Prefix VFS API macros with SMB_ for consistency and to avoid problems with VFS_ macro...
[tprouty/samba.git] / source / smbd / fileio.c
index ebc4544a7699485e71bc8e5260f4db1b676b277d..6be5f6af7d001b2200864bf32cfe6474dd5074aa 100644 (file)
@@ -3,6 +3,7 @@
    Version 1.9.
    read/write to a files_struct
    Copyright (C) Andrew Tridgell 1992-1998
+   Copyright (C) Jeremy Allison 2000-2002. - write cache.
    
    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
 
 #include "includes.h"
 
-extern int DEBUGLEVEL;
+static BOOL setup_write_cache(files_struct *, SMB_OFF_T);
 
+/****************************************************************************
+ Seek a file. Try to avoid the seek if possible.
+****************************************************************************/
+
+static SMB_OFF_T seek_file(files_struct *fsp,SMB_OFF_T pos)
+{
+       SMB_OFF_T seek_ret;
+
+       seek_ret = SMB_VFS_LSEEK(fsp,fsp->fd,pos,SEEK_SET);
+
+       if(seek_ret == -1) {
+               DEBUG(0,("seek_file: (%s) sys_lseek failed. Error was %s\n",
+                       fsp->fsp_name, strerror(errno) ));
+               fsp->pos = -1;
+               return -1;
+       }
+
+       fsp->pos = seek_ret;
+
+       DEBUG(10,("seek_file (%s): requested pos = %.0f, new pos = %.0f\n",
+               fsp->fsp_name, (double)pos, (double)fsp->pos ));
+
+       return(fsp->pos);
+}
 
 /****************************************************************************
-seek a file. Try to avoid the seek if possible
+ Read from write cache if we can.
 ****************************************************************************/
 
-SMB_OFF_T seek_file(files_struct *fsp,SMB_OFF_T pos)
+
+static BOOL read_from_write_cache(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
 {
-  SMB_OFF_T offset = 0;
+       write_cache *wcp = fsp->wcp;
+
+       if(!wcp)
+               return False;
 
-  if (fsp->print_file && lp_postscript(fsp->conn->service))
-    offset = 3;
+       if(n > wcp->data_size || pos < wcp->offset || pos + n > wcp->offset + wcp->data_size)
+               return False;
 
-  fsp->pos = (sys_lseek(fsp->fd_ptr->fd,pos+offset,SEEK_SET) - offset);
+       memcpy(data, wcp->data + (pos - wcp->offset), n);
 
-  DEBUG(10,("seek_file: requested pos = %.0f, new pos = %.0f\n",
-        (double)(pos+offset), (double)fsp->pos ));
+       DO_PROFILE_INC(writecache_read_hits);
 
-  return(fsp->pos);
+       return True;
 }
 
 /****************************************************************************
-read from a file
+ Read from a file.
 ****************************************************************************/
 
 ssize_t read_file(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
 {
-  ssize_t ret=0,readret;
+       ssize_t ret=0,readret;
 
-#if USE_READ_PREDICTION
-  if (!fsp->can_write) {
-    ret = read_predict(fsp->fd_ptr->fd,pos,data,NULL,n);
+       /* you can't read from print files */
+       if (fsp->print_file)
+               return -1;
 
-    data += ret;
-    n -= ret;
-    pos += ret;
-  }
-#endif
+       /*
+        * Serve from write cache if we can.
+        */
 
-#if WITH_MMAP
-  if (fsp->mmap_ptr) {
-         SMB_OFF_T num = (fsp->mmap_size > pos) ? (fsp->mmap_size - pos) : 0;
-         num = MIN(n,num);
-         if (num > 0) {
-                 memcpy(data,fsp->mmap_ptr+pos,num);
-                 data += num;
-                 pos += num;
-                 n -= num;
-                 ret += num;
-         }
-  }
-#endif
+       if(read_from_write_cache(fsp, data, pos, n))
+               return n;
+
+       flush_write_cache(fsp, READ_FLUSH);
 
-  if (seek_file(fsp,pos) != pos) {
-    DEBUG(3,("read_file: Failed to seek to %.0f\n",(double)pos));
-    return(ret);
-  }
+       if (seek_file(fsp,pos) == -1) {
+               DEBUG(3,("read_file: Failed to seek to %.0f\n",(double)pos));
+               return(ret);
+       }
   
