[PATCH 6/6] drbd: Allow online change of al-stripes and al-stripe-size

From: Philipp Reisner
Date: Tue Jun 25 2013 - 10:51:14 EST

Allow to change the AL layout with an resize operation. For that
the reisze command gets two new fields: al_stripes and al_stripe_size.

In order to make the operation crash save:
1) Lock out all IO and MD-IO
2) Write the super block with MDF_PRIMARY_IND clear
3) write the bitmap to the new location (all zeros, since
we allow only while connected)
4) Initialize the new AL-area
5) Write the super block with the restored MDF_PRIMARY_IND.
6) Unfreeze all IO

Since the AL-layout has no influence on the protocol, this operation
needs to be beforemed on both sides of a resource (if intended).

Signed-off-by: Andreas Gruenbacher <agruen@xxxxxxxxxx>
Signed-off-by: Philipp Reisner <philipp.reisner@xxxxxxxxxx>
---
drivers/block/drbd/drbd_actlog.c | 21 ++++++
drivers/block/drbd/drbd_int.h | 7 +-
drivers/block/drbd/drbd_main.c | 57 ++++++++-------
drivers/block/drbd/drbd_nl.c | 137 +++++++++++++++++++++++++++++-------
drivers/block/drbd/drbd_receiver.c | 2 +-
include/linux/drbd.h | 6 +-
include/linux/drbd_genl.h | 2 +
include/linux/drbd_limits.h | 9 +++
8 files changed, 188 insertions(+), 53 deletions(-)

diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c
index 6608076..28c73ca 100644
--- a/drivers/block/drbd/drbd_actlog.c
+++ b/drivers/block/drbd/drbd_actlog.c
@@ -659,6 +659,27 @@ void drbd_al_shrink(struct drbd_conf *mdev)
wake_up(&mdev->al_wait);
}

+int drbd_initialize_al(struct drbd_conf *mdev, void *buffer)
+{
+ struct al_transaction_on_disk *al = buffer;
+ struct drbd_md *md = &mdev->ldev->md;
+ sector_t al_base = md->md_offset + md->al_offset;
+ int al_size_4k = md->al_stripes * md->al_stripe_size_4k;
+ int i;
+
+ memset(al, 0, 4096);
+ al->magic = cpu_to_be32(DRBD_AL_MAGIC);
+ al->transaction_type = cpu_to_be16(AL_TR_INITIALIZED);
+ al->crc32c = cpu_to_be32(crc32c(0, al, 4096));
+
+ for (i = 0; i < al_size_4k; i++) {
+ int err = drbd_md_sync_page_io(mdev, mdev->ldev, al_base + i * 8, WRITE);
+ if (err)
+ return err;
+ }
+ return 0;
+}
+
static int w_update_odbm(struct drbd_work *w, int unused)
{
struct update_odbm_work *udw = container_of(w, struct update_odbm_work, w);
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 4519d63..2d7f608 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1133,6 +1133,7 @@ extern void drbd_mdev_cleanup(struct drbd_conf *mdev);
void drbd_print_uuids(struct drbd_conf *mdev, const char *text);

extern void conn_md_sync(struct drbd_tconn *tconn);
+extern void drbd_md_write(struct drbd_conf *mdev, void *buffer);
extern void drbd_md_sync(struct drbd_conf *mdev);
extern int drbd_md_read(struct drbd_conf *mdev, struct drbd_backing_dev *bdev);
extern void drbd_uuid_set(struct drbd_conf *mdev, int idx, u64 val) __must_hold(local);
@@ -1468,12 +1469,15 @@ extern void drbd_resume_io(struct drbd_conf *mdev);
extern char *ppsize(char *buf, unsigned long long size);
extern sector_t drbd_new_dev_size(struct drbd_conf *, struct drbd_backing_dev *, sector_t, int);
enum determine_dev_size {
+ DS_ERROR_SHRINK = -3,
+ DS_ERROR_SPACE_MD = -2,
DS_ERROR = -1,
DS_UNCHANGED = 0,
DS_SHRUNK = 1,
DS_GREW = 2
};
-extern enum determine_dev_size drbd_determine_dev_size(struct drbd_conf *, enum dds_flags) __must_hold(local);
+extern enum determine_dev_size
+drbd_determine_dev_size(struct drbd_conf *, enum dds_flags, struct resize_parms *) __must_hold(local);
extern void resync_after_online_grow(struct drbd_conf *);
extern void drbd_reconsider_max_bio_size(struct drbd_conf *mdev);
extern enum drbd_state_rv drbd_set_role(struct drbd_conf *mdev,
@@ -1639,6 +1643,7 @@ extern int __drbd_set_out_of_sync(struct drbd_conf *mdev, sector_t sector,
#define drbd_set_out_of_sync(mdev, sector, size) \
__drbd_set_out_of_sync(mdev, sector, size, __FILE__, __LINE__)
extern void drbd_al_shrink(struct drbd_conf *mdev);
+extern int drbd_initialize_al(struct drbd_conf *, void *);

