filemap: update ki_pos in generic_perform_write

All callers of generic_perform_write need to updated ki_pos, move it into
common code.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Xiubo Li <[email protected]>
Reviewed-by: Damien Le Moal <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Acked-by: Theodore Ts'o <[email protected]>
Acked-by: Darrick J. Wong <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Andreas Gruenbacher <[email protected]>
Cc: Anna Schumaker <[email protected]>
Cc: Chao Yu <[email protected]>
Cc: Christian Brauner <[email protected]>
Cc: Ilya Dryomov <[email protected]>
Cc: Jaegeuk Kim <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Johannes Thumshirn <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Miklos Szeredi <[email protected]>
Cc: Miklos Szeredi <[email protected]>
Cc: Trond Myklebust <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

fs/ceph/file.c

@@ -1891,8 +1891,6 @@ retry_snap:
 		 * can not run at the same time
 		 */
 		written = generic_perform_write(iocb, from);
-		if (likely(written >= 0))
-			iocb->ki_pos = pos + written;
 		ceph_end_io_write(inode);
 	}
 

fs/ext4/file.c

@@ -289,12 +289,9 @@ static ssize_t ext4_buffered_write_iter(struct kiocb *iocb,
 
 out:
 	inode_unlock(inode);
-	if (likely(ret > 0)) {
-		iocb->ki_pos += ret;
-		ret = generic_write_sync(iocb, ret);
-	}
-
-	return ret;
+	if (unlikely(ret <= 0))
+		return ret;
+	return generic_write_sync(iocb, ret);
 }
 
 static ssize_t ext4_handle_inode_extension(struct inode *inode, loff_t offset,

fs/f2fs/file.c

@@ -4520,7 +4520,6 @@ static ssize_t f2fs_buffered_write_iter(struct kiocb *iocb,
 	ret = generic_perform_write(iocb, from);
 
 	if (ret > 0) {
-		iocb->ki_pos += ret;
 		f2fs_update_iostat(F2FS_I_SB(inode), inode,
 						APP_BUFFERED_IO, ret);
 	}

fs/nfs/file.c

@@ -655,7 +655,6 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
 		goto out;
 
 	written = result;
-	iocb->ki_pos += written;
 	nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
 
 	if (mntflags & NFS_MOUNT_WRITE_EAGER) {

mm/filemap.c

@@ -3930,7 +3930,10 @@ again:
 		balance_dirty_pages_ratelimited(mapping);
 	} while (iov_iter_count(i));
 
-	return written ? written : status;
+	if (!written)
+		return status;
+	iocb->ki_pos += written;
+	return written;
 }
 EXPORT_SYMBOL(generic_perform_write);
 
@@ -4007,7 +4010,6 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		endbyte = pos + status - 1;
 		err = filemap_write_and_wait_range(mapping, pos, endbyte);
 		if (err == 0) {
-			iocb->ki_pos = endbyte + 1;
 			written += status;
 			invalidate_mapping_pages(mapping,
 						 pos >> PAGE_SHIFT,
@@ -4020,8 +4022,6 @@ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 		}
 	} else {
 		written = generic_perform_write(iocb, from);
-		if (likely(written > 0))
-			iocb->ki_pos += written;
 	}
 out:
 	return written ? written : err;