Btrfs fixes and enhancements.

fs/btrfs/ctree.c

@@ -1011,7 +1011,7 @@ static noinline int update_ref_for_cow(struct btrfs_trans_handle *trans,
 			return ret;
 		if (refs == 0) {
 			ret = -EROFS;
-			btrfs_std_error(root->fs_info, ret);
+			btrfs_std_error(root->fs_info, ret, NULL);
 			return ret;
 		}
 	} else {
@@ -1927,7 +1927,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 		child = read_node_slot(root, mid, 0);
 		if (!child) {
 			ret = -EROFS;
-			btrfs_std_error(root->fs_info, ret);
+			btrfs_std_error(root->fs_info, ret, NULL);
 			goto enospc;
 		}
 
@@ -2030,7 +2030,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
 		 */
 		if (!left) {
 			ret = -EROFS;
-			btrfs_std_error(root->fs_info, ret);
+			btrfs_std_error(root->fs_info, ret, NULL);
 			goto enospc;
 		}
 		wret = balance_node_right(trans, root, mid, left);

fs/btrfs/ctree.h

@@ -4004,8 +4004,8 @@ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
 /* sysfs.c */
 int btrfs_init_sysfs(void);
 void btrfs_exit_sysfs(void);
-int btrfs_sysfs_add_one(struct btrfs_fs_info *fs_info);
-void btrfs_sysfs_remove_one(struct btrfs_fs_info *fs_info);
+int btrfs_sysfs_add_mounted(struct btrfs_fs_info *fs_info);
+void btrfs_sysfs_remove_mounted(struct btrfs_fs_info *fs_info);
 
 /* xattr.c */
 ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size);
@@ -4127,14 +4127,7 @@ do {								\
 				  __LINE__, (errno));		\
 } while (0)
 
-#define btrfs_std_error(fs_info, errno)				\
-do {								\
-	if ((errno))						\
-		__btrfs_std_error((fs_info), __func__,		\
-				   __LINE__, (errno), NULL);	\
-} while (0)
-
-#define btrfs_error(fs_info, errno, fmt, args...)		\
+#define btrfs_std_error(fs_info, errno, fmt, args...)		\
 do {								\
 	__btrfs_std_error((fs_info), __func__, __LINE__,	\
 			  (errno), fmt, ##args);		\

fs/btrfs/dev-replace.c

@@ -44,9 +44,6 @@ static void btrfs_dev_replace_update_device_in_mapping_tree(
 						struct btrfs_fs_info *fs_info,
 						struct btrfs_device *srcdev,
 						struct btrfs_device *tgtdev);
-static int btrfs_dev_replace_find_srcdev(struct btrfs_root *root, u64 srcdevid,
-					 char *srcdev_name,
-					 struct btrfs_device **device);
 static u64 __btrfs_dev_replace_cancel(struct btrfs_fs_info *fs_info);
 static int btrfs_dev_replace_kthread(void *data);
 static int btrfs_dev_replace_continue_on_mount(struct btrfs_fs_info *fs_info);
@@ -323,26 +320,9 @@ int btrfs_dev_replace_start(struct btrfs_root *root,
 		return -EINVAL;
 	}
 
-	if ((args->start.srcdevid == 0 && args->start.srcdev_name[0] == '\0') ||
-	    args->start.tgtdev_name[0] == '\0')
-		return -EINVAL;
-
-	/*
-	 * Here we commit the transaction to make sure commit_total_bytes
-	 * of all the devices are updated.
-	 */
-	trans = btrfs_attach_transaction(root);
-	if (!IS_ERR(trans)) {
-		ret = btrfs_commit_transaction(trans, root);
-		if (ret)
-			return ret;
-	} else if (PTR_ERR(trans) != -ENOENT) {
-		return PTR_ERR(trans);
-	}
-
 	/* the disk copy procedure reuses the scrub code */
 	mutex_lock(&fs_info->volume_mutex);
-	ret = btrfs_dev_replace_find_srcdev(root, args->start.srcdevid,
+	ret = btrfs_find_device_by_user_input(root, args->start.srcdevid,
 					    args->start.srcdev_name,
 					    &src_device);
 	if (ret) {
@@ -356,6 +336,19 @@ int btrfs_dev_replace_start(struct btrfs_root *root,
 	if (ret)
 		return ret;
 
