[PATCH 02/25] ubifs: refactor create_default_filesystem()

[Sascha Hauer]

create_default_filesystem() allocates memory for a node, writes that
node and frees the memory directly afterwards. With this patch we
allocate memory for all nodes at the beginning of the function and
free the memory at the end. This makes it easier to implement
authentication support since with authentication support we'll need
the contents of some nodes when creating other nodes.

Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
---
 fs/ubifs/sb.c | 95 +++++++++++++++++++++++++--------------------------
 1 file changed, 47 insertions(+), 48 deletions(-)

diff --git a/fs/ubifs/sb.c b/fs/ubifs/sb.c
index bf17f58908ff..cf7ee2880c57 100644
--- a/fs/ubifs/sb.c
+++ b/fs/ubifs/sb.c
@@ -82,6 +82,7 @@ static int create_default_filesystem(struct ubifs_info *c)
 	int err, tmp, jnl_lebs, log_lebs, max_buds, main_lebs, main_first;
 	int lpt_lebs, lpt_first, orph_lebs, big_lpt, ino_waste, sup_flags = 0;
 	int min_leb_cnt = UBIFS_MIN_LEB_CNT;
+	int idx_node_size;
 	long long tmp64, main_bytes;
 	__le64 tmp_le64;
 	__le32 tmp_le32;
@@ -156,11 +157,19 @@ static int create_default_filesystem(struct ubifs_info *c)
 
 	main_first = c->leb_cnt - main_lebs;
 
+	sup = kzalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_KERNEL);
+	mst = kzalloc(c->mst_node_alsz, GFP_KERNEL);
+	idx_node_size = ubifs_idx_node_sz(c, 1);
+	idx = kzalloc(ALIGN(tmp, c->min_io_size), GFP_KERNEL);
+	ino = kzalloc(ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size), GFP_KERNEL);
+	cs = kzalloc(ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size), GFP_KERNEL);
+
+	if (!sup || !mst || !idx || !ino || !cs) {
+		err = -ENOMEM;
+		goto out;
+	}
+
 	/* Create default superblock */
-	tmp = ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size);
-	sup = kzalloc(tmp, GFP_KERNEL);
-	if (!sup)
-		return -ENOMEM;
 
 	tmp64 = (long long)max_buds * c->leb_size;
 	if (big_lpt)
@@ -197,17 +206,9 @@ static int create_default_filesystem(struct ubifs_info *c)
 	sup->rp_size = cpu_to_le64(tmp64);
 	sup->ro_compat_version = cpu_to_le32(UBIFS_RO_COMPAT_VERSION);
 
-	err = ubifs_write_node(c, sup, UBIFS_SB_NODE_SZ, 0, 0);
-	kfree(sup);
-	if (err)
-		return err;
-
 	dbg_gen("default superblock created at LEB 0:0");
 
 	/* Create default master node */
-	mst = kzalloc(c->mst_node_alsz, GFP_KERNEL);
-	if (!mst)
-		return -ENOMEM;
 
 	mst->ch.node_type = UBIFS_MST_NODE;
 	mst->log_lnum     = cpu_to_le32(UBIFS_LOG_LNUM);
@@ -253,24 +254,9 @@ static int create_default_filesystem(struct ubifs_info *c)
 
 	mst->total_used = cpu_to_le64(UBIFS_INO_NODE_SZ);
 
-	err = ubifs_write_node(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM, 0);
-	if (err) {
-		kfree(mst);
-		return err;
-	}
-	err = ubifs_write_node(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM + 1,
-			       0);
-	kfree(mst);
-	if (err)
-		return err;
-
 	dbg_gen("default master node created at LEB %d:0", UBIFS_MST_LNUM);
 
 	/* Create the root indexing node */
-	tmp = ubifs_idx_node_sz(c, 1);
-	idx = kzalloc(ALIGN(tmp, c->min_io_size), GFP_KERNEL);
-	if (!idx)
-		return -ENOMEM;
 
 	c->key_fmt = UBIFS_SIMPLE_KEY_FMT;
 	c->key_hash = key_r5_hash;
@@ -282,19 +268,11 @@ static int create_default_filesystem(struct ubifs_info *c)
 	key_write_idx(c, &key, &br->key);
 	br->lnum = cpu_to_le32(main_first + DEFAULT_DATA_LEB);
 	br->len  = cpu_to_le32(UBIFS_INO_NODE_SZ);
-	err = ubifs_write_node(c, idx, tmp, main_first + DEFAULT_IDX_LEB, 0);
-	kfree(idx);
-	if (err)
-		return err;
 
 	dbg_gen("default root indexing node created LEB %d:0",
 		main_first + DEFAULT_IDX_LEB);
 
 	/* Create default root inode */
-	tmp = ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size);
-	ino = kzalloc(tmp, GFP_KERNEL);
-	if (!ino)
-		return -ENOMEM;
 
 	ino_key_init_flash(c, &ino->key, UBIFS_ROOT_INO);
 	ino->ch.node_type = UBIFS_INO_NODE;
@@ -317,12 +295,6 @@ static int create_default_filesystem(struct ubifs_info *c)
 	/* Set compression enabled by default */
 	ino->flags = cpu_to_le32(UBIFS_COMPR_FL);
 
-	err = ubifs_write_node(c, ino, UBIFS_INO_NODE_SZ,
-			       main_first + DEFAULT_DATA_LEB, 0);
-	kfree(ino);
-	if (err)
-		return err;
-
 	dbg_gen("root inode created at LEB %d:0",
 		main_first + DEFAULT_DATA_LEB);
 
@@ -331,19 +303,46 @@ static int create_default_filesystem(struct ubifs_info *c)
 	 * always the case during normal file-system operation. Write a fake
 	 * commit start node to the log.
 	 */
-	tmp = ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size);
-	cs = kzalloc(tmp, GFP_KERNEL);
-	if (!cs)
-		return -ENOMEM;
 
 	cs->ch.node_type = UBIFS_CS_NODE;
+
+	err = ubifs_write_node(c, sup, UBIFS_SB_NODE_SZ, 0, 0);
+	if (err)
+		goto out;
+
+	err = ubifs_write_node(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM, 0);
+	if (err)
+		goto out;
+
+	err = ubifs_write_node(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM + 1,
+			       0);
+	if (err)
+		goto out;
+
+	err = ubifs_write_node(c, idx, idx_node_size, main_first + DEFAULT_IDX_LEB, 0);
+	if (err)
+		goto out;
+
+	err = ubifs_write_node(c, ino, UBIFS_INO_NODE_SZ,
+			       main_first + DEFAULT_DATA_LEB, 0);
+	if (err)
+		goto out;
+
 	err = ubifs_write_node(c, cs, UBIFS_CS_NODE_SZ, UBIFS_LOG_LNUM, 0);
-	kfree(cs);
 	if (err)
-		return err;
+		goto out;
 
 	ubifs_msg(c, "default file-system created");
-	return 0;
+
+	err = 0;
+out:
+	kfree(sup);
+	kfree(mst);
+	kfree(idx);
+	kfree(ino);
+	kfree(cs);
+
+	return err;
 }
 
 /**
-- 
2.18.0