On 05/14/2013 03:10 PM, MORITA Kazutaka wrote:
> The contents of read-only objects are immutable. We can cache their
> sha1 digests as extended attributes for the next sha1 calculation.
> With this patch, I can complete 'collie vdi check' of a 4 GB snapshot
> volume in 0.2 seconds.
>
> Signed-off-by: MORITA Kazutaka <[email protected]>
> ---
>
> This patch is against my "use hash for vdi check and object recovery" series.
>
> sheep/farm/farm.c | 5 -----
> sheep/plain_store.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 49 insertions(+), 5 deletions(-)
>
> diff --git a/sheep/farm/farm.c b/sheep/farm/farm.c
> index c31c501..38586f5 100644
> --- a/sheep/farm/farm.c
> +++ b/sheep/farm/farm.c
> @@ -98,11 +98,6 @@ static int farm_init(void)
> if (create_directory(obj_path) < 0)
> goto err;
>
> - if (!is_xattr_enabled(obj_path)) {
> - sd_eprintf("xattrs are not enabled on %s", obj_path);
> - goto err;
> - }
> -
> if (snap_init() < 0)
> goto err;
>
> diff --git a/sheep/plain_store.c b/sheep/plain_store.c
> index 3b71467..5f0a131 100644
> --- a/sheep/plain_store.c
> +++ b/sheep/plain_store.c
> @@ -12,6 +12,7 @@
> #include <fcntl.h>
> #include <sys/stat.h>
> #include <sys/types.h>
> +#include <sys/xattr.h>
> #include <unistd.h>
> #include <libgen.h>
>
> @@ -220,6 +221,12 @@ int default_init(void)
> int ret;
>
> sd_dprintf("use plain store driver");
> +
> + if (!is_xattr_enabled(obj_path)) {
> + sd_eprintf("xattrs are not enabled on %s", obj_path);
> + return SD_RES_EIO;
> + }
> +
> ret = for_each_obj_path(make_stale_dir);
> if (ret != SD_RES_SUCCESS)
> return ret;
> @@ -476,6 +483,41 @@ int default_remove_object(uint64_t oid)
> return SD_RES_SUCCESS;
> }
>
> +#define SHA1NAME "user.obj.sha1"
> +
> +static int get_sha1_cache(uint64_t oid, uint32_t epoch, uint8_t *sha1)
> +{
> + char path[PATH_MAX];
> +
> + if (!oid_is_readonly(oid))
> + return -1;
> +
> + if (default_exist(oid))
> + get_obj_path(oid, path);
> + else
> + get_stale_obj_path(oid, epoch, path);
> +
> + if (getxattr(path, SHA1NAME, sha1, SHA1_LEN) != SHA1_LEN)
> + return -1;
> +
> + return 0;
> +}
> +
> +static int set_sha1_cache(uint64_t oid, uint32_t epoch, const uint8_t *sha1)
> +{
> + char path[PATH_MAX];
> +
> + if (!oid_is_readonly(oid))
> + return -1;
> +
Stale object isn't marked readonly yet. So your patch won't be useful
for recovery?
> + if (default_exist(oid))
> + get_obj_path(oid, path);
> + else
> + get_stale_obj_path(oid, epoch, path);
> +
> + return setxattr(path, SHA1NAME, sha1, SHA1_LEN, 0);
setxattr can fail, need failure handling.
> +}
> +
> int default_get_hash(uint64_t oid, uint32_t epoch, uint8_t *sha1)
> {
> int ret;
> @@ -485,6 +527,11 @@ int default_get_hash(uint64_t oid, uint32_t epoch,
> uint8_t *sha1)
> uint64_t offset = 0;
> uint32_t length;
>
> + if (get_sha1_cache(oid, epoch, sha1) == 0) {
> + sd_dprintf("use cached sha1 digest %s", sha1_to_hex(sha1));
> + return SD_RES_SUCCESS;
> + }
> +
> length = get_objsize(oid);
> buf = malloc(length);
> if (buf == NULL)
> @@ -512,6 +559,8 @@ int default_get_hash(uint64_t oid, uint32_t epoch,
> uint8_t *sha1)
> sd_dprintf("the message digest of %"PRIx64" at epoch %d is %s", oid,
> epoch, sha1_to_hex(sha1));
>
> + set_sha1_cache(oid, epoch, sha1);
Better name as get/set_object_sha1() and put oid_is_readonly() check in
the default_get_hash() will make the code better readability.
Thanks,
Yuan
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