From 3754d8561b039b0ef2dacb5bd78d569ce8a4a593 Mon Sep 17 00:00:00 2001 From: Alasdair G Kergon Date: Tue, 9 Aug 2011 10:49:59 +1000 Subject: [PATCH] Add a target feature flag to indicate that a target does not work in read-only mode. The thin provisioning target uses this. Signed-off-by: Alasdair G Kergon --- drivers/md/dm-table.c | 6 ++++++ include/linux/device-mapper.h | 4 ++++ 2 files changed, 10 insertions(+) diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 1ecb471438fc..61d3e8395e63 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -774,6 +774,12 @@ int dm_table_add_target(struct dm_table *t, const char *type, t->singleton = 1; } + if (dm_target_always_writeable(tgt->type) && !(t->mode & FMODE_WRITE)) { + DMERR("%s: target type %s may not be included in read-only tables", + dm_device_name(t->md), type); + return -EINVAL; + } + tgt->table = t; tgt->begin = start; tgt->len = len; diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index e85bb3bf503d..ba99936e8d5f 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -166,6 +166,10 @@ struct target_type { #define DM_TARGET_SINGLETON 0x00000001 #define dm_target_needs_singleton(type) ((type)->features & DM_TARGET_SINGLETON) +#define DM_TARGET_ALWAYS_WRITEABLE 0x00000002 +#define dm_target_always_writeable(type) \ + ((type)->features & DM_TARGET_ALWAYS_WRITEABLE) + struct dm_target { struct dm_table *table; struct target_type *type; -- 2.39.5