Revert "nfs: ensure correct writeback errors are returned on close()"

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4T2WV
CVE: NA

--------------------------------

This reverts commit 67dd23f9.

filemap_sample_wb_err() will return 0 if nobody has seen the error yet,
then filemap_check_wb_err() will return the unchanged writeback error.

Reproducer:
        nfs server               |       nfs client
 --------------------------------|----------------------------------------------
 # No space left on server       |
 fallocate -l 100G /server/nospc |
                                 |
                                 | mount -t nfs $nfs_server_ip:/ /mnt
                                 |
                                 | # Expected error: No space left on device
                                 | dd if=/dev/zero of=/mnt/file count=1 ibs=1K
                                 |
                                 | # Release space on mountpoint
                                 | rm /mnt/nospc
                                 |
                                 | # Unexpected error: No space left on device
                                 | dd if=/dev/zero of=/mnt/file count=1 ibs=1K
Signed-off-by: NChenXiaoSong <chenxiaosong2@huawei.com>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

fs/nfs/file.c

@@ -140,7 +140,6 @@ static int
 nfs_file_flush(struct file *file, fl_owner_t id)
 {
 	struct inode	*inode = file_inode(file);
-	errseq_t since;
 
 	dprintk("NFS: flush(%pD2)\n", file);
 
@@ -149,9 +148,7 @@ nfs_file_flush(struct file *file, fl_owner_t id)
 		return 0;
 
 	/* Flush writes to the server and return any errors */
-	since = filemap_sample_wb_err(file->f_mapping);
-	nfs_wb_all(inode);
-	return filemap_check_wb_err(file->f_mapping, since);
+	return nfs_wb_all(inode);
 }
 
 ssize_t

fs/nfs/nfs4file.c

@@ -111,7 +111,6 @@ static int
 nfs4_file_flush(struct file *file, fl_owner_t id)
 {
 	struct inode	*inode = file_inode(file);
-	errseq_t since;
 
 	dprintk("NFS: flush(%pD2)\n", file);
 
@@ -127,9 +126,7 @@ nfs4_file_flush(struct file *file, fl_owner_t id)
 		return filemap_fdatawrite(file->f_mapping);
 
 	/* Flush writes to the server and return any errors */
-	since = filemap_sample_wb_err(file->f_mapping);
-	nfs_wb_all(inode);
-	return filemap_check_wb_err(file->f_mapping, since);
+	return nfs_wb_all(inode);
 }
 
 #ifdef CONFIG_NFS_V4_2