diff options
Diffstat (limited to 'source3/smbd/fileio.c')
| -rw-r--r-- | source3/smbd/fileio.c | 659 |
1 files changed, 659 insertions, 0 deletions
diff --git a/source3/smbd/fileio.c b/source3/smbd/fileio.c new file mode 100644 index 0000000000..addbcb0b3c --- /dev/null +++ b/source3/smbd/fileio.c @@ -0,0 +1,659 @@ +/* + Unix SMB/CIFS implementation. + read/write to a files_struct + Copyright (C) Andrew Tridgell 1992-1998 + + 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" + +static BOOL setup_write_cache(files_struct *, SMB_OFF_T); + +/**************************************************************************** +seek a file. Try to avoid the seek if possible +****************************************************************************/ + +SMB_OFF_T seek_file(files_struct *fsp,SMB_OFF_T pos) +{ + SMB_OFF_T offset = 0; + SMB_OFF_T seek_ret; + + if (fsp->print_file && lp_postscript(fsp->conn->service)) + offset = 3; + + seek_ret = fsp->conn->vfs_ops.lseek(fsp,fsp->fd,pos+offset,SEEK_SET); + + if(seek_ret == -1) { + DEBUG(0,("seek_file: sys_lseek failed. Error was %s\n", strerror(errno) )); + fsp->pos = -1; + return -1; + } + + fsp->pos = seek_ret - offset; + + DEBUG(10,("seek_file: requested pos = %.0f, new pos = %.0f\n", + (double)(pos+offset), (double)fsp->pos )); + + return(fsp->pos); +} + +/**************************************************************************** + Read from write cache if we can. +****************************************************************************/ + + +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)) + return n; + + flush_write_cache(fsp, READ_FLUSH); + + if (seek_file(fsp,pos) == -1) { + DEBUG(3,("read_file: Failed to seek to %.0f\n",(double)pos)); + return(ret); + } + + if (n > 0) { +#ifdef DMF_FIX + int numretries = 3; +tryagain: + readret = fsp->conn->vfs_ops.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 = fsp->conn->vfs_ops.read(fsp,fsp->fd,data,n); + if (readret == -1) + return -1; +#endif + if (readret > 0) + ret += readret; + } + + 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) +{ + if ((pos != -1) && (seek_file(fsp,pos) == -1)) + return -1; + + return vfs_write_data(fsp,data,n); +} + +/**************************************************************************** +write to a file +****************************************************************************/ + +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) { + return print_job_write(fsp->print_jobid, data, n); + } + + if (!fsp->can_write) { + errno = EPERM; + return(0); + } + + if (!fsp->modified) { + SMB_STRUCT_STAT st; + fsp->modified = True; + + if (fsp->conn->vfs_ops.fstat(fsp,fsp->fd,&st) == 0) { + int dosmode = dos_mode(fsp->conn,fsp->fsp_name,&st); + fsp->size = 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 > fsp->size)) + fsp->size = pos + total_written; + return total_written; + } + + DEBUG(9,("write_file(fd=%d pos=%.0f size=%u) wcp->offset=%.0f wcp->data_size=%u\n", + 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)) { + + /* + * 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) + fsp->size = wcp->file_size = wcp->offset + wcp->data_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)) { + + /* + * 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) + fsp->size = wcp->file_size = wcp->offset + wcp->data_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) ) { + + /* + * 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) + fsp->size = wcp->file_size = wcp->offset + wcp->data_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 = 3; + + } else { + + /* + * 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) + fsp->size = wcp->file_size = pos + n; + + /* + * 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); + + DO_PROFILE_INC(writecache_direct_writes); + if (ret == -1) + return ret; + + if (pos + ret > wcp->file_size) + fsp->size = wcp->file_size = pos + ret; + + return ret; + } + + write_path = 4; + + } + + if(wcp->data_size > wcp->file_size) + fsp->size = wcp->file_size = wcp->data_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) + fsp->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) + fsp->size = wcp->file_size = wcp->offset + wcp->data_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 = 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 +********************************************************************/ + +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); + } +} + +/************************************************************ + Perform a stat whether a valid fd or not. +************************************************************/ + +int fsp_stat(files_struct *fsp, SMB_STRUCT_STAT *pst) +{ + if (fsp->fd == -1) + return vfs_stat(fsp->conn, fsp->fsp_name, pst); + else + return vfs_fstat(fsp,fsp->fd, pst); +} |