[PATCH 5.7 157/204] nfs: nfs_file_write() should check for writeback errors

[Greg Kroah-Hartman]

From: Scott Mayhew <smay...@redhat.com>

[ Upstream commit ce368536dd614452407dc31e2449eb84681a06af ]

The NFS_CONTEXT_ERROR_WRITE flag (as well as the check of said flag) was
removed by commit 6fbda89b257f.  The absence of an error check allows
writes to be continually queued up for a server that may no longer be
able to handle them.  Fix it by adding an error check using the generic
error reporting functions.

Fixes: 6fbda89b257f ("NFS: Replace custom error reporting mechanism with 
generic one")
Signed-off-by: Scott Mayhew <smay...@redhat.com>
Signed-off-by: Trond Myklebust <trond.mykleb...@hammerspace.com>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 fs/nfs/file.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index d72496efa17b0..63940a7a70be1 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -590,12 +590,14 @@ static const struct vm_operations_struct nfs_file_vm_ops 
= {
        .page_mkwrite = nfs_vm_page_mkwrite,
 };
 
-static int nfs_need_check_write(struct file *filp, struct inode *inode)
+static int nfs_need_check_write(struct file *filp, struct inode *inode,
+                               int error)
 {
        struct nfs_open_context *ctx;
 
        ctx = nfs_file_open_context(filp);
-       if (nfs_ctx_key_to_expire(ctx, inode))
+       if (nfs_error_is_fatal_on_server(error) ||
+           nfs_ctx_key_to_expire(ctx, inode))
                return 1;
        return 0;
 }
@@ -606,6 +608,8 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter 
*from)
        struct inode *inode = file_inode(file);
        unsigned long written = 0;
        ssize_t result;
+       errseq_t since;
+       int error;
 
        result = nfs_key_timeout_notify(file, inode);
        if (result)
@@ -630,6 +634,7 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter 
*from)
        if (iocb->ki_pos > i_size_read(inode))
                nfs_revalidate_mapping(inode, file->f_mapping);
 
+       since = filemap_sample_wb_err(file->f_mapping);
        nfs_start_io_write(inode);
        result = generic_write_checks(iocb, from);
        if (result > 0) {
@@ -648,7 +653,8 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter 
*from)
                goto out;
 
        /* Return error values */
-       if (nfs_need_check_write(file, inode)) {
+       error = filemap_check_wb_err(file->f_mapping, since);
+       if (nfs_need_check_write(file, inode, error)) {
                int err = nfs_wb_all(inode);
                if (err < 0)
                        result = err;
-- 
2.25.1