mirror of
https://github.com/samba-team/samba.git
synced 2024-12-23 17:34:34 +03:00
391a72a95f
Jeremy.
(This used to be commit 97dca242a9
)
599 lines
16 KiB
C
599 lines
16 KiB
C
/*
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Unix SMB/Netbios implementation.
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Version 1.9.
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read/write to a files_struct
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Copyright (C) Andrew Tridgell 1992-1998
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "includes.h"
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static BOOL setup_write_cache(files_struct *, SMB_OFF_T);
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/****************************************************************************
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seek a file. Try to avoid the seek if possible
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****************************************************************************/
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SMB_OFF_T seek_file(files_struct *fsp,SMB_OFF_T pos)
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{
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SMB_OFF_T offset = 0;
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SMB_OFF_T seek_ret;
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if (fsp->print_file && lp_postscript(fsp->conn->service))
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offset = 3;
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seek_ret = fsp->conn->vfs_ops.lseek(fsp,fsp->fd,pos+offset,SEEK_SET);
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/*
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* We want to maintain the fiction that we can seek
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* on a fifo for file system purposes. This allows
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* people to set up UNIX fifo's that feed data to Windows
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* applications. JRA.
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*/
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if((seek_ret == -1) && (errno == ESPIPE)) {
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seek_ret = pos+offset;
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errno = 0;
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}
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if((seek_ret == -1) || (seek_ret != pos+offset)) {
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DEBUG(0,("seek_file: sys_lseek failed. Error was %s\n", strerror(errno) ));
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fsp->pos = -1;
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return -1;
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}
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fsp->pos = seek_ret - offset;
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DEBUG(10,("seek_file: requested pos = %.0f, new pos = %.0f\n",
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(double)(pos+offset), (double)fsp->pos ));
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return(fsp->pos);
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}
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/****************************************************************************
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Read from write cache if we can.
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****************************************************************************/
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BOOL read_from_write_cache(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
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{
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write_cache *wcp = fsp->wcp;
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if(!wcp)
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return False;
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if(n > wcp->data_size || pos < wcp->offset || pos + n > wcp->offset + wcp->data_size)
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return False;
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memcpy(data, wcp->data + (pos - wcp->offset), n);
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DO_PROFILE_INC(writecache_read_hits);
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return True;
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}
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/****************************************************************************
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read from a file
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****************************************************************************/
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ssize_t read_file(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
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{
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ssize_t ret=0,readret;
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/* you can't read from print files */
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if (fsp->print_file)
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return -1;
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/*
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* Serve from write cache if we can.
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*/
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if(read_from_write_cache(fsp, data, pos, n))
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return n;
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flush_write_cache(fsp, READ_FLUSH);
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if (seek_file(fsp,pos) == -1) {
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DEBUG(3,("read_file: Failed to seek to %.0f\n",(double)pos));
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return(ret);
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}
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if (n > 0) {
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#ifdef DMF_FIX
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int numretries = 3;
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tryagain:
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readret = fsp->conn->vfs_ops.read(fsp,fsp->fd,data,n);
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if (readret == -1) {
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if ((errno == EAGAIN) && numretries) {
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DEBUG(3,("read_file EAGAIN retry in 10 seconds\n"));
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(void)sleep(10);
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--numretries;
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goto tryagain;
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}
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return -1;
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}
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#else /* NO DMF fix. */
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readret = fsp->conn->vfs_ops.read(fsp,fsp->fd,data,n);
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if (readret == -1)
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return -1;
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#endif
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if (readret > 0)
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ret += readret;
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}
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return(ret);
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}
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/* how many write cache buffers have been allocated */
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static unsigned int allocated_write_caches;
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/****************************************************************************
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*Really* write to a file.
