1 files changed, 59 insertions, 10 deletions

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index a6d35b0054ca..3ab80e9cd767 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -161,8 +161,10 @@ static noinline int run_scheduled_bios(struct btrfs_device *device)
         int again = 0;
         unsigned long num_run;
         unsigned long num_sync_run;
+        unsigned long batch_run = 0;
         unsigned long limit;
         unsigned long last_waited = 0;
+        int force_reg = 0;
 
         bdi = blk_get_backing_dev_info(device->bdev);
         fs_info = device->dev_root->fs_info;
@@ -176,19 +178,22 @@ static noinline int run_scheduled_bios(struct btrfs_device *device)
 
 loop:
         spin_lock(&device->io_lock);
-        num_run = 0;
 
 loop_lock:
+        num_run = 0;
 
         /* take all the bios off the list at once and process them
          * later on (without the lock held).  But, remember the
          * tail and other pointers so the bios can be properly reinserted
          * into the list if we hit congestion
          */
-        if (device->pending_sync_bios.head)
+        if (!force_reg && device->pending_sync_bios.head) {
                 pending_bios = &device->pending_sync_bios;
-        else
+                force_reg = 1;
+        } else {
                 pending_bios = &device->pending_bios;
+                force_reg = 0;
+        }
 
         pending = pending_bios->head;
         tail = pending_bios->tail;
@@ -228,10 +233,14 @@ loop_lock:
         while (pending) {
 
                 rmb();
-                if (pending_bios != &device->pending_sync_bios &&
-                    device->pending_sync_bios.head &&
-                    num_run > 16) {
-                        cond_resched();
+                /* we want to work on both lists, but do more bios on the
+                 * sync list than the regular list
+                 */
+                if ((num_run > 32 &&
+                    pending_bios != &device->pending_sync_bios &&
+                    device->pending_sync_bios.head) ||
+                   (num_run > 64 && pending_bios == &device->pending_sync_bios &&
+                    device->pending_bios.head)) {
                         spin_lock(&device->io_lock);
                         requeue_list(pending_bios, pending, tail);
                         goto loop_lock;
@@ -249,6 +258,8 @@ loop_lock:
                 BUG_ON(atomic_read(&cur->bi_cnt) == 0);
                 submit_bio(cur->bi_rw, cur);
                 num_run++;
+                batch_run++;
+
                 if (bio_sync(cur))
                         num_sync_run++;
 
@@ -265,7 +276,7 @@ loop_lock:
                  * is now congested.  Back off and let other work structs
                  * run instead
                  */
-                if (pending && bdi_write_congested(bdi) && num_run > 16 &&
+                if (pending && bdi_write_congested(bdi) && batch_run > 32 &&
                     fs_info->fs_devices->open_devices > 1) {
                         struct io_context *ioc;
 
@@ -366,6 +377,7 @@ static noinline int device_list_add(const char *path,
                 memcpy(fs_devices->fsid, disk_super->fsid, BTRFS_FSID_SIZE);
                 fs_devices->latest_devid = devid;
                 fs_devices->latest_trans = found_transid;
+                mutex_init(&fs_devices->device_list_mutex);
                 device = NULL;
         } else {
                 device = __find_device(&fs_devices->devices, devid,
@@ -392,7 +404,11 @@ static noinline int device_list_add(const char *path,
                         return -ENOMEM;
                 }
                 INIT_LIST_HEAD(&device->dev_alloc_list);
+
+                mutex_lock(&fs_devices->device_list_mutex);
                 list_add(&device->dev_list, &fs_devices->devices);
+                mutex_unlock(&fs_devices->device_list_mutex);
+
                 device->fs_devices = fs_devices;
                 fs_devices->num_devices++;
         }
@@ -418,10 +434,12 @@ static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
         INIT_LIST_HEAD(&fs_devices->devices);
         INIT_LIST_HEAD(&fs_devices->alloc_list);
         INIT_LIST_HEAD(&fs_devices->list);
+        mutex_init(&fs_devices->device_list_mutex);
         fs_devices->latest_devid = orig->latest_devid;
         fs_devices->latest_trans = orig->latest_trans;
         memcpy(fs_devices->fsid, orig->fsid, sizeof(fs_devices->fsid));
 
