This provides the normal super operations for btrfs.
It also has the ioctl used to scan devices for btrfs filesystems.
Signed-off-by: Chris Mason <chris.mason@xxxxxxxxxx>
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
new file mode 100644
index 0000000..b4c101d
--- /dev/null
+++ b/fs/btrfs/super.c
@@ -0,0 +1,720 @@
+/*
+ * 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/string.h>
+#include <linux/smp_lock.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/version.h>
+#include "compat.h"
+#include "ctree.h"
+#include "disk-io.h"
+#include "transaction.h"
+#include "btrfs_inode.h"
+#include "ioctl.h"
+#include "print-tree.h"
+#include "xattr.h"
+#include "volumes.h"
+#include "version.h"
+#include "export.h"
+#include "compression.h"
+
+#define BTRFS_SUPER_MAGIC 0x9123683E
+
+static struct super_operations btrfs_super_ops;
+
+static void btrfs_put_super(struct super_block *sb)
+{
+ struct btrfs_root *root = btrfs_sb(sb);
+ int ret;
+
+ ret = close_ctree(root);
+ sb->s_fs_info = NULL;
+}
+
+enum {
+ Opt_degraded, Opt_subvol, Opt_device, Opt_nodatasum, Opt_nodatacow,
+ Opt_max_extent, Opt_max_inline, Opt_alloc_start, Opt_nobarrier,
+ Opt_ssd, Opt_thread_pool, Opt_noacl, Opt_compress, Opt_err,
+};
+
+static match_table_t tokens = {
+ {Opt_degraded, "degraded"},
+ {Opt_subvol, "subvol=%s"},
+ {Opt_device, "device=%s"},
+ {Opt_nodatasum, "nodatasum"},
+ {Opt_nodatacow, "nodatacow"},
+ {Opt_nobarrier, "nobarrier"},
+ {Opt_max_extent, "max_extent=%s"},
+ {Opt_max_inline, "max_inline=%s"},
+ {Opt_alloc_start, "alloc_start=%s"},
+ {Opt_thread_pool, "thread_pool=%d"},
+ {Opt_compress, "compress"},
+ {Opt_ssd, "ssd"},
+ {Opt_noacl, "noacl"},
+ {Opt_err, NULL},
+};
+
+u64 btrfs_parse_size(char *str)
+{
+ u64 res;
+ int mult = 1;
+ char *end;
+ char last;
+
+ res = simple_strtoul(str, &end, 10);
+
+ last = end[0];
+ if (isalpha(last)) {
+ last = tolower(last);
+ switch (last) {
+ case 'g':
+ mult *= 1024;
+ case 'm':
+ mult *= 1024;
+ case 'k':
+ mult *= 1024;
+ }
+ res = res * mult;
+ }
+ return res;
+}
+
+/*
+ * Regular mount options parser. Everything that is needed only when
+ * reading in a new superblock is parsed here.
+ */
+int btrfs_parse_options(struct btrfs_root *root, char *options)
+{
+ struct btrfs_fs_info *info = root->fs_info;
+ substring_t args[MAX_OPT_ARGS];
+ char *p, *num;
+ int intarg;
+
+ if (!options)
+ return 0;
+
+ /*
+ * strsep changes the string, duplicate it because parse_options
+ * gets called twice
+ */
+ options = kstrdup(options, GFP_NOFS);
+ if (!options)
+ return -ENOMEM;
+
+
+ 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_device:
+ /*
+ * These are parsed by btrfs_parse_early_options
+ * and can be happily ignored here.
