afs: Add an address list concept

Add an RCU replaceable address list structure to hold a list of server
addresses.  The list also holds the

To this end:

 (1) A cell's VL server address list can be loaded directly via insmod or
     echo to /proc/fs/afs/cells or dynamically from a DNS query for AFSDB
     or SRV records.

 (2) Anyone wanting to use a cell's VL server address must wait until the
     cell record comes online and has tried to obtain some addresses.

 (3) An FS server's address list, for the moment, has a single entry that
     is the key to the server list.  This will change in the future when a
     server is instead keyed on its UUID and the VL.GetAddrsU operation is
     used.

 (4) An 'address cursor' concept is introduced to handle iteration through
     the address list.  This is passed to the afs_make_call() as, in the
     future, stuff (such as abort code) that doesn't outlast the call will
     be returned in it.

In the future, we might want to annotate the list with information about
how each address fares.  We might then want to propagate such annotations
over address list replacement.

Whilst we're at it, we allow IPv6 addresses to be specified in
colon-delimited lists by enclosing them in square brackets.

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 60 insertions, 61 deletions

diff --git a/fs/afs/fsclient.c b/fs/afs/fsclient.c
index 680c02d510f7..6614d0a78daa 100644
--- a/fs/afs/fsclient.c
+++ b/fs/afs/fsclient.c
@@ -297,7 +297,7 @@ static const struct afs_call_type afs_RXFSFetchStatus = {
 /*
  * fetch the status information for a file
  */
-int afs_fs_fetch_file_status(struct afs_server *server,
+int afs_fs_fetch_file_status(struct afs_fs_cursor *fc,
 			     struct key *key,
 			     struct afs_vnode *vnode,
 			     struct afs_volsync *volsync,
@@ -325,9 +325,9 @@ int afs_fs_fetch_file_status(struct afs_server *server,
 	bp[2] = htonl(vnode->fid.vnode);
 	bp[3] = htonl(vnode->fid.unique);
 
-	call->cb_break = vnode->cb_break + server->cb_s_break;
-	afs_use_fs_server(call, server);
-	return afs_make_call(&server->addr, call, GFP_NOFS, async);
+	call->cb_break = vnode->cb_break + fc->server->cb_s_break;
+	afs_use_fs_server(call, fc->server);
+	return afs_make_call(&fc->ac, call, GFP_NOFS, async);
 }
 
 /*
@@ -502,7 +502,7 @@ static const struct afs_call_type afs_RXFSFetchData64 = {
 /*
  * fetch data from a very large file
  */
-static int afs_fs_fetch_data64(struct afs_server *server,
+static int afs_fs_fetch_data64(struct afs_fs_cursor *fc,
 			       struct key *key,
 			       struct afs_vnode *vnode,
 			       struct afs_read *req,
@@ -536,15 +536,15 @@ static int afs_fs_fetch_data64(struct afs_server *server,
 	bp[7] = htonl(lower_32_bits(req->len));
 
 	atomic_inc(&req->usage);
-	call->cb_break = vnode->cb_break + server->cb_s_break;
-	afs_use_fs_server(call, server);
-	return afs_make_call(&server->addr, call, GFP_NOFS, async);
+	call->cb_break = vnode->cb_break + fc->server->cb_s_break;
+	afs_use_fs_server(call, fc->server);
+	return afs_make_call(&fc->ac, call, GFP_NOFS, async);
 }
 
 /*
  * fetch data from a file
  */
-int afs_fs_fetch_data(struct afs_server *server,
+int afs_fs_fetch_data(struct afs_fs_cursor *fc,
 		      struct key *key,
 		      struct afs_vnode *vnode,
 		      struct afs_read *req,
@@ -557,7 +557,7 @@ int afs_fs_fetch_data(struct afs_server *server,
 	if (upper_32_bits(req->pos) ||
 	    upper_32_bits(req->len) ||
 	    upper_32_bits(req->pos + req->len))
-		return afs_fs_fetch_data64(server, key, vnode, req, async);
+		return afs_fs_fetch_data64(fc, key, vnode, req, async);
 
 	_enter("");
 
@@ -581,9 +581,9 @@ int afs_fs_fetch_data(struct afs_server *server,
 	bp[5] = htonl(lower_32_bits(req->len));
 
 	atomic_inc(&req->usage);
-	call->cb_break = vnode->cb_break + server->cb_s_break;
-	afs_use_fs_server(call, server);
-	return afs_make_call(&server->addr, call, GFP_NOFS, async);
+	call->cb_break = vnode->cb_break + fc->server->cb_s_break;
+	afs_use_fs_server(call, fc->server);
+	return afs_make_call(&fc->ac, call, GFP_NOFS, async);
 }
 
