[PATCH v3 3/5] NFS: Don't report ENOSPC write errors twice

[trondmy@kernel.org]

From: Trond Myklebust <trond.myklebust@hammerspace.com>

Any errors reported by the write() system call need to be cleared from
the file descriptor's error tracking. The current call to nfs_wb_all()
causes the error to be reported, but since it doesn't call
file_check_and_advance_wb_err(), we can end up reporting the same error
a second time when the application calls fsync().

Note that since Linux 4.13, the rule is that EIO may be reported for
write(), but it must be reported by a subsequent fsync(), so let's just
drop reporting it in write.

The check for nfs_ctx_key_to_expire() is just a duplicate to the one
already in nfs_write_end(), so let's drop that too.

Reported-by: ChenXiaoSong <chenxiaosong2@huawei.com>
Fixes: ce368536dd61 ("nfs: nfs_file_write() should check for writeback errors")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 fs/nfs/file.c | 34 ++++++++++++++--------------------
 1 file changed, 14 insertions(+), 20 deletions(-)

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 7c380e555224..87e4cd5e8fe2 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -598,18 +598,6 @@ 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,
-				int error)
-{
-	struct nfs_open_context *ctx;
-
-	ctx = nfs_file_open_context(filp);
-	if (nfs_error_is_fatal_on_server(error) ||
-	    nfs_ctx_key_to_expire(ctx, inode))
-		return 1;
-	return 0;
-}
-
 ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
 {
 	struct file *file = iocb->ki_filp;
@@ -637,7 +625,7 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
 	if (iocb->ki_flags & IOCB_APPEND || iocb->ki_pos > i_size_read(inode)) {
 		result = nfs_revalidate_file_size(inode, file);
 		if (result)
-			goto out;
+			return result;
 	}
 
 	nfs_clear_invalid_mapping(file->f_mapping);
@@ -656,6 +644,7 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
 
 	written = result;
 	iocb->ki_pos += written;
+	nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
 
 	if (mntflags & NFS_MOUNT_WRITE_EAGER) {
 		result = filemap_fdatawrite_range(file->f_mapping,
@@ -673,17 +662,22 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
 	}
 	result = generic_write_sync(iocb, written);
 	if (result < 0)
-		goto out;
+		return result;
 
+out:
 	/* Return error values */
 	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;
+	switch (error) {
+	default:
+		break;
+	case -EDQUOT:
+	case -EFBIG:
+	case -ENOSPC:
+		nfs_wb_all(inode);
+		error = file_check_and_advance_wb_err(file);
+		if (error < 0)
+			result = error;
 	}
-	nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
-out:
 	return result;
 
 out_swapfile:
-- 
2.36.1