+ */
+ break;
+ case Opt_nodatasum:
+ printk(KERN_INFO "btrfs: setting nodatacsum\n");
+ btrfs_set_opt(info->mount_opt, NODATASUM);
+ break;
+ case Opt_nodatacow:
+ printk(KERN_INFO "btrfs: setting nodatacow\n");
+ btrfs_set_opt(info->mount_opt, NODATACOW);
+ btrfs_set_opt(info->mount_opt, NODATASUM);
+ break;
+ case Opt_compress:
+ printk(KERN_INFO "btrfs: use compression\n");
+ btrfs_set_opt(info->mount_opt, COMPRESS);
+ break;
+ case Opt_ssd:
+ printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
+ btrfs_set_opt(info->mount_opt, SSD);
+ 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_extent:
+ num = match_strdup(&args[0]);
+ if (num) {
+ info->max_extent = btrfs_parse_size(num);
+ kfree(num);
+
+ info->max_extent = max_t(u64,
+ info->max_extent, root->sectorsize);
+ printk(KERN_INFO "btrfs: max_extent at %llu\n",
+ info->max_extent);
+ }
+ break;
+ case Opt_max_inline:
+ num = match_strdup(&args[0]);
+ if (num) {
+ info->max_inline = btrfs_parse_size(num);
+ 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",
+ info->max_inline);
+ }
+ break;
+ case Opt_alloc_start:
+ num = match_strdup(&args[0]);
+ if (num) {
+ info->alloc_start = btrfs_parse_size(num);
+ kfree(num);
+ printk(KERN_INFO
+ "btrfs: allocations start at %llu\n",
+ info->alloc_start);
+ }
+ break;
+ case Opt_noacl:
+ root->fs_info->sb->s_flags &= ~MS_POSIXACL;
+ break;
+ default:
+ break;
+ }
+ }
+ kfree(options);
+ return 0;
+}
+
+/*
+ * 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,
+ struct btrfs_fs_devices **fs_devices)
+{
+ substring_t args[MAX_OPT_ARGS];
+ char *opts, *p;
+ int error = 0;
+
+ if (!options)
+ goto out;
+
+ /*
+ * strsep changes the string, duplicate it because parse_options
+ * gets called twice
+ */
+ opts = kstrdup(options, GFP_KERNEL);
+ if (!opts)
+ return -ENOMEM;
+
+ while ((p = strsep(&opts, ",")) != NULL) {
+ int token;
+ if (!*p)
+ continue;
+
+ token = match_token(p, tokens, args);
+ switch (token) {
+ case Opt_subvol:
+ *subvol_name = match_strdup(&args[0]);
+ break;
+ case Opt_device:
+ error = btrfs_scan_one_device(match_strdup(&args[0]),
+ flags, holder, fs_devices);
+ if (error)
+ goto out_free_opts;
+ break;
+ default:
+ break;
+ }
+ }
+
+ out_free_opts:
+ kfree(opts);
+ out:
+ /*
+ * If no subvolume name is specified we use the default one. Allocate
+ * a copy of the string "." here so that code later in the
+ * mount path doesn't care if it's the default volume or another one.
+ */
+ if (!*subvol_name) {
+ *subvol_name = kstrdup(".", GFP_KERNEL);
+ if (!*subvol_name)
+ return -ENOMEM;
+ }
+ return error;
+}
+
+static int btrfs_fill_super(struct super_block *sb,
+ struct btrfs_fs_devices *fs_devices,
+ void *data, int silent)
+{
+ struct inode *inode;
+ struct dentry *root_dentry;
+ struct btrfs_super_block *disk_super;
+ struct btrfs_root *tree_root;
+ struct btrfs_inode *bi;
+ int err;
+
+ sb->s_maxbytes = MAX_LFS_FILESIZE;
+ sb->s_magic = BTRFS_SUPER_MAGIC;
+ sb->s_op = &btrfs_super_ops;
+ sb->s_export_op = &btrfs_export_ops;
+ sb->s_xattr = btrfs_xattr_handlers;
+ sb->s_time_gran = 1;
+ sb->s_flags |= MS_POSIXACL;
+
+ tree_root = open_ctree(sb, fs_devices, (char *)data);
+
+ if (IS_ERR(tree_root)) {
+ printk("btrfs: open_ctree failed\n");
+ return PTR_ERR(tree_root);
+ }
+ sb->s_fs_info = tree_root;
+ disk_super = &tree_root->fs_info->super_copy;
+ inode = btrfs_iget_locked(sb, BTRFS_FIRST_FREE_OBJECTID,
