deleg: use SETATTR for OPEN4_CREATE

prevent an OPEN with OPEN4_CREATE from breaking a write delegation by sending a SETATTR instead
moved static function remove_unsupported_attrs() from setattr.c to nfs41_superblock_supported_attrs() in nfs41_superblock.c, now used by both setattr.c and delegation.c

Signed-off-by: Casey Bodley <cbodley@citi.umich.edu>

daemon/delegation.c

@@ -215,10 +215,6 @@ static bool_t delegation_compatible(
     IN uint32_t access,
     IN uint32_t deny)
 {
-    /* TODO: allow write delegation to handle OPEN4_CREATE */
-    if (create == OPEN4_CREATE)
-        return FALSE;
-
     switch (type) {
     case OPEN_DELEGATE_WRITE:
         /* An OPEN_DELEGATE_WRITE delegation allows the client to handle,
@@ -229,6 +225,8 @@ static bool_t delegation_compatible(
         /* An OPEN_DELEGATE_READ delegation allows a client to handle,
          * on its own, requests to open a file for reading that do not
          * deny OPEN4_SHARE_ACCESS_READ access to others. */
+        if (create == OPEN4_CREATE)
+            return FALSE;
         if (access & OPEN4_SHARE_ACCESS_WRITE || deny & OPEN4_SHARE_DENY_READ)
             return FALSE;
         return TRUE;
@@ -258,16 +256,45 @@ static int delegation_find(
     return status;
 }
 
+static int delegation_truncate(
+    IN nfs41_delegation_state *deleg,
+    IN nfs41_client *client,
+    IN stateid_arg *stateid,
+    IN uint32_t mode,
+    IN nfs41_file_info *info)
+{
+    nfs41_superblock *superblock = deleg->file.fh.superblock;
+
+    /* use SETATTR to truncate the file */
+    info->attrmask.arr[0] = FATTR4_WORD0_SIZE;
+    info->attrmask.arr[1] = FATTR4_WORD1_MODE |
+        FATTR4_WORD1_TIME_CREATE | FATTR4_WORD1_TIME_MODIFY_SET;
+    info->attrmask.count = 2;
+
+    info->size = 0;
+    info->mode = mode;
+    get_nfs_time(&info->time_create);
+    get_nfs_time(&info->time_modify);
+    info->time_delta = &superblock->time_delta;
+
+    /* mask out unsupported attributes */
+    nfs41_superblock_supported_attrs(superblock, &info->attrmask);
+
+    return nfs41_setattr(client->session, &deleg->file, stateid, info);
+}
+
 int nfs41_delegate_open(
     IN nfs41_client *client,
     IN nfs41_path_fh *file,
     IN uint32_t create,
+    IN uint32_t mode,
     IN uint32_t access,
     IN uint32_t deny,
     OUT nfs41_delegation_state **deleg_out,
     OUT nfs41_file_info *info)
 {
     nfs41_delegation_state *deleg;
+    stateid_arg stateid;
     int status;
 
     /* search for a delegation with this filehandle */
@@ -290,6 +317,11 @@ int nfs41_delegate_open(
 #else
         status = NFS4ERR_BADHANDLE;
 #endif
+    } else if (create == OPEN4_CREATE) {
+        /* copy the stateid for SETATTR */
+        stateid.open = NULL;
+        stateid.type = STATEID_DELEG_FILE;
+        memcpy(&stateid.stateid, &deleg->state.stateid, sizeof(stateid4));
     }
     ReleaseSRWLockExclusive(&deleg->lock);
 
@@ -298,6 +330,13 @@ int nfs41_delegate_open(
     if (status)
         goto out_deleg;
 
+    if (create == OPEN4_CREATE) {
+        /* write delegations allow us to simulate OPEN4_CREATE with SETATTR */
+        status = delegation_truncate(deleg, client, &stateid, mode, info);
+        if (status)
+            goto out_deleg;
+    }
+
     /* TODO: check access against deleg->state.permissions or send ACCESS */
 