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****************************************************************************/
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static ssize_t real_write_file(files_struct *fsp,char *data,SMB_OFF_T pos, size_t n)
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{
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if ((pos != -1) && (seek_file(fsp,pos) == -1))
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return -1;
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return vfs_write_data(fsp,data,n);
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}
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/****************************************************************************
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write to a file
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****************************************************************************/
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ssize_t write_file(files_struct *fsp, char *data, SMB_OFF_T pos, size_t n)
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{
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write_cache *wcp = fsp->wcp;
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ssize_t total_written = 0;
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int write_path = -1;
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if (fsp->print_file) {
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return print_job_write(fsp->print_jobid, data, n);
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}
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if (!fsp->can_write) {
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errno = EPERM;
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return(0);
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}
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if (!fsp->modified) {
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SMB_STRUCT_STAT st;
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fsp->modified = True;
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if (fsp->conn->vfs_ops.fstat(fsp,fsp->fd,&st) == 0) {
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int dosmode = dos_mode(fsp->conn,fsp->fsp_name,&st);
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if (MAP_ARCHIVE(fsp->conn) && !IS_DOS_ARCHIVE(dosmode)) {
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file_chmod(fsp->conn,fsp->fsp_name,dosmode | aARCH,&st);
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}
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/*
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* If this is the first write and we have an exclusive oplock then setup
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* the write cache.
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*/
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if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && !wcp) {
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setup_write_cache(fsp, st.st_size);
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wcp = fsp->wcp;
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}
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}
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}
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#ifdef WITH_PROFILE
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DO_PROFILE_INC(writecache_total_writes);
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if (!fsp->oplock_type) {
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DO_PROFILE_INC(writecache_non_oplock_writes);
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}
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#endif
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/*
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* If this file is level II oplocked then we need
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* to grab the shared memory lock and inform all
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* other files with a level II lock that they need
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* to flush their read caches. We keep the lock over
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* the shared memory area whilst doing this.
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*/
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release_level_2_oplocks_on_change(fsp);
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#ifdef WITH_PROFILE
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if (profile_p && profile_p->writecache_total_writes % 500 == 0) {
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DEBUG(3,("WRITECACHE: initwrites=%u abutted=%u total=%u \
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nonop=%u allocated=%u active=%u direct=%u perfect=%u readhits=%u\n",
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profile_p->writecache_init_writes,
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profile_p->writecache_abutted_writes,
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profile_p->writecache_total_writes,
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profile_p->writecache_non_oplock_writes,
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profile_p->writecache_allocated_write_caches,
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profile_p->writecache_num_write_caches,
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profile_p->writecache_direct_writes,
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profile_p->writecache_num_perfect_writes,
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profile_p->writecache_read_hits ));
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DEBUG(3,("WRITECACHE: Flushes SEEK=%d, READ=%d, WRITE=%d, READRAW=%d, OPLOCK=%d, CLOSE=%d, SYNC=%d\n",
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profile_p->writecache_flushed_writes[SEEK_FLUSH],
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profile_p->writecache_flushed_writes[READ_FLUSH],
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profile_p->writecache_flushed_writes[WRITE_FLUSH],
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profile_p->writecache_flushed_writes[READRAW_FLUSH],
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profile_p->writecache_flushed_writes[OPLOCK_RELEASE_FLUSH],
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profile_p->writecache_flushed_writes[CLOSE_FLUSH],
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profile_p->writecache_flushed_writes[SYNC_FLUSH] ));
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}
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#endif
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if(!wcp) {
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DO_PROFILE_INC(writecache_direct_writes);
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return real_write_file(fsp, data, pos, n);
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}
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DEBUG(9,("write_file(fd=%d pos=%d size=%d) wofs=%d wsize=%d\n",
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fsp->fd, (int)pos, (int)n, (int)wcp->offset, (int)wcp->data_size));
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/*
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* If we have active cache and it isn't contiguous then we flush.
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* NOTE: There is a small problem with running out of disk ....
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*/
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if (wcp->data_size) {
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BOOL cache_flush_needed = False;
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if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
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/*
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* Start of write overlaps or abutts the existing data.
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*/
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size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
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memcpy(wcp->data + (pos - wcp->offset), data, data_used);
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/*
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* Update the current buffer size with the new data.
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*/
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if(pos + data_used > wcp->offset + wcp->data_size)
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wcp->data_size = pos + data_used - wcp->offset;
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/*
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* If we used all the data then
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* return here.
