[PATCH 17/27] afs: Implement client support for the YFSVL.GetCellName RPC op

From: David Howells
Date: Fri May 29 2020 - 18:02:25 EST

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Implement client support for the YFSVL.GetCellName RPC operation by which
YFS permits the canonical cell name to be queried from a VL server.

Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---

fs/afs/afs.h | 2 -
fs/afs/afs_vl.h | 1
fs/afs/internal.h | 2 +
fs/afs/protocol_yfs.h | 2 -
fs/afs/vlclient.c | 111 ++++++++++++++++++++++++++++++++++++++++++++
include/trace/events/afs.h | 4 ++
6 files changed, 120 insertions(+), 2 deletions(-)

diff --git a/fs/afs/afs.h b/fs/afs/afs.h
index f8e34406243e..432cb4b23961 100644
--- a/fs/afs/afs.h
+++ b/fs/afs/afs.h
@@ -10,7 +10,7 @@

#include <linux/in.h>

-#define AFS_MAXCELLNAME 64 /* Maximum length of a cell name */
+#define AFS_MAXCELLNAME 256 /* Maximum length of a cell name */
#define AFS_MAXVOLNAME 64 /* Maximum length of a volume name */
#define AFS_MAXNSERVERS 8 /* Maximum servers in a basic volume record */
#define AFS_NMAXNSERVERS 13 /* Maximum servers in a N/U-class volume record */
diff --git a/fs/afs/afs_vl.h b/fs/afs/afs_vl.h
index e9b8029920ec..9c65ffb8a523 100644
--- a/fs/afs/afs_vl.h
+++ b/fs/afs/afs_vl.h
@@ -22,6 +22,7 @@ enum AFSVL_Operations {
VLGETENTRYBYNAMEU = 527, /* AFS Get VLDB entry by name (UUID-variant) */
VLGETADDRSU = 533, /* AFS Get addrs for fileserver */
YVLGETENDPOINTS = 64002, /* YFS Get endpoints for file/volume server */
+ YVLGETCELLNAME = 64014, /* YFS Get actual cell name */
VLGETCAPABILITIES = 65537, /* AFS Get server capabilities */
};

diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index dce03e068cab..3606cfa50832 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -116,6 +116,7 @@ struct afs_call {
long ret0; /* Value to reply with instead of 0 */
struct afs_addr_list *ret_alist;
struct afs_vldb_entry *ret_vldb;
+ char *ret_str;
};
struct afs_operation *op;
unsigned int server_index;
@@ -1373,6 +1374,7 @@ extern struct afs_addr_list *afs_vl_get_addrs_u(struct afs_vl_cursor *, const uu
extern struct afs_call *afs_vl_get_capabilities(struct afs_net *, struct afs_addr_cursor *,
struct key *, struct afs_vlserver *, unsigned int);
extern struct afs_addr_list *afs_yfsvl_get_endpoints(struct afs_vl_cursor *, const uuid_t *);
+extern char *afs_yfsvl_get_cell_name(struct afs_vl_cursor *);

/*
* vl_probe.c
diff --git a/fs/afs/protocol_yfs.h b/fs/afs/protocol_yfs.h
index 32be9c698348..b5bd03b1d3c7 100644
--- a/fs/afs/protocol_yfs.h
+++ b/fs/afs/protocol_yfs.h
@@ -8,7 +8,7 @@
#define YFS_FS_SERVICE 2500
#define YFS_CM_SERVICE 2501