+ tree_root->fs_info->fs_root);
+ bi = BTRFS_I(inode);
+ bi->location.objectid = inode->i_ino;
+ bi->location.offset = 0;
+ bi->root = tree_root->fs_info->fs_root;
+
+ btrfs_set_key_type(&bi->location, BTRFS_INODE_ITEM_KEY);
+
+ if (!inode) {
+ err = -ENOMEM;
+ goto fail_close;
+ }
+ if (inode->i_state & I_NEW) {
+ btrfs_read_locked_inode(inode);
+ unlock_new_inode(inode);
+ }
+
+ root_dentry = d_alloc_root(inode);
+ if (!root_dentry) {
+ iput(inode);
+ err = -ENOMEM;
+ goto fail_close;
+ }
+#if 0
+ /* this does the super kobj at the same time */
+ err = btrfs_sysfs_add_super(tree_root->fs_info);
+ if (err)
+ goto fail_close;
+#endif
+
+ sb->s_root = root_dentry;
+
+ save_mount_options(sb, data);
+ return 0;
+
+fail_close:
+ close_ctree(tree_root);
+ return err;
+}
+
+int btrfs_sync_fs(struct super_block *sb, int wait)
+{
+ struct btrfs_trans_handle *trans;
+ struct btrfs_root *root;
+ int ret;
+ root = btrfs_sb(sb);
+
+ if (sb->s_flags & MS_RDONLY)
+ return 0;
+
+ sb->s_dirt = 0;
+ if (!wait) {
+ filemap_flush(root->fs_info->btree_inode->i_mapping);
+ return 0;
+ }
+
+ btrfs_start_delalloc_inodes(root);
+ btrfs_wait_ordered_extents(root, 0);
+
+ btrfs_clean_old_snapshots(root);
+ trans = btrfs_start_transaction(root, 1);
+ ret = btrfs_commit_transaction(trans, root);
+ sb->s_dirt = 0;
+ return ret;
+}
+
+static void btrfs_write_super(struct super_block *sb)
+{
+ sb->s_dirt = 0;
+}
+
+static int btrfs_test_super(struct super_block *s, void *data)
+{
+ struct btrfs_fs_devices *test_fs_devices = data;
+ struct btrfs_root *root = btrfs_sb(s);
+
+ return root->fs_info->fs_devices == test_fs_devices;
+}
+
+/*
+ * Find a superblock for the given device / mount point.
+ *
+ * Note: This is based on get_sb_bdev from fs/super.c with a few additions
+ * for multiple device setup. Make sure to keep it in sync.
+ */
+static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
+ const char *dev_name, void *data, struct vfsmount *mnt)
+{
+ char *subvol_name = NULL;
+ struct block_device *bdev = NULL;
+ struct super_block *s;
+ struct dentry *root;
+ struct btrfs_fs_devices *fs_devices = NULL;
+ fmode_t mode = FMODE_READ;
+ int error = 0;
+
+ if (!(flags & MS_RDONLY))
+ mode |= FMODE_WRITE;
+
+ error = btrfs_parse_early_options(data, mode, fs_type,
+ &subvol_name, &fs_devices);
+ if (error)
+ return error;
+
+ error = btrfs_scan_one_device(dev_name, mode, fs_type, &fs_devices);
+ if (error)
+ goto error_free_subvol_name;
+
+ error = btrfs_open_devices(fs_devices, mode, fs_type);
+ if (error)
+ goto error_free_subvol_name;
+
+ if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) {
+ error = -EACCES;
+ goto error_close_devices;
+ }
+
+ bdev = fs_devices->latest_bdev;
+ s = sget(fs_type, btrfs_test_super, set_anon_super, fs_devices);
+ if (IS_ERR(s))
+ goto error_s;
+
+ if (s->s_root) {
+ if ((flags ^ s->s_flags) & MS_RDONLY) {
+ up_write(&s->s_umount);
+ deactivate_super(s);
+ error = -EBUSY;
+ goto error_close_devices;
+ }
+
+ btrfs_close_devices(fs_devices);
+ } else {
+ char b[BDEVNAME_SIZE];
+
+ s->s_flags = flags;
+ strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id));
+ error = btrfs_fill_super(s, fs_devices, data,
+ flags & MS_SILENT ? 1 : 0);
+ if (error) {
+ up_write(&s->s_umount);
+ deactivate_super(s);
+ goto error_free_subvol_name;
+ }
+
+ btrfs_sb(s)->fs_info->bdev_holder = fs_type;
+ s->s_flags |= MS_ACTIVE;
+ }
+
+ if (!strcmp(subvol_name, "."))
