cifs: define superblock-level cache index objects and register them

Define superblock-level cache index objects (managed by cifsTconInfo structs).
Each superblock object is created in a server-level index object and in itself
an index into which inode-level objects are inserted.

The superblock object is keyed by sharename. The UniqueId/IndexNumber is used to
validate that the exported share is the same since we accessed it last time.

Signed-off-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>

diff --git a/fs/cifs/cache.c b/fs/cifs/cache.c
index f46468fb6a90aee7e3783aff5109c4e5f36c1dc8..15532abdac14ffcbef46dc51ac4d238827c91b24 100644 (file)
--- a/fs/cifs/cache.c
+++ b/fs/cifs/cache.c
@@ -106,3 +106,112 @@ const struct fscache_cookie_def cifs_fscache_server_index_def = {
        .type = FSCACHE_COOKIE_TYPE_INDEX,
        .get_key = cifs_server_get_key,
 };
+
+/*
+ * Auxiliary data attached to CIFS superblock within the cache
+ */
+struct cifs_fscache_super_auxdata {
+       u64     resource_id;            /* unique server resource id */
+};
+
+static char *extract_sharename(const char *treename)
+{
+       const char *src;
+       char *delim, *dst;
+       int len;
+
+       /* skip double chars at the beginning */
+       src = treename + 2;
+
+       /* share name is always preceded by '\\' now */
+       delim = strchr(src, '\\');
+       if (!delim)
+               return ERR_PTR(-EINVAL);
+       delim++;
+       len = strlen(delim);
+
+       /* caller has to free the memory */
+       dst = kstrndup(delim, len, GFP_KERNEL);
+       if (!dst)
+               return ERR_PTR(-ENOMEM);
+
+       return dst;
+}
+
+/*
+ * Superblock object currently keyed by share name
+ */
+static uint16_t cifs_super_get_key(const void *cookie_netfs_data, void *buffer,
+                                  uint16_t maxbuf)
+{
+       const struct cifsTconInfo *tcon = cookie_netfs_data;
+       char *sharename;
+       uint16_t len;
+
+       sharename = extract_sharename(tcon->treeName);
+       if (IS_ERR(sharename)) {
+               cFYI(1, "CIFS: couldn't extract sharename\n");
+               sharename = NULL;
+               return 0;
+       }
+
+       len = strlen(sharename);
+       if (len > maxbuf)
+               return 0;
+
+       memcpy(buffer, sharename, len);
+
+       kfree(sharename);
+
+       return len;
+}
+
+static uint16_t
+cifs_fscache_super_get_aux(const void *cookie_netfs_data, void *buffer,
+                          uint16_t maxbuf)
+{
+       struct cifs_fscache_super_auxdata auxdata;
+       const struct cifsTconInfo *tcon = cookie_netfs_data;
+
+       memset(&auxdata, 0, sizeof(auxdata));
+       auxdata.resource_id = tcon->resource_id;
+
+       if (maxbuf > sizeof(auxdata))
+               maxbuf = sizeof(auxdata);
+
+       memcpy(buffer, &auxdata, maxbuf);
+
+       return maxbuf;
+}
+
+static enum
+fscache_checkaux cifs_fscache_super_check_aux(void *cookie_netfs_data,
+                                             const void *data,
+                                             uint16_t datalen)
+{
+       struct cifs_fscache_super_auxdata auxdata;
+       const struct cifsTconInfo *tcon = cookie_netfs_data;
+
+       if (datalen != sizeof(auxdata))
+               return FSCACHE_CHECKAUX_OBSOLETE;
+
+       memset(&auxdata, 0, sizeof(auxdata));
+       auxdata.resource_id = tcon->resource_id;
+
+       if (memcmp(data, &auxdata, datalen) != 0)
+               return FSCACHE_CHECKAUX_OBSOLETE;
+
+       return FSCACHE_CHECKAUX_OKAY;
+}
+
+/*
+ * Superblock object for FS-Cache
+ */
+const struct fscache_cookie_def cifs_fscache_super_index_def = {
+       .name = "CIFS.super",
+       .type = FSCACHE_COOKIE_TYPE_INDEX,
+       .get_key = cifs_super_get_key,
+       .get_aux = cifs_fscache_super_get_aux,
+       .check_aux = cifs_fscache_super_check_aux,
+};
+

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 793c8e3a0e537c3acc9a13172d1f4b9a46aeba6f..a3e403e7e163444f9da7b7e3d78d2c5543a5212e 100644 (file)
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -299,6 +299,10 @@ struct cifsTconInfo {
        bool local_lease:1; /* check leases (only) on local system not remote */
        bool broken_posix_open; /* e.g. Samba server versions < 3.3.2, 3.2.9 */
        bool need_reconnect:1; /* connection reset, tid now invalid */
+#ifdef CONFIG_CIFS_FSCACHE
+       u64 resource_id;                /* server resource id */
+       struct fscache_cookie *fscache; /* cookie for share */
+#endif
        /* BB add field for back pointer to sb struct(s)? */
 };
 

