/* * 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 "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 const char *btrfs_decode_error(struct btrfs_fs_info *fs_info, int errno, char nbuf[16]) { char *errstr = NULL; switch (errno) { case -EIO: errstr = "IO failure"; break; case -ENOMEM: errstr = "Out of memory"; break; case -EROFS: errstr = "Readonly filesystem"; break; default: if (nbuf) { if (snprintf(nbuf, 16, "error %d", -errno) >= 0) errstr = nbuf; } break; } return errstr; } static void __save_error_info(struct btrfs_fs_info *fs_info) { /* * today we only save the error info into ram. Long term we'll * also send it down to the disk */ fs_info->fs_state = BTRFS_SUPER_FLAG_ERROR; } /* NOTE: * We move write_super stuff at umount in order to avoid deadlock * for umount hold all lock. */ static void save_error_info(struct btrfs_fs_info *fs_info) { __save_error_info(fs_info); } /* btrfs handle error by forcing the filesystem readonly */ static void btrfs_handle_error(struct btrfs_fs_info *fs_info) { struct super_block *sb = fs_info->sb; if (sb->s_flags & MS_RDONLY) return; if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) { sb->s_flags |= MS_RDONLY; printk(KERN_INFO "btrfs is forced readonly\n"); } } /* * __btrfs_std_error decodes expected errors from the caller and * invokes the approciate error response. */ void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function, unsigned int line, int errno) { struct super_block *sb = fs_info->sb; char nbuf[16]; const char *errstr; /* * Special case: if the error is EROFS, and we're already * under MS_RDONLY, then it is safe here. */ if (errno == -EROFS && (sb->s_flags & MS_RDONLY)) return; errstr = btrfs_decode_error(fs_info, errno, nbuf); printk(KERN_CRIT "BTRFS error (device %s) in %s:%d: %s\n", sb->s_id, function, line, errstr); save_error_info(fs_info); btrfs_handle_error(fs_info); } static void btrfs_put_super(struct super_block *sb) { struct btrfs_root *root = btrfs_sb(sb); int ret; ret = close_ctree(root); sb->s_fs_info = NULL; (void)ret; /* FIXME: need to fix VFS to return error? */ } enum { Opt_degraded, Opt_subvol, Opt_subvolid, Opt_device, Opt_nodatasum, Opt_nodatacow, Opt_max_inline, Opt_alloc_start, Opt_nobarrier, Opt_ssd, Opt_nossd, Opt_ssd_spread, Opt_thread_pool, Opt_noacl, Opt_compress, Opt_compress_type, Opt_compress_force, Opt_compress_force_type, Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard, Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed, Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_inode_cache, Opt_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_err, NULL}, }; /* * Regular mount options parser. Everything that is needed only when * reading in a new superblock is parsed here. */ int btrfs_parse_options(struct btrfs_root *root, char *options) { struct btrfs_fs_info *info = root->fs_info; substring_t args[MAX_OPT_ARGS]; char *p, *num, *orig; int intarg; int ret = 0; char *compress_type; bool compress_force = false; 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; 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: printk(KERN_INFO "btrfs: enabling disk space caching\n"); btrfs_set_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_err: printk(KERN_INFO "btrfs: unrecognized mount option " "'%s'\n", p); ret = -EINVAL; goto out; default: break; } } out: 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 *opts, *orig, *p; int error = 0; int intarg; 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; orig = opts; while ((p = strsep(&opts, ",")) != NULL) { int token; if (!