util/fossilize_db: Add extra flock mutex.
The flock is per-fd, not per thread, and we do it outside of the main mutex. This was
done to avoid having to wait in the mutex, but we can get a case where one ends up running
the body with the flock unlocked.
Fix this by adding a mutex that doesn't need to be locked for reads.
Fixes: 4f0f8133a3
"util/fossilize_db: Do not lock the fossilize db permanently."
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12266>
This commit is contained in:
parent
75266ee44a
commit
30a359d633
|
@ -286,6 +286,7 @@ foz_prepare(struct foz_db *foz_db, char *cache_path)
|
||||||
return false;
|
return false;
|
||||||
|
|
||||||
simple_mtx_init(&foz_db->mtx, mtx_plain);
|
simple_mtx_init(&foz_db->mtx, mtx_plain);
|
||||||
|
simple_mtx_init(&foz_db->flock_mtx, mtx_plain);
|
||||||
foz_db->mem_ctx = ralloc_context(NULL);
|
foz_db->mem_ctx = ralloc_context(NULL);
|
||||||
foz_db->index_db = _mesa_hash_table_u64_create(NULL);
|
foz_db->index_db = _mesa_hash_table_u64_create(NULL);
|
||||||
|
|
||||||
|
@ -348,6 +349,7 @@ foz_destroy(struct foz_db *foz_db)
|
||||||
if (foz_db->mem_ctx) {
|
if (foz_db->mem_ctx) {
|
||||||
_mesa_hash_table_u64_destroy(foz_db->index_db);
|
_mesa_hash_table_u64_destroy(foz_db->index_db);
|
||||||
ralloc_free(foz_db->mem_ctx);
|
ralloc_free(foz_db->mem_ctx);
|
||||||
|
simple_mtx_destroy(&foz_db->flock_mtx);
|
||||||
simple_mtx_destroy(&foz_db->mtx);
|
simple_mtx_destroy(&foz_db->mtx);
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
@ -434,7 +436,12 @@ foz_write_entry(struct foz_db *foz_db, const uint8_t *cache_key_160bit,
|
||||||
if (!foz_db->alive)
|
if (!foz_db->alive)
|
||||||
return false;
|
return false;
|
||||||
|
|
||||||
/* Wait for 1 second. This is done outside of the mutex as I believe there is more potential
|
/* The flock is per-fd, not per thread, we do it outside of the main mutex to avoid having to
|
||||||
|
* wait in the mutex potentially blocking reads. We use the secondary flock_mtx to stop race
|
||||||
|
* conditions between the write threads sharing the same file descriptor. */
|
||||||
|
simple_mtx_lock(&foz_db->flock_mtx);
|
||||||
|
|
||||||
|
/* Wait for 1 second. This is done outside of the main mutex as I believe there is more potential
|
||||||
* for file contention than mtx contention of significant length. */
|
* for file contention than mtx contention of significant length. */
|
||||||
int err = lock_file_with_timeout(foz_db->file[0], 1000000000);
|
int err = lock_file_with_timeout(foz_db->file[0], 1000000000);
|
||||||
if (err == -1)
|
if (err == -1)
|
||||||
|
@ -449,6 +456,7 @@ foz_write_entry(struct foz_db *foz_db, const uint8_t *cache_key_160bit,
|
||||||
if (entry) {
|
if (entry) {
|
||||||
simple_mtx_unlock(&foz_db->mtx);
|
simple_mtx_unlock(&foz_db->mtx);
|
||||||
flock(fileno(foz_db->file[0]), LOCK_UN);
|
flock(fileno(foz_db->file[0]), LOCK_UN);
|
||||||
|
simple_mtx_unlock(&foz_db->flock_mtx);
|
||||||
return NULL;
|
return NULL;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -511,6 +519,7 @@ foz_write_entry(struct foz_db *foz_db, const uint8_t *cache_key_160bit,
|
||||||
|
|
||||||
simple_mtx_unlock(&foz_db->mtx);
|
simple_mtx_unlock(&foz_db->mtx);
|
||||||
flock(fileno(foz_db->file[0]), LOCK_UN);
|
flock(fileno(foz_db->file[0]), LOCK_UN);
|
||||||
|
simple_mtx_unlock(&foz_db->flock_mtx);
|
||||||
|
|
||||||
return true;
|
return true;
|
||||||
|
|
||||||
|
@ -518,6 +527,7 @@ fail:
|
||||||
simple_mtx_unlock(&foz_db->mtx);
|
simple_mtx_unlock(&foz_db->mtx);
|
||||||
fail_file:
|
fail_file:
|
||||||
flock(fileno(foz_db->file[0]), LOCK_UN);
|
flock(fileno(foz_db->file[0]), LOCK_UN);
|
||||||
|
simple_mtx_unlock(&foz_db->flock_mtx);
|
||||||
return false;
|
return false;
|
||||||
}
|
}
|
||||||
#else
|
#else
|
||||||
|
|
|
@ -76,6 +76,7 @@ struct foz_db {
|
||||||
FILE *file[FOZ_MAX_DBS]; /* An array of all foz dbs */
|
FILE *file[FOZ_MAX_DBS]; /* An array of all foz dbs */
|
||||||
FILE *db_idx; /* The default writable foz db idx */
|
FILE *db_idx; /* The default writable foz db idx */
|
||||||
simple_mtx_t mtx; /* Mutex for file/hash table read/writes */
|
simple_mtx_t mtx; /* Mutex for file/hash table read/writes */
|
||||||
|
simple_mtx_t flock_mtx; /* Mutex for flocking the file for writes */
|
||||||
void *mem_ctx;
|
void *mem_ctx;
|
||||||
struct hash_table_u64 *index_db; /* Hash table of all foz db entries */
|
struct hash_table_u64 *index_db; /* Hash table of all foz db entries */
|
||||||
bool alive;
|
bool alive;
|
||||||
|
|
Loading…
Reference in New Issue