Merge branch 'btrfs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
[~shefty/rdma-dev.git] / fs / btrfs / super.c
index 8ffaaa8e3df80fff13a75b9d6443373624e70753..3ce97b217cbeae21ef23e57fe2a605ed11572af1 100644 (file)
@@ -147,13 +147,13 @@ void __btrfs_std_error(struct btrfs_fs_info *fs_info, const char *function,
 
 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? */
+       (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 {
@@ -541,7 +541,8 @@ out:
 static struct dentry *get_default_root(struct super_block *sb,
                                       u64 subvol_objectid)
 {
-       struct btrfs_root *root = sb->s_fs_info;
+       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;
@@ -571,7 +572,7 @@ static struct dentry *get_default_root(struct super_block *sb,
         * 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);
+       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);
@@ -585,7 +586,7 @@ static struct dentry *get_default_root(struct super_block *sb,
                 */
                btrfs_free_path(path);
                dir_id = BTRFS_FIRST_FREE_OBJECTID;
-               new_root = root->fs_info->fs_root;
+               new_root = fs_info->fs_root;
                goto setup_root;
        }
 
@@ -593,7 +594,7 @@ static struct dentry *get_default_root(struct super_block *sb,
        btrfs_free_path(path);
 
 find_root:
-       new_root = btrfs_read_fs_root_no_name(root->fs_info, &location);
+       new_root = btrfs_read_fs_root_no_name(fs_info, &location);
        if (IS_ERR(new_root))
                return ERR_CAST(new_root);
 
@@ -629,7 +630,7 @@ static int btrfs_fill_super(struct super_block *sb,
 {
        struct inode *inode;
        struct dentry *root_dentry;
-       struct btrfs_root *tree_root;
+       struct btrfs_fs_info *fs_info = btrfs_sb(sb);
        struct btrfs_key key;
        int err;
 
@@ -644,18 +645,16 @@ static int btrfs_fill_super(struct super_block *sb,
        sb->s_flags |= MS_POSIXACL;
 #endif
 
-       tree_root = open_ctree(sb, fs_devices, (char *)data);
-
-       if (IS_ERR(tree_root)) {
+       err = open_ctree(sb, fs_devices, (char *)data);
+       if (err) {
                printk("btrfs: open_ctree failed\n");
-               return PTR_ERR(tree_root);
+               return err;
        }
-       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);
+       inode = btrfs_iget(sb, &key, fs_info->fs_root, NULL);
        if (IS_ERR(inode)) {
                err = PTR_ERR(inode);
                goto fail_close;
@@ -672,23 +671,25 @@ static int btrfs_fill_super(struct super_block *sb,
 
        save_mount_options(sb, data);
        cleancache_init_fs(sb);
+       sb->s_flags |= MS_ACTIVE;
        return 0;
 
 fail_close:
-       close_ctree(tree_root);
+       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_root *root = btrfs_sb(sb);
+       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(root->fs_info->btree_inode->i_mapping);
+               filemap_flush(fs_info->btree_inode->i_mapping);
                return 0;
        }
 
@@ -704,8 +705,8 @@ int btrfs_sync_fs(struct super_block *sb, int wait)
 
 static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
 {
-       struct btrfs_root *root = btrfs_sb(dentry->d_sb);
-       struct btrfs_fs_info *info = root->fs_info;
+       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))
@@ -770,23 +771,18 @@ static int btrfs_show_options(struct seq_file *seq, struct dentry *dentry)
 
 static int btrfs_test_super(struct super_block *s, void *data)
 {
-       struct btrfs_root *test_root = data;
-       struct btrfs_root *root = btrfs_sb(s);
+       struct btrfs_fs_info *p = data;
+       struct btrfs_fs_info *fs_info = 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;
+       return fs_info->fs_devices == p->fs_devices;
 }
 
 static int btrfs_set_super(struct super_block *s, void *data)
 {
-       s->s_fs_info = data;
-
-       return set_anon_super(s, data);
+       int err = set_anon_super(s, data);
+       if (!err)
+               s->s_fs_info = data;
+       return err;
 }
 
 /*
@@ -946,12 +942,6 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
        if (!fs_info)
                return ERR_PTR(-ENOMEM);
 
