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path: root/drivers/md/dm-thin.c
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Diffstat (limited to 'drivers/md/dm-thin.c')
-rw-r--r--drivers/md/dm-thin.c200
1 files changed, 160 insertions, 40 deletions
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 004ad1652b7..759cffc45ca 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -922,7 +922,7 @@ static int alloc_data_block(struct thin_c *tc, dm_block_t *result)
return r;
if (free_blocks <= pool->low_water_blocks && !pool->low_water_triggered) {
- DMWARN("%s: reached low water mark, sending event.",
+ DMWARN("%s: reached low water mark for data device: sending event.",
dm_device_name(pool->pool_md));
spin_lock_irqsave(&pool->lock, flags);
pool->low_water_triggered = 1;
@@ -1281,6 +1281,10 @@ static void process_bio_fail(struct thin_c *tc, struct bio *bio)
bio_io_error(bio);
}
+/*
+ * FIXME: should we also commit due to size of transaction, measured in
+ * metadata blocks?
+ */
static int need_commit_due_to_time(struct pool *pool)
{
return jiffies < pool->last_commit_jiffies ||
@@ -1909,6 +1913,56 @@ static int parse_pool_features(struct dm_arg_set *as, struct pool_features *pf,
return r;
}
+static void metadata_low_callback(void *context)
+{
+ struct pool *pool = context;
+
+ DMWARN("%s: reached low water mark for metadata device: sending event.",
+ dm_device_name(pool->pool_md));
+
+ dm_table_event(pool->ti->table);
+}
+
+static sector_t get_metadata_dev_size(struct block_device *bdev)
+{
+ sector_t metadata_dev_size = i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
+ char buffer[BDEVNAME_SIZE];
+
+ if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING) {
+ DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
+ bdevname(bdev, buffer), THIN_METADATA_MAX_SECTORS);
+ metadata_dev_size = THIN_METADATA_MAX_SECTORS_WARNING;
+ }
+
+ return metadata_dev_size;
+}
+
+static dm_block_t get_metadata_dev_size_in_blocks(struct block_device *bdev)
+{
+ sector_t metadata_dev_size = get_metadata_dev_size(bdev);
+
+ sector_div(metadata_dev_size, THIN_METADATA_BLOCK_SIZE >> SECTOR_SHIFT);
+
+ return metadata_dev_size;
+}
+
+/*
+ * When a metadata threshold is crossed a dm event is triggered, and
+ * userland should respond by growing the metadata device. We could let
+ * userland set the threshold, like we do with the data threshold, but I'm
+ * not sure they know enough to do this well.
+ */
+static dm_block_t calc_metadata_threshold(struct pool_c *pt)
+{
+ /*
+ * 4M is ample for all ops with the possible exception of thin
+ * device deletion which is harmless if it fails (just retry the
+ * delete after you've grown the device).
+ */
+ dm_block_t quarter = get_metadata_dev_size_in_blocks(pt->metadata_dev->bdev) / 4;
+ return min((dm_block_t)1024ULL /* 4M */, quarter);
+}
+
/*
* thin-pool <metadata dev> <data dev>
* <data block size (sectors)>
@@ -1931,8 +1985,7 @@ static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
unsigned long block_size;
dm_block_t low_water_blocks;
struct dm_dev *metadata_dev;
- sector_t metadata_dev_size;
- char b[BDEVNAME_SIZE];
+ fmode_t metadata_mode;
/*
* FIXME Remove validation from scope of lock.
@@ -1944,19 +1997,32 @@ static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
r = -EINVAL;
goto out_unlock;
}
+
as.argc = argc;
as.argv = argv;
- r = dm_get_device(ti, argv[0], FMODE_READ | FMODE_WRITE, &metadata_dev);
+ /*
+ * Set default pool features.
+ */
+ pool_features_init(&pf);
+
+ dm_consume_args(&as, 4);
+ r = parse_pool_features(&as, &pf, ti);
+ if (r)
+ goto out_unlock;
+
+ metadata_mode = FMODE_READ | ((pf.mode == PM_READ_ONLY) ? 0 : FMODE_WRITE);
+ r = dm_get_device(ti, argv[0], metadata_mode, &metadata_dev);
if (r) {
ti->error = "Error opening metadata block device";
goto out_unlock;
}
- metadata_dev_size = i_size_read(metadata_dev->bdev->bd_inode) >> SECTOR_SHIFT;
- if (metadata_dev_size > THIN_METADATA_MAX_SECTORS_WARNING)
- DMWARN("Metadata device %s is larger than %u sectors: excess space will not be used.",
- bdevname(metadata_dev->bdev, b), THIN_METADATA_MAX_SECTORS);
+ /*
+ * Run for the side-effect of possibly issuing a warning if the
+ * device is too big.
+ */
+ (void) get_metadata_dev_size(metadata_dev->bdev);
r = dm_get_device(ti, argv[1], FMODE_READ | FMODE_WRITE, &data_dev);
if (r) {
@@ -1979,16 +2045,6 @@ static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
goto out;
}
- /*
- * Set default pool features.
