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-rw-r--r--fs/btrfs/bio.c14
-rw-r--r--fs/btrfs/sysfs.c44
-rw-r--r--fs/btrfs/volumes.h24
3 files changed, 81 insertions, 1 deletions
diff --git a/fs/btrfs/bio.c b/fs/btrfs/bio.c
index 960b81718e29..477f350a8bd0 100644
--- a/fs/btrfs/bio.c
+++ b/fs/btrfs/bio.c
@@ -608,8 +608,20 @@ static void run_one_async_done(struct btrfs_work *work, bool do_free)
static bool should_async_write(struct btrfs_bio *bbio)
{
+ bool auto_csum_mode = true;
+
+#ifdef CONFIG_BTRFS_DEBUG
+ struct btrfs_fs_devices *fs_devices = bbio->fs_info->fs_devices;
+ enum btrfs_offload_csum_mode csum_mode = READ_ONCE(fs_devices->offload_csum_mode);
+
+ if (csum_mode == BTRFS_OFFLOAD_CSUM_FORCE_OFF)
+ return false;
+
+ auto_csum_mode = (csum_mode == BTRFS_OFFLOAD_CSUM_AUTO);
+#endif
+
/* Submit synchronously if the checksum implementation is fast. */
- if (test_bit(BTRFS_FS_CSUM_IMPL_FAST, &bbio->fs_info->flags))
+ if (auto_csum_mode && test_bit(BTRFS_FS_CSUM_IMPL_FAST, &bbio->fs_info->flags))
return false;
/*
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index f2681d634302..c6387a8ddb94 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -1307,6 +1307,47 @@ static ssize_t btrfs_bg_reclaim_threshold_store(struct kobject *kobj,
BTRFS_ATTR_RW(, bg_reclaim_threshold, btrfs_bg_reclaim_threshold_show,
btrfs_bg_reclaim_threshold_store);
+#ifdef CONFIG_BTRFS_DEBUG
+static ssize_t btrfs_offload_csum_show(struct kobject *kobj,
+ struct kobj_attribute *a, char *buf)
+{
+ struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
+
+ switch (READ_ONCE(fs_devices->offload_csum_mode)) {
+ case BTRFS_OFFLOAD_CSUM_AUTO:
+ return sysfs_emit(buf, "auto\n");
+ case BTRFS_OFFLOAD_CSUM_FORCE_ON:
+ return sysfs_emit(buf, "1\n");
+ case BTRFS_OFFLOAD_CSUM_FORCE_OFF:
+ return sysfs_emit(buf, "0\n");
+ default:
+ WARN_ON(1);
+ return -EINVAL;
+ }
+}
+
+static ssize_t btrfs_offload_csum_store(struct kobject *kobj,
+ struct kobj_attribute *a, const char *buf,
+ size_t len)
+{
+ struct btrfs_fs_devices *fs_devices = to_fs_devs(kobj);
+ int ret;
+ bool val;
+
+ ret = kstrtobool(buf, &val);
+ if (ret == 0)
+ WRITE_ONCE(fs_devices->offload_csum_mode,
+ val ? BTRFS_OFFLOAD_CSUM_FORCE_ON : BTRFS_OFFLOAD_CSUM_FORCE_OFF);
+ else if (ret == -EINVAL && sysfs_streq(buf, "auto"))
+ WRITE_ONCE(fs_devices->offload_csum_mode, BTRFS_OFFLOAD_CSUM_AUTO);
+ else
+ return -EINVAL;
+
+ return len;
+}
+BTRFS_ATTR_RW(, offload_csum, btrfs_offload_csum_show, btrfs_offload_csum_store);
+#endif
+
/*
* Per-filesystem information and stats.
*
@@ -1326,6 +1367,9 @@ static const struct attribute *btrfs_attrs[] = {
BTRFS_ATTR_PTR(, bg_reclaim_threshold),
BTRFS_ATTR_PTR(, commit_stats),
BTRFS_ATTR_PTR(, temp_fsid),
+#ifdef CONFIG_BTRFS_DEBUG
+ BTRFS_ATTR_PTR(, offload_csum),
+#endif
NULL,
};
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 21d4de0e3f1f..055e095c2f61 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -291,6 +291,25 @@ enum btrfs_read_policy {
BTRFS_NR_READ_POLICY,
};
+#ifdef CONFIG_BTRFS_DEBUG
+/*
+ * Checksum mode - offload it to workqueues or do it synchronously in
+ * btrfs_submit_chunk().
+ */
+enum btrfs_offload_csum_mode {
+ /*
+ * Choose offloading checksum or do it synchronously automatically.
+ * Do it synchronously if the checksum is fast, or offload to workqueues
+ * otherwise.
+ */
+ BTRFS_OFFLOAD_CSUM_AUTO,
+ /* Always offload checksum to workqueues. */
+ BTRFS_OFFLOAD_CSUM_FORCE_ON,
+ /* Never offload checksum to workqueues. */
+ BTRFS_OFFLOAD_CSUM_FORCE_OFF,
+};
+#endif
+
struct btrfs_fs_devices {
u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */
@@ -395,6 +414,11 @@ struct btrfs_fs_devices {
/* Policy used to read the mirrored stripes. */
enum btrfs_read_policy read_policy;
+
+#ifdef CONFIG_BTRFS_DEBUG
+ /* Checksum mode - offload it or do it synchronously. */
+ enum btrfs_offload_csum_mode offload_csum_mode;
+#endif
};
#define BTRFS_MAX_DEVS(info) ((BTRFS_MAX_ITEM_SIZE(info) \