switch generic_write_checks() to iocb and iter

... returning -E... upon error and amount of data left in iter after
(possible) truncation upon success.  Note, that normal case gives
a non-zero (positive) return value, so any tests for != 0 _must_ be
updated.

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

Conflicts:
	fs/ext4/file.c

1 files changed, 10 insertions, 9 deletions

diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index fc53ff065364..b93919f50f0f 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -2250,9 +2250,10 @@ out:
 static ssize_t ocfs2_file_write_iter(struct kiocb *iocb,
                                     struct iov_iter *from)
 {
-        int ret, direct_io, appending, rw_level, have_alloc_sem  = 0;
+        int direct_io, appending, rw_level, have_alloc_sem  = 0;
         int can_do_direct, has_refcount = 0;
         ssize_t written = 0;
+        ssize_t ret;
         size_t count = iov_iter_count(from), orig_count;
         loff_t old_size;
         u32 old_clusters;
@@ -2319,13 +2320,14 @@ relock:
                 ocfs2_inode_unlock(inode, 1);
         }
 
-        orig_count = count;
-        ret = generic_write_checks(file, &iocb->ki_pos, &count);
-        if (ret < 0) {
-                mlog_errno(ret);
+        orig_count = iov_iter_count(from);
+        ret = generic_write_checks(iocb, from);
+        if (ret <= 0) {
+                if (ret)
+                        mlog_errno(ret);
                 goto out;
         }
-        iov_iter_truncate(from, count);
+        count = ret;
 
         can_do_direct = direct_io;
         ret = ocfs2_prepare_inode_for_write(file, iocb->ki_pos, count, appending,
@@ -2349,7 +2351,7 @@ relock:
                 rw_level = -1;
 
                 direct_io = 0;
-                iov_iter_reexpand(from, count = orig_count);
+                iov_iter_reexpand(from, orig_count);
                 goto relock;
         }
 
@@ -2377,7 +2379,7 @@ relock:
                 loff_t endbyte;
                 ssize_t written_buffered;
                 written = generic_file_direct_write(iocb, from, iocb->ki_pos);
-                if (written < 0 || written == count) {
+                if (written < 0 || !iov_iter_count(from)) {
                         ret = written;
                         goto out_dio;
                 }
@@ -2385,7 +2387,6 @@ relock:
                 /*
                  * for completing the rest of the request.
                  */
-                count -= written;
                 written_buffered = generic_perform_write(file, from, iocb->ki_pos);
                 /*
                  * If generic_file_buffered_write() returned a synchronous error