[Mesa-dev] [PATCH 2/2] disk_cache: use block size rather than file size

[Timothy Arceri]

The majority of cache files are less than 1kb this resulted in us
greatly miscalculating the amount of disk space used by the cache.

Using the number of blocks allocated to the file is more
conservative and less likely to cause issues.

This change will result in cache sizes being miscalculated further
until old items added with the previous calculation have all been
removed. However I don't see anyway around that, the previous
patch should help limit that problem.

Cc: "17.1" <mesa-stable at lists.freedesktop.org>
---
 src/util/disk_cache.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/src/util/disk_cache.c b/src/util/disk_cache.c
index 9fd7b96..2764017 100644
--- a/src/util/disk_cache.c
+++ b/src/util/disk_cache.c
@@ -525,21 +525,21 @@ unlink_lru_file_from_directory(const char *path)
       return 0;
 
    if (stat(filename, &sb) == -1) {
       free (filename);
       return 0;
    }
 
    unlink(filename);
    free (filename);
 
-   return sb.st_size;
+   return sb.st_blocks * 512;
 }
 
 /* Is entry a directory with a two-character name, (and not the
  * special name of ".."). We also return false if the dir is empty.
  */
 static bool
 is_two_character_sub_directory(const char *path, const struct stat *sb,
                                const char *d_name, const size_t len)
 {
    if (!S_ISDIR(sb->st_mode))
@@ -630,22 +630,22 @@ disk_cache_remove(struct disk_cache *cache, const cache_key key)
    }
 
    if (stat(filename, &sb) == -1) {
       free(filename);
       return;
    }
 
    unlink(filename);
    free(filename);
 
-   if (sb.st_size)
-      p_atomic_add(cache->size, - (uint64_t)sb.st_size);
+   if (sb.st_blocks * 512)
+      p_atomic_add(cache->size, - (uint64_t)sb.st_blocks * 512);
 }
 
 static ssize_t
 read_all(int fd, void *buf, size_t count)
 {
    char *in = buf;
    ssize_t read_ret;
    size_t done;
 
    for (done = 0; done < count; done += read_ret) {
@@ -873,22 +873,28 @@ cache_put(void *job, int thread_index)
    if (file_size == 0) {
       unlink(filename_tmp);
       goto done;
    }
    ret = rename(filename_tmp, filename);
    if (ret == -1) {
       unlink(filename_tmp);
       goto done;
    }
 
-   file_size += cf_data_size + dc_job->cache->driver_keys_blob_size;
-   p_atomic_add(dc_job->cache->size, file_size);
+   struct stat sb;
+   if (stat(filename, &sb) == -1) {
+      /* Something went wrong remove the file */
+      unlink(filename);
+      goto done;
+   }
+
+   p_atomic_add(dc_job->cache->size, sb.st_blocks * 512);
 
  done:
    if (fd_final != -1)
       close(fd_final);
    /* This close finally releases the flock, (now that the final file
     * has been renamed into place and the size has been added).
     */
    if (fd != -1)
       close(fd);
    if (filename_tmp)
-- 
2.9.3