Merge branch 'allocator' of git://git.kernel.org/pub/scm/linux/kernel/git/arne/btrfs...
[sfrench/cifs-2.6.git] / fs / btrfs / volumes.c
index cd0b31a9ba3d360145b63f902b1e8ec61842f7a4..f777145203df0397d40baa67a87f91d4860e4052 100644 (file)
@@ -805,10 +805,7 @@ int find_free_dev_extent(struct btrfs_trans_handle *trans,
        /* we don't want to overwrite the superblock on the drive,
         * so we make sure to start at an offset of at least 1MB
         */
-       search_start = 1024 * 1024;
-
-       if (root->fs_info->alloc_start + num_bytes <= search_end)
-               search_start = max(root->fs_info->alloc_start, search_start);
+       search_start = max(root->fs_info->alloc_start, 1024ull * 1024);
 
        max_hole_start = search_start;
        max_hole_size = 0;
@@ -2227,275 +2224,204 @@ static int btrfs_add_system_chunk(struct btrfs_trans_handle *trans,
        return 0;
 }
 
-static noinline u64 chunk_bytes_by_type(u64 type, u64 calc_size,
-                                       int num_stripes, int sub_stripes)
+/*
+ * sort the devices in descending order by max_avail, total_avail
+ */
+static int btrfs_cmp_device_info(const void *a, const void *b)
 {
-       if (type & (BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_DUP))
-               return calc_size;
-       else if (type & BTRFS_BLOCK_GROUP_RAID10)
-               return calc_size * (num_stripes / sub_stripes);
-       else
-               return calc_size * num_stripes;
-}
+       const struct btrfs_device_info *di_a = a;
+       const struct btrfs_device_info *di_b = b;
 
-/* Used to sort the devices by max_avail(descending sort) */
-int btrfs_cmp_device_free_bytes(const void *dev_info1, const void *dev_info2)
-{
-       if (((struct btrfs_device_info *)dev_info1)->max_avail >
-           ((struct btrfs_device_info *)dev_info2)->max_avail)
+       if (di_a->max_avail > di_b->max_avail)
                return -1;
-       else if (((struct btrfs_device_info *)dev_info1)->max_avail <
-                ((struct btrfs_device_info *)dev_info2)->max_avail)
+       if (di_a->max_avail < di_b->max_avail)
                return 1;
-       else
-               return 0;
+       if (di_a->total_avail > di_b->total_avail)
+               return -1;
+       if (di_a->total_avail < di_b->total_avail)
+               return 1;
+       return 0;
 }
 
-static int __btrfs_calc_nstripes(struct btrfs_fs_devices *fs_devices, u64 type,
-                                int *num_stripes, int *min_stripes,
-                                int *sub_stripes)
+static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
+                              struct btrfs_root *extent_root,
+                              struct map_lookup **map_ret,
+                              u64 *num_bytes_out, u64 *stripe_size_out,
+                              u64 start, u64 type)
 {
-       *num_stripes = 1;
-       *min_stripes = 1;
-       *sub_stripes = 0;
+       struct btrfs_fs_info *info = extent_root->fs_info;
+       struct btrfs_fs_devices *fs_devices = info->fs_devices;
+       struct list_head *cur;
+       struct map_lookup *map = NULL;
+       struct extent_map_tree *em_tree;
+       struct extent_map *em;
+       struct btrfs_device_info *devices_info = NULL;
+       u64 total_avail;
+       int num_stripes;        /* total number of stripes to allocate */
+       int sub_stripes;        /* sub_stripes info for map */
+       int dev_stripes;        /* stripes per dev */
+       int devs_max;           /* max devs to use */
+       int devs_min;           /* min devs needed */
+       int devs_increment;     /* ndevs has to be a multiple of this */
+       int ncopies;            /* how many copies to data has */
+       int ret;
+       u64 max_stripe_size;
+       u64 max_chunk_size;
+       u64 stripe_size;
+       u64 num_bytes;
+       int ndevs;
+       int i;
+       int j;
 
-       if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
-               *num_stripes = fs_devices->rw_devices;
-               *min_stripes = 2;
-       }
-       if (type & (BTRFS_BLOCK_GROUP_DUP)) {
-               *num_stripes = 2;
-               *min_stripes = 2;
-       }
-       if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
-               if (fs_devices->rw_devices < 2)
-                       return -ENOSPC;
-               *num_stripes = 2;
-               *min_stripes = 2;
-       }
-       if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
-               *num_stripes = fs_devices->rw_devices;
-               if (*num_stripes < 4)
-                       return -ENOSPC;
-               *num_stripes &= ~(u32)1;
-               *sub_stripes = 2;
-               *min_stripes = 4;
+       if ((type & BTRFS_BLOCK_GROUP_RAID1) &&
+           (type & BTRFS_BLOCK_GROUP_DUP)) {
+               WARN_ON(1);
+               type &= ~BTRFS_BLOCK_GROUP_DUP;
        }
 