 /*
@@ -625,7 +625,7 @@ static const struct afs_call_type afs_RXFSCreateXXXX = {
 /*
  * create a file or make a directory
  */
-int afs_fs_create(struct afs_server *server,
+int afs_fs_create(struct afs_fs_cursor *fc,
 		  struct key *key,
 		  struct afs_vnode *vnode,
 		  const char *name,
@@ -677,8 +677,8 @@ int afs_fs_create(struct afs_server *server,
 	*bp++ = htonl(mode & S_IALLUGO); /* unix mode */
 	*bp++ = 0; /* segment size */
 
-	afs_use_fs_server(call, server);
-	return afs_make_call(&server->addr, call, GFP_NOFS, async);
+	afs_use_fs_server(call, fc->server);
+	return afs_make_call(&fc->ac, call, GFP_NOFS, async);
 }
 
 /*
@@ -717,7 +717,7 @@ static const struct afs_call_type afs_RXFSRemoveXXXX = {
 /*
  * remove a file or directory
  */
-int afs_fs_remove(struct afs_server *server,
+int afs_fs_remove(struct afs_fs_cursor *fc,
 		  struct key *key,
 		  struct afs_vnode *vnode,
 		  const char *name,
@@ -756,8 +756,8 @@ int afs_fs_remove(struct afs_server *server,
 		bp = (void *) bp + padsz;
 	}
 
-	afs_use_fs_server(call, server);
-	return afs_make_call(&server->addr, call, GFP_NOFS, async);
+	afs_use_fs_server(call, fc->server);
+	return afs_make_call(&fc->ac, call, GFP_NOFS, async);
 }
 
 /*
@@ -797,7 +797,7 @@ static const struct afs_call_type afs_RXFSLink = {
 /*
  * make a hard link
  */
-int afs_fs_link(struct afs_server *server,
+int afs_fs_link(struct afs_fs_cursor *fc,
 		struct key *key,
 		struct afs_vnode *dvnode,
 		struct afs_vnode *vnode,
@@ -840,8 +840,8 @@ int afs_fs_link(struct afs_server *server,
 	*bp++ = htonl(vnode->fid.vnode);
 	*bp++ = htonl(vnode->fid.unique);
 
-	afs_use_fs_server(call, server);
-	return afs_make_call(&server->addr, call, GFP_NOFS, async);
+	afs_use_fs_server(call, fc->server);
+	return afs_make_call(&fc->ac, call, GFP_NOFS, async);
 }
 
 /*
@@ -882,7 +882,7 @@ static const struct afs_call_type afs_RXFSSymlink = {
 /*
  * create a symbolic link
  */
-int afs_fs_symlink(struct afs_server *server,
+int afs_fs_symlink(struct afs_fs_cursor *fc,
 		   struct key *key,
 		   struct afs_vnode *vnode,
 		   const char *name,
@@ -943,8 +943,8 @@ int afs_fs_symlink(struct afs_server *server,
 	*bp++ = htonl(S_IRWXUGO); /* unix mode */
 	*bp++ = 0; /* segment size */
 
-	afs_use_fs_server(call, server);
-	return afs_make_call(&server->addr, call, GFP_NOFS, async);
+	afs_use_fs_server(call, fc->server);
+	return afs_make_call(&fc->ac, call, GFP_NOFS, async);
 }
 
 /*
@@ -986,7 +986,7 @@ static const struct afs_call_type afs_RXFSRename = {
 /*
  * create a symbolic link
  */
-int afs_fs_rename(struct afs_server *server,
+int afs_fs_rename(struct afs_fs_cursor *fc,
 		  struct key *key,
 		  struct afs_vnode *orig_dvnode,
 		  const char *orig_name,
@@ -1045,8 +1045,8 @@ int afs_fs_rename(struct afs_server *server,
 		bp = (void *) bp + n_padsz;
 	}
 
-	afs_use_fs_server(call, server);
-	return afs_make_call(&server->addr, call, GFP_NOFS, async);
+	afs_use_fs_server(call, fc->server);
+	return afs_make_call(&fc->ac, call, GFP_NOFS, async);
 }
 
 /*
@@ -1094,7 +1094,7 @@ static const struct afs_call_type afs_RXFSStoreData64 = {
 /*
  * store a set of pages to a very large file
  */
-static int afs_fs_store_data64(struct afs_server *server,
+static int afs_fs_store_data64(struct afs_fs_cursor *fc,
 			       struct afs_writeback *wb,
 			       pgoff_t first, pgoff_t last,
 			       unsigned offset, unsigned to,
@@ -1147,14 +1147,14 @@ static int afs_fs_store_data64(struct afs_server *server,
 	*bp++ = htonl(i_size >> 32);
 	*bp++ = htonl((u32) i_size);
 