     *deleg_out = deleg;

daemon/delegation.h

@@ -53,6 +53,7 @@ int nfs41_delegate_open(
     IN nfs41_client *client,
     IN nfs41_path_fh *file,
     IN uint32_t create,
+    IN uint32_t mode,
     IN uint32_t access,
     IN uint32_t deny,
     OUT nfs41_delegation_state **deleg_out,

daemon/nfs41.h

@@ -412,6 +412,10 @@ int nfs41_superblock_for_fh(
     IN const nfs41_fh *parent OPTIONAL,
     OUT nfs41_path_fh *file);
 
+void nfs41_superblock_supported_attrs(
+    IN nfs41_superblock *superblock,
+    IN OUT bitmap4 *attrs);
+
 void nfs41_superblock_space_changed(
     IN nfs41_superblock *superblock);
 

daemon/nfs41_superblock.c

@@ -247,6 +247,22 @@ out:
     return status;
 }
 
+void nfs41_superblock_supported_attrs(
+    IN nfs41_superblock *superblock,
+    IN OUT bitmap4 *attrs)
+{
+    uint32_t i, count = 0;
+
+    AcquireSRWLockShared(&superblock->lock);
+    for (i = 0; i < 3; i++) {
+        attrs->arr[i] &= superblock->supported_attrs.arr[i];
+        if (attrs->arr[i])
+            count = i+1;
+    }
+    attrs->count = min(attrs->count, count);
+    ReleaseSRWLockShared(&superblock->lock);
+}
+
 void nfs41_superblock_space_changed(
     IN nfs41_superblock *superblock)
 {

daemon/open.c

@@ -233,8 +233,9 @@ static int open_or_delegate(
     int status;
 
     /* check for existing delegation */
-    status = nfs41_delegate_open(state->session->client, &state->file, create,
+    status = nfs41_delegate_open(state->session->client, &state->file,
-        state->share_access, state->share_deny, &state->delegation.state, info);
+        create, mode, state->share_access, state->share_deny,
+        &state->delegation.state, info);
 
     /* get an open stateid if we have no delegation stateid */
     if (status)

daemon/setattr.c

@@ -65,26 +65,6 @@ out_free:
     goto out;
 }
 
-static void remove_unsupported_attrs(
-    IN const bitmap4 *supported_attrs,
-    IN OUT bitmap4 *attrs)
-{
-    uint32_t i, count = 0;
-    dprintf(3, "remove_unsupported_attrs\n");
-    for (i = 0; i < 3; i++) {
-        dprintf(3, "\tmask[%d] = %12u", i, attrs->arr[i]);
-        dprintf(3, " & %12u", supported_attrs->arr[i]);
-
-        attrs->arr[i] &= supported_attrs->arr[i];
-        if (attrs->arr[i])
-            count = i+1;
-
-        dprintf(3, " = %12d\n", attrs->arr[i]);
-    }
-    attrs->count = min(attrs->count, count);
-    dprintf(3, "\tcount   = %d\n", attrs->count);
-}
-
 static int handle_nfs41_setattr(setattr_upcall_args *args)
 {
     PFILE_BASIC_INFO basic_info = (PFILE_BASIC_INFO)args->buf;
@@ -136,10 +116,8 @@ static int handle_nfs41_setattr(setattr_upcall_args *args)
         info.attrmask.count = 2;
     }
 
-    /* only ask for attributes that are supported by the filesystem */
+    /* mask out unsupported attributes */
-    AcquireSRWLockShared(&superblock->lock);
+    nfs41_superblock_supported_attrs(superblock, &info.attrmask);
-    remove_unsupported_attrs(&superblock->supported_attrs, &info.attrmask);
-    ReleaseSRWLockShared(&superblock->lock);
 
     if (!info.attrmask.count)
         goto out;