-       return 0;
-}
+       if (list_empty(&fs_devices->alloc_list))
+               return -ENOSPC;
 
-static u64 __btrfs_calc_stripe_size(struct btrfs_fs_devices *fs_devices,
-                                   u64 proposed_size, u64 type,
-                                   int num_stripes, int small_stripe)
-{
-       int min_stripe_size = 1 * 1024 * 1024;
-       u64 calc_size = proposed_size;
-       u64 max_chunk_size = calc_size;
-       int ncopies = 1;
+       sub_stripes = 1;
+       dev_stripes = 1;
+       devs_increment = 1;
+       ncopies = 1;
+       devs_max = 0;   /* 0 == as many as possible */
+       devs_min = 1;
 
-       if (type & (BTRFS_BLOCK_GROUP_RAID1 |
-                   BTRFS_BLOCK_GROUP_DUP |
-                   BTRFS_BLOCK_GROUP_RAID10))
+       /*
+        * define the properties of each RAID type.
+        * FIXME: move this to a global table and use it in all RAID
+        * calculation code
+        */
+       if (type & (BTRFS_BLOCK_GROUP_DUP)) {
+               dev_stripes = 2;
+               ncopies = 2;
+               devs_max = 1;
+       } else if (type & (BTRFS_BLOCK_GROUP_RAID0)) {
+               devs_min = 2;
+       } else if (type & (BTRFS_BLOCK_GROUP_RAID1)) {
+               devs_increment = 2;
                ncopies = 2;
+               devs_max = 2;
+               devs_min = 2;
+       } else if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
+               sub_stripes = 2;
+               devs_increment = 2;
+               ncopies = 2;
+               devs_min = 4;
+       } else {
+               devs_max = 1;
+       }
 
        if (type & BTRFS_BLOCK_GROUP_DATA) {
-               max_chunk_size = 10 * calc_size;
-               min_stripe_size = 64 * 1024 * 1024;
+               max_stripe_size = 1024 * 1024 * 1024;
+               max_chunk_size = 10 * max_stripe_size;
        } else if (type & BTRFS_BLOCK_GROUP_METADATA) {
-               max_chunk_size = 256 * 1024 * 1024;
-               min_stripe_size = 32 * 1024 * 1024;
+               max_stripe_size = 256 * 1024 * 1024;
+               max_chunk_size = max_stripe_size;
        } else if (type & BTRFS_BLOCK_GROUP_SYSTEM) {
-               calc_size = 8 * 1024 * 1024;
-               max_chunk_size = calc_size * 2;
-               min_stripe_size = 1 * 1024 * 1024;
+               max_stripe_size = 8 * 1024 * 1024;
+               max_chunk_size = 2 * max_stripe_size;
+       } else {
+               printk(KERN_ERR "btrfs: invalid chunk type 0x%llx requested\n",
+                      type);
+               BUG_ON(1);
        }
 
        /* we don't want a chunk larger than 10% of writeable space */
        max_chunk_size = min(div_factor(fs_devices->total_rw_bytes, 1),
                             max_chunk_size);
 
-       if (calc_size * num_stripes > max_chunk_size * ncopies) {
-               calc_size = max_chunk_size * ncopies;
-               do_div(calc_size, num_stripes);
-               do_div(calc_size, BTRFS_STRIPE_LEN);
-               calc_size *= BTRFS_STRIPE_LEN;
-       }
+       devices_info = kzalloc(sizeof(*devices_info) * fs_devices->rw_devices,
+                              GFP_NOFS);
+       if (!devices_info)
+               return -ENOMEM;
 
-       /* we don't want tiny stripes */
-       if (!small_stripe)
-               calc_size = max_t(u64, min_stripe_size, calc_size);
+       cur = fs_devices->alloc_list.next;
 
