* Added a new flag for write stat: B_STAT_SIZE_INSECURE that allows a

file system to not fill newly created space with zeros. 
  BFile::SetSize() now uses this, while [f]truncate() does not. This
  is only a temporary work-around until BFS supports sparse files.
* Apps that want to reserve space to fill up later should use 
  BFile::SetSize() for now, as this will be a lot faster than 
  [f]truncate().
* cache_io() and the functions below now use a special mode when you 
  pass in a NULL buffer: for read access, the cache is only populated
  (useful for prefetching), for write access, the file is filled with
  zeros.
* Implemented BFS's Inode::FillGapWithZeros() using this method now.
* Removed extraneous white space.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@24555 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/os/drivers/fs_interface.h

@@ -27,8 +27,10 @@ typedef void *fs_cookie;
 typedef void *fs_vnode;
 
 /* additional flags passed to write_stat() (see NodeMonitor.h for the others) */
-	// NOTE: Changing the constants here or in NodeMonitor.h will break
+// NOTE: Changing the constants here or in NodeMonitor.h will break
-	// src/kits/storage/LibBeAdapter.cpp:_kern_write_stat().
+// src/kits/storage/LibBeAdapter.cpp:_kern_write_stat().
+#define B_STAT_SIZE_INSECURE	0x2000
+	// TODO: this should be faded out once BFS supports sparse files
 
 /* passed to write_fs_info() */
 #define	FS_WRITE_FSINFO_NAME	0x0001

headers/private/fs_shell/fssh_api_wrapper.h

@@ -874,6 +874,9 @@
 #define fs_cookie	fssh_fs_cookie
 #define fs_vnode	fssh_fs_vnode
 
+/* additional flags passed to write_stat() */
+#define B_STAT_SIZE_INSECURE	FSSH_B_STAT_SIZE_INSECURE
+
 /* passed to write_fs_info() */
 #define FS_WRITE_FSINFO_NAME	FSSH_FS_WRITE_FSINFO_NAME
 

headers/private/fs_shell/fssh_fs_interface.h

@@ -29,6 +29,7 @@ typedef void *fssh_fs_cookie;
 typedef void *fssh_fs_vnode;
 
 /* additional flags passed to write_stat() */
+#define FSSH_B_STAT_SIZE_INSECURE	0x2000
 
 /* passed to write_fs_info() */
 #define	FSSH_FS_WRITE_FSINFO_NAME	0x0001

src/add-ons/kernel/file_systems/bfs/Inode.cpp

@@ -407,7 +407,7 @@ Inode::InitCheck(bool checkNode)
 	}
 
 	if (IsContainer()) {
-		// inodes that have a 
+		// inodes that have a B+tree
 		if (fTree == NULL)
 			RETURN_ERROR(B_NO_MEMORY);
 
@@ -1426,8 +1426,6 @@ Inode::WriteAt(Transaction &transaction, off_t pos, const uint8 *buffer,
 	locker.Lock();
 
 	if (pos + length > Size()) {
-		off_t oldSize = Size();
-
 		// let's grow the data stream to the size needed
 		status_t status = SetFileSize(transaction, pos + length);
 		if (status < B_OK) {
@@ -1438,11 +1436,6 @@ Inode::WriteAt(Transaction &transaction, off_t pos, const uint8 *buffer,
 		// index here as part of the current transaction - this might just
 		// be a bit too expensive, but worth a try.
 
-		// If the position of the write was beyond the file size, we
-		// have to fill the gap between that position and the old file
-		// size with zeros.
-		FillGapWithZeros(oldSize, pos);
-
 		// we need to write back the inode here because it has to
 		// go into this transaction (we cannot wait until the file
 		// is closed)
@@ -1472,81 +1465,21 @@ Inode::WriteAt(Transaction &transaction, off_t pos, const uint8 *buffer,
 status_t
 Inode::FillGapWithZeros(off_t pos, off_t newSize)
 {
-	// ToDo: we currently do anything here, same as original BFS!
+	while (pos < newSize) {
-	//if (pos >= newSize)
+		size_t size;
-	return B_OK;
+		if (newSize > pos + 1024 * 1024 * 1024)
-#if 0
+			size = 1024 * 1024 * 1024;
-	block_run run;
+		else
-	off_t offset;
+			size = newSize - pos;
-	if (FindBlockRun(pos, run, offset) < B_OK)
-		RETURN_ERROR(B_BAD_VALUE);
 
-	off_t length = newSize - pos;
+		status_t status = file_cache_write(FileCache(), NULL, pos, NULL, &size);
-	uint32 bytesWritten = 0;
+		if (status < B_OK)
-	uint32 blockSize = fVolume->BlockSize();
+			return status;
-	uint32 blockShift = fVolume->BlockShift();
-	uint8 *block;
 
