6 files changed, 214 insertions, 2 deletions

diff --git a/fs/nfs/fscache-index.c b/fs/nfs/fscache-index.c
index ff14b032459b..a824050be807 100644
--- a/fs/nfs/fscache-index.c
+++ b/fs/nfs/fscache-index.c
@@ -112,3 +112,37 @@ const struct fscache_cookie_def nfs_fscache_server_index_def = {
         .type           = FSCACHE_COOKIE_TYPE_INDEX,
         .get_key        = nfs_server_get_key,
 };
+
+/*
+ * Generate a key to describe a superblock key in the main NFS index
+ */
+static uint16_t nfs_super_get_key(const void *cookie_netfs_data,
+                                  void *buffer, uint16_t bufmax)
+{
+        const struct nfs_fscache_key *key;
+        const struct nfs_server *nfss = cookie_netfs_data;
+        uint16_t len;
+
+        key = nfss->fscache_key;
+        len = sizeof(key->key) + key->key.uniq_len;
+        if (len > bufmax) {
+                len = 0;
+        } else {
+                memcpy(buffer, &key->key, sizeof(key->key));
+                memcpy(buffer + sizeof(key->key),
+                       key->key.uniquifier, key->key.uniq_len);
+        }
+
+        return len;
+}
+
+/*
+ * Define the superblock object for FS-Cache.  This is used to describe a
+ * superblock object to fscache_acquire_cookie().  It is keyed by all the NFS
+ * parameters that might cause a separate superblock.
+ */
+const struct fscache_cookie_def nfs_fscache_super_index_def = {
+        .name           = "NFS.super",
+        .type           = FSCACHE_COOKIE_TYPE_INDEX,
+        .get_key        = nfs_super_get_key,
+};
diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c
index c3f056f89477..ab2de2c92b21 100644
--- a/fs/nfs/fscache.c
+++ b/fs/nfs/fscache.c
@@ -23,6 +23,9 @@
 
 #define NFSDBG_FACILITY         NFSDBG_FSCACHE
 
+static struct rb_root nfs_fscache_keys = RB_ROOT;
+static DEFINE_SPINLOCK(nfs_fscache_keys_lock);
+
 /*
  * Get the per-client index cookie for an NFS client if the appropriate mount
  * flag was set
@@ -50,3 +53,116 @@ void nfs_fscache_release_client_cookie(struct nfs_client *clp)
         fscache_relinquish_cookie(clp->fscache, 0);
         clp->fscache = NULL;
 }
+
+/*
+ * Get the cache cookie for an NFS superblock.  We have to handle
+ * uniquification here because the cache doesn't do it for us.
+ */
+void nfs_fscache_get_super_cookie(struct super_block *sb,
+                                  struct nfs_parsed_mount_data *data)
+{
+        struct nfs_fscache_key *key, *xkey;
+        struct nfs_server *nfss = NFS_SB(sb);
+        struct rb_node **p, *parent;
+        const char *uniq = data->fscache_uniq ?: "";
+        int diff, ulen;
+
+        ulen = strlen(uniq);
+        key = kzalloc(sizeof(*key) + ulen, GFP_KERNEL);
+        if (!key)
+                return;
+
+        key->nfs_client = nfss->nfs_client;
+        key->key.super.s_flags = sb->s_flags & NFS_MS_MASK;
+        key->key.nfs_server.flags = nfss->flags;
+        key->key.nfs_server.rsize = nfss->rsize;
+        key->key.nfs_server.wsize = nfss->wsize;
+        key->key.nfs_server.acregmin = nfss->acregmin;
+        key->key.nfs_server.acregmax = nfss->acregmax;
+        key->key.nfs_server.acdirmin = nfss->acdirmin;
+        key->key.nfs_server.acdirmax = nfss->acdirmax;
+        key->key.nfs_server.fsid = nfss->fsid;
+        key->key.rpc_auth.au_flavor = nfss->client->cl_auth->au_flavor;
+
+        key->key.uniq_len = ulen;
+        memcpy(key->key.uniquifier, uniq, ulen);
+
+        spin_lock(&nfs_fscache_keys_lock);
+        p = &nfs_fscache_keys.rb_node;
+        parent = NULL;
+        while (*p) {
+                parent = *p;
+                xkey = rb_entry(parent, struct nfs_fscache_key, node);
+
+                if (key->nfs_client < xkey->nfs_client)
+                        goto go_left;
+                if (key->nfs_client > xkey->nfs_client)
+                        goto go_right;
+
+                diff = memcmp(&key->key, &xkey->key, sizeof(key->key));
+                if (diff < 0)
+                        goto go_left;
+                if (diff > 0)
+                        goto go_right;
+
+                if (key->key.uniq_len == 0)
+                        goto non_unique;
+                diff = memcmp(key->key.uniquifier,
+                              xkey->key.uniquifier,
+                              key->key.uniq_len);
+                if (diff < 0)
+                        goto go_left;
+                if (diff > 0)
+                        goto go_right;
+                goto non_unique;
+
+        go_left:
+                p = &(*p)->rb_left;
+                continue;
+        go_right:
+                p = &(*p)->rb_right;
+        }
+
+        rb_link_node(&key->node, parent, p);
+        rb_insert_color(&key->node, &nfs_fscache_keys);
+        spin_unlock(&nfs_fscache_keys_lock);
+        nfss->fscache_key = key;
+
+        /* create a cache index for looking up filehandles */
+        nfss->fscache = fscache_acquire_cookie(nfss->nfs_client->fscache,
+                                               &nfs_fscache_super_index_def,
+                                               nfss);
+        dfprintk(FSCACHE, "NFS: get superblock cookie (0x%p/0x%p)\n",
+                 nfss, nfss->fscache);
+        return;
+
+non_unique:
+        spin_unlock(&nfs_fscache_keys_lock);
+        kfree(key);
+        nfss->fscache_key = NULL;
+        nfss->fscache = NULL;
+        printk(KERN_WARNING "NFS:"
+               " Cache request denied due to non-unique superblock keys\n");
+}
+
+/*
+ * release a per-superblock cookie
+ */
+void nfs_fscache_release_super_cookie(struct super_block *sb)
+{
+        struct nfs_server *nfss = NFS_SB(sb);
+
+        dfprintk(FSCACHE, "NFS: releasing superblock cookie (0x%p/0x%p)\n",
+                 nfss, nfss->fscache);
+
+        fscache_relinquish_cookie(nfss->fscache, 0);
+        nfss->fscache = NULL;
+
+        if (nfss->fscache_key) {
+                spin_lock(&nfs_fscache_keys_lock);
+                rb_erase(&nfss->fscache_key->node, &nfs_fscache_keys);
+                spin_unlock(&nfs_fscache_keys_lock);
+                kfree(nfss->fscache_key);
+                nfss->fscache_key = NULL;
+        }
+}
diff --git a/fs/nfs/fscache.h b/fs/nfs/fscache.h
index 1d864bedf154..22b971e8b380 100644
--- a/fs/nfs/fscache.h
+++ b/fs/nfs/fscache.h
@@ -20,10 +20,48 @@
 #ifdef CONFIG_NFS_FSCACHE
 
