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authorChris Mason <chris.mason@oracle.com>2008-06-12 14:46:17 -0400
committerChris Mason <chris.mason@oracle.com>2008-09-25 11:04:03 -0400
commit1cc127b5d1b71453091859301de4a7dd6ee96fa8 (patch)
treecb1280305a04eb5e6838f91781e668e3bdeed208
parentdf5b5520b21d8a2554ede65c09b288833c77144d (diff)
Btrfs: Add a thread pool just for submit_bio
If a bio submission is after a lock holder waiting for the bio on the work queue, it is possible to deadlock. Move the bios into their own pool. Signed-off-by: Chris Mason <chris.mason@oracle.com>
-rw-r--r--fs/btrfs/ctree.h4
-rw-r--r--fs/btrfs/disk-io.c4
-rw-r--r--fs/btrfs/volumes.c3
3 files changed, 10 insertions, 1 deletions
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 181c81d2989..dcea9d706d9 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -529,9 +529,13 @@ struct btrfs_fs_info {
* can run with FS locks held, and the writers may be waiting for
* those locks. We don't want ordering in the pending list to cause
* deadlocks, and so the two are serviced separately.
+ *
+ * A third pool does submit_bio to avoid deadlocking with the other
+ * two
*/
struct btrfs_workers workers;
struct btrfs_workers endio_workers;
+ struct btrfs_workers submit_workers;
int thread_pool_size;
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index c6a710a668c..e5c758e306d 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1233,8 +1233,10 @@ struct btrfs_root *open_ctree(struct super_block *sb,
* cannot dynamically grow.
*/
btrfs_init_workers(&fs_info->workers, fs_info->thread_pool_size);
+ btrfs_init_workers(&fs_info->submit_workers, fs_info->thread_pool_size);
btrfs_init_workers(&fs_info->endio_workers, fs_info->thread_pool_size);
btrfs_start_workers(&fs_info->workers, 1);
+ btrfs_start_workers(&fs_info->submit_workers, 1);
btrfs_start_workers(&fs_info->endio_workers, fs_info->thread_pool_size);
@@ -1343,6 +1345,7 @@ fail_sb_buffer:
extent_io_tree_empty_lru(&BTRFS_I(fs_info->btree_inode)->io_tree);
btrfs_stop_workers(&fs_info->workers);
btrfs_stop_workers(&fs_info->endio_workers);
+ btrfs_stop_workers(&fs_info->submit_workers);
fail_iput:
iput(fs_info->btree_inode);
fail:
@@ -1597,6 +1600,7 @@ int close_ctree(struct btrfs_root *root)
btrfs_stop_workers(&fs_info->workers);
btrfs_stop_workers(&fs_info->endio_workers);
+ btrfs_stop_workers(&fs_info->submit_workers);
iput(fs_info->btree_inode);
#if 0
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index c57458ce633..ba396857102 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2112,7 +2112,8 @@ int schedule_bio(struct btrfs_root *root, struct btrfs_device *device,
spin_unlock(&device->io_lock);
if (should_queue)
- btrfs_queue_worker(&root->fs_info->workers, &device->work);
+ btrfs_queue_worker(&root->fs_info->submit_workers,
+ &device->work);
return 0;
}