*p) continue; token = match_token(p, tokens, args); switch (token) { case Opt_subvol: *subvol_name = match_strdup(&args[0]); break; case Opt_subvolid: intarg = 0; error = match_int(&args[0], &intarg); if (!error) { /* we want the original fs_tree */ if (!intarg) *subvol_objectid = BTRFS_FS_TREE_OBJECTID; else *subvol_objectid = intarg; } break; case Opt_subvolrootid: intarg = 0; error = match_int(&args[0], &intarg); if (!error) { /* we want the original fs_tree */ if (!intarg) *subvol_rootid = BTRFS_FS_TREE_OBJECTID; else *subvol_rootid = intarg; } break; case Opt_device: 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(orig); 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 struct dentry *get_default_root(struct super_block *sb, u64 subvol_objectid) { struct btrfs_root *root = sb->s_fs_info; struct btrfs_root *new_root; struct btrfs_dir_item *di; struct btrfs_path *path; struct btrfs_key location; struct inode *inode; struct dentry *dentry; u64 dir_id; int new = 0; /* * We have a specific subvol we want to mount, just setup location and * go look up the root. */ if (subvol_objectid) { location.objectid = subvol_objectid; location.type = BTRFS_ROOT_ITEM_KEY; location.offset = (u64)-1; goto find_root; } path = btrfs_alloc_path(); if (!path) return ERR_PTR(-ENOMEM); path->leave_spinning = 1; /* * Find the "default" dir item which points to the root item that we * will mount by default if we haven't been given a specific subvolume * to mount. */ dir_id = btrfs_super_root_dir(&root->fs_info->super_copy); di = btrfs_lookup_dir_item(NULL, root, path, dir_id, "default", 7, 0); if (IS_ERR(di)) { btrfs_free_path(path); return ERR_CAST(di); } if (!di) { /* * Ok the default dir item isn't there. This is weird since * it's always been there, but don't freak out, just try and * mount to root most subvolume. */ btrfs_free_path(path); dir_id = BTRFS_FIRST_FREE_OBJECTID; new_root = root->fs_info->fs_root; goto setup_root; } btrfs_dir_item_key_to_cpu(path->nodes[0], di, &location); btrfs_free_path(path); find_root: new_root = btrfs_read_fs_root_no_name(root->fs_info, &location); if (IS_ERR(new_root)) return ERR_CAST(new_root); if (btrfs_root_refs(&new_root->root_item) == 0) return ERR_PTR(-ENOENT); dir_id = btrfs_root_dirid(&new_root->root_item); setup_root: location.objectid = dir_id; location.type = BTRFS_INODE_ITEM_KEY; location.offset = 0; inode = btrfs_iget(sb, &location, new_root, &new); if (IS_ERR(inode)) return ERR_CAST(inode); /* * If we're just mounting the root most subvol put the inode and return * a reference to the dentry. We will have already gotten a reference * to the inode in btrfs_fill_super so we're good to go. */ if (!new && sb->s_root->d_inode == inode) { iput(inode); return dget(sb->s_root); } if (new) { const struct qstr name = { .name = "/", .len = 1 }; /* * New inode, we need to make the dentry a sibling of s_root so * everything gets cleaned up properly on unmount. */ dentry = d_alloc(sb->s_root, &name); if (!dentry) { iput(inode); return ERR_PTR(-ENOMEM); } d_splice_alias(inode, dentry); } else { /* * We found the inode in cache, just find a dentry for it and * put the reference to the inode we just got. */ dentry = d_find_alias(inode); iput(inode); } return dentry; } static int btrfs_fill_super(struct super_block *sb, struct btrfs_fs_devices *fs_devices, void *data, int silent) { struct inode *inode; struct dentry *root_dentry; struct btrfs_root *tree_root; struct btrfs_key key; int err; sb->s_maxbytes = MAX_LFS_FILESIZE; sb->s_magic = BTRFS_SUPER_MAGIC; sb->s_op = &btrfs_super_ops; sb->s_d_op = &btrfs_dentry_operations; sb->s_export_op = &btrfs_export_ops; sb->s_xattr = btrfs_xattr_handlers; sb->s_time_gran = 1; #ifdef CONFIG_BTRFS_FS_POSIX_ACL sb->s_flags |= MS_POSIXACL; #endif tree_root = open_ctree(sb, fs_devices, (char *)data); if (IS_ERR(tree_root)) { printk("btrfs: open_ctree failed\n"); return PTR_ERR(tree_root); } sb->s_fs_info = tree_root; key.objectid = BTRFS_FIRST_FREE_OBJECTID; key.type = BTRFS_INODE_ITEM_KEY; key.offset = 0; inode = btrfs_iget(sb, &key, tree_root->fs_info->fs_root, NULL); if (IS_ERR(inode)) { err = PTR_ERR(inode); goto fail_close; } root_dentry = d_alloc_root(inode); if (!root_dentry) { iput(inode); err = -ENOMEM; goto