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 761841903160..3f0b9339d823 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;