From: Heinz Mauelshagen <heinzm@xxxxxxxxxx>
Upstream commit 2ded370373a400c20cf0c6e941e724e61582a867
started the addition of "write-back" mode to MD (raid5-cache),
i.e. support write-back caching on the raid journal device.
In order to allow the dm-raid target to switch between
the available "write-through" and "write-back" modes,
provide new r5c_journal_mode_set() API.
Use the new API in existing r5c_journal_mode_store()
Signed-off-by: Heinz Mauelshagen <heinzm@xxxxxxxxxx>
---
drivers/md/raid5-cache.c | 62 ++++++++++++++++++++++++++----------------------
drivers/md/raid5.h | 11 +++++++++
2 files changed, 45 insertions(+), 28 deletions(-)
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index 3f307be..218b6f3 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -53,16 +53,6 @@
*/
#define R5L_POOL_SIZE 4
-/*
- * r5c journal modes of the array: write-back or write-through.
- * write-through mode has identical behavior as existing log only
- * implementation.
- */
-enum r5c_journal_mode {
- R5C_JOURNAL_MODE_WRITE_THROUGH = 0,
- R5C_JOURNAL_MODE_WRITE_BACK = 1,
-};
-
static char *r5c_journal_mode_str[] = {"write-through",
"write-back"};
/*
@@ -2327,40 +2317,56 @@ static ssize_t r5c_journal_mode_show(struct mddev *mddev, char *page)
return ret;
}
-static ssize_t r5c_journal_mode_store(struct mddev *mddev,
- const char *page, size_t length)
+/*
+ * Set journal cache mode on @mddev (external API initially needed by dm-raid).
+ *
+ * @mode as defined in 'enum r5c_journal_mode'.
+ *
+ */
+int r5c_journal_mode_set(struct mddev *mddev, int mode)
{
struct r5conf *conf = mddev->private;
struct r5l_log *log = conf->log;
- int val = -1, i;
- int len = length;
if (!log)
return -ENODEV;
- if (len && page[len - 1] == '\n')
- len -= 1;
- for (i = 0; i < ARRAY_SIZE(r5c_journal_mode_str); i++)
- if (strlen(r5c_journal_mode_str[i]) == len &&
- strncmp(page, r5c_journal_mode_str[i], len) == 0) {
- val = i;
- break;
- }
- if (val < R5C_JOURNAL_MODE_WRITE_THROUGH ||
- val > R5C_JOURNAL_MODE_WRITE_BACK)
+ if (mode < R5C_JOURNAL_MODE_WRITE_THROUGH ||
+ mode > R5C_JOURNAL_MODE_WRITE_BACK)
return -EINVAL;
if (raid5_calc_degraded(conf) > 0 &&
- val == R5C_JOURNAL_MODE_WRITE_BACK)
+ mode == R5C_JOURNAL_MODE_WRITE_BACK)
return -EINVAL;
mddev_suspend(mddev);
- conf->log->r5c_journal_mode = val;
+ conf->log->r5c_journal_mode = mode;
mddev_resume(mddev);
pr_debug("md/raid:%s: setting r5c cache mode to %d: %s\n",
- mdname(mddev), val, r5c_journal_mode_str[val]);
- return length;
+ mdname(mddev), mode, r5c_journal_mode_str[mode]);
+ return 0;
+}
+EXPORT_SYMBOL(r5c_journal_mode_set);
+
+static ssize_t r5c_journal_mode_store(struct mddev *mddev,
+ const char *page, size_t length)
+{
+ int mode = ARRAY_SIZE(r5c_journal_mode_str);
+ size_t len = length;
+
+ if (len < 2)
+ return -EINVAL;
+
+ if (page[len - 1] == '\n')
+ len--;
+
+ while (mode--)
+ if (strlen(r5c_journal_mode_str[mode]) == len &&
+ !strncmp(page, r5c_journal_mode_str[mode], len))
+ break;
+
+ return r5c_journal_mode_set(mddev, mode) ?: length;
}
struct md_sysfs_entry
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index 4bb27b9..ec8ca15 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h
@@ -547,6 +547,16 @@ struct r5worker_group {
int stripes_cnt;
};
+/*
+ * r5c journal modes of the array: write-back or write-through.
+ * write-through mode has identical behavior as existing log only
+ * implementation.
+ */
+enum r5c_journal_mode {
+ R5C_JOURNAL_MODE_WRITE_THROUGH = 0,
+ R5C_JOURNAL_MODE_WRITE_BACK = 1,
+};
+
enum r5_cache_state {
R5_INACTIVE_BLOCKED, /* release of inactive stripes blocked,
* waiting for 25% to be free
@@ -795,4 +805,5 @@ extern void r5c_check_cached_full_stripe(struct r5conf *conf);
extern struct md_sysfs_entry r5c_journal_mode;
extern void r5c_update_on_rdev_error(struct mddev *mddev);
extern bool r5c_big_stripe_cached(struct r5conf *conf, sector_t sect);
+extern int r5c_journal_mode_set(struct mddev *mddev, int journal_mode);
#endif
--
2.9.3
--
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