/* drbd_nl.c */
/* state info broadcast */
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 49040a3..55635ed 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2879,34 +2879,14 @@ struct meta_data_on_disk {
u8 reserved_u8[4096 - (7*8 + 10*4)];
} __packed;

-/**
- * drbd_md_sync() - Writes the meta data super block if the MD_DIRTY flag bit is set
- * @mdev: DRBD device.
- */
-void drbd_md_sync(struct drbd_conf *mdev)
+
+
+void drbd_md_write(struct drbd_conf *mdev, void *b)
{
- struct meta_data_on_disk *buffer;
+ struct meta_data_on_disk *buffer = b;
sector_t sector;
int i;

- /* Don't accidentally change the DRBD meta data layout. */
- BUILD_BUG_ON(UI_SIZE != 4);
- BUILD_BUG_ON(sizeof(struct meta_data_on_disk) != 4096);
-
- del_timer(&mdev->md_sync_timer);
- /* timer may be rearmed by drbd_md_mark_dirty() now. */
- if (!test_and_clear_bit(MD_DIRTY, &mdev->flags))
- return;
-
- /* We use here D_FAILED and not D_ATTACHING because we try to write
- * metadata even if we detach due to a disk failure! */
- if (!get_ldev_if_state(mdev, D_FAILED))
- return;
-
- buffer = drbd_md_get_buffer(mdev);
- if (!buffer)
- goto out;
-
memset(buffer, 0, sizeof(*buffer));

buffer->la_size_sect = cpu_to_be64(drbd_get_capacity(mdev->this_bdev));
@@ -2935,6 +2915,35 @@ void drbd_md_sync(struct drbd_conf *mdev)
dev_err(DEV, "meta data update failed!\n");
drbd_chk_io_error(mdev, 1, DRBD_META_IO_ERROR);
}
+}
+
+/**
+ * drbd_md_sync() - Writes the meta data super block if the MD_DIRTY flag bit is set
+ * @mdev: DRBD device.
+ */
+void drbd_md_sync(struct drbd_conf *mdev)
+{
+ struct meta_data_on_disk *buffer;
+
+ /* Don't accidentally change the DRBD meta data layout. */
+ BUILD_BUG_ON(UI_SIZE != 4);
+ BUILD_BUG_ON(sizeof(struct meta_data_on_disk) != 4096);
+
+ del_timer(&mdev->md_sync_timer);
+ /* timer may be rearmed by drbd_md_mark_dirty() now. */
+ if (!test_and_clear_bit(MD_DIRTY, &mdev->flags))
+ return;
+
+ /* We use here D_FAILED and not D_ATTACHING because we try to write
+ * metadata even if we detach due to a disk failure! */
+ if (!get_ldev_if_state(mdev, D_FAILED))
+ return;
+
+ buffer = drbd_md_get_buffer(mdev);
+ if (!buffer)
+ goto out;
+
+ drbd_md_write(mdev, buffer);

/* Update mdev->ldev->md.la_size_sect,
* since we updated it on metadata. */
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 45d1275..8cc1e64 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -827,12 +827,17 @@ void drbd_resume_io(struct drbd_conf *mdev)
* Returns 0 on success, negative return values indicate errors.
* You should call drbd_md_sync() after calling this function.
*/
-enum determine_dev_size drbd_determine_dev_size(struct drbd_conf *mdev, enum dds_flags flags) __must_hold(local)
+enum determine_dev_size
+drbd_determine_dev_size(struct drbd_conf *mdev, enum dds_flags flags, struct resize_parms *rs) __must_hold(local)
{
sector_t prev_first_sect, prev_size; /* previous meta location */
sector_t la_size_sect, u_size;
+ struct drbd_md *md = &mdev->ldev->md;
+ u32 prev_al_stripe_size_4k;
+ u32 prev_al_stripes;
sector_t size;
char ppb[10];
+ void *buffer;