- */
- pool_features_init(&pf);
-
- dm_consume_args(&as, 4);
- r = parse_pool_features(&as, &pf, ti);
- if (r)
- goto out;
-
pt = kzalloc(sizeof(*pt), GFP_KERNEL);
if (!pt) {
r = -ENOMEM;
@@ -2040,6 +2096,13 @@ static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
}
ti->private = pt;
+ r = dm_pool_register_metadata_threshold(pt->pool->pmd,
+ calc_metadata_threshold(pt),
+ metadata_low_callback,
+ pool);
+ if (r)
+ goto out_free_pt;
+
pt->callbacks.congested_fn = pool_is_congested;
dm_table_add_target_callbacks(ti->table, &pt->callbacks);
@@ -2079,18 +2142,7 @@ static int pool_map(struct dm_target *ti, struct bio *bio)
return r;
}
-/*
- * Retrieves the number of blocks of the data device from
- * the superblock and compares it to the actual device size,
- * thus resizing the data device in case it has grown.
- *
- * This both copes with opening preallocated data devices in the ctr
- * being followed by a resume
- * -and-
- * calling the resume method individually after userspace has
- * grown the data device in reaction to a table event.
- */
-static int pool_preresume(struct dm_target *ti)
+static int maybe_resize_data_dev(struct dm_target *ti, bool *need_commit)
{
int r;
struct pool_c *pt = ti->private;
@@ -2098,12 +2150,7 @@ static int pool_preresume(struct dm_target *ti)
sector_t data_size = ti->len;
dm_block_t sb_data_size;
- /*
- * Take control of the pool object.
- */
- r = bind_control_target(pool, ti);
- if (r)
- return r;
+ *need_commit = false;
(void) sector_div(data_size, pool->sectors_per_block);
@@ -2114,7 +2161,7 @@ static int pool_preresume(struct dm_target *ti)
}
if (data_size < sb_data_size) {
- DMERR("pool target too small, is %llu blocks (expected %llu)",
+ DMERR("pool target (%llu blocks) too small: expected %llu",
(unsigned long long)data_size, sb_data_size);
return -EINVAL;
@@ -2122,17 +2169,90 @@ static int pool_preresume(struct dm_target *ti)
r = dm_pool_resize_data_dev(pool->pmd, data_size);
if (r) {
DMERR("failed to resize data device");
- /* FIXME Stricter than necessary: Rollback transaction instead here */
set_pool_mode(pool, PM_READ_ONLY);
return r;
}
- (void) commit_or_fallback(pool);
+ *need_commit = true;
}
return 0;
}
+static int maybe_resize_metadata_dev(struct dm_target *ti, bool *need_commit)
+{
+ int r;
+ struct pool_c *pt = ti->private;
+ struct pool *pool = pt->pool;
+ dm_block_t metadata_dev_size, sb_metadata_dev_size;
+
+ *need_commit = false;
+
+ metadata_dev_size = get_metadata_dev_size(pool->md_dev);
+
+ r = dm_pool_get_metadata_dev_size(pool->pmd, &sb_metadata_dev_size);
+ if (r) {
+ DMERR("failed to retrieve data device size");
+ return r;
+ }
+
+ if (metadata_dev_size < sb_metadata_dev_size) {
+ DMERR("metadata device (%llu sectors) too small: expected %llu",
+ metadata_dev_size, sb_metadata_dev_size);
+ return -EINVAL;
+
+ } else if (metadata_dev_size > sb_metadata_dev_size) {
+ r = dm_pool_resize_metadata_dev(pool->pmd, metadata_dev_size);
+ if (r) {
+ DMERR("failed to resize metadata device");
+ return r;
+ }
+
+ *need_commit = true;
+ }
+
+ return 0;
+}
+
+/*
+ * Retrieves the number of blocks of the data device from
+ * the superblock and compares it to the actual device size,
+ * thus resizing the data device in case it has grown.
+ *
+ * This both copes with opening preallocated data devices in the ctr
+ * being followed by a resume
+ * -and-
+ * calling the resume method individually after userspace has
+ * grown the data device in reaction to a table event.
+ */
+static int pool_preresume(struct dm_target *ti)
+{
+ int r;
+ bool need_commit1, need_commit2;
+ struct pool_c *pt = ti->private;
+ struct pool *pool = pt->pool;
+
+ /*
+ * Take control of the pool object.
+ */
+ r = bind_control_target(pool, ti);
+ if (r)
+ return r;
+
+ r = maybe_resize_data_dev(ti, &need_commit1);
+ if (r)
+ return r;
+
+ r = maybe_resize_metadata_dev(ti, &need_commit2);
+ if (r)
+ return r;
+
+ if (need_commit1 || need_commit2)
+ (void) commit_or_fallback(pool);
+
+ return 0;
+}
+
static void pool_resume(struct dm_target *ti)
{
struct pool_c *pt = ti->private;
@@ -2549,7 +2669,7 @@ static struct target_type pool_target = {
.name = "thin-pool",
.features = DM_TARGET_SINGLETON | DM_TARGET_ALWAYS_WRITEABLE |
DM_TARGET_IMMUTABLE,
- .version = {1, 7, 0},
+ .version = {1, 8, 0},
.module = THIS_MODULE,
.ctr = pool_ctr,
.dtr = pool_dtr,