+ root = dget(s->s_root);
+ else {
+ mutex_lock(&s->s_root->d_inode->i_mutex);
+ root = lookup_one_len(subvol_name, s->s_root,
+ strlen(subvol_name));
+ mutex_unlock(&s->s_root->d_inode->i_mutex);
+
+ if (IS_ERR(root)) {
+ up_write(&s->s_umount);
+ deactivate_super(s);
+ error = PTR_ERR(root);
+ goto error_free_subvol_name;
+ }
+ if (!root->d_inode) {
+ dput(root);
+ up_write(&s->s_umount);
+ deactivate_super(s);
+ error = -ENXIO;
+ goto error_free_subvol_name;
+ }
+ }
+
+ mnt->mnt_sb = s;
+ mnt->mnt_root = root;
+
+ kfree(subvol_name);
+ return 0;
+
+error_s:
+ error = PTR_ERR(s);
+error_close_devices:
+ btrfs_close_devices(fs_devices);
+error_free_subvol_name:
+ kfree(subvol_name);
+ return error;
+}
+
+static int btrfs_remount(struct super_block *sb, int *flags, char *data)
+{
+ struct btrfs_root *root = btrfs_sb(sb);
+ int ret;
+
+ if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
+ return 0;
+
+ if (*flags & MS_RDONLY) {
+ sb->s_flags |= MS_RDONLY;
+
+ ret = btrfs_commit_super(root);
+ WARN_ON(ret);
+ } else {
+ if (root->fs_info->fs_devices->rw_devices == 0)
+ return -EACCES;
+
+ if (btrfs_super_log_root(&root->fs_info->super_copy) != 0)
+ return -EINVAL;
+
+ ret = btrfs_cleanup_reloc_trees(root);
+ WARN_ON(ret);
+
+ ret = btrfs_cleanup_fs_roots(root->fs_info);
+ WARN_ON(ret);
+
+ sb->s_flags &= ~MS_RDONLY;
+ }
+
+ return 0;
+}
+
+static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+ struct btrfs_root *root = btrfs_sb(dentry->d_sb);
+ struct btrfs_super_block *disk_super = &root->fs_info->super_copy;
+ int bits = dentry->d_sb->s_blocksize_bits;
+ __be32 *fsid = (__be32 *)root->fs_info->fsid;
+
+ buf->f_namelen = BTRFS_NAME_LEN;
+ buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits;
+ buf->f_bfree = buf->f_blocks -
+ (btrfs_super_bytes_used(disk_super) >> bits);
+ buf->f_bavail = buf->f_bfree;
+ buf->f_bsize = dentry->d_sb->s_blocksize;
+ buf->f_type = BTRFS_SUPER_MAGIC;
+
+ /* We treat it as constant endianness (it doesn't matter _which_)
+ because we want the fsid to come out the same whether mounted
+ on a big-endian or little-endian host */
+ buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
+ buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
+ /* Mask in the root object ID too, to disambiguate subvols */
+ buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32;
+ buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid;
+
+ return 0;
+}
+
+static struct file_system_type btrfs_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "btrfs",
+ .get_sb = btrfs_get_sb,
+ .kill_sb = kill_anon_super,
+ .fs_flags = FS_REQUIRES_DEV,
+};
+
+/*
+ * used by btrfsctl to scan devices when no FS is mounted
+ */
+static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ struct btrfs_ioctl_vol_args *vol;
+ struct btrfs_fs_devices *fs_devices;
+ int ret = 0;
+ int len;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ vol = kmalloc(sizeof(*vol), GFP_KERNEL);
