s3:vfs_gpfs: Implement fallocate callback for GPFS

GPFS provides the gpfs_prealloc call. Implement the fallocate
callback with mode VFS_FALLOCATE_EXTEND_SIZE using this call.
There is no support for VFS_FALLOCATE_KEEP_SIZE, so report
this mode as not available.

4 files changed, 79 insertions, 0 deletions

diff --git a/docs-xml/manpages-3/vfs_gpfs.8.xml b/docs-xml/manpages-3/vfs_gpfs.8.xml
index 398dcff255..4ea8c4d046 100644
--- a/docs-xml/manpages-3/vfs_gpfs.8.xml
+++ b/docs-xml/manpages-3/vfs_gpfs.8.xml
@@ -268,6 +268,31 @@
 		</varlistentry>
 		<varlistentry>
 
+		<term>gpfs:prealloc = [ yes | no ]</term>
+		<listitem>
+		<para>
+		If set to yes the gpfs_prealloc function will be used in the
+		fallocate callback when appropriate. If set to no gpfs_prealloc
+		will not be used. In both cases the system and libc calls are
+		avoided.
+		</para>
+
+		<itemizedlist>
+		<listitem><para>
+		<command>yes (default)</command> - Use gpfs_prealloc for the
+		fallocate callback.
+		</para></listitem>
+		<listitem><para>
+		<command>no</command> - Do not use gpfs_prealloc for the
+		fallocate callback.
+		</para></listitem>
+		</itemizedlist>
+		</listitem>
+
+		</varlistentry>
+
+		<varlistentry>
+
 		<term>nfs4:mode = [ simple | special ]</term>
 		<listitem>
 		<para>
diff --git a/source3/modules/gpfs.c b/source3/modules/gpfs.c
index f17c6bb252..2cbf0b501a 100644
--- a/source3/modules/gpfs.c
+++ b/source3/modules/gpfs.c
@@ -35,6 +35,7 @@ static int (*gpfs_get_realfilename_path_fn)(char *pathname, char *filenamep,
 static int (*gpfs_set_winattrs_path_fn)(char *pathname, int flags, struct gpfs_winattr *attrs);
 static int (*gpfs_get_winattrs_path_fn)(char *pathname, struct gpfs_winattr *attrs);
 static int (*gpfs_get_winattrs_fn)(int fd, struct gpfs_winattr *attrs);
+static int (*gpfs_prealloc_fn)(int fd, gpfs_off64_t startOffset, gpfs_off64_t bytesToPrealloc);
 static int (*gpfs_ftruncate_fn)(int fd, gpfs_off64_t length);
 static int (*gpfs_lib_init_fn)(int flags);
 static int (*gpfs_quotactl_fn)(char *pathname, int cmd, int id, void *bufferP);
@@ -177,6 +178,16 @@ int smbd_fget_gpfs_winattrs(int fd, struct gpfs_winattr *attrs)
         return gpfs_get_winattrs_fn(fd, attrs);
 }
 
+int smbd_gpfs_prealloc(int fd, gpfs_off64_t start, gpfs_off64_t bytes)
+{
+	if (gpfs_prealloc_fn == NULL) {
+		errno = ENOSYS;
+		return -1;
+	}
+
+	return gpfs_prealloc_fn(fd, start, bytes);
+}
+
 int set_gpfs_winattrs(char *pathname,int flags,struct gpfs_winattr *attrs)
 {
 	if (gpfs_set_winattrs_path_fn == NULL) {
@@ -329,6 +340,7 @@ void init_gpfs(void)
 	init_gpfs_function(&gpfs_get_winattrs_path_fn,"gpfs_get_winattrs_path");
         init_gpfs_function(&gpfs_set_winattrs_path_fn,"gpfs_set_winattrs_path");
         init_gpfs_function(&gpfs_get_winattrs_fn,"gpfs_get_winattrs");
+	init_gpfs_function(&gpfs_prealloc_fn, "gpfs_prealloc");
 	init_gpfs_function(&gpfs_ftruncate_fn, "gpfs_ftruncate");
         init_gpfs_function(&gpfs_lib_init_fn,"gpfs_lib_init");
 	init_gpfs_function(&gpfs_quotactl_fn, "gpfs_quotactl");
diff --git a/source3/modules/vfs_gpfs.c b/source3/modules/vfs_gpfs.c
index 9597999232..65cd33a394 100644
--- a/source3/modules/vfs_gpfs.c
+++ b/source3/modules/vfs_gpfs.c
@@ -44,6 +44,7 @@ struct gpfs_config_data {
 	bool ftruncate;
 	bool getrealfilename;
 	bool dfreequota;
+	bool prealloc;
 };
 