+	/*
+	 * Here we commit the transaction to make sure commit_total_bytes
+	 * of all the devices are updated.
+	 */
+	trans = btrfs_attach_transaction(root);
+	if (!IS_ERR(trans)) {
+		ret = btrfs_commit_transaction(trans, root);
+		if (ret)
+			return ret;
+	} else if (PTR_ERR(trans) != -ENOENT) {
+		return PTR_ERR(trans);
+	}
+
 	btrfs_dev_replace_lock(dev_replace);
 	switch (dev_replace->replace_state) {
 	case BTRFS_IOCTL_DEV_REPLACE_STATE_NEVER_STARTED:
@@ -375,10 +368,6 @@ int btrfs_dev_replace_start(struct btrfs_root *root,
 	WARN_ON(!tgt_device);
 	dev_replace->tgtdev = tgt_device;
 
-	ret = btrfs_kobj_add_device(tgt_device->fs_devices, tgt_device);
-	if (ret)
-		btrfs_err(root->fs_info, "kobj add dev failed %d\n", ret);
-
 	printk_in_rcu(KERN_INFO
 		      "BTRFS: dev_replace from %s (devid %llu) to %s started\n",
 		      src_device->missing ? "<missing disk>" :
@@ -401,6 +390,14 @@ int btrfs_dev_replace_start(struct btrfs_root *root,
 	args->result = BTRFS_IOCTL_DEV_REPLACE_RESULT_NO_ERROR;
 	btrfs_dev_replace_unlock(dev_replace);
 
+	ret = btrfs_sysfs_add_device_link(tgt_device->fs_devices, tgt_device, 0);
+	if (ret)
+		btrfs_err(root->fs_info, "kobj add dev failed %d\n", ret);
+
+	ret = btrfs_sysfs_add_device_attr(tgt_device);
+	if (ret && ret != -EEXIST)
+		btrfs_err(root->fs_info, "sysfs create dev failed %d\n", ret);
+
 	btrfs_wait_ordered_roots(root->fs_info, -1);
 
 	/* force writing the updated state information to disk */
@@ -586,7 +583,12 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
 	mutex_unlock(&uuid_mutex);
 
 	/* replace the sysfs entry */
-	btrfs_kobj_rm_device(fs_info->fs_devices, src_device);
+	btrfs_sysfs_rm_device_link(fs_info->fs_devices, src_device, 0);
+	if (src_device->fs_devices->seeding &&
+				!src_device->fs_devices->num_devices)
+		btrfs_sysfs_remove_fsid(src_device->fs_devices);
+	else
+		btrfs_sysfs_rm_device_attr(src_device);
 	btrfs_rm_dev_replace_free_srcdev(fs_info, src_device);
 
 	/* write back the superblocks */
@@ -625,25 +627,6 @@ static void btrfs_dev_replace_update_device_in_mapping_tree(
 	write_unlock(&em_tree->lock);
 }
 
-static int btrfs_dev_replace_find_srcdev(struct btrfs_root *root, u64 srcdevid,
-					 char *srcdev_name,
-					 struct btrfs_device **device)
-{
-	int ret;
-
-	if (srcdevid) {
-		ret = 0;
-		*device = btrfs_find_device(root->fs_info, srcdevid, NULL,
-					    NULL);
-		if (!*device)
-			ret = -ENOENT;
-	} else {
-		ret = btrfs_find_device_missing_or_by_path(root, srcdev_name,
-							   device);
-	}
-	return ret;
-}
-
 void btrfs_dev_replace_status(struct btrfs_fs_info *fs_info,
 			      struct btrfs_ioctl_dev_replace_args *args)
 {

fs/btrfs/disk-io.c

@@ -2377,7 +2377,7 @@ static int btrfs_replay_log(struct btrfs_fs_info *fs_info,
 	/* returns with log_tree_root freed on success */
 	ret = btrfs_recover_log_trees(log_tree_root);
 	if (ret) {
-		btrfs_error(tree_root->fs_info, ret,
+		btrfs_std_error(tree_root->fs_info, ret,
 			    "Failed to recover log tree");
 		free_extent_buffer(log_tree_root->node);
 		kfree(log_tree_root);
@@ -2653,8 +2653,8 @@ int open_ctree(struct super_block *sb,
 	 * Read super block and check the signature bytes only
 	 */
 	bh = btrfs_read_dev_super(fs_devices->latest_bdev);
-	if (!bh) {
-		err = -EINVAL;
+	if (IS_ERR(bh)) {
+		err = PTR_ERR(bh);
 		goto fail_alloc;
 	}
 