-  if (n > 0) {
-    readret = read(fsp->fd_ptr->fd,data,n);
-    if (readret > 0) ret += readret;
-  }
+       if (n > 0) {
+#ifdef DMF_FIX
+               int numretries = 3;
+tryagain:
+               readret = SMB_VFS_READ(fsp,fsp->fd,data,n);
+               if (readret == -1) {
+                       if ((errno == EAGAIN) && numretries) {
+                               DEBUG(3,("read_file EAGAIN retry in 10 seconds\n"));
+                               (void)sleep(10);
+                               --numretries;
+                               goto tryagain;
+                       }
+                       return -1;
+               }
+#else /* NO DMF fix. */
+               readret = SMB_VFS_READ(fsp,fsp->fd,data,n);
+               if (readret == -1)
+                       return -1;
+#endif
+               if (readret > 0)
+                       ret += readret;
+       }
 
-  return(ret);
+       DEBUG(10,("read_file (%s): pos = %.0f, size = %lu, returned %lu\n",
+               fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
+
+       return(ret);
 }
 
+/* how many write cache buffers have been allocated */
+static unsigned int allocated_write_caches;
+
+/****************************************************************************
+ *Really* write to a file.
+****************************************************************************/
+
+static ssize_t real_write_file(files_struct *fsp,char *data,SMB_OFF_T pos, size_t n)
+{
+       ssize_t ret;
+
+       if ((pos != -1) && (seek_file(fsp,pos) == -1))
+               return -1;
+
+       ret = vfs_write_data(fsp,data,n);
+
+       DEBUG(10,("real_write_file (%s): pos = %.0f, size = %lu, returned %ld\n",
+               fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
+
+       return ret;
+}
 
 /****************************************************************************
 write to a file
 ****************************************************************************/
 