        /*
-        * we're about to do_div by the BTRFS_STRIPE_LEN so lets make sure
-        * we end up with something bigger than a stripe
+        * in the first pass through the devices list, we gather information
+        * about the available holes on each device.
         */
-       calc_size = max_t(u64, calc_size, BTRFS_STRIPE_LEN);
-
-       do_div(calc_size, BTRFS_STRIPE_LEN);
-       calc_size *= BTRFS_STRIPE_LEN;
-
-       return calc_size;
-}
-
-static struct map_lookup *__shrink_map_lookup_stripes(struct map_lookup *map,
-                                                     int num_stripes)
-{
-       struct map_lookup *new;
-       size_t len = map_lookup_size(num_stripes);
-
-       BUG_ON(map->num_stripes < num_stripes);
-
-       if (map->num_stripes == num_stripes)
-               return map;
-
-       new = kmalloc(len, GFP_NOFS);
-       if (!new) {
-               /* just change map->num_stripes */
-               map->num_stripes = num_stripes;
-               return map;
-       }
-
-       memcpy(new, map, len);
-       new->num_stripes = num_stripes;
-       kfree(map);
-       return new;
-}
+       ndevs = 0;
+       while (cur != &fs_devices->alloc_list) {
+               struct btrfs_device *device;
+               u64 max_avail;
+               u64 dev_offset;
 
-/*
- * helper to allocate device space from btrfs_device_info, in which we stored
- * max free space information of every device. It is used when we can not
- * allocate chunks by default size.
- *
- * By this helper, we can allocate a new chunk as larger as possible.
- */
-static int __btrfs_alloc_tiny_space(struct btrfs_trans_handle *trans,
-                                   struct btrfs_fs_devices *fs_devices,
-                                   struct btrfs_device_info *devices,
-                                   int nr_device, u64 type,
-                                   struct map_lookup **map_lookup,
-                                   int min_stripes, u64 *stripe_size)
-{
-       int i, index, sort_again = 0;
-       int min_devices = min_stripes;
-       u64 max_avail, min_free;
-       struct map_lookup *map = *map_lookup;
-       int ret;
+               device = list_entry(cur, struct btrfs_device, dev_alloc_list);
 
-       if (nr_device < min_stripes)
-               return -ENOSPC;
+               cur = cur->next;
 
-       btrfs_descending_sort_devices(devices, nr_device);
+               if (!device->writeable) {
+                       printk(KERN_ERR
+                              "btrfs: read-only device in alloc_list\n");
+                       WARN_ON(1);
+                       continue;
+               }
 
-       max_avail = devices[0].max_avail;
-       if (!max_avail)
-               return -ENOSPC;
+               if (!device->in_fs_metadata)
+                       continue;
 
-       for (i = 0; i < nr_device; i++) {
-               /*
-                * if dev_offset = 0, it means the free space of this device
-                * is less than what we need, and we didn't search max avail
-                * extent on this device, so do it now.
+               if (device->total_bytes > device->bytes_used)
+                       total_avail = device->total_bytes - device->bytes_used;
+               else
+                       total_avail = 0;
+               /* avail is off by max(alloc_start, 1MB), but that is the same
+                * for all devices, so it doesn't hurt the sorting later on
                 */
-               if (!devices[i].dev_offset) {
-                       ret = find_free_dev_extent(trans, devices[i].dev,
-                                                  max_avail,
-                                                  &devices[i].dev_offset,
-                                                  &devices[i].max_avail);
-                       if (ret != 0 && ret != -ENOSPC)
-                               return ret;
-                       sort_again = 1;
-               }
-       }
 
-       /* we update the max avail free extent of each devices, sort again */
-       if (sort_again)
-               btrfs_descending_sort_devices(devices, nr_device);
-
-       if (type & BTRFS_BLOCK_GROUP_DUP)
-               min_devices = 1;
+               ret = find_free_dev_extent(trans, device,
+                                          max_stripe_size * dev_stripes,
+                                          &dev_offset, &max_avail);
+               if (ret && ret != -ENOSPC)
+                       goto error;
 
-       if (!devices[min_devices - 1].max_avail)
-               return -ENOSPC;
+               if (ret == 0)
+                       max_avail = max_stripe_size * dev_stripes;
 
-       max_avail = devices[min_devices - 1].max_avail;
-       if (type & BTRFS_BLOCK_GROUP_DUP)
-               do_div(max_avail, 2);
+               if (max_avail < BTRFS_STRIPE_LEN * dev_stripes)
+                       continue;
 
-       max_avail = __btrfs_calc_stripe_size(fs_devices, max_avail, type,
-                                            min_stripes, 1);
-       if (type & BTRFS_BLOCK_GROUP_DUP)
-               min_free = max_avail * 2;
-       else
-               min_free = max_avail;
+               devices_info[ndevs].dev_offset = dev_offset;
+               devices_info[ndevs].max_avail = max_avail;
+               devices_info[ndevs].total_avail = total_avail;
+               devices_info[ndevs].dev = device;
+               ++ndevs;
+       }
 
