Commit 6358c239 authored by Artur Paszkiewicz's avatar Artur Paszkiewicz Committed by Shaohua Li
Browse files

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: default avatarArtur Paszkiewicz <artur.paszkiewicz@intel.com>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
parent 4536bf9b

drivers/md/raid5-log.h

+9 −0
Original line number Diff line number Diff line
@@ -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

drivers/md/raid5-ppl.c

+44 −1
Original line number Diff line number Diff line
@@ -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;

}

drivers/md/raid5.c

+11 −1
Original line number Diff line number Diff line
@@ -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;

		}

	}

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