From 98de9ce6f6660d02aa72d7b9b17696fa68a2ed9b Mon Sep 17 00:00:00 2001
From: Frank Sorenson <sorenson@redhat.com>
Date: Mon, 2 Apr 2018 16:12:45 -0500
Subject: [PATCH] NFS: advance nfs_entry cookie only after decoding completes
successfully
In nfs[34]_decode_dirent, the cookie is advanced as soon as it is
read, but decoding may still fail later in the function, returning
an error. Because the cookie has been advanced, the failing entry
is not re-requested from the server, resulting in a missing directory
entry.
In addition, nfs v3 and v4 read the cookie at different locations
in the xdr_stream, so the behavior of the two can be inconsistent.
Fix these by reading the cookie into a temporary variable, and
only advancing the cookie once the entire entry has been decoded
from the xdr_stream successfully.
Signed-off-by: Frank Sorenson <sorenson@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
---
fs/nfs/nfs3xdr.c | 7 +++++--
fs/nfs/nfs4xdr.c | 7 +++++--
2 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c
index 6cd33bd5da87c..09ee36dd84262 100644
--- a/fs/nfs/nfs3xdr.c
+++ b/fs/nfs/nfs3xdr.c
@@ -1997,6 +1997,7 @@ int nfs3_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry,
struct nfs_entry old = *entry;
__be32 *p;
int error;
+ u64 new_cookie;
p = xdr_inline_decode(xdr, 4);
if (unlikely(p == NULL))
@@ -2019,8 +2020,7 @@ int nfs3_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry,
if (unlikely(error))
return error;
- entry->prev_cookie = entry->cookie;
- error = decode_cookie3(xdr, &entry->cookie);
+ error = decode_cookie3(xdr, &new_cookie);
if (unlikely(error))
return error;
@@ -2054,6 +2054,9 @@ int nfs3_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry,
zero_nfs_fh3(entry->fh);
}
+ entry->prev_cookie = entry->cookie;
+ entry->cookie = new_cookie;
+
return 0;
out_overflow:
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 51264f5d9d2a0..aa550fb08d2af 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -7518,6 +7518,7 @@ int nfs4_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry,
unsigned int savep;
uint32_t bitmap[3] = {0};
uint32_t len;
+ uint64_t new_cookie;
__be32 *p = xdr_inline_decode(xdr, 4);
if (unlikely(!p))
goto out_overflow;
@@ -7534,8 +7535,7 @@ int nfs4_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry,
p = xdr_inline_decode(xdr, 12);
if (unlikely(!p))
goto out_overflow;
- entry->prev_cookie = entry->cookie;
- p = xdr_decode_hyper(p, &entry->cookie);
+ p = xdr_decode_hyper(p, &new_cookie);
entry->len = be32_to_cpup(p);
p = xdr_inline_decode(xdr, entry->len);
@@ -7569,6 +7569,9 @@ int nfs4_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry,
if (entry->fattr->valid & NFS_ATTR_FATTR_TYPE)
entry->d_type = nfs_umode_to_dtype(entry->fattr->mode);
+ entry->prev_cookie = entry->cookie;
+ entry->cookie = new_cookie;
+
return 0;
out_overflow:
--
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