-       if (min_free > devices[min_devices - 1].max_avail)
-               return -ENOSPC;
+       /*
+        * now sort the devices by hole size / available space
+        */
+       sort(devices_info, ndevs, sizeof(struct btrfs_device_info),
+            btrfs_cmp_device_info, NULL);
 
-       map = __shrink_map_lookup_stripes(map, min_stripes);
-       *stripe_size = max_avail;
+       /* round down to number of usable stripes */
+       ndevs -= ndevs % devs_increment;
 
-       index = 0;
-       for (i = 0; i < min_stripes; i++) {
-               map->stripes[i].dev = devices[index].dev;
-               map->stripes[i].physical = devices[index].dev_offset;
-               if (type & BTRFS_BLOCK_GROUP_DUP) {
-                       i++;
-                       map->stripes[i].dev = devices[index].dev;
-                       map->stripes[i].physical = devices[index].dev_offset +
-                                                  max_avail;
-               }
-               index++;
+       if (ndevs < devs_increment * sub_stripes || ndevs < devs_min) {
+               ret = -ENOSPC;
+               goto error;
        }
-       *map_lookup = map;
-
-       return 0;
-}
 
-static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
-                              struct btrfs_root *extent_root,
-                              struct map_lookup **map_ret,
-                              u64 *num_bytes, u64 *stripe_size,
-                              u64 start, u64 type)
-{
-       struct btrfs_fs_info *info = extent_root->fs_info;
-       struct btrfs_device *device = NULL;
-       struct btrfs_fs_devices *fs_devices = info->fs_devices;
-       struct list_head *cur;
-       struct map_lookup *map;
-       struct extent_map_tree *em_tree;
-       struct extent_map *em;
-       struct btrfs_device_info *devices_info;
-       struct list_head private_devs;
-       u64 calc_size = 1024 * 1024 * 1024;
-       u64 min_free;
-       u64 avail;
-       u64 dev_offset;
-       int num_stripes;
-       int min_stripes;
-       int sub_stripes;
-       int min_devices;        /* the min number of devices we need */
-       int i;
-       int ret;
-       int index;
+       if (devs_max && ndevs > devs_max)
+               ndevs = devs_max;
+       /*
+        * the primary goal is to maximize the number of stripes, so use as many
+        * devices as possible, even if the stripes are not maximum sized.
+        */
+       stripe_size = devices_info[ndevs-1].max_avail;
+       num_stripes = ndevs * dev_stripes;
 
-       if ((type & BTRFS_BLOCK_GROUP_RAID1) &&
-           (type & BTRFS_BLOCK_GROUP_DUP)) {
-               WARN_ON(1);
-               type &= ~BTRFS_BLOCK_GROUP_DUP;
+       if (stripe_size * num_stripes > max_chunk_size * ncopies) {
+               stripe_size = max_chunk_size * ncopies;
+               do_div(stripe_size, num_stripes);
        }
-       if (list_empty(&fs_devices->alloc_list))
-               return -ENOSPC;
 
-       ret = __btrfs_calc_nstripes(fs_devices, type, &num_stripes,
-                                   &min_stripes, &sub_stripes);
-       if (ret)
-               return ret;
-
-       devices_info = kzalloc(sizeof(*devices_info) * fs_devices->rw_devices,
-                              GFP_NOFS);
-       if (!devices_info)
-               return -ENOMEM;
+       do_div(stripe_size, dev_stripes);
+       do_div(stripe_size, BTRFS_STRIPE_LEN);
+       stripe_size *= BTRFS_STRIPE_LEN;
 
        map = kmalloc(map_lookup_size(num_stripes), GFP_NOFS);
        if (!map) {
@@ -2504,85 +2430,12 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
        }
        map->num_stripes = num_stripes;
 
