[PATCH] nfs: Handle NFSERR_IO as symlink

The Linux kernel's NFSd changed [1] its response code on access of symbolic
links to be RFC 1094 compliant. When a symbolic link is encountered in NFSv2
mode it returns no longer NFSERR_INVAL (22) but NFSERR_IO (5).

This change from 7.0-rc1 got backported to different other versions like
6.12.75 and 6.18.14. Therefore, U-Boot needs to handle this new response
code.

[1] https://lore.kernel.org/all/[email protected]/

Signed-off-by: Jörg Sommer <[email protected]>
---

There's a discussion going how to hande this in the kernel:
https://lore.kernel.org/all/[email protected]/

 net/nfs-common.c | 3 ++-
 net/nfs-common.h | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/nfs-common.c b/net/nfs-common.c
index 637fcfd9bb8..ee24cd07196 100644
--- a/net/nfs-common.c
+++ b/net/nfs-common.c
@@ -855,7 +855,8 @@ void nfs_pkt_recv(uchar *pkt, unsigned int len)
 		if (rlen > 0) {
 			nfs_offset += rlen;
 			nfs_send();
-		} else if ((rlen == -NFSERR_ISDIR) || (rlen == -NFSERR_INVAL)) {
+		} else if ((rlen == -NFSERR_ISDIR) || (rlen == -NFSERR_INVAL) ||
+			   (rlen == -NFSERR_IO)) {
 			/* symbolic link */
 			nfs_state = STATE_READLINK_REQ;
 			nfs_send();
diff --git a/net/nfs-common.h b/net/nfs-common.h
index a19b98b7b1f..04671d3c87a 100644
--- a/net/nfs-common.h
+++ b/net/nfs-common.h
@@ -23,6 +23,7 @@
 
 #define NFSERR_PERM     1
 #define NFSERR_NOENT    2
+#define NFSERR_IO       5
 #define NFSERR_ACCES    13
 #define NFSERR_ISDIR    21
 #define NFSERR_INVAL    22
-- 
2.55.0