata_ratio;
+ 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)
+ 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,
+};
+
+/*
+ * 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_fs_info *fs_info = btrfs_sb(sb);
+ mutex_lock(&fs_info->transaction_kthread_mutex);
+ mutex_lock(&fs_info->cleaner_mutex);
+ return 0;
+}
+
+static int btrfs_unfreeze(struct super_block *sb)
+{
+ struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+ mutex_unlock(&fs_info->cleaner_mutex);
+ mutex_unlock(&fs_info->transaction_kthread_mutex);
+ return 0;
+}
+
+static void btrfs_fs_dirty_inode(struct inode *inode, int flags)
+{
+ int ret;
+
+ ret = btrfs_dirty_inode(inode);
+ if (ret)
+ printk_ratelimited(KERN_ERR "btrfs: fail to dirty inode %Lu "
+ "error %d\n", btrfs_ino(inode), ret);
+}
+
+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_fs_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;
+
+ 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 = 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;
+
+ btrfs_init_lockdep();
+
+ 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();
+ 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");