On Wed, Mar 1, 2017 at 7:25 AM, Timothy Arceri <tarc...@itsqueeze.com> wrote:
> ---
> src/util/disk_cache.c | 37 ++++++++++++++++++++++++++++++++++---
> 1 file changed, 34 insertions(+), 3 deletions(-)
>
> diff --git a/src/util/disk_cache.c b/src/util/disk_cache.c
> index f5e1145..2a0edca 100644
> --- a/src/util/disk_cache.c
> +++ b/src/util/disk_cache.c
> @@ -31,20 +31,21 @@
> #include <sys/file.h>
> #include <sys/types.h>
> #include <sys/stat.h>
> #include <sys/mman.h>
> #include <unistd.h>
> #include <fcntl.h>
> #include <pwd.h>
> #include <errno.h>
> #include <dirent.h>
>
> +#include "util/crc32.h"
> #include "util/u_atomic.h"
> #include "util/mesa-sha1.h"
> #include "util/ralloc.h"
> #include "main/errors.h"
>
> #include "disk_cache.h"
>
> /* Number of bits to mask off from a cache key to get an index. */
> #define CACHE_INDEX_KEY_BITS 16
>
> @@ -702,34 +703,48 @@ disk_cache_put(struct disk_cache *cache,
> /* OK, we're now on the hook to write out a file that we know is
> * not in the cache, and is also not being written out to the cache
> * by some other process.
> *
> * Before we do that, if the cache is too large, evict something
> * else first.
> */
> if (*cache->size + size > cache->max_size)
> evict_random_item(cache);
>
> + /* Create CRC of the data and store at the start of the file. We will
> + * read this when restoring the cache and use it to check for corruption.
> + */
> + uint32_t crc32 = util_hash_crc32(data, size);
> + size_t crc_size = sizeof(crc32);
> + for (len = 0; len < crc_size; len += ret) {
> + ret = write(fd, &crc32, crc_size - len);
I think you need to advance the data pointer if retrying. There is
also a case of EINTR where you should be retrying on error (ret ==
-1). Might be worth making a helper function.
> + if (ret == -1) {
> + unlink(filename_tmp);
> + goto done;
> + }
> + }
> +
> /* Now, finally, write out the contents to the temporary file, then
> * rename them atomically to the destination filename, and also
> * perform an atomic increment of the total cache size.
> */
> for (len = 0; len < size; len += ret) {
> ret = write(fd, p + len, size - len);
> if (ret == -1) {
> unlink(filename_tmp);
> goto done;
> }
> }
>
> rename(filename_tmp, filename);
>
> + size += crc_size;
> p_atomic_add(cache->size, size);
>
> done:
> if (fd_final != -1)
> close(fd_final);
> /* This close finally releases the flock, (now that the final dile
> * has been renamed into place and the size has been added).
> */
> if (fd != -1)
> close(fd);
> @@ -758,31 +773,47 @@ disk_cache_get(struct disk_cache *cache, cache_key key,
> size_t *size)
> if (fd == -1)
> goto fail;
>
> if (fstat(fd, &sb) == -1)
> goto fail;
>
> data = malloc(sb.st_size);
> if (data == NULL)
> goto fail;
>
> - for (len = 0; len < sb.st_size; len += ret) {
> - ret = read(fd, data + len, sb.st_size - len);
> + /* Load the CRC that was created when the file was written. */
> + uint32_t crc32;
> + size_t crc_size = sizeof(crc32);
> + assert(sb.st_size > crc_size);
> + for (len = 0; len < crc_size; len += ret) {
> + ret = read(fd, &crc32 + len, crc_size - len);
&crc32 + len doesn't look right, it's a uint32_t * pointer. EINTR
handling is also missing.
GraÅžvydas
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