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 f46468f..15532ab 100644
--- a/fs/cifs/cache.c
+++ b/fs/cifs/cache.c
@@ -106,3 +106,112 @@
.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,
+};
+