-	// the first block_run we write could not be aligned to the block_size boundary
+		pos += size;
-	// (write partial block at the beginning)
-
-	// pos % block_size == (pos - offset) % block_size, offset % block_size == 0
-	if (pos % blockSize != 0) {
-		run.start += (pos - offset) / blockSize;
-		run.length -= (pos - offset) / blockSize;
-
-		CachedBlock cached(fVolume,run);
-		if ((block = cached.Block()) == NULL)
-			RETURN_ERROR(B_BAD_VALUE);
-
-		bytesWritten = blockSize - (pos % blockSize);
-		if (length < bytesWritten)
-			bytesWritten = length;
-
-		memset(block + (pos % blockSize), 0, bytesWritten);
-		if (fVolume->WriteBlocks(cached.BlockNumber(), block, 1) < B_OK)
-			RETURN_ERROR(B_IO_ERROR);
-
-		pos += bytesWritten;
-
-		length -= bytesWritten;
-		if (length == 0)
-			return B_OK;
-
-		if (FindBlockRun(pos, run, offset) < B_OK)
-			RETURN_ERROR(B_BAD_VALUE);
 	}
 
-	while (length > 0) {
-		// offset is the offset to the current pos in the block_run
-		run.start = HOST_ENDIAN_TO_BFS_INT16(run.Start() + ((pos - offset) >> blockShift));
-		run.length = HOST_ENDIAN_TO_BFS_INT16(run.Length() - ((pos - offset) >> blockShift));
-
-		CachedBlock cached(fVolume);
-		off_t blockNumber = fVolume->ToBlock(run);
-		for (int32 i = 0; i < run.Length(); i++) {
-			if ((block = cached.SetTo(blockNumber + i, true)) == NULL)
-				RETURN_ERROR(B_IO_ERROR);
-
-			if (fVolume->WriteBlocks(cached.BlockNumber(), block, 1) < B_OK)
-				RETURN_ERROR(B_IO_ERROR);
-		}
-
-		int32 bytes = run.Length() << blockShift;
-		length -= bytes;
-		bytesWritten += bytes;
-
-		// since we don't respect a last partial block, length can be lower
-		if (length <= 0)
-			break;
-
-		pos += bytes;
-
-		if (FindBlockRun(pos, run, offset) < B_OK)
-			RETURN_ERROR(B_BAD_VALUE);
-	}
 	return B_OK;
-#endif
 }
 
 

src/add-ons/kernel/file_systems/bfs/kernel_interface.cpp

@@ -734,6 +734,7 @@ bfs_write_stat(void *_ns, void *_node, const struct stat *stat, uint32 mask)
 				return status;
 
 			// fill the new blocks (if any) with zeros
+			if ((mask & B_STAT_SIZE_INSECURE) == 0)
 				inode->FillGapWithZeros(inode->OldSize(), inode->Size());
 
 			if (!inode->IsDeleted()) {

src/kits/storage/File.cpp

@@ -14,6 +14,7 @@
 #include <Directory.h>
 #include <Entry.h>
 #include <File.h>
+#include <fs_interface.h>
 #include <NodeMonitor.h>
 
 #include <syscalls.h>
@@ -453,7 +454,7 @@ BFile::SetSize(off_t size)
 		return B_BAD_VALUE;
 	struct stat statData;
 	statData.st_size = size;
-	return set_stat(statData, B_STAT_SIZE);
+	return set_stat(statData, B_STAT_SIZE | B_STAT_SIZE_INSECURE);
 }
 
 

src/system/kernel/cache/file_cache.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright 2004-2007, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
+ * Copyright 2004-2008, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
  * Distributed under the terms of the MIT License.
  */
 
@@ -51,7 +51,7 @@ struct file_cache_ref {
 };
 
 typedef status_t (*cache_func)(file_cache_ref *ref, void *cookie, off_t offset,
-	int32 pageOffset, addr_t buffer, size_t bufferSize,
+	int32 pageOffset, addr_t buffer, size_t bufferSize, bool useBuffer,
 	size_t lastReservedPages, size_t reservePages);
 
 
@@ -169,7 +169,7 @@ reserve_pages(file_cache_ref *ref, size_t reservePages, bool isWrite)
 */
 static status_t
 read_into_cache(file_cache_ref *ref, void *cookie, off_t offset,
-	int32 pageOffset, addr_t buffer, size_t bufferSize,
+	int32 pageOffset, addr_t buffer, size_t bufferSize, bool useBuffer,
 	size_t lastReservedPages, size_t reservePages)
 {
 	TRACE(("read_into_cache(offset = %Ld, pageOffset = %ld, buffer = %#lx, "
@@ -240,14 +240,14 @@ read_into_cache(file_cache_ref *ref, void *cookie, off_t offset,
 		return status;
 	}
 