-ssize_t write_file(files_struct *fsp,char *data,size_t n)
+ssize_t write_file(files_struct *fsp, char *data, SMB_OFF_T pos, size_t n)
 {
+       write_cache *wcp = fsp->wcp;
+       ssize_t total_written = 0;
+       int write_path = -1; 
+
+       if (fsp->print_file) {
+               int snum;
+               uint32 jobid;
+
+               if (!rap_to_pjobid(fsp->rap_print_jobid, &snum, &jobid)) {
+                       DEBUG(3,("write_file: Unable to map RAP jobid %u to jobid.\n",
+                                               (unsigned int)fsp->rap_print_jobid ));
+                       errno = EBADF;
+                       return -1;
+               }
+
+               return print_job_write(SNUM(fsp->conn), jobid, data, n);
+       }
+
+       if (!fsp->can_write) {
+               errno = EPERM;
+               return(0);
+       }
+
+       if (!fsp->modified) {
+               SMB_STRUCT_STAT st;
+               fsp->modified = True;
+
+               if (SMB_VFS_FSTAT(fsp,fsp->fd,&st) == 0) {
+                       int dosmode = dos_mode(fsp->conn,fsp->fsp_name,&st);
+                       fsp->size = (SMB_BIG_UINT)st.st_size;
+                       if (MAP_ARCHIVE(fsp->conn) && !IS_DOS_ARCHIVE(dosmode))
+                               file_chmod(fsp->conn,fsp->fsp_name,dosmode | aARCH,&st);
+
+                       /*
+                        * If this is the first write and we have an exclusive oplock then setup
+                        * the write cache.
+                        */
+
+                       if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && !wcp) {
+                               setup_write_cache(fsp, st.st_size);
+                               wcp = fsp->wcp;
+                       } 
+               }  
+       }
+
+#ifdef WITH_PROFILE
+       DO_PROFILE_INC(writecache_total_writes);
+       if (!fsp->oplock_type) {
+               DO_PROFILE_INC(writecache_non_oplock_writes);
+       }
+#endif
+
+       /*
+        * If this file is level II oplocked then we need
+        * to grab the shared memory lock and inform all
+        * other files with a level II lock that they need
+        * to flush their read caches. We keep the lock over
+        * the shared memory area whilst doing this.
+        */
+
+       release_level_2_oplocks_on_change(fsp);
+
+#ifdef WITH_PROFILE
+       if (profile_p && profile_p->writecache_total_writes % 500 == 0) {
+               DEBUG(3,("WRITECACHE: initwrites=%u abutted=%u total=%u \
+nonop=%u allocated=%u active=%u direct=%u perfect=%u readhits=%u\n",
+                       profile_p->writecache_init_writes,
+                       profile_p->writecache_abutted_writes,
+                       profile_p->writecache_total_writes,
+                       profile_p->writecache_non_oplock_writes,
+                       profile_p->writecache_allocated_write_caches,
+                       profile_p->writecache_num_write_caches,
+                       profile_p->writecache_direct_writes,
+                       profile_p->writecache_num_perfect_writes,
+                       profile_p->writecache_read_hits ));
+
+               DEBUG(3,("WRITECACHE: Flushes SEEK=%d, READ=%d, WRITE=%d, READRAW=%d, OPLOCK=%d, CLOSE=%d, SYNC=%d\n",
+                       profile_p->writecache_flushed_writes[SEEK_FLUSH],
+                       profile_p->writecache_flushed_writes[READ_FLUSH],
+                       profile_p->writecache_flushed_writes[WRITE_FLUSH],
+                       profile_p->writecache_flushed_writes[READRAW_FLUSH],
+                       profile_p->writecache_flushed_writes[OPLOCK_RELEASE_FLUSH],
+                       profile_p->writecache_flushed_writes[CLOSE_FLUSH],
+                       profile_p->writecache_flushed_writes[SYNC_FLUSH] ));
+       }
+#endif
+
+       if(!wcp) {
+               DO_PROFILE_INC(writecache_direct_writes);
+               total_written = real_write_file(fsp, data, pos, n);
+               if ((total_written != -1) && (pos + total_written > (SMB_OFF_T)fsp->size))
+                       fsp->size = (SMB_BIG_UINT)(pos + total_written);
+               return total_written;
+       }
+
+       DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f wcp->data_size=%u\n",
+               fsp->fsp_name, fsp->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size));
+
+       /* 
+        * If we have active cache and it isn't contiguous then we flush.
+        * NOTE: There is a small problem with running out of disk ....
+        */
+
+       if (wcp->data_size) {
+
+               BOOL cache_flush_needed = False;
+
+               if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
+      
+                       /* ASCII art.... JRA.
+
+      +--------------+-----
+      | Cached data  | Rest of allocated cache buffer....
+      +--------------+-----
+
+            +-------------------+
+            | Data to write     |
+            +-------------------+
+
+                       */
+
+                       /*
+                        * Start of write overlaps or abutts the existing data.
+                        */
+
+                       size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
+
+                       memcpy(wcp->data + (pos - wcp->offset), data, data_used);
+
+                       /*
+                        * Update the current buffer size with the new data.
+                        */
+
+                       if(pos + data_used > wcp->offset + wcp->data_size)
+                               wcp->data_size = pos + data_used - wcp->offset;
+
+                       /*
