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, 6 insertions, 8 deletions

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 7618419..3f0b933 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -941,9 +941,9 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct ceph_osd_client *osdc =
 		&ceph_sb_to_client(inode->i_sb)->client->osdc;
-	ssize_t count = iov_iter_count(from), written = 0;
+	ssize_t count, written = 0;
 	int err, want, got;
-	loff_t pos = iocb->ki_pos;
+	loff_t pos;
 
 	if (ceph_snap(inode) != CEPH_NOSNAP)
 		return -EROFS;
@@ -953,14 +953,12 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	/* We can write back this queue in page reclaim */
 	current->backing_dev_info = inode_to_bdi(inode);
 
-	err = generic_write_checks(file, &pos, &count);
-	if (err)
-		goto out;
-
-	if (count == 0)
+	err = generic_write_checks(iocb, from);
+	if (err <= 0)
 		goto out;
-	iov_iter_truncate(from, count);
 
+	pos = iocb->ki_pos;
+	count = iov_iter_count(from);
 	err = file_remove_suid(file);
 	if (err)
 		goto out;