/* 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 . */ #include "includes.h" #include "printing.h" #include "smbd/smbd.h" #include "smbd/globals.h" #include "smbprofile.h" struct write_cache { off_t file_size; off_t offset; size_t alloc_size; size_t data_size; char *data; }; static bool setup_write_cache(files_struct *, off_t); /**************************************************************************** Read from write cache if we can. ****************************************************************************/ static bool read_from_write_cache(files_struct *fsp,char *data,off_t pos,size_t n) { struct 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_cached_reads); return True; } /**************************************************************************** Read from a file. ****************************************************************************/ ssize_t read_file(files_struct *fsp,char *data,off_t pos,size_t n) { ssize_t ret = 0; /* you can't read from print files */ if (fsp->print_file) { errno = EBADF; 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, SAMBA_READ_FLUSH); fsp->fh->pos = pos; if (n > 0) { ret = SMB_VFS_PREAD(fsp,data,n,pos); if (ret == -1) { return -1; } } DEBUG(10,("read_file (%s): pos = %.0f, size = %lu, returned %lu\n", fsp_str_dbg(fsp), (double)pos, (unsigned long)n, (long)ret)); fsp->fh->pos += ret; fsp->fh->position_information = fsp->fh->pos; return(ret); } /**************************************************************************** *Really* write to a file. ****************************************************************************/ static ssize_t real_write_file(struct smb_request *req, files_struct *fsp, const char *data, off_t pos, size_t n) { ssize_t ret; fsp->fh->pos = pos; if (pos && lp_strict_allocate(SNUM(fsp->conn) && !fsp->is_sparse)) { 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_str_dbg(fsp), (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; struct 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_str_dbg(fsp), (double)wcp->file_size, strerror(errno))); } return ret; } void fsp_flush_write_time_update(struct files_struct *fsp) { /* * Note this won't expect any impersonation! * So don't call any SMB_VFS operations here! */ DEBUG(5, ("Update write time on %s\n", fsp_str_dbg(fsp))); /* change the write time in the open file db. */ (void)set_write_time(fsp->file_id, timespec_current()); /* And notify. */ notify_fname(fsp->conn, NOTIFY_ACTION_MODIFIED, FILE_NOTIFY_CHANGE_LAST_WRITE, fsp->fsp_name->base_name); /* Remove the timed event handler. */ TALLOC_FREE(fsp->update_write_time_event); } static void update_write_time_handler(struct tevent_context *ctx, struct tevent_timer *te, struct timeval now, void *private_data) { files_struct *fsp = (files_struct *)private_data; fsp_flush_write_time_update(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->posix_flags & FSP_POSIX_FLAGS_OPEN) { /* Don't use delayed writes on POSIX files. */ return; } if (fsp->write_time_forced) { /* No point - "sticky" write times * in effect. */ return; } /* We need to remember someone did a write * and update to current time on close. */ fsp->update_write_time_on_close = true; if (fsp->update_write_time_triggered) { /* * We only update the write time after 2 seconds * on the first normal write. After that * no other writes affect this until close. */ return; } fsp->update_write_time_triggered = true; delay = lp_parm_int(SNUM(fsp->conn), "smbd", "writetimeupdatedelay", WRITE_TIME_UPDATE_USEC_DELAY); DEBUG(5, ("Update write time %d usec later on %s\n", delay, fsp_str_dbg(fsp))); /* trigger the update 2 seconds later */ fsp->update_write_time_event = tevent_add_timer(fsp->conn->sconn->ev_ctx, NULL, timeval_current_ofs_usec(delay), update_write_time_handler, fsp); } void trigger_write_time_update_immediate(struct files_struct *fsp) { struct smb_file_time ft; if (fsp->posix_flags & FSP_POSIX_FLAGS_OPEN) { /* Don't use delayed writes on POSIX files. */ return; } 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_str_dbg(fsp))); /* After an immediate update, reset the trigger. */ fsp->update_write_time_triggered = true; fsp->update_write_time_on_close = false; ft = (struct smb_file_time) { .mtime = timespec_current() }; /* Update the time in the open file db. */ (void)set_write_time(fsp->file_id, ft.mtime); /* Now set on disk - takes care of notify. */ (void)smb_set_file_time(fsp->conn, fsp, fsp->fsp_name, &ft, false); } void mark_file_modified(files_struct *fsp) { int dosmode; if (fsp->modified) { return; } fsp->modified = true; if (SMB_VFS_FSTAT(fsp, &fsp->fsp_name->st) != 0) { return; } trigger_write_time_update(fsp); if (fsp->posix_flags & FSP_POSIX_FLAGS_OPEN) { return; } if (!(lp_store_dos_attributes(SNUM(fsp->conn)) || MAP_ARCHIVE(fsp->conn))) { return; } dosmode = dos_mode(fsp->conn, fsp->fsp_name); if (IS_DOS_ARCHIVE(dosmode)) { return; } file_set_dosmode(fsp->conn, fsp->fsp_name, dosmode | FILE_ATTRIBUTE_ARCHIVE, NULL, false); } /**************************************************************************** Write to a file. ****************************************************************************/ ssize_t write_file(struct smb_request *req, files_struct *fsp, const char *data, off_t pos, size_t n) { struct write_cache *wcp = fsp->wcp; ssize_t total_written = 0; int write_path = -1; if (fsp->print_file) { uint32_t t; int ret; ret = print_spool_write(fsp, data, n, pos, &t); if (ret) { errno = ret; return -1; } return t; } if (!fsp->can_write) { errno = EPERM; return -1; } /* * If this is the first write and we have an exclusive oplock * then setup the write cache. */ if (!fsp->modified && EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && (wcp == NULL)) { /* * Note: no write cache with leases! * as the handles would have to share the write cache * that's possible but an improvement for another day... */ setup_write_cache(fsp, fsp->fsp_name->st.st_ex_size); wcp = fsp->wcp; } mark_file_modified(fsp); DO_PROFILE_INC(writecache_total_writes); if (!fsp->oplock_type) { DO_PROFILE_INC(writecache_non_oplock_writes); } /* * 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. */ /* This should actually be improved to span the write. */ contend_level2_oplocks_begin(fsp, LEVEL2_CONTEND_WRITE); contend_level2_oplocks_end(fsp, LEVEL2_CONTEND_WRITE); if (wcp && req->unread_bytes) { /* If we're using receivefile don't * deal with a write cache. */ flush_write_cache(fsp, SAMBA_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_str_dbg(fsp), fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size)); fsp->fh->pos = pos + n; if ((n == 1) && (data[0] == '\0') && (pos > wcp->file_size)) { int ret; /* * This is a 1-byte write of a 0 beyond the EOF and * thus implicitly also beyond the current active * write cache, the typical file-extending (and * allocating, but we're using the write cache here) * write done by Windows. We just have to ftruncate * the file and rely on posix semantics to return * zeros for non-written file data that is within the * file length. * * We can not use wcp_file_size_change here because we * might have an existing write cache, and * wcp_file_size_change assumes a change to just the * end of the current write cache. */ wcp->file_size = pos + 1; 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_str_dbg(fsp), (double)wcp->file_size, strerror(errno))); return -1; } return 1; } /* * 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; 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, SAMBA_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)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, ("SAMBA_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, SAMBA_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) { DO_PROFILE_INC(writecache_cached_writes); if (wcp->data_size) { DO_PROFILE_INC(writecache_abutted_writes); } else { DO_PROFILE_INC(writecache_init_writes); } if ((wcp->data_size == 0) && (pos > wcp->file_size) && (pos + n <= wcp->file_size + wcp->alloc_size)) { /* * This is a write completely beyond the * current EOF, but within reach of the write * cache. We expect fill-up writes pretty * soon, so it does not make sense to start * the write cache at the current * offset. These fill-up writes would trigger * separate pwrites or even unnecessary cache * flushes because they overlap if this is a * one-byte allocating write. */ wcp->offset = wcp->file_size; wcp->data_size = pos - wcp->file_size; memset(wcp->data, 0, wcp->data_size); } memcpy(wcp->data+wcp->data_size, data, n); if (wcp->data_size == 0) { wcp->offset = pos; } 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) { struct write_cache *wcp; if(!fsp) { return; } if(!(wcp = fsp->wcp)) { return; } DO_PROFILE_INC(writecache_deallocations); 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_str_dbg(fsp))); } /**************************************************************************** Setup the write cache structure. ****************************************************************************/ static bool setup_write_cache(files_struct *fsp, off_t file_size) { ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn)); struct 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(struct 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_allocations); allocated_write_caches++; DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n", fsp_str_dbg(fsp), (unsigned long)wcp->alloc_size)); return True; } /**************************************************************************** Cope with a size change. ****************************************************************************/ void set_filelen_write_cache(files_struct *fsp, 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; if (asprintf(&msg, "set_filelen_write_cache: size change " "on file %s with write cache size = %lu\n", fsp->fsp_name->base_name, (unsigned long)fsp->wcp->data_size) != -1) { smb_panic(msg); } else { smb_panic("set_filelen_write_cache"); } } 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) { struct 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; switch (reason) { case SAMBA_SEEK_FLUSH: DO_PROFILE_INC(writecache_flush_reason_seek); break; case SAMBA_READ_FLUSH: DO_PROFILE_INC(writecache_flush_reason_read); break; case SAMBA_WRITE_FLUSH: DO_PROFILE_INC(writecache_flush_reason_write);; break; case SAMBA_READRAW_FLUSH: DO_PROFILE_INC(writecache_flush_reason_readraw); break; case SAMBA_OPLOCK_RELEASE_FLUSH: DO_PROFILE_INC(writecache_flush_reason_oplock); break; case SAMBA_CLOSE_FLUSH: DO_PROFILE_INC(writecache_flush_reason_close); break; case SAMBA_SYNC_FLUSH: DO_PROFILE_INC(writecache_flush_reason_sync); break; case SAMBA_SIZECHANGE_FLUSH: DO_PROFILE_INC(writecache_flush_reason_sizechange); break; default: break; } DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n", fsp->fh->fd, (double)wcp->offset, (unsigned int)data_size)); if(data_size == wcp->alloc_size) { DO_PROFILE_INC(writecache_perfect_writes); } 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_sync_always(SNUM(conn)) || write_through)) { int ret = flush_write_cache(fsp, SAMBA_SYNC_FLUSH); if (ret == -1) { return map_nt_error_from_unix(errno); } ret = smb_vfs_fsync_sync(fsp); if (ret == -1) { return map_nt_error_from_unix(errno); } } return NT_STATUS_OK; }