 
@@ -1263,6 +1264,42 @@ static int vfs_gpfs_ntimes(struct vfs_handle_struct *handle,
 
 }
 
+int vfs_gpfs_fallocate(struct vfs_handle_struct *handle,
+		       struct files_struct *fsp, enum vfs_fallocate_mode mode,
+		       SMB_OFF_T offset, SMB_OFF_T len)
+{
+	int ret;
+	struct gpfs_config_data *config;
+
+	SMB_VFS_HANDLE_GET_DATA(handle, config,
+				struct gpfs_config_data,
+				return -1);
+
+	if (!config->prealloc) {
+		/* you should better not run fallocate() on GPFS at all */
+		errno = ENOTSUP;
+		return -1;
+	}
+
+	if (mode == VFS_FALLOCATE_KEEP_SIZE) {
+		DEBUG(10, ("Unsupported VFS_FALLOCATE_KEEP_SIZE\n"));
+		errno = ENOTSUP;
+		return -1;
+	}
+
+	ret = smbd_gpfs_prealloc(fsp->fh->fd, offset, len);
+
+	if (ret == -1 && errno != ENOSYS) {
+		DEBUG(0, ("GPFS prealloc failed: %s\n", strerror(errno)));
+	} else if (ret == -1 && errno == ENOSYS) {
+		DEBUG(10, ("GPFS prealloc not supported.\n"));
+	} else {
+		DEBUG(10, ("GPFS prealloc succeeded.\n"));
+	}
+
+	return ret;
+}
+
 static int vfs_gpfs_ftruncate(vfs_handle_struct *handle, files_struct *fsp,
 				SMB_OFF_T len)
 {
@@ -1390,6 +1427,9 @@ int vfs_gpfs_connect(struct vfs_handle_struct *handle, const char *service,
 	config->dfreequota = lp_parm_bool(SNUM(handle->conn), "gpfs",
 					  "dfreequota", false);
 
+	config->prealloc = lp_parm_bool(SNUM(handle->conn), "gpfs",
+				   "prealloc", true);
+
 	SMB_VFS_HANDLE_SET_DATA(handle, config,
 				NULL, struct gpfs_config_data,
 				return -1);
@@ -1582,6 +1622,7 @@ static struct vfs_fn_pointers vfs_gpfs_fns = {
 	.is_offline_fn = vfs_gpfs_is_offline,
 	.aio_force_fn = vfs_gpfs_aio_force,
 	.sendfile_fn = vfs_gpfs_sendfile,
+	.fallocate_fn = vfs_gpfs_fallocate,
 	.open_fn = vfs_gpfs_open,
 	.ftruncate_fn = vfs_gpfs_ftruncate
 };
diff --git a/source3/modules/vfs_gpfs.h b/source3/modules/vfs_gpfs.h
index 4a9528ae05..dfa4d4358f 100644
--- a/source3/modules/vfs_gpfs.h
+++ b/source3/modules/vfs_gpfs.h
@@ -33,6 +33,7 @@ int smbd_gpfs_get_realfilename_path(char *pathname, char *filenamep,
 int smbd_fget_gpfs_winattrs(int fd, struct gpfs_winattr *attrs);
 int get_gpfs_winattrs(char * pathname,struct gpfs_winattr *attrs);
 int set_gpfs_winattrs(char * pathname,int flags,struct gpfs_winattr *attrs);
+int smbd_gpfs_prealloc(int fd, gpfs_off64_t start, gpfs_off64_t bytes);
 int smbd_gpfs_ftruncate(int fd, gpfs_off64_t length);
 int get_gpfs_quota(const char *pathname, int type, int id,
 		   struct gpfs_quotaInfo *qi);