-       cur = fs_devices->alloc_list.next;
-       index = 0;
-       i = 0;
-
-       calc_size = __btrfs_calc_stripe_size(fs_devices, calc_size, type,
-                                            num_stripes, 0);
-
-       if (type & BTRFS_BLOCK_GROUP_DUP) {
-               min_free = calc_size * 2;
-               min_devices = 1;
-       } else {
-               min_free = calc_size;
-               min_devices = min_stripes;
-       }
-
-       INIT_LIST_HEAD(&private_devs);
-       while (index < num_stripes) {
-               device = list_entry(cur, struct btrfs_device, dev_alloc_list);
-               BUG_ON(!device->writeable);
-               if (device->total_bytes > device->bytes_used)
-                       avail = device->total_bytes - device->bytes_used;
-               else
-                       avail = 0;
-               cur = cur->next;
-
-               if (device->in_fs_metadata && avail >= min_free) {
-                       ret = find_free_dev_extent(trans, device, min_free,
-                                                  &devices_info[i].dev_offset,
-                                                  &devices_info[i].max_avail);
-                       if (ret == 0) {
-                               list_move_tail(&device->dev_alloc_list,
-                                              &private_devs);
-                               map->stripes[index].dev = device;
-                               map->stripes[index].physical =
-                                               devices_info[i].dev_offset;
-                               index++;
-                               if (type & BTRFS_BLOCK_GROUP_DUP) {
-                                       map->stripes[index].dev = device;
-                                       map->stripes[index].physical =
-                                               devices_info[i].dev_offset +
-                                               calc_size;
-                                       index++;
-                               }
-                       } else if (ret != -ENOSPC)
-                               goto error;
-
-                       devices_info[i].dev = device;
-                       i++;
-               } else if (device->in_fs_metadata &&
-                          avail >= BTRFS_STRIPE_LEN) {
-                       devices_info[i].dev = device;
-                       devices_info[i].max_avail = avail;
-                       i++;
-               }
-
-               if (cur == &fs_devices->alloc_list)
-                       break;
-       }
-
-       list_splice(&private_devs, &fs_devices->alloc_list);
-       if (index < num_stripes) {
-               if (index >= min_stripes) {
-                       num_stripes = index;
-                       if (type & (BTRFS_BLOCK_GROUP_RAID10)) {
-                               num_stripes /= sub_stripes;
-                               num_stripes *= sub_stripes;
-                       }
-
-                       map = __shrink_map_lookup_stripes(map, num_stripes);
-               } else if (i >= min_devices) {
-                       ret = __btrfs_alloc_tiny_space(trans, fs_devices,
-                                                      devices_info, i, type,
-                                                      &map, min_stripes,
-                                                      &calc_size);
-                       if (ret)
-                               goto error;
-               } else {
-                       ret = -ENOSPC;
-                       goto error;
+       for (i = 0; i < ndevs; ++i) {
+               for (j = 0; j < dev_stripes; ++j) {
+                       int s = i * dev_stripes + j;
+                       map->stripes[s].dev = devices_info[i].dev;
+                       map->stripes[s].physical = devices_info[i].dev_offset +
+                                                  j * stripe_size;
                }
        }
        map->sector_size = extent_root->sectorsize;
@@ -2593,11 +2446,12 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
        map->sub_stripes = sub_stripes;
 
        *map_ret = map;
-       *stripe_size = calc_size;
-       *num_bytes = chunk_bytes_by_type(type, calc_size,
-                                        map->num_stripes, sub_stripes);
+       num_bytes = stripe_size * (num_stripes / ncopies);
 
-       trace_btrfs_chunk_alloc(info->chunk_root, map, start, *num_bytes);
+       *stripe_size_out = stripe_size;
+       *num_bytes_out = num_bytes;
+
+       trace_btrfs_chunk_alloc(info->chunk_root, map, start, num_bytes);
 
        em = alloc_extent_map();
        if (!em) {
@@ -2606,7 +2460,7 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
        }
        em->bdev = (struct block_device *)map;
        em->start = start;
-       em->len = *num_bytes;
+       em->len = num_bytes;
        em->block_start = 0;
        em->block_len = em->len;
 
@@ -2619,20 +2473,21 @@ static int __btrfs_alloc_chunk(struct btrfs_trans_handle *trans,
 
        ret = btrfs_make_block_group(trans, extent_root, 0, type,
                                     BTRFS_FIRST_CHUNK_TREE_OBJECTID,
-                                    start, *num_bytes);
+                                    start, num_bytes);
        BUG_ON(ret);
 
-       index = 0;
-       while (index < map->num_stripes) {
-               device = map->stripes[index].dev;
-               dev_offset = map->stripes[index].physical;
+       for (i = 0; i < map->num_stripes; ++i) {
+               struct btrfs_device *device;
+               u64 dev_offset;
+
+               device = map->stripes[i].dev;
+               dev_offset = map->stripes[i].physical;
 
                ret = btrfs_alloc_dev_extent(trans, device,
                                info->chunk_root->root_key.objectid,
                                BTRFS_FIRST_CHUNK_TREE_OBJECTID,
-                               start, dev_offset, calc_size);
+                               start, dev_offset, stripe_size);
                BUG_ON(ret);
-               index++;
        }
 
        kfree(devices_info);