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Diffstat (limited to 'source3/modules/vfs_prealloc.c')
| -rw-r--r-- | source3/modules/vfs_prealloc.c | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/source3/modules/vfs_prealloc.c b/source3/modules/vfs_prealloc.c new file mode 100644 index 0000000000..2a06e3d81b --- /dev/null +++ b/source3/modules/vfs_prealloc.c @@ -0,0 +1,220 @@ +/* + * 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" + +/* 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, SMB_OFF_T size) +{ +#ifndef HAVE_GPFS + lock_type fl = {0}; + int err; + + 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) +{ + module_debug = lp_parm_int(SNUM(handle->conn), + MODULE, "debug", 100); + + return SMB_VFS_NEXT_CONNECT(handle, service, user); +} + +static int prealloc_open(vfs_handle_struct* handle, + const char * fname, + files_struct * fsp, + int flags, + mode_t mode) +{ + int fd; + off64_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(fname, '.'); + 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, 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)) { + SMB_OFF_T * psize; + + psize = VFS_ADD_FSP_EXTENSION(handle, fsp, SMB_OFF_T); + if (psize == NULL || *psize == -1) { + return fd; + } + + DEBUG(module_debug, + ("%s: preallocating %s (fd=%d) to %lld bytes\n", + MODULE, 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, fname)); + return SMB_VFS_NEXT_OPEN(handle, fname, fsp, flags, mode); +} + +static int prealloc_ftruncate(vfs_handle_struct * handle, + files_struct * fsp, + SMB_OFF_T offset) +{ + SMB_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 vfs_op_tuple prealloc_op_tuples[] = { + {SMB_VFS_OP(prealloc_open), SMB_VFS_OP_OPEN, SMB_VFS_LAYER_TRANSPARENT}, + {SMB_VFS_OP(prealloc_ftruncate), SMB_VFS_OP_FTRUNCATE, SMB_VFS_LAYER_TRANSPARENT}, + {SMB_VFS_OP(prealloc_connect), SMB_VFS_OP_CONNECT, SMB_VFS_LAYER_TRANSPARENT}, + {NULL, SMB_VFS_OP_NOOP, SMB_VFS_LAYER_NOOP} +}; + +NTSTATUS vfs_prealloc_init(void); +NTSTATUS vfs_prealloc_init(void) +{ + return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, + MODULE, prealloc_op_tuples); +} |