ext4: start handle at the last possible moment when creating inodes

In ext4_{create,mknod,mkdir,symlink}(), don't start the journal handle
until the inode has been succesfully allocated.  In order to do this,
we need to start the handle in the ext4_new_inode().  So create a new
variant of this function, ext4_new_inode_start_handle(), so the handle
can be created at the last possible minute, before we need to modify
the inode allocation bitmap block.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/ext4.h

@@ -2004,9 +2004,20 @@ extern int ext4fs_dirhash(const char *name, int len, struct
 			  dx_hash_info *hinfo);
 
 /* ialloc.c */
-extern struct inode *ext4_new_inode(handle_t *, struct inode *, umode_t,
-				    const struct qstr *qstr, __u32 goal,
-				    uid_t *owner);
+extern struct inode *__ext4_new_inode(handle_t *, struct inode *, umode_t,
+				      const struct qstr *qstr, __u32 goal,
+				      uid_t *owner, int handle_type,
+				      unsigned int line_no, int nblocks);
+
+#define ext4_new_inode(handle, dir, mode, qstr, goal, owner) \
+	__ext4_new_inode((handle), (dir), (mode), (qstr), (goal), (owner), \
+			 0, 0, 0)
+#define ext4_new_inode_start_handle(dir, mode, qstr, goal, owner, \
+				    type, nblocks)		    \
+	__ext4_new_inode(NULL, (dir), (mode), (qstr), (goal), (owner), \
+			 (type), __LINE__, (nblocks))
+
+
 extern void ext4_free_inode(handle_t *, struct inode *);
 extern struct inode * ext4_orphan_get(struct super_block *, unsigned long);
 extern unsigned long ext4_count_free_inodes(struct super_block *);

fs/ext4/ialloc.c

@@ -634,8 +634,10 @@ static int find_group_other(struct super_block *sb, struct inode *parent,
  * For other inodes, search forward from the parent directory's block
  * group to find a free inode.
  */
-struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, umode_t mode,
-			     const struct qstr *qstr, __u32 goal, uid_t *owner)
+struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
+			       umode_t mode, const struct qstr *qstr,
+			       __u32 goal, uid_t *owner, int handle_type,
+			       unsigned int line_no, int nblocks)
 {
 	struct super_block *sb;
 	struct buffer_head *inode_bitmap_bh = NULL;
@@ -725,6 +727,15 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode *dir, umode_t mode,
 				   "inode=%lu", ino + 1);
 			continue;
 		}
+		if (!handle) {
+			BUG_ON(nblocks <= 0);
+			handle = __ext4_journal_start_sb(dir->i_sb, line_no,
+							 handle_type, nblocks);
+			if (IS_ERR(handle)) {
+				err = PTR_ERR(handle);
+				goto fail;
+			}
+		}
 		BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
 		err = ext4_journal_get_write_access(handle, inode_bitmap_bh);
 		if (err)

fs/ext4/namei.c

@@ -2257,30 +2257,28 @@ static int ext4_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 {
 	handle_t *handle;
 	struct inode *inode;
-	int err, retries = 0;
+	int err, credits, retries = 0;
 
 	dquot_initialize(dir);
 
+	credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
+		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
+		   EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb));
 retry:
-	handle = ext4_journal_start(dir, EXT4_HT_DIR,
-		(EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
-		 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
-		 EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb)));
-	if (IS_ERR(handle))
-		return PTR_ERR(handle);
-
-	if (IS_DIRSYNC(dir))
-		ext4_handle_sync(handle);
-
-	inode = ext4_new_inode(handle, dir, mode, &dentry->d_name, 0, NULL);
+	inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
+					    NULL, EXT4_HT_DIR, credits);
+	handle = ext4_journal_current_handle();
 	err = PTR_ERR(inode);
 	if (!IS_ERR(inode)) {
 		inode->i_op = &ext4_file_inode_operations;
 		inode->i_fop = &ext4_file_operations;
 		ext4_set_aops(inode);
 		err = ext4_add_nondir(handle, dentry, inode);
+		if (!err && IS_DIRSYNC(dir))
+			ext4_handle_sync(handle);
 	}
-	ext4_journal_stop(handle);
+	if (handle)
+		ext4_journal_stop(handle);
 	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
 		goto retry;
 	return err;
@@ -2291,32 +2289,30 @@ static int ext4_mknod(struct inode *dir, struct dentry *dentry,
 {
 	handle_t *handle;
 	struct inode *inode;
-	int err, retries = 0;
+	int err, credits, retries = 0;
 
 	if (!new_valid_dev(rdev))
 		return -EINVAL;
 
 	dquot_initialize(dir);
 