-	// copy the pages and unmap them again
+	// copy the pages if needed and unmap them again
 
 	for (int32 i = 0; i < vecCount; i++) {
 		addr_t base = (addr_t)vecs[i].iov_base;
 		size_t size = vecs[i].iov_len;
 
 		// copy to user buffer if necessary
-		if (bufferSize != 0) {
+		if (useBuffer && bufferSize != 0) {
 			size_t bytes = min_c(bufferSize, size - pageOffset);
 
 			user_memcpy((void *)buffer, (void *)(base + pageOffset), bytes);
@@ -278,12 +278,15 @@ read_into_cache(file_cache_ref *ref, void *cookie, off_t offset,
 
 static status_t
 read_from_file(file_cache_ref *ref, void *cookie, off_t offset,
-	int32 pageOffset, addr_t buffer, size_t bufferSize,
+	int32 pageOffset, addr_t buffer, size_t bufferSize, bool useBuffer,
 	size_t lastReservedPages, size_t reservePages)
 {
 	TRACE(("read_from_file(offset = %Ld, pageOffset = %ld, buffer = %#lx, "
 		"bufferSize = %lu\n", offset, pageOffset, buffer, bufferSize));
 
+	if (!useBuffer)
+		return B_OK;
+
 	iovec vec;
 	vec.iov_base = (void *)buffer;
 	vec.iov_len = bufferSize;
@@ -310,7 +313,7 @@ read_from_file(file_cache_ref *ref, void *cookie, off_t offset,
 */
 static status_t
 write_to_cache(file_cache_ref *ref, void *cookie, off_t offset,
-	int32 pageOffset, addr_t buffer, size_t bufferSize,
+	int32 pageOffset, addr_t buffer, size_t bufferSize, bool useBuffer,
 	size_t lastReservedPages, size_t reservePages)
 {
 	// TODO: We're using way too much stack! Rather allocate a sufficiently
@@ -400,8 +403,13 @@ write_to_cache(file_cache_ref *ref, void *cookie, off_t offset,
 		addr_t base = (addr_t)vecs[i].iov_base;
 		size_t bytes = min_c(bufferSize, size_t(vecs[i].iov_len - pageOffset));
 
+		if (useBuffer) {
 			// copy data from user buffer
 			user_memcpy((void *)(base + pageOffset), (void *)buffer, bytes);
+		} else {
+			// clear buffer instead
+			memset((void *)(base + pageOffset), 0, bytes);
+		}
 
 		bufferSize -= bytes;
 		if (bufferSize == 0)
@@ -454,9 +462,21 @@ write_to_cache(file_cache_ref *ref, void *cookie, off_t offset,
 
 static status_t
 write_to_file(file_cache_ref *ref, void *cookie, off_t offset, int32 pageOffset,
-	addr_t buffer, size_t bufferSize, size_t lastReservedPages,
+	addr_t buffer, size_t bufferSize, bool useBuffer, size_t lastReservedPages,
 	size_t reservePages)
 {
+	size_t chunkSize;
+	if (!useBuffer) {
+		// we need to allocate a zero buffer
+		// TODO: use smaller buffers if this fails
+		chunkSize = min_c(bufferSize, B_PAGE_SIZE);
+		buffer = (addr_t)malloc(chunkSize);
+		if (buffer == 0)
+			return B_NO_MEMORY;
+
+		memset((void *)buffer, 0, chunkSize);
+	}
+
 	iovec vec;
 	vec.iov_base = (void *)buffer;
 	vec.iov_len = bufferSize;
@@ -465,8 +485,26 @@ write_to_file(file_cache_ref *ref, void *cookie, off_t offset, int32 pageOffset,
 	mutex_unlock(&ref->cache->lock);
 	vm_page_unreserve_pages(lastReservedPages);
 
-	status_t status = vfs_write_pages(ref->vnode, cookie, offset + pageOffset,
+	status_t status;
+
+	if (!useBuffer) {
+		while (bufferSize > 0) {
+			if (bufferSize < chunkSize)
+				chunkSize = bufferSize;
+
+			status = vfs_write_pages(ref->vnode, cookie, offset + pageOffset,
+				&vec, 1, &chunkSize, false);
+			if (status < B_OK)
+				break;
+
+			bufferSize -= chunkSize;
+			pageOffset += chunkSize;
+		}
+	} else {
+		status = vfs_write_pages(ref->vnode, cookie, offset + pageOffset,
 			&vec, 1, &bufferSize, false);
+	}
+
 	if (status == B_OK)
 		reserve_pages(ref, reservePages, true);
 