 /*
+ * set of NFS FS-Cache objects that form a superblock key
+ */
+struct nfs_fscache_key {
+        struct rb_node          node;
+        struct nfs_client       *nfs_client;    /* the server */
+
+        /* the elements of the unique key - as used by nfs_compare_super() and
+         * nfs_compare_mount_options() to distinguish superblocks */
+        struct {
+                struct {
+                        unsigned long   s_flags;        /* various flags
+                                                         * (& NFS_MS_MASK) */
+                } super;
+
+                struct {
+                        struct nfs_fsid fsid;
+                        int             flags;
+                        unsigned int    rsize;          /* read size */
+                        unsigned int    wsize;          /* write size */
+                        unsigned int    acregmin;       /* attr cache timeouts */
+                        unsigned int    acregmax;
+                        unsigned int    acdirmin;
+                        unsigned int    acdirmax;
+                } nfs_server;
+
+                struct {
+                        rpc_authflavor_t au_flavor;
+                } rpc_auth;
+
+                /* uniquifier - can be used if nfs_server.flags includes
+                 * NFS_MOUNT_UNSHARED  */
+                u8 uniq_len;
+                char uniquifier[0];
+        } key;
+};
+
+/*
  * fscache-index.c
  */
 extern struct fscache_netfs nfs_fscache_netfs;
 extern const struct fscache_cookie_def nfs_fscache_server_index_def;
+extern const struct fscache_cookie_def nfs_fscache_super_index_def;
 
 extern int nfs_fscache_register(void);
 extern void nfs_fscache_unregister(void);
@@ -34,6 +72,10 @@ extern void nfs_fscache_unregister(void);
 extern void nfs_fscache_get_client_cookie(struct nfs_client *);
 extern void nfs_fscache_release_client_cookie(struct nfs_client *);
 