+	credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
+		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
+		   EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb));
 retry:
-	handle = ext4_journal_start(dir, EXT4_HT_DIR,
-		(EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
-		 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
-		 EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb)));
-	if (IS_ERR(handle))
-		return PTR_ERR(handle);
-
-	if (IS_DIRSYNC(dir))
-		ext4_handle_sync(handle);
-
-	inode = ext4_new_inode(handle, dir, mode, &dentry->d_name, 0, NULL);
+	inode = ext4_new_inode_start_handle(dir, mode, &dentry->d_name, 0,
+					    NULL, EXT4_HT_DIR, credits);
+	handle = ext4_journal_current_handle();
 	err = PTR_ERR(inode);
 	if (!IS_ERR(inode)) {
 		init_special_inode(inode, inode->i_mode, rdev);
 		inode->i_op = &ext4_special_inode_operations;
 		err = ext4_add_nondir(handle, dentry, inode);
+		if (!err && IS_DIRSYNC(dir))
+			ext4_handle_sync(handle);
 	}
-	ext4_journal_stop(handle);
+	if (handle)
+		ext4_journal_stop(handle);
 	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
 		goto retry;
 	return err;
@@ -2408,26 +2404,21 @@ static int ext4_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 {
 	handle_t *handle;
 	struct inode *inode;
-	int err, retries = 0;
+	int err, credits, retries = 0;
 
 	if (EXT4_DIR_LINK_MAX(dir))
 		return -EMLINK;
 
 	dquot_initialize(dir);
 
+	credits = (EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
+		   EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
+		   EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb));
 retry:
-	handle = ext4_journal_start(dir, EXT4_HT_DIR,
-		(EXT4_DATA_TRANS_BLOCKS(dir->i_sb) +
-		 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
-		 EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb)));
-	if (IS_ERR(handle))
-		return PTR_ERR(handle);
-
-	if (IS_DIRSYNC(dir))
-		ext4_handle_sync(handle);
-
-	inode = ext4_new_inode(handle, dir, S_IFDIR | mode,
-			       &dentry->d_name, 0, NULL);
+	inode = ext4_new_inode_start_handle(dir, S_IFDIR | mode,
+					    &dentry->d_name,
+					    0, NULL, EXT4_HT_DIR, credits);
+	handle = ext4_journal_current_handle();
 	err = PTR_ERR(inode);
 	if (IS_ERR(inode))
 		goto out_stop;
@@ -2455,8 +2446,12 @@ static int ext4_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
 		goto out_clear_inode;
 	unlock_new_inode(inode);
 	d_instantiate(dentry, inode);
+	if (IS_DIRSYNC(dir))
+		ext4_handle_sync(handle);
+
 out_stop:
-	ext4_journal_stop(handle);
+	if (handle)
+		ext4_journal_stop(handle);
 	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
 		goto retry;
 	return err;
@@ -2883,15 +2878,10 @@ static int ext4_symlink(struct inode *dir,
 			  EXT4_MAXQUOTAS_INIT_BLOCKS(dir->i_sb);
 	}
 retry:
-	handle = ext4_journal_start(dir, EXT4_HT_DIR, credits);
-	if (IS_ERR(handle))
-		return PTR_ERR(handle);
-
-	if (IS_DIRSYNC(dir))
-		ext4_handle_sync(handle);
-
-	inode = ext4_new_inode(handle, dir, S_IFLNK|S_IRWXUGO,
-			       &dentry->d_name, 0, NULL);
+	inode = ext4_new_inode_start_handle(dir, S_IFLNK|S_IRWXUGO,
+					    &dentry->d_name, 0, NULL,
+					    EXT4_HT_DIR, credits);
+	handle = ext4_journal_current_handle();
 	err = PTR_ERR(inode);
 	if (IS_ERR(inode))
 		goto out_stop;
@@ -2944,8 +2934,12 @@ static int ext4_symlink(struct inode *dir,
 	}
 	EXT4_I(inode)->i_disksize = inode->i_size;
 	err = ext4_add_nondir(handle, dentry, inode);
+	if (!err && IS_DIRSYNC(dir))
+		ext4_handle_sync(handle);
+
 out_stop:
-	ext4_journal_stop(handle);
+	if (handle)
+		ext4_journal_stop(handle);
 	if (err == -ENOSPC && ext4_should_retry_alloc(dir->i_sb, &retries))
 		goto retry;
 	return err;