/* * XFS preallocation support module. * * Copyright (c) James Peach 2006 * * 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 3 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, see <http://www.gnu.org/licenses/>. */ #include "includes.h" #include "system/filesys.h" #include "smbd/smbd.h" /* Extent preallocation module. * * The purpose of this module is to preallocate space on the filesystem when * we have a good idea of how large files are supposed to be. This lets writes * proceed without having to allocate new extents and results in better file * layouts on disk. * * Currently only implemented for XFS. This module is based on an original idea * and implementation by Sebastian Brings. * * Tunables. * * prealloc: <ext> Number of bytes to preallocate for a file with * the matching extension. * prealloc:debug Debug level at which to emit messages. * * Example. * * prealloc:mpeg = 500M # Preallocate *.mpeg to 500 MiB. */ #ifdef HAVE_XFS_LIBXFS_H #include <xfs/libxfs.h> #define lock_type xfs_flock64_t #else #define lock_type struct flock64 #endif #ifdef HAVE_GPFS #include "gpfs_gpl.h" #endif #define MODULE "prealloc" static int module_debug; static int preallocate_space(int fd, off_t size) { int err; #ifndef HAVE_GPFS lock_type fl = {0}; if (size <= 0) { return 0; } fl.l_whence = SEEK_SET; fl.l_start = 0; fl.l_len = size; /* IMPORTANT: We use RESVSP because we want the extents to be * allocated, but we don't want the allocation to show up in * st_size or persist after the close(2). */ #if defined(XFS_IOC_RESVSP64) /* On Linux this comes in via libxfs.h. */ err = xfsctl(NULL, fd, XFS_IOC_RESVSP64, &fl); #elif defined(F_RESVSP64) /* On IRIX, this comes from fcntl.h. */ err = fcntl(fd, F_RESVSP64, &fl); #else err = -1; errno = ENOSYS; #endif #else /* GPFS uses completely different interface */ err = gpfs_prealloc(fd, (gpfs_off64_t)0, (gpfs_off64_t)size); #endif if (err) { DEBUG(module_debug, ("%s: preallocate failed on fd=%d size=%lld: %s\n", MODULE, fd, (long long)size, strerror(errno))); } return err; } static int prealloc_connect( struct vfs_handle_struct * handle, const char * service, const char * user) { int ret = SMB_VFS_NEXT_CONNECT(handle, service, user); if (ret < 0) { return ret; } module_debug = lp_parm_int(SNUM(handle->conn), MODULE, "debug", 100); return 0; } static int prealloc_open(vfs_handle_struct* handle, struct smb_filename *smb_fname, files_struct * fsp, int flags, mode_t mode) { int fd; off_t size = 0; const char * dot; char fext[10]; if (!(flags & (O_CREAT|O_TRUNC))) { /* Caller is not intending to rewrite the file. Let's not mess * with the allocation in this case. */ goto normal_open; } *fext = '\0'; dot = strrchr(smb_fname->base_name, '.'); if (dot && *++dot) { if (strlen(dot) < sizeof(fext)) { strncpy(fext, dot, sizeof(fext)); strnorm(fext, CASE_LOWER); } } if (*fext == '\0') { goto normal_open; } /* Syntax for specifying preallocation size is: * MODULE: <extension> = <size> * where * <extension> is the file extension in lower case * <size> is a size like 10, 10K, 10M */ size = conv_str_size(lp_parm_const_string(SNUM(handle->conn), MODULE, fext, NULL)); if (size <= 0) { /* No need to preallocate this file. */ goto normal_open; } fd = SMB_VFS_NEXT_OPEN(handle, smb_fname, fsp, flags, mode); if (fd < 0) { return fd; } /* Prellocate only if the file is being created or replaced. Note that * Samba won't ever pass down O_TRUNC, which is why we have to handle * truncate calls specially. */ if ((flags & O_CREAT) || (flags & O_TRUNC)) { off_t * psize; psize = VFS_ADD_FSP_EXTENSION(handle, fsp, off_t, NULL); if (psize == NULL || *psize == -1) { return fd; } DEBUG(module_debug, ("%s: preallocating %s (fd=%d) to %lld bytes\n", MODULE, smb_fname_str_dbg(smb_fname), fd, (long long)size)); *psize = size; if (preallocate_space(fd, *psize) < 0) { VFS_REMOVE_FSP_EXTENSION(handle, fsp); } } return fd; normal_open: /* We are not creating or replacing a file. Skip the * preallocation. */ DEBUG(module_debug, ("%s: skipping preallocation for %s\n", MODULE, smb_fname_str_dbg(smb_fname))); return SMB_VFS_NEXT_OPEN(handle, smb_fname, fsp, flags, mode); } static int prealloc_ftruncate(vfs_handle_struct * handle, files_struct * fsp, off_t offset) { off_t *psize; int ret = SMB_VFS_NEXT_FTRUNCATE(handle, fsp, offset); /* Maintain the allocated space even in the face of truncates. */ if ((psize = VFS_FETCH_FSP_EXTENSION(handle, fsp))) { preallocate_space(fsp->fh->fd, *psize); } return ret; } static struct vfs_fn_pointers prealloc_fns = { .open_fn = prealloc_open, .ftruncate_fn = prealloc_ftruncate, .connect_fn = prealloc_connect, }; NTSTATUS vfs_prealloc_init(void); NTSTATUS vfs_prealloc_init(void) { return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, MODULE, &prealloc_fns); }