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index b2063ce113ec9e14e973b4b4ea8d0ab863388bfe..6e1fe3a7f27d275799e9483faeee887c0e31dab6 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1837,6 +1837,7 @@ cifs_put_tcon(struct cifsTconInfo *tcon)
        _FreeXid(xid);
 
        tconInfoFree(tcon);
+       cifs_fscache_release_super_cookie(tcon);
        cifs_put_smb_ses(ses);
 }
 
@@ -1906,6 +1907,8 @@ cifs_get_tcon(struct cifsSesInfo *ses, struct smb_vol *volume_info)
        list_add(&tcon->tcon_list, &ses->tcon_list);
        write_unlock(&cifs_tcp_ses_lock);
 
+       cifs_fscache_get_super_cookie(tcon);
+
        return tcon;
 
 out_fail:

diff --git a/fs/cifs/fscache.c b/fs/cifs/fscache.c
index ea97b76f8aa6295613f2af71b171f272e8851c41..eba9beb94a4c1fba3c23af95f185ce02a22bfdfa 100644 (file)
--- a/fs/cifs/fscache.c
+++ b/fs/cifs/fscache.c
@@ -39,3 +39,20 @@ void cifs_fscache_release_client_cookie(struct TCP_Server_Info *server)
        server->fscache = NULL;
 }
 
+void cifs_fscache_get_super_cookie(struct cifsTconInfo *tcon)
+{
+       struct TCP_Server_Info *server = tcon->ses->server;
+
+       tcon->fscache =
+               fscache_acquire_cookie(server->fscache,
+                               &cifs_fscache_super_index_def, tcon);
+       cFYI(1, "CIFS: get superblock cookie (0x%p/0x%p)",
+                               server->fscache, tcon->fscache);
+}
+
+void cifs_fscache_release_super_cookie(struct cifsTconInfo *tcon)
+{
+       cFYI(1, "CIFS: releasing superblock cookie (0x%p)", tcon->fscache);
+       fscache_relinquish_cookie(tcon->fscache, 0);
+       tcon->fscache = NULL;
+}

diff --git a/fs/cifs/fscache.h b/fs/cifs/fscache.h
index 8972306c58a5f4e866e18f6d73bbd9396ec3cc40..d2ba628b72cd3df7f06e77d0bd417336f48c3643 100644 (file)
--- a/fs/cifs/fscache.h
+++ b/fs/cifs/fscache.h
@@ -29,6 +29,7 @@
 
 extern struct fscache_netfs cifs_fscache_netfs;
 extern const struct fscache_cookie_def cifs_fscache_server_index_def;
+extern const struct fscache_cookie_def cifs_fscache_super_index_def;
 
 extern int cifs_fscache_register(void);
 extern void cifs_fscache_unregister(void);
@@ -38,6 +39,8 @@ extern void cifs_fscache_unregister(void);
  */
 extern void cifs_fscache_get_client_cookie(struct TCP_Server_Info *);
 extern void cifs_fscache_release_client_cookie(struct TCP_Server_Info *);
+extern void cifs_fscache_get_super_cookie(struct cifsTconInfo *);
+extern void cifs_fscache_release_super_cookie(struct cifsTconInfo *);
 
 #else /* CONFIG_CIFS_FSCACHE */
 static inline int cifs_fscache_register(void) { return 0; }
@@ -47,6 +50,9 @@ static inline void
 cifs_fscache_get_client_cookie(struct TCP_Server_Info *server) {}
 static inline void
 cifs_fscache_get_client_cookie(struct TCP_Server_Info *server); {}
+static inline void cifs_fscache_get_super_cookie(struct cifsTconInfo *tcon) {}
+static inline void
+cifs_fscache_release_super_cookie(struct cifsTconInfo *tcon) {}
 
 #endif /* CONFIG_CIFS_FSCACHE */
 

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index fe9b2f5fb492ea0bf1e3421d075755798d099faf..f884cb51622ad76e0dbe8dc4e100116676545d05 100644 (file)
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -807,6 +807,9 @@ struct inode *cifs_root_iget(struct super_block *sb, unsigned long ino)
        if (!inode)
                return ERR_PTR(-ENOMEM);
 
+       /* populate tcon->resource_id */
+       cifs_sb->tcon->resource_id = CIFS_I(inode)->uniqueid;
+
        if (rc && cifs_sb->tcon->ipc) {
                cFYI(1, "ipc connection - fake read inode");
                inode->i_mode |= S_IFDIR;