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*/
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if(n == data_used)
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return n;
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else
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cache_flush_needed = True;
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/*
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* Move the start of data forward by the amount used,
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* cut down the amount left by the same amount.
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*/
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data += data_used;
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pos += data_used;
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n -= data_used;
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DO_PROFILE_INC(writecache_abutted_writes);
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total_written = data_used;
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write_path = 1;
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} else if ((pos < wcp->offset) && (pos + n > wcp->offset) &&
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(pos + n <= wcp->offset + wcp->alloc_size)) {
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/*
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* End of write overlaps the existing data.
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*/
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size_t data_used = pos + n - wcp->offset;
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memcpy(wcp->data, data + n - data_used, data_used);
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/*
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* Update the current buffer size with the new data.
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*/
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if(pos + n > wcp->offset + wcp->data_size)
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wcp->data_size = pos + n - wcp->offset;
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/*
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* We don't need to move the start of data, but we
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* cut down the amount left by the amount used.
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*/
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n -= data_used;
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/*
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* We cannot have used all the data here.
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*/
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cache_flush_needed = True;
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DO_PROFILE_INC(writecache_abutted_writes);
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total_written = data_used;
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write_path = 2;
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} else if ( (pos >= wcp->file_size) &&
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(pos > wcp->offset + wcp->data_size) &&
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(pos < wcp->offset + wcp->alloc_size) ) {
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/*
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* Non-contiguous write part of which fits within
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* the cache buffer and is extending the file.
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*/
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size_t data_used;
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if(pos + n <= wcp->offset + wcp->alloc_size)
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data_used = n;
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else
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data_used = wcp->offset + wcp->alloc_size - pos;
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/*
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* Fill in the non-continuous area with zeros.
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*/
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memset(wcp->data + wcp->data_size, '\0',
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pos - (wcp->offset + wcp->data_size) );
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memcpy(wcp->data + (pos - wcp->offset), data, data_used);
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/*
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* Update the current buffer size with the new data.
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*/
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if(pos + data_used > wcp->offset + wcp->data_size)
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wcp->data_size = pos + data_used - wcp->offset;
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/*
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* Update the known file length.
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*/
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wcp->file_size = wcp->offset + wcp->data_size;
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/*
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* If we used all the data then
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* return here.
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*/
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if(n == data_used)
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return n;
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else
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cache_flush_needed = True;
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/*
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* Move the start of data forward by the amount used,
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* cut down the amount left by the same amount.
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*/
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data += data_used;
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pos += data_used;
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n -= data_used;
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DO_PROFILE_INC(writecache_abutted_writes);
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total_written = data_used;
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write_path = 3;
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} else {
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/*
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* Write is bigger than buffer, or there is no overlap on the
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* low or high ends.
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*/
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DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
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len = %u\n",fsp->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
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/*
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* Update the file size if needed.
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*/
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if(pos + n > wcp->file_size)
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wcp->file_size = pos + n;
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/*
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* If write would fit in the cache, and is larger than
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* the data already in the cache, flush the cache and
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* preferentially copy the data new data into it. Otherwise
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* just write the data directly.
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*/
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if ( n <= wcp->alloc_size && n > wcp->data_size) {
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cache_flush_needed = True;
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} else {
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DO_PROFILE_INC(writecache_direct_writes);
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return real_write_file(fsp, data, pos, n);
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}
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write_path = 4;
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}
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if(wcp->data_size > wcp->file_size)
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wcp->file_size = wcp->data_size;
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if (cache_flush_needed) {
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DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
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n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
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write_path, fsp->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
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(double)wcp->offset, (unsigned int)wcp->data_size ));
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flush_write_cache(fsp, WRITE_FLUSH);
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}
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}
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/*
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* If the write request is bigger than the cache
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* size, write it all out.
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*/
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if (n > wcp->alloc_size ) {
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if(real_write_file(fsp, data, pos, n) == -1)
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return -1;
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DO_PROFILE_INC(writecache_direct_writes);
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return total_written + n;
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}
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/*
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* If there's any data left, cache it.