@@ -2665,6 +2665,7 @@ int open_ctree(struct super_block *sb,
 	if (btrfs_check_super_csum(bh->b_data)) {
 		printk(KERN_ERR "BTRFS: superblock checksum mismatch\n");
 		err = -EINVAL;
+		brelse(bh);
 		goto fail_alloc;
 	}
 
@@ -2921,22 +2922,10 @@ int open_ctree(struct super_block *sb,
 
 	btrfs_close_extra_devices(fs_devices, 1);
 
-	ret = btrfs_sysfs_add_fsid(fs_devices, NULL);
-	if (ret) {
-		pr_err("BTRFS: failed to init sysfs fsid interface: %d\n", ret);
-		goto fail_block_groups;
-	}
-
-	ret = btrfs_sysfs_add_device(fs_devices);
-	if (ret) {
-		pr_err("BTRFS: failed to init sysfs device interface: %d\n", ret);
-		goto fail_fsdev_sysfs;
-	}
-
-	ret = btrfs_sysfs_add_one(fs_info);
+	ret = btrfs_sysfs_add_mounted(fs_info);
 	if (ret) {
 		pr_err("BTRFS: failed to init sysfs interface: %d\n", ret);
-		goto fail_fsdev_sysfs;
+		goto fail_block_groups;
 	}
 
 	ret = btrfs_init_space_info(fs_info);
@@ -3113,10 +3102,7 @@ int open_ctree(struct super_block *sb,
 	filemap_write_and_wait(fs_info->btree_inode->i_mapping);
 
 fail_sysfs:
-	btrfs_sysfs_remove_one(fs_info);
-
-fail_fsdev_sysfs:
-	btrfs_sysfs_remove_fsid(fs_info->fs_devices);
+	btrfs_sysfs_remove_mounted(fs_info);
 
 fail_block_groups:
 	btrfs_put_block_group_cache(fs_info);
@@ -3188,36 +3174,57 @@ static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
 	put_bh(bh);
 }
 
+int btrfs_read_dev_one_super(struct block_device *bdev, int copy_num,
+			struct buffer_head **bh_ret)
+{
+	struct buffer_head *bh;
+	struct btrfs_super_block *super;
+	u64 bytenr;
+
+	bytenr = btrfs_sb_offset(copy_num);
+	if (bytenr + BTRFS_SUPER_INFO_SIZE >= i_size_read(bdev->bd_inode))
+		return -EINVAL;
+
+	bh = __bread(bdev, bytenr / 4096, BTRFS_SUPER_INFO_SIZE);
+	/*
+	 * If we fail to read from the underlying devices, as of now
+	 * the best option we have is to mark it EIO.
+	 */
+	if (!bh)
+		return -EIO;
+
+	super = (struct btrfs_super_block *)bh->b_data;
+	if (btrfs_super_bytenr(super) != bytenr ||
+		    btrfs_super_magic(super) != BTRFS_MAGIC) {
+		brelse(bh);
+		return -EINVAL;
+	}
+
+	*bh_ret = bh;
+	return 0;
+}
+
+
 struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
 {
 	struct buffer_head *bh;
 	struct buffer_head *latest = NULL;
 	struct btrfs_super_block *super;
 	int i;
 	u64 transid = 0;
-	u64 bytenr;
+	int ret = -EINVAL;
 
