/* Unix SMB/Netbios implementation. 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 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" static BOOL setup_write_cache(files_struct *, SMB_OFF_T); /**************************************************************************** Read from write cache if we can. ****************************************************************************/ static BOOL read_from_write_cache(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n) { write_cache *wcp = fsp->wcp; if(!wcp) { return False; } if( n > wcp->data_size || pos < wcp->offset || pos + n > wcp->offset + wcp->data_size) { return False; } memcpy(data, wcp->data + (pos - wcp->offset), n); DO_PROFILE_INC(writecache_read_hits); return True; } /**************************************************************************** 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; /* you can't read from print files */ if (fsp->print_file) { return -1; } /* * Serve from write cache if we can. */ if(read_from_write_cache(fsp, data, pos, n)) { fsp->fh->pos = pos + n; fsp->fh->position_information = fsp->fh->pos; return n; } flush_write_cache(fsp, READ_FLUSH); fsp->fh->pos = pos; if (n > 0) { #ifdef DMF_FIX int numretries = 3; tryagain: readret = SMB_VFS_PREAD(fsp,fsp->fh->fd,data,n,pos); 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_PREAD(fsp,fsp->fh->fd,data,n,pos); if (readret == -1) { return -1; } #endif if (readret > 0) { ret += readret; } } DEBUG(10,("read_file (%s): pos = %.0f, size = %lu, returned %lu\n", fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret )); fsp->fh->pos += ret; fsp->fh->position_information = fsp->fh->pos; 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,const char *data, SMB_OFF_T pos, size_t n) { ssize_t ret; if (pos == -1) { ret = vfs_write_data(fsp, data, n); } else { fsp->fh->pos = pos; if (pos && lp_strict_allocate(SNUM(fsp->conn))) { if (vfs_fill_sparse(fsp, pos) == -1) { return -1; } } ret = vfs_pwrite_data(fsp, data, n, pos); } DEBUG(10,("real_write_file (%s): pos = %.0f, size = %lu, returned %ld\n", fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret )); if (ret != -1) { fsp->fh->pos += ret; /* * It turns out that setting the last write time from a Windows * client stops any subsequent writes from updating the write time. * Doing this after the write gives a race condition here where * a stat may see the changed write time before we reset it here, * but it's cheaper than having to store the write time in shared * memory and look it up using dev/inode across all running smbd's. * The 99% solution will hopefully be good enough in this case. JRA. */ if (!null_timespec(fsp->pending_modtime)) { set_filetime(fsp->conn, fsp->fsp_name, fsp->pending_modtime); /* If we didn't get the "set modtime" call ourselves, we must store the last write time to restore on close. JRA. */ if (!fsp->pending_modtime_owner) { fsp->last_write_time = timespec_current(); } } /* Yes - this is correct - writes don't update this. JRA. */ /* Found by Samba4 tests. */ #if 0 fsp->position_information = fsp->pos; #endif } return ret; } /**************************************************************************** File size cache change. Updates size on disk but doesn't flush the cache. ****************************************************************************/ static int wcp_file_size_change(files_struct *fsp) { int ret; write_cache *wcp = fsp->wcp; wcp->file_size = wcp->offset + wcp->data_size; ret = SMB_VFS_FTRUNCATE(fsp, fsp->fh->fd, wcp->file_size); if (ret == -1) { DEBUG(0,("wcp_file_size_change (%s): ftruncate of size %.0f error %s\n", fsp->fsp_name, (double)wcp->file_size, strerror(errno) )); } return ret; } /**************************************************************************** Write to a file. ****************************************************************************/ ssize_t write_file(files_struct *fsp, const 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) { fstring sharename; uint32 jobid; if (!rap_to_pjobid(fsp->rap_print_jobid, sharename, &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, pos, n); } if (!fsp->can_write) { errno = EPERM; return -1; } if (!fsp->modified) { SMB_STRUCT_STAT st; fsp->modified = True; if (SMB_VFS_FSTAT(fsp,fsp->fh->fd,&st) == 0) { int dosmode = dos_mode(fsp->conn,fsp->fsp_name,&st); if ((lp_store_dos_attributes(SNUM(fsp->conn)) || MAP_ARCHIVE(fsp->conn)) && !IS_DOS_ARCHIVE(dosmode)) { file_set_dosmode(fsp->conn,fsp->fsp_name,dosmode | aARCH,&st, False); } /* * 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); 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->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size)); fsp->fh->pos = pos + n; /* * 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) { if (wcp_file_size_change(fsp) == -1) { return -1; } } /* * 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) { if (wcp_file_size_change(fsp) == -1) { return -1; } } /* * 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) { if (wcp_file_size_change(fsp) == -1) { return -1; } } /* * 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 if ( (pos >= wcp->file_size) && (n == 1) && (pos < wcp->offset + 2*wcp->alloc_size) && (wcp->file_size == wcp->offset + wcp->data_size)) { /* +---------------+ | Cached data | +---------------+ +--------+ | 1 Byte | +--------+ MS-Office seems to do this a lot to determine if there's enough space on the filesystem to write a new file. */ SMB_BIG_UINT new_start = wcp->offset + wcp->data_size; flush_write_cache(fsp, WRITE_FLUSH); wcp->offset = new_start; wcp->data_size = pos - new_start + 1; memset(wcp->data, '\0', wcp->data_size); memcpy(wcp->data + wcp->data_size-1, data, 1); /* * Update the file size if changed. */ if (wcp->offset + wcp->data_size > wcp->file_size) { if (wcp_file_size_change(fsp) == -1) { return -1; } } return n; } 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->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_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->fh->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; } return ret; } write_path = 4; } 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->fh->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; } 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) { if (wcp_file_size_change(fsp) == -1) { return -1; } } 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 = SMB_MALLOC_P(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 = (char *)SMB_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 %lu\n", fsp->fsp_name, (unsigned long)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) { /* The cache *must* have been flushed before we do this. */ if (fsp->wcp->data_size != 0) { char *msg; asprintf(&msg, "set_filelen_write_cache: size change " "on file %s with write cache size = %lu\n", fsp->fsp_name, (unsigned long)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->fh->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 ********************************************************************/ NTSTATUS sync_file(connection_struct *conn, files_struct *fsp, BOOL write_through) { if (fsp->fh->fd == -1) return NT_STATUS_INVALID_HANDLE; if (lp_strict_sync(SNUM(conn)) && (lp_syncalways(SNUM(conn)) || write_through)) { int ret = flush_write_cache(fsp, SYNC_FLUSH); if (ret == -1) { return map_nt_error_from_unix(errno); } ret = SMB_VFS_FSYNC(fsp,fsp->fh->fd); if (ret == -1) { return map_nt_error_from_unix(errno); } } return NT_STATUS_OK; } /************************************************************ Perform a stat whether a valid fd or not. ************************************************************/ int fsp_stat(files_struct *fsp, SMB_STRUCT_STAT *pst) { if (fsp->fh->fd == -1) { return SMB_VFS_STAT(fsp->conn, fsp->fsp_name, pst); } else { return SMB_VFS_FSTAT(fsp,fsp->fh->fd, pst); } }