[X,2/6] md: add feature flag MD_FEATURE_RAID0_LAYOUT
diff mbox series

Message ID 20200115091428.32502-3-stefan.bader@canonical.com
State New
Headers show
Series
  • (Re)apply RAID0 layout support
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Commit Message

Stefan Bader Jan. 15, 2020, 9:14 a.m. UTC
From: NeilBrown <neilb@suse.de>

BugLink: https://bugs.launchpad.net/bugs/1850540

Due to a bug introduced in Linux 3.14 we cannot determine the
correctly layout for a multi-zone RAID0 array - there are two
possibilities.

It is possible to tell the kernel which to chose using a module
parameter, but this can be clumsy to use.  It would be best if
the choice were recorded in the metadata.
So add a feature flag for this purpose.
If it is set, then the 'layout' field of the superblock is used
to determine which layout to use.

If this flag is not set, then mddev->layout gets set to -1,
which causes the module parameter to be required.

Acked-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Song Liu <songliubraving@fb.com>
(cherry picked from commit 33f2c35a54dfd75ad0e7e86918dcbe4de799a56c)

Signed-off-by: dann frazier <dann.frazier@canonical.com>
(backported from bionic/18.04 submisstion into xenial/16.04)
[smb: contextual adjustments]
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
---
 drivers/md/md.c                | 13 +++++++++++++
 drivers/md/raid0.c             |  3 +++
 include/uapi/linux/raid/md_p.h |  2 ++
 3 files changed, 18 insertions(+)

Patch
diff mbox series

diff --git a/drivers/md/md.c b/drivers/md/md.c
index c7a006e102de..d7eae9bc76bc 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1091,6 +1091,8 @@  static int super_90_validate(struct mddev *mddev, struct md_rdev *rdev)
 			mddev->new_layout = mddev->layout;
 			mddev->new_chunk_sectors = mddev->chunk_sectors;
 		}
+		if (mddev->level == 0)
+			mddev->layout = -1;
 
 		if (sb->state & (1<<MD_SB_CLEAN))
 			mddev->recovery_cp = MaxSector;
@@ -1498,6 +1500,10 @@  static int super_1_load(struct md_rdev *rdev, struct md_rdev *refdev, int minor_
 	} else if (sb->bblog_offset != 0)
 		rdev->badblocks.shift = 0;
 
+	if ((le32_to_cpu(sb->feature_map) & MD_FEATURE_RAID0_LAYOUT) &&
+	    sb->level != 0)
+		return -EINVAL;
+
 	if (!refdev) {
 		ret = 1;
 	} else {
@@ -1609,6 +1615,10 @@  static int super_1_validate(struct mddev *mddev, struct md_rdev *rdev)
 			mddev->new_chunk_sectors = mddev->chunk_sectors;
 		}
 
+		if (mddev->level == 0 &&
+		    !(le32_to_cpu(sb->feature_map) & MD_FEATURE_RAID0_LAYOUT))
+			mddev->layout = -1;
+
 	} else if (mddev->pers == NULL) {
 		/* Insist of good event counter while assembling, except for
 		 * spares (which don't need an event count) */
@@ -6402,6 +6412,9 @@  static int set_array_info(struct mddev *mddev, mdu_array_info_t *info)
 	mddev->external	     = 0;
 
 	mddev->layout        = info->layout;
+	if (mddev->level == 0)
+		/* Cannot trust RAID0 layout info here */
+		mddev->layout = -1;
 	mddev->chunk_sectors = info->chunk_size >> 9;
 
 	mddev->max_disks     = MD_SB_DISKS;
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 7aa64c55f68d..0501114e5321 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -143,6 +143,9 @@  static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
 
 	if (conf->nr_strip_zones == 1) {
 		conf->layout = RAID0_ORIG_LAYOUT;
+	} else if (mddev->layout == RAID0_ORIG_LAYOUT ||
+		   mddev->layout == RAID0_ALT_MULTIZONE_LAYOUT) {
+			conf->layout = mddev->layout;
 	} else if (default_layout == RAID0_ORIG_LAYOUT ||
 		   default_layout == RAID0_ALT_MULTIZONE_LAYOUT) {
 		conf->layout = default_layout;
diff --git a/include/uapi/linux/raid/md_p.h b/include/uapi/linux/raid/md_p.h
index c3e654c6d518..ff8f66aa9923 100644
--- a/include/uapi/linux/raid/md_p.h
+++ b/include/uapi/linux/raid/md_p.h
@@ -313,6 +313,7 @@  struct mdp_superblock_1 {
 					     */
 #define MD_FEATURE_CLUSTERED		256 /* clustered MD */
 #define	MD_FEATURE_JOURNAL		512 /* support write cache */
+#define MD_FEATURE_RAID0_LAYOUT		4096 /* layout is meaningful for RAID0 */
 #define	MD_FEATURE_ALL			(MD_FEATURE_BITMAP_OFFSET	\
 					|MD_FEATURE_RECOVERY_OFFSET	\
 					|MD_FEATURE_RESHAPE_ACTIVE	\
@@ -323,6 +324,7 @@  struct mdp_superblock_1 {
 					|MD_FEATURE_RECOVERY_BITMAP	\
 					|MD_FEATURE_CLUSTERED		\
 					|MD_FEATURE_JOURNAL		\
+					|MD_FEATURE_RAID0_LAYOUT	\
 					)
 
 struct r5l_payload_header {