int md_moved, la_size_changed;
enum determine_dev_size rv = DS_UNCHANGED;
@@ -847,6 +852,11 @@ enum determine_dev_size drbd_determine_dev_size(struct drbd_conf *mdev, enum dds
* still lock the act_log to not trigger ASSERTs there.
*/
drbd_suspend_io(mdev);
+ buffer = drbd_md_get_buffer(mdev); /* Lock meta-data IO */
+ if (!buffer) {
+ drbd_resume_io(mdev);
+ return DS_ERROR;
+ }

/* no wait necessary anymore, actually we could assert that */
wait_event(mdev->al_wait, lc_try_lock(mdev->act_log));
@@ -855,7 +865,17 @@ enum determine_dev_size drbd_determine_dev_size(struct drbd_conf *mdev, enum dds
prev_size = mdev->ldev->md.md_size_sect;
la_size_sect = mdev->ldev->md.la_size_sect;

- /* TODO: should only be some assert here, not (re)init... */
+ if (rs) {
+ /* rs is non NULL if we should change the AL layout only */
+
+ prev_al_stripes = md->al_stripes;
+ prev_al_stripe_size_4k = md->al_stripe_size_4k;
+
+ md->al_stripes = rs->al_stripes;
+ md->al_stripe_size_4k = rs->al_stripe_size / 4;
+ md->al_size_4k = (u64)rs->al_stripes * rs->al_stripe_size / 4;
+ }
+
drbd_md_set_sector_offsets(mdev, mdev->ldev);

rcu_read_lock();
@@ -863,6 +883,21 @@ enum determine_dev_size drbd_determine_dev_size(struct drbd_conf *mdev, enum dds
rcu_read_unlock();
size = drbd_new_dev_size(mdev, mdev->ldev, u_size, flags & DDSF_FORCED);

+ if (size < la_size_sect) {
+ if (rs && u_size == 0) {
+ /* Remove "rs &&" later. This check should always be active, but
+ right now the receiver expects the permissive behavior */
+ dev_warn(DEV, "Implicit shrink not allowed. "
+ "Use --size=%llus for explicit shrink.\n",
+ (unsigned long long)size);
+ rv = DS_ERROR_SHRINK;
+ }
+ if (u_size > size)
+ rv = DS_ERROR_SPACE_MD;
+ if (rv != DS_UNCHANGED)
+ goto err_out;
+ }
+
if (drbd_get_capacity(mdev->this_bdev) != size ||
drbd_bm_capacity(mdev) != size) {
int err;
@@ -886,38 +921,57 @@ enum determine_dev_size drbd_determine_dev_size(struct drbd_conf *mdev, enum dds
dev_info(DEV, "size = %s (%llu KB)\n", ppsize(ppb, size>>1),
(unsigned long long)size>>1);
}
- if (rv == DS_ERROR)
- goto out;
+ if (rv <= DS_ERROR)
+ goto err_out;

la_size_changed = (la_size_sect != mdev->ldev->md.la_size_sect);

md_moved = prev_first_sect != drbd_md_first_sector(mdev->ldev)
|| prev_size != mdev->ldev->md.md_size_sect;

- if (la_size_changed || md_moved) {
- int err;
+ if (la_size_changed || md_moved || rs) {
+ u32 prev_flags;

drbd_al_shrink(mdev); /* All extents inactive. */
+
+ prev_flags = md->flags;
+ md->flags &= ~MDF_PRIMARY_IND;
+ drbd_md_write(mdev, buffer);
+
dev_info(DEV, "Writing the whole bitmap, %s\n",
la_size_changed && md_moved ? "size changed and md moved" :
la_size_changed ? "size changed" : "md moved");
/* next line implicitly does drbd_suspend_io()+drbd_resume_io() */
- err = drbd_bitmap_io(mdev, md_moved ? &drbd_bm_write_all : &drbd_bm_write,
- "size changed", BM_LOCKED_MASK);
- if (err) {
- rv = DS_ERROR;
- goto out;
- }
- drbd_md_mark_dirty(mdev);
+ drbd_bitmap_io(mdev, md_moved ? &drbd_bm_write_all : &drbd_bm_write,
+ "size changed", BM_LOCKED_MASK);
+ drbd_initialize_al(mdev, buffer);
+
+ md->flags = prev_flags;
+ drbd_md_write(mdev, buffer);
+
+ if (rs)
+ dev_info(DEV, "Changed AL layout to al-stripes = %d, al-stripe-size-kB = %d\n",
+ md->al_stripes, md->al_stripe_size_4k * 4);
}