+                        * Update the file size if changed.
+                        */
+
+                       if (wcp->offset + wcp->data_size > wcp->file_size) {
+                               wcp->file_size = wcp->offset + wcp->data_size;
+                               fsp->size = (SMB_BIG_UINT)wcp->file_size;
+                       }
+
+                       /*
+                        * If we used all the data then
+                        * return here.
+                        */
+
+                       if(n == data_used)
+                               return n;
+                       else
+                               cache_flush_needed = True;
+
+                       /*
+                        * Move the start of data forward by the amount used,
+                        * cut down the amount left by the same amount.
+                        */
+
+                       data += data_used;
+                       pos += data_used;
+                       n -= data_used;
+
+                       DO_PROFILE_INC(writecache_abutted_writes);
+                       total_written = data_used;
+
+                       write_path = 1;
+
+               } else if ((pos < wcp->offset) && (pos + n > wcp->offset) && 
+                                       (pos + n <= wcp->offset + wcp->alloc_size)) {
+
+                       /* ASCII art.... JRA.
+
+                        +---------------+
+                        | Cache buffer  |
+                        +---------------+
+
+            +-------------------+
+            | Data to write     |
+            +-------------------+
+
+                       */
+
+                       /*
+                        * End of write overlaps the existing data.
+                        */
+
+                       size_t data_used = pos + n - wcp->offset;
+
+                       memcpy(wcp->data, data + n - data_used, data_used);
+
+                       /*
+                        * Update the current buffer size with the new data.
+                        */
+
+                       if(pos + n > wcp->offset + wcp->data_size)
+                               wcp->data_size = pos + n - wcp->offset;
+
+                       /*
+                        * Update the file size if changed.
+                        */
+
+                       if (wcp->offset + wcp->data_size > wcp->file_size) {
+                               wcp->file_size = wcp->offset + wcp->data_size;
+                               fsp->size = (SMB_BIG_UINT)wcp->file_size;
+                       }
+
+                       /*
+                        * We don't need to move the start of data, but we
+                        * cut down the amount left by the amount used.
+                        */
+
+                       n -= data_used;
+
+                       /*
+                        * We cannot have used all the data here.
+                        */
+
+                       cache_flush_needed = True;
+
+                       DO_PROFILE_INC(writecache_abutted_writes);
+                       total_written = data_used;
+
+                       write_path = 2;
+
+               } else if ( (pos >= wcp->file_size) && 
+                                       (wcp->offset + wcp->data_size == wcp->file_size) &&
+                                       (pos > wcp->offset + wcp->data_size) && 
+                                       (pos < wcp->offset + wcp->alloc_size) ) {
+
+                       /* ASCII art.... JRA.
+
+                       End of file ---->|
+
+                        +---------------+---------------+
+                        | Cached data   | Cache buffer  |
+                        +---------------+---------------+
+
+                                              +-------------------+
+                                              | Data to write     |
+                                              +-------------------+
+
+                       */
+
+                       /*
+                        * Non-contiguous write part of which fits within
+                        * the cache buffer and is extending the file
+                        * and the cache contents reflect the current
+                        * data up to the current end of the file.
+                        */
+
+                       size_t data_used;
+
+                       if(pos + n <= wcp->offset + wcp->alloc_size)
+                               data_used = n;
+                       else
+                               data_used = wcp->offset + wcp->alloc_size - pos;
+
+                       /*
+                        * Fill in the non-continuous area with zeros.
+                        */
+
+                       memset(wcp->data + wcp->data_size, '\0',
+                               pos - (wcp->offset + wcp->data_size) );
+
+                       memcpy(wcp->data + (pos - wcp->offset), data, data_used);
+
+                       /*
+                        * Update the current buffer size with the new data.
+                        */
+
+                       if(pos + data_used > wcp->offset + wcp->data_size)
+                               wcp->data_size = pos + data_used - wcp->offset;
+
+                       /*
+                        * Update the file size if changed.
+                        */
+
+                       if (wcp->offset + wcp->data_size > wcp->file_size) {
+                               wcp->file_size = wcp->offset + wcp->data_size;
+                               fsp->size = (SMB_BIG_UINT)wcp->file_size;
+                       }
 