-       fs_info->tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
-       if (!fs_info->tree_root) {
-               error = -ENOMEM;
-               goto error_fs_info;
-       }
-       fs_info->tree_root->fs_info = fs_info;
        fs_info->fs_devices = fs_devices;
 
        fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS);
@@ -971,43 +961,30 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags,
        }
 
        bdev = fs_devices->latest_bdev;
-       s = sget(fs_type, btrfs_test_super, btrfs_set_super,
-                fs_info->tree_root);
+       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) {
-               if ((flags ^ s->s_flags) & MS_RDONLY) {
-                       deactivate_locked_super(s);
-                       error = -EBUSY;
-                       goto error_close_devices;
-               }
-
                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)->fs_info->bdev_holder = fs_type;
+               btrfs_sb(s)->bdev_holder = fs_type;
                error = btrfs_fill_super(s, fs_devices, data,
                                         flags & MS_SILENT ? 1 : 0);
-               if (error) {
-                       deactivate_locked_super(s);
-                       return ERR_PTR(error);
-               }
-
-               s->s_flags |= MS_ACTIVE;
        }
 
-       root = get_default_root(s, subvol_objectid);
-       if (IS_ERR(root)) {
+       root = !error ? get_default_root(s, subvol_objectid) : ERR_PTR(error);
+       if (IS_ERR(root))
                deactivate_locked_super(s);
-               return root;
-       }
 
        return root;
 
@@ -1020,7 +997,8 @@ error_fs_info:
 
 static int btrfs_remount(struct super_block *sb, int *flags, char *data)
 {
-       struct btrfs_root *root = btrfs_sb(sb);
+       struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+       struct btrfs_root *root = fs_info->tree_root;
        int ret;
 
        ret = btrfs_parse_options(root, data);
@@ -1036,13 +1014,13 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data)
                ret =  btrfs_commit_super(root);
                WARN_ON(ret);
        } else {
-               if (root->fs_info->fs_devices->rw_devices == 0)
+               if (fs_info->fs_devices->rw_devices == 0)
                        return -EACCES;
 
-               if (btrfs_super_log_root(root->fs_info->super_copy) != 0)
+               if (btrfs_super_log_root(fs_info->super_copy) != 0)
                        return -EINVAL;
 
-               ret = btrfs_cleanup_fs_roots(root->fs_info);
+               ret = btrfs_cleanup_fs_roots(fs_info);
                WARN_ON(ret);
 
                /* recover relocation */
@@ -1211,18 +1189,18 @@ static int btrfs_calc_avail_data_space(struct btrfs_root *root, u64 *free_bytes)
 
 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_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 *)root->fs_info->fsid;
+       __be32 *fsid = (__be32 *)fs_info->fsid;
        int ret;
 
        /* holding chunk_muext to avoid allocating new chunks */
-       mutex_lock(&root->fs_info->chunk_mutex);
+       mutex_lock(&fs_info->chunk_mutex);
        rcu_read_lock();
        list_for_each_entry_rcu(found, head, list) {
                if (found->flags & BTRFS_BLOCK_GROUP_DATA) {
@@ -1241,14 +1219,14 @@ static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
        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);
+       ret = btrfs_calc_avail_data_space(fs_info->tree_root, &total_free_data);
        if (ret) {
-               mutex_unlock(&root->fs_info->chunk_mutex);
+               mutex_unlock(&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);
+       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
@@ -1262,11 +1240,18 @@ static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
        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        = kill_anon_super,
+       .kill_sb        = btrfs_kill_super,
        .fs_flags       = FS_REQUIRES_DEV,
 };
 
@@ -1300,17 +1285,17 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd,
 
 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);
+       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_root *root = btrfs_sb(sb);
-       mutex_unlock(&root->fs_info->cleaner_mutex);
-       mutex_unlock(&root->fs_info->transaction_kthread_mutex);
+       struct btrfs_fs_info *fs_info = btrfs_sb(sb);
+       mutex_unlock(&fs_info->cleaner_mutex);
+       mutex_unlock(&fs_info->transaction_kthread_mutex);
        return 0;
 }