-	afs_use_fs_server(call, server);
-	return afs_make_call(&server->addr, call, GFP_NOFS, async);
+	afs_use_fs_server(call, fc->server);
+	return afs_make_call(&fc->ac, call, GFP_NOFS, async);
 }
 
 /*
  * store a set of pages
  */
-int afs_fs_store_data(struct afs_server *server, struct afs_writeback *wb,
+int afs_fs_store_data(struct afs_fs_cursor *fc, struct afs_writeback *wb,
 		      pgoff_t first, pgoff_t last,
 		      unsigned offset, unsigned to,
 		      bool async)
@@ -1183,7 +1183,7 @@ int afs_fs_store_data(struct afs_server *server, struct afs_writeback *wb,
 	       (unsigned long long) i_size);
 
 	if (pos >> 32 || i_size >> 32 || size >> 32 || (pos + size) >> 32)
-		return afs_fs_store_data64(server, wb, first, last, offset, to,
+		return afs_fs_store_data64(fc, wb, first, last, offset, to,
 					   size, pos, i_size, async);
 
 	call = afs_alloc_flat_call(net, &afs_RXFSStoreData,
@@ -1221,8 +1221,8 @@ int afs_fs_store_data(struct afs_server *server, struct afs_writeback *wb,
 	*bp++ = htonl(size);
 	*bp++ = htonl(i_size);
 
-	afs_use_fs_server(call, server);
-	return afs_make_call(&server->addr, call, GFP_NOFS, async);
+	afs_use_fs_server(call, fc->server);
+	return afs_make_call(&fc->ac, call, GFP_NOFS, async);
 }
 
 /*
@@ -1279,7 +1279,7 @@ static const struct afs_call_type afs_RXFSStoreData64_as_Status = {
  * set the attributes on a very large file, using FS.StoreData rather than
  * FS.StoreStatus so as to alter the file size also
  */
-static int afs_fs_setattr_size64(struct afs_server *server, struct key *key,
+static int afs_fs_setattr_size64(struct afs_fs_cursor *fc, struct key *key,
 				 struct afs_vnode *vnode, struct iattr *attr,
 				 bool async)
 {
@@ -1319,15 +1319,15 @@ static int afs_fs_setattr_size64(struct afs_server *server, struct key *key,
 	*bp++ = htonl(attr->ia_size >> 32);	/* new file length */
 	*bp++ = htonl((u32) attr->ia_size);
 
-	afs_use_fs_server(call, server);
-	return afs_make_call(&server->addr, call, GFP_NOFS, async);
+	afs_use_fs_server(call, fc->server);
+	return afs_make_call(&fc->ac, call, GFP_NOFS, async);
 }
 
 /*
  * set the attributes on a file, using FS.StoreData rather than FS.StoreStatus
  * so as to alter the file size also
  */
-static int afs_fs_setattr_size(struct afs_server *server, struct key *key,
+static int afs_fs_setattr_size(struct afs_fs_cursor *fc, struct key *key,
 			       struct afs_vnode *vnode, struct iattr *attr,
 			       bool async)
 {
@@ -1340,8 +1340,7 @@ static int afs_fs_setattr_size(struct afs_server *server, struct key *key,
 
 	ASSERT(attr->ia_valid & ATTR_SIZE);
 	if (attr->ia_size >> 32)
-		return afs_fs_setattr_size64(server, key, vnode, attr,
-					     async);
+		return afs_fs_setattr_size64(fc, key, vnode, attr, async);
 
 	call = afs_alloc_flat_call(net, &afs_RXFSStoreData_as_Status,
 				   (4 + 6 + 3) * 4,
@@ -1367,15 +1366,15 @@ static int afs_fs_setattr_size(struct afs_server *server, struct key *key,
 	*bp++ = 0;				/* size of write */
 	*bp++ = htonl(attr->ia_size);		/* new file length */
 
-	afs_use_fs_server(call, server);
-	return afs_make_call(&server->addr, call, GFP_NOFS, async);
+	afs_use_fs_server(call, fc->server);
+	return afs_make_call(&fc->ac, call, GFP_NOFS, async);
 }
 
 /*
  * set the attributes on a file, using FS.StoreData if there's a change in file
  * size, and FS.StoreStatus otherwise
  */
-int afs_fs_setattr(struct afs_server *server, struct key *key,
+int afs_fs_setattr(struct afs_fs_cursor *fc, struct key *key,
 		   struct afs_vnode *vnode, struct iattr *attr,
 		   bool async)
 {
@@ -1384,8 +1383,7 @@ int afs_fs_setattr(struct afs_server *server, struct key *key,
 	__be32 *bp;
 
 	if (attr->ia_valid & ATTR_SIZE)
-		return afs_fs_setattr_size(server, key, vnode, attr,
-					   async);
+		return afs_fs_setattr_size(fc, key, vnode, attr, async);
 
