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samba-mirror/source3/smbd/fileio.c

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/*
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,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,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(struct smb_request *req,
files_struct *fsp,
const char *data,
SMB_OFF_T pos,
size_t n)
{
ssize_t ret;
if (pos == -1) {
ret = vfs_write_data(req, 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(req, 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;
/* 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, 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;
}
static void update_write_time_handler(struct event_context *ctx,
struct timed_event *te,
const struct timeval *now,
void *private_data)
{
files_struct *fsp = (files_struct *)private_data;
/* Remove the timed event handler. */
TALLOC_FREE(fsp->update_write_time_event);
DEBUG(5, ("Update write time on %s\n", fsp->fsp_name));
/* change the write time if not already changed by someone else */
update_write_time(fsp);
}
/*********************************************************
Schedule a write time update for WRITE_TIME_UPDATE_USEC_DELAY
in the future.
*********************************************************/
void trigger_write_time_update(struct files_struct *fsp)
{
int delay;
if (fsp->write_time_forced) {
/* No point - "sticky" write times
* in effect.
*/
return;
}
if (fsp->update_write_time_triggered) {
/*
* We only update the write time
* on the first write. After that
* no other writes affect this.
*/
return;
}
fsp->update_write_time_triggered = true;
delay = lp_parm_int(SNUM(fsp->conn),
"smbd", "writetimeupdatedelay",
WRITE_TIME_UPDATE_USEC_DELAY);
/* trigger the update 2 seconds later */
fsp->update_write_time_on_close = true;
fsp->update_write_time_event =
event_add_timed(smbd_event_context(), NULL,
timeval_current_ofs(0, delay),
"update_write_time_handler",
update_write_time_handler, fsp);
}
void trigger_write_time_update_immediate(struct files_struct *fsp)
{
if (fsp->write_time_forced) {
/*
* No point - "sticky" write times
* in effect.
*/
return;
}
TALLOC_FREE(fsp->update_write_time_event);
DEBUG(5, ("Update write time immediate on %s\n", fsp->fsp_name));
fsp->update_write_time_triggered = true;
fsp->update_write_time_on_close = false;
update_write_time(fsp);
}
/****************************************************************************
Write to a file.
****************************************************************************/
ssize_t write_file(struct smb_request *req,
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, &st) == 0) {
int dosmode;
trigger_write_time_update(fsp);
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,
NULL,
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 && req->unread_bytes) {
/* If we're using receivefile don't
* deal with a write cache.
*/
flush_write_cache(fsp, WRITE_FLUSH);
delete_write_cache(fsp);
wcp = NULL;
}
if(!wcp) {
DO_PROFILE_INC(writecache_direct_writes);
total_written = real_write_file(req, 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) &&
(wcp->file_size == wcp->offset + wcp->data_size) &&
(pos < wcp->file_size + wcp->alloc_size)) {
/*
End of file ---->|
+---------------+---------------+
| Cached data | Cache buffer |
+---------------+---------------+
|<------- allocated size ---------------->|
+--------+
| 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.
Change to :
End of file ---->|
+-----------------------+--------+
| Zeroed Cached data | 1 Byte |
+-----------------------+--------+
*/
flush_write_cache(fsp, WRITE_FLUSH);
wcp->offset = wcp->file_size;
wcp->data_size = pos - wcp->file_size + 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(NULL,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(NULL,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(NULL, 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);
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, pst);
}
}