+extern void nfs_fscache_get_super_cookie(struct super_block *,
+                                         struct nfs_parsed_mount_data *);
+extern void nfs_fscache_release_super_cookie(struct super_block *);
+
 #else /* CONFIG_NFS_FSCACHE */
 static inline int nfs_fscache_register(void) { return 0; }
 static inline void nfs_fscache_unregister(void) {}
@@ -41,5 +83,12 @@ static inline void nfs_fscache_unregister(void) {}
 static inline void nfs_fscache_get_client_cookie(struct nfs_client *clp) {}
 static inline void nfs_fscache_release_client_cookie(struct nfs_client *clp) {}
 
+static inline void nfs_fscache_get_super_cookie(
+        struct super_block *sb,
+        struct nfs_parsed_mount_data *data)
+{
+}
+static inline void nfs_fscache_release_super_cookie(struct super_block *sb) {}
+
 #endif /* CONFIG_NFS_FSCACHE */
 #endif /* _NFS_FSCACHE_H */
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 2041f68ff1cc..013070000c38 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -5,6 +5,8 @@
 #include <linux/mount.h>
 #include <linux/security.h>
 
+#define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS)
+
 struct nfs_string;
 
 /* Maximum number of readahead requests
@@ -41,6 +43,7 @@ struct nfs_parsed_mount_data {
         unsigned int            auth_flavor_len;
         rpc_authflavor_t        auth_flavors[1];
         char                    *client_address;
+        char                    *fscache_uniq;
 
         struct {
                 struct sockaddr_storage address;
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index 0942fcbbad3c..87f65ae07f32 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -60,6 +60,7 @@
 #include "delegation.h"
 #include "iostat.h"
 #include "internal.h"
+#include "fscache.h"
 
 #define NFSDBG_FACILITY         NFSDBG_VFS
 
@@ -1870,8 +1871,6 @@ static void nfs_clone_super(struct super_block *sb,
         nfs_initialise_sb(sb);
 }
 
-#define NFS_MS_MASK (MS_RDONLY|MS_NOSUID|MS_NODEV|MS_NOEXEC|MS_SYNCHRONOUS)
-
 static int nfs_compare_mount_options(const struct super_block *s, const struct nfs_server *b, int flags)
 {
         const struct nfs_server *a = s->s_fs_info;
@@ -2036,6 +2035,7 @@ static int nfs_get_sb(struct file_system_type *fs_type,
         if (!s->s_root) {
                 /* initial superblock/root creation */
                 nfs_fill_super(s, data);
+                nfs_fscache_get_super_cookie(s, data);
         }
 
         mntroot = nfs_get_root(s, mntfh);
@@ -2056,6 +2056,7 @@ static int nfs_get_sb(struct file_system_type *fs_type,
 out:
         kfree(data->nfs_server.hostname);
         kfree(data->mount_server.hostname);
+        kfree(data->fscache_uniq);
         security_free_mnt_opts(&data->lsm_opts);
 out_free_fh:
         kfree(mntfh);
@@ -2083,6 +2084,7 @@ static void nfs_kill_super(struct super_block *s)
 
         bdi_unregister(&server->backing_dev_info);
         kill_anon_super(s);
+        nfs_fscache_release_super_cookie(s);
         nfs_free_server(server);
 }
 
@@ -2390,6 +2392,7 @@ static int nfs4_get_sb(struct file_system_type *fs_type,
         if (!s->s_root) {
                 /* initial superblock/root creation */
                 nfs4_fill_super(s);
+                nfs_fscache_get_super_cookie(s, data);
         }
 
         mntroot = nfs4_get_root(s, mntfh);
@@ -2411,6 +2414,7 @@ out:
         kfree(data->client_address);
         kfree(data->nfs_server.export_path);
         kfree(data->nfs_server.hostname);
+        kfree(data->fscache_uniq);
         security_free_mnt_opts(&data->lsm_opts);
 out_free_fh:
         kfree(mntfh);
@@ -2437,6 +2441,7 @@ static void nfs4_kill_super(struct super_block *sb)
         kill_anon_super(sb);
 
         nfs4_renewd_prepare_shutdown(server);
+        nfs_fscache_release_super_cookie(sb);
         nfs_free_server(server);
 }
 
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index 0a374b9c5093..6ad75948cbf7 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -108,6 +108,11 @@ struct nfs_server {
         unsigned long           mount_time;     /* when this fs was mounted */
         dev_t                   s_dev;          /* superblock dev numbers */
 
+#ifdef CONFIG_NFS_FSCACHE
+        struct nfs_fscache_key  *fscache_key;   /* unique key for superblock */
+        struct fscache_cookie   *fscache;       /* superblock cookie */
+#endif
+
 #ifdef CONFIG_NFS_V4
         u32                     attr_bitmask[2];/* V4 bitmask representing the set
                                                    of attributes supported on this