Patch "NFS: nfs_set_pgio_error sometimes misses errors" has been added to the 4.1-stable tree

Patch "NFS: nfs_set_pgio_error sometimes misses errors" has been added to the 4.1-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    NFS: nfs_set_pgio_error sometimes misses errors

to the 4.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     nfs-nfs_set_pgio_error-sometimes-misses-errors.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From e9ae58aeee8842a50f7e199d602a5ccb2e41a95f Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust@primarydata.com>
Date: Mon, 17 Aug 2015 12:57:07 -0500
Subject: NFS: nfs_set_pgio_error sometimes misses errors

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

commit e9ae58aeee8842a50f7e199d602a5ccb2e41a95f upstream.

We should ensure that we always set the pgio_header's error field
if a READ or WRITE RPC call returns an error. The current code depends
on 'hdr->good_bytes' always being initialised to a large value, which
is not always done correctly by callers.
When this happens, applications may end up missing important errors.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/nfs/pagelist.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -77,8 +77,8 @@ EXPORT_SYMBOL_GPL(nfs_pgheader_init);
 void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos)
 {
 	spin_lock(&hdr->lock);
-	if (pos < hdr->io_start + hdr->good_bytes) {
-		set_bit(NFS_IOHDR_ERROR, &hdr->flags);
+	if (!test_and_set_bit(NFS_IOHDR_ERROR, &hdr->flags)
+	    || pos < hdr->io_start + hdr->good_bytes) {
 		clear_bit(NFS_IOHDR_EOF, &hdr->flags);
 		hdr->good_bytes = pos - hdr->io_start;
 		hdr->error = error;


Patches currently in stable-queue which might be from trond.myklebust@primarydata.com are

queue-4.1/nfs41-flexfiles-zero-out-ds-write-wcc.patch
queue-4.1/nfs-nfs_set_pgio_error-sometimes-misses-errors.patch
queue-4.1/nfs-fix-a-null-pointer-dereference-of-migration-recovery-ops-for-v4.2-client.patch
queue-4.1/sunrpc-xs_reset_transport-must-mark-the-connection-as-disconnected.patch
queue-4.1/nfs-don-t-let-the-ctime-override-attribute-barriers.patch
queue-4.1/sunrpc-fix-a-thinko-in-xs_connect.patch
queue-4.1/nfsv4-don-t-set-setattr-for-o_rdonly-o_excl.patch
queue-4.1/nfs41-flexfiles-update-inode-after-write-finishes.patch
queue-4.1/nfsv4.1-pnfs-fix-borken-function-_same_data_server_addrs_locked.patch
queue-4.1/nfsv4-force-a-post-op-attribute-update-when-holding-a-delegation.patch
queue-4.1/nfsv4-pnfs-ensure-we-don-t-miss-a-file-extension.patch
queue-4.1/nfsv4.1-flexfiles-fix-a-protocol-error-in-layoutreturn.patch
queue-4.1/revert-nfsv4-remove-incorrect-check-in-can_open_delegated.patch
queue-4.1/nfsv4.1-fix-a-protocol-issue-with-close-stateids.patch