ext4: factor out ext4_do_fallocate()

[ Upstream commit fd2f764826df5489b849a8937b5a093aae5b1816 ]

Now the real job of normal fallocate are open coded in ext4_fallocate(),
factor out a new helper ext4_do_fallocate() to do the real job, like
others functions (e.g. ext4_zero_range()) in ext4_fallocate() do, this
can make the code more clear, no functional changes.

Signed-off-by: Zhang Yi <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Reviewed-by: Ojaswin Mujoo <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Theodore Ts'o <[email protected]>
Stable-dep-of: 29ec9bed2395 ("ext4: fix incorrect punch max_end")
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: zhangyi089

fs/ext4/extents.c

@@ -4690,6 +4690,58 @@ static long ext4_zero_range(struct file *file, loff_t offset,
 	return ret;
 }
 
+static long ext4_do_fallocate(struct file *file, loff_t offset,
+			      loff_t len, int mode)
+{
+	struct inode *inode = file_inode(file);
+	loff_t end = offset + len;
+	loff_t new_size = 0;
+	ext4_lblk_t start_lblk, len_lblk;
+	int ret;
+
+	trace_ext4_fallocate_enter(inode, offset, len, mode);
+
+	start_lblk = offset >> inode->i_blkbits;
+	len_lblk = EXT4_MAX_BLOCKS(len, offset, inode->i_blkbits);
+
+	inode_lock(inode);
+
+	/* We only support preallocation for extent-based files only. */
+	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
+
+	if (!(mode & FALLOC_FL_KEEP_SIZE) &&
+	    (end > inode->i_size || end > EXT4_I(inode)->i_disksize)) {
+		new_size = end;
+		ret = inode_newsize_ok(inode, new_size);
+		if (ret)
+			goto out;
+	}
+
+	/* Wait all existing dio workers, newcomers will block on i_rwsem */
+	inode_dio_wait(inode);
+
+	ret = file_modified(file);
+	if (ret)
+		goto out;
+
+	ret = ext4_alloc_file_blocks(file, start_lblk, len_lblk, new_size,
+				     EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT);
+	if (ret)
+		goto out;
+
+	if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
+		ret = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
+					EXT4_I(inode)->i_sync_tid);
+	}
+out:
+	inode_unlock(inode);
+	trace_ext4_fallocate_exit(inode, offset, len_lblk, ret);
+	return ret;
+}
+
 /*
  * preallocate space for a file. This implements ext4's fallocate file
  * operation, which gets called from sys_fallocate system call.
@@ -4700,12 +4752,7 @@ static long ext4_zero_range(struct file *file, loff_t offset,
 long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 {
 	struct inode *inode = file_inode(file);
-	loff_t new_size = 0;
-	unsigned int max_blocks;
-	int ret = 0;
-	int flags;
-	ext4_lblk_t lblk;
-	unsigned int blkbits = inode->i_blkbits;
+	int ret;
 
 	/*
 	 * Encrypted inodes can't handle collapse range or insert
@@ -4727,71 +4774,19 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 	ret = ext4_convert_inline_data(inode);
 	inode_unlock(inode);
 	if (ret)
-		goto exit;
+		return ret;
 
-	if (mode & FALLOC_FL_PUNCH_HOLE) {
+	if (mode & FALLOC_FL_PUNCH_HOLE)
 		ret = ext4_punch_hole(file, offset, len);
-		goto exit;
-	}
-
-	if (mode & FALLOC_FL_COLLAPSE_RANGE) {
+	else if (mode & FALLOC_FL_COLLAPSE_RANGE)
 		ret = ext4_collapse_range(file, offset, len);
-		goto exit;
-	}
-
-	if (mode & FALLOC_FL_INSERT_RANGE) {
+	else if (mode & FALLOC_FL_INSERT_RANGE)
 		ret = ext4_insert_range(file, offset, len);
-		goto exit;
-	}
-
-	if (mode & FALLOC_FL_ZERO_RANGE) {
+	else if (mode & FALLOC_FL_ZERO_RANGE)
 		ret = ext4_zero_range(file, offset, len, mode);
-		goto exit;
-	}
-	trace_ext4_fallocate_enter(inode, offset, len, mode);
-	lblk = offset >> blkbits;
-
-	max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
-	flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
-
-	inode_lock(inode);
-
-	/*
-	 * We only support preallocation for extent-based files only
-	 */
-	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
-		ret = -EOPNOTSUPP;
-		goto out;
-	}
-
-	if (!(mode & FALLOC_FL_KEEP_SIZE) &&
-	    (offset + len > inode->i_size ||
-	     offset + len > EXT4_I(inode)->i_disksize)) {
-		new_size = offset + len;
-		ret = inode_newsize_ok(inode, new_size);
-		if (ret)
-			goto out;
-	}
-
-	/* Wait all existing dio workers, newcomers will block on i_rwsem */
-	inode_dio_wait(inode);
-
-	ret = file_modified(file);
-	if (ret)
-		goto out;
-
-	ret = ext4_alloc_file_blocks(file, lblk, max_blocks, new_size, flags);
-	if (ret)
-		goto out;
+	else
+		ret = ext4_do_fallocate(file, offset, len, mode);
 
-	if (file->f_flags & O_SYNC && EXT4_SB(inode->i_sb)->s_journal) {
-		ret = ext4_fc_commit(EXT4_SB(inode->i_sb)->s_journal,
-					EXT4_I(inode)->i_sync_tid);
-	}
-out:
-	inode_unlock(inode);
-	trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
-exit:
 	return ret;
 }