fail_close; } sb->s_root = root_dentry; save_mount_options(sb, data); cleancache_init_fs(sb); return 0; fail_close: close_ctree(tree_root); return err; } int btrfs_sync_fs(struct super_block *sb, int wait) { struct btrfs_trans_handle *trans; struct btrfs_root *root = btrfs_sb(sb); int ret; trace_btrfs_sync_fs(wait); if (!wait) { filemap_flush(root->fs_info->btree_inode->i_mapping); return 0; } btrfs_start_delalloc_inodes(root, 0); btrfs_wait_ordered_extents(root, 0, 0); trans = btrfs_start_transaction(root, 0); if (IS_ERR(trans)) return PTR_ERR(trans); ret = btrfs_commit_transaction(trans, root); return ret; } static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs) { struct btrfs_root *root = btrfs_sb(vfs->mnt_sb); struct btrfs_fs_info *info = root->fs_info; char *compress_type; if (btrfs_test_opt(root, DEGRADED)) seq_puts(seq, ",degraded"); if (btrfs_test_opt(root, NODATASUM)) seq_puts(seq, ",nodatasum"); if (btrfs_test_opt(root, NODATACOW)) seq_puts(seq, ",nodatacow"); if (btrfs_test_opt(root, NOBARRIER)) seq_puts(seq, ",nobarrier"); if (info->max_inline != 8192 * 1024) seq_printf(seq, ",max_inline=%llu", (unsigned long long)info->max_inline); if (info->alloc_start != 0) seq_printf(seq, ",alloc_start=%llu", (unsigned long long)info->alloc_start); if (info->thread_pool_size != min_t(unsigned long, num_online_cpus() + 2, 8)) seq_printf(seq, ",thread_pool=%d", info->thread_pool_size); if (btrfs_test_opt(root, COMPRESS)) { if (info->compress_type == BTRFS_COMPRESS_ZLIB) compress_type = "zlib"; else compress_type = "lzo"; if (btrfs_test_opt(root, FORCE_COMPRESS)) seq_printf(seq, ",compress-force=%s", compress_type); else seq_printf(seq, ",compress=%s", compress_type); } if (btrfs_test_opt(root, NOSSD)) seq_puts(seq, ",nossd"); if (btrfs_test_opt(root, SSD_SPREAD)) seq_puts(seq, ",ssd_spread"); else if (btrfs_test_opt(root, SSD)) seq_puts(seq, ",ssd"); if (btrfs_test_opt(root, NOTREELOG)) seq_puts(seq, ",notreelog"); if (btrfs_test_opt(root, FLUSHONCOMMIT)) seq_puts(seq, ",flushoncommit"); if (btrfs_test_opt(root, DISCARD)) seq_puts(seq, ",discard"); if (!(root->fs_info->sb->s_flags & MS_POSIXACL)) seq_puts(seq, ",noacl"); if (btrfs_test_opt(root, SPACE_CACHE)) seq_puts(seq, ",space_cache"); if (btrfs_test_opt(root, CLEAR_CACHE)) seq_puts(seq, ",clear_cache"); if (btrfs_test_opt(root, USER_SUBVOL_RM_ALLOWED)) seq_puts(seq, ",user_subvol_rm_allowed"); if (btrfs_test_opt(root, ENOSPC_DEBUG)) seq_puts(seq, ",enospc_debug"); if (btrfs_test_opt(root, AUTO_DEFRAG)) seq_puts(seq, ",autodefrag"); if (btrfs_test_opt(root, INODE_MAP_CACHE)) seq_puts(seq, ",inode_cache"); return 0; } static int btrfs_test_super(struct super_block *s, void *data) { struct btrfs_root *test_root = data; struct btrfs_root *root = btrfs_sb(s); /* * If this super block is going away, return false as it * can't match as an existing super block. */ if (!atomic_read(&s->s_active)) return 0; return root->fs_info->fs_devices == test_root->fs_info->fs_devices; } static int btrfs_set_super(struct super_block *s, void *data) { s->s_fs_info = data; return set_anon_super(s, data); } /* * Find a superblock for the given device / mount point. * * Note: This is based on get_sb_bdev from fs/super.c with a few additions * for multiple device setup. Make sure to keep it in sync. */ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags, const char *device_name, void *data) { struct block_device *bdev = NULL; struct super_block *s; struct dentry *root; struct btrfs_fs_devices *fs_devices = NULL; struct btrfs_root *tree_root = NULL; struct btrfs_fs_info *fs_info = NULL; fmode_t mode = FMODE_READ; char *subvol_name = NULL; u64 subvol_objectid = 0; u64 subvol_rootid = 0; int error = 0; if (!