+ if (copy_from_user(vol, (void __user *)arg, sizeof(*vol))) {
+ ret = -EFAULT;
+ goto out;
+ }
+ len = strnlen(vol->name, BTRFS_PATH_NAME_MAX);
+ switch (cmd) {
+ case BTRFS_IOC_SCAN_DEV:
+ ret = btrfs_scan_one_device(vol->name, FMODE_READ,
+ &btrfs_fs_type, &fs_devices);
+ break;
+ }
+out:
+ kfree(vol);
+ return ret;
+}
+
+static void btrfs_write_super_lockfs(struct super_block *sb)
+{
+ struct btrfs_root *root = btrfs_sb(sb);
+ mutex_lock(&root->fs_info->transaction_kthread_mutex);
+ mutex_lock(&root->fs_info->cleaner_mutex);
+}
+
+static void btrfs_unlockfs(struct super_block *sb)
+{
+ struct btrfs_root *root = btrfs_sb(sb);
+ mutex_unlock(&root->fs_info->cleaner_mutex);
+ mutex_unlock(&root->fs_info->transaction_kthread_mutex);
+}
+
+static struct super_operations btrfs_super_ops = {
+ .delete_inode = btrfs_delete_inode,
+ .put_super = btrfs_put_super,
+ .write_super = btrfs_write_super,
+ .sync_fs = btrfs_sync_fs,
+ .show_options = generic_show_options,
+ .write_inode = btrfs_write_inode,
+ .dirty_inode = btrfs_dirty_inode,
+ .alloc_inode = btrfs_alloc_inode,
+ .destroy_inode = btrfs_destroy_inode,
+ .statfs = btrfs_statfs,
+ .remount_fs = btrfs_remount,
+ .write_super_lockfs = btrfs_write_super_lockfs,
+ .unlockfs = btrfs_unlockfs,
+};
+
+static const struct file_operations btrfs_ctl_fops = {
+ .unlocked_ioctl = btrfs_control_ioctl,
+ .compat_ioctl = btrfs_control_ioctl,
+ .owner = THIS_MODULE,
+};
+
+static struct miscdevice btrfs_misc = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "btrfs-control",
+ .fops = &btrfs_ctl_fops
+};
+
+static int btrfs_interface_init(void)
+{
+ return misc_register(&btrfs_misc);
+}
+
+static void btrfs_interface_exit(void)
+{
+ if (misc_deregister(&btrfs_misc) < 0)
+ printk(KERN_INFO "misc_deregister failed for control device");
+}
+
+static int __init init_btrfs_fs(void)
+{
+ int err;
+
+ err = btrfs_init_sysfs();
+ if (err)
+ return err;
+
+ err = btrfs_init_cachep();
+ if (err)
+ goto free_sysfs;
+
+ err = extent_io_init();
+ if (err)
+ goto free_cachep;
+
+ err = extent_map_init();
+ if (err)
+ goto free_extent_io;
+
+ err = btrfs_interface_init();
+ if (err)
+ goto free_extent_map;
+
+ err = register_filesystem(&btrfs_fs_type);
+ if (err)
+ goto unregister_ioctl;
+
+ printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION);
+ return 0;
+
+unregister_ioctl:
+ btrfs_interface_exit();
+free_extent_map:
+ extent_map_exit();
+free_extent_io:
+ extent_io_exit();
+free_cachep:
+ btrfs_destroy_cachep();
+free_sysfs:
+ btrfs_exit_sysfs();
+ return err;
+}
+
+static void __exit exit_btrfs_fs(void)
+{
+ btrfs_destroy_cachep();
+ extent_map_exit();
+ extent_io_exit();
+ btrfs_interface_exit();
+ unregister_filesystem(&btrfs_fs_type);
+ btrfs_exit_sysfs();
+ btrfs_cleanup_fs_uuids();
+ btrfs_zlib_exit();
+}
+
+module_init(init_btrfs_fs)
+module_exit(exit_btrfs_fs)
+
+MODULE_LICENSE("GPL");
--
1.6.0.2
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