dm thin: cleanup and improve no space handling
Factor out_of_data_space() out of alloc_data_block(). Eliminate the use
of 'no_free_space' as a latch in alloc_data_block() -- this is no longer
needed now that we switch to read-only mode when we run out of data or
metadata space. In a later patch, the 'no_free_space' flag will be
eliminated entirely (in favor of checking metadata rather than relying
on a transient flag).
Move no metdata space handling into metdata_operation_failed(). Set
no_free_space when metadata space is exhausted too. This is useful,
because it offers consistency, for the following patch that will requeue
data IOs if no_free_space.
Also, rename no_space() to retry_bios_on_resume().
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 2346960..96ce36a 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -198,6 +198,7 @@
};
static enum pool_mode get_pool_mode(struct pool *pool);
+static void out_of_data_space(struct pool *pool);
static void metadata_operation_failed(struct pool *pool, const char *op, int r);
/*
@@ -922,16 +923,8 @@
{
int r;
dm_block_t free_blocks;
- unsigned long flags;
struct pool *pool = tc->pool;
- /*
- * Once no_free_space is set we must not allow allocation to succeed.
- * Otherwise it is difficult to explain, debug, test and support.
- */
- if (pool->no_free_space)
- return -ENOSPC;
-
if (get_pool_mode(pool) != PM_WRITE)
return -EINVAL;
@@ -958,31 +951,14 @@
return r;
}
- /*
- * If we still have no space we set a flag to avoid
- * doing all this checking and return -ENOSPC. This
- * flag serves as a latch that disallows allocations from
- * this pool until the admin takes action (e.g. resize or
- * table reload).
- */
if (!free_blocks) {
- DMWARN("%s: no free data space available.",
- dm_device_name(pool->pool_md));
- spin_lock_irqsave(&pool->lock, flags);
- pool->no_free_space = true;
- spin_unlock_irqrestore(&pool->lock, flags);
+ out_of_data_space(pool);
return -ENOSPC;
}
}
r = dm_pool_alloc_data_block(pool->pmd, result);
if (r) {
- if (r == -ENOSPC &&
- !dm_pool_get_free_metadata_block_count(pool->pmd, &free_blocks) &&
- !free_blocks)
- DMWARN("%s: no free metadata space available.",
- dm_device_name(pool->pool_md));
-
metadata_operation_failed(pool, "dm_pool_alloc_data_block", r);
return r;
}
@@ -1006,7 +982,7 @@
spin_unlock_irqrestore(&pool->lock, flags);
}
-static void no_space(struct pool *pool, struct dm_bio_prison_cell *cell)
+static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell)
{
struct bio *bio;
struct bio_list bios;
@@ -1119,7 +1095,7 @@
break;
case -ENOSPC:
- no_space(pool, cell);
+ retry_bios_on_resume(pool, cell);
break;
default:
@@ -1197,7 +1173,7 @@
break;
case -ENOSPC:
- no_space(pool, cell);
+ retry_bios_on_resume(pool, cell);
break;
default:
@@ -1446,15 +1422,42 @@
}
}
+static void set_no_free_space(struct pool *pool)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&pool->lock, flags);
+ pool->no_free_space = true;
+ spin_unlock_irqrestore(&pool->lock, flags);
+}
+
/*
* Rather than calling set_pool_mode directly, use these which describe the
* reason for mode degradation.
*/
+static void out_of_data_space(struct pool *pool)
+{
+ DMERR_LIMIT("%s: no free data space available.",
+ dm_device_name(pool->pool_md));
+ set_no_free_space(pool);
+ set_pool_mode(pool, PM_READ_ONLY);
+}
+
static void metadata_operation_failed(struct pool *pool, const char *op, int r)
{
+ dm_block_t free_blocks;
+
DMERR_LIMIT("%s: metadata operation '%s' failed: error = %d",
dm_device_name(pool->pool_md), op, r);
+ if (r == -ENOSPC &&
+ !dm_pool_get_free_metadata_block_count(pool->pmd, &free_blocks) &&
+ !free_blocks) {
+ DMERR_LIMIT("%s: no free metadata space available.",
+ dm_device_name(pool->pool_md));
+ set_no_free_space(pool);
+ }
+
set_pool_mode(pool, PM_READ_ONLY);
}