-  if (!fsp->can_write) {
-    errno = EPERM;
-    return(0);
-  }
-
-  if (!fsp->modified) {
-    SMB_STRUCT_STAT st;
-    fsp->modified = True;
-    if (sys_fstat(fsp->fd_ptr->fd,&st) == 0) {
-      int dosmode = dos_mode(fsp->conn,fsp->fsp_name,&st);
-      if (MAP_ARCHIVE(fsp->conn) && !IS_DOS_ARCHIVE(dosmode)) {        
-        file_chmod(fsp->conn,fsp->fsp_name,dosmode | aARCH,&st);
-      }
-    }  
-  }
-
-  return(write_data(fsp->fd_ptr->fd,data,n));
+                       /*
+                        * If we used all the data then
+                        * return here.
+                        */
+
+                       if(n == data_used)
+                               return n;
+                       else
+                               cache_flush_needed = True;
+
+                       /*
+                        * Move the start of data forward by the amount used,
+                        * cut down the amount left by the same amount.
+                        */
+
+                       data += data_used;
+                       pos += data_used;
+                       n -= data_used;
+
+                       DO_PROFILE_INC(writecache_abutted_writes);
+                       total_written = data_used;
+
+                       write_path = 3;
+
+               } else {
+
+                       /* ASCII art..... JRA.
+
+   Case 1).
+
+                        +---------------+---------------+
+                        | Cached data   | Cache buffer  |
+                        +---------------+---------------+
+
+                                                              +-------------------+
+                                                              | Data to write     |
+                                                              +-------------------+
+
+   Case 2).
+
+                           +---------------+---------------+
+                           | Cached data   | Cache buffer  |
+                           +---------------+---------------+
+
+   +-------------------+
+   | Data to write     |
+   +-------------------+
+
+    Case 3).
+
+                           +---------------+---------------+
+                           | Cached data   | Cache buffer  |
+                           +---------------+---------------+
+
+                  +-----------------------------------------------------+
+                  | Data to write                                       |
+                  +-----------------------------------------------------+
+
+                 */
+
+                       /*
+                        * Write is bigger than buffer, or there is no overlap on the
+                        * low or high ends.
+                        */
+
+                       DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
+len = %u\n",fsp->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
+
+                       /*
+                        * Update the file size if needed.
+                        */
+
+                       if(pos + n > wcp->file_size) {
+                               wcp->file_size = pos + n;
+                               fsp->size = (SMB_BIG_UINT)wcp->file_size;
+                       }
+
+                       /*
+                        * If write would fit in the cache, and is larger than
+                        * the data already in the cache, flush the cache and
+                        * preferentially copy the data new data into it. Otherwise
+                        * just write the data directly.
+                        */
+
+                       if ( n <= wcp->alloc_size && n > wcp->data_size) {
+                               cache_flush_needed = True;
+                       } else {
+                               ssize_t ret = real_write_file(fsp, data, pos, n);
+
+                               /*
+                                * If the write overlaps the entire cache, then
+                                * discard the current contents of the cache.
+                                * Fix from Rasmus Borup Hansen rbh@math.ku.dk.
+                                */
+
+                               if ((pos <= wcp->offset) &&
+                                               (pos + n >= wcp->offset + wcp->data_size) ) {
+                                       DEBUG(9,("write_file: discarding overwritten write \
+cache: fd = %d, off=%.0f, size=%u\n", fsp->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
+                                       wcp->data_size = 0;
+                               }
+
+                               DO_PROFILE_INC(writecache_direct_writes);
+                               if (ret == -1)
+                                       return ret;
+
+                               if (pos + ret > wcp->file_size) {
+                                       wcp->file_size = pos + ret;
+                                       fsp->size = (SMB_BIG_UINT)wcp->file_size;
+                               }
+
+                               return ret;
+                       }
+
+                       write_path = 4;
+
+               }
+
+               if(wcp->data_size > wcp->file_size) {
+                       wcp->file_size = wcp->data_size;
+                       fsp->size = (SMB_BIG_UINT)wcp->file_size;
+               }
+
+               if (cache_flush_needed) {
+                       DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
+n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
+                               write_path, fsp->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
+                               (double)wcp->offset, (unsigned int)wcp->data_size ));
+
+                       flush_write_cache(fsp, WRITE_FLUSH);
+               }
+       }
+
+       /*
+        * If the write request is bigger than the cache
+        * size, write it all out.
+        */
+
+       if (n > wcp->alloc_size ) {
+               ssize_t ret = real_write_file(fsp, data, pos, n);
+               if (ret == -1)
+                       return -1;
+
+               if (pos + ret > wcp->file_size) {
+                       wcp->file_size = pos + n;
+                       fsp->size = (SMB_BIG_UINT)wcp->file_size;
+               }
+
+               DO_PROFILE_INC(writecache_direct_writes);
+               return total_written + n;
+       }
+
+       /*
+        * If there's any data left, cache it.
+        */
+
+       if (n) {
+#ifdef WITH_PROFILE
+               if (wcp->data_size) {
+                       DO_PROFILE_INC(writecache_abutted_writes);
+               } else {
+                       DO_PROFILE_INC(writecache_init_writes);
+               }
+#endif
+               memcpy(wcp->data+wcp->data_size, data, n);
+               if (wcp->data_size == 0) {
+                       wcp->offset = pos;
+                       DO_PROFILE_INC(writecache_num_write_caches);
+               }
+               wcp->data_size += n;
+
+               /*
+                * Update the file size if changed.
+                */
+
+               if (wcp->offset + wcp->data_size > wcp->file_size) {
+                       wcp->file_size = wcp->offset + wcp->data_size;
+                       fsp->size = (SMB_BIG_UINT)wcp->file_size;
+               }
+               DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
+                       (double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
+
+               total_written += n;
+               return total_written; /* .... that's a write :) */
+       }
+  
+       return total_written;
 }
 