if (size > la_size_sect)
rv = DS_GREW;
if (size < la_size_sect)
rv = DS_SHRUNK;
-out:
+
+ if (0) {
+ err_out:
+ if (rs) {
+ md->al_stripes = prev_al_stripes;
+ md->al_stripe_size_4k = prev_al_stripe_size_4k;
+ md->al_size_4k = (u64)prev_al_stripes * prev_al_stripe_size_4k;
+
+ drbd_md_set_sector_offsets(mdev, mdev->ldev);
+ }
+ }
lc_unlock(mdev->act_log);
wake_up(&mdev->al_wait);
+ drbd_md_put_buffer(mdev);
drbd_resume_io(mdev);

return rv;
@@ -1618,8 +1672,8 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info)
!drbd_md_test_flag(mdev->ldev, MDF_CONNECTED_IND))
set_bit(USE_DEGR_WFC_T, &mdev->flags);

- dd = drbd_determine_dev_size(mdev, 0);
- if (dd == DS_ERROR) {
+ dd = drbd_determine_dev_size(mdev, 0, NULL);
+ if (dd <= DS_ERROR) {
retcode = ERR_NOMEM_BITMAP;
goto force_diskless_dec;
} else if (dd == DS_GREW)
@@ -2316,6 +2370,7 @@ int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
struct drbd_conf *mdev;
enum drbd_ret_code retcode;
enum determine_dev_size dd;
+ bool change_al_layout = false;
enum dds_flags ddsf;
sector_t u_size;
int err;
@@ -2326,31 +2381,33 @@ int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
if (retcode != NO_ERROR)
goto fail;

+ mdev = adm_ctx.mdev;
+ if (!get_ldev(mdev)) {
+ retcode = ERR_NO_DISK;
+ goto fail;
+ }
+
memset(&rs, 0, sizeof(struct resize_parms));
+ rs.al_stripes = mdev->ldev->md.al_stripes;
+ rs.al_stripe_size = mdev->ldev->md.al_stripe_size_4k * 4;
if (info->attrs[DRBD_NLA_RESIZE_PARMS]) {
err = resize_parms_from_attrs(&rs, info);
if (err) {
retcode = ERR_MANDATORY_TAG;
drbd_msg_put_info(from_attrs_err_to_txt(err));
- goto fail;
+ goto fail_ldev;
}
}

- mdev = adm_ctx.mdev;
if (mdev->state.conn > C_CONNECTED) {
retcode = ERR_RESIZE_RESYNC;
- goto fail;
+ goto fail_ldev;
}

if (mdev->state.role == R_SECONDARY &&
mdev->state.peer == R_SECONDARY) {
retcode = ERR_NO_PRIMARY;
- goto fail;
- }
-
- if (!get_ldev(mdev)) {
- retcode = ERR_NO_DISK;
- goto fail;
+ goto fail_ldev;
}

if (rs.no_resync && mdev->tconn->agreed_pro_version < 93) {
@@ -2369,6 +2426,28 @@ int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
}
}

+ if (mdev->ldev->md.al_stripes != rs.al_stripes ||
+ mdev->ldev->md.al_stripe_size_4k != rs.al_stripe_size / 4) {
+ u32 al_size_k = rs.al_stripes * rs.al_stripe_size;
+
+ if (al_size_k > (16 * 1024 * 1024)) {
+ retcode = ERR_MD_LAYOUT_TOO_BIG;
+ goto fail_ldev;
+ }
+
+ if (al_size_k < MD_32kB_SECT/2) {
+ retcode = ERR_MD_LAYOUT_TOO_SMALL;
+ goto fail_ldev;
+ }
+
+ if (mdev->state.conn != C_CONNECTED) {
+ retcode = ERR_MD_LAYOUT_CONNECTED;
+ goto fail_ldev;
+ }
+
+ change_al_layout = true;
+ }
+
if (mdev->ldev->known_size != drbd_get_capacity(mdev->ldev->backing_bdev))
mdev->ldev->known_size = drbd_get_capacity(mdev->ldev->backing_bdev);

