Cleanup block processor flag handling

First, remove the "Don't checksum" flag, fragment blocks also need to
be checksumed and are also subject to deduplication. For sentinel
blocks, instead check if the size is zero.

Second, cleanly seperate the user settable flags from the non-user
settable flags and reject any block that has non-user settable or
unknown flags set.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

5 files changed, 38 insertions, 26 deletions

diff --git a/include/sqfs/block_processor.h b/include/sqfs/block_processor.h
index 562c4d2..2086a3d 100644
--- a/include/sqfs/block_processor.h
+++ b/include/sqfs/block_processor.h
@@ -55,29 +55,14 @@ typedef enum {
 	SQFS_BLK_DONT_COMPRESS = 0x0001,
 
 	/**
-	 * @brief Set by compressor worker if the block was actually compressed.
-	 */
-	SQFS_BLK_IS_COMPRESSED = 0x0002,
-
-	/**
-	 * @brief Do not calculate block checksum.
-	 */
-	SQFS_BLK_DONT_CHECKSUM = 0x0004,
-
-	/**
-	 * @brief Set by compressor worker if compression failed.
-	 */
-	SQFS_BLK_COMPRESS_ERROR = 0x0008,
-
-	/**
 	 * @brief Indicates that an equeued block is the first block of a file.
 	 */
-	SQFS_BLK_FIRST_BLOCK = 0x0010,
+	SQFS_BLK_FIRST_BLOCK = 0x0002,
 
 	/**
 	 * @brief Indicates that an equeued block is the last block of a file.
 	 */
-	SQFS_BLK_LAST_BLOCK = 0x0020,
+	SQFS_BLK_LAST_BLOCK = 0x0004,
 
 	/**
 	 * @brief Allign the block on disk to device block size.
@@ -89,14 +74,29 @@ typedef enum {
 	 * If used with @ref SQFS_BLK_LAST_BLOCK, the output file is padded
 	 * after writing the block.
 	 */
-	SQFS_BLK_ALLIGN = 0x0040,
+	SQFS_BLK_ALLIGN = 0x0008,
 
 	/**
 	 * @brief Indicates that a block is not part of a file but contains
 	 *        file tail ends and an entry in the fragment table has to be
 	 *        added.
 	 */
-	SQFS_BLK_FRAGMENT_BLOCK = 0x0080,
+	SQFS_BLK_FRAGMENT_BLOCK = 0x0010,
+
+	/**
+	 * @brief Set by compressor worker if the block was actually compressed.
+	 */
+	SQFS_BLK_IS_COMPRESSED = 0x4000,
+
+	/**
+	 * @brief Set by compressor worker if compression failed.
+	 */
+	SQFS_BLK_COMPRESS_ERROR = 0x8000,
+
+	/**
+	 * @brief The combination of all flags that are user settable.
+	 */
+	SQFS_BLK_USER_SETTABLE_FLAGS = 0x001F,
 } E_SQFS_BLK_FLAGS;
 
 /**
diff --git a/lib/sqfs/blk_proc/process_block.c b/lib/sqfs/blk_proc/process_block.c
index 0747bc5..5d1fa58 100644
--- a/lib/sqfs/blk_proc/process_block.c
+++ b/lib/sqfs/blk_proc/process_block.c
@@ -15,8 +15,7 @@ int sqfs_block_process(sqfs_block_t *block, sqfs_compressor_t *cmp,
 {
 	ssize_t ret;
 
-	if (!(block->flags & SQFS_BLK_DONT_CHECKSUM))
-		block->checksum = crc32(0, block->data, block->size);
+	block->checksum = crc32(0, block->data, block->size);
 
 	if (!(block->flags & SQFS_BLK_DONT_COMPRESS)) {
 		ret = cmp->do_block(cmp, block->data, block->size,
diff --git a/lib/sqfs/blk_proc/pthread.c b/lib/sqfs/blk_proc/pthread.c
index a9cffd0..f1874c0 100644
--- a/lib/sqfs/blk_proc/pthread.c
+++ b/lib/sqfs/blk_proc/pthread.c
@@ -193,12 +193,15 @@ int sqfs_block_processor_enqueue(sqfs_block_processor_t *proc,
 {
 	sqfs_block_t *queue = NULL, *it, *prev;
 
+	if (block->flags & ~SQFS_BLK_USER_SETTABLE_FLAGS)
+		return SQFS_ERROR_UNSUPPORTED;
+
 	block->sequence_number = proc->enqueue_id++;
 	block->next = NULL;
 
 	pthread_mutex_lock(&proc->mtx);
-	if ((block->flags & SQFS_BLK_DONT_COMPRESS) &&
-	    (block->flags & SQFS_BLK_DONT_CHECKSUM)) {
+	if (block->size == 0) {
+		block->checksum = 0;
 		store_completed_block(proc, block);
 	} else {
 		while (proc->backlog > proc->max_backlog)
diff --git a/lib/sqfs/blk_proc/serial.c b/lib/sqfs/blk_proc/serial.c
index b6c17fb..b7bc545 100644
--- a/lib/sqfs/blk_proc/serial.c
+++ b/lib/sqfs/blk_proc/serial.c
@@ -51,8 +51,18 @@ int sqfs_block_processor_enqueue(sqfs_block_processor_t *proc,
 		return proc->status;
 	}
 
-	proc->status = sqfs_block_process(block, proc->cmp,
-					  proc->scratch, proc->max_block_size);
+	if (block->flags & ~SQFS_BLK_USER_SETTABLE_FLAGS) {
+		proc->status = SQFS_ERROR_UNSUPPORTED;
+		return proc->status;
+	}
+
+	if (block->size == 0) {
+		block->checksum = 0;
+	} else {
+		proc->status = sqfs_block_process(block, proc->cmp,
+						  proc->scratch,
+						  proc->max_block_size);
+	}
 
 	block->next = NULL;
 	return process_completed_blocks(proc, block);
diff --git a/lib/sqfshelper/data_writer.c b/lib/sqfshelper/data_writer.c
index f5e22f3..3163c4e 100644
--- a/lib/sqfshelper/data_writer.c
+++ b/lib/sqfshelper/data_writer.c
@@ -151,7 +151,7 @@ static int add_sentinel_block(data_writer_t *data, sqfs_inode_generic_t *inode,
 	}
 
 	blk->inode = inode;
-	blk->flags = SQFS_BLK_DONT_COMPRESS | SQFS_BLK_DONT_CHECKSUM | flags;
+	blk->flags = flags;
 
 	return sqfs_block_processor_enqueue(data->proc, blk);
 }