@@ -478,9 +516,10 @@ write_to_file(file_cache_ref *ref, void *cookie, off_t offset, int32 pageOffset,
 
 static inline status_t
 satisfy_cache_io(file_cache_ref *ref, void *cookie, cache_func function,
-	off_t offset, addr_t buffer, int32 &pageOffset, size_t bytesLeft,
+	off_t offset, addr_t buffer, bool useBuffer, int32 &pageOffset,
-	size_t &reservePages, off_t &lastOffset, addr_t &lastBuffer,
+	size_t bytesLeft, size_t &reservePages, off_t &lastOffset,
-	int32 &lastPageOffset, size_t &lastLeft, size_t &lastReservedPages)
+	addr_t &lastBuffer, int32 &lastPageOffset, size_t &lastLeft,
+	size_t &lastReservedPages)
 {
 	if (lastBuffer == buffer)
 		return B_OK;
@@ -490,7 +529,7 @@ satisfy_cache_io(file_cache_ref *ref, void *cookie, cache_func function,
 		+ lastPageOffset + B_PAGE_SIZE - 1) >> PAGE_SHIFT);
 
 	status_t status = function(ref, cookie, lastOffset, lastPageOffset,
-		lastBuffer, requestSize, lastReservedPages, reservePages);
+		lastBuffer, requestSize, useBuffer, lastReservedPages, reservePages);
 	if (status == B_OK) {
 		lastReservedPages = reservePages;
 		lastBuffer = buffer;
@@ -513,6 +552,7 @@ cache_io(void *_cacheRef, void *cookie, off_t offset, addr_t buffer,
 	file_cache_ref *ref = (file_cache_ref *)_cacheRef;
 	vm_cache *cache = ref->cache;
 	off_t fileSize = cache->virtual_size;
+	bool useBuffer = buffer != 0;
 
 	TRACE(("cache_io(ref = %p, offset = %Ld, buffer = %p, size = %lu, %s)\n",
 		ref, offset, (void *)buffer, *_size, doWrite ? "write" : "read"));
@@ -575,8 +615,9 @@ cache_io(void *_cacheRef, void *cookie, off_t offset, addr_t buffer,
 			// we didn't get yet (to make sure no one else interferes in the
 			// mean time).
 			status_t status = satisfy_cache_io(ref, cookie, function, offset,
-				buffer, pageOffset, bytesLeft, reservePages, lastOffset,
+				buffer, useBuffer, pageOffset, bytesLeft, reservePages,
-				lastBuffer, lastPageOffset, lastLeft, lastReservedPages);
+				lastOffset, lastBuffer, lastPageOffset, lastLeft,
+				lastReservedPages);
 			if (status != B_OK)
 				return status;
 
@@ -606,13 +647,18 @@ cache_io(void *_cacheRef, void *cookie, off_t offset, addr_t buffer,
 
 			// and copy the contents of the page already in memory
 			if (doWrite) {
+				if (useBuffer) {
 					user_memcpy((void *)(virtualAddress + pageOffset),
 						(void *)buffer, bytesInPage);
+				} else {
+					user_memset((void *)(virtualAddress + pageOffset),
+						0, bytesInPage);
+				}
 
 				// make sure the page is in the modified list
 				if (page->state != PAGE_STATE_MODIFIED)
 					vm_page_set_state(page, PAGE_STATE_MODIFIED);
-			} else {
+			} else if (useBuffer) {
 				user_memcpy((void *)buffer,
 					(void *)(virtualAddress + pageOffset), bytesInPage);
 			}
@@ -643,8 +689,9 @@ cache_io(void *_cacheRef, void *cookie, off_t offset, addr_t buffer,
 
 		if (buffer - lastBuffer + lastPageOffset >= kMaxChunkSize) {
 			status_t status = satisfy_cache_io(ref, cookie, function, offset,
-				buffer, pageOffset, bytesLeft, reservePages, lastOffset,
+				buffer, useBuffer, pageOffset, bytesLeft, reservePages,
-				lastBuffer, lastPageOffset, lastLeft, lastReservedPages);
+				lastOffset, lastBuffer, lastPageOffset, lastLeft,
+				lastReservedPages);
 			if (status != B_OK)
 				return status;
 		}
@@ -653,7 +700,7 @@ cache_io(void *_cacheRef, void *cookie, off_t offset, addr_t buffer,
 	// fill the last remaining bytes of the request (either write or read)
 
 	return function(ref, cookie, lastOffset, lastPageOffset, lastBuffer,
-		lastLeft, lastReservedPages, 0);
+		lastLeft, useBuffer, lastReservedPages, 0);
 }