@@ -2384,12 +2463,18 @@ int drbd_adm_resize(struct sk_buff *skb, struct genl_info *info)
}

ddsf = (rs.resize_force ? DDSF_FORCED : 0) | (rs.no_resync ? DDSF_NO_RESYNC : 0);
- dd = drbd_determine_dev_size(mdev, ddsf);
+ dd = drbd_determine_dev_size(mdev, ddsf, change_al_layout ? &rs : NULL);
drbd_md_sync(mdev);
put_ldev(mdev);
if (dd == DS_ERROR) {
retcode = ERR_NOMEM_BITMAP;
goto fail;
+ } else if (dd == DS_ERROR_SPACE_MD) {
+ retcode = ERR_MD_LAYOUT_NO_FIT;
+ goto fail;
+ } else if (dd == DS_ERROR_SHRINK) {
+ retcode = ERR_IMPLICIT_SHRINK;
+ goto fail;
}

if (mdev->state.conn == C_CONNECTED) {
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 26852b8..cc29cd3 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -3617,7 +3617,7 @@ static int receive_sizes(struct drbd_tconn *tconn, struct packet_info *pi)

ddsf = be16_to_cpu(p->dds_flags);
if (get_ldev(mdev)) {
- dd = drbd_determine_dev_size(mdev, ddsf);
+ dd = drbd_determine_dev_size(mdev, ddsf, NULL);
put_ldev(mdev);
if (dd == DS_ERROR)
return -EIO;
diff --git a/include/linux/drbd.h b/include/linux/drbd.h
index 1b4d4ee..de7d74a 100644
--- a/include/linux/drbd.h
+++ b/include/linux/drbd.h
@@ -177,7 +177,11 @@ enum drbd_ret_code {
ERR_NEED_APV_100 = 163,
ERR_NEED_ALLOW_TWO_PRI = 164,
ERR_MD_UNCLEAN = 165,
-
+ ERR_MD_LAYOUT_CONNECTED = 166,
+ ERR_MD_LAYOUT_TOO_BIG = 167,
+ ERR_MD_LAYOUT_TOO_SMALL = 168,
+ ERR_MD_LAYOUT_NO_FIT = 169,
+ ERR_IMPLICIT_SHRINK = 170,
/* insert new ones above this line */
AFTER_LAST_ERR_CODE
};
diff --git a/include/linux/drbd_genl.h b/include/linux/drbd_genl.h
index d0d8fac..e8c4457 100644
--- a/include/linux/drbd_genl.h
+++ b/include/linux/drbd_genl.h
@@ -181,6 +181,8 @@ GENL_struct(DRBD_NLA_RESIZE_PARMS, 7, resize_parms,
__u64_field(1, DRBD_GENLA_F_MANDATORY, resize_size)
__flg_field(2, DRBD_GENLA_F_MANDATORY, resize_force)
__flg_field(3, DRBD_GENLA_F_MANDATORY, no_resync)
+ __u32_field_def(4, 0 /* OPTIONAL */, al_stripes, DRBD_AL_STRIPES_DEF)
+ __u32_field_def(5, 0 /* OPTIONAL */, al_stripe_size, DRBD_AL_STRIPE_SIZE_DEF)
)

GENL_struct(DRBD_NLA_STATE_INFO, 8, state_info,
diff --git a/include/linux/drbd_limits.h b/include/linux/drbd_limits.h
index 1fedf2b..17e50bb 100644
--- a/include/linux/drbd_limits.h
+++ b/include/linux/drbd_limits.h
@@ -215,4 +215,13 @@
#define DRBD_ALWAYS_ASBP_DEF 0
#define DRBD_USE_RLE_DEF 1

+#define DRBD_AL_STRIPES_MIN 1
+#define DRBD_AL_STRIPES_MAX 1024
+#define DRBD_AL_STRIPES_DEF 1
+#define DRBD_AL_STRIPES_SCALE '1'
+
+#define DRBD_AL_STRIPE_SIZE_MIN 4
+#define DRBD_AL_STRIPE_SIZE_MAX 16777216
+#define DRBD_AL_STRIPE_SIZE_DEF 32
+#define DRBD_AL_STRIPE_SIZE_SCALE 'k' /* kilobytes */
#endif
--
1.7.9.5

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