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* You can now create the block cache in read-only mode (using an additional

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parameter during construction).
* Doing so will now result in a kernel panic whenever your file system tries to
  write to a block.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@18719 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler
2006-08-30 23:18:31 +00:00
parent 03a2985277
commit 9b906ccf04
6 changed files with 23 additions and 12 deletions
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src/system/kernel/cache/block_cache.cpp
Vendored
+12 -4
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@@ -149,7 +149,7 @@ cached_block::Hash(void *_cacheEntry, const void *_block, uint32 range)
// #pragma mark - block_cache
block_cache::block_cache(int _fd, off_t numBlocks, size_t blockSize)
block_cache::block_cache(int _fd, off_t numBlocks, size_t blockSize, bool readOnly)
:
hash(NULL),
fd(_fd),
@@ -158,7 +158,8 @@ block_cache::block_cache(int _fd, off_t numBlocks, size_t blockSize)
next_transaction_id(1),
last_transaction(NULL),
transaction_hash(NULL),
ranges_hash(NULL)
ranges_hash(NULL),
read_only(readOnly)
{
hash = hash_init(32, 0, &cached_block::Compare, &cached_block::Hash);
if (hash == NULL)
@@ -1078,9 +1079,9 @@ block_cache_delete(void *_cache, bool allowWrites)
extern "C" void *
block_cache_create(int fd, off_t numBlocks, size_t blockSize)
block_cache_create(int fd, off_t numBlocks, size_t blockSize, bool readOnly)
{
block_cache *cache = new block_cache(fd, numBlocks, blockSize);
block_cache *cache = new block_cache(fd, numBlocks, blockSize, readOnly);
if (cache == NULL)
return NULL;
@@ -1126,6 +1127,9 @@ block_cache_make_writable(void *_cache, off_t blockNumber, int32 transaction)
block_cache *cache = (block_cache *)_cache;
BenaphoreLocker locker(&cache->lock);
if (cache->read_only)
panic("tried to make block writable on a read-only cache!");
// ToDo: this can be done better!
void *block = get_writable_cached_block(cache, blockNumber,
blockNumber, 1, transaction, false);
@@ -1147,6 +1151,8 @@ block_cache_get_writable_etc(void *_cache, off_t blockNumber, off_t base,
TRACE(("block_cache_get_writable_etc(block = %Ld, transaction = %ld)\n",
blockNumber, transaction));
if (cache->read_only)
panic("tried to get writable block on a read-only cache!");
return get_writable_cached_block(cache, blockNumber, base, length,
transaction, false);
@@ -1169,6 +1175,8 @@ block_cache_get_empty(void *_cache, off_t blockNumber, int32 transaction)
TRACE(("block_cache_get_empty(block = %Ld, transaction = %ld)\n",
blockNumber, transaction));
if (cache->read_only)
panic("tried to get empty writable block on a read-only cache!");
return get_writable_cached_block((block_cache *)_cache, blockNumber,
blockNumber, 1, transaction, true);