+/****************************************************************************
+ Delete the write cache structure.
+****************************************************************************/
+
+void delete_write_cache(files_struct *fsp)
+{
+       write_cache *wcp;
+
+       if(!fsp)
+               return;
+
+       if(!(wcp = fsp->wcp))
+               return;
+
+       DO_PROFILE_DEC(writecache_allocated_write_caches);
+       allocated_write_caches--;
+
+       SMB_ASSERT(wcp->data_size == 0);
+
+       SAFE_FREE(wcp->data);
+       SAFE_FREE(fsp->wcp);
+
+       DEBUG(10,("delete_write_cache: File %s deleted write cache\n", fsp->fsp_name ));
+}
+
+/****************************************************************************
+ Setup the write cache structure.
+****************************************************************************/
+
+static BOOL setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
+{
+       ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
+       write_cache *wcp;
+
+       if (allocated_write_caches >= MAX_WRITE_CACHES) 
+               return False;
+
+       if(alloc_size == 0 || fsp->wcp)
+               return False;
+
+       if((wcp = (write_cache *)malloc(sizeof(write_cache))) == NULL) {
+               DEBUG(0,("setup_write_cache: malloc fail.\n"));
+               return False;
+       }
+
+       wcp->file_size = file_size;
+       wcp->offset = 0;
+       wcp->alloc_size = alloc_size;
+       wcp->data_size = 0;
+       if((wcp->data = malloc(wcp->alloc_size)) == NULL) {
+               DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
+                       (unsigned int)wcp->alloc_size ));
+               SAFE_FREE(wcp);
+               return False;
+       }
+
+       memset(wcp->data, '\0', wcp->alloc_size );
+
+       fsp->wcp = wcp;
+       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)
+{
+       fsp->size = (SMB_BIG_UINT)file_size;
+       if(fsp->wcp) {
+               /* The cache *must* have been flushed before we do this. */
+               if (fsp->wcp->data_size != 0) {
+                       pstring msg;
+                       slprintf(msg, sizeof(msg)-1, "set_filelen_write_cache: size change \
+on file %s with write cache size = %u\n", fsp->fsp_name, fsp->wcp->data_size );
+                       smb_panic(msg);
+               }
+               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;
+       ssize_t ret;
+
+       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
+
+       ret = real_write_file(fsp, wcp->data, wcp->offset, data_size);
+
+       /*
+        * Ensure file size if kept up to date if write extends file.
+        */
+
+       if ((ret != -1) && (wcp->offset + ret > wcp->file_size))
+               wcp->file_size = wcp->offset + ret;
+
+       return ret;
+}
 
 /*******************************************************************
 sync a file
@@ -122,8 +758,21 @@ sync a file
 
 void sync_file(connection_struct *conn, files_struct *fsp)
 {
-#ifdef HAVE_FSYNC
-    if(lp_strict_sync(SNUM(conn)))
-      fsync(fsp->fd_ptr->fd);
-#endif
+       if(lp_strict_sync(SNUM(conn)) && fsp->fd != -1) {
+               flush_write_cache(fsp, SYNC_FLUSH);
+               SMB_VFS_FSYNC(fsp,fsp->fd);
+       }
+}
+
+
+/************************************************************
+ Perform a stat whether a valid fd or not.
+************************************************************/
+
+int fsp_stat(files_struct *fsp, SMB_STRUCT_STAT *pst)
+{
+       if (fsp->fd == -1)
+               return SMB_VFS_STAT(fsp->conn, fsp->fsp_name, pst);
+       else
+               return SMB_VFS_FSTAT(fsp,fsp->fd, pst);
 }