qubes-linux-kernel/patches.fixes/dm-table-switch-to-readonly
2010-07-07 13:12:45 +02:00

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From: Hannes Reinecke <hare@suse.de>
Subject: dm multipath devices are not getting created for readonly devices
References: bnc#382705
Patch-mainline: not yet
Currently we cannot create device-mapper tables for multipath devices
whenever they are read-only.
This patch modifies the device-mapper to set the 'READ-ONLY' flag
automatically whenever a read-only is added to the table.
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
drivers/md/dm-table.c | 10 +++++++++-
drivers/md/dm.c | 18 ++++++++++++++++--
2 files changed, 25 insertions(+), 3 deletions(-)
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -462,11 +462,19 @@ static int __table_get_device(struct dm_
dd->dm_dev.mode = mode;
dd->dm_dev.bdev = NULL;
- if ((r = open_dev(dd, dev, t->md))) {
+ r = open_dev(dd, dev, t->md);
+ if (r == -EROFS) {
+ dd->dm_dev.mode &= ~FMODE_WRITE;
+ r = open_dev(dd, dev, t->md);
+ }
+ if (r) {
kfree(dd);
return r;
}
+ if (dd->dm_dev.mode != mode)
+ t->mode = dd->dm_dev.mode;
+
format_dev_t(dd->dm_dev.name, dev);
atomic_set(&dd->count, 0);
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -337,16 +337,25 @@ int dm_deleting_md(struct mapped_device
static int dm_blk_open(struct block_device *bdev, fmode_t mode)
{
struct mapped_device *md;
+ int retval = 0;
spin_lock(&_minor_lock);
md = bdev->bd_disk->private_data;
- if (!md)
+ if (!md) {
+ retval = -ENXIO;
goto out;
+ }
if (test_bit(DMF_FREEING, &md->flags) ||
dm_deleting_md(md)) {
md = NULL;
+ retval = -ENXIO;
+ goto out;
+ }
+ if (get_disk_ro(md->disk) && (mode & FMODE_WRITE)) {
+ md = NULL;
+ retval = -EROFS;
goto out;
}
@@ -356,7 +365,7 @@ static int dm_blk_open(struct block_devi
out:
spin_unlock(&_minor_lock);
- return md ? 0 : -ENXIO;
+ return retval;
}
static int dm_blk_close(struct gendisk *disk, fmode_t mode)
@@ -2093,6 +2102,11 @@ static struct dm_table *__bind(struct ma
old_map = md->map;
md->map = t;
dm_table_set_restrictions(t, q, limits);
+ if (!(dm_table_get_mode(t) & FMODE_WRITE)) {
+ set_disk_ro(md->disk, 1);
+ } else {
+ set_disk_ro(md->disk, 0);
+ }
write_unlock_irqrestore(&md->map_lock, flags);
return old_map;