udf_file_write_iter: reorder and simplify

it's easier to do generic_write_checks() first

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/udf/file.c b/fs/udf/file.c
index 6834509a7e5a7e782b0f58abc74fcb2eff44dda8..ccab8b78e3633ea9167afed946a124adc3a106ee 100644 (file)
--- a/fs/udf/file.c
+++ b/fs/udf/file.c
@@ -120,21 +120,27 @@ static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
        ssize_t retval;
        struct file *file = iocb->ki_filp;
        struct inode *inode = file_inode(file);
-       int err, pos;
        size_t count = iov_iter_count(from);
        struct udf_inode_info *iinfo = UDF_I(inode);
+       int err;
 
        mutex_lock(&inode->i_mutex);
+
+       retval = generic_write_checks(file, &iocb->ki_pos, &count);
+       if (retval)
+               goto out;
+
+       if (count == 0)
+               goto out;
+
+       iov_iter_truncate(from, count);
+
        down_write(&iinfo->i_data_sem);
        if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
-               if (file->f_flags & O_APPEND)
-                       pos = inode->i_size;
-               else
-                       pos = iocb->ki_pos;
+               loff_t end = iocb->ki_pos + iov_iter_count(from);
 
                if (inode->i_sb->s_blocksize <
-                               (udf_file_entry_alloc_offset(inode) +
-                                               pos + count)) {
+                               (udf_file_entry_alloc_offset(inode) + end)) {
                        err = udf_expand_file_adinicb(inode);
                        if (err) {
                                mutex_unlock(&inode->i_mutex);
@@ -142,24 +148,12 @@ static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
                                return err;
                        }
                } else {
-                       if (pos + count > inode->i_size)
-                               iinfo->i_lenAlloc = pos + count;
-                       else
-                               iinfo->i_lenAlloc = inode->i_size;
+                       iinfo->i_lenAlloc = max(end, inode->i_size);
                        up_write(&iinfo->i_data_sem);
                }
        } else
                up_write(&iinfo->i_data_sem);
 
-       retval = generic_write_checks(file, &iocb->ki_pos, &count);
-       if (retval)
-               goto out;
-
-       if (count == 0)
-               goto out;
-
-       iov_iter_truncate(from, count);
-
        retval = __generic_file_write_iter(iocb, from);
 out:
        mutex_unlock(&inode->i_mutex);