raid5-ppl: support disk hot add/remove with PPL

Add a function to modify the log by removing an rdev when a drive fails
or adding when a spare/replacement is activated as a raid member.

Removing a disk just clears the child log rdev pointer. No new stripes
will be accepted for this child log in ppl_write_stripe() and running io
units will be processed without writing PPL to the device.

Adding a disk sets the child log rdev pointer and writes an empty PPL
header.

Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
Signed-off-by: Shaohua Li <shli@fb.com>

diff --git a/drivers/md/raid5-log.h b/drivers/md/raid5-log.h
index a67fb58..4f5a0f4 100644 (file)
--- a/drivers/md/raid5-log.h
+++ b/drivers/md/raid5-log.h
@@ -39,6 +39,7 @@ extern void ppl_exit_log(struct r5conf *conf);
 extern int ppl_write_stripe(struct r5conf *conf, struct stripe_head *sh);
 extern void ppl_write_stripe_run(struct r5conf *conf);
 extern void ppl_stripe_write_finished(struct stripe_head *sh);
+extern int ppl_modify_log(struct r5conf *conf, struct md_rdev *rdev, bool add);
 
 static inline bool raid5_has_ppl(struct r5conf *conf)
 {
@@ -102,4 +103,12 @@ static inline int log_init(struct r5conf *conf, struct md_rdev *journal_dev)
        return 0;
 }
 
+static inline int log_modify(struct r5conf *conf, struct md_rdev *rdev, bool add)
+{
+       if (raid5_has_ppl(conf))
+               return ppl_modify_log(conf, rdev, add);
+
+       return 0;
+}
+
 #endif

diff --git a/drivers/md/raid5-ppl.c b/drivers/md/raid5-ppl.c
index d336c02..4af420f 100644 (file)
--- a/drivers/md/raid5-ppl.c
+++ b/drivers/md/raid5-ppl.c
@@ -400,6 +400,13 @@ static void ppl_submit_iounit(struct ppl_io_unit *io)
        struct stripe_head *sh;
        int i;
 
+       bio->bi_private = io;
+
+       if (!log->rdev || test_bit(Faulty, &log->rdev->flags)) {
+               ppl_log_endio(bio);
+               return;
+       }
+
        for (i = 0; i < io->entries_count; i++) {
                struct ppl_header_entry *e = &pplhdr->entries[i];
 
@@ -415,7 +422,6 @@ static void ppl_submit_iounit(struct ppl_io_unit *io)
        pplhdr->entries_count = cpu_to_le32(io->entries_count);
        pplhdr->checksum = cpu_to_le32(~crc32c_le(~0, pplhdr, PPL_HEADER_SIZE));
 
-       bio->bi_private = io;
        bio->bi_end_io = ppl_log_endio;
        bio->bi_opf = REQ_OP_WRITE | REQ_FUA;
        bio->bi_bdev = log->rdev->bdev;
@@ -1190,3 +1196,40 @@ err:
        __ppl_exit_log(ppl_conf);
        return ret;
 }
+
+int ppl_modify_log(struct r5conf *conf, struct md_rdev *rdev, bool add)
+{
+       struct ppl_conf *ppl_conf = conf->log_private;
+       struct ppl_log *log;
+       int ret = 0;
+       char b[BDEVNAME_SIZE];
+
+       if (!rdev)
+               return -EINVAL;
+
+       pr_debug("%s: disk: %d operation: %s dev: %s\n",
+                __func__, rdev->raid_disk, add ? "add" : "remove",
+                bdevname(rdev->bdev, b));
+
+       if (rdev->raid_disk < 0)
+               return 0;
+
+       if (rdev->raid_disk >= ppl_conf->count)
+               return -ENODEV;
+
+       log = &ppl_conf->child_logs[rdev->raid_disk];
+
+       mutex_lock(&log->io_mutex);
+       if (add) {
+               ret = ppl_validate_rdev(rdev);
+               if (!ret) {
+                       log->rdev = rdev;
+                       ret = ppl_write_empty_header(log);
+               }
+       } else {
+               log->rdev = NULL;
+       }
+       mutex_unlock(&log->io_mutex);
+
+       return ret;
+}

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 78ed574..6760af2 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -7648,6 +7648,11 @@ static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
                        *rdevp = rdev;
                }
        }
+       if (!err) {
+               err = log_modify(conf, rdev, false);
+               if (err)
+                       goto abort;
+       }
        if (p->replacement) {
                /* We must have just cleared 'rdev' */
                p->rdev = p->replacement;
@@ -7657,6 +7662,9 @@ static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
                           */
                p->replacement = NULL;
                clear_bit(WantReplacement, &rdev->flags);
+
+               if (!err)
+                       err = log_modify(conf, p->rdev, true);
        } else
                /* We might have just removed the Replacement as faulty-
                 * clear the bit just in case
@@ -7713,10 +7721,12 @@ static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev)
                if (p->rdev == NULL) {
                        clear_bit(In_sync, &rdev->flags);
                        rdev->raid_disk = disk;
-                       err = 0;
                        if (rdev->saved_raid_disk != disk)
                                conf->fullsync = 1;
                        rcu_assign_pointer(p->rdev, rdev);
+
+                       err = log_modify(conf, rdev, true);
+
                        goto out;
                }
        }