 	/* we would like to check all the supers, but that would make
 	 * a btrfs mount succeed after a mkfs from a different FS.
 	 * So, we need to add a special mount option to scan for
 	 * later supers, using BTRFS_SUPER_MIRROR_MAX instead
 	 */
 	for (i = 0; i < 1; i++) {
-		bytenr = btrfs_sb_offset(i);
-		if (bytenr + BTRFS_SUPER_INFO_SIZE >=
-					i_size_read(bdev->bd_inode))
-			break;
-		bh = __bread(bdev, bytenr / 4096,
-					BTRFS_SUPER_INFO_SIZE);
-		if (!bh)
+		ret = btrfs_read_dev_one_super(bdev, i, &bh);
+		if (ret)
 			continue;
 
 		super = (struct btrfs_super_block *)bh->b_data;
-		if (btrfs_super_bytenr(super) != bytenr ||
-		    btrfs_super_magic(super) != BTRFS_MAGIC) {
-			brelse(bh);
-			continue;
-		}
 
 		if (!latest || btrfs_super_generation(super) > transid) {
 			brelse(latest);
@@ -3227,6 +3234,10 @@ struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
 			brelse(bh);
 		}
 	}
+
+	if (!latest)
+		return ERR_PTR(ret);
+
 	return latest;
 }
 
@@ -3544,7 +3555,7 @@ static int write_all_supers(struct btrfs_root *root, int max_mirrors)
 		if (ret) {
 			mutex_unlock(
 				&root->fs_info->fs_devices->device_list_mutex);
-			btrfs_error(root->fs_info, ret,
+			btrfs_std_error(root->fs_info, ret,
 				    "errors while submitting device barriers.");
 			return ret;
 		}
@@ -3584,7 +3595,7 @@ static int write_all_supers(struct btrfs_root *root, int max_mirrors)
 		mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
 
 		/* FUA is masked off if unsupported and can't be the reason */
-		btrfs_error(root->fs_info, -EIO,
+		btrfs_std_error(root->fs_info, -EIO,
 			    "%d errors while writing supers", total_errors);
 		return -EIO;
 	}
@@ -3602,7 +3613,7 @@ static int write_all_supers(struct btrfs_root *root, int max_mirrors)
 	}
 	mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
 	if (total_errors > max_errors) {
-		btrfs_error(root->fs_info, -EIO,
+		btrfs_std_error(root->fs_info, -EIO,
 			    "%d errors while writing supers", total_errors);
 		return -EIO;
 	}
@@ -3788,8 +3799,11 @@ void close_ctree(struct btrfs_root *root)
 		       percpu_counter_sum(&fs_info->delalloc_bytes));
 	}
 
-	btrfs_sysfs_remove_one(fs_info);
-	btrfs_sysfs_remove_fsid(fs_info->fs_devices);
+	btrfs_sysfs_remove_mounted(fs_info);
+	if (fs_info->fs_devices->seed) {
+		btrfs_sysfs_remove_fsid(fs_info->fs_devices->seed);
+		btrfs_sysfs_rm_seed_dir(fs_info->fs_devices);
+	}
 
 	btrfs_free_fs_roots(fs_info);
 

fs/btrfs/disk-io.h

@@ -60,6 +60,8 @@ void close_ctree(struct btrfs_root *root);
 int write_ctree_super(struct btrfs_trans_handle *trans,
 		      struct btrfs_root *root, int max_mirrors);
 struct buffer_head *btrfs_read_dev_super(struct block_device *bdev);
+int btrfs_read_dev_one_super(struct block_device *bdev, int copy_num,
+			struct buffer_head **bh_ret);
 int btrfs_commit_super(struct btrfs_root *root);
 struct extent_buffer *btrfs_find_tree_block(struct btrfs_fs_info *fs_info,
 					    u64 bytenr);

fs/btrfs/extent-tree.c

@@ -8688,7 +8688,7 @@ int btrfs_drop_snapshot(struct btrfs_root *root,
 	if (!for_reloc && root_dropped == false)
 		btrfs_add_dead_root(root);
 	if (err && err != -EAGAIN)
-		btrfs_std_error(root->fs_info, err);
+		btrfs_std_error(root->fs_info, err, NULL);
 	return err;
 }
 

fs/btrfs/inode-item.c

@@ -157,7 +157,7 @@ static int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
 	 */
 	if (!btrfs_find_name_in_ext_backref(path, ref_objectid,
 					    name, name_len, &extref)) {
-		btrfs_std_error(root->fs_info, -ENOENT);
+		btrfs_std_error(root->fs_info, -ENOENT, NULL);
 		ret = -EROFS;
 		goto out;
 	}