(flags & MS_RDONLY)) mode |= FMODE_WRITE; error = btrfs_parse_early_options(data, mode, fs_type, &subvol_name, &subvol_objectid, &subvol_rootid, &fs_devices); if (error) return ERR_PTR(error); error = btrfs_scan_one_device(device_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; } /* * Setup a dummy root and fs_info for test/set super. This is because * we don't actually fill this stuff out until open_ctree, but we need * it for searching for existing supers, so this lets us do that and * then open_ctree will properly initialize everything later. */ fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS); tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS); if (!fs_info || !tree_root) { error = -ENOMEM; goto error_close_devices; } fs_info->tree_root = tree_root; fs_info->fs_devices = fs_devices; tree_root->fs_info = fs_info; bdev = fs_devices->latest_bdev; s = sget(fs_type, btrfs_test_super, btrfs_set_super, tree_root); if (IS_ERR(s)) goto error_s; if (s->s_root) { if ((flags ^ s->s_flags) & MS_RDONLY) { deactivate_locked_super(s); error = -EBUSY; goto error_close_devices; } btrfs_close_devices(fs_devices); kfree(fs_info); kfree(tree_root); } else { char b[BDEVNAME_SIZE]; s->s_flags = flags | MS_NOSEC; strlcpy(s->s_id, bdevname(bdev, b), sizeof(s->s_id)); error = btrfs_fill_super(s, fs_devices, data, flags & MS_SILENT ? 1 : 0); if (error) { deactivate_locked_super(s); goto error_free_subvol_name; } btrfs_sb(s)->fs_info->bdev_holder = fs_type; s->s_flags |= MS_ACTIVE; } /* if they gave us a subvolume name bind mount into that */ if (strcmp(subvol_name, ".")) { struct dentry *new_root; root = get_default_root(s, subvol_rootid); if (IS_ERR(root)) { error = PTR_ERR(root); deactivate_locked_super(s); goto error_free_subvol_name; } mutex_lock(&root->d_inode->i_mutex); new_root = lookup_one_len(subvol_name, root, strlen(subvol_name)); mutex_unlock(&root->d_inode->i_mutex); if (IS_ERR(new_root)) { dput(root); deactivate_locked_super(s); error = PTR_ERR(new_root); goto error_free_subvol_name; } if (!new_root->d_inode) { dput(root); dput(new_root); deactivate_locked_super(s); error = -ENXIO; goto error_free_subvol_name; } dput(root); root = new_root; } else { root = get_default_root(s, subvol_objectid); if (IS_ERR(root)) { error = PTR_ERR(root); deactivate_locked_super(s); goto error_free_subvol_name; } } kfree(subvol_name); return root; error_s: error = PTR_ERR(s); error_close_devices: btrfs_close_devices(fs_devices); kfree(fs_info); kfree(tree_root); error_free_subvol_name: kfree(subvol_name); return ERR_PTR(error); } static int btrfs_remount(struct super_block *sb, int *flags, char *data) { struct btrfs_root *root = btrfs_sb(sb); int ret; ret = btrfs_parse_options(root, data); if (ret) return -EINVAL; if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) return 0; if (*flags & MS_RDONLY) { sb->s_flags |= MS_RDONLY; ret = btrfs_commit_super(root); WARN_ON(ret); } else { if (root->fs_info->fs_devices->rw_devices == 0) return -EACCES; if (btrfs_super_log_root(&root->fs_info->super_copy) != 0) return -EINVAL; ret = btrfs_cleanup_fs_roots(root->fs_info); WARN_ON(ret); /* recover relocation */ ret = btrfs_recover_relocation(root); WARN_ON(ret); sb->s_flags &= ~MS_RDONLY; } return 0; } /* Used to sort the devices by max_avail(descending sort) */ static int btrfs_cmp_device_free_bytes(const void *dev_info1, const void *dev_info2) { if (((struct btrfs_device_info *)dev_info1)->max_avail > ((struct btrfs_device_info *)dev_info2)->max_avail) return -1; else if (((struct btrfs_device_info *)dev_info1)->max_avail < ((struct btrfs_device_info *)dev_info2)->max_avail) return 1; else return 0; } /* * sort the devices by max_avail, in which max free extent size of each device * is stored.