-#define YFSCBMAX 1024
+#define YFSCBMAX 1024

enum YFS_CM_Operations {
YFSCBProbe = 206, /* probe client */
diff --git a/fs/afs/vlclient.c b/fs/afs/vlclient.c
index d0c85623ce8f..fd82850cd424 100644
--- a/fs/afs/vlclient.c
+++ b/fs/afs/vlclient.c
@@ -645,3 +645,114 @@ struct afs_addr_list *afs_yfsvl_get_endpoints(struct afs_vl_cursor *vc,
afs_make_call(&vc->ac, call, GFP_KERNEL);
return (struct afs_addr_list *)afs_wait_for_call_to_complete(call, &vc->ac);
}
+
+/*
+ * Deliver reply data to a YFSVL.GetCellName operation.
+ */
+static int afs_deliver_yfsvl_get_cell_name(struct afs_call *call)
+{
+ char *cell_name;
+ u32 namesz, paddedsz;
+ int ret;
+
+ _enter("{%u,%zu/%u}",
+ call->unmarshall, iov_iter_count(call->iter), call->count);
+
+ switch (call->unmarshall) {
+ case 0:
+ afs_extract_to_tmp(call);
+ call->unmarshall++;
+
+ /* Fall through - and extract the cell name length */
+ case 1:
+ ret = afs_extract_data(call, true);
+ if (ret < 0)
+ return ret;
+
+ namesz = ntohl(call->tmp);
+ if (namesz > AFS_MAXCELLNAME)
+ return afs_protocol_error(call, afs_eproto_cellname_len);
+ paddedsz = (namesz + 3) & ~3;
+ call->count = namesz;
+ call->count2 = paddedsz - namesz;
+
+ cell_name = kmalloc(namesz + 1, GFP_KERNEL);
+ if (!cell_name)
+ return -ENOMEM;
+ cell_name[namesz] = 0;
+ call->ret_str = cell_name;
+
+ afs_extract_begin(call, cell_name, namesz);
+ call->unmarshall++;
+
+ /* Fall through - and extract cell name */
+ case 2:
+ ret = afs_extract_data(call, true);
+ if (ret < 0)
+ return ret;
+
+ afs_extract_discard(call, call->count2);
+ call->unmarshall++;
+
+ /* Fall through - and extract padding */
+ case 3:
+ ret = afs_extract_data(call, false);
+ if (ret < 0)
+ return ret;
+
+ call->unmarshall++;
+ break;
+ }
+
+ _leave(" = 0 [done]");
+ return 0;
+}
+
+static void afs_destroy_yfsvl_get_cell_name(struct afs_call *call)
+{
+ kfree(call->ret_str);
+ afs_flat_call_destructor(call);
+}
+
+/*
+ * VL.GetCapabilities operation type
+ */
+static const struct afs_call_type afs_YFSVLGetCellName = {
+ .name = "YFSVL.GetCellName",
+ .op = afs_YFSVL_GetCellName,
+ .deliver = afs_deliver_yfsvl_get_cell_name,
+ .destructor = afs_destroy_yfsvl_get_cell_name,
+};
+
+/*
+ * Probe a volume server for the capabilities that it supports. This can
+ * return up to 196 words.
+ *
+ * We use this to probe for service upgrade to determine what the server at the
+ * other end supports.
+ */
+char *afs_yfsvl_get_cell_name(struct afs_vl_cursor *vc)
+{
+ struct afs_call *call;
+ struct afs_net *net = vc->cell->net;
+ __be32 *bp;
+
+ _enter("");
+
+ call = afs_alloc_flat_call(net, &afs_YFSVLGetCellName, 1 * 4, 0);
+ if (!call)
+ return ERR_PTR(-ENOMEM);
+
+ call->key = vc->key;
+ call->ret_str = NULL;
+ call->max_lifespan = AFS_VL_MAX_LIFESPAN;
+
+ /* marshall the parameters */
+ bp = call->request;
+ *bp++ = htonl(YVLGETCELLNAME);
+
+ /* Can't take a ref on server */
+ trace_afs_make_vl_call(call);
+ afs_make_call(&vc->ac, call, GFP_KERNEL);
+ return (char *)afs_wait_for_call_to_complete(call, &vc->ac);
+}
diff --git a/include/trace/events/afs.h b/include/trace/events/afs.h
index f4d66919fb22..f320b3ad54da 100644
--- a/include/trace/events/afs.h
+++ b/include/trace/events/afs.h
@@ -111,6 +111,7 @@ enum afs_vl_operation {
afs_VL_GetEntryByNameU = 527, /* AFS Get Vol Entry By Name operation ID */
afs_VL_GetAddrsU = 533, /* AFS Get FS server addresses */
afs_YFSVL_GetEndpoints = 64002, /* YFS Get FS & Vol server addresses */
+ afs_YFSVL_GetCellName = 64014, /* YFS Get actual cell name */
afs_VL_GetCapabilities = 65537, /* AFS Get VL server capabilities */
};

@@ -143,6 +144,7 @@ enum afs_eproto_cause {
afs_eproto_bad_status,
afs_eproto_cb_count,
afs_eproto_cb_fid_count,
+ afs_eproto_cellname_len,
afs_eproto_file_type,
afs_eproto_ibulkst_cb_count,
afs_eproto_ibulkst_count,
@@ -316,6 +318,7 @@ enum afs_cb_break_reason {
EM(afs_VL_GetEntryByNameU, "VL.GetEntryByNameU") \
EM(afs_VL_GetAddrsU, "VL.GetAddrsU") \
EM(afs_YFSVL_GetEndpoints, "YFSVL.GetEndpoints") \
+ EM(afs_YFSVL_GetCellName, "YFSVL.GetCellName") \
E_(afs_VL_GetCapabilities, "VL.GetCapabilities")

#define afs_edit_dir_ops \
@@ -345,6 +348,7 @@ enum afs_cb_break_reason {
EM(afs_eproto_bad_status, "BadStatus") \
EM(afs_eproto_cb_count, "CbCount") \
EM(afs_eproto_cb_fid_count, "CbFidCount") \
+ EM(afs_eproto_cellname_len, "CellNameLen") \
EM(afs_eproto_file_type, "FileTYpe") \
EM(afs_eproto_ibulkst_cb_count, "IBS.CbCount") \
EM(afs_eproto_ibulkst_count, "IBS.FidCount") \

Next message: David Howells: "[PATCH 18/27] afs: Detect cell aliases 1 - Cells with root volumes"
Previous message: David Howells: "[PATCH 16/27] afs: Retain more of the VLDB record for alias detection"
In reply to: David Howells: "[PATCH 16/27] afs: Retain more of the VLDB record for alias detection"
Next in thread: David Howells: "[PATCH 18/27] afs: Detect cell aliases 1 - Cells with root volumes"
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