 	_enter(",%x,{%x:%u},,",
 	       key_serial(key), vnode->fid.vid, vnode->fid.vnode);
@@ -1409,8 +1407,8 @@ int afs_fs_setattr(struct afs_server *server, struct key *key,
 
 	xdr_encode_AFS_StoreStatus(&bp, attr);
 
-	afs_use_fs_server(call, server);
-	return afs_make_call(&server->addr, call, GFP_NOFS, async);
+	afs_use_fs_server(call, fc->server);
+	return afs_make_call(&fc->ac, call, GFP_NOFS, async);
 }
 
 /*
@@ -1607,7 +1605,7 @@ static const struct afs_call_type afs_RXFSGetVolumeStatus = {
 /*
  * fetch the status of a volume
  */
-int afs_fs_get_volume_status(struct afs_server *server,
+int afs_fs_get_volume_status(struct afs_fs_cursor *fc,
 			     struct key *key,
 			     struct afs_vnode *vnode,
 			     struct afs_volume_status *vs,
@@ -1640,8 +1638,8 @@ int afs_fs_get_volume_status(struct afs_server *server,
 	bp[0] = htonl(FSGETVOLUMESTATUS);
 	bp[1] = htonl(vnode->fid.vid);
 
-	afs_use_fs_server(call, server);
-	return afs_make_call(&server->addr, call, GFP_NOFS, async);
+	afs_use_fs_server(call, fc->server);
+	return afs_make_call(&fc->ac, call, GFP_NOFS, async);
 }
 
 /*
@@ -1696,7 +1694,7 @@ static const struct afs_call_type afs_RXFSReleaseLock = {
 /*
  * get a lock on a file
  */
-int afs_fs_set_lock(struct afs_server *server,
+int afs_fs_set_lock(struct afs_fs_cursor *fc,
 		    struct key *key,
 		    struct afs_vnode *vnode,
 		    afs_lock_type_t type,
@@ -1723,14 +1721,14 @@ int afs_fs_set_lock(struct afs_server *server,
 	*bp++ = htonl(vnode->fid.unique);
 	*bp++ = htonl(type);
 
-	afs_use_fs_server(call, server);
-	return afs_make_call(&server->addr, call, GFP_NOFS, async);
+	afs_use_fs_server(call, fc->server);
+	return afs_make_call(&fc->ac, call, GFP_NOFS, async);
 }
 
 /*
  * extend a lock on a file
  */
-int afs_fs_extend_lock(struct afs_server *server,
+int afs_fs_extend_lock(struct afs_fs_cursor *fc,
 		       struct key *key,
 		       struct afs_vnode *vnode,
 		       bool async)
@@ -1755,14 +1753,14 @@ int afs_fs_extend_lock(struct afs_server *server,
 	*bp++ = htonl(vnode->fid.vnode);
 	*bp++ = htonl(vnode->fid.unique);
 
-	afs_use_fs_server(call, server);
-	return afs_make_call(&server->addr, call, GFP_NOFS, async);
+	afs_use_fs_server(call, fc->server);
+	return afs_make_call(&fc->ac, call, GFP_NOFS, async);
 }
 
 /*
  * release a lock on a file
  */
-int afs_fs_release_lock(struct afs_server *server,
+int afs_fs_release_lock(struct afs_fs_cursor *fc,
 			struct key *key,
 			struct afs_vnode *vnode,
 			bool async)
@@ -1787,8 +1785,8 @@ int afs_fs_release_lock(struct afs_server *server,
 	*bp++ = htonl(vnode->fid.vnode);
 	*bp++ = htonl(vnode->fid.unique);
 
-	afs_use_fs_server(call, server);
-	return afs_make_call(&server->addr, call, GFP_NOFS, async);
+	afs_use_fs_server(call, fc->server);
+	return afs_make_call(&fc->ac, call, GFP_NOFS, async);
 }
 
 /*
@@ -1812,6 +1810,7 @@ static const struct afs_call_type afs_RXFSGiveUpAllCallBacks = {
  * Flush all the callbacks we have on a server.
  */
 int afs_fs_give_up_all_callbacks(struct afs_server *server,
+				 struct afs_addr_cursor *ac,
 				 struct key *key,
 				 bool async)
 {
@@ -1831,5 +1830,5 @@ int afs_fs_give_up_all_callbacks(struct afs_server *server,
 	*bp++ = htonl(FSGIVEUPALLCALLBACKS);
 
 	/* Can't take a ref on server */
-	return afs_make_call(&server->addr, call, GFP_NOFS, async);
+	return afs_make_call(ac, call, GFP_NOFS, async);
 }