===================================================================
@@ -1183,6 +1183,10 @@ static struct mapped_device *alloc_dev(i
if (!md->wq)
goto bad_thread;
+ md->bdev = bdget_disk(md->disk, 0);
+ if (!md->bdev)
+ goto bad_bdev;
+
/* Populate the mapping, nobody knows we exist yet */
spin_lock(&_minor_lock);
old_md = idr_replace(&_minor_idr, md, minor);
@@ -1192,6 +1196,8 @@ static struct mapped_device *alloc_dev(i
return md;
+bad_bdev:
+ destroy_workqueue(md->wq);
bad_thread:
put_disk(md->disk);
bad_disk:
@@ -1217,10 +1223,8 @@ static void free_dev(struct mapped_devic
{
int minor = MINOR(disk_devt(md->disk));
- if (md->bdev) {
- unlock_fs(md);
- bdput(md->bdev);
- }
+ unlock_fs(md);
+ bdput(md->bdev);
destroy_workqueue(md->wq);
mempool_destroy(md->tio_pool);
mempool_destroy(md->io_pool);
@@ -1280,8 +1284,7 @@ static int __bind(struct mapped_device *
if (size != get_capacity(md->disk))
memset(&md->geometry, 0, sizeof(md->geometry));
- if (md->bdev)
- __set_size(md, size);
+ __set_size(md, size);
if (!size) {
dm_table_destroy(t);
@@ -1523,11 +1526,6 @@ int dm_swap_table(struct mapped_device *
if (!dm_suspended(md))
goto out;
- /* without bdev, the device size cannot be changed */
- if (!md->bdev)
- if (get_capacity(md->disk) != dm_table_get_size(table))
- goto out;
-
__unbind(md);
r = __bind(md, table);
@@ -1606,13 +1604,6 @@ int dm_suspend(struct mapped_device *md,
/* bdget() can stall if the pending I/Os are not flushed */
if (!noflush) {
- md->bdev = bdget_disk(md->disk, 0);
- if (!md->bdev) {
- DMWARN("bdget failed in dm_suspend");
- r = -ENOMEM;
- goto out;
- }
-
/*
* Flush I/O to the device. noflush supersedes do_lockfs,
* because lock_fs() needs to flush I/Os.
@@ -1678,11 +1669,6 @@ int dm_suspend(struct mapped_device *md,
set_bit(DMF_SUSPENDED, &md->flags);
out:
- if (r && md->bdev) {
- bdput(md->bdev);
- md->bdev = NULL;
- }
-
dm_table_put(map);
out_unlock:
@@ -1711,11 +1697,6 @@ int dm_resume(struct mapped_device *md)
unlock_fs(md);
- if (md->bdev) {
- bdput(md->bdev);
- md->bdev = NULL;
- }
-
clear_bit(DMF_SUSPENDED, &md->flags);
dm_table_unplug_all(map);
Always keep the reference to structure block_device. Reference to block_device is obtained with function bdget_disk (and is released with bdput. bdget_disk was called while the device was being suspended, in dm_suspend() --- however at this point, there could be another devices already suspended. bdget_disk can wait for IO and allocate memory and this could result in waiting for already suspended device, resulting in deadlock. It caused bug https://bugzilla.redhat.com/show_bug.cgi?id=179786 This patch changes the code so that it gets the reference to struct block_device when struct mapped_device is allocated and initialized in (alloc_dev) and drops the reference when it is destroyed in free_dev. Thus, there is no call to bdget_disk, while any device is suspended. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> --- drivers/md/dm.c | 37 +++++++++---------------------------- 1 file changed, 9 insertions(+), 28 deletions(-) -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel