NFS: Fix regression whereby fscache errors are appearing on 'nofsc' mounts

People are reporing seeing fscache errors being reported concerning
duplicate cookies even in cases where they are not setting up fscache
at all. The rule needs to be that if fscache is not enabled, then it
should have no side effects at all.

To ensure this is the case, we disable fscache completely on all superblocks
for which the 'fsc' mount option was not set. In order to avoid issues
with '-oremount', we also disable the ability to turn fscache on via
remount.

Fixes: f1fe29b4a02d ("NFS: Use i_writecount to control whether...")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=200145
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Steve Dickson <steved@redhat.com>
Cc: David Howells <dhowells@redhat.com>

diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c
index 53507aa96b0b63df96dc504abd7dc952c50d00d8..3800ab6f08fa8f91465f6a881a89098cd413eafa 100644 (file)
--- a/fs/nfs/fscache.c
+++ b/fs/nfs/fscache.c
@@ -114,6 +114,10 @@ void nfs_fscache_get_super_cookie(struct super_block *sb, const char *uniq, int
        struct rb_node **p, *parent;
        int diff;
 
+       nfss->fscache_key = NULL;
+       nfss->fscache = NULL;
+       if (!(nfss->options & NFS_OPTION_FSCACHE))
+               return;
        if (!uniq) {
                uniq = "";
                ulen = 1;
@@ -226,10 +230,11 @@ void nfs_fscache_release_super_cookie(struct super_block *sb)
 void nfs_fscache_init_inode(struct inode *inode)
 {
        struct nfs_fscache_inode_auxdata auxdata;
+       struct nfs_server *nfss = NFS_SERVER(inode);
        struct nfs_inode *nfsi = NFS_I(inode);
 
        nfsi->fscache = NULL;
-       if (!S_ISREG(inode->i_mode))
+       if (!(nfss->fscache && S_ISREG(inode->i_mode)))
                return;
 
        memset(&auxdata, 0, sizeof(auxdata));

diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h
index 25a75e40d91d983f1ce7124ccef80d8ddff9050d..ad041cfbf9ec0fe616441dc653225c30f0983ca8 100644 (file)
--- a/fs/nfs/fscache.h
+++ b/fs/nfs/fscache.h
@@ -182,7 +182,7 @@ static inline void nfs_fscache_wait_on_invalidate(struct inode *inode)
  */
 static inline const char *nfs_server_fscache_state(struct nfs_server *server)
 {
-       if (server->fscache && (server->options & NFS_OPTION_FSCACHE))
+       if (server->fscache)
                return "yes";
        return "no ";
 }

diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 628631e2e34fe630f6e24a814f43551d93484135..703f595dce90c1bfb8dfad1ca589221cc7f6f0b5 100644 (file)
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -2260,6 +2260,7 @@ nfs_compare_remount_data(struct nfs_server *nfss,
            data->acdirmin != nfss->acdirmin / HZ ||
            data->acdirmax != nfss->acdirmax / HZ ||
            data->timeo != (10U * nfss->client->cl_timeout->to_initval / HZ) ||
+           (data->options & NFS_OPTION_FSCACHE) != (nfss->options & NFS_OPTION_FSCACHE) ||
            data->nfs_server.port != nfss->port ||
            data->nfs_server.addrlen != nfss->nfs_client->cl_addrlen ||
            !rpc_cmp_addr((struct sockaddr *)&data->nfs_server.address,