/* * ensure meta data operations are performed synchronously * * Copyright (C) Andrew Tridgell 2007 * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include "includes.h" /* Some filesystems (even some journaled filesystems) require that a fsync() be performed on many meta data operations to ensure that the operation is guaranteed to remain in the filesystem after a power failure. This is particularly important for some cluster filesystems which are participating in a node failover system with clustered Samba On those filesystems this module provides a way to perform those operations safely. most of the performance loss with this module is in fsync on close(). You can disable that with syncops:onclose = no that can be set either globally or per share. you can also disable the module completely for a service with syncops:disable = true */ struct syncops_config_data { bool onclose; bool disable; }; /* given a filename, find the parent directory */ static char *parent_dir(TALLOC_CTX *mem_ctx, const char *name) { const char *p = strrchr(name, '/'); if (p == NULL) { return talloc_strdup(mem_ctx, "."); } return talloc_strndup(mem_ctx, name, (p+1) - name); } /* fsync a directory by name */ static void syncops_sync_directory(const char *dname) { #ifdef O_DIRECTORY int fd = open(dname, O_DIRECTORY|O_RDONLY); if (fd != -1) { fsync(fd); close(fd); } #else DIR *d = opendir(dname); if (d != NULL) { fsync(dirfd(d)); closedir(d); } #endif } /* sync two meta data changes for 2 names */ static void syncops_two_names(const char *name1, const char *name2) { TALLOC_CTX *tmp_ctx = talloc_new(NULL); char *parent1, *parent2; parent1 = parent_dir(tmp_ctx, name1); parent2 = parent_dir(tmp_ctx, name2); if (!parent1 || !parent2) { talloc_free(tmp_ctx); return; } syncops_sync_directory(parent1); if (strcmp(parent1, parent2) != 0) { syncops_sync_directory(parent2); } talloc_free(tmp_ctx); } /* sync two meta data changes for 1 names */ static void syncops_name(const char *name) { char *parent; parent = parent_dir(NULL, name); if (parent) { syncops_sync_directory(parent); talloc_free(parent); } } /* sync two meta data changes for 1 names */ static void syncops_smb_fname(const struct smb_filename *smb_fname) { char *parent; parent = parent_dir(NULL, smb_fname->base_name); if (parent) { syncops_sync_directory(parent); talloc_free(parent); } } /* rename needs special handling, as we may need to fsync two directories */ static int syncops_rename(vfs_handle_struct *handle, const struct smb_filename *smb_fname_src, const struct smb_filename *smb_fname_dst) { int ret; struct syncops_config_data *config; SMB_VFS_HANDLE_GET_DATA(handle, config, struct syncops_config_data, return -1); ret = SMB_VFS_NEXT_RENAME(handle, smb_fname_src, smb_fname_dst); if (ret == 0 && !config->disable) { syncops_two_names(smb_fname_src->base_name, smb_fname_dst->base_name); } return ret; } /* handle the rest with a macro */ #define SYNCOPS_NEXT(op, fname, args) do { \ int ret; \ struct syncops_config_data *config; \ SMB_VFS_HANDLE_GET_DATA(handle, config, \ struct syncops_config_data, \ return -1); \ ret = SMB_VFS_NEXT_ ## op args; \ if (ret == 0 \ && !config->disable \ && fname) syncops_name(fname); \ return ret; \ } while (0) #define SYNCOPS_NEXT_SMB_FNAME(op, fname, args) do { \ int ret; \ struct syncops_config_data *config; \ SMB_VFS_HANDLE_GET_DATA(handle, config, \ struct syncops_config_data, \ return -1); \ ret = SMB_VFS_NEXT_ ## op args; \ if (ret == 0 \ && !config->disable \ && fname) syncops_smb_fname(fname); \ return ret; \ } while (0) static int syncops_symlink(vfs_handle_struct *handle, const char *oldname, const char *newname) { SYNCOPS_NEXT(SYMLINK, newname, (handle, oldname, newname)); } static int syncops_link(vfs_handle_struct *handle, const char *oldname, const char *newname) { SYNCOPS_NEXT(LINK, newname, (handle, oldname, newname)); } static int syncops_open(vfs_handle_struct *handle, struct smb_filename *smb_fname, files_struct *fsp, int flags, mode_t mode) { SYNCOPS_NEXT_SMB_FNAME(OPEN, (flags&O_CREAT?smb_fname:NULL), (handle, smb_fname, fsp, flags, mode)); } static int syncops_unlink(vfs_handle_struct *handle, const struct smb_filename *smb_fname) { SYNCOPS_NEXT_SMB_FNAME(UNLINK, smb_fname, (handle, smb_fname)); } static int syncops_mknod(vfs_handle_struct *handle, const char *fname, mode_t mode, SMB_DEV_T dev) { SYNCOPS_NEXT(MKNOD, fname, (handle, fname, mode, dev)); } static int syncops_mkdir(vfs_handle_struct *handle, const char *fname, mode_t mode) { SYNCOPS_NEXT(MKDIR, fname, (handle, fname, mode)); } static int syncops_rmdir(vfs_handle_struct *handle, const char *fname) { SYNCOPS_NEXT(RMDIR, fname, (handle, fname)); } /* close needs to be handled specially */ static int syncops_close(vfs_handle_struct *handle, files_struct *fsp) { struct syncops_config_data *config; SMB_VFS_HANDLE_GET_DATA(handle, config, struct syncops_config_data, return -1); if (fsp->can_write && config->onclose) { /* ideally we'd only do this if we have written some data, but there is no flag for that in fsp yet. */ fsync(fsp->fh->fd); } return SMB_VFS_NEXT_CLOSE(handle, fsp); } int syncops_connect(struct vfs_handle_struct *handle, const char *service, const char *user) { struct syncops_config_data *config; int ret = SMB_VFS_NEXT_CONNECT(handle, service, user); if (ret < 0) { return ret; } config = talloc_zero(handle->conn, struct syncops_config_data); if (!config) { SMB_VFS_NEXT_DISCONNECT(handle); DEBUG(0, ("talloc_zero() failed\n")); return -1; } config->onclose = lp_parm_bool(SNUM(handle->conn), "syncops", "onclose", true); config->disable = lp_parm_bool(SNUM(handle->conn), "syncops", "disable", false); SMB_VFS_HANDLE_SET_DATA(handle, config, NULL, struct syncops_config_data, return -1); return 0; } static struct vfs_fn_pointers vfs_syncops_fns = { .connect_fn = syncops_connect, .mkdir = syncops_mkdir, .rmdir = syncops_rmdir, .open = syncops_open, .rename = syncops_rename, .unlink = syncops_unlink, .symlink = syncops_symlink, .link = syncops_link, .mknod = syncops_mknod, .close_fn = syncops_close, }; NTSTATUS vfs_syncops_init(void) { NTSTATUS ret; ret = smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "syncops", &vfs_syncops_fns); if (!NT_STATUS_IS_OK(ret)) return ret; return ret; }