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*/
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if (n) {
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#ifdef WITH_PROFILE
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if (wcp->data_size) {
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DO_PROFILE_INC(writecache_abutted_writes);
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} else {
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DO_PROFILE_INC(writecache_init_writes);
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}
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#endif
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memcpy(wcp->data+wcp->data_size, data, n);
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if (wcp->data_size == 0) {
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wcp->offset = pos;
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DO_PROFILE_INC(writecache_num_write_caches);
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}
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wcp->data_size += n;
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DEBUG(9,("cache return %u\n", (unsigned int)n));
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total_written += n;
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return total_written; /* .... that's a write :) */
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}
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return total_written;
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}
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/****************************************************************************
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Delete the write cache structure.
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****************************************************************************/
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void delete_write_cache(files_struct *fsp)
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{
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write_cache *wcp;
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if(!fsp)
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return;
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if(!(wcp = fsp->wcp))
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return;
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DO_PROFILE_DEC(writecache_allocated_write_caches);
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allocated_write_caches--;
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SMB_ASSERT(wcp->data_size == 0);
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SAFE_FREE(wcp->data);
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SAFE_FREE(fsp->wcp);
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DEBUG(10,("delete_write_cache: File %s deleted write cache\n", fsp->fsp_name ));
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}
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/****************************************************************************
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Setup the write cache structure.
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****************************************************************************/
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static BOOL setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
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{
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ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
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write_cache *wcp;
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if (allocated_write_caches >= MAX_WRITE_CACHES)
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return False;
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if(alloc_size == 0 || fsp->wcp)
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return False;
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if((wcp = (write_cache *)malloc(sizeof(write_cache))) == NULL) {
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DEBUG(0,("setup_write_cache: malloc fail.\n"));
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return False;
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}
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wcp->file_size = file_size;
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wcp->offset = 0;
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wcp->alloc_size = alloc_size;
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wcp->data_size = 0;
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if((wcp->data = malloc(wcp->alloc_size)) == NULL) {
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DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
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(unsigned int)wcp->alloc_size ));
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SAFE_FREE(wcp);
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return False;
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}
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fsp->wcp = wcp;
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DO_PROFILE_INC(writecache_allocated_write_caches);
|
|
allocated_write_caches++;
|
|
|
|
DEBUG(10,("setup_write_cache: File %s allocated write cache size %u\n",
|
|
fsp->fsp_name, wcp->alloc_size ));
|
|
|
|
return True;
|
|
}
|
|
|
|
/****************************************************************************
|
|
Cope with a size change.
|
|
****************************************************************************/
|
|
|
|
void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
|
|
{
|
|
if(fsp->wcp) {
|
|
flush_write_cache(fsp, SIZECHANGE_FLUSH);
|
|
fsp->wcp->file_size = file_size;
|
|
}
|
|
}
|
|
|
|
/*******************************************************************
|
|
Flush a write cache struct to disk.
|
|
********************************************************************/
|
|
|
|
ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
|
|
{
|
|
write_cache *wcp = fsp->wcp;
|
|
size_t data_size;
|
|
|
|
if(!wcp || !wcp->data_size)
|
|
return 0;
|
|
|
|
data_size = wcp->data_size;
|
|
wcp->data_size = 0;
|
|
|
|
DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
|
|
|
|
DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
|
|
fsp->fd, (double)wcp->offset, (unsigned int)data_size));
|
|
|
|
#ifdef WITH_PROFILE
|
|
if(data_size == wcp->alloc_size)
|
|
DO_PROFILE_INC(writecache_num_perfect_writes);
|
|
#endif
|
|
|
|
return real_write_file(fsp, wcp->data, wcp->offset, data_size);
|
|
}
|
|
|
|
/*******************************************************************
|
|
sync a file
|
|
********************************************************************/
|
|
|
|
void sync_file(connection_struct *conn, files_struct *fsp)
|
|
{
|
|
if(lp_strict_sync(SNUM(conn)) && fsp->fd != -1) {
|
|
flush_write_cache(fsp, SYNC_FLUSH);
|
|
conn->vfs_ops.fsync(fsp,fsp->fd);
|
|
}
|
|
}
|