libnfs.c: Support use of O_TRUNC with nfs_create

Simplify usage for application programmers by supporting the use of
O_TRUNC with nfs_create.

Signed-off-by: Ross Lagerwall <rosslagerwall@gmail.com>

diff --git a/include/nfsc/libnfs.h b/include/nfsc/libnfs.h
index ff0d4e4ad4b4bcdfae7f38a9c502e0389faa7e3a..8ac6b94d3fc9de08f0654f2f2074b6fdb2ce23ea 100644 (file)
--- a/include/nfsc/libnfs.h
+++ b/include/nfsc/libnfs.h
@@ -689,6 +689,7 @@ EXTERN int nfs_creat(struct nfs_context *nfs, const char *path, int mode, struct
  * O_APPEND
  * O_SYNC
  * O_EXCL
+ * O_TRUNC
  *
  * Function returns
  *  0 : The operation was initiated. Once the operation finishes, the callback will be invoked.

diff --git a/lib/libnfs.c b/lib/libnfs.c
index 459ebd7bf80e3e18e73dd24087a5653051dd6b81..2f2dc4faab43a3564b43424539d79fc50d03f991 100644 (file)
--- a/lib/libnfs.c
+++ b/lib/libnfs.c
@@ -696,6 +696,16 @@ static void free_nfs_cb_data(struct nfs_cb_data *data)
        free(data);
 }
 
+static void free_nfsfh(struct nfsfh *nfsfh)
+{
+       if (nfsfh->fh.data.data_val != NULL) {
+               free(nfsfh->fh.data.data_val);
+               nfsfh->fh.data.data_val = NULL;
+       }
+       free(nfsfh->ra.buf);
+       free(nfsfh);
+}
+
 
 static void nfs_mount_10_cb(struct rpc_context *rpc, int status, void *command_data, void *private_data)
 {
@@ -2135,13 +2145,7 @@ int nfs_write_async(struct nfs_context *nfs, struct nfsfh *nfsfh, uint64_t count
 
 int nfs_close_async(struct nfs_context *nfs, struct nfsfh *nfsfh, nfs_cb cb, void *private_data)
 {
-       if (nfsfh->fh.data.data_val != NULL){
-               free(nfsfh->fh.data.data_val);
-               nfsfh->fh.data.data_val = NULL;
-       }
-       free(nfsfh->ra.buf);
-       free(nfsfh);
-
+       free_nfsfh(nfsfh);
        cb(0, nfs, NULL, private_data);
        return 0;
 };
@@ -2541,6 +2545,41 @@ static void free_create_cb_data(void *ptr)
        free(data);
 }
 
+static void nfs_create_trunc_cb(struct rpc_context *rpc, int status, void *command_data, void *private_data)
+{
+       struct nfs_cb_data *data = private_data;
+       struct nfs_context *nfs = data->nfs;
+       struct nfsfh *nfsfh;
+       SETATTR3res *res;
+
+       assert(rpc->magic == RPC_CONTEXT_MAGIC);
+
+       if (status == RPC_STATUS_ERROR) {
+               data->cb(-EFAULT, nfs, command_data, data->private_data);
+               free_nfs_cb_data(data);
+               free_nfsfh(nfsfh);
+               return;
+       }
+       if (status == RPC_STATUS_CANCEL) {
+               data->cb(-EINTR, nfs, "Command was cancelled", data->private_data);
+               free_nfs_cb_data(data);
+               free_nfsfh(nfsfh);
+               return;
+       }
+
+       res = command_data;
+       if (res->status != NFS3_OK) {
+               rpc_set_error(nfs->rpc, "NFS: Setattr failed with %s(%d)", nfsstat3_to_str(res->status), nfsstat3_to_errno(res->status));
+               data->cb(nfsstat3_to_errno(res->status), nfs, rpc_get_error(nfs->rpc), data->private_data);
+               free_nfs_cb_data(data);
+               free_nfsfh(nfsfh);
+               return;
+       }
+
+       data->cb(0, nfs, data->nfsfh, data->private_data);
+       free_nfs_cb_data(data);
+}
+
 static void nfs_create_2_cb(struct rpc_context *rpc, int status, void *command_data, void *private_data)
 {
        LOOKUP3res *res;
@@ -2593,6 +2632,30 @@ static void nfs_create_2_cb(struct rpc_context *rpc, int status, void *command_d
        nfsfh->fh.data.data_val = malloc(nfsfh->fh.data.data_len);
        memcpy(nfsfh->fh.data.data_val, res->LOOKUP3res_u.resok.object.data.data_val, nfsfh->fh.data.data_len);
 
+       /* Try to truncate it if we were requested to */
+       if (cb_data->flags & O_TRUNC) {
+               SETATTR3args args;
+
+               data->nfsfh = nfsfh;
+
+               memset(&args, 0, sizeof(SETATTR3args));
+               args.object = nfsfh->fh;
+               args.new_attributes.size.set_it = 1;
+               args.new_attributes.size.set_size3_u.size = 0;
+
+               if (rpc_nfs3_setattr_async(nfs->rpc, nfs_create_trunc_cb,
+                               &args, data) != 0) {
+                       rpc_set_error(nfs->rpc, "RPC error: Failed to send "
+                               "SETATTR call for %s", data->path);
+                       data->cb(-ENOMEM, nfs, rpc_get_error(nfs->rpc),
+                               data->private_data);
+                       free_nfs_cb_data(data);
+                       free_nfsfh(nfsfh);
+                       return;
+               }
+               return;
+       }
+
        data->cb(0, nfs, nfsfh, data->private_data);
        free_nfs_cb_data(data);
 }