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>

1 files changed, 14 insertions, 20 deletions

diff --git a/fs/udf/file.c b/fs/udf/file.c
index 6834509a7e5a..ccab8b78e363 100644
--- 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);