diff options
Diffstat (limited to 'source3/modules/vfs_commit.c')
| -rw-r--r-- | source3/modules/vfs_commit.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/source3/modules/vfs_commit.c b/source3/modules/vfs_commit.c new file mode 100644 index 00000000000..9d817c017d2 --- /dev/null +++ b/source3/modules/vfs_commit.c @@ -0,0 +1,189 @@ +/* + * 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 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" + +/* Commit data module. + * + * The purpose of this module is to flush data to disk at regular intervals, + * just like the NFS commit operation. There's two rationales for this. First, + * it minimises the data loss in case of a power outage without incurring + * the poor performance of synchronous I/O. Second, a steady flush rate + * can produce better throughput than suddenly dumping massive amounts of + * writes onto a disk. + * + * Tunables: + * + * commit: dthresh Amount of dirty data that can accumulate + * before we commit (sync) it. + * + * commit: debug Debug level at which to emit messages. + * + */ + +#define MODULE "commit" + +static int module_debug; + +struct commit_info +{ + SMB_OFF_T dbytes; /* Dirty (uncommitted) bytes */ + SMB_OFF_T dthresh; /* Dirty data threshold */ +}; + +static void commit_all( + struct vfs_handle_struct * handle, + files_struct * fsp) +{ + struct commit_info *c; + + if ((c = VFS_FETCH_FSP_EXTENSION(handle, fsp))) { + if (c->dbytes) { + DEBUG(module_debug, + ("%s: flushing %lu dirty bytes\n", + MODULE, (unsigned long)c->dbytes)); + + fdatasync(fsp->fh->fd); + c->dbytes = 0; + } + } +} + +static void commit( + struct vfs_handle_struct * handle, + files_struct * fsp, + ssize_t last_write) +{ + struct commit_info *c; + + if ((c = VFS_FETCH_FSP_EXTENSION(handle, fsp))) { + + if (last_write > 0) { + c->dbytes += last_write; + } + + if (c->dbytes > c->dthresh) { + DEBUG(module_debug, + ("%s: flushing %lu dirty bytes\n", + MODULE, (unsigned long)c->dbytes)); + + fdatasync(fsp->fh->fd); + c->dbytes = 0; + } + } +} + +static int commit_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 commit_open( + vfs_handle_struct * handle, + const char * fname, + files_struct * fsp, + int flags, + mode_t mode) +{ + SMB_OFF_T dthresh; + + /* Don't bother with read-only files. */ + if ((flags & O_ACCMODE) == O_RDONLY) { + return SMB_VFS_NEXT_OPEN(handle, fname, fsp, flags, mode); + } + + dthresh = conv_str_size(lp_parm_const_string(SNUM(handle->conn), + MODULE, "dthresh", NULL)); + + if (dthresh > 0) { + struct commit_info * c; + c = VFS_ADD_FSP_EXTENSION(handle, fsp, struct commit_info); + if (c) { + c->dthresh = dthresh; + c->dbytes = 0; + } + } + + return SMB_VFS_NEXT_OPEN(handle, fname, fsp, flags, mode); +} + +static ssize_t commit_write( + vfs_handle_struct * handle, + files_struct * fsp, + int fd, + void * data, + size_t count) +{ + ssize_t ret; + + ret = SMB_VFS_NEXT_WRITE(handle, fsp, fd, data, count); + commit(handle, fsp, ret); + + return ret; +} + +static ssize_t commit_pwrite( + vfs_handle_struct * handle, + files_struct * fsp, + int fd, + void * data, + size_t count, + SMB_OFF_T offset) +{ + ssize_t ret; + + ret = SMB_VFS_NEXT_PWRITE(handle, fsp, fd, data, count, offset); + commit(handle, fsp, ret); + + return ret; +} + +static ssize_t commit_close( + vfs_handle_struct * handle, + files_struct * fsp, + int fd) +{ + commit_all(handle, fsp); + return SMB_VFS_NEXT_CLOSE(handle, fsp, fd); +} + +static vfs_op_tuple commit_ops [] = +{ + {SMB_VFS_OP(commit_open), + SMB_VFS_OP_OPEN, SMB_VFS_LAYER_TRANSPARENT}, + {SMB_VFS_OP(commit_close), + SMB_VFS_OP_CLOSE, SMB_VFS_LAYER_TRANSPARENT}, + {SMB_VFS_OP(commit_write), + SMB_VFS_OP_WRITE, SMB_VFS_LAYER_TRANSPARENT}, + {SMB_VFS_OP(commit_pwrite), + SMB_VFS_OP_PWRITE, SMB_VFS_LAYER_TRANSPARENT}, + {SMB_VFS_OP(commit_connect), + SMB_VFS_OP_CONNECT, SMB_VFS_LAYER_TRANSPARENT}, + + {SMB_VFS_OP(NULL), SMB_VFS_OP_NOOP, SMB_VFS_LAYER_NOOP} +}; + +NTSTATUS vfs_commit_init(void) +{ + return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, MODULE, commit_ops); +} + |