(Descending Sort) */ static inline void btrfs_descending_sort_devices( struct btrfs_device_info *devices, size_t nr_devices) { sort(devices, nr_devices, sizeof(struct btrfs_device_info), btrfs_cmp_device_free_bytes, NULL); } /* * The helper to calc the free space on the devices that can be used to store * file data. */ static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes) { struct btrfs_fs_info *fs_info = root->fs_info; struct btrfs_device_info *devices_info; struct btrfs_fs_devices *fs_devices = fs_info->fs_devices; struct btrfs_device *device; u64 skip_space; u64 type; u64 avail_space; u64 used_space; u64 min_stripe_size; int min_stripes = 1; int i = 0, nr_devices; int ret; nr_devices = fs_info->fs_devices->rw_devices; BUG_ON(!nr_devices); devices_info = kmalloc(sizeof(*devices_info) * nr_devices, GFP_NOFS); if (!devices_info) return -ENOMEM; /* calc min stripe number for data space alloction */ type = btrfs_get_alloc_profile(root, 1); if (type & BTRFS_BLOCK_GROUP_RAID0) min_stripes = 2; else if (type & BTRFS_BLOCK_GROUP_RAID1) min_stripes = 2; else if (type & BTRFS_BLOCK_GROUP_RAID10) min_stripes = 4; if (type & BTRFS_BLOCK_GROUP_DUP) min_stripe_size = 2 * BTRFS_STRIPE_LEN; else min_stripe_size = BTRFS_STRIPE_LEN; list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) { if (!device->in_fs_metadata) continue; avail_space = device->total_bytes - device->bytes_used; /* align with stripe_len */ do_div(avail_space, BTRFS_STRIPE_LEN); avail_space *= BTRFS_STRIPE_LEN; /* * In order to avoid overwritting the superblock on the drive, * btrfs starts at an offset of at least 1MB when doing chunk * allocation. */ skip_space = 1024 * 1024; /* user can set the offset in fs_info->alloc_start. */ if (fs_info->alloc_start + BTRFS_STRIPE_LEN <= device->total_bytes) skip_space = max(fs_info->alloc_start, skip_space); /* * btrfs can not use the free space in [0, skip_space - 1], * we must subtract it from the total. In order to implement * it, we account the used space in this range first. */ ret = btrfs_account_dev_extents_size(device, 0, skip_space - 1, &used_space); if (ret) { kfree(devices_info); return ret; } /* calc the free space in [0, skip_space - 1] */ skip_space -= used_space; /* * we can use the free space in [0, skip_space - 1], subtract * it from the total. */ if (avail_space && avail_space >= skip_space) avail_space -= skip_space; else avail_space = 0; if (avail_space < min_stripe_size) continue; devices_info[i].dev = device; devices_info[i].max_avail = avail_space; i++; } nr_devices = i; btrfs_descending_sort_devices(devices_info, nr_devices); i = nr_devices - 1; avail_space = 0; while (nr_devices >= min_stripes) { if (devices_info[i].max_avail >= min_stripe_size) { int j; u64 alloc_size; avail_space += devices_info[i].max_avail * min_stripes; alloc_size = devices_info[i].max_avail; for (j = i + 1 - min_stripes; j <= i; j++) devices_info[j].max_avail -= alloc_size; } i--; nr_devices--; } kfree(devices_info); *free_bytes = avail_space; return 0; } static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf) { struct btrfs_root *root = btrfs_sb(dentry->d_sb); struct btrfs_super_block *disk_super = &root->fs_info->super_copy; struct list_head *head = &root->fs_info->space_info; struct btrfs_space_info *found; u64 total_used = 0; u64 total_free_data = 0; int bits = dentry->d_sb->s_blocksize_bits; __be32 *fsid = (__be32 *)root->fs_info->fsid; int ret; /* holding chunk_muext to avoid allocating new chunks */ mutex_lock(&root->fs_info->chunk_mutex); rcu_read_lock(); list_for_each_entry_rcu(found, head, list) { if (found->flags & BTRFS_BLOCK_GROUP_DATA) { total_free_data += found->disk_total - found->disk_used; total_free_data -= btrfs_account_ro_block_groups_free_space(found); } total_used += found->disk_used; } rcu_read_unlock(); buf->f_namelen = BTRFS_NAME_LEN; buf->f_blocks = btrfs_super_total_bytes(disk_super) >> bits; buf->f_bfree = buf->f_blocks - (total_used >> bits); buf->f_bsize = dentry->d_sb->s_blocksize; buf->f_type = BTRFS_SUPER_MAGIC; buf->f_bavail = total_free_data; ret = btrfs_calc_avail_data_space(root, &total_free_data); if (ret) { mutex_unlock(&root->fs_info->chunk_mutex); return ret; } buf->f_bavail += total_free_data; buf->f_bavail = buf->f_bavail >> bits; mutex_unlock(&root->fs_info->chunk_mutex); /* We treat it as constant endianness (it doesn't matter _which_) because we want the fsid to come out the same whether mounted on a big-endian or little-endian host */ buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]); buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]); /* Mask in the root object ID too, to disambiguate subvols */ buf->f_fsid.val[0] ^= BTRFS_I(dentry->d_inode)->root->objectid >> 32; buf->f_fsid.val[1] ^= BTRFS_I(dentry->d_inode)->root->objectid; return 0; } static struct file_system_type btrfs_fs_type = { .owner = THIS_MODULE, .name = "btrfs", .mount = btrfs_mount, .kill_sb = kill_anon_super, .fs_flags = FS_REQUIRES_DEV, }; /* * used by btrfsctl to scan devices when no FS is mounted */ static long btrfs_control_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct btrfs_ioctl_vol_args *vol; struct btrfs_fs_devices *fs_devices; int ret = -ENOTTY; if (!capable(CAP_SYS_ADMIN)) return -EPERM; vol = memdup_user((void __user *)arg, sizeof(*vol)); if (IS_ERR(vol)) return PTR_ERR(vol); switch (cmd) { case BTRFS_IOC_SCAN_DEV: ret = btrfs_scan_one_device(vol->name, FMODE_READ, &btrfs_fs_type, &fs_devices); break; } kfree(vol); return ret; } static int btrfs_freeze(struct super_block *sb) { struct btrfs_root *root = btrfs_sb(sb); mutex_lock(&root->fs_info->transaction_kthread_mutex); mutex_lock(&root->fs_info->cleaner_mutex); return 0; } static int btrfs_unfreeze(struct super_block *sb) { struct btrfs_root *root = btrfs_sb(sb); mutex_unlock(&root->fs_info->cleaner_mutex); mutex_unlock(&root->fs_info->transaction_kthread_mutex); return 0; } static const struct super_operations btrfs_super_ops = { .drop_inode = btrfs_drop_inode, .evict_inode = btrfs_evict_inode, .put_super = btrfs_put_super, .sync_fs = btrfs_sync_fs, .show_options = btrfs_show_options, .write_inode = btrfs_write_inode, .dirty_inode = btrfs_dirty_inode, .alloc_inode = btrfs_alloc_inode, .destroy_inode = btrfs_destroy_inode, .statfs = btrfs_statfs, .remount_fs = btrfs_remount, .freeze_fs = btrfs_freeze, .unfreeze_fs = btrfs_unfreeze, }; static const struct file_operations btrfs_ctl_fops = { .unlocked_ioctl = btrfs_control_ioctl, .compat_ioctl = btrfs_control_ioctl, .owner = THIS_MODULE, .llseek = noop_llseek, }; static struct miscdevice btrfs_misc = { .minor = BTRFS_MINOR, .name = "btrfs-control", .fops = &btrfs_ctl_fops }; MODULE_ALIAS_MISCDEV(BTRFS_MINOR); MODULE_ALIAS("devname:btrfs-control"); static int btrfs_interface_init(void) { return misc_register(&btrfs_misc); } static void btrfs_interface_exit(void) { if (misc_deregister(&btrfs_misc) < 0) printk(KERN_INFO "misc_deregister failed for control device"); } static int __init init_btrfs_fs(void) { int err; err = btrfs_init_sysfs(); if (err) return err; err = btrfs_init_compress(); if (err) goto free_sysfs; err = btrfs_init_cachep(); if (err) goto free_compress; err = extent_io_init(); if (err) goto free_cachep; err = extent_map_init(); if (err) goto free_extent_io; err = btrfs_delayed_inode_init(); if (err) goto free_extent_map; err = btrfs_interface_init(); if (err) goto free_delayed_inode; err = register_filesystem(&btrfs_fs_type); if (err) goto unregister_ioctl; printk(KERN_INFO "%s loaded\n", BTRFS_BUILD_VERSION); return 0; unregister_ioctl: btrfs_interface_exit(); free_delayed_inode: btrfs_delayed_inode_exit(); free_extent_map: extent_map_exit(); free_extent_io: extent_io_exit(); free_cachep: btrfs_destroy_cachep(); free_compress: btrfs_exit_compress(); free_sysfs: btrfs_exit_sysfs(); return err; } static void __exit exit_btrfs_fs(void) { btrfs_destroy_cachep(); btrfs_delayed_inode_exit(); extent_map_exit(); extent_io_exit(); btrfs_interface_exit(); unregister_filesystem(&btrfs_fs_type); btrfs_exit_sysfs(); btrfs_cleanup_fs_uuids(); btrfs_exit_compress(); } module_init(init_btrfs_fs) module_exit(exit_btrfs_fs) MODULE_LICENSE("GPL");