Merge branch 'btrfs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

* 'btrfs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  btrfs: take allocation of ->tree_root into open_ctree()
  btrfs: let ->s_fs_info point to fs_info, not root...
  btrfs: consolidate failure exits in btrfs_mount() a bit
  btrfs: make free_fs_info() call ->kill_sb() unconditional
  btrfs: merge free_fs_info() calls on fill_super failures
  btrfs: kill pointless reassignment of ->s_fs_info in btrfs_fill_super()
  btrfs: make open_ctree() return int
  btrfs: sanitizing ->fs_info, part 5
  btrfs: sanitizing ->fs_info, part 4
  btrfs: sanitizing ->fs_info, part 3
  btrfs: sanitizing ->fs_info, part 2
  btrfs: sanitizing ->fs_info, part 1
  btrfs: fix a deadlock in btrfs_scan_one_device()
  btrfs: fix mount/umount race
  btrfs: get ->kill_sb() of its own
  btrfs: preparation to fixing mount/umount race

1 files changed, 64 insertions, 79 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 8ffaaa8e3df8..3ce97b217cbe 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -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;
 }