diff options
Diffstat (limited to 'fs/btrfs/super.c')
| -rw-r--r-- | fs/btrfs/super.c | 720 |
1 files changed, 720 insertions, 0 deletions
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c new file mode 100644 index 00000000000..b4c101d9322 --- /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"); 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