+        mutex_lock(&orig->device_list_mutex);
         list_for_each_entry(orig_dev, &orig->devices, dev_list) {
                 device = kzalloc(sizeof(*device), GFP_NOFS);
                 if (!device)
@@ -443,8 +461,10 @@ static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig)
                 device->fs_devices = fs_devices;
                 fs_devices->num_devices++;
         }
+        mutex_unlock(&orig->device_list_mutex);
         return fs_devices;
 error:
+        mutex_unlock(&orig->device_list_mutex);
         free_fs_devices(fs_devices);
         return ERR_PTR(-ENOMEM);
 }
@@ -455,6 +475,7 @@ int btrfs_close_extra_devices(struct btrfs_fs_devices *fs_devices)
 
         mutex_lock(&uuid_mutex);
 again:
+        mutex_lock(&fs_devices->device_list_mutex);
         list_for_each_entry_safe(device, next, &fs_devices->devices, dev_list) {
                 if (device->in_fs_metadata)
                         continue;
@@ -474,6 +495,7 @@ again:
                 kfree(device->name);
                 kfree(device);
         }
+        mutex_unlock(&fs_devices->device_list_mutex);
 
         if (fs_devices->seed) {
                 fs_devices = fs_devices->seed;
@@ -594,6 +616,9 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
                 device->in_fs_metadata = 0;
                 device->mode = flags;
 
+                if (!blk_queue_nonrot(bdev_get_queue(bdev)))
+                        fs_devices->rotating = 1;
+
                 fs_devices->open_devices++;
                 if (device->writeable) {
                         fs_devices->rw_devices++;
@@ -1121,12 +1146,14 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
 
                 device = NULL;
                 devices = &root->fs_info->fs_devices->devices;
+                mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
                 list_for_each_entry(tmp, devices, dev_list) {
                         if (tmp->in_fs_metadata && !tmp->bdev) {
                                 device = tmp;
                                 break;
                         }
                 }
+                mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
                 bdev = NULL;
                 bh = NULL;
                 disk_super = NULL;
@@ -1181,7 +1208,16 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
                 goto error_brelse;
 
         device->in_fs_metadata = 0;
+
+        /*
+         * the device list mutex makes sure that we don't change
+         * the device list while someone else is writing out all
+         * the device supers.
+         */
+        mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
         list_del_init(&device->dev_list);
+        mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
+
         device->fs_devices->num_devices--;
 
         next_device = list_entry(root->fs_info->fs_devices->devices.next,
@@ -1275,6 +1311,7 @@ static int btrfs_prepare_sprout(struct btrfs_trans_handle *trans,
         seed_devices->opened = 1;
         INIT_LIST_HEAD(&seed_devices->devices);
         INIT_LIST_HEAD(&seed_devices->alloc_list);
+        mutex_init(&seed_devices->device_list_mutex);
         list_splice_init(&fs_devices->devices, &seed_devices->devices);
         list_splice_init(&fs_devices->alloc_list, &seed_devices->alloc_list);
         list_for_each_entry(device, &seed_devices->devices, dev_list) {
@@ -1400,6 +1437,10 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
         mutex_lock(&root->fs_info->volume_mutex);
 
         devices = &root->fs_info->fs_devices->devices;
+        /*
+         * we have the volume lock, so we don't need the extra
+         * device list mutex while reading the list here.
+         */
         list_for_each_entry(device, devices, dev_list) {
                 if (device->bdev == bdev) {
                         ret = -EEXIST;
@@ -1454,6 +1495,12 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
         }
 
         device->fs_devices = root->fs_info->fs_devices;
+
+        /*
+         * we don't want write_supers to jump in here with our device
+         * half setup
+         */
+        mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
         list_add(&device->dev_list, &root->fs_info->fs_devices->devices);
         list_add(&device->dev_alloc_list,
                  &root->fs_info->fs_devices->alloc_list);
@@ -1462,6 +1509,9 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
         root->fs_info->fs_devices->rw_devices++;
         root->fs_info->fs_devices->total_rw_bytes += device->total_bytes;
 
+        if (!blk_queue_nonrot(bdev_get_queue(bdev)))
+                root->fs_info->fs_devices->rotating = 1;
+
         total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
         btrfs_set_super_total_bytes(&root->fs_info->super_copy,
                                     total_bytes + device->total_bytes);
@@ -1469,6 +1519,7 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
         total_bytes = btrfs_super_num_devices(&root->fs_info->super_copy);
         btrfs_set_super_num_devices(&root->fs_info->super_copy,
                                     total_bytes + 1);
+        mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
 
         if (seeding_dev) {
                 ret = init_first_rw_device(trans, root, device);
@@ -1671,8 +1722,6 @@ static int btrfs_relocate_chunk(struct btrfs_root *root,
         int ret;
         int i;
 
-        printk(KERN_INFO "btrfs relocating chunk %llu\n",
-               (unsigned long long)chunk_offset);
         root = root->fs_info->chunk_root;
         extent_root = root->fs_info->extent_root;